1. School of Electrical Engineering; North China University of Science and Technology; Tangshan Hebei 063009 People's Republic of China
2. Department of Mechanical and Manufacturing Engineering; University of Calgary; Calgary Alberta T2N 1N4 Canada
3. School of Automation Engineering; University of Science and Technology Beijing; Haidian Beijing 100083 People's Republic of China
4. School of Mechanical Engineering; Yangtze University; Jingzhou Hubei 434023 People's Republic of China