HEIDENHAIN iTNC 530 HSCI - Feedback Control with Velocity Feedforward

July 2013 6.8 The control loop 835
Feedback control
with velocity
feedforward
The nominal velocity value consists of an open-loop and a closed-loop
component.
With velocity feedforward control, the machine-adjusted nominal velocity
value is the open-loop controlled component. The closed-loop velocity
component is calculated through the following error. The following error is
small.
In most cases, machines are controlled with velocity feedforward, since it
makes it possible to machine exact contours even at high speeds.
For the Positioning with manual data input, Program run, single block
and Program run, full sequence operating modes:
 Switch on the velocity feedforward control with MP1392.
For the Manual and El. Handwheel operating modes:
 Switch on the velocity feedforward control with MP1391.
Block diagram:
Analog axes (control via CMA-H):
For stationary axes, the integral factor has an additional effect (MP1080.x). It
produces an offset adjustment.
Digital axes:
There is no offset. MP1080.x has no function.
v
S
a
+
–
S
a
+
+
v
Δ t
MP1510.x
MP1080.x
v
Noml
Δ S
Noml
S
Noml
S
Actl