Vehicle regenerative braking control method, device and system, vehicle and storage medium

Abstract

The invention relates to a vehicle regenerative braking control method, device and system, a vehicle and a storage medium. The vehicle regenerative braking control method comprises the following steps that in response to starting of an anti-lock braking system, a wheel speed signal of the vehicle is obtained; judging whether the vehicle vibrates or not based on the obtained wheel speed signal; under the condition that the vehicle does not generate vibration, the braking of the vehicle is kept in a common ABS hydraulic braking mode; in a case where vibration is generated in a vehicle, it is determined whether to execute electric regenerative braking based on a maximum recoverable torque currently executable by a motor and a target electric braking torque, and in a case where the maximum recoverable torque is greater than a predetermined value and the target electric braking torque is less than or equal to the maximum recoverable torque, the maximum recoverable torque is greater than a predetermined value and the target electric braking torque is greater than or equal to a predetermined value. Gradually converting braking of the vehicle into an electric regenerative braking mode; otherwise, the braking of the vehicle is kept in a common ABS hydraulic braking mode. According to the invention, vibration generated during low-load braking of the vehicle can be reduced or completely eliminated.

Description

Technical Field

[0001] The present application relates to a vehicle braking control method, in particular to a vehicle regenerative braking control method based on electric regenerative braking and wire-controlled hydraulic braking, which can reduce or even completely eliminate the vibration of a vehicle (in particular an electric vehicle) during low-attachment braking (such as low-attachment emergency ABS braking). The present application also relates to a corresponding vehicle regenerative braking control device, system, vehicle and storage medium. Background Art

[0002] Regenerative braking (or electric braking) is a feature of electric vehicles that can coordinate hydraulic braking and electric braking according to the driver's actual braking needs to improve the vehicle's battery efficiency. During electric braking, the motor in the vehicle that is usually used as an electric motor to drive the vehicle can be used as a generator to convert the vehicle's kinetic energy into electrical energy, thereby charging the vehicle's power battery and increasing the range.

[0003] On the other hand, the wire-controlled hydraulic brake is a decoupled braking system that determines the driver's braking request by receiving the depth signal of the driver's brake pedal, and then pushes the corresponding amount of brake fluid in the master cylinder into the wheel cylinder through the decoupled transmission mechanism to achieve braking of the entire vehicle.

[0004] At present, many electric vehicles are equipped with both electric regenerative braking systems and wire-controlled hydraulic braking systems. In addition, existing known vehicles are basically equipped with anti-lock braking systems (ABS), so that when the vehicle takes emergency braking in an emergency, the braking force of the friction brake of the vehicle can be automatically controlled to prevent the wheels from being locked and maintain appropriate adhesion between the wheels and the ground, thereby ensuring the safety of the vehicle.

[0005] The inventors of the present application have found that electric vehicles (including pure electric vehicles and hybrid vehicles) are prone to vibration during low-acceleration emergency ABS braking, which may be attributed to the ABS control frequency being substantially close to the natural frequency of the powertrain of the electric vehicle (compared to internal combustion engine vehicles, the powertrain of electric vehicles generally has lower inertia). This abnormal phenomenon may affect the stability of the electric vehicle during braking and result in a low NVH (noise, vibration and harshness) level.

[0006] Therefore, it is necessary to improve the existing known electric vehicle braking control method (especially the braking control method during low-acceleration emergency ABS braking) to at least partially reduce or even completely overcome the above-mentioned deficiencies or defects. Summary of the invention

[0007] In view of the above background, the purpose of the present application is to propose a vehicle regenerative braking control method, which can reduce or even completely eliminate the vibration of a vehicle (especially an electric vehicle) during low-load braking (especially low-load emergency ABS braking).

[0008] In addition, the purpose of the present application is to propose a vehicle regenerative braking control device, system, vehicle and storage medium corresponding to the vehicle regenerative braking control method.

[0009] To this end, according to one aspect of the present application, a vehicle regenerative braking control method is provided, wherein the vehicle includes a motor that is usually used as a motor and used as a generator during electric regenerative braking (and is usually equipped with an electric regenerative braking system, a wire-controlled hydraulic braking system, and an anti-lock braking system), and the vehicle regenerative braking control method includes the following steps:

[0010] acquiring wheel speed signals of the vehicle in response to activation of an anti-lock braking system known as ABS;

[0011] Based on the obtained wheel speed signal, determining whether the vehicle generates vibration;

[0012] In the absence of vibrations in the vehicle, the vehicle's braking is maintained as a subsequent braking process coordinated by the vehicle's wire-controlled hydraulic brake system, thereby entering a normal ABS hydraulic braking mode; or

[0013] In the case where the vehicle is vibrating, whether to perform electric regenerative braking is determined based on the maximum recoverable torque currently executable by the motor and the target electric braking torque, wherein:

[0014] When the maximum recoverable torque is greater than a predetermined value (or referred to as a lower threshold) and the target electric braking torque is less than or equal to the maximum recoverable torque, gradually converting the braking of the vehicle into a subsequent braking process in which the electric regenerative braking system of the vehicle is used in cooperation with the electric regenerative braking system instead of the wire-controlled hydraulic braking system, thereby entering an electric regenerative braking mode, so as to eliminate the vibration; or

[0015] When the maximum recoverable torque is less than or equal to the predetermined value or the target electric braking torque is greater than the maximum recoverable torque, the vehicle's braking is maintained as a subsequent braking process implemented in cooperation with the wire-controlled hydraulic braking system, thereby entering the normal ABS hydraulic braking mode.

