[GeeTwo]

When you have all wheels going forward or reverse, the rate of acceleration for mecanum is calculated essentially the same as that of traction wheels as long as you don't lose traction and "spin out". The maximum rate of acceleration (at low speeds) is going to be equal to the coefficient of friction in rolling motion times gravity. For most of the FRC mecanum wheels is going to be about 0.7 * 32 fps/sec, or 22 fps/sec. Because of the way mecanums interact with the floor, the maximum strafing acceleration is a bit lower than forward, and on a 45 degree bias, it will be off about 30%. Curiously, the fastest "acceleration" you can manage with mecanums is to spin; all of the wheels engage with the floor just as well as they ever do, all at the same time.