Hybrid Isolation Struts for Payload Vibration Control

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Solution Overview

Problem

Passive vibration isolation systems face limitations such as minimal low-frequency auto-alignment capability, large clearance requirements, poor high-frequency isolation, and inability to reduce amplitude of isolation side disturbances, while active systems are complex, heavy, and power-dependent, reducing reliability.

Innovation Solution

A hybrid isolation system incorporating passive and active mechanisms, featuring a kinematic arrangement of struts with accelerometer feedback and relative displacement measurements to enhance isolation performance across all frequencies, using lightly damped disc flexures and electromagnetic actuators for active alignment and vibration control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If passive isolation mechanisms are used, then high-frequency isolation is improved, but low-frequency auto-alignment capability deteriorates

Engineering Contradiction:

Improvehigh-frequency vibration isolationVSAvoidlow-frequency auto-alignment capability

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent combines passive isolation mechanisms (disc flexures providing mechanical compliance and isolation) with active control mechanisms (voice coil actuators providing electromagnetic force for alignment and disturbance rejection) into a hybrid system that achieves both high-frequency isolation and low-frequency auto-alignment capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements feedback control using accelerometers mounted on the payload to sense vibrations and control electronics to drive voice coil actuators, creating a closed-loop active control system that enhances low-frequency performance while maintaining high-frequency isolation

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If passive isolators are used, then high-frequency isolation is improved, but sway space requirements increase

Engineering Contradiction:

Improvehigh-frequency vibration isolationVSAvoidsway space

Core Design Contradiction:

Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The patent replaces purely mechanical passive isolation elements with a hybrid system incorporating electromagnetic actuators and electronic control, substituting mechanical sway space requirements with active control capabilities that achieve isolation with reduced physical clearance

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If active damping isolation systems are used, then low-frequency vibration damping is improved, but system complexity increases

Engineering Contradiction:

Improvelow-frequency vibration dampingVSAvoidsystem complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses voice coil actuators as intermediary elements that can provide active damping forces through electromagnetic fields, controlled by electronics that process accelerometer signals, creating a manageable level of complexity through modular sensor-actuator-control units

Inventive Principle:

Principle #24Intermediary (Mediator)

4Object-affected harmful factors

If active isolators are used, then low-frequency vibration damping is improved, but weight increases

Engineering Contradiction:

Improvelow-frequency vibration dampingVSAvoidisolator weight

Core Design Contradiction:

Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The patent implements partial active control by using voice coil actuators and accelerometers only on selected struts rather than all isolation elements, providing sufficient low-frequency damping performance while minimizing the added weight of active components

Inventive Principle:

Principle #16Partial or excessive action

5Object-affected harmful factors

If active isolators are used, then low-frequency vibration damping is improved, but reliability deteriorates due to power dependency

Engineering Contradiction:

Improvelow-frequency vibration dampingVSAvoidpower failure inoperability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent designs the hybrid system with passive disc flexure elements that provide inherent mechanical isolation and support capabilities, serving as a backup cushioning mechanism that maintains basic isolation functionality even when active power systems fail

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 hybrid system achieves improved vibration damping and isolation at both high and low frequencies, reducing required sway space and damping, while maintaining reliability by integrating active control with passive components.

Implementation Method 1

a voice coil actuator defined by a coil movable relative to a stationary permanent magnet

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

Passive roll-off is produced by a series of (e.g. two or more) disc flexures in each strut

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 3

accelerometer feedback on each of the six hybrid isolation struts

Methodology Applied

Scientific EffectAccelerometer measurement: Accelerometer

Data Source

PatentUS10422405B2Active strut control for vibration isolation of large payloads

Publication Date: 2019.09.24 THE BOEING CO

AI summary

A system and a method that isolate a payload from the effects of vibrations by providing an active feedback path that enhances the isolation performance of a passive vibration isolation system at all relevant frequencies. The system comprises a kinematic arrangement of three bipod pairs of hybrid isolation struts to produce a fully kinematic suspension system. The active enhancement mechanism incorporates accelerometer feedback on each of the six hybrid isolation struts, blended with relative displacement measurements, to produce a transfer function that provides a specified alignment of a suspended component (with another component) at low frequency, but inertial stabilization at high frequency. Passive roll-off is produced by a series of disc flexures in each hybrid isolation strut.