Active disturbance rejection based trajectory linearization control for hypersonic reentry vehicle with bounded uncertainties

This paper investigates a novel compound control scheme combined with the advantages of trajectory linearization control (TLC) and alternative active disturbance rejection control (ADRC) for hypersonic reentry vehicle (HRV) attitude tracking system with bounded uncertainties. Firstly, in order to overcome actuator saturation problem, nonlinear tracking differentiator (TD) is applied in the attitude loop to achieve fewer control consumption. Then, linear extended state observers (LESO) are constructed to estimate the uncertainties acting on the LTV system in the attitude and angular rate loop. In addition, feedback linearization (FL) based controllers are designed using estimates of uncertainties generated by LESO in each loop, which enable the tracking error for closed-loop system in the presence of large uncertainties to converge to the residual set of the origin asymptotically. Finally, the compound controllers are derived by integrating with the nominal controller for open-loop nonlinear system and FL based controller. Also, comparisons and simulation results are presented to illustrate the effectiveness of the control strategy.     

负温度系数传感器特性检测系统设计

负温度系数(NTC)传感器是一种阻值随温度升高而降低的热敏电阻,广泛应用于家用电器的测控系统中.鉴于不同NTC元件的温度-电阻特性一致性较差,给批量家用电器产品的调试带来不便.因此,NTC特性的自动测量和筛选是十分重要的.文中介绍了一种新型的NTC热敏电阻特性检测系统,阐述了该系统的检测原理和硬件组成,给出了系统的硬件框图和软件流程.该系统实现了NTC传感器温度特性的自动测量和筛选,方便了整机装配前对使用的NTC传感器温度特性的检测,降低了后道工序的调整难度,节省了工时.     

A/D芯片TLC2543与Neuron芯片的接口应用

介绍了lonworks技术中Neuron芯片的一种I／O应用模式和A／D芯片TLC2543的串行接口特性。给出了采用Neuron芯片与A／D芯片TLC2543建构的多通道12位模拟数据采集系统的接口硬件实现方法和相关的软件程序。     

Miniemulsion and conventional emulsion copolymerization of styrene and butadiene: Effect of process on gel content

The properties of styrene/butadiene copolymers obtained by conventional emulsion and miniemulsion polymerizations were studied. Thin layer chromatography with flame ionization detection was used to determine the gel fraction of the copolymer in the latex particles as a function of conversion. It was found that the gel formation began at a higher conversion in the miniemulsion polymerization when compared with that in the conventional process. Also, a lower glass transition temperature was noted at the lowest conversion sampled (～25%), implying a higher initial butadiene monomer concentration within the nucleated miniemulsion monomer droplets when compared with particles formed conventionally. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4616–4622, 2006     

Characterization of sterols in refined borage oil by GC-MS

Borage oil sterols were isolated by TLC and characterized using GC and GC-MS. Several diunsaturated Δ⁵-sterols, some of them not previously recorded in vegetable oils, were found. Of these, 24-methylcholesta-5,23-dienol and 24-ethylcholesta-5,23-dienol could be useful markers for borage oil. Two other diunsaturated Δ⁵-sterols that are rarely found in vegetable oils, 24-methylcholesta-5,24(25)-dienol and 24-ethylcholesta-5,24(25)-dienol, were identified. The diunsaturated C-24(28)-sterol, isofucosterol, was also found, as well as the monounsaturated Δ⁵-sterols campesterol and sitosterol. These are normally present in vegetable oils, which makes them unsuitable as markers for borage oil.     

基于单片机线性F/V转换系统的设计与实现

研究了一种线性F∕V转换系统。利用单片机来检测正弦波的频率,根据检测的频率确定D/A转换的数字量,控制TLC5615串行D/A芯片将频率信号转变为电压信号,使输出电压与频率大小呈线性关系,而且它们的线性关系是不经过原点的直线,而现有的F/V转换的器件都不能满足这种要求。     

一种高速正弦信号发生器的设计

文章提出了基于高速DSP芯片TMS320C5402实现正弦信号发生器的设计原理与方法,介绍了所设计的正弦信号发生器的硬件结构电路图和软件程序结构图。结合DSP硬件特性,通过使用泰勒级数展开法得到设定参数的正弦波波形输出,从而达到设计目的。     

一种工业级数据采集监控系统的设计与实现

论文重点介绍了基于采集芯片TLC2543和USB接口芯片PDIUSBD12的数据采集监控系统的硬件和软件设计.此系统采用主从式结构,上位机软件采用VC++.NET2005编写,对系统实现监控;下位机以AT89S52单片机为核心,通过A/D转换芯片TLC2543进行采集转换,最后将数据传送.上住机与下位机采用PDIUSBD12接口方式进行通信.     

基于TMS320C5402的语音信号压缩存储系统设计

根据TMS320C5402的特点,提出了采用G.711语音编解码算法设计的语音压缩系统,给出了系统的硬件结构和软件流程及A/D、D/A模块与TMS320C5402接口电路的设计方法。该系统具有很高的实时性和实用性。