基于动态二进制搜索算法的改进防碰撞算法

该文在动态二进制搜索算法的基础上提出了一种新的防碰撞算法,该算法充分利用已得到的冲突信息,有效减小判断过程中数据的传输量。通过对新算法的分析,可知本算法相对于动态二进制搜索算法有明显的优势。     

支持新型控制协议SIP的电力系统视频监控设计

针对电力系统视频监控工程的实际技术问题,采用嵌入式设备和基于网络分层的SIP管理架构,提出了一种支持新型控制协议SIP的电力系统视频监控设计,包括SIP的控制机制、基于SIP的监控系统结构、视频监控系统总体组成、硬件设计、软件设计和实验结论等;该系统的各成员之间可以通过组播或单播的方式进行交互,并在域内处理大量的信令信息和媒体流信息,具有扩展性、智能性、灵活性、自主性和互操作性等多种优良特性;经测试指标符合技术规范,实现了电力系统视频监控管理及控制的基本和扩展功能。     

Effect of aspect ratio on convection in a porous enclosure with partially active thermal walls

The aim of the present numerical investigation is to understand the effect of aspect ratio and partially thermally active zones on convective flow and heat transfer in a rectangular porous enclosure. Five different heating and cooling zones are considered along the vertical walls while the remaining portions of the sidewalls and top and bottom of the enclosure are adiabatic. The Brinkman-Forchheimer extended Darcy model is used in the study. The governing equations are solved by the finite volume method with the SIMPLE algorithm. The computations are carried out for a wide range of parameters and the results are presented graphically. The results reveal that the location of heating and cooling zones has a significant influence on the flow pattern and the corresponding heat transfer in the enclosure. The rate of heat transfer approaches to a constant value for very low values of the Darcy number. The heat transfer rate is decreased on increasing the aspect ratio.     

一种用于微喷的感应加热器设计与仿真

提出了一种用于热微喷头的感应加热器新结构。进行了相关的结构和工艺设计,在MEMS工艺环境下制作出了可以非接触加热,工艺结构简单,使用寿命长的微感应加热器。使用ANSYS对微感应加热器进行了建模和仿真分析,结果显示:感应加热器的最大加热功率可达到5 mW以上,满足设计要求,同时得到了感应加热器的功率影响因素。     

Accurate robotic belt grinding of workpieces with complex geometries using relative calibration techniques

Robotic belt grinding operations are performed by mounting a workpiece to the end effector and commanding it to move along a trajectory while maintaining contact with the belt grinding wheel. A constant contact force throughout the grinding process is necessary to provide a smooth finish on the workpiece, but it is difficult to maintain this force due to a multitude of installation, manipulation, and calibration errors. The following describes a novel methodology for robotic belt grinding, which primarily focuses on system calibration and force control to improve grinding performance. The overall theory is described and experimental results of turbine blade grinding for each step of the methodology are shown.     

基于旋转谐振结构的单芯片二维电场传感器

提出并研制了一种二维电场检测传感芯片,将四个电场测量微型单元和旋转式驱动微结构集成在3. 5 mm ×3. 5 mm的敏感结构上,实现了单芯片的电场二维测量.介绍了传感器的工作原理、敏感结构的设计,以及基于绝缘体上硅( SOI)工艺的单芯片微型二维电场传感器制备工艺技术.成功研制出传感器原理样机,研究了微型二维电场传感器的标定方法,开发了用于电场二维标定的测试装置,并在室温常压下对传感器进行了二维标定.实验结果表明:该传感器能够有效减小电场的轴间耦合干扰,测量误差优于7. 04%,线性度可达到1. 25%.     

闪电快电场信号时频特性的小波分析

应用小波变换方法将具有短时非平稳特点的闪电快电场时域波形信号转换到二维的时频平面,从时间和频率上同时描述闪电快电场信号的电场强度或相对能量分布,揭示其所包含的不同频率分量及其随时间变化的特性.分析结果表明,基于小波变换的闪电快电场信号时频特性分析可以挖掘闪电电场更深层次的变化规律和特征;也为闪电放电类型的识别研究提供了新的思路.     

Decentralized voltage control of distributed generation using a distribution system structural MIMO model

The voltage control problem in Low Voltage (LV) distribution systems is becoming increasingly important due to the presence of Distributed Generation (DG). Recently, DG units have been proposed to contribute to voltage control according to a Volt/Var law which does not realize regulation. Moreover, since the existing LV systems are operated in a decentralized way without communication links, the simultaneous response of the controllers of the DG units may result into operational conflicts and instability. To overcome these problems, the present paper illustrates a design methodology for decentralized voltage controllers that act on DG reactive power injections. The controllers are suitable for the LV systems since they ensure voltage regulation and stability by using only local measurements and without information exchanges. The design is based on a proposed structural MIMO model of the distribution system. Robust stability is also analyzed: changes in the operating conditions of the distribution system are modeled as unstructured additive uncertainties affecting the MIMO model. A case study gives evidence of the applicability of the proposed design; the performance of the controllers in terms of both stability and regulation of the nodal voltages of three DG units connected to a LV distribution feeder is tested by numerical simulations; finally, a comparison with a Volt/Var technique is performed.     

基于人体姿态检测的体感滑板控制系统设计

为改善电动滑板的易操纵性,设计了基于人体姿态检测的体感滑板控制系统.该系统由人体姿态检测与滑板主控两大部分组成.首先,通过实验,分析了人体以不同姿态驾驶滑板时MPU6050传感器采集到的加速度和角度的数据变化规律.在此基础上,确定了驾驶滑板时,识别人体姿态改变的方法.最后,制作了人体姿态检测与滑板控制电路,并编写了相应的控制程序.调试结果表明,该系统响应准确,达到了设计要求.     

基于能量反馈协调控制的电动汽车底盘减振方法

针对电动汽车底盘振动控制及其能量反馈的设计要求,建立其1/4馈能式主动悬架模型,从能量角度使用基于线性二次最优调节器(Linear Quadratic Regulator, LQR)的控制方法,使悬架在控制力作动下达到车身振动能量尽量小并获得一定的振动反馈能量.在理论分析基础上,使用与Simulink建立联合仿真系统,分析LQR控制器协调底盘在复杂工况下的振动控制及其能量反馈的综合效果.分析表明,所用LQR协调控制方法能有效协调减振及其能量反馈.