WO2024214297A1 - Topography measurement device, topography measurement system, work machine, topography measurement method, reference point setting registration method, and program - Google Patents

Abstract

This topography measurement device, which is mounted on a movable body and measures the shape of the ground in a construction site, comprises: a reference point registration unit in which position information pertaining to at least one or more reference points in the construction site is registered; a position detection unit that detects the position of a point cloud in a global coordinate system on the basis of point cloud data acquired from a distance measurement device for measuring the distance to the ground; a display unit that displays, on a screen, a distance measurement image of an area scanned by the distance measurement device; a reference point detection unit that detects a reference point present in the area from among the at least one or more reference points; and a correction unit that extracts, from the point cloud present in the area, a scan point located at the shortest horizontal distance from the reference point detected by the reference point detection unit and also within a prescribed distance from said reference point, and that corrects the coordinates of the point cloud in the height direction on the basis of a correction value calculated from a coordinate error in the height direction with reference to the reference point.

Description

Topography measuring device, topography measuring system, work machine, topography measuring method, reference point setting and registration method and program

The present invention relates to a topography measurement device, a topography measurement system, a work machine, a topography measurement method, a reference point setting and registration method, and a program.

By installing a terrain measurement device equipped with LiDAR (Light Detection And Ranging) and an IMU (Inertial Measurement Unit) in the driver's cab of a hydraulic excavator, the terrain in front of the hydraulic excavator can be detected by LiDAR, and by providing a reference height, any unevenness relative to the reference height can be displayed in color on the screen. The operator can look at the color-coded unevenness on the screen and operate the hydraulic excavator's bucket or blade to excavate the ground until the colors on the screen become the same, i.e., the unevenness disappears.

The terrain measurement device detects reference points from markers and performs terrain measurements based on the reference points. The hydraulic excavator moves away from the reference point by turning and traveling, but the terrain measurement device estimates the position and tilt of the device (camera) from the built-in gyro sensor, acceleration sensor, and changes in feature points in the image (Visual Inertial Odometry, or SLAM: Simultaneous Localization and Mapping), making it possible to continue to determine accurate terrain coordinates even when it moves away from the reference point. However, it is known that if the travel distance is large, estimation errors accumulate and the coordinate deviation becomes large. As a countermeasure, a method is available in which a marker whose positional relationship with the reference point is known is installed at a position away from the reference point, and the position error is corrected by recognizing the marker.

For example, Patent Document 1 discloses a method of photographing markers installed in locations where height information is required with a camera mounted on construction machinery while the machinery is traveling, acquiring the position coordinates of the markers in the image and the position coordinates of the camera, acquiring the relative positional relationship between multiple markers using VisualSLAM technology to create Triangulated Irregular Network (TIN) data, and identifying planes to create 3D design data. Patent Document 2 discloses a method of linking the position coordinates of markers read from markers placed along a travel path with the position coordinates of markers detected by a stereo camera to create virtual marker information for the travel path, and using the virtual marker information as corrected travel information to drive a moving vehicle autonomously.

JP 2023-11454 A JP 2022-34519 A

However, this method requires the preparation of equipment called markers, and the additional process of recognizing the markers puts a heavy load on the CPU (Central Processing Unit), resulting in delays in the process of detecting the terrain in real time.

The present invention was made in consideration of the above-mentioned circumstances, and aims to reduce the load on the CPU when detecting terrain in real time by eliminating the need to provide markers and perform the process of recognizing the markers, thereby speeding up the process of detecting terrain in real time.

In order to achieve the above object, a topographical measuring device according to the present invention comprises:
A topographical measurement device that is mounted on a moving body and measures the shape of the ground at a construction site,
a reference point registration unit in which position information of at least one reference point within the construction site is registered;
a position detection unit that detects a position of the point cloud in a global coordinate system based on point cloud data acquired from a distance measurement device that measures a distance to the ground;
a display unit that displays a distance measurement image of an area scanned by the distance measurement device;
a reference point detection unit that detects a reference point that exists within the area among the at least one reference point;
a correction unit that extracts, from the point cloud present within the area, a scanning point that has a minimum horizontal distance from the reference point detected by the reference point detection unit and is within a predetermined distance, and corrects the height coordinate of the point cloud based on a correction value calculated from a height coordinate error from the reference point.

According to the present invention, by correcting the height coordinate position of the point cloud according to the height coordinate position of the reference point, it is possible to reduce the load on the CPU and speed up the process of detecting the terrain in real time by eliminating the need to provide markers and to process the markers.

