无刷直流电动机的神经网络PID控制器研究

提出了一种基于BP神经网络的PID控制器,该控制器有机结合了BP神经网络和PID的特点,克服传统PID控制存在的不足,并采用快速BP算法改善其收敛性,有效的提高了无刷直流电动机调速系统性能,仿真研究表明上述神经网络PID控制器,比传统PID控制器控制动态过程有明显改善,能够获得更高的跟踪精度。     

基于改进型BP神经网络PID控制器在转台系统中的应用研究

为改善转台系统性能,针对传统的PID控制参数难以获得较理想的控制效果,设计了一种基于改进型BP神经网络的PID控制器。介绍了PID控制器的结构和BP神经网络算法描述,利用最小二乘法和神经网络建立被控对象的预测数学模型,并用该模型所计算的预测输出取代预测输出的实测值,对基于BP网络的PID控制器的权值调整算法进行改进。以某转台模型为对象,建立了转台控制系统的数学模型并对其进行仿真。仿真结果表明,改进型BP神经网络PID控制器具有良好的控制效果,跟踪精度高、性能稳定及鲁棒性强,能更为有效地应用到转台系统中。     

基于BP神经网络的电动伺服加载算法研究

该文从加载控制器角度出发将BP神经网络算法引入加载系统削弱多余力矩对系统的影响,提高加载精度。建立了电动伺服加载系统的数学模型,分析了多余力矩产生的原因以及基于结构不变原理存在的局限性。介绍了BP神经网络控制算法基本原理,并给出了具体控制结构及相应算法,设计了一种BP/PID复合控制器。仿真结果表明,复合控制器有效地抑制了系统的多余力矩,降低跟踪误差,改善加载系统的动态性能,提高了跟踪精度,增强了稳定性。     

基于BP神经网络的料筒温度PID控制器

针对注塑机料筒温度控制的要求和PID控制器的不足,设计了一种基于BP神经网络的PID控制器.该控制器将神经网络和PID控制技术相结合,能无限地逼近非线性系统,具有收敛快的优点.提出了基于BP神经网络的PID控制算法和程序流程.仿真结果表明,BP神经网络PID控制器能有效地缩短过渡过程,具有较好的稳定性和快速响应性,可以满足注塑机料筒的温度控制要求.     

基于BP-PID的数控机床进给伺服系统控制仿真分析

在智能制造领域,数控机床最终加工出来的产品质量除了与机床本身性能有关外更重要的是进给系统的伺服优化效果。为提高数控机床进给伺服系统优化效果,设计了一种基于BP神经网对数控机床进给系统PID控制器进行优化的模型。利用BP神经网络具有逼近任意非线性函数的特点,通过对系统性能优化算法实现最佳PID参数组合。Matlab/Simulik仿真实验结果表明,BP-PID控制器能够快速、有效地对非线性数控机床进给系统进行控制,对提高机床加工精度具有重要意义。     

基于遗传算法的模糊神经网络控制器在烘干炉温度控制系统中的设计与仿真

以烘干炉温度为被控对象,由于烘干炉温度控制具有非线性、大滞后和无法建立精确数学模型等特点,传统的控制器很难达到理想的控制效果,为此设计了一种基于遗传算法的模糊神经网络控制器.基于遗传算法的模糊神经网络控制器是将遗传算法的全局寻优和BP算法的在线学习结合起来,先用遗传算法对神经网络的参数进行离线训练,然后再用BP算法对模糊神经网络控制器进一步在线学习.仿真结果表明,基于遗传算法的模糊神经网络控制器与模糊控制、传统PID控制相比较,改善了系统的动态性能和静态性能,能使非线性、大滞后等特殊的系统达到良好的控制效果.     

基于神经网络内模的电加热炉温度控制研究

针对加热炉温度控制中存在的非线性、大滞后问题,以实验室电加热为对象,提出了一种基于BP神经网络的内模控制方法,即用神经网络对复杂系统的辨识能力来实现内模控制中被控对象的正模型及内模控制器.仿真结果表明,该控制方法控制效果良好,与PID控制系统相比具有较强的鲁棒性,从而为加热炉的控制问题提出了一种新的方法.     

基于改进粒子群算法的神经网络PID控制研究

BP神经网络PID控制是利用BP神经网络的自学习和逼近任意非线性函数功能,对PID控制器的三个参数进行在线整定,但网络初始权值的选取困难.采用改进的PSO算法优化BP神经网络的初始权值,并对基于PAO算法的BP神经网络PID控制进行仿真实验.仿真结果表明,PSO算法使得网络初始权值的选取比较快速,系统的性能有所提高.     

基于BP网络的气动人工肌肉位置跟踪的研究

用BP神经网络对单支气动人工肌肉系统进行了阶跃信号及正弦波位置跟踪的研究，实验证明，运用BP神经网络PID控制器，与PID及神经网络控制器相比，有较好的跟踪效果。     

基于模糊神经网络的磁浮车悬浮控制器

以EMS型磁悬浮车单电磁铁为研究对象,建立了系统的数学模型.为增强悬浮系统的抗干扰能力和负载能力,针对其非线性特性,采用神经网络和模糊控制理论相结合的方法设计了非线性控制器FNNC.该控制器继承了模糊控制鲁棒性强以及神经网络的非线性逼近和自学习能力,运用加速反传训练方法对参数进行调整,并通过TMS320F2812型DSP实现单点悬浮用.实验及仿真表明,该控制器使系统悬浮稳定,动态性能好,与传统的PID控制器相比具有更好的快速跟踪性能和抗干扰能力.     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.