Summary of the invention
The invention provides a kind of Initiative anti-collision method of vehicle with course changing control function, when system judges have collision risk in this track and cannot avoid, system carries out turning to judgement of escaping, and finds survival route by auto-steering.
Implementation of the present invention is as follows:
1, an Initiative anti-collision method of vehicle, comprises the following steps:
(1) standby mode: real-time detection collection, from the speed of car and surrounding vehicles, acceleration/accel and relative position information, judges whether have collision risk with front truck in same track: without dangerous, continue step (1) if judge; If judge there is collision risk, proceed to step (2);
(2) autobrake pattern:
(A) judge whether to avoid colliding in this track by autobrake:
If a () to judge in this track that autobrake can collision free, proceed to step (B);
If b () judges that autobrake cannot collision free, but during by turning to escape collision free, turning angle of steering wheel when determining that Vehicular turn is escaped, proceeds to step (3);
If c () judges that autobrake cannot collision free, auto-steering escape also cannot collision free time, proceed to step (B);
(B) brake in this track, and give a warning;
(3) auto-steering pattern: based on turning angle of steering wheel angle when determining that Vehicular turn is escaped in step (2), carry out turning to escape.
Described step (2), with described step (3), if judge dangerous releasing, proceeds to standby mode in step (1).
Also comprise initialization step before described step (1), whether detection hardware status of equipment is good, rotates forward, proceed to step (1) if hardware device runs.
Also comprise interrupt step in described initialization step, waiting step, autobrake step and auto-steering step, when monitoring the operation of described equipment and breaking down, interrupt former algorithm, proceed to failure mode.
Based on the spacing S from car and front truck in step (a)
1and from car first acceleration/accel and front truck acceleration/accel, judge that in this track, whether autobrake collision can occur by collision free, comprises the following steps:
1) calculating reduces speed now braking to stopping the required time completely from car from car with the first acceleration/accel;
2) calculate in braking time respectively, from the stopping distance of car and the stopping distance of front truck, and calculate the difference of the stopping distance of two cars;
3) more described spacing S
1with the difference of described stopping distance: if the difference of the stopping distance of two cars is less than spacing S
1, judge that in this track, collision can be avoided, and brakes with described first acceleration/accel, and sends warning; If the difference of the stopping distance of two cars is greater than spacing S
1, judge collide in this track, proceed to step (b).
Described first deceleration acceleration/accel is 0.7g, g is acceleration due to gravity.
In described step (b), comprise the following steps: setting vehicle forward direction is first direction, and second direction is arranged perpendicular to described first direction,
I, maximum steering wheel angle of escaping is determined: calculate maximum Vehicular turn angle when Vehicular turn is escaped, and determine based on described maximum Vehicular turn angle the maximum steering wheel angle angle that Vehicular turn is escaped;
II, collision scope is determined: based on described maximum Vehicular turn angle and the position relationship from car and adjacent lane target vehicle, when calculating collides to the track of target vehicle traveling and target vehicle from car escape, the displacement S of target vehicle from reference position to position of collision
2, set certain allowance γ, with (S simultaneously
2-γ, S
2+ γ) as collision scope;
III, based target vehicle speed, calculate and turn to escape in the time period of target setting position from car, target vehicle is along the displacement l of first direction
o2x;
IV, more described displacement l
o2xwith described collision scope, if displacement l
o2xbe within the scope of described collision, then, when judging to turn to escape, collide still inevitable; If displacement l
o2xnot belonging to described collision scope, judging according to determining in step (I) that maximum steering wheel angle degree carries out turning to escape.
Described step (I) comprise the following steps:
1) vehicle minimum turning radius is calculated;
2) determine based on geometric relationship and described minimum turning radius corresponding to the car maximum Vehicular turn angle β number of degrees;
3) determine that described maximum steering wheel angle vehicle corner determines maximum steering wheel angle based on described maximum vehicle corner, described maximum vehicle corner and the described maximum steering wheel angle number of degrees linear.
Described step (II) comprise the following steps:
1) read when car turns to escape, with adjacent lane target vehicle in a first direction and a second direction distance from the distance l of car
1and b
1;
2) based on geometric relationship, calculate when vehicle turns to escape with maximum Vehicular turn angle, when car travels the track to target vehicle, along the displacement l of first direction
2; Described displacement S
2for described l
1with described l
2sum.