1 is a diagram showing a configuration of a work machine according to a first embodiment of the present invention. 1 is a block diagram of a topographical measurement system according to a first embodiment of the present invention. FIG. FIG. 2 is a block diagram of a controller according to the first embodiment of the present invention. FIG. 13 is a diagram showing a display image in which a distance measurement image is superimposed on a captured image. FIG. 13 is a diagram showing how a reference point is set at a construction site and measurements are taken. FIG. 13 is a diagram showing a state in which a reference point set at a construction site is registered. 5 is a flowchart showing a reference point registration process according to the first embodiment of the present invention. 1 is a diagram showing point cloud positions and reference point positions detected by a distance measuring device during topography measurement; 5 is a flowchart showing a Z position correction process according to the first embodiment of the present invention. FIG. 13 shows the movement of a work machine when setting and registering a reference point in a second embodiment of the present invention, with the first reference point k1 entering the screen of the display unit and the work machine stopped. FIG. 2 is a diagram showing a state in which the rotating body of the work machine has been rotated rearward. FIG. 13 is a diagram showing a state in which the rotating bed has been returned to its original position and the work machine has been moved rearward. FIG. 2 is a diagram showing a state in which the rotating body has rotated rearward. 10 is a flowchart showing a reference point setting and registration process according to a second embodiment of the present invention.

(First embodiment)
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A topographical measuring device according to a first embodiment of the present invention will now be described in detail with reference to the drawings.

The configuration of a work machine according to a first embodiment of the present invention is shown in FIG. 1. The work machine is a mobile body that moves around a construction site to perform work, and here, as an example of a work machine, a hydraulic excavator equipped with a work implement that operates hydraulically is shown. The work machine 1 comprises a vehicle body that comprises a running body 2 and a rotating body 3 supported by the running body 2, and a work implement 4 supported by the rotating body 3.

The running body 2 has tracks on both the left and right sides, and moves by rotating the tracks. Note that the running body 2 may also be configured to move by having tires instead of tracks. The rotating body 3 is supported on the running body 2 so that it can rotate around a rotation axis.

The work machine 4 includes a boom 41 connected to the rotating body 3 so as to be rotatable up and down, an arm 42 connected to the boom 41 so as to be rotatable up and down, and a bucket 43 connected to the arm 42 so as to be rotatable up and down.

The base end of the boom 41 is attached to the rotating body 3 via a boom pin 44, and the boom 41 rotates around the boom pin 44 as the boom cylinder 45 extends and retracts. The base end of the arm 42 is attached to the tip of the boom 41 via an arm pin 46, and the arm 42 rotates around the arm pin 46 as the arm cylinder 47 extends and retracts. The base end of the bucket 43 is attached to the tip of the arm 42 via a bucket pin 48, and the bucket 43 rotates around the bucket pin 48 as the bucket cylinder 49 extends and retracts.

The boom cylinder 45 is a hydraulic cylinder that can be extended and retracted by hydraulic pressure. The base end of the boom cylinder 45 is connected to the rotating body 3, and the tip end is connected to the boom 41. The arm cylinder 47 is a hydraulic cylinder that can be extended and retracted by hydraulic pressure. The base end of the arm cylinder 47 is connected to the boom 41, and the tip end is connected to the arm 42. The bucket cylinder 49 is a hydraulic cylinder that can be extended and retracted by hydraulic pressure. The base end of the bucket cylinder 49 is connected to the arm 42, and the tip end is connected to the bucket 43. The bucket 43 is equipped with a cutting edge at the tip for excavating soil and sand, and a storage section for storing the excavated soil.

In addition, a blade 50 is disposed in front of the traveling body 2 as a working machine 4. The blade 50 rotates up and down as shown by the arrow by the extension and contraction of a lift cylinder (not shown).

A cab 31 where the operator drives is provided on top of the rotating body 3. The cab 31 is equipped with an operating device 32 for operating the work machine 4 and a topography measuring device 5.

The operating device 32 is equipped with an operating lever, and in addition to operating the travelling body 2, the operating lever is used to operate the boom 41, the arm 42, the bucket 43, the blade 50, and to rotate the rotating body 3. Depending on the operation, the boom cylinder 45, the arm cylinder 47, the bucket cylinder 49, and the lift cylinder are extended or retracted, and the work machine 4 is driven.

In addition, a distance measuring device 6 that detects the distance to the work machine 4 and the work target, and an imaging device 7 that captures images of the work machine 4 and the work target are provided inside the cab 31, and the imaging device 7 is attached integrally to the distance measuring device 6.

The distance measuring device 6 is arranged so that its detection surface faces diagonally downward so that it can detect the direction of the ground in front of the cab 31, which is the direction in which the work machine 4 of the rotating body 3 is connected. Similarly to the distance measuring device 6, the imaging device 7 is arranged so that its imaging surface faces diagonally downward so that it can detect the direction of the ground in front of the cab 31, which is the direction in which the work machine 4 of the rotating body 3 is connected, and captures images in the same direction as the distance measuring device 6.

The distance measuring device 6 is, for example, a LiDAR, and is a sensor that irradiates a pulsed laser light while scanning sequentially in multiple measurement directions, and measures the distance and direction to a measurement object within a certain measurement range based on the time it takes for the reflected scattered light to return and the irradiation direction. The distance measuring device 6 outputs point cloud data that indicates the distance and direction to a measurement point on the measurement object.

The imaging device 7 is a camera equipped with an image sensor such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) whose light receiving surface, including the imaging surface, is composed of multiple light receiving elements arranged two-dimensionally.

