Journal of the American Helicopter Society最新文献_第3页

Collisions between Drones and Rotorcraft: Modeling of the Crash Response of Battery Packs 无人机和旋翼飞行器之间的碰撞:电池组碰撞响应的建模

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2023-01-01 DOI: 10.4050/jahs.69.012004

M. May, N. Schneider, B. Schaufelberger, Markus Jung, Jonas Pfaff, Anja Altes, T. Haase, S. Schopferer, M. Imbert, P. Matura, Martin Blacha

引用次数: 0

Towards Flight Envelope Protection for the NASA Tiltwing eVTOL Flight Mode Transition Using Hamilton–Jacobi Reachability 利用Hamilton-Jacobi可达性实现NASA倾翼eVTOL飞行模式转换的飞行包线保护

4区工程技术

Journal of the American Helicopter Society Pub Date : 2023-01-01 DOI: 10.4050/jahs.69.022003

Ting-Wei Hsu, Jason J. Choi, Divyang Amin, Claire Tomlin, Shaun C. McWherter, Michael Piedmonte

{"title":"Towards Flight Envelope Protection for the NASA Tiltwing eVTOL Flight Mode Transition Using Hamilton–Jacobi Reachability","authors":"Ting-Wei Hsu, Jason J. Choi, Divyang Amin, Claire Tomlin, Shaun C. McWherter, Michael Piedmonte","doi":"10.4050/jahs.69.022003","DOIUrl":"https://doi.org/10.4050/jahs.69.022003","url":null,"abstract":"Innovative electric vertical take-off and landing (eVTOL) aircraft designs and operational concepts, driven by advancements in battery and electric motor technologies, seek to achieve superior safety records with increased system redundancy. Validating safe flight operations within verified flight envelope regions for passenger flights in densely populated urban environments remains a primary challenge. This paper establishes a framework for applying Hamilton–Jacobi reachability analysis to the full six-degree-of-freedom (6-DOF) dynamics of the NASA Tiltwing vehicle, verifying the flight envelope during the flight mode transition between near-hover and cruise flight, which prevents loss of control of the vehicle and ensures recoverability to safe trim conditions. This involves first verifying the nominal flight mode transition path as a series of trim points, defining the safe flight envelope using reachability, and decomposing the system dynamics into longitudinal and lateral subsystems. Our formulation guarantees the computed envelope's robustness against modeling errors and uncertainties, and the usage of state decomposition significantly improves the tractability of the reachability computation. The result is validated through Monte Carlo 6-DOF nonlinear simulation of vehicle dynamics, demonstrating that the vehicle states within the flight envelope can successfully recover to trim states and continue the flight mode transition safely.","PeriodicalId":50017,"journal":{"name":"Journal of the American Helicopter Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135214617","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

Evaluation of Helicopter Ship Deck Landing Control Laws in Piloted Simulations 直升机舰船甲板着舰控制律在有人驾驶仿真中的评价

4区工程技术

Journal of the American Helicopter Society Pub Date : 2023-01-01 DOI: 10.4050/jahs.69.012002

Arti Kalra, Alexander Štrbac, Malte-Jörn Maibach

{"title":"Evaluation of Helicopter Ship Deck Landing Control Laws in Piloted Simulations","authors":"Arti Kalra, Alexander Štrbac, Malte-Jörn Maibach","doi":"10.4050/jahs.69.012002","DOIUrl":"https://doi.org/10.4050/jahs.69.012002","url":null,"abstract":"This paper describes the implementation and the evaluation of newly designed helicopter ship deck landing control modes in a piloted simulation study. The ship deck landing modes are embedded in a model-following controller architecture. The employed control design is a complete model-following control system, which imposes the desired command model dynamics on the controlled helicopter. Different command types combined with various hold functions are implemented to make the task easier for the pilots. Three basic command modes and three advanced command modes, one without ship communication and two with ship communication, are implemented. A piloted simulation study was performed in a simulator to evaluate and compare the implemented control modes within a complete maritime scenario design. The evaluation of control modes is based on the success of helicopter ship deck landings which is assessed by a quantitative as well as a qualitative assessment. Simulation results demonstrate that the advanced command modes improved the task performance as well as reduced the pilot workload extensively in comparison to the basic command modes.","PeriodicalId":50017,"journal":{"name":"Journal of the American Helicopter Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136306063","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

