FreeRover has each of its front wheel driven by a NXT motor. Steering is done by a third motor. The speed of the each of the driving motors is dependent of the steering angle. Last night I was wondering if FreeRover could do without a steering motor. If so, this would free one NXT motor for other purposes.

My idea is that the steering angle could be made mechanicly dependent from the (difference in) speed of both steering wheels. The opposite, the speed of both wheels being dependent of the steering angle, can be achieved mechanicly with the use of a differential. I think it can be done, and quite easily as well. If the steering angle can be set without much friction it will do so automaticly if both wheels turn at different speeds. The idea is tempting. Also, I can test it quite easily, i just have to remove one of the gears from the steering gear train. This will free the steering mechanism from the steering motor. I will have to rewrite some of the code though. Now the motor speed is derived from the current steering angle. It must be derived from the aimed steering angle. No big deal.

Are there any disadvantages in terms of stability or the ability to follow the intended path? I don’t know yet. Tests will tell me. It’s going to be a busy evening!