Conveyance system, conveyance vehicle, and station entry method

Abstract

A conveyance system comprises: an autonomous mobile robot (AMR) (2) which autonomously controls travel and conveys a conveyance target object; and a station (1) which includes an entrance / exit port (120) through which the AMR (2) enters and exits. The AMR (2) includes: drive wheels (25a, 25b) which are provided at the center of a vehicle body in the front-rear direction thereof; driven wheels (30a, 30b, 32a, 32b) which are provided forward of the vehicle body and backward thereof; and a bogie mechanism in which the drive wheels (25a, 25b) and the driven wheels (30a, 30b) that are provided forward of the vehicle body are connected by connecting members (34a, 34b) that are rotatably provided on the vehicle body. The AMR (2) enters the entrance / exit port (120) by forward movement when entering the entrance / exit port (120) to convey the conveyance target article into the station (1) and enters the entrance / exit port (120) by backward movement when entering the entrance / exit port (120) to convey the conveyance target object out of the station (1).

Description

Transport system, transport vehicle, and station entry method

[0001] The present disclosure relates to a transport system, a transport vehicle, and a station entry method.

[0002] In factories that process materials such as sheet metal, continuous processing is often performed using different types of processing machines. For example, material cut by a laser cutting machine is bent into a desired shape by a press brake. In the factory, a station is provided for each processing machine to place a pallet carrying the material, and material is automatically transported by a transport vehicle traveling between the stations. The transport vehicle is an autonomous mobile robot known as an AMR (Autonomous Mobile Robot), and is equipped with the ability to estimate its own position using sensors and travel autonomously.

[0003] Such AMRs are equipped with a bogie mechanism to ensure stable driving force even when traveling through factories where foreign objects are often found. For example, Patent Document 1 discloses a traveling device that allows stable traveling and a low floor with a simple configuration.

[0004] Japanese Patent Application Laid-Open No. 2021-126913

[0005] However, in the conventional traveling device described above, since the bogie mechanism is provided only on the front wheel side, it is not possible to obtain a stable driving force when reversing with a load loaded. Furthermore, if a bogie mechanism is provided on the rear wheel side to obtain a stable driving force even when reversing, there is a problem that the number of parts increases and the cost increases.

[0006] A conveying system according to one aspect of the present disclosure comprises a conveying vehicle that autonomously controls its driving to convey an item to be conveyed, and a station into which the item is conveyed by the conveying vehicle and which has an entrance / exit through which the conveying vehicle enters and exits, wherein the conveying vehicle has a drive wheel provided in the center of the fore-and-aft direction of the body, driven wheels provided at the front and rear of the body, respectively, and a bogie mechanism connecting the drive wheel and the driven wheel at the front of the body with a connecting member that is rotatably provided on the body, and when entering the entrance / exit to convey the item to the station, the conveying vehicle moves forward to enter the entrance / exit, and when entering the entrance / exit to convey the item out of the station, the conveying vehicle moves backward to enter the entrance / exit.

[0007] According to one aspect of the conveyance system of the present disclosure, when an item is to be transported into a station, the conveyance vehicle moves forward to enter the entrance / exit opening, and when an item is to be transported out of the station, the conveyance vehicle moves backward to enter the entrance / exit opening. As a result, the conveyance vehicle always moves forward when an item is loaded, so even if a bogie mechanism is provided only on the front side, a stable driving force can always be obtained when an item is loaded. Furthermore, since there is no need to provide a bogie mechanism on the rear side, an increase in costs due to an increase in the number of parts can be prevented.

[0008] According to one aspect of the present disclosure, a stable driving force can be obtained at all times when an object to be transported is loaded, and an increase in costs due to an increase in the number of parts can be prevented.

[0009] FIG. 1 is an explanatory diagram showing the system configuration of a conveyance system according to this embodiment. FIG. 2 is a diagram explaining an environment in which the conveyance system is applied. FIG. 3 is a perspective view showing the external configuration of an AMR. FIG. 4A is a perspective view showing the internal structure of the AMR. FIG. 4B is a perspective view showing the internal structure of the AMR. FIG. 5 is a block diagram showing the configuration of the AMR. FIG. 6 is a perspective view showing the structure of a station. FIG. 7 is a flowchart showing the processing procedure for station entry processing by the AMR. FIG. 8 is a flowchart showing the processing procedure for station entry processing by the AMR, subsequent to FIG. 7. FIG. 9 is a diagram showing how the AMR travels until it reaches a scan position. FIG. 10A is a diagram showing how the AMR enters the station when a pallet is loaded. FIG. 10B is a diagram showing how the AMR leaves the station after placing a pallet at the station. FIG. 11A is a diagram showing how the AMR enters the station when no pallet is loaded. FIG. 11B is a diagram showing how the AMR leaves the station after loading a pallet at the station. Fig. 12 is a diagram showing how the AMR travels until it enters the parking space. Fig. 13 is a diagram showing how the AMR travels until it stops at the parking position. Fig. 14 is a diagram showing how the AMR according to the second embodiment approaches the station.

[0010] First Embodiment Hereinafter, a conveyance system, a conveyance vehicle, and a station entry method according to this embodiment will be described with reference to the drawings.

[0011] 1 is an explanatory diagram showing the system configuration of a conveyance system according to this embodiment. The conveyance system according to this embodiment includes a conveyance vehicle (hereinafter referred to as an AMR (Autonomous Mobile Robot)) 2 that autonomously controls its travel to convey an object, and a station 1 through which the AMR 2 carries in or carries out an object and which has an entrance / exit 120 through which the AMR 2 enters and exits. The AMR 2 includes drive wheels 25a, 25b provided in the center of the vehicle body 200 in the longitudinal direction, driven wheels 30a, 30b, 32a, 32b provided at the front and rear of the vehicle body 200, respectively, and a bogie mechanism that connects the drive wheels 25a, 25b to the driven wheels 30a, 30b at the front of the vehicle body 200 with connecting members 34a, 34b rotatably provided on the vehicle body 200. When AMR2 enters the entrance / exit 120 to transport the transported item into station 1, it advances to enter the entrance / exit 120, and when it enters the entrance / exit 120 to transport the transported item out of station 1, it retreats to enter the entrance / exit 120.

