• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.4
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• pp.401-411
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• 2022

As the role of high-value air assets(e.g., AWACS, JSTARS, Rivet Joint, E-2) becomes more critical in modern warfare, the air escort for these assets blocking attacks from any potential enemy fighter also becomes vital. Without the escort, the operations of the assets become restricted. However, such an escort is not always possible due to the limited flight time of the escort fighters. In this paper, we introduce an escort tactics for high-value air assets performed by the manned-unmanned teaming composed of a transport aircraft and UAVs(unmanned aerial vehicles). In this tactics, the transport aircraft plays the role of an aircraft carrier, which carries, launches, and retrieves the UAVs. The missions of UAVs in this tactics are to detect and engage enemy fighters. We also introduce the simulation result of this tactics to identify the UAVs' required capabilities and optimal maneuvering.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.4
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• pp.393-399
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• 2010

Recently, a vessel's maneuvering performance is considered to be an important subject as marine pollution from the ships that stranded on a rock becomes more severe. So, IMO(International maritime organization) has adopted Resolution MSC.l37 to enhance international standards of ship's maneuverability. There's more than one way to improve ship's maneuverability. This research focused on improving ship's maneuverability by high-lift rudder. To predict the maneuverability, the numerical simulation model was used. The evaluation of maneuverability was carried out by turning test and zig-zag test. The results obtained with these simulation showed that the high-lift rudder would be effective in improving the turning ability of the ship. But it was clarified that there Has a possibility that course changing ability night become bad through an increase of rudder lift.

• International Journal of Control, Automation, and Systems
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• v.1 no.3
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• pp.315-320
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• 2003

This paper presents a control augmentation system (CAS) based on the dynamic model inversion (DMI) architecture for a highly maneuverable aircraft. In the application of DMI not treating actuator dynamics, significant instabilities arise due to limitations on the aircraft inputs, such as actuator time delay based on dynamics and actuator displacement limit. Actuator input saturation usually occurs during high angles of attack maneuvering in low dynamic pressure conditions. The pseudo-control hedging (PCH) algorithm is applied to prevent or delay the instability of the CAS due to a slow actuator or occurrence of actuator saturation. The performance of the proposed CAS with PCH architecture is demonstrated through a nonlinear flight simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.24.1-24
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• 1996

The development of future aircraft that involves the expanded flight envelop will place increased performance requirements on the design of the flight control system. Maneuvering areas are expanding into flight envelopes characterized by significantly larger levels of modeling uncertainty than encountered in present flight control designs. Conventional flight control techniques that ignore the effects of large parameter variations, modeling uncertainties and nonlinearities, will likely produce designs with poor performance and robustness. Recent advances in modern control theories called advanced control theories, most notably the H$\_$.inf./ synthesis technique, adaptive control and neural network application, offer the promise of a design technique that can produce both high performance and robust controllers for next generation aircraft. This special lecture will survey the recent development in advanced flight control and review the possible application of advanced control theories.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.4
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• pp.17-26
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• 1996

A submerged vehicle which is a nonlinear multivariable system must be designed to be roubst against inner-outer perturbations and hydrodynamic disturbances induces maneuvering operation. But a practical design of motion controller is limited by both mathematical modeling error and linearization errors. Performance of a motion controller based on traditional design method is very poor when the vehicle motion is under wave force distrubacnes near sea surface. Therefore, this ppaer proposes a design method of $^{\infty}$ controller under model uncertainty and sea wave disturbances. performance of the controllers by both computer simulation and HILS (hardwave in the loop simulation) shows that $H^{\infty}$ controller is more robust than PID controller under model uncertainty and high sea state...

• Journal of the Korean Society of Industry Convergence
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• v.18 no.2
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• pp.67-74
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• 2015

Two-wheeled driying mobild robots are precise controlled in terms of linear contol methods without considering the nonlinear dynamical characteristics. However, in the high maneuvering situations such as fast turn and abrupt start and stop, such neglected terms become dominant and heavy influence the overall driving performance. This study describes the nonlinear optimal control method to take advantage of the exact nonlinear dynamics of the balancing robot. Simulation results indicate that the optimal control outperforms in the respect of transient performance and required wheel torques. A design example is suggested for the state matrix that provides design flexibility in the control. It is shown that a well-planned state matrix by reflecting the physics of a balancing robot greatly conrtibutes to the driving performance and stability.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.321-326
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• 2008

The engineering use of CFD is recently extending to the prediction of maneuvering characteristics, response to waves, propeller performance, and so on. The focus of the research is shifting to simulation of more complex processes. Typical examples of such processes are bow or stern slamming, green water problem, propeller cavitation, hull-propeller interaction, or drag reduction by bubble injection. Those processes are characterized by keywords such as high nonlinearity, unsteadiness, multiphase flow. In this paper, two new attempts which have been recently made by the author's research grop are presented. One is the prediction of propeller cavitation and its effect to the ship hull. The others is the application to the drag reduction by use of air bubbles.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.321-326
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• 2008

The engineering use of CFD is recently extending to the prediction of maneuvering characteristics, response to waves, propeller performance, and so on. The focus of the research is shifting to simulation of more complex processes. Typical examples of such processes are bow or stern slamming, green water problem, propeller cavitation, hull-propeller interaction, or drag reduction by bubble injection. Those processes are characterized by keywords such as high nonlinearity, unsteadiness, multiphase flow. In this paper, two new attempts which have been recently made by the author's research group are presented. One is the prediction of propeller cavitation and its effect to the ship hull. The other is the application to the drag reduction by use of air bubbles.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.601-607
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• 2005

This paper describes a hydrodynamic modelling study based on the Feldman's equation to predict the nonlinear and coupled maneuvering characteristics of high speed submarine. The hydrodynamic coefficients set is obtained from the modeling of the cross flow drag force and sail induced vorticity, and the captive model experiments(VPMM and RA test) results used to improved the accuracy. The results contained in this paper will be helpful to predict the behavior of tight turn maneuver and to improve the SOE(Safety Operational Envelope) analysis in case of emergency maneuver.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.10
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• pp.1037-1043
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• 2011

Two-wheeled balancing mobile robots are currently controlled in terms of linear control methods without considering the nonlinear dynamical characteristics. However, in the high maneuvering situations such as fast turn and abrupt start and stop, such neglected terms become dominant and greatly influence the overall driving performance. This paper addresses the SDRE nonlinear optimal control method to take advantage of the exact nonlinear dynamics of the balancing robot. Simulation results indicate that the SDRE control outperforms LQR in the respect of transient performance and required wheel torques. A design example is suggested for the state matrix that provides design flexibility in the SDRE control. It is shown that a well-planned state matrix by reflecting the physics of a balancing robot greatly contributes to the driving performance and stability.