水泥分解炉温度控制过程的阶跃响应建模与仿真

根据从新型干法水泥分解炉温度控制过程中采集的实测数据,选取从过渡工况到动态稳定工况过程中的典型数据段,用阶跃响应法建立分解炉温度控制过程稳态工作点附近的二阶惯性加纯滞后数学模型;以分解炉出口温度偏差及偏差变化率为输入变量,尾煤变化量为输出变量,使用MATLAB的Fuzzy Logic工具箱设计二维模糊控制器,并在稳态阶...     

玻璃钢管体螺纹磨削机器人控制策略研究

针对玻璃钢管体螺纹磨削机器人作业时对力和位置控制的要求,建立了机器人动力学约束模型,通过对磨削力的建模与分析,采用基于自适应算法的阻抗控制方式。该方法基于机器人和工作对象之间相互作用的分析,实时校正力的参考值,保证机械臂末端的实际作用力能够稳定跟踪期望的磨削作用力。这种方法对因外界环境等未知因素而产生的扰动和误差具有良好的鲁棒性,而且计算量小。基于上述方法,建立机械臂系统的动力学控制器。通过磨削仿真证明该方法具有良好的稳定性,能够满足并符合对机器人实时控制的要求。     

基于小波神经网络的通用模型控制

针对通用模型控制要求被控对象有显式解的局限性,应用小波神经网络来建立非线性被控对象的逆模型.再结合通用模型控制算法,将非线性过程模型直接嵌入到控制器中,来实现对被控对象的逆控制.其参考轨迹是一条典型的二阶曲线,控制器参数具有明显的物理意义,且易于整定.仿真结果验证了该控制策略的有效性.     

一种简单实用的自校正PID调节器

本文介绍一种自校正PID调节器。这种调节器的控制结构是一种改进的不完全微分型PID算法。其设计思想是通过系统辨识,估计被控对象的数学模型,将闭环系统校正为二阶振荡环节。操作人员所要做的工作只是根据工艺要求设定控制系统阶跃响应的上升时间t_r,调节器自动整定控制参数。一.对象模型已知时PID控制器设计设被控过程的传递函数为:     

注射机中不稳定时滞对象的PI-PD控制器设计研究

针对注射机在运行过程中存在不稳定的时滞对象问题,提出一种基于改进的WGC方法实现的PI-PD控制系统。确定一个封闭的稳定区域,计算出凸稳定区域的中心,确定PI-PD控制器参数。该方法精确、计算量小且能保证系统稳定性。仿真案例表明,该方法优于现有的几种方法,能够快速达到稳定状态,可有效地抵抗参数扰动和负载扰动。     

合成氨装置冷凝液处理技术研究与应用

采用活性分子膜超微过滤组合多官能团纤维吸附凝结水处理技术,可有效去除凝结水中游离态、机械分散态、乳化态、溶解态的各种烃类及其衍生物。同时在活性分子膜和复合碳纤维微孔内官能团的作用下,脱除水中的二、三价金属离子,使凝结水达到锅炉给水要求。     

一种煤层气分离过程智能控制器研究与应用

本文在一种广义钟形自调整模糊目标函数控制规则自调整算法控制器设计的基础上,加上一个积分作用,从而得出一种改进的规则自调整模糊控制器,通过对一个典型的二阶系统进行仿真研究,结果表明改进的模糊控制器先进性较强,改进的模糊控制器具有一定的优越性。     

电加热器匀速升降温过程中温度及其变化速率的多模型智能切换控制

在实验室电加热器匀速升降温控制中,由于温度的非线性和时变性,速率控制很难达到理想精度;温度上升或下降至稳态点附近时,在理想工艺曲线下,需同时对温度及其变化速率进行控制,出现了"单控制量-两被控量"的矛盾。针对上述问题,采用偏差累加方法在温度控制器基础上得到温度变化速率控制器,在匀速升温、降温过程中分别利用大幅、小幅对应传递函数构成偏差加权控制器,在控制过程中设计温度热惯性监测量实时监测控制器输出以进行温度及其变化速率的切换控制,在加热器装置上实验的结果表明,该方法提高了速率控制精度,很好地解决了温度及其变化速率控制的矛盾,使响应曲线与理想工艺曲线达到较大程度上的吻合。     

