An Adaptive Control Referring to the Desired Complementary Sensitivity Function

Abstract

It is effective for robust control design to evaluate complementary sensitivity function if the uncertainty of a controlled object is known. The conventional adaptive control with parameter estimation provides satisfactory control performance against parameter variation but it is not sufficiently robust against unstructured uncertainty. In this paper, we propose a combined adaptive control design referring to parameter estimation against parameter variation and complementary sensitivity function against unstructured uncertainty. The proposed method includes initial estimation of uncertainties using plant input and output, and its stability is proved for an overall adaptive system. The advantage of this design is that initial adjustment of parameters in control law needs little tuning. Experiments and simulations for an oil hydraulic system are performed to verify the effectiveness.