On-line tuning of PI/Lead compensators for decoupling multivariable processes with specifications on phase and bandwidth

In this paper, an on-line identification and auto-tuning method is proposed for multivariable processes. Systematic identifying procedures and on-line tuning rules are developed for computing parameters of proportional plus integration and Lead compensators. The performance of the compensated systems can be evaluated by wanted bandwidth, phase margins and low-interacting characteristics. No iteration for finding parameters of compensator is needed. Parameters of PI/Lead compensator can be retuned if they are needed. Three numerical examples give the proposed method provides better performance, robustness and less interaction effects than those of other mentioned on-line computing methods.