• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1613-1616
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• 2010

본 논문은 실시간 운영체제인 Xenomai 를 사용하여, 회전익 무인항공기 소프트웨어 개발에 대한 내용을 설명하고 있다. 실시간 운영체제 사용하여 고정 순위 우선 스케줄링을 채택함으로써 데드라인의 타이밍(Timming) 결정성을 보장하였고, 이기종 시스템과의 호환성과 확장성을 고려하여 POSIX API 를 사용하여 멀티 쓰레드를 구현하였다. 또한 실시간 드라이버 모델(RTDM : Real-Time Driver Model)을 사용하여 획득한 데이터를 실시간 전송이 가능하도록 하였다. 본 논문은 실시간 운영체제를 무인항공기에 적용하고 구현된 비행제어 컴퓨터와 제어 소프트웨어를 비율 단조 스케줄링을 적용하여 무인항공기의 쓰레드들의 응답 속도 및 안정성을 보장하는 방안을 제시하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.4
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• pp.363-372
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• 2016

SIGMA(Scientific cubesat with Instruments for Global Magnetic field and rAdiation) CubeSat has been developed for magnetic field measurement of the Earth and space radiation measurement at Kyung Hee university. The flight software plays important roles in controlling the satellite and processing the data in the space mission. In this paper, the Flight Software has been implemented to process all the tasks in the one thread without RTOS(Real Time Operating System). This is an effective mothed not only to concentrate the space mission of CubeSat but also to reduce the overhead of the Flight Software by considering the mission perform procedures and the system control methods.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.926-931
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• 2003

본 연구는 비압축성 유동에 노출되어 있는 2-D wing-flap 시스템의 공탄성 응답의 능동제어를 다루고 있다. 본 연구 논문의 목표는 LQG 제어법칙을 수행함으로써 임계 비행속도하에서 플러터의 비안정성을 억제하고 돌풍이나 blast load에 의한 임계 공탄성 응답의 성능을 향상시키는 것과 동적응답을 감쇠하는 수행능력들을 증명하는데 있다.

• Journal of the Korea Society for Simulation
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• v.15 no.1
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• pp.43-50
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• 2006

The major objective of this paper is to propose a hybrid simulation environment for autonomous UAV system by integrating the continuous-time model with discrete-event model. Proposed system is able to support high autonomous behavior by combining the planner, recognizer, and controller model to deal with the HL20 AIRPLANE model. Thus, the high level decision may be efficiently issued even upon the unexpected circumstance. The proposed system model has been successfully verified by several simulation test performed on the DEVS simulation S/W environment.

• Aerospace Engineering and Technology
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• v.2 no.1
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• pp.124-132
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• 2003

The function and performance test of the developed sub-system should be conducted before integrating into the total system. For the successful achievement of the flight test, the integration tests of sub-systems must be performed to eliminate and prevent abnormal conditions, which may happen due to ground problems, Electro-Magnetic Interference noises, and so on. This paper describes the certification test procedure and results for the roll axis attitude control system of Korea Sounding Rocket-III.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.9
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• pp.878-886
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• 2012

This paper investigates the implementation and flight test of realtime vision guided autopilot system based on virtual instrumentation platform. A graphical design process via virtual instrumentation platform is fully used for the image processing, communication between systems, vehicle dynamics control, and vision coupled guidance algorithms. A significatnt ojective of the algorithm is to achieve an environment robust autopilot despite wind and an irregular image acquisition condition. For a robust vision guided path tracking and hovering performance, the flight path guidance logic is combined in a multi conditional basis with the position estimation algorithm coupled with the vehicle attitude dynamics. An onboard flight test equipped with the developed realtime vision guided autopilot system is done using the rotary UAV system with full attitude control capability. Outdoor flight test demonstrated that the designed vision guided autopilot system succeeded in UAV's hovering on top of ground target within about several meters under geenral windy environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.25-32
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• 2006

An advanced method of Relaxed Static Stability (RSS) is utilized for improving the aerodynamic performance of modern version supersonic jet fighter aircraft. The flight control system utilize RSS criteria in both longitudinal and lateral-directional axes to achieve performance enhancements and improve stability. The T-50 advanced trainer employs the RSS concept in order to improve the aerodynamic performance and the flight control law in order to guarantee aircraft stability. The longitudinal two modes are the short period with high frequency and the phugoid mode with low frequency. The design goals of longitudinal control laws is concerned with the short period damping and frequency optimization using lower order equivalent system and utilizing the requirement of MIL-F-8785C. Analysis of short period mode has been and continues to be performed This paper addresses the analysis of aircraft phugoid node characteristics such as damping, natural frequency, and analysis of aircraft pitch motion that impacted by angle of attack limiter and auto pitch attitude control law.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.12
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• pp.1133-1145
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• 2000

In this paper a model following flight control system design using the discrete time quasi-sliding mode control method is described. The quasi-sliding mode is represented as the sliding mode band, not as the sliding surface. The quasi-sliding mode control is composed of the equivalent control for the nominal system without uncertainties and disturbances and the additive control compensating the uncertainties and disturbances. The linearized plant on the equilibrium point is used in designing a flight control system and the stability conditions are proposed for the model uncertainties. Pseudo-state feedback control which uses the model variables for the unmeasured states is proposed. The proposed method is applied to the design of the roll attitude and pitch load factor control of a bank-to-turn missile. The performance is verified through the nonlinear six degrees of freedom flight simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.7
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• pp.589-596
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• 2001

In this paper, a new design methodology for the optimal control of nonlinear systems described by the TS(Takagi-Sugeno) fuzzy model is proposed. First, a new theorem concerning the optimal stabilizing control of a general nonlinear dynamic system is proposed. Next, based on the proposed theorem and the inverse optimal approach, an optimal controller synthesis procedure for a TS fuzzy system is given, Also, it is shown that the optimal controller can be found by solving a linear matrix inequality problem. Finally, the proposed method is applied to the attitude control of a rigid spacecraft to demonstrate its validity.

• Aerospace Engineering and Technology
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• v.8 no.2
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• pp.83-91
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• 2009

This paper concerns the dynamic property of TVC system in the upper stage of KSLV-I. The minimum bandwidth of TVC system is predicted by gathering and comparing the dynamic test data through whole development phases of KSLV-I. The linear models which approximate the dynamic data are also suggested. It is shown that the minimum bandwidth of KSLV-I TVC system is guaranteed over 6.0 Hz at one degree command. It is also shown that the linear model of KSLV-I TVC dynamics takes the form of the transfer function with an 8-th order denominator and a 2-nd order numerator. These results will play an important role in analyzing the flight stability and performance of KSLV-I.