Conveyance vehicle

Abstract

[Problem] To suitably adjust a detection area of a sensor for detecting an object, without physically adjusting the orientation of the sensor. [Solution] A conveyance vehicle comprises: a travel unit that travels on a track; a body unit that is coupled with the travel unit and moves by the travel of the travel unit; a lifting platform that has a holding unit for holding an article and is capable of being lifted and lowered with respect to the body unit; a lifting drive unit that lifts and lowers the lifting platform by unwinding and winding a flexible suspension member; a lateral protrusion mechanism that causes the lifting drive unit to protrude toward a lateral side of the body unit in a cantilevered state; a sensor that is provided to the lifting drive unit and is capable of detecting the presence or absence of an object that may interfere with the delivery of the article in a prescribed area near the lowering destination of the lifting platform; and a setting unit that sets a detection area of the sensor, which is a part of the prescribed area. The sensor detects the presence or absence of an object in the detection area set by the setting unit.

Description

Transport vehicle

[0001] The present invention relates to a transport vehicle.

[0002] Conventionally, transport vehicles that travel along a track and convey articles are known. Patent Document 1 discloses a transport vehicle that includes an elevation drive unit for elevating and lowering an elevating platform holding an article relative to a main body, and a laterally-extending mechanism that projects the elevation drive unit to the side of the main body in a cantilevered state, wherein a sensor for detecting an object existing in the vicinity of a lowering destination of the elevating platform is provided on the elevation drive unit. In Patent Document 1, since deflection occurs due to the weight of the elevation drive unit during operation of the laterally-extending mechanism, a technique is disclosed that physically adjusts the orientation of the sensor provided on the elevation drive unit by a correction mechanism in accordance with the laterally-extending amount of the elevation drive unit by the laterally-extending mechanism and the lowering amount of the elevating platform.

[0003] Japanese Patent No. 7338640

[0004] In the above prior art, it may be difficult to appropriately adjust the orientation of the sensor due to restrictions on the operating range of the correction mechanism, and furthermore, if a failure occurs in the correction mechanism, the orientation of the sensor can no longer be adjusted.

[0005] The present invention provides a transport vehicle that can suitably adjust the detection area of a sensor that detects an object without physically adjusting the orientation of the sensor.

[0006] In an aspect of the present invention, there is provided a transport vehicle comprising: a traveling unit that travels along a track; a main body connected to the traveling unit and moved by travel of the traveling unit; an elevating platform that has a holding unit for holding an article and is capable of elevating and lowering relative to the main body; an elevation drive unit that elevates and lowers the elevating platform by feeding out and winding up a flexible suspension member; a laterally-extending mechanism that projects the elevation drive unit to a side of the main body in a cantilevered state; a sensor provided on the elevation drive unit, the sensor being capable of detecting the presence or absence of an object that may hinder delivery of an article in a predetermined region near the lowering destination of the elevating platform; and a setting unit that sets a detection area of the sensor which is a part of the predetermined region, wherein the sensor detects the presence or absence of an object in the detection area set by the setting unit.

[0007] According to the transport vehicle of the present invention, the sensor's detection area is set to a part of a predetermined area near the destination of the lowering platform, and the presence or absence of an object that could obstruct the transfer of goods is detected in the set detection area. Therefore, the sensor's detection area can be suitably adjusted without physically adjusting the orientation of the sensor that detects objects.

[0008] Furthermore, in the above embodiment of the transport vehicle, the setting unit may set a detection area that is narrower than a predetermined area in a plan view. According to this embodiment, object detection can be performed efficiently. Furthermore, in the above embodiment of the transport vehicle, the sensor may output a linear or band-shaped detection wave in a direction intersecting the direction in which the lifting drive unit protrudes. According to this embodiment, the accuracy of object detection can be increased. Furthermore, in the above embodiment of the transport vehicle, a control unit may be provided that outputs a lateral extension amount, which is the amount by which the lifting drive unit is extended by the lateral extension mechanism, and the setting unit may set the detection area according to the lateral extension amount output by the control unit. According to this embodiment, by suitably setting the range of the detection area, the efficiency of the object detection process can be greatly increased.

