U.S. patent application number 16/764304 was filed with the patent office on 2021-05-13 for simulink modeling method for mechanical hydraulic device of aeroengine fuel regulator.
The applicant listed for this patent is DALIAN UNIVERSITY OF TECHNOLOGY. Invention is credited to Xian DU, Yanhua MA, Ximing SUN, Rui WANG, Xinyue WANG.
Application Number | 20210140382 16/764304 |
Document ID | / |
Family ID | 1000005550576 |
Filed Date | 2021-05-13 |
![](/patent/app/20210140382/US20210140382A1-20210513\US20210140382A1-2021051)
United States Patent
Application |
20210140382 |
Kind Code |
A1 |
SUN; Ximing ; et
al. |
May 13, 2021 |
SIMULINK MODELING METHOD FOR MECHANICAL HYDRAULIC DEVICE OF
AEROENGINE FUEL REGULATOR
Abstract
A Simulink modeling method for a mechanical hydraulic device of
an aeroengine fuel regulator is proposed. The Simulink modeling
method can implement high precision simulation of a mechanical
hydraulic device of an engine fuel conditioning system, and greatly
increase the simulation speed as compared with the existing
modeling simulation in AMESim; solve the problem of a
double-layered nested algebraic loop occurring when the mechanical
hydraulic device is modeled in Simulink, and improve the simulation
precision of the system. In addition, because of having certain
universality, the resolving method for a double-layered nested
algebraic loop can be generalized to resolve other types of
algebraic loops. Meanwhile, the parameters of the simulation model
provided by the present invention can be conveniently modified, and
can provide a reference for modeling simulation of mechanical and
hydraulic devices of engine fuel conditioning systems of other
types.
Inventors: |
SUN; Ximing; (Dalian,
Liaoning, CN) ; DU; Xian; (Dalian, Liaoning, CN)
; WANG; Rui; (Dalian, Liaoning, CN) ; MA;
Yanhua; (Dalian, Liaoning, CN) ; WANG; Xinyue;
(Dalian, Liaoning, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DALIAN UNIVERSITY OF TECHNOLOGY |
Dalian, Liaoning |
|
CN |
|
|
Family ID: |
1000005550576 |
Appl. No.: |
16/764304 |
Filed: |
March 15, 2019 |
PCT Filed: |
March 15, 2019 |
PCT NO: |
PCT/CN2019/078244 |
371 Date: |
May 14, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02D 41/28 20130101;
F02D 41/222 20130101; F02D 2041/202 20130101; F02D 2041/223
20130101; F02D 2041/286 20130101; F02D 41/20 20130101; F02D 41/18
20130101 |
International
Class: |
F02D 41/20 20060101
F02D041/20; F02D 41/22 20060101 F02D041/22; F02D 41/28 20060101
F02D041/28; F02D 41/18 20060101 F02D041/18 |
Claims
1. A Simulink modeling method for a mechanical hydraulic device of
an aeroengine fuel regulator, comprising the following steps: S1.
modeling a main differential pressure control loop of a mechanical
hydraulic device of an engine fuel conditioning system using an
analytical method, the main differential pressure control loop
including a metering valve, an oil return valve and a differential
pressure valve; modeling the main differential pressure control
loop of the mechanical hydraulic device comprises the following
steps: S1.1. first, determining input and output parameters of the
metering valve, the input parameters including metering valve flow
Qjiliang, metering valve expected displacement ExDisp, fuel density
Density and after metering valve fuel pressure Pout_JL, and the
output parameters including metering valve displacement Disp, fore
metering valve fuel pressure Pin_JL and metering valve flow
FUEL_Supply; S1.2. since the metering valve internally includes a
displacement calculation module and a pressure calculation module,
inputting the metering valve expected displacement ExDisp into the
displacement calculation module, obtaining a current input signal
of an electrohydraulic servo valve through PID control, obtaining
an output flow according to input and output characteristics of the
electrohydraulic servo valve, obtaining a moving speed of the
metering valve by dividing the output flow by area, and obtaining
displacement of the valve through the integral link; and for the
pressure calculation module, according to the mass flow formula: Q
= .mu. .times. .times. A .times. .DELTA. .times. .times. P * 2
.times. .rho. ##EQU00020## obtaining ##EQU00020.2## Pin_JL = Q 2
.mu. 2 .times. A 2 * 1 2 .times. .rho. + Pout_JL ##EQU00020.3##
where Q represents fuel mass flow of the metering valve, u
represents flow coefficient, A represents flow area of the metering
valve, .DELTA.P represents difference between fore and after
metering valve pressures, and p represents fuel density; S1.3.
determining input and output parameters of the oil return valve,
the input parameters including after gear pump fuel pressure
P.sub.1, output fuel pressure P.sub.2 of the differential pressure
valve, after stopping valve fuel pressure P.sub.2P, fuel supply
quantity Q_chilunbeng of the gear pump and fuel density Density,
and the output parameters including fuel return quantity Q_huiyou
of the oil return valve, oil return valve displacement X, and
metering valve flow Q_jiliang; S1.4. since the oil return valve
internally includes a displacement calculation module and a flow
calculation module, calculating the displacement according to the
following calculation formula: X=X.sub.1+X.sub.2 where X represents
displacement of the oil return valve, X.sub.1 represents
displacement of a left spring of the oil return valve, and X.sub.2
represents displacement of an intermediate spring of the oil return
valve, for the left spring,
P.sub.1*A.sub.1+P.sub.2P*A.sub.2-P.sub.2P*A.sub.3-P.sub.2*A.sub.4=K.sub.2-
*(X.sub.2+X.sub.20) and for the intermediate spring,
P.sub.1*A.sub.5-P.sub.2P*A.sub.5=K.sub.1*(X.sub.1+X.sub.10) where
P.sub.1 represents fore metering valve fuel pressure, that is,
after gear pump fuel pressure; A.sub.1 represents area of action of
fuel of the gear pump, and P.sub.2P represents after stopping valve
fuel pressure; A.sub.2 represents left area of action of a left
spring chamber, A.sub.3 represents right area of action of the
intermediate spring, P.sub.2 represents output fuel pressure of the
differential pressure valve, A.sub.4 represents area of action of
the left spring chamber, A.sub.5 represents equivalent area of
action of the intermediate spring, K.sub.1 represents stiffness
coefficient of the intermediate spring, X.sub.10 represents initial
compression amount of the intermediate spring, K.sub.2 represents
stiffness coefficient of the left spring, and X.sub.20 represents
initial compression amount of the left spring; S1.5. calculating
the flow area of the oil return valve through the total
displacement of the oil return valve output by the displacement
calculation module, then substituting same into the mass flow
formula to obtain the fuel return quantity of the oil return valve,
and subtracting the fuel return quantity from the after total flow
of the gear pump to obtain the fuel flow of the metering valve;
S1.6. determining input and output parameters of the differential
pressure valve, the input parameters including after gear pump fuel
pressure P.sub.1 and spring chamber fuel pressure P_tanhuangqiang
of the differential pressure valve, and the output parameter
including fuel pressure P.sub.2 of control fuel of the differential
pressure valve; S1.7. performing calculation on the differential
pressure valve mainly using the spring compression module and the
pressure calculation module, wherein the mathematical model of the
spring compression module is:
P.sub.1*S.sub.1+P.sub.tan*(S.sub.4-S.sub.2-S.sub.3)+P.sub.2*S.sub.5+*(X-0-
.0001)*(X.gtoreq.0.0001)+f.sub.10-f.sub.20=(K.sub.1+K.sub.2)*X
where P.sub.tan represents spring chamber fuel pressure of the
differential pressure valve, f.sub.10 represents pretightening
force of bellows of the differential pressure valve, f.sub.20
represents pretightening force of spring of the differential
pressure valve, S.sub.1 represents area of action of fluid of the
bellows, S.sub.2 represents area of action of fluid of the spring
chamber, S.sub.3 represents area of action of low pressure fuel at
the upper end of a nozzle baffle, S.sub.4 represents area of action
of low pressure fuel at the lower end of the nozzle baffle, S.sub.5
represents area of action of the control fuel, K.sub.2 represents
stiffness coefficient of the spring, K.sub.1 represents stiffness
coefficient of the bellows, and the main modeling basis of the
pressure calculation module is the following partial pressure
formula: P 2 = S 6 2 * P 1 + S 7 2 * P tan S 6 2 + S 7 2
##EQU00021## where S.sub.6 represents area of action of fore fluid
of the metering valve, and S.sub.7 represents area of action of
fluid of the spring chamber; S1.8. adding a displacement-area
interpolation table in the metering valve and differential pressure
valve module, and according to the structure principle of the
metering valve, the oil return valve and the differential pressure
valve, connecting inputs and outputs of the three valves, to form a
main differential pressure control loop; modeling the main fuel
circuit of the mechanical hydraulic device comprises the following
steps: S1.9. according to the flow direction of the main fuel
circuit, determining the constitution modules of the main fuel
circuit, including a gear pump, an oil return valve, a metering
valve, a high pressure shut-off valve, a throttle nozzle and a
combustion chamber; S1.10. according to the flow equation of the
main fuel circuit, determining the flow differential pressure
equation of each module by the backward induction idea of the
differential pressure, and implementing same in Simulink; S1.11. in
addition to the mass flow equation, the mathematical model of the
high pressure shut-off valve also includes a displacement
calculation module, the pressure of action of fluid of the upper
chamber thereof is: F I = P B * ( D P 2 - D R 2 ) * .pi. 4
##EQU00022## where P.sub.B represents fuel pressure at inlet of the
high pressure shut-off valve, D.sub.P represents diameter of upper
chamber of the valve, D.sub.R represents rod diameter of upper
chamber of the valve, and in the equilibrium state, the fluid
pressure and spring force satisfy the following equation:
F.sub.1=P.sub.sp*A.sub.L+K.sub.s*X+F.sub.0 where A.sub.L represents
area of action of fluid of the spring chamber, P.sub.sp represents
fuel pressure of the spring chamber, F.sub.0 represents
pretightening force of the spring, K.sub.s represents stiffness
coefficient of the spring, X represents displacement of the spring,
that is, displacement of the high pressure shut-off valve,
obtaining the flow area of the high pressure shut-off valve through
the displacement-area interpolation table, and feeding same back to
the mass flow equation of the pressure calculation module; modeling
other components of the mechanical hydraulic device comprises the
following steps: S1.12. selecting a Switch module to switch the
operating state of the stopping valve: if the input signal of the
stopping valve is 0, outputting low pressure fuel to the spring
chamber of the high pressure shut-off valve, so the high pressure
shut-off valve opens and the engine operates normally; and if the
input signal of the stopping valve is greater than 0, outputting
high pressure fuel to the spring chamber of the high pressure
shut-off valve, so the high pressure shut-off valve closes and the
fuel conditioning system stops; S1.13. selecting the Switch module
to switch the operating state of an overturn protection device: if
the overshoot signal is 0, that is, the engine normally operates,
and the overturn protection device does not operate, directly
inputting the after control fuel of a switch valve to the spring
chamber of the differential pressure valve; and if the engine
overturns and the overshoot signal is not 0, introducing, by the
overturn protection device, the low pressure fuel into the spring
chamber of the differential pressure valve, so the flow of the
metering valve is reduced, and the overturn protection function is
achieved; S1.14. selecting the Switch module to switch the
operating state of the switch valve: in the case of non-stopping
state, both the upper chamber and lower chamber of the switch valve
are in communication with the fuel tank, thereby outputting low
pressure fuel to the spring chamber of the differential pressure
valve; and in the case of stopping state, the lower chamber of the
switch valve is in communication with the high pressure fuel, and
at this moment, according to the partial pressure formula, by the
same as the partial pressure principle as the differential pressure
valve, the output fuel pressure of the switch valve is obtained;
S2. modeling the main fuel circuit for fuel of the mechanical
hydraulic device, that is, the fuel circuit from the gear pump to
the fuel dispenser through the metering valve, the high pressure
shut-off valve and the throttle nozzle, according to the pressure
backward induction idea; S3. after modeling the main differential
pressure control loop and the main fuel circuit, continuing to
build models for other components of the mechanical hydraulic
device in Simulink, including the stopping valve and the switch
valve; S4. for the double-layered nested algebraic loops occurring
in model simulation, resolving the algebraic loops using the method
of inserting high frequency delay, and thus improving the model
simulation speed and precision; resolving the double-layered nested
algebraic loops in the model comprises the following steps: S4.1.
inserting high-frequency delay in the form of G .function. ( s ) 1
+ G .function. ( s ) ##EQU00023## in the inner layer feedback loop
of the high pressure shut-off valve, where G .function. ( s ) = k 1
* 1 s , ##EQU00024## and setting a parameter k.sub.1 to make the
high pressure shut-off valve output a correct result; S4.2.
inserting high-frequency delay in the form of G .function. ( s ) 1
+ G .function. ( s ) ##EQU00025## in the inner layer feedback loop
of the differential pressure valve, where G .function. ( s ) = k 2
* 1 s , ##EQU00026## and setting a parameter k.sub.2 to make the
differential pressure valve output a correct result; S4.3.
inserting high-frequency delay in the form of G .function. ( s ) 1
+ G .function. ( s ) ##EQU00027## in the outer layer control loop
of the metering valve, where G .function. ( s ) = k 3 * 1 s ,
##EQU00028## and setting a parameter k.sub.3 to make the control
loop of the metering valve output a correct result; S4.4. adjusting
the parameters k.sub.1, k.sub.2, k.sub.3, so that the inner layer
frequency of the algebraic loop is higher than the outer layer
frequency, to achieve resolving of the double-layered nested
algebraic loops, and adjusting the parameters to the state where
the system operates stably and outputs a correct result; S5.
according to the field test data, correcting the PID module in the
model and system input and output to achieve high precision
simulation of the mechanical hydraulic device of the aeroengine
fuel conditioning system.
Description
TECHNICAL FIELD
[0001] The present invention proposes a modeling method for a
mechanical hydraulic device of an aeroengine fuel regulator based
on Simulink, which belongs to the technical field of modeling for
mechanical hydraulic devices of aeroengines.
BACKGROUND
[0002] The background on which the present invention relies on is
MATLAB/Simulink modeling for a mechanical hydraulic device of a
certain type of aeroengine fuel conditioning system.
[0003] A fuel conditioning system is a core component for automatic
control of an engine, and is also a high-risk area. Under the
digital demand of the aeroengine fuel conditioning system at
present, it is particularly important to build a mathematical model
for the fuel conditioning system. The aeroengine fuel conditioning
system mainly comprises three parts, i.e. a fuel pump, a mechanical
hydraulic device and a fuel dispenser, wherein the mechanical
hydraulic device includes a metering valve, a differential pressure
valve, an oil return valve and other precision components, and has
the disadvantages of complex structure, long design and
manufacturing cycles and high costs, so it is necessary to model
and simulate the mechanical hydraulic device of the fuel
conditioning system to shorten the development cycle and save
costs. By means of modeling simulation, on the one hand, the
performance of the original scheme can be predicted, the advantages
and disadvantages of the scheme can be evaluated, the defects in
the system design can be found and corrected early, and the best
design scheme can be determined; and on the other hand, the
direction of improvement and modification and optimization can be
determined, the product development cycle can be shortened, and the
danger of field test can be effectively avoided. The built model
and the simulation result thereof can not only be used as a
reference when testing and debugging the mechanical hydraulic
device of the fuel conditioning system, but also provide a
reference for the innovative design of the product. The built
real-time model can be further used for hardware-in-the-loop
simulation of aeroengine control systems. Therefore, it is
necessary to study the modeling and simulation of the mechanical
hydraulic device of the engine fuel conditioning system.
[0004] According to the existing literature, modeling and
simulation performed on the mechanical hydraulic device of the
engine fuel conditioning system are mainly performed on an AMESim
platform. Compared with the MATLAB/Simulink platform, the AMESim
platform has the advantage that the mechanical hydraulic device
model built thereon is more intuitive, but has the disadvantage
that the simulation calculation speed far less than Simulink.
Because various components in the mechanical hydraulic device
affect each other, modeling in Simulink involves a complex
double-layered nested algebraic loop problem. By means of the
present invention, the mechanical hydraulic device of the
aeroengine fuel conditioning system in MATLAB/Simulink is modeled
using an analytical method according the structure and flow
continuity of the components and the force balance principle, and
is simulated. Meanwhile, the high precision simulation of the
system is implemented by resolving the double-layered algebraic
loop in the model using the method of inserting high frequency
delay in the feedback loop.
SUMMARY
[0005] In order to implement high speed and high precision
simulation of a mechanical hydraulic device of an aeroengine fuel
conditioning system and solve the problem of a double-layered
nested algebraic loop occurring in modeling and simulation of the
mechanical hydraulic device of the fuel conditioning system, the
present invention provides a Simulink modeling method for a
mechanical hydraulic device of an aeroengine fuel regulator.
[0006] The technical solution of the present invention is as
follows: A Simulink modeling method for a mechanical hydraulic
device of an aeroengine fuel regulator, comprising the following
steps:
[0007] S1. modeling a main differential pressure control loop of a
mechanical hydraulic device of an engine fuel conditioning system
using an analytical method, the main differential pressure control
loop including a metering valve, an oil return valve and a
differential pressure valve;
[0008] modeling the main differential pressure control loop of the
mechanical hydraulic device comprises the following steps:
[0009] S1.1. first, determining input and output parameters of the
metering valve, the input parameters including metering valve flow
Qjiliang, metering valve expected displacement ExDisp, fuel density
Density and after metering valve fuel pressure Pout_JL, and the
output parameters including metering valve displacement Disp, fore
metering valve fuel pressure Pin_JL and metering valve flow
FUEL_Supply;
[0010] S1.2. since the metering valve internally includes a
displacement calculation module and a pressure calculation module,
inputting the metering valve expected displacement ExDisp into the
displacement calculation module, obtaining a current input signal
of an electrohydraulic servo valve through PID control, obtaining
an output flow according to input and output characteristics of the
electrohydraulic servo valve, obtaining a moving speed of the
metering valve by dividing the output flow by area, and obtaining
displacement of the valve through the integral link; and for the
pressure calculation module, according to the mass flow
formula:
Q = .mu. .times. .times. A .times. .DELTA. .times. .times. P * 2
.times. .rho. ##EQU00001## obtaining ##EQU00001.2## Pin_JL = Q 2
.mu. 2 .times. A 2 * 1 2 .times. .rho. + Pout_JL ##EQU00001.3##
[0011] where Q represents fuel mass flow of the metering valve, u
represents flow coefficient, A represents flow area of the metering
valve, .DELTA.P represents difference between fore and after
metering valve pressures, and .rho. represents fuel density;
[0012] S1.3. determining input and output parameters of the oil
return valve, the input parameters including after gear pump fuel
pressure P.sub.1, output fuel pressure P.sub.2 of the differential
pressure valve, after stopping valve fuel pressure P.sub.2P, fuel
supply quantity Q_chilunbeng of the gear pump and fuel density
Density, and the output parameters including fuel return quantity
Q_huiyou of the oil return valve, oil return valve displacement X,
and metering valve flow Q_jiliang;
[0013] S1.4. since the oil return valve internally includes a
displacement calculation module and a flow calculation module,
calculating the displacement according to the following calculation
formula:
X=X.sub.1+X.sub.2
[0014] where x represents displacement of the oil return valve,
X.sub.1 represents displacement of a left spring of the oil return
valve, and X.sub.2 represents displacement of an intermediate
spring of the oil return valve, for the left spring,
P.sub.1*A.sub.1+P.sub.2P*A.sub.2-P.sub.2P*A.sub.3-P.sub.2*A.sub.4=K.sub.-
2*(X.sub.2+X.sub.20)
[0015] and for the intermediate spring,
P.sub.1*A.sub.5-P.sub.2P*A.sub.5=K.sub.1*(X.sub.1+X.sub.10)
[0016] where P.sub.1 represents fore metering valve fuel pressure,
that is, after gear pump fuel pressure; A.sub.1 represents area of
action of fuel of the gear pump, and P.sub.2P represents after
stopping valve fuel pressure; A.sub.2 represents left area of
action of a left spring chamber, A.sub.3 represents right area of
action of the intermediate spring, P.sub.2 represents output fuel
pressure of the differential pressure valve, A.sub.4 represents
area of action of the left spring chamber, A.sub.5 represents
equivalent area of action of the intermediate spring, K.sub.1
represents stiffness coefficient of the intermediate spring,
X.sub.10 represents initial compression amount of the intermediate
spring, K.sub.2 represents stiffness coefficient of the left
spring, and X.sub.20 represents initial compression amount of the
left spring;
[0017] S1.5. calculating the flow area of the oil return valve
through the total displacement of the oil return valve output by
the displacement calculation module, then substituting same into
the mass flow formula to obtain the fuel return quantity of the oil
return valve, and subtracting the fuel return quantity from the
after total flow of the gear pump to obtain the fuel flow of the
metering valve;
[0018] S1.6. determining input and output parameters of the
differential pressure valve, the input parameters including after
gear pump fuel pressure P.sub.1 and spring chamber fuel pressure
P_tanhuangqiang of the differential pressure valve, and the output
parameter including fuel pressure P.sub.2 of control fuel the
differential pressure valve;
[0019] S1.7. performing calculation on the differential pressure
valve mainly using the spring compression module and the pressure
calculation module, wherein the mathematical model of the spring
compression module is:
P.sub.1*S.sub.1+P.sub.tan*(S.sub.4-S.sub.2-S.sub.3)+P.sub.2*S.sub.5+*(X--
0.0001)*(X.gtoreq.0.0001)+f.sub.10-f.sub.20=(K.sub.1+K.sub.2)*X
[0020] where P.sub.tan represents spring chamber fuel pressure of
the differential pressure valve, f.sub.10 represents pretightening
force of bellows of the differential pressure valve, f.sub.20
represents pretightening force of spring of the differential
pressure valve, S.sub.1 represents area of action of fuel of the
bellows, S.sub.2 represents area of action of fuel of the spring
chamber, S.sub.3 represents area of action of low pressure fuel at
the upper end of a nozzle baffle, S.sub.4 represents area of action
of low pressure fuel at the lower end of the nozzle baffle, S.sub.5
represents area of action of the control fuel, K.sub.2 represents
stiffness coefficient of the spring, K.sub.1 represents stiffness
coefficient of the bellows, and the main modeling basis of the
pressure calculation module is the following partial pressure
formula:
P 2 = S 6 2 * P 1 + S 7 2 * P tan S 6 2 + S 7 2 ##EQU00002##
[0021] where S.sub.6 represents area of action of fore fuel of the
metering valve, and S.sub.7 represents area of action of fuel of
the spring chamber;
[0022] S1.8. adding a displacement-area interpolation table in the
metering valve and differential pressure valve module, and
according to the structure principle of the metering valve, the oil
return valve and the differential pressure valve, connecting inputs
and outputs of the three valves, to form a main differential
pressure control loop;
[0023] modeling the main fuel circuit of the mechanical hydraulic
device comprises the following steps:
[0024] S1.9. according to the flow direction of the main fuel
circuit, determining the constitution modules of the main fuel
circuit, including a gear pump, an oil return valve, a metering
valve, a high pressure shut-off valve, a throttle nozzle and a
combustion chamber;
[0025] S1.10. according to the flow equation of the main fuel
circuit, determining the flow differential pressure equation of
each module by the backward induction idea of the differential
pressure, and implementing same in Simulink;
[0026] S1.11. in addition to the mass flow equation, the
mathematical model of the high pressure shut-off valve also
includes a displacement calculation module, the pressure of action
of fuel of the upper chamber thereof is:
F I = P B * ( D P 2 - D R 2 ) * .pi. 4 ##EQU00003##
[0027] where P.sub.B represents fuel pressure at inlet of the high
pressure shut-off valve, D.sub.P represents diameter of upper
chamber of the valve, D.sub.R represents rod diameter of upper
chamber of the valve, and in the equilibrium state, the fuel
pressure and spring force satisfy the following equation:
F.sub.I=P.sub.sp*A.sub.L+K.sub.s*X+F.sub.0
[0028] where A.sub.L represents area of action of fuel of the
spring chamber, P.sub.sp represents fuel pressure of the spring
chamber, F.sub.0 represents pretightening force of the spring,
K.sub.s represents stiffness coefficient of the spring, x
represents displacement of the spring, that is, displacement of the
high pressure shut-off valve, obtaining the flow area of the high
pressure shut-off valve through the displacement-area interpolation
table, and feeding same back to the mass flow equation of the
pressure calculation module;
[0029] modeling other components of the mechanical hydraulic device
comprises the following steps:
[0030] S1.12. selecting a Switch module to switch the operating
state of the stopping valve: if the input signal of the stopping
valve is 0, outputting low pressure fuel to the spring chamber of
the high pressure shut-off valve, so the high pressure shut-off
valve opens and the engine operates normally; and if the input
signal of the stopping valve is greater than 0, outputting high
pressure fuel to the spring chamber of the high pressure shut-off
valve, so the high pressure shut-off valve closes and the fuel
conditioning system stops;
[0031] S1.13. selecting the Switch module to switch the operating
state of an overturn protection device: if the overshoot signal is
0, that is, the engine normally operates, and the overturn
protection device does not operate, directly inputting the after
control fuel of a switch valve to the spring chamber of the
differential pressure valve; and if the engine overturns and the
overshoot signal is not 0, introducing, by the overturn protection
device, the low pressure fuel into the spring chamber of the
differential pressure valve, so the flow of the metering valve is
reduced, and the overturn protection function is achieved;
[0032] S1.14. selecting the Switch module to switch the operating
state of the switch valve: in the case of non-stopping state, both
the upper chamber and lower chamber of the switch valve are in
communication with the fuel tank, thereby outputting low pressure
fuel to the spring chamber of the differential pressure valve; and
in the case of stopping state, the lower chamber of the switch
valve is in communication with the high pressure fuel, and at this
moment, according to the partial pressure formula, by the same as
the partial pressure principle as the differential pressure valve,
the output fuel pressure of the switch valve is obtained;
[0033] S2. modeling the main fuel circuit for fuel of the
mechanical hydraulic device, that is, the fuel circuit from the
gear pump to the fuel dispenser through the metering valve, the
high pressure shut-off valve and the throttle nozzle, according to
the pressure backward induction idea;
[0034] S3. after modeling the main differential pressure control
loop and the main fuel circuit, continuing to build models for
other components of the mechanical hydraulic device in Simulink,
including the stopping valve and the switch valve;
[0035] S4. for the double-layered nested algebraic loops occurring
in model simulation, resolving the algebraic loops using the method
of inserting high frequency delay, and thus improving the model
simulation speed and precision;
[0036] resolving the double-layered nested algebraic loops in the
model comprises the following steps:
[0037] S4.1. inserting high-frequency delay in the form of
G .function. ( s ) 1 + G .function. ( s ) ##EQU00004##
in the inner layer feedback loop of the high pressure shut-off
valve, where
G .function. ( s ) = k 1 * 1 s , ##EQU00005##
and setting a parameter k.sub.1 to make the high pressure shut-off
valve output a correct result;
[0038] S4.2. inserting high-frequency delay in the form of
G .function. ( s ) 1 + G .function. ( s ) ##EQU00006##
in the inner layer feedback loop of the differential pressure
valve, where
G .function. ( s ) = k 2 * 1 s , ##EQU00007##
and setting a parameter k.sub.2 to make the differential pressure
valve output a correct result;
[0039] S4.3. inserting high-frequency delay in the form of
G .function. ( s ) 1 + G .function. ( s ) ##EQU00008##
in the outer layer control loop of the metering valve, where
G .function. ( s ) = k 3 * 1 s , ##EQU00009##
and setting a parameter k.sub.3 to make the control loop of the
metering valve output a correct result;
[0040] S4.4. adjusting the parameters k.sub.1, k.sub.2, k.sub.3 so
that the inner layer frequency of the algebraic loop is higher than
the outer layer frequency, to achieve resolving of the
double-layered nested algebraic loops, and adjusting the parameters
to the state where the system operates stably and outputs a correct
result;
[0041] S5. according to the field test data, correcting the PID
module in the model and system input and output to achieve high
precision simulation of the mechanical hydraulic device of the
aeroengine fuel conditioning system.
[0042] The present invention has the advantageous effects that: the
Simulink modeling method for a mechanical hydraulic device of an
aeroengine fuel regulator proposed by present invention can
implement high precision simulation of the mechanical hydraulic
device of the engine fuel conditioning system, and greatly increase
the simulation speed as compared with the existing modeling
simulation in AMESim; solve the problem of a double-layered nested
algebraic loop occurring when modeling in Simulink, and improve the
simulation precision of the system. In addition, because of having
certain universality, the resolving method for a double-layered
nested algebraic loop can be generalized to resolve other types of
algebraic loops. Meanwhile, the parameters of the simulation model
provided by the present invention can be conveniently modified, and
can provide a reference for modeling simulation of mechanical and
hydraulic devices of engine fuel conditioning systems of other
types.
DESCRIPTION OF DRAWINGS
[0043] FIG. 1 is a schematic diagram showing a modeling mechanism
for a main control loop of a mechanical hydraulic device of an
aeroengine fuel conditioning system;
[0044] FIG. 2 is a schematic diagram showing a modeling mechanism
for a main fuel circuit of a mechanical hydraulic device of an
aeroengine fuel conditioning system;
[0045] FIG. 3 is a schematic diagram showing a resolving method for
a double-layered nested algebraic loop of a Simulink model of a
mechanical hydraulic device of an aeroengine fuel conditioning
system;
[0046] FIG. 4 is a waveform diagram showing oscillation of a
double-layered nested algebraic loop; and
[0047] FIG. 5 is a waveform diagram showing a resolving effect of a
double-layered nested algebraic loop.
DETAILED DESCRIPTION
[0048] The present invention is further described below in
combination with the drawings. A Simulink modeling method for a
mechanical hydraulic device of an aeroengine fuel regulator,
comprising the following steps:
[0049] S1. modeling a main differential pressure control loop of a
mechanical hydraulic device of an engine fuel conditioning system
using an analytical method, the main differential pressure control
loop including a metering valve, an oil return valve and a
differential pressure valve;
[0050] S2. modeling the main fuel circuit for fuel of the
mechanical hydraulic device, that is, the fuel circuit from the
gear pump to the fuel dispenser through the metering valve, the
high pressure shut-off valve and the throttle nozzle, according to
the pressure backward induction idea;
[0051] S3. after modeling the main differential pressure control
loop and the main fuel circuit, continuing to build models for
other components of the mechanical hydraulic device in Simulink,
including the stopping valve and the switch valve;
[0052] S4. for the inner layer algebraic loop of the high pressure
shut-off valve, the inner layer algebraic loop of the differential
pressure valve and the outer layer algebraic loop of the control
loop of the metering valve, resolving the algebraic loops using the
method of inserting high frequency delay, and thus improving the
model simulation speed and precision;
[0053] S5. according to the field test data, correcting the PID
module in the model and system input and output to achieve high
precision simulation of the mechanical hydraulic device of the
aeroengine fuel conditioning system;
[0054] wherein as shown in FIG. 1, modeling the main differential
pressure control loop of the mechanical hydraulic device comprises
the following steps:
[0055] S1. first, determining input and output parameters of the
metering valve, the input parameters including metering valve flow
Qjiliang, metering valve expected displacement ExDisp, fuel density
Density and after metering valve fuel pressure Pout_JL, and the
output parameters including metering valve displacement Disp, fore
metering valve fuel pressure Pin_JL and metering valve flow
FUEL_Supply;
[0056] S2. since the metering valve internally includes a
displacement calculation module and a pressure calculation module,
making a difference, by the displacement calculation module,
between the input metering valve expected displacement ExDisp and
the displacement feedback signal, obtaining a current input signal
of an electrohydraulic servo valve through linear transformation
and PID control, calculating the output flow according to the
proportional relationship between the input and output of the
electrohydraulic servo valve, converting the output flow into
volume flow, obtaining a moving speed of the metering valve by
dividing the volume flow by area, obtaining displacement of the
valve through the integral link, modeling, by the pressure
calculation module, mainly based on the mass flow formula
Q=.mu.A {square root over (.DELTA.P*2.rho.)}
[0057] and according to the mass flow formula, obtaining:
Pin_JL = Q 2 .mu. 2 .times. A 2 * 1 2 .times. .rho. + Pout_JL
##EQU00010##
[0058] where Q represents fuel mass flow of the metering valve,
flow coefficient .mu.=0.71, A represents flow area of the metering
valve, .DELTA.P represents difference between fore and after
metering valve pressures, fuel density .mu.=780 kg/m.sup.3, Pin_JL
represents fore metering valve fuel pressure, and Pout_JL
represents after metering valve fuel pressure;
[0059] S3. determining input and output parameters of the oil
return valve, the input parameters including after gear pump fuel
pressure P.sub.1, after differential pressure valve fuel pressure
