Reliable operation of adjustable ballast systems is essential for full-ocean-depth manned submersibles, but existing studies mostly focus on component-level performance optimization, leaving the multi-valve coupled instability mechanism under ultra-high pressure insufficiently understood. This paper investigates an uncontrolled water injection failure in the adjustable ballast system of the “Fendouzhe” submersible via fault tr...

With the advancement of deep-sea exploration, the demand for underwater manipulators capable of long-duration heavy-duty operations has intensified. Water-hydraulic systems exhibit less viscosity variation with increasing depth than oil-based systems, offering better adaptability to deep-sea conditions. Using seawater as the driving medium inherently eliminates issues such as oil contamination by water, frequent maintenance li...