Control reconfiguration

About: Control reconfiguration is a research topic. Over the lifetime, 22423 publications have been published within this topic receiving 334217 citations.

Fault diagnosis and reconfiguration in flight control systems

Abstract: The problem of fault diagnosis and reconfigurable control is a new and actually developing field of science and engineering. The subject becomes more interesting since there is an increasing demand for the navigation and control systems of aerospace vehicles, automated actuators etc. to be more safe and reliable. Nowadays, the problems of fault detection and isolation and reconfigurable control attract the attention the scientists in the world. The subject is emphasized in the recent international congresses such as IF AC World Congresses (San Francisco-1996, Beijing-1999, and Barcelona-2002) and lMEKO World Congresses (Tampere-1997, Osaka-1999, Vienna-2000), and also in the international conferences on fault diagnosis such as SAFEPROCESS Conferences (Hull-1997, Budapest-2000). The presented methods in the book are based on linear and nonlinear dynamic mathematical models of the systems. Technical objects and systems stated by these models are very large, and include various control systems, actuators, sensors, computer systems, communication systems, and mechanical, hydraulic, pneumatic, electrical and electronic devices. The analytical fault diagnosis techniques of these objects have been developed for several decades. Many of those techniques are based on the use of the results of modem control theory. This is natural, because it is known that fault diagnosis process in control systems is considered as a part of general control process. xxii In organization of fault diagnosis of control systems, the use of the concepts and methods of modem control theory including concepts of state space, modeling, controllability, observability, estimation, identification, and filtering is very efficient.

A practical approach to operating survivable WDM networks

Abstract: Several methods have been developed for joint working and spare capacity planning in survivable wavelength-division-multiplexing (WDM) networks. These methods have considered a static traffic demand and optimized the network cost assuming various cost models and survivability paradigms. Our interest primarily lies in network operation under dynamic traffic. We formulate various operational phases in survivable WDM networks as a single integer linear programming (ILP) optimization problem. This common framework avoids service disruption to the existing connections. However, the complexity of the optimization problem makes the formulation applicable only for network provisioning and offline reconfiguration. The direct use of this method for online reconfiguration remains limited to small networks with few tens of wavelengths. Our goal in this paper is to develop an algorithm for fast online reconfiguration. We propose a heuristic algorithm based on LP relaxation technique to solve this problem. Since the ILP variables are relaxed, we provide a way to derive a feasible solution from the relaxed problem. The algorithm consists of two steps. In the first step, the network topology is processed based on the demand set to be provisioned. This preprocessing step is done to ensure that the LP yields a feasible solution. The preprocessing step in our algorithm is based on: (a) the assumption that in a network, two routes between any given node pair are sufficient to provide effective fault tolerance and (b) an observation on the working of the ILP for such networks. In the second step, using the processed topology as input, we formulate and solve the LP problem. Interestingly, the LP relaxation heuristic yielded a feasible solution to the ILP in all our experiments. We provide insights into why the LP formulation yields a feasible solution to the ILP We demonstrate the use of our algorithm on practical size backbone networks with hundreds of wavelengths per link. The results indicate that the run time of our heuristic algorithm is fast enough (in order of seconds) to be used for online reconfiguration.

Real-time LUT-based network topologies for dynamic and partial FPGA self-reconfiguration

Abstract: Xilinx Virtex FPGAs offer the possibility of dynamic and partial run-time reconfiguration. If a system uses this feature the designer has to take care, that no signal lines cross the border to other reconfigurable regions. Traditional solutions connecting modules on a dynamic and partial reconfigurable system use TBUF elements for connection and separation of the functional blocks. While automatically placing and routing the design, the routing-tool sometimes uses signal lines which cross the module border. The constraints given by the designer are ignored. To solve this problem, we use slices instead of TBUF elements which leads to a benefit by using an automatic modular design flow. This paper gives an overview of the used techniques and the complete system on a Xilinx XC2V3000 FPGA.

Skeleton-Network Reconfiguration Based on Topological Characteristics of Scale-Free Networks and Discrete Particle Swarm Optimization

Abstract: Black start, the restoration of a power system after a complete blackout, is a key issue to the safety of power systems. The reasonable network reconfiguration is necessary for establishing the main network and restoring loads quickly. Based on topological characteristics of scale-free networks and discrete particle swarm optimization, a skeleton-network reconfiguration strategy is proposed in this paper. Through calculating node importance degrees, priorities of sources and loads could be scaled quantitatively. Then, network reconfiguration efficiency, an index represented by network structure and subjected to restoration constrains, is used to evaluate the reconfiguration effect. Furthermore, discrete particle swarm optimization is employed in reconstructing skeleton networks that relieve reconfiguration burden considerably. Application examples verify that several optimal reconfiguration schemes achieved from the strategy can provide dispatchers an effective decision support under the uncertain system situation.