1. Department of Electrical EngineeringKyoto UniversityKyotodaigaku‐Katsura, Nishikyo‐kuKyoto615‐8510Japan
2. MAC GroupCNRS, LAAS7 avenue du Colonel RocheF‐31077ToulouseFrance
3. Université de Toulouse; UPS, INSA, INP, ISAE; LAASF‐31077ToulouseFrance