Difference between revisions of "MC-Basic:axis.PositionBacklash"

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{{Languages|MC-Basic:axis.PositionBacklash}}
 
{{MC-Basic
 
{{MC-Basic
 
|SHORT FORM=  
 
|SHORT FORM=  
 
None
 
None
 
|SYNTAX=
 
|SYNTAX=
<axis>.PositionBacklash = double
+
<''axis''>.PositionBacklash = <double>
 
|AVAILABILITY=  
 
|AVAILABILITY=  
 
4.5.33 and later
 
4.5.33 and later
 +
 
|DESCRIPTION=
 
|DESCRIPTION=
Adds a position backlash value to the pcmd value. The value will be added in positive direction of the movement (<axis>.vcmd > 0) while in opposite direction the value multiplied by -1 will be used. In stand-still situation (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.
 
 
Changes between positive and negative applied backlash value will be smoothen by a simple alpha-filter : [[Axystems:MC-Basic:PositionBacklashAlpha]].
 
 
 
According to:
 
  
P = P*Alpha + sign*PositionBacklash*(1-Alpha)
+
Differences between positive and negative applied backlash values will be smoothed by a simple alpha-filter: [[MC-Basic:axis.PositionBacklashAlpha|'''PositionBacklashAlpha''']].
  
where sign = -1 on vcmd <0 else equals 1.
 
  
{{Note/Important| The backlash position value is not compensated in the position feedback. Therefore applying position backlash to a certain non-zero value will result in having the same opposite value in PE (position error) it will look like PE is never closed.}}
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[[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/Warning| Be cautious. The feature is not tested well enough.}}
 
  
 
|TYPE=  
 
|TYPE=  
double
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Double
 
|RANGE=
 
|RANGE=
 
MIND ... MAXD
 
MIND ... MAXD
 
|UNITS=
 
|UNITS=
position user units
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Position user units
 
|DEFAULT=
 
|DEFAULT=
 
0
 
0
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Task, Terminal
 
Task, Terminal
 
|LIMITATIONS=
 
|LIMITATIONS=
Modal-Only
+
Modal only
 
|EXAMPLE=
 
|EXAMPLE=
 
a1.PositionBacklash = 0.5
 
a1.PositionBacklash = 0.5
 
|SEE ALSO=
 
|SEE ALSO=
[[Axystems:MC-Basic:PositionBacklashAlpha]]
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* [[MC-Basic:axis.PositionBacklashAlpha|PositionBacklashAlpha]]
 
}}
 
}}

Latest revision as of 03:37, 20 April 2017

Language: English  • 中文(简体)‎

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 smoothed by a simple alpha-filter: PositionBacklashAlpha.


Picture showing different values of backlash compensation in different movement directions. Note the influence of PositionBacklashAlpha factor (0.9, 0.95, 0.99)
IMPORTANT.svgIMPORTANT
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

See Also