A steering system for a vehicle includes a steerable wheel 1 capable of being steered, a steering wheel 20, and an electrical actuator 3 for altering the steering angle of the steerable wheel. The electrical actuator 3 has three electric motors 31, 32, 33 which act in parallel and three controllers 61, 62, 63 which operate in parallel, each forming part of an electrical control channel for the steering angle. The controller of each electrical channel receives one of the three electrical signals in the control channels and is connected to one of the position sensors and drives one of the electric motors in order to set the said steering angle. The torques delivered by the respective motors are added together in normal operation. The system also includes an interconnection bus 8 for the three electrical control channels, and means for detecting a discrepancy in the status of one electrical channel with respect to the other two, in order to give a malfunction warning and maintain operation in a downgraded mode in the event of a discrepancy. |