JP3093580B2 - Drive transmission mechanism for omnidirectional vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive transmission mechanism for an omni-directional vehicle, and more particularly, to a vehicle such as a robot that moves in all directions on a plane, an AGV (automatic guided vehicle), an automobile, and others. The present invention relates to a drive transmission mechanism for an omnidirectional vehicle capable of controlling the traveling of a flat terrain traveling mechanism with high accuracy.

[0002]

2. Description of the Related Art In general, a mobile robot traveling on a flat surface is required to have a stable running. In addition, when a mobile robot behaves in a small environment or works in cooperation with another robot,
It is desirable to be able to freely control the posture and position of the robot in all directions, and many studies have been conducted on robots capable of moving in all directions.

That is, an omnidirectional mobile robot traveling on a plane has a total of three degrees of freedom, two degrees of translation for movement in the X-axis direction and movement in the Y-axis direction, and one degree of freedom for rotation about the Z-axis. Freedom of athletic performance must be possible.

In order to realize the omnidirectional movement of the robot, various improvements have been made to the wheel mechanism. As this kind of moving vehicle, a number of free rollers inclined with respect to the rotation direction of the axle are provided on the outer peripheral portion of the wheel. The drive wheels that are attached to the end of the axle, each of which can be moved in all directions by driving each drive wheel in any direction, the spherical wheel is attached to the end of the axle, Various types have been proposed so far, such as those that can move freely, those that have a free roller attached to a crawler, and those that have a plurality of spherical wheels in contact between two rods in the form of a crawler.

[0005] Among these, a drive wheel having a large number of free rollers on the outer peripheral portion of a wheel is attached to an end of an axle,
As an omnidirectional vehicle that drives each drive wheel in an arbitrary direction, there is, for example, an omnidirectional vehicle disclosed in Japanese Patent Application Laid-Open No. 5-61543.

The omnidirectional vehicle disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 5-61543 has at least four drive wheels having a large number of free rollers on the outer peripheral portion thereof. By controlling the rotation direction and the rotation speed of each drive wheel, the traveling of the omnidirectional vehicle is controlled.

An omnidirectional vehicle using spherical wheels for the wheel mechanism is described in, for example, Shinji Iida, et al., “Omnidirectional Moving Mechanism Using Ball and Its Control” (3rd Robot Symposium, May 1993). On the other hand, as an omnidirectional vehicle using a cylindrical free roller for a wheel mechanism, for example, Shigeo Hirose,
"Development of High Load High Efficiency Omni-directional Vehicle" by others (JSME Robotics and Mechatronics Lecture '93)
Is disclosed.

[0008]

However, in the above-described conventional omnidirectional vehicle, a system in which four wheels are driven by four actuators (motors) using wheels incorporating free rollers is used. A method of driving three wheels by three actuators was common.

In the former case, four actuators must be driven for three degrees of freedom necessary for the movement.
It was pointed out that the mechanism became redundant. That is, there is a problem that one extra actuator is required for three degrees of freedom, the cost is increased, and a control measure cannot be uniquely determined.

In the case of the latter, three wheels are driven by three actuators, so that a redundant mechanism is not provided. However, there are problems such as poor running motion stability and easy fall in the case of transportation. was there.

Further, in both the former case and the latter case, when performing a combined movement of translation and rotation on a plane, there is a problem that it is necessary to convert the movement into the speed of each actuator for controlling each movement. there were.

On the other hand, in the case of using a spherical wheel for the wheel mechanism, since the supporting area of the spherical wheel is small, the load cannot be increased and the floor is easily damaged, and a plurality of spherical wheels are used. In this case, there is no problem in the two-degree-of-freedom translational motion because all the balls perform the same rotational motion. However, in the rotational motion near the turning center, the rotational speed to be generated between the balls greatly fluctuates. There is a problem that slippage occurs between the floor and the floor surface, which lowers the movement efficiency and may damage the floor surface.

The present invention has been made in view of the above-mentioned various problems of the prior art, and an object of the present invention is to provide an omni-directional vehicle that travels by an arbitrary operation signal. Each of the actuators has a mechanism that independently contributes to two translational degrees of freedom and one rotational degree of freedom movement. When performing a combined translational and rotational movement on a plane, each actuator corresponding to each degree of freedom must be It is an object of the present invention to provide a drive transmission mechanism for an omnidirectional vehicle that can control the travel with high accuracy.

