Adaptive control of uncertain nonlinear teleoperation systems

Abstract

Kinematic parameters of a robotic manipulator are hard to measure precisely and the varying size and shape of tools held by the robot end-effector introduce further kinematic uncertainties.Moreover, the exact knowledge of the robot nonlinear dynamics may be unavailable due to model uncertainties. While adaptive master-slave teleoperation control strategies in the literature consider the dynamic uncertainties in the master and the slave robots, they stop short of accounting for the robots' kinematic uncertainties, which can undermine the transparency of the teleoperation system. In this paper, for a teleoperation system that is both dynamically and kinematically uncertain, we propose novel nonlinear adaptive controllers that require neither the exact knowledge of the kinematics of the master and the slave nor the dynamics of the master, the slave, the human operator, and the environment. Therefore, the proposed controllers can provide the master and slave robots with a high degree of flexibility in dealing with unforeseen changes and uncertainties in their kinematics and dynamics. A Lyapunov function analysis is conducted to mathematically prove the stability and master-slave asymptotic position tracking. The validity of the theoretical results is verified through simulations as well as experiments on a bilateral teleoperation test-bed of rehabilitation robots.

Towards robot‐assisted anchor deployment in beating‐heart mitral valve surgery

“…The matrices have the following properties: Property 1. The matrix M x , i ( θ i ) is symmetric and positive definite. Property 2.…”

Patient-Robot-Therapist Collaboration Using Resistive Impedance Controlled Tele-Robotic Systems Subjected to Time Delays

“…Considering the subscripts i m  and i s  for the master and slave, respectively, the robots' dynamic matrices and vectors have the following properties [27,43,44]:…”

“…In order to perform complex therapy exercises, however, nonlinear multi-DOF systems are needed. With the purpose of position synchronization between the nonlinear master and slave robots, some adaptive bilateral control strategies [24][25][26][27] have been suggested in recent years. For simultaneous position tracking and force reflection, nonlinear adaptive position-force control methods [28][29][30] have been proposed.…”

Impedance control of non‐linear multi‐DOF teleoperation systems with time delay: absolute stability

“…Also, the convergence of the master and slave trajectories to their desired impedance model responses is proven in a Lyapunov framework. Note that in the previous bilateral position and force tracking controllers [17, 18, 34] for non‐linear systems, only the tracking error convergence to zero was proven and the absolute stability was not guaranteed in the presence of communication delays. It should be mentioned that the absolute stability of a two‐port network guarantees the stability of the coupled system connected to two passive terminations [35].…”