Landing Control of Foot with Springs for Walking Robots on Rough Terrain

Landing control is one of the important issues for biped walking robot, because robots are expected towalk on not only known flat surfaces but also unknown and uneven terrain for working at various fields. Thispaper presents a new controller design for a robotic foot to land on unknown terrain. The robotic foot consideredin this study equips springs to reduce the impact force at the foot landing. There are two objectives in the landingcontrol; achieving the desired ground reaction force and positioning the foot on unknown terrain. To achieve thesetwo objectives simultaneously by adjusting the foot position, we propose a PI force controller with a desired footposition, which guarantees the robust stability of control system with respect to terrain variance, and exactpositioning of the foot to unknown terrain. Simulation results using the Open Dynamics Engine demonstrate theeffectiveness of the proposed controller