Human Memory/Learning Inspired Control Method for Flapping-Wing Micro Air Vehicles

The problem of flapping motion control of Micro Air Vehicles (MAVs) with flapping wings was studied in this paper.Based upon the knowledge of skeletal and muscular components of hummingbird, a dynamic model for flapping wing wasdeveloped.A control scheme inspired by human memory and learning concept was constructed for wing motion control ofMAVs.The salient feature of the proposed control lies in its capabilities to improve the control performance by learning fromexperience and observation on its current and past behaviors, without the need for system dynamic information.Furthermore,the overall control scheme has a fairly simple structure and demands little online computations, making it attractive for real-timeimplementation on MAVs.Both theoretical analysis and computer simulation confirms its effectiveness.

Piezoelectric energy harvesting from morphing wing motions for micro air vehicles

Wing flapping and morphing can be very beneficial to managing the weight of micro air vehicles through coupling the aerodynamic forces with stability and control. In this letter, harvesting energy from the wing morphing is studied to power cameras, sensors, or communication devices of micro air vehicles and to aid in the management of their power. The aerodynamic loads on flapping wings are simulated using a three-dimensional unsteady vortex lattice method. Active wing shape morphing is considered to enhance the performance of the flapping motion. A gradient-based optimization algorithm is used to pinpoint the optimal kinematics maximizing the propellent efficiency. To benefit from the wing deformation, we place piezoelectric layers near the wing roots. Gauss law is used to estimate the electrical harvested power. We demonstrate that enough power can be generated to operate a camera. Numerical analysis shows the feasibility of exploiting wing morphing to harvest energy and improving the design and performance of micro air vehicles.

Micro air vehicle-motivated computational biomechanics in bio-flights:aerodynamics,flight dynamics and maneuvering stability

Aiming at developing an effective tool to unveil key mechanisms in bio-flight as well as to provide guidelines for bio-inspired micro air vehicles（MAVs） design,we propose a comprehensive computational framework,which integrates aerodynamics,flight dynamics,vehicle stability and maneuverability.This framework consists of（1） a Navier-Stokes unsteady aerodynamic model;（2） a linear finite element model for structural dynamics;（3） a fluidstructure interaction（FSI） model for coupled flexible wing aerodynamics aeroelasticity;（4） a free-flying rigid body dynamic（RBD） model utilizing the Newtonian-Euler equations of 6DoF motion;and（5） flight simulator accounting for realistic wing-body morphology,flapping-wing and body kinematics,and a coupling model accounting for the nonlinear 6DoF flight dynamics and stability of insect flapping flight.Results are presented based on hovering aerodynamics with rigid and flexible wings of hawkmoth and fruitfly.The present approach can support systematic analyses of bio- and bio-inspired flight.

Model Identification of a Micro Air Vehicle

This paper is focused on the model identification of a Micro Air Vehicle （MAV） in straight steady flight condition. The identification is based on input-output data collected from flight tests using both frequency and time dorrtain techniques. The vehicle is an in-house 40 cm wingspan airplane. Because of the complex coupled, multivariable and nonlinear dynamics of the aircraft, linear SISO structures for both the lateral and longitudinal models around a reference state were derived. The aim of the identification is to provide models that can be used in future development of control techniques for the MAV.

