• Title/Summary/Keyword: Multi-rotor System

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Analysis of Stator-Rotor Interactions by using Parallel Computer (정익-동익 상호작용의 병렬처리해석)

  • Lee J. J.;Choi J. M.;Lee D. H.
    • 한국전산유체공학회:학술대회논문집
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    • 2004.10a
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    • pp.111-114
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    • 2004
  • CFD code that simulates stator-rotor interactions is developed applying parallel computing method. Modified Multi-Block Grid System which enhances perpendicularity in grid and is appropriate in parallel processing is introduced and Patched Algorithm is applied in sliding interface which is caused by movement of rotor. The experimental model in the turbo-machine is composed of 11 stators and 14 rotors. Analyses on two test cases which are one stator - one rotor model and three stators - four rotors model are performed. The results of the two cases have been compared with the experimental test data.

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Bearing Load Distribution Studies in a Multi Bearing Rotor System and a Remote Computing Method Based on the Internet

  • Yang, Zhao-Jian;Peng, Ze-Jun;Kim, Seock-Sam
    • Journal of Mechanical Science and Technology
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    • v.18 no.6
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    • pp.946-954
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    • 2004
  • A model in the form of a Bearing Load Distribution (BLD) matrix in the Multi Bearing Rotor System (MBRS) is established by a transfer matrix equation with the consideration of a bearing load, elevation and uniform load distribution. The concept of Bearing Load Sensitivity (BLS) is proposed and matrices for load and elevation sensitivity are obtained. In order to share MBRS design resources on the Internet with remote customers, the basic principle of Remote Computing (RC) based on the Internet is introduced ; the RC of the BLD and BLS is achieved by Microsoft Active Server Pages (ASP) technology.

Multiple Sliding Surface Control Approach to Twin Rotor MIMO Systems

  • Van, Quan Nguyen;Hyun, Chang-Ho
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.14 no.3
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    • pp.171-180
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    • 2014
  • In this paper, a multiple sliding surface (MSS) controller for a twin rotor multi-input-multioutput system (TRMS) with mismatched model uncertainties is proposed. The nonlinear terms in the model are regarded as model uncertainties, which do not satisfy the standard matching condition, and an MSS control technique is adopted to overcome them. In order to control the position of the TRMS, the system dynamics are pseudo-decomposed into horizontal and vertical subsystems, and two MSSs are separately designed for each subsystem. The stability of the TRMS with the proposed controller is guaranteed by the Lyapunov stability theory. Some simulation results are given to verify the proposed scheme, and the real time performances of the TRMS with the MSS controller show the effectiveness of the proposed controller.

Modeling for Twin Rotor System Using CLID (폐로식별기법에 의한 TRMS 모델링)

  • Lee, Jung-Kyung;Kwon, Oh-Kyu
    • Proceedings of the KIEE Conference
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    • 2004.11c
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    • pp.644-646
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    • 2004
  • The closed loop identification(CLID) is a very useful method for on-line applications since it can identify the plant in the closed-loop system composed of the plant and the controller. There are some literatures on CLID, but they and mainly focused on SISO(Single-Input/Single-Output) problem. In this paper, a CLID method is proposed for MIMO(Multi-Input/Multi-Output) systems. The CLID method is applied to a MIMO benchmark plant, TRMS(Twin-Rotor MIMO System). To illustrate the performance of the closed-loop system identification., unit step responses in the TRMS are represented and compared with the open-loop identification via some simulation.

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Real-Time Flight Testing for Developing an Autonomous Indoor Navigation System for a Multi-Rotor Flying Vehicle (실내 자율비행 멀티로터 비행체를 위한 실시간 비행시험 연구)

  • Kim, Hyeon;Lee, Deok Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.4
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    • pp.343-352
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    • 2016
  • A multi-rotor vehicle is an unmanned vehicle consisting of multiple rotors. A multi-rotor vehicle can be categorized as tri-, quad-, hexa-, and octo-rotor depending on the number of the rotors. Multi-rotor vehicles have many advantages due to their agile flight capabilities such as the ability for vertical take-off, landing and hovering. Thus, they can be widely used for various applications including surveillance and monitoring in urban areas. Since multi-rotors are subject to uncertain environments and disturbances, it is required to implement robust attitude stabilization and flight control techniques to compensate for this uncertainty. In this research, an advanced nonlinear control algorithm, i.e. sliding mode control, was implemented. Flight experiments were carried out using an onboard flight control computer and various real-time autonomous attitude adjustments. The feasibility and robustness for flying in uncertain environments were also verified through real-time tests based on disturbances to the multi-rotor vehicle.

