1. State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical Engineering Zhejiang University Hangzhou 310027 China
2. First Affiliated Hospital of Zhejiang University School of Medicine Zhejiang University Hangzhou 310027 China
3. School of Engineering University of Glasgow Glasgow G12 8LT UK
4. Automation Technology ABB Corporate Research Sweden Vasteras 72178 Sweden