基于WebGIS的病虫害防治系统

设计了基于WebGIS的DIPS系统的体系结构,阐述了构件模型管理子系统的结构原理与维护方法。提出了适合WebGIS系统的通用接口标准,并设计出接口构件模型。给出病虫害防治系统中智能决策推理模块的设计思路和实现方法。通过DIPS系统的运行,验证了设计思路的正确性。     

汽车综合性能检测线软件系统的远程诊断与维护技术

在分析研究汽车综合性能分布式网络测控系统结构及工作原理的基础上,采用基于拨号网络和基于专线入网两种方式的远程控制技术,研究并实现了对汽车综合性能检测线软件系统的远程诊断与维护。论文对实际的远程诊断与维护系统的整体设计思路与具体实现方法进行了详细的分析和论述。应用情况表明,采用该方法开发研制的远程诊断与维护系统能够较好地满足汽车综合性能检测线微机测控系统的实际使用需要。     

基于Visual C++环境下的叶轮CAD系统设计

本文在 Visual C 环境下开发了一个渣浆泵叶轮设计的可视化 CAD系统。该系统按照软件工程的设计方法进行了程序系统的设计 ;系统采用可视化编程语言—Visual C 6.0编写 ;建立了便于维护与更新的叶轮设计数据库 ;该系统能根据设计结果自动生成工程图纸。该软件界面友好 ,易于使用 ,具有较强的实用性。     

数控机床功能部件可靠度建模与维护预警系统开发*

为了提高机床可靠性,深入分析了机床功能部件故障数据,研究了采用两重威布尔分段模型建立机床功能部件可靠度分布模型的方法与极大似然方法确定模型参数的过程。提出了基于可靠性分析的机床维护预警系统开发,阐述了预警系统原理设计过程与功能模块设计方法。系统的实例应用表明,该方法对机床预防维护非常合理有效。     

网上药品招标系统信息维护子系统的设计与实现

文章结合网上药品招标系统信息维护子系统的设计,阐述企业级电子商务系统信息维护子系统的设计与实现,重点介绍了信息维护子系统用户权限管理的实现。     

机载蓄电池地面维护系统自检方法研究

基于机载蓄电池地面维护目标,针对维护系统自身的自检问题,为了保证系统的可靠性、稳定性以及精度,研究了维护系统的自检测方法。以电控柜中常用部件继电器、数字电源、电子负载、电压表为主要检测对象,基于回路设计与返回值的思想,结合计量功能,完成维护系统的自检功能设计与实现。实验结果及现场应用表明,该方法自检成功率达到100%,维护电压、电流精度指标均在0.3%以内,单通道融入自检的维护过程所需时间在1s以内,满足机载蓄电池地面维护现场需求,有效保证维护设备自身的可靠性。     

大型机载数据链系统箱内测试的研究与实现

随着各种电子系统的大量使用,其日常维护任务日益加重,维护人员的大部分精力都消耗在定期维护测试中,维护效率低下已成为制约电子系统正常使用的重要因素之一;现以某大型机载数据链系统为研究背景,结合其自身工作特点和设计经验,将箱内测试技术与机内测试技术相结合,设计实现了该大型机载数据链系统的箱内测试;通过实验实践和使用维护证明,对该大型机载数据链系统使用箱内测试技术有效提高了系统的维护效率和维护工作便捷性,实现了全寿命周期内大幅缩减设计和使用维护成本的目的.     

基于O-O生命周期法的复杂系统设计方法

本文提出了一套基于面向对象生命周期法的复杂系统的工程化分析、设计与开发的原 则、方法和步骤,并应用于移动机器人控制平台的开发中．该方法为复杂系统的设计与开发 提供了明确的指导路线,可以提高整个系统的开发效率,并增强其可靠性、适用性和可维护 性．     

Web技术支持下的远程教育系统实现

介绍了Web服务技术应用于现代远程教育系统的可行性和优点,以及应用Web服务技术开发现代远程教育系统的设计思路、体系结构、实现方法和特点。有效地解决了跨平台使用、动态分布式管理和自动维护等问题,并且极大地降低了系统的开发与维护成本,为远程教育系统的发展注入了新的活力。     

基于Web的仓库管理系统的设计与实现

通过对传统仓库管理系统的不足的分析,提出了将web开发技术应用到仓库管理系统的设计与开发中的方法。按照这个思路,对系统进行了设计,最后采用JSP SQLServer2000的方式对该系统进行开发,并以出入库维护模块为例介绍了系统实现的主要方法。     

基于西门子S7-300PLC的风电机组专用变桨距控制系统设计

本文介绍了一种基于西门子S7-300 PLC的风电机组专用变桨距控制系统.详细介绍了系统的硬件设计和软什模块架构,在上位机调试环境上进行了控制精度和低电压穿越功能测试,并在整机试验平台上完成了联机调试.实验结果表明,该控制系统性能稳定,功能可靠,控制精度高,满足风电机组在不同风速下始终保持最佳转换效率、输出功率维持最大...     

Nonlinear controllers for solar thermal plants: A comparative study

Solar plants have nonlinear dynamics which must be taken into account when a control system is applied to them. The main purpose of the control systems is to maintain the outlet temperature in a desired reference value and, at the same time, attenuate the undesirable transients caused by the disturbances. Linear controllers, like PID ones, are not able to obtain good performance over the whole operation range of these kind of plants. To overcome these limitations two nonlinear controllers, a nonlinear model-based predictive controller and a distributed sliding mode controller, are applied to a solar plant in this work. The performance of these controllers is tested through experimental and simulation results, which show the tracking and disturbance rejection capabilities of the proposed controllers.     

Adaptive dynamic surface control of nonaffine nonlinear system with time‐varying state constraints

This paper investigates the problem of adaptive dynamic surface control for pure‐feedback time‐varying state constrained nonaffine nonlinear system. A continuous and semibounded condition is proposed of nonaffine function to ensure that the system can be controlled, and the invariant set is introduced for this mild condition. By employing the dynamic surface control technique, the “complexity explosion” problem caused by backstepping technique is averted in developed control method. Robust compensators are devised to weaken poor effect of disturbances and uncertainties. The time‐varying barrier Lyapunov functions are adopted to dispose the problem of time‐varying state constrains. Moreover, it is proved that the whole closed‐loop signals are bounded, the tracking error can converge to a small neighborhood of zero, and the system states are insured to maintain in the predefined compact sets. Finally, some simulation results are provided to demonstrate the effectiveness of the proposed method.     

A modified direct torque control with fault tolerance

The use of inverters in induction motor control has reduced classical motor faults, such as broken rotor bars or windings short-circuit, besides improving control performance. The control becomes faster and more precise, reducing peaks in current and torque, so that the motor can have a softer operation. On the other hand, new elements are included in the system and it will be necessary to take into account their faults. These elements are sensors and power electronic devices that since a control point of view are the system sensors and actuators. Fault tolerance tries to maintain the system under control in case a fault appears in the system. If this is not possible, it takes the system to a safe operational point. In this paper a fault-tolerant control for induction motors is designed. Based on a direct torque control, new control strategies have been added in case current sensor and power switch faults are detected. The challenge is to overcome these faults without any physical redundancy of sensors or power switches as other authors propose. With the proposed control, it will be possible to guarantee the motor operation in the whole speed-torque range with one or none current sensors instead of the two usually used, though the performance will be slightly worsened. In case of inverter faults, the operation range will be restricted but the performance with respect to the fault situation is improved.     

