Control of a Multimode Piezomotor With the Prestressing Force Automatically Adjusting

Piezomotors play a crucial role in precision engineering due to their unique qualities such as nanometer-scale resolution, millimeter-scale stroke, and inherent self-locking feature when power is cut off. Motion mode, prestressing force, and driving signal all have a significant impact on the motion performance of a piezomotor. This article presents a technique for controlling a multimode piezomotor by regulating prestressing force and switching motion modes, allowing the motor to perform optimally in terms of accuracy and velocity. A theoretical model of motion characteristics and motion failure analysis was developed. The relationship between the control variables and the motion characteristics was investigated using numerical simulation. Based on the results, a mode switching strategy was devised, with each motion mode is controlled using PID arithmetic. Experiment studies validated the feasibility of the proposed technique, with the piezomotor achieving a point-to-point accuracy of 0.25 
μ
m and a tracking error of 2.5%. The relationship between the axial load force and the velocity was investigated. In terms of load and velocity, the results revealed that the multimode is preferable to single mode. The proposed technique is flexible and expandable to a wide range of multimode piezomotor-based devices.