WorldWideScience

Sample records for stable legged locomotion

  1. Dynamically Stable Legged Locomotion.

    Science.gov (United States)

    1983-01-27

    balanced itself in 31) using a tabular ctontrol sclwnme. With only thUiee actuated degrees it used a shuffling gait to balance that reminds one of Charlie ... Chaplin . * The present study explores the control of a physical one-legged hopping machine. The objective of using a machine with only one leg was to

  2. Stable walking with asymmetric legs

    International Nuclear Information System (INIS)

    Merker, Andreas; Rummel, Juergen; Seyfarth, Andre

    2011-01-01

    Asymmetric leg function is often an undesired side-effect in artificial legged systems and may reflect functional deficits or variations in the mechanical construction. It can also be found in legged locomotion in humans and animals such as after an accident or in specific gait patterns. So far, it is not clear to what extent differences in the leg function of contralateral limbs can be tolerated during walking or running. Here, we address this issue using a bipedal spring-mass model for simulating walking with compliant legs. With the help of the model, we show that considerable differences between contralateral legs can be tolerated and may even provide advantages to the robustness of the system dynamics. A better understanding of the mechanisms and potential benefits of asymmetric leg operation may help to guide the development of artificial limbs or the design novel therapeutic concepts and rehabilitation strategies.

  3. Proprioceptive Actuation Design for Dynamic Legged locomotion

    Science.gov (United States)

    Kim, Sangbae; Wensing, Patrick; Biomimetic Robotics Lab Team

    Designing an actuator system for highly-dynamic legged locomotion exhibited by animals has been one of the grand challenges in robotics research. Conventional actuators designed for manufacturing applications have difficulty satisfying challenging requirements for high-speed locomotion, such as the need for high torque density and the ability to manage dynamic physical interactions. It is critical to introduce a new actuator design paradigm and provide guidelines for its incorporation in future mobile robots for research and industry. To this end, we suggest a paradigm called proprioceptive actuation, which enables highly- dynamic operation in legged machines. Proprioceptive actuation uses collocated force control at the joints to effectively control contact interactions at the feet under dynamic conditions. In the realm of legged machines, this paradigm provides a unique combination of high torque density, high-bandwidth force control, and the ability to mitigate impacts through backdrivability. Results show that the proposed design provides an impact mitigation factor that is comparable to other quadruped designs with series springs to handle impact. The paradigm is shown to enable the MIT Cheetah to manage the application of contact forces during dynamic bounding, with results given down to contact times of 85ms and peak forces over 450N. As a result, the MIT Cheetah achieves high-speed 3D running up to 13mph and jumping over an 18-inch high obstacle. The project is sponsored by DARPA M3 program.

  4. Trunk orientation causes asymmetries in leg function in small bird terrestrial locomotion.

    Science.gov (United States)

    Andrada, Emanuel; Rode, Christian; Sutedja, Yefta; Nyakatura, John A; Blickhan, Reinhard

    2014-12-22

    In contrast to the upright trunk in humans, trunk orientation in most birds is almost horizontal (pronograde). It is conceivable that the orientation of the heavy trunk strongly influences the dynamics of bipedal terrestrial locomotion. Here, we analyse for the first time the effects of a pronograde trunk orientation on leg function and stability during bipedal locomotion. For this, we first inferred the leg function and trunk control strategy applied by a generalized small bird during terrestrial locomotion by analysing synchronously recorded kinematic (three-dimensional X-ray videography) and kinetic (three-dimensional force measurement) quail locomotion data. Then, by simulating quail gaits using a simplistic bioinspired numerical model which made use of parameters obtained in in vivo experiments with real quail, we show that the observed asymmetric leg function (left-skewed ground reaction force and longer leg at touchdown than at lift-off) is necessary for pronograde steady-state locomotion. In addition, steady-state locomotion becomes stable for specific morphological parameters. For quail-like parameters, the most common stable solution is grounded running, a gait preferred by quail and most of the other small birds. We hypothesize that stability of bipedal locomotion is a functional demand that, depending on trunk orientation and centre of mass location, constrains basic hind limb morphology and function, such as leg length, leg stiffness and leg damping. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  5. Modeling posture-dependent leg actuation in sagittal plane locomotion

    International Nuclear Information System (INIS)

    Schmitt, J; Clark, J

    2009-01-01

    The spring loaded inverted pendulum template has been shown to accurately model the steady locomotion dynamics of a variety of running animals, and has served as the inspiration for an entire class of dynamic running robots. While the template models the leg dynamics by an energy-conserving spring, insects and animals have structures that dissipate, store and produce energy during a stance phase. Recent investigations into the spring-like properties of limbs, as well as animal response to drop-step perturbations, suggest that animals use their legs to manage energy storage and dissipation, and that this management is important for gait stability. In this paper, we extend our previous analysis of control of the spring loaded inverted pendulum template via changes in the leg touch-down angle to include energy variations during the stance phase. Energy variations are incorporated through leg actuation that varies the force-free leg length during the stance phase, yet maintains qualitatively correct force and velocity profiles. In contrast to the partially asymptotically stable gaits identified in previous analyses, incorporating energy and leg angle variations in this manner produces complete asymptotic stability. Drop-step perturbation simulations reveal that the control strategy is rather robust, with gaits recovering from drops of up to 30% of the nominal hip height.

  6. Modeling posture-dependent leg actuation in sagittal plane locomotion

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, J [Department of Mechanical Engineering, Oregon State University, Corvallis, OR 97331 (United States); Clark, J, E-mail: schmitjo@engr.orst.ed [Department of Mechanical Engineering, Florida State University, Tallahassee, FL 32310 (United States)

    2009-12-15

    The spring loaded inverted pendulum template has been shown to accurately model the steady locomotion dynamics of a variety of running animals, and has served as the inspiration for an entire class of dynamic running robots. While the template models the leg dynamics by an energy-conserving spring, insects and animals have structures that dissipate, store and produce energy during a stance phase. Recent investigations into the spring-like properties of limbs, as well as animal response to drop-step perturbations, suggest that animals use their legs to manage energy storage and dissipation, and that this management is important for gait stability. In this paper, we extend our previous analysis of control of the spring loaded inverted pendulum template via changes in the leg touch-down angle to include energy variations during the stance phase. Energy variations are incorporated through leg actuation that varies the force-free leg length during the stance phase, yet maintains qualitatively correct force and velocity profiles. In contrast to the partially asymptotically stable gaits identified in previous analyses, incorporating energy and leg angle variations in this manner produces complete asymptotic stability. Drop-step perturbation simulations reveal that the control strategy is rather robust, with gaits recovering from drops of up to 30% of the nominal hip height.

  7. Dynamic Locomotion With Four and Six-Legged Robots

    National Research Council Canada - National Science Library

    Buehler, M; Saranli, U; Papadopoulos, D; Koditschek, D

    2000-01-01

    .... The Scout II quadruped runs on flat ground in a bounding gait, and was motivated by an effort to understand the minimal mechanical design and control complexity for dynamically stable locomotion...

  8. Hybrid control and motion planning of dynamical legged locomotion

    CERN Document Server

    2012-01-01

    "This book provides a comprehensive presentation of issues and challenges faced by researchers and practicing engineers in motion planning and hybrid control of dynamical legged locomotion. The major features range from offline and online motion planning algorithms to generate desired feasible periodic walking and running motions and tow-level control schemes, including within-stride feedback laws, continuous time update laws and event-based update laws, to asymptotically stabilize the generated desired periodic orbits. This book describes the current state of the art and future directions across all domains of dynamical legged locomotion so that readers can extend proposed motion planning algorithms and control methodologies to other types of planar and 3D legged robots".

  9. Mechanical aspects of legged locomotion control.

    Science.gov (United States)

    Koditschek, Daniel E; Full, Robert J; Buehler, Martin

    2004-07-01

    We review the mechanical components of an approach to motion science that enlists recent progress in neurophysiology, biomechanics, control systems engineering, and non-linear dynamical systems to explore the integration of muscular, skeletal, and neural mechanics that creates effective locomotor behavior. We use rapid arthropod terrestrial locomotion as the model system because of the wealth of experimental data available. With this foundation, we list a set of hypotheses for the control of movement, outline their mathematical underpinning and show how they have inspired the design of the hexapedal robot, RHex.

  10. Theoretical and experimental study on a compliant flipper-leg during terrestrial locomotion.

    Science.gov (United States)

    Fang, Tao; Zhou, Youcheng; Li, Shikun; Xu, Min; Liang, Haiyi; Li, Weihua; Zhang, Shiwu

    2016-08-17

    An amphibious robot with straight compliant flipper-legs can conquer various amphibious environments. The robot can rotate its flipper-legs and utilize their large deflection to walk on rough terrain, and it can oscillate the straight flipper-legs to propel itself underwater. This paper focuses on the dynamics of the compliant straight flipper-legs during terrestrial locomotion by modeling its deformation dynamically with large deflection theory and simulating it to investigate the parameters of locomotion such as trajectory, velocity, and propulsion. To validate the theoretical model of dynamic locomotion, a single-leg experimental platform is used to explore the flipper-legs in motion with various structural and kinematic parameters. Furthermore, a robotic platform mounting with four compliant flipper-legs is also developed and used to experiment with locomotion. The trajectories of the rotating axle of the compliant flipper-leg during locomotion were approximately coincidental in simulation and in experiments. The speed of locomotion and cost of transport during locomotion were explored and analyzed. The performance of different types of compliant flipper-legs during locomotion shows that varying the degrees of stiffness will have a significant effect on their locomotion. The dynamic model and analysis of the compliant flipper-leg for terrestrial locomotion facilitates the ability of amphibious robots to conquer complex environments.

  11. Effects of wearing lower leg compression sleeves on locomotion economy.

    Science.gov (United States)

    Kurz, Eduard; Anders, Christoph

    2018-02-15

    The purpose of this investigation was to assess the effect of compression sleeves on muscle activation cost during locomotion. Twenty-two recreationally active men (age: 25 ± 3 years) ran on a treadmill at four different speeds (ordered sequence of 2.8, 3.3, 2.2, and 3.9 m/s). The tests were performed without (control situation, CON) and while wearing specially designed lower leg compression sleeves (SL). Myoelectric activity of five lower leg muscles (tibialis anterior, fibularis longus, lateral and medial head of gastrocnemius, and soleus) was captured using Surface EMG. To assess muscle activation cost, the cumulative muscle activity per distance travelled (CMAPD) of the CON and SL situations was determined. Repeated measures analyses of variance were performed separately for each muscle. The analyses revealed a reduced lower leg muscle activation cost with respect to test situation for SL for all muscles (p  0.18). The respective significant reductions of CMAPD values during SL ranged between 4% and 16% and were largest at 2.8 m/s. The findings presented point towards an improved muscle activation cost while wearing lower leg compression sleeves during locomotion that have potential to postpone muscle fatigue.

  12. Modelling of dynamically stable AR-601M robot locomotion in Simulink

    Directory of Open Access Journals (Sweden)

    Khusainov Ramil

    2016-01-01

    Full Text Available Humanoid robots will gradually play an important role in our daily lives. Currently, research on anthropomorphic robots and biped locomotion is one of the most important problems in the field of mobile robotics, and the development of reliable control algorithms for them is a challenging task. In this research two algorithms for stable walking of Russian anthropomorphic robot AR-601M with 41 Degrees of Freedom (DoF are investigated. To achieve a human-like dynamically stable locomotion 6 DoF in each robot leg are controlled with Virtual Height Inverted Pendulum and Preview control methods.

  13. Controlling legs for locomotion-insights from robotics and neurobiology.

    Science.gov (United States)

    Buschmann, Thomas; Ewald, Alexander; von Twickel, Arndt; Büschges, Ansgar

    2015-06-29

    Walking is the most common terrestrial form of locomotion in animals. Its great versatility and flexibility has led to many attempts at building walking machines with similar capabilities. The control of walking is an active research area both in neurobiology and robotics, with a large and growing body of work. This paper gives an overview of the current knowledge on the control of legged locomotion in animals and machines and attempts to give walking control researchers from biology and robotics an overview of the current knowledge in both fields. We try to summarize the knowledge on the neurobiological basis of walking control in animals, emphasizing common principles seen in different species. In a section on walking robots, we review common approaches to walking controller design with a slight emphasis on biped walking control. We show where parallels between robotic and neurobiological walking controllers exist and how robotics and biology may benefit from each other. Finally, we discuss where research in the two fields diverges and suggest ways to bridge these gaps.

  14. Analysis of Foot Slippage Effects on an Actuated Spring-Mass Model of Dynamic Legged Locomotion

    Directory of Open Access Journals (Sweden)

    Yizhar Or

    2016-04-01

    Full Text Available The classical model of spring-loaded inverted pendulum (SLIP and its extensions have been widely accepted as a simple description of dynamic legged locomotion at various scales in humans, legged robots and animals. Similar to the majority of models in the literature, the SLIP model assumes ideal sticking contact of the foot. However, there are practical scenarios of low ground friction that causes foot slippage, which can have a significant influence on dynamic behaviour. In this work, an extension of the SLIP model with two masses and torque actuation is considered, which accounts for possible slippage under Coulomb's friction law. The hybrid dynamics of this model is formulated and numerical simulations under representative parameter values reveal several types of stable periodic solutions with stick-slip transitions. Remarkably, it is found that slippage due to low friction can sometimes increase average speed and improve energetic efficiency by significantly reducing the mechanical cost of transport.

  15. Mechatronics by Analogy and Application to Legged Locomotion

    Science.gov (United States)

    Ragusila, Victor

    determined, the original mechanism is optimized such that its dynamic behaviour is analogous. It is shown that, if this analogy is achieved, the control system designed based on the simpler mechanisms can be directly implemented to the more complex system, and their dynamic behaviours are close enough for the system performance to be effectively the same. Finally it is shown that, for the employed objective of fast legged locomotion, the proposed methodology achieves a better design than Reduction-by-Feedback, a competing methodology that uses control layers to simplify the dynamics of the system.

  16. The leg stiffnesses animals use may improve the stability of locomotion.

    Science.gov (United States)

    Shen, ZhuoHua; Seipel, Justin

    2015-07-21

    Despite a wide diversity of running animals, their leg stiffness normalized by animal size and weight (a relative leg stiffness) resides in a narrow range between 7 and 27. Here we determine if the stability of locomotion could be a driving factor for the tight distribution of animal leg stiffness. We simulated an established physics-based model (the actuated Spring-Loaded Inverted Pendulum model) of animal running and found that, with the same energetic cost, perturbations to locomotion are optimally corrected when relative leg stiffness is within the biologically observed range. Here we show that the stability of locomotion, in combination with energetic cost, could be a significant factor influencing the nearly universally observed animal relative leg stiffness range. The energetic cost of locomotion has been widely acknowledged as influencing the evolution of physiology and locomotion behaviors. Specifically, its potential importance for relative leg stiffness has been demonstrated. Here, we demonstrate that stability of locomotion may also be a significant factor influencing relative leg stiffness. Published by Elsevier Ltd.

  17. Comparison of kinematic and dynamic leg trajectory optimization techniques for biped robot locomotion

    Science.gov (United States)

    Khusainov, R.; Klimchik, A.; Magid, E.

    2017-01-01

    The paper presents comparison analysis of two approaches in defining leg trajectories for biped locomotion. The first one operates only with kinematic limitations of leg joints and finds the maximum possible locomotion speed for given limits. The second approach defines leg trajectories from the dynamic stability point of view and utilizes ZMP criteria. We show that two methods give different trajectories and demonstrate that trajectories based on pure dynamic optimization cannot be realized due to joint limits. Kinematic optimization provides unstable solution which can be balanced by upper body movement.

  18. A highly adaptive magnetorheological fluid robotic leg for efficient terrestrial locomotion

    Science.gov (United States)

    Jiang, Nan; Sun, Shuaishuai; Ouyang, Yiming; Xu, Min; Li, Weihua; Zhang, Shiwu

    2016-09-01

    To survive in nature, animals adjust the characteristics of their legs or fins to adapt the motion to their environment. Inspired by the locomotion of animals, a study on the tunable stiffness and damping of a leg will help in the development of intelligent locomotion robots. In this paper we report on the development and experiment of a novel and simple robotic leg that can be adapted to the environment via a smart magnetorheological fluid (MRF). The robotic leg consists of a rotation MRF damper, a torsional spring, a ‘foot’ and a ‘leg’. The curved part of the ‘foot’ makes contact with the grounds while the other end is linked to an outer cylinder of the MRF damper with an inelastic cable. The variable force arm rising from the MRF damper and the torsional spring can help the leg adapt to a changing environment. The characteristics of the MRF damper have been investigated and a model is built to describe its mechanical features when different currents are applied to the MRF damper. A test on a linear dynamic test instrument has been conducted to verify the accuracy of the model. The robotic leg is installed in a locomotion platform to investigate the speed of its locomotion and the cost of the transport; the result demonstrated the feasibility and adaptability of the leg when walking on hard terrain. Its simple structure, high adaptability, and easy control of the MRF leg helped in the design and development of a high performance field robot that can adapt to various environments.

  19. Physiological aspects of legged terrestrial locomotion the motor and the machine

    CERN Document Server

    Cavagna, Giovanni

    2017-01-01

    This book offers a succinct but comprehensive description of the mechanics of muscle contraction and legged terrestrial locomotion. It describes on the one hand how the fundamental properties of muscle tissue affect the mechanics of locomotion, and on the other, how the mechanics of locomotion modify the mechanism of muscle operation under different conditions. Further, the book reports on the design and results of experiments conducted with two goals. The first was to describe the physiological function of muscle tissue (which may be considered as the “motor”) contracting at a constant length, during shortening, during lengthening, and under a condition that occurs most frequently in the back-and-forth movement of the limbs during locomotion, namely the stretch-shortening cycle of the active muscle. The second objective was to analyze the interaction between the motor and the “machine” (the skeletal lever system) during walking and running in different scenarios with respect to speed, step frequency,...

  20. Stiffness characteristics of compliant three segment leg with the self-stable region in slow and fast running

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Oh Seok; Ha, Sung Mok; Lee, Dong Ha [Convergence Research Center for WellnessDaegu Gyeongbuk Institute of Science and TechnologyDaegu (Korea, Republic of)

    2016-12-15

    In this paper, we propose the stiffness characteristics of compliant three segment leg that can have a self-stable region in slow and fast running. This proposition can contribute to reducing the control effort and enhancing the locomotion energy efficiency for the compliant three segment legged robot in slow and fast running. Previous research indicated that the running self-stable region of the spring-mass system is located in a relatively fast running region and that of the two segment leg is located in a relatively slow running region. In this paper, we analyze the stiffness characteristics of the spring-mass system and the two segment leg to explain the previous research results. From this analysis, we propose the stiffness characteristics of the compliant three segment leg with a self-stable region in slow and fast running. We further design the compliant three segment leg based on this proposition and check its structural stability. We examine the running self-stable region of this compliant three segment leg to determine whether it has a self-stable region in slow and fast running. We also examine the walking self-stable region of this compliant three segment leg.

  1. Soft Legged Wheel-Based Robot with Terrestrial Locomotion Abilities

    Directory of Open Access Journals (Sweden)

    Ali Sadeghi

    2016-12-01

    Full Text Available In recent years robotics has been influenced by a new approach, soft-robotics, bringing the idea that safe interaction with user and more adaptation to the environment can be achieved by exploiting easily deformable materials and flexible components in the structure of robots. In 2016, the soft-robotics community has promoted a new robotics challenge, named RoboSoft Grand Challenge, with the aim of bringing together different opinions on the usefulness and applicability of softness and compliancy in robotics. In this paper we describe the design and implementation of a terrestrial robot based on two soft legged wheels. The tasks predefined by the challenge were set as targets in the robot design, which finally succeeded to accomplish all the tasks. The wheels of the robot can passively climb over stairs and adapt to slippery grounds using two soft legs embedded in their structure. The soft legs, fabricated by integration of soft and rigid materials and mounted on the circumference of a conventional wheel, succeed to enhance its functionality and easily adapt to unknown grounds. The robot has a semi stiff tail that helps in the stabilization and climbing of stairs. An active wheel is embedded at the extremity of the tail in order to increase the robot maneuverability in narrow environments. Moreover two parallelogram linkages let the robot to reconfigure and shrink its size allowing entering inside gates smaller than its initial dimensions.

  2. Multiple Chaotic Central Pattern Generators with Learning for Legged Locomotion and Malfunction Compensation

    DEFF Research Database (Denmark)

    Ren, Guanjiao; Chen, Weihai; Dasgupta, Sakyasingha

    2015-01-01

    on a simulated annealing algorithm. In a normal situation, the CPGs synchronize and their dynamics are identical. With leg malfunction or disability, the CPGs lose synchronization leading to independent dynamics. In this case, the learning mechanism is applied to automatically adjust the remaining legs...... chaotic CPG controller has difficulties dealing with leg malfunction. Specifically, in the scenarios presented here, its movement permanently deviates from the desired trajectory. To address this problem, we extend the single chaotic CPG to multiple CPGs with learning. The learning mechanism is based...... in a physical simulation of a quadruped as well as a hexapod robot and finally in a real six-legged walking machine called AMOSII. The experimental results presented here reveal that using multiple CPGs with learning is an effective approach for adaptive locomotion generation where, for instance, different body...

  3. On the role of sensory feedbacks in Rowat-Selverston CPG to improve robot legged locomotion

    Directory of Open Access Journals (Sweden)

    Elmira eAmrollah

    2010-12-01

    Full Text Available This paper presents the use of Rowat and Selverston-type of CPG to control locomotion. It focuses on the role of afferent exteroceptive and proprioceptive signals in the dynamic phase synchronization in CPG legged robots. The sensori-motor neural network architecture is evaluated to control a two-joint planar robot leg that slips on a rail. Then, the closed loop between the CPG and the mechanical system allows to study the modulation of rhythmic patterns and the effect of the sensing loop via sensory neurons during the locomotion task. Firstly simulations show that the proposed architecture easily allows to modulate rhythmic patterns of the leg, and therefore the velocity of the robot. Secondly, simulations show that sensori-feedbacks from foot/ground contact of the leg make the hip velocity smoother and larger. The results show that the Rowat-Selverston-type CPG with sensory feedbacks is an effective choice for building adaptive Neural Central Pattern Generators for legged robots.

  4. Genetic parameters for claw and leg health, foot and leg conformation, and locomotion in Danish Holsteins

    DEFF Research Database (Denmark)

    Laursen, M. V.; Boelling, D.; Mark, Thomas

    2009-01-01

    The purpose of this study was to estimate the genetic correlations among claw and leg health and potential indicator traits. Claw health was defined as absence of heel horn erosion, interdigital dermatitis, interdigital phlegmon, interdigital hyperplasia, laminitis, and sole ulcer. Leg health...

  5. Development and Testing of a Mobile Robot with Hybrid Legged-Wheeled Locomotion

    Directory of Open Access Journals (Sweden)

    Petre Barbu

    2017-06-01

    Full Text Available In this paper the authors present the development and testing process of a mobile robot with hybrid legged-wheeled locomotion, that can be used for exploring dangerous environments. The robot has a high adaptability to rough terrain by being able to modify its ride height, to overpass step or ditch type obstacles and most of all, being able to operate while overturned or to revert itself into the normal operating position.

  6. Dynamics of underwater legged locomotion: modeling and experiments on an octopus-inspired robot.

    Science.gov (United States)

    Calisti, M; Corucci, F; Arienti, A; Laschi, C

    2015-07-30

    This paper studies underwater legged locomotion (ULL) by means of a robotic octopus-inspired prototype and its associated model. Two different types of propulsive actions are embedded into the robot model: reaction forces due to leg contact with the ground and hydrodynamic forces such as the drag arising from the sculling motion of the legs. Dynamic parameters of the model are estimated by means of evolutionary techniques and subsequently the model is exploited to highlight some distinctive features of ULL. Specifically, the separation between the center of buoyancy (CoB)/center of mass and density affect the stability and speed of the robot, whereas the sculling movements contribute to propelling the robot even when its legs are detached from the ground. The relevance of these effects is demonstrated through robotic experiments and model simulations; moreover, by slightly changing the position of the CoB in the presence of the same feed-forward activation, a number of different behaviors (i.e. forward and backward locomotion at different speeds) are achieved.

  7. Leg-adjustment strategies for stable running in three dimensions

    International Nuclear Information System (INIS)

    Peuker, Frank; Maufroy, Christophe; Seyfarth, André

    2012-01-01

    The dynamics of the center of mass (CoM) in the sagittal plane in humans and animals during running is well described by the spring-loaded inverted pendulum (SLIP). With appropriate parameters, SLIP running patterns are stable, and these models can recover from perturbations without the need for corrective strategies, such as the application of additional forces. Rather, it is sufficient to adjust the leg to a fixed angle relative to the ground. In this work, we consider the extension of the SLIP to three dimensions (3D SLIP) and investigate feed-forward strategies for leg adjustment during the flight phase. As in the SLIP model, the leg is placed at a fixed angle. We extend the scope of possible reference axes from only fixed horizontal and vertical axes to include the CoM velocity vector as a movement-related reference, resulting in six leg-adjustment strategies. Only leg-adjustment strategies that include the CoM velocity vector produced stable running and large parameter domains of stability. The ability of the model to recover from perturbations along the direction of motion (directional stability) depended on the strategy for lateral leg adjustment. Specifically, asymptotic and neutral directional stability was observed for strategies based on the global reference axis and the velocity vector, respectively. Additional features of velocity-based leg adjustment are running at arbitrary low speed (kinetic energy) and the emergence of large domains of stable 3D running that are smoothly transferred to 2D SLIP stability and even to 1D SLIP hopping. One of the additional leg-adjustment strategies represented a large convex region of parameters where stable and robust hopping and running patterns exist. Therefore, this strategy is a promising candidate for implementation into engineering applications, such as robots, for instance. In a preliminary comparison, the model predictions were in good agreement with the experimental data, suggesting that the 3D SLIP is an

  8. Influence of “J”-Curve Spring Stiffness on Running Speeds of Segmented Legs during High-Speed Locomotion

    Directory of Open Access Journals (Sweden)

    Runxiao Wang

    2016-01-01

    Full Text Available Both the linear leg spring model and the two-segment leg model with constant spring stiffness have been broadly used as template models to investigate bouncing gaits for legged robots with compliant legs. In addition to these two models, the other stiffness leg spring models developed using inspiration from biological characteristic have the potential to improve high-speed running capacity of spring-legged robots. In this paper, we investigate the effects of “J”-curve spring stiffness inspired by biological materials on running speeds of segmented legs during high-speed locomotion. Mathematical formulation of the relationship between the virtual leg force and the virtual leg compression is established. When the SLIP model and the two-segment leg model with constant spring stiffness and with “J”-curve spring stiffness have the same dimensionless reference stiffness, the two-segment leg model with “J”-curve spring stiffness reveals that (1 both the largest tolerated range of running speeds and the tolerated maximum running speed are found and (2 at fast running speed from 25 to 40/92 m s−1 both the tolerated range of landing angle and the stability region are the largest. It is suggested that the two-segment leg model with “J”-curve spring stiffness is more advantageous for high-speed running compared with the SLIP model and with constant spring stiffness.

  9. Influence of "J"-Curve Spring Stiffness on Running Speeds of Segmented Legs during High-Speed Locomotion.

    Science.gov (United States)

    Wang, Runxiao; Zhao, Wentao; Li, Shujun; Zhang, Shunqi

    2016-01-01

    Both the linear leg spring model and the two-segment leg model with constant spring stiffness have been broadly used as template models to investigate bouncing gaits for legged robots with compliant legs. In addition to these two models, the other stiffness leg spring models developed using inspiration from biological characteristic have the potential to improve high-speed running capacity of spring-legged robots. In this paper, we investigate the effects of "J"-curve spring stiffness inspired by biological materials on running speeds of segmented legs during high-speed locomotion. Mathematical formulation of the relationship between the virtual leg force and the virtual leg compression is established. When the SLIP model and the two-segment leg model with constant spring stiffness and with "J"-curve spring stiffness have the same dimensionless reference stiffness, the two-segment leg model with "J"-curve spring stiffness reveals that (1) both the largest tolerated range of running speeds and the tolerated maximum running speed are found and (2) at fast running speed from 25 to 40/92 m s -1 both the tolerated range of landing angle and the stability region are the largest. It is suggested that the two-segment leg model with "J"-curve spring stiffness is more advantageous for high-speed running compared with the SLIP model and with constant spring stiffness.

  10. How to find home backwards? Locomotion and inter-leg coordination during rearward walking of Cataglyphis fortis desert ants.

    Science.gov (United States)

    Pfeffer, Sarah E; Wahl, Verena L; Wittlinger, Matthias

    2016-07-15

    For insects, flexibility in the performance of terrestrial locomotion is a vital part of facing the challenges of their often unpredictable environment. Arthropods such as scorpions and crustaceans can switch readily from forward to backward locomotion, but in insects this behaviour seems to be less common and, therefore, is only poorly understood. Here we present an example of spontaneous and persistent backward walking in Cataglyphis desert ants that allows us to investigate rearward locomotion within a natural context. When ants find a food item that is too large to be lifted up and to be carried in a normal forward-faced orientation, they will drag the load walking backwards to their home nest. A detailed examination of this behaviour reveals a surprising flexibility of the locomotor output. Compared with forward walks with regular tripod coordination, no main coordination pattern can be assigned to rearward walks. However, we often observed leg-pair-specific stepping patterns. The front legs frequently step with small stride lengths, while the middle and the hind legs are characterized by less numerous but larger strides. But still, these specializations show no rigidly fixed leg coupling, nor are they strictly embedded within a temporal context; therefore, they do not result in a repetitive coordination pattern. The individual legs act as separate units, most likely to better maintain stability during backward dragging. © 2016. Published by The Company of Biologists Ltd.

  11. Locomotion

    DEFF Research Database (Denmark)

    Kiehn, Ole; Dougherty, Kimberly

    2016-01-01

    Locomotion is a complex motor behavior needed by animals and humans to move through the environment. All forms of locomotion, including swimming, flying, walking, running, and hopping, are repetitive motor activities that require the activation of the limb and body muscles in an organized rhythm ...

  12. Experimental Validation of Motor Primitive-Based Control for Leg Exoskeletons during Continuous Multi-Locomotion Tasks

    Science.gov (United States)

    Ruiz Garate, Virginia; Parri, Andrea; Yan, Tingfang; Munih, Marko; Molino Lova, Raffaele; Vitiello, Nicola; Ronsse, Renaud

    2017-01-01

    An emerging approach to design locomotion assistive devices deals with reproducing desirable biological principles of human locomotion. In this paper, we present a bio-inspired controller for locomotion assistive devices based on the concept of motor primitives. The weighted combination of artificial primitives results in a set of virtual muscle stimulations. These stimulations then activate a virtual musculoskeletal model producing reference assistive torque profiles for different locomotion tasks (i.e., walking, ascending stairs, and descending stairs). The paper reports the validation of the controller through a set of experiments conducted with healthy participants. The proposed controller was tested for the first time with a unilateral leg exoskeleton assisting hip, knee, and ankle joints by delivering a fraction of the computed reference torques. Importantly, subjects performed a track involving ground-level walking, ascending stairs, and descending stairs and several transitions between these tasks. These experiments highlighted the capability of the controller to provide relevant assistive torques and to effectively handle transitions between the tasks. Subjects displayed a natural interaction with the device. Moreover, they significantly decreased the time needed to complete the track when the assistance was provided, as compared to wearing the device with no assistance. PMID:28367121

  13. A miniature surface tension-driven robot using spatially elliptical moving legs to mimic a water strider's locomotion.

    Science.gov (United States)

    Yan, J H; Zhang, X B; Zhao, J; Liu, G F; Cai, H G; Pan, Q M

    2015-08-04

    The highly agile and efficient water-surface locomotion of the water strider has stimulated substantial interest in biomimetic research. In this paper, we propose a new miniature surface tension-driven robot inspired by the water strider. A key feature of this robot is that its actuating leg possesses an ellipse-like spatial trajectory similar to that of a water strider by using a cam-link mechanism. Simplified models are presented to discuss the leg-water interactions as well as critical conditions for a leg penetrating the water surface, and simulations are performed on the robot's dynamic properties. The final fabricated robot weighs about 3.9 g, and can freely and stably walk on water at different gaits. The maximum forward and turning speeds of the robot are measured as 16 cm s(-1) and 23°/s, respectively. Furthermore, a similarity analysis with Bond number and Weber number demonstrates that the locomotion of this robot is quite analogous to that of a real water strider: the surface tension force dominates the lifting force and plays a major role in the propulsion force. This miniature surface tension-driven robot might have potential applications in many areas such as water quality monitoring and aquatic search and rescue.

  14. A survey report for the design of biped locomotion robot: the WL-12 (Waseda Leg-12)

    Energy Technology Data Exchange (ETDEWEB)

    Takanishi, Atsuo; Kato, Ichiro [Waseda Univ., Tokyo (Japan); Kume, Etsuo

    1991-11-01

    A mechanical design study of biped locomotion robots is going on at JAERI within the scope of the Human Acts Simulation Program (HASP). The design study at JAERI is of an arbitrarily mobile robot for inspection of nuclear facilities. A survey has been performed for collecting useful information from already existing biped locomotion robots. This is a survey report of the biped locomotion robot: the WL-12 designed and developed at Waseda University. This report includes the mechanical model and control system designs. (author).

  15. Minimizing the cost of locomotion with inclined trunk predicts crouched leg kinematics of small birds at realistic levels of elastic recoil.

    Science.gov (United States)

    Rode, Christian; Sutedja, Yefta; Kilbourne, Brandon M; Blickhan, Reinhard; Andrada, Emanuel

    2016-02-01

    Small birds move with pronograde trunk orientation and crouched legs. Although the pronograde trunk has been suggested to be beneficial for grounded running, the cause(s) of the specific leg kinematics are unknown. Here we show that three charadriiform bird species (northern lapwing, oystercatcher, and avocet; great examples of closely related species that differ remarkably in their hind limb design) move their leg segments during stance in a way that minimizes the cost of locomotion. We imposed measured trunk motions and ground reaction forces on a kinematic model of the birds. The model was used to search for leg configurations that minimize leg work that accounts for two factors: elastic recoil in the intertarsal joint, and cheaper negative muscle work relative to positive muscle work. A physiological level of elasticity (∼ 0.6) yielded segment motions that match the experimental data best, with a root mean square of angular deviations of ∼ 2.1 deg. This finding suggests that the exploitation of elastic recoil shapes the crouched leg kinematics of small birds under the constraint of pronograde trunk motion. Considering that an upright trunk and more extended legs likely decrease the cost of locomotion, our results imply that the cost of locomotion is a secondary movement criterion for small birds. Scaling arguments suggest that our approach may be utilized to provide new insights into the motion of extinct species such as dinosaurs. © 2016. Published by The Company of Biologists Ltd.

  16. Common mechanics of mode switching in locomotion of limbless and legged animals

    Science.gov (United States)

    Kuroda, Shigeru; Kunita, Itsuki; Tanaka, Yoshimi; Ishiguro, Akio; Kobayashi, Ryo; Nakagaki, Toshiyuki

    2014-01-01

    Crawling using muscular waves is observed in many species, including planaria, leeches, nemertea, aplysia, snails, chitons, earthworms and maggots. Contraction or extension waves propagate along the antero-posterior axis of the body as the crawler pushes the ground substratum backward. However, the observation that locomotory waves can be directed forward or backward has attracted much attention over the past hundred years. Legged organisms such as centipedes and millipedes exhibit parallel phenomena; leg tips form density waves that propagate backward or forward. Mechanical considerations reveal that leg-density waves play a similar role to locomotory waves in limbless species, and that locomotory waves are used by a mechanism common to both legged and limbless species to achieve crawling. Here, we report that both mode switching of the wave direction and friction control were achieved when backward motion was induced in the laboratory. We show that the many variations of switching in different animals can essentially be classified in two types according to mechanical considerations. We propose that during their evolution, limbless crawlers first moved in a manner similar to walking before legs were obtained. Therefore, legged crawlers might have learned the mechanical mode of movement involved in walking long before obtaining legs. PMID:24718452

  17. Closed-loop control of trunk posture improves locomotion through the regulation of leg proprioceptive feedback after spinal cord injury.

    Science.gov (United States)

    Moraud, Eduardo Martin; von Zitzewitz, Joachim; Miehlbradt, Jenifer; Wurth, Sophie; Formento, Emanuele; DiGiovanna, Jack; Capogrosso, Marco; Courtine, Grégoire; Micera, Silvestro

    2018-01-08

    After spinal cord injury (SCI), sensory feedback circuits critically contribute to leg motor execution. Compelled by the importance to engage these circuits during gait rehabilitation, assistive robotics and training protocols have primarily focused on guiding leg movements to reinforce sensory feedback. Despite the importance of trunk postural dynamics on gait and balance, trunk assistance has comparatively received little attention. Typically, trunk movements are either constrained within bodyweight support systems, or manually adjusted by therapists. Here, we show that real-time control of trunk posture re-established dynamic balance amongst bilateral proprioceptive feedback circuits, and thereby restored left-right symmetry, loading and stepping consistency in rats with severe SCI. We developed a robotic system that adjusts mediolateral trunk posture during locomotion. This system uncovered robust relationships between trunk orientation and the modulation of bilateral leg kinematics and muscle activity. Computer simulations suggested that these modulations emerged from corrections in the balance between flexor- and extensor-related proprioceptive feedback. We leveraged this knowledge to engineer control policies that regulate trunk orientation and postural sway in real-time. This dynamical postural interface immediately improved stepping quality in all rats regardless of broad differences in deficits. These results emphasize the importance of trunk regulation to optimize performance during rehabilitation.

  18. Kinetics evaluation of using biomimetic IPMC actuators for stable bipedal locomotion

    Science.gov (United States)

    Hosseinipour, M.; Elahinia, M.

    2013-04-01

    Ionic conducting polymer-metal composites (IPMC) are flexible actuators that can act as artificial muscles in many robotic and microelectromechanical systems. The authors have already investigated the possibility of kinematically stable bipedal locomotion using these actuators. Fabrication parameters of actuators including minimum lengths, installation angles, plating thicknesses and maximum required voltages were found in previous studies for a stable bipedal gait with maximum speed of 0.1093 m/s. Extending the FEA solution of the governing partial differential equation of the behavior of IPMCs to 2D, actuator limits were found. Considering these limits, joint path trajectories were generated to achieve a fast and smooth motion on a seven-degree of freedom biped robot. This study utilizes the same biped model, and focuses on the kinetics of the proposed gait in order to complement the evaluation of using IPMCs as biomimetic actuators for bipedal locomotion. The dynamic equations of motion of the previously designed bipedal gait are solved here to find the maximum required joint torques. Blocking force of a flap of IPMC is found by plugging results of the FEA into a model based on beam theories. This force adequately predicts the maximum deliverable torque of a piece of IPMC with certain length. Feasibility of using IPMCs as joint actuators is then evaluated by comparing the required and achievable torques. This study concludes the previous work to cover feasibility, stability and design of a biped robot actuated with IPMC flaps.

  19. Kinematically stable bipedal locomotion using ionic polymer-metal composite actuators

    Science.gov (United States)

    Hosseinipour, Milad; Elahinia, Mohammad

    2013-08-01

    Ionic conducting polymer-metal composites (abbreviated as IPMCs) are interesting actuators that can act as artificial muscles in robotic and microelectromechanical systems. Various black or gray box models have modeled the electrochemical-mechanical behavior of these materials. In this study, the governing partial differential equation of the behavior of IPMCs is solved using finite element methods to find the critical actuation parameters, such as strain distribution, maximum strain, and response time. One-dimensional results of the FEM solution are then extended to 2D to find the tip displacement of a flap actuator and experimentally verified. A model of a seven-degree-of-freedom biped robot, actuated by IPMC flaps, is then introduced. The possibility of fast and stable bipedal locomotion using IPMC artificial muscles is the main motivation of this study. Considering the actuator limits, joint path trajectories are generated to achieve a fast and smooth motion. The stability of the proposed gait is then evaluated using the ZMP criterion and motion simulation. The fabrication parameters of each actuator, such as length, platinum plating thickness and installation angle, are then determined using the generated trajectories. A discussion on future studies on force-torque generation of IPMCs for biped locomotion concludes this paper.

  20. Acquiring Efficient Locomotion in a Simulated Quadruped through Evolving Random and Predefined Neural Networks

    DEFF Research Database (Denmark)

    Veenstra, Frank; Struck, Alexander; Krauledat, Matthias

    2015-01-01

    The acquisition and optimization of dynamically stable locomotion is important to engender fast and energy efficient locomotion in animals. Conventional optimization strategies tend to have difficulties in acquiring dynamically stable gaits in legged robots. In this paper, an evolving neural...... network (ENN) was implemented with the aim to optimize the locomotive behavior of a four-legged simulated robot. In the initial generation, individuals had neural networks (NNs) that were either predefined or randomly initialized. Additional investigations show that the efficiency of applying additional...... optimize a locomotive strategy for a simulated quadruped....

  1. Successive substitution one-leg hybrid P-stable LMM for initial value ...

    African Journals Online (AJOL)

    This paper derives P-stable successive substitution one-leg hybrid linear multistep methods for the numerical solution of second order initial value problems in ordinary differential equations without explicit first order derivative. The methods are demonstrated by a numerical example also considered by Fatunla, et al (1997) ...

  2. One Leg hybrid P-stable substitution LMM for oscilatory IVPs in ODEs.

    African Journals Online (AJOL)

    This presents P-stable successive substitution one-leg hybrid LMM for the numerical solution of oscillatory second order IVPs in ODEs without explicitly defined first order derivative. These problems occurs amongst others, in orbital mechanics where the methods to be presented finds ready applications and need not any a ...

  3. Mechanics of a rapid running insect: two-, four- and six-legged locomotion.

    Science.gov (United States)

    Full, R J; Tu, M S

    1991-03-01

    To examine the effects of variation in body form on the mechanics of terrestrial locomotion, we used a miniature force platform to measure the ground reaction forces of the smallest and, relative to its mass, one of the fastest invertebrates ever studied, the American cockroach Periplaneta americana (mass = 0.83 g). From 0.44-1.0 ms-1, P. americana used an alternating tripod stepping pattern. Fluctuations in gravitational potential energy and horizontal kinetic energy of the center of mass were nearly in phase, characteristic of a running or bouncing gait. Aerial phases were observed as vertical ground reaction force approached zero at speeds above 1 ms-1. At the highest speeds (1.0-1.5 ms-1 or 50 body lengths per second), P. americana switched to quadrupedal and bipedal running. Stride frequency approached the wing beat frequencies used during flight (27 Hz). High speeds were attained by increasing stride length, whereas stride frequency showed little increase with speed. The mechanical power used to accelerate the center of mass increased curvilinearly with speed. The mass-specific mechanical energy used to move the center of mass a given distance was similar to that measured for animals five orders of magnitude larger in mass, but was only one-hundredth of the metabolic cost.

  4. Large-scale association study for structural soundness and leg locomotion traits in the pig

    Directory of Open Access Journals (Sweden)

    Serenius Timo

    2009-01-01

    Full Text Available Abstract Background Identification and culling of replacement gilts with poor skeletal conformation and feet and leg (FL unsoundness is an approach used to reduce sow culling and mortality rates in breeding stock. Few candidate genes related to soundness traits have been identified in the pig. Methods In this study, 2066 commercial females were scored for 17 traits describing body conformation and FL structure, and were used for association analyses. Genotyping of 121 SNPs derived from 95 genes was implemented using Sequenom's MassARRAY system. Results Based on the association results from single trait and principal components using mixed linear model analyses and false discovery rate testing, it was observed that APOE, BMP8, CALCR, COL1A2, COL9A1, DKFZ, FBN1 and VDBP were very highly significantly (P ALOX5, BMP8, CALCR, OPG, OXTR and WNT16 were very highly significantly (P APOE, CALCR, COL1A2, GNRHR, IHH, MTHFR and WNT16 were highly significantly (P CALCR and COL1A2 on SSC9 was detected, and haplotype -ACGACC- was highly significantly (P Conclusion The present findings provide a comprehensive list of candidate genes for further use in fine mapping and biological functional analyses.

  5. Kinematic primitives for walking and trotting gaits of a quadruped robot with compliant legs.

    Science.gov (United States)

    Spröwitz, Alexander T; Ajallooeian, Mostafa; Tuleu, Alexandre; Ijspeert, Auke Jan

    2014-01-01

    In this work we research the role of body dynamics in the complexity of kinematic patterns in a quadruped robot with compliant legs. Two gait patterns, lateral sequence walk and trot, along with leg length control patterns of different complexity were implemented in a modular, feed-forward locomotion controller. The controller was tested on a small, quadruped robot with compliant, segmented leg design, and led to self-stable and self-stabilizing robot locomotion. In-air stepping and on-ground locomotion leg kinematics were recorded, and the number and shapes of motion primitives accounting for 95% of the variance of kinematic leg data were extracted. This revealed that kinematic patterns resulting from feed-forward control had a lower complexity (in-air stepping, 2-3 primitives) than kinematic patterns from on-ground locomotion (νm4 primitives), although both experiments applied identical motor patterns. The complexity of on-ground kinematic patterns had increased, through ground contact and mechanical entrainment. The complexity of observed kinematic on-ground data matches those reported from level-ground locomotion data of legged animals. Results indicate that a very low complexity of modular, rhythmic, feed-forward motor control is sufficient for level-ground locomotion in combination with passive compliant legged hardware.

  6. Kinematic primitives for a quadruped robot walk and trot with compliant legs

    Directory of Open Access Journals (Sweden)

    Alexander Thomas Sprowitz

    2014-03-01

    Full Text Available In this work we research the role of body dynamics in the complexity of kinematic patterns in a quadruped robot with compliant legs. Two gait patterns, lateral sequence walk and trot, along with leg length control patterns of different complexity were implemented in a modular, feed-forward locomotion controller. The controller was tested on a small, quadruped robot with compliant, segmented leg design, and led to self-stable and self-stabilizing robot locomotion. In-air stepping and on-ground locomotion leg kinematics were recorded, and the number and shapes of motion primitives accounting for 95% of the variance of kinematic leg data were extracted. This revealed that kinematic patterns resulting from feed-forward control had a lower complexity (in-air stepping, 2 to 3 primitives than kinematic patterns from on-ground locomotion (4 primitives, although both experiments applied identical motor patterns. The complexity of on-ground kinematic patterns had increased, through ground contact and mechanical entrainment. The complexity of observed kinematic on-ground data matches those reported from level-ground locomotion data of legged animals. Results indicate that a very low complexity of modular, rhythmic, feed-forward motor control is sufficient for level-ground locomotion in combination with passive compliant legged hardware.

  7. Association between Lameness and Indicators of Dairy Cow Welfare Based on Locomotion Scoring, Body and Hock Condition, Leg Hygiene and Lying Behavior

    Science.gov (United States)

    Ramanoon, Siti Z.; Shaik Mossadeq, Wan Mastura; Mansor, Rozaihan; Syed-Hussain, Sharifah Salmah

    2017-01-01

    Simple Summary Lameness is a major welfare issue in dairy cows. Locomotion scoring (LS) is mostly used in identifying lame cows based on gait and postural changes. However, lameness shares some important associations with body condition, hock condition, leg hygiene and behavioral changes such as lying behavior. These measures are considered animal-based indicators in assessing welfare in dairy cows. This review discusses lameness as a welfare problem, the use of LS, and the relationship with the aforementioned welfare assessment protocols. Such information could be useful in depicting the impact on cow welfare as well as in reducing the occurrence of lameness in dairy herds. Abstract Dairy cow welfare is an important consideration for optimal production in the dairy industry. Lameness affects the welfare of dairy herds by limiting productivity. Whilst the application of LS systems helps in identifying lame cows, the technique meets with certain constraints, ranging from the detection of mild gait changes to on-farm practical applications. Recent studies have shown that certain animal-based measures considered in welfare assessment, such as body condition, hock condition and leg hygiene, are associated with lameness in dairy cows. Furthermore, behavioural changes inherent in lame cows, especially the comfort in resting and lying down, have been shown to be vital indicators of cow welfare. Highlighting the relationship between lameness and these welfare indicators could assist in better understanding their role, either as risk factors or as consequences of lameness. Nevertheless, since the conditions predisposing a cow to lameness are multifaceted, it is vital to cite the factors that could influence the on-farm practical application of such welfare indicators in lameness studies. This review begins with the welfare consequences of lameness by comparing normal and abnormal gait as well as the use of LS system in detecting lame cows. Animal-based measures related to

  8. Neuromusculoskeletal computer modeling and simulation of upright, straight-legged, bipedal locomotion of Australopithecus afarensis (A.L. 288-1).

    Science.gov (United States)

    Nagano, Akinori; Umberger, Brian R; Marzke, Mary W; Gerritsen, Karin G M

    2005-01-01

    The skeleton of Australopithecus afarensis (A.L. 288-1, better known as "Lucy") is by far the most complete record of locomotor morphology of early hominids currently available. Even though researchers agree that the postcranial skeleton of Lucy shows morphological features indicative of bipedality, only a few studies have investigated Lucy's bipedal locomotion itself. Lucy's energy expenditure during locomotion has been the topic of much speculation, but has not been investigated, except for several estimates derived from experimental data collected on other animals. To gain further insights into how Lucy may have walked, we generated a full three-dimensional (3D) reconstruction and forward-dynamic simulation of upright bipedal locomotion of this ancient human ancestor. Laser-scanned 3D bone geometries were combined with state-of-the-art neuromusculoskeletal modeling and simulation techniques from computational biomechanics. A detailed full 3D neuromusculoskeletal model was developed that encompassed all major bones, joints (10), and muscles (52) of the lower extremity. A model of muscle force and heat production was used to actuate the musculoskeletal system, and to estimate total energy expenditure during locomotion. Neural activation profiles for each of the 52 muscles that produced a single step of locomotion, while at the same time minimizing the energy consumed per meter traveled, were searched through numerical optimization. The numerical optimization resulted in smooth locomotor kinematics, and the predicted energy expenditure was appropriate for upright bipedal walking in an individual of Lucy's body size. (c) 2004 Wiley-Liss, Inc.

  9. Biomonitoring of coastal areas in Tunisia: Stable isotope and trace element analysis in the Yellow-legged Gull

    International Nuclear Information System (INIS)

    Abdennadher, Aida; Ramirez, Francisco; Romdhane, Mohamed Salah; Ruiz, Xavier; Jover, Lluis; Sanpera, Carolina

    2010-01-01

    We used Yellow-legged Gull (YLG) chicks to monitor trace elements in Tunisian areas subject to different pollution stresses: urban contamination (Chikly), industrial pollution (Thyna) and an unpolluted area (Kneis). We measured trace element concentrations (Hg, Se and Pb) in chick feathers. We also assessed their feeding ecology by analyzing both regurgitates and stable isotopes (SIA) in chick feathers and in their prey, to determine the main entry route of pollutants. SIA revealed that YLG feed mainly on aquatic resources from the Lake of Tunis (Chikly colony) and the Gulf of Gabes (Thyna and Kneis colonies). Moreover, the enriched δ 15 N found in feathers from Chikly are attributed to the eutrophication of the Lake of Tunis. Hg and Se were higher in Kneis and Thyna colonies, in agreement with the higher consumption of marine resources and the greater availability of these elements resulting from the impact of the industrial activity in the area. Pb concentrations were higher in Chikly, related to the heavier traffic around the Lake of Tunis and the use of leaded gasoline.

  10. Compensations during Unsteady Locomotion.

    Science.gov (United States)

    Qiao, Mu; Jindrich, Devin L

    2014-12-01

    Locomotion in a complex environment is often not steady, but the mechanisms used by animals to power and control unsteady locomotion (stability and maneuverability) are not well understood. We use behavioral, morphological, and impulsive perturbations to determine the compensations used during unsteady locomotion. At the level both of the whole-body and of joints, quasi-stiffness models are useful for describing adjustments to the functioning of legs and joints during maneuvers. However, alterations to the mechanics of legs and joints often are distinct for different phases of the step cycle or for specific joints. For example, negotiating steps involves independent changes of leg stiffness during compression and thrust phases of stance. Unsteady locomotion also involves parameters that are not part of the simplest reduced-parameter models of locomotion (e.g., the spring-loaded inverted pendulum) such as moments of the hip joint. Extensive coupling among translational and rotational parameters must be taken into account to stabilize locomotion or maneuver. For example, maneuvers with morphological perturbations (increased rotational inertial turns) involve changes to several aspects of movement, including the initial conditions of rotation and ground-reaction forces. Coupled changes to several parameters may be employed to control maneuvers on a trial-by-trial basis. Compensating for increased rotational inertia of the body during turns is facilitated by the opposing effects of several mechanical and behavioral parameters. However, the specific rules used by animals to control translation and rotation of the body to maintain stability or maneuver have not been fully characterized. We initiated direct-perturbation experiments to investigate the strategies used by humans to maintain stability following center-of-mass (COM) perturbations. When walking, humans showed more resistance to medio-lateral perturbations (lower COM displacement). However, when running, humans

  11. Omnidirectional Wheel-Legged Hybrid Mobile Robot

    Directory of Open Access Journals (Sweden)

    István Vilikó

    2015-06-01

    Full Text Available The purpose of developing hybrid locomotion systems is to merge the advantages and to eliminate the disadvantages of different type of locomotion. The proposed solution combines wheeled and legged locomotion methods. This paper presents the mechatronic design approach and the development stages of the prototype.

  12. Biped locomotion control with compliance; Compliance wo mochiita nisoku soko robot no undo seigyo

    Energy Technology Data Exchange (ETDEWEB)

    Kawaji, S.; Ogasawara, K.; Iimori, J. [Kumamoto University, Kumamoto (Japan)

    1995-12-20

    Realization of stable walking motion of biped locomotive robot is one of difficult control problems, but it is very interesting both theoretically and practically from the view point of motion control. The authors have already reported that the locomotion rhythm plays an important role in walking motions, and confirmed experimentally that the control method based on the locomotion rhythm is effective. But, many uncertainties, e.g., the changes of robot dynamics and the interaction between the robot and the floor, may make the locomotion rhythm irregular. In this paper, we introduce the compliance into the control system in order to modify the original reference locomotion rhythm for stable walking under the existence of the uncertainties. Concretely a compliance control system for the contact leg is designed to modify the rhythm by changing the posture of the leg corresponding to the force acting from the body so that the robot may keep the equilibrium state dynamically. Finally the simulation results are given to illustrate the effectiveness of the proposed compliance control system. 21 refs., 12 figs., 3 tabs.

  13. Running over unknown rough terrain with a one-legged planar robot

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, Ben; Miller, Bruce; Clark, Jonathan E [Department of Mechanical Engineering, Florida State University, Tallahassee, FL 32310 (United States); Schmitt, John, E-mail: clarkj@eng.fsu.edu [Department of Mechanical Engineering, Oregon State University, Corvallis, OR 97331 (United States)

    2011-06-15

    The ability to traverse unknown, rough terrain is an advantage that legged locomoters have over their wheeled counterparts. However, due to the complexity of multi-legged systems, research in legged robotics has not yet been able to reproduce the agility found in the animal kingdom. In an effort to reduce the complexity of the problem, researchers have developed single-legged models to gain insight into the fundamental dynamics of legged running. Inspired by studies of animal locomotion, researchers have proposed numerous control strategies to achieve stable, one-legged running over unknown, rough terrain. One such control strategy incorporates energy variations into the system during the stance phase by changing the force-free leg length as a sinusoidal function of time. In this research, a one-legged planar robot capable of implementing this and other state-of-the-art control strategies was designed and built. Both simulated and experimental results were used to determine and compare the stability of the proposed controllers as the robot was subjected to unknown drop and raised step perturbations equal to 25% of the nominal leg length. This study illustrates the relative advantages of utilizing a minimal-sensing, active energy removal control scheme to stabilize running over rough terrain.

  14. Running over unknown rough terrain with a one-legged planar robot

    International Nuclear Information System (INIS)

    Andrews, Ben; Miller, Bruce; Clark, Jonathan E; Schmitt, John

    2011-01-01

    The ability to traverse unknown, rough terrain is an advantage that legged locomoters have over their wheeled counterparts. However, due to the complexity of multi-legged systems, research in legged robotics has not yet been able to reproduce the agility found in the animal kingdom. In an effort to reduce the complexity of the problem, researchers have developed single-legged models to gain insight into the fundamental dynamics of legged running. Inspired by studies of animal locomotion, researchers have proposed numerous control strategies to achieve stable, one-legged running over unknown, rough terrain. One such control strategy incorporates energy variations into the system during the stance phase by changing the force-free leg length as a sinusoidal function of time. In this research, a one-legged planar robot capable of implementing this and other state-of-the-art control strategies was designed and built. Both simulated and experimental results were used to determine and compare the stability of the proposed controllers as the robot was subjected to unknown drop and raised step perturbations equal to 25% of the nominal leg length. This study illustrates the relative advantages of utilizing a minimal-sensing, active energy removal control scheme to stabilize running over rough terrain.

  15. Energy Efficiency of Robot Locomotion Increases Proportional to Weight

    DEFF Research Database (Denmark)

    Larsen, Jørgen Christian; Støy, Kasper

    2011-01-01

    The task of producing steady, stable and energy efficient locomotion in legged robots with the ability to walk in un- known terrain have for many years been a big challenge in robotics. This work is focusing on how different robots build from the modular robotic system, LocoKit by Larsen et. la [3......], performs compared to animals, and also on the similari- ties between robots an animals. This work shows, that there in robots exist the same connection between cost of trans- port and the weight of the robots as is true for animals....

  16. Energy Efficiency of Robot Locomotion Increases Proportional to Weight

    DEFF Research Database (Denmark)

    Larsen, J. C.; Stoy, K.

    2011-01-01

    The task of producing steady, stable and energy efficient locomotion in legged robots with the ability to walk in unknown terrain have for many years been a big challenge in robotics. This work is focusing on how different robots build from the modular robotic system, LocoKit by Larsen et al. [1......], performs compared to animals, and also on the similarities between robots an animals. This work shows, that there in robots exist the same connection between cost of transport and the weight of the robots as is true for animals. (C) Selection and peer-review under responsibility of FET11 conference...

  17. Advanced robot locomotion.

    Energy Technology Data Exchange (ETDEWEB)

    Neely, Jason C.; Sturgis, Beverly Rainwater; Byrne, Raymond Harry; Feddema, John Todd; Spletzer, Barry Louis; Rose, Scott E.; Novick, David Keith; Wilson, David Gerald; Buerger, Stephen P.

    2007-01-01

    This report contains the results of a research effort on advanced robot locomotion. The majority of this work focuses on walking robots. Walking robot applications include delivery of special payloads to unique locations that require human locomotion to exo-skeleton human assistance applications. A walking robot could step over obstacles and move through narrow openings that a wheeled or tracked vehicle could not overcome. It could pick up and manipulate objects in ways that a standard robot gripper could not. Most importantly, a walking robot would be able to rapidly perform these tasks through an intuitive user interface that mimics natural human motion. The largest obstacle arises in emulating stability and balance control naturally present in humans but needed for bipedal locomotion in a robot. A tracked robot is bulky and limited, but a wide wheel base assures passive stability. Human bipedal motion is so common that it is taken for granted, but bipedal motion requires active balance and stability control for which the analysis is non-trivial. This report contains an extensive literature study on the state-of-the-art of legged robotics, and it additionally provides the analysis, simulation, and hardware verification of two variants of a proto-type leg design.

  18. Embodied Sensorimotor Interaction for Hexapod Locomotion

    DEFF Research Database (Denmark)

    Ambe, Yuichi; Aoi, Shinya; Nachstedt, Timo

    2016-01-01

    is still unclear. Recent studies in biology suggest that a functional motor output during walking is formed by the interaction between central pattern generators (CPGs) and sensory feedbacks. In this paper, we investigate the dynamics of a hexapod robot model whose legs are driven by distributed...... oscillators with a local sensory feedback from neuromechanical point of view. This feedback changes the oscillation period of the oscillator depending solely on the timing of the contact between the foot and the ground. The results of dynamic simulations and real robot experiments show that due to the local...... sensory feedback the robot produces continuous stable gaits depending on the locomotion speed as a result of self-organization, one of which are similar to those of insects. These results reveal that the neuromechanical interaction induced by the local sensory feedback plays an important role...

  19. Venogram - leg

    Science.gov (United States)

    Phlebogram - leg; Venography - leg; Angiogram - leg ... into a vein in the foot of the leg being looked at. An intravenous (IV) line is ... vein. A tourniquet may be placed on your leg so the dye flows into the deeper veins. ...

  20. LocoKit - A Construction Kit for Exploration of Morphology of Legged Robots

    DEFF Research Database (Denmark)

    Larsen, Jørgen Christian; Støy, Kasper

    2011-01-01

    Producing steady stable and energy efficient locomotion in legged robots with the ability to walk in unknown terrain is a big challenge in robotics. In addressing this challenge, it is often desirable to experiment with different morphologies and see how they influence on the way the robot walks...... legged robots. This is accomplished by giving the creator the possibility to easily do morphological changes to the robot even after it have been build, to see how it effects the robot?s ability to walk in unknown terrain....

