[1] Northwestern Univ, Dept Mech Engn, 2145 Sheridan Rd, Evanston, IL 60208 USA
[2] Zhejiang Univ, State Key Lab Fluid Power Transmiss & Control, Hangzhou 310027, Peoples R China
[3] Univ Politecn Cataluna, Dept Engn Mecan, Balaguer Vilanova I Gelt 08800, Spain
[4] Hong Kong Polytech Univ, Dept Ind & Syst Engn, State Key Lab Ultra Precis Machining Technol, Kowloon 999077, Hong Kong, Peoples R China