CN114995411A - Obstacle avoidance method and system for automatically driving automobile - Google Patents
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Abstract
The invention discloses an obstacle avoidance method and system for an automatic driving automobile, and the obstacle avoidance method for the automatic driving automobile comprises the following steps: determining obstacle avoidance constraint conditions according to obstacle avoidance conditions, and selecting an optimal obstacle avoidance path curve from a preset obstacle avoidance path curve database according to the obstacle avoidance constraint conditions, wherein the obstacle avoidance path curves in the obstacle avoidance path curve database have corresponding obstacle avoidance driving operation parameters; and operating the automobile to realize obstacle avoidance driving according to the obstacle avoidance driving operation parameters corresponding to the optimal obstacle avoidance path curve. The method can directly calculate the actual obstacle avoidance driving path without three steps of path planning, path smooth fitting and track tracking, and is simpler and more convenient to realize; the obtained obstacle avoidance path curve directly corresponds to driving operation parameters, so that the driving operation habit and the automobile driving track characteristic are better met, the lateral acceleration constraint condition is considered when the obstacle avoidance path curve is designed, and the lateral smoothness performance of the automobile during obstacle avoidance driving can be ensured.
Description
Technical Field
The invention relates to an automatic driving technology of an automobile, in particular to an obstacle avoidance method and system for an automatic driving automobile.
Background
The obstacle avoidance technology is a key technology of automatically driving the automobile, and the key of the automobile for realizing autonomous obstacle avoidance is reasonable path planning of an obstacle avoidance path. The meaning of path planning is: and determining an optimal or suboptimal path from the starting point to the end point under the specified evaluation index and constraint conditions. For the field of vehicle engineering, path planning refers to determining an optimal driving path from a starting point to a destination in a specified traffic route, so that an objective function obtains an optimal value (no collision, minimum driving distance, shortest time, congestion avoidance and the like) under a constraint condition.
The traditional obstacle avoidance path planning method comprises an artificial potential field method, a genetic algorithm, a fuzzy algorithm and the like. The traditional obstacle avoidance path planning method generally comprises the steps of firstly calculating an optimal obstacle avoidance path according to an obstacle model and distribution conditions, then carrying out geometric smooth fitting processing on the calculated optimal obstacle avoidance path to be used as an actual driving target path of an automobile, and finally adopting a track tracking control technology to control the actual driving track of the automobile to accord with the planned and fitted target path.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: aiming at the problems in the prior art, the invention provides an obstacle avoidance method and system for an automatic driving automobile, the actual obstacle avoidance driving path of the automobile can be directly calculated, three steps of path planning, path smooth fitting and track tracking are not needed like the traditional obstacle avoidance algorithm, and the method is simpler and more convenient compared with the traditional algorithm; the obstacle avoidance path curve obtained by calculation of the invention directly corresponds to the driving operation parameters, and is more in line with the driving operation habit and the characteristics of the automobile driving track.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
an obstacle avoidance method for an autonomous vehicle, comprising:
s1, determining obstacle avoidance constraint conditions according to obstacle avoidance conditions, and selecting an optimal obstacle avoidance path curve from a preset obstacle avoidance path curve database according to the obstacle avoidance constraint conditions, wherein the obstacle avoidance path curves in the obstacle avoidance path curve database have corresponding obstacle avoidance driving operation parameters;
and S2, controlling the automobile to realize obstacle avoidance driving according to the obstacle avoidance driving operation parameters corresponding to the optimal obstacle avoidance path curve.
Optionally, the obstacle avoidance path curve in the preset obstacle avoidance path curve database includes an obstacle avoidance segment, a driving segment and a returning segment, where the driving segment is a straight driving segment.