The distance measurement device 6 is provided with an IMU 8. The IMU 8 measures the acceleration and angular velocity of the distance measurement device 6 using a three-directional acceleration sensor 81 and a three-axis gyro sensor 82. The IMU 8 detects the inclination of the distance measurement device 6 based on the measurement results. In other words, it measures the tilt angle in the roll direction, which represents rotation about the xG axis of the global coordinate system, the pitch direction, which represents rotation about the yG axis of the global coordinate system, and the angular displacement in the yaw direction, which represents rotation about the zG axis of the global coordinate system.

The topography measurement device 5, distance measurement device 6, imaging device 7, and IMU 8 constitute a topography measurement system 10. Figure 2 shows a block diagram of the topography measurement system 10.

The terrain measuring device 5 is mounted in the cab 31 of the work machine 1. The terrain measuring device 5 has a distance measuring device 6, an IMU 8 provided in the distance measuring device 6, an imaging device 7, a controller 51, a display unit 52, and an input unit 53. The controller 51, display unit 52, and input unit 53 of the terrain measuring device 5 are configured, for example, by a tablet-type personal computer.

The controller 51 executes various functions of the topographical measuring device 5. The controller 51 has a processing unit 54 and a memory unit 55. The memory unit 55 has a RAM (Random Access Memory) and a ROM (Read Only Memory).

The memory unit 55 stores data on the reference height. The reference height is the height of the target excavation surface when leveling unevenness in the ground. The work machine 1 levels the ground in accordance with the reference height. The reference height is stored in the memory unit 55 by the operator inputting it from the input unit. The memory unit 55 also stores a control program executed by the processing unit 54.

The processing unit 54 includes a CPU and other components, and reads and executes the programs and data stored in the memory unit 55.

The controller 51 acquires distance measurement data of the current topography of the construction site from the distance measurement device 6. The controller 51 displays a distance measurement image of the current topography on the display unit based on the distance measurement data.

The controller 51 also acquires from the IMU 8 tilt angle data in the roll and pitch directions of the distance measuring device 6 and angular displacement data in the yaw direction as attitude information of the distance measuring device 6. The controller 51 performs attitude correction of the distance measuring device 6 based on the acquired tilt angle data and angular displacement data.

The controller 51 also acquires captured image data of the current topography of the construction site from the imaging device 7. The controller 51 superimposes the distance measurement image on the captured image and displays it on the display unit 52.

The display unit 52 is equipped with a display device such as an LCD (Liquid Crystal Display) panel or an organic EL (Electro-Luminescence) panel. The display unit 52 displays screens showing the results of various processes, operation screens, etc.

The input unit 53 is a device for inputting various instructions to the controller 51, and is configured with a touch panel that is operated by directly touching the screen of the display unit 52. The input unit 53 may also be a button, a keyboard, etc.

FIG. 3 shows a functional block diagram of the controller 51. The controller 51 has a distance measurement data acquisition unit 511, an attitude information acquisition unit 512, a captured image acquisition unit 513, a setting unit 514, a distance measurement image generation unit 515, a display control unit 516, a position detection unit 517, a reference point registration unit 518, a reference point detection unit 519, and a correction unit 520.

The distance measurement data acquisition unit 511 acquires point cloud data, which is distance measurement data of the area in front of the cab 31 of the work machine 1 measured by the distance measurement device 6. The attitude information acquisition unit 512 acquires tilt angle data in the roll direction and pitch direction of the distance measurement device 6 measured by the IMU 8, and angular displacement data in the yaw direction, as attitude information of the distance measurement device 6. The captured image acquisition unit 513 acquires an image of the area in front of the cab 31 captured by the imaging device 7.

The setting unit 514 sets a reference height, which is the height of the target excavation surface. The ranging image generating unit 515 generates a ranging image showing the terrain height of the current terrain based on the position information output from the position detecting unit 517 and the reference height set by the setting unit 514. The generated ranging image is an image in which the unevenness of the terrain relative to the set reference height is color-coded according to the difference from the reference height.

The display control unit 516 superimposes the distance measurement image of the unevenness of the terrain in front of the cab 31, generated by the distance measurement image generation unit 515, onto the captured image of the area in front of the cab 31, acquired by the captured image acquisition unit 513, and displays the superimposed image on the display unit 52.

The display image displayed on the display unit 52 by the display control unit 516 by superimposing the distance measurement image on the captured image is shown in FIG. 4. The distance measurement image displays the unevenness of the terrain in different colors according to the difference from the reference height. Area A indicates an area lower in altitude than the reference height, and is displayed in light blue, for example. Area B indicates an appropriate area having the same height as the reference height, and is displayed in green, for example. Area C indicates an area higher in altitude than the reference height, and is displayed in yellow, for example. Area A, which is lower in altitude than the reference height, requires filling to reach the reference height. Area C, which is higher in altitude than the reference height, requires cutting to reach the reference height. Therefore, while checking this display image, the operator can perform leveling work by operating the bucket 43 and blade 50 of the work machine 1 to cut earth from area C and fill earth in area A to eliminate unevenness.

