Accurate estimation of drawbar pull of wheeled mobile robots traversing sandy terrain using built-in force sensor array wheel. - Keiji Nagatani; Ayako Ikeda; Keisuke Sato; Kazuya Yoshida (IROS, 2009)

Development of a Visual Odometry System for a Wheeled Robot on Loose Soil using a Telecentric Camera. - Keiji Nagatani; Ayako Ikeda; Genya Ishigami; Kazuya Yoshida; Isaku Nagai (Adv. Robotics, 2010)