Regenerative torque control method and apparatus

Abstract

The invention relates to a control method of regenerative torque control equipment. The method comprises the steps that it is judged that a vehicle is in an unsteady state; based on the current working condition of the vehicle and a braking request of a driver, the corresponding working mode of the regenerative torque control equipment is determined; and in the corresponding working mode, the sliding regenerative torque, the braking regenerative torque and the hydraulic torque are distributed in real time. The invention further relates to regenerative torque control equipment, a computer readable storage medium, a brake control system and a vehicle.

Description

Technical Field

[0001] The present application relates to the field of regenerative torque control of vehicles, and more particularly, to a regenerative torque control device, a control method thereof, a computer-readable storage medium, a braking control system, and a vehicle. Background Art

[0002] For electric vehicles and hybrid vehicles with coasting regeneration ability and braking regeneration ability, the braking torque of a single wheel consists of coasting regenerative torque (or coasting recovery torque), braking regenerative torque (or braking recovery torque), and hydraulic torque.

[0003] In existing solutions, the above braking process involves three functional modules or systems: CRBS (Collaborative Regenerative Braking System), DTC (i.e., Drag Torque Control, also known as coasting energy recovery control), and ABS (i.e., Anti-Block System). However, existing regenerative torque control solutions cannot well coordinate functional modules or systems such as CRBS, DTC, and ABS, resulting in problems such as deceleration loss, low recovery efficiency, and electro-hydraulic coordination conflicts. Summary of the Invention

[0004] The inventors of the present application have realized that the reasons for deceleration loss and electro-hydraulic coordination conflict are as follows: (1) During the torque exit and hydraulic compensation process of CRBS, due to a large wheel-end slip ratio, the anti-lock braking system ABS is often triggered on one or more wheels, and the anti-lock braking system ABS issues a request to reduce hydraulic pressure. Since the ABS pressure reduction has a higher priority, when the CRBS fluid replenishment request conflicts with the ABS pressure reduction request, there is no hydraulic compensation during torque exit, resulting in deceleration loss; (2) During the CRBS exit process, DTC is also triggered simultaneously. Since DTC has a higher response priority, the torque interface of the VCU switches from CRBS to DTC, the torque interface jumps, and DTC instantaneously retracts torque, resulting in deceleration loss; in addition, DTC and CRBS are independent modules and are not synchronized, and there is no hydraulic compensation for the torque in the torque increase part of DTC (the actual fluid replenishment follows the CRBS request for fluid replenishment), resulting in unbalanced braking force.

[0005] In addition, the inventors of the present application have also realized that the reason for low recovery efficiency is that: since CRBS is an open-loop system, it cannot output appropriate torque according to the actual state of the vehicle. When the vehicle has an unstable trend, CRBS cannot judge the slight single-wheel skidding, disturbance on the road surface, or the severity of wheel locking, or vehicle instability based on the stability factor, but can only ensure that the wheels do not lock under the most demanding working conditions and retract the torque at the fastest slope. In this way, energy recovery may frequently exit, resulting in low recovery efficiency.

[0006] In view of the problems existing in the prior art, according to one aspect of the present application, a control method for a regenerative torque control device (i.e., RTC) is provided. The method includes: determining that the vehicle is in a non-steady state; determining a corresponding working mode of the regenerative torque control device based on the current working condition of the vehicle and the driver's braking request; and in the corresponding working mode, performing real-time distribution of the coasting regenerative torque, the braking regenerative torque, and the hydraulic torque.

[0007] As a supplement or replacement to the above solution, in the above method, determining that the vehicle is in a non-steady state includes: determining that the vehicle is in a non-steady state based on signals related to the vehicle dynamic state and the drive wheel state signals.

[0008] As a supplement or replacement to the above solution, in the above method, determining a corresponding working mode of the regenerative torque control device based on the current working condition of the vehicle and the driver's braking request includes: when the vehicle is in a coasting state or the driver's target braking deceleration is less than a first threshold, and the braking request is within the motor energy range, determining that the regenerative torque control device operates in a first mode, where in the first mode, the regenerative torque control device performs pure torque control, that is, the coasting regenerative torque and the braking regenerative torque are distributed according to the braking request, and the hydraulic torque is 0.

[0009] As a supplement or replacement to the above solution, in the above method, determining a corresponding working mode of the regenerative torque control device based on the current working condition of the vehicle and the driver's braking request further includes: when the driver's target braking deceleration is less than a second threshold, the second threshold is greater than the first threshold, and the allocated braking regenerative torque is dominant, determining that the regenerative torque control device operates in a second mode, where in the second mode, the regenerative torque control device performs electro-hydraulic co-control on the braking regenerative torque, that is, at least a part of the braking regenerative torque is compensated by the hydraulic torque.

[0010] As a supplement or replacement to the above solution, in the above method, determining a corresponding working mode of the regenerative torque control device based on the current working condition of the vehicle and the driver's braking request further includes: when the vehicle is in a coasting state or the driver's target braking deceleration is less than the first threshold, the coasting energy recovery is greater than a third threshold and the vehicle speed is less than a fourth threshold, or when the regenerative torque control device operating in the second mode still cannot ensure vehicle stability, determining that the regenerative torque control device operates in a third mode, where in the third mode, the regenerative torque control device performs full-torque electro-hydraulic co-control, that is, at least a part of the braking regenerative torque and at least a part of the coasting regenerative torque are both compensated by the hydraulic torque.

