Conveyance device and control device

Abstract

To provide a conveyance device capable of specifying and automatically entering a pallet to be entered.SOLUTION: A conveyance device for conveying a pallet comprises: a carriage part which enters an internal space of the pallet and loads and conveys the pallet; and a control unit which controls the conveyance device. The carriage part includes a measurement unit which scans with laser light to obtain first point cloud data which is a point cloud of three-dimensional information on an object in a scanning space and second point cloud data which is a point cloud of two-dimensional information on the object. The control unit includes: a calculation processing unit which detects a pallet from the first point cloud data and calculates a position of the pallet and a position and orientation of the carriage part relative to the pallet based on the second point cloud data; and an operation control unit which causes the carriage part to directly face a pallet to be entered and enter the internal space of the pallet based on a calculation processing result by the calculation processing unit.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a conveying device and a control device for conveying a pallet.

Background Art

[0002] In recent years, the automation of vehicles for transporting goods has been progressing. Also in steelworks, the automation of conveying devices for transporting steel products such as slabs and work-in-progress is being promoted.

[0003] For example, as a conveying device for conveying a slab, there is a slab carrier. The slab carrier enters below a pallet, which is a pedestal on which the slab is placed, raises the pallet, and conveys the slab together with the pallet. When the slab carrier enters the pallet, the distance between both ends of the slab carrier and the pallet is only about 15 cm, and extremely delicate operation is required. Therefore, the operator relies on sensibility and experience while looking at the mark of the pallet, and performs turning operation and diagonal operation of the slab carrier to steer the position and inclination of the slab carrier so as not to contact the pallet. If such an operation of the slab carrier entering the pallet can be automated, the conveying work can be labor-saving.

[0004] For example, Patent Document 1 discloses an automated guided vehicle that loads and conveys a pallet, and includes an approach sensor that measures the distance and direction from surrounding objects, a side sensor that measures the distance and direction from surrounding objects, a leg detection means that detects the legs of the pallet from the measurement data measured by the approach sensor or the side sensor, and a steering angle calculation means that calculates the steering angle of the automated guided vehicle based on the legs of the pallet detected by the leg detection means.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Since the pallet is a pedestal that is transported together with the slab by a slab carrier, the position of the pallet in the steelworks is indefinite. There are some pallets placed alone, and there are also cases where a plurality of pallets are placed in parallel. However, the automated guided vehicle described in Patent Document 1 above can automatically enter one pallet determined as the entry target, but it cannot discriminate the pallet to be entered in a situation where a plurality of pallets are placed.

[0007] Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a transport device and a control device capable of specifying a pallet to be entered and automatically entering it.

Means for Solving the Problems

[0008] In order to solve the above problems, according to an aspect of the present invention, there is provided a transport device for transporting a pallet having a placement portion on which a transported object is placed and a pair of column portions that support the placement portion, the transport device including: a carriage portion that enters a pallet internal space surrounded by the placement portion and the pair of column portions, loads and transports the pallet; and a control portion that controls the transport device, the carriage portion having a measurement portion that scans laser light and acquires first point cloud data that is a point cloud of three-dimensional information of an object in a scanning space and second point cloud data that is a point cloud of two-dimensional information of the object, the control portion detecting the pallet by detecting the placement portion and the pair of column portions from the first point cloud data, and calculating the position of the pallet, the position and orientation of the carriage portion with respect to the pallet based on the second point cloud data, and a driving control portion that causes the carriage portion to face the pallet to be entered and enter the pallet internal space based on the calculation processing result by the calculation processing portion.

[0009] The arithmetic processing unit may scan the second point cloud data corresponding to the pallet in a plan view with a scanning frame of a preset size, extract a point cloud area where the number of points within the scanning frame is equal to or greater than a threshold value, cluster the extracted point cloud areas, and obtain a pillar line indicating the position of the pillar portion arranged in the depth direction of the pallet from the candidate point clouds included in the areas belonging to the same class. Then, the operation control unit may cause the carriage unit to enter the internal space of the pallet based on the pillar lines corresponding to the pair of pillar portions obtained by the arithmetic processing unit, and the position and orientation of the carriage unit.

[0010] In each of the point cloud areas extracted by clustering, when the absolute value of the slope of the straight line passing through two separated points is greater than a predetermined threshold value, the arithmetic processing unit may exclude the two points from the point cloud of the point cloud area, and obtain a pillar line from the points included in the point cloud area belonging to the same class from which the two points have been excluded.

[0011] When the arithmetic processing unit detects one pallet from the first point cloud data, the operation control unit designates the detected pallet as the pallet to be entered by the transport device. When the arithmetic processing unit detects a plurality of pallets from the first point cloud data, the operation control unit may designate the pallet with the center of the carriage unit located between the pair of pillar portions as the pallet to be entered by the transport device.

[0012] When the arithmetic processing unit detects a plurality of pallets from the first point cloud data and the center of the carriage unit is not located between the pair of pillar portions, the operation control unit calculates the intermediate position between the pair of pillar portions for each of the detected pallets, and may designate the pallet with the minimum distance between the carriage unit and the intermediate position as the pallet to be entered by the transport device.

[0013] The carriage unit of the transport device may include an inertial measurement unit that measures the movement amount of the carriage unit. At this time, after the carriage unit enters the internal space of the pallet, the operation control unit may stop the carriage unit at the stop position based on the movement amount of the carriage unit measured by the inertial measurement unit or the speed signal of the transport device.

[0014] Also, in order to solve the above problems, according to another aspect of the present invention, there is provided a control device for controlling a transport device that transports a pallet. The transport device includes a cart unit that enters a pallet internal space surrounded by a pallet placement portion and a pair of column portions, loads and transports the pallet, and a measurement unit that is provided on the cart unit, scans laser light, and acquires first point cloud data that is a point cloud of three-dimensional information of an object in a scanning space and second point cloud data that is a point cloud of two-dimensional information of the object. The control device detects the pallet by detecting the placement portion and the pair of column portions from the first point cloud data acquired by the measurement unit, and calculates the position and orientation of the cart unit with respect to the pallet from the second point cloud data acquired by the measurement unit. The control device includes an arithmetic processing unit and an operation control unit that causes the cart unit to enter the pallet internal space facing the pallet to be entered based on the arithmetic processing result by the arithmetic processing unit.

Advantages of the Invention

[0015] As described above, according to the present invention, the transport device can identify the pallet to be entered and automatically enter it.

Brief Description of the Drawings

[0016]

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Best Mode for Carrying Out the Invention

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[0018] [1. Configuration of Slab Carrier (Transport Device)] First, based on FIGS. 1 to 3, the configuration of the slab carrier 10 according to an embodiment of the present invention will be described. FIG. 1 is an explanatory diagram showing the operation when the pallet 20 of the slab carrier 10 is being transported. FIG. 2 is an explanatory diagram for explaining the travel control when entering the pallet 20 of the slab carrier 10 according to the present embodiment. FIG. 3 is a block diagram showing the functional configuration of the control unit 50 of the slab carrier 10. Although not shown in FIGS. 1 and 2, a slab, which is the object to be transported, may be placed on the pallet 20.

