CN116061933A - Vehicle speed planning method and device based on speed limiting information and domain controller - Google Patents

Vehicle speed planning method and device based on speed limiting information and domain controller Download PDF

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Publication number
CN116061933A
CN116061933A CN202310333457.3A CN202310333457A CN116061933A CN 116061933 A CN116061933 A CN 116061933A CN 202310333457 A CN202310333457 A CN 202310333457A CN 116061933 A CN116061933 A CN 116061933A
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speed
vehicle
speed limit
acceleration
planning
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CN116061933B (en
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彭东亮
胡文彪
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Shenzhen Haixing Zhijia Technology Co Ltd
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Shenzhen Haixing Zhijia Technology Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units, or advanced driver assistance systems for ensuring comfort, stability and safety or drive control systems for propelling or retarding the vehicle
    • B60W30/14—Adaptive cruise control
    • B60W30/143—Speed control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units, or advanced driver assistance systems for ensuring comfort, stability and safety or drive control systems for propelling or retarding the vehicle
    • B60W30/14—Adaptive cruise control
    • B60W30/143—Speed control
    • B60W30/146—Speed limiting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
    • B60W40/02—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to ambient conditions
    • B60W40/04—Traffic conditions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2552/00—Input parameters relating to infrastructure
    • B60W2552/50—Barriers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2554/00—Input parameters relating to objects
    • B60W2554/20—Static objects
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2554/00—Input parameters relating to objects
    • B60W2554/40—Dynamic objects, e.g. animals, windblown objects
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Abstract

The invention discloses a vehicle speed planning method and device based on speed limiting information and a domain controller, wherein the method comprises the following steps: a plurality of route points are arranged on a preset length section of a front route of the vehicle at equal intervals; assigning an initial speed limit value to each path point based on the speed limit requirement information; updating the initial speed limit value of each path point based on the obstacle information to obtain the latest speed limit value of each path point; generating a speed limit curve with speed limit values continuously changing along with the distance extension on a road section with a preset length through the latest speed limit values of all the path points; planning the acceleration and the speed of the vehicle in a preset time period in the future through a speed limiting curve; after the current speed planning period, returning to the step of setting a plurality of path points on the preset length section of the front path of the vehicle at equal intervals, and entering the next speed planning period. The technical scheme provided by the invention solves the problem of drastic change of the vehicle speed during vehicle speed planning, and further improves the comfort level of automatic driving of the vehicle.

Description

Vehicle speed planning method and device based on speed limiting information and domain controller
Technical Field
The invention relates to the field of automatic driving, in particular to a vehicle speed planning method and device based on speed limiting information and a domain controller.
Background
The automatic driving of the vehicle is beneficial to improving road safety, relieving manpower shortage and promoting energy conservation and environmental protection. Trajectory planning is one of the core services of vehicle autopilot, and is divided into path planning and speed planning. The path planning aims at generating a series of points so that the vehicle can smoothly move from the current position to the target position. The speed planning gives corresponding speed, acceleration and arrival time to each point on the basis of path planning, so that the vehicle can arrive at the target position as soon as possible under the requirements of safety, kinematics and the like. Speed planning often requires the completion of vehicle start, cruise, follow, obstacle avoidance, stop, etc.
Currently, for vehicle speed planning, the speed of a vehicle is usually planned in combination with the speed limiting requirement of a path segment and various obstacles appearing on the path, and the speed planning is usually aimed at not colliding with the obstacles or reaching an end point on time. However, the speed planning method does not fully consider the speed change degree of the automobile, only one speed is considered to be generated in the current speed planning period, the speed can meet the requirement of reaching an end point target or not colliding with an obstacle target in a specified time, if the emergency situation is more or the speed limiting requirement is too fast in change on road conditions, the speed change degree of each speed planning period is larger, the speed change of the automobile is fierce and frequent, and the experience of drivers and passengers is poor.
Disclosure of Invention
In view of the above, the embodiment of the invention provides a vehicle speed planning method, device and domain controller based on speed limiting information, which solve the problem of drastic vehicle speed change during vehicle speed planning on the basis of the current speed planning technology, and further improve the comfort level of automatic driving of the vehicle.
According to a first aspect, an embodiment of the present invention provides a vehicle speed planning method based on speed limit information, the method including: a plurality of route points are arranged on a preset length section of a front route of the vehicle at equal intervals; the speed limiting requirement information of the current path is read, and initial speed limiting values are given to all path points based on the speed limiting requirement information; acquiring barrier information in front of the vehicle, and updating initial speed limit values of all path points based on the barrier information to obtain the latest speed limit values of all the path points; generating a speed limit curve with speed limit values continuously changing along with the distance extension on the preset length road section through the latest speed limit values of all the path points; comprehensively planning the acceleration and the speed of the vehicle in a preset time period in the future so as to change the speed of the vehicle in the preset time period in the future according to the speed limiting curve; and after the current speed planning period, returning to the step of arranging a plurality of path points on the preset length section of the front path of the vehicle at equal intervals, and entering the next speed planning period.
Optionally, updating the initial speed limit value of each path point based on the obstacle information to obtain the latest speed limit value of each path point, including: when the obstacle information indicates that the front of the vehicle has a static obstacle, calculating the latest speed limit value corresponding to each path point capable of enabling the vehicle to stop at a first preset distance position in front of the static obstacle; when the obstacle information indicates that a traveling obstacle passing through a path of the vehicle exists in front of the vehicle, estimating traveling collision points of the vehicle and the traveling obstacle, and calculating the latest speed limit value of each path point in front of the vehicle by taking the traveling collision points as static obstacles; when the obstacle information indicates that a reverse obstacle exists in front of the vehicle, estimating a reverse collision point of the vehicle and the reverse obstacle, and calculating the latest speed limit value of each path point in front of the vehicle by taking the reverse collision point as a static obstacle; when the obstacle information indicates that the front of the vehicle has a vehicle following obstacle needing to follow the vehicle, determining a minimum vehicle following distance and a maximum vehicle following distance; when the distance between the vehicle and the following obstacle is between the minimum following distance and the maximum following distance, calculating the latest speed limit value of each path point in front of the vehicle by the following method
Figure SMS_1
In the method, in the process of the invention,
Figure SMS_2
for a preset maximum deceleration of the vehicle during normal driving,/->
Figure SMS_3
The distance from the waypoint to the following obstacle for which the current participation calculates the latest speed limit value,v follow equal to the travel speed of the following obstacle; when the distance between the vehicle and the following obstacle is smaller than the minimum following distance, calculating the latest speed limit value of each path point in front of the vehicle according to the following formula
Figure SMS_4
In the method, in the process of the invention,c times is a preset scaling parameter greater than 1; when the distance between the vehicle and the following obstacle is greater than the maximum following distance, calculating the latest speed limit value of each path point in front of the vehicle by adopting the following formula
Figure SMS_5
In the method, in the process of the invention,
Figure SMS_6
representing the maximum following distance.
Optionally, estimating the traveling collision point of the host vehicle and the traveling obstacle includes: estimating each arrival time when the vehicle arrives at any position in front at the current speed at constant speed; based on the running track of the passing obstacle, starting from the current position of the vehicle, testing whether the vehicle collides with the passing obstacle at a certain position in front one by one, and taking the first collision position obtained by testing as the passing collision point; wherein the steps of each test include: extracting target arrival time of the vehicle reaching the current test position from each arrival time; if the passing obstacle passes the current test position in a preset second before and after the target arrival time, taking the current test position as a collision position; and if the distance between the passing obstacle and the current test position at the target arrival time is within a second preset distance, taking the current test position as a collision position.
Optionally, the generating the speed limit curve with the speed limit continuously changing along with the distance extension on the preset length road section by the latest speed limit value of each path point includes: taking the extending distance of the road section with the preset length as a horizontal axis and taking the latest speed limiting value as a vertical axis, and generating a speed limiting curve based on the latest speed limiting value connection of each path point; replacing a curve part with a speed-down curve part in the speed-limit curve by using a line segment formed by connecting a speed-down starting endpoint and a speed-down stopping endpoint; replacing a curve part with a speed rising curve from a speed starting rising endpoint to a speed stopping rising endpoint in the speed limiting curve; and identifying the shape of the regulated speed limit curve, and dividing the speed limit curve into three speed limit modes, namely a constant speed mode, a step mode and a downhill mode based on the identified shape, wherein the constant speed mode represents a linear part with constant speed limit values, the step mode represents a part with jump from one constant speed limit value to another constant speed limit value, and the downhill mode represents a linear part with linear descent from one speed limit value to another speed limit value.
Optionally, if the speed limiting mode corresponding to each path point of the front path of the host vehicle is a constant speed mode in the future preset time period, the comprehensive planning of the acceleration and the speed of the host vehicle in the future preset time period includes: first uniform velocity mode: when the current speed of the vehicle is equal to a constant speed limit value and the current acceleration of the vehicle is equal to 0, planning that the speed of the vehicle at each moment in a preset time period in the future is the constant speed limit value, and planning that the acceleration of the vehicle at each moment in the preset time period in the future is 0; second constant speed mode: when the current speed of the vehicle is smaller than the constant speed limit value, or the current speed of the vehicle is equal to the constant speed limit value and the current acceleration of the vehicle is smaller than 0, controlling the vehicle to perform variable acceleration driving according to the uniform acceleration in a preset time period in the future; when the acceleration of the vehicle is increased to a preset maximum acceleration, controlling the vehicle to run at the preset maximum acceleration in a uniform acceleration manner until the speed of the vehicle reaches v const -v gap Whereinv const Represents the constant-speed limit value,v gap indicating a preset speedAn interval parameter; when the speed reachesv const -v gap Then, controlling the vehicle to follow the acceleration at each remaining moment of a preset time period in the futurea w =a max (v const -v w-1 )/v gap To perform variable acceleration running in whicha w Indicating the acceleration of the own vehicle at the current moment,a max representing the preset maximum acceleration of the vehicle,v w-1 indicating the speed of the vehicle at one moment; third constant speed mode: when the current speed of the vehicle is greater than the constant speed limit value, or the current speed of the vehicle is equal to the constant speed limit value and the current acceleration of the vehicle is greater than 0, controlling the vehicle to run at variable speed according to uniform reduction of the acceleration in a preset time period in the future; when the acceleration of the vehicle is reduced to a preset maximum deceleration, controlling the vehicle to run at uniform deceleration with the preset maximum deceleration until the speed of the vehicle reachesv const +v gap Whereinv const Represents the constant-speed limit value,v gap representing a preset speed interval parameter; when the speed reachesv const +v gap Then, controlling the vehicle to follow the acceleration at each remaining moment of a preset time period in the futurea w =a min (v w-1 -v const )/v gap Running at variable speed, in whicha w Indicating the acceleration of the own vehicle at the current moment,a min representing the preset maximum deceleration rate in question,v w-1 indicating the speed of the host vehicle at a time.
