A speed-difference-based torque zero-crossing tooth surface fitting method, device and equipment

Abstract

The application provides a speed difference-based torque zero-crossing gear face fitting method, device and equipment, relates to the vehicle control technical field, and the application calculates the expected motor speed of each electric angle during the first tooth side gap process after the motor torque commutation. The expected motor speed is determined according to the wheel end speed corresponding to the electric angle and the target speed difference. The target speed difference corresponding to the electric angle of the first tooth side gap front section area is greater than the target speed difference corresponding to the electric angle of the last section area. The expected motor speed is determined based on the target speed difference and the wheel end speed preset according to the current electric angle. The expected motor speed change rate of the electric angle is determined according to the expected motor speed and the actual motor speed, and the error between the actual motor speed change rate and the expected motor speed change rate is subjected to PID control, and the control error converges to zero. In this way, the torque zero-crossing time can be shortened and the impact can be reduced, so as to improve the continuity and smoothness of vehicle power output.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, and in particular to a method, apparatus and equipment for torque zero-crossing tooth surface contact based on speed difference. Background Technology

[0002] Except for new energy vehicles equipped with in-wheel motors, the power from the motor to the wheels must be transmitted through a transmission mechanism including a reducer. See also Figure 1 The diagram shows a gear meshing structure. When switching between D / R gears under the action of releasing and pressing the accelerator and creeping torque, the direction of the vehicle's output torque changes, and the driving force F... 驱动 The direction also changes accordingly. After the torque in the original torque direction decays to 0, the reverse torque is gradually increased, which is called torque zero crossing. During this process, in the transmission mechanism, the contact tooth surfaces between the driving gear driven by the drive motor and the driven gear at the connecting wheel end will change direction. The driving teeth of the driving gear will disengage from the original contact tooth surface of the driven gear and then engage with another tooth surface after passing through the tooth flank clearance.

[0003] Torque crossing to zero occurs frequently in daily driving. If not controlled properly, it can lead to problems such as power interruption and strong jolts, affecting the driving experience. Summary of the Invention

[0004] In view of this, embodiments of this application provide a method, apparatus and equipment for zero-torque tooth surface contact based on speed difference, which aims to avoid the problem of strong power interruption and impact during the process of torque crossing to zero.

[0005] In a first aspect, embodiments of this application provide a torque zero-crossing tooth surface fitting method based on speed difference, the method comprising:

[0006] In response to switching between forward and reverse gears or releasing the accelerator pedal, the original torque of the motor is reduced to zero.

[0007] After the motor torque is reversed, the expected motor speed is calculated for each electrical angle during the process of passing through the first tooth side clearance. The expected motor speed is determined based on the wheel end speed corresponding to the electrical angle and the target speed difference. The target speed difference is preset based on the region of the first tooth side clearance corresponding to the electrical angle, and the target speed difference corresponding to the electrical angle in the first section of the first tooth side clearance is greater than the target speed difference corresponding to the electrical angle in the last section.

[0008] Based on the desired motor speed and the actual motor speed corresponding to the electrical angle, determine the desired motor speed change rate of the electrical angle;

[0009] The error between the actual motor speed change rate corresponding to the electrical angle and the desired motor speed change rate is controlled by PID control to bring the error toward zero.

[0010] After passing through the first tooth side clearance, the motor torque is controlled to return to the target torque.

[0011] Optionally, the calculation of the desired motor speed at each electrical angle during the first tooth backlash includes:

[0012] The electrical angle is obtained by subtracting and integrating the rotational speed of the driving gear on the motor side and the rotational speed of the driven gear on the wheel side.

[0013] Obtain the corresponding wheel end speed at the electrical angle;

[0014] The desired motor speed is obtained by summing the wheel end speed and the target speed difference, based on the electrical angle.

[0015] Optionally, the preset method for the target speed difference is as follows:

[0016] Based on the different regions traversed by the first tooth flank clearance, a target speed difference corresponding to the electrical angle of each region is preset; the electrical angle corresponding to the first tooth flank clearance of the same vehicle is fixed.

[0017] Optionally, determining the rate of change of the desired motor speed for the electrical angle based on the desired motor speed and the actual motor speed corresponding to the electrical angle includes:

[0018] Calculate the speed difference between the desired motor speed and the actual motor speed corresponding to the electrical angle;

[0019] The expected rate of change of motor speed corresponding to the electrical angle is determined by looking up a table.

[0020] Optionally, the feedforward term of the PID control is the desired angular acceleration multiplied by the moment of inertia of the drive unit, the drive unit including a motor, or the drive unit including a motor and a gear with driving force linked at the corresponding electrical angle, the desired angular acceleration being determined based on the desired rate of change of rotational speed;

[0021] The P-term coefficient of the PID control is determined by looking up the P-term coefficient table based on the motor torque corresponding to the electrical angle and the actual motor speed at the electrical angle.

[0022] The I-coefficient of the PID control is determined by looking up the I-coefficient table based on the motor torque corresponding to the electrical angle and the actual motor speed at the electrical angle.

