Tool Point Calibration

Provides a library and simple command line utility for doing 3 DOF (X, Y, Z) calibration of a robot's tool through the "touch point" method wherein the user jogs the robot to several poses where the tool to be calibrated touches the same point from different orientations.

Installation

The core tcp calibration library only requires the non-linear optimization solver Ceres to build. See this link for details on installation.

The console calibration utility uses ROS' TF libraries.

Use

To use:

1. Start up your robots driver as normal. A node like robot_state_publisher should be publishing TF frames of your robot.

2. Identify a base frame, either the base frame of the robot or the origin of the scene. This will be used for TF lookups, and the touch point will be reported in this frame.

3. Identify a tool0 frame. This is the frame from which you wish to calibrate a TCP. This will typically be the flange of the robot tool0.

4. Run the calibration node:

roslaunch tool_point_calibration console_calibration.launch base_frame:=YOUR_BASE_FRAME tool0_frame:=YOUR_TOOL0_FRAME num_samples:=NUMBER_OF_TOUCH_POINTS

       By default base frame is "base_frame", tool0_frame is "tool0", and num_samples is "4". I recommend you use at least 4 samples.

5. Jog the robot so that the tool you wish to calibrate is touching a known point in the world, such as the tip of a nail or the corner of a work-piece. When your're happy, press enter in the console window from which you ran the tcp calibration routine. You should see a 4x4 matrix print out.

   If you want to jog the robot using KUKA pendant in T1 mode, you can record the joint positions or the flange pose at each touch point and use those in ROS by running the move_robot.py script in the scripts folder. After rviz is launched and the tool_point_calibration program is running on a terminal, enter either the pose goal or joint goal of the touch point in the move_robot.py script and run the script to move the robot using moveit Python interface, and once the robot has moved to the target, press enter on the calibration terminal to record the point.

6. Repeat step 5 at least three more times. Each time approach the fixed point in the world from a different orientation. If you wish to abort early, control-C the node.

7. When you've captured all of the required points, the calibration will be automatically run and the output displayed to the screen.