Steer ratio synchronization for steer-by-wire systems

A method for a steer by wire steering system, the method comprising:

• determining a difference between a commanded steering ratio and an achieved steering ratio;
• determining whether the difference between the commanded steering ratio and the achieved steering ratio is greater than a threshold;
• in response to a determination that the difference between the commanded steering ratio and the achieved steering ratio is greater than the threshold, adjusting the commanded steering ratio to be equal to the achieved steering ratio;
• and
• in response to a determination that the difference between the commanded steering ratio and the achieved steering ratio is not greater than the threshold;
• selectively adjusting a bandwidth of a non-linear filter based one at least one vehicle characteristic of an associated vehicle;
• and
• adjusting, using the non-linear filter, the commanded steering ratio to be equal to a desired steering ratio, wherein the bandwidth is selectively adjusted to control a rate of change of the commanded steering ratio.

A system comprising:

• a processor;
• and
• a memory including instructions that, when executed by the processor, cause the processor to:
• determine a difference between a commanded steering ratio and an achieved steering ratio;
• determine whether the difference between the commanded steering ratio and the achieved steering ratio is greater than a threshold;
• in response to a determination that the difference between the commanded steering ratio and the achieved steering ratio is greater than the threshold, adjust the commanded steering ratio to be equal to the achieved steering ratio;
• and
• in response to a determination that the difference between the commanded steering ratio and the achieved steering ratio is not greater than the threshold:
• determine whether a handwheel position indicates that a handwheel of a vehicle is in a center position;
• in response to a determination that the handwheel position indicates that the handwheel of the vehicle is in the center position, selectively increase a bandwidth of a non-linear filter;
• in response to a determination that the handwheel position indicates that the handwheel of the vehicle is not in the center position, selectively decrease the bandwidth of the non-linear filter;
• and
• adjust, using the non-linear filter, the commanded steering ratio to be equal to a desired steering ratio, wherein the bandwidth is selectively adjusted to control a rate of change of the commanded steering ratio.