Torque zero-crossing tooth surface fitting method, device and equipment based on speed difference

Abstract

The invention provides a torque zero-crossing tooth surface attaching method, device and equipment based on speed difference, and relates to the technical field of vehicle control. After motor torque reversing, the expected motor rotating speed of each electrical angle in the process of passing through a first gear backlash is calculated, and the expected motor rotating speed is determined according to the wheel end rotating speed corresponding to the electrical angle and the target speed difference; the target speed difference corresponding to the electrical angle passing through the front section area of the first backlash is larger than the target speed difference corresponding to the electrical angle passing through the tail section area of the first backlash. A desired motor speed is determined based on a preset target speed difference of the current electrical angle and a wheel end speed. The expected motor rotating speed change rate of the electrical angle is determined according to the combination of the expected motor rotating speed and the current actual motor rotating speed, PID control is performed on the error between the current actual motor rotating speed change rate and the expected motor rotating speed change rate, and the error is controlled to converge to zero, so that the torque zero-crossing time can be shortened, the impact can be reduced, and the torque zero-crossing time can be shortened. Therefore, the power output continuity and smoothness of the vehicle are improved.

Description

Technical Field

[0001] This application relates to the technical field of vehicle control, and particularly to a method, device and equipment for torque zero-crossing tooth surface fitting based on speed difference. Background Art

[0002] For new energy vehicles other than those equipped with in-wheel motors, the power of the motor needs to be transmitted to the wheel ends through a transmission mechanism including a speed reducer. Refer to Figure 1 the schematic structural diagram of a gear meshing shown. When switching between D / R gears under the action of releasing and stepping on the accelerator and creep torque, the direction of the vehicle output torque changes, and the direction of the driving force F 驱动 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 surface between the driving gear driven by the driving motor and the driven gear connected to the wheel end will change. The driving teeth of the driving gear will disengage from the original contact tooth surface of the driven gear, and after passing through the tooth side clearance (side clearance), they will fit with another tooth surface.

[0003] Torque zero-crossing occurs frequently in daily driving. If the control is not ideal, problems such as power interruption and strong impact will occur, affecting the driving experience. Summary of the Invention

[0004] In view of this, the embodiments of this application provide a method, device and equipment for torque zero-crossing tooth surface fitting based on speed difference, aiming to avoid problems such as power interruption and strong impact during torque zero-crossing.

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

[0006] In response to the switch between the forward gear and the reverse gear or the release and step on the accelerator, control the original torque of the motor to decay to zero;

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

[0008] Determine the expected motor speed change rate of the electrical angle according to the expected motor speed and the actual motor speed corresponding to the electrical angle;

[0009] 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;

[0010] Until after passing through the first flank clearance, control the motor torque to recover to the target torque.

[0011] Optionally, calculating the desired motor speed at each electrical angle during the process of passing through the first flank clearance includes:

[0012] Taking the difference between the speed of the driving gear on the motor side and the speed of the driven gear on the wheel end and integrating to obtain the electrical angle;

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

[0014] Adding the wheel end speed and the target speed difference to obtain the desired motor speed at the electrical angle.

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

[0016] According to different regions passing through the first flank clearance, preset the target speed difference of the electrical angle corresponding to each region; the electrical angle corresponding to the first flank clearance of the same vehicle is fixed.

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

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

[0019] Determining the desired motor speed change rate of the electrical angle corresponding to the speed difference 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 includes a motor, or, the drive unit includes a motor and a gear with driving force linked at the corresponding electrical angle, and the desired angular acceleration is determined according to the desired speed change rate;

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

[0022] The I-term coefficient of the PID control is determined by looking up the I-term coefficient table for 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 looking up the D-term coefficient table for the cumulative error corresponding to the electrical angle and the actual motor speed at the electrical angle.

[0024] Optionally, the first backlash is the sum of the backlashes between all adjacent two gears from the driving gear on the motor side to the driven gear at the wheel end.

[0025] Optionally, the first backlash is one of the backlashes between all adjacent two gears from the driving gear on the motor side to the driven gear at the wheel end.

[0026] Or

[0027] The first backlash is the sum of the backlashes between all adjacent two gears from the driving gear on the motor side to the first driven gear, and the first driven gear is one of the driven gears between the driving gear on the motor side and the driven gear at the wheel end.

