CN115071699A - Intelligent automobile lane changing collision avoidance control method - Google Patents
Intelligent automobile lane changing collision avoidance control method Download PDFInfo
- Publication number
- CN115071699A CN115071699A CN202210812001.0A CN202210812001A CN115071699A CN 115071699 A CN115071699 A CN 115071699A CN 202210812001 A CN202210812001 A CN 202210812001A CN 115071699 A CN115071699 A CN 115071699A
- Authority
- CN
- China
- Prior art keywords
- vehicle
- control method
- distance
- obstacle
- collision avoidance
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 65
- 230000008859 change Effects 0.000 claims abstract description 6
- 238000004364 calculation method Methods 0.000 claims description 21
- 230000007246 mechanism Effects 0.000 claims description 3
- 230000008569 process Effects 0.000 description 13
- 230000001133 acceleration Effects 0.000 description 7
- 238000004422 calculation algorithm Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 238000004458 analytical method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 241000084490 Esenbeckia delta Species 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000010485 coping Effects 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Images
Classifications
-
- 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
- B60W30/08—Active safety systems predicting or avoiding probable or impending collision or attempting to minimise its consequences
- B60W30/09—Taking automatic action to avoid collision, e.g. braking and steering
-
- 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
- B60W30/08—Active safety systems predicting or avoiding probable or impending collision or attempting to minimise its consequences
- B60W30/095—Predicting travel path or likelihood of collision
- B60W30/0953—Predicting travel path or likelihood of collision the prediction being responsive to vehicle dynamic parameters
-
- 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
- B60W50/00—Details of control systems for road vehicle drive control not related to the control of a particular sub-unit, e.g. process diagnostic or vehicle driver interfaces
- B60W50/0098—Details of control systems ensuring comfort, safety or stability not otherwise provided for
-
- 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
- B60W60/00—Drive control systems specially adapted for autonomous road vehicles
- B60W60/001—Planning or execution of driving tasks
- B60W60/0015—Planning or execution of driving tasks specially adapted for safety
-
- 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
- B60W50/00—Details of control systems for road vehicle drive control not related to the control of a particular sub-unit, e.g. process diagnostic or vehicle driver interfaces
- B60W2050/0001—Details of the control system
- B60W2050/0019—Control system elements or transfer functions
-
- 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
- B60W2520/00—Input parameters relating to overall vehicle dynamics
- B60W2520/06—Direction of travel
-
- 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
- B60W2520/00—Input parameters relating to overall vehicle dynamics
- B60W2520/10—Longitudinal speed
-
- 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
- B60W2520/00—Input parameters relating to overall vehicle dynamics
- B60W2520/10—Longitudinal speed
- B60W2520/105—Longitudinal acceleration
-
- 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
- B60W2520/00—Input parameters relating to overall vehicle dynamics
- B60W2520/12—Lateral speed
- B60W2520/125—Lateral acceleration
-
- 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
- B60W2554/80—Spatial relation or speed relative to objects
- B60W2554/801—Lateral distance
-
- 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
- B60W2554/80—Spatial relation or speed relative to objects
- B60W2554/802—Longitudinal distance
Landscapes
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Human Computer Interaction (AREA)
- Steering Control In Accordance With Driving Conditions (AREA)
Abstract
The application discloses an intelligent automobile lane change collision avoidance control method, which comprises the following steps: step 1, collecting vehicle state information and obstacle distance information; step 2, judging whether a first switching condition is met or not according to the vehicle state information and the obstacle distance information, and if not, executing step 3; if yes, executing step 4; step 3, when the controllability constraint is judged to be met, entering a first-stage control method, and calculating front wheel steering angle feedback and rear wheel torque feedback; when the controllability constraint is judged not to be met, entering a second-stage control method, and calculating front wheel steering angle feedback; and 4, entering a third-stage control method when the second switching condition is judged to be met, and entering a second-stage control method and calculating front wheel steering angle feedback when the second switching condition is judged not to be met. Through the technical scheme in the application, the danger avoiding capability of steering collision avoidance auxiliary driving is widened, and the requirement of an emergency steering collision avoidance system on the longitudinal collision avoidance distance is reduced.
Description
Technical Field
The application relates to the technical field of automatic driving, in particular to an intelligent automobile lane changing collision avoidance control method.
