• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.692-695
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• 2000

This paper is concerned with Accuracy Design of LM Guide System in Machine Tools. Elastic deformation of bearing is calculated by Hertz contact theory and motion error of LM block is analyzed. A new algorithm using block stiffness is proposed fur the analysis of motion accuracy of the table. The best advantage of this algorithm is fast analysis speed because it isn't necessary iteration processes for satisfying equilibrium equation of the table. Motion errors of the table analyzed under artificial form error of rail theoretically and experimentally. Only one of two rails is bent by putting a thickness gauge into horizontal direction. This form error of rail is measured by gap sensor against the other rail. Then, motion errors of the table are predicted by proposed new algorithm theoretically and measured by laser interferometer. Measurements are carried out by changing the preload and thickness. The results show that the table motion errors are reduced from 1/2 to 1/60 times than form error of rail according to its height and width. And the effect of preloading is almost negligible.

• Journal of International Academy of Physical Therapy Research
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• v.1 no.2
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• pp.162-168
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• 2010

Low back pain is a common phenomenon among the golfers. In an attempt to understand low back pain, the kinematic changes and golf swing motion analysis has been performed to focus on lumbar spine in pro. golfers. According to the swing pattern, significant variations of the lumbar joint forces and loads has related with muscles activities so the motion analysis of lumbar spine were discussed. The purpose of this study was to analyze motion of lumbar spine and it was to compare joint force during golf swing in pro. golfers. The swing motion of the subjects was tracked using a 3D motion analysis system by Motion Analysis Ltd. and SIMM software. The angle changes of lumbar spine rapidly in vx direction during the top back swing and the finish and in vy direction during the follow through and in vz direction during the down swing and the impact(Subject A). The angle changes of lumbar spine rapidly in vx direction during the top back swing and in vy direction during the down swing, the impact and the follow through and in vz direction during the down swing(Subject B). In conclusion, subject A and B both show sudden angle changes between 1st-3rd lumbar spine and 4th-5th lumbar spine during the stage from address to top back swing which caused by over upper body twisting.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.8
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• pp.953-961
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• 2013

In this study, the analyzed turbine is a 5MW upwind-type wind turbine. This conceptual model was made to compare the results of the numerical analysis program in the IEA Annex23 Subtask2 OC3 project. The numerical analysis program used in this study is FAST developed by NREL and AQWA of ANSYS. Motion characteristics, such as RAO, average motion, significant motion and average amplitude of 1/10 highest motion were obtained through the numerical analysis. The results of the numerical analysis were compared with the results of other numerical analyses and the experimental results, and all the results agreed with one another. The results will help resolve the fundamental design trade-offs between basic floating system concepts.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.8
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• pp.697-702
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• 2001

The ring laser gyro(RLG) has been used extensively in strapdown inertial navigation system(SDINS) because of the apparent of having wide dynamic range, digital output and high accuracy. The dithered RLG system has dynamic motion at sensor level, caused by the dithering motion to overcome the lock-in threshold. In this case, an attitude error is produced by not only the true coning of the vehicle motion but also the pseudo coning of the sensor motion. This paper describes the definition of the multi-frequency coning motion and its noncommutativity error to reject the pseudo coning error produced by the sensor motion such as the dithered RLG. The simulation results are presented to minimize the multi-frequency coning error.

• Journal of the Korean Society for Railway
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• v.8 no.1
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• pp.27-33
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• 2005

This paper presents a development of 6DOF motion platform far a tilting train simulator. The tilting train simulator will be used to verify the tilting electronics and tilting control algorithm which are to be applied the Korean 180km/h tilting train. The tilting train simulator is composed of a 6-axis motion platform, a track generation system, a graphic user interface, and a visualization system with 1600mm-diameter dome screen. In this study, the 6DOF motion platform for a tilting train simulator has been designed and manufactured. The motion platform developed is a motion platform of Stewart type. The inverse kinematic analysis has been performed to determine the length of the links of the platform. Furthermore, the specification of the motors have been evaluated by the equation of motion of the platform.

• Journal of Astronomy and Space Sciences
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• v.20 no.4
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• pp.319-326
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• 2003

The motion of each satellite in a tethered satellite system is non-Keplerian in the Earth's gravitational field. In this paper, the tether perturbation force is formulated and compared with the perturbation force due to the Earth's oblateness. Also, the center of mass motion of the tethered satellite system is analyzed. The tether perturbing force on the one of satellites in a tethered satellite system is much bigger than the Earth's oblateness perturbation. The two-body motion approximation of the center of mass is acceptable to describe the motion of the system, when the libration is small.

• The KSFM Journal of Fluid Machinery
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• v.17 no.4
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• pp.59-70
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• 2014

The motion of birds and insects have been studied and applied to MAV(Micro Air Vehicle) and AUV(Autonomous Underwater Vehicle). Most of AUV research is focused on shape and motion of single hydrofoil. However, double hydrofoil system is mostly used in real physics. This system shows completely different hydrodynamic characteristic to single hydrofoil because of wake interaction. The goal of this study is define the trajectory of wake interaction in double hydrofoil system. Moreover, trust and efficiency of various combined motion will be demonstrated. Symmetry airfoil is used for analysis an hydrodynamic characteristic. Forward wing's plunging and pitching motion is fixed, hide wing's Heaving ratio, Pitch phase shift from forward plunging and Heaving shift is changed. This study provide necessary basic data of motion optimization for double hydrofoil system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.12
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• pp.1433-1441
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• 2009

In multibody dynamic analysis, one of the most important problems is to reduce computation times for real-time simulation. This paper presents the derivation procedure of equations of motion of a 6${\times}$6 autonomous vehicle in terms of chassis local coordinates which do not require coordinates transformation matrix to enhance efficiency for real-time dynamic analysis. Also, equations of motion are derived using the VT(velocity transformation) technique and symbolic computation method coded by MATLAB. The Jacobian matrix of the equations of motion of a system is derived from symbolic operations to apply the implicit integration method. The analysis results were compared with ADAMS results to verify the accuracy and approve the feasibility of real time analysis.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2370-2372
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• 1998

Recently we have developed an active stereo head-eye system with vergence, name it KIST HECter(Head-Eye System with Colored Stero Vision), based on the analysis of human's neck and eye motion at visual behavior. Our HECter is a five degree-of-freedom system composed of pan and tilt motion in neck part and independent vergence motion of binocular cameras and commonly shared elevation axis in eye part. And stereo vision Provides two color image, which are processed by powerful each TMS32080 vision board. The shape and size are designed to be almost same as human face. The ability to vergence has significant importance and gives many beneficial merits. On its mechanical implementation we adapt a non-parallelogram 4-bar linkage mechanism since it provides high accuracy in transfering motion and enables compact and flexible design.