针对不稳定对象的改进动态矩阵控制

针对一般动态矩阵控制算法不能直接用于不稳定对象这一问题,提出一种改进的动态矩阵控制设计方法。该方法先设计由内环控制器构成的反馈环节来稳定对象,再对稳定后的对象进行动态矩阵控制设计。采用现代频域法中的传递函数互质分解法设计内环控制器,并对设计的内环控制器进行抗扰性能和鲁棒性能的H2优化,优化后的内环控制器可独立地调节系统的抗扰性,也能有效地改善系统的鲁棒性。通过Matlab仿真实验与现有方法进行比较,结果表明:本文方法能明显改善系统的鲁棒性和抗扰性。     

基于自适应模糊PID的注塑机温度控制及仿真

为了对注塑机温度精确控制,针对注塑机温度在传统比例积分微分(PID)控制系统中存在的控制偏差大、调节速度慢等诸多不足的现状,提出将模糊控制器和PID控制器相结合,构造成一个自适应模糊PID控制器,运用MATLAB软件建立传统PID和自适应模糊PID控制器模型,对机筒温度进行仿真对比。设定200℃为给定温度,最终仿真结果显示,与传统PID控制器相比,自适应模糊PID控制器实现了注塑机温度的实时控制,达到了超调量小,升温快速及稳态无误差等要求。表明了自适应模糊PID控制器比传统PID控制器对温度的控制效果更加良好。     

基于次最优模型降阶的自整定PID控制器

针对过程工业中含有振荡环节和大滞后环节较难控制的被控对象,设计了一种基于频域辨识的自整定PID控制器.该控制器采用次最优模型降阶算法,辨识出二阶加纯滞后的模型;然后基于给定的相位裕度和幅值裕度,整定出PID参数.并通过仿真实验表明对于不同的被控对象,自整定得到的PID参数均能取得较好的控制效果.     

TUNING PID CONTROLLER FOR OPEN-LOOP UNSTABLE PROCESSES WITH TIME DELAY

A calculation method of PID controller tuning for the first- and the second-order open-loop unstable process models with time delay is presented in this study. Optimum PID controller tuning data based on the models and minimum IAE criterion were obtained via Powell searching technique, and these data were then empirically correlated into several multiple-regression equations by a least-squares method. Thus PID controller tuning based on the models can easily be obtained by the calculation of these correlated equations. Simulation with a reset-feedback PID control algorithm has demonstrated that the proposed tuning method based on the first-order model can provide better results than the latest studies. In addition, simulation has also unveiled that tuning results based on the second-order models are superior to the first-order model for a higher-order process.     

A two-degrees-of-freedom design methodology for interval process systems

This paper presents a two-degrees-of-freedom design methodology for interval process systems to guarantee both the robust stability and performance. For the robust stability issue, the design technique of Chen and Wang (1997) is utilized for searching a robust stabilizing feedback controller. Subsequently, a pre-filter is constructed based on using a frequency domain method to ensure the desired system performance. For illustration, the proposed design methodology is applied to design a robust control system for a second-order unstable plant in the presence of unknown but bounded parameter uncertainties. Simulation results reveal that the proposed scheme is effective and applicable for interval process systems.     

Low-gain internal model control PID controller design based on second-order filter

A design method is proposed for low-gain internal model control (IMC) proportional-integral-derivative (PID) controllers based on the second-order filter. The PID parameters are obtained by approximating the feedback form of the IMC controller with a Maclaurin series, in which the second-order filter is applied using the IMC approach to achieve a low-gain PID controller that is suitable for model mismatch problems. Analytical PID tuning rules based on the second-order filter are derived for several common-use process models. The second-order filter is designed from the desired time domain performances of maximum overshoot and settling time. Furthermore, the robustness of the IMC PID controller based on the second-order filter is analyzed, and results show that its robustness performance is better than the first-order filter under certain conditions. Finally, three categories of models divided by the ration of time constant and time delay are presented in the comparative numerical simulations to validate the effectiveness and generality of the proposed PID controller design method.     