Background
In the traditional control method in automatic driving, or because a planned path can be tracked, or because of conservative vehicle stability limitation, and the like, under some extreme dangerous working conditions, such as encountering that pedestrians in a short distance suddenly break into a road, the traditional lane-changing collision avoidance control method cannot smoothly complete emergency collision avoidance because the limit operation performance of an automobile is limited.
For example, in the published patent CN110723142A, the solution for lane change collision avoidance technology is: firstly, a lane changing track is constructed based on a fifth-order polynomial, and then the vehicle is controlled to track the track. During the track planning, calculating the centripetal acceleration of each point by the second-order derivation of a fifth-order polynomial, and calculating the centripetal acceleration limit a ymax The curvature of each point on the path is constrained to a limit of 0.28g to ensure that the planned path can be traced.
The lane changing collision avoidance method limits the ultimate handling performance of the vehicle, has good effect on the collision avoidance working condition under the common condition, but has some limitations on the collision avoidance working condition with a short longitudinal distance such as a ghost probe. The specific analysis is as follows:
in the early stage of the whole lane changing collision avoidance process, the vehicle has collision risks, and in the later stage, after the vehicle and the obstacle do not have an overlapping area, the lane keeping function is similar. Therefore, the emergency degree of the whole process is from high to low, operability can be obtained by properly sacrificing stability in the early stage according to the emergency degree, and the vehicle can be returned to be stable and enter a side lane after no collision risk in the later stage. It is clear that the above-described approach of mathematical path planning based on a quintic polynomial cannot take these into account.
Disclosure of Invention
The purpose of this application lies in: the control method is designed with the aim of exerting the limit capacity of the automobile, so that the danger avoiding capacity of steering collision avoidance auxiliary driving is widened, and the requirement of an emergency steering collision avoidance system on the longitudinal collision avoidance distance is reduced.
The technical scheme of the application is as follows: the utility model provides an intelligent automobile lane change collision avoidance control method, which comprises the following steps: step 1, collecting vehicle state information and obstacle distance information; step 2, judging whether a first switching condition is met or not according to the vehicle state information and the obstacle distance information, if not, judging whether a controllability constraint condition is met or not, and executing step 3; if yes, judging whether a second switching condition is met, and executing the step 4; step 3, when the controllability constraint is judged to be met, entering a first-stage control method, and calculating front wheel steering angle feedback and rear wheel torque feedback; when the controllability constraint is judged not to be met, entering a second-stage control method, and calculating front wheel steering angle feedback; step 4, when the second switching condition is judged to be met, entering a third-stage control method, and calculating front wheel steering angle feedback; and when the second switching condition is judged not to be met, entering a second stage control method, and calculating front wheel steering angle feedback.
In any one of the above technical solutions, further, the obstacle distance information includes a distance from a vehicle center of mass to a left end of the obstacle, a distance from the vehicle center of mass to a right end of the obstacle, and a distance from the vehicle center of mass to a terminal end of the obstacle, and the vehicle state information at least includes a vehicle heading angle, in step 2, when the left lane is involved in collision avoidance, the first switching condition is: whether the vehicle heading angle phi is larger than or equal to an arc tangent function value of a first distance ratio, wherein the first distance ratio is the ratio of the distance between the center of mass of the vehicle and the tail end of the obstacle to the distance between the center of mass of the vehicle and the left end of the obstacle; when the right switching lane is in collision avoidance, the first switching condition is as follows: and whether the vehicle heading angle phi is smaller than or equal to an arc tangent function value of a second distance ratio, wherein the second distance ratio is the ratio of the distance between the center of mass of the vehicle and the tail end of the obstacle to the distance between the center of mass of the vehicle and the right end of the obstacle.
In any of the above technical solutions, further, the second switching condition is: the distance from the center of mass of the vehicle to the left end of the obstacle is 0, or the distance from the center of mass of the vehicle to the right end of the obstacle is 0.
In any of the above technical solutions, further, the calculation formula of the controllability constraint condition in step 2 is:
|β front |≤|δ max +α fp |
in the formula, beta front Is the speed direction of the front wheel of the automobile, beta is the centroid slip angle, a is the distance from the centroid of the automobile to the front axle, r is the yaw velocity of the automobile, delta max Maximum front wheel angle, alpha, limited by the steering mechanism fp Is the corresponding tire slip angle at the peak of the tire lateral force.
