Extremum control for optimal operating point determination and set point optimization via sliding modes

In the design of a control system, it is often desirable to operate at the peak of an appropriate performance surface which characterizes the performa nce of the closed-loop operation. However, in many cases, only limited info rmation might be available on the plant and the desired performance criteri on which makes a priori determination of such an optimal operation mode dif ficult in the first place. The online identification of an optimal operatin g point and the development of a controller structure which enables the sys tem to robustly operate at such a point constitute a remarkable research pr oblem with this motivation. In this paper, a two-time scale sliding mode op timization method is studied for this purpose. The adopted scheme assumes a regulative controller which produces an equilibria for the closed-loop sys tem parametrized by a free control parameter and employs a sliding mode opt imization method to adapt this parameter in a slower time scale to increase the performance of the overall system. A simulation study is summarized to illustrate the approach. [S0022-0443(00)01004-2].