Model Reference Adaptive Tension Control of Web Packaging Material

Web tension control in packaging machinery is crucial to ensure product quality. This paper presents a mathematical model of tension on base of dynamic analysis for the typical transport system, and analyzes the primary factors which bring tension change. Because the traditional PI controller is ineffective to adjust the tension when the radius of the unwinding roll is getting smaller, a model reference adaptive PI controller is proposed to improve the system performance. The reference model is given by a mathematical formula, and adaptive control laws for controller parameters are established with gradient method. The performance of the control system is tested through computer simulation. The results show that the dynamic performance and stability of the system are improved significantly, and tension is controlled and maintained at an appropriate level.