基于生物激励神经动力学的AGV轨迹跟踪控制

提出了一种基于门限偶极子生物神经元模型和快速终端滑模控制策略的轨迹跟踪控制算法,使AGV在存在初始速度跳变的情况下能顺利实现小车的轨迹跟踪控制。首先由运动学控制器产生一个理想控制律,接着利用神经动力学思想解决初始速度跳变问题,最后用快速终端滑模控制器进一步提高跟踪精度。该控制器的输出有界且光滑,整个控制系统全局快速渐进稳定。计算机仿真结果验证了该控制器的有效性。     

自主导航小车(AGV)轨迹跟踪的模糊预测控制

针对非完整约束的轮式移动机器人WMR轨迹跟踪问题,以差速驱动式轮式移动机器人XAUT.AGV100为研究对象,对WMR的运动控制问题作了进一步的研究。本文在分析现有移动机器人运动控制方法的基础上,充分利用模糊控制和预测控制的优点,将模糊控制的思想引入到预测控制中,设计了模糊预测控制算法,并采用此方法控制自主导航小车AGV以提高其轨迹跟踪的快速性和运动的平稳性。理论仿真分析和实验研究均证明,采用所设计的模糊预测方法控制AGV,可有效提高AGV轨迹跟踪的快速性和运动平衡性。     

基于参考轨迹的移动机器人避碰决策及轨迹跟踪方法

针对车间物流移动机器人轨迹跟踪的鲁棒控制问题，提出一种基于参考轨迹信息的避碰决策及轨迹跟踪控制方法。首先，基于参考轨迹全局信息构建了避碰触发条件，较现有的基于当前相对位置和相对速度信息的避碰条件更为精准，避免非必要的避碰动作；然后，综合考虑参考轨迹全局信息和避碰触发条件，设计了考虑避碰约束的移动机器人模型预测轨迹跟踪控制算法。仿真结果表明，本文所提方法在时间扰动和位置扰动下具有良好的避碰与轨迹跟踪性能，可实现多种场景下多移动机器人的鲁棒轨迹跟踪控制。     

轮式移动机器人轨迹跟踪控制研究

根据轮式移动机器人具有非完整约束特点,基于其运动学模型对机器人的轨迹跟踪控制问题进行了研究。采用Lyapunov函数直接法的思想设计机器人轨迹跟踪控制算法,并且直观地分析了系统的全局渐进稳定性.最后应用到MATLAB中对圆轨迹、螺旋线轨迹进行跟踪仿真试验,仿真结果表明位姿误差在2 s时刻趋近于零,轨迹跟踪效果良好,系统具有很好的全局渐进稳定性。     

基于滑动动力学模型的机器人轨迹跟踪控制

针对三轮全向移动机器人在运动过程中产生的滑动现象,提出一种基于滑动动力学模型的轨迹跟踪控制方法。在三轮全向移动机器人运动学以及动力学建模的基础上,通过分析轮毂滚动方向和滚子滚动方向上的车轮接触摩擦力,提出了一种滑动动力学模型,并将该模型引入三轮全向移动机器人闭环运动控制系统,以提高其轨迹跟踪控制精度。在Matlab/Simulink平台上进行轨迹跟踪控制仿真。结果表明,基于滑动动力学模型的三轮全向移动机器人运动控制系统具有较好的稳定性和准确性。     

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。     

移动机器人路径跟踪控制方法研究

基于两轮差动驱动的移动机器人,设计了一种路径跟踪控制系统。系统采用临时路径生成方法,通过规划移动机器人跟踪上期望路径前的轨迹,消除初始位置误差和方向误差,解决了移动机器人直接跟踪期望路径时控制量可能过载的问题,使机器人光滑趋近到期望路径。控制器的设计采用模糊控制器。试验验证了系统的有效性。     

滑移扰动下轮式移动机器人神经滑模跟踪控制研究

针对轮式移动机器人在滑移扰动下模型的不确定性,提出了一种基于RBF神经滑模控制的跟踪控制策略。建立机器人在滑移扰动下的动力学模型,利用运动学反步控制器得到虚拟线速度和角速度,基于虚拟输入设计了神经滑模动力学控制器,最后对所设计的控制器进行仿真与实验,结果表明该控制方法能快速准确地在滑移扰动下跟踪期望轨迹,具有良好的误差收敛效果。     

基于径向基神经网络图像识别的移动机器人控制系统仿真

为实现人机交互的移动机器人轨迹控制,研究了基于径向基神经网络图像识别的移动机器人控制系统,设计了基于神经网络的图像采集和识别处理模块,处理了移动机器人路径控制的关键问题。通过建立手写字体数字(基于神经网络)的图像采集和识别处理模块,搭建移动机器人轨迹控制数学模型,最终在该模型基础上设计了该类机器人基于图像识别结果的路径控制算法。利用仿真软件MATLAB的robot tool工具箱,进行了移动机器人控制轨迹控制的仿真。仿真结果证明,路径控制方案可以很好的让移动机器人完成预定的路径跟踪。从而从理论上解决了基于视觉的移动机器人轨迹控制问题的难题,并为实现基于视觉的移动机器人轨迹控制提供了理论依据。     

变论域模糊补偿的机械臂积分终端滑模控制

为了减小机械臂在环境扰动、参数漂移和建模误差等影响下的轨迹跟踪误差,设计了基于积分终端滑模和变论域模糊补偿的组合控制器。采用拉格朗日方程建立了机械臂系统的动力学模型,制定了不确定因素影响下机械臂跟踪控制方案;设计的积分终端滑模控制器可以将系统初始状态限制在滑模面上,消除了控制过程的抖振并提高了跟踪速度;提出了自适应论域策略,该策略可以提高补偿力矩的输出细粒度,并将变论域模糊算法用于不确定因素补偿。经实验验证,变论域模糊补偿控制对关节1角位置的最大跟踪误差为0.103 rad,误差绝对均值为0.025 rad,对关节2角位置的最大跟踪误差为0.073 rad,误差绝对均值为0.012 rad,跟踪控制精度高于模糊补偿控制、RBF-BP控制和自适应鲁棒控制,验证了变论域模糊补偿控制方法的有效性和先进性。     

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.