Vehicle braking control method and device, power domain controller and vehicle

Abstract

The invention discloses a vehicle braking control method and device, a power domain controller and a vehicle, and relates to the field of vehicle control. The method comprises the steps that whether the execution condition of a downhill constant speed function is met or not is judged; if the execution condition is met, total braking force needed by the vehicle is determined; determining an electric braking force which can be provided by the vehicle at the current vehicle speed; controlling an electric brake to brake so as to provide electric braking force; and controlling the hydraulic retarder to brake so as to compensate the difference value between the total braking force and the electric braking force. The defect that the braking force of the electric brake is insufficient is made up through compensation of the hydraulic retarder besides the braking dominated by the electric brake. The braking force is distributed, so that the vehicle can run downhill at a heavy load according to a set vehicle speed, the economical efficiency of the whole vehicle is guaranteed, electricity feedback is utilized to the maximum extent, and the safety of the vehicle is also guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicle control, in particular to a vehicle braking control method and device, a power domain controller and a vehicle. BACKGROUND

[0002] New energy pure electric, hybrid, extended range vehicles generally have a coasting energy feedback function. This function is very important for vehicles under heavy load on long slopes, especially heavy trucks, which can reduce brake pad heating and improve vehicle safety factor. However, in some special working conditions, the vehicle load is large and the slope is large. The coasting energy feedback braking force provided by the electric brake alone is not enough to hold the vehicle, and the vehicle will continue to accelerate, which poses a safety hazard. SUMMARY

[0003] The purpose of the present application is to provide a vehicle braking control method, device, power domain controller and vehicle. In addition to the electric brake dominated braking, the hydraulic retarder is used to compensate for the deficiency of the electric brake braking force. The braking force is distributed so that the vehicle can be loaded down the slope at the set speed, which not only maximizes the use of electric feedback but also ensures the safety of the vehicle.

[0004] To solve the above technical problems, the present application provides a vehicle braking control method, comprising:

[0005] determining whether the execution condition of the downhill speed limiting function is met;

[0006] if the execution condition is met, determining the total braking force required by the vehicle;

[0007] determining the electric braking force that can be provided by the vehicle at the current vehicle speed;

[0008] controlling the electric brake to provide the electric braking force;

[0009] controlling the hydraulic retarder to compensate for the difference between the total braking force and the electric braking force.

[0010] On the other hand, determining whether the execution condition of the downhill speed limiting function is met, comprising:

[0011] determining whether the speed of the vehicle is greater than the set speed, the accelerator and brake of the vehicle are stepped down, the speed limiting switch is pressed down, and the slope of the road where the vehicle is located is less than the set slope;

[0012] if the speed is greater than the set speed, the accelerator and the brake are not stepped down, the speed limiting switch is pressed down, and the slope is less than the set slope, it is determined that the execution condition of the downhill speed limiting function is met.

[0013] On the other hand, determining the total braking force required by the vehicle, comprising:

[0014] Determine the target speed of the vehicle;

[0015] Determine the real-time speed of the vehicle;

[0016] The total braking force required by the vehicle is determined based on the speed difference between the real-time vehicle speed and the target vehicle speed.

[0017] On the other hand, determining the total braking force required by the vehicle based on the speed difference between the real-time vehicle speed and the target vehicle speed includes:

[0018] Determine the speed difference between the real-time vehicle speed and the target vehicle speed;

[0019] The total braking force required by the vehicle is determined according to the braking force calculation formula, which is u(k)=Kp×Δv(k)+Ki×Ts×ΣΔv(i);

[0020] Where u(k) is the total braking force at time k, Kp is the proportional coefficient, Δv(k) is the speed difference at time k, Ki is the integral coefficient, Ts is the sampling period, and ΣΔv(i) is the cumulative sum of vehicle speed deviations from the initial time to time k.

[0021] On the other hand, determining the electric braking force that the vehicle can provide at the current speed includes:

[0022] At the current vehicle speed, the available electric braking force is determined based on the upper limit of the vehicle's power battery feedback capacity and the upper limit of the vehicle's drive system feedback capacity.

[0023] On the other hand, before controlling the hydraulic retarder to compensate for the difference between the total braking force and the electric braking force, the method further includes:

[0024] Determine whether the electric braking force is less than the total braking force;

[0025] If the electric braking force is less than the total braking force, then the process proceeds to control the hydraulic retarder to compensate for the difference between the total braking force and the electric braking force.

