CN111951604B - Vehicle speed determination method, device, equipment and storage medium - Google Patents

Vehicle speed determination method, device, equipment and storage medium Download PDF

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CN111951604B
CN111951604B CN201910353587.7A CN201910353587A CN111951604B CN 111951604 B CN111951604 B CN 111951604B CN 201910353587 A CN201910353587 A CN 201910353587A CN 111951604 B CN111951604 B CN 111951604B
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speed
lane
vehicle
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determining
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CN111951604A (en
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姜禾
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Beijing Baidu Netcom Science and Technology Co Ltd
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Beijing Baidu Netcom Science and Technology Co Ltd
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    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/16—Anti-collision systems
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/01—Detecting movement of traffic to be counted or controlled
    • G08G1/052—Detecting movement of traffic to be counted or controlled with provision for determining speed or overspeed

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Abstract

The invention provides a vehicle speed determination method, a vehicle speed determination device, a vehicle speed determination equipment and a storage medium. The method comprises the following steps: determining at least one speed to be updated of the host vehicle according to at least one running parameter of the host vehicle and a preset updating time step; determining whether the at least one speed to be updated has a speed to be updated which simultaneously meets preset obstacle avoidance constraint conditions, lane constraint conditions and vehicle dynamic model constraint; and if so, taking the speed to be updated meeting the obstacle avoidance constraint condition, the lane constraint condition and the vehicle dynamic model constraint as the speed of the main vehicle at the next updating moment. The speed determined by the embodiment of the invention is more accurate, and the motion of the vehicle in a real road scene can be reflected better.

Description

Vehicle speed determination method, device, equipment and storage medium
Technical Field
The invention relates to the technical field of intelligent traffic, in particular to a vehicle speed determination method, a vehicle speed determination device, vehicle speed determination equipment and a storage medium.
Background
The traffic flow simulation technology is a technology for researching traffic behaviors by using a simulation technology, is a technology for tracking and describing the change of traffic motion along with time and space, and relates to a mathematical model for describing the real-time motion of a traffic transportation system in a certain time. The traffic flow simulation technology can be divided into microscopic traffic flow simulation, intermediate traffic flow simulation and macroscopic traffic flow simulation according to the granularity of a simulation object. The microscopic traffic flow simulation has the highest description degree of detail granularity of elements and behaviors of a traffic Transport System, the description of the traffic flow takes a single vehicle as a basic unit, the microscopic behaviors of the vehicle such as car following, car passing, lane change and the like on a road can be truly reflected, and the microscopic traffic flow simulation has good application in traffic engineering theoretical research, road geometric design scheme analysis, traffic management System design scheme evaluation analysis, road traffic safety analysis and Intelligent traffic System (ITS for short), so that great development is achieved.
The microscopic traffic flow simulation generally adopts the following scheme: the velocity of the host vehicle is calculated by constraints such as the distance and relative velocity of the host vehicle from the preceding vehicle, the desired velocity of the host vehicle, and the like. In the scheme, the track of the vehicle needs to be manually appointed in advance, so that the motion track of the vehicle is single, the motion of the vehicle is different from the motion of a real vehicle in physical constraint, the accuracy of determining the speed of the main vehicle is low, and the motion of the vehicle in a real road scene cannot be reflected.
Disclosure of Invention
The invention provides a vehicle speed determination method, a vehicle speed determination device, vehicle speed determination equipment and a storage medium, which are used for improving the accuracy of vehicle speed determination.
In a first aspect, the present invention provides a vehicle speed determination method comprising:
determining at least one speed to be updated of the host vehicle according to at least one running parameter of the host vehicle and a preset updating time step;
determining whether the at least one speed to be updated has a speed to be updated which simultaneously meets preset obstacle avoidance constraint conditions, lane constraint conditions and vehicle dynamic model constraint;
and if so, taking the speed to be updated meeting the obstacle avoidance constraint condition, the lane constraint condition and the vehicle dynamic model constraint as the speed of the main vehicle at the next updating moment.
In a second aspect, the present invention provides a vehicle speed determination apparatus comprising:
the first determination module is used for determining at least one to-be-updated speed of the main vehicle according to at least one driving parameter of the main vehicle and a preset updating time step length;
the second determination module is used for determining whether the at least one speed to be updated has a speed to be updated which simultaneously meets preset obstacle avoidance constraint conditions, lane constraint conditions and vehicle dynamic model constraints;
and the processing module is used for determining that the speed to be updated meeting the preset obstacle avoidance constraint condition, lane constraint condition and vehicle dynamic model constraint exists at the same time if the second determining module determines that the speed to be updated meeting the preset obstacle avoidance constraint condition, lane constraint condition and vehicle dynamic model constraint exists, and taking the speed to be updated meeting the obstacle avoidance constraint condition, lane constraint condition and vehicle dynamic model constraint as the speed of the main vehicle at the next updating moment.
In a third aspect, the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the computer program implements the method described in any one of the first aspect.
In a fourth aspect, an embodiment of the present invention provides an electronic device, including:
a processor; and
a memory for storing executable instructions of the processor;
wherein the processor is configured to perform the method of any of the first aspects via execution of the executable instructions.
In a fifth aspect, an embodiment of the present application provides a computer program product, including: a computer program stored in a readable storage medium, from which the computer program can be read by at least one processor of an electronic device, execution of the computer program by the at least one processor causing the electronic device to perform the method of any one of the first aspects.
According to the vehicle speed determining method, the vehicle speed determining device, the vehicle speed determining equipment and the storage medium, at least one speed to be updated of the host vehicle is determined according to at least one driving parameter of the host vehicle and a preset updating time step; determining whether the at least one speed to be updated has a speed to be updated which simultaneously meets preset obstacle avoidance constraint conditions, lane constraint conditions and vehicle dynamic model constraint; if the speed of the main vehicle is the speed of the main vehicle at the next updating moment, the accuracy of determining the speed of the vehicle is improved, and the motion of the vehicle in a real road scene can be reflected better.
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The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure.
FIG. 1 is a schematic flow chart diagram illustrating a vehicle speed determination method according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a road scene according to an embodiment of the method provided by the present invention;
FIG. 3 is a schematic structural diagram of an embodiment of a vehicle speed determining apparatus provided by the present invention;
fig. 4 is a schematic structural diagram of an embodiment of an electronic device provided in the present invention.
With the foregoing drawings in mind, certain embodiments of the disclosure have been shown and described in more detail below. These drawings and written description are not intended to limit the scope of the disclosed concepts in any way, but rather to illustrate the concepts of the disclosure to those skilled in the art by reference to specific embodiments.
Detailed Description
Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.
The terms "comprising" and "having," and any variations thereof, in the description and claims of this invention and the drawings described herein are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.
Firstly, the application scenarios related to the invention are introduced:
the vehicle speed determining method provided by the embodiment of the invention is applied to determining the vehicle speed in an active safe driving scene so as to improve the safety performance of the vehicle. The vehicle is, for example, an autonomous vehicle or a general vehicle. The road scene in the embodiment of the invention is, for example, an expressway scene, a city loop, a common road and the like. The following examples are illustrated by highways.
Because the constraint conditions of the existing microscopic traffic flow simulation method are simple, a large amount of artificial adaptability constraints such as vehicle track, speed, turning, lane changing and the like are added according to the road network structure, so that the traffic flow simulation method is difficult to have universality among different road network structures. The method of the embodiment of the invention determines the optimal speed from the reasonable speeds according to the constraint conditions of the traffic flow environment (namely, the road, the adjacent vehicles and the like), is not limited by the road condition, has good adaptivity to the traffic flow environment, can obtain better simulation results for different road networks and traffic flow densities, and greatly increases the diversity of the motion states of the vehicles in the traffic flow.
