scholarly journals Restoration of target work in automatic failure- and fault-tolerant multitasking distributed information-control system

2019 ◽  
Author(s):  
A.V. Lobanov ◽  
I.V. Asharina
Keyword(s):  
Fault Tolerance ◽  
Digital Computer ◽  
Fault Tolerant ◽  
Recovery Process ◽  
Parallel Execution ◽  
Point Of View ◽  
Information Control ◽  
Distributed Information ◽  
Recovery Processes ◽  
Digital Computers

The paper deals with the organization of target work recovery processes after admissible failures and faults in an automatic failure and fault tolerant multitask distributed multi-machine system of the network structure performing a set of the target functions set by external users. The system is characterized by parallel execution of a set of interacting target tasks performed on separate computer subsystems, which are organized sets of digital computers. The specified level of failure- and fault-tolerance of the task is provided by its replication, i.e. parallel execution of copies of this task on several computers that make up the system, with the exchange of results and the choice of the correct one. The study introduces the characteristics, principles of construction, features of the considered systems and their "philosophical" essence from the point of view of failure- and fault-tolerance. Within the research, we determined the factors of complexity in the design of failure- and fault-tolerant systems of this class. The most general model of malicious computer failure is adopted, in which the computer behavior can be arbitrary, different in relation to other computers interacting with it, and even as malicious. We focus on the part of the problem of organizing dynamic redundancy in the developed system. The problem arises after an acceptable set of faults is detected in this system in some complex (or some set of F complexes) by each of the fault-free digital computers of each such complex and each such fault is also synchronously and consistently identified by place of origin and by type as a software failure of a certain digital computer of this complex. This part of the problem is solved by restoring all necessary information identified in a state of software malfunction of a certain complex. The information is transmitted to this digital computer from fault-free digital computers of this complex. The list of instructions required for such a recovery, as well as the actions of the complex in the recovery process, is determined.

scholarly journals Model-free reconfiguration mechanism for fault tolerance

2012 ◽  
Vol 22 (1) ◽  
pp. 125-137 ◽  
Author(s):  
Tushar Jain ◽  
Joseph Yamé ◽  
Dominique Sauter
Keyword(s):  
Fault Tolerance ◽  
Fault Diagnosis ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Vantage Point ◽  
Point Of View ◽  
Mathematical Framework ◽  
Tolerance Mechanism ◽  
Fault Accommodation ◽  
Model Free

Model-free reconfiguration mechanism for fault toleranceThe problem of fault tolerant control is studied from the behavioral point of view. In this mathematical framework, the concept of interconnection among the variables describing the system is a key point. The problem is that the behavior we intend to control is not known. Therefore, we are interested in designing a fault accommodation scheme for an unknown behavior through an appropriate behavioral interconnection. Here we deal simply with the trajectories that are generated by the system in real time. These trajectories determine the behavior of a system in various (faulty/healthy) modes. Based on the desired interconnected behavior, only the trajectories that obey certain laws are selected. These laws, representing the desired behavior, can indeed be achieved by a regular interconnection. Thus, when the trajectories do not belong to a certain desired behavior, it is considered to be due to the occurrence of a fault in the system. The vantage point is that the fault tolerant control problem now becomes completely a model-free scheme. Moreover, no explicit fault diagnosis module is required in our approach. The proposed fault tolerance mechanism is illustrated on an aircraft during the landing phase.

scholarly journals АНАЛІЗ МЕТОДІВ ПІДВИЩЕННЯ ВІДМОВОСТІЙКОСТІ СИСТЕМ КЕРУВАННЯ ЛІТАЛЬНИХ АПАРАТІВ

2020 ◽  
pp. 215-229
Author(s):  
А. М. Суббота ◽  
В. Г. Джулгаков
Keyword(s):  
Fault Tolerance ◽  
Angular Velocity ◽  
Fault Tolerant ◽  
Target Function ◽  
Failure Detection ◽  
The State ◽  
Point Of View ◽  
Space Technology ◽  
Diagnostic Systems ◽  
Angle Sensor

The issues related to the design of stabilization systems for aviation and rocket and space technology from the point of view of ensuring the main target function are considered: the system in operation must satisfy all the specified quality indicators, provided that it provides fault tolerance for a specified period of time. The general principles of designing fault-tolerant systems are analyzed in relation to the areas of Continuum, Fault Tolerant, Control by Diagnosis, which include modularity, independence of failures, redundancy, and quick failure detection. At the same time, the basic principles of improving fault tolerance are summarized and tabulated for clarity, among which are highlighted such as optimization, analytical redundancy, functional redundancy, reconfiguration, as well as the principles of quick failure detection based on self-monitoring and redundancy results. For systems with active fault-tolerance, examples are given of constructing diagnostic systems and making decisions about the serviceability of angular velocity sensors (AVS) used in aircraft stabilization channels. Specific schemes are presented and analyzed from the point of view of obtaining diagnosis results: schemes for constructing diagnostic systems based on two AVS by comparing their output signals, a hardware implementation diagram of a gyroscopic type AVS diagnostic unit with a potentiometric output transducer and a system for automatically switching a failed AVS to a similar backup one, and the scheme and principle of diagnostics with one working AVS in the autopilot scheme and one working outside the autopilot scheme. In order to reduce the overall mass characteristics during the design of aircraft stabilization systems with PD controllers, a reconfiguration scheme of the original system is proposed for failures of both the angle sensor (AS) and the angular velocity sensor. In addition, a directly algorithmic method was proposed for identifying faulty of AS and AVS in static-type autopilots, for which purpose components of the failure vector were introduced into the equations describing the dynamics of the aircraft stabilization system in the state space, by the state of which it is easy to determine the failed sensor.

Fault Tolerant Guidance of Under-Actuated Satellite Formation Flying Using Inter-Vehicle Coulomb Force

2019 ◽  
Vol 2 (1) ◽  
pp. 43-52
Author(s):  
Alireza Alikhani ◽  
Safa Dehghan M ◽  
Iman Shafieenejad
Keyword(s):  
Fault Tolerance ◽  
Formation Flying ◽  
Fault Tolerant ◽  
Coulomb Force ◽  
Control Law ◽  
Triangular Form ◽  
Satellite Formation Flying ◽  
Satellite Formation ◽  
Guidance Law ◽  
Tolerance Approach

In this study, satellite formation flying guidance in the presence of under actuation using inter-vehicle Coulomb force is investigated. The Coulomb forces are used to stabilize the formation flying mission. For this purpose, the charge of satellites is determined to create appropriate attraction and repulsion and also, to maintain the distance between satellites. Static Coulomb formation of satellites equations including three satellites in triangular form was developed. Furthermore, the charge value of the Coulomb propulsion system required for such formation was obtained. Considering Under actuation of one of the formation satellites, the fault-tolerance approach is proposed for achieving mission goals. Following this approach, in the first step fault-tolerant guidance law is designed. Accordingly, the obtained results show stationary formation. In the next step, tomaintain the formation shape and dimension, a fault-tolerant control law is designed.

Fault Tolerant Reliable Protocol (FTRP) Performance Evaluation in Wireless Sensor Networks: An Extensitive Study

2019 ◽  
pp. 1-36
Keyword(s):  
Wireless Sensor Networks ◽  
Fault Tolerance ◽  
Sensor Networks ◽  
Fault Tolerant ◽  
Cluster Head ◽  
Biological Data ◽  
Wireless Sensor ◽  
Delivery Ratio ◽  
Good Performer ◽  
Wide Range

Fault Tolerant Reliable Protocol (FTRP) is proposed as a novel routing protocol designed for Wireless Sensor Networks (WSNs). FTRP offers fault tolerance reliability for packet exchange and support for dynamic network changes. The key concept used is the use of node logical clustering. The protocol delegates the routing ownership to the cluster heads where fault tolerance functionality is implemented. FTRP utilizes cluster head nodes along with cluster head groups to store packets in transient. In addition, FTRP utilizes broadcast, which reduces the message overhead as compared to classical flooding mechanisms. FTRP manipulates Time to Live values for the various routing messages to control message broadcast. FTRP utilizes jitter in messages transmission to reduce the effect of synchronized node states, which in turn reduces collisions. FTRP performance has been extensively through simulations against Ad-hoc On-demand Distance Vector (AODV) and Optimized Link State (OLSR) routing protocols. Packet Delivery Ratio (PDR), Aggregate Throughput and End-to-End delay (E-2-E) had been used as performance metrics. In terms of PDR and aggregate throughput, it is found that FTRP is an excellent performer in all mobility scenarios whether the network is sparse or dense. In stationary scenarios, FTRP performed well in sparse network; however, in dense network FTRP’s performance had degraded yet in an acceptable range. This degradation is attributed to synchronized nodes states. Reliably delivering a message comes to a cost, as in terms of E-2-E. results show that FTRP is considered a good performer in all mobility scenarios where the network is sparse. In sparse stationary scenario, FTRP is considered good performer, however in dense stationary scenarios FTRP’s E-2-E is not acceptable. There are times when receiving a network message is more important than other costs such as energy or delay. That makes FTRP suitable for wide range of WSNs applications, such as military applications by monitoring soldiers’ biological data and supplies while in battlefield and battle damage assessment. FTRP can also be used in health applications in addition to wide range of geo-fencing, environmental monitoring, resource monitoring, production lines monitoring, agriculture and animals tracking. FTRP should be avoided in dense stationary deployments such as, but not limited to, scenarios where high application response is critical and life endangering such as biohazards detection or within intensive care units.

scholarly journals Fault Analysis and Non-Redundant Fault Tolerance in 3-Level Double Conversion UPS Systems Using Finite-Control-Set Model Predictive Control

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2210
Author(s):  
Luís Caseiro ◽  
André Mendes
Keyword(s):  
Fault Tolerance ◽  
Model Predictive Control ◽  
Predictive Control ◽  
Fault Tolerant ◽  
Finite Control ◽  
Control Set ◽  
Corrective Actions ◽  
Uninterruptible Power ◽  
Hardware Reconfiguration ◽  
Redundant Fault

Fault-tolerance is critical in power electronics, especially in Uninterruptible Power Supplies, given their role in protecting critical loads. Hence, it is crucial to develop fault-tolerant techniques to improve the resilience of these systems. This paper proposes a non-redundant fault-tolerant double conversion uninterruptible power supply based on 3-level converters. The proposed solution can correct open-circuit faults in all semiconductors (IGBTs and diodes) of all converters of the system (including the DC-DC converter), ensuring full-rated post-fault operation. This technique leverages the versatility of Finite-Control-Set Model Predictive Control to implement highly specific fault correction. This type of control enables a conditional exclusion of the switching states affected by each fault, allowing the converter to avoid these states when the fault compromises their output but still use them in all other conditions. Three main types of corrective actions are used: predictive controller adaptations, hardware reconfiguration, and DC bus voltage adjustment. However, highly differentiated corrective actions are taken depending on the fault type and location, maximizing post-fault performance in each case. Faults can be corrected simultaneously in all converters, as well as some combinations of multiple faults in the same converter. Experimental results are presented demonstrating the performance of the proposed solution.

scholarly journals An FTC Design via Multiple SOGIs with Suppression of Harmonic Disturbances for Five-Phase PMSG-Based Tidal Current Applications

2021 ◽  
Vol 9 (6) ◽  
pp. 574
Author(s):  
Zhuo Liu ◽  
Tianhao Tang ◽  
Azeddine Houari ◽  
Mohamed Machmoum ◽  
Mohamed Fouad Benkhoris
Keyword(s):  
Fault Tolerance ◽  
Energy Conversion ◽  
Tidal Current ◽  
Fault Tolerant ◽  
Tidal Current Energy ◽  
Electromagnetic Forces ◽  
Model Free ◽  
Energy Conversion Systems ◽  
Power Scale ◽  
Current Energy

This paper firstly adopts a fault accommodation structure, a five-phase permanent magnet synchronous generator (PMSG) with trapezoidal back-electromagnetic forces, in order to enhance the fault tolerance of tidal current energy conversion systems. Meanwhile, a fault-tolerant control (FTC) method is proposed using multiple second-order generalized integrators (multiple SOGIs) to further improve the systematic fault tolerance. Then, additional harmonic disturbances from phase current or back-electromagnetic forces in original and Park’s frames are characterized under a single-phase open condition. Relying on a classical field-oriented vector control scheme, fault-tolerant composite controllers are then reconfigured using multiple SOGIs by compensating q-axis control commands. Finally, a real power-scale simulation setup with a gearless back-to-back tidal current energy conversion chain and a small power-scale laboratory prototype in machine side are established to comprehensively validate feasibility and fault tolerance of the proposed method. Simulation results show that the proposed method is able to suppress the main harmonic disturbances and maintain a satisfactory fault tolerance when third harmonic flux varies. Experimental results reveal that the proposed model-free fault-tolerant design is simple to implement, which contributes to better fault-tolerant behaviors, higher power quality and lower copper losses. The main advantage of the multiple SOGIs lies in convenient online implementation and efficient multi-harmonic extractions, without considering system’s model parameters. The proposed FTC design provides a model-free fault-tolerant solution to the energy harvested process of actual tidal current energy conversion systems under different working conditions.

Optimization of Restoration Paths of Power System after Blackout

2013 ◽  
Vol 347-350 ◽  
pp. 1467-1472
Author(s):  
Wen Wei Huang ◽  
Gang Yao ◽  
Xiao Yan Qiu ◽  
Nian Liu ◽  
Guang Tang Chen
Keyword(s):  
Power System ◽  
Transmission Lines ◽  
Reactive Power ◽  
Minimum Spanning Tree ◽  
Operation Time ◽  
Combinatorial Problem ◽  
Weather Conditions ◽  
Recovery Process ◽  
Point Of View ◽  
Improved Genetic Algorithm

Optimization of restoration paths of power system after blackout is a multi-stage, multi-target, multi-variable combinatorial problem in the power system restoration. This paper presents a reasonable model and effectually method. The proposed model is considered as a typical partial minimum spanning tree problem from the mathematical point of view which considering all kinds of constraints. Improved data envelopment analysis (DEA) was used to get the weight which considering line charging reactive power, weather conditions, operation time and betweenness of transmission lines. The improved genetic algorithm method is employed to solve this problem. Finally, an example is given which proves the strategy of the line restoration can effectively handle the uncertainty of the system recovery process, to guarantee the system successfully restored after the catastrophic accidents.

A Design for Fault-Tolerant Communication Middleware Based on Time-Triggered

2014 ◽  
Vol 548-549 ◽  
pp. 1326-1329
Author(s):  
Juan Jin ◽  
Qing Fan Gu
Keyword(s):  
Fault Tolerance ◽  
Real Time ◽  
Fault Location ◽  
Fault Tolerant ◽  
Application Software ◽  
Tolerance Mechanisms ◽  
The Real ◽  
Communication Middleware ◽  
Fault Mechanism ◽  
Health Diagnosis

Against to the unsustainable problems of health diagnosis, fault location and fault tolerance mechanisms that existing in the current avionics applications, we proposed a fault-tolerant communication middleware which is based on time-triggered in this paper. This middleware is designed to provide a support platform for applications of the real-time based on communication middleware. From the communication middleware level and also combined with time-triggered mechanism and fault-tolerant strategy, it diagnoses the general faults first, and then routes them to the appropriate fault mechanism to process it. So the middleware completely separates fault-tolerant process from the application software functions.

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