In any one of the above technical solutions, further, in the first stage control method, a calculation formula for calculating the front wheel steering angle feedback is as follows:
in the formula, delta des For front wheel steering angle feedback, V is total vehicle speed, beta is centroid slip angle, a is distance from centroid to front axle, r is vehicle yaw rate, and alpha fp The tire slip angle corresponding to the peak position of the tire lateral force;
the calculation formula for calculating the rear wheel torque feedback is as follows:
τ command ＝RμF zri cos(β+π/2)
in the formula, τ command For rear wheel torque feedback, R is the wheel radius, μ is the road adhesion coefficient, F zri Is the vertical load of a single wheel of the rear wheel.
In any one of the above technical solutions, further, in the second-stage control method, a calculation formula for calculating the front wheel steering angle feedback is as follows:
in the formula, delta des In order to feed back the front wheel steering angle,v is the total vehicle speed, beta is the centroid slip angle, a is the distance from the centroid to the front axle, and r is the vehicle yaw rate;
in step 3, after entering the second stage control method, the method further comprises:
the rear wheel torque feedback is set to 0.
In any one of the above technical solutions, further, a calculation formula of the tracking error in the third-stage control method is as follows:
in the formula, Y bou Left side lane boundary, Y ref Is the lane centerline and Y is the current vehicle position Y coordinate.
The beneficial effect of this application is:
according to the technical scheme, collision avoidance is divided into three stages according to the danger degree of the whole collision avoidance process, corresponding judgment trigger conditions are set, operation performance is used as the main part when the collision avoidance risk exists in the early stage, part of stability performance is sacrificed, and the stability performance is used as the main part when the collision avoidance risk does not exist in the later stage, so that the vehicle returns to a conservative stability area and tracks the side lane line to run. The limit performance of the vehicle is more fully utilized, and the collision avoidance task can be completed within a shorter longitudinal distance.
Particularly, the optimal steering capacity is pursued by sacrificing part of stability in the early stage, so that the requirement on the longitudinal collision avoidance distance can be reduced, and the capacity of dealing with the obstacle suddenly breaking into the lane at a short distance is stronger.
Drawings
The advantages of the above and/or additional aspects of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
fig. 1 is a schematic flow chart of an intelligent vehicle lane-changing collision avoidance control method according to an embodiment of the present application;
FIG. 2 is a schematic diagram of an initial time of a vehicle collision avoidance according to one embodiment of the present application;
FIG. 3 is a schematic diagram of a first phase and a second phase handover according to an embodiment of the present application;
FIG. 4 is a schematic diagram of a third stage control algorithm according to one embodiment of the present application;
FIG. 5 is a schematic diagram of second and third phase switching according to an embodiment of the present application;
fig. 6 is a schematic diagram of a vehicle end-of-collision time according to an embodiment of the present application.
Detailed Description
In order that the above objects, features and advantages of the present application can be more clearly understood, the present application will be described in further detail with reference to the accompanying drawings and detailed description. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, however, the present application may be practiced in other ways than those described herein, and therefore the scope of the present application is not limited by the specific embodiments disclosed below.
As shown in fig. 1, the embodiment provides an intelligent vehicle lane change collision avoidance control method, which includes:
step 1, vehicle state information and obstacle distance information are collected, wherein the obstacle distance information comprises a distance from a vehicle center of mass to a left end of an obstacle, a distance from the vehicle center of mass to a right end of the obstacle, and a distance from the vehicle center of mass to a tail end of the obstacle, and the vehicle state information at least comprises a vehicle course angle.
Specifically, a vehicle traveling in the same direction in front is set as an obstacle in front of a vehicle to be collided, the area where the vehicle in front is located is expanded, the vehicle is expanded to the left and the right (the vehicle to be collided) by 0.5 time of the width of the vehicle, the vehicle is expanded backwards by the distance from the center of mass of the vehicle to the foremost end of the vehicle head, and the expanded vehicle is regarded as a non-shaped point in collision research.
