US 9,807,925 B2
Robotic mower area coverage system
David A. Johnson, Charlotte, NC (US)
Assigned to Deere & Company, Moline, IL (US)
Filed by David A. Johnson, Charlotte, NC (US)
Filed on Jul. 28, 2010, as Appl. No. 12/845,274.
Prior Publication US 2012/0029755 A1, Feb. 2, 2012
Int. Cl. G05D 1/02 (2006.01); A01D 34/00 (2006.01); G05D 1/00 (2006.01); G06F 19/00 (2011.01)
CPC A01D 34/008 (2013.01) [G05D 1/0219 (2013.01); G05D 1/0265 (2013.01); G05D 2201/0208 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A robotic mower area coverage system, comprising:
a load sensor on the robotic mower signaling a load on a cutting blade motor; a boundary sensor on the robotic mower indicating the distance from the boundary sensor to a boundary wire;
a vehicle control unit on the robotic mower with memory storing data on at least one boundary or area coverage type executed by the robotic mower within a specified preceding time period;
the vehicle control unit providing commands to a pair of wheel motors to drive the robotic mower to provide a selected type of area coverage from a plurality of types of area coverages based on an input signal from the load sensor and determining if the input signal exceeds a predetermined value for uncut grass, wherein the value for uncut grass is determined by grass height, an input from the boundary sensor indicating the distance to the boundary wire, and an input from the memory indicating the coverage type used in a preceding time period, the coverage types including a wide area coverage constituting traveling in a straight line or arc and turning around at a specified angle when an obstacle or the boundary wire is encountered; a local area coverage constituting traveling in an outwardly expanding pattern from an initial position; and a boundary coverage constituting traveling at a specified distance parallel to the boundary wire each area coverage having a different set of steering angles and wheel motor speeds, and changing the commands between the plurality of types of area coverage without discontinuing mowing or mapping the area.