Motion simulator with two degrees of freedom of angular motion

Provided is a motion simulator with two degrees of freedom of angular motion that is capable of performing pitching rotation and yawing rotation. The motion simulator includes: a first rotation body (100) that a user boards; a second rotation body (200) located under the first rotation body (100); a first driving unit (300) for pitching the first rotation body (100); a second driving unit (400) for yawing the first rotation body (100) and the second rotation body (200) as one body; and a controller for controlling rotation of the first driving unit (300) and rotation of the second driving unit (400).

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2015-0167859, filed on Nov. 27, 2015, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

1. Field of the Invention

The present invention relates to a motion simulator with two degrees of freedom of angular motion, and more particularly, to a motion simulator with two degrees of freedom of angular motion that is capable of performing pitching rotation and yawing rotation.

2. Discussion of Related Art

Generally, a motion simulator is a device that allows a user to feel motion of virtual reality like reality by reproducing dynamic changes to be suitable for a virtual environment controlled by a computer. The motion simulator is widely used to realize flying simulation or driving simulation. Additionally, these days, the motion simulator is used as a simulator for a game purpose or a movie theater purpose so that the user can experience three-dimensions (3D).

Korean Patent Laid-open Publication No. 10-2004-0048584 entitled “Motion simulator for virtual reality experience and method of controlling the same” is disclosed as the related art of this motion simulator.

In the motion simulator according to the related art, a first rolling member and a second rolling member can be rotated by 360 degrees in forward, backward, right, and left directions. However, a first driving unit and a second driving unit for rotating the first rolling member and the second rolling member are located at side portions of the first rolling member and the second rolling member such that it is inconvenient for the user to board the motion simulator and a structure for driving the motion simulator is complicated.

SUMMARY OF THE INVENTION

The present invention is directed to a motion simulator that is capable of implementing two degrees of freedom of angular motion of pitching rotation and yawing rotation using a simple structure.

The present invention is also directed to a motion simulator that a user can easily board.

The present invention is also directed to a motion simulator that is capable of rotating a first rotation body using a simple driving method.

The present invention is also directed to a motion simulator in which a first rotation body does not leave a predetermined rotation range.

The present invention is also directed to a motion simulator in which repair of an inside of a control module is easily performed.

The present invention is also directed to a motion simulator in which a power line and a signal line connected from an outside of a device are capable of being connected to a control module without being twisted by using a simple structure.

According to another aspect of the present invention, there is provided a motion simulator with two degrees of freedom of angular motion, including: a first rotation body (100) that a user boards; a second rotation body (200) located under the first rotation body (100); a first driving unit (300) for pitching the first rotation body (100); a second driving unit (400) for yawing the first rotation body (100) and the second rotation body (200) as one body; and a controller for controlling rotation of the first driving unit (300) and rotation of the second driving unit (400).

The first driving unit (300) can be fixed to an upper portion of the second rotation body (200) and supports a lower portion of the first rotation body (100) so that a rotational force is transferred to the first rotation body (100).

The rotational force can be transferred due to a frictional force between the first rotation body (100) and the first driving unit (300).

The first driving unit (300) may comprise: a driving module (310) comprising a first motor (311) for providing a rotational driving force, a pair of driving rollers (314-1and314-2) that rotate by the first motor (311) and rotate the first rotation body (100) due to the frictional force, and a driving shaft (317) that connects the pair of driving rollers (314-1and314-2) and rotates as one body with the pair of driving rollers (314-1and314-2); and a driven module (320) comprising a pair of driven rollers (324-1and324-2) that rotate due to the frictional force and are subordinate to the rotation of the first rotation body (100), and a driven shaft (327) that connects the pair of driven rollers (324-1and324-2) and rotates as one body with the pair of driven rollers (324-1and324-1).

The first rotation body (100) may comprise a first frame (110) and a second frame (120), which are disposed at positions corresponding to the pair of driving rollers (314-1and314-2), and a connection frame (130) that connects between the first frame (110) and the second frame (120), and the first frame (110) and the second frame (120) have curved shapes with uniform curvatures and respectively comprise rotation portions (111and121) that rotate due to a frictional force between surfaces of the driving rollers (314-1and314-2) and the driven rollers (324-1and324-2).

The rotation portions (111and121) may be formed of metal, and portions of the driving rollers (314-1and314-2) that contact the rotation portions (111and121) are formed of urethane.

