CN111306278A - Hydraulic mechanical continuously variable transmission of commercial vehicle and starting control method - Google Patents
Hydraulic mechanical continuously variable transmission of commercial vehicle and starting control method Download PDFInfo
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- CN111306278A CN111306278A CN202010278182.4A CN202010278182A CN111306278A CN 111306278 A CN111306278 A CN 111306278A CN 202010278182 A CN202010278182 A CN 202010278182A CN 111306278 A CN111306278 A CN 111306278A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H47/00—Combinations of mechanical gearing with fluid clutches or fluid gearing
- F16H47/02—Combinations of mechanical gearing with fluid clutches or fluid gearing the fluid gearing being of the volumetric type
- F16H47/04—Combinations of mechanical gearing with fluid clutches or fluid gearing the fluid gearing being of the volumetric type the mechanical gearing being of the type with members having orbital motion
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H2061/0075—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by a particular control method
- F16H2061/0081—Fuzzy logic
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H2061/0075—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by a particular control method
- F16H2061/009—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by a particular control method using formulas or mathematic relations for calculating parameters
Abstract
The invention designs and develops a hydraulic mechanical stepless speed changer of a commercial vehicle, comprising a mechanical input shaft; the first gear is sleeved on the mechanical input shaft and can rotate along with the mechanical input shaft; and is freely rotatable about the mechanical input shaft; a hydraulic drive shaft disposed parallel to the mechanical input shaft; the second gear is sleeved on the hydraulic transmission shaft, is meshed with the first gear and can drive the hydraulic transmission shaft to rotate; the input end of the hydraulic speed regulating mechanism is connected with the hydraulic transmission shaft; the rotating power provided by the engine can drive the mechanical input shaft to rotate and drive the hydraulic transmission shaft to input the rotating power through the engine, one part of the rotating power is transmitted to the mechanical transmission mechanism through the shunting mechanism, the other part of the rotating power is transmitted to the hydraulic speed regulating mechanism, and the rotating power is finally output after being synthesized through the confluence mechanism.
Description
Technical Field
The invention relates to the field of hydraulic mechanical continuously variable transmissions, in particular to a hydraulic mechanical continuously variable transmission of a commercial vehicle and a starting control method.
Background
In the face of increasingly tense energy and environmental protection pressure, governments of various countries have come out a great number of policy measures in sequence, and the improvement of the energy utilization efficiency of vehicles is encouraged. At present, the market trend is mainly the pure electric vehicle, but before the key technologies such as the battery and the like do not make great breakthrough, the factors such as the endurance mileage, the battery life and the cost of the pure electric vehicle still severely limit the development of the pure electric vehicle, and the breakthrough of the technologies is not a very good thing. The development of electric automobiles is puzzled for a long time by the problems of improving the energy density of the storage battery, prolonging the service life, reducing the use cost and the like. The fuel powered vehicle will still dominate the market for a considerable period of time.
Commercial vehicles are used extremely widely as the primary force of road transport. Therefore, if the fuel utilization efficiency of the commercial vehicle can be improved, the energy and environmental protection pressure can be greatly reduced. The transmission system is an important component of a vehicle, and how to improve transmission efficiency is a problem worthy of long-term research. The transmission is the most critical ring in the transmission system, and the improvement of the transmission can greatly improve the transmission efficiency. At present, the domestic commercial vehicle speed changer mainly adopts a manual gear as a main part, and a small number of AMT (automated mechanical transmission) vehicles are provided. The invention provides a novel HMCVT (hydro-mechanical continuously variable transmission) suitable for a commercial vehicle, which is used for improving the working condition adaptability and the fuel utilization rate of the commercial vehicle. The HMCVT is applied to the tractor on a large scale at first, can easily realize stepless speed change, and has extremely strong adaptability to complex terrains. But the use of HMCVTs on commercial vehicles is quite rare, probably due to the inherent impression of inefficient fluid transmission. However, the commercial vehicle also faces complex working conditions, the split transmission of the HMCVT just gives consideration to the transmission efficiency and the stepless speed change, and the HMCVT is very suitable for being applied to the commercial vehicle on a large scale. Compared with agricultural vehicles, commercial vehicles do not need larger torque, and the driving road conditions are much simpler than those of agricultural vehicles, so that simplification and improvement are needed on the basis of the HMCVT for the tractor, the HMCVT is suitable for the characteristic working condition characteristics of the commercial vehicles, and fuel saving is facilitated.
Disclosure of Invention
The invention designs and develops a hydraulic mechanical stepless speed changer of a commercial vehicle, wherein power is input by an engine, passes through a shunt mechanism, one part of the power is transmitted to a mechanical transmission mechanism, the other part of the power is transmitted to a hydraulic speed regulating mechanism, and finally is synthesized by a confluence mechanism and then output.
The invention also provides a control method of the hydraulic mechanical continuously variable transmission of the commercial vehicle, which can improve the starting smoothness, shorten the starting response time and better meet the starting intention of a driver.
