Unmanned cargo handling vehicles and cargo handling systems for refrigerated warehouses

Abstract

To provide an unmanned cargo handling vehicle capable of travelling safely while minimizing the detection of fog as an obstacle in a specific section where fog forms, and to provide a cargo handling system for freezing warehouse.SOLUTION: An unmanned fork lift 3 includes: a vehicle body 3A travelling in a specific section where fog forms; a laser sensor 33A and an ultrasonic sensor 33B for detecting an obstacle which hinders the travel of the vehicle body 3A; and a control device for controlling the travel of the vehicle body 3A based on the detection result of the obstacle. The control device controls the travel of the vehicle body 3A based on the obstacle detection result by the laser sensor 33A when the vehicle body 3A is travelling in a section other than the specific section, and when the vehicle body 3A is travelling in the specific section, it restricts the travel speed of the vehicle body 3A compared with the time when the vehicle body 3A is travelling in the section other than the specific section, and controls the travel of the vehicle body 3A based on the obstacle detection result by the ultrasonic sensor 33B.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an unmanned loading and unloading vehicle that performs loading and unloading operations inside and outside a freezer and a loading and unloading system for a refrigerated warehouse. [Background technology]

[0002] In order to reduce the burden on workers in low-temperature environments, unmanned cargo handling vehicles have been developed that perform cargo handling tasks such as loading and unloading and transporting cargo inside and outside freezers (see, for example, Patent Document 1). In general, unmanned cargo handling vehicles are equipped with obstacle sensors that detect obstacles that impede travel, and it is known that reflective laser sensors, for example, are used as obstacle sensors.

[0003] However, fog may occur near the entrance and exit of the freezer, and the laser sensor may erroneously detect the fog as an obstacle, causing the unmanned loading and unloading vehicle to stop traveling to avoid contact with the obstacle. Therefore, it is conceivable to prevent the laser sensor from operating in specific sections where fog occurs so that the fog is not detected as an obstacle.

[0004] However, if the laser sensor is configured not to operate in a specific section, if an obstacle is present in that specific section, the obstacle cannot be detected, and there is a risk that the unmanned loading and unloading vehicle will come into contact with the obstacle. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-268895 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide an unmanned loading and unloading vehicle and a loading and unloading system for a refrigerated warehouse that can travel safely while suppressing detection of fog as an obstacle in specific sections where fog occurs. [Means for solving the problem]

[0007] In order to solve the above problems, the unmanned loading and unloading vehicle of the present invention is an unmanned loading and unloading vehicle that performs loading and unloading operations inside and outside a freezer, and comprises a vehicle body that travels in a specific section where fog occurs, a laser sensor and an ultrasonic sensor as obstacle sensors that detect obstacles that impede the travel of the vehicle body, and a control device that controls the travel of the vehicle body based on the detection results of the obstacle, wherein the control device controls the travel of the vehicle body based on the detection results of the obstacle by the laser sensor when the vehicle body is traveling in a section other than the specific section, limits the travel speed of the vehicle body when the vehicle body is traveling in the specific section compared to when the vehicle body is traveling in a section other than the specific section, and controls the travel of the vehicle body based on the detection results of the obstacle by the ultrasonic sensor instead of the laser sensor.

[0008] In addition, it is preferable that the control device starts controlling the traveling of the vehicle body using the ultrasonic sensor instead of the laser sensor, under the condition that the vehicle body is traveling in the specific section and the traveling speed of the vehicle body is less than a predetermined speed.

[0009] It is also preferable that the vehicle further comprises a position information acquisition device that acquires position information of the vehicle body, and the control device determines whether or not the vehicle body is traveling in the specific section based on the position information of the vehicle body.

