JP7540331B2 - Transport vehicle - Google Patents

Description

The present invention relates to a transport vehicle, and in particular to a transport vehicle having a transfer device that extends and retracts an arm to transfer cargo.

Conventionally, there is a side-arm type transfer device equipped with a pair of side arms. In a loading operation, the side-arm type transfer device extends a pair of side arms on both sides of an object placed on a shelf or the like, hooks both sides of the object with the pair of side arms, or sandwiches the object with the pair of side arms, and then retracts the side arms to transfer the object to the side-arm type transfer device.
Among slide fork type transfer devices, there is known one that is provided with a position detection device that detects the position of the slide fork (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 7-187315

In the past, for example, in order to return the slide arm of a rear hook transfer machine to its origin, an origin sensor was required to detect the origin position, and a slide area sensor (one pair on the left and one pair on the right) was required to determine whether the slide arm was extended to the left or right.
Usually, immediately after powering on, the controller cannot grasp the current position of the slide arm. Therefore, the controller first checks which pair of slide area sensors (left or right) is ON, and then moves the slide arm toward the origin (toward the center) until it detects the origin sensor, thereby locating the origin position.

As mentioned above, conventional transfer devices use three dedicated sensors (origin sensor, slide area sensor (one pair each on the left and right)) just to determine the slide origin position, which requires costs for the sensors themselves, wiring materials, and relay boards on the wiring path.

The object of the present invention is to perform origin setting of the arm of an arm-type transfer device mounted on a transport vehicle using a simple configuration.

Below, we will explain several aspects as a means to solve the problem. These aspects can be combined as needed.

A transport vehicle according to one aspect of the present invention includes a transport vehicle body, an arm-type transfer device, an arm movement amount detection sensor, a pair of load sensors, and a controller.
The arm-type transfer device is a device for transferring luggage between the transport vehicle body and other devices, and has an arm and a forward/backward drive motor for moving the arm forward and backward in both directions. The arm-type transfer device is mounted on the transport vehicle body. The "arm" here refers to a member that extends in the transfer direction and moves in the transfer direction during the transfer operation to move the luggage.
The arm movement amount detection sensor detects the amount of advancement and retreat of the arm.
The pair of load sensors are arranged on both sides of the end of the transport vehicle body in the transfer direction and are capable of detecting the load and the arm.
The controller grasps the center position of the arm in the transfer direction.
The controller has a non-detection confirming means, one-way movement means, one-way position storing means, other-way movement means, movement amount grasping means, half movement amount movement means, and center position storing means.
The non-detection confirmation means confirms that the arm is not detected by the pair of load sensors.
The one moving means moves the arm in one of the transfer directions until one of the pair of load sensors detects the load.
The one-side position storage means stores the value of the arm movement amount detection sensor when one of the pair of load sensors detects the arm. Note that "storing the value of the arm movement amount detection sensor" also includes presetting the value of the arm movement amount detection sensor (i.e., setting it to 0).
The other moving means moves the arm in the other direction in the transfer direction until the other of the pair of load sensors detects the load.
The movement amount grasping means grasps the amount of movement between the detection positions from the value of the arm movement amount detection sensor when the other of the pair of load sensors detects the arm and the value of the arm movement amount detection sensor stored in the one position memory means.
The half-travel distance moving means moves the arm in one direction by half the distance of the movement between the detection positions.
The central position storage means stores the value of the arm movement amount detection sensor when the arm has moved halfway as the central position.

In this transport vehicle, for example, the origin position in the transfer direction immediately after power is turned on is set in the following procedure, for example.
First, it is determined that the arm is not being detected by a pair of load sensors.
Next, the arm is moved in one of the transfer directions until one of the pair of load sensors detects the load.
Next, the value of the arm movement amount detection sensor when one of the pair of load sensors detects the arm is stored.
Next, the arm is moved in the other direction of the transfer direction until the other of the pair of load sensors detects the load.
Next, the amount of movement between the detection positions is grasped from the value of the arm movement detection sensor when the other of the pair of load sensors detects the arm and the value of the arm movement detection sensor stored in the one position storage means.
The arm is then moved in one direction by half the amount of movement between the detection positions.
Next, the value of the arm movement amount detection sensor when the arm has moved halfway is stored as the center position.
This transport vehicle can grasp the center position (origin) of the side arm in the transfer direction by using a load sensor, so there is no need to install a dedicated sensor. In other words, origin sensors and slide area sensors can be eliminated, reducing the cost of the vehicle. In addition, by reducing the number of sensors, the number of adjustment man-hours and pre-shipment inspection items can also be reduced, resulting in a reduction in total costs.

