# ROS2 Control Framework **URL:** https://get-help.theconstruct.ai/c/course-support/ros2-control/69.md [Latest](https://get-help.theconstruct.ai/latest.md) · [Categories](https://get-help.theconstruct.ai/categories.md) · [Tags](https://get-help.theconstruct.ai/tags.md) --- ## [About the ROS2 Control Framework category](https://get-help.theconstruct.ai/t/about-the-ros2-control-framework-category/17434)
**Author:** [@bayodesegun](https://get-help.theconstruct.ai/u/bayodesegun)\ **Replies:** 0
--- ## [Is the onit() method, parameters read from .yaml file? or URDF?](https://get-help.theconstruct.ai/t/is-the-onit-method-parameters-read-from-yaml-file-or-urdf/42058)
**Author:** [@ik2060](https://get-help.theconstruct.ai/u/ik2060)\ **Replies:** 2\ **Last updated:** [August 11, 2026, 8:11am UTC](https://get-help.theconstruct.ai/t/is-the-onit-method-parameters-read-from-yaml-file-or-urdf/42058 "2026-08-11T08:11:34Z")
In the module 5.7, which explains the source code of the hardware implementation, it says " In the first line, the parent on\_init is called to process the parameters read from the .yaml configuration file. This is done … --- ## [Why initialize values with 'quiet\_NaN' in ros2\_control?](https://get-help.theconstruct.ai/t/why-initialize-values-with-quiet-nan-in-ros2-control/34734)
**Author:** [@jeroendm](https://get-help.theconstruct.ai/u/jeroendm)\ **Replies:** 1\ **Last updated:** [March 6, 2025, 12:31pm UTC](https://get-help.theconstruct.ai/t/why-initialize-values-with-quiet-nan-in-ros2-control/34734 "2025-03-06T12:31:38Z")
In controller and hardware interface implementations, variables are often initialized with quiet\_NaN. For example, in Unit 4 of the “ROS2\_Control Framework Course”, the command and state values are initialized in the on\_… --- ## [Unit 2 Exercise 2.7.1 - Joints are not responding --](https://get-help.theconstruct.ai/t/unit-2-exercise-2-7-1-joints-are-not-responding/34435)
**Author:** [@MohamedAliZouari](https://get-help.theconstruct.ai/u/MohamedAliZouari)\ **Replies:** 1\ **Last updated:** [January 20, 2025, 9:36am UTC](https://get-help.theconstruct.ai/t/unit-2-exercise-2-7-1-joints-are-not-responding/34435 "2025-01-20T09:36:31Z")
Hi guys. I have the same problem as this Could you please help me the code is good and the colcon build and source are correctly worked , the output is also works fine but after i deleted the old model and launch the … --- ## [Unit 6: unable to load the controller](https://get-help.theconstruct.ai/t/unit-6-unable-to-load-the-controller/34254)
**Author:** [@azurechen1203](https://get-help.theconstruct.ai/u/azurechen1203)\ **Replies:** 3\ **Last updated:** [January 7, 2025, 1:23pm UTC](https://get-help.theconstruct.ai/t/unit-6-unable-to-load-the-controller/34254 "2025-01-07T13:23:08Z")
Hi, I am currently working on exercise 6.2.1 in ROS2 Control Framework and have made some modifications to the description file (.xacro) and added a configuration file (.yaml). The launch file executes successfully, and… --- ## [Error of server for controllers not being reached](https://get-help.theconstruct.ai/t/error-of-server-for-controllers-not-being-reached/33471)
**Author:** [@Takudzwa](https://get-help.theconstruct.ai/u/Takudzwa)\ **Replies:** 5\ **Last updated:** [November 14, 2024, 9:33am UTC](https://get-help.theconstruct.ai/t/error-of-server-for-controllers-not-being-reached/33471 "2024-11-14T09:33:59Z")
I am working on the ROS 2 Control Framework course and on chapter 3, I am getting the error saying that “Could not contact service /controller\_manager/list\_controller\_types” in the image attached below. Kindly assist on … --- ## [Position\_trajectory\_controller is not explained in Unit 4](https://get-help.theconstruct.ai/t/position-trajectory-controller-is-not-explained-in-unit-4/32177)
**Author:** [@sunhongshuai](https://get-help.theconstruct.ai/u/sunhongshuai)\ **Replies:** 1\ **Last updated:** [September 11, 2024, 12:27pm UTC](https://get-help.theconstruct.ai/t/position-trajectory-controller-is-not-explained-in-unit-4/32177 "2024-09-11T12:27:29Z")
in controller\_configuration.yaml there is config position\_trajectory\_controller position\_trajectory\_controller: type: joint\_trajectory\_controller/JointTrajectoryController also in launch file, there is a node tr… --- ## [\[Bug\] \[Bug\] Unit7 - Loading controller](https://get-help.theconstruct.ai/t/bug-bug-unit7-loading-controller/30000)
