Backstepping-based distributed coordinated tracking formultiple uncertain Euler-Lagrange systems

Based on the idea of backstepping design, distributedcoordinated tracking problems under directed topology are discussedfor multiple Euler-Lagrange （EL） systems. The dynamicleader case is considered. First, with the parameter-linearity property,a distributed coordinated adaptive control scheme is proposedfor EL systems in the presence of parametric uncertainties.Then, subject to nonlinear uncertainties and external disturbances,an improved adaptive control algorithm is developed by usingneural-network （NN） approximation of nonlinear functions. Bothproposed algorithms can make tracking errors for each followerultimately bounded. The closed-loop systems are investigated byusing the combination of graph theory, Lyapunov theory, and BarbalatLemma. Numerical examples and comparisons with othermethods are provided to show the effectiveness of the proposedcontrol strategies.

Distributed tracking for networked Euler-Lagrange systems without velocity measurements

The problem of distributed coordinated tracking control for networked Euler-Lagrange systems without velocity measurements is investigated. Under the condition that only a portion of the followers have access to the leader, sliding mode estimators are developed to estimate the states of the dynamic leader in finite time. To cope with the absence of velocity measurements, the distributed observers which only use position information are designed. Based on the outputs of the estimators and observers, distributed tracking control laws are proposed such that all the fol- lowers with parameter uncertainties can track the dynamic leader under a directed graph containing a spanning tree. It is shown that the distributed observer-controller guarantees asymptotical stability of the closed-loop system. Numerical simulations are worked out to illustrate the effectiveness of the control laws.

Cooperatively surrounding control for multiple Euler–Lagrange systems subjected to uncertain dynamics and input constraints

In this paper, we investigate cooperatively surrounding control （CSC） of multi-agent systems modeled by Euler- Lagrange （EL） equations under a directed graph. With the consideration of the uncertain dynamics in an EL system, a backstepping CSC algorithm combined with neural-networks is proposed first such that the agents can move cooperatively to surround the stationary target. Then, a command filtered backstepping CSC algorithm is further proposed to deal with the constraints on control input and the absence of neighbors＇ velocity information. Numerical examples of eight satellites surrounding one space target illustrate the effectiveness of the theoretical results.

Cooperative impulsive formation control for networked uncertain Euler–Lagrange systems with communication delays

This paper investigates the cooperative formation problem via impulsive control for a class of networked Euler–Lagrange systems. To reduce the energy consumption and communication frequency, the impulsive control method and cooperative formation control approach are combined. With the consideration of system uncertainties and communication delays among agents, neural networks-based adaptive technique is used for the controller design. Firstly, under the constraint that each agent interacts with its neighbors only at some sampling moments, an adaptive neural-networks impulsive formation control algorithm is proposed for the networked uncertain Euler–Lagrange systems without communication delays. Using Lyapunov stability theory and Laplacian potential function in the graph theory, we conclude that the formation can be achieved by properly choosing the constant control gains. Further, when considering communication delays,a modified impulsive formation control algorithm is proposed, in which the extended Halanay differential inequality is used to analyze the stability of the impulsive delayed dynamical systems. Finally, numerical examples and performance comparisons with continuous algorithm are provided to illustrate the effectiveness of the proposed methods.

Dynamics and Proportional-derivative Control of 3-link Planar Manipulator

In this paper, an effective dynamic equation of a three link manipulator for a control purpose has been dealt with by the Euler-Lagrange method. The structural properties of the derived dynamic equation were proved so that the vast control strategies developed for the serial counterparts can be easily extended for controlling the three link manipulator. In addition, it is illustrated how to design a PD controller for the robot manipulator by making use of computed torque method strategy to develop our controller. Simulation results are included in order to depict the performance of the controller.

Trajectory Tracking Control of Euler-Lagrange Systems with ISS-Like Robustness to Actuator Noises

This paper studies global robust tracking of uncertain Euler-Lagrange systems with input disturbances.The authors develop a robust regulation-based approach for the problem.Specifically,by introducing a novel nonlinear internal model,the authors solve global asymptotic trajectory tracking with disturbance rejection of multiple step/sinusoidal signals with unknown amplitudes,frequencies,and phases.Moreover,the authors show that a robustness property to actuator noises can be guaranteed in a sense of strong integral input-to-state stability(iISS).That is,the closed-loop system is not only i ISS but also input-to-state stable(ISS)to small magnitude actuator noises.Furthermore,the authors explore a by-product overparametrized linear regression estimation,coming up with robust estimation of the unknown parameters.Finally,the authors present several numerical examples to illustrate the theoretical results.

