1. School of Mechanical and Electronical Engineering, East China Jiaotong University, Nanchang, P.R. China
2. The State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou, P.R. China
3. School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW, Australia