Based On H_ ¡Þ Robust Control Gravure Printing Machine Tension Control System

Tension control is a very important part of process control in printing and packing industry. Good tension control improves product quality and productivity. The tension change affects the processed material greatly. Excessive tension will lead the distortion or fracture of the material while too small tension makes the stress distortion layer by layer and affects the processing quality. Frequent tension change will lead the linear velocity and the degree of tightness change, and it will also bring the low productivity of qualified products. Main subjects discussed in this dissertation focus on the tension control of the gravure printing machine.The tension control system of the gravure printing machine has the characteristics of great dynamic change, strong coupling between linear velocity and tension, and many sources of disturbance. The tension among machines is coupling too. The tension in any place will lead to tension fluctuation in other places. Therefore it is difficult to control tension and the traditional PID control can't meet the requirements of tension. How to achieve better stability of tension control is the main contents of this dissertation.Based on Hook's law and the principle of torque balance, this paper sets up the mathematical model of the gravure printing machine tension control system. According to the characteristics of the tension control system, this paper proposes H_∞robust control method of tension control. The simulation results show that H_∞robust control has better performance than the traditional PID control. The tension control system is able to overcome the effects of outside interference and achieve a stable tension control.