TRANSPORTATION DEVICE AND TRANSPORTATION METHOD

Abstract

To provide a transport device capable of approaching a position correctly connectable with respect to an object to be transported even in a narrow passage, and to provide a transport method.SOLUTION: A transport device includes: a body having a driving wheel; a pair of forks extending in a predetermined position from the body, and for lifting an object to be transported; driven wheels provided at tips of the pair of forks respectively; a lifting device for moving up / down the pair of forks; a plurality of sensors provided at the body part, and capable of detecting the position of the object to be transported; and an arithmetic device for generating locus data of a circular arc approach for moving to a position in which the pair of forks can be inserted, based on the detection result of the object to be transported by the sensor. The arithmetic device determines an end point of the locus data, a starting point of the circular arc locus data movable to the end point, and a posture of the body on the starting point of the locus data.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a transport device and a transport method. [Background technology]

[0002] In factories and logistics warehouses, it is common to transport objects using pallets and carts. When automating the above-mentioned transport methods using an AGV (Automatic Guided Vehicle), which is an example of a transport device, it is important for safety that the location of the object to be transported is accurately recognized and connected reliably. In addition, there are many cases where pallets and carts are mixed in factories and logistics warehouses. There are also various types of carts, such as basket carts and six-wheel carts. When automating the transport process in such factories and logistics warehouses using AGVs, a forklift type AGV that transports pallets, a hand pallet type AGV, and a towing type AGV that tows the carts are required. Summary of the Invention [Problem to be solved by the invention]

[0003] However, conventionally, when recognizing the position of an object to be transported, only one sensor facing the direction of the connection part (for example, a fork) with the object to be transported is used. In that case, if the connection part of the AGV is not facing the object to be transported, the position of the object cannot be recognized accurately. Even if a sensor with a detection area of ​​180 degrees or more is used and detection is possible in the lateral direction, some ingenuity is required to position the sensor so that it can detect 180 degrees or more without blind spots. In actual factories and logistics warehouses, it can be difficult to ensure a wide aisle width for the AGV to travel through, and it can be considered that the aisle width cannot be secured so that the AGV can move to a position where it can be reliably inserted after facing the connection part toward the object to be transported.

[0004] The present invention has been made in consideration of the above, and aims to provide a transporting device and a transporting method that enable approaching a position where the object to be transported can be correctly connected even in a narrow passage. [Means for solving the problem]

[0005] In order to solve the above problems and achieve the object, the present invention provides a lifting device that includes a main body having a driving wheel, a pair of forks extending in a predetermined direction from the main body for lifting an object to be transported, a driven wheel provided at the tip of each of the pair of forks, a lifting device that raises and lowers the pair of forks, and the main body. Left and right directions and a calculation device that generates trajectory data of an arc approach for moving the pair of forks to a position where the pair of forks can be inserted based on the detection result of the transported object by the sensors, and the calculation device determines an end point of the trajectory data, a start point of the trajectory data of the arc that can be moved to the end point, and a posture of the main body on the start point of the trajectory data. and detecting the position of the transported object by the sensor in a lateral orientation with respect to the transported object, and then retreating to the starting point of the trajectory data. do. Effect of the Invention

