非完整移动机器人的迭代学习控制

首先针对迭代初态偏移期望初态的情况,利用构造期望轨迹的办法给出了基于相对阶的迭代学习控制算法,然后借助于压缩映射原理与Gronwall-Bellman不等式给出了算法收敛性的证明.最后将得到的迭代学习控制律应用于非完整移动机器人的跟踪控制问题.MATLAB仿真结果表明了所给控制算法的有效性.     

初态偏移非线性系统跟踪控制的迭代学习算法

基于迭代学习控制理论提出一种新的可变增益学习控制算法,并对系统初态的迭代学习律进行了讨论,利用算子理论证明在非线性系统中存在初态偏移时经过迭代学习后,输出仍能跟踪期望轨迹;对其收敛性进行数学证明,得到谱半径形式的迭代学习律收敛的充分条件,从而解决了可变学习增益迭代学习控制的初态偏移问题.最后在注塑机注射速度控制系统中与增益不可变迭代学习算法进行比较,仿真结果验证了算法的有效性.     

网络控制系统中迭代学习控制算法的鲁棒收敛性分析

针对网络控制系统中受输入扰动和初态干扰的非线性系统,提出了一种迭代学习控制算法,讨论了输出数据丢失情况下系统输出对期望轨迹的跟踪问题。采用一个概率已知的随机贝努利序列来描述网络控制系统中的数据丢失现象,即如果输出数据没有丢失,则利用跟踪误差来修正上一次迭代学习时的控制量,从而获得系统当前控制量;如果存在输出数据丢失现象,则系统当前控制量保持上一次迭代时的控制量不变。给出了保证算法收敛的充分条件。从理论上证明了系统满足给定的收敛条件时,在数据丢失网络环境下具有输入扰动、初态扰动的被控系统随迭代学习次数的增加,系统输出除初始点以外都能够收敛于期望轨迹。通过仿真算例进一步验证了所提方法的有效性。     

基于边界层的一类不确定系统的迭代学习控制

针对一类具有任意初态和非周期有界扰动的不确定非线性时变系统,提出一种基于边界层的迭代学习控制方法,将边界层设计成一个具有剩余宽度的指数衰减函数,通过边界层把任意初态问题转换为零初值迭代学习问题.针对周期和非周期不确定性扰动,分别设计周期项的学习律和非周期项的边界学习律,然后在此基础上给出了迭代学习控制算法.文中给出了相关定理,并应用类Lyapunov方法给出了定理的详细证明.仿真结果表明,所提出的算法是有效的,轨迹跟踪误差能收敛到边界层.     

一种改进的非线性离散系统迭代学习控制算法

针对非线性离散时变系统的迭代学习控制问题,提出了一种改进的迭代学习控制算法。在新控制算法中,除了在传统算法基础上增加了状态补偿外,还引用了小波变换来对跟踪误差进行了滤波而没有相位补偿。利用该算法进行学习控制,使系统的实际输出以更快的速度收敛于系统的理想输出;并进一步从理论上证明了新算法的收敛性。     

迭代学习在多智能体编队中的控制研究

针对具有控制时延的非线性多智能体系统模型,设计了一种能够实现其稳定编队的迭代学习控制算法.首先,建立单个智能体的动态特性,根据多智能体的拓扑连接结构,将多智能体编队控制问题转化为跟踪问题.其次,针对每个智能体设计形式统一的迭代学习控制器,根据每个智能体不同的动态特性,选取合适的学习增益矩阵.最后,基于λ范数理论证明了算法的收敛性.由于该迭代学习控制算法放宽了对迭代初值的限定,使其达到在任意常值初态条件下的稳定控制,从而满足了各个智能体在初始位置随机分布时的编队控制要求.仿真结果证明了文中所给算法的有效性.     

非线性系统开闭环PID型迭代学习控制的收敛性分析

针对一类参数未知非线性的迭代学习控制问题提出了一种开闭环PID型迭代学习控制律,这种迭代学习律同时利用了系统当前的跟踪误差和前次迭代控制的跟踪误差修正控制作用,给出了迭代学习控制算法收敛的充分性条件.分析表明,所给出的迭代学习控制律推广了现有的结果.     

基于GPS的太阳跟踪系统优化设计研究

优化设计了一种基于新型控制模式和控制算法的槽式太阳能一维跟踪系统,以解决太阳能程序跟踪模式下累积误差增大、控制算法不精确、跟踪精度不高的问题.增加了GPS信号接收器和角度传感器模块,增强了跟踪过程中预防算法参数变动和恢复装置状态的能力;提出了添加多重修正系数的太阳方位角计算公式,采用MATLAB软件进行模拟仿真,并通过误差分析论证了该控制算法的正确性和优越性.在太阳能槽式集热系统中,此跟踪系统能够满足东西向的一维跟踪要求,理论跟踪精度达到0.1°,实验跟踪精度达到0.23°,具有跟踪精度高、安装简单、管理方便等优点.     

不确定时滞系统的PD型迭代学习控制算法

针对不确定时滞系统,在网络时滞范围已知情况下,采用改进PD型迭代学习控制算法补偿网络时滞.在初态是严格重复时,给出这类系统的极限轨迹和迭代输出收敛于该极限轨迹的充分条件.并与P型迭代学习控制算法进行比较.仿真结果表明改进后的PD型迭代学习控制算法能够有效地补偿此类时滞.当网络时滞范围变窄时,能够更加精确跟踪极限轨迹.在相同迭代次数情况下,PD型迭代学习控制算法比P型迭代学习控制算法能更快收敛于极限轨迹.     

非线性时变系统开闭环PI型迭代学习控制研究

讨论了一类非线性时变系统开闭环PI型迭代学习控制算法,该算法相对于开环、闭环PI型迭代学习算法不仅能较快地跟踪期望轨迹,而且能增强学习控制的鲁棒性。给出了仿真研究实例,仿真结果验证了该算法的有效性和优越性。     

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     

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