PIDF control for high order MIMO system based on coupling compensation

Abstract

Complex systems, considered in control engineering, are often modeled in the form of a multi-input-multi-output (MIMO) coupled model. These systems pose definite challenges, due to their coupling behavior and the associated high computational costs. This paper describes a proposal for a technique for designing proportional-integral-derivative plus filter (PIDF) controllers for high order MIMO systems, while compensating the inherited coupling effect. The high-order MIMO system is decoupled into single-input-single- output (SISO) subsystems, which are then investigated by analyzing their time and frequency responses, pole-zero maps, and closed-loop stability. PIDF controllers with phase lead compensators are designed for each subsystem model so as to satisfy the desired closed-loop specifications. Additional controllers are introduced in order to eliminate the coupling effects in the coupled control system, while respecting the physical constraints. The proposed technique is validated through numerical simulations on a coupled control system with a high-order MIMO model, which demonstrate that the proposed approach can achieve the control requirements with acceptable performance for various reference inputs.