An Adaptive Model and Algorithm for an Electrohydraulic Position Servo System in Auto Gauge Control for Aluminum Hot Tandem Mill

The electrohydraulic servo position control system (HPC) is the core of an auto gap control for a modern fourhigh continuous hot strip mill. The actuators are loaded with considerable external disturbances, rolling forces, and the system stiffness and position accuracy will become hypersensitive to the leakage and the compressibility of the oil. Many efforts have being made to increase the position accuracies. The conventional resources are proportion integral differential (PID) controller. But the PID controller is faint for a considerable external disturbance. In this paper, by introducing the adaptive control strategy of model reference the reciprocities of the system structure with the loads were analyzed. With the Lyapunov energy function, an adaptive control algorithm applied to improve the system accuracy was formulated. The system simulations and the selection of parameters of the model were also discussed. The simulations show the static state errors at 0.02%. Finally, the industrial experimental result was given.     

In Situ Growth Process of Mg-Al Hydrotalcite Conversion Film on AZ31 Mg Alloy

In this study,an environment-friendly hydrotalcite film has been deposited on AZ31 Mg alloy by a twostep technique.To improve conversion film technique and control film properties,batch studies have been carried out to address various process parameters such as immersion time,pH value,and temperature of the treatment solution.The morphologies and chemical composition were characterized by scanning electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS).The corrosion resistance of the samples with the various final films was then further compared by polarization curves.It can be concluded from the results that,at low value of pH,temperature,or long deposition time,the precursor film is mainly composed of a cracked layer.The transformation of hydrotalcite film is largely influenced by the pH value.There are optimum values of pH,temperature of the coating bath and immersion time for the film formation process to achieve the best quality and corrosion resistance of the hydrotalcite film.The optimum process is as follows:the sample is first immersed in the pretreatment solution with a pH value of about 8 at a temperature of 60 ℃ for 30 min to form a precursor film and then this precursor film is immersed into the post treatment solution with a pH of 10.5 at 80 ℃ for 1.5 h to obtain the Mg—Al hydrotalcite conversion film.     

Design of Variable Structure Control by Using the L_2 Gain Method

The robust stabilization problem for a family of nonlinear plants with mismatch uncertainties is addressed,and a solution is presented based on variable structure control theory and H∞ control theory.A kind of boundary layer is built near the ideal switch surface which can eliminate chattering in the switch surface.The proposed control method with L2 gain can guarantee exponential stability of a system state with no parameter uncertainty and external disturbance,while it can guarantee state ultimate boundness if parameter uncertainty and external disturbance exist.In the proposed design method,stability of the closed-loop system is analyzed by adopting the Lyapunov function approach.Finally the numerical simulation results show that the proposed smooth variable structure controller has good performance without chattering in the switch surface.     

Effects of Process Parameters on the Temperature Field in Ti-6Al-4V Alloy Blade Precision Forging Process

Blade precision forging is a high temperature and large plastic deformation process. Process parameters have a great effect on temperature distribution in billet, so in this paper, by taking a Ti-6Al-4V alloy blade with a tenon as an object, the influence of process parameters on the temperature distribution in precision forging process was investigated using 3D coupled thermo-mechanical FEM （finite element method） code developed by the authors. The results obtained illustrate that： （1） the gradient of temperature distribution increases with increasing the deformation degree; （2） with increasing the initial temperature of the billet, the zones of high temperature become larger, and the gradient of temperature distribution hardly has any increase; （3） friction factors have little effect on the distribution of temperature field; （4） with increasing upper die velocity, temperature of the billet increases while the temperature gradient in billet decreases. The results are helpful to the design and optimization of the process parameters in precision forging process of Ti-alloy blade.     