  1. A new anthropometric phantom of the human leg for calibrating in vivo measurements of stable lead in bone using x-ray fluorescence

    International Nuclear Information System (INIS)

    Spitz, Henry; Jenkins, Mark; Lodwick, Jeffrey

    1997-01-01

    Full text. A new anthropometric phantom of the human leg has been developed for calibrating in vivo measurements of stable lead in the bone using x-ray fluorescence. The phantom reproduces the shape and radiological characteristics of the midshaft of the human leg and includes tissue substitutes for cortical bone, bone marrow, and muscle which have been formulated using polyurethanes and calcium carbonate to provide the desired characteristics of density x-ray attenuation, and calcium content. The phantom includes a set of simulated tibia bones, each containing a precisely known concentration of stable lead, that can be easily inserted into the leg. Formerly, of a set of plexiglas cylinders filled with plaster of-paris, each containing a known lead content, was the consensus standard calibration phantom. Tissue substitute materials used in the new anthropometric calibration phantom are much more uniform in density and composition than the plaster-of-paris phantoms and its realistic appearance provides a practical means of evaluating the variability in measurements results due to the changes in subject-detector positioning. Use of the new anthropometric calibration phantom results in a energy spectrum that closely resembles the spectrum observed when measuring a human subject. The energy spectrum produced by the plaster-of-paris phantom lacks the substantial Compton Scattering component produced by the leg muscle mass which leads to unrealistic estimates of in vivo measurement sensitivity. The minimum detection limit (MDL) for in vivo measurement of stable lead in bone, using an efficiency derived from the new anthropometric phantom, ranges from 18,6 parts per million (ppm) to 26,3 ppm using the K β1,3 /Elastic ratio or the K 1 /Elastic ratio, respectively. These values are significantly greater than the MDL cited in the literature obtained using a efficiency derived the conventional cylindrical plaster-of-paris phantom. Likewise, the realistic shape of the new

  2. Analysis of Hexapod Robot Locomotion

    Directory of Open Access Journals (Sweden)

    Tomas Luneckas

    2011-03-01

    Full Text Available Hexapod robot locomotion is analyzed. Trajectory forming method for one leg is introduced. Servo angles are expressed using geometric inverse kinematics method. Forming of tripod gait is described and a diagram representing it is presented. Servo control parameters are defined to ensure fluent and versatile robot control. Several servo control methods are presented. After testing robot movement using different servo control methods, gait generation is corrected and control method that meets servo control parameters is chosen.Article in Lithuanian

  3. Development of Underwater Microrobot with Biomimetic Locomotion

    Directory of Open Access Journals (Sweden)

    W. Zhang

    2006-01-01

    Full Text Available Microrobots have powerful applications in biomedical and naval fields. They should have a compact structure, be easy to manufacture, have efficient locomotion, be driven by low voltage and have a simple control system. To meet these purposes, inspired by the leg of stick insects, we designed a novel type of microrobot with biomimetic locomotion with 1-DOF (degree of freedom legs. The locomotion includes two ionic conducting polymer film (ICPF actuators to realize the 2-DOF motion. We developed several microrobots with this locomotion. Firstly, we review a microrobot, named Walker-1, with 1-DOF motion. And then a new microrobot, named Walker-2, utilizing six ICPF actuators, with 3-DOF motion is introduced. It is 47 mm in diameter and 8 mm in height (in static state. It has 0.61 g of dried weight. We compared the two microrobot prototypes, and the result shows that Walker-2 has some advantages, such as more flexible moving motion, good balance, less water resistance, more load-carrying ability and so on. We also compared it with some insect-inspired microrobots and some microrobots with 1-DOF legs, and the result shows that a microrobot with this novel type of locomotion has some advantages. Its structure has fewer actuators and joints, a simpler control system and is compact. The ICPF actuator decides that it can be driven by low voltage (less than 5 V and move in water. A microrobot with this locomotion has powerful applications in biomedical and naval fields.

  4. Reduction and identification for hybrid dynamical models of terrestrial locomotion

    Science.gov (United States)

    Burden, Samuel A.; Sastry, S. Shankar

    2013-06-01

    The study of terrestrial locomotion has compelling applications ranging from design of legged robots to development of novel prosthetic devices. From a first-principles perspective, the dynamics of legged locomotion seem overwhelmingly complex as nonlinear rigid body dynamics couple to a granular substrate through viscoelastic limbs. However, a surfeit of empirical data demonstrates that animals use a small fraction of their available degrees-of-freedom during locomotion on regular terrain, suggesting that a reduced-order model can accurately describe the dynamical variation observed during steady-state locomotion. Exploiting this emergent phenomena has the potential to dramatically simplify design and control of micro-scale legged robots. We propose a paradigm for studying dynamic terrestrial locomotion using empirically-validated reduced{order models.

  5. Continuum limbed robots for locomotion

    Science.gov (United States)

    Mutlu, Alper

    This thesis focuses on continuum robots based on pneumatic muscle technology. We introduce a novel approach to use these muscles as limbs of lightweight legged robots. The flexibility of the continuum legs of these robots offers the potential to perform some duties that are not possible with classical rigid-link robots. Potential applications are as space robots in low gravity, and as cave explorer robots. The thesis covers the fabrication process of continuum pneumatic muscles and limbs. It also provides some new experimental data on this technology. Afterwards, the designs of two different novel continuum robots - one tripod, one quadruped - are introduced. Experimental data from tests using the robots is provided. The experimental results are the first published example of locomotion with tripod and quadruped continuum legged robots. Finally, discussion of the results and how far this technology can go forward is presented.

  6. Artificial locomotion control

    DEFF Research Database (Denmark)

    Azevedo, Christine; Poignet, Philippe; Espiau, Bernard

    2004-01-01

    This paper concerns the simultaneous synthesis and control of walking gaits for biped robots. The goal is to propose an adaptable and reactive control law for two-legged machines. The problem is addressed with human locomotion as a reference. The starting point of our work is an analysis of human...... walking from descriptive (biomechanics) as well as explicative (neuroscience and physiology) points of view, the objective being to stress the relevant elements for the approach of robot control. The adopted principles are then: no joint trajectory tracking; explicit distinction and integration...... of postural and walking control; use of evolutive optimization objectives; on-line event handling and environment adaptation and anticipation. This leads to the synthesis of an original control scheme based on non-linear model predictive control: Trajectory Free NMPC. The movement is specified implicitly...

  7. Locomotion through Morphosis

    DEFF Research Database (Denmark)

    Larsen, Jørgen Christian

    construction kit called LocoKit, which is intended as a system on which studies on locomotion can be done in a simple way. The simplicity is ob- tained by giving the user the opportunity to build legged robots from a set of small components which allows for adjusting various parameters on the robot, even after...... in nature can be found and tested. These results shows the poten- tial of LocoKit and are nicely in line with the goal of the project. I future development, LocoKit will be improved in such a way that it allows the user to build even more efficient robots than have been build until now....

  8. Depth Dependant Variations in Benthic Foraminiferal Assemblages and Stable Isotopes Across the P-E Boundary, Walvis Ridge (ODP Leg 208)

    Science.gov (United States)

    McCarren, H. K.; Thomas, E.; Zachos, J.

    2004-12-01

    The Paleocene-Eocene Thermal Maximum (PETM) ( ˜55 Ma), was characterized by extreme global warming, a negative carbon isotope excursion, intensified carbonate dissolution, and a severe mass extinction of benthic foraminifera. The lack of continuous, undisturbed cores over a wide depth range has limited efforts to place constraints on key aspects of the PETM event, such as changes in ocean redox and carbon chemistry, and depth dependent patterns of the benthic extinction. The P-E boundary was recovered in multiple holes at 5 sites from Walvis Ridge in the southeastern Atlantic (ODP Leg 208). We document changes in benthic assemblages and stable isotopes across the PETM at ODP Leg 208, and compare these with data from other PE boundary sections, including DSDP Sites 525 and 527 previously drilled on Walvis Ridge. Faunal assemblage analyses show a distinct drop in diversity coincident with the base of the clay layer at all sites. There is a clear relationship between water depth and magnitude of the benthic foraminifera isotope excursion along the Walvis Ridge depth transect. Site 1263 (2717m) records excursion values of -2.2 δ 13C and -2.5 δ 18O; whereas Site 1262 (4759m) has values of -0.2 δ 13C and -0.8 δ 18O at the height of the excursion. This difference implies truncation of the record at deeper sites by carbonate dissolution, possibly as well as a depth dependent difference in water mass chemistry and temperature during the PETM. Several benthic foraminiferal species such as Nuttallides truempyi and various abyssaminid species that may indicate low nutrient availability increase in abundance at the onset of the isotope excursion, while the percentage of biserial and triserial species, used as high food/low oxygen indicators, decreases. There are thus distinct changes in ocean chemistry over the 2.3 km paleodepth range of the Walvis Ridge transect during the PETM event.

  9. Embodiment of Legged Robots Emerged in Evolutionary Design: Pseudo Passive Dynamic Walkers

    OpenAIRE

    Matsushita, Kojiro; Yokoi, Hiroshi

    2008-01-01

    An objective of this paper is to illustrate a physical representation of the embodiment on legged locomotion. Embodiment is here defined as physical features that reduce control complexity and energy consumption of legged robots. In this method, the embodiment of

  10. Towards autonomous locomotion: CPG-based control of smooth 3D slithering gait transition of a snake-like robot.

    Science.gov (United States)

    Bing, Zhenshan; Cheng, Long; Chen, Guang; Röhrbein, Florian; Huang, Kai; Knoll, Alois

    2017-04-04

    Snake-like robots with 3D locomotion ability have significant advantages of adaptive travelling in diverse complex terrain over traditional legged or wheeled mobile robots. Despite numerous developed gaits, these snake-like robots suffer from unsmooth gait transitions by changing the locomotion speed, direction, and body shape, which would potentially cause undesired movement and abnormal torque. Hence, there exists a knowledge gap for snake-like robots to achieve autonomous locomotion. To address this problem, this paper presents the smooth slithering gait transition control based on a lightweight central pattern generator (CPG) model for snake-like robots. First, based on the convergence behavior of the gradient system, a lightweight CPG model with fast computing time was designed and compared with other widely adopted CPG models. Then, by reshaping the body into a more stable geometry, the slithering gait was modified, and studied based on the proposed CPG model, including the gait transition of locomotion speed, moving direction, and body shape. In contrast to sinusoid-based method, extensive simulations and prototype experiments finally demonstrated that smooth slithering gait transition can be effectively achieved using the proposed CPG-based control method without generating undesired locomotion and abnormal torque.

  11. Reinforcement learning of periodical gaits in locomotion robots

    Science.gov (United States)

    Svinin, Mikhail; Yamada, Kazuyaki; Ushio, S.; Ueda, Kanji

    1999-08-01

    Emergence of stable gaits in locomotion robots is studied in this paper. A classifier system, implementing an instance- based reinforcement learning scheme, is used for sensory- motor control of an eight-legged mobile robot. Important feature of the classifier system is its ability to work with the continuous sensor space. The robot does not have a prior knowledge of the environment, its own internal model, and the goal coordinates. It is only assumed that the robot can acquire stable gaits by learning how to reach a light source. During the learning process the control system, is self-organized by reinforcement signals. Reaching the light source defines a global reward. Forward motion gets a local reward, while stepping back and falling down get a local punishment. Feasibility of the proposed self-organized system is tested under simulation and experiment. The control actions are specified at the leg level. It is shown that, as learning progresses, the number of the action rules in the classifier systems is stabilized to a certain level, corresponding to the acquired gait patterns.

  12. Swing-leg trajectory of running guinea fowl suggests task-level priority of force regulation rather than disturbance rejection.

    Directory of Open Access Journals (Sweden)

    Yvonne Blum

    Full Text Available To achieve robust and stable legged locomotion in uneven terrain, animals must effectively coordinate limb swing and stance phases, which involve distinct yet coupled dynamics. Recent theoretical studies have highlighted the critical influence of swing-leg trajectory on stability, disturbance rejection, leg loading and economy of walking and running. Yet, simulations suggest that not all these factors can be simultaneously optimized. A potential trade-off arises between the optimal swing-leg trajectory for disturbance rejection (to maintain steady gait versus regulation of leg loading (for injury avoidance and economy. Here we investigate how running guinea fowl manage this potential trade-off by comparing experimental data to predictions of hypothesis-based simulations of running over a terrain drop perturbation. We use a simple model to predict swing-leg trajectory and running dynamics. In simulations, we generate optimized swing-leg trajectories based upon specific hypotheses for task-level control priorities. We optimized swing trajectories to achieve i constant peak force, ii constant axial impulse, or iii perfect disturbance rejection (steady gait in the stance following a terrain drop. We compare simulation predictions to experimental data on guinea fowl running over a visible step down. Swing and stance dynamics of running guinea fowl closely match simulations optimized to regulate leg loading (priorities i and ii, and do not match the simulations optimized for disturbance rejection (priority iii. The simulations reinforce previous findings that swing-leg trajectory targeting disturbance rejection demands large increases in stance leg force following a terrain drop. Guinea fowl negotiate a downward step using unsteady dynamics with forward acceleration, and recover to steady gait in subsequent steps. Our results suggest that guinea fowl use swing-leg trajectory consistent with priority for load regulation, and not for steadiness of gait

  13. Swing-Leg Trajectory of Running Guinea Fowl Suggests Task-Level Priority of Force Regulation Rather than Disturbance Rejection

    Science.gov (United States)

    Blum, Yvonne; Vejdani, Hamid R.; Birn-Jeffery, Aleksandra V.; Hubicki, Christian M.; Hurst, Jonathan W.; Daley, Monica A.

    2014-01-01

    To achieve robust and stable legged locomotion in uneven terrain, animals must effectively coordinate limb swing and stance phases, which involve distinct yet coupled dynamics. Recent theoretical studies have highlighted the critical influence of swing-leg trajectory on stability, disturbance rejection, leg loading and economy of walking and running. Yet, simulations suggest that not all these factors can be simultaneously optimized. A potential trade-off arises between the optimal swing-leg trajectory for disturbance rejection (to maintain steady gait) versus regulation of leg loading (for injury avoidance and economy). Here we investigate how running guinea fowl manage this potential trade-off by comparing experimental data to predictions of hypothesis-based simulations of running over a terrain drop perturbation. We use a simple model to predict swing-leg trajectory and running dynamics. In simulations, we generate optimized swing-leg trajectories based upon specific hypotheses for task-level control priorities. We optimized swing trajectories to achieve i) constant peak force, ii) constant axial impulse, or iii) perfect disturbance rejection (steady gait) in the stance following a terrain drop. We compare simulation predictions to experimental data on guinea fowl running over a visible step down. Swing and stance dynamics of running guinea fowl closely match simulations optimized to regulate leg loading (priorities i and ii), and do not match the simulations optimized for disturbance rejection (priority iii). The simulations reinforce previous findings that swing-leg trajectory targeting disturbance rejection demands large increases in stance leg force following a terrain drop. Guinea fowl negotiate a downward step using unsteady dynamics with forward acceleration, and recover to steady gait in subsequent steps. Our results suggest that guinea fowl use swing-leg trajectory consistent with priority for load regulation, and not for steadiness of gait. Swing-leg

  14. Genetic association between leg conformation in young pigs and sow reproduction

    DEFF Research Database (Denmark)

    Le, Thu Hong; Nilsson, Katja; Norberg, Elise

    2015-01-01

    Lameness is an issue of concern in pig production due both to animal welfare and to economical aspects. Lame sows are believed to suffer from pain and stress which is reported to have a negative influence on reproduction. Leg conformation and locomotion traits in young animals are associated...... of simultaneous improvement of both leg quality and reproduction performance by selecting on sound leg conformation and locomotion of young pigs....

  15. On the biomimetic design of agile-robot legs.

    Science.gov (United States)

    Garcia, Elena; Arevalo, Juan Carlos; Muñoz, Gustavo; Gonzalez-de-Santos, Pablo

    2011-01-01

    The development of functional legged robots has encountered its limits in human-made actuation technology. This paper describes research on the biomimetic design of legs for agile quadrupeds. A biomimetic leg concept that extracts key principles from horse legs which are responsible for the agile and powerful locomotion of these animals is presented. The proposed biomimetic leg model defines the effective leg length, leg kinematics, limb mass distribution, actuator power, and elastic energy recovery as determinants of agile locomotion, and values for these five key elements are given. The transfer of the extracted principles to technological instantiations is analyzed in detail, considering the availability of current materials, structures and actuators. A real leg prototype has been developed following the biomimetic leg concept proposed. The actuation system is based on the hybrid use of series elasticity and magneto-rheological dampers which provides variable compliance for natural motion. From the experimental evaluation of this prototype, conclusions on the current technological barriers to achieve real functional legged robots to walk dynamically in agile locomotion are presented.

  16. On the Biomimetic Design of Agile-Robot Legs

    Directory of Open Access Journals (Sweden)

    Pablo Gonzalez-de-Santos

    2011-11-01

    Full Text Available The development of functional legged robots has encountered its limits in human-made actuation technology. This paper describes research on the biomimetic design of legs for agile quadrupeds. A biomimetic leg concept that extracts key principles from horse legs which are responsible for the agile and powerful locomotion of these animals is presented. The proposed biomimetic leg model defines the effective leg length, leg kinematics, limb mass distribution, actuator power, and elastic energy recovery as determinants of agile locomotion, and values for these five key elements are given. The transfer of the extracted principles to technological instantiations is analyzed in detail, considering the availability of current materials, structures and actuators. A real leg prototype has been developed following the biomimetic leg concept proposed. The actuation system is based on the hybrid use of series elasticity and magneto-rheological dampers which provides variable compliance for natural motion. From the experimental evaluation of this prototype, conclusions on the current technological barriers to achieve real functional legged robots to walk dynamically in agile locomotion are presented.

  17. On the Biomimetic Design of Agile-Robot Legs

    Science.gov (United States)

    Garcia, Elena; Arevalo, Juan Carlos; Muñoz, Gustavo; Gonzalez-de-Santos, Pablo

    2011-01-01

    The development of functional legged robots has encountered its limits in human-made actuation technology. This paper describes research on the biomimetic design of legs for agile quadrupeds. A biomimetic leg concept that extracts key principles from horse legs which are responsible for the agile and powerful locomotion of these animals is presented. The proposed biomimetic leg model defines the effective leg length, leg kinematics, limb mass distribution, actuator power, and elastic energy recovery as determinants of agile locomotion, and values for these five key elements are given. The transfer of the extracted principles to technological instantiations is analyzed in detail, considering the availability of current materials, structures and actuators. A real leg prototype has been developed following the biomimetic leg concept proposed. The actuation system is based on the hybrid use of series elasticity and magneto-rheological dampers which provides variable compliance for natural motion. From the experimental evaluation of this prototype, conclusions on the current technological barriers to achieve real functional legged robots to walk dynamically in agile locomotion are presented. PMID:22247667

  18. Design and analysis of an optimal hopper for use in resonance-based locomotion

    NARCIS (Netherlands)

    Wanders, Ivor; Folkertsma, Gerrit Adriaan; Stramigioli, Stefano

    Quadrupedal running is an efficient form of locomotion found in nature, which serves as an inspiration for robotics. We believe that a resonance-based approach is the path towards energy-efficient legged locomotion and running robots. The first step in working towards this goal is creating an

  19. LocoKit - A Construction Kit for Exploration of Morphology of Legged Robots

    DEFF Research Database (Denmark)

    Larsen, Jørgen Christian; Støy, Kasper

    2011-01-01

    . This is however not always easy, since robots are often built as a fixed system with a limited possibility of changing the morphology without redesign a significant part of the robot. This work is focusing on the creation of a robotic construction kit specifically aimed at easing the process of constructing......Producing steady stable and energy efficient locomotion in legged robots with the ability to walk in unknown terrain is a big challenge in robotics. In addressing this challenge, it is often desirable to experiment with different morphologies and see how they influence on the way the robot walks...... legged robots. This is accomplished by giving the creator the possibility to easily do morphological changes to the robot even after it have been build, to see how it effects the robot’s ability to walk in unknown terrain....

  20. Leg Swelling

    Science.gov (United States)

    ... ed. New York, N.Y.: The McGraw Hill Companies; 2016. http://www.accessmedicine.com. Accessed Dec. 31, ... http://www.mayoclinic.org/symptoms/leg-swelling/basics/definition/SYM-20050910 . Mayo Clinic Footer Legal Conditions and ...

  1. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion II

    Science.gov (United States)

    Lee, Scott

    2015-01-01

    In the second paper of this series, the effect of transverse femoral stresses due to locomotion in theropod dinosaurs of different sizes was examined for the case of an unchanging leg geometry. Students are invariably thrilled to learn about theropod dinosaurs, and this activity applies the concepts of torque and stress to the issue of theropod…

  2. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion

    Science.gov (United States)

    Lee, Scott

    2015-01-01

    In our first article on scaling in theropod dinosaurs, the longitudinal stress in the leg bones due to supporting the weight of the animal was studied and found not to control the dimensions of the femur. As a continuation of our study of elasticity in dinosaur bones, we now examine the transverse stress in the femur due to locomotion and find…

  3. Robot locomotion on weak ground

    Science.gov (United States)

    Qian, Feifei; Li, Chen; Umbanhowar, Paul; Goldman, Daniel

    2012-11-01

    Natural substrates like sand, soil, and leaf litter vary widely in penetration resistance. Little is known about how animals (and increasingly robots) respond to this variation. To address this deficit, we built an air fluidized bed trackway, in which we control penetration resistance of 1mm granular substrates down to zero by increasing the upward flow rate, Q , to the fluidization transition. Using a 2 . 5 kg bio-inspired hexapedal robot as our model locomotor, we systematically study how locomotion performance (average forward speed, v) varies with penetration resistance, limb kinematics, and foot morphology. Average robot speed decreases with increasing Q, and decreases faster for robots with higher leg frequency or narrower leg width. A previously developed model, which captured the robot's performance on granular media with Q = 0 , also captures the observed performance for weakened states with Q > 0 . A single dimensionless control parameter from the model, which combines gait and ground parameters, determines v for all penetration resistances. Our ground control technique and modeling approach provide a way to probe and understand the limits of locomotor performance on yielding substrates.

  4. Recording and analysis of locomotion in dairy cows with 3D accelerometers

    NARCIS (Netherlands)

    Mol, de R.M.; Lammers, R.J.H.; Pompe, J.C.A.M.; Ipema, A.H.; Hogewerf, P.H.

    2009-01-01

    An automated method for lameness detection can be an alternative for detection by regular observations. Accelerometers attached to a leg of the dairy cow can be used to record the locomotion of a dairy cow. In an experiment the 3D acceleration of the right hind leg during walking of three dairy cows

  5. Intersegmental coordination of cockroach locomotion: adaptive control of centrally coupled pattern generator circuits

    Directory of Open Access Journals (Sweden)

    Einat eFuchs

    2011-01-01

    Full Text Available Animals’ ability to demonstrate both stereotyped and adaptive locomotor behavior is largely dependent on the interplay between centrally-generated motor patterns and the sensory inputs that shape them. We utilized a combined experimental and theoretical approach to investigate the relative importance of CPG interconnections vs. intersegmental afferents in the cockroach: an animal that is renowned for rapid and stable locomotion. We simultaneously recorded coxal levator and depressor motor neurons (MN in the thoracic ganglia of Periplaneta americana, while sensory feedback was completely blocked or allowed only from one intact stepping leg. In the absence of sensory feedback, we observed a coordination pattern with consistent phase relationship that shares similarities with a double tripod gait, suggesting central, feedforward control. This intersegmental coordination pattern was then reinforced in the presence of sensory feedback from a single stepping leg. Specifically, we report on transient stabilization of phase differences between activity recorded in the middle and hind thoracic MN following individual front-leg steps, suggesting a role for afferent phasic information in the coordination of motor circuits at the different hemiganglia. Data were further analyzed using stochastic models of coupled oscillators and maximum likelihood techniques to estimate underlying physiological parameters, such as uncoupled endogenous frequencies of hemisegmental oscillators and coupling strengths and directions. We found that descending ipsilateral coupling is stronger than ascending coupling, while left-right coupling in both the meso- and meta-thoracic ganglia appear to be symmetrical. We discuss our results in comparison with recent findings in stick insects that share similar neural and body architectures, and argue that the two species may exemplify opposite extremes of a fast-slow locomotion continuum, mediated through different intersegmental

  6. [The concept and definition of locomotive syndrome in a super-aged society].

    Science.gov (United States)

    Nakamura, Kozo; Yoshimura, Noriko; Akune, Toru; Ogata, Toru; Tanaka, Sakae

    2014-10-01

    The population of elderly individuals who need nursing care is rapidly increasing in Japan. Locomotive syndrome involves a decrease in mobility due to locomotive organ dysfunction, and increases risk for dependency on nursing care service. Because gait speed and chair stand time are correlated with such risks, patients with locomotive syndrome are assessed using brief methods such as the two-step test, which involves dividing the maximum stride length by the height of the patient, and the stand-up test, which involves standing on one or both legs at different heights. One leg standing and squatting are recommended as beneficial locomotive home exercises. Locomotive syndrome has been recognized widely in Japan, and included in the National Health Promotion Movement (2013-2022).

  7. Broken Leg

    Science.gov (United States)

    ... the leg, which can result in a fracture. Stress fractures outside of sport situations are more common in people who have: ... shoes. Choose the appropriate shoe for your favorite sports or activities. And ... can prevent stress fractures. Rotate running with swimming or biking. If ...

  8. Peristaltic Wave Locomotion and Shape Morphing with a Millipede Inspired System

    Science.gov (United States)

    Spinello, Davide; Fattahi, Javad S.

    2017-08-01

    We present the mechanical model of a bio-inspired deformable system, modeled as a Timoshenko beam, which is coupled to a substrate by a system of distributed elements. The locomotion action is inspired by the coordinated motion of coupling elements that mimic the legs of millipedes and centipedes, whose leg-to-ground contact can be described as a peristaltic displacement wave. The multi-legged structure is crucial in providing redundancy and robustness in the interaction with unstructured environments and terrains. A Lagrangian approach is used to derive the governing equations of the system that couple locomotion and shape morphing. Features and limitations of the model are illustrated with numerical simulations.

  9. Lack of adaptation during prolonged split-belt locomotion in the intact and spinal cat.

    Science.gov (United States)

    Kuczynski, Victoria; Telonio, Alessandro; Thibaudier, Yann; Hurteau, Marie-France; Dambreville, Charline; Desrochers, Etienne; Doelman, Adam; Ross, Declan; Frigon, Alain

    2017-09-01

    During split-belt locomotion in humans where one leg steps faster than the other, the symmetry of step lengths and double support periods of the slow and fast legs is gradually restored. When returning to tied-belt locomotion, there is an after-effect, with a reversal in the asymmetry observed in the early split-belt period, indicating that the new pattern was stored within the central nervous system. In this study, we investigated if intact and spinal-transected cats show a similar pattern of adaptation to split-belt locomotion by measuring kinematic variables and electromyography before, during and after 10 min of split-belt locomotion. The results show that cats do not adapt to prolonged split-belt locomotion. Our results suggest an important physiological difference in how cats and humans respond to prolonged asymmetric locomotion. In humans, gait adapts to prolonged walking on a split-belt treadmill, where one leg steps faster than the other, by gradually restoring the symmetry of interlimb kinematic variables, such as double support periods and step lengths, and by reducing muscle activity (EMG, electromyography). The adaptation is also characterized by reversing the asymmetry of interlimb variables observed during the early split-belt period when returning to tied-belt locomotion, termed an after-effect. To determine if cats adapt to prolonged split-belt locomotion and to assess if spinal locomotor circuits participate in the adaptation, we measured interlimb variables and EMG in intact and spinal-transected cats before, during and after 10 min of split-belt locomotion. In spinal cats, only the hindlimbs performed stepping with the forelimbs stationary. In intact and spinal cats, step lengths and double support periods were, on average, symmetric, during tied-belt locomotion. They became asymmetric during split-belt locomotion and remained asymmetric throughout the split-belt period. Upon returning to tied-belt locomotion, symmetry was immediately restored

  10. A simple running model with rolling contact and its role as a template for dynamic locomotion on a hexapod robot.

    Science.gov (United States)

    Huang, Ke-Jung; Huang, Chun-Kai; Lin, Pei-Chun

    2014-10-07

    We report on the development of a robot's dynamic locomotion based on a template which fits the robot's natural dynamics. The developed template is a low degree-of-freedom planar model for running with rolling contact, which we call rolling spring loaded inverted pendulum (R-SLIP). Originating from a reduced-order model of the RHex-style robot with compliant circular legs, the R-SLIP model also acts as the template for general dynamic running. The model has a torsional spring and a large circular arc as the distributed foot, so during locomotion it rolls on the ground with varied equivalent linear stiffness. This differs from the well-known spring loaded inverted pendulum (SLIP) model with fixed stiffness and ground contact points. Through dimensionless steps-to-fall and return map analysis, within a wide range of parameter spaces, the R-SLIP model is revealed to have self-stable gaits and a larger stability region than that of the SLIP model. The R-SLIP model is then embedded as the reduced-order 'template' in a more complex 'anchor', the RHex-style robot, via various mapping definitions between the template and the anchor. Experimental validation confirms that by merely deploying the stable running gaits of the R-SLIP model on the empirical robot with simple open-loop control strategy, the robot can easily initiate its dynamic running behaviors with a flight phase and can move with similar body state profiles to those of the model, in all five testing speeds. The robot, embedded with the SLIP model but performing walking locomotion, further confirms the importance of finding an adequate template of the robot for dynamic locomotion.

  11. A simple running model with rolling contact and its role as a template for dynamic locomotion on a hexapod robot

    International Nuclear Information System (INIS)

    Huang, Ke-Jung; Huang, Chun-Kai; Lin, Pei-Chun

    2014-01-01

    We report on the development of a robot’s dynamic locomotion based on a template which fits the robot’s natural dynamics. The developed template is a low degree-of-freedom planar model for running with rolling contact, which we call rolling spring loaded inverted pendulum (R-SLIP). Originating from a reduced-order model of the RHex-style robot with compliant circular legs, the R-SLIP model also acts as the template for general dynamic running. The model has a torsional spring and a large circular arc as the distributed foot, so during locomotion it rolls on the ground with varied equivalent linear stiffness. This differs from the well-known spring loaded inverted pendulum (SLIP) model with fixed stiffness and ground contact points. Through dimensionless steps-to-fall and return map analysis, within a wide range of parameter spaces, the R-SLIP model is revealed to have self-stable gaits and a larger stability region than that of the SLIP model. The R-SLIP model is then embedded as the reduced-order ‘template’ in a more complex ‘anchor’, the RHex-style robot, via various mapping definitions between the template and the anchor. Experimental validation confirms that by merely deploying the stable running gaits of the R-SLIP model on the empirical robot with simple open-loop control strategy, the robot can easily initiate its dynamic running behaviors with a flight phase and can move with similar body state profiles to those of the model, in all five testing speeds. The robot, embedded with the SLIP model but performing walking locomotion, further confirms the importance of finding an adequate template of the robot for dynamic locomotion. (paper)

  12. Locomotive Syndrome: Definition and Management

    OpenAIRE

    Nakamura, Kozo; Ogata, Toru

    2016-01-01

    Locomotive syndrome is a condition of reduced mobility due to impairment of locomotive organs. Since upright bipedal walking involves minutely controlled movement patterns, impairment of any aspect of the locomotive organs has the potential to adversely affect it. In addition to trauma, chronic diseases of the locomotive organs, which progress with repeated bouts of acute exacerbations, are common causes of the locomotive syndrome. In Japan?s super-aging society, many people are likely to exp...

  13. Models of Snail Locomotion

    Science.gov (United States)

    Chan, Brian; Hosoi, Anette

    2003-11-01

    All snails move over a thin layer of mucus using periodic deformations of their muscular foot. This unusual mode of locomotion can be modeled as a thin film of viscous fluid sandwiched between a flexible membrane and a rigid substrate. We present theoretical, numerical and experimental studies of locomotion via viscous stresses generated in thin films. Study of snail locomotion led us to design and construct several mechanical models: RoboSnail 1 which mimics snail locomotion incorrectly, but still proves to be a valid propulsion device over a thin viscous fluid layer and RoboSnail 2 which mimics land snails and uses forward-propagating compression waves on the base of the foot. Experimental results from the prototype machines are compared with long wavelength numerical and theoretical models.

  14. Night Leg Cramps

    Science.gov (United States)

    Symptoms Night leg cramps By Mayo Clinic Staff Night leg cramps, also called nocturnal leg cramps, are painful, involuntary contractions or spasms of muscles in your legs, usually occurring when you're in bed. Night ...

  15. Obstacle Avoidance in Groping Locomotion of a Humanoid Robot

    Directory of Open Access Journals (Sweden)

    Masahiro Ohka

    2008-11-01

    Full Text Available This paper describes the development of an autonomous obstacle-avoidance method that operates in conjunction with groping locomotion on the humanoid robot Bonten-Maru II. Present studies on groping locomotion consist of basic research in which humanoid robot recognizes its surroundings by touching and groping with its arm on the flat surface of a wall. The robot responds to the surroundings by performing corrections to its orientation and locomotion direction. During groping locomotion, however, the existence of obstacles within the correction area creates the possibility of collisions. The objective of this paper is to develop an autonomous method to avoid obstacles in the correction area by applying suitable algorithms to the humanoid robot's control system. In order to recognize its surroundings, six-axis force sensors were attached to both robotic arms as end effectors for force control. The proposed algorithm refers to the rotation angle of the humanoid robot's leg joints due to trajectory generation. The algorithm relates to the groping locomotion via the measured groping angle and motions of arms. Using Bonten-Maru II, groping experiments were conducted on a wall's surface to obtain wall orientation data. By employing these data, the humanoid robot performed the proposed method autonomously to avoid an obstacle present in the correction area. Results indicate that the humanoid robot can recognize the existence of an obstacle and avoid it by generating suitable trajectories in its legs.

  16. Unified Phase Variables of Relative Degree Two for Human Locomotion.

    Science.gov (United States)

    Villarreal, Dario J; Gregg, Robert D

    2016-08-01

    A starting point to achieve stable locomotion is synchronizing the leg joint kinematics during the gait cycle. Some biped robots parameterize a nonlinear controller (e.g., input-output feedback linearization) whose main objective is to track specific kinematic trajectories as a function of a single mechanical variable (i.e., a phase variable) in order to allow the robot to walk. A phase variable capable of parameterizing the entire gait cycle, the hip phase angle, has been used to control wearable robots and was recently shown to provide a robust representation of the phase of human gait. However, this unified phase variable relies on hip velocity, which is difficult to measure in real-time and prevents the use of derivative corrections in phase-based controllers for wearable robots. One derivative of this phase variable yields accelerations (i.e., the equations of motion), so the system is said to be relative degree-one. This means that there are states of the system that cannot be controlled. The goal of this paper is to offer relative degree-two alternatives to the hip phase angle and examine their robustness for parameterizing human gait.

  17. Bio-Inspired Design and Kinematic Analysis of Dung Beetle-Like Legs

    DEFF Research Database (Denmark)

    Aditya, Sai Krishna Venkata; Ignasov, Jevgeni; Filonenko, Konstantin

    The African dung beetle Scarabaeus galenus can use its front legs to walk and manipulate or form a dung ball. The interesting multifunctional legs have not been fully investigated or even used as inspiration for robot leg design. Thus, in this paper, we present the development of real dung beetle......-like front legs based on biological investigation. As a result, each leg consists of three main segments which were built using 3D printing. The segments were combined with in total four active DOFs in order to mimic locomotion and object manipulation of the beetle. Kinematics analysis of the leg was also...

  18. Hybrid Locomotion Evaluation for a Novel Amphibious Spherical Robot

    Directory of Open Access Journals (Sweden)

    Huiming Xing

    2018-01-01

    Full Text Available We describe the novel, multiply gaited, vectored water-jet, hybrid locomotion-capable, amphibious spherical robot III (termed ASR-III featuring a wheel-legged, water-jet composite driving system incorporating a lifting and supporting wheel mechanism (LSWM and mechanical legs with a water-jet thruster. The LSWM allows the ASR-III to support the body and slide flexibly on smooth (flat terrain. The composite driving system facilitates two on-land locomotion modes (sliding and walking and underwater locomotion mode with vectored thrusters, improving adaptability to the amphibious environment. Sliding locomotion improves the stability and maneuverability of ASR-III on smooth flat terrain, whereas walking locomotion allows ASR-III to conquer rough terrain. We used both forward and reverse kinematic models to evaluate the walking and sliding gait efficiency. The robot can also realize underwater locomotion with four vectored water-jet thrusters, and is capable of forward motion, heading angle control and depth control. We evaluated LSWM efficiency and the sliding velocities associated with varying extensions of the LSWM. To explore gait stability and mobility, we performed on-land experiments on smooth flat terrain to define the optimal stride length and frequency. We also evaluated the efficacy of waypoint tracking when the sliding gait was employed, using a closed-loop proportional-integral-derivative (PID control mechanism. Moreover, experiments of forward locomotion, heading angle control and depth control were conducted to verify the underwater performance of ASR-III. Comparison of the previous robot and ASR-III demonstrated the ASR-III had better amphibious motion performance.

  19. Exotendons for assistance of human locomotion

    Directory of Open Access Journals (Sweden)

    van den Bogert Antonie J

    2003-10-01

    Full Text Available Abstract Background Powered robotic exoskeletons for assistance of human locomotion are currently under development for military and medical applications. The energy requirements for such devices are excessive, and this has become a major obstacle for practical applications. Legged locomotion in many animals, however, is very energy efficient. We propose that poly-articular elastic mechanisms are a major contributor to the economy of locomotion in such specialized animals. Consequently, it should be possible to design unpowered assistive devices that make effective use of similar mechanisms. Methods A passive assistive technology is presented, based on long elastic cords attached to an exoskeleton and guided by pulleys placed at the joints. A general optimization procedure is described for finding the best geometrical arrangement of such "exotendons" for assisting a specific movement. Optimality is defined either as minimal residual joint moment or as minimal residual joint power. Four specific exotendon systems with increasing complexity are considered. Representative human gait data were used to optimize each of these four systems to achieve maximal assistance for normal walking. Results The most complex exotendon system, with twelve pulleys per limb, was able to reduce the joint moments required for normal walking by 71% and joint power by 74%. A simpler system, with only three pulleys per limb, could reduce joint moments by 46% and joint power by 47%. Conclusion It is concluded that unpowered passive elastic devices can substantially reduce the muscle forces and the metabolic energy needed for walking, without requiring a change in movement. When optimally designed, such devices may allow independent locomotion in patients with large deficits in muscle function.

  20. A Dung Beetle-like Leg and its Adaptive Neural Control

    DEFF Research Database (Denmark)

    Di Canio, Giuliano; Stoyanov, Stoyan; Larsen, Jørgen Christian

    2016-01-01

    Dung beetles show fascinating locomotion abilities. They can use their legs to not only walk but also manipulate objects. Furthermore, they can perform their leg movements at a proper frequency with respect to their biomechanical properties and quickly adapt the movements to deal with external pe...

  1. Balanced gait generations of a two-legged robot on sloping surface

    Indian Academy of Sciences (India)

    legged robot moving up and down through the sloping surface is presented. The gait of the lower links during locomotion is obtained after assuming suitable trajectories for the swing leg and hip joint. The trunk motion is initially generated based on ...

  2. ADAPTATIONAL AND LEARNING-PROCESSES DURING HUMAN SPLIT-BELT LOCOMOTION - INTERACTION BETWEEN CENTRAL MECHANISMS AND AFFERENT INPUT

    NARCIS (Netherlands)

    PROKOP, T; BERGER, W; ZIJLSTRA, W; DIETZ, [No Value

    1995-01-01

    Split-belt locomotion (i.e., walking with unequal leg speeds) requires a rapid adaptation of biomechanical parameters and therefore of leg muscle electromyographic (EMG) activity. This adaptational process during the first strides of asymmetric gait as well as learning effects induced by repetition

  3. Locomotion Efficiency Optimization of Biologically Inspired Snake Robots

    OpenAIRE

    Eleni Kelasidi; Mansoureh Jesmani; Kristin Y. Pettersen; Jan Tommy Gravdahl

    2018-01-01

    Snake robots constitute bio-inspired solutions that have been studied due to their ability to move in challenging environments where other types of robots, such as wheeled or legged robots, usually fail. In this paper, we consider both land-based and swimming snake robots. One of the principal concerns of the bio-inspired snake robots is to increase the motion efficiency in terms of the forward speed by improving the locomotion methods. Furthermore, energy efficiency becomes a crucial challen...

  4. Implementing gait pattern control and transition for legged locomotion

    International Nuclear Information System (INIS)

    Yang, Zhijun; Karamanoglu, Mehmet; Rocha, Marlon V; França, Felipe M G; Lima, Priscila M V

    2014-01-01

    In this work, a generalised central pattern generator (CPG) model is formulated to generate a full range of gait patterns for a hexapod insect. To this end, a recurrent neuronal network module, as the building block for rhythmic patterns, is proposed to extend the concept of oscillatory building blocks (OBB) for constructing a CPG model. The model is able to make transitions between different gait patterns by simply adjusting one model parameter. Simulation results are further presented to show the effectiveness and performance of the CPG network

  5. Leg Injuries and Disorders

    Science.gov (United States)

    Your legs are made up of bones, blood vessels, muscles, and other connective tissue. They are important for motion ... falling, or having an accident can damage your legs. Common leg injuries include sprains and strains, joint ...

  6. Central Pattern Generator for Locomotion: Anatomical, Physiological and Pathophysiological Considerations

    Directory of Open Access Journals (Sweden)

    Pierre A. Guertin

    2013-02-01

    Full Text Available This article provides a perspective on major innovations over the past century in research on the spinal cord and, specifically, on specialized spinal circuits involved in the control of rhythmic locomotor pattern generation and modulation. Pioneers such as Charles Sherrington and Thomas Graham Brown have conducted experiments in the early twentieth century that changed our views of the neural control of locomotion. Their seminal work supported subsequently by several decades of evidence has led to the conclusion that walking, flying and swimming are largely controlled by a network of spinal neurons generally referred to as the central pattern generator (CPG for locomotion. It has been subsequently demonstrated across all vertebrate species examined, from lampreys to humans, that this CPG is capable, under some conditions, to self-produce, even in absence of descending or peripheral inputs, basic rhythmic and coordinated locomotor movements. Recent evidence suggests, in turn, that plasticity changes of some CPG elements may contribute to the development of specific pathophysiological conditions associated with impaired locomotion or spontaneous locomotor-like movements. This article constitutes a comprehensive review summarizing key findings on the CPG as well as on its potential role in Restless Leg Syndrome (RLS, Periodic Leg Movement (PLM, and Alternating Leg Muscle Activation (ALMA. Special attention will be paid to the role of the CPG in a recently identified, and uniquely different neurological disorder, called the Uner Tan Syndrome.

  7. Joint variable stiffness of musculoskeletal leg mechanism for quadruped robot

    OpenAIRE

    Lei, J; Zhu, J; Xie, P; Tokhi, MO

    2017-01-01

    © The Author(s) 2017. When the quadruped robot is in locomotion such as jumping and running with higher speed, there is non-continuous contact force between the foot and the environment inevitably. In order to achieve the flexible force interaction of the bionic legs with the environment, it is necessary to analyze the joint angular stiffness of the bionic leg. In this article, based on the designing principles of the bionics, light-weighted, and flexible, a kind of musculoskeletal bionic leg...

  8. Locomotive Syndrome: Definition and Management.

    Science.gov (United States)

    Nakamura, Kozo; Ogata, Toru

    Locomotive syndrome is a condition of reduced mobility due to impairment of locomotive organs. Since upright bipedal walking involves minutely controlled movement patterns, impairment of any aspect of the locomotive organs has the potential to adversely affect it. In addition to trauma, chronic diseases of the locomotive organs, which progress with repeated bouts of acute exacerbations, are common causes of the locomotive syndrome. In Japan's super-aging society, many people are likely to experience locomotive syndrome in the later part of their lives. Exercise intervention is effective in improving motor function, but because the subjects are elderly people with significant degenerative diseases of the locomotor organs, caution should be taken in choosing the type and intensity of exercise. The present review discusses the definition, current burden, diagnosis and interventions pertaining to the locomotive syndrome. The concept and measures are spreading throughout Japan as one of the national health policy targets.

  9. Vibroacoustic characteristics of mine locomotives

    Energy Technology Data Exchange (ETDEWEB)

    Chigirinskii, S.E.; Ponomarev, N.S.; Leiman, Ya.A.

    1982-11-01

    The paper discusses noise pollution caused by locomotives used for mine haulage in underground mining. Noise pollution in a mine working and at the driver working place is measured. Mechanical vibrations of the floor in the driver cab are also determined. Noise pollution and mechanical vibrations of 3 locomotive types are comparatively evaluated: the AM-8D electric locomotive, the GR-4 inertia-type locomotive and the 1D-8 diesel locomotive. The results of investigations are shown in 2 tables. The inertia-type locomotive causes the most intensive noise pollution. Noise pollution of the diesel locomotive has been successfully suppressed by a system of shock absorbers. The following methods for noise and vibration control are discussed: use of soundproof cabs, damping vibrations at the driver's seat, use of motors with noise abatement systems and shock absorbers. (In Russian)

  10. Peripheral artery disease - legs

    Science.gov (United States)

    Peripheral vascular disease; PVD; PAD; Arteriosclerosis obliterans; Blockage of leg arteries; Claudication; Intermittent claudication; Vaso-occlusive disease of the legs; Arterial insufficiency of ...

  11. A sensory-driven controller for quadruped locomotion.

    Science.gov (United States)

    Ferreira, César; Santos, Cristina P

    2017-02-01

    Locomotion of quadruped robots has not yet achieved the harmony, flexibility, efficiency and robustness of its biological counterparts. Biological research showed that spinal reflexes are crucial for a successful locomotion in the most varied terrains. In this context, the development of bio-inspired controllers seems to be a good way to move toward an efficient and robust robotic locomotion, by mimicking their biological counterparts. This contribution presents a sensory-driven controller designed for the simulated Oncilla quadruped robot. In the proposed reflex controller, movement is generated through the robot's interactions with the environment, and therefore, the controller is solely dependent on sensory information. The results show that the reflex controller is capable of producing stable quadruped locomotion with a regular stepping pattern. Furthermore, it is capable of dealing with slopes without changing the parameters and with small obstacles, overcoming them successfully. Finally, system robustness was verified by adding noise to sensors and actuators and also delays.

  12. Task driven optimal leg trajectories in insect-scale legged microrobots

    Science.gov (United States)

    Doshi, Neel; Goldberg, Benjamin; Jayaram, Kaushik; Wood, Robert

    Origami inspired layered manufacturing techniques and 3D-printing have enabled the development of highly articulated legged robots at the insect-scale, including the 1.43g Harvard Ambulatory MicroRobot (HAMR). Research on these platforms has expanded its focus from manufacturing aspects to include design optimization and control for application-driven tasks. Consequently, the choice of gait selection, body morphology, leg trajectory, foot design, etc. have become areas of active research. HAMR has two controlled degrees-of-freedom per leg, making it an ideal candidate for exploring leg trajectory. We will discuss our work towards optimizing HAMR's leg trajectories for two different tasks: climbing using electroadhesives and level ground running (5-10 BL/s). These tasks demonstrate the ability of single platform to adapt to vastly different locomotive scenarios: quasi-static climbing with controlled ground contact, and dynamic running with un-controlled ground contact. We will utilize trajectory optimization methods informed by existing models and experimental studies to determine leg trajectories for each task. We also plan to discuss how task specifications and choice of objective function have contributed to the shape of these optimal leg trajectories.

  13. Morphological self stabilization of locomotion gaits: illustration on a few examples from bio-inspired locomotion.

    Science.gov (United States)

    Chevallereau, Christine; Boyer, Frédéric; Porez, Mathieu; Mauny, Johan; Aoustin, Yannick

    2017-06-20

    To a large extent, robotics locomotion can be viewed as cyclic motions, named gaits. Due to the high complexity of the locomotion dynamics, to find the control laws that ensure an expected gait and its stability with respect to external perturbations, is a challenging issue for feedback control. To address this issue, a promising way is to take inspiration from animals that intensively exploit the interactions of the passive degrees of freedom of their body with their physical surroundings, to outsource the high-level exteroceptive feedback control to low-level proprioceptive ones. In this case, passive interactions can ensure most of the expected control goals. In this article, we propose a methodological framework to study the role of morphology in the design of locomotion gaits and their stability. This framework ranges from modelling to control aspects, and is illustrated through three examples from bio-inspired locomotion: a three-dimensional micro air vehicle in hovering flight, a pendular planar climber and a bipedal planar walker. In these three cases, we will see how simple considerations based on the morphology of the body can ensure the existence of passive stable gaits without requiring any high-level control.

  14. Partial model based walking control of quadruped locomotion robot with self renovation control function

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Hiroaki [Kisarazu National College of Technology, Kisarazu, Chiba (Japan); Nonami, Kenzo; Yanai, Takaaki [Chiba Univ. (Japan). Faculty of Engineering; Iguchi, Yoshihiko; Huang Qing Jiu [Chiba Univ. (Japan)

    2000-06-01

    It is considered that locomotion robots are aggressive under the circumstances where human hardly work, for example, in the nuclear power plant, in the bottom of the sea and on a planet. The injury and the fault of the robot might occur frequently under those circumstances. It is very important problem that the robot can realize the walking with the fault. This is very difficult problem for biped and quadruped robot to realize a stable walking in the case that actuator or sensor is broken. And, in walking of mammal, gait pattern is generated by neural oscillator existing in the spinal cord. In the case that a lower neural system is injured, mammal realize a walking by a higher neural system. Thus, mammal has a self renovation function. In this study, in order to realize the stable walking of the quadruped robot with fault, we discuss the control method with self renovation function for the fault of the decentralized controller and the angular sensor. First, we design the centralized controller of one leg by sliding mode control for the fault of decentralized controller. Second, Sky Hook Suspension Control is applied for the fault of the angular sensor. The proposed methods are verified by 3D simulations by CAD and experiments. (author)

  15. Feedback control of the neuromusculoskeletal system in a forward dynamics simulation of stair locomotion.

    Science.gov (United States)

    Selk Ghafari, A; Meghdari, A; Vossoughi, G

    2009-08-01

    The aim of this study is to employ feedback control loops to provide a stable forward dynamics simulation of human movement under repeated position constraint conditions in the environment, particularly during stair climbing. A ten-degrees-of-freedom skeletal model containing 18 Hill-type musculotendon actuators per leg was employed to simulate the model in the sagittal plane. The postural tracking and obstacle avoidance were provided by the proportional-integral-derivative controller according to the modulation of the time rate change of the joint kinematics. The stability of the model was maintained by controlling the velocity of the body's centre of mass according to the desired centre of pressure during locomotion. The parameters of the proposed controller were determined by employing the iterative feedback tuning approach to minimize tracking errors during forward dynamics simulation. Simultaneously, an inverse-dynamics-based optimization was employed to compute a set of desired musculotendon forces in the closed-loop simulation to resolve muscle redundancy. Quantitative comparisons of the simulation results with the experimental measurements and the reference muscles' activities illustrate the accuracy and efficiency of the proposed method during the stable ascending simulation.

  16. Steam Locomotives: a forgotten era

    African Journals Online (AJOL)

    The boiler was not armoured as the idea was that it was bullet proof. The locomotives were arranged into groups of five and for each group there was an engine as standby. As far as can be ascertained, locomotive No 537 was never armoured, but did work draw trains and freight trains during the Anglo-Boer War too.

  17. Water surface locomotion in tropical canopy ants.

    Science.gov (United States)

    Yanoviak, S P; Frederick, D N

    2014-06-15

    Upon falling onto the water surface, most terrestrial arthropods helplessly struggle and are quickly eaten by aquatic predators. Exceptions to this outcome mostly occur among riparian taxa that escape by walking or swimming at the water surface. Here we document sustained, directional, neustonic locomotion (i.e. surface swimming) in tropical arboreal ants. We dropped 35 species of ants into natural and artificial aquatic settings in Peru and Panama to assess their swimming ability. Ten species showed directed surface swimming at speeds >3 body lengths s(-1), with some swimming at absolute speeds >10 cm s(-1). Ten other species exhibited partial swimming ability characterized by relatively slow but directed movement. The remaining species showed no locomotory control at the surface. The phylogenetic distribution of swimming among ant genera indicates parallel evolution and a trend toward negative association with directed aerial descent behavior. Experiments with workers of Odontomachus bauri showed that they escape from the water by directing their swimming toward dark emergent objects (i.e. skototaxis). Analyses of high-speed video images indicate that Pachycondyla spp. and O. bauri use a modified alternating tripod gait when swimming; they generate thrust at the water surface via synchronized treading and rowing motions of the contralateral fore and mid legs, respectively, while the hind legs provide roll stability. These results expand the list of facultatively neustonic terrestrial taxa to include various species of tropical arboreal ants. © 2014. Published by The Company of Biologists Ltd.

  18. Leg lengthening - slideshow

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/presentations/100127.htm Leg lengthening - series—Indications To use the sharing features ... with lengthening procedures are the bones of the leg, the tibia and the femur. Surgical treatment may ...

  19. Arterial bypass leg - slideshow

    Science.gov (United States)

    ... medlineplus.gov/ency/presentations/100155.htm Arterial bypass leg - series—Normal anatomy To use the sharing features ... Overview The arteries which supply blood to the leg originate from the aorta and iliac vessels. Review ...

  20. Leg lengthening and shortening

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002965.htm Leg lengthening and shortening To use the sharing features on this page, please enable JavaScript. Leg lengthening and shortening are types of surgery to ...

  1. Synthesis of digital locomotive receiver of automatic locomotive signaling

    Directory of Open Access Journals (Sweden)

    K. V. Goncharov

    2013-02-01

    Full Text Available Purpose. Automatic locomotive signaling of continuous type with a numeric coding (ALSN has several disadvantages: a small number of signal indications, low noise stability, high inertia and low functional flexibility. Search for new and more advanced methods of signal processing for automatic locomotive signaling, synthesis of the noise proof digital locomotive receiver are essential. Methodology. The proposed algorithm of detection and identification locomotive signaling codes is based on the definition of mutual correlations of received oscillation and reference signals. For selecting threshold levels of decision element the following criterion has been formulated: the locomotive receiver should maximum set the correct solution for a given probability of dangerous errors. Findings. It has been found that the random nature of the ALSN signal amplitude does not affect the detection algorithm. However, the distribution law and numeric characteristics of signal amplitude affect the probability of errors, and should be considered when selecting a threshold levels According to obtained algorithm of detection and identification ALSN signals the digital locomotive receiver has been synthesized. It contains band pass filter, peak limiter, normalizing amplifier with automatic gain control circuit, analog to digital converter and digital signal processor. Originality. The ALSN system is improved by the way of the transfer of technical means to modern microelectronic element base, more perfect methods of detection and identification codes of locomotive signaling are applied. Practical value. Use of digital technology in the construction of the locomotive receiver ALSN will expand its functionality, will increase the noise immunity and operation stability of the locomotive signal system in conditions of various destabilizing factors.

  2. Skipping on uneven ground: trailing leg adjustments simplify control and enhance robustness

    Science.gov (United States)

    2018-01-01

    It is known that humans intentionally choose skipping in special situations, e.g. when descending stairs or when moving in environments with lower gravity than on Earth. Although those situations involve uneven locomotion, the dynamics of human skipping on uneven ground have not yet been addressed. To find the reasons that may motivate this gait, we combined experimental data on humans with numerical simulations on a bipedal spring-loaded inverted pendulum model (BSLIP). To drive the model, the following parameters were estimated from nine subjects skipping across a single drop in ground level: leg lengths at touchdown, leg stiffness of both legs, aperture angle between legs, trailing leg angle at touchdown (leg landing first after flight phase), and trailing leg retraction speed. We found that leg adjustments in humans occur mostly in the trailing leg (low to moderate leg retraction during swing phase, reduced trailing leg stiffness, and flatter trailing leg angle at lowered touchdown). When transferring these leg adjustments to the BSLIP model, the capacity of the model to cope with sudden-drop perturbations increased. PMID:29410879

  3. Foot, leg, and ankle swelling

    Science.gov (United States)

    Swelling of the ankles - feet - legs; Ankle swelling; Foot swelling; Leg swelling; Edema - peripheral; Peripheral edema ... Foot, leg, and ankle swelling is common when the person also: Is overweight Has a blood clot in the leg Is older Has ...

  4. Self-improving biped locomotion

    Science.gov (United States)

    Teixeira, C.; Costa, L.; Santos, C.

    2013-10-01

    An approach addressing biped locomotion is here introduced. Central Pattern Generators (CPGs) and Dynamic Movement Primitives (DMPs) were combined to easily produce complex trajectories for the joints of a simulated DARwIn-OP. Policy Learning by Weighting Exploration with the Returns (PoWER) was implemented to improve the robot's locomotion through variation of the DMP's parameters. Maximization of the DARwIn-OP's frontal velocity was addressed and results show a velocity improvement of 213%. The results are very promising and demonstrate the approach's flexibility at generating new trajectories for locomotion.

  5. Neural Control and Adaptive Neural Forward Models for Insect-like, Energy-Efficient, and Adaptable Locomotion of Walking Machines

    DEFF Research Database (Denmark)

    Manoonpong, Poramate; Parlitz, Ulrich; Wörgötter, Florentin

    2013-01-01

    basic rhythmic motions which are shaped by sensory feedback while internal models are used for sensory prediction and state estimations. According to this concept, we present here adaptive neural locomotion control consisting of a CPG mechanism with neuromodulation and local leg control mechanisms based...... on sensory feedback and adaptive neural forward models with efference copies. This neural closed-loop controller enables a walking machine to perform a multitude of different walking patterns including insect-like leg movements and gaits as well as energy-efficient locomotion. In addition, the forward models...... that the employed embodied neural closed-loop system can be a powerful way for developing robust and adaptable machines....

  6. Multiple Decoupled CPGs with Local Sensory Feedback for Adaptive Locomotion Behaviors of Bio-inspired Walking Robots

    DEFF Research Database (Denmark)

    Shaker Barikhan, Subhi; Wörgötter, Florentin; Manoonpong, Poramate

    2014-01-01

    and the environment through local sensory feedback of each leg. Simulation results show that this bio-inspired approach generates self-organizing emergent locomotion allowing the robot to adaptively form regular patterns, to stably walk while pushing an object with its front legs or performing multiple stepping......Walking animals show versatile locomotion. They can also adapt their movement according to the changes of their morphology and the environmental conditions. These emergent properties are realized by biomechanics, distributed central pattern generators (CPGs), local sensory feedback...

  7. Adaptive control strategies for interlimb coordination in legged robots

    DEFF Research Database (Denmark)

    Aoi, Shinya; Manoonpong, Poramate; Ambe, Yuichi

    2017-01-01

    for legged robots induced by various factors (locomotion speed, environmental situation, body properties, and task). In addition, we show characteristic properties of adaptive interlimb coordination, such as gait hysteresis and different time-scale adaptations. We also discuss the underlying mechanisms......Walking animals produce adaptive interlimb coordination during locomotion in accordance with their situation. Interlimb coordination is generated through the dynamic interactions of the neural system, the musculoskeletal system, and the environment, although the underlying mechanisms remain unclear....... Recently, investigations of the adaptationmechanisms of living beings have attracted attention, and bio-inspired control systems based on neurophysiological findings regarding sensorimotor interactions are being developed for legged robots. In this review, we introduce adaptive interlimb coordination...

  8. Generalizing the Hop: Object-Level Programming for Legged Motion

    Science.gov (United States)

    1990-08-01

    1989. 4. J. Hodgins, J. Koechling, and M. H. Raibert, "Running experiments with a planar biped ," in The 3rd International Symposium on Robotics ...controlling a hopping robot . The approach focuses on the interaction between the hopper and its surroundings at points of con- tact. It is only through...locomotion of legged robots . Walking, running, and hopping are distinguished from most conventional robot tasks in several respects. A stationary robot

  9. Fundamentals of soft robot locomotion

    OpenAIRE

    Calisti, M.; Picardi, G.; Laschi, C.

    2017-01-01

    Soft robotics and its related technologies enable robot abilities in several robotics domains including, but not exclusively related to, manipulation, manufacturing, human���robot interaction and locomotion. Although field applications have emerged for soft manipulation and human���robot interaction, mobile soft robots appear to remain in the research stage, involving the somehow conflictual goals of having a deformable body and exerting forces on the environment to achieve locomotion. This p...

  10. Neural Control and Adaptive Neural Forward Models for Insect-like, Energy-Efficient, and Adaptable Locomotion of Walking Machines

    Directory of Open Access Journals (Sweden)

    Poramate eManoonpong

    2013-02-01

    Full Text Available Living creatures, like walking animals, have found fascinating solutions for the problem of locomotion control. Their movements show the impression of elegance including versatile, energy-efficient, and adaptable locomotion. During the last few decades, roboticists have tried to imitate such natural properties with artificial legged locomotion systems by using different approaches including machine learning algorithms, classical engineering control techniques, and biologically-inspired control mechanisms. However, their levels of performance are still far from the natural ones. By contrast, animal locomotion mechanisms seem to largely depend not only on central mechanisms (central pattern generators, CPGs and sensory feedback (afferent-based control but also on internal forward models (efference copies. They are used to a different degree in different animals. Generally, CPGs organize basic rhythmic motions which are shaped by sensory feedback while internal models are used for sensory prediction and state estimations. According to this concept, we present here adaptive neural locomotion control consisting of a CPG mechanism with neuromodulation and local leg control mechanisms based on sensory feedback and adaptive neural forward models with efference copies. This neural closed-loop controller enables a walking machine to perform a multitude of different walking patterns including insect-like leg movements and gaits as well as energy-efficient locomotion. In addition, the forward models allow the machine to autonomously adapt its locomotion to deal with a change of terrain, losing of ground contact during stance phase, stepping on or hitting an obstacle during swing phase, leg damage, and even to promote cockroach-like climbing behavior. Thus, the results presented here show that the employed embodied neural closed-loop system can be a powerful way for developing robust and adaptable machines.

  11. Profile and genetic parameters of dairy cattle locomotion score and lameness across lactation.

    Science.gov (United States)

    Kougioumtzis, A; Valergakis, G E; Oikonomou, G; Arsenos, G; Banos, G

    2014-01-01

    have fewer locomotion and lameness issues. Negative (favourable) phenotypic correlations between first lactation weekly locomotion score/lameness and milk yield averaged ���0.27 and ���0.17, respectively, and were attributed to management factors. Also a phenotypic correlation between lameness and conception rate of ���0.19 indicated that lame cows were associated with lower success at conceiving. First-lactation daughter locomotion score and/or lameness predictions from sires��� estimated breeding values for conformation traits revealed a significant linear effect of rear leg side view, rear leg rear view, overall conformation, body condition score and locomotion, and a quadratic effect of foot angle.

