The BioRobotics Institute, Scuola Superiore Sant'Anna, viale Rinaldo Piaggio 34, 56025, Pontedera, Italy.
J Exp Biol. 2013 Apr 1;216(Pt 7):1270-9. doi: 10.1242/jeb.076083.
Jumping insects develop accelerations that can greatly exceed gravitational acceleration. Although several species have been analysed using different tools, ranging from a purely physical to a morpho-physiological approach, instantaneous dynamic and kinematic data concerning the jumping motion are lacking. This is mainly due to the difficulty in observing in detail events that occur in a few milliseconds. In this study, the behaviour of the green leafhopper, Cicadella viridis, was investigated during the take-off phase of the jump, through high-speed video recordings (8000 frames s(-1)). We demonstrate that C. viridis is able to maintain fairly constant acceleration during overall leg elongation. The force exerted at the foot-ground interface is nearly constant and differs from the force expected from other typical motion models. A biomechanical model was used to highlight that this ability relies on the morphology of C. viridis hind legs, which act as a motion converter with a variable transmission ratio and use the time-dependent musculo-elastic force to generate a nearly constant thrust at the body-ground interface. This modulation mechanism minimizes the risk of breaking the substrate thanks to the absence of force peaks. The results of this study are of broad relevance in different research fields ranging from biomechanics to robotics.
跳跃昆虫的加速度可以大大超过重力加速度。虽然已经使用从纯物理到形态生理的不同工具对几种物种进行了分析，但有关跳跃运动的瞬时动态和运动学数据仍然缺乏。这主要是由于难以详细观察在几毫秒内发生的事件。在这项研究中，通过高速视频记录（8000 帧 s(-1))，研究了绿叶蝉在跳跃起飞阶段的行为。我们证明，绿叶蝉在整个腿部伸长过程中能够保持相当恒定的加速度。施加在脚与地面接触界面上的力几乎是恒定的，与其他典型运动模型所预期的力不同。生物力学模型表明，这种能力依赖于绿叶蝉后腿的形态，后腿作为一个运动转换器，具有可变的传动比，并利用时变的肌肉弹性力在身体与地面的接触界面上产生几乎恒定的推力。这种调制机制通过消除力峰值最小化了破坏基质的风险。这项研究的结果在从生物力学到机器人学的不同研究领域都具有广泛的意义。
