Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
Department of Physics, Harvey Mudd College, Claremont, CA 91711, USA.
J R Soc Interface. 2020 Jul;17(168):20200070. doi: 10.1098/rsif.2020.0070. Epub 2020 Jul 22.
The inherent force-velocity trade-off of muscles and motors can be overcome by instead loading and releasing energy in springs to power extreme movements. A key component of this paradigm is the latch that mediates the release of spring energy to power the motion. Latches have traditionally been considered as switches; they maintain spring compression in one state and allow the spring to release energy without constraint in the other. Using a mathematical model of a simplified contact latch, we reproduce this instantaneous release behaviour and also demonstrate that changing latch parameters (latch release velocity and radius) can reduce and delay the energy released by the spring. We identify a critical threshold between instantaneous and delayed release that depends on the latch, spring, and mass of the system. Systems with stiff springs and small mass can attain a wide range of output performance, including instantaneous behaviour, by changing latch release velocity. We validate this model in both a physical experiment as well as with data from the Dracula ant, , and propose that latch release velocity can be used in both engineering and biological systems to control energy output.
肌肉和马达的固有力量-速度权衡可以通过在弹簧中加载和释放能量来克服，从而为极端运动提供动力。这种模式的一个关键组成部分是闩锁，它调节弹簧能量的释放以驱动运动。闩锁传统上被认为是开关；它们将弹簧压缩保持在一个状态，并允许弹簧在另一个状态下不受限制地释放能量。使用简化接触闩锁的数学模型，我们再现了这种瞬时释放行为，并证明了改变闩锁参数（闩锁释放速度和半径）可以减少和延迟弹簧释放的能量。我们确定了一个关键的阈值，介于瞬时释放和延迟释放之间，该阈值取决于闩锁、弹簧和系统的质量。通过改变闩锁释放速度，具有刚性弹簧和小质量的系统可以实现广泛的输出性能，包括瞬时行为。我们在物理实验以及 Dracula 蚂蚁的数据中验证了这个模型，并提出闩锁释放速度可以在工程和生物系统中用于控制能量输出。
