阅读说明：本技术 四轮无转向机构分布式驱动汽车防滑控制方法、装置 (Four-wheel non-steering mechanism distributed drive automobile anti-skid control method and device ) 是由 何世涛 曲秀兰 刘鸿鹏 于 2021-01-07 设计创作，主要内容包括：本发明提供一种四轮无转向机构分布式驱动汽车防滑控制方法、装置,首先,根据方向盘转角进行行驶工况判断,行驶工况分为直线行驶和转向行驶；之后,实时计算每个车轮的当前滑移率Si,并与当前行驶工况下的门限值滑移率S0进行对比,判断是否打滑,当Si≥S0时判断为发生打滑,若发生打滑,则启动驱动防滑控制；通过当前滑移率与设定的滑移率S0的差值的变化率实时进行PID调节得到修正扭矩；最后,将发生打滑的车轮扭矩修正后的扭矩减少量分配到其他车轮上进行扭矩补偿,使得驾驶员驾驶意图得到最大限度的实现。本发明将打滑车轮扭矩修正后的扭矩减少量分配到其他车轮上进行扭矩补偿,极大提高了驱动防滑效果、车辆操作稳定性和安全性。(The invention provides a four-wheel non-steering mechanism distributed drive automobile anti-skid control method and a device, firstly, judging the driving condition according to the steering wheel angle, wherein the driving condition comprises straight driving and steering driving; then, calculating the current slip rate Si of each wheel in real time, comparing the current slip rate Si with a threshold slip rate S0 under the current driving working condition, judging whether the wheels slip or not, judging that the wheels slip when the Si is larger than or equal to S0, and starting driving anti-slip control if the wheels slip; carrying out PID adjustment in real time according to the change rate of the difference value between the current slip rate and the set slip rate S0 to obtain a correction torque; and finally, distributing the torque reduction amount after the wheel torque correction of the slipping to other wheels for torque compensation, so that the driving intention of the driver is realized to the maximum extent. The invention distributes the torque reduction amount after the torque correction of the slipping wheel to other wheels for torque compensation, thereby greatly improving the driving antiskid effect, the vehicle operation stability and the safety.)

1. The four-wheel steering mechanism-free distributed drive automobile antiskid control method is characterized by comprising the following steps of:

step 1, judging a driving condition: monitoring the steering wheel angle, judging the driving condition according to the steering wheel angle, judging the driving condition to be straight-line driving when the steering wheel angle is zero, and judging the driving condition to be steering when the steering wheel angle is non-zero;

step 2, judging slippage: calculating the current slip rate Si of each wheel in real time, comparing the current slip rate Si with a threshold slip rate S0 under the current driving working condition, judging whether the wheels slip, judging that the wheels slip when the Si is larger than or equal to S0, and starting driving anti-slip control if the wheels slip; performing proportional-integral-derivative linear regulation in real time according to the change rate of the difference between the current slip rate and the set slip rate S0 to obtain a correction torque, wherein the correction torque and the calculated torque generate a difference;

step 3, torque redistribution: and distributing the torque reduction amount after the wheel torque correction of the slipping to other wheels for torque compensation, so that the driving intention of the driver is realized to the maximum extent.

2. The distributed drive automobile anti-skid control method for four-wheel non-steering mechanism according to claim 1, wherein in step 3, if slipping occurs and the driving condition is determined as straight driving, the torque difference generated by the slipping wheel correction torque and the calculated torque is preferentially compensated by the non-slipping wheels on the same side, and when the wheels on the same side cannot be completely compensated, the compensation is performed by the wheels on the other side, so as to ensure that the sum TL 'of the left wheel torques after torque correction is equal to the sum TR' of the right wheel torques after torque correction and the torque direction is unchanged.

