输油管道PID控制的影响因素与控制标准

通过对输油管道PID压力控制系统组成与工作原理进行分析,根据工程实践,确定PID压力控制器的数学模型。结合数学模型与现场设备特点,分析影响PID压力控制效果的因素,提出输油管道PID压力控制的参考标准,并通过试验验证了标准的适用性。     

西气东输一线分输压力PID控制效果改进

针对西气东输一线部分站场中电动调节阀压力PID控制效果不佳,导致被控压力不稳,控制效果滞后,阀门频繁动作甚至损坏等问题,对调节阀的压力PID控制逻辑进行分析,在不更换任何硬件的前提下,提出通过优化控制逻辑和参数改进压力PID控制效果的方法。现场测试结果表明:电动调节阀压力PID控制更加稳定,响应速度也更快。     

基于PLC的40T混合磁体低温分配阀箱压力控制系统

基于S7-300 PLC设计混合磁体低温分配阀箱压力控制系统,阀箱内部各处压力控制的PID实现方法相对独立,并未考虑到相互影响。为此,在PID控制方案中加入了前馈控制,使过冷槽压力波动在安全范围内。     

氯碱生产过程中氯氢压力控制分析

介绍了氯碱生产过程中氯氢压力控制方式。重点介绍了:电解槽阴阳极出口压力控制,氯氢总管压力控制,氯氢调节回路PID设置,电解槽跳停氯氢压力的应急控制。控制好氯氢压力,可以提高氯碱生产的稳定性。     

基于PLC的专家PID控制算法在精密压药液压机控制系统中的应用

为了使精密压药液压机控制系统的性能满足军工炸药压制工艺的要求,提出了一种基于PLC的专家PID控制算法。给出系统的控制原理,并将增量式PID控制算法与专家控制器结合通过PLC实现对系统压力的控制。常规PID算法和专家PID算法在实际运行中的结果表明:基于专家PID控制算法的系统压力控制精度高、响应速度快、超调小、抗扰动性能强、鲁棒性好。     

基于PID的直流电动机转速控制系统设计

在传统控制方法下，直接利用当前转速数据计算控制参数，导致控制效果无法满足应用需求，为此，提出基于PID的直流电动机转速控制系统设计研究。在模块设计阶段，设计了数据采集模块、比例调节模块、积分校正模块、微分控制模块、控制衔接模块，五个功能模块协调配合工作，提升直流电动机转速调节控制精度。在软件设计阶段，建立目标函数获取控制偏差；利用模糊规则对PID控制参数进行整定处理，通过二次性能函数计算PID控制装置得到最终输出信号，由此完成直流电动机转速控制系统设计。在测试结果中，系统实现了对直流电动机转速的稳定控制，具有良好的控制效果。     

基于灰色预测模糊PID算法的闪蒸罐压力控制

针对工业生产中闪蒸罐压力控制系统的时变非线性、大滞后等问题,为了提高闪蒸罐压力控制效果,将传统PID控制算法和灰色预测算法相结合,设计出一种基于灰色预测模型的模糊PID控制器。仿真结果表明:它与传统PID控制相比,具有更快的动态响应、调节速度和更好的稳态性能,同时在出现扰动时比模糊PID控制有更好的抗干扰性和更快的调节速度。     

焦炉集气管压力的复合控制

集气管压力的稳定影响焦炭的质量和焦炉的寿命 ,通过分析焦炉集气管压力影响因素及其耦合关系 ,采用PID控制、解耦控制、专家控制来进行集气管压力的控制。应用结果表明 ,集气管压力系统的抗干扰能力得以提高 ,其波动现象得到有效控制     

基于PLC控制的甲醇塔压力参数的控制系统设计

针对甲醇合成塔在实际生产中对压力参数的要求,设计了一套由PLC、变频器、压力传感器、气体压缩机等主要设备构成的变频压力控制系统,具有自动变频运行功能。提出基于PID的压力参数控制方案,解决了传统压力控制方式中存在的问题,增强了系统的可靠性,提升了系统的总体性能。     

陶瓷压砖机的压力闭环控制研究

随着技术的更新迭代,当前液压机械使用比例阀已经是一种常态,但是使用比例阀能不能将压力控制的精准稳定是迫切的需求。本文介绍了通过控制预先控制、PID控制算法来控制比例阀的开口量,从而准确的控制压力,重复性更好,操作便捷,性能更优。     

On-line multivariable adaptive control of a binary distillation column

An experimental evaluation of the simultaneous control of top and bottom product compositions of a binary distillation column utilizing multi-variable self-tuning control algorithms is presented. The study was carried out using an 8-tray, 22.86 cm diameter methanol–water pilot scale column with continuous capacitance analysis of top product composition and bottom composition analyzed on a 3 minute cycle, by a gas chromatograph. Column control is studied for ±25% step disturbances in feed flow rate. Terminal composition regulation using both ‘positional’ and ‘incremental’ forms of a generalized minimum variance self-tuning control algorithm is compared with that achieved using a conventional digital PI/PID multiloop control strategy.     

