JP7643197B2 - Automated guided vehicles - Google Patents

Description

The present invention relates to an automated guided vehicle.

Automation of tasks is progressing in manufacturing and logistics.
For example, automated guided vehicles are used to transport workpieces in factories, warehouses, and the like.
In recent years, a magnetic guidance system, a laser radar guidance system, or a simultaneous localization and mapping (SLAM) guidance system has been used to guide an automatic guided vehicle.
Patent Document 1, an example of prior art, discloses a laser radar guidance system in which reflectors are installed in advance on the travel path, and the automated guided vehicle is guided by detecting the reflectors using a laser radar or the like mounted on the automated guided vehicle.

Incidentally, accurate positioning is required for transporting a workpiece, and therefore high positioning accuracy is required for guiding an automated guided vehicle.
Although the magnetic guidance system, laser radar guidance system, or SLAM guidance system makes it possible to guide an unmanned guided vehicle even on a trackless road, there is room for improvement in terms of positioning accuracy when transporting a workpiece.
Patent Document 2, an example of prior art, discloses a positioning device that has a correction member such as a guide rail installed at a position corresponding to the stopping position in order to accurately position an unmanned guided vehicle at a stopping position.

JP 2019-128750 A JP 2015-178317 A

Here, a comparative example will be given to explain the problem to be solved by the present invention.
FIG. 3 is a top view showing an automated guided vehicle as a comparative example.
The automated guided vehicle shown in Figure 3 comprises a chassis 2 having a drive unit such as a motor, a guide roller unit 4 connected to the chassis 2, a steerable drive wheel 5 provided on the chassis 2, and driven wheels 6a, 6b provided on the guide roller unit 4.
A plurality of guide rollers are arranged on each of two side surfaces of the guide roller unit 4 that are not perpendicular to the traveling direction.
Specifically, guide rollers 7a1, 7a2, 7a3, and 7a4 are provided as multiple guide rollers on a first side portion, which is one of the two side portions not perpendicular to the traveling direction of the guide roller unit 4, and guide rollers 7b1, 7b2, 7b3, and 7b4 are provided as multiple guide rollers on a second side portion, which is the other of the two side portions not perpendicular to the traveling direction and faces the first side portion.
In the automatic guided vehicle shown in FIG. 3, guide roller unit 4 is fixed to chassis 2, guide rollers 7a1, 7a2, 7a3, and 7a4 contact guide rail 8a, and guide rollers 7b1, 7b2, 7b3, and 7b4 contact guide rail 8b, thereby correcting the traveling direction.

However, when an automatic guided vehicle having steered drive wheels as shown in FIG. 3 is subjected to correction using a track such as a guide rail, a reaction force is generated from the guide rail to the guide roller at the contact portion between the guide roller and the guide rail.
This reaction force corrects the direction of travel of the automated guided vehicle, but at this time, the two points of the guide roller that come into contact with the guide rail become the fulcrum and the point of force, and the drive wheel, which is located away, becomes the point of action, so due to the principle of leverage, a large load is placed on the guide rail.
Therefore, in the configuration of the comparative example, when the drive wheels skid, a large load is applied to the guide rail, or the guide rail may be damaged.

The present invention has been made in consideration of the above, and aims to provide a technology that prevents unreasonable skidding of the drive wheels, reduces the load on the guide rails, and enables smooth and highly accurate positioning, even for unmanned guided vehicles with steered drive wheels.

One aspect of the present invention that solves the above problems and achieves the object is an automated guided vehicle that has three or more wheels, a chassis, and a guide roller unit, the guide roller unit having multiple guide rollers that can rotate relative to the chassis on a running surface by a rotation mechanism, and the multiple guide rollers can slide on two guide rails arranged in parallel.

In the automated guided vehicle having the above configuration, the guide roller unit is locked against rotation relative to the chassis when the vehicle is traveling off-track, and the guide roller unit is unlocked from the chassis and allowed to rotate when the vehicle is guided along the track by the two guide rails.

The automated guided vehicle having the above configuration may further include steerable drive wheels provided on the chassis and driven wheels provided on the guide roller section connected to the chassis, and the multiple guide rollers are arranged on both side surfaces of the guide roller section, and one of the multiple guide rollers on both side surfaces slides along one side surface of the two guide rails, and the other of the multiple guide rollers on both side surfaces slides along the other side surface of the two guide rails.

