Rotorcraft Vibration Adjustment Using Neural Network

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Solution Overview

Problem

Existing methods for adjusting rotorcraft rotors do not adequately account for the physiological perception of occupants, leading to uncomfortable and potentially dangerous virtual unbalance sensations due to vibration frequency beat effects caused by harmonic coupling between rotor blades.

Innovation Solution

A method that uses a neural network to adjust rotorcraft rotors by incorporating a 'knock' factor, which associates cabin vibration levels with occupant physiological perception, and involves a series of measurements and test flights to determine adjustment parameters for minimizing vibration and optimizing comfort and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing vibration adjustment methods are used to minimize measured vibration levels, then objective vibration measurements are improved, but physiological comfort of occupants deteriorates due to virtual unbalance sensations

Engineering Contradiction:
Improvevibration measurement accuracyVSAvoidoccupant physiological discomfort
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The invention transitions from a single-objective vibration minimization approach to a multi-dimensional optimization framework that simultaneously considers both measured vibration levels and physiological perception criteria. This is achieved by introducing a second objective function that models occupant comfort based on vibration characteristics, thereby adding a new dimension to the optimization problem that accounts for human sensory response beyond raw measurement data.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention implements a feedback mechanism where physiological perception models provide information back to the adjustment process. By incorporating models that predict how occupants perceive vibration based on measured characteristics, the system creates a closed-loop feedback system that continuously refines adjustment parameters to satisfy both measurement objectives and comfort requirements.

Inventive Principle:
Principle #23Feedback

2Productivity

If adjustment parameters are optimized solely based on measured vibration data, then vibration reduction efficiency is improved, but occupant comfort and safety deteriorate due to unaccounted physiological perceptions

Engineering Contradiction:
Improvevibration adjustment efficiencyVSAvoidoccupant comfort and safety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention changes the parameters of the optimization problem by introducing physiological perception models as additional objective functions. Instead of solely optimizing based on measured vibration magnitudes, the system now optimizes based on a composite set of parameters that includes both physical vibration measurements and modeled physiological responses, thereby transforming the optimization criteria to simultaneously achieve efficiency and reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite objective function that combines multiple types of information: measured vibration data and physiological perception models. This composite approach integrates different types of data and modeling results into a unified optimization framework, allowing the system to achieve both vibration reduction efficiency and occupant comfort by synthesizing multiple information sources into a single decision-making structure.

Inventive Principle:
Principle #40Composite materials

3Loss of time

If traditional neural network methods are used for rotor adjustment, then adjustment speed is improved, but accuracy in predicting physiological comfort deteriorates

Engineering Contradiction:
Improveadjustment timeVSAvoidcomfort prediction accuracy
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The invention applies preliminary action by pre-training neural network models with physiological perception data before actual rotor adjustment operations. By preparing these predictive models in advance with comprehensive training data that includes physiological response characteristics, the system enables rapid adjustments during operation while maintaining high accuracy in predicting occupant comfort, as the models are already calibrated to recognize comfort-relevant patterns.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention substitutes traditional trial-and-error mechanical adjustment methods with neural network-based predictive modeling. Instead of physically adjusting rotor parameters through iterative testing, the system uses trained neural networks to predict optimal adjustment parameters based on input vibration data and physiological models, thereby replacing time-consuming mechanical iteration with rapid computational prediction that maintains or improves accuracy.

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

Data Source

PatentUS7363120B2Method of adjusting at least one defective rotor of a rotorcraft
Publication Date: 2008.04.22 EUROCOPTER FRANCE SA
  • US7363120B2 patent drawing
  • US7363120B2 patent drawing
  • US7363120B2 patent drawing

AI summary

The present invention relates to a method of adjusting at least one defective, main or anti-torque rotor of a particular rotorcraft. The method uses a neural network representing the relationships between firstly accelerations representative of vibration generated on at least a portion of a reference rotorcraft, and secondly defects and adjustment parameters. After determining the defects, if any, of a defective rotor, an adjustment value α is defined for at least one of the adjustment parameters, advantageously by minimizing the following relationship:∑c⁢⁢λc⁢∑a⁢⁢λa⁢⁢ (∑h=1B-2⁢⁢(λh⁢Rc,a,h⁡(α)+γc,a,h2)+ λB-1(Rc,a,B-1⁡(α)+γc,a,B-12γc,a,B)2).