Automatic conveying device

Abstract

To change the direction of an article to be conveyed while securing a facility space by minimizing a space for automatic conveyance in the case of conveying a plurality of automatic conveying vehicles in a connected state.SOLUTION: This automatic conveying device 10 is provided with a plurality of automatic conveying vehicles 11 and 12 capable of traveling autonomously on a predetermined line L, a connecting body 13 for mutually connecting the plurality of automatic conveying vehicles 11 and 12, and control parts 15a and 15b capable of controlling the traveling of each automatic conveying vehicle 11 and 12. Each of the automatic guided vehicles 11 and 12 is coupled to the coupling body 13 so as to be rotatable about a predetermined vertical axis, and the control units 15a and 15b are configured to control traveling of each of the automatic guided vehicles 11 and 12 so that the rear automatic guided vehicle 12 coupled to the front automatic guided vehicle 11 via the coupling body 13 moves toward a position deviated from the predetermined line L while the front automatic guided vehicle 11 among the plurality of automatic guided vehicles 11 and 12 travels on the predetermined line L.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an automatic transport device. [Background technology]

[0002] 2. Description of the Related Art In production sites such as factories, automatic guided vehicles (AGVs, also called unmanned guided vehicles) are used to transport parts, intermediate products, or finished products in order to improve productivity by saving labor.

[0003] In addition, when performing the above-mentioned automatic transport, a method is known in which a cart loaded with parts is towed by one automatic transport vehicle (see Patent Document 1), and a method is known in which the object to be transported is transported by two automatic transport vehicles (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4877520 [Patent Document 2] Patent No. 6151159 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, when considering the cooperative transport of a specific object by two automated guided vehicles, one possible approach is to couple the automated guided vehicles to a carriage unit, such as a pallet, on which the object can be mounted, and control both automated guided vehicles to move along the line at the same speed while detecting a common line. On the other hand, if the two automated guided vehicles need to be stopped at a target position while changing the alignment direction of the two automated guided vehicles to a different direction (e.g., perpendicular direction) from the alignment direction during travel in order to orient the object according to a process or equipment, as shown in FIG. 7 , in an automated transport system using two automated guided vehicles 111 and 112 that both travel along a line L and are connected to each other by a connector 113, it is necessary to curve the line L itself just before the target position and change the direction of the line L so that the two automated guided vehicles 111 and 112 are aligned in the target direction. To minimize the space required for automated transport, the radius of curvature of the curve section Lc should be minimized. However, the applicable radius of curvature is limited by the minimum turning radius that the two automated guided vehicles 111 and 112 can adopt. This means that the space required for automatic transport cannot be made small enough, resulting in a shortage of equipment space.

[0006] The above-mentioned problem is not limited to a transport system in which two automated guided vehicles are linked together, but can also occur in a transport system in which, for example, three or more automated guided vehicles are linked together.

[0007] In view of the above circumstances, the technical problem to be solved in this specification is to make it possible to change the orientation of the transported object while minimizing the space required for automatic transport and securing equipment space when transporting objects using multiple connected automatic transport vehicles. [Means for solving the problem]

[0008] The above-mentioned problems are solved by an automated guided vehicle according to the present invention. Specifically, this automated guided vehicle comprises a plurality of automated guided vehicles, each capable of autonomously traveling on a predetermined line, a connecting member connecting the plurality of automated guided vehicles to each other, and a control unit capable of controlling the traveling of each automated guided vehicle, and is capable of transporting an object through cooperation of the plurality of automated guided vehicles, wherein each automated guided vehicle is connected to the connecting member so as to be rotatable about a predetermined vertical axis, and the control unit is configured to control the traveling of each automated guided vehicle so that the frontmost automated guided vehicle among the plurality of automated guided vehicles travels on the predetermined line, while a rearward automated guided vehicle connected to the front automated guided vehicle via the connecting member moves toward a position off the predetermined line.

