V形大推力直线超声电机定子振动的有限元分析

Finite Element Method Analysis of the Stator of a V-Shaped Linear Ultrasonic Motor with Large Thrust

为适应需要大推力的直线超声电机的应用场合,提出了一种具有双变幅杆的V形电机。电机主要包括定子和动子两部分。定子由互相垂直、头部相连的两个兰杰文振子组成,它们完全对称且具有相同的一阶纵振模态。两个一阶纵振模态合成并通过定子和动子之间的摩擦作用,驱动动子作直线运动。为了获得较大推力,将V形电机定子设计成具有一定锥度的变幅杆。电机定子的结构参数对其动态特性有着重要的影响,用有限元法计算了不同结构参数对电机定子的一阶纵振频率和头部振幅的影响,计算了电机定子的一阶纵振频率和头部振幅对结构参数的灵敏度。建立定子优化模型来获得头部较大振幅以及具有合适的工作频率。参考灵敏度分析结果,设置设计变量时,灵敏度较大的结构参数变化范围设置较大些,以增大定子头部振幅为目标函数。根据仿真结果研制了电机样品并进行了性能实验,当激励电压的峰-峰值V_(p-p)=300 V、工作频率f=27.3 kHz时,电机的最大输出推力接近40 N,最高输出速度为100 mm/s,电机的输出性能呈现出低速、大推力的特点。

For the development of ultrasonic linear motor with large thrust,a V-shape motor with dual horns was proposed. The motor has a stator and a slider. The stator consists of two orthogonal Langevin vibrators which are joined together in their ends. The Langevin actuators are symmetrical and have same first order longitudinal mode. A linear motion of the slider is genera- ted by friction between the stator and the slider when the two first order longitudinal modes are combined. The stator is de- signed with a taper horn to obtain larger thrust. The structure parameters of the stator have a very significant impact on the dynamic characteristics. The modal frequency and the head＇s vibration amplitude sensitivities of the stator to all structural parameters were calculated. The optimum model was established to amplify the bead＇s vibration amplitude and get rational work frequency. According the results of the upper sensitivities analysis the structural parameters which have an important on the working modal frequency and the head＇s vibration amplitude were selected as design variables which have larger variation range. The important judgment parameter amplifying the head＇s vibration amplitude of the stator was used as the objective function. The motor was designed and made based on the theoretical analysis. When exciting voltage peak-peak value Fp-p=300 V, working frequency f= 27.3 kHz, the maximum driving force of the motor approaches 40 N, and the maximum velocity of the motor is about 100 mm/s. So the motor output properties have characteristics of slower velocity and stronger force.