CN112109557B - Method and system for controlling rotating speed of driving wheel - Google Patents
Method and system for controlling rotating speed of driving wheel Download PDFInfo
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- CN112109557B CN112109557B CN201910538042.3A CN201910538042A CN112109557B CN 112109557 B CN112109557 B CN 112109557B CN 201910538042 A CN201910538042 A CN 201910538042A CN 112109557 B CN112109557 B CN 112109557B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
- B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L2240/00—Control parameters of input or output; Target parameters
- B60L2240/40—Drive Train control parameters
- B60L2240/46—Drive Train control parameters related to wheels
- B60L2240/461—Speed
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/72—Electric energy management in electromobility
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Abstract
The invention relates to the technical field of vehicle control, and provides a driving wheel rotating speed control method and a system thereof, wherein the driving wheel rotating speed control method comprises the following steps: judging whether the current vehicle condition meets a preset wheel speed control condition, and executing the following steps under the condition that the judgment result is yes: the method comprises the steps of obtaining the current rotating speed difference of two driving wheels connected to the same differential mechanism of a vehicle in real time, and controlling the torque value output by the vehicle to be reduced under the condition that the current rotating speed difference is larger than a preset first threshold value; controlling a rotational speed of a drive wheel of the vehicle based on the reduced torque value. The invention prevents damage and ablation of the differential.
Description
Technical Field
The invention relates to the technical field of vehicle control, in particular to a method and a system for controlling the rotating speed of a driving wheel.
Background
When the existing vehicle runs on an extreme road surface with low adhesive force, and the adhesive force on one side of the vehicle is too small, once the situation that the driving force generated by the motor controller for controlling the driving motor is larger than the friction force between the tire and the ground occurs, the tire on one side can slip. At this point, if the driver torque request is large, the rotational speed differential between the two drive wheels can easily exceed the maximum rotational speed differential between the two drive wheels that the differential can withstand, eventually resulting in damage and ablation of the differential.
The inventor of the present application finds, in the course of implementing the present invention, that there is no solution to the above-mentioned problems in the prior art.
Disclosure of Invention
In view of the above, the present invention is directed to a method and a system for controlling the rotational speed of a driving wheel to prevent damage and ablation of a differential.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a driving wheel rotational speed control method comprising: judging whether the current vehicle condition meets a preset wheel speed control condition, and executing the following steps under the condition that the judgment result is yes: the method comprises the steps of obtaining the current rotating speed difference of two driving wheels connected to the same differential mechanism of a vehicle in real time, and controlling the torque value output by the vehicle to be reduced under the condition that the current rotating speed difference is larger than a preset first threshold value; controlling a rotational speed of a drive wheel of the vehicle based on the reduced torque value.
Preferably, the current vehicle condition comprises at least one of: the method comprises the following steps of (1) checking a current vehicle state, a current vehicle fault level, a current vehicle gear, a current vehicle anti-lock brake system state, a current vehicle accelerator opening and a current vehicle wheel speed control function state; wherein the wheel speed control condition includes at least one of: the current vehicle state is a standby state; the current vehicle fault grade is a non-preset fault grade; the current gear of the vehicle is in a driving gear or a reverse gear; the current state of the anti-lock brake system of the vehicle is an un-triggered state; the current accelerator opening degree of the vehicle is larger than the preset accelerator opening degree; the current wheel speed control function of the vehicle verifies that the state is a pass state.
Preferably, the method further comprises determining that the wheel speed control function check state of the current vehicle is a pass state by: acquiring the current rotating speed of a driving wheel of the vehicle and the current speed of the vehicle within a preset time period taking the power-on time point of the vehicle as a starting point, and verifying the wheel speed control function of the current vehicle to be in a passing state under the condition that the current rotating speed of the driving wheel of the vehicle and the current speed of the vehicle are both smaller than a speed threshold value; and/or acquiring the rotating speed of the driving wheel of the vehicle and the rotating speed of the driving motor of the driving wheel of the vehicle in real time, and checking the wheel speed control function of the current vehicle to be in a passing state under the condition that the difference value between the current rotating speed of the driving wheel of the vehicle and the current rotating speed of the motor of the vehicle is smaller than a preset difference value.
Preferably, the controlling the torque value of the vehicle output to be decreased includes: a target torque value is calculated and,controlling the torque value output by the vehicle to decrease to the target torque value; wherein the calculating the target torque value comprises: determining a first current torque coefficient corresponding to the current rotating speed difference in a first compensation ratio table according to a preset first compensation ratio table recorded with the corresponding relation between the rotating speed difference and the first torque coefficient; acquiring the current speed difference change rate in real time, and determining a second current torque coefficient corresponding to the current speed difference change rate in a second compensation ratio table according to a preset second compensation ratio table recorded with the corresponding relation between the speed difference change rate and the second torque coefficient; obtaining a current torque value output by the vehicle in real time, and calculating the target torque value through the following formula:
wherein T is a target torque value; t isSA current torque value output for the vehicle;
is a first current torque coefficient; σ is the second current torque coefficient.
Preferably, after the current rotational speed difference is greater than a preset first threshold, the method further comprises: under the condition that the current rotating speed difference is smaller than a preset second threshold value, controlling the torque value output by the vehicle to change to a required torque value of the vehicle; and/or controlling the vehicle output torque value to change to a preset torque value under the condition that the current rotation speed difference is larger than a preset third threshold value; wherein the second threshold is less than the first threshold, and the first threshold is less than the third threshold.
Preferably, the method of controlling the torque value output by the vehicle to decrease to the target torque value includes: determining a current descending gradient value corresponding to a current torque value output by the vehicle under the torque descending gradient table according to a preset torque descending gradient table recorded with a corresponding relation between the torque value and the descending gradient value, and controlling the torque value output by the vehicle to descend from the current torque value according to the current descending gradient value; the controlling the change in the torque value output by the vehicle to the torque demand value of the vehicle includes: and determining a current ascending gradient value corresponding to the current torque value in the torque ascending gradient table according to a preset torque ascending gradient table recorded with a corresponding relation between the torque value and the ascending gradient value, and controlling the torque value output by the vehicle to ascend from the current torque value according to the current ascending gradient value.
Compared with the prior art, the method for controlling the rotating speed of the driving wheel of the vehicle can control the torque value output by the vehicle to be reduced under the condition that the current rotating speed difference of the two driving wheels is larger than a preset first threshold value for calibrating that the vehicle is in or tends to a unilateral slipping state, thereby protecting a differential, avoiding the damage and ablation of the differential under the condition that the driving wheel of the vehicle slips after being judged to be larger than the preset first threshold value, and improving the driving maneuverability.
The present invention also provides a driving wheel rotational speed control system, including: the vehicle control unit is used for judging whether the current vehicle condition meets a preset wheel speed control condition or not; if the judgment result is yes, the method is used for executing: acquiring the rotation speed difference of two driving wheels connected to the same differential of the vehicle in real time, and controlling the torque value output by the vehicle to be reduced and then output under the condition that the current rotation speed difference is larger than a preset first threshold value; a motor controller for controlling an output power and a rotational speed of a driving motor of the vehicle based on a torque value output from the vehicle, thereby controlling a rotational speed of a driving wheel connected to the driving motor.
Preferably, the vehicle control unit includes: a target torque value calculation module for calculating a target torque value; the torque output module is used for controlling the torque value output by the vehicle to be reduced to the target torque value and then outputting the torque value; wherein the target torque value calculation module includes: the first calculation submodule is used for determining a first current torque coefficient corresponding to the current rotating speed difference in a first compensation ratio table according to the preset first compensation ratio table recorded with the corresponding relation between the rotating speed difference and the first torque coefficient; a second calculation submodule for acquiring the current rotation speed in real timeThe difference change rate is used for determining a second current torque coefficient corresponding to the current speed difference change rate in a second compensation ratio table according to a preset second compensation ratio table recorded with the corresponding relation between the speed difference change rate and the second torque coefficient; and the third calculation submodule is used for acquiring the current torque value output by the vehicle in real time, and calculating the target torque value through the following formula:
wherein T is a target torque value; t isSA current torque value output for the vehicle;
is a first current torque coefficient; σ is the second current torque coefficient.
Preferably, after the current rotation speed difference is greater than a preset first threshold, the vehicle control unit is further configured to control the torque value output by the vehicle to change to a required torque value of the vehicle when the current rotation speed difference is less than a preset second threshold; and/or the vehicle controller is also used for controlling the vehicle output torque value to change to a preset torque value under the condition that the current rotation speed difference is greater than a preset third threshold value; wherein the second threshold is less than the first threshold, and the first threshold is less than the third threshold.
The present disclosure also provides a machine-readable storage medium having stored thereon instructions for causing a machine to execute the above-described driving wheel rotational speed control method.
The driving wheel rotating speed control system and the machine readable storage medium have the same implementation details and advantages as those of the driving wheel rotating speed control method relative to the prior art, and are not described again here.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1a is a flow chart of a driving wheel speed control method according to an embodiment of the present invention;
FIG. 1b is a flow chart of a method for determining wheel speed control conditions;
FIG. 1c is a flow chart of a method for calculating a difference in rotational speed between two drive wheels;
FIG. 2 is a flow chart showing a further modification of the "controlling the decrease in the torque value of the vehicle output" according to the invention;
FIG. 3 is a flowchart illustrating "detailed flowchart for calculating target torque value" in FIG. 2 according to the present invention;
FIG. 4 is a flowchart illustrating the "controlling the torque value output from the vehicle to decrease to the target torque value" in FIG. 2 according to the present invention;
fig. 5 is a flowchart of a further modification of "controlling a change in the torque value output by the vehicle to the required torque value of the vehicle";
FIG. 6 is a block diagram of a drive wheel speed control system.