[0012] The side of the driven wheels 30a and 30b that constitute the bogie mechanism of the AMR 2 is the forward direction, which is shown in FIG. 1 as the traveling direction FW. Therefore, the direction opposite to the traveling direction FW in FIG. 1, the left side of the traveling direction FW, and the right side of the traveling direction FW are the rear, left, and right directions of the AMR 2, respectively. The direction of station 1 is determined by the direction seen from the AMR 2 when it is facing forward relative to the entrance / exit 120 of station 1. Specifically, the side closer to the AMR 2 (near side), the side farther from the AMR 2 (rear side), the left side of the AMR 2, and the right side of the AMR 2 are the front, rear, left, and right directions of station 1, respectively.

[0013] The conveying system according to this embodiment will be described in detail below. FIG. 2 is a diagram illustrating an environment in which the conveying system according to this embodiment is applied. The environment in which the conveying system according to this embodiment is applied is, for example, a factory. The factory is provided with a first processing machine 7, such as a laser cutting machine, that cuts materials, and a second processing machine 8, such as a press brake, that bends materials. In this factory, the first processing machine 7 cuts materials to produce parts for a specified product, and the second processing machine 8 bends the product parts to produce the specified product.

[0014] The conveying system is a system that automatically conveys materials. The material conveyance by the conveying system includes carrying in materials (materials before processing) to the first processing machine 7, carrying out materials (components for products) processed by the first processing machine 7 and carrying them into the second processing machine 8, and carrying out materials (products) processed by the second processing machine 8.

[0015] The conveying system is composed of two stations 1 and an AMR 2. The two stations 1 are provided corresponding to the first and second processing machines 7 and 8. The individual stations 1 have the same configuration. The AMR 2 transports pallets (an example of a transported object) 5 carrying materials to each station 1, thereby transporting materials to and from each of the processing machines 7 and 8.

[0016] 2, the factory is provided with two processing machines 7 and 8 and two stations 1, but this embodiment is not limited to this. Also, although one AMR 2 that transports a pallet 5 is shown as an example, this embodiment is not limited to this.

[0017] [AMR Configuration] First, the AMR 2 according to this embodiment will be described with reference to Figures 1 and 3 to 5. Figure 3 is a perspective view showing the external configuration of the AMR. Figures 4A and 4B are perspective views showing the internal structure of the AMR. Figure 5 is a block diagram showing the configuration of the AMR.

[0018] The AMR 2 is a transport vehicle that autonomously controls its travel based on the results of detection of surrounding objects and transports the transported object, the pallet 5. The AMR 2 is equipped with a battery (not shown) and travels using power supplied from the battery.

[0019] As shown in Figures 3, 4A, and 4B, the AMR 2 includes a vehicle body 200, a top plate 210, drive wheels 25a and 25b, front driven wheels 30a and 30b, rear driven wheels 32a and 32b, and connecting members 34a and 34b.

[0020] The top plate 210 forms the ceiling portion of the vehicle body 200, and can carry a pallet 5 (not shown). That is, the AMR 2 transports the pallet 5 by traveling with the pallet 5 loaded on the top plate 210.

[0021] The drive wheels 25a, 25b are provided in the center of the vehicle body 200 in the longitudinal direction, and rotate around horizontal rotation shafts provided at the rear ends of the connecting members 34a, 34b.

[0022] The driven wheels 30a, 30b are casters provided at the front of the vehicle body 200, and rotate around horizontal rotation axes to move the AMR 2 in the traveling direction. The driven wheels 30a, 30b also rotate around vertical rotation axes provided at the front ends of the connecting members 34a, 34b to change the traveling direction of the AMR 2.

[0023] The driven wheels 32a, 32b are casters provided at the rear of the vehicle body 200, which rotate around a horizontal axis to move the AMR2 in the direction of travel, and rotate around a vertical axis provided on the vehicle body 200 to change the direction of travel of the AMR2.

[0024] The connecting members 34a, 34b connect the drive wheels 25a, 25b to the driven wheels 30a, 30b at the front of the vehicle body 200, and are rotatably mounted on the vehicle body 200. Driven wheels 30a, 30b and drive wheels 25a, 25b are rotatably mounted on both ends of the connecting members 34a, 34b, respectively, and the connecting members 34a, 34b rotate up and down around horizontal rotation shafts 36a, 36b in the center. In other words, when the driven wheels 30a, 30b rise, the drive wheels 25a, 25b descend, and when the driven wheels 30a, 30b descend, the drive wheels 25a, 25b rise.

[0025] The AMR2 includes a bogie mechanism that connects the drive wheels 25a, 25b and the driven wheels 30a, 30b with connecting members 34a, 34b. The bogie mechanism is provided to prevent the drive wheels 25a, 25b from coming off the ground and to obtain a stable driving force. For example, if the front driven wheels 30a, 30b were to run over an object without the bogie mechanism, the vehicle body 200 would be supported between the front driven wheels 30a, 30b and the rear driven wheels 32a, 32b. Therefore, the drive wheels 25a, 25b in the center would be lifted off the ground and unable to obtain driving force.

[0026] However, with the bogie mechanism, when the AMR 2 moves forward and the driven wheels 30a, 30b run over an object and rise, the connecting members 34a, 34b rotate vertically around the pivot shafts 36a, 36b, causing the drive wheels 25a, 25b to descend. Therefore, the drive wheels 25a, 25b can always be in contact with the ground, so the AMR 2 can obtain stable driving force even in places such as sheet metal factories where scrap metal is lying around.

