E-mail addresses: cuiym03@aliyun.com (Y. Cui), Cui Yanmei received the M.S. degree in mechanical engineering from Tsinghua University in 2006, is a Ph.D. student at the School of Mechanical Engineering, Northwestern Polytechnical University. Her main research interests are mechanical transmission, piezoelectric ceramic drive. Corresponding author. Tel.: + 86 29 88493958. E-mail addresses:fauto@nwpu. edu.cn (Z. Fang). Fang Zongde is a professor and Ph.D. supervisor at the School of Mechanical Engineering, Northwestern Polytechnical University. His area of research includes mechanical transmission, vehicle design, and bionic machinery.