电动客车电动助力转向回正控制策略

以增强电动客车电动助力转向系统(EPS)的回正性能为目标,提出了模糊自整定PID回正控制策略.以转向盘转角传感器和转向盘转速传感器获取的转角和转速信号为控制信号,采用模糊自整定PID方法进行回正控制,输出回正控制电压,使助力电机将转向盘迅速带到中位.综合模糊控制和PID控制的双重优点,设计了模糊PID控制器,根据所设计...     

循环球式EPS系统助力特性控制策略研究

研究电动大客车电动助力转向(EPS)系统助力特性控制策略.采用优化设计方法,开发了适合纯电动大客车EPS系统使用的循环球式电动助力转向器,并建立了其动力学模型;针对EPS系统对系统鲁棒稳定性和动态特性的要求,提出了"上层混合H2/H∞电流决策控制 下层模糊PID电流跟踪控制"的两层助力特性控制策略.仿真结果表明:应用上层混合H2/H∞电流决策控制,EPS系统可有效获得来自路面的低频信息并抑制路面高频干扰,使驾驶员获得满意的路感;应用下层模糊PID电流跟踪控制,EPS系统具有较好的动态特性,能够对目标电流进行准确跟踪,使驾驶员获得理想的助力特性.     

锅炉汽包水位自整定模糊PID控制

锅炉汽包水位是一种非线性、时变大、强耦合的多变量系统.在建立锅炉汽包水位调节系统的基础上,运用自整定模糊PID控制对汽包水位进行控制.并对控制器的设计进行仿真分析,结果表明自整定模糊PID控制改善了汽包水位控制系统的静、动态特性,从而实现了对锅炉汽包水位的最佳实时控制.     

自动加药系统中模糊自整定PID控制方法的研究

提出利用模糊自整定PID控制器实现自动加药的方法,将控制器和PID控制器结合在一起,利用模糊逻辑控制实现了PID控制器参数在线自调整,完善了传统PID控制器的性能,提高了系统的控制精度.并把MATLAB中的Fuzzy Toolbox和Simulink结合起来,方便实现了自整定模糊PID控制系统的计算机仿真.仿真结果表明模糊自整定PID对被控系统的适应性强,鲁棒性好,超调小,反应时间快,能很好地适应现实生产过程中的控制要求.     

基于模糊PID参数自整定真空冶炼炉温度控制系统的研究

内热式蒸馏真空冶炼炉采用先进的工艺技术,是研制新材料和有色金属冶炼的重要设备.其温度控制系统具有非线性、时变性和滞后性等特性,严重影响温度控制的快速性和准确性.本文采用了模糊PID参数自整定控制方法,用模糊控制规则对PID参数进行修改,利用Mat-lab仿真建模,结果表明,模糊PID参数自整定控制对冶炼炉温度控制效果明显更好,具有响应速度快、几乎无超调的优点,又提高了系统的控制精度.     

在线参数自整定模糊PID控制器的设计与仿真

根据模糊控制原理,设计了一种参数自整定PID控制器.借助于MATLAB的系统仿真软件Simulink,实现了对模糊PID控制系统的仿真,仿真结果显示模糊PID控制系统具有超调小、稳态控制精度高等特点.     

直流电动机人工智能控制器研究

将PID控制和模糊控制相结合,控制直流电动机.首先对直流电动机的PID控制进行仿真,鉴于其参数变化范围大,整定过程繁锁,所以采取遗传算法对PID参数进行整定.通过仿真发现,整定过程大大简化,然后又采用模糊自整定方法对直流电动机进行控制.最后,将各种控制方案进行仿真,结果进行对比分析,表明模糊自整定控制器不仅具有良好的动、静品质,且具有较强的抗干扰能力以及参数时变的适应能力.     

基于参数自整定模糊PID的加热板温控系统研究

针对具有滞后特性的温度控制系统,本文设汁了一种用于加热板温控系统的参数自整定模糊PID控制器,它利用模糊控制规则对PID参数自动整定.通过仿真表明这种控制器对温控系统模型的适应性较强,有很好的鲁棒性和控制效果,将其用于大部分大功率加热设备,能达到零超调、调节时间快且稳态误差也非常小的理想效果.     

基于遗传算法的模糊自整定双环直流调速系统

将遗传算法与模糊控制相结合,针对工程上通常采用直流调速系统,详细分析双闭环调速系统的模糊自整定PID控制,设计了模糊控制器并对直流双闭环调速系统进行建模.对系统的转速环的动态性能、抗干扰性能进行仿真分析.最后,与传统PID控制进行比较,得到模糊自整定控制可以大大提高控制效果、抗扰性能强、系统响应速度快、动态性能好等优点.     

串联谐振全桥逆变电路自适应模糊PID恒功率输出研究

系统采用自适应模糊PID控制技术,针对串联谐振全桥逆变电路,利用MATLAB建立了系统自适应模糊PID输出功率控制仿真模型,并给出了电路仿真波形.结果表明,系统采用自适应模糊PID控制方法,能够应用模糊控制技术对PID参数进行在线修改,以满足不同时刻的功率偏差和偏差变化率对PID参数自整定的要求,使被控对象具有良好的动、静态性能,实现逆变电路的恒功率输出控制.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with