[0027] Furthermore, although the AMR2 is equipped with a bogie mechanism only on the front side, when it is carrying an object requiring driving force, as will be described later, the AMR2 is controlled to always move forward. Therefore, if the bogie mechanism is only on the front side, the AMR2 can always obtain a stable driving force. Furthermore, by providing a bogie mechanism only on the front side, the number of parts can be reduced compared to when a bogie mechanism is also provided on the rear side, which also helps prevent an increase in costs.

[0028] 5, the AMR 2 includes a control unit 21, a wireless communication unit 22, a pair of sensors 23a, 23b, a pair of drive motors 24a, 24b, a pair of drive wheels 25a, 25b, a lifter drive unit 26, a lifter 27, and a map storage unit 29. These elements constituting the AMR 2 are housed in a vehicle body 200 shown in FIG.

[0029] The control unit 21 is configured with a computer such as a microcomputer, and controls the operation of the AMR 2. The wireless communication unit 22 communicates with external devices such as the first and second processing machines 7 and 8, or a management device that manages production in the factory. The wireless communication unit 22 can be configured with a communication circuit and a wireless transceiver.

[0030] The pair of sensors 23a, 23b have the same configuration, so the configuration of one of the sensors, 23a, will be described. The sensor 23a detects surrounding objects by irradiating the surroundings with detection light and receiving reflected light. For example, the sensor 23a is a LiDAR (Light Detection and Ranging) sensor that acquires point cloud data indicating the distances to objects present around the AMR 2. Note that the sensors 23a, 23b may also be stereo cameras or TOF (Time Of Flight) sensors.

[0031] As shown in FIG. 1 , of the pair of sensors 23a, 23b, one sensor 23a is disposed at the left end in front of the vehicle body 200 of the AMR 2, and the other sensor 23b is disposed at the right end in rear of the vehicle body 200 of the AMR 2. One sensor 23a is mounted slightly to the left of the front face of the AMR 2. One sensor 23a has a detection range θb1 that is sufficient to detect objects present in front of and to the left of the AMR 2. The other sensor 23b is mounted slightly to the right of the front face of the rear of the AMR 2. The other sensor 23b has a detection range θb2 that is sufficient to detect objects present behind and to the right of the AMR 2. This arrangement of the pair of sensors 23a, 23b makes it possible to detect the entire area around the AMR 2 even with a small number of sensors.

[0032] 5, one drive motor 24a is a motor that rotates one drive wheel 25a, and the other drive motor 24b is a motor that rotates the other drive wheel 25b. Each drive motor 24a, 24b can be independently controlled by the control unit 21.

[0033] As shown in Fig. 1, a pair of drive wheels 25a, 25b are arranged on the vehicle body 200 with a space between them on the left and right. The orientation of each of the drive wheels 25a, 25b is fixed relative to the vehicle body 200. As shown in Fig. 3, when the AMR 2 moves forward, the pair of drive wheels 25a, 25b rotate in a rotational direction R1 and move in the direction of the arrow FW. If the drive wheels 25a, 25b rotate in the direction opposite to the rotational direction R1 shown in Fig. 3, the AMR 2 moves backward.

[0034] 5, the lifter driving unit 26 is a driving unit that drives the lifter 27, and is configured by an actuator such as a motor. The lifter 27 is a lifting mechanism that lifts and lowers an object to be transported, and raises and lowers the top plate 210. When the lifter 27 raises the top plate 210 of the AMR 2 with the pallet 5 placed on it, the pallet 5 is lifted upward.

[0035] The lifter 27 is equipped with a limit switch (not shown), and when the lifter 27 rises, the limit switch turns ON, allowing the control unit 21 to detect whether the lifter 27 is raised or not by the ON / OFF state of the limit switch. Furthermore, the lifter 27 is always raised when a pallet 5 is placed on the top plate 210, and is always lowered when no pallet 5 is placed on the top plate 210. Therefore, the control unit 21 determines that an object is loaded when the limit switch is ON and the lifter 27 is raised, and determines that an object is not loaded when the limit switch is OFF and the lifter 27 is lowered. Note that if the lifter 27 is equipped with a cylinder for raising and lowering the top plate 210, it may also be possible to determine whether an object is loaded or not by the ON / OFF state of the cylinder switch.

[0036] The map storage unit 29 stores map data of the environment in which the AMR 2 travels, i.e., the factory. This map data is composed of point cloud data obtained when the AMR 2 travels through the factory in advance. The map storage unit 29 is composed of, for example, a non-volatile memory.

[0037] In the AMR 2 configured as described above, the sensors 23 a and 23 b detect surrounding objects by emitting detection light to the area around the AMR 2 and receiving the reflected light. The detection of surrounding objects corresponds to the detection of point cloud data indicating the distances to objects around the AMR 2. The AMR 2 travels autonomously based on the detection results of the sensors 23 a and 23 b and transports the pallet 5.

[0038] During this autonomous driving, the control unit 21 estimates the position of the AMR 2 (its own position) by matching the map data read from the map storage unit 29 with the detection results of the sensors 23 a and 23 b. The control unit 21 then determines the path of the AMR 2 by controlling the drive motors 24 a and 24 b based on the estimated self-position, thereby allowing the AMR 2 to travel to a destination location within the factory. Furthermore, if the control unit 21 recognizes an object (obstacle) that does not exist in the map data from the detection results of the sensors 23 a and 23 b, it can avoid the object by controlling the drive motors 24 a and 24 b.

[0039] [Structure of Station] Next, the station 1 will be described with reference to Fig. 1 and Fig. 6. Fig. 6 is a perspective view showing the structure of the station. The station 1 is composed of four legs 100, 101, 102, and 103 and a support part 110.

