CN114312765B - Longitudinal active anti-collision control system and method - Google Patents
Longitudinal active anti-collision control system and method Download PDFInfo
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Abstract
The invention discloses a longitudinal active anti-collision control system and a method, and the longitudinal active anti-collision control system comprises an environment and obstacle detection system, a chassis anti-collision control system, a wheel independent drive-by-wire system and a wheel independent drive-by-wire brake system, wherein the chassis anti-collision control system comprises a front-end collision protection system and a rear-end collision protection system; the wheel independent brake-by-wire system comprises a vehicle body stabilizing module and a brake delay compensation module, wherein the vehicle body stabilizing module is used for ensuring the stability of a vehicle, and the brake delay compensation module is used for compensating brake delay caused by brake execution action delay and communication delay. The system completes independent braking and independent driving operation commands of the independent wheels by using corresponding control strategies according to the external environment and the obstacle information, and guarantees the stability and safety of the vehicle in the running process.
Description
Technical Field
The invention relates to a longitudinal active anti-collision control system and a longitudinal active anti-collision control method.
Background
With the rapid development of science and technology, the logistics transportation industry also develops towards the direction of intellectualization and networking, and under the intelligent wave tide of the automobile industry, the improvement and the development of the wire control chassis of the whole automobile show a rapid growth trend. Along with the increasing annual output of automobiles, the social problems caused by the automobile are also becoming more serious, the problems of large energy consumption, traffic jam, high casualty rate of vehicle traffic accidents, environmental pollution and the like are mainly involved, wherein the occurrence of the traffic accidents causes huge damage to the life and property safety of people, the wire control chassis is the basis of various intelligent transformation and intelligent operation of the current vehicles, and the improvement and further research on the wire control chassis become great tendency under the combined action of policies and markets.
Compared with the traditional chassis, the drive-by-wire chassis eliminates the error of partial actuators, and provides possibility for unmanned driving. The control of the drive-by-wire chassis is mainly based on the drive-by-wire braking, the drive-by-wire steering and the drive-by-wire of the vehicle chassis, most of rear-end collision accidents occur in the longitudinal running, and the design of an active anti-collision control drive-by-wire chassis aiming at the rear-end collision when the longitudinal vehicle runs becomes necessary.
Disclosure of Invention
In order to solve the problems, the invention provides a longitudinal active anti-collision control system and a longitudinal active anti-collision control method.
In order to achieve the technical purpose and achieve the technical effect, the invention is realized by the following technical scheme:
a longitudinal active anti-collision control system comprises an environment and obstacle detection system, a chassis anti-collision control system, a wheel independent line-control driving system and a wheel independent line-control braking system, wherein the environment and obstacle detection system is used for detecting and acquiring environment information and obstacle position and motion state information of front, rear, left and right sides of a vehicle; the independent wheel wire control brake system comprises a vehicle body stabilizing module and a brake delay compensation module, wherein the vehicle body stabilizing module is used for ensuring the stability of a vehicle, and the brake delay compensation module is used for compensating brake delay caused by brake execution action delay and communication delay.
Preferably, still include car communication system and high in the clouds communication system: the vehicle-vehicle communication system is used for information interaction between vehicles of a line-control chassis vehicle type and information interaction between the vehicles of the line-control chassis vehicle type and other vehicle types; the cloud communication system is used for recording the environment of the line-control chassis vehicle type vehicle and the environment information data collected by the obstacle detection system, transmitting the environment information data to the non-line-control chassis vehicle type vehicle, and simultaneously feeding back the information record of the non-line-control chassis vehicle type vehicle to the line-control chassis vehicle type vehicle to complete all information interaction of the road vehicle; the cloud communication system further comprises an information integration unit A, and the information integration unit A integrates information of information received by the cloud communication system, obstacle information detected by the environment and obstacle detection system, and interaction information of the vehicle-vehicle communication system.
Preferably, the environment and obstacle detection system comprises an intelligent look-around sensor system, a wheel center relative height measuring instrument, an information integration unit B and a flatness information correction unit:
the intelligent all-round looking sensor system comprises a mechanical laser radar at the top of the vehicle head, a solid laser radar at the front part of the vehicle head, a binocular camera at the intersection of the top of the vehicle head and the front part and a monocular camera at the tail part of the vehicle;
the information integration unit B integrates information acquired by the mechanical laser radar and the binocular camera with vehicle interaction information acquired by a vehicle-vehicle communication system and a cloud communication system, so that the states of obstacles and surrounding vehicles are accurate;
and the flatness information correction unit corrects the flatness information of the road around the vehicle running, which is acquired by the solid-state laser radar and the wheel center relative height measuring instrument.
Preferably, the chassis collision avoidance control system is used for controlling a three-axis six-wheel vehicle, the wheel independent drive-by-wire system is a six-wheel independent drive-by-wire system, the six wheels are all driving wheels, and each driving wheel comprises three working modes, namely a driving mode, a follow-up mode and an emptying mode;
the independent brake-by-wire system for the wheels is a six-wheel independent brake-by-wire system, and the vehicle body stabilizing module and the brake delay compensation module are used for ensuring the self stability and non-delay braking of the vehicle during braking.
Preferably, driving wheels of a first shaft at the front end of the vehicle and a third shaft at the tail end of the vehicle adopt a wheel edge driving mode, driving wheels of a second shaft in the middle of the vehicle adopt a hub motor driving mode, the first shaft at the front end of the vehicle and the third shaft at the tail end of the vehicle adopt electro-hydraulic coupling braking, and the second shaft in the middle of the vehicle adopts electromechanical braking.
Preferably, when the second shaft is in the emptying mode and only the wheels of the first shaft and the third shaft are braked and operated, the wheel cylinder pressure values of the brakes of the four wheels of the first shaft and the third shaft are respectively as follows:
in the formula, p 1 、p 2 、p 5 、p 6 The braking pressures of the left and right wheels of the first shaft and the left and right wheels of the third shaft are respectively expressed in MPa; f Z1 、F Z2 、F Z5 、F Z6 The unit of the vertical ground acting force is N, and the vertical ground acting force is respectively the left and right wheels of the first shaft and the left and right wheels of the third shaft; r is w1 、R w3 The radius of the wheels on the first shaft and the third shaft is respectively, and the unit is meter; k b Of braking pressure coefficient, of magnitude of wheel braking torque and wheel cylinder pressureA ratio; Δ M Z The desired yaw moment for the vehicle in Nm; b is 1 The distance from the center of the left and right wheels of the first shaft to the shaft center, B 3 The distance from the center of the left and right wheels of the third shaft to the axle center is meter; delta 1 、δ 2 、δ 5 、δ 6 The rotation angles of the left and right wheels of the first shaft and the left and right wheels of the third shaft are respectively expressed in rad.
