What self-propelled machine did Leonardo da Vinci design to move without a person or animal pulling it?

Leonardo da Vinci designed a self-propelled cart that could move without a person or animal pulling it.

The machine is usually reconstructed as a three-wheeled cart powered by coiled springs. When the springs were wound, their stored energy turned the wheels through a system of gears. Steering could be set in advance with a mechanism that controlled the cart’s path.

Leonardo’s drawings do not provide every detail needed to prove exactly how the original mechanism would have behaved. Nevertheless, modern reconstructions have shown that the concept can work. In 2006, the Institute and Museum of the History of Science in Florence displayed a reconstruction based on Leonardo’s design.

The cart is sometimes called Leonardo’s “robot,” but it was not a humanoid robot. That nickname reflects its autonomous movement: once wound and configured, the machine could travel on its own. It is more accurately described as a self-propelled cart or programmable automaton.