Nonlinear Vibration Model of Ball Bearing Waviness in a Rigid Rotor Supported by Multi-Row Ball Bearing Considering Five Degrees of Freedom (다수의 각접촉 볼베어링으로 지지된 5자유도 회전계에서 볼베어링의 Waviness에 의해 발생하는 비선형진동 해석모델)

  • 정성원;장건희
    • Journal of KSNVE
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    • v.11 no.2
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    • pp.336-345
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    • 2001
  • This research presents a nonlinear model to analyze the ball bearing nitration due to the waviness in a rigid rotor supported by multi-row ball bearings. The waviness of a ball and each races is modeled by the superposition of sinusoidal function, and the position vectors of inner and outer groove radius center are defined with respect to the mass center of the rotor in order to consider five degrees of freedom of a general rotor-bearing system. The waviness of a ball bearing is introduced to these position vectors to use the Hertzian contact theory in order to calculate the elastic deflection and nonlinear contact force resulting from the waviness while the rotor has translational and angular motion. They can be determined by solving the nonlinear equations of motion with five degrees of freedom by using the Runge-Kutta-Fehlberg algorithm. Numerical results of this research are validated with those of prior researchers. The proposed model can calculate the translational displacement as well as the angular displacement of the rotor supported by the multi-row ball bearings with waviness. It also characterizes the nitration frequencies resulting from the various kinds of waviness in rolling elements, the harmonic frequencies resulting from the nonlinear load-deflection characteristics of ball bearing. and the sideband frequencies resulting from the waviness interaction.

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Robust Fault Detection Method for Uncertain Multivariable Systems with Application to Twin Rotor MIMO System (모형헬기를 이용한 불확정 다변수 이상검출법의 응용)

  • Kim, Dae-U;Yu, Ho-Jun;Gwon, O-Gyu
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.2
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    • pp.136-144
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    • 1999
  • This paper deals with the fault detection problem in uncertain linear multivariable systems and its application. A robust fault detection method presented by Kim et a. (1998) for MIMO (Multi Input/Multi Output) systems has been adopted and applied to the twin rotor MIMO experimental setup using industrial DSP. The system identification problem is formulated for the twin rotor MIMO system and its parameters are estimated using experimental data. Based on the estimated parameters, some fault detection simulations are performed using the robust fault detection method, which shows that the preformance is satisfied.

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Rotordynamic Characteristics of High Pressure Multistage Pump (고압 다단펌프 축계 진동 특성 고찰)

  • Song, Ae Hee;Song, Jin Dae;Lim, Woo Seop;Yang, Bo Suk
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.10a
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    • pp.592-596
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    • 2012
  • This paper presents numerical analysis result of rotor-bearing system of a multi-stage high pressure pump. Especially resonance possibility, stability and damping factor are estimated for a selected commercial multi-stage high pressure pump. The result shows that it is not easy to avoid resonance of rotor-bearing system against main excitation forces which are residual unbalance force and pressure pulsation. This makes damping effect be more important.

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A test on passing through bending critical speed of Flexible Rotor supported by AFB (AFB으로 지지된 탄성회전체의 위험속도 통과시험)

  • 이영섭;염병용;김진형;김명섭
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11a
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    • pp.354-359
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    • 2001
  • A flexible rotor was smoothly passed through its bending critical speed, which is supported by AFB. Then, maximum magnitude of the rotor vibration at the middle point was 25${\mu}$m. The test rig was largely consisted of air turbine, multi-leaf type air foil bearing and flexible rotor and its bending critical speed was 32,600 rpm. And the balancing system and method for field balancing of the flexible rotor were developd successfully.

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Wake Effect on HAT Tidal Current Power Device Performance

  • Jo, Chul-Hee;Lee, Kang-Hee;Lee, Jun-Ho;Nichita, Cristian
    • International Journal of Ocean System Engineering
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    • v.1 no.3
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    • pp.144-147
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    • 2011
  • The rotor that initially converts the flow energy into rotational energy is a very important component that affects the efficiency of the entire tidal current power system. Rotor performance is determined by various design variables. Power generation is strongly dependent on the incoming flow velocity and the size of the rotor. To extract a large quantity of power, a tidal current farm is necessary with a multi-arrangement of devices in the ocean. However, the interactions between devices also contribute significantly to the total power capacity. Therefore, rotor performance, considering the interaction problems, needs to be investigated to maximize the power generation in a limited available area. The downstream rotor efficiency is affected by the wake produced from the upstream rotor. This paper introduces the performance of a downstream rotor affected by wakes from an upstream rotor, demonstrating the interference affecting various gabs between devices.