An encoder (328) for measuring the number of revolutions of the driven roller (324-1) may be provided, and the controller compares a set number of revolutions for rotating the driving roller (314-1) by a set number of revolutions with a measured number of revolutions of the driven roller (324-1) measured by the encoder (328) and increases the number of revolutions of the first motor (311) so as to compensate for a difference between the set number of revolutions and the measured number of revolutions.

The driving module (310) may comprise first bearing housings (313-1and313-2) that are fixed to the upper portion of the second rotation body (200) and support the pair of driving rollers (314-1and314-2) to be rotatable through a medium of a first bearing (318-1), and first roller stoppers (316-1and316-2) that are fixed to upper sides of the first bearing housings (313-1and313-2) and prevent the first rotation body (100) from escaping in an upward direction, and the driven module (320) comprises second bearing housings (323-1and323-1) that are fixed to the upper portion of the second rotation body (200) and support the pair of driven rollers (324-1and324-2) to be rotatable through a medium of a second bearing, and second roller stoppers (326-1and326-2) that are fixed to upper sides of the second bearing housings (324-1and324-2) and prevent the first rotation body (100) from escaping in the upward direction.

The first rotation body (100) may comprise first stoppers (114and124) and second stoppers (115and125) for limiting a range of rotation when pitching rotation of the first rotation body (100) is performed by the first driving unit (300).

The second rotation body (200) may comprise: a second rotation body cover (210) formed to cover the upper portion and side portions of the second rotation body (200); a second rotation body support frame (220) that is provided in the second rotation body cover (210) and supports the second rotation body cover (210); a second rotation body lower frame (230) that supports a lower portion of the second rotation body support frame (220), the second driving unit (400) being mounted on one side of the second rotation body lower frame (230) and a plurality of casters (231) being mounted on a bottom surface of the second rotation body lower frame (230); and a control module (240) in which control components (241) for controlling the first driving unit (300) and the second driving unit (400) are provided, and a fixed frame (500) is provided to support a lower portion of the second rotation body (200) so that the second rotation body (200) is rotatable and has a driven portion engaged with a rotation shaft of the second driving unit (400) and mounted on the fixed frame (500).

A pair of slide rails (225) may be provided on both sides of the second rotation body support frame (220), a pair of rail guides (244) are provided on the control module (240) to be combined with the pair of slide rails (225) to be slidable, and the control module (240) is slidable between an inside and an outside of the second rotation body (200).

First cables (2-1and2-2) and second cables (3-1and3-2) may be provided outside the second rotation body (200) so as to supply power to the control module (240) and to transceive signals, and a first cable carrier (260) is provided so that one end of the first cable carrier (260) is combined with the second rotation body lower frame (220), the other end of the first cable carrier (260) is combined with the control module (240) and the first cables (2-1and2-2) and the second cables (3-1and3-2) pass through an internal space of the first cable carrier (260), and the first cable carrier (260) has a flexible shape to absorb movement displacement of the control module (240) when the control module (240) slides.

A first external cable (2-1) and a second external cable (3-1) may be provided outside the second rotation body (200) and a first internal cable (2-2) and a second internal cable (3-2) are provided in the second rotation body (200) so as to supply power to the control module (240) from an outside of the second rotation body (200) and to transceive signals, and a slip ring (530) is provided to connect the first external cable (2-1) and the first internal cable (2-2) and the second external cable (3-1) and the second internal cable (3-2), respectively, in a state in which the second rotation body (200) rotates.

A slip ring connection member (520) may be provided so that a bottom end of the slip ring connection member (520) is fixed to the fixed frame (500), the slip ring connection member (520) passes through the second rotation body lower frame (220) in a vertical direction, a bearing is interposed between the slip ring connection member (520) and the second rotation body lower frame (220), the slip ring (530) is combined with a top end of the slip ring connection member (520) and a central hole (521) is formed in the slip ring connection member (520) in the vertical direction, and the slip ring (530) may comprise: a first slip ring inner race (531), which surrounds an outside of the slip ring connection member (520), to which the first external cable (2-1) is connected, and which is fixed to the slip ring connection member (520) so that rotation of the first slip ring inner race (531) is prevented; a first slip ring outer race (532), which is provided to surround an outside of the first slip ring inner race (531) through which current flows between sides facing the first slip ring outer race (532) and the first slip ring outer race (532), to which the first inner cable (2-2) is connected, and which is rotated together with the second rotation body (200); a second slip ring outer race (533), which is inserted into a top end of the central hole (521) so that rotation of the second slip ring outer race (533) is prevented, and to which the second external cable (3-1) is connected; and a second slip ring inner race (534), which is inserted into the second slip ring outer race (533) through which current flows between sides facing the second slip ring inner race (534) and the second slip ring inner race (534), and to which the second inner cable (3-2) is connected.

