Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system configurations, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
As new energy automobile technologies continue to innovate and advance, fully utilizing the extreme drivability of these vehicles becomes increasingly critical. In an actual driving process, the friction coefficient between the vehicle tire and the road surface is reduced due to wet road surface, ice, sand and the like, so that the stability of the vehicle when passing through the road surface with low adhesive force is reduced, and the driving safety is affected.
The conventional solutions rely mainly on hardware devices to cope with the safety problems of low adhesion road running, such as by installing tires with a high friction coefficient, replacing winter tires in rainy and snowy days, using snow chains, etc. These devices help the vehicle to stably travel on a low adhesion road surface by increasing the coefficient of friction between the tire and the road surface. However, the effect of these hardware auxiliary means for the conventional automobiles in the new energy automobiles is not ideal, and the requirements of stability and safety of the new energy automobiles running on the low-adhesion road surface cannot be completely satisfied. Therefore, how to design a stability control scheme for a new energy automobile to solve the problem of reduced running stability of the vehicle under the low-adhesion road surface has become an urgent problem to be solved.
In view of the problems existing in the prior art, the application aims to provide an automobile stability control method based on slip rate, which is characterized in that through monitoring real-time motion parameters of an automobile, the application calculates the conversion wheel speed of each wheel, calculates the actual slip rate of the shaft end based on the conversion wheel speed and the sensor wheel speed, and re-corrects the original target slip rate of the shaft end by utilizing the correction coefficient of the target slip rate of the shaft end to obtain the corrected target slip rate of the shaft end; determining a shaft end torque correction value by utilizing the shaft end actual slip rate and the shaft end target slip rate, and re-correcting the shaft end torque original correction offset value by utilizing a shaft end torque correction offset value correction coefficient to obtain a corrected shaft end torque correction offset value; and determining a shaft end torque correction gradient based on the difference between the final shaft end target torque and the shaft end actual torque and the vehicle speed, and finally, calculating the shaft end request torque of the current period based on the shaft end torque correction gradient and the shaft end request torque of the previous period. The real-time control of the axle end torque under the working condition of the low-adhesion road surface is realized by utilizing the axle end request torque in the current period, so that the stability of the vehicle on the low-adhesion road surface is ensured, and the driving safety of the vehicle is improved.
It should be noted that, the new energy automobile in the embodiment of the present application refers to an automobile that uses a new energy (non-traditional petroleum and diesel energy) and has an advanced technology. The automobiles adopt a novel power system, so that the automobile emission can be effectively reduced, the influence on the environment is reduced, and the energy utilization efficiency is improved. The new energy automobiles of the embodiments of the present application include, but are not limited to, the following types of automobiles: electric Vehicles (EVs), pure electric vehicles (BEVs), fuel Cell Electric Vehicles (FCEVs), plug-in hybrid electric vehicles (PHEVs), hybrid Electric Vehicles (HEVs), and the like.
The following describes the technical scheme of the present application in detail with reference to the accompanying drawings and specific embodiments.
Fig. 1 is a schematic flow chart of an automobile stability control method based on a slip ratio according to an embodiment of the present application. The slip ratio-based vehicle stability control method of fig. 1 may be performed by an overall vehicle controller of a new energy vehicle. As shown in fig. 1, the method for controlling the stability of the automobile based on the slip ratio specifically may include:
s101, acquiring the actual slip rate of the shaft end of the vehicle, and re-correcting the original target slip rate of the shaft end by utilizing the correction coefficient of the target slip rate of the shaft end to obtain the corrected target slip rate of the shaft end;
S102, determining a shaft end torque correction value based on the shaft end actual slip rate and the shaft end target slip rate, and carrying out re-correction on the shaft end torque original correction offset value by utilizing a shaft end torque correction offset value correction coefficient to obtain a corrected shaft end torque correction offset value;
s103, calculating final shaft end target torque based on the shaft end torque correction value, the shaft end torque correction offset value and the shaft end original target torque, and calculating a difference value between the final shaft end target torque and the shaft end actual torque;
and S104, determining a shaft end torque correction gradient based on the difference value between the final shaft end target torque and the shaft end actual torque and the vehicle speed, calculating the shaft end request torque of the current period based on the shaft end torque correction gradient and the shaft end request torque of the previous period, and transmitting the shaft end request torque of the current period to the driving motor to execute torque control.
