ROS Control 101 quiz help

I need a hint or something more than what is provided. I have the controller for the quiz compiled correctly and loading it will control a joint and move it to what I’m almost certain is the correct position. I just don’t know how to make the next joint move. I have watched Ricardo’s #54 live class on controllers, a 6 part series on controllers, looked at the controller source code. Searched this category and the cpp category. I know exactly why the JointStateController is always required. I know the joint name comes from the parameter server which get the names from the yaml file. I know what command each of the 3 possible controllers take, and the PID’s don’t mean anything when writing a custom controller. What I don’t know is cplus. I’m almost certain I know the value for the next joint. I have watched hours of videos I now know and understand much more than I would have if had known how to accomplish this last part. How can I move more than one joint or specify within the cpp file the next joint position. I have literally spent all weekend studying and researching this topic.
Please help.

Hello @hskramer ,

What do you mean by moving more than 1 joint? There’s no need to move more than 1 joint for solving the quiz, you only need to move the joint shoulder_lift_joint_position_controller.


From the image given it looked like the wrist joint needed to be moved to another position also. I’m
a perfectionist so if I think there’s something that needs to be done I try to do it. Well I still learned a lot so that’s OK.