  12. Spontaneous Symmetry-Breaking in a Network Model for Quadruped Locomotion

    Science.gov (United States)

    Stewart, Ian

    2017-12-01

    Spontaneous symmetry-breaking proves a mechanism for pattern generation in legged locomotion of animals. The basic timing patterns of animal gaits are produced by a network of spinal neurons known as a Central Pattern Generator (CPG). Animal gaits are primarily characterized by phase differences between leg movements in a periodic gait cycle. Many different gaits occur, often having spatial or spatiotemporal symmetries. A natural way to explain gait patterns is to assume that the CPG is symmetric, and to classify the possible symmetry-breaking periodic motions. Pinto and Golubitsky have discussed a four-node model CPG network for biped gaits with ℤ2 × ℤ2 symmetry, classifying the possible periodic states that can arise. A more specific rate model with this structure has been analyzed in detail by Stewart. Here we extend these methods to quadruped gaits, using an eight-node network with ℤ4 × ℤ2 symmetry proposed by Golubitsky and coworkers. We formulate a rate model and calculate how the first steady or Hopf bifurcation depends on its parameters, which represent four connection strengths. The calculations involve a distinction between “real” gaits with one or two phase shifts (pronk, bound, pace, trot) and “complex” gaits with four phase shifts (forward and reverse walk, forward and reverse buck). The former correspond to real eigenvalues of the connection matrix, the latter to complex conjugate pairs. The partition of parameter space according to the first bifurcation, ignoring complex gaits, is described explicitly. The complex gaits introduce further complications, not yet fully understood. All eight gaits can occur as the first bifurcation from a fully synchronous equilibrium, for suitable parameters, and numerical simulations indicate that they can be asymptotically stable.

  13. Venous leg ulcers.

    Science.gov (United States)

    Nelson, E Andrea; Adderley, Una

    2016-01-15

    Leg ulcers usually occur secondary to venous reflux or obstruction, but 20% of people with leg ulcers have arterial disease, with or without venous disorders. Between 1.5 and 3.0 in 1000 people have active leg ulcers. Prevalence increases with age to about 20 in 1000 people aged over 80 years. We conducted a systematic overview, aiming to answer the following clinical questions: What are the effects of treatments for venous leg ulcers? What are the effects of organisational interventions for venous leg ulcers? What are the effects of advice about self-help interventions in people receiving usual care for venous leg ulcers? What are the effects of interventions to prevent recurrence of venous leg ulcers? We searched: Medline, Embase, The Cochrane Library, and other important databases up to March 2014 (Clinical Evidence overviews are updated periodically; please check our website for the most up-to-date version of this overview). At this update, searching of electronic databases retrieved 116 studies. After deduplication and removal of conference abstracts, 63 records were screened for inclusion in the overview. Appraisal of titles and abstracts led to the exclusion of 43 studies and the further review of 20 full publications. Of the 20 full articles evaluated, four systematic reviews were updated and four RCTs were added at this update. We performed a GRADE evaluation for 23 PICO combinations. In this systematic overview, we categorised the efficacy for 13 interventions based on information about the effectiveness and safety of advice to elevate leg, advice to keep leg active, compression stockings for prevention of recurrence, compression bandages and stockings to treat venous leg ulcers, laser treatment (low level), leg ulcer clinics, pentoxifylline, skin grafting, superficial vein surgery for prevention of recurrence, superficial vein surgery to treat venous leg ulcers, therapeutic ultrasound, and topical negative pressure.

  14. Dedicated Hippocampal Inhibitory Networks for Locomotion and Immobility.

    Science.gov (United States)

    Arriaga, Moises; Han, Edward B

    2017-09-20

    Network activity is strongly tied to animal movement; however, hippocampal circuits selectively engaged during locomotion or immobility remain poorly characterized. Here we examined whether distinct locomotor states are encoded differentially in genetically defined classes of hippocampal interneurons. To characterize the relationship between interneuron activity and movement, we used in vivo , two-photon calcium imaging in CA1 of male and female mice, as animals performed a virtual-reality (VR) track running task. We found that activity in most somatostatin-expressing and parvalbumin-expressing interneurons positively correlated with locomotion. Surprisingly, nearly one in five somatostatin or one in seven parvalbumin interneurons were inhibited during locomotion and activated during periods of immobility. Anatomically, the somata of somatostatin immobility-activated neurons were smaller than those of movement-activated neurons. Furthermore, immobility-activated interneurons were distributed across cell layers, with somatostatin-expressing cells predominantly in stratum oriens and parvalbumin-expressing cells mostly in stratum pyramidale. Importantly, each cell's correlation between activity and movement was stable both over time and across VR environments. Our findings suggest that hippocampal interneuronal microcircuits are preferentially active during either movement or immobility periods. These inhibitory networks may regulate information flow in "labeled lines" within the hippocampus to process information during distinct behavioral states. SIGNIFICANCE STATEMENT The hippocampus is required for learning and memory. Movement controls network activity in the hippocampus but it's unclear how hippocampal neurons encode movement state. We investigated neural circuits active during locomotion and immobility and found interneurons were selectively active during movement or stopped periods, but not both. Each cell's response to locomotion was consistent across time

  15. Lyden-af-Leg

    DEFF Research Database (Denmark)

    Toft, Herdis

    Præsentation af seniorforsker-projekt Lyden-af-Leg i et traderingsperspektiv og med indledende fokus på YouTube som traderings-platform.......Præsentation af seniorforsker-projekt Lyden-af-Leg i et traderingsperspektiv og med indledende fokus på YouTube som traderings-platform....

  16. Jumping robots: a biomimetic solution to locomotion across rough terrain.

    Science.gov (United States)

    Armour, Rhodri; Paskins, Keith; Bowyer, Adrian; Vincent, Julian; Megill, William; Bomphrey, Richard

    2007-09-01

    This paper introduces jumping robots as a means to traverse rough terrain; such terrain can pose problems for traditional wheeled, tracked and legged designs. The diversity of jumping mechanisms found in nature is explored to support the theory that jumping is a desirable ability for a robot locomotion system to incorporate, and then the size-related constraints are determined from first principles. A series of existing jumping robots are presented and their performance summarized. The authors present two new biologically inspired jumping robots, Jollbot and Glumper, both of which incorporate additional locomotion techniques of rolling and gliding respectively. Jollbot consists of metal hoop springs forming a 300 mm diameter sphere, and when jumping it raises its centre of gravity by 0.22 m and clears a height of 0.18 m. Glumper is of octahedral shape, with four 'legs' that each comprise two 500 mm lengths of CFRP tube articulating around torsion spring 'knees'. It is able to raise its centre of gravity by 1.60 m and clears a height of 1.17 m. The jumping performance of the jumping robot designs presented is discussed and compared against some specialized jumping animals. Specific power output is thought to be the performance-limiting factor for a jumping robot, which requires the maximization of the amount of energy that can be stored together with a minimization of mass. It is demonstrated that this can be achieved through optimization and careful materials selection.

  17. GABAergic inhibition of leg motoneurons is required for normal walking behavior in freely moving Drosophila

    Science.gov (United States)

    Gowda, Swetha B. M.; Paranjpe, Pushkar D.; Reddy, O. Venkateswara; Thiagarajan, Devasena; Palliyil, Sudhir; Reichert, Heinrich

    2018-01-01

    Walking is a complex rhythmic locomotor behavior generated by sequential and periodical contraction of muscles essential for coordinated control of movements of legs and leg joints. Studies of walking in vertebrates and invertebrates have revealed that premotor neural circuitry generates a basic rhythmic pattern that is sculpted by sensory feedback and ultimately controls the amplitude and phase of the motor output to leg muscles. However, the identity and functional roles of the premotor interneurons that directly control leg motoneuron activity are poorly understood. Here we take advantage of the powerful genetic methodology available in Drosophila to investigate the role of premotor inhibition in walking by genetically suppressing inhibitory input to leg motoneurons. For this, we have developed an algorithm for automated analysis of leg motion to characterize the walking parameters of wild-type flies from high-speed video recordings. Further, we use genetic reagents for targeted RNAi knockdown of inhibitory neurotransmitter receptors in leg motoneurons together with quantitative analysis of resulting changes in leg movement parameters in freely walking Drosophila. Our findings indicate that targeted down-regulation of the GABAA receptor Rdl (Resistance to Dieldrin) in leg motoneurons results in a dramatic reduction of walking speed and step length without the loss of general leg coordination during locomotion. Genetically restricting the knockdown to the adult stage and subsets of motoneurons yields qualitatively identical results. Taken together, these findings identify GABAergic premotor inhibition of motoneurons as an important determinant of correctly coordinated leg movements and speed of walking in freely behaving Drosophila. PMID:29440493

  18. Reconstruction of human swing leg motion with passive biarticular muscle models.

    Science.gov (United States)

    Ahmad Sharbafi, Maziar; Mohammadi Nejad Rashty, Aida; Rode, Christian; Seyfarth, Andre

    2017-04-01

    Template models, which are utilized to demonstrate general aspects in human locomotion, mostly investigate stance leg operation. The goal of this paper is presenting a new conceptual walking model benefiting from swing leg dynamics. Considering a double pendulum equipped with combinations of biarticular springs for the swing leg beside spring-mass (SLIP) model for the stance leg, a novel SLIP-based model, is proposed to explain human-like leg behavior in walking. The action of biarticular muscles in swing leg motion helps represent human walking features, like leg retraction, ground reaction force and generating symmetric walking patterns, in simulations. In order to stabilize the motion by the proposed passive structure, swing leg biarticular muscle parameters such as lever arm ratios, stiffnesses and rest lengths need to be properly adjusted. Comparison of simulation results with human experiments shows the ability of the proposed model in replicating kinematic and kinetic behavior of both stance and swing legs as well as biarticular thigh muscle force of the swing leg. This substantiates the important functional role of biarticular muscles in leg swing. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Fundamentals of soft robot locomotion.

    Science.gov (United States)

    Calisti, M; Picardi, G; Laschi, C

    2017-05-01

    Soft robotics and its related technologies enable robot abilities in several robotics domains including, but not exclusively related to, manipulation, manufacturing, human-robot interaction and locomotion. Although field applications have emerged for soft manipulation and human-robot interaction, mobile soft robots appear to remain in the research stage, involving the somehow conflictual goals of having a deformable body and exerting forces on the environment to achieve locomotion. This paper aims to provide a reference guide for researchers approaching mobile soft robotics, to describe the underlying principles of soft robot locomotion with its pros and cons, and to envisage applications and further developments for mobile soft robotics. © 2017 The Author(s).

  20. Leg disorders in broiler chickens: prevalence, risk factors and prevention.

    Directory of Open Access Journals (Sweden)

    Toby G Knowles

    Full Text Available Broiler (meat chickens have been subjected to intense genetic selection. In the past 50 years, broiler growth rates have increased by over 300% (from 25 g per day to 100 g per day. There is growing societal concern that many broiler chickens have impaired locomotion or are even unable to walk. Here we present the results of a comprehensive survey of commercial flocks which quantifies the risk factors for poor locomotion in broiler chickens. We assessed the walking ability of 51,000 birds, representing 4.8 million birds within 176 flocks. We also obtained information on approximately 150 different management factors associated with each flock. At a mean age of 40 days, over 27.6% of birds in our study showed poor locomotion and 3.3% were almost unable to walk. The high prevalence of poor locomotion occurred despite culling policies designed to remove severely lame birds from flocks. We show that the primary risk factors associated with impaired locomotion and poor leg health are those specifically associated with rate of growth. Factors significantly associated with high gait score included the age of the bird (older birds, visit (second visit to same flock, bird genotype, not feeding whole wheat, a shorter dark period during the day, higher stocking density at the time of assessment, no use of antibiotic, and the use of intact feed pellets. The welfare implications are profound. Worldwide approximately 2 x 10(10 broilers are reared within similar husbandry systems. We identify a range of management factors that could be altered to reduce leg health problems, but implementation of these changes would be likely to reduce growth rate and production. A debate on the sustainability of current practice in the production of this important food source is required.

  1. Relation between observed locomotion traits and locomotion score in dairy cows

    NARCIS (Netherlands)

    Schlageter Tello, A.A.; Bokkers, E.A.M.; Groot Koerkamp, P.W.G.; Hertem, van T.; Viazzi, S.; Lokhorst, Kees

    2015-01-01

    Lameness is still an important problem in modern dairy farming. Human observation of locomotion, by looking at different traits in one go, is used in practice to assess locomotion. The objectives of this article were to determine which individual locomotion traits are most related to locomotion

  2. In Pipe Robot with Hybrid Locomotion System

    Directory of Open Access Journals (Sweden)

    Cristian Miclauş

    2015-06-01

    Full Text Available The first part of the paper covers aspects concerning in pipe robots and their components, such as hybrid locomotion systems and the adapting mechanisms used. The second part describes the inspection robot that was developed, which combines tracked and wheeled locomotion (hybrid locomotion. The end of the paper presents the advantages and disadvantages of the proposed robot.

  3. Locomotive monitoring system using wireless sensor networks

    CSIR Research Space (South Africa)

    Croucamp, PL

    2014-07-01

    Full Text Available Theft of cables used for powering a locomotive not only stops the train from functioning but also paralyzes the signalling and monitoring system. This means that information on certain locomotive's cannot be passed onto other locomotives which may...

  4. Towards Development of Robotic Aid for Rehabilitation of Locomotion-Impaired Subjects

    Science.gov (United States)

    Bejczy, Antal K.

    2000-01-01

    Manual assistance of therapists to help movement of legs of spinal cord injured (SCI) subjects during stepping on a treadmill for locomotion rehabilitation has severe economic and technical limitations. Scientists at the Department of Physiological Science at the University of California Los Angeles (UCLA) and roboticists at the Jet Propulsion Laboratory (JPL) initiated a joint effort to develop a robotic mechanism capable of performing controlled motions equivalent to the arm and hand motions of therapists assisting the stepping of locomotion impaired subjects on a treadmill, while the subjects' body weight is partially supported by an overhead harness. A first necessary technical step towards this development is to measure and understand the kinematics and dynamics of the therapists' arm and hand motions as they are reflected on the subjects' leg movement. This paper describes an initial measurement system developed for this purpose together with the related measurement results, and outlines the planned future technical work.

  5. Fuzzy-logic-based hybrid locomotion mode classification for an active pelvis orthosis: Preliminary results.

    Science.gov (United States)

    Yuan, Kebin; Parri, Andrea; Yan, Tingfang; Wang, Long; Munih, Marko; Vitiello, Nicola; Wang, Qining

    2015-01-01

    In this paper, we present a fuzzy-logic-based hybrid locomotion mode classification method for an active pelvis orthosis. Locomotion information measured by the onboard hip joint angle sensors and the pressure insoles is used to classify five locomotion modes, including two static modes (sitting, standing still), and three dynamic modes (level-ground walking, ascending stairs, and descending stairs). The proposed method classifies these two kinds of modes first by monitoring the variation of the relative hip joint angle between the two legs within a specific period. Static states are then classified by the time-based absolute hip joint angle. As for dynamic modes, a fuzzy-logic based method is proposed for the classification. Preliminary experimental results with three able-bodied subjects achieve an off-line classification accuracy higher than 99.49%.

  6. Bioinspired legged-robot based on large deformation of flexible skeleton

    International Nuclear Information System (INIS)

    Mayyas, Mohammad

    2014-01-01

    In this article we present STARbot, a bioinspired legged robot capable of multiple locomotion modalities by using large deformation of its skeleton. We construct STARbot by using origami-style folding of flexible laminates. The long-term goal is to provide a robotic platform with maximum mobility on multiple surfaces. This paper particularly studies the quasistatic model of STARbot’s leg under different conditions. We describe the large elastic deformation of a leg under external force, payload, and friction by using a set of non-dimensional, nonlinear approximate equations. We developed a test mechanism that models the motion of a leg in STARbot. We augmented several foot shapes and then tested them on soft to rough grounds. Both simulation and experimental findings were in good agreement. We utilized the model to develop several scales of tri and quad STARbot. We demonstrated the capability of these robots to locomote by combining their leg deformations with their foot motions. The combination provided a design platform for an active suspension STARbot with controlled foot locomotion. This included the ability of STARbot to change size, run over obstacles, walk and slide. Furthermore, in this paper we discuss a cost effective manufacturing and production method for manufacturing STARbot. (paper)

  7. Summertime blues? A re-examination of the seasonality of web searches for restless legs and leg cramps.

    Science.gov (United States)

    O'Keeffe, Shaun T

    2017-09-01

    Studies that examined Internet searches for restless legs and leg cramps have found a strong seasonal effect with peaks in summer and troughs in winter months. The present study used an econometric approach to examine the seasonality of such searches in greater detail. Monthly relative search volumes for 'restless legs' and 'leg cramps' from 2004 to March 2017 in the United Kingdom (UK) and Australia were obtained from Google Trends. Average percentage change from winter to summer months was examined. The TRAMO-SEATS procedure from the DEMETRA statistical software was used to decompose the data into trend, seasonal and noise components and to determine whether a combined seasonality test was positive. There were substantial percentage increases in Google Trends searches between winter and summer months regarding restless legs in the UK (median increase 46%) and Australia (33%) and regarding leg cramps in the UK (95%) and Australia (50%). However, the combined seasonality test was positive only for leg cramps and not for restless legs in both countries: although there was significant stable seasonality in restless legs searches, this was outweighed by substantial moving seasonality and noise components. Examination of average percentage increase in search volume from winter to summer exaggerates the degree of seasonality. Seasonal effects for restless legs searches are non-significant when the trend and noise components of the data are considered, although this does not exclude a clinical significance for the identified stable seasonality. Significant seasonality, with a summer peak, is present for leg cramps searches and suggests an increase in the incidence or severity of leg cramps in summer. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Adaptive Control Strategies for Interlimb Coordination in Legged Robots: A Review

    Directory of Open Access Journals (Sweden)

    Shinya Aoi

    2017-08-01

    Full Text Available Walking animals produce adaptive interlimb coordination during locomotion in accordance with their situation. Interlimb coordination is generated through the dynamic interactions of the neural system, the musculoskeletal system, and the environment, although the underlying mechanisms remain unclear. Recently, investigations of the adaptation mechanisms of living beings have attracted attention, and bio-inspired control systems based on neurophysiological findings regarding sensorimotor interactions are being developed for legged robots. In this review, we introduce adaptive interlimb coordination for legged robots induced by various factors (locomotion speed, environmental situation, body properties, and task. In addition, we show characteristic properties of adaptive interlimb coordination, such as gait hysteresis and different time-scale adaptations. We also discuss the underlying mechanisms and control strategies to achieve adaptive interlimb coordination and the design principle for the control system of legged robots.

  9. RESTLESS LEGS SYNDROME

    Directory of Open Access Journals (Sweden)

    Dmitriy Valer'evich Artem'ev

    2009-01-01

    Full Text Available The paper describes the epidemiology, etiology, pathogenesis, clinical picture, diagnosis, differential diagnosis, and treatment of restless legs syndrome. Recommendations are given how to choose therapeutic modalities and drugs in relation to different factors.

  10. Restless legs syndrome.

    Science.gov (United States)

    Venkateshiah, Saiprakash B; Ioachimescu, Octavian C

    2015-07-01

    Restless legs syndrome is a common sensorimotor disorder characterized by an urge to move, and associated with uncomfortable sensations in the legs (limbs). Restless legs syndrome can lead to sleep-onset or sleep-maintenance insomnia, and occasionally excessive daytime sleepiness, all leading to significant morbidity. Brain iron deficiency and dopaminergic neurotransmission abnormalities play a central role in the pathogenesis of this disorder, along with other nondopaminergic systems, although the exact mechanisms are still. Intensive care unit patients are especially vulnerable to have unmasking or exacerbation of restless legs syndrome because of sleep deprivation, circadian rhythm disturbance, immobilization, iron deficiency, and use of multiple medications that can antagonize dopamine. Published by Elsevier Inc.

  11. Three-dimensional topographies of water surface dimples formed by superhydrophobic water strider legs

    Science.gov (United States)

    Yin, W.; Zheng, Y. L.; Lu, H. Y.; Zhang, X. J.; Tian, Y.

    2016-10-01

    A water strider has a remarkable capability to stand and walk freely on water. Supporting forces of a water strider and a bionic robot have been calculated from the side view of pressed depth of legs to reconstruct the water surface dimples. However, in situ measurements of the multiple leg forces and significantly small leg/water contact dimples have not been realized yet. In this study, a shadow method was proposed to reconstruct the in situ three-dimensional topographies of leg/water contact dimples and their corresponding supporting forces. Results indicated that the supporting forces were affected by the depth, width, and length of the dimple, and that the maximum dimple depth was not proportional to the supporting forces. The shadow method also has advantages in disclosing tiny supporting force of legs in their subtle actions. These results are helpful for understanding the locomotion principles of water-walking insects and the design of biomimetic aquatic devices.

  12. Shaping leg muscles in Drosophila: role of ladybird, a conserved regulator of appendicular myogenesis.

    Directory of Open Access Journals (Sweden)

    Tariq Maqbool

    Full Text Available Legs are locomotor appendages used by a variety of evolutionarily distant vertebrates and invertebrates. The primary biological leg function, locomotion, requires the formation of a specialised appendicular musculature. Here we report evidence that ladybird, an orthologue of the Lbx1 gene recognised as a hallmark of appendicular myogenesis in vertebrates, is expressed in leg myoblasts, and regulates the shape, ultrastructure and functional properties of leg muscles in Drosophila. Ladybird expression is progressively activated in myoblasts associated with the imaginal leg disc and precedes that of the founder cell marker dumbfounded. The RNAi-mediated attenuation of ladybird expression alters properties of developing myotubes, impairing their ability to grow and interact with the internal tendons and epithelial attachment sites. It also affects sarcomeric ultrastructure, resulting in reduced leg muscle performance and impaired mobility in surviving flies. The over-expression of ladybird also results in an abnormal pattern of dorsally located leg muscles, indicating different requirements for ladybird in dorsal versus ventral muscles. This differential effect is consistent with the higher level of Ladybird in ventrally located myoblasts and with positive ladybird regulation by extrinsic Wingless signalling from the ventral epithelium. In addition, ladybird expression correlates with that of FGF receptor Heartless and the read-out of FGF signalling downstream of FGF. FGF signals regulate the number of leg disc associated myoblasts and are able to accelerate myogenic differentiation by activating ladybird, leading to ectopic muscle fibre formation. A key role for ladybird in leg myogenesis is further supported by its capacity to repress vestigial and to down-regulate the vestigial-governed flight muscle developmental programme. Thus in Drosophila like in vertebrates, appendicular muscles develop from a specialised pool of myoblasts expressing

  13. Shaping leg muscles in Drosophila: role of ladybird, a conserved regulator of appendicular myogenesis.

    Science.gov (United States)

    Maqbool, Tariq; Soler, Cedric; Jagla, Teresa; Daczewska, Malgorzata; Lodha, Neha; Palliyil, Sudhir; VijayRaghavan, K; Jagla, Krzysztof

    2006-12-27

    Legs are locomotor appendages used by a variety of evolutionarily distant vertebrates and invertebrates. The primary biological leg function, locomotion, requires the formation of a specialised appendicular musculature. Here we report evidence that ladybird, an orthologue of the Lbx1 gene recognised as a hallmark of appendicular myogenesis in vertebrates, is expressed in leg myoblasts, and regulates the shape, ultrastructure and functional properties of leg muscles in Drosophila. Ladybird expression is progressively activated in myoblasts associated with the imaginal leg disc and precedes that of the founder cell marker dumbfounded. The RNAi-mediated attenuation of ladybird expression alters properties of developing myotubes, impairing their ability to grow and interact with the internal tendons and epithelial attachment sites. It also affects sarcomeric ultrastructure, resulting in reduced leg muscle performance and impaired mobility in surviving flies. The over-expression of ladybird also results in an abnormal pattern of dorsally located leg muscles, indicating different requirements for ladybird in dorsal versus ventral muscles. This differential effect is consistent with the higher level of Ladybird in ventrally located myoblasts and with positive ladybird regulation by extrinsic Wingless signalling from the ventral epithelium. In addition, ladybird expression correlates with that of FGF receptor Heartless and the read-out of FGF signalling downstream of FGF. FGF signals regulate the number of leg disc associated myoblasts and are able to accelerate myogenic differentiation by activating ladybird, leading to ectopic muscle fibre formation. A key role for ladybird in leg myogenesis is further supported by its capacity to repress vestigial and to down-regulate the vestigial-governed flight muscle developmental programme. Thus in Drosophila like in vertebrates, appendicular muscles develop from a specialised pool of myoblasts expressing ladybird/Lbx1. The

  14. Venous leg ulcers.

    Science.gov (United States)

    Nelson, E Andrea

    2011-12-21

    Leg ulcers usually occur secondary to venous reflux or obstruction, but 20% of people with leg ulcers have arterial disease, with or without venous disorders. Between 1.5 and 3.0/1000 people have active leg ulcers. Prevalence increases with age to about 20/1000 in people aged over 80 years. We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of standard treatments, adjuvant treatments, and organisational interventions for venous leg ulcers? What are the effects of advice about self-help interventions in people receiving usual care for venous leg ulcers? What are the effects of interventions to prevent recurrence of venous leg ulcers? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2011 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We found 101 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. In this systematic review we present information relating to the effectiveness and safety of the following interventions: compression bandages and stockings, cultured allogenic (single or bilayer) skin replacement, debriding agents, dressings (cellulose, collagen, film, foam, hyaluronic acid-derived, semi-occlusive alginate), hydrocolloid (occlusive) dressings in the presence of compression, intermittent pneumatic compression, intravenous prostaglandin E1, larval therapy, laser treatment (low-level), leg ulcer clinics, multilayer elastic system, multilayer elastomeric (or non-elastomeric) high-compression regimens or bandages, oral treatments (aspirin, flavonoids, pentoxifylline, rutosides, stanozolol, sulodexide

  15. Scaling laws of aquatic locomotion

    Science.gov (United States)

    Sun, BoHua

    2017-10-01

    In recent years studies of aquatic locomotion have provided some remarkable insights into the many features of fish swimming performances. This paper derives a scaling relation of aquatic locomotion C D( Re)2 = ( Sw)2 and its corresponding log law and power law. For power scaling law, ( Sw)2 = β n Re 2-1/ n , which is valid within the full spectrum of the Reynolds number Re = UL/ν from low up to high, can simply be expressed as the power law of the Reynolds number Re and the swimming number Sw = ωAL/ν as Re ∝ ( Sw)σ, with σ = 2 for creeping flows, σ = 4=3 for laminar flows, σ = 10=9 and σ = 14=13 for turbulent flows. For log law this paper has derived the scaling law as Sw ∝ Re=(ln Re+1:287), which is even valid for a much wider range of the Reynolds number Re. Both power and log scaling relationships link the locomotory input variables that describe the swimmer's gait A; ω via the swimming number Sw to the locomotory output velocity U via the longitudinal Reynolds number Re, and reveal the secret input-output relationship of aquatic locomotion at different scales of the Reynolds number

  16. Emotion through locomotion: gender impact.

    Directory of Open Access Journals (Sweden)

    Samuel Krüger

    Full Text Available Body language reading is of significance for daily life social cognition and successful social interaction, and constitutes a core component of social competence. Yet it is unclear whether our ability for body language reading is gender specific. In the present work, female and male observers had to visually recognize emotions through point-light human locomotion performed by female and male actors with different emotional expressions. For subtle emotional expressions only, males surpass females in recognition accuracy and readiness to respond to happy walking portrayed by female actors, whereas females exhibit a tendency to be better in recognition of hostile angry locomotion expressed by male actors. In contrast to widespread beliefs about female superiority in social cognition, the findings suggest that gender effects in recognition of emotions from human locomotion are modulated by emotional content of actions and opposite actor gender. In a nutshell, the study makes a further step in elucidation of gender impact on body language reading and on neurodevelopmental and psychiatric deficits in visual social cognition.

  17. Adaptive leg coordination with a biologically inspired neurocontroller

    Science.gov (United States)

    Braught, Grant; Thomopoulos, Stelios C.

    1996-10-01

    Natural selection is responsible for the creation of robust and adaptive control systems. Nature's control systems are created only from primitive building blocks. Using insect neurophysiology as a guide, a neural architecture for leg coordination in a hexapod robot has been developed. Reflex chains and sensory feedback mechanisms from various insects and crustacea form the basis of a pattern generator for intra-leg coordination. The pattern generator contains neural oscillators which learn from sensory feedback to produce stepping patterns. Using sensory feedback as the source of learning information allows the pattern generator to adapt to changes in the leg dynamics due to internal or external causes. A coupling between six of the single leg pattern generators is used to produce the inter-leg coordination necessary to establish stable gaits.

  18. Locomotive biofuel study : preliminary study on the use and the effects of biodiesel in locomotives.

    Science.gov (United States)

    2014-05-01

    Section 404 of the Passenger Rail Investment and Improvement Act (PRIIA), 2008, mandated that the Federal Railroad : Administration (FRA) undertake a Locomotive Biofuel Study to investigate the feasibility of using biofuel blends as locomotive : engi...

  19. Dynamic stability of running: The effects of speed and leg amputations on the maximal Lyapunov exponent

    Energy Technology Data Exchange (ETDEWEB)

    Look, Nicole [Department of Applied Mathematics, University of Colorado Boulder, Boulder, Colorado 80309 (United States); Arellano, Christopher J.; Grabowski, Alena M.; Kram, Rodger [Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado 80309 (United States); McDermott, William J. [The Orthopedic Specialty Hospital, Murray, Utah 84107 (United States); Bradley, Elizabeth [Department of Computer Science, University of Colorado Boulder, Boulder, Colorado 80309, USA and Santa Fe Institute, Santa Fe, New Mexico 87501 (United States)

    2013-12-15

    In this paper, we study dynamic stability during running, focusing on the effects of speed, and the use of a leg prosthesis. We compute and compare the maximal Lyapunov exponents of kinematic time-series data from subjects with and without unilateral transtibial amputations running at a wide range of speeds. We find that the dynamics of the affected leg with the running-specific prosthesis are less stable than the dynamics of the unaffected leg and also less stable than the biological legs of the non-amputee runners. Surprisingly, we find that the center-of-mass dynamics of runners with two intact biological legs are slightly less stable than those of runners with amputations. Our results suggest that while leg asymmetries may be associated with instability, runners may compensate for this effect by increased control of their center-of-mass dynamics.

  20. Dynamic stability of running: The effects of speed and leg amputations on the maximal Lyapunov exponent

    International Nuclear Information System (INIS)

    Look, Nicole; Arellano, Christopher J.; Grabowski, Alena M.; Kram, Rodger; McDermott, William J.; Bradley, Elizabeth

    2013-01-01

    In this paper, we study dynamic stability during running, focusing on the effects of speed, and the use of a leg prosthesis. We compute and compare the maximal Lyapunov exponents of kinematic time-series data from subjects with and without unilateral transtibial amputations running at a wide range of speeds. We find that the dynamics of the affected leg with the running-specific prosthesis are less stable than the dynamics of the unaffected leg and also less stable than the biological legs of the non-amputee runners. Surprisingly, we find that the center-of-mass dynamics of runners with two intact biological legs are slightly less stable than those of runners with amputations. Our results suggest that while leg asymmetries may be associated with instability, runners may compensate for this effect by increased control of their center-of-mass dynamics

  1. Characteristics of undulatory locomotion in granular media

    OpenAIRE

    Peng, Zhiwei; Pak, On Shun; Elfring, Gwynn J.

    2015-01-01

    Undulatory locomotion is ubiquitous in nature and observed in different media, from the swimming of flagellated microorganisms in biological fluids, to the slithering of snakes on land, or the locomotion of sandfish lizards in sand. Despite the similarity in the undulating pattern, the swimming characteristics depend on the rheological properties of different media. Analysis of locomotion in granular materials is relatively less developed compared with fluids partially due to a lack of valida...

  2. Coupling of cytoskeleton functions for fibroblast locomotion

    DEFF Research Database (Denmark)

    Couchman, J R; Lenn, M; Rees, D A

    1985-01-01

    Using a chick cell phenotype specialised for locomotion with morphometric measurements made possible by modern instrumentation technology, we have reinvestigated motile functions in fibroblast locomotion. Quantitative analysis of rapid fluctuations in cell form and organelle distribution during l...... function of microtubules to direct the flow towards multiple foci on the leading edge, and so determine cell polarity. Such a mechanism of locomotion for fibroblasts has many features consistent with evidence for other cell types, especially amoebae and leukocytes....

  3. Modeling limbless locomotion using ADAMS software Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Limbless locomotion has the potential of meeting transportation requirements, particularly in challenging environments. Snakes can traverse a variety of surfaces...

  4. Gait Control for Redundant Legged Biped Robot at Constant Velocity and Constant Height of the Waist

    Science.gov (United States)

    Shima, Ryoichi; Haishi, Masahiko; Shibata, Masaaki

    In this paper, we propose a gait control method for redundant legged biped robot based on leg center of mass (COM) position control at constant velocity and constant height of the waist. The developed biped robot has redundant legs, which have 4 degree-of-freedoms (DOFs) on each in the saggital plane. The redundant DOF enables to move its leg tip position and its leg COM position independently. Therefore proposed robot has structural capability to control the leg COM position for keeping the projection of the total COM inside the support polygon without upper body motion. Such capability enables the stable static walk in the arbitrarily desired velocity and height of the waist motion. The validity of the proposed method for the static walk at constant velocity and constant height of the waist in the leg COM position control for redundant legged biped robot is confirmed by several results of simulation and experiment.

  5. Railroad and locomotive technology roadmap.

    Energy Technology Data Exchange (ETDEWEB)

    Stodolsky, F.; Gaines, L.; Energy Systems

    2003-02-24

    Railroads are important to the U.S. economy. They transport freight efficiently, requiring less energy and emitting fewer pollutants than other modes of surface transportation. While the railroad industry has steadily improved its fuel efficiency--by 16% over the last decade--more can, and needs to, be done. The ability of locomotive manufacturers to conduct research into fuel efficiency and emissions reduction is limited by the small number of locomotives manufactured annually. Each year for the last five years, the two North American locomotive manufacturers--General Electric Transportation Systems and the Electro-Motive Division of General Motors--have together sold about 800 locomotives in the United States. With such a small number of units over which research costs can be spread, outside help is needed to investigate all possible ways to reduce fuel usage and emissions. Because fuel costs represent a significant portion of the total operating costs of a railroad, fuel efficiency has always been an important factor in the design of locomotives and in the operations of a railroad. However, fuel efficiency has recently become even more critical with the introduction of strict emission standards by the U.S. Environmental Protection Agency, to be implemented in stages (Tiers 0, 1, and 2) between 2000 and 2005. Some of the technologies that could be employed to meet the emission standards may negatively affect fuel economy--by as much as 10-15% when emissions are reduced to Tier 1 levels. Lowering fuel economy by that magnitude would have a serious impact on the cost to the consumer of goods shipped by rail, on the competitiveness of the railroad industry, and on this country's dependence on foreign oil. Clearly, a joint government/industry R&D program is needed to help catalyze the development of advanced technologies that will substantially reduce locomotive engine emissions while also improving train system energy efficiency. DOE convened an industry

  6. Hybrid magnetic mechanism for active locomotion based on inchworm motion

    International Nuclear Information System (INIS)

    Kim, Sung Hoon; Hashi, Shuichiro; Ishiyama, Kazushi

    2013-01-01

    Magnetic robots have been studied in the past. Insect-type micro-robots are used in various biomedical applications; researchers have developed inchworm micro-robots for endoscopic use. A biological inchworm has a looping locomotion gait. However, most inchworm micro-robots depend on a general bending, or bellows, motion. In this paper, we introduce a new robotic mechanism using magnetic force and torque control in a rotating magnetic field for a looping gait. The proposed robot is controlled by the magnetic torque, attractive force, and body mechanisms (two stoppers, flexible body, and different frictional legs). The magnetic torque generates a general bending motion. In addition, the attractive force and body mechanisms produce the robot’s looping motion within a rotating magnetic field and without the use of an algorithm for field control. We verified the device’s performance and analyzed the motion through simulations and various experiments. The robot mechanism can be applied to active locomotion for various medical robots, such as wireless endoscopes. (technical note)

  7. An integrated neuromechanical model of insect locomotion

    Science.gov (United States)

    Kukillaya, Raghavendra

    We develop a biologically-plausible feedforward neuromechanical model for running insects that includes a simplified hexapedal leg geometry with agonist-antagonist muscle pairs actuating each leg joint. It is driven by a neural network modeling the central pattern generator (CPG) and the motoneurons which activate the muscles. This final goal is achieved in three stages. First, a relatively simple mechanical hexapedal model is constructed in which the joint torques are produced via actuated linear torsional springs with constant stiffness. In the second stage, this system is upgraded to a muscle-actuated hexapedal model in which each joint is actuated by a pair of agonist-antagonist Hill-type muscles. Muscles are driven by stylized action potentials that are characteristic of fast motoneurons, and modeled using an activation function and nonlinear length and shortening velocity dependence. In the final stage, the full neuromechanical model is obtained by integrating the above muscle-actuated hexapedal model with a CPG-motoneuron complex, feedforward input to the muscles now being supplied by action potentials from motoneurons. Restricting to dynamics in the horizontal plane and neglecting leg masses, we reduce the model (at each stage) to three degrees of freedom describing translational and yawing motions of the body. Collectively for all the models, parameter values are based on measurements from depressor motoneurons and muscles, and observations of kinematics and dynamics of the cockroach Blaberus discoidalis. Specifically, actuation inputs for the mechanical and muscle-actuated models are chosen to approximately achieve joint torques that are consistent with measured ground reaction forces. This is done by optimizing the time-dependent torque-free joint angles in the first model, and by optimizing motoneuronal outputs and muscle force levels in the second and third models. We show that the model (at each stage) has stable double-tripod gaits over the animal

  8. A neural circuitry that emphasizes spinal feedback generates diverse behaviours of human locomotion.

    Science.gov (United States)

    Song, Seungmoon; Geyer, Hartmut

    2015-08-15

    It is often assumed that central pattern generators, which generate rhythmic patterns without rhythmic inputs, play a key role in the spinal control of human locomotion. We propose a neural control model in which the spinal control generates muscle stimulations mainly through integrated reflex pathways with no central pattern generator. Using a physics-based neuromuscular human model, we show that this control network is sufficient to compose steady and transitional 3-D locomotion behaviours, including walking and running, acceleration and deceleration, slope and stair negotiation, turning, and deliberate obstacle avoidance. The results suggest feedback integration to be functionally more important than central pattern generation in human locomotion across behaviours. In addition, the proposed control architecture may serve as a guide in the search for the neurophysiological origin and circuitry of spinal control in humans. Neural networks along the spinal cord contribute substantially to generating locomotion behaviours in humans and other legged animals. However, the neural circuitry involved in this spinal control remains unclear. We here propose a specific circuitry that emphasizes feedback integration over central pattern generation. The circuitry is based on neurophysiologically plausible muscle-reflex pathways that are organized in 10 spinal modules realizing limb functions essential to legged systems in stance and swing. These modules are combined with a supraspinal control layer that adjusts the desired foot placements and selects the leg that is to transition into swing control during double support. Using physics-based simulation, we test the proposed circuitry in a neuromuscular human model that includes neural transmission delays, musculotendon dynamics and compliant foot-ground contacts. We find that the control network is sufficient to compose steady and transitional 3-D locomotion behaviours including walking and running, acceleration and

  9. The investigation of the locomotive boiler material

    International Nuclear Information System (INIS)

    Tucholski, Z.; Wasiak, J.; Bilous, W.; Hajewska, E.

    2006-01-01

    In the paper, the history of narrow-gauge railway system is described. The other information about the steam locomotive construction, as well as the technical regulations of its construction and exploitation are also done. The results of the studies of the locomotive boiler material are presented. (authors)

  10. 77 FR 21311 - Locomotive Safety Standards

    Science.gov (United States)

    2012-04-09

    ... final rule incorporates existing industry and engineering best practices related to locomotives and... retrospective review requirements of E.O. 13563, trends in locomotive operation, concern about the safe design... sub-assemblies of pneumatic valves, electronic controls and software (referred to as line replaceable...

  11. ORTHOPEDIC LEG BRACE

    Science.gov (United States)

    Myers, William Neil (Inventor)

    2005-01-01

    Knee braces generally have been rigid in both the knee bending direction and in the knee straightening direction unless a manually operated release is incorporated in them to allow the knee to bend. Desirably a braced knee joint should effectively duplicate the compound, complex, actions of a normal knee. The key to knee braces is the knee joint housing. The housing herein carries a number of cam action pawls. with teeth adapted to engage the internal teeth of a ratchet ring mounted in the housing. Cam action return springs and the shape of the cam action pawl teeth allow rotation of the ratchet ring in a leg straightening direction while still supporting a load. The leg can then be extended during walking while at the same time being prevented by the cam action pawls from buckling in the knee bending direction.

  12. Locomotor-Like Leg Movements Evoked by Rhythmic Arm Movements in Humans

    Science.gov (United States)

    Sylos-Labini, Francesca; Ivanenko, Yuri P.; MacLellan, Michael J.; Cappellini, Germana; Poppele, Richard E.; Lacquaniti, Francesco

    2014-01-01

    Motion of the upper limbs is often coupled to that of the lower limbs in human bipedal locomotion. It is unclear, however, whether the functional coupling between upper and lower limbs is bi-directional, i.e. whether arm movements can affect the lumbosacral locomotor circuitry. Here we tested the effects of voluntary rhythmic arm movements on the lower limbs. Participants lay horizontally on their side with each leg suspended in an unloading exoskeleton. They moved their arms on an overhead treadmill as if they walked on their hands. Hand-walking in the antero-posterior direction resulted in significant locomotor-like movements of the legs in 58% of the participants. We further investigated quantitatively the responses in a subset of the responsive subjects. We found that the electromyographic (EMG) activity of proximal leg muscles was modulated over each cycle with a timing similar to that of normal locomotion. The frequency of kinematic and EMG oscillations in the legs typically differed from that of arm oscillations. The effect of hand-walking was direction specific since medio-lateral arm movements did not evoke appreciably leg air-stepping. Using externally imposed trunk movements and biomechanical modelling, we ruled out that the leg movements associated with hand-walking were mainly due to the mechanical transmission of trunk oscillations. EMG activity in hamstring muscles associated with hand-walking often continued when the leg movements were transiently blocked by the experimenter or following the termination of arm movements. The present results reinforce the idea that there exists a functional neural coupling between arm and legs. PMID:24608249

  13. Locomotor-like leg movements evoked by rhythmic arm movements in humans.

    Directory of Open Access Journals (Sweden)

    Francesca Sylos-Labini

    Full Text Available Motion of the upper limbs is often coupled to that of the lower limbs in human bipedal locomotion. It is unclear, however, whether the functional coupling between upper and lower limbs is bi-directional, i.e. whether arm movements can affect the lumbosacral locomotor circuitry. Here we tested the effects of voluntary rhythmic arm movements on the lower limbs. Participants lay horizontally on their side with each leg suspended in an unloading exoskeleton. They moved their arms on an overhead treadmill as if they walked on their hands. Hand-walking in the antero-posterior direction resulted in significant locomotor-like movements of the legs in 58% of the participants. We further investigated quantitatively the responses in a subset of the responsive subjects. We found that the electromyographic (EMG activity of proximal leg muscles was modulated over each cycle with a timing similar to that of normal locomotion. The frequency of kinematic and EMG oscillations in the legs typically differed from that of arm oscillations. The effect of hand-walking was direction specific since medio-lateral arm movements did not evoke appreciably leg air-stepping. Using externally imposed trunk movements and biomechanical modelling, we ruled out that the leg movements associated with hand-walking were mainly due to the mechanical transmission of trunk oscillations. EMG activity in hamstring muscles associated with hand-walking often continued when the leg movements were transiently blocked by the experimenter or following the termination of arm movements. The present results reinforce the idea that there exists a functional neural coupling between arm and legs.

  14. An Adaptive Classification Strategy for Reliable Locomotion Mode Recognition

    Directory of Open Access Journals (Sweden)

    Ming Liu

    2017-09-01

    Full Text Available Algorithms for locomotion mode recognition (LMR based on surface electromyography and mechanical sensors have recently been developed and could be used for the neural control of powered prosthetic legs. However, the variations in input signals, caused by physical changes at the sensor interface and human physiological changes, may threaten the reliability of these algorithms. This study aimed to investigate the effectiveness of applying adaptive pattern classifiers for LMR. Three adaptive classifiers, i.e., entropy-based adaptation (EBA, LearnIng From Testing data (LIFT, and Transductive Support Vector Machine (TSVM, were compared and offline evaluated using data collected from two able-bodied subjects and one transfemoral amputee. The offline analysis indicated that the adaptive classifier could effectively maintain or restore the performance of the LMR algorithm when gradual signal variations occurred. EBA and LIFT were recommended because of their better performance and higher computational efficiency. Finally, the EBA was implemented for real-time human-in-the-loop prosthesis control. The online evaluation showed that the applied EBA effectively adapted to changes in input signals across sessions and yielded more reliable prosthesis control over time, compared with the LMR without adaptation. The developed novel adaptive strategy may further enhance the reliability of neurally-controlled prosthetic legs.

  15. Electric-Pneumatic Actuator: A New Muscle for Locomotion

    Directory of Open Access Journals (Sweden)

    Maziar Ahmad Sharbafi

    2017-10-01

    Full Text Available A better understanding of how actuator design supports locomotor function may help develop novel and more functional powered assistive devices or robotic legged systems. Legged robots comprise passive parts (e.g., segments, joints and connections which are moved in a coordinated manner by actuators. In this study, we propose a novel concept of a hybrid electric-pneumatic actuator (EPA as an enhanced variable impedance actuator (VIA. EPA is consisted of a pneumatic artificial muscle (PAM and an electric motor (EM. In contrast to other VIAs, the pneumatic artificial muscle (PAM within the EPA provides not only adaptable compliance, but also an additional powerful actuator with muscle-like properties, which can be arranged in different combinations (e.g., in series or parallel to the EM. The novel hybrid actuator shares the advantages of both integrated actuator types combining precise control of EM with compliant energy storage of PAM, which are required for efficient and adjustable locomotion. Experimental and simulation results based on the new dynamic model of PAM support the hypothesis that combination of the two actuators can improve efficiency (energy and peak power and performance, while does not increase control complexity and weight, considerably. Finally, the experiments on EPA adapted bipedal robot (knee joint of the BioBiped3 robot show improved efficiency of the actuator at different frequencies.

  16. Legāti

    OpenAIRE

    Segliņa, Aiga

    2010-01-01

    Autore teorētiski analizē legāta jēdzienu testamentārās mantošanas ietvaros un atspoguļo praktiska pētījuma rezultātus. Teorētiskā daļa apskata legāta nodibināšanas formu un spēkā esamību, tā iegūšanu un atraidīšanu, izpildi un zaudēšanu, novēlējuma robežas un aprobežojumus. Pētījums veikts aptaujas veidā ar mērķi noskaidrot, cik liela Latvijas iedzīvotāju daļa apzinās legāta nodrošinātās priekšrocības testamentārajā mantošanā. Apskatīts notāra neitralitātes jautājums attiecībā pret mantošana...

  17. High energy spectrogram with integrated prior knowledge for EMG-based locomotion classification.

    Science.gov (United States)

    Joshi, Deepak; Nakamura, Bryson H; Hahn, Michael E

    2015-05-01

    Electromyogram (EMG) signal representation is crucial in classification applications specific to locomotion and transitions. For a given signal, classification can be performed using discriminant functions or if-else rule sets, using learning algorithms derived from training examples. In the present work, a spectrogram based approach was developed to classify (EMG) signals for locomotion mode. Spectrograms for each muscle were calculated and summed to develop a histogram. If-else rules were used to classify test data based on a matching score. Prior knowledge of locomotion type reduced class space to exclusive locomotion modes. The EMG data were collected from seven leg muscles in a sample of able-bodied subjects while walking over ground (W), ascending stairs (SA) and the transition between (W-SA). Three muscles with least discriminating power were removed from the original data set to examine the effect on classification accuracy. Initial classification error was <20% across all modes, using leave one out cross validation. Use of prior knowledge reduced the average classification error to <11%. Removing three EMG channels decreased the classification accuracy by 10.8%, 24.3%, and 8.1% for W, W-SA, and SA respectively, and reduced computation time by 42.8%. This approach may be useful in the control of multi-mode assistive devices. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  18. FPGA implementation of a configurable neuromorphic CPG-based locomotion controller.

    Science.gov (United States)

    Barron-Zambrano, Jose Hugo; Torres-Huitzil, Cesar

    2013-09-01

    Neuromorphic engineering is a discipline devoted to the design and development of computational hardware that mimics the characteristics and capabilities of neuro-biological systems. In recent years, neuromorphic hardware systems have been implemented using a hybrid approach incorporating digital hardware so as to provide flexibility and scalability at the cost of power efficiency and some biological realism. This paper proposes an FPGA-based neuromorphic-like embedded system on a chip to generate locomotion patterns of periodic rhythmic movements inspired by Central Pattern Generators (CPGs). The proposed implementation follows a top-down approach where modularity and hierarchy are two desirable features. The locomotion controller is based on CPG models to produce rhythmic locomotion patterns or gaits for legged robots such as quadrupeds and hexapods. The architecture is configurable and scalable for robots with either different morphologies or different degrees of freedom (DOFs). Experiments performed on a real robot are presented and discussed. The obtained results demonstrate that the CPG-based controller provides the necessary flexibility to generate different rhythmic patterns at run-time suitable for adaptable locomotion. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Crawling at High Speeds: Steady Level Locomotion in the Spider Cupiennius salei-Global Kinematics and Implications for Centre of Mass Dynamics.

    Directory of Open Access Journals (Sweden)

    Tom Weihmann

    Full Text Available Spiders are an old yet very successful predatory group of arthropods. Their locomotor system differs from those of most other arthropods by the lack of extensor muscles in two major leg joints. Though specific functional characteristics can be expected regarding the locomotion dynamics of spiders, this aspect of movement physiology has been only scarcely examined so far. This study presents extensive analyses of a large dataset concerning global kinematics and the implications for dynamics of adult female specimens of the large Central American spider Cupiennius salei (Keyserling. The experiments covered the entire speed-range of straight runs at constant speeds. The analyses revealed specific characteristics of velocity dependent changes in the movements of the individual legs, as well as in the translational and rotational degrees of freedom of both the centre of mass and the body. In contrast to many other fast moving arthropods, C. salei avoid vertical fluctuations of their centre of mass during fast locomotion. Accordingly, aerial phases were not observed here. This behaviour is most likely a consequence of optimising energy expenditure with regard to the specific requirements of spiders' leg anatomy. A strong synchronisation of two alternating sets of legs appears to play only a minor role in the locomotion of large spiders. Reduced frequency and low centre of mass amplitudes as well as low angular changes of the body axes, in turn, seems to be the result of relatively low leg coordination.

  20. Kangaroo morphometrics: how Miocene kangaroos can inform us about palaeoenvironments and how giant Pleistocene kangaroos managed to locomote

    OpenAIRE

    Janis, Christine Marie

    2015-01-01

    Kangaroos are known today for their spectacular hopping locomotion, but kangaroo diversity in the past tells a different story. Some kinds of extinct kangaroos (sthenurines) grew so large that hopping would seem to be unlikely. Analysis of their bones shows that it is likely that they used walking on two legs as a means of getting around. The diversity of small kangaroos in the Miocene can inform us about palaeoenvironments, and how the higher levels of both temperature and atmospheric carbo...

  1. Locomotive track detection for underground

    Science.gov (United States)

    Ma, Zhonglei; Lang, Wenhui; Li, Xiaoming; Wei, Xing

    2017-08-01

    In order to improve the PC-based track detection system, this paper proposes a method to detect linear track for underground locomotive based on DSP + FPGA. Firstly, the analog signal outputted from the camera is sampled by A / D chip. Then the collected digital signal is preprocessed by FPGA. Secondly, the output signal of FPGA is transmitted to DSP via EMIF port. Subsequently, the adaptive threshold edge detection, polar angle and radius constrain based Hough transform are implemented by DSP. Lastly, the detected track information is transmitted to host computer through Ethernet interface. The experimental results show that the system can not only meet the requirements of real-time detection, but also has good robustness.

  2. Dynamic similarity in granular locomotion

    Science.gov (United States)

    Kamrin, Ken; Slonaker, James; Zhang, Qiong

    2017-11-01

    To model the flow of granular media with high accuracy, a number of subtleties arise and complex constitutive relations are needed to address them. However, making certain rheological simplifications produces a framework that is simple enough to obtain global rule-sets that can be used to aid in design without having to solve any partial differential equations or perform discrete element simulations. This talk will show how reduced-order rule-sets such as the Resistive Force Theory can be obtained from a basic frictional plasticity model, and how plasticity can further be used to produce a family of scaling laws in granular locomotion reminiscent of `wind tunnel' scaling laws in fluid dynamics. These are verified with experiments and numerical simulations.

  3. Mechanisms of Protrusion and Cell Locomotion

    Science.gov (United States)

    Keller, Hansuli

    Earlier models explaining cell locomotion are briefly reviewed. Then, a model explaining locomotion of non-adhesive Walker carcinosarcoma cells is proposed based on the following data: 1) Walker carcinosarcoma cells, which normally form lamellipodia, can produce forces for movement by at least two distinct actin-based mechanisms, 2) Lamellipodial motility is driven by local actin polymerization, but lamellipodia and actin-based mechanisms (polymerization or contraction) at the front are redundant for locomotion, 3) actomyosin-dependent contraction at the rear (body and/or uropod) is sufficient and necessary for locomotion, 4) fluid pressure can generate protrusion (blebs), 5) an intact cortical layer at the front tends to reduce the speed of locomotion, 6) there is no biologically significant difference in the efficiency of locomotion (speed, persistence, net displacement) of migrating cells showing either lamellipodia, blebs or no morphologically recognizable protrusions, 7) polymerized actin is concentrated in the cortical actin layer. Myosin IIA is preferentially associated with the actin cortex at the rear part of the cell. The data suggest that actomyosin-based contraction in the form of cortical contraction generates protrusion and locomotion in Walker carcinosarcoma cells as previously described in Amoebae. The role of actomyosin-dependent contraction and of fluid-driven mechanisms in other metazoan tissue cell lines is discussed.

  4. BiLBIQ A Biologically Inspired Robot with Walking and Rolling Locomotion

    CERN Document Server

    King, Ralf Simon

    2013-01-01

    The book ‘BiLBIQ: A biologically inspired Robot with walking and rolling locomotion’ deals with implementing a locomotion behavior observed in the biological archetype Cebrennus villosus to a robot prototype whose structural design needs to be developed.   The biological sample is investigated as far as possible and compared to other evolutional solutions within the framework of nature’s inventions. Current achievements in robotics are examined and evaluated for their relation and relevance to the robot prototype in question. An overview of what is state of the art in actuation ensures the choice of the hardware available and most suitable for this project. Through a constant consideration of the achievement of two fundamentally different ways of locomotion with one and the same structure, a robot design is developed and constructed taking hardware constraints into account. The development of a special leg structure that needs to resemble and replace body elements of the biological archetype is a speci...

  5. 49 CFR 230.21 - Steam locomotive number change.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive number change. 230.21 Section 230... Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is changed, the steam locomotive owner and/or operator must reflect the change in the upper right-hand corner of...

  6. Performance of raters to assess locomotion in dairy cattle

    NARCIS (Netherlands)

    Schlageter Tello, A.A.

    2015-01-01

    Abstract Locomotion scoring systems are procedures used to evaluate the quality of cows’ locomotion. When scoring locomotion, raters focus their attention on gait and posture traits that are described in the protocol. Using these traits, raters assign a locomotion score to

  7. 49 CFR 229.121 - Locomotive cab noise.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locomotive cab noise. 229.121 Section 229.121... § 229.121 Locomotive cab noise. (a) Performance standards for locomotives. (1) When tested for static noise in accordance with paragraph (a)(3) of this section, all locomotives of each design or model that...

  8. Leg cramps and restless legs syndrome during pregnancy.

    Science.gov (United States)

    Hensley, Jennifer G

    2009-01-01

    Sleep disturbance during pregnancy can result in excessive daytime sleepiness, diminished daytime performance, inability to concentrate, irritability, and the potential for an increased length of labor and increased risk of operative birth. Sleep disturbance may be the result of a sleep disorder, such as leg cramps, a common yet benign disorder, or restless legs syndrome, a sensorimotor disorder. Both disrupt sleep, are distressing to the pregnant woman, and mimic one another and other serious disorders. During pregnancy, up to 30% of women can be affected by leg cramps, and up to 26% can be affected by restless legs syndrome.

  9. Locomotive Assignment Problem with Heterogeneous Vehicle Fleet and Hiring External Locomotives

    Directory of Open Access Journals (Sweden)

    Dušan Teichmann

    2015-01-01

    Full Text Available This paper focuses on solving the problem of how to assign locomotives to assembled trains optimally. To solve the problem, linear programming is applied. The situation we model in the paper occurs in the conditions of a transport operator that provides rail transport in the Czech Republic. In the paper, an extended locomotive assignment problem is modeled; the transport operator can use different classes of the locomotives to serve individual connections, some connections must be served by a predefined locomotive class, and the locomotives can be allocated to several depots at the beginning. The proposed model also takes into consideration the fact that some connections can be served by the locomotives of external transport companies or operators. The presented model is applied to a real example in order to test its functionality.

  10. [Swollen leg with blisters].

    Science.gov (United States)

    Rafeiner, Ph; Templeton, A J; Vonesch, H J

    2005-10-05

    We report the case of a 84-year-old woman suffering from strong pain in her right leg initially resembling thrombosis of deep veins. Eight hours after admission a superficial blister developed at the calf with following hemorrhagic aspect and spontanous eruption of clear yellowish fluid. Later on a new blister appeared at the thigh. The patient died 33 hours after admission of streptococcal toxic shock syndrome. The latter was based on a necrotizing fasciitis. Streptoccus pyogenes (group A) could be cultivated from the blood and fluid of the blister. We discuss the clinical presentation of necrotizing fasciitis with "pain out of proportion" as characteristic complaint and the appropriate management.

  11. Textiloma in the leg

    Directory of Open Access Journals (Sweden)

    Patel Amol

    2007-01-01

    Full Text Available Textiloma is defined as a tumor formed due to retained gauze. It is rarely reported in the musculoskeletal system. We are presenting a case with a soft tissue swelling over the lateral aspect of the lower third of the leg, come for implant removal of the distal tibia and fibular fracture. We removed the soft tissue mass enbloc thinking it to be a benign tumor. On cutting the mass on the operation table, a gauze piece encased by fibrous tissue was found. Textiloma can present as tumoral forms and can mimic as a pseudo-tumor.

  12. Learning to balance on one leg: motor strategy and sensory weighting.

    NARCIS (Netherlands)

    van Dieen, J.H.; van Leeuwen, M.; Faber, G.S.

    2015-01-01

    We investigated motor and sensory changes underlying learning of a balance task. Fourteen participants practiced balancing on one leg on a board that could freely rotate in the frontal plane. They performed six, 16-s trials standing on one leg on a stable surface (2 trials without manipulation, 2

  13. Modeling limbless locomotion using ADAMS software

    Data.gov (United States)

    National Aeronautics and Space Administration — Until now, the methods used by probes or humans for locomotion on planetary surfaces have typically been restricted to variations of wheeled motion. As human...

  14. Locomotive to Automobile Baseline Crash Tests

    Science.gov (United States)

    1975-08-01

    Four Locomotive to Automobile Crash tests were performed by the Dynamic Science Division of Ultrasystems at DOT's High Speed Ground Test Center under contract to the Transportation Systems Center, which is conducting the work for the Federal Railroad...

  15. Issues in Locomotive Crew Management and Scheduling

    Science.gov (United States)

    1990-11-01

    This study explores matters related to the scheduling and management of locomotive crews, particularly as they : might contribute to fatigue and stress. It describes how crews are scheduled currently, why there is so much : unpredictability in schedu...

  16. BigDog-inspired studies in the locomotion of goats and dogs.

    Science.gov (United States)

    Lee, David V; Biewener, Andrew A

    2011-07-01

    Collision-based expenditure of mechanical energy and the compliance and geometry of the leg are fundamental, interrelated considerations in the mechanical design of legged runners. This article provides a basic context and rationale for experiments designed to inform each of these key areas in Boston Dynamic's BigDog robot. Although these principles have been investigated throughout the past few decades within different academic disciplines, BigDog required that they be considered together and in concert with an impressive set of control algorithms that are not discussed here. Although collision reduction is an important strategy for reducing mechanical cost of transport in the slowest and fastest quadrupedal gaits, walking and galloping, BigDog employed an intermediate-speed trotting gait without collision reduction. Trotting, instead, uses a spring-loaded inverted pendulum mechanism with potential for storage and return of elastic strain energy in appropriately compliant structures. Rather than tuning BigDog's built-in leg springs according to a spring-mass model-based virtual leg-spring constant , a much stiffer distal leg spring together with actuation of the adjacent joint provided good trotting dynamics and avoided functional limitations that might have been imposed by too much compliance in real-world terrain. Adjusting the directional compliance of the legs by adopting a knee-forward, elbow-back geometry led to more robust trotting dynamics by reducing perturbations about the pitch axis of the robot's center of mass (CoM). BigDog is the most successful large-scale, all-terrain trotting machine built to date and it continues to stimulate our understanding of legged locomotion in comparative biomechanics as well as in robotics.