[0014]

In order to achieve the above object, the drive transmission mechanism for an omnidirectional vehicle according to the present invention is disposed to face the omnidirectional vehicle so as to translate the omnidirectional vehicle in the coordinate axis X direction. A pair of wheels, a pair of wheels arranged so as to translate the omnidirectional vehicle in the coordinate axis Y direction, and a translation drive of the pair of wheels in the X direction and the Y direction via a differential gear. And an actuator in which the axle of each of the wheels is connected to a drive shaft via a differential gear, and the bevel gear fixed to the end of the drive shaft is arranged to rotate about the Z axis of the coordinate axis. Each of the actuators has two degrees of freedom (translation in the X-axis direction and movement in the Y-axis direction) and one degree of rotation (rotation around the Z-axis) for the omnidirectional vehicle. 3 contributes independently to the degree of freedom, in which to be able to move arbitrarily omnidirectional vehicle in all directions.

[0015]

Based on such a configuration, the omnidirectional vehicle according to the present invention first rotates an actuator that drives the omnidirectional vehicle in the X direction, and the driving force causes the omnidirectional vehicle to move in the X direction. It is transmitted to the differential gear on the side of the wheel to be moved, and the rotation of the wheel enables the omnidirectional vehicle to translate in the X direction. At this time, the opposing wheels on the opposite side are structured so as not to generate resistance to the movement in the X direction due to the action of the free rollers attached to the wheels.

Similarly, when the actuator that drives the omnidirectional vehicle in the Y direction is rotated, the driving force is transmitted to the differential gear on the wheel side that moves the omnidirectional vehicle in the Y direction. It is possible to translate the directional moving vehicle in the Y direction.

Further, when the actuator for rotating the omnidirectional vehicle is rotated, the driving force is transmitted to the differential gear via the bevel gear fixed to the end of the drive shaft, and the driving force is opposite to the rotation direction of the drive shaft. The wheels are driven in the direction. By driving the four wheels in the same rotational direction, it becomes possible to cause the omnidirectional vehicle to rotate around the Z axis.

Therefore, four drive wheels having a large number of free rollers on the outer periphery are provided at the end of the orthogonal axle, and by controlling the rotation direction and the rotation speed of these drive wheels, the front and rear of the moving vehicle can be controlled. , Can move in all directions such as left, right, skew, and spin turn, and can change the position and attitude of a moving vehicle, for example, X of the center of gravity in a rectangular coordinate system.
Three outputs are obtained: the translation speed in the direction and the Y direction, and the turning angular speed of the moving vehicle.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a drive transmission mechanism for an omnidirectional vehicle according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a schematic configuration of a drive transmission mechanism for an omnidirectional vehicle according to the present invention, FIG. 2 is a top view of the omnidirectional vehicle, and FIGS. 3 and 4 are omnidirectional vehicles. 5 is a perspective view showing a differential gear mechanism of the wheel in FIG. 1, and FIG. 6 is a perspective view showing a mounted state of a suspension supporting wheels of an omnidirectional vehicle. It is a front view.

In FIG. 2, the omnidirectional vehicle 1 has wheels 2, 3,... As shown in FIG.
4 and 5 are respectively arranged in four directions. The wheels 2, 3, 4, and 5 are required to have a mechanism for transmitting a driving force in the direction of rotation of the wheels and reducing friction in a direction perpendicular to the plane of rotation. As shown in FIG. 2, each of the wheels 2, 3, 4, and 5 has four barrel-shaped (spindle-shaped) free rollers 6 mounted on its outer periphery.
The arrangement is such that the free rollers 6 are arranged in a double row with a phase shift of 5 degrees, whereby each free roller 6 is arranged such that its ground contact point is equal to the curvature of the wheel, and the wheels 2, 3,.
4, 5 and continuous contact with the floor surface are enabled.

