JP2001163277A - Rotating drive unit for sphere - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a rotating drive unit capable of simultaneously attaining the free rotating drive of a sphere and the spatial support of the sphere and simplifying the support mechanism of the sphere by using three or more drive rollers for one sphere. SOLUTION: This rotating drive unit for sphere comprises three drive rollers pressed onto the sphere to rotatably support it. The three drive rollers are arranged at equal intervals in the halved height of the sphere and constituted so that the directions of the rotating axes can be freely set within the horizontal plane in the halved height of the sphere, and the three drive rollers are operated so that the rotating speed is conformed to the surface speed of the sphere in the pressure contact point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary driving device for a sphere, which is driven to rotate in all directions by rotating the side surface of the sphere while pressing it with a driving roller or a tire. The present invention relates to a rotary driving device for a new sphere used for driving a joint of a robot arm in addition to being used as a driving device for a transport vehicle or a mobile robot working in a small space.

[0002]

2. Description of the Related Art For example, Patent Application Publication No. 60-1044
In the traveling device disclosed in Japanese Patent Publication No. 75, a sphere is used as a rotating body, and two sets of two driving rollers in contact with one sphere can be rotated in the front-rear, left-right, or oblique directions. You can move and rotate.

In a self-propelled vehicle disclosed in Japanese Patent Application Publication No. 60-38240, three or more spherical wheels are used for a vehicle body, and two rollers circumscribing the wheels are driven and rotated independently of each other. By using the device, the bogie can travel in all directions.

[0004] The ball driving device used in these devices has two driving rollers arranged in a direction perpendicular to each other, and is configured to be able to freely set the rotation axis of the ball by rotating independently of each other. Have something in common.

[0005]

In the above-described prior art, a sphere rotation drive device using two drive rollers for one sphere is provided with a peripheral support mechanism in the rotation direction of the drive roller. Since it is not symmetric, there is a problem that a constant rotational force is not generated in all rotational directions of the sphere. Therefore, when these are used for traveling devices and traveling vehicles,
It becomes difficult to generate a constant thrust in the front-back, left-right, or diagonal directions.

In addition, the fact that the mechanism for supporting the sphere and the mechanism for driving the sphere are complicatedly related to each other has a problem that energy from the driving source cannot be transmitted efficiently. Further, in any case, there is a problem that a complicated and robust support for supporting the sphere is required.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rotary drive device that can simultaneously achieve free rotation of a sphere and spatial support of the sphere by using three or more drive rollers for one sphere. Is what you do.

[0008]

In order to achieve the above object, the present invention comprises three driving rollers for pressing a sphere so as to be rotatable and rotatably supporting the sphere, wherein the three driving rollers are arranged at half the height of the sphere. The rotation axes of the three drive rollers are arranged at equal intervals so that the direction of the rotation axis can be freely set in a horizontal plane at half the height of the sphere, so that the rotation speed of the three drive rollers matches the surface speed of the sphere at the pressure contact. Adopt a spherical rotary drive characterized by driving in

Further, there are provided three or more drive rollers which are in pressure contact with the outer periphery of the sphere and rotatably support the sphere, and each of the three or more drive rollers which are in pressure contact with the outer periphery of the sphere has a peak at each pressure contact point. The three or more driving rollers are arranged so that a square plane passes through the spherical center of the sphere, and the direction of the rotation axis of the sphere can be freely set within the polygonal plane. The present invention employs a rotation driving device for a sphere, which is operated so that the rotation speed of the driving roller matches the surface speed of the sphere at the pressure contact.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

[0011]

FIG. 1 is a perspective view showing a rotary driving device for a spherical body according to a first embodiment of the present invention, wherein a driving motor (1, 2, 3) is shown.
And drive rollers (R1, R2, R
The three driving sources composed of 3) are arranged outside the sphere 7, and are spaced apart from each other by 120 degrees with respect to the sphere center O of the sphere 7, and three driving sources are set at half the height of the sphere 7. The rollers (R1, R2, R3) are pressed at equal intervals. Also,
Each drive source composed of a drive motor and a drive roller is fixed to the fixed base 8 using fixing brackets (4, 5, 6).