The unmanned guided vehicle having the above configuration may further include a turntable section that overlaps with the guide roller section and rotates in conjunction with the rotation of the guide roller section.

According to the present invention, even in an automated guided vehicle with steered drive wheels, the drive wheels are prevented from skidding unnecessarily, the load on the guide rail is reduced, and positioning can be performed smoothly and with high precision.

FIG. 1A is a top view showing an automated guided vehicle according to the first embodiment, and FIG. 1B is a side view showing the automated guided vehicle according to the first embodiment. FIG. 2 is a top view showing a guide rail used for positioning the automatic guided vehicle shown in FIG. FIG. 3 is a top view showing an automated guided vehicle as a comparative example. FIG. 4A is a diagram showing an automatic guided vehicle in a locked state, and FIG. 4B is a diagram showing an automatic guided vehicle in an unlocked state. FIG. 5(A) is a top view showing an example of contact between the guide roller and the rail, and FIG. 5(B) is a top view showing an example of contact between the guide roller and the rail after the guide roller portion has advanced. FIG. 6 is a diagram showing an automated guided vehicle that is a first modified example of the automated guided vehicle according to the first embodiment. FIG. 7 is a diagram showing an automatic guided vehicle which is a second modified example of the automatic guided vehicle according to the first embodiment. FIG. 8 is a side view showing an automated guided vehicle according to the second embodiment. FIG. 9 is a diagram showing an outline of the guide roller unit as viewed from above and an outline of the turntable unit as viewed from behind in the automated guided vehicle according to the second embodiment. FIG. 10 is a top view showing a design example of the turntable unit in the second embodiment. FIG. 11 is a top view showing a design example of the guide roller portion in the second embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
However, the present invention should not be construed as being limited to the following embodiments.

(Embodiment 1)
FIG. 1A is a top view showing an automated guided vehicle 1 according to this embodiment, and FIG. 1B is a side view showing the automated guided vehicle 1 according to this embodiment.
The unmanned guided vehicle 1 shown in Figures 1(A) and (B) comprises a chassis 2 having a drive unit such as a motor, a laser navigation system 3 used in a laser radar guidance system, a guide roller unit 4 rotatably connected to the chassis 2, a steerable drive wheel 5 provided on the chassis 2, and driven wheels 6a, 6b provided on the guide roller unit 4.
The guide roller portion 4 is provided with a rotation mechanism that rotates about the center of the wheel shaft of the driven wheels 6a and 6b.
The guide roller unit 4 can rotate relative to the chassis 2 on the running surface of the automated guided vehicle 1 by the rotation mechanism, and a workpiece or a transfer device is provided on the guide roller unit 4 depending on the application of the automated guided vehicle 1.
Further, a plurality of guide rollers are arranged on each of two side surfaces of the guide roller unit 4 that are not perpendicular to the moving direction.
Specifically, guide rollers 7a1, 7a2, 7a3, and 7a4 are provided as multiple guide rollers on a first side portion, which is one of the two side portions not perpendicular to the traveling direction of the guide roller unit 4, and guide rollers 7b1, 7b2, 7b3, and 7b4 are provided as multiple guide rollers on a second side portion, which is the other of the two side portions not perpendicular to the traveling direction and faces the first side portion.

FIG. 2 is a top view showing the guide rail 8 used for positioning the automatic guided vehicle 1 shown in FIG.
The guide rail 8 shown in Figure 2 guides the unmanned transport vehicle 1 along each sliding surface between rails 8a and 8b arranged in parallel, making it possible to guide the unmanned transport vehicle 1 to a stopping position while adjusting the left-right position and angle of the unmanned transport vehicle 1.
Guide rollers 7a1, 7a2, 7a3, and 7a4 slide along rail 8a, and guide rollers 7b1, 7b2, 7b3, and 7b4 slide along rail 8b, with the sliding surface of rail 8a and the sliding surface of rail 8b facing each other.
As shown in FIG. 2, a car stopper 9a may be provided at the innermost portion of the rail 8a, and a car stopper 9b may be provided at the innermost portion of the rail 8b.
The unmanned guided vehicle in this embodiment estimates its own position using guidance control such as a laser radar guidance system, a SLAM guidance system, a magnetic guidance system, etc., and stops at a predetermined position. However, by providing car stops 9a, 9b, even if there is a deviation from the estimated self-position, it is possible to ensure that the vehicle will stop at the predetermined position without exceeding the stopping positions of the car stops 9a, 9b.
However, the present invention is not limited to this, and the wheel stops 9a, 9b do not necessarily have to be provided on the rails 8a, 8b.

