Area Conversion Module Decouples Aircraft Bleed Air Control Loops
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Solution Overview
Problem
The coupling of control loops in aircraft air management systems leads to control instabilities, resulting in rapid and unnecessary changes, which accelerates the wear of control valves and imposes constraints on system design, affecting cost and performance.
Innovation Solution
An electronic controller with an area conversion module that uses multiple sensor inputs to generate calculated area set points and measurements, decoupling the sub-system control loop from the bleed air control loop by controlling the sub-system based on overall restrictiveness to flow, thereby stabilizing control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If coupled control loops are operated at different rates, then control instabilities are reduced, but system responsiveness and performance are compromised
Solution Approach 1:
The patent introduces an area conversion module as an intermediary that transforms the control signal from pressure-based to area-based control. This mediator decouples the interaction between upstream bleed control and downstream sub-system control, allowing both loops to operate at their optimal rates without causing instabilities. The area conversion module converts the effect of upstream pressure changes into equivalent area changes, enabling independent optimization of both control loops.
2Speed
If bleed control loop operates faster, then bleed pressure control is improved, but component design constraints increase and cost increases
Solution Approach 1:
The patent replaces the traditional mechanical pressure-based control mechanism with an area-based control mechanism. Instead of directly controlling pressure through mechanical means, the system uses an area conversion module that translates pressure setpoints into equivalent area setpoints, which are then used to control the sub-system valve. This substitution allows for faster control response without imposing additional mechanical design constraints on the components.
3Stability of the object's composition
If sub-system control loop is slowed down, then control instabilities are reduced, but sub-system performance and responsiveness are reduced
Solution Approach 1:
The patent changes the control parameter from pressure to area for the sub-system control loop. By using area as the control parameter instead of pressure, the sub-system can respond faster to control commands while maintaining stability. The area conversion module ensures that the transformed parameter accurately represents the physical state, allowing the sub-system to operate at higher speeds without causing control instabilities.
Data Source
AI summary
An electronic controller (16) for a sub-system (14) of an air management system (10) includes an area conversion module (40) and a sub-system area control module (34). The area conversion module includes inputs for a bleed output pressure set point (36), a bleed output pressure measurement (24), a sub-system parameter set point (38), a sub-system parameter measurement (30), and a sub-system output pressure measurement (18); and sub-modules for calculating an area set point and an area measurement. The sub-modules generate the area set point as a function of the engine bleed output pressure set point, the sub-system parameter set point, and the sub-system output pressure measurement; and the area measurement as a function of the bleed output pressure measurement, the sub-system parameter measurement, and the sub-system output pressure measurement. The sub-system area control module generates a control output for the sub-system as a function of the calculated area set point and the calculated area measurement.