Online Control System Design for Selvedge Waste Length in Rapier Weaving Loom

Controlling the selvedge waste length in shuttle-less weaving loom has great importance in the cost of production. In this study, an online control system is designed and implemented in a weaving loom. First, a high-speed camera records selvedge formation in several successive cycles with different weft yarn tensions. Then the length of weft yarn waste is measured by three methods based on image processing, namely Kalman filter, K-means method and background subtraction. The performances of three methods in terms of accuracy and processing time are evaluated and compared with each other. The results show that Kalman filter method has higher accuracy and it requires lower processing time. In addition, it shows that the results obtained from two other methods are very close to the actual result. There is an inverse relationship between weft yarn tension and selvedge waste length. By increasing the yarn tension, waste length is decreased. Therefore, based on the online measurement of selvedge waste length, the waste length can be measured in each cycle and adjusted by changing the weft yarn tension. So the proposed system has satisfactory performance in online control of weft yarn waste.