A new indirect adaptive control scheme for time-varying plants

Structures are developed for the control and estimation parts of the indirect adaptive scheme which are more appropriate for time-varying plants. In contrast to the usual pointwise schemes, the new controller structure can meet the control objective exactly for a wide class of plants with smooth but otherwise unrestricted parameter variations. On the other hand, the possibly available knowledge of the form or frequency of variation of the fast parameters is included in the new estimator structure so that, for successful estimation, the overall plant is not restricted to varying slowly with time. The new estimator and control law are combined using the certainty equivalence principle to develop an indirect adaptive control scheme meeting the control objective for plants with time-varying parameters whose fast varying parts are of known form and unknown parts are slow in the mean