Air/Ground Logic Management for Actuator Wind-Up Prevention
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Solution Overview
Problem
Conventional aircraft control systems, particularly fly-by-wire (FBW) systems, face challenges in managing air/ground transitions effectively, leading to difficulties in controlling rotorcraft during landing and takeoff, which can result in accidents and safety concerns due to inadequate logic design for actuator wind-up and loss of pilot feedback.
Innovation Solution
An air/ground contact logic management system that regulates control authority by using a combination of Weight-on-Gear sensors and radar altimeter data to classify flight modes and manage actuator integrators, preventing actuator wind-up and ensuring safe transitions between in-flight and on-ground modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If FBW systems place the cyclic controller close to the center position regardless of ground slope or sideward wind conditions, then the aircraft's maneuverability and stability are improved, but the pilot's feedback feel is removed and handling difficulty increases
Solution Approach 1:
The control system dynamically adjusts the cyclic controller position based on detected ground conditions (slope angle, wind direction). The system transitions from a static center-positioned controller to a dynamic positioning system that adapts to environmental conditions, resolving the contradiction between automated stability control and pilot handling feedback
Solution Approach 2:
The system implements feedback by providing the pilot with tactile or visual information about ground conditions and aircraft state. This allows the pilot to maintain situational awareness and make informed control decisions while the FBW system manages stability, addressing the loss of pilot feedback feel
2Manufacturing precision
If FBW systems use automated control logic during air/ground transitions, then control precision is improved, but actuator wind-up occurs and control authority is lost
Solution Approach 1:
The system performs preliminary actions by detecting air/ground transition conditions in advance and pre-adjusting control law parameters and actuator positions before the transition is complete. This prevents actuator wind-up by preparing the system proactively, maintaining both control precision and reliability during critical transition phases
Solution Approach 2:
The control system dynamically switches between different control laws and authority levels based on the detected flight phase (in-flight, transition, on-ground). This dynamic adaptation prevents actuator saturation while maintaining precise control, resolving the contradiction between automated control precision and system reliability
3Device complexity
If conventional aircraft control systems are used during landing, then system simplicity is maintained, but inadequate logic design leads to actuator wind-up and safety concerns
Solution Approach 1:
The system introduces an intermediary logic layer that sits between the pilot inputs and the actuator commands. This intermediary layer manages the complex transition logic and actuator coordination, preventing wind-up while maintaining a relatively simple interface for the pilot and preserving landing safety without requiring complete system redesign
Data Source
AI summary
An air/ground contact logic management system for use with fly-by-wire control systems in an aircraft. The system includes a first sensor configured to provide an output signal to determine when the aircraft is in a transition region. A logic management system is in communication with the first sensor and is configured to receive and process the output signal and classify a mode of the aircraft. A controller receives signal data from the logic management system and communicates with a control axis actuator to regulate a level of control authority provided to a pilot. The control authority is individually regulated within each integrator as a result of the individual landing gear states.