CN110614998B - Aggressive driving-assisted curve obstacle avoidance and road changing path planning system and method - Google Patents

Aggressive driving-assisted curve obstacle avoidance and road changing path planning system and method Download PDF

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CN110614998B
CN110614998B CN201910773622.0A CN201910773622A CN110614998B CN 110614998 B CN110614998 B CN 110614998B CN 201910773622 A CN201910773622 A CN 201910773622A CN 110614998 B CN110614998 B CN 110614998B
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speed
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distance
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CN110614998A (en
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吴树凡
魏民祥
任师通
滕德成
贾晟
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Nanjing University of Aeronautics and Astronautics
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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
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/04—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units
    • B60W10/08—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units including control of electric propulsion units, e.g. motors or generators
    • 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
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/18—Conjoint control of vehicle sub-units of different type or different function including control of braking systems
    • 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
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/20—Conjoint control of vehicle sub-units of different type or different function including control of steering systems
    • 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
    • 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
    • B60W30/18—Propelling the vehicle
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    • B60W30/18163—Lane change; Overtaking manoeuvres
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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
    • B60W2710/00—Output or target parameters relating to a particular sub-units
    • B60W2710/20—Steering systems
    • 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
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Abstract

The invention discloses a method for planning an obstacle avoidance and road changing path of an aggressive driving-assisted curve. A curve obstacle avoidance decision method comprises the following steps: firstly, the distance between two vehicles is smaller than the safety distance, secondly, the speed of the front vehicle in the detection range is smaller than the speed limit of the lane by a certain proportion, thirdly, the front vehicle is abnormally braked, and the lane change is carried out when one vehicle is satisfied and no vehicle exists in the lane on the left side of the front vehicle; the path planning method comprises the following steps: and planning and changing the road path by a fifth-order polynomial, and obtaining an optimal path according to an objective function considering the longitudinal distance, the lateral acceleration, the yaw angular velocity and the mass center and lateral deviation angle. The invention avoids unnecessary emergency braking, improves the overall safety and traffic efficiency of traffic, and also meets the pursuit of the driver with aggressive driving style for saving time; and the stability and the lane changing distance are taken as evaluation indexes to plan the lane changing diameter, so that the lane changing stability is ensured.

Description

Aggressive driving-assisted curve obstacle avoidance and road changing path planning system and method
Technical Field
The invention relates to the technical field of assistant driving, in particular to a radical assistant driving curve obstacle avoidance and road diameter changing planning system and method.
Background
With the advent of the artificial intelligence era, intelligent vehicles have become a research hotspot today. The biggest problem of intelligent vehicles on the road is the safety problem, and the active safety technology of automobiles is more and more concerned by people.
According to the difference of the driving behaviors of drivers, the driving behavior can be divided into a cautious type, a normal type and an aggressive type. Researches show that the more aggressive the driving style, the less attention the driver pays to the surrounding environment, the poorer the lateral control stability of the vehicle, and the higher the frequency of lane change, and the aggressive driver often does not meet the requirement of following the front slow vehicle to drive but obtains the speed advantage by frequently changing lanes.
An effective driving assistance obstacle avoidance system needs to have reasonable sensor arrangement, a safe distance model under a specific working condition and an obstacle avoidance strategy which can take stability and instantaneity into consideration. At present, most of researches on emergency obstacle avoidance use an obstacle avoidance method of selecting braking, combination of braking and steering or steering according to the comparison between the distance different from the front vehicle and the safe distance. In the selection of the emergency obstacle avoidance method, when it is detected that no vehicle can pass through the adjacent lane, if the vehicle is stopped and the obstacle is avoided by emergency braking, the vehicle behind may be scared, even a traffic accident may be caused, and the passing efficiency of the vehicle is also reduced.
Therefore, in order to meet the pursuit of the aggressive driver for the speed, when the abnormality in the front of the own vehicle lane is detected, a proper path can be planned in real time under the condition that no obstacle exists in the adjacent lane, and a method for directly steering is selected to avoid the obstacle, so that the traffic efficiency is improved, and the safety is ensured.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to solve the technical problem of providing a radical type auxiliary driving curve obstacle avoidance and road changing path planning system and a radical type auxiliary driving curve obstacle avoidance and road changing path planning system aiming at the defects related in the background technology.
