1. Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University , Seoul 08826 , Republic of Korea
2. Department of Computer Science, George Mason University , Fairfax, VA 22030 , USA
3. Soft Robotics Research Center, Seoul National University , Seoul 08826 , Republic of Korea
4. Department of Mechanical and Aerospace Engineering, Institute of Advanced Machines and Design, Seoul National University , Seoul , Republic of Korea