Fault-tolerant tracking control for a four-tank system benchmark via eigenstructure assignment and parameter estimation

While most research attention has been focused on fault detection and diagnosis, much less research effort has been devoted to failure accommodation. In this paper an active model based fault tolerant control system in case of major actuators failure is designed for a four-tank system benchmark and is simulated with the nonlinear model using Matlab. The four-tank system is regarded as a valuable experimental setup for investigating nonlinear multivariable feedback control as well as fault diagnosis. The faults are actuator faults that are modeled as a fall in actuators (pumps) gains which could lead to a large loss in the nominal performance. The fault tolerant controller is using an online parameter estimator as an FDD subsystem and an adaptive eigenstructure assignment state feedback controller as a reconfigurable controller. Simulation results are shown and compared with a non-fault-tolerant controller. The simulation results show promising performance increase due to the designed controller.