1. Department of Mechanical and Energy Engineering, Shenzhen Key Laboratory of Biomimetic Robotics and Intelligent Systems and Guangdong Provincial Key Laboratory of Human Augmentation and Rehabilitation Robotics in Universities, Southern University of Science and Technology, Shenzhen, China
2. Department of Mechanical Engineering, Tsinghua University, Beijing, China
3. Department of Mechanical Engineering, The University of British Columbia, Vancouver, BC, Canada