Click Beetles: Modeling Nature’s High-Power Mechanism for Small-Scale Robotics

Abstract

In the field of small-scale robotics, motion typically involves a tradeoff between strength and speed. However, many small animals are still capable of achieving extremely powerful motions using latch-mediated spring actuation (LaMSA). Such processes are often internal and difficult to study, but there is a widely-available exception: click beetles. These cosmopolitan beetles can jump without using legs or wings, through the actuation of a mechanism in the hinge between body segments. The objective of this work is to develop a biologically relevant robotic model organism (RMO) that characterizes this actuation mechanism, integrating morphologically accurate body segments with a LaMSA hinge developed by prior research at the Bio-inspired Adaptive Morphology Lab at Princeton University. This design enables controlled investigation of the mechanical principles governing loading and unlatching for click beetle LaMSA. Potential energy is stored through a combination of linear and torsional springs, while a geometric latch mediates release. The final system is actuated using an SMA actuator. Overall, this work presents an experimental framework for studying LaMSA systems through a robotic model. By bridging the gap between biology and engineering, the designed RMO enables isolated exploration of parameter spaces beyong those found in live click beetles. The insights gained from this study contribute to the design of high-power, small-scale robotic systems and advance understanding of the mechanical principles underlying LaMSA in both biological and engineered contexts.