连续时间系统的自适应鲁棒控制及应用

本文针对未知SISO系统,采用自适应与鲁棒控制相结合的方法,提出一种按球域切换的自适应鲁棒控制规律,证明了全局稳定性和渐近调节的可实现性.该算法已用于水轮机转速调节,现场实验结果说明了理论的正确性.     

Adaptive Finite‐Time Robust Control of Nonlinear Delay Hamiltonian Systems Via Lyapunov‐Krasovskii Method

This paper investigates the adaptive finite‐time robust control problem of a class of nonlinear time‐delay Hamiltonian systems via the Lyapunov‐Krasovskii (L‐K) method, and proposes some delay‐dependent results on the issue. Different from existing works, this paper first presents a time‐varying finite‐time stability (FTS) criterion via an L‐K functional approach, and obtains two FTS conditions by constructing specific L‐K functionals. Then, the adaptive finite‐time robust control problem is investigated for nonlinear time‐delay port‐controlled Hamiltonian (PCH) systems, and a control design procedure is presented. Finally, the effectiveness of the results is demonstrated by an illustrative example.     

Adaptive Output Feedback based Output Tracking Control for a Time‐Delay System with a PFC

This output tracking control system for time‐delay systems with a parallel feedforward compensator (PFC). It has been clarified that one can design an adaptive output tracking control system for systems with almost strictly positive real (ASPR) properties. However, the robust stability for non‐ASPR time‐delay systems with a PFC introduced for making the resulting augmented system ASPR has not been analyzed. In this paper, it will be clarified that one can design a stable adaptive output tracking control system for time‐delay systems with a PFC, even if the resulting augmented system is not exactly ASPR.     

Adaptive Dual Control of Discrete‐Time Lqg Problems with Unknown‐But‐Bounded Parameter

The dual control for a class of discrete‐time linear‐quadratic Gaussian (LQG) problems is studied in this paper, where there exist unknown‐but‐bounded parameter uncertainties both in the state equation and the observation equation. It is assumed that the unknown parameter belongs to a known bounded interval. To achieve the adaptive dual control, a subdivision for the continuous bounded interval is used, thus, the computational tractability is ensured. Based on such subdivision, the adaptive dual controller developed can learn a more accurate interval that contains the true value of the unknown parameter with a learning error given in advance. The performance of the controller is illustrated with two examples.     

Robust‐decentralized tracking control for a class of uncertain MIMO nonlinear systems with time‐varying delays

A new control design method based on signal compensation is proposed for a class of uncertain multi‐input multi‐output (MIMO) nonlinear systems in block‐triangular form with nonlinear uncertainties, unknown virtual control coefficients, strongly coupled interconnections, time‐varying delays, and external disturbances. By this method, the controller design is performed in a backstepping manner. At each step of backstepping procedure, a nominal virtual controller is first designed to get desired output tracking for the nominal disturbance‐free subsystem, and then a robust virtual compensator is designed to restrain the effect of the uncertainties, delays involved in the subsystem, and the couplings among the subsystems. The designed controller is linear and time‐invariant, so the explosion of complexity in the control law is avoid. It is proved that robust stability and robust practical tracking property of the closed‐loop system can be ensured, and the tracking errors can be made as small as desired. Copyright © 2013 John Wiley & Sons, Ltd.     

关于自适应控制系统的鲁棒稳定性条件

本文用统一的方法对于由自适应控制系统的鲁棒稳定性分析提出的一类时变动态系统的有界解问题给出了一个充分条件。它为鲁棒自适应控制器的设计以及进行相应的理论分析带来了方便。     

一类中立时滞系统的一种改进的鲁棒自适应控制设计

The problem of adaptive robust control is addressed for a class of neutral delay systems. All uncertainties are assumed to be bounded by unknown constants. An improved adaptation law is proposed to estimate the square of these unknown bounds. Then, by making use of the updated values of the squared unknown bounds, an adaptive controller is designed to make the solution of the resultant closed-loop system uniformly ultimately bounded. Furthermore, this method avoids chattering and improves the performance. An example is given to illustrate the effectiveness of this method.     

