AMT shift force control method without synchronizer based on speed difference coupling principle

Abstract

The present invention relates to an AMT synchronizer-free shift force control method based on the speed difference coupling principle, comprising the steps of: entering the main box shift state, obtaining input information; calculating the upshift top tooth speed difference; calculating the downshift top tooth speed difference; obtaining the basic shift force; obtaining the transmission oil temperature correction coefficient and the gear position correction coefficient; calculating the target shift force; calculating the duty ratio of the shift solenoid valve in the idle stroke stage; judging whether to enter the idle stroke stage; judging whether to enter the top tooth collision stage; judging whether to enter the gear buffer stage; judging whether the target gear position has been engaged. The present invention significantly reduces the impact and noise when the pneumatic actuator performs the shift action; greatly increases the service life of the engagement teeth; significantly reduces the torsional vibration energy of the power chain caused by the synchronizer-free shift, and improves the shift quality.

Description

Technical Field

[0001] The present invention relates to the technical field of AMT shift control, and in particular to an AMT synchronizer-free shift force control method based on a speed difference coupling principle. Background Art

[0002] As for commercial vehicle AMT shift actuators, there are generally three types: electronically controlled electric, electronically controlled hydraulic and electronically controlled pneumatic. Among them, electronically controlled pneumatic actuators are increasingly used in the field of commercial vehicle AMT due to their simple structure, high reliability, pollution-free and low cost. At present, domestic heavy-duty AMTs such as Fast, Wanliyang, Sinotruk and Dongfeng, and foreign heavy-duty AMTs such as ZFTraXon and VolVo I-shift all use pneumatic shift actuators.

[0003] There are two control modes for adjusting the position / speed of the shift cylinder: OnOff or PWM control. When the TCU issues a shift command, the solenoid valve adjusts the shift cylinder flow according to the control command, thereby adjusting the cylinder position / speed.

[0004] Existing shift force control methods are mostly designed for electronically controlled electric or electronically controlled hydraulic actuation. For example, the Chinese patent application with application number CN202110470502.0 and patent name "A sliding gear sleeve shift control method and vehicle based on electric shift actuator" proposes a control method for controlling the shift force in stages to reduce the impact of shifting and shorten the shifting time.

[0005] For example, the article "Analysis and Optimal Control of Gear Shifting Impact in Synchronizer-Free AMT of Electric Vehicles" designed a method of PWM control of shifting force.

[0006] For example, the article "Research on AMT Shift Force Control Based on High-Speed ​​Switching Valve" studies the control period and duty cycle parameter design method of the electronically controlled hydraulic shift actuator using PWM to control the shift force.

[0007] For non-synchronizer shifting, it is achieved through non-synchronous forced meshing. According to Poisson collision theory, in order to reduce the impact of non-synchronous meshing on the power chain, the normal speed of the meshing teeth before collision should be reduced as much as possible, that is, the axial speed difference and circumferential speed difference of the meshing teeth should be reduced.

[0008] On the other hand, Figure 1 As shown in Figure 1, the geometry of the meshing teeth and the initial collision phase difference of the meshing teeth have a great influence on the required shift force during collision. Without considering interference, if the initial collision phase difference is close to 0, the required shift force increases to speed up the misalignment, and if the initial collision phase difference is close to π, the required shift force decreases to reduce the impact of gear shifting.

[0009] As an energy transmission medium, compressed air has strong nonlinear characteristics. At the same time, the cylinder and solenoid valve have strong hysteresis. The pneumatic shifting operation time without synchronizer is often only 150 to 250ms, which makes it difficult to quickly and accurately adjust the position / speed of the pneumatic actuator.

[0010] The objective disadvantages of the prior art are:

[0011] 1. Most of the existing technologies are aimed at the shift force control of electric or hydraulic actuators, and the controlled object is the conical engagement teeth. There are few technical solutions for the dog gear shift of pneumatic actuators.

[0012] 2. The prior art shift force control method for dog gear shifting does not take into account the influence of the initial collision phase difference, resulting in large shift shock and noise.

[0013] 3. The existing control method based on position / speed closed-loop adjustment of shift force cannot adapt to the strong nonlinearity and time lag characteristics of the pneumatic system, and the consistency of the strategy is poor.

[0014] 4. The shift force in the prior art matches the dog tooth speed difference at the initial moment of the shift state, but does not estimate the dog tooth speed difference at the top tooth moment, which results in the shift force not being able to match the shift demand well, and is also prone to shift shock and noise. Summary of the invention

[0015] In view of the above problems, the present invention provides an AMT synchronizer-free shift force control method based on the speed difference coupling principle, which aims to significantly reduce the impact and noise when the pneumatic actuator performs the shifting action; greatly improve the service life of the engaging teeth; significantly reduce the torsional vibration energy of the power chain caused by the synchronizer-free shifting, and improve the shifting quality.

[0016] To solve the above problems, the technical solution provided by the present invention is:

[0017] A method for controlling the shift force of an AMT without a synchronizer based on the speed difference coupling principle comprises the following steps:

[0018] S100. Enter the main gearbox shift state, and then obtain input information; the input information includes shift type, current transmission oil temperature, current air pressure, current gear, target gear, target gear main gear ratio, intermediate shaft speed, output shaft speed, dog gear speed difference, shift position, target gear learning value, clutch feedback torque, vehicle mass, slope;

[0019] S200. According to the shift type, determine whether to shift up; then perform the following operations according to the determination result:

[0020] If the judgment result is upshift, execute S300;

[0021] If the judgment result is downshift, execute S400;

[0022] S300. Calculate the upshift top gear speed difference according to the current transmission oil temperature, the vehicle mass, the slope, the current gear, the target gear, the intermediate shaft speed, the output shaft speed, and the dog gear speed difference;

[0023] S400. Calculate the downshift top gear speed difference according to the current transmission oil temperature, the vehicle mass, the slope, the current gear, the target gear, the clutch feedback torque, the output shaft speed, and the dog gear speed difference;

[0024] S500. According to the upshift top gear speed difference, or the downshift top gear speed difference, and the current gear, a lookup operation is performed in a manually preset two-dimensional table to obtain a basic shift force;

[0025] S600. According to the current transmission oil temperature and the current gear position, a table lookup operation is performed in a manually preset two-dimensional table to obtain a transmission oil temperature correction coefficient and a gear position correction coefficient;

[0026] Then, according to the current air pressure, a table lookup operation is performed in a manually preset two-dimensional table to obtain the current maximum shift force;

[0027] S700. Calculate the target shift force;

[0028] S800. Calculate the duty ratio of the shift solenoid valve in the idle stroke stage;

[0029] S900. Determine whether the current shift state has entered the idle travel stage; then perform the following operations based on the determination result:

[0030] If the judgment result is that the idle stroke phase is entered, the current shift state is entered into the idle stroke phase; then the duty ratio of the shift solenoid valve in the current control phase is set to the duty ratio of the shift solenoid valve in the idle stroke phase; and then the shift solenoid valve is turned on;

[0031] If the judgment result is that the idle stroke stage is not entered, the current shift state is entered into the pressure building response stage; then the duty cycle of the shift solenoid valve in the current control stage is set to 100%; and then the shift solenoid valve is turned on;

[0032] S1000. Determine whether the current shift state has entered the top gear collision stage; then perform the following operations according to the determination result:

[0033] If the judgment result is that the top gear collision stage has been entered, the current shift state is entered into the top gear collision stage; then the top gear timer is initialized and starts timing, and the top gear position is recorded at the same time; then the duty cycle of the shift solenoid valve in the current control stage is set to 100%;

[0034] If the judgment result is that the top tooth collision stage is not entered, the current shift state is entered into the idle stroke stage; then the duty ratio of the shift solenoid valve in the current control stage is set to the duty ratio of the shift solenoid valve in the idle stroke stage;

[0035] S1100. Call the value of the top gear timer obtained in S1000 and the top gear position when the top gear collision ends; then determine whether the current shift state enters the gear-in buffer stage; then perform the following operations according to the determination result:

[0036] If the judgment result is that the gear-entry buffer stage is entered, the current gear-shifting state is entered into the gear-entry buffer stage; then the reverse solenoid valve is turned on; and then the duty cycle of the reverse solenoid valve is set to 100%;

[0037] If the judgment result is that the gear-in buffering stage is not entered, the reverse solenoid valve is kept in a closed state;

[0038] S1200. Determine whether the gear position has been engaged according to the gear shift position; and then perform the following operations according to the determination result:

[0039] If the judgment result is that the shift position has been engaged to the target gear position, closing the shift solenoid valve and the reverse solenoid valve;

[0040] If the judgment result is that the shift position has not yet reached the target gear, the shift solenoid valve is kept at the buffer stage duty cycle, and the reverse solenoid valve is closed until the target gear is reached;

[0041] S1300. End this main gearbox shift control process.

[0042] Preferably, the upshift top gear speed difference in S300 is the speed difference between the engaging tooth of the sliding gear sleeve and the engaging tooth of the target gear at the moment when the top gear of the gear is engaged, and is obtained by the following steps:

[0043] S310. Obtain the intermediate shaft speed and the output shaft speed; then calculate the intermediate shaft speed reduction rate and the output shaft speed reduction rate in the initial state of the shift by a sliding average filtering method;

[0044] S320. Obtain the current transmission oil temperature and the current gear position; then, according to the current gear position, call the current transmission oil temperature and the intermediate shaft deceleration rate in the initial state of the gear shift calculated in S310; then, look up the table to obtain the intermediate shaft deceleration speed difference; the intermediate shaft deceleration speed difference is the difference between the intermediate shaft speed in the initial state of the gear shift and the intermediate shaft speed at the time of the top gear collision; the table looked up is a two-dimensional table preset according to the transmission bench test;

[0045] S330. Obtain the vehicle mass and the slope; then call the output shaft deceleration rate calculated in S310 to calculate the output shaft deceleration speed difference, which is expressed as follows:

[0046] n_upOutSlip=fact_mass*fact_grad*w_OutRamp*t_esti

[0047] Wherein: n_upOutSlip is the output shaft speed difference; fact_mass is the vehicle mass correction coefficient; fact_grad is the slope correction coefficient; w_OutRamp is the output shaft speed reduction rate in the initial state of the shift; t_esti is the time difference from the initial moment of the shift to the moment of top tooth collision;

[0048] S340. Obtain the target gear main box speed ratio; then calculate the upshift top gear speed difference, expressed as follows:

[0049] n_upDogSlip=n_dogClthSlip+(n_upLaySlip / i_trggear-n_upOutSlip)

[0050] Among them: n_upDogSlip is the upshift top gear speed difference; n_dogClthSlip is the initial dog gear speed difference of the gear shift; i_trggear is the target gear main box speed ratio; n_upLaySlip is the intermediate shaft downshift speed difference obtained by looking up the table in S320.