A Computational Examination of Side-by-Side Rotors in Ground Effect 地效应中并排转子的计算检验

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2023-01-01 DOI: 10.4050/jahs.68.032007

R. Healy, J. McCauley, F. Gandhi, O. Sahni

{"title":"A Computational Examination of Side-by-Side Rotors in Ground Effect","authors":"R. Healy, J. McCauley, F. Gandhi, O. Sahni","doi":"10.4050/jahs.68.032007","DOIUrl":"https://doi.org/10.4050/jahs.68.032007","url":null,"abstract":"This study investigates the interactional aerodynamics of hovering side-by-side rotors in ground effect. The 5.5-ft diameter, three-bladed fixed-pitched rotors are simulated using computational fluid dynamics at a targeted 5 lb/ft2 disk loading. Simulations are performed using the commercial Navier–Stokes solver, AcuSolve®, with a delayed detached eddy simulation model. Side-by-side rotors are simulated at two heights above the ground (H/D = 0.5 and H/D = 1), and with two hub–hub separation distances (3R and 2.5R). The performance of side-by-side rotors in ground effect (IGE) is compared to isolated rotors out of ground effect. Between the side-by-side rotors IGE, a highly turbulent mixing region is identified where the wakes of each rotor collide. The flow fountains upwards, as well as exits outwards (along a direction normal to a plane connecting the two rotor hubs) with fountaining between the rotors reaching up to 0.75D above the ground. As blades at H/D = 0.5 traverse the highly turbulent flow, strong vibratory loading is induced and a thrust loss is observed over the outboard sections between the rotors that is large enough to negate any nominal ground effect benefits inboard. Side-by-side rotors at H/D = 0.5 with 2.5R hub–hub spacing produce peak-to-peak thrust oscillations up to 16% of the steady thrust. Rotors placed higher, at H/D = 1 are positioned above the turbulent mixing flow and produce significantly lower vibratory loads. The spacing between rotors at H/D = 0.5 and 3R hub–hub separation allows strong vortical structures to develop between the rotors which move from side to side over multiple revolutions. When the vorticity moves closer to one of the rotors, it produces a greater lift deficit over the outboard region and a stronger vibratory loading. For rotors closer together, at H/D = 0.5 and 2.5R separation, the vortical structures between rotors are constrained to a more concentrated area and show less side-to-side drift.","PeriodicalId":50017,"journal":{"name":"Journal of the American Helicopter Society","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70218696","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

Implementation and Linearization of State-Space Free-Vortex Wake Models for Rotary- and Flapping-Wing Vehicles 旋翼和扑翼飞行器状态空间自由涡尾迹模型的实现和线性化

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2023-01-01 DOI: 10.4050/jahs.68.042004

Umberto Saetti, J. Horn

引用次数: 0

Large Eddy Simulation for Empirical Modeling of the Wake of Three Urban Air Mobility Vehicles 三种城市空中机动车辆尾流经验建模的大涡模拟

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2023-01-01 DOI: 10.4050/jahs.68.042002

