Research on the mechanism and control methods of mechanical drift in linear ultrasonic motors

Abstract

Linear ultrasonic motors (LUMs) have advantages such as de-energized self locking and-micro-nano displacement resolution. However, the presence of mechanical drift negatively affects their positioning and control accuracy, thereby limiting their application in ultra-precision fields. The mechanism of mechanical drift in the motor is currently unclear. In this study, we initially employ the Burgers model for the stator’s clamp and consider the internal friction and stick-slip effects of the slider, enabling the establishment of a non-autonomous dynamic model of the LUM. This model serves as a tool to delve into the mechanism causing mechanical drift. Subsequently, using this established dynamic model, we investigate how the LUM's structural parameters influence mechanical drift and seek methods to mitigate this undesirable phenomenon. Finally, we validate the model's validity and analyze the effects of different clamps on mechanical drift through experimental research. The research findings reveal that the mechanical drift in the LUM is primarily due to structural creep, with the clamp playing a pivotal role in driving the drift. Increasing the tangential stiffness of the clamp component and slider internal friction prove to be effective approaches to reducing mechanical drift. This study holds substantial theoretical and practical significance as it deepens understanding of the mechanisms of mechanical drift in LUMs and offers a pathway to achieve effective drift control.