[0023] The D-term coefficient of the PID control is determined by referring to the D-term coefficient table based on the cumulative error corresponding to the electrical angle and the actual motor speed at the electrical angle.

[0024] Optionally, the first tooth flank clearance is the sum of the tooth flank clearances of all two adjacent gears between the motor-side driving gear and the wheel-side driven gear.

[0025] Optionally, the first tooth flank clearance is one of the tooth flank clearances of all two adjacent gears between the driving gear on the motor side and the driven gear on the wheel end.

[0026] or,

[0027] The first tooth flank clearance is the sum of the tooth flank clearances of all two adjacent gears included between the motor-side driving gear and the first driven gear, and the first driven gear is one of the driven gears included between the motor-side driving gear and the wheel-end driven gear.

[0028] Optionally, controlling the motor torque to restore it to the target torque includes:

[0029] The motor torque is controlled to achieve the engagement of all non-engaged gears from the driving gear on the motor side to the driven gear on the wheel end with a first slope rate of change of motor torque over time;

[0030] The motor torque is controlled to recover to the target torque at a rate of change of motor torque over time with a second slope, wherein the absolute value of the first slope is less than the absolute value of the second slope, and the target torque is determined based on the driver's control state of the throttle.

[0031] Secondly, this application provides a torque zero-crossing tooth surface contact device based on speed difference, the device comprising:

[0032] The first control module is used to control the motor torque to decrease to zero in response to switching between forward and reverse gears or releasing the accelerator pedal.

[0033] The calculation module is used to calculate the expected motor speed at each electrical angle during the process of passing through the first tooth side clearance after the motor torque commutation. The expected motor speed is determined based on the wheel end speed corresponding to the electrical angle and the target speed difference. The target speed difference is preset based on the region of the first tooth side clearance corresponding to the electrical angle.

[0034] The determining module is used to determine the rate of change of the expected motor speed for the electrical angle based on the expected motor speed and the actual motor speed corresponding to the electrical angle.

[0035] The second control module is used to perform PID control on the error between the actual motor speed change rate corresponding to the electrical angle and the desired motor speed change rate, and to control the error to converge to zero.

[0036] The third control module is used to control the motor torque to return to the target torque after passing through the first tooth side clearance.

[0037] Thirdly, this application provides a motor control device, including a memory and a processor, wherein the memory is used to store instructions or code, and the processor is used to execute the instructions or code to cause the device to perform the above-described torque zero-crossing tooth surface contact method based on speed difference.

[0038] This application provides a method, apparatus, and device for torque zero-crossing tooth surface bonding based on speed difference. First, in response to switching between forward and reverse gears or releasing the accelerator, the original torque of the motor is controlled to decay to zero. When torque zero-crossing occurs, the current original torque is rapidly decayed to zero, shortening the time to zero torque. Then, after the motor torque is reversed, the desired motor speed for each electrical angle during the passage through the first tooth side clearance is calculated. The desired motor speed is determined based on the wheel end speed corresponding to the electrical angle and the target speed difference, and the target speed difference corresponding to the electrical angle in the first section of the first tooth side clearance is greater than the target speed difference corresponding to the electrical angle in the last section. The electrical angle corresponding to the first tooth side clearance of the same vehicle is fixed, and the current region or position within the first tooth side clearance is determined based on the electrical angle. The desired motor speed is determined based on the preset target speed difference and wheel end speed of the current electrical angle. Since the target speed difference corresponding to the electrical angle in the first section is greater than the target speed difference corresponding to the electrical angle in the last section, rapid disengagement from the original bonding tooth surface is achieved, and bonding is completed in the last section with a lower target speed difference. Finally, based on the desired motor speed and the current actual motor speed, the desired motor speed change rate of the electrical angle is determined, and the error between the current actual motor speed change rate and the desired motor speed change rate is controlled by PID to bring the error toward zero. In this way, based on the target speed difference, it is possible to quickly disengage from the original contact tooth surface during the process of passing through the tooth flank clearance, and then reduce the contact time between the driving gear and the other tooth surface, and the speed difference between the driving tooth surface and the driven tooth surface, so as to achieve the effect of static meshing as much as possible. This can take into account the shortening of the torque zero crossing time and the reduction of impact, thereby improving the continuity and smoothness of vehicle power output. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in this embodiment or the prior art, the drawings used in the description of the embodiment or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 A schematic diagram of a gear meshing structure is provided for the background art of this application;

[0041] Figure 2 This is a schematic diagram of a torque zero-crossing control process provided in an embodiment of this application;

[0042] Figure 3 A flowchart illustrating a torque zero-crossing tooth surface fitting method based on speed difference, provided for embodiments of this application;

[0043] Figure 4 A schematic diagram of the control process of a torque zero-crossing tooth surface contact method based on speed difference provided in an embodiment of this application;

[0044] Figure 5 This is a schematic diagram of a torque zero-crossing tooth surface bonding device based on speed difference, provided in an embodiment of this application. Detailed Implementation

[0045] See Figure 1 In the middle, there are three states when the torque crosses zero, such as Figure 1 (a) represents the state before the torque crosses zero, where the motor torque gradually decreases from its original value to zero. Figure 1 (b) represents the state during torque zero crossing. After the motor torque reverses, the driving gear disengages from the original tooth surface of the driven gear and engages with the other tooth surface through the tooth flank clearance, such as... Figure 1 (c) represents the state after the torque crosses zero. The other tooth surfaces of the driving gear and the driven gear are in contact, and the torque continues to increase to the torque required by the driver. The moment of transition between the state during and after the torque crosses zero is the point of collision between the driving gear and the driven gear on the other tooth surface.

