A Comparative Study of STPA Hierarchical Structures in Risk Analysis: The Case of a Complex Multi-Robot Mobile System

Autonomous multi-robot systems are among the most complex systems to control, especially when those robots navigate in hazardous and dynamic environments such as chemical analysis laboratories which include dangerous and harmful products (poisonous, flammable, explosive...). This paper presents an approach for systems-complex and theoretic safety assessment, also it considers their coordinating, cooperating and collaborating using different control architectures (centralized, hierarchical and modified hierarchical). We classified those control architectures according to their properties, and then we used a systems-theoretic hazard analysis technique (STPA) to identify the potential safety hazard scenarios and their causal factors.