Transducer Acceleration Compensation via Phase Delay

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Solution Overview

Problem

Existing transducer systems face inaccuracies due to inertial errors caused by additional mass during acceleration, which traditional compensation methods only partially address, especially at lower frequencies where minor phase differences limit the effectiveness of acceleration compensation.

Innovation Solution

A method and system that provide phase compensation by applying a delay to the acceleration signal based on the phase versus frequency characteristics, optimizing compensation over a desired frequency range by approximating the phase characteristic at frequencies below the first modal frequency, thereby improving accuracy in transducer measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional acceleration compensation is used with a scalar value multiplied by measured acceleration, then transducer accuracy is significantly improved, but measurement precision deteriorates at lower frequencies due to uncorrected phase differences

Engineering Contradiction:
Improvetransducer accuracyVSAvoidmeasurement precision at lower frequencies
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies phase compensation by introducing a frequency-dependent phase shift to the acceleration compensation signal. The phase angle φ is calculated as φ = -arctan(ω/ωn) + arctan(ω/ωd), where ω is the excitation frequency, ωn is the natural frequency, and ωd is the damped natural frequency. This parameter change in the phase domain corrects the phase mismatch between the transducer output and acceleration signal, thereby improving measurement precision at lower frequencies while maintaining overall reliability.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If phase compensation is applied across all frequencies, then measurement precision is improved, but device complexity increases due to the need for frequency-dependent compensation

Engineering Contradiction:
Improvemeasurement precisionVSAvoidcompensation system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements phase compensation specifically targeted at the frequency range below the first modal frequency, where phase differences most significantly impact measurement precision. The compensation formula φ = -arctan(ω/ωn) + arctan(ω/ωd) is applied selectively rather than uniformly across all frequencies. This partial action approach improves measurement precision in the critical low-frequency range while avoiding the excessive complexity that would result from implementing full-spectrum phase compensation.

Inventive Principle:
Principle #16Partial or excessive action

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 approach effectively enhances the accuracy of transducer measurements by eliminating linear phase versus frequency differences, improving the effectiveness of acceleration compensation at lower frequencies, even when modal frequencies are beyond the range of interest, through a simple yet powerful delay compensation technique.

Implementation Method 1

The compensator compensates the signal providing phase compensation by application of a delay

Methodology Applied
Scientific EffectPhase compensation through time delay:

Data Source

PatentEP2850406B1Transducer acceleration compensation using a delay to match phase characteristics
Publication Date: 2018.10.24 MTS SYSTEMS CORPORATION
  • EP2850406B1 patent drawingFigure 1
  • EP2850406B1 patent drawingFigure 2
  • EP2850406B1 patent drawingFigure 3

AI summary

A method and system for correcting for the inertial error of a transducer (10) as a function of frequency by applying a delay (21, 48) to a leading signal of the transducer (10) to provide phase compensation.