Vehicle Data Recorder Adaptive Sampling
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Solution Overview
Problem
Current data recording apparatuses for vehicles face inefficiencies in recording data from multiple sensors due to uniform sampling intervals, leading to excessive data recording, increased CPU load, and costs, as well as challenges in accurately determining the time of event occurrence during post-analysis.
Innovation Solution
A data recording apparatus that sets sampling frequencies based on the frequency range of each sensor's output signal, using counters to record data at predetermined intervals and conditions, allowing for accurate calculation of the time lag between event occurrence and sampling timing, thereby reducing unnecessary data recording and CPU load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sampling interval is set to the fastest sampling interval based on the frequency range of output signal of each sensor, then the output signal can be reproduced accurately, but sensors capable of reproducing output signals at the sampling interval obtain excessive data, resulting in increase in recording capacity and costs
Solution Approach 1:
The patent segments the recording system into multiple recording units, each dedicated to a specific sensor type. Each recording unit has its own counter that operates at the optimal sampling frequency for that particular sensor, allowing different sensors to be sampled at different rates according to their frequency characteristics.
Solution Approach 2:
The patent implements dynamic sampling where the sampling frequency for each sensor is adjusted according to its specific frequency range. The controller dynamically configures counters to match the optimal sampling frequency for each sensor type, rather than using a fixed uniform sampling rate for all sensors.
2Measurement precision
If the sampling interval is set to the fastest sampling interval, then high-frequency output signals can be reproduced accurately, but a load on CPU is increased by conducting unnecessary sampling and a high-speed CPU is required, also resulting in rise in costs
Solution Approach 1:
The patent divides the CPU processing into separate processing paths for different sensor types. Each sensor type has its own dedicated counter and processing logic, allowing the CPU to operate at lower speeds by processing each sensor type independently at its optimal sampling rate rather than processing all sensors at the highest required rate.
Solution Approach 2:
The patent changes the sampling frequency parameter for each sensor based on its specific frequency characteristics. By matching the sampling frequency to the sensor's frequency range, the system achieves accurate reproduction without requiring high-speed CPU processing for all sensors.
3Ease of manufacture
If uniform sampling intervals are used for all sensors, then the recording system is simple to implement, but excessive data is recorded and costs increase
Solution Approach 1:
The patent segments the recording system into multiple independent recording units, each handling a specific sensor type with its own counter and processing logic. This segmentation allows each unit to be configured independently for optimal performance while maintaining overall system simplicity through modular architecture.
Data Source
AI summary
A data recording apparatus for a vehicle includes a vehicle state detecting sensor configured to detect a state of the vehicle at the time of traveling and to provide an output value, a recorder configured to record the output value of the vehicle state detecting sensor, and a controller configured to record the output value of the vehicle state detecting sensor into the recorder; the controller has a counter configured to perform counting repeatedly according to a counting frequency and a counting range which are set based on a frequency band of an output signal of the vehicle state detecting sensor, a count value recorder configured to record a count value of the counter, and a judging section configured to judge a state of the output value of the vehicle state detecting sensor.