CN-121552933-B - Vehicle brake control method and device, electronic control unit, medium and vehicle

CN121552933BCN 121552933 BCN121552933 BCN 121552933BCN-121552933-B

Abstract

The application provides a vehicle braking control method and device, an electronic control unit, a medium and a vehicle, and relates to the technical field of vehicle braking control. The control method is applied to an electronic control unit in a vehicle, the vehicle further comprises a driving motor and a power battery, the method comprises the steps of obtaining the current charge state and the current single temperature of the power battery in the running process of the vehicle, determining the maximum allowable recharging power corresponding to the current battery state based on the preset mapping relation of the maximum recharging power of the power battery under different charge states and different single temperatures, determining the target limit vehicle speed corresponding to the maximum allowable recharging power based on the pre-calibrated vehicle speed-power mapping relation, and controlling the vehicle to run at the speed which is not higher than the target limit vehicle speed, so that the problem that braking force fluctuation and braking effect are unstable due to limited energy recharging power caused by the high charge state or low temperature of the battery is effectively solved, and the functional safety level and running reliability of the system are remarkably improved.

Inventors

LI FEI
QIAN XIAODONG
WANG XUEZHAO
CHENG XIAOLONG

Assignees

上海易咖智车科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260126

Claims (11)

1. A vehicle brake control method, characterized by an electronic control unit applied in the vehicle, the vehicle further comprising a drive motor and a power battery, the method comprising: acquiring the current state of charge and the current monomer temperature of the power battery in the running process of the vehicle; Determining maximum allowable recharging power corresponding to the current state of charge and the current monomer temperature based on a preset mapping relation for representing the maximum recharging power of the power battery under different states of charge and different monomer temperatures; Determining a target limit vehicle speed corresponding to the maximum allowable recharging power based on a pre-calibrated vehicle speed-power mapping relation, wherein the vehicle speed-power mapping relation is calibrated based on the external characteristic of the anti-dragging braking feed of the driving motor and is used for defining the maximum feed power which can be generated when the driving motor carries out the maximum capacity anti-dragging braking under different vehicle speeds; Determining a theoretical braking distance from the target speed limit to stopping when the vehicle is subjected to maximum capacity reverse braking under the target speed limit based on the reverse braking feed external characteristics of the driving motor, the vehicle preparation quality and the transmission system efficiency; If the theoretical braking distance is greater than a preset safe braking distance threshold, iteratively reducing the target speed limit, and redefining the corresponding theoretical braking distance until the theoretical braking distance is not greater than the safe braking distance threshold; Taking a vehicle speed satisfying the theoretical braking distance not greater than the safe braking distance threshold value as the target vehicle speed limit for control; the vehicle is controlled to travel at not higher than the target vehicle speed limit.
2. The vehicle brake control method according to claim 1, characterized in that the determining a target vehicle speed limit corresponding to the maximum allowable recharging power based on a pre-calibrated vehicle speed-power map relation includes: inquiring the vehicle speed-power mapping relation, and acquiring a maximum feed power value smaller than or equal to the maximum allowable recharging power; and determining the vehicle speed corresponding to the maximum feed power value as the target vehicle speed limit.
3. The vehicle brake control method according to claim 2, characterized in that the controlling the vehicle to travel at not higher than the target vehicle speed limit includes: A vehicle speed limit instruction is generated based on the target vehicle speed limit and output so that an actual vehicle speed of the vehicle is controlled to be below the target vehicle speed limit.
4. The vehicle brake control method according to any one of claims 1 to 3, wherein the preset map representing the maximum recharging power of the power battery in different states of charge and different temperatures of the single body and the pre-calibrated vehicle speed-power map are calibrated based on parameters of the driving motor and the power battery that satisfy a system matching condition, the system matching condition includes that the maximum direct current feeding power that the driving motor can output under a reverse braking condition is smaller than the minimum continuous recharging power of the power battery in all states of charge and a working temperature range that allows recharging.
5. A vehicle brake control method according to any one of claims 1 to 3, characterized in that the vehicle further comprises an electromagnetic brake, the method further comprising an emergency braking step: when the failure of the anti-dragging braking function of the driving motor is detected, and the current speed is lower than a preset emergency braking starting speed threshold, triggering the electromagnetic brake to carry out emergency braking.
6. The vehicle brake control method according to claim 5, characterized in that the triggering the electromagnetic brake to make an emergency brake includes: determining the upper limit of the allowable emergency braking triggering times in unit time or unit driving mileage according to the designed total service life or total mileage of the vehicle and the calibrated emergency braking service time life of the electromagnetic brake; And when the actual emergency braking triggering frequency in the current period does not exceed the upper frequency limit, executing to trigger the electromagnetic brake to perform emergency braking.
7. A vehicle brake control apparatus, characterized by an electronic control unit applied to the vehicle, the vehicle further comprising a drive motor and a power battery, the apparatus comprising: the acquisition module is used for acquiring the current state of charge and the current monomer temperature of the power battery in the running process of the vehicle; The first determining module is used for determining the maximum allowable recharging power corresponding to the current charge state and the current monomer temperature based on a preset mapping relation for representing the maximum recharging power of the power battery under different charge states and different monomer temperatures; The second determining module is used for determining a target limit vehicle speed corresponding to the maximum allowable recharging power based on a pre-calibrated vehicle speed-power mapping relation, wherein the vehicle speed-power mapping relation is calibrated based on the external characteristic of the anti-dragging braking feed of the driving motor and is used for defining the maximum feed power which can be generated when the driving motor performs maximum capacity anti-dragging braking under different vehicle speeds; the control module is used for determining a theoretical braking distance from the target speed limit to stopping when the vehicle brakes at the maximum capacity under the target speed limit based on the anti-dragging braking feed external characteristics of the driving motor, the vehicle preparation quality and the transmission system efficiency, iteratively reducing the target speed limit if the theoretical braking distance is larger than a preset safe braking distance threshold value and redetermining a corresponding theoretical braking distance until the theoretical braking distance is not larger than the safe braking distance threshold value, and controlling the vehicle to run at the target speed limit for controlling if the theoretical braking distance is not larger than the safe braking distance threshold value.
8. An electronic control unit comprising a processor and a memory communicatively coupled to the processor; the memory is used for storing computer execution instructions; The processor for executing the computer-executable instructions to implement the method of any one of claims 1 to 6.
9. A vehicle comprising an electronic control unit according to claim 8.
10. A computer readable storage medium having stored therein computer executable instructions which when executed are adapted to implement the method of any one of claims 1 to 6.
11. A computer program product comprising a computer program, characterized in that the computer program, when executed, implements the method according to any one of claims 1 to 6.