  17. Stabilization of cat paw trajectory during locomotion.

    Science.gov (United States)

    Klishko, Alexander N; Farrell, Bradley J; Beloozerova, Irina N; Latash, Mark L; Prilutsky, Boris I

    2014-09-15

    We investigated which of cat limb kinematic variables during swing of regular walking and accurate stepping along a horizontal ladder are stabilized by coordinated changes of limb segment angles. Three hypotheses were tested: 1) animals stabilize the entire swing trajectory of specific kinematic variables (performance variables); and 2) the level of trajectory stabilization is similar between regular and ladder walking and 3) is higher for forelimbs compared with hindlimbs. We used the framework of the uncontrolled manifold (UCM) hypothesis to quantify the structure of variance of limb kinematics in the limb segment orientation space across steps. Two components of variance were quantified for each potential performance variable, one of which affected it ("bad variance," variance orthogonal to the UCM, VORT) while the other one did not ("good variance," variance within the UCM, VUCM). The analysis of five candidate performance variables revealed that cats during both locomotor behaviors stabilize 1) paw vertical position during the entire swing (VUCM > VORT, except in mid-hindpaw swing of ladder walking) and 2) horizontal paw position in initial and terminal swing (except for the entire forepaw swing of regular walking). We also found that the limb length was typically stabilized in midswing, whereas limb orientation was not (VUCM ≤ VORT) for both limbs and behaviors during entire swing. We conclude that stabilization of paw position in early and terminal swing enables accurate and stable locomotion, while stabilization of vertical paw position in midswing helps paw clearance. This study is the first to demonstrate the applicability of the UCM-based analysis to nonhuman movement. Copyright © 2014 the American Physiological Society.

  18. Stabilization of cat paw trajectory during locomotion

    Science.gov (United States)

    Klishko, Alexander N.; Farrell, Bradley J.; Beloozerova, Irina N.; Latash, Mark L.

    2014-01-01

    We investigated which of cat limb kinematic variables during swing of regular walking and accurate stepping along a horizontal ladder are stabilized by coordinated changes of limb segment angles. Three hypotheses were tested: 1) animals stabilize the entire swing trajectory of specific kinematic variables (performance variables); and 2) the level of trajectory stabilization is similar between regular and ladder walking and 3) is higher for forelimbs compared with hindlimbs. We used the framework of the uncontrolled manifold (UCM) hypothesis to quantify the structure of variance of limb kinematics in the limb segment orientation space across steps. Two components of variance were quantified for each potential performance variable, one of which affected it (“bad variance,” variance orthogonal to the UCM, VORT) while the other one did not (“good variance,” variance within the UCM, VUCM). The analysis of five candidate performance variables revealed that cats during both locomotor behaviors stabilize 1) paw vertical position during the entire swing (VUCM > VORT, except in mid-hindpaw swing of ladder walking) and 2) horizontal paw position in initial and terminal swing (except for the entire forepaw swing of regular walking). We also found that the limb length was typically stabilized in midswing, whereas limb orientation was not (VUCM ≤ VORT) for both limbs and behaviors during entire swing. We conclude that stabilization of paw position in early and terminal swing enables accurate and stable locomotion, while stabilization of vertical paw position in midswing helps paw clearance. This study is the first to demonstrate the applicability of the UCM-based analysis to nonhuman movement. PMID:24899676

  19. Characterization of undulatory locomotion in granular media

    Science.gov (United States)

    Peng, Zhiwei; Pak, On Shun; Elfring, Gwynn

    2015-11-01

    Undulatory locomotion is ubiquitous in nature, from the swimming of flagellated microorganisms in biological fluids, to the slithering of snakes on land, or the locomotion of sandfish lizards in sand. Analysis of locomotion in granular materials is relatively less developed compared with fluids partially due to a lack of validated force models but a recently proposed resistive force theory (RFT) in granular media has been shown useful in studying the locomotion of a sand-swimming lizard. Here we employ this model to investigate the swimming characteristics of an undulating slender filament of both finite and infinite length. For infinite swimmers, similar to results in viscous fluids, the sawtooth waveform is found to be optimal for propulsion speed at a given power consumption. We also compare the swimming characteristics of sinusoidal and sawtooth swimmers with swimming in viscous fluids. More complex swimming dynamics emerge when the assumption of an infinite swimmer is removed. In particular, we characterize the effects of drifting and pitching in terms of propulsion speed and efficiency for a finite sinusoidal swimmer. The results complement our understanding of undulatory locomotion and provide insights into the effective design of locomotive systems in granular media.

  20. Characteristics of undulatory locomotion in granular media

    Science.gov (United States)

    Peng, Zhiwei; Pak, On Shun; Elfring, Gwynn J.

    2016-03-01

    Undulatory locomotion is ubiquitous in nature and observed in different media, from the swimming of flagellated microorganisms in biological fluids, to the slithering of snakes on land, or the locomotion of sandfish lizards in sand. Despite the similarity in the undulating pattern, the swimming characteristics depend on the rheological properties of different media. Analysis of locomotion in granular materials is relatively less developed compared with fluids partially due to a lack of validated force models but recently a resistive force theory in granular media has been proposed and shown useful in studying the locomotion of a sand-swimming lizard. Here we employ the proposed model to investigate the swimming characteristics of a slender filament, of both finite and infinite length, undulating in a granular medium and compare the results with swimming in viscous fluids. In particular, we characterize the effects of drifting and pitching in terms of propulsion speed and efficiency for a finite sinusoidal swimmer. We also find that, similar to Lighthill's results using resistive force theory in viscous fluids, the sawtooth swimmer is the optimal waveform for propulsion speed at a given power consumption in granular media. The results complement our understanding of undulatory locomotion and provide insights into the effective design of locomotive systems in granular media.

  1. Push-Pull Locomotion for Vehicle Extrication

    Science.gov (United States)

    Creager, Colin M.; Johnson, Kyle A.; Plant, Mark; Moreland, Scott J.; Skonieczny, Krzysztof

    2014-01-01

    For applications in which unmanned vehicles must traverse unfamiliar terrain, there often exists the risk of vehicle entrapment. Typically, this risk can be reduced by using feedback from on-board sensors that assess the terrain. This work addressed the situations where a vehicle has already become immobilized or the desired route cannot be traversed using conventional rolling. Specifically, the focus was on using push-pull locomotion in high sinkage granular material. Push-pull locomotion is an alternative mode of travel that generates thrust through articulated motion, using vehicle components as anchors to push or pull against. It has been revealed through previous research that push-pull locomotion has the capacity for generating higher net traction forces than rolling, and a unique optical flow technique indicated that this is the result of a more efficient soil shearing method. It has now been found that pushpull locomotion results in less sinkage, lower travel reduction, and better power efficiency in high sinkage material as compared to rolling. Even when starting from an "entrapped" condition, push-pull locomotion was able to extricate the test vehicle. It is the authors' recommendation that push-pull locomotion be considered as a reliable back-up mode of travel for applications where terrain entrapment is a possibility.

  2. Biomechanics of gecko locomotion: the patterns of reaction forces on inverted, vertical and horizontal substrates

    International Nuclear Information System (INIS)

    Wang, Zhouyi; Dai, Zhendong; Ji, Aihong; Xing, Qiang; Ren, Lei; Dai, Liming

    2015-01-01

    The excellent locomotion ability of geckos on various rough and/or inclined substrates has attracted scientists’ attention for centuries. However, the moving ability of gecko-mimicking robots on various inclined surfaces still lags far behind that of geckos, mainly because our understanding of how geckos govern their locomotion is still very poor. To reveal the fundamental mechanism of gecko locomotion and also to facilitate the design of gecko-mimicking robots, we have measured the reaction forces (RFs) acting on each individual foot of moving geckos on inverted, vertical and horizontal substrates (i.e. ceiling, wall and floor), have associated the RFs with locomotion behaviors by using high-speed camera, and have presented the relationships of the force components with patterns of reaction forces (PRFs). Geckos generate different PRF on ceiling, wall and floor, that is, the PRF is determined by the angles between the direction of gravity and the substrate on which geckos move. On the ceiling, geckos produce reversed shear forces acting on the front and hind feet, which pull away from the body in both lateral and fore-aft directions. They use a very large supporting angle from 21° to 24° to reduce the forces acting on their legs and feet. On the floor, geckos lift their bodies using a supporting angle from 76° to 78°, which not only decreases the RFs but also improves their locomotion ability. On the wall, geckos generate a reliable self-locking attachment by using a supporting angle of 14.8°, which is only about half of the critical angle of detachment. (paper)

  3. From Beetles in Nature to the Laboratory: Actuating Underwater Locomotion on Hydrophobic Surfaces.

    Science.gov (United States)

    Pinchasik, Bat-El; Steinkühler, Jan; Wuytens, Pieter; Skirtach, Andre G; Fratzl, Peter; Möhwald, Helmuth

    2015-12-29

    The controlled wetting and dewetting of surfaces is a primary mechanism used by beetles in nature, such as the ladybird and the leaf beetle for underwater locomotion.1 Their adhesion to surfaces underwater is enabled through the attachment of bubbles trapped in their setae-covered legs. Locomotion, however, is performed by applying mechanical forces in order to move, attach, and detach the bubbles in a controlled manner. Under synthetic conditions, however, when a bubble is bound to a surface, it is nearly impossible to maneuver without the use of external stimuli. Thus, actuated wetting and dewetting of surfaces remain challenges. Here, electrowetting-on-dielectric (EWOD) is used for the manipulation of bubble-particle complexes on unpatterned surfaces. Bubbles nucleate on catalytic Janus disks adjacent to a hydrophobic surface. By changing the wettability of the surface through electrowetting, the bubbles show a variety of reactions, depending on the shape and periodicity of the electrical signal. Time-resolved (μs) imaging of bubble radial oscillations reveals possible mechanisms for the lateral mobility of bubbles on a surface under electrowetting: bubble instability is induced when electric pulses are carefully adjusted. This instability is used to control the surface-bound bubble locomotion and is described in terms of the change in surface energy. It is shown that a deterministic force applied normal can lead to a random walk of micrometer-sized bubbles by exploiting the phenomenon of contact angle hysteresis. Finally, bubble use in nature for underwater locomotion and the actuated bubble locomotion presented in this study are compared.

  4. Biomechanics of gecko locomotion: the patterns of reaction forces on inverted, vertical and horizontal substrates.

    Science.gov (United States)

    Wang, Zhouyi; Dai, Zhendong; Ji, Aihong; Ren, Lei; Xing, Qiang; Dai, Liming

    2015-02-04

    The excellent locomotion ability of geckos on various rough and/or inclined substrates has attracted scientists' attention for centuries. However, the moving ability of gecko-mimicking robots on various inclined surfaces still lags far behind that of geckos, mainly because our understanding of how geckos govern their locomotion is still very poor. To reveal the fundamental mechanism of gecko locomotion and also to facilitate the design of gecko-mimicking robots, we have measured the reaction forces (RFs) acting on each individual foot of moving geckos on inverted, vertical and horizontal substrates (i.e. ceiling, wall and floor), have associated the RFs with locomotion behaviors by using high-speed camera, and have presented the relationships of the force components with patterns of reaction forces (PRFs). Geckos generate different PRF on ceiling, wall and floor, that is, the PRF is determined by the angles between the direction of gravity and the substrate on which geckos move. On the ceiling, geckos produce reversed shear forces acting on the front and hind feet, which pull away from the body in both lateral and fore-aft directions. They use a very large supporting angle from 21° to 24° to reduce the forces acting on their legs and feet. On the floor, geckos lift their bodies using a supporting angle from 76° to 78°, which not only decreases the RFs but also improves their locomotion ability. On the wall, geckos generate a reliable self-locking attachment by using a supporting angle of 14.8°, which is only about half of the critical angle of detachment.

  5. PSO-SVM-Based Online Locomotion Mode Identification for Rehabilitation Robotic Exoskeletons.

    Science.gov (United States)

    Long, Yi; Du, Zhi-Jiang; Wang, Wei-Dong; Zhao, Guang-Yu; Xu, Guo-Qiang; He, Long; Mao, Xi-Wang; Dong, Wei

    2016-09-02

    Locomotion mode identification is essential for the control of a robotic rehabilitation exoskeletons. This paper proposes an online support vector machine (SVM) optimized by particle swarm optimization (PSO) to identify different locomotion modes to realize a smooth and automatic locomotion transition. A PSO algorithm is used to obtain the optimal parameters of SVM for a better overall performance. Signals measured by the foot pressure sensors integrated in the insoles of wearable shoes and the MEMS-based attitude and heading reference systems (AHRS) attached on the shoes and shanks of leg segments are fused together as the input information of SVM. Based on the chosen window whose size is 200 ms (with sampling frequency of 40 Hz), a three-layer wavelet packet analysis (WPA) is used for feature extraction, after which, the kernel principal component analysis (kPCA) is utilized to reduce the dimension of the feature set to reduce computation cost of the SVM. Since the signals are from two types of different sensors, the normalization is conducted to scale the input into the interval of [0, 1]. Five-fold cross validation is adapted to train the classifier, which prevents the classifier over-fitting. Based on the SVM model obtained offline in MATLAB, an online SVM algorithm is constructed for locomotion mode identification. Experiments are performed for different locomotion modes and experimental results show the effectiveness of the proposed algorithm with an accuracy of 96.00% ± 2.45%. To improve its accuracy, majority vote algorithm (MVA) is used for post-processing, with which the identification accuracy is better than 98.35% ± 1.65%. The proposed algorithm can be extended and employed in the field of robotic rehabilitation and assistance.

  6. Differentiating nocturnal leg cramps and restless legs syndrome.

    Science.gov (United States)

    Rana, Abdul Qayyum; Khan, Fatima; Mosabbir, Abdullah; Ondo, William

    2014-07-01

    Leg pain and discomfort are common complaints in any primary physician's clinic. Two common causes of pain or discomfort in legs are nocturnal leg cramps (NLC) and restless leg syndrome (RLS). NLC present as painful and sudden contractions mostly in part of the calf. Diagnosis of NLC is mainly clinical and sometimes involves investigations to rule out other mimics. RLS is a condition characterized by the discomfort or urge to move the lower limbs, which occurs at rest or in the evening/night. The similarity of RLS and leg cramps poses the issue of errors in diagnosing and differentiating the two. In this paper we review the pathopysiology of each entity and their diagnosis as well as treatment. The two conditions are then compared to appreciate the differences and similarities. Finally, suggestions are recommended for complete assessment.

  7. The dynamics of quadrupedal locomotion.

    Science.gov (United States)

    Pandy, M G; Kumar, V; Berme, N; Waldron, K J

    1988-08-01

    This paper presents a dynamical analysis of quadrupedal locomotion, with specific reference to an adult Nubian goat. Measurements of ground reaction forces and limb motion are used to assess variations in intersegmental forces, joint moments, and instantaneous power for three discernible gaits: walking, running, and jumping. In each case, inertial effects of the torso are shown to dominate to the extent that lower-extremity contributions may be considered negligible. Footforces generated by the forelimbs exceed those exerted by the hindlimbs; and, in general, ground reactions increase with speed. The shoulder and hip dominate mechanical energy production during walking, while the knee plays a more significant role in running. In both cases, however, the elbow absorbs energy, and by so doing functions primarily as a damping (control) element. As opposed to either walking or running, jumping requires total horizontal retardation of the body's center of mass. In this instance, generating the necessary vertical thrust amounts to energy absorption at all joints of the lower extremities.

  8. The PS locomotive runs again

    CERN Document Server

    2001-01-01

    Over forty years ago, the PS train entered service to steer the magnets of the accelerator into place... ... a service that was resumed last Tuesday. Left to right: Raymond Brown (CERN), Claude Tholomier (D.B.S.), Marcel Genolin (CERN), Gérard Saumade (D.B.S.), Ingo Ruehl (CERN), Olivier Carlier (D.B.S.), Patrick Poisot (D.B.S.), Christian Recour (D.B.S.). It is more than ten years since people at CERN heard the rumbling of the old PS train's steel wheels. Last Tuesday, the locomotive came back into service to be tested. It is nothing like the monstrous steel engines still running on conventional railways -just a small electric battery-driven vehicle employed on installing the magnets for the PS accelerator more than 40 years ago. To do so, it used the tracks that run round the accelerator. In fact, it is the grandfather of the LEP monorail. After PS was commissioned in 1959, the little train was used more and more rarely. This is because magnets never break down, or hardly ever! In fact, the loc...

  9. Klinefelter Syndrome With Leg Ulcers

    Directory of Open Access Journals (Sweden)

    Narendra G

    1999-01-01

    Full Text Available Leg ulcers are frequently caused by venous insufficiency, arterial insufficiency, neuropathy, or a combination of these factors. Klinefelter syndrome in association with chronic leg ulcers have been reported earlier. We report a case of Klinefelter syndrome with non- healing ulcer. The diagnosis of the Klinefelter syndrome was confirmed by karyotyping.

  10. Biologically Inspired Modular Neural Control for a Leg-Wheel Hybrid Robot

    DEFF Research Database (Denmark)

    Manoonpong, Poramate; Wörgötter, Florentin; Laksanacharoen, Pudit

    2014-01-01

    In this article we present modular neural control for a leg-wheel hybrid robot consisting of three legs with omnidirectional wheels. This neural control has four main modules having their functional origin in biological neural systems. A minimal recurrent control (MRC) module is for sensory signal...... processing and state memorization. Its outputs drive two front wheels while the rear wheel is controlled through a velocity regulating network (VRN) module. In parallel, a neural oscillator network module serves as a central pattern generator (CPG) controls leg movements for sidestepping. Stepping directions...... are achieved by a phase switching network (PSN) module. The combination of these modules generates various locomotion patterns and a reactive obstacle avoidance behavior. The behavior is driven by sensor inputs, to which additional neural preprocessing networks are applied. The complete neural circuitry...

  11. Relationship between osteology and aquatic locomotion in birds: determining modes of locomotion in extinct Ornithurae.

    Science.gov (United States)

    Hinić-Frlog, S; Motani, R

    2010-02-01

    The evolutionary history of aquatic invasion in birds would be incomplete without incorporation of extinct species. We show that aquatic affinities in fossil birds can be inferred by multivariate analysis of skeletal features and locomotion of 245 species of extant birds. Regularized discriminant analyses revealed that measurements of appendicular skeletons successfully separated diving birds from surface swimmers and flyers, while also discriminating among different underwater modes of swimming. The high accuracy of this method allows detection of skeletal characteristics that are indicative of aquatic locomotion and inference of such locomotion in bird species with insufficient behavioural information. Statistical predictions based on the analyses confirm qualitative assessments for both foot-propelled (Hesperornithiformes) and wing-propelled (Copepteryx) underwater locomotion in fossil birds. This is the first quantitative inference of underwater modes of swimming in fossil birds, enabling future studies of locomotion in extinct birds and evolutionary transitions among locomotor modes in avian lineage.

  12. Development of locomotion in a subsocial spider.

    Science.gov (United States)

    Ahn, Soon Kil; Kim, Kil Won

    2015-04-01

    Following consumption of their mother, the subsocial spider Amaurobius ferox remain together, exhibiting distinctive behaviours in response to intruders into the natal nest. We examined the ontogeny and characteristics of locomotory behaviours in A. ferox during this post-maternal social period. Locomotion of the spiderlings, elicited by the introduction of a cricket larva into the natal web, fell into two categories: 'abrupt locomotion' (AL) and 'ordinary locomotion' (OL). AL involved rapid and linear movement, whereas OL involved slower motion, not necessarily in a straight line. Both types of locomotion varied with spiderling age. AL appeared for only a limited period of time whereas the frequency of OL increased linearly over time. AL occurred more collectively than OL: the percentage of participants in a bout of locomotion was 18.67±17.71% vs. 10.22±9.33%. The collective tendency of AL increased up until the seventh day and then decreased, whereas that of OL progressively decreased. The direction of AL responses to the intruder did not vary over time; however, for OL, movements towards increased in frequency over time. Locomotory responses also varied with the intensity of intruder movement. Including transient behaviours, the chronology of different behaviours suggests that behavioural development in A. ferox involves maternal influences and weakens group cohesion and collective tendency. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Stable isotopes

    International Nuclear Information System (INIS)

    Evans, D.K.

    1986-01-01

    Seventy-five percent of the world's stable isotope supply comes from one producer, Oak Ridge Nuclear Laboratory (ORNL) in the US. Canadian concern is that foreign needs will be met only after domestic needs, thus creating a shortage of stable isotopes in Canada. This article describes the present situation in Canada (availability and cost) of stable isotopes, the isotope enrichment techniques, and related research programs at Chalk River Nuclear Laboratories (CRNL)

  14. Restless legs syndrome

    Directory of Open Access Journals (Sweden)

    Ovallath S

    2012-10-01

    Full Text Available Sujith Ovallath, P DeepaJames Parkinson's Movement Disorder Research Centre, Kannur Medical College, Kerala, IndiaBackground: Restless legs syndrome (RLS is a common sleep-related disorder characterized by abnormal sensation and an urge to move the lower limbs. Symptoms occur at rest in the evening or at night, and they are alleviated by moving the affected extremity or by walking. Although the exact etiopathogenesis of RLS remains elusive, the rapid improvement of symptoms with dopaminergic agents suggests that dopaminergic system dysfunction may be a basic mechanism. Dopaminergic agents are the best-studied agents, and are considered first-line treatment of RLS.Objective: To review the diagnostic criteria, clinical features, etiopathogenesis, and the treatment options of RLS.Methods: The suggestions are based on evidence from studies published in peer-reviewed journals, or upon a comprehensive review of the medical literature.Results/conclusion: Extensive data are available for proving the link between the dopaminergic system and RLS. A possible genetic link also has been studied extensively. Dopamine agonists, especially pramipexole and ropinirole, are particularly useful in the treatment of RLS. Pharmacological treatment should however be limited to those patients who suffer from clinically relevant RLS with impaired sleep quality or quality of life.Keywords: dopamine, levodopa, pramipexole

  15. Interlimb Coordination in Body-Weight Supported Locomotion: A Pilot Study

    Science.gov (United States)

    Seiterle, Stefan; Susko, Tyler; Artemiadis, Panagiotis K.; Riener, Robert; Krebs, Hermano Igo

    2015-01-01

    Locomotion involves complex neural networks responsible for automatic and volitional actions. During locomotion, motor strategies can rapidly compensate for any obstruction or perturbation that could interfere with forward progression. In this pilot study, we examined the contribution of interlimb pathways for evoking muscle activation patterns in the contralateral limb when a unilateral perturbation was applied and in the case where body weight was externally supported. In particular, the latency of neuromuscular responses was measured, while the stimulus to afferent feedback was limited. The pilot experiment was conducted with six healthy young subjects. It employed the MIT-Skywalker (beta-prototype), a novel device intended for gait therapy. Subjects were asked to walk on the split-belt treadmill, while a fast unilateral perturbation was applied mid-stance by unexpectedly lowering one side of the split-treadmill walking surfaces. Subject's weight was externally supported via the body-weight support system consisting of an underneath bicycle seat and the torso was stabilized via a loosely fitted chest harness. Both the weight support and the chest harness limited the afferent feedback. The unilateral perturbations evoked changes in the electromyographic activity of the non-perturbed contralateral leg. The latency of all muscle responses exceeded 100 ms, which precludes the conjecture that spinal cord alone is responsible for the perturbation response. It suggests the role of supraspinal or midbrain level pathways at the inter-leg coordination during gait. PMID:25990210

  16. Age-related modifications of muscle synergies and spinal cord activity during locomotion.

    Science.gov (United States)

    Monaco, Vito; Ghionzoli, Alessio; Micera, Silvestro

    2010-10-01

    Recent findings have shown that neural circuits located in the spinal cord drive muscular activations during locomotion while intermediating between descending signals and peripheral sensory information. This relationship could be modified by the natural aging process. To address this issue, the activity of 12 ipsilateral leg muscles was analyzed in young and elderly people (7 subjects per group) while walking at six different cadences (40-140 steps/min). These signals were used to extract synergies underlying muscle activation and to map the motoneuronal activity of the pools belonging to the lumbosacral enlargement (L(2)-S(2)). The comparison between the two groups showed that neither temporal patterning of motor primitives nor muscles loading synergies seemed to be significantly affected by aging. Conversely, as the cadence increased, spinal maps differ significantly between the groups, showing higher and scattered activity during the whole gait cycle in elders and well-defined bursts in young subjects. The results suggested that motor primitives lead the synchronization of muscle activation mainly depending on the biomechanical demand of the locomotion; hence they are not significantly affected by aging. Nevertheless, at the spinal cord level, biomechanical requirements, peripheral afference, and descending inputs are differently integrated between the two groups, probably reflecting age-related changes of both nervous system and motor control strategies during locomotion.

  17. Restless legs syndrome: literature review

    Directory of Open Access Journals (Sweden)

    Emmanouil Symvoulakis

    Full Text Available Restless legs syndrome is a distressing condition, with negative effects on sleep and daytime activities that affect personal, family and occupational life. The overall impact of restless legs syndrome on quality of life is comparable to that of chronic and frustrating conditions such as depression and diabetes. Misdiagnosis and inappropriate treatment may increase patients' suffering in terms of uncertainty, overuse or misuse of care services and lack of trust. Presenting a synthesis of the main topics in the literature on restless legs syndrome facilitates for a better understanding and its management in primary care settings.

  18. Measurement of body fat using leg to leg bioimpedance

    OpenAIRE

    Sung, R; Lau, P; Yu, C; Lam, P; Nelson, E

    2001-01-01

    AIMS—(1) To validate a leg to leg bioimpedance analysis (BIA) device in the measurement of body composition in children by assessment of its agreement with dual energy x ray absorptiometry (DXA) and its repeatability. (2) To establish a reference range of percentage body fat in Hong Kong Chinese children.
METHODS—Sequential BIA and DXA methods were used to determine body composition in 49 children aged 7-18 years; agreement between the two methods was calculated. Repea...

  19. Passive appendages aid locomotion through symmetry breaking

    Science.gov (United States)

    Bagheri, Shervin; Lacis, Ugis; Mazzino, Andrea; Kellay, Hamid; Brosse, Nicolas; Lundell, Fredrik; Ingremeau, Francois

    2014-11-01

    Plants and animals use plumes, barbs, tails, feathers, hairs, fins, and other types of appendages to aid locomotion. Despite their enormous variation, passive appendages may contribute to locomotion by exploiting the same physical mechanism. We present a new mechanism that applies to body appendages surrounded by a separated flow, which often develops behind moving bodies larger than a few millimeters. We use theory, experiments, and numerical simulations to show that bodies with protrusions turn and drift by exploiting a symmetry-breaking instability similar to the instability of an inverted pendulum. Our model explains why the straight position of an appendage in flowing fluid is unstable and how it stabilizes either to the left or right of the incoming fluid flow direction. The discovery suggests a new mechanism of locomotion that may be relevant for certain organisms; for example, how plumed seeds may drift without wind and how motile animals may passively reorient themselves.

  20. Numerical simulation of human biped locomotion

    International Nuclear Information System (INIS)

    Ishiguro, Misako; Fujisaki, Masahide

    1988-04-01

    This report describes the numerical simulation of the motion of human-like robot which is one of the research theme of human acts simulation program (HASP) begun at the Computing Center of JAERI in 1987. The purpose of the theme is to model the human motion using robotics kinematic/kinetic equations and to get the joint angles as the solution. As the first trial, we treat the biped locomotion (walking) which is the most fundamental human motion. We implemented a computer program on FACOM M-780 computer, where the program is originated from the book of M. Vukobratovic in Yugoslavia, and made a graphic program to draw a walking shot sequence. Mainly described here are the mathematical model of the biped locomotion, implementation method of the computer program, input data for basic walking pattern, computed results and its validation, and graphic representation of human walking image. Literature survey on robotics equation and biped locomotion is also included. (author)

  1. A model for nematode locomotion in soil

    Science.gov (United States)

    Hunt, H. William; Wall, Diana H.; DeCrappeo, Nicole; Brenner, John S.

    2001-01-01

    Locomotion of nematodes in soil is important for both practical and theoretical reasons. We constructed a model for rate of locomotion. The first model component is a simple simulation of nematode movement among finite cells by both random and directed behaviours. Optimisation procedures were used to fit the simulation output to data from published experiments on movement along columns of soil or washed sand, and thus to estimate the values of the model's movement coefficients. The coefficients then provided an objective means to compare rates of locomotion among studies done under different experimental conditions. The second component of the model is an equation to predict the movement coefficients as a function of controlling factors that have been addressed experimentally: soil texture, bulk density, water potential, temperature, trophic group of nematode, presence of an attractant or physical gradient and the duration of the experiment. Parameters of the equation were estimated by optimisation to achieve a good fit to the estimated movement coefficients. Bulk density, which has been reported in a minority of published studies, is predicted to have an important effect on rate of locomotion, at least in fine-textured soils. Soil sieving, which appears to be a universal practice in laboratory studies of nematode movement, is predicted to negatively affect locomotion. Slower movement in finer textured soils would be expected to increase isolation among local populations, and thus to promote species richness. Future additions to the model that might improve its utility include representing heterogeneity within populations in rate of movement, development of gradients of chemical attractants, trade-offs between random and directed components of movement, species differences in optimal temperature and water potential, and interactions among factors controlling locomotion.

  2. Analysis of fuel cell hybrid locomotives

    Science.gov (United States)

    Miller, Arnold R.; Peters, John; Smith, Brian E.; Velev, Omourtag A.

    Led by Vehicle Projects LLC, an international industry-government consortium is developing a 109 t, 1.2 MW road-switcher locomotive for commercial and military railway applications. As part of the feasibility and conceptual-design analysis, a study has been made of the potential benefits of a hybrid power plant in which fuel cells comprise the prime mover and a battery or flywheel provides auxiliary power. The potential benefits of a hybrid power plant are: (i) enhancement of transient power and hence tractive effort; (ii) regenerative braking; (iii) reduction of capital cost. Generally, the tractive effort of a locomotive at low speed is limited by wheel adhesion and not by available power. Enhanced transient power is therefore unlikely to benefit a switcher locomotive, but could assist applications that require high acceleration, e.g. subway trains with all axles powered. In most cases, the value of regeneration in locomotives is minimal. For low-speed applications such as switchers, the available kinetic energy and the effectiveness of traction motors as generators are both minimal. For high-speed heavy applications such as freight, the ability of the auxiliary power device to absorb a significant portion of the available kinetic energy is low. Moreover, the hybrid power plant suffers a double efficiency penalty, namely, losses occur in both absorbing and then releasing energy from the auxiliary device, which result in a net storage efficiency of no more than 50% for present battery technology. Capital cost in some applications may be reduced. Based on an observed locomotive duty cycle, a cost model shows that a hybrid power plant for a switcher may indeed reduce capital cost. Offsetting this potential benefit are the increased complexity, weight and volume of the power plant, as well as 20-40% increased fuel consumption that results from lower efficiency. Based on this analysis, the consortium has decided to develop a pure fuel cell road-switcher locomotive

  3. Large and limbless: the locomotion of snakes

    Science.gov (United States)

    Hu, David

    2008-03-01

    In efforts to understand snake locomotion, we consider one of their various gaits. By contracting and extending their bodies unidirectionally like a slinky, large snakes propel themselves in a straight line. In a combined experimental and theoretical investigation, we here report on the dynamics of a boa constrictor alongside the analysis of an n-linked extensible crawler model. Constraints on their locomotion are quantified and discussed, such as the elasticity, frictional anisotropy and abrasive wear of their skin. Also presented are certain snake behaviors that culminate in their tying themselves into knots.

  4. Locomotion of Paramecium in patterned environments

    Science.gov (United States)

    Park, Eun-Jik; Eddins, Aja; Kim, Junil; Yang, Sung; Jana, Saikat; Jung, Sunghwan

    2011-10-01

    Ciliary organisms like Paramecium Multimicronucleatum locomote by synchronized beating of cilia that produce metachronal waves over their body. In their natural environments they navigate through a variety of environments especially surfaces with different topology. We study the effects of wavy surfaces patterned on the PDMS channels on the locomotive abilities of Paramecium by characterizing different quantities like velocity amplitude and wavelength of the trajectories traced. We compare this result with the swimming characteristics in straight channels and draw conclusions about the effects of various patterned surfaces.

  5. DESIGN IMPROVEMENT OF THE LOCOMOTIVE RUNNING GEARS

    Directory of Open Access Journals (Sweden)

    S. V. Myamlin

    2013-09-01

    Full Text Available Purpose. To determine the dynamic qualities of the mainline freight locomotives characterizing the safe motion in tangent and curved track sections at all operational speeds, one needs a whole set of studies, which includes a selection of the design scheme, development of the corresponding mathematical model of the locomotive spatial fluctuations, construction of the computer calculation program, conducting of the theoretical and then experimental studies of the new designs. In this case, one should compare the results with existing designs. One of the necessary conditions for the qualitative improvement of the traction rolling stock is to define the parameters of its running gears. Among the issues related to this problem, an important place is occupied by the task of determining the locomotive dynamic properties on the stage of projection, taking into account the selected technical solutions in the running gear design. Methodology. The mathematical modeling studies are carried out by the numerical integration method of the dynamic loading for the mainline locomotive using the software package «Dynamics of Rail Vehicles » («DYNRAIL». Findings. As a result of research for the improvement of locomotive running gear design it can be seen that the creation of the modern locomotive requires from engineers and scientists the realization of scientific and technical solutions. The solutions enhancing design speed with simultaneous improvement of the traction, braking and dynamic qualities to provide a simple and reliable design, especially the running gear, reducing the costs for maintenance and repair, low initial cost and operating costs for the whole service life, high traction force when starting, which is as close as possible to the ultimate force of adhesion, the ability to work in multiple traction mode and sufficient design speed. Practical Value. The generalization of theoretical, scientific and methodological, experimental studies aimed

  6. Liquid cooled viscoelastic actuation for robust legged robot locomotion, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The work proposed here seeks to significantly improve actuation technology for mission-capable articulated robots and exoskeletons such as NASA's Robonaut 2,...

  7. The Perceived Naturalness of Virtual Locomotion Methods Devoid of Explicit Leg Movements

    DEFF Research Database (Denmark)

    Nilsson, Niels Christian; Serafin, Stefania; Nordahl, Rolf

    2013-01-01

    Walking-In-Place (WIP) techniques have potential in terms of solving the problem arising when an immersive virtual environment offers a larger freedom of movement than the physical environment. Such techniques are particularly useful when the spatial constraints are very prominent, as they are li...

  8. Locomotive Schedule Optimization for Da-qin Heavy Haul Railway

    OpenAIRE

    Su, Ruiye; Zhou, Leishan; Tang, Jinjin

    2015-01-01

    The main difference between locomotive schedule of heavy haul railways and that of regular rail transportation is the number of locomotives utilized for one train. One heavy-loaded train usually has more than one locomotive, but a regular train only has one. This paper develops an optimization model for the multilocomotive scheduling problem (MLSP) through analyzing the current locomotive schedule of Da-qin Railway. The objective function of our paper is to minimize the total number of utiliz...

  9. Leg pain and gynecologic malignancy.

    Science.gov (United States)

    Singh, Lilly; Stevens, Erin E

    2013-09-01

    Gynecologic malignancies affect more than 83 000 women in the United States, each year. Because the disease involves the pelvis, many patients have side effects distal to this area in their lower extremities. The differential diagnosis of leg pain can be divided into vascular, neurologic, and musculoskeletal causes. In this review article, we address numerous etiologies of leg pain, reviewing the prevalence of disease, physical examination findings, diagnostic as well as treatment modalities.

  10. Towards Biomimetic Virtual Constraint Control of a Powered Prosthetic Leg.

    Science.gov (United States)

    Gregg, Robert D; Sensinger, Jonathon W

    2014-01-01

    This brief presents a novel control strategy for a powered prosthetic ankle based on a biomimetic virtual constraint. We first derive a kinematic constraint for the "effective shape" of the human ankle-foot complex during locomotion. This shape characterizes ankle motion as a function of the Center of Pressure (COP)-the point on the foot sole where the resultant ground reaction force is imparted. Since the COP moves monotonically from heel to toe during steady walking, we adopt the COP as a mechanical representation of the gait cycle phase in an autonomous feedback controller. We show that our kinematic constraint can be enforced as a virtual constraint by an output linearizing controller that uses only feedback available to sensors onboard a prosthetic leg. Using simulations of a passive walking model with feet, we show that this novel controller exactly enforces the desired effective shape whereas a standard impedance (i.e., proportional-derivative) controller cannot. This work provides a single, biomimetic control law for the entire single-support period during robot-assisted locomotion.

  11. The Role of Adaptation in Body Load-Regulating Mechanisms During Locomotion

    Science.gov (United States)

    Ruttley, Tara; Holt, Christopher; Mulavara, Ajitkumar; Bloomberg, Jacob

    2010-01-01

    the body load-regulating mechanisms that included increased head movement amplitude, increased knee and ankle flexion, and increased stance, stride, and double support time, with no change in the performance of the task with respect to that measured before exposure to BWS. These changes in locomotor control are opposite to that reported during 40% BWS exposure and indicative of an after-effect after removal of the adaptive stimulus. Therefore, it is evident that just 30 minutes of 40% BWS during locomotion was sufficient to induce adaptive modifications in the body load sensing systems that contribute to reorganization of sensory contributions to stable locomotor control.

  12. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not more...

  13. A survey report for the biped locomotion robot compensating three-axis moment

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Ichiro; Takanishi, Atsuo [Waseda Univ., Tokyo (Japan); Kume, Etsuo

    1994-10-01

    A dynamic walking simulation of biped locomotion robots based on the Zero Moment Point (ZMP) criterion is being conducted at JAERI. The ZMP criterion to obtain the stable walking patterns is that respective sums of moments around pitch-axis and roll-axis which act on the robot are equal to zero. So far, as for the rest moment around yaw-axis, the moment is balanced to frictional force, assuming that the frictional force between robot`s sole and floor is sufficiently large in our study. According to a recent paper, however, slipping around yaw-axis between robot`s sole and floor has occurred as the walking speed becomes faster, and the slipping has made the walking unstable. So influence of this moment can not be ignored for the fast walking. A survey has been performed for collecting relevant information from already existing biped locomotion robots. This is a survey report for the biped locomotion robot compensating three-axis moment by a trunk motion: the WL-12RV designed and developed at Waseda University. The WL-12RV has been realized 1.5 times as fast as dynamic walking compared with a biped locomotion robot compensating two-axis moment (e.g. WL-12RIV). This report includes the machine model, control method and results of walking experiments of the WL-12RV. (author).

  14. Relation between observed locomotion traits and locomotion score in dairy cows.

    Science.gov (United States)

    Schlageter-Tello, Andrés; Bokkers, Eddie A M; Groot Koerkamp, Peter W G; Van Hertem, Tom; Viazzi, Stefano; Romanini, Carlos E B; Halachmi, Ilan; Bahr, Claudia; Berckmans, Daniël; Lokhorst, Kees

    2015-12-01

    Lameness is still an important problem in modern dairy farming. Human observation of locomotion, by looking at different traits in one go, is used in practice to assess locomotion. The objectives of this article were to determine which individual locomotion traits are most related to locomotion scores in dairy cows, and whether experienced raters are capable of scoring these individual traits consistently. Locomotion and 5 individual locomotion traits (arched back, asymmetric gait, head bobbing, reluctance to bear weight, and tracking up) were scored independently on a 5-level scale for 58 videos of different cows. Videos were shown to 10 experienced raters in 2 different scoring sessions. Relations between locomotion score and traits were estimated by 3 logistic regression models aiming to calculate the size of the fixed effects on the probability of scoring a cow in 1 of the 5 levels of the scale (model 1) and the probability of classifying a cow as lame (locomotion score ≥3; model 2) or as severely lame (locomotion score ≥4; model 3). Fixed effects were rater, session, traits, and interactions among fixed effects. Odds ratios were calculated to estimate the relative probability to classify a cow as lame when an altered (trait score ≥3) or severely altered trait (trait score ≥4) was present. Overall intrarater and interrater reliability and agreement were calculated as weighted kappa coefficient (κw) and percentage of agreement, respectively. Specific intrarater and interrater agreement for individual levels within a 5-level scale were calculated. All traits were significantly related to the locomotion score when scored with a 5-level scale and when classified as (severely) lame or nonlame. Odds ratios for altered and severely altered traits were 10.8 and 14.5 for reluctance to bear weight, 6.5 and 7.2 for asymmetric gait, and 4.8 and 3.2 for arched back, respectively. Raters showed substantial variation in reliability and agreement values when scoring

  15. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of a...

  16. 76 FR 2199 - Locomotive Safety Standards

    Science.gov (United States)

    2011-01-12

    ... existing regulations. The proposal incorporates existing industry and engineering best practices related to... Overview of Proposed Requirements Trends in locomotive operation, concern about the safe design of... used many of the same sub-assemblies of pneumatic valves, electronic controls and software (referred to...

  17. Locomotion of C elegans in structured environments

    Science.gov (United States)

    Majmudar, Trushant; Keaveny, Eric; Shelley, Michael; Zhang, Jun

    2010-11-01

    Undulatory locomotion of microorganisms like soil-dwelling worms and sperm, in structured environments, is ubiquitous in nature. They navigate complex environments consisting of fluids and obstacles, negotiating hydrodynamic effects and geometrical constraints. Here we report experimental observations on the locomotion of C elegans swimming in arrays of micro-pillars in square lattices, with different lattice spacing. We observe that the worm employs a number of different locomotion strategies depending on the lattice spacing. As observed previously in the literature, we uncover regimes of enhanced locomotion, where the velocity is much higher than the free-swimming velocity. In addition, we also observe changes in frequency, velocity, and the gait of the worm as a function of lattice spacing. We also track the worm over time and find that it exhibits super-diffusive behavior and covers a larger area by utilizing the obstacles. These results may have significant impact on the foraging behavior of the worm in its natural environment. Our experimental approach, in conjunction with modeling and simulations, allows us to disentangle the effects of structure and hydrodynamics for an undulating microorganism.

  18. Evidence for Motor Simulation in Imagined Locomotion

    Science.gov (United States)

    Kunz, Benjamin R.; Creem-Regehr, Sarah H.; Thompson, William B.

    2009-01-01

    A series of experiments examined the role of the motor system in imagined movement, finding a strong relationship between imagined walking performance and the biomechanical information available during actual walking. Experiments 1 through 4 established the finding that real and imagined locomotion differ in absolute walking time. We then tested…

  19. Muscle spindle and fusimotor activity in locomotion.

    Science.gov (United States)

    Ellaway, Peter H; Taylor, Anthony; Durbaba, Rade

    2015-08-01

    Mammals may exhibit different forms of locomotion even within a species. A particular form of locomotion (e.g. walk, run, bound) appears to be selected by supraspinal commands, but the precise pattern, i.e. phasing of limbs and muscles, is generated within the spinal cord by so-called central pattern generators. Peripheral sense organs, particularly the muscle spindle, play a crucial role in modulating the central pattern generator output. In turn, the feedback from muscle spindles is itself modulated by static and dynamic fusimotor (gamma) neurons. The activity of muscle spindle afferents and fusimotor neurons during locomotion in the cat is reviewed here. There is evidence for some alpha-gamma co-activation during locomotion involving static gamma motoneurons. However, both static and dynamic gamma motoneurons show patterns of modulation that are distinct from alpha motoneuron activity. It has been proposed that static gamma activity may drive muscle spindle secondary endings to signal the intended movement to the central nervous system. Dynamic gamma motoneuron drive appears to prime muscle spindle primary endings to signal transitions in phase of the locomotor cycle. These findings come largely from reduced animal preparations (decerebrate) and require confirmation in freely moving intact animals. © 2015 Anatomical Society.

  20. Restless Legs Syndrome and Leg Motor Restlessness in Parkinson's Disease.

    Science.gov (United States)

    Suzuki, Keisuke; Miyamoto, Masayuki; Miyamoto, Tomoyuki; Hirata, Koichi

    2015-01-01

    Sleep disturbances are important nonmotor symptoms in Parkinson's disease (PD) that are associated with a negative impact on quality of life. Restless legs syndrome (RLS), which is characterized by an urge to move the legs accompanied by abnormal leg sensations, can coexist with PD, although the pathophysiology of these disorders appears to be different. RLS and PD both respond favorably to dopaminergic treatment, and several investigators have reported a significant relationship between RLS and PD. Sensory symptoms, pain, motor restlessness, akathisia, and the wearing-off phenomenon observed in PD should be differentiated from RLS. RLS in PD may be confounded by chronic dopaminergic treatment; thus, more studies are needed to investigate RLS in drug-naïve patients with PD. Recently, leg motor restlessness (LMR), which is characterized by an urge to move the legs that does not fulfill the diagnostic criteria for RLS, has been reported to be observed more frequently in de novo patients with PD than in age-matched healthy controls, suggesting that LMR may be a part of sensorimotor symptoms intrinsic to PD. In this paper, we provide an overview of RLS, LMR, and PD and of the relationships among these disorders.

  1. Morphological self stabilization of locomotion gaits: illustration on a few examples from bio-inspired locomotion

    OpenAIRE

    Chevallereau , Christine; Boyer , Frédéric; Porez , Mathieu; Mauny , Johan; Aoustin , Yannick

    2017-01-01

    International audience; — To a large extent, robotics locomotion can be viewed as cyclic motions, named gaits. Due to the high complexity of the locomotion dynamics, to find the control laws that ensure an expected gait and its stability with respect to external perturbations, is a challenging issue for feedback control. To address this issue, a promising way is to take inspiration from animals that intensively exploit the interactions of the passive degrees of freedom of their body with thei...

  2. Near infrared spectroscopy for controlling the quality of distal leg perfusion in remote access cardiopulmonary bypass.

    Science.gov (United States)

    Schachner, Thomas; Bonaros, Nikolaos; Bonatti, Johannes; Kolbitsch, Christian

    2008-12-01

    The prevention of leg ischemia is necessary in all patients undergoing femoral artery cannulation for extracorporeal circulation. Near infrared spectroscopy (NIRS) is an established non-invasive method for measuring tissue oxygen saturation. Ten patients underwent robotically assisted endoscopic coronary surgery or ASD repair on the arrested heart using aortic endo-occlusion catheters. They were monitored by transcutaneous NIRS (placed on both lower legs) for quality control of distal leg perfusion during femoral access cardiopulmonary bypass. The baseline NIRS values were 61 (52-80) on the cannulated side versus 70 (53-80) on the contralateral leg (p=n.s.). During clamping of the femoral artery for installation of the remote access perfusion system the tissue oxygen saturation dropped to 38 (18-58) (p=0.001 vs baseline) while it remained stable on the contralateral leg. After successful implantation of the distal leg perfusion the NIRS values normalized to similar amounts on both legs. We conclude that transcutaneous NIRS of the lower legs might be a useful non-invasive tool for monitoring leg perfusion in patients undergoing extracorporeal circulation via the femoral vessels.

  3. Locomotive Schedule Optimization for Da-qin Heavy Haul Railway

    Directory of Open Access Journals (Sweden)

    Ruiye Su

    2015-01-01

    Full Text Available The main difference between locomotive schedule of heavy haul railways and that of regular rail transportation is the number of locomotives utilized for one train. One heavy-loaded train usually has more than one locomotive, but a regular train only has one. This paper develops an optimization model for the multilocomotive scheduling problem (MLSP through analyzing the current locomotive schedule of Da-qin Railway. The objective function of our paper is to minimize the total number of utilized locomotives. The MLSP is nondeterministic polynomial (NP hard. Therefore, we convert the multilocomotive traction problem into a single-locomotive traction problem. Then, the single-locomotive traction problem (SLTP can be converted into an assignment problem. The Hungarian algorithm is applied to solve the model and obtain the optimal locomotive schedule. We use the variance of detention time of locomotives at stations to evaluate the stability of locomotive schedule. In order to evaluate the effectiveness of the proposed optimization model, case studies for 20 kt and 30 kt heavy-loaded combined trains on Da-qin Railway are both conducted. Compared to the current schedules, the optimal schedules from the proposed models can save 62 and 47 locomotives for 20 kt and 30 kt heavy-loaded combined trains, respectively. Therefore, the effectiveness of the proposed model and its solution algorithm are both valid.

  4. Restless legs syndrome and periodic leg movements of sleep.

    Science.gov (United States)

    Rye, David B; Trotti, Lynn Marie

    2012-11-01

    Women are more commonly affected than men by restless legs syndrome, and prevalence is highest amongst those of northern European heritage. The motor manifestations include nonvolitional myoclonus (periodic leg movements). Disinhibition of spinal sensorimotor circuits may underlie these primary features and can be affected by peripheral as well as supraspinal networks. Insufficient mobilizable iron stores increase expressivity in some individuals. The sensorimotor features are relieved by dopamine, especially dopamine agonists, gabapentin and its derivatives, and opioids. A diagnosis relies on recognition of key primary and supportive features, and treatments are generally well tolerated, efficacious, and life-changing. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. Development of a Novel Locomotion Algorithm for Snake Robot

    International Nuclear Information System (INIS)

    Khan, Raisuddin; Billah, Md Masum; Watanabe, Mitsuru; Shafie, A A

    2013-01-01

    A novel algorithm for snake robot locomotion is developed and analyzed in this paper. Serpentine is one of the renowned locomotion for snake robot in disaster recovery mission to overcome narrow space navigation. Several locomotion for snake navigation, such as concertina or rectilinear may be suitable for narrow spaces, but is highly inefficient if the same type of locomotion is used even in open spaces resulting friction reduction which make difficulties for snake movement. A novel locomotion algorithm has been proposed based on the modification of the multi-link snake robot, the modifications include alterations to the snake segments as well elements that mimic scales on the underside of the snake body. Snake robot can be able to navigate in the narrow space using this developed locomotion algorithm. The developed algorithm surmount the others locomotion limitation in narrow space navigation

  6. Effects of locomotion extend throughout the mouse early visual system.

    Science.gov (United States)

    Erisken, Sinem; Vaiceliunaite, Agne; Jurjut, Ovidiu; Fiorini, Matilde; Katzner, Steffen; Busse, Laura

    2014-12-15

    Neural responses in visual cortex depend not only on sensory input but also on behavioral context. One such context is locomotion, which modulates single-neuron activity in primary visual cortex (V1). How locomotion affects neuronal populations across cortical layers and in precortical structures is not well understood. We performed extracellular multielectrode recordings in the visual system of mice during locomotion and stationary periods. We found that locomotion influenced activity of V1 neurons with a characteristic laminar profile and shaped the population response by reducing pairwise correlations. Although the reduction of pairwise correlations was restricted to cortex, locomotion slightly but consistently increased firing rates and controlled tuning selectivity already in the dorsolateral geniculate nucleus (dLGN) of the thalamus. At the level of the eye, increases in locomotion speed were associated with pupil dilation. These findings document further, nonmultiplicative effects of locomotion, reaching earlier processing stages than cortex. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Passive Control of Attachment in Legged Space Robots

    Directory of Open Access Journals (Sweden)

    Alessandro Gasparetto

    2010-01-01

    Full Text Available In the space environment the absence of gravity calls for constant safe attachment of any loose object, but the low-pressure conditions prohibit the use of glue-type adhesives. The attachment system of freely hunting spiders, e.g. Evarcha arcuata, employs van der Waals forces and mechanical interlocking. Furthermore, detachment is achieved passively and requires little force. Hence, the spider serves as a model for a versatile legged robot for space applications, e.g. on the outer surface of a space station. In this paper, we analyse the dry attachment systems of E. arcuata and geckos as well as the kinematics of freely hunting spiders. We generalise the results of biological studies on spider locomotion and mobility, including the major movement and the position constraints set by the dry adhesion system. From these results, we define a simplified spider model and study the overall kinematics of the legs both in flight and in contact with the surface. The kinematic model, the data on spider gait characteristics and the adhesion constraints are implemented in a kinematic simulator. The simulator results confirm the principal functionality of our concept.

  8. Promethus Hot Leg Piping Concept

    International Nuclear Information System (INIS)

    AM Girbik; PA Dilorenzo

    2006-01-01

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept

  9. Leg ulcers due to hyperhomocysteinemia

    Directory of Open Access Journals (Sweden)

    Krupa Shankar D

    2006-01-01

    Full Text Available Chronic leg ulcers are rare in young adults and generally indicate a vascular cause. We report a case of a 26-year-old man with leg ulcers of eight months duration. Doppler study indicated venous incompetence and a postphlebitic limb. However, as the distribution and number of ulcers was not consistent with stasis alone and no features of collagen vascular disease were noted, a hyperviscosity state was considered and confirmed with significantly elevated homocysteine level in the serum. Administration of vitamins B1, B2, B6 and B12, trimethyl-glycine, mecobalamine, folic acid and povidone iodine dressings with culture-directed antibiotic therapy led to a satisfactory healing of ulcers over a period of one month. Hyperhomocysteinemia must be considered in the differential diagnosis of leg ulcers in young individuals.

  10. An fMRI pilot study to evaluate brain activation associated with locomotion adaptation.

    Science.gov (United States)

    Marchal-Crespo, Laura; Hollnagel, Christoph; Brügger, Mike; Kollias, Spyros; Riener, Robert

    2011-01-01

    The goal of robotic therapy is to provoke motor plasticity via the application of robotic training strategies. Although robotic haptic guidance is the commonly used motor-training strategy to reduce performance errors while training, research on motor learning has emphasized that errors are a fundamental neural signal that drives motor adaptation. Thus, researchers have proposed robotic therapy algorithms that amplify movement errors rather than decrease them. Studying the particular brain regions involved in learning under different training strategies might help tailoring motor training conditions to the anatomical location of a focal brain insult. In this paper, we evaluate the brain regions involved in locomotion adaptation when training with three different conditions: without robotic guidance, with a random-varying force disturbance, and with repulsive forces proportional to errors. We performed an fMRI pilot study with four healthy subjects who stepped in an fMRI compatible walking robotic device. Subjects were instructed to actively synchronize their left leg with respect to their right leg (passively guided by the robot) while their left leg was affected by any of the three conditions. We observed activation in areas known to be involved in error processing. Although we found that all conditions required the similar cortical network to fulfill the task, we observed a tendency towards more activity in the motor/sensory network as more "challenged" the subjects were. © 2011 IEEE

  11. Trajectory Correction and Locomotion Analysis of a Hexapod Walking Robot with Semi-Round Rigid Feet.

    Science.gov (United States)

    Zhu, Yaguang; Jin, Bo; Wu, Yongsheng; Guo, Tong; Zhao, Xiangmo

    2016-08-31

    Aimed at solving the misplaced body trajectory problem caused by the rolling of semi-round rigid feet when a robot is walking, a legged kinematic trajectory correction methodology based on the Least Squares Support Vector Machine (LS-SVM) is proposed. The concept of ideal foothold is put forward for the three-dimensional kinematic model modification of a robot leg, and the deviation value between the ideal foothold and real foothold is analyzed. The forward/inverse kinematic solutions between the ideal foothold and joint angular vectors are formulated and the problem of direct/inverse kinematic nonlinear mapping is solved by using the LS-SVM. Compared with the previous approximation method, this correction methodology has better accuracy and faster calculation speed with regards to inverse kinematics solutions. Experiments on a leg platform and a hexapod walking robot are conducted with multi-sensors for the analysis of foot tip trajectory, base joint vibration, contact force impact, direction deviation, and power consumption, respectively. The comparative analysis shows that the trajectory correction methodology can effectively correct the joint trajectory, thus eliminating the contact force influence of semi-round rigid feet, significantly improving the locomotion of the walking robot and reducing the total power consumption of the system.

  12. Trajectory Correction and Locomotion Analysis of a Hexapod Walking Robot with Semi-Round Rigid Feet

    Directory of Open Access Journals (Sweden)

    Yaguang Zhu

    2016-08-01

    Full Text Available Aimed at solving the misplaced body trajectory problem caused by the rolling of semi-round rigid feet when a robot is walking, a legged kinematic trajectory correction methodology based on the Least Squares Support Vector Machine (LS-SVM is proposed. The concept of ideal foothold is put forward for the three-dimensional kinematic model modification of a robot leg, and the deviation value between the ideal foothold and real foothold is analyzed. The forward/inverse kinematic solutions between the ideal foothold and joint angular vectors are formulated and the problem of direct/inverse kinematic nonlinear mapping is solved by using the LS-SVM. Compared with the previous approximation method, this correction methodology has better accuracy and faster calculation speed with regards to inverse kinematics solutions. Experiments on a leg platform and a hexapod walking robot are conducted with multi-sensors for the analysis of foot tip trajectory, base joint vibration, contact force impact, direction deviation, and power consumption, respectively. The comparative analysis shows that the trajectory correction methodology can effectively correct the joint trajectory, thus eliminating the contact force influence of semi-round rigid feet, significantly improving the locomotion of the walking robot and reducing the total power consumption of the system.

  13. [Job stress in locomotive attendants in a locomotive depot and related influencing factors].

    Science.gov (United States)

    Kang, L; Jia, X C; Lu, F; Zhou, W H; Chen, R

    2017-10-20

    Objective: To investigate the current status of job stress in locomotive attendants in a locomotive depot and related influencing factors. Methods: From 2012 to 2013, cluster sampling was used to select 1500 locomotive attendants in a locomotive depot in Zhengzhou Railway Bureau as respondents.The contents of the investigation included general data and occupational information.A job satisfaction questionnaire was used to investigate the degree of satisfaction, a depression scale was used to investigate the frequency of symptoms, and a daily stress scale was used to investigate the frequency of fatigue and stress. Results: There was a significant difference in depression score between locomotive attendants with different ages, working years, degrees of education, working situations of spouse, total monthly family incomes, numbers of times of attendanceat night, monthly numbers of times of attendance,ormonthly attendance times( P job satisfaction score between locomotive attendants with different ages,working years, degrees of education, working situations of spouse, total monthly family incomes, numbers of times of attendance at night, monthly attendance times,or ways to work( P job satisfaction( β =1.546)and monthly number of times of attendance,working years,attendance time at night,and degree of education were negatively correlated with job satisfaction( β =-0.185,-0.097,-0.020,and -1.106); monthly number of times of attendance andcommute time were positively correlated with depression( β =0.243 and 0.029); attendance time at night,working situation of spouse,commute time,monthly number of times of attendance,degree of education,and working years were positively correlated with daily stress( β =0.006,0.473,0.010,0.043,0.585, and 0.028). Conclusion: Number of times of attendance, attendance time,working years,and spouse are influencing factors for job stress in locomotive attendants. Improvement in work process and care for their personal life help to reduce

  14. Cross-legged Gods and One-legged Foresters

    NARCIS (Netherlands)

    Petrovskaia, N.I.

    The present article is a re-evaluation of a marvellous element in a medieval Welsh romance, Chwedl Iarlles y Ffynnawn ‘Tale of the Lady of the Fountain’, also known as Owein. One of the characters encountered by the hero is a one-eyed one-legged dark giant forester who appears to have a particular

  15. Efficient worm-like locomotion: slip and control of soft-bodied peristaltic robots.

    Science.gov (United States)

    Daltorio, Kathryn A; Boxerbaum, Alexander S; Horchler, Andrew D; Shaw, Kendrick M; Chiel, Hillel J; Quinn, Roger D

    2013-09-01

    In this work, we present a dynamic simulation of an earthworm-like robot moving in a pipe with radially symmetric Coulomb friction contact. Under these conditions, peristaltic locomotion is efficient if slip is minimized. We characterize ways to reduce slip-related losses in a constant-radius pipe. Using these principles, we can design controllers that can navigate pipes even with a narrowing in radius. We propose a stable heteroclinic channel controller that takes advantage of contact force feedback on each segment. In an example narrowing pipe, this controller loses 40% less energy to slip compared to the best-fit sine wave controller. The peristaltic locomotion with feedback also has greater speed and more consistent forward progress

  16. Design of a biped locomotion controller based on adaptive neuro-fuzzy inference systems

    Energy Technology Data Exchange (ETDEWEB)

    Shieh, M-Y; Chang, K-H [Department of E. E., Southern Taiwan University, 1 Nantai St., YungKang City, Tainan County 71005, Taiwan (China); Lia, Y-S [Executive Director Office, ITRI, Southern Taiwan Innovation Park, Tainan County, Taiwan (China)], E-mail: myshieh@mail.stut.edu.tw

    2008-02-15

    This paper proposes a method for the design of a biped locomotion controller based on the ANFIS (Adaptive Neuro-Fuzzy Inference System) inverse learning model. In the model developed here, an integrated ANFIS structure is trained to function as the system identifier for the modeling of the inverse dynamics of a biped robot. The parameters resulting from the modeling process are duplicated and integrated as those of the biped locomotion controller to provide favorable control action. As the simulation results show, the proposed controller is able to generate a stable walking cycle for a biped robot. Moreover, the experimental results demonstrate that the performance of the proposed controller is satisfactory under conditions when the robot stands in different postures or moves on a rugged surface.

  17. Design of a biped locomotion controller based on adaptive neuro-fuzzy inference systems

    Science.gov (United States)

    Shieh, M.-Y.; Chang, K.-H.; Lia, Y.-S.

    2008-02-01

    This paper proposes a method for the design of a biped locomotion controller based on the ANFIS (Adaptive Neuro-Fuzzy Inference System) inverse learning model. In the model developed here, an integrated ANFIS structure is trained to function as the system identifier for the modeling of the inverse dynamics of a biped robot. The parameters resulting from the modeling process are duplicated and integrated as those of the biped locomotion controller to provide favorable control action. As the simulation results show, the proposed controller is able to generate a stable walking cycle for a biped robot. Moreover, the experimental results demonstrate that the performance of the proposed controller is satisfactory under conditions when the robot stands in different postures or moves on a rugged surface.

  18. The one-leg standing radiograph

    OpenAIRE

    Pinsornsak, P.; Naratrikun, K.; Kanitnate, S.; Sangkomkamhang, T.

    2016-01-01

    Objectives The purpose of this study was to compare the joint space width between one-leg and both-legs standing radiographs in order to diagnose a primary osteoarthritis of the knee. Methods Digital radiographs of 100 medial osteoarthritic knees in 50 patients were performed. The patients had undergone one-leg standing anteroposterior (AP) views by standing on the affected leg while a both-legs standing AP view was undertaken while standing on both legs. The severity of the osteoarthritis wa...

