阅读说明：本技术 移动体的位置偏移量检测系统 (System for detecting amount of positional deviation of moving body ) 是由 山崎智久 于 2019-02-22 设计创作，主要内容包括：本发明提供一种位置偏移量检测系统,能够以传感器的数量较少的简单结构实现,并且能够高精度地检测移动体相对于目标的各种位置偏移量。本发明的位置偏移量检测系统具备：被检测面,其设置在目标一侧；传感器,其设置在移动体一侧；和位置偏移量计算部,其基于传感器的输出计算位置偏移量。传感器设置于在静止时光施加于凸部的位置,传感器设置于在静止时光不施加于凸部的位置。位置偏移量计算部基于根据传感器的输出中的与并非凸部的部分相关的输出计算出的距离、和根据传感器的输出计算出的距离,计算与绕Z轴的旋转相关的位置偏移量。(The invention provides a position deviation amount detection system which can be realized by a simple structure with a small number of sensors and can detect various position deviation amounts of a moving body relative to a target with high precision. The position deviation amount detection system of the present invention includes: a detected surface arranged on one side of the target; a sensor provided on a side of the moving body; and a positional deviation amount calculation section that calculates a positional deviation amount based on an output of the sensor. The sensor is provided at a position where light is applied to the convex portion when the sensor is at rest, and the sensor is provided at a position where light is not applied to the convex portion when the sensor is at rest. The positional deviation amount calculation unit calculates a positional deviation amount relating to rotation about the Z axis based on a distance calculated from an output of a portion of the sensor that is not the convex portion and a distance calculated from the output of the sensor.)

1. A positional displacement amount detection system detects a positional displacement amount at rest of a mobile body movable on a floor with respect to an object provided on the floor,

the positional displacement amount detection system is characterized by comprising:

a detected surface which is perpendicular to the floor and is arranged on one side of the target;

a first sensor and a second sensor provided on the moving body side; and

a positional deviation amount calculation section that calculates the positional deviation amount based on outputs of the first sensor and the second sensor,

the surface to be detected contains at least one concave/convex part,

the first sensor and the second sensor are two-dimensional displacement sensors that irradiate light in a linear form parallel to the floor, detect reflected light corresponding to the light, and output an output related to the reflected light,

the first sensor is provided at a position where the light of the first sensor is applied to at least a part of the concave/convex portion when the moving body is stationary,

the second sensor is provided at a position where the light of the second sensor is not applied to the concave/convex portion and is separated from the first sensor in a direction parallel to the floor when the mobile body is stationary,

the positional deviation amount calculation unit calculates the positional deviation amount with respect to rotation around the normal of the floor based on a distance between the first sensor and the surface to be detected calculated from an output of the first sensor with respect to a portion other than the concave/convex portion and a distance between the second sensor and the surface to be detected calculated from an output of the second sensor.

2. The positional offset detection system according to claim 1,

the positional deviation amount calculation unit further calculates the positional deviation amount in a direction substantially parallel to both the floor panel and the detected surface based on the position of the concave/convex portion determined from the output of the first sensor.

3. The positional offset detection system according to claim 1 or 2,

the positional offset amount calculation unit corrects the calculated distance between the first sensor and the surface to be detected according to a rule relating to linear accuracy of the first sensor, which is set in advance, and calculates the positional offset amount relating to rotation around the normal line of the floor based on the corrected distance and the calculated distance between the second sensor and the surface to be detected.

4. The positional offset detection system according to claim 1,

the moving body is an automated guided vehicle,

the target is a cargo bed on which goods for the automated guided vehicle to carry are placed.

Technical Field

The present invention relates to a positional displacement amount detection system that detects a positional displacement amount of a moving body movable on a floor when the moving body is stationary with respect to an object provided on the floor.

Background

Conventionally, in an unmanned factory or the like, a process of (1) moving an unmanned transport vehicle as a moving body to the vicinity of a target cargo bed and standing still is automatically repeated; (2) the unmanned transport vehicle collects goods from the cargo carrying platform; (3) the unmanned transport vehicle for collecting goods moves to the vicinity of other goods loading platforms and is static; and (4) the unmanned transport vehicle hands over the goods to the cargo carrying platform. In such a so-called unmanned transport system, in order to reliably and accurately carry out the pickup and transfer of the cargo, it is necessary to accurately align the movable body with respect to the target.

