• Title/Summary/Keyword: Position Prediction

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Drag Prediction of Elliptic Airfoil (타원형 에어포일의 항력 예측)

  • Kim C. W.;Park Y. M.;Kwon K. J.;Lee J. Y.
    • 한국전산유체공학회:학술대회논문집
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    • 2004.03a
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    • pp.23-26
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    • 2004
  • Drag prediction is sought for the aifoil having laminar and turbulent flow characteristics with CFD code being unable to predict transition to turbulent flow. Laminar flow simulation presents some insight to the transition position. Separate simulations with laminar and turbulent flow and their combination estimate the drag of the airfoil containing laminar and turbulent flow characteristics.

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Improvement of Position Estimation Based on the Multisensor Fusion in Underwater Unmanned Vehicles (다중센서 융합 기반 무인잠수정 위치추정 개선)

  • Lee, Kyung-Soo;Yoon, Hee-Byung
    • Journal of the Korean Institute of Intelligent Systems
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    • v.21 no.2
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    • pp.178-185
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    • 2011
  • In this paper, we propose the position estimation algorithm based on the multisensor fusion using equalization of state variables and feedback structure. First, the state variables measured from INS of main sensor with large error and DVL of assistance sensor with small error are measured before prediction phase. Next, the equalized state variables are entered to each filter and fused the enhanced state variables for prediction and update phases. Finally, the fused state variables are returned to the main sensor for improving the position estimation of UUV. For evaluation, we create the moving course of UUV by simulation and confirm the performance of position estimation by applying the proposed algorithm. The evaluation results show that the proposed algorithm is the best for position estimation and also possible for robust position estimation at the change period of moving courses.

Disturbance Observer and Error Model-based Control of Ball Screw Drives

  • Cho, Chang-Nho;Lee, Chang-Hyuk;Kim, Hong-Ju
    • Journal of the Korean Society of Industry Convergence
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    • v.22 no.4
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    • pp.435-445
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    • 2019
  • Ball screw drives are widely used in industry, and many studies have been devoted on precise, fast and robust control of ball screw drives. In this study, a novel position control algorithm for ball screw drives is proposed, which consist of a PD controller, a friction feedforward and a disturbance observer. The dynamics and the position error of such controller are analyzed to establish an error model, which can be used to predict the resulting position error of the given desired trajectory. Using the proposed error model, the desired trajectory can be modified so that the predicted position error can be compensated in a feedforward manner. The proposed algorithm does not require the model of the system for the error prediction, and thus can be easily applied to conventional control systems. The performance of the system is verified through simulations and experiments.

A study on the estimation of impact velocity of crashed vehicles in tunnel using computer simulation(PC-CRASH) (컴퓨터 시뮬레이션(PC-CRASH)을 이용한 터널 내 피추돌 차량의 충돌 속도 추정에 관한 연구)

  • Han, Chang-Pyoung;Choi, Hong-Ju
    • Design & Manufacturing
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    • v.14 no.4
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    • pp.40-45
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    • 2020
  • In a vehicle-to-vehicle accident, the impact posture, braking status, final stopping position, collision point and collision speed are important factors for accident reconstruction. In particular, the speed of collision is the most important issue. In this study, the collision speed and the final stopping position in the tunnel were estimated using PC-CRASH, a vehicle crash analysis program used for traffic accident analysis, and the final stopping position of the simulation and the final stopping position of the traffic accident report were compared. When the Pride speed was 0km/h or 30km/h and the Sorento speed was 100m/h, the simulation results and reports matched the final stopping positions and posture of the two vehicles. As a result of the simulation, it can be estimated that Pride was collided in an almost stationary state.

The Prediction of Defection for the Shape Fixability on the Stamped Lead Frame (반도체 리드프레임의 형상 동결성에 관한 연구)

  • Cho H. K.;Kim D. H.;Lee S. B.;Kim B. M.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2001.05a
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    • pp.77-80
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    • 2001
  • IC lead frame needs the precision shape for good efficiency. In the blanking process, there are many parameter effected the dimensional accuracy : lead width, blanking order, striper force, tool clearance etc. In this research, the4 undesirable defects appeared in the final blanking process. so we measured the deflection of lead according to the stripper force using $PAM-STAMP_{TM}$. In the result, the deflection was decreased by increasing the stripper force properly. and we changed the blanking order on the test model. In the blanking order, deflection is good from the outer line position blanking to center line position. so we can design the precision die without tryout by the prediction of the lead deflection.

