T型直线超声波电动机的运行机理及其特性分析

摘要

A novel T-shaped linear ultrasonic motor was proposed.The d31 mode of the PZT was used to excite the bimorph cantilever beams to generate a longitudinal vibration,which can push the slider to move in a straight line with the friction force between the driving feet and the slider.The general structure and operating principle of the new motor were introduced at first.Then the stator of the T-shaped linear ultrasonic motor was modeled with the finite element method (FEM),and the force transferring model of the contact surface between the stator and the slider was established based on the impulse theorem and the force equilibrium law.With this model,simulations on the speed-thrust characteristics under different pre-load were performed,and the validity of the model was testified by the experimental results.Experimental results show that when the motor is excited by a voltage with peak-peak amplitude of 200 V and frequency of 23.75 kHz,the no-load speed of the motor reaches 250 mm·s-1 when the pre-load is 50 N,and the maximum thrust reaches 7.6 N when the pre-load is 200 N.%提出了一种新型T型直线超声波电动机,利用PZT d31模式激发压电双晶悬臂梁产生纵向振动,并通过驱动足与滑条间的摩擦作用带动滑条作直线运动.研究了电动机结构和运行机理,采用有限元方法对T型直线超声波电动机定子进行了建模和分析;利用冲量定理和力平衡原理建立电动机定子和滑条接触面力传递模型,仿真分析了不同预压力作用下电动机的速度-推力输出特性,实验验证了仿真分析结构的正确性.实验结果表明,在激励电压幅值Vpp为200 V和激励频率为23.75 kHz作用下,电动机在预压力为50 N时的空载直线速度达到250 mm ·s-1,在预压力为200 N时的最大推力达到7.6N.