Using the transferability approach, the robot first explores how it can moves (is using the wheels OK? how to walk?) then it can exploit its discovery to move.
In this video, the robot quickly discovers that its wheels are not working and it finds a gait that is adapted to the grid.
Koos, S. and Mouret, J-B. (2011). Online Discovery of Locomotion Modes for Wheel-Legged Hybrid Robots: a Transferability-based Approach.
Proceedings of CLAWAR, World Scientific Publishing Co., publisher. Pages 70-77.