[0011] As a supplement or replacement of the above solution, in the above method, determining the corresponding working mode of the regenerative torque control device based on the current working condition of the vehicle and the driver's braking request further includes: on the basis that the regenerative torque control device works in the second mode or the third mode, if the hydraulic torque dominates the control during the process of increasing the vehicle torque by the regenerative torque control device according to the actual wheel-end slip ratio, it is determined that the regenerative torque control device works in the fourth mode, where in the fourth mode, the regenerative torque control device performs pure hydraulic control, that is, the coasting regenerative torque and the braking regenerative torque are 0 or a fixed value (this fixed value is, for example, a fixed torque value based on the longitudinal acceleration), and the hydraulic torque is controlled by the anti-lock braking system (ABS).

[0012] According to another aspect of the present application, there is provided a regenerative torque control device, characterized in that the device includes: a determination device for determining that the vehicle is in an unsteady state; a determination device for determining the corresponding working mode of the regenerative torque control device based on the current working condition of the vehicle and the driver's braking request; and a distribution device for, in the corresponding working mode, performing real-time distribution of the coasting regenerative torque, the braking regenerative torque, and the hydraulic torque.

[0013] As a supplement or replacement of the above solution, in the above device, the determination device is configured to: determine that the vehicle is in an unsteady state based on a signal related to the vehicle dynamic state and a drive wheel state signal.

[0014] As a supplement or replacement of the above solution, in the above device, the determination device is configured to: when the vehicle is in a coasting state or the driver's target braking deceleration is less than a first threshold, and the braking request is within the motor energy range, determine that the regenerative torque control device works in the first mode, where in the first mode, the regenerative torque control device performs pure torque control, that is, distributes the coasting regenerative torque and the braking regenerative torque according to the braking request, and the hydraulic torque is 0.

[0015] As a supplement or replacement of the above solution, in the above device, the determination device is further configured to: when the driver's target braking deceleration is less than a second threshold, the second threshold is greater than the first threshold, and the allocated braking regenerative torque dominates, determine that the regenerative torque control device works in the second mode, where in the second mode, the regenerative torque control device performs electro-hydraulic coordinated control on the braking regenerative torque, that is, at least a part of the braking regenerative torque is compensated by the hydraulic torque.

[0016] As a supplement or replacement of the above solution, in the above device, the determining device is further configured to: when the vehicle is in a coasting state or the target braking deceleration of the driver is less than the first threshold, the coasting energy recovery is greater than the third threshold and the vehicle speed is less than the fourth threshold, or when the regenerative torque control device still cannot ensure vehicle stability when operating in the second mode, determine that the regenerative torque control device operates in the third mode, wherein in the third mode, the regenerative torque control device performs full-torque electro-hydraulic collaborative control, that is, at least a part of the braking regenerative torque and at least a part of the coasting regenerative torque are compensated by the hydraulic torque.

[0017] As a supplement or replacement of the above solution, in the above device, the determining device is further configured to: on the basis that the regenerative torque control device operates in the second mode or the third mode, when the hydraulic torque dominates the control during the process of the regenerative torque control device increasing the vehicle torque according to the actual wheel-end slip ratio, determine that the regenerative torque control device operates in the fourth mode, wherein in the fourth mode, the regenerative torque control device performs pure hydraulic control, that is, the coasting regenerative torque and the braking regenerative torque are 0 or a fixed value, and the hydraulic torque is controlled by the anti-lock braking system (ABS).

[0018] According to another aspect of the present application, there is provided a computer-readable storage medium, the medium includes instructions, and the instructions execute the method as described above when running.

[0019] According to another aspect of the present application, there is provided a braking control system, the system includes: the regenerative torque control device as described above; and a vehicle control unit (VCU), wherein the regenerative torque control device provides the allocated coasting regenerative torque and braking regenerative torque to the vehicle control unit VCU for torque control.

[0020] According to another aspect of the present application, there is provided a vehicle, the vehicle includes the braking control system as described above.

[0021] When the control scheme of the regenerative torque control device in the embodiment of the present application determines that the vehicle is in a non-steady state, based on the current working condition of the vehicle and the driver's braking request, it determines the corresponding working mode of the regenerative torque control device, and allocates the coasting regenerative torque, the braking regenerative torque and the hydraulic torque in real time. In this way, the regenerative torque control device can adjust the torque increase in real time (continuous negative torque control), so that the vehicle always maintains the best adhesion and the best recovery efficiency; at the same time, according to the corresponding working mode of the regenerative torque control device, it is selected whether to perform hydraulic compensation, or how much torque to perform hydraulic compensation; while the hydraulic pressure follows the RTC torque for compensation, the balance of the total braking force can be ensured, and the driver's expectation for deceleration can be met. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other objects and advantages of the present application will become more fully apparent from the following detailed description taken in conjunction with the accompanying drawings, in which like or similar elements are denoted by like reference numerals.

