I took an available model of a robot arm and turned it upside down to make a leg with a wheel instead of a foot. I have it rigged and it seems to be working. I even have a driver working to spin the wheel when the main bone moves in x.
I want to make a robot with 4 of these legs, so I selected all parts of the leg, including the armature. I duplicated it 4 times and moved each into position at offsets of xy +/- 0.125 (near the corners of the cube)
Finally, I wanted to join all the armatures into one, so I selected all 4 and hit ctrl-J. They joined, but most of my robot parts flew off the screen.
Am I missing something? I’ve attached the blend if anyone wants to take a look.
stair_climber3.blend (1.66 MB)