[0006] According to the present invention, it is possible to approach a position where a correct connection can be made to an object to be transported even in a narrow passage. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of a conveying device according to the present embodiment. [Figure 2A] FIG. 2A is a side view of the conveying device according to this embodiment. [Figure 2B] FIG. 2B is a diagram for explaining an example of a circular arc approach to an object to be transported in the transport device according to the present embodiment. [Figure 2C] FIG. 2C is a diagram for explaining an example of a circular arc approach to an object to be transported in the transport device according to the present embodiment. [Figure 2D] FIG. 2D is a diagram for explaining an example of a circular arc approach to the transport object in the transport device according to the present embodiment. [Figure 2E]FIG. 2E is a diagram for explaining an example of a circular arc approach to an object to be transported in the transport device according to the present embodiment. [Figure 2F] FIG. 2F is a diagram for explaining an example of a circular arc approach to an object to be transported in the transport device according to the present embodiment. [Figure 2G] FIG. 2G is a diagram for explaining an example of a circular arc approach to an object to be transported in the transport device according to the present embodiment. [Figure 2H] FIG. 2H is a diagram for explaining an example of a circular arc approach to an object to be transported in the transport device according to the present embodiment. [Figure 2I] FIG. 2I is a diagram for explaining an example of a circular arc approach to an object to be transported in the transport device according to the present embodiment. [Diagram 3] FIG. 3 is a perspective view showing an example of a shape of a pallet, which is an example of an object to be transported by the transport device according to the present embodiment. [Figure 4] FIG. 4 is a perspective view of a car truck as an example of a truck which is an example of an object to be transported by the transport device according to the present embodiment. [Diagram 5] FIG. 5 is a plan view for explaining a process in which the transport device according to the present embodiment recognizes the position of a pallet, which is an example of an object to be transported. [Figure 6] FIG. 6 is a plan view for explaining a process in which the transport device according to the present embodiment recognizes the position of a cart, which is an example of an object to be transported. [Figure 7A] FIG. 7A is a diagram for explaining an example of a trajectory when the transport device according to this embodiment approaches a position where the fork can be inserted into the transport object after recognizing the position of the transport object. [Figure 7B] FIG. 7B is a diagram for explaining an example of a trajectory when the transport device according to this embodiment approaches a position where the fork can be inserted into the transport object after recognizing the position of the transport object. [Figure 7C]FIG. 7C is a diagram for explaining an example of a trajectory when the transport device according to this embodiment approaches a position where the fork can be inserted into the transport object after recognizing the position of the transport object. [Figure 7D] FIG. 7D is a diagram for explaining an example of a trajectory when the transport device according to this embodiment approaches a position where the fork can be inserted into the transport object after recognizing the position of the transport object. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of a conveying device and a conveying method will be described in detail with reference to the accompanying drawings. In order to facilitate understanding of the description, the same reference numerals are used as much as possible for the same components in each drawing, and duplicated description will be omitted.

[0009] In the following description, the x, y, and z directions are perpendicular to each other. The x and y directions are typically horizontal, and the z direction is typically vertical. The x direction is the longitudinal direction of the pair of forks 6. The y direction is the arrangement direction of the pair of forks 6, and is the opening and closing direction of the pair of forks 6. In the following description, for convenience of explanation, the negative x direction side may be expressed as the front side, the positive x direction side as the rear side, the positive y direction side as the right side, the negative y direction side as the left side, the positive z direction side as the upper side, and the negative z direction side as the lower side.

[0010] The transport device 1 according to this embodiment can hold a pallet 31 (see FIG. 4) and a cart 41 (see FIG. 5, etc.) such as a cage cart, a six-wheel cart, or a dolly, and can transport the pallet 31 or the cart 41 as a transported object (object to be transported) to a desired position by autonomously moving while holding the pallet 31 or the cart 41. Note that the objects to be transported that the transport device 1 targets include objects having wheels other than the cart 41.

[0011] An example of the configuration of the transport device 1 according to the present embodiment will be described with reference to Figs. 1 and 2A. Fig. 1 is a perspective view of the transport device according to the present embodiment. Fig. 2A is a side view of the transport device according to the present embodiment. As shown in Fig. 1, the transport device 1 includes a main body 2, a driving wheel 3, a driving motor 4, a pair of driven wheels 5, a pair of forks 6, a lifting device 7, a lifting motor 8, an opening / closing device 9, an opening / closing motor 10, and a distance measuring sensor 11. The transport device 1 also includes a calculation device 12 that generates trajectory data of an arc approach that moves the pair of forks 6 to a position where they can be inserted, based on the recognition (detection) result of the transport object by the distance measuring sensor 11.

[0012] For example, a pair of drive wheels 3 are disposed in the center of the main body 2 in the y direction. The driving wheels 3 are variable in their traveling direction. A drive motor 4 drives the drive wheels 3. For example, as shown in FIG. 1, the drive motor 4 is individually installed on each of the pair of drive wheels 3. Note that there may be only one drive wheel 3 and one drive motor 4.

[0013] The pair of forks 6 are long members extending from the main body 2 in the x-direction (rearward), which is an example of a predetermined direction. The pair of forks 6 are arranged in parallel with each other at a predetermined interval. The pair of forks 6 are provided behind the drive wheels 3. The pair of forks 6 are for lifting a pallet 31 as an object to be transported.

[0014] The pair of driven wheels 5 are provided at the respective tips of the pair of forks 6. That is, the pair of driven wheels 5 are also provided behind the driving wheels 3. The driven wheels 5 have a rotation axis along the y-axis direction.

[0015] The lifting device 7 lifts and lowers the pair of forks 6 in the z direction. The lifting motor 8 drives the lifting device 7. The lifting device 7 may have a mechanism in which a ball screw is rotated by the lifting motor 8 to lift and lower the lifting device 7 fixed by fastening to a nut of the ball screw, for example, but the form and mechanism of the lifting device 7 are not limited thereto.

