CN115635958B - Vehicle driving assisting method and device - Google Patents
Vehicle driving assisting method and device Download PDFInfo
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- CN115635958B CN115635958B CN202211652184.0A CN202211652184A CN115635958B CN 115635958 B CN115635958 B CN 115635958B CN 202211652184 A CN202211652184 A CN 202211652184A CN 115635958 B CN115635958 B CN 115635958B
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Abstract
The application relates to a vehicle auxiliary driving method and a device, which determine the maximum deceleration which can be achieved by a vehicle on a road according to the friction coefficient and the inclination angle of the road; acquiring the required deceleration of the vehicle for avoiding collision with the target object in real time, and determining the latest braking point according to the required deceleration and the maximum deceleration; and/or acquiring the maximum lateral acceleration and the maximum steering wheel corner speed which can be reached when the vehicle runs; according to the motion track information of the vehicle, the position information of the target object and the first parameter, the required lateral acceleration and the required steering wheel turning speed of the vehicle for avoiding collision with the target object are determined, and the latest steering point is determined according to the required lateral acceleration and the maximum lateral acceleration, or the latest steering point is determined according to the required steering wheel turning speed and the maximum steering wheel turning speed, so that the problem of inaccurate judgment of the collision point in the related technology is solved.
Description
Technical Field
The application relates to the field of vehicle auxiliary driving, in particular to a vehicle auxiliary driving method and device.
Background
In the related art, vehicle driving assist systems generally avoid a collision using a longitudinal and a lateral manner. The longitudinal collision avoidance system is provided with an automatic emergency braking AEB system, the basic principle of the system is that a sensor is utilized to sense a moving target, a static target, a motorcycle, a bicycle, a pedestrian and the like in front of a vehicle, and when the system judges that collision danger exists, the longitudinal movement (a braking system and a power system) of the vehicle is controlled to decelerate or brake the vehicle so as to achieve the purpose of avoiding collision or lightening collision; the transverse collision avoidance system comprises an automatic emergency steering AES system and an emergency steering auxiliary system EMA system, and the basic principle is that a sensor is used for sensing a moving target, a static target, a motorcycle, a bicycle, a pedestrian and the like in front of a vehicle, and when the system judges that collision danger exists, the system assists a driver to steer to escape or automatically escape.
Whether the vehicle assisted driving system avoids a collision in the lateral direction or in the longitudinal direction. It is necessary to determine whether the vehicle cannot avoid collision by braking and turn to avoid collision, wherein a critical point when the vehicle cannot avoid collision by braking is a latest braking point, and a critical point when the vehicle cannot avoid collision by turning is a latest turning point. In the correlation technique, a fixed threshold is mostly set for the judgment of the latest braking point and the latest steering point, so that the anti-collision point cannot be matched with the actual driving condition, and the anti-collision point cannot be accurately determined.
At present, no effective solution is provided for the problem that the vehicle cannot accurately judge the anti-collision point in the related technology.
Disclosure of Invention
The embodiment of the application provides a vehicle driving assisting method and device, and aims to at least solve the problem that judgment of the latest braking point and the latest steering point of a vehicle is inaccurate in the related art.
In a first aspect, an embodiment of the present application provides a vehicle driving assistance method, including:
determining a friction coefficient of a road according to the type of the road on which a vehicle runs, acquiring an inclination angle of the road, and determining the maximum deceleration which can be achieved by the vehicle on the road according to the friction coefficient and the inclination angle; acquiring the required deceleration of the vehicle for avoiding collision with a target object in real time, and determining the latest braking point according to the required deceleration and the maximum deceleration; and/or the presence of a gas in the atmosphere,
acquiring the maximum lateral acceleration and the maximum steering wheel angular speed which can be reached when the vehicle runs; determining a required lateral acceleration and a required steering wheel angular velocity of the vehicle for avoiding collision with the target object according to the self motion track information of the vehicle, the position information of the target object and a first parameter, wherein the first parameter comprises the width of the vehicle, the width of the target object and a lateral safety distance between the vehicle and the target object; and determining a latest steering point according to the required lateral acceleration and the maximum lateral acceleration, or determining the latest steering point according to the required steering wheel turning speed and the maximum steering wheel turning speed.
In some of these embodiments, braking the vehicle comprises:
selecting a position point of the vehicle where the required deceleration is equal to the maximum deceleration as a latest braking point;
and under the condition that the current position of the vehicle does not exceed the latest braking point, the vehicle is braked to avoid collision.
