广义预测控制的直接算法

采用三个辨识器分别辨识开环系统、闭环系统和控制器的参数,利用开环系统参数计算预测输出和参考轨迹,通过辨识闭环系统参数得到广义输出,用于辨识控制器的参数,并给出一种广义预测控制的直接算法。仿真结果表明该算法是有效可行的。     

闭环辨识与开环辨识的比较及应用

用数字仿真的方法,在同一个单输入单输出线性离散随机系统中,把四种不同实验条件下的闭环辨识与开环辨识进行比较。结果表明,在调节器输出端施加伪随机二位信号的实验条件,适宜于工业生产过程应用的闭环辨识实验条件。按此实验条件进行闭环辨识可以得到精度与开环辨识相近的过程模型。也在实验室规模的热交换器上进行了闭环和开环辨识,得到了与数字仿真一致的结果。     

一种闭环条件下的多变量系统辨识方法

为得到带有色噪声的闭环多变量系统参数无偏估计,提出两阶段随机梯度辨识算法,此算法利用中间模型将闭环问题转化成两个开环问题,并基于随机梯度算法和递阶辨识原则,用最速下降法极小化预测误差准则来得到参数估计.算法只需一个测试信号,不需要控制器的先验知识,计算简便,能获得满意的结果,适用于闭环多变量系统的在线辨识.     

基于二自由度PI的微型涡喷发动机转速闭环控制

针对传统PI控制无法使微型涡喷发动机的扰动抑制性能与设定值跟踪性能同时最佳的问题,开展了微型涡喷发动机二自由度（Two-Degree-of-Freedom,2-DOF）PI控制研究。首先基于Speedgoat实时目标机搭建了快速原型试验系统。根据发动机开环试验数据辨识得到不同稳态点下的传递函数模型,在此基础上设计了2-DOF PI控制器,并进行仿真验证。最后将控制算法部署至Speedgoat中开展实物试验。结果表明,设计的2-DOF PI控制器能够使微型涡喷发动机的扰动抑制性能与设定值跟踪性能同时最佳,并在发动机较大的工作范围内有良好的控制性能。     

基于闭环降阶模型的pH中和过程自适应控制

针对pH中和过程,提出了基于闭环系统降阶模型的自适应PI控制器.首先利用三阶模型直接辨识高阶闭环系统,然后从闭环系统模型中提取反映闭环系统动态性能的特征量,并利用特征量建立相应的规则来整定控制器.该方法解决了传统自适应控制中难以获取精确对象模型的问题.仿真结果表明,所设计的方法实现了对pH中和过程的有效控制.     

含复杂回路控制系统奈氏稳定判据的讨论及应用

奈奎斯特频域稳定判据是判别控制系统稳定性的常用方法。它的特点是根据开环系统频率特性曲线判定闭环系统的稳定性。含复杂回路的控制系统用不同的等效化简方法会得到不同的开环传递函数。通过讨论,证明同一系统不同开环传递函数应用奈奎斯特频域稳定判据得到的闭环稳定性的结果是相同的。因此在实际工程中,可以灵活地根据系统等效化简的原则得到其开环传递函数。应用上述结论对含间隙的机电伺服系统进行了等效化简,并对其闭环稳定性进行分析,同时分析刚度、阻尼、转动惯量对系统稳定性的影响。     

膀胱肿瘤恒温热灌注治疗模拟设备的控制实验研究

众所周知,对实际被控对象的模型辨识是进行良好控制的重要前提。本论文研究了一种开环辨识方法。被辨识的对象是膀胱恒温热灌注治疗仪模拟设备,对该对象进行了开环飞升曲线测试,根据记录的输出曲线,采用改进的面积法对被控过程的一阶惯性加时滞模型进行参数估计,得到被控对象的传递函数。然后,根据所得到的过程模型,进行PID参数整定并进行了闭环的控制试验。实验表明,此方法具有较好的辨识精度,对测量噪声不敏感,闭环控制实验也表明了该控制系统的可行性。     

过程信息约束的前向通道优化辨识及多目标整定方法

闭环回路中输出噪声通过反馈与输入强相关,造成闭环系统的辨识难,甚至不可辨识的问题,并且在控制器参数的优化过程中,往往只强调性能指标或质量指标之一。为此,对于闭环稳定且可辨识系统,采用前向通道模型隔离输出噪声对输入的干扰,模拟闭环过程对象的动态特性,利用已知的闭环稳定PI/PID控制器参数和闭环系统输入输出数据,提取闭环过程信息,并用于确定前向通道模型参数优化的约束条件,充分结合PSO算法的全局寻优能力和SQP的局部搜索能力,优化辨识获得对象的前向通道模型。在此基础上利用NSGA-Ⅱ进行前向通道的基于质量指标和性能指标的多目标整定,采用相似度从优化得到的等效解中获得权衡最优解,最后将权衡最优解用于真实过程验证其优化的有效性。通过仿真研究,证明了该方法的有效性和合理性。     