Here, the coordinates of the omnidirectional vehicle 1 are set as shown in FIG. 1, and the coordinate axes are called X, Y and Z. Therefore, when the omnidirectional vehicle 1 translates in the X direction, the wheels 3 and 5 transmit the driving force to the floor, and the wheels 2 and 4 are free in the X direction by the free rollers 6. Similarly, when the omnidirectional vehicle 1 translates in the Y direction, the wheels 2 and 4 transmit a driving force to the floor, and the wheels 3 and 5 are free in the Y direction by the free rollers 6.

Each wheel 2, 3, 4,.
The axle 5 has differential gears 7, 8,
Bevel gears 11a, 12a, 13a, 14a connected to drive shafts 11, 12, 13, 14 via 9, 10 and fixed to the ends of the drive shafts 11, 12, 13, 14, respectively.
Are engaged with the bevel gear 15a of the actuator 15 that rotates the omnidirectional vehicle 1 around the coordinate axis Z.

On the other hand, the drive transmission mechanism of the omnidirectional vehicle 1
An actuator 16 that translates the wheel 3 and the wheel 5 in the coordinate axis X direction, and an actuator 17 that translates the wheel 2 and the wheel 4 in the coordinate axis Y direction are provided. The driving force is transmitted from the worm gears 16a, 17a to the spur gears 20, 21, 22, and 23 fixed to both ends of the rotation transmission shafts 18, 19 via the rotation transmission shafts 18, 19, respectively. .

The spur gears 20 and 21 fixed to both ends of the rotation transmission shaft 18 are engaged with the differential gears 8 and 10 of the wheels 3 and 5 and are fixed to both ends of the rotation transmission shaft 19. Spur gears 22, 23
Are engaged with the differential gears 7 and 9 of the wheels 2 and 4.

The actuators 16, 17
Contributes to the two degrees of freedom of translation of the omnidirectional vehicle 1 (movement in the X-axis direction, movement in the Y-axis direction), and the actuator 15 rotates the omnidirectional vehicle 1 (rotation about the Z-axis).
Each actuator 15, 1
6 and 17 independently contribute to the three degrees of freedom, so that the mobile vehicle can be arbitrarily moved in all directions.

The drive transmission mechanism of the omnidirectional vehicle 1 is provided with differential gears 7, 8, 9, and 10 on the respective wheels 2, 3, 4, and 5, respectively, as shown in FIG. , differential gear is an internal spur gear Z _b, and is capable of generating rotational difference between the side shaft spur gear Z _b by combining bevel gears. Therefore, relation of the differential gear rotation, the omega _a is the rotational speed of the left axis, and a rotational speed of the right axis omega _b, when the rotational speed of the omega _c spur gear Z _b, 2 [omega _c = represented by ω _a + ω _b.

[0028] Thus, the sum of the rotational speeds of the left and right of the axis of the spur gear Z _b, since given by the rotational speed of the spur gears Z _a, so that it can absorb the difference in rotational speeds of the left and right of the axis I have.

Also, as shown in FIG. 6, the omnidirectional vehicle 1 always has four wheels 2, 3,.
A parallel link mechanism 24 is installed so that the floors 4 and 5 are in contact with the floor, and a suspension 25 that can move up and down while keeping the axle horizontal is incorporated.

Further, the drive transmission mechanism of the omnidirectional vehicle 1 according to the present invention may be developed not only to the omnidirectional vehicle but also to a general mechanism that drives independently on a two-dimensional plane in each direction of freedom. it can.

In the above configuration, the four wheels 2, 3,..., So that the driving forces of the three actuators 15, 16, 17 independently contribute to the movement of the omnidirectional vehicle 1 with the respective degrees of freedom of movement.
The operation to be transmitted to 4 and 5 is described.

First, when the actuator 16 is rotated, its driving force is transmitted from the worm gear 16a to the rotation transmitting shaft 1a.
8 and from the spur gears 20 and 21 to the differential gears 8 and 10 to drive the wheels 3 and 5. The rotation of the wheels 3 and 5 enables the omnidirectional vehicle 1 to translate in the X direction (the translation speed in the X direction is the average value of the speeds of the wheels 3 and 5). At this time, the wheel 2 and the wheel 4 are structured so as not to generate a resistance to the movement in the X direction due to the action of the free roller 6 attached to the wheel.
Further, since the driving force is transmitted to the wheels 3 and 5 via the differential gears 8 and 10, when the rotation is performed in addition to the translation, the wheels 3 and 5 are driven by the differential gears 8 and 10. The rotation difference is generated.