Optionally, the obstacle avoidance path curve in the preset obstacle avoidance path curve database is divided into two types, that is, an initial steering direction is counterclockwise and a clockwise direction, according to the difference of the initial steering direction, the two types of obstacle avoidance path curves are respectively composed of two parts, and a function expression of a curve of a first part of a driving track curve, that is, the initial steering direction is counterclockwise, is:
in the above formula, x (t), y (t) are coordinates of each point on the travel locus curve at time t, and t ∈ [0, t [ ] 1 ]，t 1 The time when the automobile runs on the curve of the first part is shown, v is the running speed of the automobile, L is the wheel base of the automobile, psi is the angular speed of the rotation of the automobile steering wheel, and t is a time parameter; the functional expression of the curve of the second part of the travel trajectory curve with the initial steering direction being anti-clockwise is:
in the above formula, x (t), y (t) are coordinates of each point on the travel locus curve at time t, and t ∈ [0, t [ ] 2 ]，t 2 Is the time the vehicle is traveling on the curve of the second portion; the functional expression of the curve of the first part of the travel trajectory curve with the initial steering direction clockwise is:
in the above formula, x (t), y (t) are coordinates of each point on the travel locus curve at time t, and t ∈ [0, t [ ] 1 ]，t 1 Is the time the vehicle is traveling on the curve of the first portion; the functional expression of the curve for the second portion of the travel path curve with the initial steering direction being clockwise is:
in the above formula, x (t), y (b)t) is the coordinate of each point on the travel track curve at the time t, and t belongs to [0, t ] 2 ]，t 2 The time the car is travelling on the curve of the second section.
Optionally, the obstacle avoidance path curve in the preset obstacle avoidance path curve database includes the following constraint conditions: condition 1, the absolute value of the lateral acceleration of the automobile in the obstacle avoidance driving process is not more than a set value, and the absolute value | a of the lateral acceleration of the curve of the first part 1 The expression of the calculation function of is | a 1 |＝|v 2 sin ψ t/L | absolute value of lateral acceleration | a of the curve of the second section 2 The expression of the calculation function of is | a 2 |＝|v 2 sinψ(t 1 -t)/L |; and 2, the absolute value | theta | of the heading angle of the automobile after the automobile finishes the curve driving of the second part meets the condition that the absolute value | theta | of the heading angle is smaller than a set value, and the calculation function expression of the absolute value | theta | of the heading angle is as follows:
optionally, the determining the obstacle avoidance constraint condition according to the obstacle avoidance condition in step S1 includes: the method comprises the following steps that 1, the automobile does not contact with an obstacle in the obstacle avoidance driving process; condition 2, the distance between the automobile and the obstacle in the driving process is as small as possible but not less than the set safe distance d of the obstacle 1 (ii) a Condition 3, the distance between the automobile and the road boundary in the driving process is not less than the set road boundary safety distance d 2 。
Optionally, the set barrier safety distance d 1 0.5m, the set road boundary safety distance d 2 Is 0.2 m.
Optionally, the selecting an optimal obstacle avoidance path curve from a preset obstacle avoidance path curve database according to the obstacle avoidance constraint condition in step S1 includes:
s1.1, defining the initial driving direction of the automobile as the positive x direction, and then, defining the left side of the automobile as the positive y direction perpendicular to the positive x direction; determining the initial steering direction of the automobile according to the obstacle avoidance space between the obstacle and the two side boundaries of the road, and defining D 1 And D 2 For obstacles away from both sides of roadMinimum distance of boundary, if D is satisfied 1 >D 2 Then get D 1 The side is the obstacle avoidance driving side and needs to satisfy D 1 ≥d 1 +d 2 + W and W are the width of the automobile, so that the initial steering direction type of the path curve of the obstacle avoidance section is determined;
s1.2, based on the determination of the initial steering direction type of the obstacle avoidance section path curve, determining an obstacle avoidance section, a driving-away section and a return section of the obstacle avoidance section path curve according to the following modes:
