Transport vehicle system

Abstract

This overhead transport vehicle system comprises: a plurality of ports; a travel rail; a transport vehicle; a teaching carriage that acquires teaching data by lowering a teaching unit to a port at a travel stop position corresponding to each of the plurality of ports; an imaging device that acquires an image used for positional deviation determination; a determination carriage having a determination unit that performs positional deviation determination on the basis of the image acquired by the imaging device, and an output unit that outputs the determination result of the determination unit; and a carriage controller that controls the transport vehicle, the teaching carriage, and the determination carriage. The carriage controller outputs, as specific ports, the ports determined to have positional deviation on the basis of the determination result output from the output unit.

Description

Transfer cart system

[0001] The present disclosure relates to a transfer cart system.

[0002] As a conventional ceiling transfer cart system, there is known a system including a ceiling transfer cart that transfers an object to be transferred, and a teaching unit used for teaching when the ceiling transfer cart transfers the object to be transferred to a transfer unit on which the object to be transferred is placed (for example, Patent Document 1). In this ceiling transfer cart system, teaching is performed by the ceiling transfer cart lowering the teaching unit to each transfer unit.

[0003] WO 2018 / 186021

[0004] In such a ceiling transfer cart system, for example, when an earthquake occurs, the track on which the ceiling transfer cart travels or the installation state of each transfer unit (each port) may shift. In this case, it is not easy to identify the port where the displacement has occurred, so it is necessary to perform teaching for all ports. However, until the teaching for all ports is completed, the operation of the factory having the ceiling transfer cart system must be stopped, and it is required to shorten the time required for teaching.

[0005] The present disclosure describes a ceiling transfer cart system capable of shortening the time required for teaching of the ceiling transfer cart system.

[0006] [1] One aspect of the present disclosure is an overhead transport vehicle system comprising: a plurality of transfer destinations; a track provided above the plurality of transfer destinations; a transport vehicle that travels along the track and transfers items to the plurality of transfer destinations; a teaching trolley that travels along the track and acquires teaching data used when the transport vehicle transfers items to the plurality of transfer destinations by lowering a teaching unit to the transfer destination at a travel stop position corresponding to each of the plurality of transfer destinations; a determination trolley that travels along the track and acquires data used for position deviation determination at a travel stop position; a determination unit that performs position deviation determination to determine whether the position indicated by the data acquired by the detection unit is deviated by a predetermined distance or more from the position indicated by predetermined position data stored in advance; and an output unit that outputs the determination result of the determination unit; and a trolley controller that controls the transport vehicle, the teaching trolley and the determination trolley, wherein the trolley controller outputs a transfer destination that has been determined to have a position deviation as a specific transfer destination based on the determination result output from the output unit.

[0007] In the overhead transport vehicle system of [1], the determination cart performs a position deviation determination to determine whether the position indicated by the data acquired by the detection unit is deviated by a predetermined distance or more from the position indicated by pre-stored predetermined position data. The cart controller outputs the transfer destinations determined to have a position deviation as specific transfer destinations based on the determination result output from the output unit of the determination cart. This allows, for example, teaching by the teaching cart to be performed only for the specific transfer destinations determined to have a position deviation, and teaching for transfer destinations determined to have no position deviation to be omitted. Therefore, the time required for teaching the overhead transport vehicle system can be reduced compared to the case where teaching is performed for all transfer destinations by the teaching cart.

[0008] [2] In the overhead transport vehicle system described in [1] above, the trolley controller may drive the teaching trolley to a stopping position corresponding to a specific transfer destination and acquire teaching data. In this case, the teaching trolley drives based on the control of the trolley controller and acquires teaching data automatically, so teaching can be performed more quickly than manual teaching. Therefore, the time required for teaching the overhead transport vehicle system can be shortened.

[0009] [3] In the overhead transport vehicle system described in [1] or [2] above, the trolley controller may create a travel route that passes through multiple specific transfer destinations via the shortest path, and have the teaching trolley travel along the travel route. In this case, teaching can be performed efficiently by having the teaching trolley move through multiple specific transfer destinations via the shortest path.

[0010] [4] In any one of the overhead transport vehicle systems described in [1] to [3] above, the transfer destination has a mark indicating a reference position, the detection unit is an imaging device that captures an image including the mark, the predetermined position data is data indicating the position of the mark, and the determination unit may perform position deviation determination based on the amount of deviation between the position of the mark indicated by the predetermined position data and the position of the mark in the image captured from the imaging device. In this case, for example, the determination unit performs position deviation determination by comparing the amount of deviation of the mark with a predetermined distance, so the setting of the predetermined distance in the determination unit can be changed relatively easily. That is, for example, if the determination cart has a retroreflective sensor and performs position deviation determination based on the presence or absence of retroreflective light from a reflector provided at the transfer destination, in order to change the predetermined distance (i.e., threshold), it is necessary to replace the reflector and change the size of the reflector, but replacing the reflectors at all transfer destinations takes a relatively long time. On the other hand, in this embodiment, only the setting of the predetermined distance in the determination unit is changed, so the predetermined distance can be easily changed.

