CN108407803A - A kind of automatic parking control algolithm based on driving experience - Google Patents

Abstract

The invention discloses an automatic parking control algorithm based on driving experience. The method refers to the parking experience of skilled drivers and divides the parking process into six steps: the first step is to drive the car to the longitudinal starting position of parking, That is, the S ₀ section; the second step is to control the parking speed and quickly kill the steering wheel, that is, the S ₁ section; the third step is to increase the vehicle speed to the maximum parking speed after the steering wheel is killed, that is, the S ₂ section; the fourth step When the direction angle of the car reaches a certain angle θ, reduce the speed of the car to the minimum stable speed, and quickly kill the steering wheel in the opposite direction, that is, S ₃ segment; step 5, after the steering wheel is turned to death in the opposite direction, increase the speed of the car to the maximum parking Car speed, that is, S ₄ segment; Step 6 quickly return the steering wheel, that is, S ₅ segment. The automatic parking control algorithm based on driving experience of the present invention has pure geometrical calculation, small amount of calculation, low requirements on hardware equipment, simple and easy process, strong practicability, and is convenient for commercialization.

Description

An Automatic Parking Control Algorithm Based on Driving Experience

technical field

The invention relates to the technical field of automobile intelligent control, in particular to an automatic parking control algorithm based on driving experience.

Background technique

In recent years, with the rapid development of the economy and the continuous improvement of people's living standards, cars have become an important part of people's lives and the main means of transportation. However, with the increase of car ownership, the parking space is getting smaller and smaller, and the driver's operating requirements are getting higher and higher. For inexperienced drivers, it is difficult to easily park the car into a crowded parking space. middle.

At present, in the field of automatic parking technology, there are two main methods of automatic parking control: (1) path planning and path tracking: firstly, the parking drivable area is obtained by means of sensors, and an ideal road is planned in advance in combination with the geometric parameters of the vehicle. Then design various controllers to track the parking trajectory; (2) Algorithm based on empirical knowledge: analyze the empirical knowledge used by the driver when parking, and use advanced control algorithms such as fuzzy control and neural network to carry out Simulation modeling for automated parking. However, these algorithms are computationally complex, require a large amount of calculation, and require high real-time performance of the system, which will increase the cost of algorithm implementation and is not conducive to practical applications. For example, path planning and path tracking algorithms, in the path tracking process, in order to improve the tracking accuracy, real-time feedback from the system is required, and the calculation amount and real-time requirements are high; the algorithm based on empirical knowledge needs to be realized by advanced control algorithm, which is complex and unfavorable to practice. application.

Therefore, in order to solve the above problems, it is necessary to propose an automatic parking control algorithm with a small amount of calculation, good real-time performance, low cost, and practical application.

Contents of the invention

The object of the present invention is to solve the above-mentioned defects in the prior art, and provide an automatic parking control algorithm based on driving experience, which has a small amount of calculation, good real-time performance, low implementation cost, and is convenient for practical application.

The purpose of the present invention can be achieved by taking the following technical solutions:

A kind of automatic parking control algorithm based on driving experience, described automatic parking control algorithm comprises the following steps:

S1. Judging whether the parking space and parking space are too small according to the parking space parameters, parking space and car parameters. formula to get:

In the formula, L _P and W _P are the length and width of the parking space, respectively, L _Pmin and W _Pmin are the length and width of the minimum parking space, H is the width of the road, H _min is the width of the minimum parking space, R _vmin is the minimum turning radius of the car, R _min is the minimum turning radius at the midpoint of the rear axle of the car, L _v and W _v are the length and width of the car respectively, L is the wheelbase of the car, L _f and L _r are the front overhang length and rear overhang length of the car respectively, D _f , D _r , D _i , D _o , D _rb , and D _EB are the safety distances set to ensure parking safety, and D ₂ is the lateral starting position of parking, that is, the distance between the side of the vehicle close to the parking space and the parking space;

S2. Calculate the vehicle direction angle θ when the steering wheel of the vehicle needs to be reversed, and the parking longitudinal starting position D ₁ , wherein the vehicle direction angle θ is calculated according to the following formula:

K ₃ ＝y ₁ +R _min cos(ψ _T )+S ₁ ψ _S -W _P -W _v /2-D ₂ , ψ _T ＝vK ₁ /(ωL), K ₁ ＝-log(cos(δ _fmax )),

δ _fmax = arctan(L/R _vmin ), ψ _S = vK ₂ /(Lδ _fmax ), S ₁ = vt ₁ ;

In the formula, S ₁ is the distance traveled by the car during steering wheel steering, v is the vehicle speed, δ _fmax is the maximum steering angle of the equivalent front wheels, W _P is the width of the parking space, and the longitudinal starting position D ₁ of parking is given by the following formula Calculated to get:

x ₁ =D _r +L _r , y ₁ =R _min -W _v /2-D _o +W _P ;

S3, drive the car to the parking longitudinal starting position _D1 ;

S4. After reaching the parking longitudinal starting position _D1 , park the vehicle at the minimum stable speed _vmin , and simultaneously perform rapid steering at the maximum stable speed of the steering wheel ω _steering ;

S5. When the steering wheel is driven to death, increase the vehicle speed to the maximum parking speed v _max and continue parking;

S6. When the steering angle of the car reaches θ, the steering wheel turns in the opposite direction at the maximum stable speed ω _steering , and at the same time reduces the speed of the car to v _min ;

S7. When the steering wheel is driven to death again, the vehicle speed is raised to the maximum parking speed v _max ;

S8. After the direction angle of the car returns to positive, that is, the car body is parallel to the parking space, the speed of the car is quickly reduced to 0, and the car is stopped;

S9. The car is moving forward at the speed of v _min , and the steering wheel is quickly returned to the center position, and then the car is reversed to the parking position after returning to the center position, and the parking step is completed.