Preferably, the compensation wheel cylinder pressure value of the braking delay compensation module is as follows:
in the formula, p com To compensate for wheel cylinder pressure value, t 1 For communication delay time, t 2 ' time taken for brake clearance reduction, t 2 "time taken for the brake to gradually compress to stabilize, t after the brake starts to act 1 +t 2 ’+t 2 In the "/2 time period, p pro The value is 30-80% of the maximum wheel cylinder pressure value, and the unit is MPa, p pro The value of (b) depends on the braking deceleration value in the chassis collision avoidance control system, and p (t) is the pressure value of the brake wheel cylinder at the time t and has the unit of MPa.
Preferably, the correction formula of the flatness information correction unit is:
in the formula, h n,i The relative height of the ith rough road surface low obstacle around the corrected vehicle is obtained; h' n,i And h' n,i The relative height of the i-th rough road around the vehicle, which is measured by the solid laser radar detection and the wheel center relative height measuring instrument, is measured in meters; v. of x Is the longitudinal speed of the vehicle, and the unit is m/s; k is a radical of vx And the unit is m/s, which is a longitudinal vehicle speed influence factor.
Preferably, the obstacle information after information integration by the information integration unit B is:
in the formula, x cj 、y cj 、v cj 、a cj Respectively acquiring the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the jth dynamic barrier around the vehicle by using the binocular camera; x is a radical of a fluorine atom dj 、y dj 、v dj 、a dj Respectively acquiring the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the jth dynamic obstacle around the vehicle by the mechanical laser radar; x is a radical of a fluorine atom wi 、y wi 、v wi 、a wi Respectively detecting the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the ith chassis-by-wire vehicle type vehicle detected by a vehicle-to-vehicle communication system; x is the number of i 、y i 、v i 、a i Respectively the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the integrated ith line-controlled chassis vehicle type vehicle; x is the number of n-i 、y n-i 、v n-i 、a n-i The method comprises the steps of integrating longitudinal instantaneous position, transverse instantaneous position, instantaneous speed and instantaneous acceleration of a vehicle of a non-linear control chassis vehicle type, wherein n is the number of dynamic obstacles detected by a mechanical laser radar, and j = 1\8230n; k is a radical of w The interactive information accuracy coefficient; k is a radical of formula d The accuracy coefficient of radar information; k is a radical of c Is a coefficient of accuracy of the camera information,k w 、k d and k c All the values of (A) are positive numbers smaller than 1; x is the number of d，n-i 、y d，n-i 、v d，n-i 、a d，n-i Respectively acquiring the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the nth-i dynamic obstacles around the vehicle by the mechanical laser radar; x is the number of c，n-i 、y c，n-i 、v c，n-i 、a c，n-i The longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the nth-i dynamic obstacles around the vehicle are acquired by the binocular camera respectively.
Correspondingly, the chassis collision avoidance control system comprises a collision avoidance mode with a communication function and a collision avoidance mode without the communication function:
anticollision mode with communication function: judging the collision risk of the self-vehicle according to the obstacle information data integrated by the environment and obstacle detection system, the vehicle-vehicle communication system and the cloud communication system, and deciding the execution actions of all systems of the wire control chassis by using the obstacle data and a corresponding control strategy to avoid collision with a dynamic and static obstacle;
the collision avoidance method comprises the following steps of judging the collision risk of a self-vehicle only according to the environment and dynamic and static obstacle information collected by an obstacle detection system, deciding the execution actions of all systems of a wire control chassis by using obstacle data and a corresponding control strategy, and avoiding collision with the dynamic and static obstacles, wherein the specific algorithm is as follows:
a) And setting the longitudinal distance d (t) between two adjacent vehicles at the time t as follows:
d(t)＝x f (t) -x (t) or d (t) = x (t) -x r (t)
In the formula, x f (t) is the longitudinal position of the front vehicle of the line-control chassis vehicle type at the time t, x (t) is the longitudinal position of the line-control chassis vehicle type at the time t, x r (t) is the longitudinal position of the rear vehicle of the line control chassis vehicle type at the time t, and the unit is meter;
b) the calculation formula of the longitudinal driving force or the longitudinal braking force controlled by the chassis collision avoidance control system at the time t is as follows:
in the formula, F (t) is longitudinal driving force or braking force of the vehicle at the time t, and the unit is N; m is the total vehicle mass of the self vehicle; q and k are integral sliding mode coefficients; lambda [ alpha ] 1 In order to improve the headway coefficient; f a (t)、F r (t) air resistance and rolling resistance at time t, respectively, in units of N;
a first derivative of the longitudinal position error value of the adjacent vehicle at the time t;
a second derivative of the error value of the longitudinal position of the adjacent vehicle at the time t; a is des (t) obtaining the expected acceleration of the self-vehicle by a sliding mode control strategy at the time t; v. of 1 And v 2 Respectively the longitudinal speed of the front vehicle and the longitudinal speed of the rear vehicle in two adjacent vehicles, and the unit is m/s;
in the formula, lambda is an integral sliding mode coefficient and is dimensionless, e (t) is the longitudinal position error value of two adjacent vehicles at the time t, and the unit is m; s is i Is a slip form surface, G is a normal number;
c) The protection front end collision system judges the risk of collision between the head of the self vehicle and the front vehicle, and when the difference between the longitudinal position of the vehicle closest to the front of the self vehicle and the longitudinal position of the self vehicle is smaller than the expected distance, the protection front end collision system is started, wherein the calculation formula of the longitudinal expected distance between the self vehicle and the front vehicle is as follows:
in the formula, d x,des The expected distance between the self vehicle and the front vehicle; v. of x The longitudinal speed of the vehicle is the self longitudinal speed; v. of x,f The longitudinal speed of the front vehicle; a is x Is the self-vehicle longitudinal acceleration; a is a x,f Longitudinal acceleration of the front vehicle; lambda [ alpha ] 1 In order to improve the headway coefficient; lambda [ alpha ] 2 Is a speed proportionality coefficient; lambda [ alpha ] 3 Is the acceleration difference coefficient; d is the minimum driving distance of the vehicle and the unit is m;
starting a front-end collision protection system, wherein a braking force distribution formula is as follows:
F 1,bra ＝0.4F bra
in the formula, F 1,bra 、F 2,bra 、F 3,bra Braking forces distributed to wheels of the first shaft, the second shaft and the third shaft respectively; a is bra Is the braking deceleration; f bra Is the braking force;
d) The rear-end collision protection system judges the risk of collision between the tail of the bicycle and the rear bicycle, when the longitudinal distance between the bicycle and the rear bicycle is smaller than the expected distance and the front vehicle, the barrier or the front vehicle barrier is not threatened, the rear-end collision protection system is started, the bicycle is in an acceleration state, and the longitudinal expected distance calculation formula between the bicycle and the rear bicycle is as follows:
in the formula，d x,des’ The expected distance between the self vehicle and the front vehicle; v. of x The longitudinal speed of the bicycle; v. of x,r The longitudinal speed of the rear vehicle; a is a x Is the longitudinal acceleration of the bicycle; a is x,r Longitudinal acceleration of the rear vehicle; lambda 1 For improving headway factor, λ 2 Is a speed proportionality coefficient, λ 3 D is the minimum driving distance of the vehicle and the unit is m;
starting a rear-end collision protection system, wherein the driving force distribution formula is as follows:
F acc,1 ＝0.3F acc
in the formula, F acc,1 、F acc,2 、F acc,3 Driving forces distributed to the wheels of the first shaft, the second shaft and the third shaft respectively; a is a acc Is the acceleration; f acc Is a driving force;
e) When two adjacent vehicles are wire-controlled chassis vehicle type vehicles, if the actual longitudinal distance between the two vehicles is smaller than the expected longitudinal distance between the two vehicles, the protection rear-end collision system of the front vehicle and the protection front-end collision system of the rear vehicle work simultaneously, the front vehicle is in an acceleration state, the rear vehicle is in a deceleration state, and the front vehicle and the rear vehicle start the protection collision systems simultaneously.
The beneficial effects of the invention are:
1. the six-wheel independent drive-by-wire system and the six-wheel independent brake-by-wire system in the system can enable the drive-by-wire chassis to more finely and accurately distribute the braking force and the driving force of each wheel, so that the driving force and the braking force of each wheel can be independently controlled when the vehicle meets the road surfaces with different road surface adhesion conditions, and the vehicle with the drive-by-wire chassis can stably, safely and reliably run on the complex road surfaces.
2. The line-control chassis anti-collision control system of the system is closely transmitted with the intelligent look-around sensor system and the communication system, so that the external driving environment information and the surrounding obstacle information can be accurately obtained, and the line-control chassis anti-collision control system is rapid, timely and effective in control operation.
3. The active anti-collision control of the system is divided into two types, one type is to protect front-end collision and complete active anti-collision through the braking operation of a rear vehicle; the other type is to protect the rear end collision, and the front vehicle is accelerated to complete active collision avoidance. Simultaneously, when the front vehicle and the rear vehicle are all carried with the drive-by-wire chassis anti-collision control system, the front vehicle and the rear vehicle can simultaneously start the front-end collision protection and the rear-end collision protection, so that the active anti-collision operation is quicker, and the anti-collision operation in a shorter time is realized.
4. The system compensates the brake delay in the brake system, so that the brake delay phenomenon is not shown to the outside, and the brake effect finally obtained is that no brake delay exists.
Drawings
FIG. 1 is a schematic diagram of a longitudinal active crash control system according to the present invention;
fig. 2 is a schematic flow chart of a longitudinal active collision avoidance control method according to the present invention.
Detailed Description
The present invention will be better understood and implemented by those skilled in the art by the following detailed description of the technical solution of the present invention with reference to the accompanying drawings and specific examples, which are not intended to limit the present invention.
As shown in fig. 1-2, a longitudinal active collision avoidance control system includes an environment and obstacle detection system for detecting and collecting environment information and obstacle position and motion state information of each of the front, rear, left, and right sides of a vehicle. The longitudinal active anti-collision control system further comprises a chassis anti-collision control system, a wheel independent drive-by-wire system and a wheel independent drive-by-wire system, the chassis anti-collision control system comprises a front-end collision protection system and a rear-end collision protection system, the wheel independent drive-by-wire system is used for applying independent driving force to each wheel of the vehicle, and the wheel independent drive-by-wire system is used for applying independent braking force to each wheel of the vehicle.
The chassis anti-collision control system is divided into a front-end collision protection system and a rear-end collision protection system, and realizes the longitudinal anti-collision of a line-controlled chassis vehicle type vehicle through the combined action of the line-controlled drive, the line-controlled brake, the steering and the suspension and an anti-collision control strategy.
The chassis anti-collision control system controls the braking force and the driving force of each wheel according to the information collected by the environment and obstacle detection system, so that the vehicle can realize front end collision protection and rear end collision protection; the independent wheel wire control brake system comprises a vehicle body stabilizing module and a brake delay compensation module, wherein the vehicle body stabilizing module is used for ensuring the stability of a vehicle, and the brake delay compensation module is used for compensating brake delay caused by brake execution action delay and communication delay.
In order to improve driving safety and crashproof reliability, the intelligence of whole road, preferably, vertical initiative anticollision control system still includes car communication system and high in the clouds communication system: the vehicle-vehicle communication system is used for information interaction between vehicles of a line-control chassis vehicle type and information interaction between the vehicles of the line-control chassis vehicle type and other vehicle types; the cloud communication system is used for recording the environment of the vehicle of the wire-controlled chassis vehicle type and the environment information data collected by the obstacle detection system, transmitting the environment information data to the vehicle of the non-wire-controlled chassis vehicle type, and simultaneously feeding the information record of the vehicle of the non-wire-controlled chassis vehicle type back to the vehicle of the wire-controlled chassis vehicle type to complete all information interaction of the road vehicle; the cloud communication system further comprises an information integration unit A, and the information integration unit A integrates information of information received by the cloud communication system, obstacle information detected by the environment and obstacle detection system, and interaction information of the vehicle-vehicle communication system.
Generally, the environment and obstacle detection system includes an intelligent look-around sensor system, a wheel center relative height measuring instrument, an information integration unit B, and a flatness information correction unit:
the intelligent all-round-looking sensor system comprises a mechanical laser radar at the top of the vehicle head, a solid laser radar at the lower part of the front part of the vehicle head, a binocular camera at the intersection of the top and the front part of the vehicle head and a monocular camera at the tail part of the vehicle.
Environment and obstacle detecting system contain two different types of laser radar, carry on different types of radar in the different positions of vehicle, for example, can install a solid-state laser radar in the anterior bumper top of locomotive, its solid-state laser radar's lower bottom surface apart from locomotive bumper top h bum At a centimeter point. The solid-state laser radar is used for detecting the position and shape information of raised ground, sunken ground and low obstacles, and the relative height of the ith rough road low obstacle around the vehicle collected by the solid-state laser radar is h' n,i Including raised, recessed and low obstacles, h' n,i Taking positive and negative values in meters. When the height of the obstacle is lower than h n0 When the distance is cm, the solid laser radar judges that the obstacle is a short obstacle, and other high obstacles are obstacles needing to avoid collision and cannot directly cross.
Can be arranged above the vehicle head and away from the vehicle head back surface h rear A 32-line mechanical laser radar is arranged at a centimeter position and is arranged at a height h fixed on the head of the vehicle hig A centimeter fixed support. The mechanical laser radar is used for detecting the position information of obstacles in front of and on the left and right sides of the vehicle, and the vehicle internal calculation unit calculates the position and motion state information of surrounding obstacles or other vehicles by receiving the position information of the obstacles in real time, wherein the obstacle information is the information of moving obstacles and static obstacles, x dj 、y dj 、v dj 、a dj Respectively acquiring the longitudinal instantaneous position, the transverse instantaneous position (in m), the instantaneous speed (in m/s) and the instantaneous acceleration (m/s) of the jth dynamic obstacle around the vehicle by the mechanical laser radar 2 )，x sk Longitudinal position, y, of the kth static obstacle around the vehicle, collected for a mechanical lidar sk The lateral position of the kth static obstacle around the vehicle, as collected by the mechanical lidar, is in units of m.
