Vehicle braking control method and device, new energy vehicle and storage medium

Abstract

The invention relates to a vehicle braking control method and device, a new energy vehicle and a storage medium, and relates to the technical field of new energy vehicles. The method includes determining a target deceleration when an electric braking function of a vehicle is activated; the motor output torque is adjusted through first PID control based on the target deceleration, so that the vehicle is gradually decelerated; and under the condition that the vehicle slows down to a preset vehicle speed threshold value, the target deceleration is updated to be zero, the motor output torque continues to be adjusted through the first PID control based on the updated target deceleration, the target vehicle speed is set to be zero, and the motor output torque is adjusted through the second PID control based on the target vehicle speed so as to control vehicle braking. By means of the method, the smoothness and safety of the vehicle in the electric braking process can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of new energy vehicles, and in particular to a vehicle braking control method, device, new energy vehicle, storage medium and computer program product. Background Art

[0002] New energy vehicle technology is updated day by day, and it is very necessary to improve the safety of new energy vehicles, especially the safety of the vehicle's braking process.

[0003] At present, the braking control of the vehicle is mainly carried out by the driver operating the braking system. However, in the event of a failure of the braking system, in order to ensure that the vehicle has sufficient deceleration, the maximum recovery torque available from the motor is generally used as the target torque for electric braking. However, the current vehicle condition and braking environment of the vehicle are relatively complex. Adjusting the motor based on the maximum recovery torque available from the motor may make it difficult to ensure effective braking of the vehicle, which is not conducive to driving safety. Summary of the invention

[0004] Based on this, it is necessary to provide a vehicle braking control method, device, new energy vehicle, computer-readable storage medium and computer program product to address the above technical problems.

[0005] In a first aspect, the present application provides a vehicle braking control method, comprising:

[0006] determining a target deceleration with an electric brake function of the vehicle activated;

[0007] Based on the target deceleration, the motor output torque is adjusted by the first PID control so that the vehicle gradually decelerates at the target deceleration;

[0008] When the vehicle decelerates to a preset speed threshold, the target deceleration is updated to zero. Based on the updated target deceleration, the motor output torque continues to be adjusted through the first PID control, and the target vehicle speed is set to zero. Based on the target vehicle speed, the motor output torque is adjusted through the second PID control to control vehicle braking.

[0009] In one embodiment, based on the target deceleration, adjusting the motor output torque through a first PID control includes:

[0010] Obtain the actual speed change rate of the vehicle;

[0011] Acquire a first difference between the target deceleration and the actual vehicle speed change rate, and a first difference change rate of the first difference;

[0012] Based on the first difference and the first difference change rate, the input of the first PID control is determined to adjust the motor output torque through the first PID control; wherein the inputs of the P item and the I item are determined based on the first difference, and the input of the D item is determined based on the first difference change rate.

[0013] In one embodiment, based on the target vehicle speed, adjusting the motor output torque through the second PID control includes:

[0014] Get the actual ground speed of the vehicle;

[0015] determining a second difference between the target vehicle speed and the actual vehicle speed over the ground, and a second difference change rate of the second difference;

[0016] The input of the second PID control is determined based on the second difference and the second difference change rate to adjust the motor output torque to control vehicle braking; wherein the inputs of the P item and the I item are determined based on the second difference, and the input of the D item is determined based on the second difference change rate.

[0017] In one embodiment, obtaining the actual speed change rate of the vehicle includes:

[0018] Determining a vehicle speed based on a motor speed of the vehicle;

[0019] Determine the vehicle's ground speed based on the vehicle's direction of travel and speed; the direction of travel is forward or reverse;

[0020] The actual speed change rate of the vehicle is obtained by taking the derivative of the ground speed.

[0021] In one embodiment, it also includes:

[0022] The vehicle's driving direction is determined based on the wheel speed direction when any of the following conditions are met:

[0023] The vehicle speed is less than the preset forward speed;

[0024] The vehicle's direction of travel changes.

[0025] In one embodiment, when an electric braking function of a vehicle is activated, determining a target deceleration includes:

[0026] When the electric brake function of the vehicle is activated, the target deceleration is determined based on the vehicle's current ground speed, the slope of the road surface and a preset mapping table.

[0027] In one embodiment, it also includes:

[0028] Determine the slope of the road on which the vehicle is located based on the first method and / or the second method;

[0029] In the first mode, an intermediate value is determined based on the vehicle speed over the ground, the wheel end torque and the tire radius, and the slope is determined by looking up the table based on the intermediate value;

[0030] In the second mode, an intermediate value is determined based on the vehicle speed relative to the ground, the wheel end torque and the tire radius, and the intermediate value is substituted into a preset calculation model to determine the slope.

[0031] In one embodiment, determining the slope of the road on which the vehicle is located based on the first method and / or the second method includes:

[0032] Acquire multiple slopes determined based on the second method within a preset time before the current time;

[0033] When the variance values ​​of the multiple slopes are less than the set variance threshold, the second method is selected to determine the slope; otherwise, the first method is selected to determine the slope.

[0034] In one embodiment, it also includes:

[0035] The electric brake function is activated when at least one of the following conditions is met;

[0036] A first condition that the key pressing duration of a target key of the vehicle is greater than a preset duration threshold;

[0037] A second condition that the number of key presses on the target key within a preset time period is greater than a preset key press number threshold;

[0038] The third condition is that the relative distance between the vehicle and the preceding vehicle is less than a preset relative distance threshold, and the relative speed is greater than a preset relative speed threshold.

[0039] In one embodiment, it also includes:

[0040] When the accelerator pedal opening is greater than the preset proportional value or the vehicle speed over the ground is less than the preset reverse speed, the electric braking function is exited.

[0041] In a second aspect, the present application provides a vehicle braking control device, comprising:

[0042] A first regulating module is used to determine a target deceleration when the electric brake function of the vehicle is activated; based on the target deceleration, the motor output torque is adjusted through a first PID control so that the vehicle gradually decelerates with the target deceleration as the target;

[0043] The second adjustment module is used to update the target deceleration to zero when the vehicle decelerates to a preset vehicle speed threshold, and based on the updated target deceleration, continue to adjust the motor output torque through the first PID control, and set the target vehicle speed to zero, and based on the target vehicle speed, adjust the motor output torque through the second PID control to control vehicle braking.

[0044] In a third aspect, the present application provides a new energy vehicle, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of any of the methods described above when executing the computer program.

[0045] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of any of the methods described above.

[0046] In a fifth aspect, the present application provides a computer program product, including a computer program, which implements the steps of any of the methods described above when executed by a processor.