A first hole (522) and a second hole (523) may be formed in the slip ring connection member (522) in a lateral direction so as to communicate with the central hole (521), and after the first external cable (2-1) and the second external cable (3-1) are inserted into the central hole (521) through the first hole (522), the first external cable (2-1) is drawn toward an outside of the slip ring connection member (520) through the second hole (523) and is connected to the first slip ring inner race (531), and the second external cable (3-1) is connected to the second slip ring outer race (533) in the central hole (521).

An angle sensor for measuring a rotation angle is provided on the first rotation body (100), and the controller compares a set rotation angle for rotating the first rotation body (100) to a set rotation angle with a measured rotation angle of the first rotation body (100) measured by the angle sensor and increases the number of revolutions of the first motor (311) so as to compensate for a difference between the set rotation angle and the measured rotation angle.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, a configuration and an operation of exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, when describing movement, a rotation direction, and a degree of freedom with reference toFIG. 1, the movement of an object in a space includes six types of motions, such as a rectilinear motion in forward and backward directions (frontback; Z-axis), a rectilinear motion in a horizontal direction (rightleft; X-axis), a rectilinear motion in a vertical direction (updown; Y-axis), rolling centering on the Z-axis, pitching centering on the X-axis, and yawing centering on the Y-axis, which are referred to as six degrees of freedom.

Hereinafter, an axis that connects the horizontal direction is referred to as the X-axis, an axis that connects the vertical direction is referred to as the Y-axis, and an axis that connects the forward and backward directions is referred to as the Z-axis, as defined inFIG. 1, and when describing a movement and a rotation direction based on these axes, a position in which a monitor102is located on the Z-axis, is referred to as the front, and a position in which a chair101is located on the Z-axis, is referred to as the rear.

Referring toFIGS. 1 and 2, a motion simulator according to the present invention includes a first rotation body100that a user boards, a second rotation body200located under the first rotation body100, a first driving unit300for pitching the first rotation body100, a second driving unit400for yawing the first rotation body100and the second rotation body200as one body, and a controller (not shown) for controlling rotation of the first driving unit300and rotation of the second driving unit400.

The first driving unit300includes a first motor311(FIG. 12), and when the first driving unit300drives the first motor311, the first rotation body100is pitched centering on the X-axis.

The first rotation body100is supported so that a bottom end thereof is rotatable by the first driving unit300. Thus, a rotational force of the first driving unit300is transferred to the first rotation body100. The first driving unit300is fixed to an upper portion of the second rotation body200.

The second driving unit400includes a motor, and when the motor of the second driving unit400is driven, the second rotation body200is yawed centering on the y-axis. In this case, the first driving unit300fixed to the upper portion of the second rotation body200and the first rotation body100supported at an upper portion of the first driving unit300are also yawed as one body together with the second rotation body200.

A fixed frame500and a bottom plate600are provided on a lower portion of the second rotation body200. The fixed frame500supports the lower portion of the second rotation body200so that the second rotation body200is rotatable, and driven portions510and550which are engaged with a rotation shaft of the motor of the second driving unit400are combined with the fixed frame500.

The fixed frame500is fixed to a top surface of the bottom plate600, and a plurality of casters231are provided on the second rotation body200.

The second rotation body200includes a second rotation body cover210, a second rotation body support frame220, a second rotation body lower frame230, a control module240, and a first cable carrier260. The second rotation body cover210is formed to cover the upper portion and side portions of the second rotation body200. The second rotation body support frame220is provided in the second rotation body cover210and supports the second rotation body cover210. The second rotation body lower frame230supports the lower portion of the second rotation body support frame220, and the second driving unit400is mounted on one side of the second rotation body lower frame230, and the plurality of casters231are mounted on a bottom surface of the second rotation body lower frame230. Control components for controlling the first driving unit300and the second driving unit400are provided in the control module240. Both side ends of the first cable carrier260are connected to the second rotation body lower frame230and the control module240, respectively, and cables2-1,2-2,3-1, and3-2(FIG. 16) that will be described below pass through an inside space of the first cable carrier260.

