一种新的PID自校正调节器

提出了一种新的ＰＩＤ自校正调节器，这种调节器是基于Ｓｃｈｗａｒｚｅ的系统辨别方法和Ｌａｔｚｅｌ的参数整定方法基础上设计的、仿真实例和实际运行表明该控制器是可行的。     

一种自整定调节器

1引言PID调节器是目前应用最为广泛。具有参数自整定的一种调节器，它不仅能代替人工来自动整定PID参数，而且在对象特性发生变化时，能够对初定的PID参数进行微调，以保证获得良好的调节质量。本文提出一种由系统y识加专家系统的新型自整定调节器，它的基本结构如图1所示。主要由系统y识单元、PID初值设定单元、PID控制单元、参数微调单元等组成。其工作过程如下：（l）系统y识单元，根据阶跃响应特性，求取对象参数。（2）PID初值设定单元，由对象参数计算PID参数，并送PID控制单元，然后断开系统y识单元，使控制系统进入闭环运…     

参数自整定PID控制在电弧炉控制中的应用

在电弧冶炼过程中，大的短路电流和受控模型参数的漂移经典控制难以取得较好的控制效果。本文设计了一个参数自整定ＰＩＥ调节器。它能够有效地克服参数漂移带来的影响，保证系统的稳定性。     

一种非线性PID调节器的设计方法

介绍了一种非线性PID调节器设计方法，由于利用了非线性特性，这种方法克服了快速性和平稳性之间的矛盾，达到了较好的控制效果，通过对交流位置伺服系统的参数设计，验证了其有效性。     

随机系统中满意PID调节器的设计

应用满意控制思想，研究了扇形区域极点和稳态输出方差约束下PID调节器的设计问题．将PID调节器设计问题转化为局部状态反馈问题，再通过适当变换将PID调节器参数设计转化为求解一组线性矩阵不等式的可行解问题，从而可通过MATLAB中的LMI工具箱方便地求解．算例说明了所提出方法的有效性．     

利用非线性特性改进PID控制律

本文综述作者利用非线性特性改进经典ＰＩＤ调节器方面所得的结果，其中有“非线性跟踪－微分器”，“非线性ＰＩＤ控制器”等结构，系统的“时间尺度”，控制器的“适应性”，“鲁棒性”等概念以及这些新结构和概念的应用方法。     

PID控制器在蔬菜发酵系统中的应用

通过试验推导出发酵温控系统的开环传递函数,并且建立了系统的数学模型,同时引入PID控制算法。通过多种PID算法的比较仿真,设计了具有较好特性的PID调节器。     

基于单片机的恒定水位控制系统

针对供水、造纸等行业中的恒定水位系统,提出恒定水位控制的控制方案.在分析电机机械特性的基础上,完成了控制系统结构设计,给出了系统中每一部分的传递函数.采用PID调节器作为转速调节器,实现了数字PID调节器的单片机程序,采用归一参数整定法完成了PID参数整定.实验证明,该水位控制系统能够完成恒水位控制,具有成本低,结构简单等优点.     

一种换热器的变PID参数的整定方法及其实现

在分析换热器热传导过程特性的基础上,讨论了负荷干扰对热器热传导的影响,针对换热器的特性参数随负荷变化而变化的特性,提出一种实时改变控制器PID参数的控制方案,并用KMM可编程调节器加以实现。实验表明,该方案比较常规、固定PID参数的控制系统的抗干扰能力强。     

基于模糊PID原理的液位控制器的设计

分析了液位水平系统具有非线性、上升时间长、滞后现象的特点，讨论了常规PID控制器在控制中的局限性。在常规PID控制器的基础上，引入了模糊逻辑，设计出了一种模糊PID控制器，对PID三个参数进行了在线整定。实验结果表明这种模糊PID控制器具有比常规PID控制器更优良的特性。     

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.     

