Seals provided inspiration for a new waddling robot

It might be difficult to see at first, but if you squint just right, you can tell the latest animal-inspired robot owes its ungainly waddle to seals. Researchers at Chicago’s DePaul University looked at the movements of the aquatic mammal and its relatives for their new robot prototype—and while it may look a bit silly, the advances could one day help in extremely dire situations.

According to their paper’s abstract, the team writes they aimed to build a robot featuring “improved degrees of freedom, gait trajectory diversity, limb dexterity, and payload capabilities.” To do this, they studied the movements of pinnipeds—the technical term given to fin-footed mammals such as seals, walruses, and sea lions—as an alternative to existing quadrupedal and soft-limbed robots. Their final result is a simplified, three-limbed device that propels itself via undulating motions and is supported by a rigid “backbone” like those of their mammalian inspirations.

As also detailed last week via TechXplore, the robot’s soft limbs are each roughly 9.5 inches long by 1.5 inches wide, and encased in a protective outer casing. Each arm is driven by pneumatic actuators filled with liquid to obtain varying degrees of stiffness. Changing the limbs’ rigidness controls the robot’s directional abilities, something researchers say is generally missing from similar crawling machines.

Interestingly, the team realized that their pinniped product actually moves faster when walking “backwards.” While in reverse, the robot waddled at a solid 6.5 inches per second, compared to just 4.5 inches per second during forward motion. “Pinnipeds use peristaltic body movement to propel forward since the bulk of the body weight is distributed towards the back,” explains the team in its research paper. “But, the proposed soft robot design has a symmetric weight distribution and thus it is difficult to maintain stability while propelling forward. As a consequence, the robot shows limited frontal movements. Conversely, when propelling backward, the torque imbalance is countered by the body.”

But despite the reversal and slightly ungainly stride, the DePaul University team believes soft robots such as their seal-inspired creation could one day come in handy for dangerous tasks, including nuclear site inspections, search and rescue efforts, and even future planetary explorations. It might be one small step for robots, but it may prove one giant waddle for pinniped propulsion tech.