Optionally, if the speed limit mode corresponding to each path point of the front path of the host vehicle is a step mode in the future preset time period, the comprehensive planning of the acceleration and the speed of the host vehicle in the future preset time period includes: step path points with speed limit values changed in step are determined from the path points; before the step path point, carrying out constant speed mode planning on the acceleration and the speed of the vehicle in a future preset time period based on a constant speed limit value before the step; and after the step path point, carrying out constant speed mode planning on the acceleration and the speed of the vehicle in a future preset time period based on the constant speed limit value after the step.
Optionally, if the speed limit mode corresponding to each path point of the front path of the host vehicle is a downhill mode in the future preset time period, the comprehensive planning of the acceleration and the speed of the host vehicle in the future preset time period includes: determining a first speed limit end value and a second speed limit end value, wherein the first speed limit end value is a speed limit value corresponding to an end point of a speed limit curve for starting speed reduction, and the second speed limit end value is a speed limit value corresponding to an end point of the speed limit curve for stopping speed reduction; a high-speed threshold value and a low-speed threshold value are respectively taken between the first speed limiting end value and the second speed limiting end value and are used for representing the speed condition of the vehicle; calculating standard acceleration corresponding to the deceleration from the first speed limit end value to the second speed limit end value; if the vehicle is in a deceleration or uniform speed state at present, speed planning is carried out through a first downhill mode, a second downhill mode or a third downhill mode as follows; first downhill mode: when the current speed of the vehicle is greater than or equal to the first speed limit end value, calculating a first deceleration by the following formula
a start_const2 = max(a start_const2_raw ,a min )
a start_const2_raw = (v const2 +v 0 )(v const2 -v 0 )/(2s thb )
In the method, in the process of the invention,a start_const2 which represents the first deceleration rate in question,v const2 representing the second limit value of the speed limit,v 0 indicating the current speed of the host vehicle,s thb representing a distance value of the speed limit curve corresponding to the first speed limit end value to the second speed limit end value,a min representing the preset maximum deceleration rate in question,a start_const2_raw representing a first initial deceleration; respectively replacing preset maximum deceleration and constant speed limiting values in the third constant speed mode by using the first deceleration and the second speed limiting end value, and carrying out acceleration and acceleration of the vehicle in a future preset time period by using the third constant speed mode after parameter replacementPlanning the speed; a second downhill mode: when the current speed of the vehicle is greater than or equal to the low speed threshold value and less than the first speed limiting end value, calculating a second deceleration by the following formula
a suitable = max(a suitable_raw ,a min )
a suitable_raw =a const (v 0 -v low )/(v const1 -v low )
In the method, in the process of the invention,v 0 indicating the current speed of the host vehicle,v low representing the low-speed threshold value in question,v const1 representing the first limit value of the speed limit,a const which is indicative of the standard acceleration of the vehicle,a min representing the preset maximum deceleration rate in question,a suitable which represents the second deceleration rate in question,a suitable_raw representing a second initial deceleration; respectively replacing a preset maximum deceleration and a constant speed limit value in the third constant speed mode by using the second deceleration and the second speed limit value, and planning the acceleration and the speed of the vehicle in a future preset time period by using the third constant speed mode with the replaced parameters; third downhill mode: when the current speed of the vehicle is smaller than the low-speed threshold value, controlling the vehicle to accelerate and decelerate firstly; if the vehicle is in an accelerating state currently, speed planning is carried out through a fourth downhill mode or a fifth downhill mode as follows; fourth downhill mode: when the current speed of the vehicle is greater than or equal to the high-speed threshold value, planning the acceleration and the speed of the vehicle in a future preset time period through the second downhill mode; fifth downhill mode: and when the current speed of the vehicle is smaller than the high-speed threshold value, planning the acceleration and the speed of the vehicle in a future preset time period through the third downhill mode.
Optionally, if in the future preset time period, the speed limiting mode corresponding to each path point of the front path of the host vehicle is a constant speed mode, a downhill mode and a constant speed mode, the method further includes: estimating the distance travelled by the vehicle during decelerationd proper The method comprises the steps of carrying out a first treatment on the surface of the Calculating theoretical optimal deceleration positions proper_raw Whereins proper_raw =s th2 -d proper ，s th2 Representing the displacement of the second speed limit end value on the path; calculating an optimal start deceleration positions proper Whereins proper = min(s proper_raw ,s th1 )，s th1 Representing the displacement of the first speed limit end value on the path; when the vehicle is displaced s<s proper When the speed limiting method is used, the first speed limiting end value is used for replacing a constant speed limiting value in a constant speed mode, and the speed planning is carried out on the vehicle by adopting the constant speed mode; when the displacement s of the vehicle is more than or equal tos proper And when the vehicle is in a downhill mode, the speed planning is carried out on the vehicle.
According to a second aspect, an embodiment of the present invention provides a vehicle speed planning apparatus based on speed limit information, the apparatus including: the route point module is used for arranging a plurality of route points at equal intervals on a preset length section of a route in front of the host vehicle; the speed limit configuration module is used for reading the speed limit requirement information of the current path and giving an initial speed limit value to each path point based on the speed limit requirement information; the speed limit updating module is used for acquiring obstacle information in front of the vehicle, updating initial speed limit values of all the path points based on the obstacle information, and obtaining the latest speed limit values of all the path points; the speed limit curve module is used for generating a speed limit curve with speed limit values continuously changing along with the distance extension on the preset length road section through the latest speed limit values of all the path points; the speed planning module is used for comprehensively planning the acceleration and the speed of the vehicle in a preset time period in the future so as to change the speed of the vehicle in the preset time period in the future according to the speed limiting curve; and the planning period jumping module is used for returning to the step of arranging a plurality of path points on the preset length section of the front path of the vehicle at equal intervals after the current speed planning period is passed, and entering the next speed planning period.
According to a third aspect, an embodiment of the present invention provides a domain controller, comprising: the system comprises a perception processing unit, a decision processing unit, a control processing unit and a communication unit, wherein the perception processing unit, the decision processing unit, the control processing unit and the communication unit are in communication connection, computer instructions are stored in the decision processing unit, and the decision processing unit executes the computer instructions so as to execute the method of the first aspect or any optional implementation manner of the first aspect.
According to a fourth aspect, embodiments of the present invention provide a computer readable storage medium storing computer instructions for causing a computer to perform the method of the first aspect, or any one of the alternative embodiments of the first aspect.
The technical scheme that this application provided has following advantage:
according to the technical scheme, when each speed planning period starts, a plurality of path points are arranged on a preset length section of a front path of the vehicle at equal intervals; then, giving an initial speed limit value to each path point based on the speed limit requirement information of the path; then updating the initial speed limit value of each path point based on the obstacle information in front of the vehicle to obtain the latest speed limit value of each path point; then drawing and generating a speed limit curve with speed limit values continuously changing along with the distance extension on a road section with a preset length through the latest speed limit values of all the path points; finally, comprehensively planning the acceleration and the speed of the vehicle in a preset time period based on a speed limit curve so as to enable the speed of the vehicle to be close to the speed limit curve; after the preset time period, the cycle planning is finished, the first step is returned to set a plurality of route points on the road section with the preset length in front of the vehicle again, and the next speed planning cycle is entered. Through the steps, the overall speed of the vehicle is closely close to the speed limiting curve, and the speed limiting curve has the effect of stable change at each point of the path, so that the vehicle can run at the maximum speed, the situation of instantaneous abrupt increase and abrupt decrease of the speed of the vehicle can be hardly caused, and the comfort level of drivers and passengers can be remarkably improved.
Drawings
The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and should not be construed as limiting the invention in any way, in which:
FIG. 1 shows a prior art speed limit graph;
FIG. 2 is a schematic diagram showing steps of a vehicle speed planning method based on speed limit information according to an embodiment of the present invention;
FIG. 3 illustrates a schematic of a speed limit curve generated in one embodiment of the invention;
FIG. 4 illustrates another speed limit graph generated in one embodiment of the invention;
FIG. 5 shows a schematic diagram of a step mode of a speed limiting curve in one embodiment of the invention;
FIG. 6 illustrates a schematic of a downhill mode of a speed limit curve in one embodiment of the invention;
FIG. 7 shows a schematic of a trapezoidal pattern of speed limit curves in one embodiment of the invention;
FIG. 8 is a schematic diagram showing a vehicle speed planning apparatus based on speed limit information according to an embodiment of the present invention;
fig. 9 is a schematic diagram showing the structure of a domain controller according to an embodiment of the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, based on the embodiments of the invention, which a person skilled in the art would obtain without making any inventive effort, are within the scope of the invention.
With the development of automatic driving technology, various speed planning algorithms exist in the market at present, and most algorithms achieve the aim of keeping the vehicle running at a high speed as much as possible on a full path, so that the vehicle can respond to control signals of acceleration and deceleration in time and reach a terminal point at the fastest speed under the conditions of not exceeding a road section speed limit value and not generating collision. However, the current speed planning technology is too dead, and a speed limit value is usually set for each road section with a longer distance, for example, as shown in fig. 1, the speed planning method causes the situation that the speed of the vehicle is too fast in a short time, and the speed is particularly obvious in a decelerating scene, so that the comfort of drivers is seriously affected.
Referring to fig. 2, in one embodiment, a vehicle speed planning method based on speed limit information specifically includes the following steps:
step S101: a plurality of route points are arranged on a preset length section of a route in front of the host vehicle at equal intervals.
