Control of a planar underactuated biped on a complete walking cycle

We address the problem of stabilizing a planar biped robot on a complete walking cycle. Our approach is based on singling out the three fundamental phases of motion of a biped: single and double-support, separated (sequentially) by an impact "instantaneous" phase. We propose control laws to drive the robot for a finite time during each phase, while ensuring certain robustness vis-a-vis the impacts which are treated as external perturbations.