Journal of the American Helicopter Society最新文献_第9页

Boundary Layer Transition Measured by DIT on the PSP Rotor in Forward Flight 用DIT测量PSP旋翼前飞边界层转捩

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2021-05-10 DOI: 10.4050/JAHS.66.022008

A. Gardner, A. Weiss, J. Heineck, A. Overmeyer, H. Spooner, Dr. R. K. Jain, C. Wolf, M. Raffel

引用次数: 2

Synthesis and Piloted Evaluation of Advanced Rotorcraft Response Types Using Robust Sliding Mode Control 基于鲁棒滑模控制的先进旋翼机响应类型综合与驾驶评估

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2021-05-10 DOI: 10.4050/JAHS.66.032008

Omkar Halbe, T. Mehling, M. Hajek, M. Vrdoljak

{"title":"Synthesis and Piloted Evaluation of Advanced Rotorcraft Response Types Using Robust Sliding Mode Control","authors":"Omkar Halbe, T. Mehling, M. Hajek, M. Vrdoljak","doi":"10.4050/JAHS.66.032008","DOIUrl":"https://doi.org/10.4050/JAHS.66.032008","url":null,"abstract":"Sliding mode control (SMC) is a promising technique for robust control synthesis with desirable properties. This paper describes the synthesis and piloted evaluation of advanced helicopter response types using the SMC technique. The required closed-loop response characteristics are\u0000 specified as ideal, lower order, axial transfer functions that conform to predicted level 1 handling qualities. Two-loop, full-authority, output-tracking SMC laws are then synthesized to enforce the closed-loop performance and accurately track pilot commands. Analytical proofs for SMC gain\u0000 tuning are given for the closed-loop performance to remain robust to unknown but bounded uncertainties in the input channels and the effects of rotor modes on closed-loop stability. The closed-loop eigenstructure is nearly identical to the specified closed-loop performance and has good modal\u0000 decoupling. Furthermore, a frequency domain analysis with a nonlinear helicopter model shows good stability margins and disturbance rejection characteristics. Finally, the paper reports on simulation testing conducted with four experimental test pilots in a rotorcraft simulation environment.\u0000 The simulation results indicate improved mission task performance and handling qualities ratings and a substantial reduction in pilot workload for the SMC-based advanced response types compared to the bare-airframe responses.","PeriodicalId":50017,"journal":{"name":"Journal of the American Helicopter Society","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42183669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

If you want to keep the Japanese Association of Hydrological Sciences active, you should submit “a kind of paper” to the Journal of Japanese Association of Hydrological Sciences 如果你想保持日本水文科学协会的活跃，你应该向日本水文科学协会杂志提交“一种论文”

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2021-04-25 DOI: 10.4145/JAHS.51.7

A. Higuchi

引用次数: 0

Prediction of Urban Air Mobility Multirotor VTOL Broadband Noise Using UCD-QuietFly 基于UCD-QuietFly的城市空中机动多旋翼垂直起降宽带噪声预测

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2021-01-01 DOI: 10.4050/JAHS.66.032004

Sicheng Li, Seongkyu Lee

{"title":"Prediction of Urban Air Mobility Multirotor VTOL Broadband Noise Using UCD-QuietFly","authors":"Sicheng Li, Seongkyu Lee","doi":"10.4050/JAHS.66.032004","DOIUrl":"https://doi.org/10.4050/JAHS.66.032004","url":null,"abstract":"This paper investigates broadband noise of multirotor urban air mobility (UAM) vertical take-off and landing (VTOL) vehicles. Based on an earlier single-rotor trailing-edge noise prediction method, a multirotor broadband noise prediction program is developed, where the multirotor coordinate transformation is included, and the amplitude modulation capability is introduced. Thereafter, the program is used to predict broadband noise from three UAM VTOL conceptual designs and a vertiport conceptual design. It is found that UAM VTOL vehicles' broadband noise is important in the high-frequency range, where the community background noise level is typically low. For the same mission specifications, broadband noise is found to be higher for VTOL designs with more rotors. UAM vehicle noise is compared to conventional helicopter noise. It is found that the amplitude modulation of broadband noise of a single rotor is insignificant when the observer distance is larger than four rotor radii. Multirotor vehicles at the same rotational speeds have weaker amplitude modulations than a single rotor, which demonstrates the benefits of using multiple rotors in terms of noise annoyance. Finally, noise contours from a vertiport design show an increase in the broadband noise level when multiple VTOL vehicles are operated simultaneously.","PeriodicalId":50017,"journal":{"name":"Journal of the American Helicopter Society","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70215965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 12

