The first aircraft autopilot system was developed by Sperry in 1912, and in many ways wasn’t that different from the secret of Whitehead’s torpedo. The original autopilot, known as a “gyroscopic stabilizer apparatus,”7 was composed of a pair of gyroscopes, one connected to the heading indicator and one to the attitude indicator and controlling, via hydraulics, the airplane’s elevators and rudder. This early autopilot allowed a plane to fly level on a particular compass heading, freeing the pilot from many tedious hours of constant attention.
The first really significant use of an autopilot system came in 1931 when Wiley Post set a record for flying his Lockheed Vega airplane around the world in less than eight days. Post’s Vega had a more developed (than that original 1931 system, at least) Sperry Autopilot installed, which Post nicknamed “Mechanical Mike.”
For what it did, Mechanical Mike was surprisingly small, being only about 9 inches by 10 inches by 15 inches.8 The box housed two air-driven, 15,000 rpm (revolutions per minute) gyroscopes, one for azimuth/direction and one for lateral control of the airplane. Air-actuated servo valves connected to the gyroscopes hydraulically controlled the aileron, elevator, and rudder of the plane, giving full three-axis control of the aircraft.
Mechanical Mike required no electrical power, being entirely pneumatic, and only weighed seventy pounds. These were significant advantages over other autopilot systems, and Mike proved to be remarkably reliable. Mechanical Mike and other early gyro-based autopilot systems are significant in the development of autonomous vehicles because they represent the very first time a fully mechanical vehicular control system was trusted enough to transport passengers. The wide use of the Mechanical Mike following Post’s trip marked the first mass deployment of a situationally/environmentally reactive autonomous vehicle system, and, with nearly every major aircraft today employing a much more advanced version, represents the most common autonomous vehicle fleet currently in use on Earth.
World War II: Project Pigeon
The desire to have an autonomous system that could not just react to basic input about the environment—like speed and heading—but could actually sense, track, follow, or aim at a particular target, has been around since long before we had the means to produce machines capable of such tasks. That’s why things like Project Pigeon came into existence; sometimes, we didn’t want to wait around until we developed such machines, and instead borrowed the equipment we needed from nature. Even if that equipment was pigeons.
An autonomous vehicle that can track an object and make turns or otherwise modify its course to track an object is, naturally, highly useful in warfare, where so much is concerned with sending moving things along very fast to chase down and slam into other moving things. To pull this off, you need some sort of visual tracking and processing system, which pigeons already have.
The famous behaviorist B. F. Skinner realized this, and during World War II employed specially trained pigeons to steer a missile at his intended target. Skinner developed a nose cone for a missile that contained three windows, each one with a pigeon looking out of it. These pigeons had been trained via operant conditioning9 (basically, rewarded when a desired behavior was performed and punished when not) to peck at a target seen through the window. By pecking on the window that contained the target, the pigeon actuated controls that allowed the missile to adjust its course and keep the target centered.
The system was said to have performed well in simulations but Skinner complained that no one would take him seriously.10 There’s a lot of reluctance for people to entrust weapons of war to pigeons, a prejudice that still holds even to this day.
1940: Automatic Transmission
While not strictly a self-driving innovation, the development of the automatic transmission should be considered a step on the way to autonomy for automobiles. It was even referred to as “self-drive” in many early contemporary descriptions, because to people used to the near-constant shifting of gears, it felt like the car itself was doing a lot more work.
And the truth is it was. Determining the proper gear ratio for the needs of the car wasn’t trivial, and the automatic transmission freed the driver to focus on the more fundamental tasks of driving, speed modulation, and directional control.
First developed by General Motors (GM) (specifically its Cadillac and Oldsmobile divisions), the first commercially available automatic transmission was GM’s Hydra-Matic. Developed in 1939, the Hydra-Matic was the result of a number of earlier research efforts to make a self-shifting transmission, and used a combination of a planetary gearbox—a transmission type that uses a central sun gear and orbiting planet gears (you see why it’s called that, right?)—and a novel fluid coupling to achieve its goal. While heavy and complex, it was a success, and, for the American market in particular, regarding automatic transmissions, the industry never looked back.
1945: Cruise Control
Incredibly, automotive cruise control was invented by someone who didn’t even drive. In fact, it was invented by a blind man, Ralph Teetor, who came up with the idea after being annoyed at how bad his lawyer drove.11 Teetor was riding with his lawyer and having a conversation with him, and felt the car slowing whenever the lawyer was speaking, and accelerating when he was listening.
Nauseous but determined, Teetor wanted to find a way to keep a car’s throttle constant and free from the human driver’s fluctuation, and so developed cruise control, the first real semiautonomous assist device for cars.
Engine speed governors designed to keep an engine running at a constant speed have existed for over a century—you know those two spinning balls you sometimes see on old steam engines? That was a centrifugal governor, and also the origin of the phrase “balls to the wall,” since at maximum speed, those balls would be flung out nearly horizontally, or, you know, to the wall.
Balls or not, just keeping the engine at a constant speed really isn’t enough for a car cruise control system. Teetor computed the car’s actual speed based on how fast the driveshaft was rotating, and then used a bidirectional electric motor connected to the carburetor’s throttle to adjust the position of the throttle to keep the desired speed constant.12
Chrysler was the first to market the system, which was variously known as Speedostat or Auto-Pilot (foreshadowing Tesla’s name for their semiautonomous driving system), and later Chrysler came up with the name “Cruise Control,” which eventually stuck.
The cruise control innovation is important because this was the first taste most drivers had of any sort of actual driving automation. Sure, automatic transmissions—and before that, automatic spark advance and oiling and so on—took over many of the functions of the operation of a car that used to be manual, but those, including gear shifting, were less about the actual piloting of the vehicle itself and more about the technical requirements needed to get the car to drive at all.
Cruise control, though, was clearly different, in that it took one of the primary tasks of driving—speed control—away from the human driver and placed it under control of the machine. Sure, this was the simplest form of control, with no ability to independently sense its environment, but it was a start. Modern dynamic-cruise systems use radar to keep a set distance away from the car in front, and can brake automatically if the system determines it’s approaching