As a conventional technique related to positioning with respect to a target, although not an unmanned conveyance system, there is a system described in patent document 1, for example. In this system, the parallelism of the forks with respect to the target pallet is detected by the two ultrasonic type displacement sensors on the left and right, and the lateral displacement of the forks with respect to the pallet is detected by the two optical type position sensors on the left and right.

Patent document 1: japanese laid-open patent publication No. 10-291797

However, the above-described conventional system has various problems that (1) four sensors must be prepared in order to detect two kinds of positional deviations; (2) the accuracy of the amount of positional displacement relating to rotation detected by the ultrasonic displacement sensor is certainly not high; and (3) although the presence or absence of the lateral position deviation can be detected, the amount of the position deviation cannot be detected.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a positional displacement amount detection system which can be realized with a simple configuration with a small number of sensors and can detect various positional displacement amounts of a moving body with respect to a target with high accuracy.

In order to solve the above problem, a positional deviation amount detection system according to the present invention is a positional deviation amount detection system for detecting a positional deviation amount of a moving body movable on a floor when the moving body is stationary with respect to an object provided on the floor, the positional deviation amount detection system including: the detected surface is vertical to the floor and is arranged on one side of the target; a first sensor and a second sensor provided on the moving body side; and a positional deviation amount calculation unit that calculates a positional deviation amount based on outputs of a first sensor and a second sensor, the detected surface including at least one concave/convex portion, the first sensor and the second sensor being two-dimensional displacement sensors that irradiate light in a linear form parallel to a floor, detect reflected light corresponding to the light, and perform output related to the reflected light, the first sensor being provided at a position where the light of the first sensor is applied to at least a part of the concave/convex portion when the mobile body is stationary, the second sensor being provided at a position where the light of the second sensor is not applied to the concave/convex portion and is separated from the first sensor in a direction parallel to the floor when the mobile body is stationary, the positional deviation amount calculation unit being based on a distance between the first sensor and the detected surface calculated based on the output related to the part other than the concave/convex portion among the outputs of the first sensor, And calculating a positional displacement amount associated with rotation around a normal line of the floor from a distance between the second sensor and the detected surface calculated from an output of the second sensor.

Preferably, the positional deviation amount calculation unit of the positional deviation amount detection system further calculates the positional deviation amount in a direction substantially parallel to both the floor and the detected surface, based on the position of the concave/convex portion determined based on the output of the first sensor.

Preferably, the positional deviation amount calculation unit of the positional deviation amount detection system corrects the calculated distance between the first sensor and the surface to be detected according to a rule relating to linearity accuracy of the first sensor set in advance, and calculates the positional deviation amount relating to rotation around the normal line of the floor based on the corrected distance and the calculated distance between the second sensor and the surface to be detected.

The moving body of the positional deviation amount detection system is, for example, an automated guided vehicle, and the target is, for example, a loading table on which a load for transporting the automated guided vehicle is placed.

According to the present invention, it is possible to provide a positional displacement amount detection system which can be realized with a simple configuration with a small number of sensors and can detect various positional displacement amounts of a moving body with respect to a target with high accuracy.

Drawings

Fig. 1 is a schematic plan view showing an entire unmanned conveyance system incorporating a positional displacement amount detection system according to a first embodiment of the present invention.

Fig. 2 is a plan view and a side view showing a part of an unmanned conveyance system in which the positional deviation amount detection system of the first embodiment is incorporated.

Fig. 3 is a diagram showing a positional displacement amount detection system according to the first embodiment.

Fig. 4 is a diagram showing data sets output from the first sensor and the second sensor shown in fig. 3.

Fig. 5 is a diagram for explaining an operation of the first position displacement amount calculation unit shown in fig. 3.