Denis-Gabriel Caprace, A. Ning

{"title":"Large Eddy Simulation for Empirical Modeling of the Wake of Three Urban Air Mobility Vehicles","authors":"Denis-Gabriel Caprace, A. Ning","doi":"10.4050/jahs.68.042002","DOIUrl":"https://doi.org/10.4050/jahs.68.042002","url":null,"abstract":"Recent advances in urban air mobility have driven the development of many new vertical take-off and landing (VTOL) concepts. These vehicles often feature original designs departing from the conventional helicopter configuration. Due to their novelty, the characteristics of the supervortices forming in the wake of such aircraft are unknown. However, these vortices may endanger any other vehicle evolving in their close proximity, owing to potentially large induced velocities. Therefore, improved knowledge about the wakes of VTOL vehicles is needed to guarantee safe urban air mobility operations. In this work, we study the wake of three VTOL aircraft in cruise by means of large eddy simulation. We present a two-stage numerical procedure that enables the simulation of long wake ages at a limited computational cost. Our simulations reveal that the wakes of rotary vehicles (quadcopter and side-by-side helicopter) feature larger wake vortex cores than an isolated wing. Their decay is also accelerated due to self-induced turbulence generated during the wake roll-up. A tilt-wing wake, on the other hand, is moderately turbulent and has smaller vortex cores than the wing. Finally, we introduce an empirical model of the vortex circulation distribution that enables fast prediction of wake-induced velocities, within a 2% error of the simulation results on average.","PeriodicalId":50017,"journal":{"name":"Journal of the American Helicopter Society","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70219532","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

Effects of Ambient Conditions on Helicopter Harmonic Noise Radiation: Theory and Experiment 环境条件对直升机谐波噪声辐射的影响:理论与实验

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2023-01-01 DOI: 10.4050/jahs.69.012005

Eric Greenwood, Ben W. Sim, D. D. Boyd, Jr.

{"title":"Effects of Ambient Conditions on Helicopter Harmonic Noise Radiation: Theory and Experiment","authors":"Eric Greenwood, Ben W. Sim, D. D. Boyd, Jr.","doi":"10.4050/jahs.69.012005","DOIUrl":"https://doi.org/10.4050/jahs.69.012005","url":null,"abstract":"The effects of ambient atmospheric conditions, air temperature, and density on rotor harmonic noise radiation are characterized using theoretical models and experimental measurements of helicopter noise collected at three different test sites at elevations ranging from sea level to 7000 ft above sea level. Significant changes in the thickness, loading, and blade–vortex interaction noise levels and radiation directions are observed across the different test sites for an AS350 helicopter flying at the same indicated airspeed and gross weight. However, the radiated noise is shown to scale with ambient pressure when the flight condition of the helicopter is defined in nondimensional terms. Although the effective tip Mach number is identified as the primary governing parameter for thickness noise, the nondimensional weight coefficient also impacts lower harmonic loading noise levels, which contribute strongly to low-frequency harmonic noise radiation both in and out of the plane of the horizon. Strategies for maintaining the same nondimensional rotor operating condition under different ambient conditions are developed using an analytical model of single main rotor helicopter trim and confirmed using a CAMRAD II model of the AS350 helicopter. The ability of the Fundamental Rotorcraft Acoustics Modeling from Experiments (FRAME) technique to generalize noise measurements made under one set of ambient conditions to make accurate noise predictions under other ambient conditions is also validated.","PeriodicalId":50017,"journal":{"name":"Journal of the American Helicopter Society","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70219808","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

Autorotation Transfer of Training: Effects of Helicopter Dynamics 训练的自旋转移:直升机动力学的影响

4区工程技术

Journal of the American Helicopter Society Pub Date : 2023-01-01 DOI: 10.4050/jahs.69.022007

Paolo Francesco Scaramuzzino, Daan M. Pool, Marilena D. Pavel, Olaf Stroosma, Giuseppe Quaranta, Max Mulder

