Loading control system

Abstract

To provide a loading control system capable of avoiding a situation where cargo cannot be loaded due to collision between an object on a loading platform and the cargo, when the cargo is loaded so that a gap with the object on the loading platform is minimized.SOLUTION: A loading control system S comprises a loading point determination unit 22 configured to determine a loading point at which cargo is loaded onto a loading platform of a truck, and a turning route determination unit 23 configured to determine an arcuate turning route by determining a turning travel start point that is connected, by an arc having a predetermined curvature, to a turning travel end point that is the loading point. A forklift 1 performs turning travel from the turning travel start point to the turning travel end point along the turning route determined by the turning route determination unit 23, and loads cargo at the loading point determined by the loading point determination unit 22.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a loading control system that controls the loading of cargo onto a truck bed by a forklift. [Background technology]

[0002] In recent years, due to the worsening labor shortage in the logistics industry, attention has been focused on automating the loading of cargo onto truck beds, which has been considered difficult, and forklifts that can automatically load cargo onto truck beds have been developed (see, for example, Patent Document 1).

[0003] Patent Document 1 describes a forklift that travels close to a truck with a load supported by its forks, and then faces the side of the truck's loading platform. With the body facing the side of the loading platform, this forklift detects the top surface and side panel (gate) of the loading platform with a laser scanner, moves the body forward to a loading point, which is a predetermined distance forward of the side panel, and then operates the forks (reach, lift down, etc.) to load the load onto the loading platform.

[0004] However, in the configuration of Patent Document 1, the forklift travels in a straight line (straight path) to the loading point where the cargo is loaded, so when loading cargo so as to reduce the gap between the object on the loading platform, there are cases where the object on the loading platform collides with the cargo, making it impossible to load the cargo. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-142351 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide a loading control system that can avoid a situation where an object on the loading platform and the luggage collide, making it impossible to load the luggage, when loading luggage so as to reduce the gap between the object and the loading platform. [Means for solving the problem]

[0007] In order to solve the above problems, the loading control system of the present invention is a loading control system that controls the loading of cargo onto the bed of a truck by a forklift, and is characterized by comprising: a loading point determination unit that determines a loading point where the cargo will be loaded onto the bed; a turning route determination unit that determines an arc-shaped turning route by setting the loading point as the turning end point and determining a turning start point that is connected to the turning end point by an arc having a certain curvature; and the forklift turns from the turning start point to the turning end point according to the turning route determined by the turning route determination unit, and loads the cargo at the loading point determined by the loading point determination unit.

[0008] It is also preferable that an external device capable of communicating with the forklift is provided, and that the external device includes the loading point determination unit and the turning route determination unit.

[0009] The vehicle further includes a just-before-turning route determination unit that determines a just-before-turning route that will set the steering angle of the forklift to an angle for turning at the constant curvature when the forklift reaches the turning start point, and the forklift preferably travels to the turning start point according to the just-before-turning route determined by the just-before-turning route determination unit.

[0010] It is also preferable that an external device capable of communicating with the forklift is provided, and that the external device comprises the loading point determination unit, the turning route determination unit, and the immediately before turning route determination unit.

[0011] It is also preferable that the forklift includes a sensor that detects an object located above the loading platform, and the loading point determination unit determines the loading point based on the result of object detection by the sensor. [Effects of the Invention]

[0012] According to the present invention, a loading control system can be provided that can avoid a situation where an object on the loading platform collides with the luggage, making it impossible to load the luggage, when loading luggage so as to reduce the gap between the object on the loading platform and the luggage. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a loading control system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram showing a schematic configuration of a forklift and a server according to the embodiment. [Figure 3] 10 is a flowchart showing the procedure for loading luggage onto the bed of a truck. [Figure 4] 10(A) and 10(B) are plan views illustrating an example of the operation of a forklift when loading luggage. [Figure 5] 10(C) to 10(E) are plan views illustrating an example of the operation of a forklift when loading cargo. [Figure 6] FIG. 10 is a block diagram showing a schematic configuration of a forklift according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0014] As shown in FIG. 1, the loading control system S according to this embodiment is made up of a forklift 1 and a server 2, and controls the loading of cargo N onto a loading platform Tn of a truck T performed by the forklift 1.

[0015] The forklift 1 is a reach forklift truck, and is an AGF (Automated Guided Forklift) that unmannedly transports a load N. The forklift 1 includes a vehicle body 1A and a load handling device 1B.

