Fault tolerant control of electric power steering using robust filter-simulation study

This paper discusses a fault tolerant control (FTC) design in an electric power steering (EPS) system considering the case of a faulty torsion bar torque sensor. The total torque that acts on the assist motor shaft is the sum of the torsion bar torque and road torque. By estimating the road torque using the vehicle model and signals from the vehicle stability systems and the total torque on the assist motor shaft using a motor model based observer, the torsion bar torque sensor signal can be estimated. The parameter variation is also considered in order to give robust performance in practical case.