Specifically, the embodiment of the application monitors real-time motion parameters of a vehicle by using the whole vehicle controller, performs table lookup by using steering wheel rotation angles in the real-time motion parameters to obtain wheel rotation angles, and calculates wheel speed change rates and wheel acceleration change rates corresponding to all wheels based on wheel speeds in the real-time motion parameters; and the corresponding conversion wheel speeds of the wheels are respectively calculated based on the speed, the yaw rate, the distance between the mass center and the front axle, the wheel distance of the front wheels and the wheel upper corners obtained by table lookup in the real-time motion parameters.
In the running process of the vehicle, the parameters of the whole vehicle and each wheel are monitored in real time by using the VCU (Vehicle Control Unit, vehicle controller) so as to obtain real-time motion parameters. Real-time kinematic parameters of a vehicle include, but are not limited to, the following: vehicle speed, wheel speed, yaw rate, steering wheel angle, vehicle requested torque, etc. Among them, the yaw rate is mainly used to describe the steering behavior of an automobile during running, and is generally expressed in degrees per second (degree/s) or radians per second (rad/s).
Further, the wheel-up turning angle (Wheel Steering Angle) refers to a turning angle of a wheel of an automobile with respect to a longitudinal axis of a vehicle body during turning, and can be divided into a front wheel turning angle and a rear wheel turning angle. In short, the angle of inclination of the wheels during steering. The parameter has important significance in the aspects of running stability, operability, turning radius and the like of the automobile. The wheel rotation angle in the embodiment of the application is a value obtained by querying a predetermined two-dimensional table with the steering wheel rotation angle as an abscissa (i.e., a horizontal axis).
In some embodiments, prior to obtaining the actual slip ratio of the axle end of the vehicle, the method of embodiments of the present application further comprises:
The method comprises the steps of monitoring real-time motion parameters of a vehicle, and calculating the converted wheel speed of each wheel according to the real-time motion parameters, wherein the real-time motion parameters comprise the wheel upper corner, the yaw rate, the distance between the mass center and a front axle, the wheel tread of the front wheel and the vehicle speed of each wheel.
In practical applications, the following formula may be used to calculate the converted wheel speed of each wheel:
;
;
;
;
wherein,,represents the converted wheel speed of the left front wheel, +.>Represents the converted wheel speed of the right front wheel, +.>Represents the converted wheel speed of the left rear wheel, +.>Represents the converted wheel speed of the right rear wheel, +.>Indicating the angle of rotation on the wheel->The yaw rate is indicated as such,representing the distance of the centroid from the front axis +.>Representing the wheel track of the front wheel,/->Indicating the vehicle speed.
Specifically, when the collected real-time motion parameters are used for calculating the converted wheel speed of each wheel, the wheel speed corresponding to each wheel is calculated according to the wheel rotation angle obtained by looking up a table (a preset two-dimensional table), and then the information such as the vehicle speed, the yaw rate, the distance between the centroid and the front axle, the wheel tread of the front wheel and the like is combined. Calculating the converted wheel speeds of the various wheels by using the real-time motion data of the vehicle can help the VCU to more accurately analyze the running state of the vehicle, thereby achieving more optimal control over the running process of the vehicle.
In some embodiments, obtaining an actual slip ratio of an axle end of a vehicle includes:
the method comprises the steps of obtaining the sensor wheel speed of each wheel, calculating the actual slip rate corresponding to each wheel by using the sensor wheel speed and the converted wheel speed, selecting the actual slip rate with larger value from the left front wheel actual slip rate and the right front wheel actual slip rate as the front axle actual slip rate, and selecting the actual slip rate with larger value from the left rear wheel actual slip rate and the right rear wheel actual slip rate as the rear axle actual slip rate.
Specifically, after the converted wheel speeds corresponding to the respective wheels are calculated, the actual slip rates corresponding to the respective wheels are calculated respectively in combination with the rotational speeds of the wheels (i.e., the sensor wheel speeds) monitored in real time by the wheel speed sensors (Wheel Speed Sensor). And the front axle actual slip ratio is set based on the left front wheel actual slip ratio and the right front wheel actual slip ratio, and the rear axle actual slip ratio is set based on the left rear wheel actual slip ratio and the right rear wheel actual slip ratio. In practical application, the front axle actual slip ratio and the rear axle actual slip ratio are collectively referred to as an axle end actual slip ratio.
The following formula is combined to describe a method for calculating the actual slip rate of the axle end, and in practical application, the following formula is adopted to calculate the actual slip rate corresponding to each wheel and the actual slip rate corresponding to the front axle and the rear axle respectively:
;
;
;
;
);
);
Wherein,,indicating the actual slip rate of the left front wheel, +.>Indicating the actual slip rate of the right front wheel, +.>Indicating the actual slip rate of the left rear wheel, +.>Indicating the actual slip rate of the right rear wheel, +.>Sensor wheel speed representing left front wheel, for example>Sensor wheel speed representing right front wheel, for example>Sensor wheel speed representing the left rear wheel, for example>Sensor wheel speed representing right rear wheel, for example>Front axle actual slip ratio->Indicating the actual slip ratio of the rear axle.