The arms may be a pair of side arms, and may be rear hook type side arms having a side arm body and hooks rotatably provided on both ends of the side arm body in the transfer direction.
The load sensor may be provided at a position for detecting a portion of the pair of side arms that is below the hook.
With this transport vehicle, opening and closing of the hook does not affect the detection results.

The controller may further include an arm advance direction detection means for determining the direction in which the arm is advanced based on the detection result of the load sensor.
This transport vehicle also uses a load sensor to detect the direction in which the arm is moving forward. This allows the motor rotation direction to be accurately determined when returning the arm. Also, a single sensor can detect load position, return to origin, and detect the arm's forward direction.

The controller may further include an object determination means for determining whether the luggage is protruding or the arm is advanced when the luggage sensor detects an object.
This transport vehicle can accurately grasp the detection results of the load sensor.

The transport vehicle of the present invention has a simple configuration that allows the arm of the arm-type transfer device loaded on the transport vehicle to be set to its original position.

FIG. 2 is a side view of the automated warehouse according to the first embodiment. Schematic floor plan of an automated warehouse. FIG. FIG. FIG. 2 is a functional block diagram showing the control configuration of an automated warehouse. FIG. 4 is a functional block diagram showing a control configuration of the transport vehicle. 11 is a flowchart showing a control operation for setting the origin position in the transfer direction. 13 is a schematic diagram showing an example of the positions of the pair of side arms in the transfer direction during a control operation for setting the origin position in the transfer direction; FIG. 13 is a schematic diagram showing an example of the positions of the pair of side arms in the transfer direction during a control operation for setting the origin position in the transfer direction; FIG. 13 is a schematic diagram showing an example of the positions of the pair of side arms in the transfer direction during a control operation for setting the origin position in the transfer direction; FIG. 13 is a schematic diagram showing an example of the positions of the pair of side arms in the transfer direction during a control operation for setting the origin position in the transfer direction; FIG. 4 is a flowchart showing a detected object determination control operation. FIG. 13 is a schematic diagram showing an example of the positions of the pair of side arms in the transfer direction during a detected object determination control operation. FIG. 13 is a schematic diagram showing an example of the positions of the pair of side arms in the transfer direction during a detected object determination control operation. FIG. 13 is a schematic diagram showing an example of the positions of the pair of side arms in the transfer direction during a detected object determination control operation. FIG. 13 is a schematic diagram showing an example of the positions of the pair of side arms in the transfer direction during a detected object determination control operation.

1. First embodiment (1) Description of the entire automated warehouse An automated warehouse 100 according to the first embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a side view of the automated warehouse of the first embodiment. Fig. 2 is a schematic plan view of the automated warehouse. In the following description, the left-right direction in Fig. 1 is referred to as a first direction (arrow Y), the depth direction of the paper surface of Fig. 1 is referred to as a second direction (arrow X), and the up-down direction in Fig. 1 is the vertical direction (arrow Z).
The automated warehouse 100 has a plurality of shelves 21 and is a system capable of storing luggage W (FIG. 4) on each shelf 21 or retrieving luggage W stored on each shelf 21.
The automated warehouse 100 includes a rack 1, a plurality of transport vehicles 3, an entrance station 7, an exit station 9, an entrance lifting device 11, and an exit lifting device 13.

A pair of racks 1 and transport vehicles 3 constitute a unit 4, and the automated warehouse 100 has a plurality of units 4. The numbers of the units 4 may be expressed as a "system," and the units 4 are a type of automated warehouse unit.
In unit 4, the luggage W is carried in from an input conveyor (not shown) to a storage station 7. Also, in unit 4, the luggage W is carried out from a delivery station 9 to an output conveyor (not shown). The destination of the output conveyor is a sorting area where the luggage W is collected for each shipping destination and shipped by truck or the like, or a picking area where products are picked from the luggage W, etc.

(2) Rack Each shelf level 21 of the rack 1 extends long in the first direction and has multiple openings 22. Each opening 22 is a unit of shelf level on which luggage W is placed, and has the same length in the first direction. The openings 22 extend from a first end opening 22a at the front end in the traveling direction (the side of the loading station 7 and the outgoing station 9 described later in the first direction) to a second end opening 22b at the rear end in the traveling direction (the side opposite the loading station 7 and the outgoing station 9 described later in the first direction).
The shelves 21 are arranged on both sides in the second direction with respect to the transport vehicle 3 and the rail 5 (described later).

Each opening 22 can store a plurality of packages W. The openings 22 may be separate or integrally formed. In other words, a single shelf board constituting the shelf level 21 may be divided to form a plurality of openings 22 in the shelf level 21.
The luggage W is a case, tray, cardboard box, collapsible container, etc., and contains goods.