3. The four-wheel non-steering mechanism distributed drive automobile anti-skid control method according to claim 2, characterized in that in step 3, if the skid occurs and the driving condition is judged to be straight driving, the straight driving comprises forward gear straight driving and reverse gear straight driving, and the torque compensation principle is the same when the forward gear straight driving and the reverse gear straight driving are performed;

when the straight line driving is the forward gear straight line driving, the concrete torque compensation principle is as follows:

defining: calculating a torque Ti, wherein the corrected torque Ti ' is a slip wheel correction torque deviation Δ Ti ' according to a torque correction principle Ti ' >0, and the non-slip wheel surplus torque is Δ Ti, wherein i is 1, 2, 3, 4, and i is 1 denotes a front left wheel, i is 2 denotes a front right wheel, i is 3 denotes a rear left wheel, and i is 4 denotes a rear right wheel;

the principle of torque compensation is the same when the single wheel skids, and when the left front wheel skids, the principle of torque compensation is as follows:

when Δ T2> Δ T1'; the left rear wheel correction torque is T2+ Δ T1'; the torque of each wheel is as follows:

T1′；T2+ΔT1′；T3；T4；

when Δ T2<Δ T1'; the torque of the non-slipping wheel on the same side cannot be completely compensated, and the compensation value is delta T2; the torque compensation value required by the opposite side is delta T2-delta T1'; getThe torque of each wheel is as follows:

T1′；T2+ΔT2；

the torque compensation principle is the same when the two wheels on the same side slip, and when the two wheels on the left side slip, the torque compensation principle is taken The torque of each wheel is as follows:

T1′；T2′；

the principle of torque compensation is the same when the two wheels on different sides slip, and when the left front wheel and the right front wheel slip, the torque compensation is taken

If it is notThe wheel torque distribution is then:

T1′；T3′；

if it is notThe wheel torque distribution is then:

T1′；T2+ΔT2；T3′；

if it is notThe wheel torque distribution is then:

T1′；T3′；T4+ΔT2；

the principle of torque compensation is the same when three wheels slip, and when three wheels slip, namely 2, 3 and 4, the torque compensation is taken

If it is notThe wheel torque distribution is then:

T1+ΔT1；T2′，T3′，T4′；

if it is notThe wheel torque distribution is then:

T2′，T3′，T4′；

when the four wheels slip, take

If it is notThe wheel torque distribution is then:

T3′；T4′；

if it is notThe wheel torque distribution is then:

T1′；T2′；

4. the four-wheel non-steering mechanism distributed drive automobile anti-skid control method according to claim 2, characterized in that in step 3, if no skid occurs and the driving condition is judged to be straight driving, the torque is proportionally distributed to the motors on two sides according to the driver driving torque demand TD, and the distribution formula is as follows:

wherein TD is the calculated total torque; TR is the sum of the right wheel torques; TL is the sum of left wheel torques.

5. The four-wheel non-steering mechanism distributed drive automobile anti-skid control method according to claim 2, characterized in that in step 3, if no skid occurs and the driving condition is judged to be steering, and when TR is less than or equal to Tmax, in order to meet the yaw torque without affecting the acceleration demand of the driver, the torque distribution formula is as follows:

wherein TD is the calculated total torque; TR is the sum of the right wheel torques; TL is the sum of left wheel torques; mz is yaw torque demand; tmax is the motor output torque limit.

6. The four-wheel non-steering mechanism distributed drive automobile anti-skid control method according to claim 2, characterized in that in step 3, if the slip occurs and the driving condition is judged to be steering, and at the same time, TR is greater than Tmax, the torque distribution formula is as follows:

TL＝Tmax-2Mz；

TR＝Tmax；

wherein TR is the sum of the right wheel torques; TL is the sum of left wheel torques; mz is yaw torque demand; tmax is a motor output torque limit value; the torque of the right wheel is ensured to be greater than 0 when the forward gear rotates left, and the torque of the left wheel is ensured to be greater than 0 when the forward gear rotates right; ensuring that the torque of the right wheel is less than 0 when the vehicle is in reverse gear and left-turning; ensuring that the torque of a left wheel is less than 0 when the vehicle is in reverse gear and turns right; the torque distribution is the same as for straight travel.