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

[0029] Controlling the motor torque to complete the engagement of all unengaged gears from the driving gear on the motor side to the driven gear at the wheel end at a rate of change of the motor torque with respect to time with a first slope;

[0030] Controlling the motor torque to recover to the target torque at a rate of change of the motor torque with respect to time with a 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 accelerator.

[0031] In a second aspect, the present application provides a torque zero-crossing tooth surface engagement device based on speed difference, and the device includes:

[0032] A first control module, configured to control the motor torque to decay to zero in response to a shift between the forward gear and the reverse gear or the release and depression of the accelerator;

[0033] A calculation module, configured to calculate the expected motor speed at each electrical angle during the process of passing through the first backlash after the motor torque is reversed. The expected motor speed is determined according to the wheel-end speed corresponding to the electrical angle and the target speed difference, and the target speed difference is preset according to the area of the first backlash corresponding to the electrical angle;

[0034] A determination module, configured to determine the expected rate of change of the motor speed at the electrical angle according to the expected motor speed and the actual motor speed corresponding to the electrical angle;

[0035] A second control module, configured to perform PID control on the error between the actual rate of change of the motor speed corresponding to the electrical angle and the expected rate of change of the motor speed, and control the error to converge to zero;

[0036] A third control module, configured to control the motor torque to recover to the target torque until after passing through the first backlash.

[0037] In a third aspect, the present application provides a motor control device, including a memory and a processor. The memory is used to store instructions or codes, and the processor is used to execute the instructions or codes so that the device executes the above-mentioned method for torque zero-crossing tooth surface fitting based on speed difference.

[0038] The embodiments of the present application provide a method, device and equipment for torque zero-crossing tooth surface fitting based on speed difference. First, in response to the switch between the forward gear and the reverse gear or the release and depression of the accelerator pedal, the original torque of the motor is controlled to decay to zero. When the torque zero-crossing occurs, the current original torque will be quickly decayed to zero first, shortening the time of torque zero-crossing. Then, after the motor torque is reversed, during the process of passing through the first tooth side clearance, the expected motor speed of each electrical angle is calculated. The expected motor speed is determined according to 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 front section area of the first tooth side clearance is greater than the target speed difference corresponding to the electrical angle in the last section area. The electrical angle corresponding to the first tooth side clearance of the same vehicle is fixed, and the area or position in the first tooth side clearance is determined based on the electrical angle. And the expected motor speed is determined based on the target speed difference and the wheel end speed preset according to the current electrical angle. Since the target speed difference corresponding to the electrical angle in the front section area is greater than the target speed difference corresponding to the electrical angle in the last section area, it is possible to quickly disengage from the original mating tooth surface and complete the fitting at a lower target speed difference in the last section area. Finally, by combining the expected motor speed with the current actual motor speed, the change rate of the expected motor speed of the electrical angle is determined, and PID control is performed on the error between the current actual motor speed change rate and the expected motor speed change rate to control the error to converge to zero. In this way, based on the target speed difference, during the process of passing through the tooth side clearance, it is possible to quickly disengage from the original mating tooth surface, and then reduce the speed difference between the driving gear and the other tooth surface at the moment of mating, so as to achieve the effect of static meshing as much as possible, taking into account the shortening of the torque zero-crossing time and the reduction of impact, so as to improve the continuity and smoothness of the vehicle power output. Description of the Drawings

[0039] To more clearly illustrate the technical solutions in the embodiments or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0040] Figure 1 A schematic structural diagram of gear meshing provided for the background technology of the present application;

[0041] Figure 2 A schematic diagram of the process of torque zero-crossing control provided for the embodiments of the present application;

[0042] Figure 3 Flow chart of a differential - based torque - zero tooth - surface fitting method provided by an embodiment of the present application;

[0043] Figure 4 Schematic diagram of the control process of a differential - based torque - zero tooth - surface fitting method provided by an embodiment of the present application;

[0044] Figure 5 Schematic diagram of the structure of a differential - based torque - zero tooth - surface fitting device provided by an embodiment of the present application. Detailed implementation manners