[0009] Furthermore, in the above-described transport vehicle, the sensor may identify the position of the edge of the loading area where goods are transferred based on the detection results in a predetermined area, and the setting unit may set the detection area based on the identified position of the edge of the loading area. According to this embodiment, by setting a detection area that does not include the loading area or a detection area that is not separated from the loading area, the detection process by the sensor can be performed efficiently, and false detections and missed detections by the sensor can be suppressed. In addition, in the above-described transport vehicle, the sensor may use a reference value corresponding to the height of the loading area where goods are transferred to detect the presence or absence of an object that is taller than the reference value. According to this embodiment, the detection accuracy of objects that may obstruct the transfer of goods can be further improved.

[0010] This figure shows an example of a transport vehicle according to the first embodiment. This is a perspective view showing an example of a side-dispensing mechanism according to the first embodiment. This figure illustrates an example of detection by a sensor according to the first embodiment. This is a flowchart illustrating an example of the object detection process according to the first embodiment. This figure illustrates an example of detection by a sensor according to the second embodiment. This is a flowchart illustrating an example of the object detection process according to the second embodiment. This figure illustrates an example of detection by a sensor according to the third embodiment. This is a flowchart illustrating an example of the object detection process according to the third embodiment.

[0011] Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to what is described below. The following embodiments do not limit the invention as defined in the claims. In the drawings, the scale may be appropriately changed, such as by enlarging, reducing, or emphasizing parts of the drawings, in order to explain the embodiments. Also, in the drawings, directions in the figures may be explained using the XYZ Cartesian coordinate system. In the XYZ Cartesian coordinate system, the vertical direction is the Z direction, and the horizontal directions are the X and Y directions. In the X, Y, and Z directions, the direction pointed to by the arrow is the + direction, and the opposite direction pointed to by the arrow is the - direction. Furthermore, the direction of rotation around the X axis is denoted as the θX direction, the direction of rotation around the Y axis is the θY direction, and the direction of rotation around the Z axis is the θZ direction.

[0012] [First Embodiment] Figure 1 is a diagram showing an example of a transport vehicle according to the first embodiment. As shown in Figure 1, a transport system including a transport vehicle 100 is provided in a processing room PR such as a cleanroom. A processing device (semiconductor processing device), not shown, is placed on the floor of the processing room PR. Rails R, which are tracks for guiding the transport vehicle 100, are provided on the ceiling of the processing room PR. Rails R include a running rail and a power supply rail.

[0013] The transport vehicle 100 travels, for example, along a rail R in the +Y direction. The transport vehicle 100 transfers goods FP at a loading section S. The loading section S is, for example, a load port of a processing device. The transport vehicle 100 has a traveling section 10, a connecting section 30, a main body section 40, and a control unit 80. The control unit 80 controls the operation of each part of the transport vehicle 100. The control unit 80 may be provided in the main body section 40 or outside the main body section 40.

[0014] The running section 10 is positioned inside the rail R and has a plurality of rollers 11 that contact the inside surface (running surface) of the rail R, and a drive device 12 that rotates the plurality of rollers 11. The transport vehicle 100 has a power receiving section that receives power via a non-contact power supply line provided on a power supply rail provided along the rail R and supplies power to the drive section such as the main body 40 provided on the transport vehicle 100. The connecting section 30 is provided on the lower side (-Z side) of the running section 10 and connects the running section 10 and the main body 40.

[0015] The main body 40 has a transfer device 41. The transfer device 41 has a lifting platform 42, a lifting drive unit 43, a sensor 44, and a side-extension mechanism 45. The main body 40 is connected to the running unit 10 via a connecting unit 30. The main body 40 moves integrally with the running unit 10 along the rail R.

[0016] The lifting platform 42 is movable up and down relative to the main body 40 (movable in the Z direction). The lifting platform 42 has a gripper 42a as a holding part for holding an article FP. The article FP is, for example, a container for housing semiconductor wafers (FOUP: Front Opening Unified Pod), or a reticle pod for housing a reticle. The gripper 42a grips or releases a flange FPa provided on the top (+Z side) of the article FP.

[0017] The lifting drive unit 43 raises and lowers (moves in the Z direction) the lifting platform 42. The lifting drive unit 43 suspends the lifting platform 42 via, for example, a plurality (e.g., four) flexible belts (suspension members) 43a. The lifting drive unit 43 raises and lowers the lifting platform 42 by unwinding or winding the belts 43a.

[0018] The lifting drive unit 43 has a sensor 44. The sensor 44 is provided on the lifting drive unit 43 and can detect the presence or absence of an object OB (see Figure 3, etc.) in a predetermined area A1 near the destination of the lowering platform 42 that could obstruct the transfer of an object FP. For example, the sensor 44 is a 3D-LiDAR that acquires three-dimensional information by overlapping multiple laser beams in the vertical direction and rotating them in the horizontal direction. The range of the predetermined area A1 shown in Figure 1 is just an example, and it is not the case that detection is limited to the illustrated range. When using a 3D-LiDAR, it is also possible to detect a wider range than the illustrated range. Note that the sensor 44 is not limited to a 3D-LiDAR as long as it can acquire three-dimensional information (e.g., point cloud data, three-dimensional position information of each point) in the predetermined area A1.

[0019] The sensor 44 includes a sensor control unit 90 and a setting unit 91. The sensor control unit 90 controls the operation of the sensor 44. For example, the sensor control unit 90 controls the operation of the sensor 44 in response to a command from the control unit 80. The setting unit 91 sets the area to be detected by the sensor 44. For example, the setting unit 91 sets the detection area A2 of the sensor 44 (see Figure 3, etc.), which is part of a predetermined area A1. The detection area A2 may be predetermined. As a result, the sensor 44 detects the presence or absence of an object OB in the detection area A2 set by the setting unit 91. When the sensor control unit 90 detects an object OB in the detection area A2, it notifies the control unit 80 that an object OB has been detected. In response to the detection of an object OB, the control unit 80 stops the raising and lowering of the lifting platform 42, for example. The predetermined area A1 and the detection area A2 have a width that extends in the direction in which the lifting drive unit 43 protrudes (the direction of movement of the lateral extension mechanism 45).

[0020] Figure 2 is a perspective view showing an example of a side extension mechanism according to the first embodiment. The side extension mechanism 45 has a lifting drive unit 43 cantilevered and protruding to the side (X direction) of the main body 40. The side extension mechanism 45 has an upper section 51, a middle section 52, a lower section 53, and a drive device 54. The upper section 51 is provided on the upper side of the main body 40. The upper section 51 is fixed to the main body 40. The upper section 51 may be movable in the +X direction or -X direction, which is to the side of the main body 40, by a guide (not shown). The middle section 52 is attached to the lower side of the upper section 51. The middle section 52 moves in the +X direction or -X direction relative to the upper section 51 by a guide (not shown). The lower section 53 is attached to the lower side of the middle section 52. The lower section 53 moves in the +X direction or -X direction relative to the middle section 52. The middle section 52 and the lower section 53 are moved by the drive device 54.