Development of the NWPU20 Micro Air Vehicle

This paper reports the design, construction, and operation of NWPU20 Micro Air Vehicle (MAV), which is the smallest that has, up to now, been developed in PR China. The miniaturization level in PR China makes smaller MAV, in our opinion, not possible to implement. The NWPU20 is a 20-centimeter span, battery powered, fixed-wing aircraft with an off-the-shelf color video camera that can transmit live video back to the ground station. The on-board electronic subsystems are smallest and lightest among the commercial products, including an 8-gram wireless video camera, an 8-gram receiver, a 5-gram electronic speed controller (ESC), two 4.5-gram fully proportional radio frequency control servos, and the total mass of NWPU20 is less than 80 grams. An experimental model was fabricated and tested in the Low Turbulent Flow Wind Tunnel (LTFWT) at Northwestern Polytechnical University (NWPU) to research low Reynolds number flow characteristics of the NWPU20. The result of the wind tunnel test shows that stall angle of attack of NWPU20 can reach 30°, which is higher than that of the general aircrafts, and the maximum lift-to-drag ratio of NWPU20 can nearly reach 6 at the angle of attack of 10°, which can satisfy design requirements of the NWPU20. A small-sized propulsion/torque testing system was developed to measure and analyze the propulsion and torque performances of the motor-propeller combination used in the NWPU20. A center of gravity (c.g.) testing apparatus was developed and used to adjust the c.g. of the NWPU20 so that it has good longitudinal static stability and control. The NWPU20 prototype has undergone successfully flight tests many times; it flies at 32 kilometers per hour, with an endurance of 15 minutes, and a maximum communications range of 300 meters. With the color video camera, NWPU20 successfully transmits real-time video back to the ground station. The success of NWPU20 proves preliminarily that 20-centimeter span micro air vehicle is feasible and usable.

Kinematic and Aerodynamic Modelling of Bi- and Quad-Wing Flapping Wing Micro-Air-Vehicle

A generic approach to model the kinematics and aerodynamics of flapping wing ornithopter has been followed, to model and analyze a flapping bi- and quad-wing ornithopter and to mimic flapping wing biosystems to produce lift and thrust for hovering and forward flight. Considerations are given to the motion of a rigid and thin bi-wing and quad-wing ornithopter in flapping and pitching motion with phase lag. Basic Unsteady Aerodynamic Approach incorporating salient features of viscous effect and leading-edge suction are utilized. Parametric study is carried out to reveal the aerodynamic characteristics of flapping bi- and quad-wing ornithopter flight characteristics and for comparative analysis with various selected simple models in the literature, in an effort to develop a flapping bi- and quad-wing ornithopter models. In spite of their simplicity, results obtained for both models are able to reveal the mechanism of lift and thrust, and compare well with other work.

Low-Power Operational Amplifier for Real-Time Signal Processing System of Micro Air Vehicle

A low-power complementary metal oxide semiconductor（CMOS） operational amplifier （op-amp） for real-time signal processing of micro air vehicle （MAV） is designed in this paper.Traditional folded cascode architecture with positive channel metal oxide semiconductor（PMOS） differential input transistors and sub-threshold technology are applied under the low supply voltage.Simulation results show that this amplifier has significantly low power,while maintaining almost the same gain,bandwidth and other key performances.The power required is only 0.12 mW,which is applicable to low-power and low-voltage real-time signal acquisition and processing system.

道路交通排放对周边环境影响的分析——以兰州市安宁区学府路为例

探究城市道路中机动车污染物的排放对周边环境的影响,对环境治理起着至关重要的作用。通常通过分析污染物的影响因素,来建立排放模型。根据研究尺度的不同,将应用较广泛的模型进行划分,并对模型原理、应用及存在不足等方面进行归纳和总结。为了探究学府路道路污染状况,选取COPERT模型进行污染物排放量的测算,并使用ANSYS软件模拟了道路交通排放对学府路周边环境的影响,得出了污染物地图。结果表明:学府路工作日内4项主要大气污染物NO_(2)、CO、PM_(2.5)、PM_(10)排放量分别为67.7、269.1、15.1和22.8 t。数量占10.0%的轻型货车排放贡献较大,分别占机动车NO_(2)和PM排放总量的50.5%和69.1%。通过模拟值与实测值的对比发现,COPERT模型对于中观尺度的研究具有较好的支撑。

