3 ms·

> The radar and ultrasonics are used to detect vehicles I don't understand why the truck wasn't detected. Not exactly a small target.

Kliment 10y ago
Because the radar is at headlight level, and the truck had a lot of ground clearance.
- davidf18 10y ago
  Well that's clearly a design flaw and speaks to the lack of engineering on the part of Tesla which I find frightening. In a different domain, nuclear power plant design, the Three Mile Island plant had a solenoid activated valve for letting high pressure out of the reactor vessel. The problem was that although the plant operators said set the valve to close, the valve was stuck open. It turns out that the control panel light signifying that the valve was closed simply displayed the signal sent to the solenoid, not that the valve had actually closed. No secondary valve, no meter to determine flow. There had been a operator's manual change for TMI and other plants of the same design, but the proper hardware change was never made. Hence TMI. But I worry about the kind of thinking as in TMI and also in Tesla.
  - vvanders 10y ago
    FYI the dashboard on the Tesla shows exactly what the sensors are seeing, so in some respects it's a full feedback loop unlike the 3MI example above.
    - davidf18 10y ago
      Well, yes, they got that right, but I was speaking in terms of not thinking through the engineering in a mission critical design (and in the case of the TMI reactor it had to be approved by the Nuclear Regulatory Commission or whatever its predecessor was). TMI failed in this level of design thinking which would seem fairly obvious (as did NRC in plant design review) scares me in terms of overall engineering thinking. (In other words, if they got that wrong, what else did the designers get wrong). In the case of Tesla, they have to engineer so that the cars knows about obstacles before crashing into them. The fact that Tesla did not think through this pretty obvious scenario is frightening and suggests a fault in their overall process in engineering. I just feel that Tesla cannot be trusted in terms of engineering unless they have some very smart group check their design. I doubt BMW would have made such a mistake.
      - bllguo 10y ago
        Please, stop with the fearmongering. You are coming to some weird conclusions.
        davidf18 10y ago
        No, I am someone who has a BS EE/CS degree that worked four years as an engineer at a large firm. It is not fear mongering. It is legitimate questioning about engineering, from someone who has the experience. For all of his self-promotion and as head of a car company and a rocket company, Elon Musk has never worked as an engineer for a large firm where he'd be mentored in engineering. For example, the CEO of GM is an engineer (EE) who was mentored in engineering. https://en.wikipedia.org/wiki/Mary_Barra https://en.wikipedia.org/wiki/Mary_Barra And the same for IBM: (EE & CS) https://en.wikipedia.org/wiki/Ginni_Rometty https://en.wikipedia.org/wiki/Ginni_Rometty
        vvanders 10y ago
        > lack of engineering on the part of Tesla which I find frightening. That looks a tad like fear mongering.
        davidf18 10y ago
        > That looks a tad like fear mongering. Please be specific. What is the fear mongering? It is a statement from someone educated as an engineer and trained as an engineer. Engineering, whether it is designing buildings, cars, airplanes, is thinking through the scenarios and testing for them. This seems to be a situation where they were ruling out overhead signs, but because of trucks clearance of these signs would be well over 10 feet and they could check for anything under 10 feet or 8 feet and should have. And, as I said before, if they didn't think this through, what else that we can't see are they not thinking through?
        vvanders 10y ago
        Just because you're an engineer doesn't make all of your arguments automatically correct. I've got the word "Engineer" in my job title but I don't beat people over the head with it when I want to make an argument for a technical position. It's not like they haven't thought this through. Tesla has been clear that this is a Driver Assistance, not a full autonomous car. There are multiple warnings, including every time you enable auto pilot that makes it clear you must pay attention. This accident while tragic from current reports looks like the driver was not paying attention to the road. The best way that we're going to get to fully autonomous cars is to collecting real world data and I think auto pilot has been a reasonable approach in that direction.