The first rotation body100will be described with reference toFIG. 3.

The first rotation body100includes a chair101on which the user sits, a monitor102that provides a virtual environment formed by a manipulation of the user as an image, a first frame110and a second frame120provided to face each other on right and left sides of the first rotation body100, a plurality of connection frames130that connect the first frame110and the second frame120, a first rotation body upper cover140that covers an upper space between the first frame110and the second frame120, and a first rotation body lower cover150that covers a lower space between the first frame110and the second frame120.

The first frame110and the second frame120include rotation portions111and121that have curved shapes with uniform curvatures and rotate due to the first driving unit300, horizontal connection portions112and122having lengths in the horizontal direction on upper ends of the rotation portions111and121, and vertical connection portions113and123that connect ends of other sides of the horizontal connection portions112and122and ends of lower sides of the rotation portions111and121.

The rotation portions111and121are formed in arc shapes, and first stoppers114and124and second stoppers115and125for limiting the range of rotation when pitching rotation of the first rotation body100is performed by the first driving unit300are provided on both ends of the rotation portions111and121. The first stoppers114and124and the second stoppers115and125protrude from the rotation portions111and121outward in a radial direction so that the first stoppers114and124and the second stoppers115and125catch on driving rollers314-1and314-2(FIG. 12) and driven rollers324-1and324-2(FIG. 12). Since the first stoppers114and124and the second stoppers115and125are provided, the first rotation body100does not leave a predetermined rotation range so that stability is improved.

A plurality of connection frames130may be provided at upper and lower portions of the first rotation body100and in front of and behind the first rotation body100so as to connect the first frame110and the second frame120.

The chair101is provided on the first rotation body lower cover150so that the user boards the motion simulator. The first rotation body lower cover150is provided to cover a space between the first frame110and the second frame120in a predetermined range.

The second rotation body cover210will be described with reference toFIG. 6.

The second rotation body cover210includes an upper cover portion211having a shape of a flat plate to cover the upper portion of the second rotation body200and a side cover portion212that extends from edges of the upper cover portion211to be inclined in a downward direction. A cut opening213is formed in the rear of the side cover portion212so that the control module240is put into or drawn out of the second rotation body200through the opening213. Cut portions214that are cut in rectangular shapes are formed at four edges of the upper cover portion211. First bearing housings313-1and313-2(FIG. 12) and second bearing housings323-1and323-2(FIG. 12) that will be described below pass through the cut portions214.

The second rotation body support frame220will be described with reference toFIG. 7.

The second rotation body support frame220includes a pair of upper frames221aand221bthat have lengths in forward and backward directions and are disposed to be spaced apart from each other in the horizontal direction and to face each other, a plurality of connection frames222that connect the upper frames221aand221b, a plurality of support frames223that support bottom surfaces of the upper frames221aand221band have lengths in the vertical direction, and a pair of lower frames224aand224bthat are combined with bottom ends of the support frames223and disposed on lower portions of the second rotation body support frame220corresponding to the upper frames221aand221b.

The lower frames224aand224bhave L-shaped cross-sections, and slide rails225are combined with inner side surfaces of upright portions of the lower frames224aand224bso that a sliding motion of the control module240may be performed.

The second rotation body lower frame230will be described with reference toFIGS. 8 and 9.

The second rotation body lower frame230is supported to be rotatable by the fixed frame500when the motion simulator operates, and the second rotation body lower frame230supports the entire structure of the motion simulator1when the motion simulator moves. The second rotation body lower frame230includes a first frame232that forms edges of the second rotation body lower frame230and a plurality of second frames233combined with the inner side surface of the first frame232at predetermined angular intervals.

A rotation support portion through hole234through which a rotation support portion (540ofFIG. 16) passes is formed in the center in which the plurality of second frames233meet each other.

The second driving unit400is combined with one side of the second rotation body lower frame230so as to provide a driving force for rotation of the second rotation body lower frame230. The second driving unit400includes a second motor. The second motor is located so that a motor shaft of the second motor is disposed in a downward direction, and a first sprocket410is combined with the motor shaft of the second motor.

A plurality of casters231may be mounted on a bottom surface of the first frame232at predetermined angular intervals, and movement of the motion simulator1may be easily performed so that, when the motion simulator moves, a load of the motion simulator is applied to the casters231.

