Power-shaping control of reaction systems: The CSTR case

Power-shaping control is a recent approach for the control of nonlinear systems based on the physics of the dynamical system. It rests on the formulation of the dynamics in the Brayton-Moser form. One of the main obstacles for using the power-shaping approach is to write the dynamics in the required form, since a partial differential equation system submitted to sign constraints has to be solved. This work comes within the framework of control design approaches that could possibly generate a closer link between the notions of energy that are specific to reaction systems as derived from thermodynamics concepts, and the dynamic system stability theory. The objective of this paper is to address the design of power-shaping control to reaction systems, and more particularly the step of solving the partial differential equation system. In order to illustrate the approach, we have selected the classical yet complex continuous stirred tank reactor (CSTR) as a case study. We show how using the power-shaping approach leads to a global Lyapunov function for the unforced exothermic CSTR. This Lyapunov function is then reshaped by means of a controller in order to stabilize the process at a desired temperature.     

A dual relation between port-Hamiltonian systems and the Brayton-Moser equations for nonlinear switched RLC circuits

In the last decades, several researchers have concentrated on the dynamic modeling of nonlinear electrical circuits from an energy-based perspective. A recent perspective is based on the concept of port-Hamiltonian (PH) systems. In this paper, we discuss the relations between the classical Brayton-Moser (BM) equations—stemming from the early sixties—and PH models for topologically complete nonlinear RLC circuits, with and without controllable switches. It will be shown that PH systems precisely dualize the BM equations, leading to possible advantages at the level of controller design. Consequently, useful and important properties of the one framework can be translated to the other. Control designs for the PH model cannot be directly implemented since they require observation of flux and charges, which are not directly available through standard sensors, while the BM models require only observation of currents and voltages. The introduced duality allows to pull back PH designs to the space of currents and voltages. This offers the possibility to exchange several different techniques, available in the literature, for modeling, analysis and controller design for RLC circuits. Illustrative examples are provided to emphasize the duality between both frameworks.     

基于网络的油田生产管理系统开发

任何企业在信息发展的特定阶段都有其发展的”瓶颈”．用先进的网络信息技术改造现有的信息运行模式．必须找准结合点同切入点．以较小投资尽快产生效益，华北油田采油四厂的目标就是要在原有的网络技术的基础上建成一个适合原油生产管理需求的综合网络应用体系．最终实现利用网络技术提高生产信息管理水平，为数字化油田作充分的准备工作、     

量子分子动力学中的操纵技术及其系统控制理论

回顾了量子操纵技术在分子化学动力学控制中的发展历程及其技术的分类与效果,并就不同操纵技术的原理以及实现上的特点进行了分析和对比,其中包括:频域中的π脉冲动力学法和干涉路径控制方案,时域中的激光脉冲成型操纵技术,继而对宏观控制理论在分子化学动力学控制中的发展状况给予逐一的阐述及评价,包括系统建模、分析与综合、几何控制、幺正演化矩阵控制、最优控制、基于李雅普诺夫方法的控制等.对全面了解量子化学中动力学操纵技术及其控制理论的应用提供一个全方位的综述.     

Analysis and control of the cable-supporting system including actuator dynamics

This paper is concerned with modeling, analysis, and control of the cable-supporting system including actuator dynamics for the next generation large spherical radio telescope. According to its 50-m scaled model, to begin with, the dynamic formulations of the electromechanical coupling system including servomechanism dynamics and parabolic curve of the long-span cable sag effects are established; at the same time the relationship among cable force, cable end displacement and cable length variation is obtained by utilizing parabolic equation, and the dynamic modeling for control can be justified by the numerical example. In addition, taking account of the characteristics of nonlinearity, slow time-variant and multivariable coupling, a fuzzy control plus proportional-integral control method is utilized to control the wind-induced vibration of the cable-supporting system. Finally, simulation results from the 50-m scaled model control system, regarding the wind-induced vibration control of the cable-supporting structure in stationary position and the tracking control of the cable-supporting system, show the satisfactory performance of the proposed control scheme as compared with a discrete-time automatic disturbances rejection controller in the presence of internal model uncertainties in both the cable-supporting mechanism and servomechanism dynamics and external disturbances.     

基于PHP网站的远程控制系统研究

在传统的远程控制领域,基于C/S模型的系统造成了控制端配置操作的复杂化,控制人员不得不花费大量时间去学习、配置控制端。PHP(Hypertext Preprocessor)作为B/S动态网站开发领域内最快速的一种服务器端脚本语言,将其使用于远程控制系统中,给控制人员提供一种无需固定控制端、无需安装配置的形态来控制远程系统。本文给出了远程控制系统的架构,介绍了具体的数据通信方法,使用数据库来实现对整个系统命令及状态的记录和传输,使服务器能通过互联网实现对远程设备的监控。     

温度控制在屏蔽泡棉生产中的应用

引入以PLC为核心的模糊控制方法来设计恒温控制系统,以解决产品溢胶问题.结果表明:该系统具有较高的稳定性、控制精度和品质.     

规范形Qi系统的Hopf分岔分析及控制

文章研究了一个Qi系统的Hopf分岔控制问题.根据计算的极限环曲率系数,判定原系统的Hopf分岔类型,并采用washout滤波器控制该系统的分岔行为.首先讨论了控制器的线性增益对Hopf分岔点位置的影响,然后引入规范形计算方法,求出受控系统的Hopf分岔规范形.分析了规范形中系数对控制参数的选择原则所产生之影响,以及对Hopf分岔类型及极限环幅值的影响.理论和仿真结果表明,控制器的线性增益能使原系统的Hopf分岔点延迟或消失,而非线性增益能则改变极限环的稳定性和极限环幅值的大小.最后把washout滤波器和线性控制器的控制效果作了对比,发现washout滤波器比之线性控制器具有一定的优势.     

异结构超混沌系统动力学分析和同步控制策略研究

基于混沌同步控制理论研究,结合同步控制与线性反馈控制方法,提出一种针对异结构超混沌系统的同步控制策略.在Chua混沌系统和Chen混沌系统理论研究基础上,通过增加两个反馈控制器得到两个异结构五阶混沌系统,对其进行动力学分析,证实其为五阶超混沌系统,并基于Mathmatic环境下对其模型进行数值仿真,得到其平面相图.采用全状态投影同步方法实现对其同步控制,并用龙格-库塔算法进行数值模拟,证实该同步方法有效可行.     

Minimum entropy control of nonlinear ARMA systems over a communication network

In this paper, the entropy concept has been utilized to characterize the uncertainty of the tracking error for nonlinear ARMA stochastic systems over a communication network, where time delays in the communication channels are of random nature. A recursive optimization solution has been developed. In addition, an alternative algorithm is also proposed based on the probability density function of the tracking error, which is estimated by a neural network. Finally, a simulation example is given to illustrate the efficiency and feasibility of the proposed approach.     

Adaptive inverse dynamics control of robots with uncertain kinematics and dynamics

It has been about two decades since the first globally convergent adaptive tracking controller was derived for robots with dynamic uncertainties. However, not until recently has the problem of concurrent adaptation to both the kinematic and dynamic uncertainties found its solution. This adaptive controller belongs to passivity-based control. Though passivity-based controllers have many attractive properties, in general, they are not able to guarantee the uniform performance of the robot over the entire workspace. Even in the ideal case of perfect knowledge of the manipulator parameters, the closed-loop system remains nonlinear and coupled. Thus the closed-loop tracking performance is difficult to quantify, while the inverse dynamics controllers can overcome these deficiencies. Therefore, in this work, we will develop a new adaptive Jacobian tracking controller based on the inverse manipulator dynamics. Using the Lyapunov approach, we have proved that the end-effector motion tracking errors converge asymptotically to zero. Simulation results are presented to show the performance of the proposed controller.     

