AUTONOMOUS MOBILE DEVICE AND OPERATING METHOD FOR THE SAME

• US 20140121876A1
• Filed: 07/18/2013
• Published: 05/01/2014
• Est. Priority Date: 10/30/2012
• Status: Active Grant

• Current Assignee: ASUSTek Computer, Inc.
• Original Assignee: Agait Technology Corporation
• Inventors: CHEN, Tien-Chen, LEE, Kai-Sheng
• Granted Patent: US 8,918,241 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: G05D 1/0219 ensuring the processing of the whole working surface
• CPC Class Codes: G05D 1/0225 involving docking at a fixed facility, e.g. base station or loading bay parking aids B62D15/027
• 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
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30
• CPC Class Codes: Y10S 901/16 Cartesian, three degrees of freedom

Abstract

An autonomous mobile device is configured to move on a surface provided with a base station thereon, and is operated in one of a work state and return state. In the work state, the autonomous mobile device is operable to plot a movement route along which the autonomous mobile device moves, and is operable to adjust the movement route upon presence of an obstacle. In the return state, the autonomous mobile device is operable to plot a returning route on the surface from the current position to the base station, and to move along the returning route to the base station.

Claims

1. An autonomous mobile device configured to move on a surface provided with a base station thereon, said autonomous mobile device comprising:

a housing;

a motion control module disposed at said housing for controlling movement of said autonomous mobile device;

a detecting module disposed at said housing for detecting presence of an obstacle near said housing; and

a processor coupled to said motion control module and said detecting module, and configured to operate said autonomous mobile device in one of a work state and return state;

wherein, in the work state, said processor is operable to plot a movement route on the surface and to control said motion control module to move said autonomous mobile device along the movement route on the surface, and is operable to adjust the movement route upon presence of an obstacle detected by said detecting module;

wherein, in the return state, said processor is operable to

partition a portion of the surface, over which said autonomous mobile device moves in the work state, into a plurality of virtual blocks,

determine a starting one of the virtual blocks where said autonomous mobile device currently locates, a destination one of the virtual blocks where the base station locates, and an exclusion one of the virtual blocks where the obstacle locates,

using the virtual blocks except the exclusion one, plot a returning route on the surface from the starting one to the destination one of the virtual blocks, and

control said motion control module to move said autonomous mobile device along the returning route to the base station.

2. The autonomous mobile device of claim 1, wherein:

said detecting module includes a front collision sensor disposed at a front position on said housing where said front collision sensor always faces forward when said autonomous mobile device moves straight;

when said autonomous mobile device moves straight and said front collision sensor first detects a surrounding wall, which surrounds the surface, at an initial position, said processor operates said autonomous mobile device in the work state with a contouring mode, in which said processor controls said movement control module to move said autonomous mobile device around the surrounding wall until said autonomous mobile device is returned to the initial position; and

after said autonomous mobile device returns to the initial position in the contouring mode, said processor is operable to switch from the contouring mode to a ransacking mode, in which said processor controls said movement control module to move said autonomous mobile device in a forward direction, to rotate said autonomous mobile device to face a transverse direction, to move said autonomous mobile device in the transverse direction by a transverse distance, to rotate said autonomous mobile device to face an inverse direction opposite to the forward direction, and to move said autonomous mobile device in the inverse direction.

3. The autonomous mobile device of claim 2, wherein:

said detecting module is further for continuously detecting a current position of said autonomous mobile device on the surface, for detecting an angle, at which said autonomous mobile device rotates when said autonomous mobile device rotates, and for outputting to said processor the current position and the angle thus detected; and

in the contouring mode, said processor is operable to

record, respectively as a rotating position and a rotation angle, the current position and the angle received from said detecting module whenever said autonomous mobile device rotates by an angle greater than a predetermined value,

record, as an interval position, the current position of said autonomous mobile device received from said detecting module every time after said autonomous mobile device moves a predetermined distance, and

derive a fitting equation expressing the interval positions between successive two of the rotating positions based on said interval positions.