[0016] According to a feasible implementation manner, the wheel speed signal may be collected by a wheel speed sensor installed on the vehicle, and the determination of whether the vehicle is vibrating may be performed based on the acceleration / deceleration and / or the change frequency of the wheel speed signal.

[0017] According to a feasible implementation manner, the predetermined value may be set to a braking torque that enables the vehicle to generate a deceleration of 0.3 g.

[0018] According to a feasible implementation manner, the maximum regenerative torque may be obtained based on the remaining power or chargeable power of a power battery that can be charged by the motor during the electric regenerative braking.

[0019] According to a feasible implementation manner, the target electric braking torque may be calculated based on a target slip ratio calibrated in an actual vehicle, and compared with the maximum recoverable torque.

[0020] According to a feasible implementation manner, the target electric braking torque may be modified in real time based on a difference between the target slip ratio and an actual slip ratio.

[0021] According to a feasible implementation, there is a transition phase in the process of entering the electric regenerative braking mode, during which the braking torque generated by the motor of the electric regenerative braking system can be gradually increased (for example, gradually increased to a target value), and the braking torque generated by the friction brake of the wire-controlled hydraulic braking system can be gradually reduced (for example, reduced to zero). That is, in the initial stage, the braking torque actually generated can be coordinated between the motor of the electric regenerative braking system and the friction brake of the wire-controlled hydraulic braking system.

[0022] According to a feasible implementation manner, in the transition phase, the braking torque generated by the motor of the electric regenerative braking system may increase linearly, and the braking torque generated by the friction brake of the wire-controlled hydraulic braking system may decrease linearly.

[0023] According to a feasible implementation mode, the vehicle may be provided with the motor only on its front axle or rear axle, and braking of only the axle where the motor is located is implemented according to the vehicle regenerative braking control method; or, the vehicle may be provided with the motor on both its front axle and rear axle, and braking of both the front axle and the rear axle is implemented according to the vehicle regenerative braking control method.

[0024] According to a feasible implementation manner, the vehicle regenerative braking control method may be implemented by means of a control logic or program pre-stored in a braking system of the vehicle.

[0025] According to a feasible implementation manner, the vehicle may be a pure electric vehicle or a hybrid electric vehicle.

[0026] It can be seen from the above description that the vehicle regenerative braking control method of the present application is based on a combined system of wire-controlled hydraulic braking and electric regenerative braking. For vehicles equipped with these two systems (especially electric vehicles), the vehicle's smoothness and stability during low-attachment braking can be improved. In particular, the present application is mainly aimed at improving the braking process or method of electric vehicles during low-attachment braking. It can overcome the deficiencies or defects in the above-mentioned prior art in a simple, reliable and low-cost manner without significantly changing the structure or control system of the existing electric vehicle (it mainly changes the control strategy or method of the electric vehicle during low-attachment braking), and can reduce or even completely eliminate the vibration of the electric vehicle during low-attachment braking (especially low-attachment emergency ABS braking) by timely converting the traditional wire-controlled hydraulic braking to electric regenerative braking.

[0027] According to another aspect of the present application, a vehicle regenerative braking control device is provided, wherein the vehicle includes an electric machine that is normally used as a motor and is used as a generator during electric regenerative braking, and the vehicle regenerative braking control device includes:

[0028] a vehicle wheel speed signal acquisition module configured to acquire a wheel speed signal of the vehicle in response to activation of an anti-lock braking system referred to as ABS;

[0029] a vibration determination module configured to determine whether the vehicle generates vibration based on the obtained wheel speed signal; and

[0030] The vehicle regenerative braking control module is configured to control the braking process of the vehicle in the following manner based on the vibration judgment result:

[0031] In the absence of vibrations in the vehicle, the vehicle's braking is maintained as a subsequent braking process coordinated by the vehicle's wire-controlled hydraulic brake system, thereby entering a normal ABS hydraulic braking mode; or

[0032] In the case where the vehicle is vibrating, whether to perform electric regenerative braking is determined based on the maximum recoverable torque currently executable by the motor and the target electric braking torque, wherein:

[0033] When the maximum recoverable torque is greater than a predetermined value and the target electric braking torque is less than or equal to the maximum recoverable torque, gradually converting the braking of the vehicle into a subsequent braking process in which the electric regenerative braking system of the vehicle is used in cooperation with the electric regenerative braking system instead of the wire-controlled hydraulic braking system, thereby entering the electric regenerative braking mode; or

[0034] When the maximum recoverable torque is less than or equal to the predetermined value or the target electric braking torque is greater than the maximum recoverable torque, the vehicle's braking is maintained as a subsequent braking process implemented in cooperation with the wire-controlled hydraulic braking system, thereby entering the normal ABS hydraulic braking mode.

