A regenerative braking torque dynamic allowable boundary control method and system

Abstract

The application discloses a kind of regenerative braking torque dynamic allowable boundary control method and system, the total braking torque and wheel speed of independent drive wheel i are measured, and the current measurement value of the adhesion torque of independent drive wheel i is estimated;According to the total braking torque and the current measurement value of adhesion torque of independent drive wheel i, total braking torque time series and adhesion torque time series are updated in combination with historical observation value;Adhesion limit is determined according to the total braking torque time series and adhesion torque time series obtained;Based on adhesion limit, the dynamic allowable boundary of braking torque is calculated, and the dynamic allowable boundary value is obtained;Dynamic allowable boundary value is used as limiting amplitude, and the output of total braking force is limited, to realize regenerative braking torque dynamic allowable boundary control.The existing problem that braking safety control method based on slip rate is difficult to apply in independent drive vehicle is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of vehicle control, and particularly relates to a regenerative braking torque dynamic allowable boundary control method and system. BACKGROUND

[0002] Online accurate knowledge of the adhesion limit is crucial to braking safety and stability. The adhesion limit value is different under different road conditions and vehicle states. The anti-lock braking system (ABS) system cannot know the adhesion limit, so the braking slip ratio is maintained at a small constant (such as slip ratio = 0.1) during emergency braking, which cannot achieve the best adhesion utilization of the changing road surface, and the point-by-point hydraulic braking action makes the emergency braking process shake violently and the braking feeling is poor. Based on accurate adhesion limit knowledge, under the continuous and accurate adjustment of the regenerative braking system, the safety and comfort of braking on low adhesion road surface can be greatly improved.

[0003] In existing researches, the regenerative braking system is researched for improving regenerative efficiency, and most of the modeling and analysis are static and steady-state ideas, and the influencing factors are generally modeled as constant static constraint conditions. In actual braking process, the action range of each wheel regenerative braking system is jointly affected by many factors, showing dynamic and time-varying characteristics. The static modeling and analysis method is not conducive to the safety and energy efficiency of the regenerative braking system. Therefore, analyzing and revealing the dynamic allowable boundary of the regenerative braking system is a key problem that has not been deeply explored and answered in existing researches, and it is of great significance to tap the performance limit of safety and energy efficiency improvement of the regenerative braking system.

[0004] Improving the operating energy efficiency is an important direction for the development of new energy vehicles. The regenerative braking system (RBS) can realize braking energy recovery, which is one of the most effective ways to improve energy efficiency. The vehicle braking system is also a key system for safe driving, and the safety must be fully considered during braking, especially in complex adhesion road conditions or emergency braking situations.

[0005] The distributed electric drive vehicle is a vehicle with independent driving capability of each wheel, and each wheel can be independently applied by the hub motor to provide more accurate and faster regenerative braking force than hydraulic braking force, so as to enhance the safety of the vehicle under complex dynamic road adhesion conditions and improve the efficiency of full-wheel braking energy recovery. The motor can provide fast and accurate electromagnetic braking force, and when it cannot provide sufficient braking force under some conditions (such as high speed, heavy load, and emergency braking), the hydraulic mechanical braking system can be supplemented. The system with the joint action of the two kinds of braking forces constitutes a hybrid braking system (HBS).

[0006] However, the regenerative braking system of the distributed electric drive vehicle is a complex electromechanical coupling system, involving the dynamic allowable boundary problem of each wheel regenerative braking force under complex road conditions. The existing technology cannot solve the problem of accurate and rapid state recognition of independent drive wheels under complex and uncertain road conditions. The high dynamic characteristics of the system make the regenerative braking range of each independent drive motor present dynamic time-varying characteristics, that is, the allowable boundary of regenerative braking force is affected by dynamic changes in road conditions, vehicle state, etc. Real-time determination of the regenerative braking allowable boundary of each wheel is the key to fully exert the potential of regenerative braking.

[0007] The braking safety of the distributed electric drive vehicle involves two aspects: one is to reasonably distribute the braking forces of the front and rear axles to avoid the rear wheels from braking first; the other is to reasonably control the braking torque of each wheel to avoid the adhesion force exceeding the adhesion limit.

[0008] The load transfer of the front and rear axles caused by the vehicle braking deceleration is an important factor affecting braking safety. The load transfer causes the normal force of the front and rear axles to change (the normal force of the front axle increases and that of the rear axle decreases during braking), resulting in different maximum adhesion forces of the front and rear axles. Therefore, the braking forces of the front and rear axles must be reasonably distributed to avoid the wheels from reaching the adhesion limit and causing the vehicle to lose stability. For the problem of how to reasonably distribute the braking forces of the front and rear axles, the existing technology can distribute the braking forces based on ideal braking force distribution curves, ECE regulation curves, etc. However, the above-mentioned technology does not consider the adhesion coefficient recognition in braking distribution, and is generally only suitable for regular braking situations.

[0009] The regenerative / hydraulic braking distribution determines the allowable boundary of regenerative braking force according to the vehicle state and the adhesion limit state of the road surface, and maximizes the use of regenerative braking force. The complex diversity and uncertainty of tire-road adhesion characteristics are also important factors affecting braking safety. The adhesion coefficient-slip ratio curve shape and peak point of different tire-road contact conditions are different, making the recognition and maximum adhesion utilization of each wheel adhesion limit challenging. For the adhesion limit recognition and control problem under complex road contact conditions, the traditional ABS keeps the braking slip ratio at a fixed value, which cannot adapt to the dynamic adhesion limit of the changing road surface. The existing scheme considers the changing adhesion coefficient and improves the braking force distribution control law, but it is difficult to choose a suitable adjustment curve. The use of Lagrange interpolation method to estimate the peak adhesion coefficient and optimal slip ratio of the current road surface is conducive to fully utilizing the adhesion limit of the changing road surface and improving the braking performance. However, the above-mentioned existing methods mostly recognize the adhesion state through the slip ratio-adhesion coefficient curve, but the calculation of slip ratio requires accurate vehicle speed and wheel speed signals, which are difficult to obtain in a distributed drive vehicle, and the bandwidth and accuracy of wheel speed are not high, making the bandwidth and accuracy of the sensing system unable to match the control system.

