Nonsingular adaptive guidance for impact time and angle control

조동수 서울대학교 대학원 2015 국내박사

The ultimate objective of guided missiles is to intercept targets as small miss distance as possible. Most of the guided missiles employ homing guidance which is a guidance process that can acquire the information of the target with respect to the pursuer and can formulate its own commands to guide itself toward the target. Improvements in missile defense systems pose a great challenge in enhancing the survivability and kill probability of conventional homing guided missiles. Moreover, as manervering capabilities of targets evolve, the more agile and accurate performance of missiles with various constraints are required. This dissertation proposes nonlinear guidance laws whose features are divided into four parts: (i) adaptive guidance, (ii) impact angle control guidance, (iii) impact time control guidance, and (iv) impact time and angle control guidance. First, an adaptive guidance law applicable to a short-range homing missile is investigated against a highly maneuvering target that has the same maximum maneuver acceleration as the missile. In practice, it is difficult to measure the target acceleration with precision and without time delay. The objective of this study is to design a guidance law that can intercept a target within the acceptable miss distance in the presence of unknown target acceleration and guidance command saturation. For this, the main idea of this paper is to apply the fast adaptive control approach to estimating the tangential component of the unknown target acceleration. Moreover, the auxiliary signal is introduced to prevent the presence of the guidance command saturation from destroying the desired adaptive performance. The proposed guidance law can be classied as an augmented proportional navigation guidance law with the actual target acceleration component being replaced by its accurate estimate. Second, a sliding mode guidance law for impact angle control is proposed against a maneuvering target with unknown acceleration, which is capable of achieving the acceptable miss distance and a wide range of the desired impact angle. The main idea is to separate the switching surfaces for the impact angle constraint and the homing constraint, then to associate the two surfaces by introducing an appropriate virtual controller. Because of the unknown target acceleration, an adaptive procedure is designed to select the gain of the switching controller which accounts for the uncertainty bound regarding the target acceleration. The stability of the proposed approach is analyzed by Lyapunov theory, and the capturability analysis is also presented. A guidance problem for impact time control applicable to salvo attacks is considered based on the sliding mode control. To prevent the singularity of the guidance command, a positive continuous nonlinear function of the lead angle is introduced to the guidance command, which makes the Lyapunov stability negative semi-denite. This issue is also resolved by the additional component of the guidance command, which makes the sliding mode the only attractor still without the singularity. The capturability analysis is presented, which is not dependent on the initial launching conditions and can guarantee a wide range of the capture region. The proposed guidance law is easily extended to a non-maneuvering and low-maneuvering target using the predicted interception point. A nonsingular guidance law for impact time and angle control applicable to more eective salvo attacks is proposed by combining the impact angle control guidance and impact time control guidance mentioned above. To incorporate two constraints, the guidance system forms an underactuated system. To deal with this, time-varying slack variables are introduced to form a square system. By introducing a positive continuous nonlinear function of the singular point, the singularity problem of the guidance command is prevented. The presented capturability results are independent on the initial launching conditions of missiles, which can guarantee a wide range of the capture region. The proposed guidance law is easily extended to a non-maneuvering and small maneuvering target using the predicted interception point.

군집 자폭형 무인항공기를 이용한 다목적 최적화 기반 동시 공격 유도 알고리즘 연구

이민재 한서대학교 대학원 2026 국내석사

본 논문에서는 소형 고정익 형상의 군집 자폭형 무인항공기를 이용한 다목적최적화 기반 동시 공격 유도 알고리즘을 제안한다. 제안한 알고리즘은 군집 운용시 요구되는 핵심 목적을 달성함으로써 목표물을 효과적으로 타격하는 것을 목표로 한다. 동시 공격은 다수의 자폭형 무인항공기가 목표물을 동시에 타격하도록 유도하는 운용 개념이며, 이를 구현하기 위해 충돌시간 제어 유도(Impact Time Control Guidance, ITCG)가 널리 활용된다. 그러나 ITCG는 충돌각을 명시적으로 제어하기 어렵다는 한계가 있다. 이에 본 논문에서는 원하는 충돌각을 만족하면서도 동시 타격을 구현하기 위해 충돌시간과 충돌각 제어 유도(Impact Time and Angle Control Guidance, ITACG)를 적용한다. 또한 본 논문에서는 동시 공격 과정에서 요구되는 목적을 무인항공기 간 충돌방지, 목표물 할당, 피해량 극대화의 세 가지로 정의한다. 충돌 방지를 위해 안전거리 기반 시간차와 안전충돌고도각을 도입하여 기체 간 충돌을 방지하도록 구성한다. 시간차가 과도하게 증가할 경우 동시 공격 효율이 저하될 수 있으므로, 동시성과 안전성을 동시에 고려할 수 있도록 최적의 시간차를 산출하도록 설계한다. 목표물 할당은 목표물 중요도와 무인항공기별 피해 확률을 반영하여 제한된 자원을 효율적으로 할당할 수 있도록 구성한다. 마지막으로 피해량 극대화를 위해 충돌방위각을 분산시켜 목표물을 타격함으로써 기대 피해 효과가 향상되도록 설계한다. 상기 목적을 기반으로 세 가지 목적함수를 정의하고 관련 제약조건을 설정한다. 정의한 다중 목적함수를 최적화하기 위해 다목적 최적화 알고리즘 중 하나인 비지배적 정렬 유전 알고리즘 II(Non-dominated Sorting Genetic Algorithm-II, NSGA-II)를 적용한다. NSGA-II는 가중치 설정 없이 복수 목적함수를 효과적으로 처리할 수 있으며, 다양한 후보해를 유지하면서 분포가 우수한 파레토 전선을생성할 수 있다는 장점을 가진다. 도출된 파레토 전선 중에서는 유클리드 거리를적용하여 목적 간 절충이 가장 우수한 해를 선택한다. 마지막으로 선택된 최적변수를 적용하여 3차원 동시 공격 시뮬레이션을 수행하고, 그 결과 무인항공기 간상대 거리를 유지한 상태에서 목표 충돌시간과 충돌각을 만족하며 할당된 목표물을 타격함을 확인함으로써 제안한 알고리즘의 성능을 검증한다. In this paper, we propose a multi-objective optimization-based salvo attack guidance algorithm using loitering munitions in the form of a small fixedwing unmanned aerial vehicle. The salvo attack algorithm proposed in this paper aims to effectively hit the target by solving the problems that occur during swarm operations. The salvo attack algorithm is an algorithm in which multiple loitering munitions simultaneously hit the target. Therefore, Impact Time Control Guidance (ITCG) that enables simultaneous hitting is widely used. However, ITCG has a disadvantage that it can not control the collision angle. Therefore, we use the Impact Time and Angle Control Guidance (ITACG) to simultaneously strike while satisfying the desired impact angle. There are several problems that can occur when operating swarm loitering munitions. In this paper, three problems were identified: collisions between loitering munitions, target assignment, and maximization of damage. In order to prevent collisions between loitering munitions, a safety distance-based time difference and a safety collision elevation angle were set to prevent collisions. If the time difference is large, the salvo attack efficiency decreases, so it is designed to obtain the optimal time difference. Target assignment is designed to efficiently allocate loitering munitions based on the importance of the target and the probability of damage to the loitering munitions. Maximizing the amount of damage is designed to strike the target by effectively dispersing the collision azimuth angle in order to maximize the amount of damage. The above problems were defined as three objective functions based on design points, and constraints were set. In order to optimize the defined multi-objective function, it was optimized using one of the multi-objective optimization algorithms, Non-dominated Sorting Genetic Algorithm-II (NSGA-II). This algorithm is adopted because it can effectively calculate objective functions without weighting elements, maintain various candidate solutions, and generate well-distributed pareto fronts. Among the obtained pareto fronts, the Euclidean distance was applied to derive the most balanced optimal solution. Finally, a 3D simultaneous attack simulation was performed by applying the selected optimal solution. As a result of the simulation, the performance of the algorithm proposed in this paper was verified by confirming that the target was hit while maintaining the relative distance between loitering munitions while satisfying the desired impact time and impact angle

르야프노프 기반 유도탄 3차원 충돌시간 유도법칙

한범구 서울대학교 대학원 2011 국내석사