Vibration Control for Non-Gaussian Velocity and Displacement
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Solution Overview
Problem
Current vibration control systems for vibration testers face challenges in generating non-Gaussian properties for kinematic quantities like velocity and displacement while maintaining the prescribed acceleration power spectral density (PSD), leading to limitations in test duration due to safety system activations and displacement limitations.
Innovation Solution
A vibration control system that uses sensors to detect vibration physical quantities, calculates corresponding PSDs, and applies inverse Fourier transforms to generate non-Gaussian waveforms, modifying equalization characteristics to ensure the test object is vibrated with desired non-Gaussian characteristics without exceeding safety limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Gaussian distribution is strictly followed for acceleration signal, then acceleration PSD requirement is satisfied, but velocity and displacement cannot have non-Gaussian properties required for realistic testing
Solution Approach 1:
The patent segments the vibration signal into multiple frequency components and processes each component independently. By dividing the acceleration signal into frequency bands and applying different processing to each band, the system can maintain Gaussian properties in acceleration while introducing non-Gaussian characteristics in velocity and displacement through selective manipulation of spectral components.
Solution Approach 2:
The patent transforms the problem from time-domain Gaussian constraints to frequency-domain spectral manipulation. By working in the frequency domain and using spectral folding techniques, the system achieves non-Gaussian properties in integrated quantities (velocity, displacement) while maintaining Gaussian acceleration, effectively solving the contradiction through dimensionality change from time to frequency domain.
2Reliability
If maximum acceleration is maintained within limits, then safety requirements are met, but test duration is reduced due to safety system activations
Solution Approach 1:
The patent applies preliminary spectral folding processing to the acceleration signal before it reaches the vibration generator. By pre-shaping the spectral content to limit peak accelerations while maintaining overall PSD requirements, the system prevents safety system activations and extends test duration without compromising safety or test validity.
3Reliability
If displacement limits are strictly enforced, then safety requirements are met, but realistic non-Gaussian velocity and displacement waveforms cannot be generated
Solution Approach 1:
The patent resolves this contradiction by moving the control strategy to the frequency domain through spectral folding. Instead of directly limiting displacement in the time domain, the system manipulates spectral components to achieve implicit displacement control while allowing rich non-Gaussian waveform characteristics, thus maintaining both safety and waveform flexibility.
4Reliability
If conventional vibration control methods are used, then acceleration PSD is controlled, but corresponding PSDs for velocity and displacement cannot be independently controlled
Solution Approach 1:
The patent implements a universal spectral folding control mechanism that simultaneously controls acceleration PSD and derives corresponding PSDs for velocity and displacement through the same spectral manipulation framework. This multi-functional approach allows independent control of multiple PSDs without requiring separate control systems, reducing overall complexity while expanding control capability.
Data Source
AI summary
A vibration control device, while applying Gaussian vibration that matches a target vibration physical quantity PSD to a test piece, makes a corresponding vibration physical quantity non-Gaussian. Using a response vibration physical quantity PSD and a target vibration physical quantity PSD, a control vibration physical quantity PSD calculation generates a control vibration physical quantity PSD for generating a drive signal. A PSD conversion converts the control vibration physical quantity PSD into a control corresponding vibration physical quantity PSD of another dimension. Using the control corresponding vibration physical quantity PSD, a control corresponding vibration physical quantity waveform calculation calculates a control corresponding vibration physical quantity waveform that is non-Gaussian. At least based on the control characteristics and the control corresponding vibration physical quantity waveform, a drive waveform calculation generates a next drive waveform such that vibration that matches the control corresponding vibration physical quantity waveform is applied to a test piece.