[0026] On the other hand, after determining whether the electric braking force is less than the total braking force, the method further includes:

[0027] If the electric braking force is greater than or equal to the total braking force, then the braking force is provided solely by the electric brake.

[0028] To solve the above-mentioned technical problems, the present invention also provides a vehicle braking control device, comprising:

[0029] Memory, used to store computer programs;

[0030] A processor is used to implement the steps of the vehicle braking control method described above when executing the computer program.

[0031] To address the aforementioned technical problems, the present invention also provides a power domain controller, including the aforementioned vehicle braking control device.

[0032] To solve the above-mentioned technical problems, the present invention also provides a vehicle, including the above-mentioned power domain controller, and further including a hydraulic retarder, a battery management unit, a drive motor controller and a speed control switch;

[0033] The power domain controller is connected to the hydraulic retarder, the battery management unit, and the drive motor controller via a CAN bus, and is also connected to the retarder / speed control switch to receive the switching signal sent by the retarder / speed control switch.

[0034] This application provides a vehicle braking control method, device, power domain controller, and vehicle, relating to the field of vehicle control. The method includes determining whether the execution conditions for a downhill speed control function are met; if the execution conditions are met, determining the total braking force required by the vehicle; determining the electric braking force that the vehicle can provide at the current speed; controlling the electric brake to provide electric braking force; and controlling the hydraulic retarder to compensate for the difference between the total braking force and the electric braking force. In addition to retaining the electric brake as the primary braking method, the hydraulic retarder compensates for the insufficient braking force of the electric brake. This braking force distribution allows the vehicle to descend a slope under heavy load at a set speed, ensuring both the vehicle's economy and maximizing the use of electro-regenerative braking, while also ensuring vehicle safety. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the prior art and embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A flowchart of a vehicle braking control method provided by the present invention;

[0037] Figure 2 A schematic diagram of the structure of a vehicle braking control device provided by the present invention;

[0038] Figure 3 This is a structural schematic diagram of a vehicle provided by the present invention. Detailed Implementation

[0039] The core of this invention is to provide a vehicle braking control method, device, power domain controller, and vehicle. In addition to retaining electric braking as the primary braking method, a hydraulic retarder is used to compensate for the insufficient braking force of the electric brakes. This braking force distribution allows the vehicle to descend a slope under heavy load at a set speed, ensuring both the vehicle's economy and maximizing the use of electro-regenerative braking, while also guaranteeing vehicle safety.

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Figure 1 A flowchart of a vehicle braking control method provided by the present invention is included, comprising:

[0042] S11: Determine whether the execution conditions for the downhill constant speed function are met; if so, proceed to step S12.

[0043] S12: Determine the total braking force required by the vehicle;

[0044] S13: Determine the electric braking force that the vehicle can provide at the current speed;

[0045] S14: Control the electric brake to provide electric braking force;

[0046] S15: Control the hydraulic retarder braking to compensate for the difference between the total braking force and the electric braking force.

[0047] New energy vehicles, especially new energy heavy trucks, rely more and more on coasting braking energy feedback when going downhill under heavy loads. This braking method can reduce the heat generation of friction pads and improve the safety factor of the whole vehicle. On the other hand, the feedback energy can be reused to improve the economy of the whole vehicle. However, this method has its drawbacks. The coasting braking feedback capability has an upper limit, which is limited by the motor capability and battery capability, resulting in insufficient electric braking force in some ultra-heavy downhill scenarios.

[0048] When performing coasting braking, existing solutions are limited by component configuration and can only rely on the drive motor and generator to brake and provide braking energy feedback. Once the required feedback power or torque exceeds the upper limit of the drive motor and generator, there are no other available compensation devices. The hydraulic retarder added in this invention can provide additional compensation when the available feedback capacity of the drive motor and generator is insufficient. However, the relevant technology does not provide a solution for the distribution method between the hydraulic retarder and the electric brake.

[0049] Electric brakes utilize electromagnetic induction to generate eddy currents, which dissipate kinetic energy through friction between the eddy currents and the metal disc, thus achieving deceleration. Hydraulic retarders dissipate energy through the flow resistance and hydraulic coupling of fluid (oil) between the stator and rotor, eliminating physical friction. Specifically, the system first performs coordinated braking in scenarios where the vehicle is descending a slope and needs to brake at a fixed speed. Only when this condition is met is the total braking force required for the vehicle determined. In other words, coordinated braking only occurs when the user requires the vehicle to brake at a certain speed. Once the conditions are met, the system replaces manual speed control, aiming to maintain the set speed. Without the driver needing to press the accelerator or brake, the system counteracts the speed increase caused by downhill inertia by adjusting power output (e.g., reducing fuel supply) or using auxiliary braking (e.g., engine braking).

