行波型杆式超声电机模态频率调节

Modal Frequency Adjustment of a Traveling Wave Type Rod Shape Ultrasonic Motor

加工好的兰杰文振子型杆式超声电机其两相弯振模态频率往往会不一致,这将会影响电机的效率、输出性能以及运行的稳定性。针对该问题,提出一种在电机定子装配好的状态下对其模态频率进行调节的方法。通过定子的动力学方程和K.A.Stetson结构摄动理论,求解出修改后定子的模态频率,找到了调节两相模态频率的方法。对定子进行有限元分析,找到了定子修改的合适位置,并分析了在这些位置上进行定子修改对两相模态频率的影响。制作了定子样机,对修改前后的定子模态频率进行了测试,两相弯振模态频率之差由原来的170Hz调整到70Hz,达到了工程上的要求。从试验上验证了该文的理论和有限元分析结果。

As far as a bolted Langevin-type rod shape ultrasonic motor is concerned,the modal frequencies of two bending vibration modes usually disagree with each other. As a result,motor efficiency,performance and speed stability are affected. A modal frequency adjustment technique was proposed to solve this problem. According to dynamic equations of the stator and the K. A. Stetson＇s structural perturbation theory,the modal frequencies of the updated stator were calculated. Finite element analysis of the stator was employed to determine the stator appropriate position for modification. Meanwhile,the influence of stator modification on the bending vibration modal frequency was analyzed. A stator prototype was fabricated and its frequency magnitude characteristic was tested. The modal frequency difference of two phases was 170 Hz. After chamfered portions had been formed on the stator,the difference was reduced to 70 Hz,which met the requirements of the engineering project. The validity of the proposed method is verified using experimentation.