PD Output Feedback Control Design for Industrial Robotic Manipulators

This paper presents an output feedback proportional--derivative (PD)-type controller for the trajectory tracking control of robotic manipulators. In the first part of the paper, we propose a PD-like output-feedback control law. The design comprises a PD term with nominal robot dynamics, where the unknown velocity signals are estimated from the output of the linear estimator. Using Lyapunov analysis, we characterize the asymptotic property of all the signals in the closed-loop error model dynamics. This property sets the bound on the tracking error trajectory of the closed-loop system. In the second part, we remove the nominal model dynamics from the control design to formulate a model-independent PD-type output feedback approach. Using an asymptotic analysis for the singularly perturbed closed-loop model, we guarantee that all the signals under the proposed PD output feedback design are bounded and their bounds can be made arbitrarily small by using observer-controller gains. Implementation of results demonstrate the potential application of the proposed method on real systems.