• Title/Summary/Keyword: Dynamic Force Feedback

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Torque Sensorless Decentralized Position/Force Control for Constrained Reconfigurable Manipulator via Non-fragile H Dynamic Output Feedback

  • Zhou, Fan;Dong, Bo;Li, Yuanchun
    • Journal of Electrical Engineering and Technology
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    • v.13 no.1
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    • pp.418-429
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    • 2018
  • This paper studies the decentralized position/force control problem for constrained reconfigurable manipulator without torque sensing. A novel joint torque estimation scheme that exploits the existing structural elasticity of the manipulator joint with harmonic drive model is applied for each joint module. Based on the estimated joint torque and dynamic output feedback technique, a decentralized position/force control strategy is presented. In order to solve the problem of controller parameter perturbation, the non-fragile robust technique is introduced into the dynamic output feedback controller. Subsequently, the stability of the closed-loop system is proved using the Lyapunov theory and linear matrix inequality (LMI) technique. Finally, two 2-DOF constrained reconfigurable manipulators with different configurations are applied to verify the effectiveness of the proposed control scheme in numerical simulation.

Implementation of Position and Force Control by Modelling of a Miniatured Excavator (소형 굴삭기의 모델링을 통한 위치 및 힘제어 구현)

  • Oh, Myeong Sik;Seo, Ja Ho;Jung, Seul
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.12
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    • pp.1034-1039
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    • 2016
  • This paper presents the implementation and control of a small-scaled excavator system. The commercial miniature of an excavator system has been modified and its control hardware is embedded to access the feedback control. Encoder sensors are attached to the joint and a force sensor is mounted on the end-effector so that feedback position control is accessible as well as force control. The dynamic model of the excavator system is derived as a four linkage robot arm and its control performances are simulated. Experimental studies of contact force control tasks are conducted to test the control algorithm for the excavator system.

A Study on the Dynamic Characteristics Improvement of Direct Drive Electro-mechanical Actuation System using Dynamic Force Feedback Control (동적 하중 되먹임 제어를 사용한 직구동 방식 전기기계식 구동장치시스템의 동특성 개선에 관한 연구)

  • Lee, Hee-Joong;Kang, E-Sok;Song, Ohseop
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.4
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    • pp.328-341
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    • 2017
  • In the control actuator system of a launch vehicle based on thrust vectoring, the interaction between electro-mechanical position servo and inertial load are combined with the dynamic characteristics of the flexible vehicle support to generate synthetic resonance. This occurred resonance is fed back to the attitude control system and can influence stability of launch vehicle. In this study, we proposed a simulation model to analyze synthetic resonance of electro-mechanical actuation system for thrust vector control and explained the results of simulation and test using dynamic force feedback control which improves dynamic characteristics of servo actuation system by reducing synthetic resonance.

Reconfiguring Second-order Dynamic Systems via P-D Feedback Eigenstructure Assignment: A Parametric Method

  • Wang Guo-Sheng;Liang Bing;Duan Guang-Ren
    • International Journal of Control, Automation, and Systems
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    • v.3 no.1
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    • pp.109-116
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    • 2005
  • The design of reconfiguring a class of second-order dynamic systems via proportional plus derivative (P-D) feedback is considered. The aim is to resynthesize a P-D feedback controller such that the eigenvalues of the reconfigured closed-loop system can completely recover those of the original close-loop system, and make the corresponding eigenvectors of the former as close to those of the latter as possible. Based on a parametric result of P-D feedback eigenstructure assignment in second-order dynamic systems, parametric expressions for all the P-D feedback gains and all the closed-loop eigenvector matrices are established and a parametric algorithm for this reconfiguration design is proposed. The parametric algorithm offers all the degrees of design freedom, which can be further utilized to satisfy some additional performances in control system designs. This algorithm involves manipulations only on the original second-order system matrices, thus it is simple and convenient to use. An illustrative example and the simulation results show the simplicity and effect of the proposed parametric method.

Gain-Tuning of Sensory Feedback for a Multi-Fingered Hand Based on Muscle Physiology

  • Bae, J.H.;Arimoto, S.;Shinsuke, N.;Ozawa, R.
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.1994-1999
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    • 2003
  • This paper discusses dynamic characteristics of motion of a pair of multi-degrees of freedom robot fingers executing grasp of a rigid object and controlling its orientation with the aid of rolling contacts. In particular, the discussions are focused on a problem of gain-tuning of sensory feedback signals proposed from the viewpoint of sensorymotor coordination, which consist of a feedforward term, a feedback term for controlling rotational moment of the object, and another term for controlling its rotational angle. It is found through computer simulations of the overall fingersobject dynamics subject to rolling contact constraints that some dynamic characteristics of torque-angular velocity relation may play an important role likely as reported by experimental results in muscle physiology and therefore selection of damping gains in angular velocity feedback depending on the guess of object mass is crucial. Finally, a guidance of gain-tuning in each feedback term is suggested and its validity is discussed by various computer simulations.

