布尔控制网络的能控性与能观性

利用矩阵的半张量积,布尔控制网络被转化为离散时间系统.本文从离散时间系统的结构矩阵出发,讨论了逻辑控制系统的能控能观性条件,得到了一个新的能控性条件.新的条件简化了原有能控性矩阵的计算复杂性,矩阵的最高阶数由原来的2m+n降到了2n.另外,还得到了检验布尔控制网络能观性的条件.与原有条件相比,新的条件更容易计算检验.最后,给出一个实例,检验给出的能控能观性判断条件的正确性.     

网络控制系统的能控性和能观性

给出了网络控制系统的定义，并基于线性时不变系统的被控对象，建立了传感器为时钟驱动，控制器和作动器为事件驱动时长时滞网络控制系统的数学模型，对网络控制系统的均值能控、均方能控、均值能观及均方能观作了定义，得到了网络控制系统能控的充分或必要条件及能观的充要条件．     

网络控制系统的能控性与能观性

针对随机时变时延的存在使得网络控制系统的分析变得非常复杂,传统的控制理论在应用到网络控制系统中时必须重新考虑的问题,通过在传感器和控制器的发送端和接收端引入缓冲器的方法,将网络控制系统中随机时延转化为确定性时延,在此基础上研究了网络控制系统的能控性和能观性,并给出了网络控制系统能控和能观的充分必要条件。该方法可推广至其他的时延系统中去。     

广义系统的能控、能观性判别条件

该文讨论广义系统能控、能观性问题,给出了广义系统能控和能观性一种新的判别条件.     

感应电动机系统的能控性与能观测性分析

分析了感应电动机系统的能控性与能观测性。结果表明系统是弱能控与弱能观的。而且,采用非线性状态反馈解耦控制和非线性坐标变换后的局部闭环解耦线性系统是能控与能观的。     

互联大系统能控能观性模型简化

不能控不能观系统可以集结成为一个能观但不能控的系统,这是传统的结论。本文提出一种旨在改变系统结构的新集结方法,可以把不能控和/或不能观系统集结成为具有相同输入输出关系且能控能观系统。并利用此结果对互联大系统进行分散能控能观性模型简化,并且给出若干重要理论结果和算法。     

一类混合动态系统的能控性和能观性研究

针对一类混合动态系统———周期型线性切换系统, 给出系统能控性、能观性的充分必要条件, 并通过例子加以验证.     

一类混合动态系统的能控性和能观性研究

针对一类混合动态系统--周期型线性切换系统,给出系统能控性、能观性的充分必要条件,并通过例子加以验证.     

线性切换系统的能控性与能达性*

本文针对一般线性切换系统,严格定义了系统的能控性、能达性和能控集、能达集,导出了能控性的一个必要条件,给出了三维单输入双切换系统能控性的充分必要条件,并指出现有文献中有关结论的一个错误.     

一类离散非方广义系统的能控性与能观性

本文针对一类离散非方广义系统模型,引入乘子得到其逆等矩阵模型,并进一步判断该类系统模型的完全能控性、能达能控性、完全能观性、能达能观性以及之间的对偶关系。     

Short-Period Communication and the Role of Zero-Order Holding in Networked Control Systems

We discuss controller design for a networked control system (NCS) in which a stochastic linear time invariant (LTI) plant communicates with a controller over a shared medium. The medium supports a limited number of simultaneous connections between the controller and the plant's sensors and actuators, possibly subject to transmission delays. We restrict communication to periodic medium access sequences which preserve the structural properties of the plant, thus decoupling the selection of the communication from that of the controller. Using the plant's controllability/observability indices as a guide for allocating access, we show that the period of the sequences in question can be shorter than previously established. In addition, we explore the use of sequences designed for a simple NCS model, in which sensors and actuators are “ignored” by the controller when they are not actively communicating, in a more complex, but practical, setting that includes zero-order holding. We include a numerical experiment that illustrates our results in the context of LQG control.      

Try-once-discard scheduling for stochastic networked control systems

In practical networked control systems (NCS), such as smart grids, cooperative robotics, and sensor networks, often multiple control applications share a communication infrastructure, requiring a smart and efficient scheduling mechanism to coordinate the access to the capacity-limited communication medium. In this article we consider the problem of event-based scheduling design for NCSs consisting of multiple control loops over a shared communication medium. We extend the notion of Try-Once-Discard (TOD), which is one of the basic deterministic event-based scheduling protocols for resource constrained NCSs, to the case of multiple stochastic control systems coupled via a shared communication medium subject to capacity limitation and stochastic packet delivery failure. Showing that the overall network-induced error is a homogeneous Markov chain in our stochastic set-up, we first study stability properties of such networked systems under the TOD scheduling scheme employing the concepts of stochastic stability. Then, we derive sufficient stability conditions under the TOD rule assuming that the communication channel is not ideal, i.e. a scheduled data packet for transmission might be lost in the communication channel with a non-zero probability. Furthermore, we derive analytic performance bounds by finding uniform upper-bounds for an average quadratic cost function. The numerical simulations are performed for variety of system parameters and NCS set-ups to strengthen our stability claim as well as illustrating performance bounds. Additionally, we show that the TOD scheduling rule outperforms the conventional time-triggered, and uniform and non-uniform random channel access arbitration mechanisms, in terms of efficient coordination of channel access in stochastic NCSs.     

