1. School of Electrical and Information Engineering, Xihua University, Chengdu 610096, China
2. School of Applied Mathematics, University of Electronic Science and Technology of China, Chengdu 610054, China
3. School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide SA 5005, Australia
4. School of Engineering and Science, Victoria University, Melbourne, VIC 8001, Australia
5. Department of Engineering, Faculty of Engineering and Science, University of Agder, 4898 Grimstad, Norway
6. School of Automation, Chongqing University, Chongqing 400044, China