主蒸汽温度预测PID串级控制应用研究

目前火电厂主汽温热工自动控制系统普遍使用的传统PID控制,难以在非线性、惯性、迟延、时变和扰动等特性下达到满意的控制效果.给出了一种PFC-PID串级控制方案,该方案采用双闭环控制,结合了传统PID控制和PFC控制的优点,现实了鲁棒性、精度和快速性等较好的控制效果.分析了该算法的原理和设计过程,MATLAB仿真结果表明,其较传统的控制算法有更好的鲁棒性和抗干扰性.预测PID串级控制算法对火电厂主汽温控制将有十分广阔的应用前景.     

基于小波变换的非线性广义预测控制

提出了基于小波变换的非线性广义预测控制算法。预测模型采用Hammerstein模型,对于其静态非线性部分采用小波网络来辨识,动态线性部分用最小二乘法来辨识。这种辨识方法比传统的多项式拟合的模型误差要小得多。基于这种预测模型广义预测控制器弥补了传统广义预测控制的模型失配问题。以CSTR为例对所设计的控制器进行仿真研究,结果表明控制器能够取得良好的控制效果。     

Wavelet neural adaptive proportional plus conventional integral-derivative controller design of SSSC for transient stability improvement

Although the PI or PID (PI/PID) controllers have many advantages, their control performance may be degraded when the controlled object is highly nonlinear and uncertain; the main problem is related to static nature of fixed-gain PI/PID controllers. This work aims to propose a wavelet neural adaptive proportional plus conventional integral-derivative (WNAP+ID) controller to solve the PI/PID controller problems. To create an adaptive nature for PI/PID controller and for online processing of the error signal, this work subtly employs a one to one offline trained self-recurrent wavelet neural network as a processing unit (SRWNN-PU) in series connection with the fixed-proportional gain of conventional PI/PID controller. Offline training of the SRWNN-PU can be performed with any virtual training samples, independent of plant data, and it is thus possible to use a generalized SRWNN-PU for any systems. Employing a SRWNN-identifier (SRWNNI), the SRWNN-PU parameters are then updated online to process the error signal and minimize a control cost function in real-time operation. Although the proposed WNAP+ID is not limited to power system applications, it is used as supplementary damping controller of static synchronous series compensator (SSSC) of two SSSC-aided power systems to enhance the transient stability. The nonlinear time-domain simulation and system performance characteristics in terms of ITAE revealed that the WNAP+ID has more control proficiency in comparison to PID controller. As additional simulations, the features of the proposed controller are compared to those of the literature while some of its promising features like its fast noise-rejection ability and its high online adapting ability are also highlighted.     

液压伺服系统的预测函数控制及其仿真研究

为了提高液压伺服系统的跟踪性能和鲁棒性,将预测函数控制(PFC)和PID控制的优点相结合,提出了一种PFC-PID串级控制策略.内环采用PID控制来提高抗十扰性,把内环作为外环PFC控制的广义对象,对广义对象进行拟合简化得到一阶加纯滞后系统,作为PFC的预测模型,外环采用PFC来获得良好的跟踪性能和鲁棒性.通过Matlab建模、仿真及与PID控制的比较表明,PFC-PID串级控制策略能够改善液压伺服系统的控制性能.     

Adaptive speed control based on just-in-time learning technique for permanent magnet synchronous linear motor

In this paper, an adaptive two degrees of freedom (2Dof) PI controller based on a just-in-time learning (JITL) method is proposed for predictive speed control of permanent magnet synchronous linear motor (PMSLM). Firstly, to guarantee the high identification accuracy and high real-time performance simultaneously, an improved JITL method is proposed to estimate the controlled model parameters of speed control system. Then, based on the dynamic controlled model, a simplified generalized predictive control (GPC) supplies a 2Dof proportional integral (PI) controller with suitable control parameters to follow a sinusoid-type speed command in operating conditions. The main motivation of this paper is the extension of the predictive controller to replace traditional PI controller in industrial applications. Finally, the efficacy and usefulness of the proposed controller are verified through the experimental results.     

一种自调节灰色预测PID控制器

为提高传统PID控制的性能及扩大其适用范围,提出一种结合传统PID控制、灰色预测和全程快速非线性跟踪．微分器的自调节灰色预测PID控制器。利用灰色预测对系统的输出偏差和预测偏差进行合成形成一个综合偏差,用来代替传统PID控制中的实际偏差项。这样控制器既有预测系统未来行为的功能,又能根据预测模型精度自动调节控制器参数,能有效减小预测误差对系统的不利影响。同时用非线性跟踪．微分器代替差分法来提取微分信号,提高了微分信号的品质。仿真结果表明,与传统PID控制器相比,该控制器可获得更为优良的动态性能。     

一种PID模糊控制器(fuzzy PI+fuzzy ID型)

提出一种二维PID模糊控制器,其结构形式筒称为fuzzy PI+fuzzy ID型.根据fuzzy PI和fuzzy ID控制器的图解说明,确定该fuzzy PI和fuzzy ID控制器的模糊控制规则的相似性.理论分析表明,该PID模糊控制器除具有常规PID性能外,还具有非线性等特点.仿真结果表明,与常规PID和fuzzy PI控制相比性能更优.     