(3) Transport Vehicles The multiple transport vehicles 3 are each capable of traveling along the first direction at a height corresponding to each shelf level 21. Specifically, rails 5 extending linearly in the first direction are laid at a height corresponding to each shelf level 21, and the transport vehicles 3 can travel back and forth in the first direction on the rails 5. In other words, the transport vehicles 3 are shuttle carriages.

(4) Transfer Device The transport vehicle 3 has a transfer device 15. The transfer device 15 is a device that transfers the luggage W in the second direction between the transport vehicle body 3a and the corresponding opening 22 of the shelf 21. The transfer device 15 is a rear hook type side arm, and takes in or drops the luggage W by hooking a hook (described later) on the rear end, which is the rear end in the direction in which the luggage W moves.
The transport vehicle 3 has a travel motor 41 (FIG. 6).

The transfer device 15 will be further described with reference to Figures 3 and 4. Figure 3 is a perspective view of the transfer device. Figure 4 is a schematic side view of the transfer device.
The transfer device 15 has a main body 31 and a pair of side arms 33. The main body 31 is a stationary fixed member fixed to or integrally formed with the transport vehicle main body 3a, and has a platform 37 for carrying luggage W in the transfer device 15, and the pair of side arms 33 are members that move relatively to each other as described later. The main body 31 may have a belt conveyor.

(4-1) Side Arms The pair of side arms 33 extend in the second direction and are members that move in the second direction relative to the main body 31 during a transfer operation to move the luggage W. The pair of side arms 33 are disposed at a predetermined distance in the first direction.
The transfer device 15 has a transfer motor 43 (an example of a forward/backward drive motor, FIG. 6) for moving the pair of side arms 33 forward and backward in both of the second directions, and a power transmission mechanism (not shown).

Each of the pair of side arms 33 has a side arm body 33a and a hook 33b rotatably provided on both ends of the side arm body 33a in the second direction.
Each of the hooks 33b can rotate about a rotation axis parallel to the second direction between an engaged position where it protrudes inward in the first direction with respect to the space inside the pair of side arms 33 and a disengaged position where it protrudes upward and retreats from the space. The hooks 33b are moved between the engaged position and the disengaged position by a hook motor 45 (FIG. 6).

(4-2) Opening/Closing Drive Mechanism The transfer device 15 has an opening/closing motor 47 (FIG. 6) and an opening/closing mechanism (not shown). The opening/closing mechanism is a known technique, and is a mechanism for moving one or both of the pair of side arms 33 toward and away from each other. This allows the transfer device 15 to transfer cargo W of different sizes by changing the distance between the pair of side arms 33.

(4-3) Arm Movement Amount Detection Sensor The transfer device 15 has an arm movement amount detection sensor 71 (FIG. 6). The arm movement amount detection sensor 71 detects the amount of forward and backward movement of the pair of side arms 33. Specifically, the arm movement amount detection sensor 71 is an encoder attached to the transfer motor 43. The arm movement amount detection sensor may be an encoder attached to a pulley of a drive belt.

(4-4) Load Sensor The transfer device 15 has a first load sensor 73 and a second load sensor 75. The first load sensor 73 and the second load sensor 75 are sensors that detect when the load W protrudes from the platform 37 in the second direction (load collapse, protruding). In this embodiment, the first load sensor 73 and the second load sensor 75 are arranged on both sides of the second direction end of the transport vehicle body 3a, and can detect the load W and the pair of side arms 33 (described later). Specifically, the first load sensor 73 is arranged at one second direction end of the transport vehicle body 3A, and the second load sensor 75 is arranged at the other second direction end of the transport vehicle body 3A (see FIG. 8).
The first load sensor 73 is a transmission type photoelectric sensor, and is composed of a light-emitter 73a that emits light and a light-receiver 73b that detects the light emitted from the light-emitter 73a. That is, the light-emitter 73a and the light-receiver 73b are paired. The light-emitter 73a emits light parallel to the first direction. That is, when the light-receiver 73b does not receive the light emitted from the light-emitter 73a, it means that an object is present between the light-emitter 73a and the light-receiver 73b. Also, when the light-receiver 73b receives the light emitted from the corresponding light-emitter 73a, it means that no object is present between the light-emitter 73a and the light-receiver 73b.
Similarly, the second load sensor 75 is composed of a light projector 75a that emits light and a light receiver 75b that detects the light emitted from the light projector 75a.
4, the first load sensor 73 and the second load sensor 75 are provided at positions to detect the portion below the hooks 33b of the pair of side arms 33. More specifically, the first load sensor 73 and the second load sensor 75 are provided below the lower ends of the hooks 33b and above the lower ends of the pair of side arms 33. Therefore, the opening and closing of the hooks 33b does not affect the detection result.

