• Journal of Advanced Navigation Technology
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• v.9 no.1
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• pp.34-40
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• 2005

In this paper we propose a turbojet engine controller of unmanned aircraft based on the Fuzzy-PI algorithm. To prevent any surge or a flame out event during the engine acceleration or deceleration, the PI-type fuzzy controller effectively controls the fuel flow input of the control system. The fuzzy inference rule made by the logarithm function of acceleration error improves the tracking error. Computer simulations applied to the linear model of a turbojet engine show that the proposed method has good tracking performance for the reference acceleration and deceleration commands.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.1
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• pp.1-6
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• 2014

In this paper, controller propose to prevent compressor surge and improve the transient response of the fuel flow control system of turbojet engine. Turbojet engine controller is designed by applying Artificial Neural Network PID control algorithm and make an inference by applying Levenberg-Marquartdt Error Back Propagation Algorithm. Artificial Neural Network inference results are used as the fuel flow control inputs to prevent compressor surge and flame-out for turbojet engine for UAV. High Gain Observer is used to estimate to compressor rotation speed of turbojet engine. Using MATLAB to perform computer simulations verified the performance of the proposed controller. Response characteristics pursuant to the gain were analyzed by simulation.

• Journal of Advanced Navigation Technology
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• v.3 no.2
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• pp.147-155
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• 1999

In this work variations of orbital parameters are derived from the perturbation equations under Earth oblateness and atmospheric drag. A simple and effective scheme is proposed to compute the required delta v and fuel consumption to compensate for atmospheric drag. The scheme is applied to KOMPSAT example.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.1
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• pp.1-8
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• 2009

In this paper, reorientation based on angular momentum exchange is applied for a bias momentum stabilized satellite, which is equipped with a spherical fuel tank, and the effect of liquid slosh on the attitude properties such as inertia tensor and angular rate is investigated. In order to represent the slosh motion of liquid an equivalent mechanical model is adopted and full nonlinear equations of motion for three-body system are derived. Computer simulations are performed for several cases, which use the viscosity of liquid and the center location of the tank as input parameters, mainly in order to observe how the viscosity of liquid and the center location of the tank influence the spacecraft’s attitude. The investigation includes observing time-variations of the inertia tensor, especially presence of components of product of inertia during the maneuver.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.1
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• pp.24-28
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• 2009

The reliability assessment is performed for Pressure Control Regulator of Aircraft Fuel System using reliability procedure which consists of the reliability analysis and the Failure Modes and Effects Analysis(FMEA). The target reliability as MTBF(Mean Time Between Failure) is set to 5000hr. During the reliability analysis process, the system is categorized by Work Breakdown Structure(WBS) up to level 3, and a reliability structure is defined by schematics of the system. Since the components and parts that have been collected through EPRD/NPRD. The predicted reliability to meet mission requirements and operating conditions is estimated as 4375.9hr. To accomplish the target reliability, the components and parts with high RPN have been identified and changed by analyzing the potential failure modes and effects. By changing the configuration design of components and parts with high-risk, the design is satisfied target reliability.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.13 no.3
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• pp.34-42
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• 2005

The objectives of the study are to present simple physical and mathematical models of liquid fuel in the tank of an aerospace vehicle such launch vehicle or missile and to investigate its dynamic stability for a parameter space. In this paper, liquid in the container is modeled as multi-mass system subject to parametric excitations, and a stability diagram for determination of stable-unstable regions of the motion is obtained by using an analytical method. Also, computer simulations are conducted at various parameter points to verify the analytical results, and time histories of motion are compared to explain the effect of variation of parameters of the system.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.2
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• pp.1-6
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• 2012

Four dimensional(4-D) trajectory modeling is conducted based on flight plan. The flight plan is divided into several segments which represent certain operating flight modes. Thrust, drag and fuel consumption rate of an aircraft are calculated using BADA provided by Eurocontrol. The trajectory is modeled with the rate of climb/descent calculated with Total-Energy Equation. The simulation results with a typical aircraft and its flight plan indicate that the trajectory modeled corresponds well with the suggested flight plan. The performance profiles including total endurance time and time history for speed, thrust, drag and fuel consumption were also appropriately generated.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.4
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• pp.1-7
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• 2009

The surge control system in unmanned turbojet engine must be capable of accounting uncertainties from engine transient conditions, random fluctuations of key parameters such as air pressure and fuel flow and engine modeling errors. In this paper, taking into consideration of its effectiveness as well as system stability, a fuzzy PI controller is proposed. The role of the fuzzy PI controller is to stabilize the unmanned aircraft upon occurring unexpected engine surge. The proposed control scheme is proved by computer simulation using a linear engine model. The simulation results on the state space model of a small turbojet engine illustrate the proposed control system achieves the desired performance.

• 한국항공운항학회:학술대회논문집
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• 2005.11a
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• pp.227-232
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• 2005

• 한국항공운항학회:학술대회논문집
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• 2004.11a
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• pp.211-214
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• 2004