• Title/Summary/Keyword: Multi-rotor System

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Performance Analysis and Pitch Control of Dual-Rotor Wind Turbine Generator System (Dual-Rotor 풍력 발전 시스템 성능 해석 및 피치 제어에 관한 연구)

  • Cho, Yun-Mo;No, Tae-Soo;Jung, Sung-Nam;Kim, Ji-Yon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.7
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    • pp.40-50
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    • 2005
  • In this paper, preliminary results for performance prediction of a dual-rotor wind turbine generator system are presented. Blade element and momentum theories are used to model the aerodynamic forces and moments acting on the rotor blades, and multi-body dynamics approach is used to integrate the major components to represent the overall system. Not only the steady-state performance but the transient response characteristics are analyzed. Pitch control strategy to control the rotor speed and the generator output is proposed and its performance is verified through the nonlinear simulation.

Numerical Analysis of Aerodynamic Performance for Tilt Rotor Aircraft in Cruise Mode Using Chimaera Grid Method (겹침격자 기법을 이용한 틸트로터의 순항모드에 대한 공력성능 수치해석)

  • Ko S. H.;Ahn S. W.;Kim B. S.
    • 한국전산유체공학회:학술대회논문집
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    • 2004.10a
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    • pp.87-90
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    • 2004
  • A numerical analysis was made for the unsteady flow fields of rotor system of a Tilt-Rotor aircraft in cruise mode. The Reynolds-averaged thin-layer Navier-Stokes equations were discretized by Roe's upwind differencing scheme and integrated in time by the LU-SGS algorithm. The computational domain of the rotor system was constructed by six multi-block Chimera grids. Simulated unsteady flow fields of rotating blades were studied in several different view points.

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Experimental Framework for Controller Design of a Rotorcraft Unmanned Aerial Vehicle Using Multi-Camera System

  • Oh, Hyon-Dong;Won, Dae-Yeon;Huh, Sung-Sik;Shim, David Hyun-Chul;Tahk, Min-Jea
    • International Journal of Aeronautical and Space Sciences
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    • v.11 no.2
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    • pp.69-79
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    • 2010
  • This paper describes the experimental framework for the control system design and validation of a rotorcraft unmanned aerial vehicle (UAV). Our approach follows the general procedure of nonlinear modeling, linear controller design, nonlinear simulation and flight test but uses an indoor-installed multi-camera system, which can provide full 6-degree of freedom (DOF) navigation information with high accuracy, to overcome the limitation of an outdoor flight experiment. In addition, a 3-DOF flying mill is used for the performance validation of the attitude control, which considers the characteristics of the multi-rotor type rotorcraft UAV. Our framework is applied to the design and mathematical modeling of the control system for a quad-rotor UAV, which was selected as the test-bed vehicle, and the controller design using the classical proportional-integral-derivative control method is explained. The experimental results showed that the proposed approach can be viewed as a successful tool in developing the controller of new rotorcraft UAVs with reduced cost and time.

Design of a Composite Flywheel Rotor for Energy Storage System (에너지 저장시스템용 복합재 플라이휠 로터의 설계)

  • 정희문;최상규;하성규
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.7
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    • pp.1665-1674
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    • 1995
  • An optimum design has been performed to maximize specific energy (SED) of composite flywheel rotor for energy storage system. The flywheel rotor is assumed to be an axisymmetric thick laminated shell with a plane strain state for structural analysis. For the structural analysis the centrifugal force is considered and the stiffness matrix equation was derived for each ring considering the interferences between the rings. The global stiffness matrix was derived by integrating the local stiffness matrix satisfying the conditions of force and displacement compatibilities. Displacements are then calculated from the global stiffness matrix and the stresses in each ring are also calculated. 3-D intra-laminar quadratic Tsai-Wu criterion is then used for the strength analysis. An optimum procedure is also developed to find the optimal interferences and lay up angle to maximize SED using the sensitivity analysis.

Robust Centralized Servocontroller Design for a Rotor System Supported by Magnetic Bearings (자기베어링 지지 로터계를 위한 견실한 중앙집중식 서보제어기 설계)

  • 김종원
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.6
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    • pp.1141-1149
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    • 1992
  • This paper presents a robust centralized control scheme for a magnetic bearing system which supports a rigid rotor at both shaft ends in the radial direction. The negative stiffness element and the inductive force associated with bearing magnetic field are considered in the dynamic model of the system. For this model, the controllability and observability are examined, and then a robust control theory is applied to design two types of multi-input multi-output servocontrollers. A general servocompensator is embedded in the first one and a centralized PID controller is suggested as a second one. By simulation study, the performance of two types of servocontrollers are compared in the aspects of disturbance rejection, reference tracking and the robustness limit.