Further, the value range of the parking transverse starting position D ₂ is 0.4-1.0m.

Compared with the prior art, the present invention has the following advantages and effects:

The automatic parking control algorithm proposed by the present invention is obtained by geometric direct derivation, with simple parameters and clear physical meaning; the calculation in the automatic parking control algorithm is completed before the parking starts, and the parking process does not need feedback, and the calculation amount is small and real-time Good performance, low implementation cost, and convenient for practical application.

Description of drawings

Figure 1 is a schematic diagram of automatic parallel parking;

In the figure: Section S ₀ is the process of driving the vehicle to the longitudinal starting position of parking; Section S ₁ is the process of controlling the speed of the vehicle and quickly driving the steering wheel to death; Section S ₂ is the process of raising the vehicle speed to the maximum parking position after driving the steering wheel to death The process of the vehicle speed v _max ; the S ₃ segment is the process in which the steering wheel turns in the opposite direction at the maximum stable speed ω _steering when the steering angle of the car reaches θ; the S ₄ segment is the process of raising the vehicle speed to the maximum parking again after the steering wheel is driven in the opposite direction The process of the vehicle speed v _max ; the S _5th stage is the process of the steering wheel returning to the center quickly;

Fig. 2 is a schematic diagram of a safety gap during parking;

Fig. 3 is the effect drawing of the present invention's control car parking process;

Fig. 4 is the change process of the speed and the front wheel steering angle in the process of controlling the parking of the car in the present invention;

In the figure: v is the vehicle speed, δ _f is the equivalent front wheel steering angle, the relationship with the steering wheel steering angle θ _steering is, θ _steering =i×δ _f , and i is the steering wheel transmission ratio.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example

Please refer to Fig. 1 and Fig. 2, the present embodiment specifically discloses a kind of automatic parking control algorithm based on driving experience, and the specific implementation steps are as follows:

Step S1, judge whether the parking space and parking space are too small according to the parking space parameters, parking space and car parameters, if they are too small, no longer perform automatic parking, otherwise, go to the next step, and the judgment formula can be obtained according to the following formula:

In the formula, L _P and W _P are the length and width of the parking space, respectively, L _Pmin and W _Pmin are the length and width of the minimum parking space, H is the width of the road, H _min is the width of the minimum parking space, R _vmin is the minimum turning radius of the car, R _min is the minimum turning radius at the midpoint of the rear axle of the car, L _v and W _v are the length and width of the car respectively, L is the wheelbase of the car, L _f and L _r are the front overhang length and rear overhang length of the car respectively, D _f , D _r , D _i , Do, D _rb , and D _EB are the safety distances set to ensure parking safety, and D ₂ is the lateral starting position of parking, that is, the distance between the side of the vehicle close to the parking space and the parking space. The value is preferably 0.4-1.0m.

Step S2, calculate the vehicle direction angle θ when the steering wheel of the vehicle needs to be reversed, and the parking longitudinal starting position D ₁ , the vehicle direction angle θ is calculated according to the following formula:

K ₃ ＝y ₁ +R _min cos(ψ _T )+S ₁ ψ _S -W _P -W _v /2-D ₂ , ψ _T ＝vK ₁ /(ωL), K ₁ ＝-log(cos(δ _fmax )),

δ _fmax = arctan(L/R _vmin ), ψ _S = vK ₂ /(Lδ _fmax ),

In the formula, S1 is the distance traveled by the car during steering wheel steering; v is the vehicle speed; δ _fmax is the equivalent front wheel maximum steering angle; W _P is the parking space width;

The parking longitudinal starting position D ₁ can be calculated by the following formula:

x ₁ =D _r +L _r , y ₁ =R _min -W _v /2-D _o +W _P

Step S3, drive the car to the parking longitudinal starting position _D1 ;

Step S4, after reaching the parking longitudinal starting position _D1 , park the vehicle at the minimum stable speed _vmin , and at the same time perform rapid steering at the maximum stable speed of the steering wheel _ωsteering ;

Step S5, when the steering wheel is driven to death, increase the vehicle speed to the maximum parking speed v _max , and continue parking;

Step S6, when the steering angle of the car reaches θ, the steering wheel turns in the opposite direction at the maximum stable speed ω _steering , and at the same time reduces the speed of the car to v _min ;

Step S7, when the steering wheel is driven to death again, increase the vehicle speed to the maximum parking speed v _max ;

Step S8, after the direction angle of the car is back to normal, that is, the car body is parallel to the parking space, the speed of the car is quickly reduced to 0, and the car is stopped;

Step S9 , the car is moving forward at a speed of v _min , and the steering wheel is quickly returned to the center position, and then the car is reversed to the parking position after returning to the center position, and the parking step is completed.

