Integrated Flight Propulsion Control Research Articles

An improved high-fidelity adaptive model for integrated inlet-engine-nozzle based on mechanism-data fusion

Nowadays, there has been an increasing focus on integrated flight propulsion control and the inlet-exhaust design for the aero-propulsion system. Traditional component-level models are inadequate due to installed performance deviations and mismatches between the real engine and the model, failing to meet the accuracy requirements of supersonic conditions. This paper establishes a quasi-one-dimensional model for the inlet-exhaust system and conducts experimental calibration. Additionally, a mechanism-data fusion adaptive modeling scheme using an Extreme Learning Machine based on the Salp Swarm Algorithm (SSA-ELM) is proposed. The study reveals the inlet model's efficacy in reflecting installed performance, flow matching, and mitigating pressure distortion, while the nozzle model accurately predicts flow coefficients and thrust coefficients, and identifies various operational states. The model's output closely aligns with typical experimental parameters. By combining offline optimization and online adaptive correction, the mechanism-data fusion adaptive model substantially reduces output errors during regular flights and varying levels of degradation, and effectively handles gradual degradation within a single flight cycle. Notably, the mechanism-data fusion adaptive model holistically addresses total pressure errors within the inlet-exhaust system and normal shock location correction. This approach significantly curbs performance deviations in supersonic conditions. For example, at Ma = 2.0, the system error impressively drops from 34.17% to merely 6.54%, while errors for other flight conditions consistently stay below the 2.95% threshold. These findings underscore the clear superiority of the proposed method.

Decentralized Design for Integrated Flight/Propulsion Control of Aircraft

A direct decentralized approach to the design of integrated flight/propulsion control (IFPC) systems is considered in order to reduce complexity and validation drawbacks of centralized designs. The imposed triangular decentralized structure on the IFPC controller allows for separate evaluation of the engine controller as well as for the evaluation of the achievable performance of the overall IFPC system. Hco techniques which require the solution to Riccati-like equations are used to develop the design method. This method is applied to an aircraft aero-propulsive model and the results indicate that the approach may be a vital alternative to other techniques appearing in the literature. coordinate the functions of both the flight and propulsion systems.

Partitioning of centralized integrated flight/propulsion control design for decentralized implementation

The notion of partitioning a centralized controller into a decentralized, hierarchical structure suitable for integrated flight/propulsion control (IFPC) implementation is discussed. A systematic procedure is developed for determining partitioned airframe and engine subsystem controllers (subcontrollers), with the desired interconnection structure, that approximate the closed-loop performance and robustness characteristics of a given centralized controller. The procedure is demonstrated by application to IFPC design for a short take-off and vertical landing (STOVL) aircraft in the landing-approach-to-hover-transition flight phase. >

Robust integrated flight/propulsion control design for a STOVL aircraft using H-infinity control design techniques

Results are presented from an application of H ∞ control design methodology to a centralized integrated flight/propulsion control (IFPC) system design for a supersonic Short Take-Off and Vertical Landing (STOVL) fighter aircraft in transition flight. The emphasis is on formulating the H ∞ optimal control synthesis problem such that the critical requirements for the flight and propulsion systems are adequately reflected within the linear, centralized control problem formulation and the resulting controller provides robustness to modelling uncertainties and model parameter variations with flight condition. Experience gained from a preliminary H ∞ based IFPC design study performed earlier is used as the basis to formulate the robust H ∞ control design problem and improve upon the previous design. Detailed evaluation results are presented for a reduced order controller obtained from the improved H ∞ control design showing that the control design meets the specified nominal performance objective as well as provides stability robustness for variations in plant system dynamics with changes in aircraft trim speed within the transition flight envelope.

Development of the HIDEC Inlet Integration Mode

An integrated flight propulsion control mode called Inlet Integration has been developed and will be flight demonstrated on an F-15 test aircraft in the Highly Integrated Digital Electronic Control (HIDEC) program. The HIDEC program is conducted by the NASA Ames/Dryden Flight Research Center. The development of the Inlet Integration mode is described in this paper, including the Inlet Integration concept, the control law, its implementation on the test bed aircraft, and the predicted performance benefits. The Inlet Integration system will increase excess thrust (thrustdrag) during supersonic operation. This improvement in aircraft performance is accomplished by utilizing a calculation of engine corrected airflow from the Digital Electronic Engine Control (DEEC) to improve the scheduling of the inlet ramp positions in real time. The improvement in scheduled ramp positions will result in increased inlet performance, hence aircraft performance, while maintaining stable inlet operation. Analyses have shown the Inlet Integration system can increase excess thrust by as much as 13 percent at Mach 2.3, 40,000 ft. This thrust increase will result in increased supersonic acceleration. Inlet integration has the additional feature of improving aircraft supportability by eliminating the need for replacing inlet controllers when higher thrust derivative engines are installed in the F-15.