Position measurement device, position measurement method, and position measurement program

Abstract

To provide a position measurement device, a position measurement method, and a position measurement program, in which position detection accuracy can be improved when a sensor measures an object in a non-contact mode from above the object.SOLUTION: A position measurement device 1, a position measurement method, and a position measurement program use a controller 10 into which data are inputted from a sensor 50 for measuring an object in a non-contact mode from above the object. The sensor 50 has a primary scanning direction in which measurement points are aligned with a prescribed spacing when measuring the object and a sub-scanning direction in which measurement points are aligned with a wider spacing than the spacing in the primary scanning direction. The controller 10 acquires data on target measurement points within a detection target part from among measurement points spreading across the horizontal plane of a maker which has a reference point on a straight line suspended vertically from the sensor 50. The controller also calculates the attitude of the sensor 50 toward the reference point on the basis of the spacing distances.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a position measurement device, a position measurement method, and a position measurement program. [Background technology]

[0002] Patent Document 1 discloses a technology for installing a camera on the hoisting device of a yard bridge crane. According to this technology, the camera image is analyzed to detect the position of the container, and the crane is automatically controlled based on the relative positions of the hoisting device and the container. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-205891 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the technology described in Patent Document 1, a camera is attached to the hoisting device, which brings the camera closer to the container, which is the object to be measured. However, the hoisting device sways due to the influence of wind and other factors, causing the position and attitude of the camera to change from moment to moment. Depending on the position and attitude of the camera, it may not be possible to accurately detect the container's position using a fixed coordinate system used to indicate its position (during driving, automatic driving, etc.), making it difficult to constantly detect its position. This poses a problem of low position detection accuracy.

[0005] The present disclosure has been made in view of the above-mentioned problems, and has an object to provide a position measurement device, a position measurement method, and a position measurement program that can improve the position detection accuracy when measuring an object using a sensor that measures the object from above the object in a non-contact manner. [Means for solving the problem]

[0006] The position measurement device, position measurement method, and position measurement program according to the present disclosure use a controller that receives data from a sensor that measures an object from above the object without contact. The sensor has a main scanning direction in which measurement points are arranged at a predetermined density when measuring the object, and a sub-scanning direction in which the measurement points are arranged at a density lower than the density in the main scanning direction. The controller acquires, as target measurement points, measurement points related to the detection target portion of the marker, which has a reference point on a line extending vertically from the sensor and extends in a horizontal plane. Of the target measurement points, the controller groups the measurement points arranged in the main scanning direction to acquire at least a first group and a second group spaced apart in the sub-scanning direction. The controller calculates the orientation of the sensor relative to the reference point based on the length of the first group along the main scanning direction, the length of the second group along the main scanning direction, and the separation distance between the first and second groups along the sub-scanning direction.

[0007] The length of the detection target portion measured along the main scanning direction may vary in the sub-scanning direction.

[0008] The detection target portion may have a shape that is plane-symmetrical with respect to a plane that passes through the reference point and is perpendicular to the main scanning direction.

[0009] The controller may estimate that the reference point is on a line connecting the center point of the first group and the center point of the second group.

[0010] The controller may estimate that the reference point is a point on a line connecting the center point of the first group and the center point of the second group that divides the separation distance internally based on the length of the first group and the length of the second group.

[0011] The detection target portion may be made of a material that has retroreflective properties and has a reflectance higher than that of the surrounding area of ​​the detection target portion, or a reflectance lower than that of the surrounding area of ​​the detection target portion.

[0012] The controller may obtain the target measurement point based on the brightness of the measurement point.

[0013] The angle formed between the edge of the detection target portion and the main scanning direction may be in the range of 30 to 60 degrees.

[0014] The controller may calculate the position of the object in a coordinate system fixed to the ground and including a vertical coordinate axis.

[0015] The object may be lifted and transported by a gripper suspended from a trolley on which the sensor is disposed.

[0016] The gripping portion may move the object in the vertical direction.