[0047] The above-mentioned vehicle braking control method, device, new energy vehicle, storage medium and computer program product, when the electric braking function of the vehicle is activated, determine the target deceleration, adjust the motor output torque through the first PID control based on the target deceleration, so that the vehicle gradually decelerates with the target deceleration as the target; when the vehicle decelerates to a preset vehicle speed threshold, update the target deceleration to zero, continue to adjust the motor output torque through the first PID control based on the updated target deceleration, and in this stage, set the target vehicle speed to zero, and adjust the motor output torque through the second PID control based on the target vehicle speed to control the vehicle to stop. In the above manner, the motor torque is closed-loop controlled by the target deceleration during the deceleration stage, and the target deceleration is adjusted and the motor torque is closed-loop controlled by the two factors of the target deceleration and the target speed when the vehicle speed is reduced to a near-stationary stage. The target deceleration can keep the vehicle deceleration consistent in different scenarios, and the target speed can keep the vehicle stationary on the slope, thereby improving the riding experience during the vehicle deceleration process and ensuring the safety of the vehicle when it is parked. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 A diagram showing an application environment of a vehicle braking control method in an embodiment;

[0050] Figure 2 A schematic flow chart of a vehicle braking control method in one embodiment;

[0051] Figure 3 It is a schematic diagram of a process of controlling the motor torque based on the target deceleration PID in one embodiment;

[0052] Figure 4 It is a schematic diagram of a process of controlling the motor torque based on the target vehicle speed PID in one embodiment;

[0053] Figure 5 A schematic flow chart of a vehicle braking control method in another embodiment;

[0054] Figure 6 is a structural block diagram of a vehicle brake control device in one embodiment;

[0055] Figure 7 1 is a structural diagram of a new energy vehicle in one embodiment. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0057] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0058] Before starting to describe the embodiments of the present application in detail, the terms / nouns involved in the embodiments of the present application are explained as follows.

[0059] The three-dimensional coordinate system of a car has three directions: the lateral x direction refers to the left and right direction of the vehicle; the longitudinal y direction refers to the front and back direction of the vehicle; the up and down direction (vertical direction) of the vehicle is the z direction; among them, the synthesis of the lateral speed and the longitudinal speed is the speed of the vehicle.

[0060] The yaw rate of a vehicle refers to the speed at which the vehicle rotates around a vertical axis; the yaw rate describes the speed at which the vehicle rotates when turning.

[0061] D gear (Drive gear): The vehicle's forward gear. Normally, the motor should rotate forward at this time and the motor speed should be a positive value. If the motor rotates backward at this time, it indicates that the motor is reversed.

[0062] R gear (Reverse gear): The reverse gear of the vehicle. Under normal circumstances, the motor should rotate backward at this time and the motor speed should be a negative value; if the motor rotates forward at this time, it indicates that the motor is reversed.

[0063] The vehicle speed is related to the motor speed through the transmission system, and the two are directly proportional. For example, when the motor speed increases, the vehicle speed will increase accordingly.

[0064] Motor torque, also known as the output torque of the motor, is one of the basic parameters of the motor and is commonly expressed in Nm (Newton-meter). The motor speed and output torque are usually inversely proportional. For example, at starting or low speed, the vehicle speed is low, the motor speed is low, and the motor output torque is high to provide sufficient driving force to overcome inertia and resistance; at high speed, the vehicle speed is high, the motor speed is high, and the output torque is low to meet cruising needs while improving efficiency. The maximum available recovery torque of the motor refers to the maximum value of the negative torque generated by the motor during energy recovery. When the driver releases the accelerator pedal or steps on the brake pedal, the motor control will generate a negative torque to slow down the car and achieve energy recovery. The size of this value depends on factors such as the vehicle's control strategy, driving status, and the battery's energy storage capacity.

[0065] The target torque of electric braking is divided into deceleration torque and hill-holding torque. Generally speaking, the deceleration torque, dynamic torque or braking torque is used when the vehicle is dynamic, and the hill-holding torque is used when the vehicle is static. The hill-holding torque can make the vehicle stationary on different slopes. The main goal of the braking torque is deceleration, which can be dynamically adjusted according to the deceleration requirements. The braking torque can occur at various speeds of the vehicle and is not limited to use when stopped. The main function of the hill-holding torque is not to decelerate the vehicle, but to maintain the vehicle's stationary state. It is usually applied when the vehicle speed is low or even close to 0. In some cases, the hill-holding torque can be continuously increased from 0 to ensure that the vehicle remains as stationary as possible on uphill or downhill road conditions, thereby obtaining a suitable hill-holding torque.

[0066] Stalled rotor: A situation in which the motor still outputs torque when the speed is 0 rpm.

[0067] The vehicle braking control method provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown, the vehicle includes a cockpit software system 101, a vehicle interconnection terminal T-BOX (Telematics BOX) 102, a vehicle controller 103, a traditional braking system 104, a power battery system 105, a motor and a motor controller 106, etc. connected via a bus 100.

[0068] The cockpit software system 101 can be used to control the user interface in the car, including the instrument panel, touch screen, entertainment system and navigation system, and provide interactive functions for the driver and passengers.

[0069] As the vehicle's telematics unit, T-BOX 102 can connect the vehicle and the cloud through a communication network and is responsible for collecting, uploading and remotely controlling vehicle data.

[0070] The vehicle controller 103, as the brain of the new energy vehicle, is responsible for coordinating and controlling the operation of components such as batteries, motors, motor controllers, and thermal management systems, to achieve intelligent control of the vehicle's power distribution, energy management, and vehicle functions.

[0071] The conventional braking system 104, including the conventional brake system, mainly controls the deceleration and parking process of the vehicle by adjusting the clamping torque.

[0072] The power battery system 105 is mainly used to provide a main power source for the vehicle and to provide power for the motor when driving.

[0073] The motor and motor controller 106, where the motor is the core component that converts electrical energy into mechanical energy and provides power when the vehicle is driving, and the motor controller is responsible for controlling the speed and torque output of the motor. It receives instructions from the vehicle control system and adjusts the working state of the motor so that the motor can achieve the functions of acceleration, deceleration and braking. Specifically, the motor controller can change the working state of the motor by adjusting the current and voltage, and decide whether the motor drives the vehicle forward or recovers energy.