[0035] According to a feasible implementation mode, the vehicle wheel speed signal acquisition module can be configured to collect the wheel speed signal through a wheel speed sensor installed on the vehicle, and the vibration judgment module can be configured to judge whether the vehicle generates vibration based on the acceleration and deceleration and / or change frequency of the wheel speed signal.

[0036] According to another aspect of the present application, a vehicle regenerative braking control system is provided, comprising:

[0037] a signal generating device configured to generate and output a signal related to a braking process of the vehicle;

[0038] The vehicle regenerative braking control device as described above receives an input signal from the signal generating device and issues a corresponding program instruction;

[0039] The execution device is configured to receive program instructions from the vehicle regenerative braking control device, execute a corresponding braking mode and thereby control the braking process of the vehicle.

[0040] According to another aspect of the present application, a vehicle is provided, comprising:

[0041] A vehicle regenerative braking control device as described above; or

[0042] The vehicle regenerative braking control system as previously described.

[0043] According to another aspect of the present application, a computer-readable storage medium is provided, on which program instructions are stored. When executed by a processor, the program instructions enable the processor to implement the vehicle regenerative braking control method as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The features, advantages and other aspects of the present application will be more clearly understood through the following more detailed description of the present application given with reference to the accompanying drawings and in combination with exemplary embodiments. In the accompanying drawings:

[0045] Figure 1 Schematically shows a general flow chart of a vehicle regenerative braking control method according to an exemplary embodiment of the present application;

[0046] Figure 2 schematically illustrates wheel speed characteristics when vehicle vibration may occur during low-attachment emergency ABS braking of a vehicle;

[0047] Figure 3 Schematically illustrates an example of typical wheel speed fluctuations when a vehicle applicable to the vehicle regenerative braking control method of the present application may generate vibrations during low-attachment emergency ABS braking;

[0048] Figure 4 An example of a low-attachment emergency ABS braking effect that uses the vehicle regenerative braking control method of the present application to eliminate possible vehicle vibrations is schematically shown;

[0049] Figure 5 A schematic diagram of coordination between electric regenerative braking and hydraulic braking according to a vehicle regenerative braking control method of the present application;

[0050] Figure 6 A braking schematic diagram of a single-motor vehicle using the vehicle regenerative braking control method of the application;

[0051] Figure 7 The braking principle diagram of a dual-motor vehicle using the vehicle regenerative braking control method of the application. DETAILED DESCRIPTION

[0052] The following describes in detail the specific embodiments of the present application with reference to the accompanying drawings. It should be understood that the embodiments and related descriptions given herein should be understood as exemplary and do not constitute limitations on the present application.

[0053] In addition, it should be noted that, for the sake of simplicity and in order to more conveniently understand the main improvements or key points of the present application, the specification of the present application and its drawings focus on describing or illustrating the contents related to the main design points or principles of the present application, while omitting or simplifying the contents of other parts. Regarding the basic principles, control processes and other details of these omitted parts, they belong to the known technology in the art or those skilled in the art can make appropriate selections based on the existing knowledge and specific applications in the art, and will not be repeated here or illustrated in detail. In other words, methods, techniques and structures well-known in the art are not described in detail to avoid unnecessary obscurity of the core or substantive content of the present application.

[0054] First of all, it should be pointed out that the present application is particularly applicable to electric vehicles equipped with electric regenerative braking systems, wire-controlled hydraulic braking systems and anti-lock braking systems (ABS), which include any type of pure electric or hybrid vehicles known in the art, and the electric vehicle includes an electric motor that is normally used as an electric motor and is used as a generator during electric regenerative braking.

[0055] For electric vehicles, since their transmission mechanism is simpler than that of traditional fuel vehicles, they no longer require complex transmission mechanisms such as flywheels, clutches and gearboxes. They only need to directly connect the vehicle's half-axles through a reducer to drive the vehicle. In this case, as mentioned above, for electric vehicles with simple transmission mechanisms, during vehicle braking, especially low-adhesion emergency ABS braking, due to the withdrawal of electric brakes and the low rotational inertia of the power transmission system of the electric vehicle, vehicle resonance is likely to occur, and the adhesion of the tires is weakened, thereby affecting the smoothness and stability of the braking of the entire vehicle.

[0056] However, unfortunately, in the currently known prior art, this problem has not been recognized or taken seriously, and no reports on technical solutions to specifically solve the above problem have been found.

[0057] It is after fully recognizing the above-mentioned problems or defects existing in existing electric vehicles, such as during low-traction emergency ABS braking, that the inventors of the present application have proposed a new technical solution, which can reliably and conveniently achieve its intended purpose without making significant changes to the structure or control system of the existing electric vehicle (it mainly changes the control strategy or method of the electric vehicle during low-traction braking), and effectively overcome the above-mentioned problems or defects in the prior art.

[0058] In short, the goal or starting point of the present application is to coordinate the use of the wire-controlled hydraulic brake system and the electric regenerative brake system when the vibration of the vehicle is identified (for example, by the wire-controlled hydraulic brake system) during ABS braking of the vehicle, so as to utilize electric braking instead of hydraulic braking when implementation is permitted, thereby improving the smoothness of vehicle braking (for example, eliminating vibration caused by the proximity of the ABS control frequency to the natural frequency of the powertrain of the electric vehicle) and improving the energy recovery efficiency of the entire vehicle.