The technical scheme provided by the invention is as follows:
a commercial vehicle hydro-mechanical continuously variable transmission comprising:
a mechanical input shaft;
the first gear is fixedly sleeved on the mechanical input shaft and can rotate along with the mechanical input shaft;
the mechanical transmission mechanism is sleeved on the mechanical input shaft in an empty mode and can freely rotate around the mechanical input shaft;
a hydraulic drive shaft disposed parallel to the mechanical input shaft;
the second gear is fixedly sleeved on the hydraulic transmission shaft, is meshed with the first gear and can drive the hydraulic transmission shaft to rotate;
the input end of the hydraulic speed regulating mechanism is connected with the hydraulic transmission shaft;
the mechanical input shaft can be driven to rotate by the rotary power provided by the engine, and the hydraulic transmission shaft is driven to rotate;
a planetary gear mechanism capable of converging the rotational power of the mechanical transmission mechanism and the hydraulic speed regulation mechanism and outputting the rotational power through an output end of the planetary gear mechanism;
a first clutch mechanism provided between the mechanical input shaft and the planetary gear mechanism, and capable of selectively coupling or decoupling the mechanical input shaft and the planetary gear mechanism;
a second clutch mechanism provided between the mechanical input shaft and the planetary gear mechanism output end, capable of selectively coupling or decoupling the mechanical input shaft and the planetary gear mechanism output end;
the third clutch mechanism is arranged between the hydraulic transmission shaft and the hydraulic speed regulating mechanism and can enable the hydraulic transmission shaft and the hydraulic speed regulating mechanism to be selectively combined or separated;
a reversing shaft;
a fourth clutch mechanism which is arranged between the output end of the hydraulic speed regulating mechanism and the reversing shaft and can selectively combine or separate the reversing shaft and the third clutch mechanism;
a power take-off shaft;
and a fifth clutch mechanism provided between the mechanical transmission mechanism and the power output shaft, and capable of selectively coupling or decoupling the power output shaft and the mechanical transmission mechanism.
Preferably, the planetary gear mechanism includes:
a first ring gear;
the first sun gear is connected with an output shaft of the hydraulic speed regulating mechanism;
a plurality of first planet gears distributed on the outer side of the first sun gear in a circumferential array and respectively meshed with the first sun gear and the first gear ring;
the first planet gear is rotatably supported on the first planet carrier, and the first planet carrier can receive the rotating power of the mechanical driving shaft and drive the first planet gear to rotate around the first sun gear so as to drive the first gear ring to rotate;
a second carrier integrally connected to the first ring gear;
a second ring gear;
the second sun gear is connected with an output shaft of the hydraulic speed regulating mechanism;
a plurality of second planet gears rotatably supported on the second planet carrier, distributed in a circumferential array outside the second sun gear, and respectively meshed with the second sun gear and the second ring gear;
a planetary gear output shaft connected with the second carrier.
Preferably, the mechanical transmission mechanism includes:
at least one idler gear, which is freely rotatable around the mechanical input shaft, and is freely sleeved on the mechanical input shaft;
at least one hollow gear, which is freely sleeved on the mechanical input shaft and can freely rotate around the mechanical input shaft;
at least one planet carrier meshing gear which is fixedly sleeved on the first planet carrier and is meshed with the empty gear;
and the connecting gear is fixedly sleeved on the second gear ring and is meshed with the hollow gear.
Preferably, the hydraulic governor mechanism includes:
the variable hydraulic pump is connected with the hydraulic transmission shaft;
a hydraulic motor in communication with the variable displacement hydraulic pump, the variable displacement hydraulic pump being capable of driving the hydraulic motor to rotate.
Preferably, the first clutch mechanism, the second clutch mechanism, the third clutch mechanism, and the fourth clutch mechanism are all engagement clutches.
Preferably, the method further comprises the following steps: and the combined output mechanism is arranged between the reverse shaft and the power output shaft.
A starting control method of a hydraulic mechanical continuously variable transmission of a commercial vehicle comprises the following steps:
inputting the releasing angle and the releasing speed of the brake pedal into a fuzzy controller, and obtaining an ideal transmission ratio combining the intention of a driver after analysis;
calculating the error of the ideal transmission ratio and the actual transmission ratio, and determining a switching function of the slip control according to the error;
and obtaining a transmission ratio regulation calculation formula according to the switching function of the sliding control, thereby realizing the real-time regulation of the transmission ratio of the mechanical stepless speed changer.
Preferably, the fuzzy sets of the angle of brake pedal release, the speed of brake pedal release and the ideal gear ratio are { VS, S, M, B, VB }, VS means small, S means small, M means medium, B means large, VB means large, the angle of brake pedal release is divided into 5 fuzzy domains, respectively [0,12], [12,24], [24,36], [36,48], [48,60], the speed of brake pedal release is divided into 5 fuzzy domains, respectively [0,15], [15,30], [30,45], [45,60], [60,75], and the ideal gear ratio is divided into 5 fuzzy domains, respectively [7.051,10], [10,14], [14,18], [18,22], [22,26.274 ].
Preferably, the switching function of the slip control is:
where s is the switching function of the slip control, e is the difference between the ideal transmission ratio and the actual transmission ratio, e ═ epsilon-epsilon*With ε being the ideal transmission ratio ε*C is the coefficient for the actual gear ratio.
