4 ms·
There is presumably still some possibility of them failing in an "always reports 0" way
by Retr0id 2y ago
There is presumably still some possibility of them failing in an "always reports 0" way
- lostlogin 2y ago…Like when dismembered and spread across a bench.
- Arch-TK 2y agoIt's not unthinkable that whatever transducer takes rotation and turns it into a signal which is processed by an MCU and translated into CAN messages could get stuck producing one signal and trigger such a scenario without the car's control system needing to be on a bench.
- 0_____0 2y agoThere are some parts of engineering in safety systems where you have a single thing that could go wrong that would have serious consequences, and the result of the FMEA is that "it has to not do that".
- zardo 2y agoI don't think you'll find a wheel speed sensor without a few "outputs incorrect speed" failure modes.
- 0_____0 2y agoDetectability is one dimension of an error, and "bad wheel speed" has decent detectability I reckon - either through redundancy, grey codes, index pulse checking, bound checking. Also the issue experienced in the post wasn't an issue with a sensor per se.
- throw88888 2y agoSure, it is possible theoretically. However, most relevant regulation (IEC61508, ISO26262, DO-178X) requires that systems controlling machines in automotive, rail or aerospace have a possibility of dangerous faults lower than 10^-9 (over the expected lifespan). Many critical control systems like this are formally verified and/or extremely well-tested and have redundancy in both software and hardware.