Brake control method and system for automatic driving flat car and computer equipment

文档序号：478907 发布日期：2022-01-04 浏览：36次中文

阅读说明：本技术 自动驾驶平板车的制动控制方法、系统和计算机设备 (Brake control method and system for automatic driving flat car and computer equipment ) 是由王阳王泽坤王凯赵彬郝值刘新宇于 2021-11-04 设计创作，主要内容包括：本申请涉及一种自动驾驶平板车的制动控制方法、系统、计算机设备和存储介质,方法包括：若控制指令解析为制动请求时,则获取制动请求的目标减速度,控制指令用于指示外部控制器根据整车的需求而发送的控制指令；根据目标减速度,判断整车的制动强度；根据制动强度,确定整车的制动方式；根据制动方式,对整车进行制动。相较于相关技术中在对整车进行制动时,只考虑制动能量的回收率,由于可以根据目标减速对整车的制动强度进行分级,从而选择对应的制动方式实现对整车的制动,进而可以实现在安全制动的条件下,实现制动能量的回收,即提高了整车的安全性,又提高了制动能量的回收率。(The application relates to a brake control method, a brake control system, computer equipment and a storage medium of an automatic driving flat car, wherein the method comprises the following steps: if the control instruction is analyzed to be a braking request, acquiring a target deceleration of the braking request, wherein the control instruction is used for indicating a control instruction sent by an external controller according to the requirement of the whole vehicle; judging the braking strength of the whole vehicle according to the target deceleration; determining the braking mode of the whole vehicle according to the braking strength; and braking the whole vehicle according to the braking mode. Compared with the prior art that only the recovery rate of the braking energy is considered when the whole vehicle is braked, the braking intensity of the whole vehicle can be graded according to the target deceleration, so that the corresponding braking mode is selected to realize the braking of the whole vehicle, and the recovery of the braking energy can be realized under the condition of safe braking, thereby improving the safety of the whole vehicle and the recovery rate of the braking energy.)

1. A brake control method of an autonomous flatbed, comprising:

if the control instruction is analyzed to be a braking request, acquiring the target deceleration of the braking request, wherein the control instruction is used for instructing an external controller to send a control instruction according to the requirement of the whole vehicle;

judging the braking strength of the whole vehicle according to the target deceleration;

determining the braking mode of the whole vehicle according to the braking intensity;

and braking the whole vehicle according to the braking mode.

2. The method of claim 1, wherein the step of sending the control command according to the requirement of the whole vehicle comprises:

acquiring a starting instruction;

according to the starting instruction, boosting a main loop of a brake control system to enable the brake control system to enter a preparation state, wherein the preparation state is used for indicating a motor in the brake control system to enable liquid oil in an oil tank to enter the main loop through a hydraulic pump, so that the pressure of the main loop is increased, and the whole vehicle enters the preparation state;

and if the pressure of the main loop rises to a preset pressure threshold value, the whole vehicle enters a running state, and the control instruction is obtained.

3. The method of claim 1, wherein the brake intensity includes emergency braking, moderate braking, and light braking; correspondingly, the judging the braking strength of the whole vehicle according to the target deceleration comprises the following steps:

if the target deceleration is greater than a first preset deceleration threshold, the braking strength of the whole vehicle is emergency braking;

if the target deceleration is smaller than a first preset deceleration threshold and larger than a second preset deceleration threshold, the braking strength of the whole vehicle is moderate braking;

and if the target deceleration is smaller than a second preset deceleration threshold, the braking strength of the whole vehicle is light braking.

4. The method according to claim 1, wherein determining the braking mode of the entire vehicle based on the braking intensity comprises determining a total braking torque of the entire vehicle based on the target deceleration.

5. The method of claim 1, wherein the braking modes include hydraulic braking, electro-hydraulic hybrid braking, and electric braking; correspondingly, according to the brake intensity, determining the brake mode of the whole vehicle comprises the following steps:

if the braking strength of the whole vehicle is emergency braking, determining that the braking mode of the whole vehicle is hydraulic braking;

if the braking strength of the whole vehicle is moderate braking, determining that the braking mode of the whole vehicle is electro-hydraulic hybrid braking;

and if the braking strength of the whole vehicle is mild braking, determining that the braking mode of the whole vehicle is electric braking.

6. The method of claim 5, wherein the electro-hydraulic hybrid braking includes electric braking and hydraulic braking; correspondingly, after determining that the braking mode of the whole vehicle is electro-hydraulic hybrid braking, the method comprises the following steps:

acquiring the residual capacity of a storage battery of the whole vehicle;

and determining the braking proportion of electric braking and hydraulic braking in the electro-hydraulic hybrid braking according to the residual capacity of the storage battery.

7. The method of claim 1, wherein braking the entire vehicle according to the braking mode comprises:

if the braking mode is hydraulic braking, the whole vehicle is braked by adopting hydraulic braking according to the total braking torque;

and if the braking mode is electric braking, the whole vehicle is braked by adopting electric braking according to the total braking torque.

