基于改进Smith预估控制结构的二自由度PID控制

针对工业过程中的二阶不稳定时滞过程, 基于改进史密斯预估控制结构提出了一种简单的两自由度控制方案.设定值跟踪控制器和扰动抑制控制器采用同一设计程序, 并基于内模控制原理提出了控制器解析设计方案.设定值跟踪控制器和抗扰动控制器可分别通过单性能参数独立调节和优化, 每个控制器都具有PID形式, 给出了控制器调整参数的选择范围和扰动抑制闭环保证鲁棒稳定性的条件.仿真实例验证了提出方法对于近期其他方法的优越性.     

用直接综合法设计的微分先行鲁棒PID控制器

针对积分时滞系统应用直接综合方法设计了一种微分先行鲁棒PID控制器.这种方法基于比较积分时滞系统与后置超前滞后滤波器的微分先行PID控制器组成的闭环系统的特征方程和期望特征方程.期望特征方程由多个位于同一期望位置的极点组成.所设计的控制器的参数以实现期望鲁棒性的方式获得.通过选择不同的调优参数获取相应的Ms值,进而在参...     

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.     

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.     

Internal model control based PID tuning using first-order filter

The selection of filter plays an important role in internal model control (IMC) based controller design. As per the rule, for a minimum-phase delay free plant, IMC based controller is obtained by augmenting a filter. We suggest the use of first-order filter for controller design, which is then parameterized to a conventional PID controller. The proposed scheme brings filter size reduction, closed-loop bandwidth enhancement, and easy formulation of the PID structure. The proposed scheme is applied to some class of linear and nonlinear processes. Further the hardware testing for velocity control of precision modular servo system which contains DC servomotor is carried out through this scheme. Quantitative comparison of servo, regulatory and optimal attributes of the proposed scheme with other popular IMC-PID control techniques depicts sharp reference tracking, good disturbance rejection and minimum integral error performance.     

基于小脑模型关节控制器与PID复合的高速公路交通流密度控制

高速公路交通控制系统是一个复杂的非线性时变系统, 传统的匝道控制方法难以取得满意的控制效果. 为此, 本文提出基于小脑模型关节控制器(CMAC)与PID复合的匝道控制方法. 首先建立了二阶宏观动态交通流模型, 然后研究了CMAC与PID复合控制算法, 结合非线性反馈理论, 设计了基于CMAC与PID复合的高速公路交通流密度控制器, 该密度控制问题是一个输出跟踪和扰动抑制问题, 最后采用两个仿真实例对该方法的有效性进行验证. 结果表明, 复合控制具有优越的密度跟踪性能和抑制噪声干扰的能力; 复合控制方法能够有效地消除交通拥挤, 并使主线车流趋于稳定.     

A unified design for feedback-feedforward control system to improve regulatory control performance

The PID controller is widely used in industries because of its simplicity and robustness. A simple approach to improve regulatory control performance is to combine both feedback PID and feedforward controllers. The feedforward controller enables early compensation of a measured disturbance before it can seriously affect the process. The conventionally derived non-ideal feedforward controllers are not often used in practice. The reason is that an ideal feedforward controller based on direct inversion of process model is often not physically realizable. Several non-ideal feedforward control designs have been proposed where some of them involve rather intensive tuning procedure to obtain good disturbance rejection. In this paper, we present a new systematic method for designing a combined feedback-feedforward control system. The proposed design method is easy to use and applicable to stable, unstable and integrating deadtime processes where the ideal feedforward controller is physically not realizable.     

