CN104176054A - Automobile active anti-collision automatic lane change control system and operating method thereof - Google Patents

Abstract

The invention discloses an automobile active anti-collision automatic lane change control system and an operating method thereof. The system comprises a real-time driving safety state judging module and an automatic lane change control module which are connected with each other; the real-time driving safety state judging module comprises a critical braking distance calculation module and a safety state judging module unit; the automatic lane change control module comprises a lateral dynamics and CarSim vehicle dynamics model establishing module, an expected yaw velocity acquiring module and a design terminal sliding formwork lane change controller module. The method includes two steps of driving safety state judgment and automatic lane change control. The system and method adopt pedestrians in front as the study objects of active anti-collision, whether driving is in the dangerous state or not can be judged by calculating the critical braking distance and corresponded automatic control is performed, the smoothness and operating stability during lane change are guaranteed, and safety of the pedestrians in front is guaranteed.

Description

The automatic lane change control system of a kind of automobile active anti-corrosion and method of work thereof

Technical field

The invention belongs to automobile intelligent control field, relate to vehicle from moving control technology, the particularly automatic lane change control system of a kind of automobile active anti-corrosion and method of work thereof.

Background technology

Along with the development of various countries to the attention of traffic safety and intelligent transportation system, active anti-collision system for car has become the focus of domestic and international research.In existing active anti-collision system for car, main consideration is the vehicle in the place ahead, does not consider the traffic disadvantaged group such as goers outside vehicle.In case of emergency, thereby chaufeur is generally got used to operation brake and is made stop avoiding obstacles rather than turn to and avoiding obstacles by control of vehicle.For these two problems, set up the traffic safety judge module based on pedestrains safety and the automatic lane change control system of vehicle that is intended to protect pedestrian, be the important composition of future automobile active anti-corrosion forewarn system.

Summary of the invention

The problems referred to above that exist for solving prior art, the present invention will design and a kind ofly can carry out in real time traffic safety judgement, and forwardly pedestrian's lower vehicle of realizing in the hole from moving the automatic lane change control system of automobile active anti-corrosion and the method for work thereof of controlling.

For achieving the above object, technical scheme of the present invention is as follows:

The automatic lane change control system of automobile active anti-corrosion, comprises real-time traffic safety condition judgment module and certainly moves control module, and described real-time traffic safety condition judgment module is moved control module with oneself and is connected in series; Described real-time traffic safety condition judgment module comprises braking critical range computing module and safe condition judge module, and the described control module of certainly moving comprises and sets up horizontal dynamic and CarSim Full Vehicle Dynamics model module, asks for expectation yaw velocity module and design terminal sliding formwork changes track control unit module.

A method of work for the automatic lane change control system of automobile active anti-corrosion, comprises the following steps:

A, traffic safety state judgement in real time

In real time traffic safety condition judgment module detects after this front side pedestrian, and Ben Che and the place ahead pedestrian must keep certain safety distance, otherwise will be judged as in the holely, need to control this car.Now collision avoidance scene is done to following simplification:

A, only consider the pedestrian that the place ahead in identical track occurs.

B, consideration traffic safety are main purpose, do not consider arteries of communication efficiency.

C, with the pedestrian's in the place ahead, track speed, with respect to the speed of this car, be approximately 0.

D, only consider the vehicle lane-changing on straight line road and change in process the longitudinal velocity of vehicle constant.

A1, braking critical range are calculated

Braking critical range computing module is set up the minimum safetyspacing model that bicycle Dao Neibenche and the place ahead pedestrian do not bump.When asking for braking critical range, adopt the Safety distance model based on braking procedure, according to Real-time Obtaining, to the relative distance d with the place ahead, track pedestrian and this workshop, judge that whether vehicle is in a safe condition.Pedestrian's speed is approximately static with respect to the speed of vehicle, and therefore must brake critical range is following formula:

In formula, v _x0rate of onset t for this car _rfor time of driver's reaction and brake coordination time sum, value is 0.8～1.0s, t _ifor the time that deceleration/decel increases, get 0.1～0.2s, for coefficient of road adhesion, value be 0.6～0.8, g=9.8m/s ², d ₀the distance of minimum requirements while stopping for this car.

