A modified generalised minimum-variance stochastic self-tuning controller with pole-zero placement

Abstract

The paper proposes a modified robust self-tuning controller, which minimises a cost function, incorporating system input, system output and set-point. It provides an adaptive mechanism which ensures that both the closed-loop poles and zeros are placed at their pre-specified positions. The proposed design overcomes the shortcomings of other designs by combining the robustness of classical control strategy of pole-zero placement with the flexibility of self-tuning generalised minimum variance control. It tracks set-point changes with the desired speed of response, penalises the excessive control action, and can be applied to non-minimum phase systems and unstable systems. Besides, at steady state, the controller has the ability to regulate the constant load disturbance to zero. Example simulation results using both simulated and real plant models demonstrate the effectiveness of the proposed controller.