Optimal control of non-minimum phase integrating processes with time delay using disturbance observer-based control scheme

A systematical design method of optimal control for non-minimum phase integrating processes with time delay using disturbance observer-based (DOB) control scheme is presented. All stabilising controllers and the filter of DOBs for integrating plants are developed. Then the optimal set-point tracking controller and the optimal filter of DOB are systematically derived by minimising the H₂ norm performance specifications. The proposed design method has three main advantages. First, the design procedure is systematical and simple. Specified weight functions are chosen for step inputs and inputs similar to steps. The designed set-point tracking controller and the filter of DOB are given in analytical forms. Second, the designed set-point tracking controller and the filter of the DOB are optimal. They are derived from minimising the performance indexes of set-point tracking and input load disturbance rejection (ILDR). Finally, the set-point tracking performance specification and ILDR specification can be quantitatively achieved by conveniently tuning the adjustable parameters. Numerical simulations are given to illustrate the effectiveness of the proposed method.     

Optimal disturbance rejection controller design for integrating processes with dead time based on algebraic theory

In this paper, an H₂ optimal input-load disturbance rejection (ILDR) controller for integrating processes with dead time is proposed based on the internal model control principle. The main contribution of this work is that the optimal solution under ILDR criterion for integrating processes with dead time and input constant disturbances has been derived based on algebraic theory. To further improve the performance for both set-point tracking and input disturbance rejection, a two-degree-of-freedom (TDOF) control design method has also been developed. Compared with previous advanced control methods, the proposed design method has three main advantages. First, the optimal ILDR controller is derived systematically on the basis of algebraic theory. The designed controller is given in an analytical form. Second, a simple tune principle is developed. The set-point tracking performance specification and robustness stability specification can be quantitatively achieved by monotonously tuning the performance degree in the designed controller. Finally, both optimal set-point tracking performance and input disturbance rejection can be achieved by the proposed TDOF control structure. Numerical simulations are given to illustrate the effectiveness of the proposed method.     

基于优化性能的重复控制器设计

提出一种基于优化性能的重复控制器设计方法.首先,对重复控制器中时滞环节的时延进行修正,以补偿由于低通滤波器的引入所带来的相位滞后,进而提高系统在参考/干扰信号基频处的增益,增强系统对基频信号的跟踪/抑制能力;其次,在重复控制器中加入超前校正环节,不仅拓宽了低通滤波器的带宽,而且提高了系统的高频增益,使得系统在高次谐波处的性能得以大幅提升.重复控制器的参数通过求解2个优化问题得到.在保证系统稳定的前提下,提出的设计方法最大限度地提升了系统的性能.针对光盘驱动器控制系统的仿真结果证实了该设计方法的有效性.     

不稳定时滞对象的串级控制设计

针对常见的开环不稳定串级过程,提出一种新的解析设计方法.副回路中采用两自由度内模控制结构,减少因副回路设定值响应与扰动抑制响应耦合对主回路性能的影响.主回路采用加滤波器的单位反馈控制结构,基于闭环最优灵敏度函数解析推导出设定值响应控制器,保证系统的整体性能.针对副回路存在的乘性不确定性,分析了系统的鲁棒稳定性,最后通过...     

一阶参数不确定滞后过程的鲁棒PID控制器设计

提出一种针对一阶参数不确定滞后过程的鲁棒PI／PID控制器优化设计方法。首先基于D-分割法技术,给出确定一阶参数不确定滞后过程的整个PI／PID控制器的可行鲁棒稳定域算法;在定义一个与控制器给定点跟踪性能、鲁棒性能和抗扰动性能相关的目标函数的基础上,给出PI／PID控制器设计的约束优化问题;最后应用一种启发式粒子群优化（PSO）算法对该约束问题进行求解。仿真结果表明,所提出的方法可得到更小的调节时间、更小的超调、较强鲁棒性和更好的抗扰动性能,表明了所提出的方法的有效性。     

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.     