[0011] [5] In any one of the overhead transport vehicle systems described in [1] to [3] above, the transfer destination may have a reflector with a reflection range of a predetermined distance, the detection unit may be a retroreflective sensor that detects retroreflective light from the reflector, and the determination unit may perform positional displacement determination based on the presence or absence of retroreflective light. In this case, positional displacement determination can be performed more easily than with positional displacement determination using an imaging device.

[0012] [6] In any one of the overhead transport vehicle systems described in [1] to [5] above, each transfer destination has a permissible amount of displacement of the item during transfer, and the predetermined distance used for positional displacement determination in the judgment trolley may be set to be smaller than the permissible amount of displacement during transfer. In this case, even if a transfer destination with a displacement of more than the predetermined distance is judged to have no positional displacement due to, for example, a measurement error in positional displacement determination, it is possible to prevent the displacement from exceeding the permissible amount of displacement during transfer.

[0013] According to this disclosure, the time required for teaching the overhead transport system can be reduced.

[0014] Figure 1 is a block diagram showing an overhead transport vehicle system according to one embodiment of the present disclosure. Figure 2 is a side view of the transport vehicle and teaching cart in Figure 1. Figure 3 is a side view of the judgment cart in Figure 1. Figure 4(a) is a reference image of a pre-stored mark. Figure 4(b) is an image of a mark captured during positional displacement determination. Figure 5 is a diagram showing an example of the positional displacement determination result output by the output unit of Figure 1. Figure 6 is a block diagram showing an overhead transport vehicle system according to a modified example. Figure 7 is a side view of the judgment cart according to a modified example. Figure 8(a) is a plan view showing the laser beam incident on the reflection range of the reflector. Figure 8(b) is a plan view showing the laser beam incident on the outside of the reflection range of the reflector.

[0015] Embodiments of this disclosure will be described below with reference to the drawings. In the description of the drawings, the same elements will be denoted by the same reference numerals, and redundant descriptions will be omitted. The terms "up" and "down" correspond to the vertical direction, upward and downward, respectively.

[0016] As shown in Figures 1 to 3, the overhead transport system 1 of this embodiment is applied, for example, to a cleanroom (semiconductor factory) where semiconductor devices are manufactured. The overhead transport system 1 comprises a plurality of ports 2 (transfer destinations), a running rail 3 (track), a plurality of transport vehicles 10, a teaching trolley 20, a judgment trolley 30 (inspection trolley), and a trolley controller 40. The overhead transport system 1 is a system for transporting items F to the plurality of ports 2 by having the transport vehicles 10 travel along the running rail 3.

[0017] Multiple ports 2 are provided, for example, in a processing device that performs various processes on semiconductor wafers. Multiple ports 2 are arranged in large numbers (e.g., 1000 or more) throughout the entire factory. Each port 2 has three positioning pins 2a on its upper surface 2b for placing an item F. The item F is placed at the position determined by the positioning pins 2a. Furthermore, each port 2 has a mark M on its upper surface 2b (Figure 4). The mark M is a reference point provided in advance for the judgment trolley 30, described later, to perform positional deviation determination. Therefore, the mark M indicates the reference position for performing positional deviation determination. In Figure 4, the shape of the mark M is shown as a star, but the shape of the mark M can be any shape, and the positioning pins may also serve the role of the mark M. In addition, in this embodiment, the item F and the positioning pins 2a are each provided with guide parts (not shown) that guide the positions of each other. These guide sections allow for a certain degree of relative displacement between the position of the transport vehicle 10 when it lowers the item F and the placement position of the item F on the port 2. At this time (when transferring the item F to the placement position), the allowable displacement of the item F relative to the placement position is, for example, about 10 mm. In other words, each port 2 has an allowable amount of displacement of the item F that can be tolerated when transferring the item F.

[0018] The overhead transport system 1 may be equipped with storage shelves suspended from the ceiling (not shown) or with storage shelves installed on the floor (not shown). "Storage shelves" are also called "buffers." The concept of "storage shelves" also includes automatic storage devices such as stockers. Multiple ports 2 may be provided on these storage shelves.

[0019] The travel rail 3 is provided above the multiple ports 2, and is laid, for example, near the ceiling of a cleanroom. The transport vehicle 10 travels along the travel rail 3 and transfers items F to the multiple ports 2. Specifically, the transport vehicle 10 transports items F, such as a cassette containing multiple semiconductor wafers (a so-called FOUP (Front Opening Unified Pod)), and transfers items F at the ports 2. Hereinafter, the direction parallel to the travel direction of the transport vehicle 10 will be defined as the X direction, the direction parallel to the horizontal plane and perpendicular to the travel direction of the transport vehicle 10 will be defined as the Y direction, and the direction parallel to the vertical direction will be defined as the Z direction.

[0020] The transport vehicle 10 comprises a traveling section 11, a lateral feeding section 12, a rotating section 13, a lifting section 14, a holding section 15, and a control unit 16 (Figure 2). The traveling section 11 travels along the traveling rail 3 by receiving power without contact from high-frequency current lines laid along the traveling rail 3. The lateral feeding section 12 moves the rotating section 13, the lifting section 14, and the holding section 15 along the Y direction. The rotating section 13 rotates the lifting section 14 and the holding section 15 in a horizontal plane. The lifting section 14 raises and lowers the holding section 15 relative to the port 2 by unwinding or winding up a plurality of belts 14a, each with a holding section 15 attached to its lower end. The holding section 15 has a pair of claw members 15a. The holding section 15 holds the article F by opening and closing the pair of claw members 15a.

[0021] The control unit 16 controls the operation of each part of the transport vehicle 10. Based on the set teaching data, the control unit 16 controls the operation of the transport vehicle 10 and transfers the object to be transported to port 2. The teaching data consists of control parameters (or transfer conditions) for transferring the object to be transported to port 2. The control unit 16 also controls the teaching operation when the teaching unit TU is attached to the transport vehicle 10.

[0022] The teaching trolley 20 performs teaching to acquire teaching data for each port 2 using the teaching unit TU described later. Here, teaching is the process of determining the difference between the position of the holding part 15 when the transport vehicle 10 stops at the predetermined position and the position where the holding part 15 of the transport vehicle 10 should be in order to place the item F at the placement position determined by the positioning pin 2a, while the transport vehicle 10 has stopped at a predetermined position on the travel rail 3 (for example, the travel stop position N described later) and the holding part 15 has been lowered by a certain distance. Based on the difference determined when transferring the item F, the transport vehicle 10 performs the transfer operation so as to eliminate any deviation from the placement position. In this embodiment, the teaching performed by the teaching trolley 20 is auto-teaching performed automatically by the trolley controller 40 described later.

[0023] The teaching trolley 20 has the same configuration as the transport vehicle 10, except that it grips the teaching unit TU (Figure 2). In other words, the teaching trolley 20 is a transport vehicle 10 that grips the teaching unit TU.

[0024] The teaching unit TU is an auto teaching unit (ATU) that automatically measures the positions of three positioning pins 2a installed on port 2, for example. When the transport vehicle 10 is stopped at the stopping position N on the travel rail 3, the teaching unit TU is lowered a certain distance and measures the positions of the positioning pins 2a using a detection device (camera, touch panel, etc.) mounted on the teaching unit TU, and acquires teaching data (amount of deviation from the mounting position (X direction, Y direction, Z direction, rotation direction)). Here, the stopping position N on the travel rail 3 is indicated by a white triangle mark in Figure 2. This is also the case in Figures 3 and 7. The teaching unit TU may also acquire teaching data by detecting the position of the positioning member (teaching plate) installed on port 2 using a detection device such as a distance measuring sensor.

[0025] The teaching trolley 20, while gripping the teaching unit TU, travels along the travel rail 3 and performs teaching by lowering the teaching unit TU to the transfer destination at each of the multiple port 2 corresponding travel stop positions N. In this way, the teaching trolley 20 acquires teaching data that will be used when the transport vehicle 10 transfers the item F to the multiple port 2.

[0026] The determination trolley 30 travels along the running rail 3. In this embodiment, as described later, the determination trolley 30 determines the positional displacement of each port 2 from the amount of positional displacement of the mark M on the reference image I0 and the captured image I1. In this embodiment, the determination trolley 30 determines the positional displacement of all ports 2. The determination trolley 30 also determines the positional displacement in the horizontal direction (i.e., the X direction and the Y direction). Note that the positional displacement determination is performed with a coarser positional accuracy and in a shorter time than the teaching described above.

[0027] As shown in Figures 1 and 3, the determination cart 30 includes a traveling unit 31, a lateral feed unit 32, an imaging device 33 (detection unit), a storage unit 34, a determination unit 35, an output unit 36, and a control unit 37 (Figures 1 and 3). The imaging device 33 may have the storage unit 34, determination unit 35, and output unit 36 ​​inside the imaging device 33. The traveling unit 31 and the lateral feed unit 32 have the same configuration as the traveling unit 11 and lateral feed unit 12 of the transport vehicle 10, respectively, so a description of their configurations will be omitted.

[0028] The imaging device 33 acquires images (data) at the stopping position N that the determination unit 35, described later, uses for positional deviation determination. The imaging device 33 captures images including the marks M of each port 2 at the stopping position N corresponding to each port 2. The imaging device 33 is, for example, a camera. In this embodiment, the imaging device 33 captures images that all have the same size (number of pixels). For example, the imaging device 33 captures the captured image I1 of each port 2 when positional deviation determination is performed (Figure 4(b)).

[0029] The storage unit 34 pre-stores a reference image I0 including the mark M for each port 2 as default position data. The reference image I0 including the mark M (Figure 4(a)) may be an image captured by the imaging device 33 of the judgment trolley in the previous or past, or it may be an image virtually set corresponding to each port 2 during system design. In this embodiment, the default position data is image data indicating the position of the mark M, but the default position data is not limited to image data. For example, the default position data may be coordinate data such as the design values ​​of the overhead transport vehicle system 1.

