Dynamic trajectory control of passing over stairs by a biped type leg-wheeled robot with nominal reference of static gait

We are studying a wheeled robot with the ability of going up and down stairs. We previously developed a wheeled robot called a `variable structure type four-wheeled robot' capable of passing over a single step, but it cannot negotiate the stairs whose tread is short compared with the wheelbase of the robot. In this paper, we propose a `biped type leg-wheeled robot' which has ability to pass over stairs with short treads. We also propose a trajectory planning method which uses a nominal static walking trajectory as a reference for the dynamic control of the robot, and investigate a trajectory control method using computer simulation. We finally confirm the effectiveness of our proposed method with a successful experiment of going up stairs by this robot.