CONTROL APPARATUS FOR AUTONOMOUSLY NAVIGATING UTILITY VEHICLE

• US 20160231749A1
• Filed: 02/04/2016
• Published: 08/11/2016
• Est. Priority Date: 02/10/2015
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Shimamura, Hideaki
• Granted Patent: US 9,874,876 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• CPC Class Codes: G05D 1/0219 ensuring the processing of the whole working surface
• CPC Class Codes: G05D 1/0265 using buried wires

Abstract

In an apparatus for controlling operation of an autonomously navigating utility vehicle travelling about a working area delineated by a boundary wire, the working area including a narrow area and a broad area, there are provided with a magnetic field strength detector, a travel controlling unit controlling the vehicle to turn and travel straight forward every time the vehicle reaches the boundary wire based on the magnetic field strength, and a narrow area discriminating unit discriminating that the vehicle travels in the narrow area when the magnetic field strength is kept to be greater than a threshold value predefined based on a minimum value of the magnetic field strength in the narrow area from a first turn to a second turn of the vehicle, or for a predetermined time period after the first turn.

Claims

1. An apparatus for controlling operation of an autonomously navigating turnable utility vehicle equipped with a body and a prime mover mounted on the body to make the vehicle travel about a working area delineated by a boundary wire laid thereat in order to work autonomously, the working area including a first area and a second area connected to the first area, a distance between mutually facing segments of the boundary wire in the first area being equal to or less than a predetermined value over a predetermined length, a distance between mutually facing segments of the boundary wire in the second area being greater than the predetermined value, comprising:

a magnetic field strength detector installed on the body to detect a magnetic field strength generated by electric current passing through the boundary wire;

a travel controlling unit configured to control the prime mover to make the vehicle turn and travel straight forward every time the vehicle traveling in the working area reaches the boundary wire, based on the magnetic field strength detected by the magnetic field strength detector; and

a first area discriminating unit configured to discriminate that the vehicle travels in the first area when the magnetic field strength detected by the magnetic field strength detector is kept to be greater than a threshold value predefined based on a minimum value of the magnetic field strength in the first area for a first time period from a first turn to a second turn of the vehicle, or when the magnetic field strength detected by the magnetic field strength detector is kept to be greater than the threshold value for a predetermined time period after the first turn.

2. The apparatus according to claim 1, wherein the first area discriminating unit configured to discriminate that the vehicle travels in the first area when the magnetic field strength detected by the magnetic field strength detector is kept to be greater than the threshold value for the first time period and is further kept to be greater than the threshold value for a second time period from the second turn to a third turn of the vehicle.

3. The apparatus according to claim 1, wherein the threshold value is an average value of the minimum value of the magnetic field strength in the first area and a maximum value of the magnetic field strength in the second area.

4. The apparatus according to claim 1, wherein the magnetic field strength detector comprises a first magnetic field strength detector and a second magnetic field strength detector installed spaced apart from each other in a lateral direction of the vehicle, and

the first area discriminating unit is configured to discriminate that the vehicle travels in the first area when a sum of a magnetic field strength detected by the first magnetic field strength detector and a magnetic field strength detected by the second magnetic field strength detector is greater than the threshold value for the first time period, or when a sum of a magnetic field strength detected by the first magnetic field strength detector and a magnetic field strength detected by the second magnetic field strength detector is greater than the threshold value for the predetermined time period.

5. The apparatus according to claim 1, wherein the travel controlling unit is configured to control the prime mover to make the vehicle travel in the first area along the boundary wire based on the magnetic field strength detected by the magnetic field detector, when the first area discriminating unit discriminates that the vehicle travels in the first area.

6. The apparatus according to claim 5, wherein the first area discriminating unit is configured to discriminate whether the vehicle traveling in the first area along the boundary wire reaches an end of the first area based on the magnetic field strength detected by the magnetic field strength detector, and

the travel controlling unit is configured to control the prime mover to make the vehicle travel along the boundary wire in a first direction when the vehicle is discriminated not to reach the end of the first area, and then to make the vehicle travel in a second direction opposite to the first direction with the vehicle shifted laterally by a predetermined amount in the first area when the vehicle is discriminated to reach the end of the first area.