aiming at the obstacle avoidance section: obstacle avoidance amplitude y in y direction BO Initially selecting an obstacle avoidance section path curve in an obstacle avoidance section path curve of an initial steering direction type for control parameters, wherein the y-direction obstacle avoidance amplitude y BO The difference between the ending position point B of the obstacle avoidance section and the initial position point O of the obstacle avoidance section is the y-direction coordinate; defining a point P as a point of an obstacle closest to a road boundary on an automobile obstacle avoidance driving side, wherein the initially selected constraint conditions of an obstacle avoidance path curve are as follows: y is BO ≥0.5m+y PO And initially selecting constraint y BO As small as possible, where y PO The difference of the Y coordinate of the P point and the initial position point O of the obstacle avoidance section is obtained; according to the running speed v and the primary selection constraint condition y BO Initially selecting an obstacle avoidance section path curve in an obstacle avoidance path curve database, and enabling psi and t corresponding to the initially selected obstacle avoidance section path curve 1 、t 2 As a preliminarily selected driving operation parameter of the obstacle avoidance section of the automobile, wherein t 1 Time of travel of the vehicle on the first part of the curve, t 2 Psi is the angular velocity of the turning of the steerable wheels of the vehicle for the time the vehicle is traveling on the curve of the second portion; defining the point Q as the closest point to the automobile in the x direction on the barrier according to x QO ＝x BO +0.5m determines the x-direction position x of the O point of the initial obstacle avoidance point QO Wherein x is BO Obtaining the x coordinate difference between the ending position point B and the initial position point O of the obstacle avoidance section in the initially selected obstacle avoidance section path curve;
aiming at a driving-off segment: driving length L of straight line section corresponding to driving-off section L Determined according to the following formula: l is L ＝L v +L o +1m, travel time t of the drive-off segment 0 ＝L L V, wherein L v Is the length of the car, L o Is the x-direction maximum of the obstacleLength, v is vehicle speed;
for the homing segment: the driving operation parameters of the return section are according to-psi and t 1 、t 2 Determining and determining a driving path curve of the return section according to the driving operation parameters;
s1.3, verifying the minimum distance d between the complete obstacle avoidance path curve and the obstacle o Minimum distance d from road boundary b If satisfy d o ≥d 1 、d b ≥d 2 Driving according to the determined obstacle avoidance path curve; if not, increasing the primary selection constraint y BO Skipping to step S1.2 to reselect the obstacle avoidance path curve.
In addition, the invention also provides an obstacle avoidance system for an autonomous vehicle, which comprises a microprocessor and a memory which are connected with each other, wherein the microprocessor is programmed or configured to execute the steps of the obstacle avoidance method for the autonomous vehicle.
In addition, the invention also provides an automatic driving automobile which comprises an automobile body and an automatic driving control system arranged in the automobile body, wherein the automatic driving control system comprises a microprocessor and a memory which are connected with each other, and the microprocessor is programmed or configured to execute the steps of the obstacle avoiding method for the automatic driving automobile.
Furthermore, the present invention also provides a computer-readable storage medium having stored thereon a computer program for being programmed or configured by a microprocessor to carry out the steps of the method for obstacle avoidance for an autonomous vehicle.
Compared with the prior art, the invention mainly has the following advantages:
1. by adopting the calculation method, the steering control parameters are directly adopted as the input conditions when the obstacle avoidance path is calculated, and the obstacle is only used as the constraint condition of the obstacle avoidance, so that the obstacle avoidance path obtained by adopting the calculation method accords with the actual driving condition of the automobile without performing additional fitting and smoothing processing on the calculation result of the obstacle avoidance path.
2. Because the obstacle avoidance path obtained by calculation corresponds to the steering control parameter, the automobile can be controlled to realize obstacle avoidance driving by directly adopting the corresponding steering control parameter without additionally adopting a track tracking control technology.
Drawings
FIG. 1 is a schematic diagram of a basic process of an embodiment of the present invention.
Fig. 2 is a schematic diagram of an obstacle avoidance path curve according to an embodiment of the present invention.
Fig. 3 is a graph of an obstacle avoidance path at different vehicle speeds v, where ψ is 1.5rad/s, according to an embodiment of the present invention.
Fig. 4 is a graph of an obstacle avoidance path at different vehicle speeds v, where ψ is 1rad/s, according to an embodiment of the present invention.
Fig. 5 is a graph of an obstacle avoidance path at different vehicle speeds v, where ψ is 0.5rad/s, according to an embodiment of the present invention.
Fig. 6 is a schematic diagram of an actual obstacle avoidance condition according to a first embodiment of the present invention.
Detailed Description
The first embodiment is as follows:
as shown in fig. 1, the obstacle avoidance method for an autonomous vehicle of the present embodiment includes:
s1, determining obstacle avoidance constraint conditions according to obstacle avoidance conditions, and selecting an optimal obstacle avoidance path curve from a preset obstacle avoidance path curve database according to the obstacle avoidance constraint conditions, wherein the obstacle avoidance path curves in the obstacle avoidance path curve database have corresponding obstacle avoidance driving operation parameters;
and S2, controlling the automobile to realize obstacle avoidance driving according to the obstacle avoidance driving operation parameters corresponding to the optimal obstacle avoidance path curve.
The obstacle avoidance path curve database comprises a plurality of obstacle avoidance path curves, and each obstacle avoidance path curve has corresponding obstacle avoidance driving operation parameters. The generation mode of the obstacle avoidance path curve database is as follows: firstly, each specific obstacle avoidance driving operation parameter is arranged and combined to form different sets of obstacle avoidance driving operation parameters, then, a corresponding obstacle avoidance path curve is generated for each set of obstacle avoidance driving operation parameters, and finally, all obstacle avoidance path curves are added into a database, so that an obstacle avoidance path curve database can be obtained.
The obstacle avoidance driving operation parameters refer to operation parameters related to obstacle avoidance driving, can be determined according to actual driving requirements of the automobile, generally speaking, can contain data such as steering parameters and automobile speed, and a large number of different obstacle avoidance driving path curves can be obtained based on the data such as different steering parameters and automobile speeds, and the obstacle avoidance driving path curves correspond to the steering operation parameters one to one. When the automobile runs in an obstacle avoidance mode, the optimal obstacle avoidance running path curve is selected according to the preset control logic calculation, and the steering action of the automobile is controlled by adopting the driving operation parameters corresponding to the selected optimal path curve, so that the obstacle avoidance running is realized.
As shown in fig. 2, the obstacle avoidance path curve in the preset obstacle avoidance path curve database in this embodiment includes an obstacle avoidance segment, a driving segment and a returning segment, where the driving segment is a straight driving segment. In the figure, the automobile is abstracted into a rectangular structure, and the four corners of the automobile are respectively marked as a, b, c and d. The obstacle avoidance section is a curve between the initial position of the automobile and the obstacle avoidance completion position; the return section is a curve between the end position of the driving-away section and the return completion position.
In this embodiment, the obstacle avoidance path curve in the preset obstacle avoidance path curve database is divided into two types, namely, an anticlockwise type and a clockwise type, according to the difference of the initial turning direction, the two types of obstacle avoidance path curves are respectively composed of two parts, and the function expression of the curve of the first part of the driving track curve with the initial turning direction being the anticlockwise direction is as follows:
in the above formula, x (t), y (t) are coordinates of each point on the travel locus curve at time t, and t ∈ [0, t [ ] 1 ]，t 1 The time when the automobile runs on the curve of the first part is shown, v is the running speed of the automobile, L is the wheel base of the automobile, psi is the angular speed of the rotation of the automobile steering wheel, and t is a time parameter; the functional expression of the curve of the second part of the travel trajectory curve with the initial steering direction in the counterclockwise direction is：
In the above formula, x (t), y (t) are coordinates of each point on the travel locus curve at time t, and t ∈ [0, t [ ] 2 ]，t 2 Is the time the vehicle is traveling on the curve of the second portion; the functional expression of the curve of the first part of the travel trajectory curve with the initial steering direction clockwise is:
in the above formula, x (t), y (t) are coordinates of each point on the travel locus curve at time t, and t ∈ [0, t [ ] 1 ]，t 1 Is the time the car is driving on the curve of the first part; the functional expression of the curve of the second part of the travel trajectory curve with the initial steering direction clockwise is:
in the above formula, x (t), y (t) are coordinates of each point on the travel locus curve at time t, and t ∈ [0, t [ ] 2 ]，t 2 The time the car is travelling on the curve of the second section.
Correspondingly, the obstacle avoidance driving operation parameters in the embodiment include a steering wheel angular velocity parameter psi, a turning direction of the steering wheel, and a time t for the automobile to travel on the curve of the first portion 1 The time t for the vehicle to travel on the curve of the second section 2 And vehicle speed v. FIG. 3, FIG. 4, and FIG. 5 represent the obstacle avoidance driving trace curves of the vehicle with the wheelbase of 2.5m under different steering wheel steering angular velocities ψ and different vehicle speeds v, respectively, wherein the obstacle avoidance driving time t is t 1 ＝0.4s，t 2 0.935 s. The left half part of the curve represents the obstacle avoidance driving working condition (obstacle avoidance section) of the automobile, the right half part represents the working condition (return section) that the automobile drives back to the original driving path after the obstacle avoidance is finished,the drive-off segment is a straight line segment and is therefore omitted from the above figures.
