• 제어로봇시스템학회논문지
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• 제20권12호
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• pp.1217-1224
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• 2014

This paper presents a modified track guidance algorithm for formation flight of multiple UAVs. The suggested guidance algorithm is the spatial version of the first order dynamic characteristics for a time-dependent system so the algorithm is able to generate a path without overshoot to track the desired line. A crucial design parameter is a spatial constant that controls the shape of the convergence to an assigned flight path similarly to a time constant. Reference flight trajectories are designed based on a two-dimensional vehicle model, and the performance of the proposed guidance law is verified by numerical simulation using rigid body UAV dynamics with MATLAB/Simulink Aerosim Blockset.

• 한국항공운항학회지
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• 제13권2호
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• pp.14-26
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• 2005

A tilt-rotor aircraft has various flight modes : helicopter, airplane, and conversion. Each of flight mode has unique and nonlinear flight characteristics. Therefore the gain schedules for whole flight envelope are required for effective flight performance. This paper proposes collective, flap, and nacelle angle scheduler for whole flight envelope of the Smart UAV(Unmanned Air Vehicle) based on CAMRAD(Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics) II analysis results. The scheduler designs are improved so that the pitch attitude angle of helicopter mode was minimized. The range of scheduler are reduced inside of engine performance limits. The conversion corridor and rotor governor are suggested also.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 춘계 학술대회논문집
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• pp.14-16
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• 2007

A critical problem in the integration of stores into new and existing aircraft is the safe separation of the stores from the aircraft at a variety of flight conditions representative of the aircraft flight regime. Typically, the certification of a particular store/aircraft/flight condition combination is accomplished by a flight test. Flight tests are very expensive and do expose the pilot and aircraft to a certain amount of risk. Wind tunnel testing, although less expensive than flight testing, is still expensive. Computational Fluid Dynamics(CFD) has held out the promise of alleviating expensive and risk by simulating weapons separation computationally. The forces and moments on a store at carriage and at various points in the flow field of te aircraft can be computed using CFD applied to the full aircraft and store geometry. This study needs full dynamic characteristics study and flow analysis for securing store separation safety. Present study performs dynamic simulation of store separation with flow analysis using Chimera grid scheme which is usually used for moving simulations.

• 제어로봇시스템학회논문지
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• 제22권9호
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• pp.759-765
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• 2016

This paper presents the principle, dynamics modeling and control, hardware implementation, and flight test result of a hybrid-type unmanned aerial vehicle (UAV). The proposed UAV was designed to provide both hovering and fixed-wing type aerodynamic flight modes. The UAV's flight mode transition was achieved through the attitude transformation in pitch axis, which avoids a complex rotor tilt mechanism from a structural and control viewpoint. To achieve this, a different navigation coordinate was introduced that avoids the gimbal lock in pitch singularity point. Attitude and guidance control algorithms were developed for the flight control system. For flight test purposes, a quadrotor attached with a tailless fixed-wing structure was manufactured. An onboard flight control computer was designed to realize the navigation and control algorithms and the UAV's performance was verified through the outdoor flight tests.

• Journal of Astronomy and Space Sciences
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• 제40권2호
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• pp.79-88
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• 2023

On Aug. 4, 2022, at 23:08:48 (UTC), the Korea Pathfinder Lunar Orbiter (KPLO), also known as Danuri, was launched using a SpaceX Falcon 9 launch vehicle. Currently, KPLO is successfully conducting its science mission around the Moon. The National Aeronautics and Space Administration (NASA)'s Deep Space Network (DSN) was utilized for the successful flight operation of KPLO. A great deal of joint effort was made between the Korea Aerospace Research Institute (KARI) and NASA DSN team since the beginning of KPLO ground system design for the success of the mission. The efficient utilization and management of NASA DSN in deep space exploration are critical not only for the spacecraft's telemetry and command but also for tracking the flight dynamics (FD) operation. In this work, the top-level DSN interface architecture, detailed workflows, DSN support levels, and practical lessons learned from the joint team's efforts are presented for KPLO's successful FD operation. Due to the significant joint team's efforts, KPLO is currently performing its mission smoothly in the lunar mission orbit. Through KPLO cooperative operation experience with DSN, a more reliable and efficient partnership is expected not only for Korea's own deep space exploration mission but also for the KARI-NASA DSN joint support on other deep space missions in the future.

