CN111559377B - Speed regulation control method for double-flow transmission system of wheeled tractor - Google Patents

Speed regulation control method for double-flow transmission system of wheeled tractor Download PDF

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CN111559377B
CN111559377B CN202010442403.7A CN202010442403A CN111559377B CN 111559377 B CN111559377 B CN 111559377B CN 202010442403 A CN202010442403 A CN 202010442403A CN 111559377 B CN111559377 B CN 111559377B
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tractor
speed
delta
priority
resistance
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CN111559377A (en
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夏光
纵华宇
高军
于星海
张亮
王跃强
李嘉诚
夏岩
陈建杉
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Hefei University of Technology
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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
    • 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
    • B60W30/18172—Preventing, or responsive to skidding of wheels
    • 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
    • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
    • B60W40/10—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to vehicle motion
    • 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
    • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
    • B60W40/10—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to vehicle motion
    • B60W40/105—Speed
    • 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
    • B60W2300/00—Indexing codes relating to the type of vehicle
    • B60W2300/15—Agricultural vehicles
    • B60W2300/152—Tractors
    • 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
    • B60W2720/00—Output or target parameters relating to overall vehicle dynamics
    • B60W2720/10—Longitudinal speed

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  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Control Of Transmission Device (AREA)
  • Control Of Fluid Gearings (AREA)

Abstract

The invention discloses a speed regulation control method for a double-flow transmission system of a wheeled tractor, which is characterized in that when the operation resistance and the road adhesion condition of the tractor change, the speed regulation control is divided into two different priorities of passing priority and production efficiency priority by grading the slip ratio of a driving wheel of the tractor, and the slip ratio control and the vehicle speed control are respectively executed. The invention can determine the transmission mode of the double-flow transmission system by grading the current operation resistance of the tractor during the speed control, and carry out variable speed regulation according to the maximum production rate variable speed rule, thereby keeping the production efficiency of the tractor to the maximum extent.

Description

Speed regulation control method for double-flow transmission system of wheeled tractor
Technical Field
The invention relates to the field of vehicle speed change control research and design, in particular to a speed regulation control method for a double-flow transmission system of a wheeled tractor.
Background
Unlike the requirement of passenger cars for vehicle fuel economy, tractors are more concerned about the production efficiency of the units. In the operation process of the tractor, the slip rate of the driving wheels and the speed of the tractor can influence the production efficiency of the tractor. The existing speed regulation control for the tractor with the hydraulic mechanical double-flow transmission system only considers the speed regulation of the tractor and ignores the control of the slip rate of a driving wheel, and a corresponding speed regulation method is not established by taking the slip rate and the speed as a coupled whole, so that the slip rate of the driving wheel is easy to deteriorate and the phenomenon of the slip of the driving wheel occurs in the speed regulation process, so that the trafficability of the tractor is reduced, and finally the production efficiency of the tractor is reduced.
In addition, in the prior art, the influence of the transmission efficiency fluctuation of the hydraulic speed regulation branch on the transmission efficiency of the whole transmission system is not considered in the speed regulation control process of the hydraulic mechanical double-flow transmission system, and when the dynamic speed change rule of the tractor is determined, the maximum output power of the engine is usually equal to the maximum driving power of the driving wheels of the tractor, so that the actual speed regulation effect is greatly reduced.
Disclosure of Invention
The invention provides a speed regulation control method for a double-flow transmission system of a wheeled tractor to overcome the defects of the prior art, so that the speed regulation can be performed according to the highest-productivity speed regulation law when the road attachment condition or the tractor operation resistance changes, and the tractor still has higher production efficiency.
