Decentralized control of multi-channel systems with direct control feedthrough

Linear, time-invariant, multi-channel, general proper systems with direct control feedthrough are considered. A polynomial matrix method is presented to derive explicit conditions characterizing the systems which can be made controllable or stabilizable through a single channel by applying non-dynamic decentralized feedback to all other channels. These conditions are then applied to the decen- tralized pole-assignment and stabilization problems for the systems, yielding a complete criterion for determining when the closed-loop spectrum can be freely assigned or stabilized with decentralized control. It can be expected that the results obtained will have direct application to periodic discrete-time control systems.     

时滞不确定组合系统的鲁棒分散输出控制

讨论了时滞不确定组合系统的鲁棒分散输出控制问题．不确定项存在于子系统内部，可以是非线性或时交的：而且时滞存在互联项中，并满足匹配条件．不确定项是有界的，但界是未知的．利用自适应律来估计未知的上界，设计出分散无记忆输出控制器．基于Lyapunov稳定性理论和Lyapunov-Krasovskii函数，该控制器能够保证闭环系统的解是终极一致有界的．最后的仿真结果说明该设计方法是有效的．     

Passivity-based decentralized stabilization of multi-agent systems with uncertainty and mixed delays

In this paper, we investigate a decentralized stabilization problem of uncertain multi-agent systems with mixed delays including discrete and distributed time-varying delays based on passivity stability. We design a decentralized state-feedback stabilization scheme such that the family of closed-loop feedback subsystems enjoys the delay-dependent passivity stability for each subsystem. Then, by employing a new Lyapunov-Krasovskii function, a linear matrix inequality （LMI） approach is developed to establish the delay-dependent criteria for the passivity stability of multi-agent systems. The sufficient condition is given for checking the passivity stability. The proposed LMI result is computationally efficient. An example is given to show the effectiveness of the method.     

一类扩展结构大系统的分散有限时间鲁棒关联镇定

研究一类扩展结构大系统分散有限时间鲁棒关联镇定问题. 扩展结构大系统是在原结构系统上增加新子系统而构成的, 在原系统分散控制律确定不变的情况下, 设计新加入子系统的鲁棒分散控制律, 使扩展后的系统仍能保持有限时间关联稳定. 利用LMI 方法推导此类系统基于状态反馈和输出反馈的分散有限时间关联镇定的充分条件, 并给出扩展子系统的相应控制器的设计方法. 最后通过仿真实验表明了所提出方法的可行性和有效性.

     

Decentralized adaptive output feedback design for large-scalenonlinear systems

In this paper, we present a global, decentralized adaptive design procedure for a class of large-scale nonlinear systems, which utilizes only local output feedback. The advocated scheme guarantees robustness to parametric and dynamic uncertainties in the interconnections and also rejects any bounded disturbances entering the system. The systems belonging to this class are those which can be transformed using a global diffeomorphism to the output feedback canonical form, where the interconnections are a function of subsystem outputs only. The uncertainties are assumed to be bounded by an unknown pth-order polynomial in the outputs. The resulting controller maintains global robustness and disturbance rejection properties. The output tracking error is shown to be bounded within a compact set, the size of which can be made arbitrarily small by appropriate choice of the control gains. For the case where the objective is regulation, global asymptotic regulation of all the states of the closed-loop system is achieved     

带有界扰动的一类大型互联非仿射非线性系统\=的鲁棒分散控制

对带有界扰动的一类大型互联非仿射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渐近稳定的;当扰动较小时,系统的状态能够收敛到原点的一个小邻域内．     

基于LMI的大型互联线性系统的分散有限时间镇定

借助于有限时间稳定性的定义,针对大型互联线性系统,引入了分散有限时间镇定的概念.对一类大型互联线性系统进行分散状态反馈和分散动态输出反馈控制器设计,利用线性矩阵不等式(LMI)的方法提出一个充分条件,当反馈控制律作用于该系统时,闭环系统是有限时间稳定的.仿真算例说明了所得结论的可行性和有效性.     

