CN112081913B

CN112081913B - AMT transmission variable parameter gear shifting process control method

Info

Publication number: CN112081913B
Application number: CN202010959292.7A
Authority: CN
Inventors: 王建华; 郭富强; 王琳; 张友坤; 郝春光; 卢延辉
Original assignee: China Yituo Group Corp Ltd
Current assignee: China Yituo Group Corp Ltd
Priority date: 2020-09-14
Filing date: 2020-09-14
Publication date: 2021-09-24
Anticipated expiration: 2040-09-14
Also published as: CN112081913A

Abstract

The invention discloses a method for controlling a parameter-variable gear shifting process of an AMT (automated mechanical transmission), which comprises the following steps of: according to the characteristic of the synchronizer gear shifting, a fuzzy control theory is adopted to automatically distinguish three stages in a gear shifting process. And secondly, different control strategies (speed and force) are adopted for different stages in the same gear shifting process, so that the effects of shortest gear shifting time and smooth gear shifting are achieved. And thirdly, the electric motor is used as a gear shifting executing element, and each gear has specific control parameters so as to adapt to the structural characteristics of different gears of the AMT. Content four, fault-tolerant function of shift process control. Whether the gear shifting process is smooth or not is judged by monitoring the working parameters of the motor, and protective measures can be taken when a fault occurs, so that the damage to mechanical parts is prevented.

Description

AMT transmission variable parameter gear shifting process control method

Technical Field

The invention relates to the technical field of automobile transmission, in particular to a method for controlling a parameter-variable gear shifting process of an AMT (automated mechanical transmission).

Background

In order to reduce the working strength of a driver and improve fuel economy, an automatic Transmission needs to be equipped in an automobile (or other vehicles), but a high-power vehicle (such as a truck, an engineering vehicle and a tractor) can only adopt an Automatic Mechanical Transmission (AMT), and the automatic Transmission changes a gear shifting mechanism of a manual Transmission into an automatic control device. The AMT transmission has the characteristics of simple structure, good production succession, low cost and reliable quality because the box body part continues to use the structure of a manual transmission, and is the preferred scheme of a high-power automatic transmission.

The key technology of the AMT is a control method of a gear shifting actuating mechanism, and no matter a pneumatic element or an electric element, the motion law of gear shifting action must be controlled according to the characteristics of the gear shifting process of the transmission, so that the smooth and quick gear shifting effect can be achieved.

The traditional gear shifting process of the mechanical manual transmission can be divided into two steps of gear selection and gear engagement, wherein when the gear is selected, a driver operates a gear shifting handle to select a shifting fork shaft to be shifted into the gear, and when the gear is engaged, the driver operates the handle to push the shifting fork shaft to be shifted to the corresponding gear.

The most common shift mode for a manual mechanical transmission is a synchronizer shift. The synchronizer is one of the most important parts in the gear shifting process of the transmission, and is characterized in that direct gear engagement cannot be realized, a synchronization time is needed, and different synchronization times are needed according to different gear rotation speed differences. In the synchronization process, the synchronizing ring and the inclined plane on the gear generate friction, and the friction torque enables the rotating speed of the gear to be meshed to be synchronized. The synchronizer shifting process can be divided into three stages, in the first stage, under the pushing of a shifting fork, the synchronizer moves axially away from a middle position to enable two friction surfaces of a friction element to be contacted, and the gear rotation speed difference generates friction torque to enable a locking element to rotate to a locking position to complete locking action. In the second stage, under the action of the continuously applied axial force (shifting force), the positive pressure of the friction surface is continuously increased (or maintained), the friction torque enables the angular speed of the friction pair to gradually approach, and when the rotation speed difference and the friction torque disappear, the synchronization process is completed. And in the third stage, after the friction torque disappears, axial thrust (gear shifting force) still exists on the locking element, the locking element can move along the locking inclined plane, the meshing sleeve overcomes the spring force of the sliding block and crosses the locking ring to be meshed with the meshing teeth of the gear synchronously, and smooth gear engagement is ensured because of almost no relative rotation speed.

The AMT transmission is characterized in that a gear shifting mechanism of a manual mechanical transmission is automatically transformed, so that a transmission structural form of automatic gear shifting is realized, and if a transmission part of the transmission still adopts a synchronizer gear shifting mode, gear shifting action must be adapted to the working characteristics of a synchronizer.