[0059] More specifically, if Figure 1 As shown, according to an exemplary embodiment of the present application, the basic logic or general process of the vehicle regenerative braking control method of the present application is as follows:

[0060] First, in response to the activation of the anti-lock braking system, a wheel speed signal of the vehicle is acquired (step S1);

[0061] Then, based on the obtained wheel speed signal, it is determined (or recognized) whether the vehicle generates vibration (step S2);

[0062] Next, based on the vibration judgment result, the braking process of the vehicle is controlled in a corresponding manner (step S3), which includes the following steps: if the vibration judgment result is that the vehicle does not generate vibration (that is, the vibration judgment result is N), the braking of the vehicle is maintained as a subsequent braking process implemented by the wire-controlled hydraulic braking system, and thus enters the ordinary ABS hydraulic braking mode (that is, the control method or process after the anti-lock braking system is started in the traditional prior art is maintained unchanged, and the relevant content is known in the prior art and will not be repeated here), that is, enter step S30; or

[0063] If the vibration judgment result is that the vehicle generates vibration (i.e., the vibration judgment result is Y), it is determined whether to perform electric regenerative braking based on the maximum recoverable torque currently executable by the motor and the target electric braking torque (step S31), which specifically determines whether the use condition that the maximum recoverable torque is greater than a predetermined value and the target electric braking torque is less than or equal to the maximum recoverable torque is satisfied (step S32), wherein,

[0064] When the maximum recoverable torque is greater than a predetermined value and the target electric braking torque is less than or equal to the maximum recoverable torque (i.e., the use condition judgment result is Y), the braking of the vehicle is gradually converted into a subsequent braking process in which the electric regenerative braking system replaces the wire-controlled hydraulic braking system, wherein electric regeneration is started and hydraulic braking exit is coordinated (step S33), and thus the electric regenerative braking mode is entered (i.e., the traditional wire-controlled hydraulic braking is converted into electric regenerative braking), so as to eliminate the vibration, that is, enter step S34; or

[0065] When the maximum recoverable torque is less than or equal to the predetermined value or the target electric braking torque is greater than the maximum recoverable torque (i.e., the use condition judgment result is N), the vehicle's braking is maintained as a subsequent braking process implemented in cooperation with the wire-controlled hydraulic braking system, and thus enters the normal ABS hydraulic braking mode, that is, directly enters step S35.

[0066] Obviously, the overall technical solution or technical concept of the present application has not been reported in the prior art before the present application was proposed. In fact, contrary to the design idea or principle of the present application, in existing known vehicles, the electric regenerative braking system is usually automatically shut down when the ABS is activated. The possible reason is that if the electric regenerative braking continues to apply the braking force generated by the motor back-drag to the wheel end, even if the ABS reduces the braking force of the wheel cylinder to zero, the motor back-drag force is still applied to the wheel end, which causes the wheel speed to be unrecoverable and the wheel to lock, affecting the braking stability of the vehicle.

[0067] It should be noted that, in the step of obtaining the wheel speed signal of the vehicle as described above, the wheel speed signal can be obtained by direct measurement with the aid of a wheel speed sensor, etc., or can be obtained by calculation using relevant data generated during the vehicle's travel (such as vehicle speed, vehicle acceleration, wheel acceleration, etc.), but is not limited thereto. The following is an example of the method and process of obtaining the wheel speed signal in the present application with the aid of a non-limiting embodiment.

[0068] Usually, if Figure 2 As shown in FIG. 1 , when the vehicle vibrates, the wheel speed signal will change periodically with a certain amplitude. In this case, (for example, a wire-controlled hydraulic brake system) can determine whether the vehicle vibrates during braking based on the acceleration and deceleration and / or change frequency of the wheel speed signal. Figure 2 In the figure, Cv represents the vehicle speed curve, Cw represents the wheel speed curve, and Pw represents the wheel speed fluctuation period (the inverse of which is the frequency).

[0069] Therefore, according to an exemplary embodiment of the present application, the wheel speed signal can be collected by a wheel speed sensor installed on the vehicle (for example, to detect the wheel speed of a selected wheel), and the judgment of whether the vehicle is vibrating or not can be based on the acceleration and deceleration and / or change frequency of the wheel speed signal, but is not limited to this.

[0070] With the help of Figure 3 , Figure 4 It can be seen that the beneficial effects can be obtained by adopting the vehicle control method of the present application, wherein Figure 3 , Figure 4 In the figure, Cv represents the vehicle speed curve, Cw represents the wheel speed curve, Ca represents the acceleration curve, t represents time, a represents acceleration, and v represents speed.

[0071] Figure 3 An example of typical wheel speed fluctuation when a vehicle suitable for the vehicle regenerative braking control method of the present application may generate vibration during low-adhesion emergency ABS braking is schematically shown.

[0072] from Figure 3 It can be seen from the figure that when the vehicle vibrates, the wheel speed and wheel acceleration will fluctuate periodically with a certain amplitude. Based on the fluctuation of wheel speed and its acceleration, it can be identified whether the vehicle vibrates during braking.

[0073] In addition, combined Figure 3 It can be seen that when hydraulic braking is used to generate vibration, the wheel speed vibrates violently, causing the vehicle to also vibrate violently.

