采煤机滚筒调高智能化控制系统优化设计

为提高采煤机滚筒调高智能化控制精度,对基本萤火虫算法进行改进。对采煤机滚筒调高智能化控制系统进行数学建模,利用改进的萤火虫算法进行滚筒控制系统PID参数寻优,并搭建滚筒调高智能化控制系统Simulink仿真模型;对采用改进和基本萤火虫算法系统的响应进行分析。结果表明：系统在阶跃信号、斜坡信号及不同类型干扰信号情况下,改进萤火虫算法优化的PID控制器的系统响应性能和抗干扰性能均得到明显改善;阶跃信号下,优化后系统的超调量减小21.6%;斜坡信号下,优化后系统超调量减小38.4%;脉冲干扰信号下,优化后系统超调量减小21.9%;阶跃干扰信号下,优化后系统超调量减小33.2%;随机干扰信号下,优化后的响应曲线波荡范围减小40.1%。     

基于BP-PID的选择性激光烧结温度控制系统设计

为消除纯滞后系统的超调、改善温度因素对制件质量和强度的影响,设计一种基于BP-PID算法的选择性激光烧结温度控制系统.该系统采用层次化架构和模块化的设计方案,以STM32控制器作为主控模块,并利用BP神经网络改进传统比例-积分-微分(PID)算法,提高了控制系统的稳定性且效果显著.通过MATLAB进行仿真模拟,与传统PID控制进行对比并进行实验.结果表明:BP-PID算法能迅速整定最优参数,且超调量小,达到稳态所用时间更短;在设定预热温度为90℃且采用BP-PID算法控制时,系统稳态误差在±1℃之内,超调量小于3％.     

基于模糊PID的伺服压力机位置控制系统

伺服压力机是目前成形装备发展的一个新方向.为了提高其位置控制的响应特性,针对其非线性、时变性、滞后性,提出了基于模糊算法和PID算法的模糊PID控制器,在C++ Builder中开发模糊PID控制器以实现PID参数的在线修正.阶跃响应和正弦跟随的实验结果表明,所设计的模糊PID控制器能够有效的提高响应速度、降低超调量和稳态误差,并且具有较强的抗干扰能力.模糊PID控制器拥有比传统PID控制器更好的控制效果,可以有效的提高伺服压力机位置控制性能.     

二次调节转速系统的自适应神经模糊PID控制

阐述二次调节转速系统的原理并建立其数学模型.针对系统参数时变、非线性的特点,设计一种自适应神经模糊PID控制器,该控制器利用PID算法实现准确控制,通过神经模糊控制提高控制的自适应性.利用MATLAB模糊逻辑工具箱对系统进行仿真,并与传统PID控制进行比较.结果表明:采用自适应神经模糊PID控制,系统响应快、超调小、过渡时间短、能够较好地抑制干扰,具有良好的动态特性和稳定性.     

一种新型模糊神经网络滑模控制器设计北大核心

针对基于PID算法的永磁同步电机矢量控制系统易受系统不确定性影响(负载扰动、模型参数变化)的问题,提出一种新型模糊神经网络滑模控制器。首先,在传统滑模控制的基础上,利用模糊神经网络控制器(FNN)构成滑模控制器(SMC)的切换控制项来完成对系统不确定性因素进行逼近以及对滑模控制切换增益的调节;其次,利用麻雀搜索算法来实时更新模糊神经网络滑模控制器参数,为了加快SSA的收敛速度以及防止其陷入局部最优,利用分数阶微积分对传统麻雀算法进行改进;最后,进行了仿真验证,表明所设计的新型模糊神经网络滑模控制器具有较强的鲁棒性和动态性能。     

基于PSO算法的串联机械手位置跟踪模糊PID控制（英文）

在串联机械手运动控制中常采用PID控制器,存在超调较大、跟踪精度低的问题,为此设计了一种基于微粒群(PSO)算法的模糊PID控制器。首先,根据两力臂串联机械手模型,推算出动力学方程式和传递函数;然后,设计控制器的系统结构,采用PSO算法优化模糊PID控制参数,提高了系统的自适应能力和跟踪精度;最后,在MATLAB中对机械手位置跟踪控制进行仿真。仿真结果显示:PID控制超调较大,有震荡;经模糊调整后,超调变小,稳定性较好;再通过PSO优化,响应速度变快,超调量基本消除。     

基于分数阶PID的宏微复合驱动器宏动控制策略

针对宏微复合驱动器控制系统中存在定位误差大和调节时间长的问题,提出了一种基于次最优分数阶PID的控制策略。简述了宏微复合驱动器结构及工作原理,并基于电磁驱动原理建立了宏动部分数学模型;设计了分数阶PID控制器,并采用遗传算法和次最优的方法对控制器进行参数整定;通过数值仿真和实验验证了分数阶PID控制器的有效性。结果显示,采用分数阶PID控制器相较于传统PID控制器在5 mm以及更大定位行程中位移超调量下降超过57%,调节时间减少超过24%,且行程越大驱动器采用分数阶PID控制器控制效果越明显。研究结果表明,分数阶PID控制器在宏微复合驱动器宏动系统中的控制效果明显优于传统PID控制器。     

基于BP神经网络PID的高速清扫车摆臂控制系统

针对传统清扫车摆臂开环控制系统的动态响应特性不足、抗干扰能力弱,不能适应高速工况下清扫作业,设计了高速清扫车摆臂执行机构和闭环控制系统。为解决BP神经网络(BPNN)存在局部极值、收敛速度慢等问题,提出一种改进BPNN PID算法,其核心是通过主动串联校正,抑制PID前一次输出值u (k-1)对此次输出值u (k)的影响。通过搭建Simulink-AMESim联合仿真模型,研究了高速清扫车摆臂闭环控制系统的阶跃响应、抗干扰能力以及位置跟踪能力。研究结果表明:所改进的BPNN PID控制器能够动态调整PID参数,提高了系统的适应性、准确性和稳定性;改进BPNN PID控制器的抗干扰能力更强,鲁棒性更好,且系统近乎没有超调,超调量为0.5%,仅为PID控制超调量的2.34%,稳定时间0.62 s,相比PID提前了66.31%。     

铝板铸轧前槽液面模糊PID控制技术研究

针对前槽液位控制具有非线性、多扰动、迟延性等特点,传统的PID控制由于适应性不足,往往不能满足设计精度要求,故提出了将参数自调节模糊PID控制器应用于前槽液位控制系统中。该方法利用模糊推理在线调整PID参数,使液位控制系统在不同状态下能获得更好的控制效果。Simulink仿真结果表明,模糊PID控制器能够使系统的动态和静态特性明显改善,超调量小,响应速度快,调整时间短。     

基于改进PSO算法的EHA叉车举升系统仿真分析

为改善EHA叉车举升系统的动态特性,建立系统的电机和液压部分数学模型。针对传统PID控制系统参数调整困难、超调量大、响应速度慢等问题,将改进PSO优化算法与PID控制器相结合,提出一种PSO-PID控制器。通过MATLAB/Simulink搭建整个系统的仿真模型,对比分析采用传统PID控制与PSO-PID控制的系统的动态性能,结果表明:基于PSO-PID控制的系统,其超调量明显降低,系统的响应速度、控制精度和位移跟踪性能都得到显著提高。     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.