Accurate control of ball screw drives using pole-placement vibration damping and a novel trajectory prefilter

This paper presents a pole-placement technique to achieve active vibration damping, as well as high bandwidth disturbance rejection and positioning, in ball screw drives. The pole-placement approach is simple and effective, with an intuitive physical interpretation, which makes the tuning process straightforward in comparison to existing controllers which actively compensate for structural vibrations. The tracking performance of the drive is improved through feedforward control using inverted plant dynamics and a novel trajectory prefilter. The prefilter is designed to remove tracking error artifacts correlated to the velocity, acceleration, jerk and snap (fourth derivative) of the commanded trajectory. By applying the least-squares method to the data from a single tracking experiment, the prefilter can be tuned quickly and reliably. The proposed controller has been compared to the P-PI position-velocity cascade controller commonly used in industry. The controller design, stability analysis and experimental results are discussed in the paper.