Cargo handling vehicle, cargo handling system and cargo handling program

Abstract

To easily detect abnormality of a distance sensor.SOLUTION: A cargo handling vehicle 20 includes: a laser scanner (distance sensor) 29 mounted on a vehicle body 10; and a control unit 27. The control unit 27 performs measurement by the laser scanner 29 on a floor surface F as a target surface, and determines whether or not the laser scanner 29 is abnormal on the basis of a measurement result acquired by the measurement. Setting the floor surface F a distance of which from the laser scanner 29 is always constant as the target surface, enables an abnormality of the laser scanner 29 to be detected easily.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a cargo handling vehicle, a cargo handling system, and a cargo handling program.

Background Art

[0002] Conventionally, cargo handling vehicles such as automated guided forklifts (AGF) that perform cargo handling operations are known. In this type of cargo handling vehicle, surrounding information is acquired by a mounted distance sensor (external sensor) (see, for example, Patent Document 1). It is useful if an abnormality of the distance sensor can be easily detected.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention has been made in view of the above circumstances, and an object thereof is to easily detect an abnormality of a distance sensor.

Means for Solving the Problems

[0005] The cargo handling vehicle according to the present invention includes a distance sensor mounted on the vehicle body, a measurement unit that measures using the distance sensor with the floor surface as a target surface, and a determination unit that determines whether the distance sensor is abnormal based on the measurement result acquired by the measurement unit. It is provided with.

Effects of the Invention

[0006] According to the present invention, an abnormality of the distance sensor can be easily detected.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0009] [Configuration of Cargo Handling System] FIG. 1 is a diagram showing a cargo handling system 1 according to the present embodiment, and FIG. 2 is a block diagram showing a schematic control configuration of the cargo handling system 1. As shown in these diagrams, the cargo handling system 1 performs predetermined cargo handling operations (operations such as loading and unloading, transporting, stacking, picking, sorting, and aligning loads and associated operations) in a work area by a cargo handling vehicle 20. The cargo handling system 1 is a system including, for example, a WMS (Warehouse Management System), a WES (Warehouse Execution System), a WCS (Warehouse Control System), and the like.

[0010] Specifically, the cargo handling system 1 includes at least one cargo handling vehicle 20, a management server 30, and a charging station 50. The charging station 50 is provided within or around the work area, and the charging facility 51 is installed therein. The charging facility 51 is configured to be electrically connectable to the handling vehicle 20 in a predetermined state, and charges a battery (not shown) mounted on the handling vehicle 20.

[0011] The handling vehicle 20 is a vehicle that performs handling operations, such as a forklift that can travel on the road without using rails or the like. The handling vehicle 20 holds a load or pallet by a pair of left and right forks (handling parts) 12 provided on the vehicle body 10 and performs various handling operations. The handling vehicle 20 of the present embodiment is an automated guided forklift (AGF) that can operate automatically (unattended), and operates based on an operation command or the like from the management server 30.

[0012] Specifically, the handling vehicle 20 includes a vehicle body drive unit 21, a fork drive unit 28, an operation unit 22, a display unit 23, a communication unit 24, a position measurement device 25, a laser scanner 29, a storage unit 26, and a control unit 27.

[0013] The vehicle body drive unit 21 includes a traveling motor and a steering motor (both not shown), which are drive sources for the vehicle body 10 of the handling vehicle 20. The traveling motor drives the drive wheels among the wheels. The steering motor rotates (steers) the steering wheels among the wheels. Each motor is powered by a battery (not shown). Note that the drive source is not limited to a motor, and may be an internal combustion engine or the like.

