1. A travel route management system that determines a travel route for a work vehicle that travels autonomously while working in a work site, the 5 system comprising: an area setting unit that sets the work site to an outer peripheral area, and an area to be worked on an inner side of the outer peripheral area; and a route element selecting unit that sequentially selects a next travel route element to be traveled on next, from among multiple mutually-parallel 10 travel route elements, the travel route elements constituting a travel route that covers the area to be worked, wherein the route element selecting unit selects a U-turn travel route for moving from a travel route element serving as a movement origin to a next travel route element serving as a movement destination, the selection being 15 made on the basis of an interval between the movement origin and the movement destination.

2. The travel route management system according to claim 1, wherein the U-turn travel route is a travel route set in the outer 20 peripheral area.

3. The travel route management system according to claim 2, wherein a first U-turn travel route that realizes normal U-turn travel carried out only in a forward direction, and a second U-turn travel route that 25 realizes switchback turn travel carried out in both forward and reverse directions, can be calculated as the U-turn travel route; and the route element selecting unit selects the first U-turn travel route when the interval is large and the second U-turn travel route when the interval is small. 30

4. The travel route management system according to claim 3, wherein the first U-turn travel route includes a rightward U-turn travel route and a leftward U-turn travel route; and the route element selecting unit selects the leftward U-turn travel 35 route preferentially over the rightward U-turn travel route. 79

5. A travel route management system that determines a travel route for a work vehicle that travels autonomously while working in a work site, the system comprising: an area setting unit that sets the work site to an outer peripheral area, 5 and an area to be worked on an inner side of the outer peripheral area; 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 manages the travel route element set so as to be capable of readout, and furthermore 10 manages a plurality of types of directional change routes so as to be capable of readout, the directional change routes being used to move from one of the travel route elements to another travel route element; and a route element selecting unit that, on the basis of a travel pattern set from among a plurality of types of travel patterns defined by combinations of 15 the travel route elements and the directional change routes, selects the next travel route element to be traveled next from the travel route element set in sequence, and selects the directional change travel route for moving to the next travel route element, wherein the setting of the travel pattern is carried out by a human, 20 through a user instruction.

6. The travel route management system according to claim 5, wherein one type of the travel pattern is spiral travel, the spiral travel being spiral work travel from the outside toward the inside of the area to be 25 worked, and another type of the travel pattern is back-and-forth travel in which a U-turn travel route in the outer peripheral area is used as the directional change route for moving from an endpoint of the travel route element to an endpoint of another travel route element. 30 7. The travel route management system according to claim 6, wherein the U-turn travel route includes a first U-turn travel route that realizes normal U-turn travel carried out only in a forward direction and a second U-turn travel route that realizes switchback turn travel carried out in both forward and reverse directions; and 35 the route element selecting unit selects the first U-turn travel route when an interval between a travel route element serving as a movement 80 origin and a travel route element serving as a movement destination, which are to be moved to and which are parallel to each other, is large, and selects the second U-turn travel route when the interval is small. 5 8. The travel route management system according to any one of claims 5 to 7, wherein the travel pattern can be changed partway through the work travel in the area to be worked. 10 9. The travel route management system according to any one of claims 5 to 8, wherein the travel pattern is set by a human, through a user input.

10. A travel route determination device that determines a travel route for 15 a work vehicle that travels while working in a work site, the device comprising: an area setting unit that sets an area to be worked by the work vehicle in the work site; a route managing unit that calculates a travel route element set, the 20 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 first route element selecting unit that calculates a selection order for the travel route elements of an overall travel route on the basis of a basic 25 priority rule, before the work travel by the work vehicle; a second route element selecting unit that, while the work vehicle carries out work travel based on the selection order calculated by the first route element selecting unit, extracts an untraveled travel route element from the travel route element set as a recalculated travel route element, and 30 recalculates a selection order for the recalculated travel route element on the basis of a cost evaluation rule; and a route setting unit that corrects the selection order calculated by the first route element selecting unit with the selection order calculated by the second route element selecting unit. 35

11. The travel route determination device according to claim 10, 81 wherein the second route element selecting unit extracts a predetermined number of travel route elements from the end of the selection order calculated by the first route element selecting unit as the recalculated travel route elements. 5

12. The travel route determination device according to claim 11, wherein the second route element selecting unit repeats the process of extracting the recalculated travel route element and recalculating the selection order while incrementing the predetermined number by additionally 10 extracting a travel route element later in the selection order, and stops the repeating process when the last additionally-extracted travel route element is the travel route element currently being traveled.

13. The travel route determination device according to any one of claims 15 10 to 12, 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 20 U-turn travel by the work vehicle.

14. The travel route determination device according to claim 13, wherein in the basic priority rule, a priority level is set in advance from a travel route element previous in the order to a travel route element 25 next in the order; and the priority level is set so that a properly-distanced travel route element separated by a predetermined distance from a travel route element previous in the order has the highest priority level as the travel route element next in the order, with the priority level decreasing as separation distance 30 from the travel route element previous in the order to the travel route element next in the order increases.

15. The travel route determination device according to claim 13 or 14, wherein a cost evaluated by the cost evaluation rule is a cost arising 35 when the work vehicle travels on the travel route elements according to the selection order calculated by the second route element selecting unit; and 82 a selection order where the cost is the lowest is calculated by the second route element selecting unit.