[0010] Existing defects:

[0011] (1) The prior art generally uses slip ratio as the adhesion state, and its calculation depends on accurate high-bandwidth wheel speed and vehicle speed signals. In a distributed drive vehicle, it is difficult to obtain an accurate vehicle speed signal, so the slip ratio cannot be accurately calculated, and the method based on the slip ratio cannot meet the high-bandwidth and high-precision requirements of the motor braking force.

[0012] (2) The distributed drive vehicle can fully utilize the braking adhesion limit of each wheel, but it depends on the real-time accurate identification of the optimal adhesion limit. However, the optimal adhesion working point under complex road adhesion conditions has uncertainty and unknownness, and the problem of rapid adhesion identification in regenerative braking has not been well solved. The prior art only does fixed constant processing, and cannot realize dynamic identification and control of the regenerative braking force allowable boundary, so it cannot fully utilize the maximum adhesion capacity of each wheel, affecting the braking effect. SUMMARY

[0013] The technical problem to be solved by the present application is to provide a regenerative braking torque dynamic allowable boundary control method and system to solve the technical problem of accurate and rapid state identification of an independently driven wheel under complex and uncertain road conditions.

[0014] The application adopts the following technical solutions:

[0015] A regenerative braking torque dynamic allowable boundary control method, comprising the following steps:

[0016] Measuring the total braking torque and wheel speed of an independently driven wheel i, and estimating the current measurement value of the adhesion torque of the independently driven wheel i;

[0017] According to the total braking torque and the current measurement value of the adhesion torque of the independently driven wheel i, and combining the historical observation value to update the total braking torque time sequence and the adhesion torque time sequence;

[0018] Determining the adhesion limit according to the obtained total braking torque time sequence and adhesion torque time sequence;

[0019] Calculating the braking torque dynamic allowable boundary based on the adhesion limit to obtain a dynamic allowable boundary value;

[0020] Taking the dynamic allowable boundary value as an amplitude limit to limit the output of the total braking force, and realizing regenerative braking torque dynamic allowable boundary control.

[0021] Preferably, the total braking torque is the sum of the regenerative braking torque and the hydraulic braking torque.

[0022] Preferably, the current measurement value of the adhesion torque of the independently driven wheel i is :

[0023]

[0024] wherein, is the total braking torque applied to the independently driven wheel i, is the moment of inertia of the wheel, is the measured wheel speed signal.

[0025] Preferably, the total braking torque time series is:

[0026] {T b k-n , T b k-n+1 , …, T b k-1 , T b k}

[0027] The adhesion torque time series is:

[0028] {T d k-n , T d k-n+1 , …, T d k-1 , T d k}

[0029] wherein n represents the number of historical time instants and k represents the current time instant.

[0030] Preferably, the historical observations comprise total braking torque measurements and adhesion torque estimations of a number of past historical time instants of the same time interval.

[0031] Preferably, determining the adhesion limit is specifically:

[0032] identifying a monotonicity of the total braking torque time series;

[0033] identifying a monotonicity of the adhesion torque when the total braking torque is monotonically increasing;

[0034] identifying a peak point of a convex function of the adhesion torque sequence, and recording the adhesion torque at this time instant as a critical adhesion torque T d_max , and the braking torque at this time instant as a critical braking torque T b_max .

[0035] Preferably, identifying a monotonicity of the adhesion torque is specifically:

[0036] outputting an adhesion stable result when the adhesion torque sequence is monotonically increasing;

[0037] outputting an adhesion unstable result when the adhesion torque sequence is monotonically decreasing;

[0038] When the adhesion torque sequence is not monotonically increasing or decreasing, and presents a convex function feature, the output adhesion critical stability result is outputted.

[0039] Preferably, the critical adhesion torque T d_max is the maximum adhesion torque under the current tire-pavement contact condition.

[0040] Preferably, the dynamic allowable boundary value is calculated as follows:

[0041]

[0042] wherein, is the braking torque dynamic allowable boundary, is the critical adhesion torque, is the torque dynamic allowable difference value, is an adjustment coefficient.

[0043] In a second aspect, an embodiment of the present application provides a regenerative braking torque dynamic allowable boundary control system, comprising:

[0044] a measurement module, which measures the total braking torque and the wheel speed of the independent drive wheel i, and estimates the current measurement value of the adhesion torque of the independent drive wheel i;

[0045] a sequence module, which updates the total braking torque time sequence and the adhesion torque time sequence according to the total braking torque and the current measurement value of the adhesion torque of the independent drive wheel i, in combination with historical observation values;

[0046] a calculation module, which determines the adhesion limit according to the obtained total braking torque time sequence and adhesion torque time sequence;

[0047] a boundary module, which calculates the braking torque dynamic allowable boundary based on the adhesion limit, and obtains the dynamic allowable boundary value;

[0048] a control module, which takes the dynamic allowable boundary value as an amplitude limit, limits the output of the total braking force, and realizes the regenerative braking torque dynamic allowable boundary control.

[0049] In a third aspect, a computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor realizes the steps of the above-mentioned regenerative braking torque dynamic allowable boundary control method when executing the computer program.

[0050] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium comprising a computer program, and the computer program realizes the steps of the above-mentioned regenerative braking torque dynamic allowable boundary control method when executed by a processor.