[0040] As shown in Figure 6, the four legs 100, 101, 102, and 103 are arranged at the corners of a support part 110 having a substantially rectangular shape. The area surrounded by the four legs 100, 101, 102, and 103 corresponds to a parking space Ps for the AMR 2 to enter and stop. The AMR 2 enters the parking space Ps through an entrance / exit 120 and exits through the entrance / exit 120. In other words, the AMR 2 enters and exits the parking space Ps from one direction.

[0041] The support part 110 is supported by four legs 100, 101, 102, and 103, and is disposed above the parking space Ps where the AMR2 entering through the entrance / exit 120 stops. The support part 110 is a frame having a substantially rectangular shape, and is configured so that a pallet 5 can be placed thereon. The front side of the support part 110 is open so that the AMR2 can enter. The pallet 5 placed on the support part 110 is located above the entrance / exit 120.

[0042] 1, the pair of front legs 100, 102 are spaced apart on the left and right sides when viewed from the AMR 2 entering the parking space Ps. The left and right legs 100, 102 correspond to left and right structures that define an entrance / exit 120 to the parking space Ps.

[0043] As shown in Figure 6, a left lateral wall 130 that defines the left boundary of the parking space Ps is provided between the pair of legs 100, 101 on the left side. The left lateral wall (hereinafter referred to as the "left wall") 130 is a plate-like member that stands upright in the vertical direction and is provided along the front-to-rear direction, which is the direction in which the AMR 2 enters the parking space Ps. The left wall 130 is also formed flush along the front-to-rear direction.

[0044] A right lateral wall 132 that defines the right boundary of the parking space Ps is provided between the pair of legs 102, 103 on the right side. The function and structure of the right lateral wall (hereinafter referred to as the “right wall”) 132 are similar to those of the left wall 130.

[0045] As shown in FIG. 1 , station 1 includes a first approach reflector 140, a second approach reflector 141, and a stop reflector 145. Each reflector 140, 141, and 145 is used when AMR 2 enters and stops at station 1. Each reflector 140, 141, and 145 is a reflective member that reflects light (incident light) and can reflect detection light emitted from sensors 23 a and 23 b mounted on AMR 2. Each reflector 140, 141, and 145 is configured, for example, as a prism reflector. Each reflector 140, 141, and 145 can reflect detection light with a higher brightness than objects surrounding AMR 2. This allows AMR 2 to distinguish and recognize reflectors 140, 141, and 145 from other objects based on the brightness level of the reflected light.

[0046] The first approach reflector 140 is disposed on the leg 100 located on the front left, and the second approach reflector 141 is disposed on the leg 102 located on the front right. The first and second approach reflectors 140, 141 are reflectors for guiding the AMR2 as it travels toward the entrance / exit 120. The first and second approach reflectors 140, 141 are disposed on the front surfaces of the legs 100, 102 so as to face the AMR2 entering the parking space Ps. Specifically, the first and second approach reflectors 140, 141 are disposed so that the centers of their reflection ranges θa1, θa2 are aligned in the front-to-rear direction.

[0047] On the other hand, the stopping reflector 145 is disposed on the left wall 130 and is a reflector for stopping the AMR 2 at a specified stopping position within the stopping space Ps. When viewed from the AMR 2 entering the stopping space Ps, the stopping reflector 145 is disposed further back (rearward) of the stopping space Ps than the entry reflectors 140 and 141. In the example shown in FIG. 1 , the stopping reflector 145 is disposed at the farthest end of the stopping space Ps, for example, at the same position as the left rear leg 101. This stopping reflector 145 is disposed to face the right wall 132. Specifically, the stopping reflector 145 is disposed so that the center of its reflection range θa3 is aligned along the left-right direction, which is a direction perpendicular to the entry direction of the AMR 2.

[0048] The first and second approach reflectors 140, 141 have a convex shape that bulges forward so that they can be widely detected by the AMR2 before entering the parking space Ps. In contrast, the stopping reflector 145 has a flat shape. Therefore, the reflection ranges θa1, θa2 of the first and second approach reflectors 140, 141 are larger than the reflection range θa3 of the stopping reflector 145. Here, the "reflection range" refers to the range of incident angles over which the reflected light can maintain a certain intensity or more when the detection light is incident on the reflector.

[0049] Station 1 configured as described above can support pallets 5 transported by AMR 2 with support parts 110. When transporting an article into station 1, AMR 2 enters stopping space Ps with lifter 27 on which pallet 5 is loaded raised. Then, after entering stopping space Ps and stopping, AMR 2 controls lifter drive part 26 to lower lifter 27. This allows AMR 2 to place pallet 5 on support part 110 of station 1 and transport the article into station 1.

[0050] On the other hand, when carrying out an article from station 1, AMR 2 enters stopping space Ps with lifter 27 lowered and without pallet 5 loaded. Then, after entering stopping space Ps and stopping, AMR 2 controls lifter drive unit 26 to raise lifter 27. This allows AMR 2 to load pallet 5 placed on support unit 110 of station 1 onto top plate 210 and carry out the article from station 1. Thereafter, AMR 2 travels with pallet 5 lifted upward without lowering lifter 27.

[0051] [Station Entry Processing] Hereinafter, with reference to Figs. 7 to 13, a station entry method, which is a series of steps up to entering and stopping the AMR 2 in the stopping space Ps of station 1, will be described. Here, Figs. 7 and 8 are flowcharts showing the processing steps of the station entry processing by the AMR 2 according to this embodiment. Fig. 9 is a diagram showing the traveling of the AMR 2 until it reaches the scanning position. Figs. 10A and 10B are diagrams showing the entering and leaving of the AMR 2 to the station 1 when carrying in a pallet. Figs. 11A and 11B are diagrams showing the entering and leaving of the AMR 2 to the station 1 when carrying out a pallet. Fig. 12 is a diagram showing the traveling of the AMR 2 until it enters the stopping space Ps. Fig. 13 is a diagram showing the traveling of the AMR 2 until it stops at the stopping position.

