Construction robots



‘How can we build differently?’ Prof. Pierre Latteur first answered this question some time ago: the drone enthusiast initiated research on how drones could be used on a construction site. Today he has another answer: after construction drones, construction robots!

A brief video was popular among construction professionals and architects: 7,000 views in 10 days on LinkedIn. It shows a robot turning every which way to carve notches in logs. The performance seems neither extraordinary nor innovative, but it may have interesting implications. But why care about how a robot nicks a tree trunk?

LThe answer comes from the deadlock in which timber construction finds itself. Admittedly, there are more and more detached houses with wooden frames, but there’s rarely anything larger, such as office buildings or shopping centres. ‘This is mainly due to the fact that wooden structures are more expensive than concrete ones,’ explains Prof. Latteur, head of the Louvain School of Engineering’s Civil and Environmental Engineering Group. ‘Wood undergoes many transformations. When it arrives at the sawmill, it’s worth €100/m3. Transformed into glued-laminated or cross-laminated timber, it’s worth up to €1,000 euros/m3, while concrete costs €500-600/m3. This is a significant difference.’

Using tree trunks

From there was born a project in partnership with Mobic in Harzé, Belgium: if we want to build using wood, we must offer wood that hasn’t been excessively processed, and is less expensive than concrete. The least processed: tree trunk logs. For the Pairi Daiza zoo and botanical garden, in Brugelette, Belgium, Mobic has just built 10ha of carports (7,000 parking spaces!) made of tree trunk logs and topped by 62,750 photovoltaic panels. On the strength of this experience, convinced that wood should be transformed as little as possible, Prof. Latteur and Mobic launched a research project a year ago. Business PhD student Julien Geno, funded by the Wallonia Civil Service (SPW), was hired part-time within the company and part-time at the university to develop the means of designing and building structures using tree trunk logs.

Wood’s additional cost doesn’t explain everything, however, for that’s always been the case. So why has this ‘robotic’ solution, and the notion of using tree trunk logs to build tall buildings, taken so long? ‘Two reasons,’ explains Prof. Latteur. ‘First, parametric design software, which isn’t just design software but software in which all object parameters are implemented, simply didn’t exist. Second, robots arrived in construction slowly, for safety reasons. Mobic is still the only company in Belgium that manufactures wooden structures prefabricated by robots. But it brought the robots from the auto industry and had to reprogram them.

Three stages

The system was developed over a year by construction engineering student Justin Goosse, in his recently completed master’s dissertation. In the first stage, logs are modelled by photogrammetry (a technique that reconstructs 3D models from simple photos) and the models are placed in a database. Second, the structure and notches are designed based on the models (the system recognises the most suitable logs according to factors such as the position in the structure and the notches to be made). Third, the robot notches the logs. This is all done with great ease by the user: if you want to change the depth of a notch, all you have to do is move the cursor on the monitor.

We must now continue to develop the software before any idea of commercialisation,’ concludes Prof. Latteur. ‘It was designed for a particular structure, the one in the video. Now we need to make it compatible with any structure.

Henri Dupuis

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A glance at Pierre Latteur's bio

Seeing companies associated with Pierre Latteur's research is no surprise to those who know his background. During his master’s degree programme in civil engineering in construction (UCLouvain 1994), he spent six months via the Erasmus programme at the prestigious Technological University of Delft in the Netherlands. He began his career in research, as an engineer in the UCLouvain Civil Engineering Laboratory. He quickly earned his engineering PhD at VUB (2000), on structure optimisation, while becoming a professional architect through his experience with the well-known firm Samyn & Partners. Keeping one foot in academia, he became a guest researcher at the prestigious Ecole Polytechnique Fédérale de Lausanne (Switzerland).

He prioritised the private sector for seven years as a structural engineer and project manager with the Brussels-based company SETESCO, while teaching at the Brussels Ecole des Arts et Métiers (ECAM) and serving as a part-time associate professor at the University of Liège, a position he still holds today. In 2006, he became director of the stability studies office of Tractebel Development Engineering (at the time, GDF-SUEZ). He left this undoubtedly coveted position in 2013 to answer UCLouvain’s call to become a professor at the Louvain School of Engineering. Since 2015, he has led the Civil and Environmental Engineering Group. Prof. Latteur’s interests include gardening, travelling, hiking and boating, and, of course, piloting drones, for which he obtained a class 1 licence two years ago.

Published on October 05, 2020