1. Department of Robotics Engineering; Department of Information and Communication Engineering; Brain Engineering Convergence Center; Daegu Gyeongbuk Institute of Science and Technology; Daegu 49288 Republic of Korea
2. Department of Engineering Mechanics; Soft Matter Research Center, and Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province; Zhejiang University; Hangzhou 310027 China
3. School of Electrical Engineering and Computer Science; Gwangju Institute of Science and Technology; 123 Cheomdan-gwagiro Buk-gu Gwangju 61005 Republic of Korea
4. School of Electrical Engineering; Korea Advanced Institute of Science and Technology; Daejeon 34141 Republic of Korea