CONVEYANCE SYSTEM, CONVEYANCE METHOD, AND PROGRAM

A conveyance system, a conveyance method, and a program that are capable of preventing an article stored in a shelf from falling are provided. A conveyance system according to one aspect of the present disclosure includes: a shelf provided with a guide rail extending in a vertical direction; a mounting table that is engageable with the guide rail; a lifting part configured to lift the mounting table up and down; an engagement detection sensor configured to detect engagement between the guide rail and the mounting table; and a safety control unit configured to stop an operation of the lifting part when a first condition including that the guide rail is not engaged with the mounting table is satisfied.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from Japanese patent application No. 2022-166012, filed on Oct. 17, 2022, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

The present disclosure relates to a conveyance system, a conveyance method, and a program.

Japanese Patent No. 6413899 discloses a conveyance robot that places an article on a carriage and conveys it.

SUMMARY

As means for storing an article placed on a carriage in a shelf or for placing an article stored in a shelf on a carriage, it is conceivable that a guide rail is provided in a shelf so that a mounting table is lifted up along the guide rail. In this case, however, there is a problem that when the mounting table that is not engaged with the guide rail is lifted up, an article may fall.

The present disclosure has been made in view of the above-described problem and provides a conveyance system, a conveyance method, and a program that are capable of preventing an article stored in a shelf from falling.

A conveyance system according to one aspect of the present disclosure includes:a shelf provided with a guide rail extending in a vertical direction;a mounting table that is engageable with the guide rail;a lifting part configured to lift the mounting table up and down;an engagement detection sensor configured to detect engagement between the guide rail and the mounting table; anda safety control unit configured to stop an operation of the lifting part when a first condition including that the guide rail is not engaged with the mounting table is satisfied.

A conveyance method according to one aspect of the present disclosure includes:detecting engagement between a guide rail and a mounting table, the guide rail extending in a vertical direction and being provided in a shelf, and the mounting table being engageable with the guide rail; andstopping, when a first condition including that the guide rail is not engaged with the mounting table is satisfied, an operation of a lifting part configured to lift the mounting table up and down.

A program according to one aspect of the present disclosure causes a computer to:acquire a result of detection by a sensor configured to detect engagement between a guide rail and a mounting table, the guide rail extending in a vertical direction and being provided in a shelf, and the mounting table being engageable with the guide rail; andstop, when a first condition including that the guide rail is not engaged with the mounting table is satisfied, an operation of a lifting part configured to lift the mounting table up and down.

According to the present disclosure, it is possible to provide a conveyance system, a conveyance method, and a program that are capable of preventing an article stored in a shelf from falling.

DESCRIPTION OF EMBODIMENTS

Specific embodiments to which the present disclosure is applied will be described hereinafter in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. Further, for the clarification of the description, the following descriptions and the drawings are simplified as appropriate.

First Embodiment

A conveyance system1according to a first embodiment will be described below with reference to the drawings.FIG.1is a diagram for explaining an outline of the conveyance system1. The conveyance system1includes a shelf11and a conveyance robot12. The conveyance robot12conveyances an article and stores it in the shelf11. The conveyance robot12takes out an article from the shelf11and conveys the article that has been taken out.

The shelf11holds an article that is not shown. Examples of the article may include a returnable box. The shelf11includes a housing111, a support member112, and a guide rail113. The support member112supports an article stored in the shelf11(seeFIG.2).

The guide rail113engages a groove1211provided in a mounting table121of the conveyance robot12. The guide rail113extends in the vertical direction. The guide rail113may be a plate-like member provided so as to be parallel to a front surface of the shelf11. The plate-like member protrudes inwardly from the housing111. The guide rail113may be provided on each of the left and right sides of the housing111, or may instead be provided on one of the left and right sides thereof.

The conveyance robot12includes the mounting table121, a moving part122, a lifting part123, an extendable arm124, and an engagement detection sensor125. The mounting table121is a table on which an article can be placed and is also referred to as a top plate. The groove1211is provided in the mounting table121. The groove1211is engaged with the guide rail113of the shelf11. The groove1211may be provided on each of the right and left sides of the conveyance robot12with respect to a direction in which the conveyance robot12travels.

The conveyance robot12is moved in the horizontal direction by the movable moving part122. The lifting part123is provided on the moving part122. The lifting part123lifts the mounting table121up and down. The extendable arm124extends and contracts in the horizontal direction. The extendable arm124takes out an article from the shelf11and places the article on the mounting table121, and stores the article placed on the mounting table121in the shelf11.

Note that the extendable arm124may be provided on the shelf11side. Further, an article may be transferred by a mechanism other than the extendable arm124. Further, the conveyance robot12may be fixed to a position near the shelf11. In this case, the conveyance robot12may not include the moving part122.

The engagement detection sensor125is provided in the groove1211. The engagement detection sensor125detects that the guide rail113is engaged with the groove1211. When the guide rail113is engaged with the groove1211, the guide rail113is engaged with the mounting table121. The engagement detection sensor125is, for example, a photo interrupter or a photo reflector. In this case, the engagement detection sensor125includes a light emitting unit and a light receiving unit. When the light from the light emitting unit is blocked by the guide rail113, the engagement detection sensor125may detect that the guide rail113is engaged with the mounting table121. When the light from the light emitting unit is reflected by the guide rail113, the engagement detection sensor125may detect that the guide rail113is engaged with the mounting table121. Note that the engagement detection sensor125may be a sensor (e.g., a contact sensor and a magnetic sensor) that detects a force received from the guide rail113.

Note that the conveyance system1may include a server (not shown) that controls traveling of the conveyance robot12. The conveyance robot12may generate a conveyance route by itself and move autonomously. The conveyance system1may include a system which does not include a server and in which processing is completed in the conveyance robot12.

An example of a structure of the shelf11will be described in detail with reference toFIG.2. Note that, for the clarification of the description, a three-dimensional orthogonal coordinate system of xyz is shown. The z direction is the vertical direction.

The shelf11includes the housing111, the support member112, the guide rail113, and partition plates114.

The housing111has a structure in which a top plate provided on the z-axis positive side, a bottom plate provided on the z-axis negative side, a left side plate provided on the y-axis positive side, and a right side plate provided on the y-axis negative side are integrally formed. A rear surface of the housing111may be closed by a rear plate. The bottom plate of the housing111may be thinly formed so that the conveyance robot12can enter the inside of the housing111. Further, the housing111may not include a bottom plate.

The support members112extend in the depth direction (the x-axis direction) and are arranged at equal intervals in the height direction (the z-axis direction) on the inner surfaces of the housing111and on the partition plate114described later. Protrusion parts that protrude outwardly from an article2in the width direction thereof slide on the respective pairs of adjacent support members112that face each other, whereby the article2can be put into the shelf11and taken out of the shelf11. Note that the support member112may support the bottom surface of the article2. In this case, the article2may not include a protrusion part.

The guide rail113extends in the vertical direction (the z-axis direction). The guide rail113may be a plate-like member parallel to the yz plane. The plate-like member is provided so as to rise substantially vertically from the inner surface of the side plate and the partition plate114.

A gap into which the conveyance robot12enters is formed between the ground or the bottom plate of the housing111and the lower end of the guide rail113. A condition in which the lifting part123of the conveyance robot12is contracted is shown by a dotted line. The distance between two adjacent guide rails113that face each other is greater than the width of the article2. When the article2is put into the shelf11and taken out of the shelf11, the guide rail113and the article2do not interfere with each other. A notch (a slot) through which the protrusion part of the article2passes may be provided in the guide rail113. In this case, the width of the article2may be greater than the distance between the guide rails113.

The partition plates114are provided so as to be parallel to the right and left side plates of the housing111, that is, so as to be parallel to the xz plane, and so as to be extended from the front surface of the housing111to the rear surface of the same. The partition plates114are provided so that an interval between the right side plate of the housing111and the adjacent partition plate114, an interval between the left side plate of the housing111and the adjacent partition plate114, and an interval between the partition plates114are equal to each other. Note that, in the example shown inFIG.2, although two partition plates114are provided, the number of partition plates114is not limited to any particular number. Further, the partition plate114may not be provided.

Next, the conveyance robot12will be described with reference toFIGS.3,4, and5.FIG.3is a perspective view showing a configuration of the conveyance robot12.FIG.4is a side view showing the configuration of the conveyance robot12.FIG.5is a block diagram showing a functional configuration of the conveyance robot12.

As shown inFIGS.3and4, the conveyance robot12includes the mounting table121, the moving part122, the lifting part123, the extendable arm124, and the engagement detection sensor125. As shown inFIG.5, the conveyance robot12includes a control unit126and a safety control unit127. The control unit126controls normal operations performed by the moving part122, the lifting part123, and the extendable arm124. The safety control unit127stops (e.g., urgently stops) the operation of the lifting part123based on a result of detection by the engagement detection sensor125. The safety control unit127may further stop the operations of the moving part122and the extendable arm124.

The groove1211extending in the vertical direction is provided on the side surface of the mounting table121. The groove1211is provided from the lower surface of the mounting table121to the upper surface of the same. The groove1211is engageable with the guide rail113.

The moving part122includes a moving-part body1221, a pair of right and left driving wheels1222rotatably disposed in the moving-part body1221, a pair of front and rear driven wheels1223rotatably disposed in the moving-part body1221, and a pair of motors1224that rotationally drive the respective driving wheels1222. Each of the motors1224rotates a respective one of the driving wheels1222through a speed reducer or the like. Each of the motors1224rotates a respective one of the driving wheels1222in accordance with a control signal sent from the control unit126. Each of the motors1224rotates a respective one of the driving wheels1222in accordance with a control signal sent from the control unit126, thereby enabling the moving-part body1221to move to any position. Note that the above-described configuration of the moving part122is merely an example and the configuration of the moving part122is not limited to this example. For example, the number of driving wheels1222of the moving part122and the number of driven wheels1223of the moving part122may be any number, and any configuration in which the moving-part body1221can be moved to any position may be used.

The mounting table121is lifted up and down by the lifting part123extending and contracting. The lifting part123may be formed as a telescopic expanding/contracting mechanism that extends and contracts in the vertical direction. The extendable arm124is attached to the mounting table121. The extendable arm124includes an arm body1241and a driving apparatus1242. The driving apparatus1242, which is attached to a guide rail mechanism (not shown) in the mounting table121, moves the arm body1241in the horizontal direction. The driving apparatus1242may further include a mechanism that rotates the arm body1241around the axis.

The engagement detection sensor125is provided in the groove1211. The engagement detection sensor125may be provided on each of the left and right sides of the mounting table121. The engagement detection sensor125can detect that the groove1211is engaged with the guide rail113. The conveyance robot12may further include a movement detection sensor that detects movement of the moving part122and a height detection sensor that detects a height of the mounting table121.

The control unit126controls normal operations of the moving part122, the lifting part123, and the extendable arm124. The control unit126can control the rotation of each of the driving wheels1222and move the moving-part body1221to any position by transmitting a control signal to each of the motors1224of the moving part122. The control unit126can control a height position of the mounting table121by transmitting a control signal to a rotating apparatus1231of the lifting part123. The control unit126can also control a horizontal position of the arm body1241by transmitting a control signal to the driving apparatus1242of the extendable arm124.

The control unit126may control the movement of the moving-part body1221by performing well-known control such as feedback control and robust control based on information about the rotations of the driving wheels1222detected by a rotation sensor(s) provided in the driving wheels1222. Further, the control unit126may control the operations of the moving part122, the lifting part123, and the extendable arm124based on information such as information about a distance(s) detected by a distance sensor such as a camera or an ultrasonic sensor provided in the moving-part body1221and information about a map of the moving environment.

The control unit126is composed mainly of, for example, hardware such as a microcomputer including a Central Processing Unit (CPU)1261that performs control processing, arithmetic processing, and the like, a memory1262including Read Only Memory (ROM) that stores a control program, an arithmetic program, and the like executed by the CPU1261, and an interface unit (I/F)1263that inputs and outputs signals from and to the outside. The CPU1261, the memory1262, and the interface unit1263are connected to one another through a data bus or the like.

The safety control unit127acquires a result of detection by the engagement detection sensor125. The safety control unit127may further acquire a result of detection by a sensor other than the engagement detection sensor125. The safety control unit127stops the operation of the lifting part123when a first condition including that the guide rail113is not engaged with the mounting table121is satisfied.

Like the control unit126, the safety control unit127may include a processor, a memory, and the like. The safety control unit127may be a Programmable Logic Controller (PLC).

The first condition may further include that a height of the mounting table121is greater than or equal to a predetermined height h1. When the safety control unit127stops the operation of the lifting part123, the safety control unit127may stop the supply of power to the lifting part123.

Note that when the guide rail113is engaged with the mounting table121, it is not necessary to extend the lifting part123in some cases. For example, when the mounting table121is configured so that it can be tilted, the guide rail113can, upon the mounting table121being tilted, engage therewith. Further, for example, when the guide rail113is provided on one side of the shelf11, the guide rail113can be engaged with the mounting table121by the conveyance robot12moving in a direction parallel to the front surface of the shelf11. In such a case, the first condition may not include a condition regarding the height of the mounting table121.

According to the first embodiment, when the guide rail is not engaged with the mounting table, the operation of the mounting table can be stopped. By this structure, it is possible to prevent an article stored in the shelf from falling.

It is also possible to prevent the conveyance robot from falling.

Second Embodiment

A second embodiment is a specific example of the first embodiment.FIG.6is a side view showing a configuration of a conveyance robot12aaccording to the second embodiment. The conveyance robot12ashown inFIG.6further includes a height detection sensor128in addition to the components shown inFIG.4. The height detection sensor128measures a height of the mounting table121. The height detection sensor128is not required to be capable of measuring a height of the mounting table121in millimeters or centimeters. The height detection sensor128is only required to be capable of detecting that the height of the mounting table121is greater than or equal to the predetermined height h1.

The height detection sensor128may measure a height of the mounting table121by capturing an image of the lifting part123expanding and contracting. For example, in a case in which a plurality of cylinders included in the telescopic lifting part123have different colors, it is possible to determine that the height of the mounting table121is greater than or equal to the predetermined height h1 when a cylinder of a new color appears. When the lifting part123is formed by winding a plurality of bands therearound, each of the bands includes a plurality of parts having different colors. When the length of the lifting part123exceeds a predetermined length, new parts having different colors may appear.

Further, the height detection sensor128may be a distance measurement sensor that measures a distance between the lower surface of the mounting table121and the upper surface of the moving-part body1221. In this case, the height detection sensor128may be provided on the upper surface of the moving-part body1221or the lower surface of the mounting table121. Further, the height detection sensor128may measure a distance between the mounting table121and the ground. The height detection sensor128may be a magnetic detection mechanism.

FIG.7is a block diagram showing a functional configuration of the conveyance robot12a. The conveyance robot12aincludes the moving part122, the lifting part123, the extendable arm124, the engagement detection sensor125, the control unit126, the safety control unit127, the height detection sensor128, a power source129, a relay130, and a relay131.

The control unit126provides commands to control the moving part122, the lifting part123, and the extendable arm124. The control unit126is also referred to as a robot control apparatus. The control unit126is, for example, a Personal Computer (PC).

The safety control unit127acquires a result of the detection by the engagement detection sensor125and a result of the detection by the height detection sensor128. The safety control unit127performs control to change the state of the relay130and the state of the relay131based on the acquired results of the detection. The safety control unit127is also referred to as a safety control apparatus. The safety control unit127is implemented by, for example, a PLC.

When the first condition described above is satisfied, the safety control unit127brings the relay130into an interrupting state. By doing so, the movement of the lifting part123and the movement of the extendable arm124are stopped. The first condition includes that the guide rail113is not engaged with the mounting table121and that the height of the mounting table121is greater than or equal to the predetermined height h1. The predetermined height h1 is set greater than the height at which the lower end of the guide rail113is located. The predetermined height h1 is set appropriately in accordance with the level of risk of the article falling etc.

When the first condition is satisfied, the mounting table121has not been lifted up along the guide rail113. By the safety control unit127stopping the operation of the lifting part123, it is possible to reduce the level of risk of the article2falling and the level of risk of the conveyance robot12falling.

Further, when the first condition is satisfied, the extendable arm124that has been extended may come into contact with a user. When the mounting table121has been lifted up to about the eye level of a user, the level of risk of the extendable arm124coming into contact with a user is particularly high. By the safety control unit127stopping the operation of the extendable arm124, it is possible to reduce the level of risk of the extendable arm124coming into contact with a user.

When a second condition including that the guide rail113is engaged with the mounting table121is satisfied, the safety control unit127further puts the relay131into an interrupting state. By doing so, the operation of the moving part122is stopped. The safety control unit127may also stop the operation of the moving part122when the first condition is satisfied.

When the moving part122is operated when the second condition is satisfied, there is a risk of the mounting table121and the lifting part123being damaged. Further, there is a risk of the article2falling from the shelf11and the mounting table121. By stopping the operation of the moving part122, it is possible to reduce the level of risk of the conveyance robot12being damaged and the level of risk of the article2falling.

The power source129supplies power to the moving part122, the lifting part123, and the extendable arm124. A wiring21is a wiring for supplying power to the lifting part123and the extendable arm124. A wiring22is a wiring for supplying power to the moving part122.

The relay130(also referred to as a relay 1) is provided on the wiring21. The relay130is also referred to as a first interrupting part. The relay130interrupts the supply of the power source129to the lifting part123and the extendable arm124. The relay130switches the connection state between each of the lifting part123and the extendable arm124and the power source129in response to a control signal sent from the safety control unit127.

The relay131(also referred to as a relay 2) is provided on the wiring22. The relay131is also referred to as a second interrupting part. The relay131interrupts the supply of the power source129to the moving part122. The relay131switches the connection state between the moving part122and the power source129in response to a control signal sent from the safety control unit127.

Note that a driving source such as high-pressure air or oil may be used instead of the power source129. In this case, the first and the second interrupting parts are composed of valves and the like.

Next, an outline of operations performed by the conveyance robot12awill be described with reference toFIGS.8and9.FIG.8shows a state before the mounting table121is engaged with the guide rail113. The moving part122moves so that the position of the groove1211in the x direction substantially coincides with the position of the guide rail113in the x direction. When the lifting part123lifts up the mounting table121to the height at which the lower end of the guide rail113is located, engagement between the mounting table121and the guide rail113is started. When the mounting table121is engaged with the guide rail113, the safety control unit127stops the operation of the moving part122.

FIG.9shows a state in which the mounting table121has been lifted up to the height of the article2. Since the mounting table121is engaged with the guide rail113, the safety control unit127does not stop the operation of the lifting part123and the operation of the extendable arm124. The conveyance robot12aplaces a load on the mounting table121by using the extendable arm124. On the other hand, when the guide rail113is not engaged with the mounting table121, the safety control unit127stops the operation of the lifting part123.

FIG.10is a diagram for explaining an operation of the safety control unit127. The first column of Table30shows the results of the detection by the engagement detection sensor125. The second column of Table30shows the results of the detection by the height detection sensor128. The third column of Table30shows the connection status of the relay 1 (the relay130). In the table, “ON” indicates a connecting state, while “OFF” indicates an interrupting state. The fourth column of Table30shows the connection status of the relay 2 (the relay131).

First, the state of the relay 1 will be described. As shown in the fourth row of Table30, when the first condition is satisfied, that is, when the mounting table121is not engaged with the guide rail113and the height of the mounting table121is greater than or equal to the predetermined height h1, the state of the relay 1 is an interrupting state. When the height of the mounting table121becomes greater than or equal to the predetermined height h1 without the mounting table121being engaged with the guide rail113due to an unintended lifting up/down of the mounting table121or a failure of engagement between the mounting table121and the guide rail113, the supply of the power source129to the lifting part123is stopped. Then, the lifting part123is brought into a safety torque off state.

Next, the state of the relay 2 will be described. As shown in the second and the third rows of Table30, when the second condition is satisfied, that is, when the mounting table121is engaged with the guide rail113, the relay 2 is in an interrupting state. Further, as shown in the fourth row of Table30, the relay 2 is in an interrupting state even when the first condition is satisfied.

Note that in a case in which the operation of the moving part122is required when the guide rail113is engaged with the mounting table121, the state of the relay131may be set to “ON” in the second row of Table30. In this case, since the height of the mounting table121is low, the level of risk of the lifting part123being damaged and the level of risk of an article falling are low. Although it is considered that the appropriate predetermined height h1 is about 1 m, it may be set appropriately in accordance with the respective level of risk factors, such as the weight of an article.

A relay (also referred to as a third interrupting part) that interrupts the supply of the power source129to the extendable arm124may be provided separately from the relay131that interrupts the supply of the power source129to the lifting part123. In this case, when the guide rail113is not engaged with the mounting table121and the height of the mounting table121is greater than or equal to a height h2 different from the predetermined height h1, the relay is brought into an interrupting state. By the above structure, the condition for stopping the extendable arm124can be set to a condition different from the condition for stopping the lifting part123.

The second embodiment can provide advantageous effects similar to those in the case of the first embodiment. Further, the second embodiment can reduce the level of risk due to the movement of the conveyance robot12that is engaged with the shelf11. The second embodiment can reduce the level of risk due to the extension of the extendable arm124by the conveyance robot12that is not engaged with the shelf11.

Third Embodiment

A third embodiment is a modified example of the second embodiment.FIG.11is a block diagram showing a functional configuration of a conveyance robot12baccording to the third embodiment. The conveyance robot12bshown inFIG.11further includes a movement detection sensor132in addition to the components shown inFIG.7. The wirings21and22are replaced by a wiring23. The relays130and131are replaced by a relay133.

The movement detection sensor132detects movement performed by the moving part122. The movement detection sensor132may be a speed monitoring sensor that monitors a speed of the moving part122. The speed may be monitored based on, for example, a rotational speed of the motor1224. Further, the movement detection sensor132may be a sensor that measures a distance between a surrounding environment and the conveyance robot12. Movement performed by the moving part122is detected when there is a change in the measured distance.

The wiring23is a wiring for supplying power to the moving part122, the lifting part123, and the extendable arm124.

The relay133is provided on the wiring23. The relay133may be referred to simply as a relay. The relay133is also referred to as a fourth interrupting part. The relay133interrupts the supply of the power source129to the moving part122, the lifting part123, and the extendable arm124. The relay133switches the connection state between each of the moving part122, the lifting part123, and the extendable arm124and the power source129in response to a control signal sent from the safety control unit127.

When the first condition is satisfied, the safety control unit127brings the relay133into an interrupting state. Further, when the second condition is satisfied, the safety control unit127brings the relay133into an interrupting state. The second condition includes that the guide rail113is engaged with the mounting table121, that the height of the mounting table121is greater than or equal to the predetermined height h1, and that the moving part122is moving.

FIG.12is a diagram for explaining an operation of the safety control unit127. The third column of Table40shows the results of the detection by the movement detection sensor132. In the table, “x” indicates “don't care”. In the table, “=0” indicates that the speed of the moving part122is 0, that is, the moving part122is not moving. In the table, “>0” indicates that the speed of the moving part122is not 0, that is, the moving part122is moving. The fourth column of Table40shows the connection state of the relay133(relay).

As shown in the fourth row of Table40, when the first condition is satisfied, the relay133is “OFF”.

As shown in the fifth row of Table40, when the second condition is satisfied, the relay133is “OFF”. When the second condition is satisfied, the relay133is “OFF” and the speed of the moving part122is 0. Therefore, the current state is transitioned from the state shown in the fifth row of Table40to the state shown in the third row of Table40. As a result, the state in which the lifting part123or the like can be damaged is transitioned to a safe state.

As shown in the second row of Table40, the moving part122can be moved while the mounting table121is engaged with the guide rail113. However, since the height of the mounting table121is less than the predetermined height h1, the level of risk of the lifting part123and the like being damaged and the level of risk of an article falling are low. The conveyance robot12bcan engage the guide rail113with the mounting table121while moving.

Note that the conveyance robot12bmay not include the extendable arm124. In this case, the level of risk (e.g., the level of risk of the article2falling) other than the risk of the extendable arm124coming into contact with a user can be reduced.

The third embodiment can provide advantageous effects similar to those in the case of the second embodiment. The number of interrupting parts used in the third embodiment is less than the number of interrupting parts used in the second embodiment.

The above-described program includes instructions (or software codes) that, when loaded into a computer, cause the computer to perform one or more of the functions. The program may be stored in a non-transitory computer readable medium or a tangible storage medium. By way of example, and not a limitation, non-transitory computer readable media or tangible storage media can include a Random-Access Memory (RAM), a Read-Only Memory (ROM), a flash memory, a Solid-State Drive (SSD) or other types of memory technologies, a CD-ROM, a Digital Versatile Disc (DVD), a Blu-ray (Registered Trademark) disc or other types of optical disc storage, and magnetic cassettes, magnetic tape, magnetic disk storage or other types of magnetic storage devices. The program may be transmitted on a transitory computer readable medium or a communication medium. By way of example, and not a limitation, transitory computer readable media or communication media can include electrical, optical, acoustical, or other forms of propagated signals.

Note that the present disclosure is not limited to the above-described embodiments and may be changed as appropriate without departing from the scope and spirit of the present disclosure.

For example, the engagement detection sensor125, the height detection sensor128, and the movement detection sensor132may be provided on the shelf11side. In this case, each of these sensors may transmit a result of the detection to the conveyance robot12or a server.

Further, the conveyance system according to the embodiments may include a conveyance robot12cin which the shelf11is integrated with the conveyance robot12.FIG.13is a side view showing a configuration of the conveyance robot12c. The mounting table121may be rotatable about a vertical axis. In this case, the level of risk of an article falling, the level of risk of the lifting part123being damaged, the level of risk of the extendable arm124being brought into contact with a user, and the like can be reduced.