An earthworm-inspired, self-propelled robotic sleeve designed for installing underground power lines has been developed by a team of researchers at Case Western Reserve University.

Much like earthworms, which move by contracting their body segments in a wave-like motion, the new robot employs a mechanism of alternating segment expansion and retraction to achieve locomotion.

Source: Case Western Reserve UniversitySource: Case Western Reserve University

The developers explained that the robot’s body is divided into different sections that work in opposition with certain sections expanding outward and anchoring against the surrounding environment while others retract and pull the robot forward, thus producing a synchronized, wave-like movement that replicates an earthworm’s peristalsis.

Because the robot can precisely anchor itself, the researchers believe that this will minimize the risk of impacts and damage to delicate infrastructure like underground pipes associated with horizontal directional drilling (HDD), which tends to be costly, disruptive and potentially damaging to underground infrastructure.

The team explained: “We use actuators to change the length and diameter of each segment. The short and fat segments press against the walls of the burrow, then they anchor so the thin segments can advance forward. If two segments aren’t touching the ground but they’re changing length at the same time, your anchors don’t slip and you advance forward.”

While the HDD relies on a straightforward and forceful method of pushing a drill head through the soil, it encounters increasing resistance as the bore length extends, which requires greater and greater force. Conversely, the earthworm-inspired drilling concept reportedly produces the force necessary for the tip from the peristaltic segments within the borehole.

As such, the operators are able to maintain control, and if they meet an obstruction, they can reverse, redirect and readjust the robot’s depth to resume the burrowing process.

Further, the new peristaltic robot also streamlines the process of conduit installation. The team explained that as the robot moves through the soil, it simultaneously lays the conduit, thereby marrying the drilling and installation phases.

Such technology promises to reduce undergrounding costs, installation times and above-ground traffic disruptions, the researchers concluded.

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