[0052] 7, the control unit 21 receives a movement command to the station 1 via the wireless communication unit 22. The movement command is transmitted from the first processing machine 7 or the second processing machine 8 (see FIG. 2) in the factory, or from an external device such as a management device that manages production in the factory.

[0053] In step S11, the control unit 21 causes the AMR 2 to travel from its current position to the scan position Psc by self-position estimation, as shown in Fig. 9. Specifically, the control unit 21 estimates the current position of the AMR 2 by matching the map data with the detection results of the sensors 23a and 23b. The control unit 21 then controls the drive motors 24a and 24b based on the results of the self-position estimation, thereby allowing the AMR 2 to travel toward the scan position Psc.

[0054] The scan position Psc is defined in advance as the position and orientation at which the AMR 2 faces the entrance / exit 120 of the parking space Ps, and the control unit 21 holds information about the scan position Psc in advance. The AMR 2 continues traveling by estimating its own position under the control of the control unit 21, and thus the AMR 2 can reach the scan position Psc.

[0055] In step S12 of Fig. 7, the control unit 21 completes positioning and angle determination with respect to the scan position Psc. The movement of the AMR 2 based on self-position estimation contains some error. Therefore, as shown in Fig. 9, even when the control unit 21 has performed positioning and angle determination of the AMR 2 with respect to the scan position Psc, deviation of the AMR 2 with respect to the scan position Psc may occur.

[0056] 7, the control unit 21 determines whether the AMR 2 is entering the entrance / exit 120 to carry the transported article into station 1. If the AMR 2 is entering the entrance / exit 120 to carry the transported article into station 1 (S13: YES), the process proceeds to step S14. On the other hand, if the AMR 2 is not entering the entrance / exit 120 to carry the transported article into station 1, that is, if the AMR 2 is entering the entrance / exit 120 to carry the transported article out of station 1 (S13: NO), the process proceeds to step S15.

[0057] Here, the method for determining whether AMR 2 is carrying in or carrying out an article can be determined by determining whether AMR 2 is carrying in an article. Specifically, control unit 21 determines whether AMR 2 is carrying in an article, and if it is carrying in an article, determines that AMR 2 will enter entrance / exit 120 to carry in the article to station 1. On the other hand, if AMR 2 is not carrying in an article, determines that AMR 2 will enter entrance / exit 120 to carry out the article from station 1.

[0058] Furthermore, whether the AMR 2 is carrying an object can be determined by checking whether the lifter 27 is raised. The lifter 27 is always raised when an object is loaded, and is always lowered when no object is loaded. The lifter 27 is also provided with a limit switch that turns ON when the lifter 27 is raised, and the control unit 21 determines that the lifter 27 is raised when the limit switch is ON. On the other hand, the control unit 21 determines that the lifter 27 is lowered when the limit switch is OFF.

[0059] Therefore, the control unit 21 determines that the transported object is loaded when the limit switch is ON and the lifter 27 is rising, and determines that the transported object is not loaded when the limit switch is OFF and the lifter 27 is falling.

[0060] As a result, when the limit switch is ON, the control unit 21 determines that the AMR 2 will enter the entrance / exit 120 to carry the transported item into station 1. On the other hand, when the limit switch is OFF, the control unit 21 determines that the AMR 2 will enter the entrance / exit 120 to carry the transported item out of station 1.

[0061] In step S14, the control unit 21 determines to cause the AMR 2 to advance and enter the entrance / exit opening 120. As shown in Fig. 10A, when the AMR 2 carries in the pallet 5, i.e., when the AMR 2 is loaded with the pallet 5, the AMR 2 is caused to enter the station 1 from the front where the bogie mechanism is provided. This allows the AMR 2 to always obtain a stable driving force when loading the pallet 5 and entering the station 1, even if it runs over a foreign object.

[0062] After stopping at the parking space Ps, the AMR 2 lowers the lifter 27 to place the pallet 5 on the support part 110, as shown in Fig. 10B, and exits through the entrance / exit gate 120. At this time, the AMR 2 retreats to exit, but since it no longer has the pallet 5 loaded, it can travel backward without any problems, even if it does not have a bogie mechanism.

[0063] In step S15, the control unit 21 determines to cause the AMR 2 to reverse and enter the entrance / exit 120. As shown in Fig. 11A, the AMR 2 reverses and enters the entrance / exit 120, but because it does not carry a pallet 5, it can travel backward without any problems even if it does not have a bogie mechanism.

[0064] After stopping at the parking space Ps, the AMR 2 raises the lifter 27 to load the pallet 5, as shown in Figure 11B, and exits through the entrance / exit gate 120. At this time, the AMR 2, which is equipped with a bogie mechanism, travels forward to exit the station 1, so that a stable driving force can always be obtained even if the AMR 2 runs over a foreign object.

[0065] In step S16, the control unit 21 searches for the first and second entrance reflectors 140, 141 using the front sensor 23a or the rear sensor 23b.

[0066] In step S17, the control unit 21 determines the relative positions of the first and second approach reflectors 140, 141 with respect to the AMR 2 from the information on the first and second approach reflectors 140, 141 detected by the sensor 23a or the sensor 23b. From the point cloud data detected by the sensors 23a and 23b, the distances from the AMR 2 (sensors 23a and 23b) to the first and second approach reflectors 140, 141 and the angles of the first and second approach reflectors 140, 141 as seen from the AMR 2 (sensors 23a and 23b) are determined. The control unit 21 determines the relative positional relationship between the first and second approach reflectors 140, 141 from the distances and angles.

[0067] In step S18, the control unit 21 calculates the drive amounts of the pair of drive motors 24a, 24b from the relative positional relationship between the first and second entrance reflectors 140, 141. As shown in Fig. 12, the control unit 21 calculates the drive amounts of the pair of drive motors 24a, 24b so that the center Ct of the AMR 2 coincides with a reference position Rp, for example, a central position, defined between the first and second entrance reflectors 140, 141. The control unit 21 then controls the drive motors 24a, 24b in accordance with the calculated drive amounts to move the AMR 2 forward or backward.