In some of these embodiments, steering the vehicle comprises:
and selecting a position point where the required lateral acceleration is equal to the maximum lateral acceleration and/or the required steering wheel angular velocity is equal to the maximum steering wheel angular velocity as a latest steering point, judging whether the current position of the vehicle exceeds the latest steering point, and avoiding collision by adopting a mode of steering the vehicle under the condition that the current position of the vehicle does not exceed the latest steering point.
In some of these embodiments, determining the maximum deceleration achievable by the vehicle on the roadway comprises:
and acquiring the ratio of the load of the brake wheel to the total mass of the vehicle, and calculating the maximum deceleration according to the ratio of the load of the brake wheel to the total mass of the vehicle, the friction coefficient of the road, the inclination angle of the road and the gravity acceleration.
In some of these embodiments, obtaining in real-time a requested deceleration at which the vehicle avoids collision with a target object includes:
acquiring the longitudinal displacement of the vehicle running in preset time, wherein the preset time comprises the reaction time required by the driver to start the vehicle to decelerate:
acquiring the length of the vehicle and longitudinal position information of the target object;
and calculating the required deceleration according to the length of the vehicle, the running speed of the vehicle, the longitudinal position information of the target object and the longitudinal displacement.
In some of these embodiments, the longitudinal position information includes dynamic longitudinal position information, and calculating the required deceleration from the length of the vehicle, the traveling speed of the vehicle, the longitudinal position information of the target object, and the longitudinal displacement includes:
under the condition that the target object is in a motion state, sampling motion state information and the dynamic longitudinal position information of the target object within first sampling time;
predicting the demanded deceleration for a plurality of future units of time from the sampled data;
selecting a minimum value of the plurality of required decelerations as a target deceleration at which the vehicle avoids a collision with the target object.
In some of these embodiments, prior to determining the desired lateral acceleration and the desired steering wheel angular velocity for the vehicle to avoid a collision with the target object, the method further comprises:
and determining the lateral offset required by the vehicle for avoiding collision according to the self motion track information of the vehicle, the lateral position information of the target object and the fixed first parameter, wherein the motion track information comprises a position point of the vehicle in a second sampling time, the curvature of the motion track and the initial driving speed.
In some of these embodiments, after determining the amount of lateral offset required for the vehicle to avoid a collision, the method further comprises:
and calculating the required lateral acceleration required by the vehicle for avoiding collision according to the lateral offset, the initial driving speed and the second sampling time.
In some of these embodiments, after determining the amount of lateral offset required for the vehicle to avoid a collision, the method further comprises:
calculating an offset angle required by the vehicle for avoiding collision according to the transverse offset and the position point;
calculating a steering wheel rotation angle required by the vehicle for avoiding collision according to the deviation angle and a proportional coefficient of a steering wheel rotation angle and a wheel rotation angle;
and calculating the required steering wheel rotating speed required by the vehicle for avoiding collision according to the steering wheel rotating angle and the second sampling time.
In a second aspect, an embodiment of the present application provides a vehicle driving assistance device, including:
the system comprises a latest braking point determining module, a deceleration control module and a control module, wherein the latest braking point determining module is used for determining a friction coefficient of a road according to the road surface type of the road on which a vehicle runs, acquiring an inclination angle of the road, and determining the maximum deceleration which can be achieved by the vehicle on the road according to the friction coefficient and the inclination angle; acquiring the required deceleration of the vehicle for avoiding collision with a target object in real time, and determining the latest braking point according to the required deceleration and the maximum deceleration;
the latest steering point determining module is used for acquiring the maximum transverse acceleration and the maximum steering wheel turning speed which can be achieved when the vehicle runs; determining a required lateral acceleration and a required steering wheel angular velocity of the vehicle for avoiding collision with the target object according to the self motion track information of the vehicle, the lateral position information of the target object and a first parameter, wherein the first parameter comprises the width of the vehicle, the width of the target object and the lateral safety distance between the vehicle and the target object; and determining a latest steering point according to the required lateral acceleration and the maximum lateral acceleration, or determining the latest steering point according to the required steering wheel turning speed and the maximum steering wheel turning speed.
Compared with the related art, the vehicle driving assistance method provided by the embodiment of the application determines the friction coefficient of the road according to the road surface type of the road on which the vehicle runs, acquires the inclination angle of the road, and determines the maximum deceleration which can be achieved by the vehicle on the road according to the friction coefficient and the inclination angle; acquiring the required deceleration of the vehicle for avoiding collision with the target object in real time, and determining the latest braking point according to the required deceleration and the maximum deceleration; and/or acquiring the maximum lateral acceleration and the maximum steering wheel angular speed which can be reached when the vehicle runs; determining a required lateral acceleration and a required steering wheel angular velocity of the vehicle for avoiding collision with the target object according to the self motion track information of the vehicle, the position information of the target object and a first parameter, wherein the first parameter comprises the width of the vehicle, the width of the target object and the lateral safety distance between the vehicle and the target object; and determining the latest steering point according to the required lateral acceleration and the maximum lateral acceleration, or determining the latest steering point according to the required steering wheel turning speed and the maximum steering wheel turning speed. Through the method and the device, the problem that the judgment of the anti-collision point is inaccurate is solved, and the beneficial effect of accurately judging the anti-collision point is realized.