[0045] Refer to Figure 1 In [reference], there are three states during torque zero - crossing, as shown in Figure 1 (a) is the state before torque zero - crossing, where the motor torque gradually decays from the original torque to zero, as shown in Figure 1 (b) is the state during torque zero - crossing. After the motor torque is reversed, the driving gear disengages from the original tooth surface of the driven gear and fits to another tooth surface through the tooth - side clearance, as shown in Figure 1 (c) is the state after torque zero - crossing. The driving gear fits to another tooth surface of the driven gear, and the torque continues to increase to the torque that the driver needs to drive. The switching moment between the state during torque zero - crossing and the state after torque zero - crossing is the collision point of the driving gear and the driven gear on another tooth surface.

[0046] Therefore, refer to Figure 2 In the schematic diagram of the torque zero - crossing control process shown, whether the torque changes from the negative direction to the positive direction or from the positive direction to the negative direction during torque zero - crossing, it is expected that the surface - changing process can pass slowly to reduce the surface - changing impact. Therefore, the change rate of the motor torque with time is reduced. Refer to Figure 2 (a), but the slope is still relatively large, and there is still a surface - changing impact. For further optimization, refer to Figure 2 (b). A reverse small - torque platform is formed within the tooth - shaft surface - changing zero - crossing interval to achieve the purpose of gliding and fitting the tooth surface during tooth - shaft surface - changing, greatly reducing the surface - changing impact. However, due to different clearances and stresses between the shaft systems, the speeds of the tooth shaft at the zero - crossing moment are different due to factors such as the deformation of the whole vehicle during the torque withdrawal process, and there are differences in the working conditions of the surface - changing impact points themselves, resulting in general robustness of the zero - crossing open - loop control. Therefore, a tooth - surface changing method based on closed - loop control of the target speed difference is further proposed. Refer to Figure 2 The actual torque of the motor in (c). Based on the target speed difference, the motor torque is controlled. During the process of passing through the tooth - side clearance, it is realized to quickly disengage from the original fitting tooth surface, and then the speed difference between the driving tooth surface and the other tooth surface at the moment of fitting of the driving gear and the driven gear needs to be reduced to achieve the effect of static meshing as much as possible, which can take into account the shortening of the zero - crossing time and the reduction of the impact.

[0047] Specifically, the present application proposes a tooth surface fitting method based on differential speed for torque zero crossing. First, in response to the switching between the forward gear and the reverse gear or the depression and release of the accelerator pedal, the original torque of the motor is controlled to decay to zero. When the torque zero crossing occurs, the current original torque is first rapidly decayed to zero to shorten the time of torque zero crossing. Then, 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 according to the wheel end speed corresponding to the electrical angle and the target differential speed. The target differential speed is preset according to the area of the first tooth side clearance corresponding to the electrical angle, and the target differential speed corresponding to the electrical angle in the front section area of the first tooth side clearance is greater than the target differential speed corresponding to the electrical angle in the last section area. The electrical angle corresponding to the first tooth side clearance of the same vehicle is fixed. Based on the electrical angle, the area or position where the current is in the first tooth side clearance is determined, and then the expected motor speed is determined based on the target differential speed and the wheel end speed preset according to the current electrical angle. The target differential speed corresponding to the electrical angle in the front section area is greater than the target differential speed corresponding to the electrical angle in the last section area, which is used to achieve rapid detachment from the original fitting tooth surface and complete the fitting at a lower target differential speed in the last section area. Finally, based on the combination of the expected motor speed and the current actual motor speed, the change rate of the expected motor speed of the electrical angle is determined, and PID control is performed on the error between the current actual motor speed change rate and the expected motor speed change rate to control the error to converge to zero. In this way, based on the target differential speed, during the process of passing through the tooth side clearance, the original fitting tooth surface can be rapidly detached, and then the differential speed between the driving gear and the other tooth surface at the moment of fitting can be reduced to achieve the effect of static meshing as much as possible, taking 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 the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0049] Figure 3 For the flowchart of a tooth surface fitting method based on differential speed for torque zero crossing provided by an embodiment of the present application, see Figure 3 A tooth surface fitting method based on differential speed for torque zero crossing includes:

[0050] S301. In response to the switching between the forward gear and the reverse gear or the depression and release of the accelerator pedal, control the original torque of the motor to decay to zero.

