Heterogeneous multi-robot cooperation

Abstract

This report addresses the problem of ac hieving fault toleran t cooperation within small to mediumsized teams of heterogeneous mobile robots I describe a soft w are arc hitec ture I ha edev v eloped called ALLIANCE that facilitates robust fault toleran t cooperativ e con trol and examine n umerous issues in cooperativ e team design ALLIANCE is a fully distributed arc hitecture that utilizes adaptiv e action selection to ac hiev e cooperativ e con trol in robot missions in olving loosely coupled largely independen v t tasks The robots in this arc hitecture possess a v ariet y of highlev el functions that they can perform during a mission and m ust at all times select an appropriate action based on the requiremen ts of the mission the activities of other robots the curren ten vironmen tal conditions and their o wn in ternal states Since suc h cooperativ e teams often w ork in dynamic and unpredictable en viron men ts the soft w are arc hitecture allo ws the team mem bers to respond robustly and reliably to unexpected en vironmen tal c hanges and modications in the robot team that ma y occur due to mec hanical failure the learning of new skills or the addition or remo al of robots v from the team b yh uman in terv en tion In addition an extended v ersion of ALLIANCE called LALLIANCE incorporates a simple mec hanism that allo ws teams of mobile robots to learn from their previous experiences with other robots allo wing them to select their o wn actions more ecien tly on subsequen t trials when w orking with familiar robots on missions composed of independen t tasks This mec hanism allo ws a h uman system designer to easily and quic kly group together the appropriate com bination of robots for a particular mission since robots need not ha e a priori kno v wledge of their teammates The dev elopmen t of ALLIANCE and LALLIANCE in olv v ed researc hon a n um ber of topics fault toleran t cooperativ econ trol adaptiv e action selection distributed con trol robot a areness of team mem w ber actions impro ving eciency through learning in terrobot comm unication action recognition and local v ersus global con trol This report describes eac h of these topics in detail along with experimen tal results of in estigating these issues v both in sim ulated and in ph ysical mobile robot teams Iamnot a are of an w y other cooperativ econ trol arc hitecture that has exhibited the com bination of fault tolerance reliabilit  adaptivit  and eciency possible with ALLIANCE y y and LALLIANCE and whic h has been successfully demonstrated on ph ysical mobile robot teams