Interconnection and damping assignment and Euler-Lagrange passivity-based control of photovoltaic/battery hybrid power source for stand-alone applications

A DC hybrid power source composed of photovoltaic cells as the main power source,Li-ion battery storage as the secondary power source,and power electronic interface,is modeled based on port-controlled Hamiltonian systems and Euler-Lagrange framework.Subsequently,passivity-based controllers are synthesized.Local asymptotic stability is ensured as well.In addition,a power management system is designed to manage power flow between components.Modeling and simulation of the proposed hybrid power source is accomplished using MATLAB/Simulink.Our interest is focused on the comparison of the two passivity-based control methods and their use in hybrid power systems.

小反刍兽疫在中国的流行趋势及应对措施

小反刍兽疫是由小反刍兽疫病毒感染小反刍兽的一种严重的急性、烈性、接触性传染病,以高热、口炎、胃炎、腹泻和肺炎为特征。该病呈全球性自西向东流行趋势,我国目前已有9省市发生该疫情,其他省份防控局面也颇为严峻,对我国畜牧业发展造成了极其严重的影响。论文对小反刍兽疫在中国流行趋势进行分析,并提出相应的防控措施。

我国小反刍兽疫疫情现状与防控策略

小反刍兽疫作为重要的跨境动物疫病之一,已经传入我国并广泛流行。对我国养羊业、民生和经济发展造成沉重的打击。为有效防控该病,从小反刍兽疫的病原学、宿主范围,传播特点、传播因素和综合防控的策略等方面进行了概述,重点从制度保障和防控要素方面进行分析,旨在为我国小反刍兽疫的防控提供理论支持。

小反刍兽疫的流行、诊断与防控

小反刍兽疫是一种传染性极强的病毒性疾病,主要影响家养及野生的小反刍动物。该病的主要特征是发热、口腔炎、结膜炎、肠胃炎和肺炎,是世界动物卫生组织(World Organization for Animal Health,OIE)规定必须上报的疾病之一。文章对该病的流行与传播、诊断方法及防控措施进行了综述。

重复控制补偿的有源电力滤波器无源控制

针对基于欧拉-拉格朗日(Euler-Lagrange,EL)模型的有源电力滤波器(active power fil-ter,APF)无源控制方法在受到数学模型不精确、系统参数摄动等干扰情况下稳态跟踪精度欠佳的问题,根据APF的基本原理,对基于EL模型的APF无源性控制规律进行数学推导表明:依靠系统自然阻尼收敛的APF无源性控制律相当于引入前馈和解耦的开环控制方法;向系统注入阻尼的APF无源控制规律相当于在引入前馈和解耦的开环控制基础上加入了比例反馈控制,因此无法实现对期望平衡点的无静差跟踪和系统中"死区效应"等周期性干扰的抑制。为了提高APF无源控制的稳态跟踪精度,提出利用重复控制补偿的APF无源性控制方案。仿真和实验表明所提方法保留了原方法动态响应速度快等优点的同时提高了系统的稳态跟踪精度和干扰情况下的鲁棒性。

中国西藏小反刍兽疫的发生状况与防控

2007年7月,我国首次在西藏自治区阿里地区发生了小反刍兽疫疫病流行。从2007年7月9日到11月15日,先后在阿里地区革吉、日土、札达、改则4个县出现疫情,共20个疫点,羊发病6 122只,死亡1 888只。2008年6月,在那曲地区尼玛县双湖区再次发现小反刍兽疫疫情,病羊及同群羊合计6 690只。为消灭该病,采取了扑杀、大规模免疫、检疫和移动控制、疫源追溯和监测、野生动物控制及其他风险控制等一系列措施。阿里和那曲地区共有111 967只发病及同群绵羊和山羊被扑杀。对全自治区2 200多万只绵羊和山羊进行了免疫。作者对此次西藏小反刍兽疫疫情的诊断、临床症状、病理学变化、流行病学特点进行了报告,对2007年至2010年西藏自治区小反刍兽疫防控工作进行了总结。

可扩展工作流模型的信访业务协同处理系统

根据可定制业务流程和信息安全访问控制的需求,提出了一种可扩展动态工作流的协同处理模型。用户可以按照任务处理环节的需求以工作流子模型为核心定制任务中的活动类型和业务处理逻辑,定制各种附加子模型的业务知识与规则,并将基于角色和任务的访问控制运用于模型中,实现安全访问控制的工作流建模。利用该模型,研发了信访业务协同处理系统,介绍了系统的动态工作流管理技术、基于角色和任务的工作流访问控制与协调处理方法、以及基于任务授权控制的监控机制。三年多的应用情况证明,该系统在系统维护、协同处理、以及监控异常方面,具有应用优势。