[0017] The trolley may be supported by a girder that moves in a first direction and move in a second direction in which the girder extends that is different from the first direction. [Effects of the Invention]

[0018] According to the present disclosure, it is possible to improve the position detection accuracy when measuring an object using a sensor that measures the object from above the object in a non-contact manner. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a block diagram illustrating a configuration of a position measurement device according to an embodiment of the present disclosure. [Figure 2] 10 is a flowchart illustrating a processing procedure of the position measurement device according to the embodiment of the present disclosure. [Figure 3] FIG. 10 is a top view showing an example of the location of the sensor. [Figure 4] FIG. 10 is a cross-sectional view showing an example of the location of the sensor. [Figure 5] FIG. 10 is a schematic diagram showing measurement errors caused by the orientation of the sensor. [Figure 6] FIG. 10 is a diagram illustrating an example of the positional relationship between a sensor and a marker. [Figure 7A] 10A and 10B are diagrams illustrating a first example of the shape of a marker and the arrangement of measurement points. [Figure 7B] FIG. 10 is a diagram showing a second example of the shape of the marker and the arrangement of the measurement points. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, several exemplary embodiments will be described with reference to the drawings. Note that common parts in the drawings are given the same reference numerals, and duplicated explanations will be omitted.

[0021] [Configuration of position measurement device] Fig. 1 is a block diagram showing the configuration of a position measurement device according to an embodiment of the present disclosure. As shown in Fig. 1, the position measurement device 1 includes a controller 10. The controller 10 is connected to a sensor 50 so as to be able to communicate with the sensor 50, and data from the sensor 50 is input to the controller 10. In addition, the position measurement device 1 may include a database 20. The controller 10 is connected to the database 20 so as to be able to communicate with the database 20.

[0022] [Sensor example] The sensor 50 measures an object from above the object without contact. In particular, the sensor 50 has a main scanning direction DS1 and a sub-scanning direction DS2. Here, measurement points for measuring the object are arranged at a predetermined density in the main scanning direction DS1. Furthermore, measurement points are arranged at a lower density in the sub-scanning direction DS2 than in the main scanning direction DS1. Here, the "density" of the measurement is determined by the number of measurement points. For example, the density is the number of measurement points per unit length. The interval between measurement points in the sub-scanning direction DS2 is longer than the interval between measurement points in the main scanning direction DS1.

[0023] For example, the sensor 50 may be a sensor that measures the distance and direction to an object by emitting electromagnetic waves into the surroundings and detecting the position of a reflection point based on the reflected wave of the emitted electromagnetic wave. One example of such a sensor is a LIDAR (Laser Imaging Detection and Ranging). A LIDAR is a sensor that emits light (laser light) from an emission point within a predetermined range determined based on the position and attitude of the sensor 50, detects the position of a measurement point, which is a reflection point, based on the reflected wave, and generates measurement point data related to the measurement point.

[0024] The sensor 50 can be applied to the present disclosure as long as it can measure an object in a non-contact manner and measure the distance and direction to the object. The sensor 50 is not limited to the examples given here.

[0025] The sensor 50 may be disposed in a conveying device that grips and moves an object, or may be installed in a movable part or the like of the conveying device.

[0026] [Sensor placement location] Fig. 3 is a top view showing an example of a location where the sensor is arranged. Fig. 4 is a cross-sectional view showing an example of a location where the sensor is arranged. Figs. 3 and 4 show an example where the sensor 50 is installed on an overhead crane equipped with a girder GD and a trolley TR. The transport device on which the sensor 50 is installed is not limited to the example given here.

[0027] For example, the sensor 50 may be supported by a girder GD moving in a first direction AR1 and disposed on a trolley TR moving in a second direction AR2 in which the girder GD extends, different from the first direction AR1. The sensor 50 moves within a predetermined range due to the movement of the girder GD and the trolley TR. Here, the predetermined range is determined by the movement range of the girder GD and the movement range of the trolley TR.

