Morphological intelligence in desert locust and dynamic robots

Tinuku - Animals in natural environments necessarily come into contact with surfaces having differing orientations and materials. However, not much is known about how their feet contribute to friction, particularly in the case of dual-attachment mechanisms and passive mechanics (morphological intelligence).

The researchers of the Physical Intelligence Department of the Max Planck Institute for Intelligent Systems at Stuttgart study the desert locust’s (Schistocerca gregaria) morphology, spines and adhesive pads, and jumping behavior to extract traits that contribute to enhancing friction.

Tinuku Morphological intelligence in desert locust and dynamic robots

“Our results demonstrate the potential contribution of morphological intelligence to solving complex dynamic locomotion problems. We anticipate that this study will inspire further research of the strategies used by animals to interact dynamically with diverse surfaces,” said Matthew Woodward and Metin Sitti.

During dynamic terrestrial locomotion, animals use complex multifunctional feet to extract friction from the environment. However, whether roboticists assume sufficient surface friction for locomotion or actively compensate for slipping, they use relatively simple point-contact feet.

Woodward and Metin Sitti seek to understand and extract the morphological adaptations of animal feet that contribute to enhancing friction on diverse surfaces, such as the desert locust, which has both wet adhesive pads and spines. Therefore, all surface adaptation must be through passive mechanics, which are unknown

A buckling region in their knee to accommodate slipping, slow nerve conduction velocity (0.5–3 m/s), and an ecological pressure to enhance jumping performance for survival further suggest that the locust operates near the limits of its surface friction, but without sufficient time to actively control its feet.

“Here, we report the slipping behavior, dynamic attachment, passive mechanics, and interplay between the spines and adhesive pads, studied through both biological and robotic experiments, which contribute to the locust’s ability to jump robustly from diverse surfaces,” said the researchers.

Slipping to be surface-dependent and common (e.g., wood 1.32 ± 1.19 slips per jump), yet the morphological intelligence of the feet produces a significant chance to reengage the surface (e.g., wood 1.10 ± 1.13 reengagements per jump). Additionally, a discovered noncontact-type jump, further studied robotically, broadens the applicability of the morphological adaptations to both static and dynamic attachment.

Furthermore, the concepts presented can be easily adapted to, for the enhancement of, existing simple miniature and state-of-the-art large-legged terrestrial robots. The team reported to Proceedings of the National Academy of Sciences.