Because some simple traffic flow simulation models lack consideration of dynamic models of vehicles, the motion mode of the vehicles is greatly different from the motion mode of real vehicles under the conditions of turning, lane changing and the like, the method disclosed by the embodiment of the invention adds consideration of vehicle dynamic model constraint when determining the vehicle speed, so that the vehicle speed meets the physical constraint of vehicle motion.
The method provided by the invention can be realized by the electronic equipment such as a processor executing corresponding software codes, and also can be realized by the electronic equipment performing data interaction with other equipment or a server while executing the corresponding software codes, for example, the other equipment or the server performs part of operations to control the electronic equipment to execute the vehicle speed determination method.
The following embodiments are all described with electronic devices as the executing bodies. In the following embodiments, an autonomous vehicle is described as an example.
The technical solution of the present invention will be described in detail below with specific examples. These several specific embodiments may be combined with each other below, and details of the same or similar concepts or processes may not be repeated in some embodiments.
Fig. 1 is a schematic flow chart of an embodiment of a vehicle speed determination method provided by the invention. As shown in fig. 1, the method provided by this embodiment includes:
step 101, determining at least one speed to be updated of the host vehicle at the next updating moment according to at least one driving parameter of the host vehicle and a preset updating time step.
Specifically, the host vehicle is any vehicle in a current road scene, and the at least one driving parameter of the host vehicle includes, for example: the current speed may be a preset initial speed or a speed updated at a previous update time.
And calculating a plurality of speeds to be updated which can be used as the speed of the main vehicle according to at least one driving parameter of the main vehicle and a preset updating time step length.
Before determining the speed, a road network structure can be constructed according to preset road scene conditions; the road network structure may include: a plurality of parallel lanes; the lane may be implemented by discrete segments.
Determining the number of vehicles and the initial positions of the vehicles in the road network structure according to the preset traffic flow density;
specifically, a road network structure can be constructed according to a highway scene, and the speed of the vehicle is initialized randomly.
The information of the vehicles in the current road scene includes at least one of: size of vehicle, acceleration range, wheel rotation angle range, desired speed, initial position, initial speed, initial direction.
Step 102, determining whether at least one speed to be updated has a speed to be updated which simultaneously meets preset obstacle avoidance constraint conditions, lane constraint conditions and vehicle dynamic model constraint.
Specifically, the vehicle dynamics constraint means that the speed direction change angle of the main vehicle needs to be reasonable, that is, the speed direction change angle of the main vehicle needs to satisfy a certain condition.
The obstacle avoidance constraint condition means that the distance between the main vehicle and the vehicle in front of the current lane where the main vehicle is located needs to meet a certain condition, namely an obstacle avoidance energy function obtained according to the distance between the main vehicle and the vehicle in front of the current lane where the main vehicle is located needs to be smaller than a first preset threshold value.
The lane constraint condition means that a certain constraint condition needs to be satisfied between the host vehicle and a current lane where the host vehicle is located or a target lane to be entered by the host vehicle, such as an included angle or a distance between the host vehicle and the current lane direction and an included angle or a distance between the host vehicle and the target lane direction.
The speed to be updated which simultaneously meets the obstacle avoidance constraint condition, the lane constraint condition and the vehicle dynamics model constraint needs to be determined.
In an embodiment of the present invention, it may specifically be determined whether there is a speed to be updated that simultaneously satisfies the obstacle avoidance constraint condition, the lane constraint condition, and the vehicle dynamics model constraint, as follows:
determining the speed direction change angle of each speed to be updated at the next updating moment according to each speed to be updated;
determining whether the speed direction change angle of each speed to be updated at the next updating moment is reasonable or not according to the relation between the preset speed and the speed direction change angle and the wheel rotation angle range of the main vehicle;
if the speed direction change angle of each speed to be updated at the next updating moment is reasonable, each speed to be updated meets the constraint of the vehicle dynamic model;
and determining whether each speed to be updated meeting the constraint of the vehicle dynamic model meets obstacle avoidance constraint conditions and lane constraint conditions.
Specifically, it may be determined whether each speed to be updated satisfies a vehicle dynamics model constraint, and if so, it may be further determined whether an obstacle avoidance constraint condition and a lane constraint condition are satisfied.
And satisfying the vehicle dynamics model constraint, namely determining whether the speed direction change angle of the speed to be updated at the next updating moment is reasonable, and if so, satisfying the vehicle dynamics model constraint.
Whether the speed direction change angle is reasonable or not can be determined according to the wheel rotation angle range and the relation between the speed and the speed direction change angle, for example, whether the speed direction change angle is within the wheel rotation angle range or not, if yes, the speed and speed direction change angle relation is met, the speed direction change angle is reasonable, for example, the speed to be updated is high, the speed direction change angle is small, and otherwise, the vehicle runs dangerously.
The speed direction change angle corresponding to the speed to be updated is determined according to the speed to be updated, the current wheel rotation angle, the wheelbase of the main vehicle and the update time step length.
Further, determining whether each speed to be updated meeting the vehicle dynamics model constraint meets the obstacle avoidance constraint condition and the lane constraint condition, which can be specifically realized by adopting the following method:
determining an obstacle avoidance energy function in the obstacle avoidance constraint condition corresponding to each speed to be updated according to each speed to be updated;
if the value of the obstacle avoidance energy function is smaller than a first preset threshold value, determining that each speed to be updated meets the obstacle avoidance constraint condition;
and determining whether each speed to be updated meets the lane constraint condition.
Specifically, whether the speed to be updated of the vehicle meets the obstacle avoidance constraint condition or not is determined, and then whether the speed to be updated of the vehicle meets the lane constraint condition or not is determined.
Determining whether an obstacle avoidance constraint condition is met, namely determining whether a value of an obstacle avoidance energy function corresponding to the speed to be updated is smaller than a first preset threshold, if so, the speed to be updated meets the obstacle avoidance constraint condition, and if not, the speed to be updated does not meet the obstacle avoidance constraint condition. The obstacle avoidance energy function can be determined according to the distance between the main vehicle and the front vehicle. The larger the value of the obstacle avoidance energy function is, the higher the possibility that the host vehicle collides with the preceding vehicle is.
Further, determining whether each speed to be updated meeting the vehicle dynamics model constraint and the obstacle avoidance constraint conditions meets the lane constraint conditions or not, and specifically adopting the following method to realize:
according to each speed to be updated, determining a speed direction energy function, a lane distance energy function and a lane direction energy function in lane constraint conditions corresponding to the speed to be updated;
and if the value of the speed direction energy function is smaller than a second preset threshold, the value of the lane distance energy function is smaller than a third preset threshold, and the value of the lane direction energy function is smaller than a fourth preset threshold, determining that each speed to be updated meets the lane constraint condition.
Specifically, whether a lane constraint condition is met is determined, that is, whether the values of a speed direction energy function, a lane distance energy function and a lane direction energy function corresponding to the speed to be updated are smaller than respective corresponding preset thresholds or not is determined, if the values are smaller than the respective preset thresholds, the speed to be updated meets the lane constraint condition, and if the value of at least one function is larger than or equal to the preset threshold, the lane constraint condition is not met.
The speed direction energy function can be determined according to the included angle between the main vehicle and the current lane direction (or the target lane direction), and the larger the numerical value of the speed direction energy function is, the larger the included angle between the main vehicle and the current lane direction is, the more dangerous the vehicle runs.
The lane distance energy function may be determined according to the distance between the host vehicle and the current lane (or the target lane), specifically, the distance between the host vehicle and the center line of the current lane, and the larger the value of the lane distance energy function, the larger the distance between the host vehicle and the current lane, the more dangerous the vehicle runs.
The lane direction energy function can be determined according to the included angle between the direction of the main vehicle and the current lane direction (or the target lane direction), and the larger the value of the lane direction energy function is, the larger the included angle between the direction of the main vehicle and the current lane direction is, the more dangerous the vehicle runs.
And 103, if the speed to be updated meets the obstacle avoidance constraint condition, the lane constraint condition and the vehicle dynamic model constraint, taking the speed to be updated as the speed of the main vehicle at the next updating moment.
Further, if there are a plurality of speeds to be updated that satisfy the obstacle avoidance constraint condition, the lane constraint condition, and the vehicle dynamics model constraint, a better speed to be updated may be determined as the speed of the host vehicle at the next update time:
and searching the speed to be updated with the minimum sum of the obstacle avoidance energy function, the speed direction energy function, the lane distance energy function and the lane direction energy function from the speeds to be updated which meet the obstacle avoidance constraint condition, the lane constraint condition and the vehicle dynamic model constraint.
Further, in an embodiment of the present invention, the method may further include the following steps:
if the value of the obstacle avoidance energy function of the main vehicle is zero, determining a speed expected constraint function corresponding to the speed to be updated according to a preset expected speed and the speed to be updated of the main vehicle;
the searching for the speed to be updated with the minimum sum of the obstacle avoidance energy function, the speed direction energy function, the lane distance energy function and the lane direction energy function from the speeds to be updated which meet the obstacle avoidance constraint condition, the lane constraint condition and the vehicle dynamics model constraint includes:
and searching the speed to be updated with the minimum sum of the obstacle avoidance energy function, the speed direction energy function, the lane distance energy function, the lane direction energy function and the speed expectation constraint function from the speeds to be updated which meet the obstacle avoidance constraint condition, the lane constraint condition and the vehicle dynamic model constraint.
Specifically, if the value of the obstacle avoidance energy function is 0, it indicates that the collision with the preceding vehicle does not occur, the speed of the host vehicle may be updated to a speed as close as possible to the desired speed, and the speed desired constraint function may be obtained according to a difference between the desired speed and the speed to be updated.
Specifically, the speed to be updated, which minimizes the sum of the obstacle avoidance energy function, the speed direction energy function, the lane distance energy function, the lane direction energy function, and the speed expectation constraint function, may be used as the speed of the host vehicle at the next update time.
Further, the position of the host vehicle at the next update time may be determined based on the speed to be updated.
The position of the next update time may be calculated based on the current position of the host vehicle, the update time step, and the velocity of the next update time.
The method of the embodiment comprises the steps of determining at least one speed to be updated of a main vehicle according to the current speed, the acceleration range, the wheel corner range and the preset updating time step of the main vehicle; determining whether the at least one speed to be updated has a speed to be updated which simultaneously meets preset obstacle avoidance constraint conditions, lane constraint conditions and vehicle dynamic model constraint; if the speed of the main vehicle is the speed of the main vehicle at the next updating moment, the accuracy of determining the speed of the vehicle is improved, and the motion of the vehicle in a real road scene can be reflected better.
On the basis of the above embodiment, further, determining the speed direction change angle of the host vehicle at the next update time may specifically be implemented as follows:
and determining the speed direction change angle of the main vehicle at the next updating moment according to the wheel rotation angle, the wheel base and the speed to be updated of the main vehicle.
Specifically, the speed direction change angle Δ θ of the speed to be updated at the next update time can be determined according to the following formula (1);
Δθ＝tan(Φ)/L×v0×Δt (1)；
wherein Φ is a wheel rotation angle, L is a wheel base, v0 is the speed to be updated, and Δ t is the update time step.
Further, determining whether the speed direction change angle of each speed to be updated at the next update time is reasonable may specifically include the following steps:
determining whether the speed-direction change angle is within a wheel turning angle range of the host vehicle;
and if so, determining whether the speed direction change angle is reasonable or not according to the relation between the speed and the speed direction change angle.
Specifically, if the speed direction change angle is within the wheel rotation angle range of the main vehicle, it is preliminarily determined that the speed direction change angle is reasonable, and it is further determined whether the speed direction change angle is reasonable or not through the relationship between the speed and the speed direction change angle, that is, if the speed is large, the speed direction change angle should be small and within a certain range.
On the basis of the above embodiment, further, before determining the obstacle avoidance energy function, the following operations may be performed:
if a front vehicle exists in a current lane where the main vehicle is located, determining a first distance between the main vehicle and the front vehicle at the next updating moment along the current lane direction according to the speed to be updated of the main vehicle and the current speed of the front vehicle, and predicting a second distance between the main vehicle and the front vehicle along the current lane direction after a preset time;
and if the first distance and the second distance are greater than a preset safety distance, determining the obstacle avoidance energy function.
Specifically, if a front vehicle exists in a current lane where the host vehicle is located, a first distance between the host vehicle and the front vehicle at the next updating time is determined, a second distance between the host vehicle and the front vehicle after a preset time length is predicted, and if the first distance or the second distance is smaller than a preset safe distance, the host vehicle and the front vehicle may collide, and the speed to be updated is abandoned.
And if the first distance and the second distance are greater than the preset safety distance, determining an obstacle avoidance energy function. And further determining whether the speed to be updated meets the obstacle avoidance constraint condition or not according to the obstacle avoidance energy function.
The safe distance is a distance which does not collide in a safe time when the current speed (i.e. the speed to be updated) of the main vehicle is maintained and the speed of the front vehicle is reduced to 0.
Wherein the first distance s can be obtained according to the following formula:
s＝p0+v0×Δt–(p1+v1×Δt)；
wherein p0 and p1 are the current positions of the host vehicle and the vehicle ahead of the current lane, v0 is the speed to be updated, and v1 is the current vehicle speed of the vehicle ahead of the current lane;
second distance spThis can be obtained according to the following formula:
sp＝p0+v0×Δt×εp–(p1+v1×Δt×εp)；
wherein epsilonpIs a preset prediction step length; Δ t × εpIs a preset duration.
Further, determining an obstacle avoidance energy function in the obstacle avoidance constraint condition corresponding to each speed to be updated may specifically be implemented in the following manner:
if the main vehicle is in a non-lane-changing state, determining the obstacle avoidance energy function according to the speed to be updated, the first distance, the second distance and preset safety time;
if the main vehicle is in a lane change state, determining the obstacle avoidance energy function according to the speed to be updated, the first distance, the second distance, the third distance, the fourth distance and preset safety time; the third distance is a distance between the host vehicle and a vehicle ahead of the target lane, and the fourth distance is a predicted distance between the host vehicle and the vehicle ahead of the target lane after a preset time period.
Specifically, if the main vehicle is in a non-lane change state, that is, the main vehicle always runs along the current lane where the main vehicle is located, the obstacle avoidance energy function enRep corresponding to the speed to be updated can be determined according to the following formula (2);
enRep＝ρrep×(v0×tsafe-min(s，sp)) (2)；
where ρ isrepIs a preset first weight, tsafeIs a preset safe time, s is the first distance, spIs the second distance; formulas for calculating the first distance and the second distance are as described in the foregoing embodiments;
if the host vehicle is in a lane changing state, namely the host vehicle changes lanes from a current lane to a target lane, determining an obstacle avoidance energy function enRep corresponding to the speed to be updated according to the following formula (3);
enRep＝ρrep×(v0×tsafe-min(s，sp，st，stp)) (3)；
wherein s istIs the third distance, stpIs the fourth distance; the third distance is the distance between the main vehicle and the vehicle in front of the target lane, and the fourth distance is the predicted distance between the main vehicle and the vehicle in front of the target lane after the preset time length; specifically, the calculation can be performed according to the following formula:
st＝p0+v0×Δt–(p2+v2×Δt)；
stp＝p0+v0×Δt×εp–(p2+v2×Δt×εp)；
wherein p0 and p2 are the current positions of the host vehicle and the front vehicle of the target lane respectively, v0 is the speed to be updated, and v2 is the current vehicle speed of the front vehicle of the target lane; Δ t × εpIs a preset duration.