Impact of Tip-Vortex Modeling Uncertainty on Helicopter Rotor Blade–Vortex Interaction Noise Prediction 叶尖涡流建模不确定性对直升机旋翼桨叶-涡流相互作用噪声预测的影响

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2021-01-01 DOI: 10.4050/jahs.66.012005

Stavros Vouros, I. Goulos, C. Scullion, D. Nalianda, V. Pachidis

{"title":"Impact of Tip-Vortex Modeling Uncertainty on Helicopter Rotor Blade–Vortex Interaction Noise Prediction","authors":"Stavros Vouros, I. Goulos, C. Scullion, D. Nalianda, V. Pachidis","doi":"10.4050/jahs.66.012005","DOIUrl":"https://doi.org/10.4050/jahs.66.012005","url":null,"abstract":"Free-wake models are routinely used in aeroacoustic analysis of helicopter rotors; however, their semiempiricism is accompanied with uncertainty related to the modeling of physical wake parameters. In some cases, analysts have to resort to empirical adaption of these parameters based\u0000 on previous experimental evidence. This paper investigates the impact of inherent uncertainty in wake aerodynamic modeling on the robustness of helicopter rotor aeroacoustic analysis. A free-wake aeroelastic rotor model is employed to predict high-resolution unsteady airloads, including blade–vortex\u0000 interactions. A rotor aeroacoustics model, based on integral solutions of the Ffowcs Williams–Hawkings equation, is utilized to calculate aerodynamic noise in the time domain. The individual analytical models are incorporated into an uncertainty analysis numerical procedure, implemented\u0000 through nonintrusive Polynomial Chaos expansion. The potential sources of uncertainty in wake tip-vortex core growth modeling are identified and their impact on noise predictions is systematically quantified. When experimental data to adjust the tip-vortex core model are not available the\u0000 uncertainty in acoustic pressure and noise impact at observers dominated by blade–vortex interaction noise can reach up to 25% and 3.50 dB, respectively. A set of generalized uncertainty maps is derived, for use as modeling guidelines for aeroacoustic analysis in the absence of the robust\u0000 evidence necessary for calibration of semiempirical vortex core models.","PeriodicalId":50017,"journal":{"name":"Journal of the American Helicopter Society","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48943503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Small UAS and Delivery Drones: Challenges and Opportunities The 38th Alexander A. Nikolsky Honorary Lecture 第38届亚历山大·a·尼古拉基荣誉讲座

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2021-01-01 DOI: 10.4050/jahs.66.042001

I. Chopra

引用次数: 1

Analytic Model of Proprotor Forces and Moments at High Incidence 高入射角角力和力矩的解析模型

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2021-01-01 DOI: 10.4050/jahs.66.042002