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A Study on Optimization of Fourth-Order Fading Memory Filter under the Highly Dynamic Motion of Both Own Ship and Target

  • Pan, Bao-Feng;Jeong, Tae-Gweon
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2017.11a
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    • pp.145-147
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    • 2017
  • Tracking filter plays a key role in accurate estimation and prediction of maneuvering vessel's dynamics. The third-order ${\alpha}-{\beta}-{\gamma}$ filter is one of the special cases of the general solution provided by the Kalman filter. Fading memory algorithm performs a better performance in numerous of ${\alpha}-{\beta}-{\gamma}$ filter algorithms. This study aims to optimize the fourth-order fading memory algorithm ${\alpha}-{\beta}-{\gamma}-{\eta}$ filter, which is extended form ${\alpha}-{\beta}-{\gamma}$ filter, to get much more accurate position of high dynamic target on the condition that the own ship is also high dynamic.

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The Study on the Cutting Force Prediction in the Ball-End Milling Process at the Random Cutting Area using Z-map (Z-map을 이용한 임의의 절삭영역에서의 볼 엔드밀의 절삭력 예측에 관한 연구)

  • 김규만
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.04a
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    • pp.125-129
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    • 1996
  • In this study, a method is proposed for the cutting force prediction of Ball-end milling process using Z-map is proposed. Any types of cutting area generated from previous cutting process can be expressed in z-map data. Cutting edge of a ball-end mill is divided into a set of finite cutting edges and the position of this edge is projected to the cross-section plane normal to the Z-axis. Comparing this projected position with Z-map data of cutting area and determining whether it is in the cutting region, total cutting force can be calculated by means of numerical integration. A series of experiments such as side cutting and upward/downard cutting was performet to verify the simulated cutting force.

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Motion predictive control for DPS using predicted drifted ship position based on deep learning and replay buffer

  • Lee, Daesoo;Lee, Seung Jae
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.12 no.1
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    • pp.768-783
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    • 2020
  • Typically, a Dynamic Positioning System (DPS) uses a PID feed-back system, and it often adopts a wind feed-forward system because of its easier implementation than a feed-forward system based on current or wave. But, because a ship's drifting motion is caused by wind, current, and wave drift loads, all three environmental loads should be considered. In this study, a motion predictive control for the PID feedback system of the DPS is proposed, which considers the three environmental loads by utilizing predicted drifted ship positions in the future since it contains information about the three environmental loads from the moment to the future. The prediction accuracy for the future drifted ship position is ensured by adopting deep learning algorithms and a replay buffer. Finally, it is shown that the proposed motion predictive system results in better station-keeping performance than the wind feed-forward system.

Geometry Coding of Three-dimensional Mesh Models Using a Joint Prediction (통합예측을 이용한 삼차원 메쉬의 기하정보 부호화 알고리듬)

  • 안정환;호요성
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.40 no.3
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    • pp.185-193
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    • 2003
  • The conventional parallelogram prediction uses only three previously traversed vertices in a single adjacent triangle; thus, the predicted vertex can be located at a biased position. Moreover, vortices on curved surfaces may not be predicted effectively since each parallelogram is assumed to lie on the same plane. In order to improve the prediction performance, we use all the neighboring vertices that precede the current vertex. After we order vortices using a vertex layer traversal algorithm, we estimate the current vertex position based on observations of the previously coded vertex positions in the layer traversal order. The difference between the original and the predicted vertex coordinate values is encoded by a uniform quantizer and an entropy coder. The proposed scheme demonstrates improved coding efficiency for various VRML test data.

Performance Comparison of GPS Fault Detection and Isolation via Pseudorange Prediction Model based Test Statistics

  • Yoo, Jang-Sik;Ahn, Jong-Sun;Lee, Young-Jae;Sung, Sang-Kyung
    • Journal of Electrical Engineering and Technology
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    • v.7 no.5
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    • pp.797-806
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    • 2012
  • Fault detection and isolation (FDI) algorithms provide fault monitoring methods in GPS measurement to isolate abnormal signals from the GPS satellites or the acquired signal in receiver. In order to monitor the occurred faults, FDI generates test statistics and decides the case that is beyond a designed threshold as a fault. For such problem of fault detection and isolation, this paper presents and evaluates position domain integrity monitoring methods by formulating various pseudorange prediction methods and investigating the resulting test statistics. In particular, precise measurements like carrier phase and Doppler rate are employed under the assumption of fault free carrier signal. The presented position domain algorithm contains the following process; first a common pseudorange prediction formula is defined with the proposed variations in pseudorange differential update. Next, a threshold computation is proposed with the test statistics distribution considering the elevation angle. Then, by examining the test statistics, fault detection and isolation is done for each satellite channel. To verify the performance, simulations using the presented fault detection methods are done for an ideal and real fault case, respectively.