Hello everyone,,

I'm building rather simple tank chasis simulation, with elements like engine and transmission. Quite a few car physics tutorials where helpfull but it seams that most of them avoid the subject of how differential should properly work. What I mean is this - assumption that drive shaft rotates with the same speed as driving wheels. From what I understand, when car starts to turn and drive wheels starts to turn with a different speed, differential will "cancel" that difference and driving shaft will be spinning just as you drive forward. What I'm trying to understand is how this "canceling" actually happens. in a sense that as rotation of wheels can be "slowed down" by other forces, which can be different on different side. How do I propagate this difference in rotation back into driving shaft? This can't be a simple sum.

In case of tanks it get's interesting. I was looking at this artcile: http://www.gizmology.net/tracked.htm

and if I want to model Double Differential Steering I would need to somehow move torque between separate tracks, calculate propulsion and friction for tank itself, calculate torque effecting tracks and then calculate new angular velocity of driving shaft from those effects.