Magnetic Field Sensor Orientation Independent Speed Measurement
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Solution Overview
Problem
Differential magnetic field sensors are orientation-dependent, requiring precise alignment with the target for optimal performance, which can be impractical in applications where alignment control is not feasible, leading to reduced peak-to-peak signal and suboptimal speed and direction measurement.
Innovation Solution
A magnetic field sensor system utilizing three spaced magnetic field sensing elements configured in multiple differential channels, with a combining element and control circuitry to generate a combined signal that is independent of the sensor's installation angle relative to the target, allowing for orientation-independent speed and direction measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a differential magnetic field sensor is used to measure speed and direction, then the sensor is relatively immune to interference, but the sensor becomes orientation dependent and requires precise alignment with the target for optimum performance
Solution Approach 1:
The sensor divides the measurement function into three separate sensing elements arranged in multiple differential channels (first, second, and third channels), each sensitive to different spatial components of the magnetic field. This segmentation allows the system to reconstruct the complete magnetic field vector information without requiring precise alignment, as each element contributes partial information that is combined to achieve orientation-independent measurement.
Solution Approach 2:
The invention transitions from a single-axis differential measurement to a multi-dimensional measurement system by adding sensing elements in different spatial orientations. The three sensing elements are positioned to detect magnetic field components along different axes, and the control circuitry processes these multi-dimensional signals to generate orientation-independent speed and direction information, effectively adding spatial dimensions to the measurement capability.
2Ease of operation
If the sensing elements are misaligned relative to the target profile, then the installation is easier, but the peak-to-peak signal is reduced resulting in suboptimal measurement performance
Solution Approach 1:
The system changes the measurement parameters by processing multiple differential channel signals (first, second, and third channel signals) through the control circuitry to generate a composite measurement output. Instead of relying on a single high-amplitude signal that requires precise alignment, the system combines signals from multiple channels with different spatial sensitivities, changing the measurement approach from amplitude-dependent to orientation-independent parameter extraction.
Solution Approach 2:
The invention creates redundant measurement copies through multiple differential channels, where each channel provides a copy of the magnetic field information from a different spatial perspective. The control circuitry processes these redundant copies to reconstruct the complete measurement information, allowing the system to tolerate misalignment in any single channel while maintaining overall measurement accuracy.
3Measurement precision
If multiple sensing elements are used to provide orientation-independent measurement, then the measurement accuracy is improved, but the device complexity increases
Solution Approach 1:
The invention merges the functions of multiple sensing elements and multiple differential channels into a unified measurement system. The control circuitry combines the first, second, and third channel signals to generate a single orientation-independent output, merging the complexity of multiple elements into a coordinated system that achieves orientation independence while providing a simplified interface for speed and direction measurement.
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 speed and direction sensing of a target's motion without the need for precise sensor-target alignment, simplifying installation and maintenance while maintaining signal integrity across varying installation angles.
Implementation Method 1
The magnetic field associated with the target profile is sensed by a magnetic field sensing element, such as Hall element or magnetoresistive (MR) element
Implementation Method 2
The magnetic field associated with the target profile is sensed by a magnetic field sensing element, such as Hall element or magnetoresistive (MR) element
Implementation Method 3
a first differential channel comprising a first pair of the first, second, and third magnetic field sensing elements and configured to provide a first channel signal based on a difference between the magnetic field signals provided by the first pair of magnetic field sensing elements
Data Source
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AI summary
A magnetic field sensor that provides target speed and direction detection that is independent of sensor-to-target orientation includes at least three differential channels, each responsive to a pair of magnetic field sensing elements to generate a respective magnetic field channel signal. A combining element is configured to generate a combined signal based on the first, second, and third magnetic field channel signals and control circuitry responsive to the combined signal and to at least one of the first, second, and third magnetic field channel signals generates a sensor output signal that indicative of target speed and direction.