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Position/Force Control of a Robot by a Nonlinear Compensator and Feedforward Control (비선형 보상기와 피드포워드 제어에 의한 로봇의 위치/힘 제어)

  • 황용연
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.2
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    • pp.232-240
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    • 1998
  • This paper deals with a hybrid position/force control of a robot which is moving on the constrained object with constant force. The proposed controller is composed of a position and force controller. The position controller has a nonlinear compensator which is based on the dynamic robot model and the force controller is attached by feedforward element. A direct drive robot with hard nonlinearity which is controlled by the proposed algorithm has moved on the constrained object with a high stiffness and low stiffness. The results show that the proposed controller has more vibration suppression effects which is occurred to the constrained object with a high stiffness, than a existing feedback controller, and accurate force control can be obtained by comparatively a small feedback gain.

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Effects of Visual Feedback-Based Balance Training on Balance in Elderly Fallers (시각되먹임 균형훈련이 낙상을 경험한 노인의 균형에 미치는 효과)

  • Lee, Sun-Woo;Lee, Kyoung-Jin;Song, Chang-Ho
    • Journal of muscle and joint health
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    • v.18 no.1
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    • pp.16-27
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    • 2011
  • Purpose: The purpose of this study was to investigate the effects of a visual feedbackbased balance training, using force platform biofeedback, on the postural balance of elderly faller. Methods: Fifty one community-dwelling older adults (aged 66-88 years) with a recent history of fall participated in the study. Participants were randomized to an experimental group (EG, n=25) and to a control group (CG, n=26). The EG participated in training sessions three times/week for 6 weeks. Visual feedbackbased balance training with the a computerized force platform with visual feedback screen was used in the experimental group. Static balance (center of gravity) and dynamic balance (Functional reach test, Timed "Up & Go" test, Berg balance scale) were assessed before and after end of training. Results: A significant improvement in static balance and dynamic balance were demonstrated within the EG (p<.05), but not in the CG. Conclusion: Visual feedback-based balance training may be an effective intervention to improve postural balance of elderly fallers.

Dynamic design of piezoelectric structures for an efficient tactile feedback of index finger on touch screen (검지의 효율적 화면접촉감응을 위한 압전-구조물계의 동적설계)

  • Park, Young-Min;Kim, Kwang-Joon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.04a
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    • pp.280-281
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    • 2009
  • Piezoelectric vibrators can be good replacements of electric motors to excite touch screen of a mobile device owing to small volume and low power consumption. One problem to be solved yet for real application is larger excitation force or moment than available currently. More efficient excitation by a piezoelectric vibrator could be achieved by operating at one of resonance frequencies of the system, which must also be as close as possible to frequency range where index finger is most sensitive and increasing transmission force or moment at that frequency. In this study, dynamic models are derived for the piezoelectric exciter and an adhesive viscoelastic layer, which connect the exciter to the screen. The adhesive layer is modeled as distributed stiffness by considering its geometric shape to relative to the piezoelectric exciter. Then, equations of motion for the piezoelectric exciter and the adhesive layer are derived using Hamilton's principle. Based on this model, dynamic characteristics of the exciter will be designed to maximize the force or moment transmitted onto the screen structure.

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A study on the Flux Feedback Approach for the Rejection of Dynamic Disturbance Forces in a Magnetically Suspended System (자기력 부상 시스템에서 외란 제거를 위한 자속 궤환 방식에 관한 연구)

  • Lee, Jun-Ho;Shin, Kyeong-Ho;Lee, Kang-Mi;Kim, Bak-Hyun;Kim, Jong-Ki;Kim, Yong-Kyu
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.1212-1217
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    • 2006
  • This study is concerned with static and sinusoidal disturbance rejection for a single periodic input disturbance with known period. In the area of active elimination of a disturbance force, the control input should have two different kinds of gains: one is to deliver a stable control and the other is a force component to cancel the external disturbance force. In this paper we employ a simple state feedback control law to make the balance beam stable and employ a linear observer to estimate the states which represent the external disturbance force components. Simulation results verify our proposed control method to reject a static and sinusoidal disturbance force.

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Effect of Feedback Methods and Ambulatory Assistive Aids on Accuracy of Partial Weight Bearing (되먹임과 보행보조도구의 형태가 30%체중지지의 정확성에 미치는 영향)

  • Park, Eun-Young;Kim, Won-Ho
    • The Journal of the Korea Contents Association
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    • v.11 no.4
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    • pp.207-214
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    • 2011
  • The purpose of this study was to investigate effect of feedback methods and ambulatory assistive aids on accuracy of partial weight bearing in healthy adults. Twenty subjects were recruited and trained to 30% weight bearing of body weight (BW) using 3-point gait crutches and wheeled walker pattern. Dynamic feedback group (n=11) was received dynamic postresponse feedback and static group (n=9) received static feedback. Force plate was used to measure %BW and GAITRite used to measure gait parameters in immediately and after 3 days of training. Immediately after training, there was not significantly at 30%BW target load in dynamic group with crutch gait (p>.05). There were significantly differences in %BW according to feedback methods and ambulatory aids (p<.05). There was not significant difference between immediately and after 3 days of training (p>0.05). There were significantly differences in gait velocity and stance ratio between crutches and wheeled walker gait (p<.05). Thus, it was suggested that if possible, use crutches, training for partial weight bearing via dynamic feedback is necessary.