Gear backlash meshing torque control method and system

Abstract

This invention discloses a method and system for controlling gear backlash meshing torque. It can obtain the corresponding active damping compensation torque based on the motor's rotational speed and vibration frequency at the current moment. The active damping compensation torque is then superimposed with a pre-calibrated torque to obtain the control torque, wherein the pre-calibrated torque is the torque value corresponding to the current moment in the torque curve obtained from pre-calibrated vehicle calibration. Based on the control torque, the active gear driven by the motor is controlled to mesh with the corresponding driven gear. Therefore, this invention can accurately find the appropriate torque based on the pre-calibrated torque curve, and form the control torque through closed-loop control based on the active damping compensation torque. Then, the motor is controlled based on the control torque to drive the active gear and driven gear to mesh, effectively solving gear backlash noise and gear backlash vibration, with a relatively ideal suppression effect.

Description

Technical Field

[0001] This invention relates to the field of motor control, and in particular to a method and system for controlling gear backlash engagement torque. Background Technology

[0002] Currently, electric vehicles are developing rapidly. Generally, the powertrain of an electric vehicle consists of a motor connected via a drive shaft, drive gears, and driven gears. Due to the gap between the drive and driven gears, abnormal noises and vibrations can occur when releasing the accelerator, pressing the accelerator, starting the vehicle, and braking, affecting the driving experience. Currently, open-loop control strategies are generally used to suppress these noises and vibrations, but these methods are not effective in completely eliminating them, and the suppression effect is unsatisfactory. Summary of the Invention

[0003] In view of the above problems, the present invention provides a gear backlash engagement torque control method and system that overcomes or at least partially solves the above problems.

[0004] In a first aspect, a method for controlling gear backlash engagement torque includes:

[0005] Based on the motor's rotational speed and vibration frequency at the current moment, the corresponding active damping compensation torque is obtained.

[0006] The control torque is obtained by superimposing the active damping compensation torque with the corresponding pre-calibrated torque, wherein the pre-calibrated torque is the torque value corresponding to the current moment in the torque curve obtained by pre-calibrating the whole vehicle.

[0007] Based on the control torque, the active teeth driven by the motor are controlled to mesh with the corresponding driven teeth.

[0008] Optionally, in some optional embodiments, the vehicle calibration process for the torque curve includes:

[0009] The motor is powered on for the first time to obtain the minimum torque that makes the motor rotate;

[0010] A second power supply is supplied to the motor, and the motor is controlled to start from a stationary state and gradually increase the torque of the motor by increasing the step size by at least one torque value until the initial torque of tooth engagement and the target required torque are reached, thereby completing the calibration of the first stage curve. The initial torque of tooth engagement is equal to the minimum torque, and the target required torque is greater than the minimum torque.

[0011] Stop supplying power to the motor for the second time, and control the motor to gradually reduce the torque of the motor from the target required torque by a reduction step of at least one torque value until the tooth-stopping torque is reached, thereby completing the calibration of the first part of the second stage curve, wherein the tooth-stopping torque is equal to the minimum torque;

[0012] The motor is controlled to gradually reduce its torque to zero starting from the point where the tooth ends, with a preset torque value decreasing in step size, thereby completing the calibration of the latter part of the second stage curve;

[0013] Starting from the point where the torque of the motor decreases to zero, the torque of the motor is gradually reduced to negative torque by decreasing the step size by at least one torque value, thereby completing the calibration of the third-stage curve;

[0014] The motor is powered on for the third time, and the motor is controlled to gradually increase its torque to zero torque, starting from the negative torque and increasing the torque step by at least one torque value, thereby completing the calibration of the fourth stage curve.

[0015] The torque curve is obtained based on the first stage curve, the second stage curve, the third stage curve, and the fourth stage curve.

[0016] Optionally, in some alternative embodiments, the initial supply of power to the motor to obtain the minimum torque required to rotate the motor includes:

[0017] The first power supply is provided to the motor;

[0018] The minimum torque required to rotate the motor is obtained by reading the vehicle's overall message.

[0019] Optionally, in some optional embodiments, the second power supply to the motor, controlling the motor to start from a stationary state and gradually increase the motor torque to the starting torque and target required torque by increasing the torque step by at least one torque value, thereby completing the calibration of the first stage curve, includes:

[0020] A second power supply is provided to the motor;

[0021] Starting from the stationary state, the motor is controlled to gradually increase its torque to the initial torque of the tooth engagement step by step, starting with a first torque value;

[0022] The torque of the motor is controlled to gradually increase from the initial torque of the toothed motor to the target required torque by increasing the step size by at least one torque value, thereby completing the calibration of the first stage curve, wherein each of the increasing step sizes increases sequentially.

[0023] Optionally, in some optional embodiments, the step of controlling the motor torque to gradually increase from the initial gear torque to the target required torque by increasing the step size by at least one torque value, thereby completing the calibration of the first-stage curve, includes:

[0024] The second torque value is used to increase the step size, and the torque of the motor is controlled to increase continuously from the initial torque of the tooth according to a preset cycle for a first time length.

[0025] After the torque of the motor continues to increase for the first time length, the torque of the motor continues to increase for the second time length according to the preset period by increasing the step size by the third torque value, wherein the third torque value is greater than the second torque value;

[0026] After the torque of the motor continues to increase for the second time length, the torque is increased by a fourth torque value in increments, and the torque of the motor continues to increase for a third time length according to the preset cycle. This process is repeated until the torque of the motor increases to the target required torque, thereby completing the calibration of the first stage curve. The fourth torque value is greater than the third torque value.

[0027] Optionally, in some alternative implementations, the method further includes:

[0028] During the first time period during which the torque of the motor continues to increase: the driving tooth and the driven tooth engage.

[0029] Optionally, in some alternative implementations, stopping the second power supply to the motor and controlling the motor to gradually reduce the motor torque from the target required torque by at least one torque value in decreasing steps until the tooth-joining termination torque is reached, thereby completing the calibration of the first segment of the second-stage curve, includes:

[0030] Stop supplying power to the motor for the second time;

[0031] The fifth torque value is used to reduce the step size, and the torque of the motor is controlled to decrease continuously for a fourth time length, starting from the target required torque, according to the preset cycle.

[0032] After the torque of the motor continues to decrease for the fourth time length, the torque of the motor continues to decrease for the fifth time length according to the preset period, with a sixth torque value as the reduction step, wherein the sixth torque value is less than the fifth torque value;

[0033] After the torque of the motor continues to decrease for the fifth time length, the torque of the motor continues to decrease for the sixth time length according to the preset cycle, with the seventh torque value as the reduction step. This continues until the torque of the motor decreases to the tooth-stopping torque, thereby completing the calibration of the first segment of the second stage curve. The seventh torque value is less than the sixth torque value.

