Contro1Logix控制器在备煤系统中的应用

针对备煤系统的工艺流程,为生产合格焦煤,保证焦炉高效生产,对备煤系统进行自动化构建。运用计算机、可编程控制器、工业电视实现备煤集中控制、远程通信、数据共享等功能。该系统功能强大,提高了生产效率,减少操作定员,适应现代化工业控制发展需求。

Fuzzy Control Method for Gasoline Engine Idle Speed Control

In order to improve the steady and dynamic characteristic of the idle speed control and study the performance of the fuzzy control method for the idle speed control, a fuzzy control system is developed to control the idle speed of gasoline engine. The construction and working principle of the fuzzy controller are described, and the design procedure of the fuzzy controller is given in detail. The control parameters are determined by computer simulation. The simulation and experiments on the engine test bench show that the idle speed is controlled accurately both in stationary and in dynamic states, and the fuzzy control method is robust to the changes of engine parameters.

ControlNet协议的通信机理分析

在详细探讨 Control Net现场总线各数据链路层协议的基础上 ,部分结合随机 Petri网方法对协议的节点内部处理以及隐含令牌传递机制进行分析 ,着重就协议的生产 /消费者模型给出了与实时性相关的性能指标计算方法 。

Recent progress and application on seismic isolation energy dissipation and control for structures in China

China is a country where 100% of the territory is located in a seismic zone. Most of the strong earthquakes are over prediction. Most fatalities are caused by structural collapse. Earthquakes not only cause severe damage to structures, but can also damage non-structural elements on and inside of facilities. This can halt city life, and disrupt hospitals, airports, bridges, power plants, and other infrastructure. Designers need to use new techniques to protect structures and facilities inside. Isolation, energy dissipation and, control systems are more and more widely used in recent years in China. Currently, there are nearly 6,500 structures with isolation and about 3,000 structures with passive energy dissipation or hybrid control in China. The mitigation techniques are applied to structures like residential buildings, large or complex structures, bridges, underwater tunnels, historical or cultural relic sites, and industrial facilities, and are used for retrofitting of existed structures. This paper introduces design rules and some new and innovative devices for seismic isolation, energy dissipation and hybrid control for civil and industrial structures. This paper also discusses the development trends for seismic resistance, seismic isolation, passive and active control techniques for the future in China and in the world.

A meta-analysis of randomized controlled trials of acupuncture bloodletting for shingles

Objective:To systematically evaluate the clinical efficacy of acupuncture bloodletting therapy for herpes zoster.Methods:The computer searched the CNKI,WanFang,VIP,CBM,PubMed,and Cochrane Library databases.The time limit was from the establishment of the database to December 31,2019.Relevant literatures on randomized controlled trials of spinal bloodletting for shingles were retrieved.Data were extracted and quality evaluated based on the Cochrane bias risk assessment method.Meta analysis was performed using Rev Man5.3 and Stata15 statistical software.Results:(1)A total of 21 Chinese literatures were included,with a total of 1,533 patients;(2)Meta-analysis was performed using a fixed effect model,and the results showed that the total effective rate of the experimental group(OR=5.11,95%CI:(3.48,7.50),Z=8.33,P<0.00001)is better than the control group,the difference is statistically significant;(3)VAS score analysis using a random effects model(MD-2.23,95%CI(-2.46,-1.99),p<0.0001)(4)The incidence of sequela neuralgia was analyzed using a random effects model(OR=0.21,95%CI:(0.09,0.51),Z=3.48,P=0.0005).Conclusion:The effect of spinal bloodletting on the treatment of shingles and VAS scores,symptomatic relief,and the incidence of sequela neuralgia have advantages.

利用WebBrowser Control实现程序界面与实现的分离

开发Windows应用程序时常会有界面自定义的需求,这就意味着程序界面与实现代码必须松耦合,传统方式下需要运用设计模式来实现,而设计模式的使用较为复杂。本文介绍的使用浏览器控件的方法,无需开发人员了解设计模式即可方便地满足上述需求,降低了开发难度,且使得程序有较好的可扩展性,在程序设计中有很大的实用价值。

On the Aristocratic Control of Regime in the 18th-century England

在欧洲各国贵族于本国资产阶级革命后纷纷衰落的时候,英国贵族阶层不但掌握着政权,而且加强了对政权的控制。这是英国的其他任何阶层和其他国家的贵族阶层所望尘莫及的,这一现象必然有其原因。本论文将就这一现象从英国贵族起源和当时社会历史背景作简要分析。

Development of nonlinear disturbance observer based control and nonlinear PID： A personal note

This paper gives an overview of early development of nonlinear disturbance observer design technique and the disturbance observer based control （DOBC） design. Some critical points raised in the development of the methods have been reviewed and discussed which are still relevant for many researchers or practitioners who are interested in this method. The review is followed by the development of a new type of nonlinear PID controller for a robotic manipulator and its experimental tests. It is shown that, under a number of assumptions, the DOBC consisting of a predictive control method and a nonlinear disturbance observer could reduce to a nonlinear PID with special features. Experimental results show that, compared with the predictive control method, the developed controller significantly improves performance robustness against uncertainty and friction. This paper may trigger further research and interests in the development of DOBC and related methods, and building up more understanding between this group of control methods with comparable ones （particularly control methods with integral action）.

