Singular Positions And How They Are Handled - Siemens SINUMERIK 840D sl Function Manual

13.7

Singular positions and how they are handled

The calculation of the machine axes to a preset position, i.e. position with orientation, is not
always clear. Depending on the machine kinematic, there may be positions with an infinite
number of solutions. These positions are called "singular".
Singular positions
• A singular position is, for example, characterized by the fact that the fifth axis is positioned
at 0°. In this case, the singular position does not depend on a specified orientation. The
fourth axis is not specified in this position, i.e., the fourth axis does not have any influence
on the position or the orientation.
• A singular position also applies for articulated arm and SCARA kinematics if the third axis
is at 0° or 180°. These positions are called leveling/diffraction singularity.
• Another singular position exists for articulated arm kinematics if the hand point is above
the rotary axis of axis 1. This position is called overhead singularity.
Extreme velocity increase
If the path runs in close vicinity to a pole (singularity), one or several axes may traverse at a
very high velocity. Alarm 10910 "Irregular velocity run in a path axis" is then triggered.
Behavior at pole
The unwanted behavior of fast compensating movements can be improved by reducing the
velocity in the proximity of a pole. Traveling through the pole with active transformation is
usually not possible.
Special Functions
Function Manual, 09/2011, 6FC5397-2BP40-2BA0
TE4: Transformation package handling
13.7 Singular positions and how they are handled
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