[0010] In addition, the loading and unloading system for a refrigerated warehouse of the present invention comprises the above-mentioned unmanned loading and unloading vehicle, and a management computer capable of communicating with the unmanned loading and unloading vehicle and transmitting travel section information specifying the travel section of the unmanned loading and unloading vehicle, and it is preferable that the control device determines whether the vehicle body is traveling in the specific section based on the travel section information received from the management computer. Effect of the Invention

[0011] According to the present invention, it is possible to provide an unmanned loading and unloading vehicle and a loading and unloading system for a refrigerated warehouse that can travel safely while suppressing detection of fog as an obstacle in specific sections where fog occurs. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic diagram of a loading / unloading system for a refrigerated warehouse including an unmanned loading / unloading vehicle according to an embodiment of the present invention. [Diagram 2] 2 is a schematic configuration diagram of the unmanned loading and unloading vehicle according to the embodiment. FIG. [Diagram 3] 2 is a block diagram showing a schematic configuration of the unmanned loading and unloading vehicle according to the embodiment; FIG. [Figure 4] 5 is a flowchart showing a flow of a specific section travel process performed by the control device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A cargo handling system S for a refrigerated warehouse according to one embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the cargo handling system S for a refrigerated warehouse includes a refrigerated warehouse 1 including a freezer 1A and a front room 1B, a management computer 2, and an unmanned forklift 3 as an unmanned cargo handling vehicle.

[0014] The freezer warehouse 1 is a warehouse for freezing and storing storage objects N, such as fresh foods and frozen foods. The freezer 1A is a room having storage space for the storage objects N, and has an entrance / exit 11 leading to the front room 1B. The front room 1B is a room for entering and exiting the freezer 1A. The freezer warehouse 1 is equipped with refrigeration and air conditioning equipment (not shown) for maintaining the temperatures in the freezer 1A and the front room 1B at predetermined set temperatures (for example, minus 25°C in the freezer 1A and 2°C in the front room 1B).

[0015] The cold storage warehouse 1 also includes a heat-resistant door 12 and an air curtain 13 provided at the entrance 11 of the freezer 1A. The heat-resistant door 12 closes the entrance 11 to prevent cold air from flowing out from the freezer 1A to the front room 1B, and when the unmanned forklift 3 moves in and out of the freezer 1A, it opens the entrance 11 so that the freezer 1A and the front room 1B communicate with each other. The air curtain 13 blows out air to generate an air current that covers the entrance 11 in order to prevent cold air from flowing out from the freezer 1A to the front room 1B when the entrance 11 is open. When the entrance 11 is open, fog is generated in a specific section A near the entrance 11.

[0016] The management computer 2 is an electronic device capable of communicating with the unmanned forklift 3, and manages the unmanned forklift 3 by transmitting and receiving various information. Specifically, the management computer 2 receives operation information of the unmanned forklift 3, position information of the unmanned forklift 3, and the like from the unmanned forklift 3. The management computer 2 also transmits to the unmanned forklift 3 cargo pick-up operation information for designating a cargo pick-up operation for the unmanned forklift 3, travel section information for designating a travel section for the unmanned forklift 3, cargo deposit operation information for designating a cargo deposit operation for the unmanned forklift 3, and the like. When the unmanned forklift 3 needs to pass through the entrance / exit 11, the management computer 2 transmits travel section information for designating a specific section A as the travel section for the unmanned forklift 3.

[0017] The unmanned forklift 3 is a forklift that performs loading and unloading operations inside and outside the freezer 1A. The unmanned forklift 3 receives loading operation information, travel section information, and loading operation information from the management computer 2, and based on that information, loads the storage object N, transports the storage object N by traveling within the freezer 1, and loads the storage object N.

[0018] 2, the unmanned forklift 3 includes a vehicle body 3A that travels inside and outside the freezer 1A, and a loading device 3B that handles the storage object N. The loading device 3B includes a fork 31A that supports the storage object N, and a lift device 31B that raises and lowers the fork 31A.

[0019] The vehicle body 3A is configured to be capable of moving straight in a vehicle body direction D1 indicated by an arrow D1 and a fork direction D2 indicated by an arrow D2 in Fig. 2. When entering or leaving the freezer 1A, the vehicle body 3A passes through the entrance / exit 11, and thus travels through a specific section A (see Fig. 1) near the entrance / exit 11 where fog occurs. The vehicle body 3A travels in the vehicle body direction D1 at least in the specific section A.

[0020] The unmanned forklift 3 also includes a laser sensor 32, a laser sensor 33A and an ultrasonic sensor 33B serving as obstacle sensors, and a motion sensor 34 (see FIG. 3).

[0021] The laser sensor 32 is a sensor that acquires data for SLAM (Simultaneous Localization and Mapping) by LiDAR (Light Detection and Ranging). The laser sensor 32 is provided on the upper part of the lift device 31B, and projects laser light in all directions of the unmanned forklift 3. The laser sensor 32 receives the laser light reflected by a plurality of reflectors (not shown) and other objects installed in the cold storage warehouse 1. In this way, the laser sensor 32 detects the objects that reflect the laser light, and acquires data related to the positional relationship between the unmanned forklift 3 and surrounding objects.

[0022] The laser sensor 33A is an obstacle sensor that detects an obstacle that impedes the travel of the vehicle body 3A in the vehicle body direction D1 by using LiDAR. The laser sensor 33A is provided at the end of the vehicle body 3A on the vehicle body direction D1 side. The laser sensor 33A projects laser light toward a predetermined area R1 on the vehicle body direction D1 side, and detects the obstacle by receiving the laser light reflected by the obstacle present in the area R1.

[0023] The ultrasonic sensor 33B is an obstacle sensor that detects an obstacle that impedes the travel of the vehicle body 3A in the vehicle body direction D1 by transmitting and receiving ultrasonic waves. The ultrasonic sensor 33B is provided at the end of the vehicle body 3A in the vehicle body direction D1, and in this embodiment, as shown in Fig. 2(A), two ultrasonic sensors 33B are provided at intervals in the width direction of the vehicle body 3A in order to expand the detection range of the obstacle. When the vehicle body 3A travels in a section where the laser sensor 33A cannot detect an obstacle (i.e., a specific section A near the entrance / exit 11 where fog occurs), the ultrasonic sensor 33B transmits ultrasonic waves toward a predetermined area R2 on the vehicle body direction D1 side and receives ultrasonic waves reflected by an obstacle present in the area R2 to detect the obstacle.

[0024] As shown in FIG. 3, the unmanned forklift 3 further includes a motion sensor 34, a position information acquisition device 35, a traveling device 36, and a control device 37.

[0025] The motion sensor 34 is a sensor that obtains data for odometry by detecting the operation of the unmanned forklift 3. Specifically, the motion sensor 34 is configured, for example, by a vehicle speed sensor that detects the vehicle speed, a steering angle sensor that detects the steering angle of the wheels, or an acceleration sensor that detects acceleration, or a combination of a plurality of these sensors.

[0026] The position information acquisition device 35 acquires position information of the vehicle body 3A (i.e., position information of the unmanned forklift 3, which is the vehicle itself). In this embodiment, the position information acquisition device 35 is composed of a laser sensor 32, a motion sensor 34, an environmental map creation device 35A, and a vehicle position estimation device 35B.

[0027] The environmental map creation device 35A creates an environmental map of the inside of the cold storage warehouse 1 based on the data acquired by the laser sensor 32. The environmental map includes information on the surrounding environment of the unmanned forklift 3, and is used to estimate the vehicle position of the unmanned forklift 3.

[0028] The vehicle position estimation device 35B estimates the position of the vehicle body 3A (i.e., the vehicle position of the unmanned forklift 3) based on data acquired by the laser sensor 32 and the motion sensor 34. Specifically, when the vehicle body 3A is traveling in a section other than the specific section A near the entrance / exit 11, the vehicle position estimation device 35B estimates the position of the vehicle body 3A based on data acquired by the laser sensor 32 and the environmental map created by the environmental map creation device 35A. When the vehicle body 3A is traveling in the specific section A near the entrance / exit 11, the vehicle position estimation device 35B estimates the amount of movement of the vehicle body 3A based on data acquired by the motion sensor 34, and estimates the position of the vehicle body 3A based on the estimated amount of movement.

