• International Journal of Aeronautical and Space Sciences
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• 제12권3호
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• pp.260-265
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• 2011

In this paper, integrated missile guidance and control systems using time-delay control (TDC) are developed. The next generation missile requires that an interceptor hits the target, maneuvering with small miss-distances, and has lower weight to reduce costs. This is possible if the synergism existing between the guidance and control subsystems is exploited by the integrated controller. The TDC law is a robust control technique for nonlinear systems, and it has a very simple structure. The feature of TDC is to directly estimate the unknown dynamics and the unexpected disturbance using one-step time-delay. To investigate the performance of the integrated controller, numerical simulations are performed as the maneuver of the target. The results show that the integrated guidance and control system has a good performance.

• International Journal of Aeronautical and Space Sciences
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• 제9권2호
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• pp.87-97
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• 2008

Modem anti-ship missiles employ complex and sophisticated guidance laws to hit the target and enhance their survivability by executing additional maneuvers. However, such maneuvers may cause the target to move out of the missile seeker's Field-Of-View (FOV). Maintaining seeker lock-on during an engagement is a critical factor for missile guidance. In this paper, a guidance law switching logic that maintains seeker lock-on and a simple guidance law that keeps the target look angle of the seeker constant is proposed. The proposed method can be used for the terminal homing phase, and can be switched from any kind of guidance laws if a proper switching condition is satisfied. The minimum and maximum flight time calculation method in consideration of the missile maneuver limit and the FOV of the seeker is also provided.

• International Journal of Aeronautical and Space Sciences
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• 제9권2호
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• pp.1-8
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• 2008

This paper presents a real-time algorithm for collision detection, collision avoidance and guidance. Three-dimensional point-mass aircraft models are used. For collision detection, conflict probability is calculated by using the Monte-Carlo Simulation. Time at the closest point of approach(CPA) and distance at CPA are needed to determine the collision probability, being compared to certain threshold values. For collision avoidance, one of possible maneuver options is chosen to minimize the collision probability. For guidance to a designated way-point, proportional navigation guidance law is used. Two scenarios on encounter situation are studied to demonstrate the performance of proposed algorithm.

• International Journal of Aeronautical and Space Sciences
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• 제14권3호
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• pp.272-281
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• 2013

Traffic Collision Avoidance System (TCAS) is designed to enhance safety in aircraft operations, by reducing the incidences of mid-air collision between aircraft. The current version of TCAS provides only vertical resolution advisory to the pilots, if an aircraft's collision with another is predicted to be imminent, while efforts to include horizontal resolution advisory have been made, as well. This paper introduces a collision resolution algorithm, which includes both vertical and horizontal avoidance maneuvers of aircraft. Also, the paper compares between the performance of the proposed algorithm and that of algorithms with only vertical or horizontal avoidance maneuver of aircraft.

• International Journal of Automotive Technology
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• 제7권6호
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• pp.703-714
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• 2006

The growing concern surrounding rollover incidences and consequences of Sports Utility Vehicles(SUV) have prompted to investigate the sensitivity of critical vehicle parameters on rollover. In this paper, dynamic rollover simulation of Sports Utility Vehicles is carried out using a validated nonlinear vehicle model in Matlab/Simulink. A standard model is considered and critical vehicle parameters like CG height, track width and wheel base are varied within chosen specified limits to study its influence on roll behavior during a Fishhook steering maneuver. A roll stability criterion based on Two Wheel Lift Off(TWLO) phenomenon is adopted for rollover propensity prediction. Further dynamic rollover characteristics of the vehicle are correlated with Static Stability Factor(SSF), Roll Stability Factor(RSF) and Two Wheel Lift Off Velocity(TWLV). These findings will be of immense help to SUV chassis designers to determine safety limits of critical vehicle parameters and minimize rollover incidences.

• Tuberculosis and Respiratory Diseases
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• 제63권6호
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• pp.507-510
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• 2007

폐렴의 합병증으로 생긴 기관지 늑막강루의 치료로 최근 들어 비침습적 방법으로 기관지 내시경을 이용한 치료가 보고되고 있지만 그 사용 물질 및 방법은 다양하다. 본 증례에서는 혈관 폐쇄용 코일과 피브린 글루를 사용하여 굴곡형 기관지내시경을 이용하여 치료하였다. 기관지 늑막강루의 크기가 크지 않고 말초 기관지에 위치한다면 본 증례의 치료 방법이 고려될 수 있다.

• Journal of the Korean Data and Information Science Society
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• 제15권3호
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• pp.663-675
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• 2004

A battlefield simulation is the evaluation and analysis of the battlefield area, based on the data for terrain, climate, unit's maneuver and tactics basically required in battlefield simulation. Because it is difficult for the military authorities to collect all of the information perfectly for the reason of communication technology, jamming, and tactics, the military authorities need the future moving status for the target units by using acquired moving information. Therefore, we propose a moving object management system that concurrently provides domain reasoning function for the battlefield simulation. In order to implement the proposed system, we show the data modeling of the moving object for the battlefield simulation, and propose an inference engine using domain rule base and spatiotemporal operation. Also, we analyze the query response rate by inference function to verify domain reasoning of the implemented system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.465-467
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• 1998

A lane change maneuver is a part of lateral control of an automated highway system. Assuming no direct measurement of its position during transition from one lane to another. A vehicle is controlled to follow the virtual desired trajectory using only on-board sensors. This paper investigates the development of a fuzzy controller for automated lateral control during emergencies. The performance of the fuzzy controller is presented at 20m/s for a step lane change and a double lane change. The robustness of fuzzy controller is investigated with respect to change in tire parameters and the number of passengers.

• International Journal of Aerospace System Engineering
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• 제4권2호
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• pp.5-9
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• 2017

In a pressurized fuel supply system of aircraft, a flow passage opening device is required to keep fuel continuously transferred from one tank to the other. The device utilizes balancing weights in order to follow up an acceleration at special conditions such as negative g. It is very difficult to test the device in a real high-speed and high-altitude test since severe test conditions and expensive supports are needed. Therefore, this paper deals with performance analysis of a flow passage opening device through low speed aircraft captive flight tests (CFT) including roll and negative-g maneuvers. It is shown that balancing weights in the device can open the passage in accordance with fuel position.

• 제어로봇시스템학회논문지
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• 제7권7호
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• pp.574-581
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• 2001

In this paper we design and evaluate the longitudinal nonlinear N(aub)z-CSAS(Command and Stability Augmentation System) flight control law in \"DMI(Dynamic Model Inversion)-method\" and classical \"Gain Scheduling-method\", respectively, to meet the handling quality requirements associated with push-over pull-up maneuver. It is told that the flight control law designed in \"DM-method\" is adequate to the full flight regime without gain scheduling and is efficient to produce the time response shape desired to the handling quality requirements. On the contrary, the flight control law designed in \"Gain Scheduling-method\" is easy to be implemented in flight control computer and insensitive to variation of the actuator model characteristics.n of the actuator model characteristics.