Sample records for sub-sea system actuation

  1. Sub-sea engineering course (offshore submarine systems); Subsea engineering course (systemes sous - marins offshore)

    Energy Technology Data Exchange (ETDEWEB)

    Preedy, J.; Chasserot, J.L. [Azur Offshore Ltd (United Kingdom)


    This document gathers 770 pages of information about offshore submarine systems and 16 pages of appendix (glossary). Content: course introduction, introduction to sub-sea engineering, review of diver-assisted sub-sea production systems, sub-sea completion and christmas trees, basis of offshore exploration and production, sub-sea manifolds and templates, new technology for sub-sea production, flow-lines and pipelines, design of risers (flexible, towers, steel catenary and rigid), reliability, risks and human factors, review of deep-water (diver-less) sub-sea production systems, sub-sea control systems and chemical injection, case study - Malampaya Field Tie Back (Philippines), sub-sea systems inspection, maintenance and repair, cost evaluations, field assessments and cost data base, sub-sea well operations and flow assurance.

  2. Hydrate prevention in petroleum production sub sea system

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Paula L.F.; Rocha, Humberto A.R. [Universidade Estacio de Sa (UNESA), Rio de Janeiro, RJ (Brazil); Rodrigues, Antonio P. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)


    In spite of the merits of the several hydrate prevention techniques used nowadays, such as: chemical product injection for inhibition and use of thick thermal insulate lines; hydrates per times happen and they are responsible for considerable production losses. Depressurization techniques can be used so much for prevention as in the remediation. Some hydrate removal techniques need a rig or vessel, resources not readily available and with high cost, reason that limits such techniques just for remediation and not for prevention. In the present work it is proposed and described an innovative depressurization system, remote and resident, for hydrate prevention and removal, applicable as for individual sub sea wells as for grouped wells by manifold. Based on low cost jet pumps, without movable parts and with a high reliability, this technique allows hydrate prevention or remediation in a fast and remote way, operated from the production unit. The power fluid line and fluid return line can be integrated in the same umbilical or annulus line structure, without significant increase in the construction costs and installation. It is not necessary to wait for expensive resource mobilization, sometimes not available quickly, such as: vessels or rigs. It still reduces the chemical product consumption and permits to depressurized stopped lines. Other additional advantage, depressurization procedure can be used in the well starting, removing fluid until riser emptying. (author)

  3. Tendon Driven Finger Actuation System (United States)

    Ihrke, Chris A. (Inventor); Reich, David M. (Inventor); Bridgwater, Lyndon (Inventor); Linn, Douglas Martin (Inventor); Askew, Scott R. (Inventor); Diftler, Myron A. (Inventor); Platt, Robert (Inventor); Hargrave, Brian (Inventor); Valvo, Michael C. (Inventor); Abdallah, Muhammad E. (Inventor); hide


    A humanoid robot includes a robotic hand having at least one finger. An actuation system for the robotic finger includes an actuator assembly which is supported by the robot and is spaced apart from the finger. A tendon extends from the actuator assembly to the at least one finger and ends in a tendon terminator. The actuator assembly is operable to actuate the tendon to move the tendon terminator and, thus, the finger.

  4. Microelectromechanical Systems Actuator Based Reconfigurable Printed Antenna (United States)

    Simons, Rainee N. (Inventor)


    A polarization reconfigurable patch antenna is disclosed. The antenna includes a feed element, a patch antenna element electrically connected to the feed element, and at least one microelectromechanical systems (MEMS) actuator, with a partial connection to the patch antenna element along an edge of the patch antenna element. The polarization of the antenna can be switched between circular polarization and linear polarization through action of the at least one MEMS actuator.

  5. Dielectric Elastomer Actuated Systems and Methods (United States)

    Dubowsky, Steven (Inventor); Hafez, Moustapha (Inventor); Lichter, Matthew (Inventor); Weiss, Peter (Inventor); Wingert, Andreas (Inventor)


    The system of the present invention includes an actuator having at least two electrodes, an elastomeric dielectric film disposed between the two electrodes, and a frame attached to the elastomeric dielectric film. The frame provides a linear actuation force characteristic over a displacement range. The displacement range is preferably the stroke of the actuator. The displacement range can be about 5 mm and greater. Further, the frame can include a plurality of configurations, for example, at least a rigid members coupled to a flexible member wherein the frame provides an elastic restoring force. In preferred embodiments, the rigid member can be, but is not limited to, curved beams, parallel beams, rods and plates. In a preferred embodiment the actuator can further include a passive element disposed between two flexible members such as, for example, links to tune a stiffness characteristic of the actuator. The passive element can be a bi-stable element. Further, the actuator can include a plurality of layers of the elastomeric dielectric film integrated into the frame. The elastomeric film can be made of different materials such as, for example, acrylic, silicone and latex.

  6. A porous actuator for an Isfet-based coulometric sensor-actuator system

    NARCIS (Netherlands)

    Luo, J.; Luo, J.; Olthuis, Wouter; Bergveld, Piet; van der Linden, W.E.; Bos, M.


    The previously developed prototype ISFET (ion-sensitive field effect transistor)-based coulometric sensor-actuator system suffers from delay in response due to the nonzero distance between the sensor and actuator. The authors describe a novel configuration of a sensor-actuator device which employs a

  7. Converter fed sub sea motor drives

    Energy Technology Data Exchange (ETDEWEB)

    Raad, R.O.


    Minor offshore gas and oil resources located 20-50 km from existing installations may often be commercially exploited only by use of complete sub sea solutions. This thesis deals with analyses of a sub sea adjustable speed electric motor which is fed by a frequency converter via a long cable (up to 50 km) between the converter and the motor. The author develops a general model for analysing such motor drive systems with the objective of verifying the feasibility of specific applications and of specifying the requirements on the system components. The simulation model is used to identify the critical frequency ranges in which the converter must not generate significant harmonics, to verify the start-up strategy chosen, and to verify the stability with potential disturbances applied to the system. Simulation models are developed for both transient and steady state analyses. They are accurate up to 5 kHz and can incorporate the frequency dependency of the motor and cable parameters. Ideal thyristors and diodes are used. The models are implemented in existing simulation tools. Most of the results relate to a base case with a 670 kW squirrel cage motor fed from a 30 km long cable, but cases with 3 MW rating or with 50 km cable have also been analyzed and found to be feasible. Each specific application must be separately studied. Results of simulation calculations are presented and conclusions given. 53 refs., 124 figs., 23 tabs.

  8. Bioinspired pressure actuated adhesive system

    NARCIS (Netherlands)

    Paretkar, D.R.; Kamperman, M.M.G.; Schneider, A.S.; Martina, D.; Creton, C.; Arzt, E.


    We developed a dry synthetic adhesive system inspired by gecko feet adhesion that can switch reversibly from adhesion to non-adhesion with applied pressure as external stimulus. Micropatterned polydimethylsiloxane (PDMS) surfaces with pillars of 30 µm length and 10 µm diameter were fabricated using

  9. Actuator development for the Instrument Pointing System (IPS) (United States)

    Suttner, K.


    The mechanisms of the instrument pointing system (IPS) are described. Particular emphasis is placed on the actuators which are necessary for operating the IPS. The actuators are described as follows: (1) two linear actuators that clamp the gimbals down during ascent and descent; (2) two linear actuators that attach the payload to the IPS during the mission, and release it into the payload clamps; (3) one rotational actuator that opens and closes the payload clamps; and (4) three identical drive units that represent the three orthogonal gimbal axes and are the prime movers for pointing. Design features, manufacturing problems, test performance, and results are presented.

  10. A remote and autonomous continuous monitoring ultrasonic system for flood detection in sub-sea members of offshore steel oil rigs

    Energy Technology Data Exchange (ETDEWEB)

    Mijarez-Castro, Rito


    This thesis presents a novel and autonomous continuous monitoring system for flood detection in the hollow sub-sea members of offshore steel oil rigs. The technique offers an alternative to underwater nondestructive testing methods based on ultrasound and x-rays, which have been used to detect the presence of seawater in these applications, often with divers or remote operating vehicles. The research consists of theoretical and experimental work necessary for the development of an integral system that can be used in new fixed offshore oil rig designs. The system employs a single piezoelectric transducer which can be permanently attached to the inner wall of every sub-sea structure and which is powered by a normally inert seawater battery. Upon activation, the sensor transmits ultrasonic chirp or tone encoded pulses in the range of 21 k Hz to 42 k Hz, to a monitoring system at deck level for decoding and identifying flooded members. Two approaches to the system were considered during the investigation, depending on the communication channel exploited. These were based on either using the seawater as a propagation medium or using the steel structure as a wave-guide. A system based on theoretical models was built and field experiments were conducted using a purpose built jointed steel pipe structure, 7 m in length, 0.5 m in diameter and 16 mm in thickness. This structure was flooded by complete immersion in seawater. Results obtained using water as communication medium and a frequency in the order of 38 k Hz yielded an attenuation figure of 0.4 d B m{sub -}1 over 100 m, since losses were predominantly geometric. In contrast, using the tubular structure as a wave-guide and axis symmetric guided waves as the excitation, a gross attenuation figure of 1.3 d B m{sub -}1 was attained. In the straight parts of the structure, the attenuation ranged from 0.3 d B m{sub -} 1 to 0.6 d B m{sub -}1. The modes most likely to have been excited within the structure were L(0,5) - L(0

  11. Microelectromechanical systems integrating molecular spin crossover actuators

    Energy Technology Data Exchange (ETDEWEB)

    Manrique-Juarez, Maria D. [LCC, CNRS and Université de Toulouse, UPS, INP, F-31077 Toulouse (France); LAAS, CNRS and Université de Toulouse, INSA, UPS, F-31077 Toulouse (France); Rat, Sylvain; Salmon, Lionel; Molnár, Gábor; Bousseksou, Azzedine, E-mail:, E-mail: [LCC, CNRS and Université de Toulouse, UPS, INP, F-31077 Toulouse (France); Mathieu, Fabrice; Saya, Daisuke; Séguy, Isabelle; Leïchlé, Thierry; Nicu, Liviu, E-mail:, E-mail: [LAAS, CNRS and Université de Toulouse, INSA, UPS, F-31077 Toulouse (France)


    Silicon MEMS cantilevers coated with a 200 nm thin layer of the molecular spin crossover complex [Fe(H{sub 2}B(pz){sub 2}){sub 2}(phen)] (H{sub 2}B(pz){sub 2} = dihydrobis(pyrazolyl)borate and phen = 1,10-phenantroline) were actuated using an external magnetic field and their resonance frequency was tracked by means of integrated piezoresistive detection. The light-induced spin-state switching of the molecules from the ground low spin to the metastable high spin state at 10 K led to a well-reproducible shift of the cantilever's resonance frequency (Δf{sub r} = −0.52 Hz). Control experiments at different temperatures using coated as well as uncoated devices along with simple calculations support the assignment of this effect to the spin transition. This latter translates into changes in mechanical behavior of the cantilever due to the strong spin-state/lattice coupling. A guideline for the optimization of device parameters is proposed so as to efficiently harness molecular scale movements for large-scale mechanical work, thus paving the road for nanoelectromechanical systems (NEMS) actuators based on molecular materials.

  12. Overview of Actuated Arm Support Systems and Their Applications

    Directory of Open Access Journals (Sweden)

    E.A. Lomonova


    Full Text Available Arm support systems provide support throughout daily tasks, training or in an industrial environment. During the last decades a large diversity of actuated arm support systems have been developed. To analyze the actuation principles in these systems, an overview of actuated arm support systems is provided. This overview visualizes the current trends on research and development of these support systems and distinguishes three categories. These categories depend mainly on the functional status of the user environment, which defines the specifications. Therefore, the actuated arm support systems are classified according to their user environment, namely: ambulatory, rehabilitation and industrial. Furthermore, three main actuation principles and three mechanical construction principles have been identified.

  13. A system look at electromechanical actuation for primary flight control

    NARCIS (Netherlands)

    Lomonova, E.A.


    An overview is presented of the emergence of the ALL Electric flight control system (FCS) or power-by-wire (PBW) concept. The concept of fly-by-power refers to the actuator using electrical rather than hydraulic power. The development of the primary flight control Electromechanical Actuators (EMAs)

  14. Stability and stabilization of linear systems with saturating actuators

    CERN Document Server

    Tarbouriech, Sophie; Gomes da Silva Jr, João Manoel; Queinnec, Isabelle


    Gives the reader an in-depth understanding of the phenomena caused by the more-or-less ubiquitous problem of actuator saturation. Proposes methods and algorithms designed to avoid, manage or overcome the effects of actuator saturation. Uses a state-space approach to ensure local and global stability of the systems considered. Compilation of fifteen years' worth of research results.

  15. Size dependent droplet actuation in digital microfluidic systems (United States)

    Bhattacharjee, Biddut; Najjaran, Homayoun


    Digital microfluidic systems (DMFS) manipulate liquid droplets with volumes in submicroliter range in two dimensional arrays of cells. Among possible droplet actuation mechanisms, Electrowetting-on-dielectric (EWOD) actuation has been found to be most feasible and advantageous because of low power consumption, ease of signal generation and basic device fabrication. In EWOD based DMFS, droplets are actuated by applying an electric field and thus increasing the wettability on one side of the droplet. In this paper, we show that the EWOD actuation of a droplet can be modeled as a closed loop system having unity feedback of position. Electrode, dielectric and droplet are modeled as a capacitor with variable area as the droplet, considered as a conductor, moves over the dielectric layer. The EWOD force depends on the rate of change of droplet area over the actuated electrode, which in turn depends on the direction of motion and the position of the droplet between the actuated and previous electrode. Thus, EWOD actuation intrinsically utilizes the droplet position to generate sufficient force to accelerate the droplet. When the droplet approaches the final position, the magnitude of force reduces automatically so the droplet decelerates. In case the droplet has sufficient momentum to exceed the final position, the EWOD force, according to the model, will act on the opposite side of the droplet in order to bring it back to the desired position. The dynamic response has been characterized using the proposed model for different droplet sizes, actuation voltages, dielectric thicknesses and electrode sizes.

  16. System and Method for Tensioning a Robotically Actuated Tendon (United States)

    Reiland, Matthew J. (Inventor); Diftler, Myron A. (Inventor)


    A tendon tensioning system includes a tendon having a proximal end and a distal end, an actuator, and a motor controller. The actuator may include a drive screw and a motor, and may be coupled with the proximal end of the tendon and configured to apply a tension through the tendon in response to an electrical current. The motor controller may be electrically coupled with the actuator, and configured to provide an electrical current having a first amplitude to the actuator until a stall tension is achieved through the tendon; provide a pulse current to the actuator following the achievement of the stall tension, where the amplitude of the pulse current is greater than the first amplitude, and return the motor to a steady state holding current following the conclusion of the pulse current.

  17. Hydraulically-actuated operating system for an electric circuit breaker (United States)

    Barkan, Philip; Imam, Imdad


    This hydraulically-actuated operating system comprises a cylinder, a piston movable therein in an opening direction to open a circuit breaker, and an accumulator for supplying pressurized liquid to a piston-actuating space within the cylinder. A normally-closed valve between the accumulator and the actuating space is openable to allow pressurized liquid from the accumulator to flow through the valve into the actuating space to drive the piston in an opening direction. A vent is located hydraulically between the actuating space and the valve for affording communication between said actuating space and a low pressure region. Flow control means is provided for restricting leakage through said vent to a rate that prevents said leakage from substantially detracting from the development of pressure within said actuatng space during the period from initial opening of the valve to the time when said piston has moved through most of its opening stroke. Following such period and while the valve is still open, said flow control means allows effective leakage through said vent. The accumulator has a limited capacity that results in the pressure within said actuating space decaying promptly to a low value as a result of effective leakage through said vent after the piston has moved through a circuit-breaker opening stroke and while the valve is in its open state. Means is provided for resetting the valve to its closed state in response to said pressure decay in the actuating space.

  18. A jellyfish-like swimming mini-robot actuated by an electromagnetic actuation system (United States)

    Ko, Youngho; Na, Sungyoung; Lee, Youngwoo; Cha, Kyoungrae; Ko, Seong Young; Park, Jongoh; Park, Sukho


    Among the various kinds of actuations for biomimetic robots, the electromagnetic actuation (EMA) method has been regarded as the one with the most potential. This paper proposes a jellyfish-like swimming mini-robot actuated by an EMA system in three-dimensional (3D) space. The jellyfish-like mini-robot has four flexible fins, each of which is equipped with a permanent magnet for electromagnetic actuation; the robot’s body is 17 mm long and 0.5 mm thick. Our EMA system was able to generate a uniform magnetic field in a desired direction in 3D space, which could bend the fins of the jellyfish-like mini-robot. Therefore, a cyclic change in the uniform magnetic field, in the EMA system, would synchronize the fluctuation of the fins and could generate a propulsion force for the robot, in the desired direction. In order to maximize the propulsion force of the jellyfish-like mini-robot, the waveform and frequency of the input current in the EMA system are optimized. Consequently, our jellyfish-like mini-robot was able to generate maximum propulsion force when a square waveform input current (13 A magnitude and 10 Hz frequency) was applied to the EMA system. Finally, the jellyfish-like mini-robot with the EMA system was able to perform various 3D swimming motions.

  19. On reliable control system designs. Ph.D. Thesis; [actuators (United States)

    Birdwell, J. D.


    A mathematical model for use in the design of reliable multivariable control systems is discussed with special emphasis on actuator failures and necessary actuator redundancy levels. The model consists of a linear time invariant discrete time dynamical system. Configuration changes in the system dynamics are governed by a Markov chain that includes transition probabilities from one configuration state to another. The performance index is a standard quadratic cost functional, over an infinite time interval. The actual system configuration can be deduced with a one step delay. The calculation of the optimal control law requires the solution of a set of highly coupled Riccati-like matrix difference equations. Results can be used for off-line studies relating the open loop dynamics, required performance, actuator mean time to failure, and functional or identical actuator redundancy, with and without feedback gain reconfiguration strategies.

  20. Adaptive Non-linear Control of Hydraulic Actuator Systems

    DEFF Research Database (Denmark)

    Hansen, Poul Erik; Conrad, Finn


    Presentation of two new developed adaptive non-liner controllers for hydraulic actuator systems to give stable operation and improved performance.Results from the IMCIA project supported by the Danish Technical Research Council (STVF).......Presentation of two new developed adaptive non-liner controllers for hydraulic actuator systems to give stable operation and improved performance.Results from the IMCIA project supported by the Danish Technical Research Council (STVF)....

  1. Optimal Sensor and Actuator Location for Unstable Systems

    DEFF Research Database (Denmark)

    Shaker, Hamid Reza; Tahavori, Maryamsadat


    on the processes. Dually the problem of placing actuators on the processes is equally important. In this paper, the problem of determining optimal sensor and actuator locations for the linear systems is addressed. The problem of the sensor locations is viewed as the problem of maximizing the output energy...... generated by a given state and for the actuator locations is viewed as the problem of minimizing the input energy required to reach a given state. Such design problems occur in many applications, and therefore have been studied extensively. Unfortunately, the results in this context, which have been...

  2. Benefits and Challenges of Over-Actuated Excitation Systems

    Directory of Open Access Journals (Sweden)

    Norman Fitz-Coy


    Full Text Available This paper provides a comprehensive discussion on the benefits and technical challenges of controlling over-determined and over-actuated excitation systems ranging from 1-DOF to 6-DOF. The primary challenges of over-actuated systems result from the physical constraints imposed when the number of exciters exceeds the number of mechanical degree-of-freedom. This issue is less critical for electro-dynamic exciters which tend to be more compliant than servo-hydraulic exciters. To facilitate the technical challenges discussion, generalized methods for determining the drive output commands and the actuator input transform is presented. To further provide insights into the problem, over-actuated 1-DOF and 6-DOF examples are provided. Results are presented to support the discussions.

  3. Nonlinear feedback control of dual-stage actuator system (United States)

    Liu, Chuan; Liu, Yang; Li, Xing; Chen, Xing-lin


    The wafer stage of lithography is a dual-stage actuator (DSA) system. An nm-level positioning precision is required by using macro movement of long-stroke linear motor and high-precision micro movement of short-stroke voice coil motor, while the platform is moving in high-speed. This brief presents a nonlinear control method for dual-stage actuator systems to track a step command input fast and accurately. To further reduce the settling time, we design the long-stroke actuator controller with the control law of proximate time optimal control (PTOC) to yield a closed-loop system with a small damping ratio for a fast rise time and certain allowable overshoot. Moreover, for the purpose of reducing the overshoot caused by the long-stroke actuator as the system output approaches the target location, a composite nonlinear feedback (CNF) control law is designed for the short-stroke actuator to yield a closed-loop system with a large damping ratio. The linear extended state observer (LESO) was designed to estimate the unknown velocity and compensate the disturbance of servo systems, thus static error could be effectively decreased. We applied this proposed control method to an actual DSA positioning system, which consists of a linear motor and a voice coil motor. Experimental results show that our approach can improve the dynamic performance and the anti-jamming capability of the system, enhance the control precision.

  4. Stabilization of Neutral Systems with Saturating Actuators

    Directory of Open Access Journals (Sweden)

    F. El Haoussi


    to determine stabilizing state-feedback controllers with large domain of attraction, expressed as linear matrix inequalities, readily implementable using available numerical tools and with tuning parameters that make possible to select the most adequate solution. These conditions are derived by using a Lyapunov-Krasovskii functional on the vertices of the polytopic description of the actuator saturations. Numerical examples demonstrate the effectiveness of the proposed technique.

  5. Design control system of telescope force actuators based on WLAN (United States)

    Shuai, Xiaoying; Zhang, Zhenchao


    With the development of the technology of autocontrol, telescope, computer, network and communication, the control system of the modern large and extra lager telescope become more and more complicated, especially application of active optics. Large telescope based on active optics maybe contain enormous force actuators. This is a challenge to traditional control system based on wired networks, which result in difficult-to-manage, occupy signification space and lack of system flexibility. Wireless network can resolve these disadvantages of wired network. Presented control system of telescope force actuators based on WLAN (WFCS), designed the control system framework of WFCS. To improve the performance of real-time, we developed software of force actuators control system in Linux. Finally, this paper discussed improvement of WFCS real-time, conceived maybe improvement in the future.

  6. Two-stage actuation system using DC motors and piezoelectric actuators for controllable industrial and automotive brakes and clutches (United States)

    Neelakantan, Vijay A.; Washington, Gregory N.; Bucknor, Norman K.


    High bandwidth actuation systems that are capable of simultaneously producing relatively large forces and displacements are required for use in automobiles and other industrial applications. Conventional hydraulic actuation mechanisms used in automotive brakes and clutches are complex, inefficient and have poor control robustness. These lead to reduced fuel economy, controllability issues and other disadvantages. This paper involves the design, development, testing and control of a two-stage hybrid actuation mechanism by combining classical actuators like DC motors and advanced smart material actuators like piezoelectric actuators. The paper also discusses the development of a robust control methodology using the Internal Model Control (IMC) principle and emphasizes the robustness property of this control methodology by comparing and studying simulation and experimental results.

  7. Electrical breakdown detection system for dielectric elastomer actuators (United States)

    Ghilardi, Michele; Busfield, James J. C.; Carpi, Federico


    Electrical breakdown of dielectric elastomer actuators (DEAs) is an issue that has to be carefully addressed when designing systems based on this novel technology. Indeed, in some systems electrical breakdown might have serious consequences, not only in terms of interruption of the desired function but also in terms of safety of the overall system (e.g. overheating and even burning). The risk for electrical breakdown often cannot be completely avoided by simply reducing the driving voltages, either because completely safe voltages might not generate sufficient actuation or because internal or external factors might change some properties of the actuator whilst in operation (for example the aging or fatigue of the material, or an externally imposed deformation decreasing the distance between the compliant electrodes). So, there is the clear need for reliable, simple and cost-effective detection systems that are able to acknowledge the occurrence of a breakdown event, making DEA-based devices able to monitor their status and become safer and "selfaware". Here a simple solution for a portable detection system is reported that is based on a voltage-divider configuration that detects the voltage drop at the DEA terminals and assesses the occurrence of breakdown via a microcontroller (Beaglebone Black single-board computer) combined with a real-time, ultra-low-latency processing unit (Bela cape an open-source embedded platform developed at Queen Mary University of London). The system was used to both generate the control signal that drives the actuator and constantly monitor the functionality of the actuator, detecting any breakdown event and discontinuing the supplied voltage accordingly, so as to obtain a safer controlled actuation. This paper presents preliminary tests of the detection system in different scenarios in order to assess its reliability.

  8. Properties of polypyrrole polyvinilsulfate films for dual actuator sensing systems (United States)

    Pascual, Victor H.; Otero, Toribio F.; Schumacher, Johanna


    One of the challenges of modern science is the development of actuators able to sense working conditions while actuation, mimicking the way in which biological organs work. Actuation of those organs includes nervous (electric) pulses dense reactive gels, chemical reactions exchange of ions and solvent. For that purpose, conducting polymers are being widely studied. In this work the properties of self-supported films of the polypyrrole:polyvinilsulfate (PPy/PVS) blend polymer were assessed. X-ray photoelectron spectroscopy (XPS) studies show how during reduction / oxidation the polymer exchanges cations when immersed in a NaClO4 aqueous solution, revealing free positive charges in the electrolytic solution as the driving agents leading to the swelling/shrinking of the polymer. Eventually it is the phenomenon responsible of the actuation of the polymeric motors. Submitting the system to consecutive potential sweeps shows the reaction is really sensing the scan rate used in each cycle revealing that while actuating the system is actually sensing the electrochemical working conditions.

  9. Design of Transputer Controllers for Hydraulic Actuator Systems

    DEFF Research Database (Denmark)

    Conrad, Finn


    The paper deals with how transputers can be applied for fast controllers for hydraulic actuator systems. A general transputer-based control systems including a data acquisition transputer subsystem is presented. An application case: development of a mechatronic test facility with a fast hydraulic...

  10. Actuator prototype system by voice commands using free software

    Directory of Open Access Journals (Sweden)

    Jaime Andrango


    Full Text Available This prototype system is a software application that through the use of techniques of digital signal processing, extracts information from the user's speech, which is then used to manage the on/off actuator on a peripheral computer when vowels are pronounced. The method applies spectral differences. The application uses the parallel port as actuator, with the information recorded in the memory address 378H. This prototype was developed using free software tools for its versatility and dynamism, and to allow other researchers to base on it for further studies.

  11. Pneumatic Actuation of a 2-Link Robotic System

    African Journals Online (AJOL)



    Oct 16, 2014 ... nanorobotics, are still in the testing phase but they demand precision. The investigation of a 2-link pneumatic robotic system, using robotic and electric actuators, will be made. For the sake of representation, the prototype will be made of available materials in the market to fulfil its requirements. An insight.

  12. Modeling and Synthesis Methods for Retrofit Design of Submarine Actuation Systems. Energy Storage for Electric Actuators (United States)


    sternplane v - sway w - heave u - surge X Y Z y z x Figure 2: Coordinate frame definitions of submarine vehicular dynamics. 2.1 Six Degree of Freedom...where Mν̇ is the total inertial matrix, C(ν) is the Coriolis/centripetal matrix, D(ν) is the total damping matrix, g(η) are the buoyancy and weight...Natick, MA. Retrofit Design of Submarine Actuation Systems Page 7 q - pitch w - heave u - surge δs Msp Figure 3: Hydrodynamic moment unit definition

  13. Analysis of helicopter flight dynamics through modeling and simulation of primary flight control actuation system (United States)

    Nelson, Hunter Barton

    A simplified second-order transfer function actuator model used in most flight dynamics applications cannot easily capture the effects of different actuator parameters. The present work integrates a nonlinear actuator model into a nonlinear state space rotorcraft model to determine the effect of actuator parameters on key flight dynamics. The completed actuator model was integrated with a swashplate kinematics where step responses were generated over a range of key hydraulic parameters. The actuator-swashplate system was then introduced into a nonlinear state space rotorcraft simulation where flight dynamics quantities such as bandwidth and phase delay analyzed. Frequency sweeps were simulated for unique actuator configurations using the coupled nonlinear actuator-rotorcraft system. The software package CIFER was used for system identification and compared directly to the linearized models. As the actuator became rate saturated, the effects on bandwidth and phase delay were apparent on the predicted handling qualities specifications.

  14. 30 CFR 75.1103-6 - Automatic fire sensors; actuation of fire suppression systems. (United States)


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic fire sensors; actuation of fire... Protection § 75.1103-6 Automatic fire sensors; actuation of fire suppression systems. Point-type heat sensors or automatic fire sensor and warning device systems may be used to actuate deluge-type water systems...

  15. Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction System (United States)

    Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor)


    A novel full piezoelectric multilayer stacked hybrid actuation/transduction system. The system demonstrates significantly-enhanced electromechanical performance by utilizing the cooperative contributions of the electromechanical responses of multilayer stacked negative and positive strain components. Both experimental and theoretical studies indicate that for this system, the displacement is over three times that of a same-sized conventional flextensional actuator/transducer. The system consists of at least 2 layers which include electromechanically active components. The layers are arranged such that when electric power is applied, one layer contracts in a transverse direction while the second layer expands in a transverse direction which is perpendicular to the transverse direction of the first layer. An alternate embodiment includes a third layer. In this embodiment, the outer two layers contract in parallel transverse directions while the middle layer expands in a transverse direction which is perpendicular to the transverse direction of the outer layers.

  16. Conducting IPN actuator/sensor for biomimetic vibrissa system (United States)

    Festin, N.; Plesse, C.; Pirim, P.; Chevrot, C.; Vidal, F.


    Electroactive polymers, or EAPs, are polymers that exhibit a change in size or shape when stimulated by an electric field. The most common applications of this type of material are in actuators and sensors. One promising technology is the elaboration of electronic conducting polymers based actuators with Interpenetrating Polymer Networks (IPNs) architecture. Their many advantageous properties as low working voltage, light weight and high lifetime make them very attractive for various applications including robotics. Conducting IPNs were fabricated by oxidative polymerization of 3,4-ethylenedioxythiophene within a flexible Solid Polymer Electrolytes (SPE) combining poly(ethylene oxide) and Nitrile Butadiene Rubber. SPE mechanical properties and ionic conductivities in the presence of 1-ethyl-3- methylimidazolium bis-(trifluoromethylsulfonyl)-imide (EMITFSI) have been characterized. The presence of the elastomer within the SPE greatly improves the actuator performances. The free strain as well as the blocking force was characterized as a function of the actuator length. The sensing properties of those conducting IPNs allow their integration into a biomimetic perception prototype: a system mimicking the tactile perception of rat vibrissae.

  17. Control of a perturbed under-actuated mechanical system

    KAUST Repository

    Zayane, Chadia


    In this work, the trajectory tracking problem for an under-actuated mechanical system in presence of unknown input disturbances is addressed. The studied inertia wheel inverted pendulum falls in the class of non minimum phase systems. The proposed high order sliding mode control architecture including a controller and differentiator allows to track accurately the predefined trajectory and to stabilize the internal dynamics. The robustness of the proposed approach is illustrated through different perturbation and output noise configurations.

  18. Pneumatic Muscle Actuated Compliant Gripper Systems

    Directory of Open Access Journals (Sweden)

    Deaconescu Andrea


    Full Text Available The paper presents the stages of developing new, light, eco-friendly and bionic gripper systems. Gripping is achieved by means of original, self adaptive, bio-inspired systems, with a pneumatic muscle as motion generator. The method underlying the development of these new gripping systems is based on the creation of concepts by analogy, an instrument aimed at widening the inspiration horizon in designing by using models from nature.

  19. Experimental analysis of chaos in under actuated electromechanical systems

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Hernandez, H. G. [Universidad la Salle, Mexico, D.F. (Mexico); Alvarez Gallegos, Jaime [Instituto Politecnico Nacional (Mexico); Alvarez Gallegos Joaquin [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Ensenada, Baja California (Mexico)


    An under actuated system is a kind of non-autonomous robotic system in which there are more links than actuators. The complexity of the dynamical behavior of these systems allows a wide variety of steady-state responses. The reconstruction of attractors based on time series obtained from measurements of one of the variables of a two-link, planar, under actuated robot called Pendubot, is developed. Time-delay coordinates, average mutual information, and percentage of false nearest neighbors' methods are used to reconstruct the invariant sets. It is shown that, under the action of a periodic torque, the Pendubot can display a variety of steady-state dynamics, including strange attractors. [Spanish] Un sistema electromecanico subactuado es un tipo de sistema robotico no autonomo que cuenta con mas eslabones que actuadores. La complejidad del comportamiento dinamico de estos sistemas permite una gran variedad de respuestas en estado estacionario. En este trabajo se desarrolla la reconstruccion de atractores basada en series de tiempo obtenidas a partir de mediciones de una de las variables de un robot planar de dos grados de libertad subactuado llamado Pendubot. A fin de reconstruir los conjuntos invariantes, se utilizan tecnica como retraso de coordenadas, promedio de informacion mutua y porcentaje de falsos vecinos cercanos. Se muestra que bajo la accion de un torque periodico, el Pendubot puede desplegar una variedad de comportamientos dinamicos en estado estacionario incluyendo atractores extranos.

  20. Delayed system control in presence of actuator saturation

    Directory of Open Access Journals (Sweden)

    A. Mahjoub


    Full Text Available The paper is introducing a new design method for systems’ controllers with input delay and actuator saturations and focuses on how to force the system output to track a reference input not necessarily saturation-compatible. We propose a new norm based on the way we quantify tracking performance as a function of saturation errors found using the same norm. The newly defined norm is related to signal average power making possible to account for most common reference signals e.g. step, periodic. It is formally shown that, whatever the reference shape and amplitude, the achievable tracking quality is determined by a well defined reference tracking mismatch error. This latter depends on the reference rate and its compatibility with the actuator saturation constraint. In fact, asymptotic output-reference tracking is achieved in the presence of constraint-compatible step-like references.

  1. Design of a Series Elastic- and Bowdencable-based actuation system for use as torque-=actuator in exoskeleton-type training

    NARCIS (Netherlands)

    Veneman, J.F.; Ekkelenkamp, R.; Kruidhof, R.; van der Helm, F.C.T.; van der Kooij, Herman


    Common actuators have important drawbacks for use in an exoskeleton type of rehabilitation (training) robot. Either the actuators are heavy, complex or poor torque sources. A new actuation system is proposed and tested that combines a lightweight joint and a simple structure with adequate torque

  2. Towards Autonomous Control of Hydraulic Actuator Systems

    DEFF Research Database (Denmark)

    Hansen, Poul Erik; Conrad, Finn


    Presentation of new developed control algorithms to increase autonomy and intelligence of hydraulic control systems. A refinement of relaytuning method is used to determine the control parameters of a lag/lead controller and a poleplacement controller. Further, a fail-safe function is developed...... to hinder surges and mechanical fractures. Experimental results verify the performance of the controllers....

  3. Integrating Sensory/Actuation Systems in Agricultural Vehicles (United States)

    Emmi, Luis; Gonzalez-de-Soto, Mariano; Pajares, Gonzalo; Gonzalez-de-Santos, Pablo


    In recent years, there have been major advances in the development of new and more powerful perception systems for agriculture, such as computer-vision and global positioning systems. Due to these advances, the automation of agricultural tasks has received an important stimulus, especially in the area of selective weed control where high precision is essential for the proper use of resources and the implementation of more efficient treatments. Such autonomous agricultural systems incorporate and integrate perception systems for acquiring information from the environment, decision-making systems for interpreting and analyzing such information, and actuation systems that are responsible for performing the agricultural operations. These systems consist of different sensors, actuators, and computers that work synchronously in a specific architecture for the intended purpose. The main contribution of this paper is the selection, arrangement, integration, and synchronization of these systems to form a whole autonomous vehicle for agricultural applications. This type of vehicle has attracted growing interest, not only for researchers but also for manufacturers and farmers. The experimental results demonstrate the success and performance of the integrated system in guidance and weed control tasks in a maize field, indicating its utility and efficiency. The whole system is sufficiently flexible for use in other agricultural tasks with little effort and is another important contribution in the field of autonomous agricultural vehicles. PMID:24577525

  4. Integrating Sensory/Actuation Systems in Agricultural Vehicles

    Directory of Open Access Journals (Sweden)

    Luis Emmi


    Full Text Available In recent years, there have been major advances in the development of new and more powerful perception systems for agriculture, such as computer-vision and global positioning systems. Due to these advances, the automation of agricultural tasks has received an important stimulus, especially in the area of selective weed control where high precision is essential for the proper use of resources and the implementation of more efficient treatments. Such autonomous agricultural systems incorporate and integrate perception systems for acquiring information from the environment, decision-making systems for interpreting and analyzing such information, and actuation systems that are responsible for performing the agricultural operations. These systems consist of different sensors, actuators, and computers that work synchronously in a specific architecture for the intended purpose. The main contribution of this paper is the selection, arrangement, integration, and synchronization of these systems to form a whole autonomous vehicle for agricultural applications. This type of vehicle has attracted growing interest, not only for researchers but also for manufacturers and farmers. The experimental results demonstrate the success and performance of the integrated system in guidance and weed control tasks in a maize field, indicating its utility and efficiency. The whole system is sufficiently flexible for use in other agricultural tasks with little effort and is another important contribution in the field of autonomous agricultural vehicles.

  5. A Systems Engineering Approach to Electro-Mechanical Actuator Diagnostic and Prognostic Development (United States)

    National Aeronautics and Space Administration — The authors have formulated a Comprehensive Systems Engineering approach to Electro-Mechanical Actuator (EMA) Prognostics and Health Management (PHM) system...


    Directory of Open Access Journals (Sweden)

    V. N. Akimov


    Full Text Available One of the important problems of the designing of maneuverable unmanned aerial vehicles (UAV is to ensure aeroelastic stability with automatic control system (ACS. One of the possible types of aeroelastic instability of UAV with ACS is loss of stability in the system "surface control – actuator".  A nonlinear model for the study of the stability of the system "surface control – actuator" is designed for solving problems of joint design of airframe and ACS with the requirements of aeroelasticity. The electric actuator is currently the most widely used on highly maneuverable UAV. The wide bandwidth and the availability of frequency characteristic lifts are typical for the modern electric actuator. This exacerbates the problem of providing aeroelastic stability of the UAV with ACS, including the problem of ensuring the stability of the system "surface control – actuator". In proposed model the surface control, performing bending-torsion oscillations in aerodynamic flow, in fact, is the loading for the actuator. Experimental frequency characteristics of the isolated actuator, obtained for different levels of the control signal, are used for the mathematical description of the actuator, then, as dynamic hinge moment, which is determined by aeroelastic vibrations of the surface control in the air flow, is calculated. Investigation of the stability of the system "surface control – actuator" is carried out by frequency method using frequency characteristics of the open-loop system. The undeniable advantage of the proposed model is the simplicity of obtaining the transfer functions of the isolated actuator. The experiment by its definition is a standard method of determining frequency characteristics of the actuator in contrast to time-consuming experiments for determining the dynamic stiffness of the actuator (with the surface control or the transfer function of the actuator using electromechanical simulation of aeroelastic loading of the

  7. Installation of deep water sub-sea equipment

    Energy Technology Data Exchange (ETDEWEB)

    Pollack, Jack; Demian, Nabil [SBM-IMODCO Inc., Houston, TX (UNited States)


    Offshore oil developments are being planned in water depths exceeding 2000 m. Lowering and positioning large, heavy sub sea hardware, using conventional methods, presents new technical challenges in these ultra deep waters. In 3000 m a safe lift using conventional steel cables will require more capacity to support the cable self weight than the static payload. Adding dynamic loads caused by the motions of the surface vessel can quickly cause the safe capacity of the wire to be exceeded. Synthetic ropes now exist to greatly reduce the lowering line weight. The lower stiffness of these synthetic ropes aggravate the dynamic line tensions due to vessel motions and relatively little is known about the interaction of these ropes on the winches and sheaves required for pay-out and haul-in of these lines under dynamic load. Usage of conventional winches would damage the synthetic rope and risk the hardware being deployed. Reliable and economic installation systems that can operate from existing installation vessels are considered vital for ultra deep-water oil development. The paper describes a Deep Water Sub-Sea Hardware Deployment system consisting of a buoy with variable, pressure-balanced buoyancy, which is used to offset most of the payload weight as it is lowered. The buoyant capacity is controlled by air pumped into the tank from the surface vessel through a reinforced hose. The buoy and payload motion are isolated from the deployment line surface dynamics using a simple passive heave compensator mounted between the buoy and the bottom of the deployment rope. The system components, functionality and dynamic behavior are presented in the paper. (author)

  8. Prognostic Health-Management System Development for Electromechanical Actuators (United States)

    National Aeronautics and Space Administration — Electro-mechanical actuators (EMAs) have been gaining increased acceptance as safety-critical actuation devices in the next generation of aircraft and spacecraft....

  9. Modelling of coulometric sensor-actuator systems based on ISFETs with a porous actuator covering the gate

    NARCIS (Netherlands)

    Luo, J.; Luo, J.; Olthuis, Wouter; Bergveld, Piet; Bos, M.; van der Linden, W.E.


    The ion-selective field effect transistor (ISFET)-based coulometric sensor¿actuator systems have found applications in acid¿base titration and in the construction of a low-drift carbon dioxide and a pH-static enzyme sensor. In this paper a brief review is given of the previously developed

  10. Electromagnetic variable degrees of freedom actuator systems and methods (United States)

    Montesanti, Richard C [Pleasanton, CA; Trumper, David L [Plaistow, NH; Kirtley, Jr., James L.


    The present invention provides a variable reluctance actuator system and method that can be adapted for simultaneous rotation and translation of a moving element by applying a normal-direction magnetic flux on the moving element. In a beneficial example arrangement, the moving element includes a swing arm that carries a cutting tool at a set radius from an axis of rotation so as to produce a rotary fast tool servo that provides a tool motion in a direction substantially parallel to the surface-normal of a workpiece at the point of contact between the cutting tool and workpiece. An actuator rotates a swing arm such that a cutting tool moves toward and away from a mounted rotating workpiece in a controlled manner in order to machine the workpiece. Position sensors provide rotation and displacement information for a swing arm to a control system. A control system commands and coordinates motion of the fast tool servo with the motion of a spindle, rotating table, cross-feed slide, and in feed slide of a precision lathe.

  11. Integration of Flex Nozzle System and Electro Hydraulic Actuators to Solid Rocket Motors (United States)

    Nayani, Kishore Nath; Bajaj, Dinesh Kumar


    A rocket motor assembly comprised of solid rocket motor and flex nozzle system. Integration of flex nozzle system and hydraulic actuators to the solid rocket motors are done after transportation to the required place where integration occurred. The flex nozzle system is integrated to the rocket motor in horizontal condition and the electro hydraulic actuators are assembled to the flex nozzle systems. The electro hydraulic actuators are connected to the hydraulic power pack to operate the actuators. The nozzle-motor critical interface are insulation diametrical compression, inhibition resin-28, insulation facial compression, shaft seal `O' ring compression and face seal `O' ring compression.

  12. Full Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction Systems (United States)

    Su, Ji; Jiang, Xiaoning; Zu, Tian-Bing


    The Stacked HYBATS (Hybrid Actuation/Transduction system) demonstrates significantly enhanced electromechanical performance by using the cooperative contributions of the electromechanical responses of multilayer, stacked negative strain components and positive strain components. Both experimental and theoretical studies indicate that, for Stacked HYBATS, the displacement is over three times that of a same-sized conventional flextensional actuator/transducer. The coupled resonance mode between positive strain and negative strain components of Stacked HYBATS is much stronger than the resonance of a single element actuation only when the effective lengths of the two kinds of elements match each other. Compared with the previously invented hybrid actuation system (HYBAS), the multilayer Stacked HYBATS can be designed to provide high mechanical load capability, low voltage driving, and a highly effective piezoelectric constant. The negative strain component will contract, and the positive strain component will expand in the length directions when an electric field is applied on the device. The interaction between the two elements makes an enhanced motion along the Z direction for Stacked-HYBATS. In order to dominate the dynamic length of Stacked-HYBATS by the negative strain component, the area of the cross-section for the negative strain component will be much larger than the total cross-section areas of the two positive strain components. The transverse strain is negative and longitudinal strain positive in inorganic materials, such as ceramics/single crystals. Different piezoelectric multilayer stack configurations can make a piezoelectric ceramic/single-crystal multilayer stack exhibit negative strain or positive strain at a certain direction without increasing the applied voltage. The difference of this innovation from the HYBAS is that all the elements can be made from one-of-a-kind materials. Stacked HYBATS can provide an extremely effective piezoelectric

  13. A motionless actuation system for magnetic shape memory devices (United States)

    Armstrong, Andrew; Finn, Kevin; Hobza, Anthony; Lindquist, Paul; Rafla, Nader; Müllner, Peter


    Ni-Mn-Ga is a Magnetic Shape Memory (MSM) alloy that changes shape in response to a variable magnetic field. We can intentionally manipulate the shape of the material to function as an actuator, and the material can thus replace complicated small electromechanical systems. In previous work, a very simple and precise solid-state micropump was developed, but a mechanical rotation was required to translate the position of the magnetic field. This mechanical rotation defeats the purpose of the motionless solid-state device. Here we present a solid-state electromagnetic driver to linearly progress the position of the applied magnetic field and the associated shrinkage. The generated magnetic field was focused at either of two pole pieces, providing a mechanism for moving the localized shrinkage in the MSM element. We confirmed that our driver has sufficient strength to actuate the MSM element using optical microscopy. We validated the whole design by comparing results obtained with finite element analysis with the experimentally measured flux density. This drive system serves as a possible replacement to the mechanical rotation of the magnetic field by using a multi-pole electromagnet that sweeps the magnetic field across the MSM micropump element, solid-state switching the current to each pole piece in the multi-pole electromagnet.

  14. Optimal Sensors and Actuators Placement for Large-Scale Unstable Systems via Restricted Genetic Algorithm

    DEFF Research Database (Denmark)

    Seyyed Sakha, Masoud; Shaker, Hamid Reza


    One of the fundamental problems in control systems engineering is the problem of sensors and actuators placement. Decisions in this context, play a key role in the success of control process. The methods developed for optimal placement of the sensors and actuators are known to be computationally...... for sensors and actuator placement. Unlike the other counterparts, the method not only supports unstable systems but also reduces the computational complexity significantly. The method is illustrated by numerical examples....

  15. Iridium oxide as actuator material for the ISFET-based sensor-actuator system

    NARCIS (Netherlands)

    Olthuis, Wouter; Bomer, Johan G.; Bergveld, Piet; van der Linden, W.E.; Bos, M.; Bos, M.


    Acid or base concentrations can be determined by performing an acid-base titration with Coulometrically generated OH- or H+ ions at a noble-metal actuator electrode in close proximity to the pH-sensitive gate of an ISFET. The ISFET is used as the indicator electrode to detect the equivalence point

  16. Storage Reliability of Missile Materiel Program. Missile Hydraulic and Pneumatic Systems Actuator Analysis (United States)


    RELIABILITY OF / MISSILE MATERIEL PROGRANI MISSILE gYDRAULIC AND NEUMATIC SYSTEMS ACTUATOR ANALYSIS .. 7 ." Joe C. Mitchell Approved by: Donald R. Earles...amplifier. 3-5 - M77777,77-7WT7 SECTION 4 ACTUATOR CLASSIFICATION Actuators have been classified in accordance with the mechanism and type. Figure 4-1...definition of the data already on hdrnd. More detailed identification of those units classified only by their generic names should be attempted. A more

  17. Decentralized stabilization of linear time invariant systems subject to actuator saturation

    NARCIS (Netherlands)

    Stoorvogel, Antonie Arij; Saberi, Ali; Deliu, Ciprian; Deliu, C.; Sannuti, Peddapullaiah; Tarbouriech, S.; Garcia, G.; Glattfelder, A.H.


    We are concerned here with the stabilization of a linear time invariant system subject to actuator saturation via decentralized control while using linear time invariant dynamic controllers. When there exists no actuator saturation, i.e. when we consider just linear time invariant systems, it is

  18. Dielectric Elastomer Actuators for Soft Wave-Handling Systems. (United States)

    Wang, Tao; Zhang, Jinhua; Hong, Jun; Wang, Michael Yu


    This article presents a soft handling system inspired by the principle of the natural wave (named Wave-Handling system) aiming to offer a soft solution to delicately transport and sort fragile items such as fruits, vegetables, biological tissues in food, and biological industries. The system consists of an array of hydrostatically coupled dielectric elastomer actuators (HCDEAs). Due to the electrostriction property of dielectric elastomers, the handling system can be controlled by electric voltage rather than the cumbersome pneumatic system. To study the working performance of the Wave-Handling system and how the performance can be improved, the basic properties of HCDEA are investigated through experiments. We find that the HCDEA exhibits some delay and hysteretic characteristics when activated by periodic voltage and the characteristics are influenced by the frequency and external force also. All this will affect the performance of the Wave-Handling system. However, the electric control, simple structure, light weight, and low cost of the soft handling system show great potential to move from laboratory to practical application. As a proof of design concept, a simply made prototype of the handling system is controlled to generate a parallel moving wave to manipulate a ball. Based on the experimental results, the improvements and future work are discussed and we believe this work will provide inspiration for soft robotic engineering.

  19. Constant force actuator for gravitational wave detector's seismic attenuation systems (SAS)

    Energy Technology Data Exchange (ETDEWEB)

    Wang Chenyang E-mail:; Tariq, Hareem; DeSalvo, Riccardo E-mail:; Iida, Yukiyoshi; Marka, Szabolcs; Nishi, Yuhiko; Sannibale, Virginio; Takamori, Akiteru


    We have designed, tested and implemented a UHV-compatible, low-noise, non-contacting force actuator for DC positioning and inertial damping of the rigid body resonances of the Seismic Attenuation System (SAS) designed for the TAMA Gravitational Wave Interferometer. The actuator fully satisfies the stringent zero-force-gradient requirements that are necessary to prevent re-injecting seismic noise into the SAS chain. The actuator's closed magnetic field design makes for particularly low power requirements, and low susceptibility to external perturbations. The actuator retains enough strength to absorb seismic perturbations even during small earthquakes.

  20. Magnetically-induced solid-phase microextraction fiber actuation system for quantitative headspace and liquid sampling (United States)

    Harvey, Chris; Carter, Jerry; Chambers, David M.


    A magnetically-induced SPME fiber actuation system includes a SPME fiber holder and a SPME fiber holder actuator, for holding and magnetically actuating a SPME fiber assembly. The SPME fiber holder has a plunger with a magnetic material to which the SPME fiber assembly is connected, and the magnetic SPME fiber holder actuator has an elongated barrel with a loading chamber for receiving the SPME fiber assembly-connected SPME fiber holder, and an external magnet which induces axial motion of the magnetic material of the plunger to extend/retract the SPME fiber from/into the protective needle of the SPME fiber assembly.

  1. Shape memory system with integrated actuation using embedded particles (United States)

    Buckley, Patrick R [New York, NY; Maitland, Duncan J [Pleasant Hill, CA


    A shape memory material with integrated actuation using embedded particles. One embodiment provides a shape memory material apparatus comprising a shape memory material body and magnetic pieces in the shape memory material body. Another embodiment provides a method of actuating a device to perform an activity on a subject comprising the steps of positioning a shape memory material body in a desired position with regard to the subject, the shape memory material body capable of being formed in a specific primary shape, reformed into a secondary stable shape, and controllably actuated to recover the specific primary shape; including pieces in the shape memory material body; and actuating the shape memory material body using the pieces causing the shape memory material body to be controllably actuated to recover the specific primary shape and perform the activity on the subject.

  2. Investigation and Development of the Thermal Preparation System of the Trailbuilder Machinery Hydraulic Actuator (United States)

    Konev, V.; Polovnikov, E.; Krut, O.; Merdanov, Sh; Zakirzakov, G.


    It’s determined that the main part of trailbuilders operated in the North is the technology equipped by the hydraulic actuator. Further development of the northern territories will demand using of various means and ways machinery thermal preparation, and also the machinery of the northern fulfillment. On this basis problems in equipment operation are defined. One of the main is efficiency supplying of a hydraulic actuator. On the basis of the operating conditions’ analysis of trailbuilder hydraulic actuator operation it is determined, that under low negative temperatures the means of thermal preparation are necessary. The existing systems warm up only a hydraulic tank or warming up of the hydro equipment before the machinery operation is carried out under loading with intensive wears. Thus, with the purpose to raise the efficiency of thermal hydraulic actuator, operated far from stationary bases autonomous, energy saving, not expensive in creation and operation systems are necessary. In accordance with the analysis of means and ways of the thermal preparation of the hydraulic actuator and the thermal balance calculations of the (internal) combustion engine the system of the hydraulic actuator heating is offered and is being investigated. It contains a local hydraulic actuator warming up and the system of internal combustion engine heat utilization. Within research operation conditions of the local hydraulic actuator heating are viewed and determined, taking into account constructive changes to the local hydraulic actuator heating. Mathematical modelling of the heat technical process in the modernized hydraulic actuator is considered. As a result temperature changes of the heat-transfer and the hydraulic cylinder in time are determined. To check the theoretical researches and to define dependences on hydraulic actuator warming up, the experimental installation is made. It contains the measuring equipment, a small tank with the heat exchanger of the burnt gases

  3. Control Reconfiguration of LPV Systems Using Virtual Sensor and Virtual Actuator

    DEFF Research Database (Denmark)

    Tabatabaeipour, Seyed Mojtaba; Stoustrup, Jakob; Bak, Thomas


    In this paper, a fault tolerant control method for linear parameter varying (LPV) systems using a virtual actuator and a virtual sensor is proposed. The basic idea of the method is to insert a reconfiguration block, which consists of an LPV virtual actuator and an LPV virtual sensor, between the ...

  4. Fuzzy Adaptive Compensation Control of Uncertain Stochastic Nonlinear Systems With Actuator Failures and Input Hysteresis. (United States)

    Wang, Jianhui; Liu, Zhi; Chen, C L Philip; Zhang, Yun


    Hysteresis exists ubiquitously in physical actuators. Besides, actuator failures/faults may also occur in practice. Both effects would deteriorate the transient tracking performance, and even trigger instability. In this paper, we consider the problem of compensating for actuator failures and input hysteresis by proposing a fuzzy control scheme for stochastic nonlinear systems. Compared with the existing research on stochastic nonlinear uncertain systems, it is found that how to guarantee a prescribed transient tracking performance when taking into account actuator failures and hysteresis simultaneously also remains to be answered. Our proposed control scheme is designed on the basis of the fuzzy logic system and backstepping techniques for this purpose. It is proven that all the signals remain bounded and the tracking error is ensured to be within a preestablished bound with the failures of hysteretic actuator. Finally, simulations are provided to illustrate the effectiveness of the obtained theoretical results.

  5. Determination of buffer capacity by means of an ISFET-based coulometric sensor-actuator system with a gate-covering porous actuator

    NARCIS (Netherlands)

    Luo, J.; Luo, J.; Olthuis, Wouter; Bergveld, Piet; Bos, M.; van der Linden, W.E.


    In this paper we propose a dynamic way to measure the buffer capacity of an electrolyte by means of an ISFET-based coulometric sensor-actuator system whose gate is covered with a porous actuator. A theoterical model for this measurement is presented. Experiments are carried out in nitric and acetic

  6. Control of an electro-hydrostatic actuation system for the nose landing gear of an "all electric aircraft"


    Greissner, Carsten; Carl, Udo


    The EU research Project Power Optimised Aircraft (POA) investigates the approach to replace primary hydraulic supply by extended electric power systems towards a More or All Electric Aircraft. This contribution presents an electrically powered actuation system for nose landing gears using an EHA (electrohydrostatic actuator) approach. One motor pump unit supplies door and gear actuation as well as the steering system. Different control strategies for the individual actuators are introduced. T...

  7. NanoDrill: 1 Actuator Core Acquisition System Project (United States)

    National Aeronautics and Space Administration — We propose to design, build and test a 1 kg, single actuator, sample acquisition drill. The drill uses a novel method of core or powder acquisition. The core...

  8. System Compliant Actuation for Structural Engine Noise Remission Project (United States)

    National Aeronautics and Space Administration — The purpose of the research into ?Compliant Actuator? design will be to demonstrate to prototype level a low profile fully integrated control mechanism. This...

  9. Robotic Arm and Rover Actuator Systems for Mars Exploration (United States)

    Reid, L.; Brawn, D.; Noon, D.


    Missions such as the Sojourner Rover, the Robotic Arm for Mars Polar Lander, and the 2003 Mars Rover, Athena, use numerous actuators that must operate reliably in extreme environments for long periods of time.

  10. Demonstration of Vibrational Braille Code Display Using Large Displacement Micro-Electro-Mechanical Systems Actuators (United States)

    Watanabe, Junpei; Ishikawa, Hiroaki; Arouette, Xavier; Matsumoto, Yasuaki; Miki, Norihisa


    In this paper, we present a vibrational Braille code display with large-displacement micro-electro-mechanical systems (MEMS) actuator arrays. Tactile receptors are more sensitive to vibrational stimuli than to static ones. Therefore, when each cell of the Braille code vibrates at optimal frequencies, subjects can recognize the codes more efficiently. We fabricated a vibrational Braille code display that used actuators consisting of piezoelectric actuators and a hydraulic displacement amplification mechanism (HDAM) as cells. The HDAM that encapsulated incompressible liquids in microchambers with two flexible polymer membranes could amplify the displacement of the MEMS actuator. We investigated the voltage required for subjects to recognize Braille codes when each cell, i.e., the large-displacement MEMS actuator, vibrated at various frequencies. Lower voltages were required at vibration frequencies higher than 50 Hz than at vibration frequencies lower than 50 Hz, which verified that the proposed vibrational Braille code display is efficient by successfully exploiting the characteristics of human tactile receptors.

