Control-Oriented Physical Input Modelling for a Helicopter UAV

It has become standard in the helicopter UAV control literature to use the main and tail rotor thrusts, and the main rotor flapping angles as inputs. However, the physically-controllable inputs are servomotors which actuate the main rotor cyclic and collective pitch, and the tail rotor collective pitch. Precise treatments of the helicopter model exist which study the physical inputs. However, these models remain intractable for practical implementation motivating researchers to use rough approximations such as simple gain relationships between thrust and collective. We propose and identify a physical input model which retains the accuracy of a general model but is algebraically simple enough for its use in control design. As a result of experimental validation, the vehicle’s velocity is incorporated into the model to improve its accuracy.     

基于FLUENT的机翼损伤小型无人机气动分析

研究小型无人机机翼不同程度受损条件下无人机气动特性,仿真无人机损伤多少比例机翼时可保持飞行。设计一个无人机模型,研究基于有限元分析的机翼损伤下的气动分析。在CATIA三维软件中对无人机建模,在ANSYS ICEM中进行模型曲面划分与流场网格划分,ANSYS FLUENT中进行气动分析。先分析完整机翼的无人机模型,再逐步切除一定比例的机翼,对比分析机翼损伤前后的气动特性,得出切除多少比例面积的翼面时无人机模型仍可保持飞行,为将来实际无人机设计和风洞试验提供依据。     

飞行器气动力参数辨识

基于飞行器法向过载方程,首先采用逐步回归分析方法对气动力系数的多元线性回归模型进行因子筛选,确定气动模型结构,然后用逐步回归分析法的结果作为初值,用实时递推最小二乘法估计气动力参数。     

Experimental Testing of a Hybrid Power Plant for a Dirigible UAV

Dirigibles have the ability to take off and land vertically, hover and maintain lift without consuming energy, and can be easily deflated for packaging and transportation. As such, dirigibles are well suited for surveillance and surveyance missions such as rescue and aid operations after disasters. This paper reviews hybrid dirigible UAV design considerations, then presents a novel hybrid power plant design. The hybrid power plant design consists of a 2-stroke 4cc glow engine in-line with a brushless DC motor/ generator and variable pitch propeller. The experimental results have shown that the hybrid power plant is capable of producing a power output of 148.4 W.     

Two-Step System Identification and Trajectory Tracking Control of a Small Fixed-Wing UAV

An approach for obtaining dynamically feasible reference trajectories and feedback controllers for a small unmanned aerial vehicle (UAV) based on an aerodynamic model derived from flight tests is presented. The modeling method utilizes stepwise multiple regression to determine relevant explanatory terms for the aerodynamic coefficients. A dynamically feasible trajectory is then obtained through the solution of an optimal control problem using pseudospectral optimal control software. Discrete-time feedback controllers are further designed to regulate the vehicle along the desired reference trajectory. Simulations in a realistic operational environment as well as flight testing of the feedback controllers on the aircraft platform demonstrate the capabilities of the approach.     

Modelling of UAV formation flight using 3D potential field

In this paper, we present a solution for formation flight and formation reconfiguration of unmanned aerial vehicles (UAVs). Based on a virtual leader approach, combined with an extended local potential field, the method is universal applicable by driving the vehicle’s auto pilot. The solution is verified, using a group of UAVs based on a simplified small scale helicopter, which is simulated in MATLAB^TM/Simulink^TM. As necessary for helicopters, the potential field approach is realized in 3D including obstacle and collision avoidance. The collision avoidance strategy could be used separately for the sense and avoid problem.     

Experimental evaluation of fault diagnosis in a skew-configured UAV sensor system

This paper presents an experimental evaluation of a hybrid fault detection and isolation scheme against three successive faults in skew-configured inertial sensors of an unmanned aerial vehicle (UAV). An additional small and low-cost inertial measurement unit is installed with a skewed angle to a primary inertial measurement unit. A parity space method and an in-lane monitoring method are combined to increase system tolerance to the occurrence of multiple successive faults during flight. The first and second faults are detected and isolated by the parity space method. The third fault is detected by the parity space method and isolated by the in-lane monitoring method based on the discrete wavelet transform. Hardware in-the-loop tests and flight experiments with a fixed-wing UAV are performed to verify the performance of the proposed fault diagnosis scheme.     