Specifically, in the embodiment of the invention, the route points of the road section with the preset length in front of the vehicle are divided, and speed limit information is given to each route point. It should be noted that, the setting of the interval between each path point and the path point in this embodiment is used to ensure that the number of path points cannot be too small and the path points are distributed uniformly, ensure the accuracy of speed limit information of the whole path, reduce the calculation difficulty of the subsequent speed planning, and improve the accuracy of the speed planning. Specifically, too small of the interval setting of the path points can cause too many path points, too large of calculation amount, difficult support of the current chip equipment, too large of the interval setting of the path points can cause too small of the number of the path points, and the calculation result of the follow-up speed planning is not accurate enough. In this embodiment, a path point is set at a distance of 1 meter, and in general, the distance between the path points may be selected to be between 0.5 meters and 10 meters, but with the development of the chip technology in the future, the distance between the path points may also be smaller after the calculation force is improved, which is not limited in particular in this embodiment. In the embodiment of the invention, the preset length road section is selected 100 meters each time, the calculation level of the current chip technology is considered, the path point of the path with the length of 100 meters in front of the vehicle is selected to divide the path point and generate the speed limiting information, the effect of generating the speed limiting information is optimal, the preset length road section can also adopt shorter or longer values along with the development of the future chip technology, and the embodiment is not limited in particular.
Step S102: and reading the speed limit requirement information of the current path, and assigning an initial speed limit value to each path point based on the speed limit requirement information.
Specifically, this step is used to read the speed limit requirement information of the route from the road management system of the campus, the urban traffic, etc., so as to assign an initial speed limit value to each route point. For example: in a certain closed industrial park, speed limit requirement information is pre-configured on one section of path, the speed limit requirement information records that the speed limit value of 0-200 m of the current path is 8.5m/s, the speed limit value of 200-250 m is 4.3m/s, the speed limit value of 250-500 m is 10m/s, and the like. And marking an initial speed limit value for each path point in advance, wherein the speed limit value of the current path point represents the speed limit condition of a road section at an interval between the current path point and the last path point.
Step S103: and acquiring the obstacle information in front of the vehicle, and updating the initial speed limit value of each path point based on the obstacle information to obtain the latest speed limit value of each path point.
Specifically, the speed limit value given to each path point in step S102 does not consider the obstacle near the path, and when there is an obstacle on the path, it is also necessary to calculate the actual speed of the vehicle in real time according to the position of the obstacle, so as to avoid the collision between the vehicle and the obstacle. In this embodiment, the obstacle recognition system recognizes the obstacle information on the path, and the technical means of performing obstacle recognition by using the camera, the radar, and other devices may refer to the prior art, which is not described in detail in the present invention. Then, the embodiment calculates the maximum allowable speed of the vehicle passing through each path point based on the obstacle information in front of the vehicle, so as to update the initial speed limit value of each path point and obtain the latest speed limit value of each path point.
Step S104: and generating a speed limit curve with speed limit values continuously changing along with the distance extension on a road section with a preset length through the latest speed limit values of all the path points.
Step S105: and comprehensively planning the acceleration and the speed of the vehicle in a preset time period in the future so as to change the speed of the vehicle according to a speed limit curve in the preset time period in the future.
Step S106: after the current speed planning period, returning to the step of setting a plurality of path points on the preset length section of the front path of the vehicle at equal intervals, and entering the next speed planning period.
Specifically, in this embodiment, curve fitting is performed through the latest speed limit values of each path point, so that a speed limit curve with speed limit values continuously changing along with the distance extension on a preset length road section can be generated, the horizontal axis of the curve is the distance extension on the preset length road section, and the latest speed limit value is the vertical axis. Taking fig. 3 as an example, the speed limit curve generated by the embodiment of the invention changes along with the change of the path point, and the actual speed limit information of each position on the path is more accurate by reasonably selecting the path point. Compared with the conventional speed limiting curve in fig. 1, the speed limiting method can guide the vehicle to flexibly adjust the acceleration and the speed of the vehicle according to the speed limiting value of each path point, so that the actual running speed of the vehicle is controlled to change according to the change rule of the speed limiting curve, and when the actual running speed of the vehicle is most matched with the speed limiting curve, the vehicle can be ensured to hardly generate excessive shake under the premise of fastest running, and the comfort level of drivers and passengers can be obviously improved.
Specifically, in order to ensure accuracy of the speed planning, the preset time period and the speed planning period should be selected as small as possible, and in this embodiment, each speed planning period is set to 0.1s, and the preset time period is 7 seconds in length. In order to avoid wasting computational resources, a future 7-second speed is planned each time, wherein 0.1s is taken as one time, and the future 7-second speed is divided into 70 times for speed planning. For example, in the current speed planning period, firstly, 100 path points are defined at 1 meter intervals in front of the vehicle, a speed limit value is generated for each path point, then, the actual speed value of the vehicle for 7 seconds in the future is calculated based on the speed limit values generated by the 100 path points, after 0.1 second passes, the current planning period is ended, 100 path points need to be redetermined, the actual speed of the vehicle for 7 seconds in the future is further recalculated, and because the speed planning period time is shorter, the redetermined path points and the speed of the 7 seconds in the future in each planning period are finely tuned on the basis of the previous planning period.
Specifically, in one embodiment, the step S103 specifically includes the following steps:
step one: when the obstacle information indicates that the vehicle has a static obstacle in front of the vehicle, calculating the latest speed limit value corresponding to each path point capable of stopping the vehicle at the first preset distance position in front of the static obstacle.
Specifically, the embodiment of the invention analyzes the speed limit condition of each path point from four aspects of a static obstacle, a walking obstacle, a reverse obstacle and a vehicle following obstacle, thereby ensuring the updating accuracy of the latest speed limit value of each path point. In this embodiment, a first preset distance is defined for the static obstacle, and when the vehicle finds the static obstacle, the latest speed limit value of each path point is generated to guide the vehicle to stop at a position just in front of the static obstacle by the first preset distance, so that the vehicle can be smoothly decelerated to the greatest extent according to a speed limit curve, and the comfort level of drivers and passengers is improved.
Specifically, in the embodiment of the invention, for the path points within a first preset distance (for example, 15 meters) in front of the static obstacle, the latest speed limit value is updated to be 0m/s; for each path point exceeding the first preset distance in front of the static obstacle, updating the latest speed limit value of each path point according to the following formula
Figure SMS_7
Figure SMS_8
In the method, in the process of the invention,
Figure SMS_9
indicating the maximum deceleration of the vehicle during normal running (e.g. -0.8m/s 2 ) Variable->
Figure SMS_10
Path point to static obstacle representing current updated speed limitDistance of the object.
In addition, the latest speed limit value for the route points behind the static obstacle is updated to 0m/s all the time.
Step two: when the obstacle information indicates that the front of the vehicle has a passing obstacle passing through the path of the vehicle, estimating the passing collision point of the vehicle and the passing obstacle, and calculating the latest speed limit value of each path point in front of the vehicle by taking the passing collision point as a static obstacle.
Step three: when the obstacle information indicates that the front of the vehicle has a reverse obstacle, estimating a reverse collision point of the vehicle and the reverse obstacle, and calculating the latest speed limit value of each path point in front of the vehicle by taking the reverse collision point as a static obstacle.
Specifically, in this embodiment, estimating the traveling collision point of the host vehicle and the traveling obstacle may be achieved by predicting the trajectory of the traveling obstacle, and first predicting the trajectory of the traveling obstacle (the trajectory of the traveling obstacle is predicted as in the prior art, and is not described in detail in this embodiment), so as to determine the intersection point of the trajectory of the traveling obstacle and the path of the host vehicle, and by analyzing whether the host vehicle and the traveling obstacle reach the intersection point at the same time, the estimation of the traveling collision point may be completed. In addition, the reverse collision point of the host vehicle and the reverse obstacle is estimated, and the present embodiment estimates the collision position by assuming that both the host vehicle and the reverse obstacle travel at a constant speed at the current speed. And then, regarding the retrograde collision point and the traversing collision point as static barriers, and generating the latest speed limit value of each path point by adopting the flow of the step one.
Step four: when the obstacle information indicates that the front of the vehicle has a following obstacle requiring following, determining a minimum following distance and a maximum following distance.
Specifically, when the obstacle in front of the host vehicle includes a following obstacle, the present embodiment first determines a minimum following distance and a maximum following distance, and then generates speed limit information of each path point according to the minimum following distance and the maximum following distance, so as to guide the host vehicle to be able to stably maintain between the minimum following distance and the maximum following distance, so as to facilitate subsequent planning of a vehicle speed with higher stability, where the minimum following distance and the maximum following distance may be determined through expert experience. Specifically, in the present embodiment, in order to further improve the stability of the vehicle speed of the subsequent plan, the minimum following distance and the maximum following distance are adjusted in real time by the speed of the following obstacle (e.g., the vehicle traveling ahead).
Specifically, assume that the speed of the following obstacle at this time isv obstacle The following speed of the vehicle is then increasedv follow Preset to be equal tov obstacle . During the following process, if the speed change of the following obstacle is less than 2m/s, the following obstacle is not updatedv follow To prevent frequent changes in the following speed from causing the vehicle to constantly switch between acceleration and deceleration. The present embodiment adopts the minimum following distance of 5 seconds following speed d follow_min The distance travelled with the speed of 10 seconds is the maximum following distanced follow_max I.e.
d follow_min = 5v follow
d follow_max = 10v follow
Step five: when the distance between the vehicle and the obstacle is between the minimum following distance and the maximum following distance, calculating the latest speed limit value of each path point in front of the vehicle by the following method
Figure SMS_11
Figure SMS_12
In the method, in the process of the invention,
Figure SMS_13
is the maximum deceleration of the vehicle during normal driving, < >>
Figure SMS_14
Distance from the route point to the obstacle following the car for which the current participation calculates the latest speed limit value, +.>
Figure SMS_15
Equal to the travel speed of the following obstacle.
