Controller performance assessment based on minimum and open-loop output variance

The need to achieve reliable and effective automatic control systems has di rected numerous research efforts towards the development of monitoring and assessment methods of the closed-loop performance. A new controller assessm ent index, called relative variance index (RVI) is introduced in this work, according to which the closed-loop performance is compared with the best t heoretical control action (minimum valiance control) and no control action. For the estimation of RVI, an identification method is employed to extract the system models and an estimate of the process unit delays. The proposed index, RVI, is in agreement with the classical deterministic closed-loop a ssessment measures and thus can be utilized for the controller performance evaluation more effectively. (C) 2000 Elsevier Science Ltd. All rights rese rved.