International Journal of Micro Air Vehicles最新文献_第9页

In-flight model parameter and state estimation using gradient descent for high-speed flight 基于梯度下降的高速飞行模型参数与状态估计

IF 1.4 4区工程技术

International Journal of Micro Air Vehicles Pub Date : 2019-01-01 DOI: 10.1177/1756829319833685

S. Li, C. De Wagter, C. D. de Visser, Q. Chu, G. de Croon

{"title":"In-flight model parameter and state estimation using gradient descent for high-speed flight","authors":"S. Li, C. De Wagter, C. D. de Visser, Q. Chu, G. de Croon","doi":"10.1177/1756829319833685","DOIUrl":"https://doi.org/10.1177/1756829319833685","url":null,"abstract":"High-speed flight in GPS-denied environments is currently an important frontier in the research on autonomous flight of micro air vehicles. Autonomous drone races stimulate the advances in this area by representing a very challenging case with tight turns, texture-less floors, and dynamic spectators around the track. These properties hamper the use of standard visual odometry approaches and imply that the micro air vehicles will have to bridge considerable time intervals without position feedback. To this end, we propose an approach to trajectory estimation for drone racing that is computationally efficient and yet able to accurately estimate a micro air vehicle’s state (including biases) and parameters based on sparse, noisy observations of racing gates. The key concept of the approach is to optimize unknown and difficult-to-observe state variables so that the observations of the racing gates best fit with the known control inputs, estimated attitudes, and the quadrotor dynamics and aerodynamics during a time window. It is shown that a gradient-descent implementation of the proposed approach converges ∼4 times quicker to (approximately) correct bias values than a state-of-the-art 15-state extended Kalman filter. Moreover, it reaches a higher accuracy, as the predicted end-point of an open-loop turn is on average only ∼20 cm away from the actual end-point, while the extended Kalman filter and the gradient descent method with kinematic model only reach an accuracy of ∼50 cm. Although the approach is applied here to drone racing, it generalizes to other settings in which a micro air vehicle may only have sparse access to velocity and/or position measurements.","PeriodicalId":49053,"journal":{"name":"International Journal of Micro Air Vehicles","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1756829319833685","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42229575","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: 4

Editorial: MAV Special Collection 社论:MAV特别收藏

IF 1.4 4区工程技术

International Journal of Micro Air Vehicles Pub Date : 2019-01-01 DOI: 10.1177/1756829319870050

引用次数: 0

Passive stability enhancement with sails of a hovering flapping twin-wing robot 双翼悬停扑翼机器人的被动稳定性增强研究

IF 1.4 4区工程技术

International Journal of Micro Air Vehicles Pub Date : 2019-01-01 DOI: 10.1177/1756829319841817

H. Altartouri, A. Roshanbin, G. Andreolli, L. Fazzi, M. Karásek, M. Lalami, A. Preumont

引用次数: 7

Rotor performance enhancement through blade surging 通过叶片喘振提高转子性能

IF 1.4 4区工程技术

International Journal of Micro Air Vehicles Pub Date : 2019-01-01 DOI: 10.1177/1756829319844275

T. Bensebaa, T. Jardin, S. Prothin, N. Doué

引用次数: 0

Force and flowfield measurements to understand unsteady aerodynamics of cycloidal rotors in hover at ultra-low Reynolds numbers 超低雷诺数悬停摆线转子非定常空气动力学的力和流场测量

IF 1.4 4区工程技术

International Journal of Micro Air Vehicles Pub Date : 2019-01-01 DOI: 10.1177/1756829319833677

C. M. Reed, David A. Coleman, Moble Benedict

{"title":"Force and flowfield measurements to understand unsteady aerodynamics of cycloidal rotors in hover at ultra-low Reynolds numbers","authors":"C. M. Reed, David A. Coleman, Moble Benedict","doi":"10.1177/1756829319833677","DOIUrl":"https://doi.org/10.1177/1756829319833677","url":null,"abstract":"This paper provides a fundamental understanding of the unsteady fluid-dynamic phenomena on a cycloidal rotor blade operating at ultra-low Reynolds numbers (Re ∼ 18,000) by utilizing a combination of instantaneous blade force and flowfield measurements. The dynamic blade force coefficients were almost double the static ones, indicating the role of dynamic stall. For the dynamic case, the blade lift monotonically increased up to ±45° pitch amplitude; however, for the static case, the flow separated from the leading edge after around 15° with a large laminar separation bubble. There was significant asymmetry in the lift and drag coefficients between the upper and lower halves of the trajectory due to the flow curvature effects (virtual camber). The particle image velocimetry measured flowfield showed the dynamic stall process during the upper half to be significantly different from the lower half because of the reversal of dynamic virtual camber. Even at such low Reynolds numbers, the pressure forces, as opposed to viscous forces, were found to be dominant on the cyclorotor blade. The power required for rotation (rather than pitching power) dominated the total blade power.","PeriodicalId":49053,"journal":{"name":"International Journal of Micro Air Vehicles","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1756829319833677","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49246104","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

Experimental and computational investigation on interaction between nano rotor and aerodynamic rudder 纳米旋翼与气动舵相互作用的实验与计算研究

IF 1.4 4区工程技术

International Journal of Micro Air Vehicles Pub Date : 2019-01-01 DOI: 10.1177/1756829319866024

Dong-Keun Yang, Zhen Liu, Chen Bu, Shanyong Zhao

{"title":"Experimental and computational investigation on interaction between nano rotor and aerodynamic rudder","authors":"Dong-Keun Yang, Zhen Liu, Chen Bu, Shanyong Zhao","doi":"10.1177/1756829319866024","DOIUrl":"https://doi.org/10.1177/1756829319866024","url":null,"abstract":"The interference effect between the nano rotor and aerodynamic rudder was studied experimentally and computationally. Propulsive performance of nano rotor and aerodynamic performance of aerodynamic rudder were achieved experimentally. The disturbed flow field of nano rotor was also analyzed computationally to disclose the flow mechanics of the interaction. Results showed that the nano rotor has a great effect on the aerodynamic performance of aerodynamic rudder. The moment of aerodynamic rudder fluctuated with the rotor-to-rudder spacing and achieved the smallest value at the spacing of 0.5R. And the moment of aerodynamic rudder varied with deflection angle linearly. Aerodynamic rudder influenced the propulsion performance of the nano rotor slightly. The thrust coefficient and torque coefficient increased a little with spacing but changed slightly with the deflection angle. Numerical simulation showed that aerodynamic rudder blocked the flow field of the nano rotor and the counterclockwise rotation of the rotor drives the flow in the downstream rotating in a counterclockwise direction resulting in the different angle of attack between left and right rudder surface.","PeriodicalId":49053,"journal":{"name":"International Journal of Micro Air Vehicles","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1756829319866024","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43129487","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

Numerical investigation of the low-frequency flow oscillation over a NACA-0012 aerofoil at the inception of stall NACA-0012型机翼失速初期低频流动振荡的数值研究

IF 1.4 4区工程技术

International Journal of Micro Air Vehicles Pub Date : 2019-01-01 DOI: 10.1177/1756829319833687

Yasir A. Elawad, E. Eljack

{"title":"Numerical investigation of the low-frequency flow oscillation over a NACA-0012 aerofoil at the inception of stall","authors":"Yasir A. Elawad, E. Eljack","doi":"10.1177/1756829319833687","DOIUrl":"https://doi.org/10.1177/1756829319833687","url":null,"abstract":"High-fidelity large eddy simulation is carried out for the flow field around a NACA-0012 aerofoil at Reynolds number of 9 × 10 4 , Mach number of 0.4, and various angles of attack around the onset of stall. The laminar separation bubble is formed on the suction surface of the aerofoil and is constituted by the reattached shear layer. At these conditions, the laminar separation bubble is unstable and switches between a short bubble and an open bubble. The instability of the laminar separation bubble triggers a low-frequency flow oscillation. The aerodynamic coefficients oscillate accordingly at a low frequency. The lift and the drag coefficients compare very well to recent high-accuracy experimental data, and the lift leads the drag by a phase shift of π / 2 . The mean lift coefficient peaks at the angle of attack of 10.25 ° , in total agreement with the experimental data. The spectra of the lift coefficient does not show a significant low-frequency peak at angles of attack lower than or equal the stall angle of attack ( 10.25 ° ). At higher angles of attack, the spectra show two low-frequency peaks and the low-frequency flow oscillation is fully developed at the angle of attack of 11.0 ° . The behaviour of the flow-field and changes in the turbulent kinetic energy over one low-frequency flow oscillation cycle are described qualitatively.","PeriodicalId":49053,"journal":{"name":"International Journal of Micro Air Vehicles","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1756829319833687","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46410776","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: 6