[0009] As described above, in the present invention, multiple automated guided vehicles are all capable of autonomous travel and are connected to each other by a connector, and each automated guided vehicle is connected to the connector so that it can rotate about a predetermined vertical axis. The travel of each automated guided vehicle can be controlled so that the frontmost automated guided vehicle travels on a predetermined line while the rear automated guided vehicle, which is connected to the front automated guided vehicle via the connector, moves toward a position off the predetermined line. Therefore, without providing a curved section in the line to change the direction of the transported object, the front automated guided vehicle and the rear automated guided vehicle can be lined up in a desired direction by making the autonomously traveling rear automated guided vehicle travel in a different manner from the front automated guided vehicle. This makes it possible to change the direction of the transported object as desired while minimizing the space required for each automated guided vehicle to travel.

[0010] In addition, in the automatic transport device of the present invention, when the rear automatic transport vehicle is moved so that the alignment direction of the front automatic transport vehicle and the rear automatic transport vehicle is changed from a direction along the line to a direction that intersects with the line, the control unit may be configured to be able to control the speed of the rear automatic transport vehicle and the turning angle of the rear automatic transport vehicle relative to the connecting part based on the turning angle of the front automatic transport vehicle relative to the connecting part.

[0011] As described above, when multiple automated guided vehicles are interconnected by a connector, and each automated guided vehicle is connected to the connector so that it can rotate around a predetermined vertical axis, the rotation angle of the front automated guided vehicle traveling on a predetermined line relative to the connector reflects the position of the rear automated guided vehicle. Therefore, when considering controlling the trajectory of the rear automated guided vehicle using the rotation angle and speed, by setting the rotation angle and speed values ​​based on the rotation angle of the front automated guided vehicle, the rear automated guided vehicle can rotate around the traveling front automated guided vehicle along an appropriate trajectory even if it is located off the line. Therefore, compared to, for example, when the front automated guided vehicle 111 is stopped at a predetermined position on line L and only the rear automated guided vehicle 112 is rotated (see FIG. 8), it is possible to change the alignment direction in a shorter time.

[0012] Furthermore, when controlling the turning speed and velocity as described above, the control unit may be configured to be able to control the speed and turning angle of the rear automatic guided vehicle by applying different turning angle formulas for a first turning state in which the rear automatic guided vehicle turns and moves toward one of the left and right sides, and a second turning state in which the rear automatic guided vehicle turns and moves toward the other of the left and right sides, when the target position of the rear automatic guided vehicle is located on either the left or right side of the direction of travel of the front automatic guided vehicle.

[0013] By switching the turning direction midway as described above, the front automated guided vehicle can travel along the line at a constant speed, while the rear automated guided vehicle can be moved a short distance to a position where it changes its alignment direction with the front automated guided vehicle. Furthermore, in this case, by applying different equations for the turning angle before and after switching the turning direction, it is possible to accurately calculate the speed and turning velocity appropriate for each turning state. Therefore, this control mode makes it possible to accurately move the rear automated guided vehicle toward the target position.

[0014] Furthermore, when the turning speed and velocity are controlled as described above, each automated guided vehicle may have a pair of wheels and a drive unit capable of independently driving each wheel, and the control unit may be configured to set the turning radius of the rear automated guided vehicle based on the turning angle of the front automated guided vehicle, and to control the rotation speed of each wheel based on the set turning radius.

[0015] As described above, when each automated guided vehicle is configured to be able to turn based on the difference in the rotation speed of a pair of independently driven wheels, the turning radius of the rear automated guided vehicle can be set based on the turning angle of the front automated guided vehicle, and the rotation speed of each wheel can be controlled based on the set turning radius, thereby directly and accurately setting the turning movement of the rear automated guided vehicle. Using the turning radius as a control parameter in this way allows the rotation speed of each wheel to be directly controlled, which allows for more direct and accurate control of turning movement than, for example, detecting the turning angle and feedback-controlling the turning angle so that the detected value approaches a set value for the turning angle. In this case, depending on the conditions, even if the turning angle is excluded from the control targets, the movement of the rear automated guided vehicle can be controlled without any problems by setting only the remaining parameters (speed and the rotation speed of each wheel calculated from the turning radius). [Effects of the Invention]

