Which Leonardo da Vinci machine was designed to move using stored spring power?

Leonardo da Vinci’s machine designed to move using stored spring power was the self-propelled cart.

The cart appears in drawings from the late 15th century and is often described as an ancestor of the automobile or robotic vehicle. Large coiled springs stored energy, while a system of gears controlled the wheels and determined how far the cart would travel. A steering mechanism could also set a programmed path.

Leonardo may have intended the device for theatrical performances, ceremonial processions, or court entertainment rather than transportation. It did not contain an engine, and the surviving drawings do not provide every detail needed for a single certain reconstruction.

Modern replicas have demonstrated that the basic mechanism can work. The cart is sometimes incorrectly described as the first car, but that label projects modern road-vehicle technology onto a Renaissance clockwork machine.