Phase Transformation Behavior and Microstructural Control of High-Cr Martensitic/Ferritic Heat-resistant Steels for Power and Nuclear Plants: A Review

The martensitic/ferritic steels have been used as boiler and turbine materials in power plants, and also been selected as potential materials for structural materials in nuclear reactors. In this paper, the kinetic analysis of the martensite formation and microstructural control of high-Cr martensitic/ferritic steels are reviewed. A modular approach, incorporating Fisher partitioning nucleation and anisotropic growth for impingement, was proposed to describe the martensite formation kinetics under different cooling rates.The kinetic analysis suggested a thermal-activated growth feature occurring during the martensitic transformation of martensitic steels. The microstructure can be tuned by composition optimization and various combinations of heat treatment parameters(temperature, time, severe and minor deformation).For the application in power plant, the potential of boundary-design, refinement of original austenite grain size and the final martensitic lath, pinning effect of stable carbides, in improving the performances of martensitic/ferritic steels at elevated temperatures should be investigated more thoroughly.Furthermore, efforts should be made to explore the effects of retained austenite on the improvement of high-temperature creep strength. For the application of nuclear plants, attempts should also be made to produce Fe powders with uniformly distributed oxide particles by chemical reactions.

Principle and Implementation of an MC4044-Based Phase Locked Loop for Constant Speed Control

An inexpensive MC4044-based phase locked loop for constant speed control of a DC motor is discussed. It operates on a principle similar to that of a frequency synthesizer. The paper introduces the system configuration with a detailed description of its operating principle, some practical design considerations are discussed with an experimental study to test the control performance of the newly designed system. The experimental result shows that the phase locked control system can regulate the speed of a DC torque motor with a precision up to 0.0022%(1).[

Ultrasonic attenuation spectroscopy for multivariate statistical process control in nanomaterial processing

Ultrasonic attenuation spectroscopy （UAS） is an attractive process analytical technology （PAT） for on-line real-time characterisation of slurries for particle size distribution （PSD） estimation. It is however only applicable to relatively low solid concentrations since existing instrument process models still cannot fully take into account the phenomena of particle-particle interaction and multiple scattering, leading to errors in PSD estimation. This paper investigates an alternative use of the raw attenuation spectra for direct multivariate statistical process control （MSPC）. The UAS raw spectra were processed using principal component analysis. The selected principal components were used to derive two MSPC statistics, the Hotelling＇s T2 and square prediction error （SPE）. The method is illustrated and demonstrated by reference to a wet milling process for processinR nanoparticles.

State control, access to capital and firm performance

We study the effect of state control on capital allocation and investment in China, where the government screens prospective stock issuers. We find that state firms are more likely to obtain government approval to conduct seasoned equity offerings than non-state firms. Further, non-state firms exhibit greater sensitivities of subsequent investment and stock performance to regulatory decisions on stock issuances than state firms. Our work suggests that state control of capital access distorts resource allocation and impedes the growth of non-state firms. We also provide robust evidence that financial constraints cause underinvestment.

基于电驱动的智能播补一体化马铃薯播种机设计研究

马铃薯是我国重要的粮食和经济作物,在西南丘陵山区受限于地势条件,现有马铃薯播种机在作业时均不同程度的存在株距误差大、漏播及重播率高、土壤条件适应性差的问题。为此,设计了以AT89S51单片机为运算核心的播补薯一体机,主要由漏播监测、播补薯、株距控制模块组成。其中,漏播监测模块主要由红外线发生和接收装置组成,播补薯模块主要由步进电机驱动的取种勺根据系统命令执行指定作业,株距控制模块则通过设定的株距指令控制电机的转速及修正;同时,以步进电机作为动力取代了传统的地轮驱动以减小株距误差,步进电机驱动的单链取种勺集成播补薯功能于一体。试验表明:机具作业行走速度在0.6~1m/s时,补薯成功率为73%~81%,总播种成功率为97%~98%,播种株距误差为2.52%~4.83%,整体播种性能完全满足马铃薯播种农艺要求。

长江弯曲航道船舶航迹控制方法研究

文中建立考虑舵机伺服系统特性和风、流干扰的线性船舶动力学模型,确定仿真实验船舶的各个必要参数.引入最优控制策略,以航速为自变量设计不同航速下基于最优控制策略的PID(proportion integral differential)航向控制器OP-PID Controller(optimal PID controller),在不同航速下分别采取PID和OP-PID进行了航向控制仿真.在航向控制器的基础上,结合航段跟踪决策算法、改进的LOS(line-of-sight)制导方法获取航向偏差,以航向偏差驱动OP-PID间接航迹控制器.以OP-PID和改进的LOS组成的航迹控制方法进行了静水环境中和外界干扰下的航迹控制仿真实验.结果表明:基于改进LOS制导方法和OP-PID航向控制器可以较好地跟踪弯曲航道计划航线,舵角和转向幅度均小于现有航迹控制器.