[0051] Preferably, the downshift top gear speed difference in S400 is the speed difference between the engaging teeth of the sliding gear sleeve and the engaging teeth of the target gear at the moment when the top teeth of the gear engage, which is obtained by the following steps:

[0052] S410. Obtain the output shaft speed; then calculate the output shaft speed reduction rate in the initial state of the shift by the sliding average filtering method;

[0053] S420. Obtain the current transmission oil temperature, the clutch feedback torque, and the current gear position; call the current transmission oil temperature and the clutch feedback torque according to the current gear position; then look up the table to obtain the intermediate shaft speed difference; the intermediate shaft speed difference is the difference between the intermediate shaft speed in the initial state of the gear shift and the intermediate shaft speed at the moment of top gear collision; the clutch feedback torque is the clutch feedback torque at the end of the clutch secondary engagement state; the table looked up is a preset two-dimensional table;

[0054] S430. Obtain the vehicle mass and the slope; then call the output shaft speed reduction rate in the initial state of the shift calculated in S410 to calculate the output shaft speed reduction difference, which is expressed as follows:

[0055] n_dwOutSlip=fact_mass*fact_grad*w_OutRamp*t_esti

[0056] Wherein: n_dwOutSlip is the output shaft speed difference;

[0057] S440. Obtain the target gear main box speed ratio; then calculate the downshift top gear speed difference, expressed as follows:

[0058] n_dwDogSlip=n_dogClthSlip+(n_dwLaySlip / i_trggear-n_dwOutSlip)

[0059] Among them: n_dwDogSlip is the downshift top gear speed difference; n_dwLaySlip is the intermediate shaft downshift speed difference obtained by looking up the table in S420.

[0060] Preferably, the target shift force in S700 is expressed as follows:

[0061] F_d=fact_gear*fact_oil*F_b

[0062] Wherein: F_d is the target shift force; fact_gear is the gear correction coefficient; fact_oil is the transmission oil temperature correction coefficient; and F_b is the basic shift force obtained by looking up the table in S500.

[0063] Preferably, the duty cycle of the shift solenoid valve in the idle stroke stage in S800 is expressed as follows:

[0064] Duty_T2T=F_d / F_m

[0065] Wherein, Duty_T2T is the duty ratio of the shift solenoid valve in the idle stroke stage; F_m is the current maximum shift force obtained by looking up the table in S500.

[0066] Preferably, determining whether the current gear shifting state has entered the idle travel stage in S900 includes the following steps:

[0067] S910. Compare the absolute value of the shift position with the upper limit of the neutral threshold; then perform the following operations based on the comparison result:

[0068] If the absolute value of the shift position is greater than the neutral threshold upper limit, the result of the determination is that the vehicle enters the neutral travel stage;

[0069] If the absolute value of the shift position is not greater than the neutral threshold upper limit, the result of the determination is that the idle travel stage will not be entered;

[0070] Wherein: the absolute value of the shift position is the absolute value of the shift position sensor signal; the upper limit of the neutral threshold is a calibrated value.

[0071] Preferably, determining in S1000 whether the current shift state has entered the top gear collision stage comprises the following steps:

[0072] S1010. Determine whether the top gear condition is met; then perform the following operations based on the determination result:

[0073] If the top tooth condition is met, the judgment result is entering the top tooth collision stage;

[0074] If the top tooth condition is not met, the result of the judgment is that the top tooth collision stage is not entered;

[0075] The top gear condition is that the gear shift position does not reach the target gear position within a first preset time period, or the gear shift position change within a second preset time period is less than a manually preset calibration value.

[0076] Preferably, in S1000, the specific operation of initializing the top tooth timer is: setting the top tooth timer to 0.

[0077] Preferably, determining in S1100 whether the current gear shifting state enters the gear-entry buffering stage comprises the following steps:

[0078] S1110. Determine whether the buffer condition is met; then perform the following operations based on the determination result:

[0079] If the buffer condition is met, the judgment result is to enter the gear-entry buffer stage;

[0080] If the buffer condition is not met, the judgment result is not to enter the gear-entry buffer phase;

[0081] Among them, the buffer condition is: the top gear timer is greater than the third preset time length, the absolute value of the shift position is greater than the start buffer position, and the absolute value of the shift position is less than the end buffer position.