The above-mentioned drive motors (1, 2, 3) may be other drive powers that generate rotational force. The driving rollers (R1, R2, R3) for transmitting the driving force to the sphere 7 are made of rubber, but may be made of resin or metal. The sphere 7 receiving the driving force is made of rubber, but may be metal or resin.

The three drive rollers (R1, R2, R3) are pressed against the horizontal outer periphery of the sphere 7, and an equilateral triangle {r1, r2} having the pressure contacts (r1, r2, r3) of each drive roller as vertices. -The plane of r3 passes through the spherical center of the spherical body 7.

FIG. 2 is a front view of the driving device according to the first embodiment, in which an auxiliary caster 9 for supporting the vertical movement of the sphere 7 is mounted at the center of the fixed base 8. In the sphere driving device of the present invention, since the sphere 7 can be rotated while being stopped at one point in space, it is not necessary to constantly support the sphere 7 in the vertical direction. In the first embodiment, the auxiliary caster 9 is provided as an auxiliary support mechanism when an excessively heavy force is applied to the sphere 7 in the vertical direction.

As shown in the first embodiment, when driving sources are arranged at equal intervals around the sphere 7, each driving roller (R1, R2,
R3) and the triangle △ r1, r2, r3 having the pressure contact point (r1, r2, r3) between the sphere 7 as a vertex is an equilateral triangle.
The support force of the driving roller (R1, R2, R3) in the horizontal direction of the sphere 7 becomes uniform. Further, the spherical center O of the sphere 7 coincides with the center of gravity of the triangle, and the equilateral triangle {r1, r2, r
3 inside.

When the sphere 7 is rotated with the structure as in the first embodiment, a rotational force cannot be applied to the sphere 7 independently of the driving rollers (R1, R2, R3). That is, when one of the driving rollers is rotated,
The vertical movement is given to the sphere 7, and the sphere 7
Will be applied to the other two drive rollers via the auxiliary casters 9 that support the vertical direction in the vertical direction, or the sphere 7 will rise. Therefore, the rotational drive of the sphere by three or more drive rollers requires coordinated drive by each drive roller.

First, the basic relationship between the rotating sphere and one drive roller will be described. FIG. 8 is a perspective view of a case where only one roller 10 rotating without resistance is pressed against the already rotating sphere 7, and a sphere having a radius r in which the spherical center O coincides with the coordinate origin in the xyz three-dimensional space is shown. Speed V
, In the direction of θ with respect to the positive direction of the x-axis. At this time, it is assumed that the rotation axis W is on the xy plane.

As shown in FIG. 8, in a sphere 7 already rotating, the speed of a sphere near the rotation axis W is low, and the speed of a sphere away from the rotation axis W is high. Therefore, in the following expressions, the rotational speed V of the sphere 7 uses the speed at the zenith of the sphere 7.

When a driving roller rotating at an arbitrary speed is pressed against an arbitrary place against a sphere rotating at a speed V, an interaction occurs, and friction occurs at a pressing contact. However, in such a case, the interaction can be eliminated by pressing the drive roller against the sphere at a rotational speed that matches the surface speed of the sphere 7.

The surface velocity of the sphere 7 already rotating will now be described. Consider a situation in which the roller 10 that rotates without resistance is pressed at right angles to the outer periphery of the sphere 7 in order to calculate the surface velocity of the sphere 7 that is rotating. That is, in FIG. 8, when the roller 10 that rotates without resistance is pressed against the outer peripheral surface of the sphere 7 at right angles, the roller 10 that rotates without resistance rotates at the surface velocity VR of the sphere 7 at the pressure contact, and the locus LR of the pressure contact is the rotation axis. It becomes circular around W. The speed VR of the roller 10 that rotates without resistance varies depending on the pressure contact location on the outer periphery of the sphere 7, and the locus LR of the pressure contact also varies.

FIG. 9 is a plan view in the xy plane when the roller 10 that rotates without resistance is vertically pressed against the outer periphery of the sphere 7 having a radius r. The sphere 7 is rotating around the rotation axis W. The basic relationship between the rotating sphere 7 and the roller 10 that rotates by pressing without resistance will be described with reference to FIG.

