• International Journal of Automotive Technology
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• 제8권6호
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• pp.723-730
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• 2007

The typical design of automotive driveshafts generally utilizes Constant Velocity(CV) joints as a solution to NVH. CV joints are an integral part of vehicles and significantly affect steering, suspension, and vehicle vibration comfort levels. Thus, CV joints have been favored over universal joints due to the constant velocity torque transfer and plunging capability. Although CV joints are common in vehicle applications, current research works on modeling CV joint friction and assumes constant empirical friction coefficient values. However, such models are long known to be inaccurate, especially under dynamic conditions, which is the case for CV joints. In this paper, an instrumented advanced CV joint friction apparatus was developed to measure the internal friction behavior of CV joints using actual tripod-type joint assemblies. The setup is capable of measuring key performance of friction under different realistic operating conditions of oscillatory speeds, torque and joint installation angles. The apparatus incorporates a custom-installed triaxial force sensor inside of the joint to measure the internal CV joint forces(including friction). Using the designed test setup, the intrinsic interfacial parameters of CV joints were investigated in order to understand their contact and friction mechanisms. The results provide a better understanding of CV joint friction characteristics in developing improved automotive driveshafts.

• 한국자동차공학회논문집
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• 제15권3호
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• pp.114-123
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• 2007

We are going to propose equations for stable static and endurance strength design of driveshafts. It is very important to decide the contact normal stress of internal components of CV joints. We can estimate the strength, torque capacity, endurance life of CV joints from contact normal stress by presented equation in this paper. Besides it can be shown the equation for shaft design.

• 로봇학회논문지
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• 제19권1호
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• pp.1-7
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• 2024

This paper presents an under-actuated robotic hand inspired by the ligamentous structure of the human hand for a prosthetic application. The joint mechanisms are based on the concept of a tensegrity structure formed by elastic strings. These rigid bodies and elastic strings in the mechanism emulate the phalanx bones and primary ligaments found in human finger joints. As a result, the proposed hand inherently possesses compliant characteristics, ensuring robust adaptability during grasping and when interacting with physical environments. For the practical implementation of the tensegrity-based joint mechanism, we detail the installation of the strings and the routing of the driving tendon, which are related to extension and flexion, respectively. Additionally, we have designed the palm structure of the proposed hand to facilitate opposition and tripod grips between the fingers and thumb, taking into account the transverse arch of the human palm. In conclusion, we tested a prototype of the proposed hand to evaluate its motion and grasping capabilities.

• 오토저널
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• 제14권1호
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• pp.13-24
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• 1992

1) 1/2 Scale Model 실험과 실제품 성형실험을 통하여 정밀 냉간단조에 의한 Tripod Slide Housing의 제조공정 설계기술을 확립하고, 4단계 성형공정으로 시제품 제작에 성공하였다. 2) Triod Slide Housing을 성형할 수 있는 4단계(전방압출, Heading, 후방압출, Ironing)의 금형을 설계 및 제작하여 시제품 생산에 적용하고, 관련 필요기술을 축적하였다. 3)XC 48 등 중,고탄소강의 소둔 실험을 통하여 소둔 조건에 따른 구상화율 및 경도의 변화에 대한 연구를 수행함으로써, 고탄소강의 냉간단조시에 필요한 최적 소둔 조건에 응용할 수 있는 자료를 축적하였다.

• Tribology and Lubricants
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• 제28권6호
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• pp.328-332
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• 2012

Generated Axial Force (GAF) due to internal friction at Constant Velocity (CV) joints is one of the causes generating vibration problems such as shudder in vehicle. In this study, the GAF measuring tester is developed to precisely measure GAF caused by internal friction in CV joints. As the developed tester can control temperature at joint, driving torque, angle of rotation and joint angles, actual driving conditions such as sudden acceleration can be applied to the machine. GAFs are measured and compared by using different types of grease in tripod housing. Also GAFs are measured for both new and used CV joints to be compared and analyzed. The test result shows the repeatability and consistency of the tester in terms of the different test conditions. By using the developed CV joint tester, friction performance of the joint can be evaluated by proposing the best CV joints as well as greases generating the lowest GAF.