Preferably, the transmission ratio regulation calculation formula is as follows:
wherein u is the displacement ratio, and f is-0.00008136 x1-0.001416·x2；x1For speed ratio, x2Is the derivative of the speed ratio, η is the mechanical efficiency.
The invention has the advantages of
The invention designs and develops a hydraulic mechanical stepless speed changer of a commercial vehicle, wherein power is input by an engine, passes through a shunt mechanism, one part of the power is transmitted to a mechanical transmission mechanism, the other part of the power is transmitted to a hydraulic speed regulating mechanism, and finally is synthesized by a confluence mechanism and then output.
The invention provides a new HMCVT structural form which accords with the running condition characteristics of commercial vehicles, and develops a sliding mode variable structure starting control strategy based on the upper bound on the basis.
The invention is based on the traditional tractor speed changer, and is greatly improved, so that the commercial vehicle HMCVT can be freely switched among 3 modes of pure hydraulic drive, pure mechanical drive and hydraulic mechanical drive. Compared with the traditional AMT and manual gear mode, the automatic transmission can better adapt to various driving conditions and improve the fuel economy.
Compared with the traditional AMT and manual gear modes, the sliding mode variable structure starting control strategy based on the upper bound is developed, the starting smoothness can be improved, the starting response time is shortened, the starting intention of a driver is more met, and the starting performance of the commercial vehicle is fundamentally improved.
The invention verifies that the improved HMCVT is suitable for commercial vehicles, can greatly improve the transmission efficiency, and can be popularized in a large scale, thereby greatly reducing the pressure of energy and environmental protection.
Drawings
Fig. 1 is a schematic structural diagram of a hydro-mechanical continuously variable transmission for a commercial vehicle according to the present invention.
FIG. 2 is a table of membership functions for the fuzzy controller according to the present invention.
FIG. 3 is a fuzzy inference output surface diagram according to the present invention.
Fig. 4 is a control frame diagram of the sliding mode variable structure of the invention.
Detailed Description
The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.
As shown in fig. 1, the present invention provides a hydromechanical continuously variable transmission for a commercial vehicle, comprising: the device comprises a flow dividing mechanism, a flow converging mechanism, a mechanical transmission mechanism and a hydraulic speed regulating mechanism.
The shunting mechanism shunts the rotating power of the engine to the mechanical input shaft 23 and the hydraulic transmission shaft 25, the mechanical input shaft 23 and the hydraulic transmission shaft 25 are arranged in parallel, and the first gear 1 is sleeved on the mechanical input shaft 23 and can rotate along with the mechanical input shaft 23; the second gear 2 is sleeved on the hydraulic transmission shaft 25, is meshed with the first gear 1 and can drive the hydraulic transmission shaft 25 to rotate; wherein, the rotation power provided by the engine can drive the mechanical input shaft 23 to rotate and drive the hydraulic transmission shaft 25 to rotate; the engine rotary power is divided.
The mechanical transmission mechanism is sleeved on the mechanical input shaft 23 in an empty mode and can freely rotate around the mechanical input shaft 23; the input end of the hydraulic speed regulating mechanism is connected with a hydraulic transmission shaft 25.
The planetary gear mechanism can converge the rotating power of the mechanical transmission mechanism and the hydraulic speed regulation mechanism and output the power through the output end of the planetary gear mechanism;
the first clutch mechanism is provided between the mechanical input shaft 23 and the planetary gear mechanism, and is capable of coupling or decoupling the mechanical input shaft 23 and the planetary gear mechanism;
the second clutch mechanism is arranged between the mechanical input shaft 23 and the output end of the planetary gear mechanism, and can enable the mechanical input shaft 23 to be combined with or separated from the output end of the planetary gear mechanism;
the third clutch mechanism is arranged between the hydraulic transmission shaft 25 and the hydraulic speed regulating mechanism, and can combine or separate the hydraulic transmission shaft and the hydraulic speed regulating mechanism;
the fourth clutch mechanism is arranged between the output end of the hydraulic speed regulating mechanism and the reversing shaft 28, and can enable the reversing shaft and the third clutch mechanism to be combined or separated;
and a fifth clutch mechanism provided between the mechanical transmission mechanism and the power take-off shaft 24 and capable of coupling or decoupling the power take-off shaft 24 to or from the mechanical transmission mechanism.
In another embodiment, the planetary gear mechanism is a double planetary gear structure: a first ring gear 20; the first sun gear 16 is connected with an output shaft 26 of the hydraulic speed regulating mechanism; a plurality of first planet gears 18 distributed in a circumferential array outside the first sun gear 16 and meshing with the first sun gear 16 and the first ring gear 20, respectively; the first planet carrier 21 is connected with the first planet gears 18, the first planet gears 18 are rotatably supported on the first planet carrier 21, and the first planet carrier 21 can drive the first planet gears 18 to rotate around the first sun gear 16 so as to drive the first ring gear 20 to rotate;
a second planet carrier integrally connected with the first ring gear; the second ring gear 22 and the second sun gear 17 are connected with an output shaft 26 of the hydraulic speed regulating mechanism; a plurality of second planet gears 19 are rotatably supported on the second planet carrier, distributed on the outer side of the second sun gear 17 in a circumferential array and meshed with the second sun gear 17 and the second ring gear 22 respectively; the planetary gear output shaft 27 is connected to the second carrier 20.
