模糊神经网络在机载相机稳像中的应用

针对解决微型飞行器空中拍摄的图像抖动问题,采用自组织递归区间二型模糊神经网络的函数逼近及泛化能力对微型飞行器上的相机振动规律进行模拟,预测机载相机的振动矢量.该自组织递归区间二型模糊神经网络的初始规则数为零,所有规则都是通过结构和参数同时在线学习来产生,网络结构学习采用的是在线区间二型模糊群集,提高自组织递归区间二型模糊神经网络的稳定性及计算精度.仿真结果表明：将自组织递归区间二型模糊神经网络与双BP神经网络进行对比,利用自组织递归区间二型模糊神经网络对微型飞行器相机振动矢量进行预测的精度高.     

Space on Earth: A Virtual Portal Between the Earth and Outer Space

Every time you text or call from your mobile phone, you may be unknowingly providing essential data that is being captured for public or commercial research. Valentina Croci describes how The Senseable City Lab at MIT and the Estonian group Positium LBS with the Department of Geography at the University of Tartu have been developing projects that enable us to sense the city, dynamically mapping social movement. Copyright © 2008 John Wiley & Sons, Ltd.     

3D imaging application in the studies of micro air vehicles

3D techniques are increasingly used in aerospace industry to improve quality and performance of aircrafts. This paper presents a 3D imaging technique for studying the aerodynamic shape and flight performance of micro air vehicles. 3D stereoscopic vision, based upon stroboscopic imaging, was utilized to obtain the 3D information of the aircraft's flexible aerodynamic surface. The aircraft models with deformable aerodynamic shape were designed and tested in a purpose-built wind tunnel experimental environment. After calculation of SIFT feature points and subdivision of triangular meshes, deformable surface of the aircraft's aerodynamic shape was represented. The aircraft's 3D visualization was used for analyzing unsteady deformation in the aerodynamic shape under external airflow disturbances. The results, together with aerodynamic forces measured in the experiment, will be useful to improve the flight performance and disturbance resistance ability of micro air vehicles.     

Dynamic Customer Value Management: Asset Values under Demand Uncertainty using Airline Yield Management and Related Techniques

The focus of this paper is to demonstrate the close links between the airline and the manufacturing industry in so far as some of their decision support problems are concerned. We show that the yield management (YM) problem for the airline characterized by perishable and limited resources has counterparts in manufacturing and retail although with some variations. In the process of establishing similarities we highlight the importance of the concept of value of assets/resources, known as bid price in the airline terminology, that ties the two together. Several examples of its calculations and uses are provided. We believe that this new paradigm will open up new avenues for profits for manufacturers in the new era of e-commerce where the businesses shall have to be increasingly customer centric including pricing functions.     

Application of Piezoelectric Actuator and Compliant Structures to Achieve Flapping Wing Motion for a MAV

Micro Aerial Vehicles(MAVs)are the smallest artificial aircraft.Most of the flapping wings MAVs are powered by electric motors of various capacities.We report in this paper the application of piezoelectric actuators as power system for a flapping wing MAV using a compliant displacement amplification mechanism.The actuator used for this application is a pre-stressed cut piece of TH-7R type Thunder actuator.A two-bar compliant mechanism with two flexures has been developed to convert the linear displacement into angular movement and amplification.The specimens were made from carbon fiber links and nylon flexures.We also proposed to use the product of frequency(F)and tip displacement(D),F*D as a criteria for the characterization of an amplifying mechanism.The best specimen according tO this criterion is obtained for a 5mm length flexure specimen made of three layers of nylon.The F*D value obtained for this specimen was 0.58 Hz.m.ANSYS finite element analysis results for different flexural thickness and Iengths were obtained and have been compared to the experimental results.The effect of both the thickness and length of the flexure on a particular arrangement has been discussed.     

小型飞行器跟踪地面运动目标技术研究

为提高跟踪与探测的能力,研究了利用小型飞行器对地面低速运动目标的跟踪技术.通过对初始盘旋半径、初始盘旋位置以及飞机倾斜角这几个参数之间关系的分析与仿真,表明随初始相对位置的不同,最小初始盘旋半径取值在200m～500m之间不等,飞机的倾斜角就能保持在30°以下,从而有效地实现对运动目标的实时贴近跟踪与探测,仿真结果对实际系统的应用具有重要的参考价值.     

基于DSP的微型飞行器磁罗盘

介绍了一种基于数字信号处理器(DSP)的微型飞行器(MAV)磁罗盘,它包括S/R电路,三轴磁阻传感器、信号调理电路和DSP。为了使传感器达到最高的精度,设计了S/R开关电路,消除了高磁场对输出的影响和温度变化引起的偏置误差。详细分析了磁罗盘的误差来源,给出其误差模型,并提出一种非线性、两步补偿算法,此算法也适用于其他存在比例、偏置和非正交误差的二维或三维传感器。经实验测试,该微型磁罗盘误差小于1.2,°且具有体积小、重量轻、功耗低、工作可靠等特点。     

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 operating system into the hardware platform mentioned above is highlighted.It is shown from the final results that VxWorks has high stability and real-time performance,ensuring accurate flight control and a smooth flight of the micro aerial vehicle.     

有人机控制无人机群空战多目标分配

针对集中式体系结构下的有人机-无人机群协同空战多目标分配问题,把目标威胁分为固有属性和动态属性两部分,分别建立了目标威胁系数层次结构模型和优势函数模型;根据空战态势的不同,提出了3种效率指标,建立了相应的代价函数;针对3种代价函数,运用离散粒子群算法进行了数值仿真研究,仿真结果表明所用的算法具有良好的收敛性,适合解算文...     

仿昆虫微飞行器仰俯姿态伺服控制器的设计

在风洞实验中,为动态地研究仿昆虫微飞行器的仰俯姿态控制方法,微飞行器的仰俯姿态需要根据安装于其上的微型多维力传感器的输出扭矩进行实时调节,为此设计了本伺服控制器。控制器采用STC增强型51单片机作为本控制器的核心,用模拟SPI接口与多维力传感器进行数据采集,采用电位器作为姿态角传感器,外接模数转换电路对姿态角度进行采样;采用步进电机实现对仰俯姿态角角速度的动态调节,并采用PID算法对姿态角角速度进行闭环反馈控制,以确保仰俯姿态角速度的控制精度。