As shown in FIG. 9, when the roller 10 rotating without resistance from the direction of the angle α to the positive x-axis is vertically pressed against the sphere 7 of radius r rotating at the speed V, The trajectory LR is as follows. That is,

[0023]

LR = 2πr · Cos (α−θ)

The circumference L of the sphere 7 of radius r rotating at the speed V is

L = 2πr

When the sphere 7 makes one rotation at the speed V, the locus LR of the pressure contact formed by the roller 10 rotating without resistance also makes one rotation, so that the time required for one rotation is the same in each case. Ie

[0026]

L / V = LR / VR

From this, the rotation speed VR of the roller 10 rotating without resistance matches the surface speed of the sphere 7 at the pressure contact, and can be calculated as follows.

[0028]

## EQU4 ## VR = LR · V / L = 2πr · Cos (α−
θ) · V / 2πr = Cos (α−θ) · V

From the above, when the driving roller is rotated at the above-mentioned speed VR and pressed against the direction of the angle α on the outer periphery of the sphere 7 rotating in the direction of θ at the speed V, the sphere 7 at the pressure contact Since the surface speed of the sphere 7 and the rotation speed of the driving roller are the same, no interaction occurs between the sphere 7 and the sphere driving roller, and the sphere 7 and the sphere driving roller are independent of each other.

Even if a plurality of drive rollers are pressed against the sphere 7 at the same time, the rotational speed VR of each drive roller is adjusted as described above in accordance with the angle α to be pressed, so that the sphere and the plurality of drive rollers can be connected. No interaction occurs between them. At this time, the plurality of drive rollers are mechanically connected via the sphere, but no interaction occurs between the plurality of drive rollers.

FIG. 3 is a plan view of the rotation driving device for a sphere in the first embodiment. Three driving rollers are provided around the sphere 7 at equal intervals of 120 degrees from the center O of the sphere 7 as an origin. Are located. Three drive rollers (R1, R2,
The arrangement angles of R3) are α1 = 0 degrees, α2 = 120 degrees, and α3 = 240 degrees, respectively, based on the driving roller R1. The speed at which the sphere 7 rotates is V, and the rotation direction θ is set at an angle with respect to the driving roller R1.
The case where three drive rollers are arranged at equal intervals at half the height of the sphere 7 will be described below.

Based on the driving roller R1, the arrangement angle α1 = 0 degrees of the three driving rollers (R1, R2, R3),
Three drive rollers (R1, R2, R3) synchronized with the surface velocity of the sphere corresponding to α2 = 120 degrees and α3 = 240 degrees
Can be calculated as follows (VR1, VR2, VR3). That is,

[0033]

V R1 = Cos (θ) · V

[0034]

## EQU00006 ## VR2 = Cos (120-.theta.). V

[0035]

## EQU00007 ## VR3 = Cos (240-.theta.). V

These act on the sphere 7 in the vertical direction. As a result, the sphere 7 rotates about the rotation axis W with the sphere O as the origin.

Further, the rotation speeds (VR1, VR) of the three drive rollers (R1, R2, R3) in the first embodiment.
The algebraic sum of 2, VR3) is as follows. That is,

[0038]

## EQU8 ## VR + VR2 + VR3 = Cos (θ)
・ V + Cos (120-θ) ・ V + Cos (240-
θ) · V = ｛Cos (θ) + Cos (120−θ) + C
os (240−θ)｝ · V = 0

This means that three drive rollers (R1, R
2, R3) rotation speed (VR1, VR2, VR)
By maintaining 3) as in the above equation, the vertical movement acting on the sphere 7 is eliminated, and the sphere O stops at one point in the three-dimensional space and does not move.

FIG. 4 shows the rotation speed (V R) by the three drive rollers (R1, R2, R3) in the first embodiment.
1, VR2, VR3).

In FIG. 4, the driving roller R1 is set at a speed V R
When the ball 1 is pressed against the sphere 7 in the vertical direction, the sphere 7 acts in the vertical direction so as to push the sphere 7 downward. However, as described above, the vertical drive is performed by the coordinated driving by the three drive rollers (R1, R2, R3). Are canceled as a whole, the sphere 7 stops at one point in the space, and the sphere 7 rotates without moving in the vertical direction.

