What Leonardo da Vinci invention used a spring-powered mechanism to move without being pushed?

Leonardo da Vinci’s spring-powered vehicle was a self-propelled cart.

Leonardo designed the cart around 1478–1480, making it one of the earliest known concepts for a programmable, self-moving vehicle. Coiled springs supplied the energy, while a system of gears and cams controlled the wheels and the cart’s path. The front wheel arrangement could be set to produce a predetermined turn.

The device was probably intended for theatrical use rather than transport or military service. It may have been designed to appear during court celebrations, where a moving machine could create a dramatic effect without a visible person pushing it. Leonardo left drawings rather than a complete surviving machine.

In 2006, engineers at the Museo Nazionale della Scienza e della Tecnologia in Milan built a working replica based on Leonardo’s sketches. The cart is sometimes called a robot, but it had no sensing, decision-making, or electronic control. Its programmed mechanical motion is the key feature.