[0021] The drive unit 54 performs a lateral extension operation according to the control of the control unit 80. The drive unit 54 drives the drive pulley with the drive motor, operates the belt that transmits power from the drive pulley, and the idler pulley that supports and guides the belt's drive, thereby moving the middle section 52 and the lower section 53 relative to the upper section 51. In addition, rails and linear guides guided by the rails are provided for the movement of the middle section 52 and the lower section 53. Figure 1 shows an example where the middle section 52 and the lower section 53 move to the +X side relative to the upper section 51, respectively. Figure 2 shows an example where the middle section 52 and the lower section 53 move to the -X side relative to the upper section 51, respectively. Thus, the middle section 52 and the lower section 53 can move to the +X side and the -X side, respectively, relative to the upper section 51. Furthermore, the upper section 51, middle section 52, and lower section 53 are not limited to being plate-shaped as shown in the figure, but may be rod-shaped members or frames made up of rod-shaped members. The drive device 54 also causes the middle section 52 and lower section 53 to extend laterally to a preset amount in the +X direction or -X direction, according to the instructions of the control unit 80. The drive device 54 also functions as a correction mechanism for adjusting the amount of lateral extension in the +X direction or -X direction.

[0022] As shown in Figure 1, a lifting drive unit 43 is attached to the lower surface of the lower section 53. A swivel drive unit (not shown) may be provided that allows the lifting drive unit 43 to swivel in the θZ direction relative to the lower section 53. Alternatively, a swivel drive unit (not shown) may be provided that allows the gripper 42a to swivel in the θZ direction relative to the lifting platform 42. When the middle section 52 and the lower section 53 are projecting to the side (-X side) of the main body 40, the lateral extension mechanism 45 bends downward as a whole due to the weight of the middle section 52 and the lower section 53, the lifting drive unit 43, the lifting platform 42, and the weight of the item FP, etc., causing the tip of the lower section 53 to move downward. At this time, the lifting drive unit 43 is tilted in the θY direction due to the tilt of the lower section 53. However, because the belt 43a is flexible, the lifting platform 42 is located vertically below the lifting drive unit 43 even when the lifting drive unit 43 is tilted in the θY direction. The amount of protrusion in the X direction by the lateral extension mechanism 45 varies depending on the position of the mounting section S. Also, the tilt of the lifting drive unit 43 in the θY direction varies according to the amount of protrusion in the X direction by the lateral extension mechanism 45.

[0023] The control unit 80 comprehensively controls the operation of the transport vehicle 100. Specifically, the control unit 80 comprehensively controls operations related to the transport vehicle 100, such as the travel of the transport vehicle 100, the raising and lowering of the lifting platform 42, the holding of the item FP by the gripper 42a, the lateral extension of the lifting drive unit 43 by the lateral extension mechanism 45, and detection by the sensor 44. For example, the control unit 80 drives the transport vehicle 100 to the vicinity of the loading area S for the transfer of the item FP, controls the lateral extension of the lifting drive unit 43 by the lateral extension mechanism 45, raises and lowers the lifting platform 42, and controls the holding of the item FP by the gripper 42a. At this time, the control unit 80 instructs the sensor 44 to start the detection process, receives the detection result from the sensor 44, and executes control according to the received detection result. The control unit 80 has an adjustment unit 81. The adjustment unit 81 adjusts the amount of lateral extension of the lifting drive unit 43 by the lateral extension mechanism 45, the amount of lateral extension of the lifting drive unit 43 by the lifting drive unit 43, and the amount of lateral movement of the lifting platform 42 by the lifting drive unit 43.

[0024] When the lateral extension mechanism 45 is extended laterally from the transport vehicle 100, the lateral extension mechanism 45 may deflect due to the weight of the lateral extension mechanism 45 itself, the weight of the lifting drive unit 43, the weight of the lifting platform 42, and the weight of the item FP. Due to the deflection of the lateral extension mechanism 45, the lifting platform 42 (item FP) will be shifted from directly above the mounting surface of the transfer position in the mounting section S. In this state, even if the lifting platform 42 (item FP) is lowered, the item FP will be placed off-center from the mounting surface of the transfer position.

