Asymptotic stability of dynamic bipedal gait with constraint on impact posture

This paper studies the efficiency and asymptotic stability of a dynamic bipedal gait with a constraint on the impact posture. First, we generate a gait by using tracking control to achieve the desired trajectory of the hip-joint angle, and show that there is a trade-off between efficiency and robustness through a numerical simulation. Second, we investigate the asymptotic stability of the gait from the mechanical energy balance viewpoint, and discuss the importance of the control input properties. Furthermore, we point out that there is a feedback in mechanical energy in the discrete walking system, and it is difficult to detect a stable 2-period gait.