[1] Hokkaido Univ, Grad Sch Engn, Div Human Mech Syst & Design, Sapporo 0608628, Japan
[2] Osaka Univ, Grad Sch Engn Sci, Div Bioengn, Osaka 5608531, Japan
[3] Southeast Univ, Sch Instrument Sci & Engn, State Key Lab Bioelect, Jiangsu Prov Key Lab Remote Measurement & Control, Nanjing 210096, Peoples R China
[4] Hokkaido Univ, Fac Engn, Div Mech & Aerosp Engn, Sapporo 0608628, Japan
[5] Imperial Coll London, Fac Engn, Dept Bioengn, London SW7 2AZ, England