[0016] The distance measuring sensor 11 is an example of a sensor that is provided on the main body 2 and can detect the position of the transported object, such as a depth camera, a range sensor, or a 3D-LiDAR. The distance measuring sensor 11 may be installed on the fork 6 and movable in the y and z directions together with the fork 6. A plurality of distance measuring sensors 11 may be installed. For example, at least one may be installed on the right side of the main body 2, at least one on the left side of the main body 2, or at least one may be installed in the center of the main body 2 in the y direction. The distance measuring sensor 11 may be located in any of the x, y, and z directions as long as the detection position of the transported object is within the recognition range. The transport device 1 recognizes the length of the transported object in the y direction (width direction) using the distance measuring sensor 11, and changes the interval between the pair of forks 6 by the opening and closing device 9 according to the length.

[0017] The arithmetic device 12 is an example of a arithmetic device that generates trajectory data of an arc approach that moves to a position where the pair of forks 6 can be inserted based on the recognition (detection) result of the transport object by the distance measuring sensor 11. When generating the trajectory data of the arc approach, the arithmetic device 12 determines the end point of the trajectory data of the arc approach where the center of the pair of forks 6 coincides with the center of the transport object, and determines the start point of the trajectory data of the arc approach that can reach the end point. The arithmetic device 12 also determines the attitude of the transport device 1 on the start point of the trajectory data. By providing a plurality of distance measuring sensors 11 that recognize the position of the transport object, the detection area of ​​the distance measuring sensor 11 is expanded mainly in the lateral direction, and the position of the transport object can be recognized even when the transport object is placed laterally of the transport device 1. Then, since the arc approach where the center of the pair of forks 6 coincides with the center of the transport object is possible, it is possible to approach the transport object to a position where it can be correctly connected even in a narrow passage.

[0018] If the distance measuring sensor 11 that recognizes the position of the transported object cannot recognize the lateral direction of the transport device 1, the transport device 1 must make an arc-like approach to the transported object, then align the position while moving in the direction in which the pair of forks 6 will be inserted into the transported object, and then insert the forks 6 into the transported object. If the passage is narrow, the distance that the transport device 1 moves in the direction in which the forks 6 will be inserted into the transported object after the arc-like approach becomes short, making it difficult to align the forks 6 with the transported object.

[0019] Therefore, the transport device 1 according to the present embodiment is provided with a plurality of distance measuring sensors 11 for recognizing the position of the transport object, thereby expanding the detection area of ​​the distance measuring sensors 11 mainly in the lateral direction, and making it possible to recognize the position of the transport object before performing the arc approach. If the lateral direction can be recognized, the position of the transport object can be recognized before the arc approach. That is, by identifying a position where the pair of forks 6 can be inserted into the transport object and calculating a position where the arc approach can be made toward that position, it becomes unnecessary to perform an action of adjusting the position while moving in the direction in which the pair of forks 6 are inserted into the transport object after the arc approach. Therefore, as long as there is an aisle width that allows the arc approach, it becomes possible to correctly insert the pair of forks 6 into the transport object.

[0020] 2B to 2I are diagrams for explaining an example of an arc approach to an object to be transported by the transport device according to the present embodiment. As shown in FIG. 2B, in a narrow passage or the like, after the transport device 1 approaches the object to be transported in an arc, the distance between the transport device 1 and the object to be transported is short, making it difficult to insert the pair of forks 6 while aligning them with the object to be transported. In this case, as shown in FIG. 2C and FIG. 2D, it is necessary to approach the object to be transported so that the pair of forks 6 can be inserted while approaching the object to be transported.

[0021] However, when the conveying device 1 makes an arc approach as shown in Fig. 2E, the distance between the object to be conveyed and the pair of forks 6 is short, and it may be difficult for the conveying device 1 to move toward the object to a positional relationship that allows the pair of forks 6 to be inserted. In this case, as shown in Fig. 2F and Fig. 2G, the conveying device 1 must first move away from the object to be conveyed, and then move toward the object to a positional relationship that allows the pair of forks 6 to be inserted, requiring an extra passage width for the distance.

[0022] Therefore, in this embodiment, as described above, the conveying device 1 identifies a position where the pair of forks 6 can be inserted into the transport object, and calculates a position where a circular approach can be made toward that position, eliminating the need to adjust the position while moving in the direction in which the pair of forks 6 will be inserted into the transport object after the circular approach. Therefore, as long as there is a passage width that allows for a circular approach, it becomes possible to correctly insert the pair of forks 6 into the transport object.