When the automated guided vehicle 1 shown in FIG. 1 travels on a surface on which no guide rail 8 is provided, i.e., when the automated guided vehicle 1 travels off-track, the guide roller portion 4 is fixed so as not to rotate and is in a locked state.
On the other hand, when the unmanned guided vehicle 1 shown in Figure 1 runs on a running surface on which the guide rails 8 are provided, i.e., during track guidance, the guide roller unit 4 is unlocked and becomes rotatable relative to the chassis 2.

FIG. 4A is a diagram showing the automated guided vehicle 1 in a locked state, and FIG. 4B is a diagram showing the automated guided vehicle 1 in an unlocked state.
The rollers 10a and 10b, the roller support portions 11c and 11b, the power cylinder 12 and the trapezoidal block 13 shown in FIG.
The power cylinder 12 and the trapezoidal block 13 may be provided within the chassis 2 .
As shown in FIG. 4A, during trackless travel, the power cylinder 12 presses the trapezoidal block 13 against the rollers 10a and 10b provided in the guide roller unit 4, thereby entering a locked state and restricting the rotation of the guide roller unit 4.
The roller 10a is supported on the guide roller portion 4 by a roller support portion 11a, and the roller 10b is supported on the guide roller portion 4 by a roller support portion 11b.
At this time, if the angle of the guide roller portion 4 with respect to the chassis 2 is misaligned, an adjustment is made so that the angle misalignment becomes smaller.

As shown in FIG. 4B, when the trackless automated guided vehicle 1 travels with the guide roller portion 4 side facing forward and the guide roller 7a4 reaches the rail 8a or the guide roller 7b4 reaches the rail 8b, the power cylinder 12 stops pushing the trapezoidal block 13, releases the locked state, and pulls the trapezoidal block 13 toward the power cylinder 12.
This allows the guide roller portion 4 to rotate relative to the chassis 2 .
However, to prevent the angle of the guide roller portion 4 relative to the chassis 2 from changing significantly, the rotation of the guide roller portion 4 relative to the chassis 2 is restricted within a predetermined angle range by rollers 10a and 10b.
Here, the predetermined angle range is, for example, ±5°.
The guide roller unit 4 is locked and unlocked at a predetermined position by estimating its own position using guidance control such as a laser radar guidance system, a SLAM guidance system, or a magnetic guidance system.
In addition, contact of the guide roller 7a4 with the rail 8a and contact of the guide roller 7b4 with the rail 8b may be detected by a sensor or the like (not shown).
Furthermore, the trapezoidal block 13 is not limited to the form shown in the drawings, and may have any configuration as long as it is capable of switching between a locked state and an unlocked state in cooperation with the rollers 10a, 10b.

Figure 5 (A) is a top view showing an example of contact between guide roller 7b4 and rail 8b, and Figure 5 (B) is a top view showing an example of contact between guide roller 7b4 and rail 8b and guide roller 7a4 and rail 8a after guide roller unit 4 has progressed.
As shown in Figure 5 (A), when the guide roller 7b4 contacts the rail 8b while there is a left-right misalignment in the direction of travel, the guide roller portion 4 rotates relative to the chassis 2, the driven wheels 6a and 6b run so as to reduce the left-right misalignment, and the guide roller portion 4 moves toward the center between the rails 8a and 8b.

As shown in Figure 5 (B), when the guide roller portion 4 is guided so that the guide roller 7a3 comes into contact with the rail 8a and the guide roller 7b3 comes into contact with the rail 8b, the driven wheels 6a and 6b perform a lateral sliding motion to adjust the angle deviation of the automatic guided vehicle 1 to be reduced.
However, the load on the driven wheels 6a and 6b is smaller than the load on the driving wheels 5, and the point of force and the point of action are close, so the load caused by the skid of the driven wheels 6a and 6b on the rails 8a, 8b is small.

