• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.4
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• pp.447-456
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• 2010

The application of a reliable motion simulator can contribute effectively in the evaluation of the performance of a vehicle platform in the development stage of a small unmanned aerial vehicle (UAV). Therefore, the research on a reliable motion simulator can accelerate the development of UAV and decrease the relevant cost. In this paper, the design factors considered in the preliminary design stage of a 6 degree-of freedom motion simulator are defined and the motion range of the simulator is described on the basis of these design factors. The length, acceleration, and the required thrust of actuators with respect to the motion simulator under development are also predicted. The motion range can be increased and a suitable actuator can be selected and produced by applying these results in the manufacturing process of the motion simulator. Thus, the reliability of the motion simulators can be achieved during the actual design operation of the UAV.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.4
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• pp.359-365
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• 2011

A mobile surveillance robot is defined as a surveillance robot system that is mounted on a mobile platform and is used to protect public areas such as airports or harbors from invaders. The mobile surveillance robot that is mounted on a mobile platform consists of a gun module, a camera system module, an embedded control system, and AHRS (Attitude and Heading Reference System). It has two axis control systems for controlling its elevation and azimuth. In order to obtain stable images for targeting invaders, this system requires a stabilizer to compensate any disturbance due to vehicle motion. In this study, a virtual model of a mobile surveillance robot has been created and ADAMS/Matlab simulations have been performed to verify the suitability of the proposed stabilization algorithm. Further, the suitability of the stabilization algorithm has also been verified using a mock-up of the mobile surveillance robot and a 6-DOF (Degree Of Freedom) motion simulator.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.119-122
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• 2007

The sloshing flows in the cargo tank model of a ship are measured by PIV and are analyzed with the results. The measurement system is consisted of a Nd-Yag laser(120mJ, 15Hz). two cameras($1k\;{\times}\;1k$) and a host computer. Four experimental cases were tested for the tank model. in which swaying motions are made by 6 DOF-motion platform. The amplitudes of swaying are 9.76mm and 29.29mm, and the frequencies are 0.633Hz and 0.828Hz. The measurement regions are the vertical plane 50mm away from the front wall of the tank where a pump tower is installed. It was verified that the flow patterns of the sloshing are similar each other when the swaying amplitudes are similar.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.5
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• pp.407-413
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• 2013

This paper deals with the analysis of dynamic characteristics of mooring system of floating-type offshore wind turbine. A spar-type floating structure which consists of a nacelle, a tower and the platform excepting blades, is used to model the floating wind turbine and connect three catenary cables to substructure. The motion of floating structure is simulated when the mooring system is attached using irregular wave Pierson-Moskowitz model. The mooring system is analyzed by changing cable position of floating structure. The dynamic behavior characteristics of mooring system are investigated comparing with cable tension and 6-dof motion of floating structure. These characteristics are much useful to initial design of floating-type structure. From the simulation results, the optimized design parameter that is cable position of connect point of mooring cable can be obtained.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.3
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• pp.475-483
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• 2015

We propose a numerical scheme to simulate the time-domain echo signals at tracking radar for a realistic scenario where an EAD (expendable active decoy) and an airborne target are both in dynamic states. On various scenarios where the target takes different maneuvers, the trajectories of the EAD ejected from the target are accurately calculated by solving 6-DOF (Degree-of-Freedom) equations of the motion for the EAD. At each sampling time of the echo signal, the locations of the EAD and the target are assumed to be fixed. Thus, the echo power from the EAD can be simply calculated by using the Friis transmission formula. The returned power from the target can be computed based on the pre-calculated scattering matrix of the target. In this paper, an IPO (iterative physical optics) method is used to construct the scattering matrix database of the target. The sinc function-interpolation formulation (sampling theorem) is applied to compute the scattering at any incidence angle from the database. A simulator is developed based on the proposed scheme to estimate the echo signals, which can consider the movement of the airborne target and EAD, also the scattering of the target and the RF specifications of the EAD. For applications, we consider the detection probability of the target in the presence of the EAD based on Monte Carlo simulation.

• The Journal of Korea Robotics Society
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• v.12 no.4
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• pp.395-401
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• 2017

In this paper, we introduce a robot-assisted medical diagnostic system that enables remote ultrasound (US) imaging to be applied to the conventional telemedicine, which has been possible only with interviewing or a visual exam. In particular, a master-slave robot system is developed that ultrasonic diagnosis specialist can control the position and orientation of US probe in the remote place. The slave robot is designed to be compact, lightweight, and hand-held so that it can easily transfer to the remote healthcare center. Moreover, 6-degree-of-freedom (DOF) probe motion is possible by the robot design based on Stewart platform. The master device is also based on a similar structure of the slave robot. To connect master and slave system in the wide area network (WAN) environment, a hardware CODEC was developed. In this paper, we introduce the detail of each component and the results of the recent experiments conducted in the remote sites by the developed robotic ultrasound imaging system.

• Journal of the Korea Society of Computer and Information
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• v.24 no.8
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• pp.29-35
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• 2019

This paper proposes a UAV equipped with an automatic control system for educational purposes such as navigation flight or autonomous flight. The proposed UAV is capable of automatic navigation flight and it is possible to control more precisely and delicately than existing UAV which is directly controlled. And it has the advantage that it is possible to fly in a place out of sight. In addition, the user may arbitrarily change the route or route information to use it as an educational purpose for achieving the special purpose. It also allows you to check flight status by shooting a video during flight. For this purpose, it is designed to check the image in real time using 5.8GHz video transmitter and receiver. The flight information is recorded separately and used as data to judge the normal flight after the flight. The result of the paper can be flighted along the coordinates specified using GPS information. Since it can receive real-time video, it is expected to be used for various education purposes such as reconnaissance of polluted area, achievement of special purpose, and so on.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.5
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• pp.455-463
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• 2012

In this study, we calculate dynamic constrained force of tower top and blade root of a floating offshore wind turbine. The floating offshore wind turbine is multibody system which consists of a floating platform, a tower, a nacelle, and a hub and three blades. All of these parts are regarded as a rigid body with six degree-of-freedom(DOF). The platform and the tower are connected with fixed joint, and the tower, the nacelle, and the hub are successively connected with revolute joint. The hub and three blades are connected with fixed joint. The recursive formulation is adopted for constructing the equations of motion for the floating wind turbine. The non-linear hydrostatic force, the linear hydrodynamic force, the aerodynamic force, the mooring force, and gravitational forces are considered as external forces. The dynamic load at the tower top, rotor shaft, and blade root of the floating wind turbine are simulated in time domain by solving the equations of motion numerically. From the simulation results, the mutual effects of the dynamic response between the each part of the floating wind turbine are discussed and can be used as input data for the structural analysis of the floating offshore wind turbine.