Model based PD control during the speed-up phase in roll-to-roll web register systems

Roll-to-roll web systems are widely used in modern industries, and register control is very important for product quality. This paper discusses the dynamic analysis and control of the register error in the speed-up phase. Based on the constant speed mathematical model, a mechanical model with undetermined coefficients is built and the coefficients are identified by the practical open-loop error curves acquired during speed-up process. Based on the model, a speed variation compensation PD control is proposed to eliminate the nondeterministic disturbance of the tension variation in speed-up process. The simulation shows that the proposed model based method is feasible and the accuracy of register control is improved.