CN114715087B - Automatic braking method, device and system for vehicle and storage medium - Google Patents

Automatic braking method, device and system for vehicle and storage medium Download PDF

Info

Publication number
CN114715087B
CN114715087B CN202110004846.2A CN202110004846A CN114715087B CN 114715087 B CN114715087 B CN 114715087B CN 202110004846 A CN202110004846 A CN 202110004846A CN 114715087 B CN114715087 B CN 114715087B
Authority
CN
China
Prior art keywords
vehicle
current
deceleration
current vehicle
braking
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110004846.2A
Other languages
Chinese (zh)
Other versions
CN114715087A (en
Inventor
郑志晓
梁伟强
林志超
蔡璐珑
王博
钟国旗
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Guangzhou Automobile Group Co Ltd
Original Assignee
Guangzhou Automobile Group Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Guangzhou Automobile Group Co Ltd filed Critical Guangzhou Automobile Group Co Ltd
Priority to CN202110004846.2A priority Critical patent/CN114715087B/en
Publication of CN114715087A publication Critical patent/CN114715087A/en
Application granted granted Critical
Publication of CN114715087B publication Critical patent/CN114715087B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T7/00—Brake-action initiating means
    • B60T7/12—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T2201/00—Particular use of vehicle brake systems; Special systems using also the brakes; Special software modules within the brake system controller
    • B60T2201/02—Active or adaptive cruise control system; Distance control
    • B60T2201/022—Collision avoidance systems
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

Landscapes

  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Regulating Braking Force (AREA)

Abstract

The invention discloses an automatic braking method, device and system of a vehicle and a storage medium, wherein the method comprises the following steps: calculating the collision time and the expected relative distance between the current vehicle and the target vehicle; judging whether the current running state of the vehicle is a driver braking state or not; when the first braking condition is met, braking the brake actuator according to the current running speed of the current vehicle; when the second braking condition is met, if the predicted relative distance is greater than the safe distance threshold, calculating the required deceleration of the current vehicle according to the predicted relative distance, and sending a corresponding deceleration instruction to a braking actuator of the current vehicle according to the required deceleration; and when the collision time is not greater than the third collision time, braking the brake actuator according to the maximum deceleration which can be executed by the brake actuator of the current vehicle. The invention can adjust the braking deceleration according to the actual running condition of the vehicle by avoiding the mutual drag of the primary braking and the secondary braking, thereby improving the safety of the braking process.