[0051] In a fifth aspect, a chip is provided, which includes a memory, a processor, and a computer program stored in the memory and capable of running on the processor, and the processor implements the steps of the regenerative braking torque dynamic allowable boundary control method when the computer program is executed.

[0052] In a sixth aspect, an electronic device is provided, which includes a computer program, and the computer program implements the steps of the regenerative braking torque dynamic allowable boundary control method when the electronic device executes the computer program.

[0053] Compared with the prior art, the present application has at least the following beneficial effects:

[0054] The regenerative braking torque dynamic allowable boundary control method only needs to use the total braking force of the wheel i, the wheel speed and other measurement signals, which are easy to measure in the independent drive wheels of the distributed drive vehicle; the vehicle speed does not need to be measured (the accurate vehicle speed can generally be replaced by the speed of the follow-up wheel of the vehicle, but there is no follow-up wheel in the distributed drive vehicle, so the accurate vehicle speed cannot be obtained by this method), so the problem of calculating the slip rate is avoided: during braking, the slip rate = (vehicle speed - wheel speed) / vehicle speed; for the wheel i, when the total braking torque (including the sum of the motor braking torque and the hydraulic braking torque) applied to the wheel increases, if the adhesion torque also increases (the adhesion torque is the longitudinal friction torque generated by the tire-road contact, which is the braking torque that slows down the vehicle), it indicates that the friction braking torque between the vehicle and the ground is also increasing, which is a stable braking situation; otherwise, it indicates that the friction braking torque between the vehicle and the ground is decreasing, and the wheel tends to rapidly slow down or even lock, which is an unstable braking situation; by obtaining the time series of the total braking torque and the adhesion torque in the same time span, the above behavior characteristics can be more accurately identified, so as to accurately identify whether the adhesion state is stable; in particular, when the adhesion torque presents a convex characteristic of first increasing and then decreasing in the time series, it indicates that the time series has captured the dynamic process of the adhesion torque reaching the maximum limit value and then entering the unstable adhesion region, and the maximum adhesion torque is further searched from the time series, which represents the size of the peak adhesion limit of the tire-road under the current dynamic conditions; the problem that the existing method cannot dynamically identify the maximum adhesion limit is solved, and the identified adhesion limit is further used to determine the current braking torque dynamic allowable boundary, i.e., the total braking force allowed to be applied, which can limit the total braking force from being too large to cause the wheel to lock, and fully utilize the maximum adhesion limit of the dynamic tire-road, i.e., ensure braking safety while enhancing braking effect.

[0055] Further, by setting time series, the total braking force behavior process characteristics in a period of time can be described, and the behavior characteristics of the braking force demand can be accurately reflected, such as the time series of the continuously increasing braking torque, which indicates the continuously increasing braking intensity demand of the driver. In addition, by flexibly adjusting the number of elements of the time series and the time interval between adjacent time points in the time series, the behavior span represented by the time series can be flexibly adjusted. This method provides the ability to adapt to different speeds, for example, at high speed, the time series span is short, so that the behavior change characteristics can be identified in real time; at low speed, the time series span can be long.

[0056] Further, the time series of the adhesion torque is consistent with the span of the total braking torque time series, and the dynamic change behavior characteristics of the adhesion torque can be more accurately observed, and the identification accuracy is improved.

[0057] Further, the monotonicity of the total braking torque time series is identified: if the total braking torque decreases, it means that the braking force demand applied by the driver decreases, at this time, it represents the behavior of the driver to actively reduce the braking intensity, which is a stable adhesion trend, and therefore does not need to be processed; if the total braking torque increases, it means that the braking force demand applied by the driver increases, which represents the behavior of the driver to continuously increase the braking intensity; at this time, the change characteristics of the adhesion torque need to be further identified, so as to identify whether the adhesion torque also increases stably, which can be identified by the monotonicity of the adhesion torque: the monotonic increase of the adhesion torque time series means that the adhesion force increases, which is a stable adhesion braking state; otherwise, it is an unstable adhesion braking state; when it first increases and then decreases, it represents that the maximum adhesion torque peak value is first reached and then reduced. Therefore, by this way, the adhesion limit (the adhesion limit is the maximum ground adhesion force that the wheel i can obtain under the current road and current vehicle state, which is also the maximum friction force that can slow down the vehicle) can be determined. The maximum adhesion capacity of the ground can be fully utilized to enhance the adhesion braking capacity, and the maximum braking performance can be obtained in low adhesion road braking or emergency braking.

[0058] Further, the adhesion stability in the time series span is accurately judged according to the monotonicity of the adhesion torque. The advantage is that the adhesion state of the wheel i in the braking process can be obtained in real time. When unstable adhesion occurs, the control system can further actively reduce the applied braking force, so that the wheel i reacquires a larger adhesion torque, and the braking safety is ensured.

[0059] Further, a dynamic allowable boundary value Tb_adm is set, so that the total braking force applied is slightly greater than the maximum adhesion torque, and less than the total braking torque when the maximum adhesion torque occurs. The advantage of this is that braking safety can be ensured, and the part exceeding the maximum adhesion torque can be used to provide the wheel i's own deceleration. According to the wheel dynamics equation, it can be found that only when the wheel deceleration is 0 (steady state), the total braking torque is equal to the adhesion torque; and in the dynamic braking process, the wheel deceleration is generally not 0, at this time when the adhesion torque is the maximum adhesion torque, the total braking torque amplitude applied is generally slightly greater than the maximum adhesion torque, to provide additional wheel deceleration until the wheel and vehicle stop. The α is an adjustment coefficient, which provides a certain adjustable ability, and provides additional wheel braking force for its deceleration until the wheel and vehicle stop.

[0060] It can be understood that the beneficial effects of the above-mentioned second aspect to the sixth aspect can be referred to the related description in the above-mentioned first aspect, which will not be repeated here.

