Winding control using pseudo-derivative feedback

This work examines the winding of film from one free reel to a driven reel using both a pseudo-derivative feedback (PDF) and a proportional-integral-derivative (PID)-controlled servomotor. Measurements are compared with a theoretical model simulated with Simulink®. In this work, only the velocity of the film was controlled after measurement with an optical encoder; tension in the film was not controlled. The measurements and control were executed on a personal computer using LabVIEW®. Overall both controllers could cope with the range of full and empty reels for a demand velocity step of 1 m/s but the PDF controller could cope with a demand for 2 m/s. Rise times of less than 500 ms were obtained for both controllers with the best PID controller faster at around 130 ms. The motor current required for the PDF controller was less than that for the PID system. Tension forces were, as predicted, higher with PID control; therefore the overall steady state average error was zero for both controllers. The results show that the rise time differences to achieve steady state in the case when opposite spools were full were less for the PID controller.