[0082] Preferably, the starting buffer position is expressed as follows:

[0083] y_buffSt=|y_T2T|+y_offset1

[0084] Wherein: y_buffSt is the starting buffer position; y_T2T is the top tooth position; y_offset1 is the manually preset calibration value;

[0085] The end buffer position is expressed as follows:

[0086] y_buffEn=|y_target|-y_offset2

[0087] Among them: y_buffEn is the end buffer position; y_target is the target gear learning value; y_offset2 is the manually preset calibration value.

[0088] Compared with the prior art, the present invention has the following advantages:

[0089] 1. The present invention significantly reduces the impact and noise when the pneumatic actuator performs the shifting action;

[0090] 2. The present invention greatly increases the service life of the engaging teeth;

[0091] 3. The present invention also significantly reduces the torsional vibration energy of the power chain caused by shifting without a synchronizer, thereby improving the shifting quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0092] Figure 1 It is the force diagram of top tooth collision;

[0093] Figure 2 It is a schematic diagram of a main gearbox shift control phase curve of a specific embodiment of the present invention;

[0094] Figure 3 It is a schematic diagram of a flow chart of a specific embodiment of the present invention.

[0095] Among them: Figure 1 In the equation, F_d is the shift force; F_f is the friction force on the sliding gear sleeve; ω gear is the target gear engagement ring gear speed; ω slv is the rotation speed of the sliding gear sleeve; θ is the phase difference between the target gear engagement tooth and the sliding gear sleeve engagement tooth. DETAILED DESCRIPTION

[0096] The present invention is further explained below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0097] It should be noted that the basic principles of the present invention are as follows:

[0098] like Figure 2As shown, the present invention divides the gear shifting process into a pressure building response stage (OT1), an idle travel stage (T1T2), a top tooth collision stage (T2T3), a gear entry buffer stage (T3T6) and a gear engagement stage (T6T7) according to the time sequence.

[0099] in:

[0100] In the pressure building response stage, the shift force is controlled to overcome the resistance of the self-locking mechanism to achieve rapid response; before the top tooth collision, in order to reduce the shift shock and noise, the shift force is controlled to meet the minimum shift force principle, that is, when the top tooth is collided, the shift force is not less than the sum of the axial reaction force and friction resistance generated by the collision of the engaging teeth, that is, Figure 1 In this case, F_d>=F_u+F_f.

[0101] During the top tooth collision stage, the initial collision phase difference is estimated according to the top tooth time and the shift force is adjusted to speed up the tooth shifting and shorten the gear shifting time.

[0102] During the gear-entry buffering stage, the timing and closing conditions for opening the reverse buffering are designed according to the top gear time; during the gear-engaging stage, the opening and closing of the solenoid valve are determined according to the gear shift position.

[0103] In addition, in order to achieve a good match between the shift force and the dog tooth speed difference during the top tooth collision phase, the present invention also proposes a synchronizer-free shift dog tooth speed difference estimation method that takes into account the influence of mass slope.

[0104] The following describes in detail the method of using the present invention:

[0105] like Figure 3 As shown, a method for controlling the shift force of an AMT without a synchronizer based on the speed difference coupling principle comprises the following steps:

[0106] S100. Enter the main gear shifting state, and then obtain input information; the input information includes shift type, current transmission oil temperature, current air pressure, current gear, target gear, target gear main gear ratio, intermediate shaft speed, output shaft speed, dog gear speed difference, shift position, target gear learning value, clutch feedback torque, vehicle mass, and slope.

[0107] S200. Determine whether to shift up according to the gear shift type; then perform the following operations according to the determination result:

[0108] If the judgment result is upshift, S300 is executed.

[0109] If the judgment result is downshifting, S400 is executed.

[0110] S300. Calculate the upshift top gear speed difference based on the current transmission oil temperature, vehicle mass, slope, current gear, target gear, intermediate shaft speed, output shaft speed, and dog gear speed difference.

[0111] In this specific embodiment, the upshift top gear speed difference in S300 is the speed difference between the engaging tooth of the sliding gear sleeve and the engaging tooth of the target gear at the moment of the top gear collision, which is obtained by the following steps:

[0112] S310. Obtain the intermediate shaft speed and the output shaft speed; then calculate the intermediate shaft speed reduction rate and the output shaft speed reduction rate in the initial state of the shift by using a sliding average filtering method.

[0113] S320. Obtain the current transmission oil temperature and the current gear position; then, based on the current gear position, call the current transmission oil temperature and the intermediate shaft deceleration rate in the initial state of the gear shift calculated in S310; then look up the table to obtain the intermediate shaft deceleration speed difference; the intermediate shaft deceleration speed difference is the difference between the intermediate shaft speed in the initial state of the gear shift and the intermediate shaft speed at the moment of top tooth collision; the table looked up is a two-dimensional table preset according to the transmission bench test.

[0114] S330. Obtain the vehicle mass and slope; then call the output shaft deceleration rate calculated in S310 to calculate the output shaft deceleration speed difference, expressed as formula (1):

[0115] n_upOutSlip=fact_mass*fact_grad*w_OutRamp*t_esti(1)

[0116] Among them: n_upOutSlip is the output shaft speed difference; fact_mass is the vehicle mass correction coefficient; fact_grad is the slope correction coefficient; w_OutRamp is the output shaft speed reduction rate in the initial state of the shift; t_esti is the time difference from the initial moment of the shift to the moment of top tooth collision;

[0117] It should be noted that in actual work, t_esti is an empirical estimate.