  19. Locomotion control of hybrid cockroach robots

    Science.gov (United States)

    Sanchez, Carlos J.; Chiu, Chen-Wei; Zhou, Yan; González, Jorge M.; Vinson, S. Bradleigh; Liang, Hong

    2015-01-01

    Natural systems retain significant advantages over engineered systems in many aspects, including size and versatility. In this research, we develop a hybrid robotic system using American (Periplaneta americana) and discoid (Blaberus discoidalis) cockroaches that uses the natural locomotion and robustness of the insect. A tethered control system was firstly characterized using American cockroaches, wherein implanted electrodes were used to apply an electrical stimulus to the prothoracic ganglia. Using this approach, larger discoid cockroaches were engineered into a remotely controlled hybrid robotic system. Locomotion control was achieved through electrical stimulation of the prothoracic ganglia, via a remotely operated backpack system and implanted electrodes. The backpack consisted of a microcontroller with integrated transceiver protocol, and a rechargeable battery. The hybrid discoid roach was able to walk, and turn in response to an electrical stimulus to its nervous system with high repeatability of 60%. PMID:25740855

  20. Using entropy measures to characterize human locomotion.

    Science.gov (United States)

    Leverick, Graham; Szturm, Tony; Wu, Christine Q

    2014-12-01

    Entropy measures have been widely used to quantify the complexity of theoretical and experimental dynamical systems. In this paper, the value of using entropy measures to characterize human locomotion is demonstrated based on their construct validity, predictive validity in a simple model of human walking and convergent validity in an experimental study. Results show that four of the five considered entropy measures increase meaningfully with the increased probability of falling in a simple passive bipedal walker model. The same four entropy measures also experienced statistically significant increases in response to increasing age and gait impairment caused by cognitive interference in an experimental study. Of the considered entropy measures, the proposed quantized dynamical entropy (QDE) and quantization-based approximation of sample entropy (QASE) offered the best combination of sensitivity to changes in gait dynamics and computational efficiency. Based on these results, entropy appears to be a viable candidate for assessing the stability of human locomotion.

  1. Serpentine locomotion through elastic energy release

    OpenAIRE

    Dal Corso, Francesco; Misseroni, Diego; Pugno, Nicola; Movchan, A. B.; Movchan, N. V.; Bigoni, Davide

    2017-01-01

    A model for serpentine locomotion is derived from a novel perspective based on concepts from configurational mechanics. The motion is realized through the release of the elastic energy of a deformable rod, sliding inside a frictionless channel, which represents a snake moving against lateral restraints. A new formulation is presented, correcting previous results and including situations never analysed so far, as in the cases when the serpent's body lies only partially inside the restraining c...

  2. On the rules for aquatic locomotion

    Science.gov (United States)

    Saadat, M.; Fish, F. E.; Domel, A. G.; Di Santo, V.; Lauder, G. V.; Haj-Hariri, H.

    2017-08-01

    We present unifying rules governing the efficient locomotion of swimming fish and marine mammals. Using scaling and dimensional analysis, supported by new experimental data, we show that efficient locomotion occurs when the values of the Strouhal (St) number St (=f A /U ) and A*(=A /L ) , two nondimensional numbers that relate forward speed U , tail-beat amplitude A , tail-beat frequency f , and the length of the swimmer L are bound to the tight ranges of 0.2-0.4 and 0.1-0.3, respectively. The tight range of 0.2-0.4 for the St number has previously been associated with optimal thrust generation. We show that the St number alone is insufficient to achieve optimal aquatic locomotion, and an additional condition on A* is needed. More importantly, we show that when swimming at minimal power consumption, the Strouhal number of a cruising swimmer is predetermined solely by the shape and drag characteristics of the swimmer. We show that diverse species of fish and cetaceans cruise indeed with the St number and A* predicted by our theory. Our findings provide a physical explanation as to why fast aquatic swimmers cruise with a relatively constant tail-beat amplitude of approximately 20% of the body length, and their swimming speed is nearly proportional to their tail-beat frequency.

  3. Back Pain with Leg Pain.

    Science.gov (United States)

    Vulfsons, Simon; Bar, Negev; Eisenberg, Elon

    2017-07-01

    The clinical diagnostic dilemma of low back pain that is associated with lower limb pain is very common. In relation to back pain that radiates to the leg, the International Association for the Study of Pain (IASP) states: "Pain in the lower limb should be described specifically as either referred pain or radicular pain. In cases of doubt no implication should be made and the pain should be described as pain in the lower limb." Bogduks' editorial in the journal PAIN (2009) helps us to differentiate and define the terms somatic referred pain, radicular pain, and radiculopathy. In addition, there are other pathologies distal to the nerve root that could be relevant to patients with back pain and leg pain such as plexus and peripheral nerve involvement. Hence, the diagnosis of back pain with leg pain can still be challenging. In this article, we present a patient with back and leg pain. The patient appears to have a radicular pain syndrome, but has no neurological impairment and shows signs of myofascial involvement. Is there a single diagnosis or indeed two overlapping syndromes? The scope of our article encompasses the common diagnostic possibilities for this type of patient. A discussion of treatment is beyond the scope of this article and depends on the final diagnosis/diagnoses made.

  4. Kan leg skabe fremtidens vindere?

    DEFF Research Database (Denmark)

    Holm, Claus

    2006-01-01

    Dansk Boldspil Union skruer ned for den præstationsorienterede tilgang til børnefodbold. I stedet skal børnenes leg med bolden i fokus. Målet er at forhindre massivt frafald i børne- og ungdomsfodbolden og højne niveauet hos topspillerne....

  5. Biomechanics of the Treadmill Locomotion on the International Space Station

    Science.gov (United States)

    DeWitt, John; Cromwell, R. L.; Ploutz-Snyder, L. L.

    2014-01-01

    Exercise prescriptions completed by International Space Station (ISS) crewmembers are typically based upon evidence obtained during ground-based investigations, with the assumption that the results of long-term training in weightlessness will be similar to that attained in normal gravity. Coupled with this supposition are the assumptions that exercise motions and external loading are also similar between gravitational environments. Normal control of locomotion is dependent upon learning patterns of muscular activation and requires continual monitoring of internal and external sensory input [1]. Internal sensory input includes signals that may be dependent on or independent of gravity. Bernstein hypothesized that movement strategy planning and execution must include the consideration of segmental weights and inertia [2]. Studies of arm movements in microgravity showed that individuals tend to make errors but that compensation strategies result in adaptations, suggesting that control mechanisms must include peripheral information [3-5]. To date, however, there have been no studies examining a gross motor activity such as running in weightlessness other than using microgravity analogs [6-8]. The objective of this evaluation was to collect biomechanical data from crewmembers during treadmill exercise before and during flight. The goal was to determine locomotive biomechanics similarities and differences between normal and weightless environments. The data will be used to optimize future exercise prescriptions. This project addresses the Critical Path Roadmap risks 1 (Accelerated Bone Loss and Fracture Risk) and 11 (Reduced Muscle Mass, Strength, and Endurance). Data were collected from 7 crewmembers before flight and during their ISS missions. Before launch, crewmembers performed a single data collection session at the NASA Johnson Space Center. Three-dimensional motion capture data were collected for 30 s at speeds ranging from 1.5 to 9.5 mph in 0.5 mph increments

  6. Doppler ultrasound exam of an arm or leg

    Science.gov (United States)

    Peripheral vascular disease - Doppler; PVD - Doppler; PAD - Doppler; Blockage of leg arteries - Doppler; Intermittent claudication - Doppler; Arterial insufficiency of the legs - Doppler; Leg pain and ...

  7. Stable particles

    International Nuclear Information System (INIS)

    Samios, N.P.

    1994-01-01

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets, with a few more additions - with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers - exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the foree of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc. (orig.)

  8. Stable particles

    International Nuclear Information System (INIS)

    Samios, N.P.

    1993-01-01

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc

  9. Gait Planning Research for an Electrically Driven Large-Load-Ratio Six-Legged Robot

    Directory of Open Access Journals (Sweden)

    Hong-Chao Zhuang

    2017-03-01

    Full Text Available Gait planning is an important basis for the walking of a legged robot. To improve the walking stability of multi-legged robots and to reduce the impact force between the foot and the ground, gait planning strategies are presented for an electrically driven large-load-ratio six-legged robot. First, the configuration and walking gait of the electrically driven large-load-ratio six-legged robot are designed. The higher-stable swing sequences of legs and typical walking modes are respectively obtained. Based on the Denavit–Hartenberg (D–H method, the analyses of the forward and inverse kinematics are implemented. The mathematical models of the articulated rotation angles are respectively established. In view of the buffer device installed at the end of shin to decrease the impact force between the foot and the ground, an initial lift height of the leg is brought into gait planning when the support phase changes into the transfer phase. The mathematical models of foot trajectories are established. Finally, a prototype of the electrically driven large-load-ratio six-legged robot is developed. The experiments of the prototype are carried out regarding the aspects of the walking speed and surmounting obstacle. Then, the reasonableness of gait planning is verified based on the experimental results. The proposed strategies of gait planning lay the foundation for effectively reducing the foot–ground impact force and can provide a reference for other large-load-ratio multi-legged robots.

  10. Neurobiology of Caenorhabditis elegans Locomotion: Where Do We Stand?

    Science.gov (United States)

    Gjorgjieva, Julijana; Biron, David; Haspel, Gal

    2014-01-01

    Animals use a nervous system for locomotion in some stage of their life cycle. The nematode Caenorhabditis elegans, a major animal model for almost all fields of experimental biology, has long been used for detailed studies of genetic and physiological locomotion mechanisms. Of its 959 somatic cells, 302 are neurons that are identifiable by lineage, location, morphology, and neurochemistry in every adult hermaphrodite. Of those, 75 motoneurons innervate body wall muscles that provide the thrust during locomotion. In this Overview, we concentrate on the generation of either forward- or backward-directed motion during crawling and swimming. We describe locomotion behavior, the parts constituting the locomotion system, and the relevant neuronal connectivity. Because it is not yet fully understood how these components combine to generate locomotion, we discuss competing hypotheses and models. PMID:26955070

  11. Serotonin Influences Locomotion in the Nudibranch Mollusc Melibe leonina

    OpenAIRE

    LEWIS, STEFANIE L.; LYONS, DEBORAH E.; MEEKINS, TIFFANIE L.; NEWCOMB, JAMES M.

    2011-01-01

    Serotonin (5-HT) influences locomotion in many animals, from flatworms to mammals. This study examined the effects of 5-HT on locomotion in the nudibranch mollusc Melibe leonina (Gould, 1852). M. leonina exhibits two modes of locomotion, crawling and swimming. Animals were bath-immersed in a range of concentrations of 5-HT or injected with various 5-HT solutions into the hemolymph and then monitored for locomotor activity. In contrast to other gastropods studied, M. leonina showed no signific...

  12. Associations of conformation and locomotive characteristics in growing gilts with osteochondrosis at slaughter.

    Science.gov (United States)

    de Koning, D B; van Grevenhof, E M; Laurenssen, B F A; Hazeleger, W; Kemp, B

    2015-01-01

    Osteochondrosis (OC) and abnormalities in conformation and locomotive characteristics (CLC) have been associated with premature culling in sows. Several CLC have been suggested to be associated with OC and might help as an in vivo indicator for and increased risk of having OC. The aim of this study was to investigate associations of OC with CLC assessed at several ages in growing gilts from 2 separate experiments over the effects of dietary restriction (Exp. 1) and floor type (Exp. 2) on OC prevalence. In Exp. 1, gilts (n = 211) were subjectively assessed for CLC at, on average, 4, 9, 11, 16, and 24 wk of age. In Exp. 2, gilts (n = 212) were subjectively assessed for CLC at, on average, 4, 9, 11, 16, and 22 wk of age. Assessment was done on 10 conformation and 2 locomotive characteristics using a 9-point grading scale by 2 observers. At, on average, 27 wk of age in Exp. 1 and 24 wk of age in Exp. 2, gilts were slaughtered and the knee, elbow, and hock joints were macroscopically assessed for OC. The CLC most frequently associated with OC were O shape or X shape of the hind legs, straight or bowed hind legs, and straight or sickled hock. X-shaped hind legs were associated with OC at slaughter in the knee joint at 4, 9, and 24 wk of age and at the animal level (all joints taken together) at 4, 9, and 16 wk of age. Straight or bowed hind legs were associated with OC at slaughter in the knee joint at 4 and 11 wk of age; in the hock joint at 11 wk of age; and at the animal level at 4, 9, 11, and 22 wk of age. Straight or sickled hock was associated with OC at slaughter in the knee joint at 4 wk of age, in the hock joint at 9 and 22 wk of age, and at the animal level at 9 and 22 wk of age. Results show that several CLC assessed at several ages were associated with OC, but consistent associations of a type of CLC in every assessment could not be found. The associations of CLC with OC are, therefore, difficult to be used as an in vivo indicator of increased risk for OC.

  13. A comparison of one-legged and two-legged countermovement jumps

    NARCIS (Netherlands)

    van Soest, A J; Roebroeck, M.E.; Bobbert, M F; Huijing, P A; van Ingen Schenau, G J

    1985-01-01

    Ten well-trained male volleyball players performed one-legged and two-legged vertical countermovement jumps. Ground reaction forces, cinematographic data, and electromyographic data were recorded. Jumping height in one-legged jumps was 58.5% of that reached in two-legged jumps. Mean net torques in

  14. A measured-ZMP(Zero-Moment-Point)-referenced control of biped locomotion robots

    International Nuclear Information System (INIS)

    Kume, Etsuo; Akimoto, Masayuki

    1994-01-01

    For the control of biped locomotion, the model-referenced-control or programmed control method is widely used. In this method, the instantaneous torque of actuator equipped at each joint is controlled so as to equalize measured angle to input joint angle based on the prescribed motion. The drawback is that this method can not deal with the dynamic change of walking such as that due to unknown external force. To resolve such the drawback, we propose a new control method as follows: given a prescribed motion as a set of gait, namely gait of starting walk, cyclic walk, and stopping walk including a standard trajectory of the Zero-Moment-Point (ZMP), the trunk motion to compensate the legs' motion is generated in real time using the current ZMP measured by sensing device. The proposed method will be validated through some numerical simulations. (author)

  15. Multi-Locomotion Robotic Systems New Concepts of Bio-inspired Robotics

    CERN Document Server

    Fukuda, Toshio; Sekiyama, Kosuke; Aoyama, Tadayoshi

    2012-01-01

    Nowadays, multiple attention have been paid on a robot working in the human living environment, such as in the field of medical, welfare, entertainment and so on. Various types of researches are being conducted actively in a variety of fields such as artificial intelligence, cognitive engineering, sensor- technology, interfaces and motion control. In the future, it is expected to realize super high functional human-like robot by integrating technologies in various fields including these types of researches. The book represents new developments and advances in the field of bio-inspired robotics research introducing the state of the art, the idea of multi-locomotion robotic system to implement the diversity of animal motion. It covers theoretical and computational aspects of Passive Dynamic Autonomous Control (PDAC), robot motion control, multi legged walking and climbing as well as brachiation focusing concrete robot systems, components and applications. In addition, gorilla type robot systems are described as...

  16. A contribution about ferrofluid based flow manipulation and locomotion systems

    International Nuclear Information System (INIS)

    Zimmermann, K; Zeidis, I; Bohm, V; Popp, J

    2009-01-01

    With the background of developing apedal bionic inspired locomotion systems for future application fields like autonomous (swarm) robots, medical engineering and inspection systems, this article presents a selection of locomotion systems with bifluidic flow control using ferrofluid. By controlling the change of shape, position and pressure of the ferrofluid in a secondary low viscous fluid by magnetic fields locomotion of objects or the ferrofluid itself can be realised. The locomotion of an object is caused in the first example by a ferrofluid generated flow of the secondary fluid and in the second and third case by the direct alteration of the ferrofluid position.

  17. A contribution about ferrofluid based flow manipulation and locomotion systems

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, K; Zeidis, I; Bohm, V; Popp, J [TU Ilmenau, Fak. f. Maschinenbau, FG Technische Mechanik, Max-Planck-Ring 12, 98693 Ilmenau (Germany)], E-mail: klaus.zimmermann@tu-ilmenau.de, E-mail: jana.popp@tu-ilmenau.de

    2009-02-01

    With the background of developing apedal bionic inspired locomotion systems for future application fields like autonomous (swarm) robots, medical engineering and inspection systems, this article presents a selection of locomotion systems with bifluidic flow control using ferrofluid. By controlling the change of shape, position and pressure of the ferrofluid in a secondary low viscous fluid by magnetic fields locomotion of objects or the ferrofluid itself can be realised. The locomotion of an object is caused in the first example by a ferrofluid generated flow of the secondary fluid and in the second and third case by the direct alteration of the ferrofluid position.

  18. LFP Oscillations in the Mesencephalic Locomotor Region during Voluntary Locomotion

    Directory of Open Access Journals (Sweden)

    Brian R. Noga

    2017-05-01

    Full Text Available Oscillatory rhythms in local field potentials (LFPs are thought to coherently bind cooperating neuronal ensembles to produce behaviors, including locomotion. LFPs recorded from sites that trigger locomotion have been used as a basis for identification of appropriate targets for deep brain stimulation (DBS to enhance locomotor recovery in patients with gait disorders. Theta band activity (6–12 Hz is associated with locomotor activity in locomotion-inducing sites in the hypothalamus and in the hippocampus, but the LFPs that occur in the functionally defined mesencephalic locomotor region (MLR during locomotion have not been determined. Here we record the oscillatory activity during treadmill locomotion in MLR sites effective for inducing locomotion with electrical stimulation in rats. The results show the presence of oscillatory theta rhythms in the LFPs recorded from the most effective MLR stimulus sites (at threshold ≤60 μA. Theta activity increased at the onset of locomotion, and its power was correlated with the speed of locomotion. In animals with higher thresholds (>60 μA, the correlation between locomotor speed and theta LFP oscillations was less robust. Changes in the gamma band (previously recorded in vitro in the pedunculopontine nucleus (PPN, thought to be a part of the MLR were relatively small. Controlled locomotion was best achieved at 10–20 Hz frequencies of MLR stimulation. Our results indicate that theta and not delta or gamma band oscillation is a suitable biomarker for identifying the functional MLR sites.

  19. The need for speed in rodent locomotion analyses.

    Science.gov (United States)

    Batka, Richard J; Brown, Todd J; Mcmillan, Kathryn P; Meadows, Rena M; Jones, Kathryn J; Haulcomb, Melissa M

    2014-10-01

    Locomotion analysis is now widely used across many animal species to understand the motor defects in disease, functional recovery following neural injury, and the effectiveness of various treatments. More recently, rodent locomotion analysis has become an increasingly popular method in a diverse range of research. Speed is an inseparable aspect of locomotion that is still not fully understood, and its effects are often not properly incorporated while analyzing data. In this hybrid manuscript, we accomplish three things: (1) review the interaction between speed and locomotion variables in rodent studies, (2) comprehensively analyze the relationship between speed and 162 locomotion variables in a group of 16 wild-type mice using the CatWalk gait analysis system, and (3) develop and test a statistical method in which locomotion variables are analyzed and reported in the context of speed. Notable results include the following: (1) over 90% of variables, reported by CatWalk, were dependent on speed with an average R(2) value of 0.624, (2) most variables were related to speed in a nonlinear manner, (3) current methods of controlling for speed are insufficient, and (4) the linear mixed model is an appropriate and effective statistical method for locomotion analyses that is inclusive of speed-dependent relationships. Given the pervasive dependency of locomotion variables on speed, we maintain that valid conclusions from locomotion analyses cannot be made unless they are analyzed and reported within the context of speed. © 2014 Wiley Periodicals, Inc.

  20. LFP Oscillations in the Mesencephalic Locomotor Region during Voluntary Locomotion.

    Science.gov (United States)

    Noga, Brian R; Sanchez, Francisco J; Villamil, Luz M; O'Toole, Christopher; Kasicki, Stefan; Olszewski, Maciej; Cabaj, Anna M; Majczyński, Henryk; Sławińska, Urszula; Jordan, Larry M

    2017-01-01

    Oscillatory rhythms in local field potentials (LFPs) are thought to coherently bind cooperating neuronal ensembles to produce behaviors, including locomotion. LFPs recorded from sites that trigger locomotion have been used as a basis for identification of appropriate targets for deep brain stimulation (DBS) to enhance locomotor recovery in patients with gait disorders. Theta band activity (6-12 Hz) is associated with locomotor activity in locomotion-inducing sites in the hypothalamus and in the hippocampus, but the LFPs that occur in the functionally defined mesencephalic locomotor region (MLR) during locomotion have not been determined. Here we record the oscillatory activity during treadmill locomotion in MLR sites effective for inducing locomotion with electrical stimulation in rats. The results show the presence of oscillatory theta rhythms in the LFPs recorded from the most effective MLR stimulus sites (at threshold ≤60 μA). Theta activity increased at the onset of locomotion, and its power was correlated with the speed of locomotion. In animals with higher thresholds (>60 μA), the correlation between locomotor speed and theta LFP oscillations was less robust. Changes in the gamma band (previously recorded in vitro in the pedunculopontine nucleus (PPN), thought to be a part of the MLR) were relatively small. Controlled locomotion was best achieved at 10-20 Hz frequencies of MLR stimulation. Our results indicate that theta and not delta or gamma band oscillation is a suitable biomarker for identifying the functional MLR sites.

  1. [Restless legs syndrome and nocturnal leg pain : Differential diagnosis and treatment].

    Science.gov (United States)

    Hornyak, M; Stiasny-Kolster, K; Evers, S; Happe, S

    2011-09-01

    Pain in the legs belongs to the five most frequent regional pain symptoms. Restless legs syndrome (RLS) presents a particular differential diagnosis for pain in the legs, which is characterized by a nocturnal urge to move the legs often associated with painful sensations in the legs. It is one of the most common neurological disorders and probably the leading cause of nocturnal pain in the legs. In this overview, the diagnosis and therapy of RLS as well as aspects of pain therapy of the disorder are presented. In addition, the differential diagnoses for exclusion of other specific causes of nocturnal pain in the legs are discussed.

  2. Locomotion in extinct giant kangaroos: were sthenurines hop-less monsters?

    Directory of Open Access Journals (Sweden)

    Christine M Janis

    Full Text Available Sthenurine kangaroos (Marsupialia, Diprotodontia, Macropodoidea were an extinct subfamily within the family Macropodidae (kangaroos and rat-kangaroos. These "short-faced browsers" first appeared in the middle Miocene, and radiated in the Plio-Pleistocene into a diversity of mostly large-bodied forms, more robust than extant forms in their build. The largest (Procoptodon goliah had an estimated body mass of 240 kg, almost three times the size of the largest living kangaroos, and there is speculation whether a kangaroo of this size would be biomechanically capable of hopping locomotion. Previously described aspects of sthenurine anatomy (specialized forelimbs, rigid lumbar spine would limit their ability to perform the characteristic kangaroo pentapedal walking (using the tail as a fifth limb, an essential gait at slower speeds as slow hopping is energetically unfeasible. Analysis of limb bone measurements of sthenurines in comparison with extant macropodoids shows a number of anatomical differences, especially in the large species. The scaling of long bone robusticity indicates that sthenurines are following the "normal" allometric trend for macropodoids, while the large extant kangaroos are relatively gracile. Other morphological differences are indicative of adaptations for a novel type of locomotor behavior in sthenurines: they lacked many specialized features for rapid hopping, and they also had anatomy indicative of supporting their body with an upright trunk (e.g., dorsally tipped ischiae, and of supporting their weight on one leg at a time (e.g., larger hips and knees, stabilized ankle joint. We propose that sthenurines adopted a bipedal striding gait (a gait occasionally observed in extant tree-kangaroos: in the smaller and earlier forms, this gait may have been employed as an alternative to pentapedal locomotion at slower speeds, while in the larger Pleistocene forms this gait may have enabled them to evolve to body sizes where hopping

  3. Locomotion in extinct giant kangaroos: were sthenurines hop-less monsters?

    Science.gov (United States)

    Janis, Christine M; Buttrill, Karalyn; Figueirido, Borja

    2014-01-01

    Sthenurine kangaroos (Marsupialia, Diprotodontia, Macropodoidea) were an extinct subfamily within the family Macropodidae (kangaroos and rat-kangaroos). These "short-faced browsers" first appeared in the middle Miocene, and radiated in the Plio-Pleistocene into a diversity of mostly large-bodied forms, more robust than extant forms in their build. The largest (Procoptodon goliah) had an estimated body mass of 240 kg, almost three times the size of the largest living kangaroos, and there is speculation whether a kangaroo of this size would be biomechanically capable of hopping locomotion. Previously described aspects of sthenurine anatomy (specialized forelimbs, rigid lumbar spine) would limit their ability to perform the characteristic kangaroo pentapedal walking (using the tail as a fifth limb), an essential gait at slower speeds as slow hopping is energetically unfeasible. Analysis of limb bone measurements of sthenurines in comparison with extant macropodoids shows a number of anatomical differences, especially in the large species. The scaling of long bone robusticity indicates that sthenurines are following the "normal" allometric trend for macropodoids, while the large extant kangaroos are relatively gracile. Other morphological differences are indicative of adaptations for a novel type of locomotor behavior in sthenurines: they lacked many specialized features for rapid hopping, and they also had anatomy indicative of supporting their body with an upright trunk (e.g., dorsally tipped ischiae), and of supporting their weight on one leg at a time (e.g., larger hips and knees, stabilized ankle joint). We propose that sthenurines adopted a bipedal striding gait (a gait occasionally observed in extant tree-kangaroos): in the smaller and earlier forms, this gait may have been employed as an alternative to pentapedal locomotion at slower speeds, while in the larger Pleistocene forms this gait may have enabled them to evolve to body sizes where hopping was no longer

  4. A novel approach to mechanical foot stimulation during human locomotion under body weight support.

    Science.gov (United States)

    Gravano, S; Ivanenko, Y P; Maccioni, G; Macellari, V; Poppele, R E; Lacquaniti, F

    2011-04-01

    Input from the foot plays an essential part in perceiving support surfaces and determining kinematic events in human walking. To simulate adequate tactile pressure inputs under body weight support (BWS) conditions that represent an effective form of locomotion training, we here developed a new method of phasic mechanical foot stimulation using light-weight pneumatic insoles placed inside the shoes (under the heel and metatarsus). To test the system, we asked healthy participants to walk on a treadmill with different levels of BWS. The pressure under the stimulated areas of the feet and subjective sensations were higher at high levels of BWS and when applied to the ball and toes rather than heels. Foot stimulation did not disturb significantly the normal motor pattern, and in all participants we evoked a reliable step-synchronized triggering of stimuli for each leg separately. This approach has been performed in a general framework looking for "afferent templates" of human locomotion that could be used for functional sensory stimulation. The proposed technique can be used to imitate or partially restore surrogate contact forces under body weight support conditions. Copyright © 2010 Elsevier B.V. All rights reserved.

  5. Stable beams

    CERN Multimedia

    2015-01-01

    Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure.   I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...

  6. [Etiological diagnosis of leg ulcers].

    Science.gov (United States)

    Debure, Clélia

    2010-09-20

    Etiological diagnosis of leg ulcers must be the first step of treatment, even if we know that veinous disease is often present. We can build a clinical decisional diagram, which helps us to understand and not forget the other causes of chronic wounds and choose some basic examination, like ultrasound and histological findings. This diagnosis helps to choose the right treatment in order to cure even the oldest venous ulcers. Educational programs should be improved to prevent recurrence.

  7. Thick legs - not always lipedema.

    Science.gov (United States)

    Reich-Schupke, Stefanie; Altmeyer, Peter; Stücker, Markus

    2013-03-01

    Due to its increased presence in the press and on television, the diagnosis of lipedema is on the way to becoming a trendy diagnosis for those with thick legs. Despite this, one must recognize that lipedema is a very rare disease. It is characterized by disproportional obesity of the extremities, especially in the region of the hip and the legs, hematoma development after minimal trauma, and increased pressure-induced or spontaneous pain. Aids for making the correct diagnosis are (duplex) sonography, the waist-hip index or the waist-height index and lymphoscintigraphy. Important differential diagnoses are constitutional variability of the legs, lipohypertrophy in obesity, edema in immobility, edema in chronic venous insufficiency and rheumatic diseases. The symptom-based therapy of lipedema consists of conservative (compression, manual lymphatic drainage, exercise) and surgical treatments (liposuction). Until now there is no curative therapy. Obesity is an important risk factor for the severity and prognosis of lipedema. Further studies for a better understanding of the pathogenesis of lipedema and in the end possible curative treatments are urgently needed. © The Authors | Journal compilation © Blackwell Verlag GmbH, Berlin.

  8. Guiding locomotion in complex dynamic environments

    Directory of Open Access Journals (Sweden)

    Brett R Fajen

    2013-07-01

    Full Text Available Locomotion in complex dynamic environments is an integral part of many daily activities, including walking in crowded spaces, driving on busy roadways, and playing sports. Many of the tasks that humans perform in such environments involve interactions with moving objects -- that is, they require people to coordinate their own movement with the movements of other objects. A widely adopted framework for research on the detection, avoidance, and interception of moving objects is the bearing angle model, according to which observers move so as to keep the bearing angle of the object constant for interception and varying for obstacle avoidance. The bearing angle model offers a simple, parsimonious account of visual control but has several significant limitations and does not easily scale up to more complex tasks. In this paper, I introduce an alternative account of how humans choose actions and guide locomotion in the presence of moving objects. I show how the new approach addresses the limitations of the bearing angle model and accounts for a variety of behaviors involving moving objects, including (1 choosing whether to pass in front of or behind a moving obstacle, (2 perceiving whether a gap between a pair of moving obstacles is passable, (3 avoiding a collision while passing through single or multiple lanes of traffic, (4 coordinating speed and direction of locomotion during interception, (5 simultaneously intercepting a moving target while avoiding a stationary or moving obstacle, and (6 knowing whether to abandon the chase of a moving target. I also summarize data from recent studies that support the new approach.

  9. A survey report for the biped locomotion model under external force

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Ichiro; Takanishi, Atsuo [Waseda Univ., Tokyo (Japan); Kume, Etsuo

    1993-10-01

    A mechanical design study of biped locomotion robots is being performed at JAERI within the scope of the Human Acts Simulation Program (HASP). The design study at JAERI is of an arbitrarily mobile robot for inspection of nuclear facilities. We have developed the simulation software which has capability of obtaining several types of stable motions for straight walking in terms of design tools. In addition, we are studying more complex walking patterns such as turning. However, in order to realize the robustness of walking, it is also necessary for the robot to have a capability of walking under external force as a disturbance which is caused by touching an object and so on. A survey has been performed for collecting useful information from already existing biped locomotion robots. This is a survey report for the biped locomotion model under external force: the WL-12RIII/IV designed and developed at Waseda University. This report includes the machine model, control system, control method and results of walking experiments. (author).

  10. Serpentine Locomotion Articulated Chain: ANA II

    Directory of Open Access Journals (Sweden)

    A. M. Cardona

    2005-01-01

    Full Text Available When humanity faces challenges in solving problems beyond their technical resources, and has no foundation to solve a problem, engineering must search for an answer developing new concepts and innovative frameworks to excel these limitations and travel beyond our capabilities. This project “Serpentine locomotion articulated chain: ANA II” is a self-contained robot built to evaluate the behavior of the platform being capable of serpentine movements, in a modular chain mechanical design, based on a master/slave architecture.

  11. Viscous streaming for locomotion and transport

    Science.gov (United States)

    Gazzola, Mattia; Parthasarathy, Tejaswin

    2017-11-01

    Rectified and oscillatory flows associated with vibrating boundaries have been employed in a variety of tasks, especially in microfluidics. The associated fluid mechanics is well known in the case of simple geometries, cylinders in particular, yet little is known in the case of active, complex systems. Motivated by potential applications in swimming mini-bots, we established an accurate and robust computational framework to investigate the flow behavior associated with oscillations of multiple and deforming shapes with an emphasis on streaming assisted locomotion and transport systems.

  12. Intraspecific variation in aerobic and anaerobic locomotion

    DEFF Research Database (Denmark)

    Svendsen, Jon Christian; Tirsgård, Bjørn; Cordero, Gerardo A.

    2015-01-01

    Intraspecific variation and trade-off in aerobic and anaerobic traits remain poorly understood in aquatic locomotion. Using gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata), both axial swimmers, this study tested four hypotheses: (1) gait transition from steady...... to unsteady (i.e., burst-assisted) swimming is associated with anaerobic metabolism evidenced as excess post exercise oxygen consumption (EPOC); (2) variation in swimming performance (critical swimming speed; U crit) correlates with metabolic scope (MS) or anaerobic capacity (i.e., maximum EPOC); (3...

  13. Design of Spiking Central Pattern Generators for Multiple Locomotion Gaits in Hexapod Robots by Christiansen Grammar Evolution.

    Science.gov (United States)

    Espinal, Andres; Rostro-Gonzalez, Horacio; Carpio, Martin; Guerra-Hernandez, Erick I; Ornelas-Rodriguez, Manuel; Sotelo-Figueroa, Marco

    2016-01-01

    This paper presents a method to design Spiking Central Pattern Generators (SCPGs) to achieve locomotion at different frequencies on legged robots. It is validated through embedding its designs into a Field-Programmable Gate Array (FPGA) and implemented on a real hexapod robot. The SCPGs are automatically designed by means of a Christiansen Grammar Evolution (CGE)-based methodology. The CGE performs a solution for the configuration (synaptic weights and connections) for each neuron in the SCPG. This is carried out through the indirect representation of candidate solutions that evolve to replicate a specific spike train according to a locomotion pattern (gait) by measuring the similarity between the spike trains and the SPIKE distance to lead the search to a correct configuration. By using this evolutionary approach, several SCPG design specifications can be explicitly added into the SPIKE distance-based fitness function, such as looking for Spiking Neural Networks (SNNs) with minimal connectivity or a Central Pattern Generator (CPG) able to generate different locomotion gaits only by changing the initial input stimuli. The SCPG designs have been successfully implemented on a Spartan 6 FPGA board and a real time validation on a 12 Degrees Of Freedom (DOFs) hexapod robot is presented.

  14. Gas chromatographic and electron spin resonance investigations of gamma-irradiated frog legs

    International Nuclear Information System (INIS)

    Morehouse, K.M.; Ku, Yuoh; Albrecht, H.L.; Yang, G.C.

    1991-01-01

    Several very sensitive techniques to measure radiation-induced products in frog legs were investigated. Presented here are results from the use of electron spin resonance (ESR) spectroscopy and capillary gas chromatography (GC) to measure radiolysis products in γ-irradiated frog legs. When bone is irradiated, a characteristic ESR signal develops and is easily measured. The intensity of the ESR signal is dose-dependent and stable for several months at room temperature. When triglycerides or fatty acids are irradiated, some of the major stable products formed are hydrocarbons with one less carbon than the precursor fatty acids. These hydrocarbons are formed as the result of the loss of CO 2 during various free radical reactions. A capillary GC procedure was developed to monitor the formation of these hydrocarbons in γ-irradiated frog legs. Since frog legs contain large amounts of palmitic, stearic, oleic, and linoleic acids, the formation of the hydrocarbons (pentadecane, heptadecane, 8-heptadecene, and 6,9-heptadecadiene, respectively) from the decarboxylation of these fatty acids was monitored. The yields of these hydrocarbons were found to be linear with applied dose. A sample from a lot of imported frog legs that were believed to have been treated with ionizing radiation was also analyzed. The ESR technique, in conjunction with the GC data on the hydrocarbons, appears to be a useful approach for identifying and monitoring frog legs that have been treated with ionizing radiation. (author)

  15. Locomotion Induces Stimulus-Specific Response Enhancement in Adult Visual Cortex.

    Science.gov (United States)

    Kaneko, Megumi; Fu, Yu; Stryker, Michael P

    2017-03-29

    The responses of neurons in the visual cortex (V1) of adult mammals have long been thought to be stable over long periods. Here, we investigated whether repeated exposure to specific stimuli would enhance V1 visual responses in mice using intrinsic signal imaging through the intact skull and two-photon imaging of calcium signals in single neurons. Mice ran on Styrofoam balls floating on air while viewing one of three different, high-contrast visual stimuli. V1 responses to the stimuli that were viewed by the animal were specifically enhanced, while responses to other stimuli were unaffected. Similar exposure in stationary mice or in mice in which NMDA receptors were partially blocked did not significantly enhance responses. These findings indicate that stimulus-specific plasticity in the adult visual cortex depends on concurrent locomotion, presumably as a result of the high-gain state of the visual cortex induced by locomotion. SIGNIFICANCE STATEMENT We report a rapid and persistent increase in visual cortical responses to visual stimuli presented during locomotion in intact mice. We first used a method that is completely noninvasive to image intrinsic signals through the intact skull. We then measured the same effects on single neurons using two-photon calcium imaging and found that the increase in response to a particular stimulus produced by locomotion depends on how well the neuron is initially driven by the stimulus. To our knowledge, this is the first time such enhancement has been described in single neurons or using noninvasive measurements. Copyright © 2017 the authors 0270-6474/17/373532-12$15.00/0.

  16. Combining Bio-inspired Sensing with Bio-inspired Locomotion

    DEFF Research Database (Denmark)

    Shaikh, Danish; Hallam, John; Christensen-Dalsgaard, Jakob

    In this paper we present a preliminary Braitenberg vehicle–like approach to combine bio-inspired audition with bio-inspired quadruped locomotion in simulation. Locomotion gaits of the salamander–like robot Salamandra robotica are modified by a lizard’s peripheral auditory system model...

  17. The Determination of the Asynchronous Traction Motor Characteristics of Locomotive

    Directory of Open Access Journals (Sweden)

    Pavel Grigorievich Kolpakhchyan

    2017-01-01

    Full Text Available The article deals with the problem of the locomotive asynchronous traction motor control with the AC diesel-electric transmission. The limitations of the torque of the traction motor when powered by the inverter are determined. The recommendations to improve the use of asynchronous traction motor of locomotives with the AC diesel-electric transmission are given.

  18. 49 CFR 232.105 - General requirements for locomotives.

    Science.gov (United States)

    2010-10-01

    ... locomotives. (a) The air brake equipment on a locomotive shall be in safe and suitable condition for service... set pressure at any service application with the brakes control valve in the freight position. If such... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRAKE SYSTEM SAFETY STANDARDS FOR FREIGHT AND OTHER NON-PASSENGER...

  19. Locomotive emissions measurements for various blends of biodiesel fuel.

    Science.gov (United States)

    2014-12-01

    The objective of this project was to assess the effects of various blends of biodiesel on locomotive engine exhaust emissions. The : emission tests were conducted on two locomotive models, a Tier 2 EMD SD70ACe and a Tier 1 Plus GE Dash9-44CW, using t...

  20. THE DYNAMICS AND TRACTION ENERGY METRICS LOCOMOTIVE VL40

    Directory of Open Access Journals (Sweden)

    S. V. Pylypenko

    2008-03-01

    Full Text Available In the article the results of dynamic running and traction-energy tests of the electric locomotive VL40U are presented. In accordance with the test results a conclusion about the suitability of electric locomotive of such a type for operation with trains containing up to 15 passenger coaches inclusive is made.

  1. Architectures of soft robotic locomotion enabled by simple mechanical principles.

    Science.gov (United States)

    Zhu, Liangliang; Cao, Yunteng; Liu, Yilun; Yang, Zhe; Chen, Xi

    2017-06-28

    In nature, a variety of limbless locomotion patterns flourish, from the small or basic life forms (Escherichia coli, amoebae, etc.) to the large or intelligent creatures (e.g., slugs, starfishes, earthworms, octopuses, jellyfishes, and snakes). Many bioinspired soft robots based on locomotion have been developed in the past few decades. In this work, based on the kinematics and dynamics of two representative locomotion modes (i.e., worm-like crawling and snake-like slithering), we propose a broad set of innovative designs for soft mobile robots through simple mechanical principles. Inspired by and going beyond the existing biological systems, these designs include 1-D (dimensional), 2-D, and 3-D robotic locomotion patterns enabled by the simple actuation of continuous beams. We report herein over 20 locomotion modes achieving various locomotion functions, including crawling, rising, running, creeping, squirming, slithering, swimming, jumping, turning, turning over, helix rolling, wheeling, etc. Some are able to reach high speed, high efficiency, and overcome obstacles. All these locomotion strategies and functions can be integrated into a simple beam model. The proposed simple and robust models are adaptive for severe and complex environments. These elegant designs for diverse robotic locomotion patterns are expected to underpin future deployments of soft robots and to inspire a series of advanced designs.

  2. Locomotion With Loads: Practical Techniques for Predicting Performance Outcomes

    Science.gov (United States)

    2015-05-01

    COVERED 15Apr2014 - 14Apr2015 4. TITLE AND SUBTITLE Locomotion With Loads: Practical Techniques for Predicting Performance Outcomes 5a. CONTRACT...al., 1982; Kram & Taylor, 1990) that the mass- specific metabolic cost of locomotion varies in a systematic manner with the linear dimensions of the

  3. Locomotion Induced by Spatial Restriction in Adult Drosophila.

    Science.gov (United States)

    Xiao, Chengfeng; Robertson, R Meldrum

    2015-01-01

    Drosophila adults display an unwillingness to enter confined spaces but the behaviors induced by spatial restriction in Drosophila are largely unknown. We developed a protocol for high-throughput analysis of locomotion and characterized features of locomotion in a restricted space. We observed intense and persistent locomotion of flies in small circular arenas (diameter 1.27 cm), whereas locomotion was greatly reduced in large circular arenas (diameter 3.81 cm). The increased locomotion induced by spatial restriction was seen in male flies but not female flies, indicating sexual dimorphism of the response to spatial restriction. In large arenas, male flies increased locomotion in arenas previously occupied by male but not female individuals. In small arenas, such pre-conditioning had no effect on male flies, which showed intense and persistent locomotion similar to that seen in fresh arenas. During locomotion with spatial restriction, wildtype Canton-S males traveled slower and with less variation in speed than the mutant w1118 carrying a null allele of white gene. In addition, wildtype flies showed a stronger preference for the boundary than the mutant in small arenas. Genetic analysis with a series of crosses revealed that the white gene was not associated with the phenotype of boundary preference in wildtype flies.

  4. Coordination of locomotion with voluntary movements in humans

    NARCIS (Netherlands)

    Ivanenko, Yuri P; Cappellini, Germana; Dominici, Nadia; Poppele, Richard E; Lacquaniti, Francesco

    2005-01-01

    Muscle activity occurring during human locomotion can be accounted for by five basic temporal activation patterns in a variety of locomotion conditions. Here, we examined how these activation patterns interact with muscle activity required for a voluntary movement. Subjects produced a voluntary

  5. Ciliary Locomotion in Varying Viscosity Flow

    Science.gov (United States)

    Eastham, Patrick; Shoele, Kourosh

    2017-11-01

    Ciliary locomotion is a common method of transportation employed by bacteria. They must be able to move through their environment at will to seek nutrients as well as avoid dangers. While research into bacteria motility has received considerable attention, very little has been done to consider the effects of a spatially-varying viscosity environment on swimming. This presentation will discuss recent research into how bacteria can take advantage of nutrient-dependent viscosity to generate an asymmetric stress field around their body, potentially increasing free-swimming velocity. First, we analytically show that asymptotically small variations in viscosity due to nutrient concentrations can affect the free-swimming velocity of a bacteria. Then we extend our study to fully nonlinear coupling between nutrient concentration and viscosity and employ the Finite Element method to solve a system containing a convection-diffusion equation for nutrient concentration as well as Stokes flow for stress distribution on the swimmer. We will discuss how the free-swimming velocity profile changes for various nutrient Pecletnumbers and ciliary locomotion modes.

  6. Environmental engineering simplifies subterranean locomotion control

    Science.gov (United States)

    Gravish, Nick; Monaenkova, Darya; Goodisman, Michael A. D.; Goldman, Daniel I.

    2013-03-01

    We hypothesize that ants engineer habitats which reduce locomotion control requirements. We studied tunnel construction, and locomotion, in fire ants (Solenopsis invicta, body length L = 0 . 35 +/- 0 . 05). In their daily life, ants forage for food above ground and return resources to the nest. This steady-state tunnel traffic enables high-throughput biomechanics studies of tunnel climbing. In a laboratory experiment we challenged fire ants to climb through 8 cm long glass tunnels (D = 0.1 - 0.9 cm) that separated a nest from an open arena with food and water. During ascending and descending climbs we induced falls by a motion-activated rapid, short, downward translation of the tunnels. Normalized tunnel diameter (D / L) determined the ability of ants to rapidly recover from perturbations. Fall arrest probability was unity for small D / L , and zero for large D / L . The transition from successful to unsuccessful arrest occurred at D / L = 1 . 4 +/- 0 . 3 . Through X-Ray computed tomography study we show that the diameter of ant-excavated tunnels is independent of soil-moisture content (studied from 1-20%) and particle size (50-595 μm diameter), and has a mean value of D / L = 1 . 06 +/- 0 . 23 . Thus fire ants construct tunnels of diameter near the onset of fall instability.

  7. Reversibility in locomotion in granular media

    Science.gov (United States)

    Savoie, William; Goldman, Daniel

    2013-11-01

    A recent study of a self-deforming robot [Hatton et al., PRL, 2013] demonstrated that slow movement in dry granular media resembles locomotion in low Re fluids, in part because inertia is dominated by friction. The study indicated that granular swimming was kinematically reversible, a surprise because yielding in granular flow is irreversible. To investigate if reciprocal motions lead to net displacements in granular swimmers, in laboratory experiments, we study the locomotion of a robotic ``scallop'' consisting of a square body with two flipper-like limbs controlled to flap forward and backward symmetrically (a flap cycle). The body is constrained by linear bearings to allow motion in only one dimension. We vary the the flapping frequency f, the body/flipper burial depth d, and the number of flaps N in a deep bed of 6 mm diameter plastic spheres. Over a range of f and d, the N = 1 cycle produces net translation of the body; however for large N, a cycle produces no net translation. We conclude that symmetric strokes in granular swimming are irreversible at the onset of self-deformation, but become asymptotically reversible. work supported by NSF and ARL.

  8. Different forms of locomotion in the spinal lamprey.

    Science.gov (United States)

    Hsu, Li-Ju; Orlovsky, Grigori N; Zelenin, Pavel V

    2014-06-01

    Forward locomotion has been extensively studied in different vertebrate animals, and the principal role of spinal mechanisms in the generation of this form of locomotion has been demonstrated. Vertebrate animals, however, are capable of other forms of locomotion, such as backward walking and swimming, sideward walking, and crawling. Do the spinal mechanisms play a principal role in the generation of these forms of locomotion? We addressed this question in lampreys, which are capable of five different forms of locomotion - fast forward swimming, slow forward swimming, backward swimming, forward crawling, and backward crawling. To induce locomotion in lampreys spinalised at the second gill level, we used either electrical stimulation of the spinal cord at different rostrocaudal levels, or tactile stimulation of specific cutaneous receptive fields from which a given form of locomotion could be evoked in intact lampreys. We found that any of the five forms of locomotion could be evoked in the spinal lamprey by electrical stimulation of the spinal cord, and some of them by tactile stimulation. These results suggest that spinal mechanisms in the lamprey, in the absence of phasic supraspinal commands, are capable of generating the basic pattern for all five forms of locomotion observed in intact lampreys. In spinal lampreys, the direction of swimming did not depend on the site of spinal cord stimulation, but on the stimulation strength. The direction of crawling strongly depended on the body configuration. The spinal structures presumably activated by spinal cord stimulation and causing different forms of locomotion are discussed. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  9. Epilepsy and restless legs syndrome.

    Science.gov (United States)

    Geyer, James D; Geyer, Emery E; Fetterman, Zachary; Carney, Paul R

    2017-03-01

    Restless legs syndrome (RLS) is a common neurological movement disorder occurring in approximately 10% of the general population. The prevalence of moderately severe RLS is 2.7% overall (3.7% for women and 1.7% for men). Epilepsy is also a common neurological disorder with significant associated morbidity and impact on quality of life. We evaluated the severity and frequency of primary RLS in patients with localization-related temporal lobe epilepsy (TLE) and investigated the role of prodromal RLS symptoms as a warning sign and lateralizing indicator. All epilepsy patients seen in the outpatient clinic were screened for movement disorders from 2005 to 2015. Ninety-eight consecutive patients with localization-related TLE (50 right TLE and 48 left TLE) who met inclusion criteria were seen in the outpatient clinic. The control group consisted of 50 individuals with no history or immediate family history of epilepsy. Each patient was evaluated with the International Restless Legs Study Group (IRLSSG) questionnaire, NIH RLS diagnostic criteria, ferritin level, and comprehensive sleep screening including polysomnography. Furthermore, patients with obstructive sleep apnea or a definite cause of secondary restless legs syndrome such as low serum ferritin or serum iron levels were also excluded from the study. There was a significant association between the type of epilepsy and whether or not patients had RLS χ 2 (1)=10.17, prestlessness was typically described as moderately severe. The RLS symptoms were more common and somewhat more severe in the right TLE group than the left TLE group. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. 40 CFR 1033.515 - Discrete-mode steady-state emission tests of locomotives and locomotive engines.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Discrete-mode steady-state emission... Procedures § 1033.515 Discrete-mode steady-state emission tests of locomotives and locomotive engines. This... a warm-up followed by a sequence of nominally steady-state discrete test modes, as described in...

  11. Kinematics Analysis of Two Parallel Locomotion Mechanisms

    Science.gov (United States)

    2010-08-27

    1998, "Design Considerations of New Six Degrees-of-Freedom Parallel Robots," Leuven, Belgium, 2, pp. 1327-1333. [19] Angeles, J., Guilin , Y., and...Parallel Manipulators: Identification and Elimination," Minneapolis, MN, USA, 72, pp. 459-466. [25] Dash, A. K., Chen, I. M., Song Huat, Y., and Guilin ...28] Guilin , Y., Chen, I. M., Wei, L., and Angeles, J., 2001, "Singularity Analysis of Three-Legged Parallel Robots Based on Passive-Joint Velocities

  12. Quinine for Nocturnal Leg Cramps

    Science.gov (United States)

    Man-Son-Hing, Malcolm; Wells, George; Lau, Anita

    1998-01-01

    OBJECTIVE With respect to the use of quinine for the treatment of nocturnal leg cramps, to determine whether the findings of a previously performed meta-analysis of published data are altered with the addition of unpublished data, and whether publication bias is present in this area. DESIGN A meta-analysis of eight (four published and four unpublished) randomized, double-blind, placebo-controlled trials, seven of which had a crossover design. SETTING Randomized trials that were available as of July 1997. SUBJECTS Ambulatory patients (659) who suffered from regular nocturnal leg cramps. MAIN RESULTS When individual patient data from all crossover studies were pooled, persons had 3.60 (95% confidence interval [CI] 2.15, 5.05) fewer cramps in a 4-week period when taking quinine compared with placebo. This compared with an estimate of 8.83 fewer cramps (95% CI 4.16, 13.49) from pooling published studies alone. The corresponding relative risk reductions were 21% (95% CI 12%, 30%) and 43% (95% CI 21%, 65%), respectively. Compared with placebo, the use of quinine was associated with an increased incidence of side effects, particularly tinnitus. Publication bias is present in the reporting of the efficacy of quinine for this indication, as almost all published studies reported larger estimates of its efficacy than did unpublished studies. CONCLUSIONS This study confirms that quinine is efficacious in the prevention of nocturnal leg cramps. However, its benefit may not be as large as reported from the pooling of published studies alone. Given the side effect profile of quinine, nonpharmacologic therapy (e.g., regular passive stretching of the affected muscle) is the best first-line treatment. For persons who find this ineffective and whose quality of life is significantly affected, a trial of quinine is warranted. Prescribing physicians must closely monitor the risks and benefits in individual patients. Publication bias is present in this area even though there is

  13. Leg fluid accumulation during prolonged sitting.

    Science.gov (United States)

    Vena, Daniel; Rubianto, Jonathan; Popovic, Milos; Yadollahi, Azadeh

    2016-08-01

    The accumulation of fluid in the legs due to sedentariness can be a health risk in extreme cases. Negative health impacts associated with leg fluid accumulation include leg edema and risk of blood clots. Furthermore, fluid accumulating in the legs is accompanied by fluid shift into the upper body which is also associated with health risks such as: increased blood pressure when lying down, respiratory problems in people with heart failure, and increased sleep apnea. Understanding the pattern by which fluid accumulates in the legs can aid in the development of devices for reducing leg fluid accumulation. The purpose of this study was to characterize the time course of fluid accumulation over a two-and-half-hour seated period. Non-obese participants with sleep apnea and no other co-morbidities were included in the sample as part of a larger study. Leg fluid was measured continuously using a method of bioelectrical impedance. Participants were first asked to lie supine for 30 minutes as a washout, and then sat with their legs still for two and a half hours. The main finding of this study is that the pattern of leg fluid accumulation differed in the first 45 minutes compared to the latter 105 minutes. In the first 45 minutes, fluid accumulated according to first order exponential function. In the latter period, fluid accumulated according to a linear function. The initial exponential accumulation is likely due to the large increase in capillary pressure caused by rapid blood flow into the legs due to gravity, leading to substantial filtration of blood plasma into the tissue spaces. The latter linear portion likely represents continued slow filtration of fluid out of the vasculature and into the tissue spaces. This is the first study to show that fluid accumulation in the legs is a combination of an exponential and linear functions. The linear increase identifies that there is no foreseeable point in which leg fluid stops accumulating while sitting for prolonged periods.

  14. Control strategy for energy-efficient bipedal walking with variable leg stiffness

    NARCIS (Netherlands)

    Visser, L.C.; Stramigioli, Stefano; Carloni, Raffaella

    In this work, we propose a hybrid model for a bipedal walker with controlled variable leg stiffness, and a control strategy for stable gait control. The control reference is a passive gait of the limit-case bipedal spring-loaded inverted pendulum model with massless feet, ensuring that the gait is

  15. Running with a load increases leg stiffness.

    Science.gov (United States)

    Silder, Amy; Besier, Thor; Delp, Scott L

    2015-04-13

    Spring-mass models have been used to characterize running mechanics and leg stiffness in a variety of conditions, yet it remains unknown how running while carrying a load affects running mechanics and leg stiffness. The purpose of this study was to test the hypothesis that running with a load increases leg stiffness. Twenty-seven subjects ran at a constant speed on a force-measuring treadmill while carrying no load, and while wearing weight vests loaded with 10%, 20%, and 30% of body weight. We measured lower extremity motion and created a scaled musculoskeletal model of each subject, which we used to estimate lower extremity joint angles and leg length. We estimated dimensionless leg stiffness as the ratio of the peak vertical ground reaction force (normalized to body weight) and the change in stance phase leg length (normalized to leg length at initial foot contact). Leg length was calculated as the distance from the center of the pelvis to the center-of-pressure under the foot. We found that dimensionless leg stiffness increased when running with load (p=0.001); this resulted from an increase in the peak vertical ground reaction force (pleg length (p=0.025). When running with load, subjects had longer ground contact times (pleg stiffness to accommodate an added load. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Modelling gait transition in two-legged animals

    Science.gov (United States)

    Pinto, Carla M. A.; Santos, Alexandra P.

    2011-12-01

    The study of locomotor patterns has been a major research goal in the last decades. Understanding how intralimb and interlimb coordination works out so well in animals' locomotion is a hard and challenging task. Many models have been proposed to model animal's rhythms. These models have also been applied to the control of rhythmic movements of adaptive legged robots, namely biped, quadruped and other designs. In this paper we study gait transition in a central pattern generator (CPG) model for bipeds, the 4-cells model. This model is proposed by Golubitsky, Stewart, Buono and Collins and is studied further by Pinto and Golubitsky. We briefly resume the work done by Pinto and Golubitsky. We compute numerically gait transition in the 4-cells CPG model for bipeds. We use Morris-Lecar equations and Wilson-Cowan equations as the internal dynamics for each cell. We also consider two types of coupling between the cells: diffusive and synaptic. We obtain secondary gaits by bifurcation of primary gaits, by varying the coupling strengths. Nevertheless, some bifurcating branches could not be obtained, emphasizing the fact that despite analytically those bifurcations exist, finding them is a hard task and requires variation of other parameters of the equations. We note that the type of coupling did not influence the results.

  17. Restless legs syndrome and periodic leg movements in patients with movement disorders: Specific considerations.

    Science.gov (United States)

    Högl, Birgit; Stefani, Ambra

    2017-05-01

    Restless legs syndrome is a frequent neurological disorder with potentially serious and highly distressing treatment complications. The role and potential implications of periodic leg movements during sleep range from being a genetic risk marker for restless legs syndrome to being a cardiovascular risk factor. The diagnosis of restless legs syndrome in patients with daytime movement disorders is challenging and restless legs syndrome needs to be differentiated from other sleep-related movement disorders. This article provides an update on the diagnosis of restless legs syndrome as an independent disorder and the role of periodic leg movements and reviews the association of restless legs syndrome with Parkinson's disease and other movement disorders. © 2017 International Parkinson and Movement Disorder Society. © 2017 International Parkinson and Movement Disorder Society.

  18. Fish Locomotion: Recent Advances and New Directions

    Science.gov (United States)

    Lauder, George V.

    2015-01-01

    Research on fish locomotion has expanded greatly in recent years as new approaches have been brought to bear on a classical field of study. Detailed analyses of patterns of body and fin motion and the effects of these movements on water flow patterns have helped scientists understand the causes and effects of hydrodynamic patterns produced by swimming fish. Recent developments include the study of the center-of-mass motion of swimming fish and the use of volumetric imaging systems that allow three-dimensional instantaneous snapshots of wake flow patterns. The large numbers of swimming fish in the oceans and the vorticity present in fin and body wakes support the hypothesis that fish contribute significantly to the mixing of ocean waters. New developments in fish robotics have enhanced understanding of the physical principles underlying aquatic propulsion and allowed intriguing biological features, such as the structure of shark skin, to be studied in detail.

  19. Slipping slender bodies and enhanced flagellar locomotion

    Science.gov (United States)

    Man, Yi; Lauga, Eric

    2017-11-01

    In the biological world, many cells exploit slender appendages to swim, include numerous species of bacteria, algae and spermatozoa. A classical method to describe the flow field around such appendages is slender-body theory (SBT), which is often used to study flagellar motility in Newtonian fluids. However, biology environments are often rheologically complex due to the presence of polymers. These polymers generically phase-separate near rigid boundaries where low-viscosity fluid layers lead to effective slip on the surface. In this talk, we present an analytical derivation of SBT in the case where the no-slip boundary condition on the appendage is replaced by a Navier slip boundary condition. Our results demonstrate in particular a systematic reduction of the resistance coefficient of the slender filaments in their tangential direction, which leads to enhanced flagellar locomotion.

  20. Coupling of cytoskeleton functions for fibroblast locomotion

    DEFF Research Database (Denmark)

    Couchman, J R; Lenn, M; Rees, D A

    1985-01-01

    the cells to lose control of shape and organelle distribution even though forward protrusion continued unaffected. Cytoplasmic displacements shown by marker mitochondria correlated with adjacent fluctuations at the leading edge, and drug treatments which increased the amplitude of mitochondrial movements...... caused visible protrusions in projected positions at the leading edge. We conclude that fibroblast locomotion may be driven coordinately by a common set of motility mechanisms and that this coordination may be lost as a result of physical or pharmacological disturbance. Taking our evidence with results...... from other Laboratories, we propose the following cytoskeleton functions. (i) Protrusive activity, probably based on solation--gelation cycles of the actin based cytoskeleton and membrane recycling which provides cellular and membrane components for streaming through the cell body to the leading edge...

  1. Collective locomotion of non-swimmers

    Science.gov (United States)

    Lauga, Eric; Bartolo, Denis

    2009-03-01

    To achieve propulsion at low Reynolds number, a swimmer (e.g. a biological cell such as a bacterium, or a spermatozoon) must deform its shape in time in a way that is not invariant under time-reversal symmetry (non-reciprocal); this is Purcell's scallop theorem. We show here explicitly that there is no many-scallop theorem. Two active bodies undergoing reciprocal deformations - and therefore incapable of swimming when considered separately - can exploit hydrodynamic interaction to swim. If the bodies are polar, we also show that they experience effective long-range interactions. We derive our results analytically for a minimal dimers model, and generalize them to more complex geometries on the basis of symmetry and scaling arguments. Furthermore, we explain how such cooperative locomotion can be realized experimentally by shaking a collection of soft particles with a homogeneous external field, thereby making non-swimmers swim.

  2. Soft Snakes: Construction, Locomotion, and Control

    Science.gov (United States)

    Branyan, Callie; Courier, Taylor; Fleming, Chloe; Remaley, Jacquelin; Hatton, Ross; Menguc, Yigit

    We fabricated modular bidirectional silicone pneumatic actuators to build a soft snake robot, applying geometric models of serpenoid swimmers to identify theoretically optimal gaits to realize serpentine locomotion. With the introduction of magnetic connections and elliptical cross-sections in fiber-reinforced modules, we can vary the number of continuum segments in the snake body to achieve more supple serpentine motion in a granular media. The performance of these gaits is observed using a motion capture system and efficiency is assessed in terms of pressure input and net displacement. These gaits are optimized using our geometric soap-bubble method of gait optimization, demonstrating the applicability of this tool to soft robot control and coordination.

  3. Locomotion Efficiency Optimization of Biologically Inspired Snake Robots

    Directory of Open Access Journals (Sweden)

    Eleni Kelasidi

    2018-01-01

    Full Text Available Snake robots constitute bio-inspired solutions that have been studied due to their ability to move in challenging environments where other types of robots, such as wheeled or legged robots, usually fail. In this paper, we consider both land-based and swimming snake robots. One of the principal concerns of the bio-inspired snake robots is to increase the motion efficiency in terms of the forward speed by improving the locomotion methods. Furthermore, energy efficiency becomes a crucial challenge for this type of robots due to the importance of long-term autonomy of these systems. In this paper, we take into account both the minimization of the power consumption and the maximization of the achieved forward velocity in order to investigate the optimal gait parameters for bio-inspired snake robots using lateral undulation and eel-like motion patterns. We furthermore consider possible negative work effects in the calculation of average power consumption of underwater snake robots. To solve the multi-objective optimization problem, we propose transforming the two objective functions into a single one using a weighted-sum method. For different set of weight factors, Particle Swarm Optimization is applied and a set of optimal points is consequently obtained. Pareto fronts or trade-off curves are illustrated for both land-based and swimming snake robots with different numbers of links. Pareto fronts represent trade-offs between the objective functions. For example, how increasing the forward velocity results in increasing power consumption. Therefore, these curves are a very useful tool for the control and design of snake robots. The trade-off curve thus constitutes a very useful tool for both the control and design of bio-inspired snake robots. In particular, the operators or designers of bio-inspired snake robots can choose a Pareto optimal point based on the trade-off curve, given the preferred number of links on the robot. The optimal gait parameters

  4. Locomotion in simulated microgravity: gravity replacement loads

    Science.gov (United States)

    McCrory, Jean L.; Baron, Heidi A.; Balkin, Sandy; Cavanagh, Peter R.

