1. College of Electrical and Information Engineering, Lanzhou University of Technology, Lanzhou, China
2. Key Laboratory of Gansu Advanced Control for Industrial Processes, Lanzhou University of Technology, Lanzhou, China
3. National Demonstration Center for Experimental Electrical and Control Engineering Education, Lanzhou University of Technology, Lanzhou, China
4. College of Computer and Communication, Lanzhou University of Technology, Lanzhou, China