1.9 KiB
ur_calibration
Package for extracting the factory calibration from a UR robot and changing it to be used by ur_description to gain a correct URDF model.
Each UR robot is calibrated inside the factory giving exact forward and inverse kinematics. To also make use of this in ROS, you first have to extract the calibration information from the robot.
Though this step is not necessary, to control the robot using this driver, it is highly recommended to do so, as end effector positions might be off in the magnitude of centimeters.
Nodes
calibration_correction
This node extracts calibration information directly from a robot, calculates the URDF correction and saves it into a .yaml file.
With the parameters explained below calibration will be saved inside
<output_package_name>/<subfolder>/<robot_name>_calibration.yaml
Helper script
In the launch folder of the ur_calibration package is a helper script:
$ roslaunch ur_calibration calibration_correction.launch \
robot_ip:=<robot_ip> \
robot_name:=<robot_name> \
output_package_name:=ur_calibration \
subfolder_name:=etc
For the parameter <robot_ip> insert the ip on which the ROS pc can reach the robot. The <robot_name> is an arbitrary name you can give to the robot. It is recommended, to choose a unique name that can be easily matched to the physical robot.
As soon as you see the output
[ INFO] [1560953586.352160902]: Calibration correction done
you can exit the roslaunch by pressing CTRL+C.
Prerequisites for binary installation
In the example above, we use the ur_calibration package from this repository. This won't work, if you use a binary installation of this driver. In that case please create a new ROS package by going to your catkin_workspace's src folder and calling:
catkin_create_pkg my_calibrations
It is recommended to adapt the new package's package.xml with a meaningful description.