Specifically, assume that the vehicle is traveling at the current path point with acceleration
Figure SMS_16
And (3) performing uniform deceleration movement and stopping at the position of the front vehicle-following obstacle, and obtaining the speed of the vehicle at different path points according to the assumption, thereby limiting the speed. Based on the above assumption, the speed of the vehicle at different waypoints is calculated according to the following principle: if the vehicle is in order tov 1 At an initial speed ofaMake uniform acceleration movement for acceleration until the speed becomesv 2 Assume that the vehicle is traveling a distance at this timesThe following relationship is satisfied:
v 2 2 -v 1 2 = 2as
in the case of the above-mentioned type of device,v 1 =
Figure SMS_17
，v 2 =0m/s，a=a min ，s=d i thus, it is
Figure SMS_18
。
In the speed limiting mode, when the position of the vehicle is between the minimum following distance and the maximum following distance, the latest speed limiting value of each path point in front of the vehicle takes the following speed v follow And
Figure SMS_19
is a smaller value of (a). Therefore, the speed of the vehicle can be limited to approach to the speed of the front following obstacle, and the distance between the two vehicles can be stably kept.
Step six: when the distance between the vehicle and the obstacle is smaller than the minimum following distance, calculating the latest speed limit value of each path point in front of the vehicle according to the following formula
Figure SMS_20
In the method, in the process of the invention,c times is a preset scaling parameter greater than 1.
Specifically, when the distance between the host vehicle and the vehicle following obstacle is smaller than the minimum following distance, the host vehicle and the vehicle following obstacle are indicated to be very close, so that the vehicle following safety is ensured. Thereby the conventional following speed is adjusted by presetting the zoom parameter
Figure SMS_21
Performing reduction, the embodiment selectsc times 1.2./>
Figure SMS_22
The speed of the vehicle from the position of the route point to the position of the obstacle can be stopped, so the vehicle is not changed. In the speed limiting mode, the speed of the vehicle passing through each path point is smaller than the speed of the front vehicle following obstacle, so that the distance between the vehicle and the vehicle following obstacle is controlled to be gradually increased. When the distance is increased tod follow_middle = (d follow_min +d follow_max ) And (2) continuously calculating the latest speed limit value of each path point in a mode of the step five for accelerating the vehicle to the speed of the front vehicle following obstacle.
Step seven: when the distance between the vehicle and the obstacle is greater than the maximum following distance, calculating the latest speed limit value of each path point in front of the vehicle by adopting the following formula
Figure SMS_23
In the method, in the process of the invention,
Figure SMS_24
indicating the maximum following distance.
Specifically, when the distance between the vehicle and the obstacle following the vehicle is greater than the maximum following distance, the distance between the vehicle and the obstacle following the vehicle is too far, and the vehicle can be accelerated properly on the premise of safety following the vehicle. Specifically includes two cases when
Figure SMS_25
When the current path point participating in calculating the latest speed limit value is within the maximum following distance, the current path point passesc times Speed of opposite vehicle
Figure SMS_26
After a small expansion, the latest speed limit value of the route point is selected +.>
Figure SMS_27
The speed of the vehicle can be limited to be slightly larger than that of the front vehicle, and the aim of controlling the distance between the vehicle and the obstacle following the vehicle to be reduced slowly is fulfilled. When->
Figure SMS_28
When the path point representing the current calculated latest speed limit value is out of the maximum following distance, the vehicle can accelerate faster without considering the problem of speed overshoot, thereby setting the latest speed limit value of each path point to be higher +.>
Figure SMS_29
. At->
Figure SMS_30
The larger speed limit value is set in the distance range, so that the speed of the vehicle can exceed the speed of the front vehicle, and the distance between the vehicle and the vehicle following obstacle is guided to be accelerated and reduced.
Specifically, in an embodiment, the second step specifically includes the following steps:
step eight: and estimating each arrival time when the vehicle arrives at any position in front at the current speed at a constant speed.
Step nine: based on the running track of the passing obstacle, one by one testing whether the vehicle collides with the passing obstacle at a certain position in front from the current position of the vehicle, and taking the first collision position obtained by testing as a passing collision point. Wherein the steps of each test include:
1. extracting target arrival time of the vehicle reaching the current test position from each arrival time;
2. if the passing obstacle passes the current test position in a preset second before and after the target reaching moment, taking the current test position as a collision position;
3. and if the distance between the crossing barrier and the current test position at the target arrival time is within a second preset distance, taking the current test position as the collision position.
Specifically, considering that in a practical application scenario, a vehicle has a certain collision volume, if the vehicle is regarded as only one particle, the estimated passing collision position is not accurate enough. Based on the above, in order to improve the safety, the embodiment of the invention adopts a relatively conservative strategy to judge whether the collision occurs. Firstly, estimating that the vehicle runs at a constant speed at the current speed and reaches any position in frontp i Each arrival time of (a)t i For example, each time a vehicle passes 1 meter, the vehicle is estimated to reach the front every 1 meter t i . Then, it is tested whether the obstacle is in positiont i When the preset seconds pass the current test position, such as the 10 th test, then the obstacle is tested to determine whether the obstacle is at the target arrival timet 10 Passes the current test position 3 seconds before and after. If the test passes, it is considered that the enclosure of the obstacle passing through collides with the enclosure of the host vehicle, and the position is regarded as a collision position. In addition, if the obstacle is traversed at the target arrival timet 10 If the distance from the current test position is within a second preset distance (for example, 15 meters), the obstacle is considered to be very close to the vehicle, so that the collision of the vehicle shell occurs, and the current test position is taken as the collision position. By the estimation method of the embodiment, the safety and reliability of the following vehicle speed planning result can be further improved on the premise of fully considering the external volume of the vehicle.
Specifically, in an embodiment, the step S104 specifically includes the following steps:
step ten: and generating a speed limit curve based on the connection of the latest speed limit values of all the path points by taking the extending distance of the road section with the preset length as a horizontal axis and the latest speed limit value as a vertical axis.
Step eleven: and replacing the curve part of the speed limit curve, in which the speed is reduced, by using a line segment formed by connecting a speed start reduction endpoint and a speed stop reduction endpoint.
Step twelve: and replacing the curve part of the speed limit curve from the speed start rising end point to the speed stop rising end point by using a step curve of the speed start rising end point.
Step thirteen: and identifying the shape of the regulated speed limiting curve, and dividing the speed limiting curve into three speed limiting modes, namely a constant speed mode, a step mode and a downhill mode based on the identified shape, wherein the constant speed mode represents a linear part with constant speed limiting values, the step mode represents a part with jump from one constant speed limiting value to another constant speed limiting value, and the downhill mode represents a linear part with linear drop from one speed limiting value to another speed limiting value.
Specifically, the speed limit curve shown in fig. 3 is drawn first according to the latest speed limit value of each path point. Then, for a curve portion in which the speed is reduced in the speed limit curve, which includes one speed start reduction end point and one speed stop reduction end point, the present embodiment connects straight lines through the two end points, and replaces the curve at the corresponding position with the obtained line segment. Through the adjustment of the step, the speed-decreasing part represents the trend of speed-limiting information decreasing at a constant speed by a straight line, and the tiny speed fluctuation in the speed-limiting curve is eliminated, so that the influence on the vehicle to keep running at the maximum allowable speed is negligible, but the calculation complexity can be obviously reduced, and the speed planning efficiency is improved. Similarly, if the speed limit is gradually increased, a speed limit point needs to be added besides the head end and the tail end, so that a step curve is generated to replace the gradually-rising speed limit curve. The step part can be regarded as the splicing of two constant speed limiting sections, so that the calculation difficulty of the subsequent speed planning is reduced. By the processing of the step eleven and the step twelve, the shape of the speed limit curve similar to that shown in fig. 4 is obtained and used for representing the speed limit value of each position 100 meters in front of the vehicle. And finally, recognizing the shape of the regulated speed limit curve, and dividing the speed limit curve into three speed limit modes, namely a constant speed mode (a section of horizontal straight line consisting of the latest speed limit values, and no change of the latest speed limit values in a period of time), a step mode (step straight line) and a downhill mode (straight line obliquely downwards) based on the recognized shape. According to the embodiment, the speed planning is independently carried out for each mode, so that the calculation difficulty of the overall speed planning can be remarkably reduced.
Specifically, in an embodiment, for the constant speed mode, in step S105, the speed planning is performed in the following three constant speed modes.
First uniform velocity mode: when the current speed of the vehicle is equal to the constant speed limit value and the current acceleration of the vehicle is equal to 0, planning that the speed of the vehicle at each moment in a preset time period in the future is the constant speed limit value, and planning that the acceleration of the vehicle at each moment in the preset time period in the future is 0.
Specifically, the constant speed limit value is a speed limit value in a constant speed mode, and in this period, the latest speed limit value corresponding to each path point is unchanged, and the speed limit curve is a horizontal straight line. If the vehicle is currently in a speed constant form of a constant speed limiting value, the current speed is kept, and the vehicle is guaranteed to run at the highest speed. Therefore, the acceleration of the vehicle at each moment in a preset time period (for example, 7 seconds) in the future is planned to be 0, and the speed change is not carried out.
Second constant speed mode: when the current speed of the vehicle is smaller than the constant speed limit value, or the current speed of the vehicle is equal to the constant speed limit value and the current acceleration of the vehicle is smaller than 0, controlling the vehicle to perform variable acceleration driving according to the uniform acceleration in a preset time period in the future; when the acceleration of the vehicle is increased to the preset maximum acceleration, the vehicle is controlled to uniformly accelerate with the preset maximum acceleration until the speed of the vehicle reaches v const -v gap Whereinv const Represents a constant-speed limiting value,v gap representing a preset speed interval parameter; when the speed reachesv const -v gap Then, controlling the vehicle to follow the acceleration at each remaining moment of a preset time period in the futurea w =a max (v const -v w-1 )/v gap To perform variable acceleration running in whicha w Indicating the acceleration of the own vehicle at the current moment,a max indicating that the preset maximum acceleration is to be reached,v w-1 indicating the speed at a moment on the vehicle,windicating the current time.