[0061] In summary, the present application does not depend on the slip rate, only needs the total braking force and the wheel speed, is easy to implement in a distributed drive vehicle; can identify the maximum adhesion limit under dynamic conditions, and fully utilize the dynamic maximum adhesion capacity of the tire-road surface; can identify the adhesion stability state, and obtain whether the braking wheel is in a stable adhesion state, to avoid the braking wheel from being locked.

[0062] The technical solutions of the present application will be further described in detail below with the aid of the accompanying drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0063] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0064] Figure 1 The schematic diagram of the method of the present application is shown in the figure;

[0065] Figure 2 The torque change characteristic diagram which is monotonically increasing is shown in the figure;

[0066] Figure 3 The torque change characteristic diagram which is monotonically decreasing is shown in the figure;

[0067] Figure 4 The torque change characteristic diagram which presents the convex function change characteristic is shown in the figure;

[0068] Figure 5 The curve diagram of the adhesion torque and the slip rate under certain tire-road surface conditions is shown in the figure;

[0069] Figure 6 a schematic diagram of a computer device according to an embodiment of the present application;

[0070] Figure 7 a block diagram of an electronic device according to an embodiment of the present application;

[0071] Fig. 8 is a braking result curve diagram of the prior slip rate control (set value = 0.2), wherein Fig. 8(a) is a vehicle speed and wheel speed control simulation diagram, and Fig. 8(b) is a braking distance simulation diagram;

[0072] Fig. 9 is a braking result curve diagram of the method of the present application, wherein Fig. 9(a) is a vehicle speed and wheel speed control simulation diagram, and Fig. 9(b) is a braking distance simulation diagram. DETAILED DESCRIPTION

[0073] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of the present application.

[0074] In the description of the present application, it should be understood that the terms "comprising" and "including" indicate the presence of described features, integers, steps, operations, elements, and / or components, but do not exclude one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0075] It should also be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and the appended claims of the present application, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0076] It should be further understood that the term "and / or" used in the specification and the appended claims of the present application means any combination of one or more of the associated listed items and all possible combinations thereof, and includes these combinations, for example, A and / or B can represent three cases of A alone, A and B together, and B alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0077] It should be understood that, although the terms first, second, third, etc. can be employed in describing the preset ranges, etc. in the embodiments of the present application, the preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from each other. For example, the first preset range can also be referred to as the second preset range, and similarly, the second preset range can also be referred to as the first preset range, without departing from the scope of the embodiments of the present application.

[0078] Depending on the context, the word "if" as used herein can be interpreted to mean "when" or "while" or "in response to determining" or "in response to detecting." Similarly, the phrase "if it is determined" or "if [a stated condition or event] is detected" can be interpreted to mean "upon being determined," or "in response to determining" or "upon detecting [the stated condition or event]," or "in response to detecting [the stated condition or event]."

[0079] Various structural diagrams according to the disclosed embodiments of the present application are shown in the accompanying drawings. These diagrams are not drawn to scale, in which certain details are exaggerated for the purpose of clarity, and certain details can be omitted. The shapes of various regions, layers shown in the diagrams, and their relative sizes and positional relationships are only exemplary, and in actuality, they can deviate due to manufacturing tolerances or technical limitations, and a person skilled in the art can additionally design regions / layers with different shapes, sizes, relative positions according to actual needs.

[0080] The present application provides a regenerative braking torque dynamic allowable boundary control method, which maximizes the utilization of wheel adhesion under the premise of safety, thereby improving braking efficiency; by directly measuring and analyzing torque, it is more flexible and accurate to adapt to various driving conditions and vehicle states, especially on distributed drive vehicles with complex drive configurations; in addition, the method enhances the stability and safety of the vehicle in emergency braking, which helps to reduce braking distance and avoid collisions.

[0081] Embodiment 1

[0082] Please refer to Figure 1 The regenerative braking torque dynamic allowable boundary control method of the present application comprises the following steps:

[0083] S1, for an independently driven wheel i, measuring the total braking torque T of the independently driven wheel i bi ;

[0084] The total braking torque includes the sum of the regenerative braking torque and the hydraulic braking torque.

[0085] The size of the regenerative braking torque is obtained by the motor drive system, and the size of the hydraulic braking torque can be obtained by the hydraulic braking system.

[0086] When the braking torque demand is small, i.e. the braking force demand is less than the maximum braking force the motor can provide, the total braking force is provided by the motor regenerative braking torque;

[0087] When the braking torque demand is large, i.e. the braking force demand is greater than the maximum braking force the motor can provide, or the motor cannot provide enough regenerative braking force, the hydraulic braking torque is used to supplement.

[0088] S2, measure the wheel speed of the independent drive wheel i, and estimate the adhesion torque of the independent drive wheel i;

[0089] The adhesion torque of the independent drive wheel i is the friction torque generated by the contact between the tire of the independent drive wheel i and the road surface; during braking, this friction torque is the friction that slows down the vehicle.

[0090] The adhesion torque cannot be directly measured, and the adhesion torque can be estimated by other measurable parameters.

[0091] According to the wheel speed, the total braking torque applied, the adhesion torque observation equation is designed to estimate the adhesion torque:

[0092]

[0093] wherein, is the estimated adhesion torque of the wheel, is the total braking torque applied to the wheel, is the rotational inertia of the wheel, is the measured wheel speed signal.

[0094] The above estimation equation is designed using the tire dynamics equation model, in order to make the adhesion estimation more accurate, the measured signal and First, filter the noise, and then send it to the adhesion torque estimator.

[0095] S3, update the total braking force and adhesion torque time series according to the current measurement and historical observation of each total braking torque and adhesion torque;

[0096] The historical observation includes the total braking torque measurement and the adhesion torque estimation of several past historical time intervals.

