基于pH中和过程的模糊控制器设计与仿真

化工中和过程中pH值具有严重的非线性性,控制十分困难,模糊控制器能表现出迅速的响应和稳定性.笔者采用模糊控制器来控制这一复杂非线性过程,对pH 值中和过程进行了仿真,相比传统控制,能达到理想控制效果.     

全向移动机器人自抗扰解耦控制

针对全向移动机器人系统存在的模型复杂、强耦合以及内外随机扰动造成控制困难的问题,提出自抗扰控制方法.以八轮全向移动机器人为例,通过分析运动学、动力学模型,设计自抗扰解耦方法.以非线性函数作为自抗扰控制器各部分的状态反馈,采用扩张状态观测器估计内外随机未知扰动并给予主动扰动补偿.仿真试验表明:与传统PID控制器相比,经过解耦的自抗扰控制器对全向移动机器人具有较好的控制效果,能够抑制未知扰动,提高系统性能.     

永磁同步电机自抗扰控制研究

将自抗扰控制引入永磁同步电机的速度环控制中,为减少算法计算量和降低参数调整难度,对非线性自抗扰控制进行结构优化和线性化处理,完成永磁同步电机的线性自抗扰控制器设计和仿真分析.仿真结果表明,自抗扰控制较常规PI控制抗负载扰动能力强,对不同转速的运行具有较强适应性.     

基于自抗扰控制技术的单元机组协调系统

针对单元机组协调系统具有多变量强耦合、非线性及参数时变的特性,提出了基于自抗扰控制技术的单元机组协调系统控制方案.其主要特点是把每个通道的耦合环节看成该通道的外扰,通过自抗扰控制器中的扩张状态观测器对总扰动进行估计,并在控制信号中加以补偿,从而实现了单元机组的解耦控制.通过对一个通用的非线性协调系统模型的仿真研究,表明了该方案具有较好的解耦效果、较快的响应速度和较强的抗干扰能力.     

基于BP神经网络的三轴增稳云台自抗扰控制

针对三轴增稳云台伺服系统非线性特性,以及PD控制抗扰能力差,自抗扰控制器由于参数众多而导致整定过程耗时且费力的缺陷,本文利用BP神经网络的全局逼近能力和自我学习能力,将其与自抗扰控制器组成复合控制器,对自抗扰控制器的所有关键参数进行自整定寻优,应用于含Stribeck摩擦模型的三轴增稳云台伺服系统。仿真结果表明:该方法用于自动整定参数可行有效,与PD控制和参数固定的常规自抗扰控制器相比,具有更高的控制精度和更强的抗扰能力,对提高增稳云台的性能具有较好的应用价值。     

基于改进遗传算法的自抗扰控制器优化设计

针对超空泡航行体受力特征及其航行时具有非线性、时滞与耦合等复杂问题,提出可根据适应度对控制参数进行自适应动态调整的改进遗传算法。通过建立超空泡航行体纵向模型,设计专用自抗扰控制器对其进行控制,并针对控制器参数多、调节困难的问题,改进了自适应遗传算法对其精确优化。最后通过特性仿真,验证了基于改进的自适应算法的自抗扰控制器相比经典自抗扰控制器的优势。仿真结果表明,该自抗扰控制器符合实际需求,具有良好的控制效果。     

动力翼伞系统耦合补偿控制策略研究

动力翼伞系统是具有强非线性、强耦合特性的系统,其精确控制比较困难.动力翼伞系统具有两个控制通道,控制的难度在于纵向推力对下偏控制存在着非线性的强耦合作用,在受到风场干扰时会导致系统耦合加剧,从而在控制过程中引起较大偏差,甚至导致系统失速.本文提出了一种基于耦合补偿的自抗扰控制策略,并将该非线性耦合关系设计为扩张状态观测器中的已知扰动,从而提高了控制器的跟踪性能.在动态耦合补偿的基础上改进控制律,将非线性动力翼伞系统设计成易于控制的独立积分器,从而提高横向轨迹跟踪控制器的抗干扰性和控制跟踪性能.通过仿真实验可验证该控制策略优于传统的自抗扰控制（active disturbances rejection controller,ADRC）和PID控制.      

深海船舶动力定位的动态面复合自抗扰控制

以自抗扰控制为基础,针对其非线性状态误差反馈控制律和扩张状态观测器分别引入动态面控制及线性自抗扰控制思想进行适应性改造,设计出一种运用于船舶动力定位的动态面复合自抗扰控制器。改进的非线性状态误差反馈控制律是为了提高系统对扰动的估计能力,线性扩张状态观测器是为了在估计扰动的同时对参数的选取进行简化。仿真结果表明,改进后的动态面复合自抗扰控制器有更好的抗干扰能力,对目标值的调节时间更快,鲁棒性更强,提升了船舶动力定位的精准度。     

非线性自抗扰状态PI控制器的研究

针对线性状态PI控制器只适用于单输入单输出的线性系统的不足 ,提出了非线性自抗扰状态PI控制方法 ,将“自抗扰”控制技术的控制思想应用于常规状态PI控制 ,使其适用于单输入单输出的非线性系统的控制。解决了“自抗扰”控制技术中扩张状态观测器的参数问题 ,并对系统的稳定性进行了定性分析。仿真算例表明 ,非线性自抗扰状态PI控制器对对象模型参数摄动和外扰具有良好的适应性和鲁棒性     

非线性自抗扰状态PI控制器的研究

针对线性状态PI控制器只适用于单输入单输出的线性系统的不足,提出了非线性自抗扰状态PI控制方法,将“自抗扰”控制的控制思想应用于常规状态PI控制,使其适用于单输出的非线性系统的控制,解决了“自抗扰”控制技术中扩张状态观测器的参数问题,并对系统的稳定性进行了定性分析,仿真算法表明,非线性自抗扰状态PI控制器对对象模型参数摄动和外扰具有良好的适应性和鲁棒性。     

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     

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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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