{"title":"Autorotation Transfer of Training: Effects of Helicopter Dynamics","authors":"Paolo Francesco Scaramuzzino, Daan M. Pool, Marilena D. Pavel, Olaf Stroosma, Giuseppe Quaranta, Max Mulder","doi":"10.4050/jahs.69.022007","DOIUrl":"https://doi.org/10.4050/jahs.69.022007","url":null,"abstract":"This paper analyzes the effects of the helicopter dynamics on pilots' learning process and transfer of learned skills during autorotation training. A quasi-transfer-of-training experiment was performed with 10 experienced helicopter pilots in the SIMONA moving-base flight simulator at Delft University of Technology. Pilots had to control an in-house flight dynamics model setup to simulate two types of helicopter dynamics: (1) a “hard” dynamics characterized by a low autorotative flare index requiring high pilot control compensation and (2) a “easy” dynamics characterized by a high autorotative flare index with low pilot control compensation required. Two groups of pilots tested these types of dynamics in a different training sequence: hard-easy-hard (HEH group) and easy-hard-easy (EHE group). The main conclusion of this study proved that simulator training for autorotation can best start with pilots training in the most resource demanding condition. A more challenging helicopter's dynamics will require higher pilot agility and more rapid responses to his/her perceptual changes. This will result in pilots developing more robust and adaptable flying skills. Indeed, a clear positive transfer of training effect was observed in the experiment presented in this paper in terms of acquired pilot skills in the HEH group, but not the EHE group. Positive transfer was especially observed in terms of reduced rate of descent at touchdown. The two groups differed in the control strategy applied, with the HEH group having developed a control technique mimicking more closely the one adopted in a real helicopter.","PeriodicalId":50017,"journal":{"name":"Journal of the American Helicopter Society","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135505049","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

Improved Gust Tolerance of a Cyclocopter UAV Using Onboard Flow Sensing 利用机载流量传感改进旋翼无人机阵风容忍度

IF 1.5 4区工程技术

Journal of the American Helicopter Society Pub Date : 2023-01-01 DOI: 10.4050/jahs.68.032011

Elena Shrestha, Derrick W. Yeo, Vikram Hrishikeshavan, I. Chopra

{"title":"Improved Gust Tolerance of a Cyclocopter UAV Using Onboard Flow Sensing","authors":"Elena Shrestha, Derrick W. Yeo, Vikram Hrishikeshavan, I. Chopra","doi":"10.4050/jahs.68.032011","DOIUrl":"https://doi.org/10.4050/jahs.68.032011","url":null,"abstract":"This paper describes the gust rejection study of a twin-cyclocopter micro air vehicle with two cyclorotors and an anti-torque nose rotor. A gust rejection controller relying on velocity feedback and onboard flow sensing was implemented in a closed-loop feedback system. Tethered experiments were conducted with the vehicle mounted on a 6-DOF stand in front of a synthetic gust generation device capable of providing up to 4 m/s step gust input. Planar gusts along the longitudinal and lateral axis of the cyclocopter and crosswinds were systematically studied. Both pitch control (varying nose rotor rpm) and thrust vectoring control strategies were evaluated to counteract perturbation along the longitudinal axis, while the cyclocopter used differential rotational speed of the cyclorotors for lateral gusts. Results showed that thrust vectoring was more effective than pitch control in reducing displacement from gust. Pitch control using the position feedback controller resulted in a maximum gust tolerance of 2.8 m/s with a duration of 3 s. while thrust vector control using the combined flow feedback and position feedback controller was able to withstand 4 m/s step gust input with 1 s duration with only 0.01 m displacement. In addition, flow feedback was more effective than position feedback in minimizing position error. The cyclocopter was also able to mitigate step gusts of 2.8 m/s in magnitude and 3 s duration with crosswind components at 30 deg from the longitudinal axis. The difference in performance can be attributed to the cyclocopter's unique thrust vectoring capability.","PeriodicalId":50017,"journal":{"name":"Journal of the American Helicopter Society","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70219367","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

Whirl Flutter Test of Swept-Tip Tiltrotor Blades 倾转旋翼后倾桨叶旋涡颤振试验

4区工程技术

Journal of the American Helicopter Society Pub Date : 2023-01-01 DOI: 10.4050/jahs.69.012010

James Sutherland, Frederick Tsai, Anubhav Datta

引用次数: 0