The rotational speed components given from the respective drive rollers to the sphere 7 can represent the rotational speeds (VR1, VR2, VR3) of the three drive rollers as vectors with the zenith of the sphere 7 as a center. The sum of the rotational speeds (VR1, VR2, VR3) of the respective drive rollers gives the actual rotation direction θ and the speed V.

Therefore, the rotation speed (V
The vector sum of R1, VR2, VR3) can be expressed as a vector that gives the rotational speed V and rotational direction θ of the sphere 7 as follows. That is,

[0044]

## EQU9 ## V {θ = ２ (VR1Ｖα1 + VR2 Ｒ)
α2 + VR3∠α3) = 2/3 (VR1∠0 ° + V)
R2∠120 ° + V R3∠240 °)

As shown in the above equation, the sphere 7 rotates in the direction of θ at the velocity V.

From the above, the condition under which the interaction between the sphere 7 and the three driving rollers (R1, R2, R3) in the first embodiment can be completely eliminated is that the sphere 7 has a velocity V and θ
, The three drive rollers (R1, R
2, R3) rotation speed (VR1, VR2, VR3)
Is synchronized with the surface velocity of the sphere at each pressure junction.

That is, the sphere 7 is divided into three drive rollers (R
1, R2, R3) using the rotation speed (V R1, V R
By rotating at R2, VR3), the driving rollers can be rotated in the direction of θ at the speed V while eliminating the interaction between the driving rollers, and a coordinated sphere drive is achieved.

As described above, the three driving rollers (R1, R2, R3) in the first embodiment are rotated (VR1, VR) in synchronization with the surface speed of the sphere 7 at each pressure contact.
2. The sphere 7 is rotated at a speed V by rotating at VR3).
Can rotate in any direction, and can perform cooperative driving without the interaction between the driving rollers.
Up and down movement can be eliminated.

FIG. 5 is a plan view of a second embodiment of the present invention, in which three drive rollers (R
1, R2, R3) are arranged so that a triangular plane having vertices at the pressure contacts (r1, r2, r3) of the sphere 7 passes through the spherical center O of the sphere 7, and the positional relationship between the drive rollers is not particularly limited. This is a typical case. Further, the three drive rollers (R
1, R2, R3), the driving roller R1 and the driving roller R having the spherical center O as the origin so that the spherical center O of the spherical body 7 is located inside the triangle having the vertexes of the pressure contacts (r1, r2, r3).
2 is disposed at an angle of α2 degrees, and the drive roller R1 and the drive roller R3 are disposed at an angle of α3 degrees.

As described above, the three drive rollers (R1, R
2, R3) can be arranged without limiting the positional relationship to each other,
The three drive rollers (R1, R2, R3) are arranged such that the plane of the triangle △ r1, r2, r3 having the vertices at the pressure contacts (r1, r2, r3) of the three drive rollers passes through the spherical center O. The sphere 7 is made up of the three drive rollers (R1, R2,
R3) supports in the horizontal direction.

Further, the rotational speeds of the driving rollers (VR1, VR2) corresponding to the arrangement angle α at which the driving rollers are pressed against each other.
By maintaining R2, VR3), the vertical movement of the sphere 7 is eliminated, and the sphere 7 can be rotated in the direction of θ at the speed V.

Therefore, the pressure contact points (r1, r2) of the three drive rollers (R1, R2, R3) for rotating the sphere 7 are rotated.
In a sphere rotation driving device in which a triangular plane having the vertex of 2, r3) passes through the sphere O of the sphere 7, the velocity V is held while the sphere 7 is stopped in a fixed space and rotatably supported. Can be rotated in the direction of θ.

FIG. 6 is a plan view of a third embodiment of the present invention, showing a case where the number of drive rollers for rotating the spherical body 7 is increased and the number is not limited to n. In this case, the rotation is performed with the dotted line W as the rotation axis in the direction of θ at the speed V. A general case in which the number of rollers for driving the spherical body 7 is not limited will be described with reference to FIG.

When many drive rollers are arranged around the sphere 7 as shown in FIG. 6, the rotation speed VRn of each drive roller can be expressed by the following general formula using the arrangement angle αn. That is,

[0055]

VRn = Cos (αn−θ) · V where n = 1, 2, 3, 4,...