Design and Validation of Low-cost Flight Control Computer for Multi-rotor UAVs (저가 하드웨어 기반 멀티로터 비행제어 컴퓨터 설계 및 검증)

  • Lee, Dasol;Shim, David Hyunchul
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.5
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    • pp.401-408
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    • 2017
  • This paper describes development and validation processes of a low-cost hardware based flight control computer designed for multi-rotor UAVs. The developed flight control computer controls multi-rotors stable and can handle complex flight missions using an integrated high-performance Linux computer. A complementary filter generates a navigation solution with 500 Hz, and a proposed observer significantly reduces measurement noise. A control algorithm utilizes a feed-forward term computed by a three-dimensional curve fitting method, and it increases tracking performance. The developed flight control system has been fully tested through several test flights, and it can apply to real flight environments.

An Improved Substructure Synthesis Method for Unbalance Response Analysis of Rotor Bearing Systems (회전체 베어링계의 불균형 응답 해석을 위한 개선된 부분 구조 합성법)

  • 홍성욱;박종혁
    • Journal of KSNVE
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    • v.6 no.1
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    • pp.71-82
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    • 1996
  • The finite element analysis for rotor bearing systems has been an essential tool for design, identification, and diagnosis of rotating machinery. Among others, the unbalance response analysis is fundamental in the vibration analysis of rotor bearing systems because rotating unbalance is recognized as a common sourve of vibration in rotating machinery. However there still remains a problem in the aspect of computational efficiency for unbalance response analysis of large rotor bearing systems. Gyroscopic terms and local bearing parameters in rotor bearing systems often make matters worse in unbalance response computation due to the complicated dynamic properties such as rotational speed dependency and/or anisotropy. The present paper proposes an efficient method for unbalance responses of multi-span rotor bearing systems. An improved substructure synthesis scheme is introduced which makes it possible to compute unbalance responses of the system by coupling unbalance responses of substructures that are of self adjoint problem with small order matrices. The present paper also suggests a scheme to easily deal with gyroscopic tems and local, coupling or bearing parameters. The proposed method causes no errors even though the computational effort is reduced drastically. The present method is demonstrated through three test examples.

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Performance Analysis of the Eddy Current Braker with Multi-layer Rotor Considering Constant Braking Torque

  • Kim, Cherl-Jin;Lee, Kwan-Yong;Han, Kyoung-Hee;Beak, Soo-Hyun
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.4B no.2
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    • pp.59-64
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    • 2004
  • Study of an accurate and robust braking control method is required as a technical improvement to the servo system. In particular, the braker exhibiting constant braking performance under speed variation conditions of the prime mover needs to be investigated. In this paper, the braking torque of the eddy current braker between the electromagnet stator and rotating disk is analyzed. The torque-speed characteristics and accurate disk construction are represented. From the computer simulation results, it was found that eddy current braking torque is linear or approximately constant over the desired speed range depending on the rotor material, disk construction, pole number and pole displacement of the stator. These relations are confirmed by experimental results.

Calculation of Electromagnetic Excitation Forces in Double Skewed Motors

  • Bao, Xiaohua;Di, Chong;Zhou, Yang
    • Journal of Electrical Engineering and Technology
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    • v.13 no.2
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    • pp.812-821
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    • 2018
  • An electromagnetic excitation force is caused by the air-gap flux density, which greatly influences the noise and vibration of the motor. In many real projects, skewed slot technology is widely used to reduce the harmonic components of the air-gap flux density to reduce the noise and vibration of the motor. However, a skewed slot has several side effects such as a transverse current and axial drifting. Thus, a double skewed slot rotor is selected with the aim of eliminating these side effects. This paper presents the exact structure of the double skewed slot rotor and the mechanism whereby the electromagnetic excitation force can be reduced. A multi-slice method is adopted to model the special structure. Finite element simulation is used to verify the theory.

Multi-Objective Optimum Shape Design of Rotor-Bearing System with Dynamic Constraints Using Immune-Genetic Algorithm (면역.유전 알고리듬을 이용한 로터 베어링시스템의 다목적 형상최적설계)

  • Choe, Byeong-Geun;Yang, Bo-Seok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.7 s.178
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    • pp.1661-1672
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    • 2000
  • An immune system has powerful abilities such as memory, recognition and learning how to respond to invading antigens, and has been applied to many engineering algorithms in recent year. In this pap er, the combined optimization algorithm (Immune- Genetic Algorithm: IGA) is proposed for multi-optimization problems by introducing the capability of the immune system that controls the proliferation of clones to the genetic algorithm. The optimizing ability of the proposed combined algorithm is identified by comparing the result of optimization with simple genetic algorithm for two dimensional multi-peak function which have many local optimums. Also the new combined algorithm is applied to minimize the total weight of the shaft and the transmitted forces at the bearings. The inner diameter oil the shaft and the bearing stiffness are chosen as the design variables. The dynamic characteristics are determined by applying the generalized FEM. The results show that the combined algorithm and reduce both the weight of the shaft and the transmitted forces at the bearing with dynamic conatriants.