Precise tension control of a dancer with a reduced-order observer for roll-to-roll manufacturing systems

Precise tension control is critical to guaranteeing the specific functionality and topography of printed layers from roll-to-roll (R2R) printing systems. This is because the tension disturbance of substrate affects the surface energy, which determines the geometry of a printed circuit. Dancer systems are used to attenuate tension disturbances by the motion of the dancer roll. The angle of the dancer rod is measured by a potentiometer, and feedback control with an adjacent driven roller is used to maintain the dancer roll in an equilibrium position. However, the dynamic tension regulation of the dancer has not been verified through a dynamic analysis on the position of the dancer roll and tension disturbance. In this study, a mathematical model of the dancer was summarized, and the dynamic characteristics were analyzed to investigate the motion of the dancer roll and tension. The tension regulation performance was found to deteriorate in the certain frequency range. Because the dynamic response of dancer position does not correlate well with the tension; particularly magnitude difference between tension and dancer position began to increase in bode plot. So, a well-known reduced-order observer was employed to estimate and control the tension disturbance over a wide frequency range.