Rearview Mirror Positioning Using Electromagnets and Magnetometers
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Solution Overview
Problem
Existing vehicular rearview assemblies face limitations in determining the accurate orientation and location of multi-jointed mounts due to the use of permanent magnets and single-axis magnetometers, which are not adaptable to complex configurations and cannot account for background magnetic disturbances.
Innovation Solution
A rearview assembly utilizing first and second electromagnets positioned within the mount or housing, along with a magnetic field sensor, and a processor that selectively activates these electromagnets to generate magnetic fields for determining the rotational position of the main unit about three perpendicular axes, while compensating for ambient magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If permanent magnets and single-axis magnetometers are used, then the structure is simple, but the measurement precision and adaptability to multi-jointed mounts are insufficient
Solution Approach 1:
The patent replaces permanent magnets with electromagnets that can be selectively activated. This substitution allows for controlled magnetic field generation only when needed for measurement, reducing constant magnetic interference while maintaining measurement precision. The electromagnets are activated in sequence to determine rotational positions about multiple axes without requiring a permanently active magnetic field throughout the system.
Solution Approach 2:
The patent changes the magnetic field parameters by selectively activating different electromagnets based on which rotational axis needs to be measured. Instead of having a constant magnetic field configuration, the system dynamically adjusts which electromagnets are active, creating magnetic fields only in the directions needed for current measurements, thereby improving precision while managing system complexity.
2Adaptability or versatility
If magnets and sensors are placed in a ball-socket joint or on the electronic board, then the device complexity is reduced, but the adaptability to multi-jointed mounts and measurement accuracy are limited
Solution Approach 1:
The patent divides the magnetic field generation function into multiple separate electromagnets positioned at different locations within the housing. Each electromagnet can be independently activated to generate magnetic fields for measuring rotational positions about specific axes. This segmentation allows the system to adapt to multi-jointed mount configurations while maintaining measurement accuracy through selective activation of appropriate electromagnets.
3Measurement precision
If background magnetic disturbances are not accounted for, then the system operation is simpler, but the measurement precision deteriorates due to magnetic interference
Solution Approach 1:
The patent incorporates a processor that receives magnetic field information from the magnetic field sensor and actively compensates for background magnetic disturbances. The processor analyzes the magnetic field measurements and corrects for interference from permanent magnets and ambient magnetic fields, providing accurate rotational position determination despite the presence of magnetic disturbances. This feedback mechanism maintains measurement precision while managing the complexity through intelligent processing.
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 precise and adaptable positioning of the rearview assembly by accurately determining the rotational and translational position of the main unit relative to the mount, enhancing the accuracy of driver monitoring systems and display units.
Implementation Method 1
First and second electromagnets are positioned within one of the mount or the housing in mutually spaced apart first locations
Implementation Method 2
a first magnetic field sensor is positioned within the other of the housing and the mount... receives first magnetic field information related to the first magnetic field and second magnetic field information related to the second magnetic field
Data Source
AI summary
A rearview assembly includes a mount and a main unit coupled to the mount such that the main unit is articulable on the mount by rotation about three perpendicular axes. First and second electromagnets are positioned within one of the mount or the housing and a first magnetic field sensor is positioned within the other of the housing and the mount. A processor selectively activates the first and second electromagnets for separate generation of a first magnetic field and a second magnetic field. The processor receives first magnetic field information related to the first magnetic field and second magnetic field information related to the second magnetic field from the first magnetic field sensor and determines a rotational position of the main unit in relation to the mount about each of the three perpendicular axes based on the first and second magnetic field information.