A large application domain for multi-robot teams involves task-oriente
d missions, in which potentially heterogeneous robots must solve sever
al distinct tasks. Previous research addressing this problem in multi-
robot systems has largely focused on issues of efficiency, while ignor
ing the real-world situated robot needs of fault tolerance and adaptiv
ity. This paper addresses this problem by developing an architecture c
alled L-ALLIANCE that incorporates task-oriented action selection mech
anisms into a behavior-based system, thus increasing the efficiency of
robot team performance while maintaining the desirable characteristic
s of fault tolerance and adaptivity. We present our investigations of
several competing control strategies and derive an approach that works
well in a wide variety of multi-robot task-oriented mission scenarios
. We provide a formal model of this technique to illustrate how it can
be incorporated into any behavior-based system.