JP7353575B2 - Pallet transport system - Google Patents

Description

The present invention relates to a pallet transport system used when transporting pallets for cargo handling using an unmanned transport vehicle.

For example, in a manufacturing facility such as a steelworks, there is a method of transporting cargo together with the pallet by entering a transport vehicle into the space below a pallet for cargo handling and lifting the pallet. An example of this method is described in Patent Document 1.

Regarding a method for guiding an unmanned guided vehicle to the space below a pallet, Patent Document 1 discloses that in order to detect the relative position and angle of the pallet with respect to the vehicle body, a laser beam is emitted from a sensor attached to the vehicle body to the pallet. By irradiating the pillars on both legs of the machine, the internal position of the pillars is detected by obtaining a data group of measurement points that are in an opposing relationship, and based on this, the pallet The direction of both legs and the center line of both legs are calculated. Note that the column portion has a rigid frame structure or a truss structure using section steel (such as H section steel).

Patent No. 4427360

However, in the above method, for example, if the transport vehicle stops diagonally before approaching the pallet and the inner part of the column is in the shadow of the laser beam, the data groups in the opposing relationship are As a result, the internal position of the column cannot be detected, and as a result, the direction of both legs of the pallet and the center line of both legs cannot be calculated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pallet transport system that reduces the occurrence of situations in which the position of a pallet cannot be detected.

The present invention provides a transport vehicle that is arranged below the loading platform of a pallet and has a loading platform and a pair of legs that support the loading platform from below with an interval in the width direction, and moves the pallet while lifting it off the ground. In the pallet transport system, the transport vehicle includes an irradiating unit that irradiates the pair of legs with detection light, and a light receiving unit that receives reflected light that is the detection light reflected by the pair of legs. , a data collection step of acquiring a plurality of detection data by irradiating the pair of legs with the detection light from the irradiation section and receiving the reflected light at the light reception section; a starting point data setting step of setting single starting point data for each of one leg and the other leg of the pair of legs; For each of the side legs, out of the plurality of detection data including the origin data, the end data is searched for the end data point located at the end of the opposing surface of the pair of legs with respect to the transport vehicle. a searching step, a pallet position deriving step of deriving the center position of the pair of legs using the endmost data point of each of the one side leg and the other side leg, and the derived pair of legs. This is a pallet transport system that carries out a transport vehicle moving step of moving the transport vehicle in accordance with the center position of the pallet.

According to this configuration, the center position of a pair of legs is derived and the guided vehicle is moved to that position, without detecting the inner position of the legs by obtaining data groups that are in an opposing relationship as in the past. It can be moved.

Further, in the present invention, the search in the edge data searching step is performed by sequentially recognizing individual detection positions of the plurality of detection data inward or outward, and the recognition is performed in the data collecting step. This can be done based on the scanning interval at .

According to this configuration, by performing the search in the extreme data searching step based on the scanning interval in the data collecting step, it is possible to suppress erroneous recognition influenced by unrelated noise.

Further, the present invention provides the data collection method for one of the pair of legs located halfway in the depth direction of the pallet while the conveyance vehicle is entering below the loading platform of the pallet. Each step after this step can be performed.

According to this configuration, it is possible to improve the accuracy of the approach while the transport vehicle is entering below the loading platform on the pallet.

In the present invention, the center position of a pair of legs can be guided and the carrier can be moved to that position without detecting the inner position of the legs as in the conventional method. On the other hand, even when the vehicle is stopped diagonally, it is possible to reduce the occurrence of situations in which the position of the pallet cannot be detected.

It is a left side view showing an example of a pallet used in a pallet conveyance system concerning one embodiment of the present invention. It is a front view showing an example of the pallet together with a transport vehicle (indicated by a two-dot chain line). It is a schematic diagram for explaining the data collection process in the same pallet conveyance system. 4 is an enlarged view of the right leg of the pallet in FIG. 3. FIG. It is a flowchart which shows each process after a target area setting process in the same pallet conveyance system.

One embodiment of the pallet conveyance system of the present invention will be described below with reference to the drawings.

The pallet transport system of this embodiment is a system using a transport vehicle 2 that moves the pallet 1 while lifting it off the ground while being placed below a loading platform 11 that the pallet 1 has. In addition, when controlling the transport vehicle 2 remotely, a control unit (not shown) is provided at a position away from the transport vehicle 2.

