Effect of Substrates' Compliance on the Jumping Mechanism of Locusta migratoria

Abstract

Locusts generally live and move in complex environments including different kind of substrates, ranging from compliant leaves to stiff branches. Since the contact force generates deformation of the substrate, a certain amount of energy is dissipated each time when locust jumps from a compliant substrate. In published researches, it is proven that only tree frogs are capable of recovering part of the energy that had been accumulated in the substrate as deformation energy in the initial pushing phase, just before leaving the ground. The jumping performances of adult Locusta migratoria on substrates of three different compliances demonstrate that locusts are able to adapt their jumping mode to the mechanical characteristics of the substrate. Recorded high speed videos illustrate the existence of deformed substrate's recoil before the end of the takeoff phase when locusts jump from compliant substrates, which indicates their ability of recovering part of energy from the substrate deformation. This adaptability is supposed to be related to the catapult mechanism adopted in locusts' jump thanks to their long hind legs and sticky tarsus. These findings improve the understanding of the jumping mechanism of locusts, as well as can be used to develop artifact outperforming current jumping robots in unstructured scenarios.

Influences of Different Drop Height Training on Lower Extremity Kinematics and Stiffness during Repetitive Drop Jump

“…Increased contact time results in increased knee flexion to absorb the increased landing force and thus greater jumping ability [ 7 , 31 ]. And the long contact time with the ground can follow the natural trend of the substrate recoil, thus wasting a minimum amount of energy [ 32 ]. In this study, jumping height increased gradually with drop height, which may have been caused by the jumping ability increasing with increasing contact time.…”

Jumping Locomotion Strategies: From Animals to Bioinspired Robots

“…Locusts' jumping dynamics is the most investigated among jumping animals [48,[79][80][81][82]. Locusts are endowed with three pairs of legs and wings.…”

“…For instance, substrates of different properties, like compliance and roughness levels, may hardly impact the jumping performances of animals and robots. While jumping animals have developed adaptative strategies to counteract eventual disadvantageous conditions of ground [80,81], most existing jumping robots lack in perception and adaptability.…”

Adapting small jumping robots to compliant environments

“…The energy available to the smaller systems studied in this work is typically limited to the energy initially stored in their springs and this energy is released over exceptionally fast time scales; jumps often occur over the span of milliseconds or less [9]. While our understanding of the biomechanics of LaMSA has recently advanced significantly [8,10–12], our understanding of how these jumpers interact with a non-rigid substrate is limited to observational studies [13–16]. In one recently studied example, Cuban tree frogs have been shown to recover some elastic energy back from compliant substrates [14,15].…”