The position detection unit 517 generates three-dimensional coordinates in a local coordinate system, which is the coordinate system of the topographical measurement device 5, based on the point cloud data acquired by the distance measurement data acquisition unit 511. The position detection unit 517 performs attitude correction on the three-dimensional coordinates in the generated local coordinate system based on the attitude information acquired by the attitude information acquisition unit 512, and converts them into three-dimensional coordinates in a global coordinate system based on a reference point set at the construction site. The converted position information is output to the correction unit 520 for correction, and is sent to the distance measurement image generation unit 515.

The reference point registration unit 518 registers the position information of multiple reference points set at the construction site. The reference points are registered by converting local coordinates into global coordinates. In addition, information on the height of the ground, which has been measured in advance using a level or the like, is also registered for each reference point.

The reference point detection unit 519 detects reference points present within an area when scanning the area within a range that can be scanned by the distance measurement device 6, for multiple reference points set by the reference point registration unit 518. When a reference point is detected, a detection signal is sent to the display control unit 516, which displays a mark at a position corresponding to the reference point on the topographical image displayed on the display unit 52. The output of the reference point detection unit 519 is also sent to the correction unit 520.

The correction unit 520 extracts scanning points located near the detected reference point from the point cloud within the scanning area based on the detection signal sent from the reference point detection unit, calculates a correction value from the difference in height coordinate between the reference point and the scanning point, and corrects the height coordinate of the point cloud based on the calculated correction value. The correction unit 520 sends position information of the corrected point cloud to the ranging image generation unit 515. By correcting the height coordinate value, the ranging image generation unit 515 can generate a ranging image that is free of deviations in terms of unevenness relative to the reference height, which is the ground height of the excavation target displayed on the display unit 52. Furthermore, since correction can be performed without using markers, the burden on the CPU due to marker recognition, etc. can be reduced.

Next, the topography measurement by the topography measuring device 5 will be specifically described below.
(Setting the reference point)
Prior to topography measurement by the topography measuring device 5, a first reference point k1 and a plurality of additional reference points, a second reference point k2 through an nth reference point kn, are set within the construction site, and the heights of each reference point ki (i = 1 to n) are measured and stored. When the work machine 1 performs topography measurement while moving, the topography measuring device 5 mounted on the work machine 1 corrects measurement errors by detecting the reference points ki set within the construction site.

The second reference point k2 to the nth reference point kn are provided at positions away from the first reference point k1 and are uniformly arranged within the construction site. For example, as shown in FIG. 5, they are arranged in a grid pattern so that adjacent reference points ki are equidistant from the first reference point k1. The reason for centering the first reference point k1 is to prevent the distance from the first reference point k1 to the furthest position within the construction site from becoming too long and to prevent the measurement error by the topographical measurement device 5 from accumulating and causing a large coordinate shift. In addition, by uniformly arranging multiple reference points ki within the construction site, at least one new reference point ki appears within the scanning area of the distance measurement device 6 each time the work machine 1 moves beyond a predetermined distance range from the reference point ki, and the measurement error is corrected each time.

Here, the operator levels a certain area around each of the first reference point k1 to the nth reference point kn to be set, to a plane of the same height. By leveling the areas around each of the first reference point k1 to the nth reference point kn to a plane of the same height, even if there is some error in the XY direction position coordinates detected by the distance measurement device 6 when generating a distance measurement image of the current topography, the same height can be detected as long as it is within the leveled plane, so there is no change in the Z direction position coordinate. Therefore, no error occurs in the Z direction position coordinate.

The operator uses a level, total station, etc. to measure the heights at the positions of the first reference point k1 and the second reference point k2 to the nth reference point kn, and determines the difference in height between the first reference point k1 and the second reference point k2 to the nth reference point kn. For example, as shown in FIG. 5, when using a level 60 to measure the positions of the first reference point k1 to the nth reference point kn (reference points k1 to k9 in the example of FIG. 5), first, the level 60 is set up on a tripod so that it is horizontal and rotatable around the vertical axis. Next, a staff is set up at each position of the first reference point k1 to the nth reference point kn, the surroundings of which are leveled to a flat plane, and the level is rotated toward the staff to read the scales on the staff, thereby determining the difference in height between the first reference point k1 and the second reference point k2 to the nth reference point kn. The first reference point k1 is leveled in advance so that it is the same as the reference height. Alternatively, the difference from the reference height of the first reference point k1 may be measured. Note that here, for the second reference point k2 to the nth reference point kn, only the altitude difference from the first reference point k1 is obtained, but the three-dimensional coordinates of each reference point ki may be obtained in addition to the altitude difference. The three-dimensional coordinates of each reference point ki may be obtained by measurement, or if the distance and direction between each reference point ki are determined when each reference point ki is set, these may be used to obtain the three-dimensional coordinates.

(Registering reference points)
When the setting of the reference points ki is completed, the work machine 1 moves within the construction site, and the topographical measurement device 5 mounted on the work machine 1 scans the construction site and sequentially registers the reference points ki. Fig. 6 shows the movement of the work machine 1 when registering the reference points ki, and Fig. 7 is a flowchart showing the process of registering the reference points ki.

As shown in FIG. 7, in the reference point registration process, i=1 is set first (step S101). This prepares for the registration of the first reference point k1. The operator operates the work machine 1 to move the work machine 1 to a position where the first reference point k1 is displayed on the screen of the display unit 52 of the topography measuring device 5 (step S102). When the first reference point k1 enters the screen of the display unit 52, the operator stops the work machine 1 and taps the position on the screen where the first reference point k1 is displayed to register the coordinate position of the first reference point k1 (step S103). The distance measuring device 6 measures the distance and direction to the position in the construction site corresponding to the tapped position. Based on the measured distance and direction information, the three-dimensional coordinates (local coordinates) of the position of the first reference point k1 in the coordinate system of the topography measuring device 5 are obtained. The obtained position of the first reference point k1 in the coordinate system of the topography measuring device 5 is attitude-corrected based on the attitude information detected by the IMU 8 and is associated with the global coordinate position. The position of the reference point is registered as three-dimensional coordinates (global coordinates) XYZ coordinate values within the topographical measurement device and stored in the memory unit 55.

Next, the height difference ΔHi between the first reference point k1 and the reference point ki, which was measured in advance using a level or the like in the above-mentioned reference point setting, is registered and stored in the memory unit 55 (step S104). Here, since i=1, ΔHi=0.

When the registration of the first reference point k1 is completed, the controller 51 of the topography measuring device 5 sets the value of the reference point ki to i = i + 1 (step S105). Here, i = 0 + 1 = 1. Next, when the value of i is incremented by 1, it is determined whether the new i reaches the number n of the set reference points ki (step S106). If the value of i has not reached the number n of the reference points ki (step S106: YES), the process returns to step S102, and the operator moves the work machine 1 to a position where the new reference point ki is included on the screen of the display unit 52. Here, the value of i is changed from 0 to 1, and the value of i has not reached the number n of the reference points, so the process returns to step S102, and the operator moves the work machine 1 from the first reference point k1 to a position where the second reference point k2, which is the new reference point, is included on the screen of the display unit.

When the work machine 1 starts moving from the first reference point k1 to the second reference point k2, the distance measurement device 6 resumes scanning and generates point cloud data within the detection range. The controller 51 matches the feature points of the point cloud data of the currently acquired frame with the point cloud data of the previously acquired frame, and detects the amount of movement and direction of movement of the distance measurement device 6 based on the matching results. The self-position of the topography measurement device 5 is updated by accumulating the detected amount of movement and direction of movement. Note that the amount of movement and direction of movement may be obtained based on the detection signals of the acceleration sensor 81 and the gyro sensor 82, and the self-position may be updated.

When the second reference point k2 enters the screen of the display unit 52, the operator stops the work machine 1 and taps the position on the screen where the second reference point k2 is displayed, thereby registering the coordinate position of the second reference point k2 (step S103). The distance measurement device 6 measures the distance and direction to the position in the construction site corresponding to the tapped position. Based on the measured distance and direction information, the self-position of the topographical measurement device 5, the coordinate position of the first reference point k1, and the attitude information, the three-dimensional coordinate values (global coordinates) XYZ of the second reference point k2 are calculated and registered by storing them in the memory unit 55. Furthermore, the controller 51 registers the height difference ΔHi between the first reference point k1 and the second reference point k2, which was measured in advance using a level or the like when setting the reference points, by storing it in the memory unit 55 (step S104).

When the registration of the second reference point k2 is completed, the controller 51 increments the value of i by 1 (step S105) and determines whether i has reached the number n of reference points ki (step S106). If the value of i has not reached the number n of reference points (step S105: YES), the process returns to step S102 and repeats the processes from step S102 onwards. If the value of i has reached the number n of reference points (step S105: NO), the reference point registration process ends.

(topography)
Once the registration of the reference points ki in the topography measuring device 5 is completed, preparations for topography measurement during ground excavation work are completed, and while the ground excavation work is actually being performed, the topography measuring device 5 executes topography measurement and displays a distance measurement image on the display unit 52.

The excavation work is started after the work machine 1 is moved and the topography measuring device 5 detects the first reference point k1. The topography measuring device 5 generates a distance measurement image showing the topography height of the current topography based on the distance measurement data whose attitude is corrected based on the position of the first reference point k1. The work machine 1 moves to the excavation work site and moves away from the first reference point k1, but the coordinates of the topography are continuously obtained by obtaining changes in the characteristic points of the point cloud data obtained from the distance measuring device 6 and integrating them with the position coordinates of the first reference point k1. Here, in order to prevent errors from accumulating and the coordinate shift from increasing when the moving distance is large, it is possible to install a marker whose positional relationship with the reference point ki is known at a position away from the first reference point k1, recognize the marker, and correct the position error based on the recognized marker. However, in actual construction, what is required of the topography measuring device 5 is the accuracy of the topography height, and the accuracy on the horizontal plane (XY) is not as important as the height. Therefore, in the topography measurement in this embodiment, the XY position shift is ignored and only the height is corrected. This reduces the CPU load required to recognize markers.