In this embodiment, the determining the obstacle avoidance constraint conditions according to the obstacle avoidance conditions in step S1 includes: the method comprises the following steps that 1, the automobile does not contact with an obstacle in the obstacle avoidance driving process; condition 2, the distance between the automobile and the obstacle in the driving process is as small as possible but not less than the set safe distance d of the obstacle 1 (ii) a Condition 3, the distance between the automobile and the road boundary in the driving process is not less than the set road boundary safety distance d 2 . Set barrier safety distance d 1 Safe distance d from road boundary 2 The setting can be carried out according to the actual obstacle avoidance working condition. Fig. 6 is a schematic diagram of an actual obstacle avoidance condition in this embodiment, where the units of dimensions in the diagram are all mm, for example, the length of an automobile is 4000mm, the width is 1800mm, and the remaining dimensions are labeled in the diagram. In this embodiment, the set safety distance d of the obstacle is set for the actual obstacle avoidance condition 1 0.5m, road boundary safety distance d 2 The average particle size of the particles is 0.2m,
in this embodiment, the selecting, according to the obstacle avoidance constraint condition, an optimal obstacle avoidance path curve from a preset obstacle avoidance path curve database in step S1 includes:
s1.1, defining the initial driving direction of the automobile as the positive x direction, and then, defining the left side of the automobile as the positive y direction perpendicular to the positive x direction; determining the initial steering direction of the automobile according to the obstacle avoidance space between the obstacle and the two side boundaries of the road, and defining D 1 And D 2 The minimum distance between the obstacle and the road boundaries on two sides is defined as D 1 >D 2 Then get D 1 The side is the obstacle avoidance driving side and needs to satisfy D 1 ≥d 1 +d 2 + W, W is the width of the automobile, so as to determine the initial steering direction type of the path curve of the obstacle avoidance section;
s1.2, based on the initial steering direction type of the obstacle avoidance section path curve, determining an obstacle avoidance section, a driving away section and a return section of the obstacle avoidance section path curve according to the following modes:
aiming at the obstacle avoidance section: obstacle avoidance amplitude y in y direction BO Initially selecting an obstacle avoidance section path curve in an obstacle avoidance section path curve of an initial steering direction type for control parameters, wherein the y-direction obstacle avoidance amplitude y BO The difference between the ending position point B of the obstacle avoidance section and the initial position point O of the obstacle avoidance section is the y-direction coordinate; defining a point P as a point of an obstacle closest to a road boundary on an automobile obstacle avoidance driving side, wherein the initially selected constraint conditions of an obstacle avoidance path curve are as follows: y is BO ≥0.5m+y PO And initially selecting constraint y BO As small as possible, where y PO The difference of the Y coordinate of the point P and the initial position point O of the obstacle avoidance section is obtained; according to the running speed v and the primary selection constraint condition y BO Initially selecting an obstacle avoidance section path curve in an obstacle avoidance path curve database, and enabling psi and t corresponding to the initially selected obstacle avoidance section path curve 1 、t 2 As a preliminarily selected driving operation parameter of the obstacle avoidance section of the automobile, wherein t 1 Time of travel of the vehicle on the first part of the curve, t 2 Psi is the angular velocity of the turning of the steerable wheels of the vehicle for the time the vehicle is traveling on the curve of the second portion; defining the point Q as the closest point to the automobile in the x direction on the barrier according to x QO ＝x BO +0.5m determines the x-direction position x of the obstacle avoidance initial point O point QO Wherein x is BO Obtaining the x coordinate difference between the ending position point B and the initial position point O of the obstacle avoidance section in the initially selected obstacle avoidance section path curve; in this embodiment, the initial steering direction of the obstacle avoidance segment is counterclockwise, the corresponding steering operation parameter ψ is 0.63rad/s, and the steering operation time is counterclockwise (t) 1 )0.47s, clockwise (t) 2 )1.12s。
Aiming at a drive-off segment: straight line section running length L corresponding to driving-off section L Determined according to the following formula: l is L ＝L v +L o +1m, travel time t of the drive-off segment 0 ＝L L V, wherein L v Is the length of the car, L o The maximum length of the obstacle in the x direction, and v is the vehicle speed; the driving-away section has the function that the automobile and the obstacle have certain lengths, so that the automobile needs to continue to linearly drive for a certain distance after obstacle avoidance operation, and the driving-away section length is calculated according to the automobile length, the obstacle length and the obstacle avoidance distance, in the embodiment, the driving-away section length is 6m, and the driving speed of the automobile is 5m/s, so that the driving time of the automobile in the driving-away section is 1.2s, and the steering wheel of the automobile is in a aligning state.
