JP7406209B2 - Omnidirectional moving trolley - Google Patents

Description

The present invention relates to an omnidirectional moving trolley.

Self-propelled trolleys used for inspecting infrastructure structures have limitations such as not being able to make large turns on the spot if the inspection area is a narrow space. Therefore, an omnidirectional mobile cart that can move in any direction has been developed (Non-Patent Document 1).

K. Tadakuma, R. Tadakuma and J. Berengeres, “Development of Holonomic Omnidirectional Vehicle with ”Omini-Ball”: Spherical Wheels, Proceedings of the 2007 IEEE/RSJ International Conference on Intelligent Robots and Systems, San Diego, CA, USA 2007 ).

However, since omnidirectional moving carts are equipped with a plurality of auxiliary wheels on the outer periphery of the main wheels that move in a direction perpendicular to the direction of movement of the main wheels, the joint between the main wheels and the auxiliary wheels is A difference in level occurs. Due to the difference in level, the structure is likely to generate vibrations when the main wheels of the omnidirectional moving cart rotate.

Therefore, even when traveling on a flat road surface, vibrations occur in the wheels of the omnidirectional movable cart, and this vibration is transmitted to the main body of the cart, causing the problem that the main body tends to shake. Furthermore, if the road surface is uneven or uneven, vibrations from the road surface are superimposed on the vibrations described above, causing the main body to vibrate in a more complex manner.

For example, when an omnidirectional mobile trolley is loaded with a mobile measuring device such as an underground radar and is run on a road surface to measure objects such as pipes buried underground, the This causes a problem in that the measuring device vibrates, the distance between the measuring device and the road surface is unstable, and highly accurate measurement data cannot be obtained.

In view of the above circumstances, an object of the present invention is to provide an omnidirectional movable trolley capable of suppressing vibrations during traveling.

An omnidirectional movable trolley according to one aspect of the present invention includes a trolley body, a plurality of omnidirectional movable wheels mounted on the trolley body, and a wheel holding portion that holds an axle of the omnidirectional movable wheels. , at least one of a spring element and a damping element is provided between the wheel holder and the truck body and between the wheel holder and the axle.

According to the present invention, it is possible to suppress vibrations during driving.

FIG. 1 is an external view of an omnidirectional movable trolley according to an embodiment of the present invention. FIG. 2 is a partially exploded perspective view of a coupling mechanism mounted on the omnidirectional movable trolley according to the first embodiment of the present invention. FIG. 3 is an exploded perspective view of a coupling mechanism mounted on the omnidirectional movable trolley according to the first embodiment of the present invention. FIG. 4 is a perspective view showing the detailed configuration of the omniwheel. FIG. 5 is an explanatory diagram showing the operation of an omnidirectional mobile cart equipped with three omni-wheels, (a) when moving forward, (b) when moving forward to the right, and (c) moving towards the right. Indicates when to proceed. FIG. 6A is a graph showing the relationship between the vibration frequency and the acceleration generated in the truck body when the coupling mechanism according to the present embodiment is used. FIG. 6B is a graph showing the relationship between the vibration frequency and the acceleration generated in the truck body when the coupling mechanism according to the present embodiment is not used. FIG. 7 is an explanatory diagram showing a coupling mechanism mounted on an omnidirectional movable cart according to a second embodiment of the present invention, in which (a) is a view seen from the axle direction, and (b) is a view perpendicular to the axle. This is a diagram seen from. FIG. 8 is a graph showing the acceleration response characteristics occurring in the omnidirectional moving trolley, in which (a) shows the change in acceleration when general rubber tires are used, and (b) shows the wheel holder shown in the second embodiment. FIGS. 8(c) and 8(d) show waveforms obtained by frequency analysis of the waveforms shown in FIGS. 8(a) and (b).

