1. Department of Robotics Engineering, DGIST, 50-1 Sang-ri, Hyeongpung-myeon, Dalseong-gun, Daegu 42988, South Korea
2. DGIST-ETH Microrobot Research Center, DGIST, 50-1 Sang-ri, Hyeonpung-myeon, Dalseong-gun, Daegu 42988, South Korea
3. Funtional Ceramics Group, Korea Institute of Material Science, 797 Changwondaero, Seongsangu, Changwon 51508, South Korea
4. Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA