• Advances in aircraft and spacecraft science
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• 제1권4호
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• pp.427-441
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• 2014

Orbit-raising is an important step to place spacecraft from parking orbits into working orbits. Attitude control system design is crucial in the success of orbit-raising. Several text books have discussed this design and focused mainly on the traditional methods based on single-input single-output (SISO) transfer function models. These models are not good representations for many orbit-raising control systems which have multiple thrusters and each thruster has impact on the attitude defined by all outputs. Only one published article is known to use a more suitable multi-input multi-output (MIMO) Euler angle model in spacecraft orbit-raising attitude control system design. In this paper, a quaternion based MIMO model for the orbit-raising attitude control system design is proposed. The advantages of using quaternion based model for orbit-raising control system designs are (a) there is no need for mathematical transformations because the attitude measurements are normally given by quaternion, (b) quaternion based model does not depend on rotational sequences, which reduces the chance of human errors, and (c) the singular point of reduced quaternion model is the farthest from the operational point where linearization is performed. We will show that performance of quaternion model based design will be as good as the performance of Euler angle model based design for orbit-raising problem.

• International Journal of Aeronautical and Space Sciences
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• 제14권1호
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• pp.58-66
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• 2013

This paper addresses the performance of three different types of attitude control systems for the Quad-rotor UAV to perform the flip maneuver. For this purpose, Quad-rotor UAV's 6-DOF dynamic model is derived, and it was used for designing an attitude controller of the Quad-rotor UAV. Attitude controllers are designed by three different methods. One is the open-loop control system design, another is the PD control system design, and the last method is the sliding mode control system design. Performances of all controllers are tested by 6-DOF simulation. In case of the open-loop control system, control inputs are calculated by the quad-rotor dynamic model and thrust system model that are identified by the thrust test. The 6-DOF realtime simulation environment was constructed in order to verify the performances of attitude controllers.

• International Journal of Aeronautical and Space Sciences
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• 제17권4호
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• pp.579-592
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• 2016

CNUSAIL-1, to be launched into low-earth orbit, is a cubesat-class satellite equipped with a $2m{\times}2m$ solar sail. One of CNUSAIL's missions is to deploy its solar sail system, thereby deorbiting the satellite, at the end of the satellite's life. This paper presents the design results of the attitude control system for CNUSAIL-1, which maintains the normal vector of the sail by a 3-axis active attitude stabilization approach. The normal vector can be aligned in two orientations: i) along the anti-nadir direction, which minimizes the aerodynamic drag during the nadir-pointing mode, or ii) along the satellite velocity vector, which maximizes the drag during the deorbiting mode. The attitude control system also includes a B-dot controller for detumbling and an eigen-axis maneuver algorithm. The actuators for the attitude control are magnetic torquers and reaction wheels. The feasibility and performance of the design are verified in high-fidelity nonlinear simulations.

• 제어로봇시스템학회논문지
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• 제14권12호
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• pp.1302-1312
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• 2008

Relaxed Static Stability(RSS) has been applied to improve flight performance of modern version supersonic jet fighters. Flight control systems are necessary to stabilize an unstable aircraft and to provide adequate handling qualities. Also, flight control systems of modern aircraft employ many safety measure to cope with emergency situations such as a pilot unknown attitude flight conditions of an aircraft in night flight-testing. This situation is dangerous because the aircraft can lose if the pilot not take recognizance of situation. The system called the "Pilot Activated Recovery System" or PARS, provided a pilot initiated automatic maneuver capable of an aircraft recoveries in situations of unusual attitudes, speed and altitude. This paper addresses the concept of PARS with AARS(Automatic Attitude Recovery System), ATCS(Automatic Thrust Control System) and MARES(Minimum Altitude Recovery Estimation System), and this control law is designed by nonlinear control law design process based on model of supersonic jet trainer. And, this control law is verified by real-time pilot evaluation using an HQS(Handling Quality Simulator). The result of evaluation reveals that the these systems support recovery of an aircraft unusual attitude and speed, and improve a safety of an aircraft.

