MRAC-based Fault Tolerant Control of a SISO Real Process Application

In this paper, a modified version of Variable Structure Model Reference Adaptive Controller (VS-MRAC) scheme is developed for an application in Fault Tolerant Control (FTC) of a Single Input-Single Output (SISO) process. As a result of steady state error and oscillations when faults are induced in sensor and actuator of the process, the original VS-MRAC is modified by adding a Saturation Function and a PI controller (VS-MRAC-SAT-PI). The new scheme performance is compared against a classical PID and two other MRAC-based FTC schemes in a Coupled-Tank System. Different types of additive faults (abrupt and gradual faults) were induced in the process and results showed better fault accommodation capabilities of the VS-MRAC-SAT-PI.