[0016] As described above, with the automatic conveying device of the present invention, when conveying goods using multiple connected automatic conveying vehicles, it is possible to minimize the space required for automatic conveying, thereby securing equipment space, while also making it possible to change the orientation of the automatic conveying device and, therefore, the orientation of the goods being conveyed. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a plan view of an automatic conveying device according to an embodiment of the present invention. [Figure 2] This figure explains the control mode when the automatic transport device shown in Figure 1 changes the alignment direction of two automatic transport vehicles, and shows the state in which the rear automatic transport vehicle has turned to one of the left and right sides from a state in which the front and rear automatic transport vehicles are lined up along the line (at the end of the first turning state). [Figure 3] FIG. 2 is a diagram for explaining the control mode when the automatic transport device shown in FIG. 1 changes the alignment direction of two automatic transport vehicles, and shows the state (at the end of the second turning state) in which the rear automatic transport vehicle has changed its turning direction from one side to the other and then moved to a position where they are lined up in a direction perpendicular to the line. [Figure 4] 2 is a diagram conceptually showing the relationship between the turning radius and the inner wheel difference of the automatic guided vehicle shown in FIG. 1. FIG. [Figure 5] 10 is a graph showing an example of a history of turning angles of the front and rear automated guided vehicles according to the present invention. [Figure 6] 10 is a graph showing an example of speed history of the front and rear automated guided vehicles according to the present invention. [Figure 7] 10A and 10B are diagrams for explaining an example of a control mode when an automatic conveying device according to a comparison with the present invention changes the arrangement direction. [Figure 8] 10A and 10B are diagrams for explaining another example of a control mode when an automatic conveying device according to a comparison with the present invention changes an arrangement direction. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, the details of an automatic conveying device according to one embodiment of the present invention will be described with reference to the drawings.

[0019] 1 shows a plan view of an automatic guided vehicle 10 according to one embodiment of the present invention. This automatic guided vehicle 10 mainly includes two automatic guided vehicles 11 and 12, a connecting member 13 that connects the two automatic guided vehicles 11 and 12 to each other, angle detection units 14a and 14b that can detect the angles of the rotation directions of each automatic guided vehicle 11 and 12 relative to the connecting member 13 (hereinafter referred to as rotation angles θf and θr), and control units 15a and 15b.

[0020] In this embodiment, the automated guided vehicle 10 further includes speed detection units 16a and 16b, and communication units 17a and 17b, which are capable of detecting the speeds Vf and Vr of the automated guided vehicles 11 and 12. Each element will be described in detail below.

[0021] Both automated guided vehicles 11 and 12 have a structure that allows them to travel autonomously on a predetermined line L, and include, for example, a pair of wheels 18a and 18b and a pair of drive sources 19a and 19b that apply rotational drive force to each of wheels 18a and 18b. In this case, by making the rotation speeds of each wheel 18a and 18b equal, automated guided vehicles 11 and 12 travel straight, and by making the rotation speeds of each wheel 18a and 18b different, automated guided vehicles 11 and 12 can turn toward the wheel with the lower rotation speed of the pair of wheels 18a and 18b.

[0022] The connecting body 13 integrally includes a loading section 20, which is, for example, pallet-shaped and capable of loading an object to be transported (not shown), a first connecting section 21 located in front of the loading section 20 for connecting to one of the automated guided vehicles 11, and a second connecting section 22 located in the rear of the loading section 20 for connecting to the other automated guided vehicle 12. In this embodiment, the first connecting section 21 protrudes forward from the loading section 20, and a connecting shaft 23 provided on one of the automated guided vehicles 11 and extending vertically upward is fitted into a connecting hole 21a provided in the first connecting section 21. As a result, the one automated guided vehicle 11 is connected to the connecting body 13 and is capable of rotating relative to the connecting body 13 around (the central axis of) the connecting shaft 23. The second connecting portion 22 projects rearward from the mounting portion 20, and a connecting shaft 24 provided on the other automated guided vehicle 12 and extending vertically upward is fitted into a connecting hole 22a provided in the second connecting portion 22. This allows the other automated guided vehicle 12 to be connected to the connecting body 13 and to rotate around (the central axis of) the connecting shaft 24 relative to the connecting body 13.

[0023] Although not shown, the mounting unit 20 is provided with a plurality of wheels, which allow the connecting body 13 to follow the movement of the automatic guided vehicles 11 and 12. In this case, each wheel is configured to be rotatable about a vertical axis.

