Design of Decentralized Repetitive Control of Linear MIMO System

This paper proposes decentralized repetitive control (RC) design for multiple inputs multiple outputs (MIMO) system. The design comprises in both continuous and discrete-time domain. A decentralized stabilizing controller is firstly developed in continuous-time to achieve a desired complimentary sensitivity function. Relative Gain Array (RGA) analysis is used to obtain the best pairings of inputs and outputs. Then, robustness analysis is conducted to determine the impact of neglected couplings. Secondly, the RC is designed in discrete-time based on the information of complimentary sensitivity function. A set of low order, stable and causal repetitive control compensators are developed using a new frequency domain method. The proposed RC compensator works for both minimum and non-minimum phase system. Simulation results for linear MIMO model of pick and place robot arm are presented to validate the effectiveness of the design.