KR101315488B1 - Method for controlling the steering for automatic parking - Google Patents

Abstract

The present invention relates to a steering control method that can improve the parking alignment during automatic parking, more specifically, the route calculation unit sets the parking target position between the first obstacle vehicle and the second obstacle vehicle, the front And steer the vehicle to follow each of the extended first straight line, second straight line, and third straight line given based on a radius of rotation radius that does not collide with rear obstacle vehicles, wherein the first straight line, the second straight line, and the first straight line 3 Inflection control point for the automatic parking, characterized in that the intersection point of the straight line and the path of the rotation of the car to four inflection points, and calculates the rotational curvature for the steering of the car each time the car passes these inflection points It is about a method.

Description

Steering control method for automatic parking {Method for controlling the steering for automatic parking}

The present invention relates to a steering control method that can improve the parking alignment during automatic parking, more specifically, the route calculation unit sets the parking target position between the first obstacle vehicle and the second obstacle vehicle, the front And steer the vehicle to follow each of the extended first straight line, second straight line, and third straight line given based on a radius of rotation radius that does not collide with rear obstacle vehicles, wherein the first straight line, the second straight line, and the first straight line 3 Inflection control point for the automatic parking, characterized in that the intersection point of the straight line and the path of the rotation of the car to four inflection points, and calculates the rotational curvature for the steering of the car each time the car passes these inflection points It is about a method.

Recently, an automatic parking device that performs automatic parking by assisting the driver's driving ability during parking has been developed and utilized.

This automatic parking device is also called a SPAS (Smart Parking Assist System), and the automatic parking device is installed on the side and front and rear of the vehicle body and uses an ultrasonic sensor to measure the distance to the obstacle, so that the vehicle can be parked. Detect space and position and control steering route of car.

That is, when the car travels the area where the parking space exists, the ultrasonic sensor recognizes the direction of the parking space and calculates the distance information to the parking space, and based on the calculated distance information, the parking target position of the car and the front and After setting the turning safety radius that does not collide with the rear obstacle vehicle, set the steering route to the set parking target position and the parking target position according to the turning safety radius, and then automatically park the vehicle by following the set steering route. Perform steering control for.

However, when the vehicle is actually moved according to the steering path calculated by the automatic parking device, a tracking error regarding the moving position of the vehicle occurs due to the performance limitation of the steering motor, and the vehicle at the steering angle inflection point position is corrected to correct the tracking error. After stopping the engine, the steering angle is recalculated.

A method of automatically parking a vehicle while correcting such a tracking error is known in detail in Korean Patent Application Publication No. 10-2010-31244.

According to the present invention, after calculating the parking target position, the steering for the automatic parking, which considers the speed of the vehicle but follows each extension straight line given based on the radius of rotation radius that does not collide with the obstacle vehicles in the front and the rear, is steering. Provide control method.

According to the present invention for achieving the above technical problem, the path calculation unit sets the parking target position between the first obstacle vehicle and the second obstacle vehicle, the rotation radius angle that does not collide with the obstacle vehicles of the front and rear Steer the vehicle to follow each of the first, second, and third straight lines given as a reference, wherein the point where the first, second, and third straight lines intersect the path on the radius of rotation of the car Four inflection points are specified, and each time the vehicle passes these inflection points, the rotational curvature for steering the vehicle is calculated.

Steering control method for the automatic parking of the present invention having the configuration as described above, considering the speed of the car, after calculating the target position in the parking space, based on the radius of rotation angle that does not collide with the obstacle vehicle in the front and rear By steering the car so as to follow each given straight line, there is an effect that the alignment degree of the automatic parking can be improved without large deviation from the parking target position.

In addition, the automatic parking steering control method of the present invention can be easily applied to the limited capacity memory of the electronic control unit of the vehicle since it is relatively simple.

In addition, the automatic parking steering control method of the present invention can be applied to other categories of control methods for performing control for autonomous steering, for example, a lane departure prevention system or an autonomous vehicle, and thus have wide industrial applicability. Has an advantage.

