• Title, Summary, Keyword: Dynamic trim algorithm

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Design of a Flight Envelope Protection System Using a Dynamic Trim Algorithm

  • Shin, Ho-Hyun;Lee, Sang-Hyun;Kim, You-Dan;Kim, Eung-Tae;Sung, Ki-Jung
    • International Journal of Aeronautical and Space Sciences
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    • v.12 no.3
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    • pp.241-251
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    • 2011
  • Most large commercial aircrafts and high performance military aircrafts use fly-by-wire (FBW) or fly-by-light systems to improve their controllability, comfort, and safety. A flight envelope protection technique is used with flight control systems utilizing the FBW technique. Such flight envelope protection systems prevent these aircraft from exceeding the structural/aerodynamic limits and control their surface limits. This is accomplished by predicting the values of the future state variables and adaptively compensating the control action. In this study, the conventional dynamic trim algorithm of the flight envelope protection is modified to increase the method accuracy and to handle cases with multiple variables. Numerical simulation is also performed to verify the performance of the proposed method.

Helicopter Trim Analysis and Flight Simulation by Uising DAE Based PPTA (Partial Periodic Trimming Algorithm) (DAE 해법과 PPTA(Partial Periodic Trimming Algorithm)를 이용한 헬리콥터 트림해석 및 비행 시뮬레이션)

  • Kim,Chang-Ju
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.1
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    • pp.42-48
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    • 2003
  • To get a periodic trim solution from Level II helicopter flight dynamic equations, DAE based PPT A (partial Periodic Trimming Algorithm) has been proposed. Iterative update of state variables from PPT A can cause a numerical instability in DAE solver which needs compatible initial conditions. By simply adjusting the order of DAE solver a periodic trim can be obtained with good accuracy. Application for CBM (Common Baseline Model) helicopter showed the same trim result as harmonic balance method and the effective elimination of unrealistic initial responses at the start of flight simulation.

Design of Pitch Limit Detection Algorithm for Submarine (잠수함의 종동요각 한계예측 알고리즘 설계)

  • Park, Jong-Yong;Kim, Nakwan;Shin, Yong-Ku
    • Journal of Ocean Engineering and Technology
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    • v.30 no.2
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    • pp.134-140
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    • 2016
  • An envelope protection system is a control system that allows a submarine to operate freely using its own operational envelope without exceeding the structural limit, dynamic limit, and control input limit. In this paper, an envelope protection system for the pitch angle of a submarine is designed using a dynamic trim algorithm. A linear quadratic regulator and artificial neural network are used for the true dynamics approximation. A submarine maneuvering simulation program developed using experimental data is used to validate the designed envelope protection system. Simulation results show the effectiveness of the designed envelope protection system.

Design of Flight Envelope Protection System on Velocity of Aircraft (항공기의 수평속도에 대한 비행영역 보호 시스템 설계)

  • Shin, Ho-Hyun;Lee, Sang-Hyun;Kim, You-Dan;Kim, Eung-Tae;Seong, Ki-Jung;Choi, Hyoung-Sik
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.4
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    • pp.327-334
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    • 2010
  • Recently developed aircrafts use Fly-By-Wire(FBW) or Fly-By-Light(FBL) system. These systems have some merits; they can perform very complicated missions, they can expand the flight region and improve the reliability of the aircrafts. With the development of flight control systems that use FBW technique, flight envelope protection concept is introduced to guarantee reliability of the aircraft and improve the efficiency of mission achievement. In this study, flight envelope protection system is designed using a dynamic trim algorithm, a peak response estimation, and a gain scheduling technique. The performance of these methods are compared by performing numerical simulation.

System Identification and Pitch Control of a Planing Hull Ship with a Controllable Stern Intercepter (능동제어가 가능한 선미 인터셉터가 부착된 활주선형 선박의 시스템 식별과 자세 제어에 관한 연구)

  • Choi, Hujae;Park, Jongyong;Kim, Dongjin;Kim, Sunyoung;Lee, Jooho;Ahn, Jinhyeong;Kim, Nakwan
    • Journal of the Society of Naval Architects of Korea
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    • v.55 no.5
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    • pp.401-414
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    • 2018
  • Planing hull type ships are often equipped with interceptor or trim tab to improve the excessive trim angle which leads to poor resistance and sea keeping performances. The purpose of this study is to design a controller to control the attitude of the ship by controllable stern interceptor and validate the effectiveness of the attitude control by the towing tank test. Embedded controller, servo motor and controllable stern interceptor system were equipped with planing hull type model ship. Prior to designing the control algorithm, a model test was performed to identify the system dynamic model of the planing hull type ship including the stern interceptor. The matrix components of model were optimized by Genetic Algorithm. Using the identified model, PID controller which is a classical controller and sliding mode controller which is a nonlinear robust controller were designed. Gain tuning of the controllers and running simulation was conducted before the towing tank test. Inserting the designed control algorithm into the embedded controller of the model ship, the effectiveness of the active control of the stern interceptor was validated by towing tank test. In still water test with small disturbance, the sliding mode controller showed better performance of canceling the disturbance and the steady-state control performance than the PID controller.