安全访问控制系统的设计和实现

访问控制是现代企业信息系统设计的核心,它控制用户行为,保护系统资源的安全。传统的访问控制模块的设计与应用系统紧密耦合,使其无法得到很好的复用。本文介绍了轻量级目录访问控制协议(LightweightDirectoryAccessProtocol,简称LDAP)和基于角色的访问控制基于角色的访问控制(Role-basedAccessControl,简称RBAC)模型,基于它们设计了一个高效、安全的访问控制系统。该系统在省邮政综合服务平台中的到应用,有效解决了原有系统设计中的一些弊端。     

非线性系统的直接自适应输出反馈监督模糊控制

针对一类单输入单输出非线性不确定系统，提出一种稳定的直接自适应模糊输出反馈监督控制算法，该算法不需要系统的状态完全可测的假设条件，监督控制不仅迫使系统的状态在指定的集合内，而且当模糊自适应控制处于良好的工作状态时，监督控制可以关闭，证明了整个模糊自适应输出反馈控制算法可以保证闭环系统稳定。     

Formation shape control based on bearing rigidity

Distance measurements are not the only geometric quantities that can be used for multi-agent formation shape control. Bearing measurements can be used in conjunction with distances. This article employs bearing rigidity for mobile formations, which was developed for robot and sensor network localisation, so that bearings can be used for shape control in mobile formations. The first part of this article examines graph theoretical models for formation network analysis and control law design that are needed to maintain the shape of a formation in two-dimensional space, while the formation moves as a cohesive whole. Bearing-based shape control for a formation of mobile agents involves the design of distributed control laws that ensure the formation moves, so that bearing constraints maintain some desired values. The second part of this article focuses on the design of a distributed control scheme for nonholonomic agents to solve the bearing-based formation shape control problem. In particular, a control law using feedback linearisation is proposed based on shape variables. We simulate the shape control behaviour on differential drive agents for an exemplary bearing rigid formation using the results obtained in the first and second parts of this article.     

Online Adaptive Approximate Optimal Tracking Control with Simplified Dual Approximation Structure for Continuous-time Unknown Nonlinear Systems

This paper proposes an online adaptive approximate solution for the infinite-horizon optimal tracking control problem of continuous-time nonlinear systems with unknown dynamics. The requirement of the complete knowledge of system dynamics is avoided by employing an adaptive identifier in conjunction with a novel adaptive law, such that the estimated identifier weights converge to a small neighborhood of their ideal values. An adaptive steady-state controller is developed to maintain the desired tracking performance at the steady-state, and an adaptive optimal controller is designed to stabilize the tracking error dynamics in an optimal manner. For this purpose, a critic neural network (NN) is utilized to approximate the optimal value function of the Hamilton-Jacobi-Bellman (HJB) equation, which is used in the construction of the optimal controller. The learning of two NNs, i.e., the identifier NN and the critic NN, is continuous and simultaneous by means of a novel adaptive law design methodology based on the parameter estimation error. Stability of the whole system consisting of the identifier NN, the critic NN and the optimal tracking control is guaranteed using Lyapunov theory; convergence to a near-optimal control law is proved. Simulation results exemplify the effectiveness of the proposed method.      

Suction Control of a Robotic Gripper: A Neuro-Fuzzy Approach

This paper discusses a fuzzy logic control system designed to determine, regulate and maintain the amount of suction needed by a robotic gripper system to perform reliable limp material manipulation. A neuro-fuzzy approach is followed to determine the amount of desired suction (depending on experimentally derived data and plant characteristics). A knowledge-based valve controller is then designed to generate, regulate and maintain the amount of suction calculated by the neuro-fuzzy suction module. The performance of the overall suction control system is compared with actual experimental results obtained when using a prototype gripper system to handle limp material. Further, performance of the fuzzy logic based valve controller is compared to conventional PD and PID controllers. The proposed control scheme is found to enhance the overall functionality of the prototype robotic gripper system.     

北斗导航时间同步系统在智能电网建设中的应用

鉴于传统单向授时时钟系统难以避免的时间固有误差和累计误差,无法满足智能电网对全网时间同步更高精度的要求,结合山西电网实际情况,提出基于北斗卫星导航系统的电网时间同步系统建设方案,并在智能变电站建设中得到具体应用,各项功能满足设计要求,可实现对全省发电、输电、配电网络的时间同步系统组网和集中监测维护,为电力系统提供安全、可靠的统一时间基准。