If anyone knows about this please help, I'm trying to make this rigged robot knock over a piles of rigid body blocks. Is their any way to do so? I have tried to make the arm a rigid body but then it gets stuck in place, I made it a collision object and it stays with the rigged body but doesnt interact with the objects.
You can also just delete the armature modifier from the mesh, make every segment its own object (separate by loose objects) and then just parent them to each bone (select object, shift select armature, go to pose mode, select the right bone and ctrl-p to parent it).
Then you can just animate the rig as you want and also add rigid body to each segment.
I've had issues with this as well and this is the solution that works well with segmented characters. Rigid body objects don't respond to the armature modifier. To work around this, make the hand a separate object, remove the armature modifier from it, and parent it to the hand bone. Then enable rigid body physics, make it passive, and check animated.
Cubes - A character/avatar pushing objects aside -
To avoid detatching the hand that in this example is already mesh-deforming nicely to it's armature, an INVISIBLE cube (rigid object) is added instead to collide with the large cubes and that parented to the empty that's animating the arm.
The result is the same and it can be moved about and rotated relative to the hand/empty in order to suit the collision. If necessary it can be keyframed to readjust it's orientation for other collisions as often as needed.
If it gets in the way at any stage, ticking and unticking the Dynamic and Animation boxes is not recommended. Simply keyframe it to somewhere convenient.