Control apparatus for autonomously navigating utility vehicle

• US 9,939,812 B2
• Filed: 03/24/2016
• Issued: 04/10/2018
• Est. Priority Date: 03/27/2015
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Yamamura, Makoto
• Primary Examiner(s): Butler, Rodney A
• Assistant Examiner(s): Weber, Tamara L
• Application Number:
  US15/080,102
• Publication Number:
  US 20160282867A1
• Time in Patent Office: 747 Days
• Field of Search: None
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• CPC Class Codes: G05D 1/0088 characterized by the autonomous decision making process, e.g. artificial intelligence, predefined behaviours using knowledge based models G06N5/00
• CPC Class Codes: G05D 1/0265 using buried wires
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS

Abstract

An apparatus for controlling operation of an autonomously navigating utility vehicle equipped with a prime mover to travel about a working area delineated by a boundary line, there are provided with a map generating unit that that generates a working area map comprised of an array of a plurality of cells, a memory unit that counts and memorizes a number of times the vehicle passes over each of the cells based on the detected vehicle position; a target cell setting unit that selects one of the cells based on the memorized counted number and sets the selected one as a target cell; and a travel controlling unit that controls operation of the prime mover to make the vehicle travel about the working area until the vehicle has reached the boundary line, and make the vehicle turn toward the target cell and then travel straight forward when the vehicle has reached the boundary line.

Claims

1. An apparatus for controlling operation of an autonomously navigating utility vehicle equipped with a body and a prime mover mounted on the body to travel about a working area delineated by a boundary wire in order to perform work autonomously, the apparatus comprising:

magnetic sensors installed spaced apart from each other in a lateral direction of the body of the vehicle, wherein each of the magnetic sensors detects a magnetic field strength generated by electric current passing through the boundary wire;

a position sensor that determines a position of the vehicle; and

an electronic control unit having a CPU and a memory;

the CPU controls the vehicle to circuit along the boundary wire in trace mode based on output from at least one of the magnetic sensors, determines a boundary line for the working area based on output from the position sensor when the vehicle is driven in the trace mode, generates a map of the working area comprised of an array of cells, and stores a count number in the memory for each of the cells indicating a number of times the vehicle passes over each of the cells in work mode;

the CPU, in the work mode, controls the vehicle to travel in the working area, acquires position data of the vehicle based on the output of the position sensor, identifies each of the cells on the map over which the vehicle passes in the work mode based on the position data, and updates the count number in the memory for individual ones of the cells each time the vehicle passes over the individual ones of the cells;

the CPU, in the work mode, determines when the vehicle reaches the boundary wire based on the output of the magnetic sensors, controls the vehicle to stop when reaching the boundary wire, calculates an average of count numbers for the cells in the map, determines whether at least one of the cells has a count number smaller than the average by at least a predetermined value, controls the vehicle to turn toward the inside of the working area at a random angle when none of the cells have a count number that is smaller than the average by at least the predetermined value, selects a target cell from the at least one of the cells when the at least one of the cells has a count number smaller than the average by at least the predetermined value, and controls the vehicle to turn toward a target direction directed at the target cell.

2. The apparatus according to claim 1, wherein:

the CPU calculates the average by dividing a sum of the count numbers for the cells by a total number of the cells.

3. The apparatus according to claim 1, wherein:

the CPU increments the count number in the memory by a value of one for the individual ones of the cells each time the vehicle passes over the individual ones of the cells.

4. The apparatus according to claim 1, wherein:

the CPU selects the target cell having a count number that is smallest among the at least one of the cells.

5. The apparatus according to claim 4, wherein:

when a set of the cells have a count number that is smallest among the cells, the CPU excludes the cells of the set having the boundary line between itself and the vehicle, and selects the target cell from remaining ones of the set.

6. A method for controlling operation of an autonomously navigating utility vehicle equipped with a body and a prime mover mounted on the body to travel about a working area delineated by a boundary wire in order to perform work autonomously, the method comprising:

controlling the vehicle to circuit along the boundary wire in trace mode based on output from at least one of a pair of magnetic sensors installed spaced apart from each other in a lateral direction of the body of the vehicle, wherein each of the magnetic sensors detects a magnetic field strength generated by electric current passing through the boundary wire;

determining a boundary line for the working area based on output from a position sensor when the vehicle is driven in the trace mode;

generating a map of the working area comprised of an array of cells;

storing a count number in memory for each of the cells indicating a number of times the vehicle passes over each of the cells in work mode;

controlling, in the work mode, the vehicle to travel in the working area;

acquiring, in the work mode, position data of the vehicle based on the output of the position sensor;

identifying each of the cells on the map over which the vehicle passes in the work mode based on the position data;

updating the count number in the memory for individual ones of the cells each time the vehicle passes over the individual ones of the cells;

determining, in the work mode, when the vehicle reaches the boundary wire based on the output of the magnetic sensors

controlling the vehicle to stop when reaching the boundary wire;

calculating an average of count numbers for the cells in the map;

determining whether at least one of the cells has a count number smaller than the average by at least a predetermined value;

when none of the cells have a count number that is smaller than the average by at least the predetermined value, controlling the vehicle to turn toward the inside of the working area at a random angle;

when the at least one of the cells has a count number smaller than the average by at least the predetermined value, selecting a target cell from the at least one of the cells, and controlling the vehicle to turn toward a target direction directed at the target cell.

7. The method according to claim 6, wherein calculating an average of count numbers comprises:

calculating the average by dividing a sum of the count numbers for the cells by a total number of the cells.

8. The method according to claim 6, wherein updating the count number in the memory comprises:

incrementing the count number in the memory by a value of one for the individual ones of the cells each time the vehicle passes over the individual ones of the cells.

9. The method according to claim 6, wherein selecting a target cell from the at least one of the cells comprises:

selecting the target cell having a count number that is smallest among the at least one of the cells.

10. The method according to claim 9, wherein selecting a target cell from the at least one of the cells comprises:

when a set of the cells have a count number that is smallest among the cells, excluding the cells of the set having the boundary line between itself and the vehicle, and selecting the target cell from remaining ones of the set.