The vehicle state information collected in this embodiment at least includes the vehicle heading angle phi, the total vehicle speed V and its direction, the vehicle yaw rate r, and the center of massSlip angle beta, longitudinal/lateral acceleration a x And a y 。
As shown in FIG. 2, at the initial moment of collision avoidance, X in the figure d Indicating the distance from the center of mass of the vehicle to the left end of the obstacle after expansion at the initial moment, Y d Represents the distance from the center of mass of the vehicle to the rear end of the obstacle after expansion at the initial moment, and the distance X d 、Y d And the fixed value is acquired and confirmed by the sensor at the initial moment of the collision avoidance process. And delta Y represents the distance from the vehicle center of mass to the left end (or the right end) of the expanded obstacle at each moment in the collision avoidance process, delta X represents the distance from the vehicle center of mass to the rear end of the expanded obstacle at each moment in the collision avoidance process, and the distances delta X and delta Y are updated in real time along with the collision avoidance process and are acquired by a sensor in real time.
Step 2, judging whether a first switching condition is met or not according to the collected vehicle state information and the collected obstacle distance information, if not, judging whether a controllability constraint condition is met or not, and executing step 3; if yes, judging whether a second switching condition is met, and executing the step 4.
When the left switching channel is in collision avoidance, the first switching condition is as follows: whether the vehicle course angle phi is larger than or equal to the arc tangent function value of the first distance ratio or not, and the corresponding calculation formula is as follows:
φ≥arctan(ΔX/ΔY)
in the formula, phi is a vehicle heading angle, delta X is the distance between the center of mass of the vehicle and the tail end of the obstacle, and delta Y is the distance between the center of mass of the vehicle and the left end of the obstacle;
when the right switching lane is in collision avoidance, the first switching condition is as follows: whether the vehicle heading angle phi is smaller than or equal to the arctangent function value of the second distance ratio or not, namely, the inequality sign in the vehicle heading angle calculation formula is more than or equal to the inequality sign and is adjusted to be less than or equal to the inequality sign, and delta Y is the distance from the center of mass of the vehicle to the right end of the obstacle.
It should be noted that the origin of the rectangular plane coordinate system where the vehicle heading angle phi is located is the center of mass of the vehicle, and the traveling direction is the positive direction of the x-axis.
The calculation formula corresponding to the controllability constraint condition is as follows:
|β front |≤|δ max +α fp |
in the formula, beta front The speed direction of the front wheel of the automobile is obtained by converting information measured by a sensor, beta is a mass center slip angle, a is the distance from the mass center of the automobile to a front shaft, r is the yaw velocity of the automobile, and delta max The maximum front wheel steering angle limited by the steering mechanism is a set value, alpha fp The tire cornering angle corresponding to the peak of the tire cornering force is determined by the tire cornering characteristics.
Wherein the second switching condition is: the distance from the center of mass of the vehicle to the left end or the right end of the obstacle is 0, namely: Δ Y ═ 0.
When the vehicle meets the second switching condition, it means that the vehicle no longer has an overlap area with the obstacle and the vehicle has no risk of collision.
The present embodiment will now be described with reference to left-turn collision avoidance as an example.
Step 3, when the controllability constraint is judged to be met, entering a first-stage control method, and calculating front wheel steering angle feedback and rear wheel torque feedback; and when the controllability constraint is judged not to be met, entering a second-stage control method, and calculating the front wheel steering angle feedback.
Specifically, when a collision avoidance assistance driving system in the intelligent automobile is activated, a sensor arranged in the intelligent automobile starts to acquire vehicle state information and obstacle distance information, and the whole collision avoidance process is divided into three stages from the beginning.
The first stage is mainly collision avoidance, and the vehicle is controlled to turn based on the maximum adhesion force provided by the tires on the road surface, and the vehicle course angle is changed in the shortest time. The calculation formula of the front wheel steering angle feedback is as follows:
in the formula, delta des For front wheel steering feedback, V is the speed at the vehicle centroidDegree (total vehicle speed), beta is the centroid slip angle, a is the distance from the centroid to the front axle, r is the vehicle yaw rate, alpha fp The tire cornering angle corresponding to the peak of the tire cornering force is determined by the tire cornering characteristics.