Description of reference numerals:
10 vehicle control unit 20 motor controller
Detailed Description
In addition, the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict.
The vehicle in the following embodiments is a new energy vehicle, and the control of the execution speed is mainly controlled by a vehicle control unit.
Before describing the present invention in detail, a brief summary of the invention is provided. In the prior art, when a new energy vehicle runs on a low-attachment road surface, if the adhesion force of one side of the ground is smaller than the driving force generated by a motor of the vehicle, the driving wheel on one side of the vehicle slips. If the control is continued in accordance with the torque requested by the driver at this time, it is easy to cause an excessive difference in the rotational speeds of the drive wheels on both sides. When the difference between the rotation speeds of two driving wheels connected to the same differential of the vehicle exceeds 10000 revolutions (the rotation speed of the driving motor of the vehicle exceeds 5000 revolutions), the differential is ablated and damaged. The present invention specifically proposes the following embodiments for avoiding the above-mentioned situation and the problem of ablation and damage of the differential under this condition.
In the following embodiments, the "two drive wheels" are actually left and right drive wheels. In addition, the invention mainly aims at improvement of a rear-drive vehicle.
The present invention is specifically described below by way of examples one to four.
Example one
Fig. 1a is a flowchart of a method for controlling the rotational speed of a driving wheel according to a first embodiment, which mainly describes how to control the rotational speed of the driving wheel to avoid the differential damage caused by continuously increasing the rotational speed of the driving wheel under the condition of unilateral slippage. Fig. 1b is a method for determining wheel speed control conditions according to the first embodiment. Fig. 1c shows a method for calculating a rotational speed difference between two driving wheels according to the first embodiment.
As shown in fig. 1a, the present invention also provides a driving wheel rotation speed control method, which may include:
and S110, judging whether the current vehicle condition meets a preset wheel speed control condition.
Wherein, the preset wheel speed control condition can be adjusted according to the actual situation, and the corresponding current vehicle situation can also be correspondingly changed according to the adjustment of the preset wheel speed control condition. In this embodiment, the current vehicle conditions include, but are not limited to (may be one or more of the following): the method comprises the following steps of checking states of a current vehicle state, a current vehicle fault level, a current vehicle gear, a current vehicle anti-lock brake system state, a current vehicle accelerator opening degree and a current vehicle wheel speed control function. All the states can be acquired by the preset sensors of the vehicle to obtain the specific current state, and the specific acquisition mode does not belong to the protection scope of the invention and is not described herein again. The specific flow of the corresponding preset wheel speed control conditions is shown in fig. 1b, and specifically includes: the current vehicle state is a READY state (the current vehicle state is a READY state); the current vehicle fault level is a non-preset fault level (in the embodiment, it is mainly determined that the vehicle has no high-level fault, and in this case, the vehicle can normally provide driving power); the current gear of the vehicle is in a driving gear or a reverse gear; the current state of the anti-lock brake system of the vehicle is an un-triggered state; the method comprises the steps that the current accelerator opening of a vehicle is larger than a preset accelerator opening, the judgment purpose of the state is mainly to indicate that a driver inputs a driver request torque, wherein the preset accelerator opening is 1%; the current wheel speed control function of the vehicle verifies that the state is a pass state.
Specifically, in this embodiment, the determination to verify that the state is a pass state for the wheel speed control function of the current vehicle mainly includes one of the following two ways or both of the following two ways are satisfied.
The first method is as follows: the method includes the steps that a current rotating speed of a driving wheel of the vehicle and a current vehicle speed of the vehicle are obtained within a preset time period (the preset time period may be 1s after the vehicle is powered on) with a power-on time point of the vehicle as a starting point, and when the current rotating speed of the driving wheel of the vehicle and the current vehicle speed of the vehicle are both smaller than a speed threshold (in the embodiment, the speed threshold may be 5KM/h), a wheel speed control function of the current vehicle verifies a passing state.
When the wheel speed control function verification state is determined only by adopting the first mode, when the acquired state of the vehicle meets all the states (the current rotating speed of the driving wheel and the current vehicle speed of the vehicle cannot exceed 5KM/h), the vehicle is calibrated to be in a passing state, and the vehicle actually shows an opening flag for opening the allowable function, so that the following functions are allowed to be used; when the acquired state of the vehicle does not satisfy all the states described above (one or both of the current rotational speed of the drive wheels and the current vehicle speed of the vehicle exceed 5KM/h), a failed state is designated, and the following functions are prohibited from being used in the current driving cycle actually indicated on the vehicle after the power-on of the vehicle.
The second method comprises the following steps: the method comprises the steps of acquiring the rotating speed of a driving wheel of the vehicle and the rotating speed of a driving motor of the driving wheel of the vehicle in real time, and checking the wheel speed control function of the current vehicle to be in a passing state under the condition that the difference value between the current rotating speed of the driving wheel of the vehicle and the current rotating speed of the motor of the vehicle is smaller than a preset difference value.
The second mode is actually a determination performed after the mode-on flag bit of the mode-on enable function is turned on, and is a continuous determination. In addition, the current rotation speed of the driving wheel of the vehicle is actually the rotation speed of the driving wheel of the vehicle obtained by converting the average wheel speed of the two driving wheels into the rotation speed. In addition, it should be emphasized that the specific values of the current rotational speed of the driving wheel of the vehicle and the current rotational speed of the motor of the vehicle may be acquired by a preset sensor, and then a corresponding difference calculation is performed by a single chip or a processor, which is not described in detail herein. In general, even if one-sided wheel slip occurs, the average rotational speed of the two drive wheels should be the same as the current motor rotational speed. The two conditions are different, and only occur when a fault occurs.
S120, under the condition that the current vehicle condition meets a preset wheel speed control condition, the current rotating speed difference of two driving wheels connected to the same differential mechanism of the vehicle is obtained in real time, and under the condition that the current rotating speed difference is larger than a preset first threshold (the vehicle is calibrated to be in or tend to a single-side slipping state), the torque value output by the vehicle is controlled to be reduced.
In this embodiment, the first threshold is set according to a value corresponding to that the vehicle is in or tends to be in the one-side slip state, the first threshold may be 3500 or another value, which may be changed according to the type and the attribute of the vehicle, and the first threshold may be slightly smaller than the difference between the rotational speeds in the one-side slip state in the experiment, so as to improve safety and avoid accidents. In this step, the torque value output by the vehicle is finally reduced for corresponding subsequent operation. In addition, the above-described current rotational speeds of the two drive wheels connected to the same differential of the vehicle may be obtained by respective wheel speed sensors, and the rotational speed difference may be obtained by the following calculation based on the above-described rotational speeds.
Specifically, as shown in fig. 1c, the calculating, in real time, a rotational speed difference between two driving wheels connected to a same differential of the vehicle includes: the two drive wheels on the same differential of the vehicle include a first drive wheel and a second drive wheel.
S121, acquiring the rotating speed of the first driving wheel, the rotating speed of a motor of the first driving wheel, the diameter of the first driving wheel of the vehicle and the speed ratio of the vehicle in real time, and calculating the current wheel speed of the first driving wheel according to the following formula:
VL＝60×π×DL×nL×ratio/1000；
s122, acquiring the rotating speed of the second driving wheel, the rotating speed of the motor of the second driving wheel and the diameter of the second driving wheel of the vehicle in real time, and calculating the current wheel speed of the second driving wheel according to the following formula:
VR＝60×π×DR×nR×ratio/1000；
s123, calculating a current difference in rotational speed of the first drive wheel and the second drive wheel by the following formula:
VD＝|VL-VR|；
wherein, VLIs the current wheel speed of the first drive wheel, DLIs the diameter, n, of a first driving wheel of said vehicleLThe current motor speed of the first driving wheel; vRFor the current second driving wheel speed, DRIs the diameter, n, of the second driving wheel of the vehicleRThe current motor speed of the second driving wheel; ratio is the speed ratio of the vehicle; vDIs the current difference in rotational speed of the first and second drive wheels.
S130, controlling the rotating speed of the driving wheel of the vehicle based on the reduced torque value.
The reduced torque value is the torque value finally obtained in S120, and the rotation speed of the vehicle drive wheel is controlled based on the torque value. And because the torque value is directly reduced, the rotating speed is reduced, so that the rotating speed difference of the two driving wheels is prevented from being continuously increased, and the differential is protected.
By means of the above-described embodiment, it is possible to achieve protection of the differential, in which, once a single-sided slip of the vehicle occurs, the rotational speeds of the drive wheels are controlled, and the rotational speed difference between the drive wheel on the slip side and the drive wheel on the non-slip side is prevented from being too large by reducing the rotational speeds of the drive wheels, and finally, protection of the differential is achieved.
Example two
Fig. 2 is a flow chart of the second embodiment, wherein the second embodiment is a further improvement made on the basis of the first embodiment. Specifically, a further improvement is made to the "control of the decrease in the torque value output by the vehicle" in the first embodiment. The improved protocol involves essentially two steps, as described below. Fig. 3 is a specific flowchart of "calculating a target torque value". Fig. 4 is a specific flowchart of "controlling the torque value output by the vehicle to decrease to the target torque value".
And S210, calculating a target torque value.
The manner of calculating the target torque value may include S211 to S213 described below, among others. The following is specifically described by S211 to S213.
S211, determining a first current torque coefficient corresponding to the current rotating speed difference in a first compensation ratio table according to the preset first compensation ratio table recorded with the corresponding relation between the rotating speed difference and the first torque coefficient.
Wherein, the first compensation proportion table is as shown in the following table:
from the above table, it can be seen that for each difference in rotational speed, a corresponding first torque factor is associated, for example, in the table, at a difference in rotational speed of 3500, the first torque factor is 100%. The remaining values are not listed in detail here. The first current torque coefficient corresponding to the current rotating speed difference can be obtained through the table, and subsequent calculation is facilitated. Wherein the larger the wheel speed difference, the smaller the first torque coefficient. In addition, "/" in the table indicates a linear change from 3500 to 4000 revolutions, the first torque coefficient being from 100 to 50; further, from 4000 revolutions to 4500 revolutions, the first torque coefficient varies linearly from 50-20, and at greater than 4500 revolutions, the first torque coefficient continues to vary along the 50-20 linear variation curve.
S212, obtaining the current speed difference change rate in real time, and determining a second current torque coefficient corresponding to the current speed difference change rate in a second compensation ratio table according to a preset second compensation ratio table recorded with the corresponding relation between the speed difference change rate and the second torque coefficient.
The change rate of the rotational speed difference can be calculated through the acquired change condition of the rotational speed difference, and the calculation can be executed by adopting a processor or a singlechip. It is noted that, as is clear from the above table, a corresponding second torque coefficient is associated with each differential rotational speed change rate, and for example, when the differential rotational speed change rate is 100 in the table, the second torque coefficient is 0, and the remaining values are not described in detail here. The second current torque coefficient corresponding to the current speed difference change rate can be obtained through the table, and subsequent calculation is facilitated. Wherein the greater the rate of change of the rotational speed difference, the greater the second torque coefficient. Wherein "/" in the table indicates that the rotation speed difference change rate is from 100 to 1000, and the second torque coefficient is linearly changed from 0 to 2; furthermore, from 1000-2000, the second torque coefficient varies linearly from 2-5, and above 2000, the second torque coefficient continues to vary along the 2-5 linear curve.
S213, acquiring the current torque value output by the vehicle in real time, and calculating the target torque value through the following formula:
wherein, in the above formula, T is a target torque value; t isSA current torque value output for the vehicle;
is a first current torque coefficient; σ is the second current torque coefficient.
The torque value output by the vehicle can be obtained through a torque value sensor set by the vehicle, and can also be directly called through a vehicle control unit. The real-time acquisition aims to set a corresponding target torque value according to the actual torque. Through the formula, the target torque value is related to the current torque value, the rotating speed difference and the rotating speed difference change rate, so that the corresponding target torque is set according to the actual condition, and finally, corresponding adjustment is executed according to the actual condition.
And S220, controlling the torque value output by the vehicle to be reduced to the target torque value.
Like the embodiment, the purpose of the reduction is also to achieve the effects of improving safety and avoiding accidents, and the like, and will not be described herein again.
In addition, in S220, further improvement may be made. Specifically, as described in the following S221-S222.
And S221, determining a current descending gradient value corresponding to the current torque value output by the vehicle under the torque descending gradient table according to the preset torque descending gradient table corresponding to the descending gradient value and the torque value.
As can be seen from S213, the current torque value output by the vehicle in this step is obtained in real time. The descending gradient table is a table in which the torque value is the torque value output by the vehicle, and the gradient value is the descending gradient value.
As can be seen from the above table, the larger the torque value of the vehicle output, the larger the gradient of the decline. Thereby achieving a faster vehicle deceleration. By the aid of the mode, smooth adjustment is guaranteed, and sudden change is avoided. Wherein "/" in the table indicates a linear variation of torque values from 0-150 and decreasing gradient values from 100-150; furthermore, from between 150-.
And S222, controlling the torque value output by the vehicle to descend from the current torque value according to the current descending gradient value.
And the current descending gradient value is obtained according to the descending gradient table, corresponding descending of the torque value output by the vehicle is executed, and finally the speed of the vehicle is reduced.
Through the implementation mode, the vehicle can be enabled to execute the speed reduction according to the direction of the target torque value reflecting the current vehicle condition, the current actual condition is fully considered, and the current requirement at the current stage can be better met. In addition, the specially designed reduction mode can ensure smooth adjustment and avoid sudden change.
EXAMPLE III
Embodiment three is a further improvement made on the basis of embodiment two, wherein the control unit is mainly configured to control a situation after the torque value output by the vehicle is reduced in a case where the current rotation speed difference is larger than a preset first threshold value (which is used for marking that the vehicle is in or tends to a one-side slip state). Two possible cases are mainly included in the third embodiment, as described below. Fig. 5 is a detailed flowchart of a further modification of the third embodiment, that is, the first aspect is a case where "the torque value output by the vehicle is controlled to be changed to the required torque value of the vehicle";
the first condition is as follows: and under the condition that the current rotating speed difference is smaller than a preset second threshold value (demarcating that the vehicle is released to be in or tends to a one-side slip state), controlling the torque value output by the vehicle to change to the required torque value of the vehicle.
In the first situation, the current speed difference is collected in real time and can change according to the actual situation. When the rotation speed difference of the driving wheels of the vehicle is found to be smaller than the second threshold value after the torque value output by the vehicle is controlled to be reduced in the manner of the invention, the calibrated smaller than the second threshold value is also determined according to the actual situation, and the specific design can be 3000. The required torque value of the vehicle may be a driver requested torque value.
In addition, in this embodiment, a further improvement is made with respect to the manner in which the "torque value that controls the vehicle output is changed to the required torque value of the vehicle", specifically, as described below.
As shown in fig. 5, S311, determining a current rising gradient value corresponding to a current torque value output by the vehicle in the torque rising gradient table according to the preset torque value and the torque rising gradient table corresponding to the rising gradient value;
the current torque value output by the vehicle is obtained in real time, and the current ascending gradient value can be obtained through the following table. The table is shown below.
From the above table, it can be known that the larger the torque value is, the larger the rising gradient value is, which ensures smooth adjustment and avoids sudden change. Wherein "/" in the table indicates a linear variation of torque values from 0 to 150 and rising gradient values from 30 to 50; furthermore, from 150-300, the rising gradient value varies linearly from 50-90.
And S322, controlling the torque value output by the vehicle to rise from the current torque value according to the current rising gradient value.
Wherein the current rising gradient value is obtained according to the rising gradient table, and corresponding rising of the torque value output by the vehicle is executed, and finally the speed reduction of the vehicle is realized.
Case two: and controlling the output torque value of the vehicle to change to a preset torque value when the current rotation speed difference is larger than a preset third threshold value (calibrating the maximum value of the correctable torque of the vehicle).
In the second case, it is found that the reduction of the rotational speed difference between the two wheels is still unavoidable by controlling the reduction of the torque value output by the vehicle, and the vehicle output torque value is directly changed to a preset torque value, where the preset torque value is less than or equal to 2n.m, and is used for limiting the maximum correctable torque value of the entire torque correction function.
Through the mode, the phenomenon that the rotating speed difference is too large after the driving wheel slips can be effectively avoided, the differential is prevented from being damaged, the control can be timely quitted, the controllability of driving is improved, and the actual requirement on the vehicle is met.
Example four
FIG. 6 is a block diagram of a drive wheel speed control system.
As shown in fig. 6, a driving wheel rotational speed control system includes: the vehicle control unit 10 is configured to determine whether a current vehicle condition meets a preset wheel speed control condition, and start the function calculation module when the current vehicle condition meets the preset wheel speed control condition; the device is also used for acquiring the rotating speed difference of two driving wheels connected to the same differential mechanism of the vehicle in real time, and controlling the torque value output by the vehicle to be output after being reduced under the condition that the current rotating speed difference is larger than a preset first threshold (for calibrating that the vehicle is in or tends to a single-side slipping state); a motor controller 20 for controlling an output power and a rotation speed of a driving motor of the vehicle based on a torque value output from the vehicle, thereby controlling the rotation speed of a driving wheel connected to the driving motor.
Preferably, the controlling the vehicle control unit 10 for controlling the output of the vehicle with the reduced torque value includes: a target torque value calculation module for calculating a target torque value; and the torque output module is used for controlling the torque value output by the vehicle to be reduced to the target torque value and then outputting the torque value. Wherein the target torque value calculation module includes: and the first calculation submodule is used for determining a first current torque coefficient corresponding to the rotating speed difference in a first compensation ratio table according to the preset first compensation ratio table recorded with the corresponding relation between the rotating speed difference and the first torque coefficient. And the second calculation submodule is used for acquiring the current speed difference change rate in real time, and determining a second current torque coefficient corresponding to the current speed difference change rate in a second compensation ratio table according to the preset second compensation ratio table in which the corresponding relation between the speed difference change rate and a second torque coefficient is recorded. The third calculation submodule is used for acquiring the current torque value output by the vehicle in real time, and calculating the target torque value through the following formula:
wherein T is a target torque value; t is a unit ofSA current torque value output for the vehicle;
is a first current torque coefficient; σ is the second current torque coefficient.
Preferably, the torque output module is configured to determine, according to a preset torque reduction gradient table in which a torque value corresponds to a reduction gradient value, a current reduction gradient value corresponding to a current torque value output by the vehicle in the torque reduction gradient table, and control the torque value output by the vehicle to be reduced from the current torque value according to the current reduction gradient value.
Preferably, after the current rotation speed difference is greater than a preset first threshold, the vehicle control unit is further configured to control the torque value output by the vehicle to change to a required torque value of the vehicle (actually, the torque output module of the vehicle control unit controls) when the current rotation speed difference is less than a preset second threshold. After the current rotation speed difference is greater than a preset first threshold, the vehicle controller is configured to control the torque value output by the vehicle to change to a preset torque value (actually, the torque output module of the vehicle controller controls) under the condition that the current rotation speed difference is greater than a preset third threshold. Wherein the second threshold is less than the first threshold, and the first threshold is less than the third threshold.
Preferably, the torque output module of the vehicle control unit determines a current descending gradient value corresponding to a current torque value output by the vehicle in a preset torque descending gradient table recorded with a corresponding relationship between the torque value and the descending gradient value, and controls the torque value output by the vehicle to descend from the current torque value according to the current descending gradient value; and/or said controlling the change in the torque value output by the vehicle to the requested torque value of the vehicle comprises: and determining a current ascending gradient value corresponding to the current torque value in the torque ascending gradient table according to a preset torque ascending gradient table recorded with a corresponding relation between the torque value and the ascending gradient value, and controlling the torque value output by the vehicle to ascend from the current torque value according to the current ascending gradient value.
Compared with the prior art, the implementation details and the advantages of the driving wheel rotating speed control system and the driving wheel rotating speed control method are the same, and are not described again.
The present application further provides a computer program product adapted to perform a program of initializing the method steps of the first, second and third embodiment when executed on a data processing device.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
In a typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.
The memory may include forms of volatile memory in a computer readable medium, Random Access Memory (RAM) and/or non-volatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). The memory is an example of a computer-readable medium.
Computer-readable media, including both permanent and non-permanent, removable and non-removable media, may implement the information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, a computer readable medium does not include a transitory computer readable medium such as a modulated data signal and a carrier wave.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or apparatus that comprises the element.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be taken as limiting the scope of the present invention, which is intended to cover any modifications, equivalents, improvements, etc. within the spirit and scope of the present invention.
Claims (8)
1. A driving wheel rotational speed control method characterized by comprising:
judging whether the current vehicle condition meets a preset wheel speed control condition,
if the judgment result is yes, executing:
the method comprises the steps of acquiring the current rotation speed difference of two driving wheels connected to the same differential mechanism of a vehicle in real time, and controlling the torque value output by the vehicle to be reduced under the condition that the current rotation speed difference is larger than a preset first threshold value, wherein the control comprises the following steps:
calculating a target torque value, and controlling the torque value output by the vehicle to be reduced to the target torque value;
wherein the calculating the target torque value comprises:
determining a first current torque coefficient corresponding to the current rotating speed difference in a first compensation ratio table according to the preset first compensation ratio table recorded with the corresponding relation between the rotating speed difference and the first torque coefficient;
acquiring the current speed difference change rate in real time, and determining a second current torque coefficient corresponding to the current speed difference change rate in a second compensation ratio table according to a preset second compensation ratio table recorded with the corresponding relation between the speed difference change rate and the second torque coefficient;
obtaining a current torque value output by the vehicle in real time, and calculating the target torque value through the following formula:
wherein T is a target torque value; t isSA current torque value output for the vehicle;
is a first current torque coefficient; σ is a second current torque coefficient;
controlling a rotational speed of a drive wheel of the vehicle based on the reduced torque value.
2. The driving wheel rotational speed control method according to claim 1,
the current vehicle condition includes at least one of: the method comprises the following steps of (1) checking a current vehicle state, a current vehicle fault level, a current vehicle gear, a current vehicle anti-lock brake system state, a current vehicle accelerator opening and a current vehicle wheel speed control function state;
wherein the wheel speed control condition includes at least one of:
the current vehicle state is a standby state;
the current vehicle fault grade is a non-preset fault grade;
the current gear of the vehicle is in a driving gear or a reverse gear;
the current state of the anti-lock brake system of the vehicle is an un-triggered state;
the current accelerator opening degree of the vehicle is larger than the preset accelerator opening degree; and
the current wheel speed control function of the vehicle verifies that the state is a pass state.
3. The driving wheel speed control method according to claim 2, further comprising determining the current wheel speed control function verification state of the vehicle as a pass state by:
acquiring the current rotating speed of a driving wheel of the vehicle and the current speed of the vehicle within a preset time period taking the power-on time point of the vehicle as a starting point, and verifying the wheel speed control function of the current vehicle to be in a passing state under the condition that the current rotating speed of the driving wheel of the vehicle and the current speed of the vehicle are both smaller than a speed threshold value; and/or
The method comprises the steps of acquiring the rotating speed of a driving wheel of the vehicle and the rotating speed of a driving motor of the driving wheel of the vehicle in real time, and checking the current wheel speed control function of the vehicle to be in a passing state under the condition that the difference value between the current rotating speed of the driving wheel of the vehicle and the current rotating speed of the motor of the vehicle is smaller than a preset difference value.
4. The drive wheel rotation speed control method according to any one of claims 1 to 3,
after the current rotational speed difference is greater than a preset first threshold, the method further comprises:
under the condition that the current rotating speed difference is smaller than a preset second threshold value, controlling the torque value output by the vehicle to change to a required torque value of the vehicle; and/or
Under the condition that the current rotating speed difference is larger than a preset third threshold value, controlling the output torque value of the vehicle to change to a preset torque value;
wherein the second threshold is less than the first threshold, and the first threshold is less than the third threshold.
5. The driving wheel speed control method according to claim 4, characterized in that the method of controlling the decrease of the torque value output by the vehicle to the target torque value includes:
determining a current descending gradient value corresponding to a current torque value output by the vehicle under the torque descending gradient table according to a preset torque descending gradient table recorded with a corresponding relation between the torque value and the descending gradient value, and controlling the torque value output by the vehicle to descend from the current torque value according to the current descending gradient value; and/or
The controlling the change in the torque value output by the vehicle to the torque demand value of the vehicle includes:
and determining a current ascending gradient value corresponding to the current torque value in the torque ascending gradient table according to a preset torque ascending gradient table recorded with a corresponding relation between the torque value and the ascending gradient value, and controlling the torque value output by the vehicle to ascend from the current torque value according to the current ascending gradient value.
6. A drive wheel rotational speed control system, characterized by comprising:
the vehicle control unit is used for judging whether the current vehicle condition meets a preset wheel speed control condition or not;
if the judgment result is yes, the method is used for executing:
acquiring the rotation speed difference of two driving wheels connected to the same differential mechanism of the vehicle in real time, and controlling the torque value output by the vehicle to be reduced and then output under the condition that the current rotation speed difference is larger than a preset first threshold value;
wherein, the vehicle control unit is used for controlling the output of the vehicle after the torque value output by the vehicle is reduced, and the output comprises:
a target torque value calculation module for calculating a target torque value;
the torque output module is used for controlling the torque value output by the vehicle to be reduced to the target torque value and then outputting the torque value;
wherein the target torque value calculation module includes:
the first calculation submodule is used for determining a first current torque coefficient corresponding to the current rotating speed difference in a first compensation ratio table according to the preset first compensation ratio table recorded with the corresponding relation between the rotating speed difference and a first torque coefficient;
the second calculation submodule is used for acquiring the current speed difference change rate in real time, and determining a second current torque coefficient corresponding to the current speed difference change rate in a second compensation ratio table according to the preset second compensation ratio table in which the corresponding relation between the speed difference change rate and a second torque coefficient is recorded; and
the third calculation submodule is used for acquiring the current torque value output by the vehicle in real time, and calculating the target torque value through the following formula:
wherein T is a target torque value; t isSA current torque value output for the vehicle;
is a first current torque coefficient; σ is a second current torque coefficient;
a motor controller for controlling an output power and a rotational speed of a driving motor of the vehicle based on a torque value output from the vehicle, thereby controlling a rotational speed of a driving wheel connected to the driving motor.
7. The drive wheel rotational speed control system according to claim 6,
after the current difference in rotational speed is greater than a preset first threshold,
the vehicle control unit is further used for controlling the torque value output by the vehicle to change to the required torque value of the vehicle under the condition that the current rotation speed difference is smaller than a preset second threshold value; and/or
The vehicle control unit is also used for controlling the vehicle output torque value to change to a preset torque value under the condition that the current rotation speed difference is larger than a preset third threshold value;
wherein the second threshold is less than the first threshold, and the first threshold is less than the third threshold.
8. A machine-readable storage medium having stored thereon instructions for causing a machine to perform the drive wheel speed control method of any one of claims 1-5.
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| CN114954027A (en) * | 2021-07-20 | 2022-08-30 | 长城汽车股份有限公司 | Control method and device for motor of electric automobile and vehicle |
| CN113726227A (en) * | 2021-09-08 | 2021-11-30 | 潍柴动力股份有限公司 | Motor control method, device, equipment, storage medium and product |
| CN115107914B (en) * | 2022-06-07 | 2023-10-20 | 天津爱玛车业科技有限公司 | Anti-skid vehicle body stabilization system and method for electric vehicle |
| CN115324148B (en) * | 2022-08-17 | 2023-06-16 | 三一重机有限公司 | Fault protection control method and device for electric engineering machinery and electric engineering machinery |
| WO2024197769A1 (en) * | 2023-03-31 | 2024-10-03 | 华为技术有限公司 | Vehicle control method, apparatus, vehicle and storage medium |
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