1. Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong
2. Department of Systems Engineering, University of Saarland, Saarbrücken, Germany
3. Department of Mechanical Engineering, Harbin Institute of Technology, Weihai, China
4. Active Materials and Smart Living Laboratory, University of Nevada, Las Vegas, Las Vegas, NV, USA
5. School of Mechanical and Electrical Engineering, Hohai University, Changzhou, China