路由协议测试的窗口黑盒模型和多通道的测试方法

路由协议测试中的效率和覆盖率亟待提高,原有通信协议测试理论将被测实现作为黑盒,使得大量可增强控制观察能力的手段无法利用,因此在路由协议测试中以窗口黑盒模型描述被测实现,在测试结构上实现了多通道测试方法,提高了测试效率和测试覆盖率,通过与被测模块交互的其它模块,增强了测试的控制观察能力,测试便的执行时间相比原有方式下降50％;消除或减小了以往不能测试的范围和内容,相应测试例个数增加3倍以上;为目前急需的大规模的路由器测试工作奠定了基础。     

Structural Properties,LQG Control and Scheduling of a Networked Control System with Bandwidth Limitations and Transmission Delays

The problem of simultaneous LQG control and scheduling of a Networked Control System (NCS) with constant network induced delays at input and output and bandwidth limitations is investigated. Delays are considered at plant as well as controller side. Sufficient conditions for controllability, stabilizability, reconstructibility and detectability of the underlying networked control system are drawn. The proposed conditions extend previous works on structural properties of NCS by capturing both plant and controller side delays together with bandwidth limitations. A framework for computing the optimal LQG controller for the NCS with a fixed scheduling is provided. The proposed modeling approach facilitates use of LQG as well as other control methods for NCSs with delays and bandwidth limitations. In order to optimize performance, a semi-online scheduling procedure is proposed based on an offline look up table. The look up table assigns an optimal schedule with associated optimal LQG controller to initial conditions. The proposed scheme improves previous results by online deployment of schedule and LQG control with stability guarantees and very low computational overhead. A simulation example with communication delays, packet losses and bandwidth limitations in both sensor and actuator sides is included. Static optimal periodic communication sequence, Optimal Pointer Placement (OPP) approach proposed in previous works, a random access scheduling method representing contention based access policies and the proposed method are simulated and compared.      

Communication and control co-design for networked control systems

This paper discusses the stabilization of a networked control system (NCS) in which sensors and actuators of a plant exchange information with a remote controller via a shared communication medium. Access to that medium is governed by a pair of periodic communication sequences. Under the model utilized here, the controller and plant handle communication disruptions by “ignoring” (in a sense to be made precise) sensors and actuators that are not actively communicating. This choice has the effect of significantly reducing the complexity of selecting control/communication policies. It is shown that, for discrete-time NCS, the reachability and observability of the plant can be preserved if the communication sequences are chosen properly. We propose a method for exponentially stabilizing a NCS by first identifying a pair of communication sequences that preserve reachability and observability and then designing an observer-based feedback controller based on those sequences.     

Stabilization of linear discrete‐time networked control systems via protocol and controller co‐design

This paper investigates the stabilization problem for networked control systems (NCSs) with communication constraint and packet loss. The communication constraint considered is that only one network node is allowed to access a shared communication channel during one time‐slot, and a feedback control is performed with only partially available measurements and control inputs. By taking random packet loss into consideration, a stochastic switched system model is presented to describe the NCS. A sufficient condition is derived for the NCS to be mean‐square exponentially stable, and it is shown that the system performance specified by the exponential decay rate critically depends on the network accessing rates (NARs) of the network nodes and the packet loss probability. The state feedback controller and scheduling protocol, which allocates the NARs, are co‐designed such that the NCS achieves a minimal decay rate. Finally, an illustrative example is given to show the effectiveness of the proposed design approach. Copyright © 2014 John Wiley & Sons, Ltd.     

Schedulability-Driven Communication Synthesis for Time Triggered Embedded Systems

We present an approach to static priority preemptive process scheduling for the synthesis of hard real-time distributed embedded systems where communication plays an important role. The communication model is based on a time-triggered protocol. We have developed an analysis for the communication delays with four different message scheduling policies over a time-triggered communication channel. Optimization strategies for the synthesis of communication are developed, and the four approaches to message scheduling are compared using extensive experiments.     

Linear time-variable systems: Balancing and model reduction

A "uniformly balanced" realization for linear time-variable systems is defined. This representation is characterized by the fact that its controllability, and observability Gramians are equal and diagonal. Existence and uniqueness of the uniformly balanced realization is studied. Such a framework has many remarkable properties and leads to a novel method for approximating time-variable systems, where the subsystems of the balanced realization can be taken as a reduced model. The reduced model is examined from the point of view of stability, controllability, and observability.