A New Asymptotic Tracking Approach for Robot Manipulators with Actuator Saturation

This paper revisits the asymptotic tracking of robot manipulators with actuator constraints. Different from the existing control methods, the proposed saturated control algorithm is developed based on a proportional- derivative (PD) feedback control scheme with computed feedforward of robot dynamics. The benefit of the developed design approach is that it offers a new bound to shape the actuator signal that is less conservative than bounds specified by previously developed saturated control schemes, hence allowing more freedom to design the feedback gains for the given actuator constraints. Lyapunov's direct method is used to prove semi-global asymptotic stability. Simulations performed on a two-degree-offreedom (DOF) manipulator are provided to illustrate the effectiveness and improved performance of the proposed approach.