[0016] The vehicle body 1A is configured to be capable of traveling straight forward and backward, and also capable of turning left and right by changing the steering angle of the steering wheels. The vehicle body 1A includes rear wheels (not shown) that serve as both steering wheels and drive wheels, a traveling device 11A, and a steering device 11B (see FIG. 2).

[0017] The traveling device 11A is composed of a prime mover that rotates the rear wheels, which are drive wheels, and causes the vehicle body 1A to travel by rotating the drive wheels. The steering device 11B controls the steering angle of the rear wheels, which are steerable wheels, and sets the vehicle body 1A to a state where it can travel straight when the steering angle is 0°, and sets the vehicle body 1A to a state where it can turn when the steering angle is an angle other than 0°. In other words, when the forklift 1 travels, the vehicle body 1A travels straight when the steering angle is 0°, and turns when the steering angle is not 0°.

[0018] The cargo handling device 1B is configured to be able to lift cargo N. The cargo handling device 1B includes a fork 12A, a mast 12B, a lift device 13A, and a reach device 13B (see FIG. 2).

[0019] The fork 12A is composed of two claws extending parallel to each other with a gap between them, and extends horizontally to support the load N. The mast 12B is composed of a telescopic mast that can be extended and retracted vertically, and supports the fork 12A.

[0020] The lift device 13A raises and lowers the forks 12A relative to the vehicle body 1A (i.e., moves them vertically). The reach device 13B moves the forks 12A in the front-to-rear direction relative to the vehicle body 1A. The reach device 13B operates independently of the traveling device 11A, and is therefore able to move the forks 12A even when the vehicle body 1A is stationary.

[0021] The server 2 is an external device provided outside the forklift 1, and is a remote control device that remotely controls the forklift 1. The forklift 1 and the server 2 are configured to be able to communicate wirelessly.

[0022] The truck T is a freight vehicle having a wing body, and is provided with a loading platform Tn into which cargo N can be loaded from the left and right sides of the truck T. The loading platform Tn is separated by a cargo compartment wall Ts located above the loading platform Tn, and multiple cargo N are configured to be loaded in order starting from the position closest to the cargo compartment wall Ts.

[0023] 2, in addition to the components of the vehicle body 1A and the cargo handling device 1B, the forklift 1 further includes laser sensors 14A and 14B, a communication device 15, and a control device 16. The server 2 also includes a communication unit 21, a loading point determination unit 22, a turning route determination unit 23, and a pre-turn route determination unit 24.

[0024] The laser sensor 14A is a LiDAR (Light Detection and Ranging) sensor that is configured with a laser scanner for autonomous driving and measures the distance to an object that reflects the laser light by projecting and receiving the laser light. The laser sensor 14A detects objects located around the forklift 1 by projecting laser light all around the forklift 1.

[0025] The laser sensor 14B is configured with a laser scanner for determining the loading point, and is a LiDAR sensor like the laser sensor 14A. The laser sensor 14B detects an object on the loading platform Tn (i.e., an object located above the loading platform Tn) by projecting a laser beam within a preset range. The object on the loading platform Tn is an object that determines the loading point, and for example, if another package N different from the package N supported by the forks 12A is present on the loading platform Tn, it is the other package N, or if no other package N is present on the loading platform Tn, it is the wall surface Ts of the luggage compartment.

[0026] The communication device 15 communicates with the server 2. Specifically, the communication device 15 transmits to the server 2 position information of an object on the loading platform Tn detected by the laser sensor 14B and position information of the end point of straight traveling after detecting the object on the loading platform Tn. The communication device 15 also receives route information of a turning route and a route immediately before the turning, which will be described later, from the server 2.

[0027] The control device 16 controls the traveling device 11A, the steering device 11B, the lift device 13A, the reach device 13B, and the communication device 15. Based on the object detection results from the laser sensor 14A, the control device 16 controls the traveling device 11A and the steering device 11B so that the forklift 1 travels autonomously along a predetermined route. When controlling the steering angle of the forklift 1, the control device 16 controls the steering device 11B by feedforward control and feedback control. The control of the devices 11A, 11B, 13A, 13B, and 15 by the control device 16 will be described later with reference to FIG. 3.

[0028] The communication unit 21 communicates with the forklift 1. Specifically, the communication unit 21 receives position information of an object on the loading platform Tn and position information of the straight-ahead travel end point from the forklift 1. The communication unit 21 also transmits to the forklift 1 route information of the turning route determined by the turning route determination unit 23 and route information of the immediately before turning route determined by the immediately before turning route determination unit 24.

