A Longitudinal-Bending Hybrid Linear Ultrasonic Motor and Its Driving Characteristic

As a new type of driver, linear ultrasonic motor (LUSM) is widely used in the high-tech field because of its low speed, high thrust, low noise, and no electromagnetic interference. However, as an actuator used in microdevices, most of the existing LUSMs are large in size and not compact in structure. In order to overcome these limitations, a new structure of linear ultrasonic motor’s stator is developed in this paper. The stator is similar to a tuning fork structure, which is divided into three parts: two driving feet, two driving legs, and the driving body. By using the first-order longitudinal vibration mode of the whole stator and the unique partial second-order bending vibration mode of the driving legs to achieve vibration mode degeneracy, a mode hybrid linear ultrasonic motor that is easy to miniaturize is proposed. Its working principle is analyzed. The dynamic analysis of the stator is carried out by using finite element software. The structure dimension of the stator and the driving frequency under the working mode are determined. At the same time, the feasibility of driving feet synthesizing elliptical motion is verified theoretically and experimentally. In addition, the LUSM test setup is built. The effects of driving frequency and Vpp on stator stall force and average velocity are studied. The results show that the maximum stall force can reach 99 mN, and the average velocity of the motor is 88.67 mm/s with Vpp = 320 V and driving frequency 80.2 kHz. The proposed LUSM is appropriate for use in occasions with quick return characteristics, like the controlling valve or nozzle of the printer. The research results provide guidance for the stator design of the linear ultrasonic motor.

A Brief Review on the Recent Evolution in Piezoelectric Linear Ultrasonic Motors

This article represents the various recent advancements in the field of Piezoelectric Ultrasonic Motors especially in linear type. The construction and operation principles evolving time to time. We have accumulated and presented a brief discussion on the linear ultrasonic motor including its working principles, initial designs and recent advancements in this article. These motors have had increasing applications in recent years and have been developing rapidly due to its simplicity of construction and good performance. The potential applications are expanding lately to various areas such as medical devices, precise positioning systems, astronautical devices, tactile feedback systems, and many more. Owing to the wide range of applications, simple and compact design, rapidly increasing miniaturization, and the several advantages of the linear ultrasonic motor, it has been a vastly researched area in the last few decades. More and more effort is being put into creating smaller and efficient designs, structures and materials of the device, with stable and upgraded output performance, and acceptable range of frictional wear enabling prolonged usage.

Modeling and validation of preload force effect on characteristics of a V-shaped linear ultrasonic motor

The traditional dynamic models of linear ultrasonic motor (LUSM) do not consider the influences of the preload force and the roughness of the contact surface of stator/slider on the performance of the motor, which unable to effectively describe the dynamic behavior of the motor. In this paper, a dynamic model is established for a V-shaped LUSM considering the influence of the preload force and the roughness of the contact surface of stator/slider on the dynamic behavior of the motor. The contact mechanism of the stator/slider and the influence of preload force on the stator parameters are studied and analyzed. The effectiveness of the developed model is verified by comparing with the analytical model that ignored the effect of the preload force on the stator parameters. The experimental results shown that the developed model can accurately reflect the dynamic characteristics of the motor, and the model will be helpful for the function prediction and precise control of the motor.

A Compact Linear Ultrasonic Motor Composed by Double Flexural Vibrator

A minimized linear ultrasonic motor was proposed, and two flexural bimorph vibrators were utilized to form its stator. The construction of the linear ultrasonic motor and its operation principle was introduced. Two working modes with the same local deformation distribution were chosen on the basis of Finite Element Analysis (FEA). To obtain its optimized structural parameters, sensitivities on frequency difference were calculated, and a way of decreasing the frequency difference of two working modes was introduced. A prototype of the optimized model was made. The modal testing of the stator and its performance evaluation was conducted. The modal testing results were in good agreement with that of the simulation. The maximum speed of the prototype is 245 mm/s, and its maximum thrust is 1.6 N.