1 is a block diagram of a steering control device for automatic parking of the present invention;
2 is a view showing a steering path for the present invention automatic parking,
3 is a flowchart of the steering control method of the present invention;
4 is a steering path diagram of step S10 of the steering control method of the present invention;
5A and 5B are a steering path diagram of step S20 of the steering control method of the present invention;
6a, 6b and 6c is a steering path diagram of steps S30 to S50 of the steering control method of the present invention,
7 is a steering path diagram of step S60 of the steering control method of the present invention;
8 is a steering path diagram of step S70 of the steering control method of the present invention;
9 is a steering path diagram of step S80 of the steering control method of the present invention;
10 is a steering path diagram of step S90 and step S100 of the steering control method of the present invention;
11 is a steering path diagram of step S110 of the steering control method of the present invention;
12 is a steering path diagram of step S120 of the steering control method of the present invention.

Hereinafter, with reference to the drawings will be described in detail the configuration of the steering control method for automatic parking of the present invention.

It is to be noted, however, that the disclosed drawings are provided as examples for allowing a person skilled in the art to sufficiently convey the spirit of the present invention. Accordingly, the present invention is not limited to the following drawings, but may be embodied in other forms.

In addition, unless otherwise defined, the terms used in the description of the present invention have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. In the following description and the accompanying drawings, A detailed description of known functions and configurations that may be unnecessarily blurred is omitted.

1 is a block diagram of a steering control device for automatic parking according to the present invention.

The steering control method for automatic parking of the present invention is performed by the illustrated steering control apparatus.

The steering control apparatus of the present invention receives a plurality of obstacle sensor units 10 installed at both sides and front and rear of the vehicle, and a distance measuring signal transmitted from the obstacle sensor unit 10 to the target parking space. A path calculation unit 20 for calculating a steering path for moving the vehicle, and a driving unit 30 for driving the steering system 40 and the braking system 50 of the vehicle according to the steering path calculated by the path calculation unit 20. It is configured to include.

The sensor employed in the obstacle sensor unit 10 in the embodiment of the present invention uses an ultrasonic sensor as known in the art.

The path calculating unit 20 is a control unit for inputting and outputting control signals and data through a known communication network such as an electronic control unit (ECU) and a CAN communication line of a vehicle, and controlling each step of the steering control method of the present invention. The program is stored and executed in the associated memory device.

The driving unit 30 of the embodiment of the present invention employs an electric driving unit such as an electric power steering (EPS) and a motor driven power steering (MDPS) of an automobile.

The steering system 40 and the braking system 50 are mechanical operating modules installed in an automobile to perform steering and braking. The steering system 40 may include a steering wheel, a steering rack, a steering pinion, and the like. The system 50 includes a brake and the like.

2 is a view showing a steering path of the vehicle for the present invention automatic parking.

In the steering control method for automatic parking of the present invention, the path calculation unit 20 sets the parking target position P between the first obstacle vehicle B1 and the second obstacle vehicle B2, and basically the front and The vehicle is driven to follow each of the extended first straight line L1, the second straight line L2, and the third straight line L3, which are given based on the radius of rotation radius which does not collide with the rear obstacle vehicles B1 and B2. Steer.

In addition, four inflection points X1, X2, X3, and X4 designate a point where the first straight line L1, the second straight line L2, and the third straight line L3 intersect the path of the rotation radius of the vehicle. Each time the vehicle passes these inflection points X1, X2, X3, and X4, the rotational curvature for the steering of the vehicle can be calculated to enable more precise and smooth movement compared to the conventional automatic parking method. Hereinafter, the steering control method of the present invention will be described in more detail.

3 is a flowchart of a steering control method for autonomous parking according to the present invention, and FIGS. 4 to 12 are steering path diagrams of a vehicle showing a moving path performed according to the steering control method according to the present invention. When describing the step, it will be described with reference to the steering path diagram shown in the corresponding step.

Referring to Figures 3 and 4, the path calculation unit 20 of the present invention is installed on the side and front and rear of the vehicle body to measure the distance transmitted from the obstacle sensor unit 10, such as an ultrasonic sensor for measuring the distance to the obstacle. The parking target position P at which the vehicle is to be parked is set based on the signal.

In addition, the rotation safety radius does not collide with the front obstacle vehicle B1 based on the distance measurement signal between the front obstacle vehicle B1 and the rear obstacle vehicle B2 transmitted from the obstacle sensor unit 10. A second rotation radius R2 which is a rotation safety radius that does not collide with the first rotation radius R1 and the rear obstacle vehicle B2 is set.

The setting of the parking target position P and the setting of the first rotation radius R1 and the second rotation radius R2 according to the distance measurement signal measured by the obstacle sensor unit 10 are as described above in the related art. It can be carried out according to the known method, so a detailed description thereof will be omitted.

