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Sample records for ankle torque steadiness

  1. Ankle torque steadiness is related to muscle activation variability and coactivation in children with cerebral palsy

    DEFF Research Database (Denmark)

    Bandholm, Thomas; Rose, Martin Høyer; Sløk, Rikke;

    2009-01-01

    The aims of this study were to: (1) investigate the significance of muscle activation variability and coactivation for the ability to perform steady submaximal ankle torque (torque steadiness) in healthy children and those with cerebral palsy (CP), and (2) assess ankle function during isometric...

  2. Ankle torque steadiness is related to muscle activation variability and co-activation in children with cerebral palsy

    DEFF Research Database (Denmark)

    Bandholm, Thomas; Rose, Martin; Sløk, Rikke;

    2009-01-01

    The aims of this study were to: (1) investigate the significance of muscle activation variability and coactivation for the ability to perform steady submaximal ankle torque (torque steadiness) in healthy children and those with cerebral palsy (CP), and (2) assess ankle function during isometric...

  3. Assessment of torque-steadiness reliability at the ankle level in healthy young subjects: implications for cerebral palsy

    DEFF Research Database (Denmark)

    Bandholm, Thomas; Rose, Martin Høyer; Sonne-Holm, Stig;

    2008-01-01

    It was the primary objective of this study to investigate whether quantifying fluctuations in dorsi and plantarflexor torque during submaximal isometric contractions is a reliable measurement in young healthy subjects. A secondary objective was to investigate the reliability of the associated mus...

  4. Neural-mechanical feedback control scheme generates physiological ankle torque fluctuation during quiet stance.

    Science.gov (United States)

    Vette, Albert H; Masani, Kei; Nakazawa, Kimitaka; Popovic, Milos R

    2010-02-01

    We have recently demonstrated in simulations and experiments that a proportional and derivative (PD) feedback controller can regulate the active ankle torque during quiet stance and stabilize the body despite a long sensory-motor time delay. The purpose of the present study was to: 1) model the active and passive ankle torque mechanisms and identify their contributions to the total ankle torque during standing and 2) investigate whether a neural-mechanical control scheme that implements the PD controller as the neural controller can successfully generate the total ankle torque as observed in healthy individuals during quiet stance. Fourteen young subjects were asked to stand still on a force platform to acquire data for model optimization and validation. During two trials of 30 s each, the fluctuation of the body angle, the electromyogram of the right soleus muscle, and the ankle torque were recorded. Using these data, the parameters of: 1) the active and passive torque mechanisms (Model I) and 2) the PD controller within the neural-mechanical control scheme (Model II) were optimized to achieve potential matching between the measured and predicted ankle torque. The performance of the two models was finally validated with a new set of data. Our results indicate that not only the passive, but also the active ankle torque mechanism contributes significantly to the total ankle torque and, hence, to body stabilization during quiet stance. In addition, we conclude that the proposed neural-mechanical control scheme successfully mimics the physiological control strategy during quiet stance and that a PD controller is a legitimate model for the strategy that the central nervous system applies to regulate the active ankle torque in spite of a long sensory-motor time delay. PMID:20071280

  5. Effects of imagery motor training on torque production of ankle plantar flexor muscles

    NARCIS (Netherlands)

    Zijdewind, Inge; Toering, ST; Bessem, B; van der Laan, O; Diercks, RL

    2003-01-01

    The aim of this study was to investigate in control subjects the effect of imagery training on the torque of plantar-flexor muscles of the ankle. Twenty-nine subjects were allocated to one of three groups that performed either imagery training, low-intensity strength training, or no training (only m

  6. Control of torque direction by spinal pathways at the cat ankle joint.

    Science.gov (United States)

    Nichols, T R; Lawrence, J H; Bonasera, S J

    1993-01-01

    To study the biomechanics of the calcaneal tendon's complex insertion onto the calcaneus, we measured torque-time trajectories exerted by the triceps surae and tibialis anterior muscles in eight unanesthetized decerebrate cats using a multi-axis force-moment sensor placed at the ankle joint. The ankle was constrained to an angle of 110 degrees plantarflexion. Muscles were activated using crossed-extension (XER), flexion (FWR), and caudal cutaneous sural nerve (SNR) reflexes. Torque contributions of other muscles activated by these reflexes were eliminated by denervation or tenotomy. In two animals, miniature pressure transducers were implanted among tendon fibers from the lateral gastrocnemius (LG) muscle that insert straight into the calcaneus or among tendon fibers from the medial gastrocnemius (MG) that cross over and insert on the lateral aspect of calcaneus. Reflexively evoked torques had the following directions: FWR, dorsiflexion and adduction; SNR, plantarflexion and abduction; and XER, plantarflexion and modest abduction or adduction. The proportion of abduction torque to plantarflexion torque was always greater for SNR than XER; this difference was about 50% of the magnitude of abduction torque generated by tetanic stimulation of the peronei. During SNR, pressures were higher in regions of the calcaneal tendon originating from MG than regions originating from LG. Similarly, pressures within the MG portion of the calcaneal tendon were higher during SNR than during XER, although these two reflexes produced matched ankle plantarflexion forces. Selective tenotomies and electromyographic recordings further demonstrated that MG generated most of the torque in response to SNR, while soleus, LG, and MG all generated torques in response to XER.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8150057

  7. Tremor irregularity, torque steadiness and rate of force development in Parkinson's disease

    DEFF Research Database (Denmark)

    Rose, Martin Høyer; Løkkegaard, Annemette; Sonne-Holm, Stig;

    2013-01-01

    idiopathic PD and 15 neurologically healthy matched controls performed isometric maximal contractions (extension/flexion) as well as steady submaximal and powerful isometric knee extensions. The patients with PD showed decreased isometric tremor irregularity. Torque steadiness was reduced in PD and the...... patients had increased muscle co-activation. A markedly lower RFD was found in PD and the decreased RFD correlated with reduced agonist muscle activation. Furthermore, patient RFD correlated with the Movement-Disorder-Society-Unified-Parkinson's-Disease-Rating-Scale 3 (motor part) scores. We concluded that...

  8. Enhancement in Steady State and Dynamic Performance of Direct Torque Control Induction Motor Drive

    Science.gov (United States)

    Singh, Bhoopendra; Jain, Shailendra; Dwivedi, Sanjeet

    2013-09-01

    An enhancement in dynamic performance of a traditional DTC drive can be achieved by a robust speed control algorithm while the steady state performance depends upon the switching strategy selected for minimization of torque ripples and an efficient flux control loop. In this paper a new torque ripple reduction technique with a modified look up table incorporating a larger number of synthesized non zero active voltage vectors is utilized to overcome the limitations of the conventionally controlled DTC drive. A fuzzy logic based speed controller and a low pass filter with tunable cutoff frequency for flux estimation is proposed in this paper. The proposed study is investigated through simulation and experimentally validated on a test drive.

  9. The stability of steady motion of magnetic domain wall: Role of higher-order spin-orbit torques

    Energy Technology Data Exchange (ETDEWEB)

    He, Peng-Bin, E-mail: hepengbin@hnu.edu.cn; Yan, Han; Cai, Meng-Qiu [School of Physics and Electronics, Hunan University, Changsha 410082 (China); Li, Zai-Dong [Department of Applied Physics, Hebei University of Technology, Tianjin 300401 (China)

    2015-12-14

    The steady motion of magnetic domain wall driven by spin-orbit torques is investigated analytically in the heavy/ferromagnetic metal nanowires for three cases with a current transverse to the in-plane and perpendicular easy axis, and along the in-plane easy axis. By the stability analysis of Walker wall profile, we find that if including the higher-order spin-orbit torques, the Walker breakdown can be avoided in some parameter regions of spin-orbit torques with a current transverse to or along the in-plane easy axis. However, in the case of perpendicular anisotropy, even considering the higher-order spin-orbit torques, the velocity of domain wall cannot be efficiently enhanced by the current. Furthermore, the direction of wall motion is dependent on the configuration and chirality of domain wall with a current along the in-plane easy axis or transverse to the perpendicular one. Especially, the direction of motion can be controlled by the initial chirality of domain wall. So, if only involving the spin-orbit mechanism, it is preferable to adopt the scheme of a current along the in-plane easy axis for enhancing the velocity and controlling the direction of domain wall.

  10. Joint kinetic response during unexpectedly reduced plantar flexor torque provided by a robotic ankle exoskeleton during walking

    OpenAIRE

    Kao, Pei-Chun; Lewis, Cara L.; Ferris, Daniel P

    2010-01-01

    During human walking, plantar flexor activation in late stance helps to generate a stable and economical gait pattern. Because plantar flexor activation is highly mediated by proprioceptive feedback, the nervous system must modulate reflex pathways to meet the mechanical requirements of gait. The purpose of this study was to quantify ankle joint mechanical output of the plantar flexor stretch reflex response during a novel unexpected gait perturbation. We used a robotic ankle exoskeleton to m...

  11. Steady-state domain wall motion driven by adiabatic spin-transfer torque with assistance of microwave field

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xi-guang; Guo, Guang-hua, E-mail: guogh@mail.csu.edu.cn; Nie, Yao-zhuang; Xia, Qing-lin; Tang, Wei [School of Physics and Electronics, Central South University, Changsha 410083 (China); Wang, D. [Department of Physics, National University of Defense Technology, Changsha 410073 (China); Zeng, Zhong-ming [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China)

    2013-12-23

    We have studied the current-induced displacement of a 180° Bloch wall by means of micromagnetic simulation and analytical approach. It is found that the adiabatic spin-transfer torque can sustain a steady-state domain wall (DW) motion in the direction opposite to that of the electron flow without Walker Breakdown when a transverse microwave field is applied. This kind of motion is very sensitive to the microwave frequency and can be resonantly enhanced by exciting the domain wall thickness oscillation mode. A one-dimensional analytical model was established to account for the microwave-assisted wall motion. These findings may be helpful for reducing the critical spin-polarized current density and designing DW-based spintronic devices.

  12. Ankle torque control that shifts the center of pressure from heel to toe contributes non-zero sagittal plane angular momentum during human walking.

    Science.gov (United States)

    Gruben, Kreg G; Boehm, Wendy L

    2014-04-11

    A principle objective of human walking is controlling angular motion of the body as a whole to remain upright. The force of the ground on each foot (F) reflects that control, and recent studies show that in the sagittal plane F exhibits a specific coordination between F direction and center-of-pressure (CP) that is conducive to remaining upright. Typical walking involves the CP shifting relative to the body due to two factors: posterior motion of the foot with respect to the hip (stepping) and motion of the CP relative to the foot (foot roll-over). Recent research has also shown how adjusting ankle torque alone to shift CP relative to the foot systematically alters the direction of F, and thus, could play a key role in upright posture and the F measured during walking. This study explores how the CP shifts due to stepping and foot roll-over contribute to the observed F and its role in maintaining upright posture. Experimental walking kinetics and kinematics were combined with a mechanical model of the human to show that variation in F that was not attributable to foot roll-over had systematic correlation between direction and CP that could be described by an intersection point located near the center-of-mass. The findings characterize a component of walking motor control, describe how typical foot roll-over contributes to postural control, and provide a rationale for the increased fall risk observed in individuals with atypical ankle muscle function. PMID:24524989

  13. Ankle pain

    Science.gov (United States)

    Pain - ankle ... Ankle pain is often due to an ankle sprain. An ankle sprain is an injury to the ligaments, which ... the joint. In addition to ankle sprains, ankle pain can be caused by: Damage or swelling of ...

  14. Ankle Cheilectomy

    Science.gov (United States)

    ... removes a bone spur from the talus or tibia, which are bones of the ankle joint. X- ... Tendon Rupture Surgery Ankle Arthrodesis Ankle Arthroscopy Ankle Fracture Surgery Bulk Allograft Transplantation for Osteochondral Lesions of ...

  15. Ankle Fractures

    Science.gov (United States)

    ... during a car accident Symptoms Because a severe ankle sprain can feel the same as a broken ankle, ... the ligament -- this is also known as high ankle sprain. Depending on how unstable the ankle is, these ...

  16. Ankle arthroscopy

    Science.gov (United States)

    ... Failure of repair to heal Weakness of the ankle Injury to tendon, blood vessel, or nerve Before the ... A.M. Editorial team. Related MedlinePlus Health Topics Ankle Injuries and Disorders Endoscopy Browse the Encyclopedia A.D. ...

  17. Fractures of the ankle Fractures of the ankle

    OpenAIRE

    Taser, Omer; Goksan, Alp; Asik, Mehmet

    2004-01-01

    In this study 151 patients who were operated for the ankle fracture between 1980 and 1988 and also 277 patients who were conservatively treated between January 1987 and April 1988 in Orthopaedics and Traumatology Department of Istanbul Medical Faculty were taken into consideration. It has been seen that ankle fractures which comprised a high percent (%1.6) in all patients who applied to our emergency department. We showed that the ratio of patients who had operative treatment had been steadi...

  18. Ankle sprain (image)

    Science.gov (United States)

    An ankle sprain is a common injury to the ankle. The most common way the ankle is injured is when ... swelling, inflammation, and bruising around the ankle. An ankle sprain injury may take a few weeks to many ...

  19. Chronic Ankle Instability

    Science.gov (United States)

    ... ankle surgeon will ask you about any previous ankle injuries and instability. Then s/he will examine your ankle ... Weak ankles may be a result of previous ankle injuries, but in some cases they are a congenital ( ...

  20. Sprained Ankles

    Science.gov (United States)

    ... Body I think my child has sprained her ankle. How can I tell for sure? Sprains are injuries to the ligaments that connect bones ... away before the ligament is injured. Types of Sprains In young children, the ankle is the most commonly sprained joint, followed by ...

  1. Ankle replacement

    Science.gov (United States)

    ... Ankle weakness, stiffness, or instability Loosening of the artificial joint over time Skin not healing after surgery Nerve damage Blood vessel damage Bone break during surgery Dislocation of the ...

  2. Ankle replacement

    Science.gov (United States)

    ... to the cut bony surfaces. A special glue/bone cement may be used to hold them in place. A piece of plastic is then inserted between the two metal parts. Screws maybe placed to stabilize your ankle. The surgeon ...

  3. Ankle sprain

    OpenAIRE

    Struijs, Peter AA; Kerkhoffs, Gino MMJ

    2010-01-01

    Injury of the lateral ligament complex of the ankle joint occurs in about one in 10,000 people a day, accounting for a quarter of all sports injuries. Pain may be localised to the lateral side of the ankle.Residual complaints include joint instability, stiffness, and intermittent swelling, and are more likely to occur after more extensive cartilage damage.Recurrent sprains can add new damage and increase the risk of long-term degeneration of the joint.

  4. Assessment of a portable device for the quantitative measurement of ankle joint stiffness in spastic individuals

    DEFF Research Database (Denmark)

    Lorentzen, Jakob; Grey, Michael J; Geertsen, Svend Sparre;

    2012-01-01

    Neurokinetics RA1 Ridgidity Analyzer to measure stiffness of the ankle joint in 46 controls, 14 spinal cord injured (SCI) and 23 multiple sclerosis (MS) participants. METHODS: Ankle stiffness measures were made twice by two raters, at speeds above and below the expected stretch reflex threshold. Ankle torque...

  5. Invariant ankle moment patterns when walking with and without a robotic ankle exoskeleton

    OpenAIRE

    Kao, Pei-Chun; Lewis, Cara L.; Ferris, Daniel P.

    2009-01-01

    To guide development of robotic lower limb exoskeletons, it is necessary to understand how humans adapt to powered assistance. The purposes of this study were to quantify joint moments while healthy subjects adapted to a robotic ankle exoskeleton and to determine if the period of motor adaptation is dependent on the magnitude of robotic assistance. The pneumatically-powered ankle exoskeleton provided plantar flexor torque controlled by the wearer’s soleus electromyography (EMG). Eleven naïve ...

  6. Ankle clonus

    OpenAIRE

    Fareedy, Shoaib Bilal; Pathak, Ranjan

    2015-01-01

    Key Clinical Message Clonus is a series of involuntary, rhythmic, muscular contractions, and relaxations. It may be caused by interruption of the upper motor neuron fibers such as stroke, multiple sclerosis, or by metabolic alterations such as severe hepatic failure or serotonin syndrome. We present a video case of impressive left ankle clonus in a patient with old right middle cerebral artery stroke.

  7. Design of a simple, lightweight, passive-elastic ankle exoskeleton supporting ankle joint stiffness

    Science.gov (United States)

    Kim, Seyoung; Son, Youngsu; Choi, Sangkyu; Ham, Sangyong; Park, Cheolhoon

    2015-09-01

    In this study, a passive-elastic ankle exoskeleton (PEAX) with a one-way clutch mechanism was developed and then pilot-tested with vertical jumping to determine whether the PEAX is sufficiently lightweight and comfortable to be used in further biomechanical studies. The PEAX was designed to supplement the function of the Achilles tendon and ligaments as they passively support the ankle torque with their inherent stiffness. The main frame of the PEAX consists of upper and lower parts connected to each other by tension springs (N = 3) and lubricated hinge joints. The upper part has an offset angle of 5° with respect to the vertical line when the springs are in their resting state. Each spring has a slack length of 8 cm and connects the upper part to the tailrod of the lower part in the neutral position. The tailrod freely rotates with low friction but has a limited range of motion due to the stop pin working as a one-way clutch. Because of the one-way clutch system, the tension springs store the elastic energy only due to an ankle dorsiflexion when triggered by the stop pin. This clutch mechanism also has the advantage of preventing any inconvenience during ankle plantarflexion because it does not limit the ankle joint motion during the plantarflexion phase. In pilot jumping tests, all of the subjects reported that the PEAX was comfortable for jumping due to its lightweight (approximately 1 kg) and compact (firmly integrated with shoes) design, and subjects were able to nearly reach their maximum vertical jump heights while wearing the PEAX. During the countermovement jump, elastic energy was stored during dorsiflexion by spring extension and released during plantarflexion by spring restoration, indicating that the passive spring torque (i.e., supportive torque) generated by the ankle exoskeleton partially supported the ankle joint torque throughout the process.

  8. Ankle sprain - aftercare

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000574.htm Ankle sprain - aftercare To use the sharing features on this ... help them move in the right ways. An ankle sprain occurs when the ligaments in your ankle are ...

  9. Design of a portable hydraulic ankle-foot orthosis.

    Science.gov (United States)

    Neubauer, Brett C; Nath, Jonathan; Durfee, William K

    2014-01-01

    Small-scale hydraulics is ideal for powered human assistive devices including powered ankle foot orthoses because a large torque can be generated with an actuator that is small and light. A portable hydraulic ankle foot orthosis has been designed and is undergoing preliminary prototyping and engineering bench test evaluation. The device provides 90 Nm of ankle torque and has an operating pressure of 138 bar (2,000 psi). The battery-operated hydraulic power supply weighs about 3 kg and is worn at the waist. The ankle component weighs about 1.2 Kg and connects to the power supply with two hoses. Performance simulation and preliminary bench testing suggests that the device could be useful in certain rehabilitation applications. PMID:25570175

  10. Modulation of ankle stiffness during postural sway.

    Science.gov (United States)

    Lang, Christopher B; Kearney, Robert E

    2014-01-01

    Ankle stiffness is a nonlinear, time-varying system which contributes to the control of human upright stance. This study sought to examine the nature of the contribution of stiffness to postural control by determining how intrinsic and reflex stiffnesses varied with sway. Subjects were instructed to stand quietly on a bilateral electro-hydraulic actuator while perturbations were applied about the ankle. Subjects performed three types of trials: normal stance, forward lean, and backward lean. Position, torque, and EMGs from the tibialis anterior and triceps surae were recorded. Background torque, intrinsic stiffness and reflex stiffness were calculated for each perturbation. Intrinsic and reflex stiffnesses were heavily modulated by postural sway. Moreover, they were modulated in a complimentary manner; intrinsic stiffness was lowest when reflex gain was highest, and vice versa. These findings suggest that intrinsic stiffness is modulated simultaneously with reflex stiffness to optimize the control of balance. PMID:25570884

  11. Ankle Sprain Treatment

    Science.gov (United States)

    ... Ankle Sprain Treatment Page Content Article Body Acute ankle and foot injuries are common in athletes and other active young ... Phase I treatment involves resting and protecting the ankle to permit healing, to prevent further injury, and to control pain and swelling. Rest, protection ( ...

  12. Assessment of Ankle Injuries

    Science.gov (United States)

    Mai, Nicholas; Cooper, Leslie

    2009-01-01

    School nurses are faced with the challenge of identifying and treating ankle injuries in the school setting. There is little information guiding the assessment and treatment of these children when an injury occurs. It is essential for school nurses to understand ankle anatomy, pathophysiology of the acute ankle injury, general and orthopedic…

  13. Ottawa ankle rules.

    OpenAIRE

    Stiell, I.

    1996-01-01

    The Ottawa ankle rule project demonstrated that more than 95% of patients with ankle injuries had radiographic examinations but that 85% of the films showed no fractures. A group of Ottawa emergency physicians developed two rules to identify clinically important fractures of the malleoli and the midfoot. Use of these rules reduced radiographic examinations by 28% for the ankle and 14% for the foot.

  14. Direct torque control of permanent magnet drives

    Energy Technology Data Exchange (ETDEWEB)

    French, C.; Acarnley, P. [Univ. of Newcastle upon Tyne (United Kingdom)

    1995-12-31

    Many permanent magnet motor drives use an open loop form of torque control, based on the assumption that output torque is proportional to applied current. In a practical motor this assumption may not always be correct, due to sub-optimal alignment of magnets, non-uniformity of magnetic material, current sensor non-linearities and current controller limitations. These factors, together with non-optimized current references, can lead to high values of torque ripple and copper loss. This paper describes a method of estimating the electro-magnetic torque from the rate of change of co-energy with respect to position, thus taking account of mutual torque, reluctance torque and saturation effects. The paper shows how the estimator can be used in a direct torque control scheme. The direct torque controller maximizes the torque:copper loss ratio. Implementation of the direct torque controller in a DSP based drive system is described, with steady-state and transient experimental results illustrating the effectiveness of the direct torque control scheme.

  15. Investigation of Motorcycle Steering Torque Components

    Science.gov (United States)

    Cossalter, V.; Lot, R.; Massaro, M.; Peretto, M.

    2011-10-01

    When driving along a circular path, the rider controls a motorcycle mainly by the steering torque. This work addresses an in-depth analysis of the steady state cornering and in particular the decomposition of the motorcycle steering torque in its main components, such as road-tyre forces, gyroscopic torques, centrifugal and gravity effects. A detailed and experimentally validated multibody model of the motorcycle is used herein to analyze the steering torque components at different speeds and lateral accelerations. First the road tests are compared with the numerical results for three different vehicles and then a numerical investigation is carried out to decompose the steering torque. Finally, the effect of longitudinal acceleration and deceleration on steering torque components is presented.

  16. Total ankle joint replacement.

    Science.gov (United States)

    2016-02-01

    Ankle arthritis results in a stiff and painful ankle and can be a major cause of disability. For people with end-stage ankle arthritis, arthrodesis (ankle fusion) is effective at reducing pain in the shorter term, but results in a fixed joint, and over time the loss of mobility places stress on other joints in the foot that may lead to arthritis, pain and dysfunction. Another option is to perform a total ankle joint replacement, with the aim of giving the patient a mobile and pain-free ankle. In this article we review the efficacy of this procedure, including how it compares to ankle arthrodesis, and consider the indications and complications. PMID:26868932

  17. A Novel Direct Torque Control for Induction Machine Drive System with Low Torque And Flux Ripples using XSG

    OpenAIRE

    Souha Boukadida; Soufien Gdaim; Abdellatif Mtibaa

    2014-01-01

    The conventional Direct Torque Control (DTC) is known to produce a quick and robust response in AC drives. However, during steady state, stator flux and electromagnetic torque which results in incorrect speed estimations and acoustical noise. A modified Direct Torque Control (DTC) by using Space Vector Modulation (DTC-SVM) for induction machine is proposed in this paper. Using this control strategy, the ripples introduced in torque and flux are reduced. This paper presents a novel approach to...

  18. Large amplitude oscillation of magnetization in spin-torque oscillator stabilized by field-like torque

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, Tomohiro, E-mail: tomohiro-taniguchi@aist.go.jp; Kubota, Hitoshi; Imamura, Hiroshi [National Institute of Advanced Industrial Science and Technology (AIST), Spintronics Research Center, Tsukuba 305-8568 (Japan); Tsunegi, Sumito [Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Ave. A. Fresnel, Palaiseau (France)

    2015-05-07

    Oscillation frequency of spin torque oscillator with a perpendicularly magnetized free layer and an in-plane magnetized pinned layer is theoretically investigated by taking into account the field-like torque. It is shown that the field-like torque plays an important role in finding the balance between the energy supplied by the spin torque and the dissipation due to the damping, which results in a steady precession. The validity of the developed theory is confirmed by performing numerical simulations based on the Landau-Lifshitz-Gilbert equation.

  19. 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 ...

  20. How to Tape an Ankle

    Science.gov (United States)

    ... to Tape a Toe How to Stretch Your Ankle After A Sprain How to Strengthen Your Ankle After a Sprain How to Prepare for Orthopaedic Foot or Ankle Surgery: Part III How to Prepare for Orthopaedic ...

  1. Ankle Sprains. A Round Table.

    Science.gov (United States)

    Physician and Sportsmedicine, 1986

    1986-01-01

    Types of ankle sprains, surgical versus nonsurgical treatment, tape versus brace for support, rehabilitation, exercise, and prevention of ankle sprains are discussed by a panel of experts. An acute ankle taping technique is illustrated. (MT)

  2. Understanding acute ankle ligamentous sprain injury in sports

    Directory of Open Access Journals (Sweden)

    Fong Daniel TP

    2009-07-01

    Full Text Available Abstract This paper summarizes the current understanding on acute ankle sprain injury, which is the most common acute sport trauma, accounting for about 14% of all sport-related injuries. Among, 80% are ligamentous sprains caused by explosive inversion or supination. The injury motion often happens at the subtalar joint and tears the anterior talofibular ligament (ATFL which possesses the lowest ultimate load among the lateral ligaments at the ankle. For extrinsic risk factors to ankle sprain injury, prescribing orthosis decreases the risk while increased exercise intensity in soccer raises the risk. For intrinsic factors, a foot size with increased width, an increased ankle eversion to inversion strength, plantarflexion strength and ratio between dorsiflexion and plantarflexion strength, and limb dominance could increase the ankle sprain injury risk. Players with a previous sprain history, players wearing shoes with air cells, players who do not stretch before exercising, players with inferior single leg balance, and overweight players are 4.9, 4.3, 2.6, 2.4 and 3.9 times more likely to sustain an ankle sprain injury. The aetiology of most ankle sprain injuries is incorrect foot positioning at landing – a medially-deviated vertical ground reaction force causes an explosive supination or inversion moment at the subtalar joint in a short time (about 50 ms. Another aetiology is the delayed reaction time of the peroneal muscles at the lateral aspect of the ankle (60–90 ms. The failure supination or inversion torque is about 41–45 Nm to cause ligamentous rupture in simulated spraining tests on cadaver. A previous case report revealed that the ankle joint reached 48 degrees inversion and 10 degrees internal rotation during an accidental grade I ankle ligamentous sprain injury during a dynamic cutting trial in laboratory. Diagnosis techniques and grading systems vary, but the management of ankle ligamentous sprain injury is mainly conservative

  3. The foot and ankle

    International Nuclear Information System (INIS)

    Imaging of the foot and ankle can be difficult because of the complex anatomy. Familiarity with the bony and ligamentous anatomy is essential for proper evaluation of radiographic findings. Therefore, pertinent anatomy is discussed as it applies to specific injuries. Special views, tomography, arthrography, and other techniques may be indicated for complete evaluation of foot and ankle trauma

  4. Ankle sprain - slideshow

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/presentations/100209.htm Ankle sprain - Series To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ... 4 out of 4 Normal anatomy Overview The ankle joint connects the foot with the leg. The ...

  5. An Examination of the Stretch-Shortening Cycle of the Dorsiflexors and Evertors in Uninjured and Functionally Unstable Ankles

    OpenAIRE

    Porter, Gary K.; Kaminski, Thomas W.; Hatzel, Brian; Powers, Michael E.; Horodyski, MaryBeth

    2002-01-01

    Objective: To determine if there were differences in concentric peak torque/body-weight (PT/BW) ratios and concentric time to peak torque (TPT) of the dorsiflexors and evertors in uninjured and functionally unstable ankles using a stretch-shortening cycle (SSC) protocol on an isokinetic dynamometer.

  6. Update on anterior ankle impingement

    OpenAIRE

    Vaseenon, Tanawat; Amendola, Annunziato

    2012-01-01

    Anterior ankle impingement results from an impingement of the ankle joint by a soft tissue or osteophyte formation at the anterior aspect of the distal tibia and talar neck. It often occurs secondary to direct trauma (impaction force) or repetitive ankle dorsiflexion (repetitive impaction and traction force). Chronic ankle pain, swelling, and limitation of ankle dorsiflexion are common complaints. Imaging is valuable for diagnosis of the bony impingement but not for the soft tissue impingemen...

  7. Arthrography of the ankle

    International Nuclear Information System (INIS)

    As part of a clinical prospective investigation 102 patients with fresh ankle injuries underwent ankle arthrography and surgery for rupture of the lateral ligaments of the ankle. Three hypotheses concerning the improvement of the arthrographic diagnosis of rupture of the calcaneofibular ligament were tested. Two were rejected. Improvement in the diagnostic specificity was possible by combining arthrography with a stress inversion test, but the sensitivity of this combination was low. It was demonstrated that absence of peroneus sheath filling was a better diagnostic sign with good rather than with poor recess filling. (Auth.)

  8. Arthrography of the ankle

    International Nuclear Information System (INIS)

    The contribution of artrography in the diagnosis of acute ligaments injuries of the ankle is discussed. The technique of examination is described. An anatomic review, diagnostic elements and the proceeding are presented emphasizing the lateral ligaments. (M.A.C.)

  9. Ankle fracture - aftercare

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000548.htm Ankle fracture - aftercare To use the sharing features on this ... Sit with your foot elevated higher than your knee at least 4 times a day Apply an ...

  10. Ankle muscle strength discriminates fallers from non-fallers

    Science.gov (United States)

    Cattagni, Thomas; Scaglioni, Gil; Laroche, Davy; Van Hoecke, Jacques; Gremeaux, Vincent; Martin, Alain

    2014-01-01

    It is well known that center of pressure (CoP) displacement correlates negatively with the maximal isometric torque (MIT) of ankle muscles. This relationship has never been investigated in elderly fallers (EF). The purpose of this study was thus to analyze the relationship between the MIT of ankle muscles and CoP displacement in upright stance in a sample aged between 18 and 90 years old that included EF. The aim was to identify a threshold of torque below which balance is compromised. The MIT of Plantar flexors (PFs) and dorsal flexors (DFs) and CoP were measured in 90 volunteers: 21 healthy young adults (YA) (age: 24.1 ± 5.0), 12 healthy middle-aged adults (MAA) (age: 50.2 ± 4.5), 27 healthy elderly non-fallers (ENF) (age: 75.5 ± 7.0) and 30 EF (age: 78.8 ± 6.7). The MIT of PF and DF were summed to obtain the overall maximal ankle muscle strength. Body weight and height were used to normalize MIT (nMIT) and CoP (nCoP), respectively. nCoP correlated negatively with nMIT. 90% of EF generated an nMIT 3.1 N·m·kg−1. The relationship between nMIT and nCoP implies that ankle muscle weakness contributes to increased postural instability and the risk of falling. We observed that below the threshold of 3.1 N·m·kg−1, postural stability was dramatically diminished and balance was compromised. Our results suggest that measuring ankle torque could be used in routine clinical practice to identify potential fallers. PMID:25566068

  11. Neuromusculoskeletal torque-generation process has a large destabilizing effect on the control mechanism of quiet standing.

    Science.gov (United States)

    Masani, Kei; Vette, Albert H; Kawashima, Noritaka; Popovic, Milos R

    2008-09-01

    The delay of the sensory-motor feedback loop is a destabilizing factor within the neural control mechanism of quiet standing. The purposes of this study were 1) to experimentally identify the neuromusculoskeletal torque-generation process during standing posture and 2) to investigate the effect of the delay induced by this system on the control mechanism of balance during quiet standing. Ten healthy adults participated in this study. The ankle torque, ankle angle, and electromyograms from the right lower leg muscles were measured. A ground-fixed support device was used to support the subject at his/her knees, without changing the natural ankle angle during quiet standing. Each subject was asked to mimic the ankle torque fluctuation by exerting voluntary ankle extension while keeping the supported standing posture. Using the rectified soleus electromyogram as the input and the ankle torque as the output, a critically damped, second-order system (twitch contraction time of 0.152 +/- 0.027 s) successfully described the dynamics of the torque-generation process. According to the performed Bode analysis, the phase delay induced by this torque-generation process in the frequency region of spontaneous body sway during quiet standing was considerably large, corresponding to an effective time delay of about 200 to 380 ms. We compared the stability of the balance control system with and without the torque-generation process and demonstrated that a much smaller number of gain combinations can stabilize the model with the torque-generation process than without it. We concluded that the phase delay induced by the torque-generation process is a more destabilizing factor in the control mechanism of quiet standing than previously assumed, which restricts the control strategies that can stabilize the entire system. PMID:18596181

  12. Ankle injuries in basketball players.

    Science.gov (United States)

    Leanderson, J; Nemeth, G; Eriksson, E

    1993-01-01

    We carried out a retrospective study of the frequency of ankle sprains in basketball players. A questionnaire about previous ankle injuries, time off after such injuries, current ankle problems, personal data, number of practice hours and the use of prophylactic measures was sent out to 102 basketball players in a second division league in Sweden. Ninety-six players answered. 92% of them had suffered an ankle sprain while playing basketball, and of these 83% reported repeated sprains of one ankle. In the last two seasons, 78% of the players had injured at least one ankle. The injury frequency in the investigation was 5.5 ankle injuries per 1000 activity hours. 22% of the players used some kind of prophylactic support of their ankle joints. Because of the great number of ankle sprains and the disability in terms of time away from sports that they cause, prevention of these injuries is essential. PMID:8536029

  13. Design and Control of an Active Electrical Knee and Ankle Prosthesis

    OpenAIRE

    Sup, Frank; Varol, Huseyin Atakan; Mitchell, Jason; Withrow, Thomas; Goldfarb, Michael

    2008-01-01

    This paper presents an overview of the design and control of an electrically powered knee and ankle prosthesis. The prosthesis design incorporates two motor-driven ball screw units to drive the knee and ankle joints. A spring in parallel with the ankle motor unit is employed to decrease the power consumption and increase the torque output for a given motor size. The device’s sensor package includes a custom load cell to measure the sagittal socket interface moment above the knee joint, a cust...

  14. What Is a Foot and Ankle Surgeon?

    Science.gov (United States)

    ... Foot & Ankle Surgeon? A A A | Print | Share What is a Foot & Ankle Surgeon? Foot and ankle ... of conditions that affect people of every age. What education has a foot and ankle surgeon received? ...

  15. Analysis of torque-current characteristic of brushless DC motor driven by three-phase H-bridge

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Presents the simulation and analysis of the steady state characteristic of a brushless DC motor studies the torque-current characteristic of the motor as well and discusses the design of a current-measure circuit for torque controlling.

  16. Sporadically Torqued Accretion Disks Around Black Holes

    CERN Document Server

    Garofalo, D; Garofalo, David; Reynolds, Christopher S.

    2005-01-01

    The assumption that black hole accretion disks possess an untorqued inner boundary, the so-called zero torque boundary condition, has been employed by models of black hole disks for many years. However, recent theoretical and observational work suggests that magnetic forces may appreciably torque the inner disk. This raises the question of the effect that a time-changing magnetic torque may have on the evolution of such a disk. In particular, we explore the suggestion that the ``Deep Minimum State'' of the Seyfert galaxy MCG--6-30-15 can be identified as a sporadic inner disk torquing event. This suggestion is motivated by detailed analyses of changes in the profile of the broad fluorescence iron line in XMM-Newton spectra. We find that the response of such a disk to a torquing event has two phases; an initial damming of the accretion flow together with a partial draining of the disk interior to the torque location, followed by a replenishment of the inner disk as the system achieves a new (torqued) steady-st...

  17. Contractile and Elastic Ankle Joint Muscular Properties in Young and Older Adults

    OpenAIRE

    Hasson, Christopher J.; Miller, Ross H; Caldwell, Graham E.

    2011-01-01

    The purpose of this study was to investigate age-related differences in contractile and elastic properties of both dorsi- (DF) and plantarflexor (PF) muscles controlling the ankle joint in young and older adults. Experimental data were collected while twelve young and twelve older male and female participants performed maximal effort isometric and isovelocity contractions on a dynamometer. Equations were fit to the data to give torque-angle (Tθ) and torque-angular velocity (Tω) relations. Mus...

  18. Ankle ligament injuries

    Directory of Open Access Journals (Sweden)

    Per A.F.H. Renström

    1998-06-01

    Full Text Available Acute ankle ligament sprains are common injuries. The majority of these occur during athletic participation in the 15 to 35 year age range. Despite the frequency of the injury, diagnostic and treatment protocols have varied greatly. Lateral ligament complex injuries are by far the most common of the ankle sprains. Lateral ligament injuries typically occur during plantar flexion and inversion, which is the position of maximum stress on the anterotalofibular liagment (ATFL. For this reason, the ATFL is the most commonly torn ligament during an inversion injury. In more severe inversion injuries the calcaneofibular (CFL, posterotalofibular (PTFL and subtalar ligament can also be injured. Most acute lateral ankle ligament injuries recover quickly with nonoperative management. The treatment program, called "functional treatment," includes application of the RICE principle (rest, ice, compression, and elevation immediately after the injury, a short period of immobilization and protection with an elastic or inelastic tape or bandage, and early motion exercises followed by early weight bearing and neuromuscular ankle training. Proprioceptive training with a tilt board is commenced as soon as possible, usually after 3 to 4 weeks. The purpose is to improve the balance and neuromuscular control of the ankle. Sequelae after ankle ligament injuries are very common. As much as 10% to 30% of patients with a lateral ligament injury may have chronic symptoms. Symptoms usually include persistent synovitis or tendinitis, ankle stiffness, swelling, and pain, muscle weakness, and frequent giving-way. A well designed physical therapy program with peroneal strengthening and proprioceptive training, along with bracing and/or taping can alleviate instability problems in most patients. For cases of chronic instability that are refractory to bracing and external support, surgical treatment can be explored. If the chronic instability is associated with subtalar instability

  19. The effects of a strategic strength resistance exercise program on the isokinetic muscular function of the ankle.

    Science.gov (United States)

    Jeon, Kyoung-Kyu; Kim, Tae-Young; Lee, Sang-Ho

    2015-10-01

    [Purpose] The purpose of this study was to investigate the effects of a strategic strength resistance exercise program on the isokinetic muscular function of the ankle joint. [Subjects] This study included 22 males in their twenties who were diagnosed with functional injury of the ankle joint. [Methods] To strengthen plantar flexion and dorsiflexion of the ankle joint, 8 weeks of weight, resistance band, and plyometric training, and training using props were performed. [Results] A medical examination by interview indicated that pain, swelling, instability, running, and support capacity of the ankle joint significantly improved with the strategic strength resistance exercise program. For the isokinetic peak torque of the ankles, significant differences were observed in right plantar flexion and bilateral dorsiflexion. [Conclusion] The strategic strength resistance exercise program is highly recommended for the functional stability of the ankle joint. Efficient exercise therapy is useful for muscle damage prevention, muscle strengthening, and functional interventions. PMID:26644696

  20. The effects of a strategic strength resistance exercise program on the isokinetic muscular function of the ankle

    Science.gov (United States)

    Jeon, Kyoung-Kyu; Kim, Tae-Young; Lee, Sang-Ho

    2015-01-01

    [Purpose] The purpose of this study was to investigate the effects of a strategic strength resistance exercise program on the isokinetic muscular function of the ankle joint. [Subjects] This study included 22 males in their twenties who were diagnosed with functional injury of the ankle joint. [Methods] To strengthen plantar flexion and dorsiflexion of the ankle joint, 8 weeks of weight, resistance band, and plyometric training, and training using props were performed. [Results] A medical examination by interview indicated that pain, swelling, instability, running, and support capacity of the ankle joint significantly improved with the strategic strength resistance exercise program. For the isokinetic peak torque of the ankles, significant differences were observed in right plantar flexion and bilateral dorsiflexion. [Conclusion] The strategic strength resistance exercise program is highly recommended for the functional stability of the ankle joint. Efficient exercise therapy is useful for muscle damage prevention, muscle strengthening, and functional interventions. PMID:26644696

  1. Ankle Fractures Often Not Diagnosed

    Science.gov (United States)

    ... Not Diagnosed A A A | Print | Share Ankle Fractures Often Not Diagnosed Long-term complications result from ... patients: Total ankle replacements--similar to hip and knee replacements--were once reserved for geriatric patients but ...

  2. Doctor, I sprained my ankle.

    Science.gov (United States)

    How, Choon How; Tan, Ken Jin

    2014-10-01

    Ankle sprains constitute the majority of ankle injuries, and result in pain, limited mobility/exercise and loss of school/work days. Ankle sprains involve at least one of the ankle ligaments and range from a micro tear to complete tear of the ligament or group of ligaments. The most common mechanism of ankle sprains is inversion stress of a plantar-flexed foot, while the most frequently injured ligament is the anterior talofibular ligament. The attending clinician needs to stratify the risk of fracture through history-taking and physical examination, manage the pain, assess long‑term complications and provide certification for rest and recovery. The Ottawa ankle rules may be useful. Graduated exercises to maintain the ankle's range of motion should be started early, after the resolution of initial pain and swelling. The risk of recurrent ankle injuries is often a combination of both mechanical and functional disabilities. PMID:25631892

  3. Reflex ankle stiffness is inversely correlated with natural body sway.

    Science.gov (United States)

    Julien, Brianna L; Bendrups, Andrew P

    2016-02-01

    We aimed to determine whether effective ankle stiffness (EAS), measured during slow unperceived perturbations of stance, is related to natural anterior-posterior body sway. Because the perturbations are not perceived, any neural component of the response to perturbation is assumed to be "reflex", in the broad sense of an involuntary response to a stimulus. Subjects stood on a force platform for three 10-min trials. EAS was obtained from the average slope (Δτ/Δα) of the relation between ankle torque (τ) and ankle angle (α), recorded during repeated perturbations delivered at the waist by a weak spring. EAS was normalised using the subject's "load stiffness" (LS), calculated from mass (m) and height (h) above the ankle joint (m·g·h). Sway was obtained from fluctuations in ankle angle prior to perturbation. Variation in EAS and sway between subjects provided spread of data for correlation. There were no significant changes in EAS or sway across trials. All subjects had higher EAS than LS and mean EAS (1124Nm/rad) was significantly greater (pinverted pendulum with a stiffness of about twice LS and that EAS is largely generated by neural modulation of postural muscles. The inverse correlation between EAS and body sway suggests that the reflex mechanisms responding to perturbation also influence the extent of natural sway. PMID:27004645

  4. X-Ray Exam: Ankle

    Science.gov (United States)

    ... Tropical Delight: Melon Smoothie Pregnant? Your Baby's Growth X-Ray Exam: Ankle KidsHealth > For Parents > X-Ray Exam: Ankle Print A A A Text Size ... español Radiografía: tobillo What It Is An ankle X-ray is a safe and painless test that uses ...

  5. Estimations of relative effort during sit-to-stand increase when accounting for variations in maximum voluntary torque with joint angle and angular velocity.

    Science.gov (United States)

    Bieryla, Kathleen A; Anderson, Dennis E; Madigan, Michael L

    2009-02-01

    The main purpose of this study was to compare three methods of determining relative effort during sit-to-stand (STS). Fourteen young (mean 19.6+/-SD 1.2 years old) and 17 older (61.7+/-5.5 years old) adults completed six STS trials at three speeds: slow, normal, and fast. Sagittal plane joint torques at the hip, knee, and ankle were calculated through inverse dynamics. Isometric and isokinetic maximum voluntary contractions (MVC) for the hip, knee, and ankle were collected and used for model parameters to predict the participant-specific maximum voluntary joint torque. Three different measures of relative effort were determined by normalizing STS joint torques to three different estimates of maximum voluntary torque. Relative effort at the hip, knee, and ankle were higher when accounting for variations in maximum voluntary torque with joint angle and angular velocity (hip=26.3+/-13.5%, knee=78.4+/-32.2%, ankle=27.9+/-14.1%) compared to methods which do not account for these variations (hip=23.5+/-11.7%, knee=51.7+/-15.0%, ankle=20.7+/-10.4%). At higher velocities, the difference in calculating relative effort with respect to isometric MVC or incorporating joint angle and angular velocity became more evident. Estimates of relative effort that account for the variations in maximum voluntary torque with joint angle and angular velocity may provide higher levels of accuracy compared to methods based on measurements of maximal isometric torques. PMID:17720539

  6. Footballer's ankle: a case report

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ Footballer' s ankle is anterior bony spur or anterior impingement symptom of the ankle with anterior ankle pain, limited and painful dorsiflexion. The cause is commonly seen in athletes and dancers, and is probably due to repetitive minor trauma. The condition was firstly described by Morris;1 McMurray2 reported good results from excision of the spurs, naming it footballer's ankle. Opening resection of osteophytes of the anterior tibial and superior talar is an effective treatment for anterior impingement of the ankle.

  7. Ankle Injuries and Disorders

    Science.gov (United States)

    ... are sprains and fractures. A sprain is an injury to the ligaments. It may take a few weeks to many months to heal completely. A fracture is a break in a bone. You can also ... your joints. Ankle sprains and fractures are common sports injuries.

  8. Advanced Torque Control

    OpenAIRE

    Fritzsche, C; Deunow, H.-P.

    2008-01-01

    In the chapter we discussed a control approach for torque control of gasoline engines. Because of several actuating variables and control requirements the process to be controlled is multivariable. The actuating variables are usually bounded and the effects on the engine torque are nonlinear. Hence direct use of the actuator variables for torque control generally produces plenty of problems. The two layer approach described in the chapter allows the application of standard control methods. Th...

  9. Spin Transfer Torques

    OpenAIRE

    Ralph, D. C.; Stiles, M. D.

    2007-01-01

    This tutorial article introduces the physics of spin transfer torques in magnetic devices. We provide an elementary discussion of the mechanism of spin transfer torque, and review the theoretical and experimental progress in this field. Our intention is to be accessible to beginning graduate students. This is the introductory paper for a cluster of "Current Perspectives" articles on spin transfer torques published in volume 320 of the Journal of Magnetism and Magnetic Materials. This article ...

  10. Ankle rehabilitation device with two degrees of freedom and compliant joint

    Science.gov (United States)

    Racu (Cazacu, C.-M.; Doroftei, I.

    2015-11-01

    We propose a rehabilitation device that we intend to be low cost and easy to manufacture. The system will ensure functionality but also have a small dimensions and low mass, considering the physiological dimensions of the foot and lower leg. To avoid injure of the ankle joint, this device is equipped with a compliant joint between the motor and mechanical transmission. The torque of this joint is intended to be adjustable, according to the degree of ankle joint damage. To choose the material and the dimensions of this compliant joint, in this paper we perform the first stress simulation. The minimum torque is calculated, while the maximum torque is given by the preliminary chosen actuator.

  11. Coordination of muscle torques stabilizes upright standing posture: an UCM analysis.

    Science.gov (United States)

    Park, Eunse; Reimann, Hendrik; Schöner, Gregor

    2016-06-01

    The control of upright stance is commonly explained on the basis of the single inverted pendulum model (ankle strategy) or the double inverted pendulum model (combination of ankle and hip strategy). Kinematic analysis using the uncontrolled manifold (UCM) approach suggests, however, that stability in upright standing results from coordinated movement of multiple joints. This is based on evidence that postural sway induces more variance in joint configurations that leave the body position in space invariant than in joint configurations that move the body in space. But does this UCM structure of kinematic variance truly reflect coordination at the level of the neural control strategy or could it result from passive biomechanical factors? To address this question, we applied the UCM approach at the level of muscle torques rather than joint angles. Participants stood on the floor or on a narrow base of support. We estimated torques at the ankle, knee, and hip joints using a model of the body dynamics. We then partitioned the joint torques into contributions from net, motion-dependent, gravitational, and generalized muscle torques. A UCM analysis of the structure of variance of the muscle torque revealed that postural sway induced substantially more variance in directions in muscle torque space that leave the Center of Mass (COM) force invariant than in directions that affect the force acting on the COM. This difference decreased when we decorrelated the muscle torque data by randomizing across time. Our findings show that the UCM structure of variance exists at the level of muscle torques and is thus not merely a by-product of biomechanical coupling. Because muscle torques reflect neural control signals more directly than joint angles do, our results suggest that the control strategy for upright stance involves the task-specific coordination of multiple degrees of freedom. PMID:26879770

  12. Ankle impingement syndromes

    International Nuclear Information System (INIS)

    Soft-tissue and osseous impingement syndromes can be an important cause of chronic ankle pain, particularly in the professional athlete. The classification of ankle impingement syndromes is based to their anatomical location around the tibiotalar joint. The most important impingement syndromes are anterolateral, anterior and posterior impingement with more recent studies describing posteromedial and anteromedial impingement. Usually conventional radiography is the first imaging technique to be performed as it allows assessment of potential bone abnormalities, particularly in anterior and posterior joint compartments. Computed tomography (CT) only plays a role in the assessment of the posterior impingement. Magnetic resonance (MR) imaging is regarded as the modality of choice as it is able to demonstrate both osseous and soft tissue changes, such as bone marrow edema, capsular and ligametous thickening, and localized synovitis. (orig.)

  13. Arthrography of the ankle

    International Nuclear Information System (INIS)

    Arthrography was performed in 105 cases with freshly sprained ankles and signs of rupture of the anterior talofibular ligament. They were subsequently operated upon. The arthrographic films were examined retrospectively to assess the value of different criteria for the differential diagnosis between rupture of the anterior talofibular ligament and combined rupture of this and the calcaneofibular ligament. The diagnostic value of arthrography was found to be high in isolated rupture of the anterior talofibular ligament, and is acceptable in the combined ruptures. (Auth.)

  14. Update on acute ankle sprains.

    Science.gov (United States)

    Tiemstra, Jeffrey D

    2012-06-15

    Ankle sprains are a common problem seen by primary care physicians, especially among teenagers and young adults. Most ankle sprains are inversion injuries to the lateral ankle ligaments, although high sprains representing damage to the tibiofibular syndesmosis are becoming increasingly recognized. Physicians should apply the Ottawa ankle rules to determine whether radiography is needed. According to the Ottawa criteria, radiography is indicated if there is pain in the malleolar or midfoot zone, and either bone tenderness over an area of potential fracture (i.e., lateral malleolus, medial malleolus, base of fifth metatarsal, or navicular bone) or an inability to bear weight for four steps immediately after the injury and in the emergency department or physician's office. Patients with ankle sprain should use cryotherapy for the first three to seven days to reduce pain and improve recovery time. Patients should wear a lace-up ankle support or an air stirrup brace combined with an elastic compression wrap to reduce swelling and pain, speed recovery, and protect the injured ligaments as they become more mobile. Early mobilization speeds healing and reduces pain more effectively than prolonged rest. Pain control options for patients with ankle sprain include nonsteroidal anti-inflammatory drugs, acetaminophen, and mild opioids. Because a previous ankle sprain is the greatest risk factor for an acute ankle sprain, recovering patients should be counseled on prevention strategies. Ankle braces and supports, ankle taping, a focused neuromuscular training program, and regular sport-specific warm-up exercises can protect against ankle injuries, and should be considered for patients returning to sports or other high-risk activities. PMID:22962897

  15. MR imaging of the ankle

    International Nuclear Information System (INIS)

    To define the clinical role of MRI of the ankle joint, a total of 98 patients were investigated. In the evaluation of ligamentous injuy, MRI was inferior to established imaging methods. By contrast, it provided additional therapy-relevant information in the assessment of hemophilic arthropathy, osteochondritis dissecans, and inflammatory and neoplastic diseases of the ankle joint. In the latter conditions, MRI may make other more conventional methods of examining the ankle joint unnecessary. (orig.)

