Control Allocation via Virtual Effectors for Nonlinear Aircraft Dynamics
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Solution Overview
Problem
Legacy flight control systems struggle to allocate control authority among control effectors in aircraft due to nonlinear and non-monotonic interactions, which are not adequately addressed by existing methods that assume linearity or use iterative techniques, making them unsuitable for real-time embedded software applications.
Innovation Solution
A control allocation method using a multi-input-multi-output function g(x,u) to predict vehicle linear and angular accelerations, modifying control commands to account for nonlinear effects, and introducing virtual control effectors to ensure monotonic responses, employing dynamic inversion control laws and time-scale separation principles to manage redundant control effectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If iterative techniques such as linear programming are used to account for nonlinear and non-monotonic control effector interactions, then control accuracy is improved, but computational complexity and processing time increase making them unsuitable for embedded software applications
Solution Approach 1:
The patent transforms the control allocation problem by changing the parameter representation from direct control effector commands to virtual control effector commands. This parameter transformation enables the use of a pseudo-inverse algorithm that can handle nonlinear and non-monotonic relationships without requiring iterative solutions, thus maintaining computational efficiency while improving control accuracy.
Solution Approach 2:
The patent introduces virtual control effectors as an intermediary layer between the reference commands and the actual control effectors. This intermediary transformation allows the system to account for nonlinear interactions and aerodynamic effects without requiring complex iterative algorithms, resolving the contradiction between accuracy and computational complexity.
2Ease of manufacture
If traditional pseudo-inverse methods are used for control allocation, then computational simplicity is maintained, but nonlinear and non-monotonic effects of control effectors are not adequately accounted for
Solution Approach 1:
The patent applies parameter changes by transforming the control allocation equations to work with virtual control effectors and their associated commands. This transformation allows the simple pseudo-inverse algorithm to inherently account for nonlinear and non-monotonic effects that traditional methods miss, thereby maintaining computational simplicity while improving control accuracy.
3Productivity
If control allocation algorithms assume linearity of control effector effects, then computational efficiency is improved, but the algorithms fail to account for significant interactions between control effectors
Solution Approach 1:
The patent introduces virtual control effectors as an intermediary that captures the nonlinear interactions between actual control effectors. This allows the control allocation algorithm to maintain computational efficiency through a single pseudo-inverse calculation while reliably accounting for complex effector interactions through the virtual effector transformation.
Data Source
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AI summary
Method and apparatus is disclosed which allocates the execution of a commanded vehicle maneuver among the vehicle's control effectors capable of affecting such maneuver, with consideration given to the possible nonlinear and/or non-monotonic effects each control effector's displacement may have on the vehicle and on each other's performance.