基于最大净功率输出的PEMFC阴极供气系统优化控制研究

通过建立质子交换膜燃料电池(PEMFC)阴极供气系统数学模型,分析空气压缩机电压和背压阀开度对系统净功率输出的影响;针对负载电流变化,研究PEMFC系统对应的最优过氧比和最优阴极压力,建立最大输出净功率-过氧比-阴极压力寻优表;考虑过氧比和阴极压力之间的耦合关系,基于辨识出的传递函数矩阵,设计针对空气压缩机电压和背压阀开度的前馈解耦控制器,优化氧气供给和压力控制,并进行相应的仿真验证。结果表明,所提解耦控制器能有效减小过氧比和阴极压力之间的耦合影响,在实现最大净功率闭环控制的同时,具有更快的响应速度和更小的超调量。

阵列天线装配工艺参数与其电磁性能的关联性

阵列天线作为机电强耦合产品,其物理特性覆盖了机械性能和电磁性能。传统的以经验参数为主的装配方式,因其过程缺乏科学控制,导致其电磁特性质量波动不可控。因此,开展阵列天线装配工艺参数与其电磁性能关联性研究,通过理论分析、仿真、样件试验等方法,明确了影响阵列天线电磁性能的工艺参数,再通过控制工艺参数,实现阵列天线装配后的电磁特性质量波动控制。

基于扰动观测器的永磁同步电机非奇异终端滑模控制

针对传统滑模控制中系统误差收敛速度缓慢以及系统固有抖振问题,采用一种自适应幂指数趋近律的非奇异终端滑模控制方法设计速度环控制器,在避免奇异现象的基础上实现系统误差快速收敛,提高了趋近速度并有效改善系统抖振问题。仿真结果表明基于滑模扰动观测器下非奇异终端滑模的控制策略有效提高了永磁同步电机控制系统的动态响应能力和鲁棒性。

结合瓶颈注意力的端到端机械臂视觉伺服研究

针对传统视觉伺服算法特征提取步骤繁琐、实时性能差的情况,提出了一种基于卷积神经网络的端到端直接视觉伺服算法,通过直接预测安装在机械臂末端相机的瞬时线速度与瞬时角速度来进行伺服定位工作,不需要标记手工特征、相机固有参数或深度信息。将相机观测到的图像输入改进的GhostNet轻量级特征提取网络进行信息提取,在网络中融入瓶颈注意力模块来增强目标物体的空间信息和通道信息;采用全连接层作为速度回归函数对线速度、角速度进行解耦回归;在真实环境下采用一种实时捕捉方法制作训练所需的数据集,速度标签根据基于位置的视觉伺服控制律算法生成,训练好的网络可使机械臂在未经训练的初始位姿下完成高效、精确的定位和跟踪任务。大量真实场景下的实验测试结果验证了该算法的有效性,且对场景背景信息具有一定的鲁棒性。

特厚煤层大断面软岩巷道底鼓治理措施与效果

以斜沟矿特厚煤层大断面软岩巷道反复强底鼓工程实际为背景,综合运用理论计算与现场监测方法,结合巷道底板岩层特性,判断巷道底鼓类型,引用巷道极限平衡理论,计算得出巷道极限平衡区最大深度为11.05 m,设计“双应力壳-梁”控制巷道底鼓措施。现场应用的监测结果表明,采用新的控制措施后,巷道底鼓量最大为17.49 cm,巷道底板围岩控制措施取得较好效果。

电火花多电极高效加工GH4169D闭式整体叶轮

叶轮是飞机发动机的重要核心零/部件之一,镍基高温合金GH4169D闭式整体叶轮是其中加工难度最大的一种。传统电火花加工(Electrical Discharge Machining,EDM)闭式整体叶轮,主要受限于加工效率低,成品率低。为此,创新研发了电火花多电极多变量自适应控制系统,根据加工过程中的放电状态和加工环境,自适应调节间隙电压、抬刀周期和脉冲间隔时间,既保证了多电极同时加工的条件,又可以维持高效加工的极间加工环境。在大能量放电条件下,采用多个电极同时加工闭式整体叶轮的多个流道型面;在小能量放电条件下,通过分步加工的方法,修整粗加工后的流道型面,这样既可以提高加工效率又可以满足加工表面质量的要求。实验结果显示,在多电极粗加工中,单个流道型面加工平均用时仅需17 min,相比单电极加工单个流道型面,效率提高了10倍左右。在多电极精加工中,叶盆和叶背表面粗糙度分别仅为1.246和1.487μm。该结果表明了电火花多电极多变量自适应控制系统可广泛应用于闭式整体叶轮的加工制造中,具有十分重要的意义。