大滞后系统模糊自适应PI-Smith控制

工业过程中普遍存在大时滞对象,为了解决大时滞系统控制中超调量大和调节时间长等问题,将史密斯(Smith)预估控制原理和模糊PI控制器参数的自适应调整方法结合起来,在Smith预估控制系统中,用模糊PI控制器代替传统的PID控制器,根据模糊控制原理对PI的2个参数进行在线整定,提出一种大时滞系统的模糊自适应PI-Smith控制方法.通过对电加热炉的仿真研究,结果表明该方法具有调节时间短、无超调量、控制精度高、无稳态偏差的优点,同时对系统模型变化具有良好的适应性.     

A model-based augmented PID algorithm

For complex control problems, advanced techniques, such as model-based predictive control may give better control performance than the common PID controller. However, the extra complexity and limited support of control software especially at the distributed control system (DCS) level, may prohibit the application of advanced algorithms. Also, implementing model based control often requires a higher level of programming than is readily available at the DCS level. This paper addresses this problem by providing a control algorithm utilizing multiple DCS PID blocks to implement a model-based predictive control strategy. The approach was tested on process simulations and the algorithm was able to provide control performance similar to that of generalized predictive control.     

基于PSO优化的燃油供给压力动态跟踪控制

燃烧用油料供给压力的精确控制是一个具有非线性特性的流体输送压力控制问题,针对现有PID控制存在的不足,提出了基于PSO优化的预测函数控制(PSO-PFC)方法,通过与PFC,PID控制方法的仿真比较,以及对阳极焙烧炉重油燃烧供给压力的动态跟踪控制表明,该方法优于原有燃油燃烧系统的PID控制,以及常规和其他改进的PFC控制方法,实现了燃油供给压力的动态跟踪精确控制。     

基于BF-PSO的船舶电站柴油机分数阶控制器

针对船舶电力系统的频率稳定性问题,对船舶电站柴油机调速系统设计了分数阶PIλDμ控制器。采用细菌觅食-粒子群混合优化(BF-PSO)算法对分数阶PIλDμ控制器参数进行优化整定,解决了分数阶PIλDμ控制器整定参数多、设计复杂的问题。对分别采用分数阶PIλDμ控制器和传统整数阶PID控制器的柴油机调速系统进行了仿真和对比。结果表明,在同等条件下优化得到的分数阶PIλDμ控制器能够有效抑制模型参数摄动,鲁棒性更强,具有更好的控制效果。     

Gpc‐Based Self‐Tuning PI Controller for Speed Servo System of PMSLM

In this paper, a generalized predictive control (GPC)‐based two degrees of freedom (2 DOF) proportional integral (PI) controller is proposed for the speed servo system of a permanent magnet synchronous linear motor (PMSLM). In this new approach, based on a dynamic model of a servo system, a simplified and high‐performance GPC supplies a 2 DOF PI controller with suitable control parameters, according to the varied operating conditions. In previous studies, GPC‐based proportional integral derivative (PID) controllers have been designed using a step‐type or ramp‐type reference input. In our work, however, the speed command for PMSLM usually is required to be a trapezium‐type signal because of the limited travel range. Hence, control performance of a speed servo system using a GPC‐based 2 DOF PI controller is enhanced for tracking a trapezium‐type command. The validity and usefulness of the proposed controller are verified through simulation and experiments.     

An alternative structure for next generation regulatory controllers: Part I: Basic theory for design, development and implementation

Even though employed widely in industrial practice, the popular PID controller has weaknesses that limit its achievable performance, and an intrinsic structure that makes tuning not only more complex than necessary, but also less transparent with respect to the key attributes of the overall controller performance, namely: robustness, set-point tracking, and disturbance rejection. In this paper, we propose an alternative control scheme that combines the simplicity of the PID controller with the versatility of model predictive control (MPC) while avoiding the tuning problems associated with both. The tuning parameters of the proposed control scheme are related directly to the controller performance attributes; they are normalized to lie between 0 and 1; and they arise naturally from the formulation in a manner that makes it possible to tune the controller directly for each performance attribute independently. The result is a controller that can be designed and implemented much more directly and transparently, and one that outperforms the classical PID controller both in set-point tracking and disturbance rejection while using precisely the same process reaction curve information required to tune PID controllers. The design, implementation and performance of the controller are demonstrated via simulation on a nonlinear polymerization process.     

