Aircraft Engine Hybrid Control with State Decoupling
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Solution Overview
Problem
Current multivariable control systems for aircraft engines, such as turboprops and turbojets, face challenges in decoupling interactions between variables like power and rotational speed, leading to unwanted torque variations and operational instability, which complicates adjustments and reduces performance.
Innovation Solution
A decentralized control system with monovariable regulators and state feedback control is implemented, using a static compensator and state feedback corrector to decouple operating parameters, allowing for simple and intuitive adjustments while maintaining system dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a decentralized control system with monovariable regulators is used, then the system structure is simple and adjustments are intuitive, but interactions between variables (power and rotational speed) are not decoupled, leading to unwanted torque variations and operational instability
Solution Approach 1:
A decoupling block is introduced as an intermediary element between the decentralized control system and the plant. This block receives control signals and generates decoupled commands that compensate for interactions between variables, thereby maintaining operational stability while preserving the simplicity of the decentralized structure.
Solution Approach 2:
The control parameters are dynamically adjusted based on operating conditions to optimize decoupling effectiveness. By changing parameters such as gain values and compensation factors according to the current state of the system, the decoupling block adapts to varying interaction levels between power and rotational speed, ensuring stable operation across different flight conditions.
2Reliability
If complex multivariable control laws are synthesized to decouple variables, then interactions between variables are reduced, but the control laws become difficult to adjust and implement
Solution Approach 1:
The control system is segmented into independent monovariable regulators that each control a single output variable, combined with a separate decoupling block. This segmentation allows each regulator to be tuned independently using simple monovariable techniques, while the decoupling block handles the interactions, thus maintaining ease of adjustment while achieving variable decoupling.
3Reliability
If state feedback control is used to decouple operating parameters, then total decoupling is achieved with simple correctors, but system dynamics may be altered
Solution Approach 1:
The state feedback corrector parameters are carefully selected and tuned to achieve decoupling while preserving the natural dynamics of the system. By adjusting feedback gains and compensation parameters based on system identification and performance specifications, the decoupling effect is achieved without significantly altering the system's response characteristics to disturbances and setpoint changes.
Data Source
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AI summary
The system for controlling a proposed aircraft engine comprises: - at least one feedback loop, - at least one state feedback control integrated in the feedback loop. The state feedback control comprises a static compensator (M) and a state corrector loop (L) which are configured so as to decouple the states formed by the operating parameters of the engine to be controlled. The monovariable controllers are then configured in such a way that the operating parameters are controlled by the commands.