Analytical design of PID controller cascaded with a lead-lag filter for time-delay processes

An analytical method for the design of a proportional-integral-derivative (PID) controller cascaded with a second-order lead-lag filter is proposed for various types of time-delay process. The proposed design method is based on the IMC-PID method to obtain a desired, closed-loop response. The process dead time is approximated by using the appropriate Pade expansion to convert the ideal feedback controller to the proposed PID·filter structure with little loss of accuracy. The resulting PID·filter controller efficiently compensates for the dominant process poles and zeros and significantly improves the closed-loop performance. The simulation results demonstrate the superior performance of the proposed PID·filter controller over the conventional PID controllers. A guideline for the closed-loop time constant, λ, is also suggested for the FOPDT and SOPDT models.     

高速模糊PID温度控制器的设计与实现

模糊-PID控制器由于其较高的精度与优良的动态响应性能而获得了广泛应用,实现方法多为基于单片机技术的软件实现,其实时性与抗干扰性能并不理想。采用EDA技术,以FPGA为基础,设计了一款硬件模糊-PID控制器,很好地克服了软件实现方案的上述缺点。当采样温度与设定值的差值在一定范围内时,采用经典PID控制以消除系统的动态误差;当差值大于某一范围时,采用模糊控制以获得可靠的控制精度。通过Verilog仿真分析,证明了其上述优点,具有较高的实用价值。     

基于资格轨迹的电缆线径控制

针对具有滞后特性的电缆绝缘挤出机,设计了一种基于Sherman Morrison和Sarsa(λ)的预测型强化学习控制器SM-Sarsa(λ)控制挤出直径。该控制器主要包含两个过程,一是以Sarsa(λ)为核心的决策过程,另一个是以Sherman Morrison为关键技术的拟合过程。两者相互配合,一方面决策过程可以为拟合过程提供样本数据得到预测模型,以便跟踪系统的传递函数,另一方面预测-学习过程通过拟合模型为决策-学习过程提供预测值,以便在等效无滞后的条件下进行实时控制。将SM-Sarsa(λ)与传统控制器进行仿真对比实验,结果表明:SM-Sarsa(λ)在牺牲一定训练时间的代价下,其控制效果明显优于传统控制器。采用该控制器的电缆绝缘挤出机,响应速度和收敛速度更快、超调量小,控制精度大幅度提高。     

A study on the adaptive predictive control method for multivariable bilinear processes

A predictive control method for multivariable bilinear processes is derived based on ARMA model. To identify bilinear process models, we use simple equation error method extended to multivariable system. We can obtain the adaptive predictive controller for multivariable bilinear processes by incorporation of the identification algorithm. Offset compensator is provided to correct for the effects of unmeasured disturbances and model inaccuracies. A filter with a singled parameter is used to correct for the effects of an incorrect model. Results of simulation on multivariable bilinear processes show that the proposed control method has satisfactory performance.     

PID CONTROLLER TUNING FOR UNSTABLE SYSTEMS BY OPTIMIZATION METHOD

Simple Tuning formulae are provided for optimal PID controller settings for unstable first order plus time delay systems. The method is based on minimization of integral squared errors (ISE). A method of calculating the set point weighting parameter is proposed to reduce the overshoot for servo problems. The performances of the proposed PID settings are compared with the settings recently proposed by Huang and Chen (1997, 1999) for both the servo and regulatory problems. The performance of the controller is also evaluated under parameter uncertainty in time delay and separately in process gain. Tuning formulae are given for PI controller along with the set point weighting. The performance of the PI controller is compared with that of Poulin and Pomerleau (1996). Two simulation studies, one on control of an unstable nonlinear bioreactor and a second on an unstable chemical reactor using the proposed PID controller settings, show improved performances both for servo and regulatory problems.     

Decentralized fault-tolerant control system design for unstable processes

Fault-tolerant control is an important issue in control of mission critical processes. In this paper, a new approach to fault-tolerant control of unstable processes is proposed based on the Passivity Theorem. The control system is designed in two sequential steps: A multi-loop proportional controller is used to stabilize the unstable process; a passivity-based decentralized unconditionally stabilizing (DUS) controller is then applied to the stabilized process. While the multi-loop stabilizing controllers need to be built with redundancy, the DUS controller is inherently fault tolerant and can maintain closed-loop stability when any of its loops fail. By using a stabilizing proportional controller with the fewest loops, control redundancy can be reduced to the minimum level.