The details of one or more embodiments of the application are set forth in the accompanying drawings and the description below to provide a more thorough understanding of the application.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
fig. 1 is an application environment diagram of a vehicle driving assistance method according to an embodiment of the present application;
fig. 2 is a flowchart of a latest braking point determination of the vehicle assistant driving method according to the embodiment of the present application;
fig. 3 is a flowchart of the latest turning point determination of the vehicle assisted driving method of the embodiment of the present application;
fig. 4 is an exemplary diagram of the latest braking point and the latest steering point of the vehicle assistant driving method of the embodiment of the present application;
FIG. 5 is a schematic diagram illustrating the calculation of a required steering wheel angular velocity in the vehicle assisted driving method according to the embodiment of the present application;
fig. 6 is a schematic diagram of automatic vehicle steering in different scenarios of the vehicle-assisted driving method according to the embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be described and illustrated 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. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments provided in the present application without any inventive step are within the scope of protection of the present application.
It is obvious that the drawings in the following description are only examples or embodiments of the present application, and that it is also possible for a person skilled in the art to apply the present application to other similar contexts on the basis of these drawings without inventive effort. Moreover, it should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another.
Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the specification. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of ordinary skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments without conflict.
Unless defined otherwise, technical or scientific terms referred to herein shall have the ordinary meaning as understood by those of ordinary skill in the art to which this application belongs. Reference to "a," "an," "the," and similar words throughout this application are not to be construed as limiting in number, and may refer to the singular or the plural. The present application is directed to the use of the terms "including," "comprising," "having," and any variations thereof, which are intended to cover non-exclusive inclusions; for example, a process, method, system, article, or apparatus that comprises a list of steps or modules (elements) is not limited to the listed steps or elements, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus. The term "plurality" as referred to herein means two or more.
The vehicle driving assisting method and the vehicle driving assisting device can be applied to the application environment shown in fig. 1. Wherein the terminal 102 communicates with the server 104 via a network. The data storage system may store data that the server 104 needs to process. The data storage system may be integrated on the server 104 or may be placed on the cloud or other network server. The terminal 102 may be a vehicle control device, such as an automatic emergency steering AES system or an emergency steering assist system EMA system of a vehicle. The server 104 may be implemented by a separate server or a server cluster composed of a plurality of servers, the server 104 stores an algorithm for implementing vehicle driving assistance, and the terminal 102 may update the driving assistance function by downloading the algorithm from the server 104.
The vehicle driving assisting method provided by the present application will be described by the following three embodiments.
In one embodiment, a vehicle driving assist method is provided, and fig. 2 is a flowchart of a latest braking point determination of the vehicle driving assist method of the embodiment, as shown in fig. 2, the flowchart includes the following steps:
step S201, according to the road surface type of the road on which the vehicle runs, determining the friction coefficient of the road, acquiring the inclination angle of the road, and according to the friction coefficient and the inclination angle, determining the maximum deceleration which can be achieved by the vehicle on the road.
The maximum deceleration is the limit deceleration that the vehicle can reach during running, and the maximum deceleration is not only related to the preset parameters of the vehicle, but also influenced by the road environment. In the application, different friction coefficients are determined according to the type of the road on which the vehicle runs, such as asphalt, cement, gravel and the like, and the maximum deceleration which can be achieved by the vehicle running under the current environment is calculated in real time according to a kinematic formula by combining the inclination angle of the road on which the vehicle runs. The type of the driving road and the inclination angle of the vehicle can be obtained through GPS positioning, a sensor, a laser radar, and the like, which is not limited in the present application.
Step S202, acquiring the required deceleration of the vehicle for avoiding collision with the target object in real time, and determining the latest braking point according to the required deceleration and the maximum deceleration.
Since the required deceleration varies with the relative position of the vehicle and the target object, there is always a position point at which the vehicle cannot avoid a collision with the target object by braking, and this critical position point is the latest braking point.
