pH控制在管状流动反应器中的应用(英文)

Tubular flow reactors are mainly used in chemical industry and waste water discharged units. Control of output variables is very difficult because of the existence of high dead-time in these types of reactors. In the present work, sodium hydroxide and acetic acid solutions were sent to the tubular flow reactor. The aim was to control pH at 7 in the nonlinear region. The pH control of a tubular flow reactor with high time delay and a highly nonlinear behavior in pH neutralization reaction was investigated experimentally in the face of the various load and set point changes. Firstly, efficiency of conventional Proportional-Integral-Derivative (PID) algorithm in the experiments was tested. Then self-tuning PID (STPID) control system was applied by using the ARMAX model. The model parameters were calculated from input–output data by using PRBS signal as disturbance and Bierman algorithm. Lastly, the experimental fuzzy control of pH based on fuzzy model was achieved to compare the success of fuzzy approach with the performance of other control cases studied.     

OPTIMAL TEMPERATURE CONTROL IN A BATCH POLYMERIZATION REACTOR USING NONLINEAR GENERALIZED PREDICTIVE CONTROL

The application of Non-Linear Generalized Predictive Control (NLGPC) to the free radical solution polymerization of styrene in a jacketed batch reactor has been realized. The dynamic behavior of polymerization reactor is modelled and simulated for control purposes. The optimal temperature policies for minimum time, desired conversion and molecular chain length were obtained at different initiator concentrations by applying the optimal control theory which is based on the Hamiltonian principle. The polynomial Nonlinear auto Regressive Integrated Moving Average with external input (NARIMAX) model is used to relate the reactor temperature with heat input for nonlinear control algorithm. The linear (ARIMAX) and nonlinear (NARIMAX) models are utilized in the GPC algorithm for comparison. A Pseudo Random Binary Sequence (PRBS) signal was employed to operate the system. The model parameters are evaluated by using Levenberg Marquart Method. The NLGPC, Linear Generalized Predictive Control (LGPC) and standard PID controllers are applied experimentally to the polymerization reactor by using on-line computer control system. The performance of NLGPC control system was compared with LGPC and standard PID controller. It is concluded that the NLGPC control gives much better performance than the other.     

ADAPTIVE FUZZY MODEL BASED PREDICTIVE CONTROL OF AN EXOTHERMIC BATCH CHEMICAL REACTOR*

An adaptive fuzzy model based predictive control (AFMBPC) approach is presented to track the desired temperature trajectories in an exothermic batch chemical reactor. The AFMBPC incorporates an adaptive fuzzy modeling framework into a model based predictive control scheme to derive analytical controller output. This approach has the flexibility to cope with different fuzzy model structures whose choice also lead to improve the controller performance. In this approach, adaptation of fuzzy models using dynamic process information is carried out to build a predictive controller, thus eliminating the determination of a predefined fixed fuzzy model based on various sets of known input-output relations. The performance of the AFMBPC is evaluated by comparing to a fixed fuzzy model based predictive controller (FFMBPC) and a conventional PID controller. The results show the better suitability of AFMBPC for the control of highly nonlinear and time varying batch chemical reactors.     

模型预测控制在钠氨合成工艺上的应用研究

基于钠氨合成连续化生产工艺,从化学反应机理出发,建立钠氨塔式反应器动态机理模型。并对模型进行动态分析,对多变量非线性模型进行集总化、线性化处理。推广单变量模型预测控制到多变量模型预测控制,对反应器温度进行控制。通过仿真比较,验证了MPC控制算法比PID控制具有更好的控制效果。     

APPLICATION OF ADAPTIVE PID CONTROL WITH GENETIC ALGORITHM TO A POLYMERIZATION REACTOR

This article describes the application of adaptive PID control with genetic algorithm (GA) to a jacketed batch polymerization reactor. This method was used to keep the polymerization reactor temperature at the desired optimal path, which was determined by the Hamiltonian maximum principle method. The reactor was simulated and the model equations of this jacketed polymerization reactor were solved by means of Runge-Kutta-Felthberg methods. A genetic algorithm can be a good solution for finding the optimum PID parameters because unlike other techniques it does not impose many limitations and it is simple. In this research, suitability of these parameters was checked by the integral absolute error (IAE) criterion. The control parameters in the PID algorithm were changed with time during the control of a polymerization reactor. It was seen that the genetic algorithm was able to tune the PID controller used in this system in terms of higher robustness and reliability by changing the parameters continuously.     

