Fractional order sliding mode control of a pneumatic position servo system     

Hai-Peng Ren  Xuan Wang  Jun-Tao Fan  Okyay Kaynak 《Journal of The Franklin Institute》2019,356(12):6160-6174

Gas flow has fractional order dynamics; therefore, it is reasonable to assume that the pneumatic systems with a proportional valve to regulate gas flow have fractional order dynamics as well. There is a hypothesis that the fractional order control has better control performance for this inherent fractional order system, although the model used for fractional controller design is integer order. To test this hypothesis, a fractional order sliding mode controller is proposed to control the pneumatic position servo system, which is based on the exponential reaching law. In this method, the fractional order derivative is introduced into the sliding mode surface. The stability of the controller is proven using Lyapunov theorem. Since the pressure sensor is not required, the control system configuration is simple and inexpensive. The experimental results presented indicate the proposed method has better control performance than the fractional order proportional integral derivative (FPID) controller and some conventional integral order control methods. Points to be noticed here are that the fractional order sliding mode control is superior to the integral order sliding mode counterpart, and the FPID is superior to the corresponding integral order PID, both with optimal parameters. Among all the methods compared, the proposed method achieves the highest tracking accuracy. Moreover, the proposed controller has less chattering in the manipulated variable, the energy consumption of the controller is therefore substantially reduced.  相似文献   

Advanced stability criteria for linear systems with time-varying delays     

M.J. Park  O.M. Kwon  J.H. Ryu 《Journal of The Franklin Institute》2018,355(1):520-543

This paper investigates a stability problem for linear systems with time-varying delays. By constructing suitable augmented Lyapunov–Krasovskii functionals, improved stability criteria under various conditions of time-varying delays are derived within the framework of linear matrix inequalities (LMIs). Moreover, to reduce the computational burden caused by the non-convex term including h²(t), how to deal with it is applied by estimating it to the convex term including h(t). Finally, three illustrative examples are given to show the effectiveness of the proposed criteria.  相似文献   

A decentralized control method for frequency restoration and accurate reactive power sharing in islanded microgrids     

Zhanqiang Zhang  Chunxia Dou  Dong Yue  Bo Zhang  Wei Luo 《Journal of The Franklin Institute》2018,355(17):8874-8890

To achieve the frequency restoration (FR) and accurate reactive power sharing (RPS) in islanded microgrids (MGs), an improved P-f droop control is proposed. Firstly, the inverter impedance, whose value is set by the virtual impedance method, is used to minimize the impact of line resistance on powers coupling and RPS. Then, in order to restore the frequency of distributed generations (DGs) to the rated value, the reference is changed for compensating the frequency deviation (FD) caused by loads change. And the fast FR rate is achieved under a large constant k. Besides, in order to eliminate the inaccuracy of RPS caused by voltages difference (VD), the line voltage drop (LVD) is used to compensate the voltage droop characteristics. The use of voltage feedback ensures that the obtained voltage is desired after the LVD compensation. Finally, the simulation in RT-LAB indicates the effectiveness of proposed method in an islanded MG model.  相似文献   

我国计算机科学研究队伍低龄化表现的数量特征   总被引：4，自引：1，他引：4  

郭永正  梁立明等 《研究与发展管理》2001,13(2):47-51,73

对《计算机研究与发展》、《软件学报》和《计算机学报》所记录的5024个作者年龄数据进行了科学计量学分析,发现了我国计算机科学研究队伍低龄化表现的三个数量特征：青年峰突兀老年峰平缓的双峰年龄分布;青年作者比例增大与第一作者平均年龄逐年降低的趋势;第一作者低龄化及各序位作者平均年龄依次后移而递增的合作模式。  相似文献   

《科学学研究》2001-2003年载文、作者和引文的统计分析   总被引：19，自引：0，他引：19  

颜志森 《科学学研究》2004,22(5):557-560

应用文献计量学的方法,对2001-2003年共16期《科学学研究》作了定量分析,并与相关文献进行比较。结果表明:该刊载文量适中,基金项目论文占37.50%;平均出版时滞165天,共有31篇载文的出版时滞仅为3个月;论文合著率60.51%,合作度1.85,该刊稿源丰广,又拥有一批核心作者和核心作者群;第一作者中具有高级职称的占58.97%,博士和博士研究生占42.17%,年龄31～40岁的占43.80%;篇均引文9.07条,引文种类多样,质量上乘。  相似文献   

2000～2005年《青岛职业技术学院学报》载文及作者统计分析   总被引：1，自引：1，他引：1  

刘卫华  王长中 《青岛职业技术学院学报》2006,19(3):56-61

运用文献计量学的统计方法，对2000-2005年出版的《青岛职业技术学院学报》（2000-2002年原刊名为《青岛教育学院学报》）从学报的载文量及篇密度，作者年龄、职称、性别，作者地域分布，载文分类比较等方面进行统计，分析该刊6年来的发文特点及载文作者的总体状况，以期为学报今后的发展找出方向。  相似文献   

是文责自负还是文责共负   总被引：3，自引：0，他引：3  

王秀中 《辽宁师范大学学报(社会科学版)》2002,25(2):62-63

责自负这一传统的编辑准则有缺陷：夸大了作的责任；编辑的权利与责任失衡；淡化了出版部门的责任感；责自负在约束作的同时，却忽略了对编辑出版的责任。应该建立一种以作为主，编辑出版为辅，共同对读、社会负责的新的编辑准则。  相似文献   

2012—2014年F5000农业科学类论文来源及作者的文献计量学分析     

马秋明  窦春蕊  温晓平 《中国科技期刊研究》2016,27(8):818-824

【目的】对2012—2014年F5000中农业科学类论文的来源及作者进行文献计量学分析。【方法】筛选2012—2014年入选F5000的农业科学类论文,通过中国知网对其相关信息进行完善,利用EXCEL2007对论文的来源及作者信息进行统计与分析。【结果】共选出829篇论文,来自188家单位,其中中国科学院、中国农业科学院等23家高产单位共产出530篇。该类论文主要发表于少数知名度较高的中国精品科技期刊;北京和江苏产出的论文篇数远大于其他省区。论文的合著率为97.47％,合作度为4.999,20～30岁的硕士、博士作者是其核心作者群体。【结论】明确了2012—2014年F5000中农业科学类论文的来源和作者概况,为农业科技期刊编辑同仁组约高水平研究论文提供了方向。  相似文献   

《情报杂志》2003年、2004年载文统计分析   总被引：2，自引：0，他引：2  

纪绍平 《现代情报》2005,25(12):148-150

本文对《情报杂志》2003年、2004年载文情况进行统计分析，归纳出特点，得出该刊近两年发展的规律。为进一步办好刊物提供依据。  相似文献   

近代词人生卒年及事迹丛考——兼订《清人诗文集总目提要》《近代词人考录》等诸书     

刘欢萍 《南阳师范学院学报》2011,10(2):49-52

近代诗词作者辈出,目前学界对他们生卒年岁的研究成果卓然。然而笔者在拜读前贤诸著之余,仍发现不少词人的生卒年存在着各种各样的歧异与缺失。故不揣愚钝,谨据词人别集及相关史料,就陈祖善、廷奭、周茂榕等若干知名词人的生卒年岁作进一步考辨,以期于近代诗词研究提供些许助益。  相似文献