Adaptive A-D Conversion for Road Surface Identification
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Solution Overview
Problem
Existing road surface condition identification methods face challenges in accurately identifying road surfaces due to varying tire vibration magnitudes, as fixed A-D conversion ranges lead to inadequate frequency analysis and feature extraction, especially when input accelerations exceed the conversion range.
Innovation Solution
A road surface condition identification apparatus that adjusts the A-D conversion range based on vehicle speed, using a tire-associated device with a vibration detector and A-D converter to generate digital signals for accurate frequency analysis and feature extraction, ensuring effective identification of road surfaces regardless of vibration magnitude changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed A-D conversion range is used, then the device complexity is reduced, but the measurement precision deteriorates when input accelerations exceed the conversion range
Solution Approach 1:
The A-D converter's conversion range is made dynamically adjustable based on vehicle speed. The controller selects between a first conversion range for low vehicle speeds and a second conversion range for high vehicle speeds, allowing the system to adapt to varying vibration magnitudes without increasing overall device complexity
Solution Approach 2:
The conversion range parameter of the A-D converter is changed based on vehicle speed conditions. By switching between different conversion range values according to speed thresholds, the system maintains measurement precision across different operating conditions while using a relatively simple device structure
2Adaptability or versatility
If the A-D conversion range is increased to handle large vibrations, then the adaptability improves, but the measurement precision for small vibrations deteriorates
Solution Approach 1:
The system dynamically switches between different conversion ranges based on vehicle speed, which correlates with vibration magnitude. At low speeds where small vibrations occur, a first conversion range with higher precision is used. At high speeds where large vibrations occur, a second conversion range with greater adaptability is used
Solution Approach 2:
The A-D converter's conversion range parameter is changed according to vehicle speed conditions. This parameter change allows the system to optimize between adaptability and precision by selecting appropriate conversion range values matching the expected vibration magnitude at different speeds
3Device complexity
If frequency analysis is performed with inadequate conversion range, then the device complexity is reduced, but the road surface identification accuracy deteriorates
Solution Approach 1:
The system performs preliminary selection of the appropriate conversion range based on vehicle speed before conducting frequency analysis. This preliminary action ensures that the A-D conversion is performed with the correct range, providing accurate digital signals for subsequent frequency analysis and road surface identification
Solution Approach 2:
The controller uses vehicle speed information as feedback to determine the appropriate conversion range for the A-D converter. This feedback mechanism ensures that the conversion range is always appropriate for the current operating conditions, maintaining high identification accuracy without increasing 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 accurate identification of road surface conditions by adapting the A-D conversion range to vehicle speed, improving frequency analysis and feature extraction, thus enhancing the robustness of road surface identification.
Implementation Method 1
a vibration detector unit mounted to a tire of a vehicle to output a detection signal being an analog signal according to magnitude of vibration of the tire
Implementation Method 2
The road surface condition identification apparatus performs A-D conversion of converting the detection signal of the vibration detector into a digital signal having the predetermined number of bits
Data Source
AI summary
A road surface condition identification apparatus for identifying a road surface condition is provided. The road surface condition identification apparatus includes a vibration detector unit configured to output a detection signal being an analog signal according to magnitude of vibration of the tire. For identifying the road surface condition, the road surface condition identification apparatus performs A-D conversion of converting the detection signal of the vibration detector unit into a digital signal. Based on data on vehicle speed, the road surface to condition identification apparatus sets a conversion range of the magnitude of the vibration of the tire used in the AD conversion from the detection signal into the digital signal.