1. School of Electronics and Information Engineering, Hebei University of Technology, 5340 Xiping Road, Tianjin 300401, P. R. China
2. State Key Laboratory of Reliability and Intelligence Electrical Equipment, Hebei University of Technology, Tianjin 300130, P. R. China
3. School of Mechanical Engineering and National Engineering Research Center for Technological Innovation Method and Tool, Hebei University of Technology, Tianjin 300401, P. R. China
4. State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China