Aerotech UNIDEX 600 Series, User Manual

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U600 User’s Guide AerTune
Version 1.4
Aerotech, Inc.
5-7
5.3.3. Determining the Maximum Acceleration of an Axis
The maximum acceleration of an axis may be calculated or determined empirically via the
AerTune utility after your axis has been fully assembled (to other axes), configured, and
tooling/parts loaded. The acceleration is increased until the axis produces a 10 volt torque
command during acceleration. This indicates that the amplifier has saturated (full on),
indicating that the axis is accelerating as fast as possible with the current load.
In the example below, we will determine the maximum acceleration in machine counts /
second / second, since this can easily be converted to user units / second / second for the
AccelRateIPS2 (AccelRateDPS2 for rotary axes) task parameter. You could also
determine the maximum acceleration (in time) to a given velocity. However, this is
dependent on the programmed speed.
Other system considerations like motors, ball-screws, bearings, encoders, stiffness,
structural resonance, move profiles, and duty cycle may require a lesser value for
optimum and reliable performance. Exceeding the maximum acceleration
specifications of system components will cause damage.
1. From the “Plot” menu, select “Velocity Command”, “Velocity Feedback”, and
“Torque” to be displayed.
2. Set the ACCELMODE and DECELMODE axis parameters for linear or
sinusoidal rate-based acceleration. Rate-based sinusoidal acceleration is
recommended.
3. Select “Update Step Move Parameters” from the “Trigger” menu.
4. Enter a speed and distance (in machine counts) to produce a trapezoidal velocity
profile that will not encounter an end of travel limit. A trapezoidal velocity
profile implies a profile at which the axis reaches constant velocity.
5. Press the Auto Cycle button.
6. Increase (or decrease) the ACCELRATE field on the “Update Step Move
Parameters” window until the axis produces a 10 volt torque command during
acceleration.
7. The value in the ACCELRATE field is the maximum rate at which the axis can
accelerate with the current load.
WARNING