Adaptive Impedance Control for a Tendon-Sheath-Driven Compliant Gripper

2014 ◽  
Vol 532 ◽  
pp. 74-77
Author(s):  
Kai Wang ◽  
Xing Song Wang
Keyword(s):  
Impedance Control ◽  
Mathematic Model ◽  
Tendon Sheath ◽  
Strain Gages ◽  
Control Scheme ◽  
Adaptive Impedance Control ◽  
Adaptive Control Strategy ◽  
Gripping Force ◽  
Model Reference Adaptive ◽  
Soft Control

This paper investigates the feasibility of adaptive impedance control scheme for compliant gripper. A compliant gripper was designed for manipulation tasks requiring precision position and force control. The gripper is actuated by tendon-sheath transmission system and use strain gages to measure both the displacement and gripping force. Position based impedance control is used to control the contact force to made the gripper more compliantly. Due to the nonlinear of the structure; it is difficult to establish the mathematic model and kinematical equations. Therefore, combine model reference adaptive control strategy with impedance control to realize the soft control of the compliant gripper.

Model reference adaptive impedance control for physical human-robot interaction

2016 ◽  
Vol 14 (1) ◽  
pp. 68-82 ◽  
Author(s):  
Bakur Alqaudi ◽  
Hamidreza Modares ◽  
Isura Ranatunga ◽  
Shaikh M. Tousif ◽  
Frank L. Lewis ◽  
...  
Keyword(s):  
Impedance Control ◽  
Human Robot Interaction ◽  
Robot Interaction ◽  
Model Reference ◽  
Adaptive Impedance Control ◽  
Model Reference Adaptive

Adaptive Impedance Control of Robot Manipulators based on Function Approximation Technique

Robotica ◽  
2004 ◽  
Vol 22 (4) ◽  
pp. 395-403 ◽  
Author(s):  
Ming-Chih Chien ◽  
An-Chyau Huang
Keyword(s):  
Function Approximation ◽  
Robot Manipulator ◽  
Impedance Control ◽  
Lyapunov Stability Theory ◽  
Approximation Technique ◽  
Control Scheme ◽  
Approximation Errors ◽  
Adaptive Impedance Control ◽  
Function Approximation Technique ◽  
Finite Linear

This paper presents an adaptive impedance control scheme for an $n$-link constrained rigid robot manipulator without using the regressor. In addition, inversion of the estimated inertia matrix is also avoided and the new design is free from end-point acceleration measurements. The dynamics of the robot manipulator is assumed that all of the matrices in robot model are unavailable. Since these matrices are time-varying and their variation bounds are not given, traditional adaptive or robust designs do not apply. The function approximation technique is used here to represent uncertainties in some finite linear combinations of the orthogonal basis. The dynamics of the output tracking can thus be proved to be a stable first order filter driven by function approximation errors. Using the Lyapunov stability theory, a set of update laws is derived to give closed loop stability with proper tracking performance. A 2 DOF planar robot with environment constraint is used in the computer simulations to test the efficacy of the proposed scheme.

Telehaptic Perception of Delayed Stiffness Using Adaptive Impedance Control: Experimental Psychophysical Analysis

2013 ◽  
Vol 22 (4) ◽  
pp. 323-344 ◽  
Author(s):  
Costas S. Tzafestas ◽  
Spyros Velanas
Keyword(s):  
Time Delays ◽  
Impedance Control ◽  
Human Perception ◽  
Superior Performance ◽  
Actual Performance ◽  
Control Scheme ◽  
Network Delays ◽  
Psychophysical Analysis ◽  
Remote Environment ◽  
Adaptive Impedance Control