Yuchen Leng, T. Jardin, J. Moschetta, M. Bronz

{"title":"Analytic Model of Proprotor Forces and Moments at High Incidence","authors":"Yuchen Leng, T. Jardin, J. Moschetta, M. Bronz","doi":"10.4050/jahs.66.042002","DOIUrl":"https://doi.org/10.4050/jahs.66.042002","url":null,"abstract":"The paper presents an analytical model for estimation of proprotor aerodynamic loads at elevated incidence angles. Previous theories have concentrated on either small incidence angle for aircraft stability analysis or edge-wise flow for helicopter forward flight. This development attempted an engineering method that covers the full incidence angle range from 0 to π/2. Blade element theory was applied to known proprotor geometry, and off-axis loads including normal force and in-plane moment were obtained in closed form based on thrust and torque in axial condition. The model was found to be sufficiently accurate over a broader flight conditions compared to classical models, and computationally more efficient than numerical methods. Hence it could be easily used as a preliminary design and analysis tool for future convertible aircraft proprotors. The paper further discusses a dedicated wind tunnel campaign on proprotor off-axis load measurement. Experimental data from the test campaign was considered in model validation. The results suggested that the model was capable to accurately estimate proprotor performance in nominal flight regimes.","PeriodicalId":50017,"journal":{"name":"Journal of the American Helicopter Society","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70215930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Normalized Adaptive Hybrid Control Algorithms for Helicopter Vibration with Variable Rotor Speed 直升机变旋翼速度振动归一化自适应混合控制算法

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2021-01-01 DOI: 10.4050/jahs.67.022008

K. Lang, P. Xia, E. Smith, L. Shang

{"title":"Normalized Adaptive Hybrid Control Algorithms for Helicopter Vibration with Variable Rotor Speed","authors":"K. Lang, P. Xia, E. Smith, L. Shang","doi":"10.4050/jahs.67.022008","DOIUrl":"https://doi.org/10.4050/jahs.67.022008","url":null,"abstract":"Variable rotor speed technology implemented in a helicopter can improve the flight performance, reduce the required power, and increase the flight speed. However, variable rotor speed changes the frequencies of rotor vibratory loads and may produce helicopter fuselage resonance under the excitation of the rotor vibratory loads. Active vibration control (AVC) has been effectively used in vibration reduction of helicopter fuselages. However, the frequency domain control algorithms that are currently used have poor adaptability in controlling vibration with variable frequencies (i.e., during time varying rotor speeds). In order to effectively improve control convergence, adaptability, and effectiveness, the normalized adaptive hybrid control algorithms containing both the normalized adaptive harmonic control algorithm and the normalized frequency tracking algorithm have been presented in this paper. Simulations of AVC with variable frequencies on a dynamically similar frame structure of a helicopter fuselage driven by piezoelectric stack actuators installed on the gearbox support struts show that the normalized adaptive hybrid control algorithms can accurately track the changes in rotor load frequencies and can be effectively used in the AVC of a helicopter with variable rotor speed.","PeriodicalId":50017,"journal":{"name":"Journal of the American Helicopter Society","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70217092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

How Big Is a Lock Number? 锁号有多大?

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2021-01-01 DOI: 10.4050/jahs.66.012001

Cory Seidel, D. Peters

引用次数: 0

Higher Harmonic Control: A Historical Perspective 高谐波控制:一个历史的视角

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2021-01-01 DOI: 10.4050/JAHS.66.022001

C. Hammond, Lockheed Martin

{"title":"Higher Harmonic Control: A Historical Perspective","authors":"C. Hammond, Lockheed Martin","doi":"10.4050/JAHS.66.022001","DOIUrl":"https://doi.org/10.4050/JAHS.66.022001","url":null,"abstract":"Higher harmonic control (HHC) is an approach for achieving reduced helicopter vibration by controlling the vibratory rotor airloads in such a way that the fuselage excitation is minimized. This paper is a historical look at how a program aimed at helicopter vibration reduction started as an outgrowth of fixed wing flutter suppression at NASA Langley Research Center, proved the HHC concept on aeroelastically scaled wind tunnel models and went on to demonstrate viability in full-scale flight testing on the OH-6A helicopter in 1982. Following the OH-6A flight tests, the helicopter research community was stimulated to prove the effectiveness of HHC on different configurations through analysis, wind tunnel tests, and flight tests. All of these investigations have shown HHC to be effective in reducing vibration to levels not attainable with conventional vibration control methods and without any detrimental side effects. HHC development has progressed to the point that the technology provides one more option to address the ever-present vibration problem in helicopters. The literature demonstrates that helicopter ride quality equivalent to that of fixed wing aircraft is attainable with application of HHC.","PeriodicalId":50017,"journal":{"name":"Journal of the American Helicopter Society","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70215159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2