Tumble Stability Criterion Using Gravito-Inertial Acceleration for Wall-Climbing Motion of Legged Robots

Abstract

To address the stability of wall climbing motions in legged robots, the Tumble Stability criterion offers several advantages in addition to its computational simplicity: 1) it can be applied in scenarios where the robot's centroid projection is not defined (e.g., wall climbing), and 2) it easily incorporates the ground gripping capability in the calculation of stability margin. In this study, the conventional Tumble Stability judgment theory is reorganized in the acceleration domain to derive a “GIA Stable Space,” representing a stable region for the robot's gravito-inertial acceleration (GIA) and visualized as a polyhedron. A quantitative metric, named GIA Margin, is defined as the geometric distance between the robot's GIA vector and the polyhedron's side. The GIA Margin serves as an extension of the conventional support polygon and centroid projection, providing a measure to evaluate the level of stability. As a representative application of this approach, stable motion planning based on GIA Margin for a wall-climbing legged robot is presented.