The technical scheme is as follows:
a sharp type curve obstacle avoidance and road diameter changing planning system for assisting driving comprises an environment sensing unit, a self vehicle sensor unit, a CAN bus, an electronic control unit (VCU), a steer-by-wire unit, a brake-by-wire unit and a wheel speed control unit; the environment sensing unit comprises a camera, a laser radar and a millimeter wave radar; the self-vehicle sensor unit comprises a vehicle speed sensor, an acceleration sensor and a front wheel steering angle sensor; the camera is arranged right above a vehicle windshield and used for identifying lane line information, obstacle information and lane speed limit and transmitting image information into the VCU; the laser radars are at least 2 in number (the safety of front-end detection is guaranteed, and the danger caused by the failure of a single radar is prevented), are respectively arranged on a front-end cabin cover and a roof of a vehicle, are used for detecting the relative distance between a front obstacle and the vehicle and the speed and acceleration of the front vehicle, and store information on a CAN bus for a VCU to call and process in real time; the number of the millimeter wave radars is at least 1, the millimeter wave radars are arranged on an air inlet barrier at the front part of the vehicle and are used for detecting the relative distance between a remote vehicle and the vehicle, storing information on a CAN bus and providing real-time calling and processing of a VCU; the vehicle speed sensor, the acceleration sensor and the front wheel steering angle sensor are respectively used for collecting the speed, the longitudinal acceleration and the front wheel steering angle of the vehicle, storing information on the CAN bus and providing real-time calling and processing of the VCU; the steer-by-wire unit comprises a steering power-assisted motor and a steering controller, and is used for receiving a steering signal of the VCU and steering; the brake-by-wire unit comprises a brake wheel cylinder for receiving a brake signal of the VCU and braking; the wheel speed control unit comprises a wheel motor for receiving a wheel speed signal of the VCU and controlling the vehicle speed; the electronic control unit VCU realizes the functions of calculating, judging and sending control signals, and is used for calculating the safety distance between the self vehicle and the front vehicle according to the received speed and longitudinal acceleration of the self vehicle and the speed and acceleration of the front vehicle, and then taking the calculated safety distance as a basis for judging whether to steer; meanwhile, after the current vehicle distance reaches the safe distance, the VCU calculation module calculates and obtains the road changing path and the front wheel rotation angle, the vehicle speed and the longitudinal acceleration required by the road changing, compares the road changing path with the real-time front wheel rotation angle, the real-time vehicle speed and the real-time acceleration of the vehicle, and adjusts the input current of the power steering motor, the pressure of a brake wheel cylinder and the wheel speed according to the difference obtained by comparison, so that the steer-by-wire unit, the brake-by-wire unit and the wheel speed control unit work.
A method for planning an obstacle avoidance and road changing path of an aggressive-type assistant driving curve comprises the following steps:
step 1), a camera collects lane line information, obstacle information and lane speed limit, and the curvature of two lane lines, the obstacle position information and the lane speed limit of a lane where a self-vehicle is located are transmitted to a CAN bus for being called by a VCU for calculation and judgment respectively; the laser radar collects the related information of the front obstacle, and transmits the relative distance between the collected front obstacle and the vehicle and the speed of the front vehicle to the CAN bus, and the relative distance and the speed are respectively used for the VCU to call for judgment and calculation;
step 2), a vehicle speed sensor, an acceleration sensor and a front wheel steering angle sensor respectively collect the vehicle speed, the acceleration and the front wheel steering angle of the vehicle, and input the collected data to a CAN bus and supply an electronic VCU for calculation;
and 3), the VCU establishes a braking safe distance model according to the received speed, the speed and the acceleration of the front vehicle, and calculates the safe distance between the vehicle and the front vehicle according to the Mazda braking safe distance model:
Figure GDA0002741637150000031
wherein, VhIs the speed of the bicycle, vrelIs the relative speed of the front vehicle and the self vehicle, mu is the road surface auxiliary coefficient, g is the gravity acceleration, t1Delay time for driver reaction, t2Delay time for brake, d0The minimum parking distance is obtained, and the calculated safe distance is transmitted to a CAN bus for the VCU to call and judge;
step 4), the VCU judges the distance S between the obstacle in front of the own lane and the own vehiclerealFrom a safe distance SsafeThe difference a, a ═ S is calculatedreal-Ssafe；
Step 5), the camera detects road information, and the speed limit v of the lane is obtained through image recognitionlimThe VCU obtains S by judgingrealAfter a result of ≦ S, S is the distance requiring the measurement operation (S)safeEffective detection distance of sensor，75m as specified by the regulation GBT 20608-2006), and judging the front vehicle speed vqAnd vlimThe value of j1 (j1 ∈ (0,1)), and the difference b, b ═ v, was calculatedq-vlim*j1；
Step 6), the VCU obtains S through judgmentrealAfter the result of S is less than or equal to S, whether the front vehicle is braked emergently is judged (when the front vehicle is braked emergently, the maximum deceleration of the front vehicle is generally 7.5-8 m/S, when the front vehicle is braked ordinarily,the average deceleration of the vehicle should be acom3-4 m/s), the deceleration a of the front vehicle is calculatedqAnd max (a)com) The magnitude, i.e. the calculated difference c is max (a)com)-aq，max(acom) The maximum value of the average deceleration of the automobile during the ordinary braking;
step 7), the camera detects in real time, whether an obstacle exists in a left lane of the front obstacle or not, when one of the difference values a, b and c is less than or equal to 0 and no obstacle exists in the left lane, the VCU calculates a lane changing path to prepare for a decision of directly changing lanes, and when the difference value a, b and c is judged to be false, the pressure of a brake wheel cylinder is calculated to brake;
and 8), the VCU controls the steering wheel rotation angle through the path planning controller, calculates the steering angle delta, the speed v and the brake pedal force F, and transmits the steering angle delta, the speed v and the brake pedal force F to the steer-by-wire unit, the brake-by-wire unit and the speed control unit for control.
