Dynamic matrix control of the lateral position of a moving web

The lateral motion of the web is one of the most common problems in roll-to-roll (R2R) systems, which results in degraded product quality, waste, or even processing interruption. An industrial proportional-integral-derivative (PID) controller with fixed gain is mostly used for lateral position control. In fact, the model parameters of the web lateral dynamics such as the tension and the transport velocity of the web are seldom exact. Variations of these parameters could significantly affect the lateral web dynamics. A dynamic matrix control (DMC) strategy is adopted in the offset pivot web guide to control the lateral position of the web, which does not depend on accurate model. Simulations of the DMC controller and the PID controller was carried out with a sinusoidal disturbance in different web conditions. The results show that DMC controller performs much better than PID controller with good disturbance rejection. It is observed that the lateral position of the DMC controller is less than a half of that of the PID controller. As the web velocity decreases or the web tension increases, the lateral position becomes smaller.