[0046] Therefore, see Figure 2 The diagram illustrates a torque zero-crossing control process. Regardless of whether the torque changes from negative to positive or vice versa, the goal is to achieve a slow transition during the commutation process, minimizing commutation impact. This reduces the rate of change of motor torque over time. (See [reference]). Figure 2 (a) However, the slope is still relatively large, and the facet change impact still exists. For further optimization, see [link to optimization]. Figure 2 (b) A reverse small torque platform is formed within the zero-crossing range of the gear shaft face change, achieving the purpose of sliding and contacting the surface during gear shaft face change, greatly reducing the face change impact. However, due to the different clearances and stresses between shaft systems, the speed of the gear shaft at the zero-crossing moment varies due to factors such as vehicle deformation during torque withdrawal. The face change impact point itself has different operating conditions, resulting in generally poor robustness of the zero-crossing open-loop control. Therefore, a gear surface face change method based on target speed difference closed-loop control is further proposed, see [reference]. Figure 2 (c) The actual motor torque is controlled based on the target speed difference. During the process of passing through the tooth flank gap, it is possible to quickly disengage from the original tooth surface. Then, it is necessary to reduce the contact time between the driving gear and the other tooth surface, and the speed difference between the driving tooth surface and the driven tooth surface, so as to achieve the effect of static meshing as much as possible. This can take into account both the reduction of zero crossing time and the reduction of impact.

[0047] Specifically, this application proposes a torque zero-crossing tooth surface contact method based on speed difference. First, in response to switching between forward and reverse gears or releasing the accelerator, the original torque of the motor is controlled to decay to zero. When torque zero-crossing occurs, the current original torque is rapidly decayed to zero, shortening the time to zero torque. Then, after the motor torque is reversed, the desired motor speed for each electrical angle during the passage through the first tooth side clearance is calculated. The desired motor speed is determined based on the wheel end speed corresponding to the electrical angle and the target speed difference. The target speed difference is preset based on the region of the first tooth side clearance corresponding to the electrical angle, and the target speed difference corresponding to the electrical angle in the first part of the first tooth side clearance is greater than that in the last part. The electrical angle corresponding to the first tooth side clearance of the same vehicle is fixed. Based on the electrical angle, the current region or position within the first tooth side clearance is determined, and then the desired motor speed is determined based on the preset target speed difference and wheel end speed of the current electrical angle. The target speed difference corresponding to the electrical angle in the first region is greater than that in the last region, which is used to achieve rapid disengagement from the original meshing tooth surface, and to complete meshing in the last region with a lower target speed difference. Finally, based on the desired motor speed and the current actual motor speed, the desired motor speed change rate of the electrical angle is determined, and the error between the current actual motor speed change rate and the desired motor speed change rate is controlled by PID control to bring the error towards zero. In this way, based on the target speed difference, it is possible to quickly disengage from the original meshing tooth surface during the process of passing through the tooth flank clearance, and then reduce the speed difference between the driving gear and the driven tooth surface at the moment of meshing with the other tooth surface, so as to achieve the effect of static meshing as much as possible, which can take into account both the shortening of the torque zero crossing time and the reduction of impact.

[0048] Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0049] Figure 3 A flowchart of a torque zero-crossing tooth surface fitting method based on speed difference provided in this application embodiment is shown below. Figure 3 A torque zero-crossing tooth surface fitting method based on speed difference, comprising:

[0050] S301, in response to switching between forward and reverse gears or releasing the accelerator pedal, controls the original torque of the motor to decrease to zero.

[0051] In one possible implementation, the forward gear is R and the reverse gear is D. When shifting from forward to reverse or vice versa, the original torque can be controlled to decay to 0 at a large slope (the rate of change of torque over time), shortening the time consumed for the torque to cross zero and improving the user's driving experience.

[0052] S302. After the motor torque is reversed, the expected motor speed at each electrical angle during the process of passing through the first tooth side clearance is calculated. The expected motor speed is determined based on the wheel end speed corresponding to the electrical angle and the target speed difference. The target speed difference is preset based on the region of the first tooth side clearance corresponding to the electrical angle, and the target speed difference corresponding to the electrical angle in the first section of the first tooth side clearance is greater than the target speed difference corresponding to the electrical angle in the last section.