[0118] S340. Obtain the target gear main box speed ratio; then calculate the upshift top gear speed difference, expressed as formula (2):

[0119] n_upDogSlip=n_dogClthSlip+(n_upLaySlip / i_trggear-n_upOutSlip)(2)

[0120] Among them: n_upDogSlip is the top gear speed difference of the upshift; n_dogClthSlip is the initial dog gear speed difference of the shift; i_trggear is the target gear main box speed ratio; n_upLaySlip is the intermediate shaft downshift speed difference obtained by looking up the table in S320.

[0121] S400. Calculate the downshift top gear speed difference according to the current transmission oil temperature, vehicle mass, slope, current gear, target gear, clutch feedback torque, output shaft speed, and dog gear speed difference.

[0122] In this specific embodiment, the speed difference of the top gear of the downshift in S400 is the speed difference between the engaging tooth of the sliding gear sleeve and the engaging tooth of the target gear at the moment of the top gear collision, which is obtained by the following steps:

[0123] S410. Obtain the output shaft speed; then calculate the output shaft speed reduction rate in the initial state of the shift by using a sliding average filtering method.

[0124] S420. Obtain the current transmission oil temperature, clutch feedback torque, and current gear position; according to the current gear position, call the current transmission oil temperature and clutch feedback torque; then look up the table to obtain the intermediate shaft speed difference; the intermediate shaft speed difference is the difference between the intermediate shaft speed in the initial state of gear shifting and the intermediate shaft speed at the moment of top gear collision; the clutch feedback torque is the clutch feedback torque at the end of the secondary engagement state of the clutch; the table looked up is a preset two-dimensional table.

[0125] S430. Obtain the vehicle mass and slope; then call the output shaft speed reduction rate of the initial shift state calculated in S410 to calculate the output shaft speed reduction difference, which is expressed as formula (3):

[0126] n_dwOutSlip=fact_mass*fact_grad*w_OutRamp*t_esti (3)

[0127] Among them: n_dwOutSlip is the speed difference of the output shaft.

[0128] S440. Obtain the target gear main box speed ratio; then calculate the downshift top gear speed difference, expressed as formula (4):

[0129] n_dwDogSlip=n_dogClthSlip+(n_dwLaySlip / i_trggear-n_dwOutSlip) (4)

[0130] Among them: n_dwDogSlip is the speed difference of the top gear when downshifting; n_dwLaySlip is the speed difference of the intermediate shaft downshifting obtained by looking up the table in S420.

[0131] S500. According to the top gear speed difference of the upshift gear, or the top gear speed difference of the downshift gear, and the current gear, a lookup operation is performed in a manually preset two-dimensional table to obtain a basic shift force;

[0132] S600. According to the current transmission oil temperature and the current gear position, a lookup operation is performed in a manually preset two-dimensional table to obtain a transmission oil temperature correction coefficient and a gear position correction coefficient.

[0133] Then, according to the current air pressure, a lookup operation is performed in a manually preset two-dimensional table to obtain the current maximum shift force.

[0134] S700. Calculate and obtain target shifting force.

[0135] In this specific embodiment, the target shift force in S700 is expressed as follows:

[0136] F_d=fact_gear*fact_oil*F_b (5)

[0137] Wherein: F_d is the target shift force; fact_gear is the gear correction coefficient; fact_oil is the transmission oil temperature correction coefficient; F_b is the basic shift force obtained by looking up the table in S500.

[0138] S800. Calculate the duty ratio of the shift solenoid valve in the idle stroke stage.

[0139] In this specific embodiment, the duty cycle of the shift solenoid valve in the idle stroke stage of S800 is expressed as follows:

[0140] Duty_T2T=F_d / F_m (6)

[0141] Among them, Duty_T2T is the duty cycle of the shift solenoid valve in the idle stroke stage; F_m is the current maximum shift force obtained by looking up the table in S500.

[0142] S900. Determine whether the current shift state has entered the idle travel stage; then perform the following operations based on the determination result:

[0143] If the judgment result is entering the idle stroke stage, the current shift state enters the idle stroke stage; then the shift solenoid valve duty cycle of the current control stage is set to the shift solenoid valve duty cycle of the idle stroke stage, that is, Duty1 = Duty_T2T; and then the shift solenoid valve is turned on.

[0144] If the judgment result is that the idle stroke stage is not entered, the current shift state enters the pressure building response stage; then the duty cycle of the shift solenoid valve in the current control stage is set to 100%, that is, Duty1=100%; and then the shift solenoid valve is turned on.

[0145] In this specific embodiment, determining whether the current gear shift state has entered the idle travel stage in S900 includes the following steps:

[0146] S910. Compare the absolute value of the gear shift position y_gear with the upper limit of the neutral threshold y_upThres; then perform the following operations according to the comparison result:

[0147] If the absolute value of the shift position is greater than the upper limit of the neutral threshold, the result is that the vehicle enters the idle travel stage.