Description

Automatic braking method, device and system for vehicle and storage medium
Technical Field
The present invention relates to the field of control technologies of vehicle driving systems, and in particular, to a method, an apparatus, a system, and a storage medium for automatically braking a vehicle.
Background
In the running process of the automobile with the forward anti-collision system, the collision time of the automobile can be calculated, automatic braking of the automobile is realized according to the collision time, and the situation that a driver reacts or brakes untimely is avoided.
Currently, common driving assistance forward collision avoidance systems include both early warning and automatic emergency braking functions. The common automatic emergency braking is open-loop braking, each stage of braking judges whether a braking triggering condition is met according to TTC (Time to Collision, collision time), each stage of braking deceleration is set to a fixed value, and the TTC is triggered through calibration, so that the safety distance is controlled. However, in the conventional braking system, the braking at each level is mutually restricted, and the braking deceleration at each level is fixed, so that it is difficult to satisfy the actual braking situation.
Disclosure of Invention
The embodiment of the invention provides an automatic braking method, an automatic braking device, an automatic braking system and a storage medium of a vehicle, which can adjust braking deceleration according to actual running conditions of the vehicle by avoiding mutual restriction of primary braking and secondary braking, thereby improving the safety of the braking process.
An embodiment of the present invention provides an automatic braking method for a vehicle, including:
calculating the collision time and the expected relative distance between the current vehicle and the target vehicle;
Acquiring the running state of a current vehicle, and judging whether the running state of the current vehicle is a driver braking state or not;
when a first braking condition is met, a corresponding deceleration instruction is sent to a braking actuator of the current vehicle according to the current running speed of the current vehicle; wherein the first braking condition includes that the running state of the current vehicle is not a driver braking state and the collision time is not greater than a first collision time;
when a second braking condition is met, if the expected relative distance is greater than a safe distance threshold, calculating the required deceleration of the current vehicle according to the expected relative distance, sending a corresponding deceleration instruction to a braking actuator of the current vehicle according to the required deceleration, and if the expected relative distance is not greater than the safe distance threshold, sending a corresponding deceleration instruction to the braking actuator of the current vehicle according to the maximum executable deceleration of the braking actuator of the current vehicle; wherein the second braking condition includes that the running state of the current vehicle is not a driver braking state and the collision time is not greater than a second collision time; the second collision time is less than the first collision time and greater than a third collision time;
And when the collision time is not more than the third collision time, sending a corresponding deceleration instruction to the brake actuator of the current vehicle according to the maximum executable deceleration of the brake actuator of the current vehicle.
As an improvement of the above scheme, the method further comprises:
when the running state of the current vehicle is a driver braking state, executing the following steps:
judging whether the current running speed of the current vehicle is greater than a first running speed threshold value or not;
when the current running speed of the current vehicle is not greater than a first running speed threshold value and the predicted relative distance is greater than a safe distance threshold value, not braking;
when the current running speed of the current vehicle is greater than a first running speed threshold, the collision time is not greater than a second collision time, and the expected relative distance is greater than a safety distance threshold, calculating the required deceleration of the current vehicle according to the expected relative distance, and sending a corresponding deceleration instruction to a brake actuator of the current vehicle according to the required deceleration.
As an improvement of the above aspect, the calculating the collision time of the current vehicle with the target vehicle includes:
acquiring the current running speed of the current vehicle, and acquiring the current running speed of the target vehicle and the running state of the target vehicle;
When the current running speed of the current vehicle is greater than the current running speed of the target vehicle and the running state of the target vehicle is a decelerating state, the collision time is calculated by the following equation:
Figure BDA0002882806990000031
when the current running speed of the current vehicle is greater than the current running speed of the target vehicle and the running state of the target vehicle is not a decelerating state, the collision time is calculated by:
Figure BDA0002882806990000032
when the current running speed of the current vehicle is not greater than the current running speed of the target vehicle, enabling the collision time to be TTC';
in the formula, v sv1 V, the current running speed of the current vehicle to1 For the current running speed of the target vehicle, S rel A, for a current expected relative distance between the current vehicle and the target vehicle to1 And TTC' is a preset collision time calibration value for the current speed change rate of the target vehicle.
As an improvement of the above-described aspect, when the second braking condition is satisfied, further comprising:
acquiring the current deceleration of the current vehicle;
when the current speed change rate of the current vehicle is smaller than a preset deceleration state threshold value, judging that the running state of the current vehicle is a deceleration state, and setting the brake delay time of a brake actuator of the current vehicle to be 0;
When the current speed change rate of the current vehicle is not smaller than a preset deceleration state threshold value, judging that the running state of the current vehicle is not a deceleration state, and setting the braking delay time of a braking actuator of the current vehicle, wherein the braking delay time is not 0;
when the braking delay time is not 0, respectively calculating first expected running distances of the current vehicle and the target vehicle, and calculating an expected relative distance between the current vehicle and the target vehicle according to the first expected running distances of the current vehicle and the target vehicle; wherein the predicted relative distance is a first predicted relative distance;
wherein the first estimated travel distance of the current vehicle is calculated by:
Figure BDA0002882806990000041
calculating a first estimated travel distance of the target vehicle by:
Figure BDA0002882806990000042
/>
the first expected relative distance is calculated by:
S rel_1 ＝S to1 －S sv1 +S rel
wherein a is sv1 T is the current speed change rate of the current vehicle delay For the braking delay time, S sv1 For a first expected travel distance of the current vehicle, S to1 For a first expected travel distance of the target vehicle, S rel_1 Is a first expected relative distance between the current vehicle and the target vehicle.
As an improvement of the above-described aspect, when the brake delay time is 0 and the current deceleration of the current vehicle is incremented, the deceleration value corresponding to the deceleration instruction of the previous cycle is taken as the initial deceleration, and the incremented deceleration is calculated according to the initial deceleration;
calculating a second estimated travel distance of the current vehicle and the target vehicle, respectively, based on the incremental deceleration, and calculating an estimated relative distance between the current vehicle and the target vehicle based on the second estimated travel distance of the current vehicle and the target vehicle; wherein the predicted relative distance is a second predicted relative distance;
wherein the incremental deceleration is calculated from the initial deceleration according to:
decelt 1 ＝min(decel t0 +b，decel max /2)
in the formula, decel t1 To increase the deceleration, decel t0 For initial deceleration, decel max A maximum deceleration that is executable for a brake actuator of the current vehicle; b is the increment, when decel t0 When=0, let b=excel max 2, when decel t0 When not equal to 0, let
Figure BDA0002882806990000051
Wherein m is an integer, j is the deceleration rate; when the current deceleration of the current vehicle is smaller than the initial deceleration decel t0 When j is>0; when the current deceleration of the current vehicle is equal to the initial deceleration decel t0 When j=0; when the current deceleration of the current vehicle is greater than the initial deceleration decel t0 When j is<0；
A second estimated travel distance of the current vehicle during deceleration ramp up is calculated by:
Figure BDA0002882806990000052
a second estimated travel distance of the target vehicle during deceleration ramp up is calculated by:
Figure BDA0002882806990000053
calculating a second predicted relative distance between the current vehicle and the target vehicle by:
S rel_2 ＝S to2 －S sv2 +S rel
wherein a is sv1 T is the current speed change rate of the current vehicle delay For the braking delay time, t 2 Time is increased for deceleration, and
Figure BDA0002882806990000054
S sv2 for a second expected distance of travel of the current vehicle, S to2 For a second expected travel distance of the target vehicle, S rel_2 A second expected relative distance between the current vehicle and the target vehicle.
As an improvement of the above scheme, the method further comprises:
when the braking delay time is 0 and the deceleration change rate is 0, calculating third running distances of the current vehicle and the target vehicle according to the incremental deceleration, and calculating an estimated relative distance between the current vehicle and the target vehicle according to the third estimated running distances of the current vehicle and the target vehicle, respectively; wherein the predicted relative distance is a third predicted relative distance;
Wherein the third estimated travel distance of the current vehicle is calculated by:
Figure BDA0002882806990000061
a third estimated travel distance of the target vehicle is calculated by:
Figure BDA0002882806990000062
calculating the travel time of the current vehicle at the incremental deceleration by:
Figure BDA0002882806990000063
calculating a third expected relative distance between the current vehicle and the target vehicle by:
S rel_3 ＝S to3 －S sv3 +S rel
wherein t is 3 For the travel time of the current vehicle at the incremental deceleration, S sv3 For a third expected travel distance of the current vehicle, S to3 For a third expected travel distance of the target vehicle, S rel_3 A third expected relative distance between the current vehicle and the target vehicle.
As an improvement of the above scheme, the method further comprises:
and when the predicted relative distance is greater than a safe distance threshold, taking the incremental deceleration as the required deceleration, and sending a corresponding deceleration instruction to a brake actuator of the current vehicle according to the required deceleration.
As an improvement of the above scheme, the method further comprises: the second collision time is greater than the third collision time;
the third collision time is obtained according to the current running speeds of the current vehicle and the target vehicle;
Wherein the third collision time is calculated by:
Figure BDA0002882806990000064
in TTC threshold_3 And the third collision time.
Another embodiment of the present invention correspondingly provides an automatic braking device for a vehicle, including:
the parameter calculation module is used for calculating the collision time and the expected relative distance between the current vehicle and the target vehicle;
the state acquisition module is used for acquiring the running state of the current vehicle and judging whether the running state of the current vehicle is a driver braking state or not;
a brake control module for:
when a first braking condition is met, a corresponding deceleration instruction is sent to a braking actuator of the current vehicle according to the current running speed of the current vehicle; wherein the first braking condition includes that the running state of the current vehicle is not a driver braking state and the collision time is not greater than a first collision time;