Specifically, if the vehicle speed of the vehicle does not reach the constant speed limit value, or the vehicle speed of the vehicle reaches the constant speed limit value, the acceleration of the vehicle is negative and is in a deceleration state. In order to ensure that the vehicle can run against the constant speed limiting value, the acceleration of the vehicle needs to be increased, so that the vehicle enters an acceleration state. It should be noted that if the acceleration of the host vehicle is set too large, the host vehicle still is in an acceleration state when reaching a constant speed limiting value, so that the speed is overshooting, the host vehicle is automatically decelerated after overshooting, and the phenomenon that the acceleration and the speed are frequently fluctuated occurs, so that a driver and passengers feel uncomfortable. Based on this, the present embodiment first employs jerk along the 100 meter pathj max Gradually increasing the acceleration to a preset maximum acceleration a max This moment is recorded ast jerk In a time of 0 tot jerk The vehicle is in a state of variable acceleration running. Then make the host vehicle toa max Evenly accelerate tov const -v gap This moment is recorded ast acc 。v gap Can be set according to expert experience, e.gv gap= 0.1v const I.e. controlling the time of the vehiclet jerk ~t acc According to a preset maximum accelerationa max Evenly accelerating to a constant speed limit valuev const Is a part of the area around (a). At the moment of timet acc Then the acceleration is gradually reduced time by time to obtain the accelerationa w =a max (v const -v w-1 )/v gap Gradually accelerating to a constant speed limit valuev const (whereinw=1, 2, …,70, representing 70 for 7 seconds in the future, 0.1s at each moment); wherein, the method comprises the following steps ofv const -v w-1 )/v gap The advantage of this strategy is that when the vehicle speed approaches a constant speed limit, the control acceleration gradually scales down by changing the accelerationThe state is slowly accelerated to a constant speed limiting value, so that the speed overshoot is avoided, the phenomenon that the acceleration and the speed are frequently fluctuated is obviously reduced, and the comfort level of drivers and passengers is improved.
The motion model of the second uniform mode is represented as follows:
in the period of time (0,t jerk ]the motion model adopted is
Figure SMS_31
In the jerk ofj=j max Time interval deltatThe time of the first time period is =0.1 seconds,
Figure SMS_32
indicating the displacement of the current moment of the vehicle,
Figure SMS_33
indicating the acceleration at the next moment, +.>
Figure SMS_34
Indicating the next time speed +.>
Figure SMS_35
Indicating the current time speed, +. >
Figure SMS_36
Indicating the displacement of the vehicle for driving at the next moment.
In a time period of%t jerk ,t acc ]The motion model adopted is
Figure SMS_37
In the acceleration at the current timea w =a max The other symbols are as above.
In a time period of%t acc ,t max ]The motion model adopted is
Figure SMS_38
In the jerk ofj=j max Acceleration ofa=a max The other symbols are as above.
Third constant speed mode: when the current speed of the vehicle is greater than the constant speed limit value, or the current speed of the vehicle is equal to the constant speed limit value and the current acceleration of the vehicle is greater than 0, controlling the vehicle to run at variable speed according to uniform reduction of the acceleration in a preset time period in the future; when the acceleration of the vehicle is reduced to the preset maximum deceleration, the vehicle is controlled to run at uniform deceleration at the preset maximum deceleration until the speed of the vehicle reachesv const +v gap Whereinv const Represents a constant-speed limiting value,v gap representing a preset speed interval parameter; when the speed reachesv const +v gap Then, controlling the vehicle to follow the acceleration at each remaining moment of a preset time period in the futurea w =a min (v w-1 -v const )/v gap Running at variable speed, in whicha w Indicating the acceleration of the own vehicle at the current moment,a min indicating a preset maximum deceleration rate that is to be set,v w-1 indicating the speed of the host vehicle at a time.
Specifically, the third constant speed mode is similar to the second constant speed mode, if the current speed of the host vehicle is greater than the constant speed limit value, or the current speed of the host vehicle is equal to the constant speed limit value but the current acceleration of the host vehicle is greater than 0 (in an acceleration state), which indicates that the host vehicle has overspeed or is about to overspeed, so that deceleration is required. The present embodiment employs deceleration in the direction of the waypoint j min Planning that the acceleration of the vehicle gradually decreases to a preset maximum decelerationa min (negative value), noted at this point ast jerk . Then bya min Uniformly decelerating tov const +v gap This moment is recorded ast acc . At the moment of timet acc Thereafter, the vehicle is controlled to acceleratea w =a min (v w-1 -v const )/v gap Gradually slow down tov const The method comprises the steps of carrying out a first treatment on the surface of the The third constant speed mode has the advantages that when the speed of the vehicle approaches to the constant speed limit value, the absolute value of the acceleration is gradually reduced, so that the speed overshoot is avoided, the phenomenon that the acceleration and the speed are frequently fluctuated is reduced, and the comfort level of drivers and passengers is improved. Wherein can be taken outj min =-0.2m/s 3 ，a min =-0.8m/s 2 This is by way of example only, and not by way of limitation.
Specifically, in one embodiment, for the step mode, the step S105 specifically includes the following steps:
step fourteen: and determining a step path point with the speed limit value subjected to step change from the path points.
Fifteen steps: and before the step path point, carrying out constant speed mode planning on the acceleration and the speed of the vehicle in a future preset time period based on the constant speed limiting value before the step.
Step sixteen: and after the step path point, carrying out constant speed mode planning on the acceleration and the speed of the vehicle in a future preset time period based on the constant speed limiting value after the step.
Specifically, as shown in fig. 5, a step point at which the constant speed limit value is stepped is found, and the position corresponding to the step point is expressed as s tha . In the displacement interval of [0 ],s tha ) At a constant speed limit before stepv const1 Performing speed planning for the speed limitation by adopting the strategy of the uniform speed mode; in the displacement interval [s tha ,100]With constant speed limit after stepv const2 And (5) carrying out speed planning by adopting a strategy of a uniform speed mode for speed limiting. Therefore, the vehicle keeps running at the maximum speed, and meanwhile, the stable change of the speed and the acceleration of the vehicle is maintained, so that the comfort level of drivers and passengers is remarkably improved.
Specifically, in one embodiment, for the downhill mode, the step S105 specifically includes the following steps:
seventeenth step: determining a first speed limit end value and a second speed limit end value, wherein the first speed limit end value is a speed limit value corresponding to an end point of a speed limit curve for starting speed reduction, and the second speed limit end value is a speed limit value corresponding to an end point of the speed limit curve for stopping speed reduction; respectively taking a high-speed threshold value and a low-speed threshold value between the first speed limiting end value and the second speed limiting end value, and representing the speed of the vehicle; and calculating the standard acceleration corresponding to the deceleration from the first speed limit end value to the second speed limit end value.
Specifically, as shown in fig. 6, in order to improve the comfort of the driver and the passengers, it is ensured that the vehicle stably runs in a downhill mode in which the speed limit value is uniformly reduced. The first speed limiting end value, the second speed limiting end value, the high speed threshold value, the low speed threshold value and the standard acceleration are determined in advance and used for subsequent calculation.
v diff =v const1 -v const2
v high =v const2 + 0.9v diff
v low =v const2 + 0.6v diff
a const = (v const2 +v const1 )(v const2 -v const1 )/(2s thb )
Wherein, the liquid crystal display device comprises a liquid crystal display device,v const1 is a first speed limit threshold value, and the first speed limit value,v const2 is a second speed limit threshold value, and the speed limit value is a second speed limit threshold value,v high indicating a high-speed threshold value of the high-speed signal,v low representing a low-speed threshold value,a const the standard acceleration is expressed, the standard acceleration is expressed as the acceleration that the vehicle can exactly decelerate from the first speed limit end value to the second speed limit end value when driving from the position of the first speed limit end value to the position of the second speed limit end value,s thb representing a distance value of the speed limit curve corresponding to the first speed limit end value to the second speed limit end value,v diff representing a speed limit difference between the first speed limit value and the second speed limit value.
Eighteenth step: and if the vehicle is in a deceleration or uniform speed state currently, performing speed planning through a first downhill mode, a second downhill mode or a third downhill mode as follows.
First downhill mode: when the current speed of the vehicle is greater than or equal to the first speed limiting end value, calculating a first deceleration by the following formula
a start_const2 = max(a start_const2_raw ,a min )
a start_const2_raw = (v const2 +v 0 )(v const2 -v 0 )/(2s thb )
In the method, in the process of the invention,a start_const2 the first deceleration rate is indicated and the first deceleration rate,v const2 representing a second limit-speed limit value, the second limit-speed limit value,v 0 indicating the current speed of the host vehicle,s thb representing a distance value of the speed limit curve corresponding to the first speed limit end value to the second speed limit end value,a min indicating a preset maximum deceleration rate that is to be set,a start_const2_raw representing a first initial deceleration.
And respectively replacing preset maximum deceleration and constant speed limiting values in a third constant speed mode by using the first deceleration and the second speed limiting end value, and planning the acceleration and the speed of the vehicle in a future preset time period by using the third constant speed mode after parameter replacement.
Specifically, if the host vehicle is currently in a deceleration or constant speed state, but the current speed of the host vehicle is greater than or equal to the first speed limit end valuev const1 When the vehicle is overspeed, the vehicle needs to be decelerated with a large absolute value and then passes througha start_const2_raw = (v const2 +v 0 )(v const2 -v 0 )/(2s thb ) Calculating a first initial decelerationa start_const2_raw (sign negative) since the calculated first initial deceleration may be smaller than the preset maximum decelerationa min (the sign is negative), the larger value of the first initial deceleration and the maximum deceleration is taken as the first deceleration. Then, the preset maximum deceleration and the constant speed limiting value in the third constant speed mode are replaced by the first deceleration and the second speed limiting value respectively, and the speed planning problem of the first downhill mode is converted into the first speedAnd planning the acceleration and the speed of the vehicle in a future preset time period through the third constant speed mode after parameter replacement. Therefore, the global speed of the vehicle can gradually slow down close to the speed limiting curve of the downhill, and finally is reduced to a second speed limiting end value. And the planning logic for calling the uniform speed mode is simple, the calculation difficulty is low, the speed planning efficiency can be improved, and the comfort of drivers and passengers is ensured.
