• 산업경영시스템학회지
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• 제22권50호
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• pp.333-340
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• 1999

An ideal traffic control system should consider simultaneously both route guidance of vehicles and signal policies at intersection of a traffic network. It is known that an iterative procedure gives an optimal route to each vehicle in the network. This paper presents an iterative procedure to find an optimal signal plan for the network. We define the optimal solution as a signal equilibrium. From the definition of signal equilibrium, we prove that the fixed point solution of the iterative procedure is a signal equilibrium, when optimal signal algorithms are implemented at each intersection of the network. A combined model of route guidance and signal planning is also suggested by relating the route guidance procedure and the signal planning procedure into a single loop iterative procedure.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.361-365
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• 1991

The problem being considered here is the determination of optimal guidance laws for a launch vehicle for scientific missions. The optimal guidance commands are determined in the sense that the least amount of fuel is used. A numerical solution was obtained for the case where the position and velocity state variables satisfy a specified constraint at the time of thrust cutoff. The method used here is based on the Pontryagin's maximum principle. This is the method of solving a problem in the calculus of variations. In particular, it applies to the problem considered here where the magnitude of the control is bounded. Simulations for the optimal guidance algorithm, during the 2nd and the 3rd-stage flight of the Japanese rocket M-3H-3, are carried out. The results show that the guided trajectory that satisfying the terminal constraints is optimal, and the guidance algorithm works well in the presence of some errors during the 1st-stage pre-programmed guidance phase.

• International Journal of Aeronautical and Space Sciences
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• 제18권4호
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• pp.709-718
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• 2017

This paper proposes the guidance laws for an agile turn of air-to-air missiles during the initial boost phase. Optimal solution for the agile turn is obtained based on the optimal control theory with a simplified missile dynamic model. Angle-of-attack command generating methods for completion of agile turn are then proposed from the optimal solution. Collision triangle condition for non-maneuvering target is reviewed and implemented for update of terminal condition for the agile turn. The performance of the proposed method is compared with an existing homing guidance law and the minimum-time optimal solution through simulations under various initial engagement scenarios. Simulation results verify that transition to homing phase after boost phase with the proposed method is more effective than direct usage of the homing guidance law.

• 한국항공우주학회지
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• 제35권11호
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• pp.1006-1012
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• 2007

본 논문에서는 호밍 유도 비행체의 종말에서의 충돌각 구속조건을 고려한 준 최적 호밍 유도법칙을 제안한다. 기존의 일반 LQ 최적 제어와는 달리 추가적인 구속조건을 위해 여분의 자유도를 확보하도록 보조 루프를 도입하고, 도입된 부가항을 고려하여 Schwartz 부등식으로부터 최적 제어 입력을 설계한다. 비행체에 인가되는 전체 유도 명령은 최적해와 더불어 부가항을 합성한 준최적 유도법칙의 구조를 갖는다. 또한 제안한 유도법칙의 여러 가지 특성을 고찰하고 기존의 유도법칙들과 비교 연구도 수행한다. 다양한 시뮬레이션 결과를 통하여 제안한 유도법칙의 타당성을 보여준다.

• International Journal of Aeronautical and Space Sciences
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• 제4권2호
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• pp.26-36
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• 2003

The objective of this study is to enhance neural-network guidance to consider the impact condition. The optimal impact condition in this study is defined as an head-on attack. Missile impact-angle error, which is a measure of the degree to which the missile is not steering for a head-on attack, can also have an influence on the final miss distance. Therefore midcourse guidance is used to navigate the missile, reducing the deviation angle from head on, given some constraints on the missile g performance. A coordinate transformation is introduced to simplify the three-dimensional guidance law and, consequently, to reduce training data. Computer simulation results show that the neural-network guidance law with the coordinate transformation reduces impact-angle errors effectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.122-125
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• 2002

The optimal guidance has advantages of accuracy and economic energy consumption but it is difficult to implement due to its dependence on the target information such as the relative range, the relative velocity and the acceleration of target. This paper uses optimal guidance and sliding-mode guidance to obtain a new guidance method. The suggested method shows robustness against target maneuvers, good dynamic performance, energy saving of missile and terminal accuracy. Its effectiveness is demonstrated by the simulation results.

• 한국군사과학기술학회지
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• 제11권4호
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• pp.29-35
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• 2008

In this paper, a new guidance law to reduce sensitivity to the initial heading errors is proposed. In order for shaping the input weights over the flight, we introduce the distribution functions expressed in terms of time-to-go and its inverse term. By applying the optimal control theory with the synthesized weights, the homing guidance law is derived. Also the characteristics of the proposed law are examined. Various computer simulations show the good performance of the proposed guidance.

• Advances in aircraft and spacecraft science
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• 제9권5호
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• pp.433-447
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• 2022

This work deals with an explicit guidance and control architecture for autonomous lunar ascent and orbit injection, i.e., the locally-flat near-optimal guidance, accompanied by nonlinear reduced-attitude control. This is a new explicit guidance scheme, based on the local projection of the position and velocity variables, in conjunction with the real-time solution of the associated minimum-time problem. A recently-introduced quaternion-based reduced-attitude control algorithm, which enjoys quasi-global stability properties, is employed to drive the longitudinal axis of the ascent vehicle toward the desired direction. Actuation, based on thrust vectoring, is modeled as well. Extensive Monte Carlo simulations prove the effectiveness of the guidance, control, and actuation architecture proposed in this study for precise lunar orbit insertion, in the presence of nonnominal flight conditions.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.596-600
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• 1992

In CLOS guidance, feedback compensation of the Coriolis acceleration is used to reduce miss distance. This paper presents the effects of the bandwidth of target and missile on the optimal Coriolis acceleration compensation. A state space formulation of CLOS guidance is used to implement CLOS guidance in feedback form. And the LQR control method is applied to find the optimal feedback gain. From the analysis of the Riccati equations of the optimal control, the following facts are observed: When the target is agile, the optimal gain is reduced, since the compensation becomes ineffective. The missile bandwidth also affects the Coriolis accleration compensation. Narrower missile requires more compensation for the Coriolis acceleration.

• 한국항공우주학회지
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• 제44권3호
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• pp.203-211
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• 2016

BTT 미사일은 STT 미사일과 달리 피치와 롤 채널이 동역학적으로 결합되어 있기 때문에 유도 법칙 개발 시 3차원 추적 기하학을 고려하여야 한다. 기존 연구결과들과는 달리 본 논문에서는 3차원 추적 기하학뿐만 아니라 자동조종장치의 피치와 롤 채널 동역학을 모두 고려한 BTT 미사일의 최적 종말 유도 법칙을 제안한다. 그 결과, 제안하는 유도 법칙은 상대적으로 느린 자동조종장치 동역학에서도 시간 지연 효과로 인한 성능 하락 없이 작은 요격 오차의 높은 요격 성능을 보장한다. 또한, 제안하는 최적 유도 법칙은 잔여 비행시간의 함수를 계수로 하는 궤환 형태로 구해진다. 끝으로 다양한 요격 상황에서의 모의실험을 통해 그 성능을 입증한다.