In order to achieve the purpose, the invention provides the following technical scheme:
the invention relates to a speed regulation control method for a double-flow transmission system of a wheeled tractor, which is characterized by comprising the following steps of:
step 1, obtaining the slip ratio delta of a tractor driving wheel by using a formula (1) so as to determine the priority of speed regulation control, wherein the priority of the speed regulation control comprises the following steps: passing priority and production efficiency priority;
Figure BDA0002504454010000011
in the formula (1), v represents the actual speed of the tractor acquired by a speed sensor; v' represents the theoretical speed of the tractor acquired by the rotating speed sensor;
step 2, carrying out corresponding control according to the priority of the speed regulation control, comprising the following steps:
when the priority is passing priority, carrying out slip rate control on the tractor;
and when the priority is the priority of production efficiency, controlling the speed of the tractor.
The speed regulation control method of the present invention is also characterized in that the priority of the speed regulation control in step 1 is determined according to the following method:
the slip rate delta of the driving wheel is compared with a lower threshold value deltaminAnd an upper threshold δmaxFor comparison, if the slip ratio of the tractor driving wheel is in the interval [ delta ]min,δmax]In the method, the speed regulation control of the tractor takes the production efficiency as the first priority; otherwise, the speed regulation control of the tractor takes the trafficability as the first priority.
The lower threshold value deltaminIs determined according to the following method:
step 1A.1, adjusting the road adhesion condition and the tractor operation resistance;
step 1A.2, measuring the maximum traction efficiency eta of the tractormax；
Step 1A.3, keeping the road adhesion condition unchanged and reducing the operation resistance of the tractor;
step 1A.4, measuring the slip rate of the driving wheel under each resistance state;
step 1A.5, measuring the traction efficiency of the tractor under each slip ratio;
step 1A.6, the traction efficiency of the tractor is lower than the maximum traction efficiency etamaxSlip ratio at ×. DELTA% as a threshold value [ delta ]minWherein the value range of delta is 70-80.
The upper threshold value deltamaxIs determined according to the following method:
step 1B.1, adjusting the road adhesion condition and the tractor operation resistance;
step 1B.2, measuring the maximum traction efficiency eta of the tractormax；
Step 1B.3, keeping the road adhesion condition unchanged and increasing the operation resistance of the tractor;
step 1B.4, measuring the slip rate of the driving wheel under each resistance state;
step 1B.5, measuring the traction efficiency of the tractor under each slip ratio;
step 1B.6, the traction efficiency of the tractor is lower than the maximum traction efficiency etamaxSlip ratio at ×. DELTA% as a threshold value [ delta ]maxWherein the value range of delta is 70-80.
The slip ratio control in the step 2 is performed according to the following method:
if the slip ratio delta of the tractor driving wheel is less than the lower threshold value deltaminWhen the tractor is used, the speed regulation control of the tractor is realized by deepening the working depth of the machine tool or increasing the width of the harvesting machine tool;
if the slip ratio of the tractor driving wheel is larger than the upper limit threshold value deltamaxIn time, the speed regulation control of the tractor is realized by reducing the working depth of the machine or the width of the harvester.
The speed control in the step 2 is to make the tractor perform speed change regulation according to the speed change rule of the highest productivity after determining the transmission mode of the tractor double-flow transmission system under the current resistance level according to the obtained actual speed v and acceleration a of the tractor and according to the following conditions:
when a is 0 and v is v2If the current resistance level is no resistance, the transmission mode is pure mechanical transmission MT;
when 0 is present<a≤a1And v is<v1When the current resistance level is small resistance, the transmission mode is pure mechanical transmission MT;
when a is1<a≤a2And v is<v1If the current resistance level is the medium resistance, the transmission mode is a hydraulic mechanical double-flow transmission HMT;
when a is>a2And v is<v1If the current resistance level is large resistance, the transmission mode is pure hydraulic transmission (HST);
wherein v is1And v2Respectively is the lower limit and the upper limit of the high-efficiency operation vehicle speed interval; a is1And a2Respectively, the lower and upper limits of acceleration.
Lower limit a of the acceleration1And an upper limit a2Is determined according to the following method:
step 2A.1, under the current operation type, keeping other operation conditions of the tractor unchanged, and adjusting the operation resistance of the tractor;
step 2A.2, only adjusting the diesel engine to determine the upper limit value of the resistance which can be overcome in the pure mechanical transmission MT mode;
step 2A.3, acquiring the acceleration of the tractor under the current resistance state and the initial accelerator opening degree and taking the acceleration as a lower limit a1；
Step 2A.4, adjusting the diesel engine and the displacement ratio to determine the upper limit value of the resistance which can be overcome in the hydraulic machinery double-flow transmission HMT mode;
step 2A.5, acquiring the acceleration of the tractor under the current resistance state and the initial accelerator opening degree and taking the acceleration as an upper limit a2。
The maximum production rate speed change rule is determined according to the following method:
step 2B.1, determining a current transmission mode;
step 2B.2, acquiring a vehicle speed v, an oil pressure P and an accelerator opening degree alpha;
step 2B.3, obtaining a three-dimensional data table obtained by the variation of the displacement ratio e of the double-flow transmission system of the wheeled tractor under the highest transmission efficiency along with the vehicle speed v and the oil pressure P under the conditions of sigma% and 100% of accelerator opening, wherein the value range of sigma is 90-95;
step 2B.4, acquiring the required throttle opening of the diesel engine according to the current transmission mode;
and 2B.5, inquiring the optimal displacement ratio corresponding to the vehicle speed v and the oil pressure P according to the three-dimensional data table.
The throttle opening degree of the diesel engine required in the step 2B.4 is determined according to the following method:
when the transmission mode is a hydraulic mechanical double-flow transmission HMT mode, the throttle opening of the diesel engine is adjusted to be sigma%, wherein the value range of sigma is 90-95;
when the transmission mode is a pure hydraulic transmission HST mode, the throttle opening of the diesel engine is adjusted to be 100%.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention considers the slip rate of the driving wheel of the tractor and the speed of the tractor as a coupled whole, introduces the slip rate control into an independent speed control strategy, and determines the priority of the speed control and the slip rate control by grading the slip rate, thereby establishing a proper speed regulation control method, not only effectively avoiding the slipping phenomenon of the driving wheel of the tractor, but also ensuring that the tractor has higher production efficiency.
2. When the speed of the tractor is controlled, the present operation resistance of the tractor is graded, the transmission mode of the tractor transmission system under the condition of adapting to the present resistance is determined, and the advantages of jumping and rapid switching of the transmission mode of the double-flow transmission system are fully utilized, so that the tractor has excellent speed regulation capability and higher transmission efficiency.
3. The invention can classify the speed regulation control into two different priorities of trafficability priority and production efficiency priority by classifying the slip ratio of the driving wheels of the tractor when the tractor changes in operation resistance and road adhesion conditions, and respectively execute the slip ratio control and the vehicle speed control. When the speed of the tractor is controlled, the current operation resistance of the tractor is graded, the transmission mode of the double-flow transmission system is determined, and the variable speed regulation is carried out according to the maximum productivity variable speed rule, so that the production efficiency of the tractor is maintained to the maximum extent.
Drawings
FIG. 1 is a flow chart of the speed control method of the present invention;
FIG. 2 is a graph illustrating the grading of slip ratio grading according to the present invention;
FIG. 3 is a front end block diagram of a dual flow transmission system of the present invention;
reference numbers in the figures: a Z1 power input shaft; c1 transfer gear; z2 split axis; p1 bidirectional variable displacement plunger pump; f1 adjustable throttle valve; an M1 bidirectional fixed displacement motor; z3 confluence axis; TY conflux planetary gear train sun gear; an XJ converging planetary gear train planet carrier; a CQ confluence planetary gear train gear ring; an L1 HMT clutch; l2 HST clutch.
