Humanoid Robot Swarm Synchronised Using Quorum Sensing

05-16-2012 • http://www.technologyreview.com

In recent years, various companies and labs have developed impressive humanoid robots that walk, shuffle and even run. Some even dance in groups of up to 20, performing sophisticated choreographed routines.

This kind of synchronisation is no easy task. One way to do it is have one robot as the leader, broadcasting details of its movement and position over a network that the other robots all follow.

The trouble is that network dynamics are not as predictable as choreographers would like. Small delays of half a second or so are common while some messages can be delayed by several seconds. That's clearly not good enough for a dance routine or any other type of synchronised behaviour.

So the approach preferred by roboticists is to program each robot with the dance routine, synchronise their internal clocks at the start of the performance and then leave them to it.

The advantage is that If the performance is reasonably short, the chances of the clocks becoming desynchronised can be made small. The disadvantage is that if the robots become desynchronised--if one falls over, for example--there is no way to regain synchronisation.

So roboticists have been searching for a better form of synchronisation that is more robust to the various trials and tribulations that befall robotic dancers. Today, Patrick Bechon and Jean-Jacques Slotine at the Massachusetts Institute of Technology in Cambridge, reveal a new approach based on the biological phenomenon of quorum sensing.

Biologists have long puzzled over the ability of bacteria and social insects to sense not only the presence of compatriots but their number and to synchronise their behaviour.