(5) Lifting Device The storage lifting device 11 is disposed between the rack 1 and the storage station 7, and has a lifting mechanism (not shown) and a lifting platform 53. The lifting mechanism is a known technology, and raises and lowers the lifting platform 53 in the vertical direction along the support pillars 55. The lifting platform 53 has a lifting platform conveyor 57 that transfers the cargo W between the storage station 7 and the shelf 21.
In addition, each shelf 21 is provided with an entrance conveyor 23 at a portion adjacent to the entrance lift device 11 in the first direction. Therefore, both conveyors operate in conjunction with each other to transfer the luggage W. The entrance conveyor 23 functions as a buffer conveyor for storing luggage.

The outgoing lifting device 13 is provided on the same side of the rack 1 as the incoming lifting device 11 in the first direction. The outgoing lifting device 13 is disposed between the rack 1 and the outgoing station 9, and has a lifting mechanism (not shown) and a lifting platform 63. The lifting mechanism is a known technology, and raises and lowers the lifting platform 63 in the vertical direction along a support (not shown). The lifting platform 63 has a lifting platform conveyor 67 that transfers the baggage W between the outgoing station 9 and the shelf 21.
In addition, an outgoing conveyor 25 is provided on each shelf 21 at a portion adjacent to the outgoing lifting device 13 in the first direction. Therefore, both conveyors operate in conjunction with each other to deliver the luggage W. The outgoing conveyor 25 functions as a buffer conveyor for storing luggage.

(6) Storage Station and Delivery Station The storage station 7 is disposed on one side of the rack 1 in the first direction. The storage station 7 receives the baggage W to be stored in the rack 1 from a carry-in conveyor (not shown). The storage station 7 has a station conveyor 7a.

The outgoing station 9 is disposed on the same side as the receiving station 7 in the first direction with respect to the rack 1. The outgoing station 9 receives the baggage W taken out from the rack 1. The receiving station 7 has a station conveyor 9a.
The locations and number of the entrance and exit stations are not particularly limited.

(7) Control Configuration of the Automated Warehouse The control configuration of the automated warehouse 100 will be described with reference to Fig. 5. Fig. 5 is a functional block diagram showing the control configuration of the automated warehouse.
As shown in FIG. 5, the automated warehouse 100 has a controller 51 .
The controller 51 is a device that manages the storage and the entry and exit of the luggage W in the automated warehouse 100. The controller 51 is a computer system having a processor (e.g., a CPU), a storage device (e.g., a ROM, a RAM, a HDD, an SSD, etc.), and various interfaces (e.g., an A/D converter, a D/A converter, a communication interface, etc.).
The controller 51 is a ground controller that receives commands such as storage and retrieval from a higher-level controller (not shown) and reports the results of execution. The controller 51 may be realized by a plurality of computers distributed among the units 4.

The controller 51 may perform various control operations by executing a program stored in a memory unit (corresponding to part or all of the memory area of a storage device), or some of the control operations may be realized by hardware included in the controller 51.
The controller 51 is connected to the entrance lift device 11, the exit lift device 13, the entrance station 7, the exit station 9, the plurality of transport vehicles 3, the plurality of entrance conveyors 23, and the plurality of exit conveyors 25. The controller 51 is capable of controlling these devices.

Although not shown, the controller 51 is connected to sensors that detect the size, shape, and position of the luggage W, sensors and switches that detect the status of each device, and an information input device.

(8) Control Configuration of the Transport Vehicle The control configuration of the transport vehicle 3 will be described with reference to Fig. 6. Fig. 6 is a functional block diagram showing the control configuration of the transport vehicle.
The controller 51 has a non-detection confirmation unit 81, a one-side movement unit 83, a one-side position memory unit 85, an other-side movement unit 87, a movement amount determination unit 89, a half-movement amount movement unit 91, and a center position memory unit 93 in order to grasp the center position in the transfer direction of the pair of side arms 33.

The non-detection confirmation unit 81 confirms that the pair of side arms 33 are not detected by the first load sensor 73 and the second load sensor 75 .
The one-way moving section 83 moves the pair of side arms 33 in one of the transfer directions until one of the first load sensor 73 and the second load sensor 75 detects the load.

