Motivation and research problem

Earth-based structures have a very low environmental impact and provide a healthy indoor climate to inhabitants, thus representing sustainable alternatives to conventional structures. However, labor-intensive, time-consuming processes and the requirement of manual building skills restrict the productivity of earth construction processes, which are based on a centuries-old state of practice. To overcome the current difficulties, principles of additive manufacturing (AM) and smart sensing technologies may be coupled with earth construction processes towards so-called “earth-based AM”, increasing the quality and advancing the productivity. Through digitalizing earth construction processes, earth-based AM has the potential to transform the current practice for cob, adobe, and rammed earth into a smart manufacturing process. Evidently, to efficiently conduct earth-based AM, a formal description is necessary, which allows adequately gathering, storing, analyzing, and describing the information required for earth-based AM. Furthermore, digital data models, providing the basis for construction robots to “print” earth-based structures without information loss, must be extended or developed anew.

Research objectives and expected results

The proposed research project aims to advance the digitalization of earth-based AM, or “earth printing”, by providing a formal conceptual basis for a new methodology for data modeling in earth-based AM. The methodology will generically define earth-based structures and the overall process of earth-based AM. The methodology, although valid for additive manufacturing in general, is expected to bridge information gaps in the digital workflow of earth printing without information loss, enabling

1. Modeling of the parameters and the semantic relationships within earth-based AM (process parameters), including sensing technologies that support process planning, process monitoring, and process control,
2. Integration of earth-based materials into the digital workflow of earth-based AM (“digital material”), including material composition, material properties, and material behavior relevant to extrudability and buildability (material parameters), and
3. Instantiation of the digital models (based on geometry parameters) for designing, simulating, and printing earth-based structures.

The methodology will be verified using a verification concept for model checking and reasoning to be proposed for earth-based AM, building upon formal logic, to increase the quality and the productivity of earth-based AM. For validation, use cases will be defined and experimental tests will be conducted using a robotic printing system. As a result, the outcome of this project is expected to provide a formal basis that semantically describes all information relevant to earth-based AM, including structures and processes, to further advance earth-based AM towards smart manufacturing.