Modeling service choreographies and collaborations for autonomous mixed-fleet systems: using BPMN, IEC 61499, and SysML

Abstract Complex logistics systems may require the cooperation of a variety of subsystems, such as robots, autonomous vehicles, and human-operated devices. These so-called mixed-fleet systems are found in logistics use cases, which demand high flexibility. Hence, the choreography that orchestrates the involved software systems, spanning edge to cloud, must be adaptable and reconfigurable. Enabling to add or remove subsystems flexibly during runtime requires a strong decoupling, which is found in multi-agent systems. In this paper, we explore a model-driven engineering process for service choreographies of flexible, heterogeneous, and autonomous mixed-fleet systems. Each complex process is decomposed into services and tasks, which can then be flexibly assigned to available actors. The resulting layered service-oriented architecture is realized as an event-based system. We define requirements for the modeling of processes, services, interactions, and event objects, before evaluating different modeling languages based on their applicability for each layer, i.e., BPMN, IEC 61499, and SysML. We then demonstrate and evaluate our architecture using a port logistics use case. The results show that the three languages are suitable candidates for modeling event-based process models, although they have varying advantages and disadvantages. Overall, their diagrams can be used to capture service choreography models for decentralized systems. Future work will investigate how these models can be validated comprehensively and used for system implementation.