Described step (III) comprise the following steps:
1) based on geometric relationship, determine to turn to escaping distance from car;
2) based on escape time from vehicle speed, the second acceleration/accel and described escaping distance l
3determine to turn to slip time t from car
es;
3) slip time t is turned to based on described
esand target vehicle velocity, determine the displacement l of the second vehicle
o2x.
Described second deceleration acceleration/accel is 0.7g, g is acceleration due to gravity.
Beneficial effect of the present invention is as follows:
Auto-steering function is added on the basis of the anti-central collision system of tradition, and algorithm logic adds corresponding judgement, when by system, frontal collisions is judged as that direct self-actuating brake cannot be avoided, system starts detection and calculates whether there is survival route around, after system-computed goes out the path that can escape, system just starts to start auto-steering function, thus successfully avoids the generation of accident.
Detailed description of the invention
As shown in Figure 1, a kind of Initiative anti-collision method of vehicle, comprises the following steps:
(1) standby mode: real-time detection collection, from the speed of car and surrounding vehicles, acceleration/accel and relative position information, judges whether have collision risk with front truck in same track: without dangerous, continue step (1) if judge; If judge there is collision risk, proceed to step (2);
In the present embodiment, by monitoring front vehicle speed, judged whether collision risk, if the monitoring front truck speed of a motor vehicle reduces suddenly, then system judges there is collision risk.
(2) autobrake pattern:
(A) judging whether can by autobrake collision free in this track:
If a () to judge in this track that autobrake can collision free, proceed to step (B);
If b () judges that autobrake cannot collision free, but during by turning to escape collision free, turning angle of steering wheel when determining that Vehicular turn is escaped, proceeds to step (3);
If c () judges that autobrake cannot collision free, auto-steering escape also cannot collision free time, proceed to step (B);
(3) auto-steering pattern: based on turning angle of steering wheel angle when determining that Vehicular turn is escaped in step (2), carry out turning to escape.
Wherein, in step (a) based on the spacing S from car and front truck
1and from car first acceleration/accel and front truck acceleration/accel, judge that in this track, whether autobrake collision can occur by collision free, comprises the following steps:
1) calculating starts braking, until stop the required time completely from car from car with the first acceleration/accel;
2) calculate respectively in braking time, from the stopping distance S of car
exand the stopping distance S of front truck
ox, and calculate the difference of the stopping distance of two cars;
3) by the difference of the stopping distance of two cars and spacing S
1compare: if the difference of the stopping distance of two cars is less than spacing S
1, judge that in this track, collision can be avoided, self-actuating brake, and send warning; If the difference of the stopping distance of two cars is greater than spacing S
1, judge collide in this track.
Deterministic process is as follows: as shown in Figure 2, when automobile judge have collision risk after, start automatic emergency brake system, now system record from the car speed of a motor vehicle be V
ex, setting the first deceleration acceleration/accel is a
ex, the speed of a motor vehicle and the deceleration/decel of front vehicles are respectively V
o1x, a
o1x.
1) system-computed is when front truck starts to brake, starts braking, until stop the required time completely from car from car simultaneously.System, via car speed sensor and radar observation system, can be known from vehicle velocity V
exwith acceleration/accel a
ex, therefore, by formula V
o1x-a
o1xt=0, known from car braking time
2) calculate when starting braking from car in complete standing time, from car and target vehicle operating range separately.It can thus be appreciated that
3) judge in this track, whether collision can be avoided.Knownly to travel, if move forward from car, from car stopping distance S with current state respectively from car and front truck if analyzed
exdistance is greater than front truck travelling brake distance S
o1xwith two car spacing S1, then illustrate that collision is inevitable.
Therefore, S is worked as
ex-S
o1x< S
1, judge that collision can be avoided, now system autobrake, and carry out alarm;
Work as S
ex-S
o1x>=S
1time, judge that collision cannot be avoided, now can system escape starting calculating by turning to,
Proceed to step (3).
In the present embodiment, the first deceleration acceleration/accel a
exsize be 0.7g, wherein g is Free Falling Object And Acceleration of Gravity.
In step (b), based on deflection angle and the position relationship from car and adjacent lane target vehicle, when judging that Vehicular turn is escaped, whether collide with target vehicle: if collide inevitable, the braking with all strength in former track; Otherwise, undertaken turning to escape by determining that steering angle turns to.Comprise the following steps:
Setting vehicle forward direction is first direction, and second direction is arranged perpendicular to described first direction, and as shown in the figure, in the present embodiment, first direction is x direction, and second direction is y direction.
