Linear Motion Position Measuring Mechanism With Dual-Side Sensors

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Solution Overview

Problem

Current position measurement systems for linear motion systems, such as DSPM-LSM, face challenges in achieving high precision and bidirectional movement while maintaining system modularization and reducing sensor quantity, accuracy, and long-term repeatability due to temperature deformation and offset changes.

Innovation Solution

A position measuring mechanism that uses two sensors disposed on either side of the stator, with a moving portion equipped with a magnet array and signal units, and a processing unit to combine signals from these sensors to calculate the movement path and adjust the movement pattern, allowing for bidirectional movement without increasing sensor quantity and ensuring accurate position feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If multiple sensors are arranged along the moving direction with overlapping measuring ranges, then the measuring range covers the entire moving range of the carrier, but the device complexity and sensor quantity increase

Engineering Contradiction:
Improvemeasuring rangeVSAvoidsensor arrangement complexity
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent transitions from a one-dimensional linear arrangement of sensors along the moving direction to a two-dimensional configuration where sensors are placed on both sides of the stator. This dimensional change allows the measuring range to be extended while reducing the number of sensors needed, as each sensor can utilize magnetic field information from both sides of the stator structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Each sensor in the patent serves multiple functions: it detects magnetic field strength, determines positional information, and contributes to calculating both forward and backward movement distances. This multi-functionality reduces the need for additional specialized sensors, thereby simplifying the overall system while maintaining comprehensive measurement coverage.

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

2Device complexity

If a single sensor is used for position feedback, then the system is simpler, but the carrier can only move in one effective direction and acting force is significantly reduced when moving in opposite direction

Engineering Contradiction:
Improvesensor quantityVSAvoidbidirectional movement capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent employs an asymmetric sensor configuration where sensors are positioned on both sides of the stator rather than symmetrically or in a single location. This asymmetric arrangement enables the system to detect magnetic field changes effectively in both forward and backward directions, providing bidirectional movement capability while maintaining system simplicity.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

By placing sensors on both sides of the stator (utilizing the spatial dimension), the system achieves bidirectional sensing capability with a limited number of sensors. This spatial configuration allows each sensor to contribute to both forward and backward movement detection, eliminating the need for separate sensors for each direction.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If sensors, servo drivers, and processing units are arranged in a special digital network, then position feedback is achieved, but long-term repeatability decreases due to temperature deformation and offset changes

Engineering Contradiction:
Improveposition feedback accuracyVSAvoidlong-term repeatability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the processing unit continuously receives magnetic field strength information from sensors, calculates positional deviations, and adjusts the carrier position accordingly. This closed-loop feedback system compensates for temperature deformation and offset changes, maintaining long-term repeatability while achieving high measurement precision.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-calibration and self-correction by using the magnetic field information from both sides of the stator to detect and compensate for positional offsets and temperature-induced deformations. This self-service capability reduces reliance on external calibration mechanisms and maintains reliability over time.

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 solution enhances the accuracy and sensitivity of position feedback, maintains system modularization, and improves long-term repeatability by processing signals from multiple sensors to determine exact positions and adjust movement patterns effectively.

Implementation Method 1

a first sensing portion and a second sensing portion respectively disposed on the base at intervals for sensing a magnetic field of the magnet array

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Data Source

PatentEP4030146B1Position measuring mechanism and measuring method of linear motion system
Publication Date: 2024.07.17 HIWIN MIKROSYST
  • EP4030146B1 patent drawingFigure 1
  • EP4030146B1 patent drawingFigure 2
  • EP4030146B1 patent drawingFigure 3

AI summary

The invention discloses a position measuring mechanism and a measuring method of a linear motion system in which two sensors are respectively disposed on two sides of a stator, in addition to allowing a moving portion to perform bidirectional movement, under a premise of not increasing a quantity of the sensors, a measuring range of the sensors can be calculated based on information measured by the sensors themselves. Furthermore, the invention further combines measurement sections respectively measured by the two sensors to ensure an accuracy of position feedback, instead of the conventional technique using an operational method of combining sinusoidal and cosine signals.