重复控制与积分正反馈组合的磁轴承低功耗控制

本文提出一种重复控制与积分正反馈相结合的控制方法,以抑制磁轴承系统功耗。首先建立了磁轴承系统的数学模型,分析了由重力、转子不平衡和位移传感器噪声引起的电流噪声的频率特性,分析发现其可分为直流和多谐波两大类;其次推导了用于消除直流电流的控制器需满足的条件,在此基础上,设计了一种电流积分正反馈算法。通过调节转子的悬浮位置,利用混合磁轴承中永磁体产生的磁力抵消重力,抑制电流的直流分量,采用根轨迹方法确定保证闭环系统稳定的参数取值范围;然后提出一种嵌入式重复控制方法抑制转子不平衡和位移传感器引起的多谐波电流噪声,采用重构谱理论判定系统的稳定性。最后以磁悬浮控制力矩陀螺为测试平台,对所提出的控制算法进行仿真和实验研究。结果表明:采用该算法后,电流的直流分量基本被抑制,谐波分量的峰峰值减小了88.3%,功耗减小了7W,验证了该算法的有效性。

小反刍兽疫研究概况

小反刍兽疫是一种以发热、肺炎、口腔炎、结膜炎、肠胃炎为特征,主要感染山羊、绵羊等动物的急性、高度接触性传染病。我国农业部将其列为一类动物疫病,世界动物卫生组织将其定为必须通报的重要动物疫病。该病具有高发病率和高死亡率等特点,曾给很多国家的养羊业造成了巨大的经济损失。本文从该病的病原学、流行病学、临诊症状、发病机理、病理变化、诊断方法与防控措施等几个方面进行了综述,以期为广大兽医工作者对该病的有效防控提供有益的参考。

小反刍兽疫的流行、诊断与防控

小反刍兽疫是一种传染性极强的病毒性疾病,主要影响家养以及野生的小反刍动物。该病的主要特征是发热、口腔炎、结膜炎、肠胃炎和肺炎。小反刍兽疫也是世界动物卫生组织(OIE)规定必须上报的法定疾病之一。文章对该病的流行、传播方式、诊断方法以及防控措施进行了综述。

小反刍兽疫概述

本文就小反刍兽疫的病原学、流行病学、临床诊断、实验室诊断、综合防控等方面进行了全面的概述,以期对小反刍兽疫的防控工作提供帮助。

羊的小反刍兽疫疫情处置与防控体会

新疆霍城县兽医站于2013年11月26日接到三宫乡兽医站疫情上报后立即组织相关技术人员赶赴现场,对发病羊的发病原因进行调查,并采集样本送新疆动监所确诊。最后经农业部青岛兽医研究所确诊为小反刍兽疫。确诊后,霍城县人民政府根据有关"法律、法规、条例和应急预案"立即启动《霍城县重大动物疫情应急预案》,根据农业部专家组指定的《关于霍城县小反刍兽疫疫区动物屠宰淘汰处理的指导性意见》,按照"早、快、严"的原则,及时的扑灭了该次疫情。疫病虽然扑灭,但给我们留下了惨痛的教训,我们进行了深刻的反思和总结。

羊小反刍兽疫防控关键技术研究进展

小反刍兽疫是一种由副黏病毒科麻疹病毒属的小反刍兽疫病毒感染引起的传染病,该病主要在羊群中传播,该病一旦在羊群暴发,病死率可高达50%~100%,因此又称为羊瘟。当前,在我国周边的阿富汗、印度、巴基斯坦等国家,小反刍兽疫常呈流行性发生,国内的新疆等地是易发生该病的地区,该病的发生和流行给各个发展中国家的养羊业带来了严重的经济损失。论文主要介绍了小反刍兽疫的检测方法和疫苗研究进展,重点介绍了疫苗在小反刍兽疫防控中的重要性以及疫苗免疫程序的制定,以期为羊场小反刍兽疫的净化提供参考。

小反刍兽疫的防治

小反刍兽疫是以发热、口炎、腹泻、肺炎为特征的急性接触性传染病。介绍了宁夏首例小反刍兽疫发生的基本情况,针对疫病发生特点采取了隔离封锁、排查监测、消毒免疫等综合防控措施,取得较好的防控成效。