Improved delay-dependent stability criteria for telerobotic systems with time-varying delays

This paper addresses the synchronization problem of telerobotic systems, in which the master and slave robots are assumed to be serial manipulators and the communication-delays are assumed to be time-varying and nonsymmetric with known lower and upper bounds. Proportional derivative, proportional, and position-force control structures are considered for passive and nonpassive human operator. Using the Lyapunov-Krasovskii methodology, delay-dependent stability conditions of the closed-loop system are established in the form of linear matrix inequalities. The stability criteria derived in this paper is shown to be less conservative than some of the existing results within the literature, and they amend the calculation of the control parameters and ensure the stability and transparency of the system for larger bounds of communication-delays. Simulation studies are performed to demonstrate the effectiveness of the proposed stability criteria in obtaining a larger stability region for the system.