Gray-fuzzy control of a nonlinear two-mass system

This study presents application of a fuzzy controller to a nonlinear two-mass system control. The proposed controller structure is strengthened with a gray estimator. Firstly, a complete state-space mathematical model for a nonlinear two-mass system is developed and numerically simulated. Then, a fuzzy controller is designed to regulate the speed of the system. In order to perform a dynamic and powerful control action, future error values are estimated by gray modeling technique. The gray estimators of the torsional torque and the load machine speed are tested with open-loop and closed-loop control structures to test the robustness of the proposed method for step changes in input parameters. It is observed that the tracking ability of the gray estimators is not influenced for different operation modes. The performances of the control structures, which are supported with gray estimators, are given and no additional feedbacks are required for robust control action. The simulation results are confirmed by experimental results and conclusions are given.     

Substructural control of fuzzy nonlinear flexible structures

It is advantageous to use the substructural and/or decentralized techniques in structural control to save on computations and time. In this paper, a generalized substructural approach is presented in the control of fuzzy nonlinear flexible structures with discrete sensors/actuators. The substructural control scheme is developed using the static condensation technique together with the LQG control method. The subcontrollers and subobservers designed at substructure levels are used to assemble the global controller and observer for the whole structure. Nonlinear effects are included in the structural formulations and a fuzzy methodology is adopted for handling the imprecision present in the structure modeling. The nonlinear and fuzzy schemes are applied to one structural control problem to illustrate the accuracy and capability of the substructural control technique.     

Permissible control of general constrained mechanical systems

This paper develops a unified approach for modeling and controlling mechanical systems that are constrained with general holonomic and nonholonomic constraints. The approach conceptually distinguishes and separates constraints that are imposed on the mechanical system for developing its physical structure between constraints that may be used for control purposes. This gives way to a general class of nonlinear control systems for constrained mechanical systems in which the control inputs are viewed as the permissible control forces. In light of this view, a new and simple technique for designing nonlinear state feedback controllers for constrained mechanical systems is presented. The general applicability of the approach is demonstrated by considering the nonlinear control of an underactuated system.     

A PI controller configuration for robust control of a class of nonlinear systems

The PI control configuration for stabilization and signal tracking of nonlinear systems is investigated. Semiglobal asymptotic stability and semiglobal practical signal tracking of the controlled system are proven using results from the theory of nonlinear singularly perturbed systems.     

Robust adaptive tracking with an additional plant identifier for a class of nonlinear systems

In this paper, we develop two new model reference adaptive control (MRAC) schemes for a class of nonlinear dynamic systems that is robust with respect to an uncertain state (output) dependent nonlinear perturbations and/or external disturbances with unknown bounds. The design is based on a controller parametrization with an adaptive integral action. Two types of adaptive controllers are considered—the state feedback controller with a plant parameter identifier, and the output feedback controller with a linear observer.     

"一体化"教学模式与《电工与电子技术》课程教学

《电工与电子技术》是建筑设备工程技术专业的一门必修专业基础课程，具有实践性强的特点，实践证明，采用“一体化”教学模式，将理论学习与实际训练紧密结合起来，在学练中理解理论知识、掌握技能，实现高等职业教育的培养目标。     

Tracking control of nonlinear automobile idle-speed time-delay system via differential geometry approach

This paper is concerned with the problem of global asymptotical tracking of single-input single-output (SISO) nonlinear time-delay control systems. Based on the input-output feedback linearization technique and Lyapunov method for nonlinear state feedback synthesis, a robust globally asymptotical output tracking controller design methodology for a broad class of nonlinear time-delay control systems is developed. The underlying theoretical approaches are the differential geometry approach and the composite Lyapunov approach. One utilizes the parameterized co-ordinate transformation to transform the original nonlinear system into singularly perturbed model and the composite Lyapunov approach is then applied for output tracking. For the view of practical application, the proposed control methodology has been successfully applied to the famous nonlinear automobile idle-speed control system.     

Observer based fault-tolerant control for a class of nonlinear networked control systems

In this paper, we present a fault-tolerant control (FTC) framework for a class of nonlinear networked control systems (NCSs). Firstly, the plant is transformed into two subsystems with one of them decoupled from the system fault. Then, the nonlinear observer is designed to provide the estimation of unmeasurable state and modelling uncertainty, which are used to construct fault estimation algorithm. Considering the sampling intervals occurred by net, a fault-tolerant control method is proposed for such nonlinear NCSs using the impulsive system techniques. The controller gain and the maximum sampling interval, which make the faulty system stable are given. An example is included to show the efficiency of the proposed method.     

公路工程建设项目成本控制体系的构建

针对我国公路工程建设项目的成本控制问题，提出建立成本控制体系的构想，首先应建立成本控制组织机构，其次在设计与投标阶段和施工现场进行成本控制，最后在工程竣工后进行成本的审查与反馈。     

广西电视台播控系统安全性设计

文章从视频服务器系统,数据库服务器,播出控制系统,系统防病毒措施,时钟及同步系统和供电系统等方面充分阐述广西电视台在系统安全性的设计上的考虑。     

Guaranteed-cost reliable control with regional pole placement of a power system

This paper deals with the simultaneous coordinated design of power system stabilizer (PSS) and the flexible ac transmission systems (FACTS) controller. The problem of guaranteed cost reliable control with regional pole constraint against actuator failures is investigated. The state feedback controllers are designed to guarantee the closed loop system satisfying the desired pole region, thus achieving satisfactory oscillation damping and settling time, and having the guaranteed cost performance simultaneously. The proposed controllers satisfy desired dynamic characteristics even in faults cases. The controller's parameters are obtained using the linear matrix inequalities (LMI) optimization. Simulation results validate the effectiveness of this approach.     