[0028] As shown in Fig. 3, the girder GD moves on the rail RL in a first direction AR1. The trolley TR moves on the girder GD in a second direction AR2. Note that Fig. 3 shows the rail RL disposed between a pair of walls WL, but the walls WL may be omitted as long as the rail RL is fixed to the ground.

[0029] By moving the girder GD and the trolley TR to a predetermined position, the trolley TR is positioned above the object OBJ to be transported. Then, as shown in Fig. 4, the object OBJ may be gripped by a gripping part HD suspended from the trolley TR in a vertical direction AR3 (gravity direction) and transported within a predetermined range.

[0030] For example, the gripper HD may grip the object OBJ and move it in the vertical direction AR3. At that time, the cable between the gripper HD and the trolley TR may be wound up by a motor or the like (not shown), shortening the distance between the gripper HD and the trolley TR, causing the object OBJ to move upward. Conversely, the cable between the gripper HD and the trolley TR may be unwound from a wound state to an extended state, lengthening the distance between the gripper HD and the trolley TR, causing the object OBJ to move downward.

[0031] [Errors in position measurement by sensors] Next, a description will be given of errors that occur when the position of the object OBJ is measured by the sensor 50. Fig. 5 is a schematic diagram showing measurement errors caused by the attitude of the sensor.

[0032] When the sensor 50 moves, the posture of the sensor 50 may change before and after the movement. For example, when the sensor 50 is placed on the trolley TR as shown in Figures 3 and 4, the measurement direction of the sensor 50 may change due to distortion of the girder GD or distortion of the rail RL.

[0033] More specifically, the girder GD may have a curved shape such that the center portion is positioned higher than the ends. Therefore, the trolley TR does not always remain horizontal, and the measurement direction of the sensor 50 disposed on the trolley TR varies depending on the position of the trolley TR on the girder GD.

[0034] In addition, the rail RL may bend up and down. For example, the rail RL may bend due to ground subsidence after installation or errors during installation. Therefore, depending on the position of the girder GD on the rail RL, the girder GD may not be able to maintain horizontality, and the measurement direction of the sensor 50 arranged on the trolley TR may fluctuate due to the inclination of the girder GD.

[0035] 5, suppose that the sensor 50 should be facing in measurement direction PS1, but the measurement direction of the sensor 50 fluctuates, and as a result the sensor 50 faces in measurement direction PS2. Here, suppose that when the sensor 50 faces in measurement direction PS2, the distance from the sensor 50 to the object OBJ and the direction of the object OBJ as seen from the sensor 50 are acquired.

[0036] For example, the measurement range of the sensor 50 when the sensor 50 is facing the measurement direction PS1 is shown as region R1, and the measurement range of the sensor 50 when the sensor 50 is facing the measurement direction PS2 is shown as region R2.

[0037] If the position of the object VF in a coordinate system fixed to the ground is calculated based on the acquired distance and direction, assuming that the sensor 50 is facing the measurement direction PS1, the object VF, which should be at point P2, will end up being located at point P1. For example, the object VF will appear as the object OBJ.

[0038] As a result, it can be seen that an error DF occurs in the measurement by the sensor 50. The error DF becomes more significant as the distance between the sensor 50 and the object OBJ increases.

[0039] To avoid the occurrence of the error DF, it is necessary to acquire a correction angle AG that indicates the deviation of the measurement direction PS2 from the measurement direction PS1, taking into account cases where the attitude of the sensor 50 changes. Then, it is necessary to calculate the position of the object OBJ in a coordinate system fixed to the ground based on the acquired distance and direction by coordinate transformation corrected by the correction angle AG. For example, the attitude of the sensor 50 is acquired based on the case where the sensor 50 is facing the measurement direction PS1.

[0040] [Sensor and marker positional relationship] 6 is a diagram showing an example of the positional relationship between a sensor and a marker. Here, a marker MK is placed below the sensor 50. The marker MK has a reference point CP on a line extending from the sensor 50 in a vertical direction AR3, and extends within a horizontal plane. Here, the "horizontal plane" is a plane that is approximately perpendicular to the vertical direction AR3.

