磁粉制动器数学建模与控制方法研究

为了提高磁粉制动器的加载质量,在建立其数学模型的基础上,对相应的控制算法进行了研究。由于磁粉的滞后性,提出了施密斯预估控制的方式,但施密斯预估控制对系统的数学模型有较高的要求,故引入模糊控制的控制方式,构成模糊施密斯控制,并在此基础上提出了对模糊施密斯控制的输出进行积分作用,从而达到理想的控制效果。利用Matlab,实现了常规PID控制和引入积分的模糊施密斯预估控制对磁粉制动器控制的计算机仿真,仿真结果表明:引入积分作用的模糊施密斯预估控制对磁粉制动器这类时滞系统来说,较常规PID控制而言,具有更高的实用性。     

基于模糊自适应PID控制算法的螺栓扳手扭矩控制系统设计

针对传统机械扳手在扭矩控制方面存在的精度低、稳定性较差等问题,设计了一种基于模糊自适应PID控制算法的螺栓扳手扭矩控制系统.该控制系统外环采用模糊自适应PID控制器作为转速环调节器,内环采用传统PID控制器控制电流,使用电流传感器和霍尔转速传感器采集电机转动过程中的电流和转速,并使用滑动加权平均滤波算法消除随机干扰噪声以提高采集精度,实现对扭矩的精确控制.实验结果表明:模糊自适应PID控制算法拥有良好的动态性能和较强的鲁棒性,同时在1 200～3 000 N·m扭矩范围内,该控制系统的扭矩控制相对误差最高为3.67％,最低为1.50％,且运行稳定、可靠,具有很高的实用价值和推广价值.     

基于模糊自适应PID控制算法的螺栓扳手扭矩控制系统设计

针对传统机械扳手在扭矩控制方面存在的精度低、稳定性较差等问题,设计了一种基于模糊自适应PID控制算法的螺栓扳手扭矩控制系统.该控制系统外环采用模糊自适应PID控制器作为转速环调节器,内环采用传统PID控制器控制电流,使用电流传感器和霍尔转速传感器采集电机转动过程中的电流和转速,并使用滑动加权平均滤波算法消除随机干扰噪声以提高采集精度,实现对扭矩的精确控制.实验结果表明:模糊自适应PID控制算法拥有良好的动态性能和较强的鲁棒性,同时在1 200～3 000 N·m扭矩范围内,该控制系统的扭矩控制相对误差最高为3.67％,最低为1.50％,且运行稳定、可靠,具有很高的实用价值和推广价值.     

基于STM32的直流电机模糊PID调速系统研究

针对普通PID控制难以满足现代工业对直流电机控制高速度、高精度要求的问题,对直流电机及其控制系统进行了研究,设计了一种以STM32芯片为核心的自适应模糊PID控制直流电机调速系统。此调速系统通过采用模糊自适应PID控制算法改变PWM波占空比来实现系统灵活调速。在实验环境中,分别采用普通PID控制器和参数自适应模糊PID控制器来实现直流电机的调速系统,并通过主控芯片实时发送电机速度到上位机软件,绘制响应曲线。研究结果表明,模糊PID控制器在电机运行过程中,系统动态调节直流电机的PID参数,有效解决了传统PID整定困难的问题,并显著提高了电机的响应速度和控制精度。     

基于模糊自适应PID控制算法的螺栓扳手扭矩控制系统设计

针对传统机械扳手在扭矩控制方面存在的精度低、稳定性较差等问题,设计了一种基于模糊自适应PID控制算法的螺栓扳手扭矩控制系统.该控制系统外环采用模糊自适应PID控制器作为转速环调节器,内环采用传统PID控制器控制电流,使用电流传感器和霍尔转速传感器采集电机转动过程中的电流和转速,并使用滑动加权平均滤波算法消除随机干扰噪声以提高采集精度,实现对扭矩的精确控制.实验结果表明:模糊自适应PID控制算法拥有良好的动态性能和较强的鲁棒性,同时在1 200～3 000 N·m扭矩范围内,该控制系统的扭矩控制相对误差最高为3.67％,最低为1.50％,且运行稳定、可靠,具有很高的实用价值和推广价值.     

