[tinwhiskers] Re: Expert recreates Toyota sudden acceleration
- From: Rod <rod.dalitz@xxxxxxxxxxxxxxxx>
- To: tinwhiskers@xxxxxxxxxxxxx
- Date: Thu, 25 Feb 2010 20:46:13 +0000
On 25 Feb 2010, at 19:29, Clif Brick wrote:
> What does that have to do with tin whiskers? Are you proposing that tin
> whiskers are causing the Toyota problem?
Not necessarily, but tin-whiskers are one of many ways electronic control can
go wrong.
Where Toyota and no doubt others have failed is in not providing an intuitive
fail-safe. Especially with automatic transmission, where interlocks and no
clutch may make it impossible to disengage or switch off the engine, the driver
must be able to overcome unwanted acceleration - most simply, by hitting the
brakes in the same way cruise control drops out.
Whether the cause is tin-whiskers, or EMI, or a wiring fault, or a software
bug, or wrong materials for the accelerator pedal parts, is not so important.
Any of those may be true, and upset electronic control. The original mechanical
control was not only simple, it had a hundred years of development and
experience behind it, and the principle of steel cable working against a spring
in the carburettor means that many failure mechanisms shut down the throttle -
except the return spring, which is easily duplicated.
Electronic controls, for engine, brakes, or perhaps in the future steering, are
a kind of creeping development which can easily move beyond what is known to be
safe. These require an order of magnitude more care, in system thinking.
regards, Rod
rod.dalitz@xxxxxxxxxxxxxxxx
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