Passive attitude stabilization of ionic-wind-powered micro air vehicles

The ionic-wind-powered Micro Air Vehicles(MAVs)can achieve a higher thrust-toweight ratio than other MAVs.However,this kind of MAV has not yet achieved controlled flight because of the unstable thrust produced by the ionic wind and the dynamic instability related to the small size.In this paper,a passive attitude stabilization method of the ionic-wind-powered MAV using air dampers is introduced.The key factors that influence the performance of the air dampers,including the layout,position,and area of the air dampers,are theoretically studied.The appropriate optimal position of the air dampers is also obtained by Monte Carlo stochastic simulations.Then the proposed passive attitude stabilization method is applied to the ionic-wind-powered MAVs of different wingspan(2 cm and 6.3 cm).Finally,the experimental results show that using the proposed method,attitude stabilization is achieved for the first time for the ionic-wind-powered MAV.Moreover,the altitude control of an ionic-wind-powered MAV with a wingspan of 6.3 cm is also demonstrated.

An experimental study of elastic properties of dragonfly-like flapping wings for use in biomimetic micro air vehicles(BMAVs)

This article studies the elastic properties of several biomimetic micro air vehicle（BMAV）wings that are based on a dragonfly wing.BMAVs are a new class of unmanned micro-sized air vehicles that mimic the flapping wing motion of flying biological organisms（e.g.,insects,birds,and bats）.Three structurally identical wings were fabricated using different materials：acrylonitrile butadiene styrene（ABS）,polylactic acid（PLA）,and acrylic.Simplified wing frame structures were fabricated from these materials and then a nanocomposite film was adhered to them which mimics the membrane of an actual dragonfly.These wings were then attached to an electromagnetic actuator and passively flapped at frequencies of 10-250 Hz.A three-dimensional high frame rate imaging system was used to capture the flapping motions of these wings at a resolution of 320 pixels x 240 pixels and 35000 frames per second.The maximum bending angle,maximum wing tip deflection,maximum wing tip twist angle,and wing tip twist speed of each wing were measured and compared to each other and the actual dragonfly wing.The results show that the ABS wing has considerable flexibility in the chordwise direction,whereas the PLA and acrylic wings show better conformity to an actual dragonfly wing in the spanwise direction.Past studies have shown that the aerodynamic performance of a BMAV flapping wing is enhanced if its chordwise flexibility is increased and its spanwise flexibility is reduced.Therefore,the ABS wing（fabricated using a 3D printer） shows the most promising results for future applications.

Multi-Object Tracking with Micro Aerial Vehicle

A simple yet efficient tracking framework is proposed for real-time multi-object tracking with micro aerial vehicles(MAVs). It's basic missions for MAVs to detect specific targets and then track them automatically. In our method, candidate regions are generated using the salient detection in each frame and then classified by an eural network. A kernelized correlation filter(KCF) is employed to track each target until it disappears or the peak-sidelobe ratio is lower than a threshold. Besides, we define the birth and death of each tracker for the targets. The tracker is recycled if its target disappears and can be assigned to a new target. The algorithm is evaluated on the PAFISS and UAV123 datasets. The results show a good performance on both the tracking accuracy and speed.

Implementation of VxWorks in autopilot for micro aerial vehicle based on PXA255 and FPGA

The overall hardware construction of autopilot within micro aerial vehicle is presented. The boot process of VxWorks real time operating system as well as the conception and function of board support package （BSP） is described. And the transplantation process of the VxWroks operat ing system into the hardware platform mentioned above is highlighted. It is shown from the final re sults that VxWorks has high stability and real time performance, ensuring accurate flight control and a smooth flight of the micro aerial vehicle.

Flight mechanism and design of biomimetic micro air vehicles

This paper summaries the investigations on natural flyers and development of bio-mimetic micro air vehicles(MAVs)at NUAA,China,where the authors have led a group to conduct research for a decade. The investigations include the studies of low Reynolds number aerodynamics,unsteady computational fluid dynamics and flight control for the fixed-wing MAVs,the bird-like MAVs,the dragonfly-like MAVs and the bee-like MAVs.