[0030] The determination unit 35 determines whether the position of each port 2 is shifted by a predetermined distance or more, based on the amount of deviation ΔP between the position P1 of the mark M on the captured image I1 and the position P0 (default position) of the mark M on the pre-stored reference image I0. Here, position P0 is the position of the mark M on the reference image I0. Position P1 is the position of the mark M on the captured image I1 captured by the imaging device 33 at the time the position deviation determination is performed. These images are captured by the imaging device 33 of the determination trolley 30 stopped at the travel stop position N. The predetermined distance is set to be smaller than the allowable deviation amount when port 2 is transferred, for example, 6 mm. Note that the predetermined distance may be set to any value other than 6 mm.

[0031] The determination unit 35 performs a positional misalignment determination based on the amount of deviation ΔP between the position P0 of the mark M indicated by the pre-stored reference image I0 and the position P1 of the mark M in the captured image I1 acquired from the imaging device 33. Hereinafter, "no positional misalignment" includes both the case where there is no positional misalignment (it is zero) and the case where the positional misalignment is small (the amount of positional misalignment is less than a predetermined distance). The method of positional misalignment determination by the determination unit 35 will be described below with reference to Figures 4(a) and (b).

[0032] First, as shown in Figure 4(a), the determination unit 35 acquires a reference image I0 that has been pre-stored in the storage unit 34. In the reference image I0, a mark M is shown at position P0 on the reference image I0. In this embodiment, for example, the mark M is located in the center of the reference image I0. Next, as shown in Figure 4(b), the determination unit 35 calculates the amount of displacement of the mark M on the captured image I1 by comparing the captured image I1 acquired from the imaging device 33 with the reference image I0. Specifically, it calculates the amount of displacement ΔP of position P1 of the mark M in the captured image I1 relative to position P0. In Figure 4(b), the position P0 of the mark M in the reference image is virtually shown by a dashed line, and the amount of displacement ΔP is determined based on the amount of displacement ΔPx in the X direction and the amount of displacement ΔPy in the Y direction.

[0033] The determination unit 35 converts the displacement amount ΔP of the mark M on the captured image I1 into the actual displacement amount on the upper surface 2b of the port 2. In this case, the scale (correspondence relationship) on the captured image I1 with respect to the distance on the upper surface of the port 2 is calculated in advance, and the actual displacement amount on the upper surface 2b of the port 2 is calculated based on this correspondence relationship. The actual displacement amount is determined, for example, based on the displacement amount in the X direction and the displacement amount in the Y direction. The displacement amount in the X direction and the displacement amount in the Y direction correspond to the displacement amounts ΔPx and ΔPy on the captured image I1, respectively. Hereinafter, the actual displacement amount on the upper surface 2b of the port 2 may be abbreviated as "actual displacement amount".

[0034] The determination unit 35 determines whether the actual amount of deviation is greater than or equal to a predetermined distance. If the determination unit 35 determines that the actual amount of deviation is greater than or equal to the predetermined distance, it determines that reteaching by the teaching trolley 20 is "necessary". If the determination unit 35 determines that the actual amount of deviation is less than the predetermined distance, it determines that reteaching by the teaching trolley 20 is "unnecessary".

[0035] As described above, in this embodiment, the determination unit 35 performs a positional deviation determination to determine whether the position P1 of the mark M indicated by the captured image I1 acquired by the imaging device 33 is deviated by a predetermined distance or more from the position P0 of the mark M indicated by the reference image I0 stored in advance. More specifically, the determination unit 35 calculates the actual deviation amount based on the deviation amount ΔP between the position P1 of the mark M indicated by the captured image I1 acquired by the imaging device 33 and the position P0 of the mark M indicated by the reference image I0 stored in advance, and determines whether the calculated actual deviation amount is greater than or equal to a predetermined distance.

[0036] The output unit 36 ​​outputs the determination result V (position deviation determination result) of the determination unit 35 to the trolley controller 40. As shown in Figure 5, the determination result V is, for example, for each port number n (n is 1 or more), the position data (ΔX ｎ ΔY ｎ This is a list that includes the actual amount of displacement, the time the positional displacement was determined, and the need for reteaching.

[0037] The control unit 37 controls the operation of each part of the determination trolley 30. The control unit 37 performs positional deviation determination, as described later, based on instructions from the trolley controller 40.

[0038] The trolley controller 40 controls the transport vehicle 10, the teaching trolley 20, and the judgment trolley 30. Furthermore, the trolley controller 40 controls the imaging device 33 (detection unit), the judgment unit 35, and the output unit 36 ​​in the judgment trolley 30.

[0039] The trolley controller 40 may pre-store images of each port 2 captured by the imaging device 33 of the judgment trolley 30 as reference images I0 in the storage unit 34, in conjunction with the timing when the teaching trolley 20 performed the previous teaching. Specifically, the control unit 37 of the judgment trolley 30 may pre-capture reference images I0 including the marks M of each port 2 using the imaging device 33 at the stopping position N of each port 2, and pre-store the captured images as reference images I0 in the storage unit 34.