I, maximum steering wheel angle of escaping is determined: calculate maximum Vehicular turn angle when Vehicular turn is escaped, and determine based on described maximum Vehicular turn angle the maximum steering wheel angle angle that Vehicular turn is escaped;
II, collision scope is determined: based on described maximum Vehicular turn angle and the position relationship from car and adjacent lane target vehicle, when calculating collides to the track of target vehicle traveling and target vehicle from car escape, the displacement S of target vehicle from reference position to position of collision
2, set certain allowance γ, with (S simultaneously
2-γ, S
2+ γ) as collision scope;
III, based target vehicle speed, calculate and turn to escape in the time period of target setting position from car, target vehicle is along the displacement l of first direction
o2x;
IV, more described displacement l
o2xwith described collision scope, if displacement l
o2xbe within the scope of described collision, then, when judging to turn to escape, collide still inevitable; If displacement l
o2xnot belonging to described collision scope, judging according to determining in step (I) that maximum steering wheel angle degree carries out turning to escape.
In step (I), when the vehicle is running, when the speed of a motor vehicle is too high, if steering wheel angle is excessive will cause sideslip or roll-over accident, therefore all should there is the restriction of maximum steering wheel angle for the different speed of a motor vehicle.Vehicle is when turning to, and owing to being subject to the effect of centnifugal force, vehicle has the trend occurring to break away, and the value of this centnifugal force is relevant with the speed of a motor vehicle and turn radius, and under the same speed of a motor vehicle, the less then centnifugal force of turn radius is larger; Simultaneously because the existence of friction force can suppress the generation of breakking away, therefore under the identical speed of a motor vehicle, the system when centnifugal force is greater than friction force, can obtain the minimum turning radius R of vehicle
min, now corresponding maximum vehicle corner β
max.Again because steering wheel angle α and vehicle turn radius and rear axle angle β linear, i.e. β=k α; Wherein k can obtain according to automobile dynamic quality relevant knowledge; Therefore, when choosing minimum turning radius R
minduring as vehicle turn radius, Vehicular turn angle is maximum, also correspond to the maximum steering wheel angle number of degrees of vehicle.
When choose maximum steering wheel angle as turn to escape angle carry out escape can ensure not overturn at vehicle, realize to greatest extent Vehicular turn escape.
Steering wheel for vehicle steering locking angle is determined to comprise the following steps:
1) vehicle minimum turning radius R is determined
min;
When being V from the car speed of a motor vehicle
extime (not considering the speed of a motor vehicle in the vertical), the size of the centnifugal force suffered by vehicle:
Now, the size F of the side-friction force suffered by vehicle
f=μm g:
If F
g=F
f, radius is now minimum turning radius R
min, so known:
2) calculate maximum vehicle corner based on geometric relationship: when vehicle is escaped with minimum turning radius, now the corner of vehicle corresponds to maximum vehicle corner β
max.
As shown in Figure 4, in figure, l is vehicle antero posterior axis wheelbase, as seen from the figure,
Namely
So
3) maximum steering wheel angle is determined;
β=k α again
So maximum steering wheel angle can be learnt
In step (II), displacement S
2determination comprise the following steps:
1) read now from car and adjacent lane target vehicle in a first direction and a second direction distance from the distance l of car
1and b
1
2) when vehicle starts Turning travel with β angle time, based on geometric relationship, calculate when car travels the track to target vehicle, from car along the displacement l of first direction
2; Described displacement S
2for described l
1with described l
2sum.
Concrete computation process is as follows: as shown in Figure 5, supposes to carry out turning to escape from car, if when travelling to track, target vehicle place, just in time bump against with target vehicle, vehicle escape paths now as shown in Figure 5, supposes that vehicle is that particle is described herein.
Can learn from Fig. 5, according to geometric relationship, the displacement S of target vehicle
2comprise two segment distances: target vehicle backwardness is from spacing l
1with from car along the displacement l of first direction
2.
Wherein, l
1size can obtain by direct detection via the detection system of the radar sensor be positioned on vehicle, displacement l
2concrete computation process is as follows:
Analyze known according to Fig. 5: l
2=b
1tan β, wherein β is for turn to escape angle from car, has calculated and has learnt, therefore, can know displacement S in step (2)
2size.
Due to we suppose vehicle be particle have ignored vehicle itself length on the impact of collision, simultaneously in order to obtain a safer escape interval, need at l
2basis on increase certain safety factor γ (size of γ value depends on the result of system calibrating), the interval of therefore colliding scope is ((l
1+ l
2-γ), (l
1+ l
2+ γ)).
