Attach object to mulitple robot arms

edit

Hello,

I got the following situation: Setup

I want to pick up an object (the dark grey one in the middle) with multiple robots. In the beginning I am trying to get it to work with two robots but I want to scale it up later.

The problem: The robots fly through the air when I am trying to attach the to the object or when I am trying to lift the object.

The dark grey object is one block that is separated with a linear joints.

The robot arms attach with this plugin to the object. I changed the joint I am spawning in dynamically to attach the endeffector of the arm with the object to a ball joint.

The linear joint and the ball joint are my first tries to make it more independent and let it have a little bit of freedom so no big forces are there that will throw my robots around. But still: The robots fly through the air.

My last tries were to play with the kd and the minDepth parameters, but still got the same problem with the robots go flying.

Is there any possibility to attach an object to multiple robot arms and lift the object with the robot arms? (I think the problem is that the construct is overconstrained. But I have no idea how to solve this as there should be plenty of freedoms with the linear and ball joint I introduced.)

Or is it only possible with a gripper attached to each end effector that grasps the object?

Are there any other possibilities to attach the object to the endeffector in the same style like I am doing now? So attaching the object to the empty endeffector (like a vacuum tool).

Thanks for any help and have a nice day! Heenne

EDIT: Linkto crosspost in answers.gazebosim.org.