Detailed Description
In the embodiment, the speed regulation control method for the double-flow transmission system of the wheeled tractor is characterized in that when the working resistance and the road adhesion condition of the tractor are changed, the speed regulation control is divided into two different priorities of passing priority and production efficiency priority by grading the slip rate of the driving wheels of the tractor, and the slip rate control and the vehicle speed control are respectively executed. When the speed of the tractor is controlled, the current operation resistance of the tractor is graded, the transmission mode of the double-flow transmission system is determined, and the variable speed regulation is carried out according to the maximum productivity variable speed rule, so that the production efficiency of the tractor is kept to the maximum extent. Specifically, as shown in fig. 1, the speed regulation control method is performed according to the following method:
step 1, obtaining the slip rate of a tractor driving wheel by using a formula (1) so as to determine the priority of speed regulation control, wherein the priority of the speed regulation control comprises the following steps: passing priority and production efficiency priority;
Figure BDA0002504454010000041
in the formula (1), v represents the actual speed of the tractor acquired by a speed sensor; v' represents the theoretical speed of the tractor acquired by the rotating speed sensor;
step 2, carrying out corresponding control according to the priority of the speed regulation control, comprising the following steps:
when the priority is passing priority, the slip rate of the tractor is controlled;
and when the priority is the priority of production efficiency, controlling the speed of the tractor.
Specifically, the slip ratio δ of the driving wheel is compared with the lower threshold δ in fig. 2minAnd an upper threshold δmaxAnd comparing to determine the priority of the speed regulation control. If the slip ratio of the tractor driving wheel is in the interval [ delta ]min,δmax]In the interior, the speed regulation control of the tractor is startedThe production efficiency is a first priority; otherwise, the speed regulation control of the tractor takes the trafficability as the first priority.
Wherein the lower threshold value deltaminThe determination is carried out according to the following method:
step 2A.1, adjusting the road adhesion condition and the tractor operation resistance;
step 2A.2, measuring the maximum traction efficiency eta of the tractormax；
Step 2A.3, keeping the road adhesion condition unchanged and reducing the operation resistance of the tractor;
step 2A.4, measuring the slip rate of the driving wheel under each resistance state;
step 2A.5, measuring the traction efficiency of the tractor under each slip ratio;
step 2A.6, the traction efficiency of the tractor is lower than the maximum traction efficiency etamaxSlip ratio at ×. DELTA% as a threshold value [ delta ]minWherein the value range of delta is 70-80. The value of delta only influences the time point of the intervention of the speed regulation control in the invention, but does not influence the control effect of the speed regulation control. For example, when Δ is 70, the timing at which the throttle control is engaged is later than the timing at which the system is engaged when Δ is 80. In practical engineering application, the value of delta can be determined after experimental analysis according to needs.
In a specific implementation, the upper threshold δmaxThe determination is carried out according to the following method:
step 2B.1, adjusting the road adhesion condition and the tractor operation resistance;
step 2B.2, measuring the maximum traction efficiency eta of the tractormax；
Step 2B.3, keeping the road adhesion condition unchanged and increasing the operation resistance of the tractor;
step 2B.4, measuring the slip rate of the driving wheel under each resistance state;
step 2B.5, measuring the traction efficiency of the tractor under each slip ratio;
step 2B.6, the traction efficiency of the tractor is lower than the maximum traction efficiency etamaxSlip ratio at ×. DELTA% as a threshold value [ delta ]maxWherein the value range of delta is 70-80.