The environment and obstacle detection system comprises two binocular cameras and one monocular camera, wherein the binocular cameras are arranged in the front of the vehicle head and have a vertical distance h from the top of the vehicle head top The monocular camera is arranged at the middle position of the centimeter position and at the middle position of the tail part of the vehicle chassis. Binocular camera is used for detecting the obstacle position information in the front of the vehicle and the left and right sides of the vehicle, and is used for assisting the mechanical laser radar in ranging in daytime and when the outdoor light brightness meets the corresponding conditions, x cj 、y cj 、v cj 、a cj The instantaneous position, the instantaneous speed and the instantaneous acceleration of the jth dynamic barrier around the vehicle are acquired by the binocular camera respectively. The monocular camera is used for detecting the position information of other vehicles at the rear part of the vehicle relative to the vehicle, and the position and motion state information of the rear vehicle are calculated by the vehicle internal calculation unit through receiving the position information of the obstacle in real time.
The above-mentioned installation distance h bum 、h rear 、h hig 、h top The size of the vehicle is determined by the specific vehicle type and the size of the whole vehicle.
And the information integration unit B integrates information acquired by the mechanical laser radar and the binocular camera with vehicle interaction information acquired by a vehicle-vehicle communication system and a cloud communication system, so that the states of obstacles and surrounding vehicles are accurate. The information integration unit B compares, corrects and fuses the information in the vehicle interior calculation unit to obtain the final obstacle and other vehicle information, and preferably, the obstacle information after the information integration by the information integration unit B is:
in the formula, x cj 、y cj 、v cj 、a cj The longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the jth dynamic barrier around the vehicle are acquired by the binocular camera respectively; x is the number of dj 、y dj 、v dj 、a dj Respectively acquiring the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the jth dynamic obstacle around the vehicle by the mechanical laser radar; x is the number of wi 、y wi 、v wi 、a wi Respectively detecting the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the ith chassis-by-wire vehicle type vehicle detected by a vehicle-to-vehicle communication system; x is the number of i 、y i 、v i 、a i Respectively the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the integrated ith line-controlled chassis vehicle type vehicle; x is the number of n-i 、y n-i 、v n-i 、a n-i The method is characterized in that the method comprises the steps of integrating the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of a non-wire control chassis vehicle type vehicle, wherein n is the number of dynamic obstacles detected by a mechanical laser radar, and j =1 \ 8230n; k is a radical of w The interactive information accuracy coefficient; k is a radical of d The accuracy coefficient of radar information; k is a radical of c Is a camera information accuracy coefficient, k w 、k d And k c All the values of (A) are positive numbers smaller than 1; x is the number of d，n-i 、y d，n-i 、v d，n-i 、a d，n-i Respectively acquiring the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous moment of the n-i dynamic obstacles around the vehicle by the mechanical laser radarAcceleration of time; x is a radical of a fluorine atom c，n-i 、y c，n-i 、v c，n-i 、a c，n-i The longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the nth-i dynamic obstacles around the vehicle are acquired by the binocular camera respectively.
k w 、k d 、k c All are non-negative numbers smaller than 1, the calculation method in the formula is proportional weight calculation, and the accuracy coefficient of the camera information is influenced by the illumination intensity of natural light:
Eav＞30000lx,k c ＝0.8
5000lx＜Eav≤30000lx,k c ＝0.7
100lx＜Eav≤5000lx,k c ＝0.5
Eav≤100lx,k c ＝0
when the illumination intensity is more than 3 million lux under the driving environment, k c The value is 0.8; when the illumination intensity is more than 5000 lux and less than 3 kilo-lux under the driving environment, k c The value is 0.7; when the illumination intensity is more than 100 lux and less than 5000 lux under the driving environment, k c The value is 0.5; when the illumination intensity is less than 100 lux under the driving environment, k c The value is 0.
And the flatness information correction unit corrects the flatness information of the road around the vehicle running, which is acquired by the solid-state laser radar and the wheel center relative height measuring instrument. A flatness information correction unit for comparing and correcting the road surface flatness information of the road surface on which the first axle wheel passes, measured by the wheel center relative height measuring instrument, with the information detected by the solid state laser radar, preferably, the correction formula of the flatness information correction unit is as follows:
in the formula, h n,i The relative height of the ith rough road low obstacle around the corrected vehicle comprises a bulge, a recess and a low obstacle; h' n,i And h' n,i Respectively solid state lidar detection and wheel center phaseMeasuring the relative height of the ith rough road surface low obstacle around the vehicle by a height measuring instrument, wherein the unit is meter; v. of x Is the longitudinal speed of the vehicle, and the unit is m/s; k is a radical of formula vx And the unit is m/s, which is a longitudinal vehicle speed influence factor.
The intelligent driving sensors such as the vehicle-mounted laser radar, the camera and the like detect the external driving environment and the information of obstacles around the vehicle and transmit the information to the drive-by-wire chassis system through the vehicle-mounted network, the drive-by-wire chassis system completes independent braking and independent driving operation instructions of independent wheels by using corresponding control strategies according to the external environment and the information of the obstacles, and the drive-by-wire chassis control system and the intelligent sensor system comprehensively realize the stability and the safety of the vehicle in the driving process.
The invention relates to a three-axis six-wheel vehicle, which is characterized in that a driving road environment and obstacle information acquisition is carried by a vehicle self-carrying sensor through information interaction among vehicles, so that the vehicle head and the vehicle tail are actively prevented from collision when the three-axis six-wheel vehicle longitudinally runs, and the longitudinal control of a drive-by-wire chassis is completed through six-wheel independent driving and six-wheel independent braking, so that the safety and the stability of the vehicle when the vehicle longitudinally runs are ensured.
When the chassis anti-collision control system is used for controlling a three-axis six-wheel vehicle, the independent wheel-by-wire brake system is a six-wheel independent wire-controlled drive system, the six wheels are driving wheels, and each driving wheel comprises a driving mode, a follow-up mode and a vent mode: the driving mode is that the wheels are in contact with the ground, the suspension where the wheels are located is in a state of supporting the working state of the vehicle body, and the driving motor of the driving mode is in a working state; the following mode is that wheels are in contact with the ground, a suspension where the wheels are located is in a state of supporting the working of a vehicle body, but a driving motor does not work, and when other driving wheels drive the vehicle to run, the vehicle runs to drive the wheels in the following mode to rotate; the emptying mode means that wheels are not in contact with the ground, the suspension at the wheels controls the wheels to be in a lifting state, the driving motor does not work, and the wheels do not rotate.
Preferably, the driving wheels of a first shaft at the front end of the vehicle and a third shaft at the tail end of the vehicle adopt a wheel edge driving mode, the driving wheel of a second shaft in the middle of the vehicle adopts a wheel hub motor driving mode, wheel edge (motor) driving is driven by permanent magnet wheel edge motors arranged on two sides of an axle, a motor, a speed reducer mechanism and a wheel hub are highly integrated into a wheel edge motor driving axle which is applied to the first shaft and the third shaft of a wire-controlled chassis vehicle type vehicle, the wheel hub motor driving adopts a high-speed inner rotor motor, and the driving motors are integrated into the wheel hub. According to the drive control parameters fed back by the chassis anti-collision control system, the six independent drive wheels are respectively distributed in one of a drive mode, a follow-up mode and an emptying mode, so that the arbitrary combination from single wheel drive to six-wheel drive of the whole vehicle is realized.