Further, j1 is a self-defined speed coefficient determined by j1 in step 5), and since the aggressive driving style driver has the behavior of overtaking from an inner lane due to impatience of a slow-speed driving vehicle on an outer lane, the aggressive driving style driver can be subjected to driving behavior analysis to analyze the ratio of the speed of the front vehicle to the road limit speed during overtaking, and the n data are k1,k2,···knIn order to ensure the accuracy of the data, a least square method is adopted so that
Figure GDA0002741637150000032
At the minimum, the temperature of the mixture is controlled,
Figure GDA0002741637150000033
is an average value, i.e. x when D is minimized,
Figure GDA0002741637150000034
further, in step 7), the method for determining the road change path is as follows:
step 7.1), according to the curvature of the path in the CAN bus, fitting a real-time circular arc curve of the self-vehicle lane by taking the intersection point of the position of the center of the rear wheel of the vehicle and the vertical line of the right lane as an origin (0,0)
Figure GDA0002741637150000041
Wherein R is the curvature radius of the path, and x is the longitudinal distance of the lane change;
setting the lane width as dwThen, the formula of the path where the self vehicle is located is as follows:
Figure GDA0002741637150000042
and 7.2) calculating to obtain a real-time circular arc curve of the road center of the adjacent lane according to the relationship of the road width, namely the target road changing path formula is as follows:
Figure GDA0002741637150000043
7.3) fitting a lane changing path between the circular arc curves at the centers of the two lanes by using the quintic polynomial curve, and planning the lane changing path;
the lane change end target point of the vehicle is (x)s,ys) The road diameter changing equation is set as:
y(x)＝a0+a1x+a2x2+a3x3+a4x4+a5x5
wherein, a0，a1，a2，a3，a4，a5Coefficients of the fifth-order polynomial respectively;
the vehicle is at the initial position x ═ 0 and the end position x ═ x of lane changingsThe following equation is satisfied:
Figure GDA0002741637150000044
wherein Rz is the radius of curvature of the lane line centerline;
solved to obtain a0，a1，a2，a3，a4，a5Assuming that the longitudinal speed V is constant, i.e. xsIf V × t, the lane change trajectory is:
y(x)＝b0+b1t+b2t2+b3t3+b4t4+b5t5
then:
Figure GDA0002741637150000051
Figure GDA0002741637150000052
Figure GDA0002741637150000053
step 7.4), by changing xsNamely, the longitudinal distance is finished by changing the track, and different track changing tracks can be obtained;
step 7.5), assuming that the motion of the vehicle simply obeys ackerman geometry, where the front wheel turning angle is obtained from the basic driver model, the vehicle trajectory curvature is proportional to the steering wheel turning angle:
Figure GDA0002741637150000054
in the formula, L: wheelbase, V: the speed of the machine in the longitudinal direction,
Figure GDA0002741637150000055
for lateral acceleration, deltafIs the corner of the front wheel.