[0074] In contrast, Figure 4The schematic diagram shows an example of the low-adhesion emergency ABS braking effect of using the vehicle regenerative braking control method of the present application to eliminate possible vehicle vibration. In other words, the braking effect after using electric regenerative braking instead of hydraulic braking can be seen in Figure 4 .

[0075] from Figure 4 It can be seen that when the vehicle's braking is changed from hydraulic braking to electric regenerative braking, the wheel speed does not fluctuate, that is, the vehicle does not vibrate. According to the present application, after the brake-by-wire system recognizes that the vehicle is vibrating, the vehicle's braking mode is gradually changed from hydraulic braking mode to regenerative electric braking mode, and the wheel speed (especially, the wheel speed of the wheel on the shaft where the motor is located) is maintained at a certain slip rate through electric regenerative braking, thereby ensuring the smoothness and stability of the vehicle during braking.

[0076] Moreover, combined with Figure 4 It can be seen that the wheel speed does not jitter, that is, the vehicle does not jitter, and the wheels remain in a certain slip range, thereby improving the comfort of the vehicle during braking. At the same time, due to the use of electric regenerative braking mode, the energy recovery efficiency of the vehicle can be improved.

[0077] According to an exemplary embodiment of the present application, in the process of entering the electric regenerative braking mode, the control system of the vehicle will first verify (for example, by detecting the remaining power or rechargeable power of the power battery that can be charged by the motor during the electric regenerative braking) the maximum recoverable torque that the motor can currently perform (or generate). Generally, for example, if the maximum recoverable torque is not enough to cause the vehicle to generate a deceleration of 0.3g (i.e., 0.3 times the acceleration of gravity), the subsequent control logic for entering the electric regenerative braking mode will not be executed. This is because: as mentioned above, in most cases, the vibration when the vehicle according to the present application is braked occurs on a low-adhesion road surface, and the deceleration that can be generated by the low-adhesion road surface is generally within 0.3g. If the subsequent control logic for entering the electric regenerative braking mode is executed, the control system of the vehicle can, for example, calculate the target electric braking torque (or expected braking torque) based on the target slip rate of the wheel of the shaft where the motor is located (this target slip rate can be confirmed in the actual vehicle calibration, for example). Once the vibration of the vehicle is identified, the target electric braking torque will be assigned an initial value, which is determined by the actual vehicle calibration, and the target electric braking torque can be corrected in real time according to the difference between the target slip rate and the actual slip rate, and finally the current target electric braking torque is calculated. Subsequently, when the maximum recoverable torque currently executable by the motor is greater than the target electric braking torque, the actual braking torque will be executed by the motor at the wheel end, thereby achieving the required vehicle braking. In the process of entering the electric regenerative braking mode, the intervention of electric regenerative braking and the exit of hydraulic braking need to go through a transition stage. This transition stage needs to ensure the smoothness of vehicle braking, and the driver cannot obviously feel the loss of deceleration. In this transition stage, the slope of the intervention of electric regenerative braking and the slope of the exit of hydraulic braking can be set to the calibrated parameters and determined in the actual calibration process of each vehicle model. At the same time, since the technical solution of the present application is only for the decoupled braking system, it does not involve the problem of brake pedal feel during the conversion of hydraulic electric braking.

[0078] For example, in the transition phase, the braking torque (or braking force) of the motor may increase monotonically as the braking process proceeds, and the braking torque (or braking force) of the friction brake may decrease monotonically as the braking process proceeds. Preferably, in the initial stage of entering the electric regenerative braking mode, the braking torque of the motor and the braking torque of the friction brake both change linearly as the braking process proceeds.

[0079] More specifically, as an example, the determination and control manner of the electric braking torque in the present application is described below.

[0080] For example, when the wire control brake system recognizes that the vehicle is vibrating and the braking torque that the motor can achieve is sufficient to provide a deceleration of 0.3g for the entire vehicle (and the braking torque is greater than the target electric braking torque), the braking system can output the electric braking torque determined and preset by the software accordingly, and this braking torque is set to gradually increase at a certain slope, and the hydraulic braking force is set to gradually exit at a certain slope. The two slopes here are calibration quantities, which can be determined by actual vehicle calibration (that is, the motor's intervention slope and the hydraulic exit slope will be used as software calibration parameters, and the specific setting of the parameters can be determined during the actual vehicle calibration) to ensure the smoothness of the vehicle's deceleration during the hydraulic-electric braking conversion. The braking system can then perform closed-loop control based on the target slip rate preset by the software and the actual slip rate calculated based on the wheel speed measured by the wheel speed sensor to adjust and obtain the real-time electric braking torque, thereby controlling the deceleration of the vehicle during electric braking.

[0081] See also Figure 5 (Among them Figure 5 In the figure, Cv represents the vehicle speed curve, Cw represents the wheel speed curve, t represents time, v represents speed, T represents braking torque, C1 represents the hydraulic braking curve, and C2 represents the electric regenerative braking curve). In the process of entering the electric regenerative braking mode, the electric braking torque obtained in the above manner can be sent to the motor, so that the motor can generate braking force on the vehicle through electric braking. During this period, while the electric braking torque (or the braking force of the motor) gradually increases at a certain slope, the wire-controlled hydraulic braking system can coordinate its own hydraulic unit to exit the hydraulic braking at a certain slope, thereby ensuring a smooth transition from hydraulic braking to electric braking. The exit slope of this hydraulic braking force will be determined by the calibration of the whole vehicle, so that the deceleration of the whole vehicle is smooth and continuous when the hydraulic braking transitions to the electric braking. In addition, since the wire-controlled hydraulic braking system is a decoupled wire-controlled hydraulic braking system, that is, the driver's brake pedal and the push rod that actually pushes the brake fluid into the wheel cylinder are a decoupled system, the driver will not perceive the change in the feel of the brake pedal.

[0082] More specifically, if Figure 5 As shown in the left part of , when the vehicle vibrates after ABS braking, the wheel speed and wheel acceleration will fluctuate periodically with a certain amplitude, and the hydraulic brake torque will also fluctuate periodically with a certain amplitude.

[0083] In contrast, when the vehicle regenerative braking control method according to the present application is adopted, when the vehicle vibration is detected, the hydraulic brake can be gradually replaced by the electric regenerative brake ( Figure 5 The dotted line portion in FIG. 2 generates braking force on the vehicle.

[0084] from Figure 5It can be seen from the figure that during the process of entering the electric regenerative braking, there is a transition phase (which is in a very short time, for example, in seconds), in which the wire-controlled hydraulic brake system can coordinate its own hydraulic unit to exit the hydraulic braking at a certain slope (that is, gradually reduce to zero) while the electric braking torque gradually increases at a certain slope, thereby ensuring a smooth transition from hydraulic braking to electric braking. Afterwards, the electric braking torque can be maintained at a constant value for a certain period of time, and then gradually reduced to zero.

[0085] Without departing from the basic principles or spirit of the present application, the vehicle regenerative braking control method of the present application can be appropriately adjusted or changed in specific steps according to different vehicle models or application scenarios. Figure 6 , Figure 7 Some specific application examples of the vehicle regenerative braking control method of the present application are given.

[0086] 1. Vehicles with the motor installed on only one axle (front axle or rear axle):

[0087] like Figure 6 As shown, in the case where only one axis is provided with a motor, after obtaining the wheel speed signal of the vehicle in response to the activation of the anti-lock braking system (step S100, which can basically correspond to the step S1 described above), the vehicle vibration and whether to execute the electric regenerative braking mode are determined (step 200, which can basically correspond to the steps S2 and S32 described above). When it is determined that the vehicle does not vibrate or does not execute the electric regenerative braking mode (i.e., the judgment result is N), each axis of the vehicle maintains the ordinary ABS hydraulic braking mode (step 300); when it is determined that the vehicle vibrates and can execute the electric regenerative braking mode (i.e., the judgment result is Y), the wire-controlled hydraulic braking system requests the electric braking torque from the motor according to the motor capacity, and at this time, the braking of the axis where the motor is located (motor axis) can be implemented according to the method of the present application (i.e., relying on electric regenerative braking) (i.e., entering step S400, where the axis where the motor is located can enter the electric regenerative braking mode), while the braking of the axis where the motor is not located (non-motor axis) continues to be performed in a hydraulic braking manner (i.e., entering step S500, where the axis where the non-motor is located maintains the ordinary ABS hydraulic braking mode). The wire-controlled hydraulic brake system needs to open the outlet valve of the shaft where the motor is located so that there is no hydraulic pressure on the shaft, rather than the motor shaft for normal ABS control, that is, normally opening and closing the inlet valve and outlet valve of the shaft.

[0088] 2. Split-axle models with motors on both the front and rear axles:

[0089] Unlike models where the motor drives only one axle, split-axle models can provide braking force on both the front and rear axles. Figure 7As shown, after the wheel speed signal of the vehicle is obtained in response to the activation of the anti-lock braking system (step S100, which can basically correspond to the step S1 described above), the vehicle vibration and whether to execute the electric regenerative braking mode are determined (step 200, which can basically correspond to the steps S2 and S32 described above). When it is determined that the vehicle does not vibrate or does not execute the electric regenerative braking mode (i.e., the judgment result is N), each shaft of the vehicle maintains the ordinary ABS hydraulic braking mode (step 300); when it is determined that the vehicle vibrates and can execute the electric regenerative braking mode (i.e., the judgment result is Y), the wire-controlled hydraulic braking system will send a braking torque request to the two motors at the same time according to the capabilities of the front and rear axles. At this time, the braking of one motor shaft can be implemented according to the method of the present application (i.e., relying on electric regenerative braking) (i.e., entering step S400, where the motor shaft can enter the electric regenerative braking mode), and the other motor shaft can also be implemented according to the method of the present application (i.e., relying on electric regenerative braking) (i.e., entering step S600, where the other motor shaft can also enter the electric regenerative braking mode). In particular, for example, once the vehicle shakes, the regenerative energy of the front and rear motors will be used for braking, and the distribution of the electric regenerative energy braking force of the front and rear axles can be determined based on the proportional relationship between the front and rear axle brakes. At the same time, the hydraulic brake system needs to open the outlet valves of the front and rear axles to release the braking force of the wheel cylinders, and then the pressure-building push rod of the hydraulic brake system returns to the initial position. This process can determine the relevant parameters based on the vehicle calibration to ensure the smoothness and consistency of the deceleration of the vehicle when the vehicle is converted from hydraulic braking to electric regenerative braking.

