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TR-Electronic GmbH 2007, All Rights Reserved
Printed in the Federal Republic of Germany
Page 218 of 260
TR - EMO - BA - DGB - 0013 - 00
05/16/2007
Subindex A: Reciprocal forward gain of the position control
Data
type
UNSIGNED32
Attribute
rw
Default
127432
Min
0
Max
2
32
-1
PDO
mapping
Yes
Description
This is the reciprocal (inverse value) gain or damping of the
open control loop of the position control and does not have
any unit. The feedback amplifications of the position
controller are multiplied by this value, so that the switch-off
frequency of the closed control loop corresponds to the
frequency settings fp and fd. This value is called rKs and is
calculated as follows:
rKs = Thetai/MN * iN/iM * 2Pi/Tc²
Is dependent on:
Thetai
Mass inertia of the rotor and the load in kgm²
MN
Rated motor torque in Nm or kgm
2
/s
2
iN
Rated motor current in mA (sine peak)
iM
Current stator current measuring range in mA
Tc = 1/fc
Cycle time of current controller in seconds
Arithmetic example of a brushless 300W DC motor without
load:
Thetai =
510*10
-7
kgm
MN
= 0.63 Nm
iN (effective) = 7600 mA
iN (peak)
= 2
0.5
* 7600 mA = 10748 mA
iM
= 24229 mA
Tc
= 1/10000 s
rKs =
22563
When the load increases, the mass inertia of the load is
added to the mass inertia of the rotor. In this way, the
damping of the open control loop also increases. If this
setting has been correctly performed, the increasing gains of
the position control will retain the necessary reaction times of
the closed control loop. If the gain is too high, the drive will
vibrate strongly. If the gain is too low, the drive will react
slowly and weakly and start to vibrate.