• 드라이브 ㆍ 컨트롤
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• 제21권1호
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• pp.22-30
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• 2024

Gearboxes designed for reciprocating motion operating mechanisms operate under conditions where both the load and speed undergo continuous variations. When conducting durability tests on gearboxes designed for such applications, operating the target gearbox under conditions similar to the intended usage is essential. The gearbox must be operated for the required number of cycles to validate its durability under conditions mirroring its intended usage. This study devised an accelerated test method for gearboxes, which reduces operating angles and operational strokes. The reliability of the accelerated test was verified by comparing the stresses imposed on the gears under general and acceleration conditions through multi-body dynamic simulations. The results confirmed that the maximum contact stress levels under normal and accelerated conditions were within a 0.1% error range, indicating a minimal difference in the gear damage rates. However, a difference in the maximum contact stress results between the normal and accelerated conditions was observed when inertial forces acted on the output shaft due to the operational acceleration of the gearbox. Therefore, when conducting this acceleration test, caution should be exercised to ensure that the operational load on the gearbox, which affects inertia, does not significantly deviate from the conditions observed under normal operating conditions.

• 동력기계공학회지
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• 제18권3호
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• pp.36-41
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• 2014

The structure of a variable liquid column oscillator(a VLCO) is analogous to that of the tuned liquid column damper used to suppress oscillatory motion in large structures like tall buildings and cargo ships. The VLCO is a system absorbing high kinetic energy of accelerated motions of the multiple floating bodies in the effect of air springs occurred by installation of inner air chambers. Thus, VLCO can improve the efficiency of energy than wave energy converters of the activating object type made in Pelamis Company. In this research, the experiment was performed in two models of same draft. The one is that weights were filled, and the other is that water was filled. The numerical results were estimated by assuming that do not exist internal flow, and the results were compared with the results of experiments.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2003년도 추계학술대회 및 정기총회
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• pp.201-206
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• 2003

In clinical practice, CT Angiography is a powerful technique for the visualziation of blood flow in arterial vessels throughout the body. However CT Angiography images of blood vessels anywhere in the body may be fuzzy if the patient moves during the exam. In this paper, we propose a novel technique for removing global motion artifacts in the 3D space. The proposed methods are based on the two key ideas as follows. First, the method involves the extraction of a set of feature points by using a 3D edge detection technique based on image gradient of the mask volume where enhanced vessels cannot be expected to appear, Second, the corresponding set of feature points in the contrast volume are determined by correlation-based registration. The proposed method has been successfully applied to pre- and post-contrast CTA brain dataset. Since the registration for motion correction estimates correlation between feature points extracted from skull area in mask and contrast volume, it offers an accelerated technique to accurately visualize blood vessels of the brain.

• 동력기계공학회지
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• 제16권1호
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• pp.91-97
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• 2012

It is being accelerated to develop environment-friendly vehicles to solve problems on the energy and environment of earth. The electric driving motor commonly installed in these vehicles has the excellent control capability such as fast response and accurate generation to torque control command. Especially, in-wheel motor has the additional merit such as independently driving each wheel in vehicle. Recently, being developed various control algorithm to enhance the safety and stability of vehicle motion using actively the merits of in-wheel motor. In addition to that, being issued the possibility of enhancing the ride comfort and attitude of vehicle motion such as pitching and rolling. In this paper, investigate the theoretical relationship between the braking/driving force and the motion of sprung mass of vehicle and propose the control method to enhance the ride comfort and attitude of vehicle motion. The proposed control method is proved through the simulation with vehicle model provided by TruckSim software which is commercial one and specializes in vehicle dynamics.

• 대한관절경학회지
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• 제1권1호
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• pp.86-90
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• 1997

Good stability and complete range of motion should be the ultimate goal of a rehabilitation program after ACL reconstruction. In previous years. the rehabilitation of the ACL reconstructed knee focused on protecting the new ligament by blocking terminal knee extension, hut, despite good stability, this approach led to numerous postoperative complications. Nowadays, most of surgeons agree the accelerated rehabilitation program based on the concept of ligamentization and clinical experience. Accelerated rehabilitation program consists of maintain of full extension of the knee, early weight bearing and prompt recovery of ROM, and closed kinetic chain exercise. Meeting this goal requires effective communication between-members of the health care team-the physician, physical therapist, atheletic trainer, and the patient. We have to know the importance of rehabilitation, knowlege about the physical therapy, and to introduce for special physical therapist and equipment.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2004년도 정기학술대회
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• pp.335-342
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• 2004

