Wheel Sensor Signal Evaluation via Pulse-Width ASO Encoding
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Solution Overview
Problem
Existing electronic brake systems face challenges in efficiently utilizing high-resolution wheel sensors due to hardware complexity and uncertainty in distinguishing between normal and additional wheel sensor protocols, especially at low speeds, which affects the accuracy of wheel position and speed determination.
Innovation Solution
A method involving a first processor unit and a second processor unit, where the first processor evaluates wheel sensor signals and generates pulse-width modulated ASO signals based on the protocol type, allowing the second processor to distinguish between different start pulses and protocol pulses, enabling accurate wheel position and speed determination without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional protocol data is provided with a 21 mA pulse height, then additional sensor resolution is achieved, but hardware complexity increases due to additional pins, timer functions, and decoding requirements
Solution Approach 1:
The existing ASO interface is made multi-functional by using pulse width modulation to encode different protocol types. The same physical interface handles both normal speed pulses and additional position protocols, eliminating the need for separate hardware lines while maintaining full functionality.
Solution Approach 2:
The invention changes the temporal parameter (pulse width) of the ASO signal to encode information about protocol type. Normal protocols generate pulses of one width while additional position protocols generate pulses of another width, allowing the receiver to distinguish between them without additional hardware thresholds.
2Reliability
If a separate ASO line is used for additional protocols, then clear distinction between protocol types is achieved, but additional hardware connections and pins are required
Solution Approach 1:
The invention merges the transmission of normal speed protocols and additional position protocols onto a single ASO interface. By encoding protocol type information in the pulse width, both protocol types share the same physical connection, reducing hardware complexity while maintaining reliable distinction.
Solution Approach 2:
The pulse width acts as an intermediary that carries protocol type information without requiring separate physical channels. The width of the pulse mediates between the two protocol types, allowing the receiver to identify the protocol source through temporal characteristics rather than separate hardware paths.
3Measurement precision
If protocol data is transmitted continuously at high speeds, then complete position information is available, but protocol pulses converge and data is lost
Solution Approach 1:
The system dynamically adapts its operation based on wheel speed conditions. At low speeds where additional position protocols are beneficial, the system can process them without convergence issues. The dynamic nature of pulse width encoding allows flexible handling of different speed regimes without fixed protocol limitations.
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 wheel position and speed determination at low speeds, supporting advanced functions like automated parking and tire pressure monitoring without requiring new hardware, thus being cost-effective and efficient.
Implementation Method 1
A magnetic encoder wheel is located on the wheel of the vehicle. As the wheel rotates, the change in the magnetic field is detected by the sensor
Data Source
AI summary
A method is provided for evaluating wheel sensor signals of a wheel speed sensor where the wheel speed sensor supplies signals that are transmitted using two different protocols. Each protocol comprises a start pulse and a number of data pulses. A first processor unit receives the signals from the sensor and uses the start pulse to determine whether they were transmitted using the first protocol or the second protocol. Depending on the result, the first processor unit signals without a time delay whether a start pulse has been received via an ASO interface of a second processor unit, wherein a variable pulse width is used to indicate whether the start pulse belongs to a data packet that is transmitted with the first protocol or with the second protocol. The second processor provides each incoming ASO signal with a time stamp, so that the speed can be determined.