[Description of the first embodiment]
DESCRIPTION OF THE PREFERRED EMBODIMENTS An omnidirectional movable trolley according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view schematically showing the configuration of an omnidirectional moving trolley according to this embodiment. As shown in FIG. 1, the omnidirectional moving truck 100 according to the present embodiment includes a truck body 1 and three omniwheels 2a, 2b, and 2c (omnidirectional moving wheels). The truck body 1 has a hexagonal column structure. Below, the three omniwheels 2a, 2b, and 2c may be collectively referred to as "omniwheel 2."

FIG. 2 is a partially exploded perspective view showing the structure of the omni-wheel 2 and the coupling mechanism 3 that connects the omni-wheel 2 to the truck body 1, FIG. 3 is an exploded perspective view, and FIG. 4 shows the detailed structure of the omni-wheel 2. FIG.

As shown in FIGS. 2 to 4, the omniwheel 2 has a disk shape, and an axle 12 is connected to the center. The omniwheel 2 rotates around an axle 12 by a drive mechanism (not shown). Furthermore, a plurality of auxiliary wheels 2A are provided around the omni-wheel 2, as shown in FIG. By rotating the subwheel 2A, it becomes possible to move the omniwheel 2 in the axial direction.

The coupling mechanism 3 includes a fixed member 11, two wheel holders, namely a first wheel holder 16A, a second wheel holder 16B, two coil springs 14 (spring elements), and four elastic polymers. A material 15 (damping element) is provided.

As shown in FIG. 3, the fixing member 11 is made of metal or resin, for example, and has a first longitudinal side surface 11Aa and a second longitudinal side surface 11Ab that are parallel to each other, and a first short side surface that is parallel to each other. It has a hollow quadrangular prism shape consisting of four members: 11Ba and the second short side surface 11Bb.

That is, the first longitudinal side surface 11Aa and the second longitudinal side surface 11Ab are first surfaces perpendicular to the direction of the axle 12 of the omniwheel 2. The first short side surface 11Ba and the second short side surface 11Bb are second surfaces that intersect with the first surface. In this embodiment, the first surface and the second surface are orthogonal.

Furthermore, the two first surfaces sandwich the side surface 1A of the truck body 1 via the elastic polymer material 15 which is a damping element, and the two second surfaces sandwich the side surface 1A via the coil spring 14 which is a spring element. It is sandwiched between the upper end surface 1Aa and the lower end surface 1Ab of the side surface portion 1A.

An opening 111 for inserting the axle 12 is formed in the center of each of the first and second longitudinal sides 11Aa and 11Ab, and screw holes 112a and 112b are formed on both sides of the opening 111, respectively. ing.

The first and second wheel holding parts 16A and 16B have a flat plate shape and are made of metal, for example. A bearing 161 that rotatably supports the axle 12 is provided at the center of each wheel holding portion 16A, 16B. Screw holes 162a and 162b are bored on both sides of the bearing 161, respectively.

The elastic polymer material 15 is made of silicone rubber, for example, and has a rectangular parallelepiped shape. An opening 151 is bored in the center of each elastic polymer material 15 .

In the coupling mechanism 3 according to the present embodiment, a fixing member 11 in the shape of a hollow quadrangular prism is installed so as to surround an axle insertion opening P1 formed in the side surface 1A of the truck body 1. Specifically, the fixing member 11 is arranged so that the centers of the openings 111 formed in the first longitudinal side surface 11Aa and the second longitudinal side surface 11Ab respectively coincide with the center of the opening P1.

Furthermore, the first wheel holding portion 16A is arranged on the outside of the first longitudinal side surface 11Aa (on the opposite side of the side surface portion 1A) so that the centers of the screw holes 112a and 112b and the centers of the screw holes 162a and 162b coincide with each other. bring into contact. A second wheel holding portion 16B is arranged on the outside of the second longitudinal side surface 11Ab (opposite side of the side surface portion 1A) so that the centers of the screw holes 112a and 112b and the centers of the screw holes 162a and 162b coincide with each other, and are in contact with each other. let

Elastic polymer material 15 is arranged at two locations between the inside of the first longitudinal side 11Aa and the side surface 1A, and elastic polymer material 15 is arranged at two locations between the inside of the second longitudinal side 11Ab and the side surface 1A. Place the material 15. Each elastic polymer material 15 is arranged so that the center of the opening 151 coincides with the center of the screw hole 112a or 112b.