[0025] Furthermore, the amount of deflection in the lateral extension mechanism 45 differs depending on whether the item FP is placed on the loading section S (during unloading) or when the item FP is received from the loading section S (during loading). Therefore, the appropriate amount of lateral extension required to position the lifting drive unit 43 directly above the transfer position differs. Accordingly, in order to compensate for the misalignment of the lifting drive unit 43, it is preferable to adjust the amount of lateral extension of the lifting drive unit 43 by the lateral extension mechanism 45, taking into account the deflection in the lateral extension mechanism 45. Therefore, the adjustment unit 81 adjusts the amount of lateral extension of the lifting drive unit 43 by the lateral extension mechanism 45, and the presence or absence of the item FP, according to the amount of lateral extension of the lifting drive unit 43 by the lateral extension mechanism 45 and the presence or absence of the item FP.

[0026] When the adjustment unit 81 adjusts the amount of lateral extension of the lifting drive unit 43 by the lateral extension mechanism 45, it adjusts the position of the middle section 52 and the lower section 53 in the X direction by adjusting the drive amount of the drive device 54, as shown in Figure 2. Due to the deflection of the lateral extension mechanism 45, the position of the lifting drive unit 43 in the X direction shifts to a position closer to the main body 40. Therefore, the adjustment unit 81 adjusts the position in the X direction for at least one of the middle section 52 and the lower section 53, and adjusts the position of the lifting drive unit 43 which is supported by the lower section 53. Figure 2 shows an example where the adjustment unit 81 moves the lower section 53 by a predetermined value ΔX toward the -X side from a state where the lateral extension mechanism 45 is extended laterally in the -X direction. When the lateral extension mechanism 45 is extended laterally in the +X direction, the adjustment unit 81 adjusts by moving the lower section 53 by a predetermined value toward the +X side.

[0027] Figure 3 illustrates an example of detection by a sensor according to the first embodiment. Figure 3 includes a placement section S where the item FP is transferred, and a floor surface FS on which the placement section S is located. Although the floor surface FS is shown as a specific area for illustrative purposes, it is the entire floor of the processing room PR and is not limited to the shown area. Furthermore, an example is given where the object OB (e.g., person, object, work robot, etc.) that the sensor 44 is detecting is included. As shown in Figure 3, the setting unit 91 sets a detection area A2 that is narrower than a predetermined area A1 in a plan view. As described above, the detection area A2 may be predetermined. Also, the detection area A2 does not need to reach the floor surface FS in the vertical direction (Z direction). As a result, the sensor 44 outputs a linear or band-shaped detection wave DW in the detection area A2 in a direction intersecting the direction in which the lifting drive unit 43 protrudes. The block arrows shown in Figure 3 represent the scanning direction of the detection wave DW. At this time, when the sensor control unit 90 detects object OB in the detection area A2 by the sensor 44, it notifies the control unit 80 that object OB has been detected. When the control unit 80 is notified by the sensor control unit 90 that object OB has been detected, it stops the raising and lowering of the lifting platform 42, for example.

[0028] Here, the detection area A2 may be set according to the amount of lateral extension of the lifting drive unit 43. As described above, the control unit 80 recognizes the amount of lateral extension of the lifting drive unit 43. Specifically, the control unit 80 outputs the amount of lateral extension, which is the amount by which the lifting drive unit 43 is extended by the lateral extension mechanism 45, to the sensor control unit 90. The setting unit 91 then sets the detection area A2 according to the amount of lateral extension of the lifting drive unit 43 output by the control unit 80. For example, the sensor control unit 90 holds information on the detection area A2 to be set in accordance with the amount of lateral extension of the lifting drive unit 43. The setting unit 91 then sets the detection area A2 corresponding to the amount of lateral extension of the lifting drive unit 43. Subsequently, when the sensor 44 detects an object OB in the detection area A2 corresponding to the amount of lateral extension of the lifting drive unit 43, the sensor control unit 90 notifies the control unit 80 that an object OB has been detected. When the control unit 80 is notified by the sensor control unit 90 that an object OB has been detected, it stops the raising and lowering of the lifting platform 42, for example.

