Accelerometer Calibration Using Gravity and Inclined Axis Locking

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Solution Overview

Problem

Existing acceleration sensors are not adequately calibrated for acceleration values exceeding ±1g, necessitating complex removal and reinstallation for recalibration, and rapid calibration methods lack legal traceability and accuracy.

Innovation Solution

An automated method and device for calibrating acceleration sensors, aligning the sensor axis to vertical and horizontal positions relative to Earth's surface, then locking it in an inclined operating position to transform detected acceleration values beyond ±1g into the range of 0g to 1g, using a displacement device like a servo motor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the accelerometer is removed for calibration, then calibration quality is improved, but device complexity and time consumption increase

Engineering Contradiction:
Improvecalibration qualityVSAvoidcomplexity of removal and reinstallation
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The calibration device enables the accelerometer to be calibrated in-situ without removal. The system uses self-contained calibration mechanisms including vibration excitation and gravitational field utilization, allowing the sensor to calibrate itself while remaining installed in the test object, thereby eliminating complex removal and reinstallation procedures

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

A calibration device acts as an intermediary between the accelerometer and the external calibration environment. This device provides controlled calibration stimuli (vibrations, gravitational positioning) directly to the installed sensor, serving as a bridge that enables accurate calibration without requiring sensor removal or complex external setups

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If quick calibration using gravitational field is used, then ease of operation is improved, but measurement precision deteriorates

Engineering Contradiction:
Improveease of quick calibrationVSAvoidaccuracy of acceleration measurement
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system performs preliminary calibration using the gravitational field by positioning the test object in specific orientations (horizontal and vertical positions). This preliminary gravitational calibration establishes baseline reference values that are then used to correct and enhance subsequent vibration-based measurements, improving overall measurement precision while maintaining operational simplicity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The calibration process utilizes changes in gravitational field orientation parameters by rotating the test object between horizontal and vertical positions. This parameter change approach allows the system to extract multiple calibration data points from simple gravitational effects, transforming an easy but imprecise method into a precise calibration procedure through systematic parameter variation

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the measuring range is extrapolated beyond ±1g, then adaptability is improved, but reliability deteriorates

Engineering Contradiction:
Improvemeasuring rangeVSAvoidreliability of measurement
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The calibration device dynamically adjusts calibration parameters based on the expected measurement range. By analyzing the operational requirements and adapting the calibration procedure accordingly (using appropriate vibration amplitudes, frequencies, and gravitational positioning), the system ensures accurate calibration across extended measurement ranges while maintaining reliability through dynamic optimization of calibration conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs periodic vibration excitation during calibration to characterize the accelerometer's response across different acceleration levels. This periodic action allows for the detection and correction of nonlinearities in the sensor response, enabling reliable measurements beyond the standard ±1g range by establishing accurate calibration curves through repeated cyclic testing

Inventive Principle:
Principle #19Periodic 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

Enables reliable, legally compliant, and high-quality acceleration measurements by automatically recalibrating sensors without manual intervention, ensuring accurate detection of values exceeding the calibrated range.

Implementation Method 1

the acceleration due to gravity acting on the accelerometer during this repositioning is then used to calibrate it

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP4513200B1Method for operating an acceleration sensor and sensor device
Publication Date: 2025.12.31 DEKRA SE
  • EP4513200B1 patent drawingFigure 1A~1C
  • EP4513200B1 patent drawingFigure 2A~2F
  • EP4513200B1 patent drawingFigure 3~4

AI summary

The invention relates to a method for operating an accelerometer (10) with a sensor axis (S) and a measuring axis (M), wherein a calibration process is carried out before the start of operation, in which the sensor axis (S) of the accelerometer (10) is aligned in a vertical position and a maximum value of an acceleration force along the sensor axis (S) is detected, wherein the maximum value is equated to the acceleration due to gravity of essentially 1g, and subsequently the sensor axis (S) of the accelerometer (10) is aligned in a horizontal position and a minimum value of the acceleration force along the sensor axis is detected, wherein the minimum value is equated to essentially 0g.The accelerometer (10) is then locked in an operating position with an angular orientation (α) between the sensor axis (S) and the measuring axis (M) between 0° and 90°, so that a sensor coordinate system of the accelerometer (10) transforms the measured acceleration values ​​occurring with respect to the measuring axis (M) into the sensor axis (S) in such a way that the calibrated accelerometer (10) can transform measured acceleration values ​​>1g into sensor acceleration values ​​between 0g and 1g with respect to the sensor axis (S).