The first shaft at the front end of the vehicle and the third shaft at the tail end of the vehicle adopt electro-hydraulic coupling braking, and the second shaft in the middle of the vehicle adopts electromechanical braking. The six-wheel independent brake-by-wire system comprises two brake systems, namely electro-hydraulic coupling brake and electronic mechanical brake, wherein the brake systems of three shafts of a chassis-by-wire vehicle are different in application, the electro-hydraulic coupling brake systems are applied to the wheels of a first shaft and the wheels of the three shafts, and the electronic mechanical brake systems are applied to the wheels of a second shaft.
Preferably, the six-wheel independent brake-by-wire system comprises a vehicle body stabilizing module and a brake delay compensating module, and the vehicle body stabilizing module and the brake delay compensating module are used for ensuring vehicle stability and rapid braking. The vehicle body stabilizing module can be composed of two parts, namely a vehicle body stabilizing control system A composed of a first shaft and a third shaft and a vehicle body stabilizing control system B of an electronic mechanical braking system of the second shaft, and when the three shafts of the vehicle work normally and all wheels are not in an emptying mode, the vehicle body stabilizing control system A and the vehicle body stabilizing control system B work simultaneously; when the second shaft is in the emptying mode, only the vehicle body stability control system A works normally, and at the moment, the four-wheel independent brake control states of the first shaft and the third shaft are as follows:
in the formula,. DELTA.M Z The desired yaw moment for the vehicle in Nm; f' x2 Longitudinal braking force of the wheel on the right side of the first shaft; Δ F Y2 The variable quantity of the ground lateral acting force of the wheel on the right side of the first shaft; f' x6 Longitudinal braking force of the right wheel of the third shaft; Δ F Y6 The variable quantity of the ground lateral acting force of the wheel on the right side of the first shaft is N; l 1 The horizontal longitudinal distance from the axle center of a first axle of the vehicle to the center of mass; l 3 The horizontal longitudinal distance from the axle center of the third shaft of the vehicle to the center of mass is meter; b is 1 The distance from the center of the left wheel and the center of the right wheel of the first shaft to the shaft center; b is 3 The distance from the center of the left and right wheels of the third shaft to the axle center is meter; f' X1 Longitudinal braking force of a wheel on the left side of the first shaft; Δ F Y1 The variable quantity of the ground lateral acting force of the wheel on the left side of the first shaft; f' X5 Longitudinal braking force of the left wheel of the third shaft; Δ F Y5 The variable quantity of the ground lateral acting force of the wheel on the left side of the first shaft; delta. For the preparation of a coating 1 、δ 2 、δ 5 、δ 6 The turning angles of the left and right wheels of the first shaft and the left and right wheels of the third shaft are respectively, and the unit is rad.
When the second shaft is in the emptying mode and only the wheels of the first shaft and the third shaft brake to work, the wheel cylinder pressure values of the four wheels are respectively as follows for maintaining the stability of the vehicle body after simplification:
in the formula, p 1 、p 2 、p 5 、p 6 The brake pressures of the left and right wheels of the first shaft and the left and right wheels of the third shaft are respectively in MPa; f Z1 、F Z2 、F Z5 、F Z6 The ground vertical acting forces of the left and right wheels of the first shaft and the left and right wheels of the third shaft are respectively expressed by N; r w1 、R w3 The radius of the wheels on the first shaft and the third shaft is respectively, and the unit is meter; k b The brake pressure coefficient is the ratio of the wheel brake torque to the wheel cylinder pressure; Δ M Z The desired yaw moment for the vehicle in Nm; b is 1 The distance from the center of the left and right wheels of the first shaft to the shaft center, B 3 The distance from the center of the left and right wheels of the third shaft to the axle center is meter; delta. For the preparation of a coating 1 、δ 2 、δ 5 、δ 6 The turning angles of the left and right wheels of the first shaft and the left and right wheels of the third shaft are respectively, and the unit is rad.
The braking delay compensation module is used for compensating braking delay caused by action delay and communication delay of the brake, and preferably, the calculation formula of the pressure value of the compensated wheel cylinder is as follows:
in the formula, p com To compensate for wheel cylinder pressure value, t 1 For communication delay time, t 2 ' time taken for brake clearance reduction, t 2 "is the time for the brake to gradually compress to be stable, p (t) is the pressure value of the brake wheel cylinder at the moment t, and the unit is MPa; t from the start of brake application 1 +t 2 ’+t 2 In the "/2 time period, p pro The value is 30-80% of the maximum wheel cylinder pressure value, and the unit is MPa, p pro The value of (d) depends on the brake deceleration value in the chassis collision avoidance control system:
pro＝30 a＜2.5m/s 2
pro＝30+k bra (a bra -2.5) 2.5m/s 2 ≤a≤7.5m/s 2
pro＝80 a＞7.5m/s 2
in the formula, k bra For braking deceleration scale factor, a bra For the feedback braking deceleration in the chassis collision avoidance control system, when the braking deceleration is less than 2.5m/s 2 When is, p pro Taking a value of 30, when the braking deceleration is more than 7.5m/s 2 When is, p pro Taking the value of 80.
The vehicle-vehicle communication system is used for information interaction with a drive-by-wire chassis vehicle type vehicle and information interaction between the drive-by-wire chassis vehicle type vehicle and other vehicles, and the interaction information comprises basic vehicle position information and vehicle motion state information (comprising the longitudinal position x of the drive-by-wire chassis vehicle type vehicle) wi (ii) a Transverse position y of a chassis-by-wire vehicle wi In the unit m; speed v of a Chassis-by-wire vehicle wi The unit is m/s; acceleration a of a Chassis-by-wire vehicle wi In the unit of m/s 2 ) And expected behavior of the Chassis System for Chassis-by-wire type vehicle (comprising six wheel drive torques T) di Six wheel brake cylinder pressure p i Wherein i =1 \ 82306).
The vehicle-vehicle communication system adopts a multi-member hierarchical intercommunication communication mode, vehicles participating in communication comprise a wire-control chassis vehicle type vehicle, a non-wire-control chassis vehicle type vehicle carrying a laser radar and a camera, and a non-wire-control chassis radar-free camera vehicle, and the communication is divided into three-level intercommunication communication modes:
the first-level communication is information interaction with a vehicle of a wire-controlled chassis vehicle type, the second-level communication is started after the first-level communication is successfully interconnected, the second-level communication is information interaction with a vehicle of a non-wire-controlled chassis vehicle type carrying a laser radar and a camera, the information interaction level of a vehicle which does not finish information interaction within set interaction time is reduced to third-level communication, and the third-level communication is information interaction with a vehicle without a radar camera of the non-wire-controlled chassis and a vehicle which does not successfully interact with the second-level communication. The intercommunication communication mode adopts a multi-vehicle full-duplex multi-channel mode, and ensures that a plurality of wire-controlled chassis vehicle type vehicles receive and transmit communication information simultaneously.