[0068] In step S19 shown in Fig. 7, the control unit 21 determines whether the AMR 2 has reached the approach position Pap. As shown in Fig. 12, the approach position Pap is set a certain distance La before the entrance / exit 120 of the parking space Ps. As shown in Fig. 7, if the control unit 21 determines that the AMR 2 has not reached the approach position Pap (S19: NO), the control unit 21 performs the processes of steps S20 and S21 and then performs the process of step S19 again. On the other hand, if the control unit 21 determines that the AMR 2 has reached the approach position Pap (S19: YES), the control unit 21 performs the process of step S22, which will be described later.

[0069] In step S20, the control unit 21 uses the sensor 23a or the sensor 23b to check the positions of the first and second entrance reflectors 140, 141 while driving the AMR 2. Then, in step S21, the control unit 21 corrects the drive amounts of the pair of drive motors 24a, 24b. Then, the control unit 21 controls the drive motors 24a, 24b in accordance with the corrected drive amounts to move the AMR 2 forward or backward.

[0070] 12 , when the AMR2 is shifted to the right from the reference position Rp, the control unit 21 corrects the drive amounts of the pair of drive motors 24a, 24b so that the drive amount of the right drive motor 24b is greater than the drive amount of the left drive motor 24a. On the other hand, when the AMR2 is shifted to the left from the reference position Rp, the control unit 21 corrects the drive amounts of the pair of drive motors 24a, 24b so that the drive amount of the left drive motor 24a is greater than the drive amount of the right drive motor 24b. Furthermore, when the reference position Rp and the AMR2 are roughly aligned, the control unit 21 corrects the drive amounts of the pair of drive motors 24a, 24b so that the drive amounts of the left and right drive motors 24a, 24b are aligned.

[0071] In this way, by adjusting the drive amounts of the pair of drive motors 24a, 24b while the AMR 2 approaches the approach position Pap, the center Ct of the AMR 2 can be moved closer to the reference position Rp. The AMR 2 can change its course according to the difference in rotational speed between the drive wheels 25a, 25b, rather than by steering the pair of drive wheels 25a, 25b. Therefore, as the AMR 2 approaches the approach position Pap, it moves forward while snaking left and right.

[0072] 8, the control unit 21 uses the sensor 23a or the sensor 23b to search for the left wall 130 of the station 1. In step S23, the control unit 21 determines whether the left wall 130 of the station 1 has been searched for. If the left wall 130 has not been searched for (S23: NO), the control unit 21 performs the process of step S24 and then performs the process of step S23 again. On the other hand, if the left wall 130 has been searched for (S23: YES), the control unit 21 performs the process of step S25.

[0073] In step S24, the control unit 21 calculates the drive amounts of the pair of drive motors 24a, 24b to move the AMR 2 forward or backward. When the AMR 2 is within a range where the first and second entrance reflectors 140, 141 can be detected by the sensors 23a, 23b, the control unit 21 calculates the drive amounts of the pair of drive motors 24a, 24b based on the relative positions of the first and second entrance reflectors 140, 141. On the other hand, as shown in FIG. 12 , when the AMR 2 moves forward or backward and the first and second entrance reflectors 140, 141 can no longer be detected by the sensor 23a or the sensor 23b, the control unit 21 calculates the drive amounts of the pair of drive motors 24a, 24b so that the AMR 2 moves straight forward.

[0074] In step S25 shown in Fig. 8, the control unit 21 calculates the drive amounts of the pair of drive motors 24a, 24b based on information about the left wall 130. As shown in Fig. 13, the control unit 21 calculates the drive amounts of the pair of drive motors 24a, 24b so that the distance dsw between the AMR 2 and the left wall 130 becomes a predetermined reference value. Then, the control unit 21 controls the drive motors 24a, 24b in accordance with the calculated drive amounts to move the AMR 2 forward or backward.

[0075] 8, the control unit 21 searches for the stopping reflector 145 using the sensor 23a or the sensor 23b, and determines whether the stopping reflector 145 has been found by the sensor 23a or the sensor 23b. If the stopping reflector 145 has not been found (S26: NO), the control unit 21 performs the processes of steps S27 and S28, and then performs the process of step S26 again. On the other hand, if the stopping reflector 145 has been found (S26: YES), the control unit 21 performs the process of step S29.

[0076] In step S27, while moving the AMR 2, the control unit 21 uses the sensor 23a or the sensor 23b to check the distance dsw to the left wall 130. Then, in step S28, the control unit 21 corrects the drive amounts of the pair of drive motors 24a, 24b so that the distance dsw between the AMR 2 and the left wall 130 becomes a reference value.

[0077] 13, when the distance dsw between the AMR2 and the left wall 130 is greater than the reference value, the AMR2 travels along a course toward the left wall 130 so that the distance dsw approaches the reference value. As the distance dsw approaches the reference value, the orientation of the AMR2 approaches being parallel to the front-to-rear direction.

[0078] In step S29 shown in Fig. 8, the control unit 21 determines whether the position of the stopping reflector 145 as seen from the AMR 2 is within an appropriate range. As shown in Fig. 13, the distance dm from the AMR 2 to the stopping reflector 145 and the angle θc of the stopping reflector 145 as seen from the AMR 2 are detected by the sensor 23a or the sensor 23b. The control unit 21 determines that the position of the stopping reflector 145 is within the appropriate range when the distance dm is equal to or less than a predetermined judgment distance and the angle θc is equal to or greater than a predetermined judgment angle.

[0079] If the position of the stopping reflector 145 is not within the appropriate range (S29: NO), the control unit 21 performs the processes of steps S30 and S31, and then performs the process of step S29 again. On the other hand, if the position of the stopping reflector 145 is within the appropriate range (S29: YES), the control unit 21 performs the process of step S32.