[0051] In a possible implementation manner, the forward gear is the R gear and the reverse gear is the D gear. When switching from the forward gear to the reverse gear or from the reverse gear to the forward gear, the original torque can be first controlled to decay to 0 at a large slope (the change rate of torque with time), shortening the time consumed by torque zero crossing and improving the user's driving experience.

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

[0053] The motor torque is transmitted through the gear drive and finally drives the wheels 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 a tooth side clearance between any two adjacent transmission gears to prevent the gear drive from jamming. However, during the torque reversal process when the torque passes through zero (switching from the original torque to the reverse torque in the opposite direction of the original torque direction), the driving side gear will disengage from the original tooth surface of the corresponding driven gear and engage with another tooth surface based on the reverse torque passing through the tooth side clearance.

[0054] Therefore, the first tooth side clearance is determined according to the tooth side clearances 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, due to the determined mechanical structure and tooth side clearance, and the electrical angle is determined by the integral of the speed difference between the driving gear and the driven gear with respect to time. Therefore, when the tooth side clearance is determined, the electrical angle is also determined. Therefore, when the torque passes through zero and the driving gear meshes with the corresponding driven gear through the first tooth side clearance, the area or position of passing through the first tooth side clearance can be determined based on the electrical angle, and according to the target speed differences in different areas of the corresponding first tooth side clearance, the target speed difference is added to the wheel end speed at the corresponding electrical angle to determine the expected motor speed.

[0056] S303. Determine the expected motor speed change rate of the electrical angle according to the expected motor speed and the actual motor speed corresponding to the electrical angle.

[0057] At the same electrical angle, the expected motor speed change rate is determined by combining the expected motor speed and the actual motor speed, and subsequent adjustments are made by considering the actual working conditions in combination 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 expected motor speed change rate to control the error to converge to zero.

[0059] Perform PID control on the error between the actual motor speed change rate and the expected motor speed change rate at the same electrical angle to achieve more precise motor control.

[0060] S305. Until after passing through the first flank clearance, control the motor torque to recover to the target torque.

[0061] Since the electrical angle corresponding to the first flank clearance is fixed, it is determined that the fitting of the first flank clearance is completed according to the electrical angle, and the first flank clearance is passed through.

[0062] In a possible implementation manner, after the gear meshing passing through the first flank clearance, the reverse torque can recover to the target torque at a relatively large slope (the rate of change of torque with time), and the relatively large slope is to shorten the time consumed for the torque to cross zero and improve the user's driving experience.

[0063] According to the above steps S301 - S305, it can be seen that in this application, before the torque crosses zero in step S301 and in step S305, a relatively large slope is used to control the motor torque to reduce the time consumed for the torque to cross zero. And in step S302, according to the first flank clearance, the target speed difference of the electrical angles corresponding to different regions of the first flank clearance is preset. Subsequently, according to the target speed difference and the wheel end speed, the desired motor speed is determined, and according to the desired motor speed and the actual motor speed, the actual working conditions are considered to determine the final desired motor speed change rate. Finally, the error between the actual motor speed change rate and the desired motor speed change rate at the same electrical angle is subjected to PID control to achieve more precise motor control. In this way, based on the fact that the target speed difference corresponding to the electrical angle in the front section area passing through the first flank clearance is greater than the target speed difference corresponding to the electrical angle in the rear section area, during the process of passing through the first flank clearance, it can quickly disengage from the original mating tooth surface, and then reduce the speed difference between the active tooth surface and the driven tooth surface at the moment of impact and mating with the other tooth surface, so as to achieve the effect of static meshing as much as possible, and both the shortening of the torque zero-crossing time and the reduction of the impact can be taken into account.

[0064] In the embodiment of this application, the above Figure 3 There are possible implementation manners for the step S302, which will be introduced separately below. It should be noted that the implementation manners given in the following introduction are only for illustrative purposes and do not represent all the implementation manners of the embodiment of this application.

[0065] In a possible implementation manner, the specific process of calculating the desired motor speed for each electrical angle during the process of passing through the first flank clearance is as follows:

[0066] Take the difference between the speed of the driving gear on the motor side and the speed of the driven gear on the wheel end and integrate it to obtain the electrical angle.