8. The method of claim 1, wherein if the braking mode is electro-hydraulic hybrid braking; correspondingly, according to the braking mode, to whole car brakies, include:

determining the braking torque of the electric braking and the braking torque of the hydraulic braking in the electro-hydraulic hybrid braking according to the braking proportion of the electric braking and the hydraulic braking in the electro-hydraulic hybrid braking and the total braking torque;

and according to the braking torque of the electric braking and the braking torque of the hydraulic braking in the electro-hydraulic hybrid braking, the whole vehicle is braked by adopting the hydraulic hybrid braking.

9. A brake control system for an autonomous-capable flatbed, said system comprising:

the external controller is used for sending a control command according to the requirement of the whole vehicle and receiving the braking torque sent to the braking control system by the braking controller and the feedback state of the braking control system;

the brake controller is used for controlling the whole vehicle according to the control instruction;

the wheel cylinder pressure sensor is used for monitoring the wheel cylinder pressure of the whole vehicle, and when the pressure is insufficient or overhigh, the pressure state is fed back to the external controller through the brake controller;

the main loop pressure sensor is used for monitoring the main loop pressure of the brake control system and returning a monitoring value to the brake controller, and when the main loop pressure is insufficient or too high, the brake controller feeds the pressure state back to the external controller;

an accumulator for storing energy to ensure that the pressure of the main circuit is maintained at a normal level;

the motor is used for providing power for the hydraulic pump;

a hydraulic pump for building pressure to a main circuit of the brake control system;

the manual pump is used for building pressure on a main circuit of the brake control system in a manual pump mode when the hydraulic pump fails;

the overflow valve is used for controlling the pressure of the main loop of the brake control system to be maintained at the preset pressure threshold value, and when the pressure of the main loop of the brake control system exceeds the preset pressure threshold value, the overflow valve unloads the pressure and returns the pressure to the oil tank;

the oil tank is used for storing hydraulic oil, and the energy is 0;

the wheel cylinder is used for controlling the running or braking of the whole vehicle according to the hydraulic pressure in the wheel cylinder;

the brake pressure reducing valve is used for controlling the hydraulic pressure of the wheel cylinder to realize the closed-loop control of the brake torque and the brake pressure of the hydraulic brake;

the deceleration sensor is used for detecting the actual deceleration of the vehicle and returning the actual deceleration to the brake controller to realize the closed-loop control of the deceleration of the whole vehicle;

the storage battery is used for providing a power supply for the whole vehicle, and when the whole vehicle adopts electric braking, energy recovery can be carried out.

10. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor, when executing the computer program, implements the steps of the method of any of claims 1 to 7.

11. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 7.

Technical Field

The application relates to the technical field of automatic driving, in particular to a brake control method and system for an automatic driving flat car and computer equipment.

Background

With the development of the automatic driving technology, the brake control of the automatic driving flat car is continuously improved, the brake control of the automatic driving flat car is generally realized by adopting hydraulic brake or electric brake, and a large part of kinetic energy is wasted in the process of realizing the brake of the automatic driving flat car. In the related technology, the braking energy can be recovered, when the automatic driving flat car decelerates or brakes, the motor reversely rotates to provide braking torque, so that the motor runs in the form of a generator, mechanical energy can be converted into electric energy to charge the storage battery, and the purpose of recovering the braking energy is achieved. However, if the recovery rate of the braking energy is considered only when the autonomous flatbed vehicle is in an emergency, particularly when the autonomous flatbed vehicle is driven with a heavy load, a safety hazard may be caused. Therefore, a braking control method for an autonomous flatbed is urgently needed.

Disclosure of Invention

In view of the above, it is necessary to provide a brake control method, system, computer device and storage medium for an autonomous flatbed.

A brake control method of an autonomous flatbed, the method comprising:

if the control instruction is analyzed to be a braking request, acquiring a target deceleration of the braking request, wherein the control instruction is used for indicating a control instruction sent by an external controller according to the requirement of the whole vehicle;

judging the braking strength of the whole vehicle according to the target deceleration;

determining the braking mode of the whole vehicle according to the braking strength;

and braking the whole vehicle according to the braking mode.

In one embodiment, before the control instruction sent according to the requirement of the entire vehicle, the method includes:

acquiring a starting instruction;

according to a starting instruction, boosting a main loop of a brake control system to enable the brake control system to enter a preparation state, wherein the preparation state is used for indicating a motor in the brake control system to enable liquid oil in an oil tank to enter the main loop through a hydraulic pump, so that the pressure of the main loop is increased, and a whole vehicle enters the preparation state;

and if the pressure of the main loop rises to a preset pressure threshold value, the whole vehicle enters a running state, and a control instruction is obtained.

In one embodiment, the braking intensity includes emergency braking, moderate braking and light braking; correspondingly, according to the target deceleration, the method for judging the braking strength of the whole vehicle comprises the following steps:

if the target deceleration is greater than the first preset deceleration threshold, the braking strength of the whole vehicle is emergency braking;

if the target deceleration is smaller than the first preset deceleration threshold and larger than the second preset deceleration threshold, the braking strength of the whole vehicle is moderate braking;

and if the target deceleration is smaller than a second preset deceleration threshold, the braking intensity of the whole vehicle is light braking.

In one embodiment, before determining the braking mode of the whole vehicle according to the braking intensity, the total braking torque of the whole vehicle is determined according to the target deceleration.

