Interaction between 2 objects in Gazebo

edit

I am working on a "pick and do" operation in ROS and simulating the same in Gazebo. I have model of a wrench, which is attached to my own gripper in URDF. The gripper in turn is attached to UR5. This setup has to rotate a knob on a panel. But as soon as the gripper touches the knob, the panel flies off even though the mass of the panel has been defined as 800kg in the sdf file. https://youtu.be/7vpE6pHe0x8

I tried the same setup by replacing my gripper with PR2 gripper (and without the wrench) and I getting decent results. So my guess is, again there seems to be some problem with the inertia of my gripper and the wrench. Would be great if anyone could help me in defining it correctly. Remove the .jpg at the end of the file name. C:\fakepath\gripper.stl.jpg

Edit 1: Gripper URDF : C:\fakepath\gripper.urdf.xacro.jpg

Panel sdf: C:\fakepath\model.sdf.jpg

Edit 2: Here's the video after making the panel model static. https://youtu.be/eP29QGYoQhY

Edit 3: The problem disappears after I enable kinematic property in Gazebo GUI for each link of UR5. I am not sure if this is the right solution though. Also, I can't do this with

<gazebo reference="ur5_arm_wrist_3_link">
    <selfCollide>1</selfCollide>
    <kinematic>1</kinematic>
    <canonical>1</canonical>
</gazebo>

The only property which changes is selfCollide. How can I change this through URDF? I haven't found any documentation. I could save the world file with the entire setup. Can I load the world file instead of URDF for UR5 as well? How can I set robot_description parameter in that case?

Thanks!