Strategies for Robotic in Situ Fabrication

Abstract

Since the construction industry has begun deploying robotic technologies for digital fabrication processes, this direction has mostly been focused on integrating industrial-type robots into off-site prefabrication processes. By contrast, no enabling robotic technology exists today that allows robotic systems to be integrated into in situ construction processes right on the building site. This is mainly because in comparison with robotic prefabrication, robotic in situ fabrication faces fundamental technological challenges. First, buildings are large in scale. In contrast to prefabricating sub-assemblies of a building with stationary robotic systems off-site, in situ robotic systems must be able to fabricate large-scale assemblies at their final location. Second, building sites are poorly structured. As opposed to operate within structured factory conditions, in situ robotic systems must be able to accurately fabricate large-scale assemblies---irrespective of the uncertainties prevalent on-site. To firstly address the challenges imposed by the building scale, this thesis explores the mobile robotic fabrication of continuous and monolithic architectural-scale building components on-site. To further respond to the challenges imposed by the unstructured nature of building sites, and by the uncertainties related to the site, the fabrication, and the material, this thesis investigates the integration of robotic sensing solutions and the implementation of adaptive fabrication control techniques. For the purpose of validating the developed methods and strategies for robotic in situ fabrication, three subsequent case studies are implemented. Each of them utilises a different robotic set-up, once a stationary and twice a mobile, and applies a distinctive material system---that is, loam, bricks, and steel rebar. The research culminates in the third experiment, namely the mobile robotic fabrication of a doubly-curved steel rebar mesh for a reinforced concrete wall. This demonstration provides the unique opportunity to present robotic situ fabrication not only as a future vision, but applied in the context of a real construction project.