When the second motor is driven, a rotational force of the second motor is transferred to the driven portions510and550. The driven portions510and550include a plurality of second sprockets510combined with the fixed frame500and a chain550connected to the first sprocket410and the plurality of second sprockets510. The first sprocket410and the second sprockets510are located at the same height. The first sprocket410combined with the shaft of the second motor is located eccentrically outward from a virtual connection line that connects outer circumferential surfaces of the plurality of second sprockets510. Thus, an inner side surface of the chain550is connected to be engaged with an outer side surface of the first sprocket410and outer side surfaces of the plurality of second sprockets510. When the second motor is driven in this connection state, the first sprocket410, the second motor connected to the first sprocket410, the second rotation body200, the first rotation body100, and the first driving unit300are rotated around the rotation support portion540along the inner side surface of the chain550with which the first sprocket410is engaged. The rotation support portion540may include a pair of bearings540aand540b. In this case, the plurality of second sprockets510rotate on their axes. This driving method has been described in Korean Patent Registration No. 10-1250429 and thus, an additional description thereof will be omitted.

The control module240will be described with reference toFIG. 10.

The control module240includes a plurality of control components241for controlling the first driving unit300and the second driving unit400, a cover portion242that covers one side of the control module240, a support plate243having a shape of a flat plate so that lower portions of the control components241are supported, a pair of rail guides244combined with the slide rails255to be slidable, a handle245through which the control module240is easily drawn toward an outside of the second rotation body200, and a cable carrier combination portion246which is formed at an inner end of the support plate243, and with which one end263of the first cable carrier260that will be described later is combined.

As illustrated inFIG. 4, when the control module240is in the second rotation body200, it is very inconvenient to do work for repairing the control components241. Thus, when repair of the control components241is required and the handle245is pulled, the control module240is guided by the slide rails225and is drawn toward the outside of the second rotation body200, like the state illustrated inFIG. 5.

The first cable carrier260will be described with reference toFIG. 11.

The first cable carrier260is configured so that the one end263of the first cable carrier260is combined with the cable carrier combination portion246of the control module240using a fastening member (not shown) and the other end262of the first cable carrier260is combined with the second rotation body support frame220using a fastening member (not shown).

A plurality of carrier pieces261are connected to the first cable carrier260using pins264. Since adjacent carrier pieces261are hinge-coupled to the pins264and have flexible shapes, even though the first cable carrier260is bent, free modification is possible, as illustrated inFIG. 11.

The cables2-1,2-2,3-1, and3-2for supplying power to the control components241of the control module240or transceiving control signals with the control components241of the control module240may include first cables2-1and2-2for supplying power and second cables3-1and3-2for transceiving control signals.

The first cables2-1and2-2and the second cables3-1and3-2pass through inner spaces of the plurality of carrier pieces261via the other end262of the first cable carrier260, are drawn through the one end263of the first cable carrier260and then are connected to the control components241.

Thus, when the control module240is drawn out of the second rotation body200outward in a state in which the other end262of the first cable carrier260is combined with the second rotation body support frame220and a position of the first cable carrier260is fixed, only the one end263of the first cable carrier260is drawn toward the outside of the second rotation body200together with the control module240. In this case, the first cable carrier260may be modified in a flexible shape and thus may absorb a movement displacement of the control module240.

Meanwhile, the second cable carrier270is configured so that one end of the second cable carrier270is combined with an upper portion of the control module240, and the other end of the second cable carrier270is combined with an upper portion of the first rotation body100. A cable (not shown) for supplying power and transceiving control signals is provided to pass through an inner space of the second cable carrier270. One end of the cable is connected to the control components241inside the control module240, and the other end of the cable is connected to the monitor102inside the first rotation body100and components, such as user manipulation tools. Since the second cable carrier270has the same shape as that of the first cable carrier260, the second cable carrier270absorbs displacement when the first rotation body100rotates.

The first driving unit300will be described with reference toFIGS. 12 to 14.

The first driving unit300includes a driving module310that provides a rotational driving force to the first rotation body100and a driven module320that rotates together with the first rotation body100and is subordinate to the rotation of the first rotation body100.

The driving module310includes a first motor311, a decelerator312, a pair of driving rollers314-1and314-2, a driving shaft317, first bearing housings313-1and313-2, and first roller stoppers316-1and316-2.