[0074] Among them, the motor and the motor controller 106 can also constitute an electric braking system. The electric braking system can be understood as adjusting the reverse torque of the motor through the motor controller to achieve vehicle deceleration or parking. In this process, the vehicle is braked by converting electrical energy into mechanical energy. The principles involved include energy recovery and braking control. Energy recovery can be understood as when the vehicle decelerates or stops, the motor controller controls the motor to generate reverse torque, converts the vehicle's kinetic energy into electrical energy, and stores it back in the battery, thereby extending the cruising range. This control method can reduce dependence on traditional mechanical brakes. Correspondingly, the electric braking process can be understood as the process of braking the vehicle mainly through the electric braking system.

[0075] For new energy vehicles, braking can be performed through the traditional braking system. When the traditional braking system fails, in order to ensure driving safety, the electric braking function can be activated, so that the electric braking of the vehicle can be achieved through the motor. In the embodiment of the present application, when the electric braking function of the vehicle is activated, a target deceleration is first determined, and the motor output torque is adjusted by the closed-loop control method with the target deceleration as the target, that is, this stage is mainly to make the vehicle gradually decelerate with the target deceleration as the target; when the vehicle gradually decelerates to the preset vehicle speed threshold (close to 0), the target deceleration is updated to 0, and the motor output torque is continued to be adjusted by the closed-loop control method based on the updated target deceleration. At the same time, this stage also sets the target vehicle speed to zero, takes the target vehicle speed as the vehicle speed control target, and adjusts the motor output torque through another closed-loop control, that is, this stage controls the motor torque with the target deceleration as 0 and the target vehicle speed as 0 at the same time to control the vehicle to stop completely, thereby achieving the stability and safety of the vehicle electric braking process.

[0076] In an exemplary embodiment, Figure 2 As shown, a vehicle braking control method is provided, which is applied to Figure 1 The vehicle controller of the vehicle in the embodiment is used as an example for explanation. In other embodiments, the method can also be implemented by a motor controller, or by a vehicle controller and a motor controller in cooperation. The method includes the following steps S201 to S203. Among them:

[0077] S201 , when the electric brake function of the vehicle is activated, determining a target deceleration.

[0078] Among them, the electric braking function and the activation conditions of the electric braking function can be pre-configured in the vehicle in the present application. The electric braking function can be understood as a function of controlling vehicle braking based on the above-mentioned electric braking system. When this function is activated, it can replace the traditional braking system to achieve vehicle deceleration and parking. The activation conditions of the electric braking function can include one or more conditions.

[0079] In the embodiment of the present application, the motor under the electric braking function is the same motor as the motor during normal driving of the vehicle. It can be understood that the electric braking function and the vehicle driving function are two working modes of the motor. The motor can switch to the electric braking function mode based on the preset activation conditions and return conditions of the electric braking function, or exit the electric braking function mode and switch to the vehicle driving function mode.

[0080] The target deceleration is a control target used during vehicle deceleration, which means that the system wants the vehicle to gradually decelerate at a certain speed. Its unit can be m / s². Its application scenario, for example, when the driver steps on the brake or the braking system starts working, the system will calculate an ideal deceleration, which is a target value. The purpose is to allow the vehicle to gradually slow down without sudden deceleration. The system will continuously monitor the actual deceleration of the vehicle and adjust the braking torque to maintain the target deceleration, so as to achieve smooth braking of the vehicle. For example: the vehicle's ground speed gradually decelerates from 60 km / h to 15 km / h, and a target deceleration is set to decelerate by 1 m / s² per second, that is, the target deceleration is -1 m / s². The system continuously adjusts the braking force to maintain this deceleration to ensure a smooth speed process.

[0081] In some embodiments, during vehicle driving, the vehicle controller can obtain multiple status information of the vehicle in real time or periodically, and determine whether the activation conditions of the electric braking function are met based on one or more of the multiple status information. If it is determined that the activation conditions are met, the aforementioned electric braking function can be activated.

[0082] In some embodiments, during the driving process of the vehicle, the vehicle controller obtains multiple status information of the vehicle in real time, matches the multiple status information with the activation conditions of the electric brake function, and determines whether the activation conditions of the electric brake function are met. If they are met, the electric brake function is activated, and a preset target deceleration can be immediately obtained thereafter, or a target deceleration can be determined in real time based on the detection data of the vehicle; after the electric brake function is activated, if it is detected that the actual ground speed of the vehicle has decelerated to the preset speed, a target deceleration can be determined by looking up a table based on the ground speed and the current road slope, or a target deceleration can be determined in real time based on the detection data of the vehicle.

[0083] In an embodiment of the present application, when the vehicle is in the deceleration stage and the ground speed is greater than a set threshold (the threshold can be set to a value greater than 0 km / h and less than or equal to 10 km / h, such as 10 km / h or 5 km / h), the target deceleration is a negative value, such as -1 m / s², -1.5 m / s² or -2 m / s², etc.

[0084] S202: Based on the target deceleration, the motor output torque is adjusted by a first PID (Proportional-Integral-Derivative Control) control so that the vehicle gradually decelerates with the target deceleration as the target.

[0085] Among them, PID control is a feedback control (closed-loop control) system, which is mainly used to automatically adjust the output to reach the expected value. It consists of three parts: proportional (P), integral (I) and differential (D), which respectively control the size, accumulation and change trend of the error. The system is adjusted through the three parts of proportional (P), integral (I) and differential (D) to achieve the control target. Its principle includes: the PID controller calculates the error by comparing the set target value and the actual output value of the system, and divides the error signal into three parts for processing: (1) Proportional part: directly reflects the size of the error in proportion and quickly reduces the error. (2) Integral part: eliminates static error. (3) Differential part: reflects the change trend of the error, adjusts in advance, and reduces oscillation. Through the linear combination of these three parts, the PID controller can effectively adjust the system to achieve the set target. PID closed-loop control means that the system will automatically adjust until the error between the target value and the actual value is close to zero.

[0086] In one embodiment, the target deceleration is used as the control target of the vehicle deceleration process, and the motor output torque is adjusted through the first PID control in combination with the deviation between the actual vehicle speed change rate and the control target. In this way, the motor output torque of the vehicle can be automatically adjusted to make the vehicle decelerate smoothly. The actual vehicle speed change rate refers to the change rate of the actual vehicle speed relative to the ground.

[0087] S203, when the vehicle decelerates to a preset speed threshold, the target deceleration is updated to zero, and based on the updated target deceleration, the motor output torque continues to be adjusted through the first PID control, and the target vehicle speed is set to zero. Based on the target vehicle speed, the motor output torque is adjusted through the second PID control to control vehicle braking.