7. The utility model provides a four-wheel does not have steering mechanism distributed drive car antiskid controlling means which characterized in that includes:

the driving condition judging module is used for judging whether the driving condition is straight driving or steering according to the steering angle of the steering wheel and the gear information of the gearbox monitored in real time;

the slip judging module is used for calculating the current slip rate Si of each wheel in real time, comparing the current slip rate Si with the threshold slip rate S0 under the current driving working condition, judging whether the wheels slip or not, judging that slip occurs when the Si is larger than or equal to S0, and starting driving anti-slip control if the wheels slip; PID adjustment is carried out in real time according to the change rate of the difference between the current slip rate and the set slip rate S0 to obtain a correction torque, and the correction torque and the calculated torque generate a difference at the moment;

a torque redistribution module: and distributing the torque reduction amount after the wheel torque correction of the slipping to other wheels for torque compensation, so that the driving intention of the driver is realized to the maximum extent.

Technical Field

The invention relates to the technical field of vehicle anti-skid control methods, in particular to a four-wheel steering mechanism-free distributed drive vehicle anti-skid control method and device.

Background

The four-wheel hub motor differential steering automobile has the greatest advantage that the motor is adopted for driving, so that the torques of four wheels can be independently and accurately controlled, and the controllable degree of freedom and the safety of the automobile can be greatly improved. The control of the safety of the vehicle is divided into active safety control and passive safety control such as a safety belt, an air bag, etc., and the electric vehicle driving antiskid control system is an electric vehicle active safety control system in which the output torque of a motor may exceed the torque corresponding to the maximum adhesion force that can be provided by the ground when the vehicle is driven on a low adhesion road surface, particularly, when the vehicle is accelerated. When the condition happens, the difference between the wheel speed and the vehicle speed is larger and larger, so that the wheel rapidly slides, the wheel sliding rate enters an unstable area through a stable area, the ground adhesion is further reduced, and safety accidents are possibly caused.

At present, a drive anti-skid system of a motor drive vehicle pair generally adopts a traditional logic threshold value control method, PID control, fuzzy control and other methods, wherein PID is an English acronym of proportional-integral-differential. The PID control method is widely applied, the slip rate of the wheels is monitored in real time, the torque is corrected in time when the wheels slip, however, the difference between the corrected torque and the calculated expected torque can cause the left side and the right side to generate unexpected yaw torque, the problem of inconsistency with the driving intention of a driver exists, and hidden dangers are brought to the operation stability and the safety of the vehicle.

Therefore, a new method for controlling the slip of the vehicle needs to be researched.

Disclosure of Invention

In view of the above, the invention provides a four-wheel steering mechanism-free distributed drive automobile anti-skid control method and device, which allocate the torque reduction amount after correcting the torque of a slipping wheel to other wheels for torque compensation on the basis of PID (proportion integration differentiation) adjustment, so that the driving intention of a driver is realized to the maximum extent, and the drive anti-skid effect, the vehicle operation stability and the safety are greatly improved.

In order to solve the technical problems, the invention adopts the following technical scheme:

the anti-skid control method for the four-wheel steering-mechanism-free distributed drive automobile comprises the following steps:

step 1, judging a driving condition: monitoring the steering wheel angle, judging the driving condition according to the steering wheel angle, judging the driving condition to be straight-line driving when the steering wheel angle is zero, and judging the driving condition to be steering when the steering wheel angle is non-zero;

step 2, judging slippage: calculating the current slip rate Si of each wheel in real time, comparing the current slip rate Si with a threshold slip rate S0 under the current driving working condition, judging whether the wheels slip, judging that the wheels slip when the Si is larger than or equal to S0, and starting driving anti-slip control if the wheels slip; performing proportional-integral-derivative linear regulation in real time according to the change rate of the difference value between the current slip rate and the set slip rate S0, namely PID regulation to obtain a correction torque, wherein the correction torque and the calculated torque generate a difference value;

step 3, torque redistribution: and distributing the torque reduction amount after the wheel torque correction of the slipping to other wheels for torque compensation, so that the driving intention of the driver is realized to the maximum extent.

Further, in step 3, if slipping occurs and the driving condition is determined to be straight driving, the torque difference generated by the slipping correction torque and the calculated torque is preferentially compensated by the non-slipping wheels on the same side, and when the wheels on the same side cannot be completely compensated, the wheel on the other side is compensated to ensure that the sum TL 'of the left wheel torques after torque correction is equal to the sum TR' of the right wheel torques after torque correction and the torque direction is unchanged.