一类分数阶系统的分析及控制器设计

针对一类与传统一阶惯性环节传递函数结构类似的分数阶系统,推导出该类分数阶系统稳定的参数取值范围,并给出了不同时间响应与分数阶阶次的对应关系.然后基于该类分数阶系统同时设计了分数阶PIλ控制器和整数阶PI控制器,控制器参数采用粒子群优化算法得到.结果表明:在控制该类对象时两者均能取得很好的控制效果,证明了本文所提方法的有效性.但由于整数阶PI控制器比分数阶PIλ控制器简单且便于实现,因此在工程应用中针对该类分数阶对象选择PI控制器即可满足要求.     

连续搅拌反应釜过程的闭环增益成形PID控制器设计

针对连续搅拌反应釜（CSTR）系统控制问题,设计了一种基于闭环增益成形算法的PID控制器,以提高PID控制器设计的简洁性和鲁棒性。首先假设期望闭环回路传递函数有一阶形式,同时将受控对象的一阶传递函数和PID控制器构成实际闭环回路传递函数。然后,比较期望闭环回路传递函数和实际闭环回路传递函数,即可确定PID参数。最后,以某CSTR系统为例,利用该方法设计了PID控制器,并通过仿真结果比较,检验了该方法所得PID控制器的良好鲁棒稳定性和动态品质。     

A new class of nonlinear PID controllers with robotic applications

This paper introduces a new class of simple nonlinear PID controllers and provides a formal treatment of their stability analysis. These controllers are comprised of a sector-bounded nonlinear gain in cascade with a linear fixed-gain P, PD, PI, or PID controller. Three simple nonlinear gains are proposed: the sigmoidal function, the hyperbolic function, and the piecewise–linear function. The systems to be controlled are assumed to be modeled or approximated by second-order transfer functions, which can represent many robotic applications. The stability of the closed-loop systems incorporating nonlinear P, PD, PI, and PID controllers are investigated using the Popov stability criterion. It is shown that for P and PD controllers, the nonlinear gain is unbounded for closed-loop stability. For PI and PID controllers, simple expressions are derived that relate the controller gains and system parameters to the maximum allowable nonlinear gain for stability. A numerical example is given for illustration. The stability of partially-nonlinear PID controllers is also discussed. Finally, the nonlinear PI controller is implemented as a force controller on a robotic arm and experimental results are presented. These results demonstrate the superior performance of the nonlinear PI controller relative to a fixed-gain PI controller. © 1998 John Wiley & Sons, Inc. 15: 161–181, 1998     

基于参数辨识的自适应解耦控制算法的研究

多变量模型的复杂结构、强耦合性、被控对象参数的未知、慢时变等问题要求控制器必须具有良好的自适应性,针对以上问题提出了一种基于改进的广义最小方差闭环自适应解耦控制器实现更好的自适应,其由参数可调的控制器和自适应控制律组成,此控制器通过将闭环系统方程的传递函数矩阵等于期望的对角矩阵来实现解耦,同时改进的辨识算法可进行在线辨识控制器的参数实现同步自适应解耦。通过以CARMA为多变量控制模型,采用该方法进行仿真有效的解决了多变量之间的耦合性。结果表明该方法能够适应相应的变化,跟踪性能较好,且具备良好的解耦能力,进而保证了闭环系统的稳定性,从而验证了此方法能够效提高控制系统的稳定性和鲁棒性。     

Normalized decoupling control for high-dimensional MIMO processes for application in room temperature control HVAC systems

A novel decoupling control system design for high-dimensional multi-input, multi-output (MIMO) processes is presented. Based on the Relative Normalized Gain Array (RNGA), an Equivalent Transfer Function (ETF) for each element in the transfer function matrix was derived for the closed-loop control system and was used to approximate the inverse of the process transfer function matrix. The decoupler could be easily determined with each element in the First-Order-plus-Time-Delay (FOPTD) form and resulted in a stable, proper and causal decoupled matrix. A PI/PID controller could then be designed to meet the performance objectives. The main advantage of this method was its simplicity; it did not require extensive calculation effort. To demonstrate its effectiveness, the decoupling control strategy was applied to control the temperatures of four neighboring rooms in an HVAC process.     

