Acceleration
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To allow the stepper motor to turn at a frequency higher than the start/stop frequency, it must be accelerated via a frequency ramp. The frequency cyclically increases by the value of the acceleration. If the acceleration is too high, the stepper motor can no longer overcome the moment of inertia and loses steps. The stopping process is carried out with the same frequency ramp.
The optimum acceleration ramp follows an exponential function so that the ramp initially rises steeply and then asymptotically runs up to the target frequency. The run-up ramps most frequently encountered are, however, linear ramps or combined linear ramps with different frequency/time jumps in practice as these still easy to generate via microprocessors without requiring too large a program memory. The dynamics are not significantly impaired in the case of linear ramp compared with the exponential ramp.