[0023] Furthermore, when it is recognized that the object to be transported is placed at an angle to the transport device 1 as shown in Fig. 2H, the transport device 1 determines the posture at the starting point position so that an arc approach is possible so that the center of the pair of forks 6 coincides with the center of the object to be transported as shown in Fig. 2I. In this way, by adjusting the posture of the starting point, the transport device 1 can always approach the object by tracing a similar arc radius, regardless of how the object is placed.

[0024] The transport device 1 also includes an opening / closing device 9 and an opening / closing motor 10. The opening / closing device 9 varies the distance between the pair of forks 6 (and the driven wheels 5 provided on the forks 6). The opening / closing motor 10 drives the opening / closing device 9. The opening / closing device 9 shown in FIG. 1 may have a mechanism in which a structural member provided with a rack gear is attached to the forks 6 holding the pair of driven wheels 5 or to the lifting device 7 for raising and lowering the forks 6 holding the pair of driven wheels 5, and the gear meshed with the rack gear is rotated by the opening / closing motor 10 to achieve opening and closing, but the form is not limited as long as the mechanism can vary the distance between the pair of driven wheels 5 or the distance between the forks 6 holding the pair of driven wheels 5.

[0025] In this embodiment, when the transport device 1 travels with the main body 2 in front, that is, moving in the negative x direction, it is considered to move forward, and when the transport device 1 travels with the pair of forks 6 in front, that is, moving in the positive x direction, it is considered to move backward. In other words, the main body 2 side of the transport device 1 is the front, and the pair of forks 6 side is the rear.

[0026] In addition, the transport device 1 is preferably provided with an autonomous travel function that allows the transport device 1 to travel autonomously without operation input from an operator, such as an AGV (Automatic Guided Vehicle). Furthermore, these autonomous travel functions and an automatic coupling control function with the transport object enable the transport device 1 to automatically transport the pallet 31 or the dolly 41 without the help of an operator, thereby improving the convenience and versatility of the transport device 1. The automatic coupling control function and the autonomous travel function are implemented by a control device such as a computer installed inside the main body 2 of the transport device 1. The control device may be installed outside the transport device 1 and connected to the transport device 1 so as to be able to communicate with the transport device 1 via wire or wirelessly.

[0027] With reference to FIG. 3, an example of a transport object to be transported by the transport device according to this embodiment will be described. FIG. 3 is a perspective view showing an example of the shape of a pallet, which is an example of a transport object to be transported by the transport device according to this embodiment. The pallet 31 is composed of a deck board 32 on which cargo is placed, an under-deck 33 that is in contact with the floor, and girders 34 that connect the deck board 32 and the under-deck 33. The side of the pallet 31 has gaps between the multiple girders 34 that function as insertion openings 35 into which the forks 6 can be inserted. Depending on the type of pallet 31, there may be no under-deck 33, or the deck board 32 or the under-deck 33 may be hollowed out. The material of the pallet 31 may be wood, plastic, cardboard, or the like.

[0028] FIG. 4 is a perspective view of a cage dolly as an example of a dolly, which is an example of an object to be transported by the transport device according to this embodiment. The dolly 41 includes a base plate 42 parallel to the floor, a base plate frame 43 that holds the base plate 42, and wheels 44 provided on the base plate frame 43. Depending on the type (for example, in the case of a cage dolly), the dolly 41 may have a fence 45 provided on the base plate 42. The dolly 41, which is the object to be transported in this embodiment, is a wheeled dolly that is generally used in logistics warehouses and factories. It does not matter how many wheels there are, or whether they are swivel wheels or fixed wheels. Examples of the dolly 41 include a cage dolly, a six-wheel cart, and a dolly. For example, a cage dolly generally has four wheels, but two of the four wheels may be swivel wheels and the remaining two wheels may be fixed wheels, or all four wheels may be swivel wheels. Also, a six-wheeled cart generally has six wheels, with the two central wheels being fixed wheels and the remaining four being swivel wheels. As described above, the wheel configuration differs depending on the type of cart, but the transport device 1 of this embodiment is capable of transporting regardless of the wheel configuration of the cart 41. Also, there are some carts, such as dollies, in which the base plate 42 and the base plate frame 43 are the same member.

[0029] 5 is a plan view for explaining a process in which the transport device according to this embodiment recognizes the position of a pallet, which is an example of a transport target. The transport device 1 detects three beams 34 provided on the front side of the pallet 31 using the distance measurement sensor 11, and calculates the center position of the central beam 34 of the three beams, thereby recognizing the center of the pallet 31 and identifying the position of the pallet 31. The transport device 1 also detects three beams 34 provided on the front side of the pallet 31, and calculates the width of the central beam 34 of the three beams, thereby identifying the inner width of the pallet 31, and also identifies the outer width of the pallet 31 from the left and right beams 34.