[0019] The slab carrier 10 is a transport device that transports the pallet 20 (and further, the slab placed on the upper part of the pallet 20). The pallet 20 is, for example, as shown in FIG. 2, a gantry having a placement portion 21 on which an object to be transported such as a slab is placed, and a pair of column portions 23 that support the placement portion 21. When the width direction of the pallet 20 is the X direction, the longitudinal direction (depth direction) is the Y direction, and the height direction is the Z direction, the placement portion 21 is installed substantially parallel to the XY plane at a predetermined height position, and the column portions 23 are provided in pairs on both sides in the width direction of the placement portion 21. The slab carrier 10 enters the space below the pallet (the internal space V of the pallet) surrounded by the placement portion 21 of the pallet 20 and the corresponding column portions 23.

[0020] Note that the column portion 23 includes a vertical member 23a that extends vertically from the placement portion 21 toward the road surface, and an inclined member 23b that extends obliquely from the placement portion 21 toward the road surface. A plurality of pairs of the vertical member 23a and the inclined member 23b are provided in the longitudinal direction. A row of the column portions 23 arranged along the longitudinal direction is also referred to as a column line. Also, an axis along the longitudinal direction (Y direction) passing through the center position in the width direction (X direction) when the pallet 20 is viewed in plan is defined as the pallet center axis C2.

[0021] The slab carrier 10, which is a conveying device for conveying such a pallet 20, as shown in Fig. 1, when conveying the pallet 20, first advances toward the pallet 20 which is a pedestal on which the slab is placed, enters below the pallet 20 and stops. Then, the slab carrier 10 lifts the pallet 20 and retreats together with the pallet 20 to carry out the pallet 20 (and further the slab placed on the upper part of the pallet 20). The slab carrier 10 according to the present embodiment conveys the pallet 20 by automatic operation.

[0022] In the automatic operation of the slab carrier 10 according to the present embodiment, LiDAR (Light Detection And Ranging), which is a kind of optical measurement method capable of acquiring distance information at high density, is used. LiDAR is a technology that irradiates laser light from a vehicle, measures the time until it hits an object and returns, and measures the distance and direction to the object. In the present embodiment, two types of LiDAR are installed on the slab carrier 10, and using the detection results of each, the detection of the target pallet 20 to enter and the automatic entry of the slab carrier 10 into the target pallet 20 are realized.

[0023] More specifically, as shown in Fig. 2, the slab carrier 10 includes a carriage part 11, a measurement part 30, and a control part 50.

[0024] (Carriage part) The carriage unit 11 enters the interior space V of the pallet at the lower part of the pallet 20, loads and conveys the pallet 20. The carriage unit 11 has a flat outer shape as shown in FIG. 2, for example, so as to easily enter the interior space of the pallet. The carriage unit 11 has wheels 13 driven by a drive unit (not shown). By controlling the direction of the wheels 13 and the direction of rotation of the wheels 13 in a plan view, the carriage unit 11 can not only go straight in the front-rear direction (Y direction), but also turn and travel obliquely on the road surface (XY plane). In addition, the carriage unit 11 is provided with a lifting mechanism (not shown) for raising and lowering the pallet 20 in the height direction (Z direction). Note that an axis along the front-rear direction (Y direction) passing through the center position in the width direction (X direction) of the carriage unit 11 is defined as the carrier center axis C1 of the slab carrier 10.

[0025] (Measurement unit) A measurement unit 30 is installed in the carriage unit 11 of the slab carrier 10. The measurement unit 30 scans laser light to acquire first point cloud data which is a point cloud of three-dimensional information of an object in the scanning space, and second point cloud data which is a point cloud of two-dimensional information of the object.

[0026] For example, as shown in FIG. 2, the carriage unit 11 is provided with two LiDARs, a first measurement unit 31 and a second measurement unit 32, as the measurement unit 30 on the front side (positive Y-axis side) facing the pallet 20 to be entered. The first measurement unit 31 is a 3D-LiDAR, which scans laser light in the horizontal direction (X direction) and the vertical direction (Z direction) to acquire first point cloud data which is a point cloud of three-dimensional information of an object in the scanning space. The second measurement unit 32 is a 2D-LiDAR, which scans laser light in the horizontal direction (X direction) to acquire second point cloud data which is a point cloud of two-dimensional information of an object in the scanning plane.

[0027] 3D-LiDAR can obtain three-dimensional information in a three-dimensional manner and can detect the position, shape, size, etc. of objects in the scanning space at a high density. On the other hand, in order to realize the automatic driving of the slab carrier 10, it is necessary to control the slab carrier 10 with a control cycle of about 100 msec. However, since the responsiveness of 3D-LiDAR is not very high, it is difficult to control the automatic driving of the slab carrier 10 based only on the detection results of 3D-LiDAR.

[0028] 2D-LiDAR acquires two-dimensional information in a planar manner. Since the scanning direction of 2D-LiDAR is in one direction, it has higher responsiveness than 3D-LiDAR and can acquire two-dimensional information faster than the control cycle of the automatic driving of the slab carrier 10. In addition, 2D-LiDAR has a larger scanning angle (for example, about 180°) than 3D-LiDAR and can scan a wide range. On the other hand, when a plurality of pallets 20 are arranged in parallel, it is difficult to identify the boundary of the adjacent pallets 20 and detect the pallet 20 to be entered only based on the detection results of 2D-LiDAR.

[0029] The slab carrier 10 according to the present embodiment detects the pallet 20 to be entered using the first point cloud data when the slab carrier 10 is located outside the pallet 20, and when the slab carrier 10 is located inside the pallet 20, it uses the second point cloud data to detect the column portion 23 of the pallet 20 to be entered, recognizes the position and orientation of the slab carrier 10, and performs automatic entry.

[0030] (Control Unit) The control unit 50 is mounted on the cart unit 11 and controls the operation of the slab carrier 10. The control unit 50 can be configured by an information processing device such as a computer including a CPU, a ROM, a RAM, etc. As shown in FIG. 3, the control unit 50 has an arithmetic processing unit 51 and an operation control unit 53.

[0031] The arithmetic processing unit 51 processes the first point cloud data and the second point cloud data acquired by the measurement unit 30. The first point cloud data is a point cloud of three-dimensional information of an object in the scanning space, and can be acquired, for example, by the first measurement unit 31 (3D-LiDAR). The second point cloud data is a point cloud of two-dimensional information of an object between the scanning surfaces, and can be acquired, for example, by the second measurement unit 32 (2D-LiDAR). In order to make the slab carrier 10 enter the pallet 20, it is necessary to calculate from the point cloud data the position of the pallet 20 and the position and orientation of the carriage part 11 of the slab carrier 10 with respect to the pallet 20, align the slab carrier 10 with the pallet 20, and then move the slab carrier 10 forward. The arithmetic processing unit 51 processes the first point cloud data and the second point cloud data and acquires the information necessary for automatically driving the slab carrier 10.