The calculation formula of the rear wheel torque feedback is as follows:
τ command ＝RμF zri cos(β+π/2)
in the formula, τ command For rear wheel torque feedback, R is the wheel radius, μ is the road adhesion coefficient, F zri For the vertical load of a single wheel of the rear wheel, the corresponding calculation formula is:
wherein b is the distance from the center of mass of the vehicle to the rear axle, a is the distance from the center of mass to the front axle, m is the total vehicle mass of the vehicle, g is the acceleration of gravity, and h s Is the height of the center of mass, t w For both left and right vehicle track, a x 、a y The acceleration is measured by the sensor for the longitudinal and lateral acceleration of the vehicle.
And in the first stage, the front wheel steering angle feedback and the rear wheel torque feedback are obtained and then used as vehicle system input of the next control cycle to carry out vehicle collision avoidance control.
As shown in fig. 3, the vehicle speed of the vehicle to be collided is determined by the existing collision avoidance method based on the front wheel steering angle feedback and the rear wheel torque feedback, and at this time, the extension line of the vehicle speed vector V does not intersect with the obstacle after the expansion processing.
In the present embodiment, when the vehicle heading angle satisfies the first switching condition, which represents that the vehicle heading angle has increased to an angle sufficient to avoid the obstacle, the vehicle does not collide with the obstacle even if the steering is no longer continued. At this time, it is necessary to switch to the second stage or the third stage.
The second stage is a transition stage, because at the end of the first stage, the vehicle heading angle phi is increased enough to avoid the obstacle, but through verification and summary of a large number of collision avoidance algorithms, it is found that the vehicle to be avoided may still have an overlapping area with the obstacle (i.e. delta Y is more than or equal to 0), if the vehicle is controlled to enter the next lane at this time, since the whole lane changing collision avoidance process is a process of turning left and then turning right, the control algorithm for controlling the vehicle to be avoided (the own vehicle) to enter the next lane may reverse the steering wheel of the own vehicle, so that the heading angle is adjusted back, the vehicle heading angle phi is reduced, and the vehicle collides with the vehicle (the obstacle) in front, so that the collision avoidance fails. Therefore, when the first switching condition is satisfied, the second stage is required to be introduced to perform the transition of collision avoidance control.
The control targets in the second stage are: and adjusting front wheel angle feedback and rear wheel torque feedback to perform vehicle collision avoidance control so as to ensure that the vehicle to be collided is only subjected to a leftward force perpendicular to the total vehicle speed V direction, has no rightward component force, ensures that the vehicle course angle is not pulled back, and reduces the yaw angular velocity and the mass center slip angle of the vehicle on the premise of ensuring that the vehicle course angle phi is not reduced, so that the vehicle state is stabilized. The calculation formula of the front wheel steering angle feedback is as follows:
at this time, the rear wheel torque feedback is set to 0, i.e.: tau is command ＝0。
Compared with the conventional collision avoidance control algorithm, the second stage in the embodiment has the following advantages:
1) the tire force of the front wheel is always 0, and no backward component force exists, so that the total speed of the bicycle is not greatly reduced, and the risk of rear-end collision of the bicycle is reduced;
2) the self vehicle is only subjected to the lateral force of the rear wheel, and no component force exists in the right direction perpendicular to the vector total vehicle speed V, so that the collision between the self vehicle and an obstacle due to the adjustment of the course angle of the vehicle is avoided.
Step 4, when the second switching condition is judged to be met, entering a third-stage control method, and calculating front wheel steering angle feedback; and when the second switching condition is judged not to be met, entering a second-stage control method and calculating front wheel steering angle feedback.
The third stage in this embodiment is to control the vehicle to enter a side lane for driving, and implement collision avoidance of the vehicle to be collided by using a control algorithm similar to tracking the center line of the left road and lane keeping, as shown in fig. 4, where the distance between the vehicle and the center line of the road is acquired by a sensor.
F in FIG. 4 yf And F yr The front and rear wheel lateral forces are obtained by converting vehicle states such as vehicle speed, acceleration, angular velocity and the like acquired by a sensor according to tire characteristics.
Further, in the third stage, the embodiment optimizes the tracking error in the collision avoidance control process, so that the vehicle to be collided needs to be prevented from colliding with the road boundary besides tracking the lane center line, and the error e is utilized 1 The vehicle is guided to track the center line of the lane, and the corresponding calculation formula is as follows:
e 1 ＝Y-Y ref
using error e 2 The vehicle and the road boundary line are rejected, and the corresponding calculation formula is as follows:
therefore, the calculation formula of the optimized tracking error is as follows:
in the formula, Y bou Left lane boundary after expansion of the obstacle, Y ref Is the lane center line and Y is the position Y coordinate of the current vehicle.