In one embodiment, the braking modes comprise hydraulic braking, electro-hydraulic hybrid braking and electric braking; correspondingly, according to the brake intensity, the brake mode of the whole vehicle is determined, and the method comprises the following steps:

if the braking strength of the whole vehicle is emergency braking, determining that the braking mode of the whole vehicle is hydraulic braking;

if the braking strength of the whole vehicle is moderate braking, determining that the braking mode of the whole vehicle is electro-hydraulic hybrid braking;

and if the braking strength of the whole vehicle is mild braking, determining that the braking mode of the whole vehicle is electric braking.

In one embodiment, the electro-hydraulic hybrid braking comprises electric braking and hydraulic braking; correspondingly, after the braking mode of the whole vehicle is determined to be electro-hydraulic hybrid braking, the method comprises the following steps:

acquiring the residual capacity of a storage battery of the whole vehicle;

and determining the braking proportion of electric braking and hydraulic braking in the electro-hydraulic hybrid braking according to the residual capacity of the storage battery.

In one embodiment, braking the entire vehicle according to a braking mode comprises:

if the braking mode is hydraulic braking, the whole vehicle is braked by adopting hydraulic braking according to the total braking torque;

and if the braking mode is electric braking, the whole vehicle is braked by adopting electric braking according to the total braking torque.

In one embodiment, if the braking mode is electro-hydraulic hybrid braking; correspondingly, according to the braking mode, the whole vehicle is braked, and the method comprises the following steps:

determining the braking torque of electric braking and the braking torque of hydraulic braking in the electro-hydraulic hybrid braking according to the braking proportion and the total braking torque of the electric braking and the hydraulic braking in the electro-hydraulic hybrid braking;

and according to the braking torque of the electric brake and the braking torque of the hydraulic brake in the electro-hydraulic hybrid brake, the whole vehicle is braked by adopting the hydraulic hybrid brake.

A brake control system for an autonomous flatbed, the system comprising:

the brake controller is used for controlling the whole vehicle according to the control instruction;

the energy accumulator is used for storing energy and ensuring that the pressure of the main circuit is maintained at a normal level;

the motor is used for providing power for the hydraulic pump;

a hydraulic pump for building pressure to a main circuit of the brake control system;

the manual pump is used for building pressure on a main loop of the brake control system in a manual pump mode when the hydraulic pump fails;

the overflow valve is used for controlling the pressure of a main loop of the brake control system to be maintained at a preset pressure threshold value, and unloading the pressure to the oil tank when the pressure of the main loop of the brake control system exceeds the preset pressure threshold value;

the oil tank is used for storing hydraulic oil, and the energy is 0;

the wheel cylinder is used for controlling the running or braking of the whole vehicle according to the pressure of hydraulic pressure in the wheel cylinder;

the deceleration sensor is used for detecting the actual deceleration of the whole vehicle and returning the actual deceleration to the brake controller to realize the closed-loop control of the deceleration of the whole vehicle;

and the storage battery is used for providing a power supply for the whole vehicle, and can recover energy when the whole vehicle adopts electric braking. A computer device comprising a memory and a processor, the memory storing a computer program, the processor implementing the following steps when executing the computer program:

judging the braking strength of the whole vehicle according to the target deceleration;

determining the braking mode of the whole vehicle according to the braking strength;

and braking the whole vehicle according to the braking mode.

A computer-readable storage medium, on which a computer program is stored which, when executed by a processor, carries out the steps of:

judging the braking strength of the whole vehicle according to the target deceleration;

determining the braking mode of the whole vehicle according to the braking strength;

and braking the whole vehicle according to the braking mode.

According to the brake control method, the brake control system, the computer equipment and the storage medium of the automatic driving flat car, if the control instruction is analyzed to be the brake request, the target deceleration of the brake request is obtained, and the control instruction is used for instructing an external controller to send the control instruction according to the requirement of the whole car; judging the braking strength of the whole vehicle according to the target deceleration; determining the braking mode of the whole vehicle according to the braking strength; and braking the whole vehicle according to the braking mode. Compared with the prior art that only the recovery rate of the braking energy is considered when the whole vehicle is braked, the braking intensity of the whole vehicle can be graded according to the target deceleration, so that the corresponding braking mode is selected to realize the braking of the whole vehicle, and the recovery of the braking energy can be realized under the condition of safe braking, thereby improving the safety of the whole vehicle and the recovery rate of the braking energy.

Drawings

FIG. 1 is a diagram illustrating an exemplary application of a braking method for an autonomous flatbed;

FIG. 2 is a schematic flow chart illustrating a braking method for an autonomous flatbed in one embodiment;

FIG. 3 is a block diagram of a brake system of an autonomous flat vehicle according to an embodiment;

FIG. 4 is a schematic diagram illustrating a state transition of the brake control system in one embodiment;

FIG. 5 is a schematic illustration of a braking energy recovery control strategy in one embodiment;

FIG. 6 is a diagram illustrating an internal structure of a computer device according to an embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

The braking control method of the automatic driving flat car can be applied to the application environment shown in fig. 1. The camera 101 communicates with the server 102 via a network. The camera 101 is generally disposed at a front end of the whole vehicle, the camera can acquire a road condition in a driving direction of the whole vehicle in real time and transmit the road condition to the server 102, the server 102 can analyze the real-time road condition to obtain an analysis result, and control of the whole vehicle is achieved according to the obtained analysis result.

