System and method for controlling the strain of web material

摘要

A system and method for controlling the strain of a web material supplied to a machine by adjusting a tension force applied to the web material. An operator defines a target web strain via an input device. A speed sensor senses the speed of the web material supplied to the machine at a first position and a second position and generates a speed signal representative of the difference. A tension sensor senses a tension force applied to the web prior to the first position and after the first position and generates a tension signal representative of the difference. A control system calculates web strain as a function of the tension signal and speed signal, and compares the calculated strain with the target web strain and generates a speed control signal as a function of the comparison. The feed device is responsive to the speed control signal for adjusting a speed differential of the web to adjust tension force applied to the web.