【作者】 马海；

【导师】 何顶新；

【作者基本信息】 华中科技大学 ， 控制理论与控制工程， 2007， 硕士

【摘要】 在对地表水或者污水的化学生物成分进行测量时,需要在一定化学试剂的作用下,将被测溶液在某一固定温度和一定的压力下进行一定时间的加热预处理,然后才能获得准确的测量结果。因而加热的快速性、稳定性以及温度控制的精度都直接影响着测试结果的准确性。针对这种应用背景,本文对专用于分析测试试剂作加热消解的电控装置(消解仪)的温度控制系统进行了研究与讨论。本文在介绍消解仪温控系统原理以及基于各种PID控制技术的温控策略的基础上,讨论了经典PID、数字PID、史密斯与大林控制算法以及专家智能PID控制技术等在温度控制中的应用。提供了一种构建消解仪温控系统的方法,并分析了构建消解仪的硬件和软件的设计方案。在消解仪的系统硬件部分,文中主要介绍了以PWM控制和固态继电器为核心的控制电路,包括输入/输出电路、电流/电压转换电路、存储器的扩展、液晶显示电路、温度检测电路和用RC、运算放大器组成的硬件PID控制电路等。在系统软件部分包括用C语言编写的单片机数据采集、数据分析处理、时钟模拟控制以及液晶显示等软件程序组成。通过各种PID控制技术的温控实验,得到了相关实验数据。控制效果的比较表明,专家系统PID控制方案在线修正PID参数的效果最好,比起常规的控制策略,控制的超调量降低了95%,调节时间缩短了50%,精度在0.5℃以下。该方法为非线性、大滞后和参数时变的控制找到了一条切实可行的解决途径,提高了温度控制的精度和快速性、稳定性,达到了所期望的消解仪的性能要求。更多还原

【Abstract】 When the biological and chemical composition of surface water or sewage measured, need to be heaten carrying on certain time in a certainly regular temperature,under the process of certain chemical reagent, thus the accurate metrical result could be obtained. Accuracy and stability of the pyrogenation and the precision of temperature control influences the test result directly.Applications for this background, this thesis is about discussion and research of special-purpose on heating tested reagent equipment (Digester)’s temperature control system.This Thesis is on the introduction about digester’s temperature-controled systematic principle and many kinds of temperature-controled tactics basis on the PID technology. It has discussed Classical PID, Digital PID, Dahlin and Smith control algorithms and expert intellectual PID system’s application in the temperature control, and has offered a kind method of constructing the temperature-controled systematic, and analyses the hardware of this system and software of design plan in detail.Digester’s systematic hardware is the circuit of taking PWM and solid state relay as the core, including input / output circuit, current / voltage changed circuit, circuit of the expansive memory, liquid crystal circuit, circuit of the temperature measure and hardware PID control circuit made up of RC, amplifier etc..The temperature-controled systems software is written by C language including data gathered, data analysed and processed, clock simulation and software procedures of the liquid crystal display.The experiments of different PID control strategy has been done, relevant experimental data has got. Through comparing the real effect of every algorithm, find out that useing expert system PID - It is best to utilize the knowledge base of expert system to output result that revises PID parameter online, compared with the routine control strategy, exceed adjusting amount to reduce by 95%, regulate time to shorten by 50%, precision is under 0.5 degrees Centigrade. It find a feasible settlement way by this Method for being non-linear heavy lagging behind and control that at the parameter, improve precision, speediness and stability of temperature control, it reachs the desirable performance of digester.更多还原