• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2160-2164
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• 2008

Miniature Joule-Thomson cryocoolers have been widely used for rapid cooling of infrared detectors, probes of cryosurgery, thermal cameras, missile homing head and guidance system, due to their special features of simple configuration, compact structure and rapid cool-down characteristics. The cool-down time, the temperature at the cold end, the running time and the gas consumption are the important indicators of the performance of the J-T cryocooler. In this study, the initial cool-down stages of the J-T cryocooler were investigated by numerical simulations. The results show the effects of the initial charging pressures of gas on the cool-down time and the temperature at the cold end and the gas consumptions.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.12
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• pp.1024-1030
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• 2001

In this paper, a horizontal LOS(line of sight) rate estimator for conventional sea skimming ASM(anti-ship missile) is proposed. A LOS rate dynamics model for a 2-axis gimbal system and the homing geometry is derived. A new LOS rate estimator is proposed by applying the Kalman filter theory to the LOS rate dynamics model. The proposed filter estimates LOS rates by taking roll motions into account. Simulation results show that the proposed filter produces smaller estimation errors than a conventional method.

• Advances in aircraft and spacecraft science
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• v.9 no.1
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• pp.39-57
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• 2022

Instead of developing new guided missiles, converting unguided missile into guided ones by adding guidance and controlkits hasbecome aglobaltrend.Ofthemost efficient andwidelyused thrust vector control(TVC) techniquesin rocketry isthe jet vanes placed inside the nozzle divergentsection. Upon deflecting them, lift created on the vanesistransferred to the rocket generating the desired control moment. The presentstudy examinesthe concept of using an add-on jet vaneTVC kit to a plain nozzle.The impact of adding the kit with different vaneslocations and deflectionanglesisnumericallyinvestigatedbysimulatingtheflowthroughthenozzlewiththekit.Twohingelocations are examined namely, at 24% and 36% of nozzle exit diameter. For each location, angles of deflection namely 0°, 5°, 10°, and 15° are examined. Focus is made on variation of control force, thrust losses, lift and drag on vanes, jet inclination, and jetflow structure withTVCkit design parameters.

• Journal of Biomedical Engineering Research
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• v.35 no.3
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• pp.50-54
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• 2014

It is being tried to control robot arm using brain signal in the field of brain-machine interface (BMI). This study is focused on applying guidance laws for efficient robot arm control using 3D coordinates obtained from Magnetoencephalography (MEG) signal which represents movement of upper limb. The 3D coordinates obtained from brain signal is inappropriate to be used directly because of the spatial difference between human upper limb and robot arm's end-effector. The spatial difference makes the robot arm to be controlled from a third-person point of view with assist of visual feedback. To resolve this inconvenience, guidance laws which are frequently used for tactical ballistic missile are applied. It could be applied for the users to control robot arm from a first-person point of view which is expected to be more comfortable. The algorithm which enables robot arm to trace MEG signal is provided in this study. The algorithm is simulated and applied to 6-DOF robot arm for verification. The result was satisfactory and demonstrated a possibility in decreasing the training period and increasing the rate of success for certain tasks such as gripping object.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.4
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• pp.277-284
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• 2020

The remaining range between missile and target can be used to calculate the guidance command as well as to determine the explosion time of the warhead. Since the range, however, is not directly measured by on-board sensors of the missile, it is usually estimated by filter-based techniques using angle-only measurements. Conventional filter-based techniques are complex and require huge computation. In this paper, we propose a range estimation algorithm based on the geometrical triangulation principle for two points of missiles and a target. The proposed algorithm has a simple structure but the accuracy is largely dependent on the measurement errors. To improve the accuracy of estimation, Digital Fading Memory Filter (DFMF) is applied. The performance of the proposed algorithm is analyzed through numerical simulations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.4
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• pp.324-332
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• 2016

In this paper, the terminal homing loop with a IIR-type strapdown seeker and a roll rate gyroscope is proposed. Basically, the proposed homing loop is based on the look-angle-control guidance. Since the range of the seeker is strictly limited, the missile is delivered to a point to lock the target on the seeker via non-guided flight during the midcourse guidance. The non-standard firing table is developed to compensate the wind and the target movement. To secure the delay margin is very important to prevent the instability of the homing loop when the time delay of the seeker is included. To validate the proposed homing loop, the 6-DOF nonlinear simulation is performed, and the Monte-Carlo simulation is also done for checking the robustness for the various kinds of uncertainty.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.4
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• pp.317-325
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• 2014

For a missile with a strapdown seeker, line-of-sight rate for guidance is obtained by compensating the look angle rate from the strapdown seeker by the body angular rate from rate gyros. However, the body angular rate from rate gyros has different signal properties when it compared to the body angular rate implicitly included in the look angle rate. Typically this discrepancy causes instability of homing loop. In this paper, we propose a design method of homing loop where seeker delay is compulsively placed in the output signal of the rate gyros for accordance of both body rates. Also, PID control loop is considered for obtaining stabilized guidance command even though uncertainties of seeker delay is associated. The stability analysis for the linear homing loop before and after the compensation has been done. The stability and performance of the designed terminal homing loop is verified through full nonlinear 6-DOF simulations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.9
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• pp.742-751
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• 2018

In this paper, we propose a time varying biased proportional navigation guidance law that controls the impact angle under Field-of-View(FOV) and the acceleration limit of the missile. The proposed law is composed of three stages in consideration of the FOV limitation. Since the bias directly affects the acceleration at each stage, the final bias value of the previous stage becomes the initial bias value of the next stage when the stage is switched. In addition, the impact angles were controlled by judging whether impact angles were reached in consideration of engagement conditions and physical constraints.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.58-65
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• 2020

In this paper, the combat effectiveness of ship guidance rockets to counter the threat of multiple USV(Unmanned Surface Vehicle) was analyzed in three cases. The probability of sinking a number of USVs approaching by distance was compared using various weapon systems and guided rocket systems installed on the naval vessels. As a result of the analysis, it was found that the combat effectiveness of the guided rocket was improved compared to the close defense system of the anti-ship missile installed on the naval vessels.

• Advances in aircraft and spacecraft science
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• v.7 no.1
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• pp.1-17
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• 2020

In this paper, a new model-based Fault Detection and Diagnosis (FDD) method for an agile supersonic flight vehicle is presented. A nonlinear model, controlled by a classical closed loop controller and proportional navigation guidance in interception scenario, describes the behavior of the vehicle. The proposed FDD method employs the Inertial Navigation System (INS) data and nonlinear dynamic model of the vehicle to inform fins damage to the controller before leading to an undesired performance or mission failure. Broken, burnt, unactuated or not opened control surfaces cause a drastic change in aerodynamic coefficients and consequently in the dynamic model. Therefore, in addition to the changes in the control forces and moments, system dynamics will change too, leading to the failure detection process being encountered with difficulty. To this purpose, an equivalent aerodynamic model is proposed to express the dynamics of the vehicle, and the health of each fin is monitored by the value of a parameter which is estimated using an adaptive robust filter. The proposed method detects and isolates fins damages in a few seconds with good accuracy.