[0040] The trolley controller 40 then instructs the control unit 37 of the judgment trolley 30 to perform a position displacement determination process for each port 2 if there is a possibility that the installation state of the ports 2 and the running rails 3 has shifted due to an earthquake or the like. In this embodiment, the trolley controller 40 creates a running path that passes through all ports 2 and assigns the running path to the judgment trolley 30, and also instructs the control unit 37 to perform a position displacement determination. The control unit 37 performs the position displacement determination process in accordance with the instructions of the trolley controller 40. This position displacement determination process does not have to be triggered by an earthquake, but may be performed periodically as maintenance of the overhead transport vehicle system 1 in order to detect changes over time. The position displacement determination process performed by the control unit 37 of the judgment trolley 30 will be described in detail below.

[0041] The control unit 37 first directs the determination trolley 30 towards the port 2 where the initial positional deviation determination is to be performed. Then, with the determination trolley 30 stopped at the travel stop position N of the port 2, the control unit 37 captures an image I1 including the mark M using the imaging device 33 (Figure 4(b)).

[0042] The control unit 37 causes the determination unit 35 to execute the misalignment determination. The control unit 37 determines whether the mark M on the port 2 is displaced by a predetermined distance or more by comparing the reference image I0 stored in advance at the time of the previous teaching implementation with the captured image I1.

[0043] After that, the control unit 37 causes the determination carriage 30 to face the port 2 for which the next misalignment determination is to be performed, and executes the same misalignment determination process as that for the first port 2. Specifically, the carriage controller 40 creates a travel route of the determination carriage 30 that passes through a plurality of travel stop positions N corresponding to all the ports 2 in the ceiling conveyance carriage system 1 via the shortest path, and causes the determination carriage 30 to travel along the travel route. The shortest path may be a path with the shortest path length or a path with the shortest travel time. The carriage controller 40 may cause the determination carriage 30 to execute the determination process in the order of arrangement of the ports 2 (sequentially for the arranged ports 2), or may create a different inspection schedule from the arrangement order and cause the determination carriage 30 to execute the determination process based on the schedule.

[0044] After that, the control unit 37 outputs the determination result V of the misalignment determination to the carriage controller 40 by the output unit 36.

[0045] After the above misalignment determination process is executed by the control unit 37, the carriage controller 40 outputs the port 2 determined to have misalignment (the necessity of re-teaching is "required") as a specific port SP (specific transfer destination) based on the determination result V output from the output unit 36. In this example, there are a plurality of specific ports SP.

[0046] After that, the carriage controller 40 causes the teaching carriage 20 to travel to the travel stop position N corresponding to the specific port SP, and performs a process (re-teaching) of acquiring teaching data for the specific port SP. Specifically, the carriage controller 40 creates a travel route of the teaching carriage 20 that passes through a plurality of travel stop positions N corresponding to the plurality of specific ports SP via the shortest path, and causes the teaching carriage 20 to travel along the travel route.

[0047] In the positional deviation determination by the determination carriage 30 as described above, compared to the teaching by the teaching carriage 20, for example, since the operation of lowering the teaching unit TU to port 2 is not performed, the positional deviation determination can be performed in a relatively short time.

[0048] Hereinafter, the effective time ΔT of the ceiling transfer cart system 1 in the present embodiment will be described. The effective time ΔT is an index that quantitatively indicates how much the time required for reteaching is shortened when using the ceiling transfer cart system 1 compared to the case of performing reteaching for all ports 2. Specifically, the effective time ΔT is the amount obtained by subtracting the time Td required for reteaching of the ceiling transfer cart system 1 from the time Ta required for performing reteaching for all ports 2 (Equation (5) described later). The larger the value of the effective time ΔT, the greater the effect of shortening the time required for teaching. The effective time ΔT is calculated by the following procedure. First, the time Ta is represented by the following equation (1). Ta: The time required for the teaching carriage 20 to perform reteaching for all ports 2. ta: The time required for the teaching carriage 20 to perform reteaching for one port 2. N: The number of all ports 2 (1500 in the present embodiment).

[0049] Next, the time Tb required to determine the positional deviation of all ports 2 is represented by the following equation (2). Here, as described above, since the determination carriage 30 does not perform the operation of lowering the teaching unit TU to port 2, the time tb required for the positional deviation determination is smaller than the time ta required for reteaching. Tb: The time required for the determination carriage 30 to determine the positional deviation of all ports 2. tb: The time required for the determination carriage 30 to determine the positional deviation of one port 2 (however, tb < ta).

[0050] Next, the time Tc required to perform reteaching only for the specific port SP is represented by the following equation. Tc: The time required for the teaching trolley 20 to perform reteaching only for specific ports SP. Nsp: The number of specific ports SP (the number of ports 2 determined to have a positional misalignment by the judgment trolley 30).

[0051] Next, the time Td required for teaching the overhead transport system 1 is given by the following equation (4). As shown in equation (4), time Td is the sum of the time Tb required to perform positional misalignment detection for all ports 2 and the time Tc required to perform reteaching only for a specific port SP. Td: Time required for teaching the overhead transport system 1.

[0052] Using equations (1) and (4) above, the effect time ΔT is given by the following equation (5). ΔT: Duration of effect.

[0053] Furthermore, by substituting equation (4) into equation (5), the effect duration ΔT is given by equation (6).