Specifically, the actual slip rate (Actual Slip Ratio) of the wheels can measure the adhesion condition of the wheels to the road surface in the driving process, and has important significance for evaluating the control performance, traction and safety of the automobile. The actual slip rate of each wheel is calculated according to the actual rotation speed (namely, the sensor wheel speed) of each wheel of the vehicle and the calculated conversion wheel speed.
Further, in the embodiment of the application, the front axle actual slip ratio with the larger value in the left front wheel actual slip ratio and the right front wheel actual slip ratio is used as the front axle actual slip ratio, and the rear axle actual slip ratio with the larger value in the left rear wheel actual slip ratio and the right rear wheel actual slip ratio is used as the rear axle actual slip ratio.
In some embodiments, the method for correcting the original target slip rate of the shaft end by using the correction coefficient of the target slip rate of the shaft end to obtain the corrected target slip rate of the shaft end comprises:
Inquiring a preset target slip rate mapping relation by using the current speed of the vehicle and the gradient of the road surface where the vehicle is located to obtain an original target slip rate of the shaft end;
inquiring a preset target slip rate correction coefficient mapping relation by utilizing the maximum wheel speed change rate of the shaft end to obtain a shaft end target slip rate correction coefficient;
and multiplying the original shaft end target slip rate by a shaft end target slip rate correction coefficient to obtain the corrected shaft end target slip rate.
Specifically, the original target slip rate of the shaft end is data recorded in a target slip rate table set by taking the vehicle speed as an abscissa and taking the gradient as an ordinate, and the preset target slip rate table is inquired by utilizing the current vehicle speed of the vehicle and the gradient of the road surface where the vehicle is located, so that the original target slip rate of the shaft end can be obtained.
Further, the shaft end target slip rate correction coefficient is data recorded in a target slip rate correction coefficient table which is set by taking the shaft end maximum wheel speed change rate as an abscissa and taking the shaft end target slip rate correction coefficient as an ordinate, and the shaft end target slip rate correction coefficient corresponding to the shaft end maximum wheel speed change rate can be obtained by inquiring the table by utilizing the shaft end maximum wheel speed change rate.
In some embodiments, the method of embodiments of the present application further comprises:
based on the slip rate characteristics and historical actual measurement data of the vehicle under different speeds and gradients, taking the maximum adhesive force as a set target to match the corresponding shaft end original target slip rate, and establishing a target slip rate mapping relation according to the speeds, the gradients and the shaft end original target slip rate;
based on preset road scenes, historical actual measurement data of the vehicle are obtained, the wheel speed change rate is counted, corresponding shaft end target slip rate correction coefficients are matched for different road scenes based on the shaft end maximum wheel speed change rate, and a target slip rate correction coefficient mapping relation is established according to the shaft end maximum wheel speed change rate and the shaft end target slip rate correction coefficients.
Specifically, the target slip rate mapping relationship and the target slip rate correction coefficient mapping relationship in the embodiment of the present application may be presented in a table form, and when presented in a table form, the target slip rate mapping relationship may be represented by a target slip rate table, and the target slip rate correction coefficient mapping relationship may be represented by a target slip rate correction coefficient table.
Further, in order to configure the target slip ratio table, the embodiment of the application performs real vehicle matching by taking the maximum adhesive force as a set target (namely, taking the maximum adhesive force as the set target to match the corresponding shaft end original target slip ratio) by counting the rules of the vehicle under different speeds and slopes based on the slip ratio characteristics and the historical actual measurement data of the vehicle under different speeds and slopes. The target slip rate table can be obtained by establishing a target slip rate mapping relation among the vehicle speed, the gradient and the original target slip rate of the shaft end and presenting the target slip rate mapping relation in a table form.
Similarly, in order to configure the target slip rate correction coefficient table, the embodiment of the application performs real vehicle matching by setting the axle end target slip rate correction coefficient based on different road scenes and real vehicle test data and by counting the wheel speed change rate, and distinguishing different road conditions (namely, matching corresponding axle end target slip rate correction coefficients for different road scenes based on the axle end maximum wheel speed change rate). The target slip rate correction coefficient table can be obtained by establishing a target slip rate correction coefficient mapping relation between the maximum wheel speed change rate of the shaft end and the target slip rate correction coefficient of the shaft end and presenting the target slip rate correction coefficient mapping relation in a table form.