[0029] The loading point determination unit 22 determines a loading point where the cargo N is to be loaded onto the loading platform Tn without the forklift 1 traveling, based on the position information of the object on the loading platform Tn received by the communication unit 21. That is, the loading point determination unit 22 determines the loading point based on the object detection result by the laser sensor 14B.

[0030] The turning route determination unit 23 determines an arc-shaped turning route connecting a turning start point and a turning end point. Specifically, the turning route determination unit 23 determines the turning route by setting the loading point as the turning end point and determining the turning start point connected to the turning end point by an arc having a certain curvature (hereinafter referred to as "curvature κ"). The turning route is preferably an arc having a central angle of 90° or less. Furthermore, the turning route determination unit 23 stores in advance information on the minimum turning radius at which the forklift 1 can turn, and determines an arc having a radius (hereinafter referred to as "radius R") equal to or greater than the minimum turning radius as the turning route. The radius R is the reciprocal of the curvature κ. The route information of the turning route determined by the turning route determination unit 23 is transmitted to the forklift 1 via the communication unit 21. The route information of the turning route includes information on the turning start point, the turning end point, and the turning radius (i.e., radius R).

[0031] The just-before-turn route determination unit 24 determines a just-before-turn route until the forklift 1 reaches the turning route. Specifically, the just-before-turn route determination unit 24 determines a just-before-turn route such that the steering angle (i.e., the angle of the steering wheels) of the forklift 1 is an angle that allows the forklift 1 to turn with a constant curvature κ when the forklift 1 reaches a turning start point. The just-before-turn route is, for example, a route that appropriately combines a straight route and a curved route. In this embodiment, the just-before-turn route determination unit 24 determines the just-before-turn route based on the position information of the straight traveling end point received by the communication unit 21 and the position information of the turning starting point determined by the turning route determination unit 23. Specifically, the just-before-turn route determination unit 24 determines the straight traveling end point as the just-before-turn traveling start point, the turning starting point as the just-before-turn traveling end point, and determines, as the just-before-turn route, a route that provides a steering angle that allows the forklift 1 to turn with a curvature κ when the forklift 1 reaches the just-before-turn traveling end point. The steering angle (hereinafter referred to as "steering angle δ") required to make a turn with curvature κ can be calculated by solving the relational expression "δ = arctan(L κ)" where L is the length of the wheelbase of the forklift 1. Route information of the route immediately before the turn determined by the turning route determination unit 23 is transmitted to the forklift 1 via the communication unit 21. The route information of the route immediately before the turn includes information related to the end point of travel immediately before the turn and other information required to travel along the route immediately before the turn.

[0032] The flow of loading control by the loading control system S will be described with reference to Fig. 3. Note that the series of flows shown in Fig. 3 is based on the premise that the load N is being supported by the forks 12A.

[0033] First, the laser sensor 14B detects an object on the loading platform Tn while the forklift 1 is traveling straight ahead (step S1). When the object on the loading platform Tn is detected, the control device 16 controls the communication device 15 to transmit position information of the object on the loading platform Tn. Furthermore, the control device 16 controls the traveling device 11A to stop the forklift 1 from traveling straight ahead, and after the forklift 1 has stopped traveling, controls the communication device 15 to transmit position information of the current position, which is the end point of straight ahead traveling.

[0034] Next, the loading point determination unit 22 determines a loading point based on the object detection result in step S1 (step S2), and the turning route determination unit 23 determines a turning route based on the loading point determined in step S2 (step S3). Once the turning route is determined by the turning route determination unit 23, the communication unit 21 transmits route information of the turning route, and the communication device 15 receives the route information of the turning route.

[0035] Next, the immediately before turning route determination unit 24 determines a immediately before turning route based on the turning running start point and the straight running end point determined in step S3 (step S4). When the immediately before turning route determination unit 24 determines the immediately before turning route, the communication unit 21 transmits route information of the immediately before turning route, and the communication device 15 receives the route information of the immediately before turning route.

[0036] Next, the control device 16 controls the traveling device 11A and the steering device 11B so that the forklift 1 travels along the immediately before turning route based on the immediately before turning route determined in step S4 (step S5). That is, the control device 16 causes the forklift 1 to travel from the immediately before turning travel start point, which is the end point of straight travel, to the immediately before turning travel end point, which is the start point of turning travel, in accordance with the route information of the immediately before turning route received by the communication device 15. At this time, the control device 16 controls the lift device 13A so that the forks 12A are higher than the platform Tn by the time the forklift 1 reaches the immediately before turning travel end point, and controls the reach device 13B so that the forks 12A move forward.