[0032] Specifically, the arithmetic processing unit 51 detects the pallet to be entered by detecting the frame of the pallet 20 (that is, the placement part 21 and the pair of column parts 23. Hereinafter, also referred to as the "pallet frame") from the first point cloud data. The pallet frame has a gate shape when viewed from the front. The space inside the pallet frame becomes the space (the inner space V of the pallet) into which the slab carrier 10 enters. The first point cloud data consists of a plurality of detection points where the measurement unit 30 detects an object in the scanning space. The arithmetic processing unit 51 detects the pallet frame by specifying a location where the detection points are distributed in a gate shape in the first point cloud data. The arithmetic processing unit 51 can also detect the gate-shaped frames of the respective pallets 20 from the first point cloud data even when a plurality of pallets 20 are arranged side by side.

[0033] Further, the arithmetic processing unit 51 calculates the position information of the pallet 20 and the position and orientation of the carriage unit 11 with respect to the pallet 20 based on the second point cloud data. The second point cloud data consists of a plurality of detection points detected by the measurement unit 30 within the scanning plane for an object. Since the slab carrier 10 enters the internal space V of the pallet, for example, the second measurement unit 32 of the measurement unit 30 that acquires the second point cloud data is installed on the carriage unit 11 at a height position that does not contact the placement unit 21 of the pallet 20. Therefore, in the second point cloud data acquired by the second measurement unit 32, the detection points are distributed at the positions of the column portions 23 of the pallet 20 when the pallet 20 is viewed in plan (i.e., when viewed in the Z direction). Accordingly, the arithmetic processing unit 51 can calculate the position of the column portion 23 of the pallet 20 from the second point cloud data, and can also calculate the position and orientation of the carriage unit 11 with respect to the pallet 20.

[0034] Details of the arithmetic processing by the arithmetic processing unit 51 will be described later. The arithmetic processing unit 51 detects the position of the pallet 20 every time the first point cloud data is input from the measurement unit 30, and calculates the position of the pallet 20, the position and orientation of the carriage unit 11 every time the second point cloud data is input. The arithmetic processing unit 51 outputs the arithmetic processing result to the operation control unit 53.

[0035] Based on the arithmetic processing result of the arithmetic processing unit 51, the operation control unit 53 causes the carriage unit 11 to enter the internal space of the pallet while facing the target pallet 20 head-on. The operation control unit 53 can recognize the position of the pallet 20 in the forward direction of the carriage unit 11 from the arithmetic processing result of the arithmetic processing unit 51, and can recognize what posture the carriage unit 11 is in with respect to the pallet 20 (i.e., the position and orientation with respect to the pallet 20). The operation control unit 53 controls the slab carrier 10 so that the carrier central axis C1 of the slab carrier 10 coincides with the central axis C2 of the pallet 20 based on the arithmetic processing result of the arithmetic processing unit 51.

[0036] During the automatic driving of the slab carrier 10, the driving control unit 53, based on the calculation result of the arithmetic processing unit 51, corrects the posture of the slab carrier 10 so as to face the pallet 20 that is the entry target, and then moves the slab carrier 10 forward toward the internal space V of the pallet. When the slab carrier 10 reaches the position to lift the pallet 20, the driving control unit 53 stops the slab carrier 10. Then, after lifting the pallet 20, the driving control unit 53 moves the slab carrier 10 backward together with the pallet 20.

[0037] (Inertial Measurement Unit) As shown in FIG. 2, the slab carrier 10 may be provided with an inertial measurement unit 60 that measures the movement amount of the carriage unit 11. The inertial measurement unit 60 may be, for example, an IMU (Internal Measurement Unit). The IMU includes an acceleration sensor and a gyro sensor and can measure three-dimensional inertial motion (translational motion and rotational motion in three axial directions). By providing the inertial measurement unit 60 on the slab carrier 10, for example, the movement amount of the slab carrier 10 can be obtained from the measurement result of the inertial measurement unit 60.

[0038] The configuration of the slab carrier 10 according to the present embodiment has been described above.

[0039] [2. Driving Control of Slab Carrier] The slab carrier 10 according to the present embodiment uses, by the control unit 50, the first point cloud data that is the point cloud of the three-dimensional information of the object measured by the measurement unit 30 and the second point cloud data that is the point cloud of the two-dimensional information of the object to identify the pallet 20 that is the entry target and automatically enter the slab carrier 10. Here, FIG. 4 shows an example of the positional relationship between the slab carrier 10 and the pallet 20 when viewed in plan. As information necessary to realize the automatic entry of the slab carrier 10 into the pallet 20, there are the following three pieces of information shown in FIG. 4.

[0040] (1) The distance from the pallet center Q2 to the carrier center Q1 when viewed in plan (center-to-center distance D) (2) The relative displacement amount (steering direction displacement amount d) of the carrier center axis C1 with respect to the straight line L extending from the pallet center Q2 toward the slab carrier 10 when viewed in plan on the front surface of the slab carrier C (3) The angle (yaw angle θ) formed by the carrier center axis C with respect to the straight line L extending from the pallet center Q2 toward the slab carrier 10 when viewed in plan C

[0041] These pieces of information can be calculated from the first point group data and the second point group data. For the automatic approach of the slab carrier 10, the arithmetic processing unit 51 needs to process the first point group data and the second point group data at a target control cycle (for example, about 100 msec) for controlling the automatic operation of the slab carrier 10 to obtain these pieces of information.

[0042] Further, when a plurality of pallets 20 are placed, it is necessary to correctly detect the pallet frame so as not to recognize that the column portions 23 of adjacent different pallets 20 are a pair of column portions 23 constituting the pallet frame.

[0043] Therefore, in the slab carrier 10 according to the present embodiment, the control unit 50 processes the first point group data and the second point group data to calculate the above three pieces of information (center - to - center distance D, steering direction displacement amount d, yaw angle θ) and detect the pallet frame, and controls the operation of the slab carrier 10. Hereinafter, the arithmetic processing of the control unit 50 will be described in detail.

[0044] [2 - 1. Pallet identification process] ​​First, based on FIGS. 5 to 8, a process of identifying a pallet 20 to be entered by the slab carrier 10 will be described. FIG. 5 is a flowchart showing an example of the pallet identification process according to the present embodiment. FIG. 6 is an image showing an example of point cloud data acquired by the first measurement unit 31 (3D-LiDAR) and the second measurement unit 32 (2D-LiDAR). FIG. 7 is an explanatory diagram showing an example of the positional relationship between the slab carrier 10 and a plurality of pallets 20 when a plurality of pallets 20 that can be entered are placed. FIG. 8 is an explanatory diagram for explaining a process of determining the pallet 20 to be entered when the carrier central axis C1 of the slab carrier 10 is outside the pallet frame.