A second downhill mode: when the current speed of the vehicle is greater than or equal to the low speed threshold value and less than the first speed limiting end value, calculating the second deceleration by the following formula
a suitable = max(a suitable_raw ,a min )
a suitable_raw =a const (v 0 -v low )/(v const1 -v low )
In the method, in the process of the invention,v 0 indicating the current speed of the host vehicle,v low representing a low-speed threshold value,v const1 indicating a first limit value of the speed limit,a const the standard acceleration is indicated as such,a min indicating a preset maximum deceleration rate that is to be set,a suitable a second deceleration rate is indicated and a second deceleration rate,a suitable_raw representing a second initial deceleration;
and respectively replacing preset maximum deceleration and constant speed limiting values in a third constant speed mode by using the second deceleration and the second speed limiting end value, and planning the acceleration and the speed of the vehicle in a future preset time period by using the third constant speed mode after parameter replacement.
Specifically, if the host vehicle is currently in a deceleration or uniform speed state, and at the same time, the current speed of the host vehicle is greater than or equal to a low speed threshold valuev low And is smaller than the first speed limit end valuev const1 The current speed of the vehicle is proper, and the vehicle can be decelerated through a moderate deceleration. Thus, the embodiment of the invention passes througha suitable_raw =a const (v 0 -v low )/(v const1 -v low ) Calculating a second initial deceleration due to the calculated second initial decelerationa suitable_raw Possibly less than a preset maximum decelerationa min The larger value of the second initial deceleration and the maximum deceleration is thus taken as the second deceleration. And similarly, respectively replacing a preset maximum deceleration and a constant speed limiting value in a third constant speed mode by using the second deceleration and the second speed limiting end value, converting the speed planning problem of the second downhill mode into the problem of the third constant speed mode, and planning the acceleration and the speed of the vehicle in a future preset time period through the third constant speed mode after parameter replacement. Therefore, the global speed of the vehicle can gradually slow down close to the speed limiting curve of the downhill, and finally is reduced to a second speed limiting end value. And the planning logic for calling the uniform speed mode is simple, the calculation difficulty is low, the speed planning efficiency can be improved, and the comfort of drivers and passengers is ensured.
Third downhill mode: and when the current speed of the vehicle is smaller than the low-speed threshold value, controlling the vehicle to accelerate and decelerate.
Specifically, in this embodiment, if the host vehicle is currently in a deceleration or uniform speed state, and meanwhile, the current speed of the host vehicle is smaller than the low speed threshold, it is indicated that the current speed of the host vehicle is too slow, and the host vehicle should accelerate and decelerate first. For this purpose, the present embodiment first determines the start deceleration at the start of decelerationa expect So as to better plan the time point to which the vehicle should accelerate to start decelerating, on one hand, in order to ensure that the full-path running speed of the vehicle is as high as possible, on the other hand, the speed and the acceleration change times of the vehicle are ensured to be minimum, and the driving comfort level is improved. It should be noted that the start-up decelerationa expect Should be slightly smaller than the standard decelerationa const Therefore, the vehicle can be close to the speed limit curve and cannot exceed the speed limit curve when accelerating, and the embodiment takes the initial starting decelerationa expect_raw =0.75a const 。
Due to initial start-up decelerationa expect_raw Possibly less than a preset maximum decelerationa min So start deceleration takes initial valueThe larger of the start deceleration and the maximum deceleration.
a expect = max(a expect_raw ,a min )
Then, a specific flow of speed planning is started:
1. increasing from 0 seconds over timet max (e.g., 7 seconds), and calculating the velocity information corresponding to every 0.1 seconds later. As before, at 0 th second the acceleration is a 0 Time of daytAcceleration of (2) isa t,raw =a 0 +j max t，j max Indicating jerk. Due to the fact that the acceleration cannot exceed the maximum accelerationa max Thus taking the timetAcceleration of (2) isa t =min(a t,raw ,a max ). From another point of view, it can be determined that the jerk is active for a period of time oft jerk =(a max -a 0 )/j max : i.e. whent≤t jerk At the time of jerk ofj max ；t>t jerk At a jerk of 0m/s 3 。
2. During step 1 acceleration, each time is estimated from time 0 at the same timet k How long it takes to reduce the speed to the second limitv const2 Displacement of the vehicles estimate . The estimation method is as follows: suppose that the vehicle is from the momentt k Start to reduce the decelerationj min Reducing acceleration toa expect Then bya expect Making uniform deceleration movement until the speed is reduced tov const2 Obtaining the displacement of the vehicles estimate . The motion model of the estimation process of this step is the same as the third constant velocity mode.
3. If the estimated vehicle is movings estimate Satisfy the following requirementss estimate <s thb -ε，s thb Representing a distance value of the speed limit curve corresponding to the first speed limit end value to the second speed limit end value,εis a pre-preparationSetting margin parameters，Then it is indicated that the vehicle speed has fallen tov const2 Not yet arrive ats thb When the vehicle arrivess thb When the vehicle speed is smaller thanv const2 Thus allowing the vehicle to continue to accelerate tot k+1 And re-estimating, and returning to the step 2.
4. If the estimated vehicle is movings estimate Satisfy the following requirementss thb -ε≤s estimate <s thb Indicating that the vehicle arrivess thb At a speed less than but very close to v const2 Thus the vehicle accelerates to the momentt k It is appropriate to restart the acceleration reduction. So the output timet k From the moment of timet k And firstly, carrying out subsequent speed planning by adopting a planning strategy of a third uniform speed mode.
5. If the estimated vehicle is movings estimate Satisfy the following requirementss estimate >s thb Indicating that the vehicle arrivess thb The time speed will be greater thanv const2 Therefore, the vehicle can only accelerate to the momentt k-1 The acceleration should start to decrease. So the output timet k-1 From the moment of timet k-1 And firstly, carrying out subsequent speed planning by adopting a planning strategy of a third uniform speed mode.
Through the steps, the method can be used for controlling the timet k In determining an optimal time when the vehicle begins to slow downt best Further according tot best And (3) planning the speed of the vehicle, and controlling the vehicle to accelerate and then decelerate.
Eighteenth step: and if the vehicle is in an accelerating state currently, performing speed planning through a fourth downhill mode or a fifth downhill mode as follows.
Fourth downhill mode: and when the current speed of the vehicle is greater than or equal to the high-speed threshold value, planning the acceleration and the speed of the vehicle in a future preset time period through a second downhill mode.
Fifth downhill mode: and when the current speed of the vehicle is smaller than the high-speed threshold value, planning the acceleration and the speed of the vehicle in a future preset time period through a third downhill mode.
Specifically, if the host vehicle is currently in an accelerating state, to prevent the vehicle speed from exceeding the limit speed, a height threshold is usedv high As a boundary line as to whether or not the acceleration should start to be reduced. It should be noted that the present embodiment employs a high-speed thresholdv high Rather than a low speed thresholdv low The boundary line is to prevent the vehicle from frequently switching between the two states of increasing and decreasing acceleration, because in the second downhill mode, it has been defined that if the current speed of the vehicle is smaller thanv low The acceleration starts to increase. Thus, in the present embodiment, when the current speed of the host vehicle is equal to or higher than the high speed threshold valuev high When the initial speed is larger, the vehicle is slowly decelerated to a second downhill mode, and the acceleration and the speed of the vehicle in a future preset time period are planned. When the current speed of the vehicle is less than the high speed thresholdv high And when the vehicle is in a preset time period in the future, the acceleration and the speed of the vehicle can be planned by directly jumping to the third downhill mode.
Specifically, in an embodiment, if in a preset time period in the future, a speed limiting mode corresponding to each path point of a front path of the vehicle is a constant speed mode, a downhill mode and a constant speed mode, and the vehicle speed planning method based on speed limiting information provided by the embodiment of the invention further includes the following steps:
Nineteenth step: estimating the distance travelled by the vehicle during decelerationd proper 。
Twenty steps: calculating theoretical optimal deceleration positions proper_raw Whereins proper_raw =s th2 -d proper ，s th2 Representing the displacement of the second speed limit extremity on the path.
Step twenty-one: calculating an optimal start deceleration positions proper Whereins proper = min(s proper_raw ,s th1 )，s th1 Representing the displacement of the first speed limit extremity on the path.
Twenty-two steps: when the vehicle is displaced s<s proper When the speed limiting method is used, the first speed limiting end value is used for replacing a constant speed limiting value in a constant speed mode, and the speed planning is carried out on the vehicle by adopting the constant speed mode; when the displacement s of the vehicle is more than or equal tos proper And when the vehicle is in a downhill mode, the speed planning is carried out on the vehicle.
Specifically, when changing from the uniform mode to the downhill mode and then to the uniform mode, the embodiment of the present invention defines this special case as a trapezoidal mode. In order to simplify the logic of the speed planning as much as possible, the speed strategy already provided in the above embodiments is used here, i.e. the speed planning of the trapezoid mode is broken down into a combined speed planning of the uniform speed mode and the downhill mode. As shown in fig. 7, the final objective of the speed plan is displacement of the vehicle on the path to the second limit thresholds th2 When the speed is reduced to the second speed limit end valuev const2 Assuming that the speed of the vehicle is from a first speed limit v const1 To reduce tov const2 The distance to be travelled isd proper If it can calculated proper To control the vehicle from positions th2 -d proper The vehicle speed and acceleration fluctuation times can be obviously reduced by starting to decelerate, and the driving comfort is improved.
Based on this, the present embodiment first assumes that the vehicle initially has a first speed limit threshold at speedv const1 Acceleration of 0m/s 2 In which the vehicle is driven in a state of decelerationj min Reducing the acceleration to a preset maximum decelerationa min Then making uniform deceleration movement until the speed is reduced tov const2 . For this assumption, the present embodiment estimates the distance traveled by the vehicle during the entire deceleration asd proper Thereby obtaining the position of the vehicles th2 -d proper Starting to reduce the speed optimally, recording that the theoretical optimal speed reduction position iss proper_raw =s th2 -d proper . Due tos proper_raw Displacement on the path which may be greater than the first limit thresholds th1 So that the optimal starting deceleration position of the vehicle is takens proper_raw Ands th1 smaller position in (2)
s proper = min(s proper_raw ,s th1 )
Then, according to the estimated optimal deceleration positions proper When the vehicle is displaced s<s proper In this case, a speed planning method using a constant speed limiting mode (and using a first speed limiting threshold valuev const1 Replacing constant speed limit in constant speed modev const ) The method comprises the steps of carrying out a first treatment on the surface of the When the displacement s of the vehicle is more than or equal tos proper When the speed planning method of the downhill mode is adopted, the effects of obviously reducing the fluctuation times of the speed and the acceleration of the vehicle and improving the driving comfort are achieved.
