采用一种新型的状态反馈设计方法实现纯滞后系统的控制

本文提出了一种采用最优状态反馈来实现对纯滞后对象的控制的方法。它将纯滞后环节进行非对称二阶伯德近似，然后按照Butterworth滤波器原理设计状态反馈系数矩阵从而实现以纯滞后对象的近似最优控制。仿真实验表明该系统具有较强的鲁棒性和抗扰性能。     

采用状态反馈实现纯滞后系统的控制

本文提出了一种采用最优状态反馈来实现对纯滞后对象的控制方法。它将纯滞后环节进行非对称二阶伯德近似，然后按照Butterworth滤波器原理设计状态反馈系数，从而实现对纯滞后对象的近似最优控制。仿真实验表明该系统具有较强的鲁棒性和抗扰性能。     

基于状态反馈的纯滞后系统的优化设计方法

纯滞后对象是一种很难控制的对象。本文针对纯滞后对象，提出一种串级双环状态反馈控制方式，使这种对象获得较理想的控制品质。系统的设计方法包括：采用数值逼近方法将对象拟合成有理多项式，并选择一种近乎理想的最优低通滤波器作为串级系统内外环的参考模型；根据串级内、外环不同结构分别采用开环和闭环校正，并引入状态观测器，大幅度地减少状态的检测数量；同时采用内外环系统的协调设计，拉开内外环回路的操作频率，有利于提高系统的鲁棒性。本文通过两个工业过程中的纯滞后对象进行仿真实验，证实本文方法相当有效。     

基于PCS7的内模控制器设计与应用

针对工业对象的高阶以及非线性特性,采用二阶加纯滞后模型作为内模控制的内部模型,提出了一种通用内模控制器的设计方法;根据内模控制的原理以及二阶加纯滞后模型的差分方程,推导出通用内模控制器的算法.通过PCS 7 V6.1系统软件中的结构化控制语言SCL将内模控制算法编译成可通用的FB功能块,在西门子过程控制系统PCS7中实现了内模控制;最后利用精度较高的最小二乘法辨识被控对象的模型,将该通用内模控制器应用在工业中普遍使用的高阶大滞后对象换热器的出口温度控制过程中,取得了很好的应用效果;应用表明,内模控制器在工业DCS应用过程中具有高性价比,能有效地拓展内模控制的应用空间.     

纯滞后系统的状态反馈优化设计方法

针对纯滞后对象,提出一种串级双环状态反馈控制方式,使这种对象获得较理想的控制品质。系统的设计方法包括：采用数值逼近方法将对象拟合成有理多项式,并选择一种优化的期望闭环系统,作为串级系统内外环的参考模型;根据串级内、外环不同结构分别采用开环和闭环校正,并引入状态观测器,大幅度地减少状态的检测数量;同时采用内外环系统的协调设计,拉开内外环回路的操作频率,有利于提高系统的鲁棒性。通过工业过程中的纯滞后对象进行仿真实验,证实本方法相当有效,系统动态性能和抗干扰能力明显增强。     

基于继电辨识的Smith预估自校正算法的应用

工业过程控制的对象通常都存在纯滞后环节，含有纯滞后环节的系统特征方程中含有时滞项e^-τS，相当于在回路中引入附加相移，这将引起系统不稳定或降低系统的反馈性能，采用常规PID调节器不能获得较好的控制品质。Smith预估器是克服纯滞后影响的有效方法，但是控制算法需要控制对象的精确数学     

一种含纯滞后对象的模型预测反馈的控制方法

本文提出一种适于对象含大纯滞后的控制算法，其基本思路是在系统的反馈通道上，建立一个与对象相当的参考模型，但不要求该模型与对象模型有特定的关系，利用对象输出与含纯滞后参考模型输出的差异来校正不含纯滞后的该模型输出，以此作为系统的反馈信号实现反馈控制，此法简单，不需复杂的运算，经仿真有比较满意的效果。     

带有输入和状态时滞的高阶非线性前馈系统的自适应控制

本文考虑了一类高阶不确定非线性前馈系统的自适应镇定问题.将高阶非线性进一步放宽到不仅允许状态时滞,而且还具有未知增长率.通过将自适应方法、动态增益控制方法和增加幂次积分器法结合,设计了一个状态反馈控制器.所设计的控制器保证了闭环系统的所有信号有界,平衡点全局稳定,并且原状态收敛到0.     