[0029] Figure 4 is a flowchart showing an example of the object detection process flow according to the first embodiment. As shown in Figure 4, the sensor control unit 90 obtains the amount of lateral extension of the lifting drive unit 43 from the control unit 80 (step S101). Then, the setting unit 91 sets the detection area A2 of the sensor 44 according to the amount of lateral extension of the lifting drive unit 43 obtained by the sensor control unit 90 (step S102). Note that the setting unit 91 may set a predetermined detection area A2 instead of setting a detection area A2 corresponding to the amount of lateral extension. Subsequently, the sensor 44 detects the presence or absence of object OB in the detection area A2 set by the setting unit 91 (step S103). Here, when the sensor control unit 90 detects object OB in the detection area A2 by the sensor 44, it notifies the control unit 80 that object OB has been detected. When the control unit 80 is notified by the sensor control unit 90 that object OB has been detected, it stops the lifting and lowering of the lifting platform 42, for example.

[0030] As described above, the transport vehicle 100 sets a detection area A2 which is a part of a predetermined area A1 that the sensor 44 can detect, and detects the presence or absence of an object OB that may obstruct the transfer of goods FP in the set detection area A2. Therefore, the detection area A2 of the sensor 44 can be suitably adjusted without physically adjusting the orientation of the sensor 44 that detects the object OB. Furthermore, the transport vehicle 100 sets a detection area A2 corresponding to the amount that the lifting drive unit 43 extends laterally, and detects the presence or absence of an object OB that may obstruct the transfer of goods FP in the set detection area A2. Therefore, the range of the detection area A2 can be suitably set, and the efficiency of the object OB detection process can be increased.

[0031] [Second Embodiment] In the second embodiment, the same reference numerals are used for components similar to those in the embodiments described above, and detailed descriptions of similar components may be omitted.

[0032] Figure 5 illustrates an example of detection by a sensor according to the second embodiment. As shown in Figure 5, the sensor 44 identifies the position SE of the edge of the mounting section S where the item FP is transferred, based on the detection result in a predetermined area A1. Specifically, the sensor 44 identifies point cloud data of the mounting section S from the three-dimensional information obtained from the detection result in the predetermined area A1, and identifies the position SE of the edge of the mounting section S from the identified point cloud data. For example, the sensor 44 identifies point cloud data corresponding to the four sides of the mounting section S from the point cloud data of the upper surface portion of the mounting section S included in the predetermined area A1. Then, the sensor 44 identifies two sides that extend along the direction of travel of the transport vehicle 100, and identifies the point cloud data corresponding to the side closer to the main body 40 as the position SE of the edge of the mounting section S.

[0033] The setting unit 91 sets the detection area A2 based on the identified edge position SE of the mounting area S. Specifically, the setting unit 91 sets the detection area A2 so as not to include the mounting area S, based on the edge position SE of the mounting area S identified by the sensor 44. Subsequently, when the sensor 44 detects an object OB, the sensor control unit 90 notifies the control unit 80 that an object OB has been detected. When the control unit 80 is notified by the sensor control unit 90 that an object OB has been detected, it stops the raising and lowering of the lifting platform 42, for example.

[0034] Figure 6 is a flowchart showing an example of the object detection process flow according to the second embodiment. As shown in Figure 6, the sensor 44 identifies the position SE of the edge of the mounting part S (step S201). Specifically, the sensor 44 identifies the point cloud data of the mounting part S from the three-dimensional information obtained from the detection result of a predetermined area A1, and identifies the position SE of the edge of the mounting part S from the identified point cloud data. Then, the setting unit 91 sets the detection area A2 of the sensor 44 based on the position SE of the edge of the mounting part S (step S202). Specifically, the setting unit 91 sets the detection area A2 so as not to include the mounting part S, based on the position SE of the edge of the mounting part S identified by the sensor 44. Subsequently, the sensor 44 detects the presence or absence of object OB in the detection area A2 (step S203). Here, when the sensor control unit 90 detects object OB in the detection area A2 by the sensor 44, it notifies the control unit 80 that object OB has been detected. When the control unit 80 is notified by the sensor control unit 90 that an object OB has been detected, it stops the raising and lowering of the lifting platform 42, for example.