[0054] From equation (6), it can be seen that the effect time ΔT is larger as the time Tc required for reteaching decreases (i.e., as the number of specific port SPs Nsp decreases).

[0055] As described above, in the overhead transport vehicle system 1 of this embodiment, the determination cart 30 performs a position deviation determination to determine whether the position P1 of the mark M indicated by the captured image I1 acquired by the imaging device 33 is deviated by a predetermined distance or more from the position P0 of the mark M indicated by the reference image I0 that has been stored in advance. Based on the determination result V output from the output unit 36 ​​of the determination cart 30, the cart controller 40 outputs the port 2 that has been determined to have a position deviation as a specific port SP. As a result, for example, teaching by the teaching cart 20 can be performed only for the specific port SP that has been determined to have a position deviation, and teaching for the port 2 that has been determined not to have a position deviation can be omitted. Therefore, compared to the case in which teaching is performed by the teaching cart 20 for all ports 2, the time required for teaching the overhead transport vehicle system 1 (in this embodiment, the time required for re-teaching Td) can be shortened.

[0056] Furthermore, positional deviation detection using the judgment trolley 30 can be performed in a relatively short time compared to teaching using the teaching trolley 20, because it does not require lowering the teaching unit TU to port 2. Therefore, the time required for teaching the overhead transport system 1 can be reduced.

[0057] The trolley controller 40 moves the teaching trolley 20 to a stopping position N corresponding to a specific port SP and acquires teaching data. As a result, the teaching trolley 20 moves based on the control of the trolley controller 40 and automatically acquires teaching data, allowing teaching to be performed more quickly compared to manual teaching. Therefore, the time Td required for teaching the overhead transport vehicle system 1 can be shortened.

[0058] The trolley controller 40 creates a travel path that passes through multiple ports 2 via the shortest route, and has the teaching trolley 20 travel along this path. As a result, the teaching trolley 20 can efficiently perform teaching by moving through multiple specific ports SP via the shortest route.

[0059] The determination unit 35 performs positional misalignment determination based on the amount of deviation ΔP between the position P0 of the mark M indicated by the pre-stored reference image I0 and the position P1 of the mark M in the captured image I1 acquired from the imaging device 33. As a result, for example, the determination unit 35 performs positional misalignment determination by comparing the actual amount of deviation on port 2 calculated based on the deviation amount ΔP of the mark M with a predetermined distance, so the setting of the predetermined distance in the determination unit 35 can be changed relatively easily. That is, for example, if the determination trolley 30 has a retroreflective laser sensor and performs positional misalignment determination based on the presence or absence of retroreflective light from a reflector provided on port 2, changing the predetermined distance would require replacing the reflector and changing the size of the reflector, but replacing the reflectors on all ports 2 would take a relatively long time. On the other hand, in this embodiment, the predetermined distance can be changed relatively easily by changing the setting of the determination unit 35.

[0060] The predetermined distance is set to be smaller than the allowable displacement amount during transfer for each port 2. This prevents the actual displacement amount from exceeding the allowable displacement amount during transfer, even if, for example, measurement errors in positional displacement determination cause the actual displacement amount on port 2 calculated based on the displacement amount ΔP to be greater than or equal to the predetermined distance, resulting in a determination of no positional displacement.

[0061] Figure 6 is a block diagram of the modified overhead transport system 1A. Figure 7 is a side view showing the judgment trolley 30A of the modified overhead transport system 1A. As shown in Figures 6 and 7, the modified overhead transport system 1A differs from the overhead transport system 1 according to the embodiment in that the judgment trolley 30A does not have an imaging device 33 but has a laser sensor 33A (detection unit), and that the port 2 does not have a mark M but has a reflector 4 provided on the upper surface 2b of the port 2. Note that in Figure 7, the positioning pin 2a of the port 2 is omitted.

[0062] The laser sensor 33A is a retroreflective sensor that emits (projects) a laser beam L1 in a vertical direction downward and detects the retroreflective light L2 of the laser beam L1 from the reflector 4.

[0063] The reflector 4 is a reflector with a reflection range R of a predetermined distance. Specifically, as shown in Figure 8, the reflector 4 has a square reflection range R where the length of each side D is equal to the predetermined distance when viewed from above the port 2. The reflector 4 is positioned such that, for example, during the previous teaching session, the laser beam L1 is incident on the center of the reflection range R when viewed from above. The reflector 4 reflects the incident laser beam L1 and emits the retrograde light L2 upwards. Specifically, if the amount of deviation of the laser beam L1 from the center of the reflector 4 is less than half of the predetermined distance, the reflector 4 emits the retrograde light L2 upwards, and if the amount of deviation is half or more of the predetermined distance, the reflector 4 does not emit the retrograde light L2.

[0064] In the modified overhead transport vehicle system 1A, the determination unit 35A determines the positional misalignment based on the presence or absence of the retrograde light L2 (Figure 6). Specifically, the determination unit 35A determines that there is no positional misalignment (re-teaching is "not required") when the laser beam L1 is incident on the reflection range R of the reflector 4 and the laser sensor 33A detects the retrograde light L2 (Figure 8(a)). On the other hand, the determination unit 35A determines that there is a positional misalignment (re-teaching is "required") when the laser beam L1 is not incident on the reflection range R of the reflector 4 and the laser sensor 33A does not detect the retrograde light L2 (Figure 8(b)).

