Aircraft Flight Control Piloting Law Parameterization
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Solution Overview
Problem
Modern aircraft flight control systems face challenges due to time delays and asynchronisms in the control chain, making it difficult to modify piloting laws and handle aeroservoelastic coupling, especially in flexible aircraft where structural modes align with piloting modes, leading to complex mathematical models that are hard to write explicitly.
Innovation Solution
The integration of a generic set of parameter computation modules into the flight control system that captures aerodynamic coefficients and control chain delay/filter characteristics, allowing for the generation of piloting laws that use non-filtered and non-delayed controlled variables, enabling easier computation and implementation of inputs for control surfaces across multiple axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional mathematical piloting laws are transcribed into computers using gain tables, then the piloting law can be implemented in digital form, but the method generates multiple computational steps and does not enable easy modification of the law objectives
Solution Approach 1:
The patent transforms the piloting law from a complex gain table approach into a simplified parametric form using exponential functions with adjustable parameters (α, β, γ). This allows the same mathematical structure to adapt to different piloting objectives by simply changing parameter values rather than rewriting entire gain tables, thereby reducing computational steps while maintaining implementation flexibility
Solution Approach 2:
Instead of starting with complex mathematical models and trying to implement them digitally, the patent inverts the approach by starting with a simple exponential mathematical form that naturally fits digital computation. This inverted approach simplifies the transcription process and enables easier modification of piloting objectives through parameter adjustment rather than structural changes
2Reliability
If frequency-domain filtering is applied to sensor information in flexible aircraft, then aeroservoelastic coupling between structure and piloting law is limited, but the control chain introduces time delays and asynchronisms
Solution Approach 1:
The patent applies frequency-domain filtering as a preliminary action to sensor information before it enters the piloting law computation. By pre-filtering the sensor data to remove frequencies that would cause aeroservoelastic coupling, the system prevents instability issues before they arise, while the simplified exponential piloting law structure compensates for the introduced time delays
Solution Approach 2:
The exponential piloting law with parameters (α, β, γ) acts as an intermediary that bridges the filtered sensor information and the control surface actuation. This intermediary model accounts for the time delays and asynchronisms introduced by filtering, allowing the system to maintain reliability while compensating for the time loss through the mathematical structure of the piloting law
3Loss of information
If the control chain is modeled explicitly with all delays and filters, then the complete control process can be represented, but the mathematical model becomes very complex and makes explicit writing of piloting law impossible
Solution Approach 1:
The patent extracts the essential characteristics of the control chain (delays, filters, asynchronisms) and incorporates them as parameters within the simplified exponential piloting law model. Rather than explicitly modeling every component of the control chain, the extraction approach captures the net effect of all these elements in the exponential function parameters, maintaining completeness while avoiding excessive complexity
Solution Approach 2:
The exponential piloting law with adjustable parameters (α, β, γ) serves as a universal model that can represent different control chain configurations without requiring explicit modeling of each specific delay or filter. This multi-functional model can adapt to various aircraft types and control chain architectures, maintaining complete representation capability while using a single simplified mathematical structure
Data Source
AI summary
A system including a set of computation modules configured to be utilized for computation of gains of at least one piloting law relative to at least one piloting axis of the aircraft and a data capture unit for capturing in at least one computation unit associated with a given piloting axis of the aircraft first values illustrating aerodynamic coefficients of the aircraft and second values defining delay and filter characteristics of the control chain relative to the given piloting axis, the computation unit being configured to compute the gains of the piloting law utilizing at least a part of the set of computation modules and the computation unit computing inputs intended for at least one actuator of a control surface adapted to control the aircraft relative to the given piloting axis in accordance with a corresponding current control value.