OPEN‐LOOP AND CLOSED‐LOOP OPTIMIZATION OF LINEAR CONTROL SYSTEMS

A canonical optimal control problem for linear systems with time‐varying coefficients is considered in the class of discrete controls. On the basis of linear programming methods, two primal and two dual methods of constructing optimal open‐loop controls are proposed. A method of synthesis of optimal feedback control is described. Results are illustrated by a fourth‐order problem; estimates of efficiency of proposed methods are given.     

基于线性二次型的单神经元PID最优控制器设计及仿真

讨论了线性二次型最优控制理论在神经网络PID控制系统中的应用.将二次型性能指标引入单神经元PID控制器中,设计出单神经元自适应PID最优控制器,从而实现了PID参数在线自适应寻优.给出了完整的设计过程和学习算法,分析了其稳定性.最后,运用MATLAB仿真实现证明了该方法的可行性、有效性,并得到了较为理想的控制效果.     

一个新超混沌系统及其线性反馈控制

为提高混沌吸引子的拓扑结构的复杂性,构造了一个新的四维超混沌系统.用数值模拟的方法研究了该系统的超混沌吸引子的相图、系统的分岔图、Lyapunov指数谱图和Lyapunov维数等.分析结果表明,新的四维系统当参数满足一定条件时,具有两个正的Lyapunov指数,是一个超混沌系统,系统的分岔图与Lyapunov指数谱是完全吻合的,随着参数变化呈现周期、混沌及超混沌动力学行为.利用线性反馈控制法镇定了超混沌系统的不稳定平衡点,数值模拟结果表明该方法的可行性和有效性.     

DUAL STROKE AND PHASE CONTROL AND SYSTEM IDENTIFICATION OF LINEAR COMPRESSOR OF A SPLIT-STIRLING CRYOCOOLER

A new dual control scheme is proposed for stroke and phase compensation for the displacement of a linear compressor in a split-Stirling cryocooler. This dual controller has two connected stroke and phase control loops, whose dynamic models are identified experimentally. These loops individually provide corrections which enable the stroke and phase of the compressor displacement to follow a sinusoidal command. Experimental results show that the dual stroke and phase control system is robust to parameter changes and external disturbances.     

奇异最优控制和负载观测器在直流随动系统中的应用

本文就电随动系统的奇异最优控制问题作了进一步的研究.考虑了负载力矩对于最优控制律的影响,采用观测器对分段常值型未知负载力矩进行估值,并据此在线修正最优开关曲线,从而使系统具有适应性.     

Current‐mode control of DC–DC power converters: a backstepping approach

Current‐mode control is a robust industrial DC–DC power converter control scheme that has been successfully tested, is widely accepted, and is commonly implemented with conventional linear P and PI controllers. The need of more systematic designs with enhanced performance has motivated recent studies with linear and nonlinear advanced techniques, but the rigorous understanding and substantiation of the underlying key robust functioning capability are still lacking. In this paper, a constructive control approach is employed to study the current‐mode control problem of a class of DC–DC power converters, yielding a cascade control design methodology with: a robust convergence criterion coupled with a systematic and transparent construction‐tuning procedure, a rationale to explain the robust controller functioning, and a unified framework to interpret and compare the proposed controller with the existing conventional and advanced control designs. The implementation and functioning of the proposed control design is illustrated experimentally with a boost converter. Copyright © 2003 John Wiley & Sons, Ltd.     

线性最优控制系统优化设计—权矩阵满阵优化法

本文通过线性最优控制理论、灵敏度分析理论及优化理论的有机结合,提出了一种系统的权矩阵优化选取方法.本方法在设计人员给定主导特征根位置、反馈增益顶值限制、寻优步长等条件下自动寻优,求得满足给定条件的权矩阵.同时为了最大限度地发挥权矩阵的作用,采用对权矩阵进行满阵优化的方法,大大提高了优化效率。实例表明,本方法能方便而快速地求得所需的权矩阵,解除了设计人员通过试凑法选取合适权矩阵的沉重负担.特别是用本方法所设计的降阶反馈控制系统较之一般常用的最小误差激励法所得到的降阶反馈控制系统具有更优良的动态品质.     

ANALYSIS AND DESIGN OF ONE‐BIT NOISE‐SHAPING QUANTIZER USING VARIABLE STRUCTURE CONTROL APPROACH

This paper offers a straightforward analysis of a one‐bit noise‐shaping quantizer based on variable structure control methods. The method uses the concept of equivalent control to access the bound on the state signals when the sliding condition is reached. For a stable loop filter, the global stability can be proved to exist by using the Lyanpunov stability theory. For an unstable loop filter, this paper proposes a state constraint approach to ensure that the sliding condition is achieved. Simulation examples and an experimental circuit constructed using off‐the‐shelf electronic components are given to demonstrate the correctness of the theoretical analysis.     

Galerkin‐based sliding mode tracking control of non‐minimum phase DC‐to‐DC power converters

Output voltage control of nonlinear DC‐to‐DC power converters is handicapped by the non‐minimum phase character exhibited by these systems. The problem has been usually solved with indirect control strategies that work through the input current. In this article, we report a robust control methodology that uses Galerkin‐based sliding manifolds, which use full state reference profiles and an estimate of the disturbed load parameter. The sliding surface incorporates a first‐order Galerkin approximation of the input current that provides robustness to piecewise constant load perturbations by dynamic compensation: it allows on‐line accommodation to the action of the load estimator. This results in high‐accuracy tracking of periodic references at the output resistance of boost and buck‐boost converters. Copyright © 2006 John Wiley & Sons, Ltd.     

STATE FEEDBACK CONTROLLER DESIGN OF NETWORKED CONTROL SYSTEMS WITH PARAMETER UNCERTAINTY AND STATE‐DELAY

This paper is concerned with the controller design of networked control systems. The continuous time plant with parameter uncertainty and state delay is studies. A new model of the networked control system is provided under consideration of the nonideal network conditions. In terms of the given model, a controller design method is proposed based on a delay dependent approach. The maximum allowable synthetical bounds related with the discarded data packet and network‐included delay and the feedback gain of a memoryless controller can be derived by solving a set of linear matrix inequalities for the stabilizablity of the networked control system based on Lyapunov functional method. An example is given to show the effectiveness of our method.     

VOLTAGE REGULATION OF A BUCK BOOST CONVERTER—A HYBRID CONTROL APPROACH

In this paper, the output voltage regulation problem in a buck boost converter is defined as a hybrid control problem. For control design, the mutually interacting continuous and discrete dynamics are modeled as a hybrid automaton. Thus, the control problem is defined as a guard selection problem of the hybrid automaton. The system trajectory is switched between different modes based on the guards to achieve the required voltage regulation. The guards defined are fixed surfaces represented in terms of the state variables for a given operating condition. The logic‐based switching in the state plane is stable in terms of the chaotic and bifurcation behavior. The effectiveness of the control scheme for buck and boost operation under line and load disturbances is demonstrated by simulation in the MATLAB‐SIMULINK environment and the results are presented.     

NEW TUNING METHOD FOR PID CONTROL OF A PLANT WITH UNDER‐DAMPED RESPONSE

In this paper, a tuning formula is derived for PID control of plants with under‐damped step responses. The under‐damped systems are modeled by second‐order plus dead time transfer functions. To derive the tuning rule, the dominant pole assignment method was applied to design the PID controllers for a variety of plant models. Then, the correlation between the controller parameters and the parameters of the models was found and the tuning formula derived. Several simulation examples are given to demonstrate the effectiveness and robustness of this formula.     

SLIDING MODES, Δ‐MODULATORS,AND GENERALIZED PROPORTIONAL INTEGRAL CONTROL OF LINEAR SYSTEMS

In this article, we attempt a reapproachment between sliding mode control of linear systems and classical control through the possibilities of evading state measurements and circumventing the use of asymptotic state observers in the sliding surface synthesis. This is shown to be possible thanks to the use of integral state reconstructors combined with iterated integral output error compensation. The proposed scheme is also robust with respect to unmatched perturbation inputs. A connection between sliding modes and classical analog Δ‐modulators, and their natural generalization, is also brought to attention as a tool for the realization of integral reconstructor based sliding mode control schemes.     

基于精细积分理论与算法体系的时变最优控制方案工程应用

以航天器的编队飞行控制为工程背景,利用PIMCSD工具箱设计了航天器远/近程逼近的时变控制方案,并在飞行控制仿真平台上通过了验证.仿真结果表明,相对于传统的定常控制器方案,新的时变控制器方案可以在更短的控制时间内,以更少的燃料消耗,达到更高的终端控制精度,从而验证了控制方案的可行性、有效性和先进性.同时,提出的时变控制器简化实现方案不仅可以保持良好的性能指标,也便于工程设计和实现.这些工作为航天器编队控制系统的工程设计提供了有益的参考.     

COMPARATIVE STUDY OF FUZZY CONTROL,PID CONTROL,AND ADVANCED FUZZY CONTROL FOR SIMULATING A NUCLEAR REACTOR OPERATION

Based on the background of fuzzy control applications to the first nuclear reactor in Belgium (BR1) at the Belgian Nuclear Research Centre (SCK˙CEN), we have made a real fuzzy logic control demo model. The demo model is suitable for us to test and compare some new algorithms of fuzzy control and intelligent systems, which is advantageous because it is always difficult and time-consuming, due to safety aspects, to do all experiments in a real nuclear environment. In this paper, we first report briefly on the construction of the demo model, and then introduce the results of a fuzzy control, a proportional-integral-derivative (PID) control and an advanced fuzzy control, in which the advanced fuzzy control is a fuzzy control with an adaptive function that can self-regulate the fuzzy control rules. Afterwards, we present a comparative study of those three methods. The results have shown that fuzzy control has more advantages in terms of flexibility, robustness, and easily updated facilities with respect to the PID control of the demo model, but that PID control has much higher regulation resolution due to its integration term. The adaptive fuzzy control can dynamically adjust the rule base, therefore it is more robust and suitable to those very uncertain occasions.     

OUTPUT‐FEEDBACK CONTROL OF CONTAINER CRANES: A COMPARATIVE ANALYSIS

A number of advanced control systems devoted to speed up the operation of container cranes have been proposed in the literature. In this paper the authors present a comparative analysis involving different control techniques applied to a laboratory sized gantry crane prototype. The comparison is carried out by means of both simulations and real experiments. In particular, two sliding‐mode control (SMC) schemes, a P.I.‐based controller and a linear observer‐based time‐varying feedback scheme are compared. The control algorithms have been suited to the path tracking problem of a suspended mass in order to make the comparison more effective.     

ROBUST OUTPUT FEEDBACK GUARANTEED COST CONTROL FOR 2‐D UNCERTAIN STATE‐DELAYED SYSTEMS

This paper considers the robust guaranteed cost control problem of two‐dimensional (2‐D) state‐delayed systems. First, the definition of guaranteed cost matrix is proposed and an upper bound of the cost function is given. Then, the guaranteed cost control problem is resolved. Furthermore, the minimum upper bound of the closed‐loop cost function is obtained by solving an optimization problem with LMIs' constraints. A numerical example demonstrates the effectiveness of our results.     

转炉吹炼实时控制专家系统RESC的设计与实现

本文分析了一个转炉吹炼实时控制专家系统ＲＥＳＣ的设计与实现，在开发中系统采用了专家系统技术，实时控制技术和吹炼控制模型相结合的方法，这里着重讨论了ＲＥＳＣ的系统结构，知识表示与推理机制，吹炼控制机制，网络通信以及主析实现技术。     

SCHEDULING AND CONTROL CO‐DESIGN FOR DELAY COMPENSATION IN THE NETWORKED CONTROL SYSTEM

The networked control system (NCS) is currently receiving increasing attention from researchers. Researches on this subject, however, have not considered the co‐design of network quality of service (QoS) and control quality of performance (QoP). This paper proposes a novel NCS design framework based on scheduling and control co‐design to compensate for random network‐induced delays. In the framework, a scheduling algorithm used to find the optimal sampling regions of control loops performs rough adjustment and guarantees the network QoS, while a novel adaptive fuzzy PID controller is designed to perform accurate adjustment to guarantee the control QoP. Practical application results obtained with a multi‐loop NCS show that the framework can ensure satisfactory performance due to its robustness against network uncertainty.     

REDUCED‐ORDER MODELS FOR FEEDBACK STABILIZATION OF LINEAR SYSTEMS WITH A SINGULAR PERTURBATION MODEL

The problem of output feedback stabilization of linear systems based on a reduced‐order model is addressed in this paper. New reduced‐order models are proposed for the output feedback design of linear systems with a singular perturbation model. An output feedback controller with a zero steady‐state gain matrix is proposed for stabilizing this kind of system. It is shown that with the proposed controller the reduced‐order model based feedback design can guarantee the actual closed‐loop stability for the sufficiently small perturbation parameter. This approach can overcome the difficulties in the existing design method using the so‐called zeroth‐order approximation model, whose validity is highly dependent on the value of the perturbation parameter.