SENT Sensor Signal Latency Compensation via Calibration Pulse
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Solution Overview
Problem
Existing sensor systems face variable latency issues due to asynchronous data transmission and processing delays, which affect the accuracy and timeliness of sensor data reporting, particularly in vehicle control systems using protocols like SENT, leading to instability in control systems.
Innovation Solution
A sensing system that generates a calibration pulse and adjusts sensor data based on the time difference between the pulse and data request, using prior samples to determine the rate of change and extrapolate more accurate real-time data, thereby compensating for variable latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If asynchronous data transmission is used in SENT protocol, then device complexity is reduced and ease of operation is improved, but measurement precision deteriorates due to variable latency
Solution Approach 1:
The system performs preliminary actions by capturing multiple prior sensor data samples before the current reading is needed. These preliminary samples are stored and used to calculate the rate of change, enabling the system to compensate for latency without requiring real-time precise measurements.
Solution Approach 2:
The system implements feedback by calculating the rate of change from prior samples and using this feedback to adjust the current sensor reading. This closed-loop approach compensates for the variable latency introduced by asynchronous transmission, improving measurement precision while maintaining ease of operation.
2Productivity
If variable pulse width transmission is used, then information transmission efficiency is improved, but stability deteriorates due to variable latency affecting control systems
Solution Approach 1:
The system performs preliminary actions by capturing multiple prior sensor data samples before the current reading is needed. These preliminary samples are stored and used to calculate the rate of change, enabling the system to compensate for latency without requiring real-time precise measurements.
Solution Approach 2:
The system changes parameters by adjusting the sensor reading based on the calculated rate of change and age of data. This dynamic parameter adjustment compensates for variable latency, maintaining control system stability while preserving the efficiency benefits of variable pulse width transmission.
3Device complexity
If processing delays occur in CPU or ECM, then device complexity is reduced, but loss of time increases affecting real-time control accuracy
Solution Approach 1:
The system performs preliminary actions by capturing multiple prior sensor data samples before the current reading is needed. These preliminary samples are stored and used to calculate the rate of change, enabling the system to compensate for latency without requiring real-time precise measurements.
Solution Approach 2:
The system practices self-service by autonomously calculating the age of sensor data and compensating for processing delays using the rate of change derived from prior samples. This self-compensation mechanism eliminates the need for complex external timing synchronization, reducing device complexity while minimizing time loss.
Data Source
AI summary
A sensing system comprises a sensor that generates a calibration pulse and first sensor data and that transmits the first sensor data using a variable pulse width. A control module determines an age of the first sensor data based on a time difference between the calibration pulse and when the sensor data is at least one of received and used, that determines a rate of change of the sensor data based on N prior sensor data samples and the first sensor data samples, and that adjusts the first sensor data based on the time difference and the rate of change.