Autonomous Vehicle Data Recorder With Dual Cyclic Buffers
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Solution Overview
Problem
Autonomous vehicles face challenges in preserving sensor data during accidents due to power loss, which can result in data loss and limited endurance of non-volatile memory, affecting accident analysis and ADAS improvements.
Innovation Solution
A data recorder with separate cyclic buffers for accident and training sensor data, utilizing high-endurance non-volatile memory like cross-point memory and a backup power source to ensure data preservation and continuous operation during accidents, and efficient data transfer to a remote server for analysis and system updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If volatile memory is used to store sensor data, then data can be accessed quickly during operation, but data is lost when power is lost during an accident
Solution Approach 1:
The system performs preliminary action by continuously copying sensor data from volatile memory to non-volatile memory before power loss occurs. The data recorder is configured to transfer data in advance, ensuring that even if power is lost during an accident, the sensor data is already preserved in non-volatile memory and can be retrieved for analysis.
2Reliability
If non-volatile memory is used to store sensor data, then data is preserved during power loss, but the memory has limited endurance due to programming and erasing cycles
Solution Approach 1:
The system segments the storage function by using two types of memory: volatile memory for active data buffering and non-volatile memory for persistent data storage. This segmentation allows the system to leverage the speed of volatile memory while using non-volatile memory only when needed for data preservation, thereby extending the overall system reliability without过度 stressing the non-volatile memory's endurance.
Solution Approach 2:
The system implements a cyclic buffer approach where sensor data is continuously overwritten in volatile memory. When data needs to be preserved, it is copied to non-volatile memory and then the volatile memory space is recovered for new data. This allows the system to maintain a rolling window of sensor data while minimizing the number of write operations to non-volatile memory, thus preserving its endurance.
3Reliability
If separate cyclic buffers are used for accident and training data, then data integrity is maintained, but device complexity increases
Solution Approach 1:
The system segments the data buffer into two separate cyclic buffers: one for accident data and one for training data. This segmentation ensures that accident data and training data are stored independently, preventing mixing or corruption between the two data types. The separate buffers simplify data retrieval and management by allowing independent access to each data type without interfering with the other.
Data Source
AI summary
Systems, methods and apparatus to collect sensor data generated in an autonomous vehicle. Sensors of the vehicle generate a sensor data stream that is buffered, in parallel and in a cyclic way, in a first cyclic buffer and a larger second cyclic buffer respectively. An advanced driver assistance system of the vehicle generates an accident signal when detecting or predicting an accident and provides a training signal when detecting a fault in object detection, recognition, identification or classification. The accident signal causes a sensor data stream segment to be copied from the first cyclic buffer into a slot of a non-volatile memory, selected from a plurality of slots in a round robin way. The training signal causes a sensor data stream segment to be copied from the second cyclic buffer into an area of the non-volatile memory outside of the slots reserved for the first cyclic buffer.