US 2019/0100217 A1Published application

Linearized model based powertrain mpc

AssigneeGM Global Technology Operations LLC

InventorsMichael Livshiz, Bharath Pattipati, Daniele Bernardini, Alberto Bemporad

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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.

Claims19

Dependent claims

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;
and
selecting the set of possible command values that has the lowest cost to define a set of selected command values.

8 more elements

A control system for a propulsion system of a motor vehicle having a transmission and an engine, the control system comprising:

a reference generator configured to generate a plurality of requested values including a first requested value;
a linearization module configured to generate an estimated disturbance based on a model of a relationship between first and second measured values, the control system being configured to subtract the estimated disturbance from the first requested value to establish a linearized requested value, and the control system being configured to subtract the disturbance from a third measured value to establish a linearized measured value;
a prediction module configured to generate a plurality of predicted values based in part on the first measured value, the second measured value, and the linearized measured value;
a command generator module configured to generate a plurality of sets of possible command values;
a cost module configured to:
determine 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;
and
determine which set of possible command values of the plurality of sets of possible command values has a lowest cost;
and
a selection module configured to select the set of possible command values that has the lowest cost to define a set of selected command values.

7 more elements

A propulsion system for a motor vehicle, comprising:

an engine operable to power the motor vehicle, the engine having an engine output shaft configured to transfer engine output torque;
a continuously variable transmission having a variator assembly including a first pulley and a second pulley, the first and second pulleys being rotatably coupled by a rotatable member, at least one of the first and second pulleys including a movable sheave translatable along an axis to selectively change a transmission ratio between the engine output shaft and a transmission output shaft;
a drive axle configured to be driven via the transmission output shaft, the drive axle being configured to output axle torque to a set of wheels;
and
a control system comprising:
a reference generator module configured to generate a plurality of requested values including an axle torque requested value;
a linearization module configured to generate an estimated disturbance based on a model of a relationship between a measured engine output torque value and a measure transmission ratio value, the control system being configured to subtract the estimated disturbance from the axle torque requested value to establish a linearized axle torque requested value, and the control system being configured to subtract the estimated disturbance from a measured axle torque value to establish a linearized axle torque measured value;
a command generator module configured to generate a plurality of sets of possible command values;
a prediction module configured to generate 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, the measured engine output torque value, the measured transmission ratio value, and the linearized axle torque measured value, the plurality of sets of possible command values including a plurality of possible commanded transmission ratio values and a plurality of possible commanded engine output torque values;
a cost module configured to:
determine 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 axle torque requested value;
and
determine which set of possible command values of the plurality of sets of possible command values has a lowest cost;
a selection module configured to select the set of possible command values that has the lowest cost to define a set of selected command values;
and
an actuation module configured to control a vehicle parameter based on at least one selected command value of the set of selected command values.

13 more elements

The propulsion system of claim 19, wherein the linearization module is configured to generate the estimated disturbance 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_mk the measured transmission ratio at a prediction step k, Rat_off is a nominal offset set by ratio model linearization, Te_mk 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_mk is a measured engine speed at the prediction step k, and wherein the prediction module is configured to determine 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
Rat_m
k
Ta_m
k
-
D
]
-
[
Te_a
k
FR_a
k
Rat_a
k
Ta_a
k
]
)


[
Ta_a
k
+
1
FR_a
k
+
1
]
=
C
*
x
k
+
1
+
w
where
xk+1=state variable at a prediction step k+1;
xk=state variable at a prediction step k;
A=a state matrix;
B=an input matrix;
Te_c=engine output torque commanded at the prediction step k;
Rat_ck=transmission ratio commanded at the prediction step k;
KKF=a Kalman filter gain;
Te_ak=predicted actual engine output torque at the prediction step k;
FR_ak=predicted actual fuel consumption rate at the prediction step k;
Rat_ak=predicted actual transmission ratio at the prediction step k;
Ta_ak=predicted actual axle torque at the prediction step k;
Te_mk=measured engine output torque at the prediction step k;
FR_mk=measured fuel consumption rate at the prediction step k;
Rat_mk=measured transmission ratio at the prediction step k;
Ta_mk=measured axle torque at the prediction step k;
D=estimated disturbance;
Ta_ak+1=predicted actual axle torque at the prediction step k+1;
FR_ak+1=predicted actual fuel consumption rate at the prediction step k+1;
C=an output matrix;
v=process noise;
and
w=measurement noise.

128 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/719,963Filed 29 Sep 2017
Published: 4 Apr 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification20 codes

B60W 50/0097
Details of control systems for road vehicle drive control not related to the control of a particular sub-unit , e.g. process diagnostic or…
B60W 10/06
Including control of propulsion units: including control of combustion engines
B60W 10/10
Conjoint control of vehicle sub-units of different type or different function: including control of change-speed gearings
B60W 10/107
Infinitely variable gearings: with endless flexible members