Further, before determining the obstacle avoidance energy function, it may be further determined whether the host vehicle is in a lane change state, if so, the obstacle avoidance energy function is determined according to the speed to be updated, the first distance, the second distance, the third distance, the fourth distance and preset safety time, and if not, the obstacle avoidance energy function is determined according to the speed to be updated, the first distance, the second distance and preset safety time.
On the basis of the foregoing embodiment, further, the following manner may be specifically adopted to determine the speed direction energy function, the lane distance energy function, and the lane direction energy function in the lane constraint condition:
if the main vehicle is in the lane changing state, the following mode can be adopted:
if a first included angle between the main vehicle and the current lane where the main vehicle is located is larger than a preset first angle threshold value, determining the speed direction energy function according to the first included angle;
if the first included angle is smaller than the first angle threshold value and a fifth distance between the main vehicle and a target lane to be entered by the main vehicle is larger than a preset second distance threshold value, determining a lane distance energy function according to the fifth distance between the main vehicle and the target lane;
and if the first included angle is smaller than the first preset threshold value, the distance between the main vehicle and the target lane is smaller than the second distance threshold value, and the second included angle between the main vehicle and the direction of the target lane is larger than a preset second angle threshold value, determining the lane direction energy function according to the second included angle of the main vehicle.
Specifically, the main vehicle is in a lane changing state, that is, the main vehicle changes the lane from the current lane to the target lane, and a first included angle between the main vehicle and the current lane where the main vehicle is located is greater than a preset first angle threshold, at this time, the size of the first included angle is kept as unchanged as possible, the first included angle can be properly reduced, preferably not increased, and otherwise, the risk of retrograde motion may be caused.
Determining a speed direction energy function enVel corresponding to the speed to be updated according to the following formula (4);
enVel＝ρvel×tan(|Δθ'|) (4)；
where ρ isvelThe weight is a preset second weight, and the delta theta' is a first included angle between the main vehicle and the current lane where the main vehicle is located. The first included angle is a first included angle between the direction of the main vehicle and the current lane where the main vehicle is located, and when the speed of the main vehicle is not 0, the direction of the main vehicle is the same as the speed direction.
Namely, it is required to ensure that the speed direction energy function is required to be smaller than a certain threshold value, namely, a first included angle between the main vehicle and the current lane where the main vehicle is located is required to be smaller than a preset first angle threshold value, otherwise, the speed to be updated does not meet the lane constraint condition.
If the first included angle is smaller than a first angle threshold value and a fifth distance between the main vehicle and a target lane to be entered by the main vehicle is larger than a preset second distance threshold value, determining a lane distance energy function enLanePos corresponding to the speed to be updated according to the following formula (5);
enLanePos＝ρlanePos×slane×slane (5)；
where ρ islanePosIs a preset third weight, at this time slaneIs a fifth distance between the host vehicle and the target lane.
The lane distance energy function corresponding to the speed to be updated also meets a certain condition, namely, the lane distance energy function is smaller than a certain threshold value, namely, the distance between the main vehicle and the target lane is smaller than a certain threshold value, so that the main vehicle can enter the target lane to run, and the speed to be updated can be ensured to meet the lane constraint condition.
If the first included angle is smaller than a first preset threshold value, the fifth distance between the main vehicle and the target lane is smaller than a second distance threshold value, and the second included angle between the main vehicle and the target lane is larger than a preset second angle threshold value, determining a lane direction energy function enLaneDir corresponding to the speed to be updated according to the following formula (6);
enLaneDir＝ρlaneDir×tan(Δθ") (6)；
where ρ islaneDirIs a preset fourth weight, where Δ θ "is a second angle between the host vehicle and the target lane direction.
The lane direction energy function corresponding to the speed to be updated also meets a certain condition, namely, the lane direction energy function is smaller than a certain threshold value, namely, a second included angle between the main vehicle and the target lane direction is also smaller than a second angle threshold value, so that the speed direction of the main vehicle does not deviate from the target lane, and the speed to be updated can be ensured to meet the lane constraint condition.
In an embodiment of the present invention, when a fifth distance between the host vehicle and the target lane is smaller than the second distance threshold and a second included angle between the host vehicle and the target lane is smaller than a second angle threshold, the host vehicle enters the target lane at this time, and the host vehicle is ensured to be opened along the target lane as much as possible, that is, a speed-direction energy function is as small as possible.
If the main vehicle is in a non-lane-changing state, the following mode can be adopted:
if the distance between the host vehicle and the current lane where the host vehicle is located is larger than a preset second distance threshold, determining the lane distance energy function according to the distance between the host vehicle and the current lane where the host vehicle is located;
if the distance between the main vehicle and the current lane where the main vehicle is located is smaller than the second distance threshold value, and a third included angle between the main vehicle and the current lane where the main vehicle is located is larger than a preset first angle threshold value, determining an energy function of the lane direction according to the third included angle;
and if the distance between the main vehicle and the current lane where the main vehicle is located is smaller than the second distance threshold value, and the third included angle is smaller than the first angle threshold value, determining the speed direction energy function according to the third included angle.
Specifically, when the main vehicle is in a non-lane-changing state, the main vehicle runs along the current lane, and the distance between the main vehicle and the current lane where the main vehicle is located is greater than a preset distanceDetermining a lane distance energy function enLanePos corresponding to the speed to be updated according to the formula (5) by using the two distance thresholds, wherein s in the formula (5) islaneIs the distance between the host vehicle and the current lane.
The lane distance energy function corresponding to the speed to be updated also meets a certain condition, namely, the lane distance energy function is smaller than a certain threshold value, namely, the distance between the main vehicle and the current lane is smaller than a certain threshold value, so that the main vehicle is ensured not to deviate from the current lane and enter other lanes, and the speed to be updated can be ensured to meet the lane constraint condition.
If the distance between the host vehicle and the current lane is smaller than the second distance threshold and the third included angle between the host vehicle and the current lane direction is larger than the preset first angle threshold, the lane direction energy function enLaneDir corresponding to the speed to be updated can be determined according to the formula (6), and at this time, the delta theta' is the third included angle between the host vehicle and the current lane direction.
The lane direction energy function corresponding to the speed to be updated also needs to meet a certain condition, namely, the lane direction energy function is smaller than a certain threshold value, namely, a third included angle between the main vehicle and the current lane direction also needs to be smaller than a first angle threshold value, so that the speed direction of the main vehicle does not deviate from the current lane, and the speed to be updated can be guaranteed to meet the lane constraint condition.
And a third included angle between the main vehicle and the current lane direction is larger than a preset first angle threshold, and the size of the third included angle is reduced as much as possible.
If the distance between the host vehicle and the current lane is smaller than the second distance threshold and the third included angle is smaller than the first angle threshold, the speed direction energy function enVel corresponding to the speed to be updated can be determined according to the formula (4), and at this time, Δ θ' in the formula (4) is the third included angle between the host vehicle and the current lane direction.
The energy function of the speed direction needs to be ensured to be smaller than a certain threshold value, namely, the third included angle between the main vehicle and the current lane where the main vehicle is located needs to be smaller than a preset first angle threshold value, the main vehicle is ensured to be opened along the direction of the current lane as much as possible, and otherwise, the speed to be updated does not meet the lane constraint condition.
The first angle threshold and the second angle threshold may be equal to or different from each other, which is not limited in the embodiment of the present invention.
In the specific embodiment, the speed of the vehicle is determined according to the vehicle dynamic model constraint, the obstacle avoidance constraint condition and the lane constraint condition, so that the accuracy of determining the speed of the vehicle is improved, and the motion of the vehicle in a real road scene can be reflected better.
