Rotorcraft Fly-by-Wire Stabilization via Feed-Forward Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rotorcraft flight control systems face challenges in efficiently stabilizing the aircraft in response to unintended perturbations, leading to increased pilot workload and potential instability, especially in coupled flight dynamics where feedback loops are insufficient to compensate for inherent coupling of aircraft motions.
Innovation Solution
A fly-by-wire (FBW) system with a rotorcraft flight control computer (FCC) that senses unintended perturbations and engages a stabilization maneuver to transition from a first operating condition to a second condition, decoupling rotorcraft motions and reducing pilot workload through feed-forward control cross-feeds that anticipate inherent coupling of aircraft motions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback loops are used to compensate for coupled aircraft motions, then stability can be maintained, but pilot workload increases and response to perturbations becomes slower
Solution Approach 1:
The control system performs preliminary action by using feed-forward control cross-feeds to anticipate and compensate for coupled aircraft motions before they occur. The system calculates expected coupling effects based on pilot inputs and pre-applies compensating commands, eliminating the need for pilot reaction and reducing workload while maintaining stability.
Solution Approach 2:
The flight control computer acts as an intermediary between pilot inputs and aircraft controls, automatically calculating and applying compensating commands for coupled motions. This intermediary process handles the complex compensation calculations that would otherwise require pilot attention, reducing workload while maintaining reliability.
2Reliability
If feedback loops are used to compensate for coupled aircraft motions, then stability can be maintained, but the system response time increases
Solution Approach 1:
The system performs preliminary compensation for coupled motions through feed-forward control cross-feeds, calculating and applying compensating commands before the pilot even perceives the coupling effect. This eliminates the delayed response inherent in feedback loops, achieving both rapid response and stability.
Solution Approach 2:
The control system applies preliminary anti-action by pre-calculating and applying compensating commands that counteract expected coupled motions before they manifest. This proactive approach eliminates the need for reactive feedback, significantly reducing response time while maintaining stability.
3Loss of information
If manual control is used to address coupled flight characteristics, then pilot awareness is maintained, but control precision decreases
Solution Approach 1:
The flight control computer serves as an intermediary that handles precise compensation calculations for coupled motions, while the pilot maintains awareness through the control interface. The system automatically applies precise compensating commands without requiring manual adjustment, achieving both precision and pilot situational awareness.
Solution Approach 2:
The control system performs self-service by automatically calculating and applying compensating commands for coupled motions without requiring manual pilot intervention. This self-compensating mechanism maintains high precision while allowing the pilot to focus on overall flight management and maintain awareness.
Data Source
AI summary
A rotorcraft with a fly-by-wire system includes a computing device having control laws. The control laws are operable to engage a stabilization maneuver in response to a perturbation of an otherwise stable operating condition of the rotorcraft, thereby returning the rotorcraft to the stable operating condition without requiring input from the pilot. One or more control laws are further operable to increase or decrease pitch angle, roll angle, yaw rate, or collective pitch angle. In representative aspects, perturbation of the stable operating condition may occur as a result of transient meteorological conditions (e.g., wind shear, wind gust, turbulence) experienced by a rotorcraft engaged in flight operations at airspeeds between 0 knots (e.g., a hover) and about 60 knots. The control laws are further operable to permit the rotorcraft to operate with Instrument Meteorological Conditions (IMC) approval at substantially all airspeeds within a normal flight envelope of the rotorcraft.