[0034] Optionally, in some alternative embodiments, controlling the motor to gradually reduce its torque to negative torque, starting from the point of zero torque, by decreasing the torque by at least one torque value in decreasing steps, thereby completing the calibration of the third-stage curve, includes:

[0035] Starting from the point where the motor torque is reduced to zero, the torque of the motor is gradually reduced to the negative torque by at least one torque value as a decreasing step, thereby completing the calibration of the third stage curve. The decreasing step values ​​increase sequentially. During the period when the motor torque is gradually reduced to the negative torque, the driving tooth and the driven tooth engage.

[0036] Optionally, in some optional embodiments, the calibration of the third-stage curve, starting from the zero torque of the motor and gradually reducing the torque of the motor to the negative torque by at least one torque value as a decreasing step, to complete the calibration, includes:

[0037] Starting from the point where the motor torque decreases to zero, the torque of the motor is controlled to decrease continuously for a seventh time period, with the eighth torque value as the decreasing step size, according to a preset cycle.

[0038] After the torque of the motor continues to decrease for the seventh time length, the torque of the motor continues to decrease for the eighth time length according to the preset period, with the ninth torque value as the decrease step. The ninth torque value is greater than the eighth torque value.

[0039] After the torque of the motor continues to decrease for the eighth time length, the torque of the motor continues to decrease for the ninth time length according to the preset cycle, with the tenth torque value as the reduction step. This process is repeated until the torque of the motor is reduced to a preset negative torque, thereby completing the calibration of the third stage curve. The tenth torque value is greater than the ninth torque value.

[0040] Optionally, in some alternative embodiments, the third power supply to the motor, controlling the motor to gradually increase its torque from the negative torque stage to the zero torque stage by increments of at least one torque value, thereby completing the calibration of the fourth-stage curve, includes:

[0041] The motor is supplied with power for the third time. Starting from the negative torque, the torque of the motor is gradually increased to the zero torque by increasing the step size by at least one torque value, thereby completing the calibration of the fourth stage curve. The step sizes decrease sequentially between each other.

[0042] Optionally, in some alternative embodiments, the third power supply to the motor, starting from the negative torque, gradually increases the motor torque to the zero torque by increments of at least one torque value, thereby completing the calibration of the fourth-stage curve, includes:

[0043] The third power supply is then provided to the motor;

[0044] Starting from the negative torque, the torque of the motor is controlled to increase by a step size of eleventh torque value according to a preset cycle, starting from the negative torque and continuously increasing for tenth time length.

[0045] After the torque of the motor continues to increase for the tenth time length, the torque of the motor continues to increase for the eleventh time length according to the preset period, with the twelfth torque value being less than the eleventh torque value.

[0046] After the torque of the motor continues to increase for the eleventh time length, the step size is increased by the thirteenth torque value. According to the preset cycle, the torque of the motor is controlled to continue to increase for the twelfth time length, and so on, until the torque of the motor increases to the zero torque, thereby completing the calibration of the fourth stage curve, wherein the thirteenth torque value is less than the twelfth torque value.

[0047] Optionally, in some optional embodiments, obtaining the torque curve based on the first stage curve, the second stage curve, the third stage curve, and the fourth stage curve includes:

[0048] The first stage curve and the second stage curve are merged and spliced ​​together end to end;

[0049] The second-stage curve is merged and spliced ​​with the third-stage curve;

[0050] The third-stage curve and the fourth-stage curve are merged and spliced ​​together to obtain the torque curve.

[0051] Optionally, in some alternative implementations, obtaining the corresponding active damping compensation torque based on the motor's rotational speed vibration frequency at the current moment includes:

[0052] Based on a bandpass filter, the rotational vibration frequency of the motor at the current moment is filtered to extract the corresponding rotational vibration signal;

[0053] Based on the PI controller, the active damping compensation torque output by the PI controller is obtained by using the rotational speed vibration signal and the setpoint of the PI controller.

[0054] Optionally, in some optional embodiments, the step of filtering the motor's rotational speed vibration frequency at the current moment based on a bandpass filter to extract the corresponding rotational speed vibration signal includes:

[0055] The high-frequency band of the rotational vibration frequency is filtered out by a bandpass filter, and the low-frequency band of the rotational vibration frequency is filtered out by a bandpass filter, thereby extracting the rotational vibration signal. The frequencies of the high-frequency band are all higher than the preset high cutoff frequency of the bandpass filter, and the frequencies of the low-frequency band are all lower than the preset low cutoff frequency of the bandpass filter.

[0056] Optionally, in some alternative embodiments, after calculating the active damping compensation torque output by the PI controller using the rotational speed vibration signal and the setpoint of the PI controller, the method further includes:

[0057] The active damping compensation torque output by the PI controller is limited to obtain the limited active damping compensation torque.

[0058] Optionally, in some optional embodiments, the step of superimposing the active damping compensation torque with a corresponding pre-calibrated torque to obtain the control torque includes:

[0059] The control torque is obtained by adding the active damping compensation torque to the corresponding pre-calibrated torque.

[0060] Optionally, in some alternative embodiments, controlling the engagement of the driving tooth driven by the motor with the corresponding driven tooth based on the control torque includes:

[0061] Based on the control torque, the corresponding pre-calibrated table is consulted to obtain the corresponding motor DQ axis current;

[0062] The motor is controlled based on the DQ axis current of the motor, so that the driving tooth and the driven tooth mesh together.

[0063] Optionally, in some alternative embodiments, the step of querying a pre-calibrated table based on the control torque to obtain the corresponding motor DQ shaft current includes:

[0064] If the control torque is within the preset small torque range, the corresponding pre-calibrated first table is consulted to obtain the corresponding motor DQ axis current. The lookup torque step size of the first table is N times the normal torque step size, which is equal to M times the maximum peak torque of the motor. Both N and M are greater than 0 and less than 1.

[0065] Optionally, in some alternative embodiments, the step of querying a pre-calibrated table based on the control torque to obtain the corresponding motor DQ shaft current includes:

[0066] If the control torque is outside the preset small torque range, the corresponding pre-calibrated second table is consulted to obtain the corresponding motor DQ axis current. The lookup torque step size of the second table is the normal torque step size, which is equal to M times the maximum peak torque of the motor, where M is greater than 0 and less than 1.

[0067] In a second aspect, a gear backlash meshing torque control system includes: a motor, a compensation torque calculation node, a torque superposition node, and a variable PI control current loop;

[0068] The motor is connected to the compensation torque calculation node, the compensation torque calculation node is connected to the torque superposition node, and the torque superposition node is connected to the variable PI control current loop;

[0069] The compensation torque calculation node is used to obtain the corresponding active damping compensation torque based on the motor's rotational speed at the current moment.

[0070] The torque superposition node is used to superimpose the active damping compensation torque with the corresponding pre-calibrated torque to obtain the control torque, wherein the pre-calibrated torque is the torque value corresponding to the current moment in the torque curve obtained by pre-calibrating the whole vehicle.

