Power consumption for full level 5 self driving robo taxis[Discussion] : SelfDrivingCars

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I originally posted this over on the /Energy sub but since I just realized there was an established sub for JohnnyCabs figured I would paste over here:

For those of you that might not be familiar with the demands for systems being testing for use as taxis, here’s some info via 3rd parties. First, it’s important to understand the difference between a 4 system, which can drive itself some of the time under ideal conditions, and self which is a vehicle that can drive itself with zero input from a human user under every scenario and all weather conditions.

There’s a huge leap in computing power plus sensor suite to move from level 4 to a full level 5 and of course, as of today, a full level 5 does not actually exist yet. Let’s take a quick peek at the previous power figures and the downward trend.

Cruise’s early prototypes were consuming somewhere between 3-4 kW continuously. The newer systems are much less but no official numbers are released. Here’s the quote:

Cruise CEO Vogt declined to discuss most specifics about the computer platform being used in the Bolt EV, including what chips are being used. He did, however, acknowledge there are two primary identical computers running in parallel, along with a third with a different architecture that functions as a backup.
All of this hardware requires electrical power—and lots of it. Two independent power supplies ensure that all aspects of the car get their flow of electrons at all times. Farah acknowledged that the first-generation prototypes used about 3 to 4 kW of electrical power for the automated driving system and that the newer cars use less, but he declined to say how much more efficient they were.

Keep in mind that Cruise has not actually solved full level 5 yet so the exact amount of computing required will remain unknown for a little longer.

Next, let’s look at the power of some of the other development projects. This is based on a Nvidia test vehicle:

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.

That’s for testing only and Nvidia is projecting that the powering the processors themselves will eventually drop down to 500W:

Nvidia believes that a fully self-sufficient, no-steering-wheel-or-pedals kind of driverless car will need to run on a platform it’s calling Pegasus. With two Xavier chips and two more GPUs, this platform can crunch 320 trillion operations per second and keep power consumption to an acceptable 500 watts.

Again, the development systems have not solved full level 5 either. So, let’s look at real world data from systems that are on the road or have been real world testing for years: Starting with a level 2-3 advanced driver assistance consumes roughly 220W-240W continuously with a level 4ish (closer to Google/Waymo but still requires a driver) consuming a little more at roughly 325W continuously.

The 500W computing target projected by Nvidia is considered “close enough” to get the ball rolling. At the same time, this does not factor in the necessary redundancies that every single full level 5 will be required to have to carry passengers. The low side projections are 500W and the high side is over 1+kW so we;ll go with the middle ground of all in average power consumption of 750W including double/triple redundancy for safety critical.

Urban settings will be the first markets for robo taxis so a smallish BEV should be able to get 4 miles/kWh with decent weather conditions. Using our 750W estimation, each hour the self driving system is operation reduces the driving range by 3 miles. Yes, you can quick charge in between fares, but this also requires a larger energy capacity battery, most likely 50kWh or larger to handle peak charging rates over 100+kW. A 15-25 kWh battery pack will not survive very long under these conditions.

Here are the links to the quotes and figures:

https://www.caranddriver.com/news/gm-and-cruise-finally-give-a-peek-behind-the-curtain-of-their-automated-driving-program

https://www.wired.com/story/self-driving-cars-power-consumption-nvidia-chip/

https://pubs.acs.org/doi/10.1021/acs.est.7b04576

If you have first hand experience with robo taxis in the real world, how difficult will it be to get the energy consumption under 1kW for mass deployment?



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