Jerk Filter (Position Setpoint Filter, Axis-Specific); General Information - Siemens SINUMERIK 840D Function Manual

B2: Acceleration and jerk
12.2 Functions
Example
Example of parameter assignment:
● MD32437 $MA_AX_JERK_VEL0 = 3000 mm/min
● MD32438 $MA_AX_JERK_VEL1 = 6000 mm/min
● MD32439 $MA_MAX_AX_JERK_FACTOR[AX1] = 2.0
● MD32439 $MA_MAX_AX_JERK_FACTOR[AX2] = 3.0
● MD32439 $MA_MAX_AX_JERK_FACTOR[AX3] = 1.0
Effect
● The speed-dependent jerk adaptation is active for the 1st and 2nd axis, whereas the
function for the 3rd axis is not active.
● The parameterized jerk is effective at axis velocities in the range of 0 to 3000 mm/min.
● The maximum jerk is linearly increased for axis velocities in the range 3000 mm/min to
6000 mm/min.
● The maximum permitted jerk of the 1st axis is, for axis velocities greater than 6000 mm/min,
increased by a factor of 2 - for the 2nd axis, by factor of 3.
● The parameterized values apply in each dynamic response mode.
12.2.18

Jerk filter (position setpoint filter, axis-specific)

12.2.18.1

General Information

Overview
In certain application scenarios, e.g. when milling free-form surfaces, it may be beneficial to
smooth the position setpoint characteristics of the machine axes. This enables the surface
quality to be improved by reducing the mechanical vibration generated in the machine.
To smooth the position setpoint characteristic of a machine axis, a jerk filter can be activated
at the position controller level, independent of channel- and axis-specific jerk limitations that are
taken into account at interpolator level. Jerk limitation can be set using the following machine
data, for example:
● MD20600 $MA_MAX_PATH_JERK (pathrelated maximum jerk)
● MD32431 $MA_MAX_AX_JERK (maximum axial jerk for path motion)
All position setpoint filter types have a lowpass characteristic, and always round a contour at
the center of the curvature (towards the inside). Larger time constants or lower filter frequencies
round the contour more significantly; however, that also means that machine resonance points
(machine oscillation) are excited less. A compromise must always be found between an
adequate damping effect and contour accuracy.
The damping effect can be monitored using the positioning response, the contour accuracy,
using a circularity test, for example.
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Axes and spindles
Function Manual, 06/2019, A5E47437747B AA