Application of explicit criterion minimization in adaptive control

Abstract

The explicit criterion minimization (ECM) algorithm for adaptive control is investigated. From an engineering point of view, a boundedness condition based on the incremental quantity of controller parameters, Δρ, is employed in the present study. It is found that successful operation is achieved by using control amplitude constraints rather than switching between an ECM and a pole-placement algorithm, as suggested by Trulsson. To reduce the effect of disturbances, an integral term is added to the controller. With these modifications the ECM algorithm is found to perform satisfactorily. The effect of different orders of the system model and controller is discussed for a varying dead-time control system. The application of ECM on the tuning parameters of a proportional-integral-derivative (PID) controller is also presented in the paper. The ECM algorithm was also evaluated by applying this algorithm in the experiment of a pilot scale coupled-tank liquid level control system.