1. Electric Power Research Institute of Guangxi Power Grid Co Ltd, Nanning, Guangxi 530000, China
2. School of Electrical and Information Engineering, Anhui University of Technology, Ma’an shan 243032, China
3. Research Institute of UAV, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
4. College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China