Difference between revisions of "MC-Basic:axis.PositionBacklash"
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Adds a position backlash value to the PCMD value. The value will be added to the positive direction of the movement (<''axis''>.VCMD > 0), while in opposite direction the value multiplied by -1 is used. At a standstill (VCMD = 0), the previous value of the backlash is used. | Adds a position backlash value to the PCMD value. The value will be added to the positive direction of the movement (<''axis''>.VCMD > 0), while in opposite direction the value multiplied by -1 is used. At a standstill (VCMD = 0), the previous value of the backlash is used. | ||
| − | Differences between positive and negative applied backlash values will be smoothened by a simple alpha-filter: [[MC-Basic:axis.PositionBacklashAlpha]]. | + | Differences between positive and negative applied backlash values will be smoothened by a simple alpha-filter: [[MC-Basic:axis.PositionBacklashAlpha|'''PositionBacklashAlpha''']]. |
According to: | According to: | ||
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where <''sign''> = -1 on VCMD <0 else equals 1. | where <''sign''> = -1 on VCMD <0 else equals 1. | ||
| − | [[File:Backlash.jpg|frame|Picture showing different values of backlash compensation in different movement directions. Note the influence of PositionBacklashAlpha factor (0.9, 0.95, 0.99)| | + | [[File:Backlash.jpg|frame|Picture showing different values of backlash compensation in different movement directions. Note the influence of PositionBacklashAlpha factor (0.9, 0.95, 0.99)|700px]] |
{{Note/Important| The backlash position value is not compensated in the position feedback. Therefore, applying position backlash to a non-zero value will result the same opposite value in the position error (PE). It will look like PE is never closed.}} | {{Note/Important| The backlash position value is not compensated in the position feedback. Therefore, applying position backlash to a non-zero value will result the same opposite value in the position error (PE). It will look like PE is never closed.}} | ||
Revision as of 12:31, 15 September 2014
Adds a position backlash value to the PCMD value. The value will be added to the positive direction of the movement (<axis>.VCMD > 0), while in opposite direction the value multiplied by -1 is used. At a standstill (VCMD = 0), the previous value of the backlash is used.
Differences between positive and negative applied backlash values will be smoothened by a simple alpha-filter: PositionBacklashAlpha.
According to:
P = P × Alpha + <sign> × PositionBacklash × (1-Alpha)
where <sign> = -1 on VCMD <0 else equals 1.
Picture showing different values of backlash compensation in different movement directions. Note the influence of PositionBacklashAlpha factor (0.9, 0.95, 0.99)
 | IMPORTANT |
| The backlash position value is not compensated in the position feedback. Therefore, applying position backlash to a non-zero value will result the same opposite value in the position error (PE). It will look like PE is never closed. |
Short form
None
Syntax
<axis>.PositionBacklash = <double>
Availability
4.5.33 and later
Type
Double
Range
MIND ... MAXD
Units
Position user units
Default
0
Scope
Task, Terminal
Limitations
Modal only
Examples
a1.PositionBacklash = 0.5