1. Shenzhen International Graduate School, Tsinghua University, Shenzhen, China.
2. Tencent Robotics X, Tencent, Shenzhen, China.
3. Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen, China.
4. State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing, China.