Tension control improvement in automatic stator in-slot winding machines using iterative learning control

Conventional motor winding machines use a passive device such as a dancer arm or hysteresis brake to adjust the tension of the wire. However, when the winding speed increases, the passive device may not be able to react quickly enough so that a sudden change in the tension will likely cause the enameled wire to vibrate. Consequently, the motor winding quality will be affected. In order to cope with this difficulty, instead of using a passive device, this paper proposes an active tension control scheme, in which the wire tension measured by a load cell is used as the feedback signal of the tension control loop. Moreover, feedforward control and iterative learning control are integrated into the proposed tension control scheme to improve system response and suppress the periodic disturbance arising from the winding process. Several motor winding experiments have been conducted to assess the performance of the proposed approach.