Robust Stability of a Modified Clarke-Gawthrop Self-Tuning Controller

Abstract

In the paper, the Clarke-Gawthrop type self-tuning controller is modified and shown to be robust stable with respect to unmodeled plant uncertainties and bounded disturbances. The self-tuning controller is proposed here by the two steps: the first, an optimal control law i5 derived by means of minimizing a quadratic cost function of the Clarke-Gawthrop type; the second, the optimal control law is modified by introducing an estimate of the modeling error as a feedback. The robustness results are derived by neither requiring too much a priori knowledge of the plant parameters, nor using any assumptions on the adaptive signals.