The whole parking process is divided into 6 sections, among which, the first section is S ₀ section, which is the process of driving the vehicle to the longitudinal starting position of parking; the second section is S ₁ section, which is the process of controlling the speed of the vehicle and quickly driving the steering wheel to death ; The third section is _S2 section, which is the process of raising the vehicle speed to the maximum parking speed v _max after the steering wheel is killed; the fourth section is _S3 section, which is the maximum stable speed of the steering wheel ω when the steering angle of the car reaches θ _Steering is the process of turning in the opposite direction; the 5th segment is S ₄ segment, which is the process of raising the vehicle speed to the maximum parking speed v _max again after the steering wheel is turned to death in the opposite direction; the 6th segment is S ₅ segment, which is the process of quickly returning the steering wheel positive process.

In order to verify the effect of the present invention, the automatic parking algorithm of the present invention is used to carry out a parking simulation test. The vehicle parameters used in the simulation are: L _v = 4.155m, W _v = 1.645m, L = 2.405m, L _f = 0.8m, L _r = 0.95m, R _vmin = 4.75m; safety distances D _f , D _r , D _i , Do, D _rb , D _EB are set to 0.2m, and D _r is set to 0.4m; the parking longitudinal starting position D ₂ is set to 0.5m; the minimum stable speed v _min is 2km/h; the maximum parking speed v _max is 5km/h; parking space size L _P ×W _P is 7m×2m; road width H is 4m. The verification comparison results are shown in Figure 3 and Figure 4. It can be seen from Fig. 3 that the algorithm of the present invention can park the vehicle accurately and without collision in the designed parking end area, and can obtain a relatively ideal parking effect. It can be seen from Figure 4 that the vehicle speed changes during parking are consistent with expectations, and at the same time, the parking time is short. This shows that the method of the present invention not only satisfies the parking precision requirement but also satisfies the parking time requirement, the parking method is simple and easy, and the desired purpose of the present invention is achieved.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (2)

1. a kind of automatic parking control algolithm based on driving experience, which is characterized in that the automatic parking control algolithm packet Include the following steps：

S1, judge whether parking stall and parking space are too small according to parking lot parameters, parking space and automobile parameter, if too small Automatic parking is no longer carried out, otherwise, is transferred to next step, the judgement of wherein parking space distance obtains according to the following formula：

In formula, L_PAnd W_PRespectively parking stall is long and wide, L_PminAnd W_PminRespectively minimum parking stall is long and wide, and H is road width, H_min For minimum parking space width, R_vminFor minimum turning radius, R_minFor the min. turning radius at automobile hind axle midpoint, L_vWith W_vThe respectively length and width of automobile, L are the wheelbase of automobile, L_fAnd L_rRespectively the front overhang length of automobile and rear overhang are long, D_f、D_r、D_i、 Do、D_rb、D_EBThe safe distance for security settings of parking for guarantee, D₂It is park lateral initial position namely vehicle close to parking stall one Side is at a distance from parking stall；

S2, it calculates vehicle steering wheel and needs reversely automobile steering angle θ when killing, and longitudinal initial position D that parks₁, wherein Automobile steering angle θ is calculated according to the following formula：

K₃=y₁+R_min cos(ψ_T)+S₁ψ_S-W_P-W_v/2-D₂, ψ_T=vK₁/ (ω L), K₁=-log (cos (δ_{f max})),

δ_{f max}=arctan (L/R_{v min}), ψ_S=vK₂/(Lδ_{f max}),S₁=vt₁；

In formula, S₁For the distance of running car in vehicle steering wheel steering procedure, v is speed, δ_fmaxIt is turned to for equivalent front-wheel maximum Angle, W_PIt is wide for parking stall, wherein park longitudinal initial position D₁It is calculated by following formula：

S3, by running car to longitudinal initial position D that parks₁；

S4, it parks longitudinal initial position D in arrival₁Behind position, with the minimum stabilizing speed v of automobile_minIt parks, while with direction Disk maximum stable rotational speed omega_steeringCarry out fast steering；

S5, after steering wheel is killed, speed is carried to maximum and is parked speed v_max, continue to park；

S6, when the deflection of automobile reaches θ, steering wheel is with maximum stable rotational speed omega_steeringNegative direction steering is carried out, simultaneously will Speed is down to v_min；

S7, after steering wheel is killed again, speed is carried to maximum and is parked speed v_max；

S8, after the direction angular convolution of automobile just after, i.e., body of a motor car is parallel with parking stall, speed is rapidly decreased to 0, and stop；

S9, automobile are with v_minSpeed before returned rapidly just to traveling, and by steering wheel, Hui Zhenghou again by vehicle down to parking position, until This step completion of parking.

2. a kind of automatic parking control algolithm based on driving experience according to claim 1, which is characterized in that described Park lateral initial position D₂Value range be 0.4-1.0m.