[0041] For example, the sensor 50 may be swung down, and the reference point CP of the marker MK may be aligned with the position of a weight WG attached to the tip of a string extending downward from the sensor 50 in the vertical direction AR3.

[0042] Then, the position of the reference point CP can be determined based on the arrangement of the measurement points on the marker MK measured by the sensor 50, and the attitude of the sensor 50 can be acquired based on the position of the reference point CP. In other words, with the straight line connecting the sensor 50 and the reference point CP as the measurement direction PS1, a correction angle AG indicating the deviation of the measurement direction PS2 from the measurement direction PS1 can be acquired.

[0043] The database 20 may store information indicating the attitude of the sensor 50. Alternatively, the database 20 may store the position of the object OBJ calculated by the controller 10.

[0044] The controller 10 is a general-purpose computer equipped with a CPU (Central Processing Unit), a memory, and an input / output unit. A computer program (position measurement program) for functioning as the position measurement device 1 is installed in the controller 10. By executing the computer program, the controller 10 functions as multiple information processing circuits (11, 13, 15, 17) equipped in the position measurement device 1.

[0045] In this disclosure, an example is shown in which multiple information processing circuits (11, 13, 15, 17) are realized by software. However, it is also possible to configure the information processing circuits (11, 13, 15, 17) by providing dedicated hardware for executing each of the information processes described below. Also, the multiple information processing circuits (11, 13, 15, 17) may be configured by individual hardware.

[0046] As shown in FIG. 1, the controller 10 includes a measurement point acquisition unit 11, a group acquisition unit 13, an attitude calculation unit 15, and a position calculation unit 17 as a plurality of information processing circuits (11, 13, 15, 17).

[0047] The measurement point acquisition unit 11 acquires, as target measurement points, measurement points relating to the detection target portion of the marker MK.

[0048] Fig. 7A is a diagram showing a first example of the shape of the marker and the arrangement of measurement points. Fig. 7B is a diagram showing a second example of the shape of the marker and the arrangement of measurement points. In Fig. 7A and Fig. 7B, the detection target portion of the marker MK is shown as an area filled with a horizontal stripe pattern.

[0049] 7A and 7B, the measurement points of the sensor 50 are indicated by white circles arranged closely in the main scanning direction DS1. The three rows of white circles are arranged at intervals in the sub-scanning direction DS2. The rows are shown spaced apart by a distance LW.

[0050] Here, the detection target portion of the marker MK may be configured so that the length of the detection target portion measured along the main scanning direction DS1 changes in the sub-scanning direction DS2.

[0051] 7A, the detection target portion is configured, for example, as a diamond, and the length of the detection target portion measured along the main scanning direction DS1 increases from 0 as it progresses in the sub-scanning direction DS2 (the direction from left to right in the figure) until it becomes the same length as the width of the marker MK. Thereafter, the length of the detection target portion decreases to 0 as it progresses in the sub-scanning direction DS2.

[0052] 7B, the length of the detection target portion measured along the main scanning direction DS1 decreases from the width of the marker MK as it progresses in the sub-scanning direction DS2, until it becomes 0. After that, the length of the detection target portion increases as it progresses in the sub-scanning direction DS2 until it becomes equal to the width of the marker MK.

[0053] Furthermore, the detection target portion of the marker MK may have a shape that is plane-symmetric with respect to a plane that passes through the reference point CP and is perpendicular to the main scanning direction DS1. For example, in Figures 7A and 7B, the marker MK has a shape that is line-symmetric with respect to a dashed line SY that passes through the reference point CP.

[0054] Alternatively, the angle between the edge of the detection target portion of the marker MK and the main scanning direction DS1 may be in the range of 30 to 60 degrees. This improves the accuracy of the orientation calculation by the orientation calculation unit 15, which will be described later. Here, the "edge" of the detection target portion means the boundary line between the detection target portion and the portion other than the detection target.

