1. State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, China
2. School of Mechanical Engineering, Hunan University of Science and Technology, Xiangtan, Hunan, China
3. School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan, Hubei, China
4. State Key Laboratory of Offshore Wind Power Equipment and Efficient Utilization of Wind Energy, Harbin Electric Corporation Wind Power Company Ltd., Xiangtan, Hunan, China