[0014] The fork drive unit 28 is a drive source for operating a pair of forks 12 protruding forward. The fork drive unit 28 of the present embodiment includes an inclination cylinder, a lifting cylinder, and a reach cylinder (all not shown) that tilt, lift, and extend (stretch) a pair of forks 12 with respect to the vehicle body main body 11. These cylinders are piston cylinders driven by hydraulic pressure (for example, oil pressure). The inclination cylinder tilts the lifting body 13 or the mast 14 that supports a pair of forks 12 in the front-rear direction of the vehicle body. The lifting cylinder raises and lowers the lifting body 13 (see FIG. 4) that holds a pair of forks 12 along the mast 14. The reach cylinder moves a pair of forks 12 forward and backward (substantially perpendicular to the mast 14) with respect to the vehicle body 10 (extends and retracts).

[0015] The operation unit 22 is an operation means for the driver to perform various operations during manned (manual) driving. The operation unit 22 includes, for example, a steering wheel, pedals, levers, various buttons, etc., and outputs an operation signal corresponding to the operation content to the control unit 27. The display unit 23 is, for example, a liquid crystal display, an organic electroluminescence display or other display, and displays various information based on a display signal input from the control unit 27. Note that the display unit 23 may be a touch panel that also serves as a part of the operation unit 22, or may include a speaker capable of voice display (output). The communication unit 24 is a communication device capable of transmitting and receiving various information between the management server 30, other cargo handling vehicles 20, etc.

[0016] The position measuring device 25 measures the position of the cargo handling vehicle 20 itself. The information on the self-position acquired by the position measuring device 25 is transmitted, for example, to the management server 30 and used for the position control of the cargo handling vehicle 20 itself. The specific configuration of the position measuring device 25 is not particularly limited, and for example, it may utilize GNSS (Global Navigation Satellite System), SLAM (Simultaneous Localization and Mapping) technology, indoor positioning (indoor mapping) technology, or other technologies.

[0017] The laser scanner 29 is an example of the distance sensor according to the present invention. By acquiring distance information within a predetermined scan area (measurement area), it detects (senses) objects around the vehicle body and outputs the result to the control unit 27. The laser scanner 29 of the present embodiment is a two-dimensional distance sensor (for example, two-dimensional LiDAR (Laser Imaging Detection and Ranging)) having a planar scan area substantially orthogonal to the left-right direction (vehicle width direction) of the vehicle body 10. The laser scanners 29 are arranged on both left and right sides of the vehicle body 10 and project laterally of the vehicle. The laser scanner 29 of the present embodiment is used to detect the lateral width and left-right position of a front object (for example, the left-right displacement of a load or a pallet, etc.).

[0018] The storage unit 26 is a memory constituted by, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), etc., stores various programs and data, and also functions as a work area for the control unit 27. The storage unit 26 of the present embodiment stores a reference data 261 in addition to a program for executing a sensor abnormality detection process (see FIG. 3) described later. The reference data 261 is data used for abnormality determination of the laser scanner 29. Specifically, the reference data 261 of the present embodiment is data obtained by previously measuring the distance from the laser scanner 29 to the floor surface F below (measurement area S described later) by a healthy laser scanner 29.

[0019] The control unit 27 is constituted by, for example, a CPU (Central Processing Unit), etc., and controls the operations of each part of the material handling vehicle 20. Specifically, the control unit 27 operates each part based on a control command from the management server 30 or the operation content of the operation unit 22, develops a program previously stored in the storage unit 26, and executes various processes in cooperation with the developed program.

[0020] The management server 30 centrally controls the cargo handling system 1 and is configured to be able to control the operation of the cargo handling vehicle 20. The management server 30 may be a personal computer, a smartphone, a tablet terminal, or the like. Specifically, the management server 30 includes an operation unit 31, a display unit 32, a communication unit 34, a storage unit 36, and a control unit 37.

[0021] The operation unit 31 is an operation means for an operator to perform various operations for operating the management server 30, and includes, for example, a pointing device such as a mouse or a keyboard. The display unit 32 is, for example, a liquid crystal display, an organic electroluminescence display, or other displays. The display unit 32 displays various information based on a display signal input from the control unit 37. Further, the display unit 32 may be a touch panel that also serves as at least a part of the operation unit 31. The communication unit 34 is a communication device capable of transmitting and receiving various information to and from each cargo handling vehicle 20.