In this embodiment, the course angle error Δ Φ is:
Δφ＝φ-φ ref ＝φ
in the formula, phi ref Is the heading angle of the reference path. Note that the heading angle phi of the reference path ref The heading angle of the left lane center line to be tracked, therefore phi ref Is 0, so the heading angle error delta phi is equal to the vehicle heading angle phi.
In this embodiment, the collision avoidance condition of the vehicle to be collided is an emergency condition occurring within a few seconds, so the influence of the steady-state error of the control system on the control effect of the system can be ignored, but in order to improve the collision avoidance performance of the vehicle in this embodiment, not only the tracking of the center line of the left lane but also the avoidance of collision with the boundary guardrail of the left lane need to be considered, so that the pd control rate is applied to the lateral displacement error e (tracking error after optimization) as follows:
in the formula (I), the compound is shown in the specification,
is pd control rate, k p 、k d Is the corresponding feedback scaling factor.
The error e is differentiated in two orders and is associated with the pd control rate as follows:
at this stage, no longitudinal control is performed, so the total vehicle speed V is substantially unchanged,
the above equation can be further refined as:
then:
in the vehicle dynamics equation, only the yaw rate of the vehicle is involved
Is related to the front wheel steering angle delta, so it is necessary to use the formula
Is converted into
Can utilize the inverse model of vehicle dynamics to reversely calculate the front wheel steering angle feedback delta des . The specific conversion process is as follows:
and performing first-order error proportional feedback control on the centroid slip angle beta, wherein the following formula is adopted:
e β ＝β-β ref ＝β
the simultaneous expression is as follows:
will once expect value r des As a tracking reference, a control rate of a quadratic desired yaw rate is obtained
The corresponding calculation formula is:
e r ＝r-r des
finally, the relation between the upper formula and the lower train kinematics differential equation is utilized
Is combined to solve the desired front wheel steering angle feedback delta des 。
Based on the formula, the front wheel steering angle feedback delta is reversely calculated by utilizing a vehicle dynamics inverse model des And further feeds back a desired front wheel steering angle δ des And the vehicle collision avoidance control is carried out as the vehicle system input of the next control period. The rear wheel torque feedback at this time is 0.
As shown in fig. 5, by switching between the second phase and the third phase, the center of mass of the vehicle and the obstacle have no overlapping area in the lateral direction, and there is no possibility of collision.
As shown in fig. 6, at the end of the collision avoidance control method of this embodiment, the vehicle has already safely entered the left lane to travel, and at this time, the driver is prompted to take over the driving right.
Through analysis, the technical scheme in the embodiment adopts the maximum lateral force of the tire to steer when the first-stage collision avoidance is carried out, and the steering capability is obtained by sacrificing part of the stability performance. Compared with the scheme for planning the collision avoidance track by using the quintic polynomial adopted in the conventional scheme, the technical scheme in the embodiment pursues maneuverability to improve steering capacity when collision avoidance is carried out in the early stage, pursues stability to enable the vehicle state to return to a conservative stable region when collision avoidance is carried out in the later stage, and reasonably utilizes performance resources of the vehicle according to the characteristics of 'collision risk is carried out in the early stage and track line is tracked when collision risk is not carried out in the later stage' in the process of changing the track and avoiding collision. Therefore, the performance of collision avoidance driving assistance can be improved.
Particularly, because partial stability is sacrificed at the early stage and the optimal steering capability is pursued, the requirement on the longitudinal collision avoidance distance can be reduced, and the capability of coping with the obstacle suddenly intruding into the lane at a short distance is stronger.
