航空遥感惯性稳定平台模糊/PID复合控制

为提高航空遥感惯性稳定平台控制系统稳定精度和扰动抑制能力,在常规PID控制的基础上设计了一种模糊控制与PID相结合的复合控制算法,分别应用于稳定平台横滚框及俯仰框系统进行实验验证。在三环控制系统位置环中将模糊控制与PID控制方法结合使用,并引入变论域思想,建立模糊/PID复合控制器,满足输出偏差变化不同时刻对PID参数整定的要求。通过模糊控制器实时调整PID参数,使系统具有良好的动、静态特性,实现多源扰动下惯性稳定平台的高稳定精度控制。分别通过仿真和静动态实验对方法进行分析和验证。实验结果表明:与常规PID控制及单纯模糊控制相比,模糊/PID复合控制器具有优越的扰动抑制能力和高稳定精度。相对传统PID控制,横滚框和俯仰框的静态均方根误差(RMS)值分别下降51%和73%、动态RMS值分别下降约20%和30%。     

惯性稳定平台变置信度优化平滑CMAC复合控制

提出了一种基于变置信度(MC)及优化平滑算法(OS)的改进型小脑模型关节控制器(CMAC)复合控制方法,用于提高航空遥感惯性稳定平台控制系统指向精度及稳定性。首先,以CMAC学习过程中存储单元被激活的次数为依据,对存储单元设置不同的置信程度,提高了CMAC控制器的学习效率与控制精度,避免了系统动态跟踪中过学习发散现象而导致的控制系统精度下降甚至崩溃;其次,针对常规CMAC算法系统输出波动较大问题,加入优化权值算法,改善系统输出平滑性,提高了CMAC控制器的稳定性,避免了系统输出波动对电机及传动系统损害;最后对提出方法进行了仿真分析并利用实验室某三轴惯性稳定平台进行实验验证。实验结果表明:采用基于MCOS的改进型CMAC复合控制方法后,稳定平台系统控制精度、响应速度及输出平滑稳定性均得到有效提高,动基座推车实验框架角位置水平跟踪误差RMS值为0.021 6°,相对PID与常规CMAC控制方法分别降低了55.09%和30.55%。     

改进算法单神经元PID在飞轮储能系统中的研究

PID控制器是在工业中应用最为广泛的控制技术,然在而其三个参数的调节较复杂烦琐.通过对神经网络自适应特性的研究,设计了改进算法的单神经元PID控制器,利用单神经元自学习能力在线调整PID参数;同时结合自适应PSD算法对神经元增益在线调整.将该控制器应用于飞轮储能系统中,结合SVPWM算法对飞轮电池进行充放电控制.实验仿真结果表明,该控制方法能够使飞轮电池充放电过程快速稳定,鲁棒性强,满足实际控制要求.     

变频泵控马达调速系统单神经元自适应PID控制

针对大惯性负截变频泵控马达调速系统动态性能差的特点，提出了采用不必基于模型的单神经元自适应PID控制。介绍了单神经元自适应PID控制器的结构和算法。仿真结果表明，单神经元自适应PID控制器较常规PID控制器具有更快的响应特性和良好的动态特性，对模型失配和负载扰动表现出更强的适应性和鲁棒性，而且不论是在加速段、等速段还是减速段，都具有较好的跟踪效果。     

硅基集成式微型平面纳米级定位平台控制

为了解决纳米级定位平台小型化、低能耗、定位精度高的问题,基于结构、驱动和检测一体化的设计理念,研制出了一种硅基片上集成式微型平面纳米级XY定位平台,在建立定位平台数学模型基础上,利用Matlab分析软件对定位平台开环和闭环控制特性进行了比较和仿真分析.在实际控制中,针对硅微机械加工的MEMS器件难以获取精确数学模型的不足,将单神经元算法和传统PID控制算法相结合,设计了具有自动识别被控过程参数并对控制参数进行实时自校正的单神经元自适应PID控制器,依靠平台自身集成的位移传感器实现了定位平台的位置闭环控制,实验结果表明:单神经元自适应PID控制器不仅具有结构简单、鲁棒性好等特点而且能够有效地弥补硅基定位平台由于微机械加工限制造成的机构方面不足,定位平台的动态和稳态性能良好,最大工作行程±10 μm,稳定时间小于2.5 ms,重复定位精度优于24.9 nm.     

钢坯闪光焊接的单神经元复合控制及其电液联合仿真

该文根据复合控制器的设计原理,应用自适应神经元提出了一种基于单神经元的复合控制方案;使用工程仿真软件AMEsim建立了钢坯闪光焊接的非线性液压系统模型,通过与控制系统接口实现了电液联合仿真;仿真结果表明设计的单神经元复合控制器的控制效果明显优于传统方法设计的复合控制器。     

改进粒子群算法在主动磁悬浮轴承系统中的应用

通过分析得知,主动磁悬浮轴承系统本身是一个不稳定系统,可以采用PID控制器对其进行控制。但是传统PID控制在主动磁悬浮轴承系统中还存在着不足之处,为此可以将粒子群优化算法与常规PID控制相结合,对PID控制器中的参数进行优化,使系统能够达到更好的控制效果。采用了一种改进粒子群算法,对算法中的惯性权重w进行自适应调节,从而使得算法能够更快、更准确地寻找到最优值。通过Matlab/Simulink构建系统模型并进行仿真对比,改进粒子群算法可以使得系统达到更好的控制效果。     

基于干扰补偿的稳定平台控制系统设计

为克服机电伺服系统的摩擦以及其它力矩干扰问题,提出一种基于LuGre模型的摩擦前馈补偿和基于扰动观测器反馈补偿的复合控制策略。以某型号惯性稳定平台的单轴转台为例,首先对单轴转台进行建模分析,根据不变性原理,设计摩擦前馈补偿控制,再根据观测器输入和输出之间存在的数学关系,利用陀螺反馈的角速度信号,设计了基于扰动观测器的力矩补偿控制,最后在试验平台上,采用位置环为离散增量式PID算法,速度环为抗积分饱和PI算法,对提出的复合控制方法进行验证分析。稳定平台的实验结果表明所设计的惯性稳定平台控制系统能有效地抑制机电伺服系统中的摩擦及其它力矩干扰因素,一定程度上提高了惯性稳定平台的稳定性和动态跟踪性能。     

凿岩机械与气动工具

GJ20042159 单神经元自适应 PID 算法在气动人工肌肉位置控制中的应用研究[刊,中]/高建英…∥液压与气动.—2004,(1).—18～20 文章以单支气动人工肌肉为研究对象,分别构造了 PID 控制器及单元神经元自适应 PID 控制器进行位置控制。实验证明:运用单神经元自适     

基于改进PSO算法整定PID参数的设计与研究

比例-积分-微分（Proportion-Integral-Differential,PID）控制设计简单、工作原理易掌握、调整参数少,多应用于工业自动控制领域。针对传统参数整定方法时间长、精确度低等问题,提出基于惯性权重自适应粒子群优化（Particle Swarm Optimization,PSO）算法快速整定PID参数的方法,在验证改进算法可行性的基础上,以二阶延迟系统为被控对象进行仿真实验。实验结果表明,利用PSO算法优化后的PID控制器,在系统的控制上拥有更好的控制效果,提高了系统的稳定性。     

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。     

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.     

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....     

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.