When the parking target position P, the first turning radius R1 and the second turning radius R2 are set as described above, the route calculating unit 20 moves from the current position of the vehicle to the parking target position P. Three linear paths and inflection points on each linear path for setting the path are set (step S 10).

Referring to FIG. 4, the three straight paths are formed at a first straight line L1 which is a straight line component extending in the backward direction of the vehicle while maintaining the angle of the steering angle at the current position of the vehicle, and at the parking target position P. The third straight line L3, which is a straight line segment extending horizontally, the first inflection point X1 at which the vehicle first rotates on the first straight line L1, and the last rotation of the vehicle on the third straight line L3. A second inflection point X4 and a circumferential point moved along the first rotation radius R1 from the first inflection point X1, the second being the point closest to the circumference of the second rotation radius R2. A third inflection point X3 which is a circumferential point moved along the second rotation radius R2 from the inflection point X2 and the fourth inflection point X4 and is closest to the circumference of the first rotation radius R1. ) And a linear component extending by connecting the second inflection point X2 and the third inflection point X3. 2 Set the straight line (L2).

Next, the route calculating section 20 calculates the first vehicle predicted position xd1, which is a distance moving from the current position of the vehicle to the first inflection point X1 (step S20).

5A and 5B, the first vehicle predicted position # d1 may be obtained by the following equation.

(1)

(V: vehicle's moving speed, ㅿ t; travel time, a; acceleration)

As can be seen from Equation 1, the steering control method of the present invention takes into account both the constant speed when the car moves at a constant speed and the deceleration when moving with an acceleration.

Meanwhile, in FIGS. 5A and 5B, Xv denotes an initial point of a vehicle, and Xv * denotes a point of a moved vehicle.

Next, as shown in FIG. 6A, the path calculation unit 20 determines whether the vehicle passes the first inflection point X1 (step S 30), and if the vehicle passes the first inflection point X1, steering of the vehicle. For control, the first curvature r1 from the first inflection point X1 to the second inflection point X2 is calculated according to Equation 2 (step S40).

(2)

r1 = 1 / R1

(R1; first radius of rotation)

In addition, when the first curvature r1 is calculated, as shown in FIGS. 6B and 6C, a distance which is a distance moving from the current position of the vehicle to the second inflection point X2 according to Equation 3 below. One vehicle position ΔΦ 1 is calculated (step S50).

(3)

(Φ ^& ; angular velocity, a; acceleration, R: first radius R1 or second radius R2)

As can be seen in Equation 3, the steering control method of the present invention takes into account both the constant speed when the car moves at a constant speed and the deceleration when moving with an acceleration.

As shown in FIG. 7, the path calculating unit 20 determines whether the vehicle passes the second inflection point X2 (step S60), and if the vehicle passes the second inflection point X2, FIG. 8. As shown in FIG. 6, the curvature from the second inflection point X2 to the third inflection point X3 is maintained for steering control of the vehicle (step S 70).

Next, as shown in FIG. 9, the second vehicle predicted position Δd2, which is the distance that the route calculating unit 20 moves from the current position of the vehicle to the third inflection point X3, is calculated (step S 80). .

And, as shown in Figure 10, the path calculation unit 20 determines whether the car passed through the third inflection point (X3) (step S 90), if the car passed through the third inflection point (X3), the following mathematical According to equation 4, the second curvature r2 from the third inflection point X3 to the fourth inflection point X4 is calculated (step S100).

(Equation 4)

r2 = 1 / R2

(R2; second radius of rotation)

Subsequently, as shown in FIG. 11, the path calculation unit 20 calculates the second vehicle position ΔΦ 2, which is a distance that moves from the current position of the vehicle to the fourth inflection point X4. (Step S 110).

Thereafter, the path calculating unit 20 determines whether the car passes the fourth inflection point X4 (step S 120), and if the car passes the fourth inflection point X4, the car moves to the parking target position P. As shown in FIG. 12, the path calculating unit 20 ends the parking by maintaining the curvature of the vehicle at 0 (step S 130).

As a result of the parking experiment using the automatic parking device and the steering control method of the present invention as described above, the inventors have obtained a very good parking condition in which the horizontal error is 4 cm and the yaw angle error is maintained at 0.14 degrees. .

In the above description, the configuration of the steering control method for automatic parking of the present invention has been described in detail with reference to the accompanying drawings, but the present invention can be variously modified, changed and replaced by those skilled in the art. It should be interpreted as falling within the protection scope of the present invention.