Similarly, when the actuator 17 is rotated, the driving force is transmitted from the worm gear 17a to the rotation transmitting shaft 1a.
9 and from the spur gears 22 and 23 to the differential gears 7 and 9 to drive the wheels 2 and 4. The rotation of the wheels 2 and 4 allows the omnidirectional vehicle 1 to translate in the Y direction.

Further, when the actuator 15 is rotated, the driving force is transmitted from the bevel gear 15a to the driving shafts 11, 1 and 1.
Bevel gears 11a, 12 fixed to the ends of 2, 13, 14
a, 13a, 14a through the differential gear 7,
To the drive shafts 11, 12, 13, 1
The wheels 2, 3, 4, 5 are driven in a direction opposite to the rotation direction of the wheel 4. As a result, the omnidirectional vehicle 1 is caused to rotate around the Z axis (the rotation speed around the Z axis is the wheels 2, 3, 4, 5
Average speed).

Next, it is kinematically proved that each of the actuators 16 and 17 independently contributes to a total of three degrees of freedom, that is, two degrees of freedom of translation and one degree of freedom of rotation of the actuator 15.

First, the rotation of the actuator 15 is set to V ₃ , the rotation of the actuator 16 is set to V ₂ , the rotation of the actuator 17 is set to V _1, and the drive shafts 11, 12, 13 corresponding to the wheels 2, 3, 4, 5 are set. , 14 to a ₁ ,
a ₂ , a ₃ , and a ₄ , the rotational speeds on the axle side where the wheels 2, ₃ , _4, and 5 are installed are c ₁ , c ₂ , c ₃ , and c _4, and the rotation transmission shaft 18 having the worm gears 16 a and 17 a , 19 as b ₂ and b ₁ , the following relational expression holds between these speed variables.

A ₁ = a ₂ = a ₃ = a ₄ = k ₃ · V ₃ b ₁ = k ₁ · V ₁ b ₂ = k ₁ · V ₂ , and the equations of the differential gears 7, 8, 9, and 10 are as follows. , the _{-2b 1 · k 2 = a 1} + c 1 2b 1 · k 2 = a 3 + c 3 2b 2 · k 2 = a 2 + c 2 -2b 2 · k 2 = a 4 + c 4.

Where k ₁ is the worm gear 16a, 17
a is the reduction ratio of a, and k ₂ is the differential gears 8 and 10 and the spur gears 22 and 23 that mesh with the spur gears 20 and 21.
, And k ₃ is the reduction ratio of the bevel gears 11a, 12a, 13a, and 14a that mesh with the bevel gear 15a of the actuator 15.

The speeds X '(speed in the X direction), Y' (speed in the Y direction), and Z '(speed in the Z direction) in the respective degrees of freedom.
Are the rotational speeds c ₁ , c ₂ , of the wheels 2, 3, 4, 5 on the axle side,
It is given as follows by c ₃ and c ₄ .

X ′ = １ ／ (c ₂ · r−c ₄ · r) Y ′ = １ ／ (− c ₁ · r + c ₃ · r) Z ′ = − ／ · r / R (c ₁ + C ₂ + c ₃ + c ₄ ) where R is １ ／ of the distance (tread) between the wheels, and r is the diameter of the wheels.

Therefore, when the relational expression of the speed variable is substituted, X ′ = 2k ₁ · k ₂ · r · V ₂ Y ′ = 2k ₁ · k ₂ · r · V ₁ Z ′ = r / R · k ₃ · V _3, and the velocity V _2, V _1, V ₃ of the actuators 15, 16 and 17, the speed X of each degree of freedom ', Y', it can be seen that contributes independently to Z '.

As described above, when the drive transmission mechanism according to the present invention is used, by rotating each of the actuators 15, 16, and 17, the movement of each degree of freedom is generated.
By driving the wheels, the omnidirectional vehicle 1 can be controlled to move in all directions.

