1. Ph.D. Candidate, School of Aeronautics, Northwestern Polytechnical Univ., Xi’an 710072, China.
2. Associate Professor, School of Aeronautics, Northwestern Polytechnical Univ., Xi’an 710072, China (corresponding author).
3. Associate Professor, State Key Laboratory for Mechanical Structural Strength and Vibration, Xi’an Jiaotong Univ., Xi’an 710049, China.
4. Professor, Unmanned System Research Institute, Northwestern Polytechnical Univ., Xi’an 710072, China.