Reconfigurable Formwork System for Vision-Informed Conformal Robotic 3D Printing

Abstract

Robotic additive manufacturing has garnered significant research and development interest due to its transformative potential in architecture, engineering, and construction as a cost-effective, material-efficient, and energy-saving fabrication method. However, despite its potential, conventional approaches heavily depend on meticulously optimized work environments, as robotic arms possess limited information regarding their immediate surroundings (Bechthold, 2010; Bechthold & King, 2013). Furthermore, such approaches are often restricted to planar build surfaces and slicing algorithms due to computational and physical practicality, which consequently limits the feasibility of robotic solutions in scenarios involving complex geometries and materials. Building on previous work (Çapunaman et al., 2022), this research investigates conformal 3D printing of clay using a 6 degrees-of-freedom robot arm and a vision-based sensing framework on parametrically reconfigurable tensile hyperbolic paraboloid (hypar) formwork. In this paper, we present the implementation details of the formwork system, share findings from preliminary testing of the proposed workflow, and demonstrate application feasibility through a design exercise that aims to fabricate unique components for a poly-hypar surface structure. The formwork system also offers parametric control over generating complex, non-planar tensile surfaces to be printed on. Within the scope of this workflow, the vision-based sensing framework is employed to generate a digital twin informing iterative tuning of the formwork geometry and conformal toolpath planning on scanned geometries. Additionally, we utilized the augmented fabrication framework to observe and analyze deformations in the printed clay body that occurs during air drying. The proposed workflow, in conjunction with the vision-based sensing framework and the reconfigurable formwork, aims to minimize time and material waste in custom formwork fabrication and printing support materials for complex geometric panels and shell structures.