Question Applying gravitational force of an object to robotic arm while picking up

I am working on a robotic arm pick-up and place project. I use a haptic device to control the robotic arm. While the robotic arm picks an object, I want to apply the gravitational pull force to the haptic device. The gravitational pull is the force that grabbed object is accelerating down. The simulation needs to be as realistic as possible. So gravity should be applied when an object is lifted from one side while the other side is still on earth.

I want to apply less force when the other side is still on the ground and full force when it is fully lifted. So far I could not be able to find a way to do this.

My idea is to attach a script to every grabbable object and calculate its gravity force while grabbing. Then I can apply the force to the haptic device to give a feeling of the object pick-up. So far I could not do that.

Any idea? How can I do that?

 

Hello,

Perhaps you could use a hinge joint, or configurable joint to lift, and let the physics engine do the math?
https://docs.unity3d.com/ScriptReference/Joint-currentForce.html

 

Hello. Thanks for the response. I am experimenting with articulation body at the moment. Is there a way to do this with articulation body as well?

I chose an articulation body over a rigid body because the gripped object is slipping down from the robot arm when it has a rigid body. But an articulation body does not let it. So I think the articulation body is better for pick-up and place by a robotic arm.

 

Just to dig into the documentations then, to see which joints is able to return current forces?
https://docs.unity3d.com/Manual/class-ArticulationBody.html

But without a load with a rigidbody with a mass I can't se how the physics engine ever could figure out the forces that has to be applied.