The one-side position memory unit 85 stores the value of the arm movement amount detection sensor 71 when one of the pair of side arms 33 is detected by the first load sensor 73 or the second load sensor 75. Specifically, the value of the encoder of the transfer motor 43 is stored. Note that, as a modified example, "storing the value of the arm movement amount detection sensor" also includes presetting the value of the arm movement amount detection sensor (i.e., setting it to 0). In this case, the value of the encoder is set to 0 and a new count is started.
The other-side moving section 87 moves the pair of side arms 33 in the other direction in the transfer direction until the other of the first load sensor 73 and the second load sensor 75 is detected.

The movement amount grasping unit 89 grasps the movement amount between the detection positions from the value of the arm movement amount detection sensor 71 when the other of the first load sensor 73 and the second load sensor 75 detects the pair of side arms 33 and the value of the arm movement amount detection sensor 71 stored in the one position memory unit 85. Specifically, the movement amount grasping unit 89 calculates the movement amount between the detection positions by subtracting the encoder value when the pair of side arms 33 are detected on one side from the encoder value when the pair of side arms 33 are detected on the other side. Note that in a modified example in which the value of the arm movement amount detection sensor is preset (i.e., set to 0), the count value (encoder value) itself after resetting to 0 is grasped as the movement amount between the detection positions.

The half-movement amount moving unit 91 moves the pair of side arms 33 in one direction by half the amount of movement between the detection positions.
The center position storage unit 93 stores the value of the arm movement amount detection sensor 71 when the arm has moved halfway as the center position.

The controller 51 further has an arm advance direction detection unit 95. The arm advance direction detection unit 95 determines the direction in which the pair of side arms 33 are advancing based on the detection results of the first load sensor 73 and the second load sensor 75. Therefore, the direction in which the pair of side arms 33 are advancing can also be detected using the first load sensor 73 and the second load sensor 75.

The controller 51 further includes an object determination unit 97. When the first load sensor 73 and the second load sensor 75 detect an object, the object determination unit 97 determines whether the luggage W is protruding or whether the pair of side arms 33 are advanced. Therefore, the detection results of the first load sensor 73 and the second load sensor 75 can be accurately grasped.

(9) Storage and Delivery Operations in the Automated Warehouse (9-1) Storage Operation First, the lift platform conveyor 57 of the lift platform 53 of the storage lift device 11 moves to the position of the station conveyor 7a of the storage station 7.

Next, the station conveyor 7a transports the luggage W to the lift platform conveyor 57 of the storage lift device 11.
Next, the lift platform 53 is lifted to a position corresponding to the shelf 21 on which it has been determined that the cargo W will be stored.
Next, the lift platform conveyor 57 of the lift platform 53 transports the baggage W to the storage conveyor 23.

Next, the transport vehicle 3 moves to the storage conveyor 23, and the transfer device 15 loads the luggage W onto it.
Finally, the transport vehicle 3 travels in the first direction, and the transfer device 15 lowers the luggage W into the target opening 22 of the shelf 21.

(9-2) Unloading Operation First, the transport vehicle 3 travels in the first direction to the front of the target entrance 22 where the cargo W on the shelf 21 is located, and the transfer device 15 loads the cargo W.
Next, the transport vehicle 3 moves to the outgoing conveyor 25, and the transfer device 15 unloads the luggage W.
Next, the lift platform 63 of the unloading lift device 13 is lifted up to a position corresponding to the shelf level 21 from which it has been determined that the luggage W will be unloaded.

Next, the outgoing conveyor 25 transports the luggage W to the lifting platform conveyor 67 of the lifting platform 63 of the outgoing lifting device 13.
Next, the lift platform 63 is raised and lowered to the position of the station conveyor 9 a of the outgoing station 9 .
Finally, the platform conveyor 67 of the platform 63 transports the baggage W to the station conveyor 9a of the outgoing station 9.

(10) Control operation for setting the origin position in the transfer direction The control operation for setting the origin position in the transfer direction will be described with reference to Fig. 7 to Fig. 11. Fig. 7 is a flowchart showing the control operation for setting the origin position in the transfer direction. Figs. 8 to 11 are schematic diagrams showing an example of the transfer direction positions of a pair of side arms during the control operation for setting the origin position in the transfer direction.

The control flow charts described below are merely examples, and each step may be omitted or replaced as necessary. In addition, a plurality of steps may be executed simultaneously, or some or all of the steps may be executed in an overlapping manner.
Furthermore, each block in the control flowchart is not limited to a single control operation, but can be replaced with a plurality of control operations represented by a plurality of blocks.
The operation of each device is the result of commands from the controller 51 to the device, and these are represented by steps of a software application.