8 shows the point cloud positions and the position of the reference point ki detected by the distance measuring device 6 during topography measurement, and FIG. 9 is a flow chart showing the process of correcting the Z position, which is the coordinate position of the point cloud in the height direction, during topography measurement. As shown in FIG. 9, the distance measuring device 6 of the topography measuring device 5 scans a detectable area to obtain point cloud data and create the coordinates (Xj, Yj, Zj) of the point cloud (step S201). The positions of each scanning point of the point cloud at this time are shown by black squares in FIG. 8, and the reference point ki exists within the scanning area. When the distance measuring device 6 scans an area that can be irradiated, the controller 51 determines whether or not the reference point ki exists within the area, i.e., whether or not the reference point ki is within the screen of the display unit 52 of the topography measuring device 5 (step S202). If the reference point ki is present within the area (step S202: YES), the controller 51 displays a three-dimensional mark, such as a cone, on the screen of the display unit 52 using AR (Augmented Reality) (step S203) to enable the operator to determine the position of the reference point ki. If the reference point ki is not present within the area (step S202: NO), the process returns to step S201, and the distance measurement device 6 continues to scan the area that can be irradiated.

Next, the distance Lij between the XY coordinates of the point cloud and the XY coordinates of the reference point ki that exists within the detection range of the distance measurement device 6 is calculated, and the combination of the scanning point j and the reference point ki that minimizes the distance Lij is determined (step S204). The distance Lij is calculated from the coordinates (Xj, Yj, Zj) of the point cloud scanned by the distance measurement device and the XY coordinates of the coordinates (Xi, Yi, Zi) of the reference point ki that was previously registered, using the following formula (1).

The minimum distance Lij between the obtained scanning point j and the reference point ki is compared with a predetermined distance value Lmax to determine whether the scanning point j is in the vicinity of the reference point ki (step S205). Here, the distance Lmax is the maximum value of the range in which the deviation of the XY coordinates of the point cloud is tolerable, and is set within a certain distance range from the reference point ki that has been leveled to the same height as the reference point when measuring the reference point using a level or the like. Preferably, the distance Lmax is about several centimeters. In Figure 8, the range of the distance Lmax from the reference point ki is shown by a dotted line. When the minimum distance Lij between the scanning point j and the reference point ki is within the range of Lmax from the reference point ki (step S205: YES), the deviation amount ΔZ of the Z-axis coordinate of the scanning point j is calculated from the Z-axis coordinate Zj of the scanning point j detected by the topographical measurement device 5 and the altitude difference ΔHi of the reference point ki measured and registered in advance relative to the first reference point k1 (step S206). Zj is a deviation in the coordinate due to accumulated errors caused by the movement of the work machine 1. This deviation amount ΔZ is calculated using the following formula (2).

ΔZ=ΔHi-(Zj-Z1)...(2)

Here, Z1 is the Z-axis coordinate of the first reference point k1. Once ΔZ is found, it is used as the correction amount for the Z coordinate of the point cloud. Therefore, for all scanning points of the point cloud scanned by the distance measurement device 6, the Z coordinate is corrected to (Zj + ΔZ) (step S207). On the other hand, in step S203, if the minimum distance Lij between scanning point j and reference point ki does not exist within the range of Lmax from reference point ki, that is, if no scanning point is found in the vicinity of reference point ki (step S203: NO), the correction amount is not updated, and the most recently calculated correction amount ΔZ is continued to be used to correct the Z coordinate to (Zj + ΔZ) (step S207).

In the above embodiment, since the exact XY coordinates of the point cloud are not obtained, no markers are required, and instead of the marker recognition process, a process is performed to determine whether the scanning point j is in the vicinity of the reference point ki, which reduces the CPU load compared to the marker recognition process and has little effect on the topography measurement process. In addition, when performing Z correction, the operator only needs to operate the position and orientation of the work machine 1 so that the three-dimensional mark representing the reference point ki appears on the screen, and the coordinates are automatically corrected, so there is no need to instruct the topography measurement device 5 to specify the reference point ki or to execute correction. As described above, the above topography measurement process is performed until the excavation work at the construction site is completed. Then, if the reference point within the construction site is also constructed and the height is adjusted, the registration of the reference point is canceled before construction. Note that, although multiple reference points ki are used in the above embodiment, there may be only one reference point ki.

Second Embodiment
In the above embodiment, before the topography measuring device 5 registers the reference points ki, the reference points ki are measured using a level, etc. In the second embodiment, the topography measuring device 5 measures the reference points ki and registers the reference points ki without measuring the reference points ki using a level, etc.

