Evaluation of a Fuzzy-Based Impedance Control Strategy on a Powered Lower Exoskeleton

2015 ◽  
Vol 8 (1) ◽  
pp. 103-123 ◽  
Author(s):  
Huu Toan Tran ◽  
Hong Cheng ◽  
Huang Rui ◽  
XiChuan Lin ◽  
Mien Ka Duong ◽  
...  
Keyword(s):  
Control Strategy ◽  
Impedance Control ◽  
Lower Exoskeleton

scholarly journals BIO-BASED SUPERVISORY CONTROL OF A LOWER EXOSKELETON FOR STANCE PHASE

2018 ◽  
Vol 54 (3A) ◽  
pp. 115
Author(s):  
Tran Huu Toan
Keyword(s):  
Control Strategy ◽  
Stance Phase ◽  
Human Performance ◽  
Impedance Control ◽  
Tracking Error ◽  
Electrical Power ◽  
Biomechanical Analysis ◽  
Lower Limb Exoskeleton ◽  
Walking Speeds ◽  
Lower Exoskeleton

This paper presents a newly supervisory impedance control strategy of a wearable lower limb exoskeleton in stance phase intended to enhance human performance and support load-carrying using biomechanical analysis. In order to control the coupled human-robot system, the impedance control strategy, previously developed by the authors for swing phase, has been herein expanded up to the stance phase by regulating the desired impedance between the exoskeleton and a wearer's limb according to a specific motion speed. The effect of human behaviours on the change of impedance parameters across variable walking speeds in the stance phase is adopted to design the fuzzy rules for the control strategy. The control performance of the designed exoskeleton is evaluated on a bench-testing over different ranges of walking speeds (about 0.3 m/s to 1.2 m/s). Experimental results show that the resulting interaction torque, the human-exoskeleton tracking error, and electrical power consumption are significantly reduced as compared to a traditional impedance control, especially in the stance phase. Besides that, an average of 72.3 % of the load was transferred to the ground by the exoskeleton during the stance phase of walking. The developed control strategy on the lower exoskeleton has the potential to increase comfort and adaptation to users during daily use.

scholarly journals A Human-Inspired Control Strategy for Improving Seamless Robot-To-Human Handovers

2021 ◽  
Vol 11 (10) ◽  
pp. 4437
Author(s):  
Paramin Neranon ◽  
Tanapong Sutiphotinun
Keyword(s):  
Control System ◽  
Control Strategy ◽  
Impedance Control ◽  
Human Interaction ◽  
Robotic Control ◽  
Natural Manner ◽  
Object Handover ◽  
Overall Performance ◽  
Survey Responses ◽  
Test Outcomes

One of the challenging aspects of robotics research is to successfully establish a human-like behavioural control strategy for human–robot handover, since a robotic controller is further complicated by the dynamic nature of the human response. This paper consequently highlights the development of an appropriate set of behaviour-based control for robot-to-human object handover by first understanding an equivalent human–human handover. The optimized hybrid position and impedance control was implemented to ensure good stability, adaptability and comfort of the robot in the object handover tasks. Moreover, a questionnaire technique was employed to gather information from the participants concerning their evaluations of the developed control system. The results demonstrate that the quantitative measurement of performance of the human-inspired control strategy can be considered acceptable for seamless human–robot handovers. This also provided significant satisfaction with the overall control performance in the robotic control system, in which the robot can dexterously pass the object to the receiver in a timely and natural manner without the risk of harm or injury by the robot. Furthermore, the survey responses were in agreement with the parallel test outcomes, demonstrating significant satisfaction with the overall performance of the robot–human interaction, as measured by an average rating of 4.20 on a five-point scale.

scholarly journals Patient-Centered Robot-Aided Passive Neurorehabilitation Exercise Based on Safety-Motion Decision-Making Mechanism

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Lizheng Pan ◽  
Aiguo Song ◽  
Suolin Duan ◽  
Zhuqing Yu
Keyword(s):  
Decision Making ◽  
Control Strategy ◽  
Position Control ◽  
Impedance Control ◽  
Control Strategies ◽  
Movement Speed ◽  
Stroke Patients ◽  
Patient Centered ◽  
Motion Speed ◽  
Clinical Experiments