For the homing segment: the driving operation parameters of the return section are according to-psi and t 1 、t 2 Determining and determining a driving path curve of the return section according to the driving operation parameters; in this embodiment, the initial steering direction of the return segment is clockwise, the corresponding steering operation parameter ψ is 0.63rad/s, and the steering operation time is clockwise (t) 1 )0.47s, counterclockwise (t) 2 )1.12s。
S1.3, verifying the minimum distance d between the complete obstacle avoidance path curve and the obstacle o Minimum distance d from road boundary b If satisfy d o ≥d 1 、d b ≥d 2 Driving according to the determined obstacle avoidance path curve; if not, increasing the primary selection constraint y BO Skipping step S1.2 to reselect the obstacle avoidance path curve.
Finally, based on the obstacle avoidance constraint conditions (conditions 1 to 3) determined according to the obstacle avoidance conditions in step S1, calculating the steering wheel angular velocity parameter psi corresponding to the selected optimal obstacle avoidance path curve, the rotation direction of the steering wheel, and the time t for the vehicle to travel on the curve of the obstacle avoidance section 1 、t 2 The time t for the vehicle to travel on the curve of the return section 1 、t 2 And the automobile speed v can be controlled to realize obstacle avoidance driving.
In addition, the present embodiment also provides an obstacle avoidance system for an autonomous vehicle, including a microprocessor and a memory connected to each other, where the microprocessor is programmed or configured to execute the steps of the obstacle avoidance method for an autonomous vehicle.
In addition, the embodiment also provides an automatic driving automobile, which comprises an automobile body and an automatic driving control system arranged in the automobile body, wherein the automatic driving control system comprises a microprocessor and a memory which are connected with each other, and the microprocessor is programmed or configured to execute the steps of the obstacle avoidance method for the automatic driving automobile.
Furthermore, the present embodiment also provides a computer-readable storage medium, in which a computer program is stored, the computer program being programmed or configured by a microprocessor to execute the steps of the above-mentioned obstacle avoidance method for automatically driving a vehicle.
Example two:
the present embodiment is substantially the same as the first embodiment, and the main differences are as follows: in this embodiment, when the obstacle avoidance path curve database is generated, the obstacle avoidance path curve includes a preset constraint condition. The generation mode of the obstacle avoidance path curve database is as follows: firstly, each specific obstacle avoidance driving operation parameter is arranged and combined to form a set of different obstacle avoidance driving operation parameters, constraint conditions of an obstacle avoidance path curve are preset, then a corresponding obstacle avoidance path curve is generated for each set of obstacle avoidance driving operation parameters, and finally all obstacle avoidance path curves meeting the constraint conditions are added into a database, so that an obstacle avoidance path curve database can be obtained.
In this embodiment, the obstacle avoidance path curve in the preset obstacle avoidance path curve database includes the following constraint conditions:
And 2, the absolute value | theta | of the heading angle of the automobile after the automobile finishes the curve driving of the second part meets the condition that the absolute value | theta | of the heading angle is smaller than a set value, and the calculation function expression of the absolute value | theta | of the heading angle is as follows:
when an obstacle avoidance path curve is designed, the lateral smoothness of the automobile can be directly guaranteed when the obstacle avoidance driving is carried out by considering the constraint condition of the lateral acceleration.
As an alternative embodiment, the condition 1 in this embodiment is that the absolute value of the lateral acceleration is not more than 4m/s 2 The condition 2 is that the absolute value of the heading angle | θ | satisfies less than 1 °.
In addition, the present embodiment also provides an obstacle avoidance system for an autonomous vehicle, including a microprocessor and a memory connected to each other, where the microprocessor is programmed or configured to execute the steps of the obstacle avoidance method for an autonomous vehicle.
In addition, the present embodiment also provides an autonomous driving vehicle, which includes a vehicle body and an autonomous driving control system disposed in the vehicle body, where the autonomous driving control system includes a microprocessor and a memory connected to each other, and the microprocessor is programmed or configured to execute the steps of the above-mentioned obstacle avoidance method for the autonomous driving vehicle.
Furthermore, the present embodiment also provides a computer-readable storage medium, in which a computer program is stored, the computer program being programmed or configured by a microprocessor to execute the steps of the above-mentioned obstacle avoidance method for automatically driving a vehicle.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-readable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.
