1. An autonomous work vehicle travel system that manages autonomous
travel of a work vehicle that travels while working in a work site, the system
comprising:
a satellite positioning module that outputs positioning data indicating a vehicle position of the work vehicle;
an area setting unit that sets an area to be worked in the work site;
a route managing unit that calculates a travel route element set, the travel route element set being an aggregate of multiple travel route elements constituting a travel route covering the area to be worked, and stores the travel route element set so as to be capable of readout;
a route element selecting unit that selects a next travel route element, which is to be traveled, sequentially from the travel route element set; and
an autonomous travel controlling unit that causes the work vehicle to travel autonomously on the basis of the next travel route element and the vehicle position.
2. The autonomous work vehicle travel system according to claim 1,
wherein the area setting unit sets an area on an outer peripheral side
of the work site circled by the work vehicle as an outer peripheral area, and sets the inner side of the outer peripheral area as the area to be worked.
3. The autonomous work vehicle travel system according to claim 1 or 2,
further comprising:
a work state evaluating unit that outputs state information found by evaluating a work environment of the work vehicle,
wherein the route element selecting unit selects the next travel route element from the travel route element set on the basis of the vehicle position and the state information.
4. The autonomous work vehicle travel system according to claim 3,
wherein multiple work vehicles are deployed in the work site, and the
route element selecting unit selects the next travel route element from the travel route element set on the basis of the vehicle position of each work vehicle and the state information of each work vehicle.

5. The autonomous work vehicle travel system according to any one of
claims 1 to 4,
wherein the travel route element set is a parallel line set constituted by parallel lines that are parallel to each other and divide the area to be worked into rectangular shapes, and movement from one end of one travel route element to one end of another travel route element is executed through U-turn travel by the work vehicle.
6. The autonomous work vehicle travel system according to any one of
claims 1 to 4,
wherein the travel route element set is a mesh line set constituted by mesh lines that divide the area to be worked into a mesh, and a point of intersection between mesh lines serves as a route changeable point where the route of the work vehicle is permitted to be changed.
7. A travel route managing device that manages a travel route of a work
vehicle, the work vehicle including an autonomous travel controlling unit for
traveling autonomously while working in a work site, the device comprising:
an area setting unit that sets an area to be worked in the work site;
a route managing unit that calculates a travel route element set, the travel route element set being an aggregate of multiple travel route elements constituting a travel route covering the area to be worked, and stores the travel route element set so as to be capable of readout; and
a route element selecting unit that selects a next travel route element, which is to be traveled, sequentially from the travel route element set.
8. The travel route managing device according to claim 7,
wherein the area setting unit sets an area on an outer peripheral side of the work site circled by the work vehicle as an outer peripheral area, and sets the inner side of the outer peripheral area as the area to be worked.
9. A travel route generating device that generates a travel route for a
work vehicle that travels while working in a work site, the device comprising:
a route managing unit that calculates a travel route element set, the travel route element set being an aggregate of multiple travel route elements

constituting a travel route covering an area to be worked in the work site, and stores the travel route element set so as to be capable of readout,
wherein the travel route element set is a mesh line set constituted by mesh lines that divide the area to be worked into a mesh, and a point of intersection between mesh lines is set as a route changeable point where the route of the work vehicle is permitted to be changed.
10. The travel route generating device according to claim 9,
wherein both of endpoints of the mesh line are set as route changeable points where the route of the work vehicle is permitted to be changed.
11. The travel route generating device according to claim 9 or 10,
wherein the area to be worked is an N-cornered shape, where N is an
integer of 3 or more;
the travel route element set is constituted by N line sets, from a first line set to an Nth line set; and
each of the line sets includes lines arranged at predetermined intervals, parallel to any one side of the N-cornered shape.
12. The travel route generating device according to claim 11,
wherein the area to be worked is a quadrangle; and
the travel route element set is constituted by a first line set arranged at predetermined intervals and parallel to a first side of the quadrangle, a second line set arranged at predetermined intervals and parallel to a second side of the quadrangle adjacent to the first side, a third line set arranged at predetermined intervals and parallel to a third side of the quadrangle opposite the first side, and a fourth line set arranged at predetermined intervals and parallel to a fourth side of the quadrangle opposite the second side.
13. The travel route generating device according to any one of claims 9 to
12,
wherein the travel route element is defined by positional coordinates of at least two points in the work site, and a route identifier for identifying the travel route element and an attribute value indicating whether the travel route element is untraveled or already traveled are assigned to the travel

route element.
14. A travel route determining device that determines a travel route for a
work vehicle that travels autonomously while working in a work site, the
device comprising:
an area setting unit that sets an area to be worked in the work site;
a route managing unit that calculates a travel route element set, the travel route element set being an aggregate of multiple travel route elements constituting a travel route covering the area to be worked, and stores the travel route element set so as to be capable of readout; and
a route element selecting unit that selects a next travel route element, which is to be traveled next, sequentially from the travel route element set while the work vehicle is traveling within the work site, on the basis of state information, the state information being a result of evaluating a work environment of the work vehicle.
15. The travel route determining device according to claim 14,
wherein the work vehicle is a harvester that harvests a crop while
traveling and stores the crop in a harvested crop tank;
the state information includes an unload request for unloading the harvested crop from the harvested crop tank; and
in response to the unload request, the route element selecting unit selects, from the travel route element set, a travel route element for guiding the work vehicle to a harvested crop unloading parking position.
16. The travel route determining device according to claim 14 or 15,
wherein the state information includes a refueling request to the work
vehicle; and
in response to the refueling request, the route element selecting unit selects, from the travel route element set, a travel route element for guiding the work vehicle to a refueling parking position.
17. The travel route determining device according to any one of claims 14
to 16,
wherein multiple work vehicles are deployed in the work site; and the route element selecting unit selects the next travel route element

from the travel route element set on the basis of the vehicle position of another work vehicle, included in the state information received from the other work vehicle.
18. The travel route determining device according to any one of claims 14
to 17,
wherein the travel route element set is a mesh line set constituted by mesh lines that divide the area to be worked into a mesh, and a point of intersection between mesh lines serves as a route changeable point where the route of the work vehicle is permitted to be changed.
19. The travel route determining device according to any one of claims 14
to 17,
wherein the travel route element set is a parallel line set constituted by parallel lines that are parallel to each other and divide the area to be worked into rectangular shapes, and movement from one end of one travel route element to one end of another travel route element is executed through U-turn travel by the work vehicle.