[0050] It should be noted that the total braking force is related to the vehicle's current speed and target speed. The greater the difference between the current speed and the target speed, the greater the required total braking force. The total braking force is provided by both the electric brakes and the hydraulic retarder. Since the electric brakes are the primary force, they are first controlled to provide maximum braking force, and then supplemented by the hydraulic retarder. In this way, the electric brakes and the hydraulic retarder can work together to provide the total braking force.

[0051] This application provides a vehicle braking control method, relating to the field of vehicle control, including determining whether the execution conditions for a downhill speed control function are met; if the execution conditions are met, determining the total braking force required by the vehicle; determining the electric braking force that the vehicle can provide at the current speed; controlling the electric brake to provide electric braking force; and controlling the hydraulic retarder to compensate for the difference between the total braking force and the electric braking force. In addition to retaining the electric brake as the primary braking method, the hydraulic retarder compensates for the insufficient braking force of the electric brake. This braking force distribution allows the vehicle to descend a slope under heavy load at a set speed, ensuring both the vehicle's economy and maximizing the use of electro-regenerative braking, while also ensuring vehicle safety.

[0052] Based on the above embodiments:

[0053] In some embodiments, determining whether the execution conditions for the downhill cruise control function are met includes:

[0054] Determine whether the vehicle speed is greater than the set speed, whether the accelerator and brake pedals are pressed, whether the cruise control switch is pressed, and whether the slope of the road where the vehicle is located is less than the set slope.

[0055] If the speed is greater than the set speed, the accelerator and brake are not pressed, the cruise control switch is pressed, and the slope is less than the set slope, then the conditions for the downhill cruise control function are met.

[0056] When driving downhill, if the vehicle has a certain speed, and neither the accelerator nor the brake is applied, and the cruise control switch is activated, then the conditions for the downhill cruise control function are met. Specifically, the conditions are: vehicle speed greater than the set value, no accelerator applied, no brake applied, cruise control switch pressed, and gradient less than the set value (negative gradient for downhill driving). Once all these conditions are met, the downhill cruise control function is activated.

[0057] A speed exceeding the set speed is a prerequisite for triggering the function, ensuring it only activates when speed limiting is required and preventing accidental triggering at low speeds. The accelerator and brake pedals not being pressed confirms the driver has no intention of actively controlling the speed. The cruise control switch being pressed indicates a driver command, preventing operational conflicts caused by automatic system activation. A gradient less than the set gradient confirms the current downhill condition, preventing operational errors.

[0058] Furthermore, upon detecting changes in status, the system immediately adjusts its execution strategy or disengages the function, prioritizing driver control. If the driver presses the accelerator / brake, deactivates the cruise control switch, or the gradient exceeds the set value, cruise control disengages, and the driver takes control of the vehicle.

[0059] In some embodiments, determining the total braking force required by the vehicle includes:

[0060] Determine the target speed for the vehicle;

[0061] Determine the vehicle's real-time speed;

[0062] The total braking force required by the vehicle is determined based on the speed difference between the real-time vehicle speed and the target vehicle speed.

[0063] The vehicle speed at the moment the PMS (Powertrain Management System) lockout function is activated is the target vehicle speed V1; the real-time vehicle speed is V2; the speed difference between V2 and V1 is used as the input for the PI module to calculate the total braking force F1 required to maintain the target vehicle speed in real time.

[0064] Subtracting the target speed from the real-time vehicle speed gives the extent to which the current speed exceeds the target speed. A larger deviation indicates a more pronounced excessive speed due to downhill inertia, requiring stronger braking force; a smaller deviation requires weaker braking force, or even no additional braking at all. The system uses the speed difference as the core basis to match the corresponding braking force level. For example, when the real-time speed is 5 km / h faster than the target, a medium braking force is output; when it's 10 km / h faster, a stronger braking force is output to ensure the vehicle speed is quickly brought back to the target value.

[0065] If the vehicle speed is close to or equal to the target value, only a weak braking force will be output or no braking force will be output to avoid excessive braking that would cause the vehicle speed to fall below the set value.

