Robust adaptive nonlinear control with transient performance specifications

The results presented in this paper are twofold: a new class of adaptive controllers is verified on practicability and with the new controllers is endeavored to remove some of the shortcomings of the control of the XY-table in the past. Theoretical bounds for the new adaptive control schemes, referred to as tuning functions design, indicate strong transient performance. So far little is known about the robustness of the controllers. The robustness of two controllers, respectively based on state feedback and output feedback, is verified with simulations and experiments performed for the XY-table. Controllers based on state feedback showed very good results, as well in simulations as in experiments. The controller could easily be implemented and tuning of the control parameters appeared quite easy. The controller removed some of the shortcomings occurring in the past. Controllers based on output feedback appeared more difficult to implement. In simulations an undesirable behaviour on initial errors was observed. Therefore two extensions on the original control scheme were proposed. Both extensions resulted in more freedom in the controller design. In experiments the range of possible tunings was restricted due to numerical problems. In the allowable range the results of the controller were inferior to the results obtained with the state feedback controller. The controller did not confirm the expectation of achieving improvement by merging the design of an estimator and of an adaptive controller.