Claims (10)
1. An obstacle avoidance method for an autonomous vehicle, comprising:
s1, determining obstacle avoidance constraint conditions according to obstacle avoidance conditions, and selecting an optimal obstacle avoidance path curve from a preset obstacle avoidance path curve database according to the obstacle avoidance constraint conditions, wherein the obstacle avoidance path curves in the obstacle avoidance path curve database have corresponding obstacle avoidance driving operation parameters;
and S2, controlling the automobile to realize obstacle avoidance driving according to the obstacle avoidance driving operation parameters corresponding to the optimal obstacle avoidance path curve.
2. An obstacle avoidance method for an autonomous vehicle according to claim 1, wherein the obstacle avoidance path curve in the preset obstacle avoidance path curve database includes an obstacle avoidance section, a drive-off section and a return section, wherein the drive-off section is a straight-line drive section.
3. The obstacle avoidance method for the autonomous driving vehicle as claimed in claim 2, wherein the obstacle avoidance path curves in the preset obstacle avoidance path curve database are divided into two types of the initial turning direction being the counterclockwise direction and the clockwise direction according to the difference of the initial turning direction, the two types of the obstacle avoidance path curves are respectively composed of two parts, and the functional expression of the curve of the first part of the driving trajectory curve with the initial turning direction being the counterclockwise direction is:
in the above formula, x (t), y (t) are coordinates of each point on the travel locus curve at time t, and t ∈ [0, t [ ] 1 ]，t 1 The time when the automobile runs on the curve of the first part is shown, v is the running speed of the automobile, L is the wheel base of the automobile, psi is the angular speed of the rotation of the automobile steering wheel, and t is a time parameter; the functional expression of the curve of the second part of the travel trajectory curve with the initial steering direction being anti-clockwise is:
in the above formula, x (t), y (t) are coordinates of each point on the travel locus curve at time t, and t ∈ [0, t [ ] 2 ]，t 2 Is the time the car is driving on the curve of the second portion; the functional expression of the curve of the first part of the travel trajectory curve with the initial steering direction clockwise is:
in the above formula, x (t), y (t) are coordinates of each point on the travel locus curve at time t, t ∈ [0,t 1 ]，t 1 is the time the vehicle is traveling on the curve of the first portion; the functional expression of the curve of the second part of the travel trajectory curve with the initial steering direction clockwise is:
in the above formula, x (t), y (t) are coordinates of each point on the travel locus curve at time t, and t ∈ [0, t [ ] 2 ]，t 2 The time the car is travelling on the curve of the second section.
4. An obstacle avoidance method for an autonomous vehicle according to claim 3, characterized in that the obstacle avoidance path curves in the preset obstacle avoidance path curve database include the following constraint conditions: condition 1, the absolute value of the lateral acceleration of the automobile in the obstacle avoidance driving process is not more than a set value, and the absolute value | a of the lateral acceleration of the curve of the first part 1 The expression of the calculation function of is | a 1 |＝|v 2 sin ψ t/L | absolute value of lateral acceleration | a of the curve of the second section 2 The expression of the calculation function of is | a 2 |＝|v 2 sinψ(t 1 -t)/L |; and 2, the absolute value | theta | of the heading angle of the automobile after the automobile finishes the curve driving of the second part meets the condition that the absolute value | theta | of the heading angle is smaller than a set value, and the calculation function expression of the absolute value | theta | of the heading angle is as follows:
5. an obstacle avoidance method for an autonomous vehicle according to claim 1, wherein the determining of the obstacle avoidance constraint conditions according to the obstacle avoidance conditions in step S1 includes: the method comprises the following steps that 1, the automobile does not contact with an obstacle in the obstacle avoidance driving process; condition 2, the distance between the automobile and the obstacle in the driving process is as small as possible but not less than the set safe distance d of the obstacle 1 (ii) a Condition 3, the distance between the automobile and the road boundary in the driving process is not less than the set road edgeBoundary safety distance d 2 。
6. An obstacle avoidance method for an autonomous vehicle according to claim 5, characterized in that said set obstacle safety distance d 1 0.5m, the set road boundary safety distance d 2 Is 0.2 m.
