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Not enough valid calibration points(use T-mac)

#1
I'm trying to calibrate a doosan robot. I used Leica laser tracker and T-mac Basic.
I ran the calibration program trying 40 and 80 points, but I received an error message(Not enough valid calibration points)

Can I get a solution?


Attached Files
.rdk   M1013_CALIB_environment_ver1.rdk (Size: 6.47 MB / Downloads: 27)
#2
The Doosan models available on our library need a minor modification so we can calibrate them. In short, we should transfer the rotation of the XY plane of the robot base from the Theta 1 parameter to the Base frame as shown in the attached image.
   

If you have this change and follow the calibration procedure you should not find the strange issues you have (the measurements were not considered valid). I just fixed this detail with your Doosan robot and recalculated the measurements. See the RDK project file attached.

The data collected looks great and the calibration is successful with this edit! See the RDK project file attached. The accuracy can be improved from a max position accuracy of 3.2 mm using the nominal kinematics to 0.185 mm using the accurate kinematics.
   

Small detail: Since the tool also changes we should open and close the measurements menu and accept the suggested update (updated tool pose).


Attached Files
.rdk   M1013_CALIB_environment_ver2-fixed.rdk (Size: 6.47 MB / Downloads: 31)
#3
Thank you for your support.

Feedback was a little late.
The calibration was successful as you said. But I found one problem.
As shown in the picture, the base has been rotated 180 degrees.

Does this have no effect on control?

As an additional question, I'm curious as to whether the DH parameters do not change after calibration.


Attached Files Thumbnail(s)
       
#4
Good point, we'll fix the base model.

When you calibrate the robot you'll obtain a new set of parameters. To take advantage of the full RoboDK calibration you should generate programs directly from RoboDK and you'll obtain the programs automatically filtered.
#5
When i enter same joint values before and after calibration, I confirmed that TCP changed.

My team leader has two questions.

First, He wants to know how the link parameter has changed.
Can we see the link parameter changed?

Sencondly, if we calibrate, will the robot model graphics in the simulation also change?
We also want to create scenarios in the simulation before applying scenarios to the real environment.
We think it is right to create a scenario with graphic changes reflected, but I am not sure if the robot model has changed after calibration.


Attached Files Thumbnail(s)
   
#6
You can see all the calibrated parameters by selecting on "Parameters from the robot panel, then, select More options.

The robot model does not change, however, the position of the TCP changes a bit. In general, robot calibration corrects about 1-5 mm (or 2.5 mm in this specific case). Therefore, you'll see the flange deflect slightly by this amount.
  




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