不稳定对象的PID控制

对于不稳定对象的控制，常规的稳定裕度和性能指标已不适用，为此讨论了控制不稳定对象时的下幅值裕度和相位裕度的取值范围,给出了灵敏度函数，并讨论了用H∞设计时性能权函数的选择问题。     

时滞对象PID控制器的参数稳定域求解方法

研究时滞对象的PID控制器的参数稳定域的求解方法,通过引入Rekasius变换简化时滞特征多项式,并得到稳定域边界上PID控制器的3个参数所满足的方程.通过引入正弦变换,将对控制器参数在无穷范围内的遍历转为有限范围内的遍历,而特征多项式中的已知时滞被用以检验所遍历的点是否在稳定域边界上,在得到所有可能的稳定域边界后,使用Nyquist稳定性判据确定实际的稳定域.该方法适用于任意形式的单时滞对象,为实际应用中PID控制器的参数整定提供理论依据.     

对象不稳定的内模控制系统的参数优化仿真

内模控制系统的参数优化对提高工业生产效率意义重大.内模控制系统的产生随控制对象的状态变化而发生变化,随着控制过程复杂程度的增加,控制对象的不稳定状态极具增加,控制参数发生不可控突变.传统的参数控制方法采用补偿技术控制参数突变,但是,这种补偿存在较为明显的滞后性,属于后发式控制,容易形成过控制和欠控制等弊端.为解决上述问题,提出一种控制器和稳定器的参数化设计方法,针对对象不稳定的改进内模控制系统,利用基于传递函数互质分解的频域理论,在保证内稳定性及鲁棒无差跟踪一般性结论的基础上,推导得到所有满足条件的控制器和稳定器的参数化表达式,在众多满足一般性结论的控制器集合中找寻最优控制器,进一步实现系统跟踪性能,抗扰性及鲁棒性能上的优化,最后通过Matlab/Simulink仿真平台进行仿真,验证了所得结论的真实性和可靠性.提出的参数化优化方法可进一步应用于其它内模控制系统的扩展中,优化了参数控制过程.     

滞后不确定系统的鲁棒稳定调节器设计

本文对于满足匹配条件的滞后不确定线性系统,鲁里叶问题的非线性系统,基于李亚普诺夫稳定性定理,推导出状态反馈系统鲁棒稳定的充分条件.通过建立规范的黎卡提代数方程,给出一种简洁的鲁棒稳定状态调节器的设计方法.     

高阶时滞过程预测PID控制器设计及鲁棒稳定性分析

针对高阶加滞后对象稳定性分析的局限性,提出了预测PID控制器的设计方法,利用Kharitonov定理和边缘理论分析此系统在参数不确定情况下输入、输出的鲁棒稳定性,并给出了系统保持稳定的最大过程参数区间。仿真结果表明,当过程参数偏离标称值时,此类预测PID控制器的设计方法能够使系统保持很好的控制性能和鲁棒稳定性能。是一种值得在实际工程中推广应用的新型控制器。     

复杂高阶对象的预测PID控制

针对复杂高阶对象提出了一种基于数值最优模型降阶方法,并基于这种降阶模型设计了预测PID控制器,将此控制器应用于原始模型能够得到很好地控制效果。数值最优模型降阶算法使高阶对象能近似为一阶加时滞对象或二阶加时滞对象,通过模型阶跃响应和Bode图对比,降阶模型曲线很好地逼近原始模型曲线。预测PID对大时滞对象有着很好地控制效果,模型降阶使得预测PID很好地控制复杂高阶对象,且其结构简单,可调参数少的特点。     

具有时滞的积分和不稳定对象的鲁棒控制

针对含时滞的积分和不稳定对象提出了一种新颖的两自由度控制结构,首先用一个比例控制器镇定给定值响应,然后基于鲁棒H₂最优性能指标设计给定值跟踪控制器.根据实际运行抗干扰要求,在对象输入和输出端之间设计负载扰动抑制闭环,利用扰动观测器抑制负载干扰信号,通过提出期望的闭环余灵敏度函数来确定扰动观测器,同时给出了扰动抑制闭环保证鲁棒稳定性的充要条件.最后通过仿真实例验证了该方法相对于近期其它方法的优越性.     

不稳定一阶加时滞系统的两自由度控制

针对一阶加时滞不稳定系统提出两自由度控制改进方案,该方案的控制结构由两个控制器组成,分别作用于设定值追踪和抑制负载干扰,并且设定值追踪响应与负载干扰响应完全解耦.采用直接综合法对控制器进行参数整定,并根据最大灵敏度函数、设定值追踪响应以及负载干扰响应来选择参数λd和λs.仿真例子证明了所提结构在系统性能和鲁棒稳定性方面...     

一阶滞后对象的温度控制

本文主要介绍了利用μ XL中小型集散控制系统,对未知参数的一阶惯性滞后对象,实现温度控制,并得到理想的温度控制曲线。     

Improved PID controller design for unstable time delay processes based on direct synthesis method and maximum sensitivity

In this paper, a proportional-integral-derivative controller in series with a lead-lag filter is designed for control of the open-loop unstable processes with time delay based on direct synthesis method. Study of the performance of the designed controllers has been carried out on various unstable processes. Set-point weighting is considered to reduce the undesirable overshoot. The proposed scheme consists of only one tuning parameter, and systematic guidelines are provided for selection of the tuning parameter based on the peak value of the sensitivity function (M_s). Robustness analysis has been carried out based on sensitivity and complementary sensitivity functions. Nominal and robust control performances are achieved with the proposed method and improved closed-loop performances are obtained when compared to the recently reported methods in the literature.     

