Design and implementation of weft density feedback control system on weaving loom

Weft density has been considered as one of the most effective factors on woven fabric construction and it is influenced physical and mechanical fabric properties. Therefore, we developed a closed loop control system in a weaving machine. The manipulator element was take-up roller rotation speed. The weft density was measured by means of a special computational image processing routine. The PID control algorithm used to calculate the desired modification of take-up speed. However, the existing variable delay on the sensing weft density variation by the measuring system causes the conventional PID control system to have been disabled in providing robust action, so the control system was utilized by the Smith predictor to modify control behavior. To adjust control parameters, the function of the weaving machine has been investigated and a simulated model of the weaving process was constructed. The result of set point tracing and regulatory control in various tests indicated satisfactory performance of our new system.