Optimization strategy of tension control for film changing based on feedforward control

Tension control is one of the core elements of the control system of film bi-directional stretching production line, which directly determines the film quality. For the upper winding type double station winding turret equipment with auxiliary roll, during the process of roll change operation, the change of film tension caused by turret overturning will adversely affect the quality of finished film. For this reason, a feed-forward speed compensation strategy is proposed in this paper. By calculating the two superimposed velocities generated on the film by the turret overturning during the roll change operation, the strategy obtains a generalized formula for the superimposed velocities of the duplex winding turret with auxiliary roll. Through data analysis, the relationship between the rotation angle of the turret and the stacked acceleration was obtained. Based on the calculated relation equation of superimposed acceleration, a feed-forward-PID tension control system was designed and compared with the traditional PID controller in simulation experiments. The results show that the system has good control effect.