CN110040141A - A kind of crawling mode pump displacement control optimal based on overall efficiency - Google Patents
A kind of crawling mode pump displacement control optimal based on overall efficiency Download PDFInfo
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- 230000009193 crawling Effects 0.000 title claims abstract description 45
- 238000006073 displacement reaction Methods 0.000 title claims abstract description 22
- 238000004422 calculation algorithm Methods 0.000 claims abstract description 7
- 239000003921 oil Substances 0.000 claims description 8
- 238000005457 optimization Methods 0.000 claims description 7
- 238000004364 calculation method Methods 0.000 claims description 6
- 239000000446 fuel Substances 0.000 claims description 4
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- 239000010705 motor oil Substances 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 8
- 230000004044 response Effects 0.000 description 7
- 230000005540 biological transmission Effects 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 239000010720 hydraulic oil Substances 0.000 description 2
- 230000009347 mechanical transmission Effects 0.000 description 2
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- 235000005035 Panax pseudoginseng ssp. pseudoginseng Nutrition 0.000 description 1
- 235000003140 Panax quinquefolius Nutrition 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
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- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000005183 dynamical system Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 235000008434 ginseng Nutrition 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W10/00—Conjoint control of vehicle sub-units of different type or different function
- B60W10/04—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units
- B60W10/06—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units including control of combustion engines
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W10/00—Conjoint control of vehicle sub-units of different type or different function
- B60W10/30—Conjoint control of vehicle sub-units of different type or different function including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
- B60W30/18—Propelling the vehicle
- B60W30/18009—Propelling the vehicle related to particular drive situations
- B60W30/18063—Creeping
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W2710/00—Output or target parameters relating to a particular sub-units
- B60W2710/06—Combustion engines, Gas turbines
- B60W2710/0644—Engine speed
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W2710/00—Output or target parameters relating to a particular sub-units
- B60W2710/06—Combustion engines, Gas turbines
- B60W2710/0666—Engine torque
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W2710/00—Output or target parameters relating to a particular sub-units
- B60W2710/09—Other types of propulsion units, e.g. fluid motors, or type not specified
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Abstract
The invention discloses a kind of crawling mode pump displacement control optimal based on overall efficiency, this method, which aims to solve the problem that, controls variable pump discharge capacity to coordinate engine control guarantee system overall efficiency optimal problem when wheel hub hydraulic car is in crawling mode.The present invention is based on wheel hub hydraulic hybrid power systems, according to current crawling speed, it determines hydraulic system swash plate aperture, and then solves and obtain the engine working point under corresponding aperture, utilize the optimal swash plate aperture of golden cut algorithm iterative search and engine optimum operating point.This method the following steps are included: one, determine the variable pump swash plate aperture region of search；Two, engine demand power determines；Three, engine working point is found；Four, target optimizing function is arranged；Five, iteration optimizing solves.
Description
Technical field
The present invention relates to a kind of crawling mode pump displacement control optimal based on overall efficiency, more precisely, this
Invention is related to a kind of wheel hub hydraulic variable displacement pump displacement control.
Background technique
Different from oily electric-type hybrid power system, wheel hub hydraulic hybrid power system is a kind of typical strong nonlinearity, ginseng
The mechanical electronic hydraulic coupling control system of number time-varying, the response characteristic difference of front-wheel hydraulic transmission part and middle rear-wheel mechanical transmission component
Obviously, while by heavy type commercial vehicle complexity operating condition and load wide variation feature it is influenced, wheel hub is hydraulic mixed
The dynamic Control platform for closing dynamical system is difficult to ensure, on the one hand, the driving between Hydraulic Power Transmission System and machine driven system
Power control is also easy to produce interference, influences the performance of system assist function；On the other hand, hydraulic system essentially nonlinear problem is also easy
The lag or overshoot for causing hydraulic execution unit control cause hydraulic system response relatively slow or generate biggish compression shock, shadow
Acoustic system dynamic control performance.
When the research of front hub hydraulic hybrid power system at home still in its infancy, around the system carry out it is careful
Scheme optimization and core control algolithm exploitation etc. key technologies theoretical research theory significance still with higher and application value,
Current to still have following technological difficulties problem for wheel hub hydraulic hybrid power system: wheel hub hydraulic hybrid power system moves
State Control platform is influenced by system nature's nonlinear Control feature, while hydraulic drive path and each component of mechanical transmission path
Dynamic response characteristic difference is obvious；The problem of wheel hub hydraulic hybrid power system multi-mode energy management simultaneously is complicated, due to vehicle
The uncertainty of external operating condition and the different response characteristic of different working modes, so that realizing system operating mode and work
The Optimized Matching difficulty of condition increases.
Existing some patents, if China Patent Publication No. is CN103660915A, publication date is on March 26th, 2014,
Entitled " a kind of hub hydraulic motor driving system variable pump displacement control ", which proposes that a kind of wheel hub is hydraulic
Variable method for controlling pump is driven, he can guarantee that vehicle guarantees that vehicle trackslips when through low attachment road surface or great slope road surface
Efficiency optimization.China Patent Publication No. is CN105502191A, and publication date is on April 20th, 2016, a kind of entitled " rotation
Dig discharge of main pump control method in the lifting process of drilling machine master winch interflow ", invention proposition will fall rate as falling fast state
Judge parameter, when pawning rate less than setting value, without adjusting, when pawning rate and being greater than the set value, is adjusted by real-time PID
The input current value of proportional pressure-reducing valve, to control the discharge capacity of main pump.
In conclusion the existing patent in terms of wheel hub hydraulic variable displacement pump displacement control, carries out wheel hub using software
Model buildings, at the same utilize simple control algolithm, due to by build model limited with Utopian software runtime environment,
So that simulation result excessively idealizes, reality may not apply to.Therefore, it is necessary to provide, one kind is perfect, reliable wheel hub is hydraulic
Variable pump displacement control makes up the deficiencies in the prior art, guarantees under system different working modes hydraulic system and mechanical is
The dynamic compatibility of system, and guarantee hydraulic execution unit can optimal control target under each mode of good response, improve wheel hub liquid
Press the dynamic Control platform of hybrid power system.
Summary of the invention
Present invention seek to address that it is negative to meet vehicle traveling to control variable pump discharge capacity when wheel hub hydraulic car is in crawling mode
Load demand and coordinates engine control and ensure that engine and Hydraulic Power Transmission System work the high efficient district the problem of, propose one kind
Based on the crawling mode pump displacement control that overall efficiency is optimal, it is based on current crawling speed, determines that hydraulic system swash plate is opened
Degree, and then solve and obtain the engine working point under corresponding aperture, utilize the optimal swash plate aperture of golden cut algorithm iterative search
With engine optimum operating point.
In order to solve the above technical problems, the present invention is achieved by the following technical scheme:
A kind of crawling mode pump displacement control optimal based on overall efficiency, comprising the following steps:
Step 1: the pump swash plate aperture region of search determines, according to current vehicle crawling speed, demand function at wheel is determined
Rate solves to obtain wheel hub hydraulic motor rotary speed according to flow agreement principle, in combination with current closed circuit hydraulic pressure difference,
Determine the region of search of variable pump swash plate aperture；
According to flow agreement principle, the flow of two wheel hub hydraulic motors is equal to variable pump output stream under crawling mode
Amount, as shown in formula (1):
ωpβVpmaxηpvηvv=2 ωmVm/ηmv (1)
In formula, ωp、ωmRespectively indicate hydraulic variable flow revolution speed and wheel hub hydraulic motor rotary speed, ηvvTabular form hydraulic control
The loss in efficiency of valve group and pipeline；
At this point, wheel hub hydraulic motor rotary speed ωmWith hydraulic variable displacement pump rotational speed omegapBetween meet relationship:
Meanwhile calculate two front-wheel hub hydraulic motors output torque and, as shown in formula (3):
Further, the output power for obtaining wheel hub hydraulic motor at wheel, as shown in formula (4):
In addition, being attached between engine and variable pump by PTO in wheel hub hydraulic hybrid power system, therefore start
Meet following relationship between machine revolving speed and variable revolution speed:
ωp=ωe/ip (5)
In formula, ωeIndicate engine speed, ipIndicate PTO speed ratio；
Therefore, the output power of hydraulic motor and oil circuit pressure difference Δ P and present engine rotational speed omega at wheelePass
System, as shown in formula (6):
As it can be seen that the power output of crawling mode lower hub hydraulic motor depends primarily on variable pump swash plate aperture β, hydraulic oil
Road pressure differential Δ P and engine speed ωe, wherein oil circuit pressure depends primarily on the load torque of front-wheel, when vehicle is compacted
In the case that target vehicle speed of travel under row mode determines, vehicle driving demand power and demand torque can be corresponding at this time
It determines, and then can determine the hydraulic circuit pressure differential Δ P of current demand, then the relationship according to shown in formula (6), by adjusting
The i.e. adjustable engine speed ω of the discharge capacity (i.e. swash plate aperture β) of variable pumpeOperation interval；
Based on the crawling speed of operation v arbitrarily allowedcreep, the demand power P at front vehicle wheel is being determinedcreep, wheel hub
Hydraulic motor rotary speed ωmAnd after closed circuit hydraulic pressure difference Δ P, it may further determine that the search of variable pump swash plate aperture
Section is according to the optimized rotating speed section [ω of enginee,opt,min,ωe,opt,max], convolution (2) can determine under crawling mode
The minimum swash plate aperture β of the variable pump of corresponding current crawling speedcreep,minWith maximum swash plate aperture βcreep,max, such as formula (7) institute
Show:
And then it can determine the corresponding pump swash plate aperture region of search, [β under current crawling speedcreep,min,…,
βcreep,n,…,βcreep,max]。
Step 2: engine demand power determines, corresponding arbitrary pump swash plate aperture and the hydraulic pressure of current closed circuit
Power is poor, in conjunction with the efficiency calculation formula of variable pump and wheel hub hydraulic motor, obtains when corresponding engine under front pump swash plate aperture
Demand power；
Using the efficiency calculation formula of variable pump and wheel hub hydraulic motor, it is calculated when the corresponding liquid of front pump swash plate aperture
The volumetric efficiency η of pressure variable amount pumpcreep,pv,n, mechanical efficiency ηcreep,pm,nAnd the volumetric efficiency of wheel hub hydraulic motor
ηcreep,mv,n, mechanical efficiency ηcreep,mm,n；And then it obtains when corresponding engine demand power P under front pump swash plate aperturee,req,n,
As shown in formula (8):
Pe,req,n=Pcreep/ηcreep,pv,n/ηcreep,pm,n/ηcreep,mv,n/ηcreep,mm,n (8)
Step 3: engine working point determines, based on when front hub hydraulic motor rotary speed and pump swash plate opening information, solve
The corresponding engine speed of different pump swash plate apertures is obtained, using the demand power in step 2, solution is obtained when front pump swash plate
Aperture corresponding engine speed torque operating point.
Step 4: setting target optimizing function, is based on overall efficiency principle of optimality, choose when front pump swash plate aperture is corresponding
For engine consumption as objective optimization function, the smallest point of objective optimization function is the optimal point of system overall efficiency；
Based on the thought that overall efficiency is optimal, iterative search obtains corresponding optimal pump swash plate aperture under current crawling speed
And optimal engine operating point, it chooses and works as the corresponding engine consumption B of front pump swash plate aperturee,nAs objective function, such as formula
(9) shown in, it is clear that the smallest point of objective function is the optimal point of system overall efficiency, i.e., optimal pumpage control target with
And engine optimum revolving speed, direct torque target；
Fn(βcreep,n)=Be,n=be,nPe,req,n (9)
In formula, be,nIndicate corresponding fuel consumption rate under present engine operating point.
5. a kind of crawling mode pump displacement control optimal based on overall efficiency described in accordance with the claim 1,
It is characterized in that, the step 5 iteration optimizing solution specifically includes the following contents:
The optimizing of golden cut algorithm iteration is utilized according to target optimizing function shown in formula (9), in pump swash plate aperture search
The corresponding optimal pump swash plate aperture of the current crawling speed of rapid solving in section, specific as follows shown:
1) the primary pump swash plate aperture region of search having had determined that, [a (1), b (1)]=[β are selectedcreep,min, 1], setting
Search precision requires tol, golden section coefficient T=0.618, cycle counter initial value k=1；
2) c (k)=a (k)+(1-T) (b (k)-a (k)) is enabled, d (k)=b (k)-(1-T) (b (k)-a (k)) calculates Fc=F
(c (k)), Fd=F (d (k))；Wherein, F indicates target optimizing function；
3) if Fc < Fd, goes to step 4)；Otherwise step 5) is gone to；
4) a (k+1)=a (k), b (k+1)=d (k), d (k+1)=c (k), Fd=Fc are enabled；
It enables c (k+1)=a (k+1)+(1-T) (b (k+1)-a (k+1)), calculates Fc=F (c (k+1)), go to step 6)；
5) a (k+1)=c (k), c (k+1)=d (k), b (k+1)=b (k), Fc=Fd are enabled；
Enable d (k+1)=b (k+1)-(1-T) (b (k+1)-a (k+1))；It calculates Fd=F (d (k+1)), goes to step 6)；
6) k=k+1 is enabled；If meeting b (k)-a (k) >=tol, return step 3 at this time) continue to iterate to calculate, until repeatedly
For numerical convergence；Otherwise it stops search.
Compared with prior art the beneficial effects of the present invention are:
1. being based on overall efficiency principle of optimality, reduce wheel hub hydraulic power system unit response difference characteristic, eliminates hydraulic
System hydraulic volume efficiency bring calculates error, and control effect is more true, can imitate, while guaranteeing Vehicular system whole efficiency
It is optimal, change and improve component riding quality；
2. choosing when the corresponding engine consumption of front pump swash plate aperture is target optimizing function, engine, the variable of acquisition
Pump work point can guarantee that the oil consumption of vehicle reduces, and improves the economic performance of vehicle, improves the energy-saving effect of vehicle；
3. carrying out the iteration optimizing of objective function using golden cut algorithm, the dominated variable region of search simplifies and solves step
Suddenly, accelerate objective function speed of searching optimization, guarantee that calculating acquired results has good robustness, more practicability.
4. being based on wheel hub hydraulic system, the variable pump response characteristic under vehicle crawling mode is analyzed, it is former based on the conservation of energy
Reason and theoretical formula solve obtain variable pump control discharge capacity, for it rear-wheel hub hydraulic car variable pump displacement control provide it is solid can
The theoretical basis leaned on.
Detailed description of the invention
The present invention will be further described below with reference to the drawings:
Fig. 1 is wheel hub hydraulic hybrid power system variable pump displacement control overall flow figure of the present invention；
Fig. 2 is the configuration picture of wheel hub hydraulic hybrid power system of the present invention；
Fig. 3 is that engine working point of the present invention solves flow chart；
Fig. 4 is golden section approach flow chart of the present invention；
Specific embodiment:
The present invention is explained in detail with reference to the accompanying drawing:
Refering to fig. 1, the hydraulic crawling mode pump displacement control of wheel hub of the present invention is divided into five steps: step 1
The swash plate aperture region of search is pumped to determine, based on the crawling speed of operation arbitrarily allowed, the demand at front vehicle wheel is being determined
After power, wheel hub hydraulic motor rotary speed and closed circuit hydraulic pressure difference, variable pump swash plate aperture may further determine that
The region of search；Step 2 is to determine the corresponding engine demand power of pump swash plate aperture, in conjunction with current closed circuit hydraulic pressure
Poor and relevant engine, variable pump volumetric efficiency solve the engine demand power obtained under respective pump swash plate aperture；Step
Rapid three be the determination of engine working point, and based on front hub hydraulic motor rotary speed is worked as, solution obtains corresponding engine speed, application
The engine demand power calculation that step 2 obtains obtains engine demand torque；Step 4 is setting target optimizing function.Base
In complete-vehicle oil consumption principle of optimality, using engine fuel consumption rate as target optimizing function；Step 5 is iteration optimizing solution, benefit
The target optimizing function being arranged with golden cut algorithm solution procedure four, obtains engine optimum operating point and pumpage control is joined
Number.
A kind of crawling mode pump displacement control optimal based on overall efficiency of the present invention, including following step
It is rapid:
Step 1: the pump swash plate aperture region of search determines.
The wheel hub hydraulic pump swash plate aperture region of search determines that content includes: that (1) determines demand power at wheel；(2) it solves
The region of search of wheel hub hydraulic motor rotary speed, (3) variable pump swash plate aperture determines.Specifically include the following contents:
According to flow agreement principle, the flow of two wheel hub hydraulic motors is equal to variable pump output stream under crawling mode
Amount, as shown in formula (10).
ωpβVpmaxηpvηvv=2 ωmVm/ηmv (10)
In formula, ωp、ωmRespectively indicate hydraulic variable flow revolution speed and wheel hub hydraulic motor rotary speed, ηvvTabular form hydraulic control
The loss in efficiency of valve group and pipeline.
At this point, wheel hub hydraulic motor rotary speed ωmWith hydraulic variable displacement pump rotational speed omegapBetween meet relationship:
Meanwhile calculate two front-wheel hub hydraulic motors output torque and, as shown in formula (12):
Further, the output power for obtaining wheel hub hydraulic motor at wheel, as shown in formula (13):
In addition, being attached between engine and variable pump by PTO in wheel hub hydraulic hybrid power system, therefore start
Meet following relationship between machine revolving speed and variable revolution speed:
ωp=ωe/ip (14)
In formula, ωeIndicate engine speed, ipIndicate PTO speed ratio.
Therefore, the output power of hydraulic motor and oil circuit pressure difference Δ P and present engine rotational speed omega at wheelePass
System, as shown in formula (15):
As it can be seen that the power output of crawling mode lower hub hydraulic motor depends primarily on variable pump swash plate aperture β, hydraulic oil
Road pressure differential Δ P and engine speed ωe, wherein oil circuit pressure depends primarily on the load torque of front-wheel, when vehicle is compacted
In the case that target vehicle speed of travel under row mode determines, vehicle driving demand power and demand torque can be corresponding at this time
It determines, and then can determine the hydraulic circuit pressure differential Δ P of current demand, then the relationship according to shown in formula (15), passes through tune
The i.e. adjustable engine speed ω of the discharge capacity (i.e. swash plate aperture β) of integer variable pumpeOperation interval.
Based on the crawling speed of operation v arbitrarily allowedcreep, the demand power P at front vehicle wheel is being determinedcreep, wheel hub
Hydraulic motor rotary speed ωmAnd after closed circuit hydraulic pressure difference Δ P, it may further determine that the search of variable pump swash plate aperture
Section, according to the optimized rotating speed section [ω of enginee,opt,min,ωe,opt,max], convolution (11) can determine crawling mode
The minimum swash plate aperture β of the variable pump of the lower current crawling speed of correspondencecreep,minWith maximum swash plate aperture βcreep,max, such as formula (16)
It is shown.
And then it can determine the corresponding pump swash plate aperture region of search, [β under current crawling speedcreep,min,…,
βcreep,n,…,βcreep,max]。
Step 2: engine demand power determines.Specifically include the following contents:
Using the efficiency calculation formula of variable pump and wheel hub hydraulic motor, it is calculated when the corresponding liquid of front pump swash plate aperture
The volumetric efficiency η of pressure variable amount pumpcreep,pv,n, mechanical efficiency ηcreep,pm,nAnd the volumetric efficiency of wheel hub hydraulic motor
ηcreep,mv,n, mechanical efficiency ηcreep,mm,n；And then it obtains when corresponding engine demand power P under front pump swash plate aperturee,req,n,
As shown in formula (17).
Pe,req,n=Pcreep/ηcreep,pv,n/ηcreep,pm,n/ηcreep,mv,n/ηcreep,mm,n (17)
Step 3: engine working point determines.
Refering to Fig. 3, based on when front hub hydraulic motor rotary speed and pump swash plate opening information, solution obtains different pump swash plates and opens
Corresponding engine speed is spent, using the demand power in step 2, solution is obtained when the corresponding engine of front pump swash plate aperture
Rotational speed and torque operating point.
Step 4: setting target optimizing function.
Based on the thought that overall efficiency is optimal, iterative search obtains corresponding optimal pump swash plate aperture under current crawling speed
And optimal engine operating point, it chooses and works as the corresponding engine consumption B of front pump swash plate aperturee,nAs objective function, such as formula
(18) shown in, it is clear that the smallest point of objective function is the optimal point of system overall efficiency, i.e., optimal pumpage control target with
And engine optimum revolving speed, direct torque target.
Fn(βcreep,n)=Be,n=be,nPe,req,n (18)
In formula, be,nIndicate corresponding fuel consumption rate under present engine operating point；
Step 5: iteration optimizing solves.
In order to accelerate the speed of Optimum search, it is iterated optimizing using Fibonacci method, in the pump swash plate aperture field of search
The corresponding optimal pump swash plate aperture of the interior current crawling speed of rapid solving.Specifically include the following contents:
Referring to Fig. 3, the optimizing of golden cut algorithm iteration is utilized according to target optimizing function shown in (18), is opened in pump swash plate
The corresponding optimal pump swash plate aperture of the current crawling speed of rapid solving in the region of search is spent, specific as follows shown:
1) the primary pump swash plate aperture region of search having had determined that, [a (1), b (1)]=[β are selectedcreep,min, 1], setting
Search precision requires tol, golden section coefficient T=0.618, cycle counter initial value k=1；
2) c (k)=a (k)+(1-T) (b (k)-a (k)) is enabled, d (k)=b (k)-(1-T) (b (k)-a (k)) calculates Fc=F
(c (k)), Fd=F (d (k))；Wherein, F indicates target optimizing function；
3) if Fc < Fd, goes to step 4)；Otherwise step 5) is gone to；
4) a (k+1)=a (k), b (k+1)=d (k), d (k+1)=c (k), Fd=Fc are enabled；
It enables c (k+1)=a (k+1)+(1-T) (b (k+1)-a (k+1)), calculates Fc=F (c (k+1)), go to step 6)；
5) a (k+1)=c (k), c (k+1)=d (k), b (k+1)=b (k), Fc=Fd are enabled；
Enable d (k+1)=b (k+1)-(1-T) (b (k+1)-a (k+1))；It calculates Fd=F (d (k+1)), goes to step 6)；
6) k=k+1 is enabled；If meeting b (k)-a (k) >=tol, return step 3 at this time) continue to iterate to calculate, until repeatedly
For numerical convergence；Otherwise it stops search.
