Salpot: A Jet Propulsion Swimmer With Scissor Structure and Bilateral Apertures

In recent years, researchers have increasingly turned to marine organisms for inspiration in designing underwater robots. While most robots rely on jet propulsion, akin to squid or jellyfish, using a single posterior aperture for water intake and expulsion, there are few incorporating an additional anterior aperture for water replenishment, similar to the salp. In this letter, we propose the Salpot, capable of filling water through bilateral apertures and swiftly compressing the chamber within its scissor structure to propel forward using only one motor. This design is considered advantageous for jet propulsion efficiency in biology and fluid dynamics. A series of experiments validated the mechanical design and swimming performance of Salpot, showing an approximate 10.5% improvement in CoT and an 18.2% increase in average velocity under the bilateral-aperture (salp-like) structure compared to the unilateral-aperture (squid-like) structure.