In addition, the processing device for analyzing and processing the road condition is not necessarily a server, and may also be a special processing device, such as a personal computer or a notebook computer, and even if the portable wearable device is capable of linking with the camera 101, the processing device may also be a portable wearable device, which is not limited in this embodiment of the present invention. It should be noted that, the numbers of "a plurality" and the like mentioned in the embodiments of the present application each refer to a number of "at least two", for example, "a plurality" refers to "at least two".

What process the server 102 specifically handles is related to the specific use corresponding to the application scenario in fig. 1. The method has the specific purpose of analyzing the current running condition of the whole vehicle, and if an obstacle appears on the running road of the whole vehicle, the whole vehicle can be safely braked according to the obstacle and the safe distance, so that the safety performance of automatic driving is improved.

As can be seen from the above description, the application scenario in fig. 1 may be specifically applied to implement brake control for an autonomous flatbed under safe conditions, and improve energy recovery rate. Based on this, referring to fig. 2, a brake control method of the autonomous flatbed is provided. The method is applied to a server, and an execution subject is taken as an example for explanation, and the method comprises the following steps:

201. if the control instruction is analyzed to be a braking request, acquiring a target deceleration of the braking request, wherein the control instruction is used for indicating a control instruction sent by an external controller according to the requirement of the whole vehicle;

202. judging the braking strength of the whole vehicle according to the target deceleration;

203. determining the braking mode of the whole vehicle according to the braking strength;

204. and braking the whole vehicle according to the braking mode.

In step 201, the control command refers to a control command sent to the brake controller by the external controller after performing analysis processing according to specific requirements of the entire vehicle and making a judgment. The brake controller is used for not only realizing brake control of the whole vehicle, but also performing other controls such as brake energy recovery, whole vehicle running, whole vehicle deceleration and parking, parking brake release and the like according to control instructions sent by an external controller. Specifically, the specific content of the control command may include a driving request, a parking request, a braking request, a parking brake releasing request, and the like.

The target deceleration refers to the minimum deceleration required by the external controller to perform safe braking on the whole vehicle according to the acquired safe distance, namely, when the whole vehicle brakes, if the braking is required to be completed within the safe distance, the deceleration cannot be smaller than the minimum deceleration.

In the step 202, the braking intensity refers to an emergency degree of braking of the whole vehicle, which can reflect the braking capability of the whole vehicle,

in the step 203, the braking mode refers to a mode adopted when the whole vehicle is braked, specifically, the selection of the braking mode is related to the braking intensity, and the braking intensity is determined by the target deceleration, that is, the selection of the braking mode is also related to the target deceleration.

Specifically, when the brake controller receives a control instruction sent by the external controller and analyzes that the content of the control instruction is that the whole vehicle needs to be braked, the target deceleration of the whole vehicle needs to be obtained from the external controller, then the brake controller can judge the current braking strength of the whole vehicle according to the target deceleration, and after the braking strength of the whole vehicle is determined, the brake controller can further determine the braking mode which needs to be adopted by the current whole vehicle, so that the brake control of the whole vehicle is realized, and the whole vehicle can be braked within a safe distance.

The method provided by the embodiment of the invention can judge the current emergency situation of the whole vehicle braking by determining the target deceleration of the whole vehicle, thereby selecting different braking modes, further improving the safety of the whole vehicle during the braking and improving the recovery rate of the braking energy when the whole vehicle is braked.

In one embodiment, before the control instruction sent according to the requirement of the entire vehicle, the method includes:

301. acquiring a starting instruction;

302. according to a starting instruction, boosting a main loop of a brake control system to enable the brake control system to enter a preparation state, wherein the preparation state is used for indicating a motor in the brake control system to enable liquid oil in an oil tank to enter the main loop through a hydraulic pump, so that the pressure of the main loop is increased, and a whole vehicle enters the preparation state;

303. and if the pressure of the main loop rises to a preset pressure threshold value, the whole vehicle enters a running state and acquires a control instruction.

In step 301, the start command is an instruction for starting the operation of the brake control system, and when the external controller obtains the ignition action of the entire vehicle, the external controller sends the start command to the brake controller. When the external controller does not acquire the ignition action of the whole vehicle, the brake control system is in an initialization state at the moment, and the brake control system does not have any activity at the moment.

In step 302, the ready state refers to a process of boosting the main circuit of the brake control system. When the brake controller receives a starting instruction, the motor is controlled to work, the motor provides power for the hydraulic pump, the hydraulic pump conveys liquid oil in the oil tank to the brake control system, the energy accumulator starts to accumulate energy at the moment, and the pressure sensor continuously collects pressure in the main loop and transmits the pressure to the brake controller, so that the brake controller can constantly monitor the pressure of the main loop in the brake control system, and closed-loop control of the brake controller on the pressure of the main loop in the brake control system is realized, for example, the brake controller can adopt a PID control algorithm to realize closed-loop control on the pressure of the main loop.

In step 303, when the pressure of the main circuit rises to the preset pressure threshold, the entire vehicle enters the running state. When the whole vehicle enters the running state, if the brake controller analyzes the control command to be the request for releasing the parking brake, the brake controller controls the brake pressure reducing valve to fill liquid oil in the wheel cylinders of all wheels, so that the parking brake of the whole vehicle is released, and at the moment, the whole vehicle can run.

