1. State Key Laboratory of Mechanical TransmissionsChongqing University Chongqing 400044 China
2. College of Materials Science and EngineeringChongqing University Chongqing 400044 China
3. SDU RoboticsThe Maersk Mc‐Kinney Moller InstituteUniversity of Southern Denmark Odense DK‐5230 Denmark
4. SoftLab, Bristol Robotics LaboratoryUniversity of Bristol Bristol BS8 1QU UK