Movable object including wheel and method of operating the same

1 . A method of operating a movable object that comprises a body part, a plurality of wheels spaced apart from one another in a forward/rearward direction, and a plurality of eccentric drive parts, each eccentric drive part being configured to connect an associated wheel and the body part, wherein each of the eccentric drive parts comprises a connection member having a first side rotatably coupled to the associated wheel and having a second side rotatably coupled to the body part, the method comprising:

controlling the eccentric drive parts to change a relative position between the associated wheel and the body part so that an angle defined between the body part and a ground surface is minimized in a range in which the second side is positioned within a rotatable angle by which the second side is rotatable about the first side, the rotatable angle being restricted within a selected range;

performing a first target setting operation, wherein the first target setting operation comprises setting a target height of the body part with respect to the ground surface and setting a target angle of the body part with respect to the ground surface; and

performing a first determination operation of determining, based on the first target setting operation, whether the second side of the connection member of each of the eccentric drive parts is positioned within the rotatable angle by which the second side is rotatable about the first side.

2 . The method of claim 1 , further comprising setting the rotatable angle by which the second side is rotatable about the first side of the connection member of each of the eccentric drive parts to be smaller than 180 degrees.

3 . The method of claim 1 , further comprising limiting a position of the second side of the connection member of each of the eccentric drive parts to be always positioned outward of the first side based on the forward/rearward direction of the movable object.

4 . The method of claim 1 , wherein the first determination operation comprises determining whether the second side of the connection member of each of the eccentric drive parts is positioned within the rotatable angle by which the second side is rotatable about the first side in a state in which the body part is kept parallel to the ground surface.

5 . A method of operating a movable object that comprises a body part, a plurality of wheels spaced apart from one another in a forward/rearward direction, and a plurality of eccentric drive parts, each eccentric drive part being configured to connect an associated wheel and the body part, wherein each of the eccentric drive parts comprises a connection member having a first side rotatably coupled to the associated wheel and having a second side rotatably coupled to the body part, the method comprising:

controlling the eccentric drive parts to change a relative position between the associated wheel and the body part so that an angle defined between the body part and a ground surface is minimized in a range in which the second side is positioned within a rotatable angle by which the second side is rotatable about the first side, the rotatable angle being restricted within a selected range;

performing a first target setting operation, wherein the first target setting operation comprises setting a target height of the body part with respect to the ground surface and setting a target angle of the body part with respect to the ground surface; and

performing a first determination operation of determining, based on the first target setting operation, whether the second side of the connection member of each of the eccentric drive parts is positioned within the rotatable angle by which the second side is rotatable about the first side; and

performing a body part posture adjustment operation of adjusting a height of the body part in an upward/downward direction based on determining in the first determination operation that the second side of each of at least some of the connection members of the eccentric drive parts deviates from the rotatable angle by which the second side is rotatable about the first side.

6 . The method of claim 5 , wherein the body part posture adjustment operation comprises lowering the body part to decrease the height of the body part in the upward/downward direction in a state in which the body part is parallel to the ground surface and in the state in which the second side of the connection member, which is determined as deviating from an upper boundary, is positioned on the upper boundary of the rotatable angle based on determining in the first determination operation that the connection member, which has the second side determined as deviating from the rotatable angle by which the second side is rotatable about the first side, deviates from the upper boundary of two opposite boundaries in the upward/downward direction of the rotatable angle.

7 . The method of claim 5 , wherein the body part posture adjustment operation comprises raising the body part to increase the height of the body part in the upward/downward direction in a state in which the body part is parallel to the ground surface and in the state in which the second side of the connection member, which is determined as deviating from a lower boundary, is positioned on the lower boundary of the rotatable angle based on determining in the first determination operation that the connection member, which has the second side determined as deviating from the rotatable angle by which the second side is rotatable about the first side, deviates from the lower boundary of two opposite boundaries in the upward/downward direction of the rotatable angle.

8 . The method of claim 5 , wherein the body part posture adjustment operation comprises inclining the body part to adjust the height of the body part while inclining the body part so that the body part has a selected body angle with respect to the ground surface based on determining in the first determination operation that the connection members of a first set of the eccentric drive parts deviate from an upper boundary of two opposite boundaries in the upward/downward direction of the rotatable angle and the connection members of a second set of the eccentric drive parts deviate from a lower boundary of the two opposite boundaries in the upward/downward direction of the rotatable angle.

9 . The method of claim 8 , wherein the inclining of the body part adjusts the height of the body part in a state in which the second side of the connection member, which is determined as deviating from the upper boundary in the first determination operation, is positioned on the upper boundary of the rotatable angle and in the state in which the second side of the connection member, which is determined as deviating from the lower boundary in the first determination operation, is positioned on the lower boundary of the rotatable angle based on determining in the first determination operation that the connection members of a first set of the eccentric drive parts deviate from the upper boundary of the two opposite boundaries in the upward/downward direction of the rotatable angle and the connection members of a second set of the eccentric drive parts deviate from the lower boundary of the two opposite boundaries in the upward/downward direction of the rotatable angle.

