Aircraft Flight Control Law Blending Across Mode Transitions
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Solution Overview
Problem
Existing aircraft control methods face challenges in managing conflicts between different actuators during mode transitions, leading to 'fight of control' issues and inefficient regulation of multiple control modes, particularly when transitioning between vertical and cruise flight modes.
Innovation Solution
A method that dynamically adjusts the maximum and minimum limit values of control volumes defined by parameter ranges for each control law, allowing for smooth and continuous blending between control laws to manage multiple configurations or modes, ensuring continuous and stable aircraft behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple control laws are used for different flight modes, then the aircraft can operate in multiple configurations (copter mode and jet mode), but control conflicts arise during mode transitions causing instability and discomfort
Solution Approach 1:
The patent implements dynamic adjustment of control volume limits during mode transitions. The maximum and minimum limit values of control volumes are not fixed but are dynamically modified based on the current flight condition and transition state, allowing the control system to adaptively blend between copter mode and jet mode control laws without causing instability or control conflicts
Solution Approach 2:
The patent changes the parameter ranges of control parameters by dynamically adjusting the maximum and minimum limit values of control volumes. This parameter modification allows different control laws to coexist and blend smoothly during transitions, resolving the contradiction between multi-mode adaptability and control stability
2Ease of operation
If control volumes with fixed parameter ranges are used, then the control system is simple to implement, but the transition between control modes is discontinuous causing discomfort and potential safety issues
Solution Approach 1:
The control volumes are made dynamic rather than static. The maximum and minimum limit values are continuously adjusted based on flight conditions, enabling smooth and continuous transitions between control modes while maintaining acceptable system complexity through a structured adjustment mechanism
3Reliability
If discrete switching between control modes is used, then the control system is simple and fast, but discontinuous behavior occurs causing discomfort and safety concerns
Solution Approach 1:
The patent ensures continuity of control action during mode transitions by dynamically adjusting control volume limits. Both control modes remain active during transition with their respective control laws continuously computed, and the blending is achieved through gradual modification of control parameter ranges rather than abrupt switching, eliminating discontinuous behavior while maintaining safety
Data Source
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AI summary
We propose a method of controlling an aircraft having multiple configurations or modes, wherein each configuration is controlled by a different control law implemented by a flight control device and transition from one configuration to another configuration is achieved by gradually blending out a control law for said one configuration and by gradually increasing an impact of a control law for said other configuration in said flight control device based on an estimated flight condition of the aircraft by dynamically adjusting, in said flight control device, respective maximum and minimum limit values of control volumes, which control volumes are defined by parameter ranges of control parameters in connection with a corresponding control law for said one configuration and for said other configuration, respectively.