In practical application, after the original target slip rate of the shaft end and the correction coefficient of the target slip rate of the shaft end are obtained through the table lookup, the following formula can be used for calculating the target slip rate of the shaft end, and the specific calculation formula is as follows:
;
wherein,,indicating shaft end target slip ratio->The original target slip rate at the shaft end is indicated,indicating the target slip rate correction coefficient of the shaft end.
In some embodiments, determining the shaft end torque correction value based on the shaft end actual slip rate and the shaft end target slip rate includes:
Calculating a slip rate difference value and a slip rate difference value change rate by utilizing the actual slip rate of the shaft end and the target slip rate of the shaft end, inquiring a preset shaft end torque correction mapping relation by taking the slip rate difference value as a horizontal axis and the slip rate difference value change rate as a vertical axis to obtain a shaft end torque correction value.
Specifically, after the actual slip rate of the shaft end and the target slip rate of the shaft end are calculated respectively, a slip rate difference value and a slip rate difference change rate are calculated based on the target slip rate of the shaft end and the actual slip rate of the shaft end, and after the slip rate difference value and the slip rate difference change rate are obtained, a preset shaft end torque correction value table is inquired by taking the slip rate difference value as an abscissa and the slip rate difference change rate as an ordinate to obtain a shaft end torque correction value. The shaft end torque correction value table is used for representing preset values of shaft end torque correction values along with the slip rate difference value and the change rate of the slip rate difference value.
In some embodiments, the method of embodiments of the present application further comprises:
based on a preset road scene, acquiring historical actual measurement data of a vehicle, setting corresponding axle end torque correction values according to a preset configuration rule of the axle end torque correction values, and establishing an axle end torque correction mapping relation among a slip rate difference value, a slip rate difference value change rate and the axle end torque correction values;
The configuration rules of the shaft end torque correction value comprise rules set by taking the minimum adjustment torque of the offset value for realizing the actual slip rate and the target slip rate as a target.
Specifically, the axial end torque correction map of the embodiment of the present application may be presented in the form of a table, and when presented in the form of a table, the axial end torque correction map may be presented in the form of an axial end torque correction value table.
Further, in order to configure the axle end torque correction value table, the embodiment of the application performs real vehicle matching (that is, sets a corresponding axle end torque correction value according to the configuration rule of the axle end torque correction value) by counting the slip rate difference value and the slip rate difference value change rate and taking the degree of inhibiting the deviation of the actual slip rate from the target slip rate and the trend adjustment torque as targets based on different road scenes and real vehicle test data. The axle end torque correction value table can be obtained by establishing an axle end torque correction mapping relation among the slip rate difference value, the slip rate difference value change rate and the axle end torque correction value and presenting the axle end torque correction mapping relation in a table form.
In some embodiments, re-correcting the shaft end torque raw correction offset value using a shaft end torque correction offset value correction factor to obtain a corrected shaft end torque correction offset value, comprising:
Taking the actual slip rate of the shaft end as a horizontal axis, taking the change rate of the actual slip rate of the shaft end as a vertical axis, and inquiring the mapping relation of the preset original correction offset value to obtain the original correction offset value of the shaft end torque;
taking the maximum wheel acceleration change rate of the shaft end as a transverse axis, and inquiring the mapping relation of the preset torque correction offset value correction coefficient to obtain a shaft end torque correction offset value correction coefficient;
and multiplying the original corrected offset value of the shaft end torque by a correction coefficient of the corrected offset value of the shaft end torque to obtain the corrected offset value of the shaft end torque.
Specifically, in the embodiment of the application, the axle end torque correction offset value is calculated based on the axle end maximum wheel acceleration change rate, the axle end actual slip rate and the axle end actual slip rate change rate, firstly, the axle end actual slip rate is taken as an abscissa, the axle end actual slip rate change rate is taken as an ordinate, and a preset original correction offset value table is inquired to obtain an axle end torque original correction offset value; and secondly, inquiring a preset torque correction offset value correction coefficient table by taking the maximum wheel acceleration change rate of the shaft end as an abscissa to obtain the shaft end torque correction offset value correction coefficient. The original correction offset value table is used for representing a preset value of the change of the original correction offset value of the shaft end torque along with the actual slip rate of the shaft end and the change rate of the actual slip rate of the shaft end, and the torque correction offset value correction coefficient table is used for representing a preset value of the change of the correction coefficient of the shaft end torque correction offset value along with the maximum wheel acceleration change rate of the shaft end.
