Tire Pressure Sensor Wireless Positioning via Broadcast Timing
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Solution Overview
Problem
Existing tire pressure monitoring systems face challenges in accurately determining the wheel position without relying on a return channel or trigger transmitter, particularly at low speeds, and require complex antenna configurations to compensate for gravity's influence on acceleration sensors.
Innovation Solution
The method employs motion detection using Z or X sensors to determine rotational frequency, allowing for a speed-independent switching threshold, and transmits data in clustered bursts during specific vehicle states, eliminating the need for a return channel and reducing energy consumption by shortening telegrams during starting-off phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a return channel or trigger transmitter is used to determine wheel position, then wheel position determination accuracy is improved, but device complexity increases
Solution Approach 1:
The electronic module in the wheel determines its own position by analyzing the arrival times of broadcast telegrams at different receiving antennas, without requiring any active participation or return channel from the control device. The system serves itself by using the natural propagation characteristics of the broadcast signals to encode position information.
Solution Approach 2:
The broadcast telegrams serve as an intermediary carrier that indirectly conveys position information. By analyzing the timing characteristics of these telegrams received at multiple antennas, the system determines wheel position without requiring a direct communication channel between the wheel and control device.
2Reliability
If data are transmitted at short measurement intervals when the vehicle is moving, then measurement reliability is improved, but energy consumption increases
Solution Approach 1:
The measurement and transmission intervals are dynamically adjusted based on vehicle motion state. During motion, the system increases measurement frequency to improve reliability, while during standstill, it reduces frequency to conserve battery energy, optimizing the trade-off between reliability and energy consumption.
Solution Approach 2:
The system employs periodic measurement cycles that are modulated according to vehicle state. Rather than continuous transmission, measurements are taken at regular intervals that are adjusted based on whether the vehicle is moving or stationary, reducing overall energy consumption while maintaining necessary monitoring reliability.
3Use of energy by moving object
If the measurement cycles are influenced depending on vehicle motion, then energy consumption is reduced, but measurement precision at low speeds deteriorates
Solution Approach 1:
The system changes the parameter used for switching threshold determination from acceleration-based to arrival time difference-based measurements. This parameter change enables accurate wheel position determination at low speeds where acceleration signals are weak, while still maintaining energy-efficient measurement cycles.
Solution Approach 2:
The system replaces mechanical acceleration sensor-based detection with a signal-processing-based arrival time difference method. This substitution eliminates the need for complex mechanical sensing and allows accurate low-speed detection through temporal analysis of broadcast telegrams rather than force-based measurements.
4Measurement precision
If multiple receiving antennas are used to determine wheel position, then position accuracy is improved, but device complexity increases
Solution Approach 1:
The multiple receiving antennas serve multiple functions: they simultaneously enable wheel position determination, provide redundancy for reliable signal reception, and allow the system to operate without requiring a return channel or trigger transmitter, thus achieving multi-functionality with a single component set.
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 wheel position determination without a return channel, reduces energy usage, and ensures reliable data transmission with minimal data loss, even at low speeds, by using rotational frequency to compensate for gravity's influence and transmitting data in optimized bursts.
Implementation Method 1
an electronic module which is disposed in one of the wheels and transmits data wirelessly to the control device
Implementation Method 2
a method that uses a duty cycle of 50% LF at a standstill and 100% during driving... a method for detecting the transition between standstill and driving is known that makes use of the deflection of an acceleration sensor. Centrifugal force determines the point in time at which switching occurs
Implementation Method 3
Centrifugal force determines the point in time at which switching occurs
Data Source
AI summary
A method is described for monitoring and wirelessly signaling data that contains information on the pressure states prevailing in tires of wheels. In the method, electronic modules that are arranged in the wheels wirelessly transmit the data to a control device which is arranged in the vehicle. No data is transmitted during a first mode associated with a standstill state of the vehicle, while the respective electronic module transmits the data to the control device in the form of telegrams during at least one other mode associated with another state of the vehicle, the transition from a first mode into at least one other mode being determined by means of at least one acceleration sensor.