First, a pallet 1, which is an object to which the pallet conveyance system of this embodiment is applied, will be described. As shown in FIGS. 1 and 2, the pallet 1 includes a loading platform 11 on which cargo can be loaded, and a pair of legs 12 that support the loading platform 11 from below at intervals in the width direction (left-right direction in FIG. 2). has. As shown in FIG. 2, the pair of legs 12 in this embodiment face each other with an interval left and right. Each of the pair of leg sections 12 (each leg section 12) has a plurality of column sections 121 extending in the vertical direction and a leg bottom section 122 that connects the plurality of column sections 121 below. In this embodiment, each column 121 extends in the vertical direction (perpendicular to the ground of the pallet storage area Y), and the loading platform 11 and each leg 12 form a rigid frame structure. However, the present invention is not limited to this, and each column portion 121 may extend in an oblique direction. In this case, the structure will be a rigid frame structure or a truss structure. As shown in FIG. 2, the pallet 1 of this embodiment has a so-called "gate-shaped" shape, and a space 11S is formed below the loading platform 11.

The transport vehicle 2 is generally called a "carrier pallet vehicle" and is formed at a vehicle height that allows it to be placed so as to enter the space 11S that exists below the loading platform 11 on the pallet 1 (indicated by the chain double-dashed line in FIG. 2). ). By increasing the height of the vehicle, the pallet 1 can be moved while being lifted off the ground. This conveyance vehicle 2 has a driver's cab at both front and rear ends and can be operated by a man, but when used in the pallet conveyance system of this embodiment, the conveyance vehicle 2 is mainly operated unmanned. However, the pallet conveyance system of this embodiment may be applied as an auxiliary during manned travel. The conveyance vehicle 2 includes an irradiation unit 21 that irradiates detection light toward the pallet 1 (more specifically, each leg 12 of the pallet 1) located at an opposing position, and an irradiation unit 21 that irradiates detection light toward the pallet 1 (specifically, each leg 12 of the pallet 1), and a It has a light receiving section 22 that receives light. As the irradiating section 21 and the light receiving section 22, various sensors that perform detection by emitting and receiving light beams can be used. The two-dot chain line shown in FIG. 3 corresponds to the detection light and the reflected light. At least the irradiation unit 21 performs scanning by rotating around an axis that extends vertically with respect to the vehicle body of the transport vehicle 2 (for example, rotating in the direction R).

A pair of legs 12 (more specifically, pillars 121 of the legs 12) on the pallet 1 are connected to the carrier 2 when the carrier 2 is placed on the front side of the pallet 1 (see FIG. 1). It has facing surfaces 1211 that face each other. The column portion 121 in each leg portion 12 of this embodiment is formed from H-beam steel. A plane that is the outer surface of the front flange of the H-shaped steel serves as the opposing surface 1211.

Next, a plurality of processes performed in the pallet conveyance system of this embodiment will be explained with reference to FIG. 5 (flow diagram). First, the guided vehicle 2 is placed in the pallet yard Y by comparing the preset map data of the pallet yard Y with the route data (history data of the traveling route) that the guided vehicle 2 has traveled in the pallet yard Y. The pallet 1 is stopped in front of the pair of legs 12 on the pallet 1. The movement of the guided vehicle 2 up to this stop may be performed autonomously by a control section provided on the vehicle, or may be performed by receiving instructions, for example, wirelessly, from a control section provided outside the vehicle.

In the pallet transport system of this embodiment, before the transport vehicle 2 enters below the loading platform 11 on the pallet 1 (before the front end of the transport vehicle 2 touches the front end of the pair of legs 12), the main Next, a target area setting process, a data collection process, a starting point data setting process, a detection position recognition process, a pallet position derivation process, and a carrier movement process are performed in order. In addition to these steps, other auxiliary steps may also be performed. These steps are carried out autonomously by a control unit installed on the vehicle. Alternatively, the operation is performed by a control section provided outside the vehicle, and the operation is performed on the vehicle by receiving instructions from the control section outside the vehicle, for example, wirelessly.

In the target area setting step, the pair of legs 12 of the pallet 1 are determined by comparing the preset map data of the pallet storage area Y with the route data (traveling route history data) of the conveyance vehicle 2 in the storage area. A target area that is estimated to exist is set for each leg 12 (in this embodiment, the left and right legs 12 when viewed from the transport vehicle 2) (step S1). In addition to the above method, the target area can also be set by image recognition using a camera provided on the carrier vehicle 2.

In the data collection process, detection light is irradiated from the irradiation unit 21 of the transport vehicle 2 to a target area where the pair of legs 12 on the pallet 1 is estimated to exist, and the reflected light is received by the light receiving unit 22 of the transport vehicle 2. A plurality of detection data (detection data group) is acquired by performing scanning (step S2). Note that noise data may be mixed in the detection data acquired in the data collection step. This noise data is removed in a later process. As shown by a plurality of two-dot chain lines in FIG. 3, the scanning intervals (angular intervals) in the data collection process are equal. In FIGS. 3 and 4, the detected data group is schematically shown in a circle. Laser light is used as the detection light. However, the detection light is not limited to laser light, and may be other types of light rays.