  - danbruc 10y ago
    The problem is, as far as I know, if you point the radar upwards, you will start detecting structures above the street like traffic lights and signs.
    - davidf18 10y ago
      Well, that might very well be true, but that's what engineering is about, thinking how to make it work.
    - euyyn 10y ago
      Not sure why would that be a problem.
- Symmetry 10y ago
  Also, aviation radars are built to reject signals from objects that are stationary relative to the ground so they aren't swamped by signals from the ground itself ("ground clutter"). Does Tesla's radar do something similar? If so it'll have no trouble picking up other cars traveling along the road but won't be able to see a stationary truck.
- gambiting 10y ago
  Well, I have a collision warning system in my Mercedes, and recently I drove through a narrow road which had loads of grass just hanging onto the road - the collision warning system was going nuts, beeping constantly, and had I not been applying throttle myself it would have braked the car on its own. I definitely remember reading that Teslas generally disregard anything at roof level to avoid tree branches interfering with the autopilot in the similar way the grass was interfering with my Mercedes - I can only imagine Tesla engineers asking themselves "how often, exactly, are you going to have a stationary metal object at exactly roof height, on a highway? If it's at that height on a public road, it can't be a solid/permanent object" - turns out, it can be, as rare as it is.
  - happyslobro 10y ago
    Clearly, any kind of always-on automation that is responsible for braking, must be able to gauge the strength and importance of obstacles. For example, driving through that grass slowly and carefully, is ok. If there is a wire hanging across a road, then that is definitely something to stop for. I'm thinking that a very good visual AI would be necessary to make distinctions like this; radar won't even see a wire, I don't think, and to lidar, it would look a lot like the grass. A touch-sensitive coating on the car would probably be a good idea too, so that the car can tell when if it is starting to scratch its paint on what it thought was an insignificant obstacle, like a branch. Simply not looking at obstacles in one area because of the difficulty of rejecting false positives is a terrible idea, and demonstrates that that AI is not ready to drive.
- rrauenza 10y ago
  Musk responded with this regarding radar questions: "Radar tunes out what looks like an overhead road sign to avoid false braking events" https://twitter.com/elonmusk/status/748625979271045121 https://twitter.com/elonmusk/status/748625979271045121
  - davidf18 10y ago
    Overhead road signs have a huge highly clearance (think of those tall trucks). I don't understand why they didn't check for clearance of 10 feet.
    - Animats 10y ago
      Tesla's radar probably just looks outward in a horizontal plane. That's what the old Eaton VORAD and most of its successors did. There are newer automotive radars which scan both horizontally and vertically [1], but Tesla doesn't seem to have those. When I was developing Grand Challenge software, I used to have an Eaton VORAD looking out my window at home, tracking vehicles going through an intersection. It could see cars, but usually not bicycles. Range and range rate were good; azimuth info was flaky. Stationary objects didn't register because it was a Doppler radar. Output from the device was a list of targets and positions, encapsulated in Serial Line Interface Protocol. The big problem with these radars is not seeing the road itself as an obstacle. When you're moving, everything has a Doppler radar return. Usually, the road is hit at such an oblique angle that it doesn't reflect much. But there are exceptions. The worst case is a grating-floor bridge. LIDAR isn't a panacea. The charcoal-black upholstery used on many office chairs is so non-reflective in IR that a SICK LMS can't see it at point-blank range. [1] http://www.fujitsu-ten.com/business/technicaljournal/pdf/38-1.pdf http://www.fujitsu-ten.com/business/technicaljournal/pdf/38-...

