OHT vehicle and method of controlling operation of the same

1 . A method of controlling operation of an OHT vehicle, the method comprising:

a steering wheel movement determining step of determining a moving direction of a steering wheel in accordance with a traveling direction of the OHT vehicle in a branching region of a rail;

determining whether the steering wheel is an immovable state;

a dithering motion applying step of applying, in response to the determining that the steering wheel is in the immovable state, a dithering motion to the steering wheel; and

a steering wheel moving step of moving the steering wheel in accordance with the traveling direction of the OHT vehicle.

2 . The method of claim 1 ,

wherein the dithering motion applying step is performed by applying the dithering motion to the steering wheel by sequentially and repeatedly applying a forward torque in the moving direction of the steering wheel and a reverse torque in a direction opposite to the moving direction of the steering wheel.

3 . The method of claim 1 ,

wherein the dithering motion applying step is performed by applying the dithering motion to the steering wheel by sequentially and repeatedly applying a forward dithering current and a reverse dithering current to a steering wheel driving means,

wherein the forward dithering current corresponds to the moving direction of the steering wheel.

4 . The method of claim 3 ,

wherein the dithering motion applying step is performed by applying a dithering current higher by a set range than a moving current applied to the steering wheel driving means to move the steering wheel.

5 . The method of claim 3 ,

wherein the dithering motion applying step is performed by repeatedly performing the applying of the dithering motion to the steering wheel in accordance whether a set dithering condition is satisfied.

6 . The method of claim 1 ,

wherein the steering wheel movement determining step includes:

applying a moving determination current corresponding to the moving direction of the steering wheel to a steering wheel driving means; and

determining a moving state of the steering wheel.

7 . The method of claim 1 ,

wherein the steering wheel movement determining step comprises:

determining the traveling direction of the OHT vehicle in the branching region on the rail; and

determining whether to move the steering wheel in accordance with the traveling direction of the OHT vehicle on the basis of a current position of the steering wheel.

8 . The method of claim 1 ,

wherein the steering wheel moving step comprises:

moving the steering wheel by applying a moving current corresponding to the moving direction of the steering wheel; and

maintaining a position of the steering wheel by applying a holding current.

9 . The method of claim 1 ,

wherein the steering wheel movement determining step or the steering wheel moving step is performed for each of a front end steering wheel and a rear end steering wheel.

10 . An OHT vehicle comprising:

a traveling unit configured to travel along a rail;

a steering unit including a steering wheel and configured to change a traveling direction of the traveling unit; and

a control unit configured to:

determine a moving direction of the steering unit in accordance with the traveling direction of the traveling unit in a branching region on the rail, and

determine whether the steering wheel is an immovable state,

control, in response to determining that the steering wheel is in the immovable state, a dithering motion of the steering unit and movement of the steering unit.

11 . The OHT vehicle of claim 10 ,

wherein the control unit controls a steering wheel driving means of the steering unit by sequentially and repeatedly applying a forward torque in the moving direction of the steering wheel of the steering unit and a reverse torque in a direction opposite to the moving direction.

12 . The OHT vehicle of claim 11 ,

wherein the control unit comprises:

a steering unit controller configured to apply the dithering motion to the steering wheel by sequentially and repeatedly applying a forward dithering current and a reverse dithering current to the steering wheel driving means of the steering wheel, and

wherein the forward dithering current corresponds to the moving direction of the steering wheel.

13 . The OHT vehicle of claim 12 ,

wherein the steering unit controller comprises:

a dithering motion part configured to apply the dithering motion to the steering wheel by sequentially and repeatedly applying the forward dithering current and the reverse dithering current to the steering wheel driving means; and

a steering wheel control part configured to move the steering wheel by applying a moving current to the steering wheel driving means.

14 . The OHT vehicle of claim 13 ,

wherein the steering wheel control part maintains a position of the steering wheel by applying a holding current to the steering wheel driving means after the steering wheel is moved as a result of the application of the moving current.

15 . The OHT vehicle of claim 13 ,

wherein the dithering motion part applies a dithering current higher by a set range than the moving current applied to move the steering wheel.

16 . The OHT vehicle of claim 13 ,

wherein the steering unit controller further comprises a steering movement determining part configured to determine whether to move the steering wheel in accordance with the traveling direction of the OHT vehicle on the basis of a current position of the steering wheel.

17 . The OHT vehicle of claim 16 ,

wherein the steering movement determining part determines a moving state of the steering wheel by applying a moving determination current corresponding to the moving direction of the steering wheel to the steering wheel driving means.

18 . The OHT vehicle of claim 11 ,

wherein the control unit further comprises a traveling unit controller configured to:

determine the traveling direction in the branching region on the rail; and

control a traveling wheel driving means of the traveling unit.

19 . The OHT vehicle of claim 10 ,

wherein the steering unit comprises a front end steering unit and a rear end steering unit, and

wherein the control unit controls the dithering motion and movement of each of the front end steering unit and the rear end steering unit.

20 . A method of controlling operation of an OHT vehicle, the method comprising:

a steering wheel movement determining step of determining a traveling direction of the OHT vehicle in a branching region on a rail and determining whether it is necessary to move a steering wheel in accordance the traveling direction of the OHT vehicle on the basis of a current position of the steering wheel;

determining whether the steering wheel is an immovable state;

a dithering motion applying step of applying, in response to the determining that the steering wheel is in the immovable state, a dithering motion to the steering wheel by sequentially and repeatedly applying to a steering wheel driving means, a forward dithering current corresponding to a moving direction of the steering wheel and a reverse dithering current for a set dithering time; and

a steering wheel moving step of applying to the steering wheel driving means, a moving current corresponding to the moving direction of the steering wheel to cause the steering wheel to be moved, and applying a holding current to cause the steering wheel to maintain its position.