[0053] The motor torque is transmitted through gears, ultimately driving the wheel to rotate. Among all the transmission gears between the driving gear at the motor end and the driven gear at the wheel end, there will be tooth flank clearance between any two adjacent transmission gears to prevent the gear transmission from jamming. However, during the torque reversal process when the torque crosses zero (switching from the original torque to the reverse torque in the opposite direction of the original torque), the driving gear will disengage from the original tooth surface of the corresponding driven gear and, based on the reverse torque, engage with another tooth surface through the tooth flank clearance.

[0054] Therefore, the first tooth flank clearance is determined based on the tooth flank clearance between the gears included between the driving gear on the motor side and the driven gear on the wheel end.

[0055] For the same vehicle, since the mechanical structure and tooth backlash are fixed, and the electrical angle is determined based on the integral of the speed difference between the driving gear and the driven gear over time, the electrical angle is also fixed when the tooth backlash is fixed. Therefore, when the torque crosses zero and the driving gear meshes with the corresponding driven gear after passing through the first tooth backlash, the area or position traversing the first tooth backlash can be determined based on the electrical angle. Furthermore, based on the target speed difference in different areas of the corresponding first tooth backlash, the target speed difference is added to the wheel end speed at the corresponding electrical angle to determine the desired motor speed.

[0056] S303. Based on the desired motor speed and the actual motor speed corresponding to the electrical angle, determine the desired motor speed change rate of the electrical angle.

[0057] Under the same electrical angle, the desired rate of change of motor speed is determined by combining the desired motor speed and the actual motor speed. Subsequent adjustments are then made by taking into account the actual operating conditions in conjunction with the actual motor speed.

[0058] S304. Perform PID control on the error between the actual motor speed change rate corresponding to the electrical angle and the desired motor speed change rate, and control the error to converge to zero.

[0059] By using PID control to measure the error between the actual motor speed change rate and the desired motor speed change rate under the same electrical angle, more precise motor control can be achieved.

[0060] S305. After passing through the first tooth side clearance, control the motor torque to recover to the target torque.

[0061] Since the electrical angle corresponding to the first tooth side gap is fixed, the fitting of the first tooth side gap is completed according to the electrical angle, and the first tooth side gap is passed through.

[0062] In one possible implementation, after the gears mesh through the first tooth clearance, the reverse torque can recover to the target torque with a larger slope (the rate of change of torque over time). The larger slope reduces the time consumed to bring the torque to zero, thus improving the user's driving experience.

[0063] As can be seen from steps S301-S305 above, this application uses a larger slope to control the motor torque before the torque reaches zero in step S301 and in step S305, reducing the time consumed for the torque to reach zero. In step S302, based on the first tooth flank clearance, a target speed difference corresponding to the electrical angle of different regions of the first tooth flank clearance is preset. Subsequently, based on the target speed difference and the wheel end speed, the desired motor speed is determined, and based on the desired motor speed and the actual motor speed, the final desired motor speed change rate is determined considering the actual working conditions. Finally, PID control is applied to the error between the actual motor speed change rate and the desired motor speed change rate under the same electrical angle to achieve more precise motor control. In this way, based on the fact that the target speed difference corresponding to the electrical angle of the first region of the first tooth flank clearance is greater than the target speed difference corresponding to the electrical angle of the last region, it is possible to quickly disengage from the original contact tooth surface during the process of passing through the first tooth flank clearance, and then reduce the moment of impact contact with the other tooth surface. The speed difference between the active tooth surface and the driven tooth surface is minimized to achieve the effect of static meshing as much as possible, which can balance the reduction of torque zero-crossing time and the reduction of impact.

[0064] In the embodiments of this application, the above Figure 3 There are possible implementations of step S302, which will be described below. It should be noted that the implementations given below are only illustrative examples and do not represent all implementations of the embodiments of this application.

[0065] In one possible implementation, the desired motor speed at each electrical angle during the first tooth backlash is calculated, specifically as follows:

[0066] The electrical angle is obtained by subtracting and integrating the rotational speed of the driving gear on the motor side and the rotational speed of the driven gear on the wheel side.

[0067] Specifically, the electrical angle = ∫(rotational speed of the driving gear on the motor side - rotational speed of the driven gear on the wheel side) dt.

[0068] Obtain the corresponding wheel end speed at the electrical angle.

[0069] Specifically, the wheel-end rotation speed is equal to the vehicle speed divided by the tire circumference.

[0070] The desired motor speed is obtained by summing the wheel end speed and the target speed difference, based on the electrical angle.

[0071] The desired motor speed is determined based on the wheel end speed and the target speed difference, thereby enabling motor adjustment based on the target speed difference.

[0072] Furthermore, in the above embodiments, the method for presetting the target speed difference can specifically be:

[0073] Based on the different regions traversed by the first tooth flank clearance, a target speed difference corresponding to the electrical angle of each region is preset; the electrical angle corresponding to the first tooth flank clearance of the same vehicle is fixed.

[0074] For example, during the process of the active gear on the active side completing gear meshing through the first tooth side clearance, the specific area that can pass through the first tooth side clearance may include a first area and a second area.