On the basis of the foregoing embodiment, further, the method of this embodiment may further include:
determining whether a host vehicle is driving from a current lane in which the host vehicle is located to a target lane; the target lane is a lane adjacent to the current lane;
if so, determining that the main vehicle is in a lane changing state;
if not, determining that the main vehicle is in the non-lane-changing state.
In an embodiment of the present invention, the method further includes:
determining whether the main vehicle meets a preset lane-changing starting condition;
if the main vehicle meets the lane-changing starting condition, determining whether the main vehicle meets a preset lane-changing decision condition;
and if the main vehicle meets the lane change determining condition, controlling the main vehicle to change the lane from the current lane where the main vehicle is located to a target lane.
Specifically, it is determined whether the host vehicle is in a lane change state, that is, whether the host vehicle is driving to change lanes from the current lane to the target lane, which is previously determined whether the host vehicle is changing lanes:
firstly, whether the main vehicle meets a lane change starting condition or not is determined, if yes, whether the main vehicle meets a lane change determining condition or not is further determined, if yes, the main vehicle is controlled to change the lane from a current lane to a target lane, and at the moment, the main vehicle is in a lane change state.
Further, the determination as to whether the host vehicle satisfies the lane change starting condition may specifically be performed in the following manner:
determining whether an adjacent lane exists in a current lane where the host vehicle is located;
if the current lane where the main vehicle is located has an adjacent lane, determining whether a front vehicle exists in the current lane;
if the current lane has the front vehicle, determining whether the front vehicle is in a non-lane-changing state;
and if the front vehicle is in a non-lane-changing state, determining that the main vehicle meets the lane-changing starting condition.
Specifically, as shown in fig. 2, if there is an adjacent lane in the current lane where the host vehicle 1 is located, there is a front vehicle 2 in the current lane, and the front vehicle is in a non-lane-changing state, the host vehicle satisfies a lane-changing starting condition, and may start lane changing.
Further, it is determined whether the host vehicle meets a lane change determination condition, and if the lane change determination condition is met, the lane change is performed to the target lane, which may specifically be as follows:
determining whether the difference between the distance between the main vehicle and a preceding vehicle in the current lane and the distance between the main vehicle and a preceding vehicle in the target lane is smaller than a preset first distance threshold value;
if so, determining whether the distance between the main vehicle and a front vehicle in the target lane along the direction of the target lane is greater than a preset safety distance;
if so, determining whether the distance between the main vehicle and a rear vehicle in the target lane along the direction of the target lane is greater than the safe distance; the target lane is an adjacent lane of the current lane;
if yes, the main vehicle is determined to meet the lane change determining condition.
Specifically, as shown in fig. 2, if the distance between the host vehicle 1 and the front vehicle 2 in the current lane is assumed to be L1, the distance between the host vehicle 1 and the front vehicle 4 in the target lane is assumed to be L2, and the difference between L1 and L2 is smaller than the first distance threshold, and the distance between the host vehicle 1 and the front vehicle 4 in the target lane is greater than the safety distance, and the distance between the host vehicle 1 and the rear vehicle 3 in the target lane is also greater than the safety distance, the host vehicle satisfies the lane change determination condition, and can change the lane from the current lane to the target lane.
In an embodiment of the present invention, the speed expectation constraint function enVelLimit corresponding to the speed to be updated may be determined according to the following formula (7);
enVelLimit＝ρvelLimit×|v0-vlimit| (7)；
where ρ isvelLimitIs a preset fifth weight, vlimitTo the desired velocity, v0 is the velocity to be updated.
In one embodiment of the invention, after determining the velocity of the host vehicle at the next update time, the velocity may be interpolated, i.e. the change in velocity of the host vehicle at the next update time is smooth, gradually changing from the current velocity to the determined velocity to be updated.
Fig. 3 is a structural diagram of an embodiment of a vehicle speed determination apparatus provided in the present invention, and as shown in fig. 3, the vehicle speed determination apparatus of the embodiment includes:
a first determining module 301, configured to determine at least one to-be-updated speed of a host vehicle according to at least one driving parameter of the host vehicle and a preset update time step;
a second determining module 302, configured to determine whether there is a to-be-updated speed that simultaneously satisfies a preset obstacle avoidance constraint condition, a preset lane constraint condition, and a preset vehicle dynamics model constraint in the at least one to-be-updated speed;
and the processing module 303 is configured to, if it is determined by the second determining module that the speed to be updated that satisfies the preset obstacle avoidance constraint condition, the preset lane constraint condition, and the preset vehicle dynamics model constraint at the same time exists, use the speed to be updated that satisfies the obstacle avoidance constraint condition, the preset lane constraint condition, and the preset vehicle dynamics model constraint as the speed of the host vehicle at the next update time.
In a possible implementation manner, the second determining module 302 is specifically configured to:
determining the speed direction change angle of each speed to be updated at the next updating moment according to each speed to be updated;
determining whether the speed direction change angle of each speed to be updated at the next updating moment is reasonable or not according to the relation between the preset speed and the speed direction change angle and the wheel rotation angle range of the main vehicle;
if the speed direction change angle of each speed to be updated at the next updating moment is reasonable, each speed to be updated meets the constraint of the vehicle dynamic model;
and determining whether each speed to be updated meeting the vehicle dynamic model constraint meets the obstacle avoidance constraint condition and the lane constraint condition.
In a possible implementation manner, the second determining module 302 is specifically configured to:
determining an obstacle avoidance energy function in the obstacle avoidance constraint condition corresponding to each speed to be updated according to each speed to be updated;
if the value of the obstacle avoidance energy function is smaller than a first preset threshold value, determining that each speed to be updated meets the obstacle avoidance constraint condition;
and determining whether each speed to be updated meets the lane constraint condition.
In a possible implementation manner, the second determining module 302 is specifically configured to:
according to each speed to be updated, determining a speed direction energy function, a lane distance energy function and a lane direction energy function in the lane constraint condition corresponding to the speed to be updated;
and if the value of the speed direction energy function is smaller than a second preset threshold, the value of the lane distance energy function is smaller than a third preset threshold, and the value of the lane direction energy function is smaller than a fourth preset threshold, determining that each speed to be updated meets the lane constraint condition.
In a possible implementation manner, the processing module 302 is specifically configured to:
and searching the speed to be updated which enables the sum of the obstacle avoidance energy function, the speed direction energy function, the lane distance energy function and the lane direction energy function to be minimum from the speeds to be updated which meet the obstacle avoidance constraint condition, the lane constraint condition and the vehicle dynamic model constraint, and taking the speed to be updated as the speed of the main vehicle at the next updating moment.
In a possible implementation manner, the second determining module 302 is specifically configured to:
determining the speed direction change angle of the main vehicle at the next updating moment according to the wheel rotation angle, the wheel base and the speed to be updated of the main vehicle;
determining whether the speed-direction change angle is within a wheel turning angle range of the host vehicle;
and if so, determining whether the speed direction change angle is reasonable or not according to the relation between the speed and the speed direction change angle.
In a possible implementation manner, the second determining module 302 is further configured to:
if a front vehicle exists in a current lane where the main vehicle is located, determining a first distance between the main vehicle and the front vehicle at the next updating moment along the current lane direction according to the speed to be updated of the main vehicle and the current speed of the front vehicle, and predicting a second distance between the main vehicle and the front vehicle along the current lane direction after a preset time;
and if the first distance and the second distance are greater than a preset safety distance, determining the obstacle avoidance energy function.
In a possible implementation manner, the second determining module 302 is specifically configured to:
if the main vehicle is in a non-lane-changing state, determining the obstacle avoidance energy function according to the speed to be updated, the first distance, the second distance and preset safety time;
if the main vehicle is in a lane change state, determining the obstacle avoidance energy function according to the speed to be updated, the first distance, the second distance, the third distance, the fourth distance and preset safety time; the third distance is a distance between the host vehicle and a vehicle ahead of the target lane, and the fourth distance is a predicted distance between the host vehicle and the vehicle ahead of the target lane after a preset time period.
