Foothold Evaluation Criterion for Dynamic Transition Feasibility for Quadruped Robots

TL;DR

This paper introduces a new foothold evaluation criterion that assesses transition feasibility for quadruped robots, enhancing their ability to traverse complex terrains by considering dynamic and kinematic factors.

Contribution

It proposes a novel criterion integrating dynamic feasibility with a receding-horizon approach, combined with a vision-based foothold adaptation strategy for improved terrain navigation.

Findings

Validated in simulation and real-world experiments with HyQ robot.

Improved foothold selection leads to better stability and terrain traversal.

Demonstrated effectiveness in complex scenarios.

Abstract

To traverse complex scenarios reliably a legged robot needs to move its base aided by the ground reaction forces, which can only be generated by the legs that are momentarily in contact with the ground. A proper selection of footholds is crucial for maintaining balance. In this paper, we propose a foothold evaluation criterion that considers the transition feasibility for both linear and angular dynamics to overcome complex scenarios. We devise convex and nonlinear formulations as a direct extension of the Continuous Convex Resolution of Centroidal Dynamic Trajectories (C-CROC) in a receding-horizon fashion to grant dynamic feasibility for future behaviours. The criterion is integrated with a Vision-based Foothold Adaptation (VFA) strategy that takes into account the robot kinematics, leg collisions and terrain morphology. We verify the validity of the selected footholds and the generated trajectories in simulation and experiments with the 90kg quadruped robot HyQ.