Multi-scale modeling of liquid-metal cooling directional solidification and solidification behavior of nickel-based superalloy casting

Liquid-metal cooling(LMC)process can offer refinement of microstructure and reduce defects due to the increased cooling rate from enhanced heat extraction,and thus an understanding of solidification behavior in nickel-based superalloy casting during LMC process is essential for improving mechanical performance of single crystal(SC)castings.In this effort,an integrated heat transfer model coupling meso grain structure and micro dendrite is developed to predict the temperature distribution and microstructure evolution in LMC process.An interpolation algorithm is used to deal with the macro-micro grids coupling issues.The algorithm of cells capture is also modified,and a deterministic cellular automaton(DCA)model is proposed to describe neighborhood cell tracking.In addition,solute distribution is also considered to describe the dendrite growth.Temperature measuring,EBSD,OM and SEM experiments are implemented to verify the proposed model,and the experiment results agree well with the simulation results.Several simulations are performed with a range of withdrawal rates,and the results indicate that 12 mm·min^-1is suitable for LMC process in this work,which can result in a fairly narrow and flat mushy zone and correspondingly exhibited fairly straight grains.The mushy zone length is about 4.8 mm in the steady state and the average deviation angle of grains is about 13.9°at the height 90 mm from the casting base under 12 mm·min^-1withdrawal process.The competitive phenomenon of dendrites at different withdrawal rates is also observed,which has a great relevant to the temperature fluctuation.     

Design of Remote Monitoring System for Ceramic Electric Kiln

In order to improve the management and control requirements of small electric kilns in ceramic production field. According to the excessive dispersion of electric kilns in porcelain production field, a remote monitoring system based on RS485 bus and Modbus protocol is designed. The system consists of data acquisition, field control, cloud monitoring and communication protocol. MCGS is used as the master station to communicate with the temperature controller, collect and transmit the internal dat...     

Data acquisition, analysis and applications of multi-sensor integration

This paper presents some key techniques for multisensor integration system, which is applied to the intelligent transportation system industry and surveying and mapping industry, e.g. road surface condition detection, digital map making. The techniques are synchronization control of multisensor, spacetime benchmark for sensor data, and multisensor data fusion and mining. Firstly, synchronization control of multisensor is achieved through a synchronization control system which is composed of a time synchronization controller and some synchronization subcontrollers. The time synchronization controller can receive GPS time information from GPS satellites, relative distance information from distance measuring instrument and send spacetime information to the synchronization subcontroller. The latter can work at three types of synchronization mode, i.e. active synchronization, passive synchronization and time service synchronization. Secondly, spacetime benchmark can be established based on GPS time and global reference coordinate system, and can be obtained through position and azimuth determining system and synchronization control system. Thirdly, there are many types of data fusion and mining, e.g. GPS/Gyro/DMI data fusion, data fusion between stereophotogrammetry and PADS, data fusion between laser scanner and PADS, and data fusion between CCD camera and laser scanner. Finally, all these solutions presented in paper have been applied to two areas, i.e. landborne intelligent road detection and measurement system and 3D measurement system based on unmanned helicopter. The former has equipped some highway engineering Co., Ltd. and has been successfully put into use. The latter is an ongoing research.     

Heterostructured crystallization mechanism and its effect on enlarging the processing window of Fe-based nanocrystalline alloys

The harsh melt-spinning and annealing processes of high saturation magnetization nanocrystalline softmagnetic alloys are the biggest obstacles for their industrialization. Here, we proposed a novel strategy to enlarge the processing window by annealing the partially crystallized precursor ribbons via a heterostructured crystallization process. The heterostructured evolution of Fe_84.75Si₂B₉P_3C0.5Cu_0.75(at.%)alloy ribbons with different spinning rate were studied in detail, to demonstrate the gradient nucleation and grain refinement mechanisms. The nanocrystalline alloys made with industrially acceptable spinning rate of 25-30 m/s and normal annealing process exhibit excellent magnetic properties and fine nanostructure. The small quenched-in crystals/clusters in the free surface of the low spinning rate ribbons will not grow to coarse grains, because of the competitive grain growth and shielding effect of metalloid elements rich interlayer with a high stability. Avoiding the precipitation of quenched-in coarse grains in precursor ribbons is thus a new criterion for the composition and process design, which is more convenient than the former one with respect to the homogenous crystallization mechanism, and enable us to produce high performance nanocrystalline soft-magnetic alloys. This strategy is also suitable for improving the compositional adjustability, impurity tolerance, and enlarging the window of melt temperature,which is an important reference for the future development of composition and process.     

