Dynamic simulation of biped walking on loose soil

Most of the studies on biped walking on even or uneven terrain have assumed stiff ground. This paper proposes a dynamic contact model between foot and loose soil. The proposed contact model provides sinkage of the foot, slip of the sole and reactive force acting on the foot on loose soil. Sinkage of the foot and slip of the sole are calculated utilizing terramechanics model, which are important characteristics for biped robot to walk on loose soil. Reactive force acting on the foot on loose soil is calculated using spring-damper model between the foot and the deformed ground. By applying the proposed contact model to a usual dynamics simulator, dynamic sinkage and slip phenomenon during biped walking on loose soil are simulated. Additionally, in order to verify the simulation result, experiments were carried out using a humanoid robot.