Consultants say interference in vehicle electronics is possible - Page 2

Just love how the factory engineers and federal regulators can examine
a system for a couple of hours and then call it clean. I've spent
literally weeks on the integration test bench running full bore with
top-notch test equipment to tease out rare failure modes, both
software and firmware. The bugs relating to race conditions, cross-
domain timing errors, and sensitivity to normal component tolerances
are especially entertaining--NOT!
 
--
Jack Myers / Westminster, California, USA
 
Postfix...a computer term meaning "sendmail is too hard for me"

Jack Myers wrote:

I would think that, together, the NSTSA and Toyota engineers have plenty
of knowledge and experience with this sort of testing and of Toyota's
system. They may know what they are doing when it comes to looking for
problems. In addition, the software errors that exist in the system
(yes, I am nearly certain there are some) would be able to examined
elsewhere (because the software in the system is a copy).

The type and amount of testing might be perfectly fine to get the
information they need.

Jeff

dr_jeff wrote:
snip

But checking out someone else's code is a real bitch.  Several times I
was given someone else's code to use as a starting point for a similar
program. I usually ended up throwing it away and doing my own from
scratch because I was convinced it would take less time.

Reverse engineering is never easier than forward engineering.  It
depends too on how well project management enforces documentation
rules/guidelines.

Even so, one problem is that once you understand someone else's code
well enough, you can get trapped into thinking like them, and overlook
that surprise condition that the original coder overlooked :-(

Toyota may, but the NHTSA sadly does not.  On the other hand, they may
be able to call in some folks from the NTSB, for example, who do.


It's a lot easier to find odd conditions with code reviews and verification
than with exhaustive testing.  But it's also very, very expensive.
--scott
--
"C'est un Nagra.  C'est suisse, et tres, tres precis."

In this case, I doubt it.  In my opinion, the fault (if one exists) is much
more likely with the electronic hardware platform than with the software
running on it.  You can test the code all you want, but it won't be until
that 'race condition' or similar problem is found in the hardware that the
engineers can even begin to understand why the process doesn't act as
expected.

Absolutely. When I was in college we spend a solid week learning how to
design input sets to check for faulty coding. It is in no way trivial.


--
(setq (chuck nil)  car(chuck) )

Yep.   Hopefully the reason that the NHTSA bought up the computer board is
so they can spend the next month or two with it tied into a logic analyzer.

Airplanes have seen the same sort of interference from cell phones, but it
doesnt seem to be very repeatable and is normally fleeting with no residual
results.

I think that internal software or electronic hardware platform errors are
far more likely that glitches due to cell phone signals, sun spots, etc...

I suspect you may be correct.
At this point it is not certain what has really happened in these claimed
unintended acceleration cases.

I think glitches caused by the presence of free-and-easy tort are the most
likely of all.


--
Tegger

Most definitely.  Regardless as to whether or not there are real problems,
the trend in reported problems related to news coverage of reported problems
/ recalls clearly demonstrates that most of the complaints are linked to
opportunity.

Cell phones have a voltage spike just as the call is being connected.
There was a Mythbusters episode that showed that.

BTW if there's anyone wondering, I am the same poster as fred. I created several
nicks to avoid a stalking troll. It didn't work in the long term. Thanatoid
probably knows what I'm talking about as he's dealt with the twit as well.

--
(setq (chuck nil)  car(chuck) )

15 yr ago I read of 1 car in USA using auto cruise control drtve
past a truck using CB radio, this car @ once got unintended
acceleration, this driver switched off his auto cruise & ended this
problem.  He told medias to warn users of auto cruise control
against CB radios.

wrote:


Maybe fifteen years ago, but EMI suppression has advanced since then in
the automotive industry and many other industries too.
--
 

wrote:


  There was  ONE model of cruise control I heard about that was
extra-fussy about CB Radio interference and IIRC it was OK with a 4
watt unit installed in the vehicle, but a 100 watt Linear amp in a
vehicle within a couple hundred feet could "jam" it.

Those cruise control units were VERY primitive compared to anything on
the market today. The affected unit was made by ARA if I remember
correctly and the problem only occurred if using the engine speed
sensor option instead of the magnets on the driveshaft - and that was
closer to 20 or 25 years ago (very early 1980s - early Chevy Citation
comes to mind.

clare@snyder.on.ca wrote:

Cruise control usually used vehicle speed rather than engine speed. If
the car kicks in a lower gear (e.g., when going up hill), then the car
would slow down to keep the engine speed constant.

I am not saying that there weren't any cars that used engine speed
rather than vehicle speed, but I would think that there are few.

Jeff

On 3/25/10 8:52 PM, in article
wrote:


Every car I have owned, starting with the 1960 Chrysler Imperial, has been
equiped with cruise control.  They are/were all designed to regulate vehicle
speed, not engine speed.  I can't remember any instance of a system that
attempted to regulate engine speed, though I do remember some aftermarket
kits in the 60's & 70's that were simple mechanical throttle controls.  

E. Meyer wrote:

No one was claiming any factory cruise control worked by keeping engine
speed fixed.  Aftermarket cruise controls had that option though, and for
cars with standard transmission it was a reasonable choice to tap off the
coil signal rather than affix magnets to the driveshaft.  The only down-
side was if you set the cruise to 60 in 5th gear, and resumed in 4th you'd
be doing 70 or so, depending on gear ratios.

On 3/26/10 8:06 AM, in article EZ-dnRV2qrn7LDHWnZ2dnUVZ_oGdnZ2d@posted.visi,


All the aftermarket kits (as well as factory add-on kits) I encountered for
manual shift cars all passed the speedometer cable through the unit for
speed sensing and added a second cut off to the clutch pedal (along with the
brake pedal cut off present on automatic trans units).