Given that the vehicles are wheeled, they are limited in the severity of the terrain they can handle.
Legged vehicles are more terrain capable, but more difficult to control.
An Embodiment Existing legged vehicles are either autonomous for certain well-defined modes or manually controlled via individual actuation of the legs. Consider the analogy of a person riding a horse. The person provides high-level navigation commands by pulling on the reigns, leaning, etc. The horse selects a gait to match the desired speed and watches the terrain to avoid tripping and other hazards. The rider and horse form a coupled dynamic system, and together they can negotiate terrain inaccessible to wheeled vehicles.