• Title/Summary/Keyword: 다중 로터 시스템

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Study on Performance Analyses on Coaxial Co-rotating Rotors of e-VTOL Aircraft for Urban Air Mobility (도심 항공 교통을 위한 전기동력 수직 이착륙기의 동축 동회전 로터의 성능해석 연구)

  • Lee, Yu-Been;Park, Jae-Sang
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.49 no.12
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    • pp.1011-1018
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    • 2021
  • This numerical study conducts the modeling and the hover performance analyses of coaxial co-rotating rotor(or stacked rotor), using a rotorcraft comprehensive analysis code, CAMRAD II. The important design parameters such as the index angle and axial spacing for the coaxial co-rotating rotor are varied in this simulation study. The coaxial co-rotating rotor is trimmed using the torque value of the upper rotor of the previous coaxial counter-rotating rotor or the total thrust value of the previous coaxial counter-rotating rotor in hover. The maximum increases in the rotor thrust is 1.84% for the index angle of -10° when using the torque trim approach. In addition, the maximum decreases in the rotor power is 4.53% for the index angle of 20° with the thrust trim method. Thus, the present study shows that the hover performance of the coaxial co-rotating rotor for e-VTOL aircraft can be changed by the index angle.

Active Fault Tolerant Control of Quadrotor Based on Multiple Sliding Surface Control Method (다중 슬라이딩 표면 제어 기법에 기반한 쿼드로터의 능동 결함 허용 제어)

  • Hwang, Nam-Eung;Kim, Byung-Soo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.17 no.1
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    • pp.59-70
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    • 2022
  • In this paper, we proposed an active fault tolerant control (AFTC) method for the position control of a quadrotor with complete loss of effectiveness of one motor. We obtained the dynamics of a quadrotor using Lagrangian equation without small angle assumption. For detecting the fault on a motor, we designed a fault detection module, which consists of the fault detection and diagnosis (FDD) module and the fault detection and isolation (FDI) module. For the FDD module, we designed a nonlinear observer that observes the states of a quadrotor based on the obtained dynamics. Using the observed states of a quadrotor, we designed residual signals and set the appropriate threshold values of residual signals to detect the fault. Also, we designed an FDI module to identify the fault location using the designed additional conditions. To make a quadrotor track the desired path after detecting the fault of a motor, we designed a fault tolerant controller based on the multiple sliding surface control (MSSC) technique. Finally, through simulations, we verified the effectiveness of the proposed AFTC method for a quadrotor with complete loss of effectiveness of one motor.

A Test Bench with Six Degrees of Freedom of Motion For Development of Small Quadrotor Drones (소형 쿼드로터 드론 개발을 위한 6 자유도 운동 실험 장치)

  • Jin, Jaehyun;Jo, Jin-Hee
    • Journal of Aerospace System Engineering
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    • v.11 no.1
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    • pp.41-46
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    • 2017
  • A new test bench for small multi-rotor type drones has been developed. Six degrees of freedom (DOF) motion is possible due to a ball bushing, wheels, and rotating plates. An FPGA (field programmable gate array) based controller, that supports realtime parallel processing, is used to measure attitude with an accelerometer and a gyro to adjust motor speed. Several tests were performed to check the operational properties of the test bench and the controller. The results show that this test bench is proper for verifying controllers and the control methods of small multi-rotor drones.

Vibration Reduction Simulation of UH-60A Helicopter Airframe Using Active Vibration Control System (능동 진동 제어 시스템을 이용한 UH-60A 헬리콥터 기체의 진동 감소 시뮬레이션)

  • Lee, Ye-Lin;Kim, Do-Young;Kim, Do-Hyung;Hong, Sung-Boo;Park, Jae-Sang
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.6
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    • pp.443-453
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    • 2020
  • This study using the active vibration control technique attempts to alleviate numerically the airframe vibration of a UH-60A helicopter. The AVCS(Active Vibration Control System) is applied to reduce the 4/rev vibration responses at the specified locations of the UH-60A airframe. The 4/rev hub vibratory loads of the UH-60A rotor is predicted using the nonlinear flexible dynamics analysis code, DYMORE II. Various tools such as NDARC, MSC.NASTRAN, and MATLAB Simulink are used for the AVCS simulation with five CRFGs and seven accelerometers. At a flight speed of 158knots, the predicted 4/rev hub vibratory loads of UH-60A rotor excite the airframe, and then the 4/rev vibration responses at the specified airframe positions such as the pilot seat, rotor-fuselage joint, mid-cabin, and aft-cabin are calculated without and with AVCS. The 4/rev vibration responses at all the locations and directions are reduced by from 25.14 to 96.05% when AVCS is used, as compared to the baseline results without AVCS.

