Explicit vs. Tacit leadership in influencing the behavior of swarms

Many researchers have employed some form of teleoperated leader to influence a robotic swarm; however, the way in which this influence is conveyed has not been well studied. Some researchers employ designated leaders that are known to be leaders by other members of the swarm and hence followed. Others do not impose a leader/follower distinction on the swarm´s algorithms and instead choose to influence the swarm indirectly through controlling one or more of its members. Because the robustness of swarm behavior arises from its many distributed interactions, influence through designated leaders might render it susceptible to noise or disrupt its coherence by overriding these mechanisms. Conversely, limiting human influence to indirect control through the local effects of a leader might prove too sluggish to allow effective human control. This paper compares leader-based methods of each type, designated as Tacit leadership via consensus (no explicit leader/follower distinction) and Explicit leadership via flooding (influence propagating from leader takes precedence). These methods were compared in simulation and in human experiments finding that explicit leadership led to faster convergence in simulation and better performance in the experiments. Effects of noise were slightly more pronounced for Explicit leaders and cohesion slightly poorer.