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This paper is concerned with disturbance rejection control for a vibrating flexible string system in the presence of unknown disturbances. First, the boundary disturbance observer is proposed to deal with the boundary disturbance and the infinite dimensional disturbance observer is introduced to mitigate the effects of the distributed disturbance. Subsequently, the boundary control and distributed control are developed to suppress the vibration and globally stabilize the string system at its equilibrium position. Under the control proposed, the uniformly bounded stability of the controlled system is testified employing rigorous analysis without resorting to discretization of the partial differential equation dynamics depending on the time and space. Finally, the simulation and comparison results verify the performance of the derived control. 相似文献
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In this study, we focus on the boundary control problem for a vibrating string system with saturated input under the condition of external disturbances. Based on the backstepping approach, a boundary vibration control scheme is proposed to globally stabilize the string around the equilibrium position. A smooth hyperbolic tangent function is exploited to restrict the control input, an auxiliary system and a Nussbaum function are adopted to cope with the nonlinear term derived from the input saturation, and a disturbance observer is employed to tackle the boundary disturbance. The developed controller can assure the convergence of the closed‐loop system state to a small neighbourhood of zero. By the appropriate choice of control design parameters, numerical simulation is conducted to show the effectiveness of the derived control. 相似文献
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ABSTRACTRecently, the problem of designing boundary controllers and observers for unstable linear constant-coefficient reaction–diffusion equation on N-balls has been solved by means of the backstepping method. However, the extension of these results to spatially varying coefficients is far from trivial. This work deals with radially varying reaction coefficients under revolution symmetry conditions on a sphere (the three-dimensional case). Under these conditions, the equations become singular in the radius. When applying the backstepping method, a similar type of singularity appears in the backstepping control and observer kernel equations. However, with a simple scaling transformation, we are able to reduce the singular equation to a regular equation, which turns out to be the same kernel equations appearing when using the one-dimensional backstepping method. In addition, the scaling transformation allows us to prove stability in the H 1 space. 相似文献
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In this paper, the state convergence problem for closed quantum systems is investigated. We consider two degenerate cases, where the internal Hamiltonian of the system is not strongly regular or the linearized system around the target state is not controllable. Both the cases are closely related to practical systems such as one‐dimensional oscillators and coupled two spin systems. An implicit Lyapunov‐based control strategy is adopted for the convergence analysis. In particular, two kinds of Lyapunov functions are defined by implicit functions and their existences are guaranteed by a fixed point theorem. The convergence analysis is investigated by the LaSalle invariance principle for both cases. Moreover, the two Lyapunov functions are unified in a general form, and the characterization of the largest invariant set is presented. Finally, simulation studies are included to show the effectiveness and advantage of the proposed methods. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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随着化石能源的日渐枯竭,海洋热能转换系统（Ocean thermal energy conversion,OTEC）是可以利用海水间的温差将清洁、可再生的海洋能转换为电能的能源系统,关于该系统的研究已引起了越来越多的关注与研究.在工作过程中,浮式海浪温差发电系统中用于传输深层低温海水的管道会受到外界环境的影响产生振动,而这些振动会直接影响系统的性能.本文将研究该柔性系统的振动控制问题,首先,建立用一个偏微分方程和一组常微分方程组成的模型来描述OTEC系统的动力学特性,并直接基于系统的动力学模型设计主动的边界控制器以及边界扰动观测器,从而消除外界扰动的影响,以及减少OTEC系统中柔性管道的横向形变,抑制系统的振动.此外,本文还考虑了OTEC系统中存在的输出约束问题,并且在所设计边界控制律的作用下,从理论上证明OTEC系统的稳定性,保证OTEC系统中的柔性管道的形变量最终收敛于平衡点附近以及浮式平台固定在初始位置附近.最后,通过选择合适的控制参数来对OTEC系统进行数字仿真,利用所得到的仿真结果验证了所设计控制律的有效性. 相似文献
