An autonomous underwater glider serving large spatiotemporal monitoring in hadal zones

Hadal zones are immensely difficult to explore due to their incredibly harsh environments. In this study, an autonomous underwater glider called Petrel-XPLUS was developed for monitoring hadal zones at large spatiotemporal scales. This glider is equipped with a bionic gradient functional housing, the multi-material pressure housing, to cope with the coupled effects of extremely high pressure and density variations, endowing it with light weight, near-neutral buoyancy, and sufficient onboard energy. Furthermore, an innovative dual-eccentric attitude-regulating mechanism is proposed to increase the pitch angle range from [−45°, 45°] to [−90°, 90°] and enrich four types of glider motion modes. This mechanism and a depth-averaged flow-based path planning method enable the glider to handle the superimposed effects of unknown currents and complex topography for effective access to the hadal zone floor. The developed glider has an operating range of 5000 km or 80 dives to a depth of 11,000 m in a single mission lasting 200 d. Petrel-XPLUS successfully completed three dives exceeding 10,000 m with a maximum depth of 10,619 m and an average station-keeping accuracy of 2.018 km during a sea trial in the Mariana Trench. Our study provides a novel technical reference for facilitating hadal exploration.