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Journal of Aerospace System Engineering
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The Society for Aerospace System Engineering
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Volume 10, Issue 2 - Jun 2016
Volume 10, Issue 1 - Mar 2016
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Numerical analysis on two-dimensional vortex merger
Park, Sanghyun ; Sheen, DongJin ; Chang, Kyoungsik ; Kwag, DongGi ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 1~7
DOI : 10.20910/JASE.2016.10.1.1
During flight of the aircraft, the vortex merging phenomenon appears under the certain condition between co-rotating vortices which were generated at the wing tip and lifting-surface. And then these merged vortices at both sides show counter-rotating pattern to affect on the downstream of the aircraft. In this paper, the numerical simulations are conducted assuming this phenomenon in two-dimensional co-rotating or counter-rotating vortices pairs. Two-dimensional incompressible Navier-Stokes equations were converted into Vorticity-Streamfunction form and the Galerkin spectral method was adopted. The third order Runge-Kutta method was used for time integration. The effects on the vortex merger and degree of vortex merger were investigated according to time, Reynolds number, and changes in the distance between two vortices.
Nonlinear Bearing Only Target Tracking Filter
Yoon, Jangho ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 8~14
DOI : 10.20910/JASE.2016.10.1.8
The optimal estimation of a bearing only target tracking problem be achieved through the solution of the Fokker-Planck equation and the Bayesian update. Recently, a nonlinear filtering algorithm using a direct quadrature method of moments in which the associated Fokker-Planck equation can be propagated efficiently and accurately was proposed. Although this approach has demonstrated its promising in the field of nonlinear filtering in several examples, the "degeneracy" phenomenon, similar to that which exists in a typical particle filter, occasionally appears because only the weights are updated in the modified Bayesian rule in this algorithm. Therefore, in this paper to enhance the performance, a more stable measurement update process based upon the update equation in the Extended Kalman filters and a more accurate initialization and re-sampling strategy for weight and abscissas are proposed. Simulations are used to show the effectiveness of the proposed filter and the obtained results are promising.
Study on Nonlinear Filter Using Unscented Transformation Update
Yoon, Jangho ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 15~20
DOI : 10.20910/JASE.2016.10.1.15
The optimal estimation of a general continuous-discrete system can be achieved through the solution of the Fokker-Planck equation and the Bayesian update. Due the high nonlinearity of the equation of motion of the system and the measurement model, it is necessary to linearize the both equation. To avoid linearization, the filter based on Fokker-Planck equation is designed. with the unscented transformation update mechanism, in which the associated Fokker-Planck equation was solved efficiently and accurately via discrete quadrature and the measurement update was done through the unscented transformation update mechanism. This filter based on the Direct Quadrature Moment of Method(DQMOM) and the unscented transformation update is applied to the bearing only target tracking problem. The proposed filter can still provide more accurate estimation of the state than those of the extended Kalman filter especially when measurements are sparse. Simulation results indicate that the advantages of the proposed filter based on the DQMOM and the unscented transformation update make it a promising alternative to the extended Kalman filter.
Nonlinear Filter for Orbit Determination
Yoon, Jangho ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 21~28
DOI : 10.20910/JASE.2016.10.1.21
Orbit determination problems have been interest of many researchers for long time. Due to the high nonlinearity of the equation of motion and the measurement model, it is necessary to linearize the both equations. To avoid linearization, the filter based on Fokker-Planck equation is designed. with the extended Kalman filter update mechanism, in which the associated Fokker-Planck equation was solved efficiently and accurately via discrete quadrature and the measurement update was done through the extended Kalman filter update mechanism. This filter based on the DQMOM and the EKF update is applied to the orbit determination problem with appropriate modification to mitigate the filter smugness. Unlike the extended Kalman filter, the hybrid filter based on the DQMOM and the EKF update does not require the burdensome evaluation of the Jacobian matrix and Gaussian assumption for the system, and can still provide more accurate estimations of the state than those of the extended Kalman filter especially when measurements are sparse. Simulation results indicate that the advantages of the hybrid filter based on the DQMOM and the EKF update make it a promising alternative to the extended Kalman filter for orbit estimation problems.
