Control system for work vehicle, control method, and work vehicle

1. A control system for a work vehicle including a work implement, the control system comprising:

a controller programmed to

receive actual topography information indicating an actual topography of a work target,

determine a design surface positioned below the actual topography,

generate a command signal to move the work implement along the design surface,

determine if slip of the work vehicle has occurred,

determine whether a blade tip of the work implement is positioned below an initial target surface upon determining slip of the work vehicle has occurred, and

raise the design surface upon determining the blade tip of the work implement when the slip occurred is positioned below the initial target surface, the initial target surface being the design surface before the occurrence of the slip.

2. The control system for a work vehicle according to claim 1 , wherein

the controller is further programmed to raise the design surface at a predetermined speed.

3. The control system for a work vehicle according to claim 1 , wherein

the controller is further programmed to set the design surface to a blade tip position of the work implement at a point in time that the work vehicle emerged from the slip upon determining that the work vehicle has emerged from the slip.

4. The control system for a work vehicle according to claim 3 , wherein

the controller is further programmed set the design surface to not go above the actual topography.

5. The control system for a work vehicle according to claim 3 , wherein

the controller is further programmed to

store as an offset amount ,a difference between

a height of the initial target surface and

a height of the blade tip position of the work implement at the point in time that the work vehicle emerged from the slip, and

set a compensated target surface in which the initial target surface is moved upward by the offset amount, as the design surface after the work vehicle has emerged from the slip.

6. The control system for a work vehicle according to claim 5 , wherein

the controller is further programmed to generate the compensated target surface to not go above the actual topography.

7. The control system for a work vehicle according to claim 1 , wherein

the controller further is programmed to

set the design surface to the blade tip position of the work implement at the point in time that the work vehicle emerged from the slip when the blade tip position of the work implement at the time that the work vehicle emerged from the slip is positioned above the initial target surface, and

set the initial target surface as the design surface after the work vehicle emerged from the slip, when the blade tip position of the work implement at the point in time that the work vehicle emerged from the slip is positioned below the initial target surface.

8. A control method for a work vehicle including a work implement, the method comprising:

receiving actual topography information indicating an actual topography of a work target;

determining a design surface positioned below the actual topography;

generating a command signal to move the work implement along the design surface;

determining if slip of the work vehicle has occurred;

determining whether a blade tip of the work implement is positioned below an initial target surface upon determining slip of the work vehicle has occurred; and

raising the design surface upon determining the blade tip of the work implement when the slip occurred is positioned below the initial target surface, the initial target surface being the design surface before the occurrence of the slip.

9. The control method for a work vehicle according to claim 8 , the method further comprising:

raising the design surface at a predetermined speed.

10. The control method for a work vehicle according to claim 8 , further comprising

setting the design surface to a blade tip position of the work implement at a point in time that the work vehicle emerged from the slip upon determining that the work vehicle has emerged from the slip.

11. The control method for a work vehicle according to claim 10 , further comprising:

setting the design surface not to go above the actual topography when the design surface is set to the blade tip position of the work implement at the point in time that the work vehicle emerged from the slip.

12. The control method for a work vehicle according to claim 10 , further comprising:

storing as an offset amount, a difference between

a height of the initial target surface and

a height of the blade tip position of the work implement at the point in time that the work vehicle emerged from the slip; and

setting a compensated target surface in which the initial target surface is moved upward by the offset amount, as the design surface after the work vehicle has emerged from the slip.

13. The control method for a work vehicle according to claim 12 , wherein

the compensated target surface is generated to not go above the actual topography.

14. The control method for a work vehicle according to claim 8 , wherein

the design surface is set to the blade tip position of the work implement at the point in time that the work vehicle emerged from the slip when the blade tip position of the work implement at the time that the work vehicle emerged from the slip is positioned above the initial target surface, and

the initial target surface is set as the design surface after the work vehicle emerged from the slip, when the blade tip position of the work implement at the point in time that the work vehicle emerged from the slip is positioned below the initial target surface.

15. A work vehicle comprising:

a work implement; and

a controller configured to move the work implement along a design surface positioned below an actual topography of a work target,

upon determining a blade tip of the work implement is positioned below an initial target surface upon determining slip of the work vehicle has occurred, the design surface is raised, the initial target surface being the design surface before the occurrence of the slip.

16. The work vehicle according to claim 15 , wherein

the design surface is raised at a predetermined speed.

17. The work vehicle according to claim 15 , wherein

the design surface is set to a blade tip position of the work implement at a point in time that the work vehicle emerged from the slip upon determining that the work vehicle has emerged from the slip.

18. The work vehicle according to claim 17 , wherein

a difference is stored as an offset amount, the difference being between

a height of the initial target surface and

a height of the blade tip position of the work implement at the point in time that the work vehicle emerged from the slip, and

a compensated target surface in which the initial target surface is moved upward by the offset amount, is set as the design surface after the work vehicle as emerged from the slip.

19. The work vehicle according to claim 18 , wherein

the compensated target surface is generated to not go above the actual topography.

20. The work vehicle according to claim 15 , wherein

the design surface is set to the blade tip position of the work implement at the point in time that the work vehicle emerged from the slip when the blade tip position of the work implement at the time that the work vehicle emerged from the slip is positioned above the initial target surface, and

the initial target surface is set as the design surface after the work vehicle emerged from the slip, when the blade tip position of the work implement at the point in time that the work vehicle emerged from the slip is positioned below the initial target surface.