[0045] (S100: Detection of Pallet) First, the arithmetic processing unit 51 of the control unit 50 detects the pallet frame of the pallet 20 and a pair of pillar portions 23 in the scanning space from the first point cloud data acquired by the measurement unit 30 (S100).

[0046] The first point cloud data is a point cloud of detection points that detect an object in the scanning space, and can be acquired, for example, by the first measurement unit 31 which is a 3D-LiDAR. One detection point has three-dimensional information consisting of position information in the horizontal direction (X direction), depth direction (Y direction), and vertical direction (Z direction). That is, the three-dimensional shape of an object in the scanning space can be grasped from the first point cloud data.

[0047] For example, when the space where the pallet 20 is located is measured by the first measurement unit 31 (3D-LiDAR) and the second measurement unit 32 (2D-LiDAR), a measurement result as shown in FIG. 5 is obtained. FIG. 5 shows the first point cloud data PG1 acquired by the first measurement unit 31 (3D-LiDAR) and the second point cloud data PG2 acquired by the second measurement unit 32 (2D-LiDAR). From the first point cloud data PG1, a portal-shaped pallet frame formed by the placement portion 21 of the pallet 20 and a pair of pillar portions 23 can be specified. Note that from the second point cloud data PG2, the position of the pillar portion 23 at the height position where the pallet 20 is located can be specified.

[0048] The arithmetic processing unit 51 detects the pallet frame of the pallet 20 included in the scanning space from the first point cloud data PG1. Further, the arithmetic processing unit 51 identifies the two column portions 23 connected to both ends of one placement portion 21 as a pair of column portions 23 that constitute the pallet frame together with the placement portion 21. When a plurality of pallet frames are detected from the first point cloud data PG1, the arithmetic processing unit 51 identifies a pair of column portions 23 for each pallet frame.

[0049] (S110 - S150: Identification of the pallet to enter) Next, the operation control unit 53 identifies the pallet 20 to be entered by the slab carrier 10 from the pallet 20 detected by the arithmetic processing unit 51. At this time, the operation control unit 53 sets the pallet 20 closest to the slab carrier 10 as the pallet 20 to be entered.

[0050] Specifically, first, the operation control unit 53 determines whether the number of pallet frames (that is, the number of pallets 20) detected by the arithmetic processing unit 51 in step S100 is plural (S110). If one detected pallet frame is present (S110: NO), the operation control unit 53 sets the pallet 20 of the one detected pallet frame as the pallet 20 to be entered (S120). On the other hand, if a plurality of detected pallet frames are present (S110: YES), the operation control unit 53 determines whether the carrier central axis C1 of the slab carrier 10 is within the pallet frame from the second point cloud data PG2 acquired by the measurement unit 30 (S130). The second point cloud data PG2 is a point cloud of detection points that detect an object in the scanning plane, and can be acquired by a second measurement unit 32 such as 2D - LiDAR.

[0051] For example, as shown in FIG. 7, when three pallets 20 (20A, 20B, 20C) are arranged in parallel, in step S100, the arithmetic processing unit 51 detects the pallet frames of the three pallets 20 and a pair of column portions 23 from the first point group data PG1. However, the responsiveness of the first measurement unit 31 (3D-LiDAR) is not very high. On the other hand, the second measurement unit 32 (2D-LiDAR) has higher responsiveness than the first measurement unit 31 (3D-LiDAR) and can acquire two-dimensional information at a speed faster than the control cycle of the automatic driving of the slab carrier 10.

[0052] Therefore, the operation control unit 53 uses the positions of the pair of column portions 23 calculated by the arithmetic processing unit 51 from the second point group data PG2 to determine whether the carrier center axis C1 of the slab carrier 10 is within the pallet frame. Details of the arithmetic processing of the second point group data PG2 performed by the arithmetic processing unit 51 will be described later. Here, it is assumed that three pieces of information (center-to-center distance D, steering direction position deviation amount d, yaw angle θ) are calculated and acquired from the second point group data PG2 by the arithmetic processing unit 51 at the control cycle of the operation control unit 53.

[0053] The operation control unit 53 determines whether the carrier center axis C1 of the slab carrier 10 is within the pallet frame, for example, by determining whether the position of the carrier center axis C1 of the slab carrier 10 in the horizontal direction (X direction) is located between the pair of column portions 23 of the pallet 20. The operation control unit 53 calculates the distance between the pair of column portions 23 detected in step S100 from the positions of the column portions 23 calculated by the arithmetic processing unit 51 from the second point group data PG2.

[0054] When the carrier center axis C1 is within the pallet frame (S130: YES), the operation control unit 53 sets the pallet 20 in which the carrier center axis C1 is within the pallet frame as the pallet 20 to be entered (S140). For example, in the example shown in FIG. 7, the carrier center axis C1 of the slab carrier 10 is within the pallet frame of the pallet 20B. Therefore, the operation control unit 53 sets the pallet 20B as the pallet 20 to be entered.

[0055] On the other hand, when the carrier central axis C1 is not within the pallet frame (S130: NO), the operation control unit 53 sets the pallet 20 closest to the slab carrier 10 as the target pallet for entry (S150). Although multiple pallet frames are detected, the case where the carrier central axis C1 is not within the pallet frame may be considered as the case where the carrier central axis C1 is at the boundary position of the adjacent pallets 20. For example, in the example shown in FIG. 8, the carrier central axis C1 of the slab carrier 10 is between the column portion 23AR of the pallet 20A and the column portion 23BL of the pallet 20B.

[0056] At this time, based on the information obtained by the arithmetic processing unit 51 processing the second point group data PG2, the operation control unit 53 calculates which of the two pallets 20A and 20B is closer to the slab carrier 10, and determines the target pallet for entry. For example, for each detected pallet 20, the operation control unit 53 calculates the intermediate position of the pair of column portions 23, and sets the pallet 20 with the minimum distance between the carriage portion 11 and the intermediate position of the pair of column portions 23 as the target pallet for entry.

[0057] Explaining with the example shown in FIG. 8, by the time of the processing in step S150, it is known that the carrier central axis C1 is located between the column portion 23AR of the pallet 20A and the column portion 23BL of the pallet 20B. Therefore, the operation control unit 53 first identifies the positions of the pair of column portions 23 (that is, the column portions 23AL, 23AR of the pallet 20A and the column portions 23BR, 23BL of the pallet 20B) from the second point group data PG2 for the pallets 20A and 20B. Next, the operation control unit 53 calculates the intermediate position Ja of the pair of column portions 23AL, 23AR of the pallet 20A and the intermediate position Jb of the pair of column portions 23BL, 23BR of the pallet 20B.

[0058] Then, the operation control unit 53 calculates the distance from the intermediate position between the pair of column portions 23 to the carrier central axis C1 in the direction orthogonal to the carrier central axis C1 of the slab carrier 10. That is, the operation control unit 53 calculates, for the pallet 20A, the distance Ka from the intermediate position Ja between the pair of column portions 23AL and 23AR to the carrier central axis C1, and for the pallet 20B, the distance Kb from the intermediate position Jb between the pair of column portions 23BL and 23BR to the carrier central axis C1.