纯滞后过程控制算法的研究

介绍了工业过程控制中PI控制算法、Smith预估控制算法和采样PI控制算法。给出了采样PI控制算法及控制原理，分析了控制器参数对控制性能的影响，给出了控制器参数选择的方法。并利用：Matlab选取典型一阶纯滞后对象，在控制对象纯滞后时间和增益改变时进行了动态仿真。仿真结果表明，采样PI控制和Smith预估控制具有较强的鲁棒性，而且算法简单、容易实现．所以更适用具有纯滞后的工业过程控制。     

Observer‐Based Adaptive Output Feedback Fault Tolerant Control for Nonlinear Hydro‐Turbine Governing System with State Delay

This paper focuses on the problem of adaptive output feedback fault tolerant control for a nonlinear hydro‐turbine governing system. A dynamic mathematical model of the system is established, which aims to investigate the dynamic performance of the model under servomotor delay and actuator faults. Then, a fault estimation adaptive observer is proposed to achieve online real‐time diagnosis of system faults. Based on the online fault estimation information, an observer‐based adaptive output feedback fault tolerant controller is designed. Furthermore, under reasonable assumptions, the results demonstrate that the closed‐loop control system can achieve global asymptotic stability by Lyapunov function. Finally, the numerical simulation results are presented to indicate the satisfaction control effectiveness of the proposed scheme.     

污水处理过程的自适应控制

把自适应控制方法应用到污水生化处理过程中,主要是对溶解氧浓度的控制。使用双线性模型来简化溶解氧动态,对于一些不可以直接测量得到的重要过程参数,采用递推最小二乘算法来估计得到,并设置一步预测输出为期望的输出,从而得到对溶解氧浓度的最小方差自校正控制方案。仿真结果说明了空气流量和氧气吸收率(OUR)对溶解氧浓度的影响。     

Design and Experimental Evaluation of a Discrete‐time ASPR‐based Adaptive Output Feedback Control System Using FRIT

This paper describes the design of an adaptive output feedback control system in discrete‐time, based on almost strictly positive real (ASPR)‐ness with a feedforward input. It is well‐known that an adaptive output feedback control system based on ASPR conditions can achieve asymptotic stability via a constant feedback gain. Unfortunately, most realistic systems are not ASPR because of the severe conditions. The introduction of a parallel feedforward compensator (PFC) is an efficient way to alleviate such restrictions. However, the problem remains that there exists a steady state error between the output of the augmented system and the output of the original system. The proposed scheme provides a strategy wherein the feedforward input is utilized such that the steady state error is removed. Furthermore, the fictitious reference iterative tuning (FRIT) approach is employed to determine the control parameters using one‐shot input/output experimental data directly, without prior information about the control system. This paper explains how the FRIT approach is applied in designing an adaptive output feedback control system. The effectiveness of the proposed scheme is confirmed experimentally, by using a motor application.     

城市污水处理过程自适应滑模控制

针对城市污水处理过程时滞导致难以稳定控制的问题, 提出一种自适应滑模控制方法(Adaptive sliding mode control, ASMC). 首先, 分析推流时滞对城市污水处理生化反应过程的影响, 建立时滞影响下的城市污水处理运行控制模型; 其次, 设计一种基于模糊神经网络的预估补偿模型, 完成滞后变量的准确预测, 实现控制模型中变量时刻的统一; 最后, 设计一种具有自适应开关增益系数的滑模控制器(Sliding mode control, SMC), 实现溶解氧和硝态氮的稳定控制. 将提出的自适应滑模控制方法应用于城市污水处理过程基准仿真平台, 实验结果显示该方法能够实现城市污水处理运行过程稳定控制.     

大纯滞后系统的自适应补偿控制

针对工业过程中普遍存在的纯滞后对象的控制问题,提出了一种带误差补偿环节的模型参考自适应控制方法。仿真结果表明,这种自适应控制器对于一类大纯滞后系统的控制具有比较好的控制效果,且结构简单,有一定的鲁棒性。     

时滞过程的多变量广义预测控制算法

文章提出了用广义预测控制算法解决多变量系统的时滞问题的一种新的方案。该方法将时间滞后因子自然纳入系统的控制机制,可完全无误差的实现对时滞系统的控制,克服了传统近似法解决时滞所带来的误差问题。这种广义预测控制算法能有效的控制开环不稳定非最小相位系统,并有良好的解耦性能．在跟踪性．鲁棒性和抗下扰性方面都得到了很好的控制效果。     

Robust Finite‐Time Control for Linear Time‐Varying Delay Systems With Bounded Control

This paper develops a novel finite‐time control design for linear systems subject to time‐varying delay and bounded control. Based on the Lyapunov‐like functional method and using a result on bounding estimation of integral inequality, we provide some sufficient conditions for designing state feedback controllers that guarantee the robust finite‐time stabilization with guaranteed cost control. The conditions are obtained in terms of linear matrix inequalities (LMIs), which can be determined by utilizing the MATLAB LMI Control Toolbox. A numerical example is given to show the effectiveness of the proposed method.     