[0071] The variable PI control current loop is used to control the active tooth driven by the motor to mesh with the corresponding driven tooth based on the control torque.

[0072] By employing the above technical solution, the present invention provides a gear backlash meshing torque control method and system. This method can obtain the corresponding active damping compensation torque based on the motor's rotational speed vibration frequency at the current moment. The active damping compensation torque is then superimposed with a pre-calibrated torque to obtain the control torque, where the pre-calibrated torque is the torque value corresponding to the current moment in the torque curve obtained from pre-calibrated vehicle calibration. Based on the control torque, the active gear driven by the motor is controlled to mesh with the corresponding driven gear. Therefore, the present invention can accurately find the appropriate torque based on the pre-calibrated torque curve, and form the control torque through closed-loop control based on the active damping compensation torque. Then, the motor is controlled based on the control torque to drive the active gear and driven gear to mesh, effectively solving gear tooth-grip noise and gear tooth-grip vibration, with a relatively ideal suppression effect.

[0073] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0074] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0075] Figure 1 A flowchart of a gear backlash engagement torque control method provided by the present invention is shown;

[0076] Figure 2 A flowchart of a strategy for varying PI coefficients provided by the present invention is shown;

[0077] Figure 3 A flowchart illustrating the vehicle calibration process for a torque curve provided by the present invention is shown.

[0078] Figure 4 A schematic diagram of a gear backlash torque control system provided by the present invention is shown.

[0079] Figure 5 A schematic diagram of the structure of an electronic device provided by the present invention is shown. Detailed Implementation

[0080] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0081] like Figure 1 As shown, the present invention provides a method for controlling gear backlash meshing torque, including: S100, S200 and S300;

[0082] S100. Based on the motor's rotational speed and vibration frequency at the current moment, the corresponding active damping compensation torque is obtained.

[0083] Optionally, the motor mentioned in this invention can be a motor in an electric vehicle. During motor operation, the executing entity of this invention can obtain the corresponding rotational speed vibration frequency. For example, this invention can acquire vehicle messages (carrying motor speed signals) based on a CAN box (also known as a CANBUS analyzer) or obtain the motor speed signal during vehicle operation based on other related devices, and then calculate the rotational speed vibration frequency corresponding to the speed signal.

[0084] Optionally, the present invention does not limit the process of calculating the active damping compensation torque based on the rotational vibration frequency, and any feasible implementation is within the protection scope of the present invention. For example, in some optional implementations, S100 includes: steps 1.1 and 1.2;

[0085] Step 1.1: Based on a bandpass filter, filter the rotational speed vibration frequency of the motor at the current moment to extract the corresponding rotational speed vibration signal;

[0086] Optionally, bandpass filters are a well-known concept in the art, and this invention will not describe them in detail; please refer to relevant descriptions in the art for specific details. It should be noted that bandpass filters can be set with corresponding high and low cutoff frequencies to filter out the corresponding high and low frequency bands in the rotational vibration frequency.

[0087] That is, in some optional implementations, step 1.1 includes:

[0088] The high-frequency band of the rotational vibration frequency is filtered out by a bandpass filter, and the low-frequency band of the rotational vibration frequency is filtered out by a bandpass filter, thereby extracting the rotational vibration signal. The frequencies of the high-frequency band are all higher than the preset high cutoff frequency of the bandpass filter, and the frequencies of the low-frequency band are all lower than the preset low cutoff frequency of the bandpass filter.

[0089] Optionally, the present invention can simultaneously filter out high-frequency and low-frequency bands, or it can filter out low-frequency bands after filtering out high-frequency bands. Of course, the present invention can also filter in multiple steps: filtering out only high-frequency bands and filtering out only low-frequency bands, and then subtracting the two filtering results to obtain the rotational speed vibration signal. The present invention does not limit this.

[0090] Optionally, the motor speed fluctuation frequency can be obtained through a bandpass filter, and this invention does not limit this.

[0091] Step 1.2: Based on the PI controller, the active damping compensation torque output by the PI controller is calculated using the rotational speed vibration signal and the setpoint of the PI controller.

[0092] Optionally, the PI controller (also known as a proportional-integral controller) is a well-known concept in the art, and will not be described in detail here. Please refer to relevant descriptions in the art for specific details. It should be noted that the calibration scheme for the proportional-integral coefficients of the PI controller is as follows:

[0093] Based on the analysis of the vehicle's message data, the amplitude and frequency of the speed vibration are determined. First, the proportional coefficient of the PI controller is increased, and the amplitude of the speed vibration is observed to decrease. If it decreases, it is increased further until the amplitude of the speed vibration remains almost constant. If the amplitude of the speed vibration remains almost constant, the proportional coefficient is maintained. Then, the integral coefficient is increased until the amplitude of the speed vibration does not decrease after a few steps. At this point, it indicates that the calibration of the proportional-integral coefficient of the PI controller has been completed.

[0094] Optionally, due to the inherent characteristics of PI controllers, using a large PI coefficient can lead to overshoot, causing overcurrent in the motor controller and, in severe cases, even causing the switching transistor to explode. However, a smaller PI coefficient will result in poorer current tracking performance and a slower dynamic response. A slower dynamic response leads to a slower torque response, especially when the torque is low, as the difference between the current setpoint and the feedback value is small, resulting in an even slower current dynamic response. Generally, to avoid overcurrent faults when the current is high, a smaller PI coefficient is chosen, sacrificing some torque response speed.

[0095] Based on the above analysis, the tooth engagement stage is the stage where the motor's torque is relatively small (preset small torque range), resulting in a slower dynamic torque response, which further affects the acceleration performance when the accelerator is pressed and the energy feedback performance when the accelerator is released. In summary, this invention proposes a variable PI coefficient strategy during the tooth engagement stage. That is, when the motor is executing a small torque, the motor current is relatively small, and using a larger PI coefficient will not cause overcurrent problems; while when the current is relatively large, a smaller PI coefficient is used to solve the overcurrent problem when the current is large. For details, please refer to... Figure 2 The flowchart shows the strategy of varying PI coefficients.

[0096] Depend on Figure 2 It can be seen that the strategy of varying the PI coefficient is as follows: when the motor's operating torque is below a certain initial torque threshold, a larger PI coefficient is selected; when the motor's operating torque is between the initial torque threshold and the termination torque threshold, a linear transition is used to switch to a smaller PI coefficient; when the motor's operating torque is above the termination torque threshold, a smaller PI coefficient is selected. Generally, the initial torque threshold is smaller than the termination torque threshold. The selection of the initial torque threshold and the termination torque threshold can be obtained from the vehicle calibration, while the larger and smaller PI coefficients can be selected based on the results of the motor bench calibration.

[0097] Optionally, in some alternative embodiments, after step 1.2, the method further includes: limiting the active damping compensation torque output by the PI controller to obtain the limited active damping compensation torque.

