Robust fault-tolerant control

There are two main approaches to fault-tolerant control: passive and active.This thesis presents both methods for passive and for active FTC

An application of adaptive fault-tolerant control to nano-spacecraft

Since nano-spacecraft are small, low cost and do not undergo the same rigor of testing as conventional spacecraft, they have a greater risk of failure. In this paper we address the problem of attitude control of a nano-spacecraft that experiences different types of faults. Based on the traditional quaternion feedback control method, an adaptive fault-tolerant control method is developed, which can ensure that the control system still operates when the actuator fault happens. This paper derives the fault-tolerant control logic under both actuator gain fault mode and actuator deviation fault mode. Taking the parameters of the UKube-1 in the simulation model, a comparison between a traditional spacecraft control method and the adaptive fault-tolerant control method in the presence of a fault is undertaken. It is shown that the proposed controller copes with faults and is able to complete an effective attitude control manoeuver in the presence of a fault

Passive fault-tolerant control for vehicle active suspension system based on H2/H∞ approach

In this paper, a robust passive fault-tolerant control (RPFTC) strategy based on H2/H∞ approach and an integral sliding mode passive fault tolerant control (ISMPFTC) strategy based on H2/H∞ approach for vehicle active suspension are presented with considering model uncertainties, loss of actuator effectiveness and time-domain hard constraints of the suspension system. H∞ performance index less than γ and H2 performance index is minimized as the design objective, avoid choosing weighting coefficient. The half-car model is taken as an example, the robust passive fault-tolerant controller and the integral sliding mode passive fault tolerant control law is designed respectively. Three different fault modes are selected. And then compare and analyze the control effect of vertical acceleration of the vehicle body and pitch angular acceleration of passive suspension control, robust passive fault tolerant control and integral sliding mode passive fault tolerant control to verify the feasibility and effectiveness of passive fault tolerant control algorithm of active suspension. The studies we have performed indicated that the passive fault tolerant control strategy of the active suspension can improve the ride comfort of the suspension system

Fault diagnosis and fault-tolerant control for nonlinear systems with linear output structure

Article describes the process of fault diagnosis and fault-tolerant control for nonlinear systems with linear output structure

IMPLEMENTATION AND VALIDATION OF FAULT TOLERANT CONTROL OF A SELF-BEARING MOTOR CONSIDERING OPEN COIL FAULTS

Self-bearing motor is a magnetic actuator with both bearing and motoring functionality. This work implements and validates a decoupled and fault tolerant control algorithm for the Lorentz self bearing motor containing open phase faults. The goal of the algorithm is to achieve a stable bearing force and motoring torque even with coil faults. This work simulates many non-real-time fault tolerant control models based on the algorithm using simulink. Test cases are designed in simulink and tested on these models to arrive at the best model that could be implemented in dspace for real-time control. The responses of these simulations are compared with the desired output. Simulations showed that the decoupled and fault tolerant control model does not have any cross coupling and was fault tolerant for many combinations of open phase faults. Simulink model was modified so that it was auto-complied into the dspace controller and dynamically linked with the hardware. A graphical user interface was provided for fault tolerant control in controldesk software and the motor was controlled in real-time. Many experiments are designed to test the fault tolerant control model. Experimental results validate fault tolerance in the motor with respect to open coil faults. The self-bearing motor was found to be more stable in decoupled and fault tolerant control than non-fault tolerant control

Editorial for modelling, monitoring and fault-tolerant control for complex systems

This is the editorial for the special issue entitled ``Modelling, Monitoring and Fault-Tolerant Control for Complex Systems'' published in the Open Automation and Control Systems Journal

Integrated fault estimation and fault-tolerant control for stochastic systems with Brownian motions

This paper presents an integrated robust fault estimation and fault‐tolerant control technique for stochastic systems subjected to Brownian parameter perturbations. The augmented system approach, unknown input observer method, and optimization technique are integrated to achieve robust simultaneous estimates of the system states and the means of faults concerned. Meanwhile, a robust fault‐tolerant control strategy is developed by using actuator and sensor signal compensation techniques. Stochastic linear time‐invariant systems, stochastic systems with Lipschitz nonlinear constraint, and stochastic systems with quadratic inner‐bounded nonlinear constraint are respectively investigated, and the corresponding fault‐tolerant control algorithms are addressed. Finally, the effectiveness of the proposed fault‐tolerant control techniques is demonstrated via the drivetrain system of a 4.8 MW benchmark wind turbine, a 3‐tank system, and a numerical nonlinear model

Controllability Analysis and Degraded Control for a Class of Hexacopters Subject to Rotor Failures

This paper considers the controllability analysis and fault tolerant control problem for a class of hexacopters. It is shown that the considered hexacopter is uncontrollable when one rotor fails, even though the hexacopter is over-actuated and its controllability matrix is row full rank. According to this, a fault tolerant control strategy is proposed to control a degraded system, where the yaw states of the considered hexacopter are ignored. Theoretical analysis indicates that the degraded system is controllable if and only if the maximum lift of each rotor is greater than a certain value. The simulation and experiment results on a prototype hexacopter show the feasibility of our controllability analysis and degraded control strategy.Comment: 21 pages, 7 figures, submitted to Journal of Intelligent & Robotic System