  16. Syndesmosis injuries of the ankle

    OpenAIRE

    Del Buono, Angelo; Florio, Antonietta; Boccanera, Michele Simone; Maffulli, Nicola

    2013-01-01

    Ankle syndesmosis injuries are relatively frequent in sports, especially skiing, ice hockey, and soccer, accounting for 1 %–18 % of all ankle sprains. The evolution is unpredictable: When missed, repeated episodes of ankle instability may predispose to early degenerative changes, and frank osteoarthritis may ensue. Diagnosis is clinical and radiological, but arthroscopy may provide a definitive response, allowing one to address secondary injuries to bone and cartilage. Obvious diastasis needs...

  17. How to Care for a Sprained Ankle

    Science.gov (United States)

    ... to Care for a Sprained Ankle Page Content Ankle sprains are very common injuries. There's a good chance ... to make sure no bones are broken. Most ankle sprains do not require surgery, and minor sprains are ...

  18. Powered ankle-foot prosthesis for the improvement of amputee ambulation.

    Science.gov (United States)

    Au, Samuel K; Herr, Hugh; Weber, Jeff; Martinez-Villalpando, Ernesto C

    2007-01-01

    This paper presents the mechanical design, control scheme, and clinical evaluation of a novel, motorized ankle-foot prosthesis, called MIT Powered Ankle-Foot Prosthesis. Unlike a conventional passive-elastic ankle-foot prosthesis, this prosthesis can provide active mechanical power during the stance period of walking. The basic architecture of the prosthesis is a unidirectional spring, configured in parallel with a force-controllable actuator with series elasticity. With this architecture, the anklefoot prosthesis matches the size and weight of the human ankle, and is also capable of delivering high mechanical power and torque observed in normal human walking. We also propose a biomimetic control scheme that allows the prosthesis to mimic the normal human ankle behavior during walking. To evaluate the performance of the prosthesis, we measured the rate of oxygen consumption of three unilateral transtibial amputees walking at self-selected speeds to estimate the metabolic walking economy. We find that the powered prosthesis improves amputee metabolic economy from 7% to 20% compared to the conventional passive-elastic prostheses (Flex-Foot Ceterus and Freedom Innovations Sierra), even though the powered system is twofold heavier than the conventional devices. This result highlights the benefit of performing net positive work at the ankle joint to amputee ambulation and also suggests a new direction for further advancement of an ankle-foot prosthesis. PMID:18002631

  19. Acute ankle sprain: an update.

    Science.gov (United States)

    Ivins, Douglas

    2006-11-15

    Acute ankle injury, a common musculoskeletal injury, can cause ankle sprains. Some evidence suggests that previous injuries or limited joint flexibility may contribute to ankle sprains. The initial assessment of an acute ankle injury should include questions about the timing and mechanism of the injury. The Ottawa Ankle and Foot Rules provide clinical guidelines for excluding a fracture in adults and children and determining if radiography is indicated at the time of injury. Reexamination three to five days after injury, when pain and swelling have improved, may help with the diagnosis. Therapy for ankle sprains focuses on controlling pain and swelling. PRICE (Protection, Rest, Ice, Compression, and Elevation) is a well-established protocol for the treatment of ankle injury. There is some evidence that applying ice and using nonsteroidal antiinflammatory drugs improves healing and speeds recovery. Functional rehabilitation (e.g., motion restoration and strengthening exercises) is preferred over immobilization. Superiority of surgical repair versus functional rehabilitation for severe lateral ligament rupture is controversial. Treatment using semirigid supports is superior to using elastic bandages. Support devices provide some protection against future ankle sprains, particularly in persons with a history of recurrent sprains. Ankle disk or proprioceptive neuromuscular facilitation exercise regimens also may be helpful, although the literature supporting this is limited. PMID:17137000

  20. van der Waals torque

    Science.gov (United States)

    Esquivel-Sirvent, Raul; Schatz, George

    2014-03-01

    The theory of generalized van der Waals forces by Lifshtz when applied to optically anisotropic media predicts the existence of a torque. In this work we present a theoretical calculation of the van der Waals torque for two systems. First we consider two isotropic parallel plates where the anisotropy is induced using an external magnetic field. The anisotropy will in turn induce a torque. As a case study we consider III-IV semiconductors such as InSb that can support magneto plasmons. The calculations of the torque are done in the Voigt configuration, that occurs when the magnetic field is parallel to the surface of the slabs. The change in the dielectric function as the magnetic field increases has the effect of decreasing the van der Waals force and increasing the torque. Thus, the external magnetic field is used to tune both the force and torque. The second example we present is the use of the torque in the non retarded regime to align arrays of nano particle slabs. The torque is calculated within Barash and Ginzburg formalism in the nonretarded limit, and is quantified by the introduction of a Hamaker torque constant. Calculations are conducted between anisotropic slabs of materials including BaTiO3 and arrays of Ag nano particles. Depending on the shape and arrangement of the Ag nano particles the effective dielectric function of the array can be tuned as to make it more or less anisotropic. We show how this torque can be used in self assembly of arrays of nano particles. ref. R. Esquivel-Sirvent, G. C. Schatz, Phys. Chem C, 117, 5492 (2013). partial support from DGAPA-UNAM.

  1. Proposed Voltage Vector to Optimize Efficiency of Direct Torque Control

    OpenAIRE

    Goh Wee Yen; Ali Monadi; Nik Rumzi Nik Idris; Auzani Jidin; Tole Sutikno

    2014-01-01

    Compared to field-oriented control (FOC) system, direct torque control (DTC) system has gained attractiveness in control drive system because of its simpler control structure and faster dynamic control. However, supplying the drive system with rated flux at light load will decrease the power factor and efficiency of the system. Thus, an optimal flux has been applied during steady-state in order to maximize the efficiency of drive system. But when a torque is suddenly needed, for example durin...

  2. Talofibular compartment of the ankle joint after recent ankle sprain

    International Nuclear Information System (INIS)

    The validity of predicting the condition of the anterior talofibular ligament from the shape of the lateral compartment of the ankle joint was investigated in patients with recent ankle sprain. The diagnostic value of the method was found to be restricted. (Auth.)

  3. A Novel Direct Torque Control for Induction Machine Drive System with Low Torque And Flux Ripples using XSG

    Directory of Open Access Journals (Sweden)

    Souha Boukadida

    2014-12-01

    Full Text Available The conventional Direct Torque Control (DTC is known to produce a quick and robust response in AC drives. However, during steady state, stator flux and electromagnetic torque which results in incorrect speed estimations and acoustical noise. A modified Direct Torque Control (DTC by using Space Vector Modulation (DTC-SVM for induction machine is proposed in this paper. Using this control strategy, the ripples introduced in torque and flux are reduced. This paper presents a novel approach to design and implementation of a high perfromane torque control (DTC-SVM of induction machine using Field Programmable gate array (FPGA.The performance of the proposed control scheme is evaluated through digital simulation using Matlab\\Simulink and Xilinx System Generator. The simulation results are used to verify the effectiveness of the proposed control strategy.

  4. PEAK AND END RANGE ECCENTRIC EVERTOR/CONCENTRIC INVERTOR MUSCLE STRENGTH RATIOS IN CHRONICALLY UNSTABLE ANKLES: COMPARISON WITH HEALTHY INDIVIDUALS

    Directory of Open Access Journals (Sweden)

    Mahmut Komurcu

    2003-09-01

    Full Text Available The aim of this study was to evaluate the alterations in eccentric evertor/concentric invertor strength ratio and their importance in the chronically unstable ankle. Eight patients with chronic ankle instability (CAI and nine healthy individuals participated in this study. Isokinetic concentric and eccentric invertor and evertor muscle strength measurement was carried out at an angular velocity of 120°·sec-1 by measuring maximal force moments (torque during isokinetic ankle inversion and eversion movements. Functionally, evertor/invertor muscle strength ratios (E/I strength ratio were calculated separately based on peak moment and angle-specific moments obtained at 0°, 5°, 10°, 15°, 20° ankle joint angles. Peak and angle-specific eccentric evertor strength values at 0°, 5°, 10°, 15°, 20° were significantly lower in the chronic ankle instability (CAI group. In spite of this, no differences were obtained for peak and angle-specific concentric invertor torque values. Eccentric evertor/concentric invertor strength (Eecc/Icon ratios were also significantly lower in the CAI group, but only at 15° and 20°. Eccentric evertor muscle torque and end range (15°-20° Eecc/Icon strength ratio for the chronically unstable ankle were significantly different from those for the healthy ankle. For this reason, measurements of end range eccentric/concentric strength ratios are more valuable in monitoring chronic ankle injuries and rehabilitation should include not only concentric muscle strengthening but also eccentric muscle strengthening, particularly for the evertor muscles

  5. Ultrasonography of ankle ligaments

    International Nuclear Information System (INIS)

    The lateral collateral ligament of the ankle is a complex of 3 ligaments: The anterior and posterior talofibular ligaments and the calcaneofibular ligament; these ligaments work together to support the lateral aspect of the ankle. The anterior talofibular (ATF) ligament (Fig. 1) runs from the anterior of the talus. The probe is placed in a slightly oblique position from the malleolus toward the forefoot. The ligament is hyperechoic when its fibres are perpendicular to the ultrasound beam (anisotropy artifact is present in ligaments as well as in tendons). It is approximately 2 mm thick and, during examination, must be straight and tight from one insertion point to the other, as seen in Fig. 2. The posterior talofibular (PTF) ligament, which runs from the posterior part of the malleolus to the posterior part of the talus, is difficult to see on US, being partially or sometimes completely hidden by the malleolus. The calcaneofibular ligament forms the middle portion of the lateral collateral ligament. It is tight between the inferior part of the lateral malleolus and the calcaneus, and runs in a slightly posterior oblique direction toward the heel (Fig. 3). The ligament lies on the deep surface of the fibular tendons, forming a hammock to fall deep on the calcaneus surface (Fig. 4). The calcaneofibular ligament is approximately 2-3 nun thick and is hyperechoic in the distal two-thirds only because of the obliquity of the proximal part. When examining this ligament, it is mandatory that the ankle be flexed dorsally; this stretches the ligament so that it can be seen clearly. (author)

  6. Identification of the neural component of torque during manually-applied spasticity assessments in children with cerebral palsy

    OpenAIRE

    Bar-On, Lynn; Desloovere, Kaat; Molenaers, Guy; Harlaar, J.; Kindt, T; Aertbeliën, Erwin

    2014-01-01

    Clinical assessment of spasticity is compromised by the difficulty to distinguish neural from non-neural components of increased joint torque. Quantifying the contributions of each of these components is crucial to optimize the selection of anti-spasticity treatments such as botulinum toxin (BTX). The aim of this study was to compare different biomechanical parameters that quantify the neural contribution to ankle joint torque measured during manually-applied passive stretches to the gastrocs...

  7. Improved Torque Control Performance in Direct Torque Control using Optimal Switching Vectors

    Directory of Open Access Journals (Sweden)

    Muhd Zharif Rifqi Zuber Ahmadi

    2015-02-01

    Full Text Available This paper presents the significant improvement of Direct Torque Control (DTC of 3-phases induction machine using a Cascaded H-Bidge Multilevel Inverter (CHMI. The largest torque ripple and variable switching frequency are known as the major problem founded in DTC of induction motor. As a result, it can diminish the performance induction motor control. Therefore, the conventional 2-level inverter has been replaced with CHMI the in order to increase the performance of the motor either in dynamic or steady-state condition. By using the multilevel inverter, it can produce a more selection of the voltage vectors. Besides that, it can minimize the torque ripple output as well as increase the efficiency by reducing the switching frequency of the inverter. The simulation model of the proposed method has been developed and tested by using Matlab software. Its improvements were also verified via experimental results.

  8. Can Chronic Ankle Instability be Prevented? Rethinking Management of Lateral Ankle Sprains.

    Science.gov (United States)

    Denegar, Craig R.; Miller, Sayers J., III

    2002-01-01

    Investigates whether chronic ankle instability can be prevented, discussing: the relationship between mechanical and functional instability; normal ankle mechanics, sequelae to lateral ankle sprains, and abnormal ankle mechanics; and tissue healing, joint dysfunction, and acute lateral ankle sprain management. The paper describes a treatment model…

  9. Ankle Bracing, Plantar-Flexion Angle, and Ankle Muscle Latencies During Inversion Stress in Healthy Participants

    OpenAIRE

    Kernozek, Thomas; Durall, Christopher J; Friske, Allison; Mussallem, Matthew

    2008-01-01

    Context: Ankle braces may enhance ankle joint proprioception, which in turn may affect reflexive ankle muscle activity during a perturbation. Despite the common occurrence of plantar-flexion inversion ankle injuries, authors of previous studies of ankle muscle latencies have focused on inversion stresses only.

  10. MRI of ankle sprain

    International Nuclear Information System (INIS)

    We reviewed MR (magnetic resonance) studies in 54 patients with a sprained ankle. MR examination was able to depict the following injuries: lateral collateral ligamentous injuries, fluid collection in the peroneal tendon sheath, injury to the peroneal tendon, deltoid ligamentous injuries, the extent of subcutaneous soft tissue swelling, and various kinds of osseous injuries. A total of 21 patients underwent repair or reconstructive surgery to the lateral collateral ligaments, the findings of which were correlated with those on MR examination. MR diagnosis of anterior talofibular ligamentous injury was confirmed in 16/21; the discrepancy could be attributed to remodeling and/or reorganization which progressed during the time lapse between the MR examination and surgery in three, while the misdiagnosis resulted from the difficulty in distinguishing the acute tear from the injured scar in two. The calcaneofibular ligamentous injury was confirmed in 10/12; two false negatives were responsible for the difficulty in delineating its entire length on a single image and/or in differentiating between the attenuated star and the normal calcaneofibular ligament. MR imaging is a useful tool to use in deciding the surgical indication and predicting the prognosis of the patients with ankle sprain. (author)

  11. MRI of ankle sprain

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Gen [Dokkyo Univ., Mibu, Tochigi (Japan). School of Medicine

    1995-06-01

    We reviewed MR (magnetic resonance) studies in 54 patients with a sprained ankle. MR examination was able to depict the following injuries: lateral collateral ligamentous injuries, fluid collection in the peroneal tendon sheath, injury to the peroneal tendon, deltoid ligamentous injuries, the extent of subcutaneous soft tissue swelling, and various kinds of osseous injuries. A total of 21 patients underwent repair or reconstructive surgery to the lateral collateral ligaments, the findings of which were correlated with those on MR examination. MR diagnosis of anterior talofibular ligamentous injury was confirmed in 16/21; the discrepancy could be attributed to remodeling and/or reorganization which progressed during the time lapse between the MR examination and surgery in three, while the misdiagnosis resulted from the difficulty in distinguishing the acute tear from the injured scar in two. The calcaneofibular ligamentous injury was confirmed in 10/12; two false negatives were responsible for the difficulty in delineating its entire length on a single image and/or in differentiating between the attenuated star and the normal calcaneofibular ligament. MR imaging is a useful tool to use in deciding the surgical indication and predicting the prognosis of the patients with ankle sprain. (author)

  12. Sports Injuries to the Foot and Ankle

    Science.gov (United States)

    ... FootNotes Newsletter Current Issue Archive Subscribe Home » Foot & Ankle Conditions » Sports Injuries to the Foot and Ankle A A A | ... page. Please enable Javascript in your browser. Sports Injuries to the Foot and Ankle Depending on the sport, your feet and ankles ...

  13. Inversion injury biomechanics in functional ankle instability: a cadaver study of simulated gait.

    Science.gov (United States)

    Konradsen, Lars; Voigt, Michael

    2002-12-01

    The purpose of this study was to test pathogenetic models for the "unprovoked" ankle inversion injuries seen in functional ankle unstable subjects. The consequence of spatial mal-alignment of the ankle/foot complex on the risk of producing an ankle inversion torque at heel-strike and during swing-phase follow through was analyzed in cadaver simulations. Heel-strike was simulated using a 5 degrees of freedom rig in a material testing machine. A set-up capable of accelerating lower limb specimens towards a support surface simulated swing-phase follow through. Joint excursions were monitored with flexible wire goniometers. The unloaded ankle/foot complex was placed in increasing positions of talar and subtalar joint excursions. The consequences of these settings on the behavior of the ankle/foot complex at heel-strike and when the lateral part of the foot "caught" the ground during swing-phase follow through were monitored. An inversion torque at heel-strike was first seen when the unloaded foot was set in positions exceeding 30 degrees of inversion combined with full plantar flexion and 10 degrees of internal tibial rotation. A collision between the lateral border of a 20 degrees inverted, but otherwise neutral ankle/foot complex and the ground surface during swing-phase follow through forced the foot into the full limit of inversion, plantar flexion and internal tibial rotation measurable in this set-up. Clinical consequence: The study showed that the foot/ankle complex exhibits a high degree of intrinsic stability at heel-strike. The foot will thus stabilize itself and move into normal eversion at the beginning of the stance-phase even though it is set to the ground in a substantial degree of mal-alignment. In contrast, the swing-phase collision model provides a link that can connect the small deficits in inversion angle awareness measured in chronic functional ankle unstable subjects with an increased risk in this group of sustaining ankle inversion injuries. PMID

  14. High Performance Direct Torque Control of Induction Motor Drives Using Space Vector Modulation

    Directory of Open Access Journals (Sweden)

    S. Allirani

    2010-11-01

    Full Text Available This paper presents a simple approach to design and implement Direct Torque Control technique for voltage source inverter fed induction motor drives. The direct torque control is one of the excellent strategies available for torque control of induction machine. It is considered as an alternative to field oriented control technique. The Direct Torque Control scheme is characterized by the absence of PI regulators, co-ordinate transformations, current regulators and pulse width modulated signal generators. Direct Torque Control allows a good torque control in steady state and transient operating conditions. The direct torque control technique based on space vector modulation and switching table has been developed and presented in this paper.

  15. Arthrography of the ankle sprains

    International Nuclear Information System (INIS)

    Ankle arthrography, by direct puncture of joint cavity, is considered to be a simple and accurate diagnostic method for a precise evaluation of ligamentous injury. Forty-seven cases of ankle arthrography were successively performed in the patients of acute ankle sprains. The purpose of this study is to demonstrate how ankle arthrography can delineate the pathologic anatomy in such cases. The results are as follows: 1. Thirty cases among forty seven revealed the findings of ligament tears. 2. For better diagnostic accuracy, the arthrography should be performed within 72 hrs. after injury. 3. The anterior talofibular ligament tears were the most common (twenty-nine cases) of all and seventeen of them revealed tears without association of any other ligament tears. 4. There were ten cases of calcaneofibular ligament tears and nine of them were associated with anterior talofibular ligament tears. 5. Three cases of anterior tibiofibular and one deltoid ligament tears were demonstrated

  16. Complications in Ankle Fracture Surgery

    OpenAIRE

    Ovaska, Mikko

    2014-01-01

    Mikko Ovaska. Complications in Ankle Fracture Surgery. Helsinki Bone and Joint Research Group, Department of Orthopaedic Surgery and Traumatology, Faculty of Medicine, University of Helsinki, Finland. Helsinki 2014. Ankle fractures are among the most frequently encountered surgically treated fractures. The operative treatment of this fracture may be associated with several complications. The most frequently encountered complications are related wound healing, and deep infection may have d...

  17. Total ankle arthroplasty in France

    OpenAIRE

    Besse, Jean-Luc; Colombier, Jean-Alain; ASENCIO, Joseph; Bonnin, Michel; Gaudot, Fabrice; JARDE, Olivier; Judet, Thierry; MAESTRO, Michel; LEMRIJSE, Thibaut; LEONARDI, Christian; TOULLEC, Eric

    2010-01-01

    Objectives: After more than 10 years' experience in France, the French Foot Surgery Association (Association francaise de chirurgie du pied [AFCP]) presents an update on mobile-bearing ankle prostheses, based on a multicenter study. Meta-analysis - Biomechanics - Assessment and indications: A preliminary comparative metaanalysis of the literature studies on ankle and prosthesis biomechanics, reviews validated indications and contra-indications, and details clinical and radiological outcomes a...

  18. Design and Comparison Direct Torque Control Techniques for Induction Motors

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Kazmierkowski, Marian P.; Zelechowski, Marcin;

    2005-01-01

    In this paper a comparison of two significant control methods of induction motor are presented. The first one is a classical Direct Torque and Flux Control (DTC) and is compared with a scheme, which uses Space Vector Modulator (DTC-SVM). A comparison in respect to dynamic and steady state...

  19. A Fluctuating Torque

    Science.gov (United States)

    Zamorano, Nelson; Gómez, Alfredo

    2013-04-01

    The existence of a fluctuating torque generates a wide variety of possible orbits. This situation contrasts with those examples where the torque vanishes and the angular momentum remains constant. Here we study a two dimensional example with a logarithmic effective potential V(x,y)= 12,,^2o,[ x^2 + (y/b)^2], with a small deviation from the axis symmetry given by the constant b with b propose it as a good pedagogical tool for reviewing the main concepts of newtonian dynamics.

  20. Predictive Direct Torque Control for Flux and Torque Ripple Reduction

    OpenAIRE

    Beerten, Jef; Verveckken, Jan; Driesen, Johan

    2010-01-01

    In this paper, a prediction scheme is presented to diminish both the torque and flux ripples in a direct torque control (DTC) induction motor drive. In a discrete implementation of the classical DTC scheme, the time delay associated with data processing results in additional torque and flux ripples. This part of the ripples can amount to a significant fraction of the overall ripple if the hysteresis bands are comparable to the maximum torque and flux variations in one sampling interval. This ...

  1. Determining a Method of Enabling and Disabling the Integral Torque in the SDO Science and Inertial Mode Controllers

    Science.gov (United States)

    Vess, Melissa F.; Starin, Scott R.

    2007-01-01

    During design of the SDO Science and Inertial mode PID controllers, the decision was made to disable the integral torque whenever system stability was in question. Three different schemes were developed to determine when to disable or enable the integral torque, and a trade study was performed to determine which scheme to implement. The trade study compared complexity of the control logic, risk of not reenabling the integral gain in time to reject steady-state error, and the amount of integral torque space used. The first scheme calculated a simplified Routh criterion to determine when to disable the integral torque. The second scheme calculates the PD part of the torque and looked to see if that torque would cause actuator saturation. If so, only the PD torque is used. If not, the integral torque is added. Finally, the third scheme compares the attitude and rate errors to limits and disables the integral torque if either of the errors is greater than the limit. Based on the trade study results, the third scheme was selected. Once it was decided when to disable the integral torque, analysis was performed to determine how to disable the integral torque and whether or not to reset the integrator once the integral torque was reenabled. Three ways to disable the integral torque were investigated: zero the input into the integrator, which causes the integral part of the PID control torque to be held constant; zero the integral torque directly but allow the integrator to continue integrating; or zero the integral torque directly and reset the integrator on integral torque reactivation. The analysis looked at complexity of the control logic, slew time plus settling time between each calibration maneuver step, and ability to reject steady-state error. Based on the results of the analysis, the decision was made to zero the input into the integrator without resetting it. Throughout the analysis, a high fidelity simulation was used to test the various implementation methods.

  2. Torque-Wrench Extension Arm

    Science.gov (United States)

    Pacala, T. J.; Trujillo, D. D.; Laudenslager, J. B.

    1984-01-01

    Torque-wrench extension arm makes possible to apply torque to bolt, screw, or nut inaccessible to conventional wrenches or in areas where wrench cannot be manipulated. Used in narrow pockets and behind panels and walls.

  3. Contractile and elastic ankle joint muscular properties in young and older adults.

    Directory of Open Access Journals (Sweden)

    Christopher J Hasson

    Full Text Available The purpose of this study was to investigate age-related differences in contractile and elastic properties of both dorsi- (DF and plantarflexor (PF muscles controlling the ankle joint in young and older adults. Experimental data were collected while twelve young and twelve older male and female participants performed maximal effort isometric and isovelocity contractions on a dynamometer. Equations were fit to the data to give torque-angle (Tθ and torque-angular velocity (Tω relations. Muscle series-elasticity was measured during ramped dynamometer contractions using ultrasonography to measure aponeurosis extension as a function of torque; second order polynomials were used to characterize the torque-extension (TΔL relation. The results showed no age differences in DF maximal torque and none for female PF; however, older males had smaller maximal PF torques compared to young males. In both muscle groups and genders, older adults had decreased concentric force capabilities. Both DF and PF TΔL relations were more nonlinear in the older adults. Older PF, but not DF muscles, were stiffer compared to young. A simple antagonism model suggested age-related differences in Tθ and Tω relations would be magnified if antagonistic torque contributions were included. This assessment of static, dynamic, and elastic joint properties affords a comprehensive view of age-related modifications in muscle function. Although many clinical studies use maximal isometric strength as a marker of functional ability, the results demonstrate that there are also significant age-related modifications in ankle muscle dynamic and elastic properties.

  4. Spin-torque transistor

    NARCIS (Netherlands)

    Bauer, G.E.W.; Brataas, A.; Tserkovnyak, Y.; Van Wees, B.J.

    2003-01-01

    A magnetoelectronic thin-film transistor is proposed that can display negative differential resistance and gain. The working principle is the modulation of the soure–drain current in a spin valve by the magnetization of a third electrode, which is rotated by the spin-torque created by a control spin

  5. Spin torque transistor revisited

    NARCIS (Netherlands)

    Chiba, T.; Bauer, G.E.W.; Takahashi, S.

    2013-01-01

    We theoretically study the operation of a 4-terminal device consisting of two lateral thin-film spin valves that are coupled by a magnetic insulator such as yttrium iron garnet via the spin transfer torque. By magnetoelectronic circuit theory we calculate the current voltage characteristics and find

  6. Model predictive torque control with an extended prediction horizon for electrical drive systems

    Science.gov (United States)

    Wang, Fengxiang; Zhang, Zhenbin; Kennel, Ralph; Rodríguez, José

    2015-07-01

    This paper presents a model predictive torque control method for electrical drive systems. A two-step prediction horizon is achieved by considering the reduction of the torque ripples. The electromagnetic torque and the stator flux error between predicted values and the references, and an over-current protection are considered in the cost function design. The best voltage vector is selected by minimising the value of the cost function, which aims to achieve a low torque ripple in two intervals. The study is carried out experimentally. The results show that the proposed method achieves good performance in both steady and transient states.

  7. Simulation of human gait using computed torque control.

    Science.gov (United States)

    Unver, N F; Tümer, S T; Ozgören, M K

    2000-01-01

    This paper presents a method for the mathematical modeling of both the single and double support phases of the human gait. The governing equations are obtained by considering the linkage model to be in a floating state and the foot-ground interaction is imposed in the form of geometric constraints. Two stages for the single support phase and one stage for the double support phase are considered, each described by a different foot-ground constraint. Feedback controller functioning according to the computed torque control method is used to achieve the normal gait described by the hip and ankle trajectories. Weighted least square optimization is used to solve the redundancy of control torques during the double support phase. The geometric simulation indicates that the imposed trajectories can be realized by the proposed model with some deviations in joint motions. The control strategy is tested by artificially perturbing the trajectories. The corrective actions are able to resume the desired pattern within half cycle, but with control torque magnitudes considerably away from reasonable limits. This is attributed to the insufficiency of the planar kinematic model and the assumption that the joint torques are unbounded. PMID:10942991

  8. Ankle Brachial Index

    Energy Technology Data Exchange (ETDEWEB)

    Wikstroem, J.; Hansen, T.; Johansson, L.; Lind, L.; Ahlstroem, H. (Dept. of Radiology and Dept. of Medical Sciences, Uppsala Univ. Hospital, Uppsala (SE))

    2008-03-15

    Background: Whole-body magnetic resonance angiography (WBMRA) permits noninvasive vascular assessment, which can be utilized in epidemiological studies. Purpose: To assess the relation between a low ankle brachial index (ABI) and high-grade stenoses in the pelvic and leg arteries in the elderly. Material and Methods: WBMRA was performed in a population sample of 306 subjects aged 70 years. The arteries below the aortic bifurcation were graded after the most severe stenosis according to one of three grades: 0-49% stenosis, 50-99% stenosis, or occlusion. ABI was calculated for each side. Results: There were assessable WBMRA and ABI examinations in 268 (right side), 265 (left side), and 258 cases (both sides). At least one >=50% stenosis was found in 19% (right side), 23% (left side), and 28% (on at least one side) of the cases. The corresponding prevalences for ABI <0.9 were 4.5%, 4.2%, and 6.6%. An ABI cut-off value of 0.9 resulted in a sensitivity, specificity, and positive and negative predictive value of 20%, 99%, 83%, and 84% on the right side, and 15%, 99%, 82%, and 80% on the left side, respectively, for the presence of a >= 50% stenosis in the pelvic or leg arteries. Conclusion: An ABI <0.9 underestimates the prevalence of peripheral arterial occlusive disease in the general elderly population

  9. The origin of the ankle

    CERN Document Server

    Codino, A; Codino, Antonio; Plouin, Francois

    2007-01-01

    The differential intensity of cosmic radiation shows a sequence of depressions referred to as "knees" in a large energy band above 10^15 eV. The global depression entailed in the complete spectrum with respect to the extrapolated intensity based on low energy data amounts to a maximum factor of 8, occurring at 5 x 10^18 eV, where flux measurements exhibit a relative minimum, referred to as the "ankle". It is demonstrated by a full simulation of cosmic ray trajectories in the Galaxy that the intensity minimum around the ankle energy is primarily due to the nuclear interactions of the cosmic ions with the interstellar matter and to the galactic magnetic field. "Ankles" signal the onset energies of the rectilinear propagation in the Milky Way at the Earth, being for example, 4 x 10^18 eV for helium and 6 x 10^19 eV for iron. The ankle, in spite of its notable importance at the Earth, is a local perturbation of the universal spectrum which, between the knee and the ankle, decreases by a round factor 10^9, regaini...

  10. Posterior Ankle Structure Injury During Total Ankle Replacement.

    Science.gov (United States)

    Reb, Christopher W; McAlister, Jeffrey E; Hyer, Christopher F; Berlet, Gregory C

    2016-01-01

    Total ankle replacement studies have focused on reporting complications that are directly observed clinically or radiographically, including wound problems, technical errors, implant loosening, subsidence, infection, bone fractures, and heterotopic ossification. However, patients can still experience unresolved pain even when these problems have been ruled out. We initiated a study to more clearly define the relative risk of injury to the anatomic structures in the posterior ankle during total ankle replacement using a third-generation implant system. Ten fresh-frozen adult cadaveric below-the-knee specimens were positioned in the intraoperative positioning frame of an approved total ankle replacement system and adjusted to achieve proper foot alignment using fluoroscopic imaging. The relationship between the tibial cutting guide pins and the posterior neurovascular and tendon structures was measured using digital calipers. High rates of posterior structural injury were found. Nearly all proximal-medial pins encountered a posteromedial neurovascular structure, most commonly the tibial nerve. The distal-medial pins mainly encountered posteromedial tendinous structures, in particular, the flexor digitorum longus tendon. The proximal lateral pins were highly likely to encounter the Achilles tendon and the sural nerve. Our results support our hypothesis that the tibial neurovascular structures are at the greatest risk when preparing for and completing the bony resection, particularly with the medial and proximal cuts. Posterior ankle soft tissue structure injuries can occur during implantation but currently with unknown frequency and undetermined significance. Further study of posterior structural injuries could result in a more informed approach to post-total ankle replacement complications and management. PMID:27291681

  11. American Orthopaedic Foot and Ankle Society

    Science.gov (United States)

    ... education site of the American Orthopaedic Foot & Ankle Society. Patients Visit the official patient education site of the American Orthopaedic Foot & Ankle Society. Patients Visit the official patient education site of ...

  12. Long term outcomes of inversion ankle injuries

    OpenAIRE

    Anandacoomarasamy, A; Barnsley, L; Grujic, L

    2005-01-01

    Background: Ankle sprains are common sporting injuries generally believed to be benign and self limiting. However, some studies report a significant proportion of patients with ankle sprains having persistent symptoms for months or even years.

  13. Effects of ankle eversion taping using kinesiology tape in a patient with ankle inversion sprain

    OpenAIRE

    Lee, Sun-Min; Lee, Jung-Hoon

    2016-01-01

    [Purpose] The aim of this study was to report the effects of ankle eversion taping using kinesiology tape on ankle inversion sprain. [Subject] The subject was a 21-year-old woman with Grade 2 ankle inversion sprain. [Methods] Ankle eversion taping was applied to the sprained left ankle using kinesiology tape for 4 weeks (average, 15 h/day). [Results] Ankle instability and pain were reduced, and functional dynamic balance was improved after ankle eversion taping for 4 weeks. The Cumberland Ank...

  14. Direct Torque Control of Induction Motor with Matrix Converter

    Directory of Open Access Journals (Sweden)

    Khalaf Salloum Gaeid

    2016-05-01

    Full Text Available The matrix converter (MC with direct torque control (DTC combination is efficient way to get better performance specifications in the industry. The MC and the DTC advantages are combined together. The reduction of complexity and cost of DC link in the DTC since it has no capacitors in the circuit. However, the controlling torque is a big problem it in DTC because of high ripple torque production which results in vibrations response in the operation of the iductuction motor as it has no PID to control the torque directly. To overcome this, a combination of MC with DTC is applied to reduce the fluctuation in the output torque and minimize the steady state error. This paper presents the simulation analysis of induction machine drives using Maltlab/Simulink toolbox R2012a. Design of DTC induction motor drive, MC with constant switching frequency, speed controller and stability investigation as well as controllability and observabilty with minimum final prediction (FPE steady state error and loss functionality has been carried out precisely.

  15. Effects of ankle eversion taping using kinesiology tape in a patient with ankle inversion sprain.

    Science.gov (United States)

    Lee, Sun-Min; Lee, Jung-Hoon

    2016-01-01

    [Purpose] The aim of this study was to report the effects of ankle eversion taping using kinesiology tape on ankle inversion sprain. [Subject] The subject was a 21-year-old woman with Grade 2 ankle inversion sprain. [Methods] Ankle eversion taping was applied to the sprained left ankle using kinesiology tape for 4 weeks (average, 15 h/day). [Results] Ankle instability and pain were reduced, and functional dynamic balance was improved after ankle eversion taping for 4 weeks. The Cumberland Ankle Instability Tool score and reach distances in the Y-Balance and lunge tests were increased. [Conclusion] Repeated ankle eversion taping may be an effective treatment intervention for ankle inversion sprain. PMID:27064668

  16. Rehabilitation of Syndesmotic (High) Ankle Sprains

    OpenAIRE

    Williams, Glenn N; Allen, Eric J.

    2010-01-01

    Context: High ankle sprains are common in athletes who play contact sports. Most high ankle sprains are treated nonsurgically with a rehabilitation program. Evidence Acquisition: All years of PUBMED, Cochrane Database of Systematic Reviews, CINAHL PLUS, SPORTDiscuss, Google Scholar, and Web of Science were searched to August 2010, cross-referencing existing publications. Keywords included syndesmosis ankle sprain or high ankle sprain and the following terms: rehabilitation, treatment, cryothe...

  17. Osteoligamentous injuries of the medial ankle joint

    OpenAIRE

    Lötscher, P.; Lang, T. H.; Zwicky, L.; Hintermann, B; Knupp, M

    2015-01-01

    Injuries of the ankle joint have a high incidence in daily life and sports, thus, playing an important socioeconomic role. Therefore, proper diagnosis and adequate treatment are mandatory. While most of the ligament injuries around the ankle joint are treated conservatively, great controversy exists on how to treat deltoid ligament injuries in ankle fractures. Missed injuries and inadequate treatment of the medial ankle lead to inferior outcome with instability, progressive deformity, and ank...

  18. The Incidence of Ankle Sprains in Orienteering.

    Science.gov (United States)

    Ekstrand, Jan; And Others

    1990-01-01

    Investigates relationship between ankle sprains and participation time in competitive orienteering. Examined 15,474 competitors in races in the Swedish O-ringen 5-day event in 1987. Injuries requiring medical attention were analyzed, showing 137 (23.9 percent) ankle sprains. Injury incidence was 8.4/10,000 hours. Incidence of ankle sprains was…

  19. Acute Ankle Sprains in Primary Care

    NARCIS (Netherlands)

    R.M. van Rijn (Rogier)

    2010-01-01

    textabstractOf all injuries of the musculoskeletal system, 25% are acute lateral ankle sprains.1 In the USA and the UK there are about 23,000 and 5000 ankle sprains, respectively, each day. In the Netherlands approximately 600,000 people sustain an ankle injury each year, of those 120,000 occur duri

  20. Sports Injuries to the Foot and Ankle

    Science.gov (United States)

    ... the Foot and Ankle Text Size Print Bookmark Sports Injuries to the Foot and Ankle Depending on the sport, your feet and ankles can certainly take a ... the injury risk factors while playing your favorite sport, see the topics listed below or read the ...

  1. Walking cycle control for an active ankle prosthesis with one degree of freedom monitored from a personal computer.

    Science.gov (United States)

    Cordero Andrés, Guzhñay; Arévalo Luis, Calle; Abad Julio, Zambrano

    2015-08-01

    This paper proposes a fuzzy control algorithm for human walking cycle of an active ankle prosthesis for people who have suffered amputation of the lower limb, the system has one degree of freedom in the sagittal plane. Also, a biomechanical analysis of foot and ankle is shown to define the phases of plantar support and swinging. The used actuator is an intelligent servomotor, Dynamixel MX-106T which has torque, current and position feedback, among others, allowing real-time telemetry of the prototype implemented in a microcontroller system. PMID:26737084

  2. Expecting ankle tilts and wearing an ankle brace influence joint control in an imitated ankle sprain mechanism during walking.

    Science.gov (United States)

    Gehring, Dominic; Wissler, Sabrina; Lohrer, Heinz; Nauck, Tanja; Gollhofer, Albert

    2014-03-01

    A thorough understanding of the functional aspects of ankle joint control is essential to developing effective injury prevention. It is of special interest to understand how neuromuscular control mechanisms and mechanical constraints stabilize the ankle joint. Therefore, the aim of the present study was to determine how expecting ankle tilts and the application of an ankle brace influence ankle joint control when imitating the ankle sprain mechanism during walking. Ankle kinematics and muscle activity were assessed in 17 healthy men. During gait rapid perturbations were applied using a trapdoor (tilting with 24° inversion and 15° plantarflexion). The subjects either knew that a perturbation would definitely occur (expected tilts) or there was only the possibility that a perturbation would occur (potential tilts). Both conditions were conducted with and without a semi-rigid ankle brace. Expecting perturbations led to an increased ankle eversion at foot contact, which was mediated by an altered muscle preactivation pattern. Moreover, the maximal inversion angle (-7%) and velocity (-4%), as well as the reactive muscle response were significantly reduced when the perturbation was expected. While wearing an ankle brace did not influence muscle preactivation nor the ankle kinematics before ground contact, it significantly reduced the maximal ankle inversion angle (-14%) and velocity (-11%) as well as reactive neuromuscular responses. The present findings reveal that expecting ankle inversion modifies neuromuscular joint control prior to landing. Although such motor control strategies are weaker in their magnitude compared with braces, they seem to assist ankle joint stabilization in a close-to-injury situation. PMID:24365326

  3. PILL series. Doctor, I sprained my ankle

    OpenAIRE

    How, Choon How; Tan, Ken Jin

    2014-01-01

    Ankle sprains constitute the majority of ankle injuries, and result in pain, limited mobility/exercise and loss of school/work days. Ankle sprains involve at least one of the ankle ligaments and range from a micro tear to complete tear of the ligament or group of ligaments. The most common mechanism of ankle sprains is inversion stress of a plantar-flexed foot, while the most frequently injured ligament is the anterior talofibular ligament. The attending clinician needs to stratify the risk o...

  4. DEVELOPMENT OF DIRECT TORQUE CONTROL MODELWITH USING SVI FOR THREE PHASE INDUCTION MOTOR

    Directory of Open Access Journals (Sweden)

    MUKESH KUMAR ARYA

    2011-08-01

    Full Text Available Direct torque control method is one of the best control strategies which allow a torque control in steady state and transient operation of induction motor. The main aim of direct torque control strategies is to effectively control the torque and flux of induction motor. Direct torque control method made the motor more accurate and fasttorque control, high dynamic speed response and simple to control. This paper present the principle of the direct torque control for voltage source inverter fed induction motor drive, and switching table, amplitude selection of the hysterics band of torque and flux. and also this method based on space vector modulation And its considered as an alternative to field oriented control technique. direct torque control methods is the first technology to control the ‘real’ motor control variable of torque and flux. and its has also more advantage such as it not required a feedback device and also not need external excitation. The performance of direct torque controlmethod has been demonstrated by simulation using a simulation package in matlab.

  5. MR Imaging of Ankle Impingement Syndromes

    Directory of Open Access Journals (Sweden)

    Seyed Hassan Mostafavi

    2010-05-01

    Full Text Available Ankle impingement syndromes are characterized by painful friction of joint tissues. This is both the cause and the effect of altered joint biomechanics. The leading causes of impingement lesions are posttraumatic ankle injuries, usually ankle sprains, resulting in chronic ankle pain. "nBased on anatomic and clinical viewpoints, there are five types of ankle impingement syndromes:"n1. Anterolateral"n2. Anterior"n3. Anteromedial"n4. Posteromedial"n5. Posterior"nCareful analyses of patient history and signs and symptoms at physical examination can suggest a specific diagnosis in most patients. MR imaging and MR arthrography are the most useful imaging methods for detecting the osseous and soft-tissue abnormalities present in these syndromes and for ruling out other potential causes of chronic ankle pain. "nThis presentation summarizes the MR imaging, and MR arthrography findings of ankle impingement syndromes.

  6. Ankle inversion taping using kinesiology tape for treating medial ankle sprain in an amateur soccer player.

    Science.gov (United States)

    Lee, Sun-Min; Lee, Jung-Hoon

    2015-07-01

    [Purpose] The purpose of this study was to report the effects of ankle inversion taping using kinesiology tape in a patient with a medial ankle sprain. [Subject] A 28-year-old amateur soccer player suffered a Grade 2 medial ankle sprain during a match. [Methods] Ankle inversion taping was applied to the sprained ankle every day for 2 months. [Results] His symptoms were reduced after ankle inversion taping application for 2 months. The self-reported function score, the reach distances in the Star Excursion Balance Test, and the weight-bearing ankle dorsiflexion were increased. [Conclusion] This study showed that ankle inversion taping using kinesiology tape may be an effective therapy for a patient with a medial ankle sprain. PMID:26311991

  7. Syndesmotic ankle sprains in athletes.

    Science.gov (United States)

    Williams, Glenn N; Jones, Morgan H; Amendola, Annunziato

    2007-07-01

    Ankle sprains are among the most common athletic injuries and represent a significant source of persistent pain and disability. Despite the high incidence of ankle sprains in athletes, syndesmosis injuries have historically been underdiagnosed, and assessment in terms of severity and optimal treatment has not been determined. More recently, a heightened awareness in sports medicine has resulted in more frequent diagnoses of syndesmosis injuries. However, there is a low level of evidence and a paucity of literature on this topic compared with lateral ankle sprains. As a result, no clear guidelines are available to help the clinician assess the severity of injury, choose an imaging modality to visualize the injury, make a decision in terms of operative versus nonoperative treatment, or decide when the athlete may return to play. Increased knowledge and understanding of these injuries by clinicians and researchers are essential to improve the prevention, diagnosis, and treatment of this significant condition. This review will discuss the anatomy, mechanism of injury, diagnosis, and treatment of syndesmosis sprains of the ankle while identifying controversies in management and topics for future research. PMID:17519439

  8. Experimental evaluation of a portable powered ankle-foot orthosis.

    Science.gov (United States)

    Shorter, Kenneth A; Li, Yifan; Morris, Emily A; Kogler, Géza F; Hsiao-Wecksler, Elizabeth T

    2011-01-01

    Ankle-foot orthoses (AFOs) ameliorate the impact of impairments to the lower limb neuromuscular motor system that affect gait. Emerging technologies provide a vision for fully powered, untethered AFOs. The portable powered AFO (PPAFO) provides both plantarflexor and dorsiflexor torque assistance via a bi-directional pneumatic rotary actuator. The system uses a portable pneumatic power source (bottle of compressed CO(2)) and embedded electronics to control foot motion during level walking. Experimental data were collected to demonstrate functionality from two subjects with bilateral impairments to the lower legs. These data demonstrated the PPAFO's ability to provide functional assistance during gait. The stringent design requirements of light weight, small size, high efficiency and low noise make the creation of daily wear assist devices challenging; but once such devices appear, they will present new opportunities for clinical treatment of gait abnormalities. PMID:22254386

  9. Ankle inversion taping using kinesiology tape for treating medial ankle sprain in an amateur soccer player

    OpenAIRE

    Lee, Sun-Min; Lee, Jung-Hoon

    2015-01-01

    [Purpose] The purpose of this study was to report the effects of ankle inversion taping using kinesiology tape in a patient with a medial ankle sprain. [Subject] A 28-year-old amateur soccer player suffered a Grade 2 medial ankle sprain during a match. [Methods] Ankle inversion taping was applied to the sprained ankle every day for 2 months. [Results] His symptoms were reduced after ankle inversion taping application for 2 months. The self-reported function score, the reach distances in the S...

  10. A skyrmion-based spin-torque nano-oscillator

    Science.gov (United States)

    Garcia-Sanchez, F.; Sampaio, J.; Reyren, N.; Cros, V.; Kim, J.-V.

    2016-07-01

    A model for a spin-torque nano-oscillator based on the self-sustained oscillation of a magnetic skyrmion is presented. The system involves a circular nanopillar geometry comprising an ultrathin film free magnetic layer with a strong Dzyaloshinkii–Moriya interaction and a polariser layer with a vortex-like spin configuration. It is shown that spin-transfer torques due to current flow perpendicular to the film plane leads to skyrmion gyration that arises from a competition between geometric confinement due to boundary edges and the vortex-like polarisation of the spin torques. A phenomenology for such oscillations is developed and quantitative analysis using micromagnetics simulations is presented. It is also shown that weak disorder due to random anisotropy variations does not influence the main characteristics of the steady-state gyration.

  11. Anatomy of the ankle ligaments: a pictorial essay

    NARCIS (Netherlands)

    P. Golanó; J. Vega; P.A.J. de Leeuw; F. Malagelada; M.C. Manzanares; V. Götzens; C.N. van Dijk

    2010-01-01

    Understanding the anatomy of the ankle ligaments is important for correct diagnosis and treatment. Ankle ligament injury is the most frequent cause of acute ankle pain. Chronic ankle pain often finds its cause in laxity of one of the ankle ligaments. In this pictorial essay, the ligaments around the

  12. SYNDESMOTIC ANKLE INJURY REHABILITATION EXERCISE PACKAGE FOR ICE HOCKEY PLAYERS

    OpenAIRE

    Kuznetsov, Vitali

    2013-01-01

    SYNDESMOTIC ANKLE INJURY REHABILITATION EXERCISE PACKAGE FOR ICE HOCKEY PLAYERS Kuznetsov, Vitali Satakunnan ammattikorkeakoulu, Satakunta University of Applied Sciences Degree Programme in Physiotherapy November 2013 Supervisor: Bärlund, Esa Number of pages: 42 Appendices: 2 Keywords: ankle, ice hockey, ice hockey injuries, high ankle sprain, ankle sprain rehabilitation, ankle injury prevention __________________________________________________________________ ...

  13. A Comparison of Total and Intrinsic Muscle Stiffness Among Flexors and Extensors of the Ankle, Knee and Elbow

    Science.gov (United States)

    Lemoine, Sandra M.

    1997-01-01

    This study examined 3 methods that assessed muscle stiffness. Muscle stiffness has been quantified by tissue reactive force (transverse stiffness), vibration, and force (or torque) over displacement. Muscle stiffness also has two components: reflex (due to muscle sensor activity) and intrinsic (tonic firing of motor units, elastic nature of actin and myosin cross bridges, and connective tissue). This study compared three methods of measuring muscle stiffness of agonist-antagonist muscle pairs of the ankle, knee and elbow.

  14. Torque control for electric motors

    Science.gov (United States)

    Bernard, C. A.

    1980-01-01

    Method for adjusting electric-motor torque output to accomodate various loads utilizes phase-lock loop to control relay connected to starting circuit. As load is imposed, motor slows down, and phase lock is lost. Phase-lock signal triggers relay to power starting coil and generate additional torque. Once phase lock is recoverd, relay restores starting circuit to its normal operating mode.

  15. Direct Torque Control of Sensorless Induction Motor Drives: A Sliding-Mode Approach

    DEFF Research Database (Denmark)

    Lascu, Cristian; Boldea, Ion; Blaabjerg, Frede

    2004-01-01

    Direct torque control (DTC) is known to produce fast response and robust control in ac adjustable-speed drives. However, in the steady-state operation, notable torque, flux, and current pulsations occur. A new, direct torque and flux control strategy based on variable-structure control and space......-vector pulsewidth modulation is proposed for induction motor sensorless drives. The DTC transient merits and robustness are preserved and the steady-state behaviour is improved by reducing the torque and flux pulsations. A sliding-mode observer using a dual reference frame motor model is introduced and tested....... Simulations and comparative experimental results with the proposed control scheme, versus classic DTC, are presented. Very-low-speed sensorless operation (3 r/min) is demonstrated....

  16. Oscillation characteristics of zero-field spin transfer oscillators with field-like torque

    International Nuclear Information System (INIS)

    We theoretically investigate the influence of the field-like spin torque term on the oscillation characteristics of spin transfer oscillators, which are based on MgO magnetic tunnel junctions (MTJs) consisting of a perpendicular magnetized free layer and an in-plane magnetized pinned layer. It is demonstrated that the field-like torque has a strong impact on the steady-state precession current region and the oscillation frequency. In particular, the steady-state precession can occur at zero applied magnetic field when the ratio between the field-like torque and the spin transfer torque takes up a negative value. In addition, the dependence of the oscillation properties on the junction sizes has also been analyzed. The results indicate that this compact structure of spin transfer oscillator without the applied magnetic field is practicable under certain conditions, and it may be a promising configuration for the new generation of on-chip oscillators

  17. Effectiveness of an outside-the-boot ankle brace in reducing parachuting related ankle injuries

    OpenAIRE

    Schmidt, M.; Sulsky, S; Amoroso, P.

    2005-01-01

    Objectives: To examine the efficacy of an outside-the-boot parachute ankle brace (PAB) in reducing risk of ankle injury to army paratrooper trainees and to identify inadvertent risks associated with PAB use.

  18. Hydrocolonotherapy ankle joints after injuries

    Directory of Open Access Journals (Sweden)

    Volodymyr Muchin

    2016-02-01

    Full Text Available Purpose: to improve efficiency of gydrokinesitherapy by means of specially designed devices and monolasts for patients after ankle joint injuries. Material & Methods: there are pedagogical methods, clinical and radiological methods, anthropometric measurements and goniometry were used. Results: the author's technique of hydrokinesitherapy with application hydrokinesimechanotherapy device in the program of physical rehabilitation which provides optimum conditions for the recovery process was developed. Conclusions: the specially designed hydrokinesomechanotherapeutic device and monolasts are allow strictly controlled movement in all planes of the ankle joint, which contributes to the acceleration of the recovery; the conducted anthropometric and goniometric studies were indicate more rapid elimination of edema, increase movement amplitude, carries opposition to the development of contractures and muscle atrophy.

  19. Safety and efficiency of the Ottawa Ankle Rule in a Swiss population with ankle sprains

    OpenAIRE

    Can, U; Ruckert, R; Held, U; Buchmann, P; Platz, A; Bachmann, L M

    2008-01-01

    OBJECTIVES: We examined the accuracy of the Ottawa Ankle Rule (OAR) to rule out ankle and mid-foot fractures in patients presenting with acute ankle sprain and differences of accuracy between surgeons and non-surgeons. DESIGN: Prospective cohort study. SETTING: Swiss urban secondary care centre. PARTICIPANTS: Between September 2001 and October 2002 359 patients presented with a case of ankle sprain. Of these, 251 patients both met recruitment criteria and provided data for this study. A group...

