Rotorcraft Rotor Speed Regulation via Ground-State Detection

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Solution Overview

Problem

Existing rotorcraft systems lack an effective solution for automatically regulating main rotor speed during ground movements, such as taxiing, which leads to noise pollution issues before take-off or after landing, affecting operator and passenger comfort.

Innovation Solution

A device and method that automatically control the main rotor speed by detecting the rotorcraft's ground or flight state using sensors and a control setpoint, allowing for two predetermined speeds: a lower speed for ground operations and a nominal speed for flight, with additional thresholds for static or high-speed maneuvers, and incorporating verification and calculation steps to prevent errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the main rotor speed is maintained at nominal speed NR1 during ground operations, then the rotorcraft has sufficient power availability for immediate take-off, but noise pollution increases and operator/passenger comfort deteriorates

Engineering Contradiction:
Improvenoise pollutionVSAvoidpower availability
Core Design Contradiction:
Object-affected harmful factorsVSPower

Solution Approach 1:

The system dynamically adjusts the main rotor speed based on the rotorcraft's operational state (ground vs flight). Detection means identify whether the rotorcraft is on the ground or in flight, and the management means automatically select between a reduced speed NR2 for ground operations and nominal speed NR1 for flight, enabling the system to adapt its performance characteristics to current operational requirements

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the operational parameter of main rotor speed from a fixed nominal value to a variable parameter that automatically takes different values (NR1 or NR2) based on detected operational conditions. This parameter change allows the system to optimize noise levels during ground operations while maintaining power availability when needed

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If the main rotor speed is reduced to optimize noise levels during ground operations, then noise pollution decreases, but the complexity of the control system increases due to multiple speed thresholds and state detection requirements

Engineering Contradiction:
Improvenoise pollutionVSAvoidcontrol system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The control system is segmented into distinct functional modules: detection means for identifying operational state, management means for speed regulation, and verification means for safety checks. This segmentation allows each module to perform its specific function independently, making the overall complex system more manageable and maintainable

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system incorporates feedback through detection means that continuously monitor the rotorcraft's operational state and feed this information back to the management means. This feedback loop enables automatic adjustment of rotor speed based on current conditions, reducing the need for manual intervention and simplifying operation despite the underlying complexity

Inventive Principle:
Principle #23Feedback

3Ease of operation

If automatic speed regulation is implemented during ground movements, then operator comfort and noise levels improve, but the risk of regulation errors increases without verification mechanisms

Engineering Contradiction:
Improveoperator comfortVSAvoidregulation accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The verification means perform preliminary checks before the management means execute speed regulation commands. By verifying detection results and regulatory decisions in advance, the system prevents erroneous regulation actions, ensuring that automatic speed adjustment only occurs when conditions are properly confirmed

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The verification means act as a protective layer that cushions against potential regulation errors. This preliminary verification step provides a safety buffer that prevents incorrect speed adjustments, thereby maintaining reliability while still enabling automatic regulation for operator comfort

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP3147212B1A device for regulating the speed of rotation of a rotorcraft rotor, a rotorcraft fitted with such a device, and an associated regulation method
Publication Date: 2018.03.21 EUROCOPTER FRANCE SA
  • EP3147212B1 patent drawingFigure 1~2
  • EP3147212B1 patent drawingFigure 3
  • EP3147212B1 patent drawingFigure 4

AI summary

The present invention relates to a device for regulating the rotational speed (1), referred to as NR speed, of at least one main rotor (2) of a rotorcraft (3). Such a rotorcraft (3) comprises: • at least one manual flight control element (4) for providing a control command C for the collective pitch of the blades (5) of said at least one main rotor (2), said control command C being a function of a current position of said at least one control element (4), and • detection means (8) for detecting a current state among at least two distinct states of said rotorcraft (3), namely a "ground" state in which said rotorcraft (3) is in at least partial contact with the ground (6) and a "flight" state in which said rotorcraft (3) is at least in suspension in the air (7).