Computation of Unsteady Aerodynamic Forces in the Time Domain for GVT-based Ground Flutter Test
Lee, Juyeon ; Kim, Jonghwan ; Bae, Jaesung ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 29~34
DOI : 10.20910/JASE.2016.10.1.29
Flutter wind-tunnel test is an expensive and complicated process. Also, the test model may has discrepancy in the structural characteristics when compared to those of the real model. "Dry Wind-Tunnel" (DWT) is an innovative testing system which consists of the ground vibration test (GVT) hardware system and software which computationally can be operated and feedback in real-time to yield rapidly the unsteady aerodynamic forces. In this paper, we study on the aerodynamic forces of DWT system to feedback in time domain. The aerodynamic forces in the reduced-frequency domain are approximated by Minimum-state approximation. And we present a state-space equation of the aerodynamic forces. With the two simulation model, we compare the results of the flutter analysis.
Performance Analysis of Reaction Wheel according to Bearing Preload and Oil Quantity
Kim, Jichul ; Yoon, Jinhyuk ; Lee, Junyong ; Oh, Hwasuk ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 35~42
DOI : 10.20910/JASE.2016.10.1.35
Bearing friction and disturbance are the important parameters in control spacecraft using reaction wheel. In this paper, those parameters are estimated by preload and oil quantity. In order to determine the bearing preload's impact on performance, measure the disturbance and the bearing friction coefficient with increasing the preload to the allowed amount. And, find the relationship between oil quantity and bearing friction coefficient, measure it with increasing the oil amount in the bearing. With these results as a reference, find the appropriate amount of preload and oil quantity.
A Study on Manufacturing Methods of Cocuring Composite Wings of Solar-Powered UAV
Yang, Yongman ; Kwon, Jeongsik ; Kim, Jinsung ; Lee, Sooyong ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 43~50
DOI : 10.20910/JASE.2016.10.1.43
In order to suggest the optimal manufacturing technology of composite wings of solar-powered unmanned aerial vehicles, this study compared forming technologies to reduce wing weight for long-endurance flight and to improve the manufacturing process for cost-saving and mass production. It compared the manufacturing time and weight of various composite wing molding technologies, including cocuring, secondary bonding, and manufacturing by balsa. As a result, wing weight was reduced through cocuring methods such as band type composite fiber/tape lamination technology, which enabled prolonged flight duration. In addition, the reduced manufacturing time led to a lower cost, which is a good example of weight lightening for not only small solar-powered UAVs, but also composite aircraft.
No-Failure Accelerated Life Test of Flap Actuating System using Weibull Distribution
Cho, Hyunjun ; Lee, Inho ; Kim, Sangbeom ; Park, Sangjoon ; Yang, Myungseok ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 51~58
DOI : 10.20910/JASE.2016.10.1.51
In this paper, we present some results on No-failure accelerated life test of aerial vehicle for reliability demonstration. The design of general accelerated life test consists of the three phases: 1) Estimating normal life test time of a single product from Weibull distribution model; 2) Determining the acceleration factor (AF) by utilizing the relation between the life of mechanical components and the applied torque; 3) Calculating the accelerated life test time, which comes from dividing the estimated normal life test time into AF. Then, we applied the calculated life test time to the real reliability test of the flap actuating system, while considering the requirement specification for mechanical components and operating environment of the actuation system. Real experimental processes and results are presented to validate the theory.
Developing High Altitude Long Endurance (HALE) Solar-powered Unmanned Aerial Vehicle (UAV)
Hwang, SeungJae ; Kim, SangGon ; Lee, YungGyo ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 59~65
DOI : 10.20910/JASE.2016.10.1.59
Korea Aerospace Research Institute (KARI) is developing an electric-driven HALE UAV in order to secure system and operational technologies since 2010. Based on the 5 years of flight tests and design experiences of the previously developed electric-driven UAVs, KARI has designed EAV-3, a solar-powered HALE UAV. EAV-3 weighs 53 kg, the structure weight is 21 kg, and features a flexible wing of 19.5 m in span with the aspect ratio of 17.4. Designing the main wing and empennage of the EAV-3 the amount of the bending due to the flexible wing, 404 mm at 1-G flight condition based on T-800 composite material, and side wind effects due to low cruise speed, V_cr = 6 m/sec, are carefully considered. Also, unlike the general aircraft there is no center of gravity shift during the flight. Thus, the static margin cuts down to 28.4% and center of gravity moves back to 31% of the Mean Aerodynamic Chord (MAC) comparing to the previously developed scale-down HALE UAVs, EAV-2 and EAV-2H, to minimize a trim drag and enhance a performance of the EAV-3. The first flight of the EAV-3 has successfully conducted on the July 29, 2015 and the test flight above the altitude 14 km has efficiently achieved on the August 5, 2015 at the Goheung aviation center.