Step 3, carrying out corresponding speed regulation control according to different control priorities, and when the speed regulation control is carried out by taking the passing property as the first priority, carrying out slip rate control and executing the step 3.1; when the speed regulation control takes the production efficiency as the first priority, the speed control is carried out, and the step 3.2 is executed;
step 3.1, slip ratio control is carried out according to the following method:
step 3.1.1, obtaining the slip ratio delta of the driving wheel of the tractor;
step 3.1.2, comparing the slip ratio delta of the driving wheel with the lower threshold delta in the figure 2minAnd an upper threshold δmaxComparing;
step 3.1.3, if the slip ratio of the driving wheels of the tractor is less than the lower limit threshold value deltaminThe speed regulation control of the tractor takes the increase of the operation resistance as a control target and is realized by a mode of deepening the operation tilling depth of the machine tool or increasing the width of the harvesting machine tool; if the slip ratio of the driving wheels of the tractor is larger than the upper limit threshold value deltamaxThe speed regulation control of the tractor takes the reduction of the operation resistance as a control target and is realized by reducing the operation tilling depth of the machine tool or reducing the width of the harvesting machine tool;
and 3.2, controlling the vehicle speed according to the following method:
step 3.2.1, acquiring the actual speed v of the tractor;
step 3.2.2, acquiring the acceleration a of the tractor;
step 3.2.3, determining the transmission mode of the tractor double-flow transmission system under the current resistance level according to the following conditions:
when a is 0 and v is v2When the resistance level is no resistance, the transmission mode is pure mechanical transmission MT;
when 0 is present<a≤a1And v is<v1When the current resistance level is small resistance, the transmission mode is pure mechanical transmission MT;
when a is1<a≤a2And v is<v1When the current resistance level is the medium resistance, the transmission mode is the hydraulic mechanical double-flow transmission HMT;
when a is>a2And v is<v1When the current resistance level is large resistance, the transmission mode is pure hydraulic transmission HST;
wherein v is1And v2Respectively is the lower limit and the upper limit of the high-efficiency operation vehicle speed interval; a is1And a2Respectively, the lower and upper limits of acceleration. The lower limit and the upper limit of the high-efficiency operation vehicle speed interval of different operation types are different, and the upper limit and the lower limit of the interval are generally determined by industry experience or a test calibration mode. For example, when the wheeled tractor is used for seeding, the high-efficiency operation speed range is 5-9 km/h.
In a specific embodiment, the lower limit a of the acceleration1And an upper limit a2Is determined according to the following method:
step a, under the current operation type, keeping other operation conditions of the tractor unchanged, and adjusting the operation resistance of the tractor;
b, only adjusting the diesel engine to determine the upper limit value of the resistance which can be overcome in the MT mode of the pure mechanical transmission;
step c, acquiring the acceleration of the tractor under the current resistance state and the initial accelerator opening degree and taking the acceleration as a lower limit a1；
D, adjusting the diesel engine and the displacement ratio to determine the upper limit value of the resistance which can be overcome in the hydraulic machinery double-flow transmission HMT mode;
step e, acquiring the acceleration of the tractor under the current resistance state and the initial accelerator opening degree and taking the acceleration as an upper limit a2。
And 3.2.4, changing speed according to the highest productivity speed change rule:
step 3.2.4.1, determining the current transmission mode;
step 3.2.4.2, acquiring a vehicle speed v, an oil pressure P and an accelerator opening degree alpha;
and 3.2.4.3, obtaining a three-dimensional data table obtained by the variation of the displacement ratio e of the double-flow transmission system of the wheeled tractor under the conditions of the maximum transmission efficiency of the accelerator opening of sigma% and the accelerator opening of 100% along with the change of the vehicle speed v and the oil pressure P, wherein the value range of sigma is 90-95. (ii) a
Step 3.2.4.4, acquiring the required throttle opening of the diesel engine according to the current transmission mode;
when the transmission mode is a hydraulic mechanical double-flow transmission HMT mode, the throttle opening of the diesel engine is adjusted to be 90%, wherein the value range of sigma is 90-95; the value of sigma determines the output power of the diesel engine, and in practical engineering application, the specific value of sigma is determined by a test calibration mode.
When the transmission mode is a pure hydraulic transmission HST mode, the throttle opening of the diesel engine is adjusted to be 100%.
Step 3.2.4.5, inquiring the optimal displacement ratio corresponding to the vehicle speed v and the oil pressure P according to the three-dimensional data table;
and 3.2.4.6, correspondingly adjusting the opening of the diesel engine valve and the displacement of the hydraulic pump according to the steps 3.2.4.4 and 3.2.4.5.
Examples
FIG. 3 is a schematic diagram of a dual flow transmission front end module, and the transition to dual flow transmission modes may be accomplished by adjusting the displacement of the HMT clutch L1, the HST clutch L2, and the hydraulic pump in the front end module. Such as: the HMT clutch L1 is combined, the HST clutch L2 is separated, the displacement of the hydraulic pump is adjusted to be 0, and the double-flow transmission system is in a pure mechanical transmission state; and when the HMT clutch L1 is combined and the HST clutch L2 is disengaged, the displacement of the hydraulic pump is not 0, and the double-flow transmission system is in a hydraulic and mechanical double-flow transmission state.