Illustratively, the more the vehicle is closer to the target object, the greater the required deceleration of the vehicle to avoid collision with the target object. The relative position of the vehicle and the target object is influenced by the motion state of the vehicle and the target object, and when the collision risk with the target object is found, the driver does not brake the vehicle immediately but needs a certain reaction time, so after the collision risk with the front target object is judged, the vehicle can also do a constant-speed or accelerated motion within the reaction time of the driver. After the driver brakes, the vehicle performs deceleration movement, and the movement state of the target object is unknown and uncontrollable, so that the movement state of the target object needs to be sampled, and the future movement state of the target object needs to be predicted according to the sampling result.
In one embodiment, a vehicle driving assist method is provided, and fig. 3 is a flowchart of the latest turning point determination of the vehicle driving assist method of the embodiment, as shown in fig. 3, the flowchart includes the following steps:
in step S301, the maximum lateral acceleration and the maximum steering wheel angular velocity that can be achieved when the vehicle is traveling are acquired.
The maximum lateral acceleration and the maximum steering wheel angular speed which can be achieved when the vehicle runs are calibrated or set by default by a driver of the vehicle.
Step S302, determining a required lateral acceleration and a required steering wheel angular velocity of the vehicle for avoiding collision with the target object according to the self motion track information of the vehicle, the position information of the target object and a first parameter, wherein the first parameter comprises the width of the vehicle, the width of the target object and the lateral safe distance between the vehicle and the target object.
The motion trail information of the vehicle itself includes the running speed of the vehicle, the yaw rate of the vehicle, the position point of the motion trail and the curvature of the motion trail. The position information of the target object includes a lateral coordinate position point of the target object. The lateral safe distance between the vehicle and the target object refers to a lateral distance that the vehicle and the target object need to maintain in order not to collide. According to the self motion track information of the vehicle, the position information of the target object and the first parameter, calculating the offset and the offset angle required by the vehicle for avoiding collision, calculating the required transverse acceleration according to the offset, and calculating the required steering wheel turning speed according to the offset angle.
Step S303, determining the latest steering point according to the required lateral acceleration and the maximum lateral acceleration, or determining the latest steering point according to the required steering wheel turning speed and the maximum steering wheel turning speed.
Wherein, the position point satisfying one of the two conditions that the required lateral deceleration is smaller than the maximum lateral deceleration or the required steering wheel angular velocity is smaller than the maximum steering wheel angular velocity is the latest steering point.
In one embodiment, a vehicle assistant driving method is provided, and fig. 2 and 3 are flowcharts illustrating determination of a latest braking point and a latest steering point in the vehicle assistant driving method according to the embodiment, where the flowcharts include the following steps, as shown in fig. 2 and 3:
step S201, according to the road surface type of the road on which the vehicle runs, determining the friction coefficient of the road, acquiring the inclination angle of the road, and according to the friction coefficient and the inclination angle, determining the maximum deceleration which can be achieved by the vehicle on the road.
Step S202, acquiring the required deceleration of the vehicle for avoiding collision with the target object in real time, and determining the latest braking point according to the required deceleration and the maximum deceleration.
In step S301, the maximum lateral acceleration and the maximum steering wheel angular velocity that can be achieved when the vehicle is traveling are acquired.
Step S302, determining a required lateral acceleration and a required steering wheel angular velocity of the vehicle for avoiding collision with the target object according to the self motion track information of the vehicle, the position information of the target object and a first parameter, wherein the first parameter comprises the width of the vehicle, the width of the target object and the lateral safe distance between the vehicle and the target object.
Step S303, determining the latest steering point according to the required lateral acceleration and the maximum lateral acceleration, or determining the latest steering point according to the required steering wheel turning speed and the maximum steering wheel turning speed.
Fig. 4 is an exemplary diagram of the latest braking point and the latest turning point in the embodiment of the present application, and as shown in fig. 4, the H vehicle is the own vehicle, the T vehicle is the target object, and at the warning point, the vehicle detects the collision risk and issues an alarm. In fig. 4, the H vehicle is located at a point that has exceeded the latest braking point, and therefore cannot avoid a collision by braking; however, the vehicle H is not yet at the latest turning point, and thus the collision can be avoided by turning. At the automatic emergency steering point, the vehicle is steered and eventually successfully avoids a collision.
Research shows that in the related technology, only fixed parameters of a vehicle are considered in the calculation of the latest braking point and the latest steering point, and errors caused by environmental factors of a driving road of the vehicle and a future motion track of the vehicle are not considered, so that the problem that the judgment of the latest braking point and the latest steering point of the vehicle is inaccurate can be caused. In the method, the environmental factors of the vehicle running road and/or the error caused by the future motion track of the vehicle are taken into consideration of the judgment of the anti-collision point, so that the latest braking point and/or the latest turning point are accurately judged, the problem of inaccurate judgment of the anti-collision point is solved, and the beneficial effect of accurately judging the anti-collision point is realized. In some of these embodiments, braking the vehicle comprises: selecting a position point of the vehicle, at which the required deceleration is equal to the maximum deceleration, as a latest braking point; and under the condition that the current position of the vehicle does not exceed the latest braking point, the vehicle is braked to avoid collision.