In step (III), displacement l
o2xdetermination comprise the following steps:
1) based on geometric relationship, determine to turn to escaping distance l from car
3;
2) based on escape time from vehicle speed, the second acceleration/accel and escaping distance l
3determine to turn to slip time t from car
es; In the present embodiment, described second acceleration magnitude is 0.7g.
3) slip time t is turned to based on described
esand target vehicle velocity, determine the displacement l of target vehicle
o2x.
Concrete analysis process is as follows: in order to not disturb the normal traveling of fellow road-users, and the situation preventing adjacent lane chaufeur from not to be noted not carrying out from the escape of car braking occurs, therefore the target vehicle of system supposition adjacent lane when calculating escape route is with V
o2xthe speed of a motor vehicle at the uniform velocity travels (a
o2x=0).
As shown in Figure 4, wherein, l
3for from car from escaping into the distance travelled needed for adjacent lane from track, t
esfor from car from escaping into the time travelled needed for adjacent lane from track.V
o2xfor the speed of a motor vehicle of target vehicle, the second deceleration acceleration/accel is set to a
ex1, in the present embodiment, the second deceleration acceleration/accel is 0.7g, wherein g is Free Falling Object And Acceleration of Gravity.
From geometric relationship
Again by by distance computing formula, known
It can thus be appreciated that:
Owing to supposing that therefore the target vehicle of adjacent lane at the uniform velocity travels, the operating range of adjacent lane target vehicle
Therefore, escaping in the time of adjacent lane from car, if the target vehicle of adjacent lane is along first direction operating range l
o2x∈ ((l
1+ l
2-γ), (l
1+ l
2+ γ)), so think and cannot be escaped by auto-steering, otherwise, then carry out auto-steering escape according to selected steering wheel angle.
More than be in the present embodiment, when system judges there is collision risk, concrete method of operation and algorithm deterministic process.
Wherein in an embodiment, also comprise in step (2) and step (3) and dangerously removes determining step, if system judges dangerous releasing, proceed to the middle standby mode of step (1).If system is in autobrake pattern and turn in pattern, the condition of the generation danger before judgement is removed, then proceed in the standby mode of step (1).
Wherein in an embodiment, also comprise initialization step before step (1), in initialization step, whether detection hardware status of equipment is good, rotates forward, then proceed to step (1), carry out anti-collision monitoring if hardware device runs.
Wherein in an embodiment, in above-mentioned initialization step, waiting step, autobrake step and auto-steering step, also comprise interrupt step, when equipment operation is broken down described in system monitoring, interrupt former algorithm, proceed to failure mode.
Below in conjunction with automobile hardware device and working state of system transition graph to the above-mentioned collision-proof method with course changing control function
Principle of work be further expalined.
As shown in Figure 6, with a collision avoidance system for course changing control function, comprise the Body control module, instrument display, electronic stabilizing control system ESC, electronic power assist steering system EPS, sensor assembly and the environment detection module that are connected with bus CAN respectively.
Wherein, sensor assembly comprises the yaw angle sensor YAW-RATE, wheel speed sensing Speed-Sensor and the steering wheel angle sensor SAS that are connected with bus respectively.YAW-RATE is used for the yaw velocity providing Current vehicle to system; Speed-Sensor is for informing the current speed of a motor vehicle; SAS is used for the current steering wheel angle of detection vehicle, the athletic posture of monitor vehicle, and the steering wheel angle value required for calculating during system auto-steering.
Environment detection module comprises the radar detected module and camera module that are connected with bus respectively.
It is the radar of 77GHZ that radar module comprises three specifications, for detecting from car and the location information of surrounding vehicles and the velocity information of surrounding vehicles, wherein the control module of native system is integrated in the control module of front radar, for receiving process environment detection module and the data that transmit of sensor assembly, determine the safe condition from car according to above-mentioned data, send to system in good time report to the police, slow down, brake and the instruction of auto-steering.
In radar module, front radar is arranged in logo rear before vehicle, with vehicle respectively to axis angle be 0 ± 3 °, rear radar (left side) is arranged in rear bumper rear, it is 40 ± 3 ° with longitudinal direction of car axis angle, rear radar (right side) is also arranged in rear bumper rear, is also 40 ± 3 ° with longitudinal direction of car axis angle.To guarantee to realize the monitoring from car surrounding environment.
Camera module comprises two cameras, and backup radar module monitors is from the running environment of car, and camera (left side) is arranged in below the outside rear-view mirror of left side, radar other left field unlapped before and after covering; Side camera (right side) is arranged in below the outside rear-view mirror of left side, radar other right side area unlapped before and after covering.
