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Toyota recalls: Deeper engineering implications

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Owjie
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re: Toyota recalls: Deeper engineering implications
Owjie   2/17/2010 3:47:39 AM
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As you may know toyota has two major recalls, one for sticky gas pedal(mechanical Failure) and the other regarding the interference of the floormat with accelerator pedal.The last stage in floormat recall is to reflash the ECM. The new software will cut off the fuel from engine if the both pedal pressed simultanously. This feature is already used in Camry hybrid software so the reflashing would not be necessary.

BobGroh
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re: Toyota recalls: Deeper engineering implications
BobGroh   2/16/2010 6:50:34 PM
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Just one little nagging thought: what if the 'sticking throttle' problem is NOT due to what the a 'sticky' mechanical. Or is not totally due to that problem source. What if this is a multiple source problem (e.g. the carpets and the 'sticky' pivot point and ??????). There is one fix that should, in my opinion, be part of the solution - a software patch to link the brake pedal to the throttle mechanism. Some other cars use this - why not Toyota? They are patching problems that might cause the throttle to stick - they do not seem to be tackling the question - what do you do WHEN the throttle is applied AND you are trying to brake! This should be a component of any fix for this problem.

rpcy
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re: Toyota recalls: Deeper engineering implications
rpcy   2/16/2010 6:37:37 PM
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Bill, you're right about the law of large numbers, and you're right about the pundits not knowing what they're talking about. My only quibble would be that for a mechanically sticking accelerator pedal, this particular company had a gigantic experience base with getting that right in the past. What did they change such that it's not right any more? Did they have a good reason to mess with something that was working? If so, I agree with you. If not, then they took a risk which now seems not to have paid off. Was it still a risk worth taking? Only Toyota could know that. This is what the pundits are missing -- engineering is the art of combining what is known to work with new elements so as to make something that is better than what existed before. If you take risks, as engineers must, then sometimes you'll lose. The only question is whether it was an intelligent gamble or a gaffe.

HML_EE
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re: Toyota recalls: Deeper engineering implications
HML_EE   2/14/2010 10:41:23 AM
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There is no doubt Toyota's engineering and test capabilities are very competent. Their manufacturing processes and quality control are probably second to none. However, in all the talks about root-causes, more testing, more robust designs, etc, etc, there is little mention of failure mode effects analysis (FMEA). If the failure modes are identified and mitigations implemented for the most severe ones, the probability of a vehicle with a stuck gas pedal killing all its occupants would be much less than what we have experienced. This is a single-fault-condition that could have been identified and mitigation(s) put in place to prevent (or at least significantly minimize the probability of) an accident. It is unreasonable to use zero-defect as the first line of defence in a safety related situation. Yes, this will add engineering time and cost to the development budget. But, I am fairly sure this cost is far less than what Toyota is spending on the recalls and PR damage control.

Neel Mathews
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re: Toyota recalls: Deeper engineering implications
Neel Mathews   2/11/2010 5:51:14 AM
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The issue is every sigma adds cost and complicates the entire design to delivery team's life. We need to find a simpler quality system which leave engineers to do more technical work than too much of documentation work. I think Toyota need to do a root cause analysis and pin point exactly what part of quality system lost control and why?, - a true 'why' analysis is need, after all having so much of quality system implemented.

Jimmymac0
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re: Toyota recalls: Deeper engineering implications
Jimmymac0   2/11/2010 4:08:05 AM
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Software issues are rampant. As we begin to depend on SW vs HW to stop a car safely we buy into the same BS we see at Microsoft. Lousy code and pitiful support. Get real folks. Algorithmic experts are the greatest. But given my experience with them in computational litho world === I gotta wonder if my car will stop! jimmymac

Mapou
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re: Toyota recalls: Deeper engineering implications
Mapou   2/10/2010 9:18:25 PM
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green_ee wrote, * "Complexity: It's difficult/impossible for the human brain to comprehend/predict all possible scenarios, sources of failure, and appropriate fail-safe actions. These get even more complex with multiple-simultaneous failures." * I agree with you about the impossibility of the human brain to predict all possible consequences. However, I am convinced that, given the right software model and adequate path discovery tools, all possibilities could be discovered. The reason that this is not done in practice is that our current software model is hopelessly flawed. There is a correct way to do things but it will require courage more than anything else to switch paradigms.

green_ee
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re: Toyota recalls: Deeper engineering implications
green_ee   2/10/2010 9:07:32 PM
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I'm sure there are plenty of fingers to point: 1. Time-to-market pressure: There simply isn't enough time to test pre-production units through all possible scenarios. Despite careful planning, technical programs almost always experience schdule overruns, and at some point, things aren't allowed to slip any further. You go with what you have. 2. Cost pressure: Technical programs are often understaffed, and underskilled with less-experienced (ie, cheaper) engineers. 3. Complexity: It's difficult/impossible for the human brain to comprehend/predict all possible scenarios, sources of failure, and appropriate fail-safe actions. These get even more complex with multiple-simultaneous failures. 4. Material costs: Subcontracted manufacturing to the lowest-cost provider may cause problems later on. At some point, corners get cut to reduce costs, and those cuts can affect quality & reliability. 5. Competitor-bashing: Are Ford, GM, Chrysler, etc offering any assistance to Toyota to resolve this problem ? Hah! I doubt it; Could they be stoking the bad PR fire (behind the scenes, of course) against Toyota ?

bcarso
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re: Toyota recalls: Deeper engineering implications
bcarso   2/10/2010 8:36:37 PM
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What bothered me so much about the developments in this crisis was the complete refusal, initially, of Toyota to even allow for the possibility of software/firmware/electronics being involved. If it turns out to be nothing more than the sticky potentiometer-pedal and before that the interference from floor mats, the idea of not even allowing for the possibility of anything else strikes me as dysfunctional at best. Mapou's general direction is astute it seems to me. I hope that it gets more press and real action, whether or not fallacies of software testing wind up being involved in these specific crises or not. Brad Wood

djhk
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re: Toyota recalls: Deeper engineering implications
djhk   2/10/2010 7:56:27 PM
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The hand brake is not strong enough. Just cut off the fuel supply. Most cars have an electric fuel pump. A simple switch can halt the car.

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