State feedback controller design of networked control systems

This paper is concerned with the controller design of networked control systems (NCS). A new model of the NCSs is provided under consideration of both the network-induced delay and the data packet dropout in the transmission. In terms of the given model, a controller design method is proposed based on a delay-dependent approach. The feedback gain of a memoryless controller and the maximum allowable value of the network-induced delay can be derived by solving a set of linear matrix inequalities. Two examples are given to show the effectiveness of our method.     

Fault Detection for Nonlinear Networked Control Systems with Markov Data Transmission Pattern

This paper is concerned with the fault-detection problem of nonlinear multiple channels data transmission networked control systems (NCSs). Two irrelevant Markov chains are introduced to describe the data transmission characterization of nonlinear delayed NCSs with data loss in both from sensors to controller and from controller to actuators, and a nonlinear Markovian jump system model is established. Based on this novel model, employing a mode-dependent fault-detection filter as residual generator, a fault-detection filter design of nonlinear NCSs is formulated as a nonlinear H _∞-filtering problem. Then an appropriate Lyapunov functional is chosen to derive the sufficient condition which satisfies the stochastic stability and prescribes the H _∞ attenuation level simultaneously. Especially, the desired mode-dependent fault-detection filters are constructed in terms of certain linear matrix inequalities (LMIs), and explicit parameters are characterized if these LMIs are feasible. The effectiveness of the proposed method is demonstrated by a simulation example.     

Improving Component-Swapping Modularity Using Bidirectional Communication in Networked Control Systems

Availability of low-cost electronics has led to a new breed of control system components, so-called smart components, which can perform control actions in the actuator and sensor components as well as in the controller. ldquoSmartrdquo components can communicate bidirectionally in networked control systems (NCSs). One can improve control system performance and design due to the decentralized, yet more connected, nature of these systems. Current research on NCSs primarily focuses on communication loss and delay. This paper investigates the potential benefits of bidirectional communication in a feedback control loop, which is at the heart of so many applications. First, a definition and quantification of component-swapping modularity is presented. Next, an optimal design formulation is presented for an NCS that maximizes component-swapping modularity. The approach is then demonstrated with an example of driveshaft speed control with a dc motor.     

Robust Disturbance Attenuation with Stabilization for Uncertain Networked Control Systems

This paper investigates the problem of robust stabilization and attenuation for a class of uncertain networked control systems (NCSs) with random communication network-induced delays. Based on the Lyapunov–Razumikhin method, a controller is designed such that both robust stability and a prescribed disturbance attenuation performance for the closed-loop NCS are achieved, irrespective of the uncertainties and network-induced delays. The controller design technique is given in terms of the solvability of bilinear matrix inequalities. An iterative algorithm is proposed to change this non-convex problem into quasi-convex optimization problems, which can be solved effectively using available mathematical tools. The effectiveness of the proposed design methodology is verified by a numerical example.     

Robust \mathcal{H}_{\infty} State Feedback Control of Networked Control Systems with Congestion Control

This paper examines the problem of robust state feedback control of networked control systems with a simple congestion control scheme. This simple congestion control scheme is based on comparing current measurements with last transmitted measurements. If their difference is less than a prescribed percentage of the current measurements then no measurement is transmitted to the controller. The controller always uses the last transmitted measurements to control the system. With this simple congestion control scheme, a robust $\mathcal {H}_{\infty}$ state feedback controller design methodology is developed based on the Lyapunov–Krasovskii functional approach. Sufficient conditions for the existence of delay mode dependent controllers are given in terms of bilinear matrix inequalities (BMIs). These BMIs are converted into quasi-convex linear matrix inequalities (LMIs) and solved by using the cone complementarity linearization algorithm. The effectiveness of the simple congestion control in terms of reducing the network bandwidth is elaborated using simulation examples.     

通讯资源受限网络系统的非均匀采样切换控制

针对含有通道资源受限和量化器的网络控制系统难于控制的问题,提出了基于切换原理的输出反馈控制器设计和动态调度方法.考虑到介质访问约束的影响,利用开关调度矩阵将通信受限的网络化控制系统,转化为含有多个子系统的非均匀采样的切换系统.利用Lyapunov稳定性理论推导出系统鲁棒镇定的充分条件,设计了可以满足任意切换稳定的最优鲁棒控制器和最优动态调度器.最后,通过仿真实例验证了所提出方法的有效性.     

Output feedback nonlinear control for electro-hydraulic systems

In this paper we present an output feedback nonlinear control for position tracking of electro-hydraulic systems (EHSs). Although previous nonlinear control methods improved the position tracking performance of EHS, all of the methods require full state feedback. However, due to cost and space limitations, it is not always possible to measure the full state of the EHS. The proposed method consists of a high gain observer and a passivity-based controller. The high gain observer is designed to estimate the full state, and the passivity-based control is implemented for position tracking. In order to design the passivity-based controller with the high gain observer, a defined Lyapunov condition guarantee that the origin of the tacking error dynamics is exponentially stable by selecting the controller gain. The stability of the closed-loop is studied using the singular perturbation theorem. The performance of the proposed method is validated through simulations and experiments.     

Controller Failure Analysis for Systems with Interval Time-Varying Delay: A Switched Method

This paper studies the problem of controller failure analysis for a class of interval time-varying delay systems with a predesigned state feedback controller. Our objective is to establish conditions concerning controller failure time, under which the systems still keep exponentially stable. For this purpose, the systems with controller failures are first formulated as a class of switched delay systems. Next, based on a piecewise Lyapunov functional method, the exponential stability of such systems is guaranteed by restricting the unavailable rate and failure frequency of the controller. All the results are presented in terms of linear matrix inequalities. Two examples are provided to demonstrate the effectiveness of the proposed technique.     

Design and Stability Criteria of Networked Predictive Control Systems With Random Network Delay in the Feedback Channel

This paper is concerned with the design of networked control systems (NCSs) with random network delay in the feedback channel and gives stability criteria of closed-loop networked predictive control systems. The principle of predictive control is adopted to overcome the effects of network time delay. The necessary and sufficient conditions on the stability of the closed-loop NCS are derived, which provides useful analytical stability criteria. The closed-loop networked predictive control system with bounded random network delay is stable if the corresponding switched system is stable. Simulation and real-time results give an illustration of the proposed control strategies     

基于DBFNN的推设及其在电力系统励磁控制中的应用

本文采用后推设计算法为一类严格反馈系统设计了基于方向基函数神经网络(DBFNN)的自适应控制器.在后推算法中的每步都引入一积分型的Lyapunov函数来设计一个虚拟控制器,并在最后一步为闭环系统综合设计了神经网络控制器.网络权值的调整基于所选择的Lyapunov函数,于是设计方案能保证整个闭环系统是最终一致有界的.把所设计控制方案用于带有未知参数和外部干扰的电力系统励磁控制中.仿真结果表明了所设计控制器的有效性.     

基于线性状态反馈方法的Nadolschi混沌系统同步

研究了一类新型混沌系统——Nadolschi系统的同步控制问题。首先为响应系统设计一个多变量线性状态反馈控制器,进而将Nadolschi系统的同步控制问题转化为误差系统零平衡点的镇定问题。然后,根据Lyapunov稳定性理论,得出使Nadolschi混沌系统达到渐近同步的充分条件。仿真结果验证了所提方法的有效性,所设计的控制器具用结构简单,易于实现等优点。     

基于DBFNN的后推设计及其在电力系统励磁控制中的应用

本文采用后推设计算法为一类严格反馈系统设计了基于方向基函数神经网络(DBFNN)的自适应控制器．在后推算法中的每步都引入一积分型的Lyapunov函数来设计一个虚拟控制器，并在最后一步为闭环系统综合设计了神经网络控制器．网络权值的调整基于所选择的Lyapunov函数，于是设计方案能保证整个闭环系统是最终一致有界的．把所设计控制方案用于带有未知参数和外部干扰的电力系统励磁控制中．仿真结果表明了所设计控制器的有效性．     

High-gain observer-based integral sliding mode tracking control for heavy vehicle electro-hydraulic servo steering systems

The electro-hydraulic servo steering system (EHSSS) is the key element to determine the handling and stability of heavy vehicles. Accurate steering control is challenged due to its complicated structure and a wide range of steering loads. In this paper, an output feedback integral sliding mode control (ISMC) method based on high-gain observer is proposed to solve this issue. First, a new Hurwitz matrix design method is presented for EHSSS with non-chain integrator, in order to prove the convergence of the observer error dynamics. Then, the Lyapunov stability of the observer-based controller is verified. Finally, a test bench is established to experimentally validate the proposed method's effectiveness through multiple test scenarios. The results show the tracking error of the proposed method is significantly smaller than PI and similar to full-state feedback integral sliding mode controller. This paper provides a valuable reference for high-gain observer-based nonlinear control applied to a typical electro-hydraulic servo steering system.     

网络控制系统反馈调度器的设计

本文提出一种基于反馈机理的网络控制系统动态调度器的设计方法.首先利用网络监测器在线获取当前的网络带宽和网络传输误差,预测下一监测器采样周期内可利用的网络带宽.然后利用网络带宽预测值和网络传输误差确定各控制回路采样周期的调节规律,并给出反馈调度器的可调度性约束.当数据包传输发生冲突时,采用MEF(Maximum Error First)作为辅助调度策略,确定数据包的发送优先级.最后通过一组仿真结果验证了所设计的反馈调度器的有效性.     

离散动力系统无退化-配置N个正Lyapunov指数

针对离散时间混沌动力学系统,该文提出一种基于矩阵特征值以及特征向量配置Lyapunov指数为正的新算法。计算离散受控矩阵的特征值以及特征向量,设计一类具有正Lyapunov指数的通用控制器,理论证明系统轨道的有界性和Lyapunov指数的有限性。对线性反馈算子以及微扰反馈算子进行数值仿真分析,验证了算法的正确性、通用性和有效性。性能评估表明,与Chen-Lai算法相比,该方法可以构建较低计算复杂度的混沌系统,并且运行时间较短,其输出序列也具有较强的随机性,实现了无退化、无兼并的离散混沌系统。     

Neural-network-based adaptive control for induction servomotordrive system

A neural-network-based adaptive control (NNAC) design method is proposed to control an induction servomotor. In this NNAC design, a neural network (NN) controller is investigated to mimic a feedback linearization control law; and a compensation controller is designed to compensate for the approximation error between the feedback linearization control law and the NN controller. The interconnection weights of the NN can be online tuned in the sense of the Lyapunov stability theorem; thus, the stability of the control system can be guaranteed. Additionally, in this NNAC system design, an error estimation mechanism is investigated to estimate the bound of approximation error so that the chattering phenomenon of the control effort can be reduced. Simulation and experimental results show that the proposed NNAC servomotor control systems can achieve favorable tracking and robust performance with regard to parameter variations and external load disturbances     

Lyapunov-function-based design of fuzzy logic controllers and itsapplication on combining controllers

This paper presents the design of fuzzy logic controllers (FLCs) for nonlinear systems with guaranteed closed-loop stability and its application on combining controllers. The design is based on heuristic fuzzy rules. Although each rule in the FLC refers to a stable closed-loop subsystem, the overall system stability cannot be guaranteed when all these rules are applied together. In this paper, it is proved that if each subsystem is stable in the sense of Lyapunov (ISL) under a common Lyapunov function, the overall system is also stable ISL. Since no fuzzy plant model is involved, the number of subsystems generated is relatively small, and the common Lyapunov function can be found more easily. To probe further, an application of this design approach to an inverted pendulum system that combines a sliding-mode controller (SMC) and a state feedback controller (SFC) is reported. Each rule in this FLC has an SMC or an SFC in the consequent part. The role of the FLC is to schedule the final control under different antecedents. The stability of the whole system is guaranteed by the proposed design approach. More importantly, the controller thus designed can keep the advantages and remove the disadvantages of the two conventional controllers     

State Feedback $$L_1$$-Gain Control of Positive 2-D Continuous Switched Delayed Systems Via State-Dependent Switching

This paper investigates the stability and \(L_1\)-gain control of two-dimensional (2-D) continuous positive switched delayed systems. Firstly, by constructing an appropriate co-positive Lyapunov–Krasovskii functional, a sufficient condition for asymptotical stability of the system under consideration is derived. Secondly, \(L_1\)-gain performance analysis of the underlying system is investigated. Thirdly, a design methodology for state feedback controller is proposed to ensure that the closed-loop system is asymptotically stable with \(L_1\)-gain performance. Finally, an example is provided to show the effectiveness of the proposed method.     

An Integrated Control and Scheduling Optimization Method of Networked Control Systems

Modern computer and communication network technology has made it convenient to construct networked control systems. Feedback control systems wherein the control loops are closed through a real-time network are called networked control systems (NCSs)[1]. NCSs exhibit the characteristics of high reliability, simple installation, low maintenance, good diagnostic capability, and low cost. Recently, theWhen control and feedback signals transmit through the network, the network delay emerges unavo…     

A Delay Decomposition Approach to Delay-Dependent Robust Passive Control for Takagi–Sugeno Fuzzy Nonlinear Systems

This paper is concerned with the problem of delay-dependent robust passive control for a fuzzy nonlinear system with time-varying delays. A Takagi–Sugeno fuzzy model approach is exploited to design a passive control for nonlinear systems with time-varying delay. By decomposing the delay interval into multiple equidistant subintervals, new Lyapunov–Krasovskii functionals (LKFs) are constructed on these intervals. Employing these new LKFs, a new robust passive control criterion is proposed in terms of linear matrix inequalities, which is dependent on the size of the time delay. We also design a state feedback controller that guarantees a robustly strictly passive closed-loop system for all admissible uncertainties. Finally, two numerical examples are given to illustrate the effectiveness of the developed techniques.