In some embodiments, the method of embodiments of the present application further comprises:
based on a preset road scene, acquiring historical actual measurement data of a vehicle, setting a corresponding original correction offset value of the shaft end torque according to a configuration rule of a preset original correction offset value, and establishing an original correction offset value mapping relation among the actual slip rate of the shaft end, the change rate of the actual slip rate of the shaft end and the original correction offset value of the shaft end torque;
based on a preset road scene, acquiring historical actual measurement data of a vehicle, setting a corresponding axle end torque correction offset value correction coefficient according to a configuration rule of a preset torque correction offset value correction coefficient, and establishing a torque correction offset value correction coefficient mapping relation between an axle end maximum wheel acceleration change rate and the axle end torque correction offset value correction coefficient;
the configuration rules of the original correction offset value comprise rules set for realizing that the actual slip rate value is smaller than a preset slip rate threshold value and inhibiting the continuous increase of the actual slip rate value to be a target; the arrangement rules of the torque correction offset value correction coefficient include rules set for the purpose of suppressing the continuous increase of the maximum wheel acceleration.
Specifically, the original correction offset value mapping relationship and the torque correction offset value correction coefficient mapping relationship in the embodiment of the present application may be represented in a table form, and when the original correction offset value mapping relationship is represented in a table form, the original correction offset value mapping relationship may be represented by an original correction offset value table, and the torque correction offset value correction coefficient mapping relationship may be represented by a torque correction offset value correction coefficient table.
Further, in order to configure the original correction offset value table, the embodiment of the application performs real vehicle matching by counting the actual slip rate of the shaft end and the change rate of the actual slip rate of the shaft end based on different road scenes and real vehicle test data so as to inhibit the actual slip rate from being large and continuously increasing as a target, and adjusts the torque (namely, sets the corresponding original correction offset value of the shaft end torque according to the configuration rule of the original correction offset value). The original correction offset value table can be obtained by establishing an original correction offset value mapping relation among the actual slip rate of the shaft end, the change rate of the actual slip rate of the shaft end and the original correction offset value of the shaft end torque and presenting the original correction offset value mapping relation in a table form.
Similarly, in order to configure the torque correction offset value correction coefficient table, the embodiment of the application performs real vehicle matching by counting the maximum wheel acceleration change rate at the axle end based on different road scenes and real vehicle test data so as to inhibit the continuous increase of the maximum wheel acceleration to be the target adjustment torque (namely, setting the corresponding axle end torque correction offset value correction coefficient according to the configuration rule of the torque correction offset value correction coefficient). The torque correction offset value correction coefficient table can be obtained by establishing a torque correction offset value correction coefficient mapping relation between the maximum wheel acceleration change rate of the shaft end and the torque correction offset value correction coefficient of the shaft end and presenting the torque correction offset value correction coefficient mapping relation in a table form.
In practical application, after the original correction offset value of the shaft end torque and the correction coefficient of the shaft end torque correction offset value are obtained through the table lookup, the shaft end torque correction offset value can be calculated by using the following formula, and the specific calculation formula is as follows:
;
wherein,,representing the axle end torque correction offset value,/->Represents the original corrected offset value of the shaft end torque, +.>Representing the shaft end torque correction offset value correction factor.
Further, a final shaft end target torque is calculated based on the shaft end original target torque, the shaft end torque correction value, and the shaft end torque correction offset value. In practical applications, the final shaft end target torque can be calculated using the following formula:
;
wherein,,representing the final shaft end target torque +.>Representing the original target torque at the shaft end +.>Indicating the axle end torque correction value,/, and%>Representing the shaft end torque correction offset value.
Further, after the final shaft end target torque is obtained through calculation, calculating a difference value between the final shaft end target torque and the shaft end actual torque; and calculating an axle end torque correction gradient based on the difference value between the final axle end target torque and the axle end actual torque and the vehicle speed, and in the actual application, inquiring a preset axle end torque correction gradient table by taking the difference value between the final axle end target torque and the axle end actual torque as an abscissa and taking the current vehicle speed of the vehicle as an ordinate to obtain the axle end torque correction gradient. The shaft end torque correction gradient table is used for representing a preset value of the shaft end torque correction gradient along with the difference value between the final shaft end target torque and the shaft end actual torque and the change of the vehicle speed.
In some embodiments, determining the shaft end torque correction gradient based on the difference between the final shaft end target torque and the shaft end actual torque and the vehicle speed includes:
and inquiring a preset shaft end torque correction gradient mapping relation by taking the difference value between the final shaft end target torque and the shaft end actual torque as a horizontal axis and the vehicle speed as a vertical axis to obtain a shaft end torque correction gradient.
