Adaptation of parameters
Acceleration and braking phases generate a variation which the speed control has
to balance out. With speed pre-control the necessary acceleration or braking
moment determined from the change in speed over time is applied to the output of
the speed controller.
If the travel range is not limited, it is advisable to optimize the speed controller by
means of step responses. In this, the motor model must be adapted precisely to the
individual motor. In the standard motor data set, the speed controller is preset for a
moderately stiff mechanical system. The speed controller may need to be adjusted to
the moment of inertia and the rigidity of the mechanism.
All parameters take effect online. The scaling parameter P 322[0] - CON_SCON_
KpScale is transferred in defined real time (according to the speed controller
sampling time).
The following steps are needed to set the speed control loop depending on the
application:
No.
Action
1
Adapt the speed controller gain to the existing external mass inertia. For
this, either the known moment of inertia from the motor data can be used
directly or the automatic mass inertia definition function in the Motor
Identification subject area can be used.
2
If the system's moment of inertia is defined manually, it must be reduced
to the motor.
MOOG
ID No.: CB40859-001 Date: 11/2020
MSD Servo Drive - Device Help
132
7 Control
Image 7.21: Relevant variables
J
M
Moment of inertia of motor
J
red
Reduced moment of inertia of system
i
Gear transmission ratio factor
J
2
Reduced moment of inertia
Legend for “Relevant variables”
ID
Index Name
Unit
Description
2695
CON_SCON_ScaleTF
Scaling filter time constant
2695
0
ScaleMaxSpeedFil
ms
Speed scaling filter time constant
2695
1
ScaleMaxTorqueFil
ms
Torque scaling filter time constant
320
0
CON_SCON_Kp
Nm/rpm Speed control gain
321
0
CON_SCON_Tn
ms
Speed control integration time constant
322
0
CON_SCON_KpScale
%
Speed control gain scaling factor
351
0
CON_SCALC_TF
ms
Speed calculation filter time constant, speed
control
371
0
CON_IP_RefTF
ms
Speed reference filter time constant (SCON
mode)
Table 7.12: “Speed controller” parameter