柔性扑翼微型飞行器升力和推力机理的风洞试验和飞行试验

为探讨柔性扑翼微型飞行器产生升力和推力的机理,在研究考虑柔性大变形扑翼气动力计算方法基础上,利用南京航空航天大学低速风洞进行了不同扑动频率、迎角、速度下微型扑翼升力、推力的变化和动态流场显示等风洞实验,并与计算结果进行了比较分析,为微型扑翼机的设计提供了的参考依据.自行研制的微型柔性结构扑翼机成功地进行了飞行试验.

基于MEMS加速度传感器的双轴倾角计及其应用

利用MEMS加速度传感器设计了双轴倾角计,并采用单片机进行了线性化和温度补偿,倾斜角以模拟量和数字量2种形式输出。该倾角计体积小、重量轻、精度高,能够很好地满足MAV姿态控制及其他应用的倾角测量。

微型飞行器的研究现状与关键技术

微型飞行器目前在国际上是一个研究热点 ,它突破了传统常规飞行器的设计和制作概念 ,是随着微米纳米科技和微电子机械系统 ( MEMS)的蓬勃兴起而发展起来的一个新的研究领域。本文介绍了国内外各种微型飞行器当前的研究发展状况 ,分析了微型飞行器研制中的一些关键技术 ,并对其未来发展前景作了展望。

微型扑翼飞行器机翼气动特性研究

依据微型扑翼飞行器产生升力和推力的机理,设计了一套能够快速、有效求得扑翼飞行器机翼气动特性的计算方法。计算程序通过V isual Basic和Fortran语言混合编程来实现,核心部分是利用改进的片条理论方法估算扑翼机翼的气动性能。计算结果与在西北工业大学微型飞行器专用风洞中所进行的吹风试验结果吻合良好,证明了该方法的正确性和有效性。在此基础上,研究了不同机翼平面形状、不同展弦比、不同上下扑时间比对微型扑翼飞行器机翼气动性能的影响,这些参数对微型飞行器的设计有一定的指导和参考意义。

微小型飞行器航向系统设计

从实用的角度出发,给出了微小型飞行器的航向系统(包括航向测量和航向控制)体系结构.设计了地磁航向、捷联航向、GPS航向等3种常用的航向测量手段在微小型系统中的实现方案,分析了其各自的优、缺点,提出了一种实用的、基于数据融合的航向获取方法.在航向测量的基础上,又设计了针对微小型飞行器的航向控制方案,并应用于某小型固定翼飞行器的飞行控制系统中.进行了自主飞行试验,取得了预期的试验效果.

微小型四旋翼飞行器的研究现状与关键技术

微小型化是世界无人机发展的重要方向之一。对一种新颖的微小型四旋翼无人飞行器进行了介绍,综合了微小型四旋翼飞行器的概念和特性,然后主要从机构设计和飞行控制两方面介绍了世界微小型四旋翼飞行器的发展现状,详细叙述了小型四旋翼飞行器的发展技术路线。在此基础之上,进一步分析了相关的关键技术问题,并对未来发展、应用前景作了展望。最后介绍了某微小型四旋翼飞行器研究进展情况。

基于改进互补滤波器的低成本微小飞行器姿态估计方法

针对微飞行器(MAV)在不同机动状态下如何获得对重力加速度的有效估计这一问题,提出一种具有增益调节机制的显性互补滤波器,对微飞行器类似周期性盘旋等典型状态,利用陀螺仪的测量和指示空速的估计构建了向心加速度补偿机制,使得基于重力加速度估计的互补滤波器能获得较为精确的姿态估计,并克服了传统互补滤波器对姿态估计进行重构的缺点。在比例积分补偿环节中,对俯仰角和横滚角的估计赋予不同的截止频率,使得比例增益和积分增益具有较好的自适应性。对比实验表明,姿态角估计误差能保持在±2°之内,与现有的典型滤波算法相比,该方法在算法效率和估计误差方面具有良好的综合性能,并适合用低成本的微惯性测量单元实现微飞行器的精确姿态估计。