**Author:** [@clusher](https://get-help.theconstruct.ai/u/clusher)\ **Replies:** 3\ **Last updated:** [April 23, 2024, 8:33am UTC](https://get-help.theconstruct.ai/t/bug-bug-unit7-loading-controller/30000 "2024-04-23T08:33:38Z")
This is an error report. Screenshot of the error Error details After following the Unit 7 without problems, the final steps ended up in the error in the image. Gazebo was launched, but when the robot is spawned, th… --- ## [\[Bug\] Unit 7: Custom Controller launch error](https://get-help.theconstruct.ai/t/bug-unit-7-custom-controller-launch-error/29176)
**Author:** [@Agarcia5612](https://get-help.theconstruct.ai/u/Agarcia5612)\ **Replies:** 8\ **Last updated:** [March 6, 2024, 4:04am UTC](https://get-help.theconstruct.ai/t/bug-unit-7-custom-controller-launch-error/29176 "2024-03-06T04:04:57Z")
This is an error report. Screenshot of the error Error details Hello, I wanted to ask for some advice for unit 7; I had issues with the final example with executing the command to not only spawn Unit 2 RRbot wit… --- ## [Unit2: What does source /home/simulations/ros2\_sims\_ws/install/setup.bash do?](https://get-help.theconstruct.ai/t/unit2-what-does-source-home-simulations-ros2-sims-ws-install-setup-bash-do/29196)
**Author:** [@jonas.haeberli](https://get-help.theconstruct.ai/u/jonas.haeberli)\ **Replies:** 3\ **Last updated:** [March 4, 2024, 1:50am UTC](https://get-help.theconstruct.ai/t/unit2-what-does-source-home-simulations-ros2-sims-ws-install-setup-bash-do/29196 "2024-03-04T01:50:59Z")
Hello, I’m trying to get my robotic arm to work in gazebo on my local machine. But it seems like there is an issue when I launch it. I think all my gazebo and urdf things are okay. I now saw that i get the same behaviour… --- ## [\[Bug\] Unit 6 Diffbot Error loading the controller](https://get-help.theconstruct.ai/t/bug-unit-6-diffbot-error-loading-the-controller/29109)
**Author:** [@Agarcia5612](https://get-help.theconstruct.ai/u/Agarcia5612)\ **Replies:** 3\ **Last updated:** [March 2, 2024, 7:32pm UTC](https://get-help.theconstruct.ai/t/bug-unit-6-diffbot-error-loading-the-controller/29109 "2024-03-02T19:32:43Z")
This is an error report. Screenshot of the error Error details Hello, I wanted to ask for advice for debugging this issue I had with the diff robot; I fixed one of the main issues which involved the missing xacro… --- ## [\[Bug\] Colcon Build error for the Dynamixel Workbench](https://get-help.theconstruct.ai/t/bug-colcon-build-error-for-the-dynamixel-workbench/29106)
**Author:** [@Agarcia5612](https://get-help.theconstruct.ai/u/Agarcia5612)\ **Replies:** 5\ **Last updated:** [February 28, 2024, 6:38am UTC](https://get-help.theconstruct.ai/t/bug-colcon-build-error-for-the-dynamixel-workbench/29106 "2024-02-28T06:38:50Z")
This is an error report. Screenshot of the error Error details Hello all, I was working in the ROS2 Control Framework course. Everything has worked so far. I ran into issues building the Unit 5 packages for the Dy… --- ## [Unit 4 lesson error](https://get-help.theconstruct.ai/t/unit-4-lesson-error/27776)
**Author:** [@endika](https://get-help.theconstruct.ai/u/endika)\ **Replies:** 2\ **Last updated:** [December 12, 2023, 10:49am UTC](https://get-help.theconstruct.ai/t/unit-4-lesson-error/27776 "2023-12-12T10:49:47Z")
Bon dia. I have this error in a 4 unit. I need help to solve. \[ros2\_control\_node-1\] what(): Failed to load library /home/user/ros2\_ws/install/my\_robot\_hardware\_interface/lib/libmy\_robot\_hardware\_interface.so. Make s… --- ## [Cannot build the dynamixel hardware interface in ros2\_control course](https://get-help.theconstruct.ai/t/cannot-build-the-dynamixel-hardware-interface-in-ros2-control-course/25749)
