This paper deals with the position control of robot manipulators with uncertain payload. Proposed is a simple class of robot regulators consisting of a linear PD plus an integral action driven by PD controller. By using Lyapunovpsilas direct method and LaSallepsilas invariance principle, the simple explicit conditions on the regulator gains to ensure semiglobal asymptotic stability are provided. The theoretical analysis and simulation results show that: an attractive feature of our scheme is that PD-IPD controller has 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, even under the case that the payload is changed abruptly.