What is the usual name for Leonardo da Vinci’s spring-powered four-wheeled vehicle?

Leonardo da Vinci’s spring-powered four-wheeled vehicle is usually called the self-propelled cart.

Leonardo designed the cart around 1478–1480. Large coiled springs stored energy and drove the wheels through a system of gears. The steering mechanism was programmable through blocks placed on a small control drum, allowing the cart to follow a predetermined path rather than requiring a driver.

The machine is often described as an early automobile, but it had no engine and could travel only a limited distance. It was probably intended for theatrical or ceremonial use, perhaps to create a moving surprise during court festivities. The original drawing is incomplete, so modern reconstructions have had to infer some details from related sketches.

In 2006, researchers at the Institute and Museum of the History of Science in Florence built a working reconstruction based on Leonardo’s surviving designs. The cart is also sometimes associated with the early history of robotics because its programmed movement resembles a simple automaton.