Anyone know the formula used to control the movement of a simple tank-like vehicle?
To \'steer\' it, you need to alter the force applied the left and right \"wheels\
Here's how I would attack the tank problem.
The center of the tank will probably be moving by the average speed of the right and left tracks. At the same time, the tank will be rotating clockwise around it's center by ([left track speed] * -[right track speed]) / [width].
This should give you speed and a direction vector.
Disclaimer: I have not tested this...