1. State Key Laboratory for Manufacturing Systems Engineering, Research Institute of Diagnostics and Cybernetics, Xi’an Jiaotong University, Xi’an 710049, China;
2. Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI 48109-2140 e-mail:
3. State Key Laboratory for Manufacturing Systems Engineering, Research Institute of Diagnostics and Cybernetics, Xi’an Jiaotong University, Xi’an 710049, China