Design development and performance evaluation of a novel bistable metallic shells enabled underwater glider

Underwater gliders are renowned for their endurance to explore marine resources. However, their slower response and high energy consumption, stemming from slower, less efficient ballast systems, limit their application in shallow estuarine waters with complex conditions, e.g., uneven, rocky floors that require rapid depth adjustments. To overcome these limitations, we have pioneered a novel underwater glider powered by a bistable metallic shells-enabled ballast system that switches ballast states in just 0.82 s. The total volume change of the glider is equivalent to ±221g, with an ultra-fast ballast rate of ∼543 g/s. It consumes remarkably little power and has a very low cost of transport (∼0.057). We introduce an integrated system model that covers the design and performance of this glider and provides simulation results demonstrating its good stability at higher gliding velocities. The experimental results from preprogrammed trials at different glide paths validate these simulations. Its ultra-fast ballast rate and robustness are exhibited through experiments in a dive pool and a shallow lab pool. The field demonstration in the Pearl River Estuary validates the future potential of this glider, enabled by its ultra-fast ballast rate and low cost of transport, to conduct environmental and habitat monitoring in shallow, complex environments.