[0065] Even with the modified overhead transport vehicle system 1A, the time required for teaching can be shortened, similar to the overhead transport vehicle system 1 according to the embodiment. Furthermore, in the modified overhead transport vehicle system 1A, the determination unit 35A performs positional displacement determination based on the presence or absence of retrograde light. With this configuration, positional displacement determination can be performed more easily compared to positional displacement determination using the imaging device 33.

[0066] While embodiments and modifications have been described above, one aspect of this disclosure is not limited to the embodiments and modifications described above.

[0067] In the above embodiment, the trolley controller 40 outputs a specific port SP based on the determination result V output from the output unit 36, and then performs reteaching for the specific port SP. However, the trolley controller 40 does not need to perform reteaching. In this case, the operator may perform manual or semi-automatic teaching for the specific port SP based on the specific port SP output from the trolley controller 40.

[0068] Here, manual teaching refers to the process where a person manually controls each function of the teaching cart 20 using a remote controller or the like to perform teaching. Specifically, the operator uses a remote controller or the like to have the teaching unit TU, which does not have a sensor, grip the teaching cart 20, and acquires teaching data for the port 2 to be measured (in this example, a specific port SP).

[0069] Furthermore, semi-automatic teaching differs from the auto-teaching of the embodiment in that the destination of the teaching trolley 20 is set manually. In other words, in the auto-teaching of the embodiment, the trolley controller 40 automatically creates the travel path of the teaching trolley 20 and sets the destination of the teaching trolley 20, but in semi-automatic teaching, the operator manually sets the destination of the teaching trolley 20.

[0070] In the above embodiment, the trolley controller 40 created a travel path for the determination trolley 30 that passed through multiple specific ports SP via the shortest path when determining the misalignment. However, the trolley controller 40 does not necessarily have to create a travel path that passes through multiple specific ports SP via the shortest path. For example, when determining the misalignment while the transport vehicle 10 is in motion during periodic maintenance, the trolley controller 40 may create a travel path for the determination trolley 30 that prioritizes the movement of the transport vehicle 10.

[0071] For example, when performing positional misalignment detection (inspection) on multiple consecutive ports 2 provided in a buffer, the travel rail 3 provided above these ports 2 may be occupied by the detection trolley 30, potentially causing delays in the transport vehicle 10 (following vehicle) traveling along this travel rail 3 to reach its target position. In such cases, after performing positional misalignment detection on one port 2, the detection trolley 30 may leave the buffer, travel around the travel rail 3, and then proceed to the next port 2. The trolley controller 40 may also create such a travel path for the detection trolley 30. In this case, congestion of the transport vehicle 10 that may occur due to the detection trolley 30 can be suppressed. That is, when performing normal transport and inspection (positional misalignment detection) simultaneously, the travel of the transport vehicle 10 involved in normal transport may be prioritized over the travel of the detection trolley 30 to avoid congestion. Similarly, when performing reteaching, the trolley controller 40 may also create a travel path for the teaching trolley 20 that prioritizes the travel of the transport vehicle 10.

[0072] In the above embodiment, the determination unit 35 had previously acquired the position P0 of the mark M in the reference image I0 acquired during the previous teaching operation as a predetermined position. However, the determination unit 35 may also acquire the position P0 from a reference such as the design value of the overhead transport system 1. In this case, the position deviation determination process by the determination trolley 30 may be performed when the overhead transport system 1 is first operated. In this case, the trolley controller 40 performs teaching using the teaching trolley 20 only for specific ports SP that have been determined to have a position deviation from the design data. Even in this case, the time required for teaching the overhead transport system 1 can be shortened.

[0073] The "default position" is not necessarily limited to a single point, such as the position of mark M on port 2. The default position may be multiple points, such as the vertices of a polygon on port 2, or it may be the position of a planar shape with a certain area. The default position may also be a positioning pin 2a installed on port 2 to fix the position of an item. The outer shape of port 2 itself (such as the outer shape of the top surface in a plan view) may also be used. Any type of position that can be uniquely determined based on the travel stop position can be adopted as the default position.

[0074] In the above embodiment, the output unit 36 ​​output the judgment result V to the trolley controller 40. However, the output unit 36 ​​does not have to output the judgment result V to the trolley controller 40; the operator may extract the judgment result V from the judgment trolley 30 and input it to the trolley controller 40.

[0075] In the above embodiment, the determination cart 30 may be a transport vehicle 10 that holds a determination unit which includes some of the functions of the determination cart 30 (for example, an imaging device 33, a storage unit 34, a determination unit 35, and an output unit 36). In this case, the determination cart 30 does not need to lower the determination unit to the port 2, and the mark M may be imaged from above the port 2 with the determination unit as close as possible to the determination cart 30 in the vertical direction.