The cloud communication system can store and record the environment of the vehicle of the line control chassis vehicle type and the driving environment information data transmitted by the obstacle detection system, send the driving environment information data to other vehicles, receive the state information of other vehicles and send the state information to the vehicle of the line control chassis vehicle type, and the cloud communication system performs information fusion with the obstacle information detected by the environment and obstacle detection system and the interaction information of the vehicle-vehicle communication system. The information receiving and sending function of the cloud communication system can assist vehicle-to-vehicle communication of the drive-by-wire chassis vehicle type, real-time information interaction can be carried out on other vehicles and the drive-by-wire chassis vehicle type, information of other vehicles is received by the cloud and broadcast is carried out, intercommunication and interconnection of all vehicles are achieved, and meanwhile, the vehicles which are not provided with the laser radar and the camera can receive running road environment information stored by the cloud.
Correspondingly, the chassis collision avoidance control system comprises a collision avoidance mode with a communication function and a collision avoidance mode without the communication function:
anticollision mode with communication function: judging the collision risk of the self-vehicle according to the obstacle information data integrated by the environment and obstacle detection system, the vehicle-vehicle communication system and the cloud communication system, and deciding the execution actions of all systems of the wire control chassis by using the obstacle data and a corresponding control strategy to avoid collision with a dynamic and static obstacle;
the collision avoidance method comprises the following steps of judging the collision risk of a vehicle according to the environment and dynamic and static barrier information collected by a barrier detection system, deciding the execution actions of each system of a linear control chassis by using barrier data and a corresponding control strategy (a sliding mode control strategy can be selected), and avoiding collision with the dynamic and static barriers, wherein the specific algorithm is as follows:
a) And setting the longitudinal distance d (t) between two adjacent vehicles at the moment t as follows:
d(t)＝x f (t) -x (t) or d (t) = x (t) -x r (t)
In the formula, x f (t) longitudinal position of front vehicle of drive-by-wire chassis vehicle type at time t: (That is, the longitudinal position of the front vehicle of the drive-by-wire chassis vehicle type varies with time, the following definitions are similar and are not repeated, and x (t) is the longitudinal position of the drive-by-wire chassis vehicle type at the time t, and x r (t) the longitudinal position of the rear vehicle of the line control chassis vehicle type at the time t, wherein the unit is meter;
b) the calculation formula of the longitudinal driving force or the longitudinal braking force controlled by the chassis anti-collision control system at the moment t is as follows:
in the formula, F (t) is longitudinal driving force or braking force of the vehicle at the time t, and the unit is N; m is the total vehicle mass of the self vehicle; q and k are integral sliding mode coefficients; lambda [ alpha ] 1 In order to improve the headway coefficient; f a (t)、F r (t) air resistance and rolling resistance at time t, respectively, in units of N;
a first derivative of the longitudinal position error value of the adjacent vehicle at the time t;
the second derivative of the longitudinal position error value of the adjacent vehicle at the time t; a is des (t) obtaining the expected acceleration of the self-vehicle by a sliding mode control strategy at the time t; v. of 1 And v 2 The unit is m/s, and the unit is the longitudinal speed of a front vehicle and the longitudinal speed of a rear vehicle in two adjacent vehicles respectively; the corresponding control strategy is a sliding mode control strategy, is suitable for a system for protecting the front end collision and the rear end collision of the self-vehicle, and selects a sliding mode surface containing an integral term and an approach law respectively as follows:
in the formula, lambda is an integral sliding mode coefficient and is dimensionless, e (t) is a longitudinal position error value of two adjacent vehicles at the time t, and the unit is m; s is i Is a sliding mode surface, G is a normal number, wherein e (t) can be calculated according to the actual distance between the drive-by-wire chassis vehicle and the front and rear vehicles at the time t and the longitudinal expected distance between the self vehicle and the front vehicle:
e(t)＝d(t)-d x,des (t)
in the formula (d) x,des (t) the longitudinal expected distance between the self vehicle and the front vehicle at the time t, and the unit is meter;
c) The protection front-end collision system judges the risk of collision between the head of the self vehicle and the front vehicle, and when the difference between the longitudinal position of the vehicle closest to the front of the self vehicle and the longitudinal position of the self vehicle is smaller than an expected distance, the protection front-end collision system is started, wherein the calculation formula of the longitudinal expected distance between the self vehicle and the front vehicle is as follows:
in the formula, d x,des The expected distance between the self vehicle and the front vehicle; v. of x The longitudinal speed of the bicycle; v. of x,f The longitudinal speed of the front vehicle; a is a x Is the longitudinal acceleration of the bicycle; a is a x,f Longitudinal acceleration of the front vehicle; lambda 1 In order to improve the headway coefficient; lambda [ alpha ] 2 Is a speed proportionality coefficient; lambda 3 Is an acceleration difference coefficient; d is the minimum driving distance of the vehicle and has the unit of m;
in the front end collision protection system, when the road surface adhesion coefficients of roads are the same, the left and right braking force distribution of each axle is the same, the braking force distribution proportion of the wheels of a first axle is fixed, the braking force distribution of a second axle and a third axle is determined by the braking acceleration, and the braking force distribution formula is as follows:
F 1,bra ＝0.4F bra
in the formula, F 1,bra 、F 2,bra 、F 3,bra Braking forces distributed to wheels of the first shaft, the second shaft and the third shaft respectively; a is a bra Is the braking deceleration; f bra Is braking force;
d) The rear-end collision protection system judges the risk of collision between the tail of the bicycle and the rear bicycle, when the longitudinal distance between the bicycle and the rear bicycle is smaller than the expected distance and the front vehicle, the barrier or the front vehicle barrier is not threatened, the rear-end collision protection system is started, the bicycle is in an acceleration state, and the longitudinal expected distance calculation formula between the bicycle and the rear bicycle is as follows:
in the formula (d) x,des’ The expected distance between the self vehicle and the front vehicle; v. of x The longitudinal speed of the bicycle; v. of x,r The longitudinal speed of the rear vehicle; a is x Is the self-vehicle longitudinal acceleration; a is a x,r Longitudinal acceleration of the rear vehicle; lambda [ alpha ] 1 For improving headway factor, λ 2 Is a speed proportionality coefficient, λ 3 D is the minimum driving distance of the vehicle and the unit is m;
in the rear-end collision protection system, when the road surface adhesion coefficients of roads are the same on the left and right sides, the left and right driving force distribution of each axle is the same, the driving force distribution proportion of the wheels of the first axle is fixed, the driving force distribution of the second axle and the third axle is determined by the acceleration, and the driving force distribution formula is as follows:
F acc,1 ＝0.3F acc
in the formula, F acc,1 、F acc,2 、F acc,3 Driving forces distributed to the wheels of the first shaft, the second shaft and the third shaft respectively; a is a acc Is the acceleration; f acc Is a driving force;
e) When two adjacent vehicles are wire-controlled chassis vehicle type vehicles, if the actual longitudinal distance between the two vehicles is smaller than the expected longitudinal distance between the two vehicles, the protection rear-end collision system of the front vehicle and the protection front-end collision system of the rear vehicle work simultaneously, the front vehicle is in an acceleration state, the rear vehicle is in a deceleration state, and the front vehicle and the rear vehicle start the protection collision systems simultaneously to shorten the variable speed movement time of the vehicles.