[0097] The total braking torque time series composed of the current measurement and the historical observation is:

[0098] {T b k-n , T b k-n+1 , …, T b k-1 , T bk}

[0099] wherein n represents the number of historical time, k represents the current time. The time interval between k time and k-1 time can be flexibly adjusted, for example, set to 20 milliseconds.

[0100] The time series of the adhesion torque composed of the current estimated value and the historical estimated value is:

[0101] {T d k-n , T d k-n+1 , …, T d k-1 , T d k}

[0102] wherein n represents the number of historical time, k represents the current time. The time interval between k time and k-1 time can be flexibly adjusted, for example, set to 20 milliseconds.

[0103] The time interval of the total braking torque time series and the adhesion torque time series, the number of historical time should be kept the same, so as to ensure that the time span of the two time series is equal.

[0104] S4, according to the total braking torque time series, the time series of the adhesion torque, according to the criterion to determine the adhesion limit;

[0105] S401, identify the monotonicity of the total braking torque time series. If the total braking force is monotonically increasing, go to step S402; otherwise (other change characteristics), end, return to step S401;

[0106] Please refer to Figure 2 , the torque change characteristic of monotonically increasing.

[0107] S402, at this time, the total braking torque is monotonically increasing, and then identify the monotonicity of the adhesion torque;

[0108] If the adhesion torque sequence is monotonically increasing, output the adhesion stable result; end, return to step S401;

[0109] If the adhesion torque sequence is monotonically decreasing, output the adhesion unstable result; end, return to step S401;

[0110] If the adhesion torque sequence is not monotonically increasing or decreasing, and presents the convex function characteristics, output the adhesion critical stable result, go to the next step S403.

[0111] Please refer to Figure 3, the monotonic decreasing torque variation characteristic indicates that the adhesion torque (longitudinal tire force) generated by the wheel i and the road surface is monotonically decreasing in the case of the total braking torque of the wheel i monotonically increasing, which indicates that the tire force of the vehicle braking generated by the tire-road surface friction is decreasing, which is an unstable tire-road surface adhesion state. By the time sequence of the adhesion torque as shown in Figure 3 , the dynamic variation behavior process characteristic of the adhesion torque can be more accurately obtained, and thus the adhesion stability state of the current wheel can be more accurately identified.

[0112] Please refer to Figure 4 , the torque variation characteristic of the convex function variation characteristic indicates that the adhesion torque (longitudinal tire force) generated by the wheel i and the road surface first increases to a maximum value and then starts to decrease in the case of the total braking torque of the wheel i monotonically increasing. This indicates that the tire force of the vehicle braking generated by the tire-road surface friction reaches the maximum adhesion limit value in this period of time, and the maximum adhesion limit value is the maximum adhesion capability of the tire-road surface under the current dynamic condition, which also represents the maximum friction force that can be provided by the wheel i to brake the vehicle. By the time sequence of the adhesion torque as shown in Figure 3 , the dynamic variation behavior process characteristic of the adhesion torque can be more accurately obtained, and thus the adhesion stability state of the current wheel can be more accurately identified.

[0113] S403, identify the peak point of the convex function of the adhesion torque sequence, and record the adhesion torque at this time as the critical adhesion torque T d_max , and the braking torque at this time is the critical braking torque T b_max .

[0114] The critical adhesion torque T d_max is the maximum adhesion torque under the current tire-road surface contact condition, which represents the maximum adhesion limit capability under the current dynamic condition considering the vehicle state and the road surface condition. If the applied braking torque exceeds this maximum adhesion torque, the wheel may be locked.

[0115] Please refer to Figure 5 , the adhesion torque and slip rate relationship curve under a certain tire-road surface condition. As the braking force applied to the wheel increases, the adhesion torque increases rapidly (corresponding to a stable adhesion state, at this time the adhesion torque increases continuously, and the vehicle braking capability increases continuously), and then decreases rapidly after reaching the peak value (corresponding to an unstable adhesion state, at this time the adhesion capability decreases continuously, and the slip rate increases rapidly, and tends to lock when the slip rate becomes 1, and the wheel is completely locked). At k-2, the working point corresponds to the maximum adhesion torque, and the adhesion torque identified at this time can represent the maximum adhesion capability limit under the current tire-road surface condition. By the time sequence of the adhesion torque as shown in Figure 5The maximum adhesion torque can be more accurately captured when k-4 to the current time k.

[0116] S5, calculating a dynamic allowable boundary of braking torque;

[0117] S501, calculating a dynamic allowable difference of torque;

[0118] The dynamic allowable difference of torque As follows:

[0119]

[0120] The dynamic allowable difference of torque represents the total braking force of the wheel corresponding to the current maximum adhesion torque, which is generally Higher than This part of the difference torque can be used to provide the wheel's own deceleration.

[0121] S502, determining a dynamic allowable boundary value ;

[0122] The dynamic allowable boundary value The calculation is as follows:

[0123]

[0124] Wherein, is the dynamic allowable boundary of braking torque, is the critical adhesion torque, is the dynamic allowable difference of torque, is the adjustment coefficient, which can be adjusted according to the actual situation.

[0125] The size of the adjustment coefficient can appropriately adjust the size of the braking force, and can be set according to the actual experimental situation. Since the vehicle state is in real-time dynamic change, the adjustment of the coefficient provides the ability to adapt to dynamic changes. At the same time, the size of is not more than 1, which ensures that the part of the braking force exceeding the peak adhesion force is less than the dynamic allowable difference of torque, and guarantees the safety and stability of braking.

[0126] S6, taking the dynamic allowable boundary value as an amplitude limit to limit the output of the total braking force.

