填料塔热交换系统的模糊模型PID优化控制

建立了填料塔热交换实验装置的计算机控制系统.针对过程的严重非线性与不稳定性,在机理分析的基础上建立了分段非线性模型,提出了一种基于T-S模糊模型的非线性系统PID优化控制算法,设计了该装置的模糊模型PID优化控制器.实验结果与传统的PID控制结果进行对比表明,采用模糊模型PID优化控制方法能够有效解决非线性控制问题,控制效果令人满意.     

基于ADAMS和MATLAB的双回路PID控制倒立摆联合仿真

倒立摆系统是典型的快速、多变量、非线性、绝对不稳定系统,是检验各种控制理论的理想模型。研究了倒立摆系统的构成并建立了数学模型,针对摆杆角度和小车位移两个输出量采用双回路PID控制并设计了PID控制器,在ADAMS软件中建立了倒立摆系统的机械模型,在MATLAB软件中建立了控制模型,通过接口实现了双回路PID控制倒立摆的联合仿真。文中方法直接从ADAMS中产生机械系统仿真模型,避免了推导、列写较复杂的方程描述机械系统,大大简化了建模过程,而且能够更直观地观察仿真结果。     

对含分数阶阻尼器非线性悬架的PID控制研究

对由分数阶磁流变阻尼器(分数阶Bingham模型)和非线性弹簧组成的汽车悬架系统进行PID控制研究,先建立其二自由度非线性悬架数学模型,再根据车辆的舒适性和平顺性要求设计PID控制器,在Matlab/simulink中建立非线性悬架的仿真模型,对PID控制器参数整定,并用Oustaloup逼近算法解算分数阶微积分因子,实现数值仿真。结果表明,该悬架与被动悬架相比,该悬架的平顺性和舒适性有明显的提高,说明在既含有分数阻尼器又含有非线性弹簧时,以PID控制器对悬架进行控制同样有效,对以后研究非线性悬架有一定的指导意义。     

基于联合仿真的电液系统模糊PID控制研究

针对电液伺服系统的非线性、扰动、参数时变的特点,采用模糊PID策略改善控制品质,并用联合仿真代替传统的传递函数建立模型。研究表明:联合仿真模型更接近实际系统,模糊PID控制在快速性、动态跟踪品质、抗绕动性和控制精度等方面均具有良好的性能。     

科氏流量计驱动系统模糊PID控制器设计及仿真

针对科氏流量计驱动系统具有非线性和时变性的特点,为改善对测量管振动的控制,采用模糊PID控制策略设计了驱动增益模糊PID控制器,并利用MATLAB中的Fuzzy Logic Toolbox和Simulink工具建立了驱动系统仿真模型,分别采用常规PID控制和模糊PID控制进行了仿真试验和比较,结果表明模糊PID控制提高了系统的起振性能和追踪测量管振幅变化的能力,具有较好的综合控制性能.     

一种基于模糊PID的工业锅炉温度控制系统设计

本文针对工业生产中温度控制系统具有非线性、时变性和滞后性的特点,采用模糊控制与PID相结合的方法,设计了一个基于模糊PID的工业锅炉温度控制系统,采用AT91RM9200为主控制芯片,并用模糊PID控制算法对温度进行控制.最后以工业锅炉蒸汽温度为被控对象,建立仿真模型对常规PID控制和模糊PID控制进行了仿真对比,结果表明采用模糊PID控制方法,有效的提高了系统对非线性、时变性和不确定性的处理能力,控制效果更好.     

基于模糊PID算法的气动软体驱动器控制策略研究

气动软体驱动器的材料与电气比例阀的压力控制都具有较强的非线性,传统的PID控制方法对非线性系统的控制很难达到理想的效果。文中提出了一种将模糊控制与PID相结合的控制策略。根据电气比例阀结构与工作原理,初步建立了电气比例阀的数学模型。通过基于采集输入输出数据的系统辨识方法来获得控制系统的传递函数,基于此传递函数在MATLAB/Simulink中建立模糊PID控制模型并对其进行仿真,将模糊PID和PID的控制效果进行比较。结果表明,模糊PID算法在电气比例阀压力输出控制方面具有更好的自适应能力。     

电动汽车无刷直流电机的改进模糊控制研究

通过对永磁无刷直流电机数学模型的分析,提出一种基于遗传算法优化的模糊PID控制方法。并结合整车动力学模型用MATLAB/Simulink建立了采用该方法的电机仿真模型。分别对使用传统PID、模糊PID和遗传算法优化后的模糊PID的永磁无刷直流电机控制系统进行仿真。仿真结果表明所提控制方法具有较好控制效果,能够更好适应车辆频繁加减速等复杂运行工况。     

桥式起重机定位和消摆的非线性优化PID控制研究

为了提高桥式起重机有效防摆、快速消摆的能力和工作效率,以桥式起重机的定位和消摆控制为研究对象,在分析了桥式起重机小车运行物理模型的基础上,根据拉格朗日方程建立了桥式起重机运动的非线性数学模型。针对桥式起重机模型的非线性和不确定性,提出了一种基于非线性优化PID控制器的桥式起重机消摆控制方法。该方法采用基于非线性优化双闭环结构PID控制器,其内环为摆角环实现消摆,外环为位置环实现位置准停。由仿真结果可知,基于非线性优化PID控制器可以在位置很小的超调下迅速达到指定位置,同时消除摆动,较好的实现了控制目标。与常规PID控制器相比,位置环和摆角环非线性优化PID控制器取得了较好的消摆效果,响应速度快,稳态精度更高,并且当吊重质量和绳长发生改变时,系统仍有较强的鲁棒性。     

基于MATLAB的直流无刷电机模糊PID控制设计

针对直流无刷电机控制性能指标复杂的特点,文中在智能控制技术方面着重以模糊PID控制技术进行研究,探索了电机控制系统动态性能指标的优化控制方法。按照控制原理对电机控制系统进行系统设计,确定了直流无刷电机模型;基于模糊PID控制原理进行系统控制器设计,针对各项PID参数进行求解;开展了基于MATLAB的设计研究与模糊PID系统仿真。通过系统对比设计,相较传统PID,运用模糊PID对非线性被控对象进行控制,得到了更好的稳定性以及鲁棒性。     

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.