Globally stable dual-mode control of robots

Decoupled nonlinear robot controllers are designed via Lyapunov or passivity-based techniques. The global asymptotic stability of the final position in point-to-point motions is proved for position-velocity (PD) controllers, taking into account actuator bounds, and also for nonlinear three-term (PID) controllers with no limitation of the controller outputs. This suggests a dual-mode control where integration of the error signal is interrupted during controller saturation. Tests on an industrial robot show the performance of such control systems. (C) 1998 IFAC.