In a possible implementation manner, if the host vehicle is in the lane change state, the second determining module 302 is specifically configured to:
if a first included angle between the main vehicle and the current lane where the main vehicle is located is larger than a preset first angle threshold value, determining the speed direction energy function according to the first included angle;
if the first included angle is smaller than the first angle threshold value and a fifth distance between the main vehicle and a target lane to be entered by the main vehicle is larger than a preset second distance threshold value, determining a lane distance energy function according to the fifth distance between the main vehicle and the target lane;
and if the first included angle is smaller than the first preset threshold value, the distance between the main vehicle and the target lane is smaller than the second distance threshold value, and the second included angle between the main vehicle and the direction of the target lane is larger than a preset second angle threshold value, determining the lane direction energy function according to the second included angle of the main vehicle.
In a possible implementation manner, if the host vehicle is in the non-lane-change state, the second determining module 302 is specifically configured to:
if the distance between the host vehicle and the current lane where the host vehicle is located is larger than a preset second distance threshold, determining the lane distance energy function according to the distance between the host vehicle and the current lane where the host vehicle is located;
if the distance between the main vehicle and the current lane where the main vehicle is located is smaller than the second distance threshold value, and a third included angle between the main vehicle and the current lane where the main vehicle is located is larger than a preset first angle threshold value, determining the lane direction energy function according to the third included angle of the main vehicle;
and if the distance between the main vehicle and the current lane where the main vehicle is located is smaller than the second distance threshold value, and the third included angle is smaller than the first angle threshold value, determining the speed direction energy function according to the third included angle.
In a possible implementation manner, the processing module 303 is further configured to:
if the value of the obstacle avoidance energy function of the main vehicle is zero, determining a speed expected constraint function corresponding to the speed to be updated according to a preset expected speed and the speed to be updated of the main vehicle;
and searching the speed to be updated with the minimum sum of the obstacle avoidance energy function, the speed direction energy function, the lane distance energy function, the lane direction energy function and the speed expectation constraint function from the speeds to be updated which meet the obstacle avoidance constraint condition, the lane constraint condition and the vehicle dynamic model constraint.
In a possible implementation manner, the processing module 303 is further configured to:
determining whether the host vehicle is driving from a current lane in which the host vehicle is located to a target lane; the target lane is a lane adjacent to the current lane;
if so, determining that the main vehicle is in a lane changing state;
if not, determining that the main vehicle is in a non-lane-changing state.
In a possible implementation manner, the processing module 303 is further configured to:
determining whether the main vehicle meets a preset lane-changing starting condition;
if the main vehicle meets the lane-changing starting condition, determining whether the main vehicle meets a preset lane-changing decision condition;
and if the main vehicle meets the lane change determining condition, controlling the main vehicle to change the lane from the current lane where the main vehicle is located to a target lane.
In a possible implementation manner, the processing module 303 is specifically configured to:
determining whether an adjacent lane exists in a current lane where the host vehicle is located;
if the current lane where the main vehicle is located has an adjacent lane, determining whether a front vehicle exists in the current lane;
if the current lane has the front vehicle, determining whether the front vehicle is in a non-lane-changing state;
and if the front vehicle is in a non-lane-changing state, determining that the main vehicle meets the lane-changing starting condition.
In a possible implementation manner, the processing module 303 is specifically configured to:
determining whether a difference between a distance between the host vehicle and a preceding vehicle in the current lane and a distance between the host vehicle and a preceding vehicle in a target lane is less than a preset first distance threshold;
if so, determining whether the distance between the main vehicle and a front vehicle in the target lane along the direction of the target lane is greater than a preset safety distance;
if so, determining whether the distance between the main vehicle and a rear vehicle in the target lane along the direction of the target lane is greater than the safe distance; the target lane is a lane adjacent to the current lane;
and if so, determining that the main vehicle meets the lane change decision condition.
In a possible implementation manner, the first determining module 301 is specifically configured to:
constructing a road network structure according to preset road scene conditions; the road network structure comprises: a plurality of parallel lanes;
determining the number of vehicles and the initial positions of the vehicles in the road network structure according to preset traffic flow density;
wherein the information of the vehicle comprises at least one of: size of vehicle, acceleration range, wheel rotation angle range, desired speed, initial position, initial speed, initial direction.
In a possible implementation manner, the processing module 303 is further configured to:
determining the position of the host vehicle at the next update time according to the speed of the host vehicle at the next update time.
In a possible implementation manner, the second determining module 302 is specifically configured to:
determining a speed direction change angle delta theta of the speed to be updated at the next updating moment according to the following formula (1);
Δθ＝tan(Φ)/L×v0×Δt (1)；
wherein Φ is a wheel rotation angle, L is a wheel base, v0 is the speed to be updated, and Δ t is the update time step.
In a possible implementation manner, the second determining module 302 is specifically configured to:
if the main vehicle is in a non-lane-changing state, determining an obstacle avoidance energy function enRep corresponding to the speed to be updated according to the following formula (2);
enRep＝ρrep×(v0×tsafe-min(s，sp)) (2)；
where ρ isrepIs a preset first weight, tsafeIs a preset safe time, s is the first distance, spIs the second distance; s ═ p0+ v0 × Δ t- (p1+ v1 × Δ t); sp＝p0+v0×Δt×εp–(p1+v1×Δt×εp) (ii) a p0, p1 are the current positions of the host vehicle and the vehicle ahead of the current lane, v0 is the speed to be updated, v1 is the current vehicle speed, epsilon, of the vehicle ahead of the current lanepIs a preset prediction step length;
if the main vehicle is in the lane changing state, determining an obstacle avoidance energy function enRep corresponding to the speed to be updated according to the following formula (3);
enRep＝ρrep×(v0×tsafe-min(s，sp，st，stp)) (3)；
wherein s istIs the third distance, stpIs the fourth distance;
st＝p0+v0×Δt–(p2+v2×Δt)；
stp＝p0+v0×Δt×εp–(p2+v2×Δt×εp)；
wherein p0 and p2 are the current positions of the host vehicle and the front vehicle of the target lane respectively, v0 is the speed to be updated, and v2 is the current vehicle speed of the front vehicle of the target lane.
In a possible implementation manner, the second determining module 302 is specifically configured to:
determining a speed direction energy function enVel corresponding to the speed to be updated according to the following formula (4);
enVel＝ρvel×tan(|Δθ'|) (4)；
where ρ isvelAnd delta theta' is the first included angle or the third included angle and is a preset second weight.
In a possible implementation manner, the second determining module 302 is specifically configured to:
determining a lane distance energy function enLanePos corresponding to the speed to be updated according to the following formula (5);
enLanePos＝ρlanePos×slane×slane (5)；
where ρ islanePosIs a preset third weight, slaneIs the distance between the host vehicle and a target lane or the distance between the host vehicle and the current lane where the host vehicle is located.
In a possible implementation manner, the second determining module 302 is specifically configured to:
determining a lane direction energy function enLaneDir corresponding to the speed to be updated according to the following formula (6);
enLaneDir＝ρlaneDir×tan(Δθ") (6)；
where ρ islaneDirAnd delta theta' is the second included angle or the third included angle and is a preset fourth weight.
In a possible implementation manner, the processing module 303 is specifically configured to:
determining a speed expected constraint function envvellimit corresponding to the speed to be updated according to the following formula (7);
enVelLimit＝ρvelLimit×|v0-vlimit| (7)；
where ρ isvelLimitIs a preset fifth weight, vlimitV0 is the speed to be updated for the desired speed.
The apparatus of this embodiment may be configured to implement the technical solutions of the above method embodiments, and the implementation principles and technical effects are similar, which are not described herein again.