The AMT transmission belongs to non-power gear shifting, power is required to be cut off in the gear shifting process, and power is restored after gear shifting is completed. In the process, the target gear is shifted into the target gear when the rotating speeds of the target gear and the current gear are not consistent due to improper control, so that the phenomenon of 'asynchronous shock' is caused. The shifting impact not only reduces the shifting quality of the vehicle, but also directly influences the service life of the synchronizer. Therefore, the power interruption time in the AMT gear shifting process is shortened, and the key of the AMT gear shifting control is to inhibit gear shifting impact.

Disclosure of Invention

The invention aims to design and develop a method for controlling the parameter-variable gear shifting process of an AMT (automated mechanical transmission), which adopts a fuzzy control theory, automatically selects control parameters according to the position of a stage boundary point and the state parameters of a system, and realizes the stage control of a motor.

It is another object of the present invention to determine whether a shift was successful through redundancy.

The technical scheme provided by the invention is as follows:

a method for controlling a parameter-variable gear shifting process of an AMT transmission comprises the following steps:

step one, collecting a gear shifting handle signal and determining a target shifting fork shaft;

step two, the non-target shifting fork shaft is kept in a neutral gear;

step three, driving a target shifting fork shaft to complete gear shifting through a motor;

during the gear shifting process, the target declutch shift shaft movement speed in the first stage is V1, the target declutch shift shaft movement speed in the second stage is V2, the target declutch shift shaft movement speed in the third stage is V3, and V1 is more than V2, and V3 is more than V2;

wherein, a fuzzy controller is adopted to control the rotating speed of the motor;

respectively converting the load current, the difference between the main rotating speed and the auxiliary rotating speed and the rotating speed of the motor into quantization levels in a fuzzy domain;

inputting the load current and the main-auxiliary rotation speed difference into a fuzzy controller, wherein the load current in the fuzzy controller is divided into 3 grades, the main-auxiliary rotation speed difference is divided into 5 grades, the fuzzy controller outputs a motor rotation speed, and the motor rotation speed is divided into 3 grades;

and step four, judging whether the gear shifting is in place or not by adopting a redundancy judgment mode.

Preferably, the method further comprises the following steps:

the motors are respectively connected with the shifting fork shafts in a one-to-one correspondence manner;

the detection unit is arranged on the transmission and used for determining the state parameter of the transmission;

the transmission electronic control unit is connected with the plurality of motors, the detection unit and the vehicle display instrument and is used for controlling the plurality of motors;

and the CAN bus is arranged among the gear shifting handle, the plurality of motors, the detection unit, the transmission electronic control unit and the vehicle display instrument and is used for acquiring a gear shifting handle signal and transmitting a signal.

Preferably, the detection unit includes:

a first rotational speed sensor provided on an input shaft of the transmission for detecting a rotational speed of the input shaft of the transmission;

a second rotational speed sensor provided on the output shaft of the transmission for detecting a rotational speed of the output shaft of the transmission;

the displacement sensors are respectively arranged on the plurality of shifting fork shafts in a one-to-one correspondence manner and are used for detecting the displacement of the plurality of shifting fork shafts;

and the current sensors are respectively arranged on the motors in a one-to-one correspondence mode and are used for detecting load current.

Preferably, the range of the load current is [0, 2000], the range of the main-driven rotation speed difference is [ -2500, 2500], and the range of the motor rotation speed is [0, 200 ].

Preferably, the fuzzy set of load currents is { S, M, B }, the fuzzy set of primary and secondary rotational speed differences is { NB, NS, ZO, PS, PB }, and the fuzzy set of motor rotational speeds is { S, M, B }.

Preferably, the membership function of the input signal is a gaussian membership function, and the calculation formula is as follows:

preferably, the membership function of the output signal is a triangular membership function, and the calculation formula is as follows:

preferably, the control rule of the fuzzy controller is as follows:

if the load current input is B, the rotating speed output of the motor is S, namely the rotating speed of the motor is slow;

if the load current input is S, the motor rotating speed output is B, namely the motor rotating speed is high.

Preferably, in the fourth step, redundancy determination is performed through the number of control pulses of the motor, displacement of the shifting fork, the main-driven rotation speed ratio of the transmission and the number of load current:

when gear shifting is completed and the detection unit works normally, the control pulse number of the motor is consistent with the pulse number required by the gear shifting stroke; the displacement of the shifting fork and the corresponding gear distance value are within +/-0.1 mm; the main-driven rotation speed ratio of the transmission is consistent with the gear transmission ratio; the value of the load current and the control current value when the transmission is in the hitching gear are less than 1A.

Preferably, in the second step, the first stage is a process that the shifting fork drives the coupling sleeve to move from the neutral position to be in contact with the lock ring of the gear ring to be coupled;

the second stage is a synchronization process of the synchronizer;

and the third stage is the process that the combination sleeve passes over the lock ring and is completely meshed with the gear ring to be combined after the synchronization is finished.