[0029] The traveling device 36 is a device that causes the vehicle body 3A to travel. The traveling device 36 includes an electric motor (not shown) that generates power, a steering device (not shown) that changes the traveling direction of the vehicle body 3A, and a braking device (not shown) that brakes the vehicle body 3A.

[0030] The control device 37 controls the traveling of the vehicle body 3A by controlling the traveling device 36. The control device 37 judges whether the vehicle body 3A is traveling in the specific section A or not based on the traveling section information received from the management computer 2 and the position information of the unmanned forklift 3 (position information of the vehicle body 3A) acquired by the position information acquisition device 35, and the like, and controls the traveling device 36 based on the judgment result.

[0031] Specifically, the control device 37 operates in the SLAM driving control mode when the vehicle body 3A is traveling in a section other than the specific section A, and operates in the odometry driving control mode when the vehicle body 3A is traveling in the specific section A. The control device 37 in the SLAM driving control mode controls the traveling of the vehicle body 3A based on the position information of the vehicle body 3A acquired using the laser sensor 32. On the other hand, the control device 37 in the odometry driving control mode controls the traveling of the vehicle body 3A based on the position information of the vehicle body 3A acquired using the motion sensor 34. The control device 37 operating in the odometry driving control mode controls the traveling of the vehicle body 3A without using the laser sensor 32, and therefore can make the vehicle body 3A travel without being affected by fog occurring in the specific section A.

[0032] The control device 37 also controls the traveling of the vehicle body 3A based on the detection result of the obstacle by the laser sensor 33A and the ultrasonic sensor 33B. Specifically, when the vehicle body 3A is traveling in a section other than the specific section A, the control device 37 controls the traveling of the vehicle body 3A based on the detection result of the obstacle by the laser sensor 33A. When the vehicle body 3A is traveling in the specific section A and the traveling speed of the vehicle body 3A is a predetermined speed (for example, 0.8 km per hour) or more, the control device 37 also controls the traveling of the vehicle body 3A based on the detection result of the obstacle by the laser sensor 33A. In these cases, the control device 37 does not use the ultrasonic sensor 33B, and stops the traveling of the vehicle body 3A when an obstacle is detected by the laser sensor 33A. When the vehicle body 3A is traveling in the specific section A and the traveling speed of the vehicle body 3A is less than the predetermined speed (for example, 0.8 km per hour), the control device 37 controls the traveling of the vehicle body 3A based on the detection result of the obstacle by the ultrasonic sensor 33B. At this time, the control device 37 does not use the laser sensor 33A, and when an obstacle is detected by the ultrasonic sensor 33B, stops the traveling of the vehicle body 3A.

[0033] That is, the laser sensor 33A and the ultrasonic sensor 33B are used differently as shown in the following table depending on whether the vehicle body 3A is traveling in the specific section A or not and whether the traveling speed is equal to or higher than a predetermined speed or not. [Table 1]

[0034] Furthermore, when the vehicle body 3A is traveling in the specific section A, the control device 37 limits the traveling speed of the vehicle body 3A compared to when the vehicle body 3A is traveling in sections other than the specific section A. In other words, the control device 37 prohibits the vehicle body 3A from traveling in the specific section A at a predetermined speed (e.g., 0.8 km / h) or higher, and controls the vehicle body 3A so that the vehicle body 3A travels in the specific section A at a speed less than the predetermined speed.

[0035] The operation flow of the control device 37 when the unmanned forklift 3 moves from inside the freezer 1A through the specific section A to outside the freezer 1A (i.e., inside the front room 1B) will be described with reference to Fig. 4. The operation flow of the control device 37 when the unmanned forklift 3 moves from outside the freezer 1A through the specific section A to inside the freezer 1A is also similar to the operation flow described below.