基于线性自抗扰的开关磁阻电机调速控制研究

开关磁阻电机调速系统是复杂的非线性时变系统,负载扰动大,变量之间耦合严重,针对上述系统的性能特点提出采用线性自抗扰控制策略对系统进行控制的方法。首先为克服负载扰动变化,电机磁链呈非线性以及电流、位置等参数耦合的内外部干扰问题,设计扩张状态观测器对系统内扰和外扰进行准确估计并实时补偿。然后设计PD（比例-微分）控制器抑制系统给定与扩张状态观测器反馈的观测对象状态变量之间的跟踪误差。最后在仿真平台上对设计的控制系统进行试验并与传统PID控制方案进行对比,结果显示,对于给定的阶跃信号线性自抗扰控制器只需0.09s即可达到稳态且无超调,而PID控制器需要3s才能实现稳定跟踪。因此相比于传统PID控制,线性自抗扰控制器拥有更优的动静态性能,并且系统在外部负载扰动和内部模型参数变化的情况下也有良好的控制效果,表现出了很好的鲁棒特性。     

典型工业过程鲁棒PID控制器的整定

提出一阶迟延过程、积分迟延过程、不稳定迟延过程和二阶迟延过程等典型工业过程的鲁棒PID整定公式.本文从抗干扰性能和鲁棒性能两方面综合考虑,把鲁棒PID控制器的设计问题转化为求解一个带鲁棒性能约束的绝对误差积分指标(IAE)优化问题.鉴于该问题是非凸的,本文采用遗传算法来求解,并通过曲线拟合得到典型工业过程的PID控制器的整定公式.仿真结果表明本文的PID整定公式有效,且控制器具有良好的抗干扰能力和频域鲁棒性.     

基于幅值裕度和相位裕度的PID参数最优整定方法

给出一种基于幅值裕度和相位裕度的PID参数最优整定方法.首先,基于改进的D–分割法确定满足幅值裕度和相位裕度要求的控制参数稳定域,然后根据最大灵敏度函数、超调和调节时间定义控制器设计的目标函数,在所得到的控制参数稳定域中计算出一组最优的控制参数值.仿真结果表明,该整定方法能够保证闭环系统具有强鲁棒性、良好的跟踪性能和抗干扰性能.它不仅适用于稳定时滞对象,而且还适用不稳定时滞对象.     

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.     

An improved parallel cascade control structure for processes with time delay

Parallel cascade control strategies, to improve the dynamic performance of a control system, have been proposed earlier mainly for control of stable processes. In this paper, further results are presented for a new parallel cascade control structure and controller design for controlling stable, unstable or integrating processes with time delay. The design of the disturbance rejection controllers and the setpoint filter are based on loop shaping and ISE performance measures, respectively. A modified Smith predictor scheme is used in the primary loop to enhance the closed-loop performance of the system. The stabilization, robustness and performances of time delay processes are analyzed. The disturbance rejection capability of the proposed scheme is superior as compared to some existing methods. Examples are given to illustrate the usefulness of the proposed method and its superiority over some parallel cascade control schemes.     

非自衡时滞对象的改进内模控制

针对化工生产中常见的具有积分和时滞特性的过程对象，采用一种改进的两自由度内模控制方案．其中一个新增的控制器用于设定值跟踪响应的期望极点配置，利用直接合成法设计设定值跟踪控制器；另一个新增的控制器用于稳定对象和抑制扰动，并采用期望闭环余灵敏度法确定控制器．设定值跟踪控制器和扰动抑制控制器可通过性能参数独立调节，并保证系统具有较好的鲁棒稳定性．最后，通过仿真实例验证了控制方案的有效性．     

非平衡负载下轮式移动机器人的抗扰PID控制

在非平衡负载条件下,轮式移动机器人(WMR)的前进、转向速度耦合,影响着轨迹跟踪和避障等运动控制性能.为此,本文提出了一种基于抗扰PID(DR–PID)控制器的WMR速度调节主动抗扰(ADR)控制策略.首先,建立WMR的速度耦合模型,引入解耦矩阵减小静态耦合作用;然后,基于一类改进干扰观测器(DOB)控制方法,设计一种具有ADR能力的PID控制器,即DR–PID,用于WMR的速度分散调节.进一步,考虑高频增益不匹配/不确定性,分析闭环系统稳定性条件.所得结论揭示了PID控制器的抗扰机理;最后,在不平衡负载条件下开展WMR运动控制实验研究,实验结果验证了所提方法的有效性.