Design of Multiple Sliding Surface Control System for a Quadrotor Equipped with a Manipulator (매니퓰레이터 장착 쿼드로터를 위한 다중 슬라이딩 평면 제어의 시스템 설계)

  • Hwang, Nam Eung;Park, Jin Bae;Choi, Yoon Ho
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.7
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    • pp.502-507
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    • 2016
  • In this paper, we propose a tracking control method for a quadrotor equipped with a 2-DOF manipulator, which is based on the multiple sliding surface control (MSSC) method. To derive the model of a quadrotor equipped with a 2-DOF manipulator, we obtain the models of a quadrotor and a 2-DOF manipulator based on the Lagrange-Euler formulation separately - and include the inertia and the reactive torque generated by a manipulator when these obtained models are combined. To make a quadrotor equipped with a manipulator track the desired path, we design a double-loop controller. The desired position is converted into the desired angular position in the outer controller and the system's angle tracks the desired angular position through the inner controller based on the MSSC method. We prove that the position-tracking error asymptotically converges to zero based on the Lyapunov stability theory. Finally, we demonstrate the effectiveness of the proposed control system through a computer simulation.

Numerical Study on the Effect of the Arrangement Type of Rotor Sail on Lift Formation (로터세일의 배열 형태가 양력 형성에 미치는 영향에 관한 수치해석적 연구)

  • Jung-Eun Kim;Dae-Hwan Cho;Chang-Yong Lee
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.29 no.2
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    • pp.197-206
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    • 2023
  • Recently, the international community, including the International Maritime Organization (IMO), has strengthened regulations on air pollution emissions of ships, and eco-friendly ships are actively being developed to reduce exhaust gas emissions. Among them, rotor sail (RS), a wind-assisted ship propulsion system, is attracting attention again. RS is a cylindrical device installed on the ship deck, that generates hydrodynamic lift using a magnus effect. This is a next generation eco-friendly auxiliary propulsion technology, and Enercon company, which developed RS-applied ships, announced that fuel savings of more than 30% are possible. In this study, optimal installation conditions such as RS spacing and arrangement type were selected when multiple RSs were installed on ships. AR=5.1, SR=1.0, and De/D was fixed at 2.0 according to the RS arrangement, and the wind direction was considered only for the unidirectional +y-axis. Regarding arrangement conditions, five conditions were set at 3D intervals in the +x-axis direction from 3D to 15D and five conditions in the +y-axis direction from 5D to 25D. CL, CD and aerodynamic efficiency (CL/CD) were compared according to the square(□) and diamond(◇) shape arrangements. Consequently, the effect of RS on the longitudinal distance was not significantly different. However, in the case of RS flow characteristics according to the transverse distance, the interaction effect of RS was the greatest when the two RSs almost matched the wind direction. In the case of the RS flow characteristics according to the arrangement, notably, when the wind blew in the forward (0°) direction, the diamond (◇) arrangement was least affected by the backward flow between RSs.

Dynamic Stability Analysis of Wind Turbines Considering Periodic Blade Pitch Actions (블레이드의 주기적 피치운동을 고려한 풍력 터빈의 동적 안정성 해석)

  • Kim, Kyungtaek;Lee, Chongwon
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.186-186
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    • 2010
  • 개별 블레이드 피치 제어(individual blade pitch control)는 각각의 로터 블레이드의 피치각을 독립적으로 조정함으로써 블레이드에 작용하는 공력을 변화시키는 원리로 풍력 터빈 구조물에 발생하는 동적 피로하중을 저감시키기 위한 제어기법이다. 그러나 개별 피치 제어에 의해 발생하는 각 블레이드의 독립적인 피치 운동은 풍력 터빈 회전자에 비대칭성을 야기하고 구조물의 동적 불안정 현상을 발생시킬 수 있기 때문에 이에 대한 정확한 동적 해석이 선행되어야 한다. 하지만 블레이드의 피치 운동이 반영된 풍력 터빈은 시변계로 간주되어 기존의 시불변계 해석기법을 직접 적용할 수 없기 때문에 동적 해석에 어려움이 있다. 이 논문에서는 각각의 블레이드 피치운동을 주기함수로 근사화 함으로써 풍력 터빈을 주기 시변계로 모형화한다. 그리고 효율적으로 주기 시변계의 근사해를 구하기 위한 변조 좌표 변환(modulated coordinate transformation)기법을 적용하여 블레이드의 피치운동이 반영된 풍력 터빈의 동적 안정성 해석을 수행하였다. 그리고 현재 풍력 터빈의 동적 해석에 활용되는 대표적인 해석 기법인 다중 블레이드 좌표변환(multi-blade coordinate transformation)기법을 이용한 해석보다 정확한 결과를 얻을 수 있음을 보였다.

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