Vehicles that move across the ground usually have either wheels, tracks, or legs. A walking vehicle has the advantage on uneven terrain. You can base a design concept on many living analogs, for nature has no use for the wheel.
Above is a scratch-built arthropod-based vehicle from Dinotopia: The World Beneath. The small maquette helped to visualize it in three dimensions and from various angles. The design is based on an extinct shrimplike invertebrate.
In the story, the vehicle, or “strutter” as it is called in Dinotopia, gets out of control and fights another strutter, while Arthur Denison and his friends watch in horror.
One reason wheels never arose in nature is the difficulty of designing a circulatory system that could work across a turning axle. Birds, humans, and a few mammals use two legs, but four, six or more legs are more common. Below is a full-size working model of a Japanese armored tech.
Engineers who design the drive mechanisms for walking vehicles usually have to solve three problems: how to translate the energy of the motor to the back and forth movement of the leg, how to achieve balance, and how to steer and change direction.
Tomorrow: part two, including Arthur Denison's strutter.
Addendum: Blog reader Scibotic has suggested these awesome YouTube videos. Thanks, Ben:
Mondo Spider, homemade walking vehicle with driver: link
Walking Sculptures, passive wind-powered beach walker with many legs: link
Big Dog, a four-legged autonomous vehicle that recovers balance on ice and uneven terrain: link