• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.389-392
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• 2011

In this study, the engine performance data was extracted and analyzed through the flight test of Smart UAV which is tilt rotor aircraft. The flight test was conducted for the transition flight regime where the tilt angle of prop-rotor varies from 90 degree to 0 degree and vice versa. The engine performance data such as engine power and specific fuel consumption gathered from flight tests were compared well with the results of engine performance analysis program.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.1
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• pp.120-131
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• 2016

The full results of troubleshooting process related to the flight control system of a tilt-rotor type UAV in the flight tests are described. Flight tests were conducted in helicopter, conversion, and airplane modes. The vehicle was flown using automatic functions, which include speed-hold, altitude-hold, heading-hold, guidance modes, as well as automatic take-off and landing. Many unexpected problems occurred during the envelope expansion tests which were mostly under those automatic functions. The anomalies in helicopter mode include vortex ring state (VRS), long delay in the automatic take-off, and the initial overshoot in the automatic landing. In contrast, the anomalies in conversion mode are untrimmed AOS oscillation and the calibration errors of the air data sensors. The problems of low damping in rotor speed and roll rate responses are found in airplane mode. Once all of the known problems had been solved, the vehicle in airplane mode gradually reached the maximum design speed of 440km/h at the operation altitude of 3km. This paper also presents a comprehensive detailing of the control systems of the tilt-rotor unmanned air vehicle (UAV).

• Journal of Aerospace System Engineering
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• v.3 no.2
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• pp.12-19
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• 2009

The research for the fatigue analysis is regarded greatly as important in aerospace field. Moreover, a study on the fatigue characteristic is very actively progressing. In this study, the fatigue life estimation was performed for Flaperon Joint which has FCL(fatigue critical location) of tilt-rotor UAV. The Flaperon Joint should be taken the various loads by several missions profiles of UAV. The fatigue load spectrum of Flaperon Joint is generated by the standard mission segment for the tilt-rotor UAV, and this spectrum is used for the fatigue test and analysis. The in-house fatigue analysis program is applied to calculate the fatigue life based on Stress-Life(S-N) method. The S-N curve is generated from the S-N data of Mil-Handbook by second order polynomial regression method. Moreover, the coefficient of determination is used to ensure how accuracy it has. In addition, the Goodman equation is used to consider the mean stress effect for evaluating more accurate fatigue life. Finally, the result of fatigue analysis is verified by comparing with the fatigue test result for the Flaperon Joint.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.654-659
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• 2007

In this paper, the fatigue load spectrum for tilt rotor UAV is developed and fatigue analysis is achieved for flaperon joint. Tilt rotor UAV has two modes which are helicopter mode when UAV is taking off and landing and fixed wing mode when UAV is cruising. To make fatigue load spectrum, FELIX for helicopter mode and TWIST for fixed wing mode are used. And Fatigue analysis of flaperon joint is achieved using fatigue load spectrum we obtained. When S-N test data are analyzed, we use the Kriging meta model to get probability S-N curve for whole range of material life. The result which is life of flaperon joint obtained by suggested fatigue analysis procedure in this paper is compared with that obtained by MSC/Fatigue.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.3
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• pp.33-45
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• 2007

The collision avoidance maneuver flight simulation for tilt rotor unmanned aerial vehicle was performed by time-accurate numerical integration method based on wind tunnel test data. Five representative collision avoidance maneuvers were simulated under constraints of aerodynamic stall, propulsion power, structural load, and control actuator capability. The collision avoidance performances of the maneuvers were compared by the computed collision avoidance times. The sensitivities of initial flight speed and collision zone shape on the collision avoidance time were investigated. From these results, it was found that the moderate pull-up turn maneuver defined using moderate pitch and maximum roll controls within simulation constraints is the most robust and efficient collision avoidance maneuver under the various flight speeds and collision object shapes in the tilt rotor UAV applications.

• The Journal of Korean Physical Therapy
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• v.35 no.6
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• pp.177-184
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• 2023

Purpose: The purpose of this study was to compare the concurrent validity and test-retest reliability of 'KPIMT Torticollis Protractor', a smart phone and I-pad application for convenient range of motion measurement, and 'Image J', an analysis software with high reliability and validity, according to head tilt and active cervical rotation angle. This was done to determine the clinical utility of 'KPIMT Torticollis Protractor'. Methods: Head tilt and active cervical spine rotation angles of 40 children with congenital muscular torticollis were measured using Image J and KPIMT Torticollis Protractor, respectively. The level of concurrent validity and inter-rater and intra-rater reliability between the two measurement methods were analyzed. Results: For forty participants, the concurrent validity between Image J and KPIMT Torticollis Protractor showed very high validity with ICC of ICC 0.977 (0.995-0.999), 0.994 (0.994-0.998), CV_ME% 0.71-0.72%, SEM% 0.31-0.34%, MDC% 0.86-0.94%. The test-retest intra-rater reliability showed very high reliability ICC 0.911 (0.911-0.966), CV_ME% 0.71%, SEM% 0.34-0.36%, MDC% 0.81-0.94%. The test-retest inter-rater showed very high reliability ICC 0.936 (0.933-0.957), CV_ME% 0.70%, SEM% 0.34-0.35%, MDC% 0.81-0.83%. Conclusion: The KPIMT Torticollis Protractor, a smart phone and IPD application, is a highly reliable and valid device for angle measurement in children with congenital myotonia and can be easily used in clinical practice.