[0036] As shown in FIG. 4, first, the control device 37 starts to limit the traveling speed of the vehicle body 3A, and decelerates the vehicle body 3A so that the traveling speed in the specific section A is less than a predetermined speed (e.g., 0.8 km / h) before the vehicle body 3A reaches the specific section A (step S1).

[0037] Next, the control device 37 switches from the SLAM driving control mode to the odometry driving control mode based on the fact that the vehicle body 3A has reached the specific section A (step S2). That is, in step S2, the control device 37 stops controlling the driving of the vehicle body 3A using the laser sensor 32 and starts controlling the driving of the vehicle body 3A using the motion sensor 34.

[0038] Next, on condition that the vehicle body 3A is traveling in the specific section A and the traveling speed of the vehicle body 3A is less than a predetermined speed (e.g., 0.8 km / h), the control device 37 stops detecting obstacles using the laser sensor 33A and starts detecting obstacles using the ultrasonic sensor 33B (step S3). That is, in step S3, the control device 37 stops controlling the traveling of the vehicle body 3A using the laser sensor 33A and starts controlling the traveling of the vehicle body 3A using the ultrasonic sensor 33B instead of the laser sensor 33A.

[0039] Next, the control device 37 switches from the odometry driving control mode to the SLAM driving control mode based on the fact that the vehicle body 3A has passed through the specific section A (step S4). That is, in step S4, the control device 37 resumes control of the driving of the vehicle body 3A using the laser sensor 32 that was stopped in step S2.

[0040] Then, the control device 37 releases the restriction on the traveling speed of the vehicle body 3A that was started in step S1 (step S5), and resumes the detection of obstacles by the laser sensor 33A that was stopped in step S3 (step S6). That is, in steps S5 and S6, the control device 37 accelerates the vehicle body 3A, stops the control of the traveling of the vehicle body 3A using the ultrasonic sensor 33B, and resumes the control of the traveling of the vehicle body 3A using the laser sensor 33A that was stopped in step S3.

[0041] The present embodiment provides the following effects. (1) When the vehicle body 3A is traveling in the specific section A, the traveling of the vehicle body 3A is controlled based on the detection result of the obstacle by the ultrasonic sensor 33B instead of the laser sensor 33A. Therefore, it is possible to prevent the fog occurring in the specific section A from being erroneously detected as an obstacle by the laser sensor 33A, and the obstacle existing in the specific section A can be detected by the ultrasonic sensor 33B. In addition, when the vehicle body 3A is traveling in the specific section A, the traveling speed of the vehicle body 3A is limited compared to when the vehicle body 3A is traveling in a section other than the specific section A. Therefore, it is possible to sufficiently reduce the traveling speed of the vehicle body 3A so that the vehicle body 3A can stop traveling before the unmanned forklift 3 comes into contact with the obstacle detected by the ultrasonic sensor 33B. Therefore, the unmanned forklift 3 can safely travel while suppressing the fog from being detected as an obstacle in the specific section A where the fog occurs.

[0042] (2) If the traveling speed of the vehicle body 3A is equal to or higher than a predetermined speed, even if the ultrasonic sensor 33B can detect an obstacle, the vehicle body 3A may not be able to stop traveling before coming into contact with the obstacle. Therefore, on the condition that the traveling speed of the vehicle body 3A is less than the predetermined speed, control of the traveling of the vehicle body 3A using the ultrasonic sensor 33B instead of the laser sensor 33A is started, so that traveling safety can be further improved.

[0043] (3) Based on the position information of the vehicle body 3A acquired by the position information acquisition device 35, it is determined whether or not the vehicle body 3A is traveling in the specific section A. Therefore, the unmanned forklift 3 can switch the obstacle sensor to be used from the laser sensor 33A to the ultrasonic sensor 33B without acquiring position information of the vehicle body 3A from the outside.

[0044] (4) Based on the travel section information transmitted by the management computer 2, it is determined whether or not the vehicle body 3A is traveling in a specific section A. For this reason, the management computer 2 can specify the specific section A where the obstacle sensor to be used is switched from the laser sensor 33A to the ultrasonic sensor 33B.

