Impedance-based Motion Control of Passive-type Robot Porter for Handling an Object. - Zhi Dong Wang; Kenta Fukaya; Yasuhisa Hirata; Kazuhiro Kosuge (ROBIO, 2006)

Control Passive Mobile Robots for Object Transportation - Braking Torque Analysis and Motion Control. - Zhi Dong Wang; Kenta Fukaya; Yasuhisa Hirata; Kazuhiro Kosuge (ICRA, 2007)

Transporting an Object by a Passive Mobile Robot with Servo Brakes in Cooperation with a Human. - Yasuhisa Hirata; Zhi Dong Wang; Kenta Fukaya; Kazuhiro Kosuge (Adv. Robotics, 2009)