The invention has the following beneficial effects:

(1) according to the electric load characteristics of the motor, the gear shifting action process of the motor is known by monitoring the load current of the motor, the time when the synchronous conical rings start to rub and finish synchronously is automatically analyzed, and a control strategy can be modified by a control system; and (4) automatically selecting control parameters according to the position of the stage dividing point and the state parameters of the system by adopting a fuzzy control theory.

(2) Rotation information (turning angle and rotating speed control targets, driving current limitation and whether the motor is locked or not) of the motor is fed back through a CAN bus, so that the motion condition of the shifting fork is deduced, whether shifting is successful or not is judged through redundancy, and a displacement sensor is additionally arranged on each shifting fork shaft, so that the control system CAN monitor the actual movement amount of the shifting fork when the motor is locked, and the real state of the shifting process is obtained.

Drawings

FIG. 1 is a schematic structural diagram of a device used in a parameter-variable gear-shifting process of an AMT transmission.

FIG. 2 is a flow chart of the method for controlling the parameter-variable gear-shifting process of the AMT.

Fig. 3 is a schematic diagram of a control strategy for the rotating speed of the motor according to the present invention.

Detailed Description

The present invention is described in further detail below in order to enable those skilled in the art to practice the invention with reference to the description.

The invention provides a method for controlling a parameter-variable gear shifting process of an AMT (automated mechanical transmission), which comprises the following steps of firstly changing on the basis of a traditional mechanical manual transmission, reserving a plurality of shifting fork shafts with multiple gears, as shown in figure 1, in the embodiment, the method is a four-gear transmission controlled by a double motor, and specifically comprises the following steps: the device comprises a first motor 130a, a second motor 130b, a detection unit, a transmission electronic control unit 110 and a CAN bus, wherein the first motor 130a and the second motor 130b are respectively connected with two shifting fork shafts in a one-to-one correspondence manner and CAN control the two shifting fork shafts in a one-to-one correspondence manner; in this embodiment, the first motor 130a and the second motor 130b are both stepping motors; the detection unit is arranged on the transmission and used for determining the state parameters of the transmission, so that the closed-loop control of the gear shifting process is realized, and the gear shifting quality is improved; the transmission electronic control unit 110 is connected with the first motor 130a, the second motor 130b, the detection unit and the vehicle display instrument 150, and is used for controlling the motors so as to drive the shifting fork shaft to move and complete automatic gear shifting; the CAN bus is arranged among the gear shift handle 140, the first motor 130a, the second motor 130b, the detection unit, the transmission electronic control unit 110 and the vehicle display instrument 150, and is used for collecting signals and transmission signals of the gear shift handle 140, controlling the first motor 130a and the second motor 130b to operate through the first CAN communication interface 113, and simultaneously collecting gear shift signals of the gear shift handle 140 and transmitting gear shift gears to the vehicle display instrument 150 through the second CAN communication interface 114.

The detection unit specifically includes: a first rotational speed sensor 121, a second rotational speed sensor 122, a first displacement sensor 124, a second displacement sensor 125, a first current sensor 123a and a second current sensor 123b, wherein the first rotational speed sensor 121 is provided on an input shaft of the transmission for detecting a rotational speed of the input shaft of the transmission; a second rotational speed sensor 122 provided on the output shaft of the transmission for detecting the rotational speed of the output shaft of the transmission; the first rotation speed sensor 121 and the second rotation speed sensor 122 are connected with the transmission electronic control unit 110 through a capture comparison interface 111; a first current sensor 123a is provided in a control circuit of the first motor 130a, and a second current sensor 123b is provided in a control circuit of the second motor 130b, for detecting load currents of the first motor 130a and the second motor 130 b; the displacement sensors are respectively arranged on the shifting fork shafts in a one-to-one correspondence manner and are used for detecting the displacement of the shifting fork shafts, namely the movement distance of the shifting forks; milling a plane on the side surface of a rocker arm of an output shaft of a gear shifting motor, and arranging a displacement sensor to be opposite to the plane when the rocker arm is in a neutral position; during gear shifting, the motor drives the rocker arm to rotate, the output signal of the displacement sensor changes along with the different distances from the motor to the rocker arm, and the calibration of the displacement sensor in the gear shifting process can be realized by acquiring the whole gear shifting stroke data. The first displacement sensor 124, the second displacement sensor 125, the first current sensor 123a, and the second current sensor 123b are connected to the transmission electronic control unit 110 via the AD conversion interface 112.

