# Hi there! New to the forum, with a very interesting project...



## Woodsmith (Jun 5, 2008)

This would be an interesting project, I'd really like to see this working!


My thoughts are that wheel chair motors wouldn't be up to it and the wheel chair controller would be too small.

The golf buggy axle with steering brakes would work but you could find that the diff gears would soon give up after a few high power turns.

I would suggest looking for a small forklift, the type that has two small (7" diameter) geared motors, one for each drive wheel, and use that.

I'll try and find an image if you are not sure what I mean.


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## PStechPaul (May 1, 2012)

Looks like a cool project! I would suggest using a 4 axis joystick for control. It would require a microcontroller and some circuitry and programming to do it right, but essentially you just need to provide two drive signals for two separate controllers, and use the forward/reverse axis added to the left/right axis, with enough "deadband" so that there will be no drive signal until the lever is moved significantly from its center position where it returns by spring action. 

It is possible to set up a VFD for a three phase motor to run both forward and reverse with a +/- 5V signal. So if you had two controllers, one for each side, you could just add the voltages together and be able to achieve zero turn radius by spinning one side forward and the other in reverse. Basically the drive voltages would be:

Left = Y - X
Right = Y + X

So if the X axis (L-R) is zero, you just go forward or reverse. And if the Y axis is zero, you turn in place at a speed equal to the X voltage which will be forward for one and reverse for the other. I have a video showing how I connected a joystick to a VFD and motor:


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