Which Leonardo da Vinci invention used gears and a spring-powered mechanism to move without a rider?

Leonardo da Vinci’s self-propelled cart was a spring-powered vehicle designed to move without a rider. Drawn around 1478–1480, it is often described as an early ancestor of the automobile or robot.

The cart used coiled springs to store energy, while a system of gears controlled its motion. A programmable steering mechanism could make it follow a predetermined path, allowing the vehicle to travel and turn automatically for a short distance.

The original drawing was incomplete, so modern reconstructions rely on engineering interpretations. In 2006, researchers at the Museo Nazionale della Scienza e della Tecnologia in Milan built a working model. The cart was probably intended for theatrical performances or court spectacles rather than transportation.