Dual-Cyclic Buffer Black Box for Power-Loss Crash Data Capture
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Solution Overview
Problem
Autonomous driving vehicles face challenges in recording and retaining raw sensor data, especially during power losses, as uncompressed data is expensive to store and volatile memory loses data in such events, while existing solutions are costly and inefficient.
Innovation Solution
Implementing two cyclic buffers, one in volatile memory for raw data and another in non-volatile memory for compressed data, allowing for data retention during power disruptions and efficient storage of recent sensor data, with the non-volatile buffer maintaining compressed data even in power loss scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-volatile memory is used to store vehicle sensor data, then data retention during power loss is improved, but storage cost increases significantly
Solution Approach 1:
The patent segments the storage system into two distinct parts: a volatile memory buffer for high-speed uncompressed data storage and a non-volatile memory buffer for reliable compressed data storage. This segmentation allows each memory type to be used for its optimal function, reducing the need for expensive non-volatile memory while ensuring data retention during power loss.
Solution Approach 2:
The patent applies parameter changes by compressing sensor data before storing it in non-volatile memory. This compression reduces the volume of data requiring storage, thereby lowering the storage cost while maintaining data retention capabilities. The compression parameter transformation enables efficient use of non-volatile memory resources.
2Loss of information
If uncompressed sensor data is stored, then data quality and analysis capability are improved, but storage space requirements increase
Solution Approach 1:
The patent segments data storage into uncompressed and compressed portions. Uncompressed sensor data is stored in volatile memory to preserve full data quality for analysis, while compressed data is stored in non-volatile memory to reduce storage space requirements. This segmentation allows the system to maintain high data quality where needed while optimizing storage efficiency.
Solution Approach 2:
The patent applies local quality by providing different storage qualities for different data needs. High-quality uncompressed storage is provided in volatile memory for recent data requiring analysis, while compressed storage is used in non-volatile memory for historical data. This local differentiation of quality meets varying data requirements without uniformly sacrificing quality across all storage.
3Quantity of substance
If volatile memory is used for sensor data storage, then storage cost is reduced, but data loss occurs during power loss
Solution Approach 1:
The patent implements preliminary action by continuously copying data from the volatile memory buffer to the non-volatile memory buffer before power loss can occur. This proactive data replication ensures that even if power is lost, the critical sensor data has already been preserved in the non-volatile memory, preventing data loss while still allowing the use of cheaper volatile memory for primary storage.
4Reliability
If two separate buffers are implemented, then data retention reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the functionality of two separate buffers into a unified dual-buffer architecture managed by a single controller. The first buffer (volatile memory) and second buffer (non-volatile memory) are integrated into one system that automatically manages data flow between them, reducing the operational complexity despite the presence of two storage components. The controller coordinates both buffers seamlessly, presenting a simplified interface to the rest of the system.
Data Source
AI summary
An improved black box data recorder for use with autonomous driving vehicles (AVD). In one embodiment, two cyclic buffers are provided to record vehicle sensors data. A first cyclic buffer records raw vehicle sensor data on a volatile memory, while a second cyclic buffer records the same vehicle sensor data, as compressed data, on a non-volatile memory. In a case of a collision or near collision, in one embodiment the buffers are flushed into a non-volatile (NV) storage for retrieval. As long as there is no power interruption, the raw vehicle sensor data will be accessible from the NV storage. If a power interruption occurs, the raw vehicle sensor data held in the volatile memory of the first cyclic buffer will be lost and only the compressed form of the vehicle sensor data from the second cyclic buffer will survive and be accessible.