Control and Communication Challenges in Networked Real-Time Systems

A current survey of the emerging field of networked control systems is provided. The aim is to introduce the fundamental issues involved in designing successful networked control systems, to provide a snapshot assessment of the current state of research in the field, to suggest useful future research directions, and to provide a broad perspective on recent fundamental results. Reflecting the goals of the Special Issue itself, this paper surveys relevant work from the areas of systems and control, signal processing, detection and estimation, data fusion, and distributed systems. We discuss appropriate network architectures, topics such as coding for robustly stable control in the presence of time-varying channel capacity, channels with fixed versus adaptively variable data width, issues in data rate problems in nonlinear feedback problems, and problems in routing for stability and performance. In surveying current research on networked control systems, we find that recent theoretical advances and target applications are intimately intertwined. The common goal of papers in the Special Issue which follows is to describe key aspects of this relationship. We also aim to provide a bridge between networked control systems and closely related contemporary work dealing with sensor networks and wireless communication protocols     

Guest Editorial Special Section on Real-Time and (Networked) Embedded Systems

The 11 papers in this special section focus on real-time and (networked) embedded systems. The section is divided into three groups. The first group contains papers dealing with scheduling, optimization, and analysis of embedded real-time systems. The second deals with the integration of components into distributed systems, analyzing aspects related to composition, and quality-of-service. The last group of papers investigates the problems related to real-time networks, in both wired and wireless environments.     

Guest Editorial: Networking, Sensing, and Control for Networked Control Systems: Architectures, Algorithms, and Applications

The eight papers in this special issue focus on networking, sensing, and control for networked control systems (NCS). The papers, which are briefly summarized, examine the architectures, algorithms and applications of NCS.     

Gain scheduler middleware: a methodology to enable existing controllers for networked control and teleoperation - part I: networked control

Conventionally, in order to control an application over a data network, a specific networked control or teleoperation algorithm to compensate network delay effects is usually required for controller design. Therefore, an existing controller has to be redesigned or replaced by a new controller system. This replacement process is usually costly, inconvenient, and time consuming. In this paper, a novel methodology to enable existing controllers for networked control and teleoperation by middleware is introduced. The proposed methodology uses middleware to modify the output of an existing controller based on a gain scheduling algorithm with respect to the current network traffic conditions. Since the existing controller can still be utilized, this approach could save much time and investment cost. Two examples of the middleware applied for networked control and teleoperation with IP network delays are given in these two companion papers. Part I of these two companion papers introduces the concept of the proposed middleware approach. Formulation, delay modeling, and optimal gain finding based on a cost function for a case study on DC motor speed control with a proportional-integral (PI) controller are also described. Simulation results of the PI controller shows that, with the existence of IP network delays, the middleware can effectively maintain the networked control system performance and stabilize the system. Part II of this paper will cover the use of the proposed middleware concept for a mobile robot teleoperation.     

Design and Stability Criteria of Networked Predictive Control Systems With Random Network Delay in the Feedback Channel

This paper is concerned with the design of networked control systems (NCSs) with random network delay in the feedback channel and gives stability criteria of closed-loop networked predictive control systems. The principle of predictive control is adopted to overcome the effects of network time delay. The necessary and sufficient conditions on the stability of the closed-loop NCS are derived, which provides useful analytical stability criteria. The closed-loop networked predictive control system with bounded random network delay is stable if the corresponding switched system is stable. Simulation and real-time results give an illustration of the proposed control strategies     

Guest Editorial Introduction to the Focused Section on Advanced Integrated Mechatronics

The 11 regular papers and four short papers in this special section focus on the research issues of advanced integrated mechatronics. The topics include advanced mechatronic sensing, devices and control, biomechatronics for better life, intelligent mechatronic systems, infotronics-enabled mechatronics systems, intelligent automation systems, and innovative applications of mechatronic systems.     