Further, in step 3, if the slip occurs and the driving condition is judged to be straight driving, the straight driving comprises forward gear straight driving and reverse gear straight driving, and the torque compensation principle is the same when the forward gear straight driving and the reverse gear straight driving are performed;

when the straight line driving is the forward gear straight line driving, the concrete torque compensation principle is as follows:

defining: calculating a torque Ti, wherein the corrected torque Ti ' is a slip wheel correction torque deviation Δ Ti ' according to a torque correction principle Ti ' >0, and the non-slip wheel surplus torque is Δ Ti, wherein i is 1, 2, 3, 4, and i is 1 denotes a front left wheel, i is 2 denotes a front right wheel, i is 3 denotes a rear left wheel, and i is 4 denotes a rear right wheel;

(1) the principle of torque compensation is the same when the single wheel skids, and when the left front wheel skids, the principle of torque compensation is as follows:

when Δ T2> Δ T1'; the left rear wheel correction torque is T2+ Δ T1'; the torque of each wheel is as follows:

T1′；T2+ΔT1′；T3；T4；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

when Δ T2<Δ T1'; the torque of the non-slipping wheel on the same side cannot be completely compensated, and the compensation value is delta T2; the torque compensation value required by the opposite side is delta T2-delta T1'; getThe torque of each wheel is as follows:

T1′；T2+ΔT2；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

(2) the torque compensation principle is the same when the two wheels on the same side slip, and when the two wheels on the left side slip, the torque compensation principle is takenThe torque of each wheel is as follows:

T1′；T2′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

(3) the principle of torque compensation is the same when the two wheels on different sides slip, and when the left front wheel and the right front wheel slip, the torque compensation is taken

If it is notThe wheel torque distribution is then:

T1′；T3′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

if it is notThe wheel torque distribution is then:

T1′；T2+ΔT2；T3′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

if it is notThe wheel torque distribution is then:

T1′；T3′；T4+ΔT2；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively; (4) the principle of torque compensation is the same when three wheels slip, when i equals to 2, 3 and 4 wheels slip,

get

If it is notThe wheel torque distribution is then:

T1+ΔT1；T2′，T3′，T4′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

if it is notThe wheel torque distribution is then:

T2′，T3′，T4′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

(5) when the four wheels slip, take

If it is notThe wheel torque distribution is then:

T3′；T4′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

if it is notThe wheel torque distribution is then:

T1′；T2′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively.

Further, in step 3, if no slip occurs and the driving condition is determined to be straight driving, the torque is proportionally distributed to the motors on the two sides according to the driver driving torque demand TD, and the distribution formula is as follows:

wherein TD is the calculated total torque; TR is the sum of the right wheel torques; TL is the sum of left wheel torques.

Further, in step 3, if no slip occurs and the driving condition is determined as steering, and TR is less than or equal to Tmax, in order to satisfy the yaw torque without affecting the acceleration demand of the driver, the torque distribution formula is:

wherein TD is the calculated total torque; TR is the sum of the right wheel torques; TL is the sum of left wheel torques; mz is yaw torque demand; tmax is the motor output torque limit.

Further, in step 3, if the slip occurs and the driving condition is determined as steering, and TR > Tmax, the torque distribution formula is as follows:

TL＝Tmax-2Mz；

TR＝Tmax；

wherein TR is the sum of the right wheel torques; TL is the sum of left wheel torques; mz is yaw torque demand; tmax is a motor output torque limit value; the torque of the right wheel is ensured to be greater than 0 when the forward gear rotates left, and the torque of the left wheel is ensured to be greater than 0 when the forward gear rotates right; ensuring that the torque of the right wheel is less than 0 when the vehicle is in reverse gear and left-turning; ensuring that the torque of a left wheel is less than 0 when the vehicle is in reverse gear and turns right; the torque distribution is the same as for straight travel.

