Decentralised sliding mode control for nonminimum phase interconnected systems based on a reduced-order compensator

In this paper, a class of interconnected systems with mismatched uncertainties is considered. A sliding surface is proposed in an augmented space formed by the system output and the compensator state variables, and the stability of the corresponding sliding mode is analysed. A robust decentralised reduced-order output feedback sliding mode controller is then designed to drive the system to the composite sliding surface and maintain a sliding motion on it thereafter. The proposed approach allows both the isolated nominal subsystem and the nominal interconnected system to be nonminimum phase. The known interconnections and the bounds on the uncertain interconnections are fully used in the control design to reduce conservatism.     

一类相似广义互联系统的导数-输出反馈鲁棒控制器设计

以广义系统中受限系统等价概念和导数反馈- 输出反馈为基础,定义了一类广义互联系统的相似结构,提出了相似性研究的新方向.这类系 统具有不满足匹配条件的非线性不确定互联项.设计了导数-输出反馈鲁棒分散控制器,使互 联系统在平衡点处渐近稳定.由于控制器本身也具有相似结构,因此易于工程实现.     

一类离散非线性不确定互联系统的模糊分散控制

利用模糊控制方法研究一类离散非线性互联系统的分散控制问题.首先采用模糊(T-S)模型对离散非线性不确定互联系统进行模糊建模,应用并行分布补偿算法(PDC)给出状态反馈分散模糊控制方案,并基于李亚普诺夫函数方法证明了闭环系统的稳定性.然后当系统的状态不完全可测时,设计模糊分散观测器来估计各子系统的状态,从而给出基于观测器的状态反馈分散模糊控制设计的方法.因为该分散模糊控制设计问题是以线性矩阵不等式的形式给出,所以很容易用凸优化方法求解.仿真结果验证了所提出控制方法的有效性.     

Decentralized robust controller design for a class ofinterconnected uncertain systems: with unknown bound of uncertainty

In this paper, a simple decentralized robust control scheme is proposed for a class of interconnected time-varying systems with uncertainties. The uncertainties may appear in the interconnections between the subsystems and also within the subsystems, and they are possibly nonlinear and time-varying. The uncertainties are bounded, but the bounds of the uncertainties are unknown in controller design. When certain matching conditions are satisfied for the uncertain interconnections and the uncertainties within the subsystems, the proposed decentralized control scheme guarantees the controlled system to converge exponentially with a prescribed degree toward the equilibrium of the system, or a residual ball around the equilibrium     

Decentralized variable-structure control design for uncertain large-scale systems with series nonlinearities

This paper presents a robust decentralized control for large-scale interconnected systems with series nonlinearities through variable-structure control. The proposed variable-structure control ensures the global reaching condition of the sliding mode of the composite system. The uncertain nonlinear system also possesses insensitivity to uncertainties and disturbances like a linear system does. Furthermore, the sliding mode can converge within a specified exponential speed.     

Decentralized dynamic output feedback controllers for interconnected systems with mismatched uncertainties using new sliding mode control

This paper presents a method for the design of decentralized output feedback controllers for an interconnected systems with mismatched uncertainties using a variable-structure control approach. A new reaching condition of the sliding mode is derived such that the reduced-order system is invariant to the mismatched uncertainties. In every subsystem, a new idea for a sliding mode that consists of two sets of switching surfaces is introduced, and a scheme of decentralized dynamic control using only output states is also proposed. This scheme can guarantee closed-loop stability of a sliding manifold of the composite system. Finally, a numerical example is given to illustrate the controller design method.     

跳变双线性随机离散组合系统的保成本分散控制

研究一类跳变双线性随机离散组合系统的保成本分散控制问题．首先给出问题可解的充分条件,然后基于线性矩阵不等式方法设计保成本分散状态反馈控制律．理想的保成本分散状态反馈控制器可通过应用现有的软件,求解一组线性矩阵不等式而得到．仿真例子说明了该方法的有效性.     

Decentralized global robust stabilization of a class of interconnected minimum-phase nonlinear systems

This paper focuses on a class of large-scale interconnected minimum-phase nonlinear systems with parameter uncertainty and nonlinear interconnections. The uncertain parameters are allowed to be time-varying and enter the systems nonlinearly. The interconnections are bounded by nonlinear functions of states. The problem we address is to design a decentralized robust controller such that the closed-loop large-scale interconnected nonlinear system is globally asymptotically stable for all admissible uncertain parameters and interconnections. It is shown that decentralized global robust stabilization of the system can be achieved using a control law obtained by a recursive design method together with an appropriate Lyapunov function.     

Decentralized sliding-mode output-feedback control of interconnected discrete-delay systems

Global decentralized discrete sliding mode control of a class of interconnected system using only output information is considered in this paper. Matched and unmatched uncertainties as well as known and unknown interconnections are treated. Bounded time-varying delays are considered within the subsystems and through interconnections. The stability of the reduced-order interconnected systems is analyzed using the Lyapunov–Kraszovskii approach and a novel reachability condition of the composite sliding surfaces is established. The resultant dynamics are proved to be globally asymptotically stable. Simulations show the efficacy of the proposed scheme.     

电液伺服系统的多滑模鲁棒自适应控制

针对一类参数与外负载非匹配不确定的非线性高阶系统,提出了一种基于逐步递推方法的多滑模鲁棒自适应控制策略.应用逐步递推的多滑模控制方法简化了高阶系统的控制问题,同时在自适应控制中加入鲁棒控制的方法,以消除不确定性对控制性能的影响.首先利用逐步递推方法与状态反馈精确线性化理论,得出确定系统的多滑模控制器设计方法;然后基于Lyapunov稳定性分析方法,给出不确定系统的参数自适应律,及鲁棒自适应控制器的设计方法.本文把该控制策略应用到电液伺服系统的位置跟踪控制中,仿真结果显示,该控制方法具有较强的鲁棒性及良好的跟踪效果.     

ROBUST DECENTRALIZED Hinfinity CONTROL FOR NONLINEAR INTERCONNECTED SYSTEMS WITH UNCERTAINTY

This paper focuses on the problem of robust decentralized Hinfinity control design for nonlinear interconnected systems with uncertainty. It presents, respectively, a state feedback control design and an output feedback control design, which will stabilize the plant and guarantee an Hinfinity-norm bound constraint on disturbance attenuation for all admissible uncertainties. The interconnection between the robust decentralized Hinfinity control problem and the nonlinear decentralized Hinfinity control for systems without uncertainty is established. Based on this interconnection, the solvable conditions of robust decentralized Hinfinity control is proposed in terms of Hamilton-Jacobi inequality.     

Robust adaptive control for interval time-delay systems

1 Introduction The problem of time-delay is commonly encountered in various engineering systems, such as electric, pneumatic and hydraulic networks, long transmission lines, etc., and it is also a great source of systems instability and poor perfor- mance. During the last decades, we have seen an increasing interest for the control of this class of systems and many results have reported in the literature [1～5]. On the other hand, it has been recognized that nonlinear uncertainties are unavoid…     

Decentralized global disturbance attenuation for a class of large-scale uncertain nonlinear systems

This paper studies the problem of global robust disturbance attenuation via decentralized state feedback for a class of large-scale nonlinear systems with parameter and interconnection uncertainties. The parameter uncertainty is from a compact set and the uncertain interconnections are bounded by higher-order polynomials of state variables. The problem that we address is to design a robust decentralized controller such that the closed-loop large-scale nonlinear system is input-to-state stable and the L₂ gain from the disturbance input to the controlled output is below a prescribed value for all admissible uncertain parameters and interconnections. A Lyapunov-based recursive design approach is developed to construct the decentralized controller explicitly. As a special case, the problem of almost disturbance decoupling via decentralized state feedback is also solved.     