10 . The method of claim 9 , wherein the inclining of the body part derives a derived angle defined between the body part and the ground surface from a relationship formula between a first height of the second side of each of the connection members provided in the movable object, a second height of the body part, and the ground angle defined between the body part and the ground surface and inclines the body part while corresponding to the derived angle.

11 . The method of claim 10 , wherein the inclining of the body part derives the derived angle of the body part with respect to the ground surface from the relationship formula by use of a pseudo inverse.

12 . The method of claim 5 , further comprising setting the rotatable angle by which the second side is rotatable about the first side of the connection member of each of the eccentric drive parts to be smaller than 180 degrees.

13 . The method of claim 5 , further comprising limiting a position of the second side of the connection member of each of the eccentric drive parts to be always positioned outward of the first side based on the forward/rearward direction of the movable object.

14 . The method of claim 5 , wherein the first determination operation comprises determining whether the second side of the connection member of each of the eccentric drive parts is positioned within the rotatable angle by which the second side is rotatable about the first side in a state in which the body part is kept parallel to the ground surface.

15 . A method of operating a movable object that comprises a body part, a plurality of wheels spaced apart from one another in a forward/rearward direction, and a plurality of eccentric drive parts, each eccentric drive part being configured to connect an associated wheel and the body part, wherein each of the eccentric drive parts comprises a connection member having a first side rotatably coupled to the associated wheel and having a second side rotatably coupled to the body part, the method comprising:

controlling the eccentric drive parts to change a relative position between the associated wheel and the body part so that an angle defined between the body part and a ground surface is minimized in a range in which the second side is positioned within a rotatable angle by which the second side is rotatable about the first side, the rotatable angle being restricted within a selected range;

performing a first target setting operation, wherein the first target setting operation comprises setting a target height of the body part with respect to the ground surface and setting a target angle of the body part with respect to the ground surface;

performing a first determination operation of determining, based on the first target setting operation, whether the second side of the connection member of each of the eccentric drive parts is positioned within the rotatable angle by which the second side is rotatable about the first side; and

performing a body part posture adjustment operation of adjusting a height of the body part in an upward/downward direction based on determining in the first determination operation that the second side of each of at least some of the connection members of the eccentric drive parts deviates from the rotatable angle by which the second side is rotatable about the first side, wherein the body part posture adjustment operation comprises:

decreasing the height of the body part in the upward/downward direction based on the second side deviating only from an upper boundary,

increasing the height of the body part in the upward/downward direction based on the second side deviating only from a lower boundary, and

inclining the body part to adjust the height of the body part while inclining the body part so that the body part has a selected body angle with respect to the ground surface based on the second side deviating from both the lower boundary and the upper boundary.

16 . The method of claim 15 , wherein the body part posture adjustment operation comprises lowering the body part to decrease the height of the body part in the upward/downward direction in a state in which the body part is parallel to the ground surface and in the state in which the second side of the connection member, which is determined as deviating from the upper boundary, is positioned on the upper boundary of the rotatable angle based on determining in the first determination operation that the connection member, which has the second side determined as deviating from the rotatable angle by which the second side is rotatable about the first side, deviates from the upper boundary of two opposite boundaries in the upward/downward direction of the rotatable angle.

17 . The method of claim 15 , wherein the body part posture adjustment operation comprises raising the body part to increase the height of the body part in the upward/downward direction in a state in which the body part is parallel to the ground surface and in the state in which the second side of the connection member, which is determined as deviating from the lower boundary, is positioned on the lower boundary of the rotatable angle based on determining in the first determination operation that the connection member, which has the second side determined as deviating from the rotatable angle by which the second side is rotatable about the first side, deviates from the lower boundary of two opposite boundaries in the upward/downward direction of the rotatable angle.

18 . The method of claim 15 , wherein the inclining of the body part to adjust the height of the body part while inclining the body part so that the body part has the selected body angle with respect to the ground surface is based on determining in the first determination operation that the connection members of a first set of the eccentric drive parts deviate from the upper boundary of two opposite boundaries in the upward/downward direction of the rotatable angle and the connection members of a second set of the eccentric drive parts deviate from the lower boundary of the two opposite boundaries in the upward/downward direction of the rotatable angle.

19 . The method of claim 18 , wherein the inclining of the body part adjusts the height of the body part in a state in which the second side of the connection member, which is determined as deviating from the upper boundary in the first determination operation, is positioned on the upper boundary of the rotatable angle and in the state in which the second side of the connection member, which is determined as deviating from the lower boundary in the first determination operation, is positioned on the lower boundary of the rotatable angle based on determining in the first determination operation that the connection members of a first set of the eccentric drive parts deviate from the upper boundary of the two opposite boundaries in the upward/downward direction of the rotatable angle and the connection members of a second set of the eccentric drive parts deviate from the lower boundary of the two opposite boundaries in the upward/downward direction of the rotatable angle.

20 . The method of claim 19 , wherein the inclining of the body part derives a derived angle defined between the body part and the ground surface from a relationship formula between a first height of the second side of each of the connection members provided in the movable object, a second height of the body part, and the ground angle defined between the body part and the ground surface and inclines the body part while corresponding to the derived angle.