SPIRAL DEVELOPMENT APPROACH FOR DESIGN AND VALIDATION OF LARGE-SCALE EXTRUSION-BASED AUTONOMOUS CONSTRUCTION SYSTEMS

Autonomous construction systems (ACSs) have become a very important area of research in several domains, particularly in expeditionary site preparation, extraterrestrial exploration and base construction, and disaster response. While these systems range from single vehicles to large systems with swarms of autonomous construction equipment, the major need for development is in the extrusion-based autonomous construction systems (EBACSs). These systems use large 3-D printers and supporting equipment to construct buildings and infrastructure in place. This article reviews a major previous study which developed a quasi-general system architecture for EBACSs and uses this as the starting place for further development in system realizability (manufacturing, assembly, and integration) and verification and validation efforts using the spiral development approach. Originally developed for software development projects, the spiral method has become more and more widely used in recent years for all kinds of risky and complex systems engineering work. Most importantly, decisions are made based on risk and the development/design process ends once the stakeholders decide the magnitude of system improvements in each cycle is too small to justify further cumulative cost. This work clearly shows the need and value of a general system architecture for EBACS and a path forward for their continued development and refinement. The conclusions and recommendations generated are relevant for the design and realization of a variety of different EBACSs configurations (gantry systems, robotic arms, delta robots, ground robot teams, and others) and will aid in the more effective realizability and fielding of these systems throughout their life cycle.