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Toyota's Engineering Process and the General Public
Doofus writes "The Washington Post has published in today's paper an article titled 'Why it's so hard for Toyota to find out what's wrong' by Frank Ahrens on the Toyota situation and the difficulties of adequately conveying to Senators and Representatives — most of whom are non-technical — the debugging process. Ahrens interviews Giorgio Rizzoni, an 'expert in failure analysis' at Ohio State, who describes the iterations of testing that NHTSA will likely inflict on the Toyota sample cars they have purchased, and then moves into the realm of software and systems verification: 'He explained that each vehicle contains "layers of computer code that may be added from one model year to next" that control nearly every system, from acceleration to braking to stability. Rizzoni said this software is rigorously tested, but he added: "It is well-known in our community that there is no scientific, firm way of actually completely verifying and validating software."' Ahrens ends the piece with a quote from a 2009 LA Times interview with former UCLA psychology professor Richard Schmidt about how user reports are often unreliable: 'When the driver says they have their foot on the brake, they are just plain wrong. The human motor system is not perfect, and it doesn't always do what it is told.'"
Toyota is currently planning an event to challenge evidence presented by professor David W. Gilbert that called into question Toyota's electronic throttle system.
Why exactly is there a congressional case going on about this? It becomes even more worrying when you realize that the US government has a controlling interest in most of Toyota's competitors in the USA. In short, why, in a country where states are going bankrupt, privacy is an illusion, healthcare reform has boiled down to if you are pro or anti Obama, rampant spending and tax increases. In short, why do I care about this? File a class action lawsuit and let the courts settle it. Nothing is worse then a bunch of politicians knowing nothing about engineering, with stock in competitor's companies and large problems they haven't solved wasting their time with this crap.
Taxation is legalized theft, no more, no less.
When the driver says they have their foot on the brake, they are just plain wrong. The human motor system is not perfect, and it doesn't always do what it is told.'
This was true with Audi in the 80's, when 60 Minutes did a report where, among other things, they faked a car accelerating out of control (the car was modified extensively.) And yes, a large number of drivers, particularly the elderly, hit the wrong pedal all the time.
However, there are cases where driver reports are plenty accurate. A great example of this would be the problems Volvo V70R and S60R owners have with brake failure while going up hills.
I've experienced it three times in the 6 months or so that I've owned my car. Each time, I was headed up a hill towards a stop sign, put my foot on the brake, and there was nothing there- I had to push so hard I was pulling against the steering wheel for leverage. This is a car with big, high-performance brakes that can stop on a dime.
Volvo claims there's no problem, despite numerous reports on the V70R.com and Swedespeed forums. No other models demonstrate the behavior.
Please help metamoderate.
There's even hardware to do it. dSpace sells some very nice (and very expensive) hardware to do testing. You can setup scripts to test almost any scenario. It'll fake out all the basic sensors and then you can test to see what happens when you hit the brake at 10 mph, 20 mph, 30 mph. You can do burn in tests. Software is very very repeatable. You can often trace right through the Simulink model and find out what is going on.
In the latest versions of CANape you can even view your Simulink Model EXACTLY how you built them and add all of your signal channels to it. If there is a bug or people are experiencing problems, it takes all of an hour at most to figure out what is going on and what is causing it.
And given the short cycle time, you don't have time to rewrite everything. Every company that uses Simulink for models even has verified and validated library blocks. We have a "C to K" block (because one isn't built in). That automatically matches In & Out data types, etc. We have low pass filters that are designed to our companies standards....
And we have engine control models that have been ported from Assembly that have been used for 30 years that 'work'. We're not going to throw that all out the window every development cycle.
Previous comments on how Simulink is used to write code in companies that use it.
SAE Paper on how Caterpillar uses auto coding generation to write their stuff.
... being in control of braking and acceleration.
If you disagree with me on social issues, then it's pretty clear that you are a narrow-minded bigot.
The most relevant thing I've read about the problems with Toyota vehicles is this quote from the bottom of page 3 of that PDF linked above:
"... it was determined that [Toyota] Electronic Control Module (ECM) malfunction detection strategies were not sufficient to identify all types of fundamental APP sensor and/or circuit malfunctions. Some types of Electronic Throttle Control (ECT) circuit malfunctions were detectable by the ECM, and some were not. Most importantly, the Toyota detection strategies were unable to identify malfunctions of the APP sensor signal inputs to the ECM. APP sensor signal circuits must be undeniably correct to electrically convey the appropriate driver commands to the ECM."
Next paragraph:
"With the two APP sensor signals shorted together through a varying range of resistances, all four Toyota vehicles tested thus far reacted similarly and were unable to detect the purposely induced abnormality. The types of signal faults introduced into the APP circuit should have triggered the vehicles' ECM to illuminate a warning lamp within seconds."
Bottom of page 4:
"In addition, the shorted APP signal circuits were connected momentarily to the sensor's five-volt supply circuit with the vehicle in drive. In all test vehicles, the ECM did not set a DTC and the engine speed increased rapidly to full throttle. This result shows that unusual or sudden unintended acceleration of the vehicle was possible in the ETC test vehicles."