基于线性状态反馈和高阶泰勒逼近的自抗扰控制方法

针对对象模型不确定性和输入扰动问题, 设计扩张状态观测器. 提出利用高阶泰勒多项式构造综合扰动的内部模型, 将其作为系统的扩张状态, 由Luenberger 状态观测器对其进行估计. 运用线性状态反馈法, 将原系统状态估值反馈至参考输入, 再结合极点配置法和扩张状态估值得到最终的控制作用. 由于将原系统转化为积分串联型, 实现了系统线性化, 并对干扰进行了有效补偿, 使系统抗扰性能大为增强. 通过数例分析验证了所提出方法的有效性.     

状态时滞时变不确定系统的鲁棒H∞ 输出反馈控制器设计

主要研究了存在状态滞后的线性时变不确定时滞系统的鲁棒∞控制分析和综合问题,给出了对所有容许不确定性,被控对象可二次镇定和满足从干扰输入到控制输出的Ｈ∞范数界约束的动态输入出反馈鲁棒Ｈ∞控制分析结果,将不确定时滞系统的鲁棒Ｈ∞输出反馈控制器设问题等价对两个线性时不变系统的状态反馈标准Ｈ∞控制问题,并由此得到反馈阵和观测阵,了终得到鲁棒Ｈ∞控制器综合设计方法。     

Razumikhin‐type approach on state feedback of stochastic high‐order nonlinear systems with time‐varying delay

The Razumikhin‐type approach is introduced to solve the state feedback stabilization problem for a class of stochastic high‐order nonlinear systems with time‐varying delay. Based on the general Razumikhin‐type theorem on stochastic systems established in our paper and backstepping design method, a state feedback controller is constructed to ensure the origin of closed‐loop system is globally asymptotically stable in probability. Our methodology enables us to completely remove the limitations on the derivative of delay, which is the common assumption of stochastic high‐order nonlinear systems with time‐varying delay. The efficiency of the state feedback controller is demonstrated by simulation examples. Copyright © 2017 John Wiley & Sons, Ltd.     

An Efficient Finite Difference Method for The Time‐Delay Optimal Control Problems With Time‐Varying Delay

In this paper, an efficient finite difference method is presented for the solution of time‐delay optimal control problems with time‐varying delay in the state. By using the Pontryagin's maximum principle, the original time‐delay optimal control problem is first transformed into a system of coupled two‐point boundary value problems involving both delay and advance terms. Then the derived system is converted into a system of linear algebraic equations by using a second‐order finite difference formula and a Hermite interpolation polynomial for the first‐order derivatives and delay terms, respectively. The convergence analysis of the proposed approach is provided. The new scheme is also successful for the optimal control of time‐delay systems affected by external persistent disturbances. Numerical examples are included to demonstrate the validity and applicability of the new technique. Some comparative results are included to illustrate the effectiveness of the proposed method.     

Optimal design of fractional order PID controller for time-delay systems: an IWLQR technique

ABSTRACT

In this paper, an optimal design based state feedback gain of fractional order proportional integral derivative (PID) controller for time delay system is proposed. The proposed optimal design is called as IWLQR, which will be the joined execution of both the invasive weed optimization (IWO) and linear quadratic regulator (LQR). The proposed technique modifies a fractional order proportional integral derivative (FOPID) regulator among a high order time delay scheme that achieves an elevated performance for a wide area. In the proposed methodology, the gain of the FOPID controller is tuned to achieve the desired responses which are determined using the LQR theory and the weight matrices of the LQR is anticipated with the assistance of IWO technique. The uniqueness of the projected technique is to reduce the fault in a PID regulator among the higher order time delay scheme by the aid of the increase limits of the regulator. The objective of the proposed control method is chosen in view of the set point parameters and the accomplished parameters from the time delay system. The projected method is employed to achieve the avoidance of high order time delay and the dependability restrictions such as tiny overrun, resolving time and fixed condition defect. This technique is carried out in MATLAB/Simulink platform and the results are separated by the earlier regulator junction representation like Z-N system, Wang technique, curve fitting technique, regression technique which illustrates the superior presentation of the anticipated abstaining in the existing work.     