[0088] Among them, the target speed, also known as the target ground speed, is the control target when the vehicle is close to a complete stop, and its unit is generally km / h or m / s. At this stage, the system's goal is not to slow down the vehicle again, but to keep the vehicle stationary at zero speed (0 km / h). Its application scenario is that when the vehicle is close to a stop (the speed is close to 0), the system no longer pays attention to the deceleration, but begins to pay attention to the vehicle's ground speed, hoping to keep the ground speed at zero. The goal is to keep the vehicle from sliding and stable after stopping. The system will set a target speed (usually 0 km / h) and make slight adjustments to the braking force to ensure that the vehicle can remain stationary and avoid sliding or slight movement. For example: when the vehicle decelerates from 10 km / h to 1 km / h, the motor output torque is controlled at the target speed, with the aim of keeping the vehicle completely stopped without slipping.

[0089] Among them, the first PID control and the second PID control indicate that there are at least two PID controls in the system at this stage, that is, this stage is a multi-PID control process, which can be implemented by one or more PID controllers, and each PID controller is responsible for controlling one or more variables. In the embodiment of the present application, the first PID control is responsible for the deceleration variable, and the second PID control is responsible for the vehicle speed variable. Compared with a single PID control, the multi-PID control method can handle more complex system situations.

[0090] In one embodiment, the vehicle controller can detect the vehicle's ground speed in real time. When the ground speed has decelerated to a preset speed threshold (e.g., 1 km / h), the target deceleration is updated to zero, the motor output torque is adjusted based on the updated target deceleration and the first PID control, and the target speed is set to zero. The motor output torque is adjusted based on the target speed and the second PID control to control the vehicle to stop and prevent the vehicle from sliding or rolling down a slope.

[0091] Based on the method of the above embodiment, when the electric brake function of the vehicle is activated, in the first stage, the motor output torque is controlled in a closed loop mainly through the target deceleration to decelerate the vehicle smoothly. In the second stage, the target deceleration is updated to zero and the target vehicle speed is set to zero. The motor output torque is controlled in a closed loop through the two factors of the target deceleration and the target vehicle speed to stop the vehicle. That is, in the vehicle deceleration stage, the motor torque is controlled in a closed loop through the target deceleration, and in the near-stationary stage, the target deceleration is adjusted and the motor torque is controlled in a closed loop through the two factors of the target deceleration and the target speed. The target deceleration can keep the vehicle deceleration consistent in different braking scenarios, and the target speed can keep the vehicle parked on the slope. Based on this, the riding experience during the vehicle braking process is improved, and the parking safety of the vehicle can be guaranteed.

[0092] In one embodiment, referring to Figure 3 As shown, based on the target deceleration, the method of adjusting the motor output torque through the first PID control may include:

[0093] Step S301, obtaining the actual speed change rate of the vehicle.

[0094] In the embodiment of the present application, the vehicle speed change rate is sometimes also referred to as acceleration or deceleration, both of which characterize the change of vehicle speed over time, and its unit may be m / s². During the process of the vehicle being braked by motor control, the actual acceleration or actual vehicle speed change rate of the vehicle may be obtained in real time or periodically.

[0095] In a specific embodiment, the actual speed change rate of the vehicle can be obtained by:

[0096] The motor speed of the vehicle is obtained, and the vehicle speed is determined based on the motor speed; the driving direction of the vehicle is obtained, and the driving direction is forward or reverse; the vehicle's speed relative to the ground is determined based on the vehicle's driving direction and speed; the speed relative to the ground is derived to obtain the actual speed change rate of the vehicle.

[0097] Compared with the longitudinal acceleration collected by the sensor installed on the vehicle, the collected longitudinal acceleration is related to the posture of the sensor. For example, when the vehicle is on a slope, the sensor may be in a non-horizontal state, and the collected longitudinal acceleration may not be accurate enough. The actual vehicle speed change rate calculated based on the vehicle's ground speed in the embodiment of the present application is the real acceleration of the vehicle. Based on this, the input of the PID control is determined to ensure the accuracy of the PID adjustment.

[0098] Step S302, obtaining a first difference between the target deceleration and the actual vehicle speed change rate, and a first difference change rate of the first difference.

[0099] Among them, when the vehicle controller can obtain the actual speed change rate of the vehicle in real time or periodically, each time the actual speed change rate of the vehicle is newly obtained, a difference between the target deceleration and the actual speed change rate can be obtained. Based on the difference obtained multiple times, the first difference change rate can be obtained. For example, the difference between the target deceleration and the actual speed change rate determined last time is 0.2m / s², and the difference between the target deceleration and the actual speed change rate determined next time is 0.1m / s². The time difference between the two times is 1 second, then the difference change rate corresponding to the two times can be recorded as 0.1 m / s 3 .

[0100] Step S303: determining an input of a first PID control based on the first difference and the first difference change rate, so as to adjust the motor output torque through the first PID control.

[0101] The inputs of the P term and the I term of the first PID control are determined based on the first difference, and the input of the D term is determined based on the rate of change of the first difference.

[0102] In one embodiment, the vehicle controller obtains the actual speed change rate of the vehicle in real time, and determines the first difference between the target deceleration and the actual speed change rate, and the first difference change rate of the first difference based on the actual speed change rate currently obtained, and then can determine the inputs of the P item and the I item of the first PID control based on the first difference by looking up in the same mapping table or two different mapping tables, and determine the input of the D item of the first PID control based on the first difference change rate by looking up in another mapping table. By determining and adjusting each input of the first PID control in real time, and determining the specific value of each input by looking up in a table, it is simple and efficient, and the precision of the first PID regulation of the motor torque can be guaranteed.

[0103] In one embodiment, referring to Figure 4 As shown, based on the target vehicle speed, the process of adjusting the motor output torque through the second PID control may include:

[0104] Step S401, obtaining the actual ground speed of the vehicle.

[0105] The actual ground speed of the vehicle can be understood as the ground speed of the vehicle. In the embodiment of the present application, the vehicle controller can obtain the motor speed in real time or periodically, and determine the actual ground speed of the vehicle according to the motor speed and the driving direction of the vehicle.

[0106] In one embodiment, the method for obtaining the driving direction of the vehicle includes: determining the current driving direction of the vehicle based on the wheel speed direction when any of the following conditions is met: (1) the vehicle speed relative to the ground is less than a preset forward speed, for example, the vehicle speed is less than 5 km / h; (2) the vehicle's driving direction changes.

[0107] Step S402, determining a second difference between the target vehicle speed and the actual vehicle speed over the ground, and a second difference change rate of the second difference.

[0108] Wherein, when the vehicle controller can obtain the actual ground speed of the vehicle in real time or periodically, each time the actual ground speed of the vehicle is newly obtained, a difference between the target speed and the actual ground speed can be obtained. Based on the difference obtained multiple times, a second difference change rate can be obtained.