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

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

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

[0070] Sum the wheel end speed and the target speed difference to obtain the desired motor speed of the electrical angle.

[0071] Determine the desired motor speed based on the wheel end speed and the target speed difference, so as to adjust the motor based on the target speed difference.

[0072] Further, in the above embodiment, the preset method of the target speed difference can specifically be:

[0073] Preset the target speed difference of the electrical angle corresponding to each region according to passing through different regions of the first tooth side clearance; the electrical angle corresponding to the first tooth side clearance of the same vehicle is fixed.

[0074] Exemplarily, during the process that the driving gear on the driving side completes gear meshing through the first tooth side clearance, the regions that can specifically pass through the first tooth side clearance may include a first region and a second region.

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

[0076] Specifically, the region range of the first region is greater than the region range of the second region. For example, the range of the first region can account for two-thirds of the entire first tooth side clearance region, and the range of the second region can account for one-third of the entire first tooth side clearance region.

[0077] In the embodiment of the present application, the above Figure 3 Step S303 has possible implementation manners, which will be introduced separately below. It should be noted that the implementation manners given in the following introduction are only for exemplary illustration and do not represent all the implementation manners of the embodiment of the present application.

[0078] In a possible implementation manner, determine the desired motor speed change rate of the electrical angle according to the desired motor speed and the actual motor speed corresponding to the electrical angle. Specifically, it can be:

[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] Determine the desired motor speed change rate of the electrical angle corresponding to the speed difference by looking up a table.

[0082] In a possible implementation, the table for looking up values is the corresponding expected motor speed change rate determined based on experimental experience through the rotational speed difference.

[0083] In the embodiments of the present application, the above Figure 3 There are possible implementations for the first tooth side clearance in step S302 described above, which will be introduced separately below. It should be noted that the implementations given in the following introduction are only for illustrative purposes and do not represent all the implementations of the embodiments of the present application.

[0084] In the first possible implementation, the first tooth side clearance is one of the tooth side clearances between all adjacent two gears from the driving gear on the motor side to the driven gear on the wheel side.

[0085] Specifically, taking one of the tooth side clearances between all adjacent two gears from the driving gear on the motor side to the driven gear on the wheel side as the first tooth side clearance to approximate the tooth side clearance between the driving gear on the motor side and the driven gear on the wheel side. In this way, it is possible to simplify the control scheme and reduce the amount of calculation through approximate calculation with one tooth side clearance.

[0086] Exemplarily, the first tooth side clearance can be the maximum tooth side clearance among the tooth side clearances between all adjacent two gears from the driving gear on the motor side to the driven gear on the wheel side. That is, taking the maximum tooth side clearance as the first tooth side clearance to approximate the tooth side clearance between the driving gear on the motor side and the driven gear on the wheel side.

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

[0088] Specifically, taking the sum of the tooth side clearances between all adjacent two gears from the driving gear on the motor side to the driven gear on the wheel side as the first tooth side clearance to ensure that after passing through the first tooth side clearance, all the gears between the driving gear on the motor end and the driven gear on the wheel side can complete the fitting based on the reverse torque after the torque passes through zero.

[0089] Exemplarily, assume a transmission structure where the gears from the motor end to the wheel end sequentially include a first gear, a second gear, a third gear, and a fourth gear. Then calculate the sum of the tooth side clearances between the first gear and the second gear, between the second gear and the third gear, and between the third gear and the fourth gear as the first tooth side clearance of this transmission structure.

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

[0091] Exemplarily, the first driven gear can be the driven gear corresponding to the maximum flank clearance from the motor-side driving gear to the wheel-end driven gear. While reducing the calculation amount, the gears with the maximum flank clearance are also engaged at a low speed as much as possible.

[0092] Exemplarily, based on the above-mentioned transmission structure, if the flank clearance between the second gear and the third gear is the largest flank clearance in the transmission structure, then the sum of the flank clearance between the first gear and the second gear and the flank clearance between the second gear and the third gear is used as the first flank clearance of the transmission structure.