  20. Ottawa Ankle Rules and Subjective Surgeon Perception to Evaluate Radiograph Necessity Following Foot and Ankle Sprain

    OpenAIRE

    Pires, RES; Pereira, AA; Abreu-e-Silva, GM; Labronici, PJ; Figueiredo, LB; Godoy-Santos, AL; Kfuri, M

    2014-01-01

    Background: Foot and ankle injuries are frequent in emergency departments. Although only a few patients with foot and ankle sprain present fractures and the fracture patterns are almost always simple, lack of fracture diagnosis can lead to poor functional outcomes. Aim: The present study aims to evaluate the reliability of the Ottawa ankle rules and the orthopedic surgeon subjective perception to assess foot and ankle fractures after sprains. Subjects and Methods: A cross-sectional study was ...

  1. Sonographic anatomy of the ankle

    OpenAIRE

    Precerutti, M.; Bonardi, M.; Ferrozzi, G.; Draghi, F.

    2013-01-01

    Ankle sonography is one of the most commonly ordered examinations in the field of osteoarticular imaging, and it requires intimate knowledge of the anatomic structures that make up the joint. For practical purposes, the examination can be divided into four compartments, which are analyzed in this pictorial essay: the anterior compartment, which includes the tibialis anterior, extensor hallucis longus, and extensor digitorum longus tendons; the accessory peroneus tertius tendon; and the extens...

  2. Hydrocolonotherapy ankle joints after injuries

    OpenAIRE

    Volodymyr Muchin; Oleksandr Zviriaka

    2016-01-01

    Muchin V., Zviriaka O. Purpose: to improve efficiency of gydrokinesitherapy by means of specially designed devices and monolasts for patients after ankle joint injuries. Material & Methods: there are pedagogical methods, clinical and radiological methods, anthropometric measurements and goniometry were used. Results: the author's technique of hydrokinesitherapy with application hydrokinesimechanotherapy device in the program of physical rehabilitation which provides optimum conditions for...

  3. Minimization of Torque Ripple in DTC of Induction Motor Using Fuzzy Mode Duty Cycle Controller

    OpenAIRE

    Turki Y. Abdalla; Haroution Antranik Hairik; Adel M. Dakhil

    2011-01-01

    Among all control methods for induction motor drives, Direct Torque Control (DTC) seems to be particularly interesting being independent of machine rotor parameters and requiring no speed or position sensors. The DTC scheme is characterized by the absence of PI regulators, coordinate transformations, current regulators and PWM signals generators. In spite of its simplicity, DTC allows a good torque control in steady state and transient operating conditions to be obt...

  4. Ankle reconstruction in type II fibular hemimelia

    OpenAIRE

    El-Tayeby, Hazem Mossad; Ahmed, Amin Abdel Razek Youssef

    2012-01-01

    Ankle reconstruction prior to limb lengthening for was performed in 13 patients with fibular hemimelia with complete radiological absence of the fibula (type II). There were different degrees of absence of metatarsal rays. The hindfoot deformity was a heel valgus in 12 patients and equinovarus in 1 patient. The patients’ ages ranged from 9 to 26 months. Excision of the fibular anlage was performed with lateral subtalar and ankle soft tissue releases to restore the ankle and subtalar joint rel...

  5. Predicting Functional Recovery after Acute Ankle Sprain

    OpenAIRE

    Sean R O'Connor; Bleakley, Chris M; Tully, Mark A; McDonough, Suzanne M

    2013-01-01

    INTRODUCTION:Ankle sprains are among the most common acute musculoskeletal conditions presenting to primary care. Their clinical course is variable but there are limited recommendations on prognostic factors. Our primary aim was to identify clinical predictors of short and medium term functional recovery after ankle sprain.METHODS:A secondary analysis of data from adult participants (N = 85) with an acute ankle sprain, enrolled in a randomized controlled trial was undertaken. The predictive v...

  6. How to Stretch Your Ankle After a Sprain

    Science.gov (United States)

    ... Ankle After A Sprain How to Stretch Your Ankle After A Sprain Page Content You should perform the following stretches ... Consider these home exercises when recuperating from an ankle sprain. Perform them twice per day. While seated, bring ...

  7. Hybrid synchronous motor electromagnetic torque research

    Directory of Open Access Journals (Sweden)

    Suvorkova Elena E.

    2014-01-01

    Full Text Available Electromagnetic field distribution models in reluctance and permanent magnet parts were made by means of Elcut. Dependences of electromagnetic torque on torque angle were obtained.

  8. Total Ankle Arthroplasty: An Imaging Overview

    Science.gov (United States)

    Kim, Da-Rae; Potter, Hollis G.; Li, Angela E.; Chun, Ka-Young; Jung, Yoon Young; Kim, Jin-Su; Young, Ki-Won

    2016-01-01

    With advances in implant technology, total ankle arthroplasty (TAA) has become an increasingly popular alternative to arthrodesis for the management of end-stage ankle arthritis. However, reports in the literature do not focus on the imaging features of TAA. Through a literature review, we demonstrate basic design features of the current ankle arthroplasty system, and the normal and abnormal postoperative imaging features associated with such devices. Pre- and postoperative evaluations of ankle arthroplasty mainly include radiography; in addition, computed tomography and magnetic resonance imaging provide further characterization of imaging abnormalities. Familiarization with multimodal imaging features of frequent procedural complications at various postoperative intervals is important in radiological practice. PMID:27134529

  9. Surgical treatment of the arthritic varus ankle.

    Science.gov (United States)

    Easley, Mark E

    2012-12-01

    Within the past several years, the arthritic varus ankle has been addressed extensively in Foot and Ankle Clinics, with numerous excellent reviews by particularly knowledgeable authors. To support these outstanding contributions, this article provides a practical approach to this challenging constellation of foot and ankle abnormalities. Varus ankle arthritis exists on a continuum that prompts the treating surgeon to be familiar with a spectrum of surgical solutions, including joint-sparing realignment, arthroplasty, and arthrodesis. Each of these treatment options is addressed with several expanded case examples and supports the management approaches with the available pertinent literature. PMID:23158376

  10. Evidence-based treatment for ankle injuries: a clinical perspective

    OpenAIRE

    Lin, Chung-Wei Christine; Hiller, Claire E; de Bie, Rob A.

    2010-01-01

    The most common ankle injuries are ankle sprain and ankle fracture. This review discusses treatments for ankle sprain (including the management of the acute sprain and chronic instability) and ankle fracture, using evidence from recent systematic reviews and randomized controlled trials. After ankle sprain, there is evidence for the use of functional support and non-steroidal anti-inflammatory drugs. There is weak evidence suggesting that the use of manual therapy may lead to positive short-t...

  11. Inverse Dynamics Model for the Ankle Joint with Applications in Tibia Malleolus Fracture

    Science.gov (United States)

    Budescu, E.; Merticaru, E.; Chirazi, M.

    The paper presents a biomechanical model of the ankle joint, in order to determine the force and the torque of reaction into the articulation, through inverse dynamic analysis, in various stages of the gait. Thus, knowing the acceleration of the foot and the reaction force between foot and ground during the gait, determined by experimental measurement, there was calculated, for five different positions of the foot, the joint reaction forces, on the basis of dynamic balance equations. The values numerically determined were compared with the admissible forces appearing in the technical systems of osteosynthesis of tibia malleolus fracture, in order to emphasize the motion restrictions during bone healing.

  12. Do ankle braces provide similar effects on ankle biomechanical variables in subjects with and without chronic ankle instability during landing?

    Institute of Scientific and Technical Information of China (English)

    Songning; Zhang; Michael; Wortley; Julia; Freedman; Silvernail; Daniel; Carson; Maxime; R.Paquette

    2012-01-01

    <正>Purpose:The purpose of this study was to examine effects of a sport version of a semi-rigid ankle brace(ElementTM) and a soft ankle brace (ASO) on ankle biomechanics and ground reaction forces(GRFs) during a drop landing activity in subjects with chronic ankle instability(CAD compared to healthy subjects with no history of CAI. Methods:Ten healthy subjects and 10 subjects who had multiple ankle sprains participated in the study as the control and unstable subjects, respectively.The CAI subjects were age,body mass index and gender matched with the control subjects.The arch index and ankle functions of the subjects were measured in a subject screening session.During the biomechanical test session,participants performed five trials of drop landing from 0.6 m,wearing no brace(NB).Element? brace and ASO brace.Simultaneous recording of three-dimensional kinematic(240 Hz) and GRF(1200 Hz) data were performed. Results:The CAI subjects had lower ankle functional survey scores.The arch index and deformity results showed greater arch deformity of ElementTM against a static load than in NB and ASO due to greater initial arch position held by the brace.CAI participants had greater eversion velocity than healthy controls.The ASO brace reduced the first peak vertical GRF whereas ElementTM increased 2nd peak vertical GRF. ElementTMbrace reduced eversion range of motion(ROM) and peak eversion velocity compared to NB and ASO.In addition,ElementTM reduced dorsiflexion ROM and increased peak plantarflexion moment compared to NB and ASO. Conclusion:Results of static arch measurements and dynamic ankle motion suggest that the restrictions offered by both braces are in part due to more dorsiflexed ankle positions at contact,and higher initial arch position and stiffer ankle for ElementTM.

  13. A study on correlation of proprioception and strength between left and right ankles of elder people%老年人两侧踝关节本体感觉及其与肌力的相关性研究

    Institute of Scientific and Technical Information of China (English)

    王雪强; 俞卓伟; 刘静; 郑洁皎; 曾德铭; 陈千红

    2011-01-01

    Objective: To compare the difference of proprioception and peak torque between left and right ankles of elder people,and analyse its' correlation.Method:Proprioception ankle joints of fifty-three healthy elder people(23 male and 30 female; average age 66.2 ± 5.1 year) were measured for two tests on Biodex system 3 dynamometer. The absolute error ankle in passive replication test was used to assess ankle proprioceptive function. The ankle flexor muscle, extensor muscle isokinetic concentric peak torque were measured on Biodex system 3 dynamometer at the speed of 30°/s. The main measurement indexes were concentric peak torque and relative peak torque of ankle flexor muscle and extensor muscles. Result:The absolute error angles of passive replication test on left ankels were less than that on right ankles(P= 0.011). Concentric peak torques of flexor muscle and extensor muscle of left ankles were less ankles than that of right ankle(P0.05). Conclusion: Proprioception of left ankle is better than that of right ankle, but concentric peak torque and relative peak torque of flexor muscle and extensor muscle of left ankle is less than that of right ankle. There was no significant correlation between the proprioception and muscle strength in the elderly.%目的:对比老年人左右两侧踝关节本体感觉的差异和左右两侧峰力矩之间的差异,分析踝关节本体感觉与其肌力的相关性。方法:在Biodex System 3等速系统上用被动复位测试法测试53名正常老年人(其中男23名、女30名;平均年龄66.2±5.1岁)的踝关节本体感觉,本研究以被动复位绝对误差角度作为个体本体感觉能力优劣的代表。同时采用Biodex Svstem 3等速系统对踝关节屈肌、伸肌肌群在30°/s的角速度下进行向心测试,主要观察指标为各肌群的峰力矩与相对峰力矩。结果:①左侧踝关节复位的绝对误差角度小于有侧踝关节(P=0.011);②左侧踝关节屈肌、伸肌的峰力

  14. Torque-Summing Brushless Motor

    Science.gov (United States)

    Vaidya, J. G.

    1986-01-01

    Torque channels function cooperatively but electrically independent for reliability. Brushless, electronically-commutated dc motor sums electromagnetic torques on four channels and applies them to single shaft. Motor operates with any combination of channels and continues if one or more of channels fail electrically. Motor employs single stator and rotor and mechanically simple; however, each of channels electrically isolated from other so that failure of one does not adversely affect others.

  15. Redefining prosthetic ankle mechanics: non-anthropomorphic ankle design.

    Science.gov (United States)

    LaPrè, Andrew K; Sup, Frank

    2013-06-01

    The moment transferred at the residual limb socket interface of transtibial amputees can be a limiting factor of the comfort and activity level of lower limb amputees. The high pressures seen can be a significant source of pain, as well as result in deep tissue damage. The compensation of the sound limbs causes an asymmetrical gait which can be a contributor of early onset osteoarthritis in the sound limbs. It has been shown that the moment transferred with conventional passive prostheses can be lowered in magnitude by aligning the tibia with ground reaction forces, but this limits the effectiveness of the device. With recent powered prosthetics designed to mimic the missing limb, power can be injected into the gait cycle, but can also be limited by this pressure threshold. This paper shows the results of calculations that suggest that altering the prosthetic ankle mechanism can reduce the socket interface moments by as much as 50%. This supports the development of an active non-anthropomorphic ankle prosthesis which reduces socket interface moments while still injecting substantial power levels into the gait cycle. PMID:24187257

  16. Chinese Massage Therapy for Ankle Injury

    Institute of Scientific and Technical Information of China (English)

    CHEN Ming-xia; LI Nian-qun; HUANG Guo-qi

    2003-01-01

    Purpose: To explore the therapeutic methods and effects in the treatment of acute and chronic injuries of the ankle joint by Chinese massage therapy in combination with external application of Chinese herbal drugs and functional exercises. Methods: Totally, 36 cases of the patients with acute soft tissue injury, chronic soft tissue injury and post-fracture sequelae of the ankle joint were treated by Chinese massage therapy, external application or external wash of Chinese herbal drugs, and exercises of dorsal flexion and extension of the ankle joint, to observe the restoration of the ankle functions.Results: In 36 cases of the patients, the results showed remarkable effect in 18 cases, effect in 16 cases, failure in 2 cases and the effective rate in 94.4%. Conclusion: The combined use of Chinese massage therapy, external application of Chinese herbal drugs and functional exercises can produce precise effect in the treatment of soft tissue injury of the ankle joint.

  17. The role of ankle bracing for prevention of ankle sprain injuries.

    Science.gov (United States)

    Gross, Michael T; Liu, Hsin-Yi

    2003-10-01

    Lateral ankle sprains are one of the most common injuries incurred in recreational and competitive athletics. These injuries have a significant impact in terms of cost, athletic participation, and activities of daily living. Prophylactic ankle braces are often used to reduce the risk of injury recurrence when individuals return to athletic participation. The purpose of this clinical commentary is to review the literature and provide our own experience relative to the use of prophylactic ankle bracing. Relatively high incidence rates of ankle sprain injury have been reported for basketball and soccer athletes, military trainees, and individuals with a previous history of ankle sprain injury. Semirigid and laced ankle braces have significantly reduced the incidence of initial and recurrent ankle sprain injuries in athletic and military samples. With few exceptions, these braces do not appear to affect functional performance adversely. The prophylactic use of semirigid ankle braces appears warranted to reduce the incidence of initial and, in particular, recurrent ankle sprain injuries for individuals who participate in activities that have the highest risk for these injuries. Additional research is needed to evaluate the many new braces that are available and in use and their influence on the incidence of ankle sprain injury and functional performance. PMID:14620786

  18. EFFECTS OF FATIGUE & GENDER ON PERONEAL REFLEXES AFTER ANKLE INVERSION

    OpenAIRE

    Wilson, Erin Lawall

    2005-01-01

    An estimated 23,000 ankle injuries occur every day in the U.S. Ankle sprains account for 85% of all ankle injuries and inversion ankle sprains account for 85% of all ankle sprains. There is growing evidence that suggests gender and fatigue may increase the risk for inversion ankle sprains. Investigating the effects of fatigue and gender on peroneal reflex response after ankle inversion may help explain the differences in sprain rates with fatigue and gender. Therefore, the purpose of this stu...

  19. Integral torque balance in tokamaks

    International Nuclear Information System (INIS)

    The study is aimed at clarifying the balance between the sinks and sources in the problem of intrinsic plasma rotation in tokamaks reviewed recently by deGrassie (2009 Plasma Phys. Control. Fusion 51 124047). The integral torque on the toroidal plasma is calculated analytically using the most general magnetohydrodynamic (MHD) plasma model taking account of plasma anisotropy and viscosity. The contributions due to several mechanisms are separated and compared. It is shown that some of them, though, possibly, important in establishing the rotation velocity profile in the plasma, may give small input into the integral torque, but an important contribution can come from the magnetic field breaking the axial symmetry of the configuration. In tokamaks, this can be the error field, the toroidal field ripple or the magnetic perturbation created by the correction coils in the dedicated experiments. The estimates for the error-field-induced electromagnetic torque show that the amplitude of this torque is comparable to the typical values of torques introduced into the plasma by neutral beam injection. The obtained relations allow us to quantify the effect that can be produced by the existing correction coils in tokamaks on the plasma rotation, which can be used in experiments to study the origin and physics of intrinsic rotation in tokamaks. Several problems are proposed for theoretical studies and experimental tests.

  20. Conversion of ankle autofusion to total ankle replacement using the Salto XT revision prosthesis.

    Science.gov (United States)

    Williamson, Emilie R C; Demetracopoulos, Constantine A; Ellis, Scott J

    2016-09-01

    Few reports in the literature have described the conversion of a surgically fused ankle to a total ankle replacement. The takedown of an autofusion and conversion to a prosthesis has not been described. We report the case of a patient with severe rheumatoid arthritis with an ankle autofusion fixed in equinus and severe talonavicular arthritis that was converted to ankle replacement using the Salto XT revision system. We describe the reasons why the decision was made to perform total ankle arthroplasty while concomitantly fusing the talonavicular joint, and discuss the rationale of the various surgical treatment options considered. We describe the clinical and radiographic outcomes achieved in this case. At 12 months post-operatively the patient reported significant reduction of pain, increased FAOS scores and had increased ankle range of motion. PMID:27502236

  1. The torque ripple minimization of switched reluctance motors by torque waveform control

    Energy Technology Data Exchange (ETDEWEB)

    Diril, O. [Arcelik AS, R and D Dept., Istanbul (Turkey); Tuncay, R.N. [Istanbul Technical University, Dept. of Electrical Engineering, Istanbul (Turkey)

    2000-08-01

    This study presents a straightforward method to minimize torque ripples of SR motors by controlling the torque waveforms. The instantaneous torque and current functions, which yield zero torque ripple for constant torque, are developed theoretically, and later realised experimentally by employing the waveshape forming control technique for the torque and current. New controllability criteria are proposed to represent the speed limits, up to which zero torque-ripple is possible. Later, these criteria are verified experimentally. It is believed that, these new design tools would contribute for designing a torque-ripple free high-speed SR motor. (orig.)

  2. Foot and Ankle Injuries in Runners.

    Science.gov (United States)

    Tenforde, Adam S; Yin, Amy; Hunt, Kenneth J

    2016-02-01

    Foot and ankle injuries account for nearly one-third of running injuries. Achilles tendinopathy, plantar fasciopathy, and ankle sprains are 3 of the most common types of injuries sustained during training. Other common injuries include other tendinopathies of the foot and ankle, bone stress injuries, nerve conditions including neuromas, and joint disease including osteoarthritis. This review provides an evidence-based framework for the evaluation and optimal management of these conditions to ensure safe return to running participation and reduce risk for future injury. PMID:26616180

  3. Effects of Nintendo Wii Fit Plus training on ankle strength with functional ankle instability

    OpenAIRE

    Kim, Ki-Jong; Jun, Hyun-Ju; Heo, Myoung

    2015-01-01

    [Purpose] The objective of this study was to examine the effects of a training program using the Nintendo Wii Fit Plus on the ankle muscle strengths of subjects with functional ankle instability. [Subjects and Methods] This study was conducted using subjects in their 20s who had functional ankle instability. They were randomized to a strengthening training group and a balance training group with 10 subjects in each, and they performed an exercise using Nintendo Wii Fit Plus for 20 minutes. In...

  4. Clinical Value of the Ottawa Ankle Rules for Diagnosis of Fractures in Acute Ankle Injuries

    OpenAIRE

    Xin Wang; Shi-min Chang; Guang-rong Yu; Zhi-tao Rao

    2013-01-01

    BACKGROUND: The Ottawa ankle rules (OAR) are clinical decision guidelines used to identify whether patients with ankle injuries need to undergo radiography. The OAR have been proven that their application reduces unnecessary radiography. They have nearly perfect sensitivity for identifying clinically significant ankle fractures. OBJECTIVES: The purpose of this study was to assess the applicability of the OAR in China, to examine their accuracy for the diagnosis of fractures in patients with a...

  5. Primary ankle arthrodesis for neglected open weber B ankle fracture dislocation.

    LENUS (Irish Health Repository)

    Thomason, Katherine

    2014-07-01

    Primary ankle arthrodesis used to treat a neglected open ankle fracture dislocation is a unique decision. A 63-year-old man presented to the emergency department with a 5-day-old open fracture dislocation of his right ankle. After thorough soft tissue debridement, primary arthrodesis of the tibiotalar joint was performed using initial Kirschner wire fixation and an external fixator. Definitive soft tissue coverage was later achieved using a latissimus dorsi free flap. The fusion was consolidated to salvage the limb from amputation. The use of primary arthrodesis to treat a compound ankle fracture dislocation has not been previously described.

  6. Reduction of torque ripple in DTC for induction motor using input-output feedback linearization

    Directory of Open Access Journals (Sweden)

    Belkacem Sebti

    2011-01-01

    Full Text Available Direct torque control (DTC is known to produce fast response and robust control in AC adjustable-speed drives. However, in the steady-state operation, notable torque, flux, and current pulsations occur. In this paper a nonlinear DTC of IM drives is presented based on a Space Vector PWM scheme combined with Input-Output Feedback Linearization (IOFL technique. The variation of stator and rotor resistance due to changes in temperature or frequency deteriorates the performance of DTC controller by introducing errors in the estimated flux linkage and the electromagnetic torque. As a result, this approach will not be suitable for high power drives such as those used in tractions, as they require good torque control performance at considerably lower frequency. Finally, extensive simulation results are presented to validate the proposed technique. The system is tested at different speeds and a very satisfactory performance has been achieved.

  7. Improving the performance of hysteresis direct torque control of IPMSM using active filter topology

    Indian Academy of Sciences (India)

    Kayhan Gulez; Ali Ahmed Adam; Halit Pastaci

    2006-06-01

    This paper describes an active filter topology to improve the performance of hysteresis direct torque control (HDTC) of interior permanent magnet synchronous motor (IPMSM). The filter topology consists of an active filter and two RLC filters, and is connected to the main power circuit through a 1:1 transformer. The active filter is characterized by detecting the harmonics in the motor phase voltages and injecting equivalent harmonic voltages to produce almost sinusoidal voltage waveform to the motor terminals. The active filter uses hysteresis voltage controller while the motor main circuit uses hysteresis direct torque control. The simulation results of this combined control structure show considerable torque ripple reduction in the steady state range and adequate dynamic torque performance as well as considerable harmonic voltage and EMI noise reduction.

  8. SYSTEM FOR TORQUE CONVERTER DESIGN AND ANALYSIS BASED ON CAD/CFD INTEGRATED PLATFORM

    Institute of Scientific and Technical Information of China (English)

    WU Guangqiang; YAN Peng

    2008-01-01

    A 3D torque converter design system is developed based on numerical investigation into flow field and CAD technology. The 3D steady-state flow field simulation is undertaken by using time averaged Reynolds equation and k-epsilon turbulence model, with mixing-plane boundary conditions at three section interfaces. The blades are designed according to the flow field characteristics by using a reverse design method in the system. The accurateness of numerical analysis and the validity of design system are verified by the fluid field experiment of desingn example of the torque converter. This kind of design and analysis system for torque converter based on integration of comput ationol fluid dynamics (CFD) and CAD is a powerful tool for torque converter manufacturing, but also a prettg important significance for research and development.

  9. Fuzzy Backstepping Torque Control Of Passive Torque Simulator With Algebraic Parameters Adaptation

    Science.gov (United States)

    Ullah, Nasim; Wang, Shaoping; Wang, Xingjian

    2015-07-01

    This work presents fuzzy backstepping control techniques applied to the load simulator for good tracking performance in presence of extra torque, and nonlinear friction effects. Assuming that the parameters of the system are uncertain and bounded, Algebraic parameters adaptation algorithm is used to adopt the unknown parameters. The effect of transient fuzzy estimation error on parameters adaptation algorithm is analyzed and the fuzzy estimation error is further compensated using saturation function based adaptive control law working in parallel with the actual system to improve the transient performance of closed loop system. The saturation function based adaptive control term is large in the transient time and settles to an optimal lower value in the steady state for which the closed loop system remains stable. The simulation results verify the validity of the proposed control method applied to the complex aerodynamics passive load simulator.

  10. Lichen simplex chronicus on the ankle (image)

    Science.gov (United States)

    Lichen simplex chronicus on the ankle: Lichen simplex chronicus is also known as neurodermatitis. A minor itch may encourage scratching which increases the irritation, leading to more scratching. This ultimately results ...

  11. A novel dynamic ankle-supinating device.

    Science.gov (United States)

    Gutierrez, Gregory M; Kaminski, Thomas

    2010-02-01

    Lateral ankle sprains (LAS) are among the most common joint injuries, and although most are resolved with conservative treatment, others develop chronic ankle instability (AI). Considerable attention has been directed toward understanding the underlying causes of this pathology; however, little is known concerning the neuromuscular mechanisms behind AI. A biomechanical analysis of the landing phase of a drop jump onto a device that simulates the mechanism of a LAS may give insight into the dynamic restraint mechanisms of the ankle by individuals with AI. Furthermore, work evaluating subjects who have a history of at least one lateral ankle sprain, yet did not develop AI, may help elucidate compensatory mechanisms following a LAS event. Identifying proper neuromuscular control strategies is crucial in reducing the incidence of AI. PMID:20147765

  12. Osteoarthritis of the Foot and Ankle

    Science.gov (United States)

    ... joint. Diagnosis In diagnosing osteoarthritis, the foot and ankle surgeon will examine the foot thoroughly, looking for swelling in the joint, limited mobility, and pain with movement. In some cases, deformity ...

  13. Postoperative MR study of the ankle

    International Nuclear Information System (INIS)

    20 patients with acute traumatic rupture of the anterior talofibular ligament and ligamental suture were studied postoperatively by MRI. MR results were correlated with stress X-ray studies. We found a normal anterior talofibular ligament in eight cases. However, stress X-ray images showed normal stability of the ankle joint in eighteen cases. In six patients the anterior talofibular ligament was thickened, in another six cases it could not be separated from scar tissue. Therefore MR imaging of ankle ligaments did not allow a diagnosis of their function. Nevertheless, sequelae of the ankle trauma such as osteochondrosis, exsudation into the ankle joint and tendovaginitis of the flexor muscles were sensitively visualised by MR. (orig.)

  14. What Is a Foot and Ankle Surgeon?

    Science.gov (United States)

    ... school, the foot and ankle surgeon enters a postgraduate residency in podiatric medicine and surgery approved by ... disorders and injuries that affect people of all ages. They are uniquely qualified to detect the early ...

  15. Gait mode recognition and control for a portable-powered ankle-foot orthosis.

    Science.gov (United States)

    David Li, Yifan; Hsiao-Wecksler, Elizabeth T

    2013-06-01

    Ankle foot orthoses (AFOs) are widely used as assistive/rehabilitation devices to correct the gait of people with lower leg neuromuscular dysfunction and muscle weakness. We have developed a portable powered ankle-foot orthosis (PPAFO), which uses a pneumatic bi-directional rotary actuator powered by compressed CO2 to provide untethered dorsiflexor and plantarflexor assistance at the ankle joint. Since portability is a key to the success of the PPAFO as an assist device, it is critical to recognize and control for gait modes (i.e. level walking, stair ascent/descent). While manual mode switching is implemented in most powered orthotic/prosthetic device control algorithms, we propose an automatic gait mode recognition scheme by tracking the 3D position of the PPAFO from an inertial measurement unit (IMU). The control scheme was designed to match the torque profile of physiological gait data during different gait modes. Experimental results indicate that, with an optimized threshold, the controller was able to identify the position, orientation and gait mode in real time, and properly control the actuation. It was also illustrated that during stair descent, a mode-specific actuation control scheme could better restore gait kinematic and kinetic patterns, compared to using the level ground controller. PMID:24187192

  16. Design of a Robotic Ankle Joint for a Microspine-Based Robot

    Science.gov (United States)

    Thatte, Nitish

    2011-01-01

    Successful robotic exploration of near-Earth asteroids necessitates a method of securely anchoring to the surface of these bodies without gravitational assistance. Microspine grip- per arrays that can grasp rock faces are a potential solution to this problem. A key component of a future microspine-based rover will be the ankle used to attach each microspine gripper to the robot. The ankle's purpose is twofold: 1) to allow the gripper to conform to the rock so a higher percentage of microspines attach to the surface, and 2) to neutralize torques that may dislodge the grippers from the wall. Parts were developed using computer aided design and manufactured using a variety of methods including selective laser sintering, CNC milling, and traditional manual machining techniques. Upon completion of the final prototype, the gripper and ankle system was tested to demonstrate robotic engagement and disengagement of the gripper and to determine load bearing ability. The immediate application of this project is to out t the Lemur IIb robot so it can climb and hang from rock walls.

  17. Modified direct torque control method for induction motor drives based on amplitude and angle control of stator flux

    Energy Technology Data Exchange (ETDEWEB)

    Kumsuwan, Yuttana; Premrudeepreechacharn, Suttichai [Department of Electrical Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200 (Thailand); Toliyat, Hamid A. [Department of Electrical and Computer Engineering, Texas A and M University, College Station, TX 77843-3128 (United States)

    2008-10-15

    This paper proposes design and implementation of a direct torque controlled induction motor drive system. The method is based on control of separation between amplitude and angle of reference stator flux for determining reference stator voltage vector in generating PWM output voltage for induction motors. The objective is to reduce electromagnetic torque ripple and stator flux droop which result in a decrease in current distortion in steady-state condition. In addition, the proposed technique provides simplicity of a control system. The direct torque control is based on the relationship between instantaneous slip angular frequency and rotor angular frequency in adjustment of the reference stator flux angle. The amplitude of the reference stator flux is always kept constant at rated value. The system has been implemented to verify its capability such as torque and stator flux responses, stator phase current distortion both during dynamic and steady state with load variation, and low speed operation. (author)

  18. Postoperative infection in the foot and ankle.

    LENUS (Irish Health Repository)

    Chan, Victoria O

    2012-07-01

    Our discussion highlights the commonly performed surgical procedures in the foot and ankle and reviews the various imaging modalities available for the detection of infection with graphic examples to better enable radiologists to approach the radiological evaluation of postoperative infection in the foot and ankle. Discrimination between infectious and noninfectious inflammation remains a diagnostic challenge usually needing a combination of clinical assessment, laboratory investigations, and imaging studies to increase diagnostic accuracy.

  19. Is balance impaired by recurrent sprained ankle?

    OpenAIRE

    Isakov, E; Mizrahi, J.

    1997-01-01

    OBJECTIVE: To evaluate uninjured and recurrent sprained ankles during single leg standing, both with and without visual input, and the contribution of related proprioceptive feedback in this event. METHODS: A force measuring system was used for monitoring reaction forces in the anteroposterior and mediolateral directions during single leg standing. Differences between selected variables obtained in the uninjured and sprained ankles were analysed using two way analysis of variance. RESULTS: Fo...

  20. An epidemiological survey on ankle sprain.

    OpenAIRE

    Yeung, M S; Chan, K. M.; So, C H; Yuan, W Y

    1994-01-01

    Ankle sprain is a common sports injury and is often regarded as trivial by athletes and coaches. This epidemiological study was conducted among three categories of Hong Kong Chinese athletes: national teams, competitive athletes and recreational athletes. This study shows that as much as 73% of all athletes had recurrent ankle sprain and 59% of these athletes had significant disability and residual symptoms which led to impairment of their athletic performance. This study indicates that a pro...

  1. Relationship between navicular drop and measuring position of maximal plantar flexion torque of the first and second-fifth metatarsophalangeal joints.

    Science.gov (United States)

    Saeki, Junya; Tojima, Michio; Torii, Suguru

    2015-06-01

    [Purpose] The purpose of this study was to determine the relationship between navicular drop and plantar flexion torque of the first and second-fifth metatarsophalangeal joints. [Subjects] Ten healthy young men participated in this study. [Methods] The Pearson product-moment correlation coefficient was calculated to determine the relationship between navicular drop and plantar flexion torque of the first and second-fifth metatarsophalangeal joints. [Results] Significant negative correlations were observed between navicular drop and plantar flexion torques in the lengthened position of the intrinsic toe plantar flexion muscles, but no correlations were found between navicular drop and plantar flexion torques in the neutral position of the ankle and metatarsophalangeal joints. Moreover, the intrinsic toe plantar flexion muscles were found to contribute to the formation of the medial longitudinal arch. [Conclusion] Navicular drop correlates with metatarsophalangeal joint muscle strength in plantar flexion where the intrinsic toe muscles are capable of exerting force. PMID:26180323

  2. Ankle flexibility and injury patterns in dancers.

    Science.gov (United States)

    Wiesler, E R; Hunter, D M; Martin, D F; Curl, W W; Hoen, H

    1996-01-01

    Lower-extremity injuries are common among dancers and cause significant absences from rehearsals and performances. For this study of lower-extremity injuries in 101 ballet and 47 modern dance students, injuries requiring medical attention sustained over 1 academic year were associated with the following data obtained at the beginning of the school year: ankle flexibility, sex, dance discipline, previous injury, body mass index, and years of training. Eighty-three of the 148 students (age range, 12 to 28 years) reported prior lower-limb injuries, the most common being ankle sprains (28% of all dancers). Previous leg injuries correlated significantly with lower dorsiflexion measurements and with more new injuries. Female students had greater ankle and first metatarsophalangeal flexibility. Modern dancers had greater ankle inversion. Ninety-four students sustained 177 injuries during the study, including 75 sprains or strains and 71 cases of tendinitis. Thirty-nine percent (N = 69) were ankle injuries; 18% (N = 33) were knee injuries; 23% (N = 40) were foot injuries; and 20% (N = 35) were either hip or thigh injuries. Sixty-seven percent (N = 78) of the injured students were ballet dancers. Age, years of training, body mass index, sex, and ankle range of motion measurement had no predictive value for injury; previous injury and dance discipline both correlated with increased risk of injury. PMID:8947396

  3. Torque Sensors for Robot Joint Control

    OpenAIRE

    Tsetserukou, Dzmitry; Tachi, Susumu

    2008-01-01

    In Chapter, the stages of the joint torque sensor design are presented. New torque sensors for implementation of virtual backdrivability of robot joint transmissions have been developed. Torque measurement techniques, namely, electrical, electromagnetic, and optical, are discussed in detail. Technical requirements aimed at designing the highperformance torque sensor for humanoid robot arm were formulated. The substantial advantages of the optical technique motivated our choice in its favor. T...

  4. Forcing-dependent stability of steady turbulent states

    CERN Document Server

    Saint-Michel, Brice; Ravelet, Florent; Daviaud, François

    2013-01-01

    We study the influuence of the forcing on the steady turbulent states of a von K\\'arm\\'an swirling flow, at constant impeller speed, or at constant torque. We find that the different forcing conditions change the nature of the stability of the steady states and reveal dynamical regimes that bear similarities with low-dimensional systems. We suggest that this forcing dependence may be an out- of-equilibrium analogue of the ensemble inequivalence, valid for long-range interacting statistical systems, and that it may be applicable to other turbulent systems.

  5. An Improved Fixed Switching Frequency Direct Torque Control of Induction Motor Drives Fed by Direct Matrix Converter

    CERN Document Server

    Taib, Nabil; Francois, Bruno

    2010-01-01

    A few papers have been interested by the fixed switching frequency direct torque control fed by direct matrix converters, where we can find just the use of direct torque controlled space vector modulated method. In this present paper, we present an improved method used for a fixed switching frequency direct torque control (DTC) using a direct matrix converter (DMC). This method is characterized by a simple structure, a fixed switching frequency which causes minimal torque ripple and a unity input power factor. Using this strategy, we combine the direct matrix converters advantages with those of direct torque control (DTC) schemes. The used technique for constant frequency is combined with the input current space vector to create the switching table of direct matrix converter (DMC). Simulation results clearly demonstrate a better dynamic and steady state performances of the proposed method.

  6. The effect of isokinetic and proprioception training on strength, movement and gait parameters after acute supination injury of the ankle ligaments

    Directory of Open Access Journals (Sweden)

    C. Mucha

    2009-02-01

    Full Text Available The effects of a three-week isokinetic training compared to typical proprio -ceptive training on parameters of strength, movement and gait function after acute ankle ligament sprain were investigated. Thirty-nine patients were randomly allocated to two comparison groups. In group 1 (n=20a proprioceptive training and in group 2 (n=19 an isokinetic strength training (Cybex 6000® were administered. Thepatients of both groups underwent training five times a week for three weeks. Before and at the end of the treatmentcourse, in both groups isokinetic strength was tested, the range of motion in the ankle joint was recorded and gait wasanalyzed (multicomponent strength measurement platform, Henschel-System®. The maximum isokinetic torque(60°/s [Nm] and the contact time (monopedal support time of the injured leg during gait cycle were the basis for evaluation.The data obtained show that in group 2 a significantly greater increase of the maximum isokinetic torque wasattained in almost all range of motion of the ankle joint in the course of treatment. A t the same time, in group 2 theshortening of the contact time in the stance phase of the injured leg could be compensated. The active range of motionin the ankle joint was less at the end of treatment in group 2 than in group 1. The isokinetic training obviously did notonly lead to better strength regeneration, but also to a functionally more stable ankle joint with a rhythmically moreevenly balanced stance phase of the gait cycle.  These results suggest that the used isokinetic training had positive effects on functional stability after acute ankle sprain.

  7. Computerized Torque Control for Large dc Motors

    Science.gov (United States)

    Willett, Richard M.; Carroll, Michael J.; Geiger, Ronald V.

    1987-01-01

    Speed and torque ranges in generator mode extended. System of shunt resistors, electronic switches, and pulse-width modulation controls torque exerted by large, three-phase, electronically commutated dc motor. Particularly useful for motor operating in generator mode because it extends operating range to low torque and high speed.

  8. Measuring the uncertainty of tapping torque

    DEFF Research Database (Denmark)

    Belluco, Walter; De Chiffre, Leonardo

    An uncertainty budget is carried out for torque measurements performed at the Institut for Procesteknik for the evaluation of cutting fluids. Thirty test blanks were machined with one tool and one fluid, torque diagrams were recorded and the repeatability of single torque measurements was estimat...

  9. An EMG-Controlled SMA Device for the Rehabilitation of the Ankle Joint in Post-Acute Stroke

    Science.gov (United States)

    Pittaccio, S.; Viscuso, S.

    2011-07-01

    The capacity of flexing one's ankle is an indispensible segment of gait re-learning, as imbalance, wrong compensatory use of other joints and risk of falling may depend on the so-called drop-foot. The rehabilitation of ankle dorsiflexion may be achieved through active exercising of the relevant musculature (especially tibialis anterior, TA). This can be troublesome for patients affected by weakness and flaccid paresis. Thus, as needs evolve during patient's improvements, a therapeutic device should be able to guide and sustain gradual recovery by providing commensurate aid. This includes exploiting even initial attempts at voluntary motion and turns those into effective workout. An active orthosis powered by two rotary actuators containing NiTi wire was designed to obtain ankle dorsiflexion. A computer routine that analyzes the electromyographic (sEMG) signal from TA muscle is used to control the orthosis and trigger its activation. The software also provides instructions and feed-back for the patient. Tests on the orthosis proved that it can produce strokes up to 36° against resisting torques exceeding 180 Ncm. Three healthy subjects were able to control the orthosis by modulating their TA sEMG activity. The movement produced in the preliminary tests is interesting for lower limb rehabilitation, and will be further improved by optimizing body-orthosis interface. It is hoped that this device will enhance early rehabilitation and recovery of ankle mobility in stroke patients.

  10. Measurement of blood pressure, ankle blood pressure and calculation of ankle brachial index in general practice

    DEFF Research Database (Denmark)

    Nexøe, Jørgen; Damsbo, Bent; Lund, Jens Otto;

    2012-01-01

    BACKGROUND: Low ankle brachial index (ABI) is a sensitive measure of 'burden' of atherosclerosis, indicating cardiovascular risk of the asymptomatic patient. Conventionally, ABI values......BACKGROUND: Low ankle brachial index (ABI) is a sensitive measure of 'burden' of atherosclerosis, indicating cardiovascular risk of the asymptomatic patient. Conventionally, ABI values...

  11. Intramuscular pressure and torque during isometric, concentric and eccentric muscular activity

    Science.gov (United States)

    Styf, J.; Ballard, R.; Aratow, M.; Crenshaw, A.; Watenpaugh, D.; Hargens, A. R.

    1995-01-01

    Intramuscular pressures, electromyography (EMG) and torque generation during isometric, concentric and eccentric maximal isokinetic muscle activity were recorded in 10 healthy volunteers. Pressure and EMG activity were continuously and simultaneously measured side by side in the tibialis anterior and soleus muscles. Ankle joint torque and position were monitored continuously by an isokinetic dynamometer during plantar flexion and dorsiflexion of the foot. The increased force generation during eccentric muscular activity, compared with other muscular activity, was not accompanied by higher intramuscular pressure. Thus, this study demonstrated that eccentric muscular activity generated higher torque values for each increment of intramuscular pressure. Intramuscular pressures during antagonistic co-activation were significantly higher in the tibilis anterior muscle (42-46% of maximal agonistic activity) compared with the soleus muscle (12-29% of maximal agonistic activity) and was largely due to active recruitment of muscle fibers. In summary, eccentric muscular activity creates higher torque values with no additional increase of the intramuscular pressure compared with concentric and isometric muscular activity.

  12. Prospective study of ankle and foot fractures in elderly women

    Directory of Open Access Journals (Sweden)

    Yadagiri Surender Rao

    2015-01-01

    Full Text Available The epidemiology of ankle fractures in old people is changing as time passes on. The incidence of ankle fractures increases with advancing age. The study conducted was among a rural popula-tion which comprised of 68 women (32 women with ankle fractures & 36 women with foot fractures. Patients studied were in the age group more than 50 years. The study highlights the etiological & risk factors for fractures of ankle & foot. The commonest ankle fracture was the lateral malleolar fracture & the commonest foot fracture was the 5th Metatarsal fracture. Diabetes is a risk factor which increases the occurrence of ankle and foot injuries.

  13. Mechanical energy profiles of the combined ankle-foot system in normal gait: insights for prosthetic designs.

    Science.gov (United States)

    Takahashi, Kota Z; Stanhope, Steven J

    2013-09-01

    Over the last half-century, the field of prosthetic engineering has continuously evolved with much attention being dedicated to restoring the mechanical energy properties of ankle joint musculatures during gait. However, the contributions of 'distal foot structures' (e.g., foot muscles, plantar soft tissue) have been overlooked. Therefore, the purpose of this study was to quantify the total mechanical energy profiles (e.g., power, work, and work-ratio) of the natural ankle-foot system (NAFS) by combining the contributions of the ankle joint and all distal foot structures during stance in level-ground steady state walking across various speeds (0.4, 0.6, 0.8 and 1.0 statures/s). The results from eleven healthy subjects walking barefoot indicated ankle joint and distal foot structures generally performed opposing roles: the ankle joint performed net positive work that systematically increased its energy generation with faster walking speeds, while the distal foot performed net negative work that systematically increased its energy absorption with faster walking speeds. Accounting for these simultaneous effects, the combined ankle-foot system exhibited increased work-ratios with faster walking. Most notably, the work-ratio was not significantly greater than 1.0 during the normal walking speed of 0.8 statures/s. Therefore, a prosthetic design that strategically exploits passive-dynamic properties (e.g., elastic energy storage and return) has the potential to replicate the mechanical energy profiles of the NAFS during level-ground steady-state walking. PMID:23628408

  14. DTC-SVM Based on PI Torque and PI Flux Controllers to Achieve High Performance of Induction Motor

    Directory of Open Access Journals (Sweden)

    Hassan Farhan Rashag

    2014-01-01

    Full Text Available The fundamental idea of direct torque control of induction machines is investigated in order to emphasize the property produced by a given voltage vector on stator flux and torque variations. The proposed control system is based on Space Vector Modulation (SVM of electrical machines, Improvement model reference adaptive system, real time of stator resistance and estimation of stator flux. The purpose of this control is to minimize electromagnetic torque and flux ripple and minimizing distortion of stator current. In this proposed method, PI torque and PI flux controller are designed to achieve estimated torque and flux with good tracking and fast response with reference torque and there is no steady state error. In addition, design of PI torque and PI flux controller are used to optimize voltages in d-q reference frame that applied to SVM. The simulation Results of proposed DTC-SVM have complete excellent performance in steady and transient states as compared with classical DTC-SVM.

  15. Minimization of torque ripple in switched reluctance motor drives using direct instantaneous torque control

    OpenAIRE

    Castro Soriano, Javier; Andrada Gascón, Pedro; Blanqué Molina, Balduino

    2012-01-01

    Torque ripple is an inherent characteristic of switched reluctance motor drives due to its double salient geometry and it is a serious drawback in applications that require smooth torque and high dynamic performances. This paper presents some contributions to the minimization of torque ripple in SRM using direct instantaneous torque control (DITC). Direct torque controller is simulated using Matlab/Simulink and then implemented in a DSPACE ACE kit 1006 CLP that includes a processor boar...

  16. Comparison of three-level torque hysteresis controllers for direct torque control

    OpenAIRE

    Beerten, Jef; Verveckken, Jan; Driesen, Johan

    2009-01-01

    In this paper, a comparison is made between different implementations of the three-level torque comparator for a Direct Torque Control (DTC) based induction motor drive. The DTC scheme controls stator flux and torque by means of hysteresis comparators, respectively a two-level control structure for the stator flux and a three-level comparator for the electromagnetic torque. The standard three-level hysteresis controller has a DC offset torque error. In this paper, an additive implementation i...

  17. Minimization of torque ripple in switched reluctance motor drives using direct instantaneous torque

    OpenAIRE

    Castro Soriano, Javier; Andrada Gascón, Pedro; Blanqué Molina, Balduino

    2012-01-01

    Torque ripple is an inherent characteristic of switched reluctance motor drives due to its double salient geometry and it is a serious drawback in applications that require smooth torque and high dynamic performances. This paper presents some contributions to the minimization of torque ripple in SRM using direct instantaneous torque control (DITC). Direct torque controller is simulated using Matlab/Simulink and then implemented in a DSPACE ACE kit 1006 CLP that includes a processor b...

  18. A portable powered ankle-foot orthosis for rehabilitation.

    Science.gov (United States)

    Shorter, K Alex; Kogler, Géza F; Loth, Eric; Durfee, William K; Hsiao-Wecksler, Elizabeth T

    2011-01-01

    Innovative technological advancements in the field of orthotics, such as portable powered orthotic systems, could create new treatment modalities to improve the functional out come of rehabilitation. In this article, we present a novel portable powered ankle-foot orthosis (PPAFO) to provide untethered assistance during gait. The PPAFO provides both plantar flexor and dorsiflexor torque assistance by way of a bidirectional pneumatic rotary actuator. The system uses a portable pneumatic power source (compressed carbon dioxide bottle) and embedded electronics to control the actuation of the foot. We collected pilot experimental data from one impaired and three nondisabled subjects to demonstrate design functionality. The impaired subject had bilateral impairment of the lower legs due to cauda equina syndrome. We found that data from nondisabled walkers demonstrated the PPAFO's capability to provide correctly timed plantar flexor and dorsiflexor assistance during gait. Reduced activation of the tibialis anterior during stance and swing was also seen during assisted nondisabled walking trials. An increase in the vertical ground reaction force during the second half of stance was present during assisted trials for the impaired subject. Data from nondisabled walkers demonstrated functionality, and data from an impaired walker demonstrated the ability to provide functional plantar flexor assistance. PMID:21674394

  19. A portable powered ankle-foot orthosis for rehabilitation

    Directory of Open Access Journals (Sweden)

    K. Alex Shorter, PhD

    2011-05-01

    Full Text Available Innovative technological advancements in the field of orthotics, such as portable powered orthotic systems, could create new treatment modalities to improve the functional outcome of rehabilitation. In this article, we present a novel portablepowered ankle-foot orthosis (PPAFO to provide untethered assistance during gait. The PPAFO provides both plantar flexor and dorsiflexor torque assistance by way of a bidirectional pneumatic rotary actuator. The system uses a portable pneumatic power source (compressed carbon dioxide bottle and embedded electronics to control the actuation of the foot. We collected pilot experimental data from one impaired and three nondisabled subjects to demonstrate design functionality. The impaired subject had bilateral impairment of the lower legs due to cauda equina syndrome. We found that data from nondisabledwalkers demonstrated the PPAFO’s capability to provide correctlytimed plantar flexor and dorsiflexor assistance during gait. Reduced activation of the tibialis anterior during stance and swing was also seen during assisted nondisabled walking trials. An increase in the vertical ground reaction force during the second half of stance was present during assisted trials for the impaired subject. Data from nondisabled walkers demonstrated functionality, and data from an impaired walker demonstrated the ability to provide functional plantar flexor assistance.

  20. Clinical value of the Ottawa ankle rules for diagnosis of fractures in acute ankle injuries.

    Directory of Open Access Journals (Sweden)

    Xin Wang

    Full Text Available BACKGROUND: The Ottawa ankle rules (OAR are clinical decision guidelines used to identify whether patients with ankle injuries need to undergo radiography. The OAR have been proven that their application reduces unnecessary radiography. They have nearly perfect sensitivity for identifying clinically significant ankle fractures. OBJECTIVES: The purpose of this study was to assess the applicability of the OAR in China, to examine their accuracy for the diagnosis of fractures in patients with acute ankle sprains, and to assess their clinical utility for the detection of occult fractures. METHODS: In this prospective study, patients with acute ankle injuries were enrolled during a 6-month period. The eligible patients were examined by emergency orthopedic specialists using the OAR, and then underwent ankle radiography. The results of examination using the OAR were compared with the radiographic results to assess the accuracy of the OAR for ankle fractures. Patients with OAR results highly suggestive of fracture, but no evidence of a fracture on radiographs, were advised to undergo 3-dimensional computed tomography (3D-CT. RESULTS: 183 patients with ankle injuries were enrolled in the study and 63 of these injuries involved fractures. The pooled sensitivity, specificity, positive predictive value and negative predictive value of the OAR for detection of fractures of the ankle were 96.8%, 45.8%, 48.4% and 96.5%, respectively. Our results suggest that clinical application of the OAR could decrease unnecessary radiographs by 31.1%. Of the 21 patients with positive OAR results and negative radiographic findings who underwent 3D-CT examination, five had occult fractures of the lateral malleolus. CONCLUSIONS: The OAR are applicable in the Chinese population, and have high sensitivity and modest specificity for the diagnosis of fractures associated with acute ankle injury. They may detect some occult fractures of the malleoli that are not visible on

  1. Asynchronous Torque Characteristics of VR Type Vernier Motor

    Science.gov (United States)

    Suda, Hiroshi; Matsushima, Yoshitaro; Xu, Li; Anazawa, Yoshihisa

    Recently, various types of vernier motor are developed. The VR type vernier motor is a kind of three-phase reluctance motor, and its stator has slots and distributed three-phase windings. The rotor is slotted iron core without windings. Relationship between S, R and P is S = R±2, where S and R are the numbers of stator and rotor slots per pair of poles, and the number of poles P is two. The rotor of the vernier motor moves at a sub-multiple of the angular velocity of the stator mmf. The multiplying factor is P/R. Authors had reported that the VR type vernier motors are analyzed as a three-phase reluctance motor, and have obtained the voltage equations on the γ-δ axis and expression of the torque.However, the asynchronous characteristics of the vernier motor are not clear yet. In this paper, the asynchronous characteristics of the vernier motors are analyzed with the symmetric components transformation and the commutator transformation. The voltage equations on the symmetrical co-ordinates and asynchronous and synchronous torque expression at steady state condition are obtained. The tests were performed on the trial motor. The calculated asynchronous torque has agreed well with the measured values.

  2. Analysis of the Effects of Normal Walking on Ankle Joint Contact Characteristics After Acute Inversion Ankle Sprain.

    Science.gov (United States)

    Bae, Ji Yong; Park, Kyung Soon; Seon, Jong Keun; Jeon, Insu

    2015-12-01

    To show the causal relationship between normal walking after various lateral ankle ligament (LAL) injuries caused by acute inversion ankle sprains and alterations in ankle joint contact characteristics, finite element simulations of normal walking were carried out using an intact ankle joint model and LAL injury models. A walking experiment using a volunteer with a normal ankle joint was performed to obtain the boundary conditions for the simulations and to support the appropriateness of the simulation results. Contact pressure and strain on the talus articular cartilage and anteroposterior and mediolateral translations of the talus were calculated. Ankles with ruptured anterior talofibular ligaments (ATFLs) had a higher likelihood of experiencing increased ankle joint contact pressures, strains and translations than ATFL-deficient ankles. In particular, ankles with ruptured ATFL + calcaneofibular ligaments and all ruptured ankles had a similar likelihood as the ATFL-ruptured ankles. The push off stance phase was the most likely situation for increased ankle joint contact pressures, strains and translations in LAL-injured ankles. PMID:26077988

  3. Radiographic Evaluation of the Ankle Mortise

    Directory of Open Access Journals (Sweden)

    Hamid Mirbagheri

    2010-05-01

    Full Text Available The ankle joint is the most frequently injured joint in adults. Decisions on management are usually based on clinical examination and interpretation of the x-rays. Stability of the ankle mortise relies on the configuration of the osseous structures and the ligaments. A basic radiographic examination consists of a mortise-view and a lateral view. Some add the AP-view. The Mortise view is an AP-view with 15-25 degrees endorotation of the foot. "nThe view clearly demonstrates both lateral and medial joint spaces. On a true AP-view the talus overlaps a portion of the lateral malleolus obscuring the lateral aspect of the ankle joint. However, the AP-view will give you an extra view on both malleoli from a different angle. The lateral radiograph of the ankle should include the base of the fifth metatarsal because of the frequency of fractures at this side that clinically mimic a fracture of the ankle.

  4. Acute injury of the ankle joint

    International Nuclear Information System (INIS)

    The diagnosis of lateral collateral ankle ligament trauma is based on patient history, clinical examination, and clinical stress tests. If the clinical stress test is positive, stress radiography could be performed. There is no consensus about the usefulness of stress radiography in acute ankle sprain, particularly about the cut-off talar tilt angle beyond which a two-ligament rupture would be certain, ranging from 5 to 30 . Today MRI is not used for this indication, although it allows, with controlled positioning of the foot and with defined sections, visualization of injured lateral collateral ankle ligaments. In ankle injuries, plain radiographs form the established basis of diagnostic imaging and can provide definitive answers in most cases. CT is used in complex fractures for complete visualization. MRI is the method of choice for several diagnostic problem cases, including occult fractures and post-traumatic avascular necrosis. In tendon injuries, MRI is important if ultrasound is not diagnostic. Generally, for the evaluation of acute ankle injuries, MRI is the most important second-step procedure when radiographs are nondiagnostic. (orig.)

  5. Sprained Ankle Could Pose Longer-Term Harms to Health

    Science.gov (United States)

    ... them said they had sustained some kind of ankle injury at some point in their lives. Those who' ... taken more seriously, the researchers said. "In isolation, ankle injuries are seen as relatively benign and inconsequential injuries," ...

  6. Sensorless torque/force control

    OpenAIRE

    KHALIL, Islam Shoukry Mohammed; Şabanoviç, Asif; SABANOVIC, Asif

    2011-01-01

    Motion control systems represent a main subsystem for majority of processing systems that can be found in the industrial sector. These systems are concerned with the actuation of all devices in the manufacturing process such as machines, robots, conveyor systems and pick and place mechanisms such that they satisfy certain motion requirements, e.g., the pre specified reference trajectories are followed along with delivering the proper force or torque to the point of interest at which the proce...

  7. Low-Torque Seal Development

    Science.gov (United States)

    Lattime, Scott B.; Borowski, Richard

    2009-01-01

    The EcoTurn Class K production prototypes have passed all AAR qualification tests and received conditional approval. The accelerated life test on the second set of seals is in progress. Due to the performance of the first set, no problems are expected.The seal has demonstrated superior performance over the HDL seal in the test lab with virtually zero torque and excellent contamination exclusion and grease retention.

  8. Space Suit Joint Torque Testing

    Science.gov (United States)

    Valish, Dana J.

    2011-01-01

    In 2009 and early 2010, a test was performed to quantify the torque required to manipulate joints in several existing operational and prototype space suits in an effort to develop joint torque requirements appropriate for a new Constellation Program space suit system. The same test method was levied on the Constellation space suit contractors to verify that their suit design meets the requirements. However, because the original test was set up and conducted by a single test operator there was some question as to whether this method was repeatable enough to be considered a standard verification method for Constellation or other future space suits. In order to validate the method itself, a representative subset of the previous test was repeated, using the same information that would be available to space suit contractors, but set up and conducted by someone not familiar with the previous test. The resultant data was compared using graphical and statistical analysis and a variance in torque values for some of the tested joints was apparent. Potential variables that could have affected the data were identified and re-testing was conducted in an attempt to eliminate these variables. The results of the retest will be used to determine if further testing and modification is necessary before the method can be validated.

  9. Isolated posterior high ankle sprain: a report of three cases.

    Science.gov (United States)

    Botchu, Rajesh; Allen, Patricia; Rennie, Winston J

    2013-12-01

    High ankle sprains are difficult to diagnose and account for 10% of all ankle sprains. A high index of suspicion is essential for diagnosis. High ankle sprains are managed symptomatically, with prolonged rehabilitation. The posterior inferior tibiofibular ligament is the strongest syndesmotic ligament; isolated injury of it is rare. We present 3 cases of isolated posterior high ankle sprain and discuss the relevant anatomy, mechanism of injury, and management. PMID:24366808

  10. The Effects of Kinesio™ Taping on Proprioception at the Ankle

    OpenAIRE

    Mark DeBeliso; Ross Vaughn; Jeff Lien; McChesney, John W.; Travis Halseth

    2004-01-01

    An experiment was designed to determine if KinesioTM taping the anterior and lateral portion of the ankle would enhance ankle proprioception compared to the untaped ankle. 30 subjects, 15 men, 15 women, ages 18-30 participated in this study. Exclusion criteria: Ankle injury < 6 months prior to testing, significant ligament laxity as determined through clinical evaluation by an ATC, or any severe foot abnormality. Experiment utilized a single group, pretest and posttest. Plantar flexion and in...

  11. Development and Reliability of the Ankle Instability Instrument

    OpenAIRE

    Docherty, Carrie L; Gansneder, Bruce M; Arnold, Brent L; Hurwitz, Shepard R.

    2006-01-01

    Context: Functional ankle instability has been defined in a variety of ways. Factors that are frequently used in this definition include a history of a severe ankle sprain, a history of multiple ankle sprains, and a recurrent feeling of instability or “giving way.” With all the variations in defining functional ankle instability, it becomes increasingly important to develop a more consistent framework for assessing this instability.

  12. Anterolateralni utesnitveni sindrom gležnja: Ankle impingement syndrome:

    OpenAIRE

    Frangež, Igor; Senekovič, Vladimir; Žnidaršič, Marta

    2011-01-01

    lnversion injuries of the ankle are common and most are managed adequately by functional treatment. A significant number will, however, remain symptomatic. Ankle impingement syndrome is clinicaly evident as pain, which is elicited by full range of motion in ankle joint because of the mechanical impidgement in the joint. Ankle impingement can result from trauma, infection, inflammation or from degenerative process. The impingement syndrome can be anterolateral, anteromedial, posterior, made of...

  13. Validation of the Ottawa ankle rules in children.

    OpenAIRE

    Libetta, C; Burke, D; Brennan, P; Yassa, J

    1999-01-01

    OBJECTIVE: To assess whether the Ottawa ankle rules can be used to accurately predict which children with ankle and midfoot injuries need radiography. METHODS: Prospective study with historical control group of all children aged 1-15 years presenting to Sheffield Children's Hospital accident and emergency department with blunt ankle and/or midfoot injuries during two five month periods before and after implementation of the Ottawa ankle rules. RESULTS: In the study group 432 out of 761 (56.76...

  14. RMI study and clinical correlations of ankle retinacula damage and outcomes of ankle sprain.

    Science.gov (United States)

    Stecco, Antonio; Stecco, Carla; Macchi, Veronica; Porzionato, Andrea; Ferraro, Claudio; Masiero, Stefano; De Caro, Raffaele

    2011-12-01

    Recent studies reveal the role of the ankle retinacula in proprioception and functional stability of the ankle, but there is no clear evidence of their role in the outcomes of ankle sprain. 25 patients with outcomes of ankle sprain were evaluated by MRI to analyze possible damage to the ankle retinacula. Patients with damage were subdivided into two groups: group A comprised cases with ankle retinacula damage only, and group B those also with anterior talofibular ligament rupture or bone marrow edema. Both groups were examined by VAS, CRTA and static posturography and underwent three treatments of deep connective tissue massage (Fascial Manipulation technique). All evaluations were repeated after the end of treatment and at 1, 3 and 6 months. At MRI, alteration of at least one of the ankle retinacula was evident in 21 subjects, and a further lesion was also identified in 7 subjects. After treatment, VAS and CRTA evaluations showed a statistically significant decrease in values with respect to those before treatment (p stabilometric platform results. No significant difference was found between groups A and B. The initial benefit was generally maintained at follow-up. The alteration of retinacula at MRI clearly corresponds to the proprioceptive damage revealed by static posturography and clinical examination. Treatment focused on the retinacula may improve clinical outcomes and stabilometric data. PMID:21305286

  15. Direct torque control of six-phase induction motors using three-phase matrix converter

    Energy Technology Data Exchange (ETDEWEB)

    Talaeizadeh, V., E-mail: valitalaeezadeh@yahoo.co [Shahid Chamran University of Ahvaz, Ahvaz (Iran, Islamic Republic of); Kianinezhad, R.; Seyfossadat, S.G. [Shahid Chamran University of Ahvaz, Ahvaz (Iran, Islamic Republic of); Shayanfar, H.A. [The Center of Excellence for Power System Automation and Operation, Department of Electrical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)

    2010-12-15

    This paper presents a new direct torque control (DTC) method for six-phase induction motor (SPIM). In the proposed method, direct torque and flux control are applied to the SPIM using matrix converter with the conventional three-phase source as its input. The new DTC scheme for SPIM benefits the advantages of both DTC and matrix converter, such as unity power factor and absence of dc-link. The simulation results show the effectiveness of the proposed method in both dynamic and steady state response.

  16. Direct torque control of six-phase induction motors using three-phase matrix converter

    International Nuclear Information System (INIS)

    This paper presents a new direct torque control (DTC) method for six-phase induction motor (SPIM). In the proposed method, direct torque and flux control are applied to the SPIM using matrix converter with the conventional three-phase source as its input. The new DTC scheme for SPIM benefits the advantages of both DTC and matrix converter, such as unity power factor and absence of dc-link. The simulation results show the effectiveness of the proposed method in both dynamic and steady state response.

  17. New concept of direct torque neuro-fuzzy control for induction motor drives. Simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Grabowski, P.Z. [Institute of Control and Industrial Electronics, Warsaw University of Technology, Warsaw (Poland)

    1997-12-31

    This paper presents a new control strategy in the discrete Direct Torque Control (DTC) based on neuro-fuzzy structure. Two schemes are proposed: neuro-fuzzy switching times calculator and neuro-fuzzy incremental controller with space vector modulator. These control strategies guarantee very good dynamic and steady-states characteristics, with very low sampling time and constant switching frequency. The proposed techniques are verified by simulation study of the whole drive system and results are compared with conventional discrete Direct Torque Control method. (orig.) 18 refs.

  18. Search the Foot and Ankle: Interactive Foot Diagram

    Science.gov (United States)

    ... of the Fifth Metatarsal » Ganglion Cyst » Lisfranc Injuries » Posterior Tibial Tendon Dysfunction (PTTD) » Tarsal Coalition » Ankle Fractures » Ankle Sprain » Chronic Ankle Instability » Equinus » Gout » Posterior Tibial Tendon Dysfunction (PTTD) » Talar Dome Lesion » Bunions (Hallux ...

  19. Robotics and gaming to improve ankle strength, motor control, and function in children with cerebral palsy--a case study series.

    Science.gov (United States)

    Burdea, Grigore C; Cioi, Daniel; Kale, Angad; Janes, William E; Ross, Sandy A; Engsberg, Jack R

    2013-03-01

    The objective of this study was to investigate the feasibility of game-based robotic training of the ankle in children with cerebral palsy (CP). The design was a case study, 12 weeks intervention, with no follow-up. The setting was a university research laboratory. The participants were a referred sample of three children with cerebral palsy, age 7-12, all male. All completed the intervention. Participants trained on the Rutgers Ankle CP system for 36 rehabilitation sessions (12 weeks, three times/week), playing two custom virtual reality games. The games were played while participants were seated, and trained one ankle at-a-time for strength, motor control, and coordination. The primary study outcome measures were for impairment (DF/PF torques, DF initial contact angle and gait speed), function (GMFM), and quality of life (Peds QL). Secondary outcome measures relate to game performance (game scores as reflective of ankle motor control and endurance). Gait function improved substantially in ankle kinematics, speed and endurance. Overall function (GMFM) indicated improvements that were typical of other ankle strength training programs. Quality of life increased beyond what would be considered a minimal clinical important difference. Game performance improved in both games during the intervention. This feasibility study supports the assumption that game-based robotic training of the ankle benefits gait in children with CP. Game technology is appropriate for the age group and was well accepted by the participants. Additional studies are needed however, to quantify the level of benefit and compare the approach presented here to traditional methods of therapy. PMID:22773059

  20. Design and Preliminary Evaluation of a Two DOFs Cable-Driven Ankle-Foot Prosthesis with Active Dorsiflexion-Plantarflexion and Inversion-Eversion.

    Science.gov (United States)

    Ficanha, Evandro Maicon; Ribeiro, Guilherme Aramizo; Dallali, Houman; Rastgaar, Mohammad

    2016-01-01

    This paper describes the design of an ankle-foot robotic prosthesis controllable in the sagittal and frontal planes. The prosthesis was designed to meet the mechanical characteristics of the human ankle including power, range of motion, and weight. To transfer the power from the motors and gearboxes to the ankle-foot mechanism, a Bowden cable system was used. The Bowden cable allows for optimal placement of the motors and gearboxes in order to improve gait biomechanics such as the metabolic energy cost and gait asymmetry during locomotion. Additionally, it allows flexibility in the customization of the device to amputees with different residual limb sizes. To control the prosthesis, impedance controllers in both sagittal and frontal planes were developed. The impedance controllers used torque feedback from strain gages installed on the foot. Preliminary evaluation was performed to verify the capability of the prosthesis to track the kinematics of the human ankle in two degrees of freedom (DOFs), the mechanical efficiency of the Bowden cable transmission, and the ability of the prosthesis to modulate the impedance of the ankle. Moreover, the system was characterized by describing the relationship between the stiffness of the impedance controllers to the actual stiffness of the ankle. Efficiency estimation showed 85.4% efficiency in the Bowden cable transmission. The prosthesis was capable of properly mimicking human ankle kinematics and changing its mechanical impedance in two DOFs in real time with a range of stiffness sufficient for normal human walking. In dorsiflexion-plantarflexion (DP), the stiffness ranged from 0 to 236 Nm/rad and in inversion-eversion (IE), the stiffness ranged from 1 to 33 Nm/rad. PMID:27200342

  1. A Novel Design for Adjustable Stiffness Artificial Tendon for the Ankle Joint of a Bipedal Robot: Modeling & Simulation

    Directory of Open Access Journals (Sweden)

    Aiman Omer

    2015-12-01

    Full Text Available Bipedal humanoid robots are expected to play a major role in the future. Performing bipedal locomotion requires high energy due to the high torque that needs to be provided by its legs’ joints. Taking the WABIAN-2R as an example, it uses harmonic gears in its joint to increase the torque. However, using such a mechanism increases the weight of the legs and therefore increases energy consumption. Therefore, the idea of developing a mechanism with adjustable stiffness to be connected to the leg joint is introduced here. The proposed mechanism would have the ability to provide passive and active motion. The mechanism would be attached to the ankle pitch joint as an artificial tendon. Using computer simulations, the dynamical performance of the mechanism is analytically evaluated.

  2. Comparison of Knee and Ankle Dynamometry between NASA's X1 Exoskeleton and Biodex System 4

    Science.gov (United States)

    English, K. L.; Newby, N. J.; Hackney, K. J.; DeWitt, J. K.; Beck, C. E.; Rovekamp, R. N.; Rea, R. L.; Ploutz-Snyder, L. L.

    2014-01-01

    high agreement between devices; KF did not. For ankle PF, torque differences due to the two footplates were small. However, the X1 motor reports greater torques than the Biodex motor during PF. This first prototype provides proof of concept for a reliable, robotic-based exoskeleton to perform portable dynamometry for large muscle groups of the lower body.

  3. The role of interaction torque and muscle torque in the control of downward squatting.

    Science.gov (United States)

    Fujisawa, Hiroyuki; Suzuki, Hiroto; Murakami, Kenichi; Kawakami, Shingo; Suzuki, Makoto

    2016-01-01

    [Purpose] The purposes of this study were first to analyze the multijoint dynamics of downward squatting, and to examine the contribution of interaction torque and muscle torque to net torque, and second, to examine mechanisms of movement control. [Subjects] The subjects were 31 healthy men with a mean age of 21.0 ± 1.2 years (range, 19-24 years). [Methods] Squatting tasks with the trunk in two positions, an erect and anterior tilt position, were performed by the subjects. Net, interaction, muscle, and gravity torque were calculated according to the Lagrange equation using 3D tracking data. [Results] The contribution ratio of interaction torque to net torque was approximately 90%, irrespective of the joint and task. In contrast, muscle torque showed complicated behavior to compensate for gravity torque. A combined muscle and gravity torque profile showed flexion or dorsiflexion immediately after the initiation of the movement, and it later changed to extension or plantar flexion. [Conclusion] The torque that contributes almost exclusively to the net torque was interaction torque. The combination of muscle and gravity torque at the knee joint and the hip joint is important for movement control, independent of the starting position. PMID:27065552

  4. The effects of powered ankle-foot orthoses on joint kinematics and muscle activation during walking in individuals with incomplete spinal cord injury

    Directory of Open Access Journals (Sweden)

    Domingo Antoinette

    2006-02-01

    Full Text Available Abstract Background Powered lower limb orthoses could reduce therapist labor during gait rehabilitation after neurological injury. However, it is not clear how patients respond to powered assistance during stepping. Patients might allow the orthoses to drive the movement pattern and reduce their muscle activation. The goal of this study was to test the effects of robotic assistance in subjects with incomplete spinal cord injury using pneumatically powered ankle-foot orthoses. Methods Five individuals with chronic incomplete spinal cord injury (ASIA C-D participated in the study. Each subject was fitted with bilateral ankle-foot orthoses equipped with artificial pneumatic muscles to power ankle plantar flexion. Subjects walked on a treadmill with partial bodyweight support at four speeds (0.36, 0.54, 0.72 and 0.89 m/s under three conditions: without wearing orthoses, wearing orthoses unpowered (passively, and wearing orthoses activated under pushbutton control by a physical therapist. Subjects also attempted a fourth condition wearing orthoses activated under pushbutton control by them. We measured joint angles, electromyography, and orthoses torque assistance. Results A therapist quickly learned to activate the artificial pneumatic muscles using the pushbuttons with the appropriate amplitude and timing. The powered orthoses provided ~50% of peak ankle torque. Ankle angle at stance push-off increased when subjects walked with powered orthoses versus when they walked with passive-orthoses (ANOVA, p Two of the five subjects were able to control the orthoses themselves using the pushbuttons. The other three subjects found it too difficult to coordinate pushbutton timing. Orthoses assistance and maximum ankle angle at push-off were smaller when the subject controlled the orthoses compared to when the therapist-controlled the orthoses (p Conclusion Mechanical assistance from powered ankle-foot orthoses improved ankle push-off kinematics without

  5. Vibration-induced extra torque during electrically-evoked contractions of the human calf muscles

    Directory of Open Access Journals (Sweden)

    Kohn André F

    2010-06-01

    Full Text Available Abstract Background High-frequency trains of electrical stimulation applied over the lower limb muscles can generate forces higher than would be expected from a peripheral mechanism (i.e. by direct activation of motor axons. This phenomenon is presumably originated within the central nervous system by synaptic input from Ia afferents to motoneurons and is consistent with the development of plateau potentials. The first objective of this work was to investigate if vibration (sinusoidal or random applied to the Achilles tendon is also able to generate large magnitude extra torques in the triceps surae muscle group. The second objective was to verify if the extra torques that were found were accompanied by increases in motoneuron excitability. Methods Subjects (n = 6 were seated on a chair and the right foot was strapped to a pedal attached to a torque meter. The isometric ankle torque was measured in response to different patterns of coupled electrical (20-Hz, rectangular 1-ms pulses and mechanical stimuli (either 100-Hz sinusoid or gaussian white noise applied to the triceps surae muscle group. In an additional investigation, Mmax and F-waves were elicited at different times before or after the vibratory stimulation. Results The vibratory bursts could generate substantial self-sustained extra torques, either with or without the background 20-Hz electrical stimulation applied simultaneously with the vibration. The extra torque generation was accompanied by increased motoneuron excitability, since an increase in the peak-to-peak amplitude of soleus F waves was observed. The delivery of electrical stimulation following the vibration was essential to keep the maintained extra torques and increased F-waves. Conclusions These results show that vibratory stimuli applied with a background electrical stimulation generate considerable force levels (up to about 50% MVC due to the spinal recruitment of motoneurons. The association of vibration and electrical

  6. Permanent-magnet flux-switching integrated starter generator with different rotor configurations for cogging torque and torque ripple mitigations

    OpenAIRE

    Fei, Wei-Zhong; Luk, Patrick Chi-Kwong; Shen, Jian-xin; Xia, Bin; Wang, Yu

    2011-01-01

    This paper investigates the cogging torque and torque ripple features of a permanent-magnet flux-switching integrated starter generator. The effects of the rotor pole arc width on the cogging torque, torque ripple, and output torque are first established using finite-element analysis (FEA). Three torque ripple reduction techniques based on the optimization of three different rotor pole configurations, namely, uniform, step skewed, and axial pairing, are then proposed. The torque characteristi...

  7. TORQUE MEASUREMENT IN WORM AGLOMERATION MACHINE

    Directory of Open Access Journals (Sweden)

    Marian DUDZIAK

    2014-03-01

    Full Text Available The paper presents the operating characteristics of the worm agglomeration machine. The paper indicates the need for continuous monitoring of the value of the torque due to the efficiency of the machine. An original structure of torque meter which is built in the standard drive system of briquetting machine was presented. A number of benefits arising from the application of the proposed solution were presented. Exemplary measurement results obtained by means of this torque meter were presented.

  8. TORQUE MEASUREMENT IN WORM AGLOMERATION MACHINE

    OpenAIRE

    Marian DUDZIAK; Ireneusz MALUJDA; Krzysztof TALAŚKA

    2014-01-01

    The paper presents the operating characteristics of the worm agglomeration machine. The paper indicates the need for continuous monitoring of the value of the torque due to the efficiency of the machine. An original structure of torque meter which is built in the standard drive system of briquetting machine was presented. A number of benefits arising from the application of the proposed solution were presented. Exemplary measurement results obtained by means of this torque meter were presented.

  9. A surgical ankle sprain pain model in the rat: Effects of morphine and indomethacin

    OpenAIRE

    Young Kim, Hee; Wang, Jigong; Chung, Kyungsoon; Mo Chung, Jin

    2008-01-01

    Ankle sprain is a frequent injury in humans that results in pain, swelling and difficulty in walking on the affected ankle. Currently a suitable animal model resembling human ankle sprain is lacking. Here, we describe an animal ankle sprain model induced by ankle ligament injury (ALI) in rats. Cutting combinations of the lateral ankle ligament complex produced pain, edema and difficulty of weight bearing, thereby mimicking severe (grade III) ankle sprain in humans. Analgesic compounds, morphi...

  10. Short-term ankle motor performance with ankle robotics training in chronic hemiparetic stroke

    Directory of Open Access Journals (Sweden)

    Anindo Roy, PhD

    2011-05-01

    Full Text Available Cerebrovascular accident (stroke often results in impaired motor control and persistent weakness that may lead to chronic disability, including deficits in gait and balance function. Finding ways to restore motor control may help reduce these deficits; however, little is known regarding the capacity or temporal profile of short-term motor adaptations and learning at the hemiparetic ankle. Our objective was to determine the short-term effects of a single session of impedance-controlled ankle robot (“anklebot” training on paretic ankle motor control in chronic stroke. This was a double-arm pilot study on a convenience sample of participants with chronic stroke (n = 7 who had residual hemiparetic deficits and an equal number of age- and sex-matched nondisabled control subjects. Training consisted of participants in each group playing a target-based video game with the anklebot for an hour, for a total of 560 movement repetitions in dorsiflexion/plantar flexion ranges followed by retest 48 hours later. Task difficulty was adjusted to ankle range of motion, with robotic assistance decreased incrementally across training. Assessments included robotic measures of ankle motor control on unassisted trials before and after training and at 48 hours after training. Following exposure to the task, subjects with stroke improved paretic ankle motor control across a single training session as indexed by increased targeting accuracy (21.6 +/– 8.0 to 31.4 +/– 4.8, p = 0.05, higher angular speeds (mean: 4.7 +/– 1.5 degrees/s to 6.5 +/– 2.6 degrees/s, p 0.05 at 48 hours in both groups. Robust maintenance of motor adaptation in the robot-trained paretic ankle over 48 hours may be indicative of short-term motor learning. Our initial results suggest that the anklebot may be a flexible motor learning platform with the potential to detect rapid changes in ankle motor performance poststroke.

  11. Three-dimensional magnetic resonance imaging for ruptures of the lateral ligaments of the ankle

    International Nuclear Information System (INIS)

    The accuracy has been determined of three-dimensional MRI in visualizing the anterior talofibular and the calcaneofibular ligament in young athletes with an acute severe sprain of the lateral ligaments of the ankle by comparing these findings with those found at operation and evaluating three-dimensional fast imaging with steady state precession (3D FISP) as a diagnostic aid to operative planning for tears of both the anterior talofibular and the calcaneofibular ligament in younger competitive athletes. (author). 20 refs.; 2 figs

  12. A universal ankle-foot prosthesis emulator for human locomotion experiments.

    Science.gov (United States)

    Caputo, Joshua M; Collins, Steven H

    2014-03-01

    Robotic prostheses have the potential to significantly improve mobility for people with lower-limb amputation. Humans exhibit complex responses to mechanical interactions with these devices, however, and computational models are not yet able to predict such responses meaningfully. Experiments therefore play a critical role in development, but have been limited by the use of product-like prototypes, each requiring years of development and specialized for a narrow range of functions. Here we describe a robotic ankle-foot prosthesis system that enables rapid exploration of a wide range of dynamical behaviors in experiments with human subjects. This emulator comprises powerful off-board motor and control hardware, a flexible Bowden cable tether, and a lightweight instrumented prosthesis, resulting in a combination of low mass worn by the human (0.96 kg) and high mechatronic performance compared to prior platforms. Benchtop tests demonstrated closed-loop torque bandwidth of 17 Hz, peak torque of 175 Nm, and peak power of 1.0 kW. Tests with an anthropomorphic pendulum "leg" demonstrated low interference from the tether, less than 1 Nm about the hip. This combination of low worn mass, high bandwidth, high torque, and unrestricted movement makes the platform exceptionally versatile. To demonstrate suitability for human experiments, we performed preliminary tests in which a subject with unilateral transtibial amputation walked on a treadmill at 1.25 ms-1 while the prosthesis behaved in various ways. These tests revealed low torque tracking error (RMS error of 2.8 Nm) and the capacity to systematically vary work production or absorption across a broad range (from -5 to 21 J per step). These results support the use of robotic emulators during early stage assessment of proposed device functionalities and for scientific study of fundamental aspects of human-robot interaction. The design of simple, alternate end-effectors would enable studies at other joints or with

  13. Medial gastrocnemius muscle fascicle active torque-length and Achilles tendon properties in young adults with spastic cerebral palsy.

    Science.gov (United States)

    Barber, Lee; Barrett, Rod; Lichtwark, Glen

    2012-10-11

    Individuals with spastic cerebral palsy (CP) typically experience muscle weakness. The mechanisms responsible for muscle weakness in spastic CP are complex and may be influenced by the intrinsic mechanical properties of the muscle and tendon. The purpose of this study was to investigate the medial gastrocnemius (MG) muscle fascicle active torque-length and Achilles tendon properties in young adults with spastic CP. Nine relatively high functioning young adults with spastic CP (GMFCS I, 17±2 years) and 10 typically developing individuals (18±2 years) participated in the study. Active MG torque-length and Achilles tendon properties were assessed under controlled conditions on a dynamometer. EMG was recorded from leg muscles and ultrasound was used to measure MG fascicle length and Achilles tendon length during maximal isometric contractions at five ankle angles throughout the available range of motion and during passive rotations imposed by the dynamometer. Compared to the typically developing group, the spastic CP group had 33% lower active ankle plantarflexion torque across the available range of ankle joint motion, partially explained by 37% smaller MG muscle and 4% greater antagonistic co-contraction. The Achilles tendon slack length was also 10% longer in the spastic CP group. This study confirms young adults with mild spastic CP have altered muscle-tendon mechanical properties. The adaptation of a longer Achilles tendon may facilitate a greater storage and recovery of elastic energy and partially compensate for decreased force and work production by the small muscles of the triceps surae during activities such as locomotion. PMID:22867763

  14. [Ankle sprain during a volleyball game].

    Science.gov (United States)

    Boersma, Anton R; Munzebrock, Arvid V E

    2015-01-01

    A 27-year old woman was admitted to the emergency room after her left ankle rolled inward during a volleyball game. On physical examination a bony prominence on the lateral side of the left foot was noticeable, without neurovascular injury. An X-ray (anterior-posterior view) showed a subtalar dislocation without associated fractures. PMID:26420145

  15. Injury of the ankle joint ligaments

    International Nuclear Information System (INIS)

    The diagnosis of lateral collateral ankle ligament trauma is based on patient history, clinical examination and clinical stress tests. If the clinical stress test is positive, stress radiography can be performed. There is, however, no consensus about the usefulness of stress radiography in acute ankle sprain, and in particular about the cut-off talar tilt angle beyond which a two-ligament rupture would be certain, ranging from 5 to 30 . Today, magnetic resonance imaging (MRI) is not used in this area, although it does allow controlled positioning of the foot and defined section visualization of injured lateral collateral ankle ligaments. In acute and chronic sinus tarsi injuries, MRI forms the established basis for diagnostic imaging, and can provide a definitive answer in most cases. MRI is also the method of choice for chronic posttraumatic pain with anterolateral impingement after rupture of the anterior talofibular ligament. Generally, for the evaluation of acute ankle injuries, MRI has developed to be the most important second-step procedure when projection radiology is non-diagnostic. (orig.)

  16. Interfacial spin-orbit splitting and current-driven spin torque in anisotropic tunnel junctions

    KAUST Repository

    Manchon, Aurelien

    2011-05-17

    Spin transport in magnetic tunnel junctions comprising a single magnetic layer in the presence of interfacial spin-orbit interaction (SOI) is investigated theoretically. Due to the presence of interfacial SOI, a current-driven spin torque can be generated at the second order in SOI, even in the absence of an external spin polarizer. This torque possesses two components, one in plane and one perpendicular to the plane of rotation, that can induce either current-driven magnetization switching from an in-plane to out-of-plane configuration or magnetization precessions, similar to spin transfer torque in spin valves. Consequently, it appears that it is possible to control the magnetization steady state and dynamics by either varying the bias voltage or electrically modifying the SOI at the interface.

  17. Control of fracture reduction robot using force/torque measurement.

    Science.gov (United States)

    Douke, T; Nakajima, Y; Mori, Y; Onogi, S; Sugita, N; Mitsuishi, M; Bessho, M; Ohhashi, S; Tobita, K; Ohnishi, I; Sakuma, I; Dohi, T; Maeda, Y; Koyama, T; Sugano, N; Yonenobu, K; Matsumoto, Y; Nakamura, K

    2008-01-01

    We have developed a surgical robotic system for femoral fracture reduction employing indirect traction. Indirect traction in fracture reduction is a generally used surgical method for preventing complications such as bone splits caused by high stress on bones. For traction, a patient's foot is gripped by a jig and pulled to the distal side. Indirect traction has the advantage of distributing bone stress by utilizing a strong traction force; however, this procedure does not accurately control the proper positioning of fractured fragments when a surgical robot is used. The human leg has knee and an ankle joints, and thus robotic motion presents problems in not being able to directly propagate reduction motion to a fractured femoral fragment, rendering control of bone position difficult. We propose a control method for fracture reduction robots using external force/torque measurements of the human leg to achieve precise fracture reduction. Results showed that the proposed method reduced repositioning error from 6.8 mm and 15.9 degrees to 0.7 mm and 5.3 degrees, respectively. PMID:19163404

  18. Spin Orbit Torque in Ferromagnetic Semiconductors

    KAUST Repository

    Li, Hang

    2016-06-21

    Electrons not only have charges but also have spin. By utilizing the electron spin, the energy consumption of electronic devices can be reduced, their size can be scaled down and the efficiency of `read\\' and `write\\' in memory devices can be significantly improved. Hence, the manipulation of electron spin in electronic devices becomes more and more appealing for the advancement of microelectronics. In spin-based devices, the manipulation of ferromagnetic order parameter using electrical currents is a very useful means for current-driven operation. Nowadays, most of magnetic memory devices are based on the so-called spin transfer torque, which stems from the spin angular momentum transfer between a spin-polarized current and the magnetic order parameter. Recently, a novel spin torque effect, exploiting spin-orbit coupling in non-centrosymmetric magnets, has attracted a massive amount of attention. This thesis addresses the nature of spin-orbit coupled transport and torques in non-centrosymmetric magnetic semiconductors. We start with the theoretical study of spin orbit torque in three dimensional ferromagnetic GaMnAs. Using the Kubo formula, we calculate both the current-driven field-like torque and anti-damping-like torque. We compare the numerical results with the analytical expressions in the model case of a magnetic Rashba two-dimensional electron gas. Parametric dependencies of the different torque components and similarities to the analytical results of the Rashba two-dimensional electron gas in the weak disorder limit are described. Subsequently we study spin-orbit torques in two dimensional hexagonal crystals such as graphene, silicene, germanene and stanene. In the presence of staggered potential and exchange field, the valley degeneracy can be lifted and we obtain a valley-dependent Berry curvature, leading to a tunable antidamping torque by controlling the valley degree of freedom. This thesis then addresses the influence of the quantum spin Hall

  19. A multimodal approach to ankle instability: Interrelations between subjective and objective assessments of ankle status in athletes.

    Science.gov (United States)

    Golditz, Tobias; Welsch, Goetz H; Pachowsky, Milena; Hennig, Friedrich F; Pfeifer, Klaus; Steib, Simon

    2016-03-01

    The aim of this retrospective cohort study is to investigate the association between different subjective and objective assessments of ankle function in a population of athletes with or without functional ankle instability (FAI). 29 athletes with a history of ankle spraining were divided into two groups according to their ankle status: 16 with FAI (initial ankle sprain with residual functional instability) (age 24.6 ± 3.1 years), and 13 COPERS (initial ankle sprain without residual instability) (age 25.3 ± 4.4 years). The assessment of each individual's ankle function was based on three approaches: The "functional-ankle-ability-measure" (FAAM) assessing subjective ankle functionality, measures of sensorimotor control as objective functional measurements and MRI-based T2-mapping as a quantitative marker of compositional joint status. Pearson's product-moment-correlation coefficient, student's t-test and analysis-of-variance were used for statistical analysis. Significant group differences existed for subjective ankle function (FAAM, p = 0.04) and MRI-data mainly in the medial compartment of the ankle joint (p ≤ 0.05). We found unique associations between T2-mapping results and sensorimotor scores in the COPER (r = -0.756-0.849), and "FAI"-group (r = 0.630-0.657). The location and magnitude differed between groups. No correlations existed between these measures and the FAAM. This exploratory study provides preliminary evidence for potential interrelations between various diagnostic measures of ankle function and structure in individuals with and without FAI. We found associations between MRI-results and selected measures of sensorimotor control, indicating a potential link between loss of ankle function and early joint degeneration. Despite these interrelations, each of the different assessment options appears to contain unique information on ankle functionality important in a clinical assessment. PMID:26309042

  20. Quantum steady computation

    International Nuclear Information System (INIS)

    This paper reports that current conceptions of quantum mechanical computers inherit from conventional digital machines two apparently interacting features, machine imperfection and temporal development of the computational process. On account of machine imperfection, the process would become ideally reversible only in the limiting case of zero speed. Therefore the process is irreversible in practice and cannot be considered to be a fundamental quantum one. By giving up classical features and using a linear, reversible and non-sequential representation of the computational process - not realizable in classical machines - the process can be identified with the mathematical form of a quantum steady state. This form of steady quantum computation would seem to have an important bearing on the notion of cognition

  1. Quantum steady computation

    Energy Technology Data Exchange (ETDEWEB)

    Castagnoli, G. (Dipt. di Informatica, Sistemistica, Telematica, Univ. di Genova, Viale Causa 13, 16145 Genova (IT))

    1991-08-10

    This paper reports that current conceptions of quantum mechanical computers inherit from conventional digital machines two apparently interacting features, machine imperfection and temporal development of the computational process. On account of machine imperfection, the process would become ideally reversible only in the limiting case of zero speed. Therefore the process is irreversible in practice and cannot be considered to be a fundamental quantum one. By giving up classical features and using a linear, reversible and non-sequential representation of the computational process - not realizable in classical machines - the process can be identified with the mathematical form of a quantum steady state. This form of steady quantum computation would seem to have an important bearing on the notion of cognition.

  2. A non-unity torque sharing function for torque ripple minimization of switched reluctance generators

    DEFF Research Database (Denmark)

    Park, Kiwoo; Liu, Xiao; Chen, Zhe

    2013-01-01

    This paper presents a new torque ripple minimization technique for a Switched Reluctance Generator (SRG). Although the SRG has many advantageous characteristics as a generator, it has not been widely employed in the industry. One of the most notorious disadvantages of the SRG is its high torque r...... ripple. In this paper, a non-unity Torque Sharing Function (TSF) is proposed to minimize the torque ripple over a wide speed range of operation. Simulation results are presented to verify the effectiveness of the proposed torque ripple minimization technique....

  3. A Systematic Review on the Treatment of Acute Ankle Sprain Brace versus Other Functional Treatment Types

    NARCIS (Netherlands)

    E. Kemler; I. van de Port; F. Backx; C.N. van Dijk

    2011-01-01

    Ankle injuries, especially ankle sprains, are a common problem in sports and medical care. Ankle sprains result in pain and absenteeism from work and/or sports participation, and can lead to physical restrictions such as ankle instability. Nowadays, treatment of ankle injury basically consists of ta

  4. Acute and chronic lateral ankle instability in the athlete.

    Science.gov (United States)

    Chan, Keith W; Ding, Bryan C; Mroczek, Kenneth J

    2011-01-01

    Ankle sprain injuries are the most common injury sustained during sporting activities. Three-quarters of ankle injuries involve the lateral ligamentous complex, comprised of the anterior talofibular ligament (ATFL), the calcaneofibular ligament (CFL), and the posterior talofibular ligament (PTFL). The most common mechanism of injury in lateral ankle sprains occurs with forced plantar flexion and inversion of the ankle as the body's center of gravity rolls over the ankle. The ATFL followed by the CFL are the most commonly injured ligaments. Eighty percent of acute ankle sprains make a full recovery with conservative management, while 20% of acute ankle sprains develop mechanical or functional instability, resulting in chronic ankle instability. Treatment of acute ankle sprains generally can be successfully managed with a short period of immobilization that is followed by functional rehabilitation. Patients with chronic ankle instability who fail functional rehabilitation are best treated with a Brostrom-Gould anatomic repair or, in those patients with poor tissue quality or undergoing revision surgery, an anatomic reconstruction. PMID:21332435

  5. Direct torque control for dual three-phase induction motor drives

    OpenAIRE

    Farina, Francesco; PROFUMO Francesco; Griva, Giovanni Battista; TENCONI Alberto; Bojoi, Iustin Radu

    2005-01-01

    A direct torque control (DTC) strategy for dual three-phase induction motor drives is discussed in this paper. The induction machine has two sets of stator three-phase windings spatially shifted by 30 electrical degrees. The DTC strategy is based on a predictive algorithm and is implemented in a synchronous reference frame aligned with the machine stator flux vector. The advantages of the discussed control strategy are constant inverter switching frequency, good transient and steady-state per...

  6. Torque maximisation of the PMAC motor for high performance, low inertia operation

    OpenAIRE

    Stewart, Paul

    2003-01-01

    This paper describes the techniques applied to maximise the torque en- velope of the permanent magnet AC (PMAC) motor operating under current and voltage constraints. Standard steady-state descriptions of the system are often suitable for control purposes when the rotor velocity is varying rela- tively slowly. In low inertia applications such as clutchless gearchange opera- tions, where in the pursuit of driveability, the motor is required to accelerate and decelerate its own rotor inertia as...

  7. Diabetic patients with and without peripheral neuropathy reveal different hip and ankle biomechanical strategies during stair descent

    Directory of Open Access Journals (Sweden)

    Andreja P. Picon

    2012-12-01

    Full Text Available BACKGROUND: The progression of diabetes and the challenge of daily tasks may result in changes in biomechanical strategies. Descending stairs is a common task that patients have to deal with, however it still has not been properly studied in this population. OBJECTIVES: We describe and compare the net joint moments and kinematics of the lower limbs in diabetic individuals with and without peripheral neuropathy and healthy controls during stair descent. METHOD: Forty-two adults were assessed: control group (13, diabetic group (14, and neuropathic diabetic group (15. The flexor and extensor net moment peaks and joint angles of the hip, knee, and ankle were described and compared in terms of effect size and ANOVAs (p<0.05. RESULTS: Both diabetic groups presented greater dorsiflexion [large effect size] and a smaller hip extensor moment [large effect size] in the weight acceptance phase. In the propulsion phase, diabetics with and without neuropathy showed a greater hip flexor moment [large effect size] and smaller ankle extension [large effect size]. CONCLUSION: Diabetic patients, even without neuropathy, revealed poor eccentric control in the weight acceptance phase, and in the propulsion phase, they showed a different hip strategy, where they chose to take the leg off the ground using more flexion torque at the hip instead of using a proper ankle extension function.

  8. Environmental Qualification of an Actuator Torque Switch

    International Nuclear Information System (INIS)

    Environmental qualification testing was performed on a modified Limitorque torque switch for the torque switch safety functions in the Limitorque type SMB actuators located inside and outside containment in a nuclear power plant. The torque switch specimen was installed in a Limitorque SMB-1 electric actuator mounted on an 8'' Velan gate valve and operated with a customized programmable logic controller to allow normal torque switch behaviour to be observed. The present paper describes the qualification testing performed. The modified torque switch was aged to a 30-year service life at the normal service conditions for both inside and outside containment. Aging included radiation, thermal and cycle aging. A seismic test and then a combined Loss of Coolant Accident (LOCA) and Main Steam Line Break (MSLB) steam accident simulation were followed. After each stage of aging, functional tests were done to confirm normal insulation resistance, normal contact resistance and normal operation. (authors)

  9. Estimating Torque Imparted on Spacecraft Using Telemetry

    Science.gov (United States)

    Lee, Allan Y.; Wang, Eric K.; Macala, Glenn A.

    2013-01-01

    There have been a number of missions with spacecraft flying by planetary moons with atmospheres; there will be future missions with similar flybys. When a spacecraft such as Cassini flies by a moon with an atmosphere, the spacecraft will experience an atmospheric torque. This torque could be used to determine the density of the atmosphere. This is because the relation between the atmospheric torque vector and the atmosphere density could be established analytically using the mass properties of the spacecraft, known drag coefficient of objects in free-molecular flow, and the spacecraft velocity relative to the moon. The density estimated in this way could be used to check results measured by science instruments. Since the proposed methodology could estimate disturbance torque as small as 0.02 N-m, it could also be used to estimate disturbance torque imparted on the spacecraft during high-altitude flybys.

  10. A very fast direct torque control for interior permanent magnet synchronous motors start up

    Energy Technology Data Exchange (ETDEWEB)

    Ghassemi, H.; Vaez-Zadeh, S. [University of Tehran (Iran). Faculty of Engineering

    2005-03-01

    Selection of the stator flux command in direct torque control (DTC) of permanent magnet synchronous motors is very important as it affects machine performance. For steady state operation, it can help to decrease the stator current or machine losses. However, in order to get a fast torque response during motor start up, one needs to change both the stator flux angle and magnitude. In this paper, a method is presented to find the optimal voltage vectors to change both the flux angle and its magnitude that results in high-speed dynamics for the torque response. The closed form formula given for the optimal voltage vector is derived based on maximizing the torque change in each sampling time. The simulation results show that the presented method is superior to the conventional DTC. In other words, it is shown that the voltage vectors derived from the switching table for conventional DTC are not the optimal voltage vectors for the situation in which there is a step change in the torque command. (author)

  11. Direct Torque Control for Three-Level Neutral Point Clamped Inverter-Fed Induction Motor Drive

    Directory of Open Access Journals (Sweden)

    M. K. Sahu

    2012-04-01

    Full Text Available Direct torque control (DTC is a control technique in AC drive systems to obtain high performance torque control. The classical DTC drive contains a pair of hysteresis comparators and suffers from variable switching frequency and high torque ripple. These problems can be solved by using space vector depending on the reference torque and flux. In this paper the space vector modulation technique is applied to the three-level Neutral Point Clamped (NPC inverter control in the proposed DTC-based induction motor drive system, resulting to a significant reduce of torque ripple. Three-level neutral point clamped inverters have been widely used in medium voltage applications. This type of inverters have several advantages over standard two-level VSI, such as greater number of levels in the output voltage waveforms, less harmonic distortion in voltage and current waveforms and lower switching frequencies. This paper emphasizes the derivation of switching states using the Space Vector Pulse Width Modulation (SVPWM technique. The control scheme is implemented using Matlab/Simulink. Experimental results using dSPACE validate the steady-state and the dynamic performance of the proposed control strategy.

  12. Direct Torque Control of Saturated Doubly-Fed Induction Generator using High Order Sliding Mode Controllers

    Directory of Open Access Journals (Sweden)

    Elhadj BOUNADJA

    2016-07-01

    Full Text Available The present work examines a direct torque control strategy using a high order sliding mode controllers of a doubly-fed induction generator (DFIG incorporated in a wind energy conversion system and working in saturated state. This research is carried out to reach two main objectives. Firstly, in order to introduce some accuracy for the calculation of DFIG performances, an accurate model considering magnetic saturation effect is developed. The second objective is to achieve a robust control of DFIG based wind turbine. For this purpose, a Direct Torque Control (DTC combined with a High Order Sliding Mode Control (HOSMC is applied to the DFIG rotor side converter. Conventionally, the direct torque control having hysteresis comparators possesses major flux and torque ripples at steady-state and moreover the switching frequency varies on a large range. The new DTC method gives a perfect decoupling between the flux and the torque. It also reduces ripples in these grandeurs. Finally, simulated results show, accurate dynamic performances, faster transient responses and more robust control are achieved.

  13. Predicting functional recovery after acute ankle sprain.

    Directory of Open Access Journals (Sweden)

    Sean R O'Connor

    Full Text Available INTRODUCTION: Ankle sprains are among the most common acute musculoskeletal conditions presenting to primary care. Their clinical course is variable but there are limited recommendations on prognostic factors. Our primary aim was to identify clinical predictors of short and medium term functional recovery after ankle sprain. METHODS: A secondary analysis of data from adult participants (N = 85 with an acute ankle sprain, enrolled in a randomized controlled trial was undertaken. The predictive value of variables (age, BMI, gender, injury mechanism, previous injury, weight-bearing status, medial joint line pain, pain during weight-bearing dorsiflexion and lateral hop test recorded at baseline and at 4 weeks post injury were investigated for their prognostic ability. Recovery was determined from measures of subjective ankle function at short (4 weeks and medium term (4 months follow ups. Multivariate stepwise linear regression analyses were undertaken to evaluate the association between the aforementioned variables and functional recovery. RESULTS: Greater age, greater injury grade and weight-bearing status at baseline were associated with lower function at 4 weeks post injury (p<0.01; adjusted R square=0.34. Greater age, weight-bearing status at baseline and non-inversion injury mechanisms were associated with lower function at 4 months (p<0.01; adjusted R square=0.20. Pain on medial palpation and pain on dorsiflexion at 4 weeks were the most valuable prognostic indicators of function at 4 months (p< 0.01; adjusted R square=0.49. CONCLUSION: The results of the present study provide further evidence that ankle sprains have a variable clinical course. Age, injury grade, mechanism and weight-bearing status at baseline provide some prognostic information for short and medium term recovery. Clinical assessment variables at 4 weeks were the strongest predictors of recovery, explaining 50% of the variance in ankle function at 4 months. Further

  14. Effects of Nintendo Wii Fit Plus training on ankle strength with functional ankle instability.

    Science.gov (United States)

    Kim, Ki-Jong; Jun, Hyun-Ju; Heo, Myoung

    2015-11-01

    [Purpose] The objective of this study was to examine the effects of a training program using the Nintendo Wii Fit Plus on the ankle muscle strengths of subjects with functional ankle instability. [Subjects and Methods] This study was conducted using subjects in their 20s who had functional ankle instability. They were randomized to a strengthening training group and a balance training group with 10 subjects in each, and they performed an exercise using Nintendo Wii Fit Plus for 20 minutes. In addition, every participant completed preparation and finishing exercises for 5 minutes, respectively. [Results] The muscle strengths after conducting plantar flexion and dorsiflexion significantly increased at the angular velocities of 60° and 120° in the strengthening training group. Furthermore, the muscle strengths after conducting plantar flexion, dorsiflexion, eversion, and inversion significantly increased at the angular velocities of 60° and 120° in the balance training group. [Conclusion] The balance training group using Nintendo Wii Fit Plus showed better results than the strengthening training group. Consequently, it is recommended to add the balance training program of the Nintendo Wii Fit Plus to conventional exercise programs to improve ankle muscle strength in functional ankle instability at a low cost. PMID:26696703

  15. MR arthrography of the ankle joint

    International Nuclear Information System (INIS)

    Due to its superior soft tissue contrast conventional MRI is the imaging method of choice in the evaluation of ankle joint disorders. Conventional MR imaging can accurately demonstrate normal or acutely injured ligaments; however, in subacute and chronic injury joint fluid necessary for delineation of injured ligaments is absent and MR arthrography should be performed. MR arthrography uses the intraarticular injection of contrast material to distend the joint, yielding improved discrimination of intraarticular structures. This joint distension with MR arthrography is also helpful in the staging of osteochondritis dissecans, since in cases of unstable lesions tracking of contrast material into the interface can be more easily demonstrated. Finally, high contrast and joint distension by MR arthrography improves the detection of intraarticular loose bodies, which often require surgery. MR artrography, although invasive, may provide additional information in various ankle joint disorders. (orig.)

  16. [Advances on biomechanics and kinematics of sprain of ankle joint].