Fig. 6 is a diagram showing the positional displacement amount detection system of the first embodiment (however, different from fig. 3 in the manner of positional displacement).

Fig. 7 is a diagram showing a positional displacement amount detection system according to a second embodiment of the present invention.

Fig. 8 is a diagram for explaining an operation of the first distance correcting unit shown in fig. 7.

Description of reference numerals:

10 … unmanned handling system; 11 … floor board; 12 … guide wire; 20 … a first cargo bed; 21 … detected surface; 22 … protrusions; 30 … second cargo bed; 40 … third cargo bed; 50 … a body portion; 51 … wheels; 52 … transfer correction mechanism; 53 … transfer device; 54 … a first sensor; 55 … second sensor; a 60a … positional displacement amount calculation section (first embodiment); a 60B … positional displacement amount calculation section (second embodiment); 61 … a first distance calculating unit; 62 … a second distance calculating section; 63 … a first position displacement amount calculation unit; 64 … a second position displacement amount calculating section; 65 … first distance correction part; AGV1 … a first automated guided vehicle; AGV2 … second automated guided vehicle; AGV3 … third automated guided vehicle; AGV4 … fourth automated guided vehicle; w … goods.

Detailed Description

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

[ first embodiment ]

Fig. 1 shows an unmanned conveyance system 10 incorporating a positional displacement amount detection system according to a first embodiment of the present invention. As shown in the drawing, the automated guided vehicle system 10 includes a substantially annular guide line 12 laid on a floor 11, three loading platforms 20, 30, and 40 provided on the floor 11, and four automated guided vehicles AGV1, AGV2, AGV3, and AGV4 that move on the floor 11 along the guide line 12. In the present embodiment, each of the automated guided vehicles AGVs 1, AGVs 2, AGVs 3, AGVs 4 carries the load W picked up from the first load board 20 or the second load board 30 to the third load board 40. In the present embodiment, the loading platforms 20, 30, and 40 correspond to the "targets" of the present invention, and the automated guided vehicles AGV1, AGV2, AGV3, and AGV4 correspond to the "moving bodies" of the present invention.

Fig. 2 shows the first loading dock 20 and a first automated guided vehicle AGV1 stationary near the first loading dock 20 for receiving a load W. As shown in the figure, the first cargo bed 20 includes a detection surface 21 perpendicular to the floor 11, and the detection surface 21 includes a convex portion 22. The first automated guided vehicle AGV1 includes a main body 50 having a plurality of wheels 51 at a lower portion thereof, a transfer device 53 for receiving and transferring the load W, a transfer correction mechanism 52 provided between the main body 50 and the transfer device 53, a first sensor 54 and a second sensor 55 facing the first loading platform 20, and a positional deviation amount calculation unit 60A accommodated in the main body 50. The positional deviation amount detection system of the present embodiment is constituted by the detected surface 21, the first sensor 54, the second sensor 55, and the positional deviation amount calculation section 60A among them.

Hereinafter, 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. In addition, the guide line 12 extends in the X direction in the vicinity of the first loading dock 20, and the first sensor 54 and the second sensor 55 are separated only in the X direction when the positional offset amount of the first automated guided vehicle AGV1 with respect to the first loading dock 20 is zero.

The first sensor 54 and the second sensor 55 are optical reflection type two-dimensional displacement sensors that irradiate linear light beams L1, L2 parallel to the floor 11(XY plane), detect reflected light beams corresponding to the irradiated light beams L1, L2, and output data on the reflected light beams to the positional deviation amount calculation unit 60A. As shown in fig. 2 (a), the first sensor 54 is provided at a position where the light L1 is applied to the convex portion 22 of the detection target surface 21 when the first automated guided vehicle AGV1 is stationary, more specifically, at a position where the light L1 crosses the convex portion 22. On the other hand, the second sensor 55 is provided at a position where the light L2 is not applied to the convex portion 22 when the first automated guided vehicle AGV1 is stationary.

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 based on the data output from the first sensor 54 and the second sensor 55, and outputs the detected positional deviation amount to the transfer correction mechanism 52. The transfer correction means 52 corrects the position (relative position with respect to the main body 50) and the operation of the transfer device 53, which is constituted by an arm or the like that extends out to the load table 20 and transfers the load W, based on the positional deviation amount. This eliminates the positional deviation of the first automated guided vehicle AGV1 with respect to the first cargo bed 20, and allows the cargo W to be reliably and accurately picked up and delivered.

The positional deviation amount calculation unit 60A calculates a positional deviation amount (hereinafter referred to as "first positional deviation amount G θ") relating to rotation about a normal line (Z axis) of the floor panel 11 and a positional deviation amount (hereinafter referred to as "second positional deviation amount GX") in a direction (X direction) substantially parallel to both the floor panel 11 and the detected surface 21, which will be described in detail later. The first position displacement amount G θ and the second position displacement amount GX correspond to the parallelism and the lateral displacement in the above-described prior art, respectively.

The procedure until the sorting position offset amount is eliminated is as follows.

(1) The first automated guided vehicle AGV1 is stationary near the first load bed 20.

(2) The first sensor 54 and the second sensor 55 start irradiation of lights L1, L2.

(3) 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 bay 20 based on the data output from the first sensor 54 and the second sensor 55.

(4) The transfer correction mechanism 52 corrects the position and operation of the transfer device 53 based on the detected amount of positional deviation.

Next, the operation of the positional deviation amount calculation unit 60A will be described in further detail with reference to fig. 3 to 6.

As shown in fig. 3 and the like, the positional deviation amount calculation section 60A has a first distance calculation section 61, a second distance calculation section 62, a first positional deviation amount calculation section 63, and a second positional deviation amount calculation section 64. The first distance calculating unit 61 is connected to the first sensor 54 and the first displacement amount calculating unit 63, and the second distance calculating unit 62 is connected to the second sensor 55 and the first displacement amount calculating unit 63. The second position displacement amount calculation unit 64 is connected to the first sensor 54. Although not shown, the first position displacement amount calculation unit 63 and the second position displacement amount calculation unit 64 are also connected to the transfer correction mechanism 52.

The first distance calculation unit 61 calculates the distance between the first sensor 54 and the detection surface 21 (hereinafter referred to as "first distance a 1") using data included in the regions P11 and P13 not applied to the convex portion 22, among the n data D11, D12, ·, D1n constituting the data group P1 (see fig. 4 a) obtained by the first sensor 54. More specifically, the first distance calculator 61 calculates the first distance a1 by averaging the distances between the detection surface 21 and the first sensor 54 indicated by the data included in the regions P11 and P13. In this case, the first distance calculating unit 61 may calculate the distance using not all the data included in the regions P11 and P13 but a part of the data.

The second distance calculator 62 calculates the distance between the second sensor 55 and the detection surface 21 (hereinafter referred to as "second distance a 2") using n data D21, D22, ·, D2n constituting the data group P2 (see fig. 4B) obtained by the second sensor 55. More specifically, the second distance calculator 62 calculates the second distance a2 by averaging the distances between the second sensor 55 and the detection target surface 21, which are indicated by the data included in the data group P2. In this case, the second distance calculating unit 62 preferably performs calculation using all the data included in the data group P2.

In this embodiment, n is 631. Fig. 4 is a schematic diagram, and it should be noted that the number of n is not accurately represented.

The first position displacement amount calculation section 63 calculates a first position displacement amount G θ based on the calculated first distance a1 and second distance a 2. More specifically, the first position displacement amount calculation unit 63 calculates the first position displacement amount G θ using the following expression derived from fig. 5.

[ formula 1 ]

Here, b is a distance between the center of the first sensor 54 and the center of the second sensor 55. In this embodiment, b is 350 mm. After reaching the detection surface 21, the light beams L1 and L2 have a spread of about 18.925 ° in the XY plane, respectively.

The second positional displacement amount calculation section 64 calculates the second positional displacement amount GX based on the position of the convex portion 22 determined from the data group P1 obtained by the first sensor 54. More specifically, the second position displacement amount calculation unit 64 extracts the boundary between the regions P11 and P12 and the boundary between the regions P12 and P13 from the data group P1, and thereby determines the position of the convex portion 22. The second displacement amount calculation unit 64 calculates the second displacement amount GX based on the positional relationship between the center of the convex portion 22 and the center of the data group P1. When both of them coincide with each other, the second position offset amount GX is zero.

