1. Softalink, LLC, Kearny, NJ 07032 e-mail:
2. Department of Biomechatronics Engineering, National Pingtung University of Science and Technology, Shuefu Road, Neipu, Pingtung 91201, Taiwan e-mail:
3. Department of Mechanical and Industrial Engineering, New Jersey Institute of Technology, Newark, NJ 07102 e-mail: