On Sep 4, 8:41 am, wrote:
I posted this note on comp.robotics.misc but of course it soon got
lost in all the crap that someone is posting to various groups.

So I thought I would give it a try here.

I am looking for a way to control vehicles somewhat larger than
typical hobby stuff. Say the size of a small lawn tractor.

This would be for steering so I am thinking about using something like
a more muscular servo motor.

I'm aware of hobby style giant servos. They might work but not sure if
they would be beefy enough.

Industrial servo motors seem to be quite different from hobby stuff. I
have one that's rated 128 VDC, has 5 wires running to the motor and a
bunch more off the attached encoder. No real idea what's going on
here.

Searches on servo motor control bring up mostly hobby information
which I am familiar with.

There is the open servo project which might provide part of a
solution. If I can beef up the control so that it can handle something
like a cordless drill motor.

I recenly built a remote control tricycle. I handled the steering
using a regular DC motor controller (Victor 883) and got around the
limit switch problem by building a small spring loaded clutch. (Some
details on my web site under "builders log".)

But I don't really like this solution as there is no automatic
centering feature.

Any other ideas? What do those guys like Mythbusters do for remote
control full size cars?

Thanks for any help.

DOC

Have robots. Will travel. http://www.robot-one.com

I remember one Mythbusters thing that used a very simple system, that
I think would work fine IF the vehicle will not be going very fast.
The servo merely moved fairly high current switches hooked to a
reversible DC motor hooked to the steering shaft. The motor was a
little slow, so steering response was not "sports car steering", but
for a vehicle at walking speeds or so, it should work fine.

Many years ago at work we were building a demo for a "moon rover"
project that used a similar thing, but that was an unstable vehicle
and it was a REAL handful, even at walking speeds, trying to drive it
up ANY hill, 'cause it would spin around and head downhill, but as
long as it is at least a three-wheel vehicle, it should be okay (that
moon rover as a unicycle!).