U.S. patent application number 15/659107 was filed with the patent office on 2019-01-31 for controlling a cooling system for an internal combustion engine using feedback linearization.
The applicant listed for this patent is GM Global Technology Operations LLC. Invention is credited to Gabriele Giraudo.
Application Number | 20190032538 15/659107 |
Document ID | / |
Family ID | 65004277 |
Filed Date | 2019-01-31 |
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United States Patent
Application |
20190032538 |
Kind Code |
A1 |
Giraudo; Gabriele |
January 31, 2019 |
CONTROLLING A COOLING SYSTEM FOR AN INTERNAL COMBUSTION ENGINE
USING FEEDBACK LINEARIZATION
Abstract
Examples of techniques for controlling a cooling system for an
internal combustion engine using feedback linearization are
provided. In one example implementation, a computer-implemented
method includes receiving, by a processing device, desired
temperature targets. The method further includes receiving, by the
processing device, temperature feedbacks. The method further
includes calculating, by the processing device, a desired
temperature derivative for each of the desired temperature targets.
The method further includes calculating, by the processing device,
desired coolant flows from the desired temperature derivative for
each of the desired temperature targets using feedback
linearization. The method further includes calculating, by the
processing device, actuator commands from the desired coolant flows
using an inverted hydraulic model. The method further includes
implementing, by the processing device, the actuator commands in
actuators in the cooling system.
Inventors: |
Giraudo; Gabriele; (Torino,
IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GM Global Technology Operations LLC |
Detroit |
MI |
US |
|
|
Family ID: |
65004277 |
Appl. No.: |
15/659107 |
Filed: |
July 25, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01P 2060/12 20130101;
F01P 3/20 20130101; G01K 13/00 20130101; F01P 2050/16 20130101;
F01P 2060/045 20130101; F01P 2060/16 20130101; F01P 2023/00
20130101; F01P 7/16 20130101; F01P 2003/027 20130101; F01P 2007/146
20130101; F01P 7/165 20130101; F01P 2023/08 20130101; F01P 3/02
20130101; G05B 13/041 20130101 |
International
Class: |
F01P 7/16 20060101
F01P007/16; F01P 3/20 20060101 F01P003/20; G05B 13/04 20060101
G05B013/04; G01K 13/00 20060101 G01K013/00 |
Claims
1. A computer-implemented method for controlling a cooling system
for an internal combustion engine using feedback linearization, the
method comprising: receiving, by a processing device, desired
temperature targets; receiving, by the processing device,
temperature feedbacks; calculating, by the processing device, a
desired temperature derivative for each of the desired temperature
targets; calculating, by the processing device, desired coolant
flows from the desired temperature derivative for each of the
desired temperature targets using feedback linearization;
calculating, by the processing device, actuator commands from the
desired coolant flows using an inverted hydraulic model; and
implementing, by the processing device, the actuator commands in
actuators in the cooling system.
2. The computer-implemented method of claim 1, further comprising
measuring actual temperatures.
3. The computer-implemented method of claim 1, further comprising
determining actual temperatures using virtual sensors.
4. The computer-implemented method of claim 2, further comprising
inputting the actual temperatures into the feedback linearization
and the inverted hydraulic model.
5. The computer-implemented method of claim 4, wherein calculating
the desired coolant flows using the feedback linearization is based
at least in part on the actual temperatures.
6. The computer-implemented method of claim 4, wherein calculating
the actuator commands using the inverted hydraulic model is based
at least in part on the actual temperatures.
7. The computer-implemented method of claim 6, wherein calculating
the actuator commands using the inverted hydraulic model is based
at least in part on flow requests.
8. The computer-implemented method of claim 6, wherein calculating
the actuator commands using the inverted hydraulic model is based
at least in part on information that can force the actuator
commands to perform a specific task.
9. The computer-implemented method of claim 3, wherein calculating
the desired temperature derivative for each of the desired
temperature targets is based at least in part on the actual
temperatures.
10. The computer-implemented method of claim 1, wherein calculating
the desired temperature derivative for each of the desired
temperature targets is performed using a
proportional-integral-derivative controller.
11. The computer-implemented method of claim 1, further comprising
applying an anti-wind-up action.
