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提出一种评估带前馈的PID控制回路的控制器性能的方法.该方法通过求取在最优前馈和反馈控制器作用下的最小过程输出方差,并将其与实际的输出方差比较,以评估控制器的性能,同时可以得到实现该最小方差的最优PID控制器的参数.仿真结果表明,引入前馈作用可以改善PID控制回路的性能,并且采用本文提出的评估方法可以得到一个合理的评估结果. 相似文献
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流程工业的控制回路中90%以上都使用PID控制器,在线PID参数整定方法一直是一个有很大意义却比较难解决的工程问题。PID最小方差性能评价常用于评价控制性能,然而其得出的最优PID参数往往并不适用于实际系统,当出现问题时需要重新加阶跃响应整定PID参数。将PID最小方差控制和系统传统的动态性能指针评价方法结合使用,通过系统传统的动态性能指针的要求给出PID参数的取值范围,再根据过程输出方差随PID参数变化而变化的趋势整定PID参数,该方法在实验装置的参数整定中得到了验证。 相似文献
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化工过程一般为多变量系统,但其主要控制方案为分散多回路PID常规控制。由于多变量系统内部存在不同程度的耦合作用,各控制回路之间存在相互影响,当其他回路进行手动/自动模式切换时,本回路等效被控对象将会发生突变,导致本回路的原有控制参数不能适应等效被控对象的变化,造成控制性能下降,甚至闭环系统不稳定。为避免这种情况的发生,从整个系统的角度研究控制回路模式切换时的稳定性,采用多变量频域Nyquist阵列设计法。基于对角优势下正Nyquist稳定性判据,从Gershgorin圆边界点的角度定量分析各个控制回路在模式切换前后的稳定性变化程度,从而确定各回路控制器增益的调整方向及程度,实现各回路的控制器参数在控制回路模式切换瞬间的自动整定,尽可能抵消控制回路模式切换对整个系统的扰动,保证整个系统的闭环稳定性。以Shell公司重油分馏塔的多回路PID控制系统为例,将3个PID控制回路依次投用时,根据Gershgorin圆边界点进行控制参数的自整定,闭环系统仍能保持一定的控制性能,否则闭环系统将不稳定。 相似文献
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PLC在塑料挤出机温度控制系统中的应用 总被引:9,自引:0,他引:9
介绍了SIMATIC S7-300可编程控制器在塑料挤出机温度控制系统中的应用,控制回路采用PID参数自整定和脉宽调功法,控制系统把传统的PID控制和PLC的逻辑判断指令结合起来,使PID控制更为灵活,能满足生产过程的要求。详细描述了系统的工作原理和PLC的硬件组成、软件编制,简单介绍了上位机的组态软件WinCC。 相似文献
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传统的解耦控制方法由于其过于依赖模型辨识等问题难以被实际应用,且存在成熟系统不宜进行控制器再设计等问题,此外,回路解耦控制的专家经验难以提取与传承。因此以等效传函理论为研究基础,提出了一种面向解耦问题的基于序列决策的PID参数整定方法,提取历史数据中经验丰富的操作人员的控制序列。在解决回路之间存在耦合而使控制效果不佳的问题的同时,使工程人员的PID参数整定经验数字化得以传承,辅助初级人员进行操作。最后将所提方法应用于Matlab和Aspen两个仿真平台的耦合回路系统,获得满意结果,并验证所提方法的有效性和正确性。 相似文献
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传统的解耦控制方法由于其过于依赖模型辨识等问题难以被实际应用,且存在成熟系统不宜进行控制器再设计等问题,此外,回路解耦控制的专家经验难以提取与传承。因此以等效传函理论为研究基础,提出了一种面向解耦问题的基于序列决策的PID参数整定方法,提取历史数据中经验丰富的操作人员的控制序列。在解决回路之间存在耦合而使控制效果不佳的问题的同时,使工程人员的PID参数整定经验数字化得以传承,辅助初级人员进行操作。最后将所提方法应用于Matlab和Aspen两个仿真平台的耦合回路系统,获得满意结果,并验证所提方法的有效性和正确性。 相似文献
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化工过程全流程为具有高维输入输出的多变量大系统,内部存在一定程度的耦合作用,因此其底层常规PID控制系统的设计、投用和整定也必然与整个系统的耦合程度有关。首先,提出了闭环相对增益和耦合度的概念,分析闭环相对增益在理想控制条件下与开环相对增益的等效性,发现闭环控制回路的反馈作用引起操纵变量和被控变量的关联,由此加剧整个系统的耦合程度,因此闭环控制回路并非投用得越多越好。然后,提出了基于闭环耦合度的化工过程大系统常规PID控制回路的投用规则,根据被控过程开环相对增益阵确定控制回路变量配对和投用顺序,依次投用各控制回路并计算控制回路的耦合度,当耦合度超过阈值时停止剩余控制回路的投用。最后,以典型多变量TE过程为例验证了该投用规则的有效性。 相似文献
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针对工业广泛应用的PID控制器,提出一种PID控制器性能评价及鲁棒参数优化的设计方法,该方法将PID控制器性能评价与鲁棒参数整定问题转化为线性矩阵不等式(LMI)凸优化问题进行求解,并利用所提方法开发了工业应用注册软件. 相似文献
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A tuning method of multiloop PID controllers is developed based on the generalized IMC PID tuning rule by Lee et al. (1998a).