According to the method for controlling the parameter-variable gear shifting process of the AMT, the load moment is increased in the synchronizing process stage of the transmission with the synchronizer, and the load moment is reduced after the synchronizing process is finished. And the change of load moment can lead to the change of motor armature current value, for this reason, adopt the current sensor to detect and control the motor armature current, judge the stage of shifting through the change of current, as shown in fig. 2, include the following step specifically:

step one, collecting a signal of a gear shifting handle of a driver, judging a gear to be hooked, and determining a gear shifting fork shaft to be operated according to a target gear;

step two, keeping the non-target shifting fork shaft in a neutral gear:

the interlocking of the transmission is to ensure that only one gear can be hooked at a time, so that before gear shifting, other shifting fork shafts except for a target gear shifting fork shaft are required to be ensured to be in a neutral position, interlocking judgment is required to be carried out firstly, the gear of the non-target gear shifting fork shaft is judged through data of a displacement sensor, and if the gear is not in the neutral position, the gear is controlled to return to the neutral position.

Step three, driving a target shifting fork shaft to complete gear shifting through a motor:

and after the position of each gear shifting fork shaft is judged to meet the interlocking condition, gear shifting control is started. The key problem of the gear shifting execution control strategy is gear shifting speed control, in the gear shifting process, a shifting fork rod drives a shifting fork to move, the motion stroke can be divided into three stages, the shifting fork in the 1 st stage drives a combination sleeve to move from a neutral position until the combination sleeve is contacted with a lock ring of a gear ring to be combined, the contact conical surface of the combination sleeve and the lock ring in the second stage generates sliding grinding motion, namely the synchronization process of a synchronizer, and the third stage is the process that the combination sleeve passes over the lock ring and is completely meshed with the gear ring to be combined after synchronization is completed. The resistance moments in the first stage and the third stage are small, and the movement speed of the shifting fork shaft can be improved as much as possible during control. In the second stage, namely the synchronization process stage, because of the existence of friction torque, the load torque of the stepping motor is increased, the movement speed of the shifting fork shaft needs to be reduced, and enough synchronization time is ensured to enable the rotating speeds of the driving part and the driven part of the transmission to be consistent. In the gear shifting process, the load current and the change rate of the speed difference between the driving part and the driven part can indirectly feed back the friction torque, the control quantity of the rotating speed of the motor is determined by utilizing a feedback signal, meanwhile, the feedback signal obtained by the test is considered to be easy to be fused into an interference signal, and the speed of the motor is controlled by adopting a module controller:

as shown in fig. 3, the fuzzy control strategy for the target rotation speed of the motor includes the following steps:

step 1, fuzzy subsets and fuzzy membership functions of input signals and output control signals are selected:

respectively converting the load current, the difference between the main rotating speed and the auxiliary rotating speed and the rotating speed of the motor into quantization levels in a fuzzy theory domain;

and inputting the load current and the main-auxiliary rotating speed difference as input signals into a fuzzy controller, wherein the load current in the fuzzy controller is divided into 3 grades, the main-auxiliary rotating speed difference is divided into 5 grades, the fuzzy controller outputs the motor rotating speed, and the motor rotating speed is divided into 3 grades.

The argument range of the load current is [0, 2000], the argument range of the main-driven rotating speed difference is [ -2500, 2500], and the argument range of the motor rotating speed is [0, 200 ].

The fuzzy set of the load current is { S, M, B }, the fuzzy set of the driving and driven rotating speed differences is { NB, NS, ZO, PS, PB }, and the fuzzy set of the motor rotating speed is { S, M, B }.

The membership function of the input signal adopts a Gaussian membership function, and the calculation formula is as follows:

the membership function of the output signal adopts a triangular membership function, and the calculation formula is as follows:

step 2, fuzzy inference rules:

according to the experience, the fuzzy value range of the input signal and the output control signal, a motor rotating speed fuzzy inference rule is formulated,

the control rule of the fuzzy controller is as follows:

Specifically, the results are shown in Table 1.

TABLE 1 fuzzy inference rule table for motor speed

Step four, judging whether the gear shifting is in place or not by adopting a redundancy judgment mode:

under a certain gear shifting stroke, the control pulse number of the motor is a determined value; after gear shifting is finished, the rotating speed difference of the driving part and the driven part of the transmission is 0, and the rotating speed ratio of the input shaft and the output shaft of the transmission is the transmission ratio of the hitching gear; when the gear shifting is completed, the value of the load current sensor is remarkably reduced, and in addition, the test value of the shift fork position displacement sensor can also judge whether the gear shifting is in place. Because the sensor has errors and is possible to have faults in the using process, redundancy judgment is adopted when the gear shifting in-place judgment is carried out, and whether the displacement sensor drifts or fails is judged according to redundancy information. The decision logic is shown in table 2.