12. A system for controlling a cooling system for an internal
combustion engine using feedback linearization, the system
comprising: a memory comprising computer readable instructions; and
a processing device for executing the computer readable
instructions for performing a method, the method comprising:
receiving, by the processing device, desired temperature targets;
receiving, by the processing device, temperature feedbacks;
calculating, by the processing device, a desired temperature
derivative for each of the desired temperature targets;
calculating, by the processing device, desired coolant flows from
the desired temperature derivative for each of the desired
temperature targets using feedback linearization; calculating, by
the processing device, actuator commands from the desired coolant
flows using an inverted hydraulic model; and implementing, by the
processing device, the actuator commands in actuators in the
cooling system.
13. The system of claim 12, the method further comprising measuring
actual temperatures.
14. The system of claim 12, the method further comprising
determining actual temperatures using virtual sensors.
15. The system of claim 13, the method further comprising inputting
the actual temperatures into the feedback linearization and the
inverted hydraulic model.
16. The system of claim 15, wherein calculating the desired coolant
flows using the feedback linearization is based at least in part on
the actual temperatures.
17. The system of claim 15, wherein calculating the actuator
commands using the inverted hydraulic model is based at least in
part on the actual temperatures.
18. The system of claim 17, wherein calculating the actuator
commands using the inverted hydraulic model is based at least in
part on flow requests.
19. The system of claim 17, wherein calculating the desired
temperature derivative for each of the desired temperature targets
is performed using a proportional-integral-derivative
controller.
20. A computer program product for controlling a cooling system for
an internal combustion engine using feedback linearization, the
computer program product comprising: a computer readable storage
medium having program instructions embodied therewith, wherein the
computer readable storage medium is not a transitory signal per se,
the program instructions executable by a processing device to cause
the processing device to perform a method comprising: receiving, by
the processing device, desired temperature targets; receiving, by
the processing device, temperature feedbacks; calculating, by the
processing device, a desired temperature derivative for each of the
desired temperature targets; calculating, by the processing device,
desired coolant flows from the desired temperature derivative for
each of the desired temperature targets using feedback
linearization; calculating, by the processing device, actuator
commands from the desired coolant flows using an inverted hydraulic
model; and implementing, by the processing device, the actuator
commands in actuators in the cooling system.
Description
INTRODUCTION
[0001] The present disclosure relates generally to internal
combustion engines and more particularly to controlling a cooling
system for an internal combustion engine using feedback
linearization.
[0002] A vehicle, such a car, a truck, a motorcycle, or any other
type of automobile may be equipped with an internal combustion
engine to provide a source of power for the vehicle. Power from the
engine can include mechanical power (to enable the vehicle to move)
and electrical power (to enable electronic systems, pumps, etc.
within the vehicle to operate). As an internal combustion engine
operates, the engine and its associated components generate heat,
which can damage the engine and its associated components if left
unmanaged.
[0003] To reduce heat in the engine, a cooling system circulates a
coolant fluid through cooling passages within the engine. The
coolant fluid absorbs heat from the engine and is then cooled via a
heat exchanger in a radiator when the coolant fluid is pumped out
of the engine and into the radiator. Accordingly, the coolant fluid
becomes cooler and is then circulated back through the engine to
cool the engine and its associated components.
SUMMARY
[0004] Examples of techniques for controlling a cooling system for
an internal combustion engine using feedback linearization are
provided. In one example embodiment, a computer-implemented method
includes receiving, by a processing device, desired temperature
targets. The method further includes receiving, by the processing
device, temperature feedbacks. The method further includes
calculating, by the processing device, a desired temperature
derivative for each of the desired temperature targets. The method
further includes calculating, by the processing device, desired
coolant flows from the desired temperature derivative for each of
the desired temperature targets using feedback linearization. The
method further includes calculating, by the processing device,
actuator commands from the desired coolant flows using an inverted
hydraulic model. The method further includes implementing, by the
processing device, the actuator commands in actuators in the
cooling system.
[0005] In another example embodiment, a system for controlling a
cooling system for an internal combustion engine using feedback
linearization is provided. The system includes a memory comprising
computer readable instructions and a processing device for
executing the computer readable instructions for performing a
method. The method includes receiving, by a processing device,
desired temperature targets. The method further includes receiving,
by the processing device, temperature feedbacks. The method further
includes calculating, by the processing device, a desired
temperature derivative for each of the desired temperature targets.
The method further includes calculating, by the processing device,
desired coolant flows from the desired temperature derivative for
each of the desired temperature targets using feedback
linearization. The method further includes calculating, by the
processing device, actuator commands from the desired coolant flows
using an inverted hydraulic model. The method further includes
implementing, by the processing device, the actuator commands in
actuators in the cooling system.
[0006] In another example embodiment, a computer program product
for controlling a cooling system for an internal combustion engine
using feedback linearization is provided. The computer program
product includes a computer readable storage medium having program
instructions embodied therewith, wherein the computer readable
storage medium is not a transitory signal per se, the program
instructions executable by a processing device to cause the
processing device to perform a method. The method includes
receiving, by a processing device, desired temperature targets. The
method further includes receiving, by the processing device,
temperature feedbacks. The method further includes calculating, by
the processing device, a desired temperature derivative for each of
the desired temperature targets. The method further includes
calculating, by the processing device, desired coolant flows from
the desired temperature derivative for each of the desired
temperature targets using feedback linearization. The method
further includes calculating, by the processing device, actuator
commands from the desired coolant flows using an inverted hydraulic
model. The method further includes implementing, by the processing
device, the actuator commands in actuators in the cooling
system.
[0007] According to one or more embodiments, the method further
includes measuring actual temperatures. According to one or more
embodiments, the method further includes determining actual
temperatures using virtual sensors. According to one or more
embodiments, the method further includes inputting the actual
temperatures into the feedback linearization and the inverted
hydraulic model. According to one or more embodiments, calculating
the desired coolant flows using the feedback linearization is based
at least in part on the actual temperatures. According to one or
more embodiments, calculating the actuator commands using the
inverted hydraulic model is based at least in part on the actual
temperatures. According to one or more embodiments, calculating the
actuator commands using the inverted hydraulic model is based at
least in part on flow requests. According to one or more
embodiments, calculating the actuator commands using the inverted
hydraulic model is based at least in part on information that can
force the actuator commands to perform a specific task. According
to one or more embodiments, calculating the desired temperature
derivative for each of the desired temperature targets is based at
least in part on the actual temperatures. According to one or more
embodiments, calculating the desired temperature derivative for
each of the desired temperature targets is performed using a
proportional-integral-derivative controller. According to one or
more embodiments, the method further includes applying an
anti-wind-up action.
[0008] The above features and advantages, and other features and
advantages of the disclosure, are readily apparent from the
following detailed description when taken in connection with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Other features, advantages, and details appear, by way of
example only, in the following detailed description, the detailed
description referring to the drawings in which:
[0010] FIG. 1 depicts an example of a thermal layout for a vehicle
engine, the vehicle engine including an actuator controller for
controlling a cooling system for the vehicle engine using feedback
linearization, according to embodiments of the present
disclosure;
[0011] FIG. 2 depicts a flow diagram of a method for controlling a
cooling system for the vehicle engine using feedback linearization,
according to embodiments of the present disclosure;
[0012] FIG. 3 depicts a flow diagram of a method for controlling a
cooling system for the vehicle engine using feedback linearization,
according to embodiments of the present disclosure; and
[0013] FIG. 4 depicts a block diagram of a processing system for
implementing the techniques described herein, according to
embodiments of the present disclosure.
DETAILED DESCRIPTION
[0014] The following description is merely exemplary in nature and
is not intended to limit the present disclosure, its application or
uses. It should be understood that throughout the drawings,
corresponding reference numerals indicate like or corresponding
parts and features. As used herein, the term module refers to
processing circuitry that may include an application specific
integrated circuit (ASIC), an electronic circuit, a processor
(shared, dedicated, or group) and memory that executes one or more
software or firmware programs, a combinational logic circuit,
and/or other suitable components that provide the described
functionality.
[0015] Existing cooling systems utilize a single input, single
output (SISO) approach. This means that each flow request is
calculated using only a single input, such as a temperature error.
However, as cooling systems increase in complexity, such as in
active thermal management, SISO control approaches may not be
appropriate. This means that existing SISO approaches are not
sufficient to manage the higher level of complexity and are not
sufficient to guarantee required performance. The reason is both
the higher number of actuators and the high level of interactions
within different zones within the cooling systems.
[0016] To address this problem, the technical solutions described
herein provide for controlling a cooling system for the vehicle
engine using feedback linearization. More particularly, the present
techniques provide for the use of a nonlinear multivariable
(multi-input, multi-output (MIMO)) control approach based on
physical dynamic models.
