• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.15-16
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.67-68
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• 2013

• Economic and Environmental Geology
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• v.44 no.6
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• pp.493-502
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• 2011

We study the deep structure of Korean Peninsula by estimating Moho depth and crustal thickness from using land and oceanic topography and free-air gravity anomaly data. Based on Airy-Heiskanen isostatic hypothesis, the correlated components between the terrain gravity effects and free-air gravity anomalies by wavenumber correlation analysis(WCA) are extracted to estimate the gravity effects that will be resulted from isostatic compensation for the area. With the resulting compensated gravity estimates, Moho depth that is a subsurface between the crust and mantle is estimated by the inversion in an iterative method with the constraints of 20 seismic depth estimates by the receiver function analysis, to minimize the uncertainty of non-uniqueness. Consequently, the average of the resulting crustal thickness estimate of Korean Peninsula is 32.15 km and the standard deviation is 3.12 km. Moho depth of South Korea estimated from this study is compared with the ones from the previous studies, showing they are approximately consistent. And the aspects of Moho undulation from the respective study are in common deep along Taebaek Mountains and Sobaek Mountains and low depth in Gyeongsang Basin relatively. Also, it is discussed that the terrain decorrelated free-air gravity anomalies inferring from the intracrustal characteristics of the crust are compared to the heat flow distributions of South Korea. The low-frequency components of terrain decorrelated Free-air gravity anomalies are highly correlated with the heat flow data, especially in the area of Gyeongsang basin where high heat flow causes to decrease the density of the rocks in the lower crust resulting in lowering the Moho depth by compensation. This result confirms that the high heat sources in this area coming from the upper mantle by Kim et al. (2008).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.8
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• pp.708-714
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• 1990

This paper has proposed a self-tuning controller for tracking reference trajectory by measuring End-point of arm on robot manipulator whose link is light and flexibls, and proved the perforformance of the algorithm proposed through the computer simulation. As an object of control, a flexible robot manipulator with two-links was selected. As for structure of model, it utilized an assume mode shape method with include travity force and derived a dynaics equation by adapting two kinds of vibration mode of each.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.683-693
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• 2010

In this paper, we propose a new parallel mechanism for the legs of biped robots and the control of the robot's locomotion. A leg consists of two 3-DOF parallel platforms linked serially: one is an orientation platform for a thigh and the other is the 3-DOF asymmetric parallel platform for the shank. The desired locomotion trajectory is generated on the basis of the Gravity-Compensated Inverted Pendulum Mode (GCIPM) in the sagittal direction and the Linear Inverted Pendulum Mode (LIPM) in the lateral direction, respectively. In order to simulate the ground reaction force, a 6-DOF elastic pad model is used underneath each of the soles. The performance and effectiveness of the proposed parallel mechanism and locomotion control are shown by the results of computer simulations of a 12-DOF parallel biped robot using $SimMechanics^{(R)}$.

• The Journal of Korea Robotics Society
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• v.15 no.1
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• pp.48-54
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• 2020

Home robot arms require a payload of 2 kg to perform various household tasks; at the same time, they should be operated by low-capacity motors and low-cost speed reducers to ensure reasonable product cost. Furthermore, as robot arms on mobile platforms are battery-driven, their energy efficiency should be very high. To satisfy these requirements, we designed a lightweight counterbalance mechanism (CBM) based on a spring and a wire and developed a home robot arm with five degrees of freedom (DOF) based on this CBM. The CBM compensates for gravitational torques applied to the two pitch joints that are most affected by the robot's weight. The developed counterbalance robot adopts a belt-pulley based parallelogram mechanism for 2-DOF gravity compensation. Experiments using this robot demonstrate that the CBM allows the robot to meet the above-mentioned requirements, even with low-capacity motors and speed reducers.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.810-815
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• 2004

In this paper, we propose new parallel mechanism of a 3 dimensional biped robot whose each leg is composed of two 3-dof parallel platforms linked serially. This proposed parallel mechanism is able to move freely in the man-made environment and is applied to various fields, such as medical, welfare, and so on. And a total weight of each leg is expected to be lighter than serial linked leg. One side leg consists of a 3-dof orientation platform and 3-dof asymmetric parallel platform. The former consists of three active linear actuators and seven passive joints, and the latter of two active linear actuators, one active rotational actuator and eight passive joints. Thus, there are two kinds of parallel platforms each chain's elements and active joint's positions are different for the biped robot to move freely like a serial link without the kinematics constraints. The effectiveness and the performance of the proposed parallel mechanism and locomotion trajectory are shown in computer simulations with a 12-DOF parallel biped robot.

• 대한공업교육학회지
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• v.34 no.2
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• pp.396-410
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• 2009

The goal of this work is to present an advanced method of an estimation of the Modeling Uncertainties coming up in industrial rigid robot's manipulator and actuators. First, with the given physical robot model, the motion equation was derived. Considering a fictitious model, a new extended motion equation is developed. Based on this extended model, an observer and observer bank are designed for the estimation of modeling uncertainties which are involving the effects of gravity, friction, mass unbalance, and Coriolis which show the nonlinear characteristics in operation states.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.8
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• pp.99-106
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• 2021

Scientists at the International Space Station have been studying space life sciences to prepare for future manned space explorations, and require experimental specimen such as rodents for mass measurement. However, it is challenging to use mass measurement systems in space owing to the errors caused by factors such as mechanical-electronic noise. Therefore, to minimize the measurement errors, we propose a new algorithm called multiple calibration, which divides the mass range and calculates the sample weight by using the correction equation of each interval. We performed tests to evaluate and compare the performance of the proposed method to that of normal methods. As a result, the measurement accuracy improved by over two times using the multiple calibration method. Furthermore, we conducted mass measurements on various samples and confirmed that our method is valid for mass measurements.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.2
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• pp.127-139
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• 2024

This paper discusses a gravity compensation technique designed to reduce wavefront error caused by gravity during the assembly and alignment of satellite multi-band optical sensor. For this study, the wavefront error caused by gravity was analyzed for the opto-mechanical structure of multi-band optical sensor. Wavefront error, an indicator of optical performance, was computed by using the displacements of optics calculated through structural analysis and optical sensitivity calculated through optical analysis. Since the calculated wavefront error caused by gravity exceeded the allocated budget, the gravity compensation technique was required. This compensation technique reduces wavefront error effectively by applying the compensation load to the appropriate position of the housing tube. This method successfully meets the wavefront error budget for all bands. In the future, a gravity compensation equipment applying this technique will be manufactured and used for assembly and alignment of multi-band optical sensor.