In addition, if the pressure of the main circuit does not rise to the preset pressure threshold value, the whole vehicle has flameout action, so that the whole vehicle can directly enter a stop state from a preparation state, after the whole vehicle enters the stop state, the brake control system can unload the wheel cylinders of all wheels through the brake pressure reducing valve, and meanwhile, the main circuit of the brake control system can also unload, so that the pressures of the main circuit and the wheel cylinders of all wheels are reduced to 0.

In addition, after the pressure unloading of the brake control system is finished, the state of the whole vehicle enters an end state from a stop state, when the whole vehicle enters the end state, the whole vehicle finishes all instructions of the time, and then the whole vehicle is switched to a preparation state to wait for the next work of the brake control system.

According to the method provided by the embodiment of the invention, the pressure of the main loop of the brake control system is transmitted to the brake controller in real time through the pressure sensor, so that the brake controller can master the state of the brake control system in real time, the brake controller can realize real-time control on the brake control system, and the control efficiency of the whole vehicle is further improved.

In one embodiment, the brake intensity includes emergency braking, moderate braking, and light braking; correspondingly, according to the target deceleration, the method for judging the braking strength of the whole vehicle comprises the following steps:

401. if the target deceleration is greater than the first preset deceleration threshold, the braking strength of the whole vehicle is emergency braking;

402. if the target deceleration is smaller than the first preset deceleration threshold and larger than the second preset deceleration threshold, the braking strength of the whole vehicle is moderate braking;

403. and if the target deceleration is smaller than a second preset deceleration threshold, the braking intensity of the whole vehicle is light braking.

In the above step 401, emergency braking means that when the whole vehicle encounters an emergency during driving, the whole vehicle needs to be stopped within a shortest distance, otherwise, other serious consequences may be caused, and in this case, the main task of the whole vehicle is to brake under safe conditions without considering the problem of energy recovery.

In step 402, the braking task is less urgent than in the case of emergency braking. If the moderate braking completely adopts the emergency braking mode to brake, safe braking can be realized, but the braking energy can be wasted. Therefore, moderate braking is a braking mode which can realize high recovery rate of braking energy under the condition of safe braking.

In the step 403, the light braking means that the safe braking of the whole vehicle can be realized without adopting a braking mode of emergency braking, and the braking energy recovery can be effectively realized.

According to the method provided by the embodiment, whether the whole vehicle is in an emergency condition or not can be judged through the target deceleration, so that the whole vehicle can realize safe braking and recovery of braking energy, and the braking safety of the whole vehicle is improved.

In a real-time example, before determining the braking mode of the whole vehicle according to the braking intensity, the total braking torque of the whole vehicle is determined according to the target deceleration.

The total braking torque refers to a torque required for braking the whole vehicle, and is determined according to the target deceleration, the parameters of the motor and the like. Specifically, after the brake controller obtains the target deceleration, the total braking torque required by the whole vehicle is calculated, and then the next control on the brake control system is carried out according to the total braking torque.

According to the method provided by the real-time example, the braking torque of the whole vehicle can be calculated through the obtained target deceleration, so that the safety braking of the whole vehicle is performed, and the safety of the whole vehicle in running is improved.

In a real-time example, the braking mode comprises hydraulic braking, electro-hydraulic hybrid braking and electric braking; correspondingly, according to the brake intensity, the brake mode of the whole vehicle is determined, and the method comprises the following steps:

501. if the braking strength of the whole vehicle is emergency braking, determining that the braking mode of the whole vehicle is hydraulic braking;

502. if the braking strength of the whole vehicle is moderate braking, determining that the braking mode of the whole vehicle is electro-hydraulic hybrid braking;

503. and if the braking strength of the whole vehicle is mild braking, determining that the braking mode of the whole vehicle is electric braking.

The electric braking is a braking mode that after the power supply of the motor is cut off, a braking torque opposite to the actual steering direction of the motor is generated, so that the motor is rapidly stopped. In the real-time example of the invention, the hydraulic brake is a brake mode that the brake controller controls the pressure of all wheel cylinders to brake the whole vehicle.

In step 501, when it is determined that the braking strength of the entire vehicle is emergency braking, it is indicated that the braking condition of the entire vehicle is relatively emergency, and if a correct braking manner cannot be adopted, a safety problem may occur.

In the step 502, when it is determined that the braking strength of the entire vehicle is moderate braking, it indicates that the braking condition of the entire vehicle is not too urgent, but the braking of the entire vehicle cannot be completed only by electric braking, so that the safety braking of the entire vehicle can be realized only by adopting electro-hydraulic hybrid braking, and the braking energy recovery and the safety braking of the entire vehicle can be realized by adopting the electro-hydraulic hybrid braking.

In the step 503, when it is determined that the braking strength of the entire vehicle is light braking, it indicates that the entire vehicle can be completely braked by the electric brake.

According to the method provided by the embodiment, the braking mode of the whole vehicle can be determined by determining the braking strength of the whole vehicle, so that the recovery rate of braking energy can be improved and the utilization rate of braking energy resources can be improved under the condition that the whole vehicle can be safely braked.

In one embodiment, electro-hydraulic hybrid braking includes electric braking and hydraulic braking; correspondingly, after the braking mode of the whole vehicle is determined to be electro-hydraulic hybrid braking, the method comprises the following steps:

601. acquiring the residual capacity of a storage battery of the whole vehicle;

602. and determining the braking proportion of electric braking and hydraulic braking in the electro-hydraulic hybrid braking according to the residual capacity of the storage battery.

Specifically, the electro-hydraulic hybrid braking is actually that the whole vehicle simultaneously adopts electric braking and hydraulic braking, and it is worth mentioning that the braking proportion of the electric braking and the hydraulic braking is not fixed, and when the whole vehicle adopts the electro-hydraulic hybrid braking, the distribution proportion of the electric braking and the hydraulic braking depends on the residual capacity of the storage battery.

More specifically, the braking energy recovery means that when the whole vehicle is braked, kinetic energy of the whole vehicle can be converted into electric energy through a braking control system and stored in a storage battery, and when the whole vehicle starts or accelerates, the electric energy of the storage battery can be converted into driving energy.

Specifically, the brake controller would first capture the remaining capacity of the battery, and then the brake controller would allocate the total braking torque by prioritizing electric braking for a battery full condition.

According to the method provided by the embodiment, the residual capacity of the storage battery is obtained through the brake controller, and the distribution mode of the braking torques of the electric brake and the hydraulic brake in the electro-hydraulic hybrid brake can be determined, so that the brake control system can intelligently adjust the proportional relation between the electric brake and the hydraulic brake, the electric brake can be preferentially adopted, and the recovery rate of the braking energy is greatly improved.

In one embodiment, braking the entire vehicle according to a braking mode comprises:

701. if the braking mode is hydraulic braking, the whole vehicle is braked by adopting hydraulic braking according to the total braking torque;

702. and if the braking mode is electric braking, the whole vehicle is braked by adopting electric braking according to the total braking torque.

In step 701, when the braking mode of the entire vehicle is determined to be hydraulic braking, the brake controller may apply hydraulic braking to the entire vehicle according to the total braking torque to perform braking, and when the braking is performed, the brake controller may perform double closed-loop control of the braking torque and the deceleration on the brake control system.

Specifically, the control process of the brake controller is as follows: the brake controller can acquire the actual deceleration of the whole vehicle, compares the actual deceleration with the target deceleration, calculates the error between the actual deceleration and the target deceleration, and if the error is greater than the preset error threshold of the brake controller, the brake controller can adjust the brake torque according to the target deceleration so as to adjust the actual deceleration. If the error is smaller than the preset error threshold value of the brake controller, the whole vehicle can decelerate at the actual deceleration.

In step 702, when the braking mode of the entire vehicle is determined as electric braking, the brake controller will apply electric braking to the entire vehicle according to the total braking torque, and during braking, the brake controller will perform double closed-loop control of braking torque and deceleration on the brake control system.

Specifically, the control process of the brake controller is as follows: the brake controller can acquire the actual deceleration of the whole vehicle, compare the actual deceleration with the target deceleration, calculate the error between the actual deceleration and the target deceleration, and if the error is greater than the preset error threshold of the brake controller, the brake controller can adjust the brake torque according to the target deceleration so as to adjust the actual deceleration. If the error is smaller than the preset error threshold value of the brake controller, the whole vehicle can decelerate at the actual deceleration.

The control method of the double closed-loop control in steps 701 and 702 is not specifically limited herein, and includes but is not limited to: PID control, PI control and fuzzy PID control.

According to the method provided by the embodiment, the braking of the whole vehicle can be realized through the determined braking mode, so that the whole vehicle can be braked within a safe distance, and the braking safety of the whole vehicle is improved.

In one embodiment, if the braking mode is electro-hydraulic hybrid braking; correspondingly, according to the braking mode, the whole vehicle is braked, and the method comprises the following steps:

801. determining the braking torque of electric braking and the braking torque of hydraulic braking in the electro-hydraulic hybrid braking according to the braking proportion and the total braking torque of the electric braking and the hydraulic braking in the electro-hydraulic hybrid braking;

802. and according to the braking torque of the electric brake and the braking torque of the hydraulic brake in the electro-hydraulic hybrid brake, the whole vehicle is braked by adopting the hydraulic hybrid brake.

In step 801, the brake controller may determine the braking torque of the electric brake in the electro-hydraulic hybrid brake, so as to determine the braking ratio of the electric brake and the hydraulic brake in the electro-hydraulic hybrid brake, and then determine the braking torque of the hydraulic brake in the electro-hydraulic hybrid brake according to the braking ratio.

For example, if the total braking torque is 10N · m, the electric brake needs 6N · m of braking torque to fully charge the battery, and the distribution ratio of the braking torque of the electric brake and the hydraulic brake in the electro-hydraulic hybrid brake is: braking torque of electric brake: braking torque of hydraulic braking 3: 2, the distributed braking torque of the hydraulic brake is 4 N.m.

In step 802, when the braking mode of the entire vehicle is determined to be the electro-hydraulic hybrid braking, the brake controller may perform the electro-hydraulic hybrid braking on the entire vehicle according to the braking torque of the hydraulic braking of the electric braking, and during the braking, the brake controller may perform the dual closed-loop control of the braking torque and the deceleration on the braking control system.