[0059] Thereafter, the operation control unit 53 compares the distance Ka and the distance Kb, and sets the pallet 20 with the smaller distance as the pallet 20 to be entered. For example, in the example shown in FIG. 8, the distance Ka is smaller than the distance Kb. Therefore, the operation control unit 53 sets the pallet 20A as the pallet 20 to be entered. When the distance Ka and the distance Kb are the same, the operation control unit 53 may randomly select one from the pallet 20A and the pallet 20B, or select one based on a preset condition, as the pallet 20 to be entered.

[0060] The process of specifying the pallet 20 to be entered for the slab carrier 10 to enter has been described above.

[0061] [2-2. Information acquisition process from the second point cloud data] Based on FIGS. 9 to 13, a process of acquiring information (center-to-center distance D, steering direction positional deviation amount d, yaw angle θ) necessary for controlling the automatic driving of the slab carrier 10 from the second point cloud data PG2 will be described. FIG. 9 is a flowchart showing an example of the information acquisition process from the second point cloud data PG2 by the arithmetic processing unit 51. FIG. 10 is an explanatory diagram for explaining the process of detecting the point cloud at the positions of the pair of column portions 23 from the second point cloud data PG2. FIG. 11 is an explanatory diagram for explaining the process of removing the detection points that cause disturbances from the point cloud at the position of one column portion 23. FIG. 12 is an explanatory diagram for explaining the integration of the carrier coordinate system and the pallet coordinate system. FIG. 13 is an explanatory diagram for explaining the calibration of the carrier coordinate system.

[0062] (A. Calculation of the column line of the pallet) First, based on FIGS. 9 to 11, a process of calculating a straight line (pillar line) indicating the positions of the pillar portions 23 arranged in the depth direction of the pallet 20 will be described.

[0063] As described above, the second point cloud data PG2 processed by the arithmetic processing unit 51 is a point cloud of detection points that detect an object in the scanning plane, and can be acquired by the second measurement unit 32 which is, for example, a 2D-LiDAR. Since the second measurement unit 32 according to the present embodiment scans the laser beam in the horizontal direction (X direction), one detection point has the positions in the horizontal direction (X direction) and the depth direction (Y direction) at a height position in a certain vertical direction (Z direction) as two-dimensional information. That is, the position of the object in the scanning plane (XY plane) can be grasped from the second point cloud data PG2. For example, as shown in FIG. 5, when a certain space of the pallet 20 is measured, the positions of the pillar portions 23 constituting the pallet 20 can be specified from the second point cloud data PG2 acquired by the second measurement unit 32 (2D-LiDAR).

[0064] (S200, S210: Determination of the point cloud processing range in the second point cloud data) First, when the arithmetic processing unit 51 acquires the second point cloud data PG2 from the second measurement unit 32 (S200), it selects a range for detecting the pillar portion 23 in the second point cloud data PG2 (hereinafter also referred to as "point cloud processing range A") (S210).

[0065] The second measurement unit 32 which is a 2D-LiDAR can scan the inside of the scanning plane over a wide range. For this reason, the second point cloud data PG2 includes detection points of objects detected in a wide range in front of the slab carrier 10. However, when, for example, it is only necessary to detect the pillar portion 23 of the pallet 20 facing the slab carrier 10, it is not necessary to process all the second point cloud data PG2 acquired by the second measurement unit 32. By limiting the range for detecting the positions of the pillar portions 23 of the pallet 20 from the second point cloud data PG2 in step S210, the processing of the arithmetic processing unit 51 can be performed efficiently. The point cloud processing range A may be, for example, a range including the pallet frame specified from the first point cloud data PG1.

[0066] (S220: Extraction of candidate point group) Next, the arithmetic processing unit 51 selects a candidate for a point group (hereinafter also referred to as a "candidate point group") for obtaining a straight line (column line) indicating the position of the column portion 23 along the depth direction (Y direction) from the point group processing range A selected in step S210 (S220). The obtained second point group data PG2 includes disturbances such as sand scattered in the scanning plane and surrounding vegetation in addition to the column portions 23 of the pallet 20. Therefore, the arithmetic processing unit 51 scans the point group processing range A of the second point group data PG2, which is two-dimensional point group data, with a preset scanning frame F, and extracts a point group in which detection points are concentrated. As a result, detection points that can be a point group for obtaining a column line can be extracted, and detection points that have detected disturbances such as scattered sand and surrounding vegetation can be excluded from the candidate point group.

[0067] For example, as shown in FIG. 10, when the pallet 20 is in the point group processing range A, a plurality of detection points appear collectively at positions corresponding to the column portions 23 of the pallet 20 within the point group processing range A. Therefore, the arithmetic processing unit 51 scans the point group processing range A with the scanning frame F, and extracts a point group area in which the number of detection points within the scanning frame F is equal to or greater than a threshold value as a portion where the column portion 23 exists. In the example of FIG. 10, six point group areas G1 to G6 are extracted from the point group processing range A. As a result, detection points that deviate from the concentrated point group such as the detection point P0 are excluded from the candidate point group.

[0068] The threshold value for extracting the point group area may be, for example, the number of detection points that can identify the detection target based on the number of detection points included in the portion corresponding to the detection target in the obtained point group data by previously measuring the detection target with the second measurement unit 32 (2D-LiDAR) to obtain point group data. Further, the shape and size of the scanning frame F may be set according to the shape and size of the object to be detected. For example, in the present embodiment, the shape and size of the scanning frame F may be the shape and size of the column portion 23 on the scanning surface.

[0069] The arithmetic processing unit 51 clusters the extracted point group areas G1 to G6 and classifies the point group areas on the same line segment along the depth direction (Y direction). The clustering may be performed by a well-known clustering method. In the example of FIG. 10, the point group areas G1 to G6 are classified into two classes: the point group areas G1 to G3 and the point group areas G4 to G6. The straight line (column line L L ) based on the point group areas G1 to G3 obtained by the processing described later and the straight line (column line L R ) based on the point group areas G4 to G6 will indicate the positions of the pair of column parts 23 of the pallet 20.

[0070] (S230, S240: Removal of disturbances in the candidate point group) Then, the arithmetic processing unit 51 removes the detected points that are disturbances from the candidate point group extracted in step S220. By the processing of step S220, the detected points that detect disturbances such as scattered sand and surrounding vegetation are excluded, but the detected points that are also disturbances may be included in the point group area. Therefore, by excluding the detected points that are disturbances from the point group area, the accuracy of the line segment (column line) in which the column parts 23 of the finally specified pallet 20 are arranged in the depth direction can be improved.