基于mamdani规则的焦炉高压氨水模糊/PID复合控制算法研究

针对焦炉高压氨水对象的非线性和复杂性,提出了一种高压氨水模糊/PID复合控制算法。它将模糊推理系统和传统PID算法融合起来,较好地解决了由于不确定因素影响和焦炉工业对象的复杂性而难以建立精确数学模型的问题;当高压氨水压力与期望压力值误差较大时,模糊推理系统工作,自动识别焦炉系统是否加煤,加快控制过程;当高压氨水压力与期望压力值误差较小时,PID控制器工作,精确地获得稳定的氨水压力。通过对模糊推理系统的仿真结果证明,该控制算法是可行的和有效的。     

基于智能算法的啤酒发酵温度过程控制

针对啤酒发酵温度控制过程的大惯性、大时滞及非线性等特点,将传统模糊PID控制算法进行优化并改进,提出了模糊PID智能控制算法,当偏差较大时采用响应速率快的模糊控制,偏差较小时采用多层神经网络PID控制算法。MATLAB仿真结果证实该控制算法提高了啤酒发酵温度控制过程的静态误差和动态响应速度,并且具有适应环境变化的学习能力。     

模糊PID控制器的发展

将模糊控制技术和PID控制相结合，可克服常规PID控制器的不足，使PID控制器具有参数自适应能力。介绍了模糊控制器和PID控制器间的关系，从一维、二维及三维模糊控制器的输入－输出形式上，以及解析分析角度出发，可以说模糊控制器人本质上讲是一种非线性PID控制器。还总结了模糊PID控制器的结构。模糊PID控制器可分成两大类，一类由参数可变的PID控制器及一个模糊控制器共同构成，模糊控制器用于完成PID参数的在线整定，控制信号仍由PID控制器生成；另一类直接用模糊控制器来构造、实现PID控制功能。分别归纳了这两类控制器的多种结构形式。最后还对模糊PID控制器的发展进行了展望，提出了模糊PID 控制器结构的选择、控制器参数调整及控制器评价标准的确定这几方面是今后工作的重点。     

模糊非线性内模控制算法及其在pH值控制中的应用

pH值控制过程具有较强的非线性,历来是过程控制研究的一大热点,本文针对pH值控制系统提出了一种基于模糊推理网的非线性内模控制算法（FNIMC）。模糊推理网用于辨识对象的模糊模型;FNIMC由一个逆模控制器和具有一个可调参数的鲁棒滤波器组成。仿真结果表明该算法优于非线性PID调节器,且计算效率高。     

基于模糊控制的螺杆挤出机温度控制系统设计

以螺杆挤出机温控系统的扰动多、非线性、时变以及大滞后的特性,研究得到了智能化的控制算法,对于现场无法充分预料的情况,这种温度控制系统能够发挥重要的作用。使用Zig Bee无线传感技术可实现温度监控的远程操作,提升检测效率和水平。对远程无线温度控制系统的硬件系统进行了设计,对CC2430射频主控芯片的外围电路、温度传感电路以及温度控制电路进行设计。针对螺杆挤出机温度控制系统进行实例分析,研究结果表明:使用常规PID控制器,在阶跃信号和脉冲干扰信号作用下,系统超调量和稳定时间不能够满足螺杆挤出机温度控制的要求。使用模糊PID控制器,相比常规PID控制器的超调量和稳定时间要明显增强。以尼龙6/Ca Cl2复合材料挤出为例,分别使用常规PID控制算法和模糊控制算法进行对比分析,研究温度控制精度对产品成型质量的影响。在模糊控制算法下,三种产品(温度设置分别为240,260,280℃)的缺口冲击强度合格率比较使用常规PID控制算法时提高了6.87%,弯曲应力合格率、断裂伸长率合格率、拉伸强度合格率分别提高了8.67%,9.33%,8.77%。     

模糊自调整PID控制在电厂锅炉水处理中的应用

针对锅炉水处理系统所具有的非线性、时变、大延迟的特点,对其工艺和控制过程进行了详细的研究。突破了常规的PID及模糊单独控制的方法,采用了两者相结合的控制策略,使其扬长避短,即在常规的PID调节器的基础上,根据误差及误差的变化,通过模糊推理来实现PID参数的自调整。与现有控制算法相比,该算法简单、实时性强、调节效果好,从而具有较好的工程应用前景。     

模糊控制在磨矿分级自动控制中的应用研究

针对目前磨机运行过程中随机干扰因素多、过程机理复杂、非线性、大滞后、各环节变量相互耦合作用大等特点,研究一种以模糊控制和PID控制相结合的控制方案。结合工程实际介绍模糊控制的基本原理,通过测量与栽荷紧密相关的磨机电流,采用二维模糊控制器对给矿量设定值进行模糊控制,提出给矿量设定值的控制算法和控制规则。实际应用结果表明,该方法有效地解决了磨机所发生胀肚和欠载的问题,提高了磨机的工作效率和各项工作指标。     