The technical scheme of the application is explained in detail in the above with reference to the accompanying drawings, and the application provides an intelligent automobile lane change collision avoidance control method, which comprises the following steps: step 1, collecting vehicle state information and obstacle distance information; step 2, judging whether a first switching condition is met or not according to the vehicle state information and the obstacle distance information, if not, judging whether a controllability constraint condition is met or not, and executing step 3; if yes, judging whether a second switching condition is met, and executing the step 4; step 3, when the controllability constraint is judged to be met, entering a first-stage control method, and calculating front wheel steering angle feedback and rear wheel torque feedback; when the controllability constraint is judged not to be met, entering a second-stage control method, and calculating front wheel steering angle feedback; step 4, when the second switching condition is judged to be met, entering a third-stage control method, and calculating front wheel steering angle feedback; and when the second switching condition is judged not to be met, entering a second stage control method, and calculating front wheel steering angle feedback. Through the technical scheme in the application, the danger avoiding capability of steering collision avoidance auxiliary driving is widened, and the requirement of an emergency steering collision avoidance system on the longitudinal collision avoidance distance is reduced.
The steps in the present application may be sequentially adjusted, combined, and subtracted according to actual requirements.
The units in the device can be merged, divided and deleted according to actual requirements.
Although the present application has been disclosed in detail with reference to the accompanying drawings, it is to be understood that such description is merely illustrative and not restrictive of the application of the present application. The scope of the present application is defined by the appended claims and may include various modifications, adaptations, and equivalents of the invention without departing from the scope and spirit of the application.
Claims (7)
1. An intelligent automobile lane change collision avoidance control method is characterized by comprising the following steps:
step 1, collecting vehicle state information and obstacle distance information;
step 2, judging whether a first switching condition is met or not according to the vehicle state information and the obstacle distance information, if not, judging whether a controllability constraint condition is met or not, and executing step 3; if yes, judging whether a second switching condition is met, and executing the step 4;
step 3, when the controllability constraint is judged to be met, entering a first-stage control method, and calculating front wheel corner feedback and rear wheel torque feedback; when the controllability constraint is judged not to be satisfied, entering a second-stage control method, and calculating the front wheel steering angle feedback;
step 4, when the second switching condition is judged to be met, entering a third-stage control method, and calculating front wheel steering angle feedback; and when the second switching condition is judged not to be met, the control method enters the second stage control method, and the front wheel steering angle feedback is calculated.
2. The intelligent vehicle lane-changing collision-avoidance control method according to claim 1, wherein the obstacle distance information includes a distance from a vehicle center of mass to a left end of the obstacle, a distance from the vehicle center of mass to a right end of the obstacle, and a distance from the vehicle center of mass to an end of the obstacle, the vehicle state information includes at least a vehicle heading angle, in the step 2,
when the collision avoidance is carried out on the left switching track, the first switching condition is as follows: whether the vehicle heading angle phi is larger than or equal to an arc tangent function value of a first distance ratio, wherein the first distance ratio is the ratio of the distance between the center of mass of the vehicle and the tail end of the obstacle to the distance between the center of mass of the vehicle and the left end of the obstacle;
when the right switching lane is in collision avoidance, the first switching condition is as follows: whether the vehicle heading angle phi is smaller than or equal to an arc tangent function value of a second distance ratio, wherein the second distance ratio is the ratio of the distance between the center of mass of the vehicle and the tail end of the obstacle to the distance between the center of mass of the vehicle and the right end of the obstacle.
3. The intelligent vehicle lane-changing collision-avoidance control method according to claim 2, wherein in the step 2, the second switching condition is: the distance from the center of mass of the vehicle to the left end of the obstacle is 0, or,
the distance from the center of mass of the vehicle to the right end of the obstacle is 0.
4. The intelligent automobile lane-changing collision-avoidance control method according to claim 1, wherein the calculation formula of the controllability constraint condition in the step 2 is as follows:
|β front |≤|δ max +α fp |
in the formula, beta front Is the speed direction of the front wheel of the automobile, beta is the centroid slip angle, a is the distance from the centroid of the automobile to the front axle, r is the yaw velocity of the automobile, delta max Maximum front wheel angle, alpha, limited by the steering mechanism fp Is the corresponding tire slip angle at the peak of the tire lateral force.
5. The intelligent automobile lane-changing collision avoidance control method according to claim 1, wherein in the first-stage control method, a calculation formula for calculating the front wheel steering angle feedback is as follows:
in the formula, delta des For front wheel steering angle feedback, V is total vehicle speed, beta is centroid slip angle, a is distance from centroid to front axle, r is vehicle yaw rate, and alpha fp The tire slip angle corresponding to the peak position of the tire lateral force;
the calculation formula for calculating the rear wheel torque feedback is as follows:
τ command ＝RμF zri cos(β+π/2)
in the formula, τ command For rear wheel torque feedback, R is the wheel radius, μ is the road adhesion coefficient, F zri Is the vertical load of a single wheel of the rear wheel.
