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Old 31st May 2013, 14:18   #91
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Default Re: Airbags deployed after hitting a dog. Understanding why?

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Originally Posted by DerAlte View Post
* The car was at 100Kmph 50m before a curve. And the driver didn't notice it because the airbag deployed? What was he doing 100m before the curve? And he wasn't braking when the dog made an appearance in front of him?
* Do you realize on roads where one can / is allowed to do 100kmph, and wherever visibility is limited or it is dangerous to drive at such speeds, speed limits are imposed to prevent accidents?

How do you propose the 'severity' of a likely crash is measured, to deploy the airbag in <100ms, with an acceleration sensor similar to the ones in smartphones? Please don't propose a system which costs more than the rest of the car.
I asked you to make a simple consideration and you are accusing me of overspeeding?
Do you want to say that the air-bag controllers are so stupid that they cannot measure a severity of crash? In that case video games would be smarter.
The severity of the crash is simply measured in the number of G forces acting on the car. When the G forces exceed a certain level, the air-bags are deployed. What makes that logic costlier than the car?

Last edited by GTO : 2nd June 2013 at 13:31. Reason: Quoted post edited
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Old 31st May 2013, 15:07   #92
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Default Re: Airbags deployed after hitting a dog. Understanding why?

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Originally Posted by Tejas Ingle View Post
I asked you to make a simple consideration and you are accusing me of overspeeding? ...
Huh? What? Where? When? (My English is usually very plain and simple!)

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Originally Posted by Tejas Ingle View Post
... Do you want to say that the air-bag controllers are so stupid that they cannot measure a severity of crash? ...
No, they are as smart as you, but they lack an intellectual attribute that you have: ability to abstract ('Severity', 'Crash'). They also don't have much time to decide - usually 10-20 milliseconds. It takes you longer to blink once.

As far as Video games are concerned, they use at least a 100 times more MIPS than the Airbag system does. Of course they are more intelligent (even if we consider that the comparison is inappropriate), but that intelligence is not linked with liability so anything goes!

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Originally Posted by Tejas Ingle View Post
... The severity of the crash is simply measured in the number of G forces acting on the car. ...
* There is only one g, and that is related with gravity. It is used for comparison only. What is measured by the Airbag sensor is acceleration (+ive or -ive)
* Severity is human intellectual abstraction, cannot be measured, and depends on the viewer's background. If you view dash camcorder recordings of crashes on the net, you will realize that 'severity' has a different interpretation in Russia than in India. There no one will think of a 30-car pile up; in India the same thing would have hit national headlines.

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Originally Posted by Tejas Ingle View Post
... What makes that logic costlier than the car?
You will understand if you try to associate replication of human intelligence and abstraction to Cost / Price of any control system in a car. If you (a human) can think of something, it does not mean it will be possible to practically & economically implement it. The primary focus of the designers of control systems in a car is to implement something practically and economically.
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Old 30th August 2013, 16:31   #93
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Default Re: Airbags deployed after hitting a dog. Understanding why?

A nice video on airbags deployment testing
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Old 22nd September 2013, 18:04   #94
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Default Re: Airbags deployed after hitting a dog. Understanding why?

This has been a thought-provoking, interesting thread. I'm not sure what, if any, conclusions there are. It is a pity that 'groom' left the discussion so early, especially given his stated direct knowledge of such systems.

There seems to be agreement amongst some that this was a faulty airbag system which allowed it to deploy, others suggested it was correct to have done so and was just above the deployment threshold. I wonder how many cars would deploy their bags in just such a situation?

What nobody really discussed was the fact that the driver who hit the dog was placed in a very dangerous position because of the airbag deployment, whether or not it should have happened.
Quote:
Next thing I know there is this huge blast or pop, my chest feel crushed and ears are ringing and the car is full of smoke. I was in a bit of shock and took me a second or so to realize that the air bags have deployed... Once i got my senses back I immediately opened the windows to release the smoke and turned on the hazard sign since i was stationery on the fast lane ... got out of car to ensure I dont get rammed by someone from the back... i realised that the engine was still running and I immediately jumped in and moved the car to safety on the right side off the road.
If the airbag system was faulty, then how many other cars have a faulty system? This is something which is very difficult to check, but faulty airbags/sensors are as dangerous as many other vehicle faults. If the sytem wasn't faulty (the impact being just sufficient to trigger the airbags) then I would suggest there needs to be more effort to try and develop a system which would attempt to prevent this sort of scenario. I'm quite aware of the tiny timespan in which the bag system is required to deploy and of the need to engineer these systems as cheaply as possible - but as it is well demonstrated in emerging markets, car makers often only start fitting safety systems when compelled by law. So the possibility that they may try to improve on them of their own free will is likely to be small. In this highly competitive market, profit is all.

It is quite obvious from the OP that the outcome could have been much less satisfactory had the road been busy. On a single-carriageway road with nothing separating lanes of traffic moving in opposite directions, the outcome could have easily been fatal, not least because by the time he hit/was hit by something significantly larger than a dog, the airbag may have deflated.
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