Step 7.6) obtaining an expected front wheel steering angle according to the lateral acceleration obtained by the basic driver model and the secondary derivation of the track under different vehicle speeds, and obtaining a kinematic two-degree-of-freedom model under different track conditions:
Figure GDA0002741637150000056
Figure GDA0002741637150000057
in the formula, K1For total cornering stiffness of the front wheels, K2For total cornering stiffness of the rear wheels, IzIs the moment of inertia around the z axis, m is the total mass of the automobile, a is the distance from the center of mass to the front axis, and b is the distance v from the center of mass to the rear axisyIn order to determine the lateral velocity,
calculating to obtain the yaw angular velocity and the centroid slip angle;
step 7.7) set the objective function as:
Figure GDA0002741637150000061
in the formula: ldFor the longitudinal length l of the track changed＝xd，ay(t), beta (t) and omega (t) are lateral acceleration, yaw angular velocity and mass center slip angle in the lane changing process, aymax、βmax、ωmaxThe maximum lateral acceleration, the maximum yaw angular velocity and the maximum mass center lateral deviation angle, w, in all lane changing tracks1、w2、w3、w4Is a weight coefficient, w1+w2+w3+w4The first item of reaction lane changing efficiency, the second, third and fourth item of reaction lane changing smoothness and safety satisfy an objective function y (t) which is the optimal lane changing track under different vehicle speeds,
has the advantages that:
1) the aggressive obstacle avoidance driving method mainly based on steering lane changing and assisted by braking solves the problem that unnecessary emergency braking causes frightening to drivers behind, improves the overall safety of traffic, solves traffic jam caused by unnecessary braking, and improves traffic passing efficiency;
2) the difference value of the braking deceleration of the front vehicle and the maximum braking deceleration under normal conditions, the difference value of the speed of the front vehicle and the road speed-limiting multiple, and the real-time vehicle distance and the braking safety distance are used as obstacle avoidance triggering conditions, so that the reliability and the driving smoothness of an obstacle avoidance system are improved, and the pursuit of a radical driving style driver for saving time is also met;
3) and (3) planning a lane change path on the premise of stability, comfort evaluation indexes (lateral acceleration, yaw angular velocity and mass center lateral deviation angle) and a longitudinal lane change distance, and ensuring lane change stability and safety.
Drawings
FIG. 1 is a logic block diagram of an aggressive driving-assisted curve obstacle avoidance system;
FIG. 2 is a simplified diagram of a path and vehicle position for a simulated scene;
FIG. 3 is a graph of a fifth-order polynomial transformed road path, corresponding to xsIs 40;
FIG. 4 is a graph of the optimum change road diameter at a curve radius of 650 m.
Detailed Description
The invention is further explained below with reference to the drawings.
As shown in fig. 1, the logic block diagram of the system is divided into 7 parts, namely, an environment sensing unit, a vehicle sensor unit, a CAN bus, a VCU, a steer-by-wire unit, a brake-by-wire unit, and a wheel speed control unit. The following is a detailed explanation of the block diagram flow:
the environment sensing unit comprises a camera, a laser radar and a millimeter wave radar; the self-vehicle sensor unit comprises a vehicle speed sensor, an acceleration sensor and a front wheel steering angle sensor; the camera is arranged right above a vehicle windshield and used for identifying lane line information, obstacle information and lane speed limit and transmitting image information into the VCU; the laser radars are at least 2 in number (the safety of front-end detection is guaranteed, and the danger caused by the failure of a single radar is prevented), are respectively arranged on a front-end cabin cover and a roof of a vehicle, are used for detecting the relative distance between a front obstacle and the vehicle and the speed and acceleration of the front vehicle, and store information on a CAN bus for a VCU to call and process in real time; the number of the millimeter wave radars is at least 1, the millimeter wave radars are arranged on an air inlet barrier at the front part of the vehicle and are used for detecting the relative distance between a remote vehicle and the vehicle, storing information on a CAN bus and providing real-time calling and processing of a VCU; the vehicle speed sensor, the acceleration sensor and the front wheel steering angle sensor are respectively used for collecting the speed, the longitudinal acceleration and the front wheel steering angle of the vehicle, storing information on the CAN bus and providing real-time calling and processing of the VCU; the steer-by-wire unit comprises a steering power-assisted motor and a steering controller, and is used for receiving a steering signal of the VCU and steering; the brake-by-wire unit comprises a brake wheel cylinder for receiving a brake signal of the VCU and braking; the wheel speed control unit comprises a wheel motor for receiving a wheel speed signal of the VCU and controlling the vehicle speed; the electronic control unit VCU realizes the functions of calculating, judging and sending control signals, and is used for calculating the safety distance between the self vehicle and the front vehicle according to the received speed and longitudinal acceleration of the self vehicle and the speed and acceleration of the front vehicle, and then taking the calculated safety distance as a basis for judging whether to steer; meanwhile, after the current vehicle distance reaches the safe distance, the VCU calculation module calculates and obtains the road changing path and the front wheel rotation angle, the vehicle speed and the longitudinal acceleration required by the road changing, compares the road changing path with the real-time front wheel rotation angle, the real-time vehicle speed and the real-time acceleration of the vehicle, and adjusts the input current of the power steering motor, the pressure of a brake wheel cylinder and the wheel speed according to the difference obtained by comparison, so that the steer-by-wire unit, the brake-by-wire unit and the wheel speed control unit work.
