Active Compensation of Flexibility in Belt-Driven Drive Trains

This paper discusses a novel method to compensate the eeects of exibil-ity in belt-driven drive trains. Such drives are found in robot manipulators, for example, where drive exibility is undesirable. In some situations, band-width limitations can make exibility diicult to compensate using the primary actuator. In others, the control for the primary actuator is pre-deened and cannot be easily altered. We have introduced a second actuator, called a dancer, which applies a force to the belt at a point between the pulleys. Using backstepping to control belt tension with the dancer, the system transfer function from input pulley to output pulley can be made exactly rigid. The performance of the dancer-actuated system compares favourably with a composite controller designed for the original belt drive.