What is meaning of doing calibration of a industrail robot?

The control program has a model that it thinks the robot conforms to.  =
If you change a part, that might change the model.  E.g., if you put in =
a new joint, the resolvers for that joint may have a different reading =
for the zero-angle position, so you must update your model.  Some =
calibration also takes out measurement errors in the model, by putting =
the robot in a known position, and massaging the model until it agrees.

Mike Ross

  > Hi,guys,
  >
  > Some times I heard that if some parts of a industrial robot changed,
  > it need to do some calibrating?
  > And what's the meaning? Why and how to do it?
  >
  > Thanks.

  The control program has a model that it thinks the robot conforms to.  =
If you change a part, that might change the model.  E.g., if you put in =
a new joint, the resolvers for that joint may have a different reading =
for the zero-angle position, so you must update your model.  Some =
calibration also takes out measurement errors in the model, by putting =
the robot in a known position, and massaging the model until it agrees.

  Mike Ross



  No two parts are created equal. Whenever you change a part, crash the =
machine, or sometimes time alone, will cause the machine to lose it's =
bearings. Then you recalibrate to maintain exact repeatability. We have  =
8 axis CNC's that require recalibration on almost a daily basis due to =
the inherent vibrations that are caused by their normal operation. In a =
nutshell your just pointing out home to the computer.

  None sense , thats make work , and

 uncompetitive , no one would buy such

  a "costly" ROBOT !

   ROBOTs have many levels of precision ,

 the fine level is so clever and adaptive , it

 corrects for tool wear as CNC do ..

 Trade Unionists !

Then explain why the government sets industry standards for calibrations if
machines can be so perfect?  (Why pay for yearly / bi-yearly
certifications?) And then why do the machine manufacturers include
calibration tools with the equipment when they sell them to you? Do you
trust the scale you purchase your meat from? I have ISEA robots that are
self homing and self recalibrating, but they still require a confirmation
setup from time to time, as well as a certification from a licensed
technician on a timely basis, and the technician uses special calibration
tools to know how much deviation must be adjusted in the operating parameter
to maintain repeatability.

On 4ÔC24ÈD5, ÏC2ÎE73ÊB124·D6, "Mike Ross" <mike.l.r...@na=

 joint, the resolvers for that joint may have a different reading for the z=
ero-angle position, so you must update your model.  Some calibration also t=
akes out measurement errors in the model, by putting the robot in a known p=
osition, and massaging the model until it agrees.

Thank you. Mike.

"By putting the robot in a known postion"?? does it mean that before
changing the part of the robot ,you must record the reference point
and save it as a point file,then move the robot to the point after
finishing changed. Then check the error and
calibrate it.
Right??

Thank you. Mike.

"By putting the robot in a known postion"?? does it mean that before
changing the part of the robot ,you must record the reference point
and save it as a point file,then move the robot to the point after
finishing changed. Then check the error and
calibrate it.
Right??


I guess that is one way.  Usually you're interested in the tool position
being right, so you use some pre-made and pre-measured jig to grab with the
robot's end-effector, thus placing it in a known (i.e. repeatable) position.

Mike Ross

On 4æ9C�5æ97¥, äB8�E5�883æ97¶07å88�, "Mike Ros=

It's very nice of you.Mike.


calibrating  industrial robot, don't it ?

ew joint, the resolvers for that joint may have a different reading for the=
 zero-angle position, so you must update your model.  Some calibration also=
 takes out measurement errors in the model, by putting the robot in a known=
 position, and massaging the model until it agrees.

I  have worked on industrial robots for quite some time. The
calibration, in general, means fixing the robots coordinate systems to
known setup.
In case of cartesian robot arms, for example, you have limit sensors
at each end of the travel lenght of each axis. Three axes are
supposedly mechanically perpendicular to eachother.

Well, the problem is, they never are. So if you want a half-millimeter-
precision positioning, you have to fix the coordinate system
transforms so that the mechaniocal irregularities ( a small angle
between the axes ) are taken into the account. Thats part of
calibration. You also want to make sure that +- directions of each
axis is correct, and the "zero point" of coordinates is reached
properly, this usually involves adjusting the limit sensors ( moving
them a little this or that way )

Once calibrated, the robot will know its position after each powerup
and homing procedure with a very high precision.
An uncalibrated robot might move irregularly, i.e. you give it a
command to move +10 mm in X direction, but it moves 9.5 in X and 0.2
in Y or somesuch.

hope that explains it.

-kert

On 4ÔC27ÈD5, ÉCFÎE73ÊB151·D6, "kert" <kaidok...@gmail.com=

 new joint, the resolvers for that joint may have a different reading for t=
he zero-angle position, so you must update your model.  Some calibration al=
so takes out measurement errors in the model, by putting the robot in a kno=
wn position, and massaging the model until it agrees.

Thank you very much for your detailed explaination about calibration.
kert.