FIG. 7 shows the calculation result of VRn corresponding to the arrangement angle αn of each drive roller based on the above equation.
The rotation speed VR of each drive roller with respect to the arrangement angle α changes in a sinusoidal manner, and when the arrangement angle α rotates 360 degrees, one cycle ends.

According to FIG. 7, the rotational speed VR of the driving roller attached to the periphery of the sphere 7 is symmetrical between positive and negative, and becomes zero in total. This means that when the rotation speed VRn of the drive roller acting on the sphere is positive, the sphere 7 acts in a direction in which the sphere 7 is pressed down, and when the rotation speed VRn is negative, the sphere 7
, The vertical movement of the sphere 7 is in a balanced state, meaning that only the rotational movement is performed while the sphere 7 is kept in a certain space.

Therefore, n driving rollers are arranged along the outer periphery of the sphere 7 and n
The n drive rollers are arranged so that a square plane passes through the spherical center O of the sphere 7, and the rotation speed VRn of each drive roller is determined.
Is maintained at a speed corresponding to the position angle α of the drive roller, the sphere 7 rotates in the direction θ at the speed V while being rotatably supported in a fixed space.

[0059]

According to the sphere rotation driving device of the present invention having the above-described structure, the following effects can be obtained.

That is, since the sphere is arranged so as to surround three or more driving rollers, the sphere is horizontally supported by the driving rollers.

Further, since the vertical movement of the sphere can be eliminated during the rotational driving, the sphere can be rotatably supported in a certain space.

The rotation of the sphere is symmetrical in the front-rear and left-right directions, and can generate a constant rotational force in all directions.

Further, since the drive roller itself also serves as a support, there is no need to provide a robust and complicated sphere support mechanism, and the power of the drive source can be used efficiently by the sphere.

[0064]

[Brief description of the drawings]

FIG. 1 is a perspective view showing a rotation driving device for a sphere according to a first embodiment of the present invention.

FIG. 2 is a front view of the driving device according to the first embodiment.

FIG. 3 is a plan view of a sphere driving device according to the first embodiment.

FIG. 4 shows a vector relationship of rotation speeds (VR1, VR2, VR3) by three drive rollers in the first embodiment.

FIG. 5 is a plan view of a second embodiment of the present invention.

FIG. 6 is a plan view of a third embodiment of the present invention.

FIG. 7 shows a calculation result of VRn corresponding to the arrangement angle αn of each drive roller in the third embodiment of the present invention.

FIG. 8 is a perspective view in xyz space when a roller 10 that rotates without resistance is vertically pressed against the outer periphery of a rotating spherical body 7 having a radius r.

FIG. 9 is a plan view in the xy plane when a roller 10 that rotates without resistance is vertically pressed against the outer periphery of a rotating spherical body 7 having a radius r.

[Explanation of symbols]

 1, 2, 3 Driving power 4, 5, 6 Metal fittings for attaching a driving source to a fixed base 7 Driving sphere 8 Driving source mounting base 9 Auxiliary caster 10 Rollers R1, R2, R3 rotating without resistance Driving roller θ Sphere rotates Angle indicating direction α Arrangement angle of drive roller V Rotation speed of sphere at zenith VR Rotation speed of drive roller

Claims (2)

[Claims] The present invention further comprises three drive rollers for rotatably supporting a sphere by pressing the sphere, wherein the three drive rollers are arranged at equal intervals at half the height of the sphere, and a horizontal plane at half the height of the sphere. Wherein the direction of the rotation axis can be set freely within the sphere, and the rotation of the three drive rollers is operated so as to match the surface speed of the sphere at the pressure contact. 2. A multi-stage apparatus comprising three or more drive rollers which are in pressure contact with the outer periphery of a sphere and rotatably support the sphere, and each pressure contact of the three or more drive rollers in pressure contact with the outer periphery of the sphere is an apex. The three or more drive rollers are arranged so that a rectangular plane passes through the spherical center of the sphere, and the direction of the rotation axis of the sphere can be freely set within the polygonal plane.
A rotation driving device for a sphere, wherein the driving is performed so that the rotation speeds of the one or more driving rollers match the surface speed of the sphere at the pressure contact.