Spinline tension control in melt spinning by discrete adaptive sliding-mode controllers

The spinline tension plays a critical role in the development of fiber structures and the quality of as-spun yarns in melt spinning. Implementing a controller to adjust the spinline velocity is helpful to maintain the spinline tension at a target level with small fluctuation, enabling as-spun yarns to possess the desired tenacity and uniform qualities. The spinline tension system is difficult to model and the stochastic disturbance always exists. The discrete adaptive sliding-mode controller can robustly and adaptively deal with the system with the unknown model and stochastic disturbance, such as the spinline tension system. The algorithm estimates the parameters of the controller in the sense of minimizing the deviation from the sliding surface, thus reducing the variation of the tension response about the desired level. The sliding surface is defined by an asymptotically stable polynomial, and seven stable polynomials are chosen in experiments. The experiments are carried out by using a laboratory type of the melt spinning setup to produce polypropylene as-spun yarns. Compared with the results without control, the proposed controller can not only maintain the mean of the tension response close to the target level but also reduce the standard deviation to the value, which is generally acceptable to the manufacturer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3816–3821, 2006