A coil spring 14 is disposed between the upper end surface 1Aa of the side surface portion 1A and the first short side surface 11Ba, and a coil spring 14 is similarly arranged between the lower end surface 1Ab of the side surface portion 1A and the second short side surface 11Bb. Place the spring 14.

The axle 12 of the omni-wheel 2 is connected to the bearing 161 of the second wheel holding part 16B, the opening 111 of the second longitudinal side 11Ab, the opening P1 formed in the side surface 1A, and the opening of the first longitudinal side 11Aa. 111, and the bearing 161 of the first wheel holding portion 16A. The axle 12 of the omni-wheel 2 is supported by bearings 161 formed in the first and second wheel holders 16A and 16B.

Two fixing screws 13 are inserted through the first and second wheel holding parts 16A, 16B, the openings 151 of the two elastic polymer materials 15, and the screw holes P2 formed in the side surface 1A. . The two fixing screws 13 are fixed using nuts (not shown) or the like. As a result, the first and second wheel holding portions 16A, 16B, the fixing member 11, and the side surface portion 1A of the truck body 1 can be fixed. In this way, the truck body 1 shown in FIG. 1 and each omniwheel 2a, 2b, 2c are connected using the connection mechanism 3 shown in FIGS. 2 and 3.

At this time, an elastic polymer material 15 (damping element) is installed between the side surface 1A and the first and second longitudinal sides 11Aa and 11Ab, and the upper end surface 1Aa, the lower end surface 1Ab and the first and second Coil springs 14 (spring elements) are installed between the shorter side surfaces 11Ba and 11Bb, respectively. Therefore, even if the omni-wheel 2 runs on a running road surface and vibrations occur, the vibrations generated in the omni-wheel 2 are absorbed by the buffering action of the elastic polymer material 15 and the coil spring, and the vibrations are absorbed. can be suppressed from being transmitted to the truck body 1.

In this embodiment, an elastic polymer material 15, which is an example of a damping element, is installed between the side surface 1A and the first and second longitudinal sides 11Aa, 11Ab, and the upper end surface 1Aa, the lower end surface 1Ab, and the 1. An example is shown in which a coil spring 14, which is an example of a spring element, is installed between the second short side surfaces 11Ba and 11Bb, but when the side surface portion 1A and the first and second long side surfaces 11Aa and 11Ab are At least one of a spring element and a damping element may be installed between the upper end surface 1Aa, the lower end surface 1Ab, and the first and second short side surfaces 11Ba and 11Bb.

For example, a coil spring 14 (spring element) is installed between the side surface 1A and the first and second longitudinal sides 11Aa and 11Ab, and the upper end surface 1Aa, the lower end surface 1Ab and the first and second short side surfaces 11Ba , 11Bb may be provided with an elastic polymer material 15 (damping element). Further, a configuration in which the elastic polymer material 15 or a coil spring 15 is installed only between the side surface 1A and the first and second longitudinal sides 11Aa and 11Ab, and a configuration in which the elastic polymer material 15 or the coil spring 15 is installed between the upper end surface 1Aa, the lower end surface 1Ab and the first and second longitudinal sides 11Aa and 11Ab, It is also possible to adopt a configuration in which the coil spring 15 or the elastic polymer material 15 is installed only between the short side surfaces 11Ba and 11Bb of the two.

[Operation of the first embodiment]
Next, the operation of the omnidirectional mobile cart 100 according to the first embodiment will be described. The omnidirectional moving cart 100 can move in any direction on a two-dimensional plane by controlling the rotation of the three omniwheels 2a, 2b, and 2c. Hereinafter, with reference to FIG. 5, the rotation direction of each omniwheel 2a, 2b, 2c and the movement direction of the omnidirectional movable trolley 100 will be explained. Note that the directions of the up, down, left, and right arrows shown in FIG. 5 are respectively referred to as front, back, left, and right directions.