PID控制器参数调整的滚动优化算法

A novel supervised receding horizon optimal scheme is presented for discrete time systems in the process control. In the employing level, PID controller is used, while the receding horizon approach is applied to the optimized level. The considered problem is to optimize the employing level PID controller parameters through minimizing a generalized predictive control criterion. Compared with a fixed parameters PID controller, the proposed algorithm provides well performance over a range of operating condition.     

Receding Horizon Optimization Approach to PID Controller Parameters Auto-tuning

A novel supervised receding horizon optimal scheme is presented for discrete time systems in the process control.In the employing level,PID controller is used,while the receding horizon approach is applied to the optimized level.The considered problem is to optimize the employing level PID controller parameters through minimizing a generalized predictive control criterion.Compared with a fixed parameters PID controller,the proposed algorithm provides well performance over a range of operating condition.     

模糊PID复合控制在变频空调中应用研究

空调房间温度控制是一复杂的控制过程,传统的模糊或PID控制很难得到较好的控制效果,模糊控制和PID控制适当结合控制空调房间温度可使控制效果大大提高。本文建立了房间温度控制模型,介绍了模糊和PID控制并联结合方式并对各复合控制器进行了设计。对设计的变频空调控制系统进行了仿真,结合仿真图,从鲁棒性和稳定性方面分析了设计的各模糊和PID复合控制器控制效果。     

基于预测控制的刨花板施胶比值系统研究

在刨花板生产线施胶过程中,刨花施胶精度对刨花板的物理性能和环保性能影响较大。为了提高刨花施胶效果,设计了基于KPFC-PI的比值控制系统,将比值器和PFC作为控制系统外环,用以提高胶液流量按照比值工艺跟踪刨花流量的速度和鲁棒性,系统内环路采用PI控制器,增强系统抗干扰性,并通过调节PI参数,拟合简化整个内环路,作为外环PFC的一阶加纯滞后广义处理对象,用来减少干扰引起的偏差。通过仿真实验,说明了该控制器与PID控制相比,可有效提高刨花板施胶精度、保持施胶量稳定性和具有较强抗干扰性能。     

一类非线性系统的自适应预测函数控制

针对一类具有输出反馈耦合的离散非线性系统,将过程的非线性状态空间模型等效为线性时变状态空间模型;然后利用最小二乘法辨识系统参数,并通过在目标函数中引入系统状态的变化给出一种具有类似离散PI最优调节器结构的新型自适应预测函数控制器．由于引入了新的优化目标函数,该控制器控制效果与鲁棒性要优于仅考虑预测输出误差的传统预测函数控制器．仿真结果表明,该控制器优于经典离散PI最优调节器．     

基于模糊分数阶PIλDμ控制的AC/DC变换器

作为AC/DC电力变换装置的核心,控制系统控制效果的好坏直接影响电压输出波形的质量.为了进一步提高AC/DC电力变换装置的控制性能,增强系统的鲁棒性和稳态性,提出一种模糊控制与分数阶PIλ Dμ控制相结合的复合控制策略,并将其用于十二脉波整流电路的控制系统中.采用模糊控制器可以很好地实现对控制参数的自适应调整,分数阶PIλDμ控制器在非线性系统的控制过程中能够取得比整数阶PID控制器更好的控制效果.仿真和实验结果表明,改进后的控制器具有较强的灵活性和鲁棒性,稳态性和自适应能力得到增强,适用于非线性时变系统.     

Parallel Fuzzy P＋Fuzzy I＋Fuzzy D Controller： Design and Performance Evaluation

In this paper, a parallel fuzzy proportional plus fuzzy integral plus fuzzy derivative (FP+FI+FD) controller is proposed. It is derived from the conventional parallel proportional-integral-derivative (PID) controller. It preserves the linear structure of a conventional parallel PID controller, with analytical formulas. The final shape of the controller is a discrete-time fuzzy version of a conventional parallel PID controller. Computer simulations are performed to evaluate the performance of the FP+FI+FD controller for setpoint tracking and load-disturbance rejection for some complex processes, such as first- and second-order processes with delay, inverse response process with and without delay and higher order processes. Also, the performance of the proposed fuzzy controller is evaluated experimentally on highly nonlinear liquid-flow process with a hysteresis characteristic due to a pneumatic control valve. The simulation and real time control is done using National Instrument hardware and software (LabVIEW). The response of the FP+FI+FD controller is compared with the conventional parallel PID controller, tuned with the Ziegler-Nichols (Z-H) and Astrom-Hagglund (A-H) tuning technique. It is observed that the FP+FI+FD controller performed much better than the conventional PI/PID controller. Simulation and experimental results demonstrate the effectiveness of the proposed parallel FP+FI+FD controller.