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This paper studies a distributed optimal consensus problem for multiple double integrators under bounded velocity and acceleration. Assigned with an individual and private convex cost which is dependent on the position, each agent needs to achieve consensus at the optimum of the aggregate cost under bounded velocity and acceleration. Based on relative positions and velocities to neighbor agents, we design a distributed control law by including the integration feedback of position and velocity errors. By employing quadratic Lyapunov functions, we solve the optimal consensus problem of double-integrators when the fixed topology is strongly connected and weight-balanced. Furthermore, if an initial estimate of the optimum can be known, then control gains can be properly selected to achieve an exponentially fast convergence under bounded velocity and acceleration. The result still holds when the relative velocity is not available, and we also discuss an extension for heterogeneous Euler-Lagrange systems by inverse dynamics control. A numeric example is provided to illustrate the result. 相似文献
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研究了线性扩张状态观测器(Extended state observer, ESO)的估计能力,并且分析了在线性自抗扰控制(Linear active disturbance rejection control, LADRC)下闭环系统的稳定性. 对于系统模型未知的情形, 给出了线性扩张观测器估计误差有界的证明, 并通过分析得出了如下结论: 在扩张状态观测器跟踪误差趋于零的前提下, 在线性自抗扰控制下的闭环系统可以实现对设定信号的精确跟踪以及输入-输出有界(Bounded input and bounded output, BIBO)稳定. 相似文献
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State estimation is an important problem in distributed parameter system especially with nonlinear dynamics in industrial process. An extended Luenberger observer based on the eigen-spectrum of the system operator is developed in this paper to handle this problem. The distributed parameter system is projected into a finite-dimensional subspace where a low-order ordinary differential equation describing the dominant dynamics of the system is derived. A Luenberger observer extended with a nonlinear part is developed based on that dominant dynamics. A sufficient condition is given in this paper for the convergence of the estimated error. Finally, by applying the developed design method to the temperature estimation of a catalytic rod, the achieved simulation results show the effectiveness of the proposed observer. 相似文献
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A static Luenberger observer of a system with Sturm–Liouville operator is synthesised with the aid of a boundary control formulation. To this aim, approximate observability, detectability and stability of the system is studied and design results are worked out for a typical biochemical case study. 相似文献
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In this paper, the state transfer of finite dimensional closed quantum systems with dipole and polarizability coupling in non‐ideal cases is investigated. Two kinds of non‐ideal systems are considered, where the internal Hamiltonian of the system is not strongly regular and not all the eigenvectors of the internal Hamiltonian are directly coupled with the target state. Such systems often exist in practical quantum systems such as the one‐dimensional oscillator and coupled two‐spin system. An implicit Lyapunov‐based control strategy is proposed here with convergence analysis for quantum systems modeled by finite dimensional bilinear Schrödinger equations. Specifically, two kinds of Lyapunov functions are defined via implicit functions, and their existences are guaranteed with the help of a fixed point theorem. Then, the local convergence analysis is investigated with the explicit characterization of the largest invariant set by LaSalle invariance principle. Finally, the performance of the feedback design is illustrated by numerical simulations. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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本文研究了具有未知边界扰动和分布扰动的柔性机械臂系统的边界控制. 为了补偿扰动和抑制柔性臂的振动, 针对利用Hamilton原理建立的无穷维偏微分方程模型, 设计了带有扰动观测器的鲁棒边界控制器对柔性臂进行控制. 利用Lyapunov方法对柔性臂系统的稳定性和一致有界性进行了证明. 所提出的控制方法所需测量信息较少, 对未知扰动具有鲁棒性, 并且所提出的边界控制策略能保证对柔性臂的振动抑制, 系统状态最终是外界扰动下指数稳定的. 最后, 通过数值仿真验证了所提出控制器对柔性臂振动抑制的有效性. 相似文献