Description of the Related Art [0002]
10; Obstacle Sensor
20; Path calculator
30; The driving unit
40; Steering system
50; Braking system

Claims (3)

Calculates a steering path for moving the vehicle to a target parking space by receiving a plurality of obstacle sensor units 10 installed at both sides and front and rear of the vehicle, and a distance measurement signal transmitted from the obstacle sensor unit 10. Steering control method of the automatic parking device comprising a driving unit 30 for driving the steering system 40 and the braking system 50 of the vehicle according to the path operation unit 20 and the steering path calculated by the path operation unit 20 To
The path computing unit 20 sets the parking target position P between the first obstacle vehicle B1 and the second obstacle vehicle B2 and does not collide with the front and rear obstacle vehicles B1 and B2. Each extended first straight line L1, second straight line L2, and third straight line L3 and four inflection points X1 given on the basis of the first radius of rotation R1 and the second radius of rotation R2. Setting (X2, X3, X4) (step S 10);
Calculating a first vehicle predicted position (dl1), which is a distance that the route calculating unit 20 moves from the current position of the vehicle to the first inflection point (X1) (step S 20);
If the path operation unit 20 determines whether the vehicle has passed the first inflection point X1 (step S 30), and passes the first inflection point X1, the second inflection point X2 is determined from the first inflection point X2. Calculating a first curvature r1 up to (step S40);
When the path calculation unit 20 calculates the first curvature r1, calculating the first vehicle position ΔΦ1, which is a distance moving from the current position of the vehicle to the second inflection point X2 (step S). 50);
If the vehicle has passed the second inflection point X2 (step S 60), the path operation unit 20 determines whether the vehicle has passed the second inflection point X2, and if the vehicle has passed the second inflection point X2, the third inflection point X3 from the second inflection point X2. Maintaining the curvature up to (step S 70);
Calculating a second vehicle predicted position (Δd2), which is a distance that the route calculating unit 20 moves from the current position of the vehicle to the third inflection point (X3) (step S 80);
The path calculation unit 20 determines whether the vehicle passes the third inflection point X3 (step S 90), and if the vehicle passes the third inflection point X3, the fourth inflection point X3 is determined from the third inflection point X3. Calculating a second curvature r2 up to X4) (step S 100);
Calculating a second vehicle position [Delta] [phi] 2, which is the distance that the path calculating section 20 moves from the current position of the vehicle to the fourth inflection point (X4) (step S 110);
Determining whether the vehicle has passed the fourth inflection point X4 (step S 120), and if the vehicle has passed the fourth inflection point X4, ending the parking by maintaining the curvature of the car at zero (Step S 130);
Steering control method for an automatic parking, characterized in that comprises a.
The method of claim 1, wherein the setting of the first straight line L1, the second straight line L2 and the third straight line L3, and the four inflection points X1, X2, X3, and X4 (step S 10) is performed. ,
The first straight line L1 which is a straight line component extending in the backward direction of the vehicle while maintaining the angle of the steering angle at the current position of the vehicle, and the third straight line L3 which is a straight line segment extending horizontally from the parking target position P ), A first inflection point X1 at which the vehicle first rotates on the first straight line L1, a fourth inflection point X4 at which the automobile last rotates on the third straight line L3, and the first inflection point A second inflection point X2 and a fourth inflection point X4 which are circumferential points moved along the first rotation radius R1 from X1 and are closest to the circumference of the second rotation radius R2. A third inflection point X3 and a second inflection point X2 and the second inflection point X2 which are the circumferential points moved along the second rotation radius R2 from the nearest point to the circumference of the first rotation radius R1. It is characterized by setting the second straight line (L2) which is an extended straight line component by connecting three inflection points (X3) Steering control method for automatic parking.
3. The method of claim 2,
The first vehicle predicted position Xd1 and the second vehicle predicted position Xd2 are calculated by Equation 1 below.
The first curvature r1 and the second curvature r2 are respectively calculated by Equations 2 and 4 below,
The first vehicle position ΔΦ 1 and the second vehicle position ΔΦ 2 are calculated by Equation 3 below.

(1)

(V: vehicle's moving speed, ㅿ t; travel time, a; acceleration)

(2)
r1 = 1 / R1
(R1; first radius of rotation)

(3)

(Φ ^& ; angular velocity, a; acceleration, R: first radius R1 or second radius R2)

(4)
r2 = 1 / R2
(R2; second radius of rotation)

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