1. School of Mechanical & Aerospace Engineering, Nanyang Technological University, Jurong West, Singapore
2. Centre national de la recherche scientifique-National Institute of Advanced Industrial Science and Technology (CNRS-AIST) Joint Robotics Laboratory (JRL), UMI3218/RL, Tsukuba, Japan
3. CNRS-AIST Joint Robotics Laboratory (JRL), UMI3218/RL, Tsukuba, Japan