Autotuning Of Position / Speed Controller; Ks Determination - Baumuller b maXX BM3000 Operating Manual

Description of the Software Modules and Parameters
4.4.8

Autotuning of position / speed controller

The "system gain" that is determined by the complete inertia torque of the drive, the mo-
tor-torque constant Kt and the magnetic flux are combined at the rated point in the Ks fac-
tor Z18.40–.
The actual value of the "gain" is calculated in the parameter ""Ks actual value" Z155.10–.
The inverse of the "Ks actual value" Z155.10–: (1/Ks), serves in the controller as a stan-
dardization constant between the acceleration value (speed controller output) and the
torque current set value. Therefore, ideally, the parameterization of the position/speed
controller is independent of the existing controlled system. The speed controller can be
parameterized with a symmetric optimum independent of the used motor and the existing
drive inertia torque.
The optimized values of the speed controller can not be used for all drives. For example,
a great load inertia could cause that the distortion in the torque current set value is ex-
ceeded by 10% of the motor nominal current, which was caused by the speed ripple (de-
pendent of the encoder type) and gained by a (1/Ks) which is too great. In this case the
encoder smoothing should be increased (to reduce the ripple) or a smoother setting of the
speed controller should be made. ProDrive offers a calculating tool for a smoother setting.
Automatic identification of controlled system
It is possible to carry out an automatic identification of the controlled system with the con-
troller. The values at the speed controller, the positioning controller Kv factor as well as
at the inertia torques and the Ks factor are determined. See
filter setting–

4.4.8.1 Ks Determination

The value of the factor Ks at the measuring point, Ks factor
or measured (also refer to
Ks calculation
The Ks factor
with
Ks factor
Flux
Kt
Kt factor
J
on page 714 for a detailed description.
ZThe factor Ks–
Z18.40–
can be calculated as follows:
180
---------- -
Ks factor =
Z18.40–
Parameter
100% (according to definition of the Ks factor Z18.40–)
nom
Kt = Kt factor, in Nm/A
Motor Kt in Nm/A
Torque of the drive in kg m
controller are shown in kg cm
on page 446).
o
Flux
------------------- - Kt
 nom 
----- -

100 J
2
in (degree/s )/A
Z107.44–
(Attention: Torque inertia parameters of the 
2
2
!)
Parameter manual b maXX BM3000
Document no.: 5.12001.07
4
ZAutomatic controller and
Z18.40–
can be calculated
207
of 820