    Science.gov (United States)

    Zhao, Yong; Wang, Gang

    2015-04-01

    Ankle sprains are orthopedic clinical common disease, accounting for joint ligament sprain of the first place. If treatment is not timely or appropriate, the joint pain and instability maybe develop, and even bone arthritis maybe develop. The mechanism of injury of ankle joint, anatomical basis has been fully study at present, and the diagnostic problem is very clear. Along with the development of science and technology, biological modeling and three-dimensional finite element, three-dimensional motion capture system,digital technology study, electromyographic signal study were used for the basic research of sprain of ankle. Biomechanical and kinematic study of ankle sprain has received adequate attention, combined with the mechanism research of ankle sprain,and to explore the the biomechanics and kinematics research progress of the sprain of ankle joint. PMID:26072625

  17. Diagnosis of ligament injuries in the superior ankle joint

    International Nuclear Information System (INIS)

    Nearly 40 years after ankle arthrography was first introduced, the anterior and inversion stress views of the ankle are still widely preferred as a noninvasive method of evaluating ligament injuries in the upper ankle. We consider the stress test, bilaterally performed using a standardized stress apparatus, as a basic examination by which to differentiate between slight and severe sprain. Intensive muscel splinting due to painful swelling can sometimes be treated by injection of local anesthetic. Like many authors, we perform ankle arthrography in cases where there is a significant difference between the clinical findings and the stress test. The technique of ankle arthrography can be readily learned and is extremely accurate in delineating the extent of ligamentous injury produced by moderate or severe ankle sprains. It can be performed in any X-ray department. (orig.)

  18. Diagnostic dilemmas in foot and ankle injuries

    Energy Technology Data Exchange (ETDEWEB)

    Keene, J.S.; Lange, R.H.

    1986-07-11

    Differential diagnosis of foot and ankle injuries should include (1) stress fractures of the great toe sesamoids, the shaft of the fifth metatarsal, and the tarsal navicular bone; (2) transchondral talar-dome fractures; (3) fractures of the os trigonum; and (4) dislocating peroneal tendons. Diagnosis of these injuries is challenging because the initial roentgenograms often are normal, and special clinical tests and ancillary studies are required.

  19. Osteoarthritis after osteosynthesis of ankle injuries

    International Nuclear Information System (INIS)

    98 patients were clinically and radiographically examined 2 to 9 years following the osteosynthesis of ankle fractures. The rate of secondary osteoarthritis was 70% including 40% of minor, 17% of medium and 13% of serious changes. Depending on the injured structures the frequency of posttraumatic osteoarthritis varies. Medium and serious radiology changes cause obvious dysfunction in 56% and 62% respectively. Joints free of Osteoarthritis one year after the injury will not develop secondary osteoarthritis later. (orig.)

  20. Diagnostic dilemmas in foot and ankle injuries

    International Nuclear Information System (INIS)

    Differential diagnosis of foot and ankle injuries should include (1) stress fractures of the great toe sesamoids, the shaft of the fifth metatarsal, and the tarsal navicular bone; (2) transchondral talar-dome fractures; (3) fractures of the os trigonum; and (4) dislocating peroneal tendons. Diagnosis of these injuries is challenging because the initial roentgenograms often are normal, and special clinical tests and ancillary studies are required

  1. Optimal management of ankle syndesmosis injuries

    OpenAIRE

    Porter DA; Jaggers RR; Barnes AF; Rund AM

    2014-01-01

    David A Porter, Ryan R Jaggers, Adam Fitzgerald Barnes, Angela M Rund Methodist Sports Medicine/The Orthopedic Specialists, Indianapolis, IN, USA Abstract: Syndesmosis injuries occur when there is a disruption of the distal attachment of the tibia and fibula. These injuries occur commonly (up to 18% of ankle sprains), and the incidence increases in the setting of athletic activity. Recognition of these injuries is key to preventing long-term morbidity. Diagnosis and treatment of these injuri...

  2. The management of soft tissue ankle injuries.

    OpenAIRE

    Crean, D.

    1981-01-01

    The anatomy of the ankle, and the types of sporting injuries that occur in this joint, are described. Traditional treatment of soft tissue injuries involves immobilisation, and the value of this is questioned. An alternative treatment strategy is described, and involves immobilisation and compression for twenty-four hours, followed by rapid mobilisation using a balance board. This alternative strategy can bring about full functional mobility in 94% of patients within 14 days.

  3. MR imaging of the ankle: Normal variants

    International Nuclear Information System (INIS)

    Thirty asymptomatic ankles were studied with high-resolution surface coil MR imaging. The thirty ankles were reviewed for identification or normal structures. The MR appearance of the deltoid and posterior to talo-fibular ligaments, peroneous brevis and longus tendons, and posterior aspect of the tibial-talar joint demonstrated several normal variants not previously described. These should not be misinterpreted as pathologic processes. The specific findings included (1) cortical irregularity of the posterior tibial-talar joint in 27 of 30 cases which should not be mistaken for osteonecrois; (2) normal posterior talo-fibular ligament with irregular and frayed inhomogeneity, which represents a normal variant in seven of ten cases; and (3) fluid in the shared peroneal tendons sheath which may be confused for a longitudinal tendon tear in three of 30 cases. Ankle imaging with the use of MR is still a relatively new procedure. Further investigation is needed to better define normal anatomy as well as normal variants. The authors described several structures that normally present with variable MR imaging appearances. This is clinically significant in order to maintain a high sensitivity and specificity in MR imaging interpretation

  4. Forces predicted at the ankle during running.

    Science.gov (United States)

    Burdett, R G

    1982-01-01

    A biomechanical model of the ankle joint was developed and was used to predict the forces at the ankle during the stance phase of running. Measurements from five cadavers were averaged to obtain insertion points and directions of pull of equivalent tendons with respect to the assumed center of the ankle joint. A minimum joint force solution was obtained by assuming that only two equivalent muscle groups could exert force at one time. Three subjects ran at 4.47 m/s across a force platform that recorded the external forces and moments acting on the foot. Cinematography was used to measure the foot and leg positions during stance. Peak resultant joint forces ranging from 9.0 to 13.3 times body weight and peak Achilles tendon forces ranging from 5.3 to 10.0 times body weight were predicted. Small variations in some cases resulted in large differences in predicted forces. The highest tendon forces predicted exceeded those reported to cause damage to cadaver tendons in other studies. PMID:7132650

  5. Kinesthesia Is Not Affected by Functional Ankle Instability Status.

    Science.gov (United States)

    Hubbard, Tricia J; Kaminski, Thomas W

    2002-12-01

    OBJECTIVE: To determine whether subjects with functional ankle instability suffered kinesthetic deficits in the injured ankle compared with the healthy ankle and to examine the effect of prophylactic ankle bracing on kinesthesia in uninjured and functionally unstable ankles. DESIGN AND SETTING: We tested subjects over 4 consecutive days in a climate-controlled athletic training/sports medicine laboratory setting. A single-group time-series design enabled all subjects to serve as their own controls. A different bracing condition was tested on each of those occasions. SUBJECTS: Sixteen subjects (8 men, 8 women; age = 21.6 +/- 1.7 years; mass = 73.5 +/- 15.0 kg; height = 172.9 +/- 8.8 cm) with unilateral functional ankle instability participated in this study. MEASUREMENTS: Kinesthetic threshold-to-detection of passive motion (TTDPM) measurements were obtained during passive inversion and eversion movements (0.5 degrees.s(-1)) under 4 different bracing or taping conditions (unbraced, Swede-O Ankle Lok, Aircast Air-Stirrup, and tape). RESULTS: We analyzed the data using a 3-factor analysis of variance with repeated measures on the ankle and motion factors. Threshold-to-detection of passive motion scores in the unbraced condition were significantly better than the TTDPM scores in any of the other 3 test conditions. No significant differences were seen in TTDPM scores between the 2 ankles under any of the 4 conditions. CONCLUSIONS: Threshold-to-detection of passive motion scores did not differ in uninjured ankles and those with functional instability; however, bracing with either the Ankle Lok or Air-Stirrup decreased the ability to detect passive motion when compared with the no-tape (unbraced) condition. Further research is needed to determine the exact contributions of taping and bracing on ankle joint kinesthesia. PMID:12937571

  6. Kinematics and kinetics of an accidental lateral ankle sprain

    OpenAIRE

    Kristianslund, Eirik; Bahr, Roald; Krosshaug, Tron

    2011-01-01

    Ankle sprains are common during sporting activities and can have serious consequences. Understanding of injury mechanisms is essential to prevent injuries, but only two previous studies have provided detailed descriptions of the kinematics of lateral ankle sprains and measures of kinetics are missing. In the present study a female handball player accidentally sprained her ankle during sidestep cutting in a motion analysis laboratory. Kinematics and kinetics were calculated from 240 Hz recordi...

  7. Alteration in global motor strategy following lateral ankle sprain

    OpenAIRE

    Bastien, Maude; Moffet, Hélène; Bouyer, Laurent J; Perron, Marc; Hébert, Luc J; Leblond, Jean

    2014-01-01

    Background Lateral ankle sprain (LAS) has often been considered an injury leading to localized joint impairments affecting the musculoskeletal system. Persistent chronic ankle instability and bilateral alterations in motor control after a first ankle sprain episode suggest that the origin of relapses might be a maladaptive reorganization of central motor commands. The objectives of this study were (1) to compare the quality of motor control through motor strategy variables of two groups (with...

  8. Experimental and computational analysis of composite ankle-foot orthosis

    OpenAIRE

    Dequan Zou, DSc; Tao He, MS; Michael Dailey, MBA, CO; Kirk E. Smith, BS; Matthew J. Silva, PhD; David R. Sinacore, PhD, PT; Michael J. Mueller, PhD, PT; Mary K. Hastings, DPT, MSCI

    2015-01-01

    Carbon fiber (CF) ankle-foot orthoses (AFOs) can improve gait by increasing ankle plantar-flexor power and improving plantar-flexor ankle joint moment and energy efficiency compared with posterior leaf spring AFOs made of thermoplastic. However, fabricating a CF AFO to optimize the performance of the individual user may require multiple AFOs and expensive fabrication costs. Finite element analysis (FEA) models were developed to predict the mechanical behavior of AFOs in this study. Three AFOs...

  9. Neuropathic midfoot deformity: associations with ankle and subtalar joint motion

    OpenAIRE

    Sinacore, David R; Gutekunst, David J; Hastings, Mary K.; Strube, Michael J; Bohnert, Kathryn L.; Prior, Fred W.; Johnson, Jeffrey E

    2013-01-01

    Background Neuropathic deformities impair foot and ankle joint mobility, often leading to abnormal stresses and impact forces. The purpose of our study was to determine differences in radiographic measures of hind foot alignment and ankle joint and subtalar joint motion in participants with and without neuropathic midfoot deformities and to determine the relationships between radiographic measures of hind foot alignment to ankle and subtalar joint motion in participants with and without neuro...

  10. Review of common and unusual causes of lateral ankle pain

    International Nuclear Information System (INIS)

    Lateral ankle pain is a common clinical presentation having several important causes, including lateral ligament injury, peroneal tendon injury, sinus tarsi syndrome, and nerve entrapments. However, other causes should be kept in mind in patients with unusual patterns of pain or intractable symptoms. We present a review of common and some unusual causes of lateral ankle pain including a review of post-operative imaging findings following surgery for lateral ankle ligament and peroneal tendon injuries. (orig.)

  11. Influence on ankle taping on dynamic balance performance

    OpenAIRE

    Kenny, Ian; Wu, Can; McEvoy, Johnson

    2011-01-01

    peer-reviewed This research aimed to investigate the effect of ankle taping on dynamic balance performance. Eighteen recreational athletes without any previous ankle sprain history performed six star excursion balance tests on each leg; randomly three trials with taped ankles and three trials without. A three-layer modified closed-basket inelastic taping technique was used. Normalised (by leg length) reaching distance was measured. It was found 1.Movement direction significantl...

  12. Review of ankle inversion sprain simulators in the biomechanics laboratory

    OpenAIRE

    Sophia Chui-Wai Ha; Daniel Tik-Pui Fong; Kai-Ming Chan

    2015-01-01

    Ankle inversion ligamentous sprain is one of the most common sports injuries. The most direct way is to investigate real injury incidents, but it is unethical and impossible to replicate on test participants. Simulators including tilt platforms, trapdoors, and fulcrum devices were designed to mimic ankle inversion movements in laboratories. Inversion angle was the only element considered in early designs; however, an ankle sprain is composed of inversion and plantarflexion in clinical observa...

  13. Understanding acute ankle ligamentous sprain injury in sports

    OpenAIRE

    Fong Daniel TP; Chan Yue-Yan; Mok Kam-Ming; Yung Patrick SH; Chan Kai-Ming

    2009-01-01

    Abstract This paper summarizes the current understanding on acute ankle sprain injury, which is the most common acute sport trauma, accounting for about 14% of all sport-related injuries. Among, 80% are ligamentous sprains caused by explosive inversion or supination. The injury motion often happens at the subtalar joint and tears the anterior talofibular ligament (ATFL) which possesses the lowest ultimate load among the lateral ligaments at the ankle. For extrinsic risk factors to ankle sprai...

  14. Systematic review of chronic ankle instability in children

    OpenAIRE

    Mandarakas, Melissa; Pourkazemi, Fereshteh; Sman, Amy; Burns, Joshua; Hiller, Claire E

    2014-01-01

    Background Chronic ankle instability (CAI) is a disabling condition often encountered after ankle injury. Three main components of CAI exist; perceived instability; mechanical instability (increased ankle ligament laxity); and recurrent sprain. Literature evaluating CAI has been heavily focused on adults, with little attention to CAI in children. Hence, the objective of this study was to systematically review the prevalence of CAI in children. Methods Studies were retrieved from major databas...

  15. The Anatomic Pattern of Injuries in Acute Inversion Ankle Sprains

    OpenAIRE

    Khor, Yuet Peng; Tan, Ken Jin

    2013-01-01

    Background: There are little data on the incidence and patterns of injuries seen on magnetic resonance imaging (MRI) in acute inversion ankle sprains. This study may help in the understanding of the pathomechanics, natural history, and outcomes of this common injury. Study Design: Case series; Level of evidence, 4. Methods: From June 2011 to June 2013, a total of 64 consecutive patients had MRI of the ankle performed for acute inversion injury to the ankle. All injuries/pathologies reported w...

  16. Neuromuscular control and rehabilitation of the unstable ankle

    OpenAIRE

    Hung, You-jou

    2015-01-01

    Lateral ankle sprain is a common orthopedic injury with a very high recurrence rate in athletes. After decades of research, it is still unclear what contributes to the high recurrence rate of ankle sprain, and what is the most effective intervention to reduce the incident of initial and recurrent injuries. In addition, clinicians often implement balance training as part of the rehabilitation protocol in hopes of enhancing the neuromuscular control and proprioception of the ankle joint. Howeve...

  17. Review of common and unusual causes of lateral ankle pain

    Energy Technology Data Exchange (ETDEWEB)

    Choudhary, Surabhi [Nuffield Orthopaedic Centre NHS Trust, Musculoskeletal Radiology, Oxford (United Kingdom); McNally, Eugene [Nuffield Orthopaedic Centre NHS Trust, Musculoskeletal Radiology, Oxford (United Kingdom); Nuffield Orthopaedic Centre and University of Oxford, Musculoskeletal Radiology, Oxford (United Kingdom)

    2011-11-15

    Lateral ankle pain is a common clinical presentation having several important causes, including lateral ligament injury, peroneal tendon injury, sinus tarsi syndrome, and nerve entrapments. However, other causes should be kept in mind in patients with unusual patterns of pain or intractable symptoms. We present a review of common and some unusual causes of lateral ankle pain including a review of post-operative imaging findings following surgery for lateral ankle ligament and peroneal tendon injuries. (orig.)

  18. Limiting the use of routine radiography for acute ankle injuries.

    OpenAIRE

    Cockshott, W P; Jenkin, J. K.; Pui, M.

    1983-01-01

    In the diagnosis of ankle injuries routine radiography is often productive. An international survey of the average number of radiographs made of injured ankles suggested that two projections are adequate to detect fractures. This was confirmed in a prospective study of 242 patients coming to a hospital emergency department with recent ankle injuries. All the fractures could be identified on an anteroposterior or a lateral projection, although some were more obvious on an oblique view. As well...

  19. Rehabilitation of Ankle and Foot Injuries in Athletes

    OpenAIRE

    Chinn, Lisa; Hertel, Jay

    2010-01-01

    Foot and ankle injuries are extremely common among athletes and other physically active individuals. Rehabilitation programs that emphasize the use of therapeutic exercise to restore joint range of motion, muscle strength, neuromuscular coordination, and gait mechanics have been shown to have clinical success for patients suffering various foot and ankle pathologies. Rehabilitation programs are discussed for ankle sprains, plantar fasciitis, Achilles tendonitis, and turf toe.

  20. Differences in Men's and Women's Mean Ankle Ligamentous Laxity

    OpenAIRE

    Wilkerson, Ricky D; Mason, Melanie A

    2000-01-01

    The incidence of ligamentous ankle injuries is known to be one of the most common athletic injuries that exists. Recently, there has been a great deal of interest regarding the increased risk of female ligamentous injury, such as the anterior cruciate ligament, lateral ankle sprains and others. The purpose of this study is to evaluate whether or not normal lateral ankle ligamentous laxity is similar in male and female athletes. This study selects 22 male and 27 female college athletes who hav...

  1. MRI in acute ligamentous injuries of the ankle.

    Science.gov (United States)

    Martella, Ilenia; Azzali, Emanuele; Milanese, Gianluca; Praticò, Francesco Emanuele; Ruggirello, Margherita; Trunfio, Vincenzo; Parziale, Raffaele; Corrado, Michele; Della Casa, Giovanni; Capasso, Raffaella; De Filippo, Massimo

    2016-01-01

    Ankle sprains are the most common lower limb injuries and affect more frequently young athletes; imaging is needed for an accurate diagnosis of such traumatic injuries. The purpose of this review is to analyse the magnetic resonance (MR) findings of both normal and pathological ankle's ligaments; indeed, MRI is the gold standard for the diagnosis of acute traumatic injuries and is useful for differentiation of the causes of ankle instability as well as for pre-operative planning. PMID:27467862

  2. Syndesmotic Malreduction after Ankle ORIF; Is Radiography Sufficient?

    OpenAIRE

    Alireza Manafi Rasi; Gholamhossein Kazemian; Mohamad M Omidian; Ali Nemati

    2013-01-01

      Background: Ankle fractures, especially those resulting from external rotation mechanisms are associated with injury to the distal tibiofibular syndesmosis. Some authors have recommended performing CT scanning after open ankle surgery to evaluate the reduction of syndesmosis. In this current study, we aimed to investigate the sensitivity of plain radiography in diagnosing syndesmosis malreduction after open reduction and internal fixation (ORIF) in patients with ankle fractures.   Methods: ...

  3. Experimental Implementation of Underactuated Potential Energy Shaping on a Powered Ankle-Foot Orthosis

    Science.gov (United States)

    Lv, Ge; Zhu, Hanqi; Elery, Toby; Li, Luwei; Gregg, Robert D.

    2016-01-01

    Traditional control methodologies of rehabilitation orthoses/exoskeletons aim at replicating normal kinematics and thus fall into the category of kinematic control. This control paradigm depends on pre-defined reference trajectories, which can be difficult to adjust between different locomotor tasks and human subjects. An alternative control category, kinetic control, enforces kinetic goals (e.g., torques or energy) instead of kinematic trajectories, which could provide a flexible learning environment for the user while freeing up therapists to make corrections. We propose that the theory of underactuated potential energy shaping, which falls into the category of kinetic control, could be used to generate virtual body-weight support for stroke gait rehabilitation. After deriving the nonlinear control law and simulating it on a human-like biped model, we implemented this controller on a powered ankle-foot orthosis that was designed specifically for testing torque control strategies. Experimental results with an able-bodied human subject demonstrate the feasibility of the control approach for both positive and negative virtual body-weight augmentation.

  4. Benign and malignant tumors of the foot and ankle

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Adam D.; Datir, Abhijit; Langley, Travis [Emory University Hospital, Department of Radiology, Section of Musculoskeletal Imaging, Atlanta, GA (United States); Tresley, Jonathan [University of Wisconsin, Department of Radiology, Madison, WI (United States); Clifford, Paul D.; Jose, Jean; Subhawong, Ty K. [University of Miami, Department of Radiology, Miami, FL (United States)

    2016-03-15

    Pain and focal masses in the foot and ankle are frequently encountered and often initiate a workup including imaging. It is important to differentiate benign lesions from aggressive benign or malignant lesions. In this review, multiple examples of osseous and soft tissue tumors of the foot and ankle will be presented. Additionally, the compartmental anatomy of the foot and ankle will be discussed in terms of its relevance for percutaneous biopsy planning and eventual surgery. Finally, a general overview of the surgical management of benign, benign aggressive and malignant tumors of the foot and ankle will be discussed. (orig.)

  5. [Measurement ofthe ankle-brachial pressure index (ABPI)].

    Science.gov (United States)

    Kulisić, Sandra Marinović

    2012-10-01

    Measurement of the ankle-brachial pressure index, also known as ankle-brachial index or ankle-arm index is a ratio of the ankle blood pressure and brachial blood pressure. It is easy to perform and allows for diagnosis and further definition of the severity of peripheral arterial disease with sensitivity 90% and specificity 98%. The test is not appropriate for mild arterial changes as in case of comorbidity. Its further objectives are to identify patients at an higher risk of cardiovascular events. PMID:23193828

  6. Benign and malignant tumors of the foot and ankle

    International Nuclear Information System (INIS)

    Pain and focal masses in the foot and ankle are frequently encountered and often initiate a workup including imaging. It is important to differentiate benign lesions from aggressive benign or malignant lesions. In this review, multiple examples of osseous and soft tissue tumors of the foot and ankle will be presented. Additionally, the compartmental anatomy of the foot and ankle will be discussed in terms of its relevance for percutaneous biopsy planning and eventual surgery. Finally, a general overview of the surgical management of benign, benign aggressive and malignant tumors of the foot and ankle will be discussed. (orig.)

  7. Torque-based gasoline engine control

    Energy Technology Data Exchange (ETDEWEB)

    Heintz, N.; Stier, G.; Beaumont, A.J.; Noble, A.D. [Ricardo, Shoreham-by-Sea (United Kingdom)

    2000-07-01

    This paper describes a new control strategy for gasoline engines that is based on engine torque. The reference for the calculation of the different actuator set points is a torque demand variable. This makes it possible to consider the influence on torque of both - manipulated variables inside the engine control system and signals belonging to external systems - at one central point. Therefore controlling the interaction between different components of electronic systems inside the vehicle is facilitated. This gives rise to new possibilities to extend the control strategy and to improve driveability. (author)

  8. Drag and Torque on Locked Screw Propeller

    Directory of Open Access Journals (Sweden)

    Tomasz Tabaczek

    2014-09-01

    Full Text Available Few data on drag and torque on locked propeller towed in water are available in literature. Those data refer to propellers of specific geometry (number of blades, blade area, pitch and skew of blades. The estimation of drag and torque of an arbitrary propeller considered in analysis of ship resistance or propulsion is laborious. The authors collected and reviewed test data available in the literature. Based on collected data there were developed the empirical formulae for estimation of hydrodynamic drag and torque acting on locked screw propeller. Supplementary CFD computations were carried out in order to prove the applicability of the formulae to modern moderately skewed screw propellers.

  9. Ankle mechanics during sidestep cutting implicates need for 2-degrees of freedom powered ankle-foot prostheses

    OpenAIRE

    Evandro M. Ficanha; Mohammad Rastgaar, PhD; Kenton R. Kaufman, PhD

    2015-01-01

    The ankle joint of currently available powered prostheses is capable of controlling one degree of freedom (DOF), focusing on improved mobility in the sagittal plane. To increase agility, the requirements of turning in prosthesis design need to be considered. Ankle kinematics and kinetics were studied during sidestep cutting and straight walking. There were no significant differences between the ankle sagittal plane mechanics when comparing sidestep cutting and straight walking; however, signi...

  10. Is End-Stage Ankle Arthrosis Best Managed with Total Ankle Replacement or Arthrodesis? A Systematic Review

    OpenAIRE

    Jordan, Robert W.; Chahal, Gurdip S.; Anna Chapman

    2014-01-01

    Introduction. End-stage ankle osteoarthritis is a debilitating condition. Traditionally, ankle arthrodesis (AA) has been the surgical intervention of choice but the emergence of total ankle replacement (TAR) has challenged this concept. This systematic review aims to address whether TAR or AA is optimal in terms of functional outcomes. Methods. We conducted a systematic review according to PRISMA checklist using the online databases Medline and EMBASE after January 1, 2005. Participants must ...

  11. Multi-objective optimization of a parallel ankle rehabilitation robot using modified differential evolution algorithm

    Science.gov (United States)

    Wang, Congzhe; Fang, Yuefa; Guo, Sheng

    2015-07-01

    Dimensional synthesis is one of the most difficult issues in the field of parallel robots with actuation redundancy. To deal with the optimal design of a redundantly actuated parallel robot used for ankle rehabilitation, a methodology of dimensional synthesis based on multi-objective optimization is presented. First, the dimensional synthesis of the redundant parallel robot is formulated as a nonlinear constrained multi-objective optimization problem. Then four objective functions, separately reflecting occupied space, input/output transmission and torque performances, and multi-criteria constraints, such as dimension, interference and kinematics, are defined. In consideration of the passive exercise of plantar/dorsiflexion requiring large output moment, a torque index is proposed. To cope with the actuation redundancy of the parallel robot, a new output transmission index is defined as well. The multi-objective optimization problem is solved by using a modified Differential Evolution(DE) algorithm, which is characterized by new selection and mutation strategies. Meanwhile, a special penalty method is presented to tackle the multi-criteria constraints. Finally, numerical experiments for different optimization algorithms are implemented. The computation results show that the proposed indices of output transmission and torque, and constraint handling are effective for the redundant parallel robot; the modified DE algorithm is superior to the other tested algorithms, in terms of the ability of global search and the number of non-dominated solutions. The proposed methodology of multi-objective optimization can be also applied to the dimensional synthesis of other redundantly actuated parallel robots only with rotational movements.

  12. Multi-objective Optimization of a Parallel Ankle Rehabilitation Robot Using Modified Differential Evolution Algorithm

    Institute of Scientific and Technical Information of China (English)

    WANG Congzhe; FANG Yuefa; GUO Sheng

    2015-01-01

    Dimensional synthesis is one of the most difficult issues in the field of parallel robots with actuation redundancy. To deal with the optimal design of a redundantly actuated parallel robot used for ankle rehabilitation, a methodology of dimensional synthesis based on multi-objective optimization is presented. First, the dimensional synthesis of the redundant parallel robot is formulated as a nonlinear constrained multi-objective optimization problem. Then four objective functions, separately reflecting occupied space, input/output transmission and torque performances, and multi-criteria constraints, such as dimension, interference and kinematics, are defined. In consideration of the passive exercise of plantar/dorsiflexion requiring large output moment, a torque index is proposed. To cope with the actuation redundancy of the parallel robot, a new output transmission index is defined as well. The multi-objective optimization problem is solved by using a modified Differential Evolution(DE) algorithm, which is characterized by new selection and mutation strategies. Meanwhile, a special penalty method is presented to tackle the multi-criteria constraints. Finally, numerical experiments for different optimization algorithms are implemented. The computation results show that the proposed indices of output transmission and torque, and constraint handling are effective for the redundant parallel robot; the modified DE algorithm is superior to the other tested algorithms, in terms of the ability of global search and the number of non-dominated solutions. The proposed methodology of multi-objective optimization can be also applied to the dimensional synthesis of other redundantly actuated parallel robots only with rotational movements.

  13. Steady State Dynamic Operating Behavior of Universal Motor

    Directory of Open Access Journals (Sweden)

    Muhammad Khan Burdi

    2015-01-01

    Full Text Available A detailed investigation of the universal motor is developed and used for various dynamic steady state and transient operating conditions of loads. In the investigation, output torque, motor speed, input current, input/output power and efficiency are computed, compared and analyzed for different loads. While this paper discusses the steady-state behavior of the universal motor, another companion paper, ?Transient dynamic behavior of universal motor?, will discuss its transient behavior in detail. A non-linear generalized electric machine model of the motor is considered for the analysis. This study was essential to investigate effect of output load on input current, power, speed and efficiency of the motor during operations. Previously such investigation is not known

  14. Direct torque control of brushless DC drives with reduced torque ripple

    OpenAIRE

    Liu, Y.; Zhu, Z Q; Howe, D

    2005-01-01

    The application of direct torque control (DTC) to brushless ac drives has been investigated extensively. This paper describes its application to brushless dc drives, and highlights the essential differences in its implementation, as regards torque estimation and the representation of the inverter voltage space vectors. Simulated and experimental results are presented, and it is shown that, compared with conventional current control, DTC results in reduced torque ripple and a faster dynamic re...

  15. Direct Torque Control of IPMSM to Improve Torque ripple and Efficiency based on Fuzzy Controller

    OpenAIRE

    B. Mirzaeian Dehkordi; H. Mostafavi; M. Ataie; M. Sadeghi Goghar

    2012-01-01

    In this paper, a stator-flux-reference frame control method is proposed in order to control the speed and torque of an Interior Permanent Magnet Synchronous Machine (IPMSM) in different loads condition. Direct Torque Control method (DTC) based on Space Vector Modulation (SVM) is used for control of IPMSM. In the proposed control method, conventional PI controller is used for controlling the stator flux, and torque of the motor. Also, a fuzzy controller is considered to improve the dynamic per...

  16. Brake assembly including torque monitor

    International Nuclear Information System (INIS)

    This patent describes a brake assembly for selectively braking rotation of an input shaft extending from a control rod drive having a longitudinal centerline axis, the shaft being rotatable for selectively inserting and withdrawing a control rod in a nuclear reactor vessel. It comprises a stationary base; an annular bearing mounted to the base; a brake mounted to the bearing; a backing plate mounted to the bearing; a first braking pad fixedly joined to the backing plate; a rotor disc fixedly connected to the input shaft and disposed adjacent to the first pad; a second braking pad disposed adjacent to the rotor disc; and means for selectively clamping the first and second pads against the rotor disc for braking the input shaft; means for torsionally restraining the brake including: a pin extending outwardly from the backing plate toward the base; and a spring extending from the base to the pin and generally perpendicular to the centerline axis; and means for monitoring the angle for monitoring braking torque capability of the brake

  17. Improved computed torque control for industrial robots

    Science.gov (United States)

    Uebel, Mark; Minis, Ioannis; Cleary, Kevin

    1992-01-01

    The authors examine the computed torque control problem for a robot arm with flexible, geared, joint drive systems which are typical in many industrial robots. The standard computed torque algorithm is not directly applicable to this class of manipulators due to the dynamics introduced by the joint drive systems. The proposed approach overcomes this problem by combining a novel computed torque algorithm with simple torque controllers at each joint of the robot. The control scheme is applied to a seven degree-of-freedom industrial manipulator, and the system performance in standard tasks is evaluated using both dynamic simulation and actual experiments. The results show that the proposed controller leads to improved tracking performance over a conventional PD (proportional plus derivative) controller.

  18. Sensorless vector and direct torque control

    CERN Document Server

    Vas, Peter

    1998-01-01

    This is the first comprehensive book on sensorless high performance a.c. drives. It is essential reading for anyone interested in acquiring a solid background on sensorless torque-controlled drives. It presents a detailed and unified treatment of sensorless vector-controlled and direct-torque controlled drive systems. It also discusses the applications of artificial intelligence to drives. Where possible, space vector theory is used and emphasis is laid on detailed mathematical and physical analysis. Sensorless drive schemes for different types of permanent magnet synchronous motors, synchronous reluctance motors, and induction motors are also presented. These include more than twenty vector drives e.g. five types of MRAS-based vector drives, and eleven types of direct-torque-controlled (DTC) drives, e.g. the ABB DTC drive. However, torque-controlled switched reluctance motor drives are also discussed due to their emerging importance. The book also covers various drive applications using artificial intellige...

  19. Torque Control of Friction Stir Welding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Longhurst Engineering, PLC and Vanderbilt University propose the innovation of torque control of friction stir welding (FSW) as a replacement to force control of...

  20. High Torque, Direct Drive Electric Motor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Bear Engineering proposes to develop an innovative high torque, low speed, direct drive motor in order to meet NASA's requirements for such devices. Fundamentally,...

  1. High Torque, Direct Drive Electric Motor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Bear Engineering proposes to advance the development of an innovative high torque, low speed, direct drive motor in order to meet NASA's requirements for such...

  2. AUTOMATIC CONTROL SYSTEM FOR TORQUE NATIONAL STANDARD

    OpenAIRE

    J. Galván-Mancilla; Torres-Guzmán, J C

    2004-01-01

    The continuous development of the technology and the increase of its complexity demand wider measurementintervals, a greater exactness and a greater diversity of the standards used in order to establish the units ormeasuring systems. Torque metrology is of great importance and a magnitude is of common use for industry,technical development and research. The realization, quantification and dissemination of this magnitude are tasksassigned to the Metrology National Center (CENAM) Torque Laborat...

  3. Mandibular lip bumper for molar torque control.

    Science.gov (United States)

    Celentano, Giuseppe; Longobardi, Annalisa; Cannavale, Rosangela; Perillo, Letizia

    2011-01-01

    Treatment effects of lip bumpers alone include flaring of the mandibular incisors, distalization and uprighting of the mandibular first molars, and buccal expansion of the canines, premolars, and molar. Lip forces are transmitted through this appliance onto the molars. Moreover the lip bumper is able to derotate, expand or constrict, upright and reinforce the anchorage whereas torque control is lacking. Aim of this paper is the presentation of a new type of lip bumper that allows the molar torque control. PMID:21515237

  4. Accretion torque on magnetized neutron stars

    OpenAIRE

    Dai, Hai-Lang; Li, Xiang-Dong

    2006-01-01

    The conventional picture of disk accretion onto magnetized neutron stars has been challenged by the spin changes observed in a few X-ray pulsars, and by theoretical results from numerical simulations of disk-magnetized star interactions. These indicate possible accretion during the propeller regime and the spin-down torque increasing with the accretion rate. Here we present a model for the accretion torque exerted by the disk on a magnetized neutron star, assuming accretion continues even for...

  5. Drag and Torque on Locked Screw Propeller

    OpenAIRE

    Tomasz Tabaczek; T. Bugalski

    2014-01-01

    Few data on drag and torque on locked propeller towed in water are available in literature. Those data refer to propellers of specific geometry (number of blades, blade area, pitch and skew of blades). The estimation of drag and torque of an arbitrary propeller considered in analysis of ship resistance or propulsion is laborious. The authors collected and reviewed test data available in the literature. Based on collected data there were developed the empirical formulae for estimation of hydro...

  6. Variable-Structure Direct Torque Control – A Class of Fast and Robust Controllers for Induction Machine Drives

    DEFF Research Database (Denmark)

    Lascu, Christian; Boldea, Ion; Blaabjerg, Frede

    2004-01-01

    A family of variable-structure controllers for induction machine drives is presented, in which the principles of direct torque control (DTC), variable-structure control (VSC) and space-vector pulsewidth modulation are combined to ensure high-performance operation, both in the steady state and under...... transient conditions. Three new VSC schemes are designed following the DTC voltage-control-based philosophy. These provide robust, fast and accurate torque and flux control, without the penalty of high chattering. Comparative results demonstrate that proposed techniques preserve the DTC transient merits...

  7. A reactive torque control law for gyroscopically controlled space vehicles

    Science.gov (United States)

    Farmer, J. E.

    1973-01-01

    A method of control is developed based on the reactive torques as seen by the individual CMG gimbals. The application of a torque to the gimbal of a CMG rotates the momentum vector and applies a torque to the spacecraft according to well-known laws. The response (rotation) of the vehicle produces a reverse or reaction torque opposing the torque producing the gimbal movement. The reactive torque and the pseudoinverse control schemes are contrasted in order to point out the simplicity of the first method. Simulation was performed only to the extent necessary to prove that reactive torque stabilization and control is feasible.

  8. High Performance of Space Vector Modulation Direct Torque Control SVM-DTC Based on Amplitude Voltage and Stator Flux Angle

    Directory of Open Access Journals (Sweden)

    Hassan Farhan Rashag

    2013-04-01

    Full Text Available Various aspects related to controlling induction motor are investigated. Direct torque control is an original high performance control strategy in the field of AC drive. In this proposed method, the control system is based on Space Vector Modulation (SVM, amplitude of voltage in direct- quadrature reference frame (d-q reference and angle of stator flux. Amplitude of stator voltage is controlled by PI torque and PI flux controller. The stator flux angle is adjusted by rotor angular frequency and slip angular frequency. Then, the reference torque and the estimated torque is applied to the input of PI torque controller and the control quadrature axis voltage is determined. The control d-axis voltage is determined from the flux calculator. These q and d axis voltage are converted into amplitude voltage. By applying polar to Cartesian on amplitude voltage and stator flux angle, direct voltage and quadratures voltage are generated. The reference stator voltages in d-q are calculated based on forcing the stator voltage error to zero at next sampling period. By applying inverse park transformation on d-q voltages, the stator voltages in &alpha and &beta frame are generated and apply to SVM. From the output of SVM, the motor control signal is generated and the speed of the induction motor regulated toward the rated speed. The simulation Results have demonstrated exceptional performance in steady and transient states and shows that decrease of torque and flux ripples is achieved in a complete speed range.

  9. Extraneous torque and compensation control on the electric load simulator

    Science.gov (United States)

    Jiao, Zongxia; Li, Chenggong; Ren, Zhiting

    2003-09-01

    In this paper a novel motor-drive load simulator based on compensation control strategy is proposed and designed. Through analyzing the torque control system consisting of DC torque motor, PWM module and torque sensor, it is shown that performance of the motor-drive load simulator is possible to be as good as that of the electro-hydraulic load simulator in the range of small torque. In the course of loading, the rotation of the actuator would cause a strong disturbance torque through the motor back-EMF, which produces extraneous torque similar as in electro-hydraulic load simulator. This paper analyzes the cause of extraneous torque inside the torque motor in detail and presents an appropriate compensation control with which the extraneous torque can be compensated and the good performance of the torque control system can be obtained. The results of simulation indicate that the compensation is very effective and the track performance is according with the request.

  10. Knudsen torque on heated micro beams

    International Nuclear Information System (INIS)

    Thermally induced mechanical loading has been shown to have significant effects on micro/nano objects immersed in a gas with a non-uniform temperature field. While the majority of existing studies and related applications focus on forces, we investigate the torque, and thus the rotational motion, produced by such a mechanism. Using the asymptotic analysis in the near continuum regime, the Knudsen torque acting on an asymmetrically located uniformly heated microbeam in a cold enclosure is investigated. The existence of a non-zero net torque is demonstrated. In addition, it has been found that by manipulating the system configuration, the rotational direction of the torque can be changed. Two types of rotational motion of the microbeam have been identified: the pendulum motion of a rectangular beam, and the unidirectional rotation of a cylindrical beam. A rotational frequency of 4 rpm can be achieved for the cylindrical beam with a diameter of 3μm at Kn = 0.005. Illustrated by the simulations using the direct simulation of Monte Carlo, the Knudsen torque can be much increased in the transition regime, demonstrating the potential of Knudsen torque serving as a rotation engine for micro/nano objects

  11. Maximum voluntary joint torque as a function of joint angle and angular velocity: model development and application to the lower limb.

    Science.gov (United States)

    Anderson, Dennis E; Madigan, Michael L; Nussbaum, Maury A

    2007-01-01

    Measurements of human strength can be important during analyses of physical activities. Such measurements have often taken the form of the maximum voluntary torque at a single joint angle and angular velocity. However, the available strength varies substantially with joint position and velocity. When examining dynamic activities, strength measurements should account for these variations. A model is presented of maximum voluntary joint torque as a function of joint angle and angular velocity. The model is based on well-known physiological relationships between muscle force and length and between muscle force and velocity and was tested by fitting it to maximum voluntary joint torque data from six different exertions in the lower limb. Isometric, concentric and eccentric maximum voluntary contractions were collected during hip extension, hip flexion, knee extension, knee flexion, ankle plantar flexion and dorsiflexion. Model parameters are reported for each of these exertion directions by gender and age group. This model provides an efficient method by which strength variations with joint angle and angular velocity may be incorporated into comparisons between joint torques calculated by inverse dynamics and the maximum available joint torques. PMID:17485097

  12. Direct Torque Control of Matrix Converter Fed Induction Motor Drive

    OpenAIRE

    JAGADEESAN Karpagam; NIRMAL Kumar; MUTHUSAMY Suresh

    2011-01-01

    This paper presents the Direct TorqueControl (DTC) of induction motor drive using matrixconverters. DTC is a high performance motor controlscheme with fast torque and flux responses. However,the main disadvantage of conventional DTC iselectromagnetic torque ripple. In this paper, directtorque control for Induction Motors using MatrixConverters is analysed and points out the problem ofthe electromagnetic torque ripple which is one of themost important drawbacks of the Direct TorqueControl. Bes...

  13. Kinematics of ankle taping after a training session.

    Science.gov (United States)

    Meana, M; Alegre, L M; Elvira, J L L; Aguado, X

    2008-01-01

    This study aimed to test the effectiveness of ankle taping on the limitation of forced supination during a change of direction, as well as the losses of effectiveness after a 30-minute training session. Fifteen young men with no ankle injury volunteered for the study. The static and dynamic ranges of movement (ROM) were measured before and after a training session. The dynamic measurements were recorded using high-speed 3D photogrammetry. The differences between static and dynamic measures of ankle supination and plantar flexion were significant. The losses of effectiveness during supination and ankle plantar flexion restriction were 42.3 % and 47.6 %, respectively. Ankle taping was effective in restricting the maximal static ROMs before a training session, but the effectiveness decreased after 30 min of training. The present study shows the necessity of performing dynamic ROM analysis of sports techniques involved in the ankle sprain mechanism in order to determine the degree of tape restriction after a training session, because there were differences between static and dynamic ankle ROMs. The lack of effects on the restriction of the dynamic plantar flexion would bring into question the necessity of ankle taping in subjects without previous injuries. PMID:17614032

  14. Relationship between stress ankle radiographs and injured ligaments on MRI

    International Nuclear Information System (INIS)

    This study was performed to investigate the relationship between the injured lateral ankle ligaments on MRI and stress ankle radiographs. Two hundred and twenty-nine consecutive patients (mean age 35.5 years, SD 14.6 years; 136 males and 93 females) that underwent ankle stress radiographs and MRI for lateral ankle instability were included. Tibiotalar tilt angle and anterior translation of talus were measured on stress ankle radiographs. Degree of lateral ligaments (anterior talofibular, calcaneofibular, and posterior talofibular) and deltoid ligament injuries were evaluated and scored as intact (0), partial injury (1), and complete injury (2) on MR images. Effusion of ankle joint was also recorded. The effects of gender, age, injuries of ligaments, and ankle joint effusion on stress radiographs were statistically analyzed. Gender (p = 0.010), age (p = 0.020), and anterior talofibular ligament (ATFL) injury (p < 0.001) were the factors significantly affecting tibiotalar tilt angle. Posterior talofibular ligament (PTFL) injury (p = 0.014) was found to be the only significant factor affecting the anterior translation on the anterior drawer radiographs. ATFL injury and PTFL injury on MRI significantly affected tibiotalar tilt angle and anterior drawer on stress radiographs. Other factors, such as age and gender, need to be considered in evaluating radiographic lateral ankle instability. (orig.)

  15. Magnetic resonance imaging findings in anterolateral impingement of the ankle

    International Nuclear Information System (INIS)

    Objective. To demonstrate the MR imaging findings of anterolateral impingement (ALI) of the ankle.Design and patients. Nine patients with a history of ankle inversion injury and chronic lateral ankle pain were imaged with MR imaging, and the findings correlated with the results of arthroscopy. Three additional patients with clinically suspected ALI of the ankle were also included. Ankle MR imaging studies from 20 control patients in whom ALI was not suspected clinically were examined for similar findings to the patient group.Results. MR imaging findings in the patients with ALI included a soft tissue signal mass in the anterolateral gutter of the ankle in 12 of 12 (100%) cases, corresponding to the synovial hypertrophy and soft tissue mass found at arthroscopy in the nine patients who underwent arthroscopy. Disruption, attenuation, or marked thickening of the anterior talofibular ligament was seen in all cases. Additional findings included signs of synovial hypertrophy elsewhere in the tibiotalar joint in seven of 12 patients (58%) and bony and cartilaginous injuries to the tibiotalar joint in five of 12 (42%). None of the control patients demonstrated MR imaging evidence of a soft tissue mass in the anterolateral gutter.Conclusions. ALI of the ankle is a common cause for chronic lateral ankle pain. It has been well described in the orthopedic literature but its imaging findings have not been clearly elucidated. The MR imaging findings, along with the appropriate clinical history, can be used to direct arthroscopic examination and subsequent debridement. (orig.)

  16. Rehabilitation of the Ankle After Acute Sprain or Chronic Instability

    OpenAIRE

    Mattacola, Carl G.; Dwyer, Maureen K.

    2002-01-01

    Objective: To outline rehabilitation concepts that are applicable to acute and chronic injury of the ankle, to provide evidence for current techniques used in the rehabilitation of the ankle, and to describe a functional rehabilitation program that progresses from basic to advanced, while taking into consideration empirical data from the literature and clinical practice.

  17. THE EFFECTS OF KINESIO TAPING ON PROPRIOCEPTION AT THE ANKLE

    Directory of Open Access Journals (Sweden)

    Mark DeBeliso

    2004-03-01

    Full Text Available An experiment was designed to determine if KinesioTM taping the anterior and lateral portion of the ankle would enhance ankle proprioception compared to the untaped ankle. 30 subjects, 15 men, 15 women, ages 18-30 participated in this study. Exclusion criteria: Ankle injury < 6 months prior to testing, significant ligament laxity as determined through clinical evaluation by an ATC, or any severe foot abnormality. Experiment utilized a single group, pretest and posttest. Plantar flexion and inversion with 20° of plantar flexion reproduction of joint position sense (RJPS was determined using an ankle RJPS apparatus. Subjects were barefooted, blindfolded, and equipped with headphones playing white noise to eliminate auditory cues. Subjects had five trials in both plantar flexion and inversion with 20° plantar flexion before and after application of the KinesioTM tape to the anterior/lateral portion of the ankle. Constant error and absolute error were determined from the difference between the target angle and the trial angle produced by the subject. The treatment group (KinesioTM taped subjects showed no change in constant and absolute error for ankle RJPS in plantar flexion and 20º of plantar flexion with inversion when compared to the untaped results using the same motions. The application of KinesioTM tape does not appear to enhance proprioception (in terms of RJPS in healthy individuals as determined by our measures of RJPS at the ankle in the motions of plantar flexion and 20º of plantar flexion with inversion.

  18. Relationship between stress ankle radiographs and injured ligaments on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyoung Min; Chung, Chin Youb; Chung, Myung Ki; Won, Sung Hun; Lee, Seung Yeol; Park, Moon Seok [Seoul National University Bundang Hospital, Department of Orthopaedic Surgery, Kyungki (Korea, Republic of); Kwon, Soon-Sun [Seoul National University Bundang Hospital, Biomedical Research Institute, Kyungki (Korea, Republic of)

    2013-11-15

    This study was performed to investigate the relationship between the injured lateral ankle ligaments on MRI and stress ankle radiographs. Two hundred and twenty-nine consecutive patients (mean age 35.5 years, SD 14.6 years; 136 males and 93 females) that underwent ankle stress radiographs and MRI for lateral ankle instability were included. Tibiotalar tilt angle and anterior translation of talus were measured on stress ankle radiographs. Degree of lateral ligaments (anterior talofibular, calcaneofibular, and posterior talofibular) and deltoid ligament injuries were evaluated and scored as intact (0), partial injury (1), and complete injury (2) on MR images. Effusion of ankle joint was also recorded. The effects of gender, age, injuries of ligaments, and ankle joint effusion on stress radiographs were statistically analyzed. Gender (p = 0.010), age (p = 0.020), and anterior talofibular ligament (ATFL) injury (p < 0.001) were the factors significantly affecting tibiotalar tilt angle. Posterior talofibular ligament (PTFL) injury (p = 0.014) was found to be the only significant factor affecting the anterior translation on the anterior drawer radiographs. ATFL injury and PTFL injury on MRI significantly affected tibiotalar tilt angle and anterior drawer on stress radiographs. Other factors, such as age and gender, need to be considered in evaluating radiographic lateral ankle instability. (orig.)

  19. Magnetic resonance imaging findings in anterolateral impingement of the ankle

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, L.K. III.; Cooperman, A.E. [Department of Radiology, Duke University Medical Center, Durham, NC (United States); Helms, C.A. [Department of Radiology, Duke University Medical Center, Durham, NC (United States); Duke University Medical Center, Durham, NC (United States); Speer, K.P. [Division of Orthopaedic Surgery, Duke University Medical Center, Durham, NC (United States)

    2000-01-01

    Objective. To demonstrate the MR imaging findings of anterolateral impingement (ALI) of the ankle.Design and patients. Nine patients with a history of ankle inversion injury and chronic lateral ankle pain were imaged with MR imaging, and the findings correlated with the results of arthroscopy. Three additional patients with clinically suspected ALI of the ankle were also included. Ankle MR imaging studies from 20 control patients in whom ALI was not suspected clinically were examined for similar findings to the patient group.Results. MR imaging findings in the patients with ALI included a soft tissue signal mass in the anterolateral gutter of the ankle in 12 of 12 (100%) cases, corresponding to the synovial hypertrophy and soft tissue mass found at arthroscopy in the nine patients who underwent arthroscopy. Disruption, attenuation, or marked thickening of the anterior talofibular ligament was seen in all cases. Additional findings included signs of synovial hypertrophy elsewhere in the tibiotalar joint in seven of 12 patients (58%) and bony and cartilaginous injuries to the tibiotalar joint in five of 12 (42%). None of the control patients demonstrated MR imaging evidence of a soft tissue mass in the anterolateral gutter.Conclusions. ALI of the ankle is a common cause for chronic lateral ankle pain. It has been well described in the orthopedic literature but its imaging findings have not been clearly elucidated. The MR imaging findings, along with the appropriate clinical history, can be used to direct arthroscopic examination and subsequent debridement. (orig.)

  20. Foot and ankle injuries in child and adolescent athletes

    OpenAIRE

    Yildirim, Yakup; Esemenli, Tanil

    2004-01-01

    Foot and ankle injuries are most commonly encountered in athletes. Of these, pediatric and adolescent injuries have unique characteristics because of the distinct growth potentials and their consequences specific to this age group. In this article, foot and ankle injuries in child and adolescent athletes are reviewed in the light of the literature.

  1. Rehabilitation of the Ankle after Acute Sprain or Chronic Instability.

    Science.gov (United States)

    Mattacola, Carl G.; Dwyer, Maureen K.

    2002-01-01

    Outlines rehabilitation concepts applicable to acute and chronic ankle injury, providing evidence for current techniques used in ankle rehabilitation and describing a functional rehabilitation program that progresses from basic to advanced, while taking into account empirical data from the literature and clinical practice. The article notes that…

  2. Triplane ankle fracture with deltoid ligament tear and syndesmotic disruption

    OpenAIRE

    Cummings, Robert Jay

    2008-01-01

    In patients with immature skeletons, ligamentous injuries rarely accompany ankle fractures. In this article, we report about deltoid ligament tears and syndesmotic disruptions accompanying triplane ankle fractures in two children, and make recommendations as to the evaluation and treatment of children with such injuries.

  3. Acute lateral ankle sprains: from functional treatment to prevention

    NARCIS (Netherlands)

    Kemler, H.J.