In this transport vehicle 3, for example, the origin position in the transfer direction immediately after power is turned on is set in the following procedure.
In step S1, it is determined whether an object is detected by either the first load sensor 73 or the second load sensor 75. Specifically, the non-detection confirmation unit 81 makes this determination. If the result is Yes, the process proceeds to step S11, and if the result is No (if the non-detection confirmation unit 81 confirms that an object is not detected by the first load sensor 73 or the second load sensor 75), the process proceeds to step S2. In addition, in FIG. 8, the pair of side arms 33 are located near the center in the second direction (arrow X).
In step S2, the pair of side arms 33 are moved in one direction in the second direction. Specifically, the one-way movement unit 83 controls the transfer motor 43 to move the side arms 33. In Fig. 9, the pair of side arms are moved in the second direction toward the upper side of the figure (toward the second load sensor 75).
In step S3, it is determined whether the pair of side arms is detected by one of the first load sensor 73 and the second load sensor 75 (in FIG. 9, the second load sensor 75). If Yes, the process proceeds to step S4, and if No, the process returns to step S2.

In step S4, the value of the arm movement amount detection sensor 71 when one of the first load sensor 73 and the second load sensor 75 (the second load sensor 75 in FIG. 9) detects the pair of side arms 33 is stored. Specifically, the one-position storage unit 85 executes the above operation. The movement of the pair of side arms 33 is also stopped.
In step S5, the pair of side arms 33 are moved to the other side in the second direction. Specifically, the other side moving unit 87 executes the above operation by controlling the transfer motor 43. In Fig. 10, the pair of side arms 33 are moved to the lower side in the second direction (towards the first load sensor 73).
In step S6, it is determined whether or not the pair of side arms 33 has been detected by the other of the first load sensor 73 and the second load sensor 75 (the first load sensor 73 in FIG. 10). Specifically, the controller 51 makes this determination. If the determination is Yes, the process proceeds to step S7, and if the determination is No, the process returns to step S5.

In step S7, the value of the arm movement amount detection sensor 71 when the other of the first load sensor 73 and the second load sensor 75 (first load sensor 73 in FIG. 10) detects the pair of side arms 33 is stored in the other position memory unit 86. In addition, the movement of the pair of side arms 33 is also stopped.
In step S8, the amount of movement between the detection positions (for example, distance D in FIG. 10) is grasped from the value of the arm movement amount detection sensor 71 stored in the other-side position memory unit 86 (step S7) and the value of the arm movement amount detection sensor 71 stored in the one-side position memory unit 85 (step S4). Specifically, the movement amount grasping unit 89 executes the above calculation.

In step S9, the pair of side arms 33 are moved in one direction by half the amount of movement between the detection positions (for example, 1/2 of the above-mentioned distance D). Specifically, the half-movement amount moving unit 91 executes the above operation by controlling the transfer motor 43. Note that in FIG. 11, the pair of side arms 33 are positioned at the center in the second direction (arrow X) as a result of the above movement.
In step S10, the value of the arm movement amount detection sensor 71 when the arm has moved halfway is stored as the center position. Specifically, the center position storage unit 93 executes the above operation.
In step S11, a detected object determination control operation is carried out (described later).

In this transport vehicle 3, the center position (origin) in the transfer direction of the pair of side arms 33 can be grasped by using the first load sensor 73 and the second load sensor 75, and there is no need to provide a dedicated sensor. In other words, the origin sensor and slide area sensor can be eliminated, and the cost of the machine can be reduced. Furthermore, by reducing the number of sensors, the number of adjustment steps and the number of inspection items before shipping can be reduced, and the total cost can be reduced.
As described above, in the transport vehicle 3, the pair of side arms 33 of the transfer device 15 mounted on the transport vehicle 3 can be set to the origin with a simple configuration.

(11) Detected object determination control operation The detected object determination control operation will be described with reference to Fig. 12 to Fig. 16. Fig. 12 is a flowchart showing the detected object determination control operation. Figs. 13 to 16 are schematic diagrams showing an example of the transfer direction positions of a pair of side arms during the detected object determination control operation.
In step S31, it is determined in which direction the detected object advances in the second direction based on the detection results of the first load sensor 73 and the second load sensor 75. Specifically, the arm advance direction detection unit 95 executes the determination. For example, in Fig. 13 and Fig. 15, the second load sensor 75 detects an object, and it is determined that the detected object is on the upper side of the figure in the second direction. Note that in Fig. 13, the baggage W is detected by the second load sensor 75, and in Fig. 15, the pair of side arms 33 are detected by the second load sensor 75.