4. The autonomous mobile device of claim 3, wherein, in the ransacking mode, said processor is operable to:

when said detecting module detects an obstacle, determine whether a present position of said autonomous mobile device can be expressed by the fitting equation;

when it is determined that the present position can be expressed by the fitting equation, control said movement control module to rotate said autonomous mobile device to face the transverse direction, to move said autonomous mobile device in the transverse direction by the transverse distance, to rotate said autonomous mobile device to face the inverse direction, and to move said autonomous mobile device in the inverse direction.

5. The autonomous mobile device of claim 4, wherein, when it is determined that the present position cannot be expressed by the fitting equation, said processor operates said autonomous mobile device in the contouring mode and controls said movement control module to move said autonomous mobile device around the obstacle until said autonomous mobile device returns to the present position.

6. The autonomous mobile device of claim 1, wherein said processor operates said autonomous mobile device in the return state when said autonomous mobile device has travelled thoroughly over the surface, when said processor detects that an amount of electrical power stored in said power storage unit is less than a threshold, or when said autonomous mobile device receives an external return signal.

7. The autonomous mobile device of claim 1, wherein:

said processor is operable to assign a number to each of the virtual blocks of the surface; and

a value of the number assigned to one of the virtual blocks is monotonically related to a block distance between said one of the virtual blocks and the destination one of the virtual blocks.

8. The autonomous mobile device of claim 7, wherein the values of the numbers assigned to the virtual blocks are gradually increased as the block distances increase,

wherein, in the return state, said processor is operable to

plot the returning route by identifying all possible ways to move said autonomous mobile device across successive two of the virtual blocks, calculating, for each of the possible ways, a sum of the values of the numbers that are assigned to the successive two of the virtual blocks, and selecting one of the possible ways that has a smallest sum as a part of the returning route, and

control said movement control module to move said autonomous mobile device, along the selected one of the possible ways, to a first one of the successive two of the virtual blocks.

9. The autonomous mobile device of claim 8, wherein said processor is operable to partition the portion of the surface into the virtual blocks with reference to a first axis and a second axis perpendicular to the first axis,

wherein, when more than one of the possible ways have the smallest sum, said processor is operable to select one of the possible ways that has the smallest sum and that is along one of the first and second axes toward the base station as the part of the returning route.

10. The autonomous mobile device of claim 1, wherein said detecting module includes a front collision detector, an altitude detector, and an accelerometer,

wherein said processor is operable to control said autonomous mobile device to move backward by a safety distance and to rotate at a safety angle before moving said autonomous mobile device again when said front collision detector detects a nearby obstacle, when said altitude detector detects a vertical distance between a bottom side of said housing and the surface greater than a predetermined safe height, or when said accelerometer detects an inclination steeper than a predetermined safe inclination.

11. An operating method of an autonomous mobile device configured to move on a surface provided with a base station thereon, the autonomous mobile device including

a motion control module for controlling movement of the autonomous mobile device, a detecting module for detecting presence of an obstacle, and a processor coupled to the motion control module and the detecting module, said operating method comprising the following steps of:

(a) operating, by the processor, the autonomous mobile device in a work state with the following sub-steps of

plotting a movement route on the surface,

controlling the motion control module to move the autonomous mobile device along the movement route on the surface, and

adjusting the movement route upon presence of an obstacle detected by the detecting module; and

(b) operating, by the processor, the autonomous mobile device in a return state with the following sub-steps of

partitioning a portion of the surface, over which the autonomous mobile device moves in the work state, into a plurality of virtual blocks,

determining a starting one of the virtual blocks where the autonomous mobile device currently locates, a destination one of the virtual blocks where the base station locates, and an exclusion one of the virtual blocks where the obstacle locates,

using the virtual blocks except the exclusion one to plot a returning route on the surface from the starting one to the destination one of the virtual blocks, and

controlling the motion control module to move the autonomous mobile device along the returning route to the base station.

