Integration of fault detection and isolation with control in a multi–input multi–Output system

In this paper a algorithms is developed for fault diagnosis and fault tolerant control strategy for nonlinear systems subjected to an unknown timevarying fault vector is developed. At first, the design of fault diagnosis scheme is performed using model based fault detection technique. The fault magnitude and time of occurrence of fault is obtained through a transformation of residuals in to structured residuals. The estimated magnitude of the disturbance variable is used by the feed-forward control algorithm to make appropriate changes in the manipulated variable to keep the controlled variable near its set value. The feed-forward controller acts along with feedback controller to control the multivariable system. The performance of the proposed scheme is applied to a three-tank process for various types of disturbance inputs to show the effectiveness of the proposed approach