Deadtime Compensation-Based Approximate Decoupling Control Approach for Multivariable Processes

The interaction effects among individual loops and multiple time delays are the prime reasons for degrading the closed-loop performance of multivariable systems. For highly interacting systems, decouplers are used to counteract interaction effects. However, decouplers may not be realizable and even if they are realizable, for high dimensional systems, decoupler elements may be complex. To improve the decoupler realizability, a dead-time compensation (DTC) approach is proposed in this work. The DTC framework can minimise the impact of dead-time on system dynamics. The proposed decoupler is designed based on the dynamic relative gain array (DRGA) to compensate for interaction effects. The DRGA reveals more insights about the coupling effect between a pair of input-output loops. The DRGA elements are used as decoupler elements for the multivariable process. The minimization of both interaction effects and dead-time dynamics can be achieved with the proposed DTC-based decoupling control approach. The simple IM C PI tuning rules are utilized to implement controllers for each loop. The simulation study affirming the proposed method provides better desired closed-loop performance, error indices for nominal and plant model mismatches, and robust stability against plant uncertainty over the popular existing decoupler based approaches.