MATERIAL ADVANCE TRACKING SYSTEM

摘要

The friction drive system (10) for printing, plotting or cutting graphic images on strip material (12) includes a feedback for a drive motor (40) driving a plurality of friction wheels (34, 36) for advancing strip material (12) in a longitudinal direction. The feedback signal comprises a short-term response component and a long-term response component to accurately pinpoint the exact longitudinal location of the strip material (12). The short-term response component is generated by comparing a motor encoder signal from a motor encoder (44) secured to the drive motor (40) with a commanded longitudinal position of the strip material (12) and passing the resultant differential error signal through an all pass filter (78). The long-term response component is generated by comparing a detecting encoder signal from a detecting encoder (54) secured to a device detecting the actual longitudinal position of the strip material (12) with the commanded longitudinal position of the strip material (12) and passing the differential error signal through a low pass filter (76).