Drop-Weight Buoyancy System for Pump-Free Underwater Gliders

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Solution Overview

Problem

Existing underwater gliders rely on noisy and energy-consuming hydraulic pumps for buoyancy control, limiting their operational efficiency and longevity.

Innovation Solution

A pump-less buoyancy system using prepackaged weights and buoyant compartments to adjust buoyancy and center of gravity, employing weight release and buoyancy changes without hydraulic pumps, allowing for efficient vertical movement and forward propulsion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If hydraulic pumps are used for buoyancy control, then buoyancy adjustment capability is achieved, but noise level and energy consumption increase

Engineering Contradiction:
Improvebuoyancy control capabilityVSAvoidnoise level
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent removes the hydraulic pump system entirely from the underwater glider, extracting the noisy and energy-consuming component while replacing it with a passive buoyancy control mechanism using prepackaged weights and buoyant compartments that adjust buoyancy through weight release rather than active pumping

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the active mechanical hydraulic pump system with a passive mechanical system based on gravity and buoyancy forces, where prepackaged weights are released to change the glider's overall density and buoyancy state without requiring any powered mechanical components

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If hydraulic pumps are used for buoyancy control, then buoyancy adjustment capability is achieved, but energy consumption increases

Engineering Contradiction:
Improvebuoyancy control capabilityVSAvoidenergy consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent removes the hydraulic pump system entirely from the underwater glider, extracting the noisy and energy-consuming component while replacing it with a passive buoyancy control mechanism using prepackaged weights and buoyant compartments that adjust buoyancy through weight release rather than active pumping

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The buoyancy control system operates autonomously using passive physical principles - gravity pulls the released weights downward while buoyant compartments provide upward force, eliminating the need for external energy input to control buoyancy transitions

Inventive Principle:
Principle #25Self-service

3Object-generated harmful factors

If prepackaged weights are released to adjust buoyancy, then noise level decreases, but device complexity increases

Engineering Contradiction:
Improvenoise levelVSAvoidbuoyancy system complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The buoyancy control system is segmented into discrete prepackaged weight units and separate buoyant compartments, allowing independent control of weight release and buoyancy adjustment through modular components rather than a monolithic hydraulic system

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances operational duration and speed by reducing noise and energy consumption, enabling longer missions and increased stealth capabilities.

Implementation Method 1

The drop weight system is used to reduce the vehicle's weight to alter its density. As a result, the vehicle can ascend in the water

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

The change in the vehicle's total volume alters its buoyancy, making it move upward or sink as required

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 3

It utilizes the flow of fluid, in this case water, over a set of wings to generate lift and thrust

Methodology Applied
Scientific EffectLift generation: Aerofoil

Data Source

PatentEP4380856B1Drop weight buoyancy system for underwater gliders
Publication Date: 2025.10.08 RTX BBN TECH INC
  • EP4380856B1 patent drawingFigure 1
  • EP4380856B1 patent drawingFigure 2A~2E
  • EP4380856B1 patent drawingFigure 3A~3B

AI summary

A pump-less buoyancy engine for an autonomous underwater vehicle (AUV) includes a buoyancy reduction structure (302) without a hydraulic pump for reducing the buoyancy of the AUV to cause the AUV to descend in the water; and a weight dropping structure for dropping prepackaged weights out of the AUV to cause the AUV to ascend in the water, where the AUV moves forward when descending and ascending.