基于PC-PLC通信的摩擦焊机网络控制系统

为适应目前工业控制系统网络化的发展,降低控制系统成本,建立了一种摩擦焊机网络控制系统,并进行串口通信实时性和稳定性的研究。主控制站采用工业控制计算机(IPC),从控制站采用三菱FX系列可编程控制器(PLC),计算机闭环控制过程中的开关量信号通过串口通信在两站间实时传送。测试结果表明:网络性能与串口通信程序的优化程度、PLC性能和通信速率密切相关。若采用FX3U PLC,通信速率115.2 kbps,通信过程约在5.8 ms完成。现场应用表明,采用此网络控制系统,摩擦焊机系统的运行速度高、投资小、系统运行稳定可靠。     

去中心化分布式控制系统设计研究

针对上万个被控对象,传统的分布式控制系统无法实现控制器与服务器去中心化,导致效率低且故障率高,设计了一种去中心化分布式控制系统。该系统中的控制器、被控对象、传感器及执行器、服务器通过控制网络进行通信传输,利用冗余备份机制进行控制器动态切换,从而实现控制器去中心化,利用映射表动态更新机制使服务器对相应的被控对象进行数据运算,从而实现服务器去中心化;利用工具箱Truetime2.0及MATLAB/Simulink搭建去中心化分布式电机控制系统仿真平台,以电机为被控对象,研究冗余备份机制对去中心化分布式控制系统的性能影响以及去中心化分布式控制系统的网状网架构能否支持大规模电机正常运行。仿真结果表明,冗余备份机制有效地提高了系统运行的平稳性,系统的网状网架构足以支持上万个电机运行。     

C32摩擦焊机的神经网络PID自适应控制研究

针对C32连续摩擦焊机闭环控制系统的时变性、非线性控制精度较低以及稳定性较差等问题,研究一种BP神经网络与增量式PID控制器相结合的控制算法来提高系统性能.参考C32连续摩擦焊机实际运行参数,通过AMESim软件建立物理模型;结合Simulink建立神经网络PID自适应控制器进行联合仿真,建立电液力闭环控制系统.结果表...     

基于参数优化的电液位置控制系统的最优控制

为提高电液位置控制系统的控制精度，改善系统的动态性能，建立了参数的最优控制指标，优化后得到最优参数，利用最优参数建立电液位置控制系统最优传递函数，对原系统进行优化，应用数值仿真方法，并对优化前后系统的动态性能进行了对比分析。仿真结果表明，优化后系统的超调量和响应时间大幅减小，系统的动态性能得到改善。     

基于PLCN:N网络的模内贴标吹塑机控制系统设计

以吹塑机与贴标机的控制关系作为研究对象,在分析设备控制工艺的基础上,设计了以3个三菱PLC为控制核心的N:N通信网络,给出了系统硬件连接方案,介绍了N:N通信板FX2N-485-BD功能、设置和系统通信实现过程。使用结果表明:通过触摸屏可实现对整个系统的操作和各项工艺参数的设置和监控;该控制系统的结构设计合理,连接方案简单实用,可靠性高,响应快速,定位精确,抗干扰能力强,有良好的性能价格比。     

混合动力挖掘机回转速度控制系统的研究

针对挖掘机回转速度控制系统存在转动惯量变化大、外干扰等不确定性。采用了液压混合动力技术的挖掘机回转装置的速度控制系统进行了鲁棒控制器设计,并进行了校正后系统的仿真验证。采用基于线性矩阵不等式(LMI)的H∞控制器设计方法,通过选择适当的加权函数矩阵,将实际控制系统转化为广义受控对象,设计出满足性能要求的鲁棒控制器。仿真结果表明:所设计的速度控制系统具有较强鲁棒性,能有效地抵抗回转运行过程中的参数摄动和干扰,满足控制系统性能指标。     

基于ZMQ通信架构的巡检机器人离网控制系统

目前工业场景巡检机器人的控制系统大都基于ROS框架。虽然该框架具有很大的开发便利性，但其在运行过程中还是有很大的局限性：通信中断无法重连、低可用性、平台环境强依赖、网络要求高等。提出一种基于ZMQ通信机制的分布式机器人控制系统，通信组件使用ZMQ网络库，并运用分布式思想构建多个机器人业务系统的节点，达到高可用的机器人控制系统。实验结果表明：相比于ROS系统方式，基于ZMQ通信的分布式架构的脱机控制系统具有稳定可靠、网络可重连机制、基本无第三方库依赖等优点，解决了开发、部署使用过程中的问题，可以有效提高巡检机器人的可靠性与稳定性。     

低压熔断器生产线集散控制系统研究

为实现低压熔断器的自动化生产及检测,文章介绍了一种低压熔断器生产线控制系统,并详细阐述了系统的硬件结构、网络接口和控制系统设计。该控制系统采用PLC和上位工控机组成分布式控制系统,采用集散控制方式实现了整条生产线系统的自动化控制。通过多主站PPI通信、PROFIBUS DP和工业以太网构建三层通信网络,该控制系统实现对各个设备的实时监控和数据存储,大大提高了熔断器的生产和检测效率。该系统运行结果证明,低压熔断器控制系统运行稳定、可靠性高。     

CO2焊接超声传感焊缝跟踪控制规则与参数

介绍了一种CO2焊接非接触超声传感焊缝跟踪系统.该系统采用了Fuzzy-P控制理论.由于控制系统的控制规则、控制参数与控制系统性能密切相关,因此,要提高系统的控制性能,必须对系统的控制规则、控制参数进行优化处理.文中首先介绍了Fuzzy-P控制理论和参数自调整模糊控制规则;然后通过计算机仿真研究,确定了参数自调整模糊控制的比例因子α1和α2、系统输出比例因子K等控制参数,确定了Fuzzy-P控制的阈值ev.试验结果表明,采用计算机仿真研究确定的Fuzzy-P控制规则和控制参数是正确的,能够满足实际CO2焊接超声传感焊缝跟踪系统的控制要求.     

切换网络控制系统鲁棒H∞容错控制

研究一类具有参数不确定的网络化控制系统,同时考虑数据丢包和网络时延对系统性能产生的影响,将服从伯努利丢包的网络控制系统视为以一定速率切换的开关.针对既有传感器失效又有执行器失效的故障情形,引入一种状态反馈控制器,并基于Lyapunov理论和异步动态系统理论,对网络控制系统进行鲁棒容错控制问题的研究,给出系统在此情形下保...     

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.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

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.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.