Apparatus and method for distinguishing ground and obstacles for autonomous mobile vehicle

• US 8,736,820 B2
• Filed: 03/03/2010
• Issued: 05/27/2014
• Est. Priority Date: 03/03/2009
• Status: Active Grant

• Current Assignee: Agency For Defense Development (Government of The Republic of China)
• Original Assignee: Agency For Defense Development (Government of The Republic of China)
• Inventors: Choe, Tok Son, Chae, Jeong Sook, Park, Yong Woon, Kim, Jun
• Primary Examiner(s): Ratcliffe, Luke D
• Assistant Examiner(s): Abraham, Samantha K
• Application Number:
  US13/254,099
• Publication Number:
  US 20110309967A1
• Time in Patent Office: 1,546 Days
• Field of Search: 356/5.01, 356 301- 309, 356/4.01, 356/4.07, 356/5.09, 356/9, 356/625
• US Class Current: 356/5.01
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/875 for determining attitude
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S

Abstract

Disclosed is apparatus for distinguishing between ground and an obstacle for autonomous mobile vehicle, comprising an upper 2D laser radar 1, a lower 2D laser radar 2, and a processing unit 10, the processing unit 10 comprising a distance data receiving part 11, an inclination calculating part 12, a ground and obstacle determining part 13, and a transmitting part. Also disclosed is a method for distinguishing between ground and an obstacle for autonomous mobile vehicle by using the apparatus for distinguishing between ground and an obstacle for autonomous mobile vehicle of claim 1, in which the detected object is determined as an obstacle when the actual inclination (g) of the detected object is larger than the reference inclination, and as ground when the actual inclination (g) of the detected object is smaller than the reference inclination.

Claims

1. Apparatus for distinguishing between ground and an obstacle for autonomous mobile vehicle, which comprises:

an upper 2D laser radar installed on the front upper portion of the autonomous mobile vehicle arranged with predetermined orientation angle θ

₁ with respect to the horizontal base plane of the vehicle,

a lower 2D laser radar installed on the front lower portion of the autonomous mobile vehicle at the location vertically below the upper 2D laser radar with a predetermined vertical distance d_offset and arranged in parallel with the horizontal base plane of the vehicle,

and a processing unit installed on the autonomous mobile vehicle for carrying out predetermined data processing,

the processing unit comprising a distance data receiving part which receives distance data r₁ to the object which is are detected by the upper 2D laser radar, and r₂ to the object which is detected by the lower 2D laser radar,

an inclination calculating part which calculates actual inclination g of the detected object based on the distance data r₁, r₂ received from the distance data receiving part, the orientation angle θ

₁ and the vertical distance d_offset,

wherein g is calculated by the following formula;

g=d_v/d_h×

100

where, d_v=d_offset−

r₁ sin θ

₁, and

d_h=r₁ cos θ

₁−

r₂,

where d_v is the difference in vertical direction between the distance data r₁ to the detected object and distance data r₂ to the detected object, and where d_h is the difference in horizontal direction between the distance data r₁ to the detected object and distance data r₂ to the detected object,

a ground and obstacle determining part determines whether the detected object is ground or an obstacle by comparing the actual inclination of the detected object received from the inclination calculating part and the predetermined reference inclination, and generates a distance data for a virtual 2D laser radar which is assumed to be arranged on the same location as the lower 2D laser radar, and

a transmitting part which transmits the distance data for the virtual 2D laser radar which is assumed to be arranged on the same location as the lower 2D laser radar, generated by the ground and obstacle determining part, to a collision avoiding processing unit of the autonomous mobile vehicle.

2. A method for distinguishing between ground and an obstacle for autonomous mobile vehicle by using the apparatus for distinguishing between ground and an obstacle for autonomous mobile vehicle of claim 1, which comprises:

obtaining distance data in which distance data r₁, r₂ from the upper 2D laser radar and the lower 2D laser radar to the detected object is obtained by using the upper 2D laser radar and the lower 2D laser radar installed on front side of the autonomous mobile vehicle;

calculating inclination in which the actual inclination g of the detected object is calculated by the inclination calculating part of the apparatus for distinguishing between ground and an obstacle for autonomous mobile vehicle by using the distance data r₁, r₂, the orientation angle θ

₁ of the upper 2D laser radar, and the vertical distance d_offset between the upper 2D laser radar and the lower 2D laser radar, wherein g is calculated by the following formula;

g=d_v/d_h×

100

where, d_v=d_offset−

r₁ sin θ

₁, and

d_h=r₁ cos θ

₁−

r₂,

where d_v is the difference in vertical direction between the distance data r₁ to the detected object and distance data r₂ to the detected object, and where d_h is the difference in horizontal direction between the distance data r₁ to the detected object and distance data r₂ to the detected object; and

determining whether the detected object is ground an obstacle in which the ground and obstacle determining part of the processing unit determines the detected object as an obstacle when the actual inclination g of the detected object is larger than the reference inclination, and determines the detected object as ground when the actual inclination g of the detected object is smaller than the reference inclination.

3. The method for distinguishing between ground and an obstacle for autonomous mobile vehicle of claim 2, wherein the minimum value of the obtained distance data r₁, r₂ is stored as a distance data at the angle of the virtual 2D laser radar which is assumed to be arranged on the same location as the lower 2D laser radar when the actual inclination g of the detected object at a certain angle is larger than predetermined reference inclination, and the arbitrary maximum value of the distance that the corresponding 2D laser radar can have is stored as a distance data at the angle of the virtual 2D laser radar which is assumed to be arranged on the same location as the lower 2D laser radar when the actual inclination g of the detected object is smaller than predetermined reference inclination.