when a second braking condition is met, if the expected relative distance is greater than a safe distance threshold, calculating the required deceleration of the current vehicle according to the expected relative distance, sending a corresponding deceleration instruction to a braking actuator of the current vehicle according to the required deceleration, and if the expected relative distance is not greater than the safe distance threshold, sending a corresponding deceleration instruction to the braking actuator of the current vehicle according to the maximum executable deceleration of the braking actuator of the current vehicle; wherein the second braking condition includes that the running state of the current vehicle is not a driver braking state and the collision time is not greater than a second collision time; the second collision time is less than the first collision time and greater than a third collision time;
And when the collision time is not more than the third collision time, sending a corresponding deceleration instruction to the brake actuator of the current vehicle according to the maximum executable deceleration of the brake actuator of the current vehicle.
Another embodiment of the present invention provides a control system for an autonomous vehicle, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, where the processor executes the computer program to implement the method for automatically braking a vehicle according to the embodiment of the present invention.
Another embodiment of the present invention provides a storage medium, where the computer readable storage medium includes a stored computer program, where when the computer program runs, the device where the computer readable storage medium is located is controlled to execute the automatic braking method of the vehicle according to the embodiment of the present invention.
Compared with the prior art, in the embodiment of the invention, the running state of the vehicle is judged through the depth of the brake pedal and the pressure of the brake master cylinder, so that the misjudgment of the braking state of a driver is avoided; under the condition that the vehicle is not in a driver braking state, the collision time of the current vehicle and the front vehicle, namely the target vehicle, is calculated, so that the braking condition can be timely obtained, and the safety and timeliness of automatic braking are improved; the first-stage open-loop braking is triggered when the collision time is not longer than the first collision time, and a corresponding first deceleration instruction is sent to a brake actuator of the current vehicle according to the current running speed of the current vehicle, so that the startle and the danger caused by excessively rapid deceleration or unnecessary emergency braking are avoided, the safety of the vehicle braking is improved, and the comfort level of a driver and other passengers can be improved; the second-level closed-loop control is triggered when the collision time is not longer than the second collision time, and the braking deceleration is calculated in real time according to the states of the current vehicle and the target vehicle, so that the decoupling of the first-level braking and the second-level braking is realized, the triggering time is not mutually contained, the braking deceleration is regulated according to the actual running condition of the vehicle, and the safety of the braking process is further improved; through judging the safe collision distance, when the predicted relative distance is still larger than the safe distance threshold value, the time for decelerating according to the vehicle speed is indicated to be still provided at present, and at the moment, the required deceleration of the current vehicle can be calculated according to the parameters such as the predicted relative distance, the vehicle speed of the current vehicle, the vehicle speed of the target vehicle and the like; when the vehicle is in a driver braking state, taking the braking behavior of the driver into consideration, and providing braking control assistance for the driver taking braking measures as little as possible in a low-speed scene; when a collision is imminent, the vehicle is braked to a stop by a maximum braking force, so that the safety braking is realized on the premise of ensuring the safety and comfort of drivers and other passengers.
Drawings
FIG. 1 is a schematic flow chart of an automatic braking method for a vehicle according to an embodiment of the present invention;
FIG. 2 is a schematic diagram illustrating a specific control procedure of an automatic braking method of a vehicle according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a secondary braking specific control process of an automatic braking method of a vehicle according to an embodiment of the present invention;
fig. 4 is a schematic structural view of an automatic braking device for a vehicle according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a control system for an automatic driving vehicle according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Embodiment one:
referring to fig. 1, a schematic flow chart of an automatic braking method of a vehicle according to an embodiment of the present invention is shown.
The automatic braking method of the vehicle provided by the embodiment can be executed by the automatic braking control end. In this embodiment, the automatic braking control end is preferably a control system of an automatic braking vehicle, and may also be a cloud server, where the control system may be implemented in a software and/or hardware manner, and the control system may be configured by two or more physical entities or may be configured by one physical entity.
Further, the control system can acquire the vehicle running state information such as the speed, acceleration, and vehicle braking state transmitted from each running state information generating device of the vehicle. When the above-described various information is to be transmitted directly to the control system, the information may be transmitted to another information processing apparatus, and the information processing apparatus may transmit the processed information to the control system after the corresponding information processing.
Specifically, referring to fig. 1, the automatic braking method of the vehicle includes steps S101 to S105:
s101, calculating the collision time and the expected relative distance between the current vehicle and the target vehicle;
the method and the device can acquire braking conditions in time and improve the safety and timeliness of automatic braking by calculating the collision time and the expected relative distance between the current vehicle and the front vehicle (namely the target vehicle).
S102, acquiring the running state of the current vehicle, and judging whether the running state of the current vehicle is a driver braking state or not;
specifically, the running state of the current vehicle is obtained by the following method: acquiring the current depth of a brake pedal of a vehicle and the pressure of a brake master cylinder; judging whether the depth of a brake pedal is higher than a preset pedal depth threshold value or not, and judging whether the pressure of a brake master cylinder is higher than a preset pressure threshold value or not; when the depth of the brake pedal is higher than a preset pedal depth threshold value, and the pressure of the brake master cylinder is higher than a preset pressure threshold value and is maintained for a certain time, judging that a driver has taken braking measures, namely that the current running state of the vehicle is a driver braking state; otherwise, it is determined that the driver does not take braking measures, i.e., the current running state of the vehicle is not the driver braking state.
The travel state of the vehicle is judged through the depth of the brake pedal and the pressure of the brake master cylinder, so that the driver can be ensured to take braking measures at the moment, the vehicle receives a braking instruction and starts braking, misjudgment of the braking state of the driver is avoided, and the stability of automatic braking is improved.
It should be noted that, according to the brake pedal depth and the brake master cylinder pressure, it is a preferable mode in the present embodiment, specifically, whether the current vehicle is in the driver braking state is obtained according to only the brake pedal depth, only the brake master cylinder pressure, or according to other existing modes, which is not particularly limited herein.
When the running state of the current vehicle is not the driver braking state, the driver can not brake or brake in time, and at the moment, the braking condition can be timely obtained by calculating the collision time and the expected relative distance between the two vehicles, so that the safety and timeliness of automatic braking are improved.
S103, when the first braking condition is met, a corresponding deceleration instruction is sent to a brake actuator of the current vehicle according to the current running speed of the current vehicle; the first braking condition comprises that the running state of the current vehicle is not a driver braking state and the collision time is not longer than the first collision time;
when the collision time is not greater than the first collision time, the emergency degree of the current vehicle braking is low, so that a corresponding proper braking deceleration request can be sent to a brake actuator according to the running speed of the current vehicle. Specifically, the braking deceleration may be set as a one-dimensional table linearly interpolated from the vehicle speed, which may empirically calibrate the first time to collision TTC threshold_1 And the like, are not particularly limited herein. By performing adaptive automatic braking when the collision time is not greater than the first collision time, startles and hazards caused by too fast deceleration or unnecessary emergency braking are avoided, The safety of the vehicle braking is improved and the comfort of the driver and other occupants can be improved.
S104, when the second braking condition is met, if the expected relative distance is greater than a safe distance threshold, calculating the required deceleration of the current vehicle according to the expected relative distance, sending a corresponding deceleration instruction to a brake actuator of the current vehicle according to the required deceleration, and if the expected relative distance is not greater than the safe distance threshold, sending a corresponding deceleration instruction to the brake actuator of the current vehicle according to the maximum deceleration executable by the brake actuator of the current vehicle; wherein the second braking condition includes that the running state of the current vehicle is not a driver braking state and the collision time is not greater than the second collision time; the second collision time is less than the first collision time and greater than the third collision time;
wherein, since the second collision time is smaller than the first collision time, an increase in the degree of urgency of the current vehicle braking is indicated when the collision time is not longer than the second collision time, i.e., further braking is required according to the predicted relative distance at this time. The emergency degree judgment of braking is realized by judging the collision time, so that the braking safety can be improved, and the traditional secondary braking can be decoupled; if the collision time is not more than the first collision time, the collision time is not more than the second collision time, the first-stage braking is the first-stage open-loop braking for deceleration, the triggering time and the deceleration can be calibrated according to experience, the second-stage braking is the second-stage closed-loop braking for collision avoidance and safe distance control, the triggering time can be calibrated but not less than the time required for avoiding collision, and the braking deceleration is calculated in real time according to the states of the current vehicle and the target vehicle; therefore, decoupling of primary braking and secondary braking can be realized, triggering time of the primary braking and the secondary braking is not mutually limited, braking deceleration is adjusted according to actual running conditions of the vehicle, and safety of a braking process is further improved.
The second collision time is smaller than the first collision time and larger than the third collision time, and the second collision time is set in the range, so that the problem that the braking is not achieved due to too small collision time can be avoided.