    2015-01-01

    Ankle sprains are common in daily life and often considered to be minor injuries. The objective in this thesis was to provide more evidence on the burden and optimal management of ankle sprains in terms of the magnitude of the problem, the prognostic consequences and ways to improve treatment and p

  4. Clinical experiences with three different designs of ankle prostheses.

    Science.gov (United States)

    Rippstein, Pascal F

    2002-12-01

    Until 1995, fusion was in our institution the only rational surgical option for a severe ankle arthrosis. Consistent reports about good mid- and long-term results with ankle replacement allowed us to change our minds. Ankle replacement became the gold standard and fusion was then almost totally banished. Because ankle arthrosis can be morphologically different from one patient to another, we soon believed that one single type of ankle prosthesis would not be the universal optimal solution for all patients. We therefore divided the ankle arthrosis into three groups. Each group shows the best solution from each of the ankle prostheses with which we had gained experience (Agility, STAR, and BP). The Agility prosthesis, which was indicated for ankles with extremely damaged geometry, did not restore sufficiently the ankle motion. Preoperatively stiff ankles remained stiff postoperatively. Additionally, significant residual pain was more likely to occur in those patients. These cases did not show significant advantages compared with ankle fusion, especially from a functional point of view. Fusion for these stiff ankles is therefore today our first treatment of choice. In our experience, the malleolar joints do not have to be replaced. Even a severe arthrosis at this level does not produce significant pain, provided that osteophytes have been removed and joint height has been restored by the implanted prosthesis. It is our strong belief that these malleolar joints are also less sensitive to pain, similar to the femoropatellar joint. For these reasons, a replacement of the malleolar joints and the resurfacing of the talar sides is not necessary. Leaving the talar sides untouched requires less bone resection and makes the implantation of the talar component easier. Although we obtained good results with the STAR prosthesis, we progressively abandoned it because of these reasons, and we preferred the BP prosthesis. The BP prosthesis works on the same biomechanic principle as

  5. Robotic Ankle for Omnidirectional Rock Anchors

    Science.gov (United States)

    Parness, Aaron; Frost, Matthew; Thatte, Nitish

    2013-01-01

    Future robotic exploration of near-Earth asteroids and the vertical and inverted rock walls of lava caves and cliff faces on Mars and other planetary bodies would require a method of gripping their rocky surfaces to allow mobility without gravitational assistance. In order to successfully navigate this terrain and drill for samples, the grippers must be able to produce anchoring forces in excess of 100 N. Additionally, the grippers must be able to support the inertial forces of a moving robot, as well gravitational forces for demonstrations on Earth. One possible solution would be to use microspine arrays to anchor to rock surfaces and provide the necessary load-bearing abilities for robotic exploration of asteroids. Microspine arrays comprise dozens of small steel hooks supported on individual suspensions. When these arrays are dragged along a rock surface, the steel hooks engage with asperities and holes on the surface. The suspensions allow for individual hooks to engage with asperities while the remaining hooks continue to drag along the surface. This ensures that the maximum possible number of hooks engage with the surface, thereby increasing the load-bearing abilities of the gripper. Using the microspine array grippers described above as the end-effectors of a robot would allow it to traverse terrain previously unreachable by traditional wheeled robots. Furthermore, microspine-gripping robots that can perch on cliffs or rocky walls could enable a new class of persistent surveillance devices for military applications. In order to interface these microspine grippers with a legged robot, an ankle is needed that can robotically actuate the gripper, as well as allow it to conform to the large-scale irregularities in the rock. The anchor serves three main purposes: deploy and release the anchor, conform to roughness or misalignment with the surface, and cancel out any moments about the anchor that could cause unintentional detachment. The ankle design contains a

  6. Clinical assessment and management of ankle sprains.

    Science.gov (United States)

    Myrick, Karen M

    2014-01-01

    Ankle sprains are a common occurrence and are frequently either undertreated or overtreated. With the incidence estimated at more than 3 million a year and at a rate of 2.15/1,000 in the United States alone, this is an orthopaedic injury that providers should be acutely aware of and successfully able to evaluate and treat. This clinical feature will provide a thorough review of the mechanism of injury, the history and physical examination, and the classification and management of these injuries. Clinical red flags are discussed. PMID:25233201

  7. MRI of injuries of the lateral ankle ligaments

    International Nuclear Information System (INIS)

    The most frequent sport injury of the ankle is located in the lateral ankle ligaments. The diagnosis of lateral collateral ankle ligament trauma is based on patient history, clinical examination, and stress radiography, allowing a fair diagnosis for the daily routine. For the direct visualization and precise diagnosis of the lateral ankle ligaments MRI provides the best answer. MRI is used with controlled positioning of the foot, correct angulation of sequenzes, and distinct analysis of MR findings. Sinus tarsi ligaments and ligaments of the distal syndesmosis should be included to the report. In selected patients MRI allows the best evaluation of the extent of the lateral ankle ligaments. MRI is the method of choice for combined osteochondral injuries and soft tissue lesions too. (orig.)

  8. Syndesmosis and lateral ankle sprains in the National Football League.

    Science.gov (United States)

    Osbahr, Daryl C; Drakos, Mark C; O'Loughlin, Padhraig F; Lyman, Stephen; Barnes, Ronnie P; Kennedy, John G; Warren, Russell F

    2013-11-01

    Syndesmosis sprains in the National Football League (NFL) can be a persistent source of disability, especially compared with lateral ankle injuries. This study evaluated syndesmosis and lateral ankle sprains in NFL players to allow for better identification and management of these injuries. Syndesmosis and lateral ankle sprains from a single NFL team database were reviewed over a 15-year period, and 32 NFL team physicians completed a questionnaire detailing their management approach. A comparative analysis was performed analyzing several variables, including diagnosis, treatment methods, and time lost from sports participation. Thirty-six syndesmosis and 53 lateral ankle sprains occurred in the cohort of NFL players. The injury mechanism typically resulted from direct impact in the syndesmosis and torsion in the lateral ankle sprain group (P=.034). All players were managed nonoperatively. The mean time lost from participation was 15.4 days in the syndesmosis and 6.5 days in the lateral ankle sprain groups (P⩽.001). National Football League team physicians varied treatment for syndesmosis sprains depending on the category of diastasis but recommended nonoperative management for lateral ankle sprains. Syndesmosis sprains in the NFL can be a source of significant disability compared with lateral ankle sprains. Successful return to play with nonoperative management is frequently achieved for syndesmosis and lateral ankle sprains depending on injury severity. With modern treatment algorithms for syndesmosis sprains, more aggressive nonoperative treatment is advocated. Although the current study shows that syndesmosis injuries require longer rehabilitation periods when compared with lateral ankle sprains, the time lost from participation may not be as prolonged as previously reported. PMID:24200441

  9. Standard practice for calibration of torque-measuring instruments for verifying the torque indication of torque testing machines

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This practice is to specify procedure for the calibration of elastic torque-measuring instruments. Note 1—Verification by deadweight and a lever arm is an acceptable method of verifying the torque indication of a torque testing machine. Tolerances for weights used are tabulated in Practice WK6364; methods for calibration of the weights are given in NIST Technical Note 577, Methods of Calibrating Weights for Piston Gages. 1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.3 This practice is intended for the calibration of static or quasi-static torque measuring instruments. The practice is not applicable for high speed torque calibrations or measurements. 1.4 This standard does not purport to address all of the safety concerns, if any,...

  10. Comparing Arc-shaped Feet and Rigid Ankles with Flat Feet and Compliant Ankles for a Dynamic Walker

    DEFF Research Database (Denmark)

    Kuhlemann, Ilyas; Matthias Braun, Jan; Wörgötter, Florentin;

    2014-01-01

    In this paper we show that exchanging curved feet and rigid ankles by at feet and compliant ankles improves the range of gait parameters for a bipedal dynamic walker. The new lower legs were designed such that they t to the old set-up, allowing for a direct and quantitative comparison. The dynami...

  11. Using torque switch settings and spring pack characteristics to determine actuator output torques

    International Nuclear Information System (INIS)

    Actuator output torque of motor operated valves is often a performance parameter of interest. It is not always possible to directly measure this torque. Torque spring pack deflection directly reflects actuator output torque and can be directly measured on most actuators. The torque spring pack may be removed from the actuator and tested to determine its unique force-deflection relationship. Or, a representative force-deflection relationship for the particular spring pack model may be available. With either relationship, measurements of torque spring pack deflection may then be correlated to corresponding forces. If the effective length of the moment arm within the actuator is known, actuator output torque can then be determined. The output torque is simply the product of the effective moment arm length and the spring pack force. This paper presents the reliability of this technique as indicated by testing. TU Electric is evaluating this technique for potential use in the future. Results presented in this paper should be considered preliminary. Applicability of these results may be limited to actuators and their components in a condition similar to those for which test data have been examined

  12. A Method to Accurately Estimate the Muscular Torques of Human Wearing Exoskeletons by Torque Sensors

    Directory of Open Access Journals (Sweden)

    Beomsoo Hwang

    2015-04-01

    Full Text Available In exoskeletal robots, the quantification of the user’s muscular effort is important to recognize the user’s motion intentions and evaluate motor abilities. In this paper, we attempt to estimate users’ muscular efforts accurately using joint torque sensor which contains the measurements of dynamic effect of human body such as the inertial, Coriolis, and gravitational torques as well as torque by active muscular effort. It is important to extract the dynamic effects of the user’s limb accurately from the measured torque. The user’s limb dynamics are formulated and a convenient method of identifying user-specific parameters is suggested for estimating the user’s muscular torque in robotic exoskeletons. Experiments were carried out on a wheelchair-integrated lower limb exoskeleton, EXOwheel, which was equipped with torque sensors in the hip and knee joints. The proposed methods were evaluated by 10 healthy participants during body weight-supported gait training. The experimental results show that the torque sensors are to estimate the muscular torque accurately in cases of relaxed and activated muscle conditions.

  13. Fracture line index of fibular stalk and the ankle joint bone in the classification of the ankle joint trauma

    International Nuclear Information System (INIS)

    Objective: To evaluate the fracture line index of fibular stalk and the ankle joint bone in the classification of the ankle joint trauma. Methods: Measure fracture line index of fibular stalk and the ankle joint in 217 adult cases of fracture and dislocation of ankle joint. And the cases were classified by the results of the measurement. Results: Measurement was unavailable in 9 cases of tearing fracture. In 31 cases, the lesions could not be particularly classified. And in the rest 176 cases the trauma were precisely classified. The over all successful rate was 81.6%. Conclusion: Fracture line index of fibular stalk and the ankle joint bone are valuable in classification of the trauma of the angle joint. While the specificity of this method is low in differentiating the adducting and abducting fracture of the medial angle, in which a combined investigation is recommended

  14. Improved Torque Control Performance of Direct Torque Control for 5-Phase Induction Machine

    Directory of Open Access Journals (Sweden)

    Logan Raj Lourdes Victor Raj

    2013-12-01

    Full Text Available In this paper, the control of five-phase induction machine using Direct Torque Control (DTC is presented. The general D-Q model of five-phase induction machine is discussed. The de-coupled control of stator flux and electromagnetic torque based on hysteresis controller similar to conventional DTC is applied to maintain the simplicity of the system. Three sets of look-up tables consist of voltage vectors with different amplitude that selects the  most optimal voltage vectors according motor operation condition is proposed. This provides excellent torque dynamic control, reduces torque ripple, lower switching frequency (high efficiency and extension of constant torque. Simulation results validate the improvement achieved.

  15. Design, Implementation and Evaluation of a Torque Transducer with Ability of Real-time Torque Monitoring

    Directory of Open Access Journals (Sweden)

    A Zeinali

    2016-04-01

    Full Text Available Torque, speed, and power as mechanical variables are associated with the functional performance of any rotating machinery. The real-time performance and the efficiency of a machine can be determined with on-line measurement of these parameters. In this investigation a rotary torque meter (transducer was constructed from strain gauge sensors for measuring the torque of rotating shafts. The system converts the torque of rotating shaft into voltage signals, based on the principle of strain gauge resistance. The signals are then amplified and converted into digital signals. These digital signals are sent to a RF receiver circuit for displaying and storage. Results of static calibration and a series of dynamic tests confirmed a satisfactory operation of the designed apparatus in various conditions. Also, the torque measuring range, resolution and the accuracy were from 3 to 700 N m, 3 N m and 1%, respectively.

  16. The foot and ankle of Australopithecus sediba.

    Science.gov (United States)

    Zipfel, Bernhard; DeSilva, Jeremy M; Kidd, Robert S; Carlson, Kristian J; Churchill, Steven E; Berger, Lee R

    2011-09-01

    A well-preserved and articulated partial foot and ankle of Australopithecus sediba, including an associated complete adult distal tibia, talus, and calcaneus, have been discovered at the Malapa site, South Africa, and reported in direct association with the female paratype Malapa Hominin 2. These fossils reveal a mosaic of primitive and derived features that are distinct from those seen in other hominins. The ankle (talocrural) joint is mostly humanlike in form and inferred function, and there is some evidence for a humanlike arch and Achilles tendon. However, Au. sediba is apelike in possessing a more gracile calcaneal body and a more robust medial malleolus than expected. These observations suggest, if present models of foot function are correct, that Au. sediba may have practiced a unique form of bipedalism and some degree of arboreality. Given the combination of features in the Au. sediba foot, as well as comparisons between Au. sediba and older hominins, homoplasy is implied in the acquisition of bipedal adaptations in the hominin foot. PMID:21903807

  17. Coherent control of spin torque dynamics

    International Nuclear Information System (INIS)

    We study time resolved precessional magnetization dynamics induced by spin momentum transfer in nanopillars of CoFeB/MgO/CoFeB magnetic tunnelling junctions (MTJ). Spin transfer torque precession of the CoFeB free layer is excited by ultra short current pulses (0.1 to 5 ns duration) with current densities around 106 A/cm2. The time resolved precession of the free layer is studied by measuring the time resolved magneto resistance change of the MTJ using a fast sampling oscilloscope. Our setup allows both to detect the spin torque precession during the current pulse and the magnetization ringing after pulse termination. From the decay of the precession we can derive the effective Gilbert damping parameter of the MTJ free layer. We show that by adapting the duration of the excitation pulse to integer multiples of the period of the spin torque precession the magnetization ringing can be coherently suppressed. Such coherent control of spin torque dynamics is a prerequisite for ultra fast ballistic spin transfer torque magnetization reversal

  18. Torque equilibrium attitude control for Skylab reentry

    Science.gov (United States)

    Glaese, J. R.; Kennel, H. F.

    1980-01-01

    The method of torque equilibrium attitude control used to control the reentry of Skylab to an altitude below 150 km without the use of thruster fuel once the attitude was established is discussed. The Skylab attitude and pointing control system, which included rate gyros, sun sensors, star tracker, the Apollo telescope mount digital computer, control moment gyros and cold-gas attitude thrusters, is presented. The 12 torque equilibrium attitudes found at which aerodynamic, gravity gradient and gyroscopic torques would balance are indicated, and the three of those at which the solar power supply would be adequate for attitude control are illustrated. The equilibrium seeking method employed is then examined, and the operation and performance of the torque equilibrium attitude control system during the three weeks prior to Skylab reentry are discussed. It is concluded that the torque equilibrium attitude control method developed for Skylab was successful in performing its assigned mission, and will be valuable for the design of future, low-altitude spacecraft or tethered vehicles.

  19. Coherent control of spin torque dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, Hans Werner; Serrano-Guisan, Santiago [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany); Rott, Karsten; Reiss, Guenter [University of Bielefeld, Universitaetsstr. 25, D-33615 Bielefeld (Germany); Langer, Juergen; Ocker, Berthold [Singulus Nano Deposition Technologies GmbH, Hanauer Landstr. 103, 63796 Kahl am Main (Germany)

    2008-07-01

    We study time resolved precessional magnetization dynamics induced by spin momentum transfer in nanopillars of CoFeB/MgO/CoFeB magnetic tunnelling junctions (MTJ). Spin transfer torque precession of the CoFeB free layer is excited by ultra short current pulses (0.1 to 5 ns duration) with current densities around 10{sup 6} A/cm2. The time resolved precession of the free layer is studied by measuring the time resolved magneto resistance change of the MTJ using a fast sampling oscilloscope. Our setup allows both to detect the spin torque precession during the current pulse and the magnetization ringing after pulse termination. From the decay of the precession we can derive the effective Gilbert damping parameter of the MTJ free layer. We show that by adapting the duration of the excitation pulse to integer multiples of the period of the spin torque precession the magnetization ringing can be coherently suppressed. Such coherent control of spin torque dynamics is a prerequisite for ultra fast ballistic spin transfer torque magnetization reversal.

  20. Imaging evaluation of traumatic ligamentous injuries of the ankle and foot.

    Science.gov (United States)

    Nazarenko, Anna; Beltran, Luis S; Bencardino, Jenny T

    2013-05-01

    Sports ankle injuries are very common worldwide. In the United States, it is estimated that 2 million acute ankle sprains occur each year, averaging to $318 to $914 per sprain. Magnetic resonance imaging is excellent for depicting normal ankle anatomy and can elegantly demonstrate ligamentous injuries of the ankle and associated conditions after ankle sprain. This article encompasses epidemiology, biomechanics, normal anatomy, and pathologic conditions of the ankle and foot ligaments. The specific ligaments discussed include the syndesmotic ligaments, lateral ligament complex of the ankle, deltoid ligament, spring ligament, ligaments of the sinus tarsi, and the Lisfranc ligament. PMID:23622094

  1. Early intra-articular complement activation in ankle fractures

    DEFF Research Database (Denmark)

    Schmal, Hagen; Salzmann, Gian M; Niemeyer, Philipp;

    2014-01-01

    Cytokine regulation possibly influences long term outcome following ankle fractures, but little is known about synovial fracture biochemistry. Eight patients with an ankle dislocation fracture were included in a prospective case series and matched with patients suffering from grade 2 osteochondri......Cytokine regulation possibly influences long term outcome following ankle fractures, but little is known about synovial fracture biochemistry. Eight patients with an ankle dislocation fracture were included in a prospective case series and matched with patients suffering from grade 2...... osteochondritis dissecans (OCD) of the ankle. All fractures needed external fixation during which joint effusions were collected. Fluid analysis was done by ELISA measuring aggrecan, bFGF, IL-1 β, IGF-1, and the complement components C3a, C5a, and C5b-9. The time periods between occurrence of fracture and...... and OCD patients, bFGF, IGF-1, and all complement components were significantly higher concentrated in ankle joints with fractures (P < 0.01). Complement activation and inflammatory cell infiltration characterize the joint biology following acute ankle fractures....

  2. Managing ankle ligament sprains and tears: current opinion.

    Science.gov (United States)

    McGovern, Ryan P; Martin, RobRoy L

    2016-01-01

    The purpose of this paper is to present a current review of pathoanatomical features, differential diagnosis, objective assessment, intervention, and clinical course associated with managing lateral ankle ligament sprains. Proper diagnosis and identification of affected structures should be obtained through history and objective assessment. From this information, an individualized evidence-based intervention plan can be developed to enable recovery while decreasing the risk of reinjury. An appropriate evaluation is needed not only to determine the correct diagnosis but also to allow for grading and determining the prognosis of the injury in those with an acute lateral ankle sprain. Examination should include an assessment of impairments as well as a measure of activity and participation. Evidence-based interventions for those with an acute lateral ankle sprain should include weight bearing with bracing, manual therapy, progressive therapeutic exercises, and cryotherapy. For those with chronic ankle instability (CAI), interventions should include manual therapy and a comprehensive rehabilitation program. It is essential to understand the normal clinical course for athletes who sustain a lateral ankle sprain as well as risk factors for an acute injury and CAI. Risk factors for both an acute lateral ankle sprain and CAI include not using an external support and not participating in an appropriate exercise program. Incorporating the latest evidence-based rehabilitation techniques provides the best course of treatment for athletes with an acute ankle sprain or CAI. PMID:27042147

  3. Rear wheel torque vectoring model predictive control with velocity regulation for electric vehicles

    Science.gov (United States)

    Siampis, Efstathios; Velenis, Efstathios; Longo, Stefano

    2015-11-01

    In this paper we propose a constrained optimal control architecture for combined velocity, yaw and sideslip regulation for stabilisation of the vehicle near the limit of lateral acceleration using the rear axle electric torque vectoring configuration of an electric vehicle. A nonlinear vehicle and tyre model are used to find reference steady-state cornering conditions and design two model predictive control (MPC) strategies of different levels of fidelity: one that uses a linearised version of the full vehicle model with the rear wheels' torques as the input, and another one that neglects the wheel dynamics and uses the rear wheels' slips as the input instead. After analysing the relative trade-offs between performance and computational effort, we compare the two MPC strategies against each other and against an unconstrained optimal control strategy in Simulink and Carsim environment.

  4. AUTOMATIC CONTROL SYSTEM FOR TORQUE NATIONAL STANDARD

    Directory of Open Access Journals (Sweden)

    J. Galván-Mancilla

    2004-04-01

    Full Text Available The continuous development of the technology and the increase of its complexity demand wider measurementintervals, a greater exactness and a greater diversity of the standards used in order to establish the units ormeasuring systems. Torque metrology is of great importance and a magnitude is of common use for industry,technical development and research. The realization, quantification and dissemination of this magnitude are tasksassigned to the Metrology National Center (CENAM Torque Laboratory, in Mexico.For the dissemination of this magnitude the Torque National Standard relies on a system, which, in its originaldesign, was operated manually originating high consumption of man-hours in the development of a calibration.This work presents the standard automation and the benefits of the automatic control system.

  5. Casimir Torque in Inhomogeneous Dielectric Plates

    CERN Document Server

    Long, William

    2013-01-01

    In this work, we consider a torque caused by the well known quantum mechanical Casimir effect arising from quantized field fluctuations between plates with inhomogeneous, sharply discontinuous, dielectric properties. While the Casimir effect is a relatively well understood phenomenon, systems resulting in lateral or rotational forces are far less developed; to our knowledge, a theoretical study of discontinuous dielectric variants of such systems has not been attempted. We utilize a Proximity Force Approximation in conjunction with the Lifshitz dielectric formula to perform theoretical analyses of resultant torques in systems with bisected and quadrisected dielectric regions. We also develop a high precision Monte Carlo type numerical integrator to approximate our derived expressions. Our calculations of an energy density linear with the alignment angle result in a constant torque and have implications in NEMS (nano electromechanical systems) and MEMS (micro electromechanical systems), including a postulated ...

  6. Torque for an Inertial Piezoelectric Rotary Motor

    Directory of Open Access Journals (Sweden)

    Jichun Xing

    2013-01-01

    Full Text Available For a novel inertial piezoelectric rotary motor, the equation of the strain energy in the piezoceramic bimorph and the equations of the strain energy and the kinetic energy in the rotor are given. Based on them, the dynamic equation of the motor is obtained. Using these equations, the inertial driving torque of the motor is investigated. The results show that the impulsive driving torque changes with changing peak voltage of the excitation signal, the piezoelectric stress constant, the thickness of the piezoceramic bimorph, and the rotor radius obviously. Tests about the motor torque are completed which verifies the theory analysis here in. The results can be used to design the operating performance of the motor.

  7. Fundamental Limits of Optical Force and Torque

    CERN Document Server

    Rahimzadegan, Aso; Fernandez-Corbaton, Ivan; Rockstuhl, Carsten

    2016-01-01

    Optical force and torque provide unprecedented control on the spatial motion of small particles. A valid scientific question, that has many practical implications, concerns the existence of fundamental upper bounds for the achievable force and torque exerted by a plane wave illumination with a given intensity. Here, while studying isotropic particles, we show that different light-matter interaction channels contribute to the exerted force and torque and analytically derive upper bounds for each of the contributions. Specific examples for particles that achieve those upper bounds are provided. We study how and to which extent different contributions can be made to add up. Our insights are important for applications ranging from molecular sorting, particle manipulation, nanorobotics up to ambitious projects such as laser-propelled spaceships.

  8. How Successful are Current Ankle Replacements?: A Systematic Review of the Literature

    OpenAIRE

    Gougoulias, Nikolaos; Khanna, Anil; Maffulli, Nicola

    2009-01-01

    Total ankle arthroplasty provides an alternative to arthrodesis for management of ankle arthritis. What is the outcome of total ankle arthroplasty implants currently in use? We conducted a systematic literature search of studies reporting on the outcome of total ankle arthroplasty. We included peer-reviewed studies reporting on at least 20 total ankle arthroplasties with currently used implants, with a minimum followup of 2 years. The Coleman Methodology Score was used to evaluate the quality...

  9. Isokinetic testing of evertor and invertor muscles in patients with chronic ankle instability.

    OpenAIRE

    David, Pascal; Halimi, Mohamad; Mora, Isabelle; Doutrellot, Pierre-Louis; Petitjean, Michel

    2013-01-01

    Ankle sprains are among the most common sport-related injuries and can lead to chronic ankle instability. Impaired sensorimotor function of the ankle musculature is often suggested as a cause. The current study sought to assess and compare the isokinetic performance and electromyographic patterns of evertor and invertor muscles in patients with chronic ankle instability and in a control group. Twelve patients with chronic ankle instability and twelve healthy subjects were included. Isokinetic...

  10. Biochemical T2* MR quantification of ankle arthrosis in pes cavovarus

    OpenAIRE

    Krause, F G; Klammer, G; Benneker, L M; Werlen, S; Mamisch, T.C.; Weber, M.

    2010-01-01

    Pes cavovarus affects the ankle biomechanics and may lead to ankle arthrosis. Quantitative T2 STAR (T2*) magnetic resonance (MR) mapping allows high resolution of thin cartilage layers and quantitative grading of cartilage degeneration. Detection of ankle arthrosis using T2* mapping in cavovarus feet was evaluated. Eleven cavovarus patients with symptomatic ankle arthrosis (13 feet, mean age 55.6 years, group 1), 10 cavovarus patients with no or asymptomatic, mild ankle arthrosis (12 feet, me...

  11. Biomechanics of supination ankle sprain : a case report of an accidental injury event in the laboratory

    OpenAIRE

    Fong, Daniel Tik-Pui; Hong, Youlian; Shima, Yosuke; Krosshaug, Tron; Young, Patrick Shu-Hang; Chan, Kai-Ming

    2009-01-01

    Ankle sprain is the most common injury in sports,5 but the mechanism of injury is not clear. Injury mechanisms can be studied through many different approaches.9 Over the years, ankle kinematics has been studied during simulated subinjury or close-to-injury situations, that is, sudden simulated ankle spraining motion on inversion platforms.11 Because these tests did not induce real injury, they could only somewhat suggest the ankle kinematics during an ankle sprain injury. The most direct way...

  12. Effect of a 6-week dynamic neuromuscular training programme on ankle joint function: A Case report

    OpenAIRE

    O'Driscoll Jeremiah; Kerin Fearghal; Delahunt Eamonn

    2011-01-01

    Abstract Background Ankle joint sprain and the subsequent development of chronic ankle instability (CAI) are commonly encountered by clinicians involved in the treatment and rehabilitation of musculoskeletal injuries. It has recently been advocated that ankle joint post-sprain rehabilitation protocols should incorporate dynamic neuromuscular training to enhance ankle joint sensorimotor capabilities. To date no studies have reported on the effects of dynamic neuromuscular training on ankle joi...

  13. Electroacupuncture reduces the evoked responses of the spinal dorsal horn neurons in ankle-sprained rats

    OpenAIRE

    Kim, Jae Hyo; Kim, Hee Young; Chung, Kyungsoon; Chung, Jin Mo

    2011-01-01

    Acupuncture is shown to be effective in producing analgesia in ankle sprain pain in humans and animals. To examine the underlying mechanisms of the acupuncture-induced analgesia, the effects of electroacupuncture (EA) on weight-bearing forces (WBR) of the affected foot and dorsal horn neuron activities were examined in a rat model of ankle sprain. Ankle sprain was induced manually by overextending ligaments of the left ankle in the rat. Dorsal horn neuron responses to ankle movements or compr...

  14. Clinician Recommendations and Perceptions of Factors Associated With Ankle Brace Use

    OpenAIRE

    Denton, Jason M.; Waldhelm, Andrew; Hacke, Jonathon D.; Gross, Michael T.

    2015-01-01

    Background: Little information is available regarding the ankle braces orthopaedic sports medicine clinicians recommend or clinicians’ concerns that may influence their decisions to recommend use of an ankle brace. Hypotheses: (1) Clinicians most frequently recommend lace-up braces with straps. (2) Clinicians who are concerned about potential adverse side effects from ankle brace use are less likely to recommend an ankle brace to prevent ankle sprain injuries. Study Design: Descriptive survey...

  15. Responses of spinal dorsal horn neurons to foot movements in rats with a sprained ankle

    OpenAIRE

    Kim, Jae Hyo; Kim, Hee Young; Chung, Kyungsoon; Chung, Jin Mo

    2011-01-01

    Acute ankle injuries are common problems and often lead to persistent pain. To investigate the underlying mechanism of ankle sprain pain, the response properties of spinal dorsal horn neurons were examined after ankle sprain. Acute ankle sprain was induced manually by overextending the ankle of a rat hindlimb in a direction of plantarflexion and inversion. The weight-bearing ratio (WBR) of the affected foot was used as an indicator of pain. Single unit activities of dorsal horn neurons in res...

  16. Ultrasound-guided interventions of the foot and ankle.

    Science.gov (United States)

    Yablon, Corrie M

    2013-02-01

    Ultrasound (US) provides excellent delineation of tendons and ligaments in the foot and ankle and provides real-time visualization of a needle during interventions, yielding greater accuracy and efficacy than the traditional blind approach using anatomical landmarks. For this reason, US is rapidly gaining acceptance as the preferred modality for guiding interventions in the foot and ankle where the anatomy is complex, neurovascular structures should be identified, and precise technique is demanded. In the foot and ankle, US is especially useful to guide tendon sheath, bursal, and Achilles paratenon injections, Morton neuroma injections, plantar fascial injections, and joint aspirations and injections. PMID:23487336

  17. Ankle-foot orthosis function in low-level myelomeningocele.

    Science.gov (United States)

    Hullin, M G; Robb, J E; Loudon, I R

    1992-01-01

    Six children with low-level myelomeningocele underwent gait analysis. All showed excessive ankle dorsiflexion and knee flexion when walking barefoot. A rigid thermoplastic ankle-foot orthosis (AFO) improved gait by preventing ankle dorsiflexion and reducing knee flexion. Biomechanically, the AFO caused a reduction in external knee moment by aligning the knee with the ground reaction force. Small changes in the foot-shank angle of the orthosis had profound effects on knee mechanics. Knee hyperextension could be controlled by a rocker sole. Kinetic gait analysis permits understanding of the biomechanical effects of orthoses. PMID:1613099

  18. Proprioceptive exercises for ankle ligament injury: a CAT

    Directory of Open Access Journals (Sweden)

    Raúl Aguilera Eguía

    2013-06-01

    Full Text Available This CAT (Critically Appraised Topic answered the question: In recreational athletes suffering from chronic ankle sprain, can proprioceptive exercises reduce its recurrence?The clinical question was analyzed in three parts: patient, intervention and outcome. The purpose was to test the validity, results and effectiveness of proprioceptive exercises in recreational athletes suffering from chronic ankle sprain to reduce its recurrence from the article "Effectiveness of proprioceptive exercises for ankle ligament injury in adults: A systematic literature and meta-analisys "Postle”1 (2012.

  19. Review of ankle inversion sprain simulators in the biomechanics laboratory

    Directory of Open Access Journals (Sweden)

    Sophia Chui-Wai Ha

    2015-10-01

    Full Text Available Ankle inversion ligamentous sprain is one of the most common sports injuries. The most direct way is to investigate real injury incidents, but it is unethical and impossible to replicate on test participants. Simulators including tilt platforms, trapdoors, and fulcrum devices were designed to mimic ankle inversion movements in laboratories. Inversion angle was the only element considered in early designs; however, an ankle sprain is composed of inversion and plantarflexion in clinical observations. Inversion velocity is another parameter that increased the reality of simulation. This review summarised the simulators, and aimed to compare and contrast their features and settings.

  20. Return to Play Following Ankle Sprain and Lateral Ligament Reconstruction.

    Science.gov (United States)

    Shawen, Scott B; Dworak, Theodora; Anderson, Robert B

    2016-10-01

    Ankle sprains are the most common musculoskeletal injury occurring during athletics. Proper initial treatment with supportive pain control, limited immobilization, early return to weight bearing and range of motion, and directed physical therapy are essential for preventing recurrent injury. Reconstruction of the lateral ligaments is indicated for patients with continued instability and dysfunction despite physical therapy. Return to athletic activity should be reserved for athletes who have regained strength, proprioception, and range of motion of the injured ankle. Athletes with a history of an ankle sprain should be prophylactically braced or tapped to reduce risk of recurrent injury. PMID:27543408

  1. Multicenter follow-up study of ankle fracture surgery

    Institute of Scientific and Technical Information of China (English)

    XU Hai-lin; WANG Gang; WANG Guang-lin; WU Xin-bao; LIU Li-min; LI Xuan; ZHANG Dian-ying; FU Zhong-guo; WANG Tian-bing; ZHANG Pei-xun; JIANG Bao-guo; SHEN Hui-liang

    2012-01-01

    Background Few data on ankle fractures in China from large multicenter epidemiological and clinical studies are available.The aim of this research was to evaluate the epidemiological features and surgical outcomes of ankle fractures by reviewing 235 patients who underwent ankle fracture surgery at five hospitals in China.Methods This study included patients who underwent ankle fracture surgery at five Chinese hospitals from January 2000 to July 2009.Age,gender,mechanism of injury,Arbeitsgemeinschaft für Osteosynthesefragen (AO) fracture type,fracture pattern,length of hospital stay and treatment outcome were recorded.Statistical analyses were conducted using SPSS software.The American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot scale,visual analogue scale (VAS),and arthritis scale were used to evaluate outcome.Results Of 235 patients with ankle fractures,105 were male with an average age of 37.8 years and 130 were female with an average age of 47.3 years.The average follow-up period was 55.7 months.There were significant differences in the ratios of patients in different age groups between males and females,and in mechanisms of injury among different age groups.There were also significant differences in the length of hospital stay among different fracture types and mechanisms of injury.In healed fractures,the average AOFAS ankle-hindfoot score was 95.5,with an excellence rate of 99.6%,the average VAS score was 0.17,and the average arthritis score was 0.18.Movement of the injured ankle was significantly different to that of the uninjured ankle.There were no significant differences between AO fracture types,fracture patterns or follow-up periods and AOFAS score,but there were some significant differences between these parameters and ankle joint movements,pain VAS score and arthritis score.Conclusions Ankle fractures occur most commonly in middle-aged and young males aged 20-39 years and in elderly females aged 50-69 years.The most common mechanisms of

  2. Diffusion of torqued active Brownian particles

    Science.gov (United States)

    Sevilla, Francisco J.

    An analytical approach is used to study the diffusion of active Brownian particles that move at constant speed in three-dimensional space, under the influence of passive (external) and active (internal) torques. The Smoluchowski equation for the position distribution of the particles is obtained from the Kramer-Fokker-Planck equation corresponding to Langevin equations for active Brownian particles subject to torques. In addition of giving explicit formulas for the mean square-displacement, the non-Gaussian behavior is analyzed through the kurtosis of the position distribution that exhibits an oscillatory behavior in the short-time limit. FJS acknowledges support from PAPIIT-UNAM through the grant IN113114

  3. Implementing Torque Control with High-Ratio Gear Boxes and without Joint-Torque Sensors

    OpenAIRE

    Del Prete, Andrea; Mansard, Nicolas; Ramos Ponce, Oscar Efrain; Stasse, Olivier; Nori, Francesco

    2015-01-01

    This paper presents a complete framework (estimation, identification and control) for the implementation of joint-torque control on the humanoid robot HRP-2. While torque control has already been implemented on a few humanoid robots, this is one of the first implementations of torque control on a robot that was originally built to be position controlled (iCub[1] and Asimo[2] being the first two, to the best of our knowledge). The challenge comes from both the hardware, which does not include ...

  4. The role of interaction torque and muscle torque in the control of downward squatting

    OpenAIRE

    Fujisawa, Hiroyuki; Suzuki, Hiroto; Murakami, Kenichi; Kawakami, Shingo; Suzuki, Makoto

    2016-01-01

    [Purpose] The purposes of this study were first to analyze the multijoint dynamics of downward squatting, and to examine the contribution of interaction torque and muscle torque to net torque, and second, to examine mechanisms of movement control. [Subjects] The subjects were 31 healthy men with a mean age of 21.0 ± 1.2 years (range, 19–24 years). [Methods] Squatting tasks with the trunk in two positions, an erect and anterior tilt position, were performed by the subjects. Net, interaction, m...

  5. [Ankle fractures in the elderly patient].

    Science.gov (United States)

    Crevoisier, Xavier; Baalbaki, Rayan; Dos Santos, Tiago; Assal, Mathieu

    2014-12-17

    Ankle fractures in adults are usually managed by open reduction internal fixation. In elderly patients the surgical dilemma relates to bone quality. Osteoporosis is the enemy of internal fixation, and secure purchase of screws in osteopenic bone may be difficult to achieve. Insufficient screw purchase may lead to loss of reduction, wound breakdown, and infection. Postoperative management after osteosynthesis usually requires an extended period of restricted weight bearing. However, this is not feasible in older patients as a result of their lack of strength in the upper extremities and frequent comorbidities. Therefore, augmen- ted methods of internal fixation and specific surgical techniques have been developed using metal and bone cement. This permits this fragile population to begin early full weight bearing in a removable brace. PMID:25752013

  6. Ankle-brachial index in HIV infection

    Directory of Open Access Journals (Sweden)

    Martos Francisco

    2009-04-01

    Full Text Available Abstract Prognosis for patients with the human immunodeficiency virus (HIV has improved with the introduction of highly active antiretroviral therapy (HAART. Evidence over recent years suggests that the incidence of cardiovascular disease is increasing in HIV patients. The ankle-brachial index (ABI is a cheap and easy test that has been validated in the general population. Abnormal ABI values are associated with increased cardiovascular mortality. To date, six series of ABI values in persons with HIV have been published, but none was a prospective study. No agreement exists concerning the risk factors for an abnormal ABI, though its prevalence is clearly higher in these patients than in the general population. Whether this higher prevalence of an abnormal ABI is associated with a higher incidence of vascular events remains to be determined.

  7. Short-term locomotor adaptation to a robotic ankle exoskeleton does not alter soleus Hoffmann reflex amplitude

    Directory of Open Access Journals (Sweden)

    Ferris Daniel P

    2010-07-01

    Full Text Available Abstract Background To improve design of robotic lower limb exoskeletons for gait rehabilitation, it is critical to identify neural mechanisms that govern locomotor adaptation to robotic assistance. Previously, we demonstrated soleus muscle recruitment decreased by ~35% when walking with a pneumatically-powered ankle exoskeleton providing plantar flexor torque under soleus proportional myoelectric control. Since a substantial portion of soleus activation during walking results from the stretch reflex, increased reflex inhibition is one potential mechanism for reducing soleus recruitment when walking with exoskeleton assistance. This is clinically relevant because many neurologically impaired populations have hyperactive stretch reflexes and training to reduce the reflexes could lead to substantial improvements in their motor ability. The purpose of this study was to quantify soleus Hoffmann (H- reflex responses during powered versus unpowered walking. Methods We tested soleus H-reflex responses in neurologically intact subjects (n=8 that had trained walking with the soleus controlled robotic ankle exoskeleton. Soleus H-reflex was tested at the mid and late stance while subjects walked with the exoskeleton on the treadmill at 1.25 m/s, first without power (first unpowered, then with power (powered, and finally without power again (second unpowered. We also collected joint kinematics and electromyography. Results When the robotic plantar flexor torque was provided, subjects walked with lower soleus electromyographic (EMG activation (27-48% and had concomitant reductions in H-reflex amplitude (12-24% compared to the first unpowered condition. The H-reflex amplitude in proportion to the background soleus EMG during powered walking was not significantly different from the two unpowered conditions. Conclusion These findings suggest that the nervous system does not inhibit the soleus H-reflex in response to short-term adaption to exoskeleton assistance

  8. Optimal management of ankle syndesmosis injuries

    Directory of Open Access Journals (Sweden)

    Porter DA

    2014-08-01

    Full Text Available David A Porter, Ryan R Jaggers, Adam Fitzgerald Barnes, Angela M Rund Methodist Sports Medicine/The Orthopedic Specialists, Indianapolis, IN, USA Abstract: Syndesmosis injuries occur when there is a disruption of the distal attachment of the tibia and fibula. These injuries occur commonly (up to 18% of ankle sprains, and the incidence increases in the setting of athletic activity. Recognition of these injuries is key to preventing long-term morbidity. Diagnosis and treatment of these injuries requires a thorough understanding of the normal anatomy and the role it plays in the stability of the ankle. A complete history and physical examination is of paramount importance. Patients usually experience an external rotation mechanism of injury. Key physical exam features include detailed documentation about areas of focal tenderness (syndesmosis and deltoid and provocative maneuvers such as the external rotation stress test. Imaging workup in all cases should consist of radiographs with the physiologic stress of weight bearing. If these images are inconclusive, then further imaging with external rotation stress testing or magnetic resonance imaging are warranted. Nonoperative treatment is appropriate for stable injuries. Unstable injuries should be treated operatively. This consists of stabilizing the syndesmosis with either trans-syndesmotic screw or tightrope fixation. In the setting of a concomitant Weber B or C fracture, the fibula is anatomically reduced and stabilized with a standard plate and screw construct. Proximal fibular fractures, as seen in the Maisonneuve fracture pattern, are not repaired operatively. Recent interest is moving toward repair of the deltoid ligament, which may provide increased stability, especially in rehabilitation protocols that involve early weight bearing. Rehabilitation is focused on allowing patients to return to their pre-injury activities as quickly and safely as possible. Protocols initially focus on

  9. Valgus torque in youth baseball pitchers: A biomechanical study.

    Science.gov (United States)

    Sabick, Michelle B; Torry, Michael R; Lawton, Richard L; Hawkins, Richard J

    2004-01-01

    The purpose of this study was to determine the biomechanical and anthropometric factors contributing to elbow valgus torque during pitching. Video data of 14 youth pitchers throwing fastballs were used to calculate shoulder and elbow kinematics and kinetics. Peak elbow valgus torque averaged 18 Nm and occurred just before maximal shoulder external rotation. The magnitude of valgus torque was most closely correlated with the thrower's weight. When subject weight and height were controlled for, maximum shoulder abduction torque and maximum shoulder internal rotation torque were most strongly associated with elbow valgus torque, accounting for 85% of its variance (P <.001). When only kinematic variables were considered, maximum shoulder external rotation accounted for 33% of the variance in valgus torque. Given that the biomechanical variables correlated with peak valgus torque are not easily modifiable, limiting the number of innings pitched is likely the best way to reduce elbow injury in youth pitchers. PMID:15111908

  10. Enhanced Direct Torque Control for Doubly Fed InductionMachine by Active Learning Method Using Indirect MatrixConverter

    Directory of Open Access Journals (Sweden)

    Hamid Behnia

    2012-08-01

    Full Text Available The term Direct Torque Control (DTC originally is referred to a strategy which provides good transient and steady-state performance but it has also some negative aspects, such as non accuracy of flux, torque estimator, torque and flux ripple caused by non-optimality of switching and imprecision in motor model which are known as an inherent characteristic of DTC. This paper explores reducing of flux and torque ripple with using trial and error actively as a method called Active Learning Method (ALM in DTC for Doubly Fed Induction Machine (DFIM which are the motors or generators having twist on both stator and rotor subsequence power is transferred between shaft and system. DFIM is linked to the grid within the stator and the rotor is fed by an Indirect Matrix Converter (IMC. The function of IMC is similar to the direct one, although it has the line and load bridges separated. We analysis the usage of four-step commutation in rectifier stage of IMC to achieve the object of the losses’ reduction which are caused by snubber circuit. ALM adopts itself with torque and flux estimators and estimates the outputs with regards to the errors in torque and flux estimation by repetition therefore achieves the object of omitting inaccuracies in control system hence confirming the effectiveness. Another concept in ALM called Ink Drop Spread (IDS handles different modeling target to predict on the data consequensing a behavior curve in DTC. According to the simulation results, it is proved that a significant torque and stator flux ripple reduction are obtained.

  11. Hallux Valgus, Ankle Osteoarthrosis, and Adult Acquired Flatfoot Deformity : A Review of Three Common Foot&Ankle Pathologies and Their Treatments

    OpenAIRE

    Crevoisier X.; Assal M.; Stankova K.

    2016-01-01

    The pathogenesis of hallux valgus deformity is multifactorial. Conservative treatment can alleviate pain but is unable to correct the deformity. Surgical treatment must be adapted to the type and severity of the deformity. Success of surgical treatment ranges from 80% to 95%, and complication rates range from 10% to 30%. Ankle osteoarthrosis most commonly occurs as a consequence of trauma. Ankle arthrodesis and total ankle replacement are the most common surgical treatments of end stage ankle...

  12. Dynamic and steady state performance comparison of line-start permanent magnet synchronous motors with interior and surface rotor magnets

    Directory of Open Access Journals (Sweden)

    Ogbuka Cosmas

    2016-03-01

    Full Text Available A comprehensive comparison of the dynamic and steady state performance characteristics of permanent magnet synchronous motors (PMSM with interior and surface rotor magnets for line-start operation is presented. The dynamic model equations of the PMSM, with damper windings, are utilized for dynamic studies. Two typical loading scenarios are examined: step and ramp loading. The interior permanent magnet synchronous motor (IPMSM showed superior asynchronous performance under no load, attaining faster synchronism compared to the surface permanent magnet synchronous motor (SPMSM. With step load of 10 Nm at 2 s the combined effect of the excitation and the reluctance torque forced the IPMSM to pull into synchronism faster than the SPMSM which lacks saliency. The ability of the motors to withstand gradual load increase, in the synchronous mode, was examined using ramp loading starting from zero at 2 s. SPMSM lost synchronism at 12 s under 11 Nm load while the IPMSM sustained synchronism until 41 seconds under 40 Nm load. This clearly suggests that the IPMSM has superior load-withstand capability. The superiority is further buttressed with the steady state torque analysis where airgap torque in IPMSM is enhanced by the reluctance torque within 90° to 180° torque angle.

  13. Differential contributions of ankle plantarflexors during submaximal isometric muscle action

    DEFF Research Database (Denmark)

    Masood, Tahir; Bojsen-Møller, Jens; Kalliokoski, Kari K;

    2014-01-01

    The objective of this study was to investigate the relative contributions of superficial and deep ankle plantarflexors during repetitive submaximal isometric contractions using surface electromyography (SEMG) and positron emission tomography (PET). Myoelectric signals were obtained from twelve...

  14. Management of Syndesmotic Ankle Injuries in Children and Adolescents.

    Science.gov (United States)

    Shore, Benjamin J; Kramer, Dennis E

    2016-06-01

    Pediatric ankle injuries are common, especially in athletes; however, the incidence of syndesmosis injuries in children has been scarcely reported. Injuries to the ankle syndesmosis, termed "high ankle sprains," can affect high-level and recreational athletes and have been related to delayed return to play, persistent pain, and adult injuries have been associated with long-term disability. Syndesmotic injuries do occur in children, especially those who participate in sports that involve cutting and pivoting (football, soccer) or sports with rigid immobilization of the ankle (skiing, hockey). Unstable pediatric syndesmosis injuries requiring surgical fixation are often associated with concomitant fibular fracture in skeletally mature children. Physician vigilance and careful clinical examination coupled with appropriate radiographs can determine the extent of the injury in the majority of circumstances. PMID:27100034

  15. Ankle Injuries and Disorders - Multiple Languages: MedlinePlus

    Science.gov (United States)

    ... Supplements Videos & Tools You Are Here: Home → Multiple Languages → All Health Topics → Ankle Injuries and Disorders URL of this page: https://medlineplus.gov/languages/ankleinjuriesanddisorders.html Other topics A-Z A B ...

  16. Clinical anatomy and biomechanics of the ankle in dance.

    Science.gov (United States)

    Russell, Jeffrey A; McEwan, Islay M; Koutedakis, Yiannis; Wyon, Matthew A

    2008-01-01

    The ankle is an important joint to understand in the context of dance because it is the connection between the leg and the foot that establishes lower extremity stability. Its function coordinates with the leg and foot and, thus, it is crucial to the dancer's ability to perform. Furthermore, the ankle is one of the most commonly injured body regions in dance. An understanding of ankle anatomy and biomechanics is not only important for healthcare providers working with dancers, but for dance scientists, dance instructors, and dancers themselves. The bony architecture, the soft tissue restraints, and the locomotive structures all integrate to allow the athletic artistry of dance. Yet, there is still much research to be carried out in order to more completely understand the ankle of the dancer. PMID:19618582

  17. Optimal torque control for SCOLE slewing maneuvers

    Science.gov (United States)

    Bainum, P. M.; Li, Feiyue

    1987-01-01

    The Spacecraft Control Laboratory Experiment (SCOLE) was slewed from one attitude to the required attitude and an integral performance index which involves the control torques was minimized. Kinematic and dynamical equations, optimal control, two-point boundary-value problems, and estimation of unknown boundary conditions are presented.

  18. Cutting the L3 torque tube

    CERN Multimedia

    Laurent Guiraud

    2001-01-01

    Workers cut the torque tube, with a plasma-cutting device on the L3 experiment, which closed with the LEP accelerator in 2000. L3 was housed in a huge red solenoid, which will be taken over by the ALICE detector when the new LHC is completed.

  19. 40 CFR 1065.310 - Torque calibration.

    Science.gov (United States)

    2010-07-01

    ... torque-measurement system with a reference force and a lever arm. (b) Recommended procedure. (1... a proving ring to quantify the reference force, NIST-traceable within ±0.5% uncertainty. (2) Lever-arm length quantification. Quantify the lever arm length, NIST-traceable within ±0.5% uncertainty....

  20. Gravity gradient torque of spacecraft orbiting asteroids

    CERN Document Server

    Wang, Yue

    2013-01-01

    Purpose: This paper presents a full fourth-order model of the gravity gradient torque of spacecraft around asteroids by taking into consideration of the inertia integrals of the spacecraft up to the fourth order, which is an improvement of the previous fourth-order model of the gravity gradient torque. Design, methodology and approach: The fourth-order gravitational potential of the spacecraft is derived based on Taylor expansion. Then the expression of the gravity gradient torque in terms of gravitational potential derivatives is derived. By using the formulation of the gravitational potential, explicit formulations of the full fourth-order gravity gradient torque are obtained. Then a numerical simulation is carried out to verify our model. Findings: We find that our model is more sound and precise than the previous fourth-order model due to the consideration of higher-order inertia integrals of the spacecraft. Numerical simulation results show that the motion of the previous fourth-order model is quite diff...

  1. Are torque values of preadjusted brackets precise?

    Directory of Open Access Journals (Sweden)

    Alessandra Motta Streva

    2011-08-01

    Full Text Available OBJECTIVE: The aim of the present study was to verify the torque precision of metallic brackets with MBT prescription using the canine brackets as the representative sample of six commercial brands. MATERIAL AND METHODS: Twenty maxillary and 20 mandibular canine brackets of one of the following commercial brands were selected: 3M Unitek, Abzil, American Orthodontics, TP Orthodontics, Morelli and Ortho Organizers. The torque angle, established by reference points and lines, was measured by an operator using an optical microscope coupled to a computer. The values were compared to those established by the MBT prescription. RESULTS: The results showed that for the maxillary canine brackets, only the Morelli torque (-3.33º presented statistically significant difference from the proposed values (-7º. For the mandibular canines, American Orthodontics (-6.34º and Ortho Organizers (-6.25º presented statistically significant differences from the standards (-6º. Comparing the brands, Morelli presented statistically significant differences in comparison with all the other brands for maxillary canine brackets. For the mandibular canine brackets, there was no statistically significant difference between the brands. CONCLUSIONS: There are significant variations in torque values of some of the brackets assessed, which would clinically compromise the buccolingual positioning of the tooth at the end of orthodontic treatment.

  2. Overall loudness of steady sounds

    Science.gov (United States)

    Howes, W. L.; Canright, V. R.

    1980-01-01

    Loudness (in sones) and loudness level (in phons) of any sound that is steady for tenths of second can be calculated using computer program derived from new operational theory of loudness. Theory is constructed from psychoacoustic and physiological data on mammalian (monkey) auditory systems. Computer program permits prediction of loudness of any steady sound including, for example, transportation noises, machinery noises, and other environmental noises, with possible additional applications to broadcasting, sound reproduction, establishment and enforcement of noise laws.

  3. Multiple Steady States in Distillation

    OpenAIRE

    Bekiaris, Nikolaos

    1995-01-01

    We study multiple steady states in distillation. We first analyze the simplest case of ternary homogeneous azeotropic mixtures. We show that in the case of infinite reflux and an infinite number of trays (∞/∞ case) one can construct bifurcation diagrams on physical grounds with the distillate flow as the bifurcation parameter. Multiple steady states exist when the distillate flow varies non-monotonically along the continuation path of the bifurcation diagram. We derive a necessary and suffici...

  4. Simulink Model of Direct Torque Control of Induction Machine

    OpenAIRE

    H. F.A. Wahab; Sanusi, H.

    2008-01-01

    Direct torque control (DTC) is one of the most excellent control strategies of torque control in induction machine. It is considered as an alternative to the field oriented control (FOC) or vector control technique. These two control strategies are different on the operation principle but their objectives are the same. They aim to control effectively the torque and flux. Torque control of an induction machine based on DTC strategy has been developed and a comprehensive study is present in thi...

  5. Improvements in direct torque control of induction motors

    OpenAIRE

    Arias Pujol, Antoni

    2001-01-01

    This thesis is mainly devoted to the investigation of speed control methods for three phase cage induction motors with particular emphasis being given to Direct Torque Control (DTC) improved techniques.Classical Direct Torque Control has inherent disadvantages such as: problems during starting resulting from the null states, the compulsory requirement of torque and flux estimators, and torque ripple. In the classical DTC induction motor drive a voltage vector is applied for the entire period,...

  6. Torque ripple minimization of doubly salient permanent-magnet motors

    OpenAIRE

    Chau, KT; Sun, Q; Y. Fan; Cheng, M

    2005-01-01

    Due to the nature of salient poles in both the stator and rotor, the doubly salient permanent-magnet (DSPM) motor suffers from severe torque ripples. In this paper, the torque ripple of DSPM motors is analyzed, and the torque ripple factor is newly derived. A new approach, namely the conduction angle control, is proposed to minimize the torque ripple. Moreover, the genetic algorithm is employed to optimize the corresponding control angles. Computer simulation and experimental results are give...

  7. Spin-Stabilized Spacecrafts: Analytical Attitude Propagation Using Magnetic Torques

    OpenAIRE

    Hélio Koiti Kuga; Maria Cecília F. P. S. Zanardi; Roberta Veloso Garcia

    2009-01-01

    An analytical approach for spin-stabilized satellites attitude propagation is presented, considering the influence of the residual magnetic torque and eddy currents torque. It is assumed two approaches to examine the influence of external torques acting during the motion of the satellite, with the Earth's magnetic field described by the quadripole model. In the first approach is included only the residual magnetic torque in the motion equations, with the satellites in circular or elliptical o...

  8. Direct Torque Control of IPMSM to Improve Torque ripple and Efficiency based on Fuzzy Controller

    Directory of Open Access Journals (Sweden)

    B. Mirzaeian Dehkordi

    2012-09-01

    Full Text Available In this paper, a stator-flux-reference frame control method is proposed in order to control the speed and torque of an Interior Permanent Magnet Synchronous Machine (IPMSM in different loads condition. Direct Torque Control method (DTC based on Space Vector Modulation (SVM is used for control of IPMSM. In the proposed control method, conventional PI controller is used for controlling the stator flux, and torque of the motor. Also, a fuzzy controller is considered to improve the dynamic performance of DTC technique for speed control. In comparison to the conventional reference flux controller methods, this method, in addition, improves the torque profile of the motor drive. Moreover, it reduces copper losses. Simulation results for a 240V, 120A, 2500rpm, IPMSM confirm the appropriate performances of the method.

  9. High Dynamic Torque Capability With Efficiency Optimization Control of Induction Motor Drives

    Directory of Open Access Journals (Sweden)

    K. Barra

    2005-06-01

    Full Text Available The objective of this paper is to present an analysis of how to get high performance of an induction motor drive for both dynamic and steady state operation. In order to improve a good dynamic response in transient (minimize the speed drop, an algorithm for a maximum torque capability of the available maximum inverter current and voltage is presented. When the rotor speed reaches its reference, a loss minimization algorithm is developed to improve high efficiency. Simulation studies show the performance of the proposed work.

  10. Stress Fractures of the Foot and Ankle in Athletes

    OpenAIRE

    Mayer, Stephanie W.; Joyner, Patrick W.; Almekinders, Louis C.; Parekh, Selene G.

    2014-01-01

    Context: Stress fractures of the foot and ankle are a common problem encountered by athletes of all levels and ages. These injuries can be difficult to diagnose and may be initially evaluated by all levels of medical personnel. Clinical suspicion should be raised with certain history and physical examination findings. Evidence Acquisition: Scientific and review articles were searched through PubMed (1930-2012) with search terms including stress fractures and 1 of the following: foot ankle, me...

  11. Accessory Navicular Bone Mimicking Navicular Fracture after Ankle Sprain

    OpenAIRE

    Muharrem Çidem; Murat Uludağ; Kerem Gün; Ülkü Akarırmak

    2011-01-01

    An accessory navicular bone (ANB) is present in 10-30% of normal feet. A morphological classification of ANB on the basis of the radiographic appearance distinguishes three types. Most symptomatic ANBs are of type 2. Although the diagnosis and treatment of sprained ankle are generally straightforward, together with an ANB, it might be misdiagnosed as a fracture. We present a 20-year-old male with type 2 ANB who was misdiagnosed as navicular fracture following sprained ankle. Turk J Phys Med...

  12. Hyaluronic acid as a treatment for ankle osteoarthritis

    OpenAIRE

    Sun, Shu-Fen; Chou, Yi-Jiun; Hsu, Chien-Wei; Chen, Wen-ling

    2009-01-01

    Viscosupplementation refers to the concept of synovial fluid replacement with intra-articular injections of hyaluronic acid (HA) for the relief of pain associated with osteoarthritis (OA). Intra-articular viscosupplementation was approved by the Food and Drug Administration (FDA) in 1997. It is currently indicated only for the treatment of pain associated with knee OA. However, OA can occur in several of the weight-bearing joints of the foot and ankle. Ankle OA produces chronic disability tha...

  13. Inadvertent Screw Stripping During Ankle Fracture Fixation in Elderly Bone

    OpenAIRE

    Dinah, A. Feroz; Mears, Simon C.; Knight, Trevor A.; Soin, Sandeep P.; Campbell, John T.; Belkoff, Stephen M.

    2011-01-01

    Poor screw purchase because of osteoporosis presents difficulties in ankle fracture fixation. The aim of our study was to determine if cortical thickness, unicortical versus bicortical purchase, and bone mineral density are predictors of inadvertent screw stripping and overtightening. Ten paired cadaver ankles (average donor age, 81.7 years; range, 50-97 years) were used for the study. Computed tomography scanning with phantoms of known density was used to determine the bone density along the...

  14. TOTAL ANKLE ARTHROPLASTY: BRAZILIAN EXPERIENCE WITH THE HINTEGRA PROSTHESIS

    OpenAIRE

    Nery, Caio; Fernandes, Túlio Diniz; Réssio, Cibele; Fuchs, Mauro Luiz; Godoy Santos, Alexandre Leme de; Ortiz, Rafael Trevisan

    2015-01-01

    Ankle arthrosis is becoming more and more common. The search for solutions that preserve joint function has led to a new generation of prosthesis with three components and more degrees of freedom. This paper presents the results achieved for ten patients treated with the HINTEGRA Prosthesis (Integra, New Deal), through collaborative action between the Foot and Ankle Groups of the Orthopedics and Traumatology divisions of Escola Paulista de Medicina, Unifesp, and the School of Medicine of the ...

  15. Muscle fatigue degrades force sense at the ankle joint.

    OpenAIRE

    Vuillerme, Nicolas; Boisgontier, Matthieu

    2008-01-01

    To investigate the effects of muscle fatigue on force sense at the ankle joint, 10 young healthy adults were asked to perform an isometric contra-lateral force ankle-matching task in two experimental conditions of: (1) no-fatigue and (2) fatigue of the plantar-flexor muscles. Measures of the overall accuracy and the variability of the force matching performances were determined using the absolute error and the variable error, respectively. Results showed less accurate and less consistent forc...

  16. MR imaging of the lateral collateral ligaments after ankle sprain

    International Nuclear Information System (INIS)

    35 patients with ankle sprain were examined by MRI and stress radiographs. 13 were operated afterwards, 22 patients underwent a functional conservative therapy and were examined by MRI and stress radiographs and second time after three months. MRI reports were correct in 12 of 13 operated cases. After conservative therapy we did not find any disrupted ankle ligament. MRI showed intact ligaments thickened by scar. (orig./MG)

  17. EFFECTS OF ANKLE JOINT COOLING ON PERONEAL SHORT LATENCY RESPONSE

    OpenAIRE

    J. Ty Hopkins; Iain Hunter; Todd McLoda

    2006-01-01

    While cryotherapy has direct physiological effects on contractile tissues, the extent to which joint cooling affects the neuromuscular system is not well understood. The purpose of the study was to detect changes in ankle dynamic restraint (peroneal short latency response and muscle activity amplitude) during inversion perturbation following ankle joint cryotherapy. A 2x3 factorial design was used to compare reaction time and EMG amplitude data of treatment conditions (cryotherapy and control...

  18. Developing A mobile App for the Rehabilitation of Ankle Sprains

    OpenAIRE

    Suzanne McDonough; Christopher Bleakley; Christopher Nugent; Joseph Rafferty; Jonathan Synnott; Adele Boyd; Katie Hunter

    2015-01-01

    Background: Musculoskeletal injuries are common and costly. Ankle sprains are one of the most common such injuries, carrying significant risk of persistent disabling symptoms. Rehabilitation has been shown to be more effective than standard conservative approaches for musculoskeletal injuries. The use of a mobile app to present rehabilitation guidance may offer a more accessible, engaging and effective solution to ankle sprain rehabilitation. Several existing apps target the prevention and re...

  19. Comparison of Ankle Proprioception Between Pregnant and Non Pregnant Women

    OpenAIRE

    Preetha R; John Solomon M

    2011-01-01

    Pregnant women report falls especially during their third trimester. Physiological changes along with ligament laxity can affect the joint proprioception in this population. This study was conducted to compare the ankle proprioception between pregnant and non pregnant women. Thirty pregnant and 30 non pregnant women were included in the study and the position of ankles were recorded by a digital camera placed 60 cms away from the feet of the subject. UTHSCSA Image tool software version 3.0. w...

  20. Proprioceptive exercises for ankle ligament injury: a CAT

    OpenAIRE

    Raúl Aguilera Eguía; Alexis Espinoza Salinas; Edson Zafra Santos; Tamara Aguilera Eguía

    2013-01-01

    This CAT (Critically Appraised Topic) answered the question: In recreational athletes suffering from chronic ankle sprain, can proprioceptive exercises reduce its recurrence?The clinical question was analyzed in three parts: patient, intervention and outcome. The purpose was to test the validity, results and effectiveness of proprioceptive exercises in recreational athletes suffering from chronic ankle sprain to reduce its recurrence from the article "Effectiveness of proprioceptive exercises...

  1. The ANKLE TRIAL (ANKLE treatment after injuries of the ankle ligaments: what is the benefit of external support devices in the functional treatment of acute ankle sprain? : a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Witjes Suzanne

    2012-02-01

    Full Text Available Abstract Background Acute lateral ankle ligament injuries are very common problems in present health care. Still there is no hard evidence about which treatment strategy is superior. Current evidence supports the view that a functional treatment strategy is preferable, but insufficient data are present to prove the benefit of external support devices in these types of treatment. The hypothesis of our study is that external ankle support devices will not result in better outcome in the treatment of acute ankle sprains, compared to a purely functional treatment strategy. Overall objective is to compare the results of three different strategies of functional treatment for acute ankle sprain, especially to determine the advantages of external support devices in addition to functional treatment strategy, based on balance and coordination exercises. Methods/design This study is designed as a randomised controlled multi-centre trial with one-year follow-up. Adult and healthy patients (N = 180 with acute, single sided and first inversion trauma of the lateral ankle ligaments will be included. They will all follow the same schedule of balancing exercises and will be divided into 3 treatment groups, 1. pressure bandage and tape, 2. pressure bandage and brace and 3. no external support. Primary outcome measure is the Karlsson scoring scale; secondary outcomes are FAOS (subscales, number of recurrent ankle injuries, Visual Analogue Scales of pain and satisfaction and adverse events. They will be measured after one week, 6 weeks, 6 months and 1 year. Discussion The ANKLE TRIAL is a randomized controlled trial in which a purely functional treated control group, without any external support is investigated. Results of this study could lead to other opinions about usefulness of external support devices in the treatment of acute ankle sprain. Trial registration Netherlands Trial Register (NTR: NTR2151

  2. Managing ankle ligament sprains and tears: current opinion

    Directory of Open Access Journals (Sweden)

    McGovern RP

    2016-03-01

    Full Text Available Ryan P McGovern,1 RobRoy L Martin,1,2 1Department of Physical Therapy, Rangos School of Health Sciences, Duquesne University, 2Centers for Sports Medicine – University of Pittsburgh, Pittsburgh, PA, USA Abstract: The purpose of this paper is to present a current review of pathoanatomical features, differential diagnosis, objective assessment, intervention, and clinical course associated with managing lateral ankle ligament sprains. Proper diagnosis and identification of affected structures should be obtained through history and objective assessment. From this information, an individualized evidence-based intervention plan can be developed to enable recovery while decreasing the risk of reinjury. An appropriate evaluation is needed not only to determine the correct diagnosis but also to allow for grading and determining the prognosis of the injury in those with an acute lateral ankle sprain. Examination should include an assessment of impairments as well as a measure of activity and participation. Evidence-based interventions for those with an acute lateral ankle sprain should include weight bearing with bracing, manual therapy, progressive therapeutic exercises, and cryotherapy. For those with chronic ankle instability (CAI, interventions should include manual therapy and a comprehensive rehabilitation program. It is essential to understand the normal clinical course for athletes who sustain a lateral ankle sprain as well as risk factors for an acute injury and CAI. Risk factors for both an acute lateral ankle sprain and CAI include not using an external support and not participating in an appropriate exercise program. Incorporating the latest evidence-based rehabilitation techniques provides the best course of treatment for athletes with an acute ankle sprain or CAI. Keywords: reinjury, chronic ankle instability, rehabilitation techniques, diagnosis, intervention, athlete

  3. Ultrasound-guided intervention in the ankle and foot.

    Science.gov (United States)

    Drakonaki, Eleni E; Allen, Gina M; Watura, Roland

    2016-01-01

    In this comprehensive review, we discuss the main interventions performed in the foot and ankle for Achilles tendinopathy, Morton's neuromas and Plantar fasciitis as well as techniques for intra-articular and peritendinous injections. We present the different imaging techniques and injectable agents that can be used in clinical practice, trying to help the reader decide the most appropriate way of managing the patient with a problem in the ankle and foot. PMID:26537692

  4. Fractures and Soft Tissue Injuries of the Feet and Ankle

    OpenAIRE

    English, Edward

    1985-01-01

    An accurate clinical diagnosis of foot and ankle pain can be made by a history, physical examination and routine X-rays of the affected part. Each problem has a specific treatment; however, fractures and dislocations around the foot and ankle can be thought of in an organized fashion by proper physical examination and then the appropriate treatment. Fractures and soft tissue injuries can be treated rationally by understanding the mechanism of injury and the possibility of subsequent deformity...

  5. The ANKLE TRIAL (ANKLE treatment after injuries of the ankle ligaments): what is the benefit of external support devices in the functional treatment of acute ankle sprain? : a randomised controlled trial

    OpenAIRE

    Witjes Suzanne; Gresnigt Femke; van den Bekerom Michel PJ; Olsman Jan G; van Dijk Niek C

    2012-01-01

    Abstract Background Acute lateral ankle ligament injuries are very common problems in present health care. Still there is no hard evidence about which treatment strategy is superior. Current evidence supports the view that a functional treatment strategy is preferable, but insufficient data are present to prove the benefit of external support devices in these types of treatment. The hypothesis of our study is that external ankle support devices will not result in better outcome in the treatme...

  6. Treatment of acute ankle ligament injuries: a systematic review

    OpenAIRE

    Petersen, Wolf; Rembitzki, Ingo Volker; Koppenburg, Andreas Gösele; Ellermann, Andre; Liebau, Christian; Brüggemann, Gerd Peter; Best, Raymond

    2013-01-01

    Background Lateral ankle sprains are common musculoskeletal injuries. Objectives The objective of this study was to perform a systematic literature review of the last 10 years regarding evidence for the treatment and prevention of lateral ankle sprains. Data source Pubmed central, Google scholar. Study eligibility criteria Meta-analysis, prospective randomized trials, English language articles. Interventions Surgical and non-surgical treatment, immobilization versus functional treatment, diff...

  7. Ankle injuries of elite male Iranian gymnasts and anthropometric characteristics

    OpenAIRE

    GHASEMPOUR, Hadi; Rajabi, Reza; Alizadeh, Mohammad Hossein; TAVANAI, Ali

    2014-01-01

    In men's gymnastics, the ankle is the most frequently injured part of the body. However, very few studies have been conducted to determine the roles of various risk factors so that the rate of these injuries can be reduced. The aim of this study was to determine the relationship between anthropometric factors (intrinsic risk factors) and the ankle injuries incurred by elite male gymnasts in the Iranian Premier League and Division One. This research was cross sectional correlation study in its...

  8. Improved Torque Control Performance in Direct Torque Control using Optimal Switching Vectors

    OpenAIRE

    Muhd Zharif Rifqi Zuber Ahmadi; Auzani Jidin; Maaspaliza Azri; Khairi Rahim; Tole Sutikno

    2015-01-01

    This paper presents the significant improvement of Direct Torque Control (DTC) of 3-phases induction machine using a Cascaded H-Bidge Multilevel Inverter (CHMI). The largest torque ripple and variable switching frequency are known as the major problem founded in DTC of induction motor. As a result, it can diminish the performance induction motor control. Therefore, the conventional 2-level inverter has been replaced with CHMI the in order to increase the performance of the motor either in dyn...

  9. Designing a sensorless torque estimator for direct torque control of an induction motor

    OpenAIRE

    Tsoutsas, Athanasios

    2009-01-01

    Nowadays, transportation is a major cause of air pollution. Electric propulsion could replace the internal combustion engines of automobiles and reduce the emission of exhaust gases. The propulsion of an electric vehicle requires the design of an accurate electromagnetic torque estimator and an efficient control system in order to control the speed of the vehicle. This concept is conveyed through this thesis. An electromagnetic torque calculator of an induction motor is designed in the Simuli...

  10. Research on Torque Ratio Based on the Steering Wheel Torque Characteristic for Steer-by-Wire System

    Directory of Open Access Journals (Sweden)

    Yandong Han

    2014-01-01

    Full Text Available Steer-by-wire system can improve the performance of vehicle handling stability. Removing the mechanical linkages between the front wheels and the steering wheel leads to a key technique of force feedback for steer-by-wire system. In view of the characteristic of variable torque transmission ratio for steer-by-wire system, this paper proposes a method for designing torque ratio based on the steering wheel torque characteristic for steer-by-wire system. It converts the torque ratio design into equivalent assist torque design by analyzing their relationship. It achieves the torque ratio design at different conditions based on the negative equivalent assist torque characteristic curve. Simulations and vehicle experiments are conducted by the proposed method, and the results show that the design goal has been achieved and the steering wheel torque characteristic obtained is very similar to that of the reference car.

  11. Syndesmotic Malreduction after Ankle ORIF; Is Radiography Sufficient?

    Directory of Open Access Journals (Sweden)

    Alireza Manafi Rasi

    2013-12-01

    Full Text Available   Background: Ankle fractures, especially those resulting from external rotation mechanisms are associated with injury to the distal tibiofibular syndesmosis. Some authors have recommended performing CT scanning after open ankle surgery to evaluate the reduction of syndesmosis. In this current study, we aimed to investigate the sensitivity of plain radiography in diagnosing syndesmosis malreduction after open reduction and internal fixation (ORIF in patients with ankle fractures.   Methods: Thirty patients with ankle fractures participated in this prospective study. ORIFs were performed with respect to all of the technical guidelines shown in orthopedic literature for exact syndesmosis reduction, such as fibular length and proper settings. In the operating room, plain radiography was performed in anteroposterior, mortise and lateral views to assess whether syndesmosis was malreduced. If malreduction was detected, the patient was revised. As the gold standard, patients underwent postoperative bilateral CT scanning to investigate the syndesmosis reduction which was then compared to the healthy side. Finally, the sensitivity of plain radiography in the diagnosis of syndesmosis malreduction was determined by comparing this method to CT scanning. Results: In both of the methods we did not find any patient with syndesmosis malreduction. Hence, the sensitivity of plain radiography was determined 100%. Conclusion: Based on our findings, there is no need to perform CT scanning to evaluate syndesmosis reduction after ankle ORIF in patients with ankle fractures. Plain radiography is sufficient and has satisfactory sensitivity in these patients.

  12. Performances improvements and torque ripple minimization for VSI fed induction machine with direct control torque.

    Science.gov (United States)

    Abdelli, R; Rekioua, D; Rekioua, T

    2011-04-01

    This paper describes a torque ripple reduction technique with constant switching frequency for direct torque control (DTC) of an induction motor (IM). This method enables a minimum torque ripple control. In order to obtain a constant switching frequency and hence a torque ripple reduction, we propose a control technique for IM. It consists of controlling directly the electromagnetic torque by using a modulated hysteresis controller. The design methodology is based on space vector modulation (SVM) of electrical machines with digital vector control. MATLAB simulations supported with experimental study are used. The simulation and experimental results of this proposed algorithm show an adequate dynamic to IM; however, the research can be extended to include synchronous motors as well. The implementation of the proposed algorithm is described. It doesn't require any PI controller in the torque control loop. The hardware inverter is controlled digitally using a Texas Instruments TMS320F240 digital signal processor (DSP) with composed C codes for generating the required references. The results obtained from simulation and experiments confirmed the feasibility of the proposed strategy compared to the conventional one. PMID:21193193

  13. Cogging Torque and Acoustic Noise Reduction in High Torque BLDC Motors by Teeth Pairings

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Min [Halla Climate Control Co. (Korea, Republic of); Hwang, Sang Moon [Pusan National University (Korea, Republic of)

    1999-03-01

    This paper investigates reduction of acoustic noise and cogging torque in a BLDC motor with larger stator slot open width. Using energy method, cogging torque is analytically determined with airgap MMF function and airgap permeance function and confirmed by FEM analysis. It show that the cogging torque is firstly governed by N{sub L} G{sub NL} B{sub NL} with the fundamental period of N{sub L}, where N{sub L} is the least common multiple of the number of slots and the number of poles, G{sub NL}, airgap permeance function and B{sub NL}, airgap MMF function. It also shows that there exist several tooth width which minimizes the cogging torque, for the motors that smaller slot open width or stator teeth notching is not available. And it proposes a teeth pairing with two different tooth width which can effectively eliminate the cogging torque and thus the acoustic noise. Experimental results show that the proposed teeth pairing reduces the cogging torque by 85% and the acoustic noise by 3.1 dB. (author). 9 refs., 13 figs., 1 tab.

  14. Ankle and subtalar synovitis in a ball-and-socket ankle joint causing posterolateral painful coarse crepitus: a case report.

    Science.gov (United States)

    Fan, Ka Yuk; Lui, Tun Hing

    2014-01-01

    A 17-year-old girl with bilateral ball-and-socket ankles reported left medial heel pain. Her left heel had gone into a varus position on tiptoeing, and a painful clunk had occurred when returning to normal standing. The clunk persisted after physiotherapy and treatment with an orthosis. Subtalar arthroscopy and peroneal tendoscopy showed mild diffuse synovitis of the ankle joint, especially over the posterior capsule, and a patch of inflamed and fibrotic synovium at the posterolateral corner of the subtalar joint. The clunk subsided immediately after arthroscopic synovectomy and had not recurred during 5 years of follow-up. We found no other reported cases of ankle and subtalar synovitis occurring in patients with a ball-and-socket ankle joint. PMID:25179452

  15. Ankle mechanics during sidestep cutting implicates need for 2-degrees of freedom powered ankle-foot prostheses

    Directory of Open Access Journals (Sweden)

    Evandro M. Ficanha

    2015-04-01

    Full Text Available The ankle joint of currently available powered prostheses is capable of controlling one degree of freedom (DOF, focusing on improved mobility in the sagittal plane. To increase agility, the requirements of turning in prosthesis design need to be considered. Ankle kinematics and kinetics were studied during sidestep cutting and straight walking. There were no significant differences between the ankle sagittal plane mechanics when comparing sidestep cutting and straight walking; however, significant differences were observed in ankle frontal plane mechanics. During straight walking, the inversion-eversion (IE angles were smaller than with sidestep cutting. The ankle that initiated the sidestep cutting showed progressively increasing inversion from 2 to 13 degrees while the following contralateral step showed progressively decreasing inversion from 8 to –4 degrees during normal walking speed. The changes in IE kinematics were the most significant during sidestep cutting compared with straight walking. The IE moments of the step that initiated the sidestep cutting were always in eversion, acting as a braking moment opposing the inverting motion. This suggests that an ankle-foot prosthesis with active DOFs in the sagittal and frontal planes will increase the agility of gait for patients with limb loss.

  16. Evaluating fracture risk in acute ankle sprains: Any news since the Ottawa Ankle Rules? A systematic review.

    Science.gov (United States)

    Jonckheer, Pascale; Willems, Tine; De Ridder, Roel; Paulus, Dominique; Holdt Henningsen, Kirsten; San Miguel, Lorena; De Sutter, An; Roosen, Philip

    2016-03-01

    Background Ankle sprain is frequently encountered, both in primary care and in emergency departments. Since 1992, the Ottawa ankle rules (OAR) can assist clinicians in determining whether an X-ray should be performed to exclude a fracture. Several guidelines recommend the use of OAR based on a systematic review from 2003. Ten years later, one can wonder if this recommendation should be changed. Objective To review systematically the current evidence on the most accurate method to assess the fracture risk after an ankle sprain in adults. Methods A methodical search for systematic reviews, meta-analyses and primary studies was carried out in Medline, Cochrane Database of systematic reviews, Embase, Pedro, CINAHL, Medion and specific guideline search engines. At least two independent researchers performed selection, quality appraisal (with validated checklists) and data extraction. Results One systematic review and 21 primary studies were selected. Sensitivity and specificity of the OAR range from 92-100% and from 16-51%, respectively. To improve the OAR specificity, other tools are proposed such as the Bernese ankle rules. Vibrating tuning fork test and ultrasound could be useful in patient with OAR positive to decrease the need for radiographs. No evidence was found in favour of the use of magnetic resonance imaging (MRI) or computed tomography (CT) in the acute phase of ankle sprain. Conclusion The findings confirm the value of the OAR at ruling out fractures after an ankle sprain and propose other or additional tools to decrease the need for X-rays. PMID:26691309

  17. Tailoring spin-orbit torque in diluted magnetic semiconductors

    KAUST Repository

    Li, Hang

    2013-05-16

    We study the spin orbit torque arising from an intrinsic linear Dresselhaus spin-orbit coupling in a single layer III-V diluted magnetic semiconductor. We investigate the transport properties and spin torque using the linear response theory, and we report here: (1) a strong correlation exists between the angular dependence of the torque and the anisotropy of the Fermi surface; (2) the spin orbit torque depends nonlinearly on the exchange coupling. Our findings suggest the possibility to tailor the spin orbit torque magnitude and angular dependence by structural design.

  18. Research on Drag Torque Prediction Model for the Wet Clutches

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Considering the surface tension effect and centrifugal effect, a mathematical model based on Reynolds equation for predicting the drag torque of disengage wet clutches is presented. The model indicates that the equivalent radius is a function of clutch speed and flow rate. The drag torque achieves its peak at a critical speed. Above this speed, drag torque drops due to the shrinking of the oil film. The model also points out that viscosity and flow rate effects on drag torque. Experimental results indicate that the model is reasonable and it performs well for predicting the drag torque peak.

  19. Iatrogenic posterior tibial nerve division during a combined anterior ankle arthroscopy with an additional posterolateral portal.

    Science.gov (United States)

    Abdul-Jabar, Hani B; Bhamra, Jagmeet; Quick, Tom J; Fox, Michael

    2016-01-01

    Ankle arthroscopy is an important diagnostic and therapeutic technique in the management of ankle disorders. Nowadays ankle arthroscopy provides good to excellent results (up to 90%) in the treatment of certain intra-articular disorders. Due to the superficial location of ankle joint and the abundance of overlying neurovascular structures, complications reported in ankle arthroscopy are greater than those reported in other joints. We present the first reported case of a complete division of the posterior tibial nerve during an anterior ankle arthroscopy combined with an additional posterolateral portal. This was due to a poorly controlled use of the arthroscopic instruments. PMID:27197613

  20. Iatrogenic posterior tibial nerve division during a combined anterior ankle arthroscopy with an additional posterolateral portal

    Science.gov (United States)

    Abdul-Jabar, Hani B; Bhamra, Jagmeet; Quick, Tom J; Fox, Michael

    2016-01-01

    Ankle arthroscopy is an important diagnostic and therapeutic technique in the management of ankle disorders. Nowadays ankle arthroscopy provides good to excellent results (up to 90%) in the treatment of certain intra-articular disorders. Due to the superficial location of ankle joint and the abundance of overlying neurovascular structures, complications reported in ankle arthroscopy are greater than those reported in other joints. We present the first reported case of a complete division of the posterior tibial nerve during an anterior ankle arthroscopy combined with an additional posterolateral portal. This was due to a poorly controlled use of the arthroscopic instruments. PMID:27197613

  1. Transient and steady state modelling of a coupled WECS

    Science.gov (United States)

    Nathan, G. K.; Tan, J. K.

    The paper presents a method for simulation of a wind turbine using a dc motor. The armature and field voltages of the dc motor are independently regulated to obtain torque-speed characteristics which correspond to those of a wind turbine at different wind speeds. The mass moment of inertia of the wind turbine is represented by adding a rotating mass to a parallel shaft which is positively coupled to the motor shaft. To verify the method of simulation, an American multiblade wind turbine is chosen, loaded by coupling to a centrifugal pump. Using the principle of conservation of energy and characteristics of both constituent units, two mathematical models are proposed: one for steady state operation and another for the transient state. The close comparison between the theoretical and the experimental results validates the proposed models and the method of simulation. The experimental method is described and the results of the experimental and theoretical investigation are presented.

  2. Steady reconstruction process - development, testing and comparison in ultrasonic testing

    International Nuclear Information System (INIS)

    The fault parameters can be extracted from a few data of high quality in steady test procedures. The boundary conditions for the successful use of such a process were researched and found, so that by using theoretical models for the elasto-dynamic interaction of fault and ultrasonics, a concentration of wavefronts instead of resonances and a wide band careful collection of data makes a physical interpretation in the form of specific geometry torques possible. Models of the interaction of ultrasonics and faults for two fault geometries (cracks and pores) were developed which permit the calculation of A scans of any bandwidth and with any angle of scatter for the direct and mode converted parts of the elastic ultrasonic scatter wave. The curved pressure and shear waves including the mode converted bending fields over an angular range of 360deg were experimentally recorded. Their agreement including the additional wavefronts caused by the close field of the crack bending field is close. Classification of torques is done on two examples (crack, cylinder) for evaluation purposes. It was found that a classification was possible according to the sign of the a1 polynomial coefficient. (orig./HP)

  3. Displaceable Spur Gear Torque Controlled Driver and Method

    Science.gov (United States)

    Cook, Joseph S., Jr. (Inventor)

    1996-01-01

    Methods and apparatus are provided for a torque driver including a laterally displaceable gear support member to carry an output spur gear. A biasing assembly biases the output spur gear into engagement with a pinion to which is applied an input torque greater than a desired output torque limit for a threaded fastener such as a nut or screw. A coiled output linkage connects the output spur gear with a fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. A gauged selector mechanism is provided to laterally displace multiple driven members for fasteners arranged in differing configurations. The torque limit is selectably adjustable and may be different for fasteners within the same fastener configuration.

  4. Displaceable spur gear torque controlled driver and method

    Science.gov (United States)

    Cook, Joseph S., Jr.

    1994-08-01

    Methods and apparatus are provided for a torque driver including a laterally displaceable gear support member to carry an output spur gear. A biasing assembly biases the output spur gear into engagement with a pinion to which is applied an input torque greater than a desired output torque limit for a threaded fastener such as a nut or screw. A coiled output linkage connects the output spur gear with a fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. A gauged selector mechanism is provided to laterally displace multiple driver members for fasteners arranged in differing configurations. The torque limit is selectably adjustable and may be different for fasteners within the same fastener configuration.

  5. Combined Effects of Stretching and Resistance Training on Ankle Joint Flexibility

    Directory of Open Access Journals (Sweden)

    E. Kato

    2013-01-01

    Full Text Available The purpose of the present study was to clarify the combined effects of stretching and resistance training on the active and passive dorsiflexion range of motion of ankle joint. Sixteen young adult men were randomly assigned to a training (n=8 or a control (n=8 group. The training group trained one leg for the combined program of static calf stretching and dorsiflexors resistance training program (STR+TR and the other leg for static stretching program only (STR. The training group executed stretching of both legs every day and resistance training every other day for six weeks. After the training program, in STR+TR side, both active and passive dorsiflexion range of motions significantly (P<0.05 increased and also isometric maximal voluntary dorsiflexion torque increased, while in STR side, only passive dorsiflexion range of motion increased. In passive dorsiflexion range of motion, increased dorsiflexion ROM was accompanied by increased tendon elongation not muscle elongation. In conclusion, the combined program of stretching for calf muscles and resistance training for dorsiflexors increases active as well as passive dorsiflexion range of motion, while static calf stretching program is effective only for the increase in passive dorsiflexion range of motion.

  6. Isokinetic analysis of ankle and ground reaction forces in runners and triathletes

    Directory of Open Access Journals (Sweden)

    Natália Mariana Silva Luna

    2012-09-01

    Full Text Available OBJECTIVE: To analyze and compare the vertical component of ground reaction forces and isokinetic muscle parameters for plantar flexion and dorsiflexion of the ankle between long-distance runners, triathletes, and nonathletes. METHODS: Seventy-five males with a mean age of 30.26 (±6.5 years were divided into three groups: a triathlete group (n=26, a long-distance runner group (n = 23, and a non-athlete control group. The kinetic parameters were measured during running using a force platform, and the isokinetic parameters were measured using an isokinetic dynamometer. RESULTS: The non-athlete control group and the triathlete group exhibited smaller vertical forces, a greater ground contact time, and a greater application of force during maximum vertical acceleration than the long-distance runner group. The total work (180º/s was greater in eccentric dorsiflexion and concentric plantar flexion for the non-athlete control group and the triathlete group than the long-distance runner group. The peak torque (60º/s was greater in eccentric plantar flexion and concentric dorsiflexion for the control group than the athlete groups. CONCLUSIONS: The athlete groups exhibited less muscle strength and resistance than the control group, and the triathletes exhibited less impact and better endurance performance than the runners.

  7. Radiology of chronic diseases of the ankle joint

    International Nuclear Information System (INIS)

    The etiology of chronic diseases of the ankle joint comprises a wide spectrum including chronic inflammatory processes and chronic degenerative, tumorous and neuropathic processes, as well as some specific syndromes based on chronic changes of the ankle joint. Of the inflammatory processes, chronic juvenile arthritis (JVC) is the most common disease. However, also Reiter disease, psoriasis or chronic monoarthritid diseases such as gout, as well as granulomatous diseases (tuberculosis, sarcoidosis) and fungal infections, may affect the ankle joint in a chronic course. Chronic degenerative changes are usually secondary due to abnormal positioning of the joint constituents or repetitive trauma. Neuropathic changes, as frequently seen in the course of diabetes, present with massive osseous destruction and malposition of the articular constituents. Chronic osseous as well as cartilaginous and synovial changes are seen in hemoplici patients. Chronic traumatic changes are represented by pigmented villonodular synovitis (PVNS), and chondromatosis, both with a predilection for the ankle joint. Due to the possibilities of magnetic resonance imaging (MRI), diagnosis of chronic ankle changes includes chronic ligamentous, tendinous and soft tissue changes. With the use MRI, specific syndromes can be defined which particularly affect the ankle joint in a chronic way, such as the os trigonum syndrome, the anterolateral impingement syndrome and the sinus tarsi syndrome. Nevertheless, plain film radiographs are still the basic element of any investigation. MRI, however, can be potentially used as a second investigation, saving an unnecessary cascade of investigations with ultrasound and CT. The latter investigations are used only with very specific indications, for instance CT for subtle bone structures and sonography for a limited investigation of tendons or evaluation of fluid. Particularly due to the possibilities of MRI and the development of special gradient-echo imaging or

  8. Real time implementation of viable torque and flux controllers and torque ripple minimization algorithm for induction motor drive

    International Nuclear Information System (INIS)

    Field oriented control (FOC) and direct torque control (DTC) are becoming the industrial standards for induction motors torque and flux control. This paper aims to give a contribution for a detailed comparison between these two control techniques, emphasizing their advantages and disadvantages. The performance of these two control schemes is evaluated in terms of torque and flux ripple and their transient response to step variations of the torque command. Moreover, a new torque and flux ripple minimization technique is also proposed to improve the performance of the DTC drive. Based on the experimental results, the analysis has been presented

  9. A Non-Unity Torque Sharing Function for Torque Ripple Minimization of Switched Reluctance Generators in Wind Power Systems

    Directory of Open Access Journals (Sweden)

    Hye-Ung Shin

    2015-10-01

    Full Text Available This paper deals with a new torque ripple minimization method for a Switched Reluctance Generator (SRG. Although, the SRG has many advantages including simple and robust construction, and high power density as a generator, it has not been widely employed in the industry. One of the major drawbacks of the SRG is its high torque ripple that results in high noise operation of the generator. In this paper, a non-unity Torque Sharing Function (TSF is proposed to minimize the torque ripple over a wide speed range of operation. Simulations as well as experimental results are presented to verify the effectiveness of the proposed torque ripple minimization technique.

  10. Prophylactic Ankle Taping and Bracing: A Numbers-Needed-to-Treat and Cost-Benefit Analysis.

    Science.gov (United States)

    Olmsted, Lauren C.; Vela, Luzita I.; Denegar, Craig R.; Hertel, Jay

    2004-03-01

    OBJECTIVE: Taping and bracing are thought to decrease the incidence of ankle sprains; however, few investigators have addressed the effect of preventive measures on the rate of ankle sprains. Our purpose was to examine the effectiveness of ankle taping and bracing in reducing ankle sprains by applying a numbers-needed-to-treat (NNT) analysis to previously published studies. DATA SOURCES: We searched PubMed, CINAHL, SPORT Discus, and PEDro for original research from 1966 to 2002 with key words ankle taping, ankle sprains, injury incidence, prevention, ankle bracing, ankle prophylaxis, andnumbers needed to treat. We eliminated articles that did not address the effects of ankle taping or bracing on ankle injury rates using an experimental design. DATA SYNTHESIS: The search produced 8 articles, of which 3 permitted calculation of NNT, which addresses the clinical usefulness of an intervention by providing estimates of the number of treatments needed to prevent 1 injury occurrence. In a study of collegiate intramural basketball players, the prevention of 1 ankle sprain required the taping of 26 athletes with a history of ankle sprain and 143 without a prior history. In a military academy intramural basketball program, prevention of 1 sprain required bracing of 18 athletes with a history of ankle sprain and 39 athletes with no history. A study of ankle bracing in competitive soccer players produced an NNT of 5 athletes with a history of previous sprain and 57 without a prior injury. A cost- benefit analysis of ankle taping versus bracing revealed taping to be approximately 3 times more expensive than bracing. CONCLUSIONS/RECOMMENDATIONS: Greater benefit is achieved in applying prophylactic ankle taping or bracing to athletes with a history of ankle sprain, compared with those without previous sprains. The generalizability of these results to other physically active populations is unknown. PMID:15085217

  11. An Optical Torque Sensor for Robotic Applications

    Science.gov (United States)

    Palli, G.; Pirozzi, S.

    2013-10-01

    In this article, the design and the experimental evaluation of a torque sensor based on optoelectronic components integrated in a suitably designed plastic compliant frame are reported. The sensing principle is based on the variation of the photocurrent flowing through a PhotoDetector (PD) as a consequence of the variation of its relative position, with respect of a Light Emitting Diode (LED), caused by the deformation of the sensor frame under the effect of the torque to be measured. The sensor frame has been designed as a planar structure that shows preferential deformation along a rotation axis normal to the symmetry plane. This article reports the sensor basic working principle, the compliant frame design and verification, the calibration of the sensor, and the experimental evaluation of its sensitivity and frequency response.

  12. Manipulation of spin transfer torque using light

    Science.gov (United States)

    Rontani, Massimo; Vendelbjerg, Karsten; Sham, Lu

    We show that the spin transfer torque induced by a spin-polarized current on a nanomagnet as the current flows through a semiconductor-nanomagnet-semiconductor junction is externally controlled by shining the junction off-resonantly with a strong laser beam. The excitonic coherence driven by the laser dresses the virtual electron-hole pairs coupling conduction and valence bands and inducing an evanescent state in the proximity of the nanomagnet. The Fano-like quantum interference between this localized state and the continuum spectrum is different in the two spin channels and hence it dramatically alters the spin transport, leading to the coherent control of the spin transfer torque. This work is supported by EU-FP7 Marie Curie Initial Training Network INDEX.

  13. Responses of spinal dorsal horn neurons to foot movements in rats with a sprained ankle.

    Science.gov (United States)

    Kim, Jae Hyo; Kim, Hee Young; Chung, Kyungsoon; Chung, Jin Mo

    2011-05-01

    Acute ankle injuries are common problems and often lead to persistent pain. To investigate the underlying mechanism of ankle sprain pain, the response properties of spinal dorsal horn neurons were examined after ankle sprain. Acute ankle sprain was induced manually by overextending the ankle of a rat hindlimb in a direction of plantarflexion and inversion. The weight-bearing ratio (WBR) of the affected foot was used as an indicator of pain. Single unit activities of dorsal horn neurons in response to plantarflexion and inversion of the foot or ankle compression were recorded from the medial part of the deep dorsal horn, laminae IV-VI, in normal and ankle-sprained rats. One day after ankle sprain, rats showed significantly reduced WBRs on the affected foot, and this reduction was partially restored by systemic morphine. The majority of deep dorsal horn neurons responded to a single ankle stimulus modality. After ankle sprain, the mean evoked response rates were significantly increased, and afterdischarges were developed in recorded dorsal horn neurons. The ankle sprain-induced enhanced evoked responses were significantly reduced by morphine, which was reversed by naltrexone. The data indicate that movement-specific dorsal horn neuron responses were enhanced after ankle sprain in a morphine-dependent manner, thus suggesting that hyperactivity of dorsal horn neurons is an underlying mechanism of pain after ankle sprain. PMID:21389306

  14. Range of Motion of the Ankle According to Pushing Force, Gender and Knee Position

    Science.gov (United States)

    Cho, Kang Hee; Lee, Hyunkeun

    2016-01-01

    Objective To investigate the difference of range of motion (ROM) of ankle according to pushing force, gender and knee position. Methods One hundred and twenty-eight healthy adults (55 men, 73 women) between the ages of 20 and 51, were included in the study. One examiner measured the passive range of motion (PROM) of ankle by Dualer IQ Inclinometers and Commander Muscle Testing. ROM of ankle dorsiflexion (DF) and plantarflexion (PF) according to change of pushing force and knee position were measured at prone position. Results There was significant correlation between ROM and pushing force, the more pushing force leads the more ROM at ankle DF and ankle PF. Knee flexion of 90° position showed low PF angle and high ankle DF angle, as compared to the at neutral position of knee joint. ROM of ankle DF for female was greater than for male, with no significant difference. ROM of ankle PF for female was greater than male regardless of the pushing force. Conclusion To our knowledge, this is the first study to assess the relationship between pushing force and ROM of ankle joint. There was significant correlation between ROM of ankle and pushing force. ROM of ankle PF for female estimated greater than male regardless of the pushing force and the number of measurement. The ROM of the ankle is measured differently according to the knee joint position. Pushing force, gender and knee joint position are required to be considered when measuring the ROM of ankle joint. PMID:27152277

  15. Steady-State Process Modelling

    DEFF Research Database (Denmark)

    Cameron, Ian; Gani, Rafiqul

    illustrate the “equation oriented” approach as well as the “sequential modular” approach to solving complex flowsheets for steady state applications. The applications include the Williams-Otto plant, the hydrodealkylation (HDA) of toluene, conversion of ethylene to ethanol and a bio-ethanol process.......This chapter covers the basic principles of steady state modelling and simulation using a number of case studies. Two principal approaches are illustrated that develop the unit operation models from first principles as well as through application of standard flowsheet simulators. The approaches...

  16. Direct Torque Control of the Asynchronous Motor

    Directory of Open Access Journals (Sweden)

    Peter Girovský

    2008-05-01

    Full Text Available This contribution deals with the proposal of direct torque control (DTC of asynchronous motor (AMwith the help of fuzzy logic. The whole structure of DTC is designed in software Matlab – Simulink, the fuzzy regulator is designed with the help of Fuzzy Toolbox. The results of DTC with fuzzy regulator are compared with DTC with the help of Depenbrock method and DTC with the help of Takahashi method.

  17. Torque Control of Electrorheological Fluidic Actuators

    OpenAIRE

    Vitrani, Marie-Aude; Nikitczuk, Jason; Morel, Guillaume; Mavroidis, Constantinos

    2004-01-01

    In this paper, the experimental closed loop torque control of electro-rheological fluids (ERF) based actuators for haptic applications is performed. ERFs are liquids that respond mechanically to electric fields by changing their properties, such as viscosity and shear stress, electroactively. Using the electrically controlled rheological properties of ERFs, we developed actuators for haptic devices that can resist human operator forces in a controlled and tunable fashion. In this study, the E...

  18. Torque control of switched reluctance motors

    OpenAIRE

    Moron Fernandez, Carlos; Garcia Garcia, Alfonso; Tremps Guerra, Enrique; Somolinos Sanchez, Jose Andres

    2011-01-01

    This paper presents the performance of an instantaneous torque control method. The simulation and experimental results illustrate the capability of Switched Reluctance Motors (SRM) being used in the motor drive industry. Based on experimental data, the advantages of this control method and its disadvantages in practical implementation were studied. The model used in the simulation is the linear magnetic model which has the 12/8 structure, the same structure as the experimental switched re...

  19. Direct Torque Control of the Asynchronous Motor

    OpenAIRE

    Peter Girovský; Jaroslava Žilková; Ľubomír Cibuľa; Jaroslav Timko

    2008-01-01

    This contribution deals with the proposal of direct torque control (DTC) of asynchronous motor (AM)with the help of fuzzy logic. The whole structure of DTC is designed in software Matlab – Simulink, the fuzzy regulator is designed with the help of Fuzzy Toolbox. The results of DTC with fuzzy regulator are compared with DTC with the help of Depenbrock method and DTC with the help of Takahashi method.

  20. Static magnetic forces and torques in ATLAS

    International Nuclear Information System (INIS)

    The magnetic forces acting on the various metallic objects around the ATLAS detector, are the subject of the given paper. A system designer could use the information on global forces and torque acting on various components, obtained in this report, to optimize them. The results of force calculations could also serve as additional criteria for the replacement of the magnetic baseline material of various structures by nonmagnetic ones

  1. Nanocavity optomechanical torque magnetometry and RF susceptometry

    OpenAIRE

    Wu, Marcelo; Wu, Nathanael L. -Y.; Firdous, Tayyaba; Sani, Fatemeh Fani; Losby, Joseph E.; Freeman, Mark R.; Barclay, Paul E.

    2016-01-01

    Nanophotonic optomechanical devices allow observation of nanoscale vibrations with sensitivity that has dramatically advanced metrology of nanomechanical structures [1-9] and has the potential to similarly impact studies of nanoscale physical systems [10, 11]. Here we demonstrate this potential with a nanophotonic optomechanical torque magnetometer and radio-frequency (RF) magnetic susceptometer. Exquisite readout sensitivity provided by a nanocavity integrated within a torsional nanomechanic...

  2. Collision Sensing Using Force/Torque Sensor

    OpenAIRE

    Yu-Quan Leng; Zheng-Cang Chen; Xu He; Yang Zhang; Wei Zhang

    2016-01-01

    Collision sensing including collision position, collision direction, and force size could make robots smoothly interact with environment, so that the robots can strongly adapt to the outside world. Skin sensor imitates principles of human skin using special material and physical structure to obtain collision information, but this method has some disadvantages, such as complex design, low sampling rate, and poor generality. In this paper, a new method using force/torque sensor to calculate col...

  3. An ironless armature brushless torque motor

    Science.gov (United States)

    Studer, P. A.

    1973-01-01

    A high torque motor with improved servo mechanism is reported. Armature windings are cast into an epoxy cylinder and armature conductors are integrally cast with an aluminum mounting ring which provides thermal conductance directly into the structure. This configuration eliminates magnetic hysteresis because there is no relative motion between the rotating magnetic field and any stationary iron. The absence of destabilization forces provides a fast electrical response compared with a typical torquer of conventional construction.

  4. Magnetorheological torque transmission devices with permanent magnets

    Science.gov (United States)

    Böse, H.; Gerlach, T.; Ehrlich, J.

    2013-02-01

    A novel type of magnetorheological (MR) clutch whose magnetic circuit contains a combination of a permanent magnet and an electromagnet is described. Without the support of the electromagnet, the permanent magnet generates a magnetic field in the MR fluid shear gap which enables the MR clutch to transmit a torque without the supply of any electric energy. Hence, the operational states of this clutch are reversed with respect to the common MR clutches equipped with an electromagnet only. Three different MR clutches with hybrid magnetic circuits containing permanent magnet and electromagnet were designed, manufactured and tested. The three clutches differ in their number of mechanical parts which can rotate with respect to each other as well as in their size and weight and in their maximum transmittable torque. The largest MR clutch is capable to transmit torques up to nearly 800 Nm. The designs of the three novel MR clutches and the results of the mechanical tests upon variation of the coil current are presented in this paper.

  5. Space Suit Joint Torque Measurement Method Validation

    Science.gov (United States)

    Valish, Dana; Eversley, Karina

    2012-01-01

    In 2009 and early 2010, a test method was developed and performed to quantify the torque required to manipulate joints in several existing operational and prototype space suits. This was done in an effort to develop joint torque requirements appropriate for a new Constellation Program space suit system. The same test method was levied on the Constellation space suit contractors to verify that their suit design met the requirements. However, because the original test was set up and conducted by a single test operator there was some question as to whether this method was repeatable enough to be considered a standard verification method for Constellation or other future development programs. In order to validate the method itself, a representative subset of the previous test was repeated, using the same information that would be available to space suit contractors, but set up and conducted by someone not familiar with the previous test. The resultant data was compared using graphical and statistical analysis; the results indicated a significant variance in values reported for a subset of the re-tested joints. Potential variables that could have affected the data were identified and a third round of testing was conducted in an attempt to eliminate and/or quantify the effects of these variables. The results of the third test effort will be used to determine whether or not the proposed joint torque methodology can be applied to future space suit development contracts.

  6. [Ankle sprains: from diagnosis to management. the physiatric view].

    Science.gov (United States)

    Moreira, Vítor; Antunes, Filipe

    2008-01-01

    Ankle injuries are the most frequently encountered injuries in clinical practice. They are often managed by general practicians, and not only by orthopaedic or physiatric physicians. This injury is usually non-complicated, but some care should be taken to assure an adequate management and to exclude severe lesions. The stability of the ankle is necessary for functional activity of lower extremity, allowing walking and participation in other high demanding activities like running or jumping. There is a constant concern in adopting the best diagnostic and treatment procedures to enhance the recovery and to prevent the chronic joint instability. According to this, there should be proposed comprehensive strategies focusing the rehabilitation view. The ankle is a complex articular structure with contributions from the talocrural, subtalar, and inferior tibiofibular joints. The full understanding of the functional anatomy and biomechanics is the first step for the evaluation of the etiologic factors. The recognition of the mechanism of injury, and the risk factors, should be carefully addressed to make an accurate diagnosis, proper management and to implement prophylactic measures, knowing that the lateral ligamentous complex is the most commonly injured. As always, diagnosis can be made taking an adequate history, performing a thorough physical examination, and when necessary, requesting complementary studies. The priority in initial assessment it's to clear out some severe complications, like fractures, that can mimic or that can be associated with ankle sprains. Although the conventional radiology is suitable for most cases, that has been greatly improved through the institution of the Ottawa Rules, in selected patients the severity of the damage is best evaluated with other imaging resources. Treatment of acute ankle sprains depends on the severity of the injury. Most acute lateral ligament injuries are best treated nonsurgically and will regain satisfactory ankle

  7. The Effects of Kinesiotape Applied to the Lateral Aspect of the Ankle: Relevance to Ankle Sprains – A Systematic Review

    Science.gov (United States)

    Wilson, Brendan; Bialocerkowski, Andrea

    2015-01-01

    Objective To identify, evaluate and synthesise evidence on the effect of kinesiotape applied to the lateral aspect of the ankle, through a systematic review of quantitative studies. Data Sources A search for quantitative studies was undertaken using key terms of “kinesiotape” and “ankle” in seven electronic databases, using the maximum date ranges. Databases included: the Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, Medline, Physiotherapy Evidence Database, Scopus, SPORTDiscus and Web of Science. Study Selection Database hits were evaluated against explicit inclusion criteria. From 107 database hits, 8 quantitative studies were included. Data Extraction Two independent reviewers appraised the methodological rigour of the studies using the McMaster Critical Review Form for Quantitative Studies. Data were extracted on participant characteristics, kinesiotape parameters, comparison interventions, outcome measures and findings. Data Syntheses Most studies (n=7) had good to very good methodological rigour. Meta-analysis was not possible due to heterogeneity in participants, interventions and outcome measures. No adverse events were reported. Kinesiotape may produce different effects in healthy and injured ankles. In healthy ankles, kinesiotape may increase postural control, whereas in injured ankles it may improve proprioception, plantarflexor endurance and the performance of activities. These trends were identified from a small body of evidence including 276 participants. Conclusions It is recommended that kinesiotape may be used in clinical practice to prevent lateral ankle injuries (through its effects on postural control) and manage lateral ankle injuries due to its positive effects on proprioception, muscle endurance and activity performance. It appears that kinesiotape may not provide sufficient mechanical support to improve postural control in unstable ankles. Adverse events associated with kinseiotape are unlikely. PMID

  8. A new formulation of the understeer coefficient to relate yaw torque and vehicle handling

    Science.gov (United States)

    Bucchi, F.; Frendo, F.

    2016-06-01

    The handling behaviour of vehicles is an important property for its relation to performance and safety. In 1970s, Pacejka did the groundwork for an objective analysis introducing the handling diagram and the understeer coefficient. In more recent years, the understeer concept is still mentioned but the handling is actively managed by direct yaw control (DYC). In this paper an accurate analysis of the vehicle handling is carried out, considering also the effect of drive forces. This analysis brings to a new formulation of the understeer coefficient, which is almost equivalent to the classical one, but it can be obtained by quasi-steady-state manoeuvres. In addition, it relates the vehicle yaw torque to the understeer coefficient, filling up the gap between the classical handling approach and DYC. A multibody model of a Formula SAE car is then used to perform quasi-steady-state simulations in order to verify the effectiveness of the new formulation. Some vehicle set-ups and wheel drive arrangements are simulated and the results are discussed. In particular, the handling behaviours of the rear wheel drive (RWD) and the front wheel drive (FWD) architectures are compared, finding an apparently surprising result: for the analysed vehicle the FWD is less understeering than for RWD. The relation between the yaw torque and the understeer coefficient allows to understand this behaviour and opens-up the possibility for different yaw control strategies.

  9. Monotonic return to steady nonequilibrium

    Czech Academy of Sciences Publication Activity Database

    Maes, C.; Netočný, Karel; Wynants, B.

    2011-01-01

    Roč. 107, č. 1 (2011), "010601-1"-"010601-4". ISSN 0031-9007 Institutional research plan: CEZ:AV0Z10100520 Keywords : nonequilibrium steady state * Lyapunov function * entropy production Subject RIV: BE - Theoretical Physics Impact factor: 7.370, year: 2011 http://link.aps.org/doi/10.1103/PhysRevLett.107.010601

  10. Staffing in a Steady State.

    Science.gov (United States)

    Owens, J. A.

    1982-01-01

    Options for faculty utilization in a steady state are examined, with consideration for their economy or ability to increase turnover or flexibility: early retirement, part retirement, retraining, exchange with other institutions or industry, and fixed-term appointments or lecturer positions. (MSE)

  11. Steady-State Process Modelling

    DEFF Research Database (Denmark)

    Cameron, Ian; Gani, Rafiqul

    2011-01-01

    illustrate the “equation oriented” approach as well as the “sequential modular” approach to solving complex flowsheets for steady state applications. The applications include the Williams-Otto plant, the hydrodealkylation (HDA) of toluene, conversion of ethylene to ethanol and a bio-ethanol process....

  12. Early Intra-Articular Complement Activation in Ankle Fractures

    Directory of Open Access Journals (Sweden)

    Hagen Schmal

    2014-01-01

    Full Text Available Cytokine regulation possibly influences long term outcome following ankle fractures, but little is known about synovial fracture biochemistry. Eight patients with an ankle dislocation fracture were included in a prospective case series and matched with patients suffering from grade 2 osteochondritis dissecans (OCD of the ankle. All fractures needed external fixation during which joint effusions were collected. Fluid analysis was done by ELISA measuring aggrecan, bFGF, IL-1β, IGF-1, and the complement components C3a, C5a, and C5b-9. The time periods between occurrence of fracture and collection of effusion were only significantly associated with synovial aggrecan and C5b-9 levels (P<0.001. Furthermore, synovial expressions of both proteins correlated with each other (P<0.001. Although IL-1β expression was relatively low, intra-articular levels correlated with C5a (P<0.01 and serological C-reactive protein concentrations 2 days after surgery (P<0.05. Joint effusions were initially dominated by neutrophils, but the portion of monocytes constantly increased reaching 50% at day 6 after fracture (P<0.02. Whereas aggrecan and IL-1β concentrations were not different in fracture and OCD patients, bFGF, IGF-1, and all complement components were significantly higher concentrated in ankle joints with fractures (P<0.01. Complement activation and inflammatory cell infiltration characterize the joint biology following acute ankle fractures.

  13. Magnetic resonance imaging of ankle ligaments and tendon injuries

    International Nuclear Information System (INIS)

    Today MRI allows evaluation of the integrity of injured ankle ligaments. The major difficulty in MRI is inconsistency in visualization by inadequate appreciation of the three-dimensional orientation of each ankle ligament. Using this technique, 52 patients with sprained ankles underwent MRI. The integrity of rupture of the collateral lateral ligaments was obtained in all 52 ankles. Full-lenght visualization is essential for evaluation of the ankle ligaments with MRI. In these 52 patients the angle of tilt on the stress X-ray was compared with the rate of MRI findings showing an injury affecting two ligaments. We found that none of the patients in whom the angle of lateral tilt was less than 5 had rupture of two laterial ligaments, while 32% of patients with angles of tilt of 6-14 and 42% of those with angles of tilt over 15 on stress X-ray had two ruptured lateral ligaments. The advantages of MRI are that it offers the best visualization of the extent of the tendon lesion. MRI, however, seems to be superior to US in detecting and quantifying lesions of the Achilles tendon. Therefore, MRI may be indicated in particularly difficult cases of tendons injuries in the foot. (orig.)

  14. Total ankle arthroplasty with severe preoperative varus deformity.

    Science.gov (United States)

    Hanselman, Andrew E; Powell, Brian D; Santrock, Robert D

    2015-04-01

    Advancements in total ankle arthroplasty (TAA) over the past several decades have led to improved patient outcomes and implant survivorship. Despite these innovations, many implant manufacturers still consider a preoperative coronal plane deformity greater than 10° a relative contraindication to TAA. Without proper intraoperative alignment, these implants may experience abnormal wear and hardware failure. Correcting these deformities, often through the use of soft tissue procedures and/or osteotomies, not only increases the difficulty of a case, but also the intraoperative time and radiation exposure. The authors report a case in which a 54-year-old man with a severe right ankle varus deformity of 29° underwent successful TAA using the INBONE II Prophecy total ankle system (Wright Medical Technology, Inc, Memphis, Tennessee) and additional soft tissue reconstruction. Intraoperatively, the patient's coronal deformity was corrected to 1.8°. At 8 months postoperatively, the patient ambulated without restriction and had substantial improvement in validated patient outcome scores, specifically the Academy of Orthopaedic Surgeons Foot and Ankle Module and the Short Form Health Survey-12 This unique report documents the first time that this particular implant, with an exclusive preoperative computed tomography-derived patient-specific guide, has been used effectively for a severe preoperative varus deformity greater than 20° without the need for an osteotomy. Future studies should be directed toward the prospective evaluation of different total ankle implant systems and their outcomes with severe coronal plane deformity, specifically computed tomography-derived patient-specific guided implants. PMID:25901630

  15. [PARTICULAR QUALITIES OF DIAGNOSTIC ACUTE LATERAL ANKLE LIGAMENT INJURIES].

    Science.gov (United States)

    Krasnoperov, S N; Shishka, I V; Golovaha, M L

    2015-01-01

    Delayed diagnosis of acute lateral ankle ligaments injury and subsequent inadequate treatment leads to the development of chronic instability and rapid progression of degenerative processes in the joint. The aim of our work was to improve treatment results by developing an diagnostic algorithm and treatment strategy of acute lateral ankle ligament injuries. The study included 48 patients with history of acute inversion ankle injury mechanism. Diagnostic protocol included clinical and radiological examination during 48 hours and after 7-10 days after injury. According to the high rate of inaccurate clinical diagnosis in the first 48 hours of the injury a short course of conservative treatment for 7-10 days is needed with follow-up and controlling clinical and radiographic instability tests. Clinical symptoms of ankle inversion injury showed that the combination of local tenderness in the projection of damaged ligaments, the presence of severe periarticular hematoma in the lateral department and positive anterior drawer and talar tilt tests in 7-10 days after the injury in 87% of cases shows the presence of ligament rupture. An algorithm for diagnosis of acute lateral ankle ligament injury was developed, which allowed us to determine differential indications for surgical repair of the ligaments and conservative treatment of these patients. PMID:27089717

  16. Screening for Peripheral Artery Disease and Cardiovascular Disease Risk Assessment with Ankle Brachial Index in Adults

    Science.gov (United States)

    ... Force Recommendations Screening for Peripheral Artery Disease and Cardiovascular Disease Risk Assessment with Ankle Brachial Index in Adults The ... Recommendation | 1 Screening for Peripheral Artery Disease and Cardiovascular Disease Risk Assessment with Ankle Brachial Index in Adults Potential ...

  17. 78 FR 34708 - Proposed Information Collection (Ankle Conditions Disability Benefits Questionnaire) Activity...

    Science.gov (United States)

    2013-06-10

    ... AFFAIRS Proposed Information Collection (Ankle Conditions Disability Benefits Questionnaire) Activity... Control No. 2900--NEW (Ankle Conditions Disability Benefits Questionnaire)'' in any correspondence. During... Conditions Disability Benefits Questionnaire, VA Form 21-0960M-2. OMB Control Number: 2900--NEW...

  18. 78 FR 68908 - Agency Information Collection (Ankle Conditions Disability Benefits Questionnaire) Under OMB Review

    Science.gov (United States)

    2013-11-15

    ... AFFAIRS Agency Information Collection (Ankle Conditions Disability Benefits Questionnaire) Under OMB... Questionnaire)'' in any correspondence. FOR FURTHER INFORMATION CONTACT: Crystal Rennie, Enterprise Records... Disability Benefits Questionnaire)''. SUPPLEMENTARY INFORMATION: Title: Ankle Conditions Disability...

  19. Ankle Injuries Among United States High School Sports Athletes, 2005–2006

    OpenAIRE

    Nelson, Alex J.; Collins, Christy L; Yard, Ellen E.; Fields, Sarah K; Comstock, R. Dawn

    2007-01-01

    Context: Ankle injuries are the most common sport-related injuries. To date, no studies have been published that use national data to present a cross-sport, cross-sex analysis of ankle injuries among US high school athletes.

  20. Assessment of AK (Above Knee) Prosthesis with Different Ankle Assembly Using GRF Pattern in Stance Phase

    Science.gov (United States)

    Kim, Sung-Min; Kim, Sung-Jae; Bae, Ha-Suk

    In this study, ground reaction force (GRF), absolute symmetry index (ASI) and coefficient of variation (CV) of fixed, single-axis and multi-axis prosthetic ankle assemblies were investigated by biomechanical evaluation of above knee amputees. In the experiments, 37 normal male volunteers, two male and two female Above Knee (AK) amputees GRF data were tested with fixed, single-axis and multi-axis prosthetic ankle assembly. A gait analysis was carried out to derive the ratio of GRF to weight as the percentage of total stance phase for ten points. The results showed that fixed-axis ankle assembly was superior to other two ankle assemblies for forwarding and braking forces. Multi-axis ankle was relatively superior to other two ankle assemblies for gait balancing and movement of the mass center. Single-axis ankle was relatively superior to the other two ankle assemblies for CV and ASI of GRF.

  1. Bevel gear driver and method having torque limit selection

    Science.gov (United States)

    Cook, Joseph S., Jr. (Inventor)

    1994-01-01

    This invention comprises a torque drive mechanism utilizing axially translatable, mutually engageable transmission members having mating crown gears, driven and driving members with a three-element drive train being biased together by resilient means or by a fluid actuator system, the apparatus being operable to transmit a precisely controlled degree of torque to a driven member. The apparatus is applicable for use in hand tools and as a replacement for impact torque drivers, torque wrenches, motorized screw drivers, or the like, wherein the applied torque must be precisely controlled or limited. The bevel torque drive includes a drive gear which is axially displaceable and rotatable within cylindrical driver housing, a rotatable intermediate gear, and an output gear. Key rotationally secures displaceable gear with respect to input shaft but permits axial movement therebetween. A thrust bearing is preferably connected to the lower end of shaft for support to reduce play and friction between shaft and a transmission joint disc during rotation of the gear train. Coaxially mounted coiled spring is footed against displaceable gear for biasing the displaceable gear toward and into engagement with the intermediate gear for driving intermediate gear and output gear. Torque control is achieved by the use of straight or spiral beveled gears which are of configurations adapted to withdraw from mutual engagement upon the torque exceeding a predetermined limit. The novel, advantageous features of the invention include the configuration of the mating, crown gear sets and the axially translatable, slidable drive gear. The mechanism is capable of transmitting a high degree of torque within a narrow, compact transmission housing. The compact size and narrow, elongated configuration of the housing is particularly applicable for use in hand tools and in multiple torque driver mechanisms in which it is necessary to drive multiple fasteners which are located in close proximity. Prior

  2. Bevel gear driver and method having torque limit selection

    Science.gov (United States)

    Cook, Joseph S., Jr.

    1994-08-01

    This invention comprises a torque drive mechanism utilizing axially translatable, mutually engageable transmission members having mating crown gears, driven and driving members with a three-element drive train being biased together by resilient means or by a fluid actuator system, the apparatus being operable to transmit a precisely controlled degree of torque to a driven member. The apparatus is applicable for use in hand tools and as a replacement for impact torque drivers, torque wrenches, motorized screw drivers, or the like, wherein the applied torque must be precisely controlled or limited. The bevel torque drive includes a drive gear which is axially displaceable and rotatable within cylindrical driver housing, a rotatable intermediate gear, and an output gear. Key rotationally secures displaceable gear with respect to input shaft but permits axial movement therebetween. A thrust bearing is preferably connected to the lower end of shaft for support to reduce play and friction between shaft and a transmission joint disc during rotation of the gear train. Coaxially mounted coiled spring is footed against displaceable gear for biasing the displaceable gear toward and into engagement with the intermediate gear for driving intermediate gear and output gear. Torque control is achieved by the use of straight or spiral beveled gears which are of configurations adapted to withdraw from mutual engagement upon the torque exceeding a predetermined limit. The novel, advantageous features of the invention include the configuration of the mating, crown gear sets and the axially translatable, slidable drive gear. The mechanism is capable of transmitting a high degree of torque within a narrow, compact transmission housing. The compact size and narrow, elongated configuration of the housing is particularly applicable for use in hand tools and in multiple torque driver mechanisms in which it is necessary to drive multiple fasteners which are located in close proximity. Prior

  3. Torque Ripple Reduction in Direct Torque Control Based Induction Motor using Intelligent Controllers

    Science.gov (United States)

    Sudhakar, Ambarapu; Vijaya Kumar, M.

    2015-09-01

    This paper presents intelligent control scheme together with conventional control scheme to overcome the problems with uncertainties in the structure encountered with classical model based design of induction motor drive based on direct torque control (DTC). It allows high dynamic performance to be obtained with very simple hysteresis control scheme. Direct control of the torque and flux is achieved by proper selection of inverter voltage space vector through a lookup table. This paper also presents the application of intelligent controllers like neural network and fuzzy logic controllers to control induction machines with DTC. Intelligent controllers are used to emulate the state selector of the DTC. With implementation of intelligent controllers the system is also verified and proved to be operated stably with reduced torque ripple. The proposed method validity and effectiveness has been verified by computer simulations using Matlab/Simulink®. These results are compared with the ones obtained with a classical DTC using proportional integral speed controller.

  4. Electromagnetic torque signal estimation in a direct torque control system for electrical machines

    Energy Technology Data Exchange (ETDEWEB)

    Orille, A.L. [Polytechnic Univ. of Catalonia, Dept. of Electrical Engineering, Barcelona (Spain); Sowilam, G.M.A. [Helwan Univ., Dept. of Electrical Engineering, Barcelona (Spain); Villada Duque, F. [Univ. of Antioquia, Dept. of Electrical Engineering, Barcelona (Spain)

    2000-08-01

    Recently, the emerging technology of artificial neural networks (ANNs) has been successfully used in a variety of applications in industrial control. This work proposes the use of multilayer neural networks for the estimation of the electromagnetic torque signal in a direct torque control system (DTC). The simulation of the DTC complete system, including the induction motor, the power electronics supply system, and the control unit, is developed using the program SIMULINK of Matlab. Once selected the right structure of the neural network, on-line testing is realised as a part of the DTC system to determinate its stability and liability. The performance of the system including the neural network for the estimation of the electromagnetic torque signal is compared with the simulation of the system without using neural networks. (orig.)

  5. A CFD-informed quasi-steady model of flapping wing aerodynamics

    Science.gov (United States)

    Nakata, Toshiyuki; Liu, Hao; Bomphrey, Richard J.

    2016-01-01

    Aerodynamic performance and agility during flapping flight are determined by the combination of wing shape and kinematics. The degree of morphological and kinematic optimisation is unknown and depends upon a large parameter space. Aimed at providing an accurate and computationally inexpensive modelling tool for flapping-wing aerodynamics, we propose a novel CFD (computational fluid dynamics)-informed quasi-steady model (CIQSM), which assumes that the aerodynamic forces on a flapping wing can be decomposed into the quasi-steady forces and parameterised based on CFD results. Using least-squares fitting, we determine a set of proportional coefficients for the quasi-steady model relating wing kinematics to instantaneous aerodynamic force and torque; we calculate power with the product of quasi-steady torques and angular velocity. With the quasi-steady model fully and independently parameterised on the basis of high-fidelity CFD modelling, it is capable of predicting flapping-wing aerodynamic forces and power more accurately than the conventional blade element model (BEM) does. The improvement can be attributed to, for instance, taking into account the effects of the induced downwash and the wing tip vortex on the force generation and power consumption. Our model is validated by comparing the aerodynamics of a CFD model and the present quasi-steady model using the example case of a hovering hawkmoth. It demonstrates that the CIQSM outperforms the conventional BEM while remaining computationally cheap, and hence can be an effective tool for revealing the mechanisms of optimization and control of kinematics and morphology in flapping-wing flight for both bio-flyers and unmanned air systems.

  6. Functional performance of a total ankle replacement: thorough assessment by combining gait and fluoroscopic analyses

    OpenAIRE

    Cenni, Francesco; Leardini, Alberto; Pieri, Maddalena; Berti, Lisa; Belvedere, Claudio; Romagnoli, Matteo; Giannini, Sandro

    2013-01-01

    BACKGROUND: A thorough assessment of patients after total ankle replacement during activity of daily living can provide complete evidence of restored function in the overall lower limbs and replaced ankle. This study analyzes how far a possible restoration of physiological mobility in the replaced ankle can also improve the function of the whole locomotor apparatus. METHODS: Twenty patients implanted with an original three-part ankle prosthesis were analyzed 12 months after surgery d...

  7. Ankle sprain : Subjective and objective measures of functional impairment and treatment

    OpenAIRE

    Leanderson, Johan

    1996-01-01

    This thesis is based upon a series of studies were performed in order to provide more informationabout the etiology of late symptoms after ankle sprain, most often referred to as functional instabilityof the ankle joint. In a retrospective study of basketball players, the incidence of ankle sprains and theprevalence of late symptoms after such an injury were investigated. The injury incidence was cal-culated to 5.5 ankle injuries /1000 activity hours, which is three to four times higher than ...

  8. Effects of Kinesio taping on joint position sense of the ankle

    OpenAIRE

    Seo, Hyun-Do; Kim, Min-Young; Choi, Jung-Eun; Lim, Ga-Hee; Jung, Seong-In; Park, So-Hyun; Cheon, Song-Hee; Lee, Hae-Yong

    2016-01-01

    [Purpose] The purpose of this study was to examine the effect of Kinesio taping on the joint position sense of the ankle. [Subjects and Methods] The subjects of this study were 26 nomal adults who had experienced ankle sprain. Kinesio taping was applied over the ankle medial ligament and ankle lateral ligament with eight pattern reinforcement taping. Joint position sense was measured using isokinetic equipment (Biodex System 4 pro dynamometer, Biodex Medical systems Inc., USA) during dorsifle...

  9. Cogging Torque Reduction in Surface Permanent Magnet Motors Using Taguchi Experiment Design and Finite Element Method

    OpenAIRE

    S. Rashidaee; S.Asghar Gholamian

    2012-01-01

    in this paper, use the Taguchi experiment design method for achieving optimal design to reduce cogging torque and torque ripple of a surface permanent magnet motor. Cogging torque is one cause of vibration and noise, so reducing cogging torque is an important issue Results from simulations, indicate reduction of cogging torque and torque ripple while increasing the average of motor’s output torque. How do simulations and achieve the optimum design, by using the Taguchi method and simulations ...

  10. Improved Torque Control Performance of Direct Torque Control for 5-Phase Induction Machine

    OpenAIRE

    Logan Raj Lourdes Victor Raj; Auzani Jidin; Kasrul Abdul Karim; Tole Sutikno; R. Sundram; Mohd Hatta Jopri

    2013-01-01

    In this paper, the control of five-phase induction machine using Direct Torque Control (DTC) is presented. The general D-Q model of five-phase induction machine is discussed. The de-coupled control of stator flux and electromagnetic torque based on hysteresis controller similar to conventional DTC is applied to maintain the simplicity of the system. Three sets of look-up tables consist of voltage vectors with different amplitude that selects the  most optimal voltage vectors according motor o...

  11. Ankle manual therapy for individuals with post-acute ankle sprains: description of a randomized, placebo-controlled clinical trial

    Directory of Open Access Journals (Sweden)

    Fisher Beth E

    2010-10-01

    Full Text Available Abstract Background Ankle sprains are common within the general population and can result in prolonged disablement. Limited talocrural dorsiflexion range of motion (DF ROM is a common consequence of ankle sprain. Limited talocrural DF ROM may contribute to persistent symptoms, disability, and an elevated risk for re-injury. As a result, many health care practitioners use hands-on passive procedures with the intention of improving talocrural joint DF ROM in individuals following ankle sprains. Dosage of passive hands-on procedures involves a continuum of treatment speeds. Recent evidence suggests both slow- and fast-speed treatments may be effective to address disablement following ankle sprains. However, these interventions have yet to be longitudinally compared against a placebo study condition. Methods/Design We developed a randomized, placebo-controlled clinical trial designed to test the hypotheses that hands-on treatment procedures administered to individuals following ankle sprains during the post-acute injury period can improve short-, intermediate-, and long-term disablement, as well as reduce the risk for re-injury. Discussion This study is designed to measure the clinical effects of hands-on passive stretching treatment procedures directed to the talocrural joint that vary in treatment speed during the post-acute injury period, compared to hands-on placebo control intervention. Trial Registration http://www.clinicaltrials.gov identifier NCT00888498.

  12. Exercise and ankle sprain injuries: a comprehensive review.

    Science.gov (United States)

    Calatayud, Joaquin; Borreani, Sebastien; Colado, Juan Carlos; Flandez, Jorge; Page, Phil; Andersen, Lars L

    2014-02-01

    Ankle sprains are common in team sports and sports played on courts, and often result in structural and functional alterations that lead to a greater reinjury risk. Specific exercises are often used to promote neuromuscular improvements in the prevention and rehabilitation of ankle injuries. This literature review summarizes the neuromuscular characteristics of common ankle sprains and the effectiveness of exercise as an intervention for improving neuromuscular function and preventing reinjury. Our review found that appropriate exercise prescription can increase static and dynamic balance and decrease injury recurrence. In particular, the addition of dynamic activities in the exercise program can be beneficial because of the anticipatory postural adjustments identified as a key factor in the injury mechanism. PMID:24565825

  13. Peroneal muscle weakness in female basketballers following chronic ankle sprain.

    Science.gov (United States)

    Rottigni, S A; Hopper, D

    1991-01-01

    Female A-grade basketballers were examined for invertor and evertor muscle strength. Two test groups participated. The injured group were players who had persisting disability following ankle sprains. The control group were players who had never sustained an ankle sprain. Test apparatus was the Orthotron isokinetic dynamometer at contraction speed of 180° per second. Trends towards higher invertor and evertor strength in uninjured group when compared with the injured group found in the present study have been supported by one other report. Invertors were found to be significantly stronger than evertors in both injured and uninjured groups, with the exception of the dominant leg of the uninjured group. A significant weakness in non-dominant evertors of the uninjured group was detected. Dominance did not significantly alter strength differences in the invertor or evertor muscle groups within the uninjured population. The clinical importance of strengthening the peroneal muscles in ankle sprain rehabilitation is discussed, and further research considerations provided. PMID:25025187

  14. Arthrography of the ankle joint in chronic instability

    International Nuclear Information System (INIS)

    Papers on arthrography of injuries of the lateral ligaments of the ankle relate mainly to recent distortion of the joint. Arthrography performed at a later stage after injury generally is considered useless. In fact, changes in chronic instability are observed; they are subtle and consist either of small recesses adjacent to the lateral malleolus or communication of the joint with the peroneal tendon sheaths. Arthrography was assessed in 61 cases of recurrent lateral sprains of the ankle more than 2 weeks after acute injury; 38 were considered as positive. Twenty-five patients had operative evaluation, with four false negative and one false positive results. Small recesses adjacent to the lateral malleolus or opacification of the peroneal tendon sheaths are sequelae of an acute sprain with tear of the anterior talofibular and/or the calcaneofibular ligaments. Although false negative results occur, arthrography is useful in the preoperative assessment of chronic ankle instability. (orig.)

  15. Injured lateral ankle ligaments: technique and assessment of MRI

    International Nuclear Information System (INIS)

    56 patients with the clinical diagnosis of sprained ankles were investigated. Evaluation of the anterior (AFTL) and posterior fibulotalar ligament (PFTL) was performed with the foot in dorsiflexion (20 ) and of the fibulo calcanear ligament (FCL) in plantarflexion (45 ). Axial T1w-SE and T2w-TSE images were obtained. Full-length visualisation of ligmaments in one slice and the extent of injury were evaluated. 12 ankle injuries were confirmed by operation. With MRI full-length visualisation of lateral ankle ligaments was possible in 86%. A partial/complete rupture of the AFTL was noticed in 33/64% and of the FCI in 29/39%, and of the PFTL in 27/5%. Sensitivity/specificity of MRI when compared to surgery was 100/100% for injuries of the AFTL, 64/100% for the FCL, and 33/78% for the PFTL. (orig./MG)

  16. Examination of the sprained ankle: Anterior drawer test or arthrography?

    International Nuclear Information System (INIS)

    The accuracy of the anterior drawer test for the diagnosis of recent lateral ligament tears in the ankle was evaluated in a series of 192 patients using surgical or arthrographic findings for reference. Considerable overlapping of results was obtained in ankles with and without ligament tear. Twenty-eight per cent of the anterior talofibular ligament tears, and 38% of the combined anterior talofibular and calcaneofibular tears were not detected, and single and combined tears could not be differentiated. It is concluded that the anterior drawer test is too unreliable as a basis for any decision regarding surgical treatment of a recent sprain. Therefore, arthrography is recommended as the method of choice in such cases of recent ankle sprain, where the need of surgery has to be supported by X-ray analysis. (orig.)

  17. Arthrography of the ankle joint in chronic instability

    Energy Technology Data Exchange (ETDEWEB)

    Dory, M.A.

    1986-05-01

    Papers on arthrography of injuries of the lateral ligaments of the ankle relate mainly to recent distortion of the joint. Arthrography performed at a later stage after injury generally is considered useless. In fact, changes in chronic instability are observed; they are subtle and consist either of small recesses adjacent to the lateral malleolus or communication of the joint with the peroneal tendon sheaths. Arthrography was assessed in 61 cases of recurrent lateral sprains of the ankle more than 2 weeks after acute injury; 38 were considered as positive. Twenty-five patients had operative evaluation, with four false negative and one false positive results. Small recesses adjacent to the lateral malleolus or opacification of the peroneal tendon sheaths are sequelae of an acute sprain with tear of the anterior talofibular and/or the calcaneofibular ligaments. Although false negative results occur, arthrography is useful in the preoperative assessment of chronic ankle instability.

  18. Examination of the sprained ankle: Anterior drawer test or arthrography

    Energy Technology Data Exchange (ETDEWEB)

    Laehde, S.; Putkonen, M.; Puranen, J.; Raatikainen, T.

    1988-11-01

    The accuracy of the anterior drawer test for the diagnosis of recent lateral ligament tears in the ankle was evaluated in a series of 192 patients using surgical or arthrographic findings for reference. Considerable overlapping of results was obtained in ankles with and without ligament tear. Twenty-eight per cent of the anterior talofibular ligament tears, and 38% of the combined anterior talofibular and calcaneofibular tears were not detected, and single and combined tears could not be differentiated. It is concluded that the anterior drawer test is too unreliable as a basis for any decision regarding surgical treatment of a recent sprain. Therefore, arthrography is recommended as the method of choice in such cases of recent ankle sprain, where the need of surgery has to be supported by X-ray analysis.

  19. Diagnosis, treatment and prevention of ankle sprains : an evidence-based clinical guideline

    NARCIS (Netherlands)

    Kerkhoffs, Gino M.; van den Bekerom, Michel; Elders, Leon A. M.; van Beek, Peter A.; Hullegie, Wim A. M.; Bloemers, Guus M. F. M.; de Heus, Elly M.; Loogman, Masja C. M.; Rosenbrand, Kitty C. J. G. M.; Kuipers, Ton; Hoogstraten, J. W. A. P.; Dekker, Rienk; ten Duis, Henk-Jan; van Dijk, C. Niek; van Tulder, Maurits W.; van der Wees, Philip J.; de Bie, Rob A.

    2012-01-01

    Ankle injuries are a huge medical and socioeconomic problem. Many people have a traumatic injury of the ankle, most of which are a result of sports. Total costs of treatment and work absenteeism due to ankle injuries are high. The prevention of recurrences can result in large savings on medical cost

  20. Diagnosis, treatment and prevention of ankle sprains: an evidence-based clinical guideline.

    NARCIS (Netherlands)

    Kerkhoffs, G.M.; Bekerom, M. van den; Elders, L.A.; Beek, P.A. van; Hullegie, W.A.; Bloemers, G.M.; Heus, E.M. de; Loogman, M.C.; Rosenbrand, K.C.; Kuipers, T.; Hoogstraten, J.W.; Dekker, R.; Duis, H.J. Ten; Dijk, C.N. van; Tulder, M.W. van; Wees, P.J. van der; Bie, R.A. de

    2012-01-01

    Ankle injuries are a huge medical and socioeconomic problem. Many people have a traumatic injury of the ankle, most of which are a result of sports. Total costs of treatment and work absenteeism due to ankle injuries are high. The prevention of recurrences can result in large savings on medical cost

  1. Role of External Torque and Toroidal Momentum Transport in the Dynamics of Heat Transport in Internal Transport Barriers

    International Nuclear Information System (INIS)

    Full text: We study the coupling of intrinsic rotation and toroidal momentum transport to the dynamics of internal transport barriers (ITB). In particular, we 1. Elucidate the role of external torque in ITB formation and ion temperature de-stiffening 2. Analyze the interplay between intrinsic rotation and ITB dynamics. 3. Characterize the heat transport in steady state ITB plasmas. First, we find an external torque can either facilitate or hamper bifurcation in heat flux driven plasmas depending on its sign relative to the direction of intrinsic torque. The ratio between the radially integrated momentum density to power input is shown to be a key control parameter governing the characteristics of bifurcation. Second, we find that intrinsic rotation is closely coupled to ITB dynamics via dynamic change of Reynolds stress. In particular, we show that the excitation of parallel shear flow instability causes a Reynolds stress change and drives a momentum redistribution, which significantly influences ITB dynamics. Finally, we show that highly non-diffusive transport processes prevail in ITB plasmas (depending on the degree of turbulence suppression) from a statistical analysis of heat transport in steady state ITBs obtained from a long time flux-driven gyrofluid simulations. (author)

  2. Deltoid ligament in acute ankle injury: MR imaging analysis

    International Nuclear Information System (INIS)

    To identify the pattern of deltoid ligament injury after acute ankle injury and the relationship between ankle fracture and deltoid ligament tear by magnetic resonance imaging (MRI). Thirty-six patients (32 male, and 4 female; mean age, 29.8 years) with acute deltoid ligament injury who had undergone MRI participated in this study. The deltoid ligament was classified as having 3 superficial and 2 deep components. An image analysis included the integrity and tear site of the deltoid ligament, and other associated injuries. Association between ankle fracture and deltoid ligament tear was assessed using Fisher's exact test (P < 0.05). Of the 36 patients, 21 (58.3 %) had tears in the superficial and deep deltoid ligaments, 6 (16.7 %) in the superficial ligaments only, and 4 (11.1 %) in the deep ligaments only. The most common tear site of the three components of the superficial deltoid and deep anterior tibiotalar ligaments was their proximal attachments (94 % and 91.7 % respectively), and that of the deep posterior tibiotalar ligament (pTTL) was its distal attachment (82.6 %). The common associated injuries were ankle fracture (63.9 %), syndesmosis tear (55.6 %), and lateral collateral ligament complex tear (44.4 %). All the components of the deltoid ligament were frequently torn in patients with ankle fractures (tibionavicular ligament, P = 0.009). The observed injury pattern of the deltoid ligament was complex and frequently associated with concomitant ankle pathology. The most common tear site of the superficial deltoid ligament was the medial malleolar attachment, whereas that of the deep pTTL was near its medial talar insertion. (orig.)

  3. Acute paediatric ankle trauma: MRI versus plain radiography

    International Nuclear Information System (INIS)

    Objective: To evaluate the diagnosis of acute physeal ankle fractures on plain radiographs using MRI as the gold standard. Methods: Sixty consecutive children, 29 with a clinical diagnosis of lateral ligament injury and 31 with physeal ankle fractures, were examined using both radiographs and MRI in the acute period. The imaging data were reviewed by three ''masked'' radiologists. The fracture diagnosis and Slater-Harris classification of radiographs were compared with findings on MRI. Results: Plain radiography produced five of 28 (18%) false negative and 12 of 92 (13%) false positive fracture diagnoses compared with MRI. Six of the 12 false positive fractures were due to a misclassification of lateral ligament disruption as SH1 fractures. Altogether a difference was found in 21% of cases in either the diagnosis or the classification of the fractures according to Salter- Harris. All bone bruises in the distal tibia and fibula and 64% of bone bruises in the talus were seen in association with lateral ligament injuries. Talar bone bruises in association with fractures occurred on the same side as the malleolar fracture; talar bone bruises in association with lateral ligament disruption were seen in different locations. The errors identified on radiographs by MRI did not affect the management of the injury. Conclusions: The incidence of false negative ankle fractures in plain radiographs was small and no complex ankle fractures were missed on radiographs. The total extent of complex fractures was, however, not always obvious on radiographs. In an unselected series of relatively mild ankle injuries, we were unable to show a single case where the treatment or prognosis based on plain radiography should have been significantly altered after having done a routine MRI examination. Plain radiography is still the diagnostic cornerstone of paediatric ankle injuries. (orig.)

  4. Deltoid ligament in acute ankle injury: MR imaging analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Min Sun; Choi, Yun Sun; Kim, Yun Jung; Jung, Yoon Young [Eulji University, Department of Radiology, Eulji Hospital, Seoul (Korea, Republic of); Kim, Jin Su; Young, Ki Won [Eulji University, Department of Orthopedic Surgery, Eulji Hospital, Seoul (Korea, Republic of)

    2014-05-15

    To identify the pattern of deltoid ligament injury after acute ankle injury and the relationship between ankle fracture and deltoid ligament tear by magnetic resonance imaging (MRI). Thirty-six patients (32 male, and 4 female; mean age, 29.8 years) with acute deltoid ligament injury who had undergone MRI participated in this study. The deltoid ligament was classified as having 3 superficial and 2 deep components. An image analysis included the integrity and tear site of the deltoid ligament, and other associated injuries. Association between ankle fracture and deltoid ligament tear was assessed using Fisher's exact test (P < 0.05). Of the 36 patients, 21 (58.3 %) had tears in the superficial and deep deltoid ligaments, 6 (16.7 %) in the superficial ligaments only, and 4 (11.1 %) in the deep ligaments only. The most common tear site of the three components of the superficial deltoid and deep anterior tibiotalar ligaments was their proximal attachments (94 % and 91.7 % respectively), and that of the deep posterior tibiotalar ligament (pTTL) was its distal attachment (82.6 %). The common associated injuries were ankle fracture (63.9 %), syndesmosis tear (55.6 %), and lateral collateral ligament complex tear (44.4 %). All the components of the deltoid ligament were frequently torn in patients with ankle fractures (tibionavicular ligament, P = 0.009). The observed injury pattern of the deltoid ligament was complex and frequently associated with concomitant ankle pathology. The most common tear site of the superficial deltoid ligament was the medial malleolar attachment, whereas that of the deep pTTL was near its medial talar insertion. (orig.)

  5. Acute paediatric ankle trauma: MRI versus plain radiography

    Energy Technology Data Exchange (ETDEWEB)

    Lohman, M. [Helsinki Univ. Central Hospital (Finland). Dept. of Radiology; Radiological Dept., Helsinki University Central Hospital (Finland); Kivisaari, A.; Kivisaari, L. [Helsinki Univ. Central Hospital (Finland). Dept. of Radiology; Kallio, P.; Puntila, J. [Dept. of Paediatric Surgery, Hospital for Children and Adolescents, Helsinki Univ. Central Hospital, Helsinki (Finland); Vehmas, T. [Finnish Institute of Occupational Health, Helsinki (Finland)

    2001-09-01

    Objective: To evaluate the diagnosis of acute physeal ankle fractures on plain radiographs using MRI as the gold standard. Methods: Sixty consecutive children, 29 with a clinical diagnosis of lateral ligament injury and 31 with physeal ankle fractures, were examined using both radiographs and MRI in the acute period. The imaging data were reviewed by three ''masked'' radiologists. The fracture diagnosis and Slater-Harris classification of radiographs were compared with findings on MRI. Results: Plain radiography produced five of 28 (18%) false negative and 12 of 92 (13%) false positive fracture diagnoses compared with MRI. Six of the 12 false positive fractures were due to a misclassification of lateral ligament disruption as SH1 fractures. Altogether a difference was found in 21% of cases in either the diagnosis or the classification of the fractures according to Salter- Harris. All bone bruises in the distal tibia and fibula and 64% of bone bruises in the talus were seen in association with lateral ligament injuries. Talar bone bruises in association with fractures occurred on the same side as the malleolar fracture; talar bone bruises in association with lateral ligament disruption were seen in different locations. The errors identified on radiographs by MRI did not affect the management of the injury. Conclusions: The incidence of false negative ankle fractures in plain radiographs was small and no complex ankle fractures were missed on radiographs. The total extent of complex fractures was, however, not always obvious on radiographs. In an unselected series of relatively mild ankle injuries, we were unable to show a single case where the treatment or prognosis based on plain radiography should have been significantly altered after having done a routine MRI examination. Plain radiography is still the diagnostic cornerstone of paediatric ankle injuries. (orig.)

  6. The effect of knee joint angle on torque control.

    Science.gov (United States)

    Sosnoff, Jacob J; Voudrie, Stefani J; Ebersole, Kyle T

    2010-01-01

    The purpose of the author's investigation was to examine the effect of knee joint angle on torque control of the quadriceps muscle group. In all, 12 healthy adults produced maximal voluntary contractions and submaximal torque (15, 30, and 45% MVC [maximal voluntary contraction]) at leg flexion angles of 15 degrees , 30 degrees , 60 degrees , and 90 degrees below the horizontal plane. As expected, MVC values changed with respect to joint angle with maximum torque output being greatest at 60 degrees and least at 15 degrees . During the submaximal tasks, participants appropriately scaled their torque output to the required targets. Absolute variability (i.e., standard deviation) of torque output was greatest at 60 degrees and 90 degrees knee flexion. However, relative variability as indexed by coefficient of variation (CV) decreased as joint angle increased, with the greatest CV occurring at 15 degrees . These results are congruent with the hypothesis that joint angle influences the control of torque. PMID:19906637

  7. COMMUTATION TIME ESTIMATOR FOR PM BLDC MOTOR TORQUE SIGNATURE ENHANCEMENT

    Directory of Open Access Journals (Sweden)

    WAEL A. SALAH

    2014-12-01

    Full Text Available This paper presents the development of the commutation time estimator (CTE for PM BLDC motor drives. The proposed scheme is aimed to enhance motor output torque by minimizing the generated torque ripples. The torque ripples originating from commutation instances cause spikes and dips in the motor output torque. The motor output torque could be enhanced by mitigating the phase current mismatch rate during phase current commutation period. This rate could be almost matched by introducing the commutation time estimator (CTE in order to control the rate of the energized phase current to be matched with the de-energized phase rate. Results obtained have validated and verified the proposed CTE effectiveness with a 50% average reduction of the generated torque ripples in PM BLDC motor.

  8. Imaging of soft tissue lesions of the foot and ankle.

    Science.gov (United States)

    Bancroft, Laura W; Peterson, Jeffrey J; Kransdorf, Mark J

    2008-11-01

    Differential diagnosis of soft tissue lesions of the foot can be narrowed with imaging. The cystic nature of ganglia, synovial cysts, and bursitis can be confirmed with MR imaging or sonography. Location and signal characteristics of noncystic lesions can suggest Morton's neuroma, giant cell tumor of tendon sheath, and plantar fibromatosis. Synovial-based lesions of the foot and ankle can be differentiated based on presence or absence of mineralization, lesion density, signal intensity, and enhancement pattern. Knowledge of the incidence of specific neoplasms of the foot and ankle based on patient age aids in providing a limited differential diagnosis. PMID:19038615

  9. Ankle sprain and postural sway in basketball players.

    Science.gov (United States)

    Leanderson, J; Wykman, A; Eriksson, E

    1993-01-01

    The present study compares postural ankle stability between previously injured basketball players, uninjured players and a control/group. Postural sway was recorded and analysed by stabilometry using a specially designed computer-assisted forceplate. Recordings were obtained for 60 s on each foot. The stabilometric results in the players with no previous injuries did not differ from those in the controls. Players with a previously injured ankle differed significantly from the control group. These players had a larger mean postural sway and used a larger sway area. PMID:8536030

  10. Imaging of Soft Tissue Lesions of the Foot and Ankle

    Directory of Open Access Journals (Sweden)

    Seyed Hassan Mostafavi

    2010-05-01

    Full Text Available Differential diagnosis of soft tissue lesions of the foot may be narrowed with imaging. The cystic nature of ganglia, synovial cysts, and bursitis can be confirmed with MR imaging or sonography. Location and signal characteristics of noncystic lesions may suggest Morton's neuroma, giant cell tumor of the tendon sheath and plantar fibromatosis. Synovial-based lesions of the foot and ankle can be differentiated based on presence or absence of mineralization, lesion density, signal intensity, and the enhancement pattern. Knowledge of the incidence of specific neoplasms of the foot and ankle based on patient age aids in providing a limited differential diagnosis

  11. A historical perspective on ankle ligaments reconstructive surgery.

    Science.gov (United States)

    Di Matteo, Berardo; Tarabella, Vittorio; Filardo, Giuseppe; Tomba, Patrizia; Viganò, Anna; Marcacci, Maurilio; Zaffagnini, Stefano

    2016-04-01

    Ankle sprains are by far the most common injuries treated by sport medicine physicians. Treatment is mainly conservative, but in some cases surgical intervention is required. The aim of the present manuscript is to give an insight into the origins and developments of ankle ligaments reconstructive surgery, underlining the fundamental steps that marked the transition from a mere conservative approach to surgical treatment options. In this historical note, the most illustrious figures who contributed to this particular field of orthopaedic practice are also acknowledged. Level of evidence V. PMID:26718639

  12. Functional bandage for ankle sprains. Recommendations for nursing

    Directory of Open Access Journals (Sweden)

    Mª Isabel Arcos Cirauqui

    2011-11-01

    Full Text Available Three quarters of ankle injuries are diagnosed as sprains. For the most part sprains are caused by a forced inversion movement with involvement of the lateral collateral ligament (LCL. One of the recommended guidelines is immobilization by taping. The aim of this article is to unify the recommendations for nursing, on taping in the treatment of ankle sprains. The methodology used was a literature review, analyzing the information found in books and journals in hospital libraries and nursing databases on the Internet. The main results are a set of guidelines for the most accurate and therapeutic taping.

  13. Quasi-steady plasma acceleration.

    Science.gov (United States)

    Jahn, R. G.; Von Jaskowsky, W. F.; Clark, K. E.

    1973-01-01

    A coaxial plasma accelerator driven by protracted pulses of current in the range of 10,000 to 100,000 A and synchronized mass flows from 1.0 to 36 g/sec argon attains, after some tens of microseconds, a stable magnetoplasmadynamic acceleration mode. This 'quasi-steady' discharge form is characterized by constant terminal voltage and current, a diffuse, fixed current distribution within the discharge, and a steady plasma efflux at velocities of approximately 20 km/sec. Measured potential distributions reveal that the bulk of the arc voltage gradient, exclusive of the electrode falls, occurs within two diameters of the cathode, and is normal to it. The anode fall voltage varies inversely with local current density, implying substantially lower anode losses at higher power arc operation. Spectroscopic, potential, and velocity measurements indicate the existence of a characteristic mass flow rate for a given current, below which arc operation becomes erratic.

  14. Steady-state eternal inflation

    International Nuclear Information System (INIS)

    Since the advent of inflation, several theorems have been proven suggesting that although inflation can (and generically does) continue eternally into the future, it cannot be extended eternally into the past to create a 'steady-state' model with no initial time. Here we provide a construction that circumvents these theorems and allows a self-consistent, geodesically complete, and physically sensible steady-state eternally inflating universe, based on the flat slicing of de Sitter space. This construction could be used as the background spacetime for creation events that form big-bang-like regions, and hence could form the basis for a cosmology that is compatible with observations and yet which avoids an initial singularity or beginning of time

  15. DIRECT TORQUE CONTROL FOR INDUCTION MOTOR USING INTELLIGENT TECHNIQUES

    Directory of Open Access Journals (Sweden)

    R.Toufouti

    2007-09-01

    Full Text Available In this paper, we propose two approach intelligent techniques of improvement of Direct Torque Control (DTC of Induction motor such as fuzzy logic (FL and artificial neural network (ANN, applied in switching select voltage vector .The comparison with conventional direct torque control (DTC, show that the use of the DTC_FL and DTC_ANN, reduced the torque, stator flux, and current ripples. The validity of the proposed methods is confirmed by the simulative results.

  16. DIRECT TORQUE CONTROL FOR INDUCTION MOTOR USING INTELLIGENT TECHNIQUES

    OpenAIRE

    R. Toufouti; S.Meziane; Benalla, H.

    2007-01-01

    In this paper, we propose two approach intelligent techniques of improvement of Direct Torque Control (DTC) of Induction motor such as fuzzy logic (FL) and artificial neural network (ANN), applied in switching select voltage vector .The comparison with conventional direct torque control (DTC), show that the use of the DTC_FL and DTC_ANN, reduced the torque, stator flux, and current ripples. The validity of the proposed methods is confirmed by the simulative results.

  17. Speed Sensorless Variable Structure Torque Control of Induction Motor

    OpenAIRE

    Jezernik, Karel; Şabanoviç, Asif; SABANOVIC, Asif

    2008-01-01

    Abstract— Induction motor speed sensorless torque control, which allows operation at low and zero speed, optimizing both torque response and efficiency, is proposed. The control is quite different than the conventional field-oriented or direct torque control. A new discontinuous stator current FPGA based controller and rotor flux observer based on continuous sliding mode and Lyapunov theory are developed. A smooth transition into the field weakening region and the full ut...

  18. Torque Maximizing and Flux Weakening Control of Synchronous Machines

    OpenAIRE

    Khan, Waqar

    2016-01-01

    In this thesis, the torque maximizing and field weakening control strategies for synchronous machines with magnetically anisotropic structure such as synchronous reluctance machines (SyRMs) and interior permanent magnet machines (IPMs) are studied. In order to obtain maximum torque using minimum stator current, the maximum torque per ampere (MTPA) control strategy is employed below the base speeds. The MTPA control is limited by the maximum available voltage of the motor. Therefore, field wea...

  19. Spin-Torque Driven Magnetization Dynamics: Micromagnetic Modelling

    OpenAIRE

    Berkov, D. V.; Miltat, J.

    2007-01-01

    In this paper we present an overview of recent progress made in the understanding of the spin-torque induced magnetization dynamics in nanodevices using mesoscopic micromagnetic simulations. We first specify how a spin-torque term may be added to the usual Landau-Lifshitz-Gilbert equation of magnetization motion and detail its physical meaning. After a brief description of spin-torque driven dynamics in the macrospin approximation, we discuss the validity of this approximation for various exp...

  20. Steady state neutral beam injector

    International Nuclear Information System (INIS)

    Learning from operational reliability of neutral beam injectors in particular and various heating schemes including RF in general on TFTR, JET, JT-60, it has become clear that neutral beam injectors may find a greater role assigned to them for maintaining the plasma in steady state devices under construction. Many technological solutions, integrated in the present day generation of injectors have given rise to capability of producing multimegawatt power at many tens of kV. They have already operated for integrated time >105 S without deterioration in the performance. However, a new generation of injectors for steady state devices have to address to some basic issues. They stem from material erosion under particle bombardment, heat transfer > 10 MW/m2, frequent regeneration of cryopanels, inertial power supplies, data acquisition and control of large volume of data. Some of these engineering issues have been addressed to in the proposed neutral beam injector for SST-1 at our institute; the remaining shall have to wait for the inputs of the database generated from the actual experience with steady state injectors. (author)