[0075] Specifically, the target speed difference corresponding to the electrical angle in the first region is greater than the target speed difference corresponding to the electrical angle in the second region, and the target speed difference corresponding to the electrical angle in the second region does not exceed 10 rpm. For example, the target speed difference corresponding to the electrical angle in the first region can be 20 rpm, and the target speed difference corresponding to the electrical angle in the second region can be 5 rpm.

[0076] Specifically, the area of ​​the first region is larger than that of the second region. For example, the area of ​​the first region can occupy two-thirds of the entire first tooth flank clearance, while the area of ​​the second region can occupy one-third of the entire first tooth flank clearance.

[0077] In the embodiments of this application, the above Figure 3 There are possible implementations of step S303, which will be described below. It should be noted that the implementations given below are merely illustrative examples and do not represent all implementations of the embodiments of this application.

[0078] In one possible implementation, the rate of change of the desired motor speed at the electrical angle is determined based on the desired motor speed and the actual motor speed corresponding to the electrical angle. Specifically, this can be achieved by:

[0079] Calculate the speed difference between the desired motor speed and the actual motor speed corresponding to the electrical angle.

[0080] Specifically, the speed difference = desired motor speed - actual motor speed.

[0081] The expected rate of change of motor speed corresponding to the electrical angle is determined by looking up a table.

[0082] In one possible implementation, the lookup table is based on the expected rate of change of motor speed determined through experimental experience based on the speed difference.

[0083] In the embodiments of this application, the above Figure 3 The first tooth flank clearance in step S302 can be implemented in various ways, which will be described below. It should be noted that the implementation methods given below are only illustrative examples and do not represent all implementation methods of the embodiments of this application.

[0084] In a first possible implementation, the first tooth flank clearance is one of the tooth flank clearances of all two adjacent gears included between the motor-side driving gear and the wheel-side driven gear.

[0085] Specifically, the tooth flank clearance of one of the tooth flank clearances of all adjacent gears between the motor-side driving gear and the wheel-side driven gear is used as the first tooth flank clearance to approximate the tooth flank clearance between the motor-side driving gear and the wheel-side driven gear. In this way, the control scheme can be simplified and the amount of calculation can be reduced by approximating the tooth flank clearance using a single tooth flank clearance.

[0086] For example, the first tooth flank clearance can be the maximum tooth flank clearance among all the tooth flank clearances of two adjacent gears included from the motor-side driving gear to the wheel-side driven gear. That is, the maximum tooth flank clearance is used as the first tooth flank clearance, which is approximately the tooth flank clearance between the motor-side driving gear and the wheel-side driven gear.

[0087] In a second possible implementation, the first tooth flank clearance is the sum of the tooth flank clearances of all two adjacent gears between the motor-side driving gear and the wheel-side driven gear.

[0088] Specifically, the sum of the tooth flank clearances of all adjacent gears between the motor-side driving gear and the wheel-side driven gear is used as the first tooth flank clearance. This ensures that after passing through the first tooth flank clearance, all gears between the motor-side driving gear and the wheel-side driven gear can achieve torque zero crossing and then engage based on the reverse torque.

[0089] For example, a transmission structure is defined, in which the gears from the motor end to the wheel end of the transmission structure include a first gear, a second gear, a third gear and a fourth gear in sequence. The tooth flank clearance between the first gear and the second gear, the tooth flank clearance between the second gear and the third gear and the tooth flank clearance between the third gear and the fourth gear are calculated as the first tooth flank clearance of the transmission structure.

[0090] In a third possible implementation, the first tooth flank clearance is the sum of the tooth flank clearances of all two adjacent gears included between the motor-side driving gear and the first driven gear, and the first driven gear is one of the driven gears included between the motor-side driving gear and the wheel-end driven gear.

[0091] For example, the first driven gear can be the driven gear corresponding to the maximum tooth backlash between the driving gear on the motor side and the driven gear on the wheel end. This reduces the amount of calculation while also ensuring that the gear with the maximum tooth backlash is engaged at a low speed as much as possible.

[0092] For example, based on the above-described transmission structure, if the tooth flank clearance between the second gear and the third gear is set to be the largest tooth flank clearance in the transmission structure, then the sum of the tooth flank clearance between the first gear and the second gear and the tooth flank clearance between the second gear and the third gear is taken as the first tooth flank clearance of the transmission structure.

[0093] Furthermore, based on the first and third possible implementations mentioned above, when partial gear engagement is achieved, if there are still unengaged gears after passing through the first tooth flank clearance, it is possible to... Figure 3 Step S305 further supplements the control. Specifically, for controlling the motor torque to recover to the target torque, the specific steps may include:

[0094] Step S3051: Control the motor torque to complete the engagement of all unengaged gears from the motor end driving gear to the wheel end driven gear with the motor torque changing with time at a first slope.

[0095] For example, the time for setting the motor torque to control torque variation at a first slope can be determined experimentally or empirically. This time is greater than or equal to the time required to complete the engagement of all non-engaged gears from the driving gear at the motor end to the driven gear at the wheel end at the first slope. The slope of the first slope is adjusted to ensure that engagement of non-engaged gears can also be achieved with a lower speed difference.

