
4.SERVO FUNCTION DETAILS B-65270EN/05
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4.6.7 Two-stage Backlash Acceleration Function
(1) Overview
When the machine reverses the direction of feed, two types of delay
are likely to occur; one type due to friction in the motor and the other
due to friction in the machine.
The two-stage backlash acceleration function compensates for two
types of delays separately, thus enabling two-stage compensation.
First stage: The friction torque is canceled when
the motor reverses.
Second stage: The friction torque in the machine is
canceled.
Furthermore, optimum compensation can be performed at all times for
first stage against changing speed and load.
The two-stage backlash acceleration function performs compensation
as shown below:
Start
End
Time
The first stage compensation value is determined automatically.
Specify the parameter to determine how much of the estimated
friction is to be reversed.
First stage acceleration coefficient (normally set to 100%)
Second stage acceleration amount
(if this is 0, second stage does not
occur.)
Second stage
acceleration offset
(Normally, 0 is set.)
Second stage start and end parameters (detection unit)
The start point of second stage is specified as a distance relative to the
start of first stage.
The end point is determined automatically. Normally, if the setting is
positive, the end point is set at a distance two times greater than the
start point distance. If the setting is negative, the end point is set at a
distance three times greater than the start point distance. An arbitrary
end point can also be set by setting the end scale factor parameter.
Fig. 4.6.7 (a) Backlash acceleration under control of the two-stage
backlash acceleration function
(2) Series and editions of applicable servo software
Series 9096/A(01) and subsequent editions
Series 90B0/A(01) and subsequent editions
(specifying a direction-specific second stage acceleration amount and
a limit value)
Series 90B0/J(10) and subsequent editions
Series 90B6/A(01) and subsequent editions
Series 90B5/A(01) and subsequent editions
Two-stage
compensation