Context-Aware Security Solutions for Cyber-Physical Systems

The integration of physical systems and processes with networked computing has led to the emergence of a new generation of engineered systems, called Cyber-Physical Systems (CPS). These systems are large networked systems of systems, in which a component system may itself be a grid. In this paper we survey the current state of the art of CPS security, identify the issues surrounding secure control, and investigate the extent to which context information may be used to improve security and survivability of CPS.     

Consensus and Cooperation in Networked Multi-Agent Systems

This paper provides a theoretical framework for analysis of consensus algorithms for multi-agent networked systems with an emphasis on the role of directed information flow, robustness to changes in network topology due to link/node failures, time-delays, and performance guarantees. An overview of basic concepts of information consensus in networks and methods of convergence and performance analysis for the algorithms are provided. Our analysis framework is based on tools from matrix theory, algebraic graph theory, and control theory. We discuss the connections between consensus problems in networked dynamic systems and diverse applications including synchronization of coupled oscillators, flocking, formation control, fast consensus in small-world networks, Markov processes and gossip-based algorithms, load balancing in networks, rendezvous in space, distributed sensor fusion in sensor networks, and belief propagation. We establish direct connections between spectral and structural properties of complex networks and the speed of information diffusion of consensus algorithms. A brief introduction is provided on networked systems with nonlocal information flow that are considerably faster than distributed systems with lattice-type nearest neighbor interactions. Simulation results are presented that demonstrate the role of small-world effects on the speed of consensus algorithms and cooperative control of multivehicle formations     

New Predictive Control Scheme for Networked Control Systems

This paper is concerned with the design of networked control systems with random network-induced delay and data dropout. It presents a new control scheme, which is termed networked predictive control with optimal estimation. Based on Multirate Kalman Filtering, the measured data which are out of sequence or delayed can be used to improve the precision of estimation. The control prediction generator provides a set of future control predictions to make the closed-loop system achieve the desired control performance and the compensator removes the effects of the network transmission with time delay and data dropout. Simulation results are presented to illustrate the effectiveness of the control strategy via comparing with control schemes without any compensation for the network.     

Robust \mathcal{H}_{\infty} State Feedback Control of Networked Control Systems with Congestion Control

This paper examines the problem of robust state feedback control of networked control systems with a simple congestion control scheme. This simple congestion control scheme is based on comparing current measurements with last transmitted measurements. If their difference is less than a prescribed percentage of the current measurements then no measurement is transmitted to the controller. The controller always uses the last transmitted measurements to control the system. With this simple congestion control scheme, a robust $\mathcal {H}_{\infty}$ state feedback controller design methodology is developed based on the Lyapunov–Krasovskii functional approach. Sufficient conditions for the existence of delay mode dependent controllers are given in terms of bilinear matrix inequalities (BMIs). These BMIs are converted into quasi-convex linear matrix inequalities (LMIs) and solved by using the cone complementarity linearization algorithm. The effectiveness of the simple congestion control in terms of reducing the network bandwidth is elaborated using simulation examples.     

Ubiquitous communications - [Message from the Editor-in-Chief]

This issue includes two special topic sections. The first special topic section focuses on "Dependability Issues with Ubiquitous Wireless Access" and consists of five papers. The section looks at the factors affecting the dependability of wireless access for Internet services. The second special topic section is entitled "Recent Advances and Evolution of WLAN and WMAN Standards" and also includes five papers. The section looks from a different viewpoint at the issue of ubiquitous communications by considering the progress in IEEE data communications standards.     

智能网联汽车网络系统的研究

随着汽车的电动化、智能化和网联化,智能网联汽车已经成为汽车转型的重要发展方向之一。智能网联汽车上的电控系统、传感器等电子元件和系统的数量更多,这要求各系统之间的通信更加安全、迅速、准确,因此智能网联汽车必定是一个庞大的网络系统。文中从智能网联汽车网络的类型和特点、车载自组织网络以及车载移动互联网等方面,介绍了智能网联汽车的网络系统。     

NCS中的信息安全求解策略

网络控制是计算机、通信与控制技术结合发展的必然产物，具有开放性特征的网络控制系统面临着控制信息安全问题。针对网络控制系统的典型体系结构和信息安全需求，提出了基于分层思想和资源匹配的网络控制系统信息安全求解策略。     

