Gait transitions and disturbance response for planar bipeds with reaction wheel actuation

Abstract

The reaction wheel stabilizer (RWS) concept for bipedal stabilization consists of a wheel that can be accelerated in order to impart a reaction torque on the rest of the biped. The beneficial effects of such a device (or emulation of such a device through limb motion) on transient body motions are not well understood. This work quantifies this phenomenon by comparing optimal trajectories for robots with and without an RWS in terms of energy efficiency and dynamic feasibility when attempting to execute speed transitions and disturbance response motions. Robots with RWS systems are able to more efficiently execute abrupt speed transitions, showing up to a 60% improvement in efficiency for single step transitions. In responding to forward push disturbances, the RWS improves efficiency by between 20 and 60% over the range of tested disturbances. These savings are significantly larger than those shown previously for periodic walking.