Claims (2)
1. a kind of crawling mode pump displacement control optimal based on overall efficiency, which comprises the following steps:
Step 1: the pump swash plate aperture region of search determines, according to current vehicle crawling speed, demand power at wheel, root are determined
It solves to obtain wheel hub hydraulic motor rotary speed according to flow agreement principle, in combination with current closed circuit hydraulic pressure difference, determine
The region of search of variable pump swash plate aperture；
According to flow agreement principle, the flow of two wheel hub hydraulic motors is equal to variable pump output flow under crawling mode, such as
Shown in formula (1):
ωpβVpmaxηpvηvv=2 ωmVm/ηmv (1)
In formula, ωp、ωmRespectively indicate hydraulic variable flow revolution speed and wheel hub hydraulic motor rotary speed, ηvvTabular form hydraulic control valve group
And the loss in efficiency of pipeline；
At this point, wheel hub hydraulic motor rotary speed ωmWith hydraulic variable displacement pump rotational speed omegapBetween meet relationship:
Meanwhile calculate two front-wheel hub hydraulic motors output torque and, as shown in formula (3):
Further, the output power for obtaining wheel hub hydraulic motor at wheel, as shown in formula (4):
In addition, being attached between engine and variable pump by PTO in wheel hub hydraulic hybrid power system, therefore engine turns
Meet following relationship between speed and variable revolution speed:
ωp=ωe/ip (5)
In formula, ωeIndicate engine speed, ipIndicate PTO speed ratio；
Therefore, the output power of hydraulic motor and oil circuit pressure difference Δ P and present engine rotational speed omega at wheeleRelationship, such as
Shown in formula (6):
As it can be seen that the power output of crawling mode lower hub hydraulic motor depends primarily on variable pump swash plate aperture β, hydraulic circuit pressure
Power difference Δ P and engine speed ωe, wherein oil circuit pressure depends primarily on the load torque of front-wheel, when vehicle is in crawling mould
In the case that target vehicle speed of travel under formula determines, vehicle driving demand power and demand torque can accordingly really at this time
It is fixed, and then can determine the hydraulic circuit pressure differential Δ P of current demand, then the relationship according to shown in formula (6), by adjusting change
Measure the i.e. adjustable engine speed ω of discharge capacity (i.e. swash plate aperture β) of pumpeOperation interval；
Based on the crawling speed of operation v arbitrarily allowedcreep, the demand power P at front vehicle wheel is being determinedcreep, wheel hub is hydraulic
Motor rotary speed ωmAnd after closed circuit hydraulic pressure difference Δ P, it may further determine that the region of search of variable pump swash plate aperture
According to the optimized rotating speed section [ω of enginee,opt,min,ωe,opt,max], convolution (2) can determine corresponding under crawling mode
The minimum swash plate aperture β of the variable pump of current crawling speedcreep,minWith maximum swash plate aperture βcreep,max, as shown in formula (7):
And then it can determine the corresponding pump swash plate aperture region of search, [β under current crawling speedcreep,min,…,βcreep,n,…,
βcreep,max]；
Step 2: engine demand power determines, corresponding arbitrary pump swash plate aperture and current closed circuit hydraulic pressure difference,
In conjunction with the efficiency calculation formula of variable pump and wheel hub hydraulic motor, obtain when corresponding engine demand function under front pump swash plate aperture
Rate；
Using the efficiency calculation formula of variable pump and wheel hub hydraulic motor, it is calculated when the corresponding hydraulic change of front pump swash plate aperture
Measure the volumetric efficiency η of pumpcreep,pv,n, mechanical efficiency ηcreep,pm,nAnd the volumetric efficiency η of wheel hub hydraulic motorcreep,mv,n, machine
Tool efficiency etacreep,mm,n；And then it obtains when corresponding engine demand power P under front pump swash plate aperturee,req,n, as shown in formula (8):
Pe,req,n=Pcreep/ηcreep,pv,n/ηcreep,pm,n/ηcreep,mv,n/ηcreep,mm,n (8)
Step 3: engine working point determines, based on when front hub hydraulic motor rotary speed and pump swash plate opening information, solution is obtained
The corresponding engine speed of difference pump swash plate aperture, using the demand power in step 2, solution is obtained when front pump swash plate aperture
Corresponding engine speed torque operating point；
Step 4: setting target optimizing function, is based on overall efficiency principle of optimality, chooses and start when front pump swash plate aperture is corresponding
For engine oil consumption as objective optimization function, the smallest point of objective optimization function is the optimal point of system overall efficiency；
Based on the thought that overall efficiency is optimal, iterative search obtain under current crawling speed corresponding optimal pump swash plate aperture and
Optimal engine operating point is chosen and works as the corresponding engine consumption B of front pump swash plate aperturee,nAs objective function, such as formula (9) institute
Show, it is clear that the smallest point of objective function is the optimal point of system overall efficiency, i.e., optimal pumpage controls target and starts
Machine optimized rotating speed, direct torque target；
Fn(βcreep,n)=Be,n=be,nPe,req,n (9)
In formula, be,nIndicate corresponding fuel consumption rate under present engine operating point.
