HEIDENHAIN iTNC 530 Service Manual page 650

The nominal velocity value consists of an open-loop and a closed-loop component.
Position control
with velocity
With velocity feedforward control, the machine-adjusted nominal velocity value is the open-loop
feedforward control
controlled component. The closed-loop velocity component is calculated through the following
error. The following error is small.
Using MP 1392 (for the operating modes Positioning with manual data input, Programs run,
single block and Program run full sequence) and MP 1391 (for the operating modes Manual
operation and El. handwheel) you can find out whether the traverse is performed in the
following error mode or feedforward mode (with velocity feedforward control the bits are set to
1).
Figure: Simplified illustration of velocity feedforward control
Unlike operation with following error, the machine manufacturer sets the optimum k
with interpolating axes.
1– 650
S
+
Noml
–
S
Actl
Δ S
Noml
Δ t
v
S
a
S
a
MP1510.x
v
MP1080.x
v
+
Noml
+
HEIDENHAIN Service Manual iTNC 530
factor
v