Adaptive Control with Discontinuous Forgetting Factor and Saturation for Improved Robustness

An adaptive control law is proposed to improve the robustness of the adaptive system with respect to fast unmodeled dynamics represented by a singular perturbation. The new law is based on saturation of the regressor and control parameter vector with inclusion of a discontinuous forgetting factor. The analysis of the resulting system is presented and the conclusions are illustrated by simulations. Advantages of this extension are related with global stability and better transient behavior.