[0096] Step S3052: Control the motor torque to recover to the target torque with the rate of change of motor torque over time at the second slope, where the absolute value of the first slope is less than the absolute value of the second slope, and the target torque is determined based on the driver's control state of the throttle.

[0097] For example, the second slope can correspond to the slope setting of torque attenuation in step S301, so that the target torque can be reached at a faster speed after the bonding is completed.

[0098] For example, the target torque is determined based on the driver's control of the accelerator; the deeper the driver presses the accelerator, the greater the target torque.

[0099] In the embodiments of this application, the above Figure 3 The PID control in step S304 can be implemented in various ways, which will be described below. It should be noted that the implementation methods described below are merely illustrative examples and do not represent all implementation methods of the embodiments in this application.

[0100] The feedforward term of the PID control is the desired angular acceleration multiplied by the moment of inertia of the drive unit. The drive unit includes a motor, or the drive unit includes a motor and a gear with driving force that is linked at the corresponding electrical angle. The desired angular acceleration is determined according to the desired rate of change of rotational speed.

[0101] In one possible implementation, the drive unit may include a motor, and the moment of inertia of the drive unit is the moment of inertia of the motor.

[0102] For example, based on the first to the third possible implementations described above, the drive unit can be a motor, which simplifies the computation.

[0103] In another possible implementation, the drive unit may further include a motor and a gear that drives the vehicle at the current electrical angle. The rotational inertia of the drive unit can then include the rotational inertia of the motor and the rotational inertia of the gear that drives the vehicle at the current electrical angle. For example, based on the third possible implementation described above, when determining the first tooth flank clearance, the first gear closest to the motor end, corresponding to the current electrical angle, meshes with the second gear as it passes through the first tooth flank clearance. The second gear, in its backward transmission, will mesh with the third gear after passing through the corresponding tooth flank clearance. Therefore, the rotational inertia of the drive unit can be the rotational inertia of the motor generating the driving action, the rotational inertia of the first gear, and the rotational inertia of the second gear.

[0104] Angular acceleration (unit: rad / s) 2 The desired rate of change of rotational speed (in r / min / s) can be obtained by converting the units.

[0105] The P-term coefficient of the PID control is determined by referring to the P-term coefficient table based on the motor torque corresponding to the electrical angle and the actual motor speed at the electrical angle.

[0106] The I-term coefficient of the PID control is determined by referring to the I-term coefficient table based on the motor torque corresponding to the electrical angle and the actual motor speed at the electrical angle.

[0107] The D-term coefficient of the PID control is determined by referring to the D-term coefficient table based on the cumulative error corresponding to the electrical angle and the actual motor speed at the electrical angle.

[0108] The coefficient tables for the P, I, and D terms mentioned above can all be constructed based on experimental experience.

[0109] Based on the above embodiments, see Figure 4 The diagram shows a control process schematic of a torque zero-crossing tooth surface contact method based on speed difference.

[0110] In the first process, torque control is performed by executing the above step S301, which controls the motor torque to decay rapidly. After decaying to 0, the active side engages to drive the driven side to move, and the speed difference between the active side and the driven side is 0.

[0111] The second stage involves speed control, which uses PID control to achieve closed-loop speed control based on a preset target speed difference (the speed difference between the active and driven sides). In this stage, steps S302-S304 are executed. The vehicle passes through the first tooth side gap at a higher speed. When it approaches the collision point (based on the electrical angle corresponding to the completion of the first tooth side gap fitting process), the speed is reduced based on a lower target speed difference, resulting in low torque and low speed to prepare for static fitting. Finally, at the collision point position after the first tooth side gap fitting is completed, a low torque and low speed collision posture is achieved.

[0112] In the third stage, torque control is performed. When there are still unengaged gears between the driving and driven sides, step S3051 above can be executed to increase the reverse torque at a lower slope to complete the engagement of the unengaged gears. Then, step S3052 is executed to reach the target torque at a faster slope.

[0113] The above describes some specific implementations of the torque zero-crossing tooth surface contact method based on speed difference provided in this application. Based on this, this application also provides a corresponding device. The device provided in this application will be described below from the perspective of functional modularity.

[0114] See Figure 5 The diagram shows a structural schematic of a torque zero-crossing tooth surface contact device based on speed difference. The device includes:

[0115] The first control module 501 is used to control the motor torque to decrease to zero in response to switching between forward and reverse gears or releasing the accelerator pedal.

[0116] The calculation module 502 is used to calculate the expected motor speed at each electrical angle during the process of passing through the first tooth side clearance after the motor torque is reversed. The expected motor speed is determined based on the wheel end speed corresponding to the electrical angle and the target speed difference. The target speed difference is preset based on the region of the first tooth side clearance corresponding to the electrical angle.

[0117] The determining module 503 is used to determine the expected motor speed change rate of the electrical angle based on the expected motor speed and the actual motor speed corresponding to the electrical angle.

[0118] The second control module 504 is used to perform PID control on the error between the actual motor speed change rate corresponding to the electrical angle and the expected motor speed change rate, and control the error to converge to zero.