Wherein the latest braking point, at which the required deceleration of the vehicle required to avoid a collision equals the maximum deceleration that the vehicle can achieve under the current road environment, is a critical point at which the vehicle can avoid a collision by braking. When the vehicle has not reached the latest braking point, the vehicle may be braked to avoid a collision, and the specific braking strategy is not limited in this application.
In some of these embodiments, steering the vehicle comprises: and selecting a position point with the required lateral acceleration equal to the maximum lateral acceleration and/or the required steering wheel angular speed equal to the maximum steering wheel angular speed as a latest steering point, judging whether the current position of the vehicle exceeds the latest steering point, and avoiding collision by adopting a vehicle steering mode under the condition that the current position of the vehicle does not exceed the latest steering point.
The vehicle can avoid the critical point of collision by steering at the latest steering point, the required lateral acceleration of the vehicle for avoiding collision is equal to the maximum lateral acceleration which can be reached by the vehicle at the latest steering point, or the required steering wheel corner speed of the vehicle for avoiding collision is equal to the maximum steering wheel corner speed which can be reached by the vehicle, and the latest steering point is the critical point when one of the two conditions is met. When the vehicle has not reached the latest turning point, the vehicle may be steered to avoid a collision, and the specific steering strategy is not limited in this application.
In some of these embodiments, determining the maximum deceleration achievable by the vehicle on the road comprises:
and acquiring the ratio of the load of the brake wheel to the total mass of the vehicle, and calculating the maximum deceleration according to the ratio of the load of the brake wheel to the total mass of the vehicle, the friction coefficient of the road, the inclination angle of the road and the gravity acceleration.
The maximum deceleration which can be achieved by the vehicle and the friction coefficient of the road where the vehicle is located are related to the inclination rate of the road, and the calculation formula of the maximum deceleration is as follows:
wherein the content of the first and second substances,kas the ratio of the brake wheel load to the total mass of the vehicle,μit is the coefficient of friction of the road,αis the angle of inclination of the road and,gis the acceleration of gravity. When the vehicle is running on an uphill slope, the calculation formulatan αTaking a positive number; when the vehicle is running downhill, in the calculation formulatan αTaking the negative sign.
In some of these embodiments, obtaining the required deceleration at which the vehicle avoids collision with the target object in real time includes: acquiring the longitudinal displacement of the vehicle running within preset time, wherein the preset time comprises the reaction time required by the driver of the vehicle to start the vehicle to decelerate: acquiring the length of a vehicle and longitudinal position information of a target object; and calculating the required deceleration according to the length of the vehicle, the running speed of the vehicle, the longitudinal position information and the longitudinal displacement of the target object.
Wherein the position point of the target object is taken
Wherein, in the step (A),
as a longitudinal position coordinate point of the vehicle,
is a lateral position coordinate point of the vehicle.
The reaction time from the discovery of the risk of collision by the driver of the vehicle to the start of braking the vehicle is preset to
And in the preset reaction time, the longitudinal displacement of the vehicle in running is as follows:
wherein the content of the first and second substances,
is the longitudinal displacement of the vehicle within a preset time,
for the initial travel speed of the vehicle at the time of the discovery of the risk of collision,
the running acceleration of the vehicle in the preset time is obtained.
Length of vehicle
The distance from the rear axle of the vehicle to the front bar is indicated, and when the front target object is in a static state, the longitudinal position information of the target object, namely a longitudinal position coordinate pointIs maintained as
Constant, at which time deceleration is demandedANegLgtReqThe calculation formula of (2) is as follows:
in some of these embodiments, the longitudinal position information includes dynamic longitudinal position information, and calculating the demanded deceleration based on the length of the vehicle, the travel speed of the vehicle, the longitudinal position information of the target object, and the longitudinal displacement includes:
under the condition that the target object is in a motion state, sampling motion state information and dynamic longitudinal position information of the target object within first sampling time;
predicting the demanded deceleration for a plurality of future units of time from the sampled data;
the minimum value of the plurality of required decelerations is selected as a target deceleration at which the vehicle avoids a collision with the target object.