[0093] Further, based on the first possible implementation and the third possible implementation above, when partial gears are engaged, for the gears that are still not engaged after passing through the first flank clearance, additional control can be carried out in Figure 3 step S305 therein. Specifically, for controlling the motor torque to recover to the target torque, the specific steps can include:

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

[0095] Exemplarily, the time for setting the motor torque to control the torque change at the first slope can be determined according to experiments or experience. This time is greater than or equal to the time required to complete the engagement of all unengaged gears from the motor-side driving gear to the wheel-end driven gear at the first slope. The slope of the first slope is changed to ensure that when the unengaged gears are engaged, they can also be engaged at a low speed difference.

[0096] Step S3052: Control the motor torque to recover to the target torque at a rate of change of the motor torque with respect to time at a second slope. 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 control state of the driver's throttle.

[0097] Exemplarily, the second slope can be set corresponding to the slope of the torque decay in step S301, and after the engagement is completed, the target torque can be reached at a faster speed.

[0098] Exemplarily, the target torque is determined based on the control state of the driver's throttle. The deeper the driver steps on the throttle, the greater the target torque.

[0099] In the embodiments of the present application, the above-mentioned Figure 3 There are possible implementation manners for the PID control in step S304, which will be introduced separately below. It should be noted that the implementation manners given in the following introduction are only for illustrative purposes and do not represent all the implementation manners of the embodiments of the present 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 a driving force linked at the corresponding electrical angle. The desired angular acceleration is determined according to the change rate of the desired rotational speed.

[0101] In a possible implementation manner, 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] Exemplarily, based on the first to the third possible implementation manners above, the drive unit can be a motor, which simplifies the calculation amount.

[0103] In another possible implementation manner, the drive unit may further include a motor and a gear with a driving force linked at the current electrical angle. Then, the moment of inertia of the drive unit may include the moment of inertia of the motor and the moment of inertia of the gear with a driving force linked at the current electrical angle. Exemplarily, based on the third possible implementation manner or the third possible implementation manner, when determining the first backlash, when passing through the first backlash, the first gear corresponding to the current electrical angle of the first gear near the motor end meshes with the second gear, and the second gear will mesh with the third gear when transmitting backward through the corresponding backlash. Therefore, the moment of inertia of the drive unit can be the moment of inertia of the motor that generates the driving effect, the moment of inertia of the first gear, and the moment of inertia of the second gear.

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

[0105] The P-term coefficient of the PID control is determined by looking up the P-term coefficient table for 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 looking up the I-term coefficient table for 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 looking up the D-term coefficient table for the cumulative error corresponding to the electrical angle and the actual motor speed at the electrical angle.

[0108] The above-mentioned P-term coefficient table, I-term coefficient table, and D-term coefficient table can all be constructed based on experimental experience.

[0109] Based on the above embodiments, refer to Figure 4 the schematic diagram of the control process of a speed-difference-based torque zero-crossing tooth surface fitting method shown in

[0110] Among them, in the first process, torque control is performed, and the above-mentioned step S301 is executed to control the rapid decay of the motor torque. After decaying to 0, at this time, the driving side engages to drive the driven side to move, and the speed difference between the driving side and the driven side is 0.

[0111] In the second stage, speed control is performed. Through PID, speed closed-loop control is realized based on a preset target speed difference (the speed difference between the driving side and the driven side). In this stage, the above-mentioned steps S302 - S304 are executed. When passing through the first tooth side clearance at a relatively high speed and approaching the collision point (according to the electrical angle corresponding to the fitting process of the first tooth side clearance), the speed is controlled to decrease based on a lower target speed difference, with low torque and low speed, to prepare for static fitting. Then, finally, at the position of the collision point where the first tooth side clearance fitting is completed, a collision posture with low torque and low speed is achieved.

[0112] In the third stage, torque control is performed. When there are still un-fitted gears between the driving side and the driven side, the above-mentioned step S3051 can be executed to increase the reverse torque at a lower slope to complete the meshing of the un-fitted gears, and then step S3052 is executed to reach the target torque at a faster slope.

[0113] The above are some specific implementation manners of a speed-difference-based torque zero-crossing tooth surface fitting method provided by the embodiments of the present application. Based on this, the present application also provides a corresponding device. Next, the device provided by the embodiments of the present application will be introduced from the perspective of functional modularization.

