michinyon:
They have done this a bunch of times on mythbusters, so it can't be too hard. The video is probably
on youtube.
there are a lot of people who have built full size rc cars, but they don't tend to get real deep on how they did it on the mechanical interface side.
it's one thing to run a servo with a small sweep, it's another to build a servo that can push a steering box thru three revolutions. not saying it can't be done, since it clearly has been...only that people rarely document it beyond saying "here it is".
kf2qd:
The whole thing could be done with potentiometers. Multiturn pots at each end. What you would be making is just a bigger version of something similar to a standard hobby servo. Basically - at the steering wheel end you would be "creating" a refernce voltage that you would then compare to the voltage present at the gearbox end. and then itf the voltage is higher or lowere you use that to decide the direction and speed to turn the motor on the gearbox. The difference between the 2 is referred to as the "error voltage" This can be done with linear circuits or Analog to Digital circuits.Using a couple of potentiometers is probably going to be much simpler than using encoders, as absolute encoders would be needed and they get expensive. A good multiturn pot would give good, repeatable feed back.
that's the direction i'm leaning at the moment, unless TR comes back with a reasonably priced solution in a box.
i'm now trying to decide if i can do it without a processor. since i'm just comparing voltages and using the difference to flip a relay in a pure linear relationship, i might be able to take the logic out of it (at least until i decide to get really tricky with it..progressive steering rates or something similar).