[0017] The present techniques can provide multiple benefits,
including a reduction of calibration effort, optimization of
actuator usage, systematic and robust control design,
simplification of control design for MIMO nonlinear systems, and
strong correlation between controls behavior and system physics.
Accordingly, these techniques can improve the efficiency of the
cooling system while reducing thermal stress on the engine, thereby
preventing possible damage to, or failure of, the engine and its
components. By controlling the flow of the coolant fluid, it is
possible to operate the engine at the highest temperature possible
without compromising the hardware integrity of the engine. This
increases engine and fuel efficiency while preventing failure of
the engine.
[0018] FIG. 1 depicts a thermal layout for a vehicle engine 100,
the vehicle engine includes an actuator controller 102 for
controlling a cooling system for the vehicle engine 100 using
feedback linearization, according to embodiments of the present
disclosure. According to one embodiment of the present disclosure,
the vehicle engine 100 includes at least an actuator controller
102, a primary coolant pump ("pump") 104, an engine block 110, an
engine head 112, other engine components 114 (e.g., a turbocharger,
an exhaust gas re-circulator, etc.), a main rotary valve (MRV) 130,
an engine oil heater 116, a transmission oil heater 118, a radiator
120, a flow control valve (FCV) 160, and a block rotary valve (BRV)
162. According to another embodiment of the present disclosure, the
vehicle engine includes the MRV 130 and an electrical pump. In yet
another embodiment of the present disclosure, the vehicle engine
100 includes the MRV 130 and the FCV 160. The transmission oil
heater 118 may only be needed in the case of an automatic
transmission and may not be included in the vehicle engine 100 in
some embodiments. The BRV 162 may only be needed in cases with
split cooling and may not be included in the vehicle engine 100 in
some embodiments.
[0019] According to one or more embodiments of the present
disclosure, the MRV 130 includes a first valve (or chamber) 140
having a first inlet 141, a second inlet 142, and an outlet 143.
The MRV 130 also includes a second valve (or chamber) 150 having an
inlet 151, a first outlet 152, and a second outlet 153. The various
components of the vehicle engine 100 are connected and arranged as
shown in FIG. 1 according to embodiments of the present disclosure,
and the solid lines among the components represent the fluid
connections among the components, with arrows representing the flow
direction of the fluid. According to other embodiments, the MRV 130
can be configured differently than shown.
[0020] According to examples of the present disclosure, the primary
pump 104 is a mechanical pump driven by the engine, such as through
a fan belt, a serpentine belt, or a timing belt. Secondary pump 106
is an electric pump that includes an electric motor driven by a
power source such as a battery (not shown) within the vehicle.
[0021] When the engine is running (on), coolant fluid is cooled by
the radiator 120 and is pumped out of the radiator 120 by the
primary pump 104 back into the engine block 110, the engine head
112, and the other components 114 (collectively, the "inlet" of the
engine). When the engine is not running (off), the primary pump 104
does not pump coolant fluid through the cooling system. However,
because the secondary pump 106 is an electric pump, it can pump
coolant fluid through the cooling system even when the engine is
not running. The actuator controller 102 can control the secondary
pump 106 to cause the secondary pump 106 to change flow rates of
the coolant fluid. The actuator controller 102 can also enable and
disable at least the secondary pump 106.
[0022] Coolant fluid cooled by the radiator 120 can also be pumped
directly into the first inlet 141 of the MRV 130. Managing the flow
out of the radiator 120 enables mixing cold coolant with hot
coolant in order to provide the coolant to the vehicle engine 100
at a desired temperature.
[0023] The actuator controller 102 controls the flow of coolant
fluid through the vehicle engine 100 by opening and closing the
first valve 140 and the second valve 150. Although not shown, each
valve within the vehicle engine 100 can have one or more actuators
associated therewith. The actuator controller 102 can send commands
to the one or more actuators to manipulate (e.g., open, close,
partially open, partially close) the valve associated therewith. In
particular, the actuator controller 102 can cause the second valve
150 to direct flow from the engine block 110 and the engine head
112 into the radiator 120 and/or the radiator bypass 122 through
the first outlet 152 and the second outlet 153. Similarly, the
actuator controller 102 can cause the first valve 140 to direct
flow from either the first inlet 141 and/or the second inlet 142
into the engine oil heater 116 and the transmission oil heater 118
through the outlet 143.