The first motor311provides a rotational driving force. The decelerator312reduces a rotational force of the first motor311and transfers the reduced rotational force to the driving rollers314-1and314-2. The driving rollers314-1and314-2are rotated by the first motor311and rotate the first rotation body100due to a frictional force. The driving shaft317connects between the pair of driving rollers314-1and314-2and rotates as one body with the driving rollers314-1and314-2. The first bearing housings313-1and313-2are fixed to the upper portion of the second rotation body200and support the driving rollers314-1and314-2to be rotatable through a medium of the first bearing318-1. The first roller stoppers316-1and316-2are fixed to upper sides of the first bearing housings313-1and313-2and prevent the first rotation body100from escaping in an upward direction.

The driving roller314-1provided at one side of the driving shaft317includes a rotation body contact portion314-1ahaving a cylindrical shape, a flange portion314-1bthat protrudes from an outer end of the rotation body contact portion314-1ain a radial direction of the driving shaft317, and a shaft coupling portion314-1cthat protrudes from an outer end of the rotation body contact portion314-1ain a lengthwise direction of the driving shaft317.

The driving shaft317passes centers of the rotation body contact portion314-1a, the flange portion314-1b, and the shaft coupling portion314-1csequentially. The driving shaft317is connected to a shaft312aof the decelerator312in a state in which the driving roller314-1is located between the driving shaft317and the decelerator312. That is, an inner circumferential surface of the rotation body contact portion314-1aof the driving roller314-1is connected to an outer circumferential surface of the driving shaft317using a key so that a rotational force is transferred to the rotation body contact portion314-1a, and an inner circumferential surface of the shaft coupling portion314-1cis connected to an outer circumferential surface of the shaft312aof the decelerator312using the key so that a rotational force is transferred to the shaft coupling portion314-1c.

The first frame110may be formed by forming a metallic pipe, and the rotation body contact portion314-1athat is a portion of the driving roller314-1contacting the rotation portion111may be formed of urethane. Thus, a rotational force is transmitted to the first frame110due to a frictional force between the rotation body contact portion314-1aand the rotation portion111

The first bearing318-1is inserted into the first bearing housing313-1, and the shaft coupling portion314-1cis inserted into the first bearing318-1and thus is smoothly rotated through the medium of the first bearing318-1.

A bottom end of the first bearing housing313-1passes through the cut portions214of the second rotation body cover210and then is combined with the upper frames221aand221bof the second rotation body support frame220using a fastening member (not shown).

A first roller support member315-1is combined with an upper portion of the first bearing housing313-1using a fastening member (not shown). The first roller stopper316-1is combined with the first roller support member315-1. The first roller stopper316-1protrudes from an inner side surface of the first roller support member315-1in the X-axis direction.

The rotation portion111of the first frame110is disposed between the first roller stopper316-1and the rotation body contact portion314-1aof the driving roller314-1. When the driving roller314-1is rotated in a state in which the rotation portion111is in contact with an outer circumferential surface of the rotation body contact portion314-1aand is supported thereon, pitching rotation of the first rotation body100is performed due to a frictional force. In this case, the rotation portion111catches on the first roller stopper316-1and thus is prevented from escaping in an upward direction.

Because the driving roller314-2, the first bearing housing313-2, the first roller support member315-2, the first roller stopper316-2, and a first bearing (not shown), which are disposed on the other side of the driving shaft317have the same configuration as that of the driving roller314-1, the first bearing housing313-1, the first roller support member315-1, the first roller stopper316-1, and the first bearing318-1described above and have a symmetrical structure, a detailed description thereof will be omitted.

Rotation of the first rotation body100is performed in a state in which a rear end of the first rotation body100is supported on the driving module310. On the other hand, no additional driving source is disposed in the driven module320so that the driven rollers324-1and324-2that contact and support the first rotation body100rotate according to the rotation (that is, are subordinate to the rotation) of the first rotation body100due to a frictional force.

The driven module320includes a pair of driven rollers324-1and324-2, a driven shaft327, the second bearing housings323-1and323-2, second roller stoppers326-1and326-2, and second roller support members325-1and325-2.

The driven rollers324-1and324-2rotate due to a frictional force with the rotation portions111and121of the first rotation body100and are subordinate to the rotation of the first rotation body100. The driven shaft327connects between the pair of driven rollers324-1and324-2and rotates as one body with the driven rollers324-1and324-2. The second bearing housings323-1and323-2are fixed to the upper portion of the second rotation body200and support the driven rollers324-1and324-2to be rotatable through a medium of a second bearing. The second roller stoppers326-1and326-2are fixed to upper sides of the second bearing housings323-1and323-2and prevent an upward escape of the first rotation body100. The second roller stoppers325-1and325-2are combined with the second roller support members325-1and325-2.