[0066] In some embodiments, determining the total braking force required by the vehicle based on the speed difference between the real-time vehicle speed and the target vehicle speed includes:

[0067] Determine the speed difference between the real-time vehicle speed and the target vehicle speed;

[0068] The total braking force required by the vehicle is determined according to the braking force calculation formula, which is u(k)=Kp×Δv(k)+Ki×Ts×ΣΔv(i);

[0069] Where u(k) is the total braking force at time k, Kp is the proportional coefficient, Δv(k) is the speed difference at time k, Ki is the integral coefficient, Ts is the sampling period, and ΣΔv(i) is the cumulative sum of vehicle speed deviations from the initial time to time k.

[0070] When the vehicle speed exceeds the target speed, the PI algorithm is used to calculate the total braking force required by the vehicle based on the speed difference.

[0071] First, the difference between the real-time vehicle speed and the target vehicle speed (Δv = target vehicle speed - real-time vehicle speed) is obtained and used as the input signal for the PI controller. The proportional term (P) directly outputs the control quantity according to the magnitude of the deviation, providing a fast response to the deviation; the integral term (I) accumulates the deviation over time to eliminate static errors. The PI calculation result is then limited to the effective range of the actuator and converted into specific control commands.

[0072] Increasing the proportional coefficient (Kp) can speed up the response, but too much of it can cause vehicle speed oscillations; decreasing it will result in a slow response and slower deviation elimination.

[0073] Increasing the integral coefficient (Ki) can quickly eliminate static deviations, but excessively increasing it will exacerbate oscillations; decreasing it will make it difficult to eliminate static errors.

[0074] By combining real-time feedback from the PI system (such as the amplitude of vehicle speed fluctuations), Kp and Ki are adaptively fine-tuned to avoid control inaccuracies caused by load changes (such as climbing hills or headwinds).

[0075] In some embodiments, determining the electric braking force that the vehicle can provide at the current vehicle speed includes:

[0076] At the current vehicle speed, the available electric braking force is determined based on the upper limit of the vehicle's power battery and the upper limit of the vehicle's drive system.

[0077] The PMS receives the deceleration and speed control switch signal, as well as the upper limit of braking capacity, the upper limit of regenerative braking capacity of the drive motor, the maximum allowable regenerative braking value of the battery, and the vehicle speed signal reported by the hydraulic retarder via the CAN bus.

[0078] In some embodiments, before controlling the hydraulic retarder to compensate for the difference between the total braking force and the electric braking force, the method further includes:

[0079] Determine whether the electric braking force is less than the total braking force;

[0080] If the electric braking force is less than the total braking force, the process proceeds to control the hydraulic retarder to compensate for the difference between the total braking force and the electric braking force.

[0081] In some embodiments, after determining whether the electric braking force is less than the total braking force, the method further includes:

[0082] If the electric braking force is greater than or equal to the total braking force, then only the electric brake provides the braking force.

[0083] Braking force is preferentially allocated to the drive motor for electric braking. When the electric braking force is insufficient to stop the vehicle and maintain the target speed, a hydraulic retarder is used for compensation to control the vehicle speed from exceeding the target speed. Because the braking force is preferentially allocated to the electric brakes, braking energy is utilized to the maximum extent, ensuring the vehicle's economy while also taking safety into account.

[0084] Specifically, after the total braking force is calculated, the braking force is distributed. If, at the current vehicle speed, the allowable electric braking force F2, calculated based on the upper limit of the power battery's feedback capacity and the upper limit of the drive system's feedback capacity, can cover the total braking force F1 requirement, then the total braking force F1 is entirely allocated to the electric brakes; if the total braking force F1 > F2, the difference F3 between F1 and F2 is allocated to the hydraulic retarder, thereby achieving coordinated operation between the drive system's electric brakes and the hydraulic retarder.

[0085] Figure 2 This is a schematic diagram of a vehicle braking control device provided by the present invention. The vehicle braking control device includes:

[0086] Memory 21 is used to store computer programs;

[0087] The processor 22 is used to execute the steps of the vehicle braking control method described above when executing a computer program.

[0088] The description of the vehicle braking control device provided in this application is similar to that in the above embodiments and will not be repeated here.

[0089] The present invention also provides a power domain controller, including the vehicle braking control device described above.

[0090] The description of the power domain controller provided in this application is based on the above embodiments and will not be repeated here.