When the predicted relative distance is still greater than the safe distance threshold, the time for decelerating according to the vehicle speed is still provided, and at the moment, the required deceleration of the current vehicle can be calculated according to the parameters such as the predicted relative distance, the vehicle speed of the current vehicle, the vehicle speed of the target vehicle and the like; otherwise, if the predicted relative distance is not greater than the safe distance threshold, it is indicated that the current vehicle needs to perform emergency braking at the moment, so that a corresponding deceleration instruction needs to be sent to the brake actuator of the current vehicle according to the maximum deceleration executable by the brake actuator of the current vehicle, so that the actuator decelerates at the maximum deceleration which can be achieved by the brake actuator; thereby realizing safe braking on the premise of ensuring the safety and comfort of drivers and other passengers.
Specifically, the predicted relative distance between the current vehicle and the target vehicle can be calculated in real time in the running process of the current vehicle, and whether the predicted relative distance is larger than a safe distance threshold value is judged in real time, so that emergency braking is realized in time, and the safety of the current vehicle in the running process is ensured.
S105, when the collision time is not more than the third collision time, a corresponding deceleration instruction is sent to the brake actuator of the current vehicle according to the maximum deceleration executable by the brake actuator of the current vehicle;
for example, referring to fig. 2, when the collision time is not greater than the third collision time, it indicates that the brake urgency of the current vehicle is the greatest at this time, i.e., the collision is imminent, and braking is required at the maximum deceleration that can be performed by the brake actuator of the largest current vehicle so as to avoid the collision with the preceding vehicle.
In this embodiment, preferably, the method further includes: when the current running state of the vehicle is the driver braking state, the following steps are performed:
judging whether the current running speed of the current vehicle is greater than a first running speed threshold value or not;
when the current running speed of the current vehicle is not greater than the first running speed threshold value and the predicted relative distance is greater than the safe distance threshold value, not braking;
when the current running speed of the current vehicle is greater than the first running speed threshold, the collision time is not greater than the second collision time, and the predicted relative distance is greater than the safe distance threshold, the required deceleration of the current vehicle is calculated according to the predicted relative distance, and a corresponding deceleration instruction is sent to a brake actuator of the current vehicle according to the required deceleration.
For example, referring to fig. 2, when the current running state of the vehicle is not the driver braking state, it is determined that the driver does not take braking measures, it is determined whether the collision time is greater than the first collision time, and it is determined that the primary open-loop brake is triggered when the collision time is not greater than the first collision time; triggering a secondary closed-loop brake if the collision time of the current vehicle and the front vehicle is reduced and is smaller than the second collision time along with the continuous running of the vehicle; during braking, whether the expected relative distance is larger than a safe distance threshold value is judged, if the expected relative distance is not larger than the safe distance threshold value, the collision is judged to be about to happen at the moment, and therefore the brake actuator is controlled to brake with the maximum braking force.
For example, referring to fig. 2, when the running state of the current vehicle is a driver braking state, it is determined that the driver has taken braking measures, and at this time, whether the current is a low-speed running scene is determined by the current running speed of the current vehicle and the first running speed threshold value, and if the current running speed is not greater than the first running speed threshold value, it is determined that the current is a low-speed running scene, and automatic braking is not performed; if the vehicle is not in a low-speed driving scene, a secondary closed-loop braking link is entered, so that collision accidents caused by insufficient deceleration controlled by a driver are avoided.
Specifically, in consideration of the braking behavior of the driver, in the case where the driver has taken braking measures and is traveling at a low speed, braking control assistance is not provided to the driver who has taken braking measures as much as possible, avoiding affecting the driving experience of the driver, and when a collision is imminent, braking with the maximum braking force to the stop of the vehicle.
In the present embodiment, preferably, calculating the collision time of the current vehicle with the target vehicle includes:
acquiring the current running speed of the current vehicle, and acquiring the current running speed of the target vehicle and the running state of the target vehicle;
when the current running speed of the current vehicle is greater than the current running speed of the target vehicle and the running state of the target vehicle is a decelerating state, the collision time is calculated by:
Figure BDA0002882806990000131
when the current running speed of the current vehicle is greater than the current running speed of the target vehicle and the running state of the target vehicle is not a decelerating state, the collision time is calculated by:
Figure BDA0002882806990000132
when the current running speed of the current vehicle is not greater than the current running speed of the target vehicle, enabling the collision time to be TTC';
in the formula, v sv1 V is the current running speed of the current vehicle to1 For the current running speed of the target vehicle S rel A is the current expected relative distance between the current vehicle and the target vehicle to1 The TTC' is a preset collision time calibration value for the current speed change rate of the target vehicle.
Specifically, if the target vehicle has started decelerating, a to1 ＜-1.0m/s 2 。
Specifically, a proper collision time TTC is selected according to the current running speeds of the current vehicle and the target vehicle and the current speed change of the target vehicle, and if the calculated collision time is greater than a preset collision time calibration value TTC ', the preset collision time calibration value TTC' is selected as the collision time TTC, so that emergency braking time of an emergency is reserved; for the same reason, if the current running speed of the current vehicle is not greater than the current running speed of the target vehicle, i.e., v sv1 -v to1 When the collision time is less than or equal to 0, the collision time is TTC'.
It should be noted that, in the above embodiment, the preset time to collision calibration TTC' may be selected to be 10.0s, and may be set to be 10.5s, 11.0s, 12.0s, etc. according to the actual situation of the vehicle due to the driving system and the control system of the vehicle, which only provides an alternative embodiment without specific limitation.
In the present embodiment, preferably, when the second braking condition is satisfied, further comprising:
Acquiring the current deceleration of the current vehicle;
when the current speed change rate of the current vehicle is smaller than a preset deceleration state threshold value, judging that the running state of the current vehicle is a deceleration state, and setting the brake delay time of a brake actuator of the current vehicle to be 0;
when the current speed change rate of the current vehicle is not smaller than a preset deceleration state threshold value, judging that the running state of the current vehicle is not a deceleration state, and setting the braking delay time of a braking actuator of the current vehicle, wherein the braking delay time is not 0;
when the braking delay time is not 0, respectively calculating first estimated travel distances of the current vehicle and the target vehicle, and calculating an estimated relative distance between the current vehicle and the target vehicle according to the first estimated travel distances of the current vehicle and the target vehicle; wherein the predicted relative distance is a first predicted relative distance;
wherein the first estimated travel distance of the current vehicle is calculated by:
Figure BDA0002882806990000141
a first estimated travel distance of the target vehicle is calculated by:
Figure BDA0002882806990000151
the first expected relative distance is calculated by:
S rel_1 ＝S to1 －S sv1 +S rel
wherein a is sv1 T is the current speed change rate of the current vehicle delay For braking delay time, S sv1 For a first estimated distance travelled by the current vehicle S to1 For a first expected travel distance of the target vehicle S rel_1 Is a first expected relative distance between the current vehicle and the target vehicle.
For example, referring to fig. 3, since the braking delay time is set to be not 0 when it is determined that the running state of the current vehicle is not a decelerating state, it is understood that when the braking delay time is not 0, i.e., the host vehicle has not decelerated; calculating the expected relative distance from the beginning of the moment to the end of the braking delay time according to the speed and the speed change rate of the current vehicle and the target vehicle, judging whether the expected relative distance is larger than the safety distance or not when the braking delay time is ended, and braking according to the maximum deceleration executable by a brake actuator to avoid collision accidents if the expected relative distance is smaller than the safety distance when the braking delay time is ended; if not less than, decel is obtained t1 As the current demanded deceleration of the vehicle, according to decel t1 And sending a corresponding second deceleration instruction to a brake actuator of the current vehicle, and further ensuring the riding experience of a driver and passengers on the premise of ensuring safe braking.
In the present embodiment, preferably, when the brake delay time is 0 and the current deceleration of the current vehicle is incremented, the deceleration value corresponding to the deceleration instruction of the previous cycle is taken as the initial deceleration, and the incremented deceleration is calculated from the initial deceleration;
Calculating second estimated travel distances of the current vehicle and the target vehicle according to the incremental deceleration, and calculating an estimated relative distance between the current vehicle and the target vehicle according to the second estimated travel distances of the current vehicle and the target vehicle; wherein the predicted relative distance is a second predicted relative distance;
wherein the incremental deceleration is calculated from the initial deceleration according to:
decelt 1 ＝min(decel t0 +b，decel max /2)
in the formula, decel t1 To increase the deceleration, decel t0 For initial deceleration, decel max Maximum deceleration that is executable for a brake actuator of a current vehicle; b is the increment, when decel t0 When=0, let b=excel max 2, when decel t0 When not equal to 0, let
Figure BDA0002882806990000161
Wherein m is an integer, j is the deceleration rate; when the current deceleration of the current vehicle is smaller than the initial deceleration decel t0 When j is>0; when the current deceleration of the current vehicle is equal to the initial deceleration decel t0 When j=0; when the current deceleration of the current vehicle is greater than the initial deceleration decel t0 When j is<0；
The second estimated travel distance of the current vehicle during deceleration ramp up is calculated by:
Figure BDA0002882806990000162
a second estimated travel distance of the target vehicle during deceleration incrementing is calculated by:
Figure BDA0002882806990000163
a second expected relative distance between the current vehicle and the target vehicle is calculated by:
S rel_2 ＝S to2 －S sv2 +S rel
Wherein a is sv1 T is the current speed change rate of the current vehicle delay For braking delay time, t 2 Time is increased for deceleration, and
Figure BDA0002882806990000164
S sv2 for a second estimated distance travelled by the current vehicle, S to2 For a second expected travel distance of the target vehicle S rel_2 For the current vehicleAnd a second expected relative distance between the target vehicles.
For example, referring to fig. 3, since the brake delay time is set to 0 when it is determined that the running state of the current vehicle is the decelerating state, it is understood that when the brake delay time is 0, i.e., the host vehicle is already in the decelerating state; at this time, assume an incremental deceleration decel t1 Let the increment deceleration decel t1 The value is the sum of the initial deceleration and the increment, and if the sum of the initial deceleration and the increment is greater than half of the maximum deceleration which can be executed by the brake actuator of the current vehicle, the value is half of the maximum deceleration which can be executed by the brake actuator of the current vehicle. From the following components