12. The operating method of claim 11, the detecting module including a front collision sensor disposed at a front position on the housing, the front collision sensor always facing forward when the autonomous mobile device moves straight, wherein in step (a):

when the autonomous mobile device moves and the front collision sensor first detects a surrounding wall that surrounds the surface, at an initial position, the processor operates the autonomous mobile device in the work state with a contouring mode, in which the processor control the movement control module to move the autonomous mobile device around the surrounding wall until the autonomous mobile device is returned to the initial position; and

after the autonomous mobile device returns to the initial position in the contouring mode, the processor switches from the contouring mode to a ransacking mode, in which the processor controls the movement control module to

move the autonomous mobile device in a forward direction,

rotate the autonomous mobile device to face a transverse direction,

move the autonomous mobile device in the transverse direction by a transverse distance,

rotate the autonomous mobile device to face an inverse direction opposite to the forward direction, and

move autonomous mobile device in the inverse direction.

13. The operating method of claim 12, wherein the detecting module of the autonomous mobile device continuously detects a current position of the autonomous mobile device on the surface, and detects an angle, at which the autonomous mobile device rotates when the autonomous mobile device rotates, and in step (a), when in the contouring mode, the processor executes the following operations:

recording, respectively as a rotating position and a rotation angle, the current position and the angle received from the detecting module whenever the autonomous mobile device rotates by an angle greater than a predetermined value,

recording, as an interval position, the current position of the autonomous mobile device received from the detecting module every time after the autonomous mobile device moves a predetermined distance, and

deriving a fitting equation expressing the interval positions between successive two of the rotating positions based on the interval positions.

14. The operating method of claim 12, wherein in step (a), when in the ransacking mode, the processor executes the following operations:

upon detection of an obstacle, determining whether a present position of the autonomous mobile device can be expressed by the fitting equation; and

when it is determined that the present position can be expressed by the fitting equation, controlling the movement control module to

rotate the autonomous mobile device to face the transverse direction, moving the autonomous mobile device in the transverse direction by the transverse distance, rotating the autonomous mobile device to face the inverse direction, and moving the autonomous mobile device in the inverse direction.

15. The operating method of claim 14, wherein when it is determined that the present position cannot be expressed by the fitting equation, the processor operates the autonomous mobile device in the contouring mode and controls the movement control module to move the autonomous mobile device around the obstacle until the autonomous mobile device returns to the present position.

16. The operating method of claim 11, the autonomous mobile further including a power storage unit that is coupled to the processor, wherein, the processor operates the autonomous mobile device in the return state when one of the following occurs:

the autonomous mobile device has travelled thoroughly over the surface;

detection, by the processor, that an amount of electrical power stored in the power storage unit is less than a threshold; and

receipt of an external return signal.

17. The operating method of claim 11, further comprising assigning, by the processor, a number to each of the virtual blocks of the surface;

and

a value of the number assigned to one of the virtual blocks is monotonically related to a block distance between the one of the virtual blocks and the destination one of the virtual blocks.

18. The operating method of claim 17, wherein the values of the numbers assigned to the virtual blocks are gradually increased as the block distances increase,

wherein, in step (b), the processor executes the following operations:

plotting the returning route by identifying all possible ways to move the autonomous mobile device across successive two of the virtual blocks, calculating, for each of the possible ways, a sum of the values of the numbers that are assigned to the successive two of the virtual blocks, and selecting one of the possible ways that has a smallest sum as a part of the returning route, and

controlling the movement control module to move the autonomous mobile device, along the selected one of the possible ways, to a first one of the successive two of the virtual blocks.

19. The operating method of claim 18, wherein the processor partitions the portion of the surface into the virtual blocks with reference to a first axis and a second axis perpendicular to the first axis,

wherein, when more than one of the possible ways have the smallest sum, the processor selects one of the possible ways that has the smallest sum and that is along one of the first and second axes toward the base station as the part of the returning route.

20. The operating method of claim 11, the detecting module of the autonomous mobile device including a front collision detector, an altitude detector, and an accelerometer, wherein said operation method further comprising controlling, by the processor, the autonomous mobile device to move backward by a safety distance and to rotate at a safety angle before moving the autonomous mobile device again when the front collision detector detects a nearby obstacle, when the altitude detector detects a vertical distance between a bottom side of said housing and the surface greater than a predetermined safe height, or when the accelerometer detects an inclination steeper than a predetermined safe inclination.