Fly-By-Wire Bus Layout for Fault-Tolerant Redundancy
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Solution Overview
Problem
Modern aircraft fly-by-wire systems require redundancy to ensure fault tolerance, leading to increased wiring and complexity, which raises costs and complexity, while maintaining data integrity and safety.
Innovation Solution
A fly-by-wire system utilizing a bus arrangement with unique subsets of CAN buses connecting distinct flight control and actuation modules, providing independent communication paths and redundancy without triplicate connections, and using CRCs for data integrity, thereby reducing wiring and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundancy is implemented in fly-by-wire systems to ensure fault tolerance, then reliability is improved, but device complexity and wiring quantity increase
Solution Approach 1:
The system segments the communication network into multiple independent CAN buses (CAN1, CAN2, CAN3), with each bus carrying a subset of communication channels. This segmentation allows redundancy to be achieved by distributing communication paths across separate physical buses, so that a fault in one bus does not affect all communication channels. Each actuator control module is connected to different subsets of these segmented buses, creating independent communication paths that reduce overall wiring complexity while maintaining fault tolerance.
Solution Approach 2:
The patent transitions from traditional point-to-point or fully redundant wiring architectures to a multi-dimensional CAN bus network topology. By organizing communication channels across multiple dimensional layers (different CAN buses with unique subset assignments), the system achieves redundancy without requiring triplicate connections for every signal. This dimensional reorganization allows the same level of fault tolerance with reduced wiring quantity and complexity.
2Reliability
If redundant wiring is added to ensure data integrity, then reliability is improved, but cost and wiring quantity increase
Solution Approach 1:
Communication channels are segmented and distributed across multiple CAN buses rather than using fully redundant parallel wiring for each channel. Each actuator control module receives data through unique subset assignments from the available CAN buses, creating multiple independent paths for data transmission. This segmentation achieves data integrity through path diversity without requiring complete triplicate wiring for every signal, thereby reducing total wiring quantity.
Solution Approach 2:
The CAN bus network provides universal communication infrastructure that serves multiple functions simultaneously. The same set of CAN buses (CAN1, CAN2, CAN3) is used by multiple flight control modules and actuator control modules for different communication channels. This multi-functional use of the bus system achieves redundancy and data integrity without requiring separate dedicated redundant wiring for each communication channel, reducing overall wiring quantity and cost.
Data Source
AI summary
Aircraft fly-by-wire systems and related vehicle electrical systems are provided. In one embodiment, an electrical system suitable for use with a control surface of a vehicle, such as an aircraft, is provided. The electrical system includes a plurality of communications buses and a plurality of control modules, wherein each of the plurality of control modules is connected to a respective subset of the plurality of communications buses that is unique among the plurality of control modules, and a plurality of actuation control modules associated with the control surface, wherein each of the plurality of actuation control modules is connected to a respective subset of the plurality of communications buses that is unique among the plurality of actuation control modules. Thus, each of the control modules is isolated from at least one of the communications buses.