深度残差网络的无人机多目标识别

传统目标识别算法中,经典的区域建议网络(RPN)在提取目标候选区域时计算量 大,时间复杂度较高,因此提出一种级联区域建议网络(CRPN)的搜索模式对其进行改善。此外, 深层次的卷积神经网络训练中易产生退化现象,而引入残差学习的深度残差网络(ResNet),能 够有效抑制该现象。对多种不同深度以及不同参数的网络模型进行研究,将两层残差学习模块 与三层残差学习模块结合使用,设计出一种占用内存更小、时间复杂度更低的新型多捷联式残 差网络模型(Mu-ResNet)。采用 Mu-ResNet 与 CRPN 结合的网络模型在无人机目标数据集以及 PASCAL VOC 数据集上进行多目标识别测试,较使用 ResNet 与 RPN 结合的网络模型,识别准 确率提升了近 2 个百分点。     

2011 International Conference on Modelling,Identification and Control

June 26-29,2011 Shanghai,China The 2011 International Conference on Modelling,Identification and Control (ICMIC 2011)issponsored by International Journal of Modelling,Identification and     

基于预训练模型与无人机可见光影像的树种识别

提高图像质量与利用新的图像分类方法是提高遥感图像树种识别精度两个突破口. 本文基于VGG16的预训练模型与无人机可见光影像进行杉木、马尾松2个树种识别研究. 利用大疆精灵4RTK无人机, 搭载FC6310R相机, 采集南平市和三明市的杉木和马尾松人工纯林彩色图像. 通过图像预处理、标注、裁剪和增强等环节构建UAVTree2k和UAVTree20k两个数据集. 基于UAVTree2k数据集和VGG16模型在ImageNet数据集的预训练模型, 重新训练3个全连接层和Sigmoid层, 研究探讨不同迭代次数、不同批次大小、不同训练集和测试集划分比例对识别精度的影像. 研究结果表明, 当迭代次数为40、批次大小为16、训练集和测试集为6:4时, 模型识别效果最好, 测试精度达到98.63%; 小样本下, 基于VGG16的预训练模型具有良好的特征学习能力.     

Effectiveness of a Camera as a UAV Mounted Search Sensor for Target Detection: An Experimental Investigation

In this paper, we consider a problem of autonomous search using single or multiple Unmanned Ariel Vehicles (UAVs) mounted with downward-facing cameras. A model of the effectiveness of the search sensor, camera, in this case, is essential for developing strategies for optimal deployment and path planning of UAVs for efficient search. The probability of detection of a target of interest as a function of its distance from the point directly below the camera is used to model the search effectiveness. We carried out experiments and obtained a search effectiveness model for a camera in the laboratory environment using ArUco markers and triangular shapes as targets.

     

PID and LQ Regulation of a Multirotor Attitude: Mathematical Modelling, Simulations and Experimental Results

Multirotors have been recognized to be particularly interesting for surveillance, search and rescue, imaging and more, because of their several advantages as the high maneuverability and the vertical take off and landing capability. This paper presents the experimental results of the application of a Proportional Integral Derivative control law and a Linear Quadratic Regulation technique to the attitude of a multirotor. The reader is driven through all the main steps required to reach this goal, starting from the derivation of the mathematical model and the control laws, to the simulations and the experimental tests.     

基于GPS/INS的无人机物流配送路径识别与控制

当前无人机物流配送路径识别方法识别精准度差,控制效果难以达到人们满意的效果。为了解决上述问题,基于GPS/INS技术研究了一种新的无人机物流配送路径识别与控制方法,对无人机物流配送轨迹进行识别,分别识别了无人机横滚运动轨迹、航向运动轨迹和俯仰运动轨迹,基于GPS/INS技术设计了无人机物流配送导航控制方法,给出了导航控制程序。实验结果表明,基于GPS/INS的无人机物流配送路径识别与控制方法能够有效提高UAV速度与加速度,增强识别精度,无人机飞行高度的控制精准度相比较于传统方法提高了11.25%。     