FIG. 10 shows the movement of the work machine 1 when setting and registering the reference point ki. Also, FIG. 11 is a flowchart showing the process of setting and registering the reference point. First, set i=1 (step S301), and move the work machine 1 to a position where the first reference point k1 is on the screen of the display unit 52, that is, a position that exists in the scanning area of the distance measurement device 6 (step S302). When the first reference point k1 is on the screen of the display unit 52, the operator stops the work machine 1. FIG. 10A shows a state where the first reference point k1 is on the screen of the display unit 52 and the work machine 1 is stopped. In this state, the operator taps the position on the screen where the first reference point k1 is displayed to register the coordinate position of the first reference point k1 (step S303). Here, the surroundings of the first reference point k1 are leveled in advance to the same height as the reference height. The distance measurement device 6 measures the distance and direction to the position of the construction site corresponding to the tapped position. Based on the measured distance and direction information, the three-dimensional coordinates (local coordinates) of the position of the first reference point k1 in the coordinate system of the topography measuring device 5 are obtained. The position of the first reference point k1 in the coordinate system of the topography measuring device 5 is attitude-corrected based on the attitude information detected by the IMU 8 and associated with a global coordinate position. The position of the reference point k1 is registered as three-dimensional coordinates (global coordinates) XYZ coordinate values within the topography measuring device 5.

When registration of the first reference point k1 is completed, i = i + 1 is set (step S304). Here, i = 1 + 1 = 2. When the value of i is incremented by 1, it is determined whether the new i has reached the number n of reference points ki (step S305). If the value of i has not reached the number n of reference points ki (step S305: YES), it is then determined whether the rotating body 3 of the work machine 1 is positioned in a state where it has been rotated backward (step S306). The determination of whether it is positioned backward is made, for example, based on the detection signal of the IMU 8 or information regarding the rotation position of the rotating body 3 obtained by the controller 51 from the work machine 1.

If the rotating body 3 is not located rearward (step S306: NO), the work machine 1 rotates the rotating body 3 rearward while remaining at the position where the first reference point k1 was registered (step S308). Here, the value of i is changed from 1 to 2, and since the value of i has not reached the number n of reference points ki, the rotating body 3 is rotated rearward. Figure 10B shows the state in which the rotating body 3 of the work machine 1 has been rotated rearward. The part shown in dashed lines is the rotating body 3 and the work machine 4, and shows the state before the rotating body 3 is rotated. The rotating body 3 and the work machine 4 that have been rotated rearward are shown in solid lines, and the work machine 4 is heading toward the position that will be the second reference point k2.

Then, the work machine 4 is operated to excavate a certain range around the position to be the second reference point k2 with the bucket 43, and the ground is leveled to the same height as the first reference point k1 (step S309). Here, since the work machine 1 remains stopped, the self-position and attitude of the topography measurement device 5 do not change. Therefore, the distance measurement device 6 can measure the difference in height with the first reference point k1, and excavation is performed to eliminate this difference in height. The certain range is the same width as in the first embodiment, and is the range in which the deviation of the XY coordinates of the scanning point relative to the second reference point k2 during topography measurement is acceptable. When excavation is completed, the excavation position displayed on the screen is tapped to register the coordinate position of the second reference point k2 (step S303). As described above, since the work machine 1 remains stopped, the coordinates of the self-position of the topography measurement device 5 remain at the origin. The distance measurement device 6 measures the distance and direction to the position of the construction site corresponding to the tapped position. Based on the measured distance and direction information, the self-position of the distance measurement device 6, the coordinate position of the first reference point k1, and the attitude information, the three-dimensional coordinates (global coordinates) XYZ of the second reference point k2 are calculated and registered by being stored in the memory unit 55.

When the registration of the second reference point k2 is completed, i is set to i+1 (step S304). Here, i=2+1=3. When the value of i is incremented by 1, it is determined whether the new i has reached the number n of reference points ki (step S305).

If the value of i does not reach the number of reference points (step S305: YES), it is then determined whether the rotating body 3 of the work machine 1 is in a state where it has been rotated backward (step S306). Here, since the rotating body 3 is in a state where it is in a backward position, step S306 is determined as YES, and the rotating body 3 that has been rotated backward is returned to its original position, and the work machine 1 is moved backward (step S307). The work machine 1 is stopped when it passes the position of the second reference point k2 and reaches a position where the second reference point k2 appears on the screen of the display unit 52 of the topography measuring device 5. FIG. 10C shows a state where the rotating body 3 has been returned to its original position and the work machine 1 has been moved backward. The part indicated by the dashed line shows the work machine 1 in a state where the rotating body 3 has been returned to its original position, and the part indicated by the solid line shows the work machine 1 in a state where it has been moved backward.

