Aircraft Flight Control Across the Full Envelope With Sliding Mode
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Solution Overview
Problem
Existing aircraft control systems are complex and costly to tune, particularly when dealing with nonlinear dynamics, and often rely on linearization, which is not tailored to the aircraft's full operating envelope.
Innovation Solution
A method combining sliding mode control and feedback linearization techniques to control bank angle, heading angle, and altitude by computing target rates of change and body roll rates using error thresholds and sigmoid functions, allowing for adaptive control across the entire flight envelope.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If linearization about a nominal operating point is used, then the control system is simpler to design, but it is not tailored to the aircraft's nonlinear dynamics and cannot achieve desired performance across the entire operating envelope
Solution Approach 1:
The patent applies dynamic control techniques (sliding mode control and feedback linearization) that adapt to changing flight conditions in real-time, rather than using static linearization about a single operating point. This allows the controller to handle the aircraft's nonlinear dynamics across the entire operating envelope while maintaining reasonable design complexity through systematic methodologies.
2Adaptability or versatility
If tunable parameters are scheduled according to aircraft orientation and flight conditions, then desired performance across the entire operating envelope can be achieved, but the task becomes complex and costly
Solution Approach 1:
The patent systematically changes control parameters through sliding mode control and feedback linearization techniques that automatically adapt to different flight conditions. Rather than manually scheduling parameters across multiple operating points, the controller dynamically adjusts parameters based on real-time aircraft state, reducing both complexity and cost while maintaining performance across the operating envelope.
3Speed
If aggressive maneuvers are executed, then mission objectives can be achieved, but control precision and smoothness may be compromised
Solution Approach 1:
The sliding mode control technique employs periodic switching actions to achieve rapid maneuver execution while maintaining precision. The controller alternates between control states to drive the system toward the desired trajectory, ensuring both aggressive maneuver capability and control precision through systematic periodic adjustment of control inputs.
Solution Approach 2:
The feedback linearization component continuously monitors aircraft state and adjusts control inputs to maintain precision during aggressive maneuvers. By incorporating real-time feedback about aircraft orientation, rate of change, and deviation from desired path, the system can execute fast maneuvers while compensating for nonlinear effects to preserve control precision and smoothness.
Data Source
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AI summary
Methods and systems for controlling a bank angle, a heading angle and an altitude of an aircraft during flight are provided. The methods and systems disclosed herein make use of sliding mode control and feedback linearization control (nonlinear dynamic control) techniques. The methods and systems can provide autopilot-type functions that can autonomously execute aggressive maneuvers as well as more gentle maneuvers for aircraft.