(IVALab-tailored) ROS stack for interfacing with Robotis Dynamixel line of servo motors. This package is compatible with Python 2 and Python 3.
Add the package to your catkin workspace and build it.
# where ~/catkin_ws is your catkin workspace
cd ~/catkin_ws/src
git clone https://github.com/ivaROS/ivaDynamixel.git
cd ..
catkin buildThen include it in your package:
<run_depend>dynamixel_controllers</run_depend>See the dynamixel_tutorials package for examples on how to use the package.
We've provided a few docker containers to test library package functionality across a few versions of ROS i.e., kinetic, melodic, and noetic.
The purpose is to validate behavior of the module in both Python 2 and 3.
Containers take advantage of containerd, which uses Linux namespaces and control groups to run isolated images on the host kernel.
We mount /dev/ttyUSB0 onto the container, and validate that we can communicate with dynamixel motors from each ROS distribution.
Ensure your user is part of the dialout and docker groups.
We can build all container images:
docker compose buildThis may take some time, since this will pull down the base images for each of the images. Instead, you can specify a single container to build and run:
docker compose build kinetic
# script to verify information from motors
docker compose run --rm kinetic python src/ivaDynamixel/dynamixel_driver/scripts/info_dump.py 1 2 3
# to start the controller manager node
docker compose run --rm kinetic roslaunch dynamixel_tutorials controller_manager.launchWe can run any arbitrary script or launch file using the docker images.
If you run into any issues, make sure that there are no other programs actively communicating on the serial device on /dev/ttyUSB0.
Note that workspace is set under /app and the source for the repository under /app/src/ivaDynamixel.
The containers run using the host ip stack, so all ROS nodes will be available under rostopic or rosservice.
As an example, here is motor information run from kinetic on python 2, melodic on python 2, and noetic on python 3:
$ docker compose run --rm noetic python src/ivaDynamixel/dynamixel_driver/scripts/info_dump.py 1
Pinging motors:
1 ... done
Motor 1 is connected:
Freespin: False
Model ------------------- EX-106+ (firmware version: 28)
Min Angle --------------- 0
Max Angle --------------- 4095
Current Position -------- 798
Current Speed ----------- 0
Current Temperature ----- 37°C
Current Voltage --------- 8.1v
Current Load ------------ 0
Moving ------------------ False
$ docker compose run --rm melodic python src/ivaDynamixel/dynamixel_driver/scripts/info_dump.py 1
Pinging motors:
1 ... done
Motor 1 is connected:
Freespin: False
Model ------------------- EX-106+ (firmware version: 28)
Min Angle --------------- 0
Max Angle --------------- 4095
Current Position -------- 798
Current Speed ----------- 0
Current Temperature ----- 37\u00B0C
Current Voltage --------- 8.1v
Current Load ------------ 0
Moving ------------------ False
$ docker compose run --rm kinetic python src/ivaDynamixel/dynamixel_driver/scripts/info_dump.py 1
Pinging motors:
1 ... done
Motor 1 is connected:
Freespin: False
Model ------------------- EX-106+ (firmware version: 28)
Min Angle --------------- 0
Max Angle --------------- 4095
Current Position -------- 798
Current Speed ----------- 0
Current Temperature ----- 37\u00B0C
Current Voltage --------- 8.1v
Current Load ------------ 0
Moving ------------------ FalseTesting on melodic is tricky, since this is the first version of ROS that supported python 2 and 3, via ROS_PYTHON_VERSION.
At time of writing, we can simplify assumptions that most code and modules from this point is written for ROS noetic (or ROS 2), and thus sets ROS_PYTHON_VERSION=3.
We also test the behavior of the controller manager and spawner on python 2 vs python 3. The main difference is a change in import mechanism, but there is refactoring of the code too.
We will run controller_manager.launch and controller_spawner.launch from the dynamixel_tutorials package.
These need to get run in separate terminals in order to verify behavior.
Via kinetic:
docker compose run --rm kinetic roslaunch dynamixel_tutorials controller_manager.launch
docker compose run --rm kinetic roslaunch dynamixel_tutorials controller_spawner.launch
# from the dynamixel manager
process[dynamixel_manager-2]: started with pid [67]
[INFO] [1676480719.748477]: pan_tilt_port: Pinging motor IDs 1 through 25...
[INFO] [1676480722.229833]: pan_tilt_port: Found 9 motors - 1 MX-106 [2], 3 EX-106+ [1, 3, 4], 2 AX-12 [8, 9], 3 MX-28 [5, 6, 7], initialization complete.
[INFO] [1676480727.857555]: JointPositionController::JointPositionController() - Motor 5 bias set to 0.0000
[INFO] [1676480727.903481]: JointPositionController::JointPositionController() - Motor 6 bias set to 0.0000
# from the dynamixel spawner
process[dynamixel_controller_spawner-1]: started with pid [39]
[INFO] [1676480727.815928]: pan_tilt_port controller_spawner: waiting for controller_manager dxl_manager to startup in global namespace...
[INFO] [1676480727.820646]: pan_tilt_port controller_spawner: All services are up, spawning controllers...
[INFO] [1676480727.873546]: Controller pan_controller successfully started.
[INFO] [1676480727.916967]: Controller tilt_controller successfully started.Via noetic:
docker compose run --rm noetic roslaunch dynamixel_tutorials controller_manager.launch
docker compose run --rm noetic roslaunch dynamixel_tutorials controller_spawner.launch
# from the dynamixel manager
process[dynamixel_manager-2]: started with pid [49]
[INFO] [1676480834.207882]: pan_tilt_port: Pinging motor IDs 1 through 25...
[INFO] [1676480836.688936]: pan_tilt_port: Found 9 motors - 3 EX-106+ [1, 3, 4], 1 MX-106 [2], 3 MX-28 [5, 6, 7], 2 AX-12 [8, 9], initialization complete.
[INFO] [1676480841.728839]: JointPositionController::JointPositionController() - Motor 5 bias set to 0.0000
[INFO] [1676480841.763914]: JointPositionController::JointPositionController() - Motor 6 bias set to 0.0000
# from the dynamixel spawner
process[dynamixel_controller_spawner-1]: started with pid [32]
[INFO] [1676480841.695405]: pan_tilt_port controller_spawner: waiting for controller_manager dxl_manager to startup in global namespace...
[INFO] [1676480841.704013]: pan_tilt_port controller_spawner: All services are up, spawning controllers...
[INFO] [1676480841.739664]: Controller pan_controller successfully started.
[INFO] [1676480841.775393]: Controller tilt_controller successfully started.
[dynamixel_controller_spawner-1] process has finished cleanly