  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.
