Wheel Position Detector Using Gear Tooth Verification
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Solution Overview
Problem
Existing wheel position detection systems for tire inflation pressure monitoring face challenges in accurately and efficiently specifying wheel positions, particularly when tire rotation occurs or when transmitters from other vehicles are mistakenly registered, leading to incorrect ID information.
Innovation Solution
A wheel position detector system that uses transmitters with unique identification information, acceleration sensors to determine the angle of the transmitter relative to the wheel, and wheel speed sensors to acquire gear information, setting variation allowable ranges to exclude incorrect wheel candidates and ensure accurate registration of wheel positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the receiver pre-registers ID information about each transmitter in association with each wheel position, then the wheel position can be identified, but when tire rotation is performed, the receiver needs to re-register the ID information, which increases the loss of time
Solution Approach 1:
The system performs preliminary wheel position detection when the vehicle is stationary before tire rotation occurs. The receiver stores the detected wheel positions and their associated transmitter ID information. When tire rotation happens, the pre-detected positions are used as reference to quickly identify new wheel positions by comparing with post-rotation detection results, eliminating the need for complete re-registration
Solution Approach 2:
The system continuously monitors wheel positions and compares detected positions with previously stored reference positions. When changes are detected (indicating tire rotation), the system uses feedback from the comparison to automatically update the wheel position database without requiring manual re-registration, maintaining accurate association between transmitters and wheel positions
2Productivity
If the receiver receives wireless signals from transmitters of other vehicles during wheel position detection, then signal reception is active, but there is a possibility that the receiver incorrectly registers the ID information of transmitters from other vehicles, which decreases the reliability
Solution Approach 1:
The system applies different processing rules to different received signals based on their characteristics. For signals from the subject vehicle's own transmitters, the system performs detailed verification including checking whether the signal source matches expected wheel positions. For signals from other vehicles, the system applies filtering criteria that reject registration based on signal strength thresholds, temporal patterns, and positional consistency checks, ensuring only valid signals are registered
Solution Approach 2:
The system introduces an intermediate verification step between signal reception and registration. Before registering a transmitter ID, the system checks whether the received signal corresponds to a known wheel position of the subject vehicle by comparing detected positions with stored reference data. This intermediary check prevents incorrect registration of foreign transmitters while allowing efficient reception of valid signals
3Extent of automation
If the system uses acceleration detection signals from the acceleration sensor to determine wheel rotation position, then the wheel position can be detected, but the detection may be inaccurate when the vehicle is stationary or moving at constant speed, which decreases the measurement precision
Solution Approach 1:
The system merges multiple detection methods to determine wheel position. The acceleration sensor detects wheel rotation by measuring gravitational component changes, while the wheel speed sensor detects rotation through gear tooth passage. The system combines information from both sensors, using the acceleration sensor for dynamic position tracking during motion and the wheel speed sensor for precise position verification, compensating for the weaknesses of each individual method
Solution Approach 2:
The system uses the acceleration sensor continuously to monitor wheel position even when full precision is not required (such as during steady-state cruising). The wheel speed sensor is activated selectively when precise position determination is needed (such as during acceleration, deceleration, or when verifying position changes). This partial use of detection resources maintains precision when needed while reducing overall system complexity
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 fast and accurate specification of wheel positions, preventing incorrect registration of transmitters from other vehicles and ensuring precise tire inflation pressure monitoring.
Implementation Method 1
an acceleration sensor for outputting an acceleration detection signal indicative of acceleration having a gravity acceleration component varying with a rotation of the corresponding wheel
Implementation Method 2
The gear includes teeth having electrical conductivity and intermediate portions alternately arranged with the teeth along an outer periphery of the gear so that a magnetic resistance of the gear changes along the outer periphery
Implementation Method 3
transmitting a detection result from the pressure sensor via the transmitter, and receiving the detection result by a receiver mounted on the vehicle
Data Source
AI summary
In a wheel position detector for a vehicle, a transmitter on each wheel repeatedly transmits a data frame containing identification information when an angle of the transmitter reaches a transmission angle. A receiver for receiving the frame is mounted on a body of a vehicle and performs wheel position detection based on the frame to specify a target wheel from which the frame is transmitted. The receiver acquires a tooth position of a gear rotating with a corresponding wheel when receiving the frame and sets a variation allowable range based on the tooth position. The receiver specifies the target wheel by determining whether the tooth position falls within the variation allowable range a predetermined number of times in a row.