Redundant Flight Control Bus Architecture for Fault Tolerance
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Solution Overview
Problem
Conventional flight control systems for aircraft lack sufficient resilience against technical failures, particularly due to weight and cost issues associated with traditional triplex architectures and bus communication technologies, which are slow, costly, and limited in configuration.
Innovation Solution
A redundant flight control system with multiple independent bus sub-systems and communication protocols, where each bus node communicates via two different sub-systems using distinct protocols, and each sub-system comprises multiple independent communication buses, ensuring high redundancy and fault tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional triplex architecture with three independent flight control computers and three independent networks is used, then reliability is improved, but weight increases due to higher number of busses, connectors and necessary physical path segregation
Solution Approach 1:
The network is segmented into multiple independent communication busses (first bus, second bus, third bus) that are logically separated but physically integrated through a single network controller. This segmentation provides fault isolation while avoiding the weight penalty of complete physical segregation of all network paths.
Solution Approach 2:
Multiple communication busses are merged into a single network controller that handles routing and protocol management centrally. This consolidation reduces the number of physical connectors and wiring harnesses while maintaining the functional independence of each bus through software-based virtualization and protocol handling.
2Reliability
If conventional bus communication technologies (ARINC-429, MIL-STD-1553, AFDX) are used, then reliability is improved, but cost increases due to proprietary single supplier monopoly and high implementation costs
Solution Approach 1:
The network controller is designed with multi-functionality to support multiple communication protocols (ARINC-429, MIL-STD-1553, AFDX, CAN bus) within a single device. This universal approach eliminates the need for separate dedicated hardware for each protocol, reducing costs while maintaining compatibility with various aviation standards through software configuration.
Solution Approach 2:
The system allows dynamic changing of communication parameters and protocols based on operational requirements. The network controller can switch between different bus protocols and configure communication settings adaptively, providing the reliability of standardized protocols without being locked into proprietary implementations, thereby reducing supplier dependency and cost.
3Reliability
If conventional bus communication technologies are used, then reliability is improved, but device complexity increases due to need for critical bus controller or router and complex technology (TTE, TTP)
Solution Approach 1:
The functions of multiple critical bus controllers and routers are merged into a single network controller that manages all communication busses. This consolidation reduces the number of complex routing decisions and critical failure points while maintaining protocol compliance through integrated software management of message routing, prioritization, and error handling.
Solution Approach 2:
The network controller acts as an intermediary that simplifies communication between flight control computers and other aircraft systems. It handles protocol conversion, message routing, and error management, thereby reducing the complexity burden on individual flight control computers and providing a unified interface for all bus communications.
4Reliability
If conventional bus communication technologies are used, then reliability is improved, but weight increases due to many wires (e.g., RS-422 full duplex)
Solution Approach 1:
Multiple full-duplex communication channels are merged into a single network infrastructure that shares physical wiring resources. The network controller multiplexes multiple logical communication streams over shared physical busses, dramatically reducing the total wire count and connector quantity while maintaining full-duplex communication capabilities through time-division or protocol-based multiplexing.
Solution Approach 2:
The system transitions from a one-to-one physical wiring model to a many-to-many virtualized communication model. By introducing a network layer that operates in the logical dimension, multiple communication paths can be established over shared physical infrastructure, reducing wiring complexity and weight while maintaining the functional independence and reliability of separate communication channels.
Data Source
AI summary
A flight control system for an aircraft comprises a flight control computer system connected via a bus system with a plurality of bus nodes, which each are configured to at least one of controlling an associated aircraft device based on command messages received from the flight control computer system via the bus system and sending information messages to the flight control computer system via the bus system. The bus system is a redundant bus system comprising plural independent bus sub-systems, wherein each bus node is configured to communicate with the flight control computer system via two different bus sub-systems, wherein each bus node further is configured to communicate with the flight control computer system on basis of an associated predetermined bus communication protocol via a first bus sub-system and on basis of an associated predetermined bus communication protocol via a second bus sub-system.