Motion Generation and Analysis of High-speed Stealth Walking on Stairs⋆

Abstract This paper proposes a method for achieving high-speed stealth walking on the stairs. First, we introduce a model of an underactuated rimless wheel with an upper body, and develop a strict output-following controller for generating the stance-leg motion. Second, we derive an approximate analytical solution of the target initial state of the upper body by using the linearized model, and observe the typical stealth walking motion on descending stairs. The energy efficiency is also numerically analyzed in terms of specific resistance. Third, we investigate generation of a stealth walking gait for the nonlinear model using the target initial state obtained in the linearized model. The gap between the nonlinear and linearized models created during the single-limb support phase is bridged during the double-limb support phase by using a tracking control to the third-order function of the upper-body angle.