When the target object at the front side is in a motion state, the longitudinal position information of the target object is dynamically changed along with the motion of the target object. Selecting first sampling time, sampling the motion states of a target object and the self-vehicle, dividing the sampling time period into a plurality of unit times, respectively calculating the required decelerations corresponding to the unit times, and selecting the deceleration with the minimum value as the required deceleration required by the longitudinal direction of the vehicle for avoiding collision, wherein the required deceleration at the momentANegLgtReqThe calculation formula of (2) is as follows:
wherein the content of the first and second substances,ANegLgtReq(i)slowing down the speed of the demand corresponding to a certain unit timeThe degree of the magnetic field is measured,
is the acceleration of the motion of the target object,
is the current speed of the movement of the target object,Tiis the unit time of sampling.
In some embodiments, before determining the required lateral acceleration and the required steering wheel angular velocity for avoiding the collision of the vehicle with the target object, the method further comprises:
and determining the lateral offset required by the vehicle to avoid collision according to the self motion track information of the vehicle, the position information of the target object and the first parameter, wherein the motion track information comprises the position point of the vehicle in the second sampling time, the curvature of the motion track and the initial running speed.
The position information of the target object comprises a current transverse position point, a current longitudinal position point and a longitudinal position point in the second sampling time of the target object. In a second sampling time, sampling the motion and position information of the target object, and calculating a longitudinal position point of the target object in the second sampling time, wherein a specific calculation formula is as follows:
wherein the content of the first and second substances,
is the longitudinal position point of the target object in the second sampling time,
is the current longitudinal position point of the target object,
the motion speed of the target object in the second sampling time,TTCis the second sample time.
According to the yaw velocity of the vehicle and the running speed of the vehicle, the curvature of the motion trail of the vehicle is calculated, and the specific calculation formula is as follows:
wherein the content of the first and second substances,Cis the curvature of the motion trajectory of the vehicle,yawrateis the yaw-rate of the vehicle,speedis the running speed of the vehicle.
After the curvature of the longitudinal position point of the target object and the vehicle motion track in the second sampling time is obtained, calculating the transverse offset required by the vehicle for avoiding collision, wherein the specific calculation formula is as follows:
wherein the content of the first and second substances,
the amount of lateral offset required for vehicle collision avoidance,
is a point at the lateral position of the target object,
is the width of the target object and,
in order to be the width of the vehicle itself,Cis the curvature of the motion trajectory of the vehicle,Crwhich is the differential of the curvature of the motion trajectory,
is the lateral safe distance of the vehicle from the target object.
In some embodiments, after determining the lateral offset required for avoiding the collision, the method further comprises:
and calculating the required lateral acceleration required by the vehicle to avoid the collision according to the lateral offset, the initial driving speed and the second sampling time.
Wherein the calculation formula of the required lateral acceleration required for avoiding the collision of the vehicle is:
wherein the content of the first and second substances,ALatReqthe required lateral acceleration required for the vehicle to avoid a collision,
the transverse speed of the self-vehicle at the current moment is shown.
In some embodiments, after determining the lateral offset required for avoiding the collision, the method further comprises:
calculating a deviation angle required by the vehicle for avoiding collision according to the transverse deviation amount and the position point; calculating a steering wheel rotation angle required by the vehicle for avoiding collision according to the deviation angle and a proportional coefficient of the steering wheel rotation angle and the wheel rotation angle; and calculating the required steering wheel rotating speed required by the vehicle for avoiding collision according to the steering wheel rotating angle and the second sampling time.
In which the offset angle required for avoiding a collision of the vehicle
The calculation formula of (2) is as follows:
after obtaining the offset angle required by the vehicle for avoiding collision, calculating the steering wheel rotation angle theta required by the vehicle for avoiding collision, wherein the specific calculation formula is as follows:
wherein the content of the first and second substances,
is the proportionality coefficient of the steering wheel angle and the wheel angle of the vehicle.
Obtaining the steering wheel rotation angle required by the vehicle collision avoidance according to the steering wheel rotation angle required by the vehicle collision avoidance and the second sampling timePinionAgSpdReqThe specific calculation formula is as follows:
for example, fig. 5 is a schematic diagram illustrating calculation of a required steering wheel angular velocity, as shown in fig. 5, an H vehicle is a self vehicle, a T vehicle is a target object, position changes of the self vehicle and the target object before and after steering are given, and a lateral offset of the self vehicle is
The offset angle is θ. The longitudinal position of the target object is also changed when the vehicle turns, and the longitudinal position point of the target object is the longitudinal position point when the vehicle turns
At the end of the steering of the vehicle, the longitudinal displacement of the target object is
At a longitudinal position of
。
Fig. 6 is a schematic diagram of automatic vehicle steering in different scenarios in the present application, including four different scenario examples of Case1 to Case 4:
example 1, the host vehicle recognizes that the preceding target object is a traveling vehicle, determines that there is a risk of collision with the preceding vehicle, and performs automatic steering to avoid the collision.
