[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.