  This paper focuses on the teaming aspects and the role of heterogeneity in a
multi-robot system applied to robot-aided urban search and rescue (USAR)
missions. We propose a needs-driven multi-robot cooperation mechanism
represented through a Behavior Tree structure and evaluate the system's
performance in terms of the group utility and energy cost to achieve the rescue
mission in a limited time. From the theoretical analysis, we prove that the
needs-driven cooperation in a heterogeneous robot system enables higher group
utility than a homogeneous robot system. We also perform simulation experiments
to verify the proposed needs-driven collaboration and show that the
heterogeneous multi-robot cooperation can achieve better performance and
increase system robustness by reducing uncertainty in task execution. Finally,
we discuss the application to human-robot teaming.
