科创中国

设计基于AD7846和FPGA的数/模转换电路,介绍AD7846的主要特点、基本结构、引脚功能和工作原理,设计基于AD7846转换芯片的数/模转换硬件电路,利用Verilog语言描述AD7846的控制时序,并给出具体的仿真结果.实践结果证明,该设计可行,可取代传统的"CPU+专用的数/模转换(D/A)芯片"设计结构,进一步提高系统的可靠性和抗干扰能力.

分析了Ad Hoc网络及其应用,对比了典型的主动式路由协议DSDV和按需路由协议AODV的寻路机制和路由维护过程.基于VRNET Developer网络仿真平台,在坦克营连战术分队网络背景下,对两种路由协议的性能进行仿真比较.实验结果表明,DSDV适用于节点数量少、速度变化缓慢并且有较高实时性要求的战术分队网络,而AODV适用于节点数量多、移动速度快的战术分队网络.

文中介绍了一种主从模式的蓄电池远程监测系统终端.以Si1015为主控芯片,该终端主要完成了蓄电池组的内阻、电压、环境温度的测量,主从模块之间通过无线方式传输数据,主模块通过GPRS实现终端与监控中心的数据传输.

本文介绍了一种基于HART协议的智能温度变送系统.该系统由AVR单片机、HART芯片SD2015B、A/D转换芯片AD421构成,支持多种传感器信号输入,通过电流环路实现模拟和数字信号的同时传输,能够应用在工业控制、智能仪器仪表等方面,具有较强的实用性.

For the Cooperative Adaptive Cruise Control(CACC)Algorithm,existing research studies mainly focus on how inter-vehicle communication can be used to develop CACC controller,the influence of the communication delays and lags of the actuators to the string stability.However,whether the string stability can be guaranteed when inter-vehicle communication is invalid partially has hardly been considered.This paper presents an improved CACC algorithm based on the sliding mode control theory and analyses the range of CACC controller parameters to maintain string stability.A dynamic model of vehicle spacing deviation in a platoon is then established,and the string stability conditions under improved CACC are analyzed.Unlike the traditional CACC algorithms,the proposed algorithm can ensure the functionality of the CACC system even if inter-vehicle communication is partially invalid.Finally,this paper establishes a platoon of five vehicles to simulate the improved CACC algorithm in MATLAB/Simulink,and the simulation results demonstrate that the improved CACC algorithm can maintain the string stability of a CACC platoon through adjusting the controller parameters and enlarging the spacing to prevent accidents.With guaranteed string stability,the proposed CACC algorithm can prevent oscillation of vehicle spacing and reduce chain collision accidents under real-world circumstances.This research proposes an improved CACC algorithm,which can guarantee the string stability when inter-vehicle communication is invalid.

随着时栅位移传感器的产业化发展,高速测量需求的趋势日益凸显,提出了一种基于TDC-GP2的时栅位移传感器信号处理系统。该系统采用STM32F4和AD9958产生时栅位移传感器所需的高稳定、高精度励磁信号,采用高分辨率TDC-GP2数字时钟转换器来测量传感器动、定测头的感应信号相位时间差,将测量结果送入微处理器中处理,以此到达以时间测量空间的目的。经实验表明:48对极时栅传感器整周(0~360°)的误差达到±2.3″,该方案优化了电路结构,提高了时栅位移传感器的测量精度。

为保证电能质量,需要对电能质量的各项指标进行全面的检测和分析,为改善电能质量提供决策依据.在参考电能质量国家标准的基础上,设计了一种以STM32芯片为核心的三相电能质量在线检测装置,给出了其硬件系统设计和基于小波变换算法的程序设计流程图,实现了对电能质量高精度的测量,比较于其他装置的设计方式更加简便但测量精度更高.在此将STM32芯片应用于电能质量检测装置中,降低了成本减小了功耗且测量精度提高.实验结果证明了该设计具有很好的的实用价值.