The invention also discloses an obstacle avoidance and road changing path planning method based on the obstacle avoidance system, which is characterized by comprising the following steps of:
step 1), a camera collects lane line information, obstacle information and lane speed limit, and the curvature of two lane lines, the obstacle position information and the lane speed limit of a lane where a self-vehicle is located are transmitted to a CAN bus for being called by a VCU for calculation and judgment respectively; the laser radar collects the related information of the front obstacle, and transmits the relative distance between the collected front obstacle and the vehicle and the speed of the front vehicle to the CAN bus, and the relative distance and the speed are respectively used for the VCU to call for judgment and calculation;
step 2), a vehicle speed sensor, an acceleration sensor and a front wheel steering angle sensor respectively collect the vehicle speed, the acceleration and the front wheel steering angle of the vehicle, and input the collected data to a CAN bus and supply an electronic VCU for calculation;
and 3), the VCU establishes a braking safe distance model according to the received speed, the speed and the acceleration of the front vehicle, and calculates the safe distance between the vehicle and the front vehicle according to the Mazda braking safe distance model:
Figure GDA0002741637150000081
wherein, VhIs the speed of the bicycle, vrelIs the relative speed of the front vehicle and the self vehicle, mu is the road surface auxiliary coefficient, g is the gravity acceleration, t1Delay time for driver reaction, t2Delay time for brake, d0The minimum parking distance is obtained, and the calculated safe distance is transmitted to a CAN bus for the VCU to call and judge;
step 4), the VCU judges the distance S between the obstacle in front of the own lane and the own vehiclerealFrom a safe distance SsafeThe difference a, a ═ S is calculatedreal-Ssafe；
Step 5), the camera detects road information, and the speed limit v of the lane is obtained through image recognitionlimThe VCU obtains S by judgingrealAfter a result of ≦ S, S is the distance requiring the measurement operation (S)safeEffective detection distance of sensor，75m as specified by the regulation GBT 20608-2006), and judging the front vehicle speed vqAnd vlimThe value of j1 (j1 ∈ (0,1)), and the difference b, b ═ v, was calculatedq-vlim*j1；
Step 6), the VCU obtains S through judgmentrealAfter the result of S is less than or equal to S, judging whether the front vehicle is braked emergently (the maximum deceleration of the vehicle is generally 7.5-8 m/S in emergency braking, and the average deceleration of the vehicle is a in ordinary brakingcomIs 3-4m/s), the preceding vehicle deceleration a is calculatedqAnd max (a)com) The magnitude, i.e. the calculated difference c is max (a)com)-aq，max(acom) The maximum value of the average deceleration of the automobile during the ordinary braking;
step 7), the camera detects in real time, whether an obstacle exists in a left lane of the front obstacle or not, when one of the difference values a, b and c is less than or equal to 0 and no obstacle exists in the left lane, the VCU calculates a lane changing path to prepare for a decision of directly changing lanes, and when the difference value a, b and c is judged to be false, the pressure of a brake wheel cylinder is calculated to brake;
and 8), the VCU controls the steering wheel rotation angle through the path planning controller, calculates the steering angle delta, the speed v and the brake pedal force F, and transmits the steering angle delta, the speed v and the brake pedal force F to the steer-by-wire unit, the brake-by-wire unit and the speed control unit for control.
Determining j1 in step 5), wherein j1 is a self-defined speed coefficient, and the aggressive driving style driver has the behavior that a slow-speed driving vehicle on an outer lane is impatient and overtaking from an inner lane, so that the aggressive driving style driver can be subjected to driving behavior analysis, the ratio of the front vehicle speed to the road limit speed during overtaking is analyzed, and the n data are k1,k2,···knIn order to ensure the accuracy of the data, a least square method is adopted so that
Figure GDA0002741637150000082
At the minimum, the temperature of the mixture is controlled,
Figure GDA0002741637150000083
is an average value, i.e. when D is minimized
Figure GDA0002741637150000094
The method for determining the road changing path in the step 7) comprises the following steps:
step 7.1), as shown in fig. 2, is a simplified diagram of the path and vehicle position of the simulated scene,
according to the curvature of the path in the CAN bus, a real-time circular arc curve of the self-vehicle lane is fitted by taking the intersection point of the center of the rear wheel of the vehicle and the vertical line of the right lane as the origin (0,0)
Figure GDA0002741637150000091
Wherein R is the curvature radius of the path, and x is the longitudinal distance of the lane change;
setting the lane width as dwThen, the formula of the path where the self vehicle is located is as follows:
Figure GDA0002741637150000092
and 7.2) calculating to obtain a real-time circular arc curve of the road center of the adjacent lane according to the relationship of the road width, namely the target road changing path formula is as follows:
Figure GDA0002741637150000093
y1 is an outer lane center curve, and y2 is an inner lane center curve;
step 7.3), as shown in fig. 3, a lane change path between the circular arc curves at the centers of the two lanes is fitted through a quintic polynomial curve for a vehicle lane change path graph when the lane change distance is set to be 40, and the lane change path is planned;
the lane change end target point of the vehicle is (x)s,ys) The road diameter changing equation is set as:
y(x)＝a0+a1x+a2x2+a3x3+a4x4+a5x5
wherein, a0，a1，a2，a3，a4，a5Coefficients of the fifth-order polynomial respectively;
the vehicle is at the initial position x ═ 0 and the end position x ═ x of lane changingsThe following equation is satisfied:
Figure GDA0002741637150000101
wherein Rz is the radius of curvature of the lane line centerline;
solved to obtain a0，a1，a2，a3，a4，a5Assuming that the longitudinal speed V is constant, i.e. xsIf V × t, the lane change trajectory is:
y(x)＝b0+b1t+b2t2+b3t3+b4t4+b5t5
then:
Figure GDA0002741637150000102
Figure GDA0002741637150000103
Figure GDA0002741637150000104
step 7.4), by changing xsNamely, the longitudinal distance is finished by changing the track, and different track changing tracks can be obtained;
step 7.5), assuming that the motion of the vehicle simply obeys ackerman geometry, where the front wheel turning angle is obtained from the basic driver model, the vehicle trajectory curvature is proportional to the steering wheel turning angle:
Figure GDA0002741637150000111
in the formula, L: wheelbase, V: the speed of the machine in the longitudinal direction,
Figure GDA0002741637150000112
for lateral acceleration, deltafIs the corner of the front wheel.
