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Calibration

Modified 2020-03-04 by Timothy Scott

A Duckiebot set up according to Unit E-1 - Setup

A calibrated DBV2.

DBV2 follows the same calibration procedure as DB18 for the camera, as described in Unit C-13 - Calibration - Camera. The camera on DBV2 is placed at the exact same hight and orientation as DB18, so you can use the same calibration grid.

You must also calibrate the new sensors on DBV2.

Calibration overview

Modified 2020-03-04 by Timothy Scott

Unlike camera calibration, the sensor calibration on DBV2 is not yet packaged in an easy-to-run demo. Therefore, the procedure to run these calibrations is not intuitive. Every calibration will follow a similar process:

Step 1: Stop the duckiebot-interface-dbv2 container: Each sensor calibration reads directly from the sensor. If duckiebot-interface-dbv2 is also running, and also trying to read from the same sensor, there can be conflicts on the communication bus.

Step 2: Run a docker command: The docker commands given below create temporary containers for calibration. They use the following flags: - --privileged: Gives the container access to hardware and communication buses (I2C, GPIO, etc.) - -it: Starts the container interactively, because the calibration procedures need user input - -v /data:/data: Attaches the folder /data on the host raspberry pi to the location /data within the container. This is needed by all duckietown containers to store calibration files that persist between containers. - --network=host: This is used by all duckietown containers to allow them to communicate with the ROS master - --rm: Remove the container when done. Because calibration only needs to be done once for each sensor, it makes sense to clean up the containers when done.

Step 3: Give input on the command line: The calibration procedures require you to provide some data that you measure, to compare to the data the sensors measure and adjust accordingly.