模糊PID复合控制在三聚甲醛生产中的应用

三聚甲醛的合成受很多因素的影响与制约,具有大滞后、强耦合、难以建立合适数学模型的特点。传统的PID控制很难达到工艺指标要求。采用模糊PID复合控制方式,通过模糊控制与PID控制的自动切换,偏差较大时采用模糊控制方式,以减小超调量并缩短调节时间;偏差较小时切换至PID控制以消除稳态误差。模糊PID控制将模糊控制动态性能好与PID控制稳态精度高的优点相结合,在生产过程中取得了明显的效果。     

模糊自适应PID控制算法在纸机烘缸蒸汽系统中的应用

介绍一种模糊自适应PID控制算法及其实现方法.它包含四个部分:①模糊自适应PID参数模型的整定;②模糊逻辑推理及PID参数修正方法;③模糊自适应PID控制算法的实现方法;④系统稳定性分析.该算法能够实现造纸机干燥部烘缸蒸汽温度按设定曲线控制.应用结果表明该算法合理,实现简单,烘缸干燥效果更佳.     

IDENTIFICATION AND NON LINEAR POLE PLACEMENT SELF TUNING PID CONTROL OF A JACKETED WELL MIXED REACTOR

This paper describes the application of Non Linear Self Tuning PID (NLSTPID) system with the intention of controlling the temperature of a cooling jacketed polymer reactor containing toluene and styrene mixture. The use of polynomial Nonlinear AutoRegressive Moving Average with eXternal input (NARMAX) model related with tank temperature and heat input for nonlinear control was emphasised. The first part of the paper presents an identification algorithm for the construction of polynomial NARMAX and AutoRegressive Moving Average with external input (ARMAX) models. A Pseudo Random Binary Sequence (P.R.B.S) signal was utilised as a forcing function in order to determine the parameters of the models. Levenberg Marquardt algorithm was used to estimate the relevant parameters of NARMAX model. Similar work was carried out for ARMAX model using Bierman, Kalman and Least Square Estimation algorithms. The time response of the tank temperature obtained from computer simulation, identified models and experimental data to a unit step change in manipulated variable were compared. Next, linear and non linear models were used with STPID algorithm to demonstrate the performance of the available control in response to disturbances. All theoretical works were compared with experimental data.     

基于神经网络和多模型的非线性自适应PID控制及应用

针对一类未知的单输入单输出离散非线性系统,提出了基于神经网络和多模型的非线性自适应PID控制方法。该方法由线性自适应PID控制器、神经网络非线性自适应PID控制器以及切换机构组成。采用线性自适应PID控制器可保证闭环系统所有信号有界;采用神经网络非线性自适应PID控制器可改善系统性能;通过引入合理的切换机制,能够在保证闭环系统稳定的同时,提高系统性能。理论分析表明,该方法能够保证闭环系统所有信号有界,如果适当地选择神经网络的结构和参数,系统的跟踪误差将收敛于任意给定的紧集。将所提出的方法应用于连续搅拌反应釜,仿真结果验证了所提出方法的有效性。由于该方法基于增量式数字PID控制器,在工业过程中有着广阔的应用前景。     

带夹套的反应釜温度控制器及LabVIEW实现

提出了一种带夹套的反应釜温度控制系统及控制方法:通过测温装置测得的反应釜和夹套内的实时温度,采用串级PID控制方法控制夹套内的温度,从而控制反应釜内的温度.     

模糊PID控制系统设计及MATLAB仿真

在工业生产中,PID控制不适合时变系统,其参数调整也更为复杂。模糊PID控制利用专家经验得出的模糊规则,通过模糊控制器近似推理实时修正PID参数,使控制效果良好。选取双关节机械手为研究对象,利用模糊控制规则确定隶属度函数和推理方法,在Simulink中搭建模型进行仿真分析。实验结果表明,模糊PID控制在各方面均优于PID控制系统。     

模糊PID控制器在无刷直流电机控制系统中的应用

针对传统PID控制依赖被控对象精确的数学模型,应用于无刷直流电机调速难于达到良好的动态响应的缺点,将模糊PID控制器应用于无刷直流电机的控制中,运用模糊控制原理对PID参数进行在线调整。在分析无刷直流电机数学模型和控制方法的基础上,在MATLAB中应用Fuzzy Toolbox和Simulink对无刷直流电机调速系统进行仿真。实验表明,模糊PID控制相对于传统的PID控制具有更好的动态和静态性能,控制精度也大为提高。     

连续反应釜温度控制系统的设计与仿真

针对连续反应釜中进行的化学反应特性,按照过程的动力学方程和能量平衡等关系,设计了一套基于西门子PCS7的连续化学反应釜(CSTR)温度控制系统。由于连续反应釜内温度的非线性、时变等特性,采用变结构模糊控制结合前馈、串级、分程等先进的控制方式,克服了传统PID算法参数调整复杂、超调量大的缺点。仿真结果表明:对温度采用变结构模糊控制能获得较好的稳态精度和动态特性,满足了反应釜内温度控制的要求。