[0022] The storage unit 36 is a memory constituted by, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), etc., stores various programs and data, and also functions as a working area for the control unit 37. The control unit 37 is constituted by, for example, a CPU (Central Processing Unit), etc., and controls the operation of each part of the management server 30. Specifically, the control unit 37 expands a program prestored in the storage unit 36 based on the operation content of the operation unit 31, etc., and executes various processes in cooperation with the expanded program.

[0023] [Sensor Abnormality Detection Process] Subsequently, the sensor abnormality detection process in which the cargo handling system 1 (cargo handling vehicle 20) detects an abnormality of the laser scanner 29 will be described. FIG. 3 is a flowchart showing the flow of the sensor abnormality detection process, and FIG. 4 is a diagram for explaining the sensor abnormality detection process.

[0024] The sensor abnormality detection process is a process executed when the material handling vehicle 20 detects an abnormality in the laser scanner 29. This sensor abnormality detection process is executed by the control unit 27 of the material handling vehicle 20 reading out and expanding the corresponding program from the storage unit 26. The program may be a part of the material handling program executed for a predetermined material handling operation.

[0025] As shown in FIG. 3, first, the control unit 27 executes a predetermined material handling operation in the work area based on a command from the management server 30 (step S1). In the material handling operation, for example, the management server 30 designates specific coordinates to the material handling vehicle 20 and causes the vehicle to carry out loading and unloading to the specified position. When there is no work due to completion of work or the like, the management server 30 moves the material handling vehicle 20 to a standby station (including the charging station 50). Alternatively, the material handling vehicle 20 may autonomously move to the standby station when there is no conveyance instruction.

[0026] Next, the control unit 27 determines whether the material handling vehicle 20 has stopped at a predetermined charging position in the charging station 50 (step S2). That is, here it is determined whether battery charging is being performed. By detecting that charging has started, it may be determined that the vehicle has stopped at the charging position. When it is determined that the material handling vehicle 20 has not stopped at the charging position (step S2; No), the control unit 27 transfers the process to step S1 described above and continues the material handling operation.

[0027] In step S2, when it is determined that the material handling vehicle 20 has stopped at the charging position (step S2; Yes), the control unit 27 performs measurement by the laser scanner 29 with the floor surface F, which is the running surface, as the target surface (step S3). Specifically, as shown in FIG. 4, the control unit 27 irradiates a measurement light beam within a predetermined angular range from each laser scanner 29 toward the lower measurement area S (the dotted portion in the figure), and measures the distance from the laser scanner 29 to the measurement area S. The measurement area S is a portion of the floor surface F that is located below the laser scanner 29 when the handling vehicle 20 stops at a predetermined position with respect to the charging facility 51 for battery charging. Note that the measurement area S may be indicated as a portion used for inspection by painting its inside or edges so that no load or the like is placed thereon. The state of the surface of the measurement area S is not particularly limited as long as it can reproduce the state at the time of measurement of the reference data 261.

[0028] Next, the control unit 27 determines whether the laser scanner 29 is abnormal based on the measurement result obtained in step S3 (step S4). In the present embodiment, the control unit 27 calculates the distance from the laser scanner 29 to the measurement area S based on the measurement result obtained in step S3. Then, the calculated distance is compared with the reference data 261 in which the same distance has been previously measured by a healthy laser scanner 29. Here, the measured value and the reference data 261 are individually compared for each measurement direction (measurement angle) viewed from the laser scanner 29, and if all the differences are within a predetermined value, it is determined that there is no abnormality, and if any exceeds the predetermined value, it is determined that there is an abnormality. However, the determination method is not limited to one using distance information, and for example, information related to at least one of the distance and the light amount may be acquired to perform an abnormality determination. Thereby, an abnormality of the laser scanner 29 can be detected. In particular, an abnormality due to external factors such as dirt, deterioration, adhesion of water droplets, or influence of surrounding dust on the light emitting surface or the light receiving surface can be preferably detected. When it is determined that the laser scanner 29 is not abnormal (step S4; No), the control unit 27 proceeds to step S6 described later.