Specifically, the axle end torque correction gradient is data recorded in an axle end torque correction gradient table set by taking the difference between the final axle end target torque and the axle end actual torque as an abscissa and taking the vehicle speed as an ordinate, and the preset axle end torque correction gradient table is queried by utilizing the difference between the final axle end target torque and the axle end actual torque and the current vehicle speed of the vehicle, so that the axle end torque correction gradient can be obtained.
In some embodiments, the method of embodiments of the present application further comprises:
setting corresponding shaft end torque correction gradients according to preset configuration rules of the shaft end torque correction gradients based on different vehicle speed conditions, and establishing a shaft end torque correction gradient mapping relation between a difference value between final shaft end target torque and shaft end actual torque, vehicle speed and the shaft end torque correction gradients;
The configuration rules of the shaft end torque correction gradient comprise rules which are set by taking the difference between the final shaft end target torque and the shaft end actual torque as a target along with the change of the shaft end torque correction gradient.
Specifically, the axial end torque correction gradient map of the embodiment of the present application may be presented in the form of a table, and when presented in the form of a table, the axial end torque correction gradient map may be presented in the form of an axial end torque correction gradient table.
Further, in order to configure the shaft end torque correction gradient table, the embodiment of the application calculates the difference value between the final shaft end target torque and the shaft end actual torque under different vehicle speeds and the vehicle speed, takes the large torque difference value fast gradient as a trend, takes the dynamic response as a priority, and gives consideration to the dynamic smoothness to perform real vehicle matching (namely, sets the corresponding shaft end torque correction gradient according to the configuration rule of the shaft end torque correction gradient). The shaft end torque correction gradient table can be obtained by establishing a shaft end torque correction gradient mapping relation among the difference value between the final shaft end target torque and the shaft end actual torque, the vehicle speed and the shaft end torque correction gradient and presenting the shaft end torque correction gradient mapping relation in a table form.
Further, after the shaft end torque correction gradient is obtained through the table lookup, the shaft end request torque of the current period is calculated based on the shaft end torque correction gradient and the shaft end request torque of the previous period, that is, the shaft end request torque is calculated by using the shaft end torque correction gradient. In practical application, the axle end request torque of the current period can be calculated by adopting the following formula:
;
wherein,,shaft end request torque representing current period, +.>Shaft end request torque indicating previous period, +.>Representing the shaft end torque correction gradient.
According to the technical scheme provided by the embodiment of the application, in order to improve the stability of the low-traction surface of the whole vehicle, the embodiment of the application calculates the conversion wheel speed based on the vehicle speed, the yaw rate and the steering wheel rotation angle, calculates the actual slip rate based on the conversion wheel speed and the sensor wheel speed, calculates the target slip rate based on the mode, the vehicle speed and the gradient, calculates the torque correction value based on the slip rate difference value, the change rate, the slip rate and the change rate, and the wheel speed change rate, calculates the torque correction gradient based on the torque difference and the vehicle speed, and ensures the accuracy of the vehicle under different working conditions, thereby being convenient for the estimation of other basic parameters of the whole vehicle and the development of related functions. The vehicle driving safety control method and device guarantee stability of the vehicle when the vehicle runs on a low-adhesion road surface, improve safety of vehicle driving and provide high-quality driving experience for a driver.
The following are device embodiments of the present application, which may be used to perform method embodiments of the present application. For details not disclosed in the device embodiments of the present application, please refer to the method embodiments of the present application.
Fig. 2 is a schematic structural diagram of an automobile stability control device based on a slip ratio according to an embodiment of the present application. As shown in fig. 2, the slip ratio-based vehicle stability control apparatus includes:
the obtaining module 201 is configured to obtain an actual slip rate of an axle end of the vehicle, and correct the original target slip rate of the axle end again by using an axle end target slip rate correction coefficient to obtain a corrected axle end target slip rate;
the correction module 202 is configured to determine a shaft end torque correction value based on the shaft end actual slip rate and the shaft end target slip rate, and correct the shaft end torque original correction offset value again by using the shaft end torque correction offset value correction coefficient to obtain a corrected shaft end torque correction offset value;
a calculation module 203 configured to calculate a final shaft end target torque based on the shaft end torque correction value, the shaft end torque correction offset value, and the shaft end original target torque, and calculate a difference between the final shaft end target torque and the shaft end actual torque;
The control module 204 is configured to determine an axle end torque correction gradient based on a difference between the final axle end target torque and the axle end actual torque and the vehicle speed, calculate an axle end request torque of a current period based on the axle end torque correction gradient and an axle end request torque of a previous period, and transmit the axle end request torque of the current period to the drive motor to perform torque control.
In some embodiments, the acquisition module 201 of fig. 2 acquires the sensor wheel speed of each wheel, calculates the actual slip rate corresponding to each wheel by using the sensor wheel speed and the converted wheel speed, and selects the actual slip rate with a larger value from the actual slip rate of the left front wheel and the actual slip rate of the right front wheel as the actual slip rate of the front axle, and selects the actual slip rate with a larger value from the actual slip rate of the left rear wheel and the actual slip rate of the right rear wheel as the actual slip rate of the rear axle.
In some embodiments, the obtaining module 201 of fig. 2 queries the predetermined target slip ratio mapping relationship by using the current speed of the vehicle and the gradient of the road surface on which the vehicle is located, to obtain the original target slip ratio of the shaft end; inquiring a preset target slip rate correction coefficient mapping relation by utilizing the maximum wheel speed change rate of the shaft end to obtain a shaft end target slip rate correction coefficient; and multiplying the original shaft end target slip rate by a shaft end target slip rate correction coefficient to obtain the corrected shaft end target slip rate.
In some embodiments, the acquisition module 201 of fig. 2 establishes the target slip ratio mapping relationship according to the vehicle speed, the gradient and the shaft end original target slip ratio by matching the corresponding shaft end original target slip ratio with the maximum adhesion as the setting target based on the slip ratio characteristics and the historical actual measurement data of the vehicle at different vehicle speeds and gradients; based on preset road scenes, historical actual measurement data of the vehicle are obtained, the wheel speed change rate is counted, corresponding shaft end target slip rate correction coefficients are matched for different road scenes based on the shaft end maximum wheel speed change rate, and a target slip rate correction coefficient mapping relation is established according to the shaft end maximum wheel speed change rate and the shaft end target slip rate correction coefficients.
In some embodiments, the correction module 202 of fig. 2 calculates the slip rate difference and the slip rate difference change rate using the actual slip rate of the shaft end and the target slip rate of the shaft end, and queries a predetermined shaft end torque correction map using the slip rate difference as the horizontal axis and the slip rate difference change rate as the vertical axis to obtain the shaft end torque correction value.
In some embodiments, the correction module 202 of fig. 2 obtains historical measured data of the vehicle based on a preset road scene, sets a corresponding axle end torque correction value according to a configuration rule of a predetermined axle end torque correction value, and establishes an axle end torque correction mapping relationship among a slip rate difference value, a slip rate difference value change rate, and the axle end torque correction value; the configuration rules of the shaft end torque correction value comprise rules set by taking the minimum adjustment torque of the offset value for realizing the actual slip rate and the target slip rate as a target.
In some embodiments, the correction module 202 of fig. 2 queries a predetermined original correction offset value mapping relationship with the actual slip rate of the shaft end as the horizontal axis and the actual slip rate change rate of the shaft end as the vertical axis to obtain an original correction offset value of the shaft end torque; taking the maximum wheel acceleration change rate of the shaft end as a transverse axis, and inquiring the mapping relation of the preset torque correction offset value correction coefficient to obtain a shaft end torque correction offset value correction coefficient; and multiplying the original corrected offset value of the shaft end torque by a correction coefficient of the corrected offset value of the shaft end torque to obtain the corrected offset value of the shaft end torque.
In some embodiments, the correction module 202 of fig. 2 obtains historical actual measurement data of the vehicle based on a preset road scene, sets a corresponding original correction offset value of the shaft end torque according to a configuration rule of a predetermined original correction offset value, and establishes an original correction offset value mapping relationship among the actual slip rate of the shaft end, the actual slip rate change rate of the shaft end, and the original correction offset value of the shaft end torque; based on a preset road scene, acquiring historical actual measurement data of a vehicle, setting a corresponding axle end torque correction offset value correction coefficient according to a configuration rule of a preset torque correction offset value correction coefficient, and establishing a torque correction offset value correction coefficient mapping relation between an axle end maximum wheel acceleration change rate and the axle end torque correction offset value correction coefficient; the configuration rules of the original correction offset value comprise rules set for realizing that the actual slip rate value is smaller than a preset slip rate threshold value and inhibiting the continuous increase of the actual slip rate value to be a target; the arrangement rules of the torque correction offset value correction coefficient include rules set for the purpose of suppressing the continuous increase of the maximum wheel acceleration.
