1. INSERM U846 & CNRS, Lyon, France 69675, France
2. LAAS-CNRS, Toulouse, France
3. CNRS-AIST JRL (Joint Robotics Laboratory), UMI 3218/CRT, National Institute of Advanced Industrial Science and Technology (AIST), Umezono 1-1-1, Tsukuba, Ibaraki, 305-8568, Japan