In another embodiment, the mechanical transmission mechanism comprises: at least one idler gear, which is freely sleeved on the mechanical input shaft 23 and can freely rotate around the mechanical input shaft 23; the hollow gear is sleeved on the mechanical input shaft in an empty mode and can freely rotate around the mechanical input shaft; at least one planet carrier meshing gear which is fixedly sleeved on the first planet carrier 21 and is meshed with the empty gear; and at least one connecting gear fixedly sleeved on the second gear ring 22 and meshed with the hollow gear.
Preferably, the idler gears are two first idler gears 3 and two second idler gears 5, the hollow gears are two hollow gears 7 and two hollow gears 9, the planet carrier meshing gears are two planet carrier meshing gears 4 and two planet carrier meshing gears 6, and the connecting gears are two connecting gears 8 and two connecting gears 10.
In another embodiment, a hydraulic governor mechanism includes: a variable displacement hydraulic pump 29 connected to the hydraulic transmission shaft 25; the hydraulic motor 30 is connected to the variable displacement hydraulic pump 29, and the variable displacement hydraulic pump 29 can rotationally drive the hydraulic motor 30.
In the preferred embodiment, the first clutch mechanism is two on-coming clutches, clutch C1 and clutch C2, respectively, disposed within first idler gear 3 and second idler gear 5, respectively, the second clutch mechanism is two on-coming clutches, clutch C3 and clutch C4, respectively, and disposed within first idler gear 7 and second idler gear 9, respectively, the third clutch mechanism is clutch C8, and the fourth clutch mechanism is an on-coming clutch, labeled clutch C9, and the fifth clutch mechanism is an on-coming clutch, labeled clutch C5.
In another embodiment, the joint output mechanism is disposed between the reverse shaft 28 and the power take-off shaft 24.
The joint output mechanism includes:
the first reduction gear 12 is sleeved on an output shaft 27 of the planetary gear mechanism;
the first reduction idler gear 11 is idler-mounted on the power output shaft 24 and meshed with the first reduction gear 11; the second reduction gear 15 is sleeved on the output shaft 27 of the planetary gear mechanism; the second speed reduction idler gear 13 is idler sleeved on the power output shaft 24;
wherein the second reduction gear 15 and the second reduction idler gear 13 are located on both sides of the reverse shaft 28 and both mesh with the reverse shaft 28.
In another embodiment, the first and second reduction idler gears 11 and 13 each have a clutch therein, labeled clutch C6 and clutch C7, respectively, selectively engageable with the power take-off shaft 24.
The basic principle is that power is input by an engine, one part of the power is transmitted to a mechanical transmission mechanism through a flow dividing mechanism, the other part of the power is transmitted to a hydraulic speed regulating mechanism, and finally the power is synthesized by a converging mechanism and then output. The novel hydraulic transmission mechanism has the characteristics of simple structure, stable mechanical transmission efficiency, compact structure, flexible control and good fuel economy under complex driving road conditions.
The intelligent road condition switching system is characterized in that the transmission requirements of good road conditions and bad road conditions are fully considered, and intelligent switching can be performed among different modes. When starting and backing, the HMCVT adopts pure hydraulic drive, and exerts the characteristics of soft connection, low speed and large torque of the hydraulic drive. When starting, C6, C8 and C9 are engaged. C5 is not engaged, cutting off the energy flow of the direct mechanical transmission. C1, C2, C3 and C4 are not engaged, and the energy flow of the combined drive of the hydraulic machine is cut off. Meanwhile, the engagement of the C8 and the C9 communicates the energy flow of hydraulic transmission, and pure hydraulic transmission is realized. And when backing, C7, C8, C9 are engaged. Wherein the engagement of C7 causes the reverse gear on the shaft 6 (reverse shaft) to function, and the engagement and disengagement principles of the other clutches are the same as those at the time of starting; when the road condition is good, the pure mechanical transmission is adopted, the advantage of high mechanical transmission efficiency is exerted, and the defect of low hydraulic transmission efficiency is avoided. At this point C8 separates, cutting off the energy flow of the hydraulic section. And the specific engaging and disengaging conditions of each clutch in each gear are shown in table 1. Particularly, the gear 5 is a direct gear when the road condition is excellent, and only the C5 is engaged to realize direct gear transmission; when the road conditions are severe, the hydraulic machinery is adopted for combined driving, so that the transmission efficiency is high, stepless speed change can be realized, and the road surface type stepless speed change device is favorable for adapting to various complex terrains. At this point, C8 is engaged, connecting the hydraulic section energy flow. Because the range of the transmission ratio of the hydraulic speed regulating mechanism for realizing stepless speed change is limited, the gear shifting is realized through the change of gears meshed by different gears, and the engaging and disengaging conditions of each clutch are shown in table 1.
The matching of the clutch engagement and disengagement in the various modes is shown in table 1:
TABLE 1 Clutch MATCHING TABLE
"o" represents clutch engaged and "represents clutch disengaged.