[0090] As mentioned above, the vehicle applicable to the present application may be a pure electric vehicle or a hybrid electric vehicle.

[0091] The control method of the present application can be executed by means of the control device of the present application, and the various technical features or contents described for the control method are also applicable to the control device. The various steps and technical details of the control method described above can be stored in the control device in the form of software, or can also be implemented in the form of a combination of software and hardware.

[0092] The method of the present application can be implemented without substantially adding any hardware, and the required software or control logic can be integrated into the current braking system. In other words, the method of the present application can be implemented with the aid of control logic or a program pre-stored in the braking system (e.g., a control device or controller included therein). According to an exemplary embodiment of the present application, in accordance with the vehicle regenerative braking control method, a vehicle regenerative braking control device is also provided, wherein the vehicle includes a motor that is usually used as a motor and is used as a generator during electric regenerative braking, and the vehicle regenerative braking control device may include:

[0093] a vehicle wheel speed signal acquisition module, which may be configured to acquire a wheel speed signal of the vehicle in response to activation of an anti-lock braking system referred to as ABS;

[0094] a vibration determination module, which may be configured to determine whether the vehicle generates vibration based on the obtained wheel speed signal; and

[0095] The vehicle regenerative braking control module may be configured to control the braking process of the vehicle in the following manner based on the vibration determination result:

[0096] In the absence of vibrations in the vehicle, the vehicle's braking is maintained as a subsequent braking process coordinated by the vehicle's wire-controlled hydraulic brake system, thereby entering a normal ABS hydraulic braking mode; or

[0097] In the case where the vehicle is vibrating, whether to perform electric regenerative braking is determined based on the maximum recoverable torque currently executable by the motor and the target electric braking torque, wherein:

[0098] When the maximum recoverable torque is greater than a predetermined value and the target electric braking torque is less than or equal to the maximum recoverable torque, gradually converting the braking of the vehicle into a subsequent braking process in which the electric regenerative braking system of the vehicle is used in cooperation with the electric regenerative braking system instead of the wire-controlled hydraulic braking system, thereby entering the electric regenerative braking mode; or

[0099] When the maximum recoverable torque is less than or equal to the predetermined value or the target electric braking torque is greater than the maximum recoverable torque, the vehicle's braking is maintained as a subsequent braking process implemented in cooperation with the wire-controlled hydraulic braking system, thereby entering the normal ABS hydraulic braking mode.

[0100] According to an exemplary embodiment of the present application, the vehicle wheel speed signal acquisition module can be configured to collect the wheel speed signal through a wheel speed sensor installed on the vehicle, and the vibration judgment module can be configured to judge whether the vehicle generates vibration based on the acceleration and deceleration and / or change frequency of the wheel speed signal.

[0101] According to an exemplary embodiment of the present application, a vehicle regenerative braking control system is also provided, which may include:

[0102] A signal generating device (which may include, for example, a wheel speed sensor, etc.), which is configured to generate and output a signal related to a braking process of the vehicle;

[0103] The vehicle regenerative braking control device as described above receives an input signal from the signal generating device and issues a corresponding program instruction;

[0104] An execution device (which may, for example, include a friction brake, an electric motor that is usually used as an electric motor and is used as a generator during electric regenerative braking, etc.) is configured to receive program instructions from the vehicle regenerative braking control device, execute a corresponding braking mode and thereby control the vehicle's braking process.

[0105] According to an exemplary embodiment of the present application, a vehicle is also provided, which may include the vehicle regenerative braking control device as described above or the vehicle regenerative braking control system as described above.

[0106] According to an exemplary embodiment of the present application, a computer-readable storage medium is further provided, on which program instructions are stored. When executed by a processor, the program instructions can enable the processor to implement the vehicle regenerative braking control method according to the present application.

[0107] The present application has been described in detail above in conjunction with specific embodiments. Obviously, as mentioned above, the embodiments described above and shown in the accompanying drawings should be understood as exemplary and do not constitute a limitation to the present application. For those skilled in the art, various modifications or changes can be made to the present application without departing from the spirit of the present application. Obviously, these modifications or changes do not depart from the scope of the present application.

Claims

1. A vehicle regenerative braking control method, the vehicle including an electric machine that is normally used as a motor and is used as a generator during electric regenerative braking, the vehicle regenerative braking control method comprising the following steps: acquiring wheel speed signals of the vehicle in response to activation of an anti-lock braking system known as ABS; Based on the obtained wheel speed signal, determining whether the vehicle generates vibration; When the vehicle does not vibrate, the vehicle is braked in a subsequent braking process coordinated by the vehicle's wire-controlled hydraulic brake system, thereby entering a normal ABS hydraulic brake mode; or In the case where the vehicle is vibrating, whether to perform electric regenerative braking is determined based on the maximum recoverable torque currently executable by the motor and the target electric braking torque, wherein: When the maximum recoverable torque is greater than a predetermined value and the target electric braking torque is less than or equal to the maximum recoverable torque, gradually converting the braking of the vehicle into a subsequent braking process in which the electric regenerative braking system of the vehicle replaces the wire-controlled hydraulic braking system, thereby entering the electric regenerative braking mode; or When the maximum recoverable torque is less than or equal to the predetermined value or the target electric braking torque is greater than the maximum recoverable torque, the vehicle's braking is maintained as a subsequent braking process implemented in cooperation with the wire-controlled hydraulic braking system, thereby entering the normal ABS hydraulic braking mode.