[0035] As described above, the transport vehicle 100 sets the detection area A2 based on the position SE of the edge of the mounting section S. By setting the detection area A2 that does not include the mounting section S, the sensor 44 can efficiently perform the object OB detection process. Furthermore, since the transport vehicle 100 sets the detection area A2 based on the position SE of the edge of the mounting section S, by setting the detection area A2 that does not separate from the mounting section S, false detections and missed detections by the sensor 44 can be suppressed.

[0036] [Third Embodiment] In the third embodiment, the same reference numerals are used for components similar to those in the embodiments described above, and detailed descriptions of similar components may be omitted.

[0037] Figure 7 illustrates an example of detection by a sensor according to the third embodiment. Figure 7 includes a mounting section S where an item FP is transferred, and an object OB. The height of the mounting section S from the floor surface FS is the mounting section height SH. The height of the object OB from the floor surface FS is the object height OBH. As shown in Figure 7, the sensor 44 uses a reference value corresponding to the mounting section height SH, which is the height of the mounting section S where the item FP is transferred, to detect the presence or absence of an object OB that is taller than or equal to the reference value. Hereinafter, the reference value will be referred to as the "reference value RV". For example, the reference value RV may be the same value as the mounting section height SH, or it may be a slightly lower value than the mounting section height SH. By setting the reference value RV to a slightly lower value than the mounting section height SH, greater safety can be ensured.

[0038] Specifically, after the setting unit 91 sets the detection area A2, the sensor 44 detects an object OB in the detection area A2 and calculates the object height OBH, which is the height of the object OB from the floor surface FS, from the three-dimensional information obtained from the detection result in the predetermined area A1 (or detection area A2). Then, if the object height OBH is greater than or equal to the reference value RV, the sensor 44 processes the object OB as an object OB that may obstruct the transfer of the item FP. Subsequently, when the sensor control unit 90 detects an object OB that may obstruct the transfer of the item FP, it notifies the control unit 80 that an object OB has been detected. When the control unit 80 is notified by the sensor control unit 90 that an object OB that may obstruct the transfer of the item FP has been detected, it stops the lifting and lowering of the lifting platform 42, for example.

[0039] Here, if the object height OBH is less than the reference value RV, the sensor 44 may process the object OB as an object OB that does not obstruct the transfer of the item FP. Alternatively, if the object height OBH is less than the reference value RV, the sensor 44 may output to the sensor control unit 90 that an object OB that does not currently obstruct the transfer of the item FP has been detected. At this time, the sensor control unit 90 notifies the control unit 80 that an object OB that does not currently obstruct the transfer of the item FP has been detected. The control unit 80 may output a warning (e.g., sound, light, etc.) in response to the detection of an object OB that does not currently obstruct the transfer of the item FP. That is, even if an object OB does not currently obstruct the transfer of the item FP, it is possible that it may obstruct the transfer of the item FP depending on future circumstances, such as when a person or work robot is crouching, so the control unit may output a warning to draw attention to the situation.

[0040] Figure 8 is a flowchart showing an example of the object detection process flow according to the third embodiment. As shown in Figure 8, after the setting unit 91 sets the detection area A2 (step S102 or step S202), the sensor 44 determines whether an object OB exists in the detection area A2 (step S301). Then, if an object OB exists in the detection area A2 (step S301: YES), the sensor 44 determines whether the object OB has a height greater than or equal to the reference value RV (step S302). Specifically, the sensor 44 calculates the object height OBH, which is the height of the object OB from the floor surface FS, from the three-dimensional information obtained from the detection result of a predetermined area A1 (or detection area A2), and determines whether the object height OBH is greater than or equal to the reference value RV.