In step S32, the hooks 33b of the pair of side arms 33 are opened (moved to the disengaged position). Specifically, the controller 51 controls the hook motor 45 to execute the above operation.
In step S33, the pair of side arms 33 are moved in the direction opposite to the object detection direction of the second direction. Specifically, the controller 51 controls the transfer motor 43 to execute the above operation. In Fig. 14, the pair of side arms 33 are moved from the state of Fig. 13 toward the second load sensor 75. In Fig. 16, the pair of side arms 33 are moved from the state of Fig. 15 toward the second load sensor 75.

In step S34, the process waits for the pair of side arms 33 to be detected by the other of the first load sensor 73 and the second load sensor 75 (in this embodiment, the second load sensor 75). Specifically, the arm advance direction detection unit 95 executes the above determination.
In step S35, the movement of the pair of side arms 33 is stopped. Specifically, the controller 51 causes the transfer motor 43 to execute the above-mentioned operation.

In step S36, it is determined whether an object has been detected by the first load sensor 73 or the second load sensor 75, whichever detects the object first (in this embodiment, the second load sensor 75). Specifically, the object determination unit 97 executes the above determination. If the result is Yes, the process proceeds to step S37, and if the result is No, the process proceeds to step S38.
In step S37, it is determined that an object has been caught. The reason is that an object has been detected again by the first object-catching sensor 73 even though the pair of side arms 33 have moved in opposite directions as shown in Fig. 14. Specifically, the object judging unit 97 executes the above judgment.

In step S38, it is determined that the pair of side arms 33 was on one side of the second direction. The reason is that, as shown in FIG. 16, the pair of side arms 33 moved in the opposite direction, and the object was no longer detected by the second load sensor 75. Specifically, the object determination unit 97 performs the above determination.

2. Features of the embodiment The above embodiment can also be explained as follows.
The transport vehicle 3 (an example of a transport vehicle) is equipped with a transport vehicle body 3a, a transfer device 15, an arm movement amount detection sensor 71, a first load sensor 73, a second load sensor 75, and a controller 51.
The transfer device 15 (an example of an arm-type transfer device) is a device for transferring luggage W between the transport vehicle body 3a (an example of a transport vehicle body) and other devices, and has a pair of side arms 33 (an example of an arm) and a transfer motor 43 (an example of a forward/backward drive motor) for moving the arm forward and backward in both transfer directions. The transfer device 15 is mounted on the transport vehicle body 3a.
The arm movement amount detection sensor 71 (an example of an arm movement amount detection sensor) detects the amount of advancement and retreat of the pair of side arms 33 .
The first load sensor 73 and the second load sensor 75 (an example of a load sensor) are arranged on both sides of the second direction (an example of a transfer direction) end of the transport vehicle main body 3a and are capable of detecting luggage W and a pair of side arms 33.
The controller 51 has a non-detection confirmation unit 81, a one-side movement unit 83, a one-side position memory unit 85, an other-side movement unit 87, a movement amount determination unit 89, a half-movement amount movement unit 91, and a center position memory unit 93 in order to grasp the center position in the transfer direction of the pair of side arms 33.
The non-detection confirmation unit 81 (an example of a non-detection confirmation means) confirms that the pair of side arms 33 are not detected by the first load sensor 73 and the second load sensor 75 .
The one-side movement section 83 (an example of one-side movement means) moves the pair of side arms 33 in one direction in the transfer direction until one of the first load sensor 73 and the second load sensor 75 detects it.
The one-side position memory unit 85 (an example of one-side position memory means) stores the value of the arm movement amount detection sensor 71 when one of the first load sensor 73 and the second load sensor 75 detects the pair of side arms 33.
The other side moving section 87 (an example of the other side moving means) moves the pair of side arms 33 in the other direction in the transfer direction until the other of the first load sensor 73 and the second load sensor 75 detects it.
The movement amount grasping unit 89 (an example of a movement amount grasping means) grasps the amount of movement between the detection positions from the value of the arm movement amount detection sensor 71 when the other of the first load sensor 73 and the second load sensor 75 detects the pair of side arms 33 and the value of the arm movement amount detection sensor 71 stored in the one position memory unit 85.
The half-movement amount moving unit 91 (an example of a half-movement amount moving means) moves the pair of side arms 33 in one direction by half the amount of movement between the detection positions.
The center position storage unit 93 (an example of a center position storage means) stores the value of the arm movement amount detection sensor 71 when the arm has moved halfway as the center position.
In this transport vehicle 3, the center position (origin) of the side arm 33 in the transfer direction can be grasped by using the first load sensor 73 and the second load sensor 75, and there is no need to provide a dedicated sensor. In other words, the origin sensor and slide area sensor can be eliminated, and the cost of the machine can be reduced. Furthermore, by reducing the number of sensors, the number of adjustment steps and the number of inspection items before shipping can also be reduced, resulting in a reduction in total costs.

