Hand-Drawn Digital Fabrication: Calibrating a visual communication method for robotic fabrication

According to the 2016 Mckinsey report, the global construction industry is one of the least productive [1], which can be attributed to a minimal implementation of digital and automation technology [2]. This research argues that this relates to a skill base since very few, if any, construction workers can operate digital fabrica-tion systems. Here, a digital model is considered foundational knowledge and is used to communicate with a fabrication unit. The difficulty lies in communicating the digital model to the fabrication machine, which arguably requires a level of specialist knowledge. However, history shows that other methods of communi-cating complex construction information have existed, such as 1:1 on-site draw-ing, which used to be made by architects or construction workers to communicate complex information related to constructing jigs or building components [3]. We propose an alternative where we learn from history and amalgamate that knowledge with a robotic framework. We present the calibration process behind a parametric visual feedback method for robotic fabrication that detects on-object hand-drawn markings and allows us to assign digital information to detected markings. The technique is demonstrated through a 1:2 prototype that is fabricat-ed using an ABB IRB 120 robot arm.