Extended Range Position Sensor Using Segmented Magnet Arrays
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Solution Overview
Problem
Existing position sensors with magnetoresistive (MR) technology are limited to a detection range of up to 225 millimeters, which is insufficient for applications requiring larger ranges such as fork lifts or crane outriggers, necessitating an extension of position detection capabilities.
Innovation Solution
A position sensor system comprising multiple sets of magnets and sensors, with varying linear spacings, and a processor to generate position signals by comparing output signals from sensors associated with each set, allowing for detection ranges of up to 4 meters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single set of magnets with uniform spacing is used, then the sensor provides accurate position detection within its limited range, but the detection range is restricted to maximum 225 millimeters
Solution Approach 1:
The patent divides the detection range into multiple segments by using two separate sets of magnets (first set with spacing d1, second set with spacing d2) where each set covers a specific range. The processor selectively uses signals from one set or the other based on the current position, effectively segmenting the total detection range into manageable portions while maintaining accuracy in each segment.
Solution Approach 2:
The patent extends the detection range by adding a temporal dimension to the signal processing. The processor switches between different magnet sets based on position thresholds, creating a multi-dimensional approach where space (magnet spacing) and time (signal selection sequence) work together to achieve extended range while preserving measurement precision.
2Length of stationary object
If multiple sets of magnets with different spacings are used to extend range, then the detection range increases to up to 4 meters, but the device complexity increases
Solution Approach 1:
The patent makes the processor multi-functional by enabling it to handle signals from multiple magnet sets with different spacings. The same processor circuitry performs both short-range detection (using first magnet set) and long-range detection (using second magnet set) functions, reducing overall system complexity compared to having separate dedicated circuits for each range.
Solution Approach 2:
The patent changes the spatial parameter (magnet spacing) between different sets to achieve different detection ranges. The first set uses spacing d1 for short-range accuracy while the second set uses spacing d2 for extended range, allowing the system to adapt its detection characteristics by changing physical parameters rather than requiring completely different sensor systems.
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
Enables accurate and reliable position detection over extended ranges by leveraging the unique output signals generated from the relative movement between magnets and sensors, effectively addressing the limitations of current MR sensor technologies.
Implementation Method 1
One type of position sensor employs an array of magnetoresistive (MR) sensors to sense the position of a magnet
Data Source
AI summary
An extended range position sensor system includes a first set of spaced-apart magnets, a first sensor, a second set of spaced-apart magnets, a second sensor, and a processor. The first sensor is associated with and is movable relative to the first set of magnets, and is configured to generate a first sensor output signal in response to relative movement between the first sensor and the first set of magnets. The second sensor is associated with and is movable relative to the second set of magnets, and is configured to generate a second sensor output signal in response to relative movement between the second sensor and the second set of magnets. The processor is coupled to receive the first and second sensor output signals and is configured, in response thereto, to generate a position signal.