Ultrahigh-speed Strict Stealth Walking Based on Simultaneous Control of Horizontal and Vertical Ground Reaction Forces

Abstract

In this paper, we propose a method for achieving ultrahigh-speed strict stealth walking (USSW) by simultaneously controlling horizontal and vertical ground reaction forces. We consider a symmetrical eight-legged rimless wheel with an upper body with a telescopic joint and a flywheel. First, we design a control input to make the stance leg follow a fifth-order function of time whereas the upper body follow a sinusoidal trajectory, and maintain the vertical position of the center of mass (COM) at a constant value. We then propose an algorithm to identify the target initial angular velocity of the upper body where the time integral of the absolute value of the horizontal ground reaction force is minimized. Second, we design a control input that also maintains the moving speed of the COM in the horizontal direction at a constant, and propose an algorithm to numerically calculate the initial angular velocity of the upper body by referring to the initial angular velocity obtained. We investigate the properties of the USSW gait through numerical simulations.