Detailed description
2.5 Optimization of the control
Basic logic functions: Velocities, Setpoint/Actual Value Systems, Closed-Loop Control (G2)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
71
2.5.2
Position controller position setpoint filter: New balancing filter
For speed and torque feedforward control
Application
With feedforward control active, the position setpoint is sent through a socalled balancing
filter before it reaches the controller itself. It is thus possible to feedforward control the speed
setpoint at 100%, without resulting in overshoots when positioning.
Functionality
Until now, it was possible to compensate the negative effects of the balancing filter (a low
pass with settable time constant), which has remained unchanged since SW 1 and which
has admitted instead of an overshoot also undesired undershoots of some 10 micrometers,
as follows:
•
Setting a compromise of overshoots and undershoots
•
Setting the positioning slightly overshooting and reducing the amplitude of these
overshoots by way of position setpoint signal smoothing and jerk limitation
•
Setting a speed controller with reference model instead of PI behavior
(only possible with 840D)
•
Setting the filter time to zero and setting the feedforward control factor to a value less
than 100%
•
Sacrificing the feedforward control and bringing the machine to a very high position
controller gain using dynamic stiffness control.
This measure requires a stiff machine.
With SW 5 and higher, a second, improved balancing filter is therefore available.
The existing filter is still installed and is active with the same function when transferring
existing archives (e.g., in the case of upgrades).
Advantages
The new balancing filter provides the following improvements:
•
An axis with feedforward control has a considerably lower inclination to undershoots
when positioning.
•
Achieves a higher accuracy at bent contours (can be measured, e.g., using the circularity
test) and can be set more easily.
•
A part of the setting is carried out by the control system automatically.
Summary of Contents for SINUMERIK 840D sl
Page 282: ...Index Basic logic functions Acceleration B2 64 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...
Page 388: ...Basic logic functions Travel to fixed stop F1 Function Manual 11 2006 6FC5397 0BP10 2BA0 52 ...
Page 962: ...Index Basic logic functions Emergency Stop N2 20 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...
Page 1704: ...Constraints Basic logic functions Spindles S1 94 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...
Page 1716: ...Index Basic logic functions Spindles S1 106 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...
Page 1996: ...Index Basic logic functions Tool Offset W1 208 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...
Page 2150: ...Table of contents Basic logic functions Appendix 4 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...
Page 2184: ...Glossary Basic logic functions Appendix 38 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...
