Robot locomotion via caterpillar motion

A Tufts University neurobiologist is conducting research on caterpillar locomotion. The results could pave the way for the design of flexible robots capable of exploring internal human organs.

Tufts University neurobiologist Barry Trimmer is inching his way to unlocking the secrets behind the way caterpillars manoeuvre and climb, and is using that knowledge to one day build flexible robots that could explore internal organs, blood vessels and the insides of pipelines.

“We are trying to understand how the nervous system controls these complex movements so we can replicate that movement and build our own soft-bodied robots that manoeuvre easily, like a caterpillar,” Trimmer said.

He added, “Our research has potential applications in the design and control of a new type of flexible robot that could be used to navigate through pipelines or intricate structures such as blood vessels and air tubes, as well as space shuttle operations and building construction.”

Trimmer’s lab is believed to be the only one of its kind to focus on the locomotion of soft-bodied insects, specifically the nervous system and how it works with the biomechanics of the caterpillar.

Two specific aspects of the caterpillar’s movement are being examined in detail: first, the research is trying to understand how crawling is controlled by the central nervous system and how it interacts with peripheral structures such as muscles and cuticles. Second, the unique ability of caterpillars to climb using curved hooks at the tips of the abdominal prolegs is being examined. This gripping is passive but very strong and can be actively released.

To examine these questions, Trimmer and his research team are using 3D kinematics, electromyography, hydraulic measurements, magnetic resonance imaging, 3D modelling and animation and biomaterials testing.

Caterpillars provide a useful survival model in that they do not escape predators by running but instead use camouflage, chemical defences and cryptic behaviour. As a result, their crawling movement has evolved into a highly specialised form of locomotion which allows soft-bodied animals to crumple, compress and rotate body parts into confined three-dimensional structures such as tubes and branches.

This summer, the team will begin to design a computerised simulation model of the locomotion, and it hopes to have an operating prototype ready next year.

“We need to solve the artificial muscle problem first, currently there are no good soft actuators available,” according to Trimmer.

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