Wheel Accelerometer Motion Detection for Low-Power TPMS
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Solution Overview
Problem
Current tire pressure monitoring systems (TPMS) face challenges in efficiently determining the motion status of a vehicle to optimize power consumption, as they require accurate detection of centrifugal and tangential accelerations without precise alignment of accelerometers with these accelerations, leading to potential misjudgment at low speeds and varying conditions.
Innovation Solution
A method using a dual-axis accelerometer mounted on a wheel to collect acceleration values in perpendicular directions, determining the vehicle's motion status by analyzing maximum acceleration change values, allowing the system to adjust power consumption based on whether the vehicle is in motion or stationary, thereby reducing battery drain and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the TPMS operates in normal working mode to collect and send tire pressure data, then the monitoring accuracy is improved, but the power consumption increases significantly
Solution Approach 1:
The TPMS alternates between normal working mode and sleep mode based on vehicle motion status. During normal mode, it collects and transmits tire pressure data with high accuracy. During sleep mode, it reduces power consumption by minimizing operations. The system dynamically switches between these periodic states to balance monitoring accuracy and power consumption.
Solution Approach 2:
The system dynamically adjusts its operating state based on real-time vehicle motion detection. When the vehicle is detected to be in motion, the TPMS transitions to normal working mode for accurate monitoring. When the vehicle is stationary, it transitions to sleep mode to conserve battery power, making the system adaptive to changing conditions.
2Use of energy by moving object
If the TPMS determines vehicle motion status using traditional methods, then the system can adjust power consumption, but the accuracy deteriorates at low speeds and varying conditions
Solution Approach 1:
The acceleration detection is segmented into two independent components: centrifugal acceleration detected along the radial direction of the wheel, and tangential acceleration detected along the tangent direction. By separating these two acceleration components and processing them independently, the system achieves more accurate motion status detection across all vehicle speeds and conditions.
3Measurement precision
If the accelerometer is precisely aligned with centrifugal and tangential acceleration directions, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The system automatically identifies and adapts to the wheel's radial and tangent directions through signal processing algorithms without requiring manual or precise physical alignment of the accelerometer. The accelerometer naturally detects acceleration components, and the system processes these signals to extract centrifugal and tangential acceleration information, making the device self-configuring and reducing installation 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
This approach effectively determines the vehicle's motion status with reduced accuracy requirements for the accelerometer, enabling efficient power management and accurate monitoring, even at low speeds, by comparing acceleration change values without needing precise alignment with centrifugal and tangential acceleration directions.
Implementation Method 1
obtaining N acceleration values in a first axial direction collected from N times sampling within a preset time period through an accelerometer mounted on a wheel; and obtaining N acceleration values in a second axial direction collected from N times sampling within the preset time period through the accelerometer mounted on the wheel
Data Source
Figure 1~2a
Figure 2b~2c
Figure 3~4
AI summary
The present disclosure provides a method for monitoring a motion status of a vehicle and a related chip, a device, and a system. The method includes: obtaining (S11) N acceleration values in a first axial direction collected from N times sampling and a maximum acceleration change value within a preset time period; and obtaining (S11) N acceleration values in a second axial direction collected from N times sampling and a maximum acceleration change value within the preset time period; determining (S12) whether the vehicle is in motion or in a first stationary state based on the acceleration values in the first and second axial direction; and in response to the vehicle being in the first stationary state, further determining (S13) whether the vehicle is in motion or in a second stationary state based on the maximum acceleration change values in the first and second axial direction.