基于PID和LQR的四旋翼无人机控制系统研究

为提高四旋翼无人机的飞行稳定性、无人飞行器控制系统的鲁棒性和控制精度,以建立的四旋翼无人机飞行控制系统模型为基础,采用现代控制理论与传统控制论相结合的方法,针对姿态角速率、姿态角分别设计内环LQR(线性二次型调节器)控制器,及外环PID控制的双回路闲环控制器.充分利用PID控制器易于掌握且对模型要求精度低、LQR控制器能改善内回路的动态特性和稳态性能的特点,完成四旋翼无人机的飞行控制.通过实验遴选该双闭环控制器相关参数并进行优化,实验结果表明所设计的双回路控制器控制性能指标良好.     

Multivariable integral linear quadratic Gaussian robust control of islanded microgrid to mitigate voltage oscillation for improving transient response

A novel robust integral linear quadratic Gaussian (ILQG) controller is presented in this paper to control the voltage of islanded microgrid and improves its transient response. Microgrid is a small grid that consists of number of distributed generator units, power‐electronic components with inductor‐capacitor (LC) filters and loads. The loads are parametrically uncertain and unknown that produces the voltage or power oscillation. The ILQG controller is capable to compensate for the voltage oscillation and exhibits the tracking of grid voltage against the different load dynamics. The design of ILQG controller is carried out by augmenting the plant dynamics with an integrator. The robustness of the ILQG controller is studied by considering a number of uncertainties within the plant model. The performance of ILQG controller is compared with linear quadratic regulator (LQR) and linear quadratic Gaussian (LQG) controller in terms of rise time, settling time, bandwidth and tracking error. The comparison results ensure the high bandwidth and tracking performance of ILQG controller as compared to other controllers.     

Fault-tolerant control systems design via subdivision of parameter region

This paper presents a linear matrix inequality （LMI） approach to solve the fault-tolerant control （FTC） problem of actuator faults. The range of actuator faults is considered as a parameter region and subdivided into several subregions to achieve a certain desired performance specification. Based on the integral quadratic constraint （IQC） approach, a passive fault-tolerant controller for the whole fault region and multiple fault-tolerant controllers for each fault subregion are designed for guaranteeing stability and improving performance of the FTC system, respectively. According to the estimation of parameters by FDI process, the corresponding subregion controller is chosen for the stability and optimal performance of closed-loop systems when the fault occurs. The case of incorrect estimation is also considered by comparing the performance index between the switched controller and the passive fault-tolerant controller. The proposed design technique is finally evaluated in the light of a simulation example.     

Position Control of a Flexible Manipulator Using a New Nonlinear Self-Tuning PID Controller

In this paper, a new nonlinear self-tuning PID controller(NSPIDC) is proposed to control the joint position and link deflection of a flexible-link manipulator(FLM) while it is subjected to carry different payloads. Since, payload is a critical parameter of the FLM whose variation greatly influences the controller performance. The proposed controller guarantees stability under change in payload by attenuating the non-modeled higher order dynamics using a new nonlinear autoregressive moving average with exogenous-input(NARMAX) model of the FLM. The parameters of the FLM are identified on-line using recursive least square(RLS) algorithm and using minimum variance control(MVC) laws the control parameters are updated in real-time. This proposed NSPID controller has been implemented in real-time on an experimental set-up. The joint tracking and link deflection performances of the proposed adaptive controller are compared with that of a popular direct adaptive controller(DAC). From the obtained results, it is confirmed that the proposed controller exhibits improved performance over the DAC both in terms of accurate position tracking and quick damping of link deflections when subjected to variable payloads.     