PI-PD控制器的应用研究

自动控制系统的前向通道采用PI控制,而反馈环内加入PD控制,由此构成了PIPD控制器。PI—PD控制器不仅具有与PID控制相似的功能,并且对于含有积分、振荡或不稳定环节的控制对象,可以实现较好的闭环控制。本文介绍了PI—PD控制器的结构和参数计算方法,将该控制器应用于一个随动系统中,通过仿真分析,表明了PI—PD控制器的特点和优越性。     

Constructing modal control systems for plants with meromorphic transfer function

A problem of constructing an infinite-dimensional controller that ensures the given desired distribution of poles and a part of zeros of the transfer function of the closed-loop system is solved for the plant with distributed parameters. Transfer functions of the plant, controller and closed-loop system are considered in the class of meromorphic functions. The modal controller is synthesized directly based on the desired transfer function of the closed-loop system. The method of synthesizing the controller is reduced to searching an interpolation series. An example is given.     

Finite-dimensional control of linear parabolic systems with unbounded output operators

In this paper, we studyH control of linear parabolic systems with unbounded output operators. Our aim is to construct a finite-dimensional stabilizing controller for the linear parabolic system that makes the H norm of the closed-loop transfer function less than a given positive number delta. To this end, we first derive a finite-dimensional reduced-order system for the linear parabolic system. Then, for the reduced-order model, we construct a stabilizing controller that makes theH norm of the closed-loop transfer function less than another positive number. It is proved that the finitedimensional controller together with a residual mode filter plays a role of a finite-dimensional stabilizing controller that makes theH norm of the closed-loop transfer function less than delta for the original linear parabolic system, if the order of residual mode filter is chosen sufficiently large.     

基于H∞理论的关联大系统分散鲁棒控制

基于H∞理论提出了关联大系统分散鲁棒控制的一种新的设计方法.得到的控制器不但 使闭环系统渐近稳定,而且能使闭环系统从扰动输入到被控输出的传递矩阵的H∞范数小于 某个给定的扰动变小常数,并对系统参数的不确定性具有鲁棒性.     

基于Riccati方程和LMI算法的H∞控制器的设计与实现

H∞控制是一种重要的鲁棒控制方法,它以H∞范数作为控制性能指标,是一种最优控制方法,目的是求出系统内部稳定的控制器,使闭环传递函数的无穷范数极小,达到控制的目的。以固高公司的直线一级倒立摆为控制对象,实现基于Riccati方程和LMI算法的H∞控制器设计,采用M文件及simulink实现系统建模、控制器的设计,完成系统算法的验证,实验表明,控制器的输出、倒立摆系统的状态变量变化平稳,系统具有较强的鲁棒性,系统表现出良好的动态品质,验证了H∞控制器的有效性。     

H∞ and positive-real control for linear neutraldelay systems

This note is concerned with the H_∞ and positive-real control problems for linear neutral delay systems. The purpose of H_∞ control is the design of a memoryless state feedback controller which stabilizes the neutral delay system and reduces the H_∞ norm of the closed-loop transfer function from the disturbance to the controlled output to a prescribed level, while the purpose of positive-real control is to design a memoryless state feedback controller such that the resulting closed-loop system is stable and the closed-loop transfer function is extended strictly positive real. Sufficient conditions for the existence of the desired controllers are given in terms of a linear matrix inequality (LMI). When this LMI is feasible, the expected memoryless state feedback controllers can be easily constructed via convex optimization     

Model-reference robust tuning of 2DoF PI controllers for first- and second-order plus dead-time controlled processes

The aim of this paper is to present a robust tuning method for two-degree-of-freedom (2DoF) proportional integral (PI) controllers. This is based on the use of a model reference optimization procedure with servo and regulatory target closed-loop transfer functions for first- and second-order plus dead-time (FOPDT, SOPDT) controlled process models. The designer is allowed to deal with the performance/robustness trade-off of the closed-loop control system by specifying the desired robustness level by selecting a maximum sensitivity in the range from 1.4 to 2.0. In addition, a smooth servo/regulatory performance combination is obtained by forcing both closed-loop transfer functions to perform as closely as possible to non-oscillatory dynamic targets. A unified set of controller tuning equations is provided for FOPDT and SOPDT models with normalized dead-times from 0.1 to 2.0 that guarantees the achievement of the design robustness level. The robustness of the control system is analyzed as well as the robustness–fragility and performance–fragility of the optimized controllers. Comparative examples show the effectiveness of the proposed tuning method. The exact achievement of the control system robustness target for all the controlled process models considered (first- and second-order) is one of the distinctive characteristics of the proposed model reference robust tuning (MoReRT) method.