Weighing Apparatus Vibration Compensation Using Accelerometer

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Solution Overview

Problem

Existing weighing systems face challenges in accurately measuring mass due to noise from vibrations, particularly low-frequency noise, which can be difficult to remove through filtering processes, and may require specialized apparatus for calibration.

Innovation Solution

A weighing apparatus and system that utilize a load detection device and an acting force detection device, such as an accelerometer, to calculate correction coefficients based on the outputs of both devices when the system is in different attitudes, allowing for the subtraction of noise without the need for a specialized apparatus that applies standard reference vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If filtering process is applied to remove noise from load cell data, then measurement precision is improved, but measurement responsiveness deteriorates due to excessive filtering

Engineering Contradiction:
Improvenoise removalVSAvoidmeasurement responsiveness
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The patent segments the vibration removal task into two parts: high-frequency vibrations are removed by traditional filtering, while low-frequency vibrations are removed by a separate correction process using acceleration sensor data. This segmentation allows each method to target specific frequency ranges, improving overall effectiveness without excessive filtering that would harm responsiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an acceleration sensor as an intermediary device to detect vibrations independently. The acceleration sensor output serves as a mediator that provides vibration information without directly interfering with the load cell measurement signal, enabling correction of low-frequency vibrations without degrading measurement responsiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If traditional vibration compensation using the same weighing sensor is used, then vibration noise is removed, but installation space and cost increase

Engineering Contradiction:
Improvevibration compensationVSAvoidinstallation space and cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the acceleration sensor serve multiple functions: it detects vibrations for correction purposes and also provides information about the scale's orientation and movement. This multi-functionality reduces the need for additional specialized sensors, thereby reducing installation space and cost while maintaining vibration compensation capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of using the same weighing sensor for vibration detection, the patent uses a separate acceleration sensor that copies the vibration information in a different physical domain (acceleration vs. force). This copying approach allows vibration compensation without requiring additional components in the weighing sensor path, reducing complexity and cost.

Inventive Principle:
Principle #26Copying

3Measurement precision

If correction coefficient is calculated using specialized apparatus with standard reference vibration, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecorrection coefficient accuracyVSAvoidspecialized apparatus
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent enables the scale to calculate its own correction coefficient using only its existing components (load cell and acceleration sensor) and environmental vibrations. The system performs self-calibration by detecting vibrations during normal operation and automatically computing the correction coefficient, eliminating the need for specialized external calibration apparatus and reducing overall system complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the approach to correction coefficient calculation from using fixed standard reference vibrations to using actual environmental vibrations detected during operation. By adapting to varying vibration conditions and calculating the coefficient dynamically based on real-world data, the system achieves accurate correction without requiring specialized calibration equipment.

Inventive Principle:
Principle #35Parameter changes

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 enables accurate mass measurement by compensating for vibration noise, improving measurement responsiveness, and reducing installation space and cost by eliminating the need for additional sensors.

Implementation Method 1

a load detection device provided to detect a load acting on the load receiving device

Methodology Applied
Scientific EffectLoad detection: Force

Implementation Method 2

an acting force detection device provided to detect a force that is acting on the main body

Methodology Applied
Scientific EffectAcceleration detection: Accelerometer

Data Source

PatentEP2851660B1Weighing apparatus, weighing system, weighing method, and program
Publication Date: 2017.04.05 TANITA CORP
  • EP2851660B1 patent drawingFigure 1~2
  • EP2851660B1 patent drawingFigure 3~4
  • EP2851660B1 patent drawingFigure 5

AI summary

A weighing apparatus for weighing a mass of an object is provided with: a body; a load receiving device, a load detection device, an acting force detection device, and a data processing device configured to data-process an output of the load detection device as a weighed value in a mass unit. The data processing device has: a load output acquisition unit configured to acquire an output of the load detection device; a force output acquisition unit configured to acquire an output of the acting force detection device; and a correction coefficient calculation unit configured to calculate, as a correction coefficient for correcting an output of the load detection device, a change amount of an output of the load output acquisition unit with respect to a change amount of an output of the acting force detection device based on (i) outputs of the load detection device and the acting force detection device acquired respectively by the load output acquisition unit and the force output acquisition unit, when the weighing apparatus with zero load applied thereto is placed in a first attitude and (ii) outputs of the load detection device and the acting force detection device acquired respectively by the load output acquisition unit and the force output acquisition unit, when the weighing apparatus with zero load applied thereto is placed in a second attitude, which differs from the first attitude.