Design of a fault tolerant control system using Mahalanobis-Taguchi(MT) system

In this research, a failure tolerance control system design scheme using Mahalanobis-Taguchi (MT) system is proposed. In this method, we consider a situation that an actuator such as a heater gradually deteriorates and eventually breaks down. The failure detection component in a control system detects whether the system is broken, and switches to a backup actuator if a fault is detected in the actuator. In the proposed algorithm, an augmented system including an actuator is described as a first-order plus time-delay system, and their system parameters are estimated by the recursive least squares method. Unit space is designed using the estimated system parameters that are obtained during normal operation; based on the Mahalanobis distance, the failure detection component determines whether a newly obtained system parameter in operation belongs to the unit space. The control system switches to a backup actuator if the newly estimated parameters do not belong to the unit space. The effectiveness of this method is evaluated by simulation experiments.