[0029] On the other hand, in step S4, when it is determined that the laser scanner 29 is abnormal (step S4; Yes), the control unit 27 performs a warning output to warn that an abnormality has occurred in the laser scanner 29 (step S5). Here, the control unit 27 stops the vehicle body 10 and then causes the display unit 23 to display a warning or outputs a warning sound to notify the surrounding workers and the management server 30 that there may be an abnormality in the laser scanner 29. The output (notification) mode in this case is not particularly limited, and for example, a rotating light may be lit. At this time, after the control unit 27 temporarily stops the vehicle body 10 and performs a warning output, it waits for the operator (human) to take action. If the operator checks and determines that there is no abnormality, the temporary stop is manually released and the cargo handling operation is continued.

[0030] Next, the control unit 27 determines whether to end the sensor abnormality detection process (step S6). If it is determined not to end (step S6; No), the process proceeds to step S1 described above to continue the cargo handling operation. On the other hand, for example, if it is determined to end the sensor abnormality detection process for reasons such as completion of a predetermined cargo handling operation (step S6; Yes), the control unit 27 ends the sensor abnormality detection process.

[0031] [Technical Effects of the Present Embodiment] As described above, according to the present embodiment, the floor surface F is measured with the laser scanner 29 (distance sensor) mounted on the vehicle body 10 as the target surface, and based on the measurement result, it is determined whether the laser scanner 29 is abnormal. In this way, by using the floor surface F, whose distance from the laser scanner 29 is always constant, as the target surface, the abnormality of the laser scanner 29 can be easily detected. As a result, even an inexpensive sensor without self-diagnosis (abnormality detection) can be suitably applied as the laser scanner 29, and its abnormality can be detected.

[0032] Further, according to the present embodiment, when the cargo handling vehicle 20 is waiting at the charging station 50, it is determined whether the laser scanner 29 is abnormal. Thereby, every time the cargo handling vehicle 20 returns to battery charging, the abnormality detection of the laser scanner 29 can be automatically executed. In addition, since the abnormality detection is executed when the cargo handling vehicle 20 takes a predetermined position and posture with respect to the charging facility 51, the measurement area S of the floor surface F, which is the target surface, can be specified. Therefore, it is easy to keep the measurement area S in a sound state, and thus the abnormality detection can be suitably executed.

[0033] [Others] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above embodiments (including modified examples).

[0034] For example, in the above embodiment, as an example of the distance sensor according to the present invention, the laser scanner 29 mounted on the side portion of the vehicle body 10 is illustrated. However, the distance sensor according to the present invention is not particularly limited as long as it is mounted on the vehicle body 10 and can measure the distance to the floor surface F. For example, as shown in FIG. 5, the distance sensor according to the present invention may be a fork base end sensor 29A mounted on the base end of the fork 12. The fork base end sensor 29A is used, for example, for detecting a hole portion (fork pocket) of a pallet into which the fork 12 is inserted. The fork base end sensor 29A has a planar measurement area orthogonal to the vertical direction perpendicular to the fork 12, is disposed at the same height as the fork 12, and moves integrally with the fork 12. In this case, the control unit 27 may measure the distance between the fork base end sensor 29A and the floor surface F with the floor surface F (measurement area S) in front as the target surface in a state where the fork 12 is tilted forward. Depending on the type of distance sensor, not only the floor surface, but also the wall surface, a specific structure (such as a part of a pillar of a shelf, etc.), or a part of the vehicle body of another handling vehicle may be used as the measurement target surface. When the management server 30 operates the handling system 1, when the handling vehicle 20 moves to a designated position and stops, anything existing around it can be suitably used as the above-mentioned measurement target surface. That is, in terms of the operation of the system, since it is agreed that the handling vehicle 20 stops at a specific place, abnormal detection can always be performed using the same measurement target surface.

