3D Hall Sensor for Omnidirectional Speed and Direction Detection
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Solution Overview
Problem
Existing magnetic field sensors for commercial vehicles require complex calculations and consume significant computing time to determine the direction and speed of rotating objects, and they lack accuracy due to the need for axial displacement.
Innovation Solution
A magnetic field sensor system comprising a pole wheel with magnetically encoded teeth and gaps, combined with a chip containing three linearly independent Hall sensors (lateral and vertical) that generate differential signals to calculate rotational speed and direction, reducing the need for three difference channels and enabling accurate measurements regardless of sensor position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three difference channels are calculated to determine rotational speed and direction, then measurement capability is improved, but computing time and complexity increase
Solution Approach 1:
The patent extracts and utilizes only the essential components needed for measurement. By using three linearly independent magnetic field measuring elements with normal vectors that are linearly independent, the system obtains sufficient information for speed and direction determination without requiring complex three-channel difference calculations, thus reducing computing time while maintaining measurement precision.
Solution Approach 2:
The patent changes the parameter of measurement from requiring three difference channels to using the amplitudes of magnetic field signals from three linearly independent measuring elements. This parameter change simplifies the calculation process while preserving the ability to determine both rotational speed and direction accurately.
2Adaptability or versatility
If axial displacement is required for sensor positioning, then adaptability to different positions is improved, but measurement accuracy deteriorates
Solution Approach 1:
The patent creates a universal sensor system that can accurately measure rotational speed and direction regardless of the sensor's axial position. The three linearly independent magnetic field measuring elements with linearly independent normal vectors enable the sensor to function correctly at various positions, making the system adaptable while maintaining precision.
Solution Approach 2:
The patent moves from a two-dimensional measurement approach to a three-dimensional approach by using three magnetic field measuring elements whose normal vectors are linearly independent. This dimensional expansion allows the sensor to compensate for axial displacement and maintain measurement accuracy across different positions.
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 provides rapid and accurate determination of rotational speed and direction by utilizing two differential signals, minimizing computing time and ensuring consistent measurement accuracy even with varying sensor positions, and offering diagnostic capabilities like air gap detection.
Implementation Method 1
Hall sensors are used in particular here, which measure the magnetic field emanating from a rotating object at three points
Data Source
Figure 1a~1c
Figure 2a
Figure 2b
AI summary
The present invention relates to a magnetic field sensor (1) which is designed to determine the rotational speed and rotational direction of a rotating object (20) which either generates a rotating magnetic field itself or deflects an existing magnetic field accordingly. For this purpose, a chip (2) having at least three magnetic field measuring elements (2a, 2b, 2c) in the form of a 3D Hall sensor is used. Such magnetic field sensors (1) are used in particular in commercial vehicles. A normal direction in relation to the tangential plane of the rotating element defines a z-direction. A differential signal is formed from the signal from a sensor element having a sensitivity in the z-direction together with the signal from a further sensor element. The two resulting differential signals have a phase shift from which the rotational direction can be determined. A generated output signal contains information about both the rotational direction and the speed.