7. The apparatus according to claim 6, further comprising a setting unit configured to set a reference value, wherein

the magnetic field strength detector comprises a first magnetic field strength detector and a second magnetic field strength detector installed spaced apart from each other in a lateral direction of the vehicle,

the travel controlling unit is configured to control the prime mover to make the vehicle travel in the first direction so that a magnetic field strength detected by the first magnetic field strength detector is kept to be the reference value, and to make the vehicle travel in the second direction so that a magnetic field strength detected by the second magnetic field strength detector is kept to be the reference value, and

the first area discriminating unit is configured to discriminate whether the vehicle reaches the end of the first area based on the magnetic field strength detected by the second magnetic field strength detector when the vehicle travels in the first direction, and discriminates whether the vehicle reaches the end of the first area based on the magnetic field strength detected by the first magnetic field detector when the vehicle travels in the second direction.

8. A method for controlling operation of an autonomously navigating turnable utility vehicle equipped with a body and a prime mover mounted on the body to make the vehicle travel about a working area delineated by a boundary wire laid thereat in order to work autonomously, the working area including a first area and a second area connected to the first area, a distance between mutually facing segments of the boundary wire in the first area being equal to or less than a predetermined value over a predetermined length, a distance between mutually facing segments of the boundary wire in the second area being greater than the predetermined value, the vehicle including a magnetic field strength detector installed on the body to detect a magnetic field strength generated by electric current passing through the boundary wire,

comprising the steps of:

controlling the prime mover to make the vehicle turn and travel straight forward every time the vehicle traveling in the working area reaches the boundary wire, based on the magnetic field strength detected by the magnetic field strength detector; and

discriminating that the vehicle travels in the first area when the magnetic field strength detected by the magnetic field strength detector is kept to be greater than a threshold value predefined based on a minimum value of the magnetic field strength in the first area for a first time period from a first turn to a second turn of the vehicle, or when the magnetic field strength detected by the magnetic field strength detector is kept to be greater than the threshold value for a predetermined time period after the first turn.

9. The method according to claim 8, wherein the step of discriminating includes discriminating that the vehicle travels in the first area when the magnetic field strength detected by the magnetic field strength detector is kept to be greater than the threshold value for the first time period and is further kept to be greater than the threshold value for a second time period from the second turn to a third turn of the vehicle.

10. The method according to claim 8, wherein the threshold value is an average value of the minimum value of the magnetic field strength in the first area and a maximum value of the magnetic field strength in the second area.

11. The method according to claim 8, wherein the magnetic field strength detector comprises a first magnetic field strength detector and a second magnetic field strength detector installed spaced apart from each other in a lateral direction of the vehicle, and

the step of discriminating includes discriminating that the vehicle travels in the first area when a sum of a magnetic field strength detected by the first magnetic field strength detector and a magnetic field strength detected by the second magnetic field strength detector is greater than the threshold value for the first time period, or when a sum of a magnetic field strength detected by the first magnetic field strength detector and a magnetic field strength detected by the second magnetic field strength detector is greater than the threshold value for the predetermined time period.

12. The method according to claim 8, wherein the step of controlling includes controlling the prime mover to make the vehicle travel in the first area along the boundary wire based on the magnetic field strength detected by the magnetic field detector, when it is discriminated that the vehicle travels in the first area in the step of discriminating.

13. The method according to claim 12, wherein the step of discriminating includes discriminating whether the vehicle traveling in the first area along the boundary wire reaches an end of the first area based on the magnetic field strength detected by the magnetic field strength detector, and

the step of controlling includes controlling the prime mover to make the vehicle travel along the boundary wire in a first direction when the vehicle is discriminated not to reach the end of the first area, and then to make the vehicle travel in a second direction opposite to the first direction with the vehicle shifted laterally by a predetermined amount in the first area when the vehicle is discriminated to reach the end of the first area.

14. The method according to claim 13, further comprising the step of setting a reference value, wherein

the magnetic field strength detector comprises a first magnetic field strength detector and a second magnetic field strength detector installed spaced apart from each other in a lateral direction of the vehicle,

the step of controlling includes controlling the prime mover to make the vehicle travel in the first direction so that a magnetic field strength detected by the first magnetic field strength detector is kept to be the reference value, and to make the vehicle travel in the second direction so that a magnetic field strength detected by the second magnetic field strength detector is kept to be the reference value, and

the step of discriminating includes discriminating whether the vehicle reaches the end of the first area based on the magnetic field strength detected by the second magnetic field strength detector when the vehicle travels in the first direction, and discriminates whether the vehicle reaches the end of the first area based on the magnetic field strength detected by the first magnetic field detector when the vehicle travels in the second direction.