Decoupled Control of Bipedal Locomotion Based on HZD and H-LIP

The walking control of bipedal robots poses challenges due to inherent coupling among the robot’s degrees of freedom. This paper introduces an approach to address this challenge by using decoupled control in the sagittal and frontal planes. The proposed control method takes advantage of Hybrid Zero Dynamics and Hybrid-Linear Inverted Pendulum for sagittal and frontal plane dynamics, respectively. The hybrid controller is successfully validated on a bipedal robot RobBIE, whose torso inertia is relatively high and if not adequately controlled can easily violate the point mass assumption in many reduced-order model based walking controllers developed previously. With the help of full-model based Hybrid Zero Dynamics, the robot can achieve stable walking behaviors at different velocities and adapt to various terrains and even moderate disturbances.