1. Zhao, C.: Ultrasonic Motors: Technologies and Applications. Springer, Heidelberg (2011)
2. Wang, Y., Wang, Z.: Finite element analysis of interfacial crack between the ultrasonic motor rotor and the friction material. Small Spec. Electr. Mach. 35(9), 13–15 (2008)
3. Zhang, S., Zhou, S., Zhao, C.: Simulation and experiment of crack propagation on simplified elastic composite beam from ultrasonic motor’s stator. Micromotor 44(8), 6–10 (2011)
4. Zhang, Y., Luo, Y., Qu, J.: Damage analysis of sator of ultrasonic motor based on extended finite element method. J. Mech. Strength 36(2), 267–672 (2014)
5. Chen, B., Li, H., An, G.: Degradation state recognition of ultrasonic motor based upon locality preserving projection and support vector machine optimized by fruit fly optimization algorithm. In: 2017 2nd International Conference on Power and Renewable Energy (ICPRE). IEEE (2017)