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 Fault monitoring and fault recovery control for position-moored vessels

2011 ◽  
Vol 21 (3) ◽  
pp. 467-478 ◽  
Author(s):  
Shaoji Fang ◽  
Mogens Blanke
Keyword(s):  
Fault Diagnosis ◽  
Position Control ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Mooring Line ◽  
Fault Recovery ◽  
Recovery Algorithm ◽  
Fault Accommodation ◽  
Fault Monitoring ◽  
Non Gaussian

Fault monitoring and fault recovery control for position-moored vessels This paper addresses fault-tolerant control for position mooring of a shuttle or floating production storage and offloading vessels. A complete framework for fault diagnosis is presented. A loss of a sub-sea mooring line buoyancy element and line breakage are given particular attention, since such failures might cause high-risk abortion of an oil-loading operation. With significant drift forces from waves, non-Gaussian elements dominate forces and the residuals designed for fault diagnosis. Hypothesis testing is designed using dedicated change detection for the type of distribution encountered. A new position recovery algorithm is proposed as a means of fault accommodation in order to keep the mooring system in a safe state, despite faults. The position control is shown to be capable of accommodating serious failures and preventing breakage of a mooring line, or a loss of a buoyancy element, from causing subsequent failures. Properties of the detection and fault-tolerant control algorithms are demonstrated by high fidelity simulations.

scholarly journals Active versus passive fault-tolerant control of a redundant multirotor UAV

2019 ◽  
Vol 124 (1273) ◽  
pp. 385-408
Author(s):  
M. Saied ◽  
B. Lussier ◽  
I. Fantoni ◽  
H. Shraim ◽  
C. Francis
Keyword(s):  
Fault Tolerance ◽  
Fault Detection ◽  
Active Fault ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Fault Tolerant Control ◽  
Fault Detection And Isolation ◽  
Detection Scheme ◽  
Redundancy Management ◽  
Model Free

ABSTRACTThis paper considers actuator redundancy management for a redundant multirotor Unmanned Aerial Vehicle (UAV) under actuators failures. Different approaches are proposed: using robust control (passive fault tolerance), and reconfigurable control (active fault tolerance). The robust controller is designed using high-order super-twisting sliding mode techniques, and handles the failures without requiring information from a Fault Detection scheme. The Active Fault-Tolerant Control (AFTC) is achieved through redistributing the control signals among the healthy actuators using reconfigurable multiplexing and pseudo-inverse control allocation. The Fault Detection and Isolation problem is also considered by proposing model-based and model-free modules. The proposed techniques are all implemented on a coaxial octorotor UAV. Different experiments with different scenarios were conducted for the validation of the proposed strategies. Finally, advantages, disadvantages, application considerations and limitations of each method are examined through quantitative and qualitative studies.

scholarly journals Fault-Tolerant Control for ROVs Using Control Reallocation and Power Isolation

2018 ◽  
Author(s):  
Romano Capocci ◽  
Edin Omerdic ◽  
Gerard Dooly ◽  
Daniel Toal
Keyword(s):  
Control System ◽  
Fault Detection ◽  
Virtual Instrument ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Fault Detection And Isolation ◽  
Control Allocation ◽  
Vertical Layer ◽  
Fault Accommodation ◽  
Model Free

This paper describes a novel thruster fault-tolerant control system (FTC) for open-frame remotely operated vehicles (ROVs). The proposed FTC consists of two subsystems: a model-free thruster fault detection and isolation subsystem (FDI) and a fault accommodation subsystem (FA). The FDI subsystem employs fault detection units (FDUs), associated with each thruster, to monitor their state. The robust, reliable and adaptive FDUs use a model-free pattern recognition neural network (PRNN) to detect internal and external faulty states of the thrusters in real time. The FA subsystem combines information provided by the FDI subsystem with predefined, user-configurable actions to accommodate partial and total faults and to perform an appropriate control reallocation. Software-level actions include penalisation of faulty thrusters in solution of control allocation problem and reallocation of control energy among the operable thrusters. Hardware-level actions include power isolation of faulty thrusters (total faults only) such that the entire ROV power system is not compromised. The proposed FTC system is implemented as a LabVIEW virtual instrument (VI) and evaluated in virtual (simulated) and real-world environments. The proposed FTC module can be used for open frame ROVs with up to 12 thrusters: eight horizontal thrusters configured in two horizontal layers of four thrusters each, and four vertical thrusters configured in one vertical layer. Results from both environments show that the ROV control system, enhanced with the FDI and FA subsystems, is capable of maintaining full 6 DOF control of ROV in the presence of up to 6 simultaneous total faults in the thrusters. With the FDI and FA subsystems in place the control energy distribution of the healthy thrusters is optimised so that the ROV can still operate in difficult conditions under fault scenarios.