From the above results, the omnidirectional vehicle according to the present invention has a mechanism suitable for traveling in a general artificial environment (room, corridor), has excellent traveling stability, and has high kinetic performance. In addition, it is possible to travel along a narrow crank passage or along a rectangular obstacle. Also,
When working with multiple omnidirectional vehicles, flexibly cope with various situations, such as correcting trajectory deviations from disturbances that occur during cooperative actions and evacuating from obstacles caused by other vehicles. Becomes possible. Therefore, there is an advantage that the present invention can be applied to a traveling unit of a moving vehicle that cooperates with a plurality of moving vehicles.

[0044]

Since the present invention is configured as described above, it has the following effects.

At the end of an orthogonal axle grounded to an omnidirectional vehicle, there are provided four drive wheels having a large number of free rollers on the outer periphery, and the rotation direction and the rotation speed of the drive wheels are controlled. Allows the vehicle to move in all directions such as front and rear, left and right, skew, and spin turn, and changes the position and attitude of the vehicle, for example, the translation of the center of gravity in the X and Y directions in a rectangular coordinate system. Three outputs of the speed and the turning angular velocity of the moving vehicle are obtained.

The driving force of the three actuators is 4
It is a mechanism that transmits to the wheel.
No extra actuators are required because the wheels can be driven, and the combined translational and rotational motions of the omni-directional vehicle in the plane are also controlled by controlling each actuator for each degree of freedom. It can be easily realized.

Therefore, according to the present invention, it is possible to obtain a drive transmission mechanism which ensures the running stability of an omnidirectional vehicle, has no redundancy, and can directly control the degree of freedom.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a drive transmission mechanism of an omnidirectional vehicle according to the present invention.

FIG. 2 is a top view of the omnidirectional vehicle.

FIG. 3 is a front view showing wheels of an omnidirectional vehicle.

FIG. 4 is a side view showing wheels of an omnidirectional vehicle.

FIG. 5 is a perspective view showing a differential gear mechanism of the wheel in FIG. 1;

FIG. 6 is a front view showing a mounted state of a suspension supporting wheels of an omnidirectional vehicle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Omnidirectional moving vehicle 2, 3, 4, 5 Wheel 6 Free roller 7, 8, 9, 10 Differential gear 15, 16, 17 Actuator

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihiro Matsumoto 886-1-106 Fujikin, Tsurugashima-shi, Saitama (72) Inventor Isao 2-1 Hirosawa, Wako-shi, Saitama Pref. RIKEN (56) References Special JP-A-63-315377 (JP, A) JP-A-63-149270 (JP, A) JP-A-60-38271 (JP, A) JP-A-5-61543 (JP, A) JP-A-60-1113734 (JP, A) JP, A) JP-A 58-30424 (JP, U) JP-A 40-4803 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B62D 15/00

Claims (3)

(57) [Claims] 1. A pair of wheels arranged so as to translate an omnidirectional vehicle in a coordinate axis X direction, and a pair of wheels opposed to each other so as to translate the omnidirectional vehicle in a coordinate axis Y direction. A pair of wheels, an actuator for translating the pair of wheels in the X direction and the Y direction via a differential gear, and an axle of each wheel connected to a drive shaft via a differential gear. An actuator arranged to rotate a bevel gear fixed to the end of the drive shaft around the Z axis of the coordinate axis, wherein each of the actuators has two degrees of freedom of translation of the omnidirectional vehicle (movement in the X axis direction, Independently contributes to a total of three degrees of freedom, one degree of freedom (movement in the Y axis direction) and rotation (rotation about the Z axis), so that the omnidirectional vehicle can be arbitrarily moved in all directions. A drive transmission mechanism for an omnidirectional vehicle. 2. Each of the wheels of the omnidirectional vehicle has four barrel-shaped free rollers mounted on its outer periphery, and is disposed on the outer periphery of the wheels such that the contact point of the free rollers is equal to the curvature of the wheels. 2. A drive transmission mechanism for an omnidirectional vehicle according to claim 1, wherein said drive transmission mechanism is assembled in a double row with a phase shift of 45 degrees. 3. A moving means for moving up and down while keeping the axle of each wheel horizontal so that each wheel of the omnidirectional vehicle follows irregularities of a moving plane.
Or a drive transmission mechanism for an omnidirectional vehicle according to any one of the above.