[0024] Angle detection units 14a, 14b are configured with, for example, known angle sensors, and are disposed at or near the connection portion between each automated guided vehicle 11, 12 and connected body 13. This makes it possible to detect the turning angles θf, θr of each automated guided vehicle 11, 12 relative to connected body 13. In the following description, for convenience, one automated guided vehicle 11 will be referred to as the front automated guided vehicle 11, and the other automated guided vehicle 12 will be referred to as the rear automated guided vehicle 12.

[0025] The speed detection units 16a, 16b are capable of detecting the speeds Vf, Vr of the respective automated guided vehicles 11, 12, and are configured, for example, with known speed sensors. In this embodiment, a first speed detection unit 16a is provided on the front automated guided vehicle 11, and a second speed detection unit 16b is provided on the rear automated guided vehicle 12. This makes it possible to detect the speed Vf of the front automated guided vehicle 11 and the speed Vr of the rear automated guided vehicle 12.

[0026] The communication units 17a and 17b are configured to be able to transmit predetermined information acquired by each of the automated guided vehicles 11 and 12 to the corresponding control units 15a and 15b. In this embodiment, the front automated guided vehicle 11 is provided with a first angle detection unit 14a, a first speed detection unit 16a, a first communication unit 17a, and a first control unit 15a, and is configured to be able to transmit the turning angle θf of the front automated guided vehicle 11 detected by the first angle detection unit 14a and the speed Vf of the front automated guided vehicle 11 detected by the first speed detection unit 16a to the first control unit 15a via the first communication unit 17a. In addition, the rear automatic guided vehicle 12 is provided with a second angle detection unit 14b, a second speed detection unit 16b, a second communication unit 17b, and a second control unit 15b, and is configured so that the rotation angle θr of the rear automatic guided vehicle 12 detected by the second angle detection unit 14b and the speed Vr of the rear automatic guided vehicle 12 detected by the second speed detection unit 16b can be transmitted to the second control unit 15b via the second communication unit 17b.

[0027] In addition, in this embodiment, the first communication unit 17a and the second communication unit 17b are capable of bidirectional communication, and the rotation angle θf detected by the first angle detection unit 14a is configured to be transmittable to the second control unit 15b via the first communication unit 17a and the second communication unit 17b, and the rotation angle θr detected by the second angle detection unit 14b is configured to be transmittable to the first control unit 15a via the second communication unit 17b and the first communication unit 17a.

[0028] Each of the control units 15a and 15b is capable of controlling the travel of the corresponding automated guided vehicles 11 and 12. Specifically, each of the automated guided vehicles 11 and 12 is provided with a line detection unit (not shown) capable of detecting the line L, and is configured to control the movement of each of the automated guided vehicles 11 and 12 so that each of the automated guided vehicles 11 and 12 is positioned on the line L (without deviating from the line L) based on position information regarding the line L detected by the line detection unit. Specifically, each of the control units 15a and 15b is configured to control the rotation speed (more precisely, the difference in the rotation speed) of the pair of wheels 18a and 18b so as to satisfy the above-mentioned conditions. In this case, the first control unit 15a controls the movement of the front automated guided vehicle 11 so that the front automated guided vehicle 11 is always positioned on the line L, whereas the second control unit 15b is capable of controlling the movement of the rear automated guided vehicle 12 so that the rear automated guided vehicle 12 moves toward a position off the line L under predetermined conditions.

[0029] To explain in detail the control when moving to a position off the line, the second control unit 15b is configured to be able to control the speed Vr and turning angle θr of the rear automatic guided vehicle 12, which is the control target, based on the turning angle θf of the front automatic guided vehicle 11, which is not the control target.

[0030] In this embodiment, the second control unit 15b is further configured to set the turning radius R of the rear automatic guided vehicle 12 based on the turning angle θf of the front automatic guided vehicle 11, and to control the difference in rotation speed between the pair of wheels 18a, 18b (i.e., the rotation speed of each wheel 18a, 18b) based on the set turning radius R.

