Abstract: In an embodiment of the present invention, an apparatus for steering a vehicle is disclosed. The apparatus includes a back-drivable steer-by-wire system including a road wheel actuator assembly coupled to a wheel of the vehicle. The road wheel actuator assembly defines a steering axis and the steering axis is off-set from a longitudinal axis of the wheel by a positive scrub radius. In an embodiment for a method in accordance with the present invention, a method to steer a vehicle after failure of a road wheel actuator assembly in a back-drivable steer-by-wire steering system is disclosed. The method includes the acts of applying a braking force to the wheel and generating a torque on the road wheel actuator assembly by the applied braking force acting through a positive scrub radius.

Abstract: A steering system for a vehicle includes a steering handle having a center position, a steer-by-wire system, and a steer feel control system. The steer-by-wire system senses the position of the steering handle and controls the steering angle of a steerable vehicle wheel as a function of the position of the steering handle. The steer feel control system includes a motor that is operatively associated with the steering handle, and has first and second modes of operation. In the first mode, the steer feel control system applies a force to the steering handle as a function of vehicle's operating condition, and in the second mode, the motor may be shorted. The steer feel control system may also include a spring that biases the steering handle towards to the center position. A method is used to provide steering feel to a steering handle of a vehicle having a steer-by-wire system and a steer feel control system, when the steer feel control system fails.

Abstract: In an embodiment of the present invention, an apparatus for steering a vehicle is disclosed. The apparatus includes a back-drivable steer-by-wire system including a road wheel actuator assembly coupled to a wheel of the vehicle. The road wheel actuator assembly defines a steering axis and the steering axis is off-set from a longitudinal axis of the wheel by a positive scrub radius. In an embodiment for a method in accordance with the present invention, a method to steer a vehicle after failure of a road wheel actuator assembly in a back-drivable steer-by-wire steering system is disclosed. The method includes the acts of applying a braking force to the wheel and generating a torque on the road wheel actuator assembly by the applied braking force acting through a positive scrub radius.

Abstract: A safety redundant drive by wire system includes a plurality of first control members to which control signals may be communicated and a plurality of device controllers adapted to deliver control signals to a respective first control member. Each device controller includes a first microprocessor for communicating control signals to the first control member and all other device controllers. Each device controller further includes a second microprocessor for redundantly communicating control signals to all other device controllers and for communicating with the first microprocessor. The system includes a dual redundant communication channel system having a first communication channel controlled by the first microprocessor of each device controller and a second communication channel controlled by the second microprocessor of each device controller.

Abstract: A safety redundant drive by wire system includes a plurality of first control members to which control signals may be communicated and a plurality of device controllers adapted to deliver control signals to a respective first control member. At least one sensor is coupled to each first control member for sensing a parameter of the first control member and responsively generating a sensor signal. Each device controller includes a first microprocessor for communicating control signals to the first control member and all other device controllers. Each device controller further includes a second microprocessor for redundantly communicating control signals to all other device controllers and for communicating with the first microprocessor. Each device controller is adapted to receive sensor signals and provide these sensor signals to the first and second microprocessors.