Synthesis of Nano-sized Barium Titanate Powder by Solid-state Reaction between Barium Carbonate and Titania

Size control of BaTiO3 in solid-state reaction between BaCO3 and TiO2 was demonstrated by varying the size of TiO2 and milling conditions of BaCO3. The smaller TiO2 particles had higher surface area, resulting in faster initial reaction. The mechanically milled BaCO3 particles accelerated the diffusion process and decreased the calcinations temperature. It can be deduced from the results that the size control is possible and nano-sized BaTiO3 particles with about 60 nm can be synthesized by using the conventional solid-state reaction between BaCO3 and TiO2.     

Effects of Solution Temperature on Tensile Properties ofSiC_w/2024Al Composite

The effects of solution (quench) temperature on the properties of SiCw/Al composite have been investigated using tensile tests. The experiments indicate that the solution temperature of the composite fabricated by P/M technique can be raised to 560℃. The tensile strength of the composite is obviously dependent on solution (quench) temperature and the composite solutionized at 540℃ exhibits a maximum of tensile strength and elongation-to-failure. These results can be accounted for by the variation of the dislocation density in the composite.     

ADuC812单片机温度控制器

本文提出的单片机温度控制器，是以ADuC812芯片为核心，根据PID控制原理构成的数字控制器，文中论述了它的硬件设计方法，并给出了几组主要测试曲线，研究结果表明，该温度控制器的硬件设计简单，成本低，功耗小，体积小，控温效果好，具有实用价值。     

基于模糊控制的HVPE生长设备温度控制系统

氢化物气相外延（hydride vapor phase epitaxy,HVPE）工艺的关键是确保加热炉的温场恒定和高精度控制。由于HVPE生长设备温度控制过程涉及多个加热温区,以及温度测量元件和电阻加热炉温度传导引起的延迟,其温度控制存在超调过大、控制精度低和调节时间过长等问题。为实现HVPE生长设备反应室内温度的精准调控,将模糊逻辑应用到PID （proportion integration differentiation,比例积分微分）控制中,设计系统各温区的模糊自适应整定PID控制器。依据实际设备与相应技术要求,设计研发了一套基于PLC （programmable logic controller,可编程逻辑控制器）、温度控制电路以及模糊自适应整定PID控制的HVPE生长设备温度控制系统。Simulink仿真结果与实测结果表明,模糊自适应整定PID控制器可以应用于HVPE生长设备的温度控制系统,且控制效果较好。研究表明,所设计的温度控制算法与温度控制系统能够很好地满足GaN材料生长的工艺要求,具有一定的实用价值。     

热合装置 PLC 温度控制系统研究与开发

目的更精确地控制热合机热合装置的温度,提高热合装置压合袋口时的封口质量。方法提出了一种基于模糊自整定PID的温度控制器方案。把常规的PID控制方式同模糊控制结合起来,对PID参数进行在线修正。将常规PID和模糊PID温度控制算法在西门子PLC中编程实现,并将该方式与常规PID控制方式进行了对比。结果模糊控制方式较传统的PID控制能更稳定控制加热温度,有效提高了响应速度和控制精度。结论模糊PID温度控制系统具有更好的温度控制效果,能够提高热合装置的封口质量。     

基于模糊内模-PID的包装机热封切刀温度控制

目的 包装机热封切刀温度控制系统存在非线性、大滞后性等特点,传统PID控制的效果也越来越无法满足工艺生产的要求,为了提高包装机热封切刀温度控制的速度和精度,进而提高封口的质量,以提高产品包装效率和品质。方法 在传统的PID控制的基础上,通过结合模糊控制和内模控制理论的先进控制算法,提出模糊内模-PID控制算法的包装机热封切刀温度控制系统。内模控制能够使PID控制器参数进行简化,同时模糊控制的引入能够实现控制器参数的在线调整,将该新型控制算法应用到包装机热封切刀温度控制系统中,并与传统控制进行对比。结果 通过Matlab仿真软件搭建模内模-PID控制的包装机热封切刀温度控制系统仿真平台,仿真结果表明,系统响应速度、精度、超调量、抗扰动能力等比传统控制系统性能更加优良。结论 通过仿真验证了模糊内模-PID控制在热封切刀温度控制系统上的有效性和可行性,能够在温度控制系统中表现出优良的性能指标。     