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The output feedback robust model predictive control (MPC), for the linear parameter varying (LPV) system with norm-bounded disturbance, is addressed, where the model parametric matrices are only known to be bounded within a polytope. The previous techniques of norm-bounding technique, quadratic boundedness (QB), dynamic output feedback, and ellipsoid (true-state bound; TSB) refreshment formula for guaranteeing recursive feasibility, are fused into the newly proposed approaches. In the notion of QB, the full Lyapunov matrix is applied for the first time in this context. The single-step dynamic output feedback robust MPC, where the infinite-horizon control moves are parameterised as a dynamic output feedback law, is the main topic of this paper, while the multi-step method is also suggested. In order to strictly guarantee the physical constraints, the outer bound of the true state replaces the true state itself, so tightness of this bound has a major effect on the control performance. In order to tighten the TSB, a procedure for refreshing the real-time ellipsoid based on that of the last sampling instant is given. This paper is conclusive for the past results and far-reaching for the future researches. Two benchmark examples are given to show the effectiveness of the novel results. 相似文献
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针对同时含有未知输入和测量干扰的不确定系统研究了全维和降维观测器设计问题. 首先, 利用待定系数法给出了全维观测器的结构和存在条件. 该条件完全由原系统的系统矩阵给出, 易于检验. 对于降维观测器, 为了消除测量干扰的影响, 提出了一种新的测量输出构造方法, 使得新构造的测量输出不再包含干扰信号. 此外, 证明了全维和降维观测器存在条件的内在统一性, 即全维观测器所需要满足的观测器匹配条件和强可检测条件在研究降维观测器所要讨论的新的系统中都可以得到保持. 因而, 在全维观测器存在条件下, 也可以设计一个相应的降维观测器. 最后, 给出了一个数值例子验证所提方法的有效性. 相似文献
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为确保控制器输出在其允许的物理限制范围内和克服进料流速波动对期望浓度响应的影响,针对连续搅拌槽反应釜(CSTR)系统,采用了一种出口浓度控制和进料流速估计的算法,这种简单的控制策略考虑到作为输入变量的冷却剂流速的有界属性,借助自适应观测器得到进料流速和系统状态.由于考虑了进料流速波动的影响,所提策略对实际生产中由于设备... 相似文献
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针对一种欠驱动基准系统,具有旋转激励的平移振荡器(translation oscillators with rotating actuator,TORA)系统,本文首次提出了一种具有约束的控制方法.该方法不仅可以保证闭环系统的稳定性,而且能够保证旋转小球在预设的范围内转动.相比已有控制方法,本文所提方法可以预设小球的转动范围以避免不理想的\"循环\"行为.具体而言,首先对系统的总机械能进行了详细分析;随后在其总机械能的基础上通过能量整形构造出一个新颖的能量函数;最后基于所构造的能量函数提出了一种具有约束的控制器,采用Lyapunov方法及La Salle不变性原理证明了相应闭环系统的稳定性.通过与已有方法进行仿真对比可知,本文方法在镇定控制与约束控制方面均表现出良好的控制性能. 相似文献
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In this paper,the adaptive fuzzy tracking control is proposed for a class of multi-input and multioutput(MIMO)nonlinear systems in the presence of system uncertainties,unknown non-symmetric input saturation and external disturbances.Fuzzy logic systems(FLS)are used to approximate the system uncertainty of MIMO nonlinear systems.Then,the compound disturbance containing the approximation error and the timevarying external disturbance that cannot be directly measured are estimated via a disturbance observer.By appropriately choosing the gain matrix,the disturbance observer can approximate the compound disturbance well and the estimate error converges to a compact set.This control strategy is further extended to develop adaptive fuzzy tracking control for MIMO nonlinear systems by coping with practical issues in engineering applications,in particular unknown non-symmetric input saturation and control singularity.Within this setting,the disturbance observer technique is combined with the FLS approximation technique to compensate for the efects of unknown input saturation and control singularity.Lyapunov approach based analysis shows that semi-global uniform boundedness of the closed-loop signals is guaranteed under the proposed tracking control techniques.Numerical simulation results are presented to illustrate the efectiveness of the proposed tracking control schemes. 相似文献
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针对近空间飞行器姿态控制中出现的执行器故障,输入饱和与外部干扰等问题,设计了一种基于二阶滑模干扰观测器和辅助系统的鲁棒容错跟踪控制方法.首先,将系统不确定,外部扰动和执行器故障作为复合干扰,设计super-twisting二阶滑模干扰观测器对其进行估计.然后为解决输入饱和问题构造了辅助分析系统,并借助backstepping方法,设计姿态容错跟踪控制器.利用Lyapunov方法,严格证明了所有闭环系统信号的收敛性.最后将所设计的控制方法应用于近空间飞行器姿态控制中,仿真结果验证了该控制方法的有效性. 相似文献
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基于干扰观测器控制（Disturbance-observer-based control,DOBC）作为一种有效的干扰补偿策略取得了广泛的应用. 然而,当干扰和控制输入不能在同一时刻进入控制通道时,外部信号很难得到实时估计和补偿.提出一种复合DOBC结构,包括干扰观测、干扰预测和反馈调节三个部分.该方法的特点是即使一类非线性系统存在输入时滞,同样可以继承传统DOBC的优点. 最后,通过构造辅助观测器给出了预测误差以及复合闭环系统的稳定性分析方法. 相似文献