Kliment 10y ago

Because the radar is at headlight level, and the truck had a lot of ground clearance.

davidf18 10y ago
Well that's clearly a design flaw and speaks to the lack of engineering on the part of Tesla which I find frightening. In a different domain, nuclear power plant design, the Three Mile Island plant had a solenoid activated valve for letting high pressure out of the reactor vessel. The problem was that although the plant operators said set the valve to close, the valve was stuck open. It turns out that the control panel light signifying that the valve was closed simply displayed the signal sent to the solenoid, not that the valve had actually closed. No secondary valve, no meter to determine flow. There had been a operator's manual change for TMI and other plants of the same design, but the proper hardware change was never made. Hence TMI. But I worry about the kind of thinking as in TMI and also in Tesla.
- vvanders 10y ago
  FYI the dashboard on the Tesla shows exactly what the sensors are seeing, so in some respects it's a full feedback loop unlike the 3MI example above.
  - davidf18 10y ago
    Well, yes, they got that right, but I was speaking in terms of not thinking through the engineering in a mission critical design (and in the case of the TMI reactor it had to be approved by the Nuclear Regulatory Commission or whatever its predecessor was). TMI failed in this level of design thinking which would seem fairly obvious (as did NRC in plant design review) scares me in terms of overall engineering thinking. (In other words, if they got that wrong, what else did the designers get wrong). In the case of Tesla, they have to engineer so that the cars knows about obstacles before crashing into them. The fact that Tesla did not think through this pretty obvious scenario is frightening and suggests a fault in their overall process in engineering. I just feel that Tesla cannot be trusted in terms of engineering unless they have some very smart group check their design. I doubt BMW would have made such a mistake.
    - bllguo 10y ago
      Please, stop with the fearmongering. You are coming to some weird conclusions.
      - davidf18 10y ago
        No, I am someone who has a BS EE/CS degree that worked four years as an engineer at a large firm. It is not fear mongering. It is legitimate questioning about engineering, from someone who has the experience. For all of his self-promotion and as head of a car company and a rocket company, Elon Musk has never worked as an engineer for a large firm where he'd be mentored in engineering. For example, the CEO of GM is an engineer (EE) who was mentored in engineering. https://en.wikipedia.org/wiki/Mary_Barra https://en.wikipedia.org/wiki/Mary_Barra And the same for IBM: (EE & CS) https://en.wikipedia.org/wiki/Ginni_Rometty https://en.wikipedia.org/wiki/Ginni_Rometty
        vvanders 10y ago
        > lack of engineering on the part of Tesla which I find frightening. That looks a tad like fear mongering.
        davidf18 10y ago
        > That looks a tad like fear mongering. Please be specific. What is the fear mongering? It is a statement from someone educated as an engineer and trained as an engineer. Engineering, whether it is designing buildings, cars, airplanes, is thinking through the scenarios and testing for them. This seems to be a situation where they were ruling out overhead signs, but because of trucks clearance of these signs would be well over 10 feet and they could check for anything under 10 feet or 8 feet and should have. And, as I said before, if they didn't think this through, what else that we can't see are they not thinking through?
        vvanders 10y ago
        Just because you're an engineer doesn't make all of your arguments automatically correct. I've got the word "Engineer" in my job title but I don't beat people over the head with it when I want to make an argument for a technical position. It's not like they haven't thought this through. Tesla has been clear that this is a Driver Assistance, not a full autonomous car. There are multiple warnings, including every time you enable auto pilot that makes it clear you must pay attention. This accident while tragic from current reports looks like the driver was not paying attention to the road. The best way that we're going to get to fully autonomous cars is to collecting real world data and I think auto pilot has been a reasonable approach in that direction.
- danbruc 10y ago
  The problem is, as far as I know, if you point the radar upwards, you will start detecting structures above the street like traffic lights and signs.
  - davidf18 10y ago
    Well, that might very well be true, but that's what engineering is about, thinking how to make it work.
  - euyyn 10y ago
    Not sure why would that be a problem.
Symmetry 10y ago
Also, aviation radars are built to reject signals from objects that are stationary relative to the ground so they aren't swamped by signals from the ground itself ("ground clutter"). Does Tesla's radar do something similar? If so it'll have no trouble picking up other cars traveling along the road but won't be able to see a stationary truck.
gambiting 10y ago
Well, I have a collision warning system in my Mercedes, and recently I drove through a narrow road which had loads of grass just hanging onto the road - the collision warning system was going nuts, beeping constantly, and had I not been applying throttle myself it would have braked the car on its own. I definitely remember reading that Teslas generally disregard anything at roof level to avoid tree branches interfering with the autopilot in the similar way the grass was interfering with my Mercedes - I can only imagine Tesla engineers asking themselves "how often, exactly, are you going to have a stationary metal object at exactly roof height, on a highway? If it's at that height on a public road, it can't be a solid/permanent object" - turns out, it can be, as rare as it is.
- happyslobro 10y ago
  Clearly, any kind of always-on automation that is responsible for braking, must be able to gauge the strength and importance of obstacles. For example, driving through that grass slowly and carefully, is ok. If there is a wire hanging across a road, then that is definitely something to stop for. I'm thinking that a very good visual AI would be necessary to make distinctions like this; radar won't even see a wire, I don't think, and to lidar, it would look a lot like the grass. A touch-sensitive coating on the car would probably be a good idea too, so that the car can tell when if it is starting to scratch its paint on what it thought was an insignificant obstacle, like a branch. Simply not looking at obstacles in one area because of the difficulty of rejecting false positives is a terrible idea, and demonstrates that that AI is not ready to drive.
rrauenza 10y ago
Musk responded with this regarding radar questions: "Radar tunes out what looks like an overhead road sign to avoid false braking events" https://twitter.com/elonmusk/status/748625979271045121 https://twitter.com/elonmusk/status/748625979271045121
- davidf18 10y ago
  Overhead road signs have a huge highly clearance (think of those tall trucks). I don't understand why they didn't check for clearance of 10 feet.
  - Animats 10y ago
    Tesla's radar probably just looks outward in a horizontal plane. That's what the old Eaton VORAD and most of its successors did. There are newer automotive radars which scan both horizontally and vertically [1], but Tesla doesn't seem to have those. When I was developing Grand Challenge software, I used to have an Eaton VORAD looking out my window at home, tracking vehicles going through an intersection. It could see cars, but usually not bicycles. Range and range rate were good; azimuth info was flaky. Stationary objects didn't register because it was a Doppler radar. Output from the device was a list of targets and positions, encapsulated in Serial Line Interface Protocol. The big problem with these radars is not seeing the road itself as an obstacle. When you're moving, everything has a Doppler radar return. Usually, the road is hit at such an oblique angle that it doesn't reflect much. But there are exceptions. The worst case is a grating-floor bridge. LIDAR isn't a panacea. The charcoal-black upholstery used on many office chairs is so non-reflective in IR that a SICK LMS can't see it at point-blank range. [1] http://www.fujitsu-ten.com/business/technicaljournal/pdf/38-1.pdf http://www.fujitsu-ten.com/business/technicaljournal/pdf/38-...