RECONFIGURABLE CONTROL SYSTEM DESIGN FOR FAULT DIAGNOSIS AND ACCOMMODATION

2002 ◽  
Vol 12 (06) ◽  
pp. 497-520 ◽  
Author(s):  
LIANG-WEI HO ◽  
GARY G. YEN
Keyword(s):  
Fault Diagnosis ◽  
Control Problem ◽  
Real Time ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Effective Control ◽  
Dynamical Structure ◽  
The Real ◽  
Fault Accommodation ◽  
On Line

The growing demand in system reliability and survivability under failures has urged ever-increasing research effort on the development of fault diagnosis and accommodation. In this paper, the on-line fault tolerant control problem for dynamic systems under unanticipated failures is investigated from a realistic point of view without any specific assumption on the type of system dynamical structure or failure scenarios. The sufficient conditions for system on-line stability under catastrophic failures have been derived using the discrete-time Lyapunov stability theory. Based upon the existing control theory and the modern computational intelligence techniques, an on-line fault accommodation control strategy is proposed to deal with the desired trajectory-tracking problems for systems suffering from various unknown and unanticipated catastrophic component failures. Theoretical analysis indicates that the control problem of interest can be solved on-line without a complete realization of the unknown failure dynamics provided an on-line estimator satisfies certain conditions. Through the on-line estimator, effective control signals to accommodate the dynamic failures can be computed using only the partially available information of the faults. Several on-line simulation studies have been presented to demonstrate the effectiveness of the proposed strategy. To investigate the feasibility of using the developed technique for unanticipated fault accommodation in hardware under the real-time environment, an on-line fault tolerant control test bed has been constructed to validate the proposed technology. Both on-line simulations and the real-time experiment show encouraging results and promising futures of on-line real-time fault tolerant control based solely upon insufficient information of the system dynamics and the failure dynamics.

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.

scholarly journals Modeling and Fault Diagnosis of Interturn Short Circuit for Five-Phase Permanent Magnet Synchronous Motor

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Jian-wei Yang ◽  
Man-feng Dou ◽  
Zhi-yong Dai
Keyword(s):  
Parameter Estimation ◽  
Fault Diagnosis ◽  
Permanent Magnet ◽  
Fault Tolerant ◽  
Short Circuit ◽  
Estimation Method ◽  
Trust Region ◽  
Fault Tolerant Control ◽  
Trust Region Algorithm ◽  
Parameter Estimation Method

Taking advantage of the high reliability, multiphase permanent magnet synchronous motors (PMSMs), such as five-phase PMSM and six-phase PMSM, are widely used in fault-tolerant control applications. And one of the important fault-tolerant control problems is fault diagnosis. In most existing literatures, the fault diagnosis problem focuses on the three-phase PMSM. In this paper, compared to the most existing fault diagnosis approaches, a fault diagnosis method for Interturn short circuit (ITSC) fault of five-phase PMSM based on the trust region algorithm is presented. This paper has two contributions. (1) Analyzing the physical parameters of the motor, such as resistances and inductances, a novel mathematic model for ITSC fault of five-phase PMSM is established. (2) Introducing an object function related to the Interturn short circuit ratio, the fault parameters identification problem is reformulated as the extreme seeking problem. A trust region algorithm based parameter estimation method is proposed for tracking the actual Interturn short circuit ratio. The simulation and experimental results have validated the effectiveness of the proposed parameter estimation method.

Sign in / Sign up

Export Citation Format

Share Document