Aircraft Propeller Speed Control for Vibration Attenuation

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Solution Overview

Problem

Aircraft propellers driven by electric propulsion systems experience significant vibrations when spinning at the same speed, leading to structural damage, increased power consumption, and decreased ride quality, particularly in multi-rotor aircraft.

Innovation Solution

An electrical system controls each propeller's speed to avoid synchronized spinning and specific vibration-prone speed ranges, maintaining required thrust for aircraft stability and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If multiple propellers spin at the same speed to maintain aircraft stability, then aircraft stability is improved, but structural vibrations increase significantly

Engineering Contradiction:

Improveaircraft stabilityVSAvoidstructural vibrations

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The system intentionally creates asymmetric propeller speed distribution among multiple propellers. Instead of maintaining identical speeds for symmetry and stability, the control system deliberately varies speeds across propellers to avoid synchronized vibrations, accepting some asymmetry in the speed distribution as a trade-off for reducing harmful vibrations.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The control system dynamically adjusts propeller speed parameters in real-time. It modifies individual propeller speeds within operational ranges to avoid resonant frequencies and synchronized spinning conditions, while still maintaining overall aircraft stability through coordinated control of all propellers.

Inventive Principle:

Principle #35Parameter changes

2Power

If propeller speed is increased to achieve required thrust, then aircraft thrust is improved, but vibrations and structural fatigue increase

Engineering Contradiction:

Improveaircraft thrustVSAvoidstructural fatigue

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The system employs dynamic speed adjustment rather than fixed high-speed operation. Propeller speeds are continuously varied within operational ranges to meet thrust requirements while avoiding constant high-speed operation that causes fatigue. The control system adapts speeds based on flight conditions, payload, and environmental factors.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control system introduces periodic variations in propeller speeds to prevent sustained operation at resonant or fatigue-inducing speeds. By cycling speeds through different ranges while maintaining average thrust output, the system reduces cumulative structural fatigue while still achieving required power levels.

Inventive Principle:

Principle #19Periodic action

3Use of energy by moving object

If propellers operate in synchronized speed ranges, then power consumption is reduced, but vibrations and noise increase significantly

Engineering Contradiction:

Improvepower consumptionVSAvoidcabin noise

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The system deliberately creates asymmetric speed distributions among propellers to break synchronization. This prevents the constructive interference of vibrations and noise that occurs when propellers spin at identical speeds, even though it may slightly increase overall power consumption compared to perfectly synchronized operation.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The system converts what would be harmful synchronized vibrations into beneficial unsynchronized operation. By intentionally desynchronizing propeller speeds, the system transforms the potential harm of vibration and noise into an acceptable level of operation, prioritizing passenger comfort and structural health over minimal energy savings from synchronization.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS12377999B2Systems and methods for vibration attenuation in flight control of an aircraft

Publication Date: 2025.08.05 ARCHER AVIATION INC

AI summary

The present disclosure relates generally to flight control of electric aircraft and other powered aerial vehicles. In one embodiment, an electrical system for an aircraft is disclosed, comprising: at least one processor configured to: receive pilot input indicating a commanded aircraft state, determine an aircraft thrust for achieving the commanded aircraft state, retrieve at least one propeller parameter associated with propeller speeds, wherein the propeller parameter is determined to reduce a structural vibratory response in the aircraft. The at least one processor is further configured to determine a respective command for each propeller of the aircraft to achieve the determined aircraft thrust based on the at least one propeller parameter and control each propeller of the aircraft based on the corresponding respective command.