Fig. 4 is a structural diagram of an embodiment of an electronic device provided in the present invention, and as shown in fig. 4, the electronic device includes:
a processor 401, and a memory 402 for storing executable instructions for the processor 401.
Optionally, the method may further include: a transceiver 403 for enabling communication with other devices.
The above components may communicate over one or more buses.
The processor 401 is configured to execute the corresponding method in the foregoing method embodiment by executing the executable instruction, and the specific implementation process of the method may refer to the foregoing method embodiment, which is not described herein again.
The embodiment of the present invention further provides a computer-readable storage medium, where a computer program is stored, and when the computer program is executed by a processor, the method in the foregoing method embodiment is implemented.
There is also provided, in accordance with an embodiment of the present application, a computer program product, including: a computer program, stored in a readable storage medium, from which at least one processor of the electronic device can read the computer program, the at least one processor executing the computer program causing the electronic device to perform the aspects of the electronic device in any of the method embodiments described above.
Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.
It will be understood that the present disclosure is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims (21)

1. A vehicle speed determination method, characterized by comprising:
determining at least one speed to be updated of the host vehicle according to at least one running parameter of the host vehicle and a preset updating time step;
determining whether the at least one speed to be updated has a speed to be updated which simultaneously meets preset obstacle avoidance constraint conditions, lane constraint conditions and vehicle dynamic model constraint; the speed direction change angle of the speed to be updated meeting the vehicle dynamic model constraint at the next updating moment is reasonable, and the speed direction change angle corresponding to the speed to be updated is determined according to the speed to be updated, the current wheel rotation angle, the wheelbase of the main vehicle and the updating time step;
and if so, taking the speed to be updated meeting the obstacle avoidance constraint condition, the lane constraint condition and the vehicle dynamic model constraint as the speed of the main vehicle at the next updating moment.
2. The method of claim 1, wherein the determining whether there is a speed to be updated that satisfies preset obstacle avoidance constraints, lane constraints, and vehicle dynamics model constraints at the same time comprises:
determining the speed direction change angle of each speed to be updated at the next updating moment according to each speed to be updated;
determining whether the speed direction change angle of each speed to be updated at the next updating moment is reasonable or not according to the relationship between the preset speed and the speed direction change angle and the wheel rotation angle range of the main vehicle;
if the speed direction change angle of each speed to be updated at the next updating moment is reasonable, each speed to be updated meets the constraint of the vehicle dynamic model;
and determining whether each speed to be updated meeting the vehicle dynamic model constraint meets the obstacle avoidance constraint condition and the lane constraint condition.
3. The method of claim 2, wherein the determining whether each of the to-be-updated speeds satisfying the vehicle dynamics model constraints satisfies the obstacle avoidance constraints and the lane constraints comprises:
determining an obstacle avoidance energy function in the obstacle avoidance constraint condition corresponding to each speed to be updated according to each speed to be updated;
if the value of the obstacle avoidance energy function is smaller than a first preset threshold value, determining that each speed to be updated meets the obstacle avoidance constraint condition;
determining whether each speed to be updated meets the lane constraint condition;
the determining an obstacle avoidance energy function in the obstacle avoidance constraint condition corresponding to each speed to be updated includes:
if the main vehicle is in a non-lane-changing state, determining an obstacle avoidance energy function enRep corresponding to the speed to be updated according to the following formula;
enRep＝ρrep×(v0×tsafe-min(s，sp))；
where ρ isrepIs a preset first weight, tsafeS is a first distance between the main vehicle and a front vehicle of the current lane at the next update time along the current lane direction for a preset safe time, s is a second distance between the main vehicle and the front vehicle of the current lane at the next update timepThe second distance between the main vehicle and a front vehicle of the current lane is a second distance after a preset time length along the direction of the current lane;
s＝p0+v0×Δt–(p1+v1×Δt)；
sp＝p0+v0×Δt×εp–(p1+v1×Δt×εp) (ii) a p0, p1 are the current positions of the host vehicle and the vehicle ahead of the current lane, v0 is the speed to be updated, v1 is the current vehicle speed of the vehicle ahead of the current lane, epsilonpIs a preset prediction step length;
if the main vehicle is in a lane change state, determining an obstacle avoidance energy function enRep corresponding to the speed to be updated according to the following formula;
enRep＝ρrep×(v0×tsafe-min(s，sp，st，stp))；
wherein s istIs a third distance, stpIs a fourth distance; the third distance is a distance between the host vehicle and a vehicle ahead of a target lane, and the fourth distance is a predicted distance between the host vehicle and the vehicle ahead of the target lane after a preset time period;
st＝p0+v0×Δt–(p2+v2×Δt)；
stp＝p0+v0×Δt×εp–(p2+v2×Δt×εp)；
wherein p0 and p2 are the current positions of the vehicles ahead of the main vehicle and the target lane, v0 is the speed to be updated, and v2 is the current vehicle speed of the vehicle ahead of the target lane.
4. The method according to claim 3, wherein if the host vehicle is in a lane change state, determining a speed direction energy function, a lane distance energy function and a lane direction energy function in the lane constraint condition corresponding to the speed to be updated according to each speed to be updated comprises:
if a first included angle between the main vehicle and a current lane where the main vehicle is located is larger than a preset first angle threshold, determining the speed direction energy function comprises:
determining a speed direction energy function enVel corresponding to the speed to be updated according to the following formula;
enVel＝ρvel×tan(|Δθ'|)；
where ρ isvelThe weight is a preset second weight, and delta theta' is the first included angle;
if the first included angle is smaller than the first angle threshold value, and a fifth distance between the main vehicle and a target lane to be entered by the main vehicle is larger than a preset second distance threshold value, the determining the lane distance energy function includes:
determining a lane distance energy function enLanePos corresponding to the speed to be updated according to the following formula;
enLanePos＝ρlanePos×slane×slane；
where ρ islanePosIs a preset third weight, slaneA fifth distance between the host vehicle and a target lane into which the host vehicle is to enter;
if the first included angle is smaller than the first preset threshold value, the distance between the main vehicle and the target lane is smaller than the second distance threshold value, and the second included angle between the main vehicle and the target lane direction is larger than a preset second angle threshold value, determining the lane direction energy function comprises:
determining a lane direction energy function enLaneDir corresponding to the speed to be updated according to the following formula;
enLaneDir＝ρlaneDir×tan(Δθ")；
where ρ islaneDirAnd in the preset fourth weight, the delta theta' is the second included angle.
5. The method according to claim 3, wherein if the host vehicle is in a non-lane-changing state, the determining a speed direction energy function, a lane distance energy function and a lane direction energy function in the lane constraint condition corresponding to the speed to be updated according to each speed to be updated comprises:
if the distance between the main vehicle and the current lane where the main vehicle is located is smaller than a preset second distance threshold, and a third included angle between the main vehicle and the current lane where the main vehicle is located is smaller than a preset first angle threshold, the determining the speed direction energy function includes:
determining a speed direction energy function enVel corresponding to the speed to be updated according to the following formula;
enVel＝ρvel×tan(|Δθ'|)；
where ρ isvelThe weight is a preset second weight, and delta theta' is the third included angle;
if the distance between the host vehicle and the current lane where the host vehicle is located is greater than the second distance threshold, the determining the lane distance energy function includes:
determining a lane distance energy function enLanePos corresponding to the speed to be updated according to the following formula;
enLanePos＝ρlanePos×slane×slane；
where ρ islanePosIs a preset third weight, slaneThe distance between the host vehicle and the current lane where the host vehicle is located;
if the distance between the host vehicle and the current lane where the host vehicle is located is smaller than the second distance threshold value, and the third included angle is larger than the first angle threshold value, determining the lane direction energy function includes:
determining a lane direction energy function enLaneDir corresponding to the speed to be updated according to the following formula;
enLaneDir＝ρlaneDir×tan(Δθ")；
where ρ islaneDirAnd delta theta' is the third included angle and is a preset fourth weight.
