Magnetic Position Sensor with Redundant Field Detection
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Solution Overview
Problem
Position sensors used to detect the position of movable members, such as rods or pistons, face accuracy degradation due to environmental stress, thermal stress, shock, vibration, and aging of components, necessitating a system with enhanced precision.
Innovation Solution
A system comprising a movable member with secured magnets and a sensor assembly of magnetic sensors that detect magnetic fields, utilizing a data processor to determine axial positions based on sensed magnetic fields, providing redundancy and high resolution through multiple sensors and configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position sensor is used to detect the position of a movable member, then position detection is achieved, but precision is degraded by environmental stress, thermal stress, shock, vibration, and aging
Solution Approach 1:
The patent replaces mechanical contact-based position sensors with a magnetic field-based detection system. Magnets are attached to the movable member, and magnetic sensors on the fixed member detect their position through magnetic field interactions without physical contact. This eliminates mechanical wear, friction, and contact-related failures while maintaining position detection precision, directly resolving the contradiction between measurement precision and reliability under environmental stress.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary between the movable member and the fixed member for position detection. Instead of direct mechanical contact or electrical connections, the magnetic field serves as a non-contact mediator that transmits position information across the gap, eliminating the harmful effects of direct contact including wear, misalignment, and sensitivity to shock and vibration.
2Measurement precision
If multiple magnets and magnetic sensors are used to enhance precision, then position detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent divides the position detection system into discrete magnetic elements (multiple magnets attached at different positions on the movable member) and corresponding magnetic sensors arranged on the fixed member. Each magnet-sensor pair provides independent position information, and the combination of multiple such pairs enables precise determination of the movable member's position through coordinate geometry calculations, achieving high precision while maintaining manageable system complexity through modular segmentation.
Solution Approach 2:
The patent uses multiple magnets as simplified copies or representations of position information points. Instead of using a single complex sensor, multiple simple magnets and corresponding magnetic sensors create redundant position measurements that can be processed through mathematical relationships to achieve high-precision position detection, effectively copying position information through multiple simple channels rather than one complex sensor.
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
The system achieves enhanced precision and reliability in determining the position of movable members with reduced sensitivity to temperature and vibration, and without contacting parts prone to misalignment or wear, supporting accurate and robust position detection.
Implementation Method 1
A first magnet is secured to the movable member at a first axial position and is associated with a first magnetic field. A secondary magnet is secured to the movable member at a secondary axial position and is associated with a secondary magnetic field.
Data Source
AI summary
A first magnet is secured to the movable member at a first axial position and is associated with a first magnetic field. A secondary magnet is secured to the movable member at a secondary axial position and is associated with a secondary magnetic field. A sensor assembly comprises magnetic sensors arranged in an array (e.g., on a fixed member). A first magnetic sensor is spaced apart from the sensor assembly such that the first magnetic sensor detects the first magnetic field of the first magnet in a first state and an absence of or change in the first magnetic field in a second state. A data processor is arranged for determining an axial position of the moveable member based on at least one of the magnetic fields sensed by the sensor assembly.