The invention discloses a longitudinal active anti-collision control system and a longitudinal active anti-collision control method, which aim to solve the safety problem when a vehicle runs at a high speed in the longitudinal direction, and aim at the complicated road change, the unfixed motion state of surrounding vehicles and the position influence of obstacles.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (7)
1. A longitudinal active anti-collision control system comprises an environment and obstacle detection system, and is characterized by further comprising a chassis anti-collision control system, a wheel independent line-control driving system and a wheel independent line-control braking system, wherein the chassis anti-collision control system comprises a front-end collision protection system and a rear-end collision protection system, the wheel independent line-control driving system is used for applying independent driving force to each wheel of a vehicle, the wheel independent line-control braking system is used for applying independent braking force to each wheel of the vehicle, and the chassis anti-collision control system controls the braking force and the driving force of each wheel according to the information collected by the environment and obstacle detection system so that the vehicle can realize front-end collision protection and rear-end collision protection; the wheel independent brake-by-wire system comprises a vehicle body stabilizing module and a brake delay compensation module, wherein the vehicle body stabilizing module is used for ensuring the stability of a vehicle, and the brake delay compensation module is used for compensating brake delay caused by brake execution action delay and communication delay;
the chassis anti-collision control system is used for controlling a three-axis six-wheel vehicle, the wheel independent drive-by-wire system is a six-wheel independent drive-by-wire system, the six wheels are all driving wheels, and each driving wheel comprises three working modes, namely a driving mode, a follow-up mode and a emptying mode;
the independent wheel wire-controlled brake system is a six-wheel independent wire-controlled brake system, and the vehicle body stabilizing module and the brake delay compensation module are used for ensuring the self stability and non-delay braking of the vehicle during the braking operation;
the driving wheels of the first shaft at the front end of the vehicle and the third shaft at the tail end of the vehicle adopt a wheel edge driving mode, the driving wheel of the second shaft in the middle of the vehicle adopts a hub motor driving mode, the first shaft at the front end of the vehicle and the third shaft at the tail end of the vehicle adopt electro-hydraulic coupling braking, and the second shaft in the middle of the vehicle adopts electromechanical braking;
when the second shaft is in the emptying mode and only the wheels of the first shaft and the third shaft brake and work, the wheel cylinder pressure values of the four wheels of the first shaft and the third shaft for braking are respectively as follows:
in the formula, p 1 、p 2 、p 5 、p 6 The braking pressures of the left and right wheels of the first shaft and the left and right wheels of the third shaft are respectively expressed in MPa; f Z1 、F Z2 、F Z5 、F Z6 The unit of the vertical ground acting force is N, and the vertical ground acting force is respectively the left and right wheels of the first shaft and the left and right wheels of the third shaft; r w1 、R w3 The radius of the wheels on the first shaft and the third shaft respectively, and the unit is meter; k b The brake pressure coefficient is the ratio of the wheel brake torque to the wheel cylinder pressure; Δ M Z The desired yaw moment for the vehicle in Nm; b is 1 The distance from the center of the left and right wheels of the first shaft to the shaft center, B 3 The distance from the center of the left and right wheels of the third shaft to the axle center is meter; delta 1 、δ 2 、δ 5 、δ 6 The rotation angles of the left and right wheels of the first shaft and the left and right wheels of the third shaft are respectively expressed in rad.
2. The longitudinal active collision avoidance control system of claim 1, further comprising a vehicle-to-vehicle communication system and a cloud communication system: the vehicle-vehicle communication system is used for information interaction between vehicles of a line-control chassis vehicle type and information interaction between the vehicles of the line-control chassis vehicle type and other vehicle types; the cloud communication system is used for recording the environment of the vehicle of the wire-controlled chassis vehicle type and the environment information data collected by the obstacle detection system, transmitting the environment information data to the vehicle of the non-wire-controlled chassis vehicle type, and simultaneously feeding the information record of the vehicle of the non-wire-controlled chassis vehicle type back to the vehicle of the wire-controlled chassis vehicle type to complete all information interaction of the road vehicle; the cloud communication system further comprises an information integration unit A, and the information integration unit A integrates information of information received by the cloud communication system, obstacle information detected by the environment and obstacle detection system, and interaction information of the vehicle-vehicle communication system.
3. A longitudinal active collision avoidance control system according to claim 2 wherein the environment and obstacle detection system comprises an intelligent look-around sensor system, a wheel center relative height gauge, an information integration unit B and a flatness information correction unit:
the intelligent all-round looking sensor system comprises a mechanical laser radar at the top of the vehicle head, a solid laser radar at the front part of the vehicle head, a binocular camera at the intersection of the top of the vehicle head and the front part and a monocular camera at the tail part of the vehicle;
the information integration unit B integrates information acquired by the mechanical laser radar and the binocular camera with vehicle interaction information acquired by a vehicle-vehicle communication system and a cloud communication system, so that the states of obstacles and surrounding vehicles are accurate;
and the flatness information correction unit corrects the flatness information of the road around the vehicle running, which is acquired by the solid-state laser radar and the wheel center relative height measuring instrument.
4. The longitudinal active collision avoidance control system according to claim 1, wherein the compensated wheel cylinder pressure value of the brake delay compensation module is:
in the formula, p com To compensate for wheel cylinder pressure value, t 1 For communication delay time, t 2 ' time taken for brake clearance reduction, t 2 "time taken for the brake to gradually compress to stabilize, t after the brake starts to act 1 +t 2 ’+t 2 In "/2 time period, p pro The value is 30 to 80 percent of the maximum wheel cylinder pressure value and the unit is MPa, p pro The value of (b) depends on the braking deceleration value in the chassis anti-collision control system, and p (t) is the pressure value of the brake wheel cylinder at the moment t and has the unit of MPa.
5. The longitudinal active collision avoidance control system according to claim 3, wherein the correction formula of the flatness information correction unit is:
in the formula, h n,i The relative height of the ith rough road surface low obstacle around the corrected vehicle is obtained; h' n,i And h' n,i The relative height of the i-th rough road around the vehicle, which is measured by the solid laser radar detection and the wheel center relative height measuring instrument, is measured in meters; v. of x Is the longitudinal speed of the vehicle, and the unit is m/s; k is a radical of formula vx And the unit is m/s, which is a longitudinal vehicle speed influence factor.