In the starting point data setting process, from the detection data group acquired in the data collection process, one leg (for example, the right leg when viewed from the transport vehicle 2) 121R and the other leg of the pair of legs 12 are determined. (For example, the left leg when viewed from the transport vehicle 2) 121L, single starting point data (data points S, S') are set. Regarding the setting of single starting point data, it is sufficient to select one arbitrary detection data from the detection data group for each leg 12R, 12L. For this selection, for example, the distance from the irradiation section 21 and the light receiving section 22 (sensor) can be based on being within a predetermined range.

In this embodiment, as shown in FIG. 5, a starting point data setting step (step S3) and an end data searching step (steps S4 to S9) to be described later are first performed on the one side leg 12R, and then the other side leg 12R is A starting point data setting step (step S10) and an end data searching step (steps S11 to S16), which will be described later, are performed for the side leg portion 12L.

In the edge data search step, starting from the data points S and S' on each leg 12R and 12L related to the detection position of each starting point data set in the starting point data setting step, one leg 12R and the other leg are searched. In each of the sections 12L, the endmost data point located at the end of the facing surface 1211 in each leg 12R, 12L is searched from among the plurality of detection data including the starting point data. Specifically, by performing a search that sequentially recognizes the detection position of each detection data in the detection data group inward or outward in the opposite direction of each leg 12R, 12L, the innermost end or the outermost end Obtain the edgemost data point located at the edge. In this embodiment, recognition is performed inward as shown in the direction of arrow T in FIG. 4, and the endmost data point located at the innermost end is obtained. In this edge data searching step, recognition of sequentially moving inside or outside the detection position of a plurality of detected data when searching for the edge data point is performed based on the scanning interval in the data collection step. In other words, the recognition interval matches the scanning interval in the data collection process. Thereby, it is possible to suppress erroneous recognition influenced by irrelevant noise, that is, data mixed in without actually being collected in the data collection process.

In this embodiment, first, interval values of detected data near the data point related to the starting point data are calculated (steps S4, S11). Then, the data point number is set to 1 (steps S5, S12). Thereby, the point on each leg 12R, 12L related to the detection position of each starting point data becomes a "first data point."

Then, it is determined whether or not there is detection data in the vicinity of a position spaced from the first data point by the distance value in the inner direction of the pallet 1 (steps S6 and S13). If there is detected data, the data point related to the detected data is set as the second data point (steps S7, S14), and the number of the data point is set to 2 (steps S8, S15). This is repeated until there is no more detected data in the inner direction of the pallet 1, and the data points A and A' in the last detected data are set as the outermost data points (innermost data points) (steps S9, S16). Note that when it is determined that the initially set starting point data is the innermost data point, the starting point data is set as the outermost data point (innermost data point).

In the pallet position derivation step, among the detection positions of the plurality of detection data recognized in the end data search step, the innermost end (data points A, A' in this embodiment) or the end point related to the end data of the search result is selected. Using the pair of detection positions that are the outer ends, the center position C of the pair of legs 12 is derived (step S17). The “innermost end or outermost end” is the innermost end or outermost end of the plurality of detection data arranged in a substantially straight line direction in each of the one side leg portion 12R and the other side leg portion 12L. . Further, in this embodiment, the "substantially linear direction" is a direction along the line L shown by a dashed line in FIG. 3, and is a direction along the opposing surface 1211 (the outer surface of the front flange of the H-section steel). In this way, since the pallet position derivation step is performed along the opposing surfaces 1211 of the legs 12R and 12L, even if the conveyance vehicle 2 stops diagonally with respect to the pallet 1 before entering the pallet 1, However, since there are always detection positions of a plurality of detection data along the opposing surfaces 1211 of the legs 12R and 12L, it is not impossible to derive the center position C of the pair of legs 12. Note that the pair of detection positions, which are the innermost end or the outermost end, have a point-to-point relationship. For this reason, there is no opposing relationship (multiple points versus multiple points) as in the past.

In this embodiment, the middle point between the innermost data points A and A' set in each leg 12 is set as the center position C of the pallet 1, and a line perpendicular to the line segment connecting each data point A and A' Let the direction of the center line CL, which is the minute, be the direction of the center line of the pallet 1 (that is, the inclination of the pallet 1 with respect to the transport vehicle 2).

