What machine did Leonardo da Vinci design to move itself using a spring-powered mechanism?

Leonardo da Vinci designed a self-propelled cart powered by coiled springs and intended to move without a person pushing it.

Leonardo sketched the cart in the late 15th century, probably around 1478–1480. Two large springs stored energy, while a system of gears transferred that energy to the wheels. A steering mechanism could be set in advance, allowing the cart to follow a predetermined route rather than being continuously guided.

The machine is sometimes called the first robot or an ancestor of the automobile, but both labels need care. It was not an autonomous computer-controlled vehicle, and it carried no engine in the modern sense. Its programmed steering and mechanical movement nevertheless make it an important example of Renaissance automation.

A full-scale reconstruction was built in 2006 by researchers associated with the Institute and Museum of the History of Science in Florence. The reconstruction showed that the design could work, although the surviving drawings leave some details open to interpretation.