6. The longitudinal active collision avoidance control system according to claim 3, wherein the information integration unit B integrates the following obstacle information:
in the formula, x cj 、y cj 、v cj 、a cj Respectively acquiring the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the jth dynamic barrier around the vehicle by using the binocular camera; x is a radical of a fluorine atom dj 、y dj 、v dj 、a dj Respectively acquiring the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the jth dynamic obstacle around the vehicle by the mechanical laser radar; x is a radical of a fluorine atom wi 、y wi 、v wi 、a wi Respectively detecting the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the ith chassis-by-wire vehicle type vehicle detected by a vehicle-to-vehicle communication system; x is the number of i 、y i 、v i 、a i Respectively the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the integrated ith line-controlled chassis vehicle type vehicle; x is a radical of a fluorine atom n-i 、y n-i 、v n-i 、a n-i The method is characterized in that the method comprises the steps of integrating the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of a non-wire control chassis vehicle type vehicle, wherein n is the number of dynamic obstacles detected by a mechanical laser radar, and j =1 \ 8230n; k is a radical of formula w The interactive information accuracy coefficient; k is a radical of d Is radar information accuracy coefficient; k is a radical of formula c Is a camera information accuracy coefficient, k w 、k d And k c Are all taken as valuesA positive number less than 1; x is a radical of a fluorine atom d，n-i 、y d，n-i 、v d，n-i 、a d，n-i Respectively acquiring the longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the nth-i dynamic obstacles around the vehicle by the mechanical laser radar; x is a radical of a fluorine atom c，n-i 、y c，n-i 、v c，n-i 、a c，n-i The longitudinal instantaneous position, the transverse instantaneous position, the instantaneous speed and the instantaneous acceleration of the nth-i dynamic obstacles around the vehicle are acquired by the binocular camera respectively.
7. A longitudinal active anti-collision control method is characterized in that a chassis anti-collision control system comprises an anti-collision mode with a communication function and an anti-collision mode without the communication function:
anticollision mode with communication function: judging the collision risk of the self-vehicle according to the obstacle information data integrated by the environment and obstacle detection system, the vehicle-vehicle communication system and the cloud communication system, and deciding the execution actions of all systems of the wire control chassis by using the obstacle data and a corresponding control strategy to avoid collision with a dynamic and static obstacle;
the anti-collision mode without a communication function judges the collision risk of the self-vehicle only according to the environment and the dynamic and static obstacle information acquired by the obstacle detection system, decides the execution actions of all systems of the wire control chassis by using the obstacle data and a corresponding control strategy and avoids the collision with the dynamic and static obstacles, and the specific algorithm is as follows:
a) And setting the longitudinal distance d (t) between two adjacent vehicles at the time t as follows:
d(t)＝x f (t) -x (t) or d (t) = x (t) -x r (t)
In the formula, x f (t) is the longitudinal position of the front vehicle of the line-control chassis vehicle type at the time t, x (t) is the longitudinal position of the line-control chassis vehicle type at the time t, x r (t) the longitudinal position of the rear vehicle of the line control chassis vehicle type at the time t, wherein the unit is meter;
b) the calculation formula of the longitudinal driving force or the longitudinal braking force controlled by the chassis anti-collision control system at the moment t is as follows:
in the formula, F (t) is longitudinal driving force or braking force of the vehicle at the time t, and the unit is N; m is the total vehicle mass of the self vehicle; q and k are integral sliding mode coefficients; lambda [ alpha ] 1 In order to improve the headway coefficient; f a (t)、F r (t) air resistance and rolling resistance at time t, respectively, in units of N;
the first derivative of the error value of the longitudinal position of two adjacent vehicles at the time t;
is a second derivative of the error value of the longitudinal position of two adjacent vehicles at the time t; a is a des (t) obtaining the expected acceleration of the self-vehicle by a sliding mode control strategy at the time t; v. of 1 And v 2 Respectively the longitudinal speed of the front vehicle and the longitudinal speed of the rear vehicle in two adjacent vehicles, and the unit is m/s;
in the formula, e (t) is the error value of the longitudinal position of two adjacent vehicles at the time t, and the unit is m; s is i Is a slip form surface, G is a normal number;
c) The protection front-end collision system judges the risk of collision between the head of the self vehicle and the front vehicle, and when the difference between the longitudinal position of the vehicle closest to the front of the self vehicle and the longitudinal position of the self vehicle is smaller than an expected distance, the protection front-end collision system is started, wherein the calculation formula of the longitudinal expected distance between the self vehicle and the front vehicle is as follows:
in the formula (d) x,des The expected distance between the self vehicle and the front vehicle; v. of x The longitudinal speed of the bicycle; v. of x,f The longitudinal speed of the front vehicle; a is x Is the self-vehicle longitudinal acceleration; a is x,f Longitudinal acceleration of the front vehicle; lambda 1 In order to improve the headway coefficient; lambda [ alpha ] 2 Is a speed proportionality coefficient; lambda [ alpha ] 3 Is an acceleration difference coefficient; d is the minimum driving distance of the vehicle and the unit is m;
starting a front-end collision protection system, wherein a braking force distribution formula is as follows:
F 1,bra ＝0.4F bra
in the formula, F 1,bra 、F 2,bra 、F 3,bra Braking forces distributed to wheels of the first shaft, the second shaft and the third shaft respectively; a is bra For braking deceleration; f bra Is the braking force;
d) The rear-end collision protection system judges the risk of collision between the tail of the bicycle and the rear bicycle, when the longitudinal distance between the bicycle and the rear bicycle is smaller than the expected distance and the front vehicle, the barrier or the front vehicle barrier is not threatened, the rear-end collision protection system is started, the bicycle is in an acceleration state, and the longitudinal expected distance calculation formula between the bicycle and the rear bicycle is as follows:
in the formula (d) x,des’ The expected distance between the self vehicle and the front vehicle; v. of x The longitudinal speed of the vehicle is the self longitudinal speed; v. of x,r The longitudinal speed of the rear vehicle; a is x Is the longitudinal acceleration of the bicycle; a is x,r Longitudinal acceleration of the rear vehicle; lambda [ alpha ] 1 For improving headway factor, λ 2 Is a speed proportionality coefficient, λ 3 D is the minimum driving distance of the vehicle and the unit is m;
starting a rear-end collision protection system, wherein the driving force distribution formula is as follows:
F acc,1 ＝0.3F acc
in the formula, F acc,1 、F acc,2 、F acc,3 Driving forces distributed to wheels of the first shaft, the second shaft and the third shaft respectively; a is acc Is the acceleration; f acc Is a driving force;
e) When two adjacent vehicles are of a wire-control chassis vehicle type, if the actual longitudinal distance between the two vehicles is smaller than the expected longitudinal distance between the two vehicles, the protection rear-end collision system of the front vehicle and the protection front-end collision system of the rear vehicle work simultaneously, the front vehicle is in an acceleration state, the rear vehicle is in a deceleration state, and the front vehicle and the rear vehicle start the protection collision systems simultaneously.
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| CN113378947A (en) * | 2021-06-21 | 2021-09-10 | 北京踏歌智行科技有限公司 | Vehicle road cloud fusion sensing system and method for unmanned transportation in open-pit mining area |
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