Marine Thruster Vectoring for Low-Speed Maneuvering

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Solution Overview

Problem

Conventional propulsion methods for underwater vehicles face challenges in maneuvering efficiently and stably at low speeds due to the reliance on fluid flow for control surface lift and drag, which decreases efficiency and increases energy consumption.

Innovation Solution

A method for piloting a marine vehicle with two propellers, where each propeller generates a flow directed towards and reaching the flow generated by the other propeller, allowing for stable and efficient maneuvering by controlling the combined thrust force to have a non-zero radial component, enabling movement at zero speed and precise control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional propulsion with control surfaces is used, then vehicle steering is achieved through fluid flow, but efficiency decreases inversely with the square of flow velocity and energy consumption increases

Engineering Contradiction:
Improvevehicle steering capabilityVSAvoidenergy consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

Instead of using control surfaces that require fluid flow to generate lift for steering, the patent inverts the approach by using propellers to directly generate thrust vectors for steering. The twin propellers can be independently controlled to produce differential thrust, enabling steering without relying on fluid flow over control surfaces, thus eliminating the efficiency degradation at low speeds and reducing energy consumption.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts and eliminates the control surfaces (rudders, elevators) from the conventional propulsion system. By removing these surfaces that require significant fluid flow to function, the system achieves steering capability through propeller thrust vectoring alone, resolving the contradiction between steering ease and energy consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If control surfaces are used for maneuvering, then vehicle direction is changed, but hydrodynamic drag increases proportionally to the square of speed

Engineering Contradiction:
Improvemaneuvering capabilityVSAvoidhydrodynamic drag
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes control surfaces from the vehicle architecture, replacing them with a twin propeller system that provides maneuvering capability through differential thrust. This extraction eliminates the source of hydrodynamic drag associated with control surfaces while maintaining full maneuvering versatility through vector propulsion.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The twin propeller system serves multiple functions: primary propulsion, steering, and maneuvering. By making the propellers universal components that can perform all these functions through independent speed and pitch control, the patent eliminates the need for separate control surfaces, thereby reducing hydrodynamic drag while maintaining adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If twin propellers are used for vector propulsion, then mobility is increased and architecture is simplified, but control difficulties arise particularly at low speed

Engineering Contradiction:
ImprovemobilityVSAvoidcontrol stability
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent implements feedback control mechanisms to monitor and adjust propeller speeds and pitches in real-time, particularly at low speeds where control stability is challenging. This feedback system ensures that the twin propellers maintain stable and predictable thrust vectors, resolving the control difficulties while preserving the mobility advantages of vector propulsion.

Inventive Principle:
Principle #23Feedback

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

This approach allows for stable and efficient maneuvering of underwater vehicles at low speeds, reducing energy consumption and eliminating the need for additional maneuvering systems, thereby enhancing mobility and control without generating hydrodynamic drag.

Implementation Method 1

each propeller generates a flow directed towards and reaching the flow generated by the other propeller

Methodology Applied
Scientific EffectFluid flow generation:

Data Source

PatentEP3393903B1System and method for marine vehicle thruster control
Publication Date: 2021.11.10 THALES SA
  • EP3393903B1 patent drawingFigure 1~2
  • EP3393903B1 patent drawingFigure 3~4
  • EP3393903B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for controlling a thruster of a marine vehicle (1) that is at least partially submerged in a liquid and includes a body (2) and a thruster (3) that includes two propellers (AV, AR). Each propeller includes blades intended to turn about an axis of rotation of said propeller. The method includes a low-speed maneuver control step, during which the thruster is controlled such that each propeller (AV, AR) generates a flow directed toward and reaching the flow generated by the other propeller.