1. Department of Mechanical EngineeringThe University of Hong KongHong Kong
2. School of Automation, Image Processing and Intelligent Control Key Laboratory of Education Ministry of China, Huazhong University of Science and TechnologyLuoyu Road 1037Wuhan430074People's Republic of China
3. National Center for Mathematics and Interdisciplinary Sciences, Chinese Academy of SciencesBeijing100090People's Republic of China