Robust H∞ Computed torque Control for Manipulators

Abstract

This paper aims at addressing the synthesis application of robust control technique in a manipulator based on LMIs (Linear Matrix Inequalities) in order to minimize the H_∞ norm by taking into account the uncertain parameters of the manipulator. The control strategy is based on the compute torque control scheme that is composed of two control loops. The inner loop aims at linearizing the nonlinear robot dynamics using feedback linearization. The outer loop tracks the desired trajectory based on a PD controller, which is robustified against uncertain parameters and neglecting dynamics. The robust control technique is applied in a two degrees of freedom planar manipulator and the numerical results show the benefits of the robustified control strategy in the dynamical performance in terms of tracking accuracy, disturbance rejection and uncertain parameters.