[0148] If the absolute value of the shift position is not greater than the upper limit of the neutral threshold, the result of the judgment is that the idle travel stage will not be entered.

[0149] Among them: the absolute value of the shift position is the absolute value of the shift position sensor signal; the upper limit of the neutral threshold is the calibrated value.

[0150] S1000. Determine whether the current gear shift state has entered the top gear collision stage; then perform the following operations based on the determination result:

[0151] If the judgment result is that the top gear collision stage has been entered, the current gear shifting state will enter the top gear collision stage; then the top gear timer timer is initialized and starts timing, and the top gear position y_T2T is recorded at the same time; then the duty cycle of the gear shifting solenoid valve in the current control stage is set to 100%, that is, Duty1=100%.

[0152] If the judgment result is that the top tooth collision stage is not entered, the current shift state is entered into the idle stroke stage; then the duty cycle of the shift solenoid valve in the current control stage is set to the duty cycle of the shift solenoid valve in the idle stroke stage, that is, Duty1 = Duty_T2T.

[0153] In this specific embodiment, determining whether the current gear shift state has entered the top gear collision stage in S1000 includes the following steps:

[0154] S1010. Determine whether the top gear condition is met; then perform the following operations based on the determination result:

[0155] If the top tooth condition is met, the judgment result is entering the top tooth collision stage.

[0156] If the top tooth condition is not met, the result of the judgment is that the top tooth collision stage will not be entered.

[0157] The top gear condition is: the gear shift position does not reach the target gear position within a first preset time length t_max, or the gear shift position change Δy_free within a second preset time length t_crash is less than a manually preset calibration value.

[0158] In this specific embodiment, in S1000, the specific operation of initializing the top tooth timer is: setting the top tooth timer to 0, that is, timer=0.

[0159] S1100. Call the value of the top gear timer obtained in S1000 and the top gear position when the top gear collision ends; then determine whether the current shift state enters the gear-in buffer stage; then perform the following operations based on the determination result:

[0160] If the judgment result is entering the gear-entry buffer stage, the current gear shift state enters the gear-entry buffer stage; then the reverse solenoid valve is turned on; and then the duty cycle of the reverse solenoid valve is set to 100%, that is, Duty2=100%.

[0161] If the judgment result is that the gear-in buffering stage will not be entered, the reverse solenoid valve will be kept closed.

[0162] It should be noted that when the reverse solenoid valve is turned on, the force acting on the cylinder piston is opposite to the force acting on the cylinder piston when the shift solenoid valve is turned on.

[0163] In this specific embodiment, determining whether the current gear shift state has entered the gear-entry buffering stage in S1100 includes the following steps:

[0164] S1110. Determine whether the buffer condition is met; then perform the following operations based on the determination result:

[0165] If the buffering condition is met, the judgment result is entering the gear-up buffering stage.

[0166] If the buffering condition is not met, the judgment result is that the gear-entry buffering stage will not be entered.

[0167] Among them, the buffering conditions are: the top gear timer is greater than the third preset time length t_buffer, the absolute value of the shift position is greater than the starting buffer position y_buffSt, and the absolute value of the shift position is less than the ending buffer position y_buffEn.

[0168] In this specific embodiment, the starting buffer position is expressed as follows:

[0169] y_buffSt=|y_T2T|+y_offset1 (7)

[0170] Among them: y_buffSt is the starting buffer position; y_T2T is the top tooth position; y_offset1 is the manually preset calibration value.

[0171] The end buffer position is expressed as follows:

[0172] y_buffEn=|y_target|-y_offset2 (8)

[0173] Among them: y_buffEn is the end buffer position; y_target is the target gear learning value; y_offset2 is the manually preset calibration value.

[0174] S1200. Determine whether the gear position has been reached according to the gear shift position; then perform the following operations according to the determination result:

[0175] If the judgment result is that the shift position has been engaged to the target gear, the shift solenoid valve and the reverse solenoid valve are closed.

[0176] If the judgment result is that the shift position has not yet reached the target gear, the shift solenoid valve is kept at the buffer stage duty cycle, and the reverse solenoid valve is closed until the target gear is reached.

[0177] S1300. End this main gearbox shift control process.

[0178] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0179] The disclosed embodiments are described above to enable any person skilled in the art to implement or use the present invention. Various modifications of these embodiments are obvious to those skilled in the art, and the general principles defined herein may also be applied to other embodiments without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0180] The above description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," is explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