[0023] Figure 1 FIG. shows a schematic flow chart of a control method of a regenerative torque control device according to an embodiment of the present application;

[0024] Figure 2 FIG. shows a schematic structural diagram of a regenerative torque control device according to an embodiment of the present application;

[0025] Figure 3 FIG. shows a schematic structural diagram of a braking control system according to an embodiment of the present application ； and

[0026] Figure 4 FIG. shows a schematic diagram of a control scheme of a regenerative torque control device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Hereinafter, a control scheme of a regenerative torque control device according to various exemplary embodiments of the present application will be described in detail with reference to the drawings.

[0028] Figure 1 FIG. shows a schematic flow chart of a control method 1000 of a regenerative torque control device according to an embodiment of the present application. As Figure 1 shown, the control method 1000 includes:

[0029] In step S110, it is determined that the vehicle is in a non-steady state;

[0030] In step S120, based on the current working condition of the vehicle and the driver's braking request, the corresponding working mode of the regenerative torque control device is determined; and

[0031] In step S130, under the corresponding working mode, the coasting regenerative torque, the braking regenerative torque, and the hydraulic torque are allocated in real time.

[0032] In the context of the present application, regenerative braking, also known as feedback braking, is a braking technology used in electric vehicles. During braking, the kinetic energy of the vehicle is converted and stored instead of being turned into useless heat. In the braking condition, the electric motor is switched to operate as a generator, and the inertia of the vehicle is used to drive the rotor of the electric motor to rotate, generating a reverse torque. A part of the kinetic energy or potential energy is converted into electrical energy and stored or utilized. Therefore, this is a regenerative process. In one embodiment, the regenerative torque may include coasting regenerative torque (Coastregen, also known as "coasting recovery torque") and braking regenerative torque (Brake regen, also known as "braking recovery torque").

[0033] In the context of the present application, the term "regenerative torque control device", as the name implies, refers to a device that controls the regenerative torque. In one embodiment, the regenerative torque control device is configured to receive various signals, including but not limited to, longitudinal deceleration ax, lateral deceleration ay, vehicle body yaw rate vGi, steering wheel angle SAS, four wheel speed signals WSS, wheel cylinder pressure signal, pedal travel signal, maximum capacity signal of the motor, target coasting torque and braking energy recovery torque, as well as vehicle state monitoring. Based on the received signals, the regenerative torque control device performs closed-loop control to perform continuous negative torque control, so that the vehicle always maintains the best adhesion and the best recovery efficiency. In addition, the regenerative torque control device also selects whether to perform hydraulic compensation or how much torque to perform hydraulic compensation according to the stable state of the vehicle. In this way, while the hydraulic pressure follows the RTC regenerative torque for compensation, the balance of the total braking force is ensured.

[0034] In the context of the present application, the term "non-steady state" refers to including the wheels generating slip and activating the ABS system; or the vehicle generating an unstable tendency, such as the phenomena of understeering and oversteering; or the road surface adhesion coefficients on both sides being non-uniform and the braking force cannot be effectively utilized; or the road surface adhesion coefficient jumping, and the wheels quickly locking or quickly recovering.

[0035] In one embodiment, the "closed-loop control" of the regenerative torque control device includes: the regenerative torque control device performs PID control according to the deviation between the wheel speed / axle speed and the reference vehicle speed, the deviation between the reference driver target braking deceleration and the actual vehicle deceleration. Moreover, the regenerative torque control device can set the target deviation based on the road surface adhesion coefficient and the wheel state, and adjust the real-time increase in torque size to always maintain the best adhesion and the best recovery efficiency. In one embodiment, the regenerative torque control device is configured to: in the non-steady state, if the ABS is triggered, the pressure of a single wheel is also reduced, but by adjusting the target torque and pressure, the non-sliding wheels can effectively obtain hydraulic compensation to achieve the best braking force. That is to say, the braking torque applied to each wheel can be determined individually.

[0036] Different from the prior art where DTC separately controls the coasting regenerative torque, CRBS separately controls the braking regenerative torque, and ABS separately controls the hydraulic torque, in the embodiments of the present application, the regenerative torque control device performs real-time allocation of the coasting regenerative torque, the braking regenerative torque, and the hydraulic torque based on closed-loop control according to the corresponding working mode, that is, different types of braking torques are aggregated into new control boundaries, rather than being limited to a single DTC / CRBS / ABS control boundary.

[0037] In step S110, it can be determined that the vehicle is in an unsteady state based on signals related to the vehicle dynamic state and the drive wheel state signals. In one embodiment, the signals related to the vehicle dynamic state can be obtained from the vehicle driving dynamic control system VDC. That is to say, it can be determined whether the vehicle is stable by obtaining the relevant signals representing the vehicle dynamic situation output by the VDC. In one embodiment, the drive wheel state signals may include signals such as longitudinal acceleration ax, lateral acceleration ay, yaw rate, steering wheel angle, and slip ratio. In other words, it can be determined whether the vehicle is stable by signals such as longitudinal acceleration ax, lateral acceleration ay, yaw rate, steering wheel angle, and slip ratio. In one embodiment, it can be determined that the vehicle is in an unsteady state (as described in step S110) based on both the signals related to the vehicle dynamic state and the drive wheel state signals, and then the subsequent regenerative torque control steps (such as steps S120, S130) are activated.