[0037] Next, the control device 16 controls the traveling device 11A and the steering device 11B so that the forklift 1 turns along the turning route based on the turning route determined in step S3 (step S6). That is, the control device 16 causes the forklift 1 to turn along the turning route from the turning start point, which is the end point of the travel just before the turn, to the turning end point, which is the loading point, in accordance with the route information of the turning route received by the communication device 15.

[0038] Specifically, in step S6, the control device 16 calculates the position error as "e y ” and the attitude error is “e θ " and the predetermined feedback gains derived from the test run are "k1" and "k2." When the steering angle δ of the forklift 1 during turning is "arctan(L·κ)-k1·e y -k2·e θ The steering device 11B is feedback-controlled so that the position error e y is the distance between the reference point of the forklift 1 and the target point, and the posture error e θ is the difference between the azimuth angle of the left and right central axis of the forklift 1 and the target azimuth angle, and the error e y ,e θ can be obtained using the laser sensor 14A. The feedback gains k1 and k2 can be derived from a running test of the forklift 1.

[0039] Then, the control device 16 controls the lift device 13A to lower the forks 12A to load the cargo N onto the loading platform Tn (step S7). When loading of the cargo N is completed in this manner, the control device 16 controls the reach device 13B to move the forks 12A rearward, and controls the traveling device 11A and the steering device 11B to cause the forklift 1 to travel in reverse, thereby withdrawing the forks 12A from the cargo N. That is, at this time, the control device 16 controls the steering device 11B to switch the steering angle of the forklift 1 to 0°.

[0040] An example of the operation of the loading control system S will be described with reference to Figures 4 and 5(A) to (E). The two-dot chain lines in the figures indicate the route traveled by the forklift 1. The outline arrows in the figures indicate the direction in which the forklift 1 is traveling.

[0041] 4(A), the forklift 1 travels straight along the loading platform Tn of the truck T, and the laser sensor 14B detects the loading platform wall surface Ts, which is an object on the loading platform Tn. As a result, the turning route determination unit 23 determines a turning route connecting the turning end point P3 and the turning start point P2.

[0042] Next, as shown in Fig. 4(B), the forklift 1 detects the cargo compartment wall surface Ts and then stops straight ahead after traveling a predetermined distance, so that the just-before-turn route determination unit 24 determines a just-before-turn route connecting the straight ahead traveling end point P1 and the turning traveling start point P2.

[0043] Next, as shown in FIG. 5(C), the forklift 1 travels along the immediately before turning route from a straight traveling end point P1 (a immediately before turning traveling start point) to a turning traveling start point P2 (an immediately before turning traveling end point).

[0044] 5(D), the forklift 1 reaches the turning start point P2 and continues traveling while maintaining a constant steering angle, turning along an arc-shaped turning route from the turning start point P2 to the turning end point P3 (loading point). When the forklift 1 reaches the turning end point P3, it loads the cargo N onto the loading platform Tn while stopping its travel.

[0045] Then, as shown in FIG. 5(E), after completing loading of the cargo N, the forklift 1 sets the steering angle to 0° and travels straight away from the loading platform Tn.

[0046] In this embodiment, the following effects are obtained. (1) The forklift 1 reaches the loading point, which is the end point of the turning travel, by turning along an arc-shaped turning route. Therefore, compared to reaching the loading point by traveling straight along a straight route, the distance between the load N supported by the forks 12A and an object on the loading platform Tn (e.g., the cargo compartment wall Ts or another load N) can be increased while the forklift 1 is traveling, and the allowable path tracking error can be increased. Therefore, when loading the load N so as to reduce the gap with the object on the loading platform Tn, it is possible to avoid a collision between the load N and the object on the loading platform Tn, which would prevent the load N from being loaded. In addition, it is possible to reduce the travel range of the forklift 1 required to load the load N. Furthermore, when the forklift 1 is caused to turn along a non-arcuate turning route, the calculations required for feedforward control tend to be difficult. However, when the forklift 1 is caused to turn along an arcuate turning route with a constant curvature κ, the control device 16 can easily determine the feedback components using the above-described calculation formula, and can also easily determine the feedforward components without being affected by the dynamic characteristics of the steering.

