单振子二自由度球面马达的运动机理

Motion Mechanism of Two-Degree-of-Freedom Spherical Motor Using Single PZT Vibrator

利用矩形板形压电振子的两种振动模态,构建了一种采用单片压电振子驱动球形转子,形成两个旋转自由度的压电球面超声马达,对马达的作用机理进行了仿真分析和试验验证.利用有限元法对马达的矩形板压电振子的振动模态、共振频率进行了分析计算,仿真结果表明矩形板压电振子能够形成振型清晰的B32和B23振动模态,模态频率分别为49.127 kHz和49.756 kHz.对压电振子上每个凸起与球形转子之间的接触点的运动轨迹进行了计算机仿真,并对仿真结果进行了试验验证.分析结果表明各接触点能有效形成时序合理的椭圆运动轨迹,作为支撑足的一组凸起的变形量占作为驱动足的一组凸起的变形量的30%,能够用于驱动球形转子形成二自由度转动.仿真分析和试验结果证明了二自由度球面马达球形转子形成二维运动的作用机理.

A two-degree-of-freedom piezoelectric spherical ultrasonic motor using only one piezoelectric element to drive the rotator was proposed based on two vibration modes of a rectangular plate type piezo￣electric vibrator.The motion mechanism of the motor was verified by simulation and experiment.The vibration modes and resonance frequencies of the motor＇s plate type piezoelectric vibrator were calculated by finite element method.The simulation results show that the piezoelectric vibrator can produce clear vibration shapes in B32 and B23 modes,and their modal frequencies are 49.127 kHz and 49.756 kHz,respectively.The motion trajectories of four contact points between the protrusion and the spherical rotor were analyzed with computer simulation,and prototype test was carried out to verify the simulation results.The results indicate that the four contact points can form elliptical trajectories with reasonable timing,which can be used to drive the spherical rotor to form rotation with two-degree-of-freedom,and the deformation of protrusions which act as support feet is 30% of that of protrusions that act as drive feet.The simulation and experimental results confirm the formation of two-dimensional motion mechanism of the two-degree-of-freedom spherical motor.