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   

Adaptive distributed convex optimization for multi-agent and its application in flocking behavior     

Zhengquan Yang  Qing Zhang  Zengqiang Chen 《Journal of The Franklin Institute》2019,356(2):1038-1050

This paper studies adaptive optimization problem of continuous-time multi-agent systems. Multi-agents with second-order dynamics are considered. Each agent is equipped with a time-varying cost function which is known only to an individual agent. The objective is to make multi-agents velocities minimize the sum of local functions by local interaction. First, a distributed adaptive algorithm is presented, in which each agent depends only on its own velocity and neighbors velocities. It is indicated that all agents can track the optimal velocity. Then we apply the distributed adaptive algorithm to flocking of multi-agents. It is proved that all agents can track the optimal trajectory. The agents will maintain connectivity and avoid the inter-agent collision. Finally, two simulations are included to illustrate the results.  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   

高等几何的群论观点对初等几何的指导作用     

杜家安  刘林安 《安阳师范学院学报》2001,(5):53-55,62

本文从仿射变换，仿射性质、仿射量，仿射对应图形入手，通过实例，分析、探讨高等几何的群论观点对于初等几何的指导作用，在较高层面上认识几何空间的基本特性、研究方法、内在联系、确认几何学的本质，以便更深入地认识和掌握初等几何，指导初等几何的教学与研究，居高临下地认识初等几何的内涵与外延。同时，进一步认识到高等几何不仅在提高观点方面具有独特作用，而且在论证方法，思考问题等方面具有独特的巧妙、灵活等特点。  相似文献   

英语习语的来源及英汉对应关系     

赵海龙 《鸡西大学学报》2006,6(5):53-55

在任何一个具有悠久历史的国度,习语都是它民族文化的一颗璀璨明珠。习语以其搭配的语法形式,深刻丰富的语义内容得到了人民群众的厚爱,也引起了许多作家的浓厚兴趣。恰当的运作习语可使语言增添文采和感染力,使文章更具魅力。英语习语范围广泛,寓意深刻,本文将从英语习语的来源及英汉对应关系两方面进行探讨。  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   

浅议第二语言教学中的听力理解     

郭峥嵘 《太原教育学院学报》2004,22(2):47-50

听，作为语言活动的一种形式和层面，作用不可忽视。随着英语教学改革的不断深入发展，听力能力的提高成为当前英语墩学的首要目标。通过对言语听辨的不同类型、听力材料的语篇衔接及听力理解过程的本质等问题进行理论探讨．可找到影响第二语言听力理解教学的因素及解决方法。  相似文献