Because the driven rollers324-1and324-2, the second bearing housings323-1and323-2, the second roller support members325-1and325-2, and the second roller stoppers326-1and326-2have the same configuration as that of the driving rollers314-1and314-2, the first bearing housings313-1and313-2, the first roller support members325-1and325-2, and the first roller stoppers316-1and316-2, which have been described in relation to the driving module310, a detailed description thereof will be omitted.

An encoder328for measuring the number of revolutions of the driven roller324-1is disposed at a side portion of the first bearing housing313-1. A frictional force is generated between the driving roller314-1and the rotation portion111so that rotation of the first rotation body100is performed. When a slip occurs between the rotation body contact portion314-1aof the driving roller314-1and the rotation portion111, the first rotation body100rotates with a smaller number of revolutions than the number of revolutions set by a manipulation of the user.

That is, signals for rotating the driving roller314-1a set number of revolutions (hereinafter, referred to as a ‘set number of revolutions’) are input to the controller using manipulation signals of the user. When the signals are input to the controller, the first motor311is driven by rotation to correspond to the set number of revolutions. For example, even though the first motor311is driven so that the driving roller314-1rotates by the number of revolutions of 1, when a slip occurs, the driving roller314-1rotates only by the number of revolutions of 0.5 that is smaller than 1. Rotation of the driving roller314-1by the number of revolutions of 0.5 means that the rotation portion111that contacts the driving roller314-1rotates by the number of revolutions corresponding to the number of revolutions of 0.5, and the driven roller324-1that contacts the rotation portion111rotates by the number of revolutions of 0.5. Thus, when the encoder328measures the number of revolutions of the driven roller324-1, the controller compares the number of revolutions of the driven roller324-1measured in this way (hereinafter, referred to as a ‘measured number of revolutions’) with the set number of revolutions, and when there is a difference between the set number of revolutions and the measured number of revolutions, the controller controls rotation of the driving roller314-1and rotation of the driven roller324-1to increase the number of revolutions of the first motor311so as to compensate for the difference.

As described above, the number of revolutions of the driven roller324-1is measured using the encoder328so as to compensate for a slip of the driving roller314-1. However, a slip may also be compensated for using an angle sensor (not shown) for measuring a rotation angle of the first rotation body100. That is, the angle sensor is disposed at the first rotation body100and rotates as one body together with the first rotation body100. In this case, the angle sensor can measure an angle at which the first rotation body100is rotated in a direction of gravity (hereinafter, referred to as a ‘measured rotation angle’). When the first motor311is driven so as to rotate the first rotation body100to a desired angle, a rotation angle of the first rotation body100corresponding to the quantity of rotation of the driving roller314-1by rotation of the first motor311(hereinafter, referred to as a ‘set rotation angle’) is defined. When the controller compares the set rotation angle with the measured rotation angle and there is a difference between the set rotation angle and the measured rotation angle, the controller controls rotation of the first rotation body100and rotation of the driving roller314-1to increase the number of revolutions of the first motor311so as to compensate for the difference.

As described above, the first driving unit300is disposed at a lower portion of the first rotation body100, and there is no obstacle in a lateral direction of the first frame110that constitutes the first rotation body100so that boarding of the user can be easily performed. Also, the first driving unit300allows the first rotation body100to be rotated with a frictional force so that a method of driving the first rotation body100can be simplified.

A connection structure of the fixed frame500and a slip ring530will be described with reference toFIGS. 15 and 16.

The first cables2-1and2-2and the second cables3-1and3-2are used to supply power to the control module240and to transceive control signals. The first cables2-1and2-2and the second cables3-1and3-2are classified into a first external cable2-1and a second external cable3-1, which are disposed outside the second rotation body200, and a first internal cable2-2and a second internal cable3-2, which are disposed in the second rotation body200, based on the slip ring530.

Since the second rotation body200having the control module240is yawed, if the first external cable2-1and the second external cable3-1that are drawn outside the second rotation body200extend and are connected to the control module240, twisting of the cables occurs. Thus, the slip ring530is disposed so that the twisting of the cables can be prevented. The slip ring530is combined with a top end of a slip ring connection member520.