A Review on Major Foreign Research Trend of Monomethylhydrazine Reaction for Space Propulsion Part I : Thermal Decomposition Reaction of Monomethylhydrazine
Jang, Yohan ; Lee, Kyun Ho ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 66~73
DOI : 10.20910/JASE.2016.10.1.66
Space propulsion system produces required thrust for satellites and space launch vehicles by using chemical reactions of a liquid fuel and a liquid oxidizer typically. For example, monomethylhydrazine-dinitrogen tetroxide, liquid hydrogen-liquid oxygen and RP-1-liquid oxygen are conventional combinations of liquid propellants used for the liquid propulsion system. Among several liquid propellants, the monomethylhydrazine is expecially preferred for a satellite fuel due to its better storability in liquid phase during a relatively long mission period under a space environment. Thus, a development importance of a bipropellant system using the monomethylhydrazine fuel is recognized recently as the national space program proceeds on a large scale. The objective of the present study is to review a foreign research trend of a thermal decomposition reaction of monomethyhydrazine to understand a fundamental basis of its chemical reaction to prepare for domestic development in future.
A Review on Major Foreign Research Trend of Monomethylhydrazine Reaction for Space Propulsion Part II : Chemical Reaction of Monomethylhydrazine-Dinitrogen Tetroxide
Jang, Yohan ; Lee, Kyun Ho ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 74~81
DOI : 10.20910/JASE.2016.10.1.74
Space propulsion system produces required thrust for satellites and space launch vehicles by using chemical reactions of a liquid fuel and a liquid oxidizer typically. Among several liquid propellants, the monomethylhydrazine-dinitrogen tetroxide is expecially preferred for a GEO satellite propellants due to their better storability in liquid phase during a long mission life under a freezing space environment. Recently, a development of the monomethylhydrazine-dinitrogen tetroxide bipropellant system becomes important as the national space program requires the heavier and the more efficient space system. Thus, the objective of the present study is to review a foreign research trend of a chemical reaction between the monomethyhydrazine fuel and the dinitrogen tetroxide oxidizer to understand a fundamental basis of their characteristics to prepare for domestic development in future.
Structural Design and Analysis of Measurement Sensor of Automotive Exhaust System
Kim, Sangkee ; Lee, Sunhee ; Park, Hyunbum ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 82~85
DOI : 10.20910/JASE.2016.10.1.82
In this study, structural design of exhaust gas sensor of automobile was performed. In order to evaluate the structural design of the measurement sensor, the structural analysis was performed by the finite element method. The vibration and thermal stress analysis was carried out at the high temperature condition. Finally, the structural test of sensor system was performed, and used for comparison with the analyzed model. Through the structural analysis and test, it is confirmed that the designed measurement sensor structure is acceptable.
Control of Focal Plane Compensation Device for Image Stabilization of Small Satellite Camera
Kang, Myoungsoo ; Hwang, Jaihyuk ; Bae, Jaesung ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 86~94
DOI : 10.20910/JASE.2016.10.1.86
In this paper, position control of focal plane compensation device using piezoelectric actuator is conducted. The forcal plane compensation device installed on earth observation satellite camera compensates micro-vibration from reaction wheels. In this study, four experimental models of the open-loop compensation device are derived using MATLAB system identification toolbox in the input range of 0~50Hz. Subsequently, the PID controller for each model is designed and the performance test of each controller is conducted through MATLAB/Simulink. According to frequency response analysis of the closed-loop compensation device system, the PID controller designed for 38~50Hz input range has enough tracking performance for the whole 0~50Hz input range. The maximum output error is about
for the input range. The simulation results has been verified by the experimental method.