6. The intelligent automobile lane-changing collision-avoidance control method according to claim 5, wherein in the second-stage control method, a calculation formula for calculating the front wheel steering angle feedback is as follows:
in the formula, delta des Feeding back a front wheel steering angle, wherein V is a total vehicle speed, beta is a centroid sideslip angle, a is a distance from the centroid to a front axle, and r is a vehicle yaw velocity;
in step 3, after entering the second stage control method, the method further includes:
the rear wheel torque feedback is set to 0.
7. The intelligent automobile lane-changing collision-avoidance control method according to claim 1, wherein a calculation formula of a tracking error in the third-stage control method is as follows:
in the formula, Y bou As the left lane boundary，Y ref Is the lane centerline and Y is the current vehicle position Y coordinate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210812001.0A CN115071699A (en) | 2022-07-11 | 2022-07-11 | Intelligent automobile lane changing collision avoidance control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210812001.0A CN115071699A (en) | 2022-07-11 | 2022-07-11 | Intelligent automobile lane changing collision avoidance control method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115071699A true CN115071699A (en) | 2022-09-20 |
Family
ID=83260199
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210812001.0A Pending CN115071699A (en) | 2022-07-11 | 2022-07-11 | Intelligent automobile lane changing collision avoidance control method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115071699A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116729384A (en) * | 2023-06-27 | 2023-09-12 | 广州小鹏自动驾驶科技有限公司 | Detour planning method and device in lane keeping state and vehicle |
-
2022
- 2022-07-11 CN CN202210812001.0A patent/CN115071699A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116729384A (en) * | 2023-06-27 | 2023-09-12 | 广州小鹏自动驾驶科技有限公司 | Detour planning method and device in lane keeping state and vehicle |
| CN116729384B (en) * | 2023-06-27 | 2024-01-09 | 广州小鹏自动驾驶科技有限公司 | Detour planning method and device in lane keeping state and vehicle |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110614998B (en) | Aggressive driving-assisted curve obstacle avoidance and road changing path planning system and method | |
| US8548683B2 (en) | Active steering controller | |
| EP2808228B1 (en) | Lane keeping assist device and lane keeping assist method | |
| Yi et al. | Real time integrated vehicle dynamics control and trajectory planning with MPC for critical maneuvers | |
| US7734416B2 (en) | Automatic vehicle braking device | |
| CN104176054B (en) | A kind of automatic lane change control system of automobile active anti-corrosion and method of work thereof | |
| CN108773376B (en) | Automobile multi-target layered cooperative control and optimization method fusing driving intentions | |
| CN109334564B (en) | Anti-collision automobile active safety early warning system | |
| US20090024278A1 (en) | Steering Control Device for Vehicles | |
| CN110962849B (en) | Curve self-adaptive cruise method | |
| JP5050417B2 (en) | Vehicle steering control device | |
| US20030060955A1 (en) | Method for steering assistance as a function of a driving state | |
| JP7315039B2 (en) | How to find an avoidance route for a car | |
| JP2010076488A (en) | Vehicle | |
| CN115071699A (en) | Intelligent automobile lane changing collision avoidance control method | |
| JP2007038766A (en) | Vehicle steering system | |
| Zhang et al. | Segmented trajectory planning strategy for active collision avoidance system | |
| CN113433942A (en) | Long-axis vehicle path tracking control method based on optimal course angle | |
| CN115534938A (en) | Additional yaw moment-based man-machine co-driving automobile emergency collision avoidance control method and system | |
| CN115489515A (en) | Automatic parking trajectory planning method for narrow vertical parking space and electronic equipment | |
| CN108569288B (en) | definition and collision avoidance control method for dangerous working conditions of automobile | |
| CN113183953B (en) | Active safety control method and system for vehicle after collision based on distributed driving chassis | |
| CN111731380B (en) | Wire-controlled four-wheel steering segmented control method based on tire nonlinear characteristics | |
| US20020032509A1 (en) | Rear-wheel steering angle control device | |
| Rahim et al. | A longitudinal speed controller for autonomous multi-trailer articulated heavy vehicles |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |