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.     

加热炉分数阶PID温度自适应控制系统设计

针对加热炉温度控制系统控制器参数不易选择的问题，提出一种分数阶自适应PID串级控制方法实现控制器参数自动调整。首先以分数阶PID控制器分别作为温度主控制器和燃气流量控制器，实现加热炉串级温度控制；其次应用自适应理论对控制器进行改进，设计了自适应分数阶PID控制器。最后通过数值仿真，验证了所设计控制系统对加热炉温度控制的有效性和可行性。     

分数阶控制器在过热汽温控制中的应用研究

在传统串级控制基础上结合分数阶PIλ Dμ控制器,提出过热汽温的分数阶PIλDμ串级控制策略.采用粒子群优化算法对分数阶PIλ Dμ控制器参数进行整定.在Matlab/Simulink仿真环境中对分数阶PIλDμ控制器和整数阶PID控制器的控制效果进行仿真对比,结果表明分数阶pIλ Dμ控制器在设定值跟踪、扰动抑制和鲁...     

模糊自适应PI控制在空调系统中的研究

以空气焓差法试验台空调系统的温度控制系统为具体仿真对象建立了数学模型,该空调系统可以看作是一阶惯性加纯滞后的环节,而且对象的过程参数和时延时间是时变的,传统的PID控制无法获得理想的控制效果。提出了一种无需辨识环节的具有智能的模糊自适应PI的控制算法并将其应用在该空调系统中,该算法对模糊控制和PI控制进行有机结合,根据实际控制经验,通过模糊控制规则对控制回路中PI控制器的参数进行实时整定,并将该控制算法和经过良好整定的PI控制器在空调系统中的控制性能进行比较。仿真结果表明,模糊自适应PI控制提高了系统的鲁棒性、减小了超调量、提高了抗干扰能力、缩短了调整时间。     

PID参数自整定条件下的液位控制系统设计研究

为了优化液位控制系统设计方案，将可视化分析、限定控制范围内自动化控制、串级控制3项技术融为一体，设计一套完整的液位控制系统。该系统采用PID参数自整定方法，创造液位控制条件，增加储油箱，设计双容液位控制系统，通过串级控制，以副控制环节带动主控制回路，提高液位控制精度。系统测试结果显示，本系统作业期间各项指标皆达到标准，PID参数整定条件下的控制效果良好。     

一类网络化串级控制系统的性能分析

基于工业过程控制实际,引入了网络化串级控制系统的概念,并指出了网络化串级控制系统的四种典型拓扑结构.针对其中的一类具有不同性质网络诱导时延的网络化串级控制系统,研究了将传统的离散时间控制方法应用于网络化串级控制系统闭环系统建模的可行性.将控制方法分为同步和异步两种,提出了系统的性能损失指标,同步和异步控制时的系统仿真结果表明异步控制所得到的性能优于同步控制的性能.从而推导出结论网络化串级控制系统的分析与设计需要更多的异步控制方法.     

PID参数自整定方法及其在PVC生产中的应用

介绍了PID控制的理论基础及其参数自整定的基本原理和常规方法,并简述了传统和现行PID参数自整定的原理及策略,把前馈、串级控制系统和按计算指标控制的控制系统等涉及自整定PID控制器应用于新疆天业股份有限公司26万t/a PVC装置的DCS集散控制系统中,为生产装置正常运行、节能降耗,保证安全生产,提高产品质量起了决定作用。     

PID参数工程整定方法研究

本文分析了PID控制模型中比例积分微分的作用,介绍了传统PID参数整定的方法,并总结了PID参数经验整定方法,应用该方法对碱液降膜蒸发流量液位串级控制系统主调和副调PID参数进行调整,并取得了较稳定的控制效果。     

改进型单级三冲量汽包水位控制系统应用研究

结合工程实例,分析了串级三冲量与单级三冲量控制系统原理和DCS组态实现,指出了串级三冲量控制系统在工况条件下PID参数整定存在的问题,提出了一种改进型单级三冲量控制系统。生产实践表明:该系统稳定可靠,PID参数整定更加简单快捷,操作方便且控制效果好。     

一阶时滞不稳定对象的PID控制器多目标优化设计

针对一阶时滞（FOPDT）不稳定对象,提出了一种基于参数稳定空间的多目标遗传算法进行PID控制器的优化设计。该算法首先采用两级控制结构,以保证PID控制器参数稳定空间的存在性,然后,基于该稳定空间提出了一种多目标遗传算法,用来求解带约束的多目标PID控制器参数整定问题。数值例子和生物反应器仿真研究表明所提方法的有效性。     

计量泵行程调节的鲁棒非脆弱PID控制器设计

This job focuses on the stroke regulation of a class of high-precision metering pumps.A parametertuning method of robust non-fragile PID(proportional-integral-derivative)controllers is proposed with the assumption that a PID controller has additive gain perturbations.An H-infinite robust PID controller can be obtained by solving a linear matrix inequality.This approach can guarantee that the closed-loop control systems is asymptotically stable and the H-infinite norm of the transfer function from the disturbance to the output of a controlled system is less than a given constant to attenuate disturbances.The simulation case shows that the control performance of the proposed strategy is significantly better than the traditional PID approach in the situation with perturbations of controller parameters.     