A2, the judgement of traffic safety state

After obtaining braking critical range, safe condition judge module judges the traffic safety state of this car, the following formula of basis for estimation:

d≤d _w (2)

If real-time between Ben Che and pedestrian meets formula (2) apart from d, chaufeur is not still made changing and is travelled or other safety measures, is judged to be driving dangerous, need to do from moving processing this car.Otherwise, to drive a vehicle in a safe condition, vehicle maintains the original state and travels.

B, carry out from moving control

From moving the collision avoidance of control module based on expectation transverse acceleration, change track, adopt terminal sliding mode control method, by the control to yaw angle, make the error of the yaw angle of actual yaw angle and expectation be tending towards 0, realize the tracking of exchange road track, and then realize vehicle intelligent collision pedestrian certainly move control, specifically comprise the following steps:

B1, set up horizontal dynamic and CarSim Full Vehicle Dynamics model

Vehicle dynamic model adopts and comes from the ideal model that Ackermann proposes, and only considers cross motion and the weaving of vehicle, does not relate to the impact of vehicular longitudinal velocity variation and roll motion.The lateral direction of car kinetic model of front-wheel steering is expressed as:

In formula, v _x, v _ywith be respectively vehicular longitudinal velocity, cross velocity and yaw velocity, m is complete vehicle quality, I _zfor the rotor inertia of vehicle around vertical axis, l _fand l _rbe respectively the distance of barycenter to the distance of front axle and barycenter to rear axle, C _f, C _rthe cornering stiffness of tire before and after being respectively, δ is front wheel steering angle.Order

$u_1=\frac{{2C}_f{l}_f}{I_z}\mathrm{\δ}---\left(5\right)$

$u_2=\frac{{2C}_f}{m}\mathrm{\δ}---\left(6\right)$

Formula (3) (4) can be write a Chinese character in simplified form into

B2, ask for the yaw velocity of expectation

Consider the vehicle lane-changing in straight turning road, suppose that in the process of changing, transverse acceleration meets positive inverse taper constraint condition:

$J_d\left(t\right)=\left\{\begin{array}{cc}{J}_{\max }& t_0\≤t\≤t_1\mathrm{or}{t}_4\≤t\≤t_5\\ -J_{\max }& t_2\≤t\≤t_3\\ 0& \mathrm{else}\end{array}\right.---\left(9\right)$

Above formula meets the following conditions:

t ₁-t ₀＝t ₅-t ₄＝Δ ₁

t ₂-t ₁＝t ₄-t ₃＝Δ ₂ (10)

t ₃-t ₂＝2(t ₁-t ₀)＝2Δ ₁

In formula, t ₀wei Huan road zero hour, t ₅wei Huan road finish time, J _maxfor maximum transverse acceleration.To J _d(t) integration must be expected transverse acceleration to expectation transverse acceleration integration obtains cross velocity to cross velocity integration obtains horizontal position y _d(t), Δ ₁and Δ ₂be calculated as follows:

Δ ₁＝a _max/J _max (11)

${\mathrm{\Δ}}_2=-\frac{3}{2}{\mathrm{\Δ}}_1+\frac{1}{2}\sqrt{{{\mathrm{\Δ}}_1}^2+\frac{{4r}_w}{J_{\max }{\mathrm{\Δ}}_1}}---\left(12\right)$

In formula, r _wfor initial track and object track centreline spacing, a _maxmaximum lateral acceleration in Wei Huan road process.Suppose that in the process of changing, the longitudinal velocity of vehicle is constant, yaw angle, the yaw velocity of expectation are following formula:

B3, terminal sliding mode are changed track control unit design

B31, ask for front wheel steering angle controlling quantity

The yaw velocity of vehicle dependence onboard sensor detects, and Vehicular yaw angle is calculated as follows:

Definition yaw angle error is:

Adopt terminal sliding mode control method, design switching function

Wherein: q ₁>0, q ₂>0; k ₁and l ₁for positive odd number, and l ₁>k ₁, to formula (17) differentiate,