    2002-01-01

    BACKGROUND: When an astronaut walks or runs on a treadmill in microgravity, a subject load device (SLD) is used to return him or her back to the treadmill belt. The gravity replacement load (GRL) in the SLD is transferred, via a harness, to the pelvis and/or the shoulders. This research compared comfort and ground reaction forces during treadmill running in a microgravity locomotion simulator at GRLs of 60%, 80%, and 100% of body weight (BW). Two harness designs (shoulder springs only (SSO) and waist and shoulder springs (WSS)) were used. HYPOTHESES: 1) The 100% BW gravity replacement load conditions would be comfortably tolerated and would result in larger ground reaction forces and loading rates than the lower load conditions, and 2) the WSS harness would be more comfortable than the SSO harness. METHODS: Using the Penn State Zero Gravity Locomotion Simulator (ZLS), 8 subjects ran at 2.0 m x s(-1) (4.5 mph) for 3 min at each GRL setting in each harness. Subjective ratings of harness comfort, ground reaction forces, and GRL data were collected during the final minute of exercise. RESULTS: The 100% BW loading conditions were comfortably tolerated (2.3 on a scale of 0-10), although discomfort increased as the GRL increased. There were no overall differences in perceived comfort between the two harnesses. The loading rates (27.1, 33.8, 39.1 BW x s(-1)) and the magnitudes of the first (1.0, 1.4, 1.6 BW) and second (1.3, 1.7, 1.9 BW) peaks of the ground reaction force increased with increasing levels (60, 80, 100% BW respectively) of GRL. CONCLUSIONS: Subjects were able to tolerate a GRL of 100% BW well. The magnitude of the ground reaction force peaks and the loading rate is directly related to the magnitude of the GRL.

  5. In-pipe micromachine locomotion via the inertial stepping principle

    Energy Technology Data Exchange (ETDEWEB)

    Yum, Young Jin [University of Ulsan, Ulsan (Korea, Republic of); Hwang, Han Sub [Suweon Science College, Suweon (Korea, Republic of); Kelemen, Michal; Maxim, Vladislav; Frankovsky, Peter [Technical University of Kosice, Kosice (Slovakia)

    2014-08-15

    This paper discusses an in-pipe inspection micromachine intended for locomotion inside a small diameter pipe. The micromachine locomotion is based on the inertial stepping principle, which utilizes the drive force of the two-body impact. The in-pipe micromachine contacts the pipe through the elastic bristles installed on the in-pipe machine and in two lines and crossways with respect to the micromachine axle. The paper describes the principle of locomotion and the dynamics by which the unknown of both the parameters and the relations are experimentally identified. Based on the results, a simulation model was created, and the results of the simulations were compared with experimental results.

  6. A survey report for the turning of biped locomotion robot

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Ichiro; Takanishi, Atsuo [Waseda Univ., Tokyo (Japan); Kume, Etsuo

    1992-12-01

    A mechanical design study of biped locomotion robots is going on at JAERI within the scope of the Human Acts Simulation Program (HASP). The design study at JAERI is of an arbitrarily mobile robot for inspection of nuclear facilities. A survey has been performed for collecting useful information from already existing biped locomotion robots. This is a survey report for the turning of biped locomotion robot: the WL-10R designed and developed at Waseda University. This report includes the control method of turning, machine model and control system. (author).

  7. Restless legs syndrome mimicking S1 radiculopathy.

    Science.gov (United States)

    Zambelis, Th; Wolgamuth, B R; Papoutsi, S N; Economou, N T

    2016-01-01

    Α case of a chronic idiopathic form of a severe type of Restless Legs Syndrome (RLS), which developed during pregnancy and persisted after this, misdiagnosed for 34 years as radiculopathy S1, is reported. In spite of the thorough clinical and laboratory investigation, in addition to constant changes of the therapeutic approach, the diagnosis of S1 radiculopathy could not be confirmed, resulting in a chronic clinical course; the latter was characterized by relapses and remissions not attributed or linked in any way to the treatment (various types of). In fact, it was due to a routine workup in a sleep clinic, where the patient was referred because of a coincident chronic insomnia (Restless Legs Syndrome is a known and important cause of insomnia/chronic insomnia), which resulted in a proper diagnosis and treatment of this case. With the use of Restless Legs Syndrome appropriate treatment (Pramipexole 0.18 mg taken at bedtime, a dopaminergic agent and Level A recommended drug for Restless Legs Syndrome) an excellent response and immediate elimination of symptoms was achieved. Restless Legs Syndrome may present with a variety of symptoms (with the most prominent shortly being reported with the acronym URGE: Urge to move the legs usually associated with unpleasant leg sensations, Rest induces symptoms, Getting active brings relief, Evening and night deteriorate symptoms); given the fact that Restless Legs Syndrome presents with a great variety and heterogeneity of symptoms (mostly pain, dysesthesia and paresthesia), which may occur in several other diseases (the so called "RLS mimics"), proper diagnosis of Restless Legs Syndrome usually fails. Restless Legs Syndrome misinterpreted as S1 radiculopathy, to the best of our knowledge, has not been reported yet in the literature. Here, case history, clinical course and common RLS mimics are presented. Different forms of Restless Legs Syndrome manifestations, which are commonly -as in this case- misinterpreted due to their

  8. 49 CFR 230.90 - Draw gear between steam locomotive and tender.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Draw gear between steam locomotive and tender. 230... Steam Locomotives and Tenders Draw Gear and Draft Systems § 230.90 Draw gear between steam locomotive and tender. (a) Maintenance and testing. The draw gear between the steam locomotive and tender...

  9. Intensive treatment of leg lymphedema

    Directory of Open Access Journals (Sweden)

    Pereira de Godoy Jose

    2010-01-01

    Full Text Available Background: Despite of all the problems caused by lymphedema, this disease continues to affect millions of people worldwide. Thus, the identification of the most efficacious forms of treatment is necessary. Aim: The aim of this study was to evaluate a novel intensive outpatient treatment for leg lymphedema. Methods: Twenty-three legs of 19 patients were evaluated in a prospective randomized study. The inclusion criteria were patients with Grade II and III lymphedema, where the difference, measured by volumetry, between the affected limb below the knee and the healthy limb was greater than 1.5 kg. Intensive treatment was carried out for 6- to 8-h sessions in the outpatient clinic. Analysis of variance was utilized for statistical analysis with an alpha error of 5% (P-value < 0.05 being considered significant. Results: All limbs had significant reductions in size with the final mean loss being 81.1% of the volume of edema. The greatest losses occurred in the first week (P-value < 0.001. Losses of more than 90% of the lymphedema occurred in 9 (39.13% patients; losses of more than 80% in 13 (56.52%, losses of more than 70% in 17 (73.91% and losses of more than 50% were recorded for 95.65% of the patients; only 1 patient lost less than 50% (37.9% of the edema. Conclusion: The intensive treatment of lymphedema in the outpatient clinic can produce significant reductions in the volume of edema over a short period of time and can be recommended for any grade of lymphedema, in particular the more advanced degrees.

  10. Leg blood flow during static exercise.

    Science.gov (United States)

    Kilbom, A; Persson, J

    1982-01-01

    Leg blood flow was studied with the constant infusion dye technique during static exercise of the thigh muscles (quadriceps) and during hand-grips at 15 and 25-30% of MVC. Blood flow and oxygen uptake in the leg increased in quadriceps exercise and reached their highest values (around 1.21/min and 165 ml/min respectively) at 25-30% of MVC, whereas leg vascular resistance decreased. Regional circulatory adaptations and the oxygen uptake - leg blood flow relationship were in close agreement with the responses found in dynamic leg exercise. In view of the marked rise in intramuscular pressure previously observed during quadriceps contractions, a restriction of blood flow and an increased vascular resistance had been expected. Involuntary activation of leg muscles other than the quadriceps may explain the finding. Contractions of the contralateral quadriceps induced a slight increase in leg blood flow, whereas hand-grips had no influence on blood flow or vascular resistance in the leg. The distribution of the cardiac output during static contractions is discussed, and it is concluded that during hand-grips the increase in blood flow is predominantly distributed to the upper part of the body.

  11. Børns leg og eksperimenterende virksomhed

    DEFF Research Database (Denmark)

    Damgaard Warrer, Sarah; Broström, Stig

    Børns leg og eksperimenterende virksomhed er et rigt felt med mange perspektiver, indgangsvinkler og nuancer. I denne bog kædes leg og det eksperimenterende og skabende sammen som to gensidigt forbundne fænomener og belyses i pædagogisk og didaktisk perspektiv. Desuden beskrives potentialet i båd...

  12. Muscle activity of leg muscles during unipedal stance on therapy devices with different stability properties.

    Science.gov (United States)

    Wolburg, Thomas; Rapp, Walter; Rieger, Jochen; Horstmann, Thomas

    2016-01-01

    To test the hypotheses that less stable therapy devices require greater muscle activity and that lower leg muscles will have greater increases in muscle activity with less stable therapy devices than upper leg muscles. Cross-sectional laboratory study. Laboratory setting. Twenty-five healthy subjects. Electromyographic activity of four lower (gastrocnemius medialis, soleus, tibialis anterior, peroneus longus) and four upper leg muscles (vastus medialis and lateralis, biceps femoris, semitendinosus) during unipedal quiet barefoot stance on the dominant leg on a flat rigid surface and on five therapy devices with varying stability properties. Muscle activity during unipedal stance differed significantly between therapy devices (P leg) and therapy device (P = 0.985). Magnitudes of additional relative muscle activity for the respective therapy devices differed substantially among lower extremity muscles. The therapy devices offer a progressive increase in training intensity, and thus may be useful for incremental training programs in physiotherapeutic practice and sports training programs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Active and Inactive Leg Hemodynamics during Sequential Single-Leg Interval Cycling.

    Science.gov (United States)

    Gordon, Nicole; Abbiss, Chris R; Ihsan, Mohammed; Maiorana, Andrew J; Peiffer, Jeremiah J

    2018-01-11

    Leg order during sequential single-leg cycling (i.e. exercising both legs independently within a single session) may affect local muscular responses potentially influencing adaptations. This study examined the cardiovascular and skeletal muscle hemodynamic responses during double-leg and sequential single-leg cycling. Ten young healthy adults (28 ± 6 y) completed six 1-min double-leg intervals interspersed with one minute of passive recovery and, on a separate occasion, 12 (six with one leg followed by six with the other leg) 1-min single-leg intervals interspersed with one minute of passive recovery. Oxygen consumption, heart rate, blood pressure, muscle oxygenation, muscle blood volume and power output were measured throughout each session. Oxygen consumption, heart rate and power output were not different between sets of single-leg intervals but the average of both sets was lower than the double-leg intervals. Mean arterial pressure was higher during double-leg compared with sequential single-leg intervals (115 ± 9 mmHg vs. 104 ± 9 mmHg; p<0.05) and higher during the initial compared with second set of single-leg intervals (108 ± 10 mmHg vs. 101 ± 10 mmHg; p<0.05). The increase in muscle blood volume from baseline was similar between the active single-leg and double-leg (267 ± 150 μM[BULLET OPERATOR]cm vs. 214 ± 169 μM[BULLET OPERATOR]cm; p=0.26). The pattern of change in muscle blood volume from the initial to second set of intervals was significantly different (p<0.05) when the leg was active in the initial (-52.3 ± 111.6%) compared with second set (65.1 ± 152.9%). These data indicate that the order in which each leg performs sequential single-leg cycling influences the local hemodynamic responses, with the inactive muscle influencing the stimulus experienced by the contralateral leg.

  14. A modular artificial neural net for controlling a six-legged walking system.

    Science.gov (United States)

    Cruse, H; Bartling, C; Cymbalyuk, G; Dean, J; Dreifert, M

    1995-01-01

    A system that controls the leg movement of an animal or a robot walking over irregular ground has to ensure stable support for the body and at the same time propel it forward. To do so, it has to react adaptively to unpredictable features of the environment. As part of our study of the underlying mechanisms, we present here a model for the control of the leg movement of a 6-legged walking system. The model is based on biological data obtained from the stick insect. It represents a combined treatment of realistic kinematics and biologically motivated, adaptive gait generation. The model extends a previous algorithmic model by substituting simple networks of artificial neurons for the algorithms previously used to control leg state and interleg coordination. Each system controlling an individual leg consists of three subnets. A hierarchically superior net contains two sensory and two 'premotor' units; it rhythmically suppresses the output of one or the other of the two subordinate nets. These are continuously active. They might be called the 'swing module' and the 'stance module' because they are responsible for controlling the swing (return stroke) and the stance (power stroke) movements, respectively. The swing module consists of three motor units and seven sensory units. It can produce appropriate return stroke movements for a broad range of initial and final positions, can cope with mechanical disturbances of the leg movement, and is able to react to an obstacle which hinders the normal performance of the swing movement. The complete model is able to walk at different speeds over irregular surfaces. The control system rapidly reestablishes a stable gait when the movement of the legs is disturbed.

  15. Hybrid Locomotive for Energy Savings and Reduced Emissions

    Science.gov (United States)

    2017-08-01

    Norfolk Southern Corporation (NS) and Pennsylvania State University tested several different battery systems in hybrid locomotives. Advanced lithium-ion battery technology was the only kind that displayed the capacity to perform in heavy switching or...

  16. Vibrational Locomotion Enabling Subsurface Exploration of Unconsolidated Regolith Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The idea of vibrational locomotion is based on vibrational-fluidization in ISRU reactor systems, which has proven very effective for regolith mixing. The vibrating...

  17. Test requirements of locomotive fuel tank blunt impact tests

    Science.gov (United States)

    2013-10-15

    The Federal Railroad Administrations Office of Research : and Development is conducting research into passenger : locomotive fuel tank crashworthiness. A series of impact tests : are planned to measure fuel tank deformation under two types : of dy...

  18. Spatio-temporal problems of locomotion control

    International Nuclear Information System (INIS)

    Smolyaninov, Vladimir V

    2000-01-01

    The problem of the spatio-temporal construction of legged movements involves structural freedoms due to the multi-link structure of the extremities, kinematic freedoms of the stepping cycle, and interextremity coordination freedoms, whose purposive organization is established by means of appropriate synergies, i.e. additional functional links the brain's control system forms. The main focus of attention in this work is on the kinematic and coordination synergies of the legged movements of humans and animals. The comparative historical analysis of experimental data and modelling metaphors concentrates on obtaining a unified description, whereas the ultimate mathematical metaphor reduces to space-time geometry, with base step synergies as its invariants. Thus, the concept of a synergetic organization for biomechanical movement freedoms is transformed to the geochronometry concept, actually a modification of Minkowskian geometry. To determine the spectrum of possible geochronometries, the consequences of a generalized 'postulate of a constant speed of light' are studied and different models of wave chronometers compared. (reviews of topical problems)

  19. Effect of leg length on ROM, VJ and leg dexterity in dance.

    Science.gov (United States)

    Wyon, M A; Nevill, A M; Dekker, K; Brown, D D; Clarke, F; Pelly, J; Koutedakis, Y

    2010-09-01

    We investigated the associations between leg length and specific ballet movements in different skill groups. Volunteers were from an undergraduate dance programme (n=18), a pre-professional school (n=43) and from an elite classical ballet company (n=45). Individual data were collected for anthropometry, vertical jump, leg dexterity, and leg active and passive ROM. ANCOVA identified both main effects as significant with regard to vertical jump (gender Peffects with gender, skill or leg length. Active and passive range of motion noted gender (P=0.001) and skill (Peffects of leg length on fundamental ballet skills. The longer legs that benefit vertical jump have a negative influence on range of motion and leg dexterity except for highly skilled dancers, who through skill, seem to have overcome the effects of some of these dichotomies. Georg Thieme Verlag KG Stuttgart . New York.

  20. Crawling beneath the free surface: Water snail locomotion

    OpenAIRE

    Lee, Sungyon; Bush, John W. M.; Hosoi, A. E.; Lauga, Eric

    2008-01-01

    Land snails move via adhesive locomotion. Through muscular contraction and expansion of their foot, they transmit waves of shear stress through a thin layer of mucus onto a solid substrate. Since a free surface cannot support shear stress, adhesive locomotion is not a viable propulsion mechanism for water snails that travel inverted beneath the free surface. Nevertheless, the motion of the freshwater snail, Sorbeoconcha physidae, is reminiscent of that of its terrestrial counterparts, being g...

  1. Design of Mine Locomotive System Based on CAN Bus

    OpenAIRE

    Li Yuanhong; Zhang Quanzhu; Zhang Wenshan

    2017-01-01

    Based on CAN bus, this paper studies the system control and management system of locomotive in mine, analyzes the working principle of locomotive system, gives the CAN bus scheme, hardware circuit design and CAN communication protocol, and implements long-distance, high-reliability communication function and remote monitoring function. Experiments show that the auxiliary system based on CAN bus control easier, operation more secure, as well as improving the control performance and service lif...

  2. Locomotion in Lymphocytes is Altered by Differential PKC Isoform Expression

    Science.gov (United States)

    Sundaresan, A.; Risin, D.; Pellis, N. R.

    1999-01-01

    Lymphocyte locomotion is critical for proper elicitation of the immune response. Locomotion of immune cells via the interstitium is essential for optimal immune function during wound healing, inflammation and infection. There are conditions which alter lymphocyte locomotion and one of them is spaceflight. Lymphocyte locomotion is severely inhibited in true spaceflight (true microgravity) and in rotating wall vessel culture (modeled microgravity). When lymphocytes are activated prior to culture in modeled microgravity, locomotion is not inhibited and the levels are comparable to those of static cultured lymphocytes. When a phorbol ester (PMA) is used in modeled microgravity, lymphocyte locomotion is restored by 87%. This occurs regardless if PMA is added after culture in the rotating wall vessel or during culture. Inhibition of DNA synthesis also does not alter restoration of lymphocyte locomotion by PMA. PMA is a direct activator of (protein kinase C) PKC . When a calcium ionophore, ionomycin is used it does not possess any restorative properties towards locomotion either alone or collectively with PMA. Since PMA brings about restoration without help from calcium ionophores (ionomycin), it is infer-red that calcium independent PKC isoforms are involved. Changes were perceived in the protein levels of PKC 6 where levels of the protein were downregulated at 24,72 and 96 hours in untreated rotated cultures (modeled microgravity) compared to untreated static (1g) cultures. At 48 hours there is an increase in the levels of PKC & in the same experimental set up. Studies on transcriptional and translational patterns of calcium independent isoforms of PKC such as 8 and E are presented in this study.

  3. Multi-modal locomotion: from animal to application

    International Nuclear Information System (INIS)

    Lock, R J; Burgess, S C; Vaidyanathan, R

    2014-01-01

    The majority of robotic vehicles that can be found today are bound to operations within a single media (i.e. land, air or water). This is very rarely the case when considering locomotive capabilities in natural systems. Utility for small robots often reflects the exact same problem domain as small animals, hence providing numerous avenues for biological inspiration. This paper begins to investigate the various modes of locomotion adopted by different genus groups in multiple media as an initial attempt to determine the compromise in ability adopted by the animals when achieving multi-modal locomotion. A review of current biologically inspired multi-modal robots is also presented. The primary aim of this research is to lay the foundation for a generation of vehicles capable of multi-modal locomotion, allowing ambulatory abilities in more than one media, surpassing current capabilities. By identifying and understanding when natural systems use specific locomotion mechanisms, when they opt for disparate mechanisms for each mode of locomotion rather than using a synergized singular mechanism, and how this affects their capability in each medium, similar combinations can be used as inspiration for future multi-modal biologically inspired robotic platforms. (topical review)

  4. Serotonin influences locomotion in the nudibranch mollusc Melibe leonina.

    Science.gov (United States)

    Lewis, Stefanie L; Lyons, Deborah E; Meekins, Tiffanie L; Newcomb, James M

    2011-06-01

    Serotonin (5-HT) influences locomotion in many animals, from flatworms to mammals. This study examined the effects of 5-HT on locomotion in the nudibranch mollusc Melibe leonina (Gould, 1852). M. leonina exhibits two modes of locomotion, crawling and swimming. Animals were bath-immersed in a range of concentrations of 5-HT or injected with various 5-HT solutions into the hemolymph and then monitored for locomotor activity. In contrast to other gastropods studied, M. leonina showed no significant effect of 5-HT on the distance crawled or the speed of crawling. However, the highest concentration (10(-3) mol l(-1) for bath immersion and 10(-5) mol l(-1) for injection) significantly increased the time spent swimming and the swimming speed. The 5-HT receptor antagonist methysergide inhibited the influence of 5-HT on the overall amount of swimming but not on swimming speed. These results suggest that 5-HT influences locomotion at the behavioral level in M. leonina. In conjunction with previous studies on the neural basis of locomotion in M. leonina, these results also suggest that this species is an excellent model system for investigating the 5-HT modulation of locomotion.

  5. Limited locomotive ability relaxed selective constraints on molluscs mitochondrial genomes.

    Science.gov (United States)

    Sun, Shao'e; Li, Qi; Kong, Lingfeng; Yu, Hong

    2017-09-06

    Mollusca are the second largest phylum in the animal kingdom with different types of locomotion. Some molluscs are poor-migrating, while others are free-moving or fast-swimming. Most of the energy required for locomotion is provided by mitochondria via oxidative phosphorylation. Here, we conduct a comparative genomic analysis of 256 molluscs complete mitochondrial genomes and evaluate the role of energetic functional constraints on the protein-coding genes, providing a new insight into mitochondrial DNA (mtDNA) evolution. The weakly locomotive molluscs, compared to strongly locomotive molluscs, show significantly higher Ka/Ks ratio, which suggest they accumulated more nonsynonymous mutations in mtDNA and have experienced more relaxed evolutionary constraints. Eleven protein-coding genes (CoxI, CoxII, ATP6, Cytb, ND1-6, ND4L) show significant difference for Ka/Ks ratios between the strongly and weakly locomotive groups. The relaxation of selective constraints on Atp8 arise in the common ancestor of bivalves, and the further relaxation occurred in marine bivalves lineage. Our study thus demonstrates that selective constraints relevant to locomotive ability play an essential role in evolution of molluscs mtDNA.

  6. A subset of interneurons required for Drosophila larval locomotion.

    Science.gov (United States)

    Yoshikawa, Shingo; Long, Hong; Thomas, John B

    2016-01-01

    Efforts to define the neural circuits generating locomotor behavior have produced an initial understanding of some of the components within the spinal cord, as well as a basic understanding of several invertebrate motor pattern generators. However, how these circuits are assembled during development is poorly understood. We are defining the neural circuit that generates larval locomotion in the genetically tractable fruit fly Drosophila melanogaster to study locomotor circuit development. Forward larval locomotion involves a stereotyped posterior-to-anterior segmental translocation of body wall muscle contraction and is generated by a relatively small number of identified muscles, motor and sensory neurons, plus an unknown number of the ~270 bilaterally-paired interneurons per segment of the 1st instar larva. To begin identifying the relevant interneurons, we have conditionally inactivated synaptic transmission of interneuron subsets and assayed for the effects on locomotion. From this screen we have identified a subset of 25 interneurons per hemisegment, called the lateral locomotor neurons (LLNs), that are required for locomotion. Both inactivation and constitutive activation of the LLNs disrupt locomotion, indicating that patterned output of the LLNs is required. By expressing a calcium indicator in the LLNs, we found that they display a posterior-to-anterior wave of activity within the CNS corresponding to the segmental translocation of the muscle contraction wave. Identification of the LLNs represents the first step toward elucidating the circuit generating larval locomotion. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Steerable Hopping Six-Legged Robot

    Science.gov (United States)

    Younse, Paulo; Aghazarian, Hrand

    2010-01-01

    The figure depicts selected aspects of a six-legged robot that moves by hopping and that can be steered in the sense that it can be launched into a hop in a controllable direction. This is a prototype of hopping robots being developed for use in scientific exploration of rough terrain on remote planets that have surface gravitation less than that of Earth. Hopping robots could also be used on Earth, albeit at diminished hopping distances associated with the greater Earth gravitation. The upper end of each leg is connected through two universal joints to an upper and a lower hexagonal frame, such that the tilt of the leg depends on the relative position of the two frames. Two non-back-driveable worm-gear motor drives are used to control the relative position of the two frames along two axes 120 apart, thereby controlling the common tilt of all six legs and thereby, further, controlling the direction of hopping. Each leg includes an upper and a lower aluminum frame segment with a joint between them. A fiberglass spring, connected via hinges to both segments, is used to store hopping energy prior to launch into a hop and to cushion the landing at the end of the hop. A cable for loading the spring is run into each leg through the center of the universal joints and then down along the center lines of the segments to the lower end of the leg. A central spool actuated by a motor with a harmonic drive and an electromagnetic clutch winds in all six cables to compress all six springs (thereby also flexing all six legs) simultaneously. To ensure that all the legs push off and land in the same direction, timing- belt pulley drives are attached to the leg segments, restricting the flexing and extension of all six legs to a common linear motion. In preparation for a hop, the spool can be driven to load the spring legs by an amount corresponding to a desired hop distance within range. The amount of compression can be computed from the reading of a shaft-angle encoder that

  8. Chair rising exercise is more effective than one-leg standing exercise in improving dynamic body balance: a randomized controlled trial.

    Science.gov (United States)

    Yamashita, F; Iwamoto, J; Osugi, T; Yamazaki, M; Takakuwa, M

    2012-06-01

    A randomized controlled trial was conducted to compare the effect of a one-leg standing exercise and a chair-rising exercise on body balance in patients with locomotive disorders. Thirty ambulatory patients (mean age: 66.6 years) were randomly divided into two groups (n=15 in each group): a one-leg standing exercise group and a chair-rising exercise group. All the participants performed calisthenics of the major muscles, a tandem gait exercise, and a stepping exercise. The exercises were performed 3 days per week, and the study period was 5 months. Physical function was evaluated at baseline and at one-month intervals. No significant differences in the baseline characteristics were observed between the two groups. After the 5-month exercise program, the timed up and go, one-leg standing time, and tandem gait time improved significantly in the one-leg standing exercise group, while the walking time and chair-rising time in addition to above parameters improved significantly in the chair-rising exercise group. The improvements in the walking time, chair-rising time, and tandem gait time were significantly greater in the chair-rising exercise group than in the one-leg standing exercise group. The present study showed that the chair-rising exercise was more effective than the one-leg standing exercise for improving walking velocity and dynamic body balance.

  9. Advanced underground Vehicle Power and Control: The locomotive Research Platform

    Energy Technology Data Exchange (ETDEWEB)

    Vehicle Projects LLC

    2003-01-28

    Develop a fuelcell mine locomotive with metal-hydride hydrogen storage. Test the locomotive for fundamental limitations preventing successful commercialization of hydride fuelcells in underground mining. During Phase 1 of the DOE-EERE sponsored project, FPI and its partner SNL, completed work on the development of a 14.4 kW fuelcell power plant and metal-hydride energy storage. An existing battery-electric locomotive with similar power requirements, minus the battery module, was used as the base vehicle. In March 2001, Atlas Copco Wagner of Portland, OR, installed the fuelcell power plant into the base vehicle and initiated integration of the system into the vehicle. The entire vehicle returned to Sandia in May 2001 for further development and integration. Initial system power-up took place in December 2001. A revision to the original contract, Phase 2, at the request of DOE Golden Field Office, established Vehicle Projects LLC as the new prime contractor,. Phase 2 allowed industry partners to conduct surface tests, incorporate enhancements to the original design by SNL, perform an extensive risk and safety analysis, and test the fuelcell locomotive underground under representative production mine conditions. During the surface tests one of the fuelcell stacks exhibited reduced power output resulting in having to replace both fuelcell stacks. The new stacks were manufactured with new and improved technology resulting in an increase of the gross power output from 14.4 kW to 17 kW. Further work by CANMET and Hatch Associates, an engineering consulting firm specializing in safety analysis for the mining industry, both under subcontract to Vehicle Projects LLC, established minimum requirements for underground testing. CANMET upgraded the Programmable Logic Control (PLC) software used to monitor and control the fuelcell power plant, taking into account locomotive operator's needs. Battery Electric, a South Africa manufacturer, designed and manufactured (at no cost

  10. Sensory modulation of movement, posture and locomotion.

    Science.gov (United States)

    Saradjian, A H

    2015-11-01

    During voluntary movement, there exists a well known functional sensory attenuation of afferent inputs, which allows us to discriminate between information related to our own movements and those arising from the external environment. This attenuation or 'gating' prevents some signals from interfering with movement elaboration and production. However, there are situations in which certain task-relevant sensory inputs may not be gated. This review begins by identifying the prevalent findings in the literature with specific regard to the somatosensory modality, and reviews the many cases of classical sensory gating phenomenon accompanying voluntary movement and their neural basis. This review also focuses on the newer axes of research that demonstrate that task-specific sensory information may be disinhibited or even facilitated during engagement in voluntary actions. Finally, a particular emphasis will be placed on postural and/or locomotor tasks involving strong somatosensory demands, especially for the setting of the anticipatory postural adjustments observed prior the initiation of locomotion. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  11. EVALUATION OF DYNAMIC INDICATORS OF SIX-AXLE LOCOMOTIVE

    Directory of Open Access Journals (Sweden)

    S. V. Myamlin

    2015-04-01

    Full Text Available Purpose. The paper is devoted to dynamic characteristics evaluation of the locomotive with prospective design and determination the feasibility of its use on the Ukrainian railways. Methodology. The methods of mathematical and computer modeling of the dynamics of railway vehicles, as well as methods for the numerical integration of systems of ordinary nonlinear differential equations were used to solve the problem. Findings. The calculated diagram of a locomotive on three-axle bogies was built to solve the problem, and it is a system of rigid bodies connected by various elements of rheology. The mathematical model of the locomotive movement, allowing studying its spatial vibrations at driving on straight and curved sections of the track with random irregularities in plan and profile was developed with use of this calculated diagram. At compiling the mathematical model took into account both geometric (nonlinearity profile of the wheel roll surface and physical nonlinearity of the system (the work forces of dry friction, nonlinearity characteristics of interaction forces between wheels and rails. The multivariate calculations, which allowed assessing the dynamic qualities of the locomotive at its movement along straight and curved sections of the track, were realized with the use of computer modeling. The smoothness movement indicators of the locomotive in horizontal and vertical planes, frame strength, coefficients of vertical dynamics in the first and second stages of the suspension, the load factor of resistance against the derailment of the wheel from the rail were determined at the period of research. In addition, a comparison of the obtained results with similar characteristics is widely used on the Ukrainian railways in six-axle locomotive TE 116. The influence of speed and technical state of the track on the locomotive traffic safety was determined.Originality. A mathematical model of the spatial movement of a six-axle locomotive with

  12. INFORMATION-MEASURING TEST SYSTEM OF DIESEL LOCOMOTIVE HYDRAULIC TRANSMISSIONS

    Directory of Open Access Journals (Sweden)

    I. V. Zhukovytskyy

    2015-08-01

    Full Text Available Purpose. The article describes the process of developing the information-measuring test system of diesel locomotives hydraulic transmission, which gives the possibility to obtain baseline data to conduct further studies for the determination of the technical condition of diesel locomotives hydraulic transmission. The improvement of factory technology of post-repair tests of hydraulic transmissions by automating the existing hydraulic transmission test stands according to the specifications of the diesel locomotive repair enterprises was analyzed. It is achieved based on a detailed review of existing foreign information-measuring test systems for hydraulic transmission of diesel locomotives, BelAZ earthmover, aircraft tug, slag car, truck, BelAZ wheel dozer, some brands of tractors, etc. The problem for creation the information-measuring test systems for diesel locomotive hydraulic transmission is being solved, starting in the first place from the possibility of automation of the existing test stand of diesel locomotives hydraulic transmission at Dnipropetrovsk Diesel Locomotive Repair Plant "Promteplovoz". Methodology. In the work the researchers proposed the method to create a microprocessor automated system of diesel locomotives hydraulic transmission stand testing in the locomotive plant conditions. It acts by justifying the selection of the necessary sensors, as well as the application of the necessary hardware and software for information-measuring systems. Findings. Based on the conducted analysis there was grounded the necessity of improvement the plant hydraulic transmission stand testing by creating a microprocessor testing system, supported by the experience of developing such systems abroad. Further research should be aimed to improve the accuracy and frequency of data collection by adopting the more modern and reliable sensors in tandem with the use of filtering software for electromagnetic and other interference. Originality. The

  13. Problems of locomotive wheel wear in fleet replacement

    Directory of Open Access Journals (Sweden)

    L.P. Lingaytis

    2013-08-01

    Full Text Available Purpose. To conduct a research and find out the causes of defects appearing on the wheel thread of freight locomotives 2М62 and SIEMENS ER20CF. Methodology. To find the ways to solve this problem comparing the locomotive designs and their operating conditions. Findings. After examining the nature of the wheel wear the main difference was found: in locomotives of the 2M62 line wears the wheel flange, and in the locomotives SIEMENS ER20CF – the tread surface. After installation on the 2M62 locomotive the lubrication system of flanges their wear rate significantly decreased. On the new freight locomotives SIEMENS ER20CF the flange lubrication systems of the wheel set have been already installed at the factory, however the wheel thread is wearing. As for locomotives 2M62, and on locomotives SIEMENS ER20CF most wear profile skating wheels of the first wheel set. On both locomotive lines the 2М62 and the SIEMENS ER20CF the tread profile of the first wheel set most of all is subject to the wear. After reaching the 170 000 km run, the tread surface of some wheels begins to crumble. There was a suspicion that the reason for crumb formation of the wheel surface may be insufficient or excessive wheel hardness or its chemical composition. In order to confirm or deny this suspicion the following studies were conducted: the examination of the rim surface, the study of the wheel metal hardness and the document analysis of the wheel production and their comparison with the results of wheel hardness measurement. Practical value. The technical condition of locomotives is one of the bases of safety and reliability of the rolling stock. The reduction of the wheel wear significantly reduces the operating costs of railway transport. After study completion it was found that there was no evidence to suggest that the ratio of the wheel-rail hardness could be the cause of the wheel surface crumbling.

  14. Hot Leg Piping Materials Issues

    International Nuclear Information System (INIS)

    V. Munne

    2006-01-01

    With Naval Reactors (NR) approval of the Naval Reactors Prime Contractor Team (NRPCT) recommendation to develop a gas cooled reactor directly coupled to a Brayton power conversion system as the space nuclear power plant (SNPP) for Project Prometheus (References a and b) the reactor outlet piping was recognized to require a design that utilizes internal insulation (Reference c). The initial pipe design suggested ceramic fiber blanket as the insulation material based on requirements associated with service temperature capability within the expected range, very low thermal conductivity, and low density. Nevertheless, it was not considered to be well suited for internal insulation use because its very high surface area and proclivity for holding adsorbed gases, especially water, would make outgassing a source of contaminant gases in the He-Xe working fluid. Additionally, ceramic fiber blanket insulating materials become very friable after relatively short service periods at working temperatures and small pieces of fiber could be dislodged and contaminate the system. Consequently, alternative insulation materials were sought that would have comparable thermal properties and density but superior structural integrity and greatly reduced outgassing. This letter provides technical information regarding insulation and materials issues for the Hot Leg Piping preconceptual design developed for the Project Prometheus space nuclear power plant (SNPP)

  15. Human Locomotion in Hypogravity: From Basic Research to Clinical Applications

    Directory of Open Access Journals (Sweden)

    Francesco Lacquaniti

    2017-11-01

    Full Text Available We have considerable knowledge about the mechanisms underlying compensation of Earth gravity during locomotion, a knowledge obtained from physiological, biomechanical, modeling, developmental, comparative, and paleoanthropological studies. By contrast, we know much less about locomotion and movement in general under sustained hypogravity. This lack of information poses a serious problem for human space exploration. In a near future humans will walk again on the Moon and for the first time on Mars. It would be important to predict how they will move around, since we know that locomotion and mobility in general may be jeopardized in hypogravity, especially when landing after a prolonged weightlessness of the space flight. The combination of muscle weakness, of wearing a cumbersome spacesuit, and of maladaptive patterns of locomotion in hypogravity significantly increase the risk of falls and injuries. Much of what we currently know about locomotion in hypogravity derives from the video archives of the Apollo missions on the Moon, the experiments performed with parabolic flight or with body weight support on Earth, and the theoretical models. These are the topics of our review, along with the issue of the application of simulated hypogravity in rehabilitation to help patients with deambulation problems. We consider several issues that are common to the field of space science and clinical rehabilitation: the general principles governing locomotion in hypogravity, the methods used to reduce gravity effects on locomotion, the extent to which the resulting behavior is comparable across different methods, the important non-linearities of several locomotor parameters as a function of the gravity reduction, the need to use multiple methods to obtain reliable results, and the need to tailor the methods individually based on the physiology and medical history of each person.

  16. Human Locomotion in Hypogravity: From Basic Research to Clinical Applications

    Science.gov (United States)

    Lacquaniti, Francesco; Ivanenko, Yury P.; Sylos-Labini, Francesca; La Scaleia, Valentina; La Scaleia, Barbara; Willems, Patrick A.; Zago, Myrka

    2017-01-01

    We have considerable knowledge about the mechanisms underlying compensation of Earth gravity during locomotion, a knowledge obtained from physiological, biomechanical, modeling, developmental, comparative, and paleoanthropological studies. By contrast, we know much less about locomotion and movement in general under sustained hypogravity. This lack of information poses a serious problem for human space exploration. In a near future humans will walk again on the Moon and for the first time on Mars. It would be important to predict how they will move around, since we know that locomotion and mobility in general may be jeopardized in hypogravity, especially when landing after a prolonged weightlessness of the space flight. The combination of muscle weakness, of wearing a cumbersome spacesuit, and of maladaptive patterns of locomotion in hypogravity significantly increase the risk of falls and injuries. Much of what we currently know about locomotion in hypogravity derives from the video archives of the Apollo missions on the Moon, the experiments performed with parabolic flight or with body weight support on Earth, and the theoretical models. These are the topics of our review, along with the issue of the application of simulated hypogravity in rehabilitation to help patients with deambulation problems. We consider several issues that are common to the field of space science and clinical rehabilitation: the general principles governing locomotion in hypogravity, the methods used to reduce gravity effects on locomotion, the extent to which the resulting behavior is comparable across different methods, the important non-linearities of several locomotor parameters as a function of the gravity reduction, the need to use multiple methods to obtain reliable results, and the need to tailor the methods individually based on the physiology and medical history of each person. PMID:29163225

  17. Stable Isotope Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Tissue samples (skin, bone, blood, muscle) are analyzed for stable carbon, stable nitrogen, and stable sulfur analysis. Many samples are used in their entirety for...

  18. Leg pain (Osgood-Schlatter) (image)

    Science.gov (United States)

    Leg pain in older children or young adolescents can occur for many reasons. An Osgood-Schlatter lesion results from continued trauma to the anterior tibial bone and causes a visible lump below the knee.

  19. Support Leg Loading in Punt Kicking

    Science.gov (United States)

    Kermond, John; Konz, Stephen

    1978-01-01

    Maximum distance in football punt kicking is associated with a maximum force transfer to the ball rather than a maximum force transfer through the ground via the support leg. For maximum distance, tred lightly. (Author)

  20. Sturge-Weber syndrome - legs (image)

    Science.gov (United States)

    ... nervous system (neurocutaneous) and is associated with Port Wine Stain, red vascular markings on the face and other parts of the body (shown here on the legs). This is an unusual case, due to the large size of the lesion ( ...

  1. Leg or foot amputation - dressing change

    Science.gov (United States)

    ... patientinstructions/000018.htm Leg or foot amputation - dressing change To use the sharing features on this page, please enable JavaScript. You will need to change the dressing on your limb. This will help ...

  2. Wind-powered wheel locomotion, initiated by leaping somersaults, in larvae of the southeastern beach tiger beetle (Cicindela dorsalis media.

    Directory of Open Access Journals (Sweden)

    Alan Harvey

    2011-03-01

    Full Text Available Rapid movement is challenging for elongate, soft-bodied animals with short or no legs. Leaping is known for only a few animals with this "worm-like" morphology. Wheel locomotion, in which the animal's entire body rolls forward along a central axis, has been reported for only a handful of animals worldwide. Here we present the first documented case of wind-powered wheel locomotion, in larvae of the coastal tiger beetle Cicindela dorsalis media. When removed from their shallow burrows, larvae easily can be induced to enter a behavioral sequence that starts with leaping; while airborne, larvae loop their body into a rotating wheel and usually either "hit the ground rolling" or leap again. The direction larvae wheel is closely related to the direction in which winds are blowing; thus, all our larvae wheeled up-slope, as winds at our study site consistently blew from sea to land. Stronger winds increased both the proportion of larvae wheeling, and the distance traveled, exceeding 60 m in some cases. In addition, the proportion of larvae that wheel and the distance traveled by wheeling larvae are significantly greater on smooth sandy beaches than on beach surfaces made rough and irregular by pedestrian, equestrian, and vehicular traffic. Like other coastal species of tiger beetles, C. dorsalis media has suffered major declines in recent years that are clearly correlated with increased human impacts. The present study suggests that the negative effects of beach traffic may be indirect, preventing larvae from escaping from predators using wheel locomotion by disrupting the flat, hard surface necessary for efficient wheeling.

  3. Conjoined legs: Sirenomelia or caudal regression syndrome?

    OpenAIRE

    Das, Sakti Prasad; Ojha, Niranjan; Ganesh, G Shankar; Mohanty, Ram Narayan

    2013-01-01

    Presence of single umbilical persistent vitelline artery distinguishes sirenomelia from caudal regression syndrome. We report a case of a12-year-old boy who had bilateral umbilical arteries presented with fusion of both legs in the lower one third of leg. Both feet were rudimentary. The right foot had a valgus rocker-bottom deformity. All toes were present but rudimentary. The left foot showed absence of all toes. Physical examination showed left tibia vara. The chest evaluation in sitting re...

  4. Efficiency and Speed in Legged Robots

    Science.gov (United States)

    2011-03-22

    which we substitute into (4.42) : ( -mv s J O=-km+ mvc -k __ c __ V v 2 c c 46 (4.43) (4.44) (4.45) (4.46) to fInd the switching curve m 3 s...Legged Mechanisms. IVSS. Traverse City, MI Muench, P., Alexander, J., Quinn, R., & Aschenbeck, K. (2005) Pneumatic Spring for Legged Walker. SPIE

  5. Flexural characteristics of a stack leg

    International Nuclear Information System (INIS)

    Cook, J.

    1979-06-01

    A 30 MV tandem Van de Graaff accelerator is at present under construction at Daresbury Laboratory. The insulating stack of the machine is of modular construction, each module being 860 mm in length. Each live section stack module contains 8 insulating legs mounted between bulkhead rings. The design, fabrication (from glass discs bonded to stainless steel discs using an epoxy film adhesive) and testing of the stack legs is described. (U.K.)

  6. Observation of Point-Light-Walker Locomotion Induces Motor Resonance When Explicitly Represented; An EEG Source Analysis Study

    Directory of Open Access Journals (Sweden)

    Alberto Inuggi

    2018-03-01

    Full Text Available Understanding human motion, to infer the goal of others' actions, is thought to involve the observer's motor repertoire. One prominent class of actions, the human locomotion, has been object of several studies, all focused on manipulating the shape of degraded human figures like point-light walker (PLW stimuli, represented as walking on the spot. Nevertheless, since the main goal of the locomotor function is to displace the whole body from one position to the other, these stimuli might not fully represent a goal-directed action and thus might not be able to induce the same motor resonance mechanism expected when observing a natural locomotion. To explore this hypothesis, we recorded the event-related potentials (ERP of canonical/scrambled and translating/centered PLWs decoding. We individuated a novel ERP component (N2c over central electrodes, around 435 ms after stimulus onset, for translating compared to centered PLW, only when the canonical shape was preserved. Consistently with our hypothesis, sources analysis associated this component to the activation of trunk and lower legs primary sensory-motor and supplementary motor areas. These results confirm the role of own motor repertoire in processing human action and suggest that ERP can detect the associated motor resonance only when the human figure is explicitly involved in performing a meaningful action.

  7. Three cross leg flaps for lower leg reconstruction of Gustilo type III C open fracture

    Directory of Open Access Journals (Sweden)

    Kazufumi Sano

    2016-01-01

    Full Text Available A 60 year old male had Gustilo type III C open fracture of the right lower leg. After radical debridement, the large open defect including certain loss of the bone tissue was successfully augmented and covered, by consecutive three cross-leg flaps, which consisted of the free rectus abdominis musculocutaneous flap, the fibula osteocutaneous flap and the conventional sural flap. Although indication for amputation or preservation is decided with multiple factors in each case, a strategic combination of cross-leg flap, free flap, external fixation and vascular delay could increase the potential of preservation of the lower leg with even disastrous Gustilo type III C.

  8. Locomotive syndrome in the elderly: translation, cultural adaptation, and Brazilian validation of the tool 25-Question Geriatric Locomotive Function Scale.

    Science.gov (United States)

    Tavares, Daniela Regina Brandão; Santos, Fania Cristina

    The term Locomotive Syndrome refers to conditions in which the elderly are at high risk of inability to ambulate due to problems in locomotor system. For Locomotive Syndrome screening, the 25-Question Geriatric Locomotive Function Scale was created. The objective here was to translate, adapt culturally to Brazil, and study the psychometric properties of 25-Question Geriatric Locomotive Function Scale. The translation and cultural adaptation of 25-Question Geriatric Locomotive Function Scale were carried out, thus resulting in GLFS 25-P, whose psychometric properties were analyzed in a sample of 100 elderly subjects. Sociodemographic data on pain, falls, self-perceived health and basic and instrumental functionalities were determined. GLFS 25-P was applied three times: in one same day by two interviewers, and after 15 days, again by the first interviewer. GLFS 25-P showed a high internal consistency value according to Cronbach's alpha coefficient (0.942), and excellent reproducibility, according to intraclass correlation, with interobserver and intraobserver values of 97.6% and 98.4%, respectively (p<0.01). Agreements for each item of the instrument were considerable (between 0.248 and 0.673), according to Kappa statistic. In its validation, according to the Pearson's coefficient, regular and good correlations were obtained for the basic (BADL) and instrumental (IADL) activities of daily living, respectively (p<0.01). Statistically significant associations with chronic pain (p<0.001), falls (p=0.02) and self-perceived health (p<0.001) were found. A multivariate analysis showed a significantly higher risk of Locomotive Syndrome in the presence of chronic pain (OR 15.92, 95% CI 3.08-82.27) and with a worse self-perceived health (OR 0.23, 95% CI 0.07-0.79). GLFS 25-P proved to be a reliable and valid tool in Locomotive Syndrome screening for the elderly population. Copyright © 2016. Published by Elsevier Editora Ltda.

  9. Two-fluid model for locomotion under self-confinement

    Science.gov (United States)

    Reigh, Shang Yik; Lauga, Eric

    2017-09-01

    The bacterium Helicobacter pylori causes ulcers in the stomach of humans by invading mucus layers protecting epithelial cells. It does so by chemically changing the rheological properties of the mucus from a high-viscosity gel to a low-viscosity solution in which it may self-propel. We develop a two-fluid model for this process of swimming under self-generated confinement. We solve exactly for the flow and the locomotion speed of a spherical swimmer located in a spherically symmetric system of two Newtonian fluids whose boundary moves with the swimmer. We also treat separately the special case of an immobile outer fluid. In all cases, we characterize the flow fields, their spatial decay, and the impact of both the viscosity ratio and the degree of confinement on the locomotion speed of the model swimmer. The spatial decay of the flow retains the same power-law decay as for locomotion in a single fluid but with a decreased magnitude. Independent of the assumption chosen to characterize the impact of confinement on the actuation applied by the swimmer, its locomotion speed always decreases with an increase in the degree of confinement. Our modeling results suggest that a low-viscosity region of at least six times the effective swimmer size is required to lead to swimming with speeds similar to locomotion in an infinite fluid, corresponding to a region of size above ≈25 μ m for Helicobacter pylori.

  10. High performance p-type segmented leg of misfit-layered cobaltite and half-Heusler alloy

    International Nuclear Information System (INIS)

    Hung, Le Thanh; Van Nong, Ngo; Snyder, G. Jeffrey; Viet, Man Hoang; Balke, Benjamin; Han, Li; Stamate, Eugen; Linderoth, Søren; Pryds, Nini

    2015-01-01

    Highlights: • p-type segmented leg of oxide and half-Heusler was for the first time demonstrated. • The maximum conversion efficiency reached a value of about 5%. • The results are among the highest reported values so far for oxide-based legs. • Oxide-based segmented leg is very promising for generating electricity. - Abstract: In this study, a segmented p-type leg of doped misfit-layered cobaltite Ca 2.8 Lu 0.15 Ag 0.05 Co 4 O 9+δ and half-Heusler Ti 0.3 Zr 0.35 Hf 0.35 CoSb 0.8 Sn 0.2 alloy was fabricated and characterized. The thermoelectric properties of single components, segmented leg, and the electrical contact resistance of the joint part were measured as a function of temperature. The output power generation characteristics of segmented legs were characterized in air under various temperature gradients, ΔT, with the hot side temperature up to 1153 K. At ΔT ≈ 756 K, the maximum conversion efficiency reached a value of ∼5%, which is about 65% of that expected from the materials without parasitic losses. The long-term stability investigation for two weeks at the hot and cold side temperatures of 1153/397 K shows that the segmented leg has good durability as a result of stable and low electrical resistance contacts

  11. Effect of a planar interface on time-averaged locomotion of a spherical squirmer in a viscoelastic fluid

    Science.gov (United States)

    Yazdi, Shahrzad; Borhan, Ali

    2017-09-01

    We examine the time-averaged locomotion of a spherical squirmer with reciprocal surface motion near a planar interface in a viscoelastic fluid. The system dynamics is investigated through a phase portrait in the swimming orientation and distance from the interface for three types of swimming gaits, namely, pullers, pushers, and neutral swimmers. To examine the kinematics of locomotion near different types of boundaries, the ratio of viscosities of the two phases adjacent to the planar interface is varied. Our results show that the near-wall attraction layer previously reported for a two-dimensional squirmer does not exist for spherical pullers and pushers. However, the presence of a stable node can attract the swimmer to the vicinity of the interface, depending on the initial swimming direction. In contrast to a two-dimensional neutral squirmer that always swims towards a no-slip boundary, a spherical neutral swimmer moves away from the interface, but the direction of time-averaged rotational velocity favors eventual entrapment of the squirmer at a stable node. We show that the position of the stable node depends on the boundary type and is furthest from the interface for a no-slip boundary.

  12. Single-unit pattern generators for quadruped locomotion

    DEFF Research Database (Denmark)

    Morse, Gregory; Risi, Sebastian; Snyder, Charles R

    2013-01-01

    Legged robots can potentially venture beyond the limits of wheeled vehicles. While creating controllers for such robots by hand is possible, evolutionary algorithms are an alternative that can reduce the burden of hand-crafting robotic controllers. Although major evolutionary approaches to legged...

  13. Coupler dynamic performance analysis of heavy haul locomotives

    Science.gov (United States)

    Ma, Weihua; Luo, Shihui; Song, Rongrong

    2012-09-01

    In this paper, a train dynamic model was developed to study the dynamic performance of heavy haul locomotives, taking into account the use of different coupler and buffer systems under conditions of severe longitudinal coupler compressive forces. The model consists of four locomotives each having 38 independent degrees of freedom and one dummy freight vehicle connected to each other by couplers and buffers. Simulation results showed that the longitudinal coupler compressive forces withstood by large rotation angle couplers with coupler shoulders were larger than those withstood by small rotation angle couplers. The results obtained for the large rotation angle coupler model showed that it had higher safety curve negotiation speeds. Due to the smaller static impedance, it was found that large capacity elastic clay (or cement) buffers cannot satisfy the requirement of heavy haul locomotives during cycle braking in long heavy downgraded tracks; the use of friction clay buffers can solve this problem.

  14. Postural dependence of human locomotion during gait initiation.

    Science.gov (United States)

    Mille, Marie-Laure; Simoneau, Martin; Rogers, Mark W

    2014-12-15

    The initiation of human walking involves postural motor actions for body orientation and balance stabilization that must be effectively integrated with locomotion to allow safe and efficient transport. Our ability to coordinately adapt these functions to environmental or bodily changes through error-based motor learning is essential to effective performance. Predictive compensations for postural perturbations through anticipatory postural adjustments (APAs) that stabilize mediolateral (ML) standing balance normally precede and accompany stepping. The temporal sequencing between these events may involve neural processes that suppress stepping until the expected stability conditions are achieved. If so, then an unexpected perturbation that disrupts the ML APAs should delay locomotion. This study investigated how the central nervous system (CNS) adapts posture and locomotion to perturbations of ML standing balance. Healthy human adults initiated locomotion while a resistance force was applied at the pelvis to perturb posture. In experiment 1, using random perturbations, step onset timing was delayed relative to the APA onset indicating that locomotion was withheld until expected stability conditions occurred. Furthermore, stepping parameters were adapted with the APAs indicating that motor prediction of the consequences of the postural changes likely modified the step motor command. In experiment 2, repetitive postural perturbations induced sustained locomotor aftereffects in some parameters (i.e., step height), immediate but rapidly readapted aftereffects in others, or had no aftereffects. These results indicated both rapid but transient reactive adaptations in the posture and gait assembly and more durable practice-dependent changes suggesting feedforward adaptation of locomotion in response to the prevailing postural conditions. Copyright © 2014 the American Physiological Society.

  15. Locomotion speeds from trackways: Predatory dinosaurs moved faster than herbivorous dinosaurs

    Science.gov (United States)

    Lee, Scott A.

    2014-03-01

    Fossilized trackways from dinosaurs leaves evidence of their locomotion from the stride length S and foot length F which yields the leg length L. From studies of living animals, it is known that a walking animal has a relative stride length RSL (= S/L) less than 2 and a running animal has a RSL greater than 2. A statistical analysis was performed of trackways associated with three groups of herbivorous dinosaurs: sauropods (N = 23), the armored ankylosaurs and stegosaurs (N = 10), and the unarmored ornithopods (N = 23) as well as the predatory theropods (N = 35). The average RSL of the sauropods and the armored dinosaurs were both 0.9 +/- 0.3. The ornithopods had an average RSL of 1.2 +/- 0.2. None of the trackways associated with herbivorous dinosaurs have an RSL greater than 1.5, indicating that they were all walking. The theropods showed the fastest and most varied locomomtion: their highest average RSL was 1.8 +/- 0.7. Nine of the theropod trackways had an RSL greater than 2.0, indicating that the dinosaurs were running when they made those trackways. One of the theropod trackways had an RSL of 4.5, indicating that it was running very fast compared to its body length.

  16. Energy evaluation of a bio-inspired gait modulation method for quadrupedal locomotion.

    Science.gov (United States)

    Fukuoka, Yasuhiro; Fukino, Kota; Habu, Yasushi; Mori, Yoshikazu

    2015-08-04

    We have proposed a bio-inspired gait modulation method, by means of which a simulated quadruped model can successfully perform smooth, autonomous gait transitions from a walk to a trot to a gallop, as observed in animals. The model is equipped with a rhythm generator called a central pattern generator (CPG) for each leg. The lateral neighbouring CPGs are mutually and inhibitorily coupled, and the CPG network is hardwired to produce a trot. Adding only the simple feedback of body tilt to each CPG, which was based on input from the postural reflex, led to the emergence of un-programmed walking and galloping at low and high speeds, respectively. Although this autonomous gait transition was a consequence of postural adaptation, it coincidentally also resulted in the minimization of energy consumption, as observed in real animals. In simulations at a variety of constant speeds the energy cost was lower for walking at low speeds and for galloping at high speeds than it was for trotting. Moreover, each gait transition occurred at the optimal speed, such that the model minimised its energy consumption. Thus, gait transitions in simulations that included the bio-inspired gait modulation method were similar to those observed in animals, even from the perspective of energy consumption. This method should therefore be a preferred choice for motion generation and control in biomimetic quadrupedal locomotion.

  17. Soft swimming: exploiting deformable interfaces for low reynolds number locomotion.

    Science.gov (United States)

    Trouilloud, Renaud; Yu, Tony S; Hosoi, A E; Lauga, Eric

    2008-07-25

    Reciprocal movement cannot be used for locomotion at low Reynolds number in an infinite fluid or near a rigid surface. Here we show that this limitation is relaxed for a body performing reciprocal motions near a deformable interface. Using physical arguments and scaling relationships, we show that the nonlinearities arising from reciprocal flow-induced interfacial deformation rectify the periodic motion of the swimmer, leading to locomotion. Such a strategy can be used to move toward, away from, and parallel to any deformable interface as long as the length scales involved are smaller than intrinsic scales, which we identify. A macroscale experiment of flapping motion near a free surface illustrates this new result.

  18. Economic aspects of advanced coal-fired gas turbine locomotives

    Science.gov (United States)

    Liddle, S. G.; Bonzo, B. B.; Houser, B. C.

    1983-01-01

    Increases in the price of such conventional fuels as Diesel No. 2, as well as advancements in turbine technology, have prompted the present economic assessment of coal-fired gas turbine locomotive engines. A regenerative open cycle internal combustion gas turbine engine may be used, given the development of ceramic hot section components. Otherwise, an external combustion gas turbine engine appears attractive, since although its thermal efficiency is lower than that of a Diesel engine, its fuel is far less expensive. Attention is given to such a powerplant which will use a fluidized bed coal combustor. A life cycle cost analysis yields figures that are approximately half those typical of present locomotive engines.

  19. Decoding the organization of spinal circuits that control locomotion

    Science.gov (United States)

    Kiehn, Ole

    2016-01-01

    Unravelling the functional operation of neuronal networks and linking cellular activity to specific behavioural outcomes are among the biggest challenges in neuroscience. In this broad field of research, substantial progress has been made in studies of the spinal networks that control locomotion. Through united efforts using electrophysiological and molecular genetic network approaches and behavioural studies in phylogenetically diverse experimental models, the organization of locomotor networks has begun to be decoded. The emergent themes from this research are that the locomotor networks have a modular organization with distinct transmitter and molecular codes and that their organization is reconfigured with changes to the speed of locomotion or changes in gait. PMID:26935168

  20. Stable convergence and stable limit theorems

    CERN Document Server

    Häusler, Erich

    2015-01-01

    The authors present a concise but complete exposition of the mathematical theory of stable convergence and give various applications in different areas of probability theory and mathematical statistics to illustrate the usefulness of this concept. Stable convergence holds in many limit theorems of probability theory and statistics – such as the classical central limit theorem – which are usually formulated in terms of convergence in distribution. Originated by Alfred Rényi, the notion of stable convergence is stronger than the classical weak convergence of probability measures. A variety of methods is described which can be used to establish this stronger stable convergence in many limit theorems which were originally formulated only in terms of weak convergence. Naturally, these stronger limit theorems have new and stronger consequences which should not be missed by neglecting the notion of stable convergence. The presentation will be accessible to researchers and advanced students at the master's level...

  1. A Specific Population of Reticulospinal Neurons Controls the Termination of Locomotion

    OpenAIRE

    Juvin, Laurent; Grätsch, Swantje; Trillaud-Doppia, Emilie; Gariépy, Jean-François; Büschges, Ansgar; Dubuc, Réjean

    2016-01-01

    Locomotion requires the proper sequencing of neural activity to start, maintain, and stop it. Recently, brainstem neurons were shown to specifically stop locomotion in mammals. However, the cellular properties of these neurons and their activity during locomotion are still unknown. Here, we took advantage of the lamprey model to characterize the activity of a cell population that we now show to be involved in stopping locomotion. We find that these neurons display a burst of spikes that coinc...

  2. One-legged endurance training: leg blood flow and oxygen extraction during cycling exercise

    DEFF Research Database (Denmark)

    Rud, B; Foss, O; Krustrup, Peter

    2012-01-01

    Aim: As a consequence of enhanced local vascular conductance, perfusion of muscles increases with exercise intensity to suffice the oxygen demand. However, when maximal oxygen uptake (VO(2) max) and cardiac output are approached, the increase in conductance is blunted. Endurance training increases...... muscle metabolic capacity, but to what extent that affects the regulation of muscle vascular conductance during exercise is unknown. Methods: Seven weeks of one-legged endurance training was carried out by twelve subjects. Pulmonary VO(2) during cycling and one-legged cycling was tested before and after...... training, while VO(2) of the trained leg (TL) and control leg (CL) during cycling was determined after training. Results: VO(2) max for cycling was unaffected by training, although one-legged VO(2) max became 6.7 (2.3)% (mean ± SE) larger with TL than with CL. Also TL citrate synthase activity was higher...

  3. Analysis of the body mass index and leg profiles of Asian women after total leg sculpture.

    Science.gov (United States)

    Tsai, Feng-Chou; Chen, Chien-Hao; Lin, Chan-Yi; Ho, Li-Yung

    2009-08-01

    In addition to the conventional methods used to improve leg contours, total leg sculpture, including liposuction, selective neurectomy, and transilluminated powered phlebectomy, provides a one-time solution of leg contour problems, which is a major aesthetic concern among Asian women. The authors present the postoperative results of total leg sculpture and determine any significance and correlation between the leg variables and body mass index by statistical analysis. Thirty female patients who underwent total leg sculpture between 2005 and 2008 were included in the study, and prospective analysis of the patients' data was performed during a follow-up period of 1 year. Local measurement variables and body mass index were recorded, and the correlation between them was determined by Pearson's correlation and regression analysis. A paired t test was used to compare the postoperative outcomes. Subjectively, all patient results were satisfactory. There were significant differences between preoperative and postoperative measurements for all variables for total leg sculpture. Body mass index was strongly correlated with all leg indexes, and there was a significant positive correlation between the index and variables related to the buttocks and upper thigh. The satisfactory postoperative leg variables were buttocks circumference (87.85 cm), thigh circumference (T60, 44.20 cm), maximal calf circumference (32.24 cm), and calf ratio (0.78). Each preoperative body mass index increment represents a 0.3 percent circumference improvement around the buttocks after surgery. No obvious morbidities or long-term hospital stays were noted. Total leg sculpture provides a combined aesthetic solution for improving limb contours with minimal morbidity. Patients with larger body mass index values exhibit better aesthetic improvement than those with smaller values.