P.sub.2, after switch valve fuel pressure P.sub.2P, and the fuel
supply quantity Q_chilunbeng of the gear pump and fuel density
Density, and the output parameters including fuel return quantity
Q_huiyou of the oil return valve, oil return valve displacement X,
and metering valve flow Q_jiliang;
[0060] S4. calculating the displacement of the oil return valve
according to the formula as follows:
X=X.sub.1+X.sub.2
[0061] where X represents total displacement of the oil return
valve, X.sub.1 represent displacement of a left spring of the oil
return valve, and X.sub.2 represent displacement of an intermediate
spring of the oil return valve, for the left spring,
P.sub.1*A.sub.1+P.sub.2P*A.sub.2-P.sub.2P*A.sub.3-P.sub.2*A.sub.4=K.sub.-
2*(X.sub.2+X.sub.20)
[0062] and for the intermediate spring,
P.sub.1*A.sub.5-P.sub.2P*A.sub.5=K.sub.1*(X.sub.1+X.sub.10)
[0063] where P.sub.1 represents fore metering valve fuel pressure,
i.e. after gear pump fuel pressure, A.sub.1 represents area of
action of fuel of the gear pump, P.sub.2P represents after stopping
valve fuel pressure, A.sub.2 represents left area of action of a
left spring chamber, A.sub.3 represents right area of action of the
intermediate spring, P.sub.2 represents output fuel pressure of the
differential pressure valve, A.sub.4 represents area of action of
the left spring chamber, A.sub.5 represents equivalent area of
action of the intermediate spring, K.sub.1 represents stiffness
coefficient of the intermediate spring, X.sub.10 represents initial
compression amount of the intermediate spring, K.sub.2 represents
stiffness coefficient of the left spring, and X.sub.20 represents
initial compression amount of the left spring;
[0064] S5. calculating the flow area of the oil return valve
through the total displacement of the oil return valve output by
the displacement calculation module, then substituting same into
the mass flow formula to obtain the fuel return quantity of the oil
return valve, and subtracting the fuel return quantity from the
after total flow of the gear pump to obtain the fuel flow of the
metering valve;
[0065] S6. determining input and output parameters of the
differential pressure valve, the input parameters including after
gear pump fuel pressure P.sub.1 and spring chamber fuel pressure
P_tanhuangqiang of the differential pressure valve, and the output
parameter including fuel pressure P.sub.2 of control fuel of the
differential pressure valve;
[0066] S7. performing calculation on the differential pressure
valve mainly using the spring compression module and the pressure
calculation module, wherein the mathematical model of the spring
compression module is:
P.sub.1*S.sub.1+P.sub.tan*(S.sub.4-S.sub.2-S.sub.3)+P.sub.2*S.sub.5+*(X--
0.0001)*(X.gtoreq.0.0001)+f.sub.10-f.sub.20=(K.sub.1+K.sub.2)*X
[0067] where P.sub.tan represents spring chamber fuel pressure of
the differential pressure valve, f.sub.10 represents pretightening
force of bellows of the differential pressure valve, f.sub.20
represents pretightening force of spring of the differential
pressure valve, S.sub.1 represents area of action of fuel of the
bellows, S.sub.2 represents area of action of fuel of the spring
chamber, S.sub.3 represents area of action of low pressure fuel at
the upper end of a nozzle baffle, S.sub.4 represents area of action
of low pressure fuel at the lower end of the nozzle baffle, S.sub.5
represents area of action of the control fuel, K.sub.2 represents
stiffness coefficient of the spring, K.sub.1 represents stiffness
coefficient of the bellows, and the main modeling basis of the
pressure calculation module is the following partial pressure
formula:
P 2 = S 6 2 * P 1 + S 7 2 * P tanh .times. .times. uangqiang S 6 2
+ S 7 2 ##EQU00011##
[0068] where S.sub.6 represents area of action of fore fluid of the
metering valve, and S.sub.7 represents area of action of fuel of
the spring chamber;
[0069] S8. adding a displacement-area interpolation table in the
metering valve and differential pressure valve module of the main
differential pressure loop, wherein in the metering valve, the
displacement-area interpolation table converts the displacement of
the valve spool of the metering valve into the flow area of the
valve, and in the differential pressure valve, the
displacement-area interpolation table converts the compression
amount of the spring of the differential pressure valve into the
area of action of fuel of the nozzle baffle valve; then, according
to the relationship between inputs and outputs of the metering
valve, the oil return valve and the differential pressure valve,
connecting the three valves, to form a main differential pressure
control loop;
[0070] as shown in FIG. 2, modeling the main fuel circuit of the
mechanical hydraulic device comprises the following steps:
[0071] S1. according to the flow direction of the main fuel
circuit, determining the constitution modules of the main fuel
circuit, including a gear pump, an oil return valve, a metering
valve, a high pressure shut-off valve, a throttle nozzle and a
combustion chamber;
[0072] S2. according to the mass flow equation, determining the
flow differential pressure equation of each module by the backward
induction idea of the differential pressure, and implementing same
in Simulink;
[0073] S3. in addition to the mass flow equation, the mathematical
model of the high pressure shut-off valve also includes a
displacement calculation module, the pressure of action of fuel of
the upper chamber thereof is:
F I = P B * ( D P 2 - D R 2 ) * .pi. 4 ##EQU00012##
