Printhead carriage transport high speed control system with robust compensator

A robust controller has been developed for print-head carriage transportation. The controller consists of a linear-quadratic Gaussian (LQG) controller and a robust compensator. Applying LQG control, a print-head carriage transport velocity of about 1.2 m/sec without vibrations was achieved. The acceleration and deceleration areas were within 30 mm. However, compensation with only LQG control has problems regarding deterioration in the control, resulting from environmental variations and aging. The proposed robust compensator prevented the deterioration in control results by cancelling the equivalent disturbance, which corresponds to the environmental variations and aging. Moreover, the optimal controller configuration was composed by using a discrete design for the robust compensator. According to the experimental results, the velocity response errors from the reference, in case of the robust controller, were within 5%, even if the motor temperature changed from 20°C to about 60°C. Employing the robust controller, a dot serial printer, whose printing speed is 495 characters per second in pica printing mode, has been developed