Flight Control System Processor Restart via RAM Sector Switching
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Solution Overview
Problem
Current flight control systems face interruptions and prolonged recovery times due to software errors or faults, which can disrupt the continuous operation of aircraft or vehicle control systems, especially in critical situations like radiation events.
Innovation Solution
The method involves copying an executable program from ROM to both low-RAM and high-RAM during startup and rapidly transferring it between these memory sectors to facilitate a quick restart of the processor, reducing the need for a full restart and minimizing interruption time in the control loop, utilizing a direct memory access engine to offload data transfer tasks from the processor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the processor is restarted after a software error, then the system can recover from the fault, but the control loop operation is interrupted for a prolonged period
Solution Approach 1:
The patent segments the memory into multiple sectors (first sector, second sector, third sector) with different functions: one for storing the executable program, another for storing a restored image, and a third for temporary transfer operations. This segmentation enables rapid switching between memory sectors during processor restart, reducing the time the control loop remains interrupted while maintaining reliable system recovery capability.
2Reliability
If a full processor restart is performed, then the system resets to a known good state, but the restart process is time-consuming and disrupts continuous operation
Solution Approach 1:
The patent performs preliminary actions by maintaining a restored image of the executable program in a second memory sector before any error occurs. When a software error is detected, the system can immediately switch to this pre-prepared restored image without needing to perform time-consuming operations during the restart process. This preliminary preparation enables rapid recovery while ensuring the system resets to a known good state, thereby maintaining continuous operation efficiency.
Solution Approach 2:
The patent creates and maintains copies of the executable program in different memory sectors. A first copy is stored in a first sector, and a restored image copy is maintained in a second sector. During normal operation, the processor executes from the first sector. When an error occurs, the system switches to execute from the second sector's restored copy. This copying mechanism enables rapid restart without full reinitialization, reducing interruption time while ensuring reliable recovery to a known good state.
3Reliability
If the processor executes from ROM, then the program is stable and protected, but transfer and restarting operations are slower compared to RAM execution
Solution Approach 1:
The patent uses RAM memory sectors as intermediary storage between the stable ROM and the processor. The executable program is loaded from stable ROM into a first RAM sector for execution. When errors occur, the system can rapidly switch between RAM sectors without repeatedly accessing ROM, thereby maintaining program stability through controlled loading while achieving faster execution and restart speeds through RAM's rapid access characteristics. The DMA engine further mediates these transfers, enabling high-speed operations.
Solution Approach 2:
The patent replaces slow mechanical/physical ROM access with electronic RAM access for processor execution. By loading the program from ROM into RAM and executing from RAM, the system achieves significantly faster access speeds while maintaining stability through the controlled loading process and error detection mechanisms. The use of DMA (Direct Memory Access) further substitutes processor-mediated memory management with a dedicated hardware mechanism, reducing overhead and improving execution speed.
4Device complexity
If the system uses a single memory sector for the executable program, then the memory structure is simple, but restart operations require time-consuming data transfer from ROM
Solution Approach 1:
The patent segments the memory structure into multiple sectors (first sector for executable program, second sector for restored image, third sector for temporary transfer) rather than using a single memory sector. This segmentation enables the system to perform rapid restart operations by switching between sectors without requiring time-consuming data transfers from ROM. The multi-sector structure maintains relative simplicity while dramatically reducing restart time through parallel preparation of restored images and rapid sector switching.
Data Source
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AI summary
A flight control system (100) is provided. The flight control system includes at least one sensor (112) configured to collect data, a flight controller (110) coupled to the at least one sensor. The flight controller (110) includes a random access memory (RAM) device (144) configured to store at least one executable program in a first RAM sector and a second RAM sector of the RAM device, and a processor (140) configured to execute the at least one executable program from the first RAM sector to process the sensor data, and to output operational instructions, and at least one actuator (116) coupled to the flight controller, the actuator configured to receive and execute the operational instructions.