裂解炉的先进控制

介绍了中国石油大庆石化公司化工一厂乙烯装置GK一Ⅵ型裂解炉的主要控制方案，并结合工艺操作具体说明控制方案的实现过程。     

NONLINEAR MODEL PREDICTIVE CONTROL

Nonlinear Model Predictive Control (NMPC), a strategy for constrained, feedback control of nonlinear processes, has been developed. The algorithm uses a simultaneous solution and optimization approach to determine the open-loop optimal manipulated variable trajectory at each sampling instant. Feedback is incorporated via an estimator, which uses process measurements to infer unmeasured state and disturbance values. These are used by the controller to determine the future optimal control policy. This scheme can be used to control processes described by different kinds of models, such as nonlinear ordinary differential/algebraic equations, partial differential/algebraic equations, integra-differential equations and delay equations. The advantages of the proposed NMPC scheme are demonstrated with the start-up of a non-isothermal, non-adiabatic CSTR with an irreversible, first-order reaction. The set-point corresponds to an open-loop unstable steady state. Comparisons have been made with controllers designed using (1) nonlinear variable transformations, (2) a linear controller tuned using the internal model control approach, and (3) open-loop optimal control. NMPC was able to bring the controlled variable to its set-point quickly and smoothly from a wide variety of initial conditions. Unlike the other controllers, NMPC dealt with constraints in an explicit manner without any degradation in the quality of control. NMPC also demonstrated superior performance in the presence of a moderate amount of error in the model parameters, and the process was brought to its set-point without steady-state offset.     

模糊控制的现状与工程应用关键问题研究

详细阐述了模糊控制技术的研究现状,包括经典模糊控制、智能模糊控制和复合模糊控制。研究分析了模糊控制技术在工程应用中存在的若干问题,包括模糊控制规则和参数优化问题、强耦合多变量问题和模糊控制稳态精度问题,并根据目前国内外模糊控制技术的研究趋势,指出了模糊控制技术未来的研究方向。     

Two-degree-of-freedom output feedback controllers for nonlinear processes

In this work, a nonlinear output feedback control algorithm is proposed, in the spirit of model-state feedback control. The structure provides state estimates using a process model, the measured output, and the residual between the model output and the measured output. These estimates will track the process states at a rate determined by a set of tunable parameters. An algebraic transformation of the state estimates is incorporated in the control structure to ensure that the input/output gain of the observer matches the model upon which the static state feedback control law is based. The transformed states are then used in the control law. This leads to a controller of minimal order possessing integral action. The control structure is shown to have the same properties as the standard model-state feedback structure. The resulting algorithm is a two-degree of freedom control law, in the sense that the control action is not a function of the error only, but the output and the set point are processed in different ways. Finally, a simulation example using an exothermic CSTR operating at an open-loop unstable steady state is used to demonstrate the closed-loop performance of the proposed method.     

轮胎硫化生产过程的模糊控制

分析轮胎硫化生产过程的特点,建立了硫化罐温度和压力控制的多维模糊控制数学模型,设计了适合该模型的控制算法,并在实际工程中予以实现。实践表明该控制方法具有较好的鲁棒性和较好的控制效果,并具有一定的推广价值。     

Two-degree-of-freedom output feedback controllers for discrete-time nonlinear systems

A discrete-time, model-based output feedback control structure for nonlinear processes is developed in the present work. The structure makes use of a closed-loop observer, while at the same time it guarantees that the overall feedback controller possesses integral action. An algebraic transformation is applied on the observer states to insure that the input/output gain of the observer matches the model upon which the static state feedback control law is based. The resulting control algorithm is a two-degree-of-freedom control law, in the sense that the output and the set point are processed in different ways. The control structure is shown not only to have the same properties as the standard model-state feedback structure, but also that it emerges from a model algorithmic control framework. Finally, a simulation example using an exothermic CSTR operating at an open-loop unstable steady state is used to evaluate the closed-loop performance of the proposed method.     

Generic model control — A case study revisited

The application of the Generic Model Control (GMC) algorithm to the control of an evaporator has been reported recently by Lee et al. (1989). The results of their case study are claimed to demonstrate the superiority of the nonlinear GMC algorithm over conventional techniques including Dynamic Matrix Control. In this note it is shown that for the evaporator example the improved performance arises primarily from the full multivariable and feedforward nature of the control law, rather than from the nonlinear nature of GMC.     

Generic model control — A case study

This paper outlines the use of a process model directly in a control algorithm. The process considered, a forced circulation single-stage evaporator, is a nonlinear interacting process. The control strategy employing a process model derived from fundamental mass and energy balances is shown to outperform single loop and predictive control strategies by a significant amount. The control structure is first presented in general form and then specifically applied to this process.     

粗轧控制系统的设计与应用

结合生产实际,对粗轧控制系统进行综合设计。介绍粗轧控制系统的结构,以及粗轧核心APC控制、粗轧RAWC控制和带铜SSC控制的控制思想并给出相应控制算法。