What type of vehicle did Leonardo da Vinci design with three wheels and a clockwork motor?

Leonardo da Vinci designed a self-propelled cart powered by a clockwork mechanism.

The cart was drawn as a three-wheeled vehicle, with two driving wheels and a smaller steering wheel. Springs supplied the stored energy, while gearing controlled the release of that energy. The design could move without a person or animal pushing it, making it an early concept for an autonomous vehicle.

Leonardo probably intended the cart for theatrical or ceremonial use. A reconstructed model based on his drawings was displayed at events connected with the celebrations for the 500th anniversary of his birth. Because the original machine was never built in Leonardo’s lifetime, modern reconstructions are interpretations of incomplete drawings.

The cart is sometimes called a robot because it could move automatically, but it was not an electronic robot. Its operation depended entirely on mechanical springs, gears, and a steering arrangement.