HTF58X2注塑机螺杆筒温度的模糊PID控制

分析了HTF58X2注塑机螺杆筒温控系统的特点与要求。考虑到传统PID控制器中的螺杆筒温控系统因具有非线性、纯滞后、时变性而难以取得满意的温控效果,提出了一种基于模糊策略的PID参数在线整定的自适应控制器。该控制器根据现场输入的温度偏差和偏差变化率,通过模糊推理对PID控制器参数进行在线调整,以适应不同工况下PID参数的最佳匹配。Matlab/Simulink仿真和实验测试的结果表明,模糊-PID控制器与固定参数的PID控制器相比,在调节速度、超调量和自适应能力等方面具有一定的优势。     

防护热板法导热仪的温度控制

导热仪的温度测量和控制水平不高是导致测量结果产生偏差的重要原因。防护热板导热仪具有较大的热惯性,需要被控制温度的单元多,彼此有热传递作用,形成非线性的相互干扰,如果控制参数的整定不合适,系统各个单元的温度就会随时间波动。在国产精密工业温度计、测温仪、直流电源,LabVIEW虚拟PID控制器构成的导热仪温控系统上,分段优化整定导热仪系统PID控制参数,并研究了导热仪各部件温度控制顺序对整体控温效果的影响。实验结果表明在常温至400℃的范围,导热仪各个单元的温度被长时间稳定控制在±0.01℃以内,此参数整定方法可满足高精度防护热板导热仪的技术要求。     

空调房间温度模糊分数阶PID控制器的设计

针对具有大时滞、大惯性和时变等动态特性的空调房间对象,综合模糊控制与分数阶PID控制理论,提出了模糊分数阶PID室温控制器的设计方法.首先,对于空调房间温度对象,进行数学建模.然后,运用模糊控制规则,获取相应的分数阶PID室温控制器的控制参数,从而构建出空调房间温度的模糊分数阶PID控制系统.并且,通过数值仿真对其进行验证.结果表明,该模糊分数阶PID室温控制器是可行的,与分数阶PID控制器相比,具有更好的控制性能.     

基于RBF神经网络的自动包装机温度控制算法研究

目的针对传统热封工艺中温度调节PID算法参数过度依赖人工经验的缺点,提出一种RBF神经网络与PID算法相结合的具有参数自适应的热封温度控制算法。方法使用控制系统的输出误差作为代价函数,采用最小均方误差(LMS)调整权值与偏置参数,并通过中心自组织算法实现径向基函数中心和中心宽度的动态调节,在Matlab软件中的Simulink子系统中建立仿真模型进行算法验证,并与传统PID控制算法进行比较。结果仿真结果表明,径向基神经网络与传统PID算法的结合使得系统输出响应在动态性能和静态性能方面均优于传统PID,在系统上升时间、调节时间等方面均优于增量式数字PID。结论将RBF神经网络PID算法应用于自动包装机,避免了传统热封工艺中PID控制算法参数不能适应于复杂变换控制环境的问题,神经网络PID算法的自适应性强,实现了热封温度变化下PID参数的自动调整,在一定程度上提升了生产效率和包装设备的智能化水平。     

恒温供水风冷冷水机组的研制

本文主要对恒温供水风冷冷水机组的设计原理进行说明,该机组具有恒温供水、节能、结构紧凑等特点,其控制方式为工业控制器与PID调节表相结合。经实际运行结果表明,恒温供水风冷冷水机组具有节能、使用方便、运行状态可靠稳定等优点。     

空调客车内温度控制系统仿真研究

分别采用模糊控制方法与常规PID控制方法，对空调客车内温度控制系统进行了仿真研究。仿真结果表明，PID控制能消除稳态误差，但超调大，过渡时间长，在工况变化较小的情况下，能满足一定的控温要求；对于对象延迟、工况变化较大的场合，模糊控制能实时跟踪空调工况变化，较快地达到控温目标值，节能率高，综合控制效果比PID要好。