Dual motor position feedback control for electrically preloaded rack-and-pinion drive systems to increase accuracy

To increase the accuracy of indirect position-controlled dual motor rack-and-pinion drives, a new approach is being proposed that uses the encoders of both motors on a test bench. By electrically preloading these motors, backlash does not occur simultaneously in both drive trains. Continuous contact between the pinion and rack and thus force-transmission to the table is ensured, by switching away from the signal with backlash. Backlash is therefore eliminated from the control loop and the system accuracy without direct table position sensing can be increased. Experiments show that the tracking error is reduced by 59 % compared to indirect control.