[0076] In the above embodiment, the determination trolley 30 performed positional deviation detection on all ports 2, but the determination trolley 30 may perform positional deviation detection on only some of the ports 2. For example, the trolley controller 40 may divide the running rail 3 into several areas, determine the priority area where it wants to restart the operation of the overhead transport system 1 first, and perform positional deviation detection and re-teaching on the ports 2 in the priority area first. Furthermore, it is not necessary to perform positional deviation detection on all ports 2 in each area, and positional deviation detection may be performed only on the ports 2 that represent each area.

[0077] In the above embodiment, the determination unit 35 performed positional deviation determination only in the horizontal direction (X direction and Y direction), but the determination unit 35 may also perform positional deviation determination in the vertical direction (Z direction) and rotational amount in addition to the horizontal direction. Here, the rotational amount may be, for example, the rotation angle of the determination trolley 30 around the Z direction with respect to the port 2. Furthermore, the determination unit 35 may determine that there is a positional deviation when any one of the values ​​set for each direction and rotational amount exceeds the predetermined distance (a predetermined threshold for the rotational amount). In this case, for example, the determination trolley 30 may have a distance sensor that acquires the distance to the port 2.

[0078] In the above embodiment, there were multiple specific ports SP, but there may be only one. Also, if there is no port 2 that is determined to have a misalignment, the trolley controller 40 may output a message indicating that there is no port 2 corresponding to the specific port SP.

[0079] In the above embodiment, the trolley controller 40 does not necessarily have to output only specific ports SP, and may output all of the judgment results V output by the output unit 36. Furthermore, the trolley controller 40 may use the displacement amount ΔP included in the judgment result V to correct the teaching data for ports 2 that are determined to have no positional misalignment.

[0080] In the above embodiment, the storage unit 34 stored the reference image I0, but the storage unit 34 does not have to store the reference image I0. For example, it may only store the coordinate data of the position P0 of the mark M on the reference image I0. Even in this case, the determination unit 35 can perform a positional misalignment determination based on the amount of misalignment ΔP between the previously stored position P0 of the mark M and the position P1 of the mark M in the captured image I1.

[0081] The calculation results of the displacement amount can also be used for purposes other than determining the positional displacement of individual ports (transfer destinations). For example, the displacement amount data may be stored or accumulated, and the positional displacement of the running rail 3 itself may be estimated based on this displacement amount data, the time data corresponding to each displacement amount data, and the arrangement of ports (transfer destinations). The trolley controller 40 may also output the estimation result to prompt maintenance of the running rail 3.

[0082] 1, 1A... Overhead transport system, 2... Port (transfer destination), 3... Running rail (track), 4... Reflector, 20... Teaching cart, 30, 30A... Judgment cart, 33... Imaging device (detection unit), 33A... Laser sensor (detection unit), 35, 35A... Judgment unit, 36... Output unit, 40... Cart controller, F... Item, I0... Reference image, I1... Captured image, L2... Retrograde light, M... Mark, N... Travel stop position, P0... Position, P1... Position, R... Reflection range, SP... Specific port (specific transfer destination).

Claims

1. An overhead transport vehicle system comprising: a plurality of transfer destinations; a track provided above the plurality of transfer destinations; a transport vehicle that travels along the track and transfers items to the plurality of transfer destinations; a teaching trolley that travels along the track and acquires teaching data used when the transport vehicle transfers items to the plurality of transfer destinations by lowering a teaching unit to the transfer destination at a travel stop position corresponding to each of the plurality of transfer destinations; a determination trolley that travels along the track and acquires data used for position deviation determination at the travel stop position; a determination unit that performs position deviation determination to determine whether the position indicated by the data acquired by the detection unit is deviated by a predetermined distance or more from the position indicated by pre-stored predetermined position data; and an output unit that outputs the determination result of the determination unit; and a trolley controller that controls the transport vehicle, the teaching trolley and the determination trolley, wherein the trolley controller outputs the transfer destinations that have been determined to have a position deviation as specific transfer destinations based on the determination result output from the output unit.

2. The overhead transport vehicle system according to claim 1, wherein the trolley controller causes the teaching trolley to travel to the travel stop position corresponding to the specified transfer destination and acquires the teaching data.

3. The overhead transport vehicle system according to claim 1 or 2, wherein the trolley controller creates a travel path that passes through a plurality of specified transfer destinations via the shortest route, and causes the teaching trolley to travel along the travel path.

4. The overhead transport vehicle system according to claim 1 or 2, wherein the transfer destination has a mark indicating a reference position, the detection unit is an imaging device that captures an image including the mark, the predetermined position data is data indicating the position of the mark, and the determination unit performs the position deviation determination based on the amount of deviation between the position of the mark indicated by the predetermined position data and the position of the mark in the image captured from the imaging device.

5. The overhead transport vehicle system according to claim 1 or 2, wherein the transfer destination has a reflector whose reflection range is the predetermined distance, the detection unit is a retroreflective sensor that detects retroreflective light from the reflector, and the determination unit performs the positional displacement determination based on the presence or absence of the retroreflective light.

6. The overhead transport vehicle system according to claim 1 or 2, wherein each of the transfer destinations has an allowable amount of displacement of the article during transfer, and the predetermined distance used for determining the positional displacement in the determination trolley is set to be smaller than the allowable amount of displacement during transfer.

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