3D Hall Sensor Position Measurement with Signal Storage
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Solution Overview
Problem
Existing contactless magnetic displacement sensors face challenges in maintaining signal precision and range due to weak magnetic control fields at the ends of their measurement range, leading to unfavorable signal-to-noise ratios and the need for larger magnets to cover entire displacement ranges.
Innovation Solution
Incorporating a storage unit in the magnetic field sensor to store the last valid position value when the magnetic field is lost, allowing for continuous output of valid sensor signals until the magnet re-enters the detection range, thereby extending the usable displacement range without requiring stronger magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the measurement range is extended to cover larger displacement paths, then the sensor can detect movements over a greater distance, but the magnetic control field becomes very weak at the ends of the measurement range causing unfavorable signal-to-noise ratios
Solution Approach 1:
The patent applies preliminary action by storing the last valid measurement value in a storage unit (register) before the magnetic field becomes too weak to provide reliable measurements. This stored value is continuously output even when the magnet moves beyond the detection range, preventing signal degradation while maintaining measurement range extension.
Solution Approach 2:
The storage unit acts as an intermediary between the Hall sensor and the output signal. When the magnetic field strength drops below a threshold, the storage unit mediates by providing the last valid measurement value instead of allowing the weak field to directly affect the output, thus maintaining signal quality while extending range.
2Measurement precision
If a larger magnet is used to maintain magnetic field strength over larger displacement ranges, then the signal-to-noise ratio is improved, but the device size and complexity increase
Solution Approach 1:
The patent extracts the measurement value from the magnetic field source and stores it separately in a storage unit. This separation allows the magnet to remain small while the measurement information is preserved and output independently, eliminating the need for large magnets to maintain field strength over extended ranges.
Solution Approach 2:
The storage unit creates a copy of the last valid measurement value and continues outputting this copied value when the magnet moves beyond detection range. This copying mechanism allows small magnets to effectively serve large displacement ranges without requiring the magnet itself to be enlarged.
3Measurement precision
If the magnetic field strength is increased to maintain control over larger displacement paths, then measurement precision is improved, but the device complexity and power requirements increase
Solution Approach 1:
The system performs preliminary action by capturing and storing the measurement value while the magnetic field is still strong, then using this pre-captured value when the field weakens. This eliminates the need for continuous high power output to maintain field strength over extended ranges.
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 enables precise measurement in a defined partial range with improved signal-to-noise ratios and allows for the use of smaller magnets, ensuring stable operation over larger displacement paths without hardware or software disruptions.
Implementation Method 1
a magnetic field sensor which can be displaced relative to each other along a predetermined path. The magnetic field sensor measures two components of the magnetic field produced by the magnetic field source.
Data Source
AI summary
The present invention relates to a method for contactlessly measuring a relative position of a magnetic field source (102) which produces a magnetic field and a magnetic field sensor (100) in relation to each other. The present invention further also relates to a corresponding displacement sensor. The invention describes an operating principle of a sensor which is based on the Hall effect and which achieves an increase in the sensor output range with a magnet which is simultaneously reduced in size by storing the earlier value when control by the magnetic field is lost. In particular, the method comprises the steps of: calculating the position signal on the basis of a quotient of two magnetic flux density components; calculating a magnitude of the magnetic flux density and comparing the magnitude with a predetermined threshold value; outputting the current calculated position signal if the magnitude of the magnetic flux density is higher than the threshold value; outputting a preceding stored position signal if the magnitude of the magnetic flux density is smaller than or equal to the threshold value; storing the output position signal.