Torsion Balance Imbalance Compensation via Electronic Feedback

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Solution Overview

Problem

Paramagnetic gas sensors, particularly those using torsion balances, face challenges in accurately measuring partial pressures due to mechanical imbalances, which require costly and time-consuming balancing processes to ensure precise measurements.

Innovation Solution

The implementation of a method and apparatus that utilize a microelectromechanical system (MEMS) accelerometer and inclinometer to measure and compensate for mechanical imbalances, allowing for the calculation and application of compensation coefficients to correct for imbalance effects, thereby eliminating the need for precise mechanical balancing during manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mechanical balancing is performed during manufacturing to ensure measurement accuracy, then measurement precision is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical balancing system with an electronic compensation system. Instead of physically balancing the test body through mechanical adjustments during manufacturing, the system uses sensors to detect imbalance and applies electronic compensation signals to counteract the imbalance effects, thereby maintaining measurement accuracy while simplifying manufacturing processes

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the approach from mechanical parameter adjustment (physical balancing) to electrical parameter adjustment (compensation signals). By measuring imbalance parameters and applying compensating electrical signals, the system achieves the same measurement accuracy without requiring precise mechanical balancing

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If mechanical balancing is performed during manufacturing to ensure measurement accuracy, then measurement precision is improved, but manufacturing time increases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmanufacturing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs imbalance measurement and compensation calibration as a preliminary action during manufacturing, but this is a simple automated process compared to traditional mechanical balancing. The compensation parameters are determined once during calibration and stored for use during operation, eliminating the need for time-consuming mechanical adjustments while ensuring measurement accuracy

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If mechanical balancing is performed during manufacturing to ensure measurement accuracy, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive and time-consuming mechanical balancing operations with a more economical electronic compensation system. The compensation requires only simple sensors and signal processing, eliminating the need for skilled manual balancing and reducing manufacturing costs while maintaining measurement accuracy

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs self-diagnosis and self-compensation for mechanical imbalance. The sensors automatically detect imbalance conditions and the control system automatically applies compensation signals, eliminating the need for external balancing operations and reducing manufacturing complexity and cost

Inventive Principle:
Principle #25Self-service

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 simplifies the manufacturing process, reduces costs, and maintains accuracy comparable to balanced systems by enabling compensation for mechanical imbalances, allowing for looser manufacturing tolerances and improved sensitivity in paramagnetic gas measurements.

Implementation Method 1

measuring, with the accelerometer, an orientation of the test body relative to a gravitational field

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 2

A non-uniform magnetic field is applied across a chamber containing a test body. The non-uniform magnetic field causes a disturbing torque to be applied to the test body in the presence of a paramagnetic gas

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 3

the paramagnetic property of a test gas to measure the partial pressure of the test gas

Methodology Applied
Scientific EffectParamagnetism: Magnetism

Implementation Method 4

The non-uniform magnetic field causes a disturbing torque to be applied to the test body

Methodology Applied
Scientific EffectTorque: Torque

Implementation Method 5

The test body is held by a suspension filament, acting as a torsion spring, so as to allow the test body to have a single degree of rotational freedom

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 6

the filament behaves as a weak torsion spring

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Implementation Method 7

a controlled electrical current is passed through a conductor wound around the test body substantially perpendicular to the magnetic field in such a way that the torque generated through interaction of the current and the fixed magnetic field acts to oppose the disturbing torque

Methodology Applied
Scientific EffectElectromagnetic interaction: Lorentz Force

Data Source

PatentEP2363708B1Apparatus and methods for imbalance compensation
Publication Date: 2016.12.21 SERVOMEX GRP LTD
  • EP2363708B1 patent drawingFigure 1~2
  • EP2363708B1 patent drawingFigure 3~4
  • EP2363708B1 patent drawingFigure 5

AI summary

Provided are apparatus and methods for compensation of mechanical imbalance in a measurement apparatus, that provides options for increased accuracy and/or less expensive manufacture of a torsion balance. Orientation measurements are taken and an imbalance torque about the torsion spring's axis of rotation is determined, and used to calculate a compensation. The measurement apparatus of one embodiment includes a test body and a set of magnets for generating a first disturbing force on the test body in response to a paramagnetic gas. A conductor element in the magnetic field receives an electrical current that generates a second opposing force to the test body, under feedback control that varies the current until the test body achieves a balanced null position. The control signal required to achieve the fixed null position is measured. Corrections are then made for an imbalance mass by measuring the orientation of the apparatus relative to an acceleration or gravitational field and determining the imbalance torque resulting from the imbalance mass. Use of the invention can improve accuracy or reduce the cost of manufacture of a torsion balance, by enabling compensation for imbalances.