Figure BDA0002882806990000165
It can be seen that t 2 During this period, i.e., the deceleration rising period, the deceleration change rate j may be valued according to the actual test result of the vehicle. When t is acquired 2 After the predicted relative distance in the deceleration rising period, judging whether the predicted relative distance is larger than the safe distance at the end of the deceleration rising period, and if smaller than the safe distance, describing t 2 The deceleration during the braking is insufficient to ensure that no collision accident occurs after the vehicle is braked, so that the braking is performed according to the maximum deceleration executable by the brake actuator to avoid the collision accident, and if the deceleration is not smaller than the maximum deceleration, the decel is determined t1 As the current demanded deceleration of the vehicle, according to decel t1 And sending a corresponding second deceleration instruction to a brake actuator of the current vehicle, and further ensuring the riding experience of a driver and passengers on the premise of ensuring safe braking.
In this embodiment, preferably, the method further includes:
when the braking delay time is 0 and the deceleration change rate is 0, respectively calculating third running distances of the current vehicle and the target vehicle according to the incremental deceleration, and calculating the predicted relative distance between the current vehicle and the target vehicle according to the third predicted running distances of the current vehicle and the target vehicle; wherein the predicted relative distance is a third predicted relative distance;
wherein the third estimated travel distance of the current vehicle is calculated by:
Figure BDA0002882806990000171
a third estimated travel distance of the target vehicle is calculated by:
Figure BDA0002882806990000172
the travel time of the current vehicle at the incremental deceleration is calculated by:
Figure BDA0002882806990000173
a third expected relative distance between the current vehicle and the target vehicle is calculated by:
S rel_3 ＝S to3 －S sv3 +S rel
Wherein t is 3 For the current travel time of the vehicle at an increasing deceleration, S sv3 For a third expected travel distance of the current vehicle, S to3 For a third expected travel distance of the target vehicle, S rel_3 A third expected relative distance between the current vehicle and the target vehicle.
Exemplary, referring to FIG. 3, if t 2 The predicted relative distance predicted at the end of the period is still not less than the safe distance, indicating that the vehicle is stabilized at decel at this deceleration t1 Can avoid collision accidents during the period of time; t is t 3 After the period is completed, the deceleration of the current vehicle reaches the incremental deceleration decel t1 Entering a deceleration stabilization period at this time; calculating decel t1 The running time of the vehicle under deceleration is obtained, and the running time t of the current vehicle under the progressive deceleration is obtained 3 The following predicted relative distance, and then determine t 3 If the predicted relative distance is greater than the safe distance, the stable deceleration is insufficient to ensure no collision accident after the vehicle is braked, and therefore, the vehicle is brakedThe maximum deceleration that can be executed by the brake to avoid collision accidents; if not less than, decel is obtained t1 As the current demanded deceleration of the vehicle, according to decel t1 And sending a corresponding second deceleration instruction to a brake actuator of the current vehicle, and further ensuring the riding experience of a driver and passengers on the premise of ensuring safe braking.
In the present embodiment, preferably, when the predicted relative distance is greater than the guard distance threshold, the incremental deceleration is taken as the required deceleration, and a corresponding deceleration instruction is transmitted to the brake actuator of the current vehicle according to the required deceleration.
In the present embodiment, it is preferable that the third collision time is obtained from the current running speeds of the current vehicle and the target vehicle;
wherein the third collision time is calculated by:
Figure BDA0002882806990000181
in TTC threshold_3 Is the third collision time.
Specifically, when the collision time is smaller than the third collision time, the maximum braking deceleration decel is used max Braking until the vehicle stops or reaches a brake deceleration limit; otherwise, maintaining the current braking deceleration; thus, the double limitation of the expected relative distance and the collision time is realized, and the comfort and the safety of drivers and other passengers and the timeliness and the safety of braking are ensured.
Further, if the current time to collision TTC satisfies the following equation, it is determined that a collision is imminent:
Figure BDA0002882806990000191
in the formula, a mode that the collision time takes the minimum value of 0.2s and the third collision time is adopted, so that the time limit of 0.2s is reserved for emergency braking, and the timeliness of braking is further improved. In the specific embodiment, 0.2s is only one preferable value provided in the present embodiment, and may be set to 0.3s, 0.35s, or the like according to the actual vehicle condition of the vehicle, and is not particularly limited herein.
In summary, in the embodiment of the invention, the running state of the vehicle is judged by the depth of the brake pedal and the pressure of the brake master cylinder together, so that the misjudgment of the braking state of a driver is avoided; under the condition that the vehicle is not in a driver braking state, the collision time of the current vehicle and the front vehicle, namely the target vehicle, is calculated, so that the braking condition can be timely obtained, and the safety and timeliness of automatic braking are improved; the first-stage open-loop braking is triggered when the collision time is not longer than the first collision time, and a corresponding first deceleration instruction is sent to a brake actuator of the current vehicle according to the current running speed of the current vehicle, so that the startle and the danger caused by excessively rapid deceleration or unnecessary emergency braking are avoided, the safety of the vehicle braking is improved, and the comfort level of a driver and other passengers can be improved; the second-level closed-loop control is triggered when the collision time is not longer than the second collision time, and the braking deceleration is calculated in real time according to the states of the current vehicle and the target vehicle, so that the decoupling of the first-level braking and the second-level braking is realized, the triggering time is not mutually contained, the braking deceleration is regulated according to the actual running condition of the vehicle, and the safety of the braking process is further improved; through judging the safe collision distance, when the predicted relative distance is still larger than the safe distance threshold value, the time for decelerating according to the vehicle speed is indicated to be still provided at present, and at the moment, the required deceleration of the current vehicle can be calculated according to the parameters such as the predicted relative distance, the vehicle speed of the current vehicle, the vehicle speed of the target vehicle and the like; when the vehicle is in a driver braking state, taking the braking behavior of the driver into consideration, and providing braking control assistance for the driver taking braking measures as little as possible in a low-speed scene; when a collision is imminent, the vehicle is braked to a stop by a maximum braking force, so that the safety braking is realized on the premise of ensuring the safety and comfort of drivers and other passengers.
Embodiment two:
referring to fig. 4, a schematic structural diagram of an automatic braking device for a vehicle according to an embodiment of the present invention includes:
a parameter calculation module 201 for calculating a collision time and an expected relative distance between the current vehicle and the target vehicle;
the state acquisition module 202 is configured to acquire a running state of a current vehicle, and determine whether the running state of the current vehicle is a driver braking state;
a brake control module 203 for:
when the first braking condition is met, a corresponding deceleration instruction is sent to a braking actuator of the current vehicle according to the current running speed of the current vehicle; the first braking condition comprises that the running state of the current vehicle is not a driver braking state and the collision time is not longer than the first collision time;
when the second braking condition is met, if the predicted relative distance is greater than the safe distance threshold, calculating the required deceleration of the current vehicle according to the predicted relative distance, sending a corresponding deceleration instruction to a brake actuator of the current vehicle according to the required deceleration, and if the predicted relative distance is not greater than the safe distance threshold, sending a corresponding deceleration instruction to the brake actuator of the current vehicle according to the maximum deceleration executable by the brake actuator of the current vehicle; wherein the second braking condition includes that the running state of the current vehicle is not a driver braking state and the collision time is not greater than the second collision time; the second collision time is less than the first collision time and greater than the third collision time;
And when the collision time is not more than the third collision time, sending a corresponding deceleration instruction to the brake actuator of the current vehicle according to the maximum executable deceleration of the brake actuator of the current vehicle.
Further, the method further comprises the following steps: when the current running state of the vehicle is the driver braking state, the following steps are performed:
judging whether the current running speed of the current vehicle is greater than a first running speed threshold value or not;
when the current running speed of the current vehicle is not greater than the first running speed threshold value and the predicted relative distance is greater than the safe distance threshold value, not braking;
when the current running speed of the current vehicle is greater than the first running speed threshold, the collision time is not greater than the second collision time, and the predicted relative distance is greater than the safe distance threshold, the required deceleration of the current vehicle is calculated according to the predicted relative distance, and a corresponding deceleration instruction is sent to a brake actuator of the current vehicle according to the required deceleration.
Further, calculating a collision time of the current vehicle with the target vehicle includes:
acquiring the current running speed of the current vehicle, and acquiring the current running speed of the target vehicle and the running state of the target vehicle;
when the current running speed of the current vehicle is greater than the current running speed of the target vehicle and the running state of the target vehicle is a decelerating state, the collision time is calculated by:
Figure BDA0002882806990000211
When the current running speed of the current vehicle is greater than the current running speed of the target vehicle and the running state of the target vehicle is not a decelerating state, the collision time is calculated by:
Figure BDA0002882806990000212
when the current running speed of the current vehicle is not greater than the current running speed of the target vehicle, enabling the collision time to be TTC';
in the formula, v sv1 V is the current running speed of the current vehicle to1 For the current running speed of the target vehicle S rel A is the current expected relative distance between the current vehicle and the target vehicle to1 The TTC' is a preset collision time calibration value for the current speed change rate of the target vehicle.
Further, when the second braking condition is satisfied, further comprising:
acquiring the current deceleration of the current vehicle;
when the current speed change rate of the current vehicle is smaller than a preset deceleration state threshold value, judging that the running state of the current vehicle is a deceleration state, and setting the brake delay time of a brake actuator of the current vehicle to be 0;
when the current speed change rate of the current vehicle is not smaller than a preset deceleration state threshold value, judging that the running state of the current vehicle is not a deceleration state, and setting the braking delay time of a braking actuator of the current vehicle, wherein the braking delay time is not 0;
When the braking delay time is not 0, respectively calculating first estimated travel distances of the current vehicle and the target vehicle, and calculating an estimated relative distance between the current vehicle and the target vehicle according to the first estimated travel distances of the current vehicle and the target vehicle; wherein the predicted relative distance is a first predicted relative distance;
wherein the first estimated travel distance of the current vehicle is calculated by:
Figure BDA0002882806990000221
a first estimated travel distance of the target vehicle is calculated by:
Figure BDA0002882806990000222
the first expected relative distance is calculated by:
S rel_1 ＝S to1 －S sv1 +S rel
wherein a is sv1 T is the current speed change rate of the current vehicle delay For braking delay time, S sv1 For a first estimated distance travelled by the current vehicle S to1 For a first expected travel distance of the target vehicle S rel_1 Is a first expected relative distance between the current vehicle and the target vehicle.
Further, when the brake delay time is 0 and the current deceleration of the current vehicle is increased, taking the deceleration value corresponding to the deceleration instruction of the previous period as the initial deceleration, and calculating the increased deceleration according to the initial deceleration;
calculating second estimated travel distances of the current vehicle and the target vehicle according to the incremental deceleration, and calculating an estimated relative distance between the current vehicle and the target vehicle according to the second estimated travel distances of the current vehicle and the target vehicle; wherein the predicted relative distance is a second predicted relative distance;
Wherein the incremental deceleration is calculated from the initial deceleration according to:
decelt 1 ＝min(decel t0 +b，decel max /2)
in the formula, decel t1 To increase the deceleration, decel t0 For initial deceleration, decel max Maximum deceleration that is executable for a brake actuator of a current vehicle; b is the increment, when decel t0 When=0, let b=excel max 2, when decel t0 When not equal to 0, let
Figure BDA0002882806990000231
Wherein m is an integer, j is the deceleration rate; when the current deceleration of the current vehicle is smaller than the initial deceleration decel t0 When j is>0; when the current deceleration of the current vehicle is equal to the initial deceleration decel t0 When j=0; when the current deceleration of the current vehicle is greater than the initial deceleration decel t0 When j is<0；
The second estimated travel distance of the current vehicle during deceleration ramp up is calculated by:
Figure BDA0002882806990000232
a second estimated travel distance of the target vehicle during deceleration incrementing is calculated by:
Figure BDA0002882806990000233
a second expected relative distance between the current vehicle and the target vehicle is calculated by:
S rel_2 ＝S to2 －S sv2 +S rel
wherein a is sv1 T is the current speed change rate of the current vehicle delay For braking delay time, t 2 Time is increased for deceleration, and
Figure BDA0002882806990000234
S sv2 for a second estimated distance travelled by the current vehicle, S to2 For a second expected travel distance of the target vehicle S rel_2 A second expected relative distance between the current vehicle and the target vehicle.
Further, when the braking delay time is 0 and the deceleration change rate is 0, calculating third running distances of the current vehicle and the target vehicle according to the incremental deceleration, respectively, and calculating an estimated relative distance between the current vehicle and the target vehicle according to the third estimated running distances of the current vehicle and the target vehicle; wherein the predicted relative distance is a third predicted relative distance;
wherein the third estimated travel distance of the current vehicle is calculated by:
Figure BDA0002882806990000241
a third estimated travel distance of the target vehicle is calculated by:
Figure BDA0002882806990000242
the travel time of the current vehicle at the incremental deceleration is calculated by:
Figure BDA0002882806990000243
a third expected relative distance between the current vehicle and the target vehicle is calculated by:
S rel_3 ＝S to3 －S sv3 +S rel
wherein t is 3 For the current travel time of the vehicle at an increasing deceleration, S sv3 For a third expected travel distance of the current vehicle, S to3 For a third expected travel distance of the target vehicle, S rel_3 A third expected relative distance between the current vehicle and the target vehicle.
Further, the method further comprises the following steps:
when the predicted relative distance is greater than the safe distance threshold, the incremental deceleration is taken as the required deceleration, and a corresponding deceleration instruction is sent to a brake actuator of the current vehicle according to the required deceleration.
Further, the third collision time is obtained according to the current running speeds of the current vehicle and the target vehicle;
wherein the third collision time is calculated by:
Figure BDA0002882806990000244
in TTC threshold_3 Is the third collision time.
In summary, in the embodiment of the invention, the running state of the vehicle is judged by the depth of the brake pedal and the pressure of the brake master cylinder together, so that the misjudgment of the braking state of a driver is avoided; under the condition that the vehicle is not in a driver braking state, the collision time of the current vehicle and the front vehicle, namely the target vehicle, is calculated, so that the braking condition can be timely obtained, and the safety and timeliness of automatic braking are improved; the first-stage open-loop braking is triggered when the collision time is not longer than the first collision time, and a corresponding first deceleration instruction is sent to a brake actuator of the current vehicle according to the current running speed of the current vehicle, so that the startle and the danger caused by excessively rapid deceleration or unnecessary emergency braking are avoided, the safety of the vehicle braking is improved, and the comfort level of a driver and other passengers can be improved; the second-level closed-loop control is triggered when the collision time is not longer than the second collision time, and the braking deceleration is calculated in real time according to the states of the current vehicle and the target vehicle, so that the decoupling of the first-level braking and the second-level braking is realized, the triggering time is not mutually contained, the braking deceleration is regulated according to the actual running condition of the vehicle, and the safety of the braking process is further improved; through judging the safe collision distance, when the predicted relative distance is still larger than the safe distance threshold value, the time for decelerating according to the vehicle speed is indicated to be still provided at present, and at the moment, the required deceleration of the current vehicle can be calculated according to the parameters such as the predicted relative distance, the vehicle speed of the current vehicle, the vehicle speed of the target vehicle and the like; when the vehicle is in a driver braking state, taking the braking behavior of the driver into consideration, and providing braking control assistance for the driver taking braking measures as little as possible in a low-speed scene; when a collision is imminent, the vehicle is braked to a stop by a maximum braking force, so that the safety braking is realized on the premise of ensuring the safety and comfort of drivers and other passengers.
Embodiment III:
referring to fig. 5, a schematic diagram of a control system of an autopilot vehicle according to an embodiment of the present invention is shown. The control system of the autonomous vehicle of this embodiment includes: a processor 1, a memory 2 and a computer program stored in said memory 2 and executable on said processor, such as an automatic braking program of a vehicle. The steps of the above-described embodiments of the automatic braking method of each vehicle are implemented when the processor 1 executes the computer program. Alternatively, the processor 1 may implement the functions of the modules/units in the above-described embodiments of the apparatus when executing the computer program.
The computer program may be divided into one or more modules/units, which are stored in the memory and executed by the processor to accomplish the present invention, for example. The one or more modules/units may be a series of computer program instruction segments capable of performing a specific function for describing the execution of the computer program in an automatic braking device of the vehicle.
The control system of the autonomous vehicle may include, but is not limited to, a processor, a memory. It will be appreciated by those skilled in the art that the schematic diagram is merely an example of the control system of the autonomous vehicle and is not limiting of the control system of the autonomous vehicle, and may include more or fewer components than shown, or may combine certain components, or different components, e.g., the control system of the autonomous vehicle may further include input and output devices, network access devices, CAN buses, etc.
The processor may be a central processing unit (Central Processing Unit, CPU), other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. The general purpose processor may be a microprocessor or the processor may be any conventional processor or the like that is a control center of the control system of the autonomous vehicle, connecting various parts of the control system of the entire autonomous vehicle using various interfaces and lines.
The memory may be used to store the computer program and/or modules, and the processor may implement various functions of the control system of the autonomous vehicle by running or executing the computer program and/or modules stored in the memory and invoking data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program (such as a sound playing function, an image playing function, etc.) required for at least one function, and the like; the storage data area may store data (such as audio data, phonebook, etc.) created according to the use of the handset, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, memory, plug-in hard disk, smart Media Card (SMC), secure Digital (SD) Card, flash Card (Flash Card), at least one disk storage device, flash memory device, or other volatile solid-state storage device.
Wherein the modules/units of the vehicle's automatic braking device/control system integration, if implemented in the form of software functional units and sold or used as separate products, may be stored in a computer readable storage medium. Based on such understanding, the present invention may implement all or part of the flow of the method of the above embodiment, or may be implemented by a computer program to instruct related hardware, where the computer program may be stored in a computer readable storage medium, and when the computer program is executed by a processor, the computer program may implement the steps of each of the method embodiments described above. Wherein the computer program comprises computer program code which may be in source code form, object code form, executable file or some intermediate form etc. The computer readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer Memory, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), an electrical carrier signal, a telecommunications signal, a software distribution medium, and so forth. It should be noted that the computer readable medium contains content that can be appropriately scaled according to the requirements of jurisdictions in which such content is subject to legislation and patent practice, such as in certain jurisdictions in which such content is subject to legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunication signals.
It should be noted that the above-described apparatus embodiments are merely illustrative, and the units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the drawings of the embodiment of the device provided by the invention, the connection relation between the modules represents that the modules have communication connection, and can be specifically implemented as one or more communication buses or signal lines. Those of ordinary skill in the art will understand and implement the present invention without undue burden.
While the foregoing is directed to the preferred embodiments of the present invention, it will be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles of the invention, such changes and modifications are also intended to be within the scope of the invention.