[0071] Specifically, the arithmetic processing unit 51 first calculates a plurality of straight lines passing through two points included in the point group for each point group area for the candidate point group extracted in step S220 (S230). The two detected points through which the straight line passes are separated within the point group, and the distance between the two points is assumed to be large. For example, the arithmetic processing unit 51 extracts pairs of the top N detected points from the pairs of detected points with the largest separation distance. Then, for each of the plurality (N) of pairs of the extracted detected points, a straight line passing through the paired detected points is calculated.

[0072] For example, Fig. 11 shows an example of a point group included in a certain point group area. When the number of pairs of detection points to be extracted is four (N = 4), assume that pairs of detection points, pair 1 (P1, P2), pair 2 (P3, P4), pair 3 (P3, P6), and pair 4 (P5, P6) are extracted. From this, straight lines L1 passing through pair 1 (P1, P2), L2 passing through pair 2 (P3, P4), L3 passing through pair 3 (P3, P6), and L4 passing through pair 4 (P5, P6) can be calculated.

[0073] Then, among the calculated straight lines, since it is considered that there are detection points at positions deviated from the aggregated point group for those with an absolute value of the slope greater than a predetermined threshold, the arithmetic processing unit 51 excludes the pairs of detection points constituting the straight line from the point group (S240). The threshold for the absolute value of the slope may be, for example, about 0.08 to 0.10, and the slope may be allowed up to about ±5° with respect to the Y direction. In the example of Fig. 11, the slope of straight line L1 exceeds the threshold. Therefore, the arithmetic processing unit 51 excludes the detection points P1 and P2 constituting the straight line L1 from the candidate point group.

[0074] The arithmetic processing unit 51 performs the processes of steps S230 and S240 for all point group areas to exclude the detection points that cause disturbances.

[0075] (S250: Estimation of the column line of the pallet) Thereafter, the arithmetic processing unit 51 estimates one straight line from the detection points after removing the detection points that cause disturbances in step S240 for each class of the point group areas clustered in step S220 (S250). The arithmetic processing unit 51 sets the estimated straight line as the straight line along which the column portions 23 of the pallet 20 are arranged in the depth direction (i.e., the column line). The arithmetic processing unit 51 may use, for example, an approximate straight line obtained by the least squares method as the column line of the pallet 20.

[0076] For example, as shown in Fig. 10, the arithmetic processing unit 51 calculates the column line L by the least squares method from the detection points included in the point group areas G1 to G3 after removing disturbances in step S240. LAfter obtaining it and removing disturbances in step S240, the column line L is obtained from the detection points included in the point group areas G4 to G6 by the least squares method. R Thereby, the arithmetic processing unit 51 can obtain a straight line (column line) in which a pair of column portions 23 of the pallet 20 are arranged in the depth direction.

[0077] As described above, the column line L of the pallet 20 L , L R has been described in terms of the calculation process.

[0078] The arithmetic processing unit 51 calculates the center-to-center distance D, the steering direction position deviation amount d, and the yaw angle θ necessary for controlling the automatic driving of the slab carrier 10 from the two-dimensional information of the detection points obtained from the second point group data PG2 and the calculated column lines L of the pallet 20. L , L R

[0079] The center-to-center distance D from the pallet center Q2 to the carrier center Q1 can be calculated from the dimensions of the slab carrier 10, the dimensions of the pallet 20, and the two-dimensional information of the column portion 23 of the pallet 20 obtained from the second point group data PG2.

[0080] The steering direction position deviation amount d, which is the relative position deviation amount between the carrier center axis C1 and the pallet center axis C2 on the front surface of the slab carrier, can be calculated from the dimensions of the slab carrier 10, the dimensions of the pallet 20, the two-dimensional information of the column portion 23 of the pallet 20 obtained from the second point group data PG2, and the column lines L of the pallet 20. L , L R The arithmetic processing unit 51 can obtain a straight line (the straight line L shown in FIG. 4) passing through the intermediate position of the pair of column portions 23 parallel to the column lines L. L , L R C ) of the pallet 20. Such a straight line L C can be regarded as the pallet center axis C2 of the pallet 20.

[0081] The yaw angle θ of the slab carrier 10 is based on the dimensions of the slab carrier 10, the dimensions of the pallet 20, the two-dimensional information of the column portion 23 of the pallet 20 obtained from the second point group data PG2, and the column line L L , L R of the pallet 20, and can be calculated from. As described above, the column line L L , L R of the pallet 20 is used to obtain the pallet central axis C2. The arithmetic processing unit 51 obtains the angle formed by the carrier central axis C1 and the pallet central axis C2 as the yaw angle θ.

[0082] Based on the center - to - center distance D, the steering - direction positional deviation amount d, and the dimensions of the slab carrier 10 obtained by the above - described method, the arithmetic processing unit 51 calculates the center coordinates of the slab carrier 10 and calculates a control amount so as to match the pallet coordinate center. The arithmetic processing unit 51 repeatedly performs these arithmetic processes within a predetermined control cycle (for example, 100 msec) and outputs the arithmetic results to the operation control unit 53 each time.

[0083] (B. Integration of coordinate systems) In order to control the automatic operation of the slab carrier 10, it is necessary to handle the information obtained from the first point group data PG1 and the second point group data PG2 in the same coordinate system. As shown in FIG. 12, in the coordinate system (X1 - Y1 - Z1 coordinate system of the slab carrier 10; hereinafter also referred to as the "carrier coordinate system") of the slab carrier 10, the origin O1 is taken at the center in the width direction at the upper part of the front surface of the slab carrier 10, and in the coordinate system (X2 - Y2 - Z2 coordinate system of the pallet 20; hereinafter also referred to as the "pallet coordinate system") of the pallet 20, the origin O2 is taken at the center in the width direction at the scanning height position of the front surface of the pallet. The positions of these origins O1 and O2 do not match. If the position information of the slab carrier 10 with respect to the pallet 20 is obtained using the information of different coordinate systems as they are, since the position information is different from the actual position, the slab carrier 10 cannot be accurately controlled. Therefore, in the control of the automatic operation of the slab carrier 10, it is necessary to integrate the carrier coordinate system and the pallet coordinate system into one.

[0084] The coordinates of the origin O1 of the carrier coordinate system can be determined based on the installation position of the second measurement unit 32 on the carriage unit 11 and the dimensions of the slab carrier 10. Also, the coordinates of the origin O2 of the pallet coordinate system can be determined based on the position of the column portion 23 of the pallet 20 detected by the second measurement unit 32 and the dimensions of the pallet 20. By aligning the origins O1 and O2 of each coordinate system obtained and the directions of the three axes, each piece of information can be handled in the same coordinate system, and the relative information of the slab carrier 10 with respect to the pallet 20 (center-to-center distance D, steering direction misalignment amount d, yaw angle θ) can be calculated.

