Abstract
Self-tuning control schemes (STC) are useful for systems with unknown or slowly time-varying parameters. Some single-input/single-output PID control schemes based on STCs have been proposed for such systems. However, there are a lot of multivariable systems in real process industries. And these systems often have relatively large time-delays. In this paper, a design scheme of self-tuning PID control system is proposed for multivariable systems with unknown parameters and time-delays. The controlled object is equipped with an internal model in order to compensate the time-delay and also unstable zeros. Subsequently, a multivariable PID controller is designed for the augmented or compensated system. The PID parameters are calculated recursively based on the relationship between the mimimum variance control law and the PID control law. A simulation example is presented to demonstrate the effectiveness of the proposed scheme.
