• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.39-45
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• 2022

In this study, we investigated whether the interference occurring in forming roll surfaces could be eliminated by increasing the radius of the variable section forming rolls. The surfaces of the rolls capable of forming products with different flange heights and bend angles with the bend line tilted at an angle of 1° from the longitudinal axis were created using the general CAD software CATIA. Roll interferences were determined for the change in the forming roll radius. The minimum gaps between the upper and lower roll surfaces were measured for the change in the forming roll radius, and the roll interferences were calculated from the difference between the measured value and the thickness of the product. It was observed that the thickness of the product had a slight effect on the roll interference when the thickness was between 0.8 and 1.2 mm. It was also observed that the roll interference could be eliminated by increasing the roll radius.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.31-38
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• 2008

This Study discussed the roll forming process analysis of levitation rail for urban Maglev vehicle. To verify validity of roll forming process, we analyzed roll forming process for track shoe which is similar to levitation rail. The analysis process was composed of 12 passes and was performed for only 8 passes except overlapping passes. In the variation of temperature with each pass, surface temperature of the structure was cooled from initial $1200^{\circ}C$ to $1010^{\circ}C$ during 30 second before first pass, and central temperature and surface temperature was cooled to $980^{\circ}C$ and $900^{\circ}C$ in final pass, respectively. A length of structure after final pass is about 5 times longer than that before roll forming process. A strain of structure had a higher value in the inner part of the track shoe and show from minimum 2.5 to maximum 6.5. A torque applying on roll appear high in 2, 3 and 4 passes and a maximum value was $27,000ton{\cdot}mm$. Also it was analyzed that a load to the normal direction needs maximum 300ton.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.765-766
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• 2008

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.4
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• pp.38-46
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• 2011

This paper presents roll angle estimator which used Kalman filter. Recently, the uses of the ELSD (Electronic Limited Slip Differential) and TVD(Torque Vectoring Differential) for vehicle yaw control are studied in many researches. However the roll angle can be negative effect of ELSD and TVD control. Therefore the information of roll angle can be used for vehicle yaw control. Moreover it can be used for rollover prevent control. Recently, most of the vehicles use lateral acceleration and yaw rate sensor. In this paper, design of Kalman filter which used lateral acceleration and yaw rate information is developed. In this paper, in order to verify the estimator ability, the CarSim and Matlab/Simulink are used.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.1
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• pp.27-33
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• 2007

The shear spinning has been used to produce thin angled cone of parts, with reduced forming force and enhanced mechanical and surface quality for a good finished part, compared with other method formed parts. So shear spinning technique is used widely in industrial production. Especially shear spinning and flow forming techniques are used frequently in automotive, aerial, defense industry. In this paper, finite element method analysis of shear spinning for a cone shape workpiece is carried out to study effects of forming depth and lead angle on forming force. The axial and radial forces on several forming depth and lead angle conditions are obtained.

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.500-506
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• 2018

In this paper, we considered the one-shot alignment using master inertial navigation system (MINS) and slave inertial navigation system (SINS) in the missile to find the exact posture of a missile. In order to perform one-shot alignment, the tilt angle between MINS and SINS must be obtained, which can be compensated by obtaining the tilt angle between missile round and SINS. The tilt angle was calculated by using the roll rotation of missile round, jig for rotating the missile round and interface structure to measure the horizontal state by using a horizontal angle meter were constructed. As a result of the tilt angle save (TAS) inspection, the tilt angle ${\alpha}$, ${\beta}$, ${\gamma}$ is normal range and it is possible to perform one-shot alignment by compensating this value.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.28-28
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• 2015