In addition, by adjusting the left-right and angle misalignment of the guide roller unit 4, the left-right and angle misalignment of the work or transfer device (not shown) installed on the guide roller unit 4 is also adjusted to be small along the rails 8a and 8b.

In addition, because of the rotation mechanism of the guide roller unit 4, the automated guided vehicle 1 turns in accordance with the left and right movement of the guide roller unit 4, so no movement that causes the drive wheels 5 to skid sideways occurs.

In this embodiment, an unmanned guided vehicle having one drive wheel and two driven wheels has been described, but the present invention is not limited to this, and it is sufficient if three or more wheels are provided in total, including the drive wheel and the driven wheels, to enable the vehicle to stand on its own.
The unmanned transport vehicle 1 may have three or more wheels, a chassis 2 and a guide roller unit 4, and the guide roller unit 4 may have a plurality of guide rollers, be rotatable relative to the chassis on the running surface by a rotation mechanism, and be capable of sliding on two guide rails on which the plurality of guide rollers are arranged in parallel.

As described above, the automated guided vehicle according to this embodiment may be provided with three or more wheels, including the drive wheels and the driven wheels.
FIG. 6 is a diagram showing an automatic guided vehicle 1a which is a first modified example of the automatic guided vehicle according to this embodiment.
The automated guided vehicle 1 a shown in FIG.

In this embodiment, a configuration has been shown in which a plurality of guide rollers are arranged on each of the two side surfaces of the guide roller unit 4 that are not perpendicular to the traveling direction, but the present invention is not limited to this.
FIG. 7 is a diagram showing an automatic guided vehicle 1b which is a second modified example of the automatic guided vehicle according to this embodiment.
As shown in FIG. 7, two guide rollers may be disposed on one side of the guide roller unit 4 that is not perpendicular to the traveling direction.
An automated guided vehicle 1b shown in FIG. 7 includes guide rollers 7b1 and 7b4 on the second side surface of the guide roller unit 4.

In this embodiment, a configuration including one chassis 2 and one guide roller portion 4 has been described, but the present invention is not limited to this, and two guide roller portions 4 may be provided.
In other words, the two guide roller portions 4 may be configured to sandwich the chassis 2 therebetween.

According to this embodiment, the rotation of the guide roller portion serves as the center of rotation (i.e., the fulcrum) when correcting the direction of travel of the automated guided vehicle, and the distance between the force point and the point of action becomes closer. This means that even in an automated guided vehicle with steered drive wheels, the load on the guide rail can be reduced without causing the drive wheels to skid unnecessarily, and positioning can be performed smoothly and with high precision.

(Embodiment 2)
In this embodiment, a configuration in which a further element is added to the first embodiment will be described.
FIG. 8 is a side view showing an automatic guided vehicle 1c according to this embodiment.
An automated guided vehicle 1c shown in FIG. 8 differs from the automated guided vehicle 1 of the first embodiment in that it includes a fork portion 20 that can be raised and lowered, but other configurations are the same as those of the automated guided vehicle 1.
The fork portion 20 is disposed at a position overlapping the guide roller portion 4, and a turntable portion 21 is provided at one end of the fork portion 20.
A workpiece or a transfer device is placed on the turntable portion 21 depending on the application of the automatic guided vehicle 1c.
The automatic guided vehicle 1c is configured so that the fork portion 20 can raise and lower the workpiece or the transfer device.
The guide roller unit 4 and the turntable unit 21 are connected by a wire 22 .

FIG. 9 is a diagram showing an outline of the guide roller unit 4 as viewed from above and an outline of the turntable unit 21 as viewed from behind in an automated guided vehicle 1c according to this embodiment.
As shown in FIG. 9, the upper surface of the guide roller portion 4 and the rear surface of the turntable portion 21 are connected by two crossed outer wires 22 .
As a result, when the guide roller portion 4 rotates, the turntable portion 21 rotates in the same direction as the guide roller portion 4 and at approximately the same angle.
In addition, the wire 22 may be in contact with the idle roller 23 , and the idle roller 23 may be supported by an idle roller support portion 24 .