[0035] In addition, in the above embodiment, the abnormal detection of the laser scanner 29 is executed at the charging station 50. However, the abnormal detection of the laser scanner 29 may be executed with the floor surface F as the target surface, and the location and timing are not particularly limited. For example, it may be executed when waiting at a predetermined waiting station other than the charging station 50 (when the vehicle has not received a conveyance instruction), or may be executed during traveling.

[0036] In addition, in the above embodiment, the control unit 27 mounted on the handling vehicle 20 performs various calculations and the like. However, a control means provided outside the handling vehicle 20 (for example, the management server 30) may perform calculations based on the information transmitted from the handling vehicle 20 and transmit the result to the handling vehicle 20. Also, the handling vehicle 20 and the management server 30 may cooperate in various ways to perform various controls.

[0037] In addition, in the above embodiment, the handling vehicle 20 is an unmanned vehicle (unmanned forklift) that can operate without a driver. However, the handling vehicle according to the present invention includes those that can be manned (including remote operation), those that can switch between manned and unmanned operation, and can also be used as an assist function for manned operation. In addition, the handling vehicle according to the present invention is not limited to a forklift as long as it can hold a load with a fork (or something similar) and travel, and includes, for example, an automated guided vehicle (AGV) that travels without a driver. In addition, the details shown in the above embodiments can be appropriately changed without departing from the gist of the invention.

Description of Reference Numerals

[0038] 1 Cargo handling system 10 Vehicle body 12 Fork 20 Cargo handling vehicle 23 Display unit 26 Storage unit 261 Reference data (reference value) 27 Control unit (measurement unit, determination unit) 29 Laser scanner (distance sensor) 29A Fork base end sensor (distance sensor) 30 Management server (management unit) 50 Charging station F Floor surface S Measurement area (measurement range)

Claims

1. A distance sensor mounted on a vehicle body, A measurement unit that measures the floor surface as a target surface using the distance sensor, A determination unit that determines whether the distance sensor is abnormal based on the measurement result obtained by the measurement unit, A material handling vehicle comprising the above.

2. The measurement unit performs measurement over a predetermined measurement range on the floor surface, The determination unit determines that the distance sensor is not abnormal when the difference between the measurement result obtained by the measurement unit and a reference value obtained in advance is within the allowable range in all of the measurement ranges. The material handling vehicle according to Claim 1.

3. The distance sensor is an optical sensor, The measurement unit acquires information related to at least one of distance and light quantity. The material handling vehicle according to Claim 1.

4. The distance sensor has a planar measurement area orthogonal to the plane perpendicular to the left-right direction of the vehicle body and is disposed on the side portion of the vehicle body, The measurement unit measures the distance between the distance sensor and the floor surface below it. The material handling vehicle according to Claim 1.

5. The vehicle body includes a fork that protrudes forward and can tilt forward and backward, The distance sensor has a planar measurement area orthogonal to the vertical direction perpendicular to the fork and is disposed at the same height as the fork, The measurement unit measures the distance between the distance sensor and the floor surface in front with the fork tilted forward as the target surface. The material handling vehicle according to Claim 1.

6. A material handling system comprising the material handling vehicle according to Claim 1 and a management unit capable of communicating with the material handling vehicle, The material handling vehicle is an unmanned vehicle capable of operating unmanned, The management unit causes the distance sensor to be determined whether it is abnormal when the material handling vehicle is waiting at a predetermined standby position. Material handling system.

7. A computer of a material handling vehicle including a vehicle body and a distance sensor mounted on the vehicle body, A measurement unit that measures the floor surface as a target surface using the distance sensor, A determination unit that determines whether the distance sensor is abnormal based on the measurement result obtained by the measurement unit, A material handling program that functions as such.

Images