Decentralized control of linear multivariable systems

This paper studies the effect of decentralized feedback on the closed-loop properties of jointly controllable, jointly observablek-channel linear systems. Channel interactions within such systems are described by means of suitably defined directed graphs. The concept of a complete system is introduced. Complete systems prove to be precisely those systems which can be made both controllable and observable through a single channel by applying nondynamic decentralized feedback to all channels. Explicit conditions are derived for determining when the closed-loop spectrum of ak-channel linear system can be freely assigned or stabilized with decentralized control.     

一类时滞切换大系统的分散控制器设计

考虑一类常数时滞切换大系统的分散状态反馈控制器设计问题。在低维时滞子系统的单个子系统均不能被镇定的情况下,基于凸组合技术和线性矩阵不等式方法,设计出分散控制器和分散切换律,保证闭环系统渐近稳定。仿真结果表明所设计方法的可行性和有效性。     

互联大系统动态输出反馈多重叠鲁棒分散关联镇定

针对一类具有网型拓扑结构的互联大系统,提出一种动态输出反馈多重叠鲁棒分散关联镇定方法.该方法将系统状态空间加以扩展,在扩展空间中将其分解为按循环逆序排列的一系列两两子系统对,并为每个子系统对分别设计使其关联稳定的鲁棒分散动态输出反馈控制器,将这些多重叠设计的控制器再收缩回原空间,实现控制律的协调.将该方法应用到一个四区域网型电力系统控制设计中,仿真结果验证了所提出方法的可行性和优越性.     

Decentralized event-triggered control strategy in distributed networked systems with delays

Event-triggered control strategies have been recently proposed as alternatives to traditional time-triggered periodic sampling for feedback control systems. This paper studies the event-triggered control problem for distributed networked control systems (NCS). In order to reduce the network traffic and the resource of computation, we propose a new decentralized event-triggered scheme for the NCS, where a subsystem broadcast its state information to its neighbors only when the subsystem’s local state error exceeds a threshold with on-line adaption. The asymptotic stability of the resulting closed-loop system is guaranteed by the event-triggered feedback scheme. In addition, the paper gives the maximal allowable positive bounds on transmission delays for the networked control systems. Finally, the results are illustrated to be efficient by one simulated example.     

Exponential stabilization controller design for interconnected time delay systems

Decentralized robust control problem is investigated for a class of large scale systems with time varying delays. The considered systems have mismatches in time delay functions. A state coordinate transformation is first employed to change the original system into a cascade system. Then the virtual linear state feedback controller is developed to stabilize the first subsystem. Based on the virtual controller, a memoryless state feedback controller is constructed for the second subsystem. By choosing new Lyapunov Krasovskii functional, we show that the designed decentralized continuous adaptive controller makes the solutions of the closed-loop system exponentially convergent to a ball, which can be rendered arbitrary small by adjusting design parameters. Finally, a numerical example is given to show the feasibility and effectiveness of the proposed design techniques.     

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本文研究了用Lur'e多非线性系统描述的被控对象的镇定问题.把问题的可解性归结到特殊的多线性矩阵不等式的可解性.非线性状态反馈和输出反馈控制器的设计分别依赖于一个双线性和三个三线性矩阵不等式的解.给出了基于线性矩阵不等式的交替寻优算法的设计步骤.     

