• Journal of KSNVE
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• v.2 no.4
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• pp.293-304
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• 1992

Active vibration control is presented with simulation and experiment. Dynamic Data System(DDS) method is used for system modeling and this model is combined with an forecasting control technique to derive a control equation. In the experiment, on-line digital computer monitors structural vibration and calculates control input. The control input is sent to an electromagnetic actuator which cancels the structural vibration. Experiment is performed first with a simple beam setup to demonstrate the effetiveness of this method. This method is then applied to a color laser printer to actively modify the structure. The beam experiment showed vibration reduction of over 60% with one-and two-DOF models. In the printer structure experiment, the first mode of 308 Hz was successfully controlled with a one-DOF model.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.86-94
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• 1997

This paper proposes the robot inverse calibration method using a neural networks. A high-order networks called Pi-Sigma networks has been used. The Pi-Sigma networks uses linear summing units in the hidden layer and product unit in output layer. The inverse calibration model which compensates the diff- erence of joint variables only between measuring value and analytic value about the desired pose(position, orientation) of a robot is proposed. The compensated values are determined by using the weights obtained from the learning process of the neural networks previously. To prove the reasonableness, the SCARA type direct drive robot(4-DOF) and anthropomorphic robot(6-DOF) are simulated. It shows that the proposed calibration method can reduce the errors of the joint variables from .+-. 5 .deg. to .+-. 0.1 .deg. .

• Korean Journal of Computational Design and Engineering
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• v.17 no.5
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• pp.333-341
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• 2012

Modeling and simulation is important for military training. People can feel perspective when stereoscope images are created using multi-channel visualizations. A submarine oscillates when the submarine is just below the surface of the sea, so that the reconnaissance becomes difficult. Also, the operator should read the information of the target within 6 seconds using the periscope. The operator must have experience. To solve these problems, stereoscopic multi-channel visualization has been tested. The iCAVE system of KAIST provides a large-scale screen, 7 PCs, and 14 projectors to create the stereoscope images. To simulate the motion of a submarine just below the ocean surface, a 4-DOF motion platform is used. The motion data is transmitted to the visual system and the motion platform through the UDP protocol. Variety of weather conditions are created using the Vega Prime software. The stereoscopic multi-channel visualization and the motion platform system created a realistic simulation system.

• Magazine of the Korea Institute for Structural Maintenance and Inspection
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• v.17 no.4
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• pp.27-35
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• 2013

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.1
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• pp.1-7
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• 2005

Although the Fourier Transform Infra-Red spectrophotometric Direct on Filter(FTIR-DOF) method is a useful analytical technique for quantifying quartz content in respirable dust samples, a number of analytical problems must be taken into consideration such as, to name only a few, inhomogeneous deposition of particles, level of environmental humidity, uneven surface of the filter, and interfering minerals in the sample. This study was designed to select the most suitable wavelength and proper filter material for the method, and to investigate effects of humidity and inhomogeneous deposition of particles on the filter. Samples of respirable dust, created in a dust chamber containing standard material of quartz, were collected using a cyclone equipped with a 25mm filter as a collection medium. The results were as follows; 1. Among seven (7) commercially available filters tested for the FTIR-DOF method, the DM 800 filter showed the best analytical performance having the lowest background absorbance bands and no overlapping peaks at 799, 779, and $695cm^{-1}$. 2. The variations of absorbance due to humidity ranged from 1.0% to 3.3% for $799cm^{-1}$, 1.0% to 3.3% for $779cm^{-1}$, and 8.9%~20.9% for $695cm^{-1}$ peaks, respectively. The $699cm^{-1}$ peak was proved to be most vulnerble to environmental humidity for quantitative analysis of quartz. 3. As for effects of inhomogeneous deposition of samples, the highest variation of absorbance of 10.9% ($13.5{\mu}g$) was observed when using the 695cm-1. The variations of absorbance from the other two peaks, 799 and $779cm^{-1}$, ranged from 1.2 to 3.2%, and 1.4 to 4.1%, respectively. Therefore, the $799cm^{-1}$ peak was considered to be most reliable for quantitative analysis of quartz. The results of this study suggest that, for quantitative analysis of quartz in the respirable dust samples, use of the $799cm^{-1}$ peak can minimize the influence of environmental humidity and inhomogeneous deposition of particles on the filter. The FTIR-DOF method, if adopted for routine analysis of quartz in the respirable dust samples, could save sample preparation time and efforts substantially and also could increase analytical throughputs. Since use of the $799cm^{-1}$ peak is prone to be affected by interferences in the sample, further research on minimizing the effects is needed.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.9
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• pp.833-839
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• 2010

