Researchers at RTH Zurich have trained a modified excavator to build a 215-foot-long stone retaining wall in Switzerland.
The 12-ton Menzi Muck M545, known as HEAP, or "hydraulic excavator for an autonomous purpose," was equipped with satellite navigation, inertial measurement, joint angle sensors and multiple cabin- and arm-mounted LiDAR sensors and cameras to map the site and scan the building materials.
(To watch the M545 in action, check out the video at the end of this story.)
Each stone was individually picked up, laser-scanned by the excavator’s grapple, placed back on the ground for storage and saved in the excavator’s inventory to later match to a spot on the wall. As the stones were placed on the wall, the excavator rescanned them and updated its geometric planner.
Researchers say this process was repeated each time after all scanned stones were placed or after the planner was no longer able to find solutions with the available inventory. The final wall consisted of 938 unique elements, with a mixture of reclaimed concrete, mixed erratics and gneiss boulders.
Because the test took place on an active construction site, a human operator remained in the cab to provide oversight and avoid accidents. The scanning, picking and placing were performed autonomously while the operator assisted with driving between operations.
