1. Department of Mechanical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208;
2. The State Key Lab of Fluid Power Transmission and Control, Zhejiang University, Hangzhou 310027, China e-mail:
3. Department of Mechanical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 e-mail:
4. Fellow ASME Department of Mechanical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 e-mail:
5. Departament d′Enginyeria Mecánica, Universitat Politècnica de Catalunya, Balaguer Vilanova i la Geltrú. 08800, Spain e-mail:
6. State Key Laboratory of Ultra-Precision Machining Technology, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR 999077, China e-mail: