多自由度超声波电机及其转子支持机构研究

Research on a multi-degree-of-freedom ultrasonic motor and the holding mechanisim of the rotor

应用有限元方法,设计和制作了一种能实现机器关节的多自由度超声电机.给出了一种正交轴承法转子支持机构,用于实现转子在机器手指关节中的应用.该电机定子由一个压电多层纵振子和一个夹心式弯曲振动换能器组成.多层振子较低电压下可在竖直方向产生较大振动位移.夹心式弯曲振子由两个纵向振动压电片和四个铜电极组成.在夹心振子上施加具有一定相位差的电压信号,会产生两个相互正交的弯曲振动.通过激励定子3种不同振动模式,可驱动位于定子表面的转子产生多自由度转动.测试结果表明:以多自由度超声电机作为驱动源,采用正交轴承法转子支持机构,可以有效增加机器手指关节的运动自由度.

To design and fabricate a robot finger joint based on a hybrid multi-Degree-of-Freedom（multi-DOF） piezoelectric ultrasonic motor.The motor′s stator consists of a multi-layered piezoelectric longitudinal vibrator and a sandwich bending vibrator.The multi-layered vibrator can produce large longitudinal vibration displacement in the z-direction at low driving voltage.The sandwich vibrator is composed of two lead zirconate titanate rings and four-divided bronze electrodes,and is driven by phased voltages to excite the bending vibration in two orthogonal directions.The synthesis of the longitudinal and bending vibrations can make a ball rotor rotate in three directions.An orthogonal bearing holding mechanism is introduced to hold the ball rotor without preventing the multi-DOF motions of the robot finger joint.The motions of the finger are demonstrated and evaluated experimentally.