Hybrid Flight Control System with Mechanical Backup
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Solution Overview
Problem
Current aircraft control systems face challenges in efficiently managing increased aerodynamic loads at higher speeds and sizes, making it difficult for pilots to control aircraft effectively, and lack redundancy in case of system failures, particularly in fly-by-wire (FBW) systems which can be limited by mechanical input constraints and lack a parallel mechanical control path.
Innovation Solution
A hybrid flight control system combining FBW architectures with a mechanical control path, utilizing multiple flight control computers, servo controllers, and electro-mechanical actuators connected to aerodynamic control surfaces, along with an artificial feel system and latch-up mechanism to provide tactile feedback and ensure continued control in case of system failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a full fly-by-wire system is implemented, then control precision and system integration are improved, but system complexity and cost increase
Solution Approach 1:
The control system is divided into two independent paths: a primary fly-by-wire electronic control path and a secondary mechanical control path. Each path can operate independently, allowing the system to maintain control precision through electronic sensors and computers while reducing overall complexity by providing a simpler backup mechanism.
Solution Approach 2:
The system allows dynamic switching between electronic and mechanical control modes based on operational conditions. The mechanical path parameters (stiffness, friction) are designed to complement the electronic path, providing appropriate tactile feedback while maintaining control authority when needed.
2Reliability
If mechanical linkages are retained for redundancy, then reliability is improved, but system mass and complexity increase
Solution Approach 1:
A mechanical intermediary path is introduced that connects the control input to the control surfaces independently of the electronic fly-by-wire system. This mechanical path serves as a lightweight redundancy mechanism, providing backup control capability without requiring duplicate heavy electronic systems.
3Ease of operation
If artificial feel systems are added to FBW, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The mechanical control path inherently provides tactile feedback and artificial feel to the pilot through its physical characteristics (spring stiffness, friction elements). This eliminates the need for separate artificial feel actuators and sensors, as the mechanical path serves its own feedback function while maintaining simplicity.
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 hybrid system enhances pilot control capabilities by providing additional assistance and redundancy, reducing mass and cost compared to full FBW systems, and ensures continued safe operation by engaging mechanical linkages in case of FBW failures, improving control surface responsiveness and aircraft stability.
Implementation Method 1
an artificial feel system...configured to provide feedback to the operator(s)
Implementation Method 2
electro-mechanical actuators connected to aerodynamic control surfaces
Implementation Method 3
aerodynamic control surfaces...when moved, causes the aircraft to change attitude
Data Source
AI summary
A flight control system includes a first and second operator input means configured to receive a mechanical input from an operator and are connected to an artificial feel system and at least one sensor. The system includes a flight control computer (FCC) in data communication with the sensor, wherein the FCC receives a signal from the sensor in response to an input by the operator. The flight control system has first and second servo controllers in data communication with first and second servos, respectively, and the FCC. The servos are connected to control surfaces that, when moved, cause the aircraft to change attitude. The flight control system also includes a third and a fourth servo controller, the third and fourth servo controllers being in communication with the FCC and a dual-lane servo operably connected to a third control surface that, when moved, causes the aircraft to change attitude.