6. The method according to claim 4 or 5, wherein the determining whether each of the speeds to be updated satisfies the lane constraint condition comprises: and if the value of the speed direction energy function is smaller than a second preset threshold, the value of the lane distance energy function is smaller than a third preset threshold, and the value of the lane direction energy function is smaller than a fourth preset threshold, determining that each speed to be updated meets the lane constraint condition.
7. The method of claim 6, wherein after determining that each of the to-be-updated speeds satisfies the lane constraint, further comprising:
and searching the speed to be updated with the minimum sum of the obstacle avoidance energy function, the speed direction energy function, the lane distance energy function and the lane direction energy function from the speeds to be updated meeting the obstacle avoidance constraint condition, the lane constraint condition and the vehicle dynamic model constraint, and taking the speed to be updated as the speed of the main vehicle at the next updating moment.
8. The method according to claim 2, wherein the determining the speed direction change angle of each speed to be updated at the next updating time according to each speed to be updated comprises:
determining the speed direction change angle of the main vehicle at the next updating moment according to the wheel rotation angle, the wheel base and the speed to be updated of the main vehicle;
correspondingly, the determining whether the speed direction change angle of each speed to be updated at the next updating time is reasonable or not according to the preset relation between the speed and the speed direction change angle and the wheel rotation angle range of the main vehicle comprises:
determining whether the speed-direction change angle is within a wheel turning angle range of the host vehicle;
and if so, determining whether the speed direction change angle is reasonable or not according to the relation between the speed and the speed direction change angle.
9. The method according to claim 3, wherein before determining an obstacle avoidance energy function in the obstacle avoidance constraint condition corresponding to each of the to-be-updated speeds, the method further includes:
if the front vehicle exists in the current lane where the main vehicle is located, determining a first distance between the main vehicle and the front vehicle at the next updating moment along the current lane direction according to the speed to be updated of the main vehicle and the current speed of the front vehicle, and predicting a second distance between the main vehicle and the front vehicle along the current lane direction after a preset time;
and if the first distance and the second distance are greater than a preset safety distance, determining the obstacle avoidance energy function.
10. The method of claim 7, further comprising:
if the value of the obstacle avoidance energy function of the main vehicle is zero, determining a speed expected constraint function corresponding to the speed to be updated according to a preset expected speed and the speed to be updated of the main vehicle;
the searching for the speed to be updated with the minimum sum of the obstacle avoidance energy function, the speed direction energy function, the lane distance energy function and the lane direction energy function from the speeds to be updated which meet the obstacle avoidance constraint condition, the lane constraint condition and the vehicle dynamics model constraint includes:
and searching the speed to be updated with the minimum sum of the obstacle avoidance energy function, the speed direction energy function, the lane distance energy function, the lane direction energy function and the speed expectation constraint function from the speeds to be updated which meet the obstacle avoidance constraint condition, the lane constraint condition and the vehicle dynamic model constraint.
11. The method of any one of claims 1-5 and 8-10, further comprising:
determining whether the host vehicle is driving from a current lane in which the host vehicle is located to a target lane; the target lane is a lane adjacent to the current lane;
if so, determining that the main vehicle is in a lane changing state;
if not, determining that the main vehicle is in a non-lane-changing state.
12. The method of any one of claims 1-5 and 8-10, further comprising:
determining whether the main vehicle meets a preset lane-changing starting condition;
if the main vehicle meets the lane-changing starting condition, determining whether the main vehicle meets a preset lane-changing decision condition;
and if the main vehicle meets the lane change determining condition, controlling the main vehicle to change the lane from the current lane where the main vehicle is located to a target lane.
13. The method of claim 12, wherein the determining whether the host vehicle satisfies a preset lane-change launch condition comprises:
determining whether an adjacent lane exists in a current lane where the host vehicle is located;
if the current lane where the main vehicle is located has an adjacent lane, determining whether a front vehicle exists in the current lane;
if the current lane has the front vehicle, determining whether the front vehicle is in a non-lane-changing state;
and if the front vehicle is in a non-lane-changing state, determining that the main vehicle meets the lane-changing starting condition.
14. The method of claim 12, wherein the determining whether the host vehicle satisfies a preset lane change decision condition comprises:
determining whether a difference between a distance between the host vehicle and a preceding vehicle in the current lane and a distance between the host vehicle and a preceding vehicle in a target lane is less than a preset first distance threshold;
if so, determining whether the distance between the main vehicle and a front vehicle in the target lane along the direction of the target lane is greater than a preset safety distance;
if so, determining whether the distance between the main vehicle and a rear vehicle in the target lane along the direction of the target lane is greater than the safe distance; the target lane is a lane adjacent to the current lane;
and if so, determining that the main vehicle meets the lane change decision condition.
15. The method of any one of claims 1-5 and 8-10, further comprising:
constructing a road network structure according to preset road scene conditions; the road network structure comprises: a plurality of parallel lanes;
determining the number of vehicles and the initial positions of the vehicles in the road network structure according to preset traffic flow density;
wherein the information of the vehicle comprises at least one of: size of vehicle, acceleration range, wheel rotation angle range, desired speed, initial position, initial speed, initial direction.
16. The method according to any one of claims 1-5 and 8-10, wherein the speed to be updated, at which the obstacle avoidance constraint, the lane constraint and the vehicle dynamics model constraint are to be satisfied, is taken as the speed of the host vehicle at the next update time, further comprising:
determining the position of the host vehicle at the next update time according to the speed of the host vehicle at the next update time.
17. The method of claim 2, wherein determining the speed direction change angle of each speed to be updated at the next update time comprises:
determining a speed direction change angle delta theta of the speed to be updated at the next updating moment according to the following formula;
Δθ＝tan(Φ)/L×v0×Δt；
wherein Φ is a wheel rotation angle, L is a wheel base, v0 is the speed to be updated, and Δ t is the update time step.
18. The method of claim 10, wherein determining a velocity expectation constraint function based on a preset expectation velocity and a velocity of the host vehicle to be updated comprises:
determining a speed expectation constraint function envvelo corresponding to the speed to be updated according to the following formula;
enVelLimit＝ρvelLimit×|v0-vlimit|；
where ρ isvelLimitIs a preset fifth weight, vlimitV0 is the speed to be updated for the desired speed.
19. A vehicle speed determination apparatus, characterized by comprising:
the first determination module is used for determining at least one to-be-updated speed of the main vehicle according to at least one driving parameter of the main vehicle and a preset updating time step length;
the second determination module is used for determining whether the at least one speed to be updated has a speed to be updated which simultaneously meets preset obstacle avoidance constraint conditions, lane constraint conditions and vehicle dynamic model constraints; the speed direction change angle of the speed to be updated meeting the vehicle dynamic model constraint at the next updating moment is reasonable, and the speed direction change angle corresponding to the speed to be updated is determined according to the speed to be updated, the current wheel rotation angle, the wheelbase of the main vehicle and the updating time step; and the processing module is used for determining that the speed to be updated meeting the preset obstacle avoidance constraint condition, lane constraint condition and vehicle dynamic model constraint exists at the same time if the second determining module determines that the speed to be updated meeting the preset obstacle avoidance constraint condition, lane constraint condition and vehicle dynamic model constraint exists, and taking the speed to be updated meeting the obstacle avoidance constraint condition, lane constraint condition and vehicle dynamic model constraint as the speed of the main vehicle at the next updating moment.
20. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the method of any one of claims 1-18.
21. An electronic device, comprising:
a processor; and
a memory for storing executable instructions of the processor;
wherein the processor is configured to perform the method of any of claims 1-18 via execution of the executable instructions.
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