Time-optimal tension control for processing plants with continuous moving webs

Increasing the processing speed of production plants with continuous moving webs is the primary means for achieving higher cost-effectiveness. Upgrades of the mechanical part of the plant are costly compared to changes in controller software or even hardware. Therefore, the control algorithm should exploit by all means the maximum performance of the actuators. To prevent increased mechanical wear, the control concept must take into account the constraints given by the individual components as well. Time-optimal control in the classical sense cannot fulfil these requirements. In this paper, the authors describe two subsequently developed methods for fulfilling both needs with time-suboptimal control in the classical sense. Their applicability to real-world systems is demonstrated by test results. For further improvement, the application of receding horizon feedback control for processing plants with continuous moving webs is described and proposed.