Experimental Study on Effects of Speed Error Disturbance on Reaction Wheel Control
Kim, Jichul ; Lee, Hyungjun ; Yoo, Jihoon ; Oh, Hwasuk ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 95~102
DOI : 10.20910/JASE.2016.10.1.95
There are many possible disturbance sources on such a spacecraft, but reaction wheel assembly (RWA) which is generally used for spacecraft attitude control is anticipated to be the largest. These effects on degradation of performance of spacecraft such as attitude stability. In reaction wheel, disturbance caused by imbalance and speed error. It is hard to emulate speed error disturbance because it is not coincide with wheel frequency. This paper concentrates on emulating and analyzing the speed error disturbance. Firstly, classify the causes that lead to speed error disturbance which generate RPM fluctuation. Secondly, simulated with disturbance driver module and reaction wheel assembly which are developed by Spacecraft Control Lab. Experimental investigations have been carried out to test the disturbance emulator module as a disturbance generator for RWA. Measurements and test have been conducted on various fault. Frequency analysis of test data show that speed error disturbance effects on wheel settling wheel speed or fluctuation type.
Statistical Characteristics of Domestic Composite Material Prepregs
Kim, Jinwon ; Lee, Hosung ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 103~110
DOI : 10.20910/JASE.2016.10.1.103
This study shows the statistical properties of the domestic composite material prepregs test result. During the last three years(2012.5~2015.6) the prepreg specimen tests have been performed by referring to NCAMP developed test procedure which was approved by FAA. The database of (1) Carbon Tape, (2) Glass Fabric, and (3) Carbon Fabric composite material prepregs' characteristics have been established for certified aircraft structures. This qualified materials can be used for aircraft structural design through proper material equivalency procedures.
Increasing Endurance Performance of Tiltrotor UAV Using Extended Wing
Lee, Myeong Kyu ; Lee, Chi-Hoon ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 111~117
DOI : 10.20910/JASE.2016.10.1.111
A new configuration of tiltrotor UAV previously suggested by Korea Aerospace Research Institute (KARI) for the purpose of increasing the endurance performance in airplane mode flight has extended wings attached to the nacelle and rotated with the nacelle according to the flight modes. In this research, the effectiveness of the extended wing on the enhancement of the endurance performance of KARI tiltrotor UAV (TR60) was analytically investigated based on CFD analysis results. Flight tests and ground tests of measuring the fuel consumption were also conducted to directly compare the endurance performance for the two configurations of TR60 baseline and TR60 extended-wing model.
A Study on the Mission Effect of a Sea-based BMD system
Lee, Kyoung Haing ; Choi, Jeong Hwan ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 118~126
DOI : 10.20910/JASE.2016.10.1.118
North Korea has continued developing ballistic missiles with various ranges. Even through the recent launch long-range missiles, it can be inferred that North Korea's Missile technology has reached a level where it can even threaten the US. moreover, through the three times nuclear tests, North Korea is known to have succeeded at gaining 10~20KT of explosive power as well as the minimization and lightening of nuclear warhead. Considering the short length of war zone in Korean peninsula and the possibility of nuclear equipment, if be the most severe threat across the whole peninsula. Since the midcourse phase flight takes the longest time, ROK should establish the ability to intercept at this middle phase. From this perspective, this paper describes mission effect of a sea-based BMD system through empirical threat and flight characteristic analysis using MIT model that was not suggested in original research.
The Development Option for Korea Air Defense Identification Zone(KADIZ)
Kim, Dongsoo ; Hong, Sungpyo ; Chong, Mangseok ;
Journal of Aerospace System Engineering, volume 10, issue 1, 2016, Pages 127~132
DOI : 10.20910/JASE.2016.10.1.127
Recently, China & Japan have expanded their responding ADIZ(Air Defence Identification Zone) to implement each Government's maritime policy and to project their Air Power in preparation for maritime provocation & contingency, especially over the piled area where East Asia countries have claimed to have maritime jurisdiction one another. So this is to guide the Development Option for Korea Air Defence Identification Zone to cope with the maritime intentions of the neighboring countries, considering the international law for ADIZ, the maritime policy and the maritime sovereign & jurisdiction area of the Republic of Korea, etc.