[0181] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for controlling the shift force of an AMT without a synchronizer based on the principle of speed difference coupling, characterized in that: The following steps are involved: S100. Enter the main gearbox shift state, and then obtain input information; the input information includes shift type, current transmission oil temperature, current air pressure, current gear, target gear, target gear main gear ratio, intermediate shaft speed, output shaft speed, dog gear speed difference, shift position, target gear learning value, clutch feedback torque, vehicle mass, slope; S200. According to the shift type, determine whether to shift up; then perform the following operations according to the determination result: If the judgment result is upshift, execute S300; If the judgment result is downshift, execute S400; S300. Calculate the upshift top gear speed difference according to the current transmission oil temperature, the vehicle mass, the slope, the current gear, the target gear, the intermediate shaft speed, the output shaft speed, and the dog gear speed difference; S400. Calculate the downshift top gear speed difference according to the current transmission oil temperature, the vehicle mass, the slope, the current gear, the target gear, the clutch feedback torque, the output shaft speed, and the dog gear speed difference; S500. According to the upshift top gear speed difference, or the downshift top gear speed difference, and the current gear, a lookup operation is performed in a manually preset two-dimensional table to obtain a basic shift force; S600. According to the current transmission oil temperature and the current gear position, a table lookup operation is performed in a manually preset two-dimensional table to obtain a transmission oil temperature correction coefficient and a gear position correction coefficient; Then, according to the current air pressure, a table lookup operation is performed in a manually preset two-dimensional table to obtain the current maximum shift force; S700. Calculate the target shift force; S800. Calculate the duty ratio of the shift solenoid valve in the idle stroke stage; S900. Determine whether the current shift state has entered the idle travel stage; then perform the following operations based on the determination result: If the judgment result is that the idle stroke phase is entered, the current shift state is entered into the idle stroke phase; then the duty ratio of the shift solenoid valve in the current control phase is set to the duty ratio of the shift solenoid valve in the idle stroke phase; and then the shift solenoid valve is turned on; If the judgment result is that the idle stroke stage is not entered, the current shift state is entered into the pressure building response stage; then the duty cycle of the shift solenoid valve in the current control stage is set to 100%; and then the shift solenoid valve is turned on; S1000. Determine whether the current shift state has entered the top gear collision stage; then perform the following operations according to the determination result: If the judgment result is that the top gear collision stage has been entered, the current shift state is entered into the top gear collision stage; then the top gear timer is initialized and starts timing, and the top gear position is recorded at the same time; then the duty cycle of the shift solenoid valve in the current control stage is set to 100%; If the judgment result is that the top tooth collision stage is not entered, the current shift state is entered into the idle stroke stage; then the duty ratio of the shift solenoid valve in the current control stage is set to the duty ratio of the shift solenoid valve in the idle stroke stage; S1100. Call the value of the top gear timer obtained in S1000 and the top gear position when the top gear collision ends; then determine whether the current shift state enters the gear-in buffer stage; then perform the following operations according to the determination result: If the judgment result is that the gear-entry buffer stage is entered, the current gear-shifting state is entered into the gear-entry buffer stage; and then the reverse solenoid valve is turned on; Then set the duty cycle of the reverse solenoid valve to 100%; If the judgment result is that the gear-in buffering stage is not entered, the reverse solenoid valve is kept in a closed state; S1200. Determine whether the gear position has been engaged according to the gear shift position; and then perform the following operations according to the determination result: If the judgment result is that the shift position has been engaged to the target gear position, closing the shift solenoid valve and the reverse solenoid valve; If the judgment result is that the shift position has not yet reached the target gear, the shift solenoid valve is kept at the buffer stage duty cycle, and the reverse solenoid valve is closed until the target gear is reached; S1300. End this main gearbox shift control process.

2. The AMT synchronizer-free shift force control method based on the speed difference coupling principle according to claim 1, characterized in that: The upshift top gear speed difference in S300 is the speed difference between the engaging gear of the sliding gear sleeve and the engaging gear of the target gear at the moment of the top gear collision, and is obtained by the following steps: S310. Obtain the intermediate shaft speed and the output shaft speed; then calculate the intermediate shaft speed reduction rate and the output shaft speed reduction rate in the initial state of the shift by a sliding average filtering method; S320. Obtain the current transmission oil temperature and the current gear position; then, according to the current gear position, call the current transmission oil temperature and the intermediate shaft deceleration rate in the initial state of the gear shift calculated in S310; then, look up the table to obtain the intermediate shaft deceleration speed difference; the intermediate shaft deceleration speed difference is the difference between the intermediate shaft speed in the initial state of the gear shift and the intermediate shaft speed at the time of the top gear collision; the table looked up is a two-dimensional table preset according to the transmission bench test; S330. Obtain the vehicle mass and the slope; then call the output shaft deceleration rate calculated in S310 to calculate the output shaft deceleration speed difference, which is expressed as follows: n_upOutSlip=fact_mass*fact_grad*w_OutRamp*t_esti Wherein: n_upOutSlip is the output shaft speed difference; fact_mass is the vehicle mass correction coefficient; fact_grad is the slope correction coefficient; w_OutRamp is the output shaft speed reduction rate in the initial state of the shift; t_esti is the time difference from the initial moment of the shift to the moment of top tooth collision; S340. Obtain the target gear main box speed ratio; then calculate the upshift top gear speed difference, expressed as follows: n_upDogSlip=n_dogClthSlip+(n_upLaySlip / i_trggear-n_upOutSlip) Among them: n_upDogSlip is the upshift top gear speed difference; n_dogClthSlip is the initial dog gear speed difference of the gear shift; i_trggear is the target gear main box speed ratio; n_upLaySlip is the intermediate shaft downshift speed difference obtained by looking up the table in S320.