Non-linear dynamics in adaptive control: Chaotic and periodic stabilization

In this paper the non-linear features of adaptive control algorithms are highlighted. Using a simple “linear” discrete time example, based on classical design, it is demonstrated that in the presence of undermodelling errors, non-linear phenomena in the feedback gain such as limit cycles and even chaos arise. Despite these complicated dynamics, robust stabilization of the plant can still occur. For the class of undermodelling errors considered, the set of plants stabilizable by this adaptive controller is completely characterized.     

产品随机缺陷生产系统有限时域最优生产控制

针对合格产品产量呈随机分布的单设备单产品类型不可靠生产系统,假设所生产合格产品的产量占所生产产品总量比例的概率分布已知,且产品质量检测消耗时间与生产控制时域相比较小.本文通过对目标函数的离散化,在离散空间上对生产控制策略进行寻优,得到基于当前状态下的最优生产控制策略,该策略可解析表示为合格产品产量分布、成本惩罚系数c~ (c~-)、当前状态及产品质量检测时间的函数.与同类文献所得结果相比较,该控制策略克服了文献[8]结论有可能导致系统状态发散的缺点,并且最优控制策略表达式更简洁,所得结论对实际工程应用而言有显著意义.     

Recurrent neural block form control

By modifying some previously developed results for nonlinear identification and control using recurrent neural networks, the present authors propose a new neural network identifier in block form, and, based on this model, a control law is developed by combining sliding mode and block controls. This neural identifier and control law allow satisfactory trajectory tracking for general nonlinear systems. Applicability of the new design is illustrated, via simulations, for robust tracking control of stepping motors.     

Service process control: conceptualising a service as a feedback control system

This paper shows how a service process can be recast into a feedback control structure and how chemical process control principles can be applied. The outputs of the ‘service plant’ are process characteristics that meet the requirements of the plant's various stakeholders; the manipulated and disturbance variables are those variables that are within and outside a service manager's control respectively; the model is a process flowchart; and the controller is the service manager. Good stability, performance and robustness are also required because customers value reliability, responsiveness, and consistency of service in the face of variations caused by involvement of people in the service delivery. To illustrate these concepts, a patient treatment process within an emergency ward was recast as a control system, and an off-line model-based optimal controller was applied to this stochastic process. The benefits of recasting services as feedback control systems flow both ways: service design and operation will be improved by the application of engineering principles; and chemical process control will benefit from techniques specially developed to handle market fluctuations.     

Pointwise control of the Boussinesq system

We study a pointwise control problem for the Boussinesq system in two dimensions. The control is a source term in the heat equation, and the cost functional takes into account the distance between the solution to the Boussinesq system and a given profile. We have recently studied similar problems for the linearized Boussinesq system (Nguyen and Raymond, J. Optim. Theory Appl. 141 (2009) 147-165). Studying these problems in the nonlinear case is more difficult. There is some literature on the pointwise control of linear and nonlinear partial differential equations; however, to the authors’ knowledge, nothing has been done for the Boussinesq system. In this study, we prove the existence of optimal solutions and derive optimality conditions.     

智能协同集成逆向工程系统控制模型的研究

为提高集成逆向工程系统的智能和协同能力,提出了基于MAS的控制模型。该模型分为管理智能体层、单元智能体层和执行智能体层。管理智能体层负责调度和协调各CA,并对所有CA进行管理;单元智能体层中的各CA间通过协商承担相应的任务,完成任务的一级分配;执行智能体对逆向系统内的硬件、软件负责,它们根据局部的本地资源信息及当前状态,接收发布的任务,并对其求解。同一层次的CA之间采用分布式结构,对等协作;上下级的CA间采用主从协作。     

高炉喷吹焦炉煤气自动控制系统

介绍了高炉喷吹焦炉煤气的工艺、自动控制系统、控制参数及控制方法.该系统节能环保,在国内率先应用,能提高焦炉煤气价值和能量利用率,创造了可观的经济效益和社会效益.全自动化程度高,所有联锁和控制全部自动化,完全满足喷吹焦炉煤气工艺生产和安全的要求.该系统具有极大的推广应用价值,特别对于焦炉煤气放散还未合理利用的中小钢铁企业效益更加明显.