Decentralized adaptive stabilization in the presence of unknown backlash-like hysteresis

Due to the difficulty of handling both hysteresis and interactions between subsystems, there is still no result available on decentralized stabilization of unknown interconnected systems with hysteresis, even though the problem is practical and important. In this paper, we provide solutions to this challenging problem by proposing two new schemes to design decentralized output feedback adaptive controllers using backstepping approach. For each subsystem, a general transfer function with arbitrary relative degree is considered. The interactions between subsystems are allowed to satisfy a nonlinear bound with certain structural conditions. In the first scheme, no knowledge is assumed on the bounds of unknown system parameters. In case that the uncertain parameters are inside known compact sets, we propose an alternative scheme where a projection operation is employed in the adaptive laws. In both schemes, the effects of the hysteresis and the effects due to interactions are taken into consideration in devising local control laws. It is shown that the designed local adaptive controllers can ensure all the signals in the closed-loop system bounded. A root mean square type of bound is obtained for the system states as a function of design parameters. This implies that the transient system performance can be adjusted by choosing suitable design parameters. With Scheme II, the proposed control laws allow arbitrarily strong interactions provided their upper bounds are available. In the absence of hysteresis, perfect stabilization is ensured and the L₂ norm of the system states is also shown to be bounded by a function of design parameters when the second scheme is applied.     

Decentralized robust stabilization for large-scale feedforward non-linear systems

In this paper, we consider the decentralized robust stabilization problem for large-scale feedforward non-linear systems, which possess an upper-triangular structure, while in the decentralized control area the commonly studied large-scale feedback non-linear systems possess a lower-triangular structure. Our decentralized robust stabilizer for each subsystem takes a nested saturation feedback, with the saturation levels satisfying a set of equations and inequalities. Global asymptotic stability of the closed-loop large-scale system has been proved, and a simulation example is given.     

Decentralized stabilization of a class of interconnected stochasticnonlinear systems

This paper focuses on a class of large-scale interconnected stochastic nonlinear systems. The interconnections are bounded by strong nonlinear functions that contain first order and higher order polynomials as special cases. The problem we address is to design a decentralized controller such that the closed-loop, large-scale, interconnected stochastic nonlinear system is globally asymptotically stable in probability for all admissible interconnections. It is shown that the decentralized global stabilization via both state feedback and output feedback can be solved by a Lyapunov-based recursive design method     

导数反馈下闭环广义系统的稳定性

针对导数反馈下闭环广义系统的稳定性问题,利用一种受限等价意义下的矩阵束分解[5],首先给出在不同动态阶(从最小到最大阶)下消除脉冲行为的充分条件.并根据各种动态阶,分别给出导数反馈控制器的设计方法.进而给出导数反馈下闭环广义系统稳定及局部导数反馈下闭环广义关联大系统的分散稳定的充分条件.最后用数值算例来验证所给结果的有效性.     

Decentralized stabilization of large-scale feedforward systems using saturated delayed controls

This paper investigates the problem of decentralized stabilization via saturated delayed feedback. First, a new class of saturated delayed feedback controllers is proposed for a class of single-input feedforward nonlinear systems. Then, this design scheme is generalized for the setting of decentralized feedforward systems using saturated time-delayed feedback. The stability analysis for the closed-loop decentralized systems is rather simple based on the proposed feedback structure.     

Optimality of decentralized control for large-scale systems

A decentralized control scheme is given for the stabilization of large-scale linear systems composed of a number of controllable subsystems. A class of interconnection structures among subsystems is defined for which the overall system can always be stabilized by local state feedback which is optimal for a quadratic performance index. The resulting closed-loop system has robust stability properties against a wide range of variations in open-loop dynamics. Optimality of the decentralized control law is preserved for a modified performance index under perturbations in interconnections such that the strength of coupling does not increase. The class of decentrally stabilizable large-scale systems presented in this paper is the largest such class hitherto described by the structure of interconnections.     

不确定组合大系统的自适应分散镇定控制

考虑具有非线性关联作用的不确定时变线性组合大系统的自适应分散镇定问题.针对 系统不确定界完全未知的情形,首先从理论上证明了可设计自适应鲁棒分散控制器确保受控系 统渐近稳定;进而从工程实际应用的角度,给出了确保受控系统实用稳定的自适应鲁棒分散控 制器的设计方案.仿真说明该设计方案是有效的.