一类非自衡加纯滞后系统的双预测P I 控制

提出了一类基于非自衡加大纯滞后过程的双预测PI控制器的结构形式，这种控制器结构筒单，可调参数少，参数的调节方便、直观，仿真结果表明：在干扰和模型失配的情况下，此类控制器仍具有良好的控制性能和鲁棒稳定性，是一种值得在实际工程中推广应用的新型控制器。     

Synthesis of PID controllers for integral processes with time delay

This article deals with the problem of determination of the stabilizing parameter sets of Proportional‐Integral‐Derivative (PID) controllers for first‐order and second‐order integral processes with time‐delay. First, the admissible stabilizing range of proportional‐gain is determined analytically in terms of a version of the Hermite–Biehler Theorem applicable to quasi‐polynomials. Then, based on a graphical stability condition developed in parameter space, the complete stabilizing regions in an integral‐derivative plane are drawn and identified graphically, not calculated mathematically, by sweeping over the admissible range of proportional‐gain. An actual algorithm for finding the stabilizing parameter sets of PID controllers is also proposed. Simulations show that the stabilizing regions in integral‐derivative space are either triangles or quadrilaterals. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

积分加纯滞后系统的双预测PI控制及其应用

Smith预估控制器控制积分加大纯滞后过程时,鲁棒稳定性差,输出存在静态余差,无实际应用价值.提出了一类基于该过程的双预测PI控制器:具有内环和外环两种预测PI控制器.内环将系统稳定,外环消除输入干扰的影响和改善控制系统的动态性能.这种控制器结构简单,可调参数少,参数的调节方便、直观.仿真和实际应用表明:在干扰和模型失配的情况下,此类控制器仍然具有良好的控制性能和鲁棒稳定性能,是一种值得在实际工程中推广应用的新型控制器.     

时滞过程改进型Smith预估器的整定

证明Majhi和Atherton(1999)文所提出的改进型Smith预估器等价于一改进的内模控制结构 (IMC), 并对该结构提出一种三阶段设计方法. 为获得扰动抑制和稳定鲁棒性的均衡, 采用了鲁棒控制方法来整定反馈环控制器. 针对某些典型的积分和不稳定时滞过程的设计表明所提方法能获得较好的扰动抑制和稳定鲁棒性的均衡.     

一类非自衡过程预测PID控制器的设计及鲁棒稳定性的分析研究*

针对一类非自衡过程,为了提高系统的整体性能,提出了预测PID控制器的设计方法;利用Kharitonov 定理和边缘理论分析此系统在参数不确定情况下输入、输出的鲁棒稳定性,并给出了系统保持稳定的最大过程参数区间。仿真结果表明,当过程参数偏离标称值时,此预测PID控制器的设计方法能够使系统保持很好的鲁棒稳定性,是一种值得在实际工程中推广应用的新型控制器。     

Enhanced design of cascade control systems for unstable processes with time delay

In this paper, optimal H₂ internal model controller (IMC) is designed for control of unstable cascade processes with time delays. The proposed control structure consists of two controllers in which inner loop controller (secondary controller) is designed using IMC principles. The primary controller (master controller) is designed as a proportional-integral-derivative (PID) in series with a lead-lag filter based on IMC scheme using optimal H₂ minimisation. Selection of tuning parameter is important in any IMC based design and in the present work, maximum sensitivity is used for systematic selection of the primary loop tuning parameter. Simulation studies have been carried out on various unstable cascade processes. The present method provides significant improvement when compared to the recently reported methods in the literature particularly for disturbance rejection. The present method also provides robust closed loop performances for large uncertainties in the process parameters. Quantitative comparison has been carried out by considering integral of absolute error (IAE) and total variation (TV) as performance indices.     

Fuzzy predictive PI control for processes with large time delays

This paper presents the design, tuning and performance analysis of a new predictive fuzzy controller structure for higher order plants with large time delays. The designed controller consists of a fuzzy proportional-integral (PI) part and a fuzzy predictor. The fuzzy predictive PI controller combines the advantages of fuzzy control while maintaining the simplicity and robustness of a conventional PI controller. The dynamics of the prediction term are adaptive to the system's time delay. The prediction term has two parts: a fuzzy predictor that uses the system time delay as an input for calculating the prediction horizon and an exponential term that uses the prediction horizon as its positive power. The prediction term also introduces phase lead into the system which compensates for the phase lag due to the time delay in the plant, thereby stabilizing the closed-loop configuration. The performance of the proposed controller is compared with the responses of the conventional predictive PI controller, showing many advantages of the new design over its conventional counterpart.     

积分时滞过程的数字P I D 控制

对积分时滞过程提出一种数字PID控制结构，通过一个内部反馈回路对积分时滞过程进行预稳定控制，并给出数字PI控制器的设计算法，仿真结果显示该控制结构具有良好的设定值跟踪特性，并且对时滞偏差具有很强的鲁棒性能，最后简要讨论了抗负载干扰的控制结构。