Walls are surmountable obstacles by design. A barrier between what is in and what is out needs some way to be permeable, when the finite contents of what is inside a wall is not enough to sustain the people relying on it. The most common way to permeate a wall is a gate or a door, controlled by defenders, but ladders, too, can provide access beyond the control of gatehouse guards. Which is especially relevant now, because not only can humans climb walls, but new robots can, too.

Developed by Tokyo Metropolitan University, this robot is a quadruped that transitions from horizontal movement on four legs to climb vertically by gripping the rungs of a ladder. It is a slower, more deliberate process than one might imagine, with machine vision processing space and gripper arms slowly finding their hold.

It is perhaps all the more haunting that it is so slow. If it were an animated achievement, a work of cinematic fiction, the robot would be effortless, a comfortable distance from reality.

Instead, this robot dog climbs a ladder like a sloth climbs a tree, slow limb after slow limb pulling its bulk into place. Even sped up, the climbing process in the video drags on and on. Such in the nature of a proof-of-concept, a slow shambling movement with hints of future potential.

The robot research was presented at the 2019 IEEE/RSJ International Conference on Intelligent Robots and Systems. Published as “A Novel Capability of Quadruped Robot Moving Through Vertical Ladder Without Handrail Support,” a glimpse of the results can be found at IEEE Spectrum.

The ways humans can use a robot dog that climbs ladders is limited, broadly, to the number of spaces one can imagine moving on both feet and ladders, plus the ultimate speed of the robot. Moving through built spaces rendered unsafe for humans, like damaged nuclear power plants, say, or a ship on fire, is a more obvious use case.

Mounting sensors or gear on the robot, it could provide resupply up vertical distances, so long as the ladder it’s using can support its weight limit.

Applied to the same advances as other robotic dog-like squadmates, a robot could accompany assaults or explorations over walls at the behest of human guides. A wall may be an ancient form of defense, but the sight of a robot dog climbing a ladder over a wall, and then barreling down on the defenders behind it, is an undeniably modern phenomena.

Watch the robot in action below: