Carrier vehicle

Abstract

To desirably realize a carrier vehicle that can be properly stopped even if a problem occurs in power supplying.SOLUTION: A carrier vehicle for transporting goods comprises: a travel device having a travel drive unit; a control device that controls the travel device; and a power supply unit that receives electric power from an external source and supplies the electric power to at least the travel device and the control device. While a voltage supplied from the power supply unit to the travel device is defined as a target voltage V1, and a lower limit voltage required to operate the travel device is defined as a required lower limit voltage Vs1, the control device monitors a target voltage V1 and executes a deceleration stop process that reduces the travel speed of the carrier vehicle and stops the travel of the carrier vehicle when the target voltage becomes equal to or lower than a determination threshold value Vt1 that is set lower than a voltage during normal operation of the power supply unit and higher than the required lower limit voltage Vs1 while the carrier vehicle is traveling.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a transport vehicle for transporting articles. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open No. 2022-003858 (Patent Document 1) discloses a technology related to a transport vehicle. In the following description of the background art, the reference numerals in parentheses refer to those in Patent Document 1.

[0003] The conveying facility (100) of Patent Document 1 includes a traveling rail (2) arranged along a traveling path (1), and a conveying vehicle (article conveying vehicle 3) that is guided by the traveling rail (2) and travels along the traveling path (1). The conveying facility (100) also includes a power supply line (11) arranged along the traveling path (1) and a plurality of article handling units (P). The conveying vehicle receives driving power from the power supply line (11) in a non-contact manner, thereby traveling along the traveling path (1) and conveying articles to the article handling units (P). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-003858 Summary of the Invention [Problem to be solved by the invention]

[0005] In a conveying facility such as that described in Patent Document 1, when power is no longer supplied to the power supply line due to, for example, a power outage or a failure of the power supply unit, the conveying vehicle may suddenly stop on the traveling rail due to a lack of power required for traveling. When the conveying vehicle suddenly stops in this way, the conveying vehicle itself is likely to be subjected to a large load, and the goods being conveyed are likely to be subjected to a large acceleration. This may cause problems such as a shortened lifespan of the conveying vehicle and a high likelihood of damage to the goods being conveyed.

[0006] Therefore, it is desirable to realize a transport vehicle that can be stopped appropriately even if a problem occurs in the power supply. [Means for solving the problem]

[0007] The transport vehicle according to the present disclosure is a transport vehicle that transports an article, A traveling device having a traveling drive unit, a control device for controlling the traveling device, and a power supply unit for receiving power from an external source and supplying power to at least the traveling device and the control device, The voltage supplied from the power supply unit to the traveling device is defined as a target voltage, and the lower limit voltage required to operate the traveling device is defined as a required lower limit voltage, The control device monitors the target voltage, and when, while the transport vehicle is traveling, the target voltage falls below a judgment threshold value that is set to a value lower than the voltage during normal operation of the power supply unit and higher than the required lower limit voltage, the control device executes a deceleration and stop process that reduces the traveling speed of the transport vehicle and stops the transport vehicle from traveling.

[0008] According to this configuration, even if the voltage (target voltage) supplied to the traveling device drops below the required lower limit voltage due to a power supply failure caused by a power outage, a power supply unit failure, etc., the transportation vehicle can start decelerating when the voltage reaches the determination threshold value. Therefore, it is possible to prevent the transportation vehicle from suddenly stopping due to the traveling device becoming inoperable as a result of the target voltage falling below the required lower limit voltage. In this way, sudden stops of the transport vehicle can be avoided, and adverse effects such as large acceleration acting on the goods being transported can be mitigated.

[0009] Further features and advantages of the transport vehicle will become apparent from the following description of exemplary, non-limiting embodiments, which are given with reference to the drawings. [Brief description of the drawings]

[0010] [Figure 1] FIG. 13 is a front view showing a transfer operation of the transport vehicle; [Diagram 2] FIG. 2 is a plan view showing a schematic diagram of a travel path of the transport vehicle and a processing device; [Diagram 3] Side view of the transport vehicle [Figure 4] Control Block Diagram [Diagram 5] FIG. 13 is a diagram showing a stopping pattern of a transport vehicle in a deceleration and stopping process. [Figure 6] Control Flow Diagram [Figure 7] Control Flow Diagram [Figure 8] Control Flow Diagram [Figure 9] Control flow diagram of another embodiment DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An embodiment of the transport vehicle will be described below as an example applied to a transport facility.

[0012] 1 and 2, the transport facility 100 includes a transport vehicle 1 that travels along a travel path 5, a travel rail 4 that guides the transport vehicle 1, a plurality of processing devices 7, and a host control system C that performs overall control of the transport facility 100. The travel rail 4 is disposed along the travel path 5. The plurality of processing devices 7 are also disposed along the travel path 5.

[0013] In this embodiment, the transport vehicle 1 transports an article W. Specifically, the transport vehicle 1 travels along a travel path 5 to transfer the article W to a plurality of processing devices 7. In this embodiment, the travel path 5 is set to follow the ceiling of the transport facility 100. For this reason, the travel rail 4 is arranged in a state of being suspended and supported from the ceiling. That is, the transport vehicle 1 is a ceiling transport vehicle that travels along the travel path 5 set along the ceiling. In this example, a pair of travel rails 4 is provided. Then, a plurality of transport vehicles 1 travel on a pair of left and right travel rails 4 (FIG. 1). Note that the transport vehicle 1 is not limited to a ceiling transport vehicle. The transport vehicle 1 may be, for example, an unmanned transport vehicle that travels autonomously on a floor surface or the like.

[0014] The processing device 7 is a device that performs a predetermined process on the object W. Each of the multiple processing devices 7 is provided below the traveling rail 4. Here, each processing device 7 is provided on the floor surface of the conveyance facility 100. In this example, the processing device 7 includes a transfer target location 7a to which the object W is transferred and a processing main body 7b where processing is performed. Here, the transfer target location 7a is a delivery port. That is, the transfer target location 7a is a port for delivering the object W to and from the conveyance vehicle 1. In this embodiment, the object W can be, for example, a container that contains a semiconductor wafer used in the manufacture of a semiconductor device or a reticle for processing. That is, the object W can be, for example, a FOUP that contains a semiconductor wafer, a reticle pod that contains a reticle, etc. In the processing main body 7b, processing is performed on the contents contained in such an object W.

[0015] The upper control system C transmits a transport command to each of the multiple transport vehicles 1 traveling on the travel route 5. Each transport vehicle 1 transports an article W between the multiple processing devices 7 based on the transport command from the upper control system C. The upper control system C includes an upper communication device 101. The upper communication device 101 is configured to communicate with a communication device 9 of the transport vehicle 1, which will be described later.

[0016] 1 to 4, the transport vehicle 1 includes a traveling device 2 having a travel drive unit 21, a control device 10 that controls the traveling device 2, and a power supply unit 3 that receives power from an external source and supplies power to at least the traveling device 2 and the control device 10. In this embodiment, the transport vehicle 1 further includes a holding device 62 that holds an article W, a lifting device 72 that lifts and lowers the holding device 62, a sliding device 82 that moves the holding device 62 in and out in a specific entry / exit direction Y along the horizontal direction, and a communication device 9.

[0017] In the following description, the direction along the travel path 5 is defined as a travel direction X, and the direction perpendicular to the travel direction X when viewed from the up-down direction (rail width direction) is defined as an exit / entrance direction Y.

[0018] The traveling device 2 includes, as a traveling drive unit 21, traveling wheels 22 that roll on the traveling rail 4, and a traveling motor M (FIG. 3) that drives the traveling wheels 22. In this example, as shown in FIGS. 1 and 3, the transport vehicle 1 further includes a vehicle body 11, a storage unit 17 that stores an article W, and a cover 16 that covers the storage unit 17. Here, a plurality of traveling wheels 22 are provided on the vehicle body 11. The traveling motor M drives at least one of the plurality of traveling wheels 22 to provide a propulsive force for the vehicle body 11 to travel along the traveling direction X. Note that the traveling motor M may be a linear motor, and in that case, the traveling wheels 22 may not necessarily be provided. In this example, the vehicle body 11 is disposed above the traveling rail 4.

[0019] The storage section 17 is disposed below the traveling rail 4. When the transport vehicle 1 transports the item W toward the transfer target location 7a, the vehicle body 11 travels with the item W stored in the storage section 17. The cover 16 is suspended and supported by the vehicle body 11. The cover 16 covers the upper side and both sides in the traveling direction X of the storage section 17. In the illustrated example, the cover 16 is not disposed on either outer side of the storage section 17 in the exit / entrance direction Y, and the both outer sides are open.

[0020] The lifting device 72 is configured to lift and lower the holding device 62 between a height corresponding to the transfer target location 7a and a height corresponding to the storage section 17. As shown in FIG. 3, the lifting device 72 is disposed in the storage section 17. In this example, the lifting device 72 includes a drum 73, a belt 74 wound around the drum 73 and connected to the holding device 62 at its tip, and a lifting motor (not shown). The drum 73 is rotated by driving the lifting motor to wind or unwind the belt 74, thereby lifting and lowering the holding device 62 and the article W held by the holding device 62. The vehicle body 11 stops at a position corresponding to the transfer target location 7a, and the lifting device 72 lifts and lowers the article W held by the holding device 62, making it possible to transfer the article W between the transfer target location 7a (here, the delivery port).

[0021] The slide device 82 includes a slide body 83 that moves along the entrance / retraction direction Y (here, the rail width direction) relative to the storage section 17, and a slide motor (not shown) that slides and moves the slide body 83 in the entrance / retraction direction Y. By moving the slide body 83 by driving the slide motor, the lifting device 72, the holding device 62, and the article W held by the holding device 62 can be moved along the entrance / retraction direction Y. As shown in FIG. 2, when the transfer target location 7a of the processing device 7 is disposed at a position away from the travel path 5 in the entrance / retraction direction Y, the slide device 82 transfers the article W between the transfer target location 7a and the transfer target location 7a by sliding the slide body 83. In this example, the slide device 82 is stored in the storage section 17, and the slide body 83 is moved in and out of the storage section 17 in the entrance / retraction direction Y as necessary.

[0022] The holding device 62 includes a pair of gripping claws and a gripping motor that moves the pair of gripping claws closer to and farther apart. The holding device 62 is configured to switch between a gripping state in which the article W is gripped and a grip release state in which the grip of the article W is released by moving the pair of gripping claws closer to and farther apart.

[0023] In this example, as shown in FIG. 3, the transport vehicle 1 is equipped with a detection device 15. The detection device 15 detects a plurality of detectable objects 43 (FIG. 2) installed along the travel path 5. The detectable objects 43 hold position information (address information) indicating the position at which the detectable objects 43 are installed, and the detection device 15 is configured to read the position information. The detectable objects 43 are installed on branching and merging paths in the travel path 5, as well as at positions corresponding to the transfer target locations 7a. Here, the detectable objects 43 are barcode labels and are provided on the underside of the travel rail 4. The detection device 15 is also provided on the upper surface of the cover 16, and is configured to read the barcode labels facing the transport vehicle 1 while the transport vehicle 1 is traveling.

[0024] 4, the communication device 9 is configured to communicate with a host control system C that controls multiple transport vehicles 1. Examples of functions of the communication device 9 include receiving transport commands from the host control system C and transmitting position information, speed information, and the like of the transport vehicles 1 to the host control system C.

[0025] The power supply unit 3 includes a power receiving device 32 (FIG. 4) that receives power from a power supply line (not shown) arranged along the travel path 5. In this example, the power receiving device 32 is supplied with power from the power supply line in a non-contact manner. The power receiving device 32 includes a pickup coil (not shown) and a power receiving unit (not shown) formed on a wiring board inside the transport vehicle 1. The power receiving unit is electrically connected to the pickup coil, and an electrical load whose power consumption varies is electrically connected to the power receiving unit. The AC current and AC voltage induced in the pickup coil are converted to DC current and DC voltage by a rectifier circuit such as a full-wave rectifier circuit and a power receiving circuit including a smoothing capacitor in the power receiving unit, and are supplied to the electrical load. Examples of this electrical load include the traveling device 2, the holding device 62, the lifting device 72, and the sliding device 82 as described above.

[0026] In this embodiment, as shown in FIG. 4, the power supply unit 3 includes a power storage device 31 that temporarily stores power. The power storage device 31 is configured to supply the voltage of the power storage device 31 to the traveling device 2. Here, the power storage device 31 is configured to respond to an instantaneous voltage drop in the transport vehicle 1. That is, when the voltage supply to the traveling device 2 is instantaneously dropped due to a power supply failure caused by a power outage or a failure of the power supply unit 3, the power storage device 31 supplies a voltage to the traveling device 2. In this embodiment, the power storage device 31 is configured to be able to supply power not only to the traveling device 2 but also to electrical loads such as the holding device 62, the lifting device 72, and the sliding device 82. The power storage device 31 can be a capacitor provided on the board of the power supply unit 3. Also, a small battery can be provided as the power storage device 31.

[0027] As shown in FIG. 4, the control device 10 controls the traveling device 2, the lifting device 72, the holding device 62, the sliding device 82, the detection device 15, and the power supply unit 3. The control device 10 is configured to be able to communicate with a higher-level control system C. The control device 10 and the higher-level control system C include, for example, a processor such as a microcomputer, and peripheral circuits such as a memory. Each function is realized by cooperation between these hardware and a program executed on a processor such as a computer. In this embodiment, the control device 10 is configured to control the traveling device 2 based on a command from the higher-level control system C. The control device 10 also controls the holding device 62 and the sliding device 82 based on a command from the higher-level control system C. The control device 10 may be configured to control only the traveling device 2.

[0028] In the following, the voltage supplied from the power supply unit 3 to the traveling device 2 is referred to as a first target voltage V1, and the lowest voltage required to operate the traveling device 2 is referred to as a first necessary lower limit voltage Vs1. Furthermore, the voltage supplied from the power supply unit 3 to the lifting device 72 is referred to as a second target voltage V2, and the lowest voltage required to operate the lifting device 72 is referred to as a second necessary lower limit voltage Vs2. Similarly, the voltage supplied from the power supply unit 3 to the sliding device 82 is referred to as a third target voltage V3, and the lowest voltage required to operate the sliding device 82 is referred to as a third necessary lower limit voltage Vs3. Here, the first necessary lower limit voltage Vs1 corresponds to the "necessary lower limit voltage."

[0029] As shown in FIG. 5, the control device 10 is configured to monitor a first object voltage V1. The control device 10 is further configured to monitor a second object voltage V2 and a third object voltage V3. In this example, the control device 10 monitors the voltage supplied to a driver (such as a servo driver, the same applies below) of the traveling motor M of the traveling device 2 as the first object voltage V1. The control device 10 also monitors the voltage supplied to a driver of the lifting motor as the second object voltage V2. The control device 10 also monitors the voltage supplied to a driver of the sliding motor as the third object voltage V3. The control device 10 may also monitor the voltage supplied to the motor body of each of the motors. Here, the first object voltage V1 corresponds to the "object voltage".

[0030] In this embodiment, the control device 10 executes normal transport control. The normal transport control is a control for transporting the item W between a predetermined transfer target location 7a based on a transport command received from the upper control system C. Here, as an example of the normal transport control, the control for transporting the item W to a predetermined transfer target location 7a will be described. When the control device 10 receives a transport command, it controls the traveling device 2 to move the transport vehicle 1 to a position (here, a position on the traveling rail 4) corresponding to the transfer target location 7a of the transport destination. When the transport vehicle 1 approaches the position, the control device 10 controls the traveling device 2 to decelerate the transport vehicle 1 so that it can stop at an appropriate stop position. The control device 10 may decelerate the transport vehicle 1 when the detection device 15 detects the detectable object 43 arranged in front of the transfer target location 7a of the transport destination. When the transport vehicle 1 stops, the control device 10 transmits the stop position to the upper control system C. In this example, the control device 10 calculates the stop position based on the position information obtained from the detected object 43 and the amount of movement of the transportation vehicle 1 from the detected object 43 to the stop position detected by the encoder of the traveling motor M.

[0031] When the transfer target location 7a of the transfer destination is located directly below the traveling rail 4, the control device 10 controls the lifting device 72 to lower the holding device 62 and the article W held by the holding device 62. When the transfer target location 7a of the transfer destination is located at a position shifted in the retraction direction Y with respect to the traveling rail 4, the control device 10 controls the slide device 82 to move the holding device 62 and the article W held by the holding device 62 to directly above the transfer target location 7a. Thereafter, the control device 10 controls the lifting device 72 to lower the holding device 62 and the article W held by the holding device 62. When the article W is placed on the transfer target location 7a, the control device 10 controls the holding device 62 to release the pair of gripping claws from the gripping state.

[0032] In the normal transport process, when the transport vehicle 1 travels on the travel rail 4, a properly set specified voltage (normal voltage V0) is continuously supplied to the travel device 2. In addition, when the transport vehicle 1 is stopped on the travel rail 4 and the article W is transferred to the transfer target location 7a, the normal voltage V0 is supplied to the slide device 82 and the lifting device 72 as necessary. In the example of FIG. 5, the normal voltages V0 supplied to the travel device 2, the slide device 82, and the lifting device 72 are set to the same value. Note that the normal voltages V0 supplied to the travel device 2, the slide device 82, and the lifting device 72 may be set to different values. In addition, an upper limit and a lower limit can be set for the normal voltage V0, and the voltage value from the lower limit to the upper limit can be set as the range of the normal voltage V0.

[0033] On the other hand, when a power supply failure occurs, such as when power is not supplied to the power supply unit 3 due to a power outage or the like, the first target voltage V1, the second target voltage V2, and the third target voltage V3 become values ​​lower than the normal voltage V0 (FIG. 5). Note that factors that cause these target voltages to fall below the required lower limit voltages (first required lower limit voltage Vs1, second required lower limit voltage Vs2, third required lower limit voltage Vs3) include a power shortage for each motor (travel motor M, lift motor, slide motor) due to such a power supply failure, an error in the drivers of these motors, and the like.

[0034] As shown in Fig. 5 to Fig. 9, the control device 10 executes a first deceleration stop process, a second deceleration stop process, and a third deceleration stop process. As shown in Fig. 5 and Fig. 6, the first deceleration stop process is a process for executing a first deceleration stop process to reduce the traveling speed of the transport vehicle 1 and stop the travel of the transport vehicle 1 when the first target voltage V1 becomes equal to or lower than a first determination threshold Vt1 set to a value lower than the voltage (normal voltage V0) during normal operation of the power supply unit 3 and higher than a first necessary lower limit voltage Vs1 while the transport vehicle 1 is traveling. Here, the first deceleration stop process corresponds to the "deceleration stop process" and the first necessary lower limit voltage Vs1 corresponds to the "necessary lower limit voltage".

[0035] As shown in FIG. 5, the time required from the start to the completion of the first deceleration stop process is defined as the first required processing time Ta, and the amount of decrease per unit time of the first target voltage V1 in the case where an abnormality occurs in the power supply from the power supply unit 3 is defined as the first voltage decrease rate Ra. The first determination threshold value Vt1 is set to a value obtained by multiplying the first voltage decrease rate Ra by the first required processing time Ta and adding the result to the first required lower limit voltage Vs1. In the example of FIG. 5, the first voltage decrease rate Ra from the normal voltage V0 is constant, but is not limited to this. In this example, the difference E between the first determination threshold value Vt1 and the first required lower limit voltage Vs1 is set to be greater than the value obtained by multiplying the first voltage decrease rate Ra by the first required processing time Ta. As a result, the first determination threshold value Vt1 is greater than the value obtained by adding the value obtained by multiplying the first voltage decrease rate Ra by the first required processing time Ta to the first required lower limit voltage Vs1. In this example, the first required processing time Ta is the time from when the transporting vehicle 1 starts to decelerate to when the transporting vehicle 1 completely stops moving in the traveling direction X. The first voltage drop rate Ra corresponds to the "voltage drop rate", and the first required processing time Ta corresponds to the "required processing time".

[0036] In this embodiment, as shown in FIG. 6, the control device 10 judges whether the first object voltage V1 is greater than the first judgment threshold Vt1 (S01). When the control device 10 judges that the first object voltage V1 is equal to or less than the first judgment threshold Vt1 (S01: No), the control device 10 executes a first deceleration and stop process (S02). In this example, when the control device 10 detects that the first object voltage V1 is equal to the first judgment threshold Vt1, the control device 10 controls the traveling device 2 to decelerate the transportation vehicle 1. Then, the control device 10 controls the traveling device 2 to stop the transportation vehicle 1 before the first object voltage V1 falls below the first necessary lower limit voltage Vs1. In the example of FIG. 5, the control device 10 stops the transportation vehicle 1 at the same time as the first object voltage V1 becomes equal to the first necessary lower limit voltage Vs1. In this way, in the first deceleration and stoppage procedure, the control device 10 controls the traveling device 2 to stop the transport vehicle 1 during a period in which the first target voltage V1 is smaller than the first judgment threshold value Vt1 and is equal to or greater than the first necessary lower limit voltage Vs1. In this example, the control device 10 decelerates the transport vehicle 1 at a predetermined deceleration rate and stops the transport vehicle 1 before the first target voltage V1 falls below the first necessary lower limit voltage Vs1. In the illustrated example, the deceleration rate per unit time of the transport vehicle 1 is constant, but this is not limited to this. Here, the control device 10 may transmit the stop position of the transport vehicle 1 to the upper control system C after the first deceleration and stoppage procedure. This makes it easier for the upper control system C to estimate the accurate stop position of the transport vehicle 1 in the recovery work after the power supply failure is resolved. Therefore, the period of the recovery work can be shortened. In addition, the control device 10 may be configured not to monitor the first target voltage V1 in the first place. In that case, the control device 10 may also be configured not to execute the first deceleration and stoppage process.

[0037] As shown in Figures 5 and 7, the second deceleration stop process is a process that executes a second deceleration stop process to reduce the lifting / lowering speed of the holding device 62 by the lifting device 72 and stop the lifting / lowering of the holding device 62 when the second target voltage V2 falls below a second judgment threshold Vt2 that is set to a value lower than the voltage during normal operation of the power supply unit 3 and higher than the second required lower limit voltage Vs2 during the lifting / lowering operation of the holding device 62 by the lifting / lowering device 72.

[0038] As shown in FIG. 5, the time required from the start to the completion of the second deceleration stop process is the second required processing time Tb, and the amount of decrease per unit time of the second target voltage V2 in the event of an abnormality in the power supply from the power supply unit 3 is the second voltage decrease rate Rb. The second determination threshold Vt2 is set to a value obtained by multiplying the second voltage decrease rate Rb by the second required processing time Tb and adding the result to the second required lower limit voltage Vs2. In the example of FIG. 5, the second voltage decrease rate Rb from the normal voltage V0 is constant, but is not limited to this. In this example, the difference F between the second determination threshold Vt2 and the second required lower limit voltage Vs2 is set to be greater than the value obtained by multiplying the second voltage decrease rate Rb by the second required processing time Tb. As a result, the second determination threshold Vt2 is greater than the value obtained by adding the value obtained by multiplying the second voltage decrease rate Rb by the second required processing time Tb to the second required lower limit voltage Vs2. In this example, the second required process time Tb is set to the time from when the holding device 62 starts to decelerate (reduce the lifting speed) until the holding device 62 is completely stopped.

[0039] In this embodiment, as shown in FIG. 7, the control device 10 judges whether the second object voltage V2 is greater than the second judgment threshold Vt2 (S11). When the control device 10 judges that the second object voltage V2 is equal to or less than the second judgment threshold Vt2 (S11: No), the control device 10 executes the second deceleration stop process (S12). In this example, when the control device 10 detects that the second object voltage V2 is equal to the second judgment threshold Vt2, the control device 10 controls the lifting device 72 to decelerate the holding device 62. Then, the control device 10 controls the lifting device 72 to stop the lifting of the holding device 62 before the second object voltage V2 falls below the second necessary lower limit voltage Vs2. In the example of FIG. 5, the control device 10 stops the holding device 62 at the same time as the second object voltage V2 becomes equal to the second necessary lower limit voltage Vs2. In this way, in the second deceleration stop procedure, the control device 10 controls the lifting device 72 to stop the holding device 62 during the period when the second target voltage V2 is smaller than the second judgment threshold Vt2 and equal to or greater than the second necessary lower limit voltage Vs2. Here, the control device 10 may transmit the stop position of the holding device 62 in the vertical direction (lifting direction) to the upper control system C after the second deceleration stop procedure. This makes it easier for the upper control system C to estimate the accurate stop position of the holding device 62 during recovery work after the power supply failure is resolved. Therefore, the period of the recovery work can be shortened. Note that the control device 10 can estimate the vertical position of the holding device 62, for example, by using an encoder or the like mounted on the lifting motor.

[0040] As shown in Figures 5 and 8, the third deceleration and stop control is a process that executes a third deceleration and stop process to slow down the extension / retraction speed of the holding device 62 by the sliding device 82 and stop the extension / retraction of the holding device 62 when the third target voltage V3 becomes equal to or lower than the third judgment threshold Vt3 which is set to a value lower than the voltage (normal voltage V0) during normal operation of the power supply unit 3 and higher than the third required lower limit voltage Vs3 during the extension / retraction operation of the holding device 62 by the sliding device 82.

[0041] As shown in FIG. 5, the time required from the start to the completion of the third deceleration stop process is the third required process time Tc, and the amount of decrease per unit time of the third target voltage V3 in the event of an abnormality in the power supply from the power supply unit 3 is the third voltage decrease rate Rc. The third determination threshold Vt3 is set to a value obtained by multiplying the third voltage decrease rate Rc by the third required process time Tc and adding the result to the third required lower limit voltage Vs3. In the example of FIG. 5, the third voltage decrease rate Rc from the normal voltage V0 is constant, but is not limited to this. In this example, the difference G between the third determination threshold Vt3 and the third required lower limit voltage Vs3 is set to be greater than the value obtained by multiplying the third voltage decrease rate Rc by the third required process time Tc. As a result, the third determination threshold Vt3 is greater than the value obtained by adding the value obtained by multiplying the third voltage decrease rate Rc by the third required process time Tc to the third required lower limit voltage Vs3. In this example, the third required processing time Tc is the time from when the holding device 62 starts to decelerate (reduce the retraction speed) to when the movement of the holding device 62 in the retraction direction Y is completely stopped.

[0042] In this embodiment, as shown in FIG. 8, the control device 10 judges whether the third object voltage V3 is greater than the third judgment threshold Vt3 (S21). When the control device 10 judges that the third object voltage V3 is equal to or less than the third judgment threshold Vt3 (S21: No), the control device 10 executes a third deceleration stop process (S22). In this example, when the control device 10 detects that the third object voltage V3 has decreased to the same value as the third judgment threshold Vt3, the control device 10 controls the slide device 82 to decelerate the holding device 62. Then, the control device 10 controls the slide device 82 to stop the sliding movement of the holding device 62 before the third object voltage V3 falls below the third necessary lower limit voltage Vs3. In the example of FIG. 5, the control device 10 stops the holding device 62 at the same time that the third object voltage V3 becomes equal to the third necessary lower limit voltage Vs3. In this way, in the third deceleration stop procedure, the control device 10 controls the slide device 82 to stop the holding device 62 during the period when the third target voltage V3 is smaller than the third judgment threshold Vt3 and equal to or greater than the third necessary lower limit voltage Vs3. Here, the control device 10 may transmit the stop position of the holding device 62 in the moving-out direction Y to the upper control system C after the third deceleration stop procedure. This makes it easier for the upper control system C to estimate the accurate stop position of the holding device 62 in the recovery work after the power supply failure is eliminated. Therefore, the period of the recovery work can be shortened. The control device 10 can estimate the position of the holding device 62 in the moving-out direction Y, for example, by an encoder mounted on the slide motor. In this example, as shown in FIG. 5, the first judgment threshold Vt1, the second judgment threshold Vt2, and the third judgment threshold Vt3 are set to the same value, but these values ​​may be different from each other.

[0043] As shown in FIG. 5, when the first deceleration stop process, the second deceleration stop process, and the third deceleration stop process are not executed, the travel of the transport vehicle 1 suddenly stops when the first target voltage V1 becomes equal to or lower than the first necessary lower limit voltage Vs1. Similarly, when the second target voltage V2 becomes equal to or lower than the second necessary lower limit voltage Vs2, the lifting and lowering movement of the holding device 62 suddenly stops. Also, when the third target voltage V3 becomes equal to or lower than the third necessary lower limit voltage Vs3, the sliding movement of the holding device 62 suddenly stops. In the example of FIG. 5, when the normal voltage V0 is supplied, the travel speed of the transport vehicle 1, the lifting and lowering speed of the holding device 62, and the entrance and exit speed are each set to a constant speed S1. After that, when each target voltage decreases to the necessary lower limit voltage (time T2), the travel speed of the transport vehicle 1, the lifting and lowering speed of the holding device 62, and the entrance and exit speed each decrease at a constant rate and then become 0 (time T3). 5 merely shows the travel speed of the transport vehicle 1, the elevation speed of the holding device 62, and the changes in the entrance and exit speeds in a schematic manner. Therefore, the speed S1 does not indicate that the travel speed of the transport vehicle 1, the elevation speed of the holding device 62, and the entrance and exit speeds are all the same.

[0044] On the other hand, in the example of Fig. 5, when the first deceleration stop process, the second deceleration stop process, and the third deceleration stop process are executed, when the first target voltage V1 becomes equal to or less than the first judgment threshold Vt1 (time T1), the control device 10 controls the transportation vehicle 1 to decelerate, and when the first target voltage V1 becomes equal to the first necessary lower limit voltage Vs1, the control device 10 stops the transportation vehicle 1 (time T2). Similarly, when the second target voltage V2 becomes equal to or less than the second judgment threshold Vt2 (time T1), the control device 10 controls the lifting and lowering movement of the holding device 62 to decelerate, and when the second target voltage V2 becomes equal to the second necessary lower limit voltage Vs2, the control device 10 stops the lifting and lowering movement of the holding device 62 (time T2). Also, when the third target voltage V3 becomes equal to or less than the third judgment threshold Vt3 (time T1), the control device 10 controls the sliding movement of the holding device 62 to decelerate, and when the third target voltage V3 becomes equal to the third necessary lower limit voltage Vs3, the control device 10 stops the sliding movement of the holding device 62 (time T2). In this way, by executing the first deceleration stop process, the second deceleration stop process, and the third deceleration stop process, the rates of decrease in the travel speed of the transport vehicle 1, the lifting / lowering speed of the holding device 62, and the exit / return speed are more gradual than when the first deceleration stop process, the second deceleration stop process, and the third deceleration stop process are not executed. Also, in the example of Fig. 5, by executing the first deceleration stop process, the second deceleration stop process, and the third deceleration stop process, the stop of the travel of the transport vehicle 1, the stop of the lifting / lowering movement of the holding device 62, and the stop of the sliding movement are completed earlier (time T2) than when these processes are not executed.

[0045] Other embodiments (1) In the above embodiment, the transport vehicle 1 transports the items W to a plurality of processing devices 7, but the present invention is not limited to this. The transport vehicle 1 may also be configured to transport the items W to, for example, a storage shelf or the like that stores the items W.

[0046] (2) In the above embodiment, the execution of the first deceleration stop process, the second deceleration stop process, and the third deceleration stop process causes the travel of the transport vehicle 1, the lifting and lowering movement of the holding device 62, and the sliding movement to be stopped earlier than when these processes are not executed. However, the present invention is not limited to this. For example, the completion times of the stop of the travel of the transport vehicle 1, the lifting and lowering movement of the holding device 62, and the sliding movement may be the same when the first deceleration stop process, the second deceleration stop process, and the third deceleration stop process are executed and when they are not executed.

[0047] (3) In the above embodiment, the first determination threshold Vt1 is set to a value equal to or greater than the value obtained by multiplying the first voltage drop rate Ra by the first required processing time Ta and adding the result to the first required lower limit voltage Vs1. However, the present invention is not limited to this. The first determination threshold Vt1 can be set to any value as long as it is greater than the first required lower limit voltage Vs1 and less than the normal voltage V0.

[0048] (4) In the above embodiment, when the first target voltage V1 becomes equal to or less than the first judgment threshold Vt1, the control device 10 controls the traveling device 2 to decelerate and stop the transport vehicle 1 at a constant speed reduction rate as the first deceleration and stop process, and does not set a target stop position of the transport vehicle 1. However, the present invention is not limited to this. In the deceleration and stop process, the control device 10 can set a target stop position, control the traveling device 2 to stop the transport vehicle 1 at the target stop position, and also execute a notification process to notify the upper control system C of the target stop position via the communication device 9. Such an example is shown in FIG. 9. As shown in FIG. 9, when the control device 10 determines that the first target voltage V1 is equal to or less than the first judgment threshold Vt1 (S31: No), it executes the first deceleration and stop process (S32) and also executes a notification process (S33). In this example, the control device 10 sets a target stop position of the transport vehicle 1 at the same time as the first deceleration and stop process is executed. Here, the target stop position can be a position that is a specified distance forward in the travel direction X from the position of the object 43 most recently detected by the detection device 15 of the transport vehicle 1. For example, a deceleration rate of the transport vehicle 1 is set in advance, and the specified distance can be calculated based on the deceleration rate. In addition, the control device 10 may store map information of the travel route 5 and set the target stop position of the transport vehicle 1 using the map information. When executing the first deceleration and stop processing, the control device 10 executes a notification process to transmit the set target stop position to the upper control system C. Note that the control device 10 may execute the notification process after executing the first deceleration and stop processing and before completing the processing. In addition, the control device 10 may notify the upper control system C of the deceleration start position of the transport vehicle 1 as the notification process. In that case, the target stop position is calculated by the upper control system C.

[0049] (5) In the above embodiment, the power supply unit 3 is described as including the power storage device 31 that temporarily stores power, but the present invention is not limited to this. The power supply unit 3 does not necessarily have to include the power storage device 31.

[0050] (6) In the above embodiment, the control device 10 monitors the second object voltage V2 and executes the second deceleration stop process, but the present invention is not limited to this. The control device 10 may be configured not to monitor the second object voltage V2 at all. In that case, the control device 10 does not execute the second deceleration stop process. On the other hand, the control device 10 may control the lifting device 72 to accommodate the holding device 62 in the accommodation section 17 regardless of the position of the holding device 62 when the second object voltage V2 becomes equal to or lower than the second determination threshold value Vt2 in the second deceleration stop process.

[0051] (7) In the above embodiment, the control device 10 monitors the third target voltage V3 and executes the third deceleration and stop processing, but the present invention is not limited to this. The control device 10 may be configured not to monitor the third target voltage V3 at all. In that case, the control device 10 does not execute the third deceleration and stop processing. On the other hand, the control device 10 may control the lifting device 72 to accommodate the holding device 62 in the accommodation section 17 regardless of the position of the holding device 62 in the retraction direction Y when the third target voltage V3 becomes equal to or lower than the third determination threshold value Vt3 in the third deceleration and stop processing.

[0052] (8) Note that the configurations disclosed in each of the above-described embodiments can be applied in combination with configurations disclosed in other embodiments (including combinations of the embodiments described as other embodiments) as long as no contradiction occurs. With regard to other configurations, the embodiments disclosed in this specification are merely examples in all respects. Therefore, various modifications can be made as appropriate within the scope of the present disclosure.

[0053] Summary of the above embodiment The above-described transport vehicles will now be summarized.

[0054] The transport vehicle according to the present disclosure is a transport vehicle that transports an article, A traveling device having a traveling drive unit, a control device for controlling the traveling device, and a power supply unit for receiving power from an external source and supplying power to at least the traveling device and the control device, The voltage supplied from the power supply unit to the traveling device is defined as a target voltage, and the lower limit voltage required to operate the traveling device is defined as a required lower limit voltage, The control device monitors the target voltage, and when, while the transport vehicle is traveling, the target voltage falls below a judgment threshold value that is set to a value lower than the voltage during normal operation of the power supply unit and higher than the required lower limit voltage, the control device executes a deceleration and stop process that reduces the traveling speed of the transport vehicle and stops the transport vehicle from traveling.

[0055] According to this configuration, even if the voltage (target voltage) supplied to the traveling device drops below the required lower limit voltage due to a power supply failure caused by a power outage, a power supply unit failure, etc., the transportation vehicle can start decelerating when the voltage reaches the determination threshold value. Therefore, it is possible to prevent the transportation vehicle from suddenly stopping due to the traveling device becoming inoperable as a result of the target voltage falling below the required lower limit voltage. In this way, sudden stops of the transport vehicle can be avoided, and adverse effects such as large acceleration acting on the goods being transported can be mitigated.

[0056] Here, the time required from the start to the completion of the deceleration / stop process is defined as a required processing time, and the amount of decrease in the target voltage per unit time in the event of an abnormality in the power supply from the power supply unit is defined as a voltage decrease rate, It is preferable that the judgment threshold value be set to a value equal to or greater than a value obtained by multiplying the voltage drop rate by the required processing time and adding the result to the required lower limit voltage.

[0057] According to this configuration, the deceleration and stop process can be completed in the period from when the target voltage becomes equal to or lower than the judgment threshold voltage until when the target voltage becomes equal to the required lower limit voltage. Therefore, even if the voltage supplied to the traveling device drops due to a power supply failure, the transport vehicle can be appropriately decelerated and stopped.

[0058] The system further includes a communication device for communicating with a host control system that controls the plurality of transport vehicles, The control device is configured to control the traveling device based on a command from the upper control system, It is preferable that, in the deceleration and stopping process, the control device sets a target stopping position, controls the traveling device to stop the transport vehicle at the target stopping position, and also executes a notification process to notify the upper control system of the target stopping position via the communication device.

[0059] According to this configuration, the host control system can grasp the stopping position of the transport vehicle, thereby reducing the effort required for recovery processing after the power supply problem is resolved.

[0060] The power supply unit further includes a power storage device that temporarily stores power, It is preferable that the voltage of the power storage device be supplied to the traveling device.

[0061] According to this configuration, even if a power supply failure occurs, it is possible to prevent a sudden drop in the voltage supplied to the traveling device, and therefore it is easy to ensure time for the control device to execute the deceleration and stop processing.

[0062] The apparatus further includes a holding device for holding the article and a lifting device for lifting the holding device, The voltage supplied from the power supply unit to the lifting device is a second target voltage, and a lower limit voltage required to operate the lifting device is a second required lower limit voltage; It is preferable that the control device further monitors the second target voltage, and when the second target voltage falls below a second judgment threshold set to a value lower than the voltage during normal operation of the power supply unit and higher than the second required lower limit voltage during the raising and lowering operation of the holding device by the lifting device, executes a second deceleration and stop process to reduce the raising and lowering speed of the holding device by the lifting device and stop the raising and lowering of the holding device.

[0063] According to this configuration, even if the voltage (second target voltage) supplied to the lifting device drops due to a power supply failure caused by, for example, a power outage or a power supply unit failure, the lifting speed of the holding device can be started to be reduced when the voltage reaches the second determination threshold value. Therefore, it is possible to prevent the lifting device from becoming inoperable and the holding device from suddenly stopping due to the second target voltage being lower than the second required lower limit voltage. In this way, sudden stops of the holding device during lifting and lowering operations can be avoided, and adverse effects such as large acceleration acting on an article during lifting and lowering can be mitigated.

[0064] The apparatus further includes a holding device for holding the article, and a slide device for moving the holding device in a specific direction along the horizontal direction, a voltage supplied from the power supply unit to the sliding device as a third target voltage, and a lower limit voltage required to operate the sliding device as a third required lower limit voltage; It is preferable that the control device further monitors the third target voltage, and when the third target voltage falls below a third judgment threshold value set to a value lower than the voltage during normal operation of the power supply unit and higher than the third required lower limit voltage during the extension / retraction movement of the holding device by the sliding device, executes a third deceleration / stop process which reduces the extension / retraction speed of the holding device by the sliding device and stops the extension / retraction of the holding device.

[0065] According to this configuration, even if the voltage (third target voltage) supplied to the sliding device drops due to a power supply failure caused by, for example, a power outage or a power supply unit failure, the moving speed of the holding device can be started to be reduced at the point when the voltage reaches the third determination threshold value. Therefore, it is possible to prevent the sliding device from becoming inoperable and the holding device from suddenly stopping due to the third target voltage being lower than the third required lower limit voltage. In this way, sudden stops of the holding device during the extending / retracting operation can be avoided, and adverse effects such as large acceleration acting on an article moving in the extending / retracting direction can be mitigated.

[0066] It is sufficient for the transportation vehicle according to the present disclosure to achieve at least one of the effects described above. [Explanation of symbols]

[0067] 1: Transport vehicle 2: Running gear 3: Power supply unit 9: Communication equipment 21: Travel drive unit 31: Electricity storage device 62: Holding device 72: Lifting device 82: Slide device C: Upper control system Ra: First voltage drop rate (voltage drop rate) S:Target stop position Ta: First processing time (required processing time) V1: First target voltage (target voltage) V2: Second target voltage V3: Third target voltage Vs1: 1st required lower limit voltage (required lower limit voltage) Vs2: Second required lower limit voltage Vs3: Third required lower limit voltage Vt1: First judgment threshold (judgment threshold) Vt2: Second judgment threshold Vt3: Third judgment threshold Y: Exit / exit direction

Claims

1. A transport vehicle for transporting an item, A traveling device having a traveling drive unit, a control device for controlling the traveling device, and a power supply unit for receiving power from an external source and supplying power to at least the traveling device and the control device, The voltage supplied from the power supply unit to the traveling device is defined as a target voltage, and the lower limit voltage required to operate the traveling device is defined as a required lower limit voltage, The control device monitors the target voltage, and when the target voltage falls below a judgment threshold value set to a value lower than the voltage during normal operation of the power supply unit and higher than the required lower limit voltage while the transport vehicle is traveling, executes a deceleration and stop process to reduce the traveling speed of the transport vehicle and stop the transport vehicle from traveling.

2. a time required from the start to the completion of the deceleration / stop process is defined as a processing time, and a voltage drop rate is defined as a drop in the target voltage per unit time in the event of an abnormality in the power supply from the power supply unit, The transportation vehicle according to claim 1 , wherein the determination threshold value is set to be equal to or greater than a value obtained by multiplying the voltage drop rate by the required processing time and adding the result to the required lower limit voltage.

3. The transport vehicle further includes a communication device for communicating with a host control system that controls the transport vehicles, The control device is configured to control the traveling device based on a command from the upper control system, The transport vehicle of claim 1, wherein the control device, in the deceleration and stopping process, sets a target stopping position, controls the traveling device to stop the transport vehicle at the target stopping position, and also executes a notification process to notify the upper control system of the target stopping position via the communication device.

4. The power supply unit includes a power storage device that temporarily stores power, The transport vehicle according to claim 1 , wherein a voltage of the power storage device is supplied to the traveling device.

5. Further comprising a holding device for holding the article and a lifting device for lifting the holding device, The voltage supplied from the power supply unit to the lifting device is a second target voltage, and a lower limit voltage required to operate the lifting device is a second required lower limit voltage, The control device further monitors the second target voltage, and when the second target voltage becomes equal to or lower than a second judgment threshold set to a value lower than the voltage during normal operation of the power supply unit and higher than the second required lower limit voltage during the raising and lowering operation of the holding device by the lifting device, executes a second deceleration and stop process to reduce the raising and lowering speed of the holding device by the lifting device and stop the raising and lowering of the holding device.

6. The apparatus further includes a holding device for holding the article, and a slide device for moving the holding device in a specific direction along a horizontal direction, The voltage supplied from the power supply unit to the sliding device is a third target voltage, and a lower limit voltage required to operate the sliding device is a third required lower limit voltage, The control device further monitors the third target voltage, and when the third target voltage becomes equal to or lower than a third judgment threshold set to a value lower than the voltage during normal operation of the power supply unit and higher than the third required lower limit voltage during the extension / retraction movement of the holding device by the sliding device, executes a third deceleration / stop process to reduce the extension / retraction speed of the holding device by the sliding device and stop the extension / retraction of the holding device.A transport vehicle as described in any one of claims 1 to 3.

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