Angular Position Detection Using Orthogonal Hall Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining the instantaneous angular position of a motor vehicle headlamp, particularly those using Hall effect sensors, are costly, complex, and prone to inaccuracies due to external influences like temperature and vibrations, and cause unwanted movement during initialization, potentially dazzling oncoming drivers and affecting availability.
Innovation Solution
A method utilizing at least two Hall effect sensors measuring the local magnetic field along orthogonal axes, with an electronic processing unit calculating the angular position by weighting measurement signals with correction coefficients to ensure linear proportionality throughout the headlamp's travel range, and a ferromagnetic element radially offset to provide a unique magnetic field direction for each angular position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single Hall effect sensor is used to measure the magnetic field intensity, then the measurement is simple and low-cost, but the measurement precision is insufficient due to external influences like temperature and vibrations
Solution Approach 1:
The patent divides the single measurement task into two independent measurements by using two orthogonal Hall effect sensors. Each sensor measures the magnetic field component along its specific axis, and the final angular position is derived by combining both measurements. This segmentation allows each sensor to operate in a optimized direction while collectively providing precise angular measurement that compensates for external disturbances.
Solution Approach 2:
The patent transitions from one-dimensional measurement (single sensor measuring total field intensity) to two-dimensional measurement (two sensors measuring orthogonal components). By measuring the magnetic field vector components along two perpendicular axes and calculating the arctangent of their ratio, the system achieves full angular measurement capability with improved precision and immunity to external influences.
2Manufacturing precision
If the actuator is brought against the stops during initialization to establish reference position, then the reference angular position is accurately defined, but unwanted movement of the headlight occurs which may dazzle oncoming drivers
Solution Approach 1:
The patent replaces the mechanical stop-based reference establishment method with a magnetic field-based reference detection method. The Hall effect sensors detect the magnetic field orientation to determine the reference angular position without requiring mechanical contact or movement against stops. This substitution eliminates the harmful mechanical initialization movement while maintaining accurate reference position establishment.
Solution Approach 2:
The magnetic field sensor system automatically detects and establishes the reference angular position through electronic measurement of the magnetic field vector, without requiring external mechanical intervention or manual positioning. The system self-calibrates by detecting the magnetic north direction or predefined magnetic reference, eliminating the need for driver-present initialization procedures.
3Measurement precision
If the actuator traverses the entire stroke step by step to obtain reference angular position, then the headlight can be positioned accurately, but the initialization time is significantly increased reducing projector availability
Solution Approach 1:
The patent performs preliminary action by pre-establishing the reference angular position through magnetic field detection during manufacturing or system setup. The magnetic reference direction is stored in memory, allowing the actuator to jump directly to the correct angular position without traversing the entire stroke during normal operation. This preliminary establishment of reference eliminates time-consuming initialization sequences.
Solution Approach 2:
The patent replaces the mechanical step-by-step traversal method with electronic angular position calculation based on magnetic field vector measurements. The Hall effect sensors continuously provide angular position data through mathematical calculation (arctangent function), allowing instantaneous determination of headlight orientation without mechanical probing or incremental movement.
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 approach allows for precise and cost-effective determination of the headlamp's angular position across its entire range, minimizing unwanted movement and improving availability by canceling out measurement errors through signal ratio calculations.
Implementation Method 1
at least first measuring means which are capable of emitting a first electrical measuring signal which is representative of the intensity of the local magnetic field projected onto a first axis
Data Source
Figure 1~3
Figure 4~5
AI summary
The invention relates to a method for determining the angular position of a pivoting projector (10) by means of a measuring device comprising a ferromagnetic element (32) that emits a magnetic field (B), first measuring means (34A) of the local magnetic field (B) projected onto a first axis, the ferromagnetic element (32) being pivotally mounted relative to the first measuring means (34A), and an electronic processing unit (35), the method comprising a measurement step, and a second processing step during which the electronic processing unit (35) calculates the angular position of the projector, characterized in that during the measurement step, the intensity of the local magnetic field (B) is measured projected onto a second measuring axis (M2) orthogonal to the first measuring axis (M1), and in that during the second processing step,The electronic processing unit (35) calculates a representative value of the angle of the local magnetic field (B) with respect to the first measurement axis (M1). The invention also relates to a measuring device for implementing the method according to the invention.