  11. Sub Sea Permafrost Climate Modeling - The fate of the East Siberian Arctic Shelf (United States)

    Rodehacke, Christian; Stendel, Martin; Marchenko, Sergey; Nicolsky, Dmitry; Christensen, Jens; Romanovsky, Vladimir


    Recent observations indicate that the East Siberian Arctic Shelf (ESAS) releases methane, which stems from shallow hydrate seabed reservoirs. The total amount of carbon within the ESAS is so large that release of only a small fraction, for example via taliks, which are columns of unfrozen sediment within the permafrost, could impact distinctly the global climate. Therefore it is crucial to simulate the future fate of ESAS' sub sea permafrost with regard to changing atmospheric and oceanic conditions. However only very few attempts to address the vulnerability of sub sea permafrost have been made, instead most studies have focused on the evolution of permafrost since the Late Pleistocene ocean transgression, starting 14000 years ago. In contrast to land permafrost modeling, any attempt to model the future fate of sub sea permafrost needs to consider several additional factors, in particular the dependence of freezing temperature on water depth and salt content and the differences in ground heat flux depending on the seabed properties. Also the amount of unfrozen water in the sediment needs to be taken into account. Using a system of coupled ocean, atmosphere and permafrost models will allow us to capture the complexity of the different parts of the system and evaluate the relative importance of different processes. Here we present results of a novel approach by means of dedicated permafrost model simulations. By applying an ensemble approach, we will show how uncertainties in boundary conditions and applied forcing scenarios control the future fate of the sub sea permafrost. We explore the impacts of the atmospheric forcings and its variabilities, various plausible flooding histories, different oceanographic boundary conditions, geothermal regimes, for instance, on the results. Extended simulations into the future for the next millennia, offer a glimpse of a selection of future scenarios. Our simulations have been driven by conditions of the Laptev Sea region in

  12. Conducting polymer actuators: From basic concepts to proprioceptive systems (United States)

    Martinez Gil, Jose Gabriel

    Designers and engineers have been dreaming for decades of motors sensing, by themselves, working and surrounding conditions, as biological muscles do originating proprioception. Here bilayer full polymeric artificial muscles were checked up to very high cathodic potential limits (-2.5 V) in aqueous solution by cyclic voltammetry. The electrochemical driven exchange of ions from the conducting polymer film, and the concomitant Faradaic bending movement of the muscle, takes place in the full studied potential range. The presence of trapped counterion after deep reduction was corroborated by EDX determinations giving quite high electronic conductivity to the device. The large bending movement was used as a tool to quantify the amount of water exchanged per reaction unit (exchanged electron or ion). The potential evolutions of self-supported films of conducting polymers or conducting polymers (polypyrrole, polyaniline) coating different microfibers, during its oxidation/reduction senses working mechanical, thermal, chemical or electrical variables. The evolution of the muscle potential from electrochemical artificial muscles based on electroactive materials such as intrinsically conducting polymers and driven by constant currents senses, while working, any variation of the mechanical (trailed mass, obstacles, pressure, strain or stress), thermal or chemical conditions of work. One physically uniform artificial muscle includes one electrochemical motor and several sensors working simultaneously under the same driving reaction. Actuating (current and charge) and sensing (potential and energy) magnitudes are present, simultaneously, in the only two connecting wires and can be read by the computer at any time. From basic polymeric, mechanical and electrochemical principles a physicochemical equation describing artificial proprioception has been developed. It includes and describes, simultaneously, the evolution of the muscle potential during actuation as a function of the

  13. A series elastic- and Bowden-cable-based actuation system for use as torque actuator in exoskeleton-type robots

    NARCIS (Netherlands)

    Veneman, J.F.; Ekkelenkamp, R.; Kruidhof, R.; van der Helm, F.C.T.; van der Kooij, Herman


    Within the context of impedance controlled exoskeletons, common actuators have important drawbacks. Either the actuators are heavy, have a complex structure or are poor torque sources, due to gearing or heavy nonlinearity. Considering our application, an impedance controlled gait rehabilitation

  14. Design and Development of Autonomous High Voltage Driving System for DEAP Actuator in Radiator Thermostat

    DEFF Research Database (Denmark)

    Huang, Lina; Zhang, Zhe; Andersen, Michael A. E.


    make a high voltage capacitive load driving system to be necessary. The only energy source battery determines it needs to be an autonomous system. The detailed system specifications have been introduced and the corresponding system level design has been proposed. In addition, the detailed design......In radiator thermostat applications, DEAP (Dielectric Electro Active Polymer) actuator tends to be a good candidate to replace the conventional self-actuating or step motor based actuator due to its intrinsic advantages. The capacitive property and high voltage (HV) driving demand of DEAP actuator...... and implementation information has been provided as well, including the power and control stage inside the high voltage converter, the output voltage measurement circuit, the feedback control, etc. Finally, the experimental results have been provided to validate the capability and performance of the driving system....

  15. Verification of operation of the actuator control system using the integration the B&R Automation Studio software with a virtual model of the actuator system (United States)

    Herbuś, K.; Ociepka, P.


    In the work is analysed a sequential control system of a machine for separating and grouping work pieces for processing. Whereas, the area of the considered problem is related with verification of operation of an actuator system of an electro-pneumatic control system equipped with a PLC controller. Wherein to verification is subjected the way of operation of actuators in view of logic relationships assumed in the control system. The actuators of the considered control system were three drives of linear motion (pneumatic cylinders). And the logical structure of the system of operation of the control system is based on the signals flow graph. The tested logical structure of operation of the electro-pneumatic control system was implemented in the Automation Studio software of B&R company. This software is used to create programs for the PLC controllers. Next, in the FluidSIM software was created the model of the actuator system of the control system of a machine. To verify the created program for the PLC controller, simulating the operation of the created model, it was utilized the approach of integration these two programs using the tool for data exchange in the form of the OPC server.

  16. Airborne Electro-Mechanical Actuator Test Stand for Development of Prognostic Health Management Systems (United States)

    National Aeronautics and Space Administration — With the advent of the next generation of aerospace systems equipped with fly-by-wire controls, electro- mechanical actuators (EMA) are quickly becoming components...


    National Research Council Canada - National Science Library

    M S Che Kob; B Supriyo; K B Tawi; I I Mazali


    ...) controller algorithm to engage the dry friction clutch. The EMFC is electro-mechanically actuated using a DC motor system, such that a smooth engagement process can be performed satisfactorily...

  18. Hybrid microcircuit metallization system for the SLL micro actuator

    Energy Technology Data Exchange (ETDEWEB)

    Hampy, R. E.; Knauss, G. L.; Komarek, E. E.; Kramer, D. K.; Villaueva, J.


    A thin film technique developed for the SLL Micro Actuator in which both gold and aluminum can be incorporated on sapphire or fine grained alumina substrates in a two-level metallization system is described. Tungsten is used as a lateral transition metal permitting electrical contact between the gold and aluminum without the two metals coming in physical contact. Silicon dioxide serves as an insulator between the tungsten and aluminum for crossover purposes, and vias through the silicon dioxide permit interconnections where desired. Tungsten-gold is the first level conductor except at crossovers where tungsten only is used and aluminum is the second level conductor. Sheet resistances of the two levels can be as low as 0.01 ohm/square. Line widths and spaces as small as 0.025 mm can be attained. A second layer of silicon dioxide is deposited over the metallization and opened for all gold and aluminum bonding areas. The metallization system permits effective interconnection of a mixture of devices having both gold and aluminum terminations without creating undesirable gold-aluminum interfaces. Processing temperatures up to 400/sup 0/C can be tolerated for short times without effect on bondability, conductor, and insulator characteristics, thus permitting silicon-gold eutectic die attachment, component soldering, and higher temperatures during gold lead bonding. Tests conducted on special test pattern circuits indicate good stability over the temperature range -55 to +150/sup 0/C. Aging studies indicate no degradation in characteristics in tests of 500 h duration at 150/sup 0/C.

  19. Knowledge-based Adaptive Tracking Control of Electro-hydraulic Actuator Systems

    DEFF Research Database (Denmark)

    Hansen, Poul Erik


    The paper deal with intelligent motion control and electro-hydraulic actuator systems for multiaxis machynes and robots.The research results are from the IMCIA research Programme supported by the Danish Technical Research Council, STVF.......The paper deal with intelligent motion control and electro-hydraulic actuator systems for multiaxis machynes and robots.The research results are from the IMCIA research Programme supported by the Danish Technical Research Council, STVF....

  20. Modeling and Simulation of Control Actuation System with Fuzzy-PID Logic Controlled Brushless Motor Drives for Missiles Glider Applications. (United States)

    Muniraj, Murali; Arulmozhiyal, Ramaswamy


    A control actuation system has been used extensively in automotive, aerospace, and defense applications. The major challenges in modeling control actuation system are rise time, maximum peak to peak overshoot, and response to nonlinear system with percentage error. This paper addresses the challenges in modeling and real time implementation of control actuation system for missiles glider applications. As an alternative fuzzy-PID controller is proposed in BLDC motor drive followed by linkage mechanism to actuate fins in missiles and gliders. The proposed system will realize better rise time and less overshoot while operating in extreme nonlinear dynamic system conditions. A mathematical model of BLDC motor is derived in state space form. The complete control actuation system is modeled in MATLAB/Simulink environment and verified by performing simulation studies. A real time prototype of the control actuation is developed with dSPACE-1104 hardware controller and a detailed analysis is carried out to confirm the viability of the proposed system.

  1. Strategic avionics technology definition studies. Subtask 3-1A: Electrical Actuation (ELA) systems (United States)

    Pond, Charles L.; Mcdermott, William A.; Lum, Ben T. F.


    Electrical actuator (ELA) power efficiency and requirements are examined for space system application. Requirements for Space Shuttle effector systems are presented, along with preliminary ELA trades and selection to form a preliminary ELA system baseline. Power and energy requirements for this baseline ELA system are applicable to the Space Shuttle and similar space vehicles.

  2. Application of metal hydride paper to simple pressure generator for use in soft actuator systems. (United States)

    Ino, Shuichi; Sakaki, Kouji; Hosono, Minako; Doi, Kouki; Shimada, Shigenobu; Chikai, Manabu


    Metal hydride (MH) actuators have a simple structure and a number of features that make them attractive for use in rehabilitation engineering and assistive technology. The MH actuator provides a high power-to-weight ratio, high-strain actuation, human-compatible softness, and noiseless operation, while being environmentally benign. On the other hand, there remain technical challenges to be overcome to improve the MH actuator regarding its speed of operation and energy efficiency, given the low heat conductivity of the MH powder that is used as the pressure generator for soft actuation. To overcome the issues of low heat conductivity and the handling of MH powder, we developed an MH paper, which is a special paper incorporating MH powder and carbon fiber, for use as a new pressure-generating element for a soft MH actuator system. In addition, the basic properties and structure of the proposed MH paper were investigated through scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and several thermodynamic experiments. The results of these experiments showed that the hydrogen absorption and desorption rates of the MH paper were significantly higher than those of the MH powder around room temperature.

  3. Tungsten trioxide (WO3) as an actuator electrode material for ISFET-based coulometric sensor-actuator systems

    NARCIS (Netherlands)

    van Kerkhof, J.C.; van Kerkhof, J.C.; Olthuis, Wouter; Bergveld, Piet; Bos, M.


    Acid or base concentrations can be determined by performing an acid-base titration with OH− or H+ ions, coulometrically generated by the electrolysis of water at a noble metal actuator electrode. This can be done very rapidly if the actuator electrode is in close proximity to an ISFET which is used

  4. Strategic avionics technology definition studies. Subtask 3-1A3: Electrical Actuation (ELA) Systems Test Facility (United States)

    Rogers, J. P.; Cureton, K. L.; Olsen, J. R.


    Future aerospace vehicles will require use of the Electrical Actuator systems for flight control elements. This report presents a proposed ELA Test Facility for dynamic evaluation of high power linear Electrical Actuators with primary emphasis on Thrust Vector Control actuators. Details of the mechanical design, power and control systems, and data acquisition capability of the test facility are presented. A test procedure for evaluating the performance of the ELA Test Facility is also included.

  5. Bioinspired Soft Actuation System Using Shape Memory Alloys

    Directory of Open Access Journals (Sweden)

    Matteo Cianchetti


    Full Text Available Soft robotics requires technologies that are capable of generating forces even though the bodies are composed of very light, flexible and soft elements. A soft actuation mechanism was developed in this work, taking inspiration from the arm of the Octopus vulgaris, specifically from the muscular hydrostat which represents its constitutive muscular structure. On the basis of the authors’ previous works on shape memory alloy (SMA springs used as soft actuators, a specific arrangement of such SMA springs is presented, which is combined with a flexible braided sleeve featuring a conical shape and a motor-driven cable. This robot arm is able to perform tasks in water such as grasping, multi-bending gestures, shortening and elongation along its longitudinal axis. The whole structure of the arm is described in detail and experimental results on workspace, bending and grasping capabilities and generated forces are presented. Moreover, this paper demonstrates that it is possible to realize a self-contained octopus-like robotic arm with no rigid parts, highly adaptable and suitable to be mounted on underwater vehicles. Its softness allows interaction with all types of objects with very low risks of damage and limited safety issues, while at the same time producing relatively high forces when necessary.

  6. Distributed electromechanical actuation system design for a morphing trailing edge wing (United States)

    Dimino, I.; Diodati, G.; Concilio, A.; Volovick, A.; Zivan, L.


    Next-generation flight control actuation technology will be based on "more electric" concepts to ensure benefits in terms of efficiency, weight and maintenance. This paper is concerned with the design of an un-shafted distributed servo-electromechanical actuation system, suited for morphing trailing edge wings of large commercial aircraft. It aims at producing small wing camber variations in the range between -5° and +5° in cruise, to enable aerodynamic efficiency improvements. The deployment kinematics is based on multiple "direct-drive" actuation, each made of light-weight compact lever mechanisms, rigidly connected to compliant ribs and sustained by load-bearing motors. Navier-Stokes computations are performed to estimate the pressure distribution over the interested wing region and the resulting hinge moments. These transfer to the primary structure via the driving mechanism. An electro-mechanical Matlab/Simulink model of the distributed actuation architecture is developed and used as a design tool, to preliminary evaluate the complete system performance. Implementing a multi-shaft strategy, each actuator is sized for the torque acting on the respective adaptive rib, following the effect of both the aerodynamic pressure and the morphing skin stiffness. Elastic trailing edge rotations and power needs are evaluated in operative conditions. Focus is finally given to the key challenges of the proposed concept: targeting quantifiable performance improvements while being compliant to the demanding requirements in terms of reliability and safety.

  7. A dual loop strategy for the design of a control surface actuation system with nonlinear limitations (United States)

    De Gaspari, Alessandro; Mannarino, Andrea; Mantegazza, Paolo


    A novel frequency-based optimization algorithm, suitable to tune generic controllers involved in the dual loop architectures, is presented. A control scheme, based on standard industrial regulators, is adopted to incorporate nonlinear constraints reproducing technological limitations, in a control surfaces actuation system installed on a wind tunnel aeroelastic demonstrator. An integrated observer for disturbance rejection helps to meet one of the required constraints when aerodynamic loads are present. Numerical and experimental results are presented with the aim to design the actuation system and validate the methodology, considering both standard input signals and realistic command profiles.

  8. Sensor and Actuator Fault-Hiding Reconfigurable Control Design for a Four-Tank System Benchmark

    DEFF Research Database (Denmark)

    Hameed, Ibrahim; El-Madbouly, Esam I; Abdo, Mohamed I


    Fault detection and compensation plays a key role to fulfill high demands for performance and security in today's technological systems. In this paper, a fault-hiding (i.e., tolerant) control scheme that detects and compensates for actuator and sensor faults in a four-tank system benchmark...

  9. Optimal Sensors and Actuators Placement for Large-Scale Unstable Systems via Restricted Genetic Algorithm

    DEFF Research Database (Denmark)

    Seyyed Sakha, Masoud; Shaker, Hamid Reza


    expensive. The computational burden is significant in particular for large-scale systems. In this paper, we develop a new technique for placing sensor and actuator in large-scale systems by using Restricted Genetic Algorithm (RGA). The RGA is a kind of genetic algorithm which is developed specifically...

  10. Torque And Speed in the Actuating of Mechatronic Systems, a Case Study

    Directory of Open Access Journals (Sweden)

    Constantin Paul Roman


    Full Text Available The paper presents a mechatronic system programmed and controlled by a PLC and inverter for driving an AC motor. Torque and speed for part of mechatronic systems depends of actuating source for cinematic structure. In our research, mechanical structure consists of an AC motor. A technique for setting and control of speed and torque is presented.

  11. Design Comparison of Autonomous High Voltage Driving System for DEAP Actuator

    DEFF Research Database (Denmark)

    Huang, Lina; Pittini, Riccardo; Zhang, Zhe


    As a new type of smart material, the Dielectric Electro Active Polymer (DEAP) is introduced in terms of configuration, working principle and potential applications. The design of an autonomous high voltage driving system for DEAP actuator is investigated. The system configuration and the design...

  12. Optimization problems for a class of switched Pritchard-Salamon systems with applications to moving actuators

    NARCIS (Netherlands)

    Iftime, Orest V.; Demetriou, Michael A.; Parisini, T.


    This paper provides applicable methodologies for optimization problems of a spatially moving (or scanning) actuator within the theoretical framework of switched Pritchard-Salamon systems. This is a class of distributed parameter systems that allows for unbounded input and output operators. Two


    Energy Technology Data Exchange (ETDEWEB)

    John V. Fernandez; David S. Pixton


    A history and project summary of the development of an integrated drilling system using a mud-actuated down-hole hammer as its primary engine are given. The summary includes laboratory test results, including atmospheric tests of component parts and simulated borehole tests of the hammer system. Several remaining technical hurdles are enumerated. A brief explanation of commercialization potential is included. The primary conclusion for this work is that a mud actuated hammer can yield substantial improvements to drilling rate in overbalanced, hard rock formations. A secondary conclusion is that the down-hole mud actuated hammer can serve to provide other useful down-hole functions including generation of high pressure mud jets, generation of seismic and sonic signals, and generation of diagnostic information based on hammer velocity profiles.

  14. Hydraulic vs. Electric: A Review of Actuation Systems in Offshore Drilling Equipment

    Directory of Open Access Journals (Sweden)

    Witold Pawlus


    Full Text Available This article presents a survey on actuation systems encountered in offshore drilling applications. Specifically, it focuses on giving a comparison of hydraulic and electric drivetrains along with detailed explanations of their advantages and drawbacks. A significant number of industrial case studies is examined in addition to the collection of academic publications, in order to accurately describe the current market situation. Some key directions of research and development required to satisfy increasing demands on powertrains operating offshore are identified. The impact of the literature and application surveys is further strengthened by benchmarking two designs of a full-scale pipe handling machine. Apart from other benefits, the electrically actuated machine reduces the total power consumption by 70% compared to its hydraulically driven counterpart. It is concluded that electric actuation systems, among other advantages, in general offer higher efficiency and flexibility, however, in some specific applications (such as energy accumulation or translational motion control hydraulic powertrains are favorable.

  15. Pneumatic Actuation of a 2-Link Robotic System | Ramjug-Ballgobin ...

    African Journals Online (AJOL)

    The investigation of a 2-link pneumatic robotic system, using robotic and electric actuators, will be made. For the sake of representation, the prototype will be made of available materials in the market to fulfil its requirements. An insight into robots explaining the various functions in the human world will be outlined. The aim of ...

  16. Pulse mode actuation-readout system based on MEMS resonator for liquid sensing

    DEFF Research Database (Denmark)

    Tang, Meng; Cagliani, Alberto; Davis, Zachary James


    A MEMS (Micro-Electro-Mechanical Systems) bulk disk resonator is applied for mass sensing under its dynamic mode. The classical readout circuitry involves sophisticated feedback loop and feedthrough compensation. We propose a simple straightforward non-loop pulse mode actuation and capacitive...

  17. Design of integrated systems for control and detection of actuator/sensor faults

    DEFF Research Database (Denmark)

    Stoustrup, J.; Grimble, M.J.; Niemann, Hans Henrik


    Consider control systems operating under potentially faulty conditions. Discusses the problems of designing a single unit which not only handle the required control but also identified faults occuring in actuators and sensors. In common practice, unites for control and for diagnosis are designed...

  18. Efficient control of servo pneumatic actuator system utilizing by-pass ...

    Indian Academy of Sciences (India)

    Efficient control of servo pneumatic actuator system utilizing by-pass valve and digital sliding mode. VLADISLAV BLAGOJEVI ´C1,∗, DRAGAN ŠEŠLIJA2,. MIODRAG STOJILJKOVI ´C1 and SLOBODAN DUDI ´C2. 1Faculty of Mechanical Engineering, University of Nis, Aleksandra Medvedeva 14,. 18000 Nis, Serbia. 2Faculty ...

  19. AMSD Cryo Actuator Testing (United States)

    Mullette, Mark; Matthews, Gary; Russell, Kevin (Technical Monitor)


    The actuator technology required for AMSD and subsequently NGST are critical in the successful development for future cryogenic systems. Kodak has undertaken an extensive test plan to determine the performance of the force actuators developed under the AMSD program. These actuators are currently in testing at MSFC and are expected to finish this test cycle in early June 2002.

  20. Innovative sub sea pipeline maintenance in line with emerging offshore trends and maintenance safety standards

    Energy Technology Data Exchange (ETDEWEB)

    Lim, George [T.D. Williamson, Inc., Tulsa, OK (United States)


    Sub sea hot tapping of pipelines is performed for a variety of reasons, including tie-ins, pipeline repair, insertion of instrumentation, facilitating chemical injection or providing access for temporary isolation tools. The full hot tap process - that is, installing the hot tap assembly, performing the tap and recovering the hot tap machine - is normally conducted with diver assistance. After bolting the assembly of the machine, isolation valve and fitting to the pipeline (or machine and isolation valve to a pre-installed flanged membrane on the pipeline), the divers then operate the machine to perform the tap, under instructions from - and supervision by - hot tap technicians located on deck of the diving support vessel (DSV). Subsequent unbolting and removal of the hot tap machine is also carried out by the divers. The demands of deep water have necessitated development of a totally diver-less, remote-controlled system. Diver operations are limited to a maximum of 300 meters of water depth, whereas a significant portion of existing sub sea field infrastructure, as well as projected future developments, are in deeper waters in depths up to 3,000 meters. In addition, diver safety concerns in shallow water, as well as impaired diver efficiency in difficult environmental conditions such as wave breaking zones, prompts the call for a reduction of diver exposure or complete elimination of diver assistance. The recent completion of a remote-controlled hot tap machine (the Sub sea 1200RC Tapping Machine) is a first step toward developing a totally diver-less system. The installation of the hot tap assembly and subsequent removal of the machine still require diver assistance, but the performance of the tap itself is remotely controlled by a hot tap technician from the deck of the DSV. The concept is a topside-driven hot tap machine with 'passive Remote Operating Vehicle (ROV) interface', which means a stationary ROV with its hydraulics and control system

  1. Time response for sensor sensed to actuator response for mobile robotic system (United States)

    Amir, N. S.; Shafie, A. A.


    Time and performance of a mobile robot are very important in completing the tasks given to achieve its ultimate goal. Tasks may need to be done within a time constraint to ensure smooth operation of a mobile robot and can result in better performance. The main purpose of this research was to improve the performance of a mobile robot so that it can complete the tasks given within time constraint. The problem that is needed to be solved is to minimize the time interval between sensor detection and actuator response. The research objective is to analyse the real time operating system performance of sensors and actuators on one microcontroller and on two microcontroller for a mobile robot. The task for a mobile robot for this research is line following with an obstacle avoidance. Three runs will be carried out for the task and the time between the sensors senses to the actuator responses were recorded. Overall, the results show that two microcontroller system have better response time compared to the one microcontroller system. For this research, the average difference of response time is very important to improve the internal performance between the occurrence of a task, sensors detection, decision making and actuator response of a mobile robot. This research helped to develop a mobile robot with a better performance and can complete task within the time constraint.

  2. Adaptive tracking control for active suspension systems with non-ideal actuators (United States)

    Pan, Huihui; Sun, Weichao; Jing, Xingjian; Gao, Huijun; Yao, Jianyong


    As a critical component of transportation vehicles, active suspension systems are instrumental in the improvement of ride comfort and maneuverability. However, practical active suspensions commonly suffer from parameter uncertainties (e.g., the variations of payload mass and suspension component parameters), external disturbances and especially the unknown non-ideal actuators (i.e., dead-zone and hysteresis nonlinearities), which always significantly deteriorate the control performance in practice. To overcome these issues, this paper synthesizes an adaptive tracking control strategy for vehicle suspension systems to achieve suspension performance improvements. The proposed control algorithm is formulated by developing a unified framework of non-ideal actuators rather than a separate way, which is a simple yet effective approach to remove the unexpected nonlinear effects. From the perspective of practical implementation, the advantages of the presented controller for active suspensions include that the assumptions on the measurable actuator outputs, the prior knowledge of nonlinear actuator parameters and the uncertain parameters within a known compact set are not required. Furthermore, the stability of the closed-loop suspension system is theoretically guaranteed by rigorous mathematical analysis. Finally, the effectiveness of the presented adaptive control scheme is confirmed using comparative numerical simulation validations.

  3. Hydroacoustic control actuator for diver or ROV (Remote Operated Valves); Atuador de controle hidroacustico para valvulas operadas por mergulhador ou ROV

    Energy Technology Data Exchange (ETDEWEB)

    Kuchpil, Cassio [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Tecnologia Submarina]. E-mail:; Lima, Luiz Eduardo Alves de [Transcontrol Comercio e Industria de Produtos Eletronicos Ltda., Rio de Janeiro, RJ (Brazil)]. E-mail:


    This paper intends to describe the development did by TRANSCONTROL and CENPES- PETROBRAS during the agreement number 540.4.063.00-0 to develop the Hydro acoustic Control Actuator of Diver or ROV Operated Valves, industrialization of the prototype, creation of engineering documents and execution of qualification and field tests. This System is useful to control devices remotely using Hydro acoustic Modems that operates electrical actuators using battery packs installed near the sub sea valves. The control is done by similar hydro acoustic units mounted on boats or platforms. In addition, it can obtain remotely the status and position of the actuator, its power consumption and battery status, information that turns the operation more secure, allowing better operation planning and maintenance. (author)

  4. A nonlinear scalable model for designing ionic polymer-metal composite actuator systems (United States)

    McDaid, A. J.; Aw, K. C.; Hämmerle, E.; Xie, S. Q.


    This paper proposes a conclusive scalable model for Ionic Polymer Metal Composites (IPMC) actuators and their interactions with mechanical systems and external loads. This dynamic, nonlinear model accurately predicts the displacement and force actuation in air for a large range of input voltages. The model addresses all the requirements of a useful design tool for IPMC actuators and is intended for robotic and bio-mimetic (artificial muscle) applications which operate at low frequencies. The response of the IPMC is modeled in three stages, (i) a nonlinear equivalent electrical circuit to predict the current drawn, (ii) an electro-mechanical coupling term, representing the conversion of ion flux to a stress generated in the polymer membrane and (iii) a mechanical beam model which includes an electrically induced torque for the polymer. Mechanical outputs are in the rotational coordinate system, 'tip angle' and 'torque output', to give more practical results for the design and simulation of mechanisms. Model parameters are obtained using the dynamic time response and results are presented demonstrating excellent correspondence between the model and experimental results. This newly developed model is a large step forward, aiding in the progression of IPMCs towards wide acceptance as replacements to traditional actuators.

  5. Design of a Compact Actuation and Control System for Flexible Medical Robots. (United States)

    Morimoto, Tania K; Hawkes, Elliot Wright; Okamura, Allison M


    Flexible medical robots can improve surgical procedures by decreasing invasiveness and increasing accessibility within the body. Using preoperative images, these robots can be designed to optimize a procedure for a particular patient. To minimize invasiveness and maximize biocompatibility, the actuation units of flexible medical robots should be placed fully outside the patient's body. In this letter, we present a novel, compact, lightweight, modular actuation, and control system for driving a class of these flexible robots, known as concentric tube robots. A key feature of the design is the use of three-dimensional printed waffle gears to enable compact control of two degrees of freedom within each module. We measure the precision and accuracy of a single actuation module and demonstrate the ability of an integrated set of three actuation modules to control six degrees of freedom. The integrated system drives a three-tube concentric tube robot to reach a final tip position that is on average less than 2 mm from a given target. In addition, we show a handheld manifestation of the device and present its potential applications.

  6. Magnetorheological valve based actuator for improvement of passively controlled turbocharger system (United States)

    Bahiuddin, I.; Mazlan, S. A.; Imaduddin, F.; Ubaidillah, Ichwan, B.


    Variable geometry turbochargers have been widely researched to fulfil the current engine stringent regulations. The passively controlled turbocharger (PCT) concept has been proposed to reduce energy consumption by utilizing the emission energy to move the actuator. However, it only covered a small range operating condition. Therefore, a magnetorheological(MR) Valve device, as typical smart material devices to enhance a passive device, is proposed to improve the PCT. Even though the benefits have been considered for the compactness and easiness to connect to an electrical system, the number of publications regarding the MR application within engine system is hard to be found. Therefore, this paper introduces a design of an MR Valve in a turbocharger. The main challenge is to make sure its capability to produce a sufficient total pressure drop. To overcome the challenge, its material properties, shape and pressure drop calculation has been analyzed to fulfil the requirement. Finally, to get a more understanding of actuator performance, the actuator response was simulated by treating the exhaust gas pressure as an input. It shows that the new MR actuator has a potential dynamic to improve the PCT controllability.

  7. Bio-Inspired Control of an Arm Exoskeleton Joint with Active-Compliant Actuation System

    Directory of Open Access Journals (Sweden)

    Michele Folgheraiter


    Full Text Available This paper presents the methodology followed on the design of a multi-contact point haptic interface that uses a bio-inspired control approach and a novel actuation system. The combination of these components aims at creating a system that increases the operability of the target, and, at the same time, enables an intuitive and safe tele-operation of any complex robotic system of any given morphology. The novelty lies on the combination of a thoughtful kinematic structure driven by an active-compliant actuation system and a bio-inspired paradigm for its regulation. Due to the proposed actuation approach, the final system will achieve the condition of wearable system. On that final solution, each joint will be able to change its stiffness depending on the task to be executed, and on the anatomical features of each individual. Moreover, the system provides a variety of safety mechanisms at different levels to prevent causing any harm to the operator. In future, the system should allow the complete virtual immersion of the user within the working scenario.

  8. Simplified design of the coulometric sensor-actuator system by the application of a time-dependent actuator current

    NARCIS (Netherlands)

    Olthuis, Wouter; Bergveld, Piet


    Acid or base concentrations can be determined by performing an acid-base titration with coulometrically generated OH¿ or H+ ions at a noble metal actuator electrode in close proximity to the pH-sensitive gate of an ISFET. It is shown, both theoretically and experimentally, that the relation between

  9. Influence of ordered morphology on the anisotropic actuation in uniaxially oriented electroactive polymer systems. (United States)

    Park, Jong Keun; Moore, Robert B


    Ionic polymer-metal composites (IPMCs) are electroactive materials that undergo bending motions with the stimulus of a relatively weak electric field. To understand the fundamental role of the nanoscale morphology of the ionomer membrane matrix in affecting the actuation behavior of IPMC systems, we evaluated the actuation performance of IPMC materials subjected to uniaxial orientation. The perfluorinated ionomer nanostructure altered by uniaxial orientation mimicks the fibrillar structure of biological muscle tissue and yields a new anisotropic actuation response. It is evident that IPMCs cut from films oriented perpendicular to the draw direction yield tip-displacement values that are significantly greater than those of unoriented IPMCs. In contrast, IPMCs cut from films oriented parallel to the draw direction appear to resist bending and yield tip-displacement values that are much less than those of unoriented IPMCs. This anisotropic actuation behavior is attributed, in part, to the contribution of the fibrillar morphology to the bulk bending modulus. As an additional contribution, electrically stimulated water swelling perpendicular to the rodlike aggregate axis facilitates bending in the perpendicular direction.

  10. Influence of Ordered Morphology on the Anisotropic Actuation in Uniaxially Oriented Electroactive Polymer Systems

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Keun; Moore, Robert B.; (VPI-SU)


    Ionic polymer-metal composites (IPMCs) are electroactive materials that undergo bending motions with the stimulus of a relatively weak electric field. To understand the fundamental role of the nanoscale morphology of the ionomer membrane matrix in affecting the actuation behavior of IPMC systems, we evaluated the actuation performance of IPMC materials subjected to uniaxial orientation. The perfluorinated ionomer nanostructure altered by uniaxial orientation mimicks the fibrillar structure of biological muscle tissue and yields a new anisotropic actuation response. It is evident that IPMCs cut from films oriented perpendicular to the draw direction yield tip-displacement values that are significantly greater than those of unoriented IPMCs. In contrast, IPMCs cut from films oriented parallel to the draw direction appear to resist bending and yield tip-displacement values that are much less than those of unoriented IPMCs. This anisotropic actuation behavior is attributed, in part, to the contribution of the fibrillar morphology to the bulk bending modulus. As an additional contribution, electrically stimulated water swelling perpendicular to the rodlike aggregate axis facilitates bending in the perpendicular direction.


    CERN Document Server

    Bertarelli, A; Perret, R; Smas, P; CERN. Geneva. EN Department


    In order to cope with the highly destructive particle beam of the LHC, the cleaning and collimation system must fulfill very severe requirements. The actuation system of the LHC Collimators is a key element to meet the specifications, particularly in terms of precision and reliability. Each collimator jaw has to be moved with a very high accuracy to place the active surface at the required position with respect to the proton beam; at the same time the system must be adjustable and flexible to adapt to the uncertainties and variations in the beam tuning. In this note the general design of the actuation system for the various collimator designs is presented and particular emphasis is given to the analysis of the torque which the stepper motors must provide to move the jaws in and back and to the dynamical behaviour of the system in the event of malfunctioning when auto-retraction of the jaws is required. In the appendix, details are given on the estimated performances of the actuation system for different colli...

  12. Design of Servo Scheme and Drive Electronics for the Integrated Electrohydraulic Actuation System of RLV-TD (United States)

    Kurian, Priya C.; Gopinath, Anish; Shinoy, K. S.; Santhi, P.; Sundaramoorthy, K.; Sebastian, Baby; Jaya, B.; Namboodiripad, M. N.; Mookiah, T.


    Reusable Launch Vehicle-Technology Demonstrator (RLV-TD) is a system which has the ability to carry a payload from the earth's surface to the outer space more than once. The control actuation forms the major component of the control system and it actuates the control surfaces of the RLV-TD based on the control commands. Eight electro hydraulic actuators were used in RLV-TD for vectoring the control surfaces about their axes. A centralised Hydraulic Power Generating Unit (HPU) was used for powering the eight actuators located in two stages. The actuation system had to work for the longest ever duration of about 850 s for an Indian launch vehicle. High bandwidth requirement from autopilot was met by the servo design using the nonlinear mathematical model. Single Control Electronics which drive four electrohydraulic actuators was developed for each stage. High power electronics with soft start scheme was realized for driving the BLDC motor which is the prime mover for hydraulic pump. Many challenges arose due to single HPU for two stages, uncertainty of aero load, higher bandwidth requirements etc. and provisions were incorporated in the design to successfully overcome them. This paper describes the servo design and control electronics architecture of control actuation system.

  13. Design of Servo Scheme and Drive Electronics for the Integrated Electrohydraulic Actuation System of RLV-TD (United States)

    Kurian, Priya C.; Gopinath, Anish; Shinoy, K. S.; Santhi, P.; Sundaramoorthy, K.; Sebastian, Baby; Jaya, B.; Namboodiripad, M. N.; Mookiah, T.


    Reusable Launch Vehicle-Technology Demonstrator (RLV-TD) is a system which has the ability to carry a payload from the earth's surface to the outer space more than once. The control actuation forms the major component of the control system and it actuates the control surfaces of the RLV-TD based on the control commands. Eight electro hydraulic actuators were used in RLV-TD for vectoring the control surfaces about their axes. A centralised Hydraulic Power Generating Unit (HPU) was used for powering the eight actuators located in two stages. The actuation system had to work for the longest ever duration of about 850 s for an Indian launch vehicle. High bandwidth requirement from autopilot was met by the servo design using the nonlinear mathematical model. Single Control Electronics which drive four electrohydraulic actuators was developed for each stage. High power electronics with soft start scheme was realized for driving the BLDC motor which is the prime mover for hydraulic pump. Many challenges arose due to single HPU for two stages, uncertainty of aero load, higher bandwidth requirements etc. and provisions were incorporated in the design to successfully overcome them. This paper describes the servo design and control electronics architecture of control actuation system.

  14. A Systematic Methodology for Actuator Augmentation in the Supervisory Control of Discrete Event Systems

    Directory of Open Access Journals (Sweden)

    Vigyan Chandra


    Full Text Available Supervisory control theory of discrete event systems in the Ramade-Wonham paradigm addresses the problem of restricting the system evolution so that it conforms to certain predefined behavior commonly referred to as specifications. This theory states that a sequence of events that cause the plant to violate the specifications is suitably pruned or eliminated. However, in doing so, event traces, partial prefixes of which that actually meet control specification are eliminated as well. This happens for instance whenever a chain of uncontrollable event extensions render the plant behavior trajectory irrevocably outside the outlined specifications. Such partial conformance can be ensured if the capability of the system is augmented by additional actuators so that in the augmented plant there is a greater degree of control over uncontrollable events. It does not follow trivially where such actuators are to be placed. We propose an algorithm that enables us to identify states of the automaton where the new actuators need to be inserted, thus enlarging the scope of its applicability to system identification purposes as well.


    Directory of Open Access Journals (Sweden)



    Full Text Available The paper presents the stages of developing new, light, eco-friendly and bionic gripper systems. Gripping is achieved by means of original, self-adaptive, bio-inspired systems, with a pneumatic muscle as motion generator. The method underlying the development of these new gripping systems is based on the creation of concepts by analogy, an instrument aimed at widening the inspiration horizon in designing by using models from nature.

  16. Flight qualification of mortar-actuated parachute deployment systems (United States)

    Pleasants, J. E.


    A brief discussion outlines background of mortar use in parachute deployment systems. A description of the system operation is presented. Effects of the environment on performance are discussed as well as the instrumentation needed to assess this performance. Power unit qualification and lot qualification for shear pins and cartridges is delineated. Functional mortar system tests are described. Finally, bridle deployment and parachute deployment are discussed.

  17. Design and Implementation of Output Feedback Control for Piezo Actuated Structure Using Embedded System

    Directory of Open Access Journals (Sweden)



    Full Text Available This paper presents the design of periodic output feedback control using state feedback gain to control the vibration of piezo actuated cantilever beam. The effectiveness of the controller is evaluated through simulation and experimentally by exciting the structure at resonance. Real time implementation of the controller is done using microcontroller. The closed loop eigen values of the system with periodic output feedback and state feedback are identical.

  18. Modelling study, analysis and robust servo control of pneumatic cylinder actuator systems


    Wang, J. (Jihong); Wang, D. J. D.; Moore, Philip R.; Pu, Junsheng


    Paper reports results of modelling, analysis and control implementations of pneumatic servo systems undertaken at our specialist laboratory in DMU, that builds on foundation studies in the DHSM programme “High Speed Servo Pneumatic Actuator Systems”, EPSRC/DTI Programme Grant GR/K/38663 (Collaborators: IMC/Enidine, Mars Confectionary and Baldor-Optimised Control). These techniques have been applied in areas such as packaging machinery in the confectionary industry (jayan.ragavan@btinternet.c...

  19. Fault-tolerant Control of Discrete-time LPV systems using Virtual Actuators and Sensors

    DEFF Research Database (Denmark)

    Tabatabaeipour, Mojtaba; Stoustrup, Jakob; Bak, Thomas


    the input-to-state stability (ISS) of the closed-loop reconfigured system. Moreover, we obtain performances in terms of the ISS gains for the virtual actuator, the virtual sensor and their interconnection. Minimizing these performances is formulated as convex optimization problems subject to LMI constraints....... Finally, the effectiveness of the method is demonstrated via a numerical example and stator current control of an induction motor....

  20. Feasibility of an anticipatory noncontact precrash restraint actuation system

    Energy Technology Data Exchange (ETDEWEB)

    Kercel, S.W.; Dress, W.B. [Oak Ridge National Lab., TN (United States). Instrumentation and Controls Div.


    The problem of providing an electronic warning of an impending crash to a precrash restraint system a fraction of a second before physical contact differs from more widely explored problems, such as providing several seconds of crash warning to a driver. One approach to precrash restraint sensing is to apply anticipatory system theory. This consists of nested simplified models of the system to be controlled and of the system`s environment. It requires sensory information to describe the ``current state`` of the system and the environment. The models use the sensory data to make a faster-than-real-time prediction about the near future. Anticipation theory is well founded but rarely used. A major problem is to extract real-time current-state information from inexpensive sensors. Providing current-state information to the nested models is the weakest element of the system. Therefore, sensors and real-time processing of sensor signals command the most attention in an assessment of system feasibility. This paper describes problem definition, potential ``showstoppers,`` and ways to overcome them. It includes experiments showing that inexpensive radar is a practical sensing element. It considers fast and inexpensive algorithms to extract information from sensor data.

  1. Hydraulic System Design of Hydraulic Actuators for Large Butterfly Valves

    Directory of Open Access Journals (Sweden)

    Ye HUANG


    Full Text Available Hydraulic control systems of butterfly valves are presently valve-controlled and pump-controlled. Valve-controlled hydraulic systems have serious power loss and generate much heat during throttling. Pump-controlled hydraulic systems have no overflow or throttling losses but are limited in the speed adjustment of the variable-displacement pump, generate much noise, pollute the environment, and have motor power that does not match load requirements, resulting in low efficiency under light loads and wearing of the variable-displacement pump. To overcome these shortcomings, this article designs a closed hydraulic control system in which an AC servo motor drives a quantitative pump that controls a spiral swinging hydraulic cylinder, and analyzes and calculates the structure and parameters of a spiral swinging hydraulic cylinder. The hydraulic system adjusts the servo motor’s speed according to the requirements of the control system, and the motor power matches the power provided to components, thus eliminating the throttling loss of hydraulic circuits. The system is compact, produces a large output force, provides stable transmission, has a quick response, and is suitable as a hydraulic control system of a large butterfly valve.

  2. On-board diagnostics of fully variable valve actuator systems in spark-ignited combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Sarac, Ipek


    Variable valve actuation (VVA) is being employed in contemporary engines to improve fuel consumption, torque characteristics and emissions of combustion engines by enabling the realization of different combustion strategies. Fully variable valve actuation (FVVA) makes it possible to apply a wider range of strategies (e.g., homogenous charge compression ignition (HCCI), dethrottling, internal residual gas mechanism, 2/4 Stroke Switching). With FVVA, the gas exchange valves can be actuated at arbitrary points in time, with separate variable lifting for the intake and exhaust valves of each cylinder. Making FVVA systems ready for the market requires to provide the system with appropriate fault-diagnostic functionality. Additional degrees of freedom of FVVA systems introduce different fault cases which have to be considered in terms of their emission relevance within the scope of diagnostics standards such as On-Board Diagnosis II (OBD II). The faults and their effects on emissions have not been analyzed by any other study, yet. To fill this gab, here the possible faults are generated using a four-cylinder gasoline camless test bench engine. Measurements are carried out using different strategies at low loads, namely dethrottling with early intake valve closing and combining high internal residual gas with dethrottling. Each fault case is thoroughly analyzed, and the emission-relevant faults are pointed out for initial consideration. A trivial approach to diagnose fully variable valve actuators is to introduce position sensors for each actuator to track the valve lift curve. However, this approach increases the cost of the system undesirably. Thus, here alternative methods are explored such as indirect use of common powertrain sensors. Considering that active diagnosis may lead to suboptimal engine control schemes, the possibilities of fault detection and isolation are investigated without relying on active diagnosis. Air path sensors are affected foremost by any

  3. Motion control of multi-actuator hydraulic systems for mobile machineries: Recent advancements and future trends (United States)

    Xu, Bing; Cheng, Min


    This paper presents a survey of recent advancements and upcoming trends in motion control technologies employed in designing multi-actuator hydraulic systems for mobile machineries. Hydraulic systems have been extensively used in mobile machineries due to their superior power density and robustness. However, motion control technologies of multi-actuator hydraulic systems have faced increasing challenges due to stringent emission regulations. In this study, an overview of the evolution of existing throttling control technologies is presented, including open-center and load sensing controls. Recent advancements in energy-saving hydraulic technologies, such as individual metering, displacement, and hybrid controls, are briefly summarized. The impact of energy-saving hydraulic technologies on dynamic performance and control solutions are also discussed. Then, the advanced operation methods of multi-actuator mobile machineries are reviewed, including coordinated and haptic controls. Finally, challenges and opportunities of advanced motion control technologies are presented by providing an overall consideration of energy efficiency, controllability, cost, reliability, and other aspects.

  4. A fuzzy robust control scheme for vibration suppression of a nonlinear electromagnetic-actuated flexible system (United States)

    Tavakolpour-Saleh, A. R.; Haddad, M. A.


    In this paper, a novel robust vibration control scheme, namely, one degree-of-freedom fuzzy active force control (1DOF-FAFC) is applied to a nonlinear electromagnetic-actuated flexible plate system. First, the flexible plate with clamped-free-clamped-free (CFCF) boundary conditions is modeled and simulated. Then, the validity of the simulation platform is evaluated through experiment. A nonlinear electromagnetic actuator is developed and experimentally modeled through a parametric system identification scheme. Next, the obtained nonlinear model of the actuator is applied to the simulation platform and performance of the proposed control technique in suppressing unwanted vibrations is investigated via simulation. A fuzzy controller is applied to the robust 1DOF control scheme to tune the controller gain using acceleration feedback. Consequently, an intelligent self-tuning vibration control strategy based on an inexpensive acceleration sensor is proposed in the paper. Furthermore, it is demonstrated that the proposed acceleration-based control technique owns the benefits of the conventional velocity feedback controllers. Finally, an experimental rig is developed to investigate the effectiveness of the 1DOF-FAFC scheme. It is found that the first, second, and third resonant modes of the flexible system are attenuated up to 74%, 81%, and 90% respectively through which the effectiveness of the proposed control scheme is affirmed.

  5. Robust Adaptive Sliding Mode Consensus of Multiagent Systems with Perturbed Communications and Actuators

    Directory of Open Access Journals (Sweden)

    Xiao-Zheng Jin


    Full Text Available This paper deals with the asymptotic consensus problem for a class of multiagent systems with time-varying additive actuator faults and perturbed communications. The L2 performance of systems is also considered in the consensus controller designs. The upper and lower bounds of faults and perturbations in actuators and communications and controller gains are assumed to be unknown but can be estimated by designing some indirect adaptive laws. Based on the information from the adaptive estimation mechanism, the distributed robust adaptive sliding mode controllers are constructed to automatically compensate for the effects of faults and perturbations and to achieve any given level of L2 gain attenuation from external disturbance to consensus errors. Through Lyapunov functions and adaptive schemes, the asymptotic consensus of resulting adaptive multiagent system can be achieved with a specified performance criterion in the presence of perturbed communications and actuators. The effectiveness of the proposed design is illustrated via a decoupled longitudinal model of F-18 aircraft.

  6. Modeling and Simulation of Control Actuation System with Fuzzy-PID Logic Controlled Brushless Motor Drives for Missiles Glider Applications (United States)

    Muniraj, Murali; Arulmozhiyal, Ramaswamy


    A control actuation system has been used extensively in automotive, aerospace, and defense applications. The major challenges in modeling control actuation system are rise time, maximum peak to peak overshoot, and response to nonlinear system with percentage error. This paper addresses the challenges in modeling and real time implementation of control actuation system for missiles glider applications. As an alternative fuzzy-PID controller is proposed in BLDC motor drive followed by linkage mechanism to actuate fins in missiles and gliders. The proposed system will realize better rise time and less overshoot while operating in extreme nonlinear dynamic system conditions. A mathematical model of BLDC motor is derived in state space form. The complete control actuation system is modeled in MATLAB/Simulink environment and verified by performing simulation studies. A real time prototype of the control actuation is developed with dSPACE-1104 hardware controller and a detailed analysis is carried out to confirm the viability of the proposed system. PMID:26613102

  7. Modeling and Simulation of Control Actuation System with Fuzzy-PID Logic Controlled Brushless Motor Drives for Missiles Glider Applications

    Directory of Open Access Journals (Sweden)

    Murali Muniraj


    Full Text Available A control actuation system has been used extensively in automotive, aerospace, and defense applications. The major challenges in modeling control actuation system are rise time, maximum peak to peak overshoot, and response to nonlinear system with percentage error. This paper addresses the challenges in modeling and real time implementation of control actuation system for missiles glider applications. As an alternative fuzzy-PID controller is proposed in BLDC motor drive followed by linkage mechanism to actuate fins in missiles and gliders. The proposed system will realize better rise time and less overshoot while operating in extreme nonlinear dynamic system conditions. A mathematical model of BLDC motor is derived in state space form. The complete control actuation system is modeled in MATLAB/Simulink environment and verified by performing simulation studies. A real time prototype of the control actuation is developed with dSPACE-1104 hardware controller and a detailed analysis is carried out to confirm the viability of the proposed system.

  8. Design and fabrication of a micro PZT cantilever array actuator for applications in fluidic systems

    DEFF Research Database (Denmark)

    Kim, H.; In, C.; Yoon, Gil Ho


    In this article, a micro cantilever array actuated by PZT films is designed and fabricated for micro fluidic systems. The design features for maximizing tip deflections and minimizing fluid leakage are described. The governing equation of the composite PZT cantilever is derived and the actuating...... behavior predicted. The calculated value of the tip deflection was 15 pm at 5 V. The fabrication process from SIMOX (Separation by oxygen ion implantation) wafer is presented in detail with the PZT film deposition process. The PZT films are characterized by investigating the ferroelectric properties......, dielectric constant, and dielectric loss. Tip deflections of 12 mu m at 5 V are measured, which agreed well with the predicted value. The 18 mu l/s leakage rate of air was observed at a pressure difference of 1000 Pa. Micro cooler is introduced, and its possible application to micro compressor is discussed....

  9. Electromechanical transducers at the nanoscale: actuation and sensing of motion in nanoelectromechanical systems (NEMS). (United States)

    Ekinci, K L


    Electromechanical devices are rapidly being miniaturized, following the trend in commercial transistor electronics. Miniature electromechanical devices--now with dimensions in the deep sub-micrometer range--are envisioned for a variety of applications as well as for accessing interesting regimes in fundamental physics. Among the most important technological challenges in the operation of these nanoelectromechanical systems (NEMS) are the actuation and detection of their sub-nanometer displacements at high frequencies. In this Review, we shall focus on this most central concern in NEMS technology: realization of electromechanical transducers at the nanoscale. The currently available techniques to actuate and detect NEMS motion are introduced, and the accuracy, bandwidth, and robustness of these techniques are discussed.

  10. Conduction Electrohydrodynamics with Mobile Electrodes: A Novel Actuation System for Untethered Robots. (United States)

    Cacucciolo, Vito; Shigemune, Hiroki; Cianchetti, Matteo; Laschi, Cecilia; Maeda, Shingo


    Electrohydrodynamics (EHD) refers to the direct conversion of electrical energy into mechanical energy of a fluid. Through the use of mobile electrodes, this principle is exploited in a novel fashion for designing and testing a millimeter-scale untethered robot, which is powered harvesting the energy from an external electric field. The robot is designed as an inverted sail-boat, with the thrust generated on the sail submerged in the liquid. The diffusion constant of the robot is experimentally computed, proving that its movement is not driven by thermal fluctuations, and then its kinematic and dynamic responses are characterized for different applied voltages. The results show the feasibility of using EHD with mobile electrodes for powering untethered robots and provide new evidences for the further development of this actuation system for both mobile robots and compliant actuators in soft robotics.

  11. Fault-tolerant Actuator System for Electrical Steering of Vehicles

    DEFF Research Database (Denmark)

    Sørensen, Jesper Sandberg; Blanke, Mogens


    Being critical to the safety of vehicles, the steering system is required to maintain the vehicles ability to steer until it is brought to halt, should a fault occur. With electrical steering becoming a cost-effective candidate for electrical powered vehicles, a fault-tolerant architecture...... is needed that meets this requirement. This paper studies the fault-tolerance properties of an electrical steering system. It presents a fault-tolerant architecture where a dedicated AC motor design used in conjunction with cheap voltage measurements can ensure detection of all relevant faults...

  12. Pulse Equivalent Area Based Orientation of a Class of Under-Actuated System under Constraints

    Directory of Open Access Journals (Sweden)



    Full Text Available A PEA (Pulse Equivalent Area approach for orientation control of an under actuated pointing device is proposed. The presented work is a sequel to the earlier work done by the authors for the orientation control of the drill machine. The desired orientation is realized through control pulses during specific roll instants. These pulses are generated through single pair of electromagnets mounted on the housing of the pointing device. Due to practical limitation of the system, there is an additional constraint on the actuating signal. The amplitude of the actuating signal is fixed and the Pulse width or duration of the pulse can vary. A discrete equivalent model of pointing device is also developed. A novel approach based on PEA is developed since the exact solution of discrete equivalent model under constraints was not possible. The simulations are included to compare proposed technique with the existing technique developed for similar systems. The performance is also shown under both nominal and parameter variations through Monte Carlo simulations

  13. Robust adaptive fault-tolerant control for leader-follower flocking of uncertain multi-agent systems with actuator failure. (United States)

    Yazdani, Sahar; Haeri, Mohammad


    In this work, we study the flocking problem of multi-agent systems with uncertain dynamics subject to actuator failure and external disturbances. By considering some standard assumptions, we propose a robust adaptive fault tolerant protocol for compensating of the actuator bias fault, the partial loss of actuator effectiveness fault, the model uncertainties, and external disturbances. Under the designed protocol, velocity convergence of agents to that of virtual leader is guaranteed while the connectivity preservation of network and collision avoidance among agents are ensured as well. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  14. Magnetically-Actuated Escherichia coli System for Micro Lithography (United States)

    Lauback, S.; Brown, E.; Pérez-Guzman, L.; Peace, C.; Pierce, C.; Lower, B. H.; Lower, S. K.; Sooryakumar, R.


    Technologies that control matter at the nano- and micro-scale are crucial for developing new engineered materials and devices. While the more traditional approaches for such manipulations often depend on lithographic fabrication, they can be expanded upon by taking advantage of the biological systems within a living cell which also operate on the nano- and micro- scale. In this study, a system is being developed to functionalize a targeted location on the surface of a chip with the protein AmCyan from transformed Escherichia coli cells. Using established methods in molecular biology where a plasmid with the amcyan gene sequence is inserted into the cell, E. coli are engineered to express the AmCyan protein on their outer surface. In order to transport the cells to the targeted location, the transformed E. coli are labeled with superparamagnetic micro-beads which exert directed forces on the cells in an external field. Preliminary results of the protein expression on E. coli, the transport of the cell through weak magnetic fields to targeted locations and the potential to transfer protein from the cell to the chip surface will be presented.

  15. Design of a microelectromechanical systems microgripper with integrated electrothermal actuator and force sensor

    Directory of Open Access Journals (Sweden)

    Sijie Yang


    Full Text Available This article presents the conceptual design of a novel compliant microelectromechanical systems (MEMS-based gripper with integrated electrothermal actuator and electrothermal force sensor. By this design solution, the device possesses some unique characteristics including a small and compact footprint size, and a large driving force by the thermal actuator. Owing to the use of a compliant rotational bearing, a large gripping range is obtained. The sensing arm has a capability of detecting the force transmitted from the left arm so as to prevent the damage of the grasped object. Analytical models are developed to evaluate the statics and dynamics performance of the gripper. Simulation results show that the thermal actuator produces sufficient gripping force to execute the gripping operation with a range of 80 µm under a low input voltage of 6 V. Moreover, the results of the established theoretical models match well with the finite element analysis (FEA simulation results, which verifies the feasibility of the proposed gripper design.

  16. Thermoelectric-Driven Sustainable Sensing and Actuation Systems for Fault-Tolerant Nuclear Incidents

    Energy Technology Data Exchange (ETDEWEB)

    Longtin, Jon [Stony Brook Univ., NY (United States)


    The Fukushima Daiichi nuclear incident in March 2011 represented an unprecedented stress test on the safety and backup systems of a nuclear power plant. The lack of reliable information from key components due to station blackout was a serious setback, leaving sensing, actuation, and reporting systems unable to communicate, and safety was compromised. Although there were several independent backup power sources for required safety function on site, ultimately the batteries were drained and the systems stopped working. If, however, key system components were instrumented with self-powered sensing and actuation packages that could report indefinitely on the status of the system, then critical system information could be obtained while providing core actuation and control during off-normal status for as long as needed. This research project focused on the development of such a self-powered sensing and actuation system. The electrical power is derived from intrinsic heat in the reactor components, which is both reliable and plentiful. The key concept was based around using thermoelectric generators that can be integrated directly onto key nuclear components, including pipes, pump housings, heat exchangers, reactor vessels, and shielding structures, as well as secondary-side components. Thermoelectric generators are solid-state devices capable of converting heat directly into electricity. They are commercially available technology. They are compact, have no moving parts, are silent, and have excellent reliability. The key components to the sensor package include a thermoelectric generator (TEG), microcontroller, signal processing, and a wireless radio package, environmental hardening to survive radiation, flooding, vibration, mechanical shock (explosions), corrosion, and excessive temperature. The energy harvested from the intrinsic heat of reactor components can be then made available to power sensors, provide bi-directional communication, recharge batteries for other

  17. Finite Energy and Bounded Actuator Attacks on Cyber-Physical Systems

    Energy Technology Data Exchange (ETDEWEB)

    Djouadi, Seddik M [ORNL; Melin, Alexander M [ORNL; Ferragut, Erik M [ORNL; Laska, Jason A [ORNL; Dong, Jin [ORNL; Drira, Anis [ORNL


    As control system networks are being connected to enterprise level networks for remote monitoring, operation, and system-wide performance optimization, these same connections are providing vulnerabilities that can be exploited by malicious actors for attack, financial gain, and theft of intellectual property. Much effort in cyber-physical system (CPS) protection has focused on protecting the borders of the system through traditional information security techniques. Less effort has been applied to the protection of cyber-physical systems from intelligent attacks launched after an attacker has defeated the information security protections to gain access to the control system. In this paper, attacks on actuator signals are analyzed from a system theoretic context. The threat surface is classified into finite energy and bounded attacks. These two broad classes encompass a large range of potential attacks. The effect of theses attacks on a linear quadratic (LQ) control are analyzed, and the optimal actuator attacks for both finite and infinite horizon LQ control are derived, therefore the worst case attack signals are obtained. The closed-loop system under the optimal attack signals is given and a numerical example illustrating the effect of an optimal bounded attack is provided.

