Adaptive Control of Teleoperation Systems with Uncertainties: A Survey

2021 ◽  
Author(s):  
Chang Liu
Keyword(s):  
Adaptive Control ◽  
Teleoperation Systems

Bilateral Adaptive Control of Nonlinear Teleoperation Systems With Uncertain Dynamics and Dead-Zone

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Xia Liu ◽  
Mahdi Tavakoli
Keyword(s):  
Adaptive Control ◽  
Function Analysis ◽  
Dead Zone ◽  
Adaptive Controller ◽  
Bilateral Control ◽  
Uncertain Dynamics ◽  
Teleoperation System ◽  
Control Scheme ◽  
Teleoperation Systems ◽  
Dynamic Uncertainties

Dead-zone is one of the most common hard nonlinearities ubiquitous in master–slave teleoperation systems, particularly in the slave robot joints. However, adaptive control techniques applied in teleoperation systems usually deal with dynamic uncertainty but ignore the presence of dead-zone. Dead-zone has the potential to remarkably deteriorate the transparency of a teleoperation system in the sense of position and force tracking performance or even destabilizing the system if not compensated for in the control scheme. In this paper, an adaptive bilateral control scheme is proposed for nonlinear teleoperation systems in the presence of both uncertain dynamics and dead-zone. An adaptive controller is designed for the master robot with dynamic uncertainties and the other is developed for the slave robot with both dynamic uncertainties and unknown dead-zone. The two controllers are incorporated into the four-channel bilateral teleoperation control framework to achieve transparency. The transparency and stability of the closed-loop teleoperation system is studied via a Lyapunov function analysis. Comparisons with the conventional adaptive control which merely deal with dynamic uncertainties in the simulations demonstrate the validity of the proposed approach.

scholarly journals Adaptive Control of Teleoperation Systems With Linearly and Nonlinearly Parameterized Dynamic Uncertainties

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Xia Liu ◽  
Mahdi Tavakoli
Keyword(s):  
Adaptive Control ◽  
Function Analysis ◽  
Tracking Errors ◽  
Adaptive Controllers ◽  
Control Framework ◽  
Control Scheme ◽  
Force Tracking ◽  
Nonlinearly Parameterized ◽  
Teleoperation Systems ◽  
Dynamic Uncertainties

Existing work concerning adaptive control of uncertain teleoperation systems only deals with linearly parameterized (LP) dynamic uncertainties. Typical teleoperation system dynamics, however, also posses terms with nonlinearly parameterized (NLP) structures. An example of such terms is friction, which is ubiquitous in the joints of the master and slave robots of practical teleoperation systems. Uncertainties in the NLP dynamic terms may lead to significant position and force tracking errors if not compensated for in the control scheme. In this paper, adaptive controllers are designed for the master and slave robots with both LP and NLP dynamic uncertainties. Next, these controllers are incorporated into the 4-channel bilateral teleoperation control framework to achieve transparency. Then, transparency of the overall teleoperation is studied via a Lyapunov function analysis. Simulation studies demonstrate the effectiveness of the proposed adaptive scheme when exact knowledge of the LP and NLP dynamics is unavailable.

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