Example 2, the host vehicle recognizes that the target object in front is a Vulnerable Road User (VRU) including pedestrians and riders, determines that there is a risk of collision with the VRU in front, and performs automatic steering to avoid the collision.
Example 3, the host vehicle recognizes that the front target object is an unknown type object, determines that there is a risk of collision with the front unknown type object, and performs automatic steering to avoid collision.
Example 4, the vehicle recognizes that the front is an intersection, has no lane line, and has a collision risk with the front VRU, and performs automatic steering to avoid collision.
The embodiment of the present application further provides a vehicle driver assistance device, including:
the system comprises a latest braking point determining module, a deceleration control module and a control module, wherein the latest braking point determining module is used for determining a friction coefficient of a road according to the road surface type of the road on which a vehicle runs, acquiring an inclination angle of the road, and determining the maximum deceleration which can be achieved by the vehicle on the road according to the friction coefficient and the inclination angle; acquiring the required deceleration of the vehicle for avoiding collision with a target object in real time, and determining the latest braking point according to the required deceleration and the maximum deceleration;
the latest steering point determining module is used for acquiring the maximum transverse acceleration and the maximum steering wheel turning speed which can be achieved when the vehicle runs; determining a required lateral acceleration and a required steering wheel angular velocity of the vehicle for avoiding collision with the target object according to the self motion track information of the vehicle, the position information of the target object and a first parameter, wherein the first parameter comprises the width of the vehicle, the width of the target object and a lateral safety distance between the vehicle and the target object; and determining a latest steering point according to the required lateral acceleration and the maximum lateral acceleration, or determining the latest steering point according to the required steering wheel turning speed and the maximum steering wheel turning speed.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is specific and detailed, but not to be understood as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (8)
1. A vehicle driving assist method, characterized by comprising:
determining a friction coefficient of a road according to the road surface type of the road on which a vehicle runs, acquiring an inclination angle of the road, and determining the maximum deceleration which can be achieved by the vehicle on the road according to the friction coefficient and the inclination angle; acquiring the required deceleration of the vehicle for avoiding collision with a target object in real time, and determining the latest braking point according to the required deceleration and the maximum deceleration; and (c) and (d),
acquiring the maximum lateral acceleration and the maximum steering wheel angular speed which can be reached when the vehicle runs; determining a lateral offset required by the vehicle to avoid collision according to self motion track information of the vehicle, position information of the target object and a first parameter, and determining a required lateral acceleration and a required steering wheel turning speed for the vehicle to avoid collision with the target object, wherein the motion track information comprises a position point of the vehicle within a second sampling time, a curvature and an initial driving speed of a motion track, and the first parameter comprises a width of the vehicle, a width of the target object and a lateral safety distance between the vehicle and the target object; determining a latest steering point according to the required lateral acceleration and the maximum lateral acceleration, or determining the latest steering point according to the required steering wheel turning speed and the maximum steering wheel turning speed;
wherein steering the vehicle after determining the latest steering point comprises:
and selecting a position point where the required lateral acceleration is equal to the maximum lateral acceleration and/or the required steering wheel angular velocity is equal to the maximum steering wheel angular velocity as a latest steering point, judging whether the current position of the vehicle exceeds the latest steering point, and avoiding collision by adopting a mode of steering the vehicle under the condition that the current position of the vehicle does not exceed the latest steering point.
2. The vehicle-assisted driving method according to claim 1, characterized in that braking the vehicle includes:
selecting a position point of the vehicle where the required deceleration is equal to the maximum deceleration as a latest braking point;
and under the condition that the current position of the vehicle does not exceed the latest braking point, the vehicle is braked to avoid collision.
3. The vehicle-assisted driving method according to claim 1, characterized in that determining the maximum deceleration that the vehicle can achieve on the road includes:
and acquiring the ratio of the load of the brake wheel to the total mass of the vehicle, and calculating the maximum deceleration according to the ratio of the load of the brake wheel to the total mass of the vehicle, the friction coefficient of the road, the inclination angle of the road and the gravity acceleration.
4. The vehicle-assisted driving method according to claim 1, characterized in that acquiring, in real time, a required deceleration at which the vehicle avoids collision with a target object includes:
acquiring the longitudinal displacement of the vehicle running in preset time, wherein the preset time comprises the reaction time required by the driver to start the vehicle to decelerate:
acquiring the length of the vehicle and longitudinal position information of the target object;
and calculating the required deceleration according to the length of the vehicle, the running speed of the vehicle, the longitudinal position information of the target object and the longitudinal displacement.