**Author:** [@pbnpama](https://get-help.theconstruct.ai/u/pbnpama)\ **Replies:** 3\ **Last updated:** [August 9, 2023, 8:21am UTC](https://get-help.theconstruct.ai/t/cannot-build-the-dynamixel-hardware-interface-in-ros2-control-course/25749 "2023-08-09T08:21:11Z")
I followed the ros2 control course and tried to use the dynamixel hardware interface in my own labtop and this error was come. I’m not familiar with C++ so If someone know what should I fix, please tell me. Basically, I … --- ## [Unit 5 - Exercise 5.22.1: Cannot build after setup all the exercises](https://get-help.theconstruct.ai/t/unit-5-exercise-5-22-1-cannot-build-after-setup-all-the-exercises/23841)
**Author:** [@PhongNguyen](https://get-help.theconstruct.ai/u/PhongNguyen)\ **Replies:** 4\ **Last updated:** [April 18, 2023, 8:19pm UTC](https://get-help.theconstruct.ai/t/unit-5-exercise-5-22-1-cannot-build-after-setup-all-the-exercises/23841 "2023-04-18T20:19:37Z")
I have gone through and set up all the Exercises as guidance: Here is my dynamixel\_hardware\_interface.cpp after all the exercises: #include \ #include \ #include \ #include \ #include \ **Author:** [@HusamArdah](https://get-help.theconstruct.ai/u/HusamArdah)\ **Replies:** 4\ **Last updated:** [April 18, 2023, 8:30am UTC](https://get-help.theconstruct.ai/t/unit-2-exercise-2-7-1-joints-are-not-responding/23586 "2023-04-18T08:30:29Z") When I launched the my\_robot.launch.py the first time when going through the exercise, I was able to modify joint1 of the robot. However, when I added the modifications to joint2 in the files for exercise 2.7.1 and ran t… --- ## [Unit 4 my\_robot\_hardware\_interface.hpp error](https://get-help.theconstruct.ai/t/unit-4-my-robot-hardware-interface-hpp-error/23787)
**Author:** [@zach](https://get-help.theconstruct.ai/u/zach)\ **Replies:** 2\ **Last updated:** [April 18, 2023, 8:06am UTC](https://get-help.theconstruct.ai/t/unit-4-my-robot-hardware-interface-hpp-error/23787 "2023-04-18T08:06:33Z")
I followed the steps on Unit 4 and it seems like the hardware\_interface files are not linking properly. Any ideas on what the issue could be? This is how I created the pkg ros2 pkg create --build-type=ament\_cmake my… --- ## [Unit 3 - Simulation Robot took a lot of time (significantly) to load](https://get-help.theconstruct.ai/t/unit-3-simulation-robot-took-a-lot-of-time-significantly-to-load/23691)
**Author:** [@PhongNguyen](https://get-help.theconstruct.ai/u/PhongNguyen)\ **Replies:** 9\ **Last updated:** [April 13, 2023, 3:24pm UTC](https://get-help.theconstruct.ai/t/unit-3-simulation-robot-took-a-lot-of-time-significantly-to-load/23691 "2023-04-13T15:24:08Z")
The robot took a lot of time to load. I try to switch back to Unit 1 and the robot loaded fine for that unit. I don’t know why it took significantly more time to load for Unit 3. Because of that, I cannot do anything … --- ## [Unit 7 - Custom Controller always dies](https://get-help.theconstruct.ai/t/unit-7-custom-controller-always-dies/21816)
**Author:** [@marcin.czeczko](https://get-help.theconstruct.ai/u/marcin.czeczko)\ **Replies:** 5\ **Last updated:** [January 31, 2023, 11:02am UTC](https://get-help.theconstruct.ai/t/unit-7-custom-controller-always-dies/21816 "2023-01-31T11:02:57Z")
Does anyone finished with success unit 7. Once I configure my\_robot\_bringup controllers are dying on startup. I found out the joint\_state\_broadcaster had wrong type, once fixed it, only rrbot\_controller process is dying… --- ## [Unit 8 - \[Bug\] - Solo Robot is not showing up in simulation window](https://get-help.theconstruct.ai/t/unit-8-bug-solo-robot-is-not-showing-up-in-simulation-window/21830)
**Author:** [@marcin.czeczko](https://get-help.theconstruct.ai/u/marcin.czeczko)\ **Replies:** 2\ **Last updated:** [January 30, 2023, 1:15pm UTC](https://get-help.theconstruct.ai/t/unit-8-bug-solo-robot-is-not-showing-up-in-simulation-window/21830 "2023-01-30T13:15:43Z")
Hi, Looks like the issue Solo robot is not spawning in gazebo described here happens again. Console shows it is showing up, but simulation window shows just robot stand. In the first steps of the unit 8 I need to… --- ## [\[Bug\] Unit 8 - description points wrong location](https://get-help.theconstruct.ai/t/bug-unit-8-description-points-wrong-location/21846)