In the carrier moving process, the carrier 2 is moved in accordance with the center position C and center line CL of the pair of legs 12 obtained in the pallet position deriving process.

As described above, since the carrier 2 is moved relative to the pallet 1, according to the present embodiment, the center of the pair of legs 12 is It is possible to guide the position C and move the carrier 2 to that position.

Although the present invention has been described by taking up one embodiment, the present invention is not limited to the embodiment described above, and various changes can be made without departing from the gist of the present invention.

For example, while the transport vehicle 2 is entering below the loading platform 11 on the pallet 1, the data collection step It is also possible to carry out each of the subsequent steps in layers. By doing this, the guided vehicle 2 can be moved to match the center position C of the pair of legs 12 even while the guided vehicle 2 is approaching, so if the guided vehicle 2 is moved to the center position C of the pair of legs 12 during the approach. Even if it deviates from position C, it is corrected there, so that a situation where the transport vehicle 2 rubs against the leg portion 12 during the approach does not occur. Therefore, it is possible to improve the accuracy of the approach while the transport vehicle 2 is entering below the loading platform 11 on the pallet 1.

Further, in the embodiment, in the endmost data searching step, the detection position of each detection data in the detection data group was recognized in order toward the inner side of each leg 12R, 12L. However, it is also possible to recognize things outwards in order. In this case, as can be understood from FIG. 3, no data points appear in the vicinity of the data points B and B' in the outermost detection data except for the facing surface 1211. This is because the detection light is blocked by the opposing surface 1211 and does not hit the outer portions of the legs 12R and 12L (between the flanges of the H-section steel). Therefore, by performing recognition outwards in order, the possibility of false detection can be reduced.

Furthermore, in the edge data search process, recognition is performed on both the inner and outer sides, an intermediate position between the innermost data point position and the outermost data point is derived, and this intermediate position is The pallet position derivation process can also be carried out using .

Further, in the pallet 1 of the embodiment, the column portions 121 in each leg portion 12 were formed from H-beam steel. However, the material is not limited to this, and various materials can be used as long as they have a facing surface 1211 facing the transport vehicle 2. For this reason, the column portion 121 may be made of, for example, a square steel pipe, a channel material, or an angle material. Furthermore, even if a circular steel pipe is used for the column part 121 and a flat plate is attached to the side surface of the part that receives the detection light irradiated from the irradiation part 21 of the transport vehicle 2, and the surface of this flat plate is used as the opposing surface 1211. good.

1 Pallet 11 Loading platform 12 Leg 12L Other side leg (left leg)
12R One side leg (right leg)
121 Column portion 1211 Opposing surface 122 Leg bottom portion 2 Transport vehicle 21 Irradiation portion 22 Light receiving portion C Center position of a pair of legs CL Center line

Claims (3)

In a pallet transport system using a carrier that moves the pallet while floating the pallet from the ground while being placed below the loading platform of a pallet having a loading platform and a pair of legs that support the loading platform from below with an interval in the width direction. ,
The transport vehicle includes an irradiation unit that irradiates the pair of legs with detection light, and a light reception unit that receives reflected light that is the detection light reflected by the pair of legs,
By irradiating the pair of legs with the detection light from the irradiation unit and receiving the reflected light at the light receiving unit , a plurality of pieces of detection data that are continuous in the inner and outer directions with respect to the pair of legs are acquired. data collection process;
a starting point data setting step of setting single starting point data for each of one leg and the other leg of the pair of legs from the plurality of detection data;
Using each of the set starting point data as a starting point, each of the one side leg section and the other side leg section determines, from among the plurality of detection data including the starting point data, the direction of the pair of legs with respect to the transport vehicle. an edge data search step of searching for an edge data point located at the edge of the surface;
a pallet position deriving step of deriving the center position of the pair of legs using the endmost data points of each of the one side leg and the other side leg;
A conveyance vehicle moving step of moving the conveyance vehicle in accordance with the center position of the guided pair of legs is performed, thereby forming a data group in which a plurality of measurement points are collected and in a facing relationship. By obtaining a data group, the inner position of the leg is detected, and the direction of both legs of the pallet and the center line of both legs are calculated based on the detection result. A pallet transport system that moves transport vehicles . The search in the edge data search step is performed by sequentially recognizing individual detection positions of the plurality of detection data inward or outward,
The pallet conveyance system according to claim 1, wherein the recognition is performed based on a scanning interval in the data collection step. While the conveyance vehicle is entering below the loading platform on the pallet, each step after the data collection step is performed on one of the pair of legs that is located halfway in the depth direction of the pallet. A pallet conveyance system according to claim 1 or 2, wherein the pallet conveyance system is implemented.

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