We have a rotary axis set as axis 8, the Ac servo is mounted with a Gear reducer (gear reducer from a KR125 robot A3), with this settings $RAT_MOT_AX[8]={N185, D 1} when typed in 90 degree the actual rotary table output is below 90 degree, we are not sure which part of the gear ratio setting was wrong, need some help.
rotary axis Gear ration settings
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happytriger2000 -
March 14, 2013 at 8:40 AM -
Thread is Resolved
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$RAT_MOT_AX[8]={N185, D 1}What is the gearbox reduction ratio? You have it set for 185:1.
Is this a new installation or have you just changed the gearbox etc
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Hello Eusty,
We know the gear reducer & motor was taken off from a used KR125 robot A3 axis, before disassembly we checked the KR125 Robot's machine data which described N185, D1, that's how we know it.
We are using this gear reducer as an external rotary table.
here's a picture of what we are doing:
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Okay, that's the problem. On the KR125, the motor fed into a gearbox (actually, a harmonic drive) that was part of the A3 axis. So that $RAT_MOT_AX value is NOT going to be valid.
The KUKA servo settings need two different settings:
$RAT_MOT_ENC, which is the ratio of rotations between the drive shaft and the encoder/resolver. This is internal to the motor, and will match the settings for A3 on the robot this motor was removed from.
$RAT_MOT_AX, which is the ratio of the motor drive shaft to the rotation (or linear mm, for linear axes) of the axis the motor is turning. Since you appear to have a home-made axis, you will probably have to determine this value empirically. An inclinometer should be sufficient, in this case, unless you need really high precision. -
Okay, that's the problem. On the KR125, the motor fed into a gearbox (actually, a harmonic drive) that was part of the A3 axis. So that $RAT_MOT_AX value is NOT going to be valid.The KUKA servo settings need two different settings:
$RAT_MOT_ENC, which is the ratio of rotations between the drive shaft and the encoder/resolver. This is internal to the motor, and will match the settings for A3 on the robot this motor was removed from.
$RAT_MOT_AX, which is the ratio of the motor drive shaft to the rotation (or linear mm, for linear axes) of the axis the motor is turning. Since you appear to have a home-made axis, you will probably have to determine this value empirically. An inclinometer should be sufficient, in this case, unless you need really high precision.Could it possibly be a planetary drive?
Before going for the inclinometer, I'm sure there should be some spec info. can be found for the gear reducer, what's the manufacturer?
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copy all the settings from a kr125/3 axis into mada for your ext axis should be simple
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Not if he's using a different gearbox between the motor and the axis, which appears to be the case.
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He said the motor and gearbox was from a 125
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Happytrigger are you in the UK ?
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If you decide to go for a Christmass beer in London, i am available
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the system is in the uk or not
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If you decide to go for a Christmass beer in London, i am available
Very kind of you.
I will be doing some traveling across Europe with my family after Xmas.
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the system is in the uk or not
Person is in the Uk, Kuka system in Taiwan. -
OK to far to pop and see it then lol
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