Performance assessment of cascade controllers for nitrate control in a wastewater treatment process

A cascade control strategy is proposed to the benchmark simulation model 1 (BSM1) to enhance the treatment performance of nitrogen removal in a biological wastewater treatment plant. The proposed control approach consists of two control loops, a primary outer loop and a secondary inner loop. The method has two controllers of which the primary loop has a model predictive control (MPC) controller and the secondary loop has a proportional-integralderivative (PID) controller, which is a cascade MPC-PID controller. The primary MPC controller is to control the nitrate concentration in the effluent, and the secondary PID controller is to control the nitrate concentration in the final anoxic compartment. The proposed method controls the nitrate concentrations in the effluent as well as in the final anoxic reactor simultaneously to strictly satisfy the quality of the effluent as well as to remove the effects of disturbances more quickly by manipulating the external carbon dosage rate. Because the control performance assessment (CPA) technique has the features of determining the capability of the current controller and locating the best achievable performance, the other novelty of this paper is to suggest a relative closed-loop potential index (RCPI) which updates the CPA technology into a closed-loop cascade controller. The proposed method is compared with a cascade PID-PID control strategy and the original PID controller in BSM1 and an improved performance of the suggested cascade MPC-PID controller is obtained by using the CPA approach.     

A tuning of the nonlinear PI controller and its experimental application

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.     

基于LMI的鲁棒PID控制器设计及工业应用

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.     

An automatic pid controller tuning method by frequency response techniques

An alternative Ziegler-Nichols (1942) controller tuning technique was proposed in this study. Under the proportional control of a single-loop control system, an arbitrary pulse testing in the set point was introduced to the system. The ultimate frequency and gain could both be directly calculated from the transients by frequency response techniques without any trial and error procedures. PID controller settings were thus obtained according to the Ziegler and Nichols' rules. Furthermore, this technique was extended to the tuning of a cascade control system. A procedure for simultaneously tuning the primary and secondary controllers with both loops in proportional control from a single pulse testing also is presented.     

A model predictive functional control based on proportional-integral-derivative (PID) and proportional-integral-proportional-derivative (PIPD) using extended non-minimal state space: Application to a molten carbonate fuel cell process

The performance of most controllers, including proportional-integral-derivative (PID) and proportional-integral-proportional-derivative (PIPD) controllers, depends upon tuning of control parameters. In this study, we propose a novel tuning strategy for PID and PIPD controllers whose control parameters are tuned using the extended non-minimal state space model predictive functional control (ENMSSPFC) scheme based on the auto-regressive moving average (ARMA) model. The proposed control method is applied numerically in the operation of the MCFC process with the parameters of PID and PIPD controllers being optimized by ENMSSPFC based on the ARMA model for the MCFC process. Numerical simulations were carried out to assess the set-point tracking performance and disturbance rejection performance both for the perfect plant model, which represents the ideal case, and for the imperfect plant model, which is usual in practical applications. When there exists uncertainty in the plant model, the PIPD controller exhibits better overall control performance compared to the PID controller.     

A unified approach to the design of advanced proportional-integral-derivative controllers for time-delay processes

A unified approach for the design of proportional-integral-derivative (PID) controllers cascaded with first-order lead-lag filters is proposed for various time-delay processes. The proposed controller’s tuning rules are directly derived using the Padé approximation on the basis of internal model control (IMC) for enhanced stability against disturbances. A two-degrees-of-freedom (2DOF) control scheme is employed to cope with both regulatory and servo problems. Simulation is conducted for a broad range of stable, integrating, and unstable processes with time delays. Each simulated controller is tuned to have the same degree of robustness in terms of maximum sensitivity (Ms). The results demonstrate that the proposed controller provides superior disturbance rejection and set-point tracking when compared with recently published PID-type controllers. Controllers’ robustness is investigated through the simultaneous introduction of perturbation uncertainties to all process parameters to obtain worst-case process-model mismatch. The process-model mismatch simulation results demonstrate that the proposed method consistently affords superior robustness.     

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.     

OPTIMAL TUNING OF PID CONTROLLERS FOR SINGLE AND CASCADE CONTROL LOOPS

Design of one parameter tuning of three-mode PID controller was developed in this present study. The integral time and the derivative time of the controller were expressed in terms of the time constant and dead time of the process. Only the proportional gain was observed to be dependent on the implemented tunable parameter in which the stable region could be predetermined by the Routh test. Extension of the concept towards designing cascade PID controllers was straightforward such that only two parameters for the inner and outer PID controllers required to be tuned, respectively. The optimal tuning correlative formulas of the proportional gain for single and cascade control systems were obtained by the least square regression method.     

Analytical design of enhanced PID filter controller for integrating and first order unstable processes with time delay

An analytical design for a proportional-integral derivative (PID) controller cascaded with a first order lead/lag filter is proposed for integrating and first order unstable processes with time delay. The design algorithm is based on the internal model control (IMC) criterion, which has a single tuning parameter to adjust the performance and robustness of the controller. A setpoint filter is used to diminish the overshoot in the servo response. In the simulation study, the controllers were tuned to have the same degree of robustness by measuring the maximum sensitivity, Ms, in order to obtain a reasonable comparison. Furthermore, the robustness of the controller was investigated by inserting a perturbation uncertainty in all parameters simultaneously to obtain the worst case model mismatch, and the proposed method showed more robustness against process parameter uncertainty than the other methods. For the selection of the closed-loop time constant, λ, a guideline is also provided over a broad range of time-delay/time-constant ratios. The simulation results obtained for the suggested method were compared with those obtained for other recently published design methods to illustrate the superiority of the proposed method.