Actuator Position Sensing via Parallel Transmission Paths

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Solution Overview

Problem

Conventional actuator systems for position sensing are complex, bulky, and expensive due to the need for movement conversion and amplification or reduction gear mechanisms, leading to inaccuracies in position measurement.

Innovation Solution

The system integrates position sensing in two parallel transmission paths with different ratios, providing the difference between their outputs as an input to a position sensor, thereby simplifying the interface and reducing the need for reduction gearing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If movement conversion and amplification or reduction gear mechanisms are used in conventional actuator systems, then position sensing is achieved, but the system becomes complex, bulky, and expensive with manufacturing difficulties and cost

Engineering Contradiction:
Improveposition sensing accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical gear mechanisms with a magnetic coupling system. A magnetic coupling device directly couples the sensor shaft to the sensor without requiring intermediate gear wheels, reduction gearboxes, or other mechanical transmission components. This substitution of mechanical systems with a magnetic field-based coupling achieves position sensing while eliminating the complexity, bulk, and manufacturing difficulties associated with conventional gear mechanisms.

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

2Measurement precision

If movement conversion and amplification or reduction gear mechanisms are used in conventional actuator systems, then position sensing is achieved, but the system becomes bulky and expensive to manufacture

Engineering Contradiction:
Improveposition sensing accuracyVSAvoidmanufacturing ease
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The magnetic coupling device eliminates the need for precision-manufactured gear wheels, reduction gearboxes, and other complex mechanical components that are difficult and expensive to manufacture. The magnetic coupling system uses simpler magnetic elements that can be more easily manufactured and assembled, directly coupling the sensor shaft to the sensor while reducing manufacturing complexity and cost.

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

3Reliability

If conventional position sensor assemblies with gear mechanisms are used, then position monitoring is achieved, but inaccuracies in position sensing occur

Engineering Contradiction:
Improveposition monitoring reliabilityVSAvoidposition sensing accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent eliminates mechanical gear mechanisms that introduce friction, backlash, and wear, all of which cause position sensing inaccuracies. The magnetic coupling device provides a direct, frictionless coupling between the sensor shaft and sensor, ensuring that the position signal is transmitted accurately without the errors introduced by mechanical transmission components, thereby improving both reliability and precision.

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

Data Source

PatentEP3459844B1Actuator position sensor mechanism
Publication Date: 2022.07.13 RATIER FIGEAC SAS
  • EP3459844B1 patent drawingFigure 1
  • EP3459844B1 patent drawingFigure 2
  • EP3459844B1 patent drawingFigure 3~4

AI summary

The system of the present disclosure provides two or more sensors located on two parallel transmission or kinematic paths (200, 300) having different ratios (r1, r2) with respect to the actuator position. Each sensor provides a different position measurement output and the difference between the sensor outputs provides a reduced indication of the position of the actuator/moved component. Integrating sensors in the reduction path avoids the need for the reduction gear mechanism.