[0091] Figure 3The present invention provides a structural schematic diagram of a vehicle, which includes the aforementioned power domain controller, as well as a hydraulic retarder, a battery management unit, a drive motor controller, and a speed control switch.

[0092] The power domain controller communicates with the hydraulic retarder, battery management unit, and drive motor controller via a CAN bus. It is also connected to the retarder / speed controller switch to receive the switching signals sent by the retarder / speed controller switch.

[0093] The Power Domain Controller (PMS) acts as the control center, undertaking the logical calculations for achieving its functions. The PMS collects information from the vehicle's battery system, drive system, and hydraulic retarder, acquiring data such as vehicle speed, the upper limit of battery feedback capability, the upper limit of drive system feedback capability, and the braking capacity of the hydraulic retarder. Specifically, the PMS obtains signals such as the vehicle's battery feedback capability, drive motor feedback capability, vehicle speed, and retarder / cruise control switch via the CAN bus and hard-wired I / O inputs.

[0094] Please refer to the above embodiments for a description of the vehicle provided in this application; it will not be repeated here.

[0095] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0096] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0097] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A vehicle braking control method, characterized in that, include: Determine whether the execution conditions for the downhill constant speed function are met; If the execution conditions are met, the total braking force required by the vehicle is determined. Determine the electric braking force that the vehicle can provide at the current speed; Control the electric brake to provide the electric braking force; The hydraulic retarder is controlled to compensate for the difference between the total braking force and the electric braking force.

2. The vehicle braking control method as described in claim 1, characterized in that, The conditions for determining whether the downhill cruise control function is met include: Determine whether the vehicle's speed is greater than the set speed, whether the vehicle's accelerator and brake are depressed, whether the cruise control switch is pressed, and whether the slope of the road where the vehicle is located is less than the set slope. If the speed is greater than the set speed, the accelerator and the brake are not depressed, the cruise control switch is pressed, and the slope is less than the set slope, then the conditions for the downhill cruise control function are met.

3. The vehicle braking control method as described in claim 1, characterized in that, Determine the total braking force required by the vehicle, including: Determine the target speed of the vehicle; Determine the real-time speed of the vehicle; The total braking force required by the vehicle is determined based on the speed difference between the real-time vehicle speed and the target vehicle speed.

4. The vehicle braking control method as described in claim 3, characterized in that, Determining the total braking force required by the vehicle based on the speed difference between the real-time vehicle speed and the target vehicle speed includes: Determine the speed difference between the real-time vehicle speed and the target vehicle speed; The total braking force required by the vehicle is determined according to the braking force calculation formula, which is u(k)=Kp×Δv(k)+Ki×Ts×ΣΔv(i); Where u(k) is the total braking force at time k, Kp is the proportional coefficient, Δv(k) is the speed difference at time k, Ki is the integral coefficient, Ts is the sampling period, and ΣΔv(i) is the cumulative sum of vehicle speed deviations from the initial time to time k.

5. The vehicle braking control method as described in claim 1, characterized in that, Determine the electric braking force that the vehicle can provide at the current speed, including: At the current vehicle speed, the available electric braking force is determined based on the upper limit of the vehicle's power battery feedback capacity and the upper limit of the vehicle's drive system feedback capacity.

6. The vehicle braking control method according to any one of claims 1 to 5, characterized in that, Before controlling the hydraulic retarder to compensate for the difference between the total braking force and the electric braking force, the method further includes: Determine whether the electric braking force is less than the total braking force; If the electric braking force is less than the total braking force, then the process proceeds to control the hydraulic retarder to compensate for the difference between the total braking force and the electric braking force.

7. The vehicle braking control method as described in claim 6, characterized in that, After determining whether the electric braking force is less than the total braking force, the method further includes: If the electric braking force is greater than or equal to the total braking force, then the braking force is provided solely by the electric brake.

8. A vehicle braking control device, characterized in that, include: Memory, used to store computer programs; A processor, configured to implement the steps of the vehicle braking control method as described in any one of claims 1 to 7 when executing the computer program.

9. A dynamic domain controller, characterized in that, Includes the vehicle braking control device as described in claim 8.

10. A vehicle, characterized in that, Including the power domain controller as described in claim 9, it also includes a hydraulic retarder, a battery management unit, a drive motor controller, and a speed control switch; The power domain controller is connected to the hydraulic retarder, the battery management unit, and the drive motor controller via a CAN bus, and is also connected to the retarder / speed control switch to receive the switching signal sent by the retarder / speed control switch.

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