Arduino precise timing question
I have a robot that has to turn by an exact angle. After thinking for a long time I came to an ugly solution of getting two continuous rotation servos turn the two bearing wheels in opposite direction for a particular time. I timed something like twenty full rotations and made the robot calculate the time needed for turning n degrees. However, there is some time needed to connect the servos and for them to start turning, so after about 10-20-30 robot turns the mistake runs up quite high.
Does anyone have any ideas of how to calculate the 'speeding up' constant I have to add to every turn time? Quite anything is appreciated, I've been thinking for two months (but not quite intensively:)).