Description

Vehicle brake control method and device, electronic control unit, medium and vehicle Technical Field The present application relates to the field of vehicle brake control technologies, and in particular, to a vehicle brake control method and apparatus, an electronic control unit, a medium, and a vehicle. Background With the rapid development of automatic driving and intelligent networking technologies, unmanned vehicles are increasingly widely applied to specific scenes such as sanitation, logistics, connection and the like. The operation safety of low-speed operation vehicles such as unmanned sweeping vehicles, unmanned logistics vehicles and the like is a primary precondition for industrial landing. The brake system is used as the last defense line of the active safety of the vehicle, and the reliability, the stability and the vehicle cost of the control strategy directly determine whether the vehicle can be safely and efficiently put into actual operation. Therefore, how to achieve the optimal balance between the system cost and the maintenance convenience while satisfying the severe security standard becomes a core challenge to be solved in the field. In the related art, in order to cope with the above-mentioned challenges, for a specific scenario where the working vehicle speed is low (typically not more than 20 km/h), a simplified braking scheme of de-hydraulicity is generally adopted. The key point of the scheme is that a traditional hydraulic braking or a complex electric control hydraulic braking system (Electronic Hydraulic Braking, EHB for short) is abandoned, and the driving motor reverse towing braking (i.e. regenerative braking) is adopted as the only means for realizing the conventional service braking. The vehicle controller controls the driving motor to switch from an electric mode to a power generation mode when the vehicle needs to be decelerated, at the moment, under the inertia effect of the vehicle, wheels drive the motor rotor to rotate through the transmission system, reverse electromagnetic torque (namely braking torque) opposite to the rotating direction is generated inside the motor, the torque is fed back to the driving wheels through a transmission chain (such as a chain or a speed reducer), and therefore the vehicle is decelerated, and meanwhile part of kinetic energy is converted into electric energy to be fed back to the power battery. In addition, this solution is usually equipped with a separate electromagnetic parking brake (often integrated in the motor end cap or axle) for static parking and as an emergency backup in case of service brake failure. However, there is a problem in that the braking effect is unstable. Disclosure of Invention The application provides a vehicle braking control method and device, an electronic control unit, a medium and a vehicle, which are used for solving the problem of unstable braking effect. In a first aspect, the present application provides a vehicle brake control method applied to an electronic control unit in a vehicle, the vehicle further including a drive motor and a power battery, the method comprising: Acquiring the current charge state and the current monomer temperature of the power battery in the running process of the vehicle; Determining the maximum allowable recharging power corresponding to the current state of charge and the current single temperature based on a preset mapping relation for representing the maximum recharging power of the power battery under different states of charge and different single temperatures; determining a target limit vehicle speed corresponding to the maximum allowable recharging power based on a pre-calibrated vehicle speed-power mapping relation, wherein the vehicle speed-power mapping relation is calibrated based on the external characteristic of anti-dragging braking feeding of the driving motor and is used for defining the maximum feeding power which can be generated when the driving motor performs maximum capacity anti-dragging braking under different vehicle speeds; The control vehicle travels at not higher than the target vehicle speed limit. In one possible implementation, determining the target vehicle speed limit corresponding to the maximum allowable recharging power based on a pre-calibrated vehicle speed-power mapping relation includes inquiring the vehicle speed-power mapping relation, acquiring a maximum power supply value smaller than or equal to the maximum allowable recharging power, and determining the vehicle speed corresponding to the maximum power supply value as the target vehicle speed limit. In one possible embodiment, controlling the vehicle to travel at not higher than the target vehicle speed limit includes generating a vehicle speed limit command based on the target vehicle speed limit and outputting such that an actual vehicle speed of the vehicle is controlled below the target vehicle speed limit. In one possible implementation, before controlling the vehicle to ru