Operation: Localization

• Default available maps:

  • ETH_large_loop/TTIC_large_loop

Fig. 36 ETH_large_loop

Entity Definition

Entity	Description	Num Required	Configuration
Duckies	Rubber ducks, as pedestrians in the city/autolab	10	Color: Yellow
Autobots	The Duckiebots with top plate and Apriltags. Where the AIDO submissions will be installed and run.	3	DB22
Watchtowers	Cameras in the autolab that continue to recognize Apriltags (on the ground and Duckiebots).	6/7	WT19B
Duckietown	The robot that collects the transforms published from all other robots.	1	DT20

Operation instructions

In order to operate your autolab you need to set it up according to the following instructions:

1. Install docker-compose for the desktop machine: https://docs.docker.com/compose/install/

2. Make sure you are using a profile with the ente distribution by running :

   dts profile list
   

3. Update the commands:

   dts update
   

4. On the local machine, for ALL robots (Autobot, Watchtower, Duckietown):

   dts duckiebot update [HOSTNAME]
   

5. On robots, based on the robot type, create the following configs:

   • For ALL robots (Autobot, Watchtower, Duckietown): Replace [MAP_NAME] with the map name for this Autolab, e.g. ETH_large_loop or TTIC_large_loop:

     echo [MAP_NAME] > /data/config/autolab/map_name
     

   Attention

   Autobot only!

   • Replace [TAG_ID] with the AprilTag ID (just the number) on top of that Autobot:

     echo [TAG_ID] > /data/config/autolab/tag_id
     

6. On Watchtowers only, make sure that the dt-core container is running. You can do so by running this on your desktop/laptop:

   dts stack up -H [HOSTNAME] core -d
   

   Tip

   Make sure the AprilTag detector is spinning and you get detection messages in rostopic hz.

7. On the local machine, for ALL robots (Autobot, Watchtower, Duckietown), we need the Autolab layer running as well. You can do so by running this on your desktop/laptop:

   dts stack up -H [HOSTNAME] autolab -d
   

   Note

   This guide was written for the map ETH_large_loop. Replace it with your map name every time you find it in a command.

8. Check if you get data by cloning the repo https://github.com/duckietown/dt-autolab-localization and running the following command from its root:

   dts devel build -f
   dts devel run -L test-tf -- --hostname ETHlargeloop
   

   Attention

   The separator -- is not a typo; the hostname is the map name without underscores, so ETHlargeloop instead of ETH_large_loop. The map name is case sensitive.

   You should see an output like this:

   watchtower03/camera_optical_frame tag/326
   watchtower03/camera_optical_frame tag/307
   watchtower03/camera_optical_frame tag/326
   watchtower02/camera_optical_frame tag/308
   watchtower02/camera_optical_frame tag/322
   

   Make sure you get detections from all the watchtowers. Every 10s, the autobots will publish the transform between their footprint and the AprilTag on top of them:

   watchtower04/camera_opt
   
   

Another way of looking at this data is by running the following command (from the root of the same repository):

dts devel run -f -X -L single-experiment -- --hostname ETHlargeloop

This should wait 12 seconds for the observations to come in and put everything in a pose-graph that will be optimized and rendered. You should see something like this appear:

Integrate Odometry data (wheel encoders)

In order to integrate encoder data into the localization system, you need an extra container that takes the odometry data from the robot and feeds it into the localization system.

Note

You need to run this on every Autobot.

You can run the odometry integration with the command:

dts stack up -H [HOSTNAME] encoder -d

You can test that the data is correctly received by the localization system by running the test-tf application as done above. You should see something like the following, indicating that a transformation between the reference frame footprint of the robot at different timestamps is received:

autobot01/footprint autobot01/footprint
autobot01/footprint autobot01/footprint
autobot01/footprint autobot01/footprint