[0098] Optionally, the active damping compensation torque output by the PI controller should not be too large to avoid affecting the overall vehicle's power performance. This invention allows setting a maximum active damping compensation torque output by the PI controller, which can be obtained based on vehicle calibration. Furthermore, if the control torque obtained by adding the active damping compensation torque to the calibrated torque exceeds the compensation exit torque threshold, this invention can exit the active damping compensation torque, where the compensation exit torque threshold can also be obtained based on vehicle calibration.

[0099] S200. The active damping compensation torque is superimposed with the corresponding pre-calibrated torque to obtain the control torque, wherein the pre-calibrated torque is the torque value corresponding to the current moment in the torque curve obtained by pre-calibrating the whole vehicle.

[0100] Optionally, the horizontal axis of the torque curve in this invention can be time, and the vertical axis can be torque. The corresponding torque can be found from the torque curve by the current time in S100. This invention does not limit this.

[0101] Optionally, the present invention does not limit the method of superimposing torque as described above. For example, in some optional embodiments, step S200 includes: adding the active damping compensation torque to the corresponding pre-calibrated torque to obtain the control torque.

[0102] Optionally, the torque mentioned in this invention can be positive torque, zero torque, or negative torque. When adding the torques, they can be added in a mathematical manner.

[0103] Optionally, this invention does not impose specific limitations on the vehicle calibration process for the torque curve; any feasible method falls within the scope of protection of this invention. For example, such as... Figure 3As shown, in some optional embodiments, the vehicle calibration process of the torque curve includes: S1000, S2000, S3000, S4000, S5000, S6000 and S7000.

[0104] S1000: Supply power to the motor for the first time to obtain the minimum torque that makes the motor rotate;

[0105] Optionally, the present invention can first supply power to the motor of the vehicle in a stationary state, and collect the minimum torque required to change the motor from a stationary state to a rotating state. Specifically, the present invention can obtain the aforementioned minimum torque by acquiring vehicle messages and then analyzing the vehicle messages.

[0106] That is, in some optional implementations, S1000 includes: steps 2.1 and 2.2;

[0107] Step 2.1: Provide the motor with the first power supply;

[0108] Step 2.2: Obtain the minimum torque required to rotate the motor by reading the vehicle's overall message.

[0109] It should be noted that, from the perspective of the entire vehicle, this invention can supply power to the motor by pressing the accelerator pedal (which can also be understood as the ignition switch), and completely releasing the accelerator pedal can be understood as disconnecting the power supply. Therefore, this invention does not limit the depth of pressing the accelerator pedal during the initial power supply; it can be fully depressed or lightly depressed, as long as it is pressed to a certain depth.

[0110] Optionally, after the minimum torque is detected, the present invention can disconnect the first power supply to facilitate the subsequent second power supply.

[0111] S2000: Power the motor a second time, control the motor to start from a stationary state, and gradually increase the torque of the motor to the starting torque of tooth engagement and the target required torque by increasing the step size by at least one torque value, thereby completing the calibration of the first stage curve, wherein the starting torque of tooth engagement is equal to the minimum torque, and the target required torque is greater than the minimum torque;

[0112] Optionally, the motor can also start from a standstill during the second power supply. That is, it can start from a state where the motor is not rotating.

[0113] Optionally, during the calibration of the first-stage curve, the motor torque needs to be gradually increased, but the step size (increase step size) can be the same or different each time.

[0114] Optionally, the target torque requirement mentioned in this invention can be understood as the torque required by the driver. Specifically, this invention can calculate the target torque requirement based on throttle depth, or it can directly obtain the target torque requirement from other systems; this invention does not impose any limitations on this.

[0115] Optionally, in some alternative implementations, step S2000 includes: steps 3.1, 3.2, and 3.3;

[0116] Step 3.1: Provide a second power supply to the motor;

[0117] Step 3.2: Starting from the stationary state, control the motor to gradually increase the torque of the motor to the starting torque of the tooth engagement by increasing the step size by the first torque value;

[0118] Optionally, this invention does not impose a specific limitation on the time taken to gradually increase the motor torque to the initial torque of the tooth contact by increasing the step size with a first torque value. The specific time depends on the magnitude of the initial torque of the tooth contact and the magnitude of the first torque value, and this invention does not impose any limitations on this.

[0119] Optionally, the first torque value is obtained based on the vehicle calibration. The basic rule for selecting the first torque value is that it needs to meet the power requirements of the vehicle when the accelerator is pressed.

[0120] Step 3.3: By increasing the step size by at least one torque value, control the torque of the motor to gradually increase from the initial torque of the toothed motor to the target required torque, thereby completing the calibration of the first stage curve;

[0121] The step size increases sequentially for each step.

[0122] Optionally, the present invention does not impose specific limitations on the time taken for the torque of the motor to gradually increase from the initial torque of the toothed motor to the target required torque by increasing the step size by at least one torque value.

[0123] Optionally, if the process of gradually increasing the motor torque from the initial torque near the teeth to the target torque uses multiple increment steps, then each increment step increases sequentially in chronological order. Of course, the increment steps do not necessarily have to be sequentially increasing. For example, the increment steps can be in a relationship of both increasing and decreasing. For instance, several consecutive increment steps may be sequentially increasing, followed by at least one subsequent increment step that is sequentially decreasing. That is, each increment step can be larger or smaller than the previous increment step, and this invention does not impose any restrictions on this.

[0124] For example, in some alternative implementations, step 3.3 includes: steps 4.1, 4.2, and 4.3;

[0125] Step 4.1: Increasing the step size by the second torque value, and controlling the torque of the motor to continuously increase from the initial torque of the toothed part according to the preset cycle for the first time length;

[0126] Optionally, the second torque value can be greater than, equal to, or less than the first torque value. Generally, the second torque value is less than the first torque value; this invention does not impose any limitation on this. It should be noted that the second torque value and the first time length are obtained through vehicle calibration, and they basically need to ensure that gear noise is within an acceptable range, while the power performance meets the requirements. Through repeated adjustments, the vehicle is brought to a relatively good state, where both power performance and gear noise requirements are met.

[0127] Optionally, this invention does not impose specific limitations on the preset period; any feasible method falls within the scope of protection of this invention. For example, if the preset period is 1 millisecond, then the motor torque is increased once every 1 millisecond, with each increase in torque being a second torque value. If the first time length is 10 milliseconds, then the motor torque is increased 10 times during the first time length, each time increasing by a first torque value. It should be noted that the preset period described in this invention applies to all increase and decrease step sizes. That is, different increase and decrease step sizes all use the same preset period.

[0128] Optionally, in some alternative implementations, the method further includes:

[0129] During the first time period during which the torque of the motor continues to increase: the driving tooth and the driven tooth engage.

[0130] It should be noted that during the initial period of continuous increase in motor torque, the driving tooth can move forward and engage with the driven tooth.

[0131] Step 4.2: After the torque of the motor continues to increase for the first time length, the torque of the motor continues to increase for the second time length according to the preset period by increasing the step size by the third torque value, wherein the third torque value is greater than the second torque value;

[0132] Optionally, for step 4.2, please refer to step 4.1 above for analogy and understanding; the present invention will not elaborate further on this.

[0133] Step 4.3: After the torque of the motor continues to increase for the second time length, the fourth torque value is used as the step size, and the torque of the motor is controlled to continue to increase for the third time length according to the preset cycle, and so on, until the torque of the motor increases to the target required torque, thereby completing the calibration of the first stage curve, wherein the fourth torque value is greater than the third torque value.

[0134] Optionally, before the motor torque increases to the target required torque, the present invention may use any number of different torque values ​​as the increment step, and the present invention does not limit this.

[0135] S3000, Stop supplying power to the motor for the second time, and control the motor to gradually reduce the torque of the motor from the target required torque by at least one torque value in decreasing step size until the tooth-end torque is reached, thereby completing the calibration of the first part of the second stage curve;

[0136] Wherein, the tooth-stopping torque is equal to the minimum torque;

[0137] Optionally, the endpoint of the aforementioned first-stage curve corresponds to the target torque requirement. Therefore, the present invention can start from the endpoint of the first-stage curve and then perform calibration of the first segment of the second-stage curve.

[0138] Optionally, during the calibration process in the initial segment of the second-stage curve, the motor torque needs to be gradually reduced until it reaches the torque required to terminate at the gear teeth. Therefore, this invention can use one or more different reduction step sizes during the process of gradually reducing the motor torque, and this invention does not impose any limitations on this.

[0139] For example, in some optional implementations, S3000 includes: steps 5.1, 5.2, 5.3, and 5.4;

[0140] Step 5.1: Stop supplying power to the motor for the second time;

[0141] Step 5.2: Using the fifth torque value as the decreasing step size, according to the preset cycle, control the torque of the motor to continuously decrease from the target required torque for the fourth time length.

[0142] Optionally, taking a preset period of 0.1 milliseconds and a fourth time length of 10 milliseconds as an example, during the fourth time length, the present invention reduces the motor torque every 0.1 milliseconds, each time reducing the fifth torque value; the present invention does not impose any limitations on this.

[0143] Step 5.3: After the torque of the motor continues to decrease for the fourth time length, the torque of the motor continues to decrease for the fifth time length according to the preset cycle, with the sixth torque value as the reduction step size, wherein the sixth torque value is less than the fifth torque value;

[0144] Optionally, for step 5.3, please refer to step 5.2 for analogy and understanding; the present invention will not elaborate further on this.

[0145] Step 5.4: After the torque of the motor continues to decrease for the fifth time length, the torque of the motor continues to decrease for the sixth time length according to the preset cycle, with the seventh torque value as the reduction step. This continues until the torque of the motor decreases to the tooth termination torque, thereby completing the calibration of the first segment of the second stage curve. The seventh torque value is less than the sixth torque value.

[0146] Optionally, before the motor torque is reduced to the tooth termination torque, the present invention may use any number of different reduction steps to gradually reduce the motor torque, and the present invention does not limit this.

[0147] It should be noted that before the motor torque decreases to the tooth termination torque, the reduction step sizes used in this invention exhibit an overall decreasing trend. Of course, the reduction step sizes do not necessarily have to be sequentially decreasing. For example, the reduction step sizes can be in a relationship of both increasing and decreasing. For instance, several consecutive reduction step sizes may be sequentially decreasing, followed by at least one subsequent reduction step size that is sequentially increasing. That is, each reduction step size can be larger or smaller than the previous one; this invention does not impose any restrictions on this.

[0148] Optionally, the final torque output results in a smoother curve for the motor's torque reduction, with almost no vibration in the vehicle during torque reduction. This requires balancing the conflict between the vehicle's calibrated energy recovery time and gear noise during throttle release, bringing both to a relatively acceptable level. Ultimately, this achieves a relatively acceptable level of gear noise, power, and energy recovery performance, thus satisfying overall vehicle performance requirements.

[0149] S4000: Control the motor to gradually reduce the torque of the motor to zero torque by decreasing the step size with a preset torque value, starting from the torque of the tooth stop. This completes the calibration of the latter part of the second stage curve.

[0150] Optionally, the preset torque value mentioned in this invention can be set according to the actual vehicle calibration requirements, and this invention does not impose any restrictions on it.

[0151] Optionally, the first segment of the second-stage curve and the second segment of the second-stage curve can be spliced ​​together to form a complete second-stage curve.

[0152] S5000: Starting from the point where the torque of the motor decreases to zero, the torque of the motor is gradually reduced to negative torque by decreasing the step size by at least one torque value, thereby completing the calibration of the third stage curve.

[0153] Optionally, after the second power supply is stopped, the motor torque decreases to zero according to the calibration curve, and the vehicle enters the energy recovery phase. Thereafter, the present invention uses the same torque step-size segmentation method to make the motor execute negative torque. The difference from positive torque increases or decreases is that it does not require calibration of the tooth-fitting start torque and tooth-fitting end torque; it only requires controlling the motor with gradually increasing torque steps, aiming to make the torque executed by the motor smooth and the entire vehicle vibration-free.

[0154] For example, in some alternative implementations, S5000 includes: step 6.1;

[0155] Step 6.1: Starting from the point where the motor torque is reduced to zero, control the motor torque to gradually decrease to the negative torque by decreasing the step size by at least one torque value, thereby completing the calibration of the third stage curve;

[0156] During the process where the reduction step size increases sequentially and the torque of the motor gradually decreases to the negative torque, the driving tooth and the driven tooth engage.

[0157] Optionally, as the motor torque gradually decreases to negative torque, the driving tooth can move backward to engage with the driven tooth.

[0158] Optionally, in some alternative implementations, step 6.1 includes: steps 7.1, 7.2, and 7.3;

[0159] Step 7.1: Starting from the point where the motor torque is reduced to zero, the torque of the motor is controlled to decrease continuously for a seventh time period according to the eighth torque value and the preset cycle.

[0160] Step 7.2: After the torque of the motor continues to decrease for the seventh time length, the torque of the motor continues to decrease for the eighth time length according to the preset cycle, with the ninth torque value as the decrease step size, wherein the ninth torque value is greater than the eighth torque value;

[0161] Step 7.3: After the torque of the motor continues to decrease for the eighth time length, the torque of the motor continues to decrease for the ninth time length according to the preset cycle, with the tenth torque value as the reduction step. This continues until the torque of the motor is reduced to the preset negative torque, thereby completing the calibration of the third stage curve. The tenth torque value is greater than the ninth torque value.

[0162] Optionally, the present invention does not impose specific limitations on the magnitude of the preset negative torque, which can be set according to actual needs.

[0163] S6000: Supply power to the motor for the third time, and control the motor to gradually increase the torque of the motor to the zero torque by increasing the step size by at least one torque value, starting from the negative torque, thereby completing the calibration of the fourth stage curve;

[0164] After pressing the accelerator again (the third power supply), the torque executed by the motor changes from negative to positive. During the phase where the executed torque changes from negative to zero, a method of gradually decreasing torque steps is used to approach zero torque, again requiring a smooth torque curve. At this point, the torque curve executed by the motor across the entire torque range can be obtained. A smooth curve results in no vehicle vibration, and gear noise is effectively suppressed.

[0165] For example, in some alternative implementations, S6000 includes: step 8.1;

[0166] Step 8.1: Supply power to the motor for the third time, starting from the negative torque, and gradually increase the torque of the motor to the zero torque by increasing the step size by at least one torque value, thereby completing the calibration of the fourth stage curve;

[0167] The increments decrease sequentially.

[0168] Optionally, in some alternative implementations, step 8.1 includes: steps 9.1, 9.2, 9.3, and 9.4;

[0169] Step 9.1: Provide the motor with power for the third time;

[0170] Step 9.2: Starting from the negative torque, increase the step size by the eleventh torque value, and control the motor torque to continuously increase the tenth time length starting from the negative torque according to the preset cycle;

[0171] Step 9.3: After the torque of the motor continues to increase for the tenth time length, the step size is increased by the twelfth torque value, and the torque of the motor continues to increase for the eleventh time length according to the preset cycle, wherein the twelfth torque value is less than the eleventh torque value;

[0172] Step 9.4: After the torque of the motor continues to increase for the eleventh time length, the step size is increased by the thirteenth torque value. According to the preset cycle, the torque of the motor is controlled to continue to increase for the twelfth time length, and so on, until the torque of the motor increases to the zero torque, thereby completing the calibration of the fourth stage curve, wherein the thirteenth torque value is less than the twelfth torque value.

[0173] S7000: The torque curve is obtained based on the first stage curve, the second stage curve, the third stage curve, and the fourth stage curve.

[0174] Optionally, in some alternative implementations, S7000 includes: steps 10.1, 10.2, and 10.3;

[0175] Step 10.1: Merge and splice the first stage curve and the second stage curve end to end;

[0176] Step 10.2: Merge and splice the second-stage curve with the third-stage curve.

[0177] Step 10.3: Merge and splice the third-stage curve and the fourth-stage curve to obtain the torque curve.

[0178] In summary, the torque curve calibration process was conducted while effectively suppressing gear-related noise, and also achieved some balance between acceleration and energy recovery performance. However, it still reduced acceleration performance when accelerating and energy recovery performance when releasing the accelerator. Therefore, this invention can add an active damping strategy based on the calibrated torque curve, using a closed-loop control strategy to suppress speed fluctuations during the gear-related phase, thereby correcting the calibrated torque curve. This further suppresses gear-related noise while reducing the execution time of smaller torque steps, improving the vehicle's acceleration and energy recovery performance.

[0179] S300. Based on the control torque, control the active tooth driven by the motor to mesh with the corresponding driven tooth.

[0180] Optionally, the motor is actually controlled by current. Therefore, the present invention can determine the corresponding current based on the control torque to control the motor's operation.

[0181] For example, in some alternative implementations, S300 includes: steps 11.1 and 11.2;

[0182] Step 11.1 Based on the control torque, consult the corresponding pre-calibrated table to obtain the corresponding motor DQ shaft current;

[0183] Optionally, the motor DQ axis current is a well-known concept in the art, and this invention will not describe it in detail. Please refer to the relevant descriptions in the art for details.

[0184] Optionally, in some alternative implementations, step 11.1 includes: step 12.1;

[0185] Step 12.1: If the control torque is within the preset small torque range, then query the corresponding pre-calibrated first table to obtain the corresponding motor DQ axis current. The lookup torque step size of the first table is N times the normal torque step size. The normal torque step size is equal to M times the maximum peak torque of the motor. Both N and M are greater than 0 and less than 1.

[0186] Optionally, when calibrating the motor DQ axis current on the test bench, the step size used in the calibration process is the aforementioned lookup torque step size. That is, in the first table obtained after final calibration, the lookup torque (two adjacent lookup torques differ by one lookup torque step size) and the corresponding motor DQ axis current are key-value pairs. When the aforementioned control torque is within the preset small torque range, it indicates that the motor is in the gear engagement stage, i.e., in the small torque execution stage. Therefore, this invention can obtain a more accurate motor DQ axis current based on the first table.

[0187] Optionally, the maximum peak torque of the motor is a value that can be known by referring to the instructions. If the first table is constructed using the normal torque step size calculated from this maximum peak torque, the resulting first table will not be accurate enough in terms of query precision, and the query results will naturally also be inaccurate. Therefore, for motors in the gear engagement stage, the first table in step 12.1 should be used to query the corresponding motor DQ shaft current to improve the accuracy of the present invention.

[0188] Optionally, in some alternative implementations, step 11.1 includes: step 13.1;

[0189] Step 13.1: If the control torque is outside the preset small torque range, then query the corresponding pre-calibrated second table to obtain the corresponding motor DQ axis current. The lookup torque step size of the second table is the normal torque step size, which is equal to M times the maximum peak torque of the motor, where M is greater than 0 and less than 1.

[0190] Optionally, if the controlled torque is outside the preset low torque range, it indicates that the motor is in the high torque stage, and the accuracy requirement can be appropriately relaxed. Therefore, the present invention can use the second table to look up the corresponding motor DQ axis current.

[0191] Step 11.2: Control the operation of the motor based on the DQ axis current of the motor, so that the driving tooth and the driven tooth mesh.

[0192] Optionally, if the control torque is outside the preset small torque range, it indicates that the current stage is not the gear engagement stage. That is, it is not necessary to achieve the stage from gear disengagement to gear engagement. Therefore, based on step 13.1, "making the driving tooth and the driven tooth engage" in step 11.1 can be understood as maintaining the gear engagement state.

[0193] like Figure 4 As shown, the present invention provides a gear backlash engagement torque control system, including: a motor 100, a compensation torque calculation node 200, a torque superposition node 300, and a variable PI control current loop 400.

[0194] The motor 100 is connected to the compensation torque calculation node 200, the compensation torque calculation node 200 is connected to the torque superposition node 300, and the torque superposition node 300 is connected to the variable PI control current loop 400.

[0195] The compensation torque calculation node 200 is used to obtain the corresponding active damping compensation torque based on the rotational speed of the motor 100 at the current moment.

[0196] The torque superposition node 300 is used to superimpose the active damping compensation torque with the corresponding pre-calibrated torque to obtain the control torque, wherein the pre-calibrated torque is the torque value corresponding to the current moment in the torque curve obtained by pre-calibrating the whole vehicle.

[0197] The variable PI control current loop 400 is used to control the active teeth driven by the motor 100 to mesh with the corresponding driven teeth based on the control torque.

[0198] The present invention provides a computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements the gear backlash engagement torque control method described in any of the preceding claims.

[0199] like Figure 5As shown, the present invention provides an electronic device 70, which includes at least one processor 701, at least one memory 702 and a bus 703 connected to the processor 701; wherein the processor 701 and the memory 702 communicate with each other through the bus 703; the processor 701 is used to call program instructions in the memory 702 to execute the gear backlash torque control method described above.

[0200] In this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0201] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0202] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined in this invention may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0203] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method for controlling gear backlash engagement torque, characterized in that, include: Based on the motor's rotational speed and vibration frequency at the current moment, the corresponding active damping compensation torque is obtained. The control torque is obtained by superimposing the active damping compensation torque with the corresponding pre-calibrated torque, wherein the pre-calibrated torque is the torque value corresponding to the current moment in the torque curve obtained by pre-calibrating the whole vehicle. Based on the control torque, the active teeth driven by the motor are controlled to mesh with the corresponding driven teeth; The vehicle calibration process for the torque curve includes: The motor is powered on for the first time to obtain the minimum torque that makes the motor rotate; A second power supply is supplied to the motor, and the motor is controlled to start from a stationary state and gradually increase the torque of the motor by increasing the step size by at least one torque value until the initial torque of tooth engagement and the target required torque are reached, thereby completing the calibration of the first stage curve. The initial torque of tooth engagement is equal to the minimum torque, and the target required torque is greater than the minimum torque. Stop supplying power to the motor for the second time, and control the motor to gradually reduce the torque of the motor from the target required torque by a decreasing step size of at least one torque value until the tooth-stopping torque is reached, thereby completing the calibration of the first part of the second stage curve, wherein the tooth-stopping torque is equal to the minimum torque; The motor is controlled to gradually reduce its torque to zero starting from the point where the tooth ends, with a preset torque value decreasing in step size, thereby completing the calibration of the latter part of the second stage curve; Starting from the point where the torque of the motor decreases to zero, the torque of the motor is gradually reduced to negative torque by decreasing the step size by at least one torque value, thereby completing the calibration of the third-stage curve; The motor is powered on for the third time, and the motor is controlled to gradually increase its torque to zero torque, starting from the negative torque and increasing the torque step by at least one torque value, thereby completing the calibration of the fourth stage curve. The torque curve is obtained based on the first stage curve, the second stage curve, the third stage curve, and the fourth stage curve.

2. The method according to claim 1, characterized in that, The first power supply to the motor to obtain the minimum torque required to rotate the motor includes: The first power supply is provided to the motor; The minimum torque required to rotate the motor is obtained by reading the vehicle's overall message.

3. The method according to claim 1, characterized in that, The process of supplying power to the motor a second time, controlling the motor to start from a standstill, and gradually increasing the motor torque in increments of at least one torque value until reaching the initial torque at the gear engagement point and the target required torque, thereby completing the calibration of the first-stage curve, includes: The second power supply is provided to the motor; Starting from the stationary state, the motor is controlled to gradually increase its torque to the initial torque of the tooth engagement step by step, starting with a first torque value; The torque of the motor is controlled to gradually increase from the initial torque of the toothed motor to the target required torque by increasing the step size by at least one torque value, thereby completing the calibration of the first stage curve, wherein each of the increasing step sizes increases sequentially.

4. The method according to claim 3, characterized in that, The step of increasing the motor torque by at least one torque value in increments, starting from the initial torque of the toothed section and gradually increasing it to the target required torque, thereby completing the calibration of the first stage curve, includes: The second torque value is used to increase the step size, and the torque of the motor is controlled to increase continuously from the initial torque of the tooth according to a preset cycle for a first time length. After the torque of the motor continues to increase for the first time length, the torque of the motor continues to increase for the second time length according to the preset period by increasing the step size by the third torque value, wherein the third torque value is greater than the second torque value; After the torque of the motor continues to increase for the second time length, the torque is increased by a fourth torque value in increments, and the torque of the motor continues to increase for a third time length according to the preset cycle. This process is repeated until the torque of the motor increases to the target required torque, thereby completing the calibration of the first stage curve. The fourth torque value is greater than the third torque value.

5. The method according to claim 4, characterized in that, The method further includes: During the first time period during which the torque of the motor continues to increase: the driving tooth and the driven tooth engage.

6. The method according to claim 1, characterized in that, The process of stopping the second power supply to the motor, controlling the motor to gradually reduce its torque from the target required torque by at least one torque value in decreasing steps until the gear termination torque is reached, thereby completing the calibration of the first segment of the second-stage curve, includes: Stop supplying power to the motor for the second time; Using the fifth torque value as the decreasing step size, and according to a preset cycle, the torque of the motor is controlled to continuously decrease from the target required torque for a fourth time period. After the torque of the motor continues to decrease for the fourth time length, the torque of the motor continues to decrease for the fifth time length according to the preset period, with a sixth torque value as the reduction step, wherein the sixth torque value is less than the fifth torque value; After the torque of the motor continues to decrease for the fifth time length, the torque of the motor continues to decrease for the sixth time length according to the preset cycle, with the seventh torque value as the reduction step. This continues until the torque of the motor decreases to the tooth-stopping torque, thereby completing the calibration of the first segment of the second stage curve. The seventh torque value is less than the sixth torque value.

7. The method according to claim 1, characterized in that, The control of the motor, starting from reducing to zero torque, gradually reduces the motor torque to negative torque by decreasing the step size by at least one torque value, thereby completing the calibration of the third-stage curve, including: Starting from the point where the motor torque is reduced to zero, the torque of the motor is gradually reduced to the negative torque by at least one torque value as a decreasing step, thereby completing the calibration of the third stage curve. The decreasing step values ​​increase sequentially. During the period when the motor torque is gradually reduced to the negative torque, the driving tooth and the driven tooth engage.

8. The method according to claim 7, characterized in that, Starting from the point where the motor torque is reduced to zero, the torque of the motor is gradually reduced to the negative torque by decreasing the step size by at least one torque value, thereby completing the calibration of the third-stage curve, including: Starting from the point where the motor torque decreases to zero, the torque of the motor is controlled to decrease continuously for a seventh time period, with the eighth torque value as the decreasing step size, according to a preset cycle. After the torque of the motor continues to decrease for the seventh time length, the torque of the motor continues to decrease for the eighth time length according to the preset period, with the ninth torque value as the decrease step. The ninth torque value is greater than the eighth torque value. After the torque of the motor continues to decrease for the eighth time length, the torque of the motor continues to decrease for the ninth time length according to the preset cycle, with the tenth torque value as the reduction step. This process is repeated until the torque of the motor is reduced to a preset negative torque, thereby completing the calibration of the third stage curve. The tenth torque value is greater than the ninth torque value.