[0024] The first inlet 141 (also referred to as the "cold inlet")
receives cooled coolant fluid via the primary pump 104 from the
radiator 120. The second inlet 142 (also referred to as the "warm
inlet") receives warm coolant fluid (warm relative to the cooled
coolant fluid) after it is pumped by the primary pump 104 through
the engine block 110/engine head 112 and the other components 114.
The warm coolant fluid is warmed as it passes through the engine
block 110, the engine head 112, and/or the other components.
Accordingly, depending on the state of the first valve 140, the
first valve 140 can provide either cooled coolant fluid or warm
coolant fluid to the engine oil heater 116 and the engine
transmission oil heater 118.
[0025] To reduce an influx of cool coolant fluid in the engine
block 110 and the engine head 112, a flow control valve (FCV) 160
can be closed between the engine block 110/engine head 112 and the
second valve 150 of the MRV 130. In particular, an inlet of the FCV
160 is in fluid communication (directly and/or indirectly) with an
outlet of the engine block 110 and an outlet of the engine head
112, and an outlet of the FCV 160 is in fluid communication with
the inlet 151 of the second valve 150 of the MRV 130 and an inlet
of the other components 114.
[0026] When the FCV 160 is closed, the flow of coolant fluid into
the radiator 120 is stopped so the coolant fluid is not cooled by
the radiator 120. This prevents cooled coolant fluid from cycling
back into the engine block 110/engine head 112. The actuator
controller 102 controls the FCV 160 to open and shut the FCV 160
based at least in part on state changes of the MRV 130. According
to some embodiments, the FCV 160 is partially closed (e.g., closed
25%, closed 50%, closed 80%, etc.) to achieve a desired flow (e.g.,
to maintain a consistent temperature through the vehicle engine
100).
[0027] However, in some situations, the engine block 110 and the
engine head 112 may need different coolant fluid flow rates. For
example, the engine block 110 and the engine head 112 each require
a minimum flow to avoid boiling the coolant fluid and to prevent
high temperatures within each block, which may cause damage
thereto. Accordingly, the BRV 162 is introduced between an outlet
of the engine block 110 and an inlet of the FCV 160 so that the BRV
162 is in fluid communication with the engine block 110 and the FCV
160. The BRV 162 is controllable by the actuator controller 102 to
provide the ability to flow coolant fluid through each of the
engine block 110 and the engine head 112 at different rates.
[0028] The actuator controller 102 can continuously regulate the
FCV 160 and the BRV 162 to adjust the flow of coolant fluid that
the primary pump 104 and/or the secondary pump 106 can provide
through the engine block 110 and the engine head 112. By reducing
the flow of the primary pump 104 and/or the secondary pump 106, it
is possible to reduce also the load on the crankshaft (not shown),
to reduce engine friction, and to maximize combustion
efficiency.
[0029] With continuing reference to FIG. 1, in embodiments of the
present disclosure, the actuator controller 102 can be a
combination of hardware and programming. The programming may be
processor executable instructions stored on a tangible memory, and
the hardware can include a processing device for executing those
instructions. Thus a system memory can store program instructions
that when executed by the processing device implement the
functionality described herein. Other engines/modules/controllers
may also be utilized to include other features and functionality
described in other examples herein. Alternatively or additionally,
the actuator controller 102 can be implemented as dedicated
hardware, such as one or more integrated circuits, Application
Specific Integrated Circuits (ASICs), Application Specific Special
Processors (ASSPs), Field Programmable Gate Arrays (FPGAs), or any
combination of the foregoing examples of dedicated hardware, for
performing the techniques described herein.
[0030] FIG. 2 depicts a flow diagram of a method 200 for
controlling a cooling system for the vehicle engine using feedback
linearization, according to embodiments of the present disclosure.
The method 200 may be implemented, for example, by the actuator
controller 102 of FIG. 1, by the processing system 400 of FIG. 4,
or by another suitable processing system or device.
[0031] A block 202, the actuator controller 102 (i.e., a processing
device or processing system) receives desired temperature targets.
The temperature targets can be for coolant fluid in a cooling
system of the vehicle engine 100, for example; however, the
temperature targets can also be for metal, oil, or something
else.