[0080] In step S30, the control unit 21 uses the sensor 23a or the sensor 23b to check the position of the stopping reflector 145 while running the AMR 2. Then, in step S31, the control unit 21 corrects the drive amounts of the pair of drive motors 24a, 24b so that the position of the stopping reflector 145 is within an appropriate range.

[0081] In step S32, the control unit 21 stops the pair of drive motors 24 a, 24 b to stop the travel of the AMR 2. When the AMR 2 stops in the specified position and in the specified orientation in the parking space Ps, the station entry process according to this embodiment ends.

[0082] [Effects of the First Embodiment] As described above in detail, in the conveying system according to this embodiment, when the AMR 2 enters the entrance / exit opening 120 to carry an article into station 1, it advances to enter the entrance / exit opening 120, and when it enters the entrance / exit opening 120 to carry an article out of station 1, it retreats to enter the entrance / exit opening 120. As a result, since the AMR 2 always advances when an article is loaded, a stable driving force can always be obtained when an article is loaded, even if a bogie mechanism is provided only on the front side. Furthermore, since there is no need to provide a bogie mechanism on the rear side, it is possible to prevent an increase in costs due to an increase in the number of parts.

[0083] Furthermore, in the conveyance system according to this embodiment, AMR 2 determines whether or not it is carrying an article, and if it is carrying an article, it determines that it is entering the entrance / exit opening 120 to carry the article into station 1, and advances to enter entrance / exit opening 120, whereas if it is not carrying an article, it determines that it is entering the entrance / exit opening 120 to carry the article out of station 1, and retreats to enter entrance / exit opening 120. This allows AMR 2 to accurately determine whether it is carrying the article into or out of station 1.

[0084] Furthermore, in the conveying system according to this embodiment, the AMR 2 is provided with a lifter 27 that is placed on the AMR 2 and moves up and down, the lifter 27 rises when an object is placed on the AMR 2 and lowers when an object is not placed on the AMR 2, and when the lifter 27 is raised, it is determined that an object is placed on the AMR 2 and when the lifter 27 is lowered, it is determined that an object is not placed on the AMR 2. This makes it possible to accurately determine whether or not the AMR 2 is carrying an object on the AMR 2 by the lifter 27 rising or falling.

[0085] Second Embodiment A second embodiment to which the present disclosure is applied will be described below with reference to the drawings. In the description of the drawings, the same parts are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0086] As shown in FIG. 14, the AMR 2 according to this embodiment differs from the first embodiment in that it includes a transported object detection sensor 50 that detects a transported object placed on the support portion 110.

[0087] Station 1 is equipped with a support section 110 on which a pallet 5 is placed above a parking space Ps where an AMR 2 entering through an entrance / exit 120 stops. The pallet 5 placed on the support section 110 is located above the entrance / exit 120 as shown in FIG. 14 , and therefore can be detected by the transported article detection sensor 50. Therefore, the control section 21 determines whether the transported article detection sensor 50 has detected an article placed on the support section 110.

[0088] Then, when the transported object detection sensor 50 does not detect the transported object placed on the support section 110, the control section 21 determines that the transported object loaded on the AMR 2 will enter the entrance / exit opening 120 to carry it into station 1, and moves forward to enter the entrance / exit opening 120. On the other hand, when the transported object detection sensor 50 detects the transported object placed on the support section 110, the control section 21 determines that the transported object placed on the support section 110 will enter the entrance / exit opening 120 to carry it out of station 1, and moves backward to enter the entrance / exit opening 120.

[0089] The transported object detection sensors 50 are installed in front and behind the AMR 2 and are sensors that detect objects in front of or behind the AMR 2, such as a stereo camera, LiDAR, or TOF sensor. Furthermore, if the sensors 23a and 23b are set so as to be able to detect the pallet 5 placed on the support portion 110, the sensors 23a and 23b may be used as the transported object detection sensors 50.

[0090] [Station Entry Processing] Next, the station entry processing by the AMR 2 according to this embodiment will be described. In this embodiment, the processing of steps S13 to S15 in Figure 7 differs from that of the first embodiment, but the other steps are the same as those of the first embodiment. Therefore, detailed description of steps other than steps S13 to S15 will be omitted.

[0091] 7, the control unit 21 determines whether the AMR 2 is entering the entrance / exit 120 to carry the transported article into station 1. If the AMR 2 is entering the entrance / exit 120 to carry the transported article into station 1 (S13: YES), the process proceeds to step S14. On the other hand, if the AMR 2 is not entering the entrance / exit 120 to carry the transported article into station 1, that is, if the AMR 2 is entering the entrance / exit 120 to carry the transported article out of station 1 (S13: NO), the process proceeds to step S15.

[0092] In this embodiment, the method of determining whether the AMR 2 is carrying in or carrying out an object is determined based on whether the object detection sensor 50 detects an object placed on the support section 110. Specifically, the control section 21 determines whether the object detection sensor 50 detects a pallet 5 placed on the support section 110, and if the pallet 5 placed on the support section 110 is not detected, determines that the AMR 2 will enter the entrance / exit opening 120 to carry the object loaded on the AMR 2 into station 1. On the other hand, if the object detection sensor 50 detects a pallet 5 placed on the support section 110, determines that the AMR 2 will enter the entrance / exit opening 120 to carry the pallet 5 placed on the support section 110 out of station 1.

[0093] In step S14, the control unit 21 determines to cause the AMR 2 to advance and enter the entrance / exit opening 120. As shown in Fig. 10A, when the transported object detection sensor 50 does not detect the pallet 5 placed on the support unit 110, it is time for the AMR 2 to load and carry in an object, so the AMR 2 is caused to enter station 1 from the front, where the bogie mechanism is provided. This allows the AMR 2 to always obtain a stable driving force when loading and entering station 1, even if it steps on a foreign object.