Safety is one of the crucial issues for robot-aided neurorehabilitation exercise. When it comes to the passive rehabilitation training for stroke patients, the existing control strategies are usually just based on position control to carry out the training, and the patient is out of the controller. However, to some extent, the patient should be taken as a “cooperator” of the training activity, and the movement speed and range of the training movement should be dynamically regulated according to the internal or external state of the subject, just as what the therapist does in clinical therapy. This research presents a novel motion control strategy for patient-centered robot-aided passive neurorehabilitation exercise from the point of the safety. The safety-motion decision-making mechanism is developed to online observe and assess the physical state of training impaired-limb and motion performances and regulate the training parameters (motion speed and training rage), ensuring the safety of the supplied rehabilitation exercise. Meanwhile, position-based impedance control is employed to realize the trajectory tracking motion with interactive compliance. Functional experiments and clinical experiments are investigated with a healthy adult and four recruited stroke patients, respectively. The two types of experimental results demonstrate that the suggested control strategy not only serves with safety-motion training but also presents rehabilitation efficacy.

Automatic deburring utilizing a real-time impedance control strategy

1993 ◽  
Vol 46 (3) ◽  
pp. 561-571 ◽  
Author(s):  
M.S. Ali ◽  
M.N. Noori ◽  
J. Turi
Keyword(s):  
Real Time ◽  
Control Strategy ◽  
Impedance Control

Impedance control of a cable-driven SEA with mixed H2/H∞ synthesis

2017 ◽  
Vol 37 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Ningbo Yu ◽  
Wulin Zou
Keyword(s):  
Control Strategy ◽  
Control Method ◽  
Impedance Control ◽  
Low Frequency ◽  
Human Robot Interaction ◽  
Control Input ◽  
Robot Interaction ◽  
Content Type ◽  
Series Elastic Actuator ◽  
Series Elastic

Purpose This paper aims to present an impedance control method with mixed H2/H∞ synthesis and relaxed passivity for a cable-driven series elastic actuator to be applied for physical human–robot interaction. Design/methodology/approach To shape the system’s impedance to match a desired dynamic model, the impedance control problem was reformulated into an impedance matching structure. The desired competing performance requirements as well as constraints from the physical system can be characterized with weighting functions for respective signals. Considering the frequency properties of human movements, the passivity constraint for stable human–robot interaction, which is required on the entire frequency spectrum and may bring conservative solutions, has been relaxed in such a way that it only restrains the low frequency band. Thus, impedance control became a mixed H2/H∞ synthesis problem, and a dynamic output feedback controller can be obtained. Findings The proposed impedance control strategy has been tested for various desired impedance with both simulation and experiments on the cable-driven series elastic actuator platform. The actual interaction torque tracked well the desired torque within the desired norm bounds, and the control input was regulated below the motor velocity limit. The closed loop system can guarantee relaxed passivity at low frequency. Both simulation and experimental results have validated the feasibility and efficacy of the proposed method. Originality/value This impedance control strategy with mixed H2/H∞ synthesis and relaxed passivity provides a novel, effective and less conservative method for physical human–robot interaction control.

Development of Mechanical-Impedance-Varying Mechanism in Admittance Control

2018 ◽  
Vol 30 (6) ◽  
pp. 863-872
Author(s):  
Toru Tsumugiwa ◽  
◽  
Miho Yura ◽  
Atsushi Kamiyoshi ◽  
Ryuichi Yokogawa
Keyword(s):  
Motion Control ◽  
Control Strategy ◽  
Impedance Control ◽  
Mechanical Impedance ◽  
Force Sensor ◽  
Robot Motion ◽  
Admittance Control ◽  
Input Force ◽  
Mechanical Variable ◽  
Impedance Parameters

There have been numerous studies on the physical human-robot cooperative task system with impedance/admittance control in robot motion control. However, the problem of stability persists, wherein the control system becomes unstable when the robot comes into contact with a highly stiff environment. A variable impedance control strategy was proposed to circumvent this stability problem. However, a number of studies on variable impedance control are based on the variation of a parameter in the robot motion control software, and a mechanical variable impedance control has not been proposed. The purpose of this research is to propose a mechanical variable impedance control strategy using a mechanical device based on the lever principle. The proposed mechanism can adjust the magnitude of the input force to the force sensor by changing the position of application of the operating force on the beam. Adjusting the magnitude of the input force to the force sensor is equivalent to varying the impedance parameters of the robot; therefore, it is feasible to achieve mechanical variable impedance control using the proposed mechanism. In this study, the gain adjustment characteristics of the proposed mechanism were evaluated. The experimental results demonstrated that the operator can vary the impedance parameters of the robot by mechanically adjusting the input force to the force sensor and operating the robot using the proposed mechanism.

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