Experimental verification of antagonistic stiffness planning for a planar parallel mechanism with 2-DOF force redundancy

† Nano Convergence and Manufacturing Systems Research Division, Korea Institute of Machinery and Materials, Daejeon 305-343, South Korea ‡ Department of Mechanical Engineering, Korea Air Force Academy, PO Box, 335-1, Ssangsu-Ri, Namil-Myeon, Cheongwon-Gun, Chungbuk 363-849, South Korea § School of Mechanical and Aerospace Engineering, Seoul National University, San 15-1, Shillim-dong, Kwanak-gu, Seoul 151-742, South Korea ¶ School of Mechanical and Aerospace Engineering, Sungkyunkwan University, 300 Cheoncheon, Suwon 440-746, South Korea ‖ School of Mechanical Engineering, Kookmin University, 861-1 Jeongneung-Dong, Songbuk-Gu, Seoul 136-702, South Korea