基于电液比例阀控缸位置系统控制策略的研究

对电液比例阀控缸位置系统的模糊自适应PID控制器进行设计与研究。通过实验对模糊自整应PID控制与经典PID控制在正弦信号的跟踪精度与稳定性方面进行比较,实验结果表明模糊自整应PID控制器相较于传统PID控制是一种性能更加优异的控制器,可以广泛应用于工业控制领域。     

数控机床进给伺服系统模糊自适应PID仿真

针对传统的PID控制策略不能满足数控进给伺服系统的对控制性能要求。结合模糊控制理论,在传统PID控制基础上设计出一种基于模糊决策的模糊自适应PID控制器。运用模糊控制理论,对PID参数进行实时修改,使系统具有较好的自适应能力和较强的鲁棒性。在MATLAB环境下对进给伺服系统进行了动态仿真;仿真结果表明,模糊自适应PID控制器的控制性能远优于常规PID控制器,即使在外界干扰和系统工况发生变化时,此控制器也具有很好的快速响应特性和较强的鲁棒性。     

基于PLC的镀槽温度控制系统设计

为了实时对镀槽温度进行监控,并有效控制镀槽温度精度,设计了一种基于PLC的镀槽温度控制系统。首先介绍了镀槽温度控制系统硬件结构,为了克服传统PID控制方法的缺陷,在PID控制中引入了模糊控制理论,从而提高了系统的自适应能力。最后对模糊PID控制器进行了仿真分析。仿真结果表明,该模糊PID控制器响应速度快、超调量小,能够实现镀槽温度的精确控制。     

基于MATLAB的电液伺服系统模糊PID控制研究

在MATLAB/Simulink环境下,针对某火箭炮方向机电液伺服系统,设计了模糊自适应PID控制器和常规PID控制器,并分别对该系统进行仿真,研究系统的动态响应性能。仿真研究表明:自适应PID控制器结合了PID控制器高精度和模糊控制器控制快速、适应性强的特点,并且改善了控制系统的动态性能,提高了系统的控制精度。在此基础上分析了一些参数的变化对液压系统性能的影响,为系统的进一步优化设计提供了理论依据。     

模糊PID控制在铝包钢感应加热温控系统的应用

为了实现对铝包钢丝温度的在线控制,采用自适应模糊PID方法研究感应加热过程中的温度控制问题。利用自适应模糊控制器在线调整PID控制器的3个参数,实现了模糊智能控制技术与PID常规控制的结合,控制器根据当前温度与设定温度值的差值和差值变化率来实时调整PID参数的变化量。利用MATLAB的Simulink工具箱对控制器进行了设计和仿真,仿真结果表明,这种自适应模糊PID控制器既具有模糊控制灵活、响应快、适应性强等优点,又具有PID控制精度高的特点,改善了铝包钢感应加热系统温度的控制效果。     

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...     

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.     

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.     

Fractional order nonsingular terminal sliding mode control for flexible spacecraft attitude tracking

This paper investigates a fractional terminal sliding mode control for flexible spacecraft attitude tracking in the presence of inertia uncertainties and extern...     

奥氏体不锈钢表面双辉等离子渗锆的动力学

利用双辉等离子渗金属技术在0Cr18Ni9Ti奥氏体不锈钢表面制备了一层均匀、致密、呈良好冶金结合的渗锆合金层,并对1 060℃下的渗锆动力学进行了研究。结果表明:随着距锆合金层表面距离的增加,锆元素的含量呈梯度递减,扩散系数逐渐减小,而扩散激活能逐步增大;在1 060℃采用双辉等离子技术渗锆时,渗锆合金层表层的空位密度为2.945×(1012~1013)cm-2,与相同温度下采用常规渗金属工艺相比,提高了1~2个数量级。     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.