Design and comparison of LQG/LTR and H∞ controllers for a VSTOL flight control system

In this paper two robust controllers for a multivariable vertical short take-off and landing (VSTOL) aircraft system are designed and compared. The aim of these controllers is to achieve robust stability margins and good performance in step response of the system. LQG/LTR method is a systematic design approach based on shaping and recovering open-loop singular values while mixed-sensitivity H_∞ method is established by defining appropriate weighting functions to achieve good performance and robustness. Comparison of the two controllers show that LQG method requires rate feedback to increase damping of closed-loop system, while H_∞ controller by only proper choose the weighting functions, meets the same performance for step response. Output robustness of both controllers is good but H_∞ controller has poor input stability margin. The net controller order of H_∞ is higher than the LQG/LTR method and the control effort of them is in the acceptable range.     

加强控制系统可靠性 降低溢流堰故障率

介绍了邯郸市东污水处理厂通过调整三沟式氧化沟溢流堰控制系统,降低了溢流堰故障率,提高了工作效率,进而达到节约成本目的的过程。     

Observer-based sliding mode control for a class of uncertain nonlinear neutral delay systems

In this paper, the observer-based sliding mode control (SMC) problem is investigated for a class of uncertain nonlinear neutral delay systems. A new robust stability condition is proposed first for the sliding mode dynamics, then a sliding mode observer is designed, based on which an observer-based controller is synthesized by using the SMC theory combined with the reaching law technique. Then, a sufficient condition of the asymptotic stability is proposed in terms of linear matrix inequality (LMI) for the overall closed-loop system composed of the observer dynamics and the state estimation error dynamics. Furthermore, the reachability problem is also discussed. It is shown that the proposed SMC scheme guarantees the reachability of the sliding surfaces defined in both the state estimate space and the state estimation error space, respectively. Finally, a numerical example is given to illustrate the feasibility of the proposed design scheme.     

试论现代企业内部控制评价体系的建设

企业内部控制是现代企业良性发展的管理趋势,其行为特征为“控制自我评估”,是指企业在一定时期内,定期或不定期对内部控制体系进行自我评价,评估内部控制的有效性及效率性,使之能更好地达到内部控制目标。基本特征为重点关注经营生产业务的过程和过程控制的效果;这样的“控制自我评估”一般由企业相关部门和人员共同完成。     

Minimal energy maneuvering control of a rigid spacecraft with momentum transfer

The main goal of this study is to investigate a minimal energy rest-to-rest maneuvering control problem with open final time of a rigid spacecraft actuated by three orthogonal momentum wheels. Different from conventional shooting methods, this control problem is formulated and solved as a constrained nonlinear programming (NLP) one by utilizing an iterative procedure. In this novel method, the count of control steps is fixed initially and the sampling period is treated as a variable in the optimization process. An approach to find the initial feasible solutions of the NLP problem is also proposed. Since initial feasible solutions can be found easily, the optimization process of the NLP problem can be started from different points to find the minimal energy rest-to-rest maneuver of the rigid spacecraft between two attitudes. To show the feasibility of the proposed method, simulation results are included for illustration.     

变电站端子箱温湿度监控系统的探讨

实际运行经验表明,变电站户外端子箱加热器的故障率较高,降低了端子箱的防潮能力,增大了设备的运行风险。基于这种情况,文章从数字化变电站的理论出发,进行了变电站端子箱温湿度监控系统的初步设计,通过确定通讯路径和设定告警逻辑,使后台掌控户外端子箱的运行环境成为可能。     

A new method for fault prediction of model-unknown nonlinear system

In this paper, the subspace identification based robust fault prediction method which combines optimal track control with adaptive neural network compensation is presented for prediction the fault of unknown nonlinear system. At first, the local approximate linear model based on input-output of unknown system is obtained by subspace identification. The optimal track control is adopted for the approximate model with some unknown uncertainties and external disturbances. An adaptive RBF neural network is added to the track control in order to guarantee the robust tracking ability of the observation system. The effect of the system nonlinearity and the error caused by subspace modeling can be overcome by adaptive tuning of the weights of the RBF neural network online without any requisition of constraint or matching conditions. The stability of the designed closed-loop system is thus proved. A density function estimation method based on state forecasting is then used to judge the fault. The proposed method is applied to fault prediction of model-unknown fighter F-8II of China airforce and the simulation results show that the proposed method can not only predict the fault, but has strong robustness against uncertainties and external disturbances.     

ZigBee技术在门禁系统的应用

现行市场的门禁系统中,现场总线一统天下,但随着社会的发展,它的缺陷越来越明显。本文提出了ZigBee技术在门禁系统的一个应用实例,主要讲述了ZigBee的基本概念、整个应用的网络结构、门禁控制器的硬件实现、数据传输机制和安全性等方面的内容。