Step 7.6) obtaining an expected front wheel steering angle according to the lateral acceleration obtained by the basic driver model and the secondary derivation of the track under different vehicle speeds, and obtaining a kinematic two-degree-of-freedom model under different track conditions:
Figure GDA0002741637150000113
Figure GDA0002741637150000114
in the formula, K1For total cornering stiffness of the front wheels, K2For total cornering stiffness of the rear wheels, IzIs the moment of inertia around the z axis, m is the total mass of the automobile, a is the distance from the center of mass to the front axis, and b is the distance v from the center of mass to the rear axisyIn order to determine the lateral velocity,
calculating to obtain the yaw angular velocity and the centroid slip angle;
step 7.7) set the objective function as:
Figure GDA0002741637150000115
in the formula: ldFor the longitudinal length l of the track changed＝xd，ay(t), beta (t) and omega (t) are lateral acceleration, yaw angular velocity and mass center slip angle in the lane changing process, aymax、βmax、ωmaxThe maximum lateral acceleration, the maximum yaw angular velocity and the maximum mass center lateral deviation angle, w, in all lane changing tracks1、w2、w3、w4Is a weight coefficient, w1+w2+w3+w 41, the first item of reaction lane changing efficiency, and the second, third and fourth items of reaction lane changing smoothness and safety;
as shown in FIG. 4, a diagram of a vehicle lane change trajectory and an optimal lane change trajectory with a vehicle speed of 15m/s and a curve radius of 650m, which satisfies an objective function y (t), is an optimal lane change trajectory under different vehicle speeds.
Here w1A value of 0.4, w2The value of the carbon dioxide is 0.2,w3a value of 0.2, w4The value is 0.2.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (2)

1. A method for planning an obstacle avoidance and road changing path of an aggressive-type assistant driving curve is characterized by comprising the following steps:
step 1), a camera collects lane line information, obstacle information and lane speed limit, and the curvature of two lane lines, the obstacle position information and the lane speed limit of a lane where a self-vehicle is located are transmitted to a CAN bus for being called by a VCU for calculation and judgment respectively; the laser radar collects the related information of the front obstacle, and transmits the relative distance between the collected front obstacle and the vehicle and the speed of the front vehicle to the CAN bus, and the relative distance and the speed are respectively used for the VCU to call for judgment and calculation;
step 2), a vehicle speed sensor, an acceleration sensor and a front wheel steering angle sensor respectively collect the vehicle speed, the acceleration and the front wheel steering angle of the vehicle, and input the collected data to a CAN bus and supply an electronic VCU for calculation;
and 3), the VCU establishes a braking safe distance model according to the received speed, the speed and the acceleration of the front vehicle, and calculates the safe distance between the vehicle and the front vehicle according to the Mazda braking safe distance model:
Figure FDA0002741637140000011
wherein, VhIs the speed of the bicycle, vrelIs the relative speed of the front vehicle and the self vehicle, mu is the road surface auxiliary coefficient, g is the gravity acceleration, t1Delay time for driver reaction, t2Delay time for brake, d0For minimum parking distance, and transmitting the calculated safe distance to CAN bus for VCU to enterLine calling and judging;
step 4), the VCU judges the distance S between the obstacle in front of the own lane and the own vehiclerealFrom a safe distance SsafeThe difference a, a ═ S is calculatedreal-Ssafe；
Step 5), the camera detects road information, and the speed limit v of the lane is obtained through image recognitionlimThe VCU obtains S by judgingrealAfter the result is less than or equal to S, S is the distance needing to be measured, and the speed v of the front vehicle is judgedqAnd vlimThe value of j1 (j1 ∈ (0,1)), and the difference b, b ═ v, was calculatedq-vlimJ 1; j1 is a self-defined speed coefficient, since the aggressive driving style driver has the behavior of overtaking from the inner lane due to the impatience of the slow-speed driving vehicle on the outer lane, the aggressive driving style driver can be analyzed for the driving behavior, the ratio of the front vehicle speed to the road limit speed when overtaking is analyzed, and the n data are k1,k2,···knIn order to ensure the accuracy of the data, a least square method is adopted so that