[0031] In this case, the second control unit 15b is configured to be able to switch the control mode of the rear-side automated guided vehicle 12 in accordance with the traveling state of each of the automated guided vehicles 11, 12. Specifically, the second control unit 15b is configured to control (set) the speed Vr, turning angle θr, and turning radius R of the rear-side automated guided vehicle 12 by applying different equations for the turning angle θf in a state in which the rear-side automated guided vehicle 12 is turning in a predetermined direction toward a position off the line (first turning state shown in FIG. 2) from a state in which the front-side automated guided vehicle 11 and the rear-side automated guided vehicle 12 are both traveling on the line L, and a state in which the turning direction is switched to the opposite direction after the rear-side automated guided vehicle 12 has turned in the predetermined direction to a certain extent, and the rear-side automated guided vehicle 12 is moved to a position where the arrangement direction of the front and rear automated guided vehicles 11, 12 is changed (second turning state shown in FIG. 3).

[0032] An example of the control flow will be described in detail below. First, the turning angle θf of the front automated guided vehicle 11 while traveling is detected, and if the conditional expression represented by the following mathematical expression 1 is satisfied when the value of the detected turning angle θf is substituted, the rear automated guided vehicle 12 is deemed to be in a first turning state, and the second control unit 15b selects the control mode represented by mathematical expressions 2 to 4 (first control mode) and sets the values ​​of the speed Vr, turning angle θr, and turning radius R. Note that in mathematical expressions 1 to 8 shown below, the values ​​of each turning angle θf, θr are both set to 90 degrees (π / 2 rad) when traveling in a straight line, and the positive and negative directions of each turning angle θf, θr are determined so that the phase advances counterclockwise as in the illustrated example (see FIG. 1, etc.).

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[0033] Alternatively, if the conditional expression expressed by the following formula 5 is satisfied when the value of the detected turning angle θf is substituted, the second control unit 15b determines that the rear automatic guided vehicle 12 is in the second turning state, selects the control mode expressed by formulas 6 to 8 (second control mode), and sets the values ​​of the speed Vr, turning angle θr, and turning radius R.

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[0034] Here, V0 is the speed of each automated guided vehicle 11, 12 on the line, and while the rear automated guided vehicle 12 moves off line L, the front automated guided vehicle 11 is controlled to travel on line L at a constant speed V0. Also, α1, α2, β1, β2, γ, δ, ε, ζ, and η are coefficients set based on the distance D (see Figure 1) between the connecting points Pf and Pr of the connecting body 13 and each automated guided vehicle 11, 12, and are set to appropriate values ​​depending on the value of distance D, for example, when distance D is determined within a range in which an object of a size such as an automobile body can be carried.

[0035] When the value of speed Vr is set as described above, second control unit 15b controls the rotation speed of each of wheels 18a, 18b so that the value of speed Vr becomes the value set based on Formula 2 or Formula 6. When speed detection unit 16b is provided on the rear automated guided vehicle 12 as in this embodiment, if the speed Vr detected by speed detection unit 16b differs from the value of speed Vr set based on Formula 2 or Formula 6 (if the speed difference is equal to or greater than a certain number), speed Vr may be corrected (feedback controlled) so that the speed difference approaches zero.

[0036] Furthermore, when the value of the turning angle θr is set as described above, the second control unit 15b controls the difference in the rotation speed between the pair of wheels 18a, 18b so that the value of the turning angle θr becomes the value set based on Formula 3 or Formula 7. When the angle detection unit 14b is provided on the rear automated guided vehicle 12 as in this embodiment, if the turning angle θr detected by the angle detection unit 14b differs from the value of the turning angle θr set based on the above-mentioned Formula 3 or Formula 7 (if the difference is equal to or greater than a certain number), the turning angle θr may be corrected (feedback controlled) so that the angle difference approaches zero.

