TPMS Tire Position Learning Using UWB Distance Measurement
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Solution Overview
Problem
Conventional tire position learning methods in TPMS face issues such as increased costs, complex wiring, and position learning errors at high speeds due to RF signal reflection and phase measurement errors, particularly in LF initiator and Loc on Sync methods.
Innovation Solution
The implementation of ultra-wide band (UWB) technology for tire position learning, utilizing tire module units to transmit pressure information via UWB signals and vehicle module units to calculate tire positions using distance information from multiple UWB communication units, enabling accurate position determination through trigonometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LF initiators are installed in four places in tire adjacent spaces inside the vehicle to learn tire positions, then tire position learning can be achieved, but costs increase, wiring becomes complicated, and fuel efficiency deteriorates due to increased vehicle weight
Solution Approach 1:
The patent extracts the position learning function from the complex LF initiator system and implements it using only the existing wheel units with UWB transceivers. The vehicle ECU uses UWB signals from the wheel units to calculate positions trigonometrically, eliminating the need for separate LF initiators and their associated wiring infrastructure.
Solution Approach 2:
The wheel units are given dual functionality: they continue to monitor tire pressure while also serving as position transmitters via UWB signals. This eliminates the need for dedicated position learning devices (LF initiators) and reduces system complexity while maintaining position learning capability.
2Ease of operation
If RF signals are used for tire pressure monitoring and position learning, then wireless communication can be achieved, but signal reflection and fading cause the electronic control unit to be unable to receive signals reliably
Solution Approach 1:
The patent changes the fundamental parameter of the wireless signal from RF frequency to UWB frequency. UWB signals operate at significantly higher frequencies with extremely short pulse durations, which fundamentally alters how the signal propagates and interacts with the vehicle environment, avoiding the reflection and fading problems that plague traditional RF systems.
3Measurement precision
If the Loc on Sync method is used where each wheel unit transmits RF signal only at a specific phase, then tire position learning can be achieved, but position learning mistakes occur when the vehicle is travelling at speeds of 130 km/h or more due to phase measurement errors
Solution Approach 1:
The patent replaces the mechanical/phase-based position determination method with a signal-based UWB time-of-flight measurement system. Instead of relying on wheel rotation phase detection that fails at high speeds, the system uses electromagnetic signal propagation time measurements that remain accurate regardless of vehicle speed.
4Measurement precision
If four LFi must be additionally installed on the vehicle for tire position learning, then tire position learning can be achieved, but costs increase and vehicle weight increases leading to deterioration in fuel efficiency
Solution Approach 1:
The wheel units serve themselves by performing both tire pressure monitoring and position transmission functions. The existing wheel unit infrastructure is leveraged to provide position learning capability without requiring additional weight-bearing components, thereby maintaining fuel efficiency while achieving position accuracy.
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 provides a cost-effective and accurate method for learning tire positions, reducing errors and complexity, while maintaining stability in signal measurement even at high speeds.
Implementation Method 1
a plurality of tire module units mounted on a tire of the vehicle respectively so as to detect pressure information and transmit same via an ultra-wide band (UWB) signal
Implementation Method 2
the control unit calculates and learns the position of each tire by using distance information measured in a plurality of the vehicle UWB communication units, by using UWB signals respectively transmitted from a plurality of the tire module units
Data Source
AI summary
A tire position learning apparatus for a tire pressure monitoring system, comprising: a plurality of tire module units, each of which is respectively mounted on a tire of the vehicle to detect pressure information and transmit same via an ultra-wide band (UWB) signal; and a vehicle module unit which communicates with the plurality of tire module units via UWB signals so as to detect the individual tire pressures and any tire in which low pressure has occurred.