[0032] At block 204, the actuator controller 102 receives
temperature feedbacks. The temperature feedbacks are measured
and/or estimated temperature values associated with the desired
temperature targets.
[0033] At block 206, the actuator controller 102 calculates a
desired temperature derivative for each of the desired temperature
targets. Calculating the desired temperature derivative for each of
the desired temperature targets is performed, for example, by a
proportional-integral-derivative (PID) controller, which may be
incorporated into the actuator controller 102, may be a separate
device, or may be incorporated into another device. A PID
controller is a control loop feedback mechanism that continuously
calculates an error value as a difference between the desired
temperature of the coolant fluid and a measured temperature of the
coolant fluid and applies a correction based on proportional,
integral, and/or derivative terms.
[0034] At block 208, the actuator controller 102 calculates desired
coolant flows from the desired temperature derivative for each of
the desired temperature targets using feedback linearization. Also
referred to as an inverted thermal model, feedback linearization
enables calculating desired coolant fluid flows based on desired
temperature derivatives. A thermal model can be expressed by the
following formula:
{dot over (T)}=A(T,T.sub.other)+B(T,T.sub.other){dot over (m)}
where {dot over (T)} is a vector of the derivatives of the
temperatures to be controlled in a closed loop, T is a vector of
the temperatures to be controlled in the closed loop, T.sub.other
is a vector containing all the temperatures that are not closed
loop controlled (e.g., environmental temperatures), A(T,
T.sub.other) is a vector in which a, is a non-linear function of
all temperatures within the cooling system (e.g., the natural
response of the cooling system), B(T, T.sub.other) is a square
matrix in which b.sub.ij is a non-linear function of all
temperatures within the cooling system (e.g., a forced response of
the cooling system), and {dot over (m)} is a vector containing zone
flows of coolant fluids to zones within the cooling system (e.g.,
the engine block 110, the engine head 112, the other components
114, etc.).
[0035] Feedback linearization is accomplished by inverting the
thermal model. The inverted thermal model for a desired temperature
of coolant fluid can be expressed as follows, using the variables
defined above:
{dot over (m)}.sub.DES=B(T,T.sub.other).sup.-1({dot over
(T)}.sub.DES-A(T,T.sub.other))
where {dot over (T)}.sub.DES is a vector of the derivative of the
desired temperature and {dot over (m)}.sub.DES is a vector
containing the desired coolant flow for a zone based on the desired
temperature.
[0036] At block 210, the actuator controller 102 calculates
actuator commands from the desired coolant flows using an inverted
hydraulic model. A hydraulic model is a mathematical model that
describes the cooling system and can be used to analyze the
behavior of the cooling system. By inverting the hydraulic model,
an actuator command can be calculated based on the desired coolant
flow. For example, an actuator command can be calculated as
follows:
ActCmd=f.sup.-1({dot over (m)}.sub.DES)
wherein f.sup.-1 represents the inverted hydraulic model and {dot
over (m)}.sub.DES is a vector containing the desired coolant flow
for a zone based on the desired temperature. This inversion takes
into account also other flow requests calculated in open loop, the
feedback temperature, the other temperatures (T.sub.other) and
other information that can force the actuator commands to do
something specific.
[0037] At block 212, the actuator controller 102 implements the
actuator commands in the cooling system. In other words, the
actuator command is input into an actuator associated with a valve
(e.g., the MRV 130, the FCV 160, the BRV 162, etc.) to manipulate
the valve to cause the valve to provide the desired flow of coolant
fluid. The actuator command can cause the valve to open or close an
appropriate amount so that the desired flow is provided.
[0038] Additional processes also may be included, and it should be
understood that the processes depicted in FIG. 2 represent
illustrations and that other processes may be added or existing
processes may be removed, modified, or rearranged without departing
from the scope and spirit of the present disclosure.
[0039] FIG. 3 depicts a flow diagram of a method 300 for
controlling a cooling system for the vehicle engine using feedback
linearization, according to embodiments of the present disclosure.
The method 300 may be implemented, for example, by the actuator
controller 102 of FIG. 1, by the processing system 400 of FIG. 4,
or by another suitable processing system or device.