[0085] Here, since there is an installation error in the second measurement unit 32, the origin of the two-dimensional information of the second point cloud data PG2 acquired by the second measurement unit 32 is shifted from the origin O1 of the carrier coordinate system, and an error also occurs in the calculation result. Therefore, in advance, using a calibration unit, the amount of deviation from the origin of the slab carrier 10 at the installation position of the second measurement unit 32 is measured, and the origin of the carrier coordinate system is corrected by the amount of deviation of the second measurement unit 32. Thereby, the installation error of the second measurement unit 32 can be corrected.

[0086] The installation error of the second measurement unit 32 can be measured, for example, using a calibration unit 70 as shown in FIG. 13. The calibration unit 70 includes a reference plate 71 and a support member 73 with one side fixed to the reference plate 71 and the other side attached to the slab carrier 10. For example, if the carriage unit 11 is made of a material having a magnetic body, a magnet is provided on the contact surface of the support member 73 with the carriage unit 11, and the calibration unit 70 can be attached to the slab carrier 10 by magnetic force.

[0087] The calibration unit 70 is attached to the slab carrier 10 such that the plate surface of the reference plate 71 is parallel to the front surface of the slab carrier 10 and is included in the scanning plane of the second measurement unit 32. The distance Dc between the plate surface of the reference plate 71 and the front surface of the slab carrier 10 in the state where the calibration unit 70 is attached to the slab carrier 10 is equal to the length of the support member 73.

[0088] When the calibration unit 70 is attached to the slab carrier 10, the second measurement unit 32 scans the laser beam in the horizontal direction (X direction) to obtain a point group consisting of detection points Pm where the reference plate 71 is detected. The three-dimensional information indicated by the detection point Pm is a measured value. If there is an installation error in the second measurement unit 32, as shown in FIG. 13, the three-dimensional information of the detection point Pm deviates from the three-dimensional information of the detection point Pr when the reference plate 71 is actually detected at the front surface position of the reference plate 71. That is, the deviation amount of the three-dimensional information of the detection point Pm from the three-dimensional information of the detection point Pr is the installation error of the second measurement unit 32. From the installation error of the second measurement unit 32, the error of the center-to-center distance D, the deviation amount d of the steering direction position, and the error of the yaw angle θ are obtained in advance. When the arithmetic processing unit 51 integrates the carrier coordinate system and the pallet coordinate system in arithmetic processing, by correcting these errors, the accuracy of the arithmetic processing can be improved.

[0089] [2-3. Automatic Driving Control of Slab Carrier] Based on FIG. 14, the automatic driving control of the slab carrier 10 will be described. FIG. 14 is an explanatory diagram for explaining the automatic driving control of the slab carrier 10 according to the present embodiment, and shows a state in which the slab carrier 10 and the pallet 20 are viewed in plan.

[0090] As described above, the control unit 50 of the slab carrier 10 acquires the first point group data PG1 and the second point group data PG2 in real time by the measurement unit 30, performs arithmetic processing by the arithmetic processing unit 51, and calculates the control amount of the slab carrier 10 by the driving control unit 53 to control the driving. The control amount of the slab carrier 10 calculated by the driving control unit 53 is transmitted to a PLC (Programmable Logic Controller) mounted on the carriage unit 11, and the steering, accelerator, and brake of the carriage unit 11 are controlled.

[0091] The arithmetic processing unit 51 first executes the pallet identification process shown in FIG. 5, and identifies the pallet 20 closest to the slab carrier 10 based on the first point cloud data PG1 acquired by the measurement unit 30. Then, the arithmetic processing unit 51 processes the second point cloud data PG2 acquired by the measurement unit 30, and calculates the center-to-center distance D, which is the distance to the pallet 20, the steering direction misalignment amount d, and the yaw angle θ of the slab carrier 10 with respect to the pallet 20 at a predetermined control period (for example, a 100 msec period). Based on the information calculated by the arithmetic processing unit 51, the driving control unit 53 calculates a movement path such that the carrier center axis C1 and the pallet center axis C2 coincide and the yaw angle θ becomes 0°.

[0092] For example, when the pallet 20 to be entered is identified, assume that the carrier center line C1 of the slab carrier 10 is inclined with respect to the pallet center axis C2 of the pallet 20 to be entered, as shown in the upper part of FIG. 14. If the slab carrier 10 is advanced in this state, it will contact the pallet 20 or will not be able to enter the internal space V of the pallet. Therefore, it is necessary to correct the posture of the carriage unit 11.

[0093] Therefore, based on the center-to-center distance D, the steering direction misalignment amount d, and the yaw angle θ obtained by the arithmetic processing of the arithmetic processing unit 51, the driving control unit 53 first rotates the carriage unit 11 about the carrier center Q1 so that the yaw angle θ becomes 0°, and corrects the orientation. As a result, as shown in the center of FIG. 14, the carrier center axis C1 and the pallet center axis C2 of the slab carrier 10 become parallel. Next, the driving control unit 53 moves the carriage unit 11 in the width direction (X direction) so that the steering direction misalignment amount d becomes 0. As a result, as shown in the lower part of FIG. 14, the misalignment between the carrier center axis C1 and the pallet center axis C2 disappears, and the slab carrier 10 and the pallet 20 face each other, and the slab carrier 10 can enter the pallet 20.

[0094] When the slab carrier 10 becomes capable of entering the pallet 20, the operation control unit 53 moves the slab carrier 10 straight forward and moves the slab carrier 10 until the center-to-center distance D becomes 0. As shown in the lower part of FIG. 14, before moving the slab carrier 10 forward, by aligning the carrier center axis C1 and the pallet center axis C2 and setting the yaw angle θ to 0°, the slab carrier 10 can enter the internal space V of the pallet without contacting the pallet 20. Then, the operation control unit 53 stops the carriage unit 11 that has entered the internal space V of the pallet at the stop position where the pallet 20 is lifted.

[0095] After that, the operation control unit 53 causes the carriage unit 11 to lift the pallet 20 and moves the carriage unit 11 backward while the pallet 20 is lifted. Thus, the pallet 20 (and further the slab placed on the upper part of the pallet 20) is carried out. In this way, the slab carrier 10 is made to exit from the internal space V of the pallet.

[0096] Note that after the slab carrier 10 enters the pallet 20, the slab carrier 10 moves forward inside the internal space V of the pallet based on the center-to-center distance D obtained by processing the second point group data PG2. Here, when the length of the pallet 20 in the longitudinal direction is shorter than the length of the slab carrier 10 in the longitudinal direction, before the center-to-center distance D becomes 0, the front surface of the carriage unit 11 passes through the internal space V of the pallet. For this reason, after the front surface of the carriage unit 11 passes through the internal space V of the pallet, the measurement unit 30 can no longer detect the column portion 23 of the pallet 20, and the arithmetic processing unit 51 cannot calculate the center-to-center distance D, the steering direction positional deviation amount d, and the yaw angle θ.

[0097] Therefore, as shown in FIG. 2, by providing the inertial measurement unit 60 that measures the movement amount of the carriage unit 11 on the slab carrier 10, even if the second point group data PG2 cannot be acquired from the measurement unit 30, the movement amount of the slab carrier 10 can be acquired from the measurement result of the inertial measurement unit 60.

