52
Digital servo control
Integrated inverter
Position controllers, speed controllers, current controllers and
inverters are integrated in the MANUALplus 620. HEIDENHAIN
synchronous or asynchronous motors are connected to the
MANUALplus 620.
Axis feedback
control
The MANUALplus 620 can be operated with following error or
feedforward control.
Operation with
following error
The term “following error” denotes the distance between the
momentary nominal position and the actual position of the axis.
The velocity is calculated as follows:
v = velocity
k
v
= position loop gain
v = k
v
· s
a
s
a
= following error
Operation with
feedforward
control
Feedforward means that the speed and the acceleration are
adjusted to fit the machine. Together with the values calculated
from the following error, it forms the nominal value. This greatly
reduces the following error (to within a few µm).
Compensation of
torque ripples
The torque of synchronous, torque and linear motors is subject
to periodic oscillations, one cause of which can be permanent
magnets. The amplitude of this torque ripple depends on the
motor design, and under certain circumstances can have an
effect on the workpiece surface. After the axes have been
commissioned with the TNCopt software, the Torque Ripple
Compensation (TRC) of the CC 61xx or UEC 11x can be used to
compensate it.
Control loop cycle
times
The cycle time for path interpolation is defined as the time
interval during which interpolation points on the path are
calculated.
Double-speed
control loops
(option 49)
Double-speed control loops permit higher PWM frequencies as
well as shorter cycle times of the speed controller. This makes
improved current control for spindles possible, and also higher
control performance for linear and torque motors.
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