[1]Center for Robotics, University of Electronic Science and Technology of China, Chengdu 611731, China;
[2]School of Mathematical Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China;
[3]School of Automation, University of Electronic Science and Technology of China, Chengdu 611731, China;
[4]School of Automation and Electrical Engineering, University of Science and Technology Beijing, Beijing 100083, China;