In one example shown in fig. 3, first distance a1 does not coincide with second distance a2, and the center of lobe 22 coincides with the center of data set P1. At this time, the transfer correction mechanism 52 performs correction only with respect to the first position displacement amount G θ.

In another example shown in fig. 6, the first distance a1 coincides with the second distance a2, and the center of the convex portion 22 coincides with the center of the data group P1. At this time, the transfer correction mechanism 52 does not perform correction.

Further, the first position displacement amount G θ can also be calculated by obtaining a difference between a third distance, which is a distance calculated from data of the constituent region P11 of the data group P1, and a fourth distance, which is a distance calculated from data of the constituent region P13. However, with such a configuration, the number of data on which the third distance and the fourth distance are calculated is small, and therefore the third distance and the fourth distance may not be accurately calculated, and the first position displacement amount G θ may not be accurately calculated. The smaller difference between the third distance and the fourth distance also makes the first position displacement amount G θ inaccurate. Therefore, it is not preferable to calculate the first position displacement amount G θ using only the first sensor 54.

As described above, the positional deviation amount detection system according to the present embodiment can be realized with a simple configuration including only two sensors less than those of the conventional art, and can detect various positional deviation amounts of a moving body (automated guided vehicle) with respect to a target (cargo bed) with high accuracy.

[ second embodiment ]

The linearity accuracy of the first distance a1 calculated using a part of the data of the configuration data group P1 obtained by the first sensor 54 is slightly inferior to the second distance a2 calculated using the entire data of the configuration data group P2 obtained by the second sensor 55. In order to confirm this point, if the first distance a1 and the second distance a2 are calculated after the distance between the first loading platform 20 and the first automated guided vehicle AGV1 is changed while keeping the first position deviation amount G θ zero, as shown in fig. 8, there is a slight difference between the first distance a1 and the actual distance (the second distance a 2). Specifically, it is found that the first distance a1 is smaller than the actual distance in the area where the distance between the first load platform 20 and the first automated guided vehicle AGV1 is less than 200mm, and the first distance a1 is greater than the actual distance in the area where the distance between the first load platform 20 and the first automated guided vehicle AGV1 is greater than 200 mm.

In order to compensate for the lack of accuracy of the first distance a1, the positional displacement amount detection system of the second embodiment of the present invention is provided with a positional displacement amount calculation unit 60B instead of the positional displacement amount calculation unit 60A, and the second embodiment differs from the first embodiment in this point. As shown in fig. 7, the positional deviation amount calculation unit 60B includes a first distance correction unit 65 in addition to the first distance calculation unit 61, the second distance calculation unit 62, the first positional deviation amount calculation unit 63, and the second positional deviation amount calculation unit 64.

The first distance correcting unit 65 corrects the first distance a1 calculated by the first distance calculating unit 61 according to a preset correction rule relating to the linearity accuracy of the first sensor 54. For example, when the result shown in fig. 8 is obtained by a previous experiment, the first distance correction unit 65 corrects the first distance a1 according to a linear approximation formula represented by the following formula.

[ formula 2 ]

Here, a 1' is the corrected first distance.

Then, the first position displacement amount calculation unit 63 calculates the first position displacement amount G θ based on the first distance a 1' corrected by the first distance correction unit 65 and the second distance a2 calculated by the second distance calculation unit 62.

According to the positional deviation amount detection system of the second embodiment, the first positional deviation amount G θ can be detected with higher accuracy than that of the first embodiment.

The first and second embodiments of the positional 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 the unmanned conveyance system. In other words, the present invention can be used to detect the amount of positional displacement of an arbitrary moving body at rest with respect to an arbitrary target.

The detection surface 21 may have a concave portion instead of the convex portion 22.

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

The position deviation amount calculation units 60A and 60B may be provided outside the moving body.

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