Rotor Hub Radial Actuators for Vibration Attenuation
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Solution Overview
Problem
Existing rotor hub vibration control systems for rotorcraft are limited in frequency range, weight penalty, and fail to effectively cancel discrete directional vibrations, often coupling vibrations and not located in the primary vibration path.
Innovation Solution
A rotor hub with a yoke structure and elastomeric members that transfers torque while being compliant to attenuate vibrations, combined with radially oriented actuators that selectively counteract vibrations by displacing the yoke relative to the mast, using a control system to analyze and command the actuators for precise vibration attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive vibration control systems (pendulum dampers, bifilar dampers, spring mass dampers, pylon isolators) are used, then vibration attenuation is achieved, but weight penalty increases and frequency range is limited
Solution Approach 1:
The patent replaces traditional passive mechanical vibration control systems (pendulum dampers, spring mass dampers) with an active control system using actuators and a control algorithm. The active system processes vibration signals and applies targeted counter-vibrations through actuators positioned in the primary vibration path, achieving superior attenuation without the weight penalty of bulky passive systems.
Solution Approach 2:
The patent introduces an intermediary control algorithm that processes vibration signals from sensors and generates appropriate actuator commands. This intermediary layer enables intelligent vibration cancellation by analyzing vibration characteristics and coordinating actuator responses, achieving effective control with reduced system weight compared to purely mechanical approaches.
2Object-affected harmful factors
If active vibration control systems are used, then vibration cancellation is attempted, but vibrations become coupled and cannot be canceled individually, and systems are not located in the primary vibration path
Solution Approach 1:
The patent segments the vibration control into individual directional components by positioning actuators to address specific vibration modes (flapping, lead-lag, hub shift) independently. Each actuator is oriented to counteract vibrations in its specific direction, allowing individual vibration cancellation rather than treating all vibrations as a single coupled frequency problem.
Solution Approach 2:
The patent applies local quality by positioning actuators specifically in the primary vibration path at the rotor hub, where vibrations are most intense. The actuators are oriented in specific directions (radially inward, tangentially, axially) to target and cancel vibrations in those particular directions, providing localized and effective vibration cancellation for each mode.
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
Substantially eliminates oscillatory vibrations in the rotor hub, preventing their transmission to the rotorcraft body, effectively addressing the limitations of existing systems by providing comprehensive and precise vibration control across various modes.
Implementation Method 1
A rotor hub with a yoke structure and elastomeric members that transfers torque while being compliant to attenuate vibrations
Implementation Method 2
radially oriented actuators that selectively counteract vibrations by displacing the yoke relative to the mast
Data Source
AI summary
A rotor hub can include a yoke, a mast, and one or more radially oriented actuators. The first radial actuator and the second radial actuator each have a piston configured to impart a translation of the yoke relative to the mast. The radial actuators are configured to attenuate in-plane whirling vibrations. The rotor hub can also have actuators coupled between the mast and the yoke for attenuating flapping and vertical vibrations.