Multi‐Variable Direct Self‐Organizing Fuzzy Neural Network Control for Wastewater Treatment Process

A multi‐variable direct self‐organizing fuzzy neural network control (M‐DSNNC) method is proposed for the multi‐variable control of the wastewater treatment process (WWTP). In this paper, the proposed control system is an essential multi‐variable control method for the WWTP. No exact plant model is required, which avoids the difficulty of establishing the mathematics model of WWTP. The M‐DSNNC system is comprised of a fuzzy neural network controller and a compensation controller. The fuzzy neural network is used for approximating the ideal control law under a general nonlinear system. Moreover, the neural network is designed in a self‐organizing mode to adapt the uncertainty environment. Simulation results, based on the international benchmark simulation model No.1 (BSM1), demonstrate that the control accuracy is improved under the proposed M‐DSNNC method, and the controller has a much stronger decoupling ability.     

电厂污水处理的自适应控制

污水处理的 PH值控制经常面对大滞后系统 ,且系统的过程特性随污水流量和原水 p H值等因素而变化 ,难以控制。本文提出的自适应前馈和自适应反馈控制技术可将污水 p H值平稳控制在设定值± 0 .15的范围内 ,采用普通 PL C实现。     

Adaptive Pseudo Inverse Control for a Class of Nonlinear Asymmetric and Saturated Nonlinear Hysteretic Systems

This paper aims at eliminating the asymmetric and saturated hysteresis nonlinearities by designing hysteresis pseudo inverse compensator and robust adaptive dynamic surface control(DSC)scheme.The"pseudo inverse"means that an on-line calculation mechanism of approximate control signal is developed by applying a searching method to the designed temporary control signal where the true control signal is included.The main contributions are summarized as:1)to our best knowledge,it is the first time to compensate the asymmetric and saturated hysteresis by using hysteresis pseudo inverse compensator because the construction of the true saturated-type hysteresis inverse model is very difficult;2)by designing the saturated-type hysteresis pseudo inverse compensator,the construction of true explicit hysteresis inverse and the identifications of its corresponding unknown parameters are not required when dealing with the saturated-type hysteresis;3)by combining DSC technique with the tracking error transformed function,the"explosion of complexity"problem in backstepping method is overcome and the prespecified tracking performance is achieved.Analysis of stability and experimental results on the hardware-inloop platform illustrate the effectiveness of the proposed adaptive pseudo inverse control scheme.     

Robust H∞ Control for Non‐Minimum Phase Switched Cascade Systems with Time Delay

The H_∞ control of a class of the uncertain switched nonlinear cascaded systems with time delay is explored in this paper via the multiple Lyapunov functions. The considered systems are assumed to comprise an inherently nonlinear and a linearizable nonlinear dynamic system that may be non‐minimum phase. A group of partial differential inequalities containing adjustable functions are used in the control design task. The state feedback controllers and a suitable switching law are designed simultaneously so as to achieve the desired disturbance attenuation while preserving asymptotic stability for all admissible uncertainties. The partial differential inequalities are of lower dimension than general Hamilton–Jacobi inequalities, and therefore the solving process is feasible. This particular technique is applicable even if no subsystem is asymptotically stable. The non‐minimum phase property is compensated for by means of an appropriate switching mechanism. A robust H_∞ control for non‐switched cascade system with time delay is obtained in addition. An illustrative example is given to demonstrate the efficiency of the proposed design method.     

Robust Adaptive Fractional‐Order Terminal Sliding Mode Control for Lower‐Limb Exoskeleton

This paper introduces a robust adaptive fractional‐order non‐singular fast terminal sliding mode control (RFO‐TSM) for a lower‐limb exoskeleton system subject to unknown external disturbances and uncertainties. The referred RFO‐TSM is developed in consideration of the advantages of fractional‐order and non‐singular fast terminal sliding mode control (FONTSM): fractional‐order is used to obtain good tracking performance, while the non‐singular fast TSM is employed to achieve fast finite‐time convergence, non‐singularity and reducing chattering phenomenon in control input. In particular, an adaptive scheme is formulated with FONTSM to deal with uncertain dynamics of exoskeleton under unknown external disturbances, which makes the system robust. Moreover, an asymptotical stability analysis of the closed‐loop system is validated by Lyapunov proposition, which guarantees the sliding condition. Lastly, the efficacy of the proposed method is verified through numerical simulations in comparison with advanced and classical methods.