1. State Key Laboratory of Mechanic Transmission, Chongqing University 400044 Chongqing, China, College of Opto-Electronic Engineering, Key Lab of Optoelectronic Technology and System of Education Ministry, Chongqing University, Chongqing, China,
2. College of Opto-Electronic Engineering, Key Lab of Optoelectronic Technology and System of Education Ministry, Chongqing University, Chongqing, China
3. Automatic College of Chongqing University, 400044 Chongqing, China