An autotuning controller for 2x2 interacting processes

An autotuning controller for a class of 2 X 2 interacting processes based on the pattern recognition technique is proposed. The autotuner uses the closed-loop process response patterns observed under multiloop interacting control with reference to their single-loop counterparts to obtain the desired tuning parameters. Customized identification techniques under both single-input single-output (SISO) and multi-input multi-output (MIMO) environments are developed for this application. The controller is tested for a range of 2-input 2-output multivariable processes that are characterized by the relative gain (RG) and relative dynamics. The time response of the autotuning controller is also compared favourably to that of the biggest log modulus tuning (BLT) method using the distillation column models proposed in the literature.