As shown in FIG. 5(a), by driving the two omni-wheels 2a and 2b in the directions of arrows y1 and y2 with a duty ratio of 100% and stopping the omni-wheel 2c, the omnidirectional mobile cart 100 is moved forward. can be moved to

As shown in FIG. 5(b), the omni-wheel 2a is driven with a duty ratio of 100% in the direction of arrow y1, the omni-wheel 2b is driven with a duty ratio of 26% in the direction of arrow y2, and the omni-wheel 2c is driven with a duty ratio of 26% in the direction of arrow y2. By driving in the direction of y3 with a duty ratio of 73%, the omnidirectional movable cart 100 can be moved to the front right direction.

As shown in FIG. 5(c), the omni-wheel 2a is driven with a duty ratio of 50% in the direction of arrow y1, the omni-wheel 2b is driven with a duty ratio of 50% in the direction of arrow y4, and the omni-wheel 2c is driven with a duty ratio of 50% in the direction of arrow y4. By driving in the direction of y3 at a duty ratio of 100%, the omnidirectional movable cart 100 can be moved to the right.

In this way, by controlling the rotational direction and duty ratio of each of the omni-wheels 2a, 2b, and 2c, the omnidirectional movable cart 100 can be moved in any direction on a two-dimensional plane.

When the omnidirectional movable trolley 100 travels on a running road surface, vibrations occur when the auxiliary wheels 2A (see FIG. 4) provided on the outer periphery of the omni-wheel 2 go over unevenness on the running road surface. Alternatively, even if the road surface is flat, vibrations occur due to unevenness caused by the secondary wheels 2A themselves. These vibrations are transmitted to the first and second wheel holders 16A and 16B via the axle 12, and then to the fixing member 11.

However, a total of four elastic polymer materials 15 are installed between the first and second longitudinal side surfaces 11Aa, 11Ab and the side surface portion 1A. Further, a coil spring 14 is installed between the first short side surface 11Ba and the upper end surface 1Aa and between the second short side surface 11Bb and the lower end surface 1Ab. Therefore, the vibration transmitted to the fixed member 11 is absorbed by the elastic polymer material 15 and the coil spring 14, and can be suppressed from being transmitted to the truck body 1.

Specifically, by installing the elastic polymer material 15, high frequency components of vibration can be attenuated. Further, by installing the coil spring 14, the peak of the amplitude gain with respect to frequency can be shifted. As a result, it is possible to suppress vibrations caused by the rotation of the omni-wheel 2 from being transmitted to the truck body 1.

[Effects of the first embodiment]
As described above, the omnidirectional movable trolley 100 according to the first embodiment includes the trolley body 1, a plurality of omni-wheels 2 (omni-directional movable wheels) mounted on the trolley body 1, and the axle 12 of the omni-wheels 2. It has a wheel holding part 16 for holding, and a coil spring 14 (spring element) and an elastic polymer material 15 (damping element) are provided between the wheel holding part 16 and the truck body 1.

Therefore, it is possible to prevent the vibrations generated in the omni-wheel 2 from being transmitted to the trolley body 1, and it is possible to avoid the problem that the measurement accuracy of the measuring device installed on the mobile trolley 100 is reduced due to vibrations. can.

Further, in the first embodiment, as an example, the elastic polymer material 15 is installed at four locations between the fixing member 11 and the side surface 1A, and immediately above the upper end surface 1Aa of the side surface 1A, and on the lower end surface 1Ab. A coil spring 14 is installed directly below.

By installing the coil spring 14, the peak of the vibration frequency characteristic below 100 [Hz] can be shifted to the lower frequency side. By shifting the peak of the frequency characteristic of vibration to the lower frequency side, it is possible to avoid resonance with the natural vibration of the entire moving trolley 100, and as a result, the vibration occurring in the moving trolley 100 can be reduced.