[0109] Step S403, determining an input of a second PID control based on the second difference and the second difference change rate to adjust the motor output torque to control vehicle braking.

[0110] In one embodiment, the vehicle controller obtains the actual ground speed of the vehicle in real time, and determines the second difference between the target speed and the actual ground speed, and the second difference change rate of the second difference based on the actual ground speed currently obtained, and then can determine the inputs of the P item and the I item of the second PID control based on the second difference by looking up in the same mapping table or two different mapping tables, and determine the input of the D item of the second PID control based on the second difference change rate by looking up in another mapping table. By determining and adjusting each input of the second PID control in real time, and determining the specific value of each input by looking up in a table, it is simple and efficient, and can ensure the precision of the second PID to the motor torque regulation in the scenario where the vehicle speed is the control target.

[0111] In one embodiment, the process of determining the target deceleration in the above embodiment may include: when the electric braking function of the vehicle is activated, determining the target deceleration based on the vehicle's current ground speed, the slope of the road surface, and a preset mapping table.

[0112] Among them, the method for obtaining the vehicle's current ground speed can refer to the above embodiment and be determined based on the motor speed, which will not be repeated here.

[0113] As an example, the slope of the road surface can be obtained as follows:

[0114] During the vehicle electric braking process, the vehicle controller can determine the slope of the road on which the vehicle is located based on a predefined first method and / or a second method. In the first method, an intermediate value is determined based on the vehicle speed relative to the ground, the wheel end torque and the tire radius, and the corresponding slope is determined by looking up the table based on the intermediate value; in the second method, an intermediate value is determined based on the vehicle speed relative to the ground, the wheel end torque and the tire radius, and the intermediate value is substituted into a preset calculation model to determine the slope through the calculation model.

[0115] As a specific example, based on the vehicle speed over the ground, the wheel end torque and the tire radius, the process of determining the intermediate value may be:

[0116]

[0117] in, Wheel end torque (unit: Nm), r is the tire radius of the vehicle (unit: m), is the air resistance coefficient, is the frontal area of ​​the vehicle (unit: square meters), is a constant of 1.2258, is the rotation mass conversion factor, is the vehicle speed relative to the ground (unit: km / h), m is the vehicle weight (unit: kilograms), and F1 is the intermediate value to be calculated.

[0118] As another specific example, the intermediate value is substituted into a preset calculation model, and the slope is determined by the calculation model, as shown below:

[0119]

[0120] Where m is the vehicle weight (unit: kilograms), g is the gravity coefficient, f is the rolling resistance coefficient, F1 is the calculated intermediate value, and θ represents the calculated slope (unit: degree).

[0121] The calculation formula for the above slope θ can be derived by combining the force balance when the vehicle is stationary on a slope, as described below.

[0122] The force F when standing on a slope:

[0123] F = slope resistance + rolling resistance + air resistance + acceleration resistance

[0124] Right now, = m·g·sinθ + m·g·f·cosθ+ +

[0125] ∴ The intermediate value F1 = m·g·sinθ + m·g·f·cosθ, which can be used to inversely solve for the slope θ.

[0126] It can be seen that the calculation formula for the slope θ is consistent with the force balance when the vehicle is stationary on a slope, and the current slope of the vehicle can be obtained based on the calculation formula.

[0127] In the first mode described above, the slope determination method needs to look up the table in combination with the intermediate value F1, and the slope is determined by looking up the table with the intermediate value F1 as the horizontal coordinate and the vehicle speed relative to the ground as the vertical coordinate. The larger F1 is and the smaller the vehicle speed is, the larger the slope obtained by looking up the table is. In the second mode, the slope θ is further calculated in combination with the intermediate value F1. The larger F1 is, the larger the calculated slope θ is.

[0128] The slope determination method of the above embodiment of the present application determines the slope by the first method, which has better robustness, is more practical and simple, and determines the slope by the second method, and the determined slope may be more accurate. Therefore, when the computing power of the corresponding controller is insufficient, the first method can be selected to determine the slope. When the computing power of the controller is sufficient, the two methods can be used together or one method can be selected based on the set rules. For example: the efficiency of determining the slope by looking up the table based on the intermediate value F1 is high, and the slope is further calculated based on the intermediate value F1, which may be more accurate, but requires more computing resources. Therefore, the accuracy of the slope can be determined based on the two methods. The corresponding weights are determined for the two methods, and the final slope is obtained by weighted fusion of the results of the two methods; or one of them can be set as the default method, and the default method is preferably selected to determine the slope. In this way, the method with the best comprehensive accuracy and efficiency can be determined from a variety of methods for determining the slope. At the same time, even if the vehicle's sensor is abnormal and the slope cannot be determined by collecting the longitudinal acceleration, the slope of the road where the vehicle is located can still be determined more accurately.

[0129] In a specific embodiment, the method currently selected to determine the slope may be determined based on the stability of the slope values ​​determined by different methods within a set time period. Correspondingly, the above-mentioned determination of the slope of the road on which the vehicle is located based on the first method and / or the second method includes:

[0130] Acquire multiple slopes determined based on the second method within a preset time before the current time; when the variance values ​​of the multiple slopes are less than a set variance threshold, select the second method to determine the slope; otherwise, select the first method to determine the slope.

[0131] The above embodiment combines the slope calculated by the dynamic table lookup with the slope estimated by the dynamic table to calculate the slope. Since the slope of the road surface generally does not change suddenly, and the slope determined by the second method is more accurate, the volatility of the slope determined by the second method can be considered, and the method for determining the current slope is selected based on this. For example, by calculating the variance value of multiple slopes determined based on method two over a period of time, if the variance value is less than the set threshold, it means that the multiple slopes determined based on method two have entered a steady state, and method two is preferred to determine the slope, otherwise the slope is determined by the F1 table lookup. Determining the method for determining the current slope by this method of historical data statistical verification is conducive to selecting the optimal method to determine the slope of the current road surface where the vehicle is located.

[0132] To better illustrate the technology of this application, please refer to Figure 5 , the vehicle braking control method of the present application will be described in conjunction with a detailed embodiment.

[0133] Step S501: The vehicle controller monitors the vehicle motor speed n, gear position, and longitudinal acceleration in real time. , vehicle mass m and the maximum available recovery torque of the motor.

[0134] Step S502: Calculate the vehicle speed based on the motor speed. The basic principle is as follows:

[0135]

[0136] Where V is the vehicle speed (unit: km / h), r is the tire radius (unit: meter), i is the speed ratio, is the conversion factor from rotation speed to vehicle speed.

