Method for controlling a motor vehicle in the event of a fault in the front axle steering, and emergency steering system

A method for controlling a motor vehicle which has a steer-by-wire steering system having a front axle steering system and a rear axle steering system in the event of an identified fault of the front axle steering system, the method comprising:

• detecting vehicle signals relating to a steering specification, a position of a toothed rack of the front axle steering system and a yaw rate of the motor vehicle;
• providing the detected vehicle signals to a control unit;
• in order to convert the steering specification, generating, by the control unit, a first control signal for controlling a steering actuator of the rear axle steering system, wherein the first control signal is generated taking into consideration the steering specification, the position of the toothed rack of the front axle steering system and the yaw rate;
• and
• controlling the steering actuator of the rear axle steering system with the generated first control signal.

An emergency steering system for providing a capacity for steering a motor vehicle having a steer-by-wire steering system having a front axle steering system and a rear axle steering system, in the event of failure of the front axle steering system, comprising:

• a control unit, wherein a steering actuator of the rear axle steering system and actuators of the motor vehicle outside the steer-by-wire steering system are associated with the control unit;
• and
• a sensor unit for detecting a vehicle signal which relates to a steering specification and additional sensor units for detecting additional vehicle signals;
• wherein the control unit is configured to receive vehicle signals from the sensor units and to generate, from the received vehicle signals for converting the received steering specification, control signals for the steering actuator, which is associated with the control unit, of the rear axle steering system and the actuators of the motor vehicle outside the steer-by-wire steering system.