Robustness Analysis of decoupled PID controller for Paper Machine Headbox

A Particle Swarm Optimisation (PSO) based PID controller has been proposed in this paper for a paper machine headbox. The considered headbox model has been perturbed and the proposed controller has been implemented on the perturbed model to assess the robustness of the system. The robustness of the proposed controller has been evaluated on the basis of sensitivity and complementary sensitivity functions. Sensitivity and complementary sensitivity functions provide significant insight into the system's behavior for disturbance, uncertainties, and noise (due to sensors/actuators). Hence, the controller to be designed for a given system should be concerned about these functions. Apart from these functions, worst-case sensitivity analysis has also been carried out for the perturbed headbox. The responses obtained from the proposed controller have been compared with some conventional PID tuning techniques and it is observed that the proposed controller yields better robustness.