3. The AMT synchronizer-free shift force control method based on the speed difference coupling principle according to claim 2, characterized in that: The downshift top gear speed difference in S400 is the speed difference between the engaging teeth of the sliding gear sleeve and the engaging teeth of the target gear at the moment when the top teeth of the gear engage, and is obtained by the following steps: S410. Obtain the output shaft speed; then calculate the output shaft speed reduction rate in the initial state of the shift by the sliding average filtering method; S420. Obtaining the current transmission oil temperature, the clutch feedback torque, and the current gear position; According to the current gear position, the current transmission oil temperature and the clutch feedback torque are called; then the intermediate shaft speed difference is obtained by looking up the table; the intermediate shaft speed difference is the difference between the intermediate shaft speed in the initial state of the gear shift and the intermediate shaft speed at the moment of top tooth collision; the clutch feedback torque is the clutch feedback torque at the end of the clutch secondary engagement state; the table looked up is a preset two-dimensional table; S430. Obtain the vehicle mass and the slope; then call the output shaft speed reduction rate in the initial state of the shift calculated in S410 to calculate the output shaft speed reduction difference, which is expressed as follows: n_dwOutSlip=fact_mass*fact_grad*w_OutRamp*t_esti Wherein: n_dwOutSlip is the output shaft speed difference; S440. Obtain the target gear main box speed ratio; then calculate the downshift top gear speed difference, expressed as follows: n_dwDogSlip=n_dogClthSlip+(n_dwLaySlip / i_trggear-n_dwOutSlip) Among them: n_dwDogSlip is the downshift top gear speed difference; n_dwLaySlip is the intermediate shaft downshift speed difference obtained by looking up the table in S420.

4. The AMT synchronizer-free shift force control method based on the speed difference coupling principle according to claim 3 is characterized in that: The target shift force in S700 is expressed as follows: F_d=fact_gear*fact_oil*F_b Wherein: F_d is the target shift force; fact_gear is the gear correction coefficient; fact_oil is the transmission oil temperature correction coefficient; and F_b is the basic shift force obtained by looking up the table in S500.

5. The AMT synchronizer-free shift force control method based on the speed difference coupling principle according to claim 4 is characterized in that: The duty cycle of the shift solenoid valve in the idle stroke stage described in S800 is expressed as follows: Duty_T2T=F_d / F_m Wherein, Duty_T2T is the duty ratio of the shift solenoid valve in the idle stroke stage; F_m is the current maximum shift force obtained by looking up the table in S500.

6. The AMT synchronizer-free shift force control method based on the speed difference coupling principle according to claim 5, characterized in that: In S900, judging whether the current gear shifting state has entered the idle travel stage includes the following steps: S910. Compare the absolute value of the shift position with the upper limit of the neutral threshold; then perform the following operations based on the comparison result: If the absolute value of the shift position is greater than the neutral threshold upper limit, the result of the determination is that the vehicle enters the neutral travel stage; If the absolute value of the shift position is not greater than the neutral threshold upper limit, the result of the determination is that the idle travel stage will not be entered; Wherein: the absolute value of the shift position is the absolute value of the shift position sensor signal; the upper limit of the neutral threshold is a calibrated value.

7. The AMT synchronizer-free shift force control method based on the speed difference coupling principle according to claim 6 is characterized in that: In S1000, determining whether the current shift state has entered the top gear collision stage includes the following steps: S1010. Determine whether the top gear condition is met; then perform the following operations based on the determination result: If the top tooth condition is met, the judgment result is entering the top tooth collision stage; If the top tooth condition is not met, the result of the judgment is that the top tooth collision stage is not entered; The top gear condition is that the gear shift position does not reach the target gear position within a first preset time period, or the gear shift position change within a second preset time period is less than a manually preset calibration value.

8. The AMT synchronizer-free shift force control method based on the speed difference coupling principle according to claim 7, characterized in that: In S1000, the specific operation of initializing the top tooth timer is: setting the top tooth timer to 0.

9. The AMT synchronizer-free shift force control method based on the speed difference coupling principle according to claim 8, characterized in that: S1100 determines whether the current gear shift state has entered the gear-entry buffering stage, including the following steps: S1110. Determine whether the buffer condition is met; then perform the following operations based on the determination result: If the buffer condition is met, the judgment result is to enter the gear-entry buffer stage; If the buffer condition is not met, the judgment result is not to enter the gear-entry buffer phase; Among them, the buffer condition is: the top gear timer is greater than the third preset time length, the absolute value of the shift position is greater than the start buffer position, and the absolute value of the shift position is less than the end buffer position.

10. The AMT synchronizer-free shift force control method based on the speed difference coupling principle according to claim 9, characterized in that: The starting buffer position is expressed as follows: y_buffSt=|y_T2T|+y_offset1 Wherein: y_buffSt is the starting buffer position; y_T2T is the top tooth position; y_offset1 is the manually preset calibration value; The end buffer position is expressed as follows: y_buffEn=|y_target|-y_offset2 Among them: y_buffEn is the end buffer position; y_target is the target gear learning value; y_offset2 is the manually preset calibration value.

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