Accelerometer Wake-Up Filtering for Impact and Towing Detection
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Solution Overview
Problem
In vehicles, existing systems struggle to accurately differentiate between significant events like impacts and movements such as lifting or towing when the ignition is off, leading to unnecessary battery energy consumption due to false positives in wake-up signals.
Innovation Solution
A system comprising a first controller and an accelerometer that filters acceleration data to distinguish between jerk exceeding a threshold (indicating impacts) and a sum of acceleration measurements exceeding a threshold (indicating movement), minimizing false positives by selectively waking up a second controller only when criteria are met.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second controller is kept awake to detect all acceleration events, then event detection reliability is improved, but battery energy consumption increases
Solution Approach 1:
The patent divides the controller system into two hierarchical levels: a first controller that performs initial acceleration data filtering and event classification, and a second controller that performs detailed event analysis only when triggered. This segmentation allows the system to maintain high detection reliability while consuming less energy, as the power-intensive second controller remains dormant during normal operation and is activated only for significant events.
Solution Approach 2:
The first controller performs preliminary filtering and classification of acceleration data before triggering the second controller. By pre-processing the data and identifying only significant events (such as impacts or towing conditions), the system avoids unnecessary activation of the second controller, thereby reducing energy consumption while maintaining reliable event detection.
2Measurement precision
If the second controller is awakened for every acceleration threshold exceedance, then measurement precision is improved, but false positives increase and energy is wasted
Solution Approach 1:
The first controller performs preliminary analysis of acceleration data to distinguish between significant events (impacts, towing) and normal variations before triggering the second controller. This pre-filtering prevents false positives from unnecessarily activating the second controller, maintaining measurement precision while avoiding energy waste on spurious events.
Solution Approach 2:
The first controller acts as an intermediary between the accelerometer and the second controller, filtering and classifying acceleration data to determine which events warrant second controller activation. This intermediary layer prevents direct triggering of the second controller by every acceleration threshold exceedance, reducing false positives while maintaining detection precision.
3Device complexity
If simple acceleration threshold monitoring is used, then device complexity is reduced, but ability to differentiate event types deteriorates
Solution Approach 1:
The system segments the control functions between two controllers: the first controller handles basic threshold monitoring and initial filtering, while the second controller performs sophisticated event type differentiation. This segmentation allows the overall system to achieve high event differentiation capability without requiring a single overly complex controller, balancing complexity and precision.
Solution Approach 2:
The first controller performs preliminary filtering and classification of acceleration events, organizing data by event type (impact, towing, normal movement) before passing selected events to the second controller. This preliminary action enables the system to differentiate event types effectively while maintaining relatively simple individual controller designs.
Data Source
AI summary
A system includes a first controller including a processor and a memory, and the memory stores instructions executable by the processor to receive first acceleration data from an accelerometer; upon determining that the first acceleration data satisfies a first criterion, transmit a wake-up instruction to a second controller; upon determining that the first acceleration data fails to satisfy the first criterion, instruct the accelerometer to send second acceleration data; and upon determining that the second acceleration data satisfies a second criterion, transmit the wake-up instruction to the second controller. The first criterion includes jerk exceeding a jerk threshold.