Why is FSD proving to be so complicated in dynamic environments I.e. rain, low light, lack of road markings etc. is it an algorithm/computation limitation, is it sensory hardware, is it both? Or is it accomplishable, but not profitable?
In: 4
reliablility
I break it down in two points: 1 system, and 2 sensors.
1 system: any system can fail. Example of fail safe for planes: When it comes to a computer making a determination, the most used system in aviation is 2 dual autopilots, each controlling only half of the control inputs. where half AP1 does half the flight control movement, half AP1 checks AP2 solutions. AP2 is also, half doing half control movement and half checking AP1. As soon as one of the four does disagree, the AP that is different from the other 3 is disconnected. Result is you are left with only half of the flight control authority, so half as reactive.
The other more expensive one is to have 3 autopilots. For example one AP is flying the plane fully and 2 are backup. As soon as one disagree with the other 2, it is disconnected. If then the 2 remaining do disagree, they both disconnect.
Problem is that to guarantee a single autopilot function you have to install 2 enhanced identical systems, or three “simple” ones.
Having just 2 normal systems would not work as as soon as they disagree, none of them has a third reference to tell which of the two is the most correct.
A single one, will simply drive you into a mountain with no warning because it “thinks to be right but is not”. Which is the whole problem with recent car accidents. The AP does not know it is wrong, if it can’t recognize that, it can’t hand you the controls in time.
In all cases, a human pilot/driver, is needed to be attentive and ready to take control. You can’t watch a movie and trust the computer. It’s not a videogame.
2 Speaking about video games, here’s another really big issue. When you run Flight Simulator, the computer game knows where your plane is in the simulation, cause it’s the game itself determining it. So there’s not a big deal of calculation to autopilot the plane. You know where it is, where it should go, and just need simple math to change the control inputs to change course.
But in a real plane, the autopilot has no idea about where the plane is. You need sensors to tell things to it. You need altitude, airspeed, accelerometers, gyroscopes, maps, gps, radio navigation. All of these are thrown into a very complex equation, in the flight management computer, that then feeds your most likely position to the autopilot. Then the autopilot will control the plane using the same sensors.
When it comes to cars, you have way more obstacles than a plane. And you don’t have many choices about sensors. You can’t use radar, forget about cost, it’s just gonna fry the testicles of any pedestrian in front of you. You can use low power radar but then your detection range is similar to your parking sensor, awful. Rule out gps as it is intermittent in nature, and the accuracy is good for navigation but that’s a 1 meter accuracy. Imagine you drive on a highway, gps says you are one meter too much to the left, steers the car into the truck in the lane next to you. Radio navigation is good as long as you go 100+ mph in the sky. That’s not car use.
Sure you can measure wheels speed and angle of steering. You can use a LIDAR, a light based system similar to radar or sonar principles, or use cameras or both. Now, LIDAR shoots a laser, and measure what comes back. I course that’s cool but of course you don’t want to blind pedestrians. So LiDAR is usable only with very low energy and low energy means lower accuracy and range. Cameras have issues too, as they lose accuracy in the dark. Then both systems are light based, light can be disturbed by droplets on the lenses, rain, fog, mirrors. Light receivers can be temporarily blinded by other strong lights. Relying only to light based sensors means all your detection and guidance can completely fail for a single cause. In aviation they use different type of sensor to differentiate the threats, giving a system that has more elements that can disturb it, but can’t completely fail unless simultaneously disturbed on all the following elements: radio, light, magnetic, satellite, air and radar. On car it’s very hard to back up light sensor with non light sensors.
So, you need let’s say, a complex computer to interpreter the sensors data, you need multiple sensors to back up eachother, to prevent a single sensor error to kill you. Then you need to feed this data to multiple AP that are cross checking eachother. Then you need a backup human to take control as soon as the multiple AP do disagree and disconnect. Remember, disconnect means the multiple AP telling you “we are no more sure of our determinations, you better take control”. The other option is letting the AP going wherever it thinks is good to go and probably crash.
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