Robust Multi-Legged Walking Robots for Interactions with Different Terrains

Abstract

This paper explores the kinematic synthesis, design and pilot experimental testing of a six-legged walking robotic platform able to traverse through different terrains. We aim to develop a structured approach to designing the limb morphology using a relaxed kinematic task with incorporated conditions on foot-environments contact force direction (related to stability) and curvature constraints (related to maintaining contact). The design approach builds up incrementally starting with studying the basic human leg walking trajectory and then defining a “relaxed” kinematic task. The “relaxed” kinematic task consists only of two contact locations (toe-off and heel-strike) with higher order motion task specifications compatible with foot-terrain(s) contact and curvature constraints in the vicinity of the two contacts. As the next step, an eight-bar leg image is created based on the “relaxed” kinematic task and incorporated within a six-legged walking robot. Pilot experimental tests explore if the proposed approach results in an adaptable behavior which allows the platform to incorporate different walking foot trajectories and gait styles coupled to each environment. The results suggest that the proposed “relaxed” higher order motion task combined with the leg morphological properties and feet material allowed the platform to walk stably on the different terrains. The main advantage of the proposed method is that the platform has carefully designed limb morphology with incorporated conditions on foot-environment interaction and incorporates a single actuator to drive all six legs.