[0038] In step S120, based on the current working condition of the vehicle and the driver's braking request, the corresponding working mode of the regenerative torque control device is determined. In one embodiment, step S120 includes: when the vehicle is in the coasting state or the driver's target braking deceleration is less than the first threshold, and the braking request is within the motor energy range, it is determined that the regenerative torque control device operates in the first mode, where in the first mode, the regenerative torque control device performs pure torque control, that is, the coasting regenerative torque and the braking regenerative torque are allocated according to the braking request, and the hydraulic torque is 0. For example, pure torque control is performed on the drive shaft / wheel within the driver's target working condition when the following conditions are met: coasting or light braking request, non-emergency working condition, low adhesion coefficient (such as the adhesion coefficient is lower than 0.3), or bumpy disturbance working condition and the braking request is within the motor energy range. In this first mode, the regenerative torque control device performs pure energy recovery control (also known as "pure (regenerative) torque control"), the RTC torque increase part includes the coasting regenerative torque and the braking regenerative torque, and real-time splitting of the remaining torque into the coasting and braking regenerative torques is performed to achieve efficient energy recovery.

[0039] In one embodiment, step S120 further includes: when the target braking deceleration of the driver is less than a second threshold, the second threshold is greater than the first threshold, and the allocated braking regeneration torque is dominant (for example, the proportion of the braking regeneration torque is more than 80%), it is determined that the regeneration torque control device operates in a second mode, wherein in the second mode, the regeneration torque control device performs electro-hydraulic collaborative control on the braking regeneration torque, that is, at least a part of the braking regeneration torque is compensated by the hydraulic torque. For example, when the following conditions are met, electro-hydraulic collaborative control is performed on the braking regeneration torque (or braking energy recovery torque): light braking request, large braking energy recovery, non-emergency working condition, and low adhesion coefficient, or bump disturbance working condition. In this second mode, on the basis of the first mode, priority hydraulic compensation is performed on the torque of the braking energy recovery part. This is beneficial to realizing the gradual reduction of the braking torque and the electro-hydraulic collaboration during the exit process, and avoiding the loss of deceleration.

[0040] In one embodiment, step S120 further includes: when the vehicle is in a coasting state or the target braking deceleration of the driver is less than the first threshold, the coasting energy recovery is greater than a third threshold and the vehicle speed is less than a fourth threshold, or when the regeneration torque control device operates in the second mode and still cannot ensure the vehicle stability, it is determined that the regeneration torque control device operates in a third mode, wherein in the third mode, the regeneration torque control device performs full-torque electro-hydraulic collaborative control, that is, at least a part of the braking regeneration torque and at least a part of the coasting regeneration torque are both compensated by the hydraulic torque. For example, when the following conditions are met, full-torque electro-hydraulic collaborative control is performed: coasting or light braking request, coasting energy recovery greater than 0.1g, vehicle speed lower than 2m / s, or the motor capacity is limited due to temperature influence, or on the basis of the second mode, the hydraulic compensation of the braking energy recovery still cannot ensure the vehicle stability, including but not limited to the following situations:

[0041] (1) When there is a high-low jump, the slip ratio is greater than 10%, and the vehicle is prone to instability;

[0042] (2) The wheels tend to lock, or the wheel speed is lower than 2m / s, and the motor has no capacity and is prone to reverse rotation;

[0043] (3) In a cornering condition, there is a steering wheel input, and the wheel speed difference between the two sides is greater than 1m / s, and the vehicle is prone to instability;

[0044] (4) On a split road, when the single-wheel slip ratio is greater than 1m / s, deceleration loss is likely to occur;

[0045] (5) In a cornering condition of the vehicle, understeer or oversteer occurs, resulting in the triggering of the safety function of the ESP.

[0046] In this third mode, based on the second mode, during the RTC triggering process, hydraulic compensation for coasting energy recovery is added, that is, hydraulic compensation is performed on all energy recovery torques to achieve the optimal braking force and avoid vehicle instability and deceleration loss.

[0047] In one embodiment, step S120 further includes: based on the regenerative torque control device operating in the second mode or the third mode, during the process of the regenerative torque control device increasing the vehicle torque according to the actual wheel-end slip ratio, if the hydraulic torque dominates the control (for example, the hydraulic torque ratio is more than 80%), it is determined that the regenerative torque control device operates in the fourth mode, where in the fourth mode, the regenerative torque control device performs pure hydraulic control, that is, the coasting regenerative torque and the braking regenerative torque are 0 or a fixed value (this fixed value is, for example, a fixed torque value based on the longitudinal acceleration), and the hydraulic torque is controlled by the anti-lock braking system ABS. In this fourth mode, RTC keeps the target torque at 0, or a fixed torque value based on ax, and mainly distributes all braking forces through hydraulic pressure. The hydraulic pressure is controlled by the anti-lock braking system ABS. For example, when ABS is triggered, the hydraulic braking force is affected by the slip ratio, and the ABS performs pressure increasing and decreasing control.

[0048] In step S130, during the corresponding working mode, the coasting regenerative torque, the braking regenerative torque, and the hydraulic torque are distributed in real time. For example, according to the driver's input, for light braking, energy recovery is the main; for heavy braking, hydraulic pressure is the main. Specifically, during light braking, the brake pedal can be used to replace the accelerator single pedal to achieve different levels of energy recovery adjustment, efficiently integrate the implementation forms of braking forces at different pedal stroke depths, and achieve non-steady state stability control.