3. Other embodiments Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention. In particular, the multiple embodiments and modifications described in this specification can be arbitrarily combined as necessary.
(1) Modification of the Transfer Apparatus The side arm of the transfer apparatus may have a base member, a middle member, and a top member. The base member is provided on the main body. The middle member is slidably held by the base member. The top member is slidably held by the middle member. In this case, for example, the middle member or the top member is the detection target.
The side arm type transfer device of the above embodiment may be of a clamping type in which the luggage is clamped by the arms, or of a type in which the arms are brought close to the luggage and a hook is engaged with an engagement portion of the luggage.
The transfer device may be a slide fork that is slidably mounted in the second direction. In this case, for example, the optical axis of the load sensor is set to be oblique so that the slide fork intercepts the optical axis when it advances.

(2) Modifications of the Transport Vehicle The transport vehicle may be a rail-guided vehicle that runs along rails on the ground or on the ceiling.
The transport vehicle may be a stacker crane.
(3) Modifications of the Arm Movement Amount Detection Sensor The power transmission mechanism of the transfer device may be a rack and pinion mechanism, in which case the arm movement amount detection sensor may be an encoder attached to the pinion.

The present invention can be widely applied to transport vehicles that have a transfer device that extends and retracts an arm to transfer cargo.

1: Rack 3: Transport vehicle 3a: Transport vehicle body 4: Unit 5: Rail 7: Storage station 7a: Station conveyor 8: Step 9: Delivery station 9a: Station conveyor 11: Storage lift device 13: Delivery lift device 15: Transfer device 21: Shelf 22: Opening 22a: First end opening 22b: Second end opening 23: Storage conveyor 25: Delivery conveyor 31: Main body 33: Side arm 33a: Side arm body 33b: Hook 41: Travel motor 43: Transfer motor 45: Hook motor 47: Opening/closing motor 51: Controller 53: Lifting platform 55: Support 57: Lifting platform conveyor 63: Lifting platform 67: Lifting platform conveyor 71: Arm movement amount detection sensor 73 : First load sensor 75 : Second load sensor 81 : Non-detection confirmation unit 83 : One side movement unit 85 : One side position memory unit 86 : Other side position memory unit 87 : Other side movement unit 89 : Movement amount recognition unit 91 : Half movement amount movement unit 93 : Center position memory unit 95 : Arm advance direction detection unit 97 : Object determination unit 100 : Automated warehouse

Claims (4)

A transport vehicle body,
An arm-type transfer device for transferring luggage between the transport vehicle body and another device, the arm-type transfer device having an arm and a forward/backward drive motor for moving the arm forward/backward in both transfer directions, the arm-type transfer device being mounted on the transport vehicle body;
an arm movement amount detection sensor that detects the amount of advancement and retreat of the arm;
A pair of load sensors are arranged on both sides of the end of the transport vehicle body in the transfer direction and are capable of detecting the load and the arm;
A controller that grasps a center position of the arm in a transfer direction,
The controller:
a non-detection confirmation means for confirming that the arm is not detected by the pair of load sensors;
one-way movement means for moving the arm in one direction in a transfer direction until one of the pair of load sensors detects the load;
a one-position storage means for storing a value of the arm movement amount detection sensor when the arm is detected by one of the pair of load sensors;
a second movement means for moving the arm in the other direction of the transfer direction until the other of the pair of load sensors detects the load;
a movement amount determining means for determining an amount of movement between detection positions from a value of the arm movement amount detection sensor when the other of the pair of load sensors detects the arm and the value of the arm movement amount detection sensor stored in the one position storage means;
a half-movement amount moving means for moving the arm toward the one side by an amount half the amount of movement between the detection positions;
and a center position storage means for storing the value of the arm movement amount detection sensor when the arm has moved halfway as a center position.
Transport vehicle. the arms are a pair of side arms, each of which is a rear hook type side arm having a side arm body and a hook rotatably provided on both ends of the side arm body in a transfer direction,
2. The transport vehicle according to claim 1, wherein the load sensor is provided at a position for detecting a portion of the pair of side arms that is located below a hook. The transport vehicle according to claim 1 or 2, wherein the controller further includes an arm advance direction detection means for determining the direction in which the arm is advancing based on the detection result of the load sensor. The transport vehicle according to any one of claims 1 to 3, wherein the controller further has an object determination means for determining whether the luggage is protruding or whether the arm is advanced when the luggage sensor detects an object.