智能家庭网络的规范与标准综述

信息产业部正在制定国家标准家庭网络平台技术规范,文中综述了现有几种有代表性的家庭网络协议,指出了它们在应用方面的优劣势,并给出了展望.     

从智能外设到媒体服务器

分别讨论了智能外设和基于软交换的媒体服务器的功能和作用。时两者的异同点进行了比较。指出从智能外设到媒体服务器的演进路线和进一步发展的方向。     

低载噪比下P码接收精频测量新算法及性能分析

GPS信号的P码码速率是C/A码的10倍,所以捕获时搜索相同时长的码相位需要做10倍点数的相关运算,相关运算通常用频域FFT实现,而硬件平台对FFT点数的限制使捕获得到的多普勒频率估计误差很大,因此C/A码的各种精频测量方法不能适用于低载噪比下的P码接收.本文针对P码的特性,在利用DFT相位差估计信号频率的基础上,提出了一种低载噪比下P码接收精频测量的新算法--差分相干法,并从理论和蒙特卡罗仿真两方面分析、比较了该算法与传统算法的性能,证明了本文算法能够兼顾接收机系统的实时性和精频测量精度的要求.     

ACS800变频器DTC在轧机电动压下系统中的应用

本文简要介绍了ACS800变频器直接转矩控制（DTC）的原理,并结合热轧可逆轧机电动压下系统的特点.对变频器参数进行配置,以及利用Drive Window软件对实际信号进行监控和调试。     

A Differential-Mode Wideband Bandpass Filter on Microstrip Line for UWB Application

A differential-mode wideband bandpass filter (BPF) on microstrip line is proposed with good common-mode suppression. A four port two stage branch-line differential-mode BPF is first designed. Then, open circuited stubs are attached to the middle of two of the vertical branches. As such, its two-port bisection becomes a bandpass or bandstop filtering topology under differental- or common-mode excitations, respectively. The lengths and widths of these stubs can be properly adjusted to produce a highly attenuated and widened stopband under the common-mode operation. Finally, a wideband differential-mode BPF is designed and fabricated. The predicted and measured performances are in good agreement with each other, showing good common-mode suppression with an insertion loss higher than 20 dB over the differential-mode passband with a fractional bandwidth of 65%.     

基于CAN_GSM车辆监控系统设计

针对传统车辆监控系统的不足,提出了一种基于CAN／GSM的部队车辆监控系统。该系统采用CAN总线技术,依托GSM网络,将采集到的车辆信息实时传送到监控中心,并且采用动态参数设置,能够对车辆全面,实时地进行监控,具有很好的灵活性和扩展性。     

基于两相静止坐标系三相电压型PWM整流器控制策略的研究

本文研究了基于两相静止坐标系中的三相电压源型PWM整流器的控制方案,引入广义积分器实现三相电流在两相静止坐标系下跟踪控制。仿真结果证明了文中所提出的控制策略的有效性和可行性。     

An inchworm mobile robot using electromagnetic linear actuator

The capability of motion is one of the important aspects for a micro-robot to fulfill its given tasks. Micro-autonomous systems usually require large force, large displacement and less power consumption. Among different actuation schemes, electromagnetic actuator shows the benefit in a combination of force, displacement and cost effective control. A bristle-based inchworm mobile robot using a short stroke electromagnetic linear actuator is described in the paper. The main body and movable unit of the robot are joined by using a sealed bellows and the bristle legs are designed so that it can operate both on plane surfaces and in liquid. The actuator designed for the robot is a tubular type linear machine with an overall size of Φ7 × 10 mm. The key dimensions of the actuator were determined through magnetic field analysis to achieve optimum force output and necessary travel stroke within the limited space. The predicted actuation force of the actuator is 20 mN and the stroke length is 1.2 mm. Two working prototypes of the actuator were constructed and the performance tests show the effectiveness of the design. A sensorless control scheme with a novel start-up strategy for the designed actuator was developed based on the robotic system modeling and the analyzed results show the satisfactory performance of the system.