Through the steps, the technical scheme provided by the application has the following advantages:
according to the technical scheme, when each speed planning period starts, a plurality of path points are arranged on a preset length section of a front path of the vehicle at equal intervals; then, giving an initial speed limit value to each path point based on the speed limit requirement information of the path; then updating the initial speed limit value of each path point based on the obstacle information in front of the vehicle to obtain the latest speed limit value of each path point; then, connecting and drawing a speed limiting curve with speed limiting values continuously changing along with the distance extension on a road section with a preset length through the latest speed limiting values of all the path points; finally, comprehensively planning the acceleration and the speed of the vehicle in a preset time period based on a speed limit curve so as to enable the speed of the vehicle to be close to the speed limit curve; after the current speed planning period, the current period planning is finished, the first step is returned to set a plurality of path points on the road section with the preset length in front of the vehicle again, and the next speed planning period is entered. Through the steps, the overall speed of the vehicle is closely close to the speed limiting curve, and the speed limiting curve has the effect of stable change at each point of the path, so that the vehicle can run at the maximum speed, the situation of instantaneous abrupt increase and abrupt decrease of the speed of the vehicle can be hardly caused, and the comfort level of drivers and passengers can be remarkably improved.
In addition, the speed planning method provided by the embodiment of the invention has low time complexity: the time complexity of generating the speed limit information isO(n s n static_obs +n s n moving_obs k moving_obs ) The time complexity of the speed planning isO(n s 2 ) Whereinn s For the number of path points,n static_obs is the number of the static barriers to be used,n moving_obs for the number of traversing/reversing obstacles,k moving_obs in order to estimate the collision point of the vehicle and the moving obstacle, the number of the positions of the obstacle in a certain time range is considered. In addition, the speed planning method provided by the embodiment of the invention has strong expandability, and can meet the new demand by only expressing the new demand as the speed limiting point and combining with the original speed limiting point.
As shown in fig. 8, the present embodiment further provides a vehicle speed planning device based on speed limit information, where the device includes:
the route point module 101 is configured to set a plurality of route points at equal intervals on a preset length of a route section in front of the host vehicle. For details, refer to the related description of step S101 in the above method embodiment, and no further description is given here.
The speed limit configuration module 102 is configured to read speed limit requirement information of the current path, and assign an initial speed limit value to each path point based on the speed limit requirement information. For details, refer to the related description of step S102 in the above method embodiment, and no further description is given here.
And the speed limit updating module 103 is used for acquiring the obstacle information in front of the vehicle, and updating the initial speed limit value of each path point based on the obstacle information to obtain the latest speed limit value of each path point. For details, see the description of step S103 in the above method embodiment, and the details are not repeated here.
And the speed limit curve module 104 is used for generating a speed limit curve with speed limit values continuously changing along with the distance extension on the road section with the preset length through the latest speed limit values of the path points. For details, refer to the related description of step S104 in the above method embodiment, and no further description is given here.
The speed planning module 105 is configured to comprehensively plan the acceleration and the speed of the host vehicle in a preset time period in the future, so that the speed of the host vehicle changes according to a speed limit curve in the preset time period in the future. For details, see the description of step S105 in the above method embodiment, and the details are not repeated here.
And the planning period jump module 106 is used for returning to the step of equally setting a plurality of path points on the preset length section of the front path of the host vehicle after the current speed planning period passes, and entering the next speed planning period. For details, refer to the related description of step S106 in the above method embodiment, and no further description is given here.
The vehicle speed planning device based on the speed limit information provided by the embodiment of the invention is used for executing the vehicle speed planning method based on the speed limit information provided by the embodiment, the implementation mode is the same as the principle, and details are referred to the related description of the embodiment of the method and are not repeated.
Fig. 9 shows a domain controller according to an embodiment of the present invention, which at least includes a sensing processing unit 901, a decision processing unit 902, a control processing unit 903, and a communication unit 904, where the sensing processing unit 901, the decision processing unit 902, the control processing unit 903, and the communication unit 904 may be communicatively connected to each other by a bus or other manners, and in fig. 9, the bus manner is taken as an example.
In this embodiment, the sensing processing unit 901 and the decision processing unit 902 respectively include independent processors, and the sensing processing unit 901 and the decision processing unit 902 may respectively include independent memories, or may use shared memories.
In the embodiment of the present invention, the sensing processing unit 901 is mainly applied to a scene of an engineering machine, and mainly functions to perform sensing fusion processing on sensor data to obtain environmental information of an environment where the current engineering machine is located, and then send the environmental information to the control processing unit 903 or the decision processing unit 902 according to a data type of an environmental information signal.
The memory is used as a non-transitory computer readable storage medium for storing non-transitory software programs, non-transitory computer executable programs, and modules, such as program instructions/modules corresponding to the methods in the method embodiments described above. The perception processing unit 901 executes various functional applications of the processor and data processing, i.e. implements the method in the above-described method embodiments, by running non-transitory software programs, instructions and modules stored in the memory.
The decision processing unit 902 functions as: after information fusion of surrounding environment, operation scene, vehicle state and the like is combined, a driving or operation strategy is formulated, and finally a control command is sent.
The main functions of the control processing unit 903 are: conversion between different types of signals of communication protocol conversion (CAN, ethernet, LIN, etc.), AD conversion (sensor input), DA conversion (control drive), etc. For example, the control processing unit 903 may be an MCU of a texas instrument TI chip TDA4VM, an MCU of an eye q series chip of israel mobileey company, an MCU of a japan rapeser-CAR chip R-CAR H3, an MCU of a chinese horizon company, or the like, which converts a signal scanned by the lidar into point cloud data.
The main functions of the communication unit 904 are: the wireless communication is performed, the communication mode includes but is not limited to 5G/4G network communication, wi-Fi communication and satellite communication, and the communication with the cloud server is performed, and the communication method mainly has the following effects: uploading the relevant state and information of the equipment to a cloud service, requesting a cloud server to assist in calculation processing, and downloading data through the cloud server to upgrade OTA software of the controller; communicating with nearby devices, the status of other devices can be received, and the job tasks can be completed cooperatively. The communication unit 110 of the control module may be a 5G module, a Wi-Fi module, a bluetooth module, etc.
It will be appreciated by those skilled in the art that implementing all or part of the above-described methods in the embodiments may be implemented by a computer program for instructing relevant hardware, and the implemented program may be stored in a computer readable storage medium, and the program may include the steps of the embodiments of the above-described methods when executed. The storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a Flash Memory (Flash Memory), a Hard Disk (HDD), or a Solid State Drive (SSD); the storage medium may also comprise a combination of memories of the kind described above.
Although embodiments of the present invention have been described in connection with the accompanying drawings, various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the invention, and such modifications and variations are within the scope of the invention as defined by the appended claims.

Claims (11)

1. A vehicle speed planning method based on speed limit information, the method comprising:
a plurality of route points are arranged on a preset length section of a front route of the vehicle at equal intervals;
the speed limiting requirement information of the current path is read, and initial speed limiting values are given to all path points based on the speed limiting requirement information;
acquiring barrier information in front of the vehicle, and updating initial speed limit values of all path points based on the barrier information to obtain the latest speed limit values of all the path points;
generating a speed limit curve with speed limit values continuously changing along with the distance extension on the preset length road section through the latest speed limit values of all the path points;
comprehensively planning the acceleration and the speed of the vehicle in a preset time period in the future so as to change the speed of the vehicle in the preset time period in the future according to the speed limiting curve;
and after the current speed planning period, returning to the step of arranging a plurality of path points on the preset length section of the front path of the vehicle at equal intervals, and entering the next speed planning period.
2. The method of claim 1, wherein updating the initial speed limit value for each waypoint based on the obstacle information to obtain the latest speed limit value for each waypoint comprises:
when the obstacle information indicates that the front of the vehicle has a static obstacle, calculating the latest speed limit value corresponding to each path point capable of enabling the vehicle to stop at a first preset distance position in front of the static obstacle;
when the obstacle information indicates that a traveling obstacle passing through a path of the vehicle exists in front of the vehicle, estimating traveling collision points of the vehicle and the traveling obstacle, and calculating the latest speed limit value of each path point in front of the vehicle by taking the traveling collision points as static obstacles;
when the obstacle information indicates that a reverse obstacle exists in front of the vehicle, estimating a reverse collision point of the vehicle and the reverse obstacle, and calculating the latest speed limit value of each path point in front of the vehicle by taking the reverse collision point as a static obstacle;
when the obstacle information indicates that the front of the vehicle has a vehicle following obstacle needing to follow the vehicle, determining a minimum vehicle following distance and a maximum vehicle following distance;
when the distance between the vehicle and the following obstacle is between the minimum following distance and the maximum following distance, calculating the latest speed limit value of each path point in front of the vehicle by the following method
Figure QLYQS_1
Figure QLYQS_2
In the method, in the process of the invention,
Figure QLYQS_3
for a preset maximum deceleration of the vehicle during normal driving,/->
Figure QLYQS_4
Computing the best for current participationThe distance from the path point of the new speed limit value to the vehicle following obstacle,v follow equal to the travel speed of the following obstacle;
when the distance between the vehicle and the following obstacle is smaller than the minimum following distance, calculating the latest speed limit value of each path point in front of the vehicle according to the following formula
Figure QLYQS_5
Figure QLYQS_6
In the method, in the process of the invention,c times is a preset scaling parameter greater than 1;
when the distance between the vehicle and the following obstacle is greater than the maximum following distance, calculating the latest speed limit value of each path point in front of the vehicle by adopting the following formula
Figure QLYQS_7
Figure QLYQS_8
/>
In the method, in the process of the invention,
Figure QLYQS_9
representing the maximum following distance.
