question on PID controller in ROS [closed]

edit

Update1: In gazebo simulation. Concerning the ros_controller config yaml file for PID specification. Update2: While rqt_plot works now it is sporadic - gazebo stops responding to the commands. This can happen consistently after a reset world or model pose. Update3: In the text when I say apply force I mean via published command and not via the gazebo tab

If no internal force is applied to a joint; Should the the PID controller adjust the joint.

I have a model where an incorrect PID setting was causing the model to move without an internal force being applied to any joint. The controller caused the model to jump off the gazebo grid. By adjusting the PID I was able to stop this but should this have been at all?

    I had taken this setting used in a tutorial  
     {p: 100.0, i: 0.01, d: 10.0}  
    and changed to this one and the robot stop jumping off screen
     {p: 0.001, i: 0.001, d: 0.001}


at no time did I apply a force to the joints

When I start rviz with the controllers the robot moves on its own showing odometry movement. When I again change the setting to something smaller like

    pid: {p: 0.000001, i: 0.000001, d: 0.000001}

    at   
     {p: 0.00, i: 0.00, d: 0.00}   
    the robot did not move even when a force was applied.  

the robot does not move and now I can apply a force and have it respond only to the force applied.

Is this correct for the controller?