[1] Univ Paris 06, Inst Robot & Intelligent Syst, F-75252 Paris 05, France
[2] Univ Coimbra, Inst Syst & Robot, P-3000 Coimbra, Portugal
[3] Kings Coll London, Ctr Robot Res, London, England
[4] Univ Poitiers, Inst P, Poitiers, France
[5] Univ Hamburg, Tech Aspects Multimodal Syst Inst, Hamburg, Germany