• Title/Summary/Keyword: Thrust Control

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Experimental and Computational Studies of the Fluidic Thrust Vector Control Using a Counterflow Concept (Counterflow 개념을 이용한 추력벡터 제어에 관한 실험적 및 수치해석적 연구)

  • Lim, Chae-Min;Lee, Kwon-Hee;Kim, Heuy-Dong
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1637-1642
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    • 2004
  • Experimental and computational studies were performed to investigate the effectiveness of a thrust vectoring method using a counterflow concept. A shadowgraph method was used to visualize the supersonic jet expanded from a two-dimensional convergent-divergent nozzle and deflected by a now suction. The primary nozzle pressure and suction nozzle pressure ratios are varied between 3.0 and 5.0, and between 0.2 and 1.0 respectively. The present experimental and computational results showed that, for a given primary nozzle pressure ratio, a decrease in the suction nozzle pressure ratio produced an increased thrust vector angle, and during the change processes of the suction pressure, a hysteresis effect of the thrust vectoring was found through the wall pressure distributions.

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Performance Study of Thrust Control Unit with the Various Geometric Shapes

  • Kim, Kyoung-Ryun;Park, Jong-Ho
    • International Journal of Fluid Machinery and Systems
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    • v.9 no.4
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    • pp.354-361
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    • 2016
  • This study aims to identify aerodynamic characteristics of the ramp tab, a mechanical deflector, by conducting a non-combustive experiment using compressed air and supersonic flow test equipment. With the ramp tabs installed symmetrically and asymmetrically on the outlet of the supersonic nozzle, the structure of the flow field, the thrust spoilage, the thrust deviation angle, and the lift/drag coefficients were derived and analyzed. The results show that the asymmetrically-installed ramp tabs are advantageous relative to the symmetrically-installed tabs in terms of the performance of thrust vector control, thrust deviation angle, and lift coefficient.

Design Technique for Minimizing the Crosstalk Effect in Multiaxis Thrust Measurement Stand (다축 시험대의 상호 간섭 최소화 설계기법)

  • Kim, Joung-Keun;Yoon, Il-Sun
    • Journal of the Korean Society of Propulsion Engineers
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    • v.11 no.3
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    • pp.13-19
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    • 2007
  • This paper described design method to minimize the crosstalk effect of multiaxis thrust measurement stand which can measure the thrust vector control performance of Solid Rocket Motor. This paper presents a theoretical solution for predicting the magnitude of crosstalk and calculates design sensitivity. The results indicate that the most important parameter of crosstalk is the displacement of flexure-loadcell-flexure assembly. And shape, dimension and mechanical properties of flexure and loadcell can also influence the magnitude of crosstalk.

The Vector Control Simulation of LIM (선형유도전동기의 벡터제어 모의실험)

  • Kwon, Byung-Il;Lee, Jung-Ho;Kim, Sung-Yung
    • Proceedings of the KIEE Conference
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    • 1994.07a
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    • pp.49-51
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    • 1994
  • LIM has been developed for use in the industry, transportation, OA, FA because of the merits of direct drive and simple structure. The thrust control of LIM usually has been the average thrust control. However, vector control is required to control the instantaneous thrust force for an accurate positioning and speed control. To obtain dynamic vector control characteristics, it is important to make equivalent circuits which represent exactly LIM In this paper, asymmetrical d-q equivalent circuits is built [1] and vector control characteristics is calculated by simulation using these circuits.

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Oxidizer Flow Rate Throttling for Thrust Control of Hybrid Rocket (하이브리드 로켓의 추력제어를 위한 산화제 유량제어 연구)

  • Kim, Kye-Hwan;Moon, Keun-Hwan;Kim, Jin-Kon;Moon, Hee-Jang
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.22 no.4
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    • pp.93-98
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    • 2014
  • In this study, control of oxidizer mass flow rate and verification of control system were performed for hybrid rocket thrust control application. Oxidizer flow control system consists of ball valve and stepping motor where gaseous oxygen was used for oxidizer at feeding pressure of 10, 20 and 30 bar. According to experimental results, the oxidizer mass flow rate showed a relatively linear increment as ball valve open angle increases regardless of feeding pressure. In addition, the level of the oxidizer flow rate was kept almost constant at each sequence of flow control with ball valve during the 20 seconds of operation.