**Author:** [@marcin.czeczko](https://get-help.theconstruct.ai/u/marcin.czeczko)\ **Replies:** 1\ **Last updated:** [January 24, 2023, 11:52am UTC](https://get-help.theconstruct.ai/t/bug-unit-8-description-points-wrong-location/21846 "2023-01-24T11:52:49Z")
Screenshot of the error Error details ros2\_control\_course/unit6 folder doesn’t have packages as described on the left side. --- ## [Solution to Exercise 2.7.1 issue](https://get-help.theconstruct.ai/t/solution-to-exercise-2-7-1-issue/19409)
**Author:** [@pwspania](https://get-help.theconstruct.ai/u/pwspania)\ **Replies:** 5\ **Last updated:** [September 23, 2022, 7:32am UTC](https://get-help.theconstruct.ai/t/solution-to-exercise-2-7-1-issue/19409 "2022-09-23T07:32:00Z")
After copying the solution, deleting the robot, rebuilding, sourcing, and running ros2 topic pub command, joint 2 is still limp and joint 1 also doesn’t move. Everything up till this part seemed to work correctly. In th… --- ## [Ros2 control framework unit1 intro, not able to contact service /controller\_manager](https://get-help.theconstruct.ai/t/ros2-control-framework-unit1-intro-not-able-to-contact-service-controller-manager/18889)
**Author:** [@damien8181](https://get-help.theconstruct.ai/u/damien8181)\ **Replies:** 4\ **Last updated:** [August 31, 2022, 1:33am UTC](https://get-help.theconstruct.ai/t/ros2-control-framework-unit1-intro-not-able-to-contact-service-controller-manager/18889 "2022-08-31T01:33:25Z")
I just started the ros2 control framework course and the very first ros2 command produces an error: The command $ ros2 launch unit1\_demo load\_controllers.launch.py which is supposed to show a successful load of the co… --- ## [Got "access deny" from final project solution of ROS2\_Control Framework Course](https://get-help.theconstruct.ai/t/got-access-deny-from-final-project-solution-of-ros2-control-framework-course/18386)
**Author:** [@Kane168](https://get-help.theconstruct.ai/u/Kane168)\ **Replies:** 2\ **Last updated:** [July 28, 2022, 6:39am UTC](https://get-help.theconstruct.ai/t/got-access-deny-from-final-project-solution-of-ros2-control-framework-course/18386 "2022-07-28T06:39:38Z")
In 6.7 Hints and Solution, there is a link named “Course project solution”, Course project solution. When I click this link and the web page shows: This XML file does not appear to have any style information associated… --- ## [Controller manager not available](https://get-help.theconstruct.ai/t/controller-manager-not-available/18313)
**Author:** [@vetle.tjohansen](https://get-help.theconstruct.ai/u/vetle.tjohansen)\ **Replies:** 3\ **Last updated:** [July 21, 2022, 8:22am UTC](https://get-help.theconstruct.ai/t/controller-manager-not-available/18313 "2022-07-21T08:22:33Z")
Hello, I’ve tried to complete unit 3 ( Hardware Interface Implementation Template) but it seems like the controller manager not working right? Followed unit 3, three times now and I get the same result every time. Robo… --- ## [Knowledge Check for Course Introduction - Not working](https://get-help.theconstruct.ai/t/knowledge-check-for-course-introduction-not-working/18219)
**Author:** [@vetle.tjohansen](https://get-help.theconstruct.ai/u/vetle.tjohansen)\ **Replies:** 2\ **Last updated:** [July 18, 2022, 9:58am UTC](https://get-help.theconstruct.ai/t/knowledge-check-for-course-introduction-not-working/18219 "2022-07-18T09:58:31Z")
Hello, I’m new here so i don’t really know how the system is supposed to work, but i guess when I’m at unit three and the progress bar is still at 0%, something is wrong or i need to do the knowledge check for each unit… --- ## [Solo robot is not spawning in gazebo](https://get-help.theconstruct.ai/t/solo-robot-is-not-spawning-in-gazebo/18067)
**Author:** [@noam92](https://get-help.theconstruct.ai/u/noam92)\ **Replies:** 3\ **Last updated:** [July 5, 2022, 7:44am UTC](https://get-help.theconstruct.ai/t/solo-robot-is-not-spawning-in-gazebo/18067 "2022-07-05T07:44:44Z")
Hey Im trying to make the course project. after sourcing colcon and source the workspace i try to spawn the solo robot with the provided launch ros2 launch spawn\_solo spawn\_solo.launch.py i receive the output but…