Distributed Flight Control System Bus Architecture
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Solution Overview
Problem
Modern flight control systems in aircraft require a large number of cables for communication between the computer and actuators/control surfaces, leading to installation complexity, increased weight, and sensitivity to electromagnetic disturbances, particularly in composite material aircraft.
Innovation Solution
A distributed flight control system utilizing a multiplexed communications bus with remote terminals that transmit and receive command messages and state information, reducing the need for extensive cabling and electromagnetic shielding, and employing a differentially-powered twisted pair bus with a master-slave protocol for robust communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional analog cable-based control systems are used, then reliable control signal transmission is achieved, but the number of cables increases significantly leading to increased weight and installation complexity
Solution Approach 1:
The patent combines multiple separate control and monitoring cables into a single digital data bus that carries all communication between the flight control computer and actuators. This merging of multiple communication channels into one integrated digital system reduces cabling complexity while maintaining reliable control signal transmission through digital protocols and error checking mechanisms.
Solution Approach 2:
The patent replaces the mechanical analog cable system with a digital electronic communication system. Instead of using multiple analog voltage signals transmitted over separate cables, the system uses digital data packets transmitted over a single bus, substituting mechanical signal transmission with electronic digital communication to reduce physical cable requirements.
2Object-affected harmful factors
If extensive cabling and shielding are used to protect against electromagnetic disturbances, then electromagnetic protection is improved, but the weight of the aircraft increases
Solution Approach 1:
The patent replaces the physical shielding mechanism with digital immunity. Instead of relying on thick metallic shielding to block electromagnetic interference, the system uses digital signal transmission with error detection and correction capabilities, making the control system immune to electromagnetic disturbances without adding significant weight.
Solution Approach 2:
The patent changes the signal transmission parameter from analog voltage levels to digital binary codes. This parameter change fundamentally alters how the system handles electromagnetic interference, as digital signals can be regenerated and error-checked, making them inherently more resistant to electromagnetic disturbances compared to analog signals that require heavy shielding.
3Reliability
If the computer is overdimensioned to handle increased I/O requirements and electrical protection, then system robustness is improved, but the size of the avionics bay increases
Solution Approach 1:
The patent segments the flight control system into modular components: the flight control computer, the data bus, and intelligent actuator units. Each actuator contains its own control logic and monitoring capabilities, distributing the computational burden and reducing the requirements for the central computer. This segmentation allows for a more compact overall system design while maintaining robustness through distributed intelligence.
4Reliability
If analog control cables are used in composite material aircraft, then control signal transmission is maintained, but sensitivity to lightning and electromagnetic disturbances increases
Solution Approach 1:
The patent changes the signal transmission parameter from analog to digital, which fundamentally alters the system's response to electromagnetic disturbances. Digital signals can be detected, verified, and corrected through protocol-level error checking, making the system immune to the type of interference that plagues analog systems in composite aircraft. This parameter change eliminates the need for extensive shielding while maintaining reliable control signal transmission.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces cabling complexity, weight, and electromagnetic sensitivity, providing a robust flight control system that is less prone to disturbances and easier to route through confined aircraft spaces.
Implementation Method 1
at least one communications bus; at least one computer situated in the avionics bay of the aircraft, and adapted to calculate flight commands and to transmit them over said bus in the form of command messages
Implementation Method 2
employing a differentially-powered twisted pair bus with a master-slave protocol for robust communication
Data Source
AI summary
A flight control system for an aircraft, controlling a plurality of actuators adapted to actuate control surfaces of the aircraft, including: at least one communications bus; at least one computer situated in the avionics bay of the aircraft, and adapted to calculate flight commands and to transmit them over the bus in the form of command messages; and at least a first remote terminal connected to the bus, adapted to control a control surface actuator, and to acquire the state of the actuator from information provided by at least a first sensor, the first terminal receiving command messages from the computer and transmitting electrical orders to the actuator as a function of the command messages received in this way, and also transmitting messages to the computer, at its request, relating to the state of the actuator as a function of the information provided by the first sensor.