T-S模糊系统的局部稳定

讨论了T-S模糊系统的局部稳定性及控制器设计问题．给出连续T-S模糊系统局部稳定的定义，利用非二次Lyapunov函数和线性矩阵不等式（LMI）方法得到连续T-S模糊系统局部稳定的充分条件，并给出了基于LMI的局部镇定控制器设计方法．该方法不同于已有的全局稳定控制器设计方法，为判别模糊系统的稳定提供了新的选择．最后通过数值算例演示了控制器的设计方法。并证明了该方法的可行性。     

Parallel simulation of DEDS via event synchronization

In this paper we use the event synchronization scheme to develop a new method for parallel simulation of many discrete event dynamic systems simultaneously. Though a few parallel simulation methods have been developed during the last several years, such as the well-known Standard Clock method, most of them are largely limited to Markovian systems. The main advantage of our method is its applicability to non-Markovian systems. For Markovian systems a comparison study on efficiency between our method and the Standard Clock method is done on Connection Machine CM-5. CM-5 is a parallel machine with both SIMD (Single Instruction, Multiple Data) and MIMD (Multiple Instruction Multiple Data) architectures. The simulation results show that if event rates of Markovian systems do not differ by much then both methods are compatible but the Standard Clock method performs better in most cases. For Markovian systems with very different event rates, our method often yields better results. Most importantly, our simulation results also show that our method works as efficiently for non-Markovian systems as for Markovian systems.     

An alternative algebra for deriving equations of motion of flexible manipulators

An alternative means for deriving equations of motion of complex systems is demonstrated. Since the method is energy based, it is useful for elastic systems. Because the method can handle vectors expressed relative to rotating coordinate systems, it does not require the introduction of coordinate transformations and thereby produces equations in a simple form. The article shows that Kane's method for rigid body systems is a special case of this alternative method. Two example problems show how the algebra can be applied to rigid and flexible nonholonomic systems.     

Receding horizon control of nonlinear systems

The receding horizon control strategy provides a relatively simple method for determining feedback control for linear or nonlinear systems. The method is especially useful for the control of slow nonlinear systems, such as chemical batch processes, where it is possible to solve, sequentially, open-loop fixed-horizon, optimal control problems online. The method has been shown to yield a stable closed-loop system when applied to time-invariant or time-varying linear systems. It is shown that the method also yields a stable closed-loop system when applied to nonlinear systems     

Pseudo‐energy shaping for the stabilization of a class of second‐order systems

A Lyapunov direct method is presented for a class of second‐order systems that includes mechanical systems. This method shall be called a pseudo‐energy shaping method because it reduces to the energy shaping method when a given second‐order system is a mechanical system. The pseudo‐energy shaping method comprehends both the Lyapunov direct method for mechanical systems proposed by Aguilar‐Ibañez and the controlled Lagrangian method that has been successfully applied to stabilize mechanical systems. A class of second‐order systems including mechanical systems is defined first. For this class, matching conditions are derived for the construction of an energy‐like Lyapunov function that shall be called a pseudo‐energy function. Easily verifiable conditions are then presented for stabilizability by the pseudo‐energy shaping method for a class of second‐order linear systems and for a class of second‐order nonlinear systems with one degree of under‐actuation. These results are applied to stabilize a two‐dimensional overhead crane system and a three‐link robot arm system. Copyright © 2011 John Wiley & Sons, Ltd.     

一种实值属性信息系统的粗集约简方法

本文研究应用粗集理论对实值信息系统属性进行约简的方法，对实值属性信息系统进行约简的根本问题是如何对实值属性离散化，通过对离散化方法与属性约简的关系进行研究，提出实值属性离散化的一种自动确定属性类别的方法，并结合粗集理论给出了对实值属性信息系统约简的算法，用所提出的算法进行了实验，并给出了实验结果。     

基于不确定理论的复杂体系优化方法研究

为研究复杂体系的优化方法,首先针对复杂体系的三个发展阶段,提出了三类优化问题;其次通过研究体系结构、体系能力和体系效能之间的内在关系,给出了体系优化的思路,建立了以体系效能为优化目标的复杂体系优化模型;接着利用模糊集理论与证据理论讨论了体系能力评估中定性信息的定量化问题,探索了新的体系能力评估方法,并基于体系效能仿真,采用粗糙集理论建立了求解体系能力权值因子的算法;最后给出了求解优化模型的方法.所提出的优化方法为复杂体系优化问题提出了一种新思路.     

