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1.
This paper is concerned with the robust quantized feedback stabilization problem for a class of uncertain nonlinear large-scale systems with dead-zone nonlinearity in actuator devices. It is assumed that state signals of each subsystem are quantized and the quantized state signals are transmitted over a digital channel to the controller side. Combined with a proposed discrete on-line adjustment policy of quantization parameters, a decentralized sliding mode quantized feedback control scheme is developed to tackle parameter uncertainties and dead-zone input nonlinearity simultaneously, and ensure that the system trajectory of each subsystem converges to the corresponding desired sliding manifold. Finally, an example is given to verify the validity of the theoretical result.  相似文献   

2.
In this paper, the problem of adaptive fuzzy decentralized control is investigated for a class of pure-feedback nonlinear interconnected large-scale systems. During the controller design, fuzzy logical systems are used to model packaged unknown nonlinearities and backstepping technique is used to construct adaptive fuzzy decentralized controller. It is shown that the proposed control scheme can guarantee that all the signals in the closed-loop system are semiglobally uniformly ultimately bounded. The main advantage of this study lies in that only one adaptive parameter needs to be estimated online for each subsystem. Simulation results further illustrate the effectiveness of the suggested approach.  相似文献   

3.
A novel H tracking-based decentralized direct adaptive output feedback fuzzy controller is developed for a class of interconnected nonaffine uncertain nonlinear systems in this paper. By virtue of the proper filtering of the observation error dynamics to assure its strictly positive realness, the observer-based decentralized direct adaptive fuzzy control (DAFC) scheme is presented for a class of large-scale nonaffine nonlinear systems by the combination of H tracking technique, implicit function theorem, a state observer and a fuzzy inference system. The output feedback and adaptation mechanisms for each subsystem depend upon local measurements not only to achieve asymptotical tracking of a reference trajectory but to guarantee arbitrary small attenuation level of the mismatched errors and external disturbances on the tracking error. Simulation results confirm the effectiveness of the proposed decentralized output feedback scheme.  相似文献   

4.
董钢  王建国 《计算力学学报》2014,31(4):480-485,494
基于大系统分散控制思想,将大尺度高阶建筑结构系统分解为多个子结构系统;子结构之间的相互耦合作用视为有界广义力,得到以状态方程形式的子结构模型。利用滑模理论的抗摄动条件,设计具有全局稳定的子结构滑动模态轨迹,利用子结构系统局部状态实现全局稳定的控制力条件,并以参数ρi实现各子结构间的调节,建立稳定的分散控制格式。在控制算法中采用了准滑模控制方法,克服变结构滑动模态中的抖振影响。利用本文方法,对20层钢结构基准模型在地震激励下的控制进行设计并数值仿真,验证了该方法的有效性。  相似文献   

5.
In the previous work of Huang et al., a coordinated decentralized hybrid adaptive output feedback fuzzy control scheme of large-scale nonlinear systems is obtained predicated upon this prerequisite assumption that the local controllers can share the a priori information about their individual reference models. In this note, we concentrate in the absence of the coordination assumption on developing a classical decentralized combined indirect and direct adaptive fuzzy controller for a class of uncertain large-scale nonlinear systems. The output feedback and adaptation mechanisms proposed for each subsystem hinges just upon its individual output, regardless of any other output reference. Neither the famous strictly positive real (SPR) condition nor a high-gain observer (HGO) is required to realize the overall output feedback algorithm. The tracking errors of the closed-loop large-scale system are shown to converge to tunable neighborhoods of the origin. Simulation results on correlated inverted pendulums verify the validity of the decentralized controller modification.  相似文献   

6.
In this paper, the decentralized stabilization control approach based on the dynamic surface control (DSC) is proposed for a class of large-scale interconnected stochastic nonlinear systems. The proposed approach combined the existing dynamic surface control (DSC) with back-stepping technique. This approach can overcome the problem of “explosion of complexity” inherent in the back-stepping method. Thus, the proposed control approach is simpler than the traditional back-stepping control method for the large-scale interconnected stochastic nonlinear systems. The stability analysis shows that all the signals in the closed-loop system are uniformly ultimately bounded (UUB). Finally, an example is provided to illustrate the effectiveness of the proposed control system.  相似文献   

7.
Algorithms for solving the problem of design of static output feedback controllers for stationary linear systems with continuous and discrete time are reviewed. The inverse problem is considered. The algorithms of synthesis of output feedback controllers are generalized to the case of a periodic discrete-time system. To solve such problems, it might be more natural to use an approach based on multi-criterion optimization. It is also shown that these algorithms can be used for the optimal stabilization of unstable systems with delay. In this connection, the parameters of a controller with given structure for a controlled unstable scalar system with delay are optimized. To this end, the system is first approximated by a system without delay, with the exponent approximated by a fractionally rational function. Since the structure of the controller is given, the quality of approximation is estimated as the difference (in the space of controller coefficients) between the stability domains of the original and approximating systems. At the next stage, the gain coefficients of the controller for the reduced system are optimized. The efficiency of the thus synthesized controller is assessed through mathematical modeling of a system with delay whose feedback loop is defined by the gain coefficients found. The approach is illustrated by stabilizing an inverted simple pendulum with a proportional–derivative controller with delay. The problem of synthesis of a robust controller for this example is considered. Some examples of designing a robust controller, including for a third-order system in which the delay rather than some parameter is uncertain are presented  相似文献   

8.
Several control schemes have been proposed for stabilization of artificial quadruped locomotion systems, but attainment of adequate stability is still one of the barriers in designing a legged vehicle. A combination of continuous and discrete state feedback seems to provide a good way to maintain stable motion of such a system. In this paper, side step control, which is a discrete feedback technique, is studied by means of a linearized locomotion system. The results are verified by application to a nonlinear quadruped vehicle simulation.  相似文献   

9.
The (mixed finite element) discretization of the linearized Navier–Stokes equations leads to a linear system of equations of saddle point type. The iterative solution of this linear system requires the construction of suitable preconditioners, especially in the case of high Reynolds numbers. In the past, a stabilizing approach has been suggested which does not change the exact solution but influences the accuracy of the discrete solution as well as the effectiveness of iterative solvers. This stabilization technique can be performed on the continuous side before the discretization, where it is known as ‘grad‐div’ (GD) stabilization, as well as on the discrete side where it is known as an ‘augmented Lagrangian’ (AL) technique (and does not change the discrete solution). In this paper, we study the applicability of ??‐LU factorizations to solve the arising subproblems in the different variants of stabilized saddle point systems. We consider both the saddle point systems that arise from the stabilization in the continuous as well as on the discrete setting. Recently, a modified AL preconditioner has been proposed for the system resulting from the discrete stabilization. We provide a straightforward generalization of this approach to the GD stabilization. We conclude the paper with numerical tests for a variety of problems to illustrate the behavior of the considered preconditioners as well as the suitability of ??‐LU factorization in the preconditioners. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

10.
针对执行器发生部分失效故障的漂浮基空间机器人系统,提出了一种自适应H分散容错控制算法。利用拉格朗日第二类方程建立了系统的动力学模型。根据分散原理将系统分解为以基座或臂杆为单元的多个子系统,并将表示执行器控制能力的有效因子融入到每个子系统,使得单个子系统的执行器故障不会影响相邻执行器的正常运行。通过对每个故障子系统设计形式一致的自适应容错算法实现对整个系统的容错控制。仿真结果表明,与现有某非奇异终端滑模容错算法相比,本文算法具有更快的跟踪速度和更高的跟踪精度。  相似文献   

11.
多工况应力和位移约束下连续体结构拓扑优化   总被引:42,自引:3,他引:39  
隋允康  杨德庆  王备 《力学学报》2000,32(2):171-179
将文「1」所提出的对拓扑变量的独立连续映射(IGM)的拓扑估化方法应用于连续体结构,从而建立了统一的以重量为目标,考虑应力和位移约束的连续体结构拓扑优化模型。通过对位移-应力拓扑解和各工况下应力拓扑解的综合协调,进而对于协调拓扑解按照阈值完成从离散到连续的反演,并且采用分层与加权策略克服了“荷载病态”困难。给出的经典的二维平面问题和三维连续体结构拓扑优化算例表明,这种统一的模型由骨架结构发展到连续  相似文献   

12.
IntroductionInrecentyears,decentralizedstabilizationoflarge_scaleinterconnectedsystemshasbeenwidelystudied .LeeandRadovic[1,2 ]establishedsomedecentralizedstabilizationconditionsforlarge_scalelinearcontinuousanddiscretetime_delay .Inthismethod ,morestructu…  相似文献   

13.
Negatively invariant compact sets of autonomous and nonautonomous dynamical systems on a metric space, the latter formulated in terms of processes, are shown to contain a strictly invariant set and hence entire solutions. For completeness the positively invariant case is also considered. Both discrete and continuous time systems are considered. In the nonautonomous case, the various types of invariant sets are in fact families of subsets of the state space that are mapped onto each other by the process. A simple example shows the usefulness of the result for showing the occurrence of a bifurcation in a nonautonomous system.  相似文献   

14.
The theory of time scales, which unifies continuous and discrete analysis, provides a powerful mathematical tool for the study of complex dynamic systems. It enables us to understand more clearly the essential problems of continuous systems and discrete systems as well as other complex systems. In this paper, the theory of generalized canonical transformation for second-order Birkhoffian systems on time scales is proposed and studied, which extends the canonical transformation theory of Hamilton canonical equations. First, the condition of generalized canonical transformation for the second-order Birkhoffian system on time scales is established.Second, based on this condition, six basic forms of generalized canonical transformation for the second-order Birkhoffian system on time scales are given. Also, the relationships between new variables and old variables for each of these cases are derived. In the end, an example is given to show the application of the results.  相似文献   

15.
This paper presents some novel discussions on fully decentralized and semi-decentralized control of fractional-order large-scale nonlinear systems with two distinctive fractional derivative dynamics. First, two decentralized fractional-order sliding mode controllers with different sliding surfaces are designed. Stability of the closed-loop systems is attained under the assumption that the uncertainties and interconnections among the subsystems are bounded, and the upper bound is known. However, determining the interconnections and uncertainties bound in a large-scale system is troublesome. Therefore in the second step, two different fuzzy systems with adaptive tuning structures are utilized to approximate the interconnections and uncertainties. Since the fuzzy system uses the adjacent subsystem variables as its own input, this strategy is known as semi-decentralized fractional-order sliding mode control. For both fully decentralized and semi-decentralized control schemes, the stability of closed-loop systems has been analyzed depend on the sliding surface dynamics by integer-order or fractional-order stability theorems. Eventually, simulation results are presented to illustrate the effectiveness of the suggested robust controllers.  相似文献   

16.
The basic concepts about the active structures and some attributes of the modes were presented in paper "Liner Active Structures and Modes ( Ⅰ ) ". The characteristics of the active discrete systems and active beams were discussed, especially, the stability of the active structures and the orthogonality of the eigenvectors. The notes about modes were portrayed by a model of a seven-storeyed building with sensors and actuators. The concept of the adjoint active structure was extended from the discrete systems to the beams that were the representations of the continuous structures. Two types of beams with different placements of the measuring and actuating systems were discussed in detail. One is the beam with the discrete sensors and actuators, and the other is the beam with distributed sensor and actuator function. The orthogonality conditions were derived with the modal shapes of the active beam and its adjoint active beam. An example shows that the variation of eigenvalues with feedback amplitude for the homo-configuration and non-homo-configuration active structures.  相似文献   

17.
We study the well-posedness of coagulation-fragmentation models with diffusion for large systems of particles. The continuous and the discrete case are considered simultaneously. In the discrete situation we are concerned with a countable system of coupled reaction-diffusion equations, whereas the continuous case amounts to an uncountable system of such equations. These problems can be handled by interpreting them as abstract vector-valued parabolic evolution equations, where the dependent variables take values in infinite-dimensional Banach spaces. Given suitable assumptions, we prove existence and uniqueness in the class of volume preserving solutions. We also derive sufficient conditions for global existence. Accepted: (August 18, 1999)  相似文献   

18.
This paper evolved from an endeavor to construct a Lyapunov function of interconnected nonlinear systems described by ordinary differential equations. This construction is an intractable problem and crucial part of the design when applied to problems of high dimension with intricate structure. The design obtained is applicable if the system under investigation is a generalization of the strict feedback form and whose dependency graphs satisfies the decomposition into lower triangular form. This design is mainly developed for moderated nonlinear continuous time dynamical systems. However, as we show in the example, it is emphasized that the present results can be extended to discontinuous systems provided they can be approximated by smooth modifications. A key step in our approach which based on back integrating procedure is to decompose the interconnected system into subsystems using graph theoretic decomposition. In the proposed methodology, the postulated Lyapunov function is obtained by backward integration the composite system trajectory. This novel approach leads straightforward and by one shot methods to both Lyapunov function of the composite system and its time derivative. A practical example is presented to illustrate the effectiveness of the results.  相似文献   

19.
多跨梁离散系统的频谱和模态的定性性质   总被引:1,自引:0,他引:1  
采用差分法建立了两端任意支承多跨梁的差分离散模型,对只具有两端支 承的单跨梁是正系统的情形,导出了对应的多跨梁差分离散系统的柔度系数;从单跨梁正 系统的刚度矩阵的符号振荡性出发,通过引入辅助系统,讨论了多跨梁的柔度矩阵的振荡 性,确定了对应于单跨梁正系统的多跨梁差分离散系统的频谱和模态的一系列定性性质.  相似文献   

20.
We apply steady-state capillary-controlled upscaling in heterogeneous environments. A phase may fail to form a connected path across a given domain at capillary equilibrium. Moreover, even if a continuous saturation path exists, some regions of the domain may produce disconnected clusters that do not contribute to the overall connectivity of the system. In such cases, conventional upscaling processes might not be accurate since identification and removal of these isolated clusters are extremely important to the global connectivity of the system and the stability of the numerical solvers. In this study, we address the impact of percolation during capillary-controlled displacements in heterogeneous porous media and present a comprehensive investigation using random absolute permeability fields, for water-wet, oil-wet and mixed-wet systems, where J-function scaling is used to relate capillary pressure, porosity and absolute permeabilities in each grid cell. Important information is revealed about the average connectivity of the phases and trapping at the Darcy scale due to capillary forces. We show that in oil-wet and mixed-wet media, large-scale trapping of oil controlled by variations in local capillary pressure may be more significant than the local trapping, controlled by pore-scale displacement.  相似文献   

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