Multivariable inverse decoupling PID control for the flatness and thickness of 4-high aluminum cold rolling mill

A new inverse decoupling control scheme to the main diagonal decoupling target is introduced for flatness and thickness system with the features of strong coupling, uncertainty and time delays in aluminum tandem rolling process. The flatness and thickness dynamic coupling model is built, and the inverse decoupling theory is used to decouple the MIMO system to weaken the coupling effects, and then analyzed the stability of the inverse decoupling matrix. A PID controller is designed by combining DDE (Desired Dynamic Equation) method for system uncertainty of dynamic model parameter perturbation and external disturbance. Simulation of field data shows the effectiveness of the algorithm for the coupling system.