Independent Cart Position Sensing With Redundant Sensor Verification

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Solution Overview

Problem

Existing motion control systems with independent carts lack sufficient diagnostic coverage for position sensors, which is crucial for ensuring safety integrity, especially when human interaction or maintenance is required along the track.

Innovation Solution

Implementing multiple sets of position sensors and processing cores to generate and compare position feedback signals, verifying sensor operation and detecting edges of the mover to determine accurate positioning, thereby enhancing diagnostic coverage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple sets of position sensors are implemented to improve diagnostic coverage, then safety integrity is enhanced, but device complexity increases

Engineering Contradiction:
Improvesafety integrityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The position sensing system is divided into multiple independent sensor sets (first position sensors and second position sensors), each capable of independently detecting mover position. This segmentation allows the system to achieve higher safety integrity through redundancy while managing complexity by organizing sensors into distinct functional groups that can be monitored separately.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the parameter of sensor quantity from a single set to multiple sets, transforming the diagnostic coverage capability. By implementing multiple sensor sets with different failure modes, the system achieves enhanced safety integrity levels without requiring complete system redesign,而是通过参数变化实现改进。

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple processing cores are used to compare position feedback signals, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveposition detection accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Multiple processing cores independently process position feedback signals from different sensor sets and compare their results. This feedback mechanism allows the system to verify position measurements through cross-validation, improving measurement precision while distributing the computational complexity across multiple dedicated processing units rather than requiring a single complex processor.

Inventive Principle:
Principle #23Feedback

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

Improves the accuracy and reliability of position detection in independent cart systems, ensuring safety by reducing the likelihood of errors and enhancing safety integrity levels.

Implementation Method 1

Each of the first and second position sensors are configured to detect the magnet array to generate the first and second position feedback signals

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP4345422B1System and methods for achieving position detection integrity in an independent cart system
Publication Date: 2026.03.11 ROCKWELL AUTOMATION TECH INC
  • EP4345422B1 patent drawingFigure 1
  • EP4345422B1 patent drawingFigure 2~4
  • EP4345422B1 patent drawingFigure 5~6

AI summary

A system and method for detecting integrity of a position for a mover in an independent cart system, includes receiving multiple first position feedback signals at a first processing core and receiving multiple second position feedback signals at a second processing core. Each of the first and second position feedback signals are generated by first and second position sensors, respectively, by detecting a magnet array mounted on the mover. A first value of the position of the mover is generated with the first processing core responsive to the first position feedback signals, and a second value of the position of the mover is generated with the second processing core responsive to the second position feedback signals. The first and second values of the position of the mover are compared with either the first or second processing core to verify operation of the first and second position sensors.