[0030] 6 is a plan view for explaining a process in which the transport device according to the present embodiment recognizes the position of a dolly, which is an example of a transport object. The transport device 1 detects two wheels 44 provided on the front side of the dolly 41 by using the distance measurement sensor 11, and calculates the position of the midpoint of the line segment connecting the center points of the two wheels 44, thereby recognizing the center of the dolly 41 and identifying the position of the dolly 41. The transport device 1 also detects two wheels 44 provided on the front side of the dolly 41, and calculates the length of the inner width of the two wheels 44 to identify the width of the dolly 41.

[0031] 7A to 7D are diagrams for explaining an example of a trajectory when the transport device according to this embodiment approaches a position where the forks can be inserted into the transport object after recognizing the position of the transport object. In this embodiment, the transport device 1 approaches a position where the pair of forks 6 can be inserted into the transport object by retreating in an arc. Point A is the center of the pair of driven wheels 5 when the transport device 1 recognizes the position of the transport object (e.g., pallet 31). After the transport device 1 recognizes the position of the transport object, the transport device 1 calculates trajectory data of an arc approach such that the center in the width direction of the pair of forks 6 (point D shown in FIG. 7D) coincides with the center in the front width direction of the transport object, as shown in FIG. 7B.

[0032] Thereafter, as shown in FIG. 7A, the transport device 1 arrives at the start point of the arc approach by moving the center of the pair of driven wheels 5 from point A to point B. At this time, the transport device 1 may change the width of the pair of forks 6 to a width suitable for inserting the transport object by the opening and closing device 9. The timing for changing the width of the pair of forks 6 is not limited as long as it is between the time when the transport device 1 recognizes the position and width of the transport object and the time when it connects to the transport object. After the center of the pair of driven wheels 5 moves to the start point of the arc approach, the transport device 1 moves backward so that the pair of forks 6 face the direction of the transport object so that the center of the width direction of the pair of forks 6 draws the calculated trajectory of the arc approach as shown in FIG. 7B to 7D, and the center of the pair of driven wheels 5 is positioned at point D via point C.

[0033] In this way, according to the conveying device 1 of this embodiment, by providing multiple distance measuring sensors 11 that recognize the position of the object to be transported, the detection area of ​​the distance measuring sensor 11 is expanded mainly in the horizontal direction, and the position of the object to be transported can be recognized even when the object to be transported is placed horizontally of the conveying device 1, making it possible to approach a position where the object to be transported can be correctly connected even in a narrow passage. [Explanation of symbols]

[0034] 1. Transport device 2 Main unit 3 Driving wheels 4 Drive motor 5 Driven wheels 6. Fork 7 Lifting device 8 Lifting motor 9. Switchgear 10 Opening and closing motor 11 Distance sensor 12 Arithmetic unit 31 Palette 32 Deck Board 33 Below Deck 34 digits 35 Insertion port 41 Trolley 42 Base plate 43 Base plate frame 44 wheels

Prior art documents

Patent documents

[0035]

Patent Document 1

Claims

1. A body having a drive wheel; A pair of forks extending in a predetermined direction from the main body for lifting an object to be transported; A driven wheel provided at each end of the pair of forks; A lifting device that lifts and lowers the pair of forks; A plurality of sensors are provided on the left and right sides of the main body and are capable of detecting the position of the transported object; and a calculation device that generates trajectory data of an arc approach for moving the pair of forks to a position where the pair of forks can be inserted based on a result of detection of the transported object by the sensor, the computing device determines an end point of the trajectory data, a start point of the trajectory data that is movable to the end point, and an attitude of the main body on the start point of the trajectory data; The transport device detects the position of the transported object by the sensor in a horizontal orientation with respect to the transported object, and then retreats to the starting point of the trajectory data.

2. A transport method carried out by a transport device including a main body having drive wheels, a pair of forks extending in a predetermined direction from the main body for lifting an object to be transported, driven wheels provided at the tip of each of the pair of forks, a lifting device for raising and lowering the pair of forks, and a plurality of sensors provided on the left and right sides of the main body and capable of detecting the position of the object to be transported, generating trajectory data of an arc approach for moving the pair of forks to a position where the pair of forks can be inserted based on a result of detection of the transported object by the sensor; determining an end point of the trajectory data, a start point of the trajectory data that is movable to the end point, and a posture of the body on the start point of the trajectory data; a step of detecting a position of the transported object by the sensor in a lateral posture with respect to the transported object, and then retreating to a start point of the trajectory data; A transportation method including:

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