Vehicle Safety System Using Graphical Microprocessor Segmentation
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Solution Overview
Problem
Current active safety systems in vehicles face challenges in achieving the required safety integrity levels, particularly ASIL D classification, due to the cost and complexity of implementing multiple automotive grade microprocessors, and graphical microprocessors are not compliant with these standards.
Innovation Solution
The system incorporates an automotive grade microprocessor and a graphical microprocessor, with a third processor module that verifies the health and functionality of the second processor module by checking function calls, execution times, and responses, ensuring compliance with ASIL D standards by actuating critical vehicle controls such as steering, braking, and throttle only when the system is fault-free.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple automotive grade microprocessors are used to achieve ASIL D safety integrity, then the safety level is improved, but the cost and device complexity increase significantly
Solution Approach 1:
The system divides the microprocessor functionality into two separate modules: a first processor module containing an automotive grade microprocessor for safety-critical functions, and a second processor module containing a graphical microprocessor for non-critical functions. This segmentation allows the system to achieve ASIL D compliance for critical operations while using cost-effective graphical processors for other tasks, thereby reducing overall device complexity and cost while maintaining high safety integrity.
Solution Approach 2:
A third processor module acts as an intermediary or watchdog module that monitors the health and functionality of both the first and second processor modules. This intermediary module detects faults in the graphical microprocessor and prevents unsafe actuations, enabling the system to meet ASIL D requirements without requiring multiple expensive automotive grade microprocessors, thus resolving the contradiction between safety integrity and device complexity.
2Device complexity
If graphical microprocessors are used to reduce cost, then the device complexity is reduced, but the safety integrity level cannot meet ASIL D classification
Solution Approach 1:
The system segments processor responsibilities by assigning the graphical microprocessor to handle non-safety-critical functions while the automotive grade microprocessor handles safety-critical functions. This segmentation allows the use of cost-effective graphical processors without compromising ASIL D compliance for critical operations.
Solution Approach 2:
The third processor module continuously monitors the graphical microprocessor's operation and provides feedback about its health status. When faults are detected, the monitoring module sends signals to prevent unsafe actuations, ensuring that the graphical microprocessor does not compromise safety integrity while still enabling cost reduction.
3Reliability
If the third processor module monitors the second processor module to ensure fault-free operation, then the safety integrity is improved, but the device complexity increases
Solution Approach 1:
The third processor module performs self-monitoring of the system's health status by checking function calls, execution times, and responses from the graphical microprocessor. This self-service approach enables the system to detect and respond to faults without requiring additional external monitoring hardware, thereby improving safety integrity while minimizing the increase in device complexity.
Data Source
AI summary
A system of a vehicle includes an engine control module (ECM), a first processor module, sensors, a second processor module, and a third processor module. The ECM controls engine actuators based on driver inputs to a steering wheel, an accelerator pedal, a brake pedal, and a cruise control system. The first processor module includes a first microprocessor and selectively actuates at least one of an electric power steering motor, friction brakes, and a throttle valve based on processed data. The sensors sense features outside of the vehicle. The second processor module includes a second microprocessor and generates the processed data based on data from the sensors. The second microprocessor is a graphical microprocessor. The third processor module includes a third microprocessor and generates an indicator of whether a fault is present in the second processor module.