Helping robots find their way around the construction maze
By improving how unmanned ground vehicles see and navigate complex, cluttered construction sites, automation is set to transform tasks like site mapping and monitoring.
Have you ever wondered how the spaces around you — apartments, offices, shopping complexes — are built?
From site inspections and planning to logistics and assembly, construction is a highly coordinated process involving a network of interconnected suppliers
Issue 04 | January 2025
and workflows. Human hands and eyes have traditionally guided the process every step of the way, ensuring that every i is dotted and every t is crossed.
But today, the construction sector faces a fresh challenge: labour shortages, inflamed by the Covid-19 pandemic. Even as construction demands rise, almost a third of employers are struggling to hire skilled staff.1 Much of this gap is due to an ageing workforce.
Automation is emerging as a solution to fill this gap, with robots stepping in to support various tasks alongside human workers, including building mapping and inspection. Dr Justin Yeoh from the Department of Civil and Environmental Engineering, College of Design and Engineering, National University of Singapore, offers two solutions that could transform the deployment of unmanned ground vehicles (UGVs) for such roles.
In a study, published in the Journal of Computing in Civil Engineering on 9 July 2024, Dr Yeoh and his team introduced a method that uses video footage from earlier construction stages to map out navigation routes. This allows UGVs to manoeuvre through busy construction sites unimpeded by scattered materials and equipment.
In another study, published on 16 April 2024 in the same journal, the researchers tackle a different challenge: ensuring that UGVs align what they ‘see’ in realtime with digital building plans, or Building Information Modelling (BIM). This alignment enables UGVs to accurately compare on-site conditions with digital blueprints — enhancing reliability in inspections.
Cutting through the noise
The only constant at construction sites is change. These environments are in constant flux — workers moving materials and equipment, debris falling, layouts shifting throughout the day. It’s challenging enough for humans — imagine the complexity for robots.
“UGVs are great for tasks such as monitoring site progress, but construction sites are tough environments for them to navigate. Maps or models created at the
Issue 04 | January 2025
start often go outdated as the site progresses, which may risk inaccurate UGV inspections,” explains Dr Yeoh.
“There’s also the challenge of aligning the UGV’s view with digital plans, or BIM, in real time. It’s like moving through a maze that’s always changing, where the map and the actual layout don’t always match.”
“There’s also the challenge of aligning the UGV’s view with digital plans, or BIM, in real time. It’s like moving through a maze that’s always changing, where the map and the actual layout don’t always match. Without precise alignment, these robots risk overlooking important site details or misinterpreting data,” he adds.
Dr Yeoh’s team developed two complementary measures tailored to the demands of indoor construction sites. The first approach involves a premapping method that uses video footage taken earlier in the construction process to create an accurate, updated map. Construction sites often have temporary objects — tools, scattered materials or debris — that appear during recording but may not be present when the UGV is deployed. The team’s method analyses this footage to pinpoint and remove such transient objects.
“This essentially ‘cleans’ the map, weeding out clutter and irrelevant data to give UGVs a clear navigation route,” adds Dr Yeoh. “By creating the map offsite, we also minimise disruption to ongoing construction, which can help foster greater acceptance of UGVs on site.”
While premapping optimises navigation, the second approach addresses an equally critical need: ensuring that UGVs can precisely match their on-site views with digital models, such as BIM. Misalignment could cause UGVs to miss important details — like a wall that is slightly out of place, or an electrical outlet installed erroneously. To prevent such oversights, Dr Yeoh’s team designed a sequential rectification process that continuously compares the UGV’s view with BIM data, prompting small adjustments to correct positioning and angle. In featureless areas, like long and uniform hallways, geometric markers help fine-tune the robot’s orientation.
“With accurate real-time alignment, UGVs enable construction managers to perform quality checks without relying on manual inspections,” adds Dr Yeoh.
Paving a way forward for construction site robots
Improving UGV navigation and functionality on construction sites is an important first step towards achieving a fully autonomous robotic workforce — one that is not just efficient and accurate but also capable of making more effective decisions. “The biggest benefit would be enhanced safety in site operations, particularly for hazardous tasks,” adds Dr Yeoh. “These advancements will also improve the reliability and consistency of how robots perform their tasks. With this, project owners may then see significant returns on investment, encouraging broader adoption and acceptance over time.”
“The biggest benefit would be enhanced safety in site operations, particularly for hazardous tasks.”
The research team has already identified areas for further improvement. They aim to improve the efficiency of the alignment method in heavily cluttered spaces. They also plan to integrate the approach into a real-time simultaneous localisation and mapping framework, which would enable UGVs to continuously adjust their position and maintain alignment with BIM models as they move through the site.
As robots find their bearings, smart navigation may soon be the new foundation for progress at construction sites.