Use of on-vehicle accelerometer to estimate vehicle grade and mass while vehicle is in motion
View Patent ↗A system includes a grade estimation module that receives an accelerometer value and generates a grade estimate based on the accelerometer value, wherein the accelerometer value corresponds to acceleration of a vehicle and the grade estimate corresponds to a grade of the vehicle. A mass estimation module receives the accelerometer value and generates a mass estimate based on the accelerometer value, wherein the mass estimate corresponds to a mass of the vehicle. A shift control module at least one of selects and adjusts one of a plurality of shift schedules based on at least one of the grade estimate and the mass estimate and controls a transmission of the vehicle based on the one of the plurality of shift schedules.
1. A system comprising:
a grade estimation module that receives an accelerometer value and generates a grade estimate based on the accelerometer value, wherein the accelerometer value corresponds to acceleration of a vehicle and the grade estimate corresponds to a grade of the vehicle;
a mass estimation module that receives the accelerometer value and generates a mass estimate based on the accelerometer value, wherein the mass estimate corresponds to a mass of the vehicle; and
a shift control module that:
selects one of a plurality of shift schedules based on at least one of the grade estimate and the mass estimate;
adjusts the selected one of the plurality of shift schedules based on at least one of the grade estimate and the mass estimate; and
controls a transmission of the vehicle based on the one of the plurality of shift schedules.
2. The system of claim 1 further comprising an accelerometer that generates the accelerometer value.
3. The system of claim 1 wherein the grade estimation module generates the grade estimate based on the accelerometer value, a rate of change of vehicle speed, and a gravitational constant.
4. The system of claim 1 wherein the grade estimation module generates the grade estimate according to
Grade
%
=
(
arctan
(
sin
(
(
acceleration
-
rate
)
grav
)
)
)
*
100
,
wherein grade % corresponds to the grade estimate, acceleration corresponds to the accelerometer value, rate corresponds to a rate of change of vehicle speed, and gray corresponds to a gravitational constant.
5. The system of claim 1 wherein the mass estimation module generates the mass estimate based on the accelerometer value, tractive force of the vehicle, an aerodynamic coefficient of the vehicle, a speed of the vehicle, a rolling load of the vehicle, and braking force of the vehicle.
6. The system of claim 1 wherein the mass estimation module generates the mass estimate according to
Mass
=
(
tractive
-
(
aerocoeff
*
speed
2
)
-
rolling
-
braking
acceleration
)
,
where mass corresponds to the mass estimate, tractive corresponds to tractive force of the vehicle, aerocoeff corresponds to an aerodynamic coefficient of the vehicle, speed corresponds to a speed of the vehicle, rolling corresponds to a rolling load of the vehicle, braking corresponds to a braking force of the vehicle, and acceleration corresponds to the accelerometer value.
7. The system of claim 1 wherein the shift control module at least one of selects and adjusts the one of the plurality of shift schedules in response to the grade estimate being greater than or equal to a threshold.
8. The system of claim 1 wherein the shift control module at least one of selects and adjusts the one of the plurality of shift schedules in response to the mass estimate being greater than or equal to a threshold.
9. The system of claim 1 wherein the shift control module at least one of selects and adjusts the one of the plurality of shift schedules in response to the grade estimate being greater than or equal to a first threshold and the mass estimate being greater than or equal to a second threshold.
10. The system of claim 1 wherein the selected one of the plurality of shift schedules corresponds to one of a tow/haul shift schedule and a grade braking shift schedule.
11. A method comprising:
receiving an accelerometer value;
generating a grade estimate based on the accelerometer value, wherein the accelerometer value corresponds to acceleration of a vehicle and the grade estimate corresponds to a grade of the vehicle;
generating a mass estimate based on the accelerometer value, wherein the mass estimate corresponds to a mass of the vehicle;
selecting one of a plurality of shift schedules based on at least one of the grade estimate and the mass estimate;
adjusting the selected one of the plurality of shift schedules based on at least one of the grade estimate and the mass estimate; and
controlling a transmission of the vehicle based on the one of the plurality of shift schedules.
12. The method of claim 11 further comprising generating the accelerometer value using an accelerometer.
13. The method of claim 11 further comprising generating the grade estimate based on the accelerometer value, a rate of change of vehicle speed, and a gravitational constant.
14. The method of claim 11 further comprising generating the grade estimate according to
Grade
%
=
(
arctan
(
sin
(
(
acceleration
-
rate
)
grav
)
)
)
*
100
,
wherein grade % corresponds to the grade estimate, acceleration corresponds to the accelerometer value, rate corresponds to a rate of change of vehicle speed, and gray corresponds to a gravitational constant.
15. The method of claim 11 further comprising generating the mass estimate based on the accelerometer value, tractive force of the vehicle, an aerodynamic coefficient of the vehicle, a speed of the vehicle, a rolling load of the vehicle, and braking force of the vehicle.
16. The method of claim 11 further comprising generating the mass estimate according to
Mass
=
(
tractive
-
(
aerocoeff
*
speed
2
)
-
rolling
-
braking
acceleration
)
,
where mass corresponds to the mass estimate, tractive corresponds to tractive force of the vehicle, aerocoeff corresponds to an aerodynamic coefficient of the vehicle, speed corresponds to a speed of the vehicle, rolling corresponds to a rolling load of the vehicle, braking corresponds to a braking force of the vehicle, and acceleration corresponds to the accelerometer value.
17. The method of claim 11 further comprising at least one of selecting and adjusting the one of the plurality of shift schedules in response to the grade estimate being greater than or equal to a threshold.
18. The method of claim 11 further comprising at least one of selecting and adjusting the one of the plurality of shift schedules in response to the mass estimate being greater than or equal to a threshold.
19. The method of claim 11 further comprising at least one of selecting and adjusting the one of the plurality of shift schedules in response to the grade estimate being greater than or equal to a first threshold and the mass estimate being greater than or equal to a second threshold.
20. The method of claim 11 wherein the one of the plurality of shift schedules corresponds to one of a tow/haul shift schedule and a grade braking shift schedule.