[0045] The present invention is not limited to the above embodiment, and the above configurations can be modified. For example, the following modifications can be made, or the following modifications can be combined to make the present invention.

[0046] The control device 37 may start limiting the traveling speed of the vehicle body 3A so that the traveling speed in the specific section A is less than a predetermined speed (e.g., 0.8 km / h) after the vehicle body 3A reaches the specific section A. In other words, the limiting of the traveling speed of the vehicle body 3A may be started before traveling in the specific section A or may be started while traveling in the specific section A.

[0047] The unmanned forklift 3 may be configured to store information related to the specific section A in advance and determine whether the vehicle body 3A is traveling through the specific section A without receiving traveling section information from the management computer 2.

[0048] The arrangement and number of the ultrasonic sensors 33B and the operation of the control device 37 may be changed as appropriate as long as they can detect obstacles present in the specific section A. The unmanned forklift 3 may also include, as obstacle sensors, laser sensors and ultrasonic sensors that detect obstacles that impede the travel of the vehicle body 3A in the fork direction D2.

[0049] The present invention may be applied to an unmanned loading and unloading vehicle other than the unmanned forklift 3. That is, the unmanned loading and unloading vehicle may be an unmanned guided vehicle that does not have the forks 31A, or a derivative model of the unmanned forklift 3. [Explanation of symbols]

[0050] 1. Refrigerated Warehouse 1A Freezer 1B Front room 2 Management Computer 3. Unmanned forklifts (unmanned loading and unloading vehicles) 3A Vehicle body 3B Cargo handling equipment 33A Laser sensor (obstacle sensor) 33B Ultrasonic sensor (obstacle sensor) 35 Location information acquisition device 37 Control device A Specific Section S Refrigerated Warehouse Handling System

Claims

1. In unmanned loading and unloading vehicles that handle loading and unloading inside and outside freezers, A vehicle body traveling in a specific section where fog occurs, a position information acquisition device for acquiring position information of the vehicle body; a laser sensor and an ultrasonic sensor serving as obstacle sensors for detecting an obstacle that impedes the travel of the vehicle body; a control device that controls the traveling of the vehicle body based on the detection result of the obstacle, The control device includes: determining whether the vehicle body is traveling in the specific section based on the position information of the vehicle body and travel section information in which a section passing through an entrance / exit of the freezer is specified as a travel section; When the vehicle body is traveling in a section other than the specific section, the travel of the vehicle body is controlled based on a detection result of the obstacle by the laser sensor; When the vehicle body is traveling in the specific section, the traveling speed of the vehicle body is limited compared to when the vehicle body is traveling in a section other than the specific section, and the traveling of the vehicle body is controlled based on the detection result of the obstacle by the ultrasonic sensor instead of the laser sensor. An unmanned loading and unloading vehicle.

2. The control device starts controlling the traveling of the vehicle body using the ultrasonic sensor instead of the laser sensor, on the condition that the vehicle body is traveling in the specific section and the traveling speed of the vehicle body is less than a predetermined speed.

2. The unmanned loading and unloading vehicle according to claim 1 .

3. A laser sensor for SLAM that acquires SLAM data for creating an environmental map and estimating a vehicle's position; A motion sensor that detects the motion of the vehicle to obtain odometry data, When the vehicle body is traveling in a section other than the specific section, the control device controls the traveling of the vehicle body based on position information of the vehicle body acquired using the SLAM laser sensor, and when the vehicle body is traveling in the specific section, controls the traveling of the vehicle body based on position information of the vehicle body acquired using the motion sensor.

2. The unmanned loading and unloading vehicle according to claim 1 .

4. An unmanned loading and unloading vehicle according to any one of claims 1 to 3; A management computer capable of communicating with the unmanned cargo handling vehicle and transmitting the travel section information; The control device determines whether the vehicle body is traveling in the specific section based on the travel section information received from the management computer. A loading and unloading system for a refrigerated warehouse.

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