A control architecture for dynamically stable gaits of small size humanoid robots

From the 1970's biped robots have had a large attention from the robotic research community. Yet the issue of controlling dynamically stable walking for arbitrary biped robots is still open. We propose a simple control architecture based on the use of the FRI (Foot Rotation Indicator) point and the support polygon. The major advantage of the proposed architecture is that motion planning (and eventually sensor based re-planning (slower feedback loop)) is limited to the leg joints whereas the trunk and arm degrees of freedom are controlled in closed loop (faster feedback loop) to achieve overall dynamic stability. Such architecture allows to decouple the problem of dynamic stable walking in the two relatively simpler problems of gait generation and robot stabilization. This architecture is particularly suited for small size robots having limited onboard computational power and limited sensor suits. The effectiveness of the proposed method has been validated through Matlab® simulations and experimental tests performed on a Robovie-MS platform.