A Hybrid PID Controller for Flexible Joint Manipulator Based on State Observer and Singular Perturbation Approach

To resolve the problems concerning with vibration suppression and position tracking of flexible joint manipulator system without link velocities information, a hybrid PID controller based on singular perturbation and state observer is presented. In order to estimate the velocities of links, a state observer is adopted instead of extra speed sensors on the link side. Singular perturbation theory is employed to decouple the system into a fast subsystem and a slow subsystem. For the fast subsystem, a PD controller which can damp out the vibration of flexible joints is designed. For the slow subsystem, a hybrid PID controller is proposed to realize desired position tracking. The effectiveness of the proposed control scheme is illustrated by theoretical analysis and simulation results.