Perspective Chapter: Multi-Contact Humanoid Stability for Increased Interaction in Unstructured Environments

Abstract

This paper presents a practical solution to the problem of multi-legged robot stability moving on unstructured 3D terrains using a multi-contact approach. The solution is based on a modified version of the contact wrench set method, which has been reformulated to utilize three arbitrary contact points representing the physics of contact between the robot and the environment. The new formulations are then used to test the stability of a life-size humanoid robot. The proposed method extends available formulations making the CWS tool suitable for a variety of terrains having various physical and geometrical characteristics including heterogenous coplanar (e.g., stairs and sloped terrain) and noncoplanar surfaces (e.g., gravel, sand, compliant terrains, etc.). The results provided by the new formulations are visualized using a graphical visualization tool, showing the adaptability of the proposed formulation in multi-contact locomotion. The results show that the proposed approach effectively quantifies the robot’s stability on a wide range of surfaces and environments, such as mines, industrial facilities, and urban search and rescue operations. Experimental tests on a life-size humanoid are also presented.