In some embodiments, the control module 204 of FIG. 2 queries a predetermined shaft-end torque correction gradient map with the difference between the final shaft-end target torque and the shaft-end actual torque as the horizontal axis and the vehicle speed as the vertical axis to obtain a shaft-end torque correction gradient.
In some embodiments, the control module 204 of fig. 2 sets the corresponding axle-end torque correction gradient according to a predetermined configuration rule of the axle-end torque correction gradient based on different vehicle speed conditions, and establishes an axle-end torque correction gradient mapping relationship between the difference between the final axle-end target torque and the axle-end actual torque, the vehicle speed, and the axle-end torque correction gradient; the configuration rules of the shaft end torque correction gradient comprise rules which are set by taking the difference between the final shaft end target torque and the shaft end actual torque as a target along with the change of the shaft end torque correction gradient.
It should be understood that the sequence number of each step in the foregoing embodiment does not mean that the execution sequence of each process should be determined by the function and the internal logic of each process, and should not limit the implementation process of the embodiment of the present application in any way.
The embodiment of the application also provides a new energy automobile, which comprises an entire automobile controller, a motor controller, a driving motor and a transmission system; the whole vehicle controller is used for realizing the step of the shaft end target torque control method under the escaping mode so as to send the shaft end target torque to the motor controller; the motor controller is used for controlling the torque of the driving motor through the transmission system according to the shaft end target torque.
Fig. 3 is a schematic structural diagram of the electronic device 3 provided in the embodiment of the present application. As shown in fig. 3, the electronic apparatus 3 of this embodiment includes: a processor 301, a memory 302 and a computer program 303 stored in the memory 302 and executable on the processor 301. The steps of the various method embodiments described above are implemented when the processor 301 executes the computer program 303. Alternatively, the processor 301, when executing the computer program 303, performs the functions of the modules/units in the above-described apparatus embodiments.
Illustratively, the computer program 303 may be partitioned into one or more modules/units, which are stored in the memory 302 and executed by the processor 301 to complete the present application. One or more of the modules/units may be a series of computer program instruction segments capable of performing a specific function for describing the execution of the computer program 303 in the electronic device 3.
The electronic device 3 may be an electronic device such as a desktop computer, a notebook computer, a palm computer, or a cloud server. The electronic device 3 may include, but is not limited to, a processor 301 and a memory 302. It will be appreciated by those skilled in the art that fig. 3 is merely an example of the electronic device 3 and does not constitute a limitation of the electronic device 3, and may include more or fewer components than shown, or may combine certain components, or different components, e.g., the electronic device may also include an input-output device, a network access device, a bus, etc.
The processor 301 may be a central processing unit (Central Processing Unit, CPU) or other general purpose processor, digital signal processor (Digital Signal Processor, DSP), application specific integrated circuit (Application SpecificIntegrated Circuit, ASIC), field programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory 302 may be an internal storage unit of the electronic device 3, for example, a hard disk or a memory of the electronic device 3. The memory 302 may also be an external storage device of the electronic device 3, for example, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card) or the like, which are provided on the electronic device 3. Further, the memory 302 may also include both an internal storage unit and an external storage device of the electronic device 3. The memory 302 is used to store computer programs and other programs and data required by the electronic device. The memory 302 may also be used to temporarily store data that has been output or is to be output.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions. The functional units and modules in the embodiment may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit, where the integrated units may be implemented in a form of hardware or a form of a software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working process of the units and modules in the above system may refer to the corresponding process in the foregoing method embodiment, which is not described herein again.
In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
In the embodiments provided in this application, it should be understood that the disclosed apparatus/computer device and method may be implemented in other ways. For example, the apparatus/computer device embodiments described above are merely illustrative, e.g., the division of modules or elements is merely a logical functional division, and there may be additional divisions of actual implementations, multiple elements or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection via interfaces, devices or units, which may be in electrical, mechanical or other forms.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
The integrated modules/units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the present application implements all or part of the flow in the methods of the above embodiments, or may be implemented by a computer program to instruct related hardware, and the computer program may be stored in a computer readable storage medium, where the computer program may implement the steps of the respective method embodiments described above when executed by a processor. The computer program may comprise computer program code, which may be in source code form, object code form, executable file or in some intermediate form, etc. The computer readable medium may include: any entity or device capable of carrying computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer Memory, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), an electrical carrier signal, a telecommunications signal, a software distribution medium, and so forth. It should be noted that the content of the computer readable medium can be appropriately increased or decreased according to the requirements of the jurisdiction's jurisdiction and the patent practice, for example, in some jurisdictions, the computer readable medium does not include electrical carrier signals and telecommunication signals according to the jurisdiction and the patent practice.
The above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.