两自由度仿生扑翼飞行机器人设计与运动分析

根据鸟类的飞行特性,设计了一种两自由度仿生扑翼飞行机器人。扑翼飞行机器人采用单电机驱动,能够实现扑动、扭转两自由度耦合运动,结构紧凑、运动高效,且机翼的运动形式接近鸟类。首先根据总体设计目标提出扑动-扭转耦合机构的运动特性要求,基于Adams建立了扑动-扭转耦合扑翼机构的运动学模型,通过仿真分析得到扑动和扭转运动的变化规律,并得到了翼尖轨迹曲线。扑动-扭转耦合机构的参数与设计结果达到了扑翼机构的运动要求,为仿生扑翼飞行机器人的设计和研究奠定了基础。     

仿鹰扑翼飞行器设计及多飞行模式的实现

现有仿生扑翼飞行器大多针对单一飞行模式进行设计与研究,无法实现复杂多变的飞行姿态。文中根据鹰的飞行特性,以空间RSSR机构和多连杆机构为出发点,设计了一种扑动-折叠-扭转的仿鹰扑翼机构,以实现多飞行模式。首先,通过鹰的仿生学研究,根据总体设计目标提出多飞行模式扑翼飞行器功能设计要求;其次,基于XFLR5建立了多飞行模式扑翼的气动力模型,分析了起飞、巡航、降落3种典型飞行模式下的翅翼气动力的变化规律;最后,根据飞行参数建立了机构的运动学模型,通过仿真分析得到扑翼在不同飞行模式下的运动变化规律及翼尖轨迹曲线。证明该扑翼机构具有良好的仿生运动特性和气动特性,为多飞行模式微型扑翼飞行器提供了设计参考。     

一种柔性微型扑翼设计及其气动力特性的试验研究

微型扑翼机以其优良的机动性、低噪音、低成本、执行任务的多功能性以及在现代高科技局部战争中的潜在应用价值而得到各科技先进国家的重视,投入了大量精力开展研究工作。在我国也已经初步开展对微型扑翼机研究。但由于与微型扑翼飞行相关的低雷诺数空气动力学研究还处于萌芽阶段,对微型扑翼的设计研究工作尚无可供指导的成熟理论和借鉴的经验,目前微型扑翼的设计研究基本上是以试验为主。本文参照动物的扑翼飞行实例和固定翼飞行器机翼设计的经验,在对扑翼飞行基本原理分析研究的基础上,设计制作了一种微型扑翼及扑翼的驱动机构,采用直流电动机作为动力,通过调节驱动电压来控制扑动的频率。并对该微型扑翼进行了空气动力特性试验,得到了微型扑翼的空气动力特性,并从中得出了影响扑动升力的一些因素。实验结果表明,具有柔性翼面的扑翼,其产生的升力和推力较高而且比较稳定。     

仿生扑翼结构优化设计及动力学仿真分析

针对目前飞行器结构复杂、效率低下及动作单一等问题,设计一种新型仿生扑翼飞行机构,仅通过单驱动装置即可实现机构扑翼的扑动、折叠、扭转等运动。依据生物尺度率设计扑翼机构的结构尺寸并对机构参数进行优化;通过SolidWorks构建仿生三维模型并基于ANSYS Workbench对扑翼机构进行有限元分析,得到扑翼齿轮组、曲柄、主翼杆等主要部件的总形变、应力、等效应变及主、副翼动力学运动参数,为仿生样机研制提供理论支持。     

仿生扑翼飞行器翅翼驱动方式的研究现状及展望

随着仿生扑翼飞行器的微型化，当扑翼飞行器达到昆虫置级的时候，任何复杂的运动系统都将面临难以实现的问题，翅翼的驱动方式也将面临新的挑战。本文从仿生飞行的历史与现状出发，论述了国内、外各类仿生扑翼飞行器翅翼驱动方式的研究状况。基于将昆翅视为柔性翅的观点，提出了仿生扑翼飞行器未来的研究前景翅翼在自适应变形状态下施以简单的节律运动将是仿生扑翼飞行器翅翼驱动方式的发展趋势之一。     

扑翼飞行器驱动机构的优化设计与仿真

针对目前双曲柄双摇杆结构应用在扑翼飞行器设计上较少,研究分析了扑翼驱动机构基于最小传动角最大的优化设计方法。在对传统四杆机构图解法的基础上,建立最小传动角与扑翼机架长度的关系模型。根据鸟类扑翼飞行的仿生条件,导出了机架安装角与扑翼扑动幅值、曲柄驱动角运动方程。利用MATLAB进行求解,确定驱动机构最优设计方案。建立扑翼驱动机构的虚拟样机,在ADAMS平台上进行虚拟运动仿真。结果表明,驱动机构的优化设计模型与扑翼扑动理论参数模型一致,此优化设计方法可行实用。     

仿生扑翼飞行简化力学模型及其实验研究

在研究鸟飞行机制的基础上，通过对扑翼飞行翅的简化和分析，建立了仿生扑翼飞行的简化力学模型，结合翼形导出了在一个扑动周期中翅上所产生的平均前进力和升力公式。实验证明了该简化力学模型及相应力学分析的可靠性和正确性。研究成果为进一步研制仿生扑翼飞行器提供了理论依据。     

基于模糊评判与优化的微型扑翼飞行器扑动机构综合设计方法

针对微型扑翼飞行器曲柄摇臂扑动机构,提出了影响扑动机构综合性能档方法对多种曲柄摇臂扑动机构方案进行优选,并对获选方案进行优化设计,在此基础上形成了微型扑翼飞行器扑动机构综合设计方法.样机研制和外场试飞证明了文中方法对提高扑动机构综合性能是有效的.     

可变幅扑翼飞行器设计及多飞行模式实现

针对目前扑翼飞行器飞行模式单一,无法灵活调整飞行姿态的问题,设计了一款可变幅扑翼飞行器,通过调节翅翼扑动幅值,实现扑翼运动姿态和飞行模式切换.建立可变幅扑翼飞行器机构运动学模型,基于Adams和Matlab进行联合仿真,对扑翼飞行器进行运动特性分析.建立多飞行模式下的气动模型,通过XFLR5软件分析可变幅扑翼飞行器的气动特性,通过设定相关参数,实现了起飞、快速飞行、慢速巡航等多种飞行模式,提高了扑翼飞行器的灵活性,为未来扑翼飞行器的进一步发展提供了研究基础.     

微扑翼飞行器总体设计及实验

提出了适合工程实际的微扑翼飞行器的设计方法.利用几何相似原理,拟合了以翼展为基本参数的仿生公式,并确定了飞行参数、结构参数和动力参数.根据初步的仿生设计结果,进行传动结构、翅翼尾翼等总体结构设计,并按照运动学分析、气动力分析、动力学分析相结合的动态分析方法研究了扑翼样机理论上产生的升力.与风洞实验结果比较表明,平均升力误差为0.61 g,基本满足设计要求,为微扑翼飞行器的研制提供了理论和实验依据.     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.