[Kevin Sevcik]

It would help immensely if you could post your code, or a snapshot of the relevant portion of your code. As it is, my questions are, which divide function are you using, floating point divide, or "Quotient and Remainder"? Also, your code as described, will accelerate faster at the beginning and slower towards the end. I don't want to think of how long it'd take your robot to get up to the joystick's command doing it that way. It'd be a very long time, however.

The usual way to do this is to pick a specific number to add to the motor command every loop, until you get to the joystick command. So you'd just add (or subtract), say, 0.001 to the motor command on every loop, and then make sure it's not larger (or smaller) than the joystick value.