Method for controlling a steer-by-wire steering system with a reduced feedback in automatic drive mode

A method for controlling a steer-by-wire steering system for a motorized vehicle, the steer-by-wire steering system comprising a steering device control system for simulating a steering feel to a steering device, with the steering device control system including a first control unit;

• an actuation control system for actuating road wheels via a rack and pinion steering gear, with the actuation control system including a second control unit and an actuator;
• and an automatic driving electronic control unit for deciding based on input signals if a drive mode corresponds to vehicle-controlled steering or driver-controlled steering, the method comprising:
• detecting a status of the drive mode;
• and
• reporting the status to the first control unit via the automatic driving electronic control unit,
• wherein if the drive mode reported to the first control unit corresponds to driver-controlled steering, the method comprises rotating the steering device by a first steering device turning angle by activating the actuator according to a pre-set function depending on a rotation angle of a pinion of the rack and pinion steering gear to simulate the steering feel,
• wherein if the drive mode reported to the first control unit corresponds to vehicle-controlled steering, the method comprises rotating the steering device by a second steering device turning angle by activating the actuator according to the pre-set function multiplied by a factor of less than one.

A steer-by-wire steering system for a motorized vehicle comprising:

• a steering device control system for simulating a steering feel to a steering device, with the steering device control system including a first control unit;
• an actuation control system for actuating road wheels via a rack and pinion steering gear, with the actuation control system including a second control unit and an actuator;
• and
• an automatic driving electronic control unit for deciding based on input signals if a drive mode corresponds to vehicle-controlled steering or driver-controlled steering, wherein the automatic driving electronic control unit is configured to report a status of the drive mode to the first control unit,
• wherein under driver-controlled steering the first control unit is configured to activate the actuator according to a pre-set function depending on a rotation angle of a pinion of the rack and pinion steering gear to rotate the steering device by a first steering wheel turning angle to simulate the steering feel,
• wherein under vehicle-controlled steering the first control unit is configured to activate the actuator according to the pre-set function multiplied by a factor of less than one to rotate the steering device by a second steering wheel turning angle.