Hyatt Nakadoi David Sobey Masaki Yamakita Toshiharu Mukai Liquid environment-adaptive IPMC fish-like robot using extremum seeking feedback. 3089-3094 2008 IROS http://dx.doi.org/10.1109/IROS.2008.4650857 conf/iros/2008 db/conf/iros/iros2008.html#NakadoiSYM08