[0040] A desired temperature (T.sub.DES) 302 is received at a block
304 along with a feedback temperature (T.sub.FB) 326. The block 304
calculates a vector of temperature errors (e.g., there is one error
for each controlled temperature) using the corresponding desired
temperatures 302 and feedback temperatures 326, and the temperature
error vector 306 input into a PID controller 308. The PID
controller 308 calculates a vector ({dot over (T)}.sub.DES) 310 of
the desired temperature derivatives. One of the differences between
this MIMO approach and existing SISO approaches is that flow
requests are calculated looking at all the PID outputs together,
where existing SISO approaches each flow request was the output of
one PID and no information from other flows/zones were
considered.
[0041] Based on the vector 310, the feedback temperatures 326 and
the other temperatures (T.sub.other), a feedback linearization
module 312 calculates the desired coolant flow vector ({dot over
(m)}.sub.DES) 314. The desired coolant flow vector 314 is converted
into actuator commands (ActCmd) 318 by the inverted hydraulic model
316. This inversion takes into account also other flow requests
calculated in open loop, the feedback temperature 326, the other
temperatures (T.sub.other) and other information that can force the
actuator commands to do something specific. The actuator commands
318 are input into actuators 320 to provide the desired flow 322 of
coolant fluid. The actuator commands can cause, for example, the
valve to open or close by an appropriate amount so that the desired
flow is provided. Actuators can be valves, electric pumps, and the
like.
[0042] Once the actuator provides the desired flow 322, the desired
flow of coolant fluid flows through the vehicle engine 100. A
sensor 324 can be used to measure the actual temperature of the
desired flow 322 to provide the feedback temperature 326, which is
used by the block 304, the feedback linearization module 312,
and/or the inverted hydraulic model 316 to adjust the calculations
described herein to more accurately achieve the desired temperature
302. According to some embodiments of the present disclosure, the
sensor 324 can be multiple sensors, a virtual sensor, or multiple
virtual sensors. In some situations, it is not possible to place a
sensor in a position in which it is desired to control the
temperature; therefore, is necessary to estimate that temperature
using a model and temperature information from other sensors using
a virtual sensor.
[0043] Additional processes also may be included, and it should be
understood that the processes depicted in FIG. 3 represent
illustrations and that other processes may be added or existing
processes may be removed, modified, or rearranged without departing
from the scope and spirit of the present disclosure.
[0044] The present techniques presented herein make several
assumptions. For example, the present techniques assume that the
hydraulic dynamic is faster than the temperature dynamic, which is
true. The present techniques also assume that the control model is
ideal. Although this is not necessarily true, the PID controller
308 can compensate for this. Finally, the present techniques assume
that all desired flows can be exactly realized. This is not true
because it may be necessary to guarantee minimum flows in certain
zones of the vehicle engine 100 and because a single valve for each
controlled zone may not be available. To solve this problem, an
anti-wind-up technique is implemented.
[0045] At an iteration k, it is possible to estimate {dot over (m)}
at step k-1 using a flow model in order to calculate the virtual
inputs vector V at prior iteration k-1, which can be used for the
anti-wind-up action using the following equations:
V.sub.k-1=A(T).sub.k-1+B(T).sub.k-1{dot over (m)}.sub.DES,k-1
INT.sub.k-1=V.sub.k-1-K.sub.P(T.sub.DES,k-1-T.sub.FB,k-1)
V.sub.k=K.sub.P(T.sub.DES,k-T.sub.FB,k)K.sub.I(T.sub.DES,k-T.sub.FB,k)+I-
NT.sub.k-1
where V.sub.k and V.sub.k-1 are vectors containing the virtual
inputs at iteration k and iteration k-1 respectively; A(T).sub.k-1,
B(T).sub.k-1, are the model matrices calculated at previous
iteration; {dot over (m)}.sub.k-1 are the previous iteration k-1
zone flows estimated using the flow model; T.sub.DES,k,
T.sub.DES,k-1 are vectors containing the desired temperatures at
iteration k and iteration k-1 respectively; T.sub.FB,k,
T.sub.FB,k-1 are vectors containing the feedback temperatures at
iteration k and iteration k-1 respectively; K.sub.P and K.sub.I are
the proportional and the integral gains (e.g., they should be two
scalar values for each closed loop); and INT.sub.k-1 is the
integral part at iteration k calculated as
V.sub.k-1-K.sub.P(T.sub.DES,k-1-T.sub.FB,k-1) to obtain the
anti-wind-up action. This anti-wind-up action enables the
compensation for guaranteeing minimum flows in certain zones and
for the fact that a single valve for each zone is not necessarily
available. Moreover, the anti-wind-up action compensates for the
fact that not all the flow requests can be realized
simultaneously.
