Self-propelled mower having enhanced maneuverability

• US 7,024,843 B2
• Filed: 03/23/2004
• Issued: 04/11/2006
• Est. Priority Date: 11/21/2003
• Status: Expired due to Fees

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Hunt, Kenneth Edward, Holm, David Roy
• Primary Examiner(s): FABIAN-KOVACS, ARPAD
• Application Number:
  US10/808,237
• Publication Number:
  US 20050108998A1
• Time in Patent Office: 749 Days
• Field of Search: 56/102.R, 56/102.A, 56/105, 56/119, 56/147, 56D/IG.2, 56D/IG.7, 56D/IG.15, 701/50
• US Class Current: 56/6
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• CPC Class Codes: A01D 34/66 with two or more cutters
• CPC Class Codes: B62D 5/0418 Electric motor acting on road wheel carriers
• CPC Class Codes: B62D 7/026 characterised by comprising more than one bogie, e.g. situated in more than one plane transversal to the longitudinal centre line of the vehicle
• CPC Class Codes: B62D 7/1509 with different steering modes, e.g. crab-steering, or steering specially adapted for reversing of the vehicle
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00

Abstract

A method for operating a mower comprises defining a reference axis of rotation at a desired point along a path segment of the mower. A controller orients wheels of the mower generally tangentially to a circular region about the reference axis. A drive motor applies rotational mechanical energy to one or more of the wheels to rotate the mower by a desired angular amount about the reference axis.

Claims

1. A method for operating a mower, the method comprising

defining a reference axis of rotation at a desired point along a path segment of the mower with a mowing deck comprising three generally semi-circular sections having corresponding centerpoints that are substantially equidistant to a geometric center point of the mower;

orienting the wheels generally tangentially to a circular region about the reference axis of rotation, each of the wheels located within a corresponding indentation in the mowing deck; and

applying rotational mechanical energy to one or more of the wheels to rotate the mower by a desired angular amount about the reference axis.

2. The method according to claim 1 further comprising:

stopping the application of rotational energy to achieve rotation by the desired angular amount; and

reorienting the wheels of the mower toward a next direction of travel in accordance with a next desired path segment.

3. The method according to claim 1 wherein the desired point represents a position where the mower is capable of servicing the work area without the mower or one or more of its cutting blades extending beyond the work area at all or by more than an allowable tolerance.

4. The method according to claim 1 wherein the applying rotational mechanical energy comprises rotating the mower to orient a critical point to face toward a concave boundary to be trimmed.

5. The method according to claim 1 wherein the applying rotational mechanical energy comprises rotating the mower to orient a critical point to face toward a convex boundary to be trimmed.

6. The method according to claim 1 further comprising:

coasting the mower in a linear mode while applying the rotational mechanical energy to one or more wheels.

7. The method according to claim 1 further comprising:

pausing movement of the mower in a linear mode while applying the rotational mechanical energy to one or more wheels.

8. The method according to claim 1 further comprising:

coasting the mower in an arc mode while applying the rotational mechanical energy to one or more wheels.

9. The method according to claim 1 further comprising:

pausing movement of the mower in an arc mode while applying the rotational mechanical energy to one or more wheels.

10. The method according to claim 1 wherein each generally semi-circular section contains a generally vertical shaft coupled to a cutting blade, a periphery of the mowing deck having the indentations as open regions between adjacent semi-circular sections.

11. The method according to claim 1 wherein the wheels are free from mechanical interference to rotate with respect to a steered axis over a range of at least ninety degrees.

12. A method of executing a path plan, the method comprising:

moving a mower having three steerable wheels along a first row of a path plan in a first direction;

defining an end point of the first row as a first axis of rotation;

rotating the mower by approximately ninety degrees with respect to the first axis of rotation generally coincident with a center point, of the mower, associated with substantially uniform radii to the three steerable wheels;

moving along a transverse section that is substantially orthogonal to the first row;

defining an end point of the transverse section as a second axis of rotation;

rotating the mower by approximately ninety degrees with respect to the second axis of rotation generally coincident with the center point, of the mower, associated with substantially uniform radii to the three steerable wheels; and

moving the mower along a second generally linear row in a generally opposite direction with respect to the first direction.

13. The method according to claim 12 wherein the rotating with respect to at least one of the first axis of rotation and the second axis of rotation comprises the following steps:

defining a reference axis of rotation, as at least one of the first axis of rotation and the second axis of rotation, at a desired point along a path segment of the mower;

orienting the wheels generally tangentially to a circular region about the reference axis of rotation; and

applying rotational mechanical energy to one or more of the wheels to rotate the mower by a desired angular amount.

14. The method according to claim 13 further comprising:

stopping the application of rotational energy to achieve rotation by the desired angular amount; and

reorienting the wheels of the mower toward a next direction of a next desired path segment.

15. The method according to claim 12 wherein the desired point represents a position where the mower is capable of servicing the work area without the mower or one or more of its cutting blades extending beyond the work area at all or by more than an allowable tolerance.

16. The method according to claim 12 wherein the first row and the second row comprise generally linear rows.

17. The method according to claim 12 further comprising selecting an end point of the first row such that an outer cutting edge of a cutting blade of the mower is generally coextensive with a boundary or perimeter of the work area.

18. The method according to claim 12 further comprising selecting a length of the transverse section to provide a proper generally parallel spacing between the first row and the second row, in which the swath or cut width of the mower is permitted to overlap.

19. The method according to claim 12 wherein a centerline of each row is generally spaced apart by less than one-half of the swath or cut width of the mower to minimize overlap and reduce energy consumption of the mower.

20. A method of executing a path plan, the method comprising:

moving a mower along a first row of a path plan in a first direction, the mower comprising three steerable wheel assemblies driven by at least one drive motor mounted on a respective one of the wheel assemblies;

defining an end point of the first row;

rotating a steered direction of wheels of the mower with respect to a steered axis by approximately ninety degrees when the mower is at or near the end point;

moving along a transverse section that is substantially orthogonal to the first row;

defining an end point of the transverse section;

rotating a steered direction of wheels of the mower by approximately ninety degrees when the mower is at or near the end point; and

moving the mower along a second generally linear row in a generally opposite direction with respect to the first direction.