Sliding mode position/force control for motion synchronization of a flexible-joint manipulator system with time delay

A robust adaptive control strategy based on a sliding mode is designed for the motion synchronization of multiple flexible-joint robotic manipulators system with time delay. First, synchronization motion of the system is considered as constraint conditions and is simplified to the position/force control. Then the time delay is considered as a first-order and compensated by the controller. By utilizing a sliding mode consisting of position error and force error, an adaptive controller based on back stepping is designed to drive the closed-loop system states to reach the adopted sliding model surface, thus can guarantee the asymptotic convergence of the position error and force error. For uncertainties of the manipulator parameters, joint stiffness and actuator inertia, an adaptive control law and robust control is applied to the online parameter estimation and bound compensation respectively. Finally, the simulation results show the feasibility of the proposed method.