• 한국산업정보학회논문지
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• 제22권5호
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• pp.39-49
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• 2017

인공위성 발사를 위한 우주발사체는 효율적인 비행을 위하여 다단으로 구성이 되며 단분리, 연료점화 및 연소종료 등의 비행이벤트를 거쳐서 임무를 완수하게 된다. 이 과정에서 발사체는 추력이 발생하는 동력비행구간과 추력이 없는 탄도비행구간의 과정을 반복하여 겪게 된다. 이러한 우주 발사체의 비행특성을 하나의 동력학 모델로 표현하기는 어렵기 때문에 다중모델을 사용하는 추적 알고리즘에 대한 연구가 많이 진행되어 왔다. 다중모델 추적 알고리즘을 사용하는 경우에는 추적 성능의 개선을 기대할 수 있지만, 사용할 각 동력학 모델들을 적절히 선정해야 하는 어려움이 있으며 또한 다중모델 사용으로 인해 계산양이 증가하는 단점이 있다. 본 논문에서는 등가속도 모델과 적응형 Singer 모델을 사용하는 두 개의 칼만필터만으로 다양한 비행특성을 가지는 우주발사체를 효과적으로 추적하는 방법을 제안한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1871-1876
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• 2005

In this paper, We present a new nonlinear adaptive control law using a disturbance accommodating control (DAC) observer for a Japanese automatic landing flight experiment vehicle called ALFLEX. A future spaceplane must have ability to deal with greater fluctuations in the stability and control derivatives of flight dynamics, because its flight region is much wider than that of conventional aircraft. In our previous studies, digital adaptive flight control systems have been developed based on a linear-parameter-varying (LPV) model depending on dynamic pressure, and obtained good simulation results. However, under previous control laws, it is difficult to accommodate uncertainties represented by disturbance and nonlinearity, and to design a stable flight control system. Therefore, in this study, we attempted to design a nonlinear adaptive control law using the DAC Observer and inverse dynamic methods. A good tracking property of the obtained system was confirmed in numerical simulation.

• 제어로봇시스템학회논문지
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• 제14권3호
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• pp.254-262
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• 2008

In this paper, we propose an adaptive neural dynamic surface control (DSC) approach with $H_{\infty}$ tracking performance for full dynamics of nonlinear flight systems. It is assumed that the model uncertainties such as structured and unstrutured uncertainties, and external disturbances influence the nonlinear aircraft model. In our control system, self recurrent wavelet neural networks (SRWNNs) are used to compensate the model uncertainties of nonlinear flight systems, and an adaptive DSC technique is extended for the disturbance attenuation of nonlinear flight systems. All weights of SRWNNs are trained on-line by the smooth projection algorithm. From Lyapunov stability theorem, it is shown that $H_{\infty}$ performance nom external disturbances can be obtained. Finally, we present the simulation results for a nonlinear six-degree-of-freedom F-16 aircraft model to confirm the effectiveness of the proposed control system.

• Advances in nano research
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• 제15권6호
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• pp.579-585
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• 2023

This research delves into the intricate dynamics of the flight response exhibited by a golf ball that incorporates nanoparticles with the goal of enhancing its overall quality. The golf ball is meticulously modeled utilizing beam elements, and the impact of nanoparticles is intricately captured through the application of the Halpin-Tsai theory. Employing a numerical solution, the study thoroughly explores the flight response of the golf ball, taking into account the nuanced effects of the embedded nanoparticles. By scrutinizing the aerodynamic characteristics through advanced simulations, this investigation aims to provide valuable insights that could potentially revolutionize the design and performance of golf equipment, offering a pathway towards superior quality and enhanced functionality in the realm of golf ball technology. Results show that increase in the volume percent of nanoparticles, improves the flight response of the golf ball.

• 한국항공우주학회지
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• 제35권9호
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• pp.783-791
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• 2007

FAA AC 120-63 등급 C 또는 FTD 등급 5에 규정된 헬리콥터 모의 비행 훈련장치에 사용될 단일 로터 회전익기의 수학적 모델에 대해 고찰하였다. 선정된 비행 운동 모델의 비행 운동 성능 평가를 통해서 그 유용성을 파악하였다. 이로부터 훈련은 물론 조종 성능시험이 가능한 비행 훈련장치 개발을 통해서 헬리콥터 비행성 평가를 위한 모의 비행 시험환경을 구현하였다.