Siemens SINUMERIK 840D sl Function Manual page 112

F2: Multi-axis transformations
1.11 Orientation vectors
PHI and PSI angle
Programming of polynomials for the two angles PO[PHI] and PO[PSI] is always possible.
Whether the programmed polynomials are actually interpolated for PHI and PSI depends on:
• POLYPATH("VECT") and ORIVECT are active, then the polynomials will be interpolated.
• If POLYPATH("VECT") and ORIVECT are not active, the programmed orientation
vectors are traversed at the end of the block by a "normal" large circle interpolation. This
means that the polynomials for the two angles PHI and PSI are ignored in this case.
Figure 1-22
The angle PSI can be used to generate movements of the orientation vector perpendicular to
large circle interpolation plane (see previous figure)
Maximum polynomials of the 5th degree permitted
5th degree polynomials are the maximum possible for programming the PHI and PSI angles.
Here the constants and linear coefficient are defined by the initial value or end value of the
orientation vector.
Higher degree coefficients can be omitted from the coefficient list (..., ....) if these are all equal
to zero.
The length of the parameter interval in which the polynomials are defined can also be
programmed with PL.
Points to note
If no polynomial for angle PSI is programmed, the orientation vector is always interpolated in
the plane defined by the start and end vector.
The PHI angle in this plane is interpolated according to the programmed polynomial for PHI.
As a result the orientation vector moves through a "normal" large circle interpolation in the
plane between the start and end vector and the movement is more or less irregular depending
on the programmed polynomial.
In this way, the velocity and acceleration curve of the orientation axes can be influenced
within a block, for example.
Note
Further information on polynomial interpolation for axis motion and general programming is
given in:
References: /PGA/ Programming Manual, Work Preparation
112
Movement of the orientation vector in plan view
Function Manual, 09/2011, 6FC5397-2BP40-2BA0
Special Functions