[0055] The detection target portion of the marker MK may be made of a material that has retroreflective properties and has a higher reflectivity than the surrounding area of ​​the detection target portion, or a lower reflectivity than the surrounding area of ​​the detection target portion. By having the detection target portion have a higher reflectivity than the surrounding area or a lower reflectivity than the surrounding area, the difference in reflectivity can be detected, making it easier to determine the boundary between the detection target portion and the non-detection target portion. As a result, it becomes easier to extract measurement points related to the detection target portion of the marker MK from the measurement points measured by the sensor 50.

[0056] For example, the measurement point acquisition unit 11 may extract, as target measurement points, measurement points having a reflectance equal to or greater than a predetermined threshold from among the measurement points measured by the sensor 50. Similarly, the measurement point acquisition unit 11 may extract, as target measurement points, measurement points having a reflectance less than a predetermined threshold from among the measurement points measured by the sensor 50. The measurement point acquisition unit 11 may acquire target measurement points based on the luminance of the measurement points.

[0057] Furthermore, the shape and material of the detection target portion of the marker MK are not limited to the examples given here.

[0058] The group acquisition unit 13 groups the measurement points arranged in the main scanning direction DS1 among the target measurement points, and acquires at least a first group GR1 and a second group GR2 spaced apart in the sub-scanning direction DS2.

[0059] For example, the sensor 50 has a main scanning direction DS1 in which the measurement points are arranged at a predetermined density, and a sub-scanning direction DS2 in which the measurement points are arranged at a lower density than the density in the main scanning direction DS1. Therefore, the group acquisition unit 13 can group the measurement points arranged in the main scanning direction DS1 by classifying measurement points that are arranged closer than a predetermined distance into the same group. Here, the "predetermined distance" is set to a value shorter than the distance LW.

[0060] 7A shows that the first group GR1 is made up of seven measurement points and the second group GR2 is made up of three measurement points. Also, in FIG. 7B, the first group GR1 is made up of three measurement points and the second group GR2 is made up of five measurement points. The number of measurement points making up each group varies depending on the density of the arrangement of the measurement points by the sensor 50 and the positional relationship between the sensor 50 and the marker MK.

[0061] The orientation calculation unit 15 calculates the orientation of the sensor 50 with respect to the reference point CP based on the length LA of the first group GR1 along the main scanning direction DS1, the length LB of the second group GR2 along the main scanning direction DS1, and the distance LW, where the distance LW is the separation distance between the first group GR1 and the second group GR2 along the sub-scanning direction DS2.

[0062] For example, the lengths LA and LB vary depending on the correction angle AG shown in Fig. 6. In other words, the correction angle AG can be calculated by determining the position of the reference point CP based on the lengths LA, LB, and the distance LW.

[0063] For example, the orientation calculation unit 15 may estimate that the reference point CP is located on a line connecting the center point CA of the first group GR1 and the center point CB of the second group GR2. As shown in Figures 7A and 7B, the reference point CP is located on a dashed line SY that passes through the center points CA and CB. The above estimation is possible because the detection target portion of the marker MK has a shape that is plane-symmetric with respect to a plane that passes through the reference point CP and is perpendicular to the main scanning direction DS1.

[0064] Alternatively, the orientation calculation unit 15 may estimate that a point that divides the distance LW is the reference point CP. The reference point CP divides the distance LW internally based on the length LA of the first group GR1 and the length LB of the second group GR2.

[0065] 7A and 7B, an example will be described in which the angle between the edge of the detection target portion of the marker MK and the main scanning direction DS1 is 45 degrees. In Fig. 7A, the distance between the first group GR1 and the reference point CP can be expressed as "LW / 2-(LA-LB) / 4".

[0066] 7B, the distance between the first group GR1 and the reference point CP can be expressed as "LW / 2+(LA-LB) / 4", or it can be calculated as "LW·LB / (LA+LB)".

