1. Laboratory of Intelligent Control and Robotics; Shanghai University of Engineering Science; Shanghai 201620 China
2. Department of Electrical and Computer Engineering; Texas A&M University; College Station 77843 TX USA
3. School of Automation, Image Processing and Intelligent Control Key Laboratory of Education Ministry of China; Huazhong University of Science and Technology; Wuhan 430074 China
4. College of Electronics, Information Engineering; Tongji University; Shanghai 200092 China