현재 인쇄전자 소자 생산을 위해 사용되고 있는 대부분의 그라비아 롤러는 미세 패턴의 보호와 인쇄 중 마찰에 대한 내구성을 향상시키기 위해 경질 크롬 도금 막이 사용되고 있다. 그러나 경질 크롬 도금 막의 경우 구현할 수 있는 경도(~1000 HV)와 이형성, 내마찰(마찰계수: ~ 0.6) 특성 등에 한계가 있다. 이러한 경질 크롬 도금이 적용된 그라비아 롤은 그 수명과 내구성, 구현할 수 있는 인쇄 품질 및 신뢰성 그리고 인쇄처리 속도 등에 있어 여러 문제가 있다. DLC(Diamond Like amorphous Carbon)는 낮은 마찰계수 값인 0.2 이하와 뛰어난 내마모성, 상대재료에 대한 이형성 등을 겸비한 표면강화 기술로 경질 크롬 도금막 대비 우수한 표면 경도(>1,800 HV) 특성을 갖으며, 합성된 DLC 코팅 막의 경우 정밀 인쇄 제판이 요구하는 표면거칠기를 구현할 가능성이 높다는 장점이 있다. 특히 실리콘이 첨가 된 Si-DLC의 경우 표면의 마찰계수를 0.1 이하까지 낮출 수 있는데 닥터블레이드 및 잉크, 인쇄 기재와의 마찰 훼손을 최소화시켜 그라비아 인쇄 롤의 수명을 향상시킬 수 있다. 또한 PECVD 공정을 이용하여 합성한 Si-DLC는 표면거칠기를 10nm 이하의 경면으로 구현할 수 있으며, 높은 접촉각에 의한 우수한 이형성을 통해 미세 패턴 내부에 전자잉크/페이스트가 잔류되는 현상을 억제할 수 있다. 이는 기존 경질 크롬 도금이 적용된 그라비아 롤에서 발생하는 패턴 내 잉크 잔류-고형화와 그에 의한 사용수명 단축현상을 현저히 개선시킬 수 있다.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.131-137
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• 2014

The SUV has a risk of rollover because of the highness of center of mass. In this paper the roll-behavior of a SUV in turning motion is analyzed. Dynamic model of the vehicle on the slope is developed and simulation is carried out using the software ADAMS/Car. The results show that the relational expression between the ground force acting on the tire and the roll motion is well established. It is also identified that the driving state of the vehicle becomes unstable at the lower or upper position of the slope.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.7
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• pp.95-102
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• 2016

Geomagnetic sensors are widely utilized for sensing heading direction of quadrotors. However, measurement from a geomagnetic sensor is easily corrupted by environmental magnetic field interference and roll/pitch directional motion. In this paper, a measurement method of a quadrotor heading direction is proposed for application to yaw attitude control. In order to eliminate roll/pitch directional motion effect, the geomagnetic sensor data is compensated using the roll/pitch angles measured for stabilization control. In addition, yaw-directional angular velocity data from a gyroscope sensor is fused with the geomagnetic sensor data using a complementary filter which is a simple and intuitive sensor fusion method. The proposed method is applied to experiments, and the results are presented to prove validity and effectiveness of the proposed method.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.1
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• pp.26-33
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• 2001

Thrust vector control system is control device which is mounted exit of the nozzle to generate pitch, yaw and roll directional force by deflecting flow direction of the supersonic jet from the nozzle. By obtaining control force, jetvane which is exposed in jet flow is working thermal and aerodynamic load. Axial thrust loss and side thrust is affected by shock patterns and interactions between jetvanes according to jetvane geometry and turning angle. In this study, we designed 6 types of jetvane to evaluate pitch, yaw and roll characteristics of ietvane in supersonic flow, and perform the cold flow test in range of turning angles of jetvanes between $0^{\cire}$ and $25^{\cire}$ by $5^{\cire}$ respectively. Also, calculation is going side by side to analyse flow interaction. Results show that there is no interactions between jetvanes upto turning angle 20$^{\circ}$, chord and lead length ratio is very important parameter to aerodynamic performance and maximum thrust loss is appeard to 17% of axial thrust in roll directional control.