AUTO-PARKING DEVICE

• US 20090085771A1
• Filed: 09/27/2007
• Published: 04/02/2009
• Est. Priority Date: 09/27/2007
• Status: Active Grant

• Current Assignee: Automotive Research & Testing Center
• Original Assignee: Automotive Research & Testing Center
• Inventors: Lee, Wang-Shuan, Wu, Jui-Hung, Liu, Jing-Fu
• Granted Patent: US 7,737,866 B2
• Time in Patent Office: Days
• US Class Current: 340/932.200
• CPC Class Codes: B62D 15/0285 Parking performed automatically

Abstract

An auto-parking device installed on a vehicle comprises a vehicle status sensing unit for detecting a state of a vehicle, an image acquisition unit for capturing vehicle outside image, a range sensing unit for measuring the space, a processing unit for receiving states of the vehicle from the vehicle status sensing unit, receiving environmental states from the image acquisition unit and range sensing unit, calculating a parking path based on parallel parking or back-in parking and then controlling the vehicle steering, throttle and brake via a driving control unit to automatically park the car into the space as per the planned parking path.

Claims

1. An auto-parking device installed on a vehicle, comprising:

a vehicle status sensing unit for detecting a state of a vehicle,

an image acquisition unit for capturing the vehicle outside image,

a range sensing unit for measuring the parking space,

a processing unit for receiving states of the vehicle from the vehicle status sensing unit, receiving the surrounding information of the vehicle from the image acquisition unit and the range sensing unit, calculating a parking path and then controlling the vehicle steering, throttle and brake to automatically park the car into the space according to the planned parking path, and

wherein in auto-parking, the processing unit calculates the parking path based on parallel parking or back-in parking and then controls the vehicle to move along the planned parking path;

during the parking process, if any obstacles invading the planned path are detected, the auto-parking operation will be suspended and hand over the control priority to the user;

upon elimination of the obstacle, the user can reactivate the device to complete the auto-parking operation.

2. The auto-parking device as claimed in claim 1, wherein in parallel parking, following parameters are used,

a vehicle length L,

a wheelbase l,

a vehicle width W;

a steering ratio N, i.e., the ratio of the steering wheel angle to the front wheel turning angle,

a distance from the rear axle to the vehicle tail c

a maximum steering wheel angle φ

_max,

a length margin of the parking space b₀,

a width margin of the parking spaces b₁,

a width of the parking space D,

a lateral distance between an initial position of the host car and an obstacle in front of the target parking space m,

a longitudinal distance between an initial position of the host car tail and an obstacle in front of the target parking space n;

a formulas for computing the parallel parking path are expressed as follows.

$H=\sqrt{{\left(L-c\right)}^2+2<br><br>R_{\mathrm{min\_out}}<br><br>\left(D-b_1\right)-{\left(D-b_1\right)}^2}+c$ $R_s=\left[l·<br><br>\cot <br><br><br><br>\left(\frac{{\mathrm{\phi <br><br>}}_s}{N}\right)-\frac{W}{2}\right]$ $R_{\mathrm{min\_out}}=\left[l·<br><br>\cot <br><br><br><br>\left(\frac{{\mathrm{\phi <br><br>}}_{\max }}{N}\right)+\frac{W}{2}\right]$ ${\mathrm{\phi <br><br>}}_s=N\times <br><br>{\cot }^{-1}<br><br>\left\{\frac{\left[\frac{{\left(H+n+b_0\right)}^2-2<br><br>R_{\mathrm{min\_out}}<br><br>\left(m+D-b_1\right)+{\left(m+D-b_1\right)}^2}{2<br><br>\left(m+D-b_1\right)}\right]}{l}+\frac{W}{2}\right\}$ $\mathrm{\alpha <br><br>}={\sin }^{-1}<br><br>\left(\frac{H+n+b_0}{R_{\mathrm{min\_out}}+R_s}\right)$ $S_1=R_s\times <br><br>\mathrm{\alpha <br><br>}=R_s\times <br><br>{\sin }^{-1}<br><br>\left(\frac{H+n+b_0}{R_{\mathrm{min\_out}}+R_s}\right)$ $S_2=R_{\mathrm{min\_out}}\times <br><br>\mathrm{\alpha <br><br>}=R_{\mathrm{min\_out}}\times <br><br>{\sin }^{-1}<br><br>\left(\frac{H+n+b_0}{R_{\mathrm{min\_out}}+R_s}\right)$

where H is the length of the parking space needed, R_s is the turning radius of the inner rear wheel for the first turn, R<sub>min—

out</sub> is the minimum turning radius of the outer rear wheel of the vehicle for the second turn, φ

_s is the rotation angle of the steering wheel for the first turn, S₁ is the moving length of the inner rear wheel for the first turn, S₂ is the moving length of the inner rear wheel for the second turn and α

is the included angle between the initial position and the reversing point.