  18. State and actuator fault estimation observer design integrated in a riderless bicycle stabilization system. (United States)

    Brizuela Mendoza, Jorge Aurelio; Astorga Zaragoza, Carlos Manuel; Zavala Río, Arturo; Pattalochi, Leo; Canales Abarca, Francisco


    This paper deals with an observer design for Linear Parameter Varying (LPV) systems with high-order time-varying parameter dependency. The proposed design, considered as the main contribution of this paper, corresponds to an observer for the estimation of the actuator fault and the system state, considering measurement noise at the system outputs. The observer gains are computed by considering the extension of linear systems theory to polynomial LPV systems, in such a way that the observer reaches the characteristics of LPV systems. As a result, the actuator fault estimation is ready to be used in a Fault Tolerant Control scheme, where the estimated state with reduced noise should be used to generate the control law. The effectiveness of the proposed methodology has been tested using a riderless bicycle model with dependency on the translational velocity v, where the control objective corresponds to the system stabilization towards the upright position despite the variation of v along the closed-loop system trajectories. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  19. Analysis of K-1 fan system for replacement of valve actuator, B Plant/Waste Encapsulation and Storage Facility

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, J.S.


    Components of the K-1 fan system were evaluated for structural adequacy to accommodate an actuator weighing 540 lbs. The components evaluated were the connectors between the actuator and the valve, the duct between the valve and the facility wall, and the stud anchors connecting the duct to the facility wall. The loads were deadload, snow, operating loads, and seismic loads. The components were found to be structurally adequate for these loads.

  20. Magnetic actuators and sensors

    CERN Document Server

    Brauer, John R


    An accessible, comprehensive guide on magnetic actuators and sensors, this fully updated second edition of Magnetic Actuators and Sensors includes the latest advances, numerous worked calculations, illustrations, and real-life applications. Covering magnetics, actuators, sensors, and systems, with updates of new technologies and techniques, this exemplary learning tool emphasizes computer-aided design techniques, especially magnetic finite element analysis, commonly used by today's engineers. Detailed calculations, numerous illustrations, and discussions of discrepancies make this text an inva

  1. Neural adaptive observer-based sensor and actuator fault detection in nonlinear systems: Application in UAV. (United States)

    Abbaspour, Alireza; Aboutalebi, Payam; Yen, Kang K; Sargolzaei, Arman


    A new online detection strategy is developed to detect faults in sensors and actuators of unmanned aerial vehicle (UAV) systems. In this design, the weighting parameters of the Neural Network (NN) are updated by using the Extended Kalman Filter (EKF). Online adaptation of these weighting parameters helps to detect abrupt, intermittent, and incipient faults accurately. We apply the proposed fault detection system to a nonlinear dynamic model of the WVU YF-22 unmanned aircraft for its evaluation. The simulation results show that the new method has better performance in comparison with conventional recurrent neural network-based fault detection strategies. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  2. Optimal Mobile Sensing and Actuation Policies in Cyber-physical Systems

    CERN Document Server

    Tricaud, Christophe


    A successful cyber-physical system, a complex interweaving of hardware and software in direct interaction with some parts of the physical environment, relies heavily on proper identification of the, often pre-existing, physical elements. Based on information from that process, a bespoke “cyber” part of the system may then be designed for a specific purpose. Optimal Mobile Sensing and Actuation Strategies in Cyber-physical Systems focuses on distributed-parameter systems the dynamics of which can be modelled with partial differential equations. Such systems are very challenging to measure, their states being distributed throughout a spatial domain. Consequently, optimal strategies are needed and systematic approaches to the optimization of sensor locations have to be devised for parameter estimation. The text begins by reviewing the newer field of cyber-physical systems and introducing background notions of distributed parameter systems and optimal observation theory. New research opportunities are then de...

  3. Self-powered sensory nerve system for civil structures using hybrid forisome actuators (United States)

    Shoureshi, Rahmat A.; Shen, Amy


    In order to provide a true distributed sensor and control system for civil structures, we have developed a Structural Nervous System that mimics key attributes of a human nervous system. This nervous system is made up of building blocks that are designed based on mechanoreceptors as a fundamentally new approach for the development of a structural health monitoring and diagnostic system that utilizes the recently discovered plant-protein forisomes, a novel non-living biological material capable of sensing and actuation. In particular, our research has been focused on producing a sensory nervous system for civil structures by using forisomes as the mechanoreceptors, nerve fibers, neuronal pools, and spinocervical tract to the nodal and central processing units. This paper will present up to date results of our research, including the design and analysis of the structural nervous system.

  4. Context-aware system for pre-triggering irreversible vehicle safety actuators. (United States)

    Böhmländer, Dennis; Dirndorfer, Tobias; Al-Bayatti, Ali H; Brandmeier, Thomas


    New vehicle safety systems have led to a steady improvement of road safety and a reduction in the risk of suffering a major injury in vehicle accidents. A huge leap forward in the development of new vehicle safety systems are actuators that have to be activated irreversibly shortly before a collision in order to mitigate accident consequences. The triggering decision has to be based on measurements of exteroceptive sensors currently used in driver assistance systems. This paper focuses on developing a novel context-aware system designed to detect potential collisions and to trigger safety actuators even before an accident occurs. In this context, the analysis examines the information that can be collected from exteroceptive sensors (pre-crash data) to predict a certain collision and its severity to decide whether a triggering is entitled or not. A five-layer context-aware architecture is presented, that is able to collect contextual information about the vehicle environment and the actual driving state using different sensors, to perform reasoning about potential collisions, and to trigger safety functions upon that information. Accident analysis is used in a data model to represent uncertain knowledge and to perform reasoning. A simulation concept based on real accident data is introduced to evaluate the presented system concept. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Spherically Actuated Motor (United States)

    Peeples, Steven


    A three degree of freedom (DOF) spherical actuator is proposed that will replace functions requiring three single DOF actuators in robotic manipulators providing space and weight savings while reducing the overall failure rate. Exploration satellites, Space Station payload manipulators, and rovers requiring pan, tilt, and rotate movements need an actuator for each function. Not only does each actuator introduce additional failure modes and require bulky mechanical gimbals, each contains many moving parts, decreasing mean time to failure. A conventional robotic manipulator is shown in figure 1. Spherical motors perform all three actuation functions, i.e., three DOF, with only one moving part. Given a standard three actuator system whose actuators have a given failure rate compared to a spherical motor with an equal failure rate, the three actuator system is three times as likely to fail over the latter. The Jet Propulsion Laboratory reliability studies of NASA robotic spacecraft have shown that mechanical hardware/mechanism failures are more frequent and more likely to significantly affect mission success than are electronic failures. Unfortunately, previously designed spherical motors have been unable to provide the performance needed by space missions. This inadequacy is also why they are unavailable commercially. An improved patentable spherically actuated motor (SAM) is proposed to provide the performance and versatility required by NASA missions.

  6. Fast Sampling Control of Singularly Perturbed Systems with Actuator Saturation and L2 Disturbance

    Directory of Open Access Journals (Sweden)

    Yanzi Miao


    Full Text Available We will consider the problem of fast sampling control for singularly perturbed systems subject to actuator saturation and L2 disturbance. A sufficient condition for the existence of a state feedback controller is proposed. Under this controller, the boundedness of the trajectories in the presence of L2 disturbances is guaranteed for any singular perturbation parameter less than or equal to a predefined upper bound. To improve the capacity of disturbance tolerance and disturbance rejection, two convex optimization problems are formulated. Finally, a numerical example is presented to demonstrate the effectiveness of the main results of this paper.

  7. Intelligent Control Electromagnetic Actuated Continuously Variable Transmission System for Passenger Car (United States)

    Rahman, Ataur; Sharif, Sazzad; Mohiuddin, AKM; Faris Ismail, Ahmed; Izan, Sany Ihsan


    Continuously variable transmission (CVT) system transmits the engine /battery power to the car driving wheel smoothly and efficiently. Cars with CVT produces some noise and slow acceleration to meet the car power demand on initial start-ups and slow speed. The car noise is produced as a result of CVT adjustment the engine speed with the hydraulic pressure. The current CVT problems incurred due to the slow response of hydraulic pressure and CVT fluid viscosity due to the development of heat.The aim of this study is to develop electromagnetic actuated CVT (EMA-CVT) with intelligent switching controlling system (ICS). The experimental results of ¼ scale EMA shows that it make the acceleration time of the car in 3.5-5 sec which is 40% less than the hydraulic CVT in the market. The EMA develops the electromagnetic force in the ranged of 350 -1200 N for the supply current in the range of 10-15 amp. This study introduced fuzzy intelligent system (FIS) to predict the EMA system dynamic behaviour in order to identify the current control for the EMA actuation during operation of the CVT. It is expecting that the up scale EMA-CVT would reduce the 75% of vehicle power transmission loss by accelerating vehicle in 5 sec and save the IC engine power consumption about 20% which will makes the vehicle energy efficient (EEV) and reduction of green house gas reduction.

  8. Exponential stabilisation for time-varying delay system with actuator faults: an average dwell time method (United States)

    Wang, Limin; Shao, Cheng


    The issue of exponential stabilisation for a class of special time-varying delay switched systems resulting from actuator faults is considered in this article. The time-varying delay is assumed to belong to an interval and can be a slow or fast time-varying function. A hybrid state feedback strategy is redesigned to guarantee the system stable since the original controller is unavailable for some actuators failures. A class of switching laws incorporating the average dwell time method is proposed so that the special switched system with interval time-varying delay is exponentially stable. New delay-range-dependent stabilisation conditions using state feedback controllers are formulated in terms of linear matrix inequalities (LMIs) by choosing appropriate Lyapunov-Krasovskii functional without neglecting some useful knowledge on system states. Parameterised characterisations of the controllers are given in terms of the feasibility solutions to the LMIs. Two numeral examples are given to demonstrate the applicability and the effectiveness of the proposed method.

  9. Magnetically Actuated Seal (United States)

    Pinera, Alex


    This invention is a magnetically actuated seal in which either a single electromagnet, or multiple electromagnets, are used to control the seal's position. This system can either be an open/ close type of system or an actively controlled system.

  10. Active Vibration Control in a Rotor System by an Active Suspension with Linear Actuators

    Directory of Open Access Journals (Sweden)

    M. Arias-Montiel


    Full Text Available In this paper the problem of modeling, analysis and unbalance response control of a rotor system with two disks in an asymmetrical configuration is treated. The Finite Element Method (FEM is used to get the system model including the gyroscopic effects and then, the obtained model is experimentally validated. Rotordynamic analysis is carried out using the finite element model obtaining the Campbell diagram, the natural frequencies and the critical speeds of the rotor system. An asymptotic observer is designed to estimate the full state vector which is used to synthesize a Linear Quadratic Regulator (LQR to reduce the vibration amplitudes when the system passes through the first critical speed. Some numerical simulations are carried out to verify the closed-loop system behavior. The active vibration control scheme is experimentally validated using an active suspension with electromechanical linear actuators, obtaining significant reductions in the resonant peak.

  11. Tracking control of a multilayer piezoelectric actuator using a fiber bragg grating displacement sensor system. (United States)

    Chuang, Kuo-Chih; Ma, Chien-Ching


    This paper provides a fiber Bragg grating (FBG) sensor system which can measure the point-wise, out-of-plane displacement to examine the position-tracking control problem of a multilayer piezoelectric actuator (MPA). An FBG filter-based wavelength-optical intensity modulation technique is used in this study. A nominal system model is identified experimentally from the responses excited by random signals measured by an FBG displacement sensor that are simultaneously compared with those obtained from a laser Doppler vibrometer. To further investigate the sensing ability of the proposed system in a feedback control problem, control strategies including robust H(infinity) control, proportional-integralderivative control, and pseudoderivative feedback control are implemented. The characteristics of the step responses for each controller are examined. The experimental results show that the proposed sensor system is capable of performing the system identification and can serve as a feedback control sensor which has a displacement sensitivity of 5 mV/nm.

  12. Dynamic Characteristics of a Hydraulic Amplification Mechanism for Large Displacement Actuators Systems

    Directory of Open Access Journals (Sweden)

    Xavier Arouette


    Full Text Available We have developed a hydraulic displacement amplification mechanism (HDAM and studied its dynamic response when combined with a piezoelectric actuator. The HDAM consists of an incompressible fluid sealed in a microcavity by two largely deformable polydimethylsiloxane (PDMS membranes. The geometry with input and output surfaces having different cross-sectional areas creates amplification. By combining the HDAM with micro-actuators, we can amplify the input displacement generated by the actuators, which is useful for applications requiring large deformation, such as tactile displays. We achieved a mechanism offering up to 18-fold displacement amplification for static actuation and 12-fold for 55 Hz dynamic actuation.

  13. Neural network-based robust actuator fault diagnosis for a non-linear multi-tank system. (United States)

    Mrugalski, Marcin; Luzar, Marcel; Pazera, Marcin; Witczak, Marcin; Aubrun, Christophe


    The paper is devoted to the problem of the robust actuator fault diagnosis of the dynamic non-linear systems. In the proposed method, it is assumed that the diagnosed system can be modelled by the recurrent neural network, which can be transformed into the linear parameter varying form. Such a system description allows developing the designing scheme of the robust unknown input observer within H∞ framework for a class of non-linear systems. The proposed approach is designed in such a way that a prescribed disturbance attenuation level is achieved with respect to the actuator fault estimation error, while guaranteeing the convergence of the observer. The application of the robust unknown input observer enables actuator fault estimation, which allows applying the developed approach to the fault tolerant control tasks. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  14. Design, fabrication, and test planning for an SMA-actuated vortex wake control system (United States)

    Quackenbush, Todd R.; Batcho, P. F.; Bilanin, Alan J.; Carpenter, Bernie F.


    This paper describes ongoing design and fabrication work on a vortex wake control system for submarines that employs SMA-actuated devices. Previous work has described the theoretical basis and feasibility studies for this system, which is based on a novel wake control scheme known as vortex leveraging. The critical item in the realization of this system is a Smart Vortex Leveraging Tab (SVLT), whose design and fabrication is the principal focus of this work. This paper outlines the background of the effort and the design principles involved, but will chiefly deal with three closely interrelated topics; the hydrodynamic design requirements and control surface layout for the vortex leveraging system; the detail design and fabrication techniques being used in the construction of a prototype SVLT; and the test planning and experiment design process currently underway for test of both the overall vortex leveraging concept and SVLT device itself.

  15. Smart Control of Multiple Evaporator Systems with Wireless Sensor and Actuator Networks

    Directory of Open Access Journals (Sweden)

    Apolinar González-Potes


    Full Text Available This paper describes the complete integration of a fuzzy control of multiple evaporator systems with the IEEE 802.15.4 standard, in which we study several important aspects for this kind of system, like a detailed analysis of the end-to-end real-time flows over wireless sensor and actuator networks (WSAN, a real-time kernel with an earliest deadline first (EDF scheduler, periodic and aperiodic tasking models for the nodes, lightweight and flexible compensation-based control algorithms for WSAN that exhibit packet dropouts, an event-triggered sampling scheme and design methodologies. We address the control problem of the multi-evaporators with the presence of uncertainties, which was tackled through a wireless fuzzy control approach, showing the advantages of this concept where it can easily perform the optimization for a set of multiple evaporators controlled by the same smart controller, which should have an intelligent and flexible architecture based on multi-agent systems (MAS that allows one to add or remove new evaporators online, without the need for reconfiguring, while maintaining temporal and functional restrictions in the system. We show clearly how we can get a greater scalability, the self-configuration of the network and the least overhead with a non-beacon or unslotted mode of the IEEE 802.15.4 protocol, as well as wireless communications and distributed architectures, which could be extremely helpful in the development process of networked control systems in large spatially-distributed plants, which involve many sensors and actuators. For this purpose, a fuzzy scheme is used to control a set of parallel evaporator air-conditioning systems, with temperature and relative humidity control as a multi-input and multi-output closed loop system; in addition, a general architecture is presented, which implements multiple control loops closed over a communication network, integrating the analysis and validation method for multi

  16. Nonmagnetic driver for piezoelectric actuators

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh


    Piezoelectric actuator drive aims to enable reliable motor performance in strong magnetic fields for magnetic res- onance imaging and computed tomography treatment tables. There are technical limitations in operation of these motors and drive systems related to magnetic interference. Piezoelectric...... actuators. Therefore, piezoelectric transformer-based power converters are used for driving piezoelectric actuator drive motor in the presence of high electromagnetic field....

  17. Creep-Fatigue Relationsihps in Electroactive Polymer Systems and Predicted Effects in an Actuator Design (United States)

    Vinogradov, Aleksandra M.; Ihlefeld, Curtis M.; Henslee, Issac


    The paper concerns the time-dependent behavior of electroactive polymers (EAP) and their use in advanced intelligent structures for space exploration. Innovative actuator design for low weight and low power valves required in small plants planned for use on the moon for chemical analysis is discussed. It is shown that in-depth understanding of cyclic loading effects observed through accelerated creep rates due to creep-fatigue interaction in polymers is critical in terms of proper functioning of EAP based actuator devices. In the paper, an overview of experimental results concerning the creep properties and cyclic creep response of a thin film piezoelectric polymer polyvinylidene fluoride (PVDF) is presented. The development of a constitutive creep-fatigue interaction model to predict the durability and service life of electroactive polymers is discussed. A novel method is proposed to predict damage accumulation and fatigue life of polymers under oyclic loading conditions in the presence of creep. The study provides a basis for ongoing research initiatives at the NASA Kennedy Space Center in the pursuit of new technologies using EAP as active elements for lunar exploration systems.

  18. Crane system with remote actuation mechanism for use in argon compartment in ACPF hot cell

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Kwang, E-mail:; Park, Byung-Suk; Yu, Seung-Nam; Kim, Kiho; Cho, Il-je


    Highlights: • Novel crane system with a remote actuation mechanism for feasible maintenance under limited space conditions is proposed. • Linear drive systems are implemented for accurate positioning. • Modular design concepts for easy maintenance are introduced. • The motion controller and the off-the-shelf camera controller are integrated to provide more efficient operation. - Abstract: The Advanced spent fuel Conditioning Process Facility (ACPF) at the Korea Atomic Energy Research Institute (KAERI) has recently been successfully renovated. One of the highlights of this renovation project was the installation of a small argon compartment within the atmospheric hot cell of the facility. Even though a crane system was considered necessary for the remote handling of the processing equipment inside the argon compartment, no suitable commercial cranes were available. This was because a limited amount of space had been reserved for the installation of the crane. Moreover, a master-slave manipulator (MSM), the only available means of maintenance of the crane, was unable to reach it in the limited workspace. To address the difficulties in the design of this crane, in this study, a remote actuation mechanism is devised where the mechanical and electrical parts of the crane system are separated, positioned far away from each other, and connected through power transmission shafts. This approach has two main advantages. First, the electrical parts can be placed inside the workspace of the MSM, hence allowing for remote maintenance. Second, the space occupied by the electrical parts and their cables, which are separate from the crane in the proposed design, can be considered and exploited in designing the mechanical parts of the crane. This enables the construction of a short, special crane in order to maximize the workspace. Furthermore, the mechanical parts for the MSM located outside the workspace are designed to possess a high safety margin to ensure durability

  19. Adaptive Robust Actuator Fault Accommodation for a Class of Uncertain Nonlinear Systems with Unknown Control Gains

    Directory of Open Access Journals (Sweden)

    Yuefei Wu


    Full Text Available An adaptive robust fault tolerant control approach is proposed for a class of uncertain nonlinear systems with unknown signs of high-frequency gain and unmeasured states. In the recursive design, neural networks are employed to approximate the unknown nonlinear functions, K-filters are designed to estimate the unmeasured states, and a dynamical signal and Nussbaum gain functions are introduced to handle the unknown sign of the virtual control direction. By incorporating the switching function σ algorithm, the adaptive backstepping scheme developed in this paper does not require the real value of the actuator failure. It is mathematically proved that the proposed adaptive robust fault tolerant control approach can guarantee that all the signals of the closed-loop system are bounded, and the output converges to a small neighborhood of the origin. The effectiveness of the proposed approach is illustrated by the simulation examples.

  20. Development of damage monitoring system for aircraft structure using a PZT actuator/FBG sensor hybrid system (United States)

    Ogisu, Toshimichi; Shimanuki, Masakazu; Kiyoshima, Satoshi; Okabe, Yoji; Takeda, Nobuo


    This paper presents a part of the research results on a damage monitoring system using PZT actuators/FBG sensors for advanced composite material structures of new-generation aircrafts. To achieve weight reduction of the aircraft structure, these advanced composite materials have gradually been employed for the primary structure. It is expected that when these materials are extensively employed, an efficient bonded structure such as a hat-shaped stringer will be utilized for the aircraft structure. However, these bonded structures have critical problems such as debonding and delamination at the interfaces of the laminate. Further, a single-step molding process of the structure elements is necessary in order to ensure low cost and thus affordability. However, this low-cost process results in an increase in the non-destructive inspection (NDI) cost. Therefore, an innovative damage monitoring system is required for structural health management. In the present study, the authors have developed a hybrid sensor system that can detect the elastic waves launched from the piezo transducer (PZT) actuator using a high-speed and high-accuracy fiber Bragg grating (FBG) sensor to resolve the issues mentioned above. In this study, the conceptual design of an aircraft that can employ this damage monitoring system was carried out. Subsequently, the application area was selected based on cases of certain kinds of damage. Further, the validity of the damage monitoring system for the verification of the structural integrity of the aircraft was discussed. Next, in order to verify the elastic wave detectability of the FBG sensor, it was confirmed that an elastic wave of 300 kHz is detectable at a distance of 5 cm between the PZT actuator and FBG sensor using an aluminum sheet and CFRP cross-ply laminate and also by considering the relationship between sensor length and sensitivity. Through the present research results, the possibility of applying the damage monitoring system to the

  1. Robust vibration control at critical resonant modes using indirect-driven self-sensing actuation in mechatronic systems. (United States)

    Hong, Fan; Pang, Chee Khiang


    This paper presents an improved indirect-driven self-sensing actuation circuit for robust vibration control of piezoelectrically-actuated flexible structures in mechatronic systems. The circuit acts as a high-pass filter and provides better self-sensing strain signals with wider sensing bandwidth and higher signal-to-noise ratio. An adaptive non-model-based control is used to compensate for the structural vibrations using the strain signals from the circuit. The proposed scheme is implemented in a PZT-actuated suspension of a commercial dual-stage hard disk drive. Experimental results show improvements of 50% and 75% in the vibration suppression at 5.4kHz and 21kHz respectively, compared to the conventional PI control. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  2. Model-based design and experimental verification of a monitoring concept for an active-active electromechanical aileron actuation system (United States)

    Arriola, David; Thielecke, Frank


    Electromechanical actuators have become a key technology for the onset of power-by-wire flight control systems in the next generation of commercial aircraft. The design of robust control and monitoring functions for these devices capable to mitigate the effects of safety-critical faults is essential in order to achieve the required level of fault tolerance. A primary flight control system comprising two electromechanical actuators nominally operating in active-active mode is considered. A set of five signal-based monitoring functions are designed using a detailed model of the system under consideration which includes non-linear parasitic effects, measurement and data acquisition effects, and actuator faults. Robust detection thresholds are determined based on the analysis of parametric and input uncertainties. The designed monitoring functions are verified experimentally and by simulation through the injection of faults in the validated model and in a test-rig suited to the actuation system under consideration, respectively. They guarantee a robust and efficient fault detection and isolation with a low risk of false alarms, additionally enabling the correct reconfiguration of the system for an enhanced operational availability. In 98% of the performed experiments and simulations, the correct faults were detected and confirmed within the time objectives set.

  3. Piezoelectric actuators in the active vibration control system of journal bearings (United States)

    Tůma, J.; Šimek, J.; Mahdal, M.; Pawlenka, M.; Wagnerova, R.


    The advantage of journal hydrodynamic bearings is high radial load capacity and operation at high speeds. The disadvantage is the excitation of vibrations, called an oil whirl, after crossing a certain threshold of the rotational speed. The mentioned vibrations can be suppressed using the system of the active vibration control with piezoactuators which move the bearing bushing. The motion of the bearing bushing is controlled by a feedback controller, which responds to the change in position of the bearing journal which is sensed by a pair of capacitive sensors. Two stacked linear piezoactuators are used to actuate the position of the bearing journal. This new bearing enables not only to damp vibrations but also serves to maintain the desired bearing journal position with an accuracy of micrometers. The paper will focus on the effect of active vibration control on the performance characteristics of the journal bearing.

  4. Test results for an SMA-actuated vortex wake control system (United States)

    Quackenbush, Todd R.; Bilanin, Alan J.; Carpenter, Bernie F.


    This paper describes recent test result obtained on a prototype SMA-actuated foil that serves as a key element in a vortex wake control scheme for lifting surfaces. Previous papers have described the theoretical basis and feasibility studies for this scheme - which is based on a novel wake control known as vortex leveraging - as well as prior work on device design, test planning, and fabrication. The critical item in the realization of this scheme is a Smart Vortex Leveraging Tab (SVLT), a device designed to provide perturbations in the vortex system downstream of lifting surfaces at frequencies and amplitudes carefully selected to accelerate overall wake breakup. The paper summarizes the background of the effort, but focuses on the detail design and fabrication techniques used in the construction of a prototype SVLT and the results of water tunnel tests of a near full-scale prototype device.

  5. Parametric Design and Multiobjective Optimization of Maglev Actuators for Active Vibration Isolation System

    Directory of Open Access Journals (Sweden)

    Qianqian Wu


    Full Text Available The microvibration has a serious impact on science experiments on the space station and on image quality of high resolution satellites. As an important component of the active vibration isolation platform, the maglev actuator has a large stroke and exhibits excellent isolating performance benefiting from its noncontact characteristic. A maglev actuator with good linearity was designed in this paper. Fundamental features of the maglev actuator were obtained by finite element simulation. In order to minimize the coil weight and the heat dissipation of the maglev actuator, parametric design was carried out and multiobjective optimization based on the genetic algorithm was adopted. The optimized actuator has better mechanical properties than the initial one. Active vibration isolation platforms for different-scale payload were designed by changing the arrangement of the maglev actuators. The prototype to isolate vibration for small-scale payload was manufactured and the experiments for verifying the characteristics of the actuators were set up. The linearity of the actuator and the mechanical dynamic response of the vibration isolation platform were obtained. The experimental results highlight the effectiveness of the proposed design.

  6. Apparatus, system, and method for providing fabric-elastomer composites as pneumatic actuators

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Ramses V.; Whitesides, George M.


    Soft pneumatic actuators based on composites consisting of elastomers with embedded sheet or fiber structures (e.g., paper or fabric) that are flexible but not extensible are described. On pneumatic inflation, these actuators move anisotropically, based on the motions accessible by their composite structures. They are inexpensive, simple to fabricate, light in weight, and easy to actuate. This class of structure is versatile: the same principles of design lead to actuators that respond to pressurization with a wide range of motions (bending, extension, contraction, twisting, and others). Paper, when used to introduce anisotropy into elastomers, can be readily folded into three-dimensional structures following the principles of origami; these folded structures increase the stiffness and anisotropy of the elastomeric actuators, while keeping them light in weight.

  7. Automated stopcock actuator


    Vandehey, N. T.; O\\'Neil, J. P.


    Introduction We have developed a low-cost stopcock valve actuator for radiochemistry automation built using a stepper motor and an Arduino, an open-source single-board microcontroller. The con-troller hardware can be programmed to run by serial communication or via two 5–24 V digital lines for simple integration into any automation control system. This valve actuator allows for automated use of a single, disposable stopcock, providing a number of advantages over stopcock manifold systems ...

  8. Pneumatic actuated robotic assistant system for aortic valve replacement under MRI guidance. (United States)

    Li, Ming; Kapoor, Ankur; Mazilu, Dumitru; Horvath, Keith A


    We present a pneumatic actuated robotic assistant system for transapical aortic valve replacement under MRI guidance in a beating heart. This is a minimally invasive procedure that is currently performed manually inside the MRI bore. A robotic assistance system that integrates an interactive real-time MRI system, a robotic arm with a newly developed robotic valve delivery module, as well as user interfaces for the physician to plan the procedure and manipulate the robot, would be advantageous for the procedure. An Innomotion arm with hands-on cooperative interface was used as a device holder. A compact MRI compatible robotic delivery module was developed for delivering both balloon-expandable and self-expanding prostheses. A compact fiducial that can be placed close to the volume of interest and requires a single image plane was used for image-based robot registration. The system provides different user interfaces at various stages of the procedure. We present the development and evaluation of the components and the system in ex-vivo experiments.

  9. Modified Denavit-Hartenberg Coordinate System for Robot Actuating Mechanisms with Tree-like Kinematic Structure

    Directory of Open Access Journals (Sweden)

    A. K. Kovalchuk


    Full Text Available To build mathematical models of actuating mechanisms (AM of robots with linear kinematic structure, J. Denavit and R.S. Hartenberg (D-H proposed to use a special coordinate system (CS. It uses a matrix of homogeneous transformation and provides clear and unambiguous rules to build mathematical models of robot actuating mechanisms. Developers widely use this approach because of its clarity and binding to AM design parameters. However, its use to describe robots the AM of which has a spatial tree-like kinematic structure revealed the certain hardship.The paper offers a method for building a modified D-H coordinate system. Its using allows to create mathematical models of robot AM, having spatial kinematic structure. The method is based on using both the graphs theory and the known D-H coordinate system jointly.The paper defines concepts of main and auxiliary coordinate systems and the order of their location on the tree-like AM. The values of the modified parameters of D-H are obtained. There its known parameters are complemented by parameters f(i, which determine the father number of the link i, and ns(i, that shows, which son in succession is the link i for the link f(i. An algorithm to form the matrix of reachability and the graph of reachability of the tree-like AM is proposed.It is proved that the use of the modified D-H coordinate system allows us to record in a block-matrix form both kinematic and dynamic equations for all links of the tree-like AM of robot. The use of these equations together with D'Alembert principle allowed us to write the equations of the tree-like AM dynamics of robot in the form traditional for recording the AM dynamics equations with open kinematic structure.Via examples of mathematically described kinematics and dynamics of tree-like AM of specific robots (robot-dog, robot-crab, anthropomorphic walking robot, etc. the paper shows efficiency of modified D-H coordinate system.Obtained research results of the medical

  10. Closed-loop helium circulation system for actuation of a continuously operating heart catheter pump. (United States)

    Karabegovic, Alen; Hinteregger, Markus; Janeczek, Christoph; Mohl, Werner; Gföhler, Margit


    Currently available, pneumatic-based medical devices are operated using closed-loop pulsatile or open continuous systems. Medical devices utilizing gases with a low atomic number in a continuous closed loop stream have not been documented to date. This work presents the construction of a portable helium circulation addressing the need for actuating a novel, pneumatically operated catheter pump. The design of its control system puts emphasis on the performance, safety and low running cost of the catheter pump. Static and dynamic characteristics of individual elements in the circulation are analyzed to ensure a proper operation of the system. The pneumatic circulation maximizes the working range of the drive unit inside the catheter pump while reducing the total size and noise production.Separate flow and pressure controllers position the turbine's working point into the stable region of the pressure creation element. A subsystem for rapid gas evacuation significantly decreases the duration of helium removal after a leak, reaching subatmospheric pressure in the intracorporeal catheter within several milliseconds. The system presented in the study offers an easy control of helium mass flow while ensuring stable behavior of its internal components.

  11. Modeling and motion compensation of a bidirectional tendon-sheath actuated system for robotic endoscopic surgery. (United States)

    Sun, Zhenglong; Wang, Zheng; Phee, Soo Jay


    Recent study shows that tendon-sheath system (TSS) has great potential in the development of surgical robots for endoscopic surgery. It is able to deliver adequate power in a light-weight and compact package. And the flexibility and compliance of the tendon-sheath system make it capable of adapting to the long and winding path in the flexible endoscope. However, the main difficulties in precise control of such system fall on the nonlinearities of the system behavior and absence of necessary sensory feedback at the surgical end-effectors. Since accurate position control of the tool is a prerequisite for efficacy, safety and intuitive user-experience in robotic surgery, in this paper we propose a system modeling approach for motion compensation. Based on a bidirectional actuated system using two separate tendon-sheaths, motion transmission is firstly characterized. Two types of positional errors due to system backlash and environment loading are defined and modeled. Then a model-based feedforward compensation method is proposed for open-loop control, giving the system abilities to adjust according to changes in the transmission route configuration without any information feedback from the distal end. A dedicated experimental platform emulating a bidirectional TSS robotic system for endoscopic surgery is built for testing. Proposed positional errors are identified and verified. The performance of the proposed motion compensation is evaluated by trajectory tracking under different environment loading conditions. And the results demonstrate that accurate position control can be achieved even if the transmission route configuration is updated. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Development of an Upper Limb Power Assist System Using Pneumatic Actuators for Farming Lift-up Motion (United States)

    Yagi, Eiichi; Harada, Daisuke; Kobayashi, Masaaki

    A power assist system has lately attracted considerable attention to lifting-up an object without low back pain. We have been developing power assist systems with pneumatic actuators for the elbow and shoulder to farming support of lifting-up a bag of rice weighing 30kg. This paper describes the mechanism and control method of this power assist system. The pneumatic rotary actuator supports shoulder motion, and the air cylinder supports elbow motion. In this control method, the surface electromyogram(EMG) signals are used as input information of the controller. The joint support torques of human are calculated based on the antigravity term of necessary joint torques, which are estimated on the dynamics of a human approximated link model. The experimental results show the effectiveness of the proposed mechanism and control method of the power assist system.

  13. Monolithic integrated system with an electrowetting-on-dielectric actuator and a film-bulk-acoustic-resonator sensor (United States)

    Zhang, Menglun; Cui, Weiwei; Chen, Xuejiao; Wang, Chao; Pang, Wei; Duan, Xuexin; Zhang, Daihua; Zhang, Hao


    Although digital microfluidics has shown great potential in a wide range of applications, a lab-on-a-chip with integrated digital droplet actuators and powerful biochemical sensors is still lacking. To address the demand, a fully integrated chip with electrowetting-on-dielectric (EWOD) and a film bulk acoustic resonator (FBAR) sensor is introduced, where an EWOD actuator manipulates digital droplets and the FBAR sensor detects the presence of substances in the droplets, respectively. The piezoelectric layer of the FBAR sensor and the dielectric layer of the EWOD share the same aluminum nitride (AlN) thin film, which is a key factor to achieve the full integration of the two completely different devices. The liquid droplets are reliably managed by the EWOD actuator to sit on or move off the FBAR sensor precisely. Sessile drop experiments and limit of detection (LOD) experiments are carried out to characterize the EWOD actuator and the FBAR sensor, respectively. Taking advantage of the digital droplet operation, a ‘dry sensing mode’ of the FBAR sensor in the lab-on-a-chip microsystem is proposed, which has a much higher signal to noise ratio than the conventional ‘wet sensing mode’. Hg2+ droplets with various concentrations are transported and sensed to demonstrate the capability of the integrated system. The EWOD-FBAR chip is expected to play an important role in many complex lab-on-a-chip applications.

  14. Linear Extended State Observer-Based Motion Synchronization Control for Hybrid Actuation System of More Electric Aircraft. (United States)

    Wang, Xingjian; Liao, Rui; Shi, Cun; Wang, Shaoping


    Moving towards the more electric aircraft (MEA), a hybrid actuator configuration provides an opportunity to introduce electromechanical actuator (EMA) into primary flight control. In the hybrid actuation system (HAS), an electro-hydraulic servo actuator (EHSA) and an EMA operate on the same control surface. In order to solve force fighting problem in HAS, this paper proposes a novel linear extended state observer (LESO)-based motion synchronization control method. To cope with the problem of unavailability of the state signals required by the motion synchronization controller, LESO is designed for EHSA and EMA to observe the state variables. Based on the observed states of LESO, motion synchronization controllers could enable EHSA and EMA to simultaneously track the desired motion trajectories. Additionally, nonlinearities, uncertainties and unknown disturbances as well as the coupling term between EHSA and EMA can be estimated and compensated by using the extended state of the proposed LESO. Finally, comparative simulation results indicate that the proposed LESO-based motion synchronization controller could reduce significant force fighting between EHSA and EMA.

  15. The UC Softhand: Light Weight Adaptive Bionic Hand with a Compact Twisted String Actuation System

    Directory of Open Access Journals (Sweden)

    Mahmoud Tavakoli


    Full Text Available In this paper, we present the design and development of the UC-Softhand. The UC Softhand is a low cost, Bionic and adaptive hand that takes advantage of compliant joints. By optimization of the actuation strategy as well as the actuation mechanism, we could develop an anthropomorphic hand that embeds three actuators, transmission mechanisms, controllers and drivers in the palm of the hand, and weighs only 280 g, making it one of the lightest bionic hands that has been created so far. The key aspect of the UC Softhand is utilization of a novel compact twisted string actuation mechanism, that allows a considerable weight and cost reduction compared to its predecessor.

  16. A Diagnostic Approach for Electro-Mechanical Actuators in Aerospace Systems (United States)

    National Aeronautics and Space Administration — Electro-mechanical actuators (EMA) are finding increasing use in aerospace applications, especially with the trend towards all all-electric aircraft and spacecraft...

  17. Experimental and Analytical Development of a Health Management System for Electro-Mechanical Actuators (United States)

    National Aeronautics and Space Administration — Expanded deployment of Electro-Mechanical Actuators (EMAs) in critical applications has created much interest in EMA Prognostic Health Management (PHM), a key...

  18. Experimental Validation of a Prognostic Health Management System for Electro-Mechanical Actuators (United States)

    National Aeronautics and Space Administration — The work described herein is aimed to advance prognostic health management solutions for electro-mechanical actuators and, thus, increase their reliability and...

  19. Chapter 2. Mode-switching in Hydraulic Actuator Systems - An Experiment

    DEFF Research Database (Denmark)

    Andersen, Torben Ole; Conrad, Finn; Ravn, Anders P.


    Experiments with mode-switching adaptive control of actuators to drive a hydraulic test robot.The research is a cooperation with IT, DTU within the IMCIA Research Programme supported by the Danish Technical Research Council, STVF.......Experiments with mode-switching adaptive control of actuators to drive a hydraulic test robot.The research is a cooperation with IT, DTU within the IMCIA Research Programme supported by the Danish Technical Research Council, STVF....

  20. Near-surface gravity actuated pipe (GAP{sup TM}) system for Brazilian deepwater fluid transfer

    Energy Technology Data Exchange (ETDEWEB)

    Fromage, Lionel; Brown, Paul A. [SBM Offshore (Monaco)


    The recent discovery of new deep water and ultra-deep water oil and gas fields offshore Brazil, including pre-salt reservoirs, has become a focal point for field development Operators and Contractors. The aggressive nature of fluids (sour, high density) in combination with deeper waters implies potential flow assurance issues. These issues challenge riser and pipeline technology to find cost effective solutions for hydrocarbon fluid transfer in field development scenarios involving phased tied-back. The near-surface GAP{sup TM}, system (Gravity Actuated Pipe{sup TM}), which has been in operation for more than two years on the Kikeh field offshore Malaysia in 1325 m of water between a Dry Tree Unit (SPAR) and a turret-moored FPSO, is considered to meet these challenges since such a product is quasi independent of water depth and takes advantage of being near surface to optimize flow assurance. Furthermore the GAP{sup TM} has undergone technical upgrades when compared to the Kikeh project in order to make it suitable for the more hostile met ocean conditions offshore Brazil. This paper presents the design features, the construction and assembly plans in Brazil and the offshore installation of a GAP fluid transfer system for operation in Brazilian deep waters. (author)

  1. Piezoelectrically Actuated Robotic System for MRI-Guided Prostate Percutaneous Therapy. (United States)

    Su, Hao; Shang, Weijian; Cole, Gregory; Li, Gang; Harrington, Kevin; Camilo, Alexander; Tokuda, Junichi; Tempany, Clare M; Hata, Nobuhiko; Fischer, Gregory S


    This paper presents a fully-actuated robotic system for percutaneous prostate therapy under continuously acquired live magnetic resonance imaging (MRI) guidance. The system is composed of modular hardware and software to support the surgical workflow of intra-operative MRI-guided surgical procedures. We present the development of a 6-degree-of-freedom (DOF) needle placement robot for transperineal prostate interventions. The robot consists of a 3-DOF needle driver module and a 3-DOF Cartesian motion module. The needle driver provides needle cannula translation and rotation (2-DOF) and stylet translation (1-DOF). A custom robot controller consisting of multiple piezoelectric motor drivers provides precision closed-loop control of piezoelectric motors and enables simultaneous robot motion and MR imaging. The developed modular robot control interface software performs image-based registration, kinematics calculation, and exchanges robot commands and coordinates between the navigation software and the robot controller with a new implementation of the open network communication protocol OpenIGTLink. Comprehensive compatibility of the robot is evaluated inside a 3-Tesla MRI scanner using standard imaging sequences and the signal-to-noise ratio (SNR) loss is limited to 15%. The image deterioration due to the present and motion of robot demonstrates unobservable image interference. Twenty-five targeted needle placements inside gelatin phantoms utilizing an 18-gauge ceramic needle demonstrated 0.87 mm root mean square (RMS) error in 3D Euclidean distance based on MRI volume segmentation of the image-guided robotic needle placement procedure.

  2. Vertical comb drive actuator for the measurement of piezoelectric coefficients in small-scale systems (United States)

    Wooldridge, J.; Muniz-Piniella, A.; Stewart, M.; Shean, T. A. V.; Weaver, P. M.; Cain, M. G.


    A micro-electro-mechanical systems (MEMS) vertical levitation comb drive actuator has been created for the measurement of piezoelectric coefficients in thin/thick films or piezoelectrically active micro-scale components of other MEMS devices. The device exerts a dynamic force of 33 μN at an applied voltage of 100 V. The charge developed on the piezoelectric test device is measured using a charge sensitive pre-amplifier and lock-in technique, enabling measurements down to 1×10-5 pC. The system was tested with ten different piezoelectric samples with coefficients in the range 70-1375 pC N-1 and showed a good correlation (r = 0.9997) to measurements performed with macroscopic applied stresses, and piezoelectric impedance resonance techniques. The measurement of the direct piezoelectric effect in micro- and nano-scale piezo-materials has been made possible using MEMS processing technology. This new application of a MEMS metrology device has been developed and fully characterized in order to accurately evaluate the functional properties of piezoelectric materials at the scale required in micro- to nano-scale applications.

  3. High-speed horizontal-path atmospheric turbulence correction with a large-actuator-number microelectromechanical system spatial light modulator in an interferometric phase-conjugation engine. (United States)

    Baker, K L; Stappaerts, E A; Gavel, D; Wilks, S C; Tucker, J; Silva, D A; Olsen, J; Olivier, S S; Young, P E; Kartz, M W; Flath, L M; Kruelevitch, P; Crawford, J; Azucena, Oscar


    Results of atmospheric propagation for a high-speed, large-actuator-number adaptive optics system are presented. The system uses a microelectromechanical system- (MEMS-) based spatial light modulator correction device with 1024 actuators. Tests over a 1.35-km path achieved correction speeds in excess of 800 Hz and Strehl ratios close to 0.5. The wave-front sensor was based on a quadrature interferometer that directly measures phase. This technique does not require global wave-front reconstruction, making it relatively insensitive to scintillation and phase residues. The results demonstrate the potential of large-actuator-number MEMS-based spatial light modulators to replace conventional deformable mirrors.

  4. Nonlinear Aeroelastic Behavior of Tail / Rudder Systems with Freeplay and Actuator Failure (United States)

    Noble, Matthew

    This thesis discusses the development of numerical simulations implemented in MATLAB and of an experimental tail/rudder model for the investigation of the effects of non-linearities on control surface flutter of a three-degree of freedom typical section airfoil. Non-linearities investigated include a structural non-linearity in the form of freeplay about the control surface hinge line as well as velocity-squared damping, simulating a failed actuator. The mathematical modeling, design, and testing of a prototype velocity-squared damper is also presented for use in the numerical simulations. In both cases, the describing function method has been used to predict the amplitudes of possible Limit-Cycle Oscillations (LCOs) in the rudder DOF. Response amplitudes and frequencies in the frequency domain, are shown to agree extremely well with results obtained in the time-domain via direct numerical integration of the equations of motion. Both stable and unstable limit-cycle behavior has been predicted, resulting in a detailed set of predictions for the response of the system below the flutter boundary.

  5. SRB/SLEEC (Solid Rocket Booster/Shingle Lap Extendible Exit Cone) feasibility study, volume 2. Appendix A: Design study for a SLEEC actuation system (United States)

    Thompson, D. S.


    The results are presented of a design feasibility study of a self-contained (powered) actuation system for a Shingle Lap Extendible Exit Cone (SLEEC) for Transportation System (STS). The evolution of the SLEEC actuation system design is reviewed, the final design concept is summarized, and the results of the detailed study of the final concept of the actuation system are treated. A conservative design using proven mechanical components was established as a major program priority. The final mechanical design has a very low development risk since the components, which consist of ballscrews, gearing, flexible shaft drives, and aircraft cables, have extensive aerospace applications and a history of proven reliability. The mathematical model studies have shown that little or no power is required to deploy the SLEEC actuation system because acceleration forces and internal pressure from the rocket plume provide the required energies. A speed control brake is incorporated in the design in order to control the rate of deployment.

  6. Suitability review of FMEA and reliability analysis for digital plant protection system and digital engineered safety features actuation system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I. S.; Kim, T. K.; Kim, M. C.; Kim, B. S.; Hwang, S. W.; Ryu, K. C. [Hanyang Univ., Seoul (Korea, Republic of)


    Of the many items that should be checked out during a review stage of the licensing application for the I and C system of Ulchin 5 and 6 units, this report relates to a suitability review of the reliability analysis of Digital Plant Protection System (DPPS) and Digital Engineered Safety Features Actuation System (DESFAS). In the reliability analysis performed by the system designer, ABB-CE, fault tree analysis was used as the main methods along with Failure Modes and Effect Analysis (FMEA). However, the present regulatory technique dose not allow the system reliability analysis and its results to be appropriately evaluated. Hence, this study was carried out focusing on the following four items ; development of general review items by which to check the validity of a reliability analysis, and the subsequent review of suitability of the reliability analysis for Ulchin 5 and 6 DPPS and DESFAS L development of detailed review items by which to check the validity of an FMEA, and the subsequent review of suitability of the FMEA for Ulchin 5 and 6 DPPS and DESFAS ; development of detailed review items by which to check the validity of a fault tree analysis, and the subsequent review of suitability of the fault tree for Ulchin 5 and 6 DPPS and DESFAS ; an integrated review of the safety and reliability of the Ulchin 5 and 6 DPPS and DESFAS based on the results of the various reviews above and also of a reliability comparison between the digital systems and the comparable analog systems, i.e., and analog Plant Protection System (PPS) and and analog Engineered Safety Features Actuation System (ESFAS). According to the review mentioned above, the reliability analysis of Ulchin 5 and 6 DPPS and DESFAS generally satisfies the review requirements. However, some shortcomings of the analysis were identified in our review such that the assumed test periods for several equipment were not properly incorporated in the analysis, and failures of some equipment were not included in the

  7. Refillable and magnetically actuated drug delivery system using pear-shaped viscoelastic membrane

    KAUST Repository

    So, Hongyun


    We report a refillable and valveless drug delivery device actuated by an external magnetic field for on-demand drug release to treat localized diseases. The device features a pear-shaped viscoelastic magnetic membrane inducing asymmetrical deflection and consecutive touchdown motion to the bottom of the dome-shaped drug reservoir in response to a magnetic field, thus achieving controlled discharge of the drug. Maximum drug release with 18 ± 1.5 μg per actuation was achieved under a 500 mT magnetic flux density, and various controlled drug doses were investigated with the combination of the number of accumulated actuations and the strength of the magnetic field.

  8. Refillable and magnetically actuated drug delivery system using pear-shaped viscoelastic membrane. (United States)

    So, Hongyun; Seo, Young Ho; Pisano, Albert P


    We report a refillable and valveless drug delivery device actuated by an external magnetic field for on-demand drug release to treat localized diseases. The device features a pear-shaped viscoelastic magnetic membrane inducing asymmetrical deflection and consecutive touchdown motion to the bottom of the dome-shaped drug reservoir in response to a magnetic field, thus achieving controlled discharge of the drug. Maximum drug release with 18 ± 1.5 μg per actuation was achieved under a 500 mT magnetic flux density, and various controlled drug doses were investigated with the combination of the number of accumulated actuations and the strength of the magnetic field.

  9. Towards Sensor-Actuator Coupling in an Automated Order Picking System by Detecting Sealed Seams on Pouch Packed Goods

    Directory of Open Access Journals (Sweden)

    Frank Weichert


    Full Text Available In this paper, a novel concept of coupling the actuators of an automated order picking system for pouch packed goods with an embedded CCD camera sensor by means of image processing and machine learning is presented. The picking system mechanically combines the conveyance and singularization of a still-connected chain of pouch packed goods in a single machinery. The proposed algorithms perform a per-frame processing of the captured images in real-time to detect the sealed seams of the ongoing pouches. The detections are used to deduce cutting decisions in order to control the system’s actuators, namely the drive pulley for conveyance and the cutting device for the separation. Within this context, two controlling strategies are presented as well which specify the interaction of the sensor and the actuators. The detection is carried out by two different marker detection strategies: enhanced Template Matching as a heuristic and Support Vector Machines as a supervised classification based concept. Depending on the employed marker, detection rates of almost 100% with a calculation time of less than 40 ms are possible. From a logistic point of view, sealed seam widths of 20 mm prove feasible.

  10. Worcester 1 Inch Solenoid Actuated Gas Operated VPS System Ball Valve

    Energy Technology Data Exchange (ETDEWEB)



    1 inch Gas-operated full-port ball valve incorporates a solenoid and limit switches as integral parts of the actuator. The valve is normally open and fails safe to the closed position. The associated valve position switch is class GS.

  11. More Electric Landing Gear Actuation Study


    Li, Wei


    This report addresses the problem of landing gear actuation system design on more-electric aircraft (MEA). Firstly, information about more-electric aircraft and more-electric actuators was gathered and sorted. Current more-electric landing actuation system applications and researches were also summarized. Then several possible more-electric landing gear actuation concepts were identified. To evaluate these concepts, the case study method has been used. A concept aircraft “MR...

  12. Hydraulically actuated artificial muscles (United States)

    Meller, M. A.; Tiwari, R.; Wajcs, K. B.; Moses, C.; Reveles, I.; Garcia, E.


    Hydraulic Artificial Muscles (HAMs) consisting of a polymer tube constrained by a nylon mesh are presented in this paper. Despite the actuation mechanism being similar to its popular counterpart, which are pneumatically actuated (PAM), HAMs have not been studied in depth. HAMs offer the advantage of compliance, large force to weight ratio, low maintenance, and low cost over traditional hydraulic cylinders. Muscle characterization for isometric and isobaric tests are discussed and compared to PAMs. A model incorporating the effect of mesh angle and friction have also been developed. In addition, differential swelling of the muscle on actuation has also been included in the model. An application of lab fabricated HAMs for a meso-scale robotic system is also presented.

  13. Design of a piezoelectric rotation actuator

    NARCIS (Netherlands)

    Holterman, J.; de Vries, Theodorus J.A.; Babakhani, B.; Brouwer, Dannis Michel


    In order to facilitate active damping within a linear motion system, a self-sensing piezoelectric rotation actuator has been designed. The rotation actuator consists of two piezoelectric stacks that function as linear actuators, embedded in a mechanical interface with several elastic elements, thus

  14. Space Shuttle Main Engine control system. [hydraulic actuator with digital control (United States)

    Seitz, P. F.; Searle, R. F.


    The Space Shuttle Main Engine is a reusable, high-performance rocket engine being developed by the Rocketdyne Div. of Rockwell International to satisfy the operational requirements of the Space Shuttle Orbiter Vehicle. The design incorporates a hydraulically actuated, closed-loop servosystem controlled and monitored by a programmable electronic digital controller. The controller accepts vehicle commands for the various engine operational phases, positions the appropriate valves, monitors the engine for the required performance precisions and conditions, and provides redundancy management.

  15. Development of High Temperature Electro-Magnetic Actuators (HTEMA) for Aircraft Propulsion Systems (Preprint) (United States)


    Cu Cycloid    Ball/Roller Thermoelectric Sensorless   Commutation Planetary    Ceramic/Metal Insulation  Encoder   Harmonic Hybrid Radiation  Shield...Electro Motive Force ( EMF ) voltage when unpowered, which may be advantageous in some failure modes. An ONR Phase I study on a linear back emf generated when unpowered. This may be an advantage in failure modes and effects analyses (FMEA). Given the motor is used in an aircraft

  16. Flight Verification of Direct Digital Drive for an Advanced Flight Control Actuation System (AFCAS) in the T-2C Aircraft. (United States)


    clock oscillator, power on reset timer, and memory decoding logic. - 1024 Bytes of RAM. - Sockets for up to 4096 bytes of Alterable Read Only Memory ( AROM ...REQUIREMENTS +5 VDC AT 1.1A (MAX) WITHOUT AROMs /ROMs +12 VDC AT 20mA (MAX) -12 VDC AT 25mA (MAX) WIIH FOUR AROMs /ROMs +5 VDC AT 1.3A (MAX) +12 VDC AT...Control Actuation System I Amp Ampere ’ AROM Alterable Read Only Memory 3 Aux Auxiliary I OC Degrees Celsius cc/min cubic centimeters per minute I c

  17. Study of the Control System With the Smith Predictor and Autotuning Algorithm AT-2 for Thermal Control Objects With the Constant Speed Actuator

    Directory of Open Access Journals (Sweden)

    Kuzishchin Viktor F.


    Full Text Available The application of the Smith predictor in the control system with a constant speed actuator is considered. In order to make it possible to use the Smith predictor a PID-controller with autotuning is used, the autotuning provides the control object model using a self-oscillation mode. The control object has a second order transfer function with a transport delay. The performance of the system was analyzed on an experimental workbench with the industrial constant speed actuator and a physical model of the control object. Recommendations are given, how to correct the PID-law parameters in order to improve the system performance.

  18. Integrated lab-on-chip biosensing systems based on magnetic particle actuation--a comprehensive review. (United States)

    van Reenen, Alexander; de Jong, Arthur M; den Toonder, Jaap M J; Prins, Menno W J


    The demand for easy to use and cost effective medical technologies inspires scientists to develop innovative lab-on-chip technologies for point-of-care in vitro diagnostic testing. To fulfill medical needs, the tests should be rapid, sensitive, quantitative, and miniaturizable, and need to integrate all steps from sample-in to result-out. Here, we review the use of magnetic particles actuated by magnetic fields to perform the different process steps that are required for integrated lab-on-chip diagnostic assays. We discuss the use of magnetic particles to mix fluids, to capture specific analytes, to concentrate analytes, to transfer analytes from one solution to another, to label analytes, to perform stringency and washing steps, and to probe biophysical properties of the analytes, distinguishing methodologies with fluid flow and without fluid flow (stationary microfluidics). Our review focuses on efforts to combine and integrate different magnetically actuated assay steps, with the vision that it will become possible in the future to realize integrated lab-on-chip biosensing assays in which all assay process steps are controlled and optimized by magnetic forces.

  19. Rate dependent direct inverse hysteresis compensation of piezoelectric micro-actuator used in dual-stage hard disk drive head positioning system (United States)

    Rahman, Md. Arifur; Al Mamun, Abdullah; Yao, Kui


    The head positioning servo system in hard disk drive is implemented nowadays using a dual-stage actuator—the primary stage consisting of a voice coil motor actuator providing long range motion and the secondary stage controlling the position of the read/write head with fine resolution. Piezoelectric micro-actuator made of lead zirconate titanate (PZT) has been a popular choice for the secondary stage. However, PZT micro-actuator exhibits hysteresis—an inherent nonlinear characteristic of piezoelectric material. The advantage expected from using the secondary micro-actuator is somewhat lost by the hysteresis of the micro-actuator that contributes to tracking error. Hysteresis nonlinearity adversely affects the performance and, if not compensated, may cause inaccuracy and oscillation in the response. Compensation of hysteresis is therefore an important aspect for designing head-positioning servo system. This paper presents a new rate dependent model of hysteresis along with rigorous analysis and identification of the model. Parameters of the model are found using particle swarm optimization. Direct inverse of the proposed rate-dependent generalized Prandtl-Ishlinskii model is used as the hysteresis compensator. Effectiveness of the overall solution is underscored through experimental results.

  20. Gear-Driven Turnbuckle Actuator (United States)

    Rivera, Ricky N.


    This actuator design allows the extension and contraction of turnbuckle assemblies. It can be operated manually or remotely, and is extremely compact. It is ideal for turnbuckles that are hard to reach by conventional tools. The tool assembly design solves the problem of making accurate adjustments to the variable geometry guide vanes without having to remove and reinstall the actuator system back on the engine. The actuator does this easily by adjusting the length of the turnbuckles while they are still attached to the engine.

  1. T-Slide Linear Actuators (United States)

    Vranish, John


    T-slide linear actuators use gear bearing differential epicyclical transmissions (GBDETs) to directly drive a linear rack, which, in turn, performs the actuation. Conventional systems use a rotary power source in conjunction with a nut and screw to provide linear motion. Non-back-drive properties of GBDETs make the new actuator more direct and simpler. Versions of this approach will serve as a long-stroke, ultra-precision, position actuator for NASA science instruments, and as a rugged, linear actuator for NASA deployment duties. The T slide can operate effectively in the presence of side forces and torques. Versions of the actuator can perform ultra-precision positioning. A basic T-slide actuator is a long-stroke, rack-and-pinion linear actuator that, typically, consists of a T-slide, several idlers, a transmission to drive the slide (powered by an electric motor) and a housing that holds the entire assembly. The actuator is driven by gear action on its top surface, and is guided and constrained by gear-bearing idlers on its other two parallel surfaces. The geometry, implemented with gear-bearing technology, is particularly effective. An electronic motor operating through a GBDET can directly drive the T slide against large loads, as a rack and pinion linear actuator, with no break and no danger of back driving. The actuator drives the slide into position and stops. The slide holes position with power off and no brake, regardless of load. With the T slide configuration, this GBDET has an entire T-gear surface on which to operate. The GB idlers coupling the other two T slide parallel surfaces to their housing counterpart surfaces provide constraints in five degrees-of-freedom and rolling friction in the direction of actuation. Multiple GB idlers provide roller bearing strength sufficient to support efficient, rolling friction movement, even in the presence of large, resisting forces. T-slide actuators can be controlled using the combination of an off

  2. Digital Position Control System of a Motorized Valve in a Process Plant Using Hybrid Stepper Motor as Actuator

    Directory of Open Access Journals (Sweden)



    Full Text Available In any control loop of a process plant, the motorized valve, used as a final control element, may be required to be positioned according to the set point decided by the process requirement. There are various types of position control techniques of a motorized valve. The position control systems used in different applications need to meet the high performance, accuracy and reliability to achieve the desired output. Microcontrollers can be used as suitable means for meeting these needs. In the present paper, a position control scheme of a motorized valve has been described using microcontroller-based configuration for controlling stepper motor as actuator. The final calibration data reported in the paper reveal the linearity and reliability of the control system.

  3. Structural Sizing Methodology for the Tendon-Actuated Lightweight In-Space MANipulator (TALISMAN) System (United States)

    Jones, Thomas C.; Dorsey, John T.; Doggett, William R.


    The Tendon-Actuated Lightweight In-Space MANipulator (TALISMAN) is a versatile long-reach robotic manipulator that is currently being tested at NASA Langley Research Center. TALISMAN is designed to be highly mass-efficient and multi-mission capable, with applications including asteroid retrieval and manipulation, in-space servicing, and astronaut and payload positioning. The manipulator uses a modular, periodic, tension-compression design that lends itself well to analytical modeling. Given the versatility of application for TALISMAN, a structural sizing methodology was developed that could rapidly assess mass and configuration sensitivities for any specified operating work space, applied loads and mission requirements. This methodology allows the systematic sizing of the key structural members of TALISMAN, which include the truss arm links, the spreaders and the tension elements. This paper summarizes the detailed analytical derivations and methodology that support the structural sizing approach and provides results from some recent TALISMAN designs developed for current and proposed mission architectures.

  4. Meso scale flextensional piezoelectric actuators (United States)

    York, Peter A.; Jafferis, Noah T.; Wood, Robert J.


    We present an ultra-thin meso scale piezoelectric actuator consisting of a piezoceramic beam and a carbon fiber displacement-amplification frame. We show that the actuator can be designed to achieve a wide range of force/displacement characteristics on the mN/μm scales. The best performing design achieved a free displacement of 106 μm and a blocked force of 73 mN, yielding a total energy density of 0.51 {{Jkg}}-1 for the 7.6 mg system. We describe a printed circuit MEMS process for fabricating the actuator that incorporates laser micromachining, chemical vapor deposition, and precision carbon fiber lamination. Lastly, we report the incorporation of the actuator into a microgripper and describe other promising application opportunities in micro-optics and micro-laser systems.

  5. Lifetime of dielectric elastomer stack actuators (United States)

    Lotz, Peter; Matysek, Marc; Schlaak, Helmut F.


    Dielectric elastomer stack actuators (DESA) are well suited for the use in mobile devices, fluidic applications and small electromechanical systems. Despite many improvements during the last years the long term behavior of dielectric elastomer actuators in general is not known or has not been published. The first goal of the study is to characterize the overall lifetime under laboratory conditions and to identify potential factors influencing lifetime. For this we have designed a test setup to examine 16 actuators at once. The actuators are subdivided into 4 groups each with a separate power supply and driving signal. To monitor the performance of the actuators driving voltage and current are measured continuously and additionally, the amplitude of the deformations of each actuator is measured sequentially. From our first results we conclude that lifetime of these actuators is mainly influenced by the contact material between feeding line and multilayer electrodes. So far, actuators themselves are not affected by long term actuation. With the best contact material actuators can be driven for more than 2700 h at 200 Hz with an electrical field strength of 20 V/μm. This results in more than 3 billion cycles. Actually, there are further actuators driven at 10 Hz for more than 4000 hours and still working.

  6. Development of a Micro-Step Voltage-Fed Actuator with a Novel Stepper Motor for Automobile AGS Systems (United States)

    Rhyu, Se-Hyun; Lee, Jeong-Jong; Gu, Bon-Gwan; Choi, Byung-Dae; Lim, Jung-Hyuk


    This paper presents an improved micro-step voltage-fed actuator for an automobile active grill shutter (AGS) system. A novel structured stepper motor, which contains both the main and auxiliary teeth in the stator, is proposed for the actuator. In a normal permanent magnet (PM) motor coils are generally wound on all the stator teeth, however, in the proposed motor, the winding is only on the main teeth. Because of the absence of coils in the auxiliary teeth, the proposed stepper motor possesses the following advantages: simple structure, lighter weight, smaller volume, and less time consumption. The unique auxiliary poles in the stepper motor supply the flux path to increase the step resolution even without any coils. The characteristics of the proposed stepper motor were investigated using finite element analysis. In particular, the effect of the magnetization distribution of the PM on the motor performance was investigated during the analysis. Cogging torque, which causes noise and vibration issues, was minimized by the tooth-shape optimization. In addition, a micro-step voltage-fed algorithm was implemented for a high-resolution position control. By employing a current close to a sine wave using space vector pulse-width modulation, a high-quality current waveform with a high resolution was obtained. Finally, the proposed prototype was fabricated, and the cogging torque, back-electromotive force, and current characteristics were measured by mounting the prototype on the AGS system. Both the analysis and experimental results validate the performance improvement from the proposed motor and its possible application for the flap control of the AGS system. PMID:24803193

  7. Development of a Micro-Step Voltage-Fed Actuator with a Novel Stepper Motor for Automobile AGS Systems

    Directory of Open Access Journals (Sweden)

    Se-Hyun Rhyu


    Full Text Available This paper presents an improved micro-step voltage-fed actuator for an automobile active grill shutter (AGS system. A novel structured stepper motor, which contains both the main and auxiliary teeth in the stator, is proposed for the actuator. In a normal permanent magnet (PM motor coils are generally wound on all the stator teeth, however, in the proposed motor, the winding is only on the main teeth. Because of the absence of coils in the auxiliary teeth, the proposed stepper motor possesses the following advantages: simple structure, lighter weight, smaller volume, and less time consumption. The unique auxiliary poles in the stepper motor supply the flux path to increase the step resolution even without any coils. The characteristics of the proposed stepper motor were investigated using finite element analysis. In particular, the effect of the magnetization distribution of the PM on the motor performance was investigated during the analysis. Cogging torque, which causes noise and vibration issues, was minimized by the tooth-shape optimization. In addition, a micro-step voltage-fed algorithm was implemented for a high-resolution position control. By employing a current close to a sine wave using space vector pulse-width modulation, a high-quality current waveform with a high resolution was obtained. Finally, the proposed prototype was fabricated, and the cogging torque, back-electromotive force, and current characteristics were measured by mounting the prototype on the AGS system. Both the analysis and experimental results validate the performance improvement from the proposed motor and its possible application for the flap control of the AGS system.

  8. Development of a micro-step voltage-fed actuator with a novel stepper motor for automobile AGS systems. (United States)

    Rhyu, Se-Hyun; Lee, Jeong-Jong; Gu, Bon-Gwan; Choi, Byung-Dae; Lim, Jung-Hyuk


    This paper presents an improved micro-step voltage-fed actuator for an automobile active grill shutter (AGS) system. A novel structured stepper motor, which contains both the main and auxiliary teeth in the stator, is proposed for the actuator. In a normal permanent magnet (PM) motor coils are generally wound on all the stator teeth, however, in the proposed motor, the winding is only on the main teeth. Because of the absence of coils in the auxiliary teeth, the proposed stepper motor possesses the following advantages: simple structure, lighter weight, smaller volume, and less time consumption. The unique auxiliary poles in the stepper motor supply the flux path to increase the step resolution even without any coils. The characteristics of the proposed stepper motor were investigated using finite element analysis. In particular, the effect of the magnetization distribution of the PM on the motor performance was investigated during the analysis. Cogging torque, which causes noise and vibration issues, was minimized by the tooth-shape optimization. In addition, a micro-step voltage-fed algorithm was implemented for a high-resolution position control. By employing a current close to a sine wave using space vector pulse-width modulation, a high-quality current waveform with a high resolution was obtained. Finally, the proposed prototype was fabricated, and the cogging torque, back-electromotive force, and current characteristics were measured by mounting the prototype on the AGS system. Both the analysis and experimental results validate the performance improvement from the proposed motor and its possible application for the flap control of the AGS system.

  9. A microfluidic control system with re-usable micropump/valve actuator and injection moulded disposable polymer lab-on-a-slide

    DEFF Research Database (Denmark)

    Bu, Minqiang; Perch-Nielsen, Ivan R.; Yi, Sun


    A microfluidic control system consisting of micropump/valves with a re-usable pneumatic actuator and a disposable polymer lab-on-a-slide is presented. The lab-on-a-slide was fabricated using low cost methods, such as injection moulding of TOPAS® cyclic olefin copolymer (COC) slide, lamination...... of different layers of polymer, and ultrasonic welding of TOPAS® lid to the slide. The re-usable pneumatic actuator not only simplifies the design of the lab-on-a-slide and reduces the fabrication cost, but also reduces the possibility of cross contamination during replacement of the disposable lab...

  10. Development of a 3D Parallel Mechanism Robot Arm with Three Vertical-Axial Pneumatic Actuators Combined with a Stereo Vision System

    Directory of Open Access Journals (Sweden)

    Hao-Ting Lin


    Full Text Available This study aimed to develop a novel 3D parallel mechanism robot driven by three vertical-axial pneumatic actuators with a stereo vision system for path tracking control. The mechanical system and the control system are the primary novel parts for developing a 3D parallel mechanism robot. In the mechanical system, a 3D parallel mechanism robot contains three serial chains, a fixed base, a movable platform and a pneumatic servo system. The parallel mechanism are designed and analyzed first for realizing a 3D motion in the X-Y-Z coordinate system of the robot’s end-effector. The inverse kinematics and the forward kinematics of the parallel mechanism robot are investigated by using the Denavit-Hartenberg notation (D-H notation coordinate system. The pneumatic actuators in the three vertical motion axes are modeled. In the control system, the Fourier series-based adaptive sliding-mode controller with H∞ tracking performance is used to design the path tracking controllers of the three vertical servo pneumatic actuators for realizing 3D path tracking control of the end-effector. Three optical linear scales are used to measure the position of the three pneumatic actuators. The 3D position of the end-effector is then calculated from the measuring position of the three pneumatic actuators by means of the kinematics. However, the calculated 3D position of the end-effector cannot consider the manufacturing and assembly tolerance of the joints and the parallel mechanism so that errors between the actual position and the calculated 3D position of the end-effector exist. In order to improve this situation, sensor collaboration is developed in this paper. A stereo vision system is used to collaborate with the three position sensors of the pneumatic actuators. The stereo vision system combining two CCD serves to measure the actual 3D position of the end-effector and calibrate the error between the actual and the calculated 3D position of the end

  11. Development of a 3D parallel mechanism robot arm with three vertical-axial pneumatic actuators combined with a stereo vision system. (United States)

    Chiang, Mao-Hsiung; Lin, Hao-Ting


    This study aimed to develop a novel 3D parallel mechanism robot driven by three vertical-axial pneumatic actuators with a stereo vision system for path tracking control. The mechanical system and the control system are the primary novel parts for developing a 3D parallel mechanism robot. In the mechanical system, a 3D parallel mechanism robot contains three serial chains, a fixed base, a movable platform and a pneumatic servo system. The parallel mechanism are designed and analyzed first for realizing a 3D motion in the X-Y-Z coordinate system of the robot's end-effector. The inverse kinematics and the forward kinematics of the parallel mechanism robot are investigated by using the Denavit-Hartenberg notation (D-H notation) coordinate system. The pneumatic actuators in the three vertical motion axes are modeled. In the control system, the Fourier series-based adaptive sliding-mode controller with H(∞) tracking performance is used to design the path tracking controllers of the three vertical servo pneumatic actuators for realizing 3D path tracking control of the end-effector. Three optical linear scales are used to measure the position of the three pneumatic actuators. The 3D position of the end-effector is then calculated from the measuring position of the three pneumatic actuators by means of the kinematics. However, the calculated 3D position of the end-effector cannot consider the manufacturing and assembly tolerance of the joints and the parallel mechanism so that errors between the actual position and the calculated 3D position of the end-effector exist. In order to improve this situation, sensor collaboration is developed in this paper. A stereo vision system is used to collaborate with the three position sensors of the pneumatic actuators. The stereo vision system combining two CCD serves to measure the actual 3D position of the end-effector and calibrate the error between the actual and the calculated 3D position of the end-effector. Furthermore, to

  12. Apu/hydraulic/actuator Subsystem Computer Simulation. Space Shuttle Engineering and Operation Support, Engineering Systems Analysis. [for the space shuttle (United States)


    Major developments are examined which have taken place to date in the analysis of the power and energy demands on the APU/Hydraulic/Actuator Subsystem for space shuttle during the entry-to-touchdown (not including rollout) flight regime. These developments are given in the form of two subroutines which were written for use with the Space Shuttle Functional Simulator. The first subroutine calculates the power and energy demand on each of the three hydraulic systems due to control surface (inboard/outboard elevons, rudder, speedbrake, and body flap) activity. The second subroutine incorporates the R. I. priority rate limiting logic which limits control surface deflection rates as a function of the number of failed hydraulic. Typical results of this analysis are included, and listings of the subroutines are presented in appendicies.

  13. Control of Adjustable Compliant Actuators

    Directory of Open Access Journals (Sweden)

    Berno J.E. Misgeld


    Full Text Available Adjustable compliance or variable stiffness actuators comprise an additional element to elastically decouple the actuator from the load and are increasingly applied to human-centered robotic systems. The advantages of such actuators are of paramount importance in rehabilitation robotics, where requirements demand safe interaction between the therapy system and the patient. Compliant actuator systems enable the minimization of large contact forces arising, for example, from muscular spasticity and have the ability to periodically store and release energy in cyclic movements. In order to overcome the loss of bandwidth introduced by the elastic element and to guarantee a higher range in force/torque generation, new actuator designs consider variable or nonlinear stiffness elements, respectively. These components cannot only be adapted to the walking speed or the patient condition, but also entail additional challenges for feedback control. This paper introduces a novel design method for an impedance-based controller that fulfills the control objectives and compares the performance and robustness to a classical cascaded control approach. The new procedure is developed using a non-standard positive-real Η2 controller design and is applied to a loop-shaping approach. Robust norm optimal controllers are designed with regard to the passivity of the actuator load-impedance transfer function and the servo control problem. Classical cascaded and positive-real Η2 controller designs are validated and compared in simulations and in a test bench using a passive elastic element of varying stiffness.

  14. A micro-optical system for endoscopy based on mechanical compensation paradigm using miniature piezo-actuation. (United States)

    Cerveri, Pietro; Zazzarini, Cynthia Corinna; Patete, Paolo; Baroni, Guido


    The goal of the study was to investigate the feasibility of a novel miniaturized optical system for endoscopy. Fostering the mechanical compensation paradigm, the modeled optical system, composed by 14 lenses, separated in 4 different sets, had a total length of 15.55mm, an effective focal length ranging from 1.5 to 4.5mm with a zoom factor of about 2.8×, and an angular field of view up to 56°. Predicted maximum lens travel was less than 3.5mm. The consistency of the image plane height across the magnification range testified the zoom capability. The maximum predicted achromatic astigmatism, transverse spherical aberration, longitudinal spherical aberration and relative distortion were less than or equal to 25μm, 15μm, 35μm and 12%, respectively. Tests on tolerances showed that the manufacturing and opto-mechanics mounting are critical as little deviations from design dramatically decrease the optical performances. However, recent micro-fabrication technology can guarantee tolerances close to nominal design. A closed-loop actuation unit, devoted to move the zoom and the focus lens sets, was implemented adopting miniaturized squiggle piezo-motors and magnetic position encoders based on Hall effect. Performance results, using a prototypical test board, showed a positioning accuracy of less than 5μm along a lens travel path of 4.0mm, which was in agreement with the lens set motion features predicted by the analysis. In conclusion, this study demonstrated the feasibility of the optical design and the viability of the actuation approach while tolerances must be carefully taken into account. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

  15. A recurrent neural-network-based sensor and actuator fault detection and isolation for nonlinear systems with application to the satellite's attitude control subsystem. (United States)

    Talebi, H A; Khorasani, K; Tafazoli, S


    This paper presents a robust fault detection and isolation (FDI) scheme for a general class of nonlinear systems using a neural-network-based observer strategy. Both actuator and sensor faults are considered. The nonlinear system considered is subject to both state and sensor uncertainties and disturbances. Two recurrent neural networks are employed to identify general unknown actuator and sensor faults, respectively. The neural network weights are updated according to a modified backpropagation scheme. Unlike many previous methods developed in the literature, our proposed FDI scheme does not rely on availability of full state measurements. The stability of the overall FDI scheme in presence of unknown sensor and actuator faults as well as plant and sensor noise and uncertainties is shown by using the Lyapunov's direct method. The stability analysis developed requires no restrictive assumptions on the system and/or the FDI algorithm. Magnetorquer-type actuators and magnetometer-type sensors that are commonly employed in the attitude control subsystem (ACS) of low-Earth orbit (LEO) satellites for attitude determination and control are considered in our case studies. The effectiveness and capabilities of our proposed fault diagnosis strategy are demonstrated and validated through extensive simulation studies.

  16. A Multilayer Feed Forward Small-World Neural Network Controller and Its Application on Electrohydraulic Actuation System

    Directory of Open Access Journals (Sweden)

    Xiaohu Li


    Full Text Available Being difficult to attain the precise mathematical models, traditional control methods such as proportional integral (PI and proportional integral differentiation (PID cannot meet the demands for real time and robustness when applied in some nonlinear systems. The neural network controller is a good replacement to overcome these shortcomings. However, the performance of neural network controller is directly determined by neural network model. In this paper, a new neural network model is constructed with a structure topology between the regular and random connection modes based on complex network, which simulates the brain neural network as far as possible, to design a better neural network controller. Then, a new controller is designed under small-world neural network model and is investigated in both linear and nonlinear systems control. The simulation results show that the new controller basing on small-world network model can improve the control precision by 30% in the case of system with random disturbance. Besides the good performance of the new controller in tracking square wave signals, which is demonstrated by the experiment results of direct drive electro-hydraulic actuation position control system, it works well on anti-interference performance.

  17. Advanced Electroactive Single Crystal and Polymer Actuator Concepts for Passive Optics Project (United States)

    National Aeronautics and Space Administration — TRS Technologies proposes large stroke and high precision piezoelectric single crystal and electroactive polymer actuator concepts?HYBrid Actuation System (HYBAS)...

  18. Fault Detection for Diesel Engine Actuator

    DEFF Research Database (Denmark)

    Blanke, M.; Bøgh, S.A.; Jørgensen, R.B.


    Feedback control systems are vulnerable to faults in control loop sensors and actuators, because feedback actions may cause abrupt responses and process damage when faults occur.......Feedback control systems are vulnerable to faults in control loop sensors and actuators, because feedback actions may cause abrupt responses and process damage when faults occur....

  19. Control System Design Implementation and Preliminary Demonstration for a Tendon-Actuated Lightweight In-Space MANipulator (TALISMAN) (United States)

    Komendera, Erik E.; Doggett, William R.; Dorsey, John T.; Debus, Thomas J.; Holub, Kris; Dougherty, Sean P.


    Satellite servicing is a high priority task for NASA and the space industry, addressing the needs of a variety of missions, and potentially lowering the overall cost of missions through refurbishment and reuse. However, the ability to service satellites is severely limited by the lack of long reach manipulation capability and inability to launch new devices due the end of the Space Transport System, or Space Shuttle Program. This paper describes the design and implementation of a control system for a Tendon-Actuated Lightweight In-Space MANipulator (TALISMAN), including; defining the forward and inverse kinematics, endpoint velocity to motor velocity, required cable tensions, and a proportional-integral-derivative (PID) controller. The tensions and velocities necessary to maneuver and capture small and large payloads are also discussed. To demonstrate the utility of the TALISMAN for satellite servicing, this paper also describes a satellite servicing demonstration using two TALISMAN prototypes to grasp and inspect a satellite mockup. Potential avenues for improving the control system are discussed.

  20. Integrated Health Monitoring and Fast on-Line Actuator Reconfiguration Enhancement (IHM-FLARE) System for Air Vehicles Project (United States)

    National Aeronautics and Space Administration — SSCI proposes to develop innovative algorithms for the integration of Health Monitoring (HM) subsystem with the existing FLARE (Fast on-Line Actuator Reconfiguration...

  1. Digital Position Control System of a Motorized Valve in a Process Plant Using Hybrid Stepper Motor as Actuator

    National Research Council Canada - National Science Library

    Subrata Chattopadhyay; Utpal Chakraborty; Arindam Bhakta; Sagarika Pal


    .... Microcontrollers can be used as suitable means for meeting these needs. In the present paper, a position control scheme of a motorized valve has been described using microcontroller-based configuration for controlling stepper motor as actuator...

  2. Study on the graphene-based actuator (United States)

    Xu, Liang; Oh, Il Kwon


    Bilayer actuators comprising of MWCNT (Multi-walled carbon nanotubes) and Graphene oxide (GO) were studied for their actuation performance by using induction heating system. A simple fabrication method namely, filtration of the colloidal suspensions of MWCNT and GO through an Anodisc membrane was used to fabricate the actuators. In case of bilayer actuators, sequential filtration of MWCNTs and Graphene oxide dispersions through a membrane filter membrane was used. Morphological studies by SEM showed that the bilayer paper did not delaminate at the macro-scale and a certain degree of adhesion between MWCNT and GO can be achieved even without any functionalization of either of the constituents of bilayer actuators. Actuation was tested by using the induction heating system, operated at different current densities. Substantial degree of deformation, as much as 0.128 mm-1 at 300 A was measured. The degree of actuation was defined in terms of bending curvature, because the deformation was too large to be detected by conventional displacement laser sensors. An attempt has been made to explain the basic mechanism of bilayer actuator in terms of the differential thermal expansion rates and eddy current which was confirmed from images obtained from thermal camera wherein the variation in bilayer actuator's surface temperature were monitored. Finally the deformation trend under different pulses is also examined.

  3. An Intelligent Sensor Array Distributed System for Vibration Analysis and Acoustic Noise Characterization of a Linear Switched Reluctance Actuator

    Directory of Open Access Journals (Sweden)

    Maria Calado


    Full Text Available This paper proposes a distributed system for analysis and monitoring (DSAM of vibrations and acoustic noise, which consists of an array of intelligent modules, sensor modules, communication bus and a host PC acting as data center. The main advantages of the DSAM are its modularity, scalability, and flexibility for use of different type of sensors/transducers, with analog or digital outputs, and for signals of different nature. Its final cost is also significantly lower than other available commercial solutions. The system is reconfigurable, can operate either with synchronous or asynchronous modes, with programmable sampling frequencies, 8-bit or 12-bit resolution and a memory buffer of 15 kbyte. It allows real-time data-acquisition for signals of different nature, in applications that require a large number of sensors, thus it is suited for monitoring of vibrations in Linear Switched Reluctance Actuators (LSRAs. The acquired data allows the full characterization of the LSRA in terms of its response to vibrations of structural origins, and the vibrations and acoustic noise emitted under normal operation. The DSAM can also be used for electrical machine condition monitoring, machine fault diagnosis, structural characterization and monitoring, among other applications.

  4. An intelligent sensor array distributed system for vibration analysis and acoustic noise characterization of a linear switched reluctance actuator. (United States)

    Salvado, José; Espírito-Santo, António; Calado, Maria


    This paper proposes a distributed system for analysis and monitoring (DSAM) of vibrations and acoustic noise, which consists of an array of intelligent modules, sensor modules, communication bus and a host PC acting as data center. The main advantages of the DSAM are its modularity, scalability, and flexibility for use of different type of sensors/transducers, with analog or digital outputs, and for signals of different nature. Its final cost is also significantly lower than other available commercial solutions. The system is reconfigurable, can operate either with synchronous or asynchronous modes, with programmable sampling frequencies, 8-bit or 12-bit resolution and a memory buffer of 15 kbyte. It allows real-time data-acquisition for signals of different nature, in applications that require a large number of sensors, thus it is suited for monitoring of vibrations in Linear Switched Reluctance Actuators (LSRAs). The acquired data allows the full characterization of the LSRA in terms of its response to vibrations of structural origins, and the vibrations and acoustic noise emitted under normal operation. The DSAM can also be used for electrical machine condition monitoring, machine fault diagnosis, structural characterization and monitoring, among other applications.

  5. The Piezo Actuator-Driven Pulsed Water Jet System for Minimizing Renal Damage after Off-Clamp Laparoscopic Partial Nephrectomy. (United States)

    Kamiyama, Yoshihiro; Yamashita, Shinichi; Nakagawa, Atsuhiro; Fujii, Shinji; Mitsuzuka, Koji; Kaiho, Yasuhiro; Ito, Akihiro; Abe, Takaaki; Tominaga, Teiji; Arai, Yoichi


    In the setting of partial nephrectomy (PN) for renal cell carcinoma, postoperative renal dysfunction might be caused by surgical procedure. The aim of this study was to clarify the technical safety and renal damage after off-clamp laparoscopic PN (LPN) with a piezo actuator-driven pulsed water jet (ADPJ) system. Eight swine underwent off-clamp LPN with this surgical device, while off-clamp open PN was also performed with radio knife or soft coagulation. The length of the removed kidney was 40 mm, and the renal parenchyma was dissected until the renal calyx became clearly visible. The degree of renal degeneration from the resection surface was compared by Hematoxylin-Eosin staining and immunostaining for 1-methyladenosine, a sensitive marker for the ischemic tissue damage. The mRNA levels of neutrophil gelatinase-associated lipocalin (Ngal), a biomarker for acute kidney injury, were measured by quantitative real-time PCR. Off-clamp LPN with ADPJ system was successfully performed while preserving fine blood vessels and the renal calix with little bleeding. In contrast to other devices, the resection surface obtained with the ADPJ system showed only marginal degree of ischemic changes. Indeed, the expression level of Ngal mRNA was lower in the resection surface obtained with the ADPJ system than that with soft coagulation (p = 0.02). Furthermore, using the excised specimens of renal cell carcinoma, we measured the breaking strength at each site of the human kidney, suggesting the applicability of this ADPJ to clinical trials. In conclusion, off-clamp LPN with the ADPJ system could be safely performed with attenuated renal damage.

  6. Electromagnetic rotational actuation.

    Energy Technology Data Exchange (ETDEWEB)

    Hogan, Alexander Lee


    There are many applications that need a meso-scale rotational actuator. These applications have been left by the wayside because of the lack of actuation at this scale. Sandia National Laboratories has many unique fabrication technologies that could be used to create an electromagnetic actuator at this scale. There are also many designs to be explored. In this internship exploration of the designs and fabrications technologies to find an inexpensive design that can be used for prototyping the electromagnetic rotational actuator.

  7. Extended DNA Tile Actuators

    DEFF Research Database (Denmark)

    Kristiansen, Martin; Kryger, Mille; Zhang, Zhao


    A dynamic linear DNA tile actuator is expanded to three new structures of higher complexity. The original DNA actuator was constructed from a central roller strand which hybridizes with two piston strands by forming two half-crossover junctions. A linear expansion of the actuator is obtained...

  8. Robust fault detection and isolation technique for single-input/single-output closed-loop control systems that exhibit actuator and sensor faults

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Alavi, S. M. Mahdi; Hayes, M. J.


    ) a graphical environment is provided for the design of fault detection (FD) filter, which is intuitively appealing from an engineering perspective. The FD filter can easily be obtained by manually shaping the frequency response into the complex plane. The question of interaction between actuator and sensor......An integrated quantitative feedback design and frequency-based fault detection and isolation (FDI) approach is presented for single-input/single-output systems. A novel design methodology, based on shaping the system frequency response, is proposed to generate an appropriate residual signal...... that is sensitive to actuator and sensor faults in the presence of model uncertainty and exogenous unknown (unmeasured) disturbances. The key features of this technique are: (1) the uncertain phase information is fully addressed by the design equations, resulting in a minimally conservative over-design and (2...

  9. SiC/GaN Based Optically Triggered MESFET for High Power Efficiency and High Radiation Resistance Solid State Switch Application for Actuator System (United States)


    High Radiation Resistance Solid State Switch Application for Actuator System The views, opinions and/or findings contained in this report are those of...Final Report: SiC/GaN Based Optically Triggered MESFET for High Power Efficiency and High Radiation Resistance Solid State Switch Application for...performed by the reactive ion etching (RIE) of silicon carbide in fluorinated -gas (CHF3, CBrF3, CF4, SF6 and NF3) plasma and inductively coupled plasma

  10. Minimally Actuated Serial Robot


    Mann, Moshe P.; Damti, Lior; Zarrouk, David


    In this paper, we propose a novel type of serial robot with minimal actuation. The robot is a serial rigid structure consisting of multiple links connected by passive joints and of movable actuators. The novelty of this robot is that the actuators travel over the links to a given joint and adjust the relative angle between the two adjacent links. The joints passively preserve their angles until one of the actuators moves them again. This actuation can be applied to any serial robot with two o...

  11. Adaptive Fault-Tolerant Tracking Control of Nonaffine Nonlinear Systems with Actuator Failure

    Directory of Open Access Journals (Sweden)

    Hongcheng Zhou


    Full Text Available This paper proposes an adaptive fault-tolerant control scheme for nonaffine nonlinear systems. A model approximation method which is a solution that bridges the gap between affine and nonaffine control systems is developed firstly. A joint estimation approach is based on unscented Kalman filter, in which both failure parameters and states are simultaneously estimated by means of the argument state vector composed of the unknown faults and states. Then, stability analysis is given for the closed-loop system. Finally, the proposed approach is verified using a three-degree-of-freedom simulation of a typical fighter aircraft and the significantly improved system response demonstrates the practical potential of the theoretic results obtained.

  12. On-orbit validation system for space structure composite actuators Project (United States)

    National Aeronautics and Space Administration — This SBIR project delivers an On-orbit Validation System (OVS) that provides performance and durability data for Macro Fiber Composite (MFC) active piezocomposite...

  13. New Sensing Application to Diagnose Power Semiconductor Aging in Actuator Power Drive Systems (United States)

    National Aeronautics and Space Administration — This paper presents a new sensing application to diagnose power semiconductor aging in power drive systems. It has been shown previously that device parasitic...

  14. Advancements in Actuated Musical Instruments

    DEFF Research Database (Denmark)

    Overholt, Daniel; Berdahl, Edgar; Hamilton, Robert


    This article presents recent developments in actuated musical instruments created by the authors, who also describe an ecosystemic model of actuated performance activities that blur traditional boundaries between the physical and virtual elements of musical interfaces. Actuated musical instruments...... are physical instruments that have been endowed with virtual qualities controlled by a computer in real-time but which are nevertheless tangible. These instruments provide intuitive and engaging new forms of interaction. They are different from traditional (acoustic) and fully automated (robotic) instruments...... in that they produce sound via vibrating element(s) that are co-manipulated by humans and electromechanical systems. We examine the possibilities that arise when such instruments are played in different performative environments and music-making scenarios, and we postulate that such designs may give rise to new...

  15. Distributed fault-tolerant time-varying formation control for high-order linear multi-agent systems with actuator failures. (United States)

    Hua, Yongzhao; Dong, Xiwang; Li, Qingdong; Ren, Zhang


    This paper investigates the fault-tolerant time-varying formation control problems for high-order linear multi-agent systems in the presence of actuator failures. Firstly, a fully distributed formation control protocol is presented to compensate for the influences of both bias fault and loss of effectiveness fault. Using the adaptive online updating strategies, no global knowledge about the communication topology is required and the bounds of actuator failures can be unknown. Then an algorithm is proposed to determine the control parameters of the fault-tolerant formation protocol, where the time-varying formation feasible conditions and an approach to expand the feasible formation set are given. Furthermore, the stability of the proposed algorithm is proven based on the Lyapunov-like theory. Finally, two simulation examples are given to demonstrate the effectiveness of the theoretical results. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  16. An H-module linear actuator for medical equipment applications

    DEFF Research Database (Denmark)

    Liu, Xiao; Wu, Keyuan; ye, yunyue


    An H-module linear actuator (HMLA) is proposed in this paper for medical equipment applications. Compared to the existing linear actuators used in medical equipment, the proposed H-module linear actuator has much lower normal force, which makes use of an additional air-suspension system unnecessary...

  17. A new converter for improving efficiency of multi-actuators fluid power system

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Yong; Shang, JianZhong; Yang, JunHong; Wang Zhuo [National University of Defense Technology, Changsha (China)


    This paper is concerned with the application of energy efficient fluid power in mobile robots system and proposes a new fluid power converter system which is analogous to a boost converter in power electronics. The fluid power converter system is based on the principle of pulse-width modulation. The fluid power converter has an effect akin to an electrical switched inductance transformer, wherein the output pressure or flow rate can be stepped up or down. Using an inductive reactance device (an inertia mass-block), the output flow and pressure can be varied to meet the load by a means that does not rely on dissipation of power (the resistance control). The simulation model based on the mathematics models of the components is built to analyse the performance of the fluid power converter. It is clearly shown that the fluid power converter has higher energy efficiency than conventional resistance control manners.

  18. Efficient control of servo pneumatic actuator system utilizing by-pass ...

    Indian Academy of Sciences (India)

    The issue of energy saving nowadays is very crucial. ... The higher the positioning accuracy, the higher the compressed air consumption is. ... that this control algorithm provides a satisfactory positioning accuracy and robustness of the system, simultaneously reducing compressed air consumption by as much as 29.5%.

  19. Mechatronic Design of an Electromagnetically Levitated Linear Positioning System using Novel Multi-DoF Actuators

    NARCIS (Netherlands)

    Laro, D.A.H.


    The development of contactless electromagnetically levitated positioning systems is stimulated by the demand for vacuum compatible production machines. These vacuum compatible machines are used e.g. in the development of faster semiconductor chips and optical discs with larger data capacity. A novel

  20. Design and Comparative Analysis of a Retrofitted Liquid Cooling System for High-Power Actuators

    Directory of Open Access Journals (Sweden)

    Nicholas Paine


    Full Text Available This paper presents an in-depth system-level experimental analysis comparing air-cooled and liquid-cooled commercial off-the-shelf (COTS electric motors. Typically, liquid-cooled electric motors are reserved for large, expensive, high-end applications where the design of the motor’s electromagnetic components are closely coupled to its cooling system. By applying liquid cooling to a pre-existing motor design, this work helps bring the performance advantages of liquid cooling to smaller scale and lower cost applications. Prior work in this area gives little insight to designers of such systems. Conversely, this work aims to improve the understanding of liquid-cooled COTS motors by reporting empirically-observed factors of improvement for motor current, torque, output power and system efficiency. These measurements are obtained using a new liquid-cooled motor housing design that improves the ease of maintenance and component reuse compared to existing work. It is confirmed that datasheet motor thermal properties may serve as a reasonable guide for anticipating continuous torque performance, but may over-specify continuous power output. For the motor used in this test, continuous torque output is increased by a factor of 2.58, matching to within 9% of expected datasheet values. Continuous power output is increased by a factor of two with only 2.2% reduced efficiency compared to air-cooling.

  1. Communication-Link Approach to Actuation of Grade-Crossing Motorist-Warning Systems (United States)


    Previous studies indicate that one promising avenue to grade-crossing motorist-warning systems, offering lower cost and independent of railroad-track circuits, is use of a radio-communication link for signal activation. By this means, the presence of...

  2. Sensor-less force-reflecting macro-micro telemanipulation systems by piezoelectric actuators. (United States)

    Amini, H; Farzaneh, B; Azimifar, F; Sarhan, A A D


    This paper establishes a novel control strategy for a nonlinear bilateral macro-micro teleoperation system with time delay. Besides position and velocity signals, force signals are additionally utilized in the control scheme. This modification significantly improves the poor transparency during contact with the environment. To eliminate external force measurement, a force estimation algorithm is proposed for the master and slave robots. The closed loop stability of the nonlinear micro-micro teleoperation system with the proposed control scheme is investigated employing the Lyapunov theory. Consequently, the experimental results verify the efficiency of the new control scheme in free motion and during collision between the slave robot and the environment of slave robot with environment, and the efficiency of the force estimation algorithm. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  3. Design of Mechanically Actuated Aerodynamic Braking System on a Formula Student Race Car (United States)

    Muralidharan, Vivek; Balakrishnan, Abhijith; Vardhan, Vinit Ketan; Meena, Nikita; Kumar, Y. Suresh


    Every second in a racing competition counts the performance of a team against the other. Many innovative and sophisticated techniques are being employed to overcome loses in time and add to the performance of the vehicle. Especially in a car racing challenge there is more freedom to install these innovative systems to empower the car to maximum efficiency due to availability of more space. At the global spectrum there are few events which encourage such innovations. Formula Student Racing competitions are one of the global events organized by the Society of Automotive Engineers of different countries which gives opportunity to university students to build and race formula style cars. Like any other racing competitions in this high octane event having an inch over their opponents is always an advantage. Not just better acceleration and high velocities but also good deceleration is required to excel in the competition. Aerodynamic braking system is utilizing the aerodynamic drag force to create high deceleration. This mechanism can be installed on any car with spoilers with minimum modification. Being a student event great amount of care needs to be given to the safety concerns of the driver.

  4. Self-Sensing Electromagnets for Robotic Tooling Systems: Combining Sensor and Actuator

    Directory of Open Access Journals (Sweden)

    Tobias Kamf


    Full Text Available A low-cost method, which integrates distance sensing functionality into a switched electromagnet by using a hybrid switching mode and current ripple measurements, is proposed. The electromagnet is controlled by a micro-controller via a MOSFET H bridge, utilizing a comparator-based current control. Additionally, a method for calculating the inductance of the electromagnet and approximating the magnetic contact between the electromagnet and its target is also presented. The resulting tool is attached to an industrial robot, and the system performance using this setup is evaluated. Distance sensing in the range of 0 mm to 5.2 mm is demonstrated. It is also shown that the relation between magnetic contact, coil current and calculated inductance can be reduced to a predictive look-up table, enabling the quality of the magnetic contact to be estimated using minimal computational effort.

  5. An SSVEP-actuated brain computer interface using phase-tagged flickering sequences: a cursor system. (United States)

    Lee, Po-Lei; Sie, Jyun-Jie; Liu, Yu-Ju; Wu, Chi-Hsun; Lee, Ming-Huan; Shu, Chih-Hung; Li, Po-Hung; Sun, Chia-Wei; Shyu, Kuo-Kai


    This study presents a new steady-state visual evoked potential (SSVEP)-based brain computer interface (BCI). SSVEPs, induced by phase-tagged flashes in eight light emitting diodes (LEDs), were used to control four cursor movements (up, right, down, and left) and four button functions (on, off, right-, and left-clicks) on a screen menu. EEG signals were measured by one EEG electrode placed at Oz position, referring to the international EEG 10-20 system. Since SSVEPs are time-locked and phase-locked to the onsets of SSVEP flashes, EEG signals were bandpass-filtered and segmented into epochs, and then averaged across a number of epochs to sharpen the recorded SSVEPs. Phase lags between the measured SSVEPs and a reference SSVEP were measured, and targets were recognized based on these phase lags. The current design used eight LEDs to flicker at 31.25 Hz with 45 degrees phase margin between any two adjacent SSVEP flickers. The SSVEP responses were filtered within 29.25-33.25 Hz and then averaged over 60 epochs. Owing to the utilization of high-frequency flickers, the induced SSVEPs were away from low-frequency noises, 60 Hz electricity noise, and eye movement artifacts. As a consequence, we achieved a simple architecture that did not require eye movement monitoring or other artifact detection and removal. The high-frequency design also achieved a flicker fusion effect for better visualization. Seven subjects were recruited in this study to sequentially input a command sequence, consisting of a sequence of eight cursor functions, repeated three times. The accuracy and information transfer rate (mean +/- SD) over the seven subjects were 93.14 +/- 5.73% and 28.29 +/- 12.19 bits/min, respectively. The proposed system can provide a reliable channel for severely disabled patients to communicate with external environments.

  6. Detonator cable initiation system safety investigation: Consequences of energizing the detonator and actuator cables

    Energy Technology Data Exchange (ETDEWEB)

    Osher, J.; Chau, H.; Von Holle, W.


    This study was performed to explore and assess the worst-case response of a W89-type weapons system, damaged so as to expose detonator and/or detonator safing strong link (DSSL) cables to the most extreme, credible lightning-discharge, environment. The test program used extremely high-current-level, fast-rise-time (1- to 2-{mu}s) discharges to simulate lightning strikes to either the exposed detonator or DSSL cables. Discharges with peak currents above 700 kA were required to explode test sections of detonator cable and launch a flyer fast enough potentially to detonate weapon high explosive (HE). Detonator-safing-strong-link (DSSL) cables were exploded in direct contact with hot LX-17 and Ultrafine TATB (UFTATB). At maximum charging voltage, the discharge system associated with the HE firing chamber exploded the cables at more than 600-kA peak current; however, neither LX-17 nor UFTATB detonated at 250{degree}C. Tests showed that intense surface arc discharges of more than 700 kA/cm in width across the surface of hot UFTATB [generally the more sensitive of the two insensitive high explosives (IHE)] could not initiate this hot IHE. As an extension to this study, we applied the same technique to test sections of the much-narrower but thicker-cover-layer W87 detonator cable. These tests were performed at the same initial stored electrical energy as that used for the W89 study. Because of the narrower cable conductor in the W87 cables, discharges greater than 550-kA peak current were sufficient to explode the cable and launch a fast flyer. In summary, we found that lightning strikes to exposed DSSL cables cannot directly detonate LX-17 or UFTATB even at high temperatures, and they pose no HE safety threat.

  7. Iterative Jacobian-Based Inverse Kinematics and Open-Loop Control of an MRI-Guided Magnetically Actuated Steerable Catheter System. (United States)

    Liu, Taoming; Jackson, Russell; Franson, Dominique; Poirot, Nate Lombard; Criss, Reinhardt Kam; Seiberlich, Nicole; Griswold, Mark A; Çavuşoğlu, M Cenk


    This paper presents an iterative Jacobian-based inverse kinematics method for an MRI-guided magnetically-actuated steerable intravascular catheter system. The catheter is directly actuated by magnetic torques generated on a set of current-carrying micro-coils embedded on the catheter tip, by the magnetic field of the magnetic resonance imaging (MRI) scanner. The Jacobian matrix relating changes of the currents through the coils to changes of the tip position is derived using a three dimensional kinematic model of the catheter deflection. The inverse kinematics is numerically computed by iteratively applying the inverse of the Jacobian matrix. The damped least square method is implemented to avoid numerical instability issues that exist during the computation of the inverse of the Jacobian matrix. The performance of the proposed inverse kinematics approach is validated using a prototype of the robotic catheter by comparing the actual trajectories of the catheter tip obtained via open-loop control with the desired trajectories. The results of reproducibility and accuracy evaluations demonstrate that the proposed Jacobian-based inverse kinematics method can be used to actuate the catheter in open-loop to successfully perform complex ablation trajectories required in atrial fibrillation ablation procedures. This study paves the way for effective and accurate closed-loop control of the robotic catheter with real-time feedback from MRI guidance in subsequent research.

  8. Soft buckling actuators

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Dian; Whitesides, George M.


    A soft actuator is described, including: a rotation center having a center of mass; a plurality of bucklable, elastic structural components each comprising a wall defining an axis along its longest dimension, the wall connected to the rotation center in a way that the axis is offset from the center of mass in a predetermined direction; and a plurality of cells each disposed between two adjacent bucklable, elastic structural components and configured for connection with a fluid inflation or deflation source; wherein upon the deflation of the cell, the bucklable, elastic structural components are configured to buckle in the predetermined direction. A soft actuating device including a plurality of the soft actuators and methods of actuation using the soft actuator or soft actuating device disclosed herein are also described.

  9. Remote switch actuator (United States)

    Haas, Edwin Gerard; Beauman, Ronald; Palo, Jr., Stefan


    The invention provides a device and method for actuating electrical switches remotely. The device is removably attached to the switch and is actuated through the transfer of a user's force. The user is able to remain physically removed from the switch site obviating need for protective equipment. The device and method allow rapid, safe actuation of high-voltage or high-current carrying electrical switches or circuit breakers.

  10. Mechatronics and Bioinspiration in Actuator Design and Control

    Directory of Open Access Journals (Sweden)

    J. L. Pons


    Full Text Available Actuators are components of motion control systems in which mechatronics plays a crucial role. They can be regarded as a paradigmatic case in which this mechatronic approach is required. Furthermore, actuator technologies can get new sources of inspiration from nature (bioinspiration. Biological systems are the result of an evolutionary process and show excellent levels of performance. In this paper, we analyse the actuator as a bioinspired mechatronic system through analogies between mechatronics and biological actuating mechanisms that include hierarchical control of actuators, switched control of power flow and some transduction principles. Firstly, some biological models are introduced as a source of inspiration for setting up both actuation principles and control technologies. Secondly, a particular actuator technology, the travelling wave ultrasonic motor, is taken to illustrate this approach. Eventually, the last section draws some conclusions and points out future directions.

  11. Soft Robotic Actuators (United States)

    Godfrey, Juleon Taylor

    In this thesis a survey on soft robotic actuators is conducted. The actuators are classified into three main categories: Pneumatic Artificial Muscles (PAM), Electronic Electroactive Polymers (Electric EAP), and Ionic Electroactive Polymers (Ionic EAP). Soft robots can have many degrees and are more compliant than hard robots. This makes them suitable for applications that are difficult for hard robots. For each actuator background history, build materials, how they operate, and modeling are presented. Multiple actuators in each class are reviewed highlighting both their use and their mathematical formulation. In addition to the survey the McKibben actuator was chosen for fabrication and in-depth experimental analysis. Four McKibben actuators were fabricated using mesh sleeve, barbed hose fittings, and different elastic bladders. All were actuated using compressed air. Tensile tests were performed for each actuator to measure the tension force as air pressure increased from 20 to 100 psi in 10 psi increments. To account for material relaxation properties eleven trials for each actuator were run for 2-3 days. In conclusion, the smallest outer diameter elastic bladder was capable of producing the highest force due to the larger gap between the bladder and the sleeve.

  12. Robust model reference adaptive output feedback tracking for uncertain linear systems with actuator fault based on reinforced dead-zone modification. (United States)

    Bagherpoor, H M; Salmasi, Farzad R


    In this paper, robust model reference adaptive tracking controllers are considered for Single-Input Single-Output (SISO) and Multi-Input Multi-Output (MIMO) linear systems containing modeling uncertainties, unknown additive disturbances and actuator fault. Two new lemmas are proposed for both SISO and MIMO, under which dead-zone modification rule is improved such that the tracking error for any reference signal tends to zero in such systems. In the conventional approach, adaption of the controller parameters is ceased inside the dead-zone region which results tracking error, while preserving the system stability. In the proposed scheme, control signal is reinforced with an additive term based on tracking error inside the dead-zone which results in full reference tracking. In addition, no Fault Detection and Diagnosis (FDD) unit is needed in the proposed approach. Closed loop system stability and zero tracking error are proved by considering a suitable Lyapunov functions candidate. It is shown that the proposed control approach can assure that all the signals of the close loop system are bounded in faulty conditions. Finally, validity and performance of the new schemes have been illustrated through numerical simulations of SISO and MIMO systems in the presence of actuator faults, modeling uncertainty and output disturbance. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  13. Micro magnetic-actuators; Micro jiki actuator

    Energy Technology Data Exchange (ETDEWEB)

    Arai, K. [Tohoku University, Sendai (Japan). Research Institute of Electrical Communication; Honda, T. [Tokin Corporation, Tokyo (Japan)


    As the micromachine technology has attracted higher attention, the research and development of the technology is increasing. This paper describes the typical trial production samples of the electromagnetic type and magnetostrictive type actuators. The development of electromagnetic motors of the order of millimeters using the mechanical working technology is actively progressing. A report announced the axial gap motor 0.8 mm in outside diameter and 1.2 mm in height. The semiconductor micro machining technology was used to fabricate the reluctance motor (with the rotor 285 {mu}m in diameter). In this case, the LIGA process through the X-ray lithography was adopted. Some other types of micro magnetic-actuators were produced by using magnetic field gradient and magnetic torque. The magnetostrictive actuator is emerging to the market, drawing attention of the industry. This type of actuator utilizes the phenomenon that the dimensions vary when a magnetic field is applied to a magnetic substance. Samples applying high magnetic thin film include the cantilever type actuator and the travelling machine. 19 refs., 9 figs.

  14. The Energy Amplification Characteristic Research of a Multimodal Actuator

    Directory of Open Access Journals (Sweden)

    Han Yali


    Full Text Available A multimodal actuator is proposed to fulfil the different walking patterns of a power-assisted knee exoskeleton. With this actuator, the exoskeleton leg can realize several modes of operation, including series elastic actuation, stiff position control and energy storage and release. The energy amplification characteristics of the multimodal actuator in the series elastic mode are analysed. A dynamics model was established to study how series elasticity and the equivalent mass of transmission influence a power source, such as an electric motor. The results, in both simulation and experiment, show that series elasticity can amplify actuator power output, and the power output of a multimodal actuator is greater when the equivalent mass of the transmission mechanism is smaller. This research into multimodal actuator energy amplification supplies important insights into the design of artificial systems that can more closely approximate the performance of biological systems.

  15. Stick and slip actuators (SSA) (United States)

    Schmitt, Carl; Breguet, Jean-Marc; Bergander, Arvid; Clavel, Reymond


    Stick and Skip Actuators (SSA) are particularly well adapted to micro- robotics. A simple design, a very high intrinsic resolution (a few nanometers) and a high rigidity make them especially interesting in high precision micro-manipulations. Moreover, a smart design allows to combine the guiding and actuating function. The mechanical interface between the piezo-elements and the guiding mechanisms in an important point of the stick and slip actuators. The design of this interface and the choice of the material are very important. Both aspects have an impact on the rigidity, which has an influence on the behavior of the actuator. They have also an incidence onf the reliability (lifetime) because the design gives the contact condition and the material the wear resistance. In addition, a loading system allowing to keep the mechanical contact at this interface has a direct effect on the contact pressure. In order to confirm the performance of SSA, prototypes have been developed at the ISR. Their designs have bene made for application in optical microscopy, for manipulators in industrial assembly of micro- engineering products, for micro-factory, chemical and bio-engineering equipment for research or routine tasks, such as testing, screening etc. This paper presents a short description of several SSA made by the IRS and describes the parameters characterizing the stick and slip motion and the mechanical interface.

  16. Flexible printed circuit board actuators (United States)

    Lee, Junseok; Cha, Youngsu


    Out-of-plane actuators are made possible by the breaking of planar symmetry. In this paper, we present a thin-film out-of-plane electrostatic actuator for a flexible printed circuit board (FPCB) that can be fabricated with a single step of the conventional manufacturing process. No other components are required for actuation except a single sheet of the FPCB, and it works based on the planar asymmetry resulting from asymmetrically patterned top and bottom electrodes on each side of the polyimide film. With the structural asymmetry, the application of a high voltage in the order of kilovolts results in the asymmetry of the electric fields and the body force density, which generates the bending moment that leads to macroscopic deformations. We applied the finite element method to examine the asymmetry induced by the difference in the electrodes. In the experiment, the displacement responses to step input and square wave input of various frequencies were analyzed. It was found that our actuator constitutes an underdamped system, exhibiting resonance characteristics. The maximum oscillatory amplitude was determined at resonance, and the relationship between the displacement and the applied voltage was investigated.

  17. Multilayer Piezoelectric Stack Actuator Characterization (United States)

    Sherrit, Stewart; Jones, Christopher M.; Aldrich, Jack B.; Blodget, Chad; Bao, Xioaqi; Badescu, Mircea; Bar-Cohen, Yoseph


    Future NASA missions are increasingly seeking to use actuators for precision positioning to accuracies of the order of fractions of a nanometer. For this purpose, multilayer piezoelectric stacks are being considered as actuators for driving these precision mechanisms. In this study, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and extreme temperatures and voltages. AC signal testing included impedance, capacitance and dielectric loss factor of each actuator as a function of the small-signal driving sinusoidal frequency, and the ambient temperature. DC signal testing includes leakage current and displacement as a function of the applied DC voltage. The applied DC voltage was increased to over eight times the manufacturers' specifications to investigate the correlation between leakage current and breakdown voltage. Resonance characterization as a function of temperature was done over a temperature range of -180C to +200C which generally exceeded the manufacturers' specifications. In order to study the lifetime performance of these stacks, five actuators from one manufacturer were driven by a 60volt, 2 kHz sine-wave for ten billion cycles. The tests were performed using a Lab-View controlled automated data acquisition system that monitored the waveform of the stack electrical current and voltage. The measurements included the displacement, impedance, capacitance and leakage current and the analysis of the experimental results will be presented.

  18. Electrochemical micro actuator

    NARCIS (Netherlands)

    Hamberg, M.W.; Hamberg, M.W.; Rusu, C.R.; Gardeniers, Johannes G.E.; Ijntema, D.J.; IJntema, D.J.; Elwenspoek, Michael Curt


    In this paper an investigation of the feasibility of a new electrochemical micro actuator is presented. The actuator is fabricated using silicon micro-machining techniques. A gas pressure is generated by electrolysis of an aqueous electrolyte solution. The build up pressure is used to change the

  19. Sensors and actuators, Twente

    NARCIS (Netherlands)

    Bergveld, Piet


    This paper describes the organization and the research programme of the Sensor and Actuator (S&A) Research Unit of the University of Twente, Enschede, the Netherlands. It includes short descriptions of all present projects concerning: micromachined mechanical sensors and actuators, optical sensors,

  20. Pneumatically actuated hand tool

    NARCIS (Netherlands)

    Cool, J.C.; Rijnsaardt, K.A.


    Abstract of NL 9401195 (A) Pneumatically actuated hand tool for carrying out a mechanical operation, provided with an exchangeable gas cartridge in which the gas which is required for pneumatic actuation is stored. More particularly, the hand tool is provided with at least one pneumatic motor, at

  1. Conjugated Polymers as Actuators: Modes of Actuation

    DEFF Research Database (Denmark)

    Skaarup, Steen

    The physical and chemical properties of conjugated polymers often depend very strongly on the degree of doping with anions or cations. The movement of ions in and out of the polymer matrix as it is redox cycled is also accompanied by mechanical changes. Both the volume and the stiffness can exhibit...... significant differences between the oxidized and reduced states. These effects form the basis of the use of conjugated polymers as actuators (or “artificial muscles”) controllable by a small (1-10 V) voltage. Three basic modes of actuation (bending, linear extension and stiffness change) have been proposed....... This work discusses their relative merits and possible areas of application....

  2. Conjugated polymers as actuators: modes of actuation

    DEFF Research Database (Denmark)

    Skaarup, Steen


    The physical and chemical properties of conjugated polymers often depend very strongly on the degree of doping with anions or cations. The movement of ions in and out of the polymer matrix as it is redox cycled is also accompanied by mechanical changes. Both the volume and the stiffness can exhibit...... significant differences between the oxidized and reduced states. These effects form the basis of the use of conjugated polymers as actuators (or “artificial muscles”) controllable by a small (1-10 V) voltage. Three basic modes of actuation (bending, linear extension and stiffness change) have been proposed....... This work discusses their relative merits and possible areas of application....

