• 대한기계학회논문집A
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• 제31권5호
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• pp.625-634
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• 2007

KARI SUAV program was initiated to develop a Smart Unmanned Aerial Vehicle with innovative smart technologies. SUAV is a tilt rotor aircraft of which rotor system is 3-bladed, gimbaled hub type. Several existing concepts of gimbaled hub were analyzed and compared to investigate the applicability to SUAV rotor system design. From the result of these investigations, it was concluded that a new design concept of low cost and high reliability characteristics was necessary for the rotor hub development of SUAV. The design requirements of new gimbal hub concept and the design results were presented. Also, the analysis results to verify the satisfaction of design requirements of SUAV rotor system were presented.

• 항공우주기술
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• 제6권2호
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• pp.236-244
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• 2007

스마트무인기의 기본 비행성능 파악과 비행제어 알고리즘의 검증을 위하여 40% 축소형 비행체를 개발하였다. 축소형 비행체는 실물기와 유사한 형태의 짐발 허브와 드라이브 장치를 채택하였으며 강제 공랭 방식의 왕복엔진을 장착하였다. 축소형 비행체 주요 부품에 대한 다양한 시험을 수행하였고 조립된 축소형 비행체의 지상시험 및 호버링 시험을 통하여 주요 성능과 기계적 내구성을 확인하였다.

• 대한기계학회논문집A
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• 제33권8호
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• pp.760-766
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• 2009

In the manufacturing process of HDD, ball swaging method is commonly used to joint the Head Gimbal Assembly(HGA) with the arm of the actuator. The hub on the HGA is placed into the hole of the actuator arm, and the hub and arm is bonded by the pressure of steel ball. The pressure for plastic deformation on the baseplate causes the undesirable deformation on HGA, such as tilting, flying height change of head. After obtaining the key parameters that have large sensitivity on the swaging process, the optimal shape of baseplate is proposed to increase the static performance during swaging process. Contribution of the proposed design for the swaging performance is verified by contact simulation with elasto-plastic deformation.

• 항공우주시스템공학회지
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• 제3권3호
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• pp.17-23
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• 2009

KARI SUAV (Smart Unmanned Aerial Vehicle) program is currently on the phase of ground and flight test. SUAV is a tilt rotor aircraft having the capability of vertical take-off/landing and high speed forward flight. The SUAV rotor system is 3-bladed, gimbaled hub type, which is not common for conventional helicopter configuration. In this paper, detailed procedure and method of rotor pitch rigging, tracking and balancing were described based on the experience of SUAV ground test.

• Tribology and Lubricants
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• 제32권2호
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• pp.61-66
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• 2016

Total thickness variation (TTV), BOW, and surface roughness are essential characteristics for high quality sapphire substrates. Many researchers have attempted to increase removal rate by controlling the key process parameters like pressure and velocity owing to the high cost of consumables in sapphire chemical mechanical polishing (CMP). In case of the pressure approach, increased pressure owing to higher deviation of pressure over the wafer leads to significant degradation of the TTV. In this study, the authors focused on reducing TTV under the high-pressure conditions. When the production equipment polishes multiple wafers attached on a carrier, higher loads seem to be concentrated around the leading edge of the head; this occurs because of frictional force generated by the combination of table rotation and the height of the gimbal of the polishing head. We believe the skewed pressure distribution during polishing to be the main reason of within-wafer non-uniformity (WIWNU). The insertion of a hub ring between the polishing head and substrate carrier helped reduce the pressure deviation. Adjusting the location of the hub ring enables tuning of the pressure distribution. The results indicated that the position of the hub ring strongly affected the removal profile, which confirmed that the position of the hub ring changes the pressure distribution. Furthermore, we analyzed the deformation of the head via finite element method (FEM) to verify the pressure non-uniformity over the contact area Based on experiment and FEM results, we determined the optimal position of hub ring for achieving uniform polishing of the substrate.