Furthermore, by providing the elastic polymer material 15, the slope of the damping characteristic in a frequency region higher than the peak of the frequency characteristic of vibration becomes larger. That is, the higher the frequency, the greater the slope at which the vibration amplitude is attenuated. As a result, high frequency vibrations of 100 [Hz] or more can be effectively reduced.

In the coupling mechanism 3 that suppresses such vibrations, experimental results of the acceleration response when vibrations are input to the omniwheel 2 from the floor surface are shown in FIGS. 6A and 6B.

6A and 6B are graphs showing experimental results of acceleration responses to frequency changes when vibrations are input to the omni-wheel 2 from the running road surface while the omni-wheel 2 is running on the running road surface. FIG. 6A shows the results of measuring acceleration responses to frequency changes when the coupling mechanism 3 shown in FIGS. 2 and 3 is mounted, and FIG. 6B shows the results of measuring the acceleration response to frequency changes when the coupling mechanism 3 is not mounted. From the graphs shown in FIGS. 6A and 6B, it is understood that by mounting the coupling mechanism 3 according to the present embodiment, the maximum value of the acceleration response occurring in the moving trolley 100 can be reduced in a wide frequency band.

Therefore, it is possible to suppress the vibrations generated in the omniwheel 2 with a small and simple configuration without using a device having a large damping constant in a low frequency region such as a large oil damper.

Further, the coil spring 14 has a length of several cm, and the elastic polymer material 15 is a small member with a side of about several cm. By using such a small member, the coupling mechanism 3 for suppressing vibration can be mounted on the portion of the omniwheel 2 that holds the axle 12 without increasing the size.

In this way, in the omnidirectional moving trolley 100 according to the first embodiment, the vibrations transmitted to the trolley body 1 can be suppressed, so that measurement accuracy can be improved, for example, when a measuring device is mounted to measure a distance. becomes possible.

In addition, in the first embodiment described above, the elastic polymer material 15 as a damping element is installed between the side surface portion 1A and the first and second wheel holding portions 16A and 16B, and the first and second longitudinal Although the configuration in which the coil spring 14 is installed between the side surfaces 11Aa and 11Ab has been described, the present invention is not limited to this, and the configuration in which the coil spring 14 is installed between the side surface portion 1A and the first and second wheel holding portions 16A and 16B has been described. At least one of a damping element such as an elastic polymer material 15 and a spring element such as a coil spring 14 is provided between the first and second wheel holding parts 16A, 16B and the axle 12. It is good also as a structure provided.

[Description of second embodiment]
Next, a second embodiment of the present invention will be described. FIG. 7 is an explanatory diagram showing the configuration of the wheel holding section 31 mounted on the omnidirectional mobile cart 100 according to the second embodiment, in which (a) is a view seen from the axle direction, and (b) is a view perpendicular to the axle. FIG.

As shown in FIGS. 7(a) and 7(b), a cylindrical elastic polymer material 33 is wound around the axle 12 of the omni-wheel 2. As shown in FIGS. Further, the wheel holder 31 is attached to the truck body 1 (see FIG. 1), and the wheel holder 31 is further provided with a bearing 32. The elastic polymer material 33 is pivotally supported by the bearing 32. That is, the periphery of the cylindrical elastic polymer material 33 is in contact with the inner surface of the bearing 32, and as the omniwheel 2 rotates, the elastic polymer material 33 slides on the inner surface of the bearing 32 and rotates. ing.

With this configuration, high frequency components of vibrations generated in the omni-wheel 2 when the omnidirectional movable trolley 100 is traveling are removed by the elastic polymer material 33 and transmitted to the trolley body 1. As a result, similarly to the first embodiment, it is possible to reduce the acceleration response of vibrations transmitted to the truck body 1 via the wheel holding portions 31, and to suppress vibrations.

