Research ArticleMultivariable design of improved linear quadratic regulation control for MIMO industrial processes

•A new state space model based linear quadratic control is proposed.•The design is applied to chamber pressure of an industrial coke furnace.•Improved closed-loop control performance is achieved under model/process mismatches.

In this study, a multivariable linear quadratic control system using a new state space structure was developed for the chamber pressure in the industrial coke furnace. Such processes typically have complex and nonlinear dynamic behavior, which causes the performance of controllers using conventional design and tuning to be poor or to require significant effort in practice. The process model is first treated into a new state space form and the implementation of linear quadratic control is designed using this new model structure. Performance in terms of regulatory/servo, disturbance rejection and measurement noise problems were all compared with the recent model predictive control strategy. Results revealed that the control system showed more robustness and improved the closed-loop process performance under model/process mismatches.