  3. Position and torque tracking: series elastic actuation versus model-based-controlled hydraulic actuation. (United States)

    Otten, Alexander; van Vuuren, Wieke; Stienen, Arno; van Asseldonk, Edwin; Schouten, Alfred; van der Kooij, Herman


    Robotics used for diagnostic measurements on, e.g. stroke survivors, require actuators that are both stiff and compliant. Stiffness is required for identification purposes, and compliance to compensate for the robots dynamics, so that the subject can move freely while using the robot. A hydraulic actuator can act as a position (stiff) or a torque (compliant) actuator. The drawback of a hydraulic actuator is that it behaves nonlinear. This article examines two methods for controlling a nonlinear hydraulic actuator. The first method that is often applied uses an elastic element (i.e. spring) connected in series with the hydraulic actuator so that the torque can be measured as the deflection of the spring. This torque measurement is used for proportional integral control. The second method of control uses the inverse of the model of the actuator as a linearizing controller. Both methods are compared using simulation results. The controller designed for the series elastic hydraulic actuator is faster to implement, but only shows good performance for the working range for which the controller is designed due to the systems nonlinear behavior. The elastic element is a limiting factor when designing a position controller due to its low torsional stiffness. The model-based controller linearizes the nonlinear system and shows good performance when used for torque and position control. Implementing the model-based controller does require building and validating of the detailed model. © 2011 IEEE

  4. Variable Valve Actuation

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey Gutterman; A. J. Lasley


    Many approaches exist to enable advanced mode, low temperature combustion systems for diesel engines - such as premixed charge compression ignition (PCCI), Homogeneous Charge Compression Ignition (HCCI) or other HCCI-like combustion modes. The fuel properties and the quantity, distribution and temperature profile of air, fuel and residual fraction in the cylinder can have a marked effect on the heat release rate and combustion phasing. Figure 1 shows that a systems approach is required for HCCI-like combustion. While the exact requirements remain unclear (and will vary depending on fuel, engine size and application), some form of substantially variable valve actuation is a likely element in such a system. Variable valve actuation, for both intake and exhaust valve events, is a potent tool for controlling the parameters that are critical to HCCI-like combustion and expanding its operational range. Additionally, VVA can be used to optimize the combustion process as well as exhaust temperatures and impact the after treatment system requirements and its associated cost. Delphi Corporation has major manufacturing and product development and applied R&D expertise in the valve train area. Historical R&D experience includes the development of fully variable electro-hydraulic valve train on research engines as well as several generations of mechanical VVA for gasoline systems. This experience has enabled us to evaluate various implementations and determine the strengths and weaknesses of each. While a fully variable electro-hydraulic valve train system might be the 'ideal' solution technically for maximum flexibility in the timing and control of the valve events, its complexity, associated costs, and high power consumption make its implementation on low cost high volume applications unlikely. Conversely, a simple mechanical system might be a low cost solution but not deliver the flexibility required for HCCI operation. After modeling more than 200 variations of

  5. Enzyme actuated bioresponsive hydrogels (United States)

    Wilson, Andrew Nolan

    Bioresponsive hydrogels are emerging with technological significance in targeted drug delivery, biosensors and regenerative medicine. Conferred with the ability to respond to specific biologically derived stimuli, the design challenge is in effectively linking the conferred biospecificity with an engineered response tailored to the needs of a particular application. Moreover, the fundamental phenomena governing the response must support an appropriate dynamic range and limit of detection. The design of these systems is inherently complicated due to the high interdependency of the governing phenomena that guide the sensing, transduction, and the actuation response of hydrogels. To investigate the dynamics of these materials, model systems may be used which seek to interrogate the system dynamics by uni-variable experimentation and limit confounding phenomena such as: polymer-solute interactions, polymer swelling dynamics and biomolecular reaction-diffusion concerns. To this end, a model system, alpha-chymotrypsin (Cht) (a protease) and a cleavable peptide-chromogen (pro-drug) covalently incorporated into a hydrogel, was investigated to understand the mechanisms of covalent loading and release by enzymatic cleavage in bio-responsive delivery systems. Using EDC and Sulfo-NHS, terminal carboxyl groups of N-succinyl-Ala-Ala-Pro-Phe p-nitroanilide, a cleavable chromogen, were conjugated to primary amines of a hydrated poly(HEMA)-based hydrogel. Hydrogel discs were incubated in buffered Cht causing enzyme-mediated cleavage of the peptide and concomitant release of the chromophore for monitoring. To investigate substrate loading and the effects of hydrogel morphology on the system, the concentration of the amino groups (5, 10, 20, and 30 mol%) and the cross-linked density (1, 5, 7, 9 and 12 mol%) were independently varied. Loading-Release Efficiency of the chromogen was shown to exhibit a positive relation to increasing amino groups (AEMA). The release rates demonstrated a

  6. Another Lesson from Plants: The Forward Osmosis-Based Actuator (United States)

    Sinibaldi, Edoardo; Argiolas, Alfredo; Puleo, Gian Luigi; Mazzolai, Barbara


    Osmotic actuation is a ubiquitous plant-inspired actuation strategy that has a very low power consumption but is capable of generating effective movements in a wide variety of environmental conditions. In light of these features, we aimed to develop a novel, low-power-consumption actuator that is capable of generating suitable forces during a characteristic actuation time on the order of a few minutes. Based on the analysis of plant movements and on osmotic actuation modeling, we designed and fabricated a forward osmosis-based actuator with a typical size of 10 mm and a characteristic time of 2–5 minutes. To the best of our knowledge, this is the fastest osmotic actuator developed so far. Moreover, the achieved timescale can be compared to that of a typical plant cell, thanks to the integrated strategy that we pursued by concurrently addressing and solving design and material issues, as paradigmatically explained by the bioinspired approach. Our osmotic actuator produces forces above 20 N, while containing the power consumption (on the order of 1 mW). Furthermore, based on the agreement between model predictions and experimental observations, we also discuss the actuator performance (including power consumption, maximum force, energy density and thermodynamic efficiency) in relation to existing actuation technologies. In light of the achievements of the present study, the proposed osmotic actuator holds potential for effective exploitation in bioinspired robotics systems. PMID:25020043

  7. Prognostics Enhanced Reconfigurable Control of Electro-Mechanical Actuators (United States)

    National Aeronautics and Space Administration — Actuator systems are employed widely in aerospace, transportation and industrial processes to provide power to critical loads, such as aircraft control surfaces....

  8. Energy Efficient Wireless Vehicular-Guided Actuator Network

    KAUST Repository

    Boudellioua, Imene


    In this paper, we present an energy-efficient vehicular guided system for environmental disaster management using wireless sensor/actuator networks. Sensor nodes within clusters are controlled by a master node that is dynamically selected. Actuators support mobility for every sensor node in the area of interest. The system maintains energy efficiency using statistical, correlation, and confidence for determining actuator actions and implements an adaptive energy scheme to prolong the system lifespan. Experimental results show that the system is capable of saving up to 2.7Watt for every 28KByte of data exchanged. We also show that actuator actions are correct with a 90% confidence.

  9. Cryogenic Piezoelectric Actuator (United States)

    Jiang, Xiaoning; Cook, William B.; Hackenberger, Wesley S.


    In this paper, PMN-PT single crystal piezoelectric stack actuators and flextensional actuators were designed, prototyped and characterized for space optics applications. Single crystal stack actuators with footprint of 10 mm x10 mm and the height of 50 mm were assembled using 10 mm x10mm x0.15mm PMN-PT plates. These actuators showed stroke > 65 - 85 microns at 150 V at room temperature, and > 30 microns stroke at 77 K. Flextensional actuators with dimension of 10mm x 5 mm x 7.6 mm showed stroke of >50 microns at room temperature at driving voltage of 150 V. A flextensional stack actuator with dimension of 10 mm x 5 mm x 47 mm showed stroke of approx. 285 microns at 150 V at room temperature and > 100 microns at 77K under driving of 150 V should be expected. The large cryogenic stroke and high precision of these actuators are promising for cryogenic optics applications.

  10. Multi-Objective Sliding Mode Control on Vehicle Cornering Stability with Variable Gear Ratio Actuator-Based Active Front Steering Systems

    Directory of Open Access Journals (Sweden)

    Xinbo Ma


    Full Text Available Active front steering (AFS is an emerging technology to improve the vehicle cornering stability by introducing an additional small steering angle to the driver’s input. This paper proposes an AFS system with a variable gear ratio steering (VGRS actuator which is controlled by using the sliding mode control (SMC strategy to improve the cornering stability of vehicles. In the design of an AFS system, different sensors are considered to measure the vehicle state, and the mechanism of the AFS system is also modelled in detail. Moreover, in order to improve the cornering stability of vehicles, two dependent objectives, namely sideslip angle and yaw rate, are considered together in the design of SMC strategy. By evaluating the cornering performance, Sine with Dwell and accident avoidance tests are conducted, and the simulation results indicate that the proposed SMC strategy is capable of improving the cornering stability of vehicles in practice.

  11. Magnetically Actuated Seal Project (United States)

    National Aeronautics and Space Administration — FTT proposes development of a magnetically actuated dynamic seal. Dynamic seals are used throughout the turbopump in high-performance, pump-fed, liquid rocket...

  12. Rotary Series Elastic Actuator (United States)

    Ihrke, Chris A. (Inventor); Mehling, Joshua S. (Inventor); Parsons, Adam H. (Inventor); Griffith, Bryan Kristian (Inventor); Radford, Nicolaus A. (Inventor); Permenter, Frank Noble (Inventor); Davis, Donald R. (Inventor); Ambrose, Robert O. (Inventor); Junkin, Lucien Q. (Inventor)


    A rotary actuator assembly is provided for actuation of an upper arm assembly for a dexterous humanoid robot. The upper arm assembly for the humanoid robot includes a plurality of arm support frames each defining an axis. A plurality of rotary actuator assemblies are each mounted to one of the plurality of arm support frames about the respective axes. Each rotary actuator assembly includes a motor mounted about the respective axis, a gear drive rotatably connected to the motor, and a torsion spring. The torsion spring has a spring input that is rotatably connected to an output of the gear drive and a spring output that is connected to an output for the joint.

  13. Laser Initiated Actuator study

    Energy Technology Data Exchange (ETDEWEB)

    Watson, B.


    The program task was to design and study a laser initiated actuator. The design of the actuator is described, it being comprised of the fiber and body subassemblies. The energy source for all experiments was a Spectra Diode 2200-H2 laser diode. The diode is directly coupled to a 100 micron core, 0.3 numerical aperture fiber optic terminated with an SMA connector. The successful testing results are described and recommendations are made.

  14. Soft actuators and soft actuating devices

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Dian; Whitesides, George M.


    A soft buckling linear actuator is described, including: a plurality of substantially parallel bucklable, elastic structural components each having its longest dimension along a first axis; and a plurality of secondary structural components each disposed between and bridging two adjacent bucklable, elastic structural components; wherein every two adjacent bucklable, elastic structural components and the secondary structural components in-between define a layer comprising a plurality of cells each capable of being connected with a fluid inflation or deflation source; the secondary structural components from two adjacent layers are not aligned along a second axis perpendicular to the first axis; and the secondary structural components are configured not to buckle, the bucklable, elastic structural components are configured to buckle along the second axis to generate a linear force, upon the inflation or deflation of the cells. Methods of actuation using the same are also described.

  15. Behavioral responses of Arctica islandica (Bivalvia: Arcticidae) to simulated leakages of carbon dioxide from sub-sea geological storage

    Energy Technology Data Exchange (ETDEWEB)

    Bamber, Shaw D., E-mail:; Westerlund, Stig, E-mail:


    Highlights: • Valve pumping activity in A. islandica significantly increased at pH 6.2 seawater. • Changes in valve movements were not related to attempted burrowing activities. • Valve activity returned to control levels after 5 days of continuous exposure. • A. islandica tolerate pH reductions likely to follow leakage of sub-sea stored CO{sub 2}. - Abstract: Sub-sea geological storage of carbon dioxide (CO{sub 2}) provides a viable option for the Carbon Capture and Storage (CCS) approach for reducing atmospheric emissions of this greenhouse gas. Although generally considered to offer a low risk of major leakage, it remains relevant to establish the possible consequences for marine organisms that live in or on sediments overlying these storage areas if such an event may occur. The present study has used a series of laboratory exposures and behavioral bioassays to establish the sensitivity of Arctica islandica to simulated leakages of CO{sub 2}. This long-lived bivalve mollusc is widely distributed throughout the North Sea, an area where geological storage is currently taking place and where there are plans to expand this operation significantly. A recently published model has predicted a maximum drop of 1.9 pH units in seawater at the point source of a substantial escape of CO{sub 2} from sub-sea geological storage in this region. Valve movements of A. islandica exposed to reduced pH seawater were recorded continuously using Hall effect proximity sensors. Valve movement regulation is important for optimising the flow of water over the gills, which supplies food and facilitates respiration. A stepwise reduction in seawater pH showed an initial increase in both the rate and extent of valve movements in the majority of individuals tested when pH fell to 6.2 units. Exposing A. islandica to pH 6.2 seawater continuously for seven days resulted in a clear increase in valve movements during the first 40 h of exposure, followed by a gradual reduction in activity

  16. System Modeling and Operational Characteristic Analysis for an Orbital Friction Vibration Actuator Used in Orbital Vibration Welding

    Directory of Open Access Journals (Sweden)

    XU, F.


    Full Text Available Orbital Friction Vibration Actuator (OFVA is a core component of Orbital Friction Welding (OFW, which is a novel apertureless welding technology utilizing friction heat to implement solid-state joining. In this paper, topology and operational principle of OFVA are introduced, the analytical formulas of the electromagnetic force for the x and y directions, which can drive the mover to generate a circular motion trajectory, are derived, and the characteristic of static electromagnetic force is predicted by analytical method and 2-D (two-dimensional FEM (finite element method, 3-D and measurement. The coupled magnetic field-circuit-motion simulation models which are driven by current and voltage source are established, respectively, and some of its operational characteristics are analyzed. Simulation and experiment validate theoretical analysis and the feasibility of the fabricated prototype, demonstrate the good performance of the OFVA, and provide valuable reference for engineering applications.

  17. Geographic information systems supporting the solution of emergencies and their connection to self-actuated notification systems (United States)

    Reil, Adam; Bureš, Luděk; Roub, Radek; Hejduk, Tomáš; Novák, Pavel


    Geographic information systems represent an important tool in supporting the operation and crisis management of Integrated Rescue System (IRS) branches. The technology of geographic information systems makes it possible to localize specific information directly in the concerned area. A basic pre-requisite for efficient IRS functioning is the identification of so-called critical points in the given territory. The next step is the identification of endangered persons and properties. In these issues, emphasis is put particularly on the time scale, which represents a key aspect of the crisis management. In case of flood danger, the Early Flood Warning Service would inform flood authorities responsible for warning the population, declaring flood activity degrees, IRS activation and organization. For their decision-making, the flood authorities need data on level heights, current discharge rates and inundation areas. The information about discharge rates and height levels can be obtained from the network of recording stream gauge stations operated by the Czech Hydrometeorological Institute. Inundation areas are plotted in the flood control plans of municipalities, which however contain default information about areas flooded at the N-year flood discharges Q5, Q20 and Q100. Because of large intervals, these three scenarios are insufficient for the crisis management of larger communities and towns. Therefore, a data store was suggested that would include maps showing flow rate fields and inundation areas for a finer scale of flood discharges at regular intervals. The scale should be based on the N-year flood discharges with a possibility of extension if required by flood authorities. The discharge interval size should be selected with regard to the dynamics of level height change in the given watercourse. The inundation areas will be then established by way of calculation using the MIKE 21C 2D hydrodynamic model. The novel approach was applied recently in the cadastral

  18. Design and fabrication of a hybrid actuator (United States)

    Fu, Yao; Ghantasala, Muralidhar K.; Harvey, Erol; Qin, Lijiang


    The necessity to reduce the size of actuators and at the same time increase the force and the air gap has placed severe constraints on the suitability of current microactuator technology for various applications. This has led to the development of new actuator technologies based on novel materials or modifying existing systems. As an effort in this direction, we are reporting on the design and fabrication of a hybrid actuator employing a combination of electromagnetic and piezoelectric actuation methods for the first time. This actuator was designed and optimized by using the piezoelectric and electromagnetic solvers of commercially available FEM software packages (CoventorWare and ANSYS). The device consists of a shaped piezoelectric composite cantilever on the top and a copper coil wound around a permalloy core assembled on a silicon substrate with a permanent magnet at the bottom. The composite cantilever consists of polarized piezoelectric polymer polyvinylidene fluoride (PVDF) with an electroplated permalloy layer on one side. Microstructures in the required shape are introduced using novel methodologies including laser micromachining and microembossing. The hybrid actuator has been fabricated and tested using standard testing procedures. The experimental data are compared with the simulation results from both the finite element methods and the analytical model. There is excellent agreement between the results obtained in simulation and by experiment. A maximum total deflection of 400 µm with a typical contact force of 200 µN has been achieved.


    Directory of Open Access Journals (Sweden)

    A. Moosavi


    Full Text Available An actuator is a device that converts input energy into mechanical energy. According to various types of input energy, various actuators have been advanced. Displacement in the electromagnetic, hydraulic and pneumatic actuators achieve by moving a piston via electromagnetic force or pressure, however the piezoelectric actuator (piezoceramic plates displace directly. Therefore, accuracy and speed in the piezoelectric device are higher than other types of actuators. In the present work, the high-field electromechanical response of high-quality (1−x(Bi 0.5Na0.5TiO3–x(Bi0.5K0.5TiO3 samples abbreviated to BNKTx with x = 0.18, 0.20, 0.22 and 0.24 ceramic materials across its MPB was investigated. The piezoelectrics and actuation characteristics were characterized. Ourresults indicate that x = 0.20, indeed, constitutes the best choice for the MPB composition in the system. Maximum of remanent polarization (37.5 μC cm−2 was obtained for x=0.20. High-field electromechanical responses were also obtained for BNKT0.20 samples. This material exhibited giant field induced strains of 0.13% under 1 kV mm -1 at room temperature.

  20. Recent developments on SMA actuators: predicting the actuation fatigue life for variable loading schemes (United States)

    Wheeler, Robert W.; Lagoudas, Dimitris C.


    Shape memory alloys (SMAs), due to their ability to repeatably recover substantial deformations under applied mechanical loading, have the potential to impact the aerospace, automotive, biomedical, and energy industries as weight and volume saving replacements for conventional actuators. While numerous applications of SMA actuators have been flight tested and can be found in industrial applications, these actuators are generally limited to non-critical components, are not widely implemented and frequently one-off designs, and are generally overdesigned due to a lack of understanding of the effect of the loading path on the fatigue life and the lack of an accurate method for predicting actuator lifetimes. In recent years, multiple research efforts have increased our understanding of the actuation fatigue process of SMAs. These advances can be utilized to predict the fatigue lives and failure loads in SMA actuators. Additionally, these prediction methods can be implemented in order to intelligently design actuators in accordance with their fatigue and failure limits. In the following paper, both simple and complex thermomechanical loading paths have been considered. Experimental data was utilized from two material systems: equiatomic Nickel-Titanium and Nickelrich Nickel-Titanium.

  1. Digital Actuator Technology

    Energy Technology Data Exchange (ETDEWEB)

    Ken Thomas; Ted Quinn; Jerry Mauck; Richard Bockhorst


    There are significant developments underway in new types of actuators for power plant active components. Many of these make use of digital technology to provide a wide array of benefits in performance of the actuators and in reduced burden to maintain them. These new product offerings have gained considerable acceptance in use in process plants. In addition, they have been used in conventional power generation very successfully. This technology has been proven to deliver the benefits promised and substantiate the claims of improved performance. The nuclear industry has been reluctant to incorporate digital actuator technology into nuclear plant designs due to concerns due to a number of concerns. These could be summarized as cost, regulatory uncertainty, and a certain comfort factor with legacy analog technology. The replacement opportunity for these types of components represents a decision point for whether to invest in more modern technology that would provide superior operational and maintenance benefits. Yet, the application of digital technology has been problematic for the nuclear industry, due to qualification and regulatory issues. With some notable exceptions, the result has been a continuing reluctance to undertake the risks and uncertainties of implementing digital actuator technology when replacement opportunities present themselves. Rather, utilities would typically prefer to accept the performance limitations of the legacy analog actuator technologies to avoid impacts to project costs and schedules. The purpose of this report is to demonstrate that the benefits of digital actuator technology can be significant in terms of plant performance and that it is worthwhile to address the barriers currently holding back the widespread development and use of this technology. It addresses two important objectives in pursuit of the beneficial use of digital actuator technology for nuclear power plants: 1. To demonstrate the benefits of digital actuator

  2. Low-Stroke Actuation for a Serial Robot (United States)

    Gao, Dalong (Inventor); Ihrke, Chris A. (Inventor)


    A serial robot includes a base, first and second segments, a proximal joint joining the base to the first segment, and a distal joint. The distal joint that joins the segments is serially arranged and distal with respect to the proximal joint. The robot includes first and second actuators. A first tendon extends from the first actuator to the proximal joint and is selectively moveable via the first actuator. A second tendon extends from the second actuator to the distal joint and is selectively moveable via the second actuator. The robot includes a transmission having at least one gear element which assists rotation of the distal joint when an input force is applied to the proximal and/or distal joints by the first and/or second actuators. A robotic hand having the above robot is also disclosed, as is a robotic system having a torso, arm, and the above-described hand.

  3. The Load Capability of Piezoelectric Single Crystal Actuators (United States)

    Xu, Tian-Bing; Su, Ji; Jiang, Xiaoning; Rehrig, Paul W.; Hackenberger, Wesley S.


    Piezoelectric lead magnesium niobate-lead titanate (PMN-PT) single crystal is one of the most promising materials for electromechanical device applications due to its high electrical field induced strain and high electromechanical coupling factor. PMN-PT single crystal-based multilayer stack actuators and multilayer stack-based flextensional actuators have exhibited high stroke and high displacement-voltage ratios. The actuation capabilities of these two actuators were evaluated using a newly developed method based upon a laser vibrometer system under various loading conditions. The measured displacements as a function of mechanical loads at different driving voltages indicate that the displacement response of the actuators is approximately constant under broad ranges of mechanical load. The load capabilities of these PMN-PT single crystal-based actuators and the advantages of the capability for applications will be discussed.

  4. Shape Memory Actuated Normally Open Permanent Isolation Valve (United States)

    Ramspacher, Daniel J. (Inventor); Bacha, Caitlin E. (Inventor)


    A valve assembly for an in-space propulsion system includes an inlet tube, an outlet tube, a valve body coupling the inlet tube to the outlet tube and defining a propellant flow path, a valve stem assembly disposed within the valve body, an actuator body coupled to the valve body, the valve stem assembly extending from an interior of the valve body to an interior of the actuator body, and an actuator assembly disposed within the actuator body and coupled to the valve stem assembly, the actuator assembly including a shape memory actuator member that when heated to a transition temperature is configured to enable the valve stem assembly to engage the outlet tube and seal the propellant flow path.

  5. Extended state observer–based fractional order proportional–integral–derivative controller for a novel electro-hydraulic servo system with iso-actuation balancing and positioning

    Directory of Open Access Journals (Sweden)

    Qiang Gao


    Full Text Available Aiming at balancing and positioning of a new electro-hydraulic servo system with iso-actuation configuration, an extended state observer–based fractional order proportional–integral–derivative controller is proposed in this study. To meet the lightweight requirements of heavy barrel weapons with large diameters, an electro-hydraulic servo system with a three-chamber hydraulic cylinder is especially designed. In the electro-hydraulic servo system, the balance chamber of the hydraulic cylinder is used to realize active balancing of the unbalanced forces, while the driving chambers consisting of the upper and lower chambers are adopted for barrel positioning and dynamic compensation of external disturbances. Compared with conventional proportional–integral–derivative controllers, the fractional order proportional–integral–derivative possesses another two adjustable parameters by expanding integer order to arbitrary order calculus, resulting in more flexibility and stronger robustness of the control system. To better compensate for strong external disturbances and system nonlinearities, the extended state observer strategy is further introduced to the fractional order proportional–integral–derivative control system. Numerical simulation and bench test indicate that the extended state observer–based fractional order proportional–integral–derivative significantly outperforms proportional–integral–derivative and fractional order proportional–integral–derivative control systems with better control accuracy and higher system robustness, well demonstrating the feasibility and effectiveness of the proposed extended state observer–based fractional order proportional–integral–derivative control strategy.

  6. A dynamic linearization concept for piezoelectric actuators. (United States)

    Biancuzzi, Giovanni; Haller, Daniel; Lemke, Thomas; Wischke, Martin; Goldschmidtboeing, Frank; Woias, Peter


    We present a linearization circuit based on a capacitive Wheatstone bridge that is able to set a desired polarization in a piezoactuator. The system is meant to be used for dynamic actuation in a broad frequency range. A general nonlinear model for piezoactuators is presented in which two nonlinear sub-systems are cascaded: the electric-field-to-polarization (E-P) and the polarization-to-strain (P-x) blocks. The inversion of the latter sub-system in combination with the linearization bridge results in a reduction of up to 19 dB of the harmonic distortion of the actuator's mechanical displacement. © 2011 IEEE

  7. Scientific Research Program for Power, Energy, and Thermal Technologies. Task Order 0001: Energy, Power, and Thermal Technologies and Processes Experimental Research. Subtask: Thermal Management of Electromechanical Actuation System for Aircraft Primary Flight Control Surfaces (United States)


    4 HPU Supply and Return Valves ..................................................................................85 Figure C-5 Water Valves at Pump...Computer FHPCP Flexible Heat Pipe Cold Plate HPEAS High Performance Electric Actuation System HPU Hydraulic Power Unit HSM Hydraulic Service...commanded speed setpoint. A MTS hydraulic press assembly made up of a hydraulic power unit ( HPU 505G2), hydraulic service manifold (HSM 292.22

  8. An algorithm for LQ optimal actuator location (United States)

    Darivandi, Neda; Morris, Kirsten; Khajepour, Amir


    The locations of the control hardware are typically a design variable in controller design for distributed parameter systems. In order to obtain the most efficient control system, the locations of control hardware as well as the feedback gain should be optimized. These optimization problems are generally non-convex. In addition, the models for these systems typically have a large number of degrees of freedom. Consequently, existing optimization schemes for optimal actuator placement may be inaccurate or computationally impractical. In this paper, the feedback control is chosen to be an optimal linear quadratic regulator. The optimal actuator location problem is reformulated as a convex optimization problem. A subgradient-based optimization scheme which leads to the global solution of the problem is used to optimize actuator locations. The optimization algorithm is applied to optimize the placement of piezoelectric actuators in vibration control of flexible structures. This method is compared with a genetic algorithm, and is observed to be faster and more accurate. Experiments are performed to verify the efficacy of optimal actuator placement.

  9. Stable electroosmotically driven actuators (United States)

    Sritharan, Deepa; Motsebo, Mylene; Tumbic, Julia; Smela, Elisabeth


    We have previously presented "nastic" actuators based on electroosmotic (EO) pumping of fluid in microchannels using high electric fields for potential application in soft robotics. In this work we address two challenges facing this technology: applying EO to meso-scale devices and the stability of the pumping fluid. The hydraulic pressure achieved by EO increases with as 1/d2, where d is the depth of the microchannel, but the flow rate (which determines the stroke and the speed) is proportional to nd, where n is the number of channels. Therefore to get high force and high stroke the device requires a large number of narrow channels, which is not readily achievable using standard microfabrication techniques. Furthermore, for soft robotics the structure must be soft. In this work we present a method of fabricating a three-dimensional porous elastomer to serve as the array of channels based on a sacrificial sugar scaffold. We demonstrate the concept by fabricating small pumps. The flexible devices were made from polydimethylsiloxane (PDMS) and comprise the 3D porous elastomer flanked on either side by reservoirs containing electrodes. The second issue addressed here involves the pumping fluid. Typically, water is used for EO, but water undergoes electrolysis even at low voltages. Since EO takes place at kV, these systems must be open to release the gases. We have recently reported that propylene carbonate (PC) is pumped at a comparable rate as water and is also stable for over 30 min at 8 kV. Here we show that PC is, however, degraded by moisture, so future EO systems must prevent water from reaching the PC.

  10. Exploring dielectric elastomers as actuators for hand tremor suppression (United States)

    Kelley, Christopher R.; Kauffman, Jeffrey L.


    Pathological tremor results in undesired motion of body parts, with the greatest effect typically occurring in the hands. Since common treatment methods are ineffective in some patients or have risks associated with surgery or side effects, researchers are investigating mechanical means of tremor suppression. This work explores the viability of dielectric elastomers as the actuators in a tremor suppression control system. Dielectric elastomers have many properties similar to human muscle, making them a natural fit for integration into the human biomechanical system. This investigation develops a model of the integrated wrist-actuator system to determine actuator parameters that produce the necessary control authority without significantly affecting voluntary motion. Furthermore, this paper develops a control law for the actuator voltage to increase the effective viscous damping of the system. Simulations show excellent theoretical tremor suppression, demonstrating the potential for dielectric elastomers to suppress tremor while maximizing compatibility between the actuator and the human body.

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

    Directory of Open Access Journals (Sweden)

    Maziar Ahmad Sharbafi


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

  12. Limit cycles and stiffness control with variable stiffness actuators

    NARCIS (Netherlands)

    Carloni, Raffaella; Marconi, Lorenzo


    Variable stiffness actuators realize highly dynamic systems, whose inherent mechanical compliance can be properly exploited to obtain a robust and energy-efficient behavior. The paper presents a control strategy for variable stiffness actuators with the primarily goal of tracking a limit cycle

  13. Modelling the nonlinearity of piezoelectric actuators in active ...

    African Journals Online (AJOL)

    Piezoelectric actuators have great capabilities as elements of intelligent structures for active vibration cancellation. One problem with this type of actuator is its nonlinear behaviour. In active vibration control systems, it is important to have an accurate model of the control branch. This paper demonstrates the ability of neural ...

  14. modelling the nonlinearity of piezoelectric actuators in active ...

    African Journals Online (AJOL)


    Piezoelectric actuators have great capabilities as elements of intelligent structures for active vibration cancellation. One problem with this type of actuator is its nonlinear behaviour. In active vibration control systems, it is important to have an accurate model of the control branch. This paper demonstrates the ability of neural ...

  15. A Magnetic Bead Actuator

    NARCIS (Netherlands)

    Derks, R.; Prins, M.W.J.; Wimberger-Friedl, R.


    Actuation principles of superparamagnetic beads applicable on biosensing (at single beads and chain orderning) are studied in this report. This research can be used to develop new techniques that are able to accelerate bio-assays. An experimental setup containing a sub-microliter fluid volume

  16. The Actuated Guitar

    DEFF Research Database (Denmark)

    Larsen, Jeppe Veirum; Overholt, Daniel; Moeslund, Thomas B.


    Playing a guitar is normally only for people with fully functional hands. In this work we investigate alternative interaction concepts to enable or re-enable people with non-functional right hands or arms to play a guitar via actuated strumming. The functionality and complexity of right hand...

  17. Bistable microelectromechanical actuator (United States)

    Fleming, J.G.


    A bistable microelectromechanical (MEM) actuator is formed on a substrate and includes a stressed membrane of generally rectangular shape that upon release assumes a curvilinear cross-sectional shape due to attachment at a midpoint to a resilient member and at opposing edges to a pair of elongate supports. The stressed membrane can be electrostatically switched between a pair of mechanical states having mirror-image symmetry, with the MEM actuator remaining in a quiescent state after a programming voltage is removed. The bistable MEM actuator according to various embodiments of the present invention can be used to form a nonvolatile memory element, an optical modulator (with a pair of mirrors supported above the membrane and moving in synchronism as the membrane is switched), a switchable mirror (with a single mirror supported above the membrane at the midpoint thereof) and a latching relay (with a pair of contacts that open and close as the membrane is switched). Arrays of bistable MEM actuators can be formed for applications including nonvolatile memories, optical displays and optical computing. 49 figs.

  18. Thermally Actuated Hydraulic Pumps (United States)

    Jones, Jack; Ross, Ronald; Chao, Yi


    Thermally actuated hydraulic pumps have been proposed for diverse applications in which direct electrical or mechanical actuation is undesirable and the relative slowness of thermal actuation can be tolerated. The proposed pumps would not contain any sliding (wearing) parts in their compressors and, hence, could have long operational lifetimes. The basic principle of a pump according to the proposal is to utilize the thermal expansion and contraction of a wax or other phase-change material in contact with a hydraulic fluid in a rigid chamber. Heating the chamber and its contents from below to above the melting temperature of the phase-change material would cause the material to expand significantly, thus causing a substantial increase in hydraulic pressure and/or a substantial displacement of hydraulic fluid out of the chamber. Similarly, cooling the chamber and its contents from above to below the melting temperature of the phase-change material would cause the material to contract significantly, thus causing a substantial decrease in hydraulic pressure and/or a substantial displacement of hydraulic fluid into the chamber. The displacement of the hydraulic fluid could be used to drive a piston. The figure illustrates a simple example of a hydraulic jack driven by a thermally actuated hydraulic pump. The pump chamber would be a cylinder containing encapsulated wax pellets and containing radial fins to facilitate transfer of heat to and from the wax. The plastic encapsulation would serve as an oil/wax barrier and the remaining interior space could be filled with hydraulic oil. A filter would retain the encapsulated wax particles in the pump chamber while allowing the hydraulic oil to flow into and out of the chamber. In one important class of potential applications, thermally actuated hydraulic pumps, exploiting vertical ocean temperature gradients for heating and cooling as needed, would be used to vary hydraulic pressures to control buoyancy in undersea research

  19. A novel, general-purpose, MR-compatible, manually actuated robotic manipulation system for minimally invasive interventions under direct MRI guidance. (United States)

    Christoforou, Eftychios G; Seimenis, Ioannis; Andreou, Eleni; Eracleous, Eleni; Tsekos, Nikolaos V


    Performing minimally invasive interventions under direct MRI guidance offers significant advantages. Required accessibility to the patient inside the MRI scanner is fairly limited, and employment of robotic assistance has been proposed. The development of MR-compatible robotic systems entails engineering challenges related to geometric constraints and the magnetic nature of the scanning environment. A novel, general-purpose, MR-compatible robotic manipulation system has been developed for the performance of minimally invasive interventions inside a cylindrical scanner under direct MRI guidance. The system is endowed with five degrees of freedom (DOF), is characterized by a unique kinematics structure and is manually actuated. The prototype system was shown to exhibit the required MR-compatibility characteristics and a task-space positioning ability of approximately 5 mm. Needle targeting testing demonstrated a 93% success rate in acquiring a 5 mm spherical target. Phantom testing was performed inside a 3 T scanner and results are reported for an experimental study simulating MRI-guided, manipulator-assisted, MR arthrography. Robotic assistance provided by the developed manipulator may effectively facilitate the performance of various MRI-guided, minimally invasive interventions inside a cylindrical scanner. Copyright © 2013 John Wiley & Sons, Ltd.

  20. Fabrication and reliable implementation of an ionic polymer-metal composite (IPMC) biaxial bending actuator (United States)

    Lee, Gil-Yong; Choi, Jung-Oh; Kim, Myeungseon; Ahn, Sung-Hoon


    Ionic polymer-metal composites (IPMCs) are one of the most popular types of electro-active polymer actuator, due to their low electric driving potential, large deformation range, and light weight. IPMCs have been used as actuators or sensors in many areas of biomedical and robotic engineering. In this research, IPMCs were studied as a biaxial bending actuator capable of smart and flexible motion. We designed and fabricated this bending actuator and implemented it to have a reliable actuating motion using a systematic approach. The resulting device was bar shaped with a square cross section and had four insulated electrodes on its surface. By applying different voltages to these four electrodes, a biaxial bending motion can be induced. To construct this actuator, several fabrication processes were considered. We modified the Nafion stacking method, and established a complete sequence of actuator fabrication processes. Using these processes, we were able to fabricate an IPMC biaxial bending actuator with both high actuating force and high flexibility. Several experiments were conducted to investigate and verify the performance of the actuator. The IPMC actuator system was modeled from experimentally measured data, and using this actuator model, a closed-loop proportional integral (PI) controller was designed. Reference position tracking performances of open-loop and closed-loop systems were compared. Finally, circular motion tracking performances of the actuator tip were tested under different rotation frequencies and radii of a reference trajectory circle.

  1. Investigation of electrochemical actuation by polyaniline nanofibers (United States)

    Mehraeen, Shayan; Alkan Gürsel, Selmiye; Papila, Melih; Çakmak Cebeci, Fevzi


    Polyaniline nanofibers have shown promising electrical and electrochemical properties which make them prominent candidates in the development of smart systems employing sensors and actuators. Their electrochemical actuation potential is demonstrated in this study. A trilayer composite actuator based on polyaniline nanofibers was designed and fabricated. Cross-linked polyvinyl alcohol was sandwiched between two polyaniline nanofibrous electrodes as ion-containing electrolyte gel. First, electrochemical behavior of a single electrode was studied, showing reversible redox peak pairs in 1 M HCl using a cyclic voltammetry technique. High aspect ratio polyaniline nanofibers create a porous network which facilitates ion diffusion and thus accelerates redox reactions. Bending displacement of the prepared trilayer actuator was then tested and reported under an AC potential stimulation as low as 0.5 V in a variety of frequencies from 50 to 1000 mHz, both inside 1 M HCl solution and in air. Decay of performance of the composite actuator in air is investigated and it is reported that tip displacement in a solution was stable and repeatable for 1000 s in all selected frequencies.

  2. Evolutionary flight and enabling smart actuator devices (United States)

    Manzo, Justin; Garcia, Ephrahim


    Recent interest in morphing vehicles with multiple, optimized configurations has led to renewed research on biological flight. The flying vertebrates - birds, bats, and pterosaurs - all made or make use of various morphing devices to achieve lift to suit rapidly changing flight demands, including maneuvers as complex as perching and hovering. The first part of this paper will discuss these devices, with a focus on the morphing elements and structural strong suits of each creature. Modern flight correlations to these devices will be discussed and analyzed as valid adaptations of these evolutionary traits. The second part of the paper will focus on the use of active joint structures for use in morphing aircraft devices. Initial work on smart actuator devices focused on NASA Langley's Hyper-Elliptical Cambered Span (HECS) wing platform, which led to development of a discretized spanwise curvature effector. This mechanism uses shape memory alloy (SMA) as the sole morphing actuator, allowing fast rotation with lightweight components at the expense of energy inefficiency. Phase two of morphing actuator development will add an element of active rigidity to the morphing structure, in the form of shape memory polymer (SMP). Employing a composite structure of polymer and alloy, this joint will function as part of a biomimetic morphing actuator system in a more energetically efficient manner. The joint is thermally actuated to allow compliance on demand and rigidity in the nominal configuration. Analytical and experimental joint models are presented, and potential applications on a bat-wing aircraft structure are outlined.

  3. Stretchable Materials for Robust Soft Actuators towards Assistive Wearable Devices (United States)

    Agarwal, Gunjan; Besuchet, Nicolas; Audergon, Basile; Paik, Jamie


    Soft actuators made from elastomeric active materials can find widespread potential implementation in a variety of applications ranging from assistive wearable technologies targeted at biomedical rehabilitation or assistance with activities of daily living, bioinspired and biomimetic systems, to gripping and manipulating fragile objects, and adaptable locomotion. In this manuscript, we propose a novel two-component soft actuator design and design tool that produces actuators targeted towards these applications with enhanced mechanical performance and manufacturability. Our numerical models developed using the finite element method can predict the actuator behavior at large mechanical strains to allow efficient design iterations for system optimization. Based on two distinctive actuator prototypes’ (linear and bending actuators) experimental results that include free displacement and blocked-forces, we have validated the efficacy of the numerical models. The presented extensive investigation of mechanical performance for soft actuators with varying geometric parameters demonstrates the practical application of the design tool, and the robustness of the actuator hardware design, towards diverse soft robotic systems for a wide set of assistive wearable technologies, including replicating the motion of several parts of the human body.

  4. Analysis of Reconfigured Control Loop with a Virtual Actuator

    Directory of Open Access Journals (Sweden)

    Anna Filasova


    Full Text Available Control reconfiguration changes the control structure in response to a fault detected in the plant. This becomes necessary, because a major fault like loss of an actuator breaks the corresponding control loop and therefore renders the whole system inoperable.  An important aim of control reconfiguration is to change the control structure as little as possible, since every change bears the potential of practical problems. The proposed solution is to keep the original controller in the loop and to add an extension called virtual actuator that implements the necessary changes of the control structure. The virtual actuator translates between the signals of the nominal controller and the signal of the faulty plants. This paper is concerned with the analysis of reconfigured loop with a virtual actuator for the system with the faulty actuator. The proposed analysis is illustrated on numerical example.

  5. Optical nano and micro actuator technology

    CERN Document Server

    Knopf, George K


    In Optical Nano and Micro Actuator Technology, leading engineers, material scientists, chemists, physicists, laser scientists, and manufacturing specialists offer an in-depth, wide-ranging look at the fundamental and unique characteristics of light-driven optical actuators. They discuss how light can initiate physical movement and control a variety of mechanisms that perform mechanical work at the micro- and nanoscale. The book begins with the scientific background necessary for understanding light-driven systems, discussing the nature of light and the interaction between light and NEMS/MEMS d

  6. High Performance Piezoelectric Actuated Gimbal (HIERAX)

    Energy Technology Data Exchange (ETDEWEB)

    Charles Tschaggeny; Warren Jones; Eberhard Bamberg


    This paper presents a 3-axis gimbal whose three rotational axes are actuated by a novel drive system: linear piezoelectric motors whose linear output is converted to rotation by using drive disks. Advantages of this technology are: fast response, high accelerations, dither-free actuation and backlash-free positioning. The gimbal was developed to house a laser range finder for the purpose of tracking and guiding unmanned aerial vehicles during landing maneuvers. The tilt axis was built and the test results indicate excellent performance that meets design specifications.

  7. Distributed shell control with a new multi-DOF photostrictive actuator design (United States)

    Yue, H. H.; Sun, G. L.; Deng, Z. Q.; Tzou, H. S.


    With the photovoltaic effect and the converse piezoelectric effect, the lanthanum-modified lead zirconate titanate (PLZT) actuator can transform the narrow-band photonic energy to mechanical strain/stress—the photodeformation effect. This photodeformation process can be further used for non-contact precision actuation and control in various structural, biomedical and electromechanical systems. Although there are a number of design configurations of distributed actuators, e.g., segmentation and shaping, been investigated over the years, this study is to explore a new actuator configuration spatially bonded on the surface of shell structures to enhance the spatial modal controllability. A mathematical model of a new multiple degree-of-freedom (multi-DOF) photostrictive actuator configuration is presented first, followed by the photostrictive/shell coupling equations of a cylindrical shell structure laminated with the newly proposed multi-DOF distributed actuator. Distributed microscopic photostrictive actuation and its contributing components of a one-piece actuator and the multi-DOF actuator are evaluated in the modal domain. Effects of shell's curvature and actuator's size are also evaluated. Parametric analyses suggest that the new multi-DOF distributed actuator, indeed, provides better performance and control effect to shell actuation and control. This multi-DOF configuration can be further applied to actuation and control of various shell and non-shell structures.

  8. Selecting Actuator Configuration for a Benson Boiler

    DEFF Research Database (Denmark)

    Kragelund, Martin Nygaard; Leth, John-Josef; Wisniewski, Rafal


    with particular focus on a boiler in a power plant operated by DONG Energy - a Danish energy supplier. The problem has been reformulated using mathematic notions from economics. The selection of actuator configuration has been limited to the fuel system which in the considered plant consists of three different...

  9. Influencing the naval mine actuation location

    NARCIS (Netherlands)

    Veldhoven, J. van; Beckers, A.L.D.


    During a naval mine sweeping operation, there is a risk of damage to the sweeping gear due to mine detonations. To reduce this risk, we mention five different methods to influence the actuation location of naval mines relative to a sweeping system. Three of these are discussed in more detail, using

  10. Math Machines: Using Actuators in Physics Classes (United States)

    Thomas, Frederick J.; Chaney, Robert A.; Gruesbeck, Marta


    Probeware (sensors combined with data-analysis software) is a well-established part of physics education. In engineering and technology, sensors are frequently paired with actuators--motors, heaters, buzzers, valves, color displays, medical dosing systems, and other devices that are activated by electrical signals to produce intentional physical…

  11. Active Polymer Gel Actuators

    Directory of Open Access Journals (Sweden)

    Shuji Hashimoto


    Full Text Available Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of heart muscles. Here we show a novel biomimetic gel actuator that can walk spontaneously with a wormlike motion without switching of external stimuli. The self-oscillating motion is produced by dissipating chemical energy of oscillating reaction. Although the gel is completely composed of synthetic polymer, it shows autonomous motion as if it were alive.

  12. Microfabricated therapeutic actuators (United States)

    Lee, Abraham P.; Northrup, M. Allen; Ciarlo, Dino R.; Krulevitch, Peter A.; Benett, William J.


    Microfabricated therapeutic actuators are fabricated using a shape memory polymer (SMP), a polyurethane-based material that undergoes a phase transformation at a specified temperature (Tg). At a temperature above temperature Tg material is soft and can be easily reshaped into another configuration. As the temperature is lowered below temperature Tg the new shape is fixed and locked in as long as the material stays below temperature Tg. Upon reheating the material to a temperature above Tg, the material will return to its original shape. By the use of such SMP material, SMP microtubing can be used as a release actuator for the delivery of embolic coils through catheters into aneurysms, for example. The microtubing can be manufactured in various sizes and the phase change temperature Tg is determinate for an intended temperature target and intended use.

  13. Dissolution actuated sample container (United States)

    Nance, Thomas A.; McCoy, Frank T.


    A sample collection vial and process of using a vial is provided. The sample collection vial has an opening secured by a dissolvable plug. When dissolved, liquids may enter into the interior of the collection vial passing along one or more edges of a dissolvable blocking member. As the blocking member is dissolved, a spring actuated closure is directed towards the opening of the vial which, when engaged, secures the vial contents against loss or contamination.

  14. Cylindrical Piezoelectric Fiber Composite Actuators (United States)

    Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.


    The use of piezoelectric devices has become widespread since Pierre and Jacques Curie discovered the piezoelectric effect in 1880. Examples of current applications of piezoelectric devices include ultrasonic transducers, micro-positioning devices, buzzers, strain sensors, and clocks. The invention of such lightweight, relatively inexpensive piezoceramic-fiber-composite actuators as macro fiber composite (MFC) actuators has made it possible to obtain strains and displacements greater than those that could be generated by prior actuators based on monolithic piezoceramic sheet materials. MFC actuators are flat, flexible actuators designed for bonding to structures to apply or detect strains. Bonding multiple layers of MFC actuators together could increase force capability, but not strain or displacement capability. Cylindrical piezoelectric fiber composite (CPFC) actuators have been invented as alternatives to MFC actuators for applications in which greater forces and/or strains or displacements may be required. In essence, a CPFC actuator is an MFC or other piezoceramic fiber composite actuator fabricated in a cylindrical instead of its conventional flat shape. Cylindrical is used here in the general sense, encompassing shapes that can have circular, elliptical, rectangular or other cross-sectional shapes in the planes perpendicular to their longitudinal axes.

  15. Mechanisms and actuators for rotorcraft blade morphing (United States)

    Vocke, Robert D., III

    The idea of improved fight performance through changes in the control surfaces dates back to the advent of aviation with the Wright brothers' pioneering work on "wing warping," but it was not until the recent progress in material and actuator development that such control surfaces seemed practical for modern aircraft. This has opened the door to a new class of aircraft that have the ability to change shape or morph, which are being investigated due to the potential to have a single platform serve multiple mission objectives, as well as improve performance characteristics. While the majority of existing research for morphing aircraft has focused on fixedwing aircraft, rotary-wing aircraft have begun to receive more attention. The purpose of this body of work is to investigate the current state of morphing actuation technology for rotorcraft and improve upon it. Specifically, this work looks at two types of morphing: Pneumatic Artificial Muscle (PAM) actuated trailing edge flaps and conformal variable diameter morphing. First, active camber changes through the use of PAM powered trailing edge flaps were investigated due to the potential for reductions in power requirements and vibration/noise levels. A PAM based antagonistic actuation system was developed utilizing a novel combination of mechanism geometry and PAM bias contraction optimization to overcome the natural extension stiffening characteristics of PAMs. In open-loop bench-top testing against a "worst-case" constant torsional loading, the system demonstrated actuation authority suitable for both primary control and vibration/noise reduction. Additionally, closed-loop test data indicated that the system was capable of tracking complex waveforms consistent with those needed for rotorcraft control. This system demonstrated performance on-par with the state of the art pneumatic trailing edge flap actuators, yet with a much smaller footprint and impact on the rotor-blade. The second morphing system developed in

  16. Microelectromechanical (MEM) thermal actuator (United States)

    Garcia, Ernest J [Albuquerque, NM; Fulcher, Clay W. G. [Sandia Park, NM


    Microelectromechanical (MEM) buckling beam thermal actuators are disclosed wherein the buckling direction of a beam is constrained to a desired direction of actuation, which can be in-plane or out-of-plane with respect to a support substrate. The actuators comprise as-fabricated, linear beams of uniform cross section supported above the substrate by supports which rigidly attach a beam to the substrate. The beams can be heated by methods including the passage of an electrical current through them. The buckling direction of an initially straight beam upon heating and expansion is controlled by incorporating one or more directional constraints attached to the substrate and proximal to the mid-point of the beam. In the event that the beam initially buckles in an undesired direction, deformation of the beam induced by contact with a directional constraint generates an opposing force to re-direct the buckling beam into the desired direction. The displacement and force generated by the movement of the buckling beam can be harnessed to perform useful work, such as closing contacts in an electrical switch.

  17. Composite thermal micro-actuator array for tactile displays (United States)

    Enikov, Eniko T.; Lazarov, Kalin V.


    Tactile perception of complex symbols through tactile stimulation is an exciting application of a phenomenon known as tactile illusion (TI). Sensation of motion on the skin can be produced by a limited number of discrete mechanical actuators applying light pressure over the skin. This phenomenon can thus be used as a neurophysiological testing tool to determine central and peripheral nervous system injury as well as providing an additional human-machine communication channel. This paper describes the development of a 4 x 5 actuator array of individual vibrating pixels for fingertip tactile communication. The array is approximately one square centimeter and utilizes novel micro-clutch MEMS technology. The individual pixels are turned ON and OFF by pairs of microscopic composite thermal actuators, while the main vibration is generated by a vibrating piezo-electric plate. The physiological parameters required for inducing tactile illusion are described. The fabrication sequence for the thermal micro-actuators along with actuation results are also presented.

  18. Nonlinear Tracking Control of a Conductive Supercoiled Polymer Actuator. (United States)

    Luong, Tuan Anh; Cho, Kyeong Ho; Song, Min Geun; Koo, Ja Choon; Choi, Hyouk Ryeol; Moon, Hyungpil


    Artificial muscle actuators made from commercial nylon fishing lines have been recently introduced and shown as a new type of actuator with high performance. However, the actuators also exhibit significant nonlinearities, which make them difficult to control, especially in precise trajectory-tracking applications. In this article, we present a nonlinear mathematical model of a conductive supercoiled polymer (SCP) actuator driven by Joule heating for model-based feedback controls. Our efforts include modeling of the hysteresis behavior of the actuator. Based on nonlinear modeling, we design a sliding mode controller for SCP actuator-driven manipulators. The system with proposed control law is proven to be asymptotically stable using the Lyapunov theory. The control performance of the proposed method is evaluated experimentally and compared with that of a proportional-integral-derivative (PID) controller through one-degree-of-freedom SCP actuator-driven manipulators. Experimental results show that the proposed controller's performance is superior to that of a PID controller, such as the tracking errors are nearly 10 times smaller compared with those of a PID controller, and it is more robust to external disturbances such as sensor noise and actuator modeling error.

  19. Development of a soft untethered robot using artificial muscle actuators (United States)

    Cao, Jiawei; Qin, Lei; Lee, Heow Pueh; Zhu, Jian


    Soft robots have attracted much interest recently, due to their potential capability to work effectively in unstructured environment. Soft actuators are key components in soft robots. Dielectric elastomer actuators are one class of soft actuators, which can deform in response to voltage. Dielectric elastomer actuators exhibit interesting attributes including large voltage-induced deformation and high energy density. These attributes make dielectric elastomer actuators capable of functioning as artificial muscles for soft robots. It is significant to develop untethered robots, since connecting the cables to external power sources greatly limits the robots' functionalities, especially autonomous movements. In this paper we develop a soft untethered robot based on dielectric elastomer actuators. This robot mainly consists of a deformable robotic body and two paper-based feet. The robotic body is essentially a dielectric elastomer actuator, which can expand or shrink at voltage on or off. In addition, the two feet can achieve adhesion or detachment based on the mechanism of electroadhesion. In general, the entire robotic system can be controlled by electricity or voltage. By optimizing the mechanical design of the robot (the size and weight of electric circuits), we put all these components (such as batteries, voltage amplifiers, control circuits, etc.) onto the robotic feet, and the robot is capable of realizing autonomous movements. Experiments are conducted to study the robot's locomotion. Finite element method is employed to interpret the deformation of dielectric elastomer actuators, and the simulations are qualitatively consistent with the experimental observations.

  20. Integrated sensing and actuation of dielectric elastomer actuator (United States)

    Ye, Zhihang; Chen, Zheng


    Dielectric elastomer (DE) is a type of soft actuating material, the shape of which can be changed under electrical voltage stimuli. DE materials have great potential in applications involving energy harvesters, micro-manipulators, and adaptive optics. In this paper, a stripe DE actuator with integrated sensing and actuation is designed and fabricated, and characterized through several experiments. Considering the actuator's capacitor-like structure and its deform mechanism, detecting the actuator's displacement through the actuator's circuit feature is a potential approach. A self-sensing scheme that adds a high frequency probing signal into actuation signal is developed. A fast Fourier transform (FFT) algorithm is used to extract the magnitude change of the probing signal, and a non-linear fitting method and artificial neural network (ANN) approach are utilized to reflect the relationship between the probing signal and the actuator's displacement. Experimental results showed this structure has capability of performing self-sensing and actuation, simultaneously. With an enhanced ANN, the self-sensing scheme can achieve 2.5% accuracy.

  1. Actuation crosstalk in free-falling systems: Torsion pendulum results for the engineering model of the LISA pathfinder gravitational reference sensor (United States)

    Bassan, M.; Cavalleri, A.; De Laurentis, M.; De Marchi, F.; De Rosa, R.; Di Fiore, L.; Dolesi, R.; Finetti, N.; Garufi, F.; Grado, A.; Hueller, M.; Marconi, L.; Milano, L.; Minenkov, Y.; Pucacco, G.; Stanga, R.; Vetrugno, D.; Visco, M.; Vitale, S.; Weber, W. J.


    In this paper we report on measurements on actuation crosstalk, relevant to the gravitational reference sensors for LISA Pathfinder and LISA. In these sensors, a Test Mass (TM) falls freely within a system of electrodes used for readout and control. These measurements were carried out on ground with a double torsion pendulum that allowed us to estimate both the torque injected into the sensor when a control force is applied and, conversely, the force leaking into the translational degree of freedom due to the applied torque.The values measured on our apparatus (the engineering model of the LISA Pathfinder sensor) agree to within 0.2% (over a maximum measured crosstalk of 1%) with predictions of a mathematical model when measuring force to torque crosstalk, while it is somewhat larger than expected (up to 3.5%) when measuring torque to force crosstalk. However, the values in the relevant range, i.e. when the TM is well centered ( ± 10 μm) in the sensor, remain smaller than 0.2%, satisfying the LISA Pathfinder requirements.

  2. Discrete Event-Triggered Robust Fault-Tolerant Control for Nonlinear Networked Control Systems with α-Safety Degree and Actuator Saturation

    Directory of Open Access Journals (Sweden)

    Yajie Li


    Full Text Available This paper deals with the discrete event-triggered robust fault-tolerant control problem for uncertain nonlinear networked control systems (NNCSs with α-safety degree. A discrete event-triggered communication scheme (DETCS is initially proposed, and a closed-loop fault model is subsequently established for NNCSs with actuator saturation under the DETCS. Based on an appropriately constructed delay-dependent Lyapunov–Krasovskii function, sufficient conditions are derived to guarantee the asymptotic stability of NNCSs under two different event-triggered conditions and are established as the contractively invariant sets of fault tolerance with α-safety degree. Furthermore, codesign methods between the robust fault-tolerant controller and event-triggered weight matrix are also proposed in terms of linear matrix inequality. The simulation shows that the resultant closed-loop fault NNCSs possesses a high safety margin, and an improved dynamic performance, as well as a reduced communication load. A comparative analysis of the two event-triggered conditions is discussed in the experiment section.

  3. Telescoping cylindrical piezoelectric fiber composite actuator assemblies (United States)

    Allison, Sidney G. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Christopher L. (Inventor); Fox Chattin, legal representative, Melanie L. (Inventor)


    A telescoping actuator assembly includes a plurality of cylindrical actuators in a concentric arrangement. Each cylindrical actuator is at least one piezoelectric fiber composite actuator having a plurality of piezoelectric fibers extending parallel to one another and to the concentric arrangement's longitudinal axis. Each cylindrical actuator is coupled to concentrically-adjacent ones of the cylindrical actuators such that the plurality of cylindrical actuators can experience telescopic movement. An electrical energy source coupled to the cylindrical actuators applies actuation energy thereto to generate the telescopic movement.

  4. A small biomimetic quadruped robot driven by multistacked dielectric elastomer actuators (United States)

    Nguyen, Canh Toan; Phung, Hoa; Dat Nguyen, Tien; Lee, Choonghan; Kim, Uikyum; Lee, Donghyouk; Moon, Hyungpil; Koo, Jachoon; Nam, Jae-do; Ryeol Choi, Hyouk


    A kind of dielectric elastomer (DE) material, called ‘synthetic elastomer’, has been developed based on acrylonitrile butadiene rubber (NBR) to be used as a dielectric elastomer actuator (DEA). By stacking single layers of synthetic elastomer, a linear actuator, called a multistacked actuator, is produced, and used by mechatronic and robotic systems to generate linear motion. In this paper, we demonstrate the application of the multistacked dielectric elastomer actuator in a biomimetic legged robot. A miniature robot driven by a biomimetic actuation system with four 2-DOF (two-degree-of-freedom) legged mechanisms is realized. Based on the experimental results, we evaluate the performance of the proposed robot and validate the feasibility of the multistacked actuator in a locomotion system as a replacement for conventional actuators.

