上海维宏电子科技股份有限公司
Weihong Electronic Technology Co., Ltd.
Specialized, Concentrated, Focused - 61 -
The popular explanation is: because the slider is generally fixed on the screw whose outer wire and
the inner wire on the outer wire cannot be completely matched, backlash compensation compensates
the clearance between the screw of last direction that the slider needs to finish after reversing its moving
direction.
Measuring Method
Backlash can be measured by a specialized gauge. Firstly, fix the instrument nearby the spindle.
Secondly, ma
ke the watch hand at the zero point position. Thirdly, manually move ―a‖ centimillimeter,
then move ―a‖ centimillimeter back, and then see the actual moving distance of watch hand: ―b‖
centimillimeter. Therefore, the backlash is measured, namely (a-b) centimillimeter.
Compensation Method
If one axis moves from positive to negative, ―+Q‖ pulse will be output before reversal; conversely,
from negative to positive, ―-Q‖ pulse will be output before reversal (Q is backlash, preset by program).
Screw Error Compensation File
Actually the system has already combined the above two errors for treatment.
The name of screw error compensation file is axeserr.dat, which can be copied to a U disk via the
―Outport‖ function in the system. Modification to the data in the screw error compensation file will
become valid after the software is restarted.
The file format is:
1) Firstly specify length unit, the length unit currently supported is mm and the style of writing is: unit =
mm
2) Then specify the error sequence of each axis. To work properly, the contents in this sequence must
be arranged in the ascending order of nominal mechanical coordinate value.
See the following for the format of a bilateral compensation file:
[<Axis Name>]
<Nominal Mechanical Coordinate>, <Forward Error>, <Backward Error>
<Nominal Mechanical Coordinate>, <Forward Error>, <Backward Error>
<Nominal Mechanical Coordinate>, <Forward Error>, <Backward Error>
The format of a unilateral compensation file is as follows:
[<Axis Name>]
<Nominal Mechanical Coordinate>, <Unilateral Error>, <Backlash>
<Nominal Mechanical Coordinate>, <Unilateral Error>, <Backlash>
<Nominal Mechanical Coordinate>, <Unilateral Error>, <Backlash>
Among them, <Axis Name> is X, Y, Z… (Case-insensitive)
Nominal mechanical value: it is the mechanical coordinate with sign corresponding to reference
point, which is calculated by given pitch and pulse equivalent (i.e. the length calculated based on
nominal pitch, not actual physical one), arranged in ascending order. Nominal mechanical
coordinate must be within the stroke range, or the compensation is invalid.
Every nominal mechanical coordinate does not need evenly spaced, with no limits to the record
density and points.
Backward error: the error generated by the motion towards decreasing direction of coordinate value.
Forward error: the error generated by the motion towards growing direction of coordinate value.