From the above table, according to the different energy flow patterns, the working section can be divided into a pure hydraulic section, a hydraulic mechanical section and a pure mechanical section, and the hydraulic mechanical section and the pure mechanical section can be divided into a plurality of gears according to the different transmission ratios of the mechanical parts. The transmission efficiency is improved through the mechanical transmission mechanism, the expansion of the transmission ratio range is realized through the matching of the separation and the connection of the clutch, and the stepless speed change is realized through the regulation and control of the combination of the variable displacement hydraulic pump and the quantitative hydraulic motor. Compared with commercial vehicles using AMT or manual gears, the hybrid transmission device is better suitable for various driving conditions and can realize better fuel economy.
The clutch closure is matched as shown in table 1 above. The gear fit is as follows:
hydraulic mode starting: the energy flow is input from the input shaft, transmitted to the variable hydraulic pump 29 through the meshed gear 1 and the gear 2, the variable hydraulic pump 29 drives the fixed-quantity hydraulic motor 30, passes through the two planetary row driving shafts 27, passes through the meshed gear 12 and the gear 11, and is output by the output shaft.
Hydraulic mode backing: the energy flow is input from the input shaft, transmitted to the variable hydraulic pump 29 through the meshed gear 1 and the gear 2, the variable hydraulic pump 29 drives the fixed-quantity hydraulic motor 30, passes through the two planetary row driving shafts 27, passes through the meshed gear 15, the gear 14 and the gear 13, and is output by the output shaft.
Hydromechanical mode 1-gear combination: the energy flow is divided into two paths after being input from the input shaft, one path is mechanical transmission, and is transmitted to the double-stage planet row through the meshed gear 7 and the meshed gear 8; one path is hydraulic pressure transmission, and is transmitted to the variable displacement hydraulic pump 29 via the meshed gear 1 and gear 2, and the variable displacement hydraulic pump 29 drives the fixed displacement hydraulic motor 30 and transmits the same to the two-stage planetary line. Finally, the two-stage planetary lines converge, pass through the shaft 27, pass through the meshed gear 12 and the gear 11, and are output by the output shaft.
Hydromechanical mode 2-gear combination: the energy flow is divided into two paths after being input from the input shaft, one path is mechanical transmission, and is transmitted to the double-stage planet row through the meshed gear 9 and the meshed gear 10; one path is hydraulic pressure transmission, and is transmitted to the variable displacement hydraulic pump 29 via the meshed gear 1 and gear 2, and the variable displacement hydraulic pump 29 drives the fixed displacement hydraulic motor 30 and transmits the same to the two-stage planetary line. Finally, the two-stage planetary lines converge, pass through the shaft 27, pass through the meshed gear 12 and the gear 11, and are output by the output shaft.
Hydromechanical mode 3-gear combination: the energy flow is divided into two paths after being input from the input shaft, one path is mechanical transmission, and is transmitted to the double-stage planet row through the meshed gear 3 and the meshed gear 4; one path is hydraulic pressure transmission, and is transmitted to the variable displacement hydraulic pump 29 via the meshed gear 1 and gear 2, and the variable displacement hydraulic pump 29 drives the fixed displacement hydraulic motor 30 and transmits the same to the two-stage planetary line. Finally, the two-stage planetary lines converge, pass through the shaft 27, pass through the meshed gear 12 and the gear 11, and are output by the output shaft.
Hydromechanical mode 4-gear combination: the energy flow is divided into two paths after being input from the input shaft, one path is mechanical transmission, and is transmitted to the double-stage planet row through the meshed gear 5 and the meshed gear 6; one path is hydraulic pressure transmission, and is transmitted to the variable displacement hydraulic pump 29 via the meshed gear 1 and gear 2, and the variable displacement hydraulic pump 29 drives the fixed displacement hydraulic motor 30 and transmits the same to the two-stage planetary line. Finally, the two-stage planetary lines converge, pass through the shaft 27, pass through the meshed gear 12 and the gear 11, and are output by the output shaft.
Mechanical mode 2: the energy flow is input from the input shaft, transmitted to the second of the two planetary rows via the meshed gears 9 and 10, drives the shaft 27, and is output from the output shaft via the meshed gears 12 and 11.
Mechanical mode 3: the energy flow is input from the input shaft, transmitted to the second of the two-stage planetary rows via the meshed gears 3 and 4, drives the shaft 27, and is output from the output shaft via the meshed gears 12 and 11.
Mechanical mode 4: the energy flow is input from the input shaft, transmitted to the second of the two planetary rows via the meshed gears 5 and 6, drives the shaft 27, and is output from the output shaft via the meshed gears 12 and 11.
Mechanical mode 5: this is a direct gear, with energy flow input from the input shaft and output directly from the output shaft.
A control method of a hydraulic mechanical continuously variable transmission of a commercial vehicle is a sliding mode variable structure starting control method based on the upper bound.
The starting control of the commercial vehicle with the HMCVT is different from that of a common manual-gear commercial vehicle, the whole starting process is only completed by controlling a brake pedal by a driver, various traffic situations such as low-speed vehicle following, starting and warehousing and the like need to be dealt with, and the starting smoothness and the sensitivity when sudden braking is carried out in an emergency situation are guaranteed in the process.