Assuming that a wheeled tractor equipped with the dual-flow transmission system is harvesting in a pure mechanical transmission mode, suddenly, the working resistance of the tractor increases sharply, and if the speed regulating system detects that the slip ratio of the driving wheels is greater than the upper threshold value delta at the momentmaxIn order to ensure the passing performance of the tractor, the speed regulating system can send a slip rate control signal, and at the moment, the tractor can send a signal for reminding a driver to reduce the operation width of the machine tool; if the speed regulating system detects that the slip ratio of the driving wheel is in the interval [ delta ] at the momentmin,δmax]In order to ensure the production efficiency of the tractor, the speed regulating system can send a speed control signal. The speed regulating system judges the current working resistance according to the detected tractor speed and acceleration signals and sends out switching transmissionA signal of a pattern. If the vehicle speed is lower than the lower limit value and the acceleration is at a1<a≤a2And when the speed is higher than the set speed, switching to a hydraulic mechanical double-flow transmission mode. When the hydraulic engine is in a hydraulic mechanical double-flow transmission mode, on one hand, the speed regulating system determines the opening degree of the throttle of the diesel engine required by the current resistance state according to the transmission mode; on the other hand, the speed regulating system queries the three-dimensional data form according to the current vehicle speed v and the oil pressure P to obtain the displacement ratio corresponding to the highest transmission efficiency. Finally, the speed of the tractor can be adjusted by adjusting the opening of the throttle valve and the discharge capacity of the hydraulic pump, and the tractor still has high production efficiency after the operation resistance fluctuates.

Claims (7)

1. A speed regulation control method for a double-flow transmission system of a wheeled tractor is characterized by comprising the following steps: the method comprises the following steps:
step 1, obtaining the slip ratio delta of a tractor driving wheel by using a formula (1) so as to determine the priority of speed regulation control, wherein the priority of the speed regulation control comprises the following steps: passing priority and production efficiency priority;
Figure FDA0002946285800000011
in the formula (1), v represents the actual speed of the tractor acquired by a speed sensor; v' represents the theoretical speed of the tractor acquired by the rotating speed sensor;
the priority of the speed regulation control in the step 1 is determined according to the following method:
the slip rate delta of the driving wheel is compared with a lower threshold value deltaminAnd an upper threshold δmaxFor comparison, if the slip ratio of the tractor driving wheel is in the interval [ delta ]min,δmax]In the method, the speed regulation control of the tractor takes the production efficiency as the first priority; otherwise, the speed regulation control of the tractor takes the passing ability as the first priority;
the lower threshold value deltaminIs determined according to the following method:
step 1A.1, adjusting the road adhesion condition and the tractor operation resistance;
step 1A.2, measuring the maximum traction efficiency eta of the tractormax；
Step 1A.3, keeping the road adhesion condition unchanged and reducing the operation resistance of the tractor;
step 1A.4, measuring the slip rate of the driving wheel under each resistance state;
step 1A.5, measuring the traction efficiency of the tractor under each slip ratio;
step 1A.6, the traction efficiency of the tractor is lower than the maximum traction efficiency etamaxSlip ratio at ×. DELTA% as a threshold value [ delta ]minWherein the value range of delta is 70-80;
step 2, carrying out corresponding control according to the priority of the speed regulation control, comprising the following steps:
when the priority is passing priority, carrying out slip rate control on the tractor;
and when the priority is the priority of production efficiency, controlling the speed of the tractor.