According to the method provided by the embodiment, when the braking mode of the whole vehicle is determined to be electro-hydraulic hybrid braking, braking torque can be distributed through electric braking and hydraulic braking, so that the recovery rate of braking energy is improved, and the utilization rate of resources is further improved.

It should be understood that, although the steps in the flowchart in fig. 2 are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least a portion of the steps in fig. 2 may include multiple steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, which are not necessarily performed in sequence, but may be performed in turn or alternately with other steps or at least a portion of the other steps or stages.

It should be noted that the technical solutions described above may be implemented as independent embodiments in actual implementation processes, or may be combined with each other and implemented as combined embodiments. In addition, when the contents of the embodiments of the present invention are described above, the different embodiments are described according to the corresponding sequence only based on the idea of convenient description, for example, the sequence of the data flow is not limited to the execution sequence between the different embodiments, nor is the execution sequence of the steps in the embodiments limited. Accordingly, in the actual implementation process, if it is necessary to implement multiple embodiments provided by the present invention, the execution sequence provided in the embodiments of the present invention is not necessarily required, but the execution sequence between different embodiments may be arranged according to requirements.

A brake control system for an autonomous flatbed vehicle, the system being shown in fig. 3, the system comprising: an external controller 310, a brake controller 311, a wheel cylinder pressure sensor 312, a master circuit pressure sensor 313, an accumulator 314, a motor 315, a hydraulic pump 316, a manual pump 317, an overflow valve 318, an oil tank 319, a wheel cylinder 320, a brake pressure-reducing valve 321, a deceleration sensor 322, and a battery 323, wherein:

the external controller 310 is used for sending a control command according to the requirement of the whole vehicle, and receiving the brake torque sent to the brake control system by the brake controller and the feedback state of the brake control system;

the brake controller 311 is used for controlling the whole vehicle according to the control instruction;

a wheel cylinder pressure sensor 312 for monitoring wheel cylinder pressure of the entire vehicle, and feeding back a pressure state to an external controller through a brake controller when the pressure is insufficient or excessive;

a pressure sensor 313 for acquiring the pressure of the main circuit and transmitting the pressure to the brake controller;

an accumulator 314 for storing energy to ensure that the pressure in the main circuit is maintained at a normal level;

a motor 315 for powering the hydraulic pump;

a hydraulic pump 316 for building pressure to the main circuit of the brake control system;

a manual pump 317 for building pressure on the main circuit of the brake control system by means of the manual pump when the hydraulic pump fails;

the overflow valve 318 is used for controlling the pressure of the main loop of the brake control system to be maintained at a preset pressure threshold value, and when the pressure of the main loop of the brake control system exceeds the preset pressure threshold value, the overflow valve unloads the pressure to return to the oil tank;

an oil tank 319 for storing hydraulic oil with an energy of 0;

the wheel cylinder 320 is used for controlling the running or braking of the whole vehicle according to the hydraulic pressure in the wheel cylinder;

the brake pressure reducing valve 321 is used for controlling the hydraulic pressure of the wheel cylinder to realize closed-loop control of the braking torque and pressure of hydraulic braking;

the deceleration sensor 322 is used for detecting the actual deceleration of the vehicle and returning the actual deceleration to the brake controller to realize the closed-loop control of the deceleration of the whole vehicle;

and the storage battery 323 is used for providing a power supply for the whole vehicle, and can recover energy when the whole vehicle adopts electric braking.

In the brake control system, the brake controller 311 is responsible for controlling the entire brake control system, and it needs to receive a control instruction from an external controller and regulate and control the brake control system according to the control instruction, and also needs to feed back the state of the brake control system to the external controller, and at the same time, needs to receive values acquired by all sensors in the brake control system and control the corresponding modules according to the values.

Wheel cylinder pressure sensors 312 are: the front axle left wheel cylinder pressure sensor is used for acquiring the pressure of a front axle left wheel cylinder; the front axle right wheel cylinder pressure sensor is used for acquiring the pressure of a front axle right wheel cylinder; the rear axle left wheel cylinder pressure sensor is used for acquiring the pressure of a rear axle left wheel cylinder; and the rear axle right wheel cylinder pressure sensor is used for acquiring the pressure of the front axle right wheel cylinder.

Accumulators 314, first and second accumulators, respectively: when the whole vehicle runs, the accumulator is used for realizing the pressure stabilizing function when the pressure of a main loop of the brake control system is insufficient or excessive.

Wheel cylinders 320, which are a front axle left wheel cylinder, a front axle right wheel cylinder, a rear axle left wheel cylinder, and a rear axle left wheel cylinder, respectively: when the hydraulic pressure of the wheel cylinder is increased to a first wheel cylinder pressure threshold value, the corresponding wheel is controlled to move, and when the hydraulic pressure of the wheel cylinder is decreased to a second wheel cylinder pressure threshold value, the wheel corresponding to the whole vehicle is controlled to stop moving.

The brake pressure reducing valves 321 are a front axle left wheel brake pressure reducing valve, a front axle right wheel brake pressure reducing valve, a rear axle left wheel brake pressure reducing valve, and a rear axle right wheel brake pressure reducing valve, respectively.

In one embodiment, the above-described brake control system is applied to the state transition of the brake control system of fig. 4. Each state is divided into an upper part, a middle part and a lower part, the upper part is the state name of the brake control system, the middle part is the state variable name and the numerical value, and the lower part is the activity in the current state. The links between the states are events, which are control information that cause the brake control system to act or change states.

1. Initialization state is 0: and (5) initializing a brake control system.

2. Ready state 1: after the whole vehicle is ignited, the whole vehicle is electrified, and the motor and the hydraulic pump are controlled to operate, so that the pressure of a main loop of the brake control system is increased. In addition, when the pressure of the brake control system is built up, if the whole vehicle is shut down, the whole vehicle is directly switched from a preparation state to a stop state, and the pressure of the brake control system is unloaded at the moment.

3. Operating state 2: when the pressure of a main loop of the brake control system is detected to be stabilized at P Mpa through a main loop pressure sensor, a control command of an external controller can be obtained, when no brake request or no driving request exists, all wheel cylinders are filled with liquid oil through a brake pressure reducing valve, the parking brake of the whole vehicle is released, and the vehicle has a driving condition. When the brake controller receives an external controller brake deceleration request, the deceleration closed-loop control is realized through a brake energy recovery strategy.

4. Stop state 3: when the brake control system is flamed out in a preparation state or an operation state, the brake control system jumps to a stop state, and the pressure of the wheel cylinders of the front shaft and the rear shaft is unloaded through the brake pressure reducing valve, so that the pressure of a main loop of the brake control system is reduced to 0.

5. End state 4: and after the pressure unloading of the brake control system is finished, the brake control system enters an ending State, the State State is set to be 0, the brake control system is switched to an initialization State, and the next operation of the brake control system is waited.

Specifically, after the brake control system is powered on, the pressure of the brake control system is built by waiting for the ignition action, and when the pressure of the brake control system is stabilized at the working pressure P Mpa, the brake control system can analyze the deceleration control instruction sent by the external controller and control the pressure of the brake pressure reducing valve wheel cylinder. When a flameout command is received in any process, the wheel cylinder pressure is unloaded, then the pressure of the main loop of the brake control system is unloaded, and the next ignition action is waited.

In connection with the above embodiments, in one embodiment, the braking energy recovery control strategy is as shown in FIG. 5. When the whole vehicle is braked, the condition that the target deceleration absolute value is greater than 0.7g is emergency braking, and hydraulic braking should be preferentially adopted to ensure the braking safety. And under the condition of non-emergency braking, judging whether the electric braking energy completely meets the braking intensity requirement according to the target deceleration, if so, performing mild braking, and if not, performing moderate braking, calculating the braking torque of the electric braking and the hydraulic braking, and preferentially considering the electric braking when performing electric-industry hybrid braking, thereby increasing the recovery rate of the braking energy.

In addition, for medium braking and emergency braking with hydraulic braking, the braking torque of each wheel is the same, that is, the control voltage for each brake pressure reducing valve is the same, in order to ensure the braking stability. The pressure control of the brake pressure reducing valve is realized through a PID control algorithm, and the closed-loop control of the brake torque is realized through the PID control algorithm.

According to the system provided by the embodiment of the invention, if the control instruction is analyzed to be the braking request, the target deceleration of the braking request is obtained, and the control instruction is used for indicating the control instruction sent by the external controller according to the requirement of the whole vehicle; judging the braking strength of the whole vehicle according to the target deceleration; determining the braking mode of the whole vehicle according to the braking strength; and braking the whole vehicle according to the braking mode. Compared with the prior art that only the recovery rate of the braking energy is considered when the whole vehicle is braked, the braking intensity of the whole vehicle can be graded according to the target deceleration, so that the corresponding braking mode is selected to realize the braking of the whole vehicle, and the recovery of the braking energy can be realized under the condition of safe braking, thereby improving the safety of the whole vehicle and the recovery rate of the braking energy.

For specific limitations of the brake control system of the autonomous flatbed, reference may be made to the above limitations of the brake control method of the autonomous flatbed, which are not described in detail herein. The various modules in the brake control system of the above-described autonomous flatbed may be implemented in whole or in part by software, hardware, and combinations thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.

In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as shown in fig. 6. The computer device includes a processor, a memory, and a network interface connected by a system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device comprises a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of an operating system and computer programs in the non-volatile storage medium. The database of the computer device is used for storing the preset threshold value. The network interface of the computer device is used for communicating with an external terminal through a network connection. The computer program is executed by a processor to implement a brake control method of an autonomous flat car.

Those skilled in the art will appreciate that the architecture shown in fig. 6 is merely a block diagram of some of the structures associated with the disclosed aspects and is not intended to limit the computing devices to which the disclosed aspects apply, as particular computing devices may include more or less components than those shown, or may combine certain components, or have a different arrangement of components.

In one embodiment, a computer device is provided, comprising a memory and a processor, the memory having a computer program stored therein, the processor implementing the following steps when executing the computer program:

judging the braking strength of the whole vehicle according to the target deceleration;

determining the braking mode of the whole vehicle according to the braking strength;

and braking the whole vehicle according to the braking mode.