Joint tracking controller for multi-link flexible robot using disturbance observer and parameter adaptation scheme

Abstract

An improved composite controller of singular perturbation approach is designed for controlling a multi-link flexible robot with uncertainties. We adopt the standard form of a singular perturbation approach for modeling. To reduce the coupling effect from flexibility, the bandwidth of a slow subsystem is modulated by considering the fundamental frequency. The disturbance observer provides a means for defining the bandwidth of a slow subsystem as well as compensating disturbances. At the same time, uncertainties in the fast subsystem are updated to enhance the capability for vibration suppression in conjunction with PID (Proportional-integrative derivative) modal feedback. We draw conditions for Lyapunov stability of the modal feedback and adaptive scheme. A numerical simulation will support the validity of our research results. (C) 2002 Wiley Periodicals, Inc.