Postural Balance of an Underactuated Biped Robot With a Reaction Wheel

Practical and effective biped robots are trending toward reality with increasing interest in the technology and recent major innovations in nonlinear control theory. The development of underactuated techniques transitioned biped robot walking to a more elegant human-like motion. When disturbances are encountered, maintaining postural balance becomes a proven challenge that limits the practicality of these machines. This paper offers a solution to this issue by showing that an underactuated five-link reaction wheel-equipped planar biped robot can be posturally balanced successfully and efficiently with feedback control laws derived from the system’s zero dynamics and through task space optimization. The zero dynamics controller is shown to exhibit better performance compared to the task space controller in terms of settling time and total system work.