The environment of the sensor module and environment detection module perception vehicle periphery, the data detected by sensor assembly and environment detection module, realize monitoring other vehicle within the scope of 360 ° around car.
Body control module comprises the car body controller be connected with bus and the system closing button be connected with car body controller respectively, brake lamp control module and steering indicating light control module.When passenger selects not need to open collision avoidance system, close this system by system closing button; When system judges to cause danger in vehicle travel process, when needing to avoid danger by car brakeing, system lights brake lamp by brake lamp control module, and prompting occupant vehicle is by emergency braking; When system judges that needs avoid danger by turning to, except lighting brake lamp, system also by steering indicating light control module, opens the steering indicating light of respective side during Vehicular turn, and around prompting, the navigating mate of other vehicles, is about to turn to from car.
ESC system is used for sending accekeration according to system control module in front radar, carries out autobrake; EPS is used for the steering wheel angle value sent according to system control module in front radar, carries out auto-steering.
Instrument display effect mainly realizes native system according to the instruction of control module and carries out man-machine mutual display.
When said system specific works, mode of operation transition graph as shown in Figure 7.Wherein, each condition in state transition diagram refers to following form.
When starting from car, when point fire screen is in IGN gear, system starts to carry out initialization and carries out self-inspection.System is in the process of carrying out hardware check, and not under command light glimmers, and prompting occupant carries out system hardware detection.If system to occur the faults such as total line dropout, hard error by network monitor during to system, system exits initialize mode, and proceeds to failure mode.If after confirming that hardware device is in normal condition, system initialization process completes, failure warning lamp extinguishes, and prompting vehicle arrangement is normal, and system starts, enters standby mode.
In standby mode, sensor assembly and environment monitoring module are monitored from car surrounding environment, when via the data that sensor assembly and environment monitoring module transmit, system judges that surrounding vehicles travels normally, when front does not detect danger, proceed standby mode, in the process, when system occurs the faults such as total line dropout, hard error by network monitor to system, failure mode is proceeded to.If system judges that surrounding vehicles normally travels, do not detect front and occur dangerous, continue to perform standby mode.
In above initialize mode and standby mode, if passenger presses closedown button, require system closing, then system goes to " shut " mode", and shows the printed words of " collision avoidance system closedown " by instrument display, and this system of prompting passenger is closed.
In standby mode, if after the information that provides of system process front radar and other equipment, judgement can collide with front truck, and system proceeds to autobrake pattern.
In autobrake pattern, if system to occur the faults such as total line dropout, hard error by network monitor during to system, " collision avoidance system fault " will be shown by instrument display display instrument, proceed to failure mode.Cannot also cannot by auto-steering collision free by braking collision free if system judges that danger that front detects can detect danger by during autobrake collision free or front, system continues autobrake pattern, ESC system sends accekeration according to system control module in front radar, autobrake is carried out in former track, and " autobrake mark " is shown on instrument display, meanwhile, light brake lamp, navigating mate in prompting car, vehicle rotates forward and carries out autobrake.When system judges that current dangerous is removed, during without the need to proceeding braking or turning to, then proceed in standby mode, continue normally to travel.
In autobrake pattern, if system judges that frontal collisions cannot be avoided completely by self-actuating brake, but after the steering wheel angle that system-computed turns to escape and deceleration/decel, when judging to carry out collision free by the mode of auto-steering, system proceeds to auto-steering pattern.
In auto-steering pattern, if system to occur the faults such as total line dropout, hard error by network monitor during to system, will be shown " collision avoidance system fault " by instrument display display instrument.Can through turning to escape if system judges, the steering wheel angle value that EPS sends according to system control module in front radar and deceleration/decel carry out turning to and braking, simultaneously, instrument display display " auto-steering mark ", light brake lamp, and open the steering indicating light of respective side, remind the navigating mate of passenger and Che other vehicles outer respectively, be about to turn to from car; If system judges that current dangerous is removed, during without the need to proceeding braking or turning to, then proceed in standby mode, continue normally to travel.
The above-mentioned description to embodiment can understand and apply the invention for the ease of those skilled in the art.Person skilled in the art obviously easily can make various amendment to above-described embodiment, and General Principle described herein is applied in other embodiments and need not through performing creative labour.Therefore, the invention is not restricted to embodiment here, those skilled in the art, according to announcement of the present invention, do not depart from improvement that scope makes and amendment all should within protection scope of the present invention.