Further, since the configuration is extremely simple in that the elastic polymer material 33 is wound around the axle 12, it is possible to further reduce the size and cost.

The vibration suppressing effect of the omnidirectional movable trolley 100 according to the second embodiment will be described below with reference to FIGS. 8(a) to 8(d). FIG. 8(a) shows the change in acceleration when a general rubber tire is used, FIG. 8(b) shows the change in acceleration when the wheel holding part 31 shown in the second embodiment is used, FIG. 8(c), d) shows a waveform obtained by frequency analysis of the waveforms shown in FIGS. 8(a) and 8(b). As can be understood by comparing FIGS. 8(a) and 8(b), by providing the elastic polymer material 33 between the axle 12 and the bearing 32 of the wheel holding part 31, the transmission to the bogie body 1 is It is understood that the vibration caused by this is suppressed. Furthermore, it is understood from FIGS. 8(c) and 8(d) that high frequency components are removed.

In this way, the all-encompassing mobile cart 100 according to the second embodiment holds the cart main body 1, a plurality of omni-wheels 2 (omni-directional moving wheels) mounted on the cart main body 1, and the axle 12 of the omni-wheels 2. The wheel holding part 16 is provided with at least one of a spring element and a damping element between the wheel holding part 16 and the axle 12.

Therefore, as in the first embodiment described above, it is possible to suppress vibrations generated in the omni-wheel 2 from being transmitted to the truck body 1. As a result, when a measuring device is mounted on the trolley body 1 to measure a target object, it is possible to improve measurement accuracy.

In addition, in the embodiment described above, the hexagonal prism-shaped omnidirectional movable trolley 100 provided with three omni wheels 2 was explained as an example, but the present invention allows the trolley to have a shape other than a hexagonal prism. It is. Further, various modifications can be made without departing from the spirit of the present invention, such as increasing the number of omni-wheels to four or more.

1 Bogie body 1A Side part 1Aa Upper end surface 1Ab Lower end surface 2 (2a, 2b, 2c) Omni wheel (omnidirectional moving wheel)
2A Secondary wheel 3 Connection mechanism 11 Fixed member 11Aa First longitudinal side (first surface)
11Ab Second longitudinal side (first side)
11Ba First short side (second side)
11Bb Second short side (second surface)
12 Axle 13 Fixing screw 14 Coil spring (spring element)
15 Elastic polymer material (damping element)
16A First wheel holder 16B Second wheel holder 31 Wheel holder 32 Bearing 33 Elastic polymer material 100 Omnidirectional moving trolley 111 Opening 112a, 112b Screw hole 151 Opening 161 Bearing 162a, 162b Screw hole P1 Opening Part P2 Screw hole

Claims (4)

The trolley body,
a plurality of omnidirectional moving wheels mounted on the truck body;
a wheel holding part that holds an axle of the omnidirectional moving wheel;
a fixing member disposed between the truck main body and the wheel holder,
The fixing member has a first surface perpendicular to the axle direction of the omnidirectional moving wheel and a second surface intersecting the first surface, and is fixed to the truck body,
The wheel holding portion pivotally supports the axle of the omnidirectional moving wheel, and is fixed in contact with the first surface,
At least one of a spring element and a damping element is provided between the first surface and the side surface of the truck body and between the second surface and the upper and lower end surfaces of the side surface.
Omnidirectional moving trolley. The damping element is an elastic polymer material, and the elastic polymer material is disposed between the first surface and the side surface.
The omnidirectional movable trolley according to claim 1. The spring element is a coil spring, and the coil spring is arranged between the second surface and the upper end surface and between the second surface and the lower end surface.
The omnidirectional movable trolley according to claim 1 or 2. The fixing member has a hollow quadrangular prism shape having two first surfaces parallel to each other and two second surfaces parallel to each other,
the two first surfaces sandwiching the side surface through the damping element;
The two second surfaces sandwich the upper end surface and the lower end surface via the spring element.
The omnidirectional movable trolley according to any one of claims 1 to 3.

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