[0119] The third control module 505 is used to control the motor torque to return to the target torque after passing through the first tooth side clearance.

[0120] According to the aforementioned apparatus, this application employs a large slope to control the motor torque before the torque crosses zero in the first control module 501 and after the torque crosses zero in the third control module 505, thereby reducing the time consumed for torque to cross zero. In the calculation module 502, a target speed difference corresponding to different regions of the first tooth flank clearance is preset based on the first tooth flank clearance. Subsequently, the desired motor speed is determined based on the target speed difference and the wheel end speed. In the determination module 503, the final desired motor speed change rate is determined by considering the actual operating conditions based on the desired motor speed and the actual motor speed. In the second control module 504, PID control is applied to the error between the actual motor speed change rate and the desired motor speed change rate under the same electrical angle, achieving more precise motor control. In this way, based on the fact that the target speed difference corresponding to the electrical angle of the first tooth side clearance is greater than the target speed difference corresponding to the electrical angle of the last tooth side clearance, it is possible to quickly disengage from the original contact tooth surface during the process of passing through the first tooth side clearance, and then reduce the moment of impact contact with the other tooth surface. The speed difference between the active tooth surface and the driven tooth surface is reduced, so as to achieve the effect of static meshing as much as possible, which can take into account both the shortening of the torque zero crossing time and the reduction of impact.

[0121] In one possible implementation, the calculation module 502 is further configured to calculate and integrate the difference between the rotational speed of the driving gear on the motor side and the rotational speed of the driven gear on the wheel end to obtain the electrical angle; obtain the corresponding wheel end rotational speed at the electrical angle; and sum the wheel end rotational speed with the target speed difference to obtain the desired motor speed at the electrical angle.

[0122] Furthermore, the method for presetting the target speed difference can be to preset the target speed difference of each region corresponding to the electrical angle based on the different regions passed through the first tooth flank clearance; the electrical angle corresponding to the first tooth flank clearance of the same vehicle is fixed.

[0123] In another possible implementation, the determining module 503 is used to calculate the speed difference between the desired motor speed and the actual motor speed corresponding to the electrical angle; and to determine the rate of change of the desired motor speed corresponding to the electrical angle by looking up a table.

[0124] In another possible implementation, in the second control module 504, the feedforward term of the PID control is the desired angular acceleration multiplied by the moment of inertia of the drive unit. The drive unit includes a motor, or the drive unit includes a motor and a gear with driving force linked at the corresponding electrical angle. The desired angular acceleration is determined based on the desired rate of change of rotational speed. The P-term coefficient of the PID control is determined by looking up the P-term coefficient table using the motor torque corresponding to the electrical angle and the actual motor speed at the electrical angle. The I-term coefficient of the PID control is determined by looking up the I-term coefficient table using the motor torque corresponding to the electrical angle and the actual motor speed at the electrical angle. The D-term coefficient of the PID control is determined by looking up the D-term coefficient table using the cumulative error corresponding to the electrical angle and the actual motor speed at the electrical angle.

[0125] In another possible implementation, the first tooth flank clearance is the sum of the tooth flank clearances of all two adjacent gears included between the motor-side driving gear and the wheel-side driven gear; or, the first tooth flank clearance is one of the tooth flank clearances of all two adjacent gears included between the motor-side driving gear and the wheel-side driven gear; or, the first tooth flank clearance is the sum of the tooth flank clearances of all two adjacent gears included between the motor-side driving gear and the wheel-side driven gear, wherein the first driven gear is one of the driven gears included between the motor-side driving gear and the wheel-side driven gear.

[0126] In yet another possible implementation, the third control module 505 is used to control the motor torque to complete the engagement of all non-engaged gears from the motor-side driving gear to the wheel-side driven gear with a first slope rate of change of motor torque over time; and to control the motor torque to recover to the target torque with a second slope rate of change of motor torque over time, wherein the absolute value of the first slope is less than the absolute value of the second slope, and the target torque is determined based on the driver's control state of the throttle.

[0127] This application also provides corresponding motor control equipment and computer storage media for implementing the solutions provided in this application.

[0128] The motor control device includes a memory and a processor. The memory is used to store instructions or code, and the processor is used to execute the instructions or code to enable the device to perform a torque zero-crossing tooth surface contact method based on speed difference as described in any embodiment of this application.

[0129] The computer storage medium stores code. When the code is executed, the device running the code implements a torque zero-crossing tooth surface fitting method based on speed difference as described in any embodiment of this application.

[0130] In the embodiments of this application, the terms "first" and "second" (if they exist) are used only as name identifiers and do not represent the order of first and second.

[0131] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that all or part of the steps in the methods of the above embodiments can be implemented by means of software plus a general-purpose hardware platform. Based on this understanding, the technical solution of this application can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as a read-only memory (ROM) / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, a server, or a network communication device such as a router) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0132] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the apparatus embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0133] The above description is merely an exemplary implementation of this application and is not intended to limit the scope of protection of this application.

