Linearized model based powertrain MPC

Patent metadata

Field	Value
Publication number	US-10358140-B2
Application number	US-201715719963-A
Country	US
Kind code	B2
Filing date	Sep 29, 2017
Priority date	Sep 29, 2017
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

A propulsion system, control system, and method are provided for optimizing fuel economy, which use model predictive control systems to generate a plurality of sets of possible command values and determine a cost for each set of possible command values based on weighting values, a plurality of predicted values, and a plurality of requested values. The set of possible command values having the lowest cost is determined. A linearized axle torque requested value and a linearized axle torque measured value are each created by subtracting an estimated disturbance. The estimated disturbance is determined based on a model of a relationship between measured engine output torque and measured transmission ratio. The linearized axle torque measured value is used to compute the predicted values, which are used to determine the cost. The linearized axle torque requested value is also used to determine the cost.

First claim

What is claimed is:

1. A method for controlling a propulsion system of a motor vehicle, the method comprising:
determining a plurality of requested values including a first requested value;
determining a plurality of measured values including a first measured value, a second measured value, and a third measured value;
determining an estimated disturbance based on a model of a relationship between the first and second measured values;
subtracting the estimated disturbance from the first requested value to establish a linearized requested value;
subtracting the estimated disturbance from the third measured value to establish a linearized measured value;
determining a plurality of predicted values based in part on the plurality of measured values including the linearized measured value;
generating a plurality of sets of possible command values;
determining a cost for each set of possible command values of the plurality of sets of possible command values based on a first predetermined weighting value, a second predetermined weighting value, the plurality of predicted values, and the plurality of requested values including the linearized requested value;
determining which set of possible command values of the plurality of sets of possible command values has a lowest cost;
selecting the set of possible command values that has the lowest cost to define a set of selected command values; and
controlling a vehicle parameter based on the selected command value.

2. The method of claim 1 , wherein the first measured value is an engine parameter, and the second measured value is a transmission parameter.

3. The method of claim 1 , wherein the first measured value is a measured engine output torque, the second measured value is a measured transmission ratio, the third measured value is a measured axle torque, and the first requested value is an axle torque requested.

4. The method of claim 3 , wherein the estimated disturbance is determined with the following equation:

D
=

{

(

Rat_m
k

*
100

-

Rat
off

)

⁢

(

Te_m
k

-
Te_off

)

⁢
FD

100

}

-

Loss
⁡

(

Rat_m
k

,

RPM_m
k

,

Te_m
k

)

where D is the estimated disturbance, FD is a final drive ratio, Rat_m k the measured transmission ratio at a prediction step k, Rat_off is a nominal offset set by ratio model linearization, Te_m k is the measured engine output torque at the prediction step k, Te_off is a nominal offset set by engine torque model linearization, loss is a mechanical loss factor, and RPM_m k is a measured engine speed at the prediction step k.

5. The method of claim 4 , further comprising controlling a vehicle parameter based on at least one selected command value of the set of selected command values.

6. The method of claim 5 , wherein the plurality of sets of possible command values includes a plurality of possible commanded engine output torque values and a plurality of possible commanded transmission ratio values and the set of selected command values includes a selected engine output torque value and a selected transmission ratio value, the method further comprising:
generating a plurality of predicted actual axle torque values and a plurality of predicted actual fuel consumption rate values based on the plurality of sets of possible command values; and
determining the cost for each set of possible command values further based on a predicted actual axle torque value of the plurality of predicted axle torque values and a predicted actual fuel consumption rate value of the plurality of predicted actual fuel consumption rate values.

7. The method of claim 6 , further comprising determining the plurality of predicted actual axle torque values and the plurality of predicted actual fuel consumption rate values with the following set of equations:

x

k
+
1

=

{

A
*

x
k

+

B
*

[

Te_c

Rat_c
k

]

+
v

}

+

K
KF

*

(

[

Te_m
k

FR_m
k

Assignees

• Gm Global Tech Operations Llc

Inventors

• Livshiz Michael
• Pattipati Bharath
• Bernardini Daniele
• Bemporad Alberto

Classifications

• B60W2510/0623

  Fuel flow rate · CPC title

• B60W30/188

  Controlling power parameters of the driveline, e.g. determining the required power · CPC title

• B60W10/06 Primary

  including control of combustion engines · CPC title

• B60W2540/10

  Accelerator pedal position · CPC title

• B60W2510/0638

  Engine speed · CPC title