考虑打滑干扰的解耦式主动脚轮全向移动机器人跟踪控制

基于解耦式主动脚轮的全向移动机器人系统,提出了一种考虑未知脚轮打滑的轨迹跟踪控制方法。建立了包含脚轮打滑情况的全向移动机器人运动学模型,利用附加传感器获得的冗余信息对滑动参数进行估计;根据反步法设计轨迹跟踪控制器,利用Lyapunov定理证明闭环系统的稳定性,并依据极点配置的方法实现控制参数的整定。仿真与实验结果表明：该控制方法能够使全向移动机器人在复杂室内地面稳定地跟踪设定轨迹。     

基于LQR的单球自平衡移动机器人控制器设计与仿真

针对单球自平衡移动机器人的非线性、高度耦合性和不稳定特性,提出了一种基于LQR的控制器。首先将其三维复杂动力学模型简化为三个独立平面的二维动力学模型,并建立拉格朗日平面动力学方程;其次根据平面动力学方程设计LQR控制器并在Sim ulink中建立控制系统仿真模型;最后对控制系统模型进行直线轨迹和圆弧轨迹跟踪仿真。仿真结果表明该控制器对线性轨迹和非线性轨迹都有很好的跟踪效果。     

基于控制Lyapunov函数的履带式移动机器人轨迹跟踪

将履带式移动机器人简化为轮式移动机器人系统,建立了其运动模型.讨论了基于运动模型的履带式移动机器人的轨迹跟踪问题.在此基础上,基于控制Lyapunov函数,设计了履带式移动机器人的轨迹跟踪控制器.考虑到机器人的运动学约束,引入受限策略以保证其运动平滑.仿真结果验证了所设计控制器的有效性和正确性.     

基于光学动作捕捉的室内移动机器人轨迹跟踪

以基于麦克纳姆轮的全向移动机器人为研究对象,首先对基于标记点的光学动作捕捉系统的定位原理进行研究,然后对移动机器人的驱动原理和位姿误差进行分析,建立运动学模型和位姿误差模型,通过反演法设计虚拟反馈,并结合李雅普诺夫函数构造出具有全局渐近稳定的轨迹跟踪控制器。接着对测试环境和试验样机进行搭建,将光学动作捕捉系统采集的位姿信息反馈到机器人的控制回路中,最后对直线和圆周轨迹进行跟踪仿真。通过在试验样机上实验验证,总结出利用光学动作捕捉系统对移动机器人采集的定位信息,可令移动机器人拥有良好的轨迹跟踪性能。     

基于自适应滑模控制的四轮全向移动机器人轨迹跟踪方法研究

针对四轮全向移动机器人动力学模型参数的不确定性以及外部扰动的影响,为提高其轨迹跟踪控制性能,提出了一种基于自适应滑模的四轮全向移动机器人轨迹跟踪控制方法。首先,基于驱动电机参数建立了机器人的动力学模型,在此基础上设计了一种自适应滑模轨迹跟踪控制器;其次,通过低通滤波器滤除轨迹跟踪控制器输出端的高频信号,同时为实现机器人动力学参数的在线估计,提出了一种参数自适应控制算法并利用RBF神经网络实时调整轨迹跟踪控制器的切换增益,以减小系统的抖振;最后,为验证所述方法的有效性,采用MATLAB进行了仿真实验。仿真结果表明,基于自适应滑模控制的四轮全向移动机器人轨迹跟踪方法可以较好地降低参数变化、外部扰动对系统的影响,能够减小系统的抖振,具有较好的抗干扰能力。     

非完整移动机器人的自适应全局轨迹跟踪控制

针对含有未知参数的移动机器人运动学模型,利用自适应反演控制技术,讨论了两后轮角速度为控制输入的非完整移动机器人轨迹跟踪问题,构造了具有全局渐近稳定性的自适应轨迹跟踪控制器,该方法将系统分解为低阶子系统来处理,利用中间虚拟控制量和部分Lyapunov函数简化了控制器的设计并具有直观的稳定性分析。仿真结果验证了所设计控制器的有效性和正确性。     

非协调移动机器人的变结构跟踪控制

研究非协调移动机器人系统的跟踪问题。根据反演设计的方法 ,针对双后轮驱动移动机器人的运动学模型 ,设计变结构跟踪控制方案 ,使闭环跟踪系统渐近稳定。对双后轮驱动机器人的仿真证实了控制器的鲁棒跟踪能力     

两轮差动球形移动机器人轨迹跟踪控制（英文）

针对现有球形机器人运动难以控制以及球壳限制传感器应用的问题,提出了一种双轮差动式球形移动机器人,其结构简单、运动灵活且易于控制。首先,根据球形移动机器人结构,建立了运动学与动力学模型。然后,基于自适应神经滑膜控制方法,设计了该系统的轨迹跟踪控制器。最后,通过对球形机器人进行S轨迹和圆周轨迹的跟踪控制仿真,得出了球形移动机器人具备灵活地运动特性且易于控制的结论。仿真结果验证了自适应神经滑模控制能够有效地对球形机器人进行轨迹跟踪,自适应控制消除了系统未知参数与扰动的影响,同时也避免了左右轮力矩输出的抖振问题。     

基于差分进化遗传优化的移动机器人轨迹跟踪控制

为了提高轮式移动机器人的轨迹跟踪精度,提出了一种基于差分进化遗传优化的轮式移动机器人轨迹跟踪控制器。首先,针对四轮机器人建立了运动学模型;接着,以移动机器人的侧向距离和航向偏角作为控制变量,构建了机器人的轨迹跟踪PID控制器;最后,利用差分进化遗传算法实现了控制器参数的整定优化。轨迹跟踪测试结果表明,与其他控制器相比,基于差分进化遗传优化的控制器的控制精度得到了进一步提高,从而验证了控制器的有效性。     

履带式移动机器人轨迹跟踪控制技术研究

随着移动机器人在工业、农业、军事等领域中的广泛应用,对其自主运动控制技术的需求逐渐增大.为了实现履带式移动机器人的轨迹跟踪控制,建立了运动学模型和轨迹跟踪动态误差模型.基于Lyapunov稳定性理论,提出了一种状态反馈控制律,并通过Lyapunov函数对控制律的稳定性进行了证明.为了评估所提出控制律的性能,在Matlab/Simulink环境下分别进行了直线轨迹跟踪和圆形轨迹跟踪仿真实验.仿真实验结果表明,所设计的控制律能够快速有效地实现直线轨迹跟踪与圆形轨迹跟踪,具有较好的控制效果,可应用于履带式移动机器人轨迹跟踪控制的实际项目中.     

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.     

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。     

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....     

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.