[0098] For example, as shown in FIG. 15, when the slab carrier 10 becomes in a state where it can enter the pallet 20, until the front surface of the carriage unit 11 passes through the internal space V of the pallet, the operation control unit 53 advances the slab carrier 10 so that the center-to-center distance D calculated based on the second point group data becomes 0. Then, when the front surface of the carriage unit 11 passes through the internal space V of the pallet, the operation control unit 53 determines whether or not the carrier center Q1 and the pallet center Q2 coincide from the amount of movement of the slab carrier 10 measured by the inertial measurement unit 60, and stops the carriage unit 11 when it is determined that the carrier center Q1 and the pallet center Q2 coincide. Thereby, even when the column portion 23 of the pallet 20 cannot be detected from the second point group data PG2 acquired by the measurement unit 30, the operation control unit 53 can stop the slab carrier 10 at the stop position.

[0099] Note that, even without using the inertial measurement unit 60, by using the speed performance signal of the slab carrier 10, the above-described operation control for stopping the slab carrier 10 at the stop position can also be performed when the second point group data PG2 cannot be acquired from the measurement unit 30.

[0100] As described above, the automatic operation of the slab carrier 10 according to the present embodiment has been described. According to the present embodiment, the slab carrier 10 uses the first point group data that is a point group of three-dimensional information of an object and the second point group data that is a point group of two-dimensional information of the object, and the control unit 50 identifies the pallet 20 to be entered and automatically enters the slab carrier 10. Thereby, the slab carrier 10 can identify the pallet 20 to be entered and automatically enter even when a plurality of pallets 20 are placed.

[0101] As described above, the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that those having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modification examples or correction examples within the scope of the technical idea described in the claims, and it is naturally understood that these also belong to the technical scope of the present invention.

[0102] For example, in the above-described embodiment, the measurement unit of the slab carrier is composed of a 3D-LiDAR and a 2D-LiDAR, and thus acquires first point cloud data which is a point cloud of three-dimensional information of an object in the scanning space and second point cloud data which is a point cloud of two-dimensional information of the object. However, the present invention is not limited to such an example. For example, the measurement unit of the slab carrier may be composed of one 3D-LiDAR. In this case, while acquiring the first point cloud data which is a point cloud of three-dimensional information by the 3D-LiDAR, it is possible to extract two-dimensional information from the three-dimensional information and acquire the second point cloud data. As a result, similar to the above-described embodiment, a pallet frame is detected from the first point cloud data which is a point cloud of three-dimensional information of an object acquired by one 3D-LiDAR, and position information of the pallet and the position and orientation of the carriage part with respect to the pallet can be obtained from the second point cloud data obtained by extracting two-dimensional information from the three-dimensional information of the object.

Explanation of Signs

[0103] 10 Slab carrier (transport device) 11 Carriage part 13 Wheels 20 Pallet 21 Mounting part 23 Column part 30 Measurement unit 31 First measurement unit (3D-LiDAR) 32 Second measurement unit (2D-LiDAR) 50 Control unit 51 Arithmetic processing unit 53 Driving control unit 60 Inertial measurement unit 70 Calibration unit 71 Reference plate 73 Support member

Claims

1. A conveying device for conveying a pallet having a placement portion on which an object to be conveyed is placed and a pair of column portions that support the placement portion, a carriage portion that enters a pallet internal space surrounded by the placement portion and the pair of column portions, and loads and conveys the pallet, a control portion that controls the conveying device, comprising: the carriage portion has a measurement portion that scans a laser beam to acquire first point cloud data that is a point cloud of three-dimensional information of an object in a scanning space and second point cloud data that is a point cloud of two-dimensional information of the object, the control portion: detects the pallet by detecting the placement portion and the pair of column portions from the first point cloud data, and calculates the position of the pallet, the position and orientation of the carriage portion with respect to the pallet based on the second point cloud data, an arithmetic processing portion; a driving control portion that causes the carriage portion to face the pallet to be entered and enter the pallet internal space based on the arithmetic processing result by the arithmetic processing portion, A conveying device having the above components.

2. The arithmetic processing portion: scans the second point cloud data corresponding to the state of the pallet in plan view with a scanning frame having a preset size, extracts a point cloud area in which the number of points in the scanning frame is equal to or greater than a threshold value, clusters the extracted point cloud areas, and obtains a column portion line indicating the position of the column portions arranged in the depth direction of the pallet from candidate point clouds included in the point cloud areas belonging to the same class, The driving control portion causes the carriage portion to enter the pallet internal space based on the column portion line corresponding to the pair of column portions obtained by the arithmetic processing portion, the position and orientation of the carriage portion, according to the conveying device of Claim 1.

3. The arithmetic processing portion: in each of the point cloud areas extracted by clustering, when the absolute value of the slope of a straight line passing through two separated points is greater than a predetermined threshold value, the two points are excluded from the point cloud of the point cloud area, The column portion line is obtained from the points included in the point cloud areas belonging to the same class from which the two points have been excluded, according to the conveying device of Claim 2.

4. The driving control portion: when the arithmetic processing portion detects one pallet from the first point cloud data, sets the pallet as the pallet to be entered by the conveying device, when the arithmetic processing portion detects a plurality of pallets from the first point cloud data, sets the pallet with the center of the carriage portion between the pair of column portions as the pallet to be entered by the conveying device, according to the conveying device of Claim 1.

5. When the operation control unit detects that the arithmetic processing unit has detected a plurality of pallets from the first point cloud data, if the center of the carriage unit is not between the pair of column units, For each of the detected pallets, calculate the intermediate position between the pair of column units, The transport device according to claim 4, wherein the pallet with the minimum distance between the carriage unit and the intermediate position is the pallet to be entered by the transport device.

6. The carriage unit has an inertial measurement unit that measures the amount of movement of the carriage unit, The operation control unit stops the carriage unit at the stop position based on the amount of movement of the carriage unit measured by the inertial measurement unit or the speed signal of the transport device after the carriage unit enters the internal space of the pallet. The transport device according to claim 1.

7. A control device for controlling a transport device for transporting a pallet, The transport device is A carriage unit that enters a pallet internal space surrounded by a pallet placement part and a pair of column parts, loads and transports the pallet, A measurement unit provided in the carriage unit that scans laser light and acquires first point cloud data that is a point cloud of three-dimensional information of an object in the scanning space and second point cloud data that is a point cloud of two-dimensional information of the object, It is provided with The control device is An arithmetic processing unit that detects the pallet by detecting the placement unit and the pair of column units from the first point cloud data acquired by the measurement unit, and calculates the position and orientation of the carriage unit with respect to the pallet from the second point cloud data acquired by the measurement unit, An operation control unit that causes the carriage unit to enter the pallet internal space facing the pallet to be entered based on the arithmetic processing result by the arithmetic processing unit, A control device comprising.

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