TABLE 2 Shift in-place and sensor Fault determination logic

The coincidence of the control pulse number of the motor means that the control pulse number is consistent with the pulse number required by the gear shifting stroke, and the inconsistency is not consistent if the control pulse number is not consistent with the pulse number required by the gear shifting stroke; the shift fork displacement coincidence means that the distance from the shift fork position to the displacement sensor is +/-0.1 mm, and if the shift fork displacement coincidence is not coincident, the distance measured by the sensor deviates from the gear distance value and is out of an allowable error; the main driven rotation speed ratio of the transmission is consistent, namely the rotation speed ratio is consistent with the gear transmission ratio, and if the rotation speed ratio is not consistent with the gear transmission ratio, the rotation speed ratio is inconsistent; the load current value is in accordance with the control current value when the sensor output value and the transmission are in the hanging gear, the error is smaller than 1A, and the non-compliance means that the sensor output value and the control current value when the transmission is in the hanging gear are inconsistent and are out of the allowable error.

As shown in table 2, it is determined whether or not a shift is in place based on 4 pieces of sensing information, and when only 1 of the 4 pieces of sensing information does not match, it is determined that the information that does not match is failure information.

The method for controlling the parameter-variable gear shifting process of the AMT transmission realizes the gear shifting rhythm of 'fast-slow-fast'. The clearance of the friction pair is eliminated quickly, so that the gear shifting time is saved; the shifting fork moving speed is slow in the friction synchronization process, enough friction torque is kept, abrasion of a synchronizer caused by overlarge friction torque is avoided, and the problem of long shifting time caused by insufficient friction force can be solved; the hooking action of the synchronized meshing sleeve is also fast; according to the electric load characteristics of the motor, the gear shifting action process of the motor is known by monitoring the load current of the motor, the time when the synchronous conical rings start to rub and finish synchronously is automatically analyzed, and a control strategy can be modified by a control system; automatically selecting control parameters according to the position of the stage dividing point and the state parameters of the system by adopting a fuzzy control theory; rotation information (rotation angle and rotation speed control target, driving current limitation and whether the motor is locked or not) of the motor is fed back through the CAN bus, so that the motion condition of the shifting fork is deduced, a displacement sensor is additionally arranged on each shifting fork shaft, and the control system CAN monitor the actual movement amount of the shifting fork when the motor is locked.

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 to various fields of endeavor for which the invention may be embodied with additional modifications as would be readily apparent to those skilled in the art, and the invention is therefore not limited to the details given herein and to the embodiments shown and described without departing from the generic concept as defined by the claims and their equivalents.

Claims

1. A method for controlling a parameter-variable gear shifting process of an AMT transmission is characterized by comprising the following steps:

step two, the non-target shifting fork shaft is kept in a neutral gear;

the membership function of the input signal of the fuzzy controller adopts a Gaussian membership function, and the calculation formula is as follows:

the membership function of the output signal of the fuzzy controller adopts a triangular membership function, and the calculation formula is as follows:

2. The AMT transmission variable parameter shift process control method according to claim 1, further comprising:

3. The AMT transmission variable parameter gear shifting process control method according to claim 2, wherein the detecting unit includes:

4. The AMT transmission variable parameter gear shifting process control method according to claim 3, wherein the argument of the load current is [0, 2000], the argument of the main-driven rotation speed difference is [ -2500, 2500], and the argument of the motor rotation speed is [0, 200 ].

5. The AMT transmission variable parameter shift process control method according to claim 4, wherein the fuzzy set of load currents is { S, M, B }, the fuzzy set of primary and secondary rotational speed differences is { NB, NS, ZO, PS, PB }, and the fuzzy set of motor rotational speeds is { S, M, B }.

6. The AMT transmission variable parameter gear shifting process control method according to claim 5, wherein the control rule of the fuzzy controller is:

7. The method for controlling the parameter-changing gear-shifting process of the AMT transmission according to claim 6, wherein in the fourth step, the redundancy judgment is carried out through the values of the motor control pulse number, the shift fork displacement, the transmission master-slave speed ratio and the load current:

8. The method according to claim 7 wherein said first stage in step two is a process in which a shift fork drives a coupling sleeve from a neutral position to contact a lock ring of a gear ring to be coupled;

the second stage is a synchronization process of the synchronizer;