Wheel Localizer Using Rotational Frequency and Acceleration
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Solution Overview
Problem
Existing Tire Pressure Monitoring Systems (TPMS) face challenges in efficiently and economically determining the position of wheels on a vehicle after tire replacement or reassignment, particularly due to the complexity of wireless signal propagation and the need for multiple Low-Frequency initializers or ABS system signals.
Innovation Solution
The system utilizes rotational frequencies of wheels and associated accelerations to determine wheel positions, allowing for localization without relying on known positions or ABS signals, using sensors like acceleration sensors, energy harvesters, and optical sensors to derive relationships between wheel frequencies and assign positions based on geometry and movement states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple Low-Frequency initializers are used for wheel position initialization, then wheel position determination accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple LF-initializers into a single shared initializer that can initialize multiple wheel sensors. This single initializer transmits identification signals that are received by multiple wheel position detectors, eliminating the need for separate initializers at each wheel location and reducing overall system complexity while maintaining initialization accuracy
Solution Approach 2:
The single LF-initializer is designed to serve multiple functions by being able to initialize sensors at different wheel positions. It can transmit identification signals that are detected by multiple wheel position detectors, making one initializer universal for determining positions of multiple wheels, thus reducing the total number of initializers needed
2Measurement precision
If ABS system signals are used to determine wheel rotational frequencies, then wheel position determination accuracy is improved, but adaptability to after-market installations deteriorates
Solution Approach 1:
The system uses the wheel sensors themselves to generate and transmit identification signals without requiring external ABS system signals. Each wheel position detector independently determines its position by receiving identification signals from the LF-initializer, making the system self-sufficient and adaptable to after-market installations where ABS signals may not be available
Solution Approach 2:
The patent extracts the wheel position determination function from the ABS system by using separate LF-initializers and wheel position detectors that operate independently. This separation allows the TPMS to determine wheel positions without relying on ABS system signals, improving adaptability for after-market installations while maintaining positioning accuracy
3Measurement precision
If asymmetric LF-transmitter positions are used to distinguish wheel locations, then wheel position determination is improved, but device complexity and installation difficulty increase
Solution Approach 1:
The patent employs asymmetric positioning of the single LF-initializer relative to the vehicle wheels, placing it closer to certain wheels than others. This asymmetric position creates distinct signal strength patterns that allow the system to differentiate between front and rear wheels, achieving position determination accuracy while using only one initializer
Solution Approach 2:
The system utilizes changes in signal reception parameters (signal strength, timing) based on the asymmetric position of the LF-initializer to determine wheel locations. By measuring and comparing these parameter variations across different wheel detectors, the system achieves accurate position determination without requiring multiple symmetrically placed transmitters
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 enables accurate and cost-effective wheel position determination on vehicles, suitable for both original equipment and after-market installations, without the need for extensive infrastructure or additional signal sources, improving efficiency and reducing installation complexity.
Implementation Method 1
acceleration sensors determining the rotational direction of the wheels to distinguish left and right wheels
Data Source
AI summary
A device, a system, a method and a computer program for locating a plurality of positions of a plurality of wheels on a vehicle disclosed. The device includes an input to obtain information related to a position of one wheel from the plurality of wheels, and a detector to obtain information related to rotational frequencies of the one wheel and of at least one other wheel of the plurality of wheels. The device further includes a locator coupled to the input and to the detector. The locator is configured to determine information related to the position of the at least one other wheel based on the information related to the position of the one wheel and based on the information related to the rotational frequencies. Additionally or alternatively, the device may include one or more inputs to obtain information related to rotational frequencies of the plurality of wheels and information related to accelerations at the plurality of wheels. The device may further include a locator coupled to the one or more inputs. The locator is configured to determine the plurality of positions of the plurality of wheels based on the information related to the rotational frequencies of the plurality of wheels and based on the information related to the accelerations at the plurality of wheels.