Adaptive-observer-based robust control for a time-delayed teleoperation system with scaled four-channel architecture

Robotica ◽  
2021 ◽  
pp. 1-21
Author(s):  
Linping Chan ◽  
Qingqing Huang ◽  
Ping Wang
Keyword(s):  
Lyapunov Functional ◽  
Adaptive Observer ◽  
System Stability ◽  
Time Varying ◽  
Model Uncertainties ◽  
Control Approach ◽  
Time Varying Delay ◽  
Teleoperation System ◽  
Teleoperation Systems ◽  
Varying Delay

Abstract This article presents an innovative adaptive-observer-based scaled four-channel (4-CH) control approach applying damping injection for nonlinear teleoperation systems, which unify the study of robotic dynamic uncertainties, operator/environment force acquirements and asymmetric time-varying delays in the same framework. First, a scaled 4-CH scheme with damping injection is developed to handle time-varying delay while guaranteeing the passivity of communication channels. Then, the improved extended active observer (IEAOB) is deployed to derive the operator/environment force while addressing the issues of measurement noise and model uncertainties. Furthermore, the system stability is analyzed by choosing Lyapunov functional. Finally, the proposed method is validated through simulation.

scholarly journals A New Method for Bilateral Teleoperation Passivity under Varying Time Delays

2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Farzad Hashemzadeh ◽  
Iraj Hassanzadeh ◽  
Mahdi Tavakoli ◽  
Ghasem Alizadeh
Keyword(s):  
Time Delays ◽  
Communication Channel ◽  
Time Varying ◽  
Constant Delay ◽  
Time Varying Delay ◽  
Teleoperation System ◽  
Virtual Time ◽  
Varying Delay ◽  
Disturbance Estimator

A new framework is proposed to mitigate the adverse effect of time-varying time delays on the passivity of a teleoperation system. To this end, the communication channel with time-varying delays is modeled as a constant-delay channel along with additive output disturbances. Then, disturbance estimator blocks are added in each of the feedforward and feedback paths to estimate these disturbances and to compensate for them. In the disturbance estimator block, there is a need for a virtual time-varying delay block such that the overall communication channel can be seen as one with a constant delay. We also propose a method for determining this virtual delay. Two PHANToM haptic devices connected through a communication channel with time-varying delays are considered for a case study. Simulation and experimental results confirm the efficiency of the proposed method in terms of passivating the teleoperation system in the presence of time-varying delays.

Asymptotic stabilization of stochastic high-order upper-triangular nonlinear systems with input time-varying delay

2016 ◽  
Vol 39 (12) ◽  
pp. 1898-1905 ◽  
Author(s):  
Liang Liu ◽  
Yifan Zhang
Keyword(s):  
Nonlinear Systems ◽  
State Feedback ◽  
High Order ◽  
Feedback Stabilization ◽  
System Stability ◽  
Time Varying ◽  
Independent State ◽  
Time Varying Delay ◽  
Input Time ◽  
Varying Delay

Based on the homogeneous domination approach and stochastic nonlinear time-delay system stability criterion, this paper investigates the global state-feedback stabilization problem for a class of stochastic high-order upper-triangular nonlinear systems with input time-varying delay. By skilfully choosing an appropriate Lyapunov–Krasoviskii functional and successfully solving several troublesome obstacles in the design and analysis procedure, a delay-independent state-feedback controller is designed to render the closed-loop system globally asymptotically stable in probability. The simulation example is given to verify the effectiveness of the proposed design scheme.

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