Attitude control of tiltwing aircraft using a wing-fixed coordinate system and incremental nonlinear dynamic inversion 基于机翼固定坐标系和增量非线性动力学反演的倾斜翼飞机姿态控制

IF 1.4 4区工程技术

International Journal of Micro Air Vehicles Pub Date : 2019-01-01 DOI: 10.1177/1756829319861370

F. Binz, T. Islam, D. Moormann

引用次数: 10

Aerodynamics of MAV rotors in ground and corner effect MAV旋翼在地面和转角影响下的空气动力学

IF 1.4 4区工程技术

International Journal of Micro Air Vehicles Pub Date : 2019-01-01 DOI: 10.1177/1756829319861596

S. Prothin, C. Fernandez Escudero, N. Doué, T. Jardin

{"title":"Aerodynamics of MAV rotors in ground and corner effect","authors":"S. Prothin, C. Fernandez Escudero, N. Doué, T. Jardin","doi":"10.1177/1756829319861596","DOIUrl":"https://doi.org/10.1177/1756829319861596","url":null,"abstract":"The work presented in this paper is part of a project called ARChEaN (Aerodynamic of Rotors in Confined ENvironment) whose objective is to study the interactions of a micro drone rotor with its surroundings in the case of flight in enclosed environments such as those encountered, for example, in archeological exploration of caves. To do so the influence of the environment (walls, ground, ceiling, etc) on the rotor’s aerodynamic performance as well as on the flow field between the rotor and the surroundings is studied. This paper focuses on two different configurations, flight near the ground and flight near a corner (wall and ground), and the results are analyzed and compared to a general free flight case (i.e. far away from any obstacle). In order to carry out this analysis both numerical and experimental approaches are conducted. The objective is to validate the numerical model with the results obtained experimentally and to benefit from the advantages of both approaches in terms of flow analysis. This research work will provide knowledge on how to operate these systems as to minimize the possible negative environment disturbances, reduce power consumption and predict the micro drone’s behaviour during enclosed flights.","PeriodicalId":49053,"journal":{"name":"International Journal of Micro Air Vehicles","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1756829319861596","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47662693","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: 8

Computational study on the aerodynamics of a long-shrouded contra-rotating rotor in hover 悬停长冠对转旋翼空气动力学计算研究

IF 1.4 4区工程技术

International Journal of Micro Air Vehicles Pub Date : 2019-01-01 DOI: 10.1177/1756829319833686

C. Huo, P. Lv, A. Sun

{"title":"Computational study on the aerodynamics of a long-shrouded contra-rotating rotor in hover","authors":"C. Huo, P. Lv, A. Sun","doi":"10.1177/1756829319833686","DOIUrl":"https://doi.org/10.1177/1756829319833686","url":null,"abstract":"This paper aims to investigate the aerodynamics including the global performance and flow characteristics of a long-shrouded contra-rotating rotor by developing a full 3D RANS computation. Through validations by current experiments on the same shrouded contra-rotating rotor, the computation using sliding mesh method and the computational zone with an extended nozzle downstream flow field effectively works; the time-averaged solution of the unsteady computation reveals that more uniform flow presents after the downstream rotor, which implies that the rear rotor rotating at opposite direction greatly compensates and reduces the wake; the unsteady computations further explore the flow field throughout the whole system, along the span and around blade tips. Complex flow patterns including the vortices and their interactions are indicated around the blade roots and tips. For further identifying rotor configurations, the rotor–rotor distance and switching two rotor speeds were studied. The computation reveals that setting the second rotor backwards decreases the wake scale but increases its intensity in the downstream nozzle zone. However, for the effect of switching speeds, computations cannot precisely solve the flow when the rear rotor under the windmill because of the upstream rotor rotating much faster than the other one. All the phenomena from computations well implement the experimental observations.","PeriodicalId":49053,"journal":{"name":"International Journal of Micro Air Vehicles","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1756829319833686","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46290395","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