What Leonardo da Vinci invention was a self-propelled cart driven by springs and considered an early robot?

Leonardo da Vinci's self-propelled cart was a spring-powered vehicle designed to move without being pushed or pulled by an animal.

The cart used coiled springs as its power source, with gears controlling the rotation of its wheels. A steering mechanism could set a predetermined route, making the machine an early example of programmable or autonomous mechanical motion. It was probably intended for theatrical or ceremonial use rather than transportation.

The design is preserved in Leonardo's drawings, but no original cart survives. In 2006, researchers and museum specialists built a working reconstruction based on the surviving plans. The replica demonstrated that the basic mechanism could operate, although details of the original design remain open to interpretation.

The cart is sometimes called Leonardo's robot, but that label can cause confusion. It was not a humanoid machine and did not make decisions independently. The term refers to its automated movement and its importance in the history of robotics and mechanical engineering.