Tire Location Detection Using Geomagnetic Sensor
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Solution Overview
Problem
Existing tire pressure monitoring systems (TPMS) face challenges in accurately determining the location of tires on a vehicle without requiring dual-axis accelerometers, which increase cost and complexity, and struggle with signal strength and phase difference detection at high speeds or on uneven roads.
Innovation Solution
A tire location information transmitting apparatus and method using a geomagnetic sensor to detect magnetic field samples, calculate rotation angles, and determine tire location based on rotational direction and angle, reducing the need for additional components and arithmetic operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dual-axis accelerometers are installed in tires to distinguish left and right positions, then location determination accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical accelerometer-based detection system with a magnetic field-based detection system. The geomagnetic sensor detects changes in magnetic field direction caused by tire rotation, and the control unit calculates rotation angles through logical operations on magnetic field sample information. This substitution eliminates the need for dual-axis accelerometers while achieving the same location determination function.
Solution Approach 2:
The patent introduces the geomagnetic sensor as an intermediary to detect tire rotation indirectly through magnetic field changes rather than directly measuring acceleration. The control unit acts as another intermediary that processes magnetic field samples and calculates rotation angles through logical operations, bridging the gap between magnetic field detection and location determination.
2Adaptability or versatility
If Z-axis accelerometer is installed to detect wheel speed by signal period, then wheel speed detection function is added, but signal offset at high rotation speeds makes period detection difficult and additional circuits are needed
Solution Approach 1:
The patent replaces the accelerometer-based wheel speed detection method with a geomagnetic sensor-based method. Instead of detecting signal periods from accelerometer output, the system samples magnetic field directions at fixed intervals and calculates rotation angles through logical operations, which remains reliable at high rotation speeds without signal offset issues.
Solution Approach 2:
The patent implements periodic sampling of magnetic field information at fixed time intervals to detect tire rotation. This periodic sampling approach, combined with logical operations to calculate rotation angles, provides reliable wheel speed detection without the high-speed signal degradation problems encountered with accelerometer-based methods.
3Reliability
If control device is installed in limited locations such as bumper to avoid RF signal reduction, then signal reception quality is improved, but additional wires and waterproof functions are required increasing cost
Solution Approach 1:
The patent makes the control unit multi-functional by integrating both the tire pressure monitoring functions and the tire location determination functions within the same control unit. This eliminates the need for separate dedicated hardware for location detection, allowing the control unit to be installed in conventional locations without requiring additional wires or special waterproofing arrangements.
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 determination of tire location without additional hardware, reduces power consumption and cost, and improves reliability even on tough road conditions.
Implementation Method 1
a geomagnetic sensor located in a tire of a vehicle to detect a magnetic field
Data Source
AI summary
Provided are an apparatus and method for transmitting information on a location of a tire with information on pressure of the tire. The present disclosure provides logic for calculating rotation angles among a plurality of magnetic field samples obtained from a geomagnetic sensor, calculating rotational directions, and determining the left/right locations of the tire on the basis of the number of times of accumulation of the rotational directions.