Claims (11)

1. An automatic braking method of a vehicle, characterized by comprising:
Calculating the collision time and the expected relative distance between the current vehicle and the target vehicle;
acquiring the running state of a current vehicle, and judging whether the running state of the current vehicle is a driver braking state or not;
when a first braking condition is met, a corresponding deceleration instruction is sent to a braking actuator of the current vehicle according to the current running speed of the current vehicle; wherein the first braking condition includes that the running state of the current vehicle is not a driver braking state and the collision time is not greater than a first collision time;
when a second braking condition is met, if the expected relative distance is greater than a safe distance threshold, calculating the required deceleration of the current vehicle according to the expected relative distance, sending a corresponding deceleration instruction to a braking actuator of the current vehicle according to the required deceleration, and if the expected relative distance is not greater than the safe distance threshold, sending a corresponding deceleration instruction to the braking actuator of the current vehicle according to the maximum executable deceleration of the braking actuator of the current vehicle; wherein the second braking condition includes that the running state of the current vehicle is not a driver braking state and the collision time is not greater than a second collision time; the second collision time is less than the first collision time and greater than a third collision time;
And when the collision time is not more than the third collision time, sending a corresponding deceleration instruction to the brake actuator of the current vehicle according to the maximum executable deceleration of the brake actuator of the current vehicle.
2. The automatic braking method of a vehicle according to claim 1, characterized by further comprising: when the running state of the current vehicle is a driver braking state, executing the following steps:
judging whether the current running speed of the current vehicle is greater than a first running speed threshold value or not;
when the current running speed of the current vehicle is not greater than a first running speed threshold value and the predicted relative distance is greater than a safe distance threshold value, not braking;
when the current running speed of the current vehicle is greater than a first running speed threshold, the collision time is not greater than a second collision time, and the expected relative distance is greater than a safety distance threshold, calculating the required deceleration of the current vehicle according to the expected relative distance, and sending a corresponding deceleration instruction to a brake actuator of the current vehicle according to the required deceleration.
3. The automatic braking method of a vehicle according to claim 1, characterized in that the calculating of the collision time of the current vehicle with the target vehicle includes:
Acquiring the current running speed of the current vehicle, and acquiring the current running speed of the target vehicle and the running state of the target vehicle;
when the current running speed of the current vehicle is greater than the current running speed of the target vehicle and the running state of the target vehicle is a decelerating state, the collision time is calculated by the following equation:
Figure FDA0004044483020000021
when the current running speed of the current vehicle is greater than the current running speed of the target vehicle and the running state of the target vehicle is not a decelerating state, the collision time is calculated by:
Figure FDA0004044483020000022
when the current running speed of the current vehicle is not greater than the current running speed of the target vehicle, enabling the collision time to be TTC';
in the formula, v sv1 V, the current running speed of the current vehicle to1 For the current running speed of the target vehicle, S rel A, for a current expected relative distance between the current vehicle and the target vehicle to1 And TTC' is a preset collision time calibration value for the current speed change rate of the target vehicle.
4. The automatic braking method of a vehicle according to claim 3, characterized by further comprising, when the second braking condition is satisfied:
Acquiring the current deceleration of the current vehicle;
when the current speed change rate of the current vehicle is smaller than a preset deceleration state threshold value, judging that the running state of the current vehicle is a deceleration state, and setting the brake delay time of a brake actuator of the current vehicle to be 0;
when the current speed change rate of the current vehicle is not smaller than a preset deceleration state threshold value, judging that the running state of the current vehicle is not a deceleration state, and setting the braking delay time of a braking actuator of the current vehicle, wherein the braking delay time is not 0;
when the braking delay time is not 0, respectively calculating first expected running distances of the current vehicle and the target vehicle, and calculating an expected relative distance between the current vehicle and the target vehicle according to the first expected running distances of the current vehicle and the target vehicle; wherein the predicted relative distance is a first predicted relative distance;
wherein the first estimated travel distance of the current vehicle is calculated by:
Figure FDA0004044483020000031
calculating a first estimated travel distance of the target vehicle by:
Figure FDA0004044483020000032
the first expected relative distance is calculated by:
S rel_1 ＝S to1 －S sv1 +S rel
Wherein a is sv1 T is the current speed change rate of the current vehicle delay For the braking delay time, S sv1 For a first expected travel distance of the current vehicle, S to1 For a first expected travel distance of the target vehicle, S rel_1 Is a first expected relative distance between the current vehicle and the target vehicle.
5. The automatic braking method of a vehicle according to claim 4, characterized by further comprising:
when the braking delay time is 0 and the current deceleration of the current vehicle increases, taking a deceleration value corresponding to a deceleration instruction of the previous period as an initial deceleration, and calculating an increasing deceleration according to the initial deceleration;
calculating a second estimated travel distance of the current vehicle and the target vehicle, respectively, based on the incremental deceleration, and calculating an estimated relative distance between the current vehicle and the target vehicle based on the second estimated travel distance of the current vehicle and the target vehicle; wherein the predicted relative distance is a second predicted relative distance;
wherein the incremental deceleration is calculated from the initial deceleration according to:
decelt 1 ＝min(decel t0 +b，decel max /2)
in the formula, decel t1 For delivery ofSpeed increase and decrease, decel t0 For initial deceleration, decel max A maximum deceleration that is executable for a brake actuator of the current vehicle; b is the increment, when decel t0 When=0, let b=excel max 2, when decel t0 When not equal to 0, let
Figure FDA0004044483020000041
Wherein m is an integer, j is the deceleration rate; when the current deceleration of the current vehicle is smaller than the initial deceleration decel t0 When j is>0; when the current deceleration of the current vehicle is equal to the initial deceleration decel t0 When j=0; when the current deceleration of the current vehicle is greater than the initial deceleration decel t0 When j is<0；
A second estimated travel distance of the current vehicle during deceleration ramp up is calculated by:
Figure FDA0004044483020000042
a second estimated travel distance of the target vehicle during deceleration ramp up is calculated by:
Figure FDA0004044483020000043
calculating a second predicted relative distance between the current vehicle and the target vehicle by:
S rel_2 ＝S to2 －S sv2 +S rel
wherein a is sv1 T is the current speed change rate of the current vehicle delay For the braking delay time, t 2 Time is increased for deceleration, and
Figure FDA0004044483020000051
S sv2 for a second expected distance of travel of the current vehicle, S to2 For a second expected travel distance of the target vehicle, S rel_2 A second expected relative distance between the current vehicle and the target vehicle.
6. The automatic braking method of a vehicle according to claim 5, characterized by further comprising:
when the braking delay time is 0 and the deceleration change rate is 0, calculating third running distances of the current vehicle and the target vehicle according to the incremental deceleration, and calculating an estimated relative distance between the current vehicle and the target vehicle according to the third estimated running distances of the current vehicle and the target vehicle, respectively; wherein the predicted relative distance is a third predicted relative distance;
wherein the third estimated travel distance of the current vehicle is calculated by:
Figure FDA0004044483020000052
a third estimated travel distance of the target vehicle is calculated by:
Figure FDA0004044483020000053
calculating the travel time of the current vehicle at the incremental deceleration by:
Figure FDA0004044483020000054
calculating a third expected relative distance between the current vehicle and the target vehicle by:
S rel_3 ＝S to3 －S sv3 +S rel
wherein t is 3 For the travel time of the current vehicle at the incremental deceleration, S sv3 For a third expected travel distance of the current vehicle, S to3 For a third expected travel distance of the target vehicle, S rel_3 A third expected relative distance between the current vehicle and the target vehicle.
7. The automatic braking method of a vehicle according to any one of claims 5 to 6, characterized by further comprising:
and when the predicted relative distance is greater than a safe distance threshold, taking the incremental deceleration as the required deceleration, and sending a corresponding deceleration instruction to a brake actuator of the current vehicle according to the required deceleration.
8. The automatic braking method of a vehicle according to claim 1, characterized in that the third collision time is obtained from a current running speed of the current vehicle and the target vehicle;
wherein the third collision time is calculated by:
Figure FDA0004044483020000061
in TTC threshold_3 And the third collision time.
9. An automatic braking device for a vehicle, comprising:
the parameter calculation module is used for calculating the collision time and the expected relative distance between the current vehicle and the target vehicle;
the state acquisition module is used for acquiring the running state of the current vehicle and judging whether the running state of the current vehicle is a driver braking state or not;
a brake control module for:
when a first braking condition is met, a corresponding deceleration instruction is sent to a braking actuator of the current vehicle according to the current running speed of the current vehicle; wherein the first braking condition includes that the running state of the current vehicle is not a driver braking state and the collision time is not greater than a first collision time;
When a second braking condition is met, if the expected relative distance is greater than a safe distance threshold, calculating the required deceleration of the current vehicle according to the expected relative distance, sending a corresponding deceleration instruction to a braking actuator of the current vehicle according to the required deceleration, and if the expected relative distance is not greater than the safe distance threshold, sending a corresponding deceleration instruction to the braking actuator of the current vehicle according to the maximum executable deceleration of the braking actuator of the current vehicle; wherein the second braking condition includes that the running state of the current vehicle is not a driver braking state and the collision time is not greater than a second collision time; the second collision time is less than the first collision time and greater than a third collision time;
and when the collision time is not more than the third collision time, sending a corresponding deceleration instruction to the brake actuator of the current vehicle according to the maximum executable deceleration of the brake actuator of the current vehicle.
10. A control system for an autonomous vehicle, comprising a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, the processor implementing the method for automatically braking a vehicle according to any one of claims 1 to 8 when the computer program is executed.
11. A computer readable storage medium, characterized in that the computer readable storage medium comprises a stored computer program, wherein the computer program, when run, controls a device in which the computer readable storage medium is located to perform the automatic braking method of a vehicle according to any one of claims 1 to 8.
CN202110004846.2A 2021-01-04 2021-01-04 Automatic braking method, device and system for vehicle and storage medium Active CN114715087B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202110004846.2A CN114715087B (en) 2021-01-04 2021-01-04 Automatic braking method, device and system for vehicle and storage medium

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202110004846.2A CN114715087B (en) 2021-01-04 2021-01-04 Automatic braking method, device and system for vehicle and storage medium

Publications (2)

Publication Number Publication Date
CN114715087A CN114715087A (en) 2022-07-08
CN114715087B true CN114715087B (en) 2023-05-09

Family

ID=82234752

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110004846.2A Active CN114715087B (en) 2021-01-04 2021-01-04 Automatic braking method, device and system for vehicle and storage medium

Country Status (1)

Country Link
CN (1) CN114715087B (en)

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6809331B2 (en) * 2017-03-28 2021-01-06 トヨタ自動車株式会社 Vehicle control device
CN108569287B (en) * 2017-12-15 2021-02-09 蔚来(安徽)控股有限公司 Method and device for generating vehicle control command, vehicle controller and storage medium
CN111332264B (en) * 2020-03-18 2021-04-27 东风汽车集团有限公司 Automatic emergency braking control method and system
CN111688652B (en) * 2020-06-11 2021-04-27 奇瑞汽车股份有限公司 Braking method, device and storage medium for automatic emergency braking system
CN112046472A (en) * 2020-09-11 2020-12-08 中国第一汽车股份有限公司 Vehicle collision avoidance method and device, vehicle and storage medium

Also Published As

Publication number Publication date
CN114715087A (en) 2022-07-08

Similar Documents

Publication Publication Date Title
US20220055617A1 (en) Vehicle control device and control method
CN113104007A (en) Driving support device
CN112292299A (en) Method and control unit for operating a vehicle
WO2014178264A1 (en) Vehicle control device and vehicle control method
EP3473507A1 (en) Vehicle control device
CN111497831A (en) Pre-collision control device
CN114715087B (en) Automatic braking method, device and system for vehicle and storage medium
US20220118981A1 (en) Driver assistance device
CN105383459A (en) Automatic emergency brake method and device
EP1437254A1 (en) An adaptive cruise control system for a motor vehicle
US11958478B2 (en) Method for automatically avoiding or mitigating collision, and control system, storage medium and motor vehicle
WO2019188142A1 (en) Travel control device
CN112937561A (en) Vehicle brake assist device
US20240025406A1 (en) Method for adjusting speed of instant vehicle and device for adjusting speed of instant vehicle
US11999333B2 (en) Driving support device, driving support method, and storage medium
US20220118957A1 (en) Control device for vehicle, actuator system, control method, non-transitory storage medium, and vehicle
US20230219414A1 (en) Vehicle control device, vehicle control method, and non-transitory storage medium on which a program is stored
US20220297671A1 (en) Driver assistance device, driver assistance method, and non-transitory computer-readable storage medium storing program
US20240010197A1 (en) Method and device for regulating the speed of an autonomous vehicle
US20220063635A1 (en) Vehicle controller and headway distance control method using the same
JP7343840B2 (en) Vehicle control device
CN115071700A (en) Emergency braking control method, device, equipment and readable storage medium
JP3951970B2 (en) Vehicle travel control device
CN115140031A (en) Automatic driving method and device and electronic equipment
KR100921107B1 (en) Adaptive cruise control system and method

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant