JP3608950B2 - Automated guided vehicle - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to an automated guided vehicle that transports articles in factories, warehouses, hospitals, offices, and the like, and more particularly to simplification of an article transfer mechanism.
[0002]
[Prior art]
FIG. 6 shows a change in the posture of the article 6 when the automatic guided vehicle transfers the article 6 using the turntable 2 and the slide arm 4. If the turntable 2 and the slide arm 4 are provided in the automatic guided vehicle, the article 6 can be transferred between arbitrary points within the range that the slide arm 4 can reach. However, as the turntable 2 rotates, the posture of the article 6 changes as shown in FIG. 6, and when the article is lowered onto the loading platform of the automatic guided vehicle, it cannot be lowered in a predetermined posture, or the article mounting table. When the article is lowered, the problem that it cannot be lowered in a predetermined posture arises.
[0003]
In order to solve this problem, an XY table is prepared in a conventional automatic guided vehicle, and a turntable, a slide arm, etc. are mounted on the table, and an error in the stop position of the automatic guided vehicle is corrected by the XY table. ing. If the XY table is not provided, it is necessary to stop the automatic guided vehicle accurately with respect to the target position.
[0004]
[Problems of the Invention]
The object of the present invention is to simplify the transfer mechanism by eliminating the conventional XY table, and to allow the article to be transferred even when the automatic guided vehicle stops at a position deviating from the predetermined stop position . The object is to prevent the article from interfering with other automatic guided vehicles or article mounting tables when the turntable or the turntable is turned.
[0005]
[Structure of the invention]
The present invention relates to an automatic guided vehicle having a telescopic arm that supports an article at a tip portion and a turntable for turning the arm, for recognizing the current position of the automatic guided vehicle in an absolute coordinate system. In addition to providing a camera for position recognition, a turning table is provided at the tip of the arm, and based on the image from the camera and teaching data so as to correct the deviation of the stop position of the automatic guided vehicle from the reference position. And a control means for determining the expansion / contraction amount of the arm, the rotation amount of the turntable, and the rotation amount of the turntable, wherein the turntable rotation amount and the turntable rotation amount are opposite to each other at the same angle. in the to and the state on the way to Shin Zhang arm to transfer destination position, the turntable and the turntable with the same angle only is rotated in the reverse direction, the turntable is rotated Also characterized in that the orientation of the turntable is constructed so as not to be changed.
[0006]
[Operation and effect of the invention]
According to the present invention , a position recognition camera for recognizing the current position of the automatic guided vehicle in the absolute coordinate system is provided, and a turning table is provided at the tip of the arm, so that the reference position of the stop position of the automatic guided vehicle Control means for determining the amount of expansion / contraction of the arm, the amount of rotation of the turntable, and the amount of rotation of the turntable based on the image from the camera and teaching data so as to correct the deviation from Here, the turning amount of the turntable and the turning amount of the turntable are set to the same angle in the opposite direction, and the turntable and the turntable are set to the same angle in the reverse direction while the arm is being extended to the transfer destination position. It is configured so that the orientation of the turning table does not change even if the turntable is rotated, so that the XY table as in the conventional example is not required, and the automatic guided vehicle Even if the stop position is deviated from the indicated reference position in teaching or the like, it is possible to perform transfer Within the turning radius of the arm. Moreover, in this invention, even if a turntable is rotated, the attitude | position of articles | goods does not go out of order. In addition, if the article is large, turning the turntable or swivel table directly above the automated guided vehicle will cause the article to protrude from the body of the automated guided vehicle, interfering with other automated guided vehicles and article mounting tables. There is a fear. Further, when the turntable or the turntable is rotated at the transfer position, there is a possibility that the arm collides with an article mounting table or the like. In the present invention, the turntable and the turntable are rotated in a state where the arm is partially expanded from the most contracted state to the transfer destination side, that is, in the middle of being extended to the transfer destination. In this way, since the turntable and the turntable are simultaneously rotated, the transfer time is short, and a large article can be rotated without interfering with the surroundings. In this specification, the turntable and the turntable are the same type, but for convenience of explanation, the cart side of the automatic guided vehicle is called a turntable, and the tip side of the arm is called a turntable. Call.
[0007]
【Example】
The embodiment will be described with reference to FIGS. FIG. 1 shows the structure of the automatic guided vehicle 8, 2 is a turntable, 4 is a three-stage slide type slide arm, and a lifter 12 is mounted on a turntable 10 provided near the tip of the lifter 12. A mounting table 14 is provided at the top. Instead of the slide arm 4, a scalar arm may be used. Reference numeral 16 denotes a CCD camera provided at the tip of the slide arm 4. The lifter 12 may be provided on the turntable 2 side, for example. Reference numeral 17 denotes a mark provided on the article table 20. When the slide arm 4 expands and contracts, the CCD camera 16 recognizes the mark 17, and a fixed absolute coordinate system with the article table 20 as a reference and the automatic guided vehicle 8 side. It is used to perform coordinate conversion with the coordinate system. The mark 17 is preferably provided near the automatic guided vehicle 8 in the concave portion 21 of the article table 20 so that the slide arm 4 can be recognized in the initial state.
[0008]
18 is a loading platform of the automatic guided vehicle 8, for example, four sets are provided to place the articles 6 thereon. Reference numeral 21 denotes a recess of the article table 20. The article 6 is placed on the upper part, the slide arm 4 is inserted into the recess 21, and the article table 14 is lifted by the lifter 12, thereby lifting the article 6 from the article table 20. Note that the structure of the turntable 2 and the turning table 10 or the structure of the three-stage slide arm 4 are known, and the description thereof is omitted.
[0009]
FIG. 2 shows a control system such as the turntable 2. Reference numeral 24 denotes a control processing unit, which includes a current position recognition unit 25, a teaching data storage unit 26, and a control unit 27, and is based on an image taken by the CCD camera 16. The current position of the automatic guided vehicle 8 in the absolute coordinate system is recognized. Based on the recognized current position and the teaching data (absolute coordinate system data) stored in the teaching data storage unit 26, the control unit 27 determines the operation amounts of the turntable 2, the slide arm 4, and the turning table 10. Here, when the rotation amount of the turntable 2 is θ, the rotation amount of the turntable 10 is −θ, and the expansion / contraction amount of the slide arm 4 is Δr. Note that the amount of lift of the lifter 12 is used as it is without correction of the value of the teaching data. However, when the change in the relative height of the mark 17 with respect to the CCD camera 16 can be detected, the amount of lift of the lifter 12 can also be corrected. .
[0010]
When the state of the automatic guided vehicle 8 during the transfer operation is shown in FIG. 3, it is necessary to rotate the turntable 2 unless the automatic guided vehicle 8 stops just beside the article 6. If the turntable 2 is rotated with the slide arm 4 returned, there is a risk of interference with the surroundings if the article 6 is large as shown. Therefore, when the turntable 2 is rotated in a state where the slide arm 4 is slightly extended toward the article table 20, there is no possibility of interference with the surroundings. Here, when the article 6 is placed on the placing table 14 when the turntable 2 is rotated, the turning table 10 is also rotated by the same angle in the opposite direction so that the posture of the article 6 is not changed.
[0011]
FIG. 4 shows a control algorithm at the time of loading. The automatic guided vehicle 8 stops near the teaching position with respect to the article 6 to be loaded, and extends the slide arm 4 toward the concave portion 21 to recognize the current position. That is, the current position of the automatic guided vehicle 8 as seen in the absolute coordinate system is recognized from the image of the mark 17 photographed by the CCD camera 16. The teaching data is stored in, for example, an absolute coordinate system, and the turntable is determined from the difference between the teaching position for loading the article 6 in the absolute coordinate system and the current position of the automatic guided vehicle 8 in the absolute coordinate system. The amount of rotation necessary for 2 and the amount of expansion and contraction necessary for the slide arm 4 are determined. In the embodiment, the turning table 10 is always rotated in the opposite direction to the turntable 2 by the same angle. However, the turning table 10 is turned in the opposite direction to the turntable 2 only when the article 6 is placed on the placing table 14. You may make it rotate only the same angle.
[0012]
In this way, when the placing table 14 comes to a position directly below the article 6, the placing table 14 is raised by the lifter 12, and the article 6 is lifted from the article table 20. Next, the slide arm 4 is partially returned, the CCD camera 16 at the tip of the slide arm 4 comes out of the recess 21 and the slide arm 4 is slightly extended, and the turntable 2 and the turntable 10 are reversed. Then, the slide arm 4 is completely returned to the same angle, and the article 6 is moved to a position just above the four loading platforms 18. Thereafter, when the lifter 12 is driven to lower the mounting table 14, the article 6 is lowered onto the four loading platforms 18.
[0013]
FIG. 5 shows a control algorithm at the time of unloading. First, by lifting the lifter 12, the article 6 is lifted by the mounting table 14, then the slide arm 4 is partially extended, and the mark 17 is recognized by the CCD camera 16. As a result, the current position of the automatic guided vehicle 8 in the absolute coordinate system is recognized, and the necessary rotation amount of the turntable 2 and expansion / contraction amount of the slide arm 4 from the difference from the unloading position in the absolute coordinate system stored at the time of teaching. To decide. In this state, the slide arm 4 extends slightly toward the article table 20, and there is no risk of collision even if the article 6 is rotated here. Therefore, the turntable 2 is rotated by θ, and the turning table 10 is simultaneously rotated by −θ in order to prevent the change of the posture of the article 6. Next, the slide arm 4 is extended by the length determined by the control processing unit 24, the lifter 12 is lowered, and the article 6 is unloaded so as to straddle the left and right of the recess 21. Thereafter, when the slide arm 4 is returned, the unloading is completed.
[0014]
In the embodiment, the article can be accurately transferred from the rough stop position without the XY table. In addition, the posture of the article can be constantly maintained, and transfer is simplified. Even when a large article is transferred, there is no interference with the surroundings.
[Brief description of the drawings]
FIG. 1 is a rear view of an automatic guided vehicle according to an embodiment with a slide arm extended. FIG. 2 is a block diagram of a control system of the automatic guided vehicle according to the embodiment. [Fig. 4] Flow chart of loading control of the automated guided vehicle of the embodiment [Fig. 5] Flow chart of control of the automatic guided vehicle of the embodiment when unloading [Fig. 6] Rotating the turntable Showing the change in the posture of an article accompanying the movement [Explanation of symbols]
2 turntable 4 slide arm 6 article 8 automatic guided vehicle 10 turning table 12 lifter 14 mounting table 16 CCD camera 17 mark 18 loading platform 20 article table 21 recess 24 control processing unit 25 current position recognition unit 26 teaching data storage unit 27 control unit

Claims (1)

In an automatic guided vehicle including a telescopic arm that supports an article at a tip portion and a turntable for turning the arm,
In addition to providing a camera for position recognition to recognize the current position of the automated guided vehicle in the absolute coordinate system,
A swivel table is provided at the tip of the arm,
Based on the image from the camera and the teaching data, the amount of expansion / contraction of the arm, the amount of rotation of the turntable, and the amount of rotation of the turntable so as to correct the deviation of the stop position of the automatic guided vehicle from the reference position Control means is provided for determining the rotation amount of the turntable and the rotation amount of the turntable at the same angle in the opposite direction ,
In addition, while the arm is being extended to the transfer destination position, the turntable and the turntable are rotated in the opposite direction by the same angle so that the direction of the turntable does not change even if the turntable rotates. An automatic guided vehicle characterized in that it is configured as follows.

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