[0137] Step S503: Determine the vehicle's driving direction based on the motor speed The basic principle is as follows:

[0138] The vehicle's driving direction is determined when any of the following conditions are met:

[0139] ① The vehicle speed is less than 5 km / h; (This threshold can be set to other values ​​based on actual needs, but generally the driving direction is determined when the absolute value of the vehicle speed over the ground is small);

[0140] ② The vehicle's driving direction changes;

[0141] In the embodiment of the present application, the vehicle driving direction is divided into forward and reverse. In some embodiments, the vehicle driving direction can be determined by the forward and reverse rotation of the motor. For example, a positive motor speed can correspond to a forward driving direction, and a negative motor speed can correspond to a reverse driving direction. For example, when the motor speed is less than -50rpm, it is determined that the driving direction is reverse, then Equal to -1, when the motor speed is greater than 50rpm, the driving direction is determined to be forward. Equal to 1. The thresholds -50rpm and 50rpm can be set to other values ​​according to actual conditions. In order to ensure the accuracy of the judgment, the threshold is generally not close to 0.

[0142] Step S504: Calculate the vehicle speed relative to the ground based on the driving direction and the motor speed, which is used to determine whether the vehicle is driving in the reverse direction. The basic principle is as follows:

[0143]

[0144] In the formula, is the vehicle speed over the ground (unit: km / h), is the vehicle's driving direction. As mentioned above, 1 and -1 can be used to represent the forward direction and the reverse direction respectively.

[0145] Step S505: Determine the activation flag of the electric brake function based on the target button, the accelerator, and the vehicle speed relative to the ground.

[0146] The target button may be a physical button or a virtual button inside the vehicle, and the association between the target button and the electric brake function is predefined. The target button may be a dedicated button for activating or deactivating the electric brake function, or may be a button that realizes other functions and is configured to activate or deactivate the electric brake function under specific operating conditions.

[0147] The activation conditions of the electric brake function include:

[0148] (1) A first condition that the duration of pressing a target control of the vehicle is greater than a preset duration threshold;

[0149] (2) A second condition that the number of key presses on the target control within a preset time period is greater than a preset key press threshold;

[0150] (3) The third condition that the relative distance between the vehicle and the preceding vehicle is less than a preset relative distance threshold and the relative speed is greater than a preset relative speed threshold;

[0151] When at least one of the first condition, the second condition, and the third condition is met, the electric braking function is activated. For example, if the driver often presses the target button for more than 1 second, it means that there is a need to decelerate.

[0152] The exit conditions of the electric brake function include: when the accelerator pedal opening is greater than a preset ratio or the vehicle speed to the ground is less than a preset reverse speed, the electric brake function is exited. For example, the driver's accelerator pedal opening is greater than 20%; or the vehicle speed to the ground is less than -5km / h. When the driver pedals with a large amplitude, it means that there is a need for acceleration. When the vehicle speed to the ground is less than -5km / h, it means that the vehicle has reversed. In order to avoid unexpected movement, the electric brake function is forced to exit.

[0153] Step S506: Calculate the slope based on the vehicle speed over the ground, wheel end torque, etc. The basic principle is as follows:

[0154] F1 ,

[0155] ,

[0156] in, Wheel end torque (unit: Nm), r is the tire radius of the vehicle (unit: m), is the air resistance coefficient, is the frontal area of ​​the vehicle (unit: square meters), is a constant of 1.2258, is the rotation mass conversion factor, is the vehicle speed relative to the ground (unit: km / h), m is the vehicle weight (unit: kilograms), g is the gravity coefficient, f is the rolling resistance coefficient, F1 is the intermediate value, and θ represents the calculated slope (unit: degree).

[0157] The slope calculation method can be combined with F1 table lookup and / or calculated based on F1. When using F1 to look up the table, the slope is calculated by looking up the table with F1 as the horizontal coordinate and the ground speed as the vertical coordinate. The larger the F1 and the smaller the ground speed, the greater the slope. The weight can also be selected based on the actual accuracy of the two methods, and the final slope is calculated based on the results of the two methods based on the weight fusion. One of the weight calculation methods is: by calculating the variance value of multiple θ within a period of time, if the variance value is less than the set threshold, it means that the calculated θ value has entered a steady state, and the calculated θ is preferentially selected as the slope, otherwise the F1 table lookup is preferentially selected to determine the slope.

[0158] Among them, the way of preferentially selecting θ may include: assigning a larger weight to θ and assigning a smaller weight to the slope determined by F1; or directly selecting θ as the final slope. Similarly, the way of preferentially selecting the F1 table lookup value may include: assigning a larger weight to the slope determined by F1 and assigning a larger weight to θ; or directly selecting the slope determined by F1 as the final slope.

[0159] Step S507: Calculate the electric brake initial torque based on the slope and determine the target deceleration.

[0160] As an example, by looking up the table below with the slope as the horizontal axis, the electric braking initial torque can be obtained. The setting principle of the electric braking initial torque is to overcome the slope component of the road surface on which the vehicle is located. The greater the current slope, the greater the electric braking initial torque.

[0161] Slope (unit: degrees) -5 0 5 Electric brake initial torque (unit: Nm) -500 0 500

[0162] Among them, a positive slope value indicates an uphill slope, and a negative slope value indicates a downhill slope.

[0163] When the activation flag of the electric brake function indicates that the electric brake function is activated, the target deceleration can be determined in the following way: when the vehicle's ground speed is positive and greater than the set threshold, the ground speed is used as the horizontal coordinate and the slope is used as the vertical coordinate, and the target deceleration of the electric brake is calculated by looking up the table. The greater the ground speed and the greater the slope, the greater the target deceleration should be, so that the vehicle can decelerate in time; conversely, the smaller the ground speed and the smaller the slope, the smaller the target deceleration should be, so that the vehicle can decelerate more smoothly.

[0164] Step S508: Determine the electric braking target torque based on the activation flag of the electric braking function, the vehicle speed over the ground, the slope, the electric braking initial torque, the target deceleration, the maximum recovery torque available for the motor, and the PID control.

[0165] When the electric brake function is activated, PID control can be performed in two stages based on the vehicle speed relative to the ground.

[0166] Phase 1: When the ground speed is positive and greater than the set threshold, the ground speed is used as the horizontal coordinate and the slope is used as the vertical coordinate, and the target deceleration of the electric brake is calculated by looking up the table. At the same time, the actual speed change rate (i.e., the actual deceleration) is calculated by taking the derivative of the ground speed. The PID closed-loop control input is determined by calculating the difference between the target deceleration and the actual speed change rate and the difference change rate. The PI item is determined by looking up the table with the difference as the horizontal coordinate, and the D item is determined by looking up the table with the difference change rate. The smoothness of the vehicle is ensured by setting the target deceleration.