When starting, a driver firstly steps on the brake pedal, then starts the vehicle, puts down the hand brake, and finally releases the brake pedal and releases the vehicle according to the surrounding traffic condition. In the process, unexpected situations can be met at any time, and the proper braking degree needs to be recovered at any time according to actual conditions. Therefore, the judgment of the intention of the driver is a key link, and in order to realize better starting quality, the intention of the driver needs to be monitored in real time, and accurate and correct judgment is given. According to the judged intention of the driver, the quantized ideal transmission ratio of the HMCVT can be given according to fuzzy reasoning. Due to the limitation of actual conditions such as dead zone characteristics and fluid leakage of the variable displacement pump, the actual output speed ratio of the transmission and an ideal transmission ratio (the reciprocal of the transmission ratio) have inevitable deviation, and in order to quickly, accurately and stably compensate the deviation, the invention provides a sliding mode variable structure starting control strategy based on an upper bound.
First, we take a certain commercial vehicle as an example, and determine the maximum gear ratio and the minimum gear ratio in the starting process according to the parameters of the commercial vehicle. The process is as follows:
wherein imaxIs the maximum transmission ratio; g is the maximum load capacity; f is rolling resistanceCoefficient αmaxIs the maximum climbing angle; r is the rolling radius of the wheel; t ismaxIs the engine maximum torque; i.e. i0Is the main reduction ratio, and η is the mechanical efficiency.
Wherein iminIs the minimum gear ratio; n isdaisuIs the engine idle speed; v is the starting vehicle speed.
By substituting commercial vehicle specific parameters we can get 7.051, 26.274.
Then, the intention of the driver is identified, a fuzzy control method is adopted, the angle and the speed of releasing the brake pedal are used as input, an ideal transmission ratio which accords with the intention of the driver is used as output, and a driver intention identification model is built.
According to the actual condition of the experimental vehicle, the rotating angle range [0,60 DEG ] that the brake pedal can rotate]Is recorded as theta ∈ [0,60 ° ]](ii) a According to the actual test situation, the angular velocity range of the driver stepping on the brake pedal is [0,75 ° ]]S, is described as
The range of transmission ratio during the starting process is known as [7.051,26.274 ]]And is marked as i e [7.051,26.274 ]]。
After the ranges of the variables are determined, fuzzification processing is performed on the input variables theta and theta
According to practical experience in various driving conditions, the two input variables can be divided into 5 fuzzy domains respectively, namely [0 and 12%]，[12,24]，[24,36]，[36,48]，[48,60]And [0,15]，[15,30]，[30,45]， [45,60]，[60,75](ii) a The output variable i can be divided into 5 fuzzy domains [7.051, 10%]， [10,14]，[14,18]，[18,22]，[22,26.274]. For 5 fuzzy domains divided by the input variable and the output variable, the corresponding fuzzy languages are VS (very small), S (small), M (medium), B (large) and VB (very large), respectively.
Then, the fuzzy domains of the input variable and the output variable are quantized, and the fuzzy domains are divided into 5 quantization levels according to the divided 5 regions, namely, the abscissa interval of the membership function is [0, 5]]Respectively obtained quantization factors are respectively kθ＝1/12，
ki＝1/18。
After the fuzzification processing is carried out on the original data, a fuzzy rule is formulated, the output variable is a transmission ratio, and the meanings represented by 5 grades are as follows: VS corresponds to slow start, S corresponds to normal steady start, M corresponds to rapid start, B corresponds to full load start, and VB corresponds to the extreme case of full load start on a sloping road. The angular displacement of the brake pedal and the angular speed of the brake pedal with two input variables comprehensively reflect the intention of a driver, and simultaneously, the output can be in accordance with the ideal transmission ratio of the actual operation condition. For the specific form of the rule, based on the test calibration under the NEDC cycle conditions, we summarize the fuzzy rule table as shown in table 2:
TABLE 2 fuzzy rule Table
After the fuzzy rule table is determined, the membership function is determined, and in order to ensure that the fuzzy process is accurate and rapid and has good real-time performance, the Gaussian membership function is used as the membership function of the input variable and the output variable.
As shown in fig. 2-3, the image of the membership function of all fuzzy variables is subjected to an output variable defuzzification process after the membership function is determined, and an output surface graph of the two-input one-output fuzzy inference system can be obtained by adopting a relatively common maximum and minimum value method and according to the fuzzy rules in table 2.
Through the fuzzy reasoning process, the ideal transmission ratio which accords with the actual running condition can be determined, and then the tracking problem of the ideal transmission ratio is solved.
The starting process belongs to a pure hydraulic mode. And the mathematical model of the starting stage of the HMCVT can be obtained as follows:
wherein, the working volume of the oil is the working volume of the oil; the elastic modulus of the oil is shown; is the load moment of inertia of the output shaft; is the moment of inertia of the motor shaft; motor viscous damping; a customized load torque for the output shaft; is the maximum displacement of the pump; is the displacement ratio of the pump; the displacement of the motor is quantified; characteristic parameters of the front planet row; characteristic parameters of the front planet row; is the output shaft speed; is the output shaft speed; is the total leakage coefficient; the viscosity of the oil is shown; the gear transmission ratio between the input shaft and the intermediate shaft is adopted; the gear transmission ratio between the input shaft and the intermediate shaft is adopted; the pressure difference between the high-pressure oil circuit and the low-pressure oil circuit.
