基于半功率带宽法的行波超声电机谐响应分析

该文以本单位研制的中空行波超声电机定子为对象,进行了有限元建模及谐响应仿真,发现定子阻尼比的设置对仿真结果的准确性影响较大。通过多普勒激光测振系统测得定子模态参数,利用半功率带宽法求出定子模态阻尼比,代入模型后仿真跟实测结果基本吻合,工作模态B_(011)频率仿真误差为1.66%,振幅仿真误差为4.61%。将定子齿特征参数化,分析了齿距和齿高对定子模态的影响。根据低转速、大扭矩的电机设计目标选取了合适的齿参数,加工出新定子实物。基于同样阻尼比再次进行有限元仿真并对新定子进行激光测振,对比得到工作模态B_(011)频率仿真误差为0.62%,振幅仿真误差为1.94%,验证了有限元谐响应仿真的准确性。此外,对原定子和新定子组装的电机进行性能测试,后者最高空载转速降低了30%,堵转扭矩提升了20%,符合预期设计。准确的参数化有限元模型有助于促进超声电机的快速化设计,提高了对符合电机目标功能的设计参数的选择效率。

Analysis of the Harmonic Response of Traveling wave Ultrasonic Motor Based on Half power Bandwidth Method

In this paper, the finite element modeling and harmonic response simulation of the stator of the hollow traveling wave ultrasonic motor (TRUM H) developed by our laboratory are carried out. It is found that the setting of the damping ratio of the stator has a great influence on the accuracy of the simulation results. The modal parameters of the stator are measured by the Doppler laser vibration measurement system, and the modal damping ratio of the stator is calculated by the half power bandwidth method. The simulation results are basically consistent with the measured results after substituting the model. The frequency simulation error and the amplitude simulation error of B011 working mode are 1.66% and 4.61% respectively. The stator teeth characteristics are parameterized, and the influences of the pitch and tooth height on the stator mode are analyzed. According to the design goal of motor with low speed and high torque, the suitable teeth parameters are selected and a new stator is fabricated. The finite element simulation based on the same damping ratio is performed again and the laser vibration measurement of the new stator is carried out. By comparison, the frequency simulation error and amplitude simulation error of B011 working mode are 0.62% and 1.94% respectively, which verify the accuracy of the finite element harmonic response simulation. In addition, the performance tests of two motors assembled from the original stator and the new stator are carried out. The maximum no load speed of the new one is decreased by 30%, while the stall torque is increased by 20%, which are in line with the expected design. The accurate parametric finite element model is helpful to speed up the design of ultrasonic motor and improve the efficiency of the selection of design parameters that meet the target function of the motor.