Calibration file in emulator

Technical Questions
1

Hi,
I’m using the UR emulator and I want to access the calibration.conf . I think it is located in the /root/ folder is that right?
.However I cannot access it because permision are denied. Then I try su and use easybot as password but it returns authentication failure. Anyone know which is the correct password??

Thx

1 Like
2

Hi,

The calibration.conf file does not normally exist in URsim. You can copy one from a real robot though and it gets placed in the folder /home/ur/ursim-current/.urcontrol

To get to a Linux command prompt within the simulator environment type CTRL-ALT-T and this will get you to a terminal window where you can browse the filesystem and see the directory structure I point out.

3

Hi following this topic:
Which are the units in the calibration.conf file. Because I see that in the urcontrol.conf.Ur10 the denabit hatemberrs are in meters and radians.

However taking a look at the my calibration file which has these values

delta_theta = [ -9.40498298408416866e-06, 0.27068412154354593, -0.314903939784922426, 0.0442527515792477608, 9.34172007197231709e-06, 5.93755160400425455e-05]
delta_a = [ 4.68164294735672648e-05, 0.0220582008711670552, 0.00158057850161708036, -0.00035922185146348458, 0.000281769745099834986, 0]
delta_d = [ 0.000316664403174682363, 91.8991379508659634, -90.4485183223671356, -1.45123705292539418, -0.000375134660503345652, -0.000216232948727732022]
delta_alpha = [ 0.00031730707235522182, 0.0017812786528813092, -0.0174204031901766219, -0.00145566498545623979, -8.42411731953873755e-05, 0]

is imposible that delta_d is in m since it has values around 90, an also delta_theta in radians it seems to me that has very large values 0.3 radians is like 20º which I think is too much. So I understand the for delta_d and delta_a units are mm and for delta_alpha and delta_theta are degrees. Is that correct?

4

Hi Mojer,

The units for the calibration config are in m and radian. The first time I saw the values, they didn’t make any sense to me because they seemed too large. I used this procedure to verify the units for the calibration config (I am using UR5)

  1. I got the DH parameters of the UR5 from UR website.
  2. I coded the forward kinematic of the robot using those DH parameters to find the location of the J6 with respect to the base.
  3. I noticed there is a discrepancy between the values of my code and the values I was ready from the UR controller, and when I added the values of the calibration.conf to its corresponding DH parameters, I got exactly the same values as the controller.

This procedure proved me that the units for the calibration.conf are meter and radians, still I have no idea how UR extracted them like this!

I hope it helps.