In this paper, a novel 1 DOF hand rehabilitation robot is proposed in consideration of ADL training for stroke patients. To perform several ADL trainings, the proposed robot can move the thumb part and the part of 4 fingers simultaneously and realize the full ROM (Range of Motion) in grasp. Based on these characteristics, the proposed robot realizes several types of grasp such as cylindrical grasp, lateral grasp, and pinch grasp by using a passive revolute joint that can change the thumb movement direction. The movement of the thumb is driven by a cable mechanism and the part of 4 fingers is moved by a four-bar linkage mechanism.

• Journal of Internet of Things and Convergence
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• v.4 no.2
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• pp.7-11
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• 2018

In this paper, kinematic based walking pattern generation of biped walking robot is reviewed. Biped walking robot should be consisted of 6 Degree of Freedom(DOF) for each leg to walk properly in 3 dimensional circumstance. In this paper, simple structure of biped robot is depicted for walking pattern firstly. After fixing path of ankle of the robot, angle joints are coming from kinematic equatioins. Coordination of joints of a robot was set for dynamic analysis also. So walking pattern of a robot will be designed using dynamic equations of coordination of joint angles. Finally, setting of ankle of robot and pattern generation are key procedures of the robot walking.

• The Journal of Korea Robotics Society
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• v.8 no.4
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• pp.247-255
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• 2013

This paper shows the development of a snake robot (KAEROT-snake V) which consists of 16 1-DOF actuator modules and head module. The modules are connected serially and the joint axis of each module is rotated by $90^{\circ}$ with respect to the previous joint so that the snake robot can move in the 3D space. A tail actuator module includes slip-ring and metal connector. KAEROT-snake IV developed in prior research could move in the 3D space and climb up in a narrow pipe. But its design was not appropriate to the unstructured tough environment and its speed was somewhat slow. A new actuator module is designed to enclose all parts of the module so that any wire is not exposed. The size and weight of the new module was slightly reduced. And the rotation speed and torque of the joint was increased by about twice when compared with pre-module. An embedded controller was developed so small that it can be mounted inside the module. The performance of the developed robot was demonstrated through various locomotion experiments.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.4
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• pp.429-436
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• 2018

The RCS value of maritime ship is indicator of ship's stealth performance and it should be particularly measured for navy ship to ensure survivability on the battlefield. In the design phase of the navy ship, a RCS prediction should be performed to reduce RCS value and achieve ROC(Required Operational Capability) of the ship through configuration control. In operational phase, the RCS value of the ship should be measured for verifying the designed value and obtaining tactical data to take action against enemy missile. During the measurement of RCS for the ship, ship motion can be affected by roll and pitch in accordance with sea state, which should be analyzed into threat elevation from view point of enemy missile. In this paper, we propose a method to measure and analyze RCS of ship in 3-dimensions using a ship motion measuring instrument and a fixed RCS measurement system. In order to verify the proposed method, we conducted a marine experiment using a test ship in sea environment and compared the measurement data with RCS prediction value which is carried by prediction SW($CornerStone^{TM}$) using CAD model of the ship.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.4
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• pp.371-377
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• 2009

In this paper, the dynamic characteristic of vibrating system which has translational and rotational degrees of freedom is studied. The moment of inertia of the system is modeled here as the inerter and the equivalent model to the system is proposed using dynamic stiffness method. It is shown that the size of inerter plays a major role to determine the dynamic characteristic of the system. This two degree of freedom system(DOF) is applied as a dynamic vibration absorber(DVA) to the elimination of single peak of main body. The solution for the undamped DVA is presented in analytical form while the damped DVA is designed using fixed point theory. The numerical examples are presented for verifying the methods.