  5. Adaptive Fuzzy Output-Constrained Fault-Tolerant Control of Nonlinear Stochastic Large-Scale Systems With Actuator Faults. (United States)

    Li, Yongming; Ma, Zhiyao; Tong, Shaocheng


    The problem of adaptive fuzzy output-constrained tracking fault-tolerant control (FTC) is investigated for the large-scale stochastic nonlinear systems of pure-feedback form. The nonlinear systems considered in this paper possess the unstructured uncertainties, unknown interconnected terms and unknown nonaffine nonlinear faults. The fuzzy logic systems are employed to identify the unknown lumped nonlinear functions so that the problems of structured uncertainties can be solved. An adaptive fuzzy state observer is designed to solve the nonmeasurable state problem. By combining the barrier Lyapunov function theory, adaptive decentralized and stochastic control principles, a novel fuzzy adaptive output-constrained FTC approach is constructed. All the signals in the closed-loop system are proved to be bounded in probability and the system outputs are constrained in a given compact set. Finally, the applicability of the proposed controller is well carried out by a simulation example.

  6. Design, dynamics and control of an Adaptive Singularity-Free Control Moment Gyroscope actuator for microspacecraft Attitude Determination and Control System (United States)

    Viswanathan, Sasi Prabhakaran

    how they lead to CMG singularities, are described. General ideas on control of the angular momentum of the spacecraft using changes in the momentum variables of a finite number of ASCMGs, are provided. Control schemes for agile and precise attitude maneuvers using ASCMG cluster in the absence of external torques and when the total angular momentum of the spacecraft is zero, is presented for both constant speed and variable speed modes. A Geometric Variational Integrator (GVI) that preserves the geometry of the state space and the conserved norm of the total angular momentum is constructed for numerical simulation and microcontroller implementation of the control scheme. The GVI is obtained by discretizing the Lagrangian of the rnultibody systems, in which the rigid body attitude is globally represented on the Lie group of rigid body rotations. Hardware and software architecture of a novel spacecraft Attitude Determination and Control System (ADCS) based on commercial smartphones and a bare minimum hardware prototype of an ASCMG using low cost COTS components is also described. A lightweight, dynamics model-free Variational Attitude Estimator (VAE) suitable for smartphone implementation is employed for attitude determination and the attitude control is performed by ASCMG actuators. The VAE scheme presented here is implemented and validated onboard an Unmanned Aerial Vehicle (UAV) platform and the real time performance is analyzed. On-board sensing, data acquisition, data uplink/downlink, state estimation and real-time feedback control objectives can be performed using this novel spacecraft ADCS. The mechatronics realization of the attitude determination through variational attitude estimation scheme and control implementation using ASCMG actuators are presented here. Experimental results of the attitude estimation (filtering) scheme using smartphone sensors as an Inertial Measurement Unit (IMU) on the Hardware In the Loop (HIL) simulator testbed are given. These

  7. Biomimetic jellyfish-inspired underwater vehicle actuated by ionic polymer metal composite actuators (United States)

    Najem, Joseph; Sarles, Stephen A.; Akle, Barbar; Leo, Donald J.


    This paper presents the design, fabrication, and characterization of a biomimetic jellyfish robot that uses ionic polymer metal composites (IPMCs) as flexible actuators for propulsion. The shape and swimming style of this underwater vehicle are based on the Aequorea victoria jellyfish, which has an average swimming speed of 20 mm s-1 and which is known for its high swimming efficiency. The Aequorea victoria is chosen as a model system because both its bell morphology and kinematic properties match the mechanical properties of IPMC actuators. This medusa is characterized by its low swimming frequency, small bell deformation during the contraction phase, and high Froude efficiency. The critical components of the robot include the flexible bell that provides the overall shape and dimensions of the jellyfish, a central hub and a stage used to provide electrical connections and mechanical support to the actuators, eight distinct spars meant to keep the upper part of the bell stationary, and flexible IPMC actuators that extend radially from the central stage. The bell is fabricated from a commercially available heat-shrinkable polymer film to provide increased shape-holding ability and reduced weight. The IPMC actuators constructed for this study demonstrated peak-to-peak strains of ˜0.7% in water across a frequency range of 0.1-1.0 Hz. By tailoring the applied voltage waveform and the flexibility of the bell, the completed robotic jellyfish with four actuators swam at an average speed 0.77 mm s-1 and consumed 0.7 W. When eight actuators were used the average speed increased to 1.5 mm s-1 with a power consumption of 1.14 W.

  8. Actuator technology and market outlook: where does the actuator move

    Directory of Open Access Journals (Sweden)

    Aleksanin Sergei Andreevich


    There are made conclusions about the "migration" of demand from hydraulic and pneumatic solutions to electromechanical actuators in the aerospace and manufacturing industries. Identify advantages of electromechanics over more traditional actuators in terms of energy efficiency and reliability. Also identify the most promising areas of the drive technological development.

  9. Piezoelectric actuated gimbal (United States)

    Tschaggeny, Charles W [Woods Cross, UT; Jones, Warren F [Idaho Falls, ID; Bamberg, Eberhard [Salt Lake City, UT


    A gimbal is described and which includes a fixed base member defining an axis of rotation; a second member concentrically oriented relative to the axis of rotation; a linear actuator oriented in immediate, adjoining force transmitting relation relative to the base member or to the second member, and which applies force along a linear axis which is tangential to the axis of rotation so as to cause the second member to rotate coaxially relative to the fixed base member; and an object of interest mounted to the second member such that the object of interest is selectively moved relative to the base member about the axis of rotation.

  10. Robotic Arm Actuated by Electroactie Polymers (United States)

    Bar-Cohen, Y.; Xue, T.; Shaninpoor, M.; Simpson, J. O.; Smith, J.


    Actuators are used for many planetary and space applications. To meet the NASA goal to reduce the actuators size, mass, cost and power consumption, electroactie polymers (EAP) are being developed to induce large bending and longitudinal actuation strains.

  11. Electrostatic microvalves utilizing conductive nanoparticles for improved speed, lower power, and higher force actuation.

    Energy Technology Data Exchange (ETDEWEB)

    Ten Eyck, Gregory A.; Branson, Eric D.; Kenis, Paul J. A. (University of Illinois, Champaign Urbana); Desai, Amit (University of Illinois, Champaign Urbana); Schudel, Ben (University of Illinois, Champaign Urbana); Givler, Richard C.; Tice, Josh (University of Illinois, Champaign Urbana); Collord, Andrew; Apblett, Christopher Alan; Cook, Adam W.


    We have designed and built electrostatically actuated microvalves compatible with integration into a PDMS based microfluidic system. The key innovation for electrostatic actuation was the incorporation of carbon nanotubes into the PDMS valve membrane, allowing for electrostatic charging of the PDMS layer and subsequent discharging, while still allowing for significant distention of the valveseat for low voltage control of the system. Nanoparticles were applied to semi-cured PDMS using a stamp transfer method, and then cured fully to make the valve seats. DC actuation in air of these valves yielded operational voltages as low as 15V, by using a supporting structure above the valve seat that allowed sufficient restoring forces to be applied while not enhancing actuation forces to raise the valve actuation potential. Both actuate to open and actuate to close valves have been demonstrated, and integrated into a microfluidic platform, and demonstrated fluidic control using electrostatic valves.

  12. MSM actuators: design rules and control strategies

    Energy Technology Data Exchange (ETDEWEB)

    Holz, Benedikt; Janocha, Hartmut [Laboratory of Process Automation (LPA), Saarland University, Saarbruecken (Germany); Riccardi, Leonardo; Naso, David [Department of Electronics and Electrical Science (DEE), Politecnico di Bari (Italy)


    Magnetic shape memory (MSM) alloys are comparatively new active materials which can be used for several industrial applications, ranging from precise positioning systems to advanced robotics. Beyond the material research, which deals with the basic thermo-magneto-mechanical properties of the crystals, the design as well as the control of the actuators displacement is an essential challenge. This paper addresses those two topics, trying to give to the reader a useful overview of existing results, but also presents new ideas. First, it introduces and discusses in details some possible designs, with a special emphasis on innovative actuator design concepts which are able to exploit the particular potentialities of MSM elements. The second focus of the paper is on the problem of designing a controller, i.e., an algorithm that allows to obtain a required performance from the actuator. The proposed control strategies try to take into account two main characteristics of MSM elements: the hysteresis and the temperature dependence. The effectiveness of the strategies is emphasized by experimental results performed on a commercially available MSM actuator demonstrator. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. A Sliding Mode LCO Regulation Strategy for Dual-Parallel Underactuated UAV Systems Using Synthetic Jet Actuators

    Directory of Open Access Journals (Sweden)

    N. Ramos-Pedroza


    careful algebraic manipulation in the regulation error system development, along with innovative design of the sliding surface. A detailed model of the UAV LCO dynamics is utilized, and a rigorous analysis is provided to prove asymptotic regulation of the pitching and plunging displacements. Numerical simulation results are provided to demonstrate the performance of the control law.

  14. Application of AI techniques to a voice-actuated computer system for reconstructing and displaying magnetic resonance imaging data (United States)

    Sherley, Patrick L.; Pujol, Alfonso, Jr.; Meadow, John S.


    To provide a means of rendering complex computer architectures languages and input/output modalities transparent to experienced and inexperienced users research is being conducted to develop a voice driven/voice response computer graphics imaging system. The system will be used for reconstructing and displaying computed tomography and magnetic resonance imaging scan data. In conjunction with this study an artificial intelligence (Al) control strategy was developed to interface the voice components and support software to the computer graphics functions implemented on the Sun Microsystems 4/280 color graphics workstation. Based on generated text and converted renditions of verbal utterances by the user the Al control strategy determines the user''s intent and develops and validates a plan. The program type and parameters within the plan are used as input to the graphics system for reconstructing and displaying medical image data corresponding to that perceived intent. If the plan is not valid the control strategy queries the user for additional information. The control strategy operates in a conversation mode and vocally provides system status reports. A detailed examination of the various AT techniques is presented with major emphasis being placed on their specific roles within the total control strategy structure. 1.

  15. A centrifugally actuated point-of-care testing system for the surface acoustic wave immunosensing of cardiac troponin I. (United States)

    Lee, Woochang; Jung, Jaeyeon; Hahn, Young Ki; Kim, Sang Kyu; Lee, Yeolho; Lee, Joonhyung; Lee, Tae-Han; Park, Jin-Young; Seo, Hyejung; Lee, Jung Nam; Oh, Jin Ho; Choi, Youn-Suk; Lee, Soo Suk


    A fully automated point-of-care testing (POCT) system with a surface acoustic wave (SAW) immunosensor was developed for rapid and sensitive detection of cardiac troponin I (cTnI) in body fluid (plasma and whole blood). The assay, based on gold nanoparticle sandwich immunoassay and subsequent gold staining, was performed on the SAW immunosensor packaged inside a disposable microfluidic cartridge. The entire fluidic process, including plasma separation, reagent transport, metering, and mixing, was carried out by controlling the centrifugal force acting on the rotating cartridge and laser-irradiated ferrowax microvalves. On investigation of sensor response to various cTnI concentrations, the system exhibited a high performance with a detection limit of 6.7 pg mL(-1), and the coefficient of variation was less than 10% over the entire test range (10 pg mL(-1) to 25 ng mL(-1)). On comparing this POCT system with a clinically utilized system in a physical laboratory (Centaur® XP; Siemens), a correlation coefficient of 0.998 was found, validating the diagnostic capability of the SAW immunosensor.

  16. Biomimetic photo-actuation: sensing, control and actuation in sun-tracking plants. (United States)

    Dicker, M P M; Rossiter, J M; Bond, I P; Weaver, P M


    Although the actuation mechanisms that drive plant movement have been investigated from a biomimetic perspective, few studies have looked at the wider sensing and control systems that regulate this motion. This paper examines photo-actuation-actuation induced by, and controlled with light-through a review of the sun-tracking functions of the Cornish Mallow. The sun-tracking movement of the Cornish Mallow leaf results from an extraordinarily complex-yet extremely elegant-process of signal perception, generation, filtering and control. Inspired by this process, a concept for a simplified biomimetic analogue of this leaf is proposed: a multifunctional structure employing chemical sensing, signal transmission, and control of composite hydrogel actuators. We present this multifunctional structure, and show that the success of the concept will require improved selection of materials and structural design. This device has application in the solar-tracking of photovoltaic panels for increased energy yield. More broadly it is envisaged that the concept of chemical sensing and control can be expanded beyond photo-actuation to many other stimuli, resulting in new classes of robust solid-state devices.

  17. Electromagnetic actuation in MEMS switches

    DEFF Research Database (Denmark)

    Oliveira Hansen, Roana Melina de; Mátéfi-Tempfli, Mária; Chemnitz, Steffen

    . Electromagnetic actuation is a very promising approach to operate such MEMS and Power MEMS devices, due to the long range, reproducible and strong forces generated by this method, among other advantages. However, the use of electromagnetic actuation in such devices requires the use of thick magnetic films, which...

  18. Novel ionic polymeric hydraulic actuators (United States)

    Shahinpoor, Mohsen; Kim, Kwang J.


    It is now well recognized that a strip of ionic polymer- metal composite (IPMC) exhibits a spontaneous bending capability under the influence of an electric potential. A key observation is the appearance and disappearance of water on the expansion and contraction surfaces of the strip, respectively. Such water appearing/disappearing activities occur near the permeable metal electrodes. The imposition of en elctric field causes the mobile cations that are conjugated to the polymeric anions to undergo electrophoretic dynamic migration that can result in local deformation of the material. Such an electrophoretic behavior of the IPMC causes the water to leak out of the permeable electroded boundary so as to lower the actuation performance. This situation is similar to a leaking hydraulic actuator (hydraulic jack), which has the highest force density notwithstanding the compressor unit weight. Herein, a new category of actuators as ionic polymeric hydraulic actuators (IPHA's) is defined. The IPMC is a good example of such ionic polymeric hydraulic actuators. The advantage of ionic polymeric hydraulic actuators is their potential to generate substantially high force densities, theoretically better than current hydraulic actuators. Based upon this ionic polymer hydraulic actuator concept, a certain manufacturing technique was developed to increase the force density of the conventional IPMC's by a factor of two (100% improvement in force). This technology and associated experimental results are presented in this paper.

  19. Controlling flexible structures with second order actuator dynamics (United States)

    Inman, Daniel J.; Umland, Jeffrey W.; Bellos, John


    The control of flexible structures for those systems with actuators that are modeled by second order dynamics is examined. Two modeling approaches are investigated. First a stability and performance analysis is performed using a low order finite dimensional model of the structure. Secondly, a continuum model of the flexible structure to be controlled, coupled with lumped parameter second order dynamic models of the actuators performing the control is used. This model is appropriate in the modeling of the control of a flexible panel by proof-mass actuators as well as other beam, plate and shell like structural numbers. The model is verified with experimental measurements.

  20. Research on giant magnetostrictive micro-displacement actuator with self-adaptive control algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Wang Lei; Tan, J B; Liu, Y T [Institute of Ultra-Precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin 150001 (China)


    Giant magnetostrictive micro-displacement actuator has some unique characteristics, such as big output torque and high precision localization which can be in the nanometer scale. Because the relation between input magnetic field and output strain of giant magnetostrictive micro-displacement actuator exhibits hysteresis and eddy flow, the actuator has to be controlled and used in low input frequency mode or in static mode. When the actuator is controlled with a high input frequency (above 100 Hz), the output strain will exhibit strong nonlinearity. This paper found hysteresis and nonlinearity dynamic transfer function of the actuator based on Jiles-Atherton hysteresis model. The output strain of Jiles-Atherton hystersis model can reflect real output of actuator corresponding to the real input magnetic field, and this has been verified by experiment. Against the nonlinearity generated by hysteresis and eddy flow in this paper, the output strain of actuator is used for feedback to control system, and the control system adopted self-adaptive control algorithm, the ideal input and output model of actuator is used for a reference model and a hysteresis transfer function for the actuator real model. Through experiment, it has been verified that this algorithm can improve the dynamic frequency of the giant magnetostrictive micro-displacement actuator and guarantee high precision localization and linearity between the input magnetic field and output strain of the actuator at the same time.

  1. Fault Diagnosis for Actuators in a Class of Nonlinear Systems Based on an Adaptive Fault Detection Observer

    Directory of Open Access Journals (Sweden)

    Runxia Guo


    Full Text Available The problem of actuators’ fault diagnosis is pursued for a class of nonlinear control systems that are affected by bounded measurement noise and external disturbances. A novel fault diagnosis algorithm has been proposed by combining the idea of adaptive control theory and the approach of fault detection observer. The asymptotical stability of the fault detection observer is guaranteed by setting the adaptive adjusting law of the unknown fault vector. A theoretically rigorous proof of asymptotical stability has been given. Under the condition that random measurement noise generated by the sensors of control systems and external disturbances exist simultaneously, the designed fault diagnosis algorithm is able to successfully give specific estimated values of state variables and failures rather than just giving a simple fault warning. Moreover, the proposed algorithm is very simple and concise and is easy to be applied to practical engineering. Numerical experiments are carried out to evaluate the performance of the fault diagnosis algorithm. Experimental results show that the proposed diagnostic strategy has a satisfactory estimation effect.

  2. Satellite Attitude Control Using Only Electromagnetic Actuation

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    of the work was on the class of periodic systems reflecting orbital motion of the satellite. In addition to a theoretical treatment, the thesis contains a large portion of application considerations. The controllers developed were implemented for the Danish Ørsted satellite. The control concept considered......The primary purpose of this work was to develop control laws for three axis stabilization of a magnetic actuated satellite. This was achieved by a combination of linear and nonlinear system theory. In order to reach this goal new theoretical results were produced in both fields. The focus...... was that interaction between the Earth's magnetic field and a magnetic field generated by a set of coils in the satellite can be used for actuation. Magnetic torquing was found attractive for generation of control torques on small satellites, since magnetic control systems are relatively lightweight, require low power...

  3. Failure of cargo aileron’s actuator

    Directory of Open Access Journals (Sweden)

    G. Zucca


    Full Text Available During a ferry flight, in a standard operation condition and at cruising level, a military cargo experienced a double hydraulic system failure due to a structural damage of the dual booster actuator. The booster actuator is the main component in mechanism of aileron’s deflection. The crew was able to arrange an emergency landing thanks to the spare oil onboard: load specialists refilled the hydraulic reservoirs. Due to safety concerns and in order to prevent the possibility of other similar incidents, a technical investigation took place. The study aimed to carry out the analysis of root causes of the actuator failure. The Booster actuator is composed mainly by the piston rod and its aluminum external case (AA7049. The assembly has two bronze caps on both ends. These are fixed in position by means of two retainers. At one end of the actuator case is placed a trunnion: a cylindrical protrusion used as a pivoting point on the aircraft. The fracture was located at one end of the case, on the trunnion side, in correspondence to the cap and over the retainer. One of the two fracture surfaces was found separated to the case and with the cap entangled inside. The fracture surfaces of the external case indicated fatigue crack growth followed by ductile separation. The failure analysis was performed by means of optical, metallographic, digital and electronic microscopy. The collected evidences showed a multiple initiation fracture mechanism. Moreover, 3D scanner reconstruction and numerical simulation demonstrated that dimensional non conformances and thermal loads caused an abnormal stress concentration. Stress concentration was located along the case assy outer surface where the fatigue crack originated. The progressive rupture mechanism grew under cyclical axial load due to the normal operations. Recommendations were issued in order to improve dimensional controls and assembly procedures during production and overhaul activities.

  4. The 3DBiopsy Prostate Biopsy System: Preclinical Investigation of a Needle, Actuator, and Specimen Collection Device Allowing Sampling of Individualized Prostate Lengths Between 20 and 60 mm. (United States)

    Stone, Nelson N; Mouraviev, Vladimir; Schechter, David; Lucia, M Scott; Smith, Elizabeth E; Arangua, Paul; Hoenemeyer, John; Rosa, Jim; Bawa, Rajan; Crawford, E David


    To increase the likelihood of detecting anterior cancers within the prostate and provide a specimen that spans the length of the gland. Newly designed 17- and 15-gauge (G) biopsy needles, a variable actuator, and an integrated pathology system intended for the longer cores were developed and tested for this purpose. Testing was performed comparing 2 common cannula tip grinds, a Vet-point (sharp tip) and a Menghini-point (atraumatic tip), and were tested against 18-G Bard Monopty in porcine kidney. A variable actuator was developed to fire the needle 20-60 mm and tested in cadaver prostates. The aggregate firings for 3 different shot lengths comparing the Vet- with the Menghini-tip cannulas demonstrated 91% vs 85.2% fill (length of specimen/length of core bed, P = .007). A 15-G trocar needle with the Vet-tip cannula also had the best performance, with an aggregate standard deviation of 6.4% across 3 firing ranges and a minimum to maximum specimen length of 81%-105% of potential fill. Cadaver testing with the Vet-tip needles in the actuator for the transrectal (17-G) and transperineal (15-G) biopsies demonstrated mean fills of 93.3% and 76.5%, respectively. The new transrectal ultrasound needle obtained a 2-fold increase in specimen length over the standard Bard device (P enhance focal therapy planning. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Dielectric elastomer actuators for octopus inspired suction cups. (United States)

    Follador, M; Tramacere, F; Mazzolai, B


    Suction cups are often found in nature as attachment strategy in water. Nevertheless, the application of the artificial counterpart is limited by the dimension of the actuators and their usability in wet conditions. A novel design for the development of a suction cup inspired by octopus suckers is presented. The main focus of this research was on the modelling and characterization of the actuation unit, and a first prototype of the suction cup was realized as a proof of concept. The actuation of the suction cup is based on dielectric elastomer actuators. The presented device works in a wet environment, has an integrated actuation system, and is soft. The dimensions of the artificial suction cups are comparable to proximal octopus suckers, and the attachment mechanism is similar to the biological counterpart. The design approach proposed for the actuator allows the definition of the parameters for its development and for obtaining a desired pressure in water. The fabricated actuator is able to produce up to 6 kPa of pressure in water, reaching the maximum pressure in less than 300 ms.

  6. Recent Advances in the Control of Piezoelectric Actuators

    Directory of Open Access Journals (Sweden)

    Ziqiang Chi


    Full Text Available The micro/nano positioning field has made great progress towards enabling the advance of micro/nano technology. Micro/nano positioning stages actuated by piezoelectric actuators are the key devices in micro/nano manipulation. The control of piezoelectric actuators has emerged as a hot topic in recent years. Piezoelectric materials have inherent hysteresis and creep nonlinearity, which can reduce the accuracy of the manipulation, even causing the instability of the whole system. Remarkable efforts have been made to compensate for the nonlinearity of piezoelectric actuation through the mathematical modelling and control approaches. This paper provides a review of recent advances on the control of piezoelectric actuators. After a brief introduction of basic components of typical piezoelectric micro/nano positioning platforms, the working principle and modelling of piezoelectric actuators are outlined in this paper. This is followed with the major control method and recent progress is presented in detail. Finally, some open issues and future work on the control of piezoelectric actuators are extensively discussed.

  7. Design and investigation of a linear smart actuator (United States)

    Krishna Chaitanya, S.; Dhanalakshmi, K.


    Motors are nearly the sole constituents for actuation and driving applications, but there exist cases where their use proves to be impractical. Shape memory alloy (SMA), then revolutionized the actuator technology, thereby opening the door for new ideas and designs and with it what seemed unfeasible in the past have now become challenging. Many conventional actuators and sensors could be substituted with SMA, obtaining advantages in terms of reduction of weight, dimensions and its cost. SMAs are a group of metallic materials that revert to a predefined shape via phase transformation induced by a thermal procedure. Unlike metals that exhibit thermal expansion, SMA exhibits contraction when heated, which is larger by a hundredfold and exerts tremendous force for its small size. The focus of this work is to realize SMA wire as actuator which finds suitable applications (space, aerospace, biomechanics, etc.) where minimizing space, weight and cost are prime objectives. The accomplishments reported in this paper represent a significant development in the design of SMA actuator configurations for linear actuation. Report on design, fabrication and characterisation of the proposed system is presented. The design took advantage of converting the small linear displacement of the SMA wire into a large linear elastic motion under the influence of biasing element. From the results with control it is aspired that with further improvements on the design, the actuator can be utilized in enabling practical SMA technologies for potential robotic and commercial applications.

  8. Electromechanical actuation for thrust vector control applications (United States)

    Roth, Mary Ellen

    At present, actuation systems for the Thrust Vector Control (TVC) for launch vehicles are hydraulic systems. The Advanced Launch System (ALS), a joint initiative between NASA and the Air Force, is a launch vehicle that is designed to be cost effective, highly reliable and operationally efficient with a goal of reducing the cost per pound to orbit. As part of this initiative, an electromechanical actuation system is being developed as an attractive alternative to the hydraulic systems used today. NASA-Lewis is developing and demonstrating an Induction Motor Controller Actuation System with a 40 hp peak rating. The controller will integrate 20 kHz resonant link Power Management and Distribution (PMAD) technology and Pulse Population Modulation (PPM) techniques to implement Field Oriented Vector Control (FOVC) of a new advanced induction motor. Through PPM, multiphase variable frequency, variable voltage waveforms can be synthesized from the 20 kHz source. FOVC shows that varying both the voltage and frequency and their ratio (V/F), permits independent control of both torque and speed while operating at maximum efficiency at any point on the torque-speed curve. The driver and the FOVC will be microprocessor controlled. For increased system reliability, a Built-in Test (BITE) capability will be included. This involves introducing testability into the design of a system such that testing is calibrated and exercised during the design, manufacturing, maintenance and prelaunch activities. An actuator will be integrated with the motor controller for performance testing of the EMA TVC system. The design and fabrication of the motor controller is being done by General Dynamics Space Systems Division. The University of Wisconsin-Madison will assist in the design of the advanced induction motor and in the implementation of the FOVC theory. A 75 hp electronically controlled dynamometer will be used to test the motor controller in all four quadrants of operation using flight type

  9. The static actuation of dielectric elastomer actuators: how does pre-stretch improve actuation?

    Energy Technology Data Exchange (ETDEWEB)

    Kofod, Guggi [University of Potsdam, Institute of Physics, Advanced Condensed-Matter Physics, 14476 Potsdam (Germany)], E-mail:


    It has previously been shown that providing dielectric elastomer actuators with a level of pre-stretch can improve properties such as breakdown strength, actuation strain and efficiency. The actuation in such actuators depends on an interplay between the highly nonlinear hyperelastic stress-strain behaviour with the electrostatic Maxwell's stress; however, the direct effects of pre-stretch on the electromechanical coupling have still not been investigated in detail. We compare several experimental results found in the literature on the hyperelastic parameters of the Ogden model for the commonly used material VHB 4910, and introduce a more detailed and thus more accurate fit to a previous uniaxial stress-strain experiment. Electrostatic actuation models for a pure shear cuboid dielectric elastomer actuator with pre-stretch are introduced, for both intensive and extensive variables. For both intensive and extensive variables the constant strain (blocked stress or force) as well as the actuation strain is presented. It is shown how in the particular case of isotropic amorphous elastomers the pre-stretch does not affect the electromechanical coupling directly, and that the enhancement in actuation strain due to pre-stretch occurs through the alteration of the geometrical dimensions of the actuator. Also, the presence of the optimum load is explained as being due to the plateau region in the force-stretch curve, and it is shown that pre-stretch is not able to affect its position. Finally, it is shown how the simplified Ogden fit leads to entirely different conclusions for actuation strain in terms of extensive variables as does the detailed fit, emphasizing the importance of employing accurate hyperelastic models for the stress-stretch behaviour of the elastomer.

  10. The static actuation of dielectric elastomer actuators: how does pre-stretch improve actuation? (United States)

    Kofod, Guggi


    It has previously been shown that providing dielectric elastomer actuators with a level of pre-stretch can improve properties such as breakdown strength, actuation strain and efficiency. The actuation in such actuators depends on an interplay between the highly nonlinear hyperelastic stress-strain behaviour with the electrostatic Maxwell's stress; however, the direct effects of pre-stretch on the electromechanical coupling have still not been investigated in detail. We compare several experimental results found in the literature on the hyperelastic parameters of the Ogden model for the commonly used material VHB 4910, and introduce a more detailed and thus more accurate fit to a previous uniaxial stress-strain experiment. Electrostatic actuation models for a pure shear cuboid dielectric elastomer actuator with pre-stretch are introduced, for both intensive and extensive variables. For both intensive and extensive variables the constant strain (blocked stress or force) as well as the actuation strain is presented. It is shown how in the particular case of isotropic amorphous elastomers the pre-stretch does not affect the electromechanical coupling directly, and that the enhancement in actuation strain due to pre-stretch occurs through the alteration of the geometrical dimensions of the actuator. Also, the presence of the optimum load is explained as being due to the plateau region in the force-stretch curve, and it is shown that pre-stretch is not able to affect its position. Finally, it is shown how the simplified Ogden fit leads to entirely different conclusions for actuation strain in terms of extensive variables as does the detailed fit, emphasizing the importance of employing accurate hyperelastic models for the stress-stretch behaviour of the elastomer.

  11. Highly Adaptive Primary Mirror Having Embedded Actuators, Sensors, and Neural Control Project (United States)

    National Aeronautics and Space Administration — Xinetics has demonstrated the technology required to fabricate a self-compensating highly adaptive silicon carbide primary mirror system having embedded actuators,...

  12. High Bandwidth Rotary Fast Tool Servos and a Hybrid Rotary/Linear Electromagnetic Actuator

    Energy Technology Data Exchange (ETDEWEB)

    Montesanti, Richard Clement [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)


    This thesis describes the development of two high bandwidth short-stroke rotary fast tool servos and the hybrid rotary/linear electromagnetic actuator developed for one of them. Design insights, trade-o® methodologies, and analytical tools are developed for precision mechanical systems, power and signal electronic systems, control systems, normal-stress electromagnetic actuators, and the dynamics of the combined systems.

  13. Novel compliant actuator for wearable robotics applications. (United States)

    Claros, M; Soto, R; Rodríguez, J J; Cantú, C; Contreras-Vidal, José L


    In the growing fields of wearable robotics, rehabilitation robotics, prosthetics, and walking robots, variable impedance and force actuators are being designed and implemented because of their ability to dynamically modulate the intrinsic viscoelastic properties such as stiffness and damping. This modulation is crucial to achieve an efficient and safe human-robot interaction that could lead to electronically generate useful emergent dynamical behaviors. In this work we propose a novel actuation system in which is implemented a control scheme based on equilibrium forces for an active joint capable to provide assistance/resistance as needed and also achieve minimal mechanical impedance when tracking the movement of the user limbs. The actuation system comprises a DC motor with a built in speed reducer, two force-sensing resistors (FSR), a mechanism which transmits to the FSRs the torque developed in the joint and a controller which regulate the amount of energy that is delivered to the DC motor. The proposed system showed more impedance reduction, by the effect of the controlled contact forces, compared with the ones in the reviewed literature.

  14. Embodying Desired Behavior in Variable Stiffness Actuators

    NARCIS (Netherlands)

    Visser, L.C.; Stramigioli, Stefano; Bicchi, Antonio


    Variable stiffness actuators are a class of actuators with the capability of changing their apparent output stiffness independently from the actuator output position. This is achieved by introducing internally a number of compliant elements, and internal actuated degrees of freedom that determine

  15. Energy-Efficient Variable Stiffness Actuators

    NARCIS (Netherlands)

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


    Variable stiffness actuators are a particular class of actuators that is characterized by the property that the apparent output stiffness can be changed independent of the output position. To achieve this, variable stiffness actuators consist of a number of elastic elements and a number of actuated

  16. Vibration analysis of composite laminate plate excited by piezoelectric actuators. (United States)

    Her, Shiuh-Chuan; Lin, Chi-Sheng


    Piezoelectric materials can be used as actuators for the active vibration control of smart structural systems. In this work, piezoelectric patches are surface bonded to a composite laminate plate and used as vibration actuators. A static analysis based on the piezoelectricity and elasticity is conducted to evaluate the loads induced by the piezoelectric actuators to the host structure. The loads are then employed to develop the vibration response of a simply supported laminate rectangular plate excited by piezoelectric patches subjected to time harmonic voltages. An analytical solution of the vibration response of a simply supported laminate rectangular plate under time harmonic electrical loading is obtained and compared with finite element results to validate the present approach. The effects of location and exciting frequency of piezoelectric actuators on the vibration response of the laminate plate are investigated through a parametric study. Numerical results show that modes can be selectively excited, leading to structural vibration control.

  17. Mathematical analysis of actuator forces in a scissor lift (United States)

    Spackman, H.


    In 1985, NCCOSC began development of a tele-operated vehicle as part of the U.S. Marine Corps' Ground-Air Tele-Robotics Systems Program. One of the required vehicle components was a rigid, light-weight, and compact lift mechanism capable of deploying a surveillance package 10 feet above the vehicle bed. The lift mechanism that was eventually built and implemented was a 3-level scissor lift. In order to analyze the forces throughout the lift structure, a set of mathematical equations was derived. From these equations it was discovered that prudent placement of a lift's actuator can significantly reduce the forces required of the actuator and the stress levels in the adjacent scissor members. The purpose of this paper is to present the equations that were derived for analyzing the actuator forces. Using these equations, a designer can quickly determine the optimal locations for mounting an actuator and the resulting forces.

  18. Electrically Actuated Antiglare Rear-View Mirror Based on a Shape Memory Alloy Actuator (United States)

    Luchetti, T.; Zanella, A.; Biasiotto, M.; Saccagno, A.


    This article focuses on the experience of Centro Ricerche FIAT (CRF) regarding the development of shape memory alloy (SMA) actuators, and addressed some new design approaches which have been defined. Specific characteristics of shape memory materials, such as the efficiency of the transformation, have oriented the design of actuators toward occasionally used devices. The antiglare manual mechanism, incorporated in the internal rear-view mirror of a car, fits this new approach well. An antiglare rear-view mirror is a system capable of detecting a glare situation during night-time driving in order to automatically switch the mirror plane so as not to distract the driver. The low forces required, together with the silent, bi-stable movement are suitable for the use of a SMA actuator in this application. In the first part of the paper, the conceptual design is illustrated and a preliminary overview of the working principle is provided together with a series of considerations regarding the kinematics and the layout of electronic sensors in order to realize a fully controlled mechatronic prototype. Before concluding, the description of the realization of a working prototype is presented. The prototype of the EAGLE (Electrically Actuated antiGLare rEar-view mirror) system has provided experimental confirmation that such a device can satisfy fatigue and functional test requirements, thus offering the opportunity to spread the use of SMA devices in the automotive field.

  19. Novel Cryogenic Actuator Development Project (United States)

    National Aeronautics and Space Administration —  New thin film low friction coating technologies have recently been developed and matured to the point for use in this IRAD actuator work.The new novel...

  20. A bistable electromagnetically actuated rotary gate microvalve (United States)

    Luharuka, Rajesh; Hesketh, Peter J.


    Two types of rotary gate microvalves are developed for flow modulation in microfluidic systems. These microvalves have been tested for an open flow rate of up to 100 sccm and operate under a differential pressure of 6 psig with flow modulation of up to 100. The microvalve consists of a suspended gate that rotates in the plane of the chip to regulate flow through the orifice. The gate is suspended by a novel fully compliant in-plane rotary bistable micromechanism (IPRBM) that advantageously constrains the gate in all degrees of freedom except for in-plane rotational motion. Multiple inlet/outlet orifices provide flexibility of operating the microvalve in three different flow configurations. The rotary gate microvalve is switched with an external electromagnetic actuator. The suspended gate is made of a soft magnetic material and its electromagnetic actuation is based on the operating principle of a variable-reluctance stepper motor.

  1. Climbing robot actuated by meso-hydraulic artificial muscles (United States)

    Bryant, Matthew; Fitzgerald, Jason; Miller, Samuel; Saltzman, Jonah; Kim, Sangkyu; Lin, Yong; Garcia, Ephrahim


    This paper presents the design, construction, experimental characterization, and system testing of a legged, wall-climbing robot actuated by meso-scale hydraulic artificial muscles. While small wall-climbing robots have seen increased research attention in recent years, most authors have primarily focused on designs for the gripping and adhesion of the robot to the wall, while using only standard DC servo-motors for actuation. This project seeks to explore and demonstrate a different actuation mechanism that utilizes hydraulic artificial muscles. A four-limb climbing robot platform that includes a full closed-loop hydraulic power and control system, custom hydraulic artificial muscles for actuation, an on-board microcontroller and RF receiver for control, and compliant claws with integrated sensing for gripping a variety of wall surfaces has been constructed and is currently being tested to investigate this actuation method. On-board power consumption data-logging during climbing operation, analysis of the robot kinematics and climbing behavior, and artificial muscle force-displacement characterization are presented to investigate and this actuation method.

  2. Modeling and control of precision actuators

    CERN Document Server

    Kiong, Tan Kok


    IntroductionGrowing Interest in Precise ActuatorsTypes of Precise ActuatorsApplications of Precise ActuatorsNonlinear Dynamics and ModelingHysteresisCreepFrictionForce RipplesIdentification and Compensation of Preisach Hysteresis in Piezoelectric ActuatorsSVD-Based Identification and Compensation of Preisach HysteresisHigh-Bandwidth Identification and Compensation of Hysteretic Dynamics in Piezoelectric ActuatorsConcluding RemarksIdentification and Compensation of Frict

  3. Soft Pneumatic Actuators for Rehabilitation

    Directory of Open Access Journals (Sweden)

    Guido Belforte


    Full Text Available Pneumatic artificial muscles are pneumatic devices with practical and various applications as common actuators. They, as human muscles, work in agonistic-antagonistic way, giving a traction force only when supplied by compressed air. The state of the art of soft pneumatic actuators is here analyzed: different models of pneumatic muscles are considered and evolution lines are presented. Then, the use of Pneumatic Muscles (PAM in rehabilitation apparatus is described and the general characteristics required in different applications are considered, analyzing the use of proper soft actuators with various technical properties. Therefore, research activity carried out in the Department of Mechanical and Aerospace Engineering in the field of soft and textile actuators is presented here. In particular, pneumatic textile muscles useful for active suits design are described. These components are made of a tubular structure, with an inner layer of latex coated with a deformable outer fabric sewn along the edge. In order to increase pneumatic muscles forces and contractions Braided Pneumatic Muscles are studied. In this paper, new prototypes are presented, based on a fabric construction and various kinds of geometry. Pressure-force-deformation tests results are carried out and analyzed. These actuators are useful for rehabilitation applications. In order to reproduce the whole upper limb movements, new kind of soft actuators are studied, based on the same principle of planar membranes deformation. As an example, the bellows muscle model and worm muscle model are developed and described. In both cases, wide deformations are expected. Another issue for soft actuators is the pressure therapy. Some textile sleeve prototypes developed for massage therapy on patients suffering of lymph edema are analyzed. Different types of fabric and assembly techniques have been tested. In general, these Pressure Soft Actuators are useful for upper/lower limbs treatments

  4. Dielectric Elastomer Actuators for Microfluidics


    Maffli, Luc; Rosset, Samuel; Shea, Herbert


    One of the goals of microfluidics is to bring a whole laboratory processing chain on a few square centimeters, Lab-On-Chips (LOC). But current LOCs require many heavy and power-consuming off-chip controls like pneumatics, pumps and valves, which keep the small chip bound to the lab. Miniaturized Dielectric Elastomer Actuators (DEA) are excellent candidates to make LOC truly portable, since they combine electrical actuation, large stroke volumes and high output forces. We report on the use of ...

  5. Investigation of the vdW Force-Induced Instability in Nano-scale Actuators Fabricated form Cylindrical Nanowires

    Directory of Open Access Journals (Sweden)

    Rahman Soroush


    Full Text Available The presence of van der Waals (vdW force can lead to mechanical instability in freestanding nano-scale actuators. Most of the previous researches in this area have exclusively focused on modeling the instability in actuators with one actuating components. While, less attention has been paid to actuators consist of two actuating components. Herein, the effect of the vdW force on the instability of freestanding actuators with two parallel actuating components is investigated. Conventional configurations including cantilever and double-clamped geometries are investigated. A continuum mechanics theory in conjunction with Euler-beam model is applied to obtain governing equations of the systems. The nonlinear governing equations of the actuators are solved using two different approaches, i.e. the modified Adomian decomposition and the finite difference method. The maximum length of the nanowire and minimum initial gap which prevents the instability is computed.

  6. Piezoelectric line moment actuator for active radiation control from light-weight structures (United States)

    Jandak, Vojtech; Svec, Petr; Jiricek, Ondrej; Brothanek, Marek


    This article outlines the design of a piezoelectric line moment actuator used for active structural acoustic control. Actuators produce a dynamic bending moment that appears in the controlled structure resulting from the inertial forces when the attached piezoelectric stripe actuators start to oscillate. The article provides a detailed theoretical analysis necessary for the practical realization of these actuators, including considerations concerning their placement, a crucial factor in the overall system performance. Approximate formulas describing the dependency of the moment amplitude on the frequency and the required electric voltage are derived. Recommendations applicable for the system's design based on both theoretical and empirical results are provided.

  7. Force Characteristics of the H-module Linear Actuator with Varying Tooth-shift-distance

    DEFF Research Database (Denmark)

    Liu, Xiao; Chen, Zhe; Lu, Kaiyuan


    The large normal force of a single-sided linear actuator may cause vibration, noise and reduce the positioning accuracy. To overcome these disadvantages, a new H-module linear actuator (HMLA) is proposed to reduce effectively the normal force without using expensive air suspension system or assis......The large normal force of a single-sided linear actuator may cause vibration, noise and reduce the positioning accuracy. To overcome these disadvantages, a new H-module linear actuator (HMLA) is proposed to reduce effectively the normal force without using expensive air suspension system...

  8. Shape Control of Solar Collectors Using Shape Memory Alloy Actuators (United States)

    Lobitz, D. W.; Grossman, J. W.; Allen, J. J.; Rice, T. M.; Liang, C.; Davidson, F. M.


    Solar collectors that are focused on a central receiver are designed with a mechanism for defocusing the collector or disabling it by turning it out of the path of the sun's rays. This is required to avoid damaging the receiver during periods of inoperability. In either of these two cases a fail-safe operation is very desirable where during power outages the collector passively goes to its defocused or deactivated state. This paper is principally concerned with focusing and defocusing the collector in a fail-safe manner using shape memory alloy actuators. Shape memory alloys are well suited to this application in that once calibrated the actuators can be operated in an on/off mode using a minimal amount of electric power. Also, in contrast to other smart materials that were investigated for this application, shape memory alloys are capable of providing enough stroke at the appropriate force levels to focus the collector. Design and analysis details presented, along with comparisons to test data taken from an actual prototype, demonstrate that the collector can be repeatedly focused and defocused within accuracies required by typical solar energy systems. In this paper the design, analysis and testing of a solar collector which is deformed into its desired shape by shape memory alloy actuators is presented. Computations indicate collector shapes much closer to spherical and with smaller focal lengths can be achieved by moving the actuators inward to a radius of approximately 6 inches. This would require actuators with considerably more stroke and some alternate SMA actuators are currently under consideration. Whatever SMA actuator is finally chosen for this application, repeatability and fatigue tests will be required to investigate the long term performance of the actuator.

  9. Disposable Fluidic Actuators for Miniature In-Vivo Surgical Robotics. (United States)

    Pourghodrat, Abolfazl; Nelson, Carl A


    Fusion of robotics and minimally invasive surgery (MIS) has created new opportunities to develop diagnostic and therapeutic tools. Surgical robotics is advancing from externally actuated systems to miniature in-vivo robotics. However, with miniaturization of electric-motor-driven surgical robots, there comes a trade-off between the size of the robot and its capability. Slow actuation, low load capacity, sterilization difficulties, leaking electricity and transferring produced heat to tissues, and high cost are among the key limitations of the use of electric motors in in-vivo applications. Fluid power in the form of hydraulics or pneumatics has a long history in driving many industrial devices and could be exploited to circumvent these limitations. High power density and good compatibility with the in-vivo environment are the key advantages of fluid power over electric motors when it comes to in-vivo applications. However, fabrication of hydraulic/pneumatic actuators within the desired size and pressure range required for in-vivo surgical robotic applications poses new challenges. Sealing these types of miniature actuators at operating pressures requires obtaining very fine surface finishes which is difficult and costly. The research described here presents design, fabrication, and testing of a hydraulic/pneumatic double-acting cylinder, a limited-motion vane motor, and a balloon-actuated laparoscopic grasper. These actuators are small, seal-less, easy to fabricate, disposable, and inexpensive, thus ideal for single-use in-vivo applications. To demonstrate the ability of these actuators to drive robotic joints, they were modified and integrated in a robotic arm. The design and testing of this surgical robotic arm are presented to validate the concept of fluid-power actuators for in-vivo applications.

  10. Investigations on Actuator Dynamics through Theoretical and Finite Element Approach

    Directory of Open Access Journals (Sweden)

    Somashekhar S. Hiremath


    Full Text Available This paper gives a new approach for modeling the fluid-structure interaction of servovalve component-actuator. The analyzed valve is a precision flow control valve-jet pipe electrohydraulic servovalve. The positioning of an actuator depends upon the flow rate from control ports, in turn depends on the spool position. Theoretical investigation is made for No-load condition and Load condition for an actuator. These are used in finite element modeling of an actuator. The fluid-structure-interaction (FSI is established between the piston and the fluid cavities at the piston end. The fluid cavities were modeled with special purpose hydrostatic fluid elements while the piston is modeled with brick elements. The finite element method is used to simulate the variation of cavity pressure, cavity volume, mass flow rate, and the actuator velocity. The finite element analysis is extended to study the system's linearized response to harmonic excitation using direct solution steady-state dynamics. It was observed from the analysis that the natural frequency of the actuator depends upon the position of the piston in the cylinder. This is a close match with theoretical and simulation results. The effect of bulk modulus is also presented in the paper.

  11. Design, testing and control of a magnetorheological actuator for assistive knee braces (United States)

    Chen, J. Z.; Liao, W. H.


    This paper is aimed at developing a smart actuator for assistive knee braces to provide assistance to disabled or elderly people with mobility problems. A magnetorheological (MR) actuator is developed to be used in assistive knee braces to provide controllable torque. The MR actuator can work as a brake or a clutch. When active torque is needed, the DC motor works and the MR actuator functions as a clutch to transfer the torque generated by the motor to the leg; when passive torque is desired, the DC motor is turned off and the MR actuator functions as a brake to provide controllable passive torque. The prototype of the developed MR actuator is fabricated and experiments are carried out to investigate the characteristics of the MR actuator. The results show that the MR actuator is able to provide sufficient torque needed for normal human activities. Adaptive control is proposed for controlling the MR actuator. Anti-windup strategy is used to achieve better control performance. Experiments on the MR actuator under control are also performed to study the torque tracking ability of the system.

  12. Microfabricated actuators and their application to optics

    Energy Technology Data Exchange (ETDEWEB)

    Sniegowski, J.J.; Garcia, E.J.


    Several authors have given overviews of microelectromechanical systems, including microactuators. In our presentation we will review some of these results, and provide a brief description of the basic principles of operation, fabrication, and application, of a few selected microactuators (electrostatic and surface tension driven). We present a description of a three-level mechanical polysilicon surface-micromachining technology with a discussion of the advantages of this level of process complexity. This technology, is capable of forming complex, batch-fabricated, interconnected, and interactive, microactuated micromechanisms which include optical elements. The inclusion of a third deposited layer of mechanical polysilicon greatly extends the degree of complexity available for micromechanism design. Two examples of microactuators fabricated using this process are provided to illustrate the capabilities and usefulness of the technology. The first actuator is an example of a novel actuation mechanism based on the effect of surface tension at these micro-scale dimensions and of a microstructure within a microstructure. The second is a comb-drive-based microengine which has direct application as a drive and power source for micro optical elements, specifically, micro mirrors and micro shutters. This design converts linear oscillatory motion from electrostatic comb drive actuators into rotational motion via a direct linkage connection. The microengine provides output in the form of a continuously rotating output gear that is capable of delivering drive torque to a micromechanism.

  13. Electrowetting Actuation of Polydisperse Nanofluid Droplets

    Directory of Open Access Journals (Sweden)

    Crismar Patacsil


    Full Text Available We present results of electrowetting experiments employing droplets formed from aqueous suspensions of Au nanoparticles. A planar electrowetting system, consisting of a Pt wire electrode and a bottom Cu electrode with an insulating silicone layer, is used to observe changes in droplet contact angle when an external electric field is applied. The equilibrium contact angle at 0 V decreases with increasing nanoparticle concentration, dropping from 100.4° for pure deionized water to 94.7° for a 0.5 μM nanofluid. Increasing the nanoparticle content also lowers the required voltage for effective actuation. With actuation at 15 V, contact angle decreases by 9% and 35% for droplets formed from pure water and a 0.5 μM nanoparticle suspension, respectively. Contact angle saturation is observed with nanofluid droplets, with the threshold voltage decreasing as nanoparticle concentration rises. Maximum droplet actuation before contact angle saturation is achieved at only 10 V for a concentration of 0.5 μM. A proposed mechanism for the enhanced electrowetting response of a nanofluid droplet involves a reduction in surface tension of the droplet as nanoparticles accumulate at the liquid-vapor interface.

  14. Dynamic Electromechanical Coupling of Piezoelectric Bending Actuators

    Directory of Open Access Journals (Sweden)

    Mostafa R. A. Nabawy


    Full Text Available Electromechanical coupling defines the ratio of electrical and mechanical energy exchanged during a flexure cycle of a piezoelectric actuator. This paper presents an analysis of the dynamic electromechanical coupling factor (dynamic EMCF for cantilever based piezoelectric actuators and provides for the first time explicit expressions for calculation of dynamic EMCF based on arrangement of passive and active layers, layer geometry, and active and passive materials selection. Three main cantilever layer configurations are considered: unimorph, dual layer bimorph and triple layer bimorph. The actuator is modeled using standard constitutive dynamic equations that relate deflection and charge to force and voltage. A mode shape formulation is used for the cantilever dynamics that allows the generalized mass to be the actual mass at the first resonant frequency, removing the need for numerical integration in the design process. Results are presented in the form of physical insight from the model structure and also numerical evaluations of the model to provide trends in dynamic EMCF with actuator design parameters. For given material properties of the active and passive layers and given system overall damping ratio, the triple layer bimorph topology is the best in terms of theoretically achievable dynamic EMCF, followed by the dual layer bimorph. For a damping ratio of 0.035, the dynamic EMCF for an example dual layer bimorph configuration is 9% better than for a unimorph configuration. For configurations with a passive layer, the ratio of thicknesses for the passive and active layers is the primary geometric design variable. Choice of passive layer stiffness (Young’s modulus relative to the stiffness of the material in the active layer is an important materials related design choice. For unimorph configurations, it is beneficial to use the highest stiffness possible passive material, whereas for triple layer bimorph configurations, the passive

  15. Utilization of electroactive polymer actuators in micromixing and in extended-life biosensor applications (United States)

    Ho, Vinh; Shimada, Mark; Szeto, David; Casadevall i Solvas, Xavier; Scott, Daniel; Dolci, Luisa Stella; Kulinsky, Lawrence; Daunert, Sylvia; Madou, Marc


    Polypyrrole (PPy)-based microactuators hold a promise for a wide variety of engineering applications from robotics and microassembly to biosensors and drug delivery systems. The main advantages of using PPy/Au actuator structures (vs competing solid-state actuator technologies) include ease of fabrication, low actuation energy, and large motion range of microactuators. We present advances in two areas of application - in the extended-life biosensor platform and in micromixers.

  16. Deriving a Generalized, Actuator Position-Independent Expression for the Force Output of a Scissor Lift


    Saxena, Amay


    Scissor lifts, a staple of mechanical design, especially in competitive robotics, are a type of linkage that can be used to raise a load to some height, when acted upon by some force, usually exerted by an actuator. The position of this actuator, however, can affect the mechanical advantage and velocity ratio of the system. Hence, there needs to be a concrete way to analytically compare different actuator positions. However, all current research into the analysis of scissor lifts either focus...

  17. Design and Evaluation of a Direct Drive Valve Actuated by Piezostack Actuator

    Directory of Open Access Journals (Sweden)

    Juncheol Jeon


    Full Text Available This paper presents performance characteristics of a new type of direct drive valve (DDV system driven by a piezostack actuator. The flexible beam mechanism is employed to amplify the output displacement from the piezostack actuator. After describing the operational principle of the proposed piezo DDV system, the governing equation of the whole piezo DDV system is then obtained by integrating the equations of the valve components. Based on the proposed model, significant structural components of the piezo DDV system are designed in order to achieve operational requirements (operating frequency: over 100 Hz; flow rate: 20 liter/Min.. An optimal design method is proposed for obtaining the geometry of the flexible beam mechanism by considering spool displacement, required operating frequency, and available space of the valve. After deciding the specific geometric dimensions of the piezo DDV system, a PID control algorithm is designed to enforce the spool position to the desired position trajectories by activating the piezostack actuator. Characteristics and control performances of the proposed piezo DDV system are evaluated using the MATLAB Simulink.

  18. Surface texture change on-demand and microfluidic devices based on thickness mode actuation of dielectric elastomer actuators (DEAs) (United States)

    Ankit, Ankit; Nguyen, Anh Chien; Mathews, Nripan


    Tactile feedback devices and microfluidic devices have huge significance in strengthening the area of robotics, human machine interaction and low cost healthcare. Dielectric Elastomer Actuators (DEAs) are an attractive alternative for both the areas; offering the advantage of low cost and simplistic fabrication in addition to the high actuation strains. The inplane deformations produced by the DEAs can be used to produce out-of-plane deformations by what is known as the thickness mode actuation of DEAs. The thickness mode actuation is achieved by adhering a soft passive layer to the DEA. This enables a wide area of applications in tactile applications without the need of complex systems and multiple actuators. But the thickness mode actuation has not been explored enough to understand how the deformations can be improved without altering the material properties; which is often accompanied with increased cost and a trade off with other closely associated material properties. We have shown the effect of dimensions of active region and non-active region in manipulating the out-of-plane deformation. Making use of this, we have been able to demonstrate large area devices and complex patterns on the passive top layer for the surface texture change on-demand applications. We have also been able to demonstrate on-demand microfluidic channels and micro-chambers without the need of actually fabricating the channels; which is a cost incurring and cumbersome process.

  19. submitter On the identification of Hammerstein systems in the presence of an input hysteretic nonlinearity with nonlocal memory: Piezoelectric actuators – an experimental case study

    CERN Document Server

    Butcher, Mark; Masi, Alessandro


    The identification problem of the linear dynamic part of piezo based actuators is addressed in this paper, exploiting the use of binary signals, specifically the pseudo random binary sequences (PRBS). Due to the presence of nonlocal memory hysteretic behavior in piezoelectric active materials, the dependence of the identification results on this strongly nonlinear effect is analyzed and useful guidelines for the design of the PRBS stimulating signal are derived. Moreover, some properties of hysteresis like cancellation and congruency are experimentally analyzed and their effects on the identification process are discussed. Finally, the use of a hysteresis compensation strategy in the identification process is evaluated and discussed.

  20. Impact of pulsed jet actuators on aircraft mass and fuel consumption

    NARCIS (Netherlands)

    Bertels, F.G.A.; van Dijk, R.E.C.; Elmendorp, R.J.M.; Vos, R.


    Pulsed jet actuators (PJAs) are one of the candidate technologies to be integrated in Fowler flaps to increase the maximum lift coefficient of transport aircraft in the landing configuration. The total system consists of the actuators plus sensors, a piping system to supply pressurized air and a

  1. The response of a flat plate boundary layer to an orthogonally arranged dielectric barrier discharge actuator (United States)

    Gibson, B. A.; Arjomandi, M.; Kelso, R. M.


    The jetting characteristics of dielectric barrier discharge (DBD) actuators make these devices suitable for augmenting boundary layer flows. The associated change to the hydrodynamic stability of the fluid arising from the actuator provides a mechanism through which a DBD-based laminar flow control (LFC) system can be developed. Historically, DBD actuators with electrodes arranged parallel to each other have been used for LFC with mixed results. An alternative is to use an actuator with electrodes placed orthogonally to each other. Orthogonally arranged actuators exhibit different jetting characteristics to conventional ones, and as such understanding the effect that these actuators have on the mean velocity profile within a flat plate boundary layer is of significant interest to the development of DBD-based LFC technology. In this investigation, the velocity distribution within a flat plate boundary layer in a zero pressure gradient is measured in response to the operation of an orthogonally arranged actuator. The results suggest that significant thinning of the boundary layer can be realized with an orthogonally arranged actuator, over a short distance downstream of the device, and used in conjunction with a subtle suction effect, this thinning can be exacerbated. However, further downstream, rapid thickening of the layer, supported by a decrease in the shape factor of the flow suggests that the layer becomes unstable, in an accelerated fashion, to the presence of the actuator. Hence the stability of the layer is found to be significantly altered by the presence of the orthogonally arranged actuator, a requisite for a LFC system. However, since the actuator produces a destabilizing effect, the development of a successful LFC system based on orthogonal actuators will require further work.

  2. Prediction of dry ice mass for firefighting robot actuation (United States)

    Ajala, M. T.; Khan, Md R.; Shafie, A. A.; Salami, MJE; Mohamad Nor, M. I.


