Design Optimization of an Ultrafast-Striking Mantis Shrimp Microrobot

Abstract

Mantis shrimp produce one of the fastest strikes in the animal kingdom, their striking appendages reaching tip velocities of tens of meters per second underwater. Their ultrafast movement is capable of crushing the shells of prey and generating cavitation bubbles, and has long raised interest from the scientific community. To study the underlying mechanisms and operating principles behind these behaviors, prior research has developed physical models that mimic the motions and speeds of mantis shrimp. That microrobot demonstrated speeds of approximately 5 m/s in water and 26 m/s in air. Here we utilize an accurate dynamical model of the four-bar mechanism and geometric latch observed in biological shrimp in a numerical trajectory optimization approach to find the design changes that can maximize the microrobot's striking velocities. Through a suboptimization problem maximizing the energy loaded in the mechanism's spring, we manage to improve the performance of the microrobot by over 58%, reaching tip velocities of 41.2 \pm 0.641.2 \pm 0.6 m/s.