Robust Tuning of Low-Order Controllers via Uncertainty Model ldentification

摘要

A tuning method for a controller of given structure is proposed, with particular emphasis on low-order compensators. The method consists of the processing of experimental results and prior information on the plant to be controlled, in order to obtain a plant uncertainty model, composed of a nominal model and a bounded perturbation representing the model- ling erron. The number of poles and zeros of the controller being fixed, a procedure is described which allows one to obtain the so-called robust Q set. This is the set of the controller parameter values for which the desired closed-loop performance specipcations are satisfied, whatever plant is con- sidered within the previously estimated uncertainly model. Given a designed controller, the worst-case performances, i.e. the performances that can be guaranteed for all systems belonging to the uncer- tainly model, are derived. This way the designer can tune the controller parameters to suitably bal- ance the closed-loop performances. Moreover, the performances guaranteed by applying the designed compensator to the actual plant can be evaluated.