16. The travel route determination device according to any one of claims 5 13 to 15, wherein the cost depends on a travel distance of the U-turn travel. 83

WE CLAIM:
1. A travel route management system that determines a travel route for
a work vehicle that travels autonomously while working in a work site, the
5 system comprising:
an area setting unit that sets the work site to an outer peripheral area, and an area to be worked on an inner side of the outer peripheral area; and
a route element selecting unit that sequentially selects a next travel route element to be traveled on next, from among multiple mutually-parallel 10 travel route elements, the travel route elements constituting a travel route that covers the area to be worked,
wherein the route element selecting unit selects a U-turn travel route
for moving from a travel route element serving as a movement origin to a next
travel route element serving as a movement destination, the selection being
15 made on the basis of an interval between the movement origin and the
movement destination.
2. The travel route management system according to claim 1,
wherein the U-turn travel route is a travel route set in the outer
20 peripheral area.
3. The travel route management system according to claim 2,
wherein a first U-turn travel route that realizes normal U-turn travel
carried out only in a forward direction, and a second U-turn travel route that 25 realizes switchback turn travel carried out in both forward and reverse
directions, can be calculated as the U-turn travel route; and
the route element selecting unit selects the first U-turn travel route
when the interval is large and the second U-turn travel route when the
interval is small. 30
4. The travel route management system according to claim 3,
wherein the first U-turn travel route includes a rightward U-turn
travel route and a leftward U-turn travel route; and
the route element selecting unit selects the leftward U-turn travel 35 route preferentially over the rightward U-turn travel route.
79

5. A travel route management system that determines a travel route for
a work vehicle that travels autonomously while working in a work site, the
system comprising:
an area setting unit that sets the work site to an outer peripheral area, 5 and an area to be worked on an inner side of the outer peripheral area;
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 manages the travel route element set so as to be capable of readout, and furthermore 10 manages a plurality of types of directional change routes so as to be capable of readout, the directional change routes being used to move from one of the travel route elements to another travel route element; and
a route element selecting unit that, on the basis of a travel pattern set from among a plurality of types of travel patterns defined by combinations of 15 the travel route elements and the directional change routes, selects the next travel route element to be traveled next from the travel route element set in sequence, and selects the directional change travel route for moving to the next travel route element,
wherein the setting of the travel pattern is carried out by a human, 20 through a user instruction.
6. The travel route management system according to claim 5,
wherein one type of the travel pattern is spiral travel, the spiral travel
being spiral work travel from the outside toward the inside of the area to be 25 worked, and another type of the travel pattern is back-and-forth travel in which a U-turn travel route in the outer peripheral area is used as the directional change route for moving from an endpoint of the travel route element to an endpoint of another travel route element.
30 7. The travel route management system according to claim 6,
wherein the U-turn travel route includes a first U-turn travel route
that realizes normal U-turn travel carried out only in a forward direction and
a second U-turn travel route that realizes switchback turn travel carried out
in both forward and reverse directions; and
35 the route element selecting unit selects the first U-turn travel route
when an interval between a travel route element serving as a movement
80

origin and a travel route element serving as a movement destination, which are to be moved to and which are parallel to each other, is large, and selects the second U-turn travel route when the interval is small.
5 8. The travel route management system according to any one of claims 5
to 7,
wherein the travel pattern can be changed partway through the work travel in the area to be worked.
10 9. The travel route management system according to any one of claims 5
to 8,
wherein the travel pattern is set by a human, through a user input.
10. A travel route determination device that determines a travel route for
15 a work vehicle that travels while working in a work site, the device
comprising:
an area setting unit that sets an area to be worked by the work vehicle in the work site;
a route managing unit that calculates a travel route element set, the 20 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 first route element selecting unit that calculates a selection order for the travel route elements of an overall travel route on the basis of a basic 25 priority rule, before the work travel by the work vehicle;
a second route element selecting unit that, while the work vehicle carries out work travel based on the selection order calculated by the first route element selecting unit, extracts an untraveled travel route element from the travel route element set as a recalculated travel route element, and 30 recalculates a selection order for the recalculated travel route element on the basis of a cost evaluation rule; and
a route setting unit that corrects the selection order calculated by the first route element selecting unit with the selection order calculated by the second route element selecting unit. 35
11. The travel route determination device according to claim 10,
81

wherein the second route element selecting unit extracts a predetermined number of travel route elements from the end of the selection order calculated by the first route element selecting unit as the recalculated travel route elements. 5
12. The travel route determination device according to claim 11,
wherein the second route element selecting unit repeats the process of
extracting the recalculated travel route element and recalculating the selection order while incrementing the predetermined number by additionally 10 extracting a travel route element later in the selection order, and stops the repeating process when the last additionally-extracted travel route element is the travel route element currently being traveled.
13. The travel route determination device according to any one of claims
15 10 to 12,
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
20 U-turn travel by the work vehicle.
14. The travel route determination device according to claim 13,
wherein in the basic priority rule, a priority level is set in advance
from a travel route element previous in the order to a travel route element
25 next in the order; and
the priority level is set so that a properly-distanced travel route element separated by a predetermined distance from a travel route element previous in the order has the highest priority level as the travel route element next in the order, with the priority level decreasing as separation distance
30 from the travel route element previous in the order to the travel route element next in the order increases.
15. The travel route determination device according to claim 13 or 14,
wherein a cost evaluated by the cost evaluation rule is a cost arising
35 when the work vehicle travels on the travel route elements according to the selection order calculated by the second route element selecting unit; and
82

a selection order where the cost is the lowest is calculated by the second route element selecting unit.
16. The travel route determination device according to any one of claims 5 13 to 15,
wherein the cost depends on a travel distance of the U-turn travel.
83