JP6541200B1 - Misalignment detection system for moving object - Google Patents

Abstract

The present invention provides a displacement amount detection system capable of detecting various displacement amounts of a movable body with respect to a target with high accuracy while using a simple configuration with a small number of sensors.
A displacement amount detection system according to the present invention is a displacement amount based on outputs of a detection surface (21) provided on a target side, sensors (54, 55) provided on a movable body side, and sensors (54, 55). And a displacement amount calculation unit 60A that calculates the amount. The sensor 53 is provided at a position where the light L1 is applied to the convex portion 22 when stationary, and the sensor 55 is provided at a position where the light L2 is not applied to the convex portion 22 when stationary. The positional deviation amount calculation unit 60A calculates the position related to the rotation around the Z axis based on the distance a1 calculated from the output of the sensor 54 regarding the portion other than the convex portion 22 and the distance a2 calculated from the output of the sensor 55. The deviation amount Gθ is calculated.
[Selected figure] Figure 3

Description

  The present invention relates to a displacement amount detection system that detects the amount of stationary displacement of a movable body movable on the floor with respect to a target installed on the floor.

  Conventionally, in an unmanned factory or the like, (1) an unmanned transport vehicle as a moving body moves close to a loading platform as a target and stands still, (2) the unmanned transport vehicle receives a package from the loading platform, (3) luggage The unmanned transport vehicle which has received the move to the vicinity of another loading platform and comes to rest, (4) the unmanned transport vehicle automatically delivers the load to the loading platform. In such a so-called unmanned transfer system, high-precision alignment of the moving body with the target is required in order to reliably and accurately receive and deliver the load.

  Although it is not an unmanned conveyance system, as a prior art regarding the alignment with respect to a target, there exists a system of patent document 1, for example. This system is configured to detect parallelism of the fork relative to the pallet as a target by two ultrasonic displacement sensors on the left and right, and to detect lateral displacement of the fork relative to the pallet by two optical position sensors on the left and right. .

Japanese Patent Application Laid-Open No. 10-291797

  However, the above-mentioned conventional system requires (1) four sensors to be prepared in order to detect two types of positional deviation. (2) Accuracy of positional deviation amount related to rotation detected by an ultrasonic displacement sensor There are various problems such as (3) the presence or absence of lateral displacement can be detected, but the amount can not be detected.

  The present invention has been made in view of the above circumstances, and it is a simple configuration with a small number of sensors, yet can detect displacement amounts of various types of displacement of the movable body with respect to the target with high accuracy. To provide a system.

  In order to solve the above-mentioned subject, the position shift amount detection system concerning the present invention detects the amount of position shift at the time of stationary of the mobile movable on the floor with respect to the target installed on the floor. A detection system comprising: a detected surface provided on a target side perpendicular to a floor; first and second sensors provided on a moving body; and positions based on outputs of the first and second sensors. A displacement amount calculating unit for calculating the displacement amount, the detected surface includes at least one concave / convex portion, and the first sensor and the second sensor emit light in a line parallel to the floor And a two-dimensional displacement sensor that detects the reflected light corresponding to the light and outputs the reflected light, and the first sensor is such that the light of the first sensor is applied to at least a part of the concave / convex portions when stationary. Set in position The second sensor is provided at a position away from the first sensor in the direction parallel to the floor such that the light of the second sensor does not fall on the concave / convex portions when stationary. Among the sensor outputs, the distance between the first sensor and the surface to be detected, which is calculated from the non-concave / convex portions, and the second sensor to be detected, which is calculated from the output of the second sensor And calculating the amount of displacement regarding rotation about the normal to the floor based on the distance.

  The position shift amount calculation unit of the position shift amount detection system further determines, based on the position of the concave / convex portion specified from the output of the first sensor, the position shift in the direction substantially parallel to both the floor and the detected surface. It is preferred to calculate the amount.

  Further, the position shift amount calculation unit of the position shift amount detection system corrects and corrects the calculated distance between the first sensor and the surface to be detected in accordance with a rule regarding linearity accuracy of the first sensor. It is preferable to calculate the amount of positional deviation related to the rotation around the normal of the floor based on the later distance and the calculated distance between the second sensor and the detected surface.

  Further, the moving body of the positional displacement amount detection system is, for example, an unmanned transport vehicle, and the target is, for example, a loading platform on which a load to be transported by the unmanned transport vehicle is placed.

  According to the present invention, it is possible to provide a positional deviation amount detection system capable of detecting various positional deviation amounts of a moving body with respect to a target with high accuracy while using a simple configuration with a small number of sensors.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic plan view which shows the whole unmanned conveyance system in which the position shift amount detection system which concerns on 1st Example of this invention was integrated. It is the top view and side view which show a part of unmanned conveyance system incorporating the positional offset amount detection system which concerns on 1st Example. FIG. 1 is a diagram showing a displacement amount detection system according to a first embodiment. It is a figure which shows the data group output from the 1st sensor shown in FIG. 3, and a 2nd sensor. It is a figure for demonstrating the operation | movement of the 1st position shift amount calculation part shown in FIG. It is a figure which shows the displacement amount detection system which concerns on 1st Example (however, the aspect of displacement is different from FIG. 3). It is a figure which shows the misregistration amount detection system which concerns on 2nd Example of this invention. It is a figure for demonstrating the operation | movement of the 1st distance correction part shown in FIG.

  Hereinafter, an embodiment of a displacement amount detection system according to the present invention will be described with reference to the attached drawings.

[First embodiment]
FIG. 1 shows an unmanned transfer system 10 in which a displacement amount detection system according to a first embodiment of the present invention is incorporated. As shown in the figure, the unmanned transfer system 10 is provided along a substantially annular guiding line 12 laid on the floor 11, three loading platforms 20, 30 and 40 installed on the floor 11, and the guiding line 12. The four unmanned transfer vehicles AGV1, AGV2, AGV3 and AGV4 moving on the floor 11 are provided. In the present embodiment, the unmanned transfer vehicles AGV 1, AGV 2, AGV 3, AGV 4 transport the load W received from the first loading platform 20 or the second loading platform 30 to the third loading platform 40. In the present embodiment, the loading platforms 20, 30, 40 correspond to the "target" of the present invention, and the unmanned transfer vehicles AGV1, AGV2, AGV3, AGV4 correspond to the "mobile" of the present invention.

  FIG. 2 shows the first loading platform 20 and the first unmanned transfer vehicle AGV1 stationary near the first loading platform 20 for receiving the load W. As shown in the figure, the first loading platform 20 includes a detection surface 21 perpendicular to the floor 11, and the detection surface 21 includes a protrusion 22. The first unmanned transfer vehicle AGV1 is provided between the main body 50 having the plurality of wheels 51 at the lower portion, the transfer device 53 responsible for receiving / delivery of the load W, the main body 50, and the transfer device 53. The transfer correction mechanism 52, a first sensor 54 and a second sensor 55 directed to the first loading platform 20, and a positional deviation calculation unit 60A housed in the main body 50 are provided. The displacement amount detection system according to the present embodiment is configured of the detection surface 21, the first sensor 54, the second sensor 55, and the displacement amount calculation unit 60A among them.

  In the following, a plane parallel to the floor 11 is referred to as an XY plane, and a plane parallel to the detection surface 21 is referred to as an XZ plane. Further, in the vicinity of the first loading platform 20, when the guide line 12 extends in the X direction and the displacement amount of the first unmanned transfer vehicle AGV1 with respect to the first loading platform 20 is zero, the first sensor 54 and the second sensor 55 And X direction only.

  The first sensor 54 and the second sensor 55 emit linear light L1 and L2 parallel to the floor 11 (XY plane) and detect reflected light corresponding to the emitted light L1 and L2, and the reflected light Is an optical reflection type two-dimensional displacement sensor that outputs data relating to the position shift amount calculation unit 60A. As shown in FIG. 2A, when the first unmanned transfer vehicle AGV1 is stationary, the first sensor 54 is positioned more specifically such that the light L1 is applied to the convex portion 22 of the detection surface 21. The light L 1 is provided at a position where it crosses the convex portion 22. On the other hand, the second sensor 55 is provided at such a position that the light L2 does not fall on the convex portion 22 when the first unmanned transfer vehicle AGV1 is stationary.

  The misregistration amount calculation unit 60A detects the misregistration amount of the first unmanned transfer vehicle AGV1 with respect to the first loading platform 20 based on the data output from the first sensor 54 and the second sensor 55, and detects the misregistration amount. Are outputted to the transfer correction mechanism 52. Then, the transfer correction mechanism 52 extends toward the loading box 20 based on the positional deviation amount, and the position of the transfer device 53 (based on the main body 50) including an arm or the like that receives / delivers the load W. Correct relative position) and motion. Thereby, the positional deviation of the first unmanned transfer vehicle AGV1 with respect to the first loading platform 20 is canceled, and reliable and accurate reception / delivery of the package W becomes possible.

  Although described in detail later, the positional deviation calculation unit 60A calculates the positional deviation related to rotation around the normal line (Z axis) of the floor 11 (hereinafter referred to as “first positional deviation amount Gθ”), An amount of positional deviation (hereinafter referred to as “second positional deviation amount GX”) in a direction (X direction) substantially parallel to both the floor 11 and the detected surface 21 is calculated. The first displacement amount Gθ and the second displacement amount GX respectively correspond to the parallelism and the lateral displacement in the prior art described above.

The procedure until the positional deviation amount is canceled is as follows.
(1) The first unmanned transfer vehicle AGV1 stands still near the first loading platform 20.
(2) The first sensor 54 and the second sensor 55 start irradiation of the lights L1 and L2.
(3) Based on the data output from the first sensor 54 and the second sensor 55, the positional deviation amount calculation unit 60A detects the positional deviation amount of the first automated guided vehicle AGV1 with respect to the first loading platform 20.
(4) The transfer correction mechanism 52 corrects the position and operation of the transfer device 53 based on the detected positional displacement amount.

  Subsequently, the operation of the misregistration amount calculation unit 60A will be described in more detail with reference to FIGS. 3 to 6.

  As shown in FIG. 3 and the like, the positional deviation amount calculation unit 60A includes a first distance calculation unit 61, a second distance calculation unit 62, a first positional deviation amount calculation unit 63, and a second positional deviation amount calculation unit 64. And. The first distance calculation unit 61 is connected to the first sensor 54 and the first displacement amount calculation unit 63, and the second distance calculation unit 62 is connected to the second sensor 55 and the first displacement amount calculation unit 63. There is. In addition, the second positional deviation amount calculation unit 64 is connected to the first sensor 54. Although not shown, the first misregistration amount calculation unit 63 and the second misregistration amount calculation unit 64 are also connected to the transfer correction mechanism 52.

  The first distance calculation unit 61 sets the convex portion 22 of the n pieces of data D11, D12,..., D1 n constituting the data group P1 (see FIG. 4A) obtained by the first sensor 54. The distance between the first sensor 54 and the surface to be detected 21 (hereinafter, referred to as “first distance a1”) is calculated using what is included in the non-overlapping regions P11 and P13. More specifically, the first distance calculation unit 61 calculates the first distance a1 by averaging the distances between the first sensor 54 and the detected surface 21 indicated by the data included in the regions P11 and P13. . At this time, the first distance calculation unit 61 may use a part of data included in the regions P11 and P13 instead of all of the data.

  The second distance calculation unit 62 uses the n pieces of data D21, D22,..., D2n constituting the data group P2 (see FIG. 4B) obtained by the second sensor 55 to generate a second sensor The distance between the sensor surface 55 and the detection surface 21 (hereinafter, referred to as “second distance a2”) is calculated. More specifically, the second distance calculation unit 62 calculates the second distance a2 by averaging the distances between the second sensor 55 and the detected surface 21 indicated by each data included in the data group P2. At this time, it is preferable that the second distance calculation unit 62 use all the data included in the data group P2.

  In the present embodiment, n is 631. It should be noted that FIG. 4 is a schematic diagram, and the number of n is not accurately represented.

ここで、ｂは、第１センサ５４の中央および第２センサ５５の中央の間の距離である。本実施例では、ｂは３５０ｍｍである。また、被検知面２１に到達したときの光Ｌ１，Ｌ２のＸＹ平面上での拡がりは、それぞれ約１８．９２５°である。 The first misregistration amount calculation unit 63 calculates a first misregistration amount Gθ based on the calculated first distance a1 and second distance a2. More specifically, the first misregistration amount calculation unit 63 calculates the first misregistration amount Gθ using the following equation derived from FIG. 5.

Here, b is the distance between the center of the first sensor 54 and the center of the second sensor 55. In the present embodiment, b is 350 mm. Further, the spread of the lights L1 and L2 on the XY plane when reaching the detection surface 21 is about 18.925 °.

  The second positional deviation amount calculation unit 64 calculates a second positional deviation amount GX based on the position of the convex portion 22 specified from the data group P1 obtained by the first sensor 54. More specifically, the second positional deviation amount calculation unit 64 specifies the position of the convex portion 22 by extracting the boundary of the regions P11 and P12 and the boundary of the regions P12 and P13 from the data group P1. Then, the second positional deviation amount calculation unit 64 calculates the second positional deviation amount GX based on the positional relationship between the center of the convex portion 22 and the center of the data group P1. When the two coincide with each other, the second positional deviation amount GX is zero.

  In the example shown in FIG. 3, the first distance a1 and the second distance a2 do not match, and the center of the convex portion 22 matches the center of the data group P1. In this case, the transfer correction mechanism 52 performs only the correction regarding the first positional deviation amount Gθ.

  In another example shown in FIG. 6, the first distance a1 matches the second distance a2, and the center of the convex portion 22 matches the center of the data group P1. In this case, the transfer correction mechanism 52 does not perform correction.

  The first positional deviation amount Gθ may also be calculated by taking the difference between the third distance calculated from the data forming the area P11 of the data group P1 and the fourth distance calculated from the data forming the area P13. Can. However, with such a configuration, the calculation of the third distance and the fourth distance becomes inaccurate because the number of data on which the third distance and the fourth distance are calculated is small, and the first positional deviation amount The calculation of Gθ can also be inaccurate. The small difference between the third distance and the fourth distance also makes the first positional deviation amount Gθ inaccurate. Therefore, it is not preferable to calculate the first positional deviation amount Gθ using only the first sensor 54.

  As described above, according to the misregistration amount detection system according to the present embodiment, the mobile unit (unmanned conveyance vehicle) for the target (loading platform) has a simple configuration having only two sensors smaller than the conventional one. Various misalignment amounts can be detected with high accuracy.

Second Embodiment
The first distance a1 calculated using a part of the data forming the data group P1 obtained by the first sensor 54 uses all the data forming the data group P2 obtained by the second sensor 55. It is a little inferior in the point of linearity accuracy compared with the 2nd distance a2 calculated. In order to confirm this, the first distance a1 and the second distance a2 when changing the distance between the first loading platform 20 and the first unmanned transfer vehicle AGV1 while keeping the first positional deviation amount G.theta. From the calculation, it was found that there is a slight difference between the first distance a1 and the actual distance (second distance a2), as shown in FIG. Specifically, the first distance a1 is smaller than the actual distance in a region where the distance between the first loading platform 20 and the first unmanned transfer vehicle AGV1 is smaller than 200 mm, and the first loading platform 20 and the first unmanned transfer vehicle It has been found that in a region where the distance between the vehicle AGV1 and the vehicle is greater than 200 mm, the distance becomes larger than the actual distance.

  The positional deviation amount detection system according to the second embodiment of the present invention is characterized in that the positional deviation amount calculating portion 60B is provided instead of the positional deviation amount calculating portion 60A in order to compensate for the lack of accuracy of the first distance a1. It is different from the one embodiment. As shown in FIG. 7, the positional deviation calculation unit 60B includes a first distance calculation unit 61, a second distance calculation unit 62, a first positional deviation calculation unit 63, and a second positional deviation calculation unit 64. In addition to the above, the first distance correction unit 65 is further provided.

ここで、ａ１’は、補正後の第１距離である。 The first distance correction unit 65 corrects the first distance a1 calculated by the first distance calculation unit 61 according to a predetermined correction rule regarding the linearity accuracy of the first sensor 54. For example, the first distance correction unit 65 corrects the first distance a1 in accordance with a linear approximation formula expressed by the following equation, when the result as shown in FIG. 8 is obtained in a preliminary experiment.

Here, a1 'is the first distance after correction.

  Then, the first positional deviation amount calculation unit 63 calculates the first positional deviation amount based on the first distance a1 ′ corrected by the first distance correction unit 65 and the second distance a2 calculated by the second distance calculation unit 62. Calculate Gθ.

  According to the misregistration amount detection system according to the second embodiment, the first misregistration amount Gθ can be detected more accurately than in the first embodiment.

  The first and second embodiments of the displacement amount detection system according to the present invention have been described above, but the present invention is not limited to these configurations.

  For example, the field to which the present invention can be applied is not limited to unmanned transport systems. In other words, the present invention can be used to detect the position shift amount of any moving object at rest relative to any target.

  The detection surface 21 may have a recess instead of the protrusion 22.

  Further, the form of the rule for correcting the first distance a1 is not limited to the linear approximation, and may be, for example, a table form.

  Further, the positional deviation amount calculation units 60A and 60B may be provided outside the moving body.

  In addition, the light L1 emitted by the first sensor 54 may be applied to at least a part of the convex portion (or the concave portion) 22.

DESCRIPTION OF SYMBOLS 10 Unmanned conveyance system 11 Floor 12 Guidance line 20 1st load platform 21 to-be-detected surface 22 convex part 30 2nd load platform 40 3rd load platform 50 body part 51 Wheel 52 transfer correction mechanism 53 transfer device 54 1st sensor 55 2nd sensor 60A misregistration amount calculation unit (first embodiment)
60B Misalignment calculation unit (second embodiment)
61 first distance calculation unit 62 second distance calculation unit 63 first displacement amount calculation unit 64 second displacement amount calculation unit 65 first distance correction unit AGV1 first unmanned carrier AGV2 second unmanned carrier AGV3 third unmanned carrier Carrier AGV4 fourth unmanned carrier W luggage

Claims (4)

A positional deviation amount detection system for detecting the amount of stationary positional displacement of a movable body movable on the floor with respect to a target installed on the floor, comprising:
A detection surface provided on the target side and perpendicular to the floor;
A first sensor and a second sensor provided on the movable body side;
A displacement amount calculation unit that calculates the amount of displacement based on outputs of the first sensor and the second sensor;
Equipped with
The detected surface includes at least one concave / convex portion,
The first sensor and the second sensor are two-dimensional displacement sensors that emit light in a line parallel to the floor, detect reflected light corresponding to the light, and output the reflected light,
The first sensor is provided at a position such that the light of the first sensor is applied to at least a part of the concave / convex portion when the camera is at rest.
The second sensor is provided at a position away from the first sensor in a direction parallel to the floor such that the light of the second sensor does not fall on the concave / convex portions when the camera is at rest.
The positional deviation amount calculation unit calculates a distance between the first sensor and the detection surface, which is calculated from a portion of the output of the first sensor which is not the concave / convex portion, and the second sensor Calculating an amount of the positional deviation related to rotation around the normal line of the floor based on a distance between the second sensor calculated from the output of the sensor and the surface to be detected system. The positional deviation amount calculation unit further calculates an amount of positional deviation in a direction substantially parallel to both the floor and the detected surface based on the position of the concave / convex portion specified from the output of the first sensor. The misregistration amount detection system according to claim 1, wherein: The positional deviation amount calculation unit corrects the calculated distance between the first sensor and the surface to be detected according to a rule relating to the linearity accuracy of the first sensor, and the corrected distance, The amount of the positional deviation related to the rotation around the normal of the floor is calculated based on the calculated distance between the second sensor and the surface to be detected. Misalignment amount detection system described in. The moving body is an unmanned carrier,
The position shift amount detection system according to any one of claims 1 to 3, wherein the target is a loading platform on which a load to be transferred by the unmanned transfer vehicle is placed.

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