What Leonardo da Vinci machine was designed to move by itself using a wound spring?

Leonardo da Vinci designed a self-propelled cart powered by a wound spring.

The cart appears in drawings from the late fifteenth century and is often described as an ancestor of the automobile. Its movement came from coiled springs housed inside the machine, rather than from an animal, person, or engine. A system of gears transferred spring energy to the wheels, while programmable components helped determine the route.

The design may have been intended for theatrical performances or court spectacles. Leonardo’s notes and sketches show how he combined mechanical timing, stored energy, and steering. Unlike a modern car, the cart had no combustion engine, brakes, suspension system, or reliable steering mechanism in the modern sense.

Reconstructions have shown that the design can move when interpreted and built carefully, although surviving drawings leave technical details open to debate. It is commonly called a “robot” in popular accounts, but “self-propelled cart” is the more precise description of the vehicle itself.