The failures such as flaking, wear, crack and seizing caused by the high contact pressure accompanied with sliding motion between inner or outer ring and ball are potential failures of ball bearing. In this research, we have qualitatively selected the efficient test items through the analysis of the life and potential failures of ball bearing. The bearing's failures are related closely to the whole system in using the bearing. So, the bearing itself requires an estimation of life in order to opreate the system safely. We have tested ten ball bearings. Our research has applied both radial and axial direction force of maximum torque conditions simultaneously for the accelerated life testing. The result is established by employing the weibull plot and compared the predicted life of ball bearing to the experimental result.

• 대한기계학회논문집A
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• 제37권11호
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• pp.1407-1413
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• 2013

하이브리드 굴삭기는 기존 굴삭기와 달리 선회구동계에 유압모터를 대신하여 선회전동기를 사용하고 있다. 하이브리드 굴삭기의 신뢰성을 평가하고 보증하기 위해서는 기계와 전기적인 고장모드가 조합되어 고려되어야 한다. 특히, 하이브리드 굴삭기용 선회감속기는 가혹한 실외환경에서 운용되므로 시작품에 대한 현장작동조건을 고려한 가속수명시험이 수행되어야 한다. 본 연구에서는 선회구동계 중선회감속기에 대한 가속수명시험 기법의 개발을 위하여 FMMA, FMAECA, FTA 및 QFD와 같은 정성적 신뢰성기법을 활용하였고, 개발된 가속조건에 의한 수명시험결과를 유분석 기법 등을 활용 분석하여 평가대상 시료가 목표 신뢰도를 만족함을 확인하였다.

• 한국도로학회논문집
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• 제2권2호
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• pp.139-148
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• 2000

외국의 포장가속시험기는 대부분 아스팔트포장의 시험을 주된 목적으로 개발되었다. 그러나, 국내의 고속도로는 콘크리트포장과 아스팔트포장이 거의 같은 연장을 유지하고 있는 실정으로 콘크리트포장의 활용이 예상되어 콘크리트 포장의 시험을 위한 독자적인 포장가속시험시설의 개발이 요구되고 있다. 따라서 한국의 실정에 알맞은 콘크리트/아스팔트포장 '시험용 포장가속 시험시설'을 개발하기 위하여 1997년부터 1999년 동안의 3년간 연구를 수행하였다. 1차 연도에서는 포장가속시험시설을 제작하는데 필요한 기본적인 사양과 기본 시스템 설계에 관한 기초연구가 이루어 졌고, 2$\sim$3차 년도에는 KALES의 전체구조, 하중작용, 현가장치 및 구동장치 등에 대한 상세설계를 수행하였다. 실모델을 제작하기 전단계로 모형시험기를 만들어 시험을 수행하여 작동성 및 하중분배기구 등을 검토하였다. 피로해석 검토결과 제안된 KALES 시스템은 내구성이 있으며 실제차량을 잘 모사할 수 있는 시험기로 판명되었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.667-672
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• 2004

A modeling method for the modal analysis of cantilever plates undergoing in-plane translational acceleration is presented in this paper. Cartesian deformation variables are employed to derive the equations of motion and the resulting equations are transformed into dimensionless forms. To obtain the modal equation from the equations of motion, the in-plane equilibrium strain measures are substituted into the strain energy expression based on Von Karman strain measures. The effects of two dimensionless parameters (related to acceleration and aspect ratio) on the modal characteristics of accelerated plates are investigated through numerical studies.

• 로봇학회논문지
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• 제4권4호
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• pp.327-333
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• 2009

This paper describe the riding robot system named by "RideBot" which is a riding robot like as a horse. In order to simulate the riding motions, we develope the saddle mechanism which can generate 3 DOF motions including pitch, roll, and bounce movement, and also we controlled the riding motions and the intention of horseman. To generate the riding motions with the bodily sensation, we developed Novel Washout Filter and the algorithms for motion control. And also, we developed some health care service for the health care of horseman. A body state index was proposed that evaluates the personal health state from both the measured physiological variables and the surveyed questions. The physiological variables such as weight, blood pressure, heart rate variability (HRV), accelerated state photoplethysmograph(APG), body fat, and happiness index were measured by the specially designed bio-handle system and survey questions. The efficiency of the proposed ride robot is evaluated in the experiments.