Why does a robot model push away objects whenever it touches them?
I am simulating a robotic manipulator from urdf files. The robot is supposed to interact with objects in its environment, but whenever any part of the robot touches an object, the object is pushed back some distance - it is almost as if there is some repulsion acting between the robot and the object, resulting in the application of an opposing force. I know this might be a problem with the robot's collision and inertia properties, but I do not have any clue on how to debug it. Can someone please guide me? Thanks
PS: I do not think that it is a problem with the object models, since I am using object models supplied by gazebo such as a simple box and coke can for now. When 2 objects touch each other, they have no problem in maintaining the contact, the problem is only when the robot touches the object.
I am showing a video with collision and transparent visualization on, which depicts what happens when a model is brought into contact with the robot link
I can see that some of the joints are rotating without any applied force in the transparent view. Is this the cause of the problem, i.e. is the robot model itself unstable? With a different robot model (UR5) also, the object is thrown away, but the robot itself does not move like the Barrett WAM