Body-catapult mechanism of the sandhopper jump and its biomimetic implications

Significance statement Jumping is a critical locomotion for an animal to successfully survive in nature. As one of the main jumping mechanisms, power amplification with catapult-like structure has been well studied in a few leg-driven jumping insects (e.g., locusts). However, less is known about the jump mechanism of some body-driven arthropods until now. Herein we quantitatively studied body-jumps of the sandhopper ( Talitrus saltator ) and its crucial catapult structures from the views of microstructure, composition and mechanical functions. Our results demonstrate that the arch-shaped structures at the fore margin of the posterior segments provide a large amount of power amplification ( > 80%). We anticipate this work will inspire some novel designs for bio-robots, especially for offering multi-segmented robots with excellent ability of jump through body-catapult mechanism. Power amplification with catapult-like structures in arthropods is well studied, including the jump mech-anism of natural organisms and biomimetic applications in robotics. Most catapult jump mechanisms have been developed based on animals that use legs to jump. However, jumps of some arthropods that use body parts other than legs and that show outstanding performance have been less studied until now. Here, we experimentally studied the jumping behavior of the sandhopper Talitrus saltator to determine whether they jump through the catapult mechanism and identify its critical catapult structures. The re-sults showed that the sandhopper jumps through a body-catapult mechanism (muscle-specific power output: 1.7-5.7 kW/kg, 3.4-11.4 times the power output limit of arthropod muscle). The arch-shaped structures at the fore margin of the five posterior segments can provide a large amount of strain en-ergy storage and account for more than 80% of the total kinetic energy demand. In addition, we build a biomimetic bi-segment device whose extension movement is actuated by sandhopper-inspired spring units. The results indicate that a multi-segmented robotic configuration can achieve rapid jumps based on the same principles of the body-catapult mechanism of the sandhopper. Significance statement Jumping is a critical locomotion for an animal to successfully survive in nature. As one of the main jumping mechanisms, power amplification with catapult-like structure has been well studied in a few leg-driven jumping insects (e.g., locusts). However, less is known about the jump mechanism of some body-driven arthropods until now. Herein we quantitatively stud-ied body-jumps of the sandhopper (Talitrus saltator) and its crucial catapult structures from the views of microstructure, composition and mechanical functions. Our results demonstrate that the arch-shaped structures at the fore margin of the posterior segments provide a large amount of power amplification ( > 80%). We anticipate this work will inspire some novel de-signs for bio-robots, especially for offering multi-segmented robots with excellent ability of jump through body-catapult mechanism. (c) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Power amplification with catapult-like structures in arthropods is well studied, including the jump mechanism of natural organisms and biomimetic applications in robotics. Most catapult jump mechanisms have been developed based on animals that use legs to jump. However, jumps of some arthropods that use body parts other than legs and that show outstanding performance have been less studied until now. Here, we experimentally studied the jumping behavior of the sandhopper Talitrus saltator to determine whether they jump through the catapult mechanism and identify its critical catapult structures. The results showed that the sandhopper jumps through a body-catapult mechanism (muscle-specific power output: 1.7?5.7 kW/kg, 3.4?11.4 times the power output limit of arthropod muscle). The arch-shaped structures at the fore margin of the five posterior segments can provide a large amount of strain energy storage and account for more than 80% of the total kinetic energy demand. In addition, we build a biomimetic bi-segment device whose extension movement is actuated by sandhopper-inspired spring units. The results indicate that a multi-segmented robotic configuration can achieve rapid jumps based on the same principles of the body-catapult mechanism of the sandhopper.

Automated summary

Power amplification with catapult-like structures in arthropods, including the jump mechanism of natural organisms and biomimetic applications in robotics, has been well studied. The study on body-jumps of the sandhopper Talitrus saltator revealed the crucial catapult structures providing significant power amplification, inspiring potential designs for multi-segmented bio-robots with excellent jumping ability.