[0067] The orientation calculation unit 15 may estimate the position of the reference point CP based on various calculation formulas set according to the shape of the detection target portion of the marker MK, and is not limited to the example given here.

[0068] The position calculation unit 17 acquires the direction of the object OBJ as seen from the sensor 50 and the distance between the sensor 50 and the object OBJ based on the data input from the sensor 50. Then, the position calculation unit 17 calculates the position of the object OBJ based on the acquired direction and distance.

[0069] More specifically, the position calculation unit 17 may calculate the position of the object OBJ in a coordinate system that includes a coordinate axis along the vertical direction AR3 and is fixed to the ground. In this case, the position calculation unit 17 performs correction based on the correction angle AG.

[0070] For example, the position calculation unit 17 may correct the direction of the object OBJ as seen from the sensor 50 by performing a rotational transformation based on a correction angle, and calculate the position of the object OBJ based on the corrected direction and the distance between the sensor 50 and the object OBJ. Alternatively, the position calculation unit 17 may calculate the position of the object OBJ based on the direction of the object OBJ as seen from the sensor 50 and the distance between the sensor 50 and the object OBJ, and correct the calculated position of the object OBJ by performing a rotational transformation based on a correction angle.

[0071] [Processing procedure for position measurement device] FIG. 2 is a flowchart showing a processing procedure of the position measurement device according to the embodiment of the present disclosure.

[0072] In step S101, the sensor 50 acquires a measurement point associated with the marker MK.

[0073] In step S103, the measurement point acquisition unit 11 acquires the measurement points relating to the detection target portions of the marker MK as target measurement points.

[0074] In step S105, the group acquisition unit 13 groups the target measurement points. In particular, the group acquisition unit 13 acquires at least a first group GR1 and a second group GR2 that are spaced apart in the sub-scanning direction DS2.

[0075] In step S107, the attitude calculation unit 15 calculates the attitude of the sensor 50.

[0076] In step S109, the position calculation unit 17 calculates the position of the object OBJ.

[0077] [Effects of the embodiment] As described above in detail, the position measurement device, position measurement method, and position measurement program according to the present disclosure use a controller that receives data from a sensor that measures an object from above the object in a non-contact manner. The sensor has a main scanning direction in which measurement points are arranged at a predetermined density when measuring the object, and a sub-scanning direction in which the measurement points are arranged at a density lower than that in the main scanning direction. The controller acquires, as target measurement points, measurement points associated with the detection target portion of the marker, which has a reference point on a line extending vertically from the sensor and extends in a horizontal plane. Of the target measurement points, the controller groups the measurement points arranged in the main scanning direction to acquire at least a first group and a second group spaced apart in the sub-scanning direction. The controller calculates the orientation of the sensor relative to the reference point based on the length of the first group along the main scanning direction, the length of the second group along the main scanning direction, and the separation distance between the first and second groups along the sub-scanning direction.

[0078] This improves the accuracy of position detection when measuring an object using a sensor that measures the object from above the object without contact. In particular, the orientation of the sensor relative to the vertical direction (the direction of gravity) can be determined with high accuracy. Even if the orientation of the sensor deviates from the vertical direction, it is possible to achieve both improved position detection accuracy and a shorter position detection time. For example, without using the method disclosed herein, when the orientation of the sensor deviates from the vertical direction, it may be necessary to lower the hoisting device from the sensor position and move it closer to the installation position to correct the detection position. However, according to the present disclosure, this work can be eliminated. As a result, the time required for position detection can be shortened.

[0079] The length of the detection target portion measured along the main scanning direction may vary in the sub-scanning direction, thereby determining the orientation of the sensor relative to the reference point of the marker.

[0080] The detection target portion may have a shape that is plane-symmetrical with respect to a plane that passes through the reference point and is perpendicular to the main scanning direction. This facilitates calculations when determining the position of the reference point of the marker. Furthermore, even if the marker is positioned at a slight angle from the plane perpendicular to the main scanning direction, the position of the reference point can be determined stably. Furthermore, the orientation of the sensor in the main scanning direction relative to the reference point of the marker can be determined.

[0081] The controller may estimate that the reference point is on a line connecting the center point of the first group and the center point of the second group, thereby easily determining the position of the reference point of the marker.

[0082] The controller may estimate a point on a line connecting the center point of the first group and the center point of the second group, which divides the separation distance internally based on the length of the first group and the length of the second group, as the reference point, thereby determining the orientation of the sensor in the sub-scanning direction relative to the reference point of the marker.

[0083] The detection target portion may be made of a material that has retroreflective properties and has a reflectance higher than that of the surrounding area of ​​the detection target portion, or a reflectance lower than that of the surrounding area of ​​the detection target portion.

[0084] The controller may acquire the target measurement point based on the brightness of the measurement point, thereby extracting the measurement point of the marker that corresponds to the portion to be detected and acquiring the target measurement point.

[0085] The angle between the edge of the detection target portion and the main scanning direction may be in the range of 30 to 60 degrees, which can suppress an increase in error when determining the orientation of the sensor relative to the reference point of the marker.

[0086] The controller may calculate the position of an object in a coordinate system fixed to the ground that includes a coordinate axis along the vertical direction. The position of the object in the coordinate system fixed to the ground can be determined with high accuracy. Even when approaching an object from a high position to transport and place it or to lower a hoist for lifting, a crane or other device moves the hoist or cargo up and down along a coordinate axis in the vertical direction (the direction of gravity). Therefore, by adjusting the horizontal plane position, the object can be lowered from a high position to the target location with high accuracy. Direct lowering from a high position to the target location improves work speed. Furthermore, objects can be placed closer together with higher density. As a result, the utilization efficiency of the space used to store objects can be improved.

[0087] The object may be lifted and transported by a gripper suspended from a trolley on which the sensor is mounted. This allows the objects to be densely packed in a plane perpendicular to the vertical direction, improving the utilization efficiency of the space for storing the objects to be transported. In addition, other objects can be stacked on top of the object.

[0088] The gripping portion may move the object in the vertical direction.

[0089] The trolley may be supported by a girder that moves in a first direction and move in a second direction in which the girder extends that is different from the first direction.

[0090] Each function described in the above embodiments may be implemented by one or more processing circuits, including programmed processors, electrical circuits, and even devices such as application specific integrated circuits (ASICs), or circuit components arranged to perform the described functions.

[0091] This disclosure enables highly accurate conversion between the sensor's coordinate system and a terrestrial coordinate system with coordinate axes aligned with the vertical direction (gravity direction). As a result, a workpiece can be efficiently grasped and positioned appropriately even from a high position, improving worker productivity. This can contribute to, for example, Goal 8 of the United Nations' Sustainable Development Goals (SDGs), "Promote inclusive and sustainable economic growth, full and productive employment and decent work for all."

[0092] Although several embodiments have been described, the embodiments can be modified or varied based on the above disclosure. All components of the above embodiments and all features described in the claims may be individually extracted and combined, unless they contradict each other. [Explanation of symbols]

[0093] 1 Position measurement device 10 Controller 11 Measurement point acquisition section 13 Group Acquisition Department 15 Posture calculation section 17 Position calculation section 20 databases 50 sensors AG correction angle AR1 1st direction AR2 2nd direction AR3 vertical direction CP reference point DS1 Main scanning direction DS2 Sub-scanning direction OBJ Object GD Guarda GR1 1st Group GR2 2nd Group HD grip part MK marker TR trolley

Claims

1. A position measurement device including a controller to which data is input from a sensor that measures an object from above the object in a non-contact manner, The sensor a main scanning direction in which measurement points are arranged at a predetermined density when measuring the object; a sub-scanning direction in which the measurement points are arranged at a density lower than the density in the main scanning direction; The controller A marker having a reference point on a line extending vertically from the sensor, the measurement point relating to a detection target portion of the marker extending in a horizontal plane is acquired as a target measurement point; grouping the measurement points arranged in the main scanning direction among the target measurement points to obtain at least a first group and a second group spaced apart in the sub-scanning direction; calculating an attitude of the sensor with respect to the reference point based on a length of the first group along the main scanning direction, a length of the second group along the main scanning direction, and a separation distance between the first group and the second group along the sub-scanning direction; Position measurement device.

2. 2. The position measurement device according to claim 1, wherein a length of the detection target portion measured along the main scanning direction varies in the sub-scanning direction.

3. The position measurement device according to claim 1 , wherein the detection target portion has a shape that is plane-symmetric with respect to a plane that passes through the reference point and is perpendicular to the main scanning direction.

4. The position measurement device according to claim 3 , wherein the controller estimates that the reference point is on a line connecting the center point of the first group and the center point of the second group.

5. 5. The position measurement device according to claim 4, wherein the controller estimates that the reference point is a point on a line connecting the center point of the first group and the center point of the second group that divides the separation distance internally based on the length of the first group and the length of the second group.

6. The detection target portion is Having retroreflectivity and a high reflectivity compared to the surrounding area of ​​the detection target portion, or A low reflectance compared to the surrounding area of ​​the detection target area The position measurement device according to claim 1 , which is made of a material having the following properties.

7. The position measurement device according to claim 6 , wherein the controller acquires the target measurement point based on the brightness of the measurement point.

8. 2. The position measurement device according to claim 1, wherein an angle formed between the edge of the detection target portion and the main scanning direction is in the range of 30 to 60 degrees.

9. 9. The position measurement device according to claim 1, wherein the controller calculates the position of the object in a coordinate system that includes a coordinate axis along a vertical direction and is fixed to the ground.

10. 9. The position measurement device according to claim 1, wherein the object is transported by being lifted by a gripper suspended from a trolley on which the sensor is disposed.

11. The position measurement device according to claim 10 , wherein the gripping unit moves the object in a vertical direction.

12. The position measurement device according to claim 10, wherein the trolley is supported by a girder that moves in a first direction and moves in a second direction in which the girder extends, which is different from the first direction.

13. A position measurement method for controlling a controller to which data from a sensor that measures an object from above the object in a non-contact manner is input, comprising: The sensor a main scanning direction in which measurement points are arranged at a predetermined density when measuring the object; a sub-scanning direction in which the measurement points are arranged at a density lower than the density in the main scanning direction; The controller A marker having a reference point on a line extending vertically from the sensor, the measurement point relating to a detection target portion of the marker extending in a horizontal plane is acquired as a target measurement point; grouping the measurement points arranged in the main scanning direction among the target measurement points to obtain at least a first group and a second group spaced apart in the sub-scanning direction; calculating an attitude of the sensor with respect to the reference point based on a length of the first group along the main scanning direction, a length of the second group along the main scanning direction, and a separation distance between the first group and the second group along the sub-scanning direction; Position measurement method.

14. A position measurement program to be executed in a controller to which data from a sensor that measures an object from above the object in a non-contact manner is input, The sensor a main scanning direction in which measurement points are arranged at a predetermined density when measuring the object; a sub-scanning direction in which the measurement points are arranged at a density lower than the density in the main scanning direction; The controller a step of acquiring, as a target measurement point, a measurement point of a marker having a reference point on a line extending vertically from the sensor, the measurement point relating to a detection target portion of the marker extending in a horizontal plane; grouping the measurement points arranged in the main scanning direction among the target measurement points to obtain at least a first group and a second group spaced apart in the sub-scanning direction; calculating an attitude of the sensor with respect to the reference point based on a length of the first group along the main scanning direction, a length of the second group along the main scanning direction, and a separation distance between the first group and the second group along the sub-scanning direction; A position measurement program comprising:

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