Obstacle detection apparatus and method for detecting obstacle

• US 20100220550A1
• Filed: 02/02/2010
• Published: 09/02/2010
• Est. Priority Date: 02/27/2009
• Status: Active Grant

• Current Assignee: DENSO Corporation, Nippon Soken, Inc.
• Original Assignee: DENSO Corporation, Nippon Soken, Inc.
• Inventors: Matsuoka, Hisanaga, Matsuura, Mitsuyasu, Akiyama, Keiko, Okuda, Yasuyuki, Ariyoshi, Hiromi
• Granted Patent: US 8,503,265 B2
• Time in Patent Office: Days
• US Class Current: 367/93
• CPC Class Codes: G01S 15/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S15/46
• CPC Class Codes: G01S 15/46 Indirect determination of position data
• CPC Class Codes: G01S 15/87 Combinations of sonar systems
• CPC Class Codes: G01S 15/931 of land vehicles
• CPC Class Codes: G01S 2015/939 vertical stacking of sensors, e.g. to enable obstacle height determination
• CPC Class Codes: G01S 7/5273 using digital techniques
• CPC Class Codes: G01S 7/539 using analysis of echo signal for target characterisation; Target signature; Target cross-section

Abstract

A transmission and reception device is located at a predetermined height on a movable object and directed toward an outside. The transmission and reception device includes a transmission unit for repeatedly transmitting sensing waves at a predetermined interval and a reception unit for receiving reflective waves of the sensing waves from a detected object. A peak value detecting unit detects peak values of the received reflective waves and stores the detected peak values. A difference arithmetic unit calculates a difference in the detected peak values with movement of the movable object closer to the detected object. An object determination unit determines the detected object to be a near-road-surface obstacle, which is close to a road surface, when the difference is a negative value. The object determination unit determines the detected object to be an other obstacle than the near-road-surface obstacle when the difference is a positive value.

Claims

1. An obstacle detection apparatus comprising:

a transmission and reception device located at a predetermined height on a movable object and directed toward an outside, the transmission and reception device including

i) a transmission unit configured to repeatedly transmit sensing waves at a predetermined interval and

ii) a reception unit configured to receive reflective waves of the sensing waves from a detected object in a detection area;

a peak value detecting unit configured to detect peak values of the reflective waves received by the reception unit and configured to store the detected peak values;

a difference arithmetic unit configured to calculate a difference in the peak values detected by the peak value detecting unit with movement of the movable object closer to the detected object; and

an object determination unit configured to

i) determine a kind of the detected object to be a near-road-surface obstacle, which exists at a position close to a road surface, when the difference in the peak values calculated by the difference arithmetic unit is a negative value, and

ii) determine the kind of the detected object to be an other obstacle, which exists at a position higher than the position close to the road surface, when the difference in the peak values calculated by the difference arithmetic unit is a positive value.

2. The obstacle detection apparatus according to claim 1, wherein the object determination unit is configured to determine the kind of the detected object to be the near-road-surface obstacle at a position where the difference becomes a negative value due to that the detected object comes to an outside of the detection area with movement of the movable object closer to the detected object.

3. The obstacle detection apparatus according to claim 1, wherein the transmission and reception device is located at a position higher than a bumper of the movable object.

4. The obstacle detection apparatus according to claim 1, further comprising:

a linear distance arithmetic unit configured to detect a time period between a time point, at which the transmission unit transmits the sensing wave, and a time point, at which the reception unit receives the reflective waves from the detected object, and configured to calculate a linear distance from the detected object based on the detected time period and a speed of the sensing wave; and

a horizontal distance arithmetic unit configured to calculate a horizontal distance from the near-road-surface obstacle based on the linear distance detected by the linear distance arithmetic unit and the height of the transmission and reception device when the object determination unit determines the detected object to be the near-road-surface obstacle.

5. The obstacle detection apparatus according to claim 4, further comprising:

a horizontal direction reception unit located at a height substantially equivalent to the height of the reception unit and at a distance from the reception unit to receive reflective waves of the sensing waves from the detected object in the detection area;

a horizontal direction detecting unit configured to detect a phase difference between a signal of one of the reflective waves received by the reception unit and a signal of corresponding one of the reflective waves received by the horizontal direction reception unit and configured to detect a horizontal direction, in which the detected object exists, the horizontal direction being at an inclination angle relative to a detection reference direction; and

a vertical direction detecting unit configured to calculate a vertical direction, in which the near-road-surface obstacle exists, based on the linear distance detected by the linear distance arithmetic unit and the height of the transmission and reception device,

wherein the horizontal direction detecting unit includes a horizontal direction correction unit configured to correct the horizontal direction based on the vertical direction calculated by the vertical direction detecting unit when the object determination unit determines the detected object to be the near-road-surface obstacle on detection of the horizontal direction.

6. The obstacle detection apparatus according to claim 1;

wherein the transmission and reception device further includes;

i) a low position reception unit located at a position lower than the transmission and reception device in the movable object and directed toward an outside, the low position reception unit being configured to receive reflective waves of the sensing waves from the detected object in the detection area; and

ii) a distance arithmetic unit configured to detect a time period between a time point of transmission of the sensing wave and a time point, at which the low position reception unit receives the reflective waves from the detected object, and configured to calculate a distance from the detected object based on the detected time period and a speed of the sensing wave,

wherein the transmission and reception device employs the distance calculated by the distance calculation unit as a distance from the detected object when the object determination unit determines the detected object to be the near-road-surface obstacle.

7. The obstacle detection apparatus according to claim 1, further comprising:

an information unit configured to perform an information operation differently according to the kind of the detected object determined by the object determination unit.

8. The obstacle detection apparatus according to claim 7, wherein the information unit is configured to output information sound differently according to the kind of the detected object.

9. The obstacle detection apparatus according to claim 7, wherein the information unit includes an indication portion configured to perform indication differently according to the kind of the detected object.

10. The obstacle detection apparatus according to claim 1, wherein the transmission unit of the transmission and reception device is configured to transmit an ultrasonic wave signal as the sensing wave.

11. The obstacle detection apparatus according to claim 1, wherein the difference is a value between one of the peak values and an other of the peak values, which is subsequent to the one of the peak values.

12. A method for detecting an obstacle, the method comprising:

repeatedly transmitting sensing waves at a predetermined interval from a predetermined height on a movable object toward an outside of the movable object;

receiving reflective waves of the sensing waves at the predetermined height on the movable object from a detected object in a detection area;

detecting peak values of the received reflective waves;

storing the detected peak values;

calculating a difference in the stored detected peak values with movement of the movable object closer to the detected object;

determining a kind the detected object to be a near-road-surface obstacle, which exists at a position close to a road surface, when the calculated difference in the peak values is a negative value; and

determining the kind of the detected object to be an other obstacle, which exists at a position higher than the position close to the road surface, when the calculated difference in the peak values is a positive value.

13. The method according to claim 12, wherein the difference is a value between one of the peak values and an other of the peak values, which is subsequent to the one of the peak values.