Sensor Systems for Digital Fabrication

The construction industry is currently undergoing major changes due to automation and digitization in all phases of a building's lifetime. The modernization of construction processes has an effect on design, fabrication, assembly, and maintenance of buildings. The goal of this innovation is to boost productivity, enhance sustainability, and maintain a high level of resilience. Achieving these goals requires geometrical information about the fabricated objects and their changes over time with sufficient spatio-temporal coverage, resolution, and accuracy. Digital fabrication is now at the transition from highly controlled lab environments to real world application, and requires the design, planning, and realization of measurement systems with the appropriate technical characteristics and connection to a well-defined reference frame.

Enlarged view: Figure 1 — Figure 1: Post-fabrication scanning of 3D concrete printed columns using a terrestrial laser scanner in the Robotic Fabrication Laboratory (RFL)

- Robotic Fabrication Laboratory (RFL)

Within the scope of the research project “Sensor Systems for Digital Fabrication”, we develop a measurement system and a data processing scheme for 3D shape assessment during digital fabrication of objects. The aim of this research is to generate reliable real-time feedback for controlling the fabrication process. We thus contribute to the interdisciplinary work towards a production process that adapts automatically to insufficient layer thickness, deformations of the just fabricated structure or layers during hydration, deviations of realized from planned surface finish, etc., by adapting the trajectory and execution parameters of the fabricating robot.

We have selected a set of depth cameras mounted on the arm of the fabrication robot as the core of the measurement system for deriving geometric information in real time. We develop experimental implementations of the system for demonstration in two case studies i.e., robotic concrete spraying and 3D concrete printing. The research and these demonstrators are carried out within the external page National Centre of Competence in Research (NCCR dfab) Digital fabrication. We closely collaborate with Gramazio Kohler Research (GKR) and Digital Building Technologies (dbt) in this project.

Enlarged view: Figure 2 — Figure 2: Robot during the rebar mesh scanning, here using two depth cameras on the robot arm (right)

This and other similar contributions to a building process modernization and automation results in an increase of productivity and efficiency, leaving less room for human related errors. This allows for working with inaccuracies and deviations that are inherent to the process in a pro-active way using modern technology. Overall, this also enables digital fabrication experts to produce constructions with enhanced sustainability and reduced impact on the environment. Finally, including sensor solutions in robotic setups designed for construction, opens a door for automatic customized mass production of fabricated objects due to sufficient control during fabrication.

Contact

Prof. Dr. Andreas Wieser

Full Professor at the Department of Civil, Environmental and Geomatic Engineering

Geosensorik und Ingenieurgeodäsie
Stefano-Franscini-Platz 5
8093 Zürich
Switzerland