[0074] where P.sub.B represents fuel pressure at inlet of the high
pressure shut-off valve, D.sub.P represents diameter of upper
chamber of the valve, D.sub.R represents rod diameter of upper
chamber of the valve, and in the equilibrium state, the fuel
pressure and spring force satisfy the following equation:
F.sub.I=P.sub.sp*A.sub.L+K.sub.s*X+F.sub.0
[0075] where A.sub.L represents area of action of fuel of the
spring chamber, P.sub.sp represents fuel pressure of the spring
chamber, F.sub.0 represents pretightening force of the spring,
K.sub.s represents stiffness coefficient of the spring, X
represents displacement of the spring, that is, displacement of the
high pressure shut-off valve, obtaining the flow area of the high
pressure shut-off valve through the displacement-area interpolation
table, and feeding same back to the mass flow equation of the
pressure calculation module;
[0076] modeling other components of the mechanical hydraulic device
comprises the following steps:
[0077] S1. selecting a Switch module to switch the operating state
of the stopping valve: if the input signal of the stopping valve is
0, outputting low pressure fuel to the spring chamber of the high
pressure shut-off valve, so the high pressure shut-off valve opens
and the engine operates normally; and if the input signal of the
stopping valve is greater than 0, outputting high pressure fuel to
the spring chamber of the high pressure shut-off valve, so the high
pressure shut-off valve closes and the fuel conditioning system
stops;
[0078] S2. selecting the Switch module to switch the operating
state of an overturn protection device: if the overshoot signal is
0, that is, the engine normally operates, and the overturn
protection device does not operate, directly inputting the after
control fuel of a switch valve to the spring chamber of the
differential pressure valve; and if the overshoot signal is not 0
and the engine overturns, introducing, by the overturn protection
device, the low pressure fuel into the spring chamber of the
differential pressure valve, so the flow of the metering valve is
reduced, and the overturn protection function is achieved;
[0079] S3. selecting the Switch module to switch the operating
state of the switch valve: in the case of non-stopping state, both
the upper chamber and lower chamber of the switch valve are in
communication with the fuel tank, thereby outputting low pressure
fuel to the spring chamber of the differential pressure valve; and
in the case of stopping state, the lower chamber of the switch
valve is in communication with the high pressure fuel, and at this
moment, according to the partial pressure formula, the calculation
method for the output fuel pressure of the switch valve is as
follows:
P switch = S 8 2 * Pcb + S 9 2 * Psp S 8 2 + S 9 2 ##EQU00013##
[0080] where P.sub.switch represents output fuel pressure of the
switch valve, S.sub.8 represents throttle area of the upper chamber
of the switch valve, S.sub.9 represents throttle area of the lower
chamber of the switch valve, Pcb represents fuel pressure of a low
pressure fuel tank which is in communication with the upper chamber
of the switch valve, and Psp represents fuel pressure of high
pressure fuel of the output of the stopping valve in the stopping
state, the output of the stopping valve being in communication with
the lower chamber of the switch valve;
[0081] as shown in FIG. 3, resolving the double-layered nested
algebraic loops in the model comprises the following steps:
[0082] S1. inserting high-frequency delay in the form of
G .function. ( s ) 1 + G .function. ( s ) ##EQU00014##
in the inner layer feedback loop of the high pressure shut-off
valve, where
G .function. ( s ) = k 1 * 1 s , ##EQU00015##
and setting a parameter k.sub.1=1000 to make the high pressure
shut-off valve output a correct result;
[0083] S2. inserting high-frequency delay in the form of
G .function. ( s ) 1 + G .function. ( s ) ##EQU00016##
in the inner layer feedback loop of the differential pressure
valve, where
G .function. ( s ) = k 2 * 1 s , ##EQU00017##
and setting a parameter k.sub.2=1000 to make the differential
pressure valve output a correct result;
[0084] S3. inserting high-frequency delay in the form of
G .function. ( s ) 1 + G .function. ( s ) ##EQU00018##
in the outer layer control loop of the metering valve, where
G .function. ( s ) = k 3 * 1 s , ##EQU00019##
and setting a parameter k.sub.3=200 to make the control loop of the
metering valve output a correct result;
[0085] S4. resolving the double-layered nested algebraic loops
since the parameters k.sub.1, k.sub.2, and k.sub.3 meet the
requirement that the inner layer frequency of the algebraic loop is
higher than the outer layer frequency, wherein the waveform of the
system oscillation caused by the double-layered nested algebraic
loop is shown in FIG. 4, and the system output waveform after
resolving the algebraic loop by inserting high frequency delay is
shown in FIG. 5, and finally adjusting the parameters to the state
where the system operates stably and outputs a correct result.
[0086] To sum up, the modeling method for a mechanical hydraulic
device of an aeroengine fuel regulator based on Simulink proposed
by the present invention is feasible, which can achieve the high
speed and high precision simulation of the mechanical hydraulic
device of the aeroengine fuel conditioning system, and can solve
the problem of a double-layered nested algebraic loop in modeling
simulation.
* * * * *