Abstract: To maintain tension on a fiber tow as it travels between a spool of the tow and a fiber placement head in a computer controlled fiber placement machine, closed tension loop servo control tow velocity feed forward is provided to control spool rotation so as to not only provide closed loop tension control but to also cause rotation in anticipation of expected tow movement such as due to tow payout upon commanded movements of the fiber placement head. Gain scheduling based on spool radius is also provided. Additionally, a compliant roller is provided to reduce tension dips and spikes from disturbances on the tow, and an inner velocity loop is included with the closed tension loop to provide more effective control of tow tension. The servo control is reconfigurable into an open or pseudo-closed loop mode with a safety low power supply to slowly reel-up slack tow after tow threading, for example, and to otherwise maintain low tension on the tow to hold it in the machine while allowing servicing thereof.

Abstract: Servo spool control for tape web positioning is disclosed wherein the position of the web between two spools may be accurately known and controlled and the tension on the web maintained. To accomplish such control, the motors driving the respective spools are driven by dynamic torque signals in response to change in position commands from a computer controller wherein the dynamic torque signals are correlated to the inertial torque and frictional torque of the spools and their drives.