A generalized design of decoupling multivariable control for disturbance rejection

In this paper, a systematic procedure is proposed for the generalized design of decoupling multivariable controller, which may result in a complete decoupling, partial decoupling or no decoupling, to achieve a better disturbance rejection response. Before the decoupling, a relative load gain (abbr. RLG) is defined to determine which control loops need to be decoupled and which control loops don't. By a transitional design matrix and its adjoint matrix, a completely or partially inverse-based multi-input-multioutput (MIMO) decoupler with generalized form is presented to decouple the process into the specified open-loop process. This decoupled open-loop process is further decomposed into several equivalent singleloop systems, equivalent open-loop processes and disturbances. Finally, the controller can be synthesized based on each equivalent system for disturbance rejection. Stability robustness of the system is tuned with measures for the modeling errors in the decoupled open-loop process. Simulation examples are illustrated to show that this proposed method is effective for disturbance rejection in MIMO systems.