1. School of Mechanical Engineering; Xi'an Jiaotong University; Xi'an China
2. Shaanxi Key Laboratory of Mechanical Product Quality Assurance and Diagnostics; Xi'an Jiaotong University; Xi'an China
3. College of Engineering; Swansea University, Bay Campus; Fabian Way, Crymlyn Burrows Swansea SA1 8EN UK
4. State Key Laboratory for Manufacturing Systems Engineering; Xi'an Jiaotong University; Xi'an China