[0037] Furthermore, when the value of turning radius R is set as described above, second control unit 15b controls the difference in the rotation speeds of the pair of wheels 18a, 18b so that the value of turning radius R becomes the value set based on Equation 4 or Equation 8. Here, as shown in FIG. 4, if turning radius R is considered to be the distance from arc Ac passing through widthwise center Pc of automated guided vehicle 12 to turning center O, the turning radius of the wheel farther from turning center O (left wheel 18a in FIG. 4) is equal to the distance from arc Aw1 passing through widthwise center Pw1 of wheel 18a to turning center O, and can be expressed as R+d / 2, where d is the distance between wheels 18a, 18b. Similarly, the turning radius of wheel 18b closer to turning center O is equal to the distance from arc Aw2 passing through widthwise center Pw2 of wheel 18b to turning center O, and can be expressed as Rd / 2. Therefore, when the rotation speeds of the wheels 18a and 18b are n1 and n2, respectively, the rotation speeds n1 and n2 can be calculated as the equation for the turning radius R based on the following formulas 9 and 10. Note that n0 is the rotation speed of the wheel that is virtually in contact with the ground at the center Pc in the width direction.

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[0038] Next, one mode of control when changing the alignment direction of the two automatic guided vehicles 11, 12 that make up the automatic guided vehicle 10 configured as described above from the direction along the line L to the direction perpendicular to that direction will be described with reference to Figures 2 to 6. Note that in Figures 2 and 3, the shape of the connecting body 13 is simplified to a rod-like body to show that the connecting body 13 is a rigid body and to make it easier to understand the rotation angles θf and θr.

[0039] First, as shown in FIG. 2, when the automated guided vehicle 10 reaches a predetermined position on the line L, the front automated guided vehicle 11 continues traveling on the line L at a constant speed V0, while the rear automated guided vehicle 12 starts turning toward a position where it will leave the line L (first turning state). The turning direction at this time is set to either the left or right side (the right side in the illustrated example) where the target position is located relative to the traveling direction of the front automated guided vehicle 11 (here, the upward direction along the line L). In this state where the rear automated guided vehicle 12 has left the line L and started turning (first turning state), the second control unit 15b selects the first control mode and controls the speed Vr, turning angle θr, and turning radius R of the rear automated guided vehicle 12 based on Equations 2 to 4. More precisely, the rotation speeds n1 and n2 of the wheels 18a and 18b are controlled so that the speed Vr, turning angle θr, and turning radius R all become set values.

[0040] In this case, in the first traveling state, the turning angle θr of the rear automated guided vehicle 12 changes (here, decreases) ahead of the turning angle θf of the front automated guided vehicle 11 (see FIG. 5). Also, while the speed Vf of the front automated guided vehicle 11 is constant at speed V0, the speed Vr of the rear automated guided vehicle 12 increases exponentially (see FIG. 6). As a result, the rear automated guided vehicle 12 follows the front automated guided vehicle 11 while turning.

[0041] Then, when the rear automated guided vehicle 12 approaches the front automated guided vehicle 11 while turning to a certain position (for example, when the turning angle θf reaches 60°), the rear automated guided vehicle 12 switches its turning direction from one of the left and right sides to the other of the left and right sides (leftward in this case) and continues turning (see FIG. 3). In this state (second turning state) in which the rear automated guided vehicle 12 moves until it reaches the target position after switching its turning direction, the second control unit 15b selects the second control mode and controls the speed Vr, turning angle θr, and turning radius R of the rear automated guided vehicle 12 based on Equations 6 to 8. More precisely, the rotation speeds n1 and n2 of the wheels 18a and 18b are controlled so that the speed Vr, turning angle θr, and turning radius R all become set values. In the second traveling state, the two automated guided vehicles 11, 12 are ultimately lined up in a direction perpendicular to the direction along line L (see FIG. 3), and therefore the turning angles θf, θr of each automated guided vehicle 11, 12 ultimately become zero (equal). Furthermore, in order to move the rear automated guided vehicle 12 to a position where it is ultimately lined up alongside the front automated guided vehicle 11, the speed Vr of the rear automated guided vehicle 12 is always maintained at a value greater than the speed Vf (=V0) of the front automated guided vehicle 11 (see FIG. 6). In this way, while the front automated guided vehicle 11 travels on line L at a constant speed V0, the alignment direction of the two automated guided vehicles 11, 12 is changed by a predetermined angle (here, 90°).

[0042] As described above, in the automated guided vehicle 10 according to this embodiment, two automated guided vehicles 11, 12 are connected to each other by the connector 13, and each automated guided vehicle 11, 12 is connected to the connector 13 so as to be rotatable about a predetermined vertical axis. The travel of each automated guided vehicle 11, 12 can be controlled so that the front automated guided vehicle 11 travels on a predetermined line L, while the rear automated guided vehicle 12, which is connected to the front automated guided vehicle 11 via the connector 13, moves toward a position off the predetermined line L. Therefore, even without providing a curve section Lc (see FIG. 7 ) on the line L to change the orientation of a transported object, the autonomously traveling rear automated guided vehicle 12 can be made to travel in a different manner from the front automated guided vehicle 11, so that the front automated guided vehicle 11 and the rear automated guided vehicle 12 can be aligned in a desired orientation. This makes it possible to change the orientation of a transported object while minimizing the space required for each automated guided vehicle 11, 12 to travel.

[0043] In addition, in this embodiment, when changing the alignment direction of each automatic guided vehicle 11, 12 as described above, the second control unit 15b is configured to be able to control the speed Vr and turning angle θr of the rear automatic guided vehicle 12 based on the turning angle θf of the front automatic guided vehicle 11, and when the target position of the rear automatic guided vehicle 12 is located to the left or right of the direction of travel of the front automatic guided vehicle 11, the rear automatic guided vehicle 12 is caused to turn toward the left or right, and then takes a trajectory that switches the turning direction midway, and the speed Vr and turning angle θr of the rear automatic guided vehicle 12 are controlled by applying an equation for the turning angle θf that is different from one another in each turning state.

[0044] As described above, by taking a trajectory that switches the turning direction midway, the front automated guided vehicle 11 travels on the line L at a constant speed V0, while the rear automated guided vehicle 12 can be moved a short distance to a position where the alignment direction with the front automated guided vehicle 11 is changed. In this case, by applying different equations for the turning angle (Equations 2 to 4, Equations 6 to 8) before and after switching the turning direction, the speed Vr and turning angle θr suitable for each turning state can be calculated with high accuracy. Therefore, according to this control mode, it is possible to accurately move the rear automated guided vehicle 11 toward the target position.

[0045] Furthermore, in this embodiment, when controlling the turning speed and velocity as described above, second control unit 15b sets the turning radius R of rear-side automated guided vehicle 12 based on the turning angle θf of front-side automated guided vehicle 11, and is able to control the rotation speeds n1, n2 of each of wheels 18a, 18b based on the set turning radius R. When each of automated guided vehicles 11, 12 is able to turn based on the difference in the rotation speeds n1, n2 of the pair of independently driven wheels 18a, 18b as described above, the turning radius R of rear-side automated guided vehicle 12 is set based on the turning angle θf of front-side automated guided vehicle 11, and the difference in the rotation speeds n1, n2 of the pair of wheels 18a, 18b is controlled based on the set turning radius R, making it possible to easily set the turning angle θr of rear-side automated guided vehicle 12. Therefore, it is possible to accurately and directly control the turning of the rear automated guided vehicle 12, without having to detect the turning angle θr using the second angle detection unit 14b and perform feedback control of the turning angle θr based on the value of the detected turning angle θr. Also, in this case, the speed Vr can be directly set by the magnitude of the rotation speeds n1 and n2 of the wheels 18a and 18b. As described above, according to this control mode, it is possible to more accurately move the rear automated guided vehicle 12 toward the target position.

[0046] Although one embodiment of the present invention has been described above, the automatic transport device according to the present invention can also have configurations other than those described above within the scope of the gist of the invention.

[0047] For example, in the above embodiment, the speed Vr, turning angle θr, and turning radius R of the rear automated guided vehicle 12 are controlled by switching the control mode based on Formulas 1 to 8 depending on the running state (turning state) of the rear automated guided vehicle 12, but Formulas 1 to 8 are merely suitable examples. For example, the speed Vr, turning angle θr, and turning radius R may be controlled based on an appropriate formula for the turning angle θf, taking into consideration conditions other than those exemplified.

[0048] Of course, it is not necessary to control all of the above parameters (Vr, θr, R), and in some cases, the speed Vr and the turning angle θr, or the speed Vr and the turning radius R, may be controlled.

