[Bill_B]

To be useful, the routine would have to have a "pause" that leaves one side still touched down while a partner joins it. If you pause too soon, there might not be enough room for the partner. Too late and the bridge tips up going to balance without the partner.

imaginary two-robot sequence.
alliance agrees which two robots will attempt balance on their bridge.
also agree which is balancer and which is "passenger" B and P henceforth.
both B & P to approach from the same side.
B lowers and mounts bridge advancing toward center.
B pauses with enough room for P.
P follows onto bridge until fully supported by sloping surface.
P stops and "brakes" if needed.
B resumes auto balance mode by driving past fulcrum to get both balanced.
(problem if B cannot move far enough away from P to balance bridge. is this possible? likely?)