[0114] Refer to Figure 5 the structural schematic diagram of a speed-difference-based torque zero-crossing tooth surface fitting device shown in

[0115] The first control module 501 is used to control the motor torque to decay to zero in response to the switching between the forward gear and the reverse gear or the release and press of 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 according to the wheel end speed corresponding to the electrical angle and the target speed difference, and the target speed difference is preset according to the area of the first tooth side clearance corresponding to the electrical angle;

[0117] The determination module 503 is used to determine the expected motor speed change rate of the electrical angle according to the expected motor speed and the actual motor speed corresponding to the electrical angle;

[0118] A second control module 504 is configured to perform PID control on an error between an 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.

[0119] A third control module 505 is configured to control the motor torque to recover to the target torque until after passing through the first backlash.

[0120] According to the above device, in the present application, before the torque of the first control module 501 crosses zero and after the torque of the third control module 505 crosses zero, a relatively large slope is used to control the motor torque, reducing the time consumed for the torque to cross zero. In the calculation module 502, according to the first backlash, a target speed difference corresponding to the electrical angle in different regions of the first backlash is preset. Subsequently, according to the target speed difference and the wheel-end speed, the desired motor speed is determined. In the determination module 503, according to the desired motor speed and the actual motor speed, the final desired motor speed change rate is determined considering the actual working conditions. In the second control module 504, PID control is performed on the error between the actual motor speed change rate and the desired motor speed change rate at 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 in the front section region of passing through the first backlash is greater than the target speed difference corresponding to the electrical angle in the end section region, during the process of passing through the first backlash, it is possible to quickly disengage from the original mating tooth surface, and then reduce the speed difference between the driving tooth surface and the driven tooth surface at the moment of impact and mating with the other tooth surface, so as to achieve the effect of static meshing as much as possible, and both the shortening of the torque zero-crossing time and the reduction of the impact can be taken into account.

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

[0122] Further, the preset method of the target speed difference may be to preset the target speed difference corresponding to the electrical angle of each region according to different regions passing through the first backlash; the electrical angle corresponding to the first backlash of the same vehicle is fixed.

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

[0124] In yet 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 a driving force that is linked at a corresponding electrical angle. The desired angular acceleration is determined according to the change rate of the desired 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 rotational speed at the electrical angle. The I-term coefficient of the PID control is determined by looking up the I-term coefficient table based on the motor torque corresponding to the electrical angle and the actual motor rotational speed at the electrical angle. The D-term coefficient of the PID control is determined by looking up the D-term coefficient table based on the cumulative error corresponding to the electrical angle and the actual motor rotational speed at the electrical angle.

[0125] In yet another possible implementation, the first backlash is the sum of the backlashes of all adjacent two gears between the driving gear on the motor side and the driven gear on the wheel side, or the first backlash is one of the backlashes of all adjacent two gears between the driving gear on the motor side and the driven gear on the wheel side, or the first backlash is the sum of the backlashes of all adjacent two gears between the driving gear on the motor side and the first driven gear, where the first driven gear is one of the driven gears between the driving gear on the motor side and the driven gear on the wheel side.

[0126] In yet another possible implementation, the third control module 505 is configured to control the motor torque to complete the fitting of all unfitted gears between the driving gear on the motor side and the driven gear on the wheel side at a rate of change of the motor torque with respect to time having a first slope, and to control the motor torque to return to the target torque at a rate of change of the motor torque with respect to time having a 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 control state of the driver on the accelerator.

[0127] The embodiments of the present application further provide corresponding motor control devices and computer storage media for implementing the solutions provided by the embodiments of the present application.

[0128] Among them, the motor control device includes a memory and a processor. The memory is used to store instructions or codes, and the processor is used to execute the instructions or codes so that the device executes a method for torque zero-crossing tooth surface fitting based on speed difference according to any embodiment of the present application.

[0129] The computer storage medium stores codes. When the codes are run, the device running the codes implements a method for torque zero-crossing tooth surface fitting based on speed difference according to any embodiment of the present application.

[0130] In the embodiments of the present application, the "first", "second" (if any) in names such as "the first" and "the second" are only used as name identifiers and do not represent the first and second in order.