[0049] The control method 1000 of the regenerative torque control device in the foregoing various embodiments realizes continuous control of energy recovery under non-steady state conditions of the vehicle, and avoids frequent withdrawal of the recovery torque under slight disturbances.

[0050] Moreover, in one or more embodiments, the control method 1000 of the regenerative torque control device efficiently integrates coasting and braking energy recovery (equivalent to integrating the DTC and CRBS functions), uniformly distributes, coordinates, and splits the non-steady state electrical energy, and during the implementation of the DTC / ABS braking process, the braking energy recovery torque does not retreat, thereby realizing energy recovery control in the full speed range.

[0051] Furthermore, in one or more embodiments, the control method 1000 of the regenerative torque control device achieves better stability while ensuring the consistency of deceleration. The control scheme obtains the maximum braking force according to the road surface adhesion coefficient, and there will be no insufficient braking. During the RTC torque increase process, the coasting and braking torque parts of the torque increase part are split, and hydraulic compensation can be selectively performed to ensure the consistency of the vehicle deceleration; it also avoids phenomena such as one-sided wheel slipping and insufficient braking force on the other side wheel.

[0052] In addition, those skilled in the art can easily understand that the control method 1000 of the regenerative torque provided in the above one or more embodiments of the present application can be implemented by a computer program. For example, the computer program is included in a computer program product, and when the computer program is executed by a processor, it implements the control method 1000 of the regenerative torque control device in one or more embodiments of the present application. Another example is that when a computer-readable storage medium (such as a USB flash drive) storing the computer program is connected to a computer, running the computer program can execute the control method 1000 of the regenerative torque control device in one or more embodiments of the present application.

[0053] Reference Figure 2 , Figure 2 shows a schematic structural diagram of a regenerative torque control device 2000 according to an embodiment of the present application. The above regenerative torque control device 2000 includes: a determination device 210, a determination device 220, and a distribution device 230. Among them, the determination device 210 is used to determine that the vehicle is in a non-steady state; the determination device 220 is used to determine the corresponding working mode of the regenerative torque control device based on the current working condition of the vehicle and the driver's braking request; and the distribution device 230 is used to perform real-time distribution of the coasting regenerative torque, the braking regenerative torque, and the hydraulic torque in the corresponding working mode.

[0054] In one embodiment, the determination device 210 is configured to determine that the vehicle is in a non-steady state based on a signal related to the vehicle dynamic state and a drive wheel state signal. For example, the determination device 210 is configured to obtain a signal related to the vehicle dynamic state from the vehicle driving dynamic control system VDC. That is to say, the determination device 210 can determine whether the vehicle is stable by obtaining a relevant signal representing the vehicle dynamic situation output by the VDC. In one embodiment, the drive wheel state signal may include signals such as longitudinal acceleration ax, lateral acceleration ay, yaw rate, steering wheel angle, and slip ratio. In other words, the determination device 210 is configured to determine whether the vehicle is stable through signals such as longitudinal acceleration ax, lateral acceleration ay, yaw rate, steering wheel angle, and slip ratio.

[0055] In one embodiment, the determination device 220 is configured to: when the vehicle is in a coasting state or the driver's target braking deceleration is less than a first threshold, and the braking request is within the motor energy range, determine that the regenerative torque control device 2000 operates in a first mode, where in the first mode, the regenerative torque control device 2000 performs pure torque control, that is, distributes the coasting regenerative torque and the braking regenerative torque according to the braking request, and the hydraulic torque is 0. For example, when the following first condition is met, the determination device 220 is configured to determine that the regenerative torque control device 2000 operates in the first mode, that is, pure torque control is performed on the drive shaft / wheel within the driver's target operating conditions: coasting or light braking request, non-emergency condition, low adhesion coefficient (for example, the adhesion coefficient is less than 0.3), or bumpy disturbance condition and the braking request is within the motor energy range. In this first mode, the regenerative torque control device 2000 performs pure energy recovery control (also known as "pure (regenerative) torque control"), the RTC torque increase part includes the coasting regenerative torque and the braking regenerative torque, and the remaining torque is split into the coasting and braking regenerative torques in real time to achieve efficient energy recovery.

[0056] In another embodiment, the determination device 220 is further configured to: when the driver's target braking deceleration is less than a second threshold, the second threshold is greater than the first threshold, and the allocated braking regenerative torque is dominant, determine that the regenerative torque control device 2000 operates in a second mode, where in the second mode, the regenerative torque control device 2000 performs electro-hydraulic collaborative control on the braking regenerative torque, that is, at least a part of the braking regenerative torque is compensated by the hydraulic torque. For example, when the following second condition is met, the determination device 220 is configured to determine that the regenerative torque control device 2000 operates in the second mode, that is, electro-hydraulic collaborative control is performed on the braking regenerative torque (or braking energy recovery torque): light braking request, large braking energy recovery, non-emergency condition, and low adhesion coefficient, or bumpy disturbance condition. In this second mode, on the basis of the first mode, the regenerative torque control device 2000 preferentially compensates the torque of the braking energy recovery part with hydraulic pressure. This is beneficial to realizing the gradual reduction of the braking torque and the electro-hydraulic collaboration during the exit process, and avoiding the loss of deceleration.