• 한국추진공학회지
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• 제19권3호
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• pp.54-64
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• 2015

본 논문에서는 DACS(Divert and Attitude Control System)를 장착한 KV(kill vehicle)의 비선형 가속도 조종루프 설계에 대해서 다룬다. ACS(Attitude Control System)는 받음각을 0으로 유지시키는 추력을 유발시키며, 받음각 제어를 위해 ACS를 제어명령으로 사용하는 궤환선형화 기반 비선형 받음각 조종루프를 제안한다. 받음각이 0인 조건에서는 비행경로각과 자세각이 일치하기 때문에 DCS(Divert Control System)는 유도루프에서 요구하는 측방향 가속도를 직접 생성하도록 제어한다. 이러한 방식에서는 추력에 의한 공력간섭 효과를 최소화 시킬 수 있으며, DCS와 ACS의 운용로직을 단순화 시킬 수 있다. 수치 시뮬레이션을 통해 제안한 기법의 성능을 검증한다.

• International Journal of Aeronautical and Space Sciences
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• 제11권4호
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• pp.303-312
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• 2010

This paper introduces the upper stage attitude control system of KSLV-I, which is the first space launch vehicle in Korea. The KSLV-I upper stage attitude control system consists of two electro-hydraulic actuators and a reaction control system using cold nitrogen gas. A proportional, derivative, and integral controller is designed for the electro-hydraulic thrust vectoring system, and Schmidt trigger ON/OFF controllers are designed for the reaction control system. Each attitude controller is designed to have enough stability margins. The stability and performance of KSLV-I upper stage attitude control system is verified via hardware in the loop tests. Hardware in the loop tests are accomplished for perturbed flight conditions as well as nominal flight condition. The test results show that the attitude control loop of KSLV-I upper stage is very stable and the attitude controllers perform well for all flight conditions. Attitude controllers designed in this paper have been successfully applied to the first flight of KSLV-I on August 25, 2009. The flight test results show that all attitude controllers of the KSLV-I upper stage performed well and satisfied the accuracy specifications even during abnormal flight conditions.

• Journal of Mechanical Science and Technology
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• 제18권2호
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• pp.203-210
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• 2004

Attitude control law design for spacecraft large angle maneuvers is investigated in this paper. The feedback linearization technique is applied to the design of a nonlinear tracking control law. The output function to be tracked is the quaternion attitude parameter. The designed control law turns out to be a combination of attitude and attitude rate tracking commands. The attitude-only output function, therefore, leads to a stable closed-loop system following the given reference trajectory. The principal advantage of the proposed method is that it is relatively easy to produce reference trajectories and associated controller.

• 제어로봇시스템학회논문지
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• 제11권3호
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• pp.233-239
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• 2005

This paper presents the design and evaluation of a tiltrotor attitude controller. The implemented response type of the command augumentation system is Attitude Command Attitude Hold. The controller architecture can alleviate the need for extensive gain scheduling and thus has the potential to reduce development time. The control algorithm is constructed using the feedback linearization technique. And an on-line adaptive architecture that employs a neural network compensating the model inversion error caused by the deficiency of full knowledge tiltrotor aircraft dynamics is applied to augment the attitude control system. The use of Lyapunov stability analysis guarantees boundedness of the tracking error and network parameters. The performance of the controller is evaluated against ADS-33E criteria, using the nonlinear tiltrotor simulation code for Bell TR301 developed by KARI. (Korea Aerospace Research Institute)

• Journal of Mechanical Science and Technology
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• 제17권12호
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• pp.1912-1921
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• 2003

This paper presents a global mode modeling of space structures and a control scheme from the practical point of view. Since the size of the satellite has become bigger and the accuracy of attitude control more strictly required, it is necessary to consider the structural flexibility of the spacecraft. Although it is well known that the finite element (FE) model can accurately model the flexibility of the satellite, there are associated problems : FE model has the system matrix with high order and does not provide any physical insights, and is available only after all structural features have been decided. Therefore, it is almost impossible to design attitude and orbit controller using FE model unless the structural features are in place. In order to deal with this problem, the control design scheme with the global mode (GM) model is suggested. This paper describes a flexible structure modeling and three-axis controller design process and demonstrates the adequate performance of the design with respect to the maneuverability by applying it to a large flexible spacecraft model.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2005년도 한국우주과학회보 제14권1호
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• pp.133-137
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• 2005

우주시스템 연구실에서 개발 중인 HAUSAT-2의 피치모멘텀 바이어스 시스템을 설계하고 성능을 검증하였다. HAUSAT-2의 자세제어시스템은 초기자세획득모드와 정상모드로 분리되어 궤도에서 운용된다. 본 논문은 피치모멘텀 바이어스 시스템을 사용하여 위성이 운용될 경우 각 모드에 따라 자세제어가 가능한 범위를 해석하였고 ,모멘팀 휠 구동에 의하여 발생되는 모멘팀 덤핑 현상에 대하여 연구하였다.