中文摘要：

分析目前超声波电动机定子工作模态设计试验方法的不足；分析非线性系统频率响应特征；分析非线性系统隐含于线性调频激励响应中的非线性信息，指出在超声波电动机定子特征频率分析中引入时频联合分析方法的优越性。在所开发的超声波电动机面内振动测试系统中，用时频分析方法获取定子线性调频激励下的振动响应时频谱，可以方便快速地揭示定子的特征频率和定子的非线性信息，为判定超声波电动机定子是否存在非线性特性从而为合适工作模态的快速确定提供科学依据。

英文摘要：

The shortage of the design test of the working modal frequency of the stator of ultrasonic motors is analyzed. Nonlinear property of the stator of ultra-sonic motors （USMs） and its frequency response property is analyzed. Hidden information of nonlinear property of the stator of USMs in the vibration response signal when excited with linear frequency modulated signal is analyzed. Points out that it is excellent to introduce time-frequency analysis theory to analyze the characteristic frequency of the stator of USMs. In developed in-plane vibration test system for USMs, using the time-frequency distribution spectrum got through time-frequency analysis of the vibration signal of the stator of USMs excited with linear frequency modulated sine wave, can quickly and conveniently uncover the information of the nonlinearity and characteristic frequency. The application example testifies that the means is efficient and feasible. And a scientific gist is provided to ascertain the fit working modal frequency of the stator of USMs.