• International Journal of Aeronautical and Space Sciences
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• v.8 no.1
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• pp.10-20
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• 2007

For spacecraft attitude control, reaction wheel (RW) steering laws with more than three wheels for three-axis attitude control can be derived by using a control allocation (CA) approach.1-2 The CA technique deals with a problem of distributing a given control demand to available sets of actuators.3-4 There are many references for CA with applications to aerospace systems. For spacecraft, the control torque command for three body-fixed reference frames can be constructed by a combination of multiple wheels, usually four-wheel pyramid sets. Multi-wheel configurations can be exploited to satisfy a body-axis control torque requirement while satisfying objectives such as minimum control energy.1-2 In general, the reaction wheel steering laws determine required torque command for each wheel in the form of matrix pseudo-inverse. In general, the attitude control command is generated in the form of a feedback control. The spacecraft body angular rate measured by gyros is used to estimate angular displacement also.⁵ Combination of the body angular rate and attitude parameters such as quaternion and MRPs(Modified Rodrigues Parameters) is typically used in synthesizing the control command which should be produced by RWs.¹ The attitude sensor signals are usually corrupted by noise; gyros tend to contain errors such as drift and random noise. The attitude determination system can estimate such errors, and provide best true signals for feedback control.⁶ Even if the attitude determination system, for instance, sophisticated algorithm such as the EKF(Extended Kalman Filter) algorithm⁶, can eliminate the errors efficiently, it is quite probable that the control command still contains noise sources. The noise and/or other high frequency components in the control command would cause the wheel speed to change in an undesirable manner. The closed-loop system, governed by the feedback control law, is also directly affected by the noise due to imperfect sensor characteristics. The noise components in the sensor signal should be mitigated so that the control command is isolated from the noise effect. This can be done by adding a filter to the sensor output or preventing rapid change in the control command. Dynamic control allocation(DCA), recently studied by Härkegård, is to distribute the control command in the sense of dynamics⁴: the allocation is made over a certain time interval, not a fixed time instant. The dynamic behavior of the control command is taken into account in the course of distributing the control command. Not only the control command requirement, but also variation of the control command over a sampling interval is included in the performance criterion to be optimized. The result is a control command in the form of a finite difference equation over the given time interval.⁴ It results in a filter dynamics by taking the previous control command into account for the synthesis of current control command. Stability of the proposed dynamic control allocation (CA) approach was proved to ensure the control command is bounded at the steady-state. In this study, we extended the results presented in Ref. 4 by adding a two-step dynamic CA term in deriving the control allocation law. Also, the strict equality constraint, between the virtual and actual control inputs, is relaxed in order to construct control command with a smooth profile. The proposed DCA technique is applied to a spacecraft attitude control problem. The sensor noise and/or irregular signals, which are existent in most of spacecraft attitude sensors, can be handled effectively by the proposed approach.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.4
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• pp.556-563
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• 2011

Recently, the development of military system is focused on Network Centric Warfare. But, there is no deployed Command and Control System for Missile System in the country. Therefore, Command and Control System for Missile System was simulated to predict feasibility for the future development in this paper. The contents of the design and implementation for simulated system are described in details. Besides, a method for avoiding collisions in 1:N radio communication environment is proposed as the future work. The simulated system in this paper will be a help to developing Command and Control System for Missile System in the future.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.9
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• pp.847-854
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• 2004

In this paper, It is studied to control and to monitor the remote system state using HTTP(Hyper Text Transfer Protocol) object communication. The remote control system is controlled by using a web browser or a application program. This system is organized by three different part depending on functionality-server part, client part, controller part. The java technology is used to composite the server part and the client part and C language is used for a controller. The server part is waiting for the request of client part and then the request is reached, the server part saves client data to the database and send a command set to the client part. The administrator can control the remote system just using a web browser. Remote part is worked by timer that is activated per 1 second. It gets the measurement data of the controller part, and then send the request to the server part and get a command set in the command repository of server part using the client ID. After interpreting the command set, the client part transfers the command set to the controller part. Controller part can be activated by the client part. If send command is transmitted by the client part, it sends sensor monitoring data to the client part and command set is transmitted then setting up the value of the controlled system.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.4
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• pp.34-40
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• 2013

Attitude command response type required for enhanced handling qualities of helicopter can be implemented by mechanical automatic flight control system with SAS actuators which have limited authorities. However, the early saturation of SAS actuator hinders the helicopter from following the attitude command for large stick command. Auto-trim controller can delay SAS actuator's saturation by utilizing trim actuators and allows the attitude command response type for larger stick command. This paper describes the control law for limited authority system of helicopter with auto-trim. Limited authority system is applied to BO-105 linear dynamic model and simulation is performed along with handling quality analysis.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.906-911
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• 1992

