多线程技术在自动报警系统中的应用

在自动报警系统中,采用了多线程技术以解决前台监控和后台通讯的协同工作问题．通过对开发工具 Ｄｅｌｐｈｉ ３ ．０ 中提供的多线程对象 Ｔ Ｔｈｒｅａｄ 类,以及临界区、互斥量等同步控制对象类的介绍,阐述了如何编写出简捷、有效的多线程应用程序和安全调用这些程序的方法,并指出在多线程程序开发过程中应注意的事项     

以太网分布式数据采集同步和实时传输研究

研究虚拟仪器通过以太网控制分布式数据采集嵌入式系统进行同步数据采集和实时数据传输。通过分析各采集单元的采集同步误差源，提出减小同步误差的方法；分析通用嵌入式数据采集系统同时实现数据采集和实时传输的难点，提出解决方案。在各采集系统中运用以太网、TCP／IP网络通信协议。通过对标准网络协议进行改进、简化，减小网络延时。提高系统网络速度和实时性。对系统的网络速度、可靠性、同步误差以及实时性的实验测试。验证了系统方案的可行性和对标准网络协议改进、简化的有效性。     

气液联合多通道同步加载比例复合控制系统

研究了多输入多输出气液联合同步加载系统的数学模型及其特点,通过分析气压加载的动态过程,指出气压加载子系统的纯滞后与大惯性是限制整个系统动态性能提高的关键环节,并提出了加快系统动态响应速度的方法。针对气压加载与液压加载特性显著不同的特点,提出一种比例复合控制方法。该方法通过基于H∞理论的鲁棒控制器、同步控制器及协调控制器的复合控制作用,分别控制各通道的电液或电气比例阀,实现6个液压加载通道与4个气压加载通道的同步协调加载。试验结果验证了该方法的有效性与实用性。     

周期性机械振动主动控制算法

为提高周期性机械装置的隔振性能,减少其对底座(或地面)及周围环境的影响,采用由弹性橡胶和压电堆作动器组成的主动悬置(active control mount, ACM).针对压电堆作动器输出位移较小的情况,设计液压位移放大机构.通过对压电作动器和橡胶主簧性能的分析,建立由主动悬置构成的隔振系统的力学模型.周期性机械振动系统,其周期振动信号可用作控制同步信号,因此控制系统采用基于同步滤波-X LMS(least mean square)算法的自适应控制策略,传递到机座的残余力作为误差信号,实现对周期性机械振动系统的主动控制.计算机仿真实验结果表明,采用这种主动悬置和同步滤波-X LMS算法的主动控制系统,相对于采用普通橡胶悬置的被动系统,明显减少了对底座的力传递,减振效果明显.     

Arc fault location: A nonlinear time varying fault model and frequency domain parameter estimation approach

In this paper a frequency domain formulation for nonlinear arcing fault location is presented. The proposed fault location formulation uses as input data first cycles after the fault inception voltages and currents. The formulation is based on circuit analysis and a parameter estimation method. To consider the main characteristics of nonlinear arcing faults, a time varying resistance embedded in a nonlinear model is proposed and used. The formulation is developed for the case of the most frequent single line-to-ground faults using phase components. The effects of fault inception angle, time-varying series resistance, source impedance, load flow, sampling frequency and others factors are investigated and analyzed. This new approach was successfully tested through computer simulation and real data obtained from a Southern Brazilian Energy Utility. The proposed method was developed as dedicated software and is currently used by CEEE-GT.     

一种用于系统互连的实时自主同步串行总线

针对当前小型化和高密度化的设计需求，提出了一种用于系统互连的实时自主同步串行总线，其能有效替代当前使用大量通用输入输出进行控制及指示信号传输的传统做法，实现更高效的系统板内及板间互连。     

A start strategy for synchronized connection of MMCs to an AC system

Two series problems plague prevailing modular multilevel converter (MMC) start strategies: (1) during uncontrolled charging, the capacitor voltage of an MMC disconnected from the AC source is half of the capacitor voltage of an MMC connected to the AC source, and (2) the MMC system cannot synchronously connect to the AC grid. To solve these problems, a smooth-start scheme for synchronized connection of MMCs to an AC system is proposed. The proposed smooth-start process is divided into three stages: a voltage-imposed stage, a connection stage, and a regulation stage. During the voltage-imposed stage, MMCs disconnected from the AC source are charged with the proposed M-δ controller. In the connection stage, the M-δ controller facilitates synchronized connection to the AC network to diminish the impulse current, and a buffer function is used to smoothly switch the M-δ controller to a decoupled d-q controller. During the regulation stage, the reference values of the d-q controller are adjusted to rating values. Simulation results indicate that the proposed start strategy is feasible and effective.     

多电机同步传动控制系统分析

针对产品制造过程中多单元同步传动控制问题，在分析机械总轴同步控制和主令参考同步控制方案优缺点的基础上，提出了多电机同步传动调速系统的虚拟总轴控制方案。该方案虚拟总轴控制模糊机械总轴的机械性，既保留了机械总轴控制方式固有的同步特性，又具有主令参数同步控制方式中各单元间完全没有耦合，任一单元的扰动不会影响其它单元运动状态的优点，虚拟总轴系统的由虚拟总轴、虚拟内内轴以及机械单元等部分组成，虚拟机械部分采用软件实现，由于输入信号经过总轴作用并过滤，易于单元驱动器跟踪。Matlab仿真结果表明，该方案易于调节参数，动态性能好，系统容量大。     

A new robotic assembly modeling and trajectory planning method using synchronized Petri nets

In this paper, a new approach to trajectory planning, performance Evaluation, and control for robotic assembly is presented. The assembly process is modeled as a discrete event system using synchronized Petri nets (SynPN). In a SynPN model, transitions are associated with firing conditions depending on external events. Due to this characteristic, SynPN is commonly used to model the connection between system states and external signals. The most important force/moment and position/orientation information in the assembly process serve as external events. Using the external events, the assembly states can be recognized and the system will be directed to the desired end state. Furthermore, trajectory planning algorithms and performance evaluation criteria of a discrete event system are also studied based on SynPN model. Finally, simulation and simple experiments are discussed in which a successful peg-in-hole assembly is fulfilled.