Nonlinear robust control of a small-scale helicopter on a test bench

A nonlinear robust controller design procedure is presented, which is designed to simultaneously satisfy multiple conflicting closed-loop performance specifications. Significantly, a robust performance specification for the experimental system, developed for studying the attitude control of a small-scale helicopter in our previous work, is discussed quantitatively. The robust performance specifications and nominal multiple closed-loop performance specifications are conflicting. Use of the Convex Integrated Design (CID) method can provide, where feasible, a single closed-loop controller which satisfies a set of multiple conflicting performance specifications. However, the resultant controller has a complex form. Here, the standard CID method is extended to a more general control system framework to solve the conflicting simultaneous performance design problem. When compared with the standard CID design, the extended CID design procedure generates a relatively simple closed-loop controller. Finally, the synthesised controller is tested in simulation and is validated with an experimental small-scale test helicopter, demonstrating the performance of the proposed controller.     

Design of a Robust Optimal Decentralized PI Controller Based on Nonlinear Constraint Optimization For Level Regulation: An Experimental Study

This paper presents the development of a new robust optimal decentralized PI controller based on nonlinear optimization for liquid level control in a coupled tank system. The proposed controller maximizes the closed-loop bandwidth for specified gain and phase margins, with constraints on the overshoot ratio to achieve both closed-loop performance and robustness. In the proposed work, a frequency response fitting model reduction technique is initially employed to obtain a first order plus dead time (FOPDT) model of each higher order subsystem. Furthermore, based on the reduced order model, a proposed controller is designed. The stability and performance of the proposed controller are verified by considering multiplicative input and output uncertainties. The performance of the proposed optimal robust decentralized control scheme has been compared with that of a decentralized PI controller. The proposed controller is implemented in real-time on a coupled tank system. From the obtained results, it is shown that the proposed optimal decentralized PI controller exhibits superior control performance to maintain the desired level, for both the nominal as well as the perturbed case as compared to a decentralized PI controller.      

线性自抗扰控制的抗饱和补偿措施

控制输入约束是实际工业过程中普遍存在的现象,然而控制器设计中通常都假设执行机构动态是线性的,因此当执行机构存在约束时,执行机构输出信号与控制器输出信号不一致,使系统的动态性能降低,甚至导致系统不稳定.本文针对线性自抗扰控制(linearactive disturbance rejection control,LADRC)执行机构的约束问题,提出两种抗饱和补偿方案,利用LADRC扩张状态观测器估计控制器状态或者控制器输出与执行器输出的误差,从而使LADRC能快速消除饱和.将这两种方法用到含执行机构饱和的一阶惯性加迟延被控对象进行仿真研究,结果表明两种补偿措施下线性自抗扰控制器能得到较好的控制性能.随后本文将LADRC抗饱和思想推广到负荷频率控制系统(load frequency control,LFC)中,仿真表明基于误差补偿的抗饱和方案对于LFC系统更为有效.     

Performance assessment of control systems in rolling mills – application to strip thickness and flatness control

This contribution takes the control performance monitoring (CPM) technology into a new industrial area, the metal processing, where not much work has been done before. It is shown how to explore not yet discovered opportunities for controller performance improvement in this industrially interesting field, where special aspects have to be considered. This includes online vs. batch-wise performance evaluation, time-based vs. length-based assessment, and oscillation diagnosis. The paper presents two industrial case studies of the performance evaluation of control systems in a tandem cold rolling mill: (1) a feedforward/feedback strip thickness controller; and (2) an internal model control of the strip flatness. Routine operating data are analysed to obtain the performance monitoring metrics in terms of minimum variance index, oscillation index, and to suggest improvement measures. A monitoring tool for calculating and displaying the performance indices has been developed, and tailored to the applications in this field. The results indicate that tuning the feedback thickness controller is suggested to better handle entry thickness disturbances for specific coils. The performance of the flatness controller is found to be satisfactory, thus no actions are needed.     

SECOND ORDER SLIDING MODE CONTROL OF A DIESEL ENGINE

A 2nd order sliding mode algorithm is applied to control the speed of a diesel power generator set. Tuning guidelines are given. The robustness of the controller is investigated and the performance of the 2nd order sliding mode controller is compared with that obtained by a commercial diesel engine controller and a classical proportional‐integral (PI) controller. Robustness to unmodelled dynamics is discussed and implementation results presented.