A Hierarchical State-Machine-Based Framework for Platoon Manoeuvre Descriptions

This paper introduces the SEAD framework that simplifies the process of designing and describing autonomous vehicle platooning manoeuvres. Although a large body of research has been formulating platooning manoeuvres, it is still challenging to design, describe, read, and understand them. This difficulty largely arises from missing formalisation. To fill this gap, we analysed existing ways of describing manoeuvres, derived the causes of difficulty, and designed a framework that simplifies the manoeuvre design process. Alongside, a Manoeuvre Design Language was developed to structurally describe manoeuvres in a machine-readable format. Unlike state-of-the-art manoeuvre descriptions that require one state machine for every participating vehicle, the SEAD framework allows describing any manoeuvre from the single perspective of the platoon leader. %As a proof of concept, the proposed framework was implemented in the mixed traffic simulation environment BEHAVE for an autonomous highway scenario. Using this framework, we implemented several manoeuvres as they were described in literature. To demonstrate the applicability of the framework, an experiment was performed to evaluate the execution time performance of multiple alternatives of the Join-Middle manoeuvre. This proof-of-concept experiment revealed that the manoeuvre execution time can be reduced by 28 \% through parallelising various steps without considerable secondary effects. We hope that the SEAD framework will pave the way for further research in the area of new manoeuvre design and optimisation by largely simplifying and unifying platooning manoeuvre representation.