Telehaptics is the science of transmitting touch-related sensations over computer networks. With respect to robot teleoperation, telehaptics emphasizes more on reliably reproducing physical properties of a remote environment, as mediated over a network through the use of appropriate haptic interfacing technologies. One of the main factors that can cause degradation of the quality of a telehaptic system is the presence of time delays. Inspired by concepts such as impedance-reflection and model-mediated telemanipulation, an adaptive impedance control scheme has been proposed aiming to mitigate some of the problems caused by network delays in a telehaptic system. This paper presents an experimental analysis, which has been conducted to assess the actual performance of the proposed telehaptic scheme in terms of both control and human perception objectives. Firstly, a set of comparative numerical experiments is presented aiming to analyze stability and characterize transparency of the telehaptic system under large time delays. The results show the superior performance of the proposed adaptive impedance scheme as compared to direct force-reflecting teleoperation. Then, a series of psychophysical experiments is described, to evaluate the performance of the telehaptic system with respect to human perception of remote (delayed) stiffness. An analysis of the obtained results shows that the proposed adaptive scheme significantly improves telehaptic perception of linear stiffness in the presence of network delays, maintaining perceptual thresholds close to the ones obtained in the case of direct, nondelayed stimuli. A comparative experimental evaluation of psychometric transparency confirms the superior robustness with regard to time delay of the adaptive impedance telehaptic scheme as compared to state-of-the-art position/force transparentizing methods.

A Novel Robust Model Reference Adaptive Impedance Control Scheme for an Active Transtibial Prosthesis

Robotica ◽  
2019 ◽  
Vol 37 (9) ◽  
pp. 1562-1581 ◽  
Author(s):  
Siamak Heidarzadeh ◽  
Mojtaba Sharifi ◽  
Hassan Salarieh ◽  
Aria Alasty
Keyword(s):  
Closed Loop ◽  
Impedance Control ◽  
Nonlinear Dynamic Model ◽  
Model Reference ◽  
Impedance Model ◽  
Prosthetic Foot ◽  
Robust Model ◽  
Asymptotic Tracking ◽  
Adaptive Impedance Control ◽  
Model Reference Adaptive

SummaryIn this paper, a novel robust model reference adaptive impedance control (RMRAIC) scheme is presented for an active transtibial ankle prosthesis. The controller makes the closed loop dynamics of the prosthesis similar to a reference impedance model and provides asymptotic tracking of the response trajectory of this impedance model. The interactions between human and prosthesis are taken into account by designing a second-order reference impedance model. The proposed controller is robust against parametric uncertainties in the nonlinear dynamic model of the prosthesis. Also, the controller has robustness against bounded uncertainties due to unavailable ground reaction forces and unmeasurable feedbacks of accelerations at the socket place. Moreover, an appropriate Series Elastic Actuator (SEA) mechanism for the prosthetic ankle is included in this work and its effects are discussed. Tracking performance and stability of the closed-loop system are proven via the Lyapunov stability analysis. Using simulations on an overall amputee prosthetic foot system, the effectiveness of the proposed RMRAIC controller is investigated for the task of level ground walking.

Adaptive impedance controller design for flexible-joint electrically-driven robots without computation of the regressor matrix

Robotica ◽  
2011 ◽  
Vol 30 (1) ◽  
pp. 133-144 ◽  
Author(s):  
Ming-Chih Chien ◽  
An-Chyau Huang
Keyword(s):  
Function Approximation ◽  
Controller Design ◽  
Impedance Control ◽  
Approximation Error ◽  
Approximation Technique ◽  
Actuator Dynamics ◽  
Electrically Driven Robots ◽  
Adaptive Control Strategy ◽  
Model Reference Adaptive ◽  
Fifth Order

SUMMARYTo the best of our knowledge, this is the first paper focus on the adaptive impedance control of robot manipulators with consideration of joint flexibility and actuator dynamics. Controller design for this problem is difficult because each joint of the robot has to be described by a fifth-order cascade differential equation. In this paper, a backstepping-like procedure incorporating the model reference adaptive control strategy is employed to construct the impedance controller. The function approximation technique is applied to estimate time-varying uncertainties in the system dynamics. The proposed control law is free from the calculation of the tedious regressor matrix, which is a significant simplification in implementation. Closed-loop stability and boundedness of internal signals are proved by the Lyapunov-like analysis with consideration of the function approximation error. Computer simulation results are presented to demonstrate the usefulness of the proposed scheme.

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