By obtaining equivalent control is

Design nonlinear sliding mode is controlled and is

$u_{1\_n}=-\mathrm{\ρs}-{\mathrm{\φs}}^{k_2/l_2}---\left(20\right)$

Wherein, ρ >0, φ >0; k ₂and l ₂for positive odd number, and l ₂>k ₂, get controlling quantity and be

u ₁＝u _{1_equ}+u _{1_n} (21)

For controlling the stability of defective steering stabilizer motion, make v _ymeet

${\stackrel{\·}{v}}_y=-{\∂v}_y---\left(22\right)$

According to horizontal dynamic model, obtain controlling quantity

Finally trying to achieve front wheel steering angle is

$\mathrm{\δ}=\frac{u_1-u_2}{{2C}_f{l}_f/I_z-{2C}_f/m}---\left(24\right)$

B32, stability analysis

Get Lyapunov function to its differentiate,

Push away therefore, when s ≠ 0, illustrate that switching function s=0 has progressive accessibility.

Suppose that when automatic lane change control system arrives switching function s=0 under terminal sliding mode is changed the effect of track control unit, yaw angle error is not 0, by s=0, is obtained because q ₁>0, q ₂>0, k ₁and l ₁for positive odd number, and l ₁/ k ₁<1, by analyzing the differential equation solution know, at sliding mode, yaw angle tracking error in finite time, converge to 0.

By ${\stackrel{\&CenterDot;}{v}}_y=-{\&PartialD;v}_y,\&PartialD;>0,$ As t → ∞, v _y→ 0.

B33, change control

According to the yaw velocity of expectation and actual yaw velocity, terminal sliding mode controller is by making the error of the yaw angle of actual yaw angle and expectation be tending towards 0 to the control of yaw angle, try to achieve control variable front wheel steering angle, CarSim Full Vehicle Dynamics model is controlled, realize the tracking of exchange road track and control, and then reach the object of controlling from moving.

Compared with prior art, the present invention has following beneficial effect:

1, the research object of the present invention using the place ahead pedestrian as active anti-corrosion, and judge that by real-time calculating braking critical range whether driving is in the hole and to automatically controlling with corresponding.

2, the present invention is directed to dangerous situation and designed automatic anticollision control system; the collision avoidance terminal sliding mode controller that changed Trajectory Design based on expectation transverse acceleration; realized certainly moving of the vehicle under dangerous situation; whole change in change procedure change comparatively steady; guarantee good ride comfort and road-holding property in Liao Huan road process, protected the place ahead pedestrian's safety.

3, the present invention adopts the CarSim Full Vehicle Dynamics model of the emulation that CarSim software provides, comprise car body, driving system, brake system, steering swivel system, suspension system and tire etc., this model can simulating vehicle operating condition, reflection system dynamic characteristic also can be taken into account model exactness, makes simulation result better react real scene.

Accompanying drawing explanation

The present invention has accompanying drawing 2 width, wherein:

Fig. 1 is initiatively anticollision control system composition schematic diagram of automobile of the present invention.

Fig. 2 is that automobile active anticollision control system of the present invention is controlled schematic diagram from moving.

The specific embodiment

Below in conjunction with accompanying drawing, the present invention is further described.As shown in Figure 1, the automatic lane change control system of a kind of automobile active anti-corrosion, comprises real-time traffic safety condition judgment module and certainly moves control module, and described real-time traffic safety condition judgment module is moved control module with oneself and is connected in series; Described real-time traffic safety condition judgment module comprises braking critical range module and safe condition judge module, and the described control module of certainly moving comprises that horizontal dynamic and CarSim Full Vehicle Dynamics model module, expectation yaw velocity module and terminal sliding mode change track control unit module.

As shown in Figure 2, a kind of active anti-collision system for car comprises expectation yaw velocity from moving to control, terminal sliding mode controller, CarSim whole vehicle model and from car Sensor section.The yaw velocity W of expectation _dand the interpolation between actual yaw velocity W is as the control inputs of terminal sliding mode controller, front wheel steering angle δ is as the control output of terminal sliding mode controller, the output valve of terminal sliding mode controller is passed to CarSim whole vehicle model, and the input end of terminal sliding mode controller passed to obtained actual yaw velocity W again by self-sensor device.

