中文摘要：

介绍了超声波电动机的优势及特殊的应用背景,指出多自由度是该领域的研究热点。介绍了多种结构类型的多自由度球形超声波电动机及其特点,针对球形电机高精度控制的要求,综述了电机姿态检测和运动控制的研究现状,对比分析了不同测控方法的优点与不足,并指出下一步研究及应用的方向。

英文摘要：

The advantages and special applic, ation background of ultrasonic motor were described, and multi-degree-of -freedom（M-DOF） was research hotspot. Various structures of M-DOF spherical ultrasonic motors were introduced. In order to met the high-precision control requirements of spherical motor, the research status of attitude detection and motion control were summarized. On the basis of comparative analysis of the advantages and disadvantages of different methods, the direction of future research and application were put forward.