[0167] Phase 2: When the ground speed is less than the above-mentioned threshold and close to zero speed, the target of the closed-loop control of the target deceleration is switched to zero, that is, the target deceleration is reset to 0, and the difference between the target deceleration and the actual speed change rate and the difference change rate are calculated as the PID control input. At the same time, the target speed is set to zero, and the difference between the target speed and the actual speed and the difference change rate are calculated as another PID control input, that is, the vehicle must be stationary. The vehicle is stationary by two factors: the speed is 0 and the target deceleration is 0. Among them, the target speed and the actual speed both refer to the ground speed.

[0168] Finally, the motor braking target torque in the above-mentioned phase 1 and phase 2 is equal to the torque adjusted by the superposition of the electric braking initial torque and the PID closed-loop control. At the same time, in the embodiment of the present application, all electric braking torques must be within the maximum recovery torque range available for the motor.

[0169] In the above embodiment, whether to activate the electric brake function can be determined based on the conditions of the button, throttle, and vehicle speed relative to the ground. When the electric brake function is activated, in the first stage when the vehicle speed relative to the ground is positive and greater than the set threshold, the motor torque is closed-loop controlled based on the target deceleration, so that the vehicle decelerates smoothly according to the target deceleration. In the second stage when the vehicle speed relative to the ground is less than the above-set threshold and close to zero, the target deceleration is reset to 0, and the motor torque is controlled by PID with the new target deceleration as the target. At the same time, the target vehicle speed is set to zero, and the motor torque is controlled by another PID with the target vehicle speed as the target, that is, in this stage, the vehicle is stationary by the two factors of the vehicle speed being 0 and the target deceleration being 0. By controlling the motor torque in this way, accurate braking capacity can be provided to the vehicle after the braking system fails, thereby improving the driving safety of the vehicle.

[0170] It should be understood that, although the steps in the flowcharts involved in the above embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0171] Based on the same inventive concept, the embodiment of the present application also provides a vehicle brake control device for implementing the vehicle brake control method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more vehicle brake control device embodiments provided below can refer to the limitations of the vehicle brake control method above, and will not be repeated here.

[0172] In an exemplary embodiment, Figure 6 As shown, a vehicle braking control device is provided, comprising:

[0173] The first adjustment module 601 is used to determine a target deceleration when the electric brake function of the vehicle is activated; based on the target deceleration, adjust the motor output torque through the first PID control so that the vehicle gradually decelerates with the aforementioned target deceleration as the target;

[0174] The second adjustment module 602 is used to update the aforementioned target deceleration to zero when the vehicle decelerates to a preset vehicle speed threshold, and based on the updated target deceleration, continue to adjust the motor output torque through the aforementioned first PID control, and set the target vehicle speed to zero, and based on the target vehicle speed, adjust the motor output torque through the second PID control to control vehicle braking.

[0175] Based on the vehicle brake control device of the above embodiment, when the electric brake function of the vehicle is activated, the first adjustment module takes the target deceleration as the target, and adjusts the motor output torque through the first PID control to make the vehicle decelerate smoothly. Then, when the vehicle decelerates to a preset vehicle speed threshold, the second adjustment module updates the target deceleration to zero, and continues to adjust the motor output torque through the first PID control based on the updated target deceleration. At the same time, the target vehicle speed is also set to zero, and the motor output torque is adjusted through the second PID control based on the target vehicle speed, that is, when the vehicle speed is close to 0, the motor output torque is controlled and adjusted by the target deceleration and the target vehicle speed at the same time to ensure that the vehicle stops. The entire electric braking process not only achieves smooth deceleration, but also ensures safety during parking.

[0176] In one embodiment, the first adjustment module 601 may be specifically used for:

[0177] Obtain the actual speed change rate of the vehicle; obtain a first difference between the target deceleration and the aforementioned actual speed change rate, and a first difference change rate of the first difference; based on the aforementioned first difference and the aforementioned first difference change rate, determine the input of the first PID control to adjust the motor output torque through the first PID control; wherein the inputs of the P item and the I item are determined based on the first difference, and the input of the D item is determined based on the first difference change rate.

[0178] In one embodiment, the second adjustment module 602 may be specifically configured to:

[0179] Acquire the actual ground speed of the vehicle; determine a second difference between the target speed and the actual ground speed, and a second difference change rate of the second difference; determine an input of a second PID control based on the second difference and the second difference change rate to adjust the motor output torque to control vehicle braking; wherein the inputs of item P and item I are determined based on the second difference, and the input of item D is determined based on the second difference change rate.

[0180] In one embodiment, the vehicle braking control device further includes a vehicle speed change rate acquisition module, which is used to:

[0181] The vehicle speed is determined based on the motor speed of the vehicle; the vehicle speed relative to the ground is determined based on the vehicle's driving direction and the aforementioned vehicle speed; the aforementioned driving direction is forward or reverse; the actual vehicle speed change rate of the vehicle is obtained by differentiating the vehicle speed relative to the ground.

[0182] In one embodiment, the vehicle braking control device further includes a driving direction determination module, which is used to:

[0183] The driving direction of the vehicle is determined based on the wheel speed direction when any of the following conditions is met: (1) the vehicle speed is less than a preset forward speed; (2) the vehicle's driving direction changes.

[0184] In one embodiment, when the electric brake function of the vehicle is activated, the first adjustment module 601 determines the target deceleration in the following manner:

[0185] When the electric brake function of the vehicle is activated, the target deceleration is determined based on the vehicle's current ground speed, the slope of the road surface and a preset mapping table.

[0186] In one embodiment, the vehicle brake control device further includes a slope determination module, which is used to:

[0187] Based on the first method and / or the second method, the slope of the road on which the vehicle is located is determined; in the first method, an intermediate value is determined based on the vehicle speed relative to the ground, the wheel-end torque and the tire radius, and the slope is determined by looking up the table based on the intermediate value; in the second method, an intermediate value is determined based on the vehicle speed relative to the ground, the wheel-end torque and the tire radius, and the intermediate value is substituted into a preset calculation model to determine the slope.

[0188] In one embodiment, the slope determination module may be specifically configured to:

[0189] Acquire multiple slopes determined based on the aforementioned second method within a preset time before the current time; when the variance value of the multiple slopes is less than the set variance threshold, select the aforementioned second method to determine the slope; otherwise, select the aforementioned first method to determine the slope.