[0057] In yet another embodiment, the determination device 220 is further configured to: when the vehicle is in a coasting state or the driver's target braking deceleration is less than the first threshold, the coasting energy recovery is greater than the third threshold and the vehicle speed is less than the fourth threshold, or when the regenerative torque control device 2000 still cannot ensure vehicle stability when operating in the second mode, determine that the regenerative torque control device 2000 operates in the third mode, wherein in the third mode, the regenerative torque control device 2000 performs full-torque electro-hydraulic collaborative control, that is, at least a part of the braking regenerative torque and at least a part of the coasting regenerative torque are compensated by the hydraulic torque. For example, when the following third condition is met, the determination device 220 is configured to determine that the regenerative torque control device 2000 operates in the second mode, that is, perform full-torque electro-hydraulic collaborative control: a coasting or light braking request, the coasting energy recovery is greater than 0.1g, the vehicle speed is lower than 2 m / s, or the motor capacity is limited due to temperature influence, or on the basis of the second mode, the hydraulic compensation of the braking energy recovery still cannot ensure vehicle stability, including but not limited to the following situations:

[0058] (1) When there is a high-low jump, the slip ratio is greater than 10%, and the vehicle is prone to instability;

[0059] (2) The wheel tends to lock up, or the wheel speed is lower than 2 m / s, and the motor has no capacity and is prone to reverse rotation;

[0060] (3) In a cornering condition, there is a steering wheel input, and the wheel speed difference between the two sides is greater than 1 m / s, and the vehicle is prone to instability;

[0061] (4) On a split road, when the single-wheel slip ratio is greater than 1 m / s, there is an easy loss of deceleration;

[0062] (5) When the vehicle is in a cornering condition, the vehicle experiences understeer or oversteer, resulting in the triggering of the safety function of the ESP.

[0063] In this third mode, on the basis of the second mode, during the RTC triggering process, the hydraulic compensation of the coasting energy recovery is increased, that is, hydraulic compensation is performed on all energy recovery torques to achieve the optimal braking force and avoid vehicle instability and deceleration loss.

[0064] In yet another embodiment, the determination device 220 is further configured to: based on the regenerative torque control device operating in the second mode or the third mode, determine that the regenerative torque control device 2000 is operating in the fourth mode during the process of the regenerative torque control device increasing the vehicle torque according to the actual wheel-end slip ratio. In the fourth mode, the regenerative torque control device 2000 performs pure hydraulic control, that is, the coasting regenerative torque and the braking regenerative torque are 0 or a fixed value, and the hydraulic torque is controlled by the anti-lock braking system (ABS). In this fourth mode, the regenerative torque control device 2000 maintains the target torque at 0, or a fixed torque value based on ax, and mainly performs all braking force distribution control hydraulically. The hydraulic pressure is controlled by the anti-lock braking system (ABS). For example, when the ABS is triggered, the hydraulic braking force is affected by the slip ratio, and the ABS performs pressure increase and decrease control.

[0065] The distribution device 230 is configured to perform real-time distribution of the coasting regenerative torque, the braking regenerative torque, and the hydraulic torque in the corresponding operating mode. For example, according to the driver's input, in the case of light braking, energy recovery is the main priority; in the case of heavy braking, hydraulics are the main priority. In this way, during light braking, through the distribution device 230, different levels of energy recovery can be adjusted on the basis of using the brake pedal instead of the accelerator single pedal, efficiently integrating the implementation forms of braking forces at different pedal stroke depths, and achieving non-steady state stability control.

[0066] The regenerative torque control device 2000 of the foregoing various embodiments realizes continuous control of energy recovery under non-steady state conditions of the vehicle, avoiding frequent withdrawal of the recovered torque under slight disturbances. Moreover, in one or more embodiments, the regenerative torque control device 2000 efficiently integrates coasting and braking energy recovery (equivalent to integrating the DTC and CRBS functions), uniformly distributes, coordinates, and splits the non-steady state electrical energy, and during the implementation of the DTC / ABS braking process, the braking energy recovery torque does not withdraw, thereby realizing energy recovery control over the entire speed range. Furthermore, in one or more embodiments, the regenerative torque control device 2000 achieves better stability while ensuring the consistency of deceleration. The regenerative torque control device 2000 can obtain the maximum braking force according to the road surface adhesion coefficient, and there will be no braking insufficiency. During the RTC torque increase process, the coasting and braking torque parts of the torque increase part are split, and hydraulic compensation can be selectively performed to ensure the consistency of the vehicle deceleration; it also avoids phenomena such as one-sided wheel skidding and insufficient braking force on the other side wheel.

[0067] In one embodiment, the above-mentioned regenerative torque control device 2000 can be integrated into the braking control system. In one embodiment, the braking control system may include: the above-mentioned regenerative torque control device and a vehicle control unit VCU. Among them, the regenerative torque control device provides the allocated coasting regenerative torque and braking regenerative torque to the vehicle control unit VCU for torque control.