We deals with stationary layout control system of AGV. It is a intelligent contorl system to be wholly charged control PC a layout information and guided command and to be controlled a vehicle driving, steening, safety of natural functions of AGV. Fieldbus concentrator of stationary layout control system serves control command from control PC and status information of AGV. Telegram software monitors transmitted command and status information through IR (Infrared) modem. Epecially it is possible to easily network to use not an exclusive controller of AGV but

• 연구논문집
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• s.22
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• pp.27-38
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• 1992

We deals with stationary layout control system of AGV. It is a intelligent control system to he wholly charged control PC a layout information and guided command and to be controlled a vehicle driving, steering, safety of natural functions of AGV. Fieldbus concentrator of stationary layout control system serves control command from control PC and status information of AGV. Telegram software monitors transmitted command and status information through IR(JnfraRed) modem. Especially it is possible to easily network to use not an exclusive controller of AGV but personal computer(PC) when communicate and interface a different kind of controller.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.1
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• pp.88-94
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• 2008

In this paper, a design method of a missile guidance command is presented considering the dynamics of missile control systems. The design of a new guidance command is based on the well-known PNG(propotional navigation guidance) laws. The missile control system dynamics cause the time-delays of the PN guidance command and degrade the performance of original guidance laws which are designed under the assumption of the ideal missile control systems. Using a backstepping method, these time-delay effects can be compensated. In order to implement the guidance command developed by the backstepping procedure, it is required to measure or calculate the successive time-derivatives of the original guidance command, PNG and other kinematic variables such as the relative distance. Instead of directly using the measurements of these variables and their successive derivatives, a simple disturbance observer technique is employed to estimate a guidance command described by them. Using Lyapunov method, the performance of a newly developed guidance command is analyzed against a target maneuvering with a bounded and time-varying acceleration.

• Journal of the Korea Society for Simulation
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• v.20 no.4
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• pp.167-175
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• 2011

Concerning the effectiveness of command and control is increasing worldwide as future warfare is changing into Network Centric Warfare (NCW). Unlike the old attrition warfare that depends mainly on mobility and strike assets, the modern warfare is based on information and network which regards acquisition and circulation of information as important. Therefore, there's no room for rediscussion that C4ISR (Command, Control, Communications, Computers, Intelligence, Surveillance and Reconnaissance) system will play an important role in warfare. In spite of this fact, there isn't any way to explain clearly how to measure the effectiveness of command and control system in a battle and to reflect it systematically in a system effectiveness. In this study, we examined NCO-CF (Network Centric Operations-Conceptual Framework), developed by the Department of Defense (DOD), which can conceptually explain the increment of effectiveness of C4ISR system that is the basis of NCO. And we suggested methodology based on NCO-CF to establish the evaluation criteria for M&S analysis of command and control effectiveness. As a case study we derived the evaluation criteria for the command and control system in joint operations by applying the suggested methodology.

• Journal of the Korean Society of Industry Convergence
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• v.17 no.4
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• pp.217-226
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• 2014

Since the world has changed to a society of 21st century high-tech industries, the modern people have become reluctant to work in a difficult and dirty environment. Therefore, unmanned technologies through robots are being demanded. Now days, effects such as voice, control, obstacle avoidance are being suggested, and especially, voice recognition technique that enables convenient interaction between human and machines is very important. In this study, in order to conduct study on the stable motion control of the robot system that has mobile-manipulator structure and is voice command-based, kinetic interpretation and dynamic modeling of two-armed manipulator and three-wheel mobile robot were conducted. In addition, autonomous driving of three-wheel mobile robot and motion control system of two-armed manipulator were designed, and combined robot control through voice command was conducted. For the performance experiment method, driving control and simulation mock experiment of manipulator that has two-armed structure was conducted, and for experiment of combined robot motion control which is voice command-based, through driving control, motion control of two-armed manipulator, and combined control based on voice command, experiment on stable motion control of voice command-based robot system that has mobile-manipulator structure was verified.

• Convergence Security Journal
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• v.20 no.1
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• pp.69-75
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• 2020

The command control system, like the human brain and nervous system, is a linker that connects the Precision Guided Missile(PGR) in information surveillance and reconnaissance (ISR) and is the center of combat power. In establishing the future command and control system, the ROK military should consider not only technical but also institutional issues. The US Department of Defense establishes security policies, refines them, and organizes them into architectural documents prior to the development of the command and control system. This study examines the security architecture applied to the US military command control system and analyzes the current ROK military-related policies (regulations) to identify security requirements for the future control system. By grouping the identified security requirements, this study identifies and presents field-specific enhancements to existing security regulations.