[0190] In one embodiment, the vehicle brake control device further includes an electric brake function management module, which is used to:

[0191] The aforementioned electric braking function is activated when at least one of the following conditions is met;

[0192] A first condition that the pressing time of the target button of the aforementioned vehicle is greater than a preset time threshold;

[0193] A second condition that the number of key presses on the aforementioned target key within a preset time period is greater than a preset key press number threshold;

[0194] The third condition is that the relative distance between the aforementioned vehicle and the preceding vehicle is less than a preset relative distance threshold, and the relative speed is greater than a preset relative speed threshold.

[0195] In one embodiment, the electric brake function management module is further used to exit the electric brake function when the accelerator pedal opening is greater than a preset proportional value or the vehicle speed relative to the ground is less than a preset reverse speed.

[0196] Each module in the above vehicle brake control device can be implemented in whole or in part by software, hardware or a combination thereof. Each module can be embedded in or independent of the processor in the new energy vehicle in the form of hardware, or can be stored in the memory in the new energy vehicle in the form of software, so that the processor can call and execute the corresponding operations of each module.

[0197] In an exemplary embodiment, a new energy vehicle is provided, and its internal structure diagram can be as follows: Figure 7 As shown. The new energy vehicle includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. Among them, the processor of the new energy vehicle is used to provide computing and control capabilities. The memory of the new energy vehicle includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the new energy vehicle is used to exchange information between the processor and the external device. The communication interface of the new energy vehicle is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be realized through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a vehicle braking control method is realized. The display unit of the new energy vehicle is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the new energy vehicle can be a touch layer covered on the display screen, or it can be a button, trackball or touchpad set in the new energy vehicle.

[0198] Those skilled in the art will understand that Figure 7 The structure shown in the figure is only a block diagram of a part of the structure related to the scheme of the present application, and does not constitute a limitation on the new energy vehicle to which the scheme of the present application is applied. A specific new energy vehicle may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0199] In an exemplary embodiment, a new energy vehicle is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps in the above-mentioned vehicle braking control method embodiments when executing the computer program.

[0200] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0201] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0202] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0203] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0204] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A vehicle braking control method, characterized in that: include: determining a target deceleration with an electric brake function of the vehicle activated; Based on the target deceleration, adjusting the motor output torque through a first proportional integral differential (PID) control so that the vehicle gradually decelerates with the target deceleration as the target; When the vehicle decelerates to a preset vehicle speed threshold, the target deceleration is updated to zero, and based on the updated target deceleration, the motor output torque is continued to be adjusted through the first PID control, and the target vehicle speed is set to zero. Based on the target vehicle speed, the motor output torque is adjusted through the second PID control to control vehicle braking.

2. The method according to claim 1, characterized in that The adjusting the motor output torque by a first PID control based on the target deceleration includes: Obtaining an actual speed change rate of the vehicle; Acquire a first difference between the target deceleration and the actual vehicle speed change rate, and a first difference change rate of the first difference; Based on the first difference and the first difference change rate, the input of the first PID control is determined to adjust the motor output torque through the first PID control; wherein the inputs of the P item and the I item are determined based on the first difference, and the input of the D item is determined based on the first difference change rate.

3. The method according to claim 1, characterized in that The adjusting the motor output torque by the second PID control based on the target vehicle speed includes: Obtaining the actual ground speed of the vehicle; determining a second difference between the target vehicle speed and the actual vehicle speed over the ground, and a second difference change rate of the second difference; The input of the second PID control is determined based on the second difference and the second difference change rate to adjust the motor output torque to control vehicle braking; wherein the inputs of the P item and the I item are determined based on the second difference, and the input of the D item is determined based on the second difference change rate.

4. The method according to claim 2, characterized in that: The obtaining of the actual speed change rate of the vehicle includes: Determining a vehicle speed based on a motor speed of the vehicle; Determining the vehicle's ground speed based on the vehicle's traveling direction and the vehicle speed; the traveling direction is forward or reverse; The actual vehicle speed change rate of the vehicle is obtained by derivatizing the vehicle speed relative to the ground.

5. The method according to claim 4, characterized in that Also includes: When any of the following conditions is met, the driving direction of the vehicle is determined based on the wheel speed direction: The vehicle speed is less than the preset forward speed; The driving direction of the vehicle changes.

6. The method according to claim 1, characterized in that The step of determining the target deceleration when the electric brake function of the vehicle is activated includes: When the electric brake function of the vehicle is activated, the target deceleration is determined by looking up the table based on the current vehicle speed relative to the ground, the slope of the road surface and a preset mapping table.

7. The method according to claim 6, characterized in that Also includes: Determine the slope of the road on which the vehicle is located based on the first method and / or the second method; In the first mode, an intermediate value is determined based on the vehicle speed relative to the ground, the wheel end torque and the tire radius, and the slope is determined by looking up a table based on the intermediate value; In the second mode, an intermediate value is determined based on the vehicle speed relative to the ground, the wheel end torque and the tire radius, and the intermediate value is substituted into a preset calculation model to determine the slope.

8. The method according to claim 7, characterized in that The determining the slope of the road on which the vehicle is located based on the first method and / or the second method includes: Acquire multiple slopes determined based on the second method within a preset time before the current time; When the variance values ​​of the multiple slopes are smaller than the set variance threshold, the second method is selected to determine the slope; otherwise, the first method is selected to determine the slope.

9. The method according to any one of claims 1 to 8, characterized in that: Also includes: Activating the electric braking function when at least one of the following conditions is met: A first condition that a key press duration of a target key of the vehicle is greater than a preset duration threshold; A second condition that the number of key presses on the target key within a preset time period is greater than a preset key press number threshold; The third condition is that the relative distance between the vehicle and the preceding vehicle is less than a preset relative distance threshold, and the relative speed is greater than a preset relative speed threshold.

10. The method according to claim 9, characterized in that Also includes: When the accelerator pedal opening is greater than a preset proportional value or the vehicle speed relative to the ground is less than a preset reverse vehicle speed, the electric braking function is exited.

11. A vehicle brake control device, characterized in that: include: a first regulating module, for determining a target deceleration when an electric braking function of the vehicle is activated; Based on the target deceleration, adjusting the motor output torque through a first PID control so that the vehicle gradually decelerates with the target deceleration as a target; The second regulating module is used to update the target deceleration to zero when the vehicle decelerates to a preset vehicle speed threshold, and based on the updated target deceleration, continue to adjust the motor output torque through the first PID control, and set the target vehicle speed to zero, and based on the target vehicle speed, adjust the motor output torque through the second PID control to control vehicle braking.

12. A new energy vehicle, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 10 are implemented.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 10 are implemented.

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