Dry stone walls are a timeless symbol of human ingenuity and have stood the test of time. Their history spans back to ancient times with some of the earliest examples carbon dated back to 3500 BCE. Remarkably, many of these walls still exist, a testament to their durability and the skill of their creators. These walls, constructed without cement, rely on gravity and friction for stability.
Mankind started to discover ways of binding bricks with materials such as mud; straw; gypsum and lime and the construction of the Great Pyramid at Giza used a type of mortar. This was around 2500 BCE.
Despite the continued refinement of binding agents, dry stone wall structures continued to be built around the world due to their simplicity and durability. Binding agents were not universally available and were still being refined. It was not until 1824, when Joseph Aspdin patented Portland Cement, that a consistent and universal product was available to use in construction.
Fast forward to today and there are still structures being made with the ancient methodology of dry stone walling. It is a task that requires high levels of skills and is plain hard work. There are very few people in the world that are designated as "masters" in the craft of dry stone walling and these people are in high demand globally.
Enter the realm of technology, where a new concept is poised to revolutionise this ancient craft: an autonomous robot capable of constructing dry stone walls. This innovative robot, a brainchild of researchers at ETH Zurich, Switzerland, signifies a groundbreaking (sorry for that pun) advancement in construction technology.
This robotic excavator, equipped with 3D digital mapping and artificial intelligence (AI), can autonomously build massive stone walls. It selects and scans each boulder to determine its optimal placement in a wall. The robot has already demonstrated its capabilities by constructing a six-metre high, 65-metre long stone wall in a public park in Zurich.
The key to this robot's functionality lies in its sophisticated technology. Equipped with lidar, which uses lasers to measure distances, the robot creates its own 3D map of the construction site.
AI models then assist in determining the best way to grasp and place individual stones. Once the robot identifies a stone based on the digital map, it scans it to determine the best fit for the wall.
The current rate of stone placement by the robot is one every 12 minutes, slightly slower than experienced human operators. Despite being marginally slower, it does have one advantage over humans: no breaks needed to sleep and eat.
The robot's digital mapping and AI analysis allows for nearly perfect placement with each stone, with a median positional error of only 10 centimetres. A human supervisor oversees the operation and the robot is manually driven between locations on the construction site.
The development of this robotic technology signifies a significant shift in construction methodologies.
By automating the process of building dry stone walls, this technology could help preserve this ancient craft while addressing the shortage of skilled craftsmen.
Moreover, it demonstrates the potential of AI and robotics in undertaking complex, skilled tasks that were previously thought to be the exclusive domain of human artisans.
As this technology evolves, the researchers aim to enhance the robot's autonomy, enabling it to operate safely and efficiently alongside human workers.
The future of construction, particularly in specialised areas like dry stone wall building, is poised to be transformed by these advancements in robotics and AI.