Hexapod-ROS controller Wrong

Hi, i am trying controlling a Hexapod robot in isaac sim Via ROS-Bridge and it turns out flying far away though.
Here is the scene, action graph and the joint settings.
And i’ve tried readjust its damping and stiffness, then sent position cmd only to Joint1 and no use.
Can you help with it?

Hi @ShawnZhou997 - Are you following this document?

yes, sir. @rthaker
I am using ROS instead of ROS2 and following the other document.
There seems to be no documents about ROS&Wheeled robots Via POSITION control mode.
have I missed it?

if you are doing pure position control, you should have some damping on your joints. Stiffness still should be bigger than damping, but damping shouldn’t be 0.

Also, have you checked if your robot isn’t flying away because of other forces such as self-collision? Try to start with no action graph, just the robot on the stage, press play, does it do anything funny? and then move the joint inside the property window (i.e. setting the target position), does it move as expected?