Robust Controller Design for Nonlinear Teleoperation System Using Passivity-based Scheme

This paper presents a novel scheme for robust controller design for teleoperation system; there are parametric uncertainties in nonlinear model and varying time-delay in the communication channel, and robots are in contact with non-passive human operator and environment. First, the structure of nonlinear control law is designed for nominal system utilizing the Passivity Based Control (PBC) scheme. Then, using the Lyapunov-Krasovskii (LK) theorem, sufficient conditions are derived for robust asymptotic stability of system in terms of matrix inequalities to tune controller parameters. Also, by definition of an appropriate performance criterion, controller parameters are obtained to minimize the position tracking errors besides guaranteed robust stability. The contributions of the proposed method are twofold. First, the developed controller is fixed-structure which can be implemented easily in practice. Second, the asymptotic stability of system is assured without any requirement for existence of passive part in the dynamical model of non-passive interaction forces. Simulation results of 3-dof teleoperation system are compared to a rival method to demonstrate the advantages of the suggested method.