Claims (2)

1. the automatic lane change control system of automobile active anti-corrosion, is characterized in that: comprise real-time traffic safety condition judgment module and certainly move control module, described real-time traffic safety condition judgment module is moved control module with oneself and is connected in series; Described real-time traffic safety condition judgment module comprises braking critical range computing module and safe condition judge module, and the described control module of certainly moving comprises and sets up horizontal dynamic and CarSim Full Vehicle Dynamics model module, asks for expectation yaw velocity module and design terminal sliding formwork changes track control unit module.

2. a method of work for the automatic lane change control system of automobile active anti-corrosion, is characterized in that: comprise the following steps:

A, traffic safety state judgement in real time

In real time traffic safety condition judgment module detects after this front side pedestrian, and Ben Che and the place ahead pedestrian must keep certain safety distance, otherwise will be judged as in the holely, need to control this car; Now collision avoidance scene is done to following simplification:

A, only consider the pedestrian that the place ahead in identical track occurs;

B, consideration traffic safety are main purpose, do not consider arteries of communication efficiency;

C, with the pedestrian's in the place ahead, track speed, with respect to the speed of this car, be approximately 0;

D, only consider the vehicle lane-changing on straight line road and change in process the longitudinal velocity of vehicle constant;

A1, braking critical range are calculated

Braking critical range computing module is set up the minimum safetyspacing model that bicycle Dao Neibenche and the place ahead pedestrian do not bump; When asking for braking critical range, adopt the Safety distance model based on braking procedure, according to Real-time Obtaining, to the relative distance d with the place ahead, track pedestrian and this workshop, judge that whether vehicle is in a safe condition; Pedestrian's speed is approximately static with respect to the speed of vehicle, and therefore must brake critical range is following formula:

In formula, v _x0rate of onset t for this car _rfor time of driver's reaction and brake coordination time sum, value is 0.8～1.0s, t _ifor the time that deceleration/decel increases, get 0.1～0.2s, for coefficient of road adhesion, value be 0.6～0.8, g=9.8m/s ², d ₀the distance of minimum requirements while stopping for this car;

A2, the judgement of traffic safety state

After obtaining braking critical range, safe condition judge module judges the traffic safety state of this car, the following formula of basis for estimation:

d≤d _w (2)

If real-time between Ben Che and pedestrian meets formula (2) apart from d, chaufeur is not still made changing and is travelled or other safety measures, is judged to be driving dangerous, need to do from moving processing this car; Otherwise, to drive a vehicle in a safe condition, vehicle maintains the original state and travels;

B, carry out from moving control

From moving the collision avoidance of control module based on expectation transverse acceleration, change track, adopt terminal sliding mode control method, by the control to yaw angle, make the error of the yaw angle of actual yaw angle and expectation be tending towards 0, realize the tracking of exchange road track, and then realize vehicle intelligent collision pedestrian certainly move control, specifically comprise the following steps:

B1, set up horizontal dynamic and CarSim Full Vehicle Dynamics model

Vehicle dynamic model adopts and comes from the ideal model that Ackermann proposes, and only considers cross motion and the weaving of vehicle, does not relate to the impact of vehicular longitudinal velocity variation and roll motion; The lateral direction of car kinetic model of front-wheel steering is expressed as:

In formula, v _x, v _ywith be respectively vehicular longitudinal velocity, cross velocity and yaw velocity, m is complete vehicle quality, I _zfor the rotor inertia of vehicle around vertical axis, l _fand l _rbe respectively the distance of barycenter to the distance of front axle and barycenter to rear axle, C _f, C _rthe cornering stiffness of tire before and after being respectively, δ is front wheel steering angle; Order

$u_1=\frac{{2C}_f{l}_f}{I_z}\mathrm{\&delta;}---\left(5\right)$

$u_2=\frac{{2C}_f}{m}\mathrm{\&delta;}---\left(6\right)$

Write a Chinese character in simplified form into formula (3), (4)