7. An obstacle avoidance method for an autonomous vehicle according to claim 5, wherein the step S1 of selecting an optimal obstacle avoidance path curve from a preset obstacle avoidance path curve database according to the obstacle avoidance constraint condition includes:
s1.1, defining the initial driving direction of the automobile as the positive x direction, and then, defining the left side of the automobile as the positive y direction perpendicular to the positive x direction; determining the initial steering direction of the automobile according to the obstacle avoidance space between the obstacle and the two side boundaries of the road, and defining D 1 And D 2 The minimum distance between the barrier and the road boundaries at two sides is defined as D 1 >D 2 Then get D 1 The side is the obstacle avoidance driving side and needs to satisfy D 1 ≥d 1 +d 2 + W, W is the width of the automobile, so as to determine the initial steering direction type of the path curve of the obstacle avoidance section;
s1.2, based on the initial steering direction type of the obstacle avoidance section path curve, determining an obstacle avoidance section, a driving away section and a return section of the obstacle avoidance section path curve according to the following modes:
aiming at the obstacle avoidance section: obstacle avoidance amplitude y in y direction BO Initially selecting an obstacle avoidance section path curve in an obstacle avoidance section path curve of an initial steering direction type for control parameters, wherein the y-direction obstacle avoidance amplitude y BO The difference between the ending position point B of the obstacle avoidance section and the initial position point O of the obstacle avoidance section is the y-direction coordinate; defining a point P as a point of an obstacle closest to a road boundary on an automobile obstacle avoidance driving side, wherein the initially selected constraint conditions of an obstacle avoidance path curve are as follows: y is BO ≥0.5m+y PO And initially selecting constraint y BO As small as possible, where y PO The difference of the Y coordinate of the P point and the initial position point O of the obstacle avoidance section is obtained; according to the running speed v and the primary selection constraint condition y BO Initially selected in the obstacle avoidance path curve databaseThe path curve of the obstacle avoidance section is obtained by selecting psi and t corresponding to the initially selected path curve of the obstacle avoidance section 1 、t 2 As a preliminarily selected driving operation parameter of the obstacle avoidance section of the automobile, wherein t 1 Time of travel of the vehicle on the first part of the curve, t 2 Psi is the angular velocity of the turning of the steerable wheels of the vehicle for the time the vehicle is traveling on the curve of the second portion; defining the point Q as the closest point to the automobile in the x direction on the barrier according to x QO ＝x BO +0.5m determines the x-direction position x of the obstacle avoidance initial point O point QO Wherein x is BO Obtaining the x coordinate difference between the ending position point B and the initial position point O of the obstacle avoidance section in the initially selected obstacle avoidance section path curve;
aiming at a driving-off segment: straight line section running length L corresponding to driving-off section L Determined according to the following formula: l is a radical of an alcohol L ＝L v +L o +1m, travel time t of the drive-off segment 0 ＝L L V, wherein L v Is the length of the car, L o The maximum length of the obstacle in the x direction, and v is the vehicle speed;
for the homing segment: the driving operation parameters of the return section are according to-psi and t 1 、t 2 Determining and determining a driving path curve of the return section according to the driving operation parameters;
s1.3, verifying the minimum distance d between the complete obstacle avoidance path curve and the obstacle o Minimum distance d from road boundary b If satisfy d o ≥d 1 、d b ≥d 2 Driving according to the determined obstacle avoidance path curve; if not, increasing the primary selection constraint y BO Skipping to step S1.2 to reselect the obstacle avoidance path curve.
8. An obstacle avoidance system for an autonomous vehicle, comprising a microprocessor and a memory connected to each other, characterized in that the microprocessor is programmed or configured to perform the steps of the obstacle avoidance method for an autonomous vehicle of any of claims 1 to 7.
9. An autonomous vehicle comprising a vehicle body and an autonomous driving control system provided in the vehicle body, the autonomous driving control system comprising a microprocessor and a memory connected to each other, characterized in that the microprocessor is programmed or configured to perform the steps of the method of any one of claims 1 to 7 for avoiding obstacles for an autonomous vehicle.
10. A computer-readable storage medium, in which a computer program is stored, wherein the computer program is adapted to be programmed or configured by a microprocessor to perform the steps of the method for obstacle avoidance for an autonomous vehicle as claimed in any of claims 1 to 7.
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| CN117689022A (en) * | 2024-02-04 | 2024-03-12 | 江苏未来网络集团有限公司 | Determination method of optimal rule base for real-time navigation of clinical exploration robot |
| CN117689022B (en) * | 2024-02-04 | 2024-05-03 | 江苏未来网络集团有限公司 | Determination method of optimal rule base for real-time navigation of clinical exploration robot |
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Application publication date: 20220902 |