2. The vehicle regenerative braking control method according to claim 1, wherein: The wheel speed signal is collected by a wheel speed sensor installed on the vehicle, and the determination of whether the vehicle is vibrating is performed based on the acceleration / deceleration and / or the change frequency of the wheel speed signal.

3. The vehicle regenerative braking control method according to claim 1, wherein: The predetermined value is set to a braking torque that enables the vehicle to generate a deceleration of 0.3 g.

4. The vehicle regenerative braking control method according to claim 1, wherein: The maximum recoverable torque is obtained based on a remaining amount of power or a chargeable amount of power battery that can be charged by the motor during the electric regenerative braking.

5. The vehicle regenerative braking control method according to claim 1, wherein: The target electric braking torque is calculated based on a target slip ratio calibrated in an actual vehicle, and is compared with the maximum recoverable torque.

6. The vehicle regenerative braking control method according to claim 5, wherein: The target electric braking torque is corrected in real time based on a difference between the target slip ratio and an actual slip ratio.

7. The vehicle regenerative braking control method according to claim 1, wherein: There is a transition phase in the process of entering the electric regenerative braking mode, during which the braking torque generated by the motor of the electric regenerative braking system gradually increases, and the braking torque generated by the friction brake of the wire-controlled hydraulic braking system gradually decreases.

8. The vehicle regenerative braking control method according to claim 7, wherein: In the transition phase, the braking torque generated by the motor of the electric regenerative braking system increases linearly, and the braking torque generated by the friction brake of the control-by-wire hydraulic braking system decreases linearly.

9. The vehicle regenerative braking control method according to any one of claims 1 to 8, wherein: The vehicle is provided with the motor only on its front axle or rear axle, and braking of only the axle where the motor is located is implemented according to the vehicle regenerative braking control method; or The electric vehicle is provided with the motors on both the front and rear axles, and the braking of the front and rear axles is implemented according to the vehicle regenerative braking control method.

10. The vehicle regenerative braking control method according to any one of claims 1 to 8, wherein: The vehicle regenerative braking control method is implemented by means of a control logic or program pre-stored in a regenerative braking control system of the vehicle; and / or The vehicle is a pure electric vehicle or a hybrid electric vehicle.

11. A vehicle regenerative braking control device, the vehicle including an electric machine that is normally used as a motor and is used as a generator during electric regenerative braking, the vehicle regenerative braking control device comprising: a vehicle wheel speed signal acquisition module configured to acquire a wheel speed signal of the vehicle in response to activation of an anti-lock braking system referred to as ABS; a vibration determination module configured to determine whether the vehicle generates vibration based on the obtained wheel speed signal; as well as The vehicle regenerative braking control module is configured to control the braking process of the vehicle in the following manner based on the vibration judgment result: When the vehicle does not vibrate, the vehicle is braked in a subsequent braking process coordinated by the vehicle's wire-controlled hydraulic brake system, thereby entering a normal ABS hydraulic brake mode; or In the case where the vehicle is vibrating, whether to perform electric regenerative braking is determined based on the maximum recoverable torque currently executable by the motor and the target electric braking torque, wherein: When the maximum recoverable torque is greater than a predetermined value and the target electric braking torque is less than or equal to the maximum recoverable torque, gradually converting the braking of the vehicle into a subsequent braking process in which the electric regenerative braking system of the vehicle replaces the wire-controlled hydraulic braking system, thereby entering the electric regenerative braking mode; or When the maximum recoverable torque is less than or equal to the predetermined value or the target electric braking torque is greater than the maximum recoverable torque, the vehicle's braking is maintained as a subsequent braking process implemented in cooperation with the wire-controlled hydraulic braking system, thereby entering the normal ABS hydraulic braking mode.

12. The vehicle regenerative braking control device according to claim 11, wherein: The vehicle wheel speed signal acquisition module is configured to collect the wheel speed signal through a wheel speed sensor installed on the vehicle, and the vibration judgment module is configured to judge whether the vehicle generates vibration based on the acceleration and deceleration and / or change frequency of the wheel speed signal.

13. A vehicle regenerative braking control system, comprising: a signal generating device configured to generate and output a signal related to a braking process of the vehicle; The vehicle regenerative braking control device according to claim 11 or 12, which receives an input signal from the signal generating device and issues a corresponding program instruction; The execution device is configured to receive program instructions from the vehicle regenerative braking control device, execute a corresponding braking mode and thereby control the braking process of the vehicle.

14. A vehicle comprising: The vehicle regenerative braking control device according to claim 11 or 12; or The vehicle regenerative braking control system according to claim 13. 15 . A computer-readable storage medium having program instructions stored thereon, which, when executed by a processor, causes the processor to implement the vehicle regenerative braking control method according to any one of claims 1 to 10.

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