Vibration Rectification Error Correction Circuit for Sensor Accuracy

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Solution Overview

Problem

Vibration rectification errors (VRE) in sensors with nonlinear output characteristics complicate correction computations and increase load, affecting measurement accuracy in systems like acceleration sensors used for environmental and structural monitoring.

Innovation Solution

A vibration rectification error correction circuit that includes a first correction circuit obtaining digital values from sensor outputs and correcting them using a product-based correction function, along with a frequency delta sigma modulation circuit and filter circuits to synchronize and adjust correction values and filter characteristics, reducing computational complexity and improving accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a correction computation is performed to correct the vibration rectification error in nonlinear sensor outputs, then measurement accuracy is improved, but the computational complexity and computation load increase

Engineering Contradiction:

Improvemeasurement accuracyVSAvoidcomputational complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The correction computation is divided into two separate circuits: a vibration rectification error correction circuit that corrects VRE using a dedicated correction value, and a nonlinearity correction circuit that corrects general nonlinearity. This segmentation allows each circuit to use optimized correction methods, reducing overall computational complexity while maintaining measurement accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A dedicated vibration rectification error correction value is introduced as an intermediary parameter. This correction value is calculated based on the resonance frequency and quality factor of the sensor, and is used to correct VRE before the nonlinearity correction step. This intermediary correction simplifies the overall computation by handling VRE separately from general nonlinearity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If feedback control is performed using a restoring force actuator to reduce vibration rectification error, then measurement accuracy is improved, but device complexity and control requirements increase

Engineering Contradiction:

Improvemeasurement accuracyVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The vibration rectification error correction function is extracted from the main feedback control system and implemented as a separate digital correction circuit. This extraction eliminates the need for additional physical components like restoring force actuators while achieving the same error reduction goal through signal processing.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical feedback control system using restoring force actuators is replaced with a digital signal processing approach. The correction computation is performed in the digital domain using the extracted VRE correction value, substituting mechanical components with electronic/digital processing elements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11808572B2Vibration rectification error correction circuit, physical quantity sensor module, structure monitoring device, and correction value adjustment method of vibration rectification error correction circuit

Publication Date: 2023.11.07 SEIKO EPSON CORP

AI summary

A vibration rectification error correction circuit includes a first correction circuit that obtains a digital value based on a signal to be measured output from a sensor element configured to measure a physical quantity and corrects a vibration rectification error of the digital value by a correction function based on a product of values obtained by biasing the digital value.