vacuum gripper plugin is not working

[mazik1496]

I was looking for a solution based on the last post(#47). As a result of searching for the cause of not sticking to the wall, it was inferred that the vacuum gripper's plugin did not work properly, and it was confirmed through the test model (In the picture above, the red cylinder is the gripper link, and this link should pull the blue box).

In the picture above, can you tell me where I need to improve for the gripper plugin to work? The source code is below.

----urdf.xacro code-----

----gazebo.xacro code-----

----gripper.py code-----

[mazik1496]

As a result of checking the current log, it was confirmed that the plugin of gazebo_ros_vacuum_gripper was loaded and the status was also turned on. However, a phenomenon occurs that the operation does not run after that. What could be the cause for this?