3. The method of claim 2, wherein estimating the travel collision point of the host vehicle with the travel obstacle comprises:
estimating each arrival time when the vehicle arrives at any position in front at the current speed at constant speed;
based on the running track of the passing obstacle, starting from the current position of the vehicle, testing whether the vehicle collides with the passing obstacle at a certain position in front one by one, and taking the first collision position obtained by testing as the passing collision point;
wherein the steps of each test include:
Extracting target arrival time of the vehicle reaching the current test position from each arrival time;
if the passing obstacle passes the current test position in a preset second before and after the target arrival time, taking the current test position as a collision position;
and if the distance between the passing obstacle and the current test position at the target arrival time is within a second preset distance, taking the current test position as a collision position.
4. The method of claim 1, wherein generating the speed limit curve having the speed limit continuously varying with the distance over the preset length of the road segment by the latest speed limit value of each of the route points comprises:
taking the extending distance of the road section with the preset length as a horizontal axis and taking the latest speed limiting value as a vertical axis, and generating a speed limiting curve based on the latest speed limiting value connection of each path point;
replacing a curve part with a speed-down curve part in the speed-limit curve by using a line segment formed by connecting a speed-down starting endpoint and a speed-down stopping endpoint;
replacing a curve part with a speed rising curve from a speed starting rising endpoint to a speed stopping rising endpoint in the speed limiting curve;
And identifying the shape of the regulated speed limit curve, and dividing the speed limit curve into three speed limit modes, namely a constant speed mode, a step mode and a downhill mode based on the identified shape, wherein the constant speed mode represents a linear part with constant speed limit values, the step mode represents a part with jump from one constant speed limit value to another constant speed limit value, and the downhill mode represents a linear part with linear descent from one speed limit value to another speed limit value.
5. The method according to claim 4, wherein if the speed limit mode corresponding to each path point of the front path of the host vehicle is a constant speed mode in the future preset time period, the comprehensively planning the acceleration and the speed of the host vehicle in the future preset time period includes:
first uniform velocity mode: when the current speed of the vehicle is equal to a constant speed limit value and the current acceleration of the vehicle is equal to 0, planning that the speed of the vehicle at each moment in a preset time period in the future is the constant speed limit value, and planning that the acceleration of the vehicle at each moment in the preset time period in the future is 0;
second constant speed mode: when the current speed of the vehicle is smaller than the constant speed limit value, or the current speed of the vehicle is equal to the constant speed limit value and the current acceleration of the vehicle is smaller than 0, controlling the vehicle to perform variable acceleration driving according to the uniform acceleration in a preset time period in the future; when the acceleration of the vehicle is increased to a preset maximum acceleration, controlling the vehicle to run at the preset maximum acceleration in a uniform acceleration manner until the speed of the vehicle reaches v const -v gap Whereinv const Represents the constant-speed limit value,v gap representing a preset speed interval parameter; when the speed reachesv const -v gap Then, controlling the vehicle to follow the acceleration at each remaining moment of a preset time period in the futurea w =a max (v const -v w-1 )/v gap To perform variable acceleration running in whicha w Indicating the acceleration of the own vehicle at the current moment,a max representing the preset maximum acceleration of the vehicle,v w-1 indicating the speed of the vehicle at one moment;
third constant speed mode: when the current speed of the vehicle is greater than the constant speed limit value, or the current speed of the vehicle is equal to the constant speed limit value and the current acceleration of the vehicle is greater than 0, controlling the vehicle to run at variable speed according to uniform reduction of the acceleration in a preset time period in the future; when the acceleration of the vehicle is reduced to a preset maximum deceleration, controlling the vehicle to run at uniform deceleration with the preset maximum deceleration until the speed of the vehicle reachesv const +v gap Whereinv const Represents the constant-speed limit value,v gap representing a preset speed interval parameter; when the speed reachesv const +v gap Then, controlling the vehicle to follow the acceleration at each remaining moment of a preset time period in the futurea w =a min (v w-1 -v const )/v gap Running at variable speed, in whicha w Indicating the acceleration of the own vehicle at the current moment,a min representing the preset maximum deceleration rate in question,v w-1 indicating the speed of the host vehicle at a time.
6. The method according to claim 5, wherein if the speed limit mode corresponding to each path point of the path in front of the host vehicle is a step mode in the future preset time period, the comprehensively planning the acceleration and the speed of the host vehicle in the future preset time period includes:
step path points with speed limit values changed in step are determined from the path points;
before the step path point, carrying out constant speed mode planning on the acceleration and the speed of the vehicle in a future preset time period based on a constant speed limit value before the step;
and after the step path point, carrying out constant speed mode planning on the acceleration and the speed of the vehicle in a future preset time period based on the constant speed limit value after the step.
7. The method according to claim 5, wherein if the speed limit mode corresponding to each path point of the path in front of the host vehicle is a downhill mode in the future preset time period, the comprehensively planning the acceleration and the speed of the host vehicle in the future preset time period includes:
determining a first speed limit end value and a second speed limit end value, wherein the first speed limit end value is a speed limit value corresponding to an end point of a speed limit curve for starting speed reduction, and the second speed limit end value is a speed limit value corresponding to an end point of the speed limit curve for stopping speed reduction; a high-speed threshold value and a low-speed threshold value are respectively taken between the first speed limiting end value and the second speed limiting end value and are used for representing the speed condition of the vehicle; calculating standard acceleration corresponding to the deceleration from the first speed limit end value to the second speed limit end value;
If the vehicle is in a deceleration or uniform speed state at present, speed planning is carried out through a first downhill mode, a second downhill mode or a third downhill mode as follows;
first downhill mode: when the current speed of the vehicle is greater than or equal to the first speed limit end value, calculating a first deceleration by the following formula
a start_const2 = max(a start_const2_raw ,a min )
a start_const2_raw = (v const2 +v 0 )(v const2 -v 0 )/(2s thb )
In the method, in the process of the invention,a start_const2 which represents the first deceleration rate in question,v const2 representing the second limit value of the speed limit,v 0 indicating the current speed of the host vehicle,s thb representing a distance value of the speed limit curve corresponding to the first speed limit end value to the second speed limit end value,a min representing the preset maximum deceleration rate in question,a start_const2_raw representing a first initial deceleration;
respectively replacing preset maximum deceleration and constant speed limiting values in the third constant speed mode by using the first deceleration and the second speed limiting end value, and planning the acceleration and the speed of the vehicle in a future preset time period by using the third constant speed mode with the replaced parameters;
a second downhill mode: when the current speed of the vehicle is greater than or equal to the low speed threshold value and less than the first speed limiting end value, calculating a second deceleration by the following formula
a suitable = max(a suitable_raw , a min )
a suitable_raw =a const (v 0 - v low )/(v const1 - v low )
In the method, in the process of the invention,v 0 indicating the current speed of the host vehicle,v low representing the low-speed threshold value in question,v const1 representing the first limit value of the speed limit, a const Which is indicative of the standard acceleration of the vehicle,a min representing the preset maximum deceleration rate in question,a suitable which represents the second deceleration rate in question,a suitable_raw representing a second initial deceleration;
respectively replacing a preset maximum deceleration and a constant speed limit value in the third constant speed mode by using the second deceleration and the second speed limit value, and planning the acceleration and the speed of the vehicle in a future preset time period by using the third constant speed mode with the replaced parameters;
third downhill mode: when the current speed of the vehicle is smaller than the low-speed threshold value, controlling the vehicle to accelerate and decelerate firstly;
if the vehicle is in an accelerating state currently, speed planning is carried out through a fourth downhill mode or a fifth downhill mode as follows;
fourth downhill mode: when the current speed of the vehicle is greater than or equal to the high-speed threshold value, planning the acceleration and the speed of the vehicle in a future preset time period through the second downhill mode;
fifth downhill mode: and when the current speed of the vehicle is smaller than the high-speed threshold value, planning the acceleration and the speed of the vehicle in a future preset time period through the third downhill mode.
8. The method of claim 7, wherein if the speed limit mode corresponding to each of the path points of the own vehicle front path is a constant speed mode plus a downhill mode plus a constant speed mode within a predetermined time period in the future, the method further comprises:
Estimating the distance travelled by the vehicle during decelerationd proper The method comprises the steps of carrying out a first treatment on the surface of the Calculating theoretical optimal deceleration positions proper_raw Whereins proper_raw =s th2 -d proper ，s th2 Representing the secondDisplacement of the speed limiting end value on the path;
calculating an optimal start deceleration positions proper Whereins proper = min(s proper_raw , s th1 )，s th1 Representing the displacement of the first speed limit end value on the path;
when the vehicle is displaced s<s proper When the speed limiting method is used, the first speed limiting end value is used for replacing a constant speed limiting value in a constant speed mode, and the speed planning is carried out on the vehicle by adopting the constant speed mode; when the displacement s of the vehicle is more than or equal tos proper And when the vehicle is in a downhill mode, the speed planning is carried out on the vehicle.
9. A vehicle speed planning apparatus based on speed limit information, the apparatus comprising:
the route point module is used for arranging a plurality of route points at equal intervals on a preset length section of a route in front of the host vehicle;
the speed limit configuration module is used for reading the speed limit requirement information of the current path and giving an initial speed limit value to each path point based on the speed limit requirement information;
the speed limit updating module is used for acquiring obstacle information in front of the vehicle, updating initial speed limit values of all the path points based on the obstacle information, and obtaining the latest speed limit values of all the path points;
the speed limit curve module is used for generating a speed limit curve with speed limit values continuously changing along with the distance extension on the preset length road section through the latest speed limit values of all the path points;
The speed planning module is used for comprehensively planning the acceleration and the speed of the vehicle in a preset time period in the future so as to change the speed of the vehicle in the preset time period in the future according to the speed limiting curve;
and the planning period jumping module is used for returning to the step of arranging a plurality of path points on the preset length section of the front path of the vehicle at equal intervals after the current speed planning period is passed, and entering the next speed planning period.
10. A domain controller, comprising: -a perception processing unit, a decision processing unit, a control processing unit and a communication unit, said perception processing unit, said decision processing unit, said control processing unit and said communication unit being communicatively connected to each other, said decision processing unit having stored therein computer instructions, said decision processing unit executing the method according to any of claims 1-8 by executing said computer instructions.
11. A computer readable storage medium storing computer instructions for causing a computer to perform the method of any one of claims 1-8.
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