[0127] Those skilled in the art can understand that various aspects of the present application can be implemented as a system, method or program product. Therefore, various aspects of the present application can be specifically implemented in the following forms: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or an implementation combining hardware and software aspects, which can be collectively referred to as "circuit", "module" or "platform" here.

[0128] Embodiment 2

[0129] The application provides a regenerative braking torque dynamic allowable boundary control system, which can be used for implementing the regenerative braking torque dynamic allowable boundary control method.

[0130] The measurement module measures the total braking torque and the wheel speed of the independent driving wheel i, and estimates the current measurement value of the adhesion torque of the independent driving wheel i.

[0131] The sequence module updates the total braking torque time sequence and the adhesion torque time sequence according to the total braking torque and the current measurement value of the adhesion torque of the independent driving wheel i in combination with the historical observation value.

[0132] The calculation module determines the adhesion limit according to the obtained total braking torque time sequence and adhesion torque time sequence.

[0133] The boundary module calculates the braking torque dynamic allowable boundary based on the adhesion limit, and obtains the dynamic allowable boundary value.

[0134] The control module limits the output of the total braking force by taking the dynamic allowable boundary value as an amplitude limit, and realizes the regenerative braking torque dynamic allowable boundary control.

[0135] Embodiment 3

[0136] The application provides a terminal device, which comprises a processor and a memory for storing a computer program, wherein the computer program comprises program instructions, and the processor is used for executing the program instructions stored in the computer storage medium. The processor can be a central processing unit (CPU), and can also be other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components and the like, which are the computing core and control core of the terminal, and are suitable for implementing one or more instructions, and are specifically suitable for loading and executing one or more instructions to implement a corresponding method flow or a corresponding function; the processor in the embodiment of the application can be used for the operation of the regenerative braking torque dynamic allowable boundary control method, comprising:

[0137] The total braking torque and the wheel speed of the independently driven wheel i are measured, and the current measurement value of the adhesion torque of the independently driven wheel i is estimated; the total braking torque time sequence and the adhesion torque time sequence are updated according to the total braking torque and the current measurement value of the adhesion torque of the independently driven wheel i in combination with historical observation values; the adhesion limit is determined according to the obtained total braking torque time sequence and adhesion torque time sequence; the dynamic allowable boundary of the braking torque is calculated based on the adhesion limit, and the dynamic allowable boundary value is obtained; the dynamic allowable boundary value is taken as an amplitude limiting, the output of the total braking force is limited, and the regenerative braking torque dynamic allowable boundary control is realized.

[0138] Please refer to Figure 6 The terminal device is a computer device, and the computer device 60 of the embodiment comprises a processor 61, a memory 62 and a computer program 63 stored in the memory 62 and capable of running on the processor 61, wherein the computer program 63 realizes the regenerative braking torque dynamic allowable boundary control method in the embodiment when executed by the processor 61, and details are not repeated here. Alternatively, the computer program 63 realizes the functions of various models / units in the regenerative braking torque dynamic allowable boundary control system of the embodiment when executed by the processor 61, and details are not repeated here.

[0139] The computer device 60 can be a desktop computer, a notebook computer, a palm computer, a cloud server, and the like. The computer device 60 can include, but is not limited to, a processor 61, a memory 62. Those skilled in the art can understand that Figure 6 The computer device 60 is only an example and does not constitute a limitation on the computer device 60, and can include more or fewer components than shown, or combine certain components, or different components, for example, the computer device can also include an input / output device, a network access device, a bus, and the like.

[0140] The processor 61 can be a central processing unit (CPU), and can also be other general-purpose processors, graphics processing units (GPUs), tensor processing units (TPUs), digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, and the like. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0141] The memory 62 can be an internal storage unit of the computer device 60, such as a hard disk or a memory of the computer device 60. The memory 62 can also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, and the like.

[0142] Further, the memory 62 can include both an internal storage unit and an external storage device of the computer device 60. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0143] Please refer to Figure 7 The terminal device is an electronic device 600, and the electronic device 600 is in the form of a general-purpose computing device. The components of the electronic device can include, but are not limited to, at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including the storage unit 620 and the processing unit 610), a display unit 640, and the like.

[0144] The storage unit stores program codes which can be executed by the processing unit 610, so that the processing unit 610 performs the steps according to various exemplary embodiments of the present application described in the method part of the present specification. For example, the processing unit 610 can perform the steps as shown in Figure 1 the method part of the present specification.

[0145] The storage unit 620 can include a readable medium in the form of volatile storage unit, such as a random access memory (RAM) 6201 and / or a cache memory 6202, and further include a read-only memory (ROM) 6203.

[0146] The storage unit 620 can further include a program / utility 6204 having a set of programs / modules 6205, including an operating system, one or more application programs, other programs, and programmatic modules, each of which can implement aspects of the networks environment, as well as portions of the method described in the method part of the present specification.

[0147] The bus 630 can represent one or more of several types of bus structures, including a storage unit bus or bus controller, a peripheral bus, a graphics acceleration port, a processing unit bus, or a local bus using any of a variety of bus architectures.

[0148] The electronic device 600 can also communicate with one or more external devices 700 such as a keyboard or pointing device, a Bluetooth device, etc.; other devices that enable a user to interact with the electronic device 600; and / or one or more devices that enable the electronic device 600 to communicate with one or more other computing devices. Such communication can be via the input / output (I / O) interface 650. Further, the electronic device 600 can communicate with one or more networks, such as a local area network (LAN), a wide area network (WAN), and / or the public network, such as the Internet, via the network adapter 660. The network adapter 660 can communicate with the other modules of the electronic device 600 via the bus 630. It should be appreciated that although not shown, other hardware and / or software modules could be used in connection with the electronic device 600. These include, but are not limited to, microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data archival storage systems, etc.

