Rotorcraft Fly-By-Wire Control with Flight Director Decoupling
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Solution Overview
Problem
As rotorcraft become larger and more complex, the differences between flying rotorcraft and fixed-wing aircraft become more pronounced, with tightly coupled flight parameters and controls, making it challenging to maintain stable flight and reduce pilot workload, especially in varying speed regimes.
Innovation Solution
A fly-by-wire (FBW) control system with a flight control computer (FCC) and a flight director system that decouples flight characteristics, allowing the FCC to generate control signals based on target error signals from the flight director system, enabling automated flight control and reducing pilot workload by adjusting power and control inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a rotorcraft becomes larger and more complex, then the aerodynamic lift and thrust generation capability is improved, but the flight stability and control difficulty worsens due to tightly coupled flight parameters
Solution Approach 1:
The patent introduces a flight director system as an intermediary between the pilot and the fly-by-wire control system. This flight director computes desired flight characteristics and generates target error signals that mediate the control process, helping to decouple the tightly coupled flight parameters and reduce pilot workload while maintaining control of the larger, more complex rotorcraft
2Extent of automation
If a fly-by-wire control system is implemented, then automated flight control and reduced pilot workload are achieved, but the system complexity increases
Solution Approach 1:
The patent segments the control system into distinct functional components: the flight director system that computes desired flight characteristics and generates target error signals, and the fly-by-wire control system that executes control based on these signals. This segmentation allows automated flight control while organizing system complexity into manageable, modular components with clear interfaces
3Adaptability or versatility
If flight parameters are tightly coupled, then the rotorcraft can operate in varying speed regimes, but the pilot workload increases and stable flight becomes challenging
Solution Approach 1:
The flight director acts as an intermediary that computes desired flight characteristics and generates target error signals, effectively decoupling the tightly coupled flight parameters from the pilot's direct control. This allows the rotorcraft to operate in varying speed regimes while the flight director manages the complexity, significantly reducing pilot workload
Solution Approach 2:
The system implements feedback through target error signals that represent the difference between desired and actual flight characteristics. The fly-by-wire control system uses these error signals to continuously adjust control inputs, maintaining stable flight across varying speed regimes while reducing the cognitive burden on the pilot
Data Source
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AI summary
A rotorcraft (101) including a fly-by-wire control system (201) also includes a flight control computer (FCC, 205) operable to control flight of the rotorcraft (101) by sending control signals to flight control elements of the rotorcraft (101). The rotorcraft includes a flight director system (250) coupled to the FCC (205) and configured to send a target signal to the FCC (205). The target signal indicates a desired flight characteristic of the rotorcraft (101). The FCC (205) is configured to receive the target signal from the flight director system (250), determine control signals based on the target signal, and send the control signals to the flight control elements (107, 121) of the rotorcraft to control the flight of the rotorcraft (101) based on the target signal.