The topic /joint_states is empty. I cannot get the dual robot arms position through get_current_state().

[guningquan]

Hi, thanks for your tutorials. I can bring up my two ur5 robot arms simultaneously.
And, I created my dual_ur5_moveit_config (ros1 melodic), connecting the config package to the real robots successfully.
But, I cannot get the positions of the bob arm and alice arm. The error is Failed to fetch current robot state.
The reason is that the bringup method of the Tutorials published /bob/joint_states and /alice/joint_states topics respectively.
But moveit_commander.move_group.MoveGroupCommander.get_current_state() is to get the position from topic /joint_states.
I input rostopic echo /joint_states, the output is empty.
Then I remap the topic rosrun topic_tools relay alice/joint_states joint_states. But this way only allows me to get the alice arm position correctly.
Why the topic of /joint_states is empty?
Or, How can I get the correct positions of the two arms simultaneously without remap?

[VinDp]

Hi @guningquan,

sorry for the late reply, to solve your problem you can simply use 2 relays:

• rosrun topic_tools relay alice/joint_states joint_states
• rosrun topic_tools relay bob/joint_states joint_states

In this way you should have the joint states of both robots on /joint_states.

[VinDp]

Hey @guningquan , I will close the issue since some time has passed. Feel free to reopen if still relevant.