golf cart steering

[ajd]

Originally Posted by EricH

Take away the "might" in that. Is it doable? Yes, but not easily. (Golf carts use steering like cars; modding that would need a second motor and locking the front wheels at minimum, let alone control setup.)

You could still use rack-and-pinion steering with such a scheme; the input would just be tank drive. You would have to come up with a mechanical way to convert between the two representations, though, unless you consider drive-by-wire solutions.

[biojae]

Originally Posted by ajd

You could still use rack-and-pinion steering with such a scheme; the input would just be tank drive. You would have to come up with a mechanical way to convert between the two representations, though, unless you consider drive-by-wire solutions.

Converting the tank drive commands to velocity and steering would not be too hard.

Velocity = (L + R) / 2
Turn      =  (L - R) / 2

Though, the cart won't react the same way as a First robot.
Mainly because the cart can't turn in place, only in arcs.

I would keep the steering control type as close to the original as possible (ie a turn-table would be fine because it is still a type of rotary interface that has a one-to-one relation with the cart's steering, like the original steering wheel)

[EricH]

Originally Posted by ajd

You could still use rack-and-pinion steering with such a scheme; the input would just be tank drive. You would have to come up with a mechanical way to convert between the two representations, though, unless you consider drive-by-wire solutions.

If it's a RWD, add a motor. If it's 4WD or front-wheel drive, it's a lot harder.

It's simpler if you can just add a second steering wheel near foot level.

[PAR_WIG1350]

what about an arm or arms directly attached or geared to the steering wheel that allow it to be controlled by moving one's knee from side to side.
a Y shaped bar that straddles one's knee is both cheap and effective gearing could be used to amplify inputs, since a direct connection wouldn't be very agile without having to lift your knee, and then you wouldn't be able to operate the pedals.

[Dick Linn]

I'm the one who steered Cliff to this site, so let's do what we can to help out. I'm sending Cliff the contact info for Patty Cook, who can no doubt hook him up with some of the team contact info.

[jspatz1]

I fully agree that the right input method is more critical than the mechanical actuation method. A turntable/floor wheel under the left foot feels like the right input solution to me. Fairly natural, easy to get on and off of, no strange input devices in the way elsewhere. Could even leave the normal steering wheel in place so it is still usable by anyone. The lower leg is pretty strong compared to hands and wrists, and should be able to duplicate the effort required for normal steering. The golf carts I've used steer very easily, so perhaps this could be tied directly into the existing linkage. If he has full strength in his legs then it really seems like there is enough strength in the leg to steer without an actuator or assist. But if some actuator or power assist is needed, why not borrow the power steering method for cars that is already highly developed and readily available? I'll bet a good mechanic or car hobbyist could select and adapt the power steering components from a salvage yard that would do the trick. Sounds like an interesting project, wish I had time for it myself.