2. The speed governing control method of claim 1, wherein the upper threshold δmaxIs determined according to the following method:
step 1B.1, adjusting the road adhesion condition and the tractor operation resistance;
step 1B.2, measuring the maximum traction efficiency eta of the tractormax；
Step 1B.3, keeping the road adhesion condition unchanged and increasing the operation resistance of the tractor;
step 1B.4, measuring the slip rate of the driving wheel under each resistance state;
step 1B.5, measuring the traction efficiency of the tractor under each slip ratio;
step 1B.6, the traction efficiency of the tractor is lower than the maximum traction efficiency etamaxSlip ratio at ×. DELTA% as a threshold value [ delta ]maxWherein the value range of delta is 70-80.
3. The speed control method according to claim 1, wherein the slip ratio control in step 2 is performed according to the following method:
if the slip ratio delta of the tractor driving wheel is less than the lower threshold value deltaminWhen the tractor is used, the speed regulation control of the tractor is realized by deepening the working depth of the machine tool or increasing the width of the harvesting machine tool;
if the slip ratio of the tractor driving wheel is larger than the upper limit threshold value deltamaxIn time, the speed regulation control of the tractor is realized by reducing the working depth of the machine or the width of the harvester.
4. The speed regulation control method according to claim 1, wherein the speed control in step 2 is to make the tractor perform speed regulation according to the speed regulation law of the highest productivity after determining the transmission mode of the tractor dual-flow transmission system at the current resistance level according to the acquired actual speed v and acceleration a of the tractor and as follows:
when a is 0 and v is v2If the current resistance level is no resistance, the transmission mode is pure mechanical transmission MT;
when 0 is present<a≤a1And v is<v1When the current resistance level is small resistance, the transmission mode is pure mechanical transmission MT;
when a is1<a≤a2And v is<v1If the current resistance level is the medium resistance, the transmission mode is a hydraulic mechanical double-flow transmission HMT;
when a is>a2And v is<v1If the current resistance level is large resistance, the transmission mode is pure hydraulic transmission (HST);
wherein v is1And v2Respectively is the lower limit and the upper limit of the high-efficiency operation vehicle speed interval; a is1And a2Respectively, the lower and upper limits of acceleration.
5. The speed-regulation control method according to claim 4, wherein the lower limit a of the acceleration1And an upper limit a2Is according to the followingThe method comprises the following steps:
step 2A.1, under the current operation type, keeping other operation conditions of the tractor unchanged, and adjusting the operation resistance of the tractor;
step 2A.2, only adjusting the diesel engine to determine the upper limit value of the resistance which can be overcome in the pure mechanical transmission MT mode;
step 2A.3, acquiring the acceleration of the tractor under the current resistance state and the initial accelerator opening degree and taking the acceleration as a lower limit a1；
Step 2A.4, adjusting the diesel engine and the displacement ratio to determine the upper limit value of the resistance which can be overcome in the hydraulic machinery double-flow transmission HMT mode;
step 2A.5, acquiring the acceleration of the tractor under the current resistance state and the initial accelerator opening degree and taking the acceleration as an upper limit a2。
6. The throttle control method according to claim 4, wherein the highest productivity shift schedule is determined according to the following method:
step 2B.1, determining a current transmission mode;
step 2B.2, acquiring a vehicle speed v, an oil pressure P and an accelerator opening degree alpha;
step 2B.3, obtaining a three-dimensional data table obtained by the variation of the displacement ratio e of the double-flow transmission system of the wheeled tractor under the highest transmission efficiency along with the vehicle speed v and the oil pressure P under the conditions of sigma% and 100% of accelerator opening, wherein the value range of sigma is 90-95;
step 2B.4, acquiring the required throttle opening of the diesel engine according to the current transmission mode;
and 2B.5, inquiring the optimal displacement ratio corresponding to the vehicle speed v and the oil pressure P according to the three-dimensional data table.
7. The speed governing control method according to claim 6, wherein the throttle opening of the diesel engine required in step 2B.4 is determined according to the following method:
when the transmission mode is a hydraulic mechanical double-flow transmission HMT mode, the throttle opening of the diesel engine is adjusted to be sigma%, wherein the value range of sigma is 90-95;
when the transmission mode is a pure hydraulic transmission HST mode, the throttle opening of the diesel engine is adjusted to be 100%.
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