High-acceleration and high-precision point-to-point motion control based on disturbance observer with improved Q-filter

Abstract

Under conditions of high acceleration, high-precision and fast positioning of point-to-point motions with short strokes is restricted by the internal and external disturbances occurring in the motion process. To address this issue, a disturbance observer-based control scheme is employed here to suppress the disturbances, which combines a feedforward controller and a feedback controller. Since the low-pass filter of disturbance observer (Q-filter) determines the disturbance suppression ability after the nominal model has been identified, the Q-filter design becomes the most important consideration in practical control. In this article, an improved Q-filter is proposed to further suppress the disturbances by canceling the resonance peak of the binomial filter. High-acceleration point-to-point motions are conducted on a linear-driving stage and the experimental results demonstrate that the proposed control scheme is capable of achieving high-precision and fast positioning control. Since the improved Q-filter exhibits superior disturbance suppression ability, the positioning time with positioning error of 2 µm has been shortened from 13.1 to 11.4 ms.