B2, ask for the yaw velocity of expectation

Consider the vehicle lane-changing in straight turning road, suppose that in the process of changing, transverse acceleration meets positive inverse taper constraint condition:

$J_d\left(t\right)=\left\{\begin{array}{cc}{J}_{\max }& t_0\&le;t\&le;t_1\mathrm{or}{t}_4\&le;t\&le;t_5\\ -J_{\max }& t_2\&le;t\&le;t_3\\ 0& \mathrm{else}\end{array}\right.---\left(9\right)$

Above formula meets the following conditions:

t ₁-t ₀＝t ₅-t ₄＝Δ ₁

t ₂-t ₁＝t ₄-t ₃＝Δ ₂ (10)

t ₃-t ₂＝2(t ₁-t ₀)＝2Δ ₁

In formula, t ₀wei Huan road zero hour, t ₅wei Huan road finish time, J _maxfor maximum transverse acceleration; To J _d(t) integration must be expected transverse acceleration to expectation transverse acceleration integration obtains cross velocity to cross velocity integration obtains horizontal position y _d(t), Δ ₁and Δ ₂be calculated as follows:

Δ ₁＝a _max/J _max (11)

${\mathrm{\&Delta;}}_2=-\frac{3}{2}{\mathrm{\&Delta;}}_1+\frac{1}{2}\sqrt{{{\mathrm{\&Delta;}}_1}^2+\frac{{4r}_w}{J_{\max }{\mathrm{\&Delta;}}_1}}---\left(12\right)$

In formula, r _wfor initial track and object track centreline spacing, a _maxmaximum lateral acceleration in Wei Huan road process; Suppose that in the process of changing, the longitudinal velocity of vehicle is constant, yaw angle, the yaw velocity of expectation are following formula:

B3, terminal sliding mode are changed track control unit design

B31, ask for front wheel steering angle controlling quantity

The yaw velocity of vehicle dependence onboard sensor detects, and Vehicular yaw angle is calculated as follows:

Definition yaw angle error is:

Adopt terminal sliding mode control method, design switching function

Wherein: q ₁>0, q ₂>0; k ₁and l ₁for positive odd number, and l ₁>k ₁, to formula (17) differentiate,

By obtaining equivalent control is

Design nonlinear sliding mode is controlled and is

$u_{1\_n}=-\mathrm{\&rho;s}-{\mathrm{\&phi;s}}^{k_2/l_2}---\left(20\right)$

Wherein, ρ >0, φ >0; k ₂and l ₂for positive odd number, and l ₂>k ₂, get controlling quantity and be

u ₁＝u _{1_equ}+u _{1_n} (21)

For controlling the stability of defective steering stabilizer motion, make v _ymeet

${\stackrel{\&CenterDot;}{v}}_y=-{\&PartialD;v}_y---\left(22\right)$

According to horizontal dynamic model, obtain controlling quantity

Finally trying to achieve front wheel steering angle is

$\mathrm{\&delta;}=\frac{u_1-u_2}{{2C}_f{l}_f/I_z-{2C}_f/m}---\left(24\right)$

B32, stability analysis

Get Lyapunov function to its differentiate,

Push away therefore, when s ≠ 0, illustrate that switching function s=0 has progressive accessibility;

Suppose that when automatic lane change control system arrives switching function s=0 under terminal sliding mode is changed the effect of track control unit, yaw angle error is not 0, by s=0, is obtained because q ₁>0, q ₂>0, k ₁and l ₁for positive odd number, and l ₁/ k ₁<1, by analyzing the differential equation solution know, at sliding mode, yaw angle tracking error in finite time, converge to 0;

By ${\stackrel{\&CenterDot;}{v}}_y=-{\&PartialD;v}_y,\&PartialD;>0,$ As t → ∞, v _y→ 0;

B33, change control

According to the yaw velocity of expectation and actual yaw velocity, terminal sliding mode controller is by making the error of the yaw angle of actual yaw angle and expectation be tending towards 0 to the control of yaw angle, try to achieve control variable front wheel steering angle, CarSim Full Vehicle Dynamics model is controlled, realize the tracking of exchange road track and control, and then reach the object of controlling from moving.