8.3.6.2 Cubic interpolation
Image 8.35: Interpolation polynomial, 7th degree
Image 8.36: Cubic spline interpolation
MOOG
ID No.: CB40859-001 Date: 11/2020
MSD Servo Drive - Device Help
247
8 Motion profile
As polynomials become more and more unstable as the order of magnitude
increases – that is to say, fluctuate widely between the interpolation points – in
practice polynomials of an order greater than 5 are rarely applied. Instead, large
data sets are interpolated in chunks.
In the case of linear interpolation, that would be a frequency polygon; in the case of
2nd or 3rd order polynomials the usual term used is spline interpolation. In the case
of sectionally defined interpolants, the question of consistency and differentiation at
the interpolation points is of major importance.
8.3.6.3 MSD Servo Drive interpolation types
P No.
Index Name / Setting
Unit Description
370
0
CON_IP
Interpolation type in IP mode
NoIp(0)
No interpolation:
The values are transferred 1:1 to reference
processing in 1 ms cycles.
Lin (1)
Linear interpolation:
In the linear interpolation method the
acceleration between two points is generally
zero. Pre-control of the acceleration values is
thus not possible and speed jumps are always
caused.
SplineExtFF(2)
Interpolation with external pre-control:
Only on request from Moog.
Table 8.18: Interpolation types MSD Servo Drive