FIG. 10 is a top view showing a design example of the turntable unit 21 in this embodiment, and FIG. 11 is a top view showing a design example of the guide roller unit 4 in this embodiment.
The rotation of the turntable unit 21 shown in FIG. 10 is restricted by a stopper 25 so as to be within a predetermined angle range.
Here, the predetermined angle range is, for example, ±7°.
The rotation of the guide roller portion 4 shown in FIG. 11 is restricted to a predetermined angle range as described with reference to FIG. 4B in the first embodiment.
Here, the predetermined angle range is, for example, ±5°, as described above.
One end of the wire 22 is fixed to the wire fixed end shown in FIG. 10, and the other end of the wire 22 is fixed to the wire fixed end shown in FIG.
The outer of the wire 22 is fixed to the outer fixing portion.

As described above, by making the angular range of the turntable unit 21 larger than the angular range of the guide roller unit 4, the load on the wire 22 can be reduced.
However, if the angle range of the turntable portion 21 is made excessively large, the turntable portion 21 may rotate significantly when the wire 22 is cut, which may result in collision with structures around the automatic guided vehicle 1.
Therefore, a preferable rotation angle range of the turntable portion 21 is illustrated as ±7° here.

As shown in FIG. 10, an idle roller 23 for maintaining tension of the wire 22 and an idle roller support portion 24 for supporting the idle roller 23 are disposed near the turntable portion 21 .
With this configuration, when the wire 22 is cut, the idle roller 23 jumps out, and a sensor (not shown) detects this jumping out, making it possible to automatically stop the automated guided vehicle 1.

Furthermore, on the pushing side of the idle roller 23, the position is adjusted so that the wire 22 makes a slight movement, for example a movement of 1 mm, so that it comes into contact with a stopper (not shown). During operation, the idle roller 23 moves significantly due to the difference in tension between the two wires 22, thereby reducing synchronization errors between the top and bottom.
In addition, the wire 22 is tensioned by applying a constant pressure. This is to increase the rigidity of the wire 22 by applying tension to the wire 22 in advance, reduce synchronization errors, and prevent the wire 22 from breaking due to being over-tensioned.

In addition to the effects of embodiment 1, this embodiment makes it possible to raise and lower the workpiece or the transfer device, and to link the guide roller section and the turntable section.

The present invention is not limited to the above-described embodiment, but also includes various modifications in which components are added, deleted, or converted from the above-described configuration.

Reference Signs List 1, 1a, 1b, 1c Automatic guided vehicle 2 Chassis 3 Laser navigation 4 Guide roller section 5, 5a, 5b Driving wheels 6, 6a, 6b Driven wheels 7a1, 7a2, 7a3, 7a4, 7b1, 7b2, 7b3, 7b4 Guide roller 8 Guide rail 8a, 8b Rail 9a, 9b Wheel stopper 10a, 10b Roller 11c, 11b Roller support section 12 Power cylinder 13 Trapezoidal block 20 Fork section 21 Turntable section 22 Wire 23 Idle roller 24 Idle roller support section 25 Stopper

Claims (3)

An automated guided vehicle having three or more wheels, a chassis, and a guide roller unit,
the guide roller unit includes a plurality of guide rollers and a roller supported by the guide roller unit , and is rotatable relative to the chassis on a running surface by a rotation mechanism;
the chassis includes a movable block that can be pushed against the roller, and a cylinder that moves the movable block;
The plurality of guide rollers are slidable on two guide rails arranged in parallel,
The cylinder is
During trackless travel, the movable block is pushed in and brought into contact with the roller, thereby locking the rotation of the guide roller portion relative to the chassis;
The automatic guided vehicle unlocks the guide roller portion relative to the chassis by stopping pushing of the movable block during trajectory guidance by the two guide rails . steerable drive wheels provided on the chassis;
a driven wheel provided on the guide roller portion connected to the chassis;
The plurality of guide rollers are disposed on both side surfaces of the guide roller portion,
One of the guide rollers on both sides of the plurality of guide rollers slides along one side of the two guide rails,
2. The automated guided vehicle according to claim 1, wherein the other of the plurality of guide rollers on both side surfaces slides along the other side surface of the two guide rails. The automated guided vehicle according to claim 1 or 2 , further comprising a turntable portion overlapping the guide roller portion and rotating in conjunction with rotation of the guide roller portion.

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