A Study of Thrust Vectoring Control Using Counterflow Concept (Counterflow Concept을 이용한 추력벡터제어에 관한 연구)

  • 정성재;임채민;김희동
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.05a
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    • pp.37-40
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    • 2003
  • The thrust vector control using a fluidic counterflow concept is achieved by applying a vacuum to a slot adjacent to a primary jet which is shrouded by a suction collar. The vacuum produces a secondary reverse flowing stream near the primary. The shear layers between the two counterflowing streams mix and entrain mass from the surrounding fluid. The presence of the collar inhibits mass entrainment and the flow m the collar accelerates causing a drop in pressure on the collar. For the vacuum asymmetrically applied to one side of the nozzle, the jet will vector toward the low-pressure region. The present study is performed to investigate the effectiveness of thrust vector control using the fluidic counterflow concept. A computational work is carried out using the two-dimensional, compressible Navier-Stokes equations, with several kinds of turbulence models. The computational results are compared with the previous experimental ones. It is found that the present fluidic counterflow concept is a viable method to vector the thrust of a propulsion system.

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Preliminary Experimental Results of Thrust Control for Hybrid Rocket (하이브리드 로켓의 추력 제어 방법에 대한 예비 실험 결과)

  • Lee, Young-Woo;Lee, Min-Jae;Lee, Jong-Lyul;Jung, Sung-Chul;Kim, Hye-Hwan;Huh, Hwan-Il
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.237-240
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    • 2007
  • To control Thrust of propulsion system, we built the 50 N level PE-COx hybrid rocket, and changed the mass flow rate of COx. From the preliminary experiential results, we could see possibility of controlling thrust of the hybrid rocket by controlling mass flow rate of COx.

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Preliminary Study of Thrust Control for Hybrid Rockets (하이브리드 로켓의 추력제어 기법에 대한 기초연구)

  • Yun, Dong-Ik;Kang, Wan-Kyu;Lee, Young-Woo;Lee, Jong-Lyul;Huh, Hwan-Il
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.257-260
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    • 2008
  • In order to control thrust of propulsion system, we built the 50 Newton level PE-GOx hybrid rocket, and changed the mass flow rate of GOx. From the preliminary experiential results, we could see possibility of controlling thrust of hybrid rockets by controlling mass flow rate of GOx.

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Variable Slip Frequency Control of LIM for Magnetically Levitated Train (자기부상열차 추진용 LIM의 운전 효율 향상을 위한 가변 슬립주파수 제어)

  • Park, Seung-Chan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.1
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    • pp.46-51
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    • 2018
  • Constant slip frequency control has been conventionally used in thrust control of the linear induction motor(LIM) for magnetically levitated train. However in this paper variable slip frequency control method is presented to increase LIM efficiency according to change of driving notch. Thrust, attractive force, input power to inverter, regenerative power of the LIM are analyzed by finite element method when the train runs according to the presented control method. As a result it is proved experimentally that the electrical energy to inverter is reduced than the conventional method.

Attitude Control of a Quad-rotor using CMG (CMG를 이용한 쿼드-로터의 자세제어)

  • Oh, Kyung-Hyun;Choi, Ho-Lim
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.7
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    • pp.695-700
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    • 2014
  • In this paper, we utilize the CMG's momentum bias to control the roll/pitch attitude of the Quad-rotor. While the previous control approaches have used the thrust control approach, we design and add a new momentum controller (using CMG) in order to improve the transient response over the existing methods. The focal point of this paper is the design of a controller for a Quad-rotor's attitude using CMG. This leads to other tasks such as an identification of the model's parameters and mathematical nonlinear modeling. Then, the previous thrust controller is designed based on the linearized model. Finally, the overall system with our designed controller is implemented and tested in real time to show that the Quad-rotor is kept in a good balanced position faster than the traditional thrust-only control approach.