  4. 49 CFR 223.17 - Identification of equipped locomotives, passenger cars and cabooses.

    Science.gov (United States)

    2010-10-01

    ... cars and cabooses. 223.17 Section 223.17 Transportation Other Regulations Relating to Transportation...-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.17 Identification of equipped locomotives, passenger cars and cabooses. Each locomotive, passenger car and caboose that is fully equipped with glazing...

  5. High performance p-type segmented leg of misfit-layered cobaltite and half-Heusler alloy

    DEFF Research Database (Denmark)

    Le, Thanh Hung; Van Nong, Ngo; Snyder, Gerald Jeffrey

    2015-01-01

    %, which is about 65% of that expected from the materials without parasitic losses. The long-term stability investigation for two weeks at the hot and cold side temperatures of 1153/397 K shows that the segmented leg has good durability as a result of stable and low electrical resistance contacts. 2015...

  6. Therapeutic advances in restless legs syndrome (RLS).

    Science.gov (United States)

    Högl, Birgit; Comella, Cynthia

    2015-09-15

    Levodopa and dopamine agonists have been the main treatment for restless legs syndrome during the past decades. Although their efficacy has been well documented over the short term, long-term dopaminergic treatment is often complicated by augmentation, loss of efficacy, and other side effects. Recent large randomized controlled trials provide new evidence for the efficacy of high-potency opioids and α2δ ligands, and several post hoc analyses, meta-analyses, algorithms, and guidelines have been published, often with a specific focus, for example, on augmentation, or on management of restless legs syndrome during pregnancy. Several new contributions to understanding the pathophysiology of restless legs syndrome have been published, but at this time, whether they will have an impact on treatment possibilities in the future cannot be estimated. © 2015 International Parkinson and Movement Disorder Society.

  7. Conjoined legs: Sirenomelia or caudal regression syndrome?

    Directory of Open Access Journals (Sweden)

    Sakti Prasad Das

    2013-01-01

    Full Text Available Presence of single umbilical persistent vitelline artery distinguishes sirenomelia from caudal regression syndrome. We report a case of a12-year-old boy who had bilateral umbilical arteries presented with fusion of both legs in the lower one third of leg. Both feet were rudimentary. The right foot had a valgus rocker-bottom deformity. All toes were present but rudimentary. The left foot showed absence of all toes. Physical examination showed left tibia vara. The chest evaluation in sitting revealed pigeon chest and elevated right shoulder. Posterior examination of the trunk showed thoracic scoliosis with convexity to right. The patient was operated and at 1 year followup the boy had two separate legs with a good aesthetic and functional results.

  8. Leg Spasticity and Ambulation in Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Swathi Balantrapu

    2014-01-01

    Full Text Available Background. Spasticity of the legs is common in multiple sclerosis (MS, but there has been limited research examining its association with ambulatory outcomes. Objective. This study examined spasticity of the legs and its association with multiple measures of ambulation in persons with MS. Methods. The sample included 84 patients with MS. Spasticity of the legs was measured using a 5-point rating scale ranging between 0 (normal and 4 (contracted. Patients completed the 6-minute walk (6 MW, timed 25 foot walk (T25FW, and timed up-and-go (TUG, and O2 cost of walking was measured during the 6 MW. The patients undertook two walking trials on a GAITRite (CIR systems, Inc. for measuring spatial and temporal parameters of gait. The patients completed the Multiple Sclerosis Walking Scale-12 (MSWS-12 and wore an accelerometer over a seven-day period. Results. 52% (n=44 of the sample presented with spasticity of the legs. Those with leg spasticity had significantly worse ambulation as measured by 6 MW (P=0.0001, d=-0.86, T25FW (P=0.003,d=0.72, TUG (P=0.001, d=0.84, MSWS-12 (P=0.0001,d=1.09, O2 cost of walking (P=0.001, d=0.75, average steps/day (P<0.05, d=-0.45, and walking velocity (P<0.05, d=-0.53 and cadence (P<0.05, d=-0.46. Conclusion. Leg spasticity was associated with impairments in ambulation, including alterations in spatiotemporal parameters and free-living walking.

  9. Small-scale soft-bodied robot with multimodal locomotion

    Science.gov (United States)

    Hu, Wenqi; Lum, Guo Zhan; Mastrangeli, Massimo; Sitti, Metin

    2018-02-01

    Untethered small-scale (from several millimetres down to a few micrometres in all dimensions) robots that can non-invasively access confined, enclosed spaces may enable applications in microfactories such as the construction of tissue scaffolds by robotic assembly, in bioengineering such as single-cell manipulation and biosensing, and in healthcare such as targeted drug delivery and minimally invasive surgery. Existing small-scale robots, however, have very limited mobility because they are unable to negotiate obstacles and changes in texture or material in unstructured environments. Of these small-scale robots, soft robots have greater potential to realize high mobility via multimodal locomotion, because such machines have higher degrees of freedom than their rigid counterparts. Here we demonstrate magneto-elastic soft millimetre-scale robots that can swim inside and on the surface of liquids, climb liquid menisci, roll and walk on solid surfaces, jump over obstacles, and crawl within narrow tunnels. These robots can transit reversibly between different liquid and solid terrains, as well as switch between locomotive modes. They can additionally execute pick-and-place and cargo-release tasks. We also present theoretical models to explain how the robots move. Like the large-scale robots that can be used to study locomotion, these soft small-scale robots could be used to study soft-bodied locomotion produced by small organisms.

  10. Using Computational and Mechanical Models to Study Animal Locomotion

    Science.gov (United States)

    Miller, Laura A.; Goldman, Daniel I.; Hedrick, Tyson L.; Tytell, Eric D.; Wang, Z. Jane; Yen, Jeannette; Alben, Silas

    2012-01-01

    Recent advances in computational methods have made realistic large-scale simulations of animal locomotion possible. This has resulted in numerous mathematical and computational studies of animal movement through fluids and over substrates with the purpose of better understanding organisms’ performance and improving the design of vehicles moving through air and water and on land. This work has also motivated the development of improved numerical methods and modeling techniques for animal locomotion that is characterized by the interactions of fluids, substrates, and structures. Despite the large body of recent work in this area, the application of mathematical and numerical methods to improve our understanding of organisms in the context of their environment and physiology has remained relatively unexplored. Nature has evolved a wide variety of fascinating mechanisms of locomotion that exploit the properties of complex materials and fluids, but only recently are the mathematical, computational, and robotic tools available to rigorously compare the relative advantages and disadvantages of different methods of locomotion in variable environments. Similarly, advances in computational physiology have only recently allowed investigators to explore how changes at the molecular, cellular, and tissue levels might lead to changes in performance at the organismal level. In this article, we highlight recent examples of how computational, mathematical, and experimental tools can be combined to ultimately answer the questions posed in one of the grand challenges in organismal biology: “Integrating living and physical systems.” PMID:22988026

  11. Decoding bipedal locomotion from the rat sensorimotor cortex

    NARCIS (Netherlands)

    Rigosa, J.; Panarese, A.; Dominici, N.; Friedli, L.; van den Brand, R.; Carpaneto, J.; DiGiovanna, J.; Courtine, G.; Micera, S.

    2015-01-01

    Objective. Decoding forelimb movements from the firing activity of cortical neurons has been interfaced with robotic and prosthetic systems to replace lost upper limb functions in humans. Despite the potential of this approach to improve locomotion and facilitate gait rehabilitation, decoding lower

  12. Locomotion and basicranial anatomy in primates and marsupials.

    Science.gov (United States)

    Villamil, Catalina I

    2017-10-01

    There is ongoing debate in paleoanthropology about whether and how the anatomy of the cranium, and especially the cranial base, is evolving in response to locomotor and postural changes. However, the majority of studies focus on two-dimensional data, which fails to capture the complexity of cranial anatomy. This study tests whether three-dimensional cranial base anatomy is linked to locomotion or to other factors in primates (n = 473) and marsupials (n = 231). Results indicate that although there is a small effect of locomotion on cranial base anatomy in primates, this is not the case in marsupials. Instead, facial anatomy likely drives variation in cranial base anatomy in both primates and marsupials, with additional roles for body size and brain size. Although some changes to foramen magnum position and orientation are phylogenetically useful among the hominoids, they do not necessarily reflect locomotion or positional behavior. The interplay between locomotion, posture, and facial anatomy in primates requires further investigation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Energetic extremes in aquatic locomotion by coral reef fishes.

    Science.gov (United States)

    Fulton, Christopher J; Johansen, Jacob L; Steffensen, John F

    2013-01-01

    Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a range of swimming vertebrates, however, has suggested that flapping paired appendages around a rigid body may be an extremely efficient means of aquatic locomotion. Using intermittent flow-through respirometry, we found exceptional energetic performance in the Bluelined wrasse Stethojulis bandanensis, which maintains tuna-like optimum cruising speeds (up to 1 metre s(-1)) while using 40% less energy than expected for their body size. Displaying an exceptional aerobic scope (22-fold above resting), streamlined rigid-body posture, and wing-like fins that generate lift-based thrust, S. bandanensis literally flies underwater to efficiently maintain high optimum swimming speeds. Extreme energetic performance may be key to the colonization of highly variable environments, such as the wave-swept habitats where S. bandanensis and other wing-finned species tend to occur. Challenging preconceived notions of how best to power aquatic locomotion, biomimicry of such lift-based fin movements could yield dramatic reductions in the power needed to propel underwater vehicles at high speed.

  14. Energetic extremes in aquatic locomotion by coral reef fishes.

    Directory of Open Access Journals (Sweden)

    Christopher J Fulton

    Full Text Available Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a range of swimming vertebrates, however, has suggested that flapping paired appendages around a rigid body may be an extremely efficient means of aquatic locomotion. Using intermittent flow-through respirometry, we found exceptional energetic performance in the Bluelined wrasse Stethojulis bandanensis, which maintains tuna-like optimum cruising speeds (up to 1 metre s(-1 while using 40% less energy than expected for their body size. Displaying an exceptional aerobic scope (22-fold above resting, streamlined rigid-body posture, and wing-like fins that generate lift-based thrust, S. bandanensis literally flies underwater to efficiently maintain high optimum swimming speeds. Extreme energetic performance may be key to the colonization of highly variable environments, such as the wave-swept habitats where S. bandanensis and other wing-finned species tend to occur. Challenging preconceived notions of how best to power aquatic locomotion, biomimicry of such lift-based fin movements could yield dramatic reductions in the power needed to propel underwater vehicles at high speed.

  15. Dynamics and locomotion of flexible foils in a frictional environment

    Science.gov (United States)

    Wang, Xiaolin; Alben, Silas

    2018-01-01

    Over the past few decades, oscillating flexible foils have been used to study the physics of organismal propulsion in different fluid environments. Here, we extend this work to a study of flexible foils in a frictional environment. When the foil is oscillated by heaving at one end but is not free to locomote, the dynamics change from periodic to non-periodic and chaotic as the heaving amplitude increases or the bending rigidity decreases. For friction coefficients lying in a certain range, the transition passes through a sequence of N-periodic and asymmetric states before reaching chaotic dynamics. Resonant peaks are damped and shifted by friction and large heaving amplitudes, leading to bistable states. When the foil is free to locomote, the horizontal motion smoothes the resonant behaviours. For moderate frictional coefficients, steady but slow locomotion is obtained. For large transverse friction and small tangential friction corresponding to wheeled snake robots, faster locomotion is obtained. Travelling wave motions arise spontaneously, and move with horizontal speeds that scale as transverse friction coefficient to the power 1/4 and input power that scales as the transverse friction coefficient to the power 5/12. These scalings are consistent with a boundary layer form of the solutions near the foil's leading edge.

  16. 49 CFR 231.30 - Locomotives used in switching service.

    Science.gov (United States)

    2010-10-01

    ... classification of cars according to commodity or destination; assembling of cars for train movements; changing... locomotives built after March 31, 1977. (5) Material. (i) Steel or other material of equivalent or better... March 31, 1977, each vertical handhold must— (i) Be constructed of wrought iron, steel or other material...

  17. Energetic Extremes in Aquatic Locomotion by Coral Reef Fishes

    Science.gov (United States)

    Fulton, Christopher J.; Johansen, Jacob L.; Steffensen, John F.

    2013-01-01

    Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a range of swimming vertebrates, however, has suggested that flapping paired appendages around a rigid body may be an extremely efficient means of aquatic locomotion. Using intermittent flow-through respirometry, we found exceptional energetic performance in the Bluelined wrasse Stethojulis bandanensis, which maintains tuna-like optimum cruising speeds (up to 1 metre s−1) while using 40% less energy than expected for their body size. Displaying an exceptional aerobic scope (22-fold above resting), streamlined rigid-body posture, and wing-like fins that generate lift-based thrust, S. bandanensis literally flies underwater to efficiently maintain high optimum swimming speeds. Extreme energetic performance may be key to the colonization of highly variable environments, such as the wave-swept habitats where S. bandanensis and other wing-finned species tend to occur. Challenging preconceived notions of how best to power aquatic locomotion, biomimicry of such lift-based fin movements could yield dramatic reductions in the power needed to propel underwater vehicles at high speed. PMID:23326566

  18. Application of flywheel energy storage for heavy haul locomotives

    International Nuclear Information System (INIS)

    Spiryagin, Maksym; Wolfs, Peter; Szanto, Frank; Sun, Yan Quan; Cole, Colin; Nielsen, Dwayne

    2015-01-01

    Highlights: • A novel design for heavy haul locomotive equipped with a flywheel energy storage system is proposed. • The integrated intelligent traction control system was developed. • A flywheel energy storage system has been tested through a simulation process. • The developed hybrid system was verified using an existing heavy haul railway route. • Fuel efficiency analysis confirms advantages of the hybrid design. - Abstract: At the present time, trains in heavy haul operations are typically hauled by several diesel-electric locomotives coupled in a multiple unit. This paper studies the case of a typical consist of three Co–Co diesel-electric locomotives, and considers replacing one unit with an alternative version, with the same design parameters, except that the diesel-electric plant is replaced with flywheel energy storage equipment. The intelligent traction and energy control system installed in this unit is integrated into the multiple-unit control to allow redistribution of the power between all units. In order to verify the proposed design, a three-stage investigation has been performed as described in this paper. The initial stage studies a possible configuration of the flywheel energy storage system by detailed modelling of the proposed intelligent traction and energy control system. The second stage includes the investigation and estimation of possible energy flows using a longitudinal train dynamics simulation. The final stage compares the conventional and the proposed locomotive configurations considering two parameters: fuel efficiency and emissions reduction.

  19. Physical fitness, nutritional habits and daily locomotive action of 12 ...

    African Journals Online (AJOL)

    Objective. The purpose of this study was to examine the differences in physical fitness, daily nutritional habits and locomotive behaviour among pupils with varying body mass index (BMI) in the 5th and 6th grades of primary school. Design. The sample consisted of 480 pupils (229 boys and 251 girls), who participated in ...

  20. Transmembrane channel-like (tmc) gene regulates Drosophila larval locomotion.

    Science.gov (United States)

    Guo, Yanmeng; Wang, Yuping; Zhang, Wei; Meltzer, Shan; Zanini, Damiano; Yu, Yue; Li, Jiefu; Cheng, Tong; Guo, Zhenhao; Wang, Qingxiu; Jacobs, Julie S; Sharma, Yashoda; Eberl, Daniel F; Göpfert, Martin C; Jan, Lily Yeh; Jan, Yuh Nung; Wang, Zuoren

    2016-06-28

    Drosophila larval locomotion, which entails rhythmic body contractions, is controlled by sensory feedback from proprioceptors. The molecular mechanisms mediating this feedback are little understood. By using genetic knock-in and immunostaining, we found that the Drosophila melanogaster transmembrane channel-like (tmc) gene is expressed in the larval class I and class II dendritic arborization (da) neurons and bipolar dendrite (bd) neurons, both of which are known to provide sensory feedback for larval locomotion. Larvae with knockdown or loss of tmc function displayed reduced crawling speeds, increased head cast frequencies, and enhanced backward locomotion. Expressing Drosophila TMC or mammalian TMC1 and/or TMC2 in the tmc-positive neurons rescued these mutant phenotypes. Bending of the larval body activated the tmc-positive neurons, and in tmc mutants this bending response was impaired. This implicates TMC's roles in Drosophila proprioception and the sensory control of larval locomotion. It also provides evidence for a functional conservation between Drosophila and mammalian TMCs.

  1. Neurovascular coupling and decoupling in the cortex during voluntary locomotion.

    Science.gov (United States)

    Huo, Bing-Xing; Smith, Jared B; Drew, Patrick J

    2014-08-13

    Hemodynamic signals are widely used to infer neural activity in the brain. We tested the hypothesis that hemodynamic signals faithfully report neural activity during voluntary behaviors by measuring cerebral blood volume (CBV) and neural activity in the somatosensory cortex and frontal cortex of head-fixed mice during locomotion. Locomotion induced a large and robust increase in firing rate and gamma-band (40-100 Hz) power in the local field potential in the limb representations in somatosensory cortex, and was accompanied by increases in CBV, demonstrating that hemodynamic signals are coupled with neural activity in this region. However, in the frontal cortex, CBV did not change during locomotion, but firing rate and gamma-band power both increased, indicating a decoupling of neural activity from the hemodynamic signal. These results show that hemodynamic signals are not faithful indicators of the mean neural activity in the frontal cortex during locomotion; thus, the results from fMRI and other hemodynamic imaging methodologies for studying neural processes must be interpreted with caution. Copyright © 2014 the authors 0270-6474/14/3410975-07$15.00/0.

  2. Locomotion in Stroke Subjects: Interactions between Unaffected and Affected Sides

    Science.gov (United States)

    Kloter, Evelyne; Wirz, Markus; Dietz, Volker

    2011-01-01

    The aim of this study was to evaluate the sensorimotor interactions between unaffected and affected sides of post-stroke subjects during locomotion. In healthy subjects, stimulation of the tibial nerve during the mid-stance phase is followed by electromyography responses not only in the ipsilateral tibialis anterior, but also in the proximal arm…

  3. Using Jacqueline Woodson's "Locomotion" with Middle School Readers

    Science.gov (United States)

    Napoli, Mary; Ritholz, Emily Rose

    2009-01-01

    Motivation is an essential component in developing a love of reading in middle level struggling students. For these readers, novels in verse bridge the gap to more challenging pieces of literature. In this article, Title One students explored Locomotion by Jacqueline Woodson and learned that they, too, are poets. (Contains 9 figures.)

  4. A Method for Locomotion Mode Identification Using Muscle Synergies.

    Science.gov (United States)

    Afzal, Taimoor; Iqbal, Kamran; White, Gannon; Wright, Andrew B

    2017-06-01

    Active lower limb transfemoral prostheses have enabled amputees to perform different locomotion modes such as walking, stair ascent, stair descent, ramp ascent and ramp descent. To achieve seamless mode transitions, these devices either rely on neural information from the amputee's residual limbs or sensors attached to the prosthesis to identify the intended locomotion modes or both. We present an approach for classification of locomotion modes based on the framework of muscle synergies underlying electromyography signals. Neural information at the critical instances (e.g., heel contact and toe-off) was decoded for this purpose. Non-negative matrix factorization was used to extract the muscles synergies from the muscle feature matrix. The estimation of the neural command was done using non-negative least squares. The muscle synergy approach was compared with linear discriminant analysis (LDA), support vector machine (SVM), and neural network (NN) and was tested on seven able-bodied subjects. There was no significant difference ( p > 0.05 ) in transitional and steady state classification errors during stance phase. The muscle synergy approach performed significantly better ( ) than NN and LDA during swing phase while results were similar to SVM. These results suggest that the muscle synergy approach can be used to discriminate between locomotion modes involving transitions.

  5. Tractable Quantification of Metastability for Robust Bipedal Locomotion

    Science.gov (United States)

    2015-06-01

    Mathematics GPA 4.0/4.0 2007-2011 Sabanci University, Istanbul B.S. in Mechatronics Engineering Minor in Mathematics GPA 3.88/4.0 Major GPA: 3.96/4.00...on Mechatronics (ICM), pages 997-1002, April 2011. viii Abstract Tractable Quantification of Metastability for Robust Bipedal Locomotion by Cenk Oguz

  6. Using computational and mechanical models to study animal locomotion.

    Science.gov (United States)

    Miller, Laura A; Goldman, Daniel I; Hedrick, Tyson L; Tytell, Eric D; Wang, Z Jane; Yen, Jeannette; Alben, Silas

    2012-11-01

    Recent advances in computational methods have made realistic large-scale simulations of animal locomotion possible. This has resulted in numerous mathematical and computational studies of animal movement through fluids and over substrates with the purpose of better understanding organisms' performance and improving the design of vehicles moving through air and water and on land. This work has also motivated the development of improved numerical methods and modeling techniques for animal locomotion that is characterized by the interactions of fluids, substrates, and structures. Despite the large body of recent work in this area, the application of mathematical and numerical methods to improve our understanding of organisms in the context of their environment and physiology has remained relatively unexplored. Nature has evolved a wide variety of fascinating mechanisms of locomotion that exploit the properties of complex materials and fluids, but only recently are the mathematical, computational, and robotic tools available to rigorously compare the relative advantages and disadvantages of different methods of locomotion in variable environments. Similarly, advances in computational physiology have only recently allowed investigators to explore how changes at the molecular, cellular, and tissue levels might lead to changes in performance at the organismal level. In this article, we highlight recent examples of how computational, mathematical, and experimental tools can be combined to ultimately answer the questions posed in one of the grand challenges in organismal biology: "Integrating living and physical systems."

  7. The Molecular Genetics of Restless Legs Syndrome.

    Science.gov (United States)

    Rye, David B

    2015-09-01

    Restless legs syndrome (RLS) is a common sensorimotor trait defined by symptoms that interfere with sleep onset and maintenance in a clinically meaningful way. Nonvolitional myoclonus while awake and asleep is a sign of the disorder and an informative endophenotype. The genetic contributions to RLS/periodic leg movements are substantial, are among the most robust defined to date for a common disease, and account for much of the variance in disease expressivity. The disorder is polygenic, as revealed by recent genome-wide association studies. Experimental studies are revealing mechanistic details of how these common variants might influence RLS expressivity. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Nocturnal leg cramps in older people

    Science.gov (United States)

    Butler, J; Mulkerrin, E; O'Keeffe, S

    2002-01-01

    Nocturnal leg cramps are common in older people. Such cramps are associated with many common diseases and medications. Physiological methods may be useful for preventing cramps in some people, but there have been no controlled trials of these approaches. Quinine is moderately effective in preventing nocturnal leg cramps. However, there are concerns about the risk/benefit ratio with this drug. In patients with severe symptoms, a trial of 4–6 weeks' treatment with quinine is probably still justified, but the efficacy of treatment should be monitored, for example using a sleep and cramp diary. PMID:12415081

  9. Symptom Severity of Restless Legs Syndrome Predicts Its Clinical Course.

    Science.gov (United States)

    Lee, Chung Suk; Kim, Tae; Lee, Sumin; Jeon, Hong Jun; Bang, Young Rong; Yoon, In-Young

    2016-04-01

    This study examines the clinical course of restless legs syndrome according to its severity and factors associated with the remission of restless legs syndrome symptoms. The remission or persistence of restless legs syndrome symptoms was investigated by considering patients with restless legs syndrome at the sleep clinic of Seoul National University Bundang Hospital. All subjects were observed for at least 18 months, and an incidence of remission was defined as having no restless legs syndrome symptoms for at least 1 year. Restless legs syndrome severity was evaluated by the International Restless Legs Syndrome Study Group Rating Scale. A total of 306 patients participated in this study. Over the observation periods of 4.1 ± 1.6 years, the cumulative incidence of remission is 32.5% (95% confidence interval [CI], 27.0-38.0) and decreased with baseline restless legs syndrome severity (P restless legs syndrome cases, respectively. Most cases of remission (82/96) were observed within 1 year, and the remission occurred sooner for mild restless legs syndrome. The hazard ratios of remission by Cox proportional hazards model were lower for moderate (0.556; 95% CI, 0.340-0.909) and severe to very severe (0.193; 95% CI, 0.108-0.343) restless legs syndrome than for mild restless legs syndrome. The remission incidence was lower for those patients who had a family history of restless legs syndrome and were older at restless legs syndrome diagnosis. Mild restless legs syndrome severity, no family history, and young age at restless legs syndrome diagnosis were significant predictors of restless legs syndrome remission. More than 80% of patients with severe restless legs syndrome showed a chronic clinical course. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. A crawling robot driven by multi-stable origami

    Science.gov (United States)

    Pagano, Alexander; Yan, Tongxi; Chien, Brian; Wissa, A.; Tawfick, S.

    2017-09-01

    Using origami folding to construct and actuate mechanisms and machines offers attractive opportunities from small, scalable, and cheap robots to deployable adaptive structures. This paper presents the design of a bio-inspired origami crawling robot constructed by folding sheets of paper. The origami building block structure is based on the Kresling crease pattern (CP), a chiral tower with a polygonal base, which expands and contracts through coupled longitudinal and rotational motion similar to a screw. We design the origami to have multi-stable structural equilibria which can be tuned by changing the folding CP. Kinematic analysis of these structures based on rigid-plates and hinges at fold lines precludes the shape transformation associated with the bistability of the physical models. To capture the kinematics of the bi-stable origami, the panels’ deformation behavior is modeled utilizing principles of virtual folds. Virtual folds approximate material bending by hinged, rigid panels, which facilitates the development of a kinematic solution via rigid-plate rotation analysis. As such, the kinetics and stability of folded structures are investigated by assigning suitable torsional spring constants to the fold lines. The results presented demonstrate the effect of fold-pattern geometries on the snapping behavior of the bi-stable origami structure based on the Kresling pattern. The crawling robot is presented as a case study for the use of this origami structure to mimic crawling locomotion. The robot is comprised of two origami towers nested inside a paper bellow, and connected by 3D printed end plates. DC motors are used to actuate the expansion and contraction of the internal origami structures to achieve forward locomotion and steering. Beyond locomotion, this simple design can find applications in manipulators, booms, and active structures.

  11. THE EFFECTS OF SINGLE LEG HOP PROGRESSION AND DOUBLE LEGS HOP PROGRESSION EXERCISE TO INCREASE SPEED AND EXPLOSIVE POWER OF LEG MUSCLE

    Directory of Open Access Journals (Sweden)

    Nining W. Kusnanik

    2015-05-01

    Full Text Available The main purpose of this study was to determine the effect of single leg hop progression and double legs hop progression exercise to increase speed and explosive power of leg muscles. Plyometric is one of the training methods that can increase explosive power. There are many models of plyometric training including single leg hop progression and double leg hop progression. This research was experimental using match subject design techniques. The subjects of this study were 39 students who joined basketball school club. There were 3 groups in this study: Group 1 were 13 students who given sin¬gle leg hop progression exercise, Group 2 were 13 students who given double legs hop progression exercise, Group 3 were 13 students who given conventional exercise. The data was collected during pre test and post test by testing 30m speed running and vertical jump. The data was analyzed using Analysis of Varians (Anova. It was found that there were significantly increased on speed and explosive power of leg muscles of Group 1 and Group 2. It can be stated that single leg hop progression exercise was more effective than double leg hop progression exercise. The recent findings supported the hypothesis that single leg hop progression and double legs hop progression exercise can increase speed and explosive power of leg muscles. These finding were supported by some previous studies (Singh, et al, 2011; Shallaby, H.K., 2010. The single leg hop progression is more effective than double legs hop progression. This finding was consistent with some previous evidences (McCurdy, et al, 2005; Makaruk et al, 2011.

  12. stableGP

    Data.gov (United States)

    National Aeronautics and Space Administration — The code in the stableGP package implements Gaussian process calculations using efficient and numerically stable algorithms. Description of the algorithms is in the...

  13. Clinical characteristics of leg restlessness in Parkinson's disease compared with idiopathic Restless Legs Syndrome.

    Science.gov (United States)

    Zhu, Xiao-Ying; Liu, Ye; Zhang, Xiao-Jin; Yang, Wen-Hao; Feng, Ya; Ondo, William G; Tan, Eng-King; Wu, Yun-Cheng

    2015-10-15

    There is limited data on motor restlessness in Parkinson's disease (PD). Here we evaluate for clinical differences between cohorts of idiopathic Restless Legs Syndrome (iRLS), PD patients with leg restlessness, and PD with RLS. We examined 276 consecutive PD patients for leg restlessness symptoms, we compared clinical features of PD patients with RLS, PD patients with leg restlessness but not meeting RLS criteria, PD patient without RLS and iRLS. A total of 262 PD patients who satisfied the inclusion criteria were analyzed. After excluding 23 possible secondary RLS or mimics, 28 were diagnosed with RLS and 18 with leg motor restlessness (LMR). Compared with iRLS patients, PD patients with RLS or LMR had older age of RLS/LMR onset, shorter duration of leg restlessness, less positive family history, different seasonal trends and more unilaterality of leg restlessness symptom (Pleg restlessness. PD with LMR had less severe Parkinsonism (Pleg restlessness (P<0.01) symptoms than PD with RLS. Clinical characteristics of PD patients with RLS and LMR were different from iRLS, differentiating these various subtypes can facilitate optimal treatment. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Origami-based earthworm-like locomotion robots.

    Science.gov (United States)

    Fang, Hongbin; Zhang, Yetong; Wang, K W

    2017-10-16

    Inspired by the morphology characteristics of the earthworms and the excellent deformability of origami structures, this research creates a novel earthworm-like locomotion robot through exploiting the origami techniques. In this innovation, appropriate actuation mechanisms are incorporated with origami ball structures into the earthworm-like robot 'body', and the earthworm's locomotion mechanism is mimicked to develop a gait generator as the robot 'centralized controller'. The origami ball, which is a periodic repetition of waterbomb units, could output significant bidirectional (axial and radial) deformations in an antagonistic way similar to the earthworm's body segment. Such bidirectional deformability can be strategically programmed by designing the number of constituent units. Experiments also indicate that the origami ball possesses two outstanding mechanical properties that are beneficial to robot development: one is the structural multistability in the axil direction that could contribute to the robot control implementation; and the other is the structural compliance in the radial direction that would increase the robot robustness and applicability. To validate the origami-based innovation, this research designs and constructs three robot segments based on different axial actuators: DC-motor, shape-memory-alloy springs, and pneumatic balloon. Performance evaluations reveal their merits and limitations, and to prove the concept, the DC-motor actuation is selected for building a six-segment robot prototype. Learning from earthworms' fundamental locomotion mechanism-retrograde peristalsis wave, seven gaits are automatically generated; controlled by which, the robot could achieve effective locomotion with qualitatively different modes and a wide range of average speeds. The outcomes of this research could lead to the development of origami locomotion robots with low fabrication costs, high customizability, light weight, good scalability, and excellent re-configurability.

  15. Altered control strategy between leading and trailing leg increases knee adduction moment in the elderly while descending stairs.

    Science.gov (United States)

    Karamanidis, Kiros; Arampatzis, Adamantios

    2011-02-24

    The aim of the study was to examine the external knee adduction moments in a group of older and younger adults while descending stairs and thus the possibility of an increased risk of knee osteoarthritis due to altered knee joint loading in the elderly. Twenty-seven older and 16 younger adults descended a purpose-built staircase. A motion capture system and a force plate were used to determine the subjects' 3D kinematics and ground reaction forces (GRF) during locomotion. Calculation of the leg kinematics and kinetics was done by means of a rigid, three-segment, 3D leg model. In the initial portion of the support phase, older adults showed a more medio-posterior GRF vector relative to the ankle joint, leading to lower ankle joint moments (Pelderly (Pcontrol strategy while stepping down is a more medially directed GRF vector increasing the magnitude of external knee adduction moment in the elderly. The observed changes between leading and trailing leg in the elderly may cause a redistribution of the mechanical load at the tibiofemoral joint, affecting the initiation and progression of knee osteoarthritis in the elderly. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. [The influence of the leg load and the support mobility under leg on the anticipatory postural adjustment].

    Science.gov (United States)

    Kazennikov, O V; Kireeva, T B; Shlykov, V Iu

    2015-01-01

    Anticipatory postural adjustment is an essential part of equilibrium maintainance during standing in human. So changes in stance condition could affect both control of equilibrium and anticipatory adjustment. Anticipatory changes in the stabilogram of each leg were studied in standing subject during the early stage of quick right arm lifting while legs were on two separated supports. The center of pressure (CP) movement was analyzed in three variants of experiment: both legs on immovable support, with only right leg on the movable support and with only left leg on the moveable support. In each standing condition subject stood with symmetrical load on two legs or with the load voluntary transferred to one leg. The anticipatory CP shift depended on the mobility of the support under the leg and on loading of the leg. While standing on unmovable supports with symmetrical load on the legs before lifting of the right arm CP of right leg shifted backward and CP of left leg--forward. While standing with one leg on movable support the anticipatory CP shift of this leg was small and did not depend on the load on the leg. However the shift of CP of the leg that was placed on the unmovable support depended on the load in the same way as in the case when both legs were on unmovable supports. Results suggested that since on movable support the support and proprioceptive afferent flow from distal part of the leg that was did not supply unambiguous information about body position, the role of distal joints in posture control is reduced.

  17. A locomotion intent prediction system based on multi-sensor fusion.

    Science.gov (United States)

    Chen, Baojun; Zheng, Enhao; Wang, Qining

    2014-07-10

    Locomotion intent prediction is essential for the control of powered lower-limb prostheses to realize smooth locomotion transitions. In this research, we develop a multi-sensor fusion based locomotion intent prediction system, which can recognize current locomotion mode and detect locomotion transitions in advance. Seven able-bodied subjects were recruited for this research. Signals from two foot pressure insoles and three inertial measurement units (one on the thigh, one on the shank and the other on the foot) are measured. A two-level recognition strategy is used for the recognition with linear discriminate classifier. Six kinds of locomotion modes and ten kinds of locomotion transitions are tested in this study. Recognition accuracy during steady locomotion periods (i.e., no locomotion transitions) is 99.71% ± 0.05% for seven able-bodied subjects. During locomotion transition periods, all the transitions are correctly detected and most of them can be detected before transiting to new locomotion modes. No significant deterioration in recognition performance is observed in the following five hours after the system is trained, and small number of experiment trials are required to train reliable classifiers.

  18. An automatic hinge system for leg orthoses

    NARCIS (Netherlands)

    Rietman, J. S.; Goudsmit, J.; Meulemans, D.; Halbertsma, J. P. K.; Geertzen, J. H. B.

    2004-01-01

    This paper describes a new automatic hinge system for leg orthoses, which provides knee stability in stance, and allows knee-flexion during swing. Indications for the hinge system are a paresis or paralysis of the quadriceps muscles. Instrumented gait analysis was performed in three patients, fitted

  19. An automatic hinge system for leg orthoses

    NARCIS (Netherlands)

    Rietman, J.S.; Goudsmit, J.; Meulemans, D.; Halbertsma, J.P.K.; Geertzen, J.H.B.

    This paper describes a new, automatic hinge system for leg orthoses, which provides knee stability in stance, and allows knee-flexion during swing. Indications for the hinge system are a paresis or paralysis of the quadriceps muscles. Instrumented gait analysis was performed in three patients,

  20. Chronic leg ulcer caused by Mycobacterium immunogenum

    NARCIS (Netherlands)

    Loots, Miriam A. M.; de Jong, Menno D.; van Soolingen, Dick; Wetsteyn, José C. F. M.; Faber, William R.

    2005-01-01

    Rare tropical skin diseases are seen more frequently in Western countries because of the increased popularity of visiting tropical regions. A 55-year-old white man developed a painless leg ulcer after traveling in Guatemala and Belize. A mycobacterium was cultured from a biopsy specimen and was

  1. X-Ray Exam: Femur (Upper Leg)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español X-Ray Exam: Femur (Upper Leg) KidsHealth / For Parents / X- ... Muscles, and Joints Broken Bones Getting an X-ray (Video) X-Ray (Video) View more Partner Message About Us ...

  2. The restless legs syndrome (Ekbom's syndrome)

    African Journals Online (AJOL)

    1983-04-30

    Apr 30, 1983 ... same distribution as the paraesthesiae; and (v) anxiety, tension or mild depression. Paraesthesiae or creeping sensations are usually confined to the calves. They are extremely unpleasant and deep-seated in muscles or bones rather than in the skin, mostly affecting the legs between the knee and ankle.

  3. Leg og læring

    DEFF Research Database (Denmark)

    Pedersen, Annette

    2008-01-01

    Leg synes at have et potentiale som metode til at fremme læring. Men hvordan? Legen har en vis grad af parallelitet med den virkelige verden i dens interaktive og relationelle strukturer. Det bliver muligt at finde nye meninger i interaktioner, som refererer til vante interaktionsformer, men...

  4. Functional scoliosis caused by leg length discrepancy

    Science.gov (United States)

    Daniszewska, Barbara; Zolynski, Krystian

    2010-01-01

    Introduction Leg length discrepancy (LLD) causes pelvic obliquity in the frontal plane and lumbar scoliosis with convexity towards the shorter extremity. Leg length discrepancy is observed in 3-15% of the population. Unequalized lower limb length discrepancy leads to posture deformation, gait asymmetry, low back pain and discopathy. Material and methods In the years 1998-2006, 369 children, aged 5 to 17 years (209 girls, 160 boys) with LLD-related functional scoliosis were treated. An external or internal shoe lift was applied. Results Among 369 children the discrepancy of 0.5 cm was observed in 27, 1 cm in 329, 1.5 cm in 9 and 2 cm in 4 children. During the first follow-up examination, within 2 weeks, the adjustment of the spine to new static conditions was noted and correction of the curve in 316 examined children (83.7%). In 53 children (14.7%) the correction was observed later and was accompanied by slight low back pain. The time needed for real equalization of limbs was 3 to 24 months. The time needed for real equalization of the discrepancy was 11.3 months. Conclusions Leg length discrepancy equalization results in elimination of scoliosis. Leg length discrepancy < 2 cm is a static disorder; that is why measurements should be performed in a standing position using blocks of adequate thickness and the position of the posterior superior iliac spine should be estimated. PMID:22371777

  5. Parallel kinematics robot with five legs

    NARCIS (Netherlands)

    Lambert, P.

    2011-01-01

    Robot with multiple degrees of freedom comprising five legs (2) linked at a first of their ends to a base ( 3), and at a second of their ends opposite to the first ends to a mobile platform (4), which platform carries at least one tool (5, 6, 121, 12 "), and wherein the robot further comprises an

  6. Energy-based control for a biologically inspired hexapod robot with rolling locomotion

    Directory of Open Access Journals (Sweden)

    Takuma Nemoto

    2015-04-01

    Full Text Available This paper presents an approach to control rolling locomotion on the level ground with a biologically inspired hexapod robot. For controlling rolling locomotion, a controller which can compensate energy loss with rolling locomotion of the hexapod robot is designed based on its dynamic model. The dynamic model describes the rolling locomotion which is limited to planar one by an assumption that the hexapod robot does not fall down while rolling and influences due to collision and contact with the ground, and it is applied for computing the mechanical energy of the hexapod robot and a plant for a numerical simulation. The numerical simulation of the rolling locomotion on the level ground verifies the effectiveness of the proposed controller. The simulation results show that the hexapod robot can perform the rolling locomotion with the proposed controller. In conclusion, it is shown that the proposed control approach is effective in achieving the rolling locomotion on the level ground.

  7. Electric-Pneumatic Actuator: A New Muscle for Locomotion

    OpenAIRE

    Ahmad Sharbafi, Maziar; Shin, Hirofumi; Zhao, Guoping; Hosoda, Koh; Seyfarth, Andre

    2017-01-01

    A better understanding of how actuator design supports locomotor function may help develop novel and more functional powered assistive devices or robotic legged systems. Legged robots comprise passive parts (e.g., segments, joints and connections) which are moved in a coordinated manner by actuators. In this study, we propose a novel concept of a hybrid electric-pneumatic actuator (EPA) as an enhanced variable impedance actuator (VIA). EPA is consisted of a pneumatic artificial muscle (PAM) a...

  8. The Role of Complex Treatment in Mixed Leg Ulcers – A Case Report of Vascular, Surgical and Physical Therapy

    Science.gov (United States)

    Wollina, Uwe; Heinig, Birgit; Stelzner, Christian; Hansel, Gesina; Schönlebe, Jacqueline; Tchernev, Georgi; Lotti, Torello

    2018-01-01

    BACKGROUND: Leg ulcers are a burden to patients, their families and society. The second most common cause of chronic leg ulcers is the mixed arterio-venous type. An 80-year-old female patient presented to our department due to painful enlarging chronic leg ulcer of mixed arteriovenous origin on her left lower leg. She suffered from peripheral arterial occlusive disease stage I and chronic venous insufficiency Widmer grade IIIa, and a number of comorbidities. AIM: The aim of our ulcer treatment was a complete and stable wound closure that was hampered by arterial occlusion, exposed tendon, and renal insiffuciency. CASE REPORT: To improve the prognosis for ulcer surgery, we performed percutaneous transluminal angioplasty, transcutaneous CO2 and deep ulcer shaving. The wound was closed by sandwich transplantation using elastin-collagen dermal template and meshed split skin graft. She had a 100% graft take with rapid reduction of severe wound pain. CONCLUSION: Complex approaches are necessary, to gain optimum results in leg ulcer therapy in mixed leg ulcers. Therapeutic nihilism should be abandonend. PMID:29483986

  9. ANALYSIS OF THE OPERATIONAL CHARACTERISTICS OF DIESEL-ELECTRIC LOCOMOTIVES

    Directory of Open Access Journals (Sweden)

    L. V. Ursulyak

    2014-12-01

    Full Text Available Purpose. To compare the operational characteristics of freight diesel-electric locomotives ER20CF and 2М62м, which are operated with Lithuanian Railways. Important problems on traction calculations are considered in this article. In this article the critical tasks of traction calculations are solved. It is the main computational tool in the rational functioning, planning and development of railways: determination of the estimated weight of the rolling stock, the diagrams construction of specific resultant forces of a train, the permitted speed definition of the train on the slopes, curves of train traffic construction on the section. Methodology. Using the rules and methods of traction calculations the analysis of the basic operational characteristics of the modernized freight diesel-electric locomotive 2М62m and freight passenger dual locomotive 2ER20CF was held. The maximum weight of the train set, the track structure on a high-speed ascent through the use of kinetic energy (with traction and without traction, technical speed, acceleration force and the value of the smallest radius curve are selected as controlled parameters. During the calculations it was considered that the trains were formed of a fully loaded four-axle gondola cars, model 112-119 (feature-606 with axle load of 23.5 t; the motion was carried out on the continuous welded rail track; the front of the train set is a dual locomotive 2ER20CF or two locomotive 2М62м. Longitudinal profile of the road on the route Vilnus–KlF was analyzed for the choice of theoretical rise. Inspection concerning the possibility of overcoming the high-speed rise was performed with an analytical method, based on the use of the kinetic energy accumulated by the overcoming of «light» elements of the profile. Findings. In the calculations, the maximum weight of the train set taking into account theoretical rise was analyzed. The inspection of the theoretical weight of the train set on a reliable

  10. Interventions for leg cramps in pregnancy.

    Science.gov (United States)

    Zhou, Kunyan; West, Helen M; Zhang, Jing; Xu, Liangzhi; Li, Wenjuan

    2015-08-11

    Leg cramps are a common problem in pregnancy. Various interventions have been used to treat them, including drug, electrolyte and vitamin therapies, and non-drug therapies. To assess the effectiveness and safety of different interventions for treating leg cramps in pregnancy. We searched the Cochrane Pregnancy and Childbirth Group's Register (31 March 2015) and reference lists of retrieved studies. Randomised controlled trials (RCTs) of any intervention (drug, electrolyte, vitamin or non-drug therapies) for treatment of leg cramps in pregnancy compared with placebo, no treatment or other treatment. Quinine was excluded for its known adverse effects (teratogenicity). Cluster-RCTS were considered for inclusion. Quasi-RCTs and cross-over studies were excluded. Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We included six studies (390 women). Four trials compared oral magnesium with placebo/no treatment, two compared oral calcium with no treatment, one compared oral vitamin B versus no treatment, and one compared oral calcium with oral vitamin C. Two of the trials were well-conducted and reported, the other four had design limitations. The process of random allocation was sub-optimal in three studies, and blinding was not attempted in two. Outcomes were reported in different ways, precluding the use of meta-analysis and limiting the strength of our conclusions.The 'no treatment' group in one four-arm trial has been used as the comparison group for the composite outcome (intensity and frequency of leg cramps) in magnesium, calcium, and vitamin B versus no treatment. This gives it disproportionate weight in the overall analysis, thus interpretation of these results should be cautious. Oral magnesium versus placebo/no treatmentMagnesium (taken orally for two to four weeks) did not consistently reduce the frequency of leg cramps compared with placebo or no treatment. Outcomes that showed

  11. A gas chromatographic method for the identification of gamma-irradiated frog legs

    International Nuclear Information System (INIS)

    Morehouse, K.M.; Yuoh Ku

    1990-01-01

    When triglycerides or fatty acids are irradiated, some of the major stable products formed are hydrocarbons with one less carbon than the parent fatty acids. These hydrocarbons are formed as the result of the loss of CO 2 via various free radical reactions. A procedure has been developed utilizing capillary gas chromatography (GC) to monitor the formation of these hydrocarbons in gamma-irradiated frog legs. Since frog legs contain large amounts of palmitic, stearic, oleic, and linoleic acids, the formation of the hydrocarbons (pentadecane, heptadecane, 8-heptadecene, and 6,9-heptadecadiene, respectively) from the decarboxylation of these fatty acids was monitored. The yield of these hydrocarbons was found to be linear with applied dose. A sample from a lot of imported frog legs that were believed to have been irradiated was also analyzed. The results obtained from the GC determination of the hydrocarbons compared favorably with those obtained by using electron spin resonance to monitor the free radicals trapped in the frog leg bone after irradiation. (author)

  12. Leg power among malaysian netball players | Geok | African Journal ...

    African Journals Online (AJOL)

    The purpose of the study was to compare the leg power among Malaysian national netball players according to their age and playing position. The Vertical Jump Test was chosen to measure the leg power by using “Digital Indication Jump Meter” device. The results of the Vertical Jump Test were used to compare the leg ...

  13. Protection against high intravascular pressure in giraffe legs

    DEFF Research Database (Denmark)

    Petersen, Karin K; Hørlyck, Arne; Østergaard, Kristine Hovkjær

    2013-01-01

    The high blood pressure in giraffe leg arteries renders giraffes vulnerable to edema. We investigated in 11 giraffes whether large and small arteries in the legs and the tight fascia protect leg capillaries. Ultrasound imaging of foreleg arteries in anesthetized giraffes and ex vivo examination...

  14. Spinal corollary discharge modulates motion sensing during vertebrate locomotion.

    Science.gov (United States)

    Chagnaud, Boris P; Banchi, Roberto; Simmers, John; Straka, Hans

    2015-09-04

    During active movements, neural replicas of the underlying motor commands may assist in adapting motion-detecting sensory systems to an animal's own behaviour. The transmission of such motor efference copies to the mechanosensory periphery offers a potential predictive substrate for diminishing sensory responsiveness to self-motion during vertebrate locomotion. Here, using semi-isolated in vitro preparations of larval Xenopus, we demonstrate that shared efferent neural pathways to hair cells of vestibular endorgans and lateral line neuromasts express cyclic impulse bursts during swimming that are directly driven by spinal locomotor circuitry. Despite common efferent innervation and discharge patterns, afferent signal encoding at the two mechanosensory peripheries is influenced differentially by efference copy signals, reflecting the different organization of body/water motion-detecting processes in the vestibular and lateral line systems. The resultant overall gain reduction in sensory signal encoding in both cases, which likely prevents overstimulation, constitutes an adjustment to increased stimulus magnitudes during locomotion.

  15. Biorobotics: using robots to emulate and investigate agile locomotion.

    Science.gov (United States)

    Ijspeert, Auke J

    2014-10-10

    The graceful and agile movements of animals are difficult to analyze and emulate because locomotion is the result of a complex interplay of many components: the central and peripheral nervous systems, the musculoskeletal system, and the environment. The goals of biorobotics are to take inspiration from biological principles to design robots that match the agility of animals, and to use robots as scientific tools to investigate animal adaptive behavior. Used as physical models, biorobots contribute to hypothesis testing in fields such as hydrodynamics, biomechanics, neuroscience, and prosthetics. Their use may contribute to the design of prosthetic devices that more closely take human locomotion principles into account. Copyright © 2014, American Association for the Advancement of Science.

  16. The coal-fired gas turbine locomotive - A new look

    Science.gov (United States)

    Liddle, S. G.; Bonzo, B. B.; Purohit, G. P.

    1983-01-01

    Advances in turbomachine technology and novel methods of coal combustion may have made possible the development of a competitive coal fired gas turbine locomotive engine. Of the combustor, thermodynamic cycle, and turbine combinations presently assessed, an external combustion closed cycle regenerative gas turbine with a fluidized bed coal combustor is judged to be the best suited for locomotive requirements. Some merit is also discerned in external combustion open cycle regenerative systems and internal combustion open cycle regenerative gas turbine systems employing a coal gasifier. The choice of an open or closed cycle depends on the selection of a working fluid and the relative advantages of loop pressurization, with air being the most attractive closed cycle working fluid on the basis of cost.

  17. The Perceived Naturalness of Virtual Walking Speeds during WIP Locomotion

    DEFF Research Database (Denmark)

    Nilsson, Niels Chr.; Serafin, Stefania; Nordahl, Rolf

    2016-01-01

    It is well established that individuals tend to underestimate visually presented walking speeds when relying on treadmills for virtual walking. However, prior to the present studies this perceptual distortion had not been observed in relation to Walking-in-Place (WIP) locomotion, and a number...... of the factors contributing to the perceptual distortion have yet to be identified. In this paper we present a summary of seven of our studies investigating what factors that influence self-motion perception during virtual walking and two meta-analyses of the findings of the seven studies. The studies relate...... to how gait cycle characteristics, visual display properties, and methodological differences affect speed underestimation during treadmill and WIP locomotion. The studies suggested the following: A significant main effect was found for step frequency; both display and geometric field of view were...

  18. Modern power electronics for locomotives; Moderne Leistungselektronik im Lokomotiveinsatz

    Energy Technology Data Exchange (ETDEWEB)

    Bakran, M.M.; Eckel, H.G.; Nagel, A. [Siemens AG, Nuernberg (Germany)

    2007-07-01

    Locomotives represent a challenging application for high-power electronics in terms of power, voltage-level and operating conditions. The driving forces are the development of semiconductor devices, the corresponding circuit topologies and the resulting drive properties. The transition from GTO to IGBT allowed building more compact converters with a more flexible power rating. This for example made the integration of the auxiliary converter an effective solution. The development of 6.5kV IGBTs made possible easier operation on the 3kV-dc line, however, still with optimized and different solutions for multisystem locomotives. The actual development of semiconductor technology still suggests a further increase in power density. (orig.)

  19. Full-scale locomotive dynamic crash testing and correlations : locomotive consist colliding with steel coil truck at grade crossing (test 3).

    Science.gov (United States)

    2011-09-01

    This report presents the test results and finite element correlations of a full-scale dynamic collision between a locomotive and a highway truck loaded with two heavy steel coils. The locomotive consist was moving at 58 miles per hour before it struc...

  20. Immediate effects of the trunk stabilizing exercise on static balance parameters in double-leg and one-leg stances

    OpenAIRE

    Kim, Jwa-jun; Park, Se-yeon

    2016-01-01

    [Purpose] The purpose of this study was to evaluate the immediate effect of stabilizing exercise using the PNF technique on standing balance in one-leg and double-leg stances. [Subjects and Methods] The present study recruited 34 healthy participants from a local university. The Participants performed four balance tests (double-leg stance with and without vision, one-leg stance with and without vision), before and after exercise. The exercise consisted of exercises performed using PNF techniq...

  1. Phalangeal joints kinematics in ostrich (Struthio camelus) locomotion on sand

    Science.gov (United States)

    Han, Dianlei; Wan, Haijin; Li, Xiujuan; Luo, Gang; Xue, Shuliang; Ma, Songsong; Yang, Mingming; Li, Jianqiao

    2018-01-01

    In ostriches, the toes are the only body parts that contact loose sand surfaces. Thus, toe interphalangeal joint motions may play vital biomechanical roles. However, there is little research on ostrich phalangeal joint movements while walking or running on sand. The results from the three-dimensional motion track analysis system Simi Motion show that gait pattern has no significant effect on the key indicators (angles at touch-down, mid-stance, lift-off and range of motion) of the toe joint angles. The motion of the toe phalanges when walking and running on sand is basically the same. The ground medium is the key factor that changes the toe postures adopted by ostriches during the stance phase in slow to fast locomotion. The 3rd toe and the 4th toe are connected by the interphalangeal ligament, and the motions of the MTP3 and MTP4 joints are highly synchronized on a loose sand substrate. The 3rd toe and 4th toe are coupled to maintain static balance in slow locomotion and dynamic balance in fast locomotion. In addition, the gait pattern has a marked effect on the range of forward displacement of the toenail (YTN). The ostrich toenail plays an important role in preventing slip and provides traction at push-off in a sandy environment. The metatarsophalangeal joint plays an important role in energy saving during fast locomotion on loose sand substrates. Simulation reveals that the particle velocity field, particle force field and sand particle disturbance in the running gait are denser than those in the walking gait. PMID:29489844

  2. Dynamic Locomotion and Whole-Body Control for Compliant Humanoids

    OpenAIRE

    Hopkins, Michael Anthony

    2015-01-01

    With the ability to navigate natural and man-made environments and utilize standard human tools, humanoid robots have the potential to transform emergency response and disaster relief applications by serving as first responders in hazardous scenarios. Such applications will require major advances in humanoid control, enabling robots to traverse difficult, cluttered terrain with both speed and stability. To advance the state of the art, this dissertation presents a complete dynamic locomotion ...

  3. Brief anesthesia, but not voluntary locomotion, significantly alters cortical temperature

    Science.gov (United States)

    Shirey, Michael J.; Kudlik, D'Anne E.; Huo, Bing-Xing; Greene, Stephanie E.; Drew, Patrick J.

    2015-01-01

    Changes in brain temperature can alter electrical properties of neurons and cause changes in behavior. However, it is not well understood how behaviors, like locomotion, or experimental manipulations, like anesthesia, alter brain temperature. We implanted thermocouples in sensorimotor cortex of mice to understand how cortical temperature was affected by locomotion, as well as by brief and prolonged anesthesia. Voluntary locomotion induced small (∼0.1°C) but reliable increases in cortical temperature that could be described using a linear convolution model. In contrast, brief (90-s) exposure to isoflurane anesthesia depressed cortical temperature by ∼2°C, which lasted for up to 30 min after the cessation of anesthesia. Cortical temperature decreases were not accompanied by a concomitant decrease in the γ-band local field potential power, multiunit firing rate, or locomotion behavior, which all returned to baseline within a few minutes after the cessation of anesthesia. In anesthetized animals where core body temperature was kept constant, cortical temperature was still >1°C lower than in the awake animal. Thermocouples implanted in the subcortex showed similar temperature changes under anesthesia, suggesting these responses occur throughout the brain. Two-photon microscopy of individual blood vessel dynamics following brief isoflurane exposure revealed a large increase in vessel diameter that ceased before the brain temperature significantly decreased, indicating cerebral heat loss was not due to increased cerebral blood vessel dilation. These data should be considered in experimental designs recording in anesthetized preparations, computational models relating temperature and neural activity, and awake-behaving methods that require brief anesthesia before experimental procedures. PMID:25972579

  4. The role of vortices in animal locomotion in fluids

    Directory of Open Access Journals (Sweden)

    Dvořák R.

    2014-12-01

    Full Text Available The aim of this paper is to show the significance of vortices in animal locomotion in fluids on two deliberately chosen examples. The first example concerns lift generation by bird and insect wings, the second example briefly mentiones swimming and walking on water. In all the examples, the vortices generated by the moving animal impart the necessary momentum to the surrounding fluid, the reaction to which is the force moving or lifting the animal.

  5. Performance analysis of jump-gliding locomotion for miniature robotics.

    Science.gov (United States)

    Vidyasagar, A; Zufferey, Jean-Christohphe; Floreano, Dario; Kovač, M

    2015-03-26

    Recent work suggests that jumping locomotion in combination with a gliding phase can be used as an effective mobility principle in robotics. Compared to pure jumping without a gliding phase, the potential benefits of hybrid jump-gliding locomotion includes the ability to extend the distance travelled and reduce the potentially damaging impact forces upon landing. This publication evaluates the performance of jump-gliding locomotion and provides models for the analysis of the relevant dynamics of flight. It also defines a jump-gliding envelope that encompasses the range that can be achieved with jump-gliding robots and that can be used to evaluate the performance and improvement potential of jump-gliding robots. We present first a planar dynamic model and then a simplified closed form model, which allow for quantification of the distance travelled and the impact energy on landing. In order to validate the prediction of these models, we validate the model with experiments using a novel jump-gliding robot, named the 'EPFL jump-glider'. It has a mass of 16.5 g and is able to perform jumps from elevated positions, perform steered gliding flight, land safely and traverse on the ground by repetitive jumping. The experiments indicate that the developed jump-gliding model fits very well with the measured flight data using the EPFL jump-glider, confirming the benefits of jump-gliding locomotion to mobile robotics. The jump-glide envelope considerations indicate that the EPFL jump-glider, when traversing from a 2 m height, reaches 74.3% of optimal jump-gliding distance compared to pure jumping without a gliding phase which only reaches 33.4% of the optimal jump-gliding distance. Methods of further improving flight performance based on the models and inspiration from biological systems are presented providing mechanical design pathways to future jump-gliding robot designs.

  6. Nigral Glutamatergic Neurons Control the Speed of Locomotion.

    Science.gov (United States)

    Ryczko, Dimitri; Grätsch, Swantje; Schläger, Laura; Keuyalian, Avo; Boukhatem, Zakaria; Garcia, Claudia; Auclair, François; Büschges, Ansgar; Dubuc, Réjean

    2017-10-04

    The mesencephalic locomotor region (MLR) plays a crucial role in locomotor control. In vertebrates, stimulation of the MLR at increasing intensities elicits locomotion of growing speed. This effect has been presumed to result from higher brain inputs activating the MLR like a dimmer switch. Here, we show in lampreys ( Petromyzon marinus ) of either sex that incremental stimulation of a region homologous to the mammalian substantia nigra pars compacta (SNc) evokes increasing activation of MLR cells with a graded increase in the frequency of locomotor movements. Neurons co-storing glutamate and dopamine were found to project from the primal SNc to the MLR. Blockade of glutamatergic transmission largely diminished MLR cell responses and locomotion. Local blockade of D 1 receptors in the MLR decreased locomotor frequency, but did not disrupt the SNc-evoked graded control of locomotion. Our findings revealed the presence of a glutamatergic input to the MLR originating from the primal SNc that evokes graded locomotor movements. SIGNIFICANCE STATEMENT The mesencephalic locomotor region (MLR) plays a crucial role in the control of locomotion. It projects downward to reticulospinal neurons that in turn activate the spinal locomotor networks. Increasing the intensity of MLR stimulation produces a growing activation of reticulospinal cells and a progressive increase in the speed of locomotor movements. Since the discovery of the MLR some 50 years ago, it has been presumed that higher brain regions activate the MLR in a graded fashion, but this has not been confirmed yet. Here, using a combination of techniques from cell to behavior, we provide evidence of a new glutamatergic pathway activating the MLR in a graded fashion, and consequently evoking a progressive increase in locomotor output. Copyright © 2017 the authors 0270-6474/17/379759-12$15.00/0.

  7. Enhanced Caenorhabditis elegans locomotion in a structured microfluidic environment.

    Directory of Open Access Journals (Sweden)

    Sungsu Park

    Full Text Available BACKGROUND: Behavioral studies of Caenorhabditis elegans traditionally are done on the smooth surface of agar plates, but the natural habitat of C. elegans and other nematodes is the soil, a complex and structured environment. In order to investigate how worms move in such environments, we have developed a technique to study C. elegans locomotion in microstructures fabricated from agar. METHODOLOGY/PRINCIPAL FINDINGS: When placed in open, liquid-filled, microfluidic chambers containing a square array of posts, we discovered that worms are capable of a novel mode of locomotion, which combines the fast gait of swimming with the more efficient movements of crawling. When the wavelength of the worms matched the periodicity of the post array, the microstructure directed the swimming and increased the speed of C. elegans ten-fold. We found that mutants defective in mechanosensation (mec-4, mec-10 or mutants with abnormal waveforms (unc-29 did not perform this enhanced locomotion and moved much more slowly than wild-type worms in the microstructure. CONCLUSION/SIGNIFICANCE: These results show that the microstructure can be used as a behavioral screen for mechanosensory and uncoordinated mutants. It is likely that worms use mechanosensation in the movement and navigation through heterogeneous environments.

