Nonlinear disturbance observer based adaptive control for nonlinear teleoperation systems

In this paper, the stability and tracking control problem of a task space nonlinear bilateral teleoperation system is addressed interacting with a unknown environment. The controllers consist of adaptive controller and nonlinear disturbance observer to deal with uncertain dynamic model of manipulators, environmental and operators forces, respectively, in the presence of time delay. In order to estimate the uncertain parameters, the adaptation law is formulated. A lyapanov function is employed to prove stability of closed-loop system and tracking properties of position, velocity. Simulations are presented to validate the theoretical development of this paper.