This impressive arm robot figures out how best to stack oddly shaped rocks

Remember those mysterious piles of rocks left outside the kids’ tents in The Blair Witch Project? It seems that we might have been barking up the wrong tree with supernatural explanations because, as it turns out, it may have been robots after all!

At least, that’s if the folks at ETH Zurich had anything to do with it. At this week’s ICRA 2017 event in Singapore, the Swiss researchers showed off a robot that is designed to autonomously stack pieces of limestone into balanced towers.

While that is the kind of thing that a human child may be able to do, it is a tough ask for a robot due to the planning involved — not to mention the odd shape of the irregular rocks it is being asked to manipulate. To handle this, the researchers each took charge of a different operation the robot had to carry out: Either object detection, object manipulation, or a pose-searching algorithm that works out how best to stack the rocks based on what it knows about previous rock stacks.

The researchers do, admittedly, cheat a little bit. Sure, each rock is different, but the robot has 3D scanned them in advance of its building task, thereby letting it carry out simulations before starting work on the actual physical stacking. That does not make its achievement any less impressive, though. While kids can, as mentioned, create stacks of a few rocks without too much trouble, the ability to heap six on top of one another is something that is a bit trickier than it looks.

In all, the work represents an exciting step forward in what its creators hope will one day be the ability of robots to use local building materials to create structures — or, at the very least, carry out a spot of landscape gardening.

You can check out the authors’ paper, titled “Autonomous Robotic Stone Stacking with Online next Best Object Target Pose Planning,” here.