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It's mostly due to limited sensors and immature algorithms. If you think about a sharp left turn with a wall on the right side of the road, there is a "station
by mdorazio 9y ago
It's mostly due to limited sensors and immature algorithms.
If you think about a sharp left turn with a wall on the right side of the road, there is a "stationary object" (the wall) in front of the vehicle throughout the turn that will be detected by radar and cameras. In order to navigate a situation like this, an autonomous vehicle has to have additional decision-making in place to effectively override "stationary object in front of me = stop" logic. But once you do that, it gets tricky to determine when you should ignore the "stationary object" and when you shouldn't.
On top of this, Tesla opted not to include LIDAR as a sensor in its vehicles, so it does not get a 3D point cloud to help identify what an object is and what to do with it. Instead, there's a high reliance on the cameras and radar, but these have some limitations. For example, it's difficult for a camera to distinguish between two objects of similar brightness and color, so for example if there's a white semi-trailer in front of a white wall 100ft away, the camera might not "see" the trailer. This can create situations where sensors are reporting conflicting data, which is bad - for example in the trailer situation, the camera would be saying "there's nothing in front of me until a wall 100ft away", but the radar would be saying "no there's something right in front of me". Or the radar might not "see" an obstacle that is a few feet off the ground while the camera is saying "there's something in front of me". Resolving these conflicts is hard.
- mirimir 9y agoI can see how cameras are basically useless. And also radar, because it just reports relative velocities. And without angular resolution, how could the system distinguish stationary objects on the sides from those straight ahead? Maybe there could be multiple highly directional radar "guns", operating at different frequencies.
- Dylan16807 9y ago> But once you do that, it gets tricky to determine when you should ignore the "stationary object" and when you shouldn't. That's not tricky. You never ignore it. A stationary object means that you will have to either stop or turn. You don't know which one yet, but you definitely know you'll have to take an action. If you haven't decided by some close point, you just pick one.
- mirimir 9y agoAs I understand it, what's hard is determining whether that stationary object is directly in front, or off to the side. Cars are always passing stationary objects on the sides.
- Dylan16807 9y agoThat doesn't really change my answer. If an object is almost directly in front of you, you either fine-tune your turning to avoid it, or you stop. There's no reason to ever ignore it.
- mirimir 9y agoAs I understand it, Tesla autopilot can't distinguish objects on the sides (such as road signs) from objects directly in front. And it must ignore road signs etc. So it ends up ignoring all stationary objects.
- Vik1ng 9y agoYou can't just slam the brakes on the highway. Just a question of time until you get rear ended.
- Piskvorrr 9y agoThere are other ways to stop than "apply full braking power until speed == 0".
- Piskvorrr 9y agoI would have thunk that to be a solved problem. Apparently not. https://jonathanwhiting.com/tutorial/collision/ https://jonathanwhiting.com/tutorial/collision/
- mirimir 9y agoAnd what's worse with systems like Tesla's autopilot, you don't have very much 2D resolution.