scott wrote:
>> ...not to mention traction control... ;-)
> 
> Er yeh, that's what I meant by wheel-spin.

ABS turns the brakes off if you brake too hard, traction control turns 
the drive off if you accelerate too hard. At least, as far as I know... ;-)

> OOC I looked up the 
> instructions for how a dealer fits the "USB Audio" upgrade to my car (I 
> was just wondering if the cables were already there and I simply needed 
> to fit a suitable plug - sadly not).  Anyway, it appears my car has a 
> network of fibre optic cables o_O.

Well... less suseptable to EMI and corrosion?

> To fit the upgrade, apparently 
> involves ripping out half the car, making some connection to a box of 
> opto-electronics in the boot, then fitting a "USB hub" under the drivers 
> seat and fitting the USB socket in the centre console, and of course 
> fitting cables between all of them.  The 250 pound price tag doesn't 
> sound so bad now!

LOL! Yeah. Apparently modern cars have quite big wiring looms inside 
them now. I remember one guy did some work on his own car, and then had 
to pay for an accredited shop to confirm that the airbag detonation 
system is still operating within spec.

Seriously though, you'd think they'd just put lots of spare cable in 
there so you can add new connections without rearranging half the car...

>> The part I can't figure out is that, as far as I can tell, hooking up 
>> a motor that turns the steering wheel in the same direction as you're 
>> trying to turn it should generate a positive feedback loop. I can't 
>> figure out how turning the wheel doesn't cause the powerful motors to 
>> rip the wheel out of your hands and put the car into full lock before 
>> snapping the steering column in half...
> 
> If you simply program the motor to apply the same torque you are 
> applying with your hands to the wheel, then there is no feedback, it 
> will just feel like it takes half the force to turn it.  Of course in 
> reality it is more complex, the multiplier is probably dependant on 
> speed, and maybe other factors like how sharp you are turning.  And 
> maybe there is some limit the torque you apply needs to go above before 
> the motor kicks in?

Oh, it's programmable? I thought it was a purely mechanical system...

Even so, how can you "sense" the amount of force the user it putting 
into the system seperately from the amount of force the power assist is 
putting into it? I can't think of a way of doing that.

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