July 2013 6.8 The control loop 815
You must adjust the velocity feedforward value to the dynamics of the
machine:
With MP1060.x you define the acceleration or the steepness of the velocity
curve.
In MP1090.x, you limit the jerk for the Program run full sequence and
Program run single block modes of operation. Just as the acceleration is
the rate of change in velocity, the jerk is the rate of change in acceleration.
The greater the entered value, the more the system will tend to oscillate.
With MP1085.x you limit the axis-specific jerk for path contours in the
Program Run, Single Block, Program Run, Full Sequence and MDI
operating modes, as long as the feed rate is not equal to FMAX or is less
than the value in MP1092. Until now, this value was set for all axes in
MP1090.0.
The value in MP1090.0 will continue to be used as the maximum
permissible jerk for motions in all axes. Even with interpolating axes this
value is the maximum jerk for the entire machine.
The formula shown can be used to calculate a guide value for MP1085. The
formula is conceived for the calculated jerk to be large enough that the
acceleration of the axis is not impaired.
Input: 0.1 to 1000 [m/s3]
With MP1086.x you limit the axis-specific jerk for single-axis motions at
rapid traverse in the Program Run, Single Block, Program Run, Full
Sequence and MDI operating modes, if the feed rate is FMAX or is greater
than the value in MP1092. Until now, this value was set for all axes in
MP1090.1.
The value in MP1090.1 will continue to be used as the maximum
permissible jerk for rapid-traverse movements in all axes. Even with
interpolating axes this value is the maximum jerk for the entire machine.
The formula shown can be used to calculate a guide value for MP1086. The
formula is conceived for the calculated jerk to be large enough that the
acceleration of the axis is not impaired.
Input: 0.1 to 1000 [m/s3]
0: Not active (then also for FMAX value in MP1085.x)
MP1085 ≥
MP1060
2
· 60000
MP1010
MP1086 ≥
MP1060
2
· 60000
MP1010
HEIDENHAIN recommends entering the permissible jerk for each axis in
MP1085.x and MP 1086.x. This way the jerk is based on the weakest axis
participating in a motion. The value in MP1090.x should be chosen
correspondingly greater than the largest axis-specific jerk (or the value 0
should be entered to omit limiting by MP1090.x) so that the control has the
possibility of using the optimum jerk and therefore the optimum
acceleration for interpolating axes.
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