• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.93-98
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• 1989

This paper describes the application of the recently developed feedback linearization technique to designing a new Command to Line-of-Sight (CLOS) guidance law. We show that the CLOS guidance problem can be formulated as a tracking problem. Then, using the feedback input-output linearization technique, we find a new 3dimensional CLOS guidance law that can assure zero miss distance for a randomly maneuvering target. It sheds light on the feedforward acceleration compensation terms used in the conventional CLOS guidance laws to improve the performance. To illustrate further the significance of our result, simulation results are given.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.1
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• pp.60-66
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• 2002

In this paper, a new target pointing guidance algorithm is proposed by combining the optimal target pointing solution and a simple time-to-Go estimator. Also investigated are some properties of the guidance algorithm which include a relation to conventional PNG, convergence region and convergence trajectories of error states according to the time-to-go estimator gain. Some guidelines for designing the pointing guidance law are commented based on the convergence properties. A design example in the case of large initial heading errors is presented and its performance is investigated by simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.567-571
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• 1992

A guidance loop of the missile system which uses a command to line of sight(CLOS) guidance law is designed based on LQG theory. In the environment of the severe tracking system noise, the system requires small aerodynamic control fin travel and small miss distance simultaneously. Results from a sample airframe shows good performance against a randomly maneuvering target.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.4
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• pp.638-647
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• 1994

This paper describes the real time Hardware-In-the Loop Simulation(HILS) that is an efective tool for design, testing and performance evaluation of the guidanc eflight system. The real time HILS was performed by using a 3-axis flight motion simulator, real time computer, I/O system and flight control system hardware along with the assumed flight trajectory of the guidance flight system. Also, we proved the validity of the real time HILS is the guidance flight system by comparing its simulation results with the software simulation data and telemetry data.

• Journal of Ocean Engineering and Technology
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• v.30 no.1
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• pp.32-43
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• 2016

A UUV needs to have a robust path following performance because of unpredicted current disturbances. Because the desired path of a UUV is usually designed by considering the locations of obstacles or geographical features of the operation region, the UUV should stay on the desired path to avoid damage or loss of the vehicle. However, conventional path following methods cannot deal with strong countercurrent disturbances. Thus, the UUV may deviate from the desired path. In order to avoid such deviation, a backward path following method is suggested. This paper proposes a path following method that combines pure pursuit guidance and nonlinear guidance for the UUV under an unpredicted strong ocean current. For a stable path following system, this paper suggests that the UUV adjust its heading to the current direction using the pure pursuit guidance method when the system is in an unstable region, or the UUV follows the desired path with nonlinear guidance. By combining the pure pursuit guidance and nonlinear guidance, it was possible to overcome the drawbacks of each path following method in the reverse path following case. The efficiency of the proposed method is shown through simulation results compared to those of the pure pursuit method and nonlinear guidance method.

• Journal of Ocean Engineering and Technology
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• v.30 no.3
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• pp.208-213
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• 2016

This paper proposes a potential field-based guidance law for docking a USV (unmanned surface vehicle). In most cases, a USV without side thrusters is an under-actuated system. Thus, there are undockable regions near docking stations where a USV cannot dock to a docking station without causing a collision or backward motion. This paper suggest a guidance law that prevents a USV from enter such a region by decreasing the lateral error to the docking station at the initial stage of the docking process. A Monte-carlo simulation was performed to validate the performance of the proposed method. The proposed method was compared to conventional guidance laws such as pure pursuit guidance and pure/lead pursuit guidance. As a result, the collision angle and lateral distance error of proposed method tended to have lower values compared to conventional methods.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.10
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• pp.814-822
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• 2018

This paper proposes a guidance law for missiles with control time constraint. Because the proposed guidance law is based on a time-to-go polynomial, it has a generalized form. Also, acceleration of the proposed law converges to zero at the end of the control time, which reduces the sensitivity to the time-to-go estimation error and can increase the flight stability when the separation of the missile appears. A prediction method of the time-to-go is proposed for implementing the proposed law, and the possibility of application to the midcourse and terminal guidance phases is dealt with for exoatmospheric interception. The characteristics and performance of the proposed law are analyzed throughout various simulations.

• International Journal of Aeronautical and Space Sciences
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• v.7 no.2
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• pp.137-144
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• 2006

The objective of this paper is to present trajectory guidance and control system with a dynamic inversion for a small unmanned aerial vehicle (UAV). The UAV model is expressed by fixed-mass rigid-body six-degree-of-freedom equations of motion, which include the detailed aerodynamic coefficients, the engine model and the actuator models that have lags and limits. A trajectory is generated from the given waypoints using cubic spline functions of a flight distance. The commanded values of an angle of attack, a sideslip angle, a bank angle and a thrust, are calculated from guidance forces to trace the flight trajectory. To adapt various waypoint locations, a proportional navigation is combined with the guidance system. By the decision logic, appropriate guidance law is selected. The flight control system to achieve the commands is designed using a dynamic inversion approach. For a dynamic inversion controller we use the two-timescale assumption that separates the fast dynamics, involving the angular rates of the aircraft, from the slow dynamics, which include angle of attack, sideslip angle, and bank angle. Some numerical simulations are conducted to see the performance of the proposed guidance and control system.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.4
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• pp.719-728
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• 2017

This paper proposes a synthesis of new guidance law to generate an evasive maneuver against enemy's missile interception while considering its impact angle, acceleration, and field-of-view constraints. The first component of the synthesis is a new function of repulsive Artificial Potential Field to generate the evasive maneuver as a real-time dynamic obstacle avoidance. The terminal impact angle and terminal acceleration constraints compliance are based on Time-to-Go Polynomial Guidance as the second component. The last component is the Logarithmic Barrier Function to satisfy the field-of-view limitation constraint by compensating the excessive total acceleration command. These three components are synthesized into a new guidance law, which involves three design parameter gains. Parameter study and numerical simulations are delivered to demonstrate the performance of the proposed repulsive function and guidance law. Finally, the guidance law simulations effectively achieve the zero terminal miss distance, while satisfying an evasive maneuver against intercept missile, considering impact angle, acceleration, and field-of-view limitation constraints simultaneously.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.5
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• pp.41-47
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• 2002

In this paper, a guidance law applicable to aircraft automatic landing is proposed and its performance is compared with the conventional ILS-type landing approach. The concept of miss distance, which is commonly used in the missile guidance laws, and Lyapunov stability are effectively combined to obtain the landing guidance law. The new landing guidance law is integrated into the existing controller and is applied to the landing approach and flare phases of landing procedure. Numerical simulation results show that the new landing guidance law is a viable alternative to the conventional strategies that directly control the longitudinal deviation or altitude.