Variable Rotary Mass Assembly for Helicopter Vibration Suppression
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Solution Overview
Problem
Current vibration suppression systems for rotary-wing aircraft, such as helicopters, are inadequate in effectively managing vibrations transmitted from the rotor to the fuselage, leading to structural fatigue and inefficient vibration control, particularly when active counter-vibration devices are not strategically positioned close to the source of vibrations.
Innovation Solution
A variable rotary mass vibration suppression system is introduced, comprising a vibration control mass assembly with a center of mass that can be selectively displaced radially and rotationally controlled by amplitude and frequency rotors, producing a controllable vibration control force vector. This system includes motors and a controller to adjust the displacement angle and rotational speeds of the rotors to optimize vibration reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active counter-vibration devices are used to suppress vibrations, then vibration control effectiveness is improved, but device complexity increases
Solution Approach 1:
The vibration control system is segmented into multiple independent rotatable masses (at least two masses) that can be independently controlled. Each mass can be rotated about the axis of rotation to generate counter-vibration forces, allowing the system to address different vibration frequencies and directions separately, thereby improving vibration control effectiveness while maintaining manageable complexity through modular independent control
Solution Approach 2:
The system employs dynamic control by independently rotating multiple masses about the rotor axis. The control system adjusts the rotational speed and phase of each mass dynamically to optimize vibration cancellation at different operating conditions, making the vibration suppression adaptive and effective across varying flight regimes
2Reliability
If multiple independently rotatable masses are used to reduce vibrations, then vibration suppression capability is improved, but device complexity increases
Solution Approach 1:
Multiple rotatable masses are merged into a single hub assembly that rotates about the rotor axis. The masses are positioned at different radial distances and angular positions, allowing them to work together as an integrated system rather than separate devices, thereby improving vibration suppression capability while consolidating the structure to manage complexity
3Reliability
If vibration control system is positioned proximate to the rotor source, then vibration suppression effectiveness is improved, but device complexity increases
Solution Approach 1:
The vibration control masses are positioned in the radial dimension at different distances from the rotor axis, creating a multi-dimensional mass distribution. This radial arrangement allows the system to generate counter-vibration forces more effectively close to the vibration source while utilizing the radial space efficiently, improving suppression effectiveness without excessive structural complexity
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 effectively suppresses vibrations by dynamically adjusting the center of mass's radial displacement and rotational position, reducing structural fatigue and improving vibration control efficiency by generating a controllable force vector that counteracts rotor-induced vibrations.
Implementation Method 1
the frequency rotor driven to rotate the frequency center axis (38) about the central axis of rotation (20)... the amplitude rotor driven independently of the frequency rotor to rotate the amplitude center axis (32) about the central axis of rotation (20)... wherein the amplitude rotor and the frequency rotor are controllable to produce a vibration control force vector (42) having a controllable magnitude and frequency about the central axis of rotation
Data Source
AI summary
A vibration suppression unit for an aircraft comprising a mass assembly having a center of mass and a frequency rotor having a frequency center axis offset from a central axis of rotation and driven to rotate about the central axis, a vibration control amplitude rotor rotationally coupled to the mass assembly and having an amplitude center axis offset from the central axis driven independently of the frequency rotor to rotate about the central axis, the amplitude center axis and the frequency center axis having a selectively variable displacement angle defined by an inclusive angle between a line extending between the central axis and the amplitude center axis and a line extending between the central axis and the frequency center axis, wherein the amplitude rotor and the frequency rotor are controllable to produce a vibration control force vector having a controllable magnitude and frequency about the central axis of rotation.