9. The method according to claim 1, characterized in that, The third power supply to the motor, controlling the motor to gradually increase its torque from the negative torque stage to the zero torque stage by increments of at least one torque value, thereby completing the calibration of the fourth-stage curve, includes: The motor is supplied with power for the third time. Starting from the negative torque, the torque of the motor is gradually increased to the zero torque by increasing the step size by at least one torque value, thereby completing the calibration of the fourth stage curve. The step sizes decrease sequentially between each other.

10. The method according to claim 9, characterized in that, The third power supply to the motor, starting from the negative torque, gradually increases the motor torque to zero torque by incrementing by at least one torque value, thereby completing the calibration of the fourth-stage curve, includes: The third power supply is then provided to the motor; Starting from the negative torque, the torque of the motor is controlled to increase by a step size of eleventh torque value according to a preset cycle, starting from the negative torque and continuously increasing for tenth time length. After the torque of the motor continues to increase for the tenth time length, the torque of the motor continues to increase for the eleventh time length according to the preset period, with the twelfth torque value being less than the eleventh torque value. After the torque of the motor continues to increase for the eleventh time length, the step size is increased by the thirteenth torque value. According to the preset cycle, the torque of the motor is controlled to continue to increase for the twelfth time length, and so on, until the torque of the motor increases to the zero torque, thereby completing the calibration of the fourth stage curve, wherein the thirteenth torque value is less than the twelfth torque value.

11. The method according to claim 1, characterized in that, The step of obtaining the torque curve based on the first stage curve, the second stage curve, the third stage curve, and the fourth stage curve includes: The first stage curve and the second stage curve are merged and spliced ​​together end to end; The second-stage curve is merged and spliced ​​with the third-stage curve; The third-stage curve and the fourth-stage curve are merged and spliced ​​together to obtain the torque curve.

12. The method according to any one of claims 1-11, characterized in that, The process of obtaining the corresponding active damping compensation torque based on the motor's rotational speed vibration frequency at the current moment includes: Based on a bandpass filter, the rotational vibration frequency of the motor at the current moment is filtered to extract the corresponding rotational vibration signal; Based on the PI controller, the active damping compensation torque output by the PI controller is obtained by using the rotational speed vibration signal and the given value of the PI controller.

13. The method according to claim 12, characterized in that, The step of filtering the motor's rotational speed vibration frequency at the current moment based on a bandpass filter to extract the corresponding rotational speed vibration signal includes: The high-frequency band of the rotational vibration frequency is filtered out by a bandpass filter, and the low-frequency band of the rotational vibration frequency is filtered out by a bandpass filter, thereby extracting the rotational vibration signal. The frequencies of the high-frequency band are all higher than the preset high cutoff frequency of the bandpass filter, and the frequencies of the low-frequency band are all lower than the preset low cutoff frequency of the bandpass filter.

14. The method according to claim 12, characterized in that, After calculating the active damping compensation torque output by the PI controller using the rotational speed vibration signal and the setpoint of the PI controller, the method further includes: The active damping compensation torque output by the PI controller is limited to obtain the limited active damping compensation torque.

15. The method according to any one of claims 1-11, characterized in that, The step of superimposing the active damping compensation torque with a corresponding pre-calibrated torque to obtain the control torque includes: The control torque is obtained by adding the active damping compensation torque to the corresponding pre-calibrated torque.

16. The method according to any one of claims 1-11, characterized in that, The step of controlling the active tooth driven by the motor to mesh with the corresponding driven tooth based on the control torque includes: Based on the control torque, the corresponding pre-calibrated table is consulted to obtain the corresponding motor DQ axis current; The motor is controlled based on the DQ axis current of the motor, so that the driving tooth and the driven tooth mesh together.

17. The method according to claim 16, characterized in that, The step of querying a pre-calibrated table based on the control torque to obtain the corresponding motor DQ axis current includes: If the control torque is within the preset small torque range, the corresponding pre-calibrated first table is consulted to obtain the corresponding motor DQ axis current. The lookup torque step size of the first table is N times the normal torque step size, which is equal to M times the maximum peak torque of the motor. Both N and M are greater than 0 and less than 1.

18. The method according to claim 16, characterized in that, The step of querying a pre-calibrated table based on the control torque to obtain the corresponding motor DQ axis current includes: If the control torque is outside the preset small torque range, the corresponding pre-calibrated second table is consulted to obtain the corresponding motor DQ axis current. The lookup torque step size of the second table is the normal torque step size, which is equal to M times the maximum peak torque of the motor, where M is greater than 0 and less than 1.

19. A gear backlash engagement torque control system, characterized in that, include: Motor, compensation torque calculation node, torque superposition node, and variable PI control current loop; The motor is connected to the compensation torque calculation node, the compensation torque calculation node is connected to the torque superposition node, and the torque superposition node is connected to the variable PI control current loop; The compensation torque calculation node is used to obtain the corresponding active damping compensation torque based on the motor's rotational speed at the current moment. The torque superposition node is used to superimpose the active damping compensation torque with the corresponding pre-calibrated torque to obtain the control torque, wherein the pre-calibrated torque is the torque value corresponding to the current moment in the torque curve obtained by pre-calibrating the whole vehicle. The variable PI control current loop is used to control the active tooth driven by the motor to mesh with the corresponding driven tooth based on the control torque; The torque superposition node is specifically used for: The motor is powered on for the first time to obtain the minimum torque that makes the motor rotate; A second power supply is supplied to the motor, and the motor is controlled to start from a stationary state and gradually increase the torque of the motor by increasing the step size by at least one torque value until the initial torque of tooth engagement and the target required torque are reached, thereby completing the calibration of the first stage curve. The initial torque of tooth engagement is equal to the minimum torque, and the target required torque is greater than the minimum torque. Stop supplying power to the motor for the second time, and control the motor to gradually reduce the torque of the motor from the target required torque by a decreasing step size of at least one torque value until the tooth-stopping torque is reached, thereby completing the calibration of the first part of the second stage curve, wherein the tooth-stopping torque is equal to the minimum torque; The motor is controlled to gradually reduce its torque to zero starting from the point where the tooth ends, with a preset torque value decreasing in step size, thereby completing the calibration of the latter part of the second stage curve; Starting from the point where the torque of the motor decreases to zero, the torque of the motor is gradually reduced to negative torque by decreasing the step size by at least one torque value, thereby completing the calibration of the third-stage curve; The motor is powered on for the third time, and the motor is controlled to gradually increase its torque to zero torque, starting from the negative torque and increasing the torque step by at least one torque value, thereby completing the calibration of the fourth stage curve. The torque curve is obtained based on the first stage curve, the second stage curve, the third stage curve, and the fourth stage curve.

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