Figure FDA0002741637140000012
At the minimum, the temperature of the mixture is controlled,
Figure FDA0002741637140000013
is an average value, i.e. x when D is minimized,
Figure FDA0002741637140000014
step 6), the VCU obtains S through judgmentrealAfter the result of S or less, calculating the deceleration a of the front vehicle by judging whether the front vehicle brakes emergentlyqAnd max (a)com) The magnitude, i.e. the calculated difference c is max (a)com)-aq，max(acom) The maximum value of the average deceleration of the automobile during the ordinary braking;
step 7), the camera detects in real time, whether an obstacle exists in a left lane of the front obstacle or not, when one of the difference values a, b and c is less than or equal to 0 and no obstacle exists in the left lane, the VCU calculates a lane changing path to prepare for a decision of directly changing lanes, and when the difference value a, b and c is judged to be false, the pressure of a brake wheel cylinder is calculated to brake;
and 8), the VCU controls the steering wheel rotation angle through the path planning controller, calculates the steering angle delta, the speed v and the brake pedal force F, and transmits the steering angle delta, the speed v and the brake pedal force F to the steer-by-wire unit, the brake-by-wire unit and the speed control unit for control.
2. The planning method for avoiding obstacles and changing road paths of an aggressive driving-assisted curve according to claim 1, wherein in the step 7), the method for determining the road-changing path comprises the following steps:
step 7.1), according to the curvature of the path in the CAN bus, fitting a real-time circular arc curve of the self-vehicle lane by taking the intersection point of the position of the center of the rear wheel of the vehicle and the vertical line of the right lane as an origin (0,0)
Figure FDA0002741637140000021
Wherein R is the curvature radius of the path, and x is the longitudinal distance of the lane change;
setting the lane width as dwThen, the formula of the path where the self vehicle is located is as follows:
Figure FDA0002741637140000022
and 7.2) calculating to obtain a real-time circular arc curve of the road center of the adjacent lane according to the relationship of the road width, namely the target road changing path formula is as follows:
Figure FDA0002741637140000023
7.3) fitting a lane changing path between the circular arc curves at the centers of the two lanes by using the quintic polynomial curve, and planning the lane changing path;
the lane change end target point of the vehicle is (x)s,ys) The road diameter changing equation is set as:
y(x)＝a0+a1x+a2x2+a3x3+a4x4+a5x5
wherein, a0，a1，a2，a3，a4，a5Coefficients of the fifth-order polynomial respectively;
the vehicle is at the initial position x ═ 0 and the end position x ═ x of lane changingsThe following equation is satisfied:
Figure FDA0002741637140000031
wherein Rz is the radius of curvature of the lane line centerline;
solved to obtain a0，a1，a2，a3，a4，a5Assuming that the longitudinal speed V is constant, i.e. xsIf V × t, the lane change trajectory is:
y(x)＝b0+b1t+b2t2+b3t3+b4t4+b5t5
then:
Figure FDA0002741637140000032
Figure FDA0002741637140000033
C＝[V3 V4 V5]
Figure FDA0002741637140000034
step 7.4), by changing xsNamely, the longitudinal distance is finished by changing the track, and different track changing tracks can be obtained;
step 7.5), the front wheel turning angle is obtained by a basic driver model:
Figure FDA0002741637140000035
in the formula, L: wheelbase, V: the speed of the machine in the longitudinal direction,
Figure FDA0002741637140000041
for lateral acceleration, deltafIs a front wheel corner;
step 7.6) obtaining an expected front wheel steering angle according to the lateral acceleration obtained by the basic driver model and the secondary derivation of the track under different vehicle speeds, and obtaining a kinematic two-degree-of-freedom model under different track conditions:
Figure FDA0002741637140000042
Figure FDA0002741637140000043
in the formula, K1For total cornering stiffness of the front wheels, K2For total cornering stiffness of the rear wheels, IzIs the moment of inertia around the z axis, m is the total mass of the automobile, a is the distance from the center of mass to the front axis, and b is the distance v from the center of mass to the rear axisyIs the lateral velocity;
