  Field robot systems have recently been applied to a wide range of research
fields. Making such systems more automated, advanced, and activated requires
cooperation among heterogeneous robots. Classic control theory is inefficient
in managing large-scale complex dynamic systems. Therefore, the supervisory
control theory based on discrete event system needs to be introduced to
overcome this limitation. In this study, we propose a hybrid systems-based
hierarchical control architecture through a supervisory control-based
high-level controller and a traditional control-based low-level controller. The
hybrid systems and its dynamics are modeled through a formal method called
hybrid automata, and the behavior specifications expressing the control
objectives for cooperation are designed. Additionally, a modular supervisor
that is more scalable and maintainable than a centralized supervisory
controller was synthesized. The proposed hybrid systems and hierarchical
control architecture were implemented, validated, and then evaluated for
performance through the physics-based simulator. Experimental results confirmed
that the heterogeneous field robot team satisfied the given specifications and
presented systematic results, validating the efficiency of the proposed control
architecture.