The invention also provides a four-wheel steering mechanism-free distributed drive automobile antiskid control device, which comprises:

the driving condition judging module is used for judging whether the driving condition is straight driving or steering according to the steering angle of the steering wheel and the gear information of the gearbox monitored in real time;

the slip judging module is used for calculating the current slip rate Si of each wheel in real time, comparing the current slip rate Si with the threshold slip rate S0 under the current driving working condition, judging whether the wheels slip or not, judging that slip occurs when the Si is larger than or equal to S0, and starting driving anti-slip control if the wheels slip; PID adjustment is carried out in real time according to the change rate of the difference between the current slip rate and the set slip rate S0 to obtain a correction torque, and the correction torque and the calculated torque generate a difference at the moment;

a torque redistribution module: and distributing the torque reduction amount after the wheel torque correction of the slipping to other wheels for torque compensation, so that the driving intention of the driver is realized to the maximum extent.

The technical scheme of the invention has the following beneficial effects:

the invention aims at the problem that in the prior art, a drive antiskid system of a motor drive vehicle pair generally adopts a traditional logic threshold value control method, a PID control method, a fuzzy control method and the like. The PID control method is widely applied, the slip rate of the wheels is monitored in real time, the torque is corrected in time when the wheels slip, however, the difference between the corrected torque and the calculated expected torque can cause the left side and the right side to generate unexpected yaw torque, the problem of inconsistency with the driving intention of a driver exists, and the technical problem of hidden danger is brought to the operation stability and the safety of the vehicle. The anti-skid control method for the four-wheel steering-mechanism-free distributed drive automobile is characterized by comprising the following steps of firstly, judging the driving working condition: monitoring the steering wheel angle, judging the driving condition according to the steering wheel angle, judging the driving condition to be straight-line driving when the steering wheel angle is zero, and judging the driving condition to be steering when the steering wheel angle is non-zero; after that, the skid is judged: calculating the current slip rate Si of each wheel in real time, comparing the current slip rate Si with a threshold slip rate S0 under the current driving working condition, judging whether the wheels slip, judging that the wheels slip when the Si is larger than or equal to S0, and starting driving anti-slip control if the wheels slip; PID adjustment is carried out in real time according to the change rate of the difference between the current slip rate and the set slip rate S0 to obtain a correction torque, and the correction torque and the calculated torque generate a difference at the moment; finally, torque redistribution: and distributing the torque reduction amount after the wheel torque correction of the slipping to other wheels for torque compensation, so that the driving intention of the driver is realized to the maximum extent.

According to the invention, on the basis of PID adjustment, the torque reduction amount after the torque correction of the slipping wheel is distributed to other wheels for torque compensation, so that the driving intention of a driver is realized to the maximum extent, and the driving anti-slipping effect, the vehicle operation stability and the safety are greatly improved.

Drawings

FIG. 1 is a block diagram of a four-wheel non-steering mechanism distributed drive automobile anti-skid control method of the present invention;

FIG. 2 is a control flow chart of the anti-skid control method of the four-wheel non-steering mechanism distributed drive automobile of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings of the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.

The following describes a four-wheel non-steering mechanism distributed drive automobile anti-skid control method according to an embodiment of the present invention with reference to fig. 1 and fig. 2, including the following steps:

step 1, judging a driving condition: monitoring the steering wheel angle, judging the driving condition according to the steering wheel angle, judging the driving condition to be straight-line driving when the steering wheel angle is zero, and judging the driving condition to be steering when the steering wheel angle is non-zero;

step 2, judging slippage: calculating the current slip rate Si of each wheel in real time, comparing the current slip rate Si with a threshold slip rate S0 under the current driving working condition, judging whether the wheels slip, judging that the wheels slip when the Si is larger than or equal to S0, and starting driving anti-slip control if the wheels slip; PID adjustment is carried out in real time according to the change rate of the difference between the current slip rate and the set slip rate S0 to obtain a correction torque, and the correction torque and the calculated torque generate a difference at the moment;

step 3, torque redistribution: and distributing the torque reduction amount after the wheel torque correction of the slipping to other wheels for torque compensation, so that the driving intention of the driver is realized to the maximum extent.

The threshold slip ratio S0 is set according to vehicle design and different driving conditions, and S0 generally takes a value of 0.15-0.25.

The torque distribution module respectively calculates the motor torques at two sides of the vehicle and simultaneously meets the requirements of the driving force of a driver and the special yaw torque. The driver driving torque requirement is calculated by a formula, and under the normal straight line driving working condition, the torque is distributed to the motors on the two sides in equal proportion, namely:TD is the calculated total torque; TR is the sum of the right wheel torques; TL is the sum of left wheel torques;

the differential steering vehicle is different from the traditional vehicle based on the ackerman steering, the differential steering vehicle has no mechanical steering mechanism, the definite geometric relationship between the steering wheel and the steering radius of the vehicle can not be determined, the steering function of the vehicle must depend on the wheel speed difference of the left and the right wheels to generate the yaw rate to complete the steering, and therefore the relationship between the steering wheel angle and the reference yaw rate can be determined according to requirements. In order to meet the yaw torque without affecting the acceleration demand of the driver during steering, the following allocation method is designed: when the required longitudinal force is large, however, the driver's required longitudinal force conflicts with the required yaw torque due to the limitations of the motor-external characteristics, since differential steering has no mechanical steering mechanism for the vehicle,from a safety point of view, it is necessary to ensure that the vehicle has sufficient steering capacity under any operating conditions, so that when the electric machine is unable to meet both the driver acceleration and yaw torque requirements, such as TR>Tmax, the yaw torque demand should be met preferentially, and then the distribution is carried out according to the following formula:

TL-Tmax-2 Mz; and TR is Tmax. Tmax is a motor output torque limit value; 2Mz is the required yaw torque.

The above torque distribution strategy in normal driving state drives the anti-skid control stage

The differential steering vehicle takes the motor as an actuator, the response speed of the motor is high, and the principle that the change of the motor moment and the switching are not violent in the process of torque distribution is met as far as possible so as to avoid the phenomenon of vehicle buffeting.

And simultaneously setting working conditions of the driving antiskid module to be limited:

a)20km/h is the threshold value for starting drive antiskid and coordination control,

b) when the vehicle runs straight, the threshold value is that the scratch rate exceeds Slimit (for example, 25%); the exit threshold slip rate is less than S0 (example 15%);

c) turning: when the differential steering vehicle is steered, the tires inevitably generate larger slippage, the threshold value during steering is that the rowing rate exceeds Slimitt (for example 65%), and the exit threshold value is that the rowing rate is less than S0 (for example 50%);

calculating the current slip rate Si of each wheel in real time, comparing the current slip rate Si with the threshold slip rate Slimit and S0 under the current working condition, judging whether the wheels slip or not, and starting driving anti-slip control if the wheels slip; and performing PID (proportion integration differentiation) adjustment in real time according to the change rate of the difference between the current slip rate and the set slip rate S0 to obtain a correction torque, and generating a difference between the correction torque and the calculated torque. At this time, if the vehicle is in a straight-ahead state, the difference between the correction torque and the calculated torque can cause the left and right wheels to generate yaw torque, which is contrary to the non-steering requirement of the driver; if the vehicle is in a turning state, the yaw torque changes, and the driver's steering demand is also not satisfied. A new distribution of torque from wheel to wheel is required.

In addition, in step 3, if slipping occurs and the driving condition is determined to be straight driving, the torque difference generated by the slipping correction torque and the calculated torque is preferentially compensated by the non-slipping wheels on the same side, and when the wheels on the same side cannot be completely compensated, the wheel on the other side is compensated to ensure that the sum TL 'of the left wheel torque after torque correction is equal to the sum TR' of the right wheel torque after torque correction and the torque direction is unchanged.

In addition, in step 3, if the slip occurs and the driving condition is judged to be straight driving, the straight driving comprises forward gear straight driving and reverse gear straight driving, and the torque compensation principle is the same when the forward gear straight driving and the reverse gear straight driving are performed;

when the straight line driving is the forward gear straight line driving, the concrete torque compensation principle is as follows:

defining: calculating a torque Ti, wherein the corrected torque Ti ' is a slip wheel correction torque deviation Δ Ti ' according to a torque correction principle Ti ' >0, and the non-slip wheel surplus torque is Δ Ti, wherein i is 1, 2, 3, 4, and i is 1 denotes a front left wheel, i is 2 denotes a front right wheel, i is 3 denotes a rear left wheel, and i is 4 denotes a rear right wheel;

(1) the principle of torque compensation is the same when the single wheel skids, and when the left front wheel skids, the principle of torque compensation is as follows:

when Δ T2> Δ T1'; the left rear wheel correction torque is T2+ Δ T1'; the torque of each wheel is as follows:

T1′；T2+ΔT1′；T3；T4；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

when Δ T2<Δ T1'; the torque of the non-slipping wheel on the same side cannot be completely compensated, and the compensation value is delta T2; the torque compensation value required by the opposite side is delta T2-delta T1'; getThe torque of each wheel is as follows:

T1′；T2+ΔT2；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

(2) the torque compensation principle is the same when the two wheels on the same side slip, and when the two wheels on the left side slip, the torque compensation principle is taken

The torque of each wheel is as follows:

T1′；T2′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

(3) the principle of torque compensation is the same when the two wheels on different sides slip, and when the left front wheel and the right front wheel slip, the torque compensation principle is taken

If it is notThe wheel torque distribution is then:

T1′；T3′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

if it is notThe wheel torque distribution is then:

T1′；T2+ΔT2；T3′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

if it is notThe wheel torque distribution is then:

T1′；T3′；T4+ΔT2；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

(4) the principle of torque compensation is the same when three wheels slip, and when i equals to 2, 3 and 4, the torque compensation is taken

If it is notThe wheel torque distribution is then:

T1+ΔT1；T2′，T3′，T4′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

if it is notThe wheel torque distribution is then:

T2′，T3′，T4′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

(5) when the four wheels slip, take

If it is notThe wheel torque distribution is then:

T3′；T4′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

if it is notThe wheel torque distribution is then:

T1′；T2′；

the above four sets of values correspond to the cases where i is 1, 2, 3, and 4, respectively;

in addition, in step 3, if no slip occurs and the driving condition is determined to be straight driving, the torque is proportionally distributed to the motors on the two sides according to the driver driving torque demand TD, and the distribution formula is as follows:

wherein TD is the calculated total torque; TR is the sum of the right wheel torques; TL is the sum of left wheel torques.

In addition, in step 3, if no slip occurs and the driving condition is determined as steering, and TR is less than or equal to Tmax, in order to satisfy the yaw torque without affecting the acceleration demand of the driver, the torque distribution formula is:

wherein TD is the calculated total torque; TR is the sum of the right wheel torques; TL is the sum of left wheel torques; mz is yaw torque demand; tmax is the motor output torque limit.

In step 3, if the slip occurs and the driving condition is determined as steering, and TR > Tmax, the torque distribution formula is as follows:

TL＝Tmax-2Mz；

TR＝Tmax；

wherein TR is the sum of the right wheel torques; TL is the sum of left wheel torques; mz is yaw torque demand; tmax is a motor output torque limit value; the torque of the right wheel is ensured to be greater than 0 when the forward gear rotates left, and the torque of the left wheel is ensured to be greater than 0 when the forward gear rotates right; ensuring that the torque of the right wheel is less than 0 when the vehicle is in reverse gear and left-turning; ensuring that the torque of a left wheel is less than 0 when the vehicle is in reverse gear and turns right; the torque distribution is similar to straight running.

On the basis of PID adjustment, the torque reduction amount of the corrected torque of the slipping wheel is distributed to other wheels for torque compensation, so that the driving intention of a driver is realized to the maximum extent, and the driving anti-slipping effect, the vehicle operation stability and the safety are greatly improved.

The invention also provides a four-wheel steering mechanism-free distributed drive automobile antiskid control device, which comprises:

the driving condition judging module is used for judging whether the driving condition is straight driving or steering according to the steering angle of the steering wheel and the gear information of the gearbox monitored in real time;

the slip judging module is used for calculating the current slip rate Si of each wheel in real time, comparing the current slip rate Si with the threshold slip rate S0 under the current driving working condition, judging whether the wheels slip or not, judging that slip occurs when the Si is larger than or equal to S0, and starting driving anti-slip control if the wheels slip; PID adjustment is carried out in real time according to the change rate of the difference between the current slip rate and the set slip rate S0 to obtain a correction torque, and the correction torque and the calculated torque generate a difference at the moment;

a torque redistribution module: and distributing the torque reduction amount after the wheel torque correction of the slipping to other wheels for torque compensation, so that the driving intention of the driver is realized to the maximum extent.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in the present application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships are changed accordingly.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.