[0046] The present MIMO techniques provide several benefits over
existing SISO solutions. For example, the present techniques
require minimal calibration effort, optimize actuator usage,
guarantee required performances, provide for managing complex
nonlinear systems, and strongly correlate controls behavior and
system physics.
[0047] It is understood that the present disclosure is capable of
being implemented in conjunction with any other type of computing
environment now known or later developed. For example, FIG. 4
illustrates a block diagram of a processing system 400 for
implementing the techniques described herein. In examples,
processing system 400 has one or more central processing units
(processors) 21a, 21b, 21c, etc. (collectively or generically
referred to as processor(s) 21 and/or as processing device(s)). In
aspects of the present disclosure, each processor 21 may include a
reduced instruction set computer (RISC) microprocessor. Processors
21 are coupled to system memory (e.g., random access memory (RAM)
24) and various other components via a system bus 33. Read only
memory (ROM) 22 is coupled to system bus 33 and may include a basic
inlet/outlet system (BIOS), which controls certain basic functions
of processing system 400.
[0048] Further illustrated are an inlet/outlet (I/O) adapter 27 and
a network adapter 26 coupled to system bus 33. I/O adapter 27 may
be a small computer system interface (SCSI) adapter that
communicates with a hard disk 23 and/or another storage drive 25 or
any other similar component. I/O adapter 27, hard disk 23, and
storage device 25 are collectively referred to herein as mass
storage 34. Operating system 40 for execution on processing system
400 may be stored in mass storage 34. A network adapter 26
interconnects system bus 33 with an outside network 36 enabling
processing system 400 to communicate with other such systems.
[0049] A display (e.g., a display monitor) 35 is connected to
system bus 33 by display adapter 32, which may include a graphics
adapter to improve the performance of graphics intensive
applications and a video controller. In one aspect of the present
disclosure, adapters 26, 27, and/or 32 may be connected to one or
more I/O busses that are connected to system bus 33 via an
intermediate bus bridge (not shown). Suitable I/O buses for
connecting peripheral devices such as hard disk controllers,
network adapters, and graphics adapters typically include common
protocols, such as the Peripheral Component Interconnect (PCI).
Additional inlet/outlet devices are shown as connected to system
bus 33 via user interface adapter 28 and display adapter 32. A
keyboard 29, mouse 30, and speaker 31 may be interconnected to
system bus 33 via user interface adapter 28, which may include, for
example, a Super I/O chip integrating multiple device adapters into
a single integrated circuit.
[0050] In some aspects of the present disclosure, processing system
400 includes a graphics processing unit 37. Graphics processing
unit 37 is a specialized electronic circuit designed to manipulate
and alter memory to accelerate the creation of images in a frame
buffer intended for outlet to a display. In general, graphics
processing unit 37 is very efficient at manipulating computer
graphics and image processing, and has a highly parallel structure
that makes it more effective than general-purpose CPUs for
algorithms where processing of large blocks of data is done in
parallel.
[0051] Thus, as configured herein, processing system 400 includes
processing capability in the form of processors 21, storage
capability including system memory (e.g., RAM 24), and mass storage
34, inlet means such as keyboard 29 and mouse 30, and outlet
capability including speaker 31 and display 35. In some aspects of
the present disclosure, a portion of system memory (e.g., RAM 24)
and mass storage 34 collectively store an operating system to
coordinate the functions of the various components shown in
processing system 400.
[0052] The descriptions of the various examples of the present
disclosure have been presented for purposes of illustration, but
are not intended to be exhaustive or limited to the embodiments
disclosed. Many modifications and variations will be apparent to
those of ordinary skill in the art without departing from the scope
and spirit of the described techniques. The terminology used herein
was chosen to best explain the principles of the present
techniques, the practical application or technical improvement over
technologies found in the marketplace, or to enable others of
ordinary skill in the art to understand the techniques disclosed
herein.
[0053] While the above disclosure has been described with reference
to exemplary embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from its scope.
In addition, many modifications may be made to adapt a particular
situation or material to the teachings of the disclosure without
departing from the essential scope thereof. Therefore, it is
intended that the present techniques not be limited to the
particular embodiments disclosed, but will include all embodiments
falling within the scope of the application.
* * * * *