Rotor Sail Thrust Control Using Wind-Responsive Blade Rotation

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Solution Overview

Problem

Existing sailing ships with vertical blades and propellers lack the ability to adjust propulsive force effectively.

Innovation Solution

A rotor sail system with a vertical support post, blades rotatable about a shaft, a detection unit for wind direction and speed, and a rotation control unit to adjust the blade's rotational speed based on thrust commands, along with features like brake units and energy storage for regenerative energy, allowing precise control of propulsive force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the blade is allowed to rotate freely to generate propulsive force from wind, then the ship can utilize wind power for propulsion, but the propulsive force cannot be adjusted

Engineering Contradiction:
Improvewind power utilizationVSAvoidpropulsive force adjustability
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by transitioning from a static free-rotation system to a dynamically controllable system. The rotation control unit actively manages blade rotational speed based on detected wind conditions and thrust commands, enabling the system to adapt its propulsive output dynamically rather than operating passively at fixed rotational speeds.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameter of rotational speed from an uncontrolled variable to a controlled parameter. By adjusting the rotational speed of the blade according to wind direction, wind speed, and desired thrust, the system can modulate propulsive force to match varying operational requirements while maintaining efficient wind energy conversion.

Inventive Principle:
Principle #35Parameter changes

2Force

If the rotational speed of the blade is increased to generate more thrust, then the propulsive force increases, but the system becomes more complex requiring control mechanisms

Engineering Contradiction:
ImprovethrustVSAvoidcontrol system complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The rotation control unit serves multiple functions: it detects wind conditions, processes thrust commands, determines optimal rotational speeds, and actuates the blade rotation control. This multi-functional approach consolidates what could be separate complex subsystems into a single integrated control unit, increasing thrust capability while minimizing the addition of separate control mechanisms.

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

Solution Approach 2:

The system implements feedback control where the rotation control unit continuously monitors wind direction and wind speed, compares the actual thrust against the commanded thrust, and adjusts blade rotational speed accordingly. This closed-loop feedback mechanism enables precise thrust control without requiring overly complex open-loop control systems with multiple actuators and sensors.

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

The system enables adjustable propulsive force by controlling blade rotation according to wind conditions, enhancing propulsion efficiency and safety in varying wind speeds.

Implementation Method 1

a blade (10A to 10F) connected to a shaft (5) and rotating about the shaft (5); a detection unit (7) detecting a wind direction and a wind speed

Methodology Applied
Scientific EffectWind power: Wind Power

Implementation Method 2

the rotation control unit (40) includes an electric motor (41) capable of rotationally driving the shaft (5)

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 3

an energy storage unit (46) storing regenerative energy generated by the electric motor (41) when the rotation of the shaft (5) decelerates

Methodology Applied
Scientific EffectRegenerative braking: Electromagnetic Induction

Data Source

PatentEP4722100A1Windmill sail system and ship integrated propulsion system
Publication Date: 2026.04.08 NABTESCO CORP
  • EP4722100A1 patent drawingFigure 1
  • EP4722100A1 patent drawingFigure 2
  • EP4722100A1 patent drawingFigure 3

AI summary

A rotor sail system includes: a vertical support post extending in a vertical direction from a hull; a blade connected to a shaft, the blade being rotatable about the shaft, the shaft extending in a predetermined direction with reference to the vertical support post; a detection unit detecting a wind direction and a wind speed in a navigation area of a ship; a receiving unit receiving a thrust command to specify a thrust of the ship; and a rotation control unit capable of controlling a rotational speed of the blade about the shaft. The rotation control unit controls the rotational speed of the blade about the shaft based on the received thrust command and a detection result of the wind direction and the wind speed detected when the thrust command is received.