多领航者网络化系统的动态群集运动

针对时变动态切换拓扑下具有多个领航者的网络化系统群集运动问题,本文分别给出了一阶／二阶网络化系统的控制算法,并对所提出的控制算法进行了理论分析。运用现代控制理论、代数图论和矩阵论等分析工具,研究了当通信拓扑为动态联合连通时,系统可以实现群集运动,即系统的运动轨迹都收敛到由多个领航者构成的凸包中。通过对系统信息拓扑连通部分的进一步研究,得到了二阶网络化系统群集运动的约束条件。最后应用仿真实验验证了结论的正确性。     

Special Section on Vehicular Energy-Storage Systems

The ten papers in this special section focus on state-of-the-art research and development and future trends in the modeling, design, control, and optimization of energy-storage systems for electric vehicles (EVs), hybrid electric vehicles (HEVs), fuel cell vehicles, and plug-in HEVs.     

具有时延和丢包的不确定性NCS的稳定性

研究了同时具有网络时延和数据丢包的不确定网络化控制系统的稳定性.将数据丢失看成一种特殊的时延,利用动态反馈控制器设计提高系统的动态性能,得到了总时滞(包括传感器与控制器之间的时滞,控制器与执行器之间的时滞)的表达式,建立了不确定网络化控制系统模型.通过构造李亚普诺夫函数,采用线性矩阵不等式技巧,给出了系统稳定的判定定理.仿真结果表明了该方法的有效性.     

网络视频监控业务在银行业的应用分析

银行业是视频监控应用的一个主要行业.2004年以前,国内绝大部分银行的监控系统以营业网点、金库、24小时自助银行等本地监控管理为主,与报警系统和门禁系统各自独立.随着国内银行金库被盗、暴力抢劫自助银行和离行式ATM机等多起事件的发生,包括视频监控系统在内的安防系统联网建设逐渐被银行高层纳入议事日程,网络视频监控逐渐成为银行监控应用的主要方式.本文介绍了银行安防系统的组成,着重分析了银行联网监控系统的架构,各监控场景的需求以及典型的案例.     

Guest editorial. Common channel signaling networks: performance,engineering protocols, and capacity management

An introductory article covers SS7 protocol, services, reliability, performance, and congestion control. Following the introductory article, the papers are arranged in three sections. The largest section is on performance analysis and congestion control. The papers in the second section address several issues relevant to the network level, including the impact of new services. The last section of this issue contains papers that highlight technical issues for future studies. This section carries a dual purpose: to introduce the preliminary results achieved by the authors and to suggest directions for additional work in this area     

Gain adaptation of networked DC motor controllers based on QoS variations

Connecting a complex control system with various sensors, actuators, and controllers as a networked control system by a shared data network can effectively reduce complicated wiring connections. This system is also easy to install and maintain. The trend is to use networked control systems for time-sensitive applications, such as remote DC motor actuation control. The performance of a networked control system can be improved if the network can guarantee quality-of-service (QoS). Due to time-varying network traffic demands and disturbances, QoS requirements provided by a network may change. In this case, a network has to reallocate its resources and may not be able to provide QoS requirements to a networked control application as needed. Therefore, the application may have to gracefully degrade its performance and perform the task as best as possible with the provided network QoS. This paper proposes a novel approach for networked DC motor control systems using controller gain adaptation to compensate for the changes in QoS requirements. Numerical and experimental simulations, and prototyping, are presented to demonstrate the feasibility of the proposed adaptation scheme to handle network QoS variation in a control loop. The effective results show the promising future of the use of gain adaptation in networked control applications.     

Bibliography on adaptive control systems

This bibliography contains the references to the major papers and reports on adaptive systems. The refmences listed are divided into two main sections, one for books and the other for journal, papers, reports, dissertations, patents, and conference papers. In the second section, papers, reports, etc., are indexed into categories e.g., applications, model reference systems, self-oscillating systems, etc.