3. The auto-parking device as claimed in claim 1, wherein in back-in parking, following parameters are used,

a vehicle length L,

a wheelbase l,

a vehicle width W,

a steering ratio N,i.e., the ratio of the steering wheel angle to the front wheel turning angle,

a distance from the rear axle to the vehicle tail c,

a maximum steering wheel angle φ

_max,

a length margin of the parking space b₀,

a width margin of the parking spaces b₁,

a width of the parking space is D,

a length of the parking space is Z,

a lateral distance between an initial position of the host car and an obstacle in front of the target parking space m,

a longitudinal distance between an initial position of the host car tail and an obstacle in front of the target parking space n.

the formulas for computing the back-in parking path are expressed as follows.

$R_{\mathrm{min\_in}}=\left[l·<br><br>\cot <br><br><br><br>\left(\frac{{\mathrm{\phi <br><br>}}_{\max }}{N}\right)-\frac{W}{2}\right]$ $R_{\mathrm{min\_out}}=\left[l·<br><br>\cot <br><br><br><br>\left(\frac{{\mathrm{\phi <br><br>}}_{\max }}{N}\right)+\frac{W}{2}\right]$ $S_1=R_{\mathrm{min\_in}}\times <br><br>\frac{\mathrm{\pi <br><br>}}{2}$ $S_2=Z-\left(R_{\mathrm{min\_in}}-m\right)-c-b_2$

where R<sub>min—

in</sub> is the minimum turning radius of the inner rear wheel of the vehicle, R<sub>min—

out</sub> is the minimum turning radius of the outer rear wheel of the vehicle, S₁ is the moving length of the inner rear wheel before the reversing point is, and S₂ is the moving length of the inner rear wheel after the reversing point.

4. The auto-parking device as claimed in claim 1, wherein the processing unit is connected to a display unit.

5. The auto-parking device as claimed in claim 1, wherein the processing unit is connected to an adjusting unit for setting and adjustment.

6. The auto-parking device as claimed in claim 1, wherein the vehicle status sensing unit includes a reverse sensing unit, an angle sensing unit and a displacement sensing unit;

the reverse sensing unit is connected to the vehicle shift mechanism to detect whether the shift is switched to reverse gear;

the angle sensing unit is connected to the vehicle steering mechanism to detect the steering angle of a vehicle; and

the displacement sensing unit is connected with the vehicle speed so as to calculate the moving distance of a vehicle.

7. The auto-parking device as claimed in claim 1, wherein the processing unit controls the vehicle steering, throttle and brake via a driving control unit to automatically park the car into the space according to the planned parking path.

8. The auto-parking device as claimed in claim 2, wherein the processing unit detects whether the length of the parking space measured achieves a required minimum value of H+2b₀ for performing the auto-parking.

9. The auto-parking device as claimed in claim 3, wherein the processing unit detects whether the parking space is greater than a required minimum value of W+2b₁.

10. The auto-parking device as claimed in claim 3, wherein the processing determines whether the measured value m is greater than a required minimum value of R_min—

_in−

√

{square root over (R<sub>min—

in</sub>²−

(R<sub>min—

out</sub>−

W−

b¹)²)}+b₀ and whether n is equal to the value of R<sub>min—

out</sub>−

W−

c−

b₁; and

only if these conditions are conformed completely, the auto-parking maneuver can be performed.

11. The auto-parking device as claimed in claim 4, wherein the processing unit calculates a predicted parking spot and superimposed onto the image of actual parking vacancy, and then shown on the display unit;

the position of the predicted parking spot can be fine-adjusted through the display unit or the adjusting unit.

12. The auto-parking device as claimed in claim 11, wherein the display unit is a touch panel for setting and adjustment.