Output control design and separation principle for a class of port‐Hamiltonian systems

Using a structure preserving observer, a dynamic output controller is proposed for a class of port‐Hamiltonian systems. The core of this method is based on the notion of contractive port‐Hamiltonian systems. The proposed method utilizes an extended form of IDA‐PBC (interconnection and damping assignment passivity‐based control), a well‐known controller design method for port‐Hamiltonian systems and paves the way for using IDA‐PBC in output control design of challenging control objectives, such as output tracking for underactuated mechanical systems. In the line of output control design, a useful separation principle for a class of port‐Hamiltonian systems is achieved, which is valuable in the field of nonlinear systems. Some simulations on magnetic levitation and ball on wheel testbeds show the potency and applicability of the proposed method.     

离散事件系统部分可诊断性分析

针对离散事件系统部分可诊断性问题,提出一种量化评价与分析方法。该方法以树状结构的故障模型为基础,引入可诊断度与可诊断深度指标,能够从可诊断故障覆盖程度与精确程度两个方面对系统可诊断性进行评价,其优点是评价结果量化表示,能为部分可诊断系统的进一步评价、分析与对比提供参考。此外,还讨论了故障模型对系统可诊断度与可诊断深度两个评价指标的影响,并给出了故障模型构造的一般原则。实例分析与讨论结果表明,所提出的可诊断度与可诊断深度指标能够准确反映系统在特定故障模型下的部分可诊断状态。所提出的部分可诊断性评价方法能为基于离散事件模型的复杂系统设计与评价提供依据,并能够进一步为智能、自适应和自愈系统的设计提供参考。     

Comparisons of practical hierarchical control methods for interconnected dynamical systems

This paper gives a brief survey of possible methods which can be used for the practical control of large interconnected dynamical systems. The development is in two parts, i.e. optimal methods and suboptimal methods. In the first part, a brief outline is given of infeasible methods like Goal co-ordination and the Takara-Sage algorithm. In the general study of infeasible methods, Tamura's three-level method, Tamura's time-delay method and Pearson's pseudo-model co-ordination method are also included. It is seen that both the algorithms of Tamura as well as the Takahara-Sage method are particularly suited to systems with slow dynamics whereas Pearson's pseudo-model co-ordination method could be used advantageously for systems with fast dynamics.A practical example is then given of optimal traffic control using an infeasible method, in this case the time-delay method of Tamura. The main conclusion to emerge from this part is that optimal methods will require multiple processors for on-line dynamic optimization although for systems with slow dynamics like the traffic example, fairly large problems could nevertheless be tackled using only one processor.There are certain classes of systems for which it may be possible to obtain virtually optimal control using only a single processor even when the number of subsystems is very large. One such class of problems is of serially connected dynamical systems. In the second part of this paper a suboptimal approach is described for the control of serial systems and the method is demonstrated using river pollution as an example. Finally, a new method is developed which enables a significant improvement to be made for serial systems with conflicts between the subsystems and an example illustrates this approach.     

Variational embedding method and application to distributed systems control

The main aim of the present paper is to show the variational embedding method as a powerful tool for solving control problems associated with distributed systems. It is shown that, variational embedding subsumes many approximation methods that are available in the literature for solving constitutive equations of distributed systems. The well-known method of weighted residuals and its ramifications are shown to be the appropriate specializations of the embedding method. The method thus offers a vantage point from which it is conceptually easy to see both the plurality and unity of these methods. In the process of illustrating the hierarchy of the method, the attendant dilemma associated with the method of weighted residuals is successfully resolved. The variational embedding method yields a unified approach for obtaining lumped models for distributed parameter systems. The application is demonstrated by considering examples of engineering importance, and it is shown how lumped models of non-linear distributed systems could be constructed by methods other than the conventional discretization methods.     

时滞对象的自抗扰控制

时滞系统的控制在自动化领域具有重要意义。在剖析时滞系统控制的Smith预估法的本质的基础上,提出利用具有强大噪声抑制能力的"跟踪微分器"来实现"相位超前"、"相位滞后"等功能,从而解决时滞系统控制问题的新办法,其中包括把时滞算子近似成单位1的无视时滞法;把时滞算子近似成一阶惯性环节的提高阶次法;模仿Simith预估法把相位超前的虚拟输出当作被控量来进行无时滞对象控制的输出超前法;及引入虚似控制量的输入超前法等。相应的仿真研究表明,这些新方法都能控制好大时滞系统的控制问题,时滞大小已不再成为"难控"和"易控"的标准。     

基于神经网络误差修正的混沌控制与同步

针对混沌系统非线性强、多变量耦合等特点,提出了一种基于神经网络误差修正的自适应多变量混沌系统的广义预测控制算法,用线性广义预测控制器控制混沌系统,用神经网络对模型预测误差进行修正。算法中辩识过程模型用递推最小二乘法(RLS)、神经网络权值用Davidon最小二乘法(DLS)训练。这种算法对被控混沌系统的先验知识要求较少,无需知道被控系统的精确模型,数值仿真显示可实现混沌系统的宽范围控制与同步。     

Compensation method for non-linear systems having jump and hysteresis properties†

The paper introduces a novel method for describing non-linear systems. The method, which uses non-integer calculus provides greater insight into the physical aspects of jump and hysteresis phenomena in systems with single-valued non-linear characteristics. The method is well suited to non-linear systems having minimum phase-shift linear parts. A non-integer-order compensator is developed for singularities arising from non-linearities. To illustrate the scheme, saturation is considered. Numerical design of a compensator for jump and hysteresis is also described.     

采用双交叠模糊分划的T-S模糊系统的稳定性分析

研究前件变量采用双交叠模糊分划的T-S模糊系统的稳定性问题．首先针对自由系统，将连续时间系统的、基于最大交叠规则组的稳定性分析方法推广应用于离散时间系统，并采用模糊Lyapunov方法得到了稳定性的新结论．采用非并行分布补偿控制律，针对受控系统也得到了相应的结论．这些结论比已有的结果更加宽松．仿真例子验证了该稳定性结论．     

基于粗集的模糊属性值信息系统的知识获取

文章研究了一类属性取模糊值的不完备信息系统的知识获取方法。首先给出了信息系统的一种表示方法,同时采用模糊集思想,构造了这类系统的模糊不可分辨关系,并研究了这类信息系统的知识获取算法,并以一个实例,说明了这种算法的有效性。     

一种用于快速跟踪系统的MAC方法

通过对一类快速跟踪系统特点的分析,提出一种可用于这类系统的改进的MAC算法.文 中给出了该算法的计算公式,并且考虑了当系统的快速和加速度受到限制时的处理方法.该 算法具有较强的鲁棒性.由于计算量与存储量都很小,该算法可容易地用单片机实现.最后, 以一个仿真例子说明了该方法的可行性.     

Sliding-Mode Control of Retarded Nonlinear Systems Via Finite Spectrum Assignment Approach

In the present study, a sliding-mode control design method based on the finite spectrum assignment procedure is proposed. The finite spectrum assignment for retarded nonlinear systems can transform retarded nonlinear systems into delay-free linear systems via a variable transformation and a feedback, which contain the past values of the state. This method can be considered to be an extension of both the finite spectrum assignment for retarded linear systems with controllability over polynomial rings of the delay operator and the exact linearization for finite dimensional nonlinear systems. The proposed method is to design a sliding surface via the variable transformation used in the finite spectrum assignment and to derive a switching feedback law. The obtained surface contains not only the current values of the state variables but also the past values of the state variables in the original coordinates. The effectiveness of the proposed method is tested by an illustrative example.     

An all-coefficient adaptive control method for a class of nonlinear time-varying systems

In this paper, the extension of the all-coefficient adaptive control method to nonlinear time-varying systems is studied. A novel discretizing method is first proposed to derive the discrete-time model for a class of nonlinear time-varying systems. The characteristics of the coefficients of the discrete-time model are derived by this method, based on which the all-coefficient adaptive control method is given for the class of nonlinear time-varying systems. Sufficient conditions on the closed-loop stability ...     

Mini-max method for optimization of energy consumption in real-time systems with a lot of processing elements

The mini-max method is designed for the analysis and optimization of energy consumption in single-processor real-time systems and offers several advantages over alternative methods when used in single-task and multitask systems. There has been no research, however, dedicated to its use in real-time systems with several processing elements. This work deals with the use of the mini-max method in subsystems with two executive elements. Two methods for the organization of systems processing sequential task threads are proposed. The first method is a synchronous one with an allotted time period for each task, and the second method involves an asynchronous task stream. The analysis and comparison of these methods are performed, and their efficiency in solving the problem of energy consumption is shown.