Active Vibration Isolation Using Controllable Rotating Masses
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Solution Overview
Problem
Existing vibration isolation systems for rotating systems, such as helicopter rotor systems, are heavy, increase aerodynamic drag, and require frequent maintenance due to manufacturing imperfections and passive operation, failing to effectively isolate a wide spectrum of vibratory loads and adjust to varying operating conditions.
Innovation Solution
A vibration isolation system with controllable masses driven by independent electric motors and a control system that adjusts rotational speed and position to counteract vibratory loads, minimizing system weight and using lightweight, low-cost materials to reduce drag and maintenance costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive vibration isolators are used, then they can suppress vibrations at a predetermined frequency, but they cannot adjust to varying operating conditions and require frequent maintenance
Solution Approach 1:
The patent transforms the static, passive vibration isolator into a dynamic, active system by introducing controllable masses that can adjust their rotational speed and position in real-time. The isolator now actively responds to varying vibratory loads across different operating regimes, eliminating the need for frequent maintenance while maintaining adaptability.
Solution Approach 2:
The control system receives input signals indicative of the magnitude and phase of vibratory loads and automatically adjusts the rotational speed and position of the controllable masses to optimize vibration cancellation. This feedback mechanism ensures continuous adaptation to changing operating conditions without manual intervention or maintenance.
2Reliability
If traditional vibration isolators are used, then they can provide vibration isolation, but they increase system weight
Solution Approach 1:
The patent replaces heavy traditional mechanical vibration isolators with a lighter active control system using controllable masses driven by electric motors. This substitution maintains vibration isolation capability while significantly reducing system weight by eliminating the need for heavy passive isolation components.
Solution Approach 2:
The patent employs lightweight materials, specifically carbon fiber composite radial arms, to construct the vibration isolator components. This use of composite materials achieves the required structural strength and stiffness while minimizing the overall weight of the vibration isolation system.
3Reliability
If passive vibration isolators are used, then they can counteract vibrations, but they increase aerodynamic drag
Solution Approach 1:
The patent uses dynamically adjustable controllable masses that can optimize their configuration to minimize aerodynamic drag while maintaining vibration counteraction capability. The system adapts its mass distribution and positioning based on operating conditions, reducing drag compared to fixed passive isolators.
Solution Approach 2:
The patent changes the operational parameters of the vibration isolation system by using actively controlled masses with variable rotational speed and position, rather than fixed passive components. This allows optimization of both vibration cancellation performance and aerodynamic drag characteristics across different operating regimes.
4Manufacturing precision
If precision manufacturing is used for passive isolators, then they can achieve exact spring rates, but manufacturing costs increase
Solution Approach 1:
The patent replaces the need for precision-manufactured passive spring elements with an active control system using controllable masses and electric motors. This substitution eliminates the requirement for expensive precision manufacturing of springs while achieving equivalent or superior vibration isolation performance through active control.
Solution Approach 2:
The patent uses standard, easily manufactured components such as off-the-shelf electric motors and carbon fiber composite arms, replacing the need for expensive, precision-manufactured passive isolator components. This approach reduces manufacturing costs while maintaining effectiveness.
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 isolates large amplitude vibrations across a wide spectrum of operating speeds, reducing system weight and maintenance costs while maintaining optimal performance across varying operating regimes.
Implementation Method 1
driven by independent electric motors
Implementation Method 2
The isolation system employs two, essentially coplanar, masses that are (i) disposed at a predetermined distance from the axis of rotation of the rotating system, and (ii) driven in the same or opposing rotational direction as the rotating system at a rotational speed at least 3P greater than the rotational speed of the rotating system
Data Source
AI summary
A method and device for reducing vibratory noise in a system with an integral rotating member includes independently operable drive systems for controlling the angular velocity of at least two independently rotatable masses. Control signals manipulate the drive system to rotate each mass at optimal speed, direction and phase to reduce noise induced in the system by the rotating member.