[0068] Reference Figure 3 , which shows a schematic structural diagram of a braking control system according to an embodiment of the present application. As Figure 3 shown, 310 represents a driver braking request module (for example, determining the braking torque requested by the driver according to the stroke of the brake pedal), 320 represents a vehicle driving dynamic control system VDC module, 330 represents an anti-lock braking system ABS module, 340 represents a collaborative regenerative braking system CRBS module, 350 represents a hydraulic arbitration module, 360 represents a regenerative torque control device module, 370 represents a hydraulic control module, 380 represents a vehicle control unit VCU module, and 390 represents a brake execution module.

[0069] In Figure 3 , the regenerative torque control device module 360 receives signals related to the vehicle dynamic state (such as whether the vehicle is stable) from the vehicle driving dynamic control system VDC module 320; receives ABS-related output signals (such as whether ABS is activated) from the anti-lock braking system ABS module 330; receives signals related to braking regenerative torque (such as the current braking regenerative torque value) from the collaborative regenerative braking system CRBS module 340; receives an estimated value of the wheel cylinder pressure (which characterizes the magnitude of the current hydraulic braking torque of the wheel) from the hydraulic control module 370; and receives signals related to coasting regenerative torque (such as the current coasting regenerative torque value) from the vehicle control unit VCU module 380. Based on the input of these signals, the regenerative torque control device module 360 aggregates different types of braking torques into a new control boundary, thereby determining / calculating an appropriate braking torque (for example, the target regenerative torque T1), and providing it to the vehicle control unit VCU 380 for braking via the brake execution module 390 (such as including wheel brakes and motors, etc.).

[0070] In one or more embodiments, the foregoing braking control system can be integrated into a vehicle, which can include, for example, a pure electric vehicle, a hybrid vehicle, etc.

[0071] Figure 4 shows a schematic diagram of the control scheme of the regenerative torque control device according to an embodiment of the present application. As Figure 4As shown, the PID control unit 410 in the regenerative torque control device receives signals such as the coasting torque target 402 (determined according to, for example, the one-pedal or economy mode), the brake pedal input 404, and the maximum motor regeneration capacity 406. When it is determined that the vehicle is in an unstable state, as shown at 420, relevant information is provided to the PID control unit 410, and then it is further determined whether the first condition 430 is satisfied; if satisfied, the regenerative torque control device operates in the first mode - the pure torque control mode 435, and performs pure torque control on the sum of the coasting torque and the braking torque. Additionally, when it is determined that the vehicle is in an unstable state 420, it is also determined whether the second condition 440 is satisfied; if satisfied, the regenerative torque control device operates in the second mode 445 - hydraulic compensation for brake energy recovery. Moreover, when it is determined that the vehicle is in an unstable state 420, it is also determined whether the third condition 460 is satisfied; if satisfied, the regenerative torque control device operates in the third mode 465 - hydraulic compensation for both coasting and brake energy recovery. Furthermore, when it is determined that the vehicle is in an unstable state 420, it is also determined whether the fourth condition 470 is satisfied; if satisfied, the regenerative torque control device operates in the fourth mode 475 - hydraulic ABS braking. During the operation of this fourth mode 475, it is controlled by the hydraulic arbitration module 450 (ABS).

[0072] In one embodiment, the priorities of the four conditions increase in sequence, that is, the priority of the first condition is the lowest, and the priority of the fourth condition is the highest. For example, if the first condition and the second condition are both satisfied, it can be determined that the regenerative torque control device operates in the second mode.

[0073] In summary, the control scheme of the regenerative torque control device in the embodiment of the present application, when determining that the vehicle is in a non-steady state, based on the current working condition of the vehicle and the driver's braking request, determines the corresponding working mode of the regenerative torque control device, and performs real-time allocation of the coasting regenerative torque, the braking regenerative torque, and the hydraulic torque. In this way, the regenerative torque control device can adjust the magnitude of the torque increase in real time (continuous negative torque control), so that the vehicle always maintains the best adhesion and the best recovery efficiency; at the same time, according to the corresponding working mode of the regenerative torque control device, it is selected whether to perform hydraulic compensation, or how much torque to perform hydraulic compensation; while the hydraulic pressure follows the RTC torque for compensation, the balance of the overall braking force can be ensured, meeting the driver's expectation for deceleration.

[0074] The above examples mainly illustrate the regenerative torque control scheme of the embodiments of the present application. Although only some of the embodiments of the present application have been described, those of ordinary skill in the art should understand that the present application can be implemented in many other forms without departing from its gist and scope. Therefore, the examples and embodiments shown are regarded as illustrative rather than restrictive, and the present application may cover various modifications and substitutions without departing from the spirit and scope of the present application as defined by the various claims.

Claims

1. A control method for a regenerative torque control device, characterized in that, the method includes: determining that the vehicle is in a non-steady state; determining a corresponding working mode of the regenerative torque control device based on the current working condition of the vehicle and the driver's braking request; and allocating the coasting regenerative torque, the braking regenerative torque, and the hydraulic torque in real time in the corresponding working mode.

2. The method according to claim 1, wherein, determining that the vehicle is in a non-steady state includes: determining that the vehicle is in a non-steady state based on a signal related to the vehicle dynamic state and a driving wheel state signal.

