A Globally Stable PD-INP-D Regulator for Robot Manipulators

This paper deals with the position control of rigid robot manipulators with uncertain payload. Proposed is a simple class of robot regulators consisting of a linear proportional-derivative (PD) feedback plus an integral action driven by an NP-D controller. By using Lyapunovpsilas direct method and LaSallepsilas invariance principle, the simple explicit conditions on the regulator gains to ensure global asymptotic stability are provided. The theoretical analysis and simulation results show that: an attractive feature of our scheme is that PD-I^NP-D controller has the faster convergence, better flexibility and stronger robustness with respect to uncertain payload, and then the optimum response can be achieved by a set of control parameters in the whole control domain of interest, even under the case that the payload is changed abruptly.