To extend the SISO PID tuning method to MIMO systems, a new tuning criterion is proposed. The criterion is based on the closed
loop frequency response method to meet desired performance and robustness as close as possible. Examples for 2x2, 3x3 and
4x4 systems are used to illustrate the proposed method. The results show that the proposed method is superior to conventional
methods such as the BLT tuning method. 相似文献
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徐志成 《化工自动化及仪表》2006,33(5):22-25
针对复杂工业过程中存在的一类模型不确定问题,提出一种新的鲁棒PID控制器参数整定方法.通过将鲁棒PID控制器的参数整定问题转化成一个max-min优化问题,利用微粒群优化(PSO)的协作算法对之进行求解,能获得某种鲁棒性能指标最优的PID控制器.对连续搅拌反应釜系统的实例仿真结果表明:与其它典型鲁棒PID控制器设计方法相比,本方法得到的PID控制器具有更强的鲁棒性和抗干扰能力,当过程操作范围发生大的变化时,利用本方法设计的鲁棒PID控制器能获得满意的结果. 相似文献
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The derivative mode is often omitted in PID control strategies because it proves difficult to arrive by trial‐and‐error at a set of constants which meet plant requirements. The primary objective of this paper was to evaluate several model‐based PID tuning methods. For lag‐dominant processes, it was recommended that the SIMC algorithm first be employed to determine whether satisfactory performance can be obtained with PI control. If it cannot, then derivative action should be introduced using the DS‐d technique. For delay‐dominant systems, IMC tuning is preferred. It was observed that when configured with the same derivative filter factor, the series form of the PID controller produces smoother valve adjustments than the parallel version, at the expense of a slight decrease in best achievable performance. Increasing this parameter improves the control effort but limits achievable performance. 相似文献
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I-LUNG CHIEN HSIAO-PING HUANG JEN-CHIEN YANG 《Chemical Engineering Communications》2013,200(1):181-196
A simple tuning method for TITO (Two-Input, Two-Output) PI controllers will be presented in this article. The method is an extension of the SISO PID tuning method based on Internal Model Control (IMC). An approximate model for tuning purpose will be developed using the information from the interaction measure of the TITO system. The procedure of the tuning method is very simple and straightforward utilizing only two bias-relay feedback tests. The tuning method can easily be applied to various industrial situations with almost no need for a priori process knowledge. Various TITO examples will be used to demonstrate the performance of this tuning method. Both setpoint and load disturbance responses will be examined 相似文献
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研究有常数网络诱导时延的一类典型网络化串级控制系统的PID控制器参数整定问题。系统中的网络诱导时延为常数,主对象和副对象均为一阶惯性加纯迟延环节(FOPDT)。主控制器是有超前滞后校正环节的PID,副控制器是带有滤波环节的PID。基于过程模型和期望闭环系统响应整定PID参数,采用一阶P偄de近似纯迟延环节,以解析的形式推导出了主控制器和副控制器整定参数的表达式,并采用双线性变换法得到离散时间PID控制器。提出了网络化串级控制系统的控制性能综合指标,并基于TrueTime工具箱在不同网络诱导时延时对网络化串级控制系统进行了仿真研究。仿真结果和性能指标计算结果均验证了所提算法的可行性和有效性。 相似文献
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Doe Gyoon Koo Jietae Lee Dong Kwon Lee Chonghun Han Lyu Sung Gyu Jae Hak Jung Moonyong Lee 《Korean Journal of Chemical Engineering》2001,18(4):451-455
Many industrial chemical process control systems consist of conventional PID and nonlinear controllers, even though many advanced
control strategies have been proposed. In addition, nonlinear control methods are widely used even for linear processes to
achieve better control performance compared with linear PID controllers. However, there are few tuning methods for these nonlinear
controllers. In this work, we suggest new controller tuning methods for the error square type of nonlinear PI controller.
These control methods can be applied to a large number of linear and nonlinear processes without changing control structures.
We also propose new tuning rules for integrating processes. In addition, we suggest application guidelines for performing
the proposed tuning rules at the pilot scale multistage level control system. Finally, in this work we confirmed good control
performances of the proposed tuning methods through both simulation studies and experimental studies. 相似文献
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This paper presents a novel method for proportional-integral-derivative (PID) controller tuning directly using the step response data of the process without resorting to a process model. The required process data are collected from a one-shot step test that can be conducted under either closed-loop or open-loop conditions. The proposed method derives the PID parameters so that the resulting control system behaves as closely as possible to the prescribed reference model. Two structures of the reference model are considered for general design and improved disturbance rejection, respectively. A simple one-dimensional optimization problem is formulated to determine an appropriate reference model for the controlled process. Moreover, the proposed PID tuning method includes a robustness specification based on the maximum peak of sensitivity function that enables the user to explicitly address the trade-off between performance and robustness. Simulation examples are provided to illustrate the superiority of the proposed method over existing (model-based) tuning methods. 相似文献
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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. 相似文献
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DESIGNING PID CONTROLLERS WITH A MINIMUM IAE CRITERION BY A DIFFERENTIAL EVOLUTION ALGORITHM 总被引:5,自引:0,他引:5
Although the integral of absolute error (IAE) has long been used as a performance measure for controller evaluation, a systematic approach is still lacking for the design of optimal PID controller with the minimum IAE performance criterion. This may be ascribed to the nonsmoothness of the IAE objective function and the lack of closed-form expression for the IAE performance index. In this paper, we propose the use of a differential evolution algorithm (DEA) to design a minimum-IAE PID controller to overcome the nondifferentiability of the IAE objective function. To achieve also a specified least relative stability margin and least damping ratio, the D-partition technique is used to identify the allowable domain in the tuning parameter space. Three examples are provided to illustrate the effectiveness of the DEA. 相似文献