Ken'ichi Koyanagi Hirohisa Hirukawa Shizuko Hattori Mitsuharu Morisawa Shinichiro Nakaoka Kensuke Harada Shuuji Kajita A pattern generator of humanoid robots walking on a rough terrain using a handrail. 2617-2622 2008 IROS http://dx.doi.org/10.1109/IROS.2008.4650686 conf/iros/2008 db/conf/iros/iros2008.html#KoyanagiHHMNHK08