Because it was carrying a large number of batteries, it was also supposed to be able to spend an significant amount of time running on battery power in “silent watch mode”, where it would be hard to detect, because it would be operating without running its engine while its sensors took in information about its immediate vicinity and relayed it across the network.
It turned out that a “significant amount of time” ended up to be something less than an hour because of the power consumption of the sensors, computers, and communications systems.
It turns out something very similar is happening with self-driving cars:
For longtime residents of Pittsburgh, seeing self-driving cars built by Uber, Argo AI, and others roam their streets is nothing new. The city’s history with robot cars goes back to the late 1980s, when students at Carnegie Mellon University caught the occasional glimpse of a strange vehicle lumbering across campus. The bright-blue Chevy panel van, chugging along at slower than a walking pace, may not have looked like much. But NavLab 1 was slowly—very slowly—pioneering the age of autonomous driving.
Why did the researchers at CMU’s Robotics Institute use the van instead of, say, a Prius? First, this was a decade before Toyota started making the hybrid. Second, the NavLab (that’s Navigational Laboratory) was one of the first autonomous vehicles to carry its computers with it. They needed space, and lots of it. For the four researchers monitoring computer workstations, with their bulky cathode ray monitors stretched across a workbench. For the on-board supercomputer, camera, giant laser scanner, and air-conditioner. And for the four-cylinder gasoline engine that did nothing but generate electricity to keep the kit running.
Thirty years on, the companies carrying that early research into reality have proven that cars can indeed drive themselves, and now they’re swiveling to sort out the practical bits. Those include regulations, liability, security, business models, and turning prototypes into production vehicles, by miniaturizing the electronics and reducing that massive electricity draw.
Today’s self-drivers don’t need extra engines, but they still use terrific amounts of power to run their onboard sensors and do all the calculations needed to analyze the world and make driving decisions. And it’s becoming a problem.
A production car you can buy today, with just cameras and radar, generates something like 6 gigabytes of data every 30 seconds. It’s even more for a self-driver, with additional sensors like lidar. All the data needs to be combined, sorted, and turned into a robot-friendly picture of the world, with instructions on how to move through it. That takes huge computing power, which means huge electricity demands. Prototypes use around 2,500 watts, enough to light 40 incandescent light bulbs.
“To put such a system into a combustion-engined car doesn’t make any sense, because the fuel consumption will go up tremendously,” says Wilko Stark, Mercedes-Benz’s vice president of strategy. Switch over to electric cars, and that draw translates to reduced range, because power from the battery goes to the computers instead of the motors.
Don’t be depressed. Self driving cars are only 10 years away, and will be just 10 years away for the next few decades, just like fusion and the Iranian nuclear arsenal.