5. The vehicle driving assist method according to claim 4, wherein the longitudinal position information includes dynamic longitudinal position information, and the calculating the required deceleration based on the length of the vehicle, the width of the target object, the running speed of the vehicle, the longitudinal position information of the target object, and the longitudinal displacement includes:
under the condition that the target object is in a motion state, sampling motion state information and the dynamic longitudinal position information of the target object within first sampling time;
predicting the demanded deceleration over a plurality of future units of time from sampled data;
selecting a minimum value of the plurality of required decelerations as a target deceleration at which the vehicle avoids a collision with the target object.
6. The vehicle-assisted driving method according to claim 1, characterized in that, after determining the amount of lateral offset required for the vehicle to avoid a collision, the method further comprises:
and calculating the required lateral acceleration required by the vehicle for avoiding collision according to the lateral offset, the initial driving speed and the second sampling time.
7. The vehicle-assisted driving method according to claim 1, characterized in that, after determining the amount of lateral offset required for the vehicle to avoid a collision, the method further comprises:
calculating an offset angle required by the vehicle for avoiding collision according to the transverse offset and the position point;
calculating a steering wheel rotation angle required by the vehicle for avoiding collision according to the deviation angle and a proportional coefficient of a steering wheel rotation angle and a wheel rotation angle;
and calculating the required steering wheel rotating speed required by the vehicle for avoiding collision according to the steering wheel rotating angle and the second sampling time.
8. A vehicle driving assist apparatus, characterized by comprising:
the system comprises a latest braking point determining module, a deceleration control module and a control module, wherein the latest braking point determining module is used for determining a friction coefficient of a road according to the road surface type of the road on which a vehicle runs, acquiring an inclination angle of the road, and determining the maximum deceleration which can be achieved by the vehicle on the road according to the friction coefficient and the inclination angle; acquiring the required deceleration of the vehicle for avoiding collision with a target object in real time, and determining the latest braking point according to the required deceleration and the maximum deceleration;
the latest steering point determining module is used for acquiring the maximum lateral acceleration and the maximum steering wheel corner speed which can be reached when the vehicle runs; determining a lateral offset required by the vehicle to avoid collision according to self motion track information of the vehicle, position information of the target object and a first parameter, and determining a required lateral acceleration and a required steering wheel turning speed for the vehicle to avoid collision with the target object, wherein the motion track information comprises a position point of the vehicle within a second sampling time, a curvature and an initial driving speed of a motion track, and the first parameter comprises a width of the vehicle, a width of the target object and a lateral safety distance between the vehicle and the target object; and determining a latest steering point according to the required lateral acceleration and the maximum lateral acceleration, or determining a latest steering point according to the required steering wheel angular velocity and the maximum steering wheel angular velocity, wherein after determining the latest steering point, steering the vehicle comprises: and selecting a position point where the required lateral acceleration is equal to the maximum lateral acceleration and/or the required steering wheel angular velocity is equal to the maximum steering wheel angular velocity as a latest steering point, judging whether the current position of the vehicle exceeds the latest steering point, and avoiding collision by adopting a mode of steering the vehicle under the condition that the current position of the vehicle does not exceed the latest steering point.
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| CN202211652184.0A CN115635958B (en) | 2022-12-22 | 2022-12-22 | Vehicle driving assisting method and device |
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| CN202211652184.0A CN115635958B (en) | 2022-12-22 | 2022-12-22 | Vehicle driving assisting method and device |
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| CN115635958B true CN115635958B (en) | 2023-03-14 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2009096349A (en) * | 2007-10-17 | 2009-05-07 | Mazda Motor Corp | Vehicle driving support device |
| CN108146433B (en) * | 2016-12-06 | 2020-04-21 | 上汽通用汽车有限公司 | Emergency automatic braking system and method for vehicle |
| CN107264523B (en) * | 2017-06-14 | 2019-06-04 | 北京新能源汽车股份有限公司 | Control method for vehicle and system |
| CN112477855B (en) * | 2020-11-10 | 2023-01-06 | 浙江吉利控股集团有限公司 | Vehicle steering auxiliary method, device and equipment |
| KR20220095310A (en) * | 2020-12-29 | 2022-07-07 | 주식회사 에이치엘클레무브 | driver assistance apparatus and driver assistance method |
| CN115230685A (en) * | 2021-08-25 | 2022-10-25 | 广州汽车集团股份有限公司 | Vehicle collision protection control method and advanced driving assistance system |
| CN114670815A (en) * | 2022-04-11 | 2022-06-28 | 驭势（上海）汽车科技有限公司 | Vehicle control method, device, electronic equipment and storage medium |
| CN115140036A (en) * | 2022-07-31 | 2022-10-04 | 东风汽车集团股份有限公司 | Emergency steering control method, device, equipment and readable storage medium |
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