    The limitation in the performance of electric actuated firefighting robots in high-temperature fire environment has led to research on the alternative propulsion system for the mobility of firefighting robots in such environment. Capitalizing on the limitations of these electric actuators we suggested a gas-actuated propulsion system in our earlier study. The propulsion system is made up of a pneumatic motor as the actuator (for the robot) and carbon dioxide gas (self-generated from dry ice) as the power source. To satisfy the consumption requirement (9cfm) of the motor for efficient actuation of the robot in the fire environment, the volume of carbon dioxide gas, as well as the corresponding mass of the dry ice that will produce the required volume for powering and actuation of the robot, must be determined. This article, therefore, presents the computational analysis to predict the volumetric requirement and the dry ice mass sufficient to power a carbon dioxide gas propelled autonomous firefighting robot in a high-temperature environment. The governing equation of the sublimation of dry ice to carbon dioxide is established. An operating time of 2105.53s and operating pressure ranges from 137.9kPa to 482.65kPa were achieved following the consumption rate of the motor. Thus, 8.85m3 is computed as the volume requirement of the CAFFR while the corresponding dry ice mass for the CAFFR actuation ranges from 21.67kg to 75.83kg depending on the operating pressure.

  3. A dielectric electroactive polymer generator-actuator model: modeling, identification, and dynamic simulation (United States)

    Ihlefeld, Curtis M.; Qu, Zhihua


    Dielectric electroactive polymer membranes have been shown to have capabilities both as actuators and generators. Recent models of actuators have shown input to output dynamics that link the electrical energy input to the acceleration of a mass. Models such as these are useful for implementing closed loop control systems and will be necessary in the future for the construction of robust and fault tolerant controls. On the other hand, explanations of the generator behavior of dielectric EAP devices tend to ignore full dynamics. In this paper it is demonstrated that an EAP actuator model with full electrical-mechanical dynamics can be used as a generator model with the generator input force equivalent to the actuator disturbance force. Since the generator and actuator models are equivalent, it can be shown how disturbance inputs can cause energy surges back toward the electrical input. Simulations and experimental results are provided of a device model that describes generation and actuation.

  4. Optoelectrowetting for continuous microdroplet actuation (United States)

    Collier, Christopher M.; Hill, Kyle A.; DeWachter, Mark A.; Huizing, Alex M.; Holzman, Jonathan F.


    Microfluidics technologies have received great attention and appear in many bioanalyses applications. A recent microfluidics subset has appeared as droplet-based digital microfluidics (DMF). Here, microdroplets are manipulated in a two-dimensional on-chip plane using electric fields, contrasting the one-dimensional pressure-based channel flow of continuous flow microfluidics. These DMF systems fundamentally offer reconfigurability, whereby one device performs many bioanalysis tasks. A subset of DMF systems called optoelectrowetting is also of recent interest due to its ability for intricate microdroplet routing processes in the on-chip plane. For an optoelectrowetting chip, the DMF structure is modified with optically triggered electrodes with arrayed photoconductive switches. The arrayed photoconductive switches are optically-activated so microdroplets in the vicinity are routed to the illuminated switch. Unfortunately, such systems still require intricate electrode arrays, limiting microdroplet actuation resolution by the electrode size. This work proposes an on-chip optofluidic device with a continuous and planar semiconductor layer as the photoconductive mechanism. An illuminated section of the semiconductor layer acts as a localized electrode, with the photogenerated charge-carriers attracting nearby microdroplets. Given this planar topology, the illuminating beam is used to move the microdroplets continuously over the on-chip plane with precise optical control. The resolution for such a process is ultimately limited by charge-carrier diffusion, so an alternative material, a nanocomposite, is introduced to the on-chip device design. The nanocomposite consists of 20 nm semiconductor nanoparticles embedded in an insulative polymer host. This gives restricted diffusion length, being on the nanometer-scale of the nanoparticle diameter. Experimental device operation is demonstrated.

  5. Wing Tip Drag Reduction at Nominal Take-Off Mach Number: An Approach to Local Active Flow Control with a Highly Robust Actuator System

    Directory of Open Access Journals (Sweden)

    Matthias Bauer


    Full Text Available This paper discusses wind tunnel test results aimed at advancing active flow control technology to increase the aerodynamic efficiency of an aircraft during take-off. A model of the outer section of a representative civil airliner wing was equipped with two-stage fluidic actuators between the slat edge and wing tip, where mechanical high-lift devices fail to integrate. The experiments were conducted at a nominal take-off Mach number of M = 0.2. At this incidence velocity, separation on the wing section, accompanied by increased drag, is triggered by the strong slat edge vortex at high angles of attack. On the basis of global force measurements and local static pressure data, the effect of pulsed blowing on the complex flow is evaluated, considering various momentum coefficients and spanwise distributions of the actuation effort. It is shown that through local intensification of forcing, a momentum coefficient of less than c μ = 0.6 % suffices to offset the stall by 2.4°, increase the maximum lift by more than 10% and reduce the drag by 37% compared to the uncontrolled flow.

  6. A Completely New Type of Actuator -or- This Ain't Your Grandfather's Internal Combustion Engine (United States)

    Gore, Brian W.; Hawkins, Gary F.; Hess, Peter A.; Moore, Teresa A.; Fournier, Eric W.


    A completely new type of actuator - one that is proposed for use in a variety of environments from sea to land to air to space - has been designed, patented, built, and tested. The actuator is loosely based on the principle of the internal combustion engine, except that it is a completely closed system, only requiring electrical input, and the working fuel is water. This paper outlines the theory behind the electrolysis- and ignition-based cycle upon which the actuator operates and describes the performance capability test apparatus and results for the actuator. A mechanism application that harnessed the unit s power to twist a scaled rotor blade is also highlighted.

  7. Performance of direct-driven flapping-wing actuator with piezoelectric single-crystal PIN-PMN-PT (United States)

    Ozaki, Takashi; Hamaguchi, Kanae


    We present a prototype flapping-wing actuator with a direct-driven mechanism to generate lift in micro- and nano-aerial vehicles. This mechanism has an advantage of simplicity because it has no transmission system between the actuator and wing. We fabricated the piezoelectric unimorph actuator from single-crystal PIN-PMN-PT, which achieved a lift force up to 1.45 mN, a value about 1.9 times larger than the mass of the actuator itself. This is the first reported demonstration of an insect-scale actuator with a direct-driven mechanism that can generate a lift force greater than its own weight.

  8. Hydraulic Actuators with Autonomous Hydraulic Supply for the Mainline Aircrafts

    Directory of Open Access Journals (Sweden)

    I. S. Shumilov


    Full Text Available Applied in the aircraft control systems, hydraulic servo actuators with autonomous hydraulic supply, so-called, hydraulic actuators of integrated configuration, i.e. combination of a source of hydraulic power and its load in the single unit, are aimed at increasing control system reliability both owing to elimination of the pipelines connecting the actuator to the hydraulic supply source, and owing to avoidance of influence of other loads failure on the actuator operability. Their purpose is also to raise control system survivability by eliminating the long pipeline communications and their replacing for the electro-conductive power supply system, thus reducing the vulnerability of systems. The main reason for a delayed application of the hydraulic actuators in the cutting-edge aircrafts was that such aircrafts require hydraulic actuators of considerably higher power with considerable heat releases, which caused an unacceptable overheat of the hydraulic actuators. Positive and negative sides of the hydraulic actuators, their alternative options of increased reliability and survivability, local hydraulic systems as an advanced alternative to independent hydraulic actuators are considered.Now to use hydraulic actuators in mainline aircrafts is inexpedient since there are the unfairly large number of the problems reducing, first and last, safety of flights, with no essential weight and operational advantages. Still works to create competitive hydraulic actuators ought to be continued.Application of local hydraulic systems (LHS will allow us to reduce length of pressure head and drain pipelines and mass of pipelines, as well as to raise their general fail-safety and survivability. Application of the LHS principle will allow us to use a majority of steering drive advantages. It is necessary to allocate especially the following:- ease of meeting requirements for the non-local spread of the engine weight;- essentially reducing length and weight of

  9. Elastic actuation for legged locomotion (United States)

    Cao, Chongjing; Conn, Andrew


    The inherent elasticity of dielectric elastomer actuators (DEAs) gives this technology great potential in energy efficient locomotion applications. In this work, a modular double cone DEA is developed with reduced manufacturing and maintenance time costs. This actuator can lift 45 g of mass (5 times its own weight) while producing a stroke of 10.4 mm (23.6% its height). The contribution of the elastic energy stored in antagonistic DEA membranes to the mechanical work output is experimentally investigated by adding delay into the DEA driving voltage. Increasing the delay time in actuation voltage and hence reducing the duty cycle is found to increase the amount of elastic energy being recovered but an upper limit is also noticed. The DEA is then applied to a three-segment leg that is able to move up and down by 17.9 mm (9% its initial height), which demonstrates the feasibility of utilizing this DEA design in legged locomotion.

  10. Metallic molybdenum disulfide nanosheet-based electrochemical actuators (United States)

    Acerce, Muharrem; Akdoğan, E. Koray; Chhowalla, Manish


    Actuators that convert electrical energy to mechanical energy are useful in a wide variety of electromechanical systems and in robotics, with applications such as steerable catheters, adaptive wings for aircraft and drag-reducing wind turbines. Actuation systems can be based on various stimuli, such as heat, solvent adsorption/desorption, or electrochemical action (in systems such as carbon nanotube electrodes, graphite electrodes, polymer electrodes and metals). Here we demonstrate that the dynamic expansion and contraction of electrode films formed by restacking chemically exfoliated nanosheets of two-dimensional metallic molybdenum disulfide (MoS2) on thin plastic substrates can generate substantial mechanical forces. These films are capable of lifting masses that are more than 150 times that of the electrode over several millimetres and for hundreds of cycles. Specifically, the MoS2 films are able to generate mechanical stresses of about 17 megapascals—higher than mammalian muscle (about 0.3 megapascals) and comparable to ceramic piezoelectric actuators (about 40 megapascals)—and strains of about 0.6 per cent, operating at frequencies up to 1 hertz. The actuation performance is attributed to the high electrical conductivity of the metallic 1T phase of MoS2 nanosheets, the elastic modulus of restacked MoS2 layers (2 to 4 gigapascals) and fast proton diffusion between the nanosheets. These results could lead to new electrochemical actuators for high-strain and high-frequency applications.

  11. Focus tunable device actuator based on ionic polymer metal composite (United States)

    Zhang, Yi-Wei; Su, Guo-Dung J.


    IPMC (Ionic Polymer Metallic Composite) is a kind of electroactive polymer (EAP) which is used as an actuator because of its low driving voltage and small size. The mechanism of IPMC actuator is due to the ionic diffusion when the voltage gradient is applied. In this paper, the complex IPMC fabrication such as Ag-IPMC be further developed in this paper. The comparison of response time and tip bending displacement of Pt-IPMC and Ag-IPMC will also be presented. We also use the optimized IPMC as the lens actuator integrated with curvilinear microlens array, and use the 3D printer to make a simple module and spring stable system. We also used modeling software, ANSYS Workbench, to confirm the effect of spring system. Finally, we successfully drive the lens system in 200μm stroke under 2.5V driving voltage within 1 seconds, and the resonant frequency is approximately 500 Hz.

  12. Polypyrrole Actuators for Tremor Suppression

    DEFF Research Database (Denmark)

    Skaarup, Steen; Mogensen, Naja; Bay, Lasse


    for the change of length and for the stiffness change are significantly different - the stiffness change being about 10 times faster. Both force measurements and Electrochemical Quartz Crystal Microbalance measurements indicate that the actuation process is complex and involves at least two different processes...... enter the polymer in a slower process driven by osmotic pressure. Earlier work has tended to focus on achieving the maximum length change, therefore taking the time needed to include all processes. However, since the slower process described above is associated with the lowest strength of the actuator...

  13. Dielectric Elastomers for Actuation and Energy Harvesting (United States)

    Brochu, Paul A.

    actuators. The fault-tolerance and improved interlayer adhesion was used to fabricate prestrained free-standing silicone actuators capable of stable long life actuation (>30,000 cycles at >20% strain and >500 cycles at ˜40% strain) while driving a load. Issues related to gradual electrode degradation are also addressed through the use of quasi-buckled electrodes. For generator purposes, the primary concerns are ensuring environmental stability, increasing energy density, lowering losses, and determining effective methods to couple the dielectric elastomer to natural energy sources. Using the results of this analysis, two material systems are explored: VHB acrylic elastomers at various prestrains and with various amounts of a stiffening additive, and a high energy density silicone-TiO2 nanocomposite elastomer with various amounts of additive. It is shown that increasing prestrain in the VHB acrylic system increases the energy density, while the stiffening additive has the effect of making the acrylic stiffer but results in increased losses, result in poorer performance. The silicone TiO2 composite demonstrates an increase in permittivity and stiffness with increasing additive while maintaining very high dielectric breakdown strength values. These increases are partially offset by small increases in mechanical and electrical losses. Calculations based on a simple model show that the generator energy density can be improved by a factor of 3 for a 20wt.% TiO2 loading at a strain of 50% in area. The calculated generator energy density values exceed the maximum values measured experimentally for highly prestrained VHB4910 acrylic elastomers. The focus on high energy density materials ignores the fact that not all applications require such a material, and that some applications may, in fact, benefit from the use of a softer material that is less intrusive. However, for lower energy density materials, parasitic losses due to electrode resistance and viscoelasticity play a larger

  14. Modular Actuators for Space Applications Project (United States)

    National Aeronautics and Space Administration — Rocketstar Robotics is proposing the development of a modern dual drive actuator. Rocketstar has put together numerous modern concepts for modular actuators that...

  15. Transputer Control of Hydraulic Actuators and Robots

    DEFF Research Database (Denmark)

    Conrad, Finn


    Results from a Danish mechatronics research program entitled IMCIA - Intelligent Control and Intelligent Actuators. The objective is development of intelligent actuators for intelligent motion control. A mechatronics test facility with a transputer controlled hydraulic robot suiteable for real...

  16. Magnetic Actuation of Self-Assembled DNA Hinges (United States)

    Lauback, S.; Mattioli, K.; Armstrong, M.; Miller, C.; Pease, C.; Castro, C.; Sooryakumar, R.

    DNA nanotechnology offers a broad range of applications spanning from the creation of nanoscale devices, motors and nanoparticle templates to the development of precise drug delivery systems. Central to advancing this technology is the ability to actuate or reconfigure structures in real time, which is currently achieved primarily by DNA strand displacement yielding slow actuation times (about 1-10min). Here we exploit superparamagnetic beads to magnetically actuate DNA structures which also provides a system to measure forces associated with molecular interactions. DNA nanodevices are folded using DNA origami, whereby a long single-stranded DNA is folded into a precise compact geometry using hundreds of short oligonucleotides. Our DNA nanodevice is a nanohinge from which rod shaped DNA nanostructures are polymerized into micron-scale filaments forming handles for actuation. By functionalizing one arm of the hinge and the filament ends, the hinge can be attached to a surface while still allowing an arm to rotate and the filaments can be labeled with magnetic beads enabling the hinge to be actuated almost instantaneously by external magnetic fields. These results lay the groundwork to establish real-time manipulation and direct force application of DNA constructs.

  17. Tailoring the actuation of ionic polymer metal composites (United States)

    Nemat-Nasser, Sia; Wu, Yongxian


    Ionic polymer-metal composites (IPMCs) are biomimetic actuators and sensors. A typical IPMC consists of a thin perfluorinated ionomer membrane, with noble metal electrodes plated on both faces, and neutralized with the necessary amount of cations. A cantilevered strip of IPMC responds to an electric stimulus by generating large bending motions and, conversely, produces an electric potential upon sudden bending deformations. IPMCs have been considered for potential applications in artificial muscles, robotic systems, and biomedical devices. By examining the underpinning mechanisms responsible for the actuation and the factors that affect IPMC's performance, novel methods to tailor its electro-mechanical response to obtain optimized actuation activities are developed and presented in this paper. By introducing various monovalent or multivalent single cations and cation combinations, diverse actuation behaviors can be obtained and optimal actuation activities can be identified. The experimental measurements show good agreement with the results obtained using the nano-scaled, physics-based model that was introduced by the first author to predict the actuation of IPMCs qualitatively and quantitatively. The bending motion of IPMCs can also be tailored by modifying the time variation of the applied direct or alternating current. We have discovered that the Nafion-based IPMC's initial motion towards the anode can be controlled and ultimately eliminated by applying a linearly increasing electric potential at a suitable rate. For Flemion-based IPMCs, the tip displacement towards the anode is always linearly related to the cation charge accumulation at the cathode. These results have significant bearing on verifying various IPMC actuation models.

  18. Soft Pneumatic Actuator Fascicles for High Force and Reliability. (United States)

    Robertson, Matthew A; Sadeghi, Hamed; Florez, Juan Manuel; Paik, Jamie


    Soft pneumatic actuators (SPAs) are found in mobile robots, assistive wearable devices, and rehabilitative technologies. While soft actuators have been one of the most crucial elements of technology leading the development of the soft robotics field, they fall short of force output and bandwidth requirements for many tasks. In addition, other general problems remain open, including robustness, controllability, and repeatability. The SPA-pack architecture presented here aims to satisfy these standards of reliability crucial to the field of soft robotics, while also improving the basic performance capabilities of SPAs by borrowing advantages leveraged ubiquitously in biology; namely, the structured parallel arrangement of lower power actuators to form the basis of a larger and more powerful actuator module. An SPA-pack module consisting of a number of smaller SPAs will be studied using an analytical model and physical prototype. Experimental measurements show an SPA pack to generate over 112 N linear force, while the model indicates the benefit of parallel actuator grouping over a geometrically equivalent single SPA scale as an increasing function of the number of individual actuators in the group. For a module of four actuators, a 23% increase in force production over a volumetrically equivalent single SPA is predicted and validated, while further gains appear possible up to 50%. These findings affirm the advantage of utilizing a fascicle structure for high-performance soft robotic applications over existing monolithic SPA designs. An example of high-performance soft robotic platform will be presented to demonstrate the capability of SPA-pack modules in a complete and functional system.

  19. The Overtone Fiddle: an Actuated Acoustic Instrument

    DEFF Research Database (Denmark)

    Overholt, Daniel


    The Overtone Fiddle is a new violin-family instrument that incorporates electronic sensors, integrated DSP, and physical actuation of the acoustic body. An embedded tactile sound transducer creates extra vibrations in the body of the Overtone Fiddle, allowing performer control and sensation via...... both traditional violin techniques, as well as extended playing techniques that incorporate shared man/machine control of the resulting sound. A magnetic pickup system is mounted to the end of the fiddle’s fingerboard in order to detect the signals from the vibrating strings, deliberately not capturing...

  20. Experimental identification of piezo actuator characteristic

    Directory of Open Access Journals (Sweden)

    Ľ. Miková


    Full Text Available This paper deals with piezoelectric material, which can be used as actuator for conversion of electrical energy to mechanical work. Test equipment has been developed for experimental testing of the piezoactuators. Piezoactivity of this actuator has non-linear characteristic. This type of actuator is used for in-pipe mechanism design.

  1. Carbon nanotube-polymer composite actuators (United States)

    Gennett, Thomas [Denver, CO; Raffaelle, Ryne P [Honeoye Falls, NY; Landi, Brian J [Rochester, NY; Heben, Michael J [Denver, CO


    The present invention discloses a carbon nanotube (SWNT)-polymer composite actuator and method to make such actuator. A series of uniform composites was prepared by dispersing purified single wall nanotubes with varying weight percents into a polymer matrix, followed by solution casting. The resulting nanotube-polymer composite was then successfully used to form a nanotube polymer actuator.

  2. Development and testing of a magnetorheological actuator for an assistive knee brace (United States)

    Chen, Jinzhou; Liao, Wei-Hsin


    This paper proposes an assistive knee brace that is aimed to provide assistance to old or disabled people. A magnetorheological (MR) actuator is developed to be used in assistive knee braces to provide controllable torque. The MR actuator consists of a DC motor and an MR brake/clutch. When active torque is needed, the DC motor works and the MR actuator functions as a clutch to transfer the torque generated by the motor to the leg; when passive torque is desired, the DC motor is turned off and the MR actuator functions as a brake to provide controllable passive torque. The prototype of this MR actuator is fabricated and experiments are carried out to investigate the characteristics of the MR actuator. The results show that the MR actuator is able to provide sufficient torque needed for normal human activities. Adaptive control is proposed for controlling the MR actuator. Experiments of the MR actuator under control are performed to study the torque tracking ability of the system.

  3. Performance prediction of circular dielectric electro-active polymers membrane actuators with various geometries (United States)

    Hau, Steffen; York, Alexander; Seelecke, Stefan


    Circular dielectric electro-active polymer (DEAP) membrane actuators are easy to manufacture and therefore can be uniquely designed to perform optimally for specific applications. The performance of these actuators is naturally dependent on the materials used, and also dictated by the specific geometry of the circular design. For a given overall actuator size, changing their internal geometry will directly change the force and stroke output. In addition the DEAP technology itself is a promising technology for constructing lightweight, cost and energy efficient sensor and actuator systems. Thus, several potential applications like pressure sensors, pumps, valves, micro-positioners and loudspeakers were already proposed. The circular DEAP membrane actuators used in this study consist of a silicone based elastomer, carbon ink based electrodes, and are held together with a stiff frame. Experimentally collected force-displacement curves for these actuators can be used to determine force and stroke output of the actuators as described by Hodgins et al. in. This work presents an efficient method to predict these force-displacement plots and thus stroke and force output for different actuator geometries. These results than can be used to adapt the actuator geometry to the needs of a specific application with its particular force and stroke requirements. The prediction method is based on an average stress-stretch calculation for training samples. The calculated stress-stretch data is then geometry independent and can be used to predict desired geometry dependent force-displacement data for stroke and force output analysis.

  4. Magnetostrictively actuated control flaps for vibration reduction in helicopter rotors

    Energy Technology Data Exchange (ETDEWEB)

    Millott, T.; Friedmann, P.P. [Univ. of California, Los Angeles, CA (United States). Mechanical, Aerospace and Nuclear Engineering Dept.


    High vibration levels can impose constraints on helicopter operations and hinder passenger acceptance. Vibration reduction using blade root pitch control introduces a significant power penalty and may adversely affect the airworthiness of the flight control system. Comparable levels of vibration reduction can be achieved using considerably less power through an actively controlled trailing edge flap mounted on the blade. Such a device would have no effect on helicopter airworthiness since it is controlled by a loop separate from the primary flight control system which utilizes the swashplate. Control flap actuation using the magnetostrictive material Terfenol-D is studied in this paper by designing a minimum weight actuator, subject to a set of actuation and stress constraints. The resulting device is capable of producing vibration reduction in excess of 90% at cruise conditions.

  5. Modeling and analysis of the electromechanical behavior of surface-bonded piezoelectric actuators using finite element method

    CERN Document Server

    Yu, Huangchao


    Piezoelectric actuators have been widely used to form a self-monitoring smart system to do Structural health monitoring (SHM). One of the most fundamental issues in using actuators is to determine the actuation effects being transferred from the actuators to the host structure. This report summaries the state of the art of modeling techniques for piezoelectric actuators and provides a numerical analysis of the static and dynamic electromechanical behavior of piezoelectric actuators surface-bonded to an elastic medium under in-plane mechanical and electric loads using finite element method. Also case study is conducted to study the effect of material properties, bonding layer and loading frequency using static and harmonic analysis of ANSYS. Finally, stresses and displacements are determined, and singularity behavior at the tips of the actuator is proved. The results indicate that material properties, bonding layers and frequency have a significant influence on the stresses transferred to the host structure.

  6. Compliant actuation of rehabilitation robots

    NARCIS (Netherlands)

    Vallery, Heike; Veneman, J.F.; van Asseldonk, Edwin H.F.; Ekkelenkamp, R.; Buss, Martin; van der Kooij, Herman


    This article discusses the pros and cons of compliant actuation for rehabilitation robots on the example of LOPES, focusing on the cons. After illustrating the bandwidth limitations, a new result has been derived: if stability in terms of passivity of the haptic device is desired, the renderable

  7. Electro-active paper actuators (United States)

    Kim, Jaehwan; Seo, Yung B.


    In this paper, the actuation mechanism of electro-active paper (EAPap) actuators is addressed and the potential of the actuators is demonstrated. EAPap is a paper that produces large displacement with small force under an electrical excitation. EAPap is made with a chemically treated paper by constructing thin electrodes on both sides of the paper. When electrical voltage is applied on the electrodes the EAPap produces bending displacement. However, the displacement output has been unstable and degraded with timescale. To improve the bending performance of EAPap, different paper fibers - softwood, hardwood, bacteria cellulose, cellophane, carbon mixture paper, electrolyte containing paper and Korean traditional paper, in conjunction with additive chemicals, were tested. Two attempts were made to construct the electrodes: the direct use of aluminum foil and the gold sputtering technique. It was found that a cellophane paper exhibits a remarkable bending performance. When 2 MV m-1 excitation voltage was applied to the paper actuator, more than 3 mm tip displacement was observed from the 30 mm long paper beam. This is quite a low excitation voltage compared with that of other EAPs. Details of the experiments and results are addressed.

  8. The actuation of sound change

    NARCIS (Netherlands)

    Pinget, A.C.H.


    This dissertation is a sociophonetic study on sound change in progress. It addresses the actuation problem, i.e. the question as to why a particular change takes place in a particular language at a given time. The study is implemented in the framework of exemplar-based theories, which incorporates

  9. Explosive micro-bubble actuator

    NARCIS (Netherlands)

    van den Broek, D.M.


    Microactuators are key components in numerous microsystems, and in many applications strong and fast microactuators are required. The principles used to generate forces in the current actuators are not capable of fulfilling both requirements at the same time, so new principles have to be

  10. Design and Modeling of Polysilicon Electrothermal Actuators for a MEMS Mirror with Low Power Consumption

    Directory of Open Access Journals (Sweden)

    Miguel Lara-Castro


    Full Text Available Endoscopic optical-coherence tomography (OCT systems require low cost mirrors with small footprint size, out-of-plane deflections and low bias voltage. These requirements can be achieved with electrothermal actuators based on microelectromechanical systems (MEMS. We present the design and modeling of polysilicon electrothermal actuators for a MEMS mirror (100 μm × 100 μm × 2.25 μm. These actuators are composed by two beam types (2.25 μm thickness with different cross-section area, which are separated by 2 μm gap. The mirror and actuators are designed through the Sandia Ultra-planar Multi-level MEMS Technology V (SUMMiT V® process, obtaining a small footprint size (1028 μm × 1028 µm for actuators of 550 µm length. The actuators have out-of-plane displacements caused by low dc voltages and without use material layers with distinct thermal expansion coefficients. The temperature behavior along the actuators is calculated through analytical models that include terms of heat energy generation, heat conduction and heat energy loss. The force method is used to predict the maximum out-of-plane displacements in the actuator tip as function of supplied voltage. Both analytical models, under steady-state conditions, employ the polysilicon resistivity as function of the temperature. The electrothermal-and structural behavior of the actuators is studied considering different beams dimensions (length and width and dc bias voltages from 0.5 to 2.5 V. For 2.5 V, the actuator of 550 µm length reaches a maximum temperature, displacement and electrical power of 115 °C, 10.3 µm and 6.3 mW, respectively. The designed actuation mechanism can be useful for MEMS mirrors of different sizes with potential application in endoscopic OCT systems that require low power consumption.

  11. Soft Pneumatic Bending Actuator with Integrated Carbon Nanotube Displacement Sensor

    Directory of Open Access Journals (Sweden)

    Tim Giffney


    Full Text Available The excellent compliance and large range of motion of soft actuators controlled by fluid pressure has lead to strong interest in applying devices of this type for biomimetic and human-robot interaction applications. However, in contrast to soft actuators fabricated from stretchable silicone materials, conventional technologies for position sensing are typically rigid or bulky and are not ideal for integration into soft robotic devices. Therefore, in order to facilitate the use of soft pneumatic actuators in applications where position sensing or closed loop control is required, a soft pneumatic bending actuator with an integrated carbon nanotube position sensor has been developed. The integrated carbon nanotube position sensor presented in this work is flexible and well suited to measuring the large displacements frequently encountered in soft robotics. The sensor is produced by a simple soft lithography process during the fabrication of the soft pneumatic actuator, with a greater than 30% resistance change between the relaxed state and the maximum displacement position. It is anticipated that integrated resistive position sensors using a similar design will be useful in a wide range of soft robotic systems.

  12. A novel stiffness control method for series elastic actuator (United States)

    Lin, Guangmo; Zhao, Xingang; Han, Jianda


    Compliance plays an important role in human-robot cooperation. However, fixed compliance, or fixed stiffness, is difficult to meet the growing needs of human machine collaboration. As a result, the robot actuator is demanded to be able to adjust its stiffness. This paper presents a stiffness control scheme for a single DOF series elastic actuator (SEA) with a linear spring mounted in series in the mechanism. In this proposed method, the output angle of the spring is measured and used to calculate the input angle of the spring, thus the equivalent stiffness of the robot actuator revealed to the human operator can be rendered in accordance to the desired stiffness. Since the techniques used in this method only involve the position information of the system, there is no need to install an expensive force/torque sensor on the actuator. Further, the force/torque produced by the actuator can be estimated by simply multiplying the deformation angle of the spring and its constant stiffness coefficient. The analysis of the stiffness controller is provided. Then a simulation that emulates a human operates the SEA while the stiffness controller is running is carried out and the results also validate the proposed method.

  13. A novel compact compliant actuator design for rehabilitation robots. (United States)

    Yu, Haoyong; Huang, Sunan; Thakor, Nitish V; Chen, Gong; Toh, Siew-Lok; Sta Cruz, Manolo; Ghorbel, Yassine; Zhu, Chi


    Rehabilitation robots have direct physical interaction with human body. Ideally, actuators for rehabilitation robots should be compliant, force controllable, and back drivable due to safety and control considerations. Various designs of Series Elastic Actuators (SEA) have been developed for these applications. However, current SEA designs face a common performance limitation due to the compromise on the spring stiffness selection. This paper presents a novel compact compliant force control actuator design for portable rehabilitation robots to overcome the performance limitations in current SEAs. Our design consists of a servomotor, a ball screw, a torsional spring between the motor and the ball screw, and a set of translational springs between the ball screw nut and the external load. The soft translational springs are used to handle the low force operation and reduce output impedance, stiction, and external shock load. The torsional spring, being in the high speed range, has high effective stiffness and improves the system bandwidth in large force operation when the translational springs are fully compressed. This design is also more compact due to the smaller size of the springs. We explain the construction and the working principle of our new design, followed by the dynamic modeling and analysis of the actuator. We also show the preliminary testing results of a prototype actuator designed for a lower limb exoskeleton for gait rehabilitation.

  14. Placement optimization of actuators and sensors for gyroelastic body

    Directory of Open Access Journals (Sweden)

    Quan Hu


    Full Text Available Gyroelastic body refers to a flexible structure with a distribution of stored angular momentum provided by fly wheels or control moment gyroscopes. The angular momentum devices can exert active torques to the structure for vibration suppression or shape control. This article mainly focuses on the placement optimization issue of the actuators and sensors on the gyroelastic body. The control moment gyroscopes and angular rate sensors are adopted as actuators and sensors, respectively. The equations of motion of the gyroelastic body incorporating the detailed actuator dynamics are linearized to a loosely coupled state-space model. Two optimization approaches are developed for both constrained and unconstrained gyroelastic bodies. The first is based on the controllability and observability matrices of the system. It is only applicable to the collocated actuator and sensor pairs. The second criterion is formulated from the concept of controllable and observable subspaces. It is capable of handling the cases of both collocated and noncollocated actuator and sensor pairs. The illustrative examples of a cantilevered beam and an unconstrained plate demonstrate the clear physical meaning and rationality of the two proposed methods.

  15. Bioengineered novel robotic actuators for utilization in neuromuscular control (United States)

    Paul, Eddie


    A linear motion-controlling or power-actuating cylinder can be found in virtually all types of machinery. In many applications, however, limitations in performance of longevity of operation exist due to a number of factors ranging from nature's environmental extremes to the demands of complex design and engineering requirements. Industry has come to accept the limited flexibility of current power- and motion-regulating mechanisms such as hydraulic valve-controlled actuators, and oftentimes chooses to design around the inherent flaws and drawbacks of these basic components. As a result, the level of maintenance and potential for mechanical failure are greater than necessary in many applications from routine road construction where hydraulic machinery is instrumental, to undersea operations where man relies heavily on hydraulic-cylinder devices during most scientific, geographic and biological research excursions. With ultimate flexibility and environmental adaptability providing the key motivation, E. P. Industries, Inc. has developed and prototyped a system of Novel Robotic Actuators to function where operational or environmental demands exceed the capabilities of conventional hydraulic-valve devices. The objective in developing the Robotic Muscle is to replace a typical hydraulic cylinder actuator with a relatively more compact `muscle-like' actuator exhibiting maximum flexibility and a superior strength-to-weight ratio while resisting the harsh temperatures and deterioration factors presented by unusual operating environments. Progressive development of the Robotic Muscle will be directed to use as an artificial biological replacement.

  16. Dynamic modeling of brushless dc motors for aerospace actuation (United States)

    Demerdash, N. A.; Nehl, T. W.


    A discrete time model for simulation of the dynamics of samarium cobalt-type permanent magnet brushless dc machines is presented. The simulation model includes modeling of the interaction between these machines and their attached power conditioners. These are transistorized conditioner units. This model is part of an overall discrete-time analysis of the dynamic performance of electromechanical actuators, which was conducted as part of prototype development of such actuators studied and built for NASA-Johnson Space Center as a prospective alternative to hydraulic actuators presently used in shuttle orbiter applications. The resulting numerical simulations of the various machine and power conditioner current and voltage waveforms gave excellent correlation to the actual waveforms collected from actual hardware experimental testing. These results, numerical and experimental, are presented here for machine motoring, regeneration and dynamic braking modes. Application of the resulting model to the determination of machine current and torque profiles during closed-loop actuator operation were also analyzed and the results are given here. These results are given in light of an overall view of the actuator system components. The applicability of this method of analysis to design optimization and trouble-shooting in such prototype development is also discussed in light of the results at hand.

  17. Robot Arm with Tendon Connector Plate and Linear Actuator (United States)

    Ihrke, Chris A. (Inventor); Diftler, Myron A. (Inventor); Bridgwater, Lyndon (Inventor); Nguyen, Vienny (Inventor); Millerman, Alexander (Inventor)


    A robotic system includes a tendon-driven end effector, a linear actuator, a flexible tendon, and a plate assembly. The linear actuator assembly has a servo motor and a drive mechanism, the latter of which translates linearly with respect to a drive axis of the servo motor in response to output torque from the servo motor. The tendon connects to the end effector and drive mechanism. The plate assembly is disposed between the linear actuator assembly and the tendon-driven end effector and includes first and second plates. The first plate has a first side that defines a boss with a center opening. The second plate defines an accurate through-slot having tendon guide channels. The first plate defines a through passage for the tendon between the center opening and a second side of the first plate. A looped end of the flexible tendon is received within the tendon guide channels.

  18. Remote actuated valve implant (United States)

    McKnight, Timothy E; Johnson, Anthony; Moise, Jr., Kenneth J; Ericson, Milton Nance; Baba, Justin S; Wilgen, John B; Evans, III, Boyd McCutchen


    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  19. Remote actuated valve implant

    Energy Technology Data Exchange (ETDEWEB)

    McKnight, Timothy E.; Johnson, Anthony; Moise, Kenneth J.; Ericson, Milton Nance; Baba, Justin S.; Wilgen, John B.; Evans, Boyd Mccutchen


    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  20. Rigid-flexible coupling dynamic modeling and investigation of a redundantly actuated parallel manipulator with multiple actuation modes (United States)

    Liang, Dong; Song, Yimin; Sun, Tao; Jin, Xueying


    A systematic dynamic modeling methodology is presented to develop the rigid-flexible coupling dynamic model (RFDM) of an emerging flexible parallel manipulator with multiple actuation modes. By virtue of assumed mode method, the general dynamic model of an arbitrary flexible body with any number of lumped parameters is derived in an explicit closed form, which possesses the modular characteristic. Then the completely dynamic model of system is formulated based on the flexible multi-body dynamics (FMD) theory and the augmented Lagrangian multipliers method. An approach of combining the Udwadia-Kalaba formulation with the hybrid TR-BDF2 numerical algorithm is proposed to address the nonlinear RFDM. Two simulation cases are performed to investigate the dynamic performance of the manipulator with different actuation modes. The results indicate that the redundant actuation modes can effectively attenuate vibration and guarantee higher dynamic performance compared to the traditional non-redundant actuation modes. Finally, a virtual prototype model is developed to demonstrate the validity of the presented RFDM. The systematic methodology proposed in this study can be conveniently extended for the dynamic modeling and controller design of other planar flexible parallel manipulators, especially the emerging ones with multiple actuation modes.

  1. Active Vibration Control of a Flexible Structure Using Piezoceramic Actuators

    Directory of Open Access Journals (Sweden)

    J. Fei


    Full Text Available Considerable attention has been devoted recently to active vibration control using intelligent materials as actuators. This paper presents results on active control schemes for vibration suppression of flexible steel cantilever beam with bonded piezoelectric actuators. The PZT patches are surface bonded near the fixed end of flexible steel cantilever beam. The dynamic model of the flexible steel cantilever beam is derived. Active vibration control methods, strain rate feedback control (SRF, positive position feedback control (PPF are investigated and implemented using xPC Target real-time system. Experimental results demonstrate that the SRF control and PPF control achieve effective vibration suppression results of steel cantilever beam.

  2. Design and development of multi-lane smart electromechanical actuators

    CERN Document Server

    Annaz, Fawaz Yahya


    Design and Development of Multi-Lane Smart Electromechanical Actuators presents the design of electromechanical actuators in two types of architectures, namely, Torque Summed Architecture (TSA) and Velocity Summed Architecture, (VSA). It examines them in: * Hardware redundancy, where the architecture is made up of 3 or 4 lanes. * Digital Math Model redundancy, where a more compact two lanes architectures will be presented. The book starts with the very basic concepts and introduces the design process logically so that an understanding of the smart multi-lane systems that drive an aileron

  3. Devising Mobile Sensing and Actuation Infrastructure with Drones. (United States)

    Bae, Mungyu; Yoo, Seungho; Jung, Jongtack; Park, Seongjoon; Kim, Kangho; Kim, Joon Yeop Lee; Kim, Hwangnam


    Vast applications and services have been enabled as the number of mobile or sensing devices with communication capabilities has grown. However, managing the devices, integrating networks or combining services across different networks has become a new problem since each network is not directly connected via back-end core networks or servers. The issue is and has been discussed especially in wireless sensor and actuator networks (WSAN). In such systems, sensors and actuators are tightly coupled, so when an independent WSAN needs to collaborate with other networks, it is difficult to adequately combine them into an integrated infrastructure. In this paper, we propose drone-as-a-gateway (DaaG), which uses drones as mobile gateways to interconnect isolated networks or combine independent services. Our system contains features that focus on the service being provided in the order of importance, different from an adaptive simple mobile sink system or delay-tolerant system. Our simulation results have shown that the proposed system is able to activate actuators in the order of importance of the service, which uses separate sensors' data, and it consumes almost the same time in comparison with other path-planning algorithms. Moreover, we have implemented DaaG and presented results in a field test to show that it can enable large-scale on-demand deployment of sensing and actuation infrastructure or the Internet of Things (IoT).

  4. Study on core free rolled actuator based on soft dielectric EAP (United States)

    Kovacs, Gabor; Ha, Soon Mok; Michel, Silvain; Pelrine, Ron; Pei, Qibing


    The rolled actuator represents a design where the pre-stretched EAP film is wrapped many times around a spring core in order to form a multilayer actuator system with unidirectional actuation. The freestanding rolled configuration enables the use of the DE film for muscle like linear actuators with a broad application potential. The stress state of the pre-strained acrylic film in the rolled configuration and the required stiff core can cause several serious problems concerning lifetime, size and efficiency of the actuator. In order to obtain an acceptable specific actuator performance and lifetime the pre-stretching stress has to be essentially reduced or even eliminated. This can be achieved by the interpenetrating polymer network (IPN) process newly developed at the UCLA. Thereby a trifunctional methacrylate monomers is introduced into the highly pre-strained acrylic films and subsequently curing the monomers to form an interpenetrating elastomeric network. The as obtained interpenetrating polymer network (IPN) can effectively support the pre-strain of the acrylic film and consequently eliminate the need for external pre-strain-supporting structures. In this study a new rolled actuator design is presented based on the IPN post treated VHB material. Due to the stress free state of the wrapped film no spring core is necessary. As a result a significantly longer lifetime and better specific volume efficiency of the actuator has been achieved at lower unidirectional elongation when activated. Introductorily, the specific problems on conventional rolled actuators are discussed and the aims for core free rolled actuators are specified. Then some structural design parameters are addressed in order to achieve a slight shape and reliable working principle. In the main part of the study the manufacturing process of the actuators and some measurement results and experiences are discussed in detail.

  5. Computed torque control of an under-actuated service robot platform modeled by natural coordinates (United States)

    Zelei, Ambrus; Kovács, László L.; Stépán, Gábor


    The paper investigates the motion planning of a suspended service robot platform equipped with ducted fan actuators. The platform consists of an RRT robot and a cable suspended swinging actuator that form a subsequent parallel kinematic chain and it is equipped with ducted fan actuators. In spite of the complementary ducted fan actuators, the system is under-actuated. The method of computed torques is applied to control the motion of the robot. The under-actuated systems have less control inputs than degrees of freedom. We assume that the investigated under-actuated system has desired outputs of the same number as inputs. In spite of the fact that the inverse dynamical calculation leads to the solution of a system of differential-algebraic equations (DAE), the desired control inputs can be determined uniquely by the method of computed torques. We use natural (Cartesian) coordinates to describe the configuration of the robot, while a set of algebraic equations represents the geometric constraints. In this modeling approach the mathematical model of the dynamical system itself is also a DAE. The paper discusses the inverse dynamics problem of the complex hybrid robotic system. The results include the desired actuator forces as well as the nominal coordinates corresponding to the desired motion of the carried payload. The method of computed torque control with a PD controller is applied to under-actuated systems described by natural coordinates, while the inverse dynamics is solved via the backward Euler discretization of the DAE system for which a general formalism is proposed. The results are compared with the closed form results obtained by simplified models of the system. Numerical simulation and experiments demonstrate the applicability of the presented concepts.

  6. Velocity feedback control with a flywheel proof mass actuator (United States)

    Kras, Aleksander; Gardonio, Paolo


    This paper presents four new proof mass actuators to be used in velocity feedback control systems for the control of vibrations of machines and flexible structures. A classical proof mass actuator is formed by a coil-magnet linear motor, with either the magnet or the armature-coil proof mass suspended on soft springs. This arrangement produces a net force effect at frequencies above the fundamental resonance frequency of the springs-proof mass system. Thus, it can be used to implement point velocity feedback loops, although the dynamic response and static deflection of the springs-proof mass system poses some stability and control performance limitations. The four proof mass actuators presented in this study include a flywheel element, which is used to augment the inertia effect of the suspended proof mass. The paper shows that the flywheel element modifies both the dynamic response and static deflection of the springs-proof mass system in such a way as the stability and control performance of velocity feedback loops using these actuators are significantly improved.

  7. Electrical actuators applications and performance

    CERN Document Server

    De Fornel, Bernard


    This helpful resource covers a large range of information regarding electrical actuators. In particular, robustness, a very problematic issue, is fully explored in a dedicated chapter. The text also deals with he estimate of non-measurable mechanical variables by examining the estimate of load moment, then observation of the positioning of a command without mechanical sensor. Finally, it examines the conditions needed to measure variables and real implementation of numerical algorithms. This is a key working resource for electrical engineers.

  8. An Innovative Shape Memory Actuator

    Directory of Open Access Journals (Sweden)

    Cappellini Valter


    Full Text Available The work describes a NiTi linear actuator. This material is able to realize a contraction with heating produced through Joule effect. Then a cooling of the active device is realized with forced air. Finally the lengthening is realized with another active element. The particular structure of the geometry allows for an increment of reliability, because the electrical connections are mechanically stabilized and the active elements are compelled to avoid undesired electrical contacts through an insulated cylindrical core.

  9. Pneumatic artificial muscle actuators for compliant robotic manipulators (United States)

    Robinson, Ryan Michael

    Robotic systems are increasingly being utilized in applications that require interaction with humans. In order to enable safe physical human-robot interaction, light weight and compliant manipulation are desirable. These requirements are problematic for many conventional actuation systems, which are often heavy, and typically use high stiffness to achieve high performance, leading to large impact forces upon collision. However, pneumatic artificial muscles (PAMs) are actuators that can satisfy these safety requirements while offering power-to-weight ratios comparable to those of conventional actuators. PAMs are extremely lightweight actuators that produce force in response to pressurization. These muscles demonstrate natural compliance, but have a nonlinear force-contraction profile that complicates modeling and control. This body of research presents solutions to the challenges associated with the implementation of PAMs as actuators in robotic manipulators, particularly with regard to modeling, design, and control. An existing PAM force balance model was modified to incorporate elliptic end geometry and a hyper-elastic constitutive relationship, dramatically improving predictions of PAM behavior at high contraction. Utilizing this improved model, two proof-of-concept PAM-driven manipulators were designed and constructed; design features included parallel placement of actuators and a tendon-link joint design. Genetic algorithm search heuristics were employed to determine an optimal joint geometry; allowing a manipulator to achieve a desired torque profile while minimizing the required PAM pressure. Performance of the manipulators was evaluated in both simulation and experiment employing various linear and nonlinear control strategies. These included output feedback techniques, such as proportional-integral-derivative (PID) and fuzzy logic, a model-based control for computed torque, and more advanced controllers, such as sliding mode, adaptive sliding mode, and

  10. Electrostatic comb drive for vertical actuation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A. P., LLNL


    The electrostatic comb finger drive has become an integral design for microsensor and microactuator applications. This paper reports on utilizing the levitation effect of comb fingers to design vertical-to-the-substrate actuation for interferometric applications. For typical polysilicon comb drives with 2 {micro}m gaps between the stationary and moving fingers, as well as between the microstructures and the substrate, the equilibrium position is nominally 1-2 {micro}m above the stationary comb fingers. This distance is ideal for many phase shifting interferometric applications. Theoretical calculations of the vertical actuation characteristics are compared with the experimental results, and a general design guideline is derived from these results. The suspension flexure stiffnesses, gravity forces, squeeze film damping, and comb finger thicknesses are parameters investigated which affect the displacement curve of the vertical microactuator. By designing a parallel plate capacitor between the suspended mass and the substrate, in situ position sensing can be used to control the vertical movement, providing a total feedback-controlled system. Fundamentals of various capacitive position sensing techniques are discussed. Experimental verification is carried out by a Zygo distance measurement interferometer.

  11. Numerical analysis of helical dielectric elastomer actuator (United States)

    Park, Jang Ho; Nair, Saurabh; Kim, Daewon


    Dielectric elastomer actuators (DEA) are known for its capability of experiencing extreme strains, as it can expand and contract based on specific actuation voltage applied. On contrary, helical DEA (HDEA) with its unique configuration does not only provide the contractile and extendable capabilities, but also can aid in attaining results for bending and torsion. The concept of HDEA embraces many new techniques and can be applied in multiple disciplines. Thus, this paper focuses on the simulation of HDEA with helical compliant electrodes that is a major factor prior to its application. The attributes of the material used to build the structure plays a vital role in the behavior of the system. For numerical analysis of HDEA, the material characteristics are input into a commercial grade software, and then the appropriate analysis is performed to retrieve its outcome. Applying the material characteristics into numerical analysis modeling, the functionality of HDEA for various activations can be achieved, which is used to test and comply with the fabricated final product.

  12. Experimental characterization of piezoelectric THUNDER actuator shape (United States)

    Harris, Paul


    A new type of piezoelectric composite actuator called THUNDER, which was originally developed by NASA, has potential applications in micro robotics, aeronautics, acoustics and hydraulics. The manufacturing process produces internal stresses with accompanying structural deformation. It is the aim of this research to characterize these deformations. Detailed measurements were taken by a motion control LabView data acquisition system and measured with a laser micrometer on several different types of actuators. Several functional forms were used in an attempt to fit the data. The data was best fit by a circular segment function. We also used a transcendental equation to be able to compare to other single point published values. We found the range of dome heights to be between 10.15 mm and 1.45 mm. For one particular model, the manufacturing difference was found to be 16% with an experimental error of 0.5%. The robust experimental data is vital to the development of our finite elements models. Preliminary experimental results of voltage induced deformations will be presented.

  13. Electric actuator for the sempell gate valve

    Energy Technology Data Exchange (ETDEWEB)

    Herbstritt, E.C.


    The automation of valves has a primary importance in the scope of central control and regulation of power generation processes in power plants and especially in nuclear power plants. AUMA WERNER RIESTER GmbH & Co. KG is considered a leading manufacturer of electric actuators for the automation of valves. More than 30 years experience in designing, developing, and manufacturing provide a sound basis for offering reliable products, especially for nuclear applications. The quality assurance system of AUMA was developed according to 10 CFR 50, Appendix B and has been consistently accomplished. The program was certified by the TUV Germany (Technical Authorized Inspection Agency), according to ISO-9001, in 1994. AUMA offers two actuator type ranges for application in nuclear power plants. The range SAI is qualified according to IEEE 382-1978 and is designed for inside containment. The range SAN is qualified according to IEEE 382-1985 and KTA 3504-1988 for use in non-radioactive applications in the nuclear power plants.

  14. Variable sweep geometry primary structure actuation (United States)

    Knowles, Gareth J.; Bird, Ross W.; White, Edward V.; Valentino, Michael


    Several corporations including QorTek and Boeing have both independently proposed variable sweep primary structures for future adaptive airframe structures as to enable miniaturized area dominance munitions and UAVs. Various new vehicle concepts must insert a high power actuator to overcome low speed aerodynamic forces within a limited packaging availability. In order to meet requirements for this and other UAV/UCAV/MMT missions, require a re-thinking on how to accomplish large motor torque/lb (rather than energy/lb) while integrating the speed and torque capability in a small package. The difficulty is highlighted by considering that piezo devices are nicely compact but can only deliver is typically 1-2ft-lb/lb; whereas SMA has potential of being lighter solution and can deliver 100-200 ft-lb/lb but has two problems: slow recovery and large weight penalty for thermal components. Fortunately, some munition applications have relatively modest control surface actuation bandwidth requirements. However, until now, the thermal aspect has been prohibitive. QorTek will present a new SMA-based motor that provides high torque/lb for UAV/UCAV/MMT systems. This unique motor design has eliminated the need for additional power components for thermal excitation (transient heating) of the SMA elements as to accomplish phase transition. The resulting package is the desirable lightweight and compact packaged solution to many air vehicle and munition needs. Moreover, the design eliminates the undesirable "snapping" action associated with SMA phase transition.

  15. Application of polyimide actuator rod seals (United States)

    Watermann, A. W.; Gay, B. F.; Robinson, E. D.; Srinath, S. K.; Nelson, W. G.


    Development of polyimide two-stage hydraulic actuator rod seals for application in high-performance aircraft was accomplished. The significant portion of the effort was concentrated on optimization of the chevron and K-section second-stage seal geometries to satisfy the requirements for operation at 450 K (350 F) with dynamic pressure loads varying between 200 psig steady-state and 1500 psig impulse cycling. Particular significance was placed on reducing seal gland dimension by efficiently utilizing the fatigue allowables of polyimide materials. Other objectives included investigation of pressure balancing techniques for first-stage polyimide rod seals for 4000 psig 450 K(350 F) environment and fabrication of a modular retainer for the two-stage combination. Seals were fabricated in 0.0254 m (1.0in.) and 0.0635 m (2.5in.) sizes and tested for structural integrity, frictional resistance, and endurance life. Test results showed that carefully designed second stages using polyimides could be made to satisfy the dynamic return pressure requirements of applications in high-performance aircraft. High wear under full system pressure indicated that further research is necessary to obtain an acceptable first-stage design. The modular retainer was successfully tested and showed potential for new actuator applications.

  16. A General Contact Force Analysis of an Under-Actuated Finger in Robot Hand Grasping

    Directory of Open Access Journals (Sweden)

    Xuan Vinh Ha


    Full Text Available This paper develops a mathematical analysis of contact forces for the under-actuated finger in a general under-actuated robotic hand during grasping. The concept of under-actuation in robotic grasping with fewer actuators than degrees of freedom (DOF, through the use of springs and mechanical limits, allows the hand to adjust itself to an irregularly shaped object without complex control strategies and sensors. Here the main concern is the contact forces, which are important elements in grasping tasks, based on the proposed mathematical analysis of their distributions of the n-DOF under-actuated finger. The simulation results, along with the 3-DOF finger from the ADAMS model, show the effectiveness of the mathematical analysis method, while comparing them with the measured results. The system can find magnitudes of the contact forces at the contact positions between the phalanges and the object.

  17. Multi-Mode Electric Actuator Dynamic Modelling for Missile Fin Control

    Directory of Open Access Journals (Sweden)

    Bhimashankar Gurav


    Full Text Available Linear first/second order fin direct current (DC actuator model approximations for missile applications are currently limited to angular position and angular velocity state variables. Furthermore, existing literature with detailed DC motor models is decoupled from the application of interest: tail controller missile lateral acceleration (LATAX performance. This paper aims to integrate a generic DC fin actuator model with dual-mode feedforward and feedback control for tail-controlled missiles in conjunction with the autopilot system design. Moreover, the characteristics of the actuator torque information in relation to the aerodynamic fin loading for given missile trim velocities are also provided. The novelty of this paper is the integration of the missile LATAX autopilot states and actuator states including the motor torque, position and angular velocity. The advantage of such an approach is the parametric analysis and suitability of the fin actuator in relation to the missile lateral acceleration dynamic behaviour.

  18. Static deflection control of flexible beams by piezo-electric actuators (United States)

    Baz, A. M.


    This study deals with the utilization of piezo-electric actuators in controlling the static deformation of flexible beams. An optimum design procedure is presented to enable the selection of the optimal location, thickness and excitation voltage of the piezo-electric actuators in a way that would minimize the deflection of the beam to which these actuators are bonded. Numerical examples are presented to illustrate the application of the developed optimization procedure in minimizing the structural deformation of beams of different materials when subjected to different loading and end conditions using ceramic or polymeric piezo-electric actuators. The results obtained emphasize the importance of the devised rational procedure in designing beam-actuator systems with minimal elastic distortions.

  19. Low-Actuation Voltage MEMS Digital-to-Analog Converter with Parylene Spring Structures. (United States)

    Ma, Cheng-Wen; Lee, Fu-Wei; Liao, Hsin-Hung; Kuo, Wen-Cheng; Yang, Yao-Joe


    We propose an electrostatically-actuated microelectromechanical digital-to-analog converter (M-DAC) device with low actuation voltage. The spring structures of the silicon-based M-DAC device were monolithically fabricated using parylene-C. Because the Young's modulus of parylene-C is considerably lower than that of silicon, the electrostatic microactuators in the proposed device require much lower actuation voltages. The actuation voltage of the proposed M-DAC device is approximately 6 V, which is less than one half of the actuation voltages of a previously reported M-DAC equipped with electrostatic microactuators. The measured total displacement of the proposed three-bit M-DAC is nearly 504 nm, and the motion step is approximately 72 nm. Furthermore, we demonstrated that the M-DAC can be employed as a mirror platform with discrete displacement output for a noncontact surface profiling system.

  20. Low-Actuation Voltage MEMS Digital-to-Analog Converter with Parylene Spring Structures

    Directory of Open Access Journals (Sweden)

    Cheng-Wen Ma


    Full Text Available We propose an electrostatically-actuated microelectromechanical digital-to-analog converter (M-DAC device with low actuation voltage. The spring structures of the silicon-based M-DAC device were monolithically fabricated using parylene-C. Because the Young’s modulus of parylene-C is considerably lower than that of silicon, the electrostatic microactuators in the proposed device require much lower actuation voltages. The actuation voltage of the proposed M-DAC device is approximately 6 V, which is less than one half of the actuation voltages of a previously reported M-DAC equipped with electrostatic microactuators. The measured total displacement of the proposed three-bit M-DAC is nearly 504 nm, and the motion step is approximately 72 nm. Furthermore, we demonstrated that the M-DAC can be employed as a mirror platform with discrete displacement output for a noncontact surface profiling system.

  1. Stress compensation for arbitrary curvature control in vanadium dioxide phase transition actuators

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Kaichen, E-mail:, E-mail: [Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084 (China); Lou, Shuai; Choe, Hwan Sung; Yao, Jie; Wu, Junqiao, E-mail:, E-mail: [Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Liu, Kai [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); You, Zheng [State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing 100084 (China)


    Due to its thermally driven structural phase transition, vanadium dioxide (VO{sub 2}) has emerged as a promising material for micro/nano-actuators with superior volumetric work density, actuation amplitude, and repetition frequency. However, the high initial curvature of VO{sub 2} actuators severely obstructs the actuation performance and application. Here, we introduce a “seesaw” method of fabricating tri-layer cantilevers to compensate for the residual stress and realize nearly arbitrary curvature control of VO{sub 2} actuators. By simply adjusting the thicknesses of the individual layers, cantilevers with positive, zero, or negative curvatures can be engineered. The actuation amplitude can be decoupled from the curvature and controlled independently as well. Based on the experimentally measured residual stresses, we demonstrate sub-micron thick VO{sub 2} actuators with nearly zero final curvature and a high actuation amplitude simultaneously. This “seesaw” method can be further extended to the curvature engineering of other microelectromechanical system multi-layer structures where large stress-mismatch between layers are inevitable.

  2. Development of a piezoelectric induced-strain actuator with an innovative internal amplifying structure (United States)

    Yung, Chung Sheung; Or, Siu Wing; Chan, Helen Lai Wa; Choy, Ping Kong; Liu, Peter Chou Kee


    The development of a novel piezoelectric induced-strain actuator possessing an innovative internal amplifying structure is presented in this paper. This actuator basically consists of a metal frame and two lead zirconate titanate (PZT) piezoelectric ceramic patches. The metal frame is bent to form an open trapezoid, where its center part has a specially designed saddle-like unit and its slanting legs are attached with PZT patches. The saddle-like unit has an amplifying-lever mechanism at the corners to increase the displacement output of the whole actuator even its legs are mechanically clamped. When an electric field is applied across the thickness of the PZT patches, the patches induce deformations on the whole actuator through the piezoelectric d31 effect. The saddle-like unit can relax the constraints at the joints between the unit and the legs by stretching itself during bending. Piezoelectric finite element analysis is used to maximize the work output of displacement and blocked force of the actuator under different geometric parameters. The results are in good agreement with those obtained from quasi-static measurements, showing that the actuator has work output comparable to and larger than the existing induced-strain actuators (e.g., THUNDER) under fixed mounting conditions. Therefore, the actuator has great potential for use in various practical smart structures and integrated systems, including active-passive vibration isolation and micro-positioning.

  3. Antagonistic dielectric elastomer actuator for biologically-inspired robotics (United States)

    Conn, Andrew T.; Rossiter, Jonathan


    For optimal performance, actuators designed for biologically-inspired robotics applications need to be capable of mimicking the key characteristics of natural musculoskeletal systems. These characteristics include a large output stroke, high energy density, antagonistic operation and passive compliance. The actuation properties of dielectric elastomer actuators (DEAs) make them viable for use as an artificial muscle technology. However, much like the musculoskeletal system, rigid structures are needed to couple the compliant DEA layers to a load. In this paper, a cone DEA design is developed as an antagonistic, multi-DOF actuator, viable for a variety for biologically-inspired robotics applications. The design has the advantage of maintaining pre-strain through a support structure without substantially lowering the overall mass-specific power density. Prototype cone DEAs have been fabricated with VHB 4910 acrylic elastomer and have characteristic dimensions of 49mm (strut length) and 60mm (DEA diameter). Multi-DOF kinematical outputs of the cone DEAs were measured using a custom 3D motion tracking system. Experimental tests of the prototypes demonstrate antagonistic linear (+/-10mm), rotational (+/-25°) and combined multi-DOF strokes. Overall, antagonistic cone DEAs are shown to produce a complex multi-DOF output from a mass-efficient support structure and thus are well suited for being exploited in biologically-inspired robotics.

  4. In situ multi-dimensional actuation measurement method for tensile actuation of paraffin-infiltrated multi-wall carbon nanotube yarns (United States)

    Dang, Dang Xuan; Truong, Thuy Kieu; Lim, Seong Chu; Suh, Dongseok


    We introduce an experimental setup for the simultaneous measurement of axial and radial strain variations of a hybrid carbon nanotube (CNT) yarn actuator, where a paraffin wax is melt-infiltrated inside the CNT yarn. Such a hybrid yarn system has been known as a Joule-heating-driven tensile/torsional actuator due to a large volume expansion of the infiltrated paraffin upon a solid-to-liquid phase transition. During the operation of this actuator, however, the axial strain variations along the yarn axis and the diameter change of the yarn, which is the radial strain variations perpendicular to the yarn axis, had been measured separately, which prohibits the exact understanding of the whole actuation dynamics. In the new experimental configuration, a laser scan micrometer is employed for the in situ yarn's diameter measurement and is combined with the conventional tensile actuation measurement setup for real-time data-taking during the actuation. When the hybrid CNT yarn was tested, the synchronized strain variation data in the axial and radial directions were obtained, which helps the analysis of these actuation phenomena especially in the intermediate states.

  5. Space Shuttle Rudder Speed Brake Actuator-A Case Study Probabilistic Fatigue Life and Reliability Analysis (United States)

    Oswald, Fred B.; Savage, Michael; Zaretsky, Erwin V.


    The U.S. Space Shuttle fleet was originally intended to have a life of 100 flights for each vehicle, lasting over a 10-year period, with minimal scheduled maintenance or inspection. The first space shuttle flight was that of the Space Shuttle Columbia (OV-102), launched April 12, 1981. The disaster that destroyed Columbia occurred on its 28th flight, February 1, 2003, nearly 22 years after its first launch. In order to minimize risk of losing another Space Shuttle, a probabilistic life and reliability analysis was conducted for the Space Shuttle rudder/speed brake actuators to determine the number of flights the actuators could sustain. A life and reliability assessment of the actuator gears was performed in two stages: a contact stress fatigue model and a gear tooth bending fatigue model. For the contact stress analysis, the Lundberg-Palmgren bearing life theory was expanded to include gear-surface pitting for the actuator as a system. The mission spectrum of the Space Shuttle rudder/speed brake actuator was combined into equivalent effective hinge moment loads including an actuator input preload for the contact stress fatigue and tooth bending fatigue models. Gear system reliabilities are reported for both models and their combination. Reliability of the actuator bearings was analyzed separately, based on data provided by the actuator manufacturer. As a result of the analysis, the reliability of one half of a single actuator was calculated to be 98.6 percent for 12 flights. Accordingly, each actuator was subsequently limited to 12 flights before removal from service in the Space Shuttle.

  6. Plasma actuators for bluff body flow control (United States)

    Kozlov, Alexey V.

    The aerodynamic plasma actuators have shown to be efficient flow control devices in various applications. In this study the results of flow control experiments utilizing single dielectric barrier discharge plasma actuators to control flow separation and unsteady vortex shedding from a circular cylinder in cross-flow are reported. This work is motivated by the need to reduce landing gear noise for commercial transport aircraft via an effective streamlining created by the actuators. The experiments are performed at Re D = 20,000...164,000. Circular cylinders in cross-flow are chosen for study since they represent a generic flow geometry that is similar in all essential aspects to a landing gear oleo or strut. The minimization of the unsteady flow separation from the models and associated large-scale wake vorticity by using actuators reduces the radiated aerodynamic noise. Using either steady or unsteady actuation at ReD = 25,000, Karman shedding is totally eliminated, turbulence levels in the wake decrease significantly and near-field sound pressure levels are reduced by 13.3 dB. Unsteady actuation at an excitation frequency of St D = 1 is found to be most effective. The unsteady actuation also has the advantage that total suppression of shedding is achieved for a duty cycle of only 25%. However, since unsteady actuation is associated with an unsteady body force and produces a tone at the actuation frequency, steady actuation is more suitable for noise control applications. Two actuation strategies are used at ReD = 82,000: spanwise and streamwise oriented actuators. Near field microphone measurements in an anechoic wind tunnel and detailed study of the near wake using LDA are presented in the study. Both spanwise and streamwise actuators give nearly the same noise reduction level of 11.2 dB and 14.2 dB, respectively, and similar changes in the wake velocity profiles. The contribution of the actuator induced noise is found to be small compared to the natural shedding

  7. Thermal vertical bimorph actuators and their applications

    CERN Document Server

    Sehr, H J


    In this thesis, a novel concept for lateral actuators based on vertical bimorphs is presented. Vertical bimorphs consist of silicon beams side-coated with aluminium, which bend when heated due to the different thermal expansion coefficients of the two materials causing a displacement in the wafer plane. The heating of the actuator is provided by an electrical current through the silicon beam. The simplest implementation of a vertical bimorph actuator is a clamped-clamped beam. To obtain higher deflections, a meander shaped actuator has been designed. By combining four meander actuators, a two-dimensional positioning stage has been realised. The meander actuator has also been applied for normally closed and normally open micro-relays. Analytical calculations and ANSYS simulations have been carried out to predict the physical behaviour of the bimorph devices, including temperature distribution, static deflection, vertical stiffness, thermal time constant and lateral resonances. For both the clamped-clamped beam...

  8. Series Elastic Actuators for legged robots (United States)

    Pratt, Jerry E.; Krupp, Benjamin T.


    Series Elastic Actuators provide many benefits in force control of robots in unconstrained environments. These benefits include high force fidelity, extremely low impedance, low friction, and good force control bandwidth. Series Elastic Actuators employ a novel mechanical design architecture which goes against the common machine design principal of "stiffer is better." A compliant element is placed between the gear train and driven load to intentionally reduce the stiffness of the actuator. A position sensor measures the deflection, and the force output is accurately calculated using Hooke"s Law (F=Kx). A control loop then servos the actuator to the desired output force. The resulting actuator has inherent shock tolerance, high force fidelity and extremely low impedance. These characteristics are desirable in many applications including legged robots, exoskeletons for human performance amplification, robotic arms, haptic interfaces, and adaptive suspensions. We describe several variations of Series Elastic Actuators that have been developed using both electric and hydraulic components.

  9. Microwave Power for Smart Membrane Actuators (United States)

    Choi, Sang H.; Song, Kyo D.; Golembiewski, Walter T.; Chu, Sang-Hyon; King, Glen C.


    The concept of microwave-driven smart membrane actuators is envisioned as the best option to alleviate the complexity associated with hard-wired control circuitry. A large, ultra-light space structure, such as solar sails and Gossamer spacecrafts, requires a distribution of power into individual membrane actuators to control them in an effective way. A patch rectenna array with a high voltage output was developed to drive smart membrane actuators. Networked patch rectenna array receives and converts microwave power into a DC power for an array of smart actuators. To use microwave power effectively, the concept of a power allocation and distribution (PAD) circuit is developed and tested for networking a rectenna/actuator patch array. For the future development, the PAD circuit could be imbedded into a single embodiment of rectenna and actuator array with the thin-film microcircuit embodiment. Preliminary design and fabrication of PAD circuitry that consists of a sixteen nodal elements were made for laboratory testing.

  10. Design of shape memory alloy (SMA) actuators

    CERN Document Server

    Rao, Ashwin; Reddy, J N


    This short monograph presents an analysis and design methodology for shape memory alloy (SMA) components such as wires, beams, and springs for different applications. The solid-solid, diffusionless phase transformations in thermally responsive SMA allows them to demonstrate unique characteristics like superelasticity and shape memory effects. The combined sensing and actuating capabilities of such materials allows them to provide a system level response by combining multiple functions in a single material system. In SMA, the combined mechanical and thermal loading effects influence the functionality of such materials. The aim of this book is to make the analysis of these materials accessible to designers by developing a "strength of materials" approach to the analysis and design of such SMA components inspired from their various applications with a review of various factors influencing the design process for such materials.

  11. Relaxed formulation of the design conditions for Takagi-Sugeno fuzzy virtual actuators

    Directory of Open Access Journals (Sweden)

    Filasová Anna


    Full Text Available The H∞ norm approach to virtual actuators design, intended to Takagi-Sugeno fuzzy continuous-time systems, is presented in the paper. Using the second Ljapunov method, the design conditions are formulated in terms of linear matrix inequalities in adapted bounded real lemma structures. Related to the static output controller, and for systems under influence of single actuator faults, the design steps are revealed for a three-tank system plant.

  12. Stimuli-Responsive Polymers for Actuation. (United States)

    Zhang, Qiang Matthew; Serpe, Michael J


    A variety of stimuli-responsive polymers have been developed and used as actuators and/or artificial muscles, with the movement being driven by an external stimulus, such as electrical potential. This Review highlights actuators constructed from liquid-crystal elastomers, dielectric elastomers, ionic polymers, and conducting polymers. The Review covers recent examples of a variety of actuators generated from these materials and their utility. The mechanism of actuation will be detailed for most examples in order to stimulate possible future research, and lead to new applications and advanced applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. High Reliability Cryogenic Piezoelectric Valve Actuator Project (United States)

    National Aeronautics and Space Administration — Cryogenic fluid valves are subject to harsh exposure and actuators to drive these valves require robust performance and high reliability. DSM's piezoelectric...

  14. Dynamic Hybrid Materials: Hydrogel Actuators and Catalytic Microsystems (United States)

    Zarzar, Lauren Dell

    Dynamic materials which can sense changes in their surroundings and subsequently respond or adapt by autonomously altering their functionality, surface chemistry, transparency, color, wetting behavior, adhesiveness, shape, etc. are primed to be integral components of future "smart" technologies. However, such systems can be quite complex and often require intricate coordination between both chemical and mechanical inputs/outputs as well as the combination of multiple materials working cooperatively to achieve the proper functionality. It is critical to not only understand the fundamental behaviors of existing dynamic chemo-mechanical systems, but also to apply that knowledge and explore new avenues for design of novel materials platforms which could provide a basis for future adaptive technologies. Part 1 explores the use of environmentally-sensitive hydrogels, either alone or within arrays of high-aspect-ratio nano/microstructures, as chemo-mechanical actuators. Chapters 1 through 7 describe a bio-inspired approach to the design of hybrid actuating surfaces in which the volume-changing hydrogel acts as the "muscle" that reversibly actuates the microstructured "bone". In particular, the different actuation mechanisms arising from variations in how the hydrogel is integrated into the structure array, how chemical signals can be used to manipulate actuation parameters, and finally how such a system may be used for applications ranging from adaptive optics to manipulation of chemical reactions are described. Chapter 8 discusses the use of responsive hydrogel scaffolds as a means to mechanically compress cells and direct differentiation. Part II explores dynamic microsystems involving the integration of catalytic sites within intricately structured 3D microenvironments. Specifically, we explore a generalizable and straightforward route to fabricate microscale patterns of nanocrystalline platinum and palladium using multiphoton lithography. The catalytic, electrical

  15. Enhancement of Optical Adaptive Sensing by Using a Dual-Stage Seesaw-Swivel Actuator with a Tunable Vibration Absorber

    Directory of Open Access Journals (Sweden)

    Po-Chien Chou


    Full Text Available Technological obstacles to the use of rotary-type swing arm actuators to actuate optical pickup modules in small-form-factor (SFF disk drives stem from a hinge’s skewed actuation, subsequently inducing off-axis aberrations and deteriorating optical quality. This work describes a dual-stage seesaw-swivel actuator for optical pickup actuation. A triple-layered bimorph bender made of piezoelectric materials (PZTs is connected to the suspension of the pickup head, while the tunable vibration absorber (TVA unit is mounted on the seesaw swing arm to offer a balanced force to reduce vibrations in a focusing direction. Both PZT and TVA are designed to satisfy stable focusing operation operational requirements and compensate for the tilt angle or deformation of a disc. Finally, simulation results verify the performance of the dual-stage seesaw-swivel actuator, along with experimental procedures and parametric design optimization confirming the effectiveness of the proposed system.

  16. Highly durable, biomimetic electro-active paper actuator based on cellulose polypyrrole-ionic liquid (CPIL) nanocomposite. (United States)

    Mahadeva, Suresha K; Yun, Kiju; Kim, Jaehwan; Kim, Joo-Hyung


    Cellulose has received much attention as a emerging smart material, named as electro-active paper (EAPap), which can produce a large bending displacement with applied external electrical field. In spite of many advantages over other reported electro active polymers, there are some issues to be addressed: its actuator performance: (i) sensitive to environmental humidity, (ii) humidity dependent displacement output of the actuator and (iii) degradation of performance with time. In present paper, we have successfully developed the highly durable EAPap actuator working at ambient condition with large displacement output. To improve the performance and durability of EAPap, nanoscaled PPy layer into cellulose EAPap was formed by in-situ polymerization technique. Cellulose-PPy-IL nanocomposite based EAPap actuator showed nearly 100% improvement of the actuator performance compared that of pure cellulose based EAPap actuator systems.

  17. Electroactive polymers as a novel actuator technology for lighter-than-air vehicles (United States)

    Michel, Silvain; Dürager, Christian; Zobel, Martin; Fink, Erich


    In this paper the worldwide first EAP actuated blimp will be presented. It consists of a slightly pressurized Helium filled body of a biologically inspired form with Dielectric Elastomer (DE) actuators driving a classical cross tail with two vertical and horizontal rudders for flight control. Two versions of actuators will be discussed: The first version consisted of "spring-roll" type of cylindrical actuators placed together with the electrical supply and control unit in the pay load gondola. The second version consisted of a configuration, where the actuators are placed between the control surfaces and the rudders. This novel type of EAP actuator named "active hinge" was developed and characterized first in the laboratory and afterwards optimized for minimum weight and finally integrated in the blimp structure. In the design phase a numerical simulation tool for the prediction of the DE actuators was developed based on a material model calibrated with the test results from cylindrical actuators. The electrical supply and control system was developed and optimized for minimum of weight. Special attention was paid to the electromagnetic systems compatibility of the high voltage electrical supply system of the DE actuators and the radio flight control system. The design and production of this 3.5 meter long Lighter-than-Air vehicle was collaboration between Empa Duebendorf Switzerland and the Technical University of Berlin. The first version of this EAP blimp first flew at an RC airship regatta hold on 24 th of June 2006 in Dresden Germany, while the second version had his maiden flight on 8 th of January 2007 in Duebendorf Switzerland. In both cases satisfactory flight control performances were demonstrated.

  18. The installation of a sub sea floor observatory using the sea floor drill rig MeBo (United States)

    Wefer, G.; Freudenthal, T.; Kopf, A.


    Sea floor drill rigs that can be deployed from standard research vessels are bridging the gap between dedicated drill ships that are used for deep drillings in the range of several hundred meters below sea floor and conventional sampling tools like gravity corers, piston corer or dredges that only scratch the surface of the sea floor. A major advantage of such robotic drill rigs is that the drilling action is conducted from a stable platform at the sea bed independent of any ship movements due to waves, wind or currents. At the MARUM Center for Marine Environmental Sciences at the University of Bremen we developed the sea bed drill rig MeBo that can be deployed from standard research vessels. The drill rig is deployed on the sea floor and controlled from the vessel. Drilling tools for coring the sea floor down to 70 m can be stored on two magazines on the rig. A steel-armoured umbilical is used for lowering the rig to the sea bed in water depths up to 2000 m in the present system configuration. It was successfully operated on ten expeditions since 2005 and drilled more than 1000 m in different types of geology including hemipelagic mud, glacial till as well as sedimentary and crystalline rocks. MeBo boreholes be equipped with sensors and used for long term monitoring are planned. Depending on the scientific demands, a MeBoCORK monitoring system will allow in situ measurements of eg. temperature and pressure. The "MeBoCORK" will be equipped with data loggers and data transmission interface for reading out the collected data from the vessel. By additional payload installation on the MeBoCORK with an ROV it will be possible to increase the energy capacity as well as to conduct fluid sampling in the bore hole for geochemical analyses. It is planned to install a prototype of this additional payload with the MARUM ROV QUEST4000M during the following R/V SONNE cruise in July 2012.

  19. Shock Wave Boundary Layer Interaction Control Using Pulsed DBD Plasma Actuators Project (United States)

    National Aeronautics and Space Administration — Active flow control using dielectric barrier discharge (DBD) plasma actuators is an attractive option for both reduction of complexity of aircraft systems required...

  20. Closed-loop performance of an actuated deformable carbon fiber reinforced polymer mirror (United States)

    Wilcox, Christopher C.; Jungwirth, Matthew E. L.; Wick, David V.; Baker, Michael S.; Hobart, Clinton G.; Romeo, Robert C.; Martin, Robert N.


    The Naval Research Laboratory and Sandia National Laboratories have been actively researching the use of carbon fiber reinforced polymer material as optical elements in many optical systems. Active optical elements can be used to build an optical system capable of changing is optical zoom. We have developed a two-element optical system that uses a large diameter, thin-shelled carbon fiber reinforced polymer mirror, actuated with micro-positioning motors, and a high actuator density micro-electro-mechanical deformable mirror. Combined with a Shack-Hartmann wavefront sensor, we have optimized this actuated carbon fiber reinforced polymer deformable mirror's surface for use with a forthcoming reflective adaptive optical zoom system. In this paper, we present the preliminary results of the carbon fiber reinforced polymer deformable mirror's surface quality and the development of the actuation of it.

  1. Gearing up for optical microrobotics: micromanipulation and actuation of synthetic microstructures by optical forces

    DEFF Research Database (Denmark)

    Palima, Darwin; Glückstad, Jesper


    Optics is usually integrated into robotics as part of intelligent vision systems. At the microscale, however, optical forces can cause significant acceleration and so optical trapping and optical manipulation can enable the noncontact actuation of microcomponents. Microbeads are ubiquitous...

  2. Toward standardization of EAP actuators test procedures (United States)

    Fernandez, Diego; Moreno, Luis; Baselga, Juan


    Since the field of Electroactive Polymers (EAP) actuators is fairly new there are no standard testing processes for such intelligent materials. This drawback can seriously limit the scope of application of EAP actuators, since the targeted industrial sectors (aerospace, biomedical...) demand high reliability and product assurance. As a first iteration two elements are required to define a test standard for an EAP actuator: a Unit Tester, and a Component Specification. In this paper a EAP Unit Tester architecture is presented along with the required classification of measurements to be included in the EAP actuator Component Specification. The proposed EAP Unit Tester allows on-line monitoring and recording of the following properties of the specimen under test: large deformation, small tip displacement, temperature at the electrodes, weight of the specimen, voltage and current driven into the EAP, load being applied to the actuator, output voltage of the EAP in sensing operation and mode of operation (structure/sensor/actuator/smart). The measurements are taken simultaneously, in real-time. The EAP Unit Tester includes a friendly Graphical User Interface. It uses embedded Excel tools to visualize data. In addition, real-time connectivity with MATLAB allows an easy testing of control algorithms. A novel methodology to measure the properties of EAP specimens versus a variable load is also presented. To this purpose a force signals generator in the range of mN was developed. The device is based on a DC mini-motor. It generates an opposing force to the movement of the EAP actuator. Since the device constantly opposes the EAP actuator movement it has been named Digital Force Generator (DFG). The DFG design allows simultaneous length and velocity measuring versus different load signals. By including such a device in the EAP Unit Tester the most suitable application for the specimen under test can be easily identified (vibration damper, large deformation actuator, large

  3. Behavioral responses of brown shrimp (Crangon crangon) to reduced seawater pH following simulated leakages from sub-sea geological storage of CO2. (United States)

    Bamber, Shaw D; Westerlund, Stig


    Large-scale storage of CO2 within sub-sea geological formations is a viable option for reducing the volume of this greenhouse gas released directly to the atmosphere from anthropogenic activities. Risks to benthic marine life following possible leakage of gas through the seabed from this carbon capture and storage (CCS) initiative are not yet well established. This study examined behavior (activity patterns) in brown shrimp (Crangon crangon), exposed to a range of reduced seawater pH conditions (7.6, 7, or 6.5) simulating leakage scenarios of varying scales. Brown shrimp have an endogenous rhythmicity associated with their activity, which dictates they are most active during hours of darkness, presumably as protection against vision-dependent predators. This endogenous rhythm in activity continues to be expressed when shrimp are held under constant low-light conditions in the lab and provides an ecologically relevant endpoint to measure when examining the influence of reduced pH on the behavior of these animals. No marked differences in activity pattern were observed between control shrimp maintained at pH 8.1 and those at pH 7.6. However, changes in activity were evident at pH 7 and pH 6.5, where significant shifts in timing and intensity of activity occurred. There was an unexpected increase in activity within periods of expected light, probably signaling efforts by shrimp to migrate away from reduced seawater pH conditions. The loss of this important member of the benthic community due to migration may have important consequences for many of the resilient species that remain.

  4. Highly efficient electrocaloric cooling with electrostatic actuation (United States)

    Ma, Rujun; Zhang, Ziyang; Tong, Kwing; Huber, David; Kornbluh, Roy; Ju, Yongho Sungtaek; Pei, Qibing


    Solid-state refrigeration offers potential advantages over traditional cooling systems, but few devices offer high specific cooling power with a high coefficient of performance (COP) and the ability to be applied directly to surfaces. We developed a cooling device with a high intrinsic thermodynamic efficiency using a flexible electrocaloric (EC) polymer film and an electrostatic actuation mechanism. Reversible electrostatic forces reduce parasitic power consumption and allow efficient heat transfer through good thermal contacts with the heat source or heat sink. The EC device produced a specific cooling power of 2.8 watts per gram and a COP of 13. The new cooling device is more efficient and compact than existing surface-conformable solid-state cooling technologies, opening a path to using the technology for a variety of practical applications.

  5. Math Machines: Using Actuators in Physics Classes (United States)

    Thomas, Frederick J.; Chaney, Robert A.; Gruesbeck, Marta


    Probeware (sensors combined with data-analysis software) is a well-established part of physics education. In engineering and technology, sensors are frequently paired with actuators—motors, heaters, buzzers, valves, color displays, medical dosing systems, and other devices that are activated by electrical signals to produce intentional physical change. This article describes how a 20-year project aimed at better integration of the STEM disciplines (science, technology, engineering and mathematics) uses brief actuator activities in physics instruction. Math Machines "actionware" includes software and hardware that convert virtually any free-form, time-dependent algebraic function into the dynamic actions of a stepper motor, servo motor, or RGB (red, green, blue) color mixer. With wheels and a platform, the stepper motor becomes LACI, a programmable vehicle. Adding a low-power laser module turns the servo motor into a programmable Pointer. Adding a gear and platform can transform the Pointer into an earthquake simulator.

  6. Analytical optimization of coating properties for actuators and sensors (United States)

    Carman, Gregory; Reifsnider, Kenneth


    An elasticity solution is presented for the problem of continuous cylindrically shaped coated sensor/actuator embedded in a material system subjected to transverse strains. Results are presented for an AS4/epon 828 material system containing fiber optic sensors coated with different interphase materials. These data demonstrate that an optical coating stiffness and thickness exists which minimizes the stress state in the host material. The optimal interphase corresponds to an integrated material system whose transverse stiffness values are similar to the host material. The results suggest that with the optimal interphase region, the onset of damage can successfully be delayed and may provide a material system whose transverse strength rivals that of the host material. Design curves are also presented for optimizing the interphase coating thickness and modulus for a general family of sensors and actuators.

  7. Eyeball pseudo-muscular actuators for an android face (United States)

    Carpi, Federico; De Rossi, Danilo


    The human attention system is based on the capability of the eye of focusing and tracking. These actions are performed by the eyeball muscle system, as a consequence of visual stimuli. The F.A.C.E. (Facial Automaton for Conveying Emotions) project at our lab concerns the development of an android face endowed with dynamic expressiveness and artificial vision. Aimed at realising an artificial attention system for such an automaton, we present here a study for the development of pseudo-muscular polymer actuators for its eyeballs. The system is based on the mimicry of the muscular architecture of the human eye. In particular, linear actuators made of dielectric elastomers have been designed to replicate actions exerted by the main ocular muscles.

  8. A swimming robot actuated by living muscle tissue

    Directory of Open Access Journals (Sweden)

    Herr Hugh


    Full Text Available Abstract Biomechatronics is the integration of biological components with artificial devices, in which the biological component confers a significant functional capability to the system, and the artificial component provides specific cellular and tissue interfaces that promote the maintenance and functional adaptation of the biological component. Based upon functional performance, muscle is potentially an excellent mechanical actuator, but the larger challenge of developing muscle-actuated, biomechatronic devices poses many scientific and engineering challenges. As a demonstratory proof of concept, we designed, built, and characterized a swimming robot actuated by two explanted frog semitendinosus muscles and controlled by an embedded microcontroller. Using open loop stimulation protocols, the robot performed basic swimming maneuvers such as starting, stopping, turning (turning radius ~400 mm and straight-line swimming (max speed >1/3 body lengths/second. A broad spectrum antibiotic/antimycotic ringer solution surrounded the muscle actuators for long term maintenance, ex vivo. The robot swam for a total of 4 hours over a 42 hour lifespan (10% duty cycle before its velocity degraded below 75% of its maximum. The development of functional biomechatronic prototypes with integrated musculoskeletal tissues is the first critical step toward the long term objective of controllable, adaptive and robust biomechatronic robots and prostheses.

  9. Modeling and optimization of magnetostrictive actuator amplified by compliant mechanism (United States)

    Niu, Muqing; Yang, Bintang; Yang, Yikun; Meng, Guang


    Magnetostrictive actuators are commonly used in precision engineering with the advantages of high resolution and fast response. Their limited strokes are always amplified by compliant mechanisms without wear and backlash. This paper proposes a hybrid model for the actuation system considering the coupling of the actuator and the amplifier. The magnetostrictive model, based on the Jiles-Atherton model, is related to the input stiffness of the amplifier when quantifying the magneto-mechanical effects, including stress-dependent magnetization, stress-dependent magnetostriction and ΔE effect. The compliant mechanism model aims at constructing the flexibility matrix with the amplification ratio and input stiffness related to the spring factor of the load. The deformation and structural stress of the amplifier are also dependent on the output strain of magnetostrictive material. Experiments under both free load and spring load conditions have been done to verify the effectiveness of the hybrid model. The proposed model is suitable for parameter optimization and the performance indicators can be precisely quantified. Optimization based on hybrid model is more preferred than optimizing the actuator and amplifier independently for maximum output displacement. Furthermore, ‘stiffness match principle’ is no longer applicable when considering ΔE effect, and the optimal external stiffness problem can be numerically solved by the hybrid model for maximum output energy of magnetostrictive material.

  10. On electrostatically actuated NEMS/MEMS circular plates (United States)

    Caruntu, Dumitru I.; Alvarado, Iris


    This paper deals with electrostatically actuated micro and nano-electromechanical (MEMS/NEMS) circular plates. The system under investigation consists of two bodies, a deformable and conductive circular plate placed above a fixed, rigid and conductive ground plate. The deformable circular plate is electrostatically actuated by applying an AC voltage between the two plates. Nonlinear parametric resonance and pull-in occur at certain frequencies and relatively large AC voltage, respectively. Such phenomena are useful for applications such as sensors, actuators, switches, micro-pumps, micro-tweezers, chemical and mass sensing, and micro-mirrors. A mathematical model of clamped circular MEMS/NEMS electrostatically actuated plates has been developed. Since the model is in the micro- and nano-scale, surface forces, van der Waals and/or Casimir, acting on the plate are included. A perturbation method, the Method of Multiple Scales (MMS), is used for investigating the case of weakly nonlinear MEMS/NEMS circular plates. Two time scales, fast and slow, are considered in this work. The amplitude-frequency and phase-frequency response of the plate in the case of primary resonance are obtained and discussed.

  11. An experimental study of icing control using DBD plasma actuator (United States)

    Cai, Jinsheng; Tian, Yongqiang; Meng, Xuanshi; Han, Xuzhao; Zhang, Duo; Hu, Haiyang


    Ice accretion on aircraft or wind turbine has been widely recognized as a big safety threat in the past decades. This study aims to develop a new approach for icing control using an AC-DBD plasma actuator. The experiments of icing control (i.e., anti-/de-icing) on a cylinder model were conducted in an icing wind tunnel with controlled wind speed (i.e., 15 m/s) and temperature (i.e., -10°C). A digital camera was used to record the dynamic processes of plasma anti-icing and de-icing whilst an infrared imaging system was utilized to map the surface temperature variations during the anti-/de-icing processes. It was found that the AC-DBD plasma actuator is very effective in both anti-icing and de-icing operations. While no ice formation was observed when the plasma actuator served as an anti-icing device, a complete removal of the ice layer with a thickness of 5 mm was achieved by activating the plasma actuator for ˜150 s. Such information demonstrated the feasibility of plasma anti-/de-icing, which could potentially provide more effective and safer icing mitigation strategies.

  12. Cylindrical dielectric elastomer actuators reinforced with inextensible fibers (United States)

    Goulbourne, Nakhiah C. S.


    Novel actuator configurations for various applications can be obtained using cylindrical dielectric elastomer actuators. A new configuration for a contractile electro-elastomer is presented here for the first time. A cylindrical or tubular configuration is used to realize simultaneous axial shortening and radial expansion when a voltage is applied across the thickness of the hollow cylinder. In this configuration, the inner and outer surfaces of a cylindrical dielectric elastomer are coated with compliant electrodes. The outer cylindrical surface is then enclosed by a network of helical fibers that are very thin, very flexible and inextensible. Fiber networks or cord families are commonly used in many different materials and for a variety of applications. The primary purpose of these networks is structural, that is to say, for reinforcement. The composite active structure proposed here is reminiscent of the McKibben actuator, a pneumatically actuated cylindrical construct consisting of a flexible rubber bladder sheathed in a fiber network, which garners its impressive contracting force from the inextensible fibers that prevent axial extension when an inflation pressure is applied to the internal bladder [1]. The system is modeled using an electro- elastic formulation derived from the large deformation theory of reinforced cylinders [2]. The model combines Maxwell-Faraday electrostatics and nonlinear elasticity theory [3]. Illustratively, solutions are obtained assuming a Mooney-Rivlin material model for a silicone actuator. The results indicate that the relationship between the axial contraction force and the axial shortening is linear for the voltage range considered. The importance of other system parameters such as the fiber angle and the applied constant pressure is also reported.

  13. Engineered setpoints for autonomous distributed sensors and actuators (United States)

    Edmunds, Thomas A


    Loads on an electric power system are configured with under-frequency relays in which the frequency setpoints and delay times for reclosure are uniformly distributed. If demand exceeds supply in the system, frequency will decrease. The decrease in frequency will actuate relays and reduce load to the point where demand will meet the available supply. After its engineered delay time, each relay will attempt to close contact and reestablish the load.

  14. Dynamic Actuation of Single-Crystal Diamond Nanobeams (United States)


    United States E-mail: KEYWORDS: Single-crystal diamond, nanoelectromechanical systems ( NEMS ), nanofabrica- tion...actuate and transduce motion of na- noelectromechanical systems ( NEMS ) and applied to achieve mechanical resonance tuning,20 and coherent control of...wavelength used. Geometrical nonlinearity is the most common nonlinearity observed in NEMS , and according to theory results in a hardening effect.26 In

  15. Synthetic Jet Actuator Performance Enhancement (United States)

    Pikcilingis, Lucia; Housley, Kevin; Whalen, Ed; Amitay, Michael; Rensselaer Polytechnic Institute Collaboration; Boeing Company Collaboration


    Over the last 20 years synthetic jets have been studied as a means for aerodynamic flow control. Specifically, synthetic jets provide momentum transfer with zero-net mass flux, which has been proven to be effective for controlling flow fields. A synthetic jet is created by the periodic formation of vortex rings at its orifice due to the periodic motion of a piezoelectric disk(s). The present study seeks to optimize the performance of a synthetic jet actuator by utilizing different geometrical parameters such as disk thickness, orifice width and length, cavity height and cavity diameter, and different input parameters such as voltage and frequency. Experiments were conducted using a synthetic jet apparatus designed for various geometrical parameters utilizing a dual disk configuration. Velocity and temperature measurements were acquired at the center of the synthetic jet orifice using a temperature compensated hotwire and thermocouple probe. The disk displacement was measured at the center of the disk with a laser displacement sensor. It was shown that the synthetic jet actuators are capable of exceeding peak velocities of 200 m/s with a relatively large orifice. Data suggests that jet velocities greater than 200 m/s are attainable.

  16. Actuator Fault Detection and Diagnosis for Quadrotors

    NARCIS (Netherlands)

    Lu, P.; Van Kampen, E.J.; Yu, B.


    This paper presents a method for fault detection and diagnosis of actuator loss of effectiveness for a quadrotor helicopter. This paper not only considers the detection of the actuator loss of effectiveness faults, but also addresses the diagnosis of the faults. The detection and estimation of the

  17. Active vibration control using DEAP actuators (United States)

    Sarban, Rahimullah; Jones, Richard W.


    Dielectric electro-active polymer (DEAP) is a new type of smart material, which has the potential to be used to provide effective actuation for a wide range of applications. The properties of DEAP material place it somewhere between those of piezoceramics and shape memory alloys. Of the range of DEAP-based actuators that have been developed those having a cylindrical configuration are among the most promising. This contribution introduces the use of a tubular type DEAP actuator for active vibration control purposes. Initially the DEAP-based tubular actuator to be used in this study, produced by Danfoss PolyPower A/S, is introduced along with the static and dynamic characteristics. Secondly an electromechanical model of the tubular actuator is briefly reviewed and its ability to model the actuator's hysteresis characteristics for a range of periodic input signals at different frequencies demonstrated. The model will be used to provide hysteresis compensation in future vibration isolation studies. Experimental active vibration control using the actuator is then examined, specifically active vibration isolation of a 250 g mass subject to shaker generated 'ground vibration'. An adaptive feedforward control strategy is used to achieve this. The ability of the tubular actuator to reject both tonal and broadband random vibratory disturbances is then demonstrated.

  18. Artificial Cilia : Mimicking Nature Through Magnetic Actuation

    NARCIS (Netherlands)

    Khaderi, S. N.; Baltussen, M. G. H. M.; Anderson, P. D.; Ioan, D.; den Toonder, J.M.J.; Onck, P. R.; Murthy, SK; Khan, SA; Ugaz, VM; Zeringue, HC


    Manipulation of bio-fluids in microchannels faces many challenges in the development of lab-on-a-chip devices. We propose magnetically actuated artificial cilia which can propel fluids in microchannels. These cilia are magnetic films which can be actuated by an external magnetic field, leading to an

  19. Conducting Polymer Actuators: Prospects and Limitations

    DEFF Research Database (Denmark)

    Skaarup, Steen

    Actuators constructed with a conjugated polymer as the active part have been predicted to have a number of highly desirable properties: Large mechanical strength, high power density, i.e. high actuation speeds possible, sufficient maximum strain values, high reversibility and safe, low voltages (1...

  20. Conjugated Polymer Actuators: Prospects and Limitations

    DEFF Research Database (Denmark)

    Skaarup, Steen


    Actuators constructed with a conjugated polymer as the active part have been predicted to have a number of highly desirable properties: Large mechanical strength, high power density, i.e. high actuation speeds possible, sufficient maximum strain values, high reversibility and safe, low voltages (1...

  1. Design optimization of a linear actuator

    DEFF Research Database (Denmark)

    Rechenbach, B.; Willatzen, Morten; Preisler, K. Lorenzen


    The mechanical contacting of a dielectric elastomer actuator is investigated. The actuator is constructed by coiling the dielectric elastomer around two parallel metal rods, similar to a rubber band stretched by two index fingers. The goal of this paper is to design the geometry and the mechanical...

  2. Numerical investigation of aerodynamic flow actuation produced by surface plasma actuator on 2D oscillating airfoil

    Directory of Open Access Journals (Sweden)

    Minh Khang Phan


    Full Text Available Numerical simulation of unsteady flow control over an oscillating NACA0012 airfoil is investigated. Flow actuation of a turbulent flow over the airfoil is provided by low current DC surface glow discharge plasma actuator which is analytically modeled as an ion pressure force produced in the cathode sheath region. The modeled plasma actuator has an induced pressure force of about 2 kPa under a typical experiment condition and is placed on the airfoil surface at 0% chord length and/or at 10% chord length. The plasma actuator at deep-stall angles (from 5° to 25° is able to slightly delay a dynamic stall and to weaken a pressure fluctuation in down-stroke motion. As a result, the wake region is reduced. The actuation effect varies with different plasma pulse frequencies, actuator locations and reduced frequencies. A lift coefficient can increase up to 70% by a selective operation of the plasma actuator with various plasma frequencies and locations as the angle of attack changes. Active flow control which is a key advantageous feature of the plasma actuator reveals that a dynamic stall phenomenon can be controlled by the surface plasma actuator with less power consumption if a careful control scheme of the plasma actuator is employed with the optimized plasma pulse frequency and actuator location corresponding to a dynamic change in reduced frequency.

  3. Advanced Actuator Concepts for High Precision Deformable Mirrors Project (United States)

    National Aeronautics and Space Administration — TRS Technologies proposes to develop a variety of single crystal actuators for adaptive optics deformable mirrors. Single crystal piezoelectric actuators are...

  4. Engineering Design Tools for Shape Memory Alloy Actuators: CASMART Collaborative Best Practices and Case Studies (United States)

    Wheeler, Robert W.; Benafan, Othmane; Gao, Xiujie; Calkins, Frederick T; Ghanbari, Zahra; Hommer, Garrison; Lagoudas, Dimitris; Petersen, Andrew; Pless, Jennifer M.; Stebner, Aaron P.; hide


    The primary goal of the Consortium for the Advancement of Shape Memory Alloy Research and Technology (CASMART) is to enable the design of revolutionary applications based on shape memory alloy (SMA) technology. In order to help realize this goal and reduce the development time and required experience for the fabrication of SMA actuation systems, several modeling tools have been developed for common actuator types and are discussed herein along with case studies, which highlight the capabilities and limitations of these tools. Due to their ability to sustain high stresses and recover large deformations, SMAs have many potential applications as reliable, lightweight, solid-state actuators. Their advantage over classical actuators can also be further improved when the actuator geometry is modified to fit the specific application. In this paper, three common actuator designs are studied: wires, which are lightweight, low-profile, and easily implemented; springs, which offer actuation strokes upwards of 200 at reduced mechanical loads; and torque tubes, which can provide large actuation forces in small volumes and develop a repeatable zero-load actuation response (known as the two-way shape memory effect). The modeling frameworks, which have been implemented in the design tools, are developed for each of these frequently used SMA actuator types. In order to demonstrate the versatility and flexibility of the presented design tools, as well as validate their modeling framework, several design challenges were completed. These case studies include the design and development of an active hinge for the deployment of a solar array or foldable space structure, an adaptive solar array deployment and positioning system, a passive air temperature controller for regulation flow temperatures inside of a jet engine, and a redesign of the Corvette active hatch, which allows for pressure equalization of the car interior. For each of the presented case studies, a prototype or proof

  5. DEAP actuator and its high voltage driver for heating valve application

    DEFF Research Database (Denmark)

    Huang, Lina; Nørmølle, L. F.; Sarban, R.


    Due to the advantages of DEAP (Dielectric Electro Active Polymer) material, such as light weight, noise free operation, high energy and power density and fast response speed, it can be applied in a variety of applications to replace the conventional transducers or actuators. This paper introduces...... is illustrated in detail, and followed by the detailed investigation of the HV driver for DEAP actuator. In order to verify the implementation, the experimental measurements are carried out for DEAP actuator, its HV driver as well as the entire heating valve system....

  6. Instability analysis of torsional MEMS/NEMS actuators under capillary force. (United States)

    Guo, Jian-Gang; Zhou, Li-Jun; Zhao, Ya-Pu


    The static and dynamic instabilities of a torsional MEMS/NEMS actuator caused by capillary effects are studied, respectively. An instability number, eta, is defined, and the critical gap distance, g(cr), between the mainplate and the substrate is derived. According to the values of eta and g, the instability criteria of the actuator are presented. The dimensionless motion equation of the MEMS/NEMS torsional actuator is derived when it makes nonlinear oscillation under capillary force. The qualitative analysis of the nonlinear equation is made, and the phase portraits are presented on the phase plane. In addition, the bifurcation phenomena in the system are also analyzed.

  7. Microfabrication of stacked dielectric elastomer actuator fibers (United States)

    Corbaci, Mert; Walter, Wayne; Lamkin-Kennard, Kathleen


    Dielectric elastomer actuators (DEA) are one of the best candidate materials for next generation of robotic actuators, soft sensors and artificial muscles due to their fast response, mechanical robustness and compliance. However, high voltage requirements of DEAs have impeded their potential to become widely used in such applications. In this study, we propose a method for fabrication of silicon based multilayer DEA fibers composed of microlevel dielectric layers to improve the actuation ratios of DEAs at lower voltages. A multi-walled carbon nanotube - polydimethylsiloxane (MWCNT/PDMS) composite was used to fabricate mechanically compliant, conductive parallel plates and electrode connections for the DEA actuators. Active surface area and layer thickness were varied to study the effects of these parameters on actuation ratio as a function of applied voltage. Different structures were fabricated to assess the flexibility of the fabrication method for specific user-end applications.

  8. Design of multiphysics actuators using topology optimization - Part II

    DEFF Research Database (Denmark)

    Sigmund, Ole


    of the topology optimization method in this part include design descriptions for two-material structures, constitutive modelling of elements with mixtures of two materials, formulation of optimization problems with multiple constraints and multiple materials and a mesh-independency scheme for two......This is the second part of a two-paper description of the topology optimization method applied to the design of multiphysics actuators and electrothermomechanical systems in particular. The first paper is focussed on one-material structures, the second on two-material structures. The extensions......-material structures. The application in mind is the design of thermally and electro thermally driven micro actuators for use in MicroElectroMechanical Systems (MEMS). MEMS are microscopic mechanical systems coupled with electrical circuits. MEMS are fabricated using techniques known from the semi-conductor industry...

  9. Shape Memory Alloy Actuator Design: CASMART Collaborative Best Practices (United States)

    Benafan, Othmane; Brown, Jeff; Calkins, F. Tad; Kumar, Parikshith; Stebner, Aaron; Turner, Travis; Vaidyanathan, Raj; Webster, John; Young, Marcus L.


    Upon examination of shape memory alloy (SMA) actuation designs, there are many considerations and methodologies that are common to them all. A goal of CASMART's design working group is to compile the collective experiences of CASMART's member organizations into a single medium that engineers can then use to make the best decisions regarding SMA system design. In this paper, a review of recent work toward this goal is presented, spanning a wide range of design aspects including evaluation, properties, testing, modeling, alloy selection, fabrication, actuator processing, design optimization, controls, and system integration. We have documented each aspect, based on our collective experiences, so that the design engineer may access the tools and information needed to successfully design and develop SMA systems. Through comparison of several case studies, it is shown that there is not an obvious single, linear route a designer can adopt to navigate the path of concept to product. SMA engineering aspects will have different priorities and emphasis for different applications.

  10. Actuators Using Piezoelectric Stacks and Displacement Enhancers (United States)

    Bar-Cohen, Yoseph; Sherrit, Stewart; Bao, Xiaoqi; Badescu, Mircea; Lee, Hyeong Jae; Walkenmeyer, Phillip; Lih, Shyh-Shiuh


    Actuators are used to drive all active mechanisms including machines, robots, and manipulators to name a few. The actuators are responsible for moving, manipulating, displacing, pushing and executing any action that is needed by the mechanism. There are many types and principles of actuation that are responsible for these movements ranging from electromagnetic, electroactive, thermo-mechanic, piezoelectric, electrostrictive etc. Actuators are readily available from commercial producers but there is a great need for reducing their size, increasing their efficiency and reducing their weight. Studies at JPL’s Non Destructive Evaluation and Advanced Actuators (NDEAA) Laboratory have been focused on the use of piezoelectric stacks and novel designs taking advantage of piezoelectric’s potential to provide high torque/force density actuation and high electromechanical conversion efficiency. The actuators/motors that have been developed and reviewed in this paper are operated by various horn configurations as well as the use of pre-stress flexures that make them thermally stable and increases their coupling efficiency. The use of monolithic designs that pre-stress the piezoelectric stack eliminates the use of compression stress bolt. These designs enable the embedding of developed solid-state motors/actuators in any structure with the only macroscopically moving parts are the rotor or the linear translator. Finite element modeling and design tools were used to determine the requirements and operation parameters and the results were used to simulate, design and fabricate novel actuators/motors. The developed actuators and performance will be described and discussed in this paper.

  11. High precision cell slicing by harmonically actuated ultra-sharp SixNy blades (United States)

    Jeong, Hwapyeong; Li, Tao; Gianchandani, Yogesh B.; Park, Jaesung


    We describe a micro-knife system with an ultra-sharp blade that is harmonically actuated by lead zirconate titanate (PZT). In particular, harmonic actuation along its cutting direction is demonstrated to provide clean and sharp cut lines for hepatocytes. Such performance is not provided by ordinary ultrasonic actuation. The blade is 500 nm-thick silicon nitride (SixNy); it can cut a single cell. Finite element analysis and measurements of displacement around resonant frequencies were used to optimize the dimensions, driving frequency and voltage. To evaluate the cutting precision, commercial scalpels and the SixNy blade without and with harmonic actuation were compared. When used to cut primary hepatocytes in a mono-layer, a commercial stainless scalpel burst cells, and the SixNy blade without harmonic actuation cut cells with a wide and ragged line. However, due to the controlled ultrasonic mode shape, operating frequency, high frequency and low applied power, the SixNy blade with harmonic actuation at 1Vpp and 70.1 kHz provided a clean and sharp cut line which was as narrow as 2 µm. The SixNy blade with harmonic actuation has potential applications as a tool for minimally invasive surgery.

  12. Characteristic Evaluation of a Shrouded Propeller Mechanism for a Magnetic Actuated Microrobot

    Directory of Open Access Journals (Sweden)

    Qiang Fu


    Full Text Available Medical microrobots have been widely used in clinical applications, particularly the spiral type locomotion mechanism, which was recently considered one of the main self-propelling mechanisms for the next medical microrobot to perform tasks such as capsule endoscopy and drug delivery. However, limits in clinical applications still exist. The spiral action of the microrobot while being used for diagnosis may lead to pain or even damage to the intestinal wall due to the exposed mechanisms. Therefore, a new locomotive mechanism, named the shrouded propeller mechanism, was proposed to achieve a high level of medical safety as well as effective propulsive performance in our study. The shrouded propeller mechanism consists of a bare spiral propeller and a non-rotating nozzle. To obtain a high effective propulsive performance, two types of screw grooves with different shapes including the cylindrical screw groove and the rectangular screw groove with different parameters were analyzed using the shrouded model. Two types of magnetic actuated microrobots with different driving modes, the electromagnetic (three-pole rotor actuated microrobot and the permanent magnet (O-ring type magnet actuated microrobot were designed to evaluate the performance of the electromagnetic actuation system. Based on experimental results, the propulsive force of the proposed magnetic actuated microrobot with a shrouded propeller was larger than the magnetic actuated microrobot with a bare spiral propeller under the same parameters. Additionally, the shrouded propeller mechanism as an actuator can be used for other medical microrobots for flexible locomotion.

  13. Robust control of dielectric elastomer diaphragm actuator for human pulse signal tracking (United States)

    Ye, Zhihang; Chen, Zheng; Asmatulu, Ramazan; Chan, Hoyin


    Human pulse signal tracking is an emerging technology that is needed in traditional Chinese medicine. However, soft actuation with multi-frequency tracking capability is needed for tracking human pulse signal. Dielectric elastomer (DE) is one type of soft actuating that has great potential in human pulse signal tracking. In this paper, a DE diaphragm actuator was designed and fabricated to track human pulse pressure signal. A physics-based and control-oriented model has been developed to capture the dynamic behavior of DE diaphragm actuator. Using the physical model, an H-infinity robust control was designed for the actuator to reject high-frequency sensing noises and disturbances. The robust control was then implemented in real-time to track a multi-frequency signal, which verified the tracking capability and robustness of the control system. In the human pulse signal tracking test, a human pulse signal was measured at the City University of Hong Kong and then was tracked using DE actuator at Wichita State University in the US. Experimental results have verified that the DE actuator with its robust control is capable of tracking human pulse signal.

  14. Low power valve actuation using trans-permanent magnetics (United States)

    Duval, Luis Denit

    The subject of magnetic actuators is very broad, and encompasses a wide range of technologies, magnetic circuit topologies, and performance characteristics for an ever-increasing spectrum of applications. As a consequence of recent advances in soft and hard magnetic materials and developments in power electronics, microprocessors and digital control strategies, and the continuing demand for higher performance motion control systems, there appears to be more research and development activity in magnetic actuators for applications spanning all market sectors than at any time. In this dissertation, a rational approach for switching the states of permanent magnets through an on-board magnetization process is presented. The resulting dynamic systems are referred to as trans-permanent magnetic systems (T-PM). The first part of this research focuses on the governing equations needed for the analysis of T-PM systems. Their feasibility is demonstrated experimentally. In doing so, a method that has the potential of leading to new ultra-low power designs for electromechanical devices is introduced. In the second part of this research, the aforementioned developments in T-PM are applied to the problem of low power valves. Whereas alternate approaches to low power valve control may utilize latching mechanisms to maintain valve position during inactive periods, an approach that eliminates latching mechanisms is presented. Instead, the principles of T-PM are employed to switch the states of permanent magnets; the used of permanent magnets instead of electromagnets eliminates power consumption during inactive periods, thereby reducing power consumption to ultra-low levels. The magnets in a T-PM actuator are configured in a stack. The relationships between the strength and number of magnets in the stack and the stroke and resolution of the actuator are developed. This dissertation reports on the design and testing of a prototype valve actuator that uses a stack pf T-PM with

  15. An electro-mechanically coupled model for the dynamic behavior of a dielectric electro-active polymer actuator (United States)

    Hodgins, M.; Rizzello, G.; Naso, D.; York, A.; Seelecke, S.


    Dielectric electro-active polymer (DEAP) technology holds promise for enabling lightweight, energy efficient, and scalable actuators. The circular DEAP actuator configuration (also known as cone or diaphragm actuator) in particular shows potential in applications such as pumps, valves, micro-positioners and loudspeakers. For a quantitative prediction of the actuator behavior as well as for design optimization tasks, material models which can reproduce the coupled electromechanical behavior inherent to these actuators are necessary. This paper presents a non-linear viscoelastic model based on an electro-mechanical Ogden free energy expression for the DEAP. The DEAP model is coupled with a spring/mass system to study the dynamic performance of such a representative system from static behavior to 50 Hz. The system is identified and validated by several different experiments.

  16. A Roll Controlling Approach for a Simple Dual-Actuated Flapping Aerial Vehicle Model

    Directory of Open Access Journals (Sweden)

    Labib Omar El-Farouk E.


    Full Text Available Aerial vehicles have been investigated recently in different contexts, due to their high potential of utilization in multiple application areas. Different mechanisms can be used for aerial vehicles actuation, such as the rotating multi-blade systems (Multi-Copters and more recently flapping wings. Flapping wing robots have attracted much attention from researchers in recent years. In this study, a simple dual-actuated flapping mechanism is proposed for actuating a flapping wing robot. The mechanism is designed, simulated and validated in both simulation and experiments. A roll controlling approach is proposed to control the roll angle of the robot via controlling the speeds of both motors actuating each of the wings. The results achieved are validated experimentally, and are promising opening the door for further investigation using our proposed system

  17. A Nonlinear Physics-Based Optimal Control Method for Magnetostrictive Actuators (United States)

    Smith, Ralph C.


    This paper addresses the development of a nonlinear optimal control methodology for magnetostrictive actuators. At moderate to high drive levels, the output from these actuators is highly nonlinear and contains significant magnetic and magnetomechanical hysteresis. These dynamics must be accommodated by models and control laws to utilize the full capabilities of the actuators. A characterization based upon ferromagnetic mean field theory provides a model which accurately quantifies both transient and steady state actuator dynamics under a variety of operating conditions. The control method consists of a linear perturbation feedback law used in combination with an optimal open loop nonlinear control. The nonlinear control incorporates the hysteresis and nonlinearities inherent to the transducer and can be computed offline. The feedback control is constructed through linearization of the perturbed system about the optimal system and is efficient for online implementation. As demonstrated through numerical examples, the combined hybrid control is robust and can be readily implemented in linear PDE-based structural models.


    Energy Technology Data Exchange (ETDEWEB)



    .'s (ARM) modular robotic manipulator technology developed for DOE EM operations, which addresses many of the issues discussed in the previous section. This manipulator system has the capability of custom configurations, which accommodate common glovebox tasks such as materials repackaging. The modular nature and quick connects of this system simplify installations into ''hot'' boxes and any potential modifications or repair therein. In the field of automation and robotics, a very common element is one used to generate motion for precise positioning of loads. One example of such an automation component would be an individual joint within an industrial robotic manipulator. This component consists of a tightly integrated package containing an electric motor, gear train, output support bearings, position sensors, brake, servo-amplifier and communications controller. Within the context of this paper, this key building block is referred to as an actuator module. With regard to the needs of the EM, [8] and [9] have shown that while each focus area has unique requirements for robotic automation at a system or manipulator level, their requirements at the actuator level are very similar. Thereby, a modular approach to automation which utilizes a small set of versatile actuator modules can be used to construct a broad range of robotic systems and automation cells suited to EM applications. By providing a pre-engineered, pre-integrated motion system to different robotics users within the DOE, new automation systems can be more quickly created without extensive expertise in motion control or the expense of building custom equipment.

  19. Optothermally actuated capillary burst valve (United States)

    Eriksen, Johan; Bilenberg, Brian; Kristensen, Anders; Marie, Rodolphe


    We demonstrate the optothermal actuation of individual capillary burst valves in an all-polymer microfluidic device. The capillary burst valves are realised in a planar design by introducing a fluidic constriction in a microfluidic channel of constant depth. We show that a capillary burst valve can be burst by raising the temperature due to the temperature dependence of the fluid surface tension. We address individual valves by using a local heating platform based on a thin film of near infrared absorber dye embedded in the lid used to seal the microfluidic device [L. H. Thamdrup et al., Nano Lett. 10, 826-832 (2010)]. An individual valve is burst by focusing the laser in its vicinity. We demonstrate the capture of single polystyrene 7 μm beads in the constriction triggered by the bursting of the valve.

  20. Characterization of kink actuators as compared to traditional chevron shaped Bent-Beam electrothermal actuators

    KAUST Repository

    Rawashdeh, E.


    This paper compares the design and performance of kink actuators, a modified version of the bent-beam thermal actuator, to the standard chevron-shaped designs. A variety of kink and chevron actuator designs were fabricated from polysilicon. While the actuators were electrically probed, these designs were tested using a probe station connected to a National Instruments (NI) controller that uses LabVIEW to extract the displacement results via image processing. The displacement results were then used to validate the thermal-electric-structural simulations produced by COMSOL. These results, in turn, were used to extract the stiffness for both actuator types. The data extracted show that chevron actuators can have larger stiffness values with increasing offsets, but at the cost of lower amplification factors. In contrast, kink actuators showed a constant stiffness value equivalent to the chevron actuator with the highest amplification factor. The kink actuator also had larger amplification factors than chevrons at all designs tested. Therefore, kink actuators are capable of longer throws at lower power levels than the standard chevron designs.