Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084, China;
Department of Helicopter Mechanical Engineering, Institute of Army Aviation, Beijing 101123, China;
Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084, China;
Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084, China;
Department of Precision Instruments and Mechanology, Tsinghua University, Beijing 100084, China;