The slip ring connection member520has a cylindrical shape with lengths in the vertical direction, and a bottom end of the slip ring connection member520is combined with a fixed frame500band thus is not rotated together with the second rotation body200.

A central hole521is formed in the center of the slip ring connection member520in the vertical direction, and a first hole522and a second hole523are formed in the lateral direction so as to communicate with the central hole521. The second hole523is formed in a higher position than the first hole522.

The slip ring530includes a first slip ring inner race531, a first slip ring outer race532, a second slip ring outer race533, and a second slip ring inner race534.

The first slip ring inner race531having a cylindrical shape surrounds an outside of the slip ring connection member520, is fixed to the slip ring connection member520, and is not rotated and is maintained in a fixed state when the second rotation body200rotates. The first external cable2-1is connected to a bottom end of the first slip ring inner race531.

The first slip ring outer race532having a cylindrical shape is disposed to surround an outside of the first slip ring inner race531and is rotated together when the second rotation body200rotates. The first internal cable2-2is connected to a top end of the first slip ring outer race532.

The first slip ring outer race532and the first slip ring inner race531may be rotated relative to each other in a state in which no current flows between inner side surfaces and outer side surfaces of the first slip ring outer race532and the first slip ring inner race531that face each other.

The first slip ring outer race532may be rotated together with the second rotation body lower frame230by connecting the second rotation body lower frame230and the first slip ring outer race532using a connection member (not shown) so that the first slip ring outer race532is rotated together with the second rotation body200. Alternatively, without using an additional connection member, the first slip ring outer race532may be pulled by the first internal cable2-2connected to the top end of the first slip ring outer race532and may be rotated when the second rotation body200rotates.

The second slip ring outer race533having a cylindrical shape is inserted into a top end of the central hole521, and is not rotated and is maintained in a fixed state when the second rotation body200rotates. The second outer cable3-1is connected to a bottom end of the second slip ring outer race533.

The second slip ring inner race534having a cylindrical shape is inserted into the center of the second slip ring outer race533and is rotated together when the second rotation body200rotates. The second internal cable3-2is connected to a top end of the second slip ring inner race534.

The second slip ring outer race533and the second slip ring inner race534may be rotated relative to each other in a state in which no current flows between inner side surfaces and outer side surfaces of the second slip ring outer race533and the second slip ring inner race534that face each other.

The first external cable2-1and the second external cable3-1are inserted into the central hole521through the first hole522, and are then inserted in the upward direction along the central hole521. The first external cable2-1is drawn from the central hole521toward an outside of the slip ring connection member520through the second hole523, and is then connected to the first slip ring inner race531. The second external cable3-1is connected to the bottom end of the second slip ring outer race533from an inside of the central hole521.

According to this configuration, the first cables2-1and2-2are electrically connected to each other in the order of the first external cable2-1, the first slip ring inner race531, the first slip ring outer race532, and the first internal cable2-2. Also, the second cables3-1and3-2are electrically connected to each other in the order of the second external cable3-1, the second slip ring outer race533, the second slip ring inner race534, and the second internal cable3-2. Thus, rotation of the second rotation body200can be performed in a state in which the first cables2-1and2-2and the second cables3-1and3-2are not twisted between the inside and the outside of the second rotation body200.

Referring toFIG. 17, when the first motor311is driven in a state in which the first rotation body100is supported on upper portions of the driving rollers314-1and314-2, the first rotation body100is pitched due to a frictional force with the driving rollers314-1and314-2. When the first rotation body100is pitched clockwise in a state of a portion indicated by thick solid lines ofFIG. 17, rotation is performed, like in a portion indicated by chain thin double-dashed lines.

As described above, according to the present invention, two degrees of freedom of angular motion of pitching rotation of a first rotation body and yawing rotation of the first rotation body and a second rotation body can be implemented using a simple structure.

In addition, a driving unit for rotating the first rotation body is located on a lower portion of the first rotation body that a user boards, so that boarding of the user is easy.

In addition, the first rotation body is rotated with a frictional force so that a method of driving the first rotation body is simplified.

In addition, stoppers are provided so that the first rotation body does not leave a predetermined rotation range. Thus, stability can be improved.

In addition, a control module makes a sliding motion from the second rotation body so that repair of an inside of the control module can be easily performed.

In addition, a slip ring includes a first slip ring and a second slip ring having a concentric structure so that a power line and a signal line connected from an outside of a device can be connected to the control module without being twisted by using a simple structure.