[0049] Furthermore, in the above embodiment, the case where communication units 17a, 17b are provided in each of the automated guided vehicles 11, 12 and the first communication unit 17a and the second communication unit 17b are capable of bidirectional communication is illustrated, but of course other configurations are also possible. For example, although not shown, a central control unit may be provided at a location separate from each of the automated guided vehicles 11, 12, and bidirectional communication may be performed between this central control unit and the communication units 17a, 17b of each of the automated guided vehicles 11, 12, so that the turning angle θf detected by the first angle detection unit 14a can be transmitted to the control unit (second control unit 15b) of the automated guided vehicle 12 located behind via the central control unit.

[0050] Furthermore, in the above explanation, an example has been given in which the connecting body 13 is integrally provided with the loading section 20 capable of loading an object (not shown), the first connecting section 21 located on the front side of the loading section 20 for connecting to one automated guided vehicle 11, and the second connecting section 22 located on the rear side of the loading section 20 for connecting to the other automated guided vehicle 12, but of course the connecting body 13 can have other configurations as well. For example, although not shown, when the object to be transported is a huge, heavy object such as an automobile body, the present invention can be applied even in a case in which the connecting body is configured so that the object to be transported straddles the front and rear connecting body elements, in other words, so that the object to be transported forms part of the connecting body.

[0051] In the above explanation, the present invention is applied to an automatic guided vehicle 10 in which two automatic guided vehicles 11 and 12 are connected to each other via a connector 13, but the present invention is not limited to this. For example, although not shown in the drawings, the present invention can also be applied to an automatic guided vehicle in which three or more automatic guided vehicles are connected to each other via a connector that is a rigid body. [Explanation of symbols]

[0052] 10 Automatic transport device 11,12 Automated guided vehicles 13 Concatenation 14a, 14b Angle detection unit 15a, 15b Control section 16a, 16b Speed ​​detection section 17a,17b Communication Department 18a,18b wheels 19a, 19b Drive source 20 Mounting section 21,22 Connecting part 21a,22a connection hole 23,24 Connecting shaft 111,112 Automated guided vehicles 113 Concatenation L Line Lc curve section O Turning center PC width center Pf,Pr connection point Pw1,Pw2 Center in width direction R Turning radius V0,Vf,Vr Speed θf,θr turning angle

Claims

1. A plurality of automated guided vehicles that can travel autonomously on a predetermined line, a connecting member that connects the plurality of automated guided vehicles to each other; a control unit capable of controlling the traveling of each of the automatic guided vehicles, and an automatic guided vehicle capable of transporting an object by cooperation of the plurality of automatic guided vehicles, Each of the automated guided vehicles is connected to the connecting body so as to be rotatable about a predetermined vertical axis; and The control unit is configured to control the running of each of the automatic guided vehicles so that the frontmost automatic guided vehicle among the plurality of automatic guided vehicles runs on the specified line, while the rearward automatic guided vehicle connected to the front automatic guided vehicle via the connecting body moves toward a position off the specified line.

2. When the rear automated guided vehicle is moved so that the alignment direction of the front automated guided vehicle and the rear automated guided vehicle is changed from an orientation along the line to an orientation intersecting the line, 2. The automatic transport device according to claim 1, wherein the control unit is configured to be able to control the speed of the rear automatic transport vehicle and the turning angle of the rear automatic transport vehicle relative to the connecting portion based on the turning angle of the front automatic transport vehicle relative to the connecting portion.

3. 3. The automatic transport device according to claim 2, wherein the control unit is configured to control the speed and the turning speed of the rear automatic transport vehicle by applying different equations for the turning angle in a first turning state in which the rear automatic transport vehicle turns toward one of the left and right sides and a second turning state in which the rear automatic transport vehicle turns toward the other of the left and right sides when the target position of the rear automatic transport vehicle is located on one of the left and right sides with respect to the direction of travel of the front automatic transport vehicle.

4. Each of the automated guided vehicles has a pair of wheels and a drive unit capable of independently driving each of the wheels, 3. The automatic guided vehicle according to claim 2, wherein the control unit is configured to set a turning radius of the rear automatic guided vehicle based on a turning angle of the front automatic guided vehicle, and to control the rotation speed of each wheel based on the set turning radius.

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