  8. Chimpanzee ankle and foot joint kinematics: Arboreal versus terrestrial locomotion.

    Science.gov (United States)

    Holowka, Nicholas B; O'Neill, Matthew C; Thompson, Nathan E; Demes, Brigitte

    2017-09-01

    Many aspects of chimpanzee ankle and midfoot joint morphology are believed to reflect adaptations for arboreal locomotion. However, terrestrial travel also constitutes a significant component of chimpanzee locomotion, complicating functional interpretations of chimpanzee and fossil hominin foot morphology. Here we tested hypotheses of foot motion and, in keeping with general assumptions, we predicted that chimpanzees would use greater ankle and midfoot joint ranges of motion during travel on arboreal supports than on the ground. We used a high-speed motion capture system to measure three-dimensional kinematics of the ankle and midfoot joints in two male chimpanzees during three locomotor modes: terrestrial quadrupedalism on a flat runway, arboreal quadrupedalism on a horizontally oriented tree trunk, and climbing on a vertically oriented tree trunk. Chimpanzees used relatively high ankle joint dorsiflexion angles during all three locomotor modes, although dorsiflexion was greatest in arboreal modes. They used higher subtalar joint coronal plane ranges of motion during terrestrial and arboreal quadrupedalism than during climbing, due in part to their use of high eversion angles in the former. Finally, they used high midfoot inversion angles during arboreal locomotor modes, but used similar midfoot sagittal plane kinematics across all locomotor modes. The results indicate that chimpanzees use large ranges of motion at their various ankle and midfoot joints during both terrestrial and arboreal locomotion. Therefore, we argue that chimpanzee foot anatomy enables a versatile locomotor repertoire, and urge caution when using foot joint morphology to reconstruct arboreal behavior in fossil hominins. © 2017 Wiley Periodicals, Inc.

  9. Control method for biped locomotion robots based on ZMP information

    Energy Technology Data Exchange (ETDEWEB)

    Kume, Etsuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1994-01-01

    The Human Acts Simulation Program (HASP) started as a ten year program of Computing and Information Systems Center (CISC) at Japan Atomic Energy Research Institute (JAERI) in 1987. A mechanical design study of biped locomotion robots for patrol and inspection in nuclear facilities is being performed as an item of the research scope. One of the goals of our research is to design a biped locomotion robot for practical use in nuclear facilities. So far, we have been studying for several dynamic walking patterns. In conventional control methods for biped locomotion robots, the program control is used based on preset walking patterns, so it dose not have the robustness such as a dynamic change of walking pattern. Therefore, a real-time control method based on dynamic information of the robot states is necessary for the high performance of walking. In this study a new control method based on Zero Moment Point (ZMP) information is proposed as one of real-time control methods. The proposed method is discussed and validated based on the numerical simulation. (author).

  10. Clinical quality indicators of venous leg ulcers

    DEFF Research Database (Denmark)

    Kjaer, Monica L; Mainz, Jan; Soernsen, Lars T

    2005-01-01

    and reliable evidence-based quality indicators of venous leg ulcer care. A Scandinavian multidisciplinary, cross-sectional panel of wound healing experts developed clinical quality indicators on the basis of scientific evidence from the literature and subsequent group nominal consensus of the panel......; an independent medical doctor tested the feasibility and reliability of these clinical indicators, assessing the quality of medical technical care on 100 consecutive venous leg ulcer patients. Main outcome measures were healing, recurrence, pain, venous disease diagnosis, differential diagnosis and treatment......%) were assessed for venous surgery. Distal arterial pressure was measured following initial examination in 33 of the patients (34%). All patients (100%) were prescribed compression therapy. Of the 98 patients, 11 (11%) had ulcers recur in 3 months and 72 (73%) healed in 12 months, which is in line...

  11. Is preeclampsia associated with restless legs syndrome?

    OpenAIRE

    Ramirez, J O; Cabrera, S A S; Hidalgo, H; Cabrera, S G; Linnebank, M; Bassetti, C L; Kallweit, U

    2013-01-01

    OBJECTIVE: Restless legs syndrome (RLS) is a common neurologic disorder. Secondary RLS includes pregnancy and iron deficiency. Prevalence of RLS in pregnancy ranges from 11% to 27%. We aimed to assess the frequency and characteristics of RLS in pregnancy in a Peruvian population and to evaluate the possible pregnancy or delivery complications due to RLS. METHODS: We assessed 218 consecutive expectant mothers at the inpatient clinic of the Hospital San Bartolome in Lima, Peru. Assessment wa...

  12. Genetic aspects of restless legs syndrome

    OpenAIRE

    Dhawan, V; Ali, M; Chaudhuri, K R

    2006-01-01

    Restless legs syndrome (RLS), also known as Ekbom syndrome, is a common movement disorder with sensorimotor symptoms occurring during sleep and quiet wakefulness. The underlying cause for RLS is unknown but genetic influences play a strong part in the pathogenesis of RLS, particularly when the condition starts at a young age. This review explores the genetic basis of RLS and related phenotypic variations. Recently, three loci showing vulnerability to RLS have been described in French‐Canadian...

  13. Restless legs syndrome and pregnancy: A review

    OpenAIRE

    Srivanitchapoom, Prachaya; Pandey, Sanjay; Hallett, Mark

    2014-01-01

    Restless legs syndrome (RLS) is a common sensorimotor neurological disorder that is diagnosed according to the revised criteria of the International RLS Study Group (IRLSSG). The pathophysiology of RLS is still unknown and its prevalence is influenced by ethnicity, age, and gender. RLS is divided into two types by etiology: primary or idiopathic and secondary. Primary RLS is strongly influenced by a genetic component while secondary RLS is caused by other associated conditions such as end-sta...

  14. An Evidence-based Analysis of the Association between Periodic Leg Movements during Sleep and Arousals in Restless Legs Syndrome.

    Science.gov (United States)

    Ferri, Raffaele; Rundo, Francesco; Zucconi, Marco; Manconi, Mauro; Bruni, Oliviero; Ferini-Strambi, Luigi; Fulda, Stephany

    2015-06-01

    To analyze statistically the association between periodic leg movements during sleep (PLMS) and arousals, in order to eventually support or challenge the current scoring rules and to further understand their reciprocal influence. Sleep research center. Twenty untreated consecutive patients with restless legs syndrome (RLS) (13 women and 7 males, mean age 60.9 y). In each recording, we selected all PLMS/arousal pairs that met the following inclusion criteria: (a) PLMS events that were separated from another PLMS event (preceding or following) by at least 10 s of EMG inactivity; (b) arousal events separated from another arousal event (preceding or following) by at least 10 s of stable EEG baseline activity; (c) PLMS/arousal pairs were then selected among events identified according to the previous two criteria, when PLMS and arousals were separated (offset-to-onset) by no more than 10 s, regardless of which was first. We selected a mean of 46.1 (SD 25.55) PLMS/arousal pairs per subject; in these pairs, average PLMS duration was 3.2 s (0.65) and average arousal duration was 6.5 s (0.92). Within these event pairs, the great majority (on average 98.4%, SD 3.88) was separated by less than 0.5 s (i.e., between the end of one event and the onset of the other, regardless of which was first). Arousal onsets preceded PLMS onset in 41.2% of pairs, while the opposite was true for the remaining 58.8% of pairs. A significant correlation between PLMS duration and arousal duration was also found (r = 0.447, P definition of the association between periodic leg movements during sleep (PLMS) and arousals. The tight time relationship between PLMS and arousals and their correlated durations seem to indicate that both events might be regulated by a complex mechanism, rather than being connected by a simple reciprocal cause/effect relationship. © 2015 Associated Professional Sleep Societies, LLC.

  15. Sleep board review question: restless legs

    Directory of Open Access Journals (Sweden)

    Omobomi O

    2018-02-01

    Full Text Available No abstract available. Article truncated after 150 words. Ms. Jones (not her real name is a 63-year-old woman who states that she gets very fidgety when sitting in a theater, watching a movie or when flying long distances on a plane. She is unable to find words to describe the sensation but she states that moving her legs make them feel better. Lately, she has been getting this feeling almost every night. She reports no leg discomfort in the daytime. She denies muscle cramps her legs. She had some recent investigations done by her primary care physician because of complaints of fatigue. Which of the following will be helpful in the diagnosis and management in this patient? 1. An overnight polysomnogram showing apnea hypopnea index of 1.6 events per hour and no periodic limb movements (PLMs 2. Ferritin level of 18 ng/ml (normal range 20-200 ng/ml 3. Serum Bicarbonate of 29 mEq/L (normal range 23-29 mEq/L 4. Thyroid …

  16. Restless Legs Syndrome Among the Elderly

    Directory of Open Access Journals (Sweden)

    Pei-Hao Chen

    2009-12-01

    Full Text Available Restless legs syndrome is a sleep and movement disorder that affects 5–15% of the general population, with an increased prevalence among the elderly population. It not only affects quality of life but also increases risk of mortality among older adults. The diagnosis is based on clinical symptoms of the patient by four minimal essential criteria. Restless legs syndrome can be divided into primary or secondary causes. Examination should be performed to rule out potentially treatable illnesses, such as iron deficiency, renal failure or peripheral neuropathy, especially among elderly patients. The initial approach to restless legs syndrome should be nonpharmacologic management, such as good sleep hygiene, regular exercise, cognitive behavioral therapy and avoidance of certain aggravating drugs. An algorithm based on scientific evidence and expert opinion was developed for guidance of treatment. Combination or change of medication can be applied to resistant or difficult cases. Since elderly patients are prone to treatment-related side effects, the best strategy is to start medication cautiously and at the lowest recommended dosage.

  17. Pilot study on proximal femur strains during locomotion and fall-down scenario

    Energy Technology Data Exchange (ETDEWEB)

    Klodowski, Adam, E-mail: adam.klodowski@lut.fi; Valkeapaeae, Antti, E-mail: antti.valkeapaa@lut.fi; Mikkola, Aki, E-mail: aki.mikkola@lut.fi [Lappeenranta University of Technology (Finland)

    2012-09-15

    The most common and severe type of fracture among the elderly is known as a proximal femur fracture. Aging-related bone loss is one of the major contributing factors to increased likelihood of bone fracture. Specific exercises can be used to strain bones and increase bone strength to counter the effects of bone loss. The flexible multibody simulation approach can be used as a non-invasive method for estimating bone strains caused by physical activity. This method was recently used to analyze the strain of locomotion in regard to human femur and tibia leg bones. The current study focuses on strain analysis of the femoral neck. The research test person was a clinically healthy 65-year old Caucasian male. The computed tomography was used to build a geometrically accurate finite element model of the femur with inhomogeneous material properties derived from the voxel data. The anthropometric data was used to model the musculoskeletal system of the test person. The multibody skeletal model was utilized to estimate loading on the femoral neck during walking, which represents a routine daily activity. The flexible multibody simulation results were compared to strains that occurred during a simulated fall onto the greater trochanter of the femur. The fall simulation was made entirely using finite element software. Results from the finite element analysis were compared with the previous study showing that the test person does not belong to the high-risk hip fracture group. Finally, the estimated strains gathered from the walking simulation were compared to the strain values from the simulated fall-down scenario.

  18. Pectoral fin locomotion in batoid fishes: undulation versus oscillation.

    Science.gov (United States)

    Rosenberger, L J

    2001-01-01

    This study explores the dichotomy between undulatory (passing multiple waves down the fin or body) and oscillatory (flapping) locomotion by comparing the kinematics of pectoral fin locomotion in eight species of batoids (Dasyatis americana, D. sabina, D. say, D. violacea, Gymnura micrura, Raja eglanteria, Rhinobatos lentiginosus and Rhinoptera bonasus) that differ in their swimming behavior, phylogenetic position and lifestyle. The goals of this study are to describe and compare the pectoral fin locomotor behavior of the eight batoid species, to clarify how fin movements change with swimming speed for each species and to analyze critically the undulation/oscillation continuum proposed by Breder using batoids as an example. Kinematic data were recorded for each species over a range of swimming velocities (1-3 disc lengths s(-1)). The eight species in this study vary greatly in their swimming modes. Rhinobatos lentiginosus uses a combination of axial-based and pectoral-fin-based undulation to move forward through the water, with primary thrust generated by the tail. The pectoral fins are activated in short undulatory bursts for increasing swimming speed and for maneuvering. Raja eglanteria uses a combination of pectoral and pelvic locomotion, although only pectoral locomotion is analyzed here. The other six species use pectoral locomotion exclusively to propel themselves through the water. Dasyatis sabina and D. say have the most undulatory fins with an average of 1.3 waves per fin length, whereas Rhinoptera bonasus has the most oscillatory fin behavior with 0.4 waves per fin length. The remaining species range between these two extremes in the degree of undulation present on their fins. There is an apparent trade-off between fin-beat frequency and amplitude. Rhinoptera bonasus has the lowest frequency and the highest fin amplitude, whereas Rhinobatos lentiginosus has the highest frequency and the lowest amplitude among the eight species examined. The kinematic

  19. Stable isotopes labelled compounds

    International Nuclear Information System (INIS)

    1982-09-01

    The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

  20. Stable Boundary Layer Issues

    NARCIS (Netherlands)

    Steeneveld, G.J.

    2012-01-01

    Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The

  1. Evolutionary Stable Strategy

    Indian Academy of Sciences (India)

    IAS Admin

    After Maynard-Smith and Price [1] mathematically derived why a given behaviour or strategy was adopted by a certain proportion of the population at a given time, it was shown that a strategy which is currently stable in a population need not be stable in evolutionary time (across generations). Additionally it was sug-.

  2. In situ UV curable 3D printing of multi-material tri-legged soft bot with spider mimicked multi-step forward dynamic gait

    Science.gov (United States)

    Zeb Gul, Jahan; Yang, Bong-Su; Yang, Young Jin; Chang, Dong Eui; Choi, Kyung Hyun

    2016-11-01

    Soft bots have the expedient ability of adopting intricate postures and fitting in complex shapes compared to mechanical robots. This paper presents a unique in situ UV curing three-dimensional (3D) printed multi-material tri-legged soft bot with spider mimicked multi-step dynamic forward gait using commercial bio metal filament (BMF) as an actuator. The printed soft bot can produce controllable forward motion in response to external signals. The fundamental properties of BMF, including output force, contractions at different frequencies, initial loading rate, and displacement-rate are verified. The tri-pedal soft bot CAD model is designed inspired by spider’s legged structure and its locomotion is assessed by simulating strain and displacement using finite element analysis. A customized rotational multi-head 3D printing system assisted with multiple wavelength’s curing lasers is used for in situ fabrication of tri-pedal soft-bot using two flexible materials (epoxy and polyurethane) in three layered steps. The size of tri-pedal soft-bot is 80 mm in diameter and each pedal’s width and depth is 5 mm × 5 mm respectively. The maximum forward speed achieved is 2.7 mm s‑1 @ 5 Hz with input voltage of 3 V and 250 mA on a smooth surface. The fabricated tri-pedal soft bot proved its power efficiency and controllable locomotion at three input signal frequencies (1, 2, 5 Hz).

  3. Can't Curb the Urge to Move? Living with Restless Legs Syndrome

    Science.gov (United States)

    ... Sleep? Wise Choices Recognizing Restless Legs Restless legs syndrome brings all 4 of these characteristics: A strong urge to move your legs, often with unpleasant feelings like tingling, burning or throbbing in the legs. Symptoms that get better ... Legs Syndrome Fact Sheet What Is Restless Legs Syndrome? Brain ...

  4. Association of Mode of Locomotion and Independence in Locomotion With Long-Term Outcomes After Spinal Cord Injury

    Science.gov (United States)

    Krause, James; Carter, Rickey E; Brotherton, Sandra

    2009-01-01

    Background/Objective: To explore the association of mode of locomotion (ambulation vs wheelchair use) and independence in locomotion (independent vs require assistance) with health, participation, and subjective well-being (SWB) after spinal cord injury (SCI). Research Design: Secondary analysis was conducted on survey data collected from 2 rehabilitation hospitals in the Midwest and a specialty hospital in the southeastern United States. The 1,493 participants were a minimum of 18 years of age and had traumatic SCI of at least 1 year duration at enrollment. Main Outcome Measures: Three sets of outcome measures were used: SWB, participation, and health. SWB was measured by 8 scales and a measure of depressive symptoms, participation by 3 items, health by general health ratings, days in poor health, hospitalizations, and treatments. Results: Small but significant associations were observed between independence in locomotion and every outcome. Ambulation was associated with greater participation but a mixed pattern of favorable and unfavorable health and SWB outcomes. Supplemental analyses were conducted on those who ambulated but who were dependent on others to do so (n = 117), because this group reported poor outcomes in several areas. Individuals who were independent in wheelchair use reported substantially better outcomes than nonwheelchair users and those dependent on others in wheelchair use. Conclusions: Although ambulation is often a recovery goal, individuals with SCI who ambulate do not uniformly report better outcomes than wheelchair users, and those who depend on others for assistance with ambulation may experience a unique set of problems. PMID:19810625

  5. Restless Legs Syndrome and Leg Motor Restlessness in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Keisuke Suzuki

    2015-01-01

    Full Text Available Sleep disturbances are important nonmotor symptoms in Parkinson’s disease (PD that are associated with a negative impact on quality of life. Restless legs syndrome (RLS, which is characterized by an urge to move the legs accompanied by abnormal leg sensations, can coexist with PD, although the pathophysiology of these disorders appears to be different. RLS and PD both respond favorably to dopaminergic treatment, and several investigators have reported a significant relationship between RLS and PD. Sensory symptoms, pain, motor restlessness, akathisia, and the wearing-off phenomenon observed in PD should be differentiated from RLS. RLS in PD may be confounded by chronic dopaminergic treatment; thus, more studies are needed to investigate RLS in drug-naïve patients with PD. Recently, leg motor restlessness (LMR, which is characterized by an urge to move the legs that does not fulfill the diagnostic criteria for RLS, has been reported to be observed more frequently in de novo patients with PD than in age-matched healthy controls, suggesting that LMR may be a part of sensorimotor symptoms intrinsic to PD. In this paper, we provide an overview of RLS, LMR, and PD and of the relationships among these disorders.

  6. Differences in take-off leg kinetics between horizontal and vertical single-leg rebound jumps.

    Science.gov (United States)

    Kariyama, Yasushi; Hobara, Hiroaki; Zushi, Koji

    2017-06-01

    This study aimed to clarify the differences between the horizontal single-leg rebound jump (HJ) and vertical single-leg rebound jump (VJ) in terms of three-dimensional joint kinetics for the take-off leg, while focusing on frontal and transverse plane movements. Eleven male track and field athletes performed HJ and VJ. Kinematic and kinetic data were calculated using data recorded with a motion capture system and force platforms. The hip abduction torque, trunk lateral flexion torque (flexion for the swing-leg side), hip external and internal torque, trunk rotational torque, and the powers associated with these torques were larger when performing HJ because of resistance to the impact ground reaction force and because of pelvic and posture control. Pelvic rotation was noted in HJ, and this was controlled not only by the hip and trunk joint torque from the transverse plane but also by the hip abduction torque. Therefore, hip and trunk joint kinetics in the frontal and transverse plane play an important role in a single-leg jump, regardless of the jumping direction, and may also play a more important role in HJ than in VJ.

  7. Effect of Renal Transplantation in Restless Legs Syndrome.

    Science.gov (United States)

    Kahvecioglu, Serdar; Yildiz, Demet; Buyukkoyuncu, Nilufer; Celik, Huseyin; Tufan, Fatih; Kılıç, Ahmet Kasım; Gul, Bulent; Yildiz, Abdulmecid

    2016-02-01

    Restless legs syndrome is a disorder in which patients have irresistible urge to move legs during rest. Restless legs syndrome seems to be common in end-stage renal disease. After a successful renal transplant, symptoms ameliorate with renal function improvement and restless legs syndrome is seen less in this population. Here, we aimed to investigate restless legs syndrome frequency and associated factors in renal transplant patients. In a cross-sectional study with 193 patients (116 hemodialysis patients, 45 transplant patients, and 32 controls), the presence of restless legs syndrome was assessed using the Restless Legs Syndrome Questionnaire. Medical history, demographic, and laboratory data were collected from the patients' medical records. Patients were questioned about the presence of restless legs syndrome using the Restless Legs Syndrome Questionnaire. Patients were evaluated with Beck Depression Scale for depression and Pittsburgh tests for sleep disturbances. While the rate of restless legs syndrome was similar between transplants and controls, it was significantly greater in hemodialysis patients. Hemodialysis patients and controls had similar depression scores that were higher compared with transplant patients. Pittsburgh score was similar in transplant patients and controls and significantly increased in the hemodialysis patients. The rate of insomnia was significantly higher in the hemodialysis patients compared with the other 2 groups. Logistic regression analysis revealed independent correlates of restless legs syndrome as insomnia, Beck depression score, and being on hemodialysis. Linear regression analysis showed that independent correlates of higher Pittsburgh score were higher depression score, higher age, and presence of restless legs syndrome. The prevalence of restless legs syndrome is significantly lower in transplant patients than it is in patients on maintenance dialysis. In renal transplant patients, restless legs syndrome frequency was

  8. The Relationship between Locomotive Syndrome and Depression in Community-Dwelling Elderly People

    OpenAIRE

    Misa Nakamura; Hiroshi Hashizume; Sachiko Nomura; Ryohei Kono; Hirotoshi Utsunomiya

    2017-01-01

    Locomotive syndrome (LS) is a concept that refers to the condition of people requiring healthcare services because of problems associated with locomotion. Depression is a major psychiatric disease among the elderly, in addition to dementia. The purpose of this study was to determine the association between LS and depression. The study participants were 224 healthy elderly volunteers living in a rural area in Japan. LS was defined as scores ≥ 16 on the 25-question Geriatric Locomotive Function...

  9. Closing the Loop: Integrating Body, Muscle and Environment with Locomotion Central Pattern Generators

    Science.gov (United States)

    2013-06-30

    between the neural circuitry, body, and fluid environment for swimming locomotion , where the lamprey serves as a model system1,2,3,4,5,6,7,8. Our...REPORT Final Report: Closing the Loop: Integrating Body, Muscle and Environment with Locomotion Central Pattern Generators 14. ABSTRACT 16. SECURITY...CLASSIFICATION OF: The role of sensory feedback is a central question in understanding vertebrate locomotion . Sensory feedback related to movement of

  10. Leg movements during wakefulness in restless legs syndrome: time structure and relationships with periodic leg movements during sleep.

    Science.gov (United States)

    Ferri, Raffaele; Manconi, Mauro; Plazzi, Giuseppe; Bruni, Oliviero; Cosentino, Filomena I I; Ferini-Strambi, Luigi; Zucconi, Marco

    2012-05-01

    Approximately one third of patients with restless legs syndrome (RLS) also show periodic leg movements (PLM) during relaxed wake fulness (PLMW). In contrast with the large amount of data published on periodic leg movements during sleep (PLMS), PLMW have received less attention from the scientific community. The objective of this study was to evaluate the correlations/differences of time-structure and response to a dopamine-agonist between PLMW and PLMS in patients with RLS. Ninety idiopathic RLS patients and 28 controls were recruited. Subjects underwent clinical and neurophysiological evaluation, hematological screening, and one or two consecutive full-night polysomnographic studies. A subset of patients received 0.25mg of pramipexole or placebo before the second recording. Polysomnographic recordings were scored and LM activity was analyzed during sleep and during the epochs of wakefulness occurring during the first recording hour. RLS patients had higher LM activity during wakefulness than controls, but with a similar periodicity. Even if correlated, the ability of the PLMW index to predict the PLMS index decreased with increasing LM activity. Intermovement intervals during wakefulness showed one peak only at approximately 4s, gradually decreasing with increasing interval in both patients and controls. The effect of pramipexole was very limited and involved the small periodic portion of LM activity during wakefulness. PLMW index and PLMS index were correlated; however, the magnitude of this correlation was not sufficient to suggest that PLMW can be good predictors of PLMS. Short-interval LM activity during wakefulness and sleep might be linked to the severity of sleep disruption in RLS patients and the differences between their features obtained during wakefulness or sleep might be relevant for the diagnosis of sleep disturbances in RLS. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Restless legs syndrome and nocturnal leg cramps: a review and guide to diagnosis and treatment.

    Science.gov (United States)

    Tipton, Philip W; Wszołek, Zbigniew K

    2017-12-22

    Restless legs syndrome (RLS) and nocturnal leg cramps (NLCs) are common disorders affecting 7.0% and 24.1% of the population in some European countries, respectively. Patients suffering from RLS experience uncomfortable nocturnal sensations in the legs with the urge to move that dissipates while moving. NLC is characterized by abrupt muscle contraction, most often in the gastrocnemius or foot muscles, which occurs at night and may result in significant sleep disturbances. The diagnosis of these disorders has presented a challenge to health care providers because of symptom overlap with other sensory and motor disturbances with nocturnal predominance. Treatment options and approaches are lacking, partially because of our currently incomplete understanding of the pathophysiological mechanisms underlying these conditions. We reviewed the medical literature to provide a comprehensive assessment of RLS and NLC with a focus on improved diagnostic accuracy and treatment approaches.

  12. INFLUENCE OF ROLLING STOCK VIBROACOUSTICAL PARAMETERS ON THE CHOICE OF RATIONAL VALUES OF LOCOMOTIVE RUNNING GEAR

    Directory of Open Access Journals (Sweden)

    Yu. V. Zelenko

    2016-06-01

    Full Text Available Purpose.The success of the traffic on the railways of Ukraine depends on the number and the operational fleet of electric locomotives. Today, the locomotive depot exploit physically and morally outdated locomotives that have low reliability. Modernization of electric locomotives is not economically justified. The aim of this study is to improve the safety of the traction rolling stock by the frequency analysis of dynamical systems, which allows conducting the calculation of the natural (of resonant frequencies of the design and related forms of vibrations.Methodology.The study was conducted by methods of analytical mechanics and mathematical modeling of operating loads of freight locomotive when driving at different speeds on the straight and curved track sections. The theoretical value of the work is the technique of choice of constructive schemes and rational parameters of perspective electric locomotive taking into account the electric inertia ratios and stiffness coefficients of Lagrange second-order equations.Findings. The problems of theoretical research and the development of a mathematical model of the spatial electric vibrations are solved. The theoretical studies of the effect of inertia ratios and stiffness coefficients on the dynamic values and the parameter values of electric locomotive undercarriages are presented.Originality.The set of developed regulations and obtained results is a practical solution to selecting rational parameters of bogies of the freight mainline locomotive for railways of Ukraine. A concept of choice of constructive scheme and rational parameters of perspective locomotive is formulated. It is developed the method of calculation of spatial electric locomotive oscillations to determine its dynamic performance. The software complex for processing the data of experimental studies of dynamic parameters of electric locomotive and comparing the results of the theoretical calculations with the data of full

  13. On designing geometric motion planners to solve regulating and trajectory tracking problems for robotic locomotion systems

    Energy Technology Data Exchange (ETDEWEB)

    Asnafi, Alireza [Hydro-Aeronautical Research Center, Shiraz University, Shiraz, 71348-13668 (Iran, Islamic Republic of); Mahzoon, Mojtaba, E-mail: asnafi@shirazu.ac.ir, E-mail: arasnafi@yahoo.com, E-mail: mahzoon@shirazu.ac.ir [Department of Mechanical Engineering, School of Engineering, Shiraz University, Shiraz, 71348-13668 (Iran, Islamic Republic of)

    2011-09-15

    Based on a geometric fiber bundle structure, a generalized method to solve both regulation and trajectory tracking problems for locomotion systems is presented. The method is especially applied to two case studies of robotic locomotion systems; a three link articulated fish-like robot as a prototype of locomotion systems with symmetry, and the snakeboard as a prototype of mixed locomotion systems. Our results show that although these motion planners have an open loop structure, due to their generalities, they can steer case studies with negligible errors for almost any complicated path.

  14. Actigraphic assessment of periodic leg movements in patients with restless legs syndrome.

    Science.gov (United States)

    Cippà, Maria A T; Baumann, Christian R; Siccoli, Massimiliano M; Bassetti, Claudio L; Poryazova, Rositsa; Werth, Esther

    2013-10-01

    The diagnosis of restless legs syndrome (RLS) relies upon diagnostic criteria which are based on history only, and dopaminergic treatment is not normally the first choice of treatment for all patients. It would be worthwhile to identify patients non-responsive to dopaminergic treatment beforehand, because they may suffer from a restless legs-like syndrome and may require alternative treatment. We included retrospectively 24 adult patients fulfilling the four essential criteria for restless legs and 12 age-matched healthy controls. They were investigated by ambulatory actigraphy from both legs over three nights, and patients started treatment with dopamine agonists after this diagnostic work-up. We examined 12 responders to dopaminergic treatment and 12 non-responders and studied the association between response to dopaminergic treatment and the periodic limb movement index (PLMI) as assessed with actigraphy. Demographic characteristics, excessive daytime sleepiness and fatigue at baseline were similar in all three groups. Baseline RLS severity was similar between responders and non-responders [International Restless Legs Severity Scale (IRLS): 25 ± 9 and 24 ± 8]. Group comparisons of PLMI before treatment initiation showed significant differences between the three groups. Post-hoc pairwise comparisons revealed that healthy controls had significantly lower PLMI (4.9 ± 4.5) than responders (29.3 ± 22.7) and non-responders (13.3 ± 11.2). Similarly, the PLMI in responders was lower than in non-responders. PLMI day-to-day variability did not differ between responders and non-responders and there was no correlation between treatment effect, as assessed by the decrease of the IRLS and baseline PLMI. Our retrospective study indicates that actigraphy to assess periodic limb movements may contribute to a better diagnosis of dopamine-responsive restless legs syndrome. © 2013 European Sleep Research Society.

  15. Immobilization tests and periodic leg movements in sleep for the diagnosis of restless leg syndrome.

    Science.gov (United States)

    Montplaisir, J; Boucher, S; Nicolas, A; Lesperance, P; Gosselin, A; Rompré, P; Lavigne, G

    1998-03-01

    Patients with restless leg syndrome (RLS) complain of motor restlessness, usually occurring while they rest in the evening. Two immobilization tests have been described to assess leg restlessness in these patients. In the first test, the patient sits in bed with his or her legs outstretched while electromyograms are recorded from right and left anterior tibialis muscles for an hour (Suggested Immobilization Test [SIT]); in the second test, the legs are immobilized in a stretcher (Forced Immobilization Test [FIT]). In the current study, the SIT and the FIT were compared in patients with RLS and normal control subjects matched for age and sex. More leg movements were seen in patients than in controls during immobilization tests, especially the SIT. These movements were periodic, occurring at a frequency of approximately one every 12 seconds. The SIT (index > 40) was found to discriminate between RLS and control subjects better than the FIT (index > 25). Patients were also recorded during two consecutive nights to measure periodic leg movements in sleep (PLMS). A SIT index greater than 40 and a PLMS index greater than 11 (highest PLMS index of 2 consecutive nights) were found to discriminate patients with RLS from control subjects with similar power. With each of these two measures, the clinical diagnosis was correctly predicted in 81% of patients and 81% of the control subjects. The SIT has several advantages over the measure of the PLMS index; it does not require an all-night polygraphic recording and can be administered several times a day to measure circadian fluctuation of motor restlessness.

  16. Profile of altered brain iron acquisition in restless legs syndrome

    Science.gov (United States)

    Ponnuru, Padmavathi; Wang, Xin-Sheng; Patton, Stephanie M.; Allen, Richard P.; Earley, Christopher J.

    2011-01-01

    Restless legs syndrome is a neurological disorder characterized by an urgency to move the legs during periods of rest. Data from a variety of sources provide a compelling argument that the amount of iron in the brain is lower in individuals with restless legs syndrome compared with neurologically normal individuals. Moreover, a significant percentage of patients with restless legs syndrome are responsive to intravenous iron therapy. The mechanism underlying the decreased iron concentrations in restless legs syndrome brains is unknown. We hypothesize that the source of the brain iron deficit is at the blood–brain interface. Thus we analysed the expression of iron management proteins in the epithelial cells of the choroid plexus and the brain microvasculature in post-mortem tissues. The choroid plexus, obtained at autopsy, from 18 neurologically normal controls and 14 individuals who had primary restless legs syndrome was subjected to histochemical staining for iron and immunostaining for iron management proteins. Iron and heavy chain ferritin staining was reduced in the epithelial cells of choroid plexus in restless legs syndrome. Divalent metal transporter, ferroportin, transferrin and its receptor were upregulated in the choroid plexus in restless legs syndrome. Microvessels were isolated from the motor cortex of 11 restless legs syndrome and 14 control brains obtained at autopsy and quantitative immunoblot analyses was performed. Expression of heavy chain ferritin, transferrin and its receptor in the microvessels from restless legs syndrome was significantly decreased compared with the controls but divalent metal protein 1, ferroportin, prohepcidin, mitochondrial ferritin and light-chain ferritin remained unchanged. The presence of an iron regulatory protein was demonstrated in the brain microvasculature and the activity of this protein is decreased in restless legs syndrome; a finding similar to our earlier report in neuromelanin cells from the substantia

  17. Normal modified stable processes

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Shephard, N.

    2002-01-01

    This paper discusses two classes of distributions, and stochastic processes derived from them: modified stable (MS) laws and normal modified stable (NMS) laws. This extends corresponding results for the generalised inverse Gaussian (GIG) and generalised hyperbolic (GH) or normal generalised inverse...... Gaussian (NGIG) laws. The wider framework thus established provides, in particular, for added flexibility in the modelling of the dynamics of financial time series, of importance especially as regards OU based stochastic volatility models for equities. In the special case of the tempered stable OU process...

  18. Applications of stable isotopes

    International Nuclear Information System (INIS)

    Letolle, R.; Mariotti, A.; Bariac, T.

    1991-06-01

    This report reviews the historical background and the properties of stable isotopes, the methods used for their measurement (mass spectrometry and others), the present technics for isotope enrichment and separation, and at last the various present and foreseeable application (in nuclear energy, physical and chemical research, materials industry and research; tracing in industrial, medical and agronomical tests; the use of natural isotope variations for environmental studies, agronomy, natural resources appraising: water, minerals, energy). Some new possibilities in the use of stable isotope are offered. A last chapter gives the present state and forecast development of stable isotope uses in France and Europe

  19. Leg movement tracking in automatic video-based one-leg stance evaluation.

    Science.gov (United States)

    Kawa, Jacek; Stępień, Paula; Kapko, Wojciech; Niedziela, Aleksandra; Derejczyk, Jarosław

    2018-04-01

    Falls are a major risk in elder population. Early diagnosis is therefore an important step towards increasing the safety of elders. One of the common diagnostic tests is the Berg Balance Scale (BBS), consisting of 14 exercises arranged from the easiest (sitting-to-standing) to the most demanding (one-leg stance). In this study a novel approach to the automatic assessment of the time in which the patient can remain in the one-leg stance position without loosing balance is introduced. The data is collected using a regular video camera. No markers, special garments, or system calibration are required. Two groups are examined. The first group consists of 16 students: healthy, young adults (12 female, 4 male, avg. 20yrs±1). The second group consists of 50 elders (39 female, 11 male, avg. 78.8yrs±5.9). Data (short, one minute recordings) are collected in a controlled environment using a digital video recorder (50fps, 1920×1080) fixed to a tripod. Data are processed off-line. First, the region of interest is determined. Next, the Kanade-Lucas-Tomasi tracking is performed. Best tracks are selected based on the registered vertical movement and two tracks are obtained corresponding to the left and right leg movements. Tracks are later subjected to the sparse signal baseline estimation, denoising and thresholding to detect the raised leg. Results are compared frame-wise to the ground truth reference obtained in the manual processing procedure. Both legs are evaluated in the elder group (in all cases several attempts featuring both legs were registered), resulting in 89.18%±11.27% DICE, 93.07%±5.43% sensitivity and 96.94%±6.11% specificity values for both legs. The signal of a single leg is evaluated in the student group (in all cases only one attempt was needed to perform the full examination) resulting in 98.96%±1.2% DICE, 98.78%±1.65% sensitivity and 98.73%±2.69% specificity values. This is the first step towards a video-based system enabling the automatic

  20. Relationship between Leg Mass, Leg Composition and Foot Velocity on Kicking Accuracy in Australian Football.

    Science.gov (United States)

    Hart, Nicolas H; Nimphius, Sophia; Spiteri, Tania; Cochrane, Jodie L; Newton, Robert U

    2016-06-01

    Kicking a ball accurately over a desired distance to an intended target is arguably the most important skill to acquire in Australian Football. Therefore, understanding the potential mechanisms which underpin kicking accuracy is warranted. The aim of this study was to examine the relationship between leg mass, leg composition and foot velocity on kicking accuracy in Australian Football. Thirty-one Australian Footballers (n = 31; age: 22.1 ± 2.8 years; height: 1.81 ± 0.07 m; weight: 85.1 ± 13.0 kg; BMI: 25.9 ± 3.2) each performed ten drop punt kicks over twenty metres to a player target. Athletes were separated into accurate (n = 15) and inaccurate (n = 16) kicking groups. Leg mass characteristics were assessed using whole body DXA scans. Foot velocity was determined using a ten-camera optoelectronic, three-dimensional motion capture system. Interactions between leg mass and foot velocity evident within accurate kickers only (r = -0.670 to -0.701). Relative lean mass was positively correlated with kicking accuracy (r = 0.631), while no relationship between foot velocity and kicking accuracy was evident in isolation (r = -0.047 to -0.083). Given the evident importance of lean mass, and its interaction with foot velocity for accurate kickers; future research should explore speed-accuracy, impulse-variability, limb co-ordination and foot-ball interaction constructs in kicking using controlled with-in subject studies to examine the effects of resistance training and skill acquisition programs on the development of kicking accuracy. Key pointsAccurate kickers expressed a very strong inverse relationship between leg mass and foot velocity. Inaccurate kickers were unable to replicate this, with greater volatility in their performance, indicating an ability of accurate kickers to mediate foot velocity to compensate for leg mass in order to deliver the ball over the required distance.Accurate kickers exhibited larger quantities of relative lean mass and lower quantities

  1. Lumbar spondylosis, lumbar spinal stenosis, knee pain, back muscle strength are associated with the locomotive syndrome: Rural population study in Japan.

    Science.gov (United States)

    Chiba, Daisuke; Tsuda, Eiichi; Wada, Kanichiro; Kumagai, Gentaro; Sasaki, Eiji; Nawata, Atsushi; Nakagomi, Sho; Takahashi, Ippei; Nakaji, Shigeyuki; Ishibashi, Yasuyuki

    2016-05-01

    To comprehensively investigate the clinical and physical factors associating with locomotive syndrome (Loc-S); the locomotorium-disability for daily life. 647 volunteers participated (247 males, 400 females, Age: 58.4 ± 11.0, BMI: 22.5 ± 3.3). Three self-assessment questionnaires were administered: 1) "25-question Geriatric Locomotive Function Scale" (GFLS-25) for evaluating Loc-S (GLFS-25 ≥ 16 defined as Loc-S); 2) "diagnostic support tool for LSS" (LSS-DST) for evaluating the prevalence of lumbar spinal stenosis (LSS); 3) Knee injury and Osteoarthritis Outcome Score (KOOS). Plain radiographs of the bilateral knees and lumbar spine were evaluated, and the severity of lumbar spondylosis (LS) and knee osteoarthritis (KOA) defined by Kellgren-Lawrence grade. Bone status was evaluated by using the osteo-sono assessment index (OSI) at the calcaneus. Isometric muscle strength of trunk and leg (Nm/kg, both extension and flexion) were evaluated. Linear regression analysis was performed to elucidate the factors concerned with GFLS-25 including age, sex, and BMI. Thirty-nine subjects (6.0%, 13 males, 26 females) were defined as having Loc-S. Single regression model showed that age, height, BMI, skeletal muscle mass, OSI, LSS, KOOS, the severity of LS and KOA, and trunk- and leg-muscle strength were correlated with the degree of GLFS-25. Stepwise multiple regression model showed that sex, height, LSS, KOOS, the severity of LS, and back muscle strength were significantly correlated with that of GLFS-25. In this cross-sectional study, pain status associated with LSS and knee joint, structural severity for LS, and back muscle strength primarily affected the degree of GFLS-25. For managing Loc-S, we must pay more intensive attention to these factors. Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

  2. Robust and efficient walking with spring-like legs

    International Nuclear Information System (INIS)

    Rummel, J; Blum, Y; Seyfarth, A

    2010-01-01

    The development of bipedal walking robots is inspired by human walking. A way of implementing walking could be performed by mimicking human leg dynamics. A fundamental model, representing human leg dynamics during walking and running, is the bipedal spring-mass model which is the basis for this paper. The aim of this study is the identification of leg parameters leading to a compromise between robustness and energy efficiency in walking. It is found that, compared to asymmetric walking, symmetric walking with flatter angles of attack reveals such a compromise. With increasing leg stiffness, energy efficiency increases continuously. However, robustness is the maximum at moderate leg stiffness and decreases slightly with increasing stiffness. Hence, an adjustable leg compliance would be preferred, which is adaptable to the environment. If the ground is even, a high leg stiffness leads to energy efficient walking. However, if external perturbations are expected, e.g. when the robot walks on uneven terrain, the leg should be softer and the angle of attack flatter. In the case of underactuated robots with constant physical springs, the leg stiffness should be larger than k-tilde = 14 in order to use the most robust gait. Soft legs, however, lack in both robustness and efficiency.

  3. Loading and performance of the support leg in kicking.

    Science.gov (United States)

    Ball, Kevin

    2013-09-01

    The punt kick is important in many football codes and support leg kinematics and ground reaction forces have been implicated in injury and performance in kicking. To evaluate ground reaction forces and support leg kinematics in the punt kick. Cross sectional study. Seven elite Australian football players performed maximal kicks into a net using both the preferred and non-preferred legs. A force plate measured ground reaction forces and an optical motion capture system (200Hz) collected kinematic data during the stance phase of the kick. Preferred and non-preferred legs were compared and performance was evaluated by correlating parameters with foot speed at ball contact. Vertical forces were larger than running at a similar speed but did not reach levels that might be considered an injury risk. Braking forces were directed solely posteriorly, as for soccer kicks, but lateral force patterns varied with some players experiencing greater forces medially and others laterally. A more extended support leg, larger peak vertical and braking force during the stance phase and a shorter stance contact time was associated with larger kick leg foot speed at ball contact. No difference existed between the preferred and non-preferred legs for ground reaction forces or support leg mechanics. To punt kick longer, a straighter support leg, less time on the ground and stronger braking should be encouraged. Conditioning the support leg to provide stronger braking potential is recommended. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  4. Leg stiffness and sprint ability in amputee sprinters.

    Science.gov (United States)

    Hobara, Hiroaki; Tominaga, Shuichi; Umezawa, Shingo; Iwashita, Koudai; Okino, Atsuo; Saito, Taku; Usui, Fumio; Ogata, Toru

    2012-09-01

    Understanding leg stiffness (K (leg)) in amputee sprinters is important for the evaluation of their sprint ability and development of running-specific prostheses (RSP). To investigate K (leg) during hopping in amputee sprinters. Cross-sectional study. Seven transtibial (TT) and seven transfemoral (TF) amputee sprinters, as well as seven non-active able-bodied subjects, performed one-legged hopping matching metronome beats at 2.2 Hz. Amputees hopped on their sound limb whereas able-bodied (AB) subjects hopped on their dominant limb. Using a spring-mass model, K (leg) was calculated from the subjects' body mass, ground contact and flight times. Both TT and TF sprinters demonstrated significantly higher K (leg) than AB subjects. K (leg) during hopping on the sound leg significantly correlated with personal records attained in a 100-m sprint in both TT (r = -0.757) and TF sprinters (r = -0.855). The results of the present study suggest that amputee sprinters have a greater K (leg) during hopping than inactive non-amputees, and that their sprint ability can be predicted from the K (leg) during hopping at 2.2 Hz on the sound limb.

  5. Association between serum hepcidin level and restless legs syndrome.

    Science.gov (United States)

    Dauvilliers, Yves; Chenini, Sofiene; Vialaret, Jérôme; Delaby, Constance; Guiraud, Lily; Gabelle, Audrey; Lopez, Regis; Hirtz, Christophe; Jaussent, Isabelle; Lehmann, Sylvain

    2018-02-08

    To better understand the role of iron homeostasis dysregulation in restless legs syndrome, we compared serum hepcidin and ferritin levels in drug-free patients with primary restless legs syndrome and healthy controls and studied the relationship between hepcidin level and restless legs syndrome severity. One hundred and eight drug-free patients with primary restless legs syndrome (65 women; median age, 61.5 years) and 45 controls (28 women; median age, 53.9 years) were enrolled. Inclusion criteria were: normal ferritin level (>50 ng/mL) and absence of iron disorders, chronic renal or liver failure, and inflammatory or neurological diseases. Each subject underwent a thorough clinical examination and a polysomnography assessment. Serum hepcidin-25 was quantified using a validated mass spectrometry method. Restless legs syndrome severity was evaluated according to the International Restless Legs Syndrome Study Group. Despite no group difference between normal ferritin levels and demographic features, serum hepcidin level and hepcidin/ferritin ratio were higher in patients than in controls. Hepcidin level and hepcidin/ferritin ratio, but not ferritin level, were positively correlated with periodic leg movements during sleep and wakefulness in the whole sample. Hepcidin level seem to be associated with restless legs syndrome severity in a complex U-shaped relationship, without relationship with age at restless legs syndrome onset, positive family history, sleep and depressive symptoms, genetic background, and polysomnographic measurements. No relationship was found between ferritin level and restless legs syndrome severity. In drug-free patients with primary restless legs syndrome, hepcidin level is higher than in controls and may be associated with restless legs syndrome clinical severity. This result emphasizes the complex peripheral iron metabolism deregulation in restless legs syndrome, opening potential perspectives for a personalized approach with a hepcidin

  6. Analysing Stable Time Series

    National Research Council Canada - National Science Library

    Adler, Robert

    1997-01-01

    We describe how to take a stable, ARMA, time series through the various stages of model identification, parameter estimation, and diagnostic checking, and accompany the discussion with a goodly number...

  7. Sleep disturbances in restless legs syndrome

    Directory of Open Access Journals (Sweden)

    Jović Jasmina

    2018-01-01

    Full Text Available Background/Aim. Resteless legs syndrome (RLS is chronical neurological disorder characterized by urge to move legs that is usually accompanied by unpleasant sensations in the lower extremities. Sleep disturbance is one of the main accompanying symptoms of RLS which exists in approximatelly 90% of patients. Impairment of sleep is related to daily sleepiness, depressive and anxiety disorders. The aim of this study was to detect frequency and characterisitics of sleep-related symptoms in patients with RLS, and its impairrment to daily sleepiness, fatique, anxiety and depression. Methods. We have examinated 94 patients with RLS. The diagnose of RLS was based on questionnaire with 4 specific questions according to the International Restless Legs Syndrome Study Group (IRLSSG criteria updated in 2003. Severity of symptoms was astimated with IRLSSG Rating Scale, depression and anxiety with Hamilton Depression Rating Scale (HDRS and Hamilton Anxiety Rating Scale (HARS and sleepiness with Epworth Sleepiness scale (ESS. We astimated sleep characteristics and disturbances with specific questionnaire. Results. In our study 79.9% of patients had sleep-related symptoms. Average sleep duration was 6.50 ± 1.42 hours, with average frequency of awakening 2.34 ± 1.69 times per night. Average ESS score was 5.12 ± 4.08 (0–17. Patients with more severe symptoms had higher degree of sleepiness (p = 0.005. Patients with higher symptoms frequency, significantly more often had sleep disturbance (p = 0.016, tiredness and daily sleepiness (p = 0.001. Daily sleepiness (ESS also significantly correlates with depression (p < 0.05 and anxiety (p = 0.012. Conclusion. Our results confirm that sleep disturbances are one of the key accompanying symptoms of RLS which cause daily sleepiness, tiredness, depression and anxiety. Therefore, their early recognition and appropriate treatment must be a priority in RLS patients.

  8. [Bow legged adjectives in ancient literature].

    Science.gov (United States)

    Simon, Frantisek; Steger, Florian

    2011-01-01

    This article addresses the issue of capturing the medical entity called 'curved legs' in a terminologically exact way. In so doing, it refers to the long-lasting process of differentiation of exact nuances of meaning in Ancient Greek and Latin. In the chronological perusal of ancient Greek literature, it becomes evident that the various adjectives employed are often vague when looking at non-medical literature. By contrast, in the Hippocratic corpus these terms are for the first time annotated with explanations intended to lead to a more precise understanding of the described deformity. Further attempts of differentiation can be found in the writings of Galen, who not only distinguishes between outward and inward curvatures, but also between deformities of the thigh and lower leg as well as between pathological and natural curvatures. Latin literature also provides a series of adjectives that were initially often used in the meaning of 'curved' but it was not until Celsus that these were differentiated with respect to the type and direction of the curvature. When comparing Greek and Latin adjectives, it turns out that though the Latin term blaesus can be traced back etymologically to the Greek word beta lambda alpha iota sigma ó zeta, the meaning of beta lambda alpha iota sigma ó zeta does not fully correspond to that of the Latin word. It is not before the later common transliteration of Greek words that this adjective took on the meaning of beta lambda alpha iota sigma ó zeta; however, this was finally lost again. In summary, the article concludes that exact word meanings in ancient literature are often unclear and precise ascriptions of meanings are inconsistent. In the case of "curved legs," this has led to misunderstandings regarding the respective types and directions of the curvature.

  9. Nice snake, shame about the legs.

    Science.gov (United States)

    Coates; Ruta

    2000-12-01

    Snakes are one of the most extraordinary groups of terrestrial vertebrates, with numerous specializations distinguishing them from other squamates (lizards and their allies). Their musculoskeletal system allows creeping, burrowing, swimming and even gliding, and their predatory habits are aided by chemo- and thermoreceptors, an extraordinary degree of cranial kinesis and, sometimes, powerful venoms. Recent discoveries of indisputable early fossil snakes with posterior legs are generating intense debate about the evolutionary origin of these reptiles. New cladistic analyses dispute the precise significance and phylogenetic placement of these fossils. These conflicting hypotheses imply radically different scenarios of snake origins and relationships with wide biological implications.

  10. Leg ulcer in lepromatous leprosy - Case report*

    Science.gov (United States)

    Fernandes, Tania Rita Moreno de Oliveira; dos Santos, Talita Suzany Siqueira; Lopes, Ramon Rodrigues de Macedo

    2016-01-01

    In Brazil, leprosy is a widespread infectious and contagious disease. Clinicians and specialists view leprosy broadly as a systemic infection, since, in its manifestations, it mimics many conditions, such as rheumatic, vascular, ENT, neurological and dermatological diseases. There are few studies that characterize the factors associated with ulcers in leprosy. These injuries should be prevented and treated promptly to avoid serious problems like secondary infections, sepsis, carcinomatous degeneration and amputations. We describe a patient with ulcers on his legs, involving late diagnosis of lepromatous leprosy. PMID:27828650

  11. Painful legs and moving toes syndrome

    Directory of Open Access Journals (Sweden)

    Qiu-ying Ma

    2015-10-01

    Full Text Available Painful legs and moving toes syndrome (PLMT is a rare movement disorder with low diagnostic rate, which is characterized by lower limb pain with involuntary movements of feet or toes. Etiology and pathogenesis of this disease is still unclear. Patients have different clinical manifestations, so the diagnosis is difficult. Treatment methods for PLMT are numerous, but so far the treatment of this disease is still a major challenge for clinicians. Further research is still needed to guide clinical work. DOI: 10.3969/j.issn.1672-6731.2015.10.013

  12. Sexuality of Disabled Athletes Depending on the Form of Locomotion

    Directory of Open Access Journals (Sweden)

    Plinta Ryszard

    2015-12-01

    Full Text Available The main purpose of this study was to determine sexuality of disabled athletes depending on the form of locomotion. The study included 170 disabled athletes, aged between 18 and 45. The entire population was divided into 3 research groups depending on the form of locomotion: moving on wheelchairs (n=52, on crutches (n=29 and unaided (n=89. The research tool was a questionnaire voluntarily and anonymously completed by the respondents of the research groups. The questionnaire was composed of a general part concerning the socio-demographic conditions, medical history, health problems, a part dedicated to physical disability as well as the Polish version of the International Index of Erectile Function (IIEF and the Female Sexual Function Index (FSFI evaluating sexual life. STATISTICA 10.0 for Windows was used in the statistical analysis. Subjects moving on crutches were significantly older than ones moving on wheelchairs and unaided (34.41 ±11.00 vs. 30.49 ±10.44 and 27.99 ±10.51 years, respectively (p=0.018. Clinically significant erectile dysfunctions were most often diagnosed in athletes moving on wheelchairs (70.27%, followed by athletes moving on crutches and moving unaided (60% and 35.42%, respectively; p=0.048. Clinical sexual dysfunctions were diagnosed on a similar level among all female athletes. It was concluded that the form of locomotion may determine sexuality of disabled men. Males on wheelchair revealed the worst sexual functioning. Female athletes moving on wheelchairs, on crutches and moving unaided were comparable in the aspect of their sexual life.

  13. Benefit of "Push-pull" Locomotion for Planetary Rover Mobility

    Science.gov (United States)

    Creager, Colin M.; Moreland, Scott Jared; Skonieczny, K.; Johnson, K.; Asnani, V.; Gilligan, R.

    2011-01-01

    As NASAs exploration missions on planetary terrains become more aggressive, a focus on alternative modes of locomotion for rovers is necessary. In addition to climbing steep slopes, the terrain in these extreme environments is often unknown and can be extremely hard to traverse, increasing the likelihood of a vehicle or robot becoming damaged or immobilized. The conventional driving mode in which all wheels are either driven or free-rolling is very efficient on flat hard ground, but does not always provide enough traction to propel the vehicle through soft or steep terrain. This paper presents an alternative mode of travel and investigates the fundamental differences between these locomotion modes. The methods of push-pull locomotion discussed can be used with articulated wheeled vehicles and are identified as walking or inchinginch-worming. In both cases, the braked non-rolling wheels provide increased thrust. An in-depth study of how soil reacts under a rolling wheel vs. a braked wheel was performed by visually observing the motion of particles beneath the surface. This novel technique consists of driving or dragging a wheel in a soil bin against a transparent wall while high resolution, high-rate photographs are taken. Optical flow software was then used to determine shearing patterns in the soil. Different failure modes were observed for the rolling and braked wheel cases. A quantitative comparison of inching vs. conventional driving was also performed on a full-scale vehicle through a series of drawbar pull tests in the Lunar terrain strength simulant, GRC-1. The effect of tire stiffness was also compared; typically compliant tires provide better traction when driving in soft soil, however its been observed that rigid wheels may provide better thrust when non-rolling. Initial tests indicate up to a possible 40 increase in pull force capability at high slip when inching vs. rolling.

  14. Lightweight Multifunctional Planetary Probe for Extreme Environment Exploration and Locomotion

    Science.gov (United States)

    Bayandor, Javid (Principal Investigator); Schroeder, Kevin; Samareh, Jamshid

    2017-01-01

    The demand to explore new worlds requires the development of advanced technologies that enable landed science on uncertain terrains or in hard to reach locations. As a result, contemporary Entry, Descent, Landing, (EDL) and additional locomotion (EDLL) profiles are becoming increasingly more complex, with the introduction of lifting/guided entries, hazard avoidance on descent, and a plethora of landing techniques including airbags and the skycrane maneuver. The inclusion of each of these subsystems into a mission profile is associated with a substantial mass penalty. This report explores the new all-in-one entry vehicle concept, TANDEM, a new combined EDLL concept, and compares it to the current state of the art EDL systems. The explored system is lightweight and collapsible and provides the capacity for lifting/guided entry, guided descent, hazard avoidance, omnidirectional impact protection and surface locomotion without the aid of any additional subsystems. This Phase I study explored: 1. The capabilities and feasibility of the TANDEM concept as an EDLL vehicle. 2. Extensive impact analysis to ensure mission success in unfavorable landing conditions, and safe landing in Tessera regions. 3. Development of a detailed design for a conceptual mission to Venus. As a result of our work it was shown that: 1. TANDEM provides additional benefits over the Adaptive, Deployable Entry Placement Technology (ADEPT) including guided descent and surface locomotion, while reducing the mass by 38% compared to the ADEPT-VITaL mission. 2. Demonstrated that the design of tensegrity structures, and TANDEM specifically, grows linearly with an increase in velocity, which was previously unknown. 3. Investigation of surface impact revealed a promising results that suggest a properly configured TANDEM vehicle can safely land and preform science in the Tessera regions, which was previously labeled by the Decadal Survey as, largely inaccessible despite its high scientific interest. This work

  15. Partly shared spinal cord networks for locomotion and scratching.

    Science.gov (United States)

    Berkowitz, Ari; Hao, Zhao-Zhe

    2011-12-01

    Animals produce a variety of behaviors using a limited number of muscles and motor neurons. Rhythmic behaviors are often generated in basic form by networks of neurons within the central nervous system, or central pattern generators (CPGs). It is known from several invertebrates that different rhythmic behaviors involving the same muscles and motor neurons can be generated by a single CPG, multiple separate CPGs, or partly overlapping CPGs. Much less is known about how vertebrates generate multiple, rhythmic behaviors involving the same muscles. The spinal cord of limbed vertebrates contains CPGs for locomotion and multiple forms of scratching. We investigated the extent of sharing of CPGs for hind limb locomotion and for scratching. We used the spinal cord of adult red-eared turtles. Animals were immobilized to remove movement-related sensory feedback and were spinally transected to remove input from the brain. We took two approaches. First, we monitored individual spinal cord interneurons (i.e., neurons that are in between sensory neurons and motor neurons) during generation of each kind of rhythmic output of motor neurons (i.e., each motor pattern). Many spinal cord interneurons were rhythmically activated during the motor patterns for forward swimming and all three forms of scratching. Some of these scratch/swim interneurons had physiological and morphological properties consistent with their playing a role in the generation of motor patterns for all of these rhythmic behaviors. Other spinal cord interneurons, however, were rhythmically activated during scratching motor patterns but inhibited during swimming motor patterns. Thus, locomotion and scratching may be generated by partly shared spinal cord CPGs. Second, we delivered swim-evoking and scratch-evoking stimuli simultaneously and monitored the resulting motor patterns. Simultaneous stimulation could cause interactions of scratch inputs with subthreshold swim inputs to produce normal swimming, acceleration

  16. Biodiesel fuel costs and environmental issues when powering railway locomotives

    Energy Technology Data Exchange (ETDEWEB)

    Mirza, Abdul; Ziemer, Norbert; Tatara, Robert; Moraga, Reinaldo; Mirman, Clifford; Vohra, Promod

    2010-09-15

    Issues for adopting biodiesel fuel, instead of petrodiesel, to power railroad locomotives are engine performance and emissions, fuel infrastructure, and fuel cost. These are evaluated for B2 through B100 blends. Biodiesel's solvent action on fuel systems is addressed. With biodiesel, hydrocarbon, carbon monoxide, and particulate emissions are unchanged or reduced. Nitrogen oxides are elevated but it is believed that engine alterations can minimize these emissions. A Transportation Model, using data from a major railway, has demonstrated that refueling depots can be fully supplied with biodiesel at a pricing premium of 1% to 26%, depending on blend and geographical location.

  17. Human-robot interaction strategies for walker-assisted locomotion

    CERN Document Server

    Cifuentes, Carlos A

    2016-01-01

    This book presents the development of a new multimodal human-robot interface for testing and validating control strategies applied to robotic walkers for assisting human mobility and gait rehabilitation. The aim is to achieve a closer interaction between the robotic device and the individual, empowering the rehabilitation potential of such devices in clinical applications. A new multimodal human-robot interface for testing and validating control strategies applied to robotic walkers for assisting human mobility and gait rehabilitation is presented. Trends and opportunities for future advances in the field of assistive locomotion via the development of hybrid solutions based on the combination of smart walkers and biomechatronic exoskeletons are also discussed. .

  18. Designing presence for real locomotion in immersive virtual environments

    DEFF Research Database (Denmark)

    Turchet, Luca

    2015-01-01

    This paper describes a framework for designing systems for real locomotion in virtual environments (VEs) in order to achieve an intense sense of presence. The main outcome of the present research is a list of design features that the virtual reality technology should have in order to achieve...... that allows VE designers to evaluate the maturity of their systems and to pinpoint directions for future developments. A survey analysis was performed using the proposed framework, which involved three case studies to determine how many features of the proposed framework were present and their status...

  19. Improvement of fuel injection system of locomotive diesel engine.

    Science.gov (United States)

    Li, Minghai; Cui, Hongjiang; Wang, Juan; Guan, Ying

    2009-01-01

    The traditional locomotive diesels are usually designed for the performance of rated condition and much fuel will be consumed. A new plunger piston matching parts of fuel injection pump and injector nozzle matching parts were designed. The experimental results of fuel injection pump test and diesel engine show that the fuel consumption rate can be decreased a lot in the most of the working conditions. The forced lubrication is adopted for the new injector nozzle matching parts, which can reduce failure rate and increase service life. The design has been patented by Chinese State Patent Office.

  20. Biomechanical Analysis of Treadmill Locomotion on the International Space Station

    Science.gov (United States)

    De Witt, J. K.; Fincke, R. S.; Guilliams, M. E.; Ploutz-Snyder, L. L.

    2011-01-01

    Treadmill locomotion exercise is an important aspect of ISS exercise countermeasures. It is widely believed that an optimized treadmill exercise protocol could offer benefits to cardiovascular and bone health. If training heart rate is high enough, treadmill exercise is expected to lead to improvements in aerobic fitness. If impact or bone loading forces are high enough, treadmill exercise may be expected to contribute to improved bone outcomes. Ground-based research suggests that joint loads increase with increased running speed. However, it is unknown if increases in locomotion speed results in similar increases in joint loads in microgravity. Although data exist regarding the biomechanics of running and walking in microgravity, a majority were collected during parabolic flight or during investigations utilizing a microgravity analog. The Second Generation Treadmill (T2) has been in use on the International Space Station (ISS) and records the ground reaction forces (GRF) produced by crewmembers during exercise. Biomechanical analyses will aid in understanding potential differences in typical gait motion and allow for modeling of the human body to determine joint and muscle forces during exercise. By understanding these mechanisms, more appropriate exercise prescriptions can be developed that address deficiencies. The objective of this evaluation is to collect biomechanical data from crewmembers during treadmill exercise prior to and during flight. The goal is to determine if locomotive biomechanics differ between normal and microgravity environments and to determine how combinations of subject load and speed influence joint loading during in-flight treadmill exercise. Further, the data will be used to characterize any differences in specific bone and muscle loading during locomotion in these two gravitational conditions. This project maps to the HRP Integrated Research Plan risks including Risk of Bone Fracture (Gap B15), Risk of Early Onset Osteoporosis Due to