[0094] After stopping at the parking space Ps, the AMR 2 lowers the lifter 27 to place the pallet 5 on the support part 110, as shown in Figure 10B, and exits through the entrance / exit gate 120. At this time, the AMR 2 retreats to exit, but since it no longer has any transported goods loaded on it, it can travel backward without any problems, even if it does not have a bogie mechanism.

[0095] In step S15, the control unit 21 determines to cause the AMR 2 to move backward and enter the entrance / exit opening 120. As shown in Fig. 11A, when the transported article detection sensor 50 detects the pallet 5 placed on the support section 110, the AMR 2 is not carrying any articles, and therefore can move backward without any problems even if it does not have a bogie mechanism.

[0096] After stopping at the parking space Ps, the AMR 2 raises the lifter 27 to load the pallet 5, as shown in FIG. 11B, and exits through the entrance / exit gate 120. At this time, the AMR 2 exits the station 1 from the front, which is equipped with a bogie mechanism, so that a stable driving force can always be obtained even if the AMR 2 runs over a foreign object. After this, the processing from step S16 onwards is performed, and the station entry processing according to this embodiment is completed.

[0097] [Effects of Second Embodiment] As described above in detail, in the conveying system according to this embodiment, the conveyed object detection sensor 50 determines whether or not a conveyed object placed on the support unit 110 has been detected, and if a conveyed object placed on the support unit 110 has not been detected, it determines that the conveyed object loaded on the AMR 2 will enter the entrance / exit opening 120 to carry it into station 1, and the AMR 2 advances and enters the entrance / exit opening 120. On the other hand, if a conveyed object placed on the support unit 110 has been detected, it determines that the conveyed object placed on the support unit 110 will enter the entrance / exit opening 120 to carry it out of station 1, and the AMR 2 retreats and enters the entrance / exit opening 120. This allows the AMR 2 to accurately determine whether to carry the conveyed object into or out of station 1.

[0098] Although the embodiments of the present disclosure have been described above, the descriptions and drawings that form part of this disclosure should not be understood to limit the present invention. Various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art from this disclosure.

[0099] The disclosure of this application is related to the subject matter described in Japanese Patent Application No. 2023-111579, filed on July 6, 2023, the entire disclosure of which is incorporated herein by reference.

Claims

1. A transport system comprising: a transport vehicle which autonomously controls its driving to transport an item; and a station into which the item is loaded or unloaded by the transport vehicle and which has an entrance / exit through which the transport vehicle enters and exits, wherein the transport vehicle has: a drive wheel provided in the center of the fore-and-aft direction of the body; driven wheels provided at the front and rear of the body, respectively; and a bogie mechanism connecting the drive wheel and the front driven wheel of the body with a connecting member rotatably provided on the body, wherein when the item is to be transported and entering the entrance / exit to be loaded into the station, the transport vehicle advances to enter the entrance / exit, and when the item is to be transported and leaving the station, the transport vehicle retreats to enter the entrance / exit.

2. The conveying system described in claim 1, wherein the conveying vehicle determines whether or not it is carrying the transported item, and if it is carrying the transported item, determines that it is entering the entrance / exit to bring the transported item into the station, and moves forward to enter the entrance / exit, and if it is not carrying the transported item, determines that it is entering the entrance / exit to remove the transported item from the station, and moves backward to enter the entrance / exit.

3. The transport system described in claim 2, wherein the transport vehicle is equipped with a lifting mechanism that lifts and lowers the transported object when the transported object is placed on the transport vehicle, the lifting mechanism rises when the transported object is placed on the transport vehicle and lowers when the transported object is not placed on the transport vehicle, and when the lifting mechanism is raised, it is determined that the transported object is loaded on the transport vehicle and when the lifting mechanism is lowered, it is determined that the transported object is not loaded on the transport vehicle.

4. The conveying system described in claim 1, wherein the station is provided with a support section on which the transported item is placed above a parking space where the transport vehicle entering through the entrance / exit is stopped, the conveying vehicle is provided with a sensor for detecting the transported item placed on the support section, and the sensor determines whether or not the transported item placed on the support section has been detected, and if the sensor does not detect the transported item placed on the support section, the conveying vehicle determines that the transported item loaded on the conveying vehicle will enter the entrance / exit to be transported into the station, and advances to enter the entrance / exit, and if the sensor detects the transported item placed on the support section, the conveying vehicle determines that the transported item loaded on the support section will enter the entrance / exit to be transported out of the station, and retreats to enter the entrance / exit.

5. A transport vehicle which autonomously controls its travel to transport goods to or from a station equipped with an entrance / exit, comprising: a drive wheel provided in the center of the fore-and-aft direction of the vehicle body; driven wheels provided at the front and rear of the vehicle body, respectively; and a bogie mechanism connecting the drive wheel and the driven wheel at the front of the vehicle body with a connecting member rotatably provided on the vehicle body, wherein the transport vehicle advances to enter the entrance / exit when entering the entrance / exit to transport the goods to the station, and retreats to enter the entrance / exit when entering the entrance / exit to transport the goods from the station.

6. A station entry method for allowing a transport vehicle, which autonomously controls its driving to transport an article, to enter a station, wherein the station has an entrance / exit through which the article is loaded or unloaded by the transport vehicle and through which the transport vehicle enters and exits, the transport vehicle has a drive wheel provided in the center of the fore-and-aft direction of the vehicle body, driven wheels provided at the front and rear of the vehicle body, and a bogie mechanism connecting the drive wheel and the front driven wheel of the vehicle body with a connecting member rotatably provided on the vehicle body, wherein when the transport vehicle enters the entrance / exit to load the article into the station, the transport vehicle is caused to advance into the entrance / exit, and when the transport vehicle enters the entrance / exit to unload the article from the station, the transport vehicle is caused to retreat into the entrance / exit.

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