Aircraft Flight Control Computers for Continuous Autopilot Availability
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Solution Overview
Problem
Current flight control systems for aircraft lack the availability of automatic pilot mode due to the complexity of automatic pilot laws, which limits their operational reliability, especially in autonomous aircraft and drones, where the probability of loss of availability needs to be extremely low without increasing the number of computers or complicating the system.
Innovation Solution
Configuring all main computers to implement autopilot laws with distinct tolerance levels, allowing for permanent availability of autopilot mode by isolating autopilot and actuator control functions into separate software partitions, and using dissimilar hardware types to reduce failure risks and improve operational availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If automatic pilot laws are implemented in all main computers, then availability of automatic pilot mode is improved, but device complexity increases due to the complexity of automatic pilot laws
Solution Approach 1:
The patent divides the computer system into multiple main computers (at least two) that operate in parallel, with each computer capable of implementing automatic pilot laws independently. This segmentation allows the system to maintain automatic pilot availability even if one computer fails, while distributing the computational complexity across multiple units rather than concentrating it in a single complex system.
Solution Approach 2:
The patent introduces a tolerance parameter that can be adjusted based on operational conditions. When automatic pilot laws are executed, a tolerance level is applied to compare results from different computers or iterations, allowing the system to accept solutions within a defined range rather than requiring exact precision. This parameter change enables the system to handle the complexity of automatic pilot laws while maintaining reliability.
2Manufacturing precision
If main computers control actuators with high precision, then manufacturing precision of control is improved, but reliability decreases due to stricter tolerance levels increasing failure risk
Solution Approach 1:
The patent implements a dynamic tolerance mechanism where the tolerance level for actuator control is not fixed but can be adjusted based on operational context. The system can switch between high-precision mode (with stricter tolerance) when conditions permit and more robust mode (with relaxed tolerance) when reliability is prioritized. This dynamic adjustment allows the system to optimize between precision and reliability in real-time.
Solution Approach 2:
The patent prepares for potential failures by implementing a cushioning mechanism through the tolerance parameter. By allowing control within a tolerance range rather than requiring exact precision, the system creates a buffer that protects against failures due to minor deviations or computational errors. This beforehand cushioning ensures that small errors do not propagate into system failures, maintaining reliability even when operating at high precision.
Data Source
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AI summary
The flight control system (20) of an aircraft comprises a set (18) of aircraft control actuators, and a set of flight control computers consisting solely of a set of duplex primary computers (10a, 10b, 10c, 10d) and at least one backup computer (17). All primary computers are configured to implement aircraft autopilot laws. The set of primary computers includes two computers (10a, 10b) of a first hardware type, configured to control actuators of the actuator set according to a first tolerance level, and two computers (10c, 10d) of a second hardware type, dissimilar to the first hardware type, configured to control actuators of the actuator set according to a second tolerance level, less stringent than the first tolerance level.