• Title/Summary/Keyword: 랜딩기어

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Modelling of Fixed Wing UAV and Flight Control Computer Based Autopilot System Development for Integrated Simulation HILS Environment (고정익 UAV 모델링 및 비행조종컴퓨터 기반 오토파일럿 통합 시뮬레이션 HILS 환경 구축)

  • Kim, Lamsu;Lee, Dongwoo;Lee, Hohyeong;Hong, Suwoon;Bang, Hyochoong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.12
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    • pp.857-866
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    • 2022
  • Fixed-wing UAVs have long endurance and range capabilities compared to other aerial platforms. These advantages led fixed-wing UAVs to become a popular platform for reconnaissance missions in the military. In this research, we modeled fixed-wing UAVs, including the landing gear model and developed a guidance and control system for flight control computers to construct a HILS environment. We also developed an autopilot system that includes automated take-off, cruise, and landing control for UAVs. We also retrived the Aerodynamic coefficients an UAV using Datcom and AVL software and used them for 6 degrees of freedom modeling. The Flight control computer calculates guidance commands using the Carrot chasing guidance law after distinguishing the condition of the UAV based on 16 pre-defined flight modes and calculates control inputs using Nonlinear Dynamic Inversion (NDI) control scheme. We used RTNngine to integrate the Simulink model and flight control computer for HILS environment formulation.

Development and Application of Drop Impact Tester for Aerospace Structures (항공우주구조물 낙하충격시험기 개발 및 응용)

  • Yesol Shin;Hyejin Kim;Juho Lee
    • Journal of Aerospace System Engineering
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    • v.18 no.3
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    • pp.56-64
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    • 2024
  • In this study, a drop impact tester was developed to comprehensively conduct basic testing and academic research on the drop impact characteristics of aerospace structures. A drop tester enables accurate assessment of the dynamic stresses and deformations that occur when an aircraft collides with the ground, thereby enabling the verification of important design factors, such as safety and mechanical strength. The drop tester consists of an electromagnet to attach and drop the test object, a crane to adjust the drop height of the test object, and a drop support structure for vertical drops. Numerical analysis of the drop test object for the test was performed, and basic tests were performed using the drop impact tester. Through the analysis and test results, the structural shape of the landing gear was analyzed, and the behavior of each part was evaluated.

A Study on the Behavior of Skid Gear During the Helicopter Autorotation (헬리콥터 오토로테이션시 착륙장치 거동에 관한 연구)

  • Choi, Hyung-Tai;Oh, Jung-Jin;Kim, Geun-Won;Shin, Ki-Su
    • Journal of the Korea Institute of Military Science and Technology
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    • v.15 no.6
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    • pp.746-753
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    • 2012
  • ROK military helicopters are frequently exposed to the hazard situations due to the characteristic of operation. Especially, helicopter accident may lead to critical damage of human and structure. Accordingly, pilots have to train the autorotation procedures and learn the skill to prevent hard landing. In this paper, the behavior of skid gear subject to the helicopter autorotation was conducted by using numerical method. The computer simulation approach by using finite element method was employed to accomplish this goal. Additionally, the behavior of skid gear was evaluated for the different landing conditions. In conclusion, the maximum stress concentration was occurred at the attached area of skid cross-tube to the fuselage. Also, it was revealed that the most proper attitude was level landing to prevent hard landing.

A Numerical Study on Aerodynamic Noise Characteristics of the Tandem Cylinders using DES and FW-H Acoustic Analogy (DES와 FW-H 음향상사법을 이용한 탠덤 실린더의 공력소음 특성 연구)

  • Kim, Manshik;Lee, Youn Kyu
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.11
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    • pp.883-891
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    • 2018
  • In this paper, aerodynamic noise simulation was conducted using DES (Detached Eddy Simulation) and FW-H (Ffowcs Williams and Hawkings) acoustic analogy for the tandem cylinders which have configuration similar to a landing gear of airplanes. Numerical simulation for the tandem cylinders whose centers are 3.7D apart was carried out and results were compared with the measured data such as flow characteristics, pressure coefficients on the cylinder surfaces and far-field noise characteristics. It was confirmed that periodically shedded vortices released at the upstream cylinder and impinged on the downstream cylinder surface are major sources of aerodynamic noise. After verifying the computational method of using DES and FW-H acoustic analogy for predicting aerodynamic noise of tandem cylinders, additional simulation was conducted to examine the effect of attaching a splitter plate at the rear of the upstream cylinder. It was confirmed that the noise level in specific frequency band decreased significantly because the splitter plate changed the vortex shedding features and reduced dipole noise source.

A Study on the Establishment of Disc Braking Force Pattern to reduce the Wear Mass of Pad (패드 마모량 감소를 위한 디스크 제동력 패턴 설정에 관한 연구)

  • Kim, Seog-Won;Kim, Young-Guk;Kim, Ki-Hwan
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.786-791
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    • 2007
  • Korean high speed train(HSR-350x) has adopted a combined electrical and mechanical(friction) braking system. Brake blending control unit(BBCU) controls each brake system to fulfill the required brake performances such as braking distance, deceleration and jerk. Also the braking system should be designed considering the economical management, such as effective use of generated braking energy and the minimum wear of friction materials(a pad and a brake shoe). In this paper, we establish the disc braking force pattern that reduces the wear of pad in the disc braking system by minimizing the variance of the instantaneous disk baking energy during braking time, and compare the wear mass of pad between the conventional disc braking force pattern and the established results.

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