The following can be obtained by further summarizing the above formula:
wherein the content of the first and second substances,
σ is the speed ratio. On the basis, the laplace transform is carried out to obtain:
with the pump displacement ratio epsilon as input and the speed ratio sigma as output, the transfer function can be written as:
wherein the content of the first and second substances,
according to the transfer function model, the transfer function model can be converted into a state space equation form, the displacement ratio epsilon of the variable pump is used as an input variable, the final speed ratio sigma of the HMCVT is used as an output variable, and the state space equation is as follows:
x2＝-0.00008136·x1-0.001416·x2+u；
namely, after the ideal transmission ratio is determined by a fuzzy control mode, a sliding mode variable structure method based on an upper bound is adopted for tracking. The design flow of the sliding mode variable structure controller is as follows:
the error between the ideal gear ratio and the actual gear ratio is first determined as:
e＝ε-ε*；
then, the switching function of the slip control is determined as:
where c > 0, the value here is 0.7. The controller can be designed to: the transmission ratio regulation and control calculation formula is as follows:
wherein u is the displacement ratio, and f is-0.00008136 x1-0.001416·x2；x1For speed ratio, x2Is the derivative of the speed ratio, η is the mechanical efficiency.
The controller may be proven to be stable according to lyapunov's theorem. Therefore, the variable displacement pump can be continuously adjusted and corrected according to the tracking error of the transmission ratio, the displacement ratio of the variable displacement pump can be adjusted in real time, and the transmission ratio of the whole HMCVT can be regulated and controlled.
The invention provides a new HMCVT structural form which accords with the running condition characteristics of commercial vehicles, and develops a sliding mode variable structure starting control strategy based on the upper bound on the basis.
The invention is based on the traditional tractor speed changer, and is greatly improved, so that the commercial vehicle HMCVT can be freely switched among 3 modes of pure hydraulic drive, pure mechanical drive and hydraulic mechanical drive. Compared with the traditional AMT and manual gear mode, the automatic transmission can better adapt to various driving conditions and improve the fuel economy.
Compared with the traditional AMT and manual gear modes, the sliding mode variable structure starting control strategy based on the upper bound is developed, the starting smoothness can be improved, the starting response time is shortened, the starting intention of a driver is more met, and the starting performance of the commercial vehicle is fundamentally improved.
The invention verifies that the improved HMCVT is suitable for commercial vehicles, can greatly improve the transmission efficiency, and can be popularized in a large scale, thereby greatly reducing the pressure of energy and environmental protection.
While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in various fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.
Claims (10)
1. A commercial vehicle hydromechanical continuously variable transmission, comprising:
a mechanical input shaft;
the first gear is fixedly sleeved on the mechanical input shaft and can rotate along with the mechanical input shaft;
the mechanical transmission mechanism is sleeved on the mechanical input shaft in an empty mode and can freely rotate around the mechanical input shaft;
a hydraulic drive shaft disposed parallel to the mechanical input shaft;
the second gear is fixedly sleeved on the hydraulic transmission shaft, is meshed with the first gear and can drive the hydraulic transmission shaft to rotate;
the input end of the hydraulic speed regulating mechanism is connected with the hydraulic transmission shaft;
the mechanical input shaft can be driven to rotate by the rotary power provided by the engine, and the hydraulic transmission shaft is driven to rotate;
a planetary gear mechanism capable of converging the rotational power of the mechanical transmission mechanism and the hydraulic speed regulation mechanism and outputting the rotational power through an output end of the planetary gear mechanism;
a first clutch mechanism provided between the mechanical input shaft and the planetary gear mechanism, and capable of selectively coupling or decoupling the mechanical input shaft and the planetary gear mechanism;
a second clutch mechanism provided between the mechanical input shaft and the planetary gear mechanism output end, capable of selectively coupling or decoupling the mechanical input shaft and the planetary gear mechanism output end;
the third clutch mechanism is arranged between the hydraulic transmission shaft and the hydraulic speed regulating mechanism and can enable the hydraulic transmission shaft and the hydraulic speed regulating mechanism to be selectively combined or separated;
a reversing shaft;
a fourth clutch mechanism which is arranged between the output end of the hydraulic speed regulating mechanism and the reversing shaft and can selectively combine or separate the reversing shaft and the third clutch mechanism;
a power take-off shaft;
and a fifth clutch mechanism provided between the mechanical transmission mechanism and the power output shaft, and capable of selectively coupling or decoupling the power output shaft and the mechanical transmission mechanism.