3. The method according to claim 1, wherein, determining a corresponding working mode of the regenerative torque control device based on the current working condition of the vehicle and the driver's braking request includes: when the vehicle is in a coasting state or the driver's target braking deceleration is less than a first threshold, and the braking request is within the motor energy range, determining that the regenerative torque control device operates in a first mode, wherein in the first mode, the regenerative torque control device performs pure torque control, that is, allocating the coasting regenerative torque and the braking regenerative torque according to the braking request, and the hydraulic torque is 0.

4. The method according to claim 3, wherein, determining a corresponding working mode of the regenerative torque control device based on the current working condition of the vehicle and the driver's braking request further includes: when the driver's target braking deceleration is less than a second threshold, the second threshold is greater than the first threshold, and the allocated braking regenerative torque is dominant, determining that the regenerative torque control device operates in a second mode, wherein in the second mode, the regenerative torque control device performs electro-hydraulic coordinated control on the braking regenerative torque, that is, at least a part of the braking regenerative torque is compensated by the hydraulic torque.

5. The method according to claim 4, wherein, determining a corresponding working mode of the regenerative torque control device based on the current working condition of the vehicle and the driver's braking request further includes: when the vehicle is in a coasting state or the driver's target braking deceleration is less than the first threshold, the coasting energy recovery is greater than a third threshold and the vehicle speed is less than a fourth threshold, or when the regenerative torque control device operates in the second mode and still cannot ensure vehicle stability, determining that the regenerative torque control device operates in a third mode, wherein in the third mode, the regenerative torque control device performs full-torque electro-hydraulic coordinated control, that is, at least a part of the braking regenerative torque and at least a part of the coasting regenerative torque are both compensated by the hydraulic torque.

6. The method according to claim 5, wherein, determining a corresponding working mode of the regenerative torque control device based on the current working condition of the vehicle and the driver's braking request further includes: Based on the regenerative torque control device operating in the second mode or the third mode, when the regenerative torque control device increases the vehicle torque according to the actual wheel-end slip ratio and the hydraulic torque dominates the control, it is determined that the regenerative torque control device operates in the fourth mode, where in the fourth mode, the regenerative torque control device performs pure hydraulic control, that is, the coasting regenerative torque and the braking regenerative torque are 0 or a fixed value, and the hydraulic torque is controlled by the anti-lock braking system (ABS).

7. A regenerative torque control device, characterized in that, the device comprises: a determination device for determining that the vehicle is in an unsteady state; a determination means for determining the corresponding operating mode of the regenerative torque control device based on the current operating condition of the vehicle and the driver's braking request; and a distribution device for, in the corresponding operating mode, performing real-time distribution of the coasting regenerative torque, the braking regenerative torque, and the hydraulic torque.

8. The device according to claim 7, wherein, the determination device is configured to: determine that the vehicle is in an unsteady state based on a signal related to the vehicle dynamic state and a drive wheel state signal.

9. The device according to claim 7, wherein, the determination means is configured to: when the vehicle is in a coasting state or the driver's target braking deceleration is less than a first threshold value and the braking request is within the motor energy range, determine that the regenerative torque control device operates in the first mode, where in the first mode, the regenerative torque control device performs pure torque control, that is, the coasting regenerative torque and the braking regenerative torque are distributed according to the braking request, and the hydraulic torque is 0.

10. The device according to claim 9, wherein, the determination means is further configured to: when the driver's target braking deceleration is less than a second threshold value, the second threshold value is greater than the first threshold value, and the allocated braking regenerative torque dominates, determine that the regenerative torque control device operates in the second mode, where in the second mode, the regenerative torque control device performs electro-hydraulic coordinated control on the braking regenerative torque, that is, at least a part of the braking regenerative torque is compensated by the hydraulic torque.

11. The device according to claim 10, wherein, the determination means is further configured to: when the vehicle is in a coasting state or the driver's target braking deceleration is less than the first threshold value, the coasting energy recovery is greater than a third threshold value and the vehicle speed is less than a fourth threshold value, or when the regenerative torque control device operating in the second mode still cannot ensure vehicle stability, determine that the regenerative torque control device operates in the third mode, where in the third mode, the regenerative torque control device performs full-torque electro-hydraulic coordinated control, that is, at least a part of the braking regenerative torque and at least a part of the coasting regenerative torque are both compensated by the hydraulic torque.

12. The device according to claim 11, wherein, the determination means is further configured to: Based on the regenerative torque control device operating in the second mode or the third mode, when the regenerative torque control device increases the vehicle torque according to the actual wheel-end slip ratio and the hydraulic torque dominates the control, it is determined that the regenerative torque control device operates in the fourth mode, where in the fourth mode, the regenerative torque control device performs pure hydraulic control, that is, the coasting regenerative torque and the braking regenerative torque are 0 or a fixed value, and the hydraulic torque is controlled by the anti-lock braking system (ABS).

13. A computer-readable storage medium, characterized in that, the medium includes instructions that, when executed, perform the method according to any one of claims 1 to 6.

14. A braking control system, characterized in that, the system includes: a regenerative torque control device according to any one of claims 7 to 12; and a vehicle control unit (VCU), wherein the regenerative torque control device provides the allocated coasting regenerative torque and braking regenerative torque to the vehicle control unit (VCU) for torque control.

15. A vehicle, characterized in that, the vehicle includes the braking control system according to claim 14.

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