Claims

1. A torque zero-crossing tooth surface fitting method based on speed difference, characterized in that, The method includes: In response to switching between forward and reverse gears or releasing the accelerator pedal, the original torque of the motor is reduced to zero. After the motor torque is reversed, the expected motor speed is calculated for each electrical angle during the process of passing through the first tooth side clearance. The expected motor speed is determined based on the wheel end speed corresponding to the electrical angle and the target speed difference. The target speed difference is preset based on the region of the first tooth side clearance corresponding to the electrical angle, and the target speed difference corresponding to the electrical angle in the first section of the first tooth side clearance is greater than the target speed difference corresponding to the electrical angle in the last section. Based on the desired motor speed and the actual motor speed corresponding to the electrical angle, determine the desired motor speed change rate of the electrical angle; The error between the actual motor speed change rate corresponding to the electrical angle and the desired motor speed change rate is controlled by PID control to bring the error toward zero. After passing through the first tooth side clearance, the motor torque is controlled to return to the target torque.

2. The method according to claim 1, characterized in that, The calculation of the expected motor speed at each electrical angle during the first tooth backlash includes: The electrical angle is obtained by subtracting and integrating the rotational speed of the driving gear on the motor side and the rotational speed of the driven gear on the wheel side. Obtain the corresponding wheel end speed at the electrical angle; The desired motor speed is obtained by summing the wheel end speed and the target speed difference, based on the electrical angle.

3. The method according to claim 1, characterized in that, The method for presetting the target speed difference is as follows: Based on the different regions traversed by the first tooth flank clearance, a target speed difference corresponding to the electrical angle of each region is preset; the electrical angle corresponding to the first tooth flank clearance of the same vehicle is fixed.

4. The method according to claim 1, characterized in that, The step of determining the expected motor speed change rate of the electrical angle based on the expected motor speed and the actual motor speed corresponding to the electrical angle includes: Calculate the speed difference between the desired motor speed and the actual motor speed corresponding to the electrical angle; The expected rate of change of motor speed corresponding to the electrical angle is determined by looking up a table.

5. The method according to claim 1, characterized in that, The feedforward term of the PID control is the desired angular acceleration multiplied by the moment of inertia of the drive unit. The drive unit includes a motor, or the drive unit includes a motor and a gear with driving force that is linked at the corresponding electrical angle. The desired angular acceleration is determined according to the desired rate of change of rotational speed. The P-term coefficient of the PID control is determined by looking up the P-term coefficient table based on the motor torque corresponding to the electrical angle and the actual motor speed at the electrical angle. The I-coefficient of the PID control is determined by looking up the I-coefficient table based on the motor torque corresponding to the electrical angle and the actual motor speed at the electrical angle. The D-term coefficient of the PID control is determined by referring to the D-term coefficient table based on the cumulative error corresponding to the electrical angle and the actual motor speed at the electrical angle.

6. The method according to claim 1, characterized in that, The first tooth flank clearance is the sum of the tooth flank clearances of all two adjacent gears between the driving gear on the motor side and the driven gear on the wheel end.

7. The method according to claim 1, characterized in that, The first tooth flank clearance is one of the tooth flank clearances of all two adjacent gears between the driving gear on the motor side and the driven gear on the wheel end. or, The first tooth flank clearance is the sum of the tooth flank clearances of all two adjacent gears included between the motor-side driving gear and the first driven gear, and the first driven gear is one of the driven gears included between the motor-side driving gear and the wheel-end driven gear.

8. The method according to claim 7, characterized in that, Controlling the motor torque to restore it to the target torque includes: The motor torque is controlled to achieve the engagement of all non-engaged gears from the driving gear on the motor side to the driven gear on the wheel end with a first slope rate of change of motor torque over time; The motor torque is controlled to recover to the target torque at a rate of change of motor torque over time with a second slope, wherein the absolute value of the first slope is less than the absolute value of the second slope, and the target torque is determined based on the driver's control state of the throttle.

9. A torque zero-crossing tooth surface contact device based on speed difference, characterized in that, The device includes: The first control module is used to control the motor torque to decrease to zero in response to switching between forward and reverse gears or releasing the accelerator pedal. The calculation module is used to calculate the expected motor speed at each electrical angle during the process of passing through the first tooth side clearance after the motor torque commutation. The expected motor speed is determined based on the wheel end speed corresponding to the electrical angle and the target speed difference. The target speed difference is preset based on the region of the first tooth side clearance corresponding to the electrical angle. The determining module is used to determine the rate of change of the expected motor speed for the electrical angle based on the expected motor speed and the actual motor speed corresponding to the electrical angle. The second control module is used to perform PID control on the error between the actual motor speed change rate corresponding to the electrical angle and the desired motor speed change rate, and to control the error to converge to zero. The third control module is used to control the motor torque to return to the target torque after passing through the first tooth side clearance.

10. A motor control device, characterized in that, The device includes a memory and a processor, the memory being used to store instructions or code, and the processor being used to execute the instructions or code to cause the device to perform a torque zero-crossing tooth surface contact method based on speed difference as described in any one of claims 1-8.

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