基于变论域自适应模糊PID的压铸机压射速度控制研究

压铸机控制系统是一个非线性、大滞后的复杂系统,传统的压射速度控制算法难以保障精密铸件的压铸品质。对压铸机速度控制系统进行数学建模分析,将变论域与自适应模糊PID技术结合起来,设计了变论域自适应模糊PID控制算法,结果表明,该算法能精确有效地控制电液伺服阀,压射速度动态响应平稳无超调,响应快以及鲁棒性好。     

自适应模糊PID在压铸机控制系统中的应用

为改善压铸机在生产现场的抗干扰性,提高系统的稳定性,采用自适应模糊PID控制技术,进行了模糊算法设计及压射系统数学模型的分析。利用模糊控制器的智能非线性特征弥补PID控制器不足,更好地控制电液比例阀,使系统达到更优的控制状态。通过实验仿真可知,该算法可以减少系统的稳态误差,提高系统抗干扰性。     

基于逆系统方法的压铸机快压射速度控制

压铸机在工作过程中由于液压元件的节流特性及液压动力元件的死区、滞环和限幅等因素使系统具有较强的非线性。为了提高压铸机快压射阶段速度系统的鲁棒性,提出一种基于逆模型的控制算法。建立速度系统的非线性模型;分析系统的可逆性,将系统线性化为伪线性系统;利用反馈控制设计线性系统控制器,实现对系统的控制。利用MATLAB验证基于逆系统方法的压铸机快压射速度控制的有效性。     

P—Q~2图及其应用价值(二) 有效压力线

P—Q~2图说明了压铸过程快压射阶段的性能,即压铸机传给金属的压力和流量的相互关系。压铸上内金属所需压力和压铸机传递的压力能在同一图模表示。因此,可以预测金属临界流动状态。 在研究有效压力线(通常称为机床线)的过程中,深入了解了压铸机压射系统,发现一些锌合金压铸机性能不佳。然而,改造这种压射系统并不困难,压铸厂自己就可进行。通过改造可使压铸机能力提高2—3倍,为改进老设备,增加生产能力,找到了有效方法。     

基于改进差分进化算法的机械手轨迹控制

为提高机械手系统的轨迹控制精度,提出了一种基于改进差分进化算法(Differential Evolution, DE)的机械手轨迹控制方法。以单关节机械手为研究对象,首先,假设其做摆线运动,同时采用PD控制方法跟踪机械手实际运动轨迹;然后,提出改进差分进化算法,优化整个运动过程中机械系统消耗的能量,进而得到一组最优的离散偏差;最后,对这些离散偏差使用三次样条插值法,从而得到连续的机械手实际的运动轨迹。与差分进化算法进行仿真对比,该控制方法得到的机械手运动轨迹精度更高、消耗的能量更少。     

冷室压铸机压射速度的匀加速控制

目前冷室压铸机的压射过程大多采用三级压射的控制方法,不仅给压铸机的调整带来不便,而且还对压铸件的质量和压铸机本身产生不良影响。为了克服这些缺陷,提出了压射速度的匀加速控制,并给出了一种压射速度匀加速控制系统的控制方法、基本组成和控制过程。在实际应用中,通过对原压铸机的液压系统和电气系统进行改造,实现了压射速度的匀加速控制,并取得了良好的效果,从而为压铸机压射速度的控制提供了一种简便而有效的方法。     

变异模糊神经网络算法在压铸机PID闭环压射系统中的应用

针对压铸机压射系统在不同阶段对压力PID闭环控制效果的要求,提出一种变异的模糊神经网络算法对控制系统快速压射阶段进行PID参数优化,对快速压射阶段的压力系统进行模糊寻优。引入的遗传因子自动进行变异,对速度与压力模型快进行参数迭代优化。搭建了仿真平台,通过仿真实验证明,提出的算法可以大大提高压铸机速度与压力的控制效果,其超调量、调整时间明显得到改善,同时也提高了压铸机控制系统的整体压射效率。     

基于模糊PID控制的压铸机实时控制系统设计

为了克服当前压铸机控制系统中存在的不足,设计了一种以ARM为控制核心的压铸机实时控制系统,采用自适应模糊PID控制策略对压射蓄能器与增压器的电液比例阀纠偏控制,完成对压射速度与增压压力等参数的闭环控制与实时监控,通过硬件与软件的相应设计,实现了压铸机工况的实时控制。研究结果为提高压铸机自动控制水平提供借鉴。     

基于差异进化算法的数控永磁直线同步电动机优化设计

在标准差异进化算法(DE)的基础上,提出一种改进的差分进化算法,该算法从动态更新种群、关键参数自适应处理两个方面进行了改进。针对永磁直线同步电动机的特点,运用有限元法精确的求解直线电机内的磁场分布,分别计算边端力和齿槽力后合成得到磁阻力,并将有限元数值分析与DE法相结合,为提高数控系统中直线电动机运行的平稳性,对其磁阻力进行最小优化,具体实例的优化计算结果表明DE算法与有限元结合是电机优化设计领域中一种行之有效的方法。     

压铸机压射系统的试验研究

本文介绍J1125C型压铸机压射机构、增压系统和液压系统的设计原则,研究了压射工艺参数之间的关系。文中重点介绍增压系统中增压控制阀的结构及其控制方法;影响压射速度的因素。最后根据试验中出现的问题,提出了改进压铸机设计的建议。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.