Lateral asymmetry mitigation through side dependent understeer coefficient estimation
A system performs a method for operating a vehicle. The system includes a trajectory planning system for controlling a trajectory of the vehicle and a processor. The processor is configured to determine a left turn understeer coefficient for the vehicle using data obtained during a left turn of the vehicle, determine a right turn understeer coefficient for the vehicle using data obtained during a right turn of the vehicle, determine an arbitrated understeer coefficient from at least one of the left turn understeer coefficient and the right turn understeer coefficient, and provide the arbitrated understeer coefficient to the trajectory planning system. The trajectory planning system controls a lateral motion of the vehicle by operating the vehicle using the arbitrated understeer coefficient.
1 . A method of operating a vehicle, comprising:
determining a left turn understeer coefficient for the vehicle using data obtained during a left turn of the vehicle;
determining a right turn understeer coefficient for the vehicle using data obtained during a right turn of the vehicle;
determining an arbitrated understeer coefficient from at least one of the left turn understeer coefficient and the right turn understeer coefficient; and
control a lateral motion of the vehicle by operating the vehicle using the arbitrated understeer coefficient.
2 . The method of claim 1 , wherein at least one of: (i) a left caster angle is different than a right caster angle; and (ii) a left camber angle is different than a right camber angle.
3 . The method of claim 1 , further comprising determining the left turn understeer coefficient when a steering wheel angle is to a left side and is greater than a left turn enablement threshold and determining the right turn understeer coefficient when the steering wheel angle is to a right side and is greater than a right turn enablement threshold.
4 . The method of claim 1 , further comprising determining a wheel misalignment when a difference between the left turn understeer coefficient and the right turn understeer coefficient is greater than a difference threshold.
5 . The method of claim 1 , wherein selecting the arbitrated understeer coefficient further comprises at least one of: (i) selecting the left turn understeer coefficient; (ii) selecting the right turn understeer coefficient; (iii) selecting an average of the left turn understeer coefficient and the right turn understeer coefficient; and (iv) selecting a combination of the left turn understeer coefficient and the right turn understeer coefficient.
6 . The method of claim 5 , further comprising one of: (i) selecting the left turn understeer coefficient when the vehicle is making a left turn; and (ii) selecting the right turn understeer coefficient when the vehicle is making a right turn.
7 . The method of claim 1 , wherein controlling the lateral motion of the vehicle further comprises using a feedforward steering wheel angle calculated using the arbitrated understeer coefficient.
8 . A system for operating a vehicle, comprising:
a trajectory planning system for controlling a trajectory of the vehicle;
a processor configured to:
determine a left turn understeer coefficient for the vehicle using data obtained during a left turn of the vehicle;
determine a right turn understeer coefficient for the vehicle using data obtained during a right turn of the vehicle;
determine an arbitrated understeer coefficient from at least one of the left turn understeer coefficient and the right turn understeer coefficient; and
provide the arbitrated understeer coefficient to the trajectory planning system, wherein the trajectory planning system is configured to control a lateral motion of the vehicle by operating the vehicle using the arbitrated understeer coefficient.
9 . The system of claim 8 , wherein at least one of: (i) a left caster angle is different than a right caster angle; and (ii) a left camber angle is different than a right camber angle.
10 . The system of claim 8 , wherein the processor is further configured to determine the left turn understeer coefficient a steering wheel angle is to a left side and is greater than a left turn enablement threshold and determine the right turn understeer coefficient when the steering wheel angle is to a right side and is greater than a right turn enablement threshold.
11 . The system of claim 8 , wherein the processor is further configured to determine a wheel misalignment when a difference between the left turn understeer coefficient and the right turn understeer coefficient is greater than a difference threshold.
12 . The system of claim 8 , wherein the processor is further configured to select the arbitrated understeer coefficient by performing at least one of: (i) selecting the left turn understeer coefficient; (ii) selecting the right turn understeer coefficient; (iii) selecting an average of the left turn understeer coefficient and the right turn understeer coefficient; and (iv) selecting a combination of the left turn understeer coefficient and the right turn understeer coefficient.
13 . The system of claim 12 , wherein the processor is further configured to perform one of: (i) selecting the left turn understeer coefficient when the vehicle is making a left turn; and (ii) selecting the right turn understeer coefficient when the vehicle is making a right turn.
14 . The system of claim 8 , wherein the processor is further configured to control the lateral motion of the vehicle using a feedforward steering wheel angle calculated using the arbitrated understeer coefficient.
15 . A vehicle, comprising:
a sensor for measuring a steering wheel angle of the vehicle;
a trajectory planning system for controlling a trajectory the vehicle;
a processor configured to:
determine a left turn understeer coefficient for the vehicle using data obtained when the steering wheel angle indicates a left turn of the vehicle;
determine a right turn understeer coefficient for the vehicle using data obtained when the steering wheel angle indicates a right turn of the vehicle;
determine an arbitrated understeer coefficient from at least one of the left turn understeer coefficient and the right turn understeer coefficient; and
provide the arbitrated understeer coefficient to the trajectory planning system, wherein the trajectory planning system is configured to control a lateral motion of the vehicle by operating the vehicle using the arbitrated understeer coefficient.
16 . The vehicle of claim 15 , wherein at least one of: (i) a left caster angle is different than a right caster angle; and (ii) a left camber angle is different than a right camber angle.
17 . The vehicle of claim 15 , wherein the processor is further configured to determine the left turn understeer coefficient when the steering wheel angle is to a left side and is greater than a left turn enablement threshold and determine the right turn understeer coefficient when the steering wheel angle is to a right side and is greater than a right turn enablement threshold.
18 . The vehicle of claim 15 , wherein the processor is further configured to determine a wheel misalignment when a difference between the left turn understeer coefficient and the right turn understeer coefficient is greater than a difference threshold.
19 . The vehicle of claim 15 , wherein the processor is further configured to select the arbitrated understeer coefficient by performing at least one of: (i) selecting the left turn understeer coefficient; (ii) selecting the right turn understeer coefficient; (iii) selecting an average of the left turn understeer coefficient and the right turn understeer coefficient; and (iv) selecting a combination of the left turn understeer coefficient and the right turn understeer coefficient.
20 . The vehicle of claim 15 , wherein the processor is further configured to control the lateral motion of the vehicle using a feedforward steering wheel angle calculated using the arbitrated understeer coefficient.