[0041] At this time, if the object OB has a height greater than or equal to the reference value RV (step S302: YES), the sensor 44 processes the object OB as an object that may obstruct the transfer of the item FP (step S303). As a result, when the sensor control unit 90 detects an object OB that may obstruct the transfer of the item FP by the sensor 44, it notifies the control unit 80 that an object OB has been detected. In response to the detection of an object OB that may obstruct the transfer of the item FP, the control unit 80 stops the raising and lowering of the lifting platform 42, for example. On the other hand, if the object OB is not present in the detection area A2 (step S301: NO), the sensor 44 terminates processing. Also, if the object OB has a height less than the reference value RV (step S302: NO), the sensor 44 terminates processing.

[0042] As described above, the transport vehicle 100 processes objects OB detected in the detection area A2 whose object height OBH is equal to or greater than the reference value RV as objects OB that may obstruct the transfer of goods FP, thereby increasing the detection accuracy of objects OB that may obstruct the transfer of goods FP.

[0043] Although embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above embodiments. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above embodiments. Furthermore, such modified or improved forms are also included in the technical scope of the present invention. One or more of the requirements described in the above embodiments may be omitted. Also, the requirements described in the above embodiments can be combined as appropriate. In addition, the execution order of each process shown in this embodiment can be implemented in any order, as long as the output of the previous process is not used in the subsequent process. Furthermore, even if the operation in the above embodiments is described using "first," "next," "followed," etc. for convenience, it is not necessary to perform them in this order. Furthermore, to the extent permitted by law, the disclosures of Japanese Patent Application No. 2025-053689 and all documents cited in the above embodiments are incorporated into this text.

[0044] A1... Designated area A2... Detection area FP... Item FS... Floor surface OB... Object R... Rail (track) S... Mounting section 10... Travel drive unit 40... Transfer device 41... Main body 42... Lifting platform 42a... Gripper 43... Lifting drive unit 44... Sensor 45... Side-extension mechanism 51... Upper section 52... Middle section 53... Lower section 54... Drive unit 80... Control unit 81... Adjustment unit 90... Sensor control unit 91... Setting unit 100... Transport vehicle

Claims

1. A transport vehicle comprising: a running section that travels on a track; a main body section connected to the running section and moved by the movement of the running section; a lifting platform having a holding section for holding articles and being able to be raised and lowered relative to the main body section; a lifting drive section that raises and lowers the lifting platform by extending and retracting a flexible suspension member; a lateral extension mechanism that cantileveres the lifting drive section and causes it to protrude to the side of the main body section; a sensor provided on the lifting drive section that can detect the presence or absence of an object that may obstruct the transfer of articles in a predetermined area near the destination of the lowering of the lifting platform; and a setting section that sets a detection area for the sensor which is part of the predetermined area, wherein the sensor detects the presence or absence of an object in the detection area set by the setting section.

2. The transport vehicle according to claim 1, wherein the setting unit sets the detection area having a width narrower than the predetermined area in a plan view.

3. The transport vehicle according to claim 1, wherein the sensor outputs a linear or band-shaped detection wave in a direction intersecting the direction in which the lifting drive unit protrudes.

4. The transport vehicle according to claim 1, comprising a control unit that outputs a lateral extension amount which is the amount by which the lifting drive unit is extended by the lateral extension mechanism, and the setting unit sets the detection area according to the lateral extension amount output by the control unit.

5. The transport vehicle according to claim 1, wherein the sensor identifies the position of the end of the loading section where the articles are transferred based on the detection result in the predetermined area, and the setting unit sets the detection area based on the identified position of the end of the loading section.

6. The transport vehicle according to claim 1, wherein the sensor detects the presence or absence of an object having a height equal to or greater than the reference value, using a reference value corresponding to the height of the loading section where the articles are transferred.

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