Active versus passive expression of preference in the control of multiple-robot decision-making

Just like their solitary counterparts, multiple-robot systems must be able to make decisions in response to their environment. However, with a multiple-robot system, one must take care to ensure that the individual robots that compose a system make their decisions in concert with each other. We desire decisions to be made at the system level. In this paper, we investigate four different mechanisms to allow individual robots within a system to express their preference for a particular solution to a system-level problem. All four mechanisms consistently produced unanimous decisions, but had varying ability to produce unanimous decisions of good quality. An approach that we refer to as passive expression of preference performed the best, but had to be tuned to the particular problem being solved. A mechanism that we refer to as active expression of preference exhibited very good performance and required no problem specific tuning, which makes it more universally applicable to the multiple-robot decision-making problem.