• 한국지능시스템학회논문지
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• 제19권4호
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• pp.457-463
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• 2009

본 논문에서는 육족 보행 로봇의 새로운 힘 분배 알고리듬을 제안한다. 본 논문에서 고려하는 육족 보행 로봇은 다리 하나에 관절고착고장이 발생하여 내고장성 정적 세다리 걸음새로 보행한다. 제안되는 힘 분배 알고리듬의 핵심은 내고장성 걸음새가 가지는 안정여유도를 결정하는 지지 다리의 미끄러짐을 최소화시키는 것이다. 불연속적으로 움직이는 내고장성 세다리 걸음새는 정상 걸음새보다 안정도가 떨어진다는 약점이 있다. 본 논문에서 제안하는 힘 분배 알고리듬은 이러한 약점을 고려하여 내고장성 걸음새의 지지 다리가 세 개라는 성질과 Zero-Interaction Force 원리를 이용하여 최적화 기법을 쓰지 않고 대수적으로 모든 다리의 힘 성분을 구한다. 컴퓨터 시뮬레이션 사례 연구를 통해서 제안된 힘 분배 알고리듬과 기존 방법의 비교 분석을 실시하고 제안된 방법의 효용성을 입증한다.

• 한국생산제조학회지
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• 제22권4호
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• pp.708-716
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• 2013

This study aims to understand the applied forces and related vibrational characteristics of a tripod joint (TJ), which is mostly used in front-drive-type middle-sized sedans in South Korea. The plunging force (PF) and generated axial force (GAF) are the most influential quantities related to the vibrational characteristics of a driveshaft. To obtain meaningful data, specially designed tests were performed using MTS test sets. The results of direct measurements reveal that higher PF and GAF values appear to worsen the vibrational characteristics of the vehicle. On the other hand, the measured apparent mass is useful for calculating the applied forces for a short driveshaft that has no dynamic vibration absorber. Among diversely controlled samples, it shows that the viscosity and tight fit are very sensitive to shudder vibrations of the vehicle. Therefore, these are good design factors for quality controls in the production line of constant-velocity joints.

• Steel and Composite Structures
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• 제49권2호
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• pp.181-196
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• 2023

Marine structures including offshore wind turbines (OWTs) always work under cyclic loads, which arouses much attention on the fatigue design. The tripod substructure is one of the typical foundation forms for fixed OWTs. The three-planar tubular Y-joint (3Y joint) is one of the important components in fatigue design as it is most likely to have cracks. With the existence of the multiplanar interaction effect, calculating the hot spot stress (HSS) of 3Y joints is complicated. To assist with fatigue design, the distributions of stress concentration factor (SCF) and multiplanar interaction factor (MIF) along weld toe curves induced by the out-of-plane bending moment are explored in this study. An FE analysis method was first developed and verified against experimental results. This method was applied to build a numerical database including 1920 FE models covering common ranges of geometric parameters. A parametric study has been carried out to reveal the distribution patterns of SCF and MIF. After multidimensional nonlinear fittings, SCF and MIF distribution formulas have been proposed. Accuracy and reliability checking prove that the proposed formulas are suitable for calculating the HSS of 3Y joints.

• 전자공학회논문지SC
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• 제43권3호
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• pp.16-24
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• 2006

본 논문에서는 비평탄 지형을 보행하기 위한 육족 보행 로봇의 내고장성 걸음새 계획을 제안한다. 본 논문에서 고려하고 있는 고장은 관절고착고장으로 로봇 다리의 관절 하나가 어떤 위치에 고착되어서 보행이 끝날 때까지 움직일 수 없는 상태를 말한다. 기존에 제안되었던 평탄 지형 보행을 위한 내고장성 세다리 걸음새 계획을 바탕으로 본 논문에서는 육족 보행 로봇이 관절고착고장이 발생한 후에도 이차원 착지 불가능 영역이 존재하는 비평탄 지형을 걸을 수 있도록 하는 내고장성 FTL(Follow-The-Leader) 걸음새를 구현한다. 제안된 FTL 걸음새는 고장 난 다리의 착지점에서 로봇이 가질 수 있는 최대한의 보폭을 낼 수 있으며, 기존 내고장성 걸음새보다 착지 불가능 영역을 뛰어넘는 능력이 더 우수하다. 컴퓨터 시뮬레이션을 통해서 제안된 FTL 걸음새의 응용가능성을 검증한다.

• 한국정밀공학회지
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• 제30권7호
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• pp.694-701
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• 2013

The gear-reduction units of Korean high-speed trains consist of a motor reduction unit, an axle gear box reduction unit, and a tripod joint shaft. A reduction gear unit is a gearbox used to reduce the rotational speed of the input shaft to a slower rotational speed on the output shaft. This reduction in output speed helps to increase torque. Defective reduction gear units in high-speed trains are caused by damage to the gear or by gear fatigue. To diagnose potential problems, it is important to know the vibration characteristics of the reduction gear units. In this study, we analyzed the vibration characteristics of reduction gears under various conditions. The test setup included a full-scale test rig to evaluate reduction gear under both normal and extreme operating conditions.