AUTOMATIC PARKING SYSTEM FOR VEHICLE

• US 20090157260A1
• Filed: 12/02/2008
• Published: 06/18/2009
• Est. Priority Date: 12/12/2007
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Lee, Jong Ho
• Granted Patent: US 8,229,645 B2
• Time in Patent Office: Days
• US Class Current: 701/41
• CPC Class Codes: B62D 15/0285 Parking performed automatically

Abstract

Disclosed herein is an automatic parking system for a vehicle. The automatic parking system employs a method of generating a parking trajectory in consideration of the operational performance of a steering motor connected to the steering wheel of a vehicle, thus guiding a vehicle through smooth parking and reducing an error between an ideal parking trajectory and an actual parking trajectory.

Claims

1. An automatic parking system for a vehicle, comprising:

one or more sensor units for detecting location information of a vehicle;

a control unit for calculating steering angles by generating a trajectory equation and using the location information from the sensor unit or units and, generating control command signals on the basis of the calculation; and

a driving unit comprising a motor unit configured to perform forward rotation or reverse rotation at a predetermined angle or angles in response to the command signals from the control unit, and a gear unit engaged with a shaft of the motor unit at a predetermined gear ratio and configured to generate a predetermined rotation moment;

wherein the control unit generates the trajectory equation with a plurality of polynomial curves.

2. The automatic parking system as set forth in claim 1, wherein the plurality of polynomial curves is expressed by the following equation:

$P<br><br>\left(u\right)=\underset{k=0}{\overset{n}{\sum <br><br>}}<br><br>P_k<br><br>{\mathrm{Ploycurve}}_{k,n}<br><br>\left(u\right),0\le <br><br>u\le <br><br>1,n=4$

where

${\mathrm{Polycurve}}_{k,n}<br><br>\left(u\right)=\frac{n!}{k!<br><br>\left(n-k\right)!}<br><br>{u^k<br><br>\left(1-u\right)}^{n-k},$

k is an index of a control point for a single polynomial curve, n is a maximum number of control points, and p_k is the control point.

3. The automatic parking system as set forth in claim 1, wherein control points of a first polynomial curve are symmetrical to corresponding control points, respectively, of second polynomial curve adjacent to the first polynomial curve with respect to a vertical line passing a control point common in the two adjacent polynomial curves.

4. The automatic parking system as set forth in claim 2, wherein the plurality of polynomial curves comprises a first polynomial curve that comprises control points for converting neutral steering angles into a constant steering angle for a minimum turning radius and a second polynomial curve that comprises control points for performing conversion into steering angles for a turning radius such as that of an arc.

5. The automatic parking system as set forth in claim 3, wherein:

the control points constituting the first polynomial curve are arranged along a rectilinear line at regular intervals in order to form the neutral steering angles; and

the following coordinate relation equation is applied to the control points constituting the second polynomial curve in order to form the steering angle for a turning radius such as that of an arc;

$P_3<br><br>\left(x<br><br><br><br>0,y<br><br><br><br>0\right)$ $P_2<br><br>\left(x<br><br><br><br>1,y<br><br><br><br>1\right)=\left(\frac{\left(4-\cos <br><br><br><br>{\mathrm{\theta <br><br>}}_1\right)}{3}<br><br>R,\frac{\left(1-\cos <br><br><br><br>{\mathrm{\theta <br><br>}}_1\right)<br><br>\left(\cos <br><br><br><br>{\mathrm{\theta <br><br>}}_1-3\right)}{3<br><br><br><br>\sin <br><br><br><br>{\mathrm{\theta <br><br>}}_1}<br><br>R\right)$ $P_1<br><br>\left(x<br><br><br><br>2,y<br><br><br><br>2\right)=\left(x<br><br><br><br>1,-y<br><br><br><br>1\right)$ $P_0<br><br>\left(x<br><br><br><br>3,y<br><br><br><br>3\right)=\left(x<br><br><br><br>0,-y<br><br><br><br>0\right)$

where R is a turning radius, and θ

₁ is an angular value that is obtained by equally dividing an angle between P₃ and P₀ on an arc that has turning radius R and passes through P₃ and P₀.

6. The automatic parking system as set forth in claim 1, wherein the sensor units are visual sensors or sonic sensors.