July 2013 7.7 Special functions 1101
7.7.5 TRC – Torque Ripple Compensation
General
information
Certain motors with permanent magnets (linear, torque and some
synchronous motors) have an increased, position-dependent variation of the
motor torque (not QSY motors from HEIDENHAIN). This can be the result of
two things:
During idle running, the cogging torque due to attractive forces of the
permanent magnets
When under load, the torque ripple from higher harmonics, resulting from
the opposing electromotive forces (generator effect)
In practice, both causes always occur together, i.e. the torque of the motor is
subject to periodic oscillations. This can have a negative effect on the
controllability of the motor, which can result in a greater following error, and
under circumstances, lower surface quality of the workpiece.
To compensate for the cogging torque, a compensation current ascertained
specifically for each motor can now be added.
Activating TRC TRC can only be activated via a special compensation file. The settings in this
file can only be made with the TNCopt commissioning software from
HEIDENHAIN (as of version 2.3). Please refer to the TNCopt documentation.
The compensation current is determined with a special method for
measurement, and the parameters for calculating this compensation are
stored in a compensation file on the control. The iTNC 530 then takes these
parameters into account when calculating the controller parameters.
Directory: PLC:\MP\TRC
File name: xx_<Motor_name>.TRC or new xx_<Motor_name>.CMP
• xx: Index of the axis (e.g. 00 = 1st axis, X axis)
• <Motor_name>: Name of the motor from the motor table (max. 29
characters)
• .CMP (old .TRC): File extension for "Torque Ripple Compensation"
TRC
Power stage
Speed control
Position
controller
Acceleration
feedforward
Nominal
position
Current
controller
Actual current
Actual position
Actual speed
Motor
Machine
slide
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