Fault-tolerant Control Structure Research Articles

Performance-Based Sensor Reconfiguration for Fault-Tolerant Control of Uncertain Spatially Distributed Processes

This work focuses on the design of a fault detection and fault-tolerant control framework for spatially distributed processes modeled by highly-dissipative partial differential equations (PDEs) subject to external disturbances and sensor faults. The main objective is to devise a suitable sensor reconfiguration strategy to reduce the performance degradation due to the errors resulting from the sensor faults. Initially, a finite-dimensional system that captures the slow dynamics of the PDE is derived and used to design a obverse-based output feedback controller. Using Lyapunov techniques, the fault-free and faulty behavior of the closed-loop system are characterized in terms of the sensor spatial placement, the size of the disturbances, the magnitude of the sensor faults as well as the controller and observer design parameters. Based on the fault-free closed-loop dynamics, the Lyapunov stability bound is used as an alarm threshold to declare the presence of sensor faults. To suppress the performance deterioration, a performance-based sensor reconfiguration policy is developed whereby the supervisor determines either to continue using the current faulty sensors or to switch to suitable backup sensors based on a comparison between the sizes of the achievable terminal sets. A singular perturbation formulation is used to analyze the implementation of the sensor fault-tolerant control structure on the infinite-dimensional system. Finally, the results are illustrated through an application to a representative diffusion-reaction process example.

Research of Adaptive Fault-Tolerant Control Based on T-S Fuzzy Model

The adaptive fault-tolerant control problem for descriptor nonlinear system is researched in this paper. Contents include the properties of Adaptive Fault-tolerant like uncertainties, state delays, and input delays using T-S fuzzy model. First, the design of the state observer to estimate system state and sensor fault is introduced. Then, the adaptive fault-tolerant control structure with the state observer is proposed when combining with the sliding model control (SMC) and the adaptive generic model control (AGMC). Finally, an adaptive fault-tolerant control structure for nonlinear descriptor system is constructed. About above results, both of theoretical analysis and illustrative examples demonstrating the feasibility and validity were proposed.

Fault Tolerant Control of Aircraft Actuating Surfaces using Generalized DI and Integral SM Control

The paper introduces a new fault tolerant control structure against control surface failure, made by a combined use of Generalized Dynamic Inversion (GDI) control and Integral Sliding Mode control (ISMC). The null-control vector in the GDI-based control law parameterizes all the possible control functions that drive the aircraft trajectories to the sliding surface. A simple choice of the null-control vector is made, and is shown to yield closed-loop system stability for the nominal actuator scenario. The small gain theorem is employed to provide an explicit lower limit on the actuator efficiency matrix in the event of faults/failures. The efficacy of the proposed method in tolerating control surface actuator failure is demonstrated on the ADMIRE benchmark model.

An LPV pole-placement approach to friction compensation as an FTC problem

An LPV pole-placement approach to friction compensation as an FTC problemThe concept of combining robust fault estimation within a controller system to achieve active Fault Tolerant Control (FTC) has been the subject of considerable interest in the recent literature. The current study is motivated by the need to develop model-based FTC schemes for systems that have no unique equilibria and are therefore difficult to linearise. Linear Parameter Varying (LPV) strategies are well suited to model-based control and fault estimation for such systems. This contribution involves pole-placement within suitable LMI regions, guaranteeing both stability and performance of a multi-fault LPV estimator employed within an FTC structure. The proposed design strategy is illustrated using a nonlinear two-link manipulator system with friction forces acting simultaneously at each joint. The friction forces, regarded as a special case of actuator faults, are estimated and their effect is compensated within a polytope controller system, yielding a robust form of active FTC that is easy to apply to real robot systems.

A Control System Test Bed for Demonstration of Distributed Computational Intelligence Applied to Reconfi guring Heterogeneous Systems

Integrated ship system control is a challenging domain as it involves a set of highly complex and interdependent systems, including electrical power, electric drive propulsion, high-energy weapon systems, various auxiliary systems, and an underlying communications network. Many of the high-level system management questions demanding answers for the electric ship power system and ship service are directly related to control system architecture. As we move toward more decentralized, hierarchical systems, much work remains to be done to optimally determine the appropriate level of control and intelligence at each tier of the architecture. The body of knowledge in this area is limited with respect to power systems and is only slightly more developed for ship service systems. There is a significant need not only to address methods and algorithms from the standpoint of pure decentralization but also to address ways to migrate these methods into an actual distributed, fault-tolerant supervisory control structure that meets the requirements for implementation on the electric ship.