Open loop-style return for steer-by-wire (and closed-loop EPS) applications

1 . A method for augmenting a return velocity of a handwheel coupled to a steering system of a vehicle, the method comprising:

calculating a return-to-center (RtC) torque for the handwheel based on a vehicle speed and a position of the handwheel;

calculating a return load value for the handwheel based on the RtC torque;

adjusting an estimated rack load based on the return load value;

using an effort function, generating, based on the adjusted estimated rack value, an effort value, wherein the effort function defines a relationship between driver input and a response of the steering system, and wherein the effort value indicates an amount of effort required by the driver to cause a desired response; and

augmenting, based on the effort value and using the steering system, a return velocity of the handwheel.

2 . The method of claim 1 , wherein the steering system includes one of a steer-by-wire (SbW) system and a closed-loop electronic power steering (EPS) system.

3 . The method of claim 1 , further comprising calculating a handwheel torque scalar based on a torque applied to the handwheel and modifying the RtC torque based on the handwheel torque scalar.

4 . The method of claim 3 , further comprising calculating the handwheel torque scalar further based on the vehicle speed.

5 . The method of claim 1 , further comprising calculating the return load value by converting the RtC torque to the return load value based on an instantaneous C-factor.

6 . A system for augmenting a return velocity of a handwheel coupled to a steering system of a vehicle, the system comprising a processor configured to execute instructions stored in non-transitory computer readable memory, wherein, when executed, the instructions cause the processor to:

calculate return-to-center (RtC) torque for the handwheel based on a vehicle speed and a position of the handwheel;

calculate a return load value for the handwheel based on the RtC torque;

adjust an estimated rack load based on the return load value;

using an effort function, generate, based on the adjusted estimated rack value, an effort value, wherein the effort function defines a relationship between driver input and a response of the steering system, and wherein the effort value indicates an amount of effort required by the driver to cause a desired response; and

augment, based on the effort value and using the steering system, a return velocity of the handwheel.

7 . The system of claim 6 , wherein the steering system includes one of a steer-by-wire (SbW) system and a closed-loop electronic power steering (EPS) system.

8 . The system of claim 6 , wherein executing the instructions further causes the processor to calculate a handwheel torque scalar based on a torque applied to the handwheel and modify the RtC torque based on the handwheel torque scalar.

9 . The system of claim 8 , wherein executing the instructions further causes the processor to calculate the handwheel torque scalar further based on the vehicle speed.

10 . The system of claim 6 , wherein executing the instructions further causes the processor to calculate the return load value by converting the RtC torque to the return load value based on an instantaneous C-factor.

11 . A system for augmenting a return velocity of a handwheel coupled to a steering system of a vehicle, the system comprising:

one or more sensors configured to obtain a plurality of values corresponding to one or more steering functions of the vehicle; and

a controller configured to

calculate return-to-center (RtC) torque for the handwheel based on a vehicle speed and a position of the handwheel,

calculate a return load value for the handwheel based on the RtC torque,

adjust an estimated rack load based on the return load value,

using an effort function, generate, based on the adjusted estimated rack value, an effort value, wherein the effort function defines a relationship between driver input and a response of the steering system, and wherein the effort value indicates an amount of effort required by the driver to cause a desired response, and

augment, based on the effort value and using the steering system, a return velocity of the handwheel.

12 . The system of claim 11 , wherein the steering system includes one of a steer-by-wire (SbW) system and a closed-loop electronic power steering (EPS) system.

13 . The system of claim 11 , wherein the controller is further configured to calculate a handwheel torque scalar based on a torque applied to the handwheel and modify the RtC torque based on the handwheel torque scalar.

14 . The system of claim 13 , wherein the controller is further configured to calculate the handwheel torque scalar further based on the vehicle speed.

15 . The system of claim 11 , wherein the controller is further configured to calculate the return load value by converting the RtC torque to the return load value based on an instantaneous C-factor.