[0149] Example 4

[0150] The present application further provides a storage medium, specifically a computer readable storage medium (Memory), which is a memory device in the terminal device, used for storing programs and data. It can be understood that the computer readable storage medium herein can include the built-in storage medium in the terminal device, and of course can also include the expansion storage medium supported by the terminal device, and can be any tangible medium containing or storing programs, which can be used by or in combination with an instruction execution system, device or apparatus. The computer readable storage medium provides a storage space, which stores the operating system of the terminal. Moreover, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, which can be one or more computer programs (including program codes). It should be noted that more specific examples (non-exhaustive list) of the computer readable storage medium herein include: an electrical connection with one or more conductive wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0151] The computer readable storage medium further includes a data signal carried in the baseband or as a part of a carrier wave, in which readable program codes are borne. Such a propagated data signal can take various forms, including but not limited to electro-magnetic signal, optical signal or any suitable combination of the above. The readable storage medium can also be any readable medium other than the readable storage medium, which can send, propagate or transmit programs for use by or in combination with an instruction execution system, device or apparatus. The program codes contained on the readable storage medium can be transmitted by any suitable medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the above.

[0152] The program code for performing the operations of the present application can be written in any combination of one or more programming languages, including an object-oriented programming language such as Java, C++, etc., and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device and partly on a remote computing device or entirely on the remote computing device or server. In the latter scenario, the remote computing device can be connected to the user's computing device through any kind of network, including a local area network (LAN) or a wide area network (WAN), or the remote computing device can be connected to the external computing device (for example, using an Internet service provider to connect to the Internet).

[0153] The one or more instructions stored in the computer readable storage medium can be loaded and executed by the processor to implement the corresponding steps of the method for controlling the dynamic allowable boundary of the regenerative braking torque in the above embodiments; the one or more instructions stored in the computer readable storage medium are loaded and executed by the processor to implement the following steps:

[0154] The total braking torque and the wheel speed of the independently driven wheel i are measured, and the current measurement value of the adhesion torque of the independently driven wheel i is estimated; the total braking torque time sequence and the adhesion torque time sequence are updated according to the total braking torque and the current measurement value of the adhesion torque of the independently driven wheel i in combination with historical observation values; the adhesion limit is determined according to the obtained total braking torque time sequence and adhesion torque time sequence; the dynamic allowable boundary of the braking torque is calculated based on the adhesion limit, and the dynamic allowable boundary value is obtained; the dynamic allowable boundary value is taken as an amplitude limiting, the output of the total braking force is limited, and the dynamic allowable boundary control of the regenerative braking torque is realized.

[0155] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will be a clear and complete description of the technical solutions in the embodiments of the present application in combination with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the accompanying drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0156] The effect of the method of the present application is simulated and compared with the slip ratio control method.

[0157] The slip ratio control method is to adjust the wheel braking force to maintain the slip ratio around a set value; in the simulation, the set value is set to 0.2. In the simulation of the method of the present application, the adjustment coefficient is set to 0.4, which can be adjusted in actual use. If more aggressive braking is desired, the adjustment coefficient is increased ; otherwise, the adjustment coefficient is decreased . In the simulation, the initial vehicle speed and wheel speed are 20 m / s, the road adhesion coefficient is 0.78, the simulation scenario is emergency braking, and the evaluation index is braking distance. The shorter the braking distance, the more fully the road adhesion is utilized.

[0158] The simulation results are as follows:

[0159] Please refer to FIG. 8(a) and FIG. 8(b), the braking distance of the slip ratio control method is 136.5 m, and the braking time is 15.2 s;

[0160] Please refer to Fig. 9 (a) and Fig. 9 (b), the braking distance of the method of the application is 122.7 m, and the braking time is 11.5 s.

[0161] It is illustrated that the method of the application can effectively avoid wheel lock, and the road adhesion utilization rate is higher, the braking effect is better, and the braking distance and time are shorter.

[0162] Please refer to Fig. 8 (a) and Fig. 8 (b), in the simulation, the vehicle speed and wheel speed can be accurately obtained, and then the slip rate state value can be accurately calculated, but in actual application, especially in the distributed drive vehicle, the slip rate of the driving wheel cannot be directly calculated by measuring the vehicle speed and the wheel speed; it is further demonstrated that the method of the application does not need the slip rate to participate in the control, and overcomes the problem that the slip rate is difficult to calculate in the distributed drive vehicle, please refer to Fig. 9 (a) and Fig. 9 (b).

[0163] In summary, the regenerative braking torque dynamic allowable boundary control method and system of the application uses the time sequence of the driving torque and the adhesion torque as the input, can more accurately capture the adhesion stable state under the dynamic change condition, enhances the stable and safe identification ability in the braking process; can dynamically capture the maximum adhesion torque, and uses the dynamic allowable boundary value as the limiting amplitude, can guarantee the braking safety, at the same time, enhances the adhesion ability utilization of each wheel of the distributed drive vehicle, and enhances the braking effect; does not need to calculate the parameters such as the slip rate which are difficult to accurately obtain, and can solve the problem that the existing braking safety control method based on the slip rate is difficult to apply in the independent drive vehicle.

[0164] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional units and modules is exemplified, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or software. In addition, the specific names of the functional units and modules are only for mutual distinction, and do not limit the protection scope of the application. The specific working process of the units and modules in the system can be referred to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0165] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in a certain embodiment can be referred to the related description of other embodiments.

[0166] Those skilled in the art can understand that the units and algorithm steps of each example described in combination with the embodiments disclosed in the present application can be realized in electronic hardware or in combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0167] In the embodiments provided by the present application, it should be understood that the disclosed apparatus / terminal and method can be implemented in other ways. For example, the apparatus / terminal embodiments described above are merely schematic. The division of the modules or units is merely a logical function division, and there can be another division manner in actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed coupling or direct coupling or communication connection between the units can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or in other forms.