• Journal of Korean Physical Therapy Science
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• v.1 no.1
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• pp.175-185
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• 1994

The purpose of this study was to evaluate and compare the biceps muscles activity at the different angle and direction of the base of support on sitting position in hemiplegic patients. The biceps muscles activity was measured at the $0^{\circ},\;10^{\circ}$ of posterior tilt, $10^{\circ}$ of anterior tilt, $10^{\circ}$ of affected side tilt and $10^{\circ}$ of sound side tilt of the base of support by EMG biofeedback (MYOMED 432. ENLAF NONIUS CO.) In this study, 24 out-patients were evaluated who were treated at Yonsei University Medical College Rhabilitation Hospital. This study was carried out from December 5. 1993 to March 30. 1994. In order to determine the statistical significance of result, the ANOVA, and t-test were applied at the 0.05 level of significance. The results were as follows : 1. The biceps muscles activity of the sound side was no significantly difference at the different angle and direction of the base of support on sitting position(p>0.05). 2. The biceps muscles activity of the affected side was significantly increased at the 100 of sound side tilt and $10^{\circ}$ of posterior tilt of the base of support on sitting position(p<0.05). 3. There was no significantly difference in the change of the biceps muscles activity of the affected side between the affected group and the intact group of propriocetive sense(p>0.05). 4. The change of the biceps muscles activity of the affected side was significantly higer in the group of G 2 spasticity compared to that of G 1, G 1+ spasticity(p<0.05). These results showed that the biceps muscles activity of affected side was significantly increased when the base of support was tilted toward the sounde side and posterior direction on sitting position. In order to prevent the increment of biceps muscle activity, the patients must avoid to sit toward sound side and posterior tilt.

• The Journal of Engineering Geology
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• v.29 no.4
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• pp.565-578
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• 2019

Basic friction angles of Hwangdeung granite, Berea sandstone, Jeongsun marble, Hongcheon gneiss, Pungam shale and Eumseong sandy shale were measured by direct shear test, tilt test and pull test. Characteristics of basic friction angle and the accuracy of test methods were compared and the optimal method in measuring basic friction angle was suggested. Although basic friction angles might be measured accurately by direct shear test, the test apparatus is expensive and procedures are complicated. Tilt tests which is the suggested method for measuring basic friction angle by International Association for Rock Mechanics also provided similar basic friction angles measured by direct shear test. However, the error measured for the same rock type is higher than 7° and values by repeated measurements in one sample show different trends, such as increasing or decreasing or almost constant as measurements continued. The difference measured in one gneiss sample is higher 12°, indicating that tilt test may be not a reliable method for measuring basic friction angle. Not only pull test provided accurate and consistent results under low normal stresses, but also test apparatus is simple and inexpensive and procedure is not complicated, indicating that pull test may be the optimal method for measuring basic friction angle.

• Geomechanics and Engineering
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• v.10 no.2
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• pp.155-174
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• 2016

A total of 104 laboratory model tests on a square footing subjected to eccentrically inclined loads supported by sand reinforced with randomly distributed polypropylene fibers were conducted in order to compare the results with those obtained from unreinforced sand and with each other. For conducting the model tests, uniform sand was compacted in a test box at one particular relative density of compaction. The effect of percentage of reinforcement used, thickness of the reinforced layer, angle of inclination of load to vertical and eccentricity of load applied on various prominent factors such as ultimate load, vertical settlement, horizontal deformation and tilt were investigated. An improvement in ultimate load, vertical settlement, horizontal deformation and tilt of foundation was observed with an increase in the percentage of fibers used and thickness of reinforced sand layer under different inclinations and eccentricities of load. A statistical model using non-linear regression analysis based on present experimental data for predicting the vertical settlement ($s_p$), horizontal deformation ($hd_p$) and tilt ($t_p$) of square footing on reinforced sand at any load applied was done where the dependent variable was predicted settlement ($s_p$), horizontal deformation ($hd_p$) and tilt ($t_p$) respectively.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.441-447
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• 2014

The purpose of this study was to explore differences of spinal stabilization muscle strength between groups classified by BMI for industrial workers. Fifty subjects participated in this study were divided to obesity group(BMI over $25kg/m^2$) and non obesity group(BMI under $25kg/m^2$). Independent t-test was applied for analysis. The results showed the following. There were significant differences in $0^{\circ}$ Forward on sagittal plane, in both $90^{\circ}$ Left, $90^{\circ}$ Right on coronal plane, in $45^{\circ}$ Left Tilt, $45^{\circ}$ Right Tilt on diagonal plane between groups. Last, There were significant differences in an amount of soft lean muscle and an amount of skeletal muscle between groups. These results shows that spinal stabilization muscle strength program for the obese should be considered in sagittal plane, coronal plane, and diagonal plane.