calculating to obtain the yaw angular velocity and the centroid slip angle;
step 7.7) set the objective function as:
Figure FDA0002741637140000044
in the formula: ldFor the longitudinal length l of the track changed＝xd，ay(t), beta (t) and omega (t) are lateral acceleration, yaw angular velocity and mass center slip angle in the lane changing process, aymax、βmax、ωmaxThe maximum lateral acceleration, the maximum yaw angular velocity and the maximum mass center lateral deviation angle, w, in all lane changing tracks1、w2、w3、w4Is a weight coefficient, w1+w2+w3+w4The first term of the reaction lane changing efficiency, the second, third and fourth term of the reaction lane changing smoothness and safety satisfy the objective function y (t), namely the optimal lane changing track under different vehicle speeds.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11567506B2 (en) * 2019-12-30 2023-01-31 Baidu Usa Llc Speed planning guidance line for mild slow down
CN111081069B (en) * 2019-12-31 2021-08-06 交通运输部公路科学研究所 Vehicle track control method for bottleneck area of expressway
CN111216718B (en) * 2020-01-10 2022-04-08 浙江吉利汽车研究院有限公司 Collision avoidance method, device and equipment
CN111443709B (en) * 2020-03-09 2023-08-29 北京百度网讯科技有限公司 Vehicle road line planning method, device, terminal and storage medium
CN111488674B (en) * 2020-03-12 2024-01-16 上海理工大学 Plane intersection vehicle running track simulation method
CN111649955B (en) * 2020-04-28 2022-03-11 东南大学 Performance evaluation method for vehicle-road cooperative automatic emergency braking system
CN111413990A (en) * 2020-05-07 2020-07-14 吉林大学 Lane change track planning system
CN111731282B (en) * 2020-06-04 2023-05-23 南京航空航天大学 Emergency collision avoidance system considering vehicle stability and control method thereof
CN113954834A (en) * 2020-07-15 2022-01-21 荷兰移动驱动器公司 Lane changing planning method and vehicle-mounted device
CN111873990A (en) * 2020-07-15 2020-11-03 哈尔滨理工大学 Lane changing collision avoidance device and method suitable for high-speed emergency working condition
CN112100565B (en) * 2020-08-31 2022-09-06 中国第一汽车股份有限公司 Road curvature determination method, device, equipment and storage medium
CN112265548B (en) * 2020-09-15 2022-06-14 北京工业大学 Automatic driving control strategy adjustment method considering road surface condition
CN112238856B (en) * 2020-10-13 2022-04-05 南京航空航天大学 Intelligent vehicle overtaking track optimization method based on hybrid particle swarm optimization
CN112068574A (en) * 2020-10-19 2020-12-11 中国科学技术大学 Control method and system for unmanned vehicle in dynamic complex environment
CN112455444B (en) * 2020-11-26 2021-12-07 东风汽车集团有限公司 Lane changing device and method for autonomously learning lane changing style of driver
CN112677963B (en) * 2021-01-07 2022-02-15 吉林大学 Intelligent networking four-wheel independent steering and independent driving electric automobile emergency obstacle avoidance system
CN112918443B (en) * 2021-03-09 2022-07-12 一汽解放汽车有限公司 Brake control method, device, equipment and storage medium
CN113525365A (en) * 2021-07-21 2021-10-22 上汽通用五菱汽车股份有限公司 Road planning method, device and computer readable storage medium
CN114030474B (en) * 2021-08-19 2022-08-12 东南大学 Driving safety field construction method based on driver subjective risk experience
CN114371691B (en) * 2021-10-26 2024-04-16 南京航空航天大学 Tracking control method for auxiliary driving curve track
CN114407880B (en) * 2022-02-18 2023-06-27 岚图汽车科技有限公司 Unmanned emergency obstacle avoidance path tracking method
CN116834729B (en) * 2023-08-28 2023-11-17 常州星宇车灯股份有限公司 Transverse and longitudinal combined control system and control method for vehicle auxiliary driving

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007040539B4 (en) * 2006-09-04 2014-03-27 Denso Corporation Vehicle control system
CN105109486B (en) * 2015-09-18 2018-02-23 智车优行科技（北京）有限公司 Vehicle safety monitors and control device and method
JP6447962B2 (en) * 2016-12-05 2019-01-09 マツダ株式会社 Vehicle control device
CN106965808A (en) * 2017-04-17 2017-07-21 南京航空航天大学 Automobile transverse and longitudinal active negotiation anti-collision system and its coordination approach
CN206781743U (en) * 2017-04-24 2017-12-22 南京航空航天大学 Automobile differential steering system with a variety of collision avoidance patterns
CN108569288B (en) * 2018-04-12 2019-12-06 南京航空航天大学 definition and collision avoidance control method for dangerous working conditions of automobile

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