Mo Xiaojuan, Romano Donato, Milazzo Mario, Benelli Giovanni, Ge Wenjie, Stefanini Cesare
School of Mechanical Engineering, Northwestern Polytechnical University, 710072 Xi'an, China.
The BioRobotics Institute, Sant'Anna School of Advanced Studies, 56025 Pisa, Italy.
Appl Bionics Biomech. 2020 Mar 19;2020:2797486. doi: 10.1155/2020/2797486. eCollection 2020.
Ontogenetic locomotion research focuses on the evolution of locomotion behavior in different developmental stages of a species. Unlike vertebrates, ontogenetic locomotion in invertebrates is poorly investigated. Locusts represent an outstanding biological model to study this issue. They are hemimetabolous insects and have similar aspects and behaviors in different instars. This research is aimed at studying the jumping performance of over different developmental instars. Jumps of third instar, fourth instar, and adult . were recorded through a high-speed camera. Data were analyzed to develop a simplified biomechanical model of the insect: the elastic joint of locust hind legs was simplified as a torsional spring located at the femur-tibiae joint as a semilunar process and based on an energetic approach involving both locomotion and geometrical data. A simplified mathematical model evaluated the performances of each tested jump. Results showed that longer hind leg length, higher elastic parameter, and longer takeoff time synergistically contribute to a greater velocity and energy storing/releasing in adult locusts, if compared to young instars; at the same time, they compensate possible decreases of the acceleration due to the mass increase. This finding also gives insights for advanced bioinspired jumping robot design.
个体发育过程中的运动研究聚焦于一个物种不同发育阶段运动行为的演变。与脊椎动物不同，无脊椎动物个体发育过程中的运动情况鲜有研究。蝗虫是研究这一问题的出色生物学模型。它们是渐变态昆虫，在不同龄期具有相似的特征和行为。本研究旨在探究蝗虫在不同发育龄期的跳跃性能。通过高速摄像机记录三龄、四龄和成虫期蝗虫的跳跃。对数据进行分析以建立该昆虫的简化生物力学模型：蝗虫后腿的弹性关节被简化为位于股骨 - 胫骨关节处的扭簧，该关节有一个半月形突起，且基于涉及运动和几何数据的能量方法。一个简化的数学模型评估了每次测试跳跃的性能。结果表明，与幼虫期相比，成虫期蝗虫后腿长度更长、弹性参数更高以及起跳时间更长，协同作用导致更高的速度和更大的能量储存/释放；同时，它们补偿了由于质量增加可能导致的加速度下降。这一发现也为先进的仿生跳跃机器人设计提供了思路。
