Ultrahigh-speed Strict Stealth Walking of Combined Rimless Wheel with 2-DOF Wobbling Mass

Abstract

This paper proposes a method for achieving ultrahigh-speed strict stealth walking (USSW) of a planar combined rimless wheel (CRW) with 2-DOF wobbling mass. In the first half, a stable USSW gait generation for the CRW on a non-slip road surface is investigated. We develop a 7-DOF mathematical model, and designing a strict output following control so that the entire COM position moves in the walking direction at a constant speed and the next stance foot can land on the ground stealthily. The numerical simulation shows that the resultant force of the horizontal ground reaction forces becomes zero according to the method. In the latter half, we introduce another model that added a rod to synchronize the rotational motion of the fore and rear legs with the aim of achieving USSW on the road surface where the coefficient of friction is zero. It is numerically shown that a stable USSW gait can be generated according to the modified output following control, but there is a problem that the vertical ground reaction force becomes negative during motion when the walking speed is very high.