| In this dissertation an indirect adaptive control algorithm is presented, which can be applied to linear time-invariant systems as well as to linear time-varying systems with rapidly varying parameters. This algorithm does not require persistent excitation. A key feature of this algorithm is the use of an assumed structure of parameter variations which enables it to cover a wide class of linear systems.; A modification of the least squares algorithm is used for the parameter estimation, which has a dead zone to handle robustness to the unmodelled plant uncertainties or external disturbances. A forgetting factor is introduced in the algorithm to aid in the tracking of time-varying parameters. The forgetting factor used is based on the constant information principle. The control law used is due to Kleinman. The advantage of this method is that it can be applied to linear time-varying plants with reachability index greater than the system order n as well as to the plants with reachability index equal to n.; With this control law and a state observer, all based on the parameter estimates, it is shown that the resulting closed-loop system is robustly globally stable. As a design example, the proposed algorithm is applied to the design of the normal acceleration controller of missiles with rapidly changing parameters. Excellent performance is demonstrated by the proposed algorithm. |