[0047] (2) The forklift 1 travels to the turning start point along a route immediately before the turn, which has a steering angle (i.e., the steering angle of the steering wheels of the forklift 1) that is set to an angle (i.e., steering angle δ) for traveling at a constant curvature κ when the forklift 1 reaches the turning start point. Therefore, when switching from traveling along the route immediately before the turn to traveling along the turning route, it is not necessary for the forklift 1 to stop traveling in order to change the steering angle to δ.

[0048] (3) The server 2, which can communicate with the forklift 1, includes a loading point determination unit 22, a turning route determination unit 23, and a route just before turning determination unit 24. This reduces the burden on the forklift 1 compared to a configuration in which the forklift 1 determines the loading point, turning route, and route just before turning.

[0049] (4) The loading point determination unit 22 determines the loading point based on the object detection result by the laser sensor 14B provided in the forklift 1. This eliminates the need to provide a sensor for determining the loading point on a fixed structure.

[0050] The present invention is not limited to the above-described 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.

[0051] 6, the forklift 1 may include a loading point determination unit 17A, a turning route determination unit 17B, and a just-before-turn route determination unit 17C. The loading point determination unit 17A, the turning route determination unit 17B, and the just-before-turn route determination unit 17C have the same functions as the loading point determination unit 22, the turning route determination unit 23, and the just-before-turn route determination unit 24 of the above embodiment. According to this modification, the forklift 1 can travel to the loading point and load the cargo N without communicating with the server 2.

[0052] The forklift may be provided with a sensor other than the laser sensor 14B as a sensor for detecting an object located above the loading platform Tn. Also, the laser sensor 14A may be configured to also serve as a sensor for detecting an object located above the loading platform Tn.

[0053] The forklift may be an AGF other than a laser-guided type. For example, the forklift may be a gyro-guided AGF equipped with a gyro sensor, and the control device 16 may control the traveling device 11A and the steering device 11B so that the forklift 1 travels along a predetermined route based on the results of estimating the position and attitude of the forklift using the gyro sensor. Alternatively, the forklift may be a magnetic-guided AGF equipped with a magnetic sensor, and the control device 16 may control the traveling device 11A and the steering device 11B so that the forklift 1 travels along a predetermined route based on the results of detection by the magnetic sensor of a magnetic guide laid on the travel path.

[0054] When an object on the loading platform Tn is detected, the control device 16 may control the communication device 15 to transmit position information of the straight travel end point, which is the planned arrival point, while the forklift 1 is traveling straight.

[0055] The forklift is not limited to a reach forklift truck, but may also be a counterbalance forklift truck. The fork configuration may also be changed depending on the load handled by the forklift. For example, instead of the fork 12A consisting of two prongs, the forklift may be equipped with a fork consisting of three or more prongs or a single cylindrical ram. [Explanation of symbols]

[0056] 1 forklift 1A Vehicle body 1B Cargo handling equipment 2 Server (external device) 12A fork 14B Laser sensor (sensor) 17A Loading point determination unit 17B Turning route determination unit 17C Route determination unit just before turning 22 Loading point determination unit 23 Turning route determination unit 24 Route determination unit just before turning N Luggage P1 End point of straight driving (start point of driving just before turning) P2 Turning start point (end point just before turning) P3 End of turning (loading point) S Loading Control System T-track Tn loading platform Ts Luggage compartment wall

Claims

1. In a loading control system that controls the loading of cargo onto a truck bed by a forklift, a loading point determination unit that determines a loading point at which the cargo is to be loaded onto the loading platform; a turning route determination unit that determines a circular arc turning route by determining a turning start point that is connected to the loading point as a turning end point by an arc having a certain curvature; The forklift turns from the turning start point to the turning end point according to the turning route determined by the turning route determination unit, and loads the cargo at the loading point determined by the loading point determination unit. A loading control system characterized by:

2. an external device capable of communicating with the forklift; The external device includes the loading point determination unit and the turning route determination unit.

2. The load control system of claim 1.

3. a pre-turning route determination unit that determines a pre-turning route along which the steering angle of the forklift truck is set to an angle for turning at the constant curvature when the forklift truck reaches the turning start point, The forklift travels to the turning travel start point according to the immediately before turning route determined by the immediately before turning route determination unit.

2. The load control system of claim 1.

4. an external device capable of communicating with the forklift; The external device includes the loading point determination unit, the turning route determination unit, and the immediately before turning route determination unit.

4. The loading control system of claim 3.

5. the forklift includes a sensor that detects an object located above the loading platform; The loading point determination unit determines the loading point based on a result of object detection by the sensor. A loading control system according to any one of claims 1 to 4.

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