[0168] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e. can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0169] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically independently, or two or more units can be integrated into one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0170] The integrated module / unit, if realized in the form of a software function unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on such understanding, all or part of the processes in the above-mentioned embodiment methods can also be completed by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of each method embodiment when executed by a processor. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or some intermediate forms, etc. The computer-readable medium can include any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the computer-readable medium can include or exclude contents according to the requirements of legislation and patent practice in the jurisdiction, for example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0171] The present application is described with reference to flowcharts and / or block diagrams of methods, devices, and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0172] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including instruction devices that implement the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0173] These computer program instructions can also be loaded into a computer or other programmable data processing devices, so that a series of operational steps are performed on the computer or other programmable data processing devices to generate a computer implemented process, so that the instructions executed on the computer or other programmable data processing devices provide a process for implementing the functions specified in the flowchart Figure 1 one flow or multiple flows and / or the functions specified in the block Figure 1 one flow or multiple flows and / or the functions specified in the block

[0174] The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the claims of the present application.

Claims

1. A method of regenerative braking torque dynamic admissible boundary control, characterized in that, The method comprises the following steps: measuring the total braking torque and wheel speed of the independent drive wheel i, and estimating the current measurement value of the adhesion torque of the independent drive wheel i; updating the total braking torque time sequence and the adhesion torque time sequence according to the total braking torque and the current measurement value of the adhesion torque of the independent drive wheel i in combination with historical observation values; determining the adhesion limit according to the obtained total braking torque time sequence and adhesion torque time sequence, specifically as follows: identifying the monotonicity of the total braking torque time sequence; when the total braking torque is monotonically increasing, identifying the monotonicity of the adhesion torque; The peak point moment of the convex function of the adhesion torque sequence is identified, and the adhesion torque at the peak point moment is recorded as a critical adhesion torque T d_max The peak point moment of the convex function of the adhesion torque sequence is identified, and the adhesion torque at the peak point moment is recorded as a critical adhesion torque T b_max ; identifying the monotonicity of the adhesion torque specifically as follows: when the adhesion torque sequence is monotonically increasing, outputting an adhesion stable result; when the adhesion torque sequence is monotonically decreasing, outputting an adhesion unstable result; when the adhesion torque sequence is neither monotonically increasing nor decreasing, and presents a convex function feature, outputting an adhesion critical stable result; Based on the adhesion limit, a dynamic allowable boundary of the braking torque is calculated to obtain a dynamic allowable boundary value, the dynamic allowable boundary value The calculation is as follows: wherein is the dynamic admissible limit of braking torque, is the critical adhesion torque, is the dynamic admissible difference of torque, is the adjustment coefficient; taking the dynamic allowable boundary value as an amplitude limiting, limiting the output of the total braking force, and realizing dynamic allowable boundary control of the regenerative braking torque.

2. The regenerative braking torque dynamic admissible boundary control method according to claim 1, characterized in that, The total braking torque is the sum of the regenerative braking torque and the hydraulic braking torque.

3. The regenerative braking torque dynamic admissible boundary control method according to claim 1, characterized in that, the current measured value of the adhesion torque of the individual drive wheel i is: wherein is the total braking torque applied to the individual driven wheel i, is the moment of inertia of the wheel, is the measured wheel speed signal.

4. The regenerative braking torque dynamic admissible boundary control method according to claim 1, characterized in that, The total braking torque time sequence is: {T b k-n , T b k-n+1 ,..., T b k-1 , T b k} The adhesion torque time sequence is: {T d k-n ,T d k-n+1 ,…,T d k-1 ,T d k} wherein n represents the number of historical time points, and k represents the current time point.

5. The regenerative braking torque dynamic admissible boundary control method according to claim 4, characterized in that, The historical observation values include the total braking torque measurement values and the adhesion torque estimated values of a plurality of past historical time points with the same time interval.

6. The regenerative braking torque dynamic admissible boundary control method according to claim 1, characterized in that, Critical adhesion torque T d_max is the maximum adhesion torque for the current tire-road contact conditions.

7. A regenerative braking torque dynamic allowable boundary control system characterized by, The method comprises the following steps: a measuring module for measuring the total braking torque and wheel speed of the independent drive wheel i, and estimating the current measurement value of the adhesion torque of the independent drive wheel i; a sequence module for updating the total braking torque time sequence and the adhesion torque time sequence according to the total braking torque and the current measurement value of the adhesion torque of the independent drive wheel i in combination with historical observation values; a calculation module for determining the adhesion limit according to the obtained total braking torque time sequence and adhesion torque time sequence, specifically as follows: identifying the monotonicity of the total braking torque time sequence; when the total braking torque is monotonically increasing, identifying the monotonicity of the adhesion torque; The moment of peak value point of the convex function of the adhesion moment sequence is recorded as the critical adhesion moment T d_max The moment of peak value point of the convex function of the adhesion moment sequence is recorded as the critical adhesion moment T b_max ; identifying the monotonicity of the adhesion torque specifically as follows: when the adhesion torque sequence is monotonically increasing, outputting an adhesion stable result; when the adhesion torque sequence is monotonically decreasing, outputting an adhesion unstable result; when the adhesion torque sequence is neither monotonically increasing nor decreasing, and presents a convex function feature, outputting an adhesion critical stable result; The boundary module calculates a dynamic allowable boundary of braking torque based on the adhesion limit, obtains a dynamic allowable boundary value, and the dynamic allowable boundary value The following is calculated: wherein is the dynamic admissible limit of braking torque, is the critical adhesion torque, is the dynamic admissible difference of torque, is the adjustment coefficient; a control module for taking the dynamic allowable boundary value as an amplitude limiting, limiting the output of the total braking force, and realizing dynamic allowable boundary control of the regenerative braking torque.

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