2. The commercial vehicle hydro-mechanical continuously variable transmission of claim 1, wherein the planetary gear mechanism comprises:
a first ring gear;
the first sun gear is connected with an output shaft of the hydraulic speed regulating mechanism;
a plurality of first planet gears distributed on the outer side of the first sun gear in a circumferential array and respectively meshed with the first sun gear and the first gear ring;
the first planet gear is rotatably supported on the first planet carrier, and the first planet carrier can receive the rotating power of the mechanical driving shaft and drive the first planet gear to rotate around the first sun gear so as to drive the first gear ring to rotate;
a second carrier integrally connected to the first ring gear;
a second ring gear;
the second sun gear is connected with an output shaft of the hydraulic speed regulating mechanism;
a plurality of second planet gears rotatably supported on the second planet carrier, distributed in a circumferential array outside the second sun gear, and respectively meshed with the second sun gear and the second ring gear;
a planetary gear output shaft connected with the second carrier.
3. The commercial vehicle hydromechanical continuously variable transmission according to claim 2, wherein the mechanical transmission mechanism includes:
at least one idler gear, which is freely rotatable around the mechanical input shaft, and is freely sleeved on the mechanical input shaft;
at least one hollow gear, which is freely sleeved on the mechanical input shaft and can freely rotate around the mechanical input shaft;
at least one planet carrier meshing gear which is fixedly sleeved on the first planet carrier and is meshed with the empty gear;
and the connecting gear is fixedly sleeved on the second gear ring and is meshed with the hollow gear.
4. The commercial vehicle hydro-mechanical continuously variable transmission of claim 3, wherein the hydraulic governor mechanism comprises:
the variable hydraulic pump is connected with the hydraulic transmission shaft;
a hydraulic motor in communication with the variable displacement hydraulic pump, the variable displacement hydraulic pump being capable of driving the hydraulic motor to rotate.
5. The commercial vehicle hydro-mechanical continuously variable transmission of claim 1, wherein the first, second, third and fourth clutching mechanisms are each an engagement clutch.
6. The commercial vehicle hydro-mechanical continuously variable transmission of claim 1, further comprising: and the combined output mechanism is arranged between the reverse shaft and the power output shaft.
7. A starting control method for a hydraulic mechanical continuously variable transmission of a commercial vehicle is characterized by comprising the following steps:
inputting the releasing angle and the releasing speed of the brake pedal into a fuzzy controller, and obtaining an ideal transmission ratio combining the intention of a driver after analysis;
calculating the error of the ideal transmission ratio and the actual transmission ratio, and determining a switching function of the slip control according to the error;
and obtaining a transmission ratio regulation calculation formula according to the switching function of the sliding control, thereby realizing the real-time regulation of the transmission ratio of the mechanical stepless speed changer.
8. The starting control method of the hydraulic mechanical continuously variable transmission for commercial vehicles according to claim 7, wherein the fuzzy sets of the angle of brake pedal release, the speed of brake pedal release and the ideal gear ratio are { VS, S, M, B, VB }, VS denotes small, S denotes small, M denotes medium, B denotes large, VB denotes large, the angle of brake pedal release is divided into 5 fuzzy domains [0,12], [12,24], [24,36], [36,48], [48,60], the speed of brake pedal release is divided into 5 fuzzy domains [0,15], [15,30], [30,45, 60], [60,75], the ideal gear ratio is divided into 5 fuzzy domains [7.051,10], [10,14], [14,18], [18,22],[22,26.274].
9. The starting control method for a hydro-mechanical continuously variable transmission for a commercial vehicle according to claim 8, wherein the switching function of the slip control is:
where s is the switching function of the slip control, e is the difference between the ideal transmission ratio and the actual transmission ratio, e ═ epsilon-epsilon*With ε being the ideal transmission ratio ε*C is the coefficient for the actual gear ratio.
10. The starting control method of the hydro-mechanical continuously variable transmission for commercial vehicles according to claim 9, characterized in that the gear ratio regulation calculation formula is:
wherein u is the displacement ratio, and f is-0.00008136 x1-0.001416·x2；x1For speed ratio, x2Is the derivative of the speed ratio, η is the mechanical efficiency.
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| CN104149779A (en) * | 2014-07-08 | 2014-11-19 | 江苏大学 | Vehicle power matching system with hydraulic mechanical continuously-variable transmission |
| KR20150026474A (en) * | 2013-09-03 | 2015-03-11 | 엘에스엠트론 주식회사 | Transmission apparatus of vehicle and controlling method thereof |
| CN107143638A (en) * | 2017-05-02 | 2017-09-08 | 北京理工大学 | Hydraulic machinery is combined continuously variable transmittion |
| CN110953318A (en) * | 2019-11-06 | 2020-04-03 | 江苏大学 | Mechanical hydraulic composite transmission device and control method |
| CN211924834U (en) * | 2020-04-10 | 2020-11-13 | 吉林大学 | Hydraulic mechanical continuously variable transmission of commercial vehicle |
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| KR20150026474A (en) * | 2013-09-03 | 2015-03-11 | 엘에스엠트론 주식회사 | Transmission apparatus of vehicle and controlling method thereof |
| CN104149779A (en) * | 2014-07-08 | 2014-11-19 | 江苏大学 | Vehicle power matching system with hydraulic mechanical continuously-variable transmission |
| CN107143638A (en) * | 2017-05-02 | 2017-09-08 | 北京理工大学 | Hydraulic machinery is combined continuously variable transmittion |
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