2. a kind of crawling mode pump displacement control optimal based on overall efficiency described in accordance with the claim 1, feature
It is, the step 5 iteration optimizing solution specifically includes the following contents:
The optimizing of golden cut algorithm iteration is utilized according to target optimizing function shown in formula (9), in the pump swash plate aperture region of search
The corresponding optimal pump swash plate aperture of the interior current crawling speed of rapid solving, it is specific as follows shown in:
1) the primary pump swash plate aperture region of search having had determined that, [a (1), b (1)]=[β are selectedcreep,min, 1], setting search
Required precision tol, golden section coefficient T=0.618, cycle counter initial value k=1；
2) c (k)=a (k)+(1-T) (b (k)-a (k)) is enabled, d (k)=b (k)-(1-T) (b (k)-a (k)) calculates Fc=F (c
(k)), Fd=F (d (k))；Wherein, F indicates target optimizing function；
3) if Fc < Fd, goes to step 4)；Otherwise step 5) is gone to；
4) a (k+1)=a (k), b (k+1)=d (k), d (k+1)=c (k), Fd=Fc are enabled；
It enables c (k+1)=a (k+1)+(1-T) (b (k+1)-a (k+1)), calculates Fc=F (c (k+1)), go to step 6)；
5) a (k+1)=c (k), c (k+1)=d (k), b (k+1)=b (k), Fc=Fd are enabled；
Enable d (k+1)=b (k+1)-(1-T) (b (k+1)-a (k+1))；It calculates Fd=F (d (k+1)), goes to step 6)；
6) k=k+1 is enabled；If meeting b (k)-a (k) >=tol, return step 3 at this time) continue to iterate to calculate, until iteration meter
Calculate result convergence；Otherwise it stops search.
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| JP2009127826A (en) * | 2007-11-27 | 2009-06-11 | Toyota Motor Corp | Controller of variable displacement pump/motor transmission |
| US20170081826A1 (en) * | 2014-03-03 | 2017-03-23 | Cnh Industrial America Llc | Compact Wheel Loader |
| CN107575316A (en) * | 2017-10-17 | 2018-01-12 | 杨青海 | A kind of closed loop control method for improving Fuel Economy |
| CN109808677A (en) * | 2019-03-27 | 2019-05-28 | 吉林大学 | A kind of wheel hub hydraulic hybrid power system pumpage Design of non-linear controllers method |
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2019
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009127826A (en) * | 2007-11-27 | 2009-06-11 | Toyota Motor Corp | Controller of variable displacement pump/motor transmission |
| US20170081826A1 (en) * | 2014-03-03 | 2017-03-23 | Cnh Industrial America Llc | Compact Wheel Loader |
| CN107575316A (en) * | 2017-10-17 | 2018-01-12 | 杨青海 | A kind of closed loop control method for improving Fuel Economy |
| CN109808677A (en) * | 2019-03-27 | 2019-05-28 | 吉林大学 | A kind of wheel hub hydraulic hybrid power system pumpage Design of non-linear controllers method |
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