1. Department of Mechanical Engineering Tsinghua University Beijing 100084 China
2. State Key Laboratory of Tribology Beijing 100084 China
3. Beijing Key Lab of Precision/Ultra‐Precision Manufacturing Equipment and Control Beijing 100084 China
4. Department of Electronic Engineering Tsinghua University Beijing 100084 China
5. Department of Engineering Mechanics Xi'an Jiaotong University Xi'an 710049 China
6. Tencent Robotics X Lab Shenzhen 518057 China