数值界不确定性关联大系统分散鲁棒H∞控制

针对一类状态阵,控制输入阵及关联阵中存在数值界不确定性的关联大系统,研究其分散鲁棒H∞状态反馈和输出反馈控制器设计问题.基于有界实引理,推导出了其存在分散鲁棒H∞控制器的充分条件,即一组矩阵不等式有解.利用Schur补引理,通过固定不同变量,提出了一种构建分散控制器的同伦迭代线性矩阵不等式方法.所获得的控制器使闭环大系统鲁棒稳定,并且达到给定的H∞性能指标.最后用数值例子说明了所提的设计方法的有效性.     

一类不确定非线性大系统的分散鲁棒控制器设计

基于Backstepping方法，设计了一类具有不确定性扰动和不确定性关联项的非线性大系统的分散鲁棒稳定控制器。非线性大系统的关联项为时变有界非线性函数且不确定性扰动以仿射非线性方程的形式引入。为了提高系统的控制效果。将：Backstepping递推设计方法与L2增益控制相结合，所设计的分散鲁棒控制器不仅使每个子系统的状态向量跟踪一个指定的期望轨迹。而且还使系统的不确定性干扰具有L2增益控制。     

Decentralized discrete-time quasi-sliding mode control of uncertain linear interconnected systems

In this paper, a new global decentralized discrete-time quasi-sliding mode control of linear interconnected systems is presented. The proposed controller is free of chattering problem and can be applied to a broader class of large-scale systems. Additionally, it is capable to deal with both known and unknown interconnections among the subsystems. Stability of the reduced-order interconnected systems is analyzed using Lyapunov approach. The proposed decentralized controller guarantees the reachability of the connective sliding manifold. The resultant dynamics are proved to be globally asymptotically stable. Furthermore, the controller is made robust to external disturbances by employing a disturbance estimation scheme. The simulations are performed on model of a two-area power generation system and the results show the efficacy of the proposed scheme.     

滞后中立型关联控制系统的滑动模变结构控制*

本文设计了滞后中立型非线性关联系统的滑动曲面和分菜滑动模型控制器，每个子系统的控制器仅用到其局部状态信息，在滑动曲面和分散滑动模控制器可实现的条件下，在子上Ｒｉｃｃａｔｉ方程的描述和到了可实现滑动模控制器的一个充分条件，该条件等价于由分散和状态反馈镇定的条件，从而本文的结果比以前的工作更合适，且可实现减少设计的保守性。     

Decentralised robust sliding mode control for a class of nonlinear interconnected systems by static output feedback

In this paper, a class of nonlinear interconnected systems with nonlinear nominal subsystems is considered. Matched and mismatched uncertainties are both dealt with. Based on sliding mode techniques, a decentralised robust control scheme, using only output information, is presented to stabilise the system locally, but under certain circumstances, global results can be obtained. The approach allows a more general structure for the interconnections and uncertainty bounds than other literature in this area. The conservatism in the results is reduced by fully using system output information and the uncertainty bounds. A numerical example is used to demonstrate the efficacy of the method.     

含非匹配互联项的一类大型互联非线性系统的鲁棒分散控制

本文对带有界扰动的一类含非匹配互联项的大型互联非线性系统进行了分散状态反馈控制设计, 通过子系统状态的线性变换, 得到分散状态反馈控制律. 当状态反馈控制律作用于该系统时, 无扰动的闭环系统是全局渐近稳定的, 当扰动有界时, 系统的状态能够收敛到原点的一个与扰动的界相关的邻域内, 并给出仿真算例说明该结论的可行性和有效性.     

带有非线性不确定奇异系统的积分滑模控制

针对一类含有非线性不确定的奇异系统, 提出了一种面向性能的鲁棒控制器. 控制器由3部分组成: 积分滑模控制、附加的非线性控制及复合非线性反馈控制. 积分滑模控制可将匹配不确定完全抵消并使系统轨迹进入理想滑模; 附加的非线性控制用来抑制理想滑动模态上非匹配不确定对系统稳定性和性能的影响; 复合非线性反馈控制则保证闭环系统输出按性能要求渐近地跟踪参考输入信号. 最后通过算例说明所提算法的有效性.