Improvement of printing accuracy via web handling control in multi-colors printing machines

Web handling is an important issue in printing machine for improving the performance of printing products. In the multi-colors printing machine which is consist of multi-printing units, the dynamics of each unit are coupled and the signal propagation is always with delay. This paper presents a delay-dependent nonlinear control approach for a three colors printing machine. First, a nonlinear coordinate change is proposed for the state variables that describe the dynamics of the tension and the printing error. Then, based on the new coordinates, a delay-dependent feedback law is designed such that the closed loop system converges to zero. Finally, some simulation results will be demonstrated to compare with the conventional control method.