Variable Rotary Mass Control for Rotor Hub Vibration Suppression
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Solution Overview
Problem
Conventional vibration suppression systems in rotary-wing aircraft, such as helicopters, face challenges in effectively mitigating vibrations at the source, leading to structural fatigue and transmission of vibrations to other systems, as existing technologies often rely on active counter-vibration devices or hub-mounted systems that may not adequately address the root cause of vibrations near the rotor system.
Innovation Solution
A variable rotary mass vibration suppression system is introduced, comprising two vibration control masses with selectively variable displacement angles and rotational speeds, controlled by a motor and Cg motor system, which generates a controllable vibration control force vector to counteract vibrations by synchronizing the rotational directions and speeds of the masses and their respective axes, thereby reducing in-plane vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional active counter-vibration devices are used, then vibrations can be suppressed at remote locations, but the vibration suppression effectiveness at the source is insufficient
Solution Approach 1:
The patent extracts the vibration suppression function from remote locations and places it directly at the vibration source (rotor hub). The counterbalancing masses are mounted on the rotor hub to generate counter-vibrations proximate to the source, thereby improving suppression effectiveness while maintaining manageable system complexity through modular integration.
Solution Approach 2:
The patent introduces independently controllable counterbalancing masses as intermediaries between the rotor system and the aircraft structure. These masses rotate independently of the rotor blades and generate counter-vibrations that directly counteract the source vibrations, serving as a mediator that improves suppression effectiveness without requiring complex remote active control systems.
2Reliability
If hub mounted vibration isolation systems are used, then vibrations are suppressed proximate to the source, but the system cannot adequately address in-plane vibrations
Solution Approach 1:
The patent employs independently controllable counterbalancing masses that can dynamically adjust their rotational speeds and orientations. The first counterbalancing mass rotates about a first axis and the second counterbalancing mass rotates about a second axis, with independent control enabling the system to adapt to and suppress vibrations in multiple directions including in-plane vibrations, thereby enhancing both effectiveness and versatility.
Solution Approach 2:
The patent extends vibration suppression from a single plane to three-dimensional space by introducing counterbalancing masses that rotate about different axes. The first counterbalancing mass rotates about a first axis and the second counterbalancing mass rotates about a second axis, enabling the system to address vibrations in multiple directions and planes, thereby improving adaptability to various vibration modes.
3Reliability
If multiple independently rotatable masses are used, then in-plane vibrations are reduced, but the motor power requirements increase
Solution Approach 1:
The patent uses two counterbalancing masses instead of requiring three or more masses that would be needed for complete three-axis vibration cancellation. This partial action approach targets the dominant in-plane vibration modes effectively while avoiding the excessive motor power requirements that would result from controlling additional masses, thereby optimizing the balance between suppression effectiveness and energy consumption.
4Strength
If conventional vibration control systems are used, then structural fatigue is partially mitigated, but vibration transmission to other systems persists
Solution Approach 1:
The patent applies preliminary anti-action by generating counter-vibrations at the source before vibrations can propagate to other systems. The counterbalancing masses rotate in opposition to the rotor blades, creating counter-forces that cancel the source vibrations in real-time, thereby preventing both structural fatigue and vibration transmission to other aircraft systems simultaneously.
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
This system effectively suppresses vibrations by generating a controlled vibration control force vector, reducing structural fatigue and minimizing vibration transmission, while maintaining operational efficiency and minimizing motor power requirements.
Implementation Method 1
a first vibration control mass 116 having a first center of mass 118; a first Cg input driver 119 rotationally coupled to the first mass 116 such that the first center of mass 118 rotates about a first Cg axis 120... the first center of mass 118 offset a first Cg radial distance 121 from the first Cg axis 120
Data Source
AI summary
A vibration suppression unit for an aircraft comprising a vibration control frame adapted to be mounted to the aircraft and to rotate about a central axis, a first motor configured to rotate the vibration control frame about the central axis, a second motor configured to rotate a first and second center of mass about a first and second axis or rotation, a third motor configured to adjust a variable distance between the first and second centers of mass and the first and second axis of rotation, respectively, and a controller for receiving input signals and outputting command signals to the first, second and third motors.