Adaptive practical preassigned finite‐time stability for a class of pure‐feedback systems with full state constraints

This paper focuses on an adaptive practical preassigned finite‐time control problem for a class of unknown pure‐feedback nonlinear systems with full state constraints. Two new concepts, called preassigned finite‐time function and practical preassigned finite‐time stability, are defined. In order to achieve the main result, the pure‐feedback system is first transformed into an affine strict‐feedback nonlinear system based on the mean value theorem. Then, an adaptive preassigned finite‐time controller is obtained based on a modified barrier Lyapunov function and backstepping technique. Finally, simulation examples are exhibited to demonstrate the effectiveness of the proposed scheme.     

时延不确定离散时间系统的鲁棒跟踪控制

研究一类时延不确定离散时间系统的鲁棒跟踪控制问题．基于线性矩阵不等式(LMI)的控制方法，设计无记忆反馈控制器，构造了适用于时延不确定离散时间系统的Lyapunov函数．通过求解一个LMI便可得到控制器的增益矩阵，从而使系统的状态变量渐近跟踪预先设定的轨迹．仿真示例说明所提出的鲁棒跟踪控制算法是有效的．     

时滞状态反馈控制系统的稳定性增益区域

研究了一阶时滞微分方程的状态反馈P控制、PI控制问题,目的是确定反馈增益的范围使得系统的平衡态是渐近稳定的.对P控制状态反馈控制模型,利用Lambert W函数的主分支给出了确定反馈增益的显式判据以及系统的最优反馈增益;在PI状态反馈控制模型中,运用稳定性切换原理并结合D-划分法确定了在反馈增益平面上系统的稳定性区域,并利用Lambert W函数采用数值方法给出了系统的最优增益曲线.和现有方法相比较,本文方法更直观、计算更简单.     

时滞系统在高速网络下的最优扰动抑制

研究在含有控制时滞与测量时滞的系统在高速通讯网络下最优扰动抑制问题. 首先建立在高速通讯网络下含有控制时滞与测量时滞系统的离散化数学模型, 利用模型转换将时滞系统转化为形式上的无时滞系统. 然后通过求解离散Riccati方程和Stein方程设计含有状态反馈、扰动前馈和控制记忆项的最优控制律, 前馈项和控制记忆项分别补偿了扰动和控制时滞对系统性能的影响. 通过构造降维扰动状态观测器, 设计了含扰动前馈、输出反馈及 控制记忆项的动态控制律, 解决了前馈补偿器的物理不可实现问题. 仿真实例验证了所设计的最优控制律的有效性.     

二阶不稳定时滞过程的二次优化控制及结构整形

针对一类二阶不稳定时滞系统的抗扰动鲁棒性和动态响应问题,提出二次优化控制结构整形的方法来实现其优化控制．首先运用二次优化控制原理,设计系统的无穷维控制器和观测器．然后再用增强局部反馈K_f的结构整形方法,来消除其过渡过程中出现的微振现象．最后通过实例仿真与内模滤波器PID（proportional-integral-derivative）、 改进型Smith两种方案作对比研究,证明了本文方法在跟踪响应以及抗扰动鲁棒性方面的优越性．     

Stabilization of Stochastic Coupled Systems With Time Delay Via Feedback Control Based on Discrete‐Time State Observations

In this paper, the stabilization of stochastic coupled systems (SCSs) with time delay via feedback control based on discrete‐time state observations is investigated. We use the discrete‐time state feedback control to stabilize stochastic coupled systems with time delay. Moreover, by employing Lyapunov method and graph theory, the upper bound of the duration between two consecutive state observations is obtained and some criteria are established to guarantee the stabilization in sense of ‐stability and mean‐square asymptotic stability of SCSs with time delay via feedback control based on discrete‐time state observations. In addition, to verify the theoretical results, stochastic coupled oscillators with time delay are performed. At last, a numerical example is given to illustrate the applicability and effectiveness of our analytical results.     

A sensitivity analysis for control systems having input time delays

The concept of singular sensitivity of a lumped linear system to small pure time delays in controls is introduced. From this, first order changes in a quadratic performance index can be calculated. A design method is proposed which calculates optimal linear feedback laws for the lumped system, but ensures that the effect of control delays is kept “small” in closed loop. Iterative computational algorithms are developed and simple examples presented. For stable plants, the computations always converge, while for unstable plants, the region of convergence limits the allowed delay to “non-dominant” values consistent with stabilisability under the given feedback structure.