[0131] From the description of the above embodiments, those skilled in the art can clearly understand that all or part of the steps in the above embodiment methods can be implemented by means of software plus a general hardware platform. Based on such an understanding, the technical solution of the present application can be embodied in the form of a software product, and the computer software product can be stored in a storage medium, such as read-only memory (ROM) / RAM, magnetic disk, optical disk, etc., including several instructions for causing a computer device (which can 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 the present application.

[0132] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple. For the relevant parts, reference can be made to the partial description of the method embodiments. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0133] The above description is only an exemplary embodiment of the present application and is not used to limit the protection scope of the present application.

Claims

1. A torque zero-crossing tooth surface fitting method based on speed difference, characterized in that: The method comprises: In response to switching between forward gear and reverse gear or releasing the accelerator, controlling the original torque of the motor to decay to zero; After the motor torque is commutated, the expected motor speed at each electrical angle during the process of passing through the first tooth side clearance is calculated, and the expected motor speed is determined according to the wheel end speed corresponding to the electrical angle and the target speed difference, and the target speed difference is preset according to the area where the electrical angle corresponds to the first tooth side clearance, and the target speed difference corresponding to the electrical angle of the front section area of ​​the first tooth side clearance is greater than the target speed difference corresponding to the electrical angle of the rear section area; Determining the expected motor speed change rate of the electrical angle according to the expected motor speed and the actual motor speed corresponding to the electrical angle; Performing 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 controlling the error to converge to zero; After the first tooth side clearance is passed, the motor torque is controlled to recover 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 process includes: The speed of the driving gear on the motor side is subtracted from the speed of the driven gear on the wheel end and then integrated to obtain the electrical angle. Obtaining the corresponding wheel end speed at the electrical angle; The wheel end speed and the target speed difference are summed to obtain the expected motor speed at the electrical angle.

3. The method according to claim 1, characterized in that The method for presetting the target speed difference is specifically as follows: According to different areas passing through the first tooth side clearance, a target speed difference of the electrical angle corresponding to each area is preset; the electrical angle corresponding to the first tooth side 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 according to the expected motor speed and the actual motor speed corresponding to the electrical angle includes: Calculating a speed difference between the expected motor speed and the actual motor speed corresponding to the electrical angle; The expected motor speed change rate of the electrical angle corresponding to the speed difference 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 expected 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 linked with a driving force at a corresponding electrical angle, and the expected angular acceleration is determined according to the expected speed change rate; The P-term coefficient of the PID control is determined by looking up the P-term coefficient table by the motor torque corresponding to the electrical angle and the actual motor speed of the electrical angle; The I-term coefficient of the PID control is determined by looking up the I-term coefficient table for the motor torque corresponding to the electrical angle and the actual motor speed of the electrical angle; The D-term coefficient of the PID control is determined by looking up the D-term coefficient table based on the accumulated error corresponding to the electrical angle and the actual motor speed of the electrical angle.

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

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

8. The method according to claim 7, characterized in that Control the motor torque to restore to the target torque, including: Controlling the motor torque to complete the fitting of all unfitted gears from the motor side driving gear to the wheel end driven gear at a first slope of the motor torque change rate over time; The motor torque is controlled to be restored to the target torque at a rate of change of the motor torque over time of a second slope, wherein an absolute value of the first slope is smaller than an absolute value of the second slope, and the target torque is determined based on a control state of the driver on the throttle.

9. A torque zero-crossing tooth surface fitting device based on speed difference, characterized in that: The device comprises: A first control module, for controlling the motor torque to decay to zero in response to switching between a forward gear and a reverse gear or releasing the accelerator; a calculation module, configured 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 commutated, wherein the expected motor speed is determined according to the wheel end speed corresponding to the electrical angle and a target speed difference, wherein the target speed difference is preset according to the area of ​​the electrical angle corresponding to the first tooth side clearance; A determination module, configured to determine the expected motor speed change rate of the electrical angle according to the expected motor speed and the actual motor speed corresponding to the electrical angle; A 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 expected motor speed change rate, so as 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 the first tooth side clearance.

10. A motor control device, characterized in that: It includes a memory and a processor, wherein the memory is used to store instructions or codes, and the processor is used to execute the instructions or codes so that the device executes a speed difference-based torque zero-crossing tooth surface fitting method as described in any one of claims 1-8.

Images