1. Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China and Beijing Key Lab of Precision/Ultra‐Precision Manufacturing Equipments and Control, Tsinghua University, Beijing 100084, China
2. Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China; Beijing Key Lab of Precision/Ultra‐Precision Manufacturing Equipments and Control, Tsinghua University, Beijing 100084, China; and The State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China