I have driven a piece of farm equipment (bin carrier) which has a pedal that works this way. The pedal is on a pivot and instead of depressing the whole pedal you press on the top to go forward and the bottom to go back. Braking is a simple matter of pressing the pedal in the opposite direction you are going (though normal mechanical brakes are also present as backup).
I found the system to be rather touchy. When coming to a stop it was quite easy to overcompensate and start oscillating back and forth. It was quite fun to drive though, and for the kind of work a bin carrier does the ability to reverse without changing gears is very useful.
Incidentally, in order to achieve this continuously adjustable drive a diesel engine runs at a constant RPM turning a hydraulic pump which in turn drives hub motors in each wheel. The whole thing makes a very distinctive sound as it drives around.
I found the system to be rather touchy. When coming to a stop it was quite easy to overcompensate and start oscillating back and forth. It was quite fun to drive though, and for the kind of work a bin carrier does the ability to reverse without changing gears is very useful.
Incidentally, in order to achieve this continuously adjustable drive a diesel engine runs at a constant RPM turning a hydraulic pump which in turn drives hub motors in each wheel. The whole thing makes a very distinctive sound as it drives around.
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