A robotically built dry-stone wall

Researchers at ETH Zürich taught an autonomous excavator to construct dry stone walls by itself, using demolition debris and boulders weighing several tonnes.

The construction of dry stone walls generally involves a lot of manual labour, but this changes with the new robot. The autonomous excavator called HEAP uses sensors to draw a 3D map of the construction site and localise existing building blocks and stones for the wall’s construction, which it can also pick up and approximate their weight as well as the centre of their gravity. An algorithm determines the best position for each stone, and the excavator then conducts the task itself by placing the stones in the desired location. The autonomous machine can place 20 to 30 stones in a single consignment – about as many as one delivery could supply.

Using this technology, the excavator build a loadbearing wall of six metre high and sixty five metre long, using large boulders of several tonnes, as well as reclaimed pieces of concrete from demolition debris. This potentially could save a lot of CO2 emissions, if locally available stones and debris is used in the construction of dry-stone walls.

Images: ETH Zurich / Marc Schneider