Experimental Approach for Evaluating an UAV COTS-Based Embedded Sensors System

Fixed-wing Unmanned Aerial Vehicles (UAVs) are a class of UAVs which present many advantages notably long range of action. However, design of this kind of UAVs requires heavy logistics like outdoor tests, runways and experimented pilots. These constraints impact the development of embedded systems for fixed-wing UAVs. The purpose of this paper is to present an experimental approach for evaluating an embedded sensors system of a micro-fixed-wing UAV. Our idea is to test the sensors system using a vehicle that emulate the behavior of this UAV but without the constraints imposed by flight experimentations. Looking for the best emulation vehicle, first a theoretical and then an experimental study is conducted on a mobile robot and a bicycle models. We also show that, contrary to trend in literature, a mobile robot is not the optimal choice to emulate a fixed-wing UAV.     

基于场景识别的无人机自主着陆组合导航研究

研究无人机自主着陆阶段的组合导航问题,现有绝大多数是GPS/INS的组合导航,其中状态量的位置信息也都选择了传统的纬度、经度和海拔高度.为了适应着陆场景识别导航,提出了一种基于场景识别/INS的无人机自主着陆组合导航新方法.从机场原点指向飞机的矢量相对机场的俯仰角、方位角及矢量长度作为卡尔曼滤波状态量的位置信息,组合导航中量测信息是从飞机上的摄像机所获得的机场特征点在摄像机所摄图像中的位置(坐标).通过对方法的分析及仿真,结果验证了方法在无人机自主着陆阶段组合导航中,稳定性和快速性等识别性能较好.     

Parametric Performance Contracts: Non-Markovian Loop Modelling and an Experimental Evaluation

Even with todays hardware improvements, performance problems are still common in many software systems. An approach to tackle this problem for component-based software architectures is to predict the performance during early development stages by combining performance specifications of prefabricated components. Many existing methods in the area of component-based performance prediction neglect several influence factors on the performance of a component. In this paper, we present a method to calculate the performance of component services while including influences of external services and different usages. We use stochatic regular expressions with non-Markovian loop iterations to model the abstract control flow of a software component and probability mass functions to specify the time consumption of internal and external services in a fine grain way. An experimental evaluation is reported comparing results of the approach with measurements on a component-based webserver. The evaluation yields that using measured data as inputs, our approach can predict the mean response time of a service with less than 2 percent deviation from measurements taken when executing the service in our scenarios.     

An Initial Experimental Assessment of the Dynamic Modelling in UML

The goal of this empirical study is to compare the semantic comprehension of three different notations for representing the dynamic behaviour in unified modelling language (UML): (a) sequence diagrams, (b) collaboration diagrams, and (c) state diagrams. Eighteen students of Informatics analysed the three types of diagrams within three different application domains. We performed a 3 × 3 factorial experimental design with repeated measures. The metrics collected were total time and total score. The main conclusion of this study is that the comprehension of the dynamic modelling in object-oriented designs depends on the diagram type and on the complexity of the document. The software project design written in the UML notation is more comprehensible, when the dynamic behaviour is modelled in a sequence diagram. While if it is implemented using a collaboration diagram, the design turns out to be less comprehensible as the application domain, and consequently, the document is more complex.     

一种新型无人飞行器系统的设计与实现

介绍了一种新型无人飞行器(飞艇)系统的设计与实现,它主要是基于移动通讯原理来实现超视距动态实时监测遥控和程序控制功能;主要阐述了其实现的原理以及设计方案,此外,在原有机械部分的基础上进行了改进与创新,接着分析了构成系统的各部分功能;其中,在保证稳定性、快速性和准确性的基础上,为了节省成本,主要以单片机STC89C51RC和双音多频解码集成芯片MT8870为核心,辅以ISD1420高保真语音录放IC一起构成了主控系统;最后对此新型无人飞行器进行了实验,证实了其可行性.     

高空滑翔UUV气动参数估算与气动特性分析

研究水下航行器,针对无人水下航行器无法同时大幅度提高航速和航程的现状,为优化无人水下航行器气动特性,增强系统的稳定性,提出了高空滑翔无人水下航行器(UUV)总体气动布局进行设计.对气动特性进行分析,根据飞机和导弹气动参数的估算方法,通过类比的方式,对升力系数、阻力系数、俯仰力矩系数、航向静导数、动导数和操纵导数等主要气...