The distance measuring device 6 of the topography measuring device 5 measures the distance from the stopped position to the second reference point k2 and identifies the coordinates of its own position. Next, the work machine is rotated backward (step S308). Here, the value of i is changed from 2 to 3, and the value of i does not reach the n number of the reference point ki, so the rotating body 3 is rotated backward, and then, a certain range around the position to be the third reference point k3 is excavated to the same height as the first reference point k1 by the bucket 43 to level the ground (step S309). Figure 10D shows the state in which the rotating body 3 of the work machine has been rotated backward. The part shown in dashed lines is the rotating body 3 and the work machine 4, and shows the state before the rotating body 3 is rotated. The rotating body 3 and the work machine 4 that have been rotated backward are shown in solid lines, and the work machine 4 is heading toward the position to be the third reference point k3. Here, since the work machine 1 remains stopped, the self-position and attitude of the topography measuring device 5 do not change. The height of the second reference point k2 is the same as the height of the first reference point k1. Therefore, the distance measuring device 6 can measure the difference in height with the second reference point k2, and excavation is performed to eliminate this difference in height, so that the ground is leveled to the same height as the first reference point k1. When excavation is completed, the excavation position displayed on the screen is tapped to register the coordinate position of the third reference point k3 (step S303). The distance measuring device 6 measures the distance and direction to the position of the construction site corresponding to the tapped position. Based on the measured distance and direction information, the self-position of the distance measuring device 6, the coordinate position of the first reference point k1, and the attitude information, the three-dimensional coordinates (global coordinates) XYZ coordinate values of the third reference point k3 are calculated and registered by storing them in the memory unit 55.

When the registration of the third reference point k3 is completed, i = i + 1 is set (step S304). When the value of i is incremented by 1, it is determined whether the new i has reached the number n of reference points ki (step S305). If the value of i has not reached the number of reference points (step S305: YES), it is then determined whether the rotating body 3 of the work machine 1 is located in a state of being rotated backward (step S306). If it is located backward (step S306: YES), the rotating body 3 that has been rotated backward is returned to its original position, the work machine 1 is moved backward (step S307), and the process proceeds to step S308. Also, if the rotating body 3 is not located backward in step S306 (step S306: NO), the process proceeds to step S308. When the ground around the reference point ki is leveled in step S308, the process returns to step S303 and the process from step S303 onwards is repeated. Then, in step S305, if the value of i reaches the number n of reference points ki (step S305: NO), the reference point setting and registration process ends.

In the above example, multiple other reference points ki are set in the column direction from the first reference point k1. After the reference point ki in the first column is set, the work machine 1 is moved in the row direction to set the reference point ki in the second column, and the reference points ki in the third column and onward are set in the same manner, thereby allowing multiple reference points ki to be set on the XY plane. Here, when setting the reference point ki in the second column, the rotating body 3 may first be rotated to a position where the first reference point k1 is within the screen of the display unit 52, the self-position of the work machine 1 is confirmed, and then the rotating body 3 may be rotated in the opposite direction to set the first reference point ki in the second column. This allows the ground to be leveled to the same height as the first reference point k1. For the third column and onward, the rotating body 3 may be rotated to a position where the reference point ki in the previous column is within the screen of the display unit 52, the self-position of the work machine 1 is confirmed, and then the rotating body 3 may be rotated in the opposite direction to set the reference point ki in the own column.

Furthermore, the travel angle of the work machine 1 may be changed around the first reference point k1, and multiple reference points ki may be set by repeatedly rotating the rotating body 3 backward and moving the work machine 1 backward for each travel angle, as in the above example.

In the above example, after the reference point ki is registered, the revolving body 3 is rotated 180 degrees backward to register a new reference point ki, but the angle of rotation is not limited to this. For example, after the reference point ki is registered, the revolving body 3 may be rotated 90 degrees to the right or 90 degrees to the left, and then the area in front of the work implement 4 may be excavated and leveled, and then a new reference point ki may be registered. When a new reference point ki is registered to the right, the work machine 1 returns the revolving body 3 to its original position, rotates 90 degrees to the left to change the travel angle, starts moving backward, and stops when it passes the newly registered reference point ki and reaches a position where the reference point ki appears on the screen of the display unit 52. When the topography measuring device 5 measures the distance to the reference point ki in a stopped state and identifies its own position, the revolving body 3 is rotated 180 degrees backward, and the surrounding area is excavated and leveled to set a new reference point ki further to the right of the reference point ki, and then the new reference point ki is registered. Furthermore, if a new reference point ki is registered to the left, the work machine 1 returns the rotating unit 3 to its original position, rotates 90 degrees to the right to change the travel angle, then starts moving backward, passing the newly registered reference point ki and stopping when it reaches a position where the reference point appears on the screen of the display unit 52. When the work machine 1 is stopped, the topography measuring device 5 measures the distance to the reference point ki and identifies its own position, the rotating unit 3 rotates 180 degrees backward, excavates and levels the surrounding area to set a new reference point ki further to the left of the reference point ki, and then registers the new reference point ki.

In the above embodiment, LiDAR is used as the distance measurement device 6, but this is not limited to this and may be, for example, a stereo camera, a TOF camera, etc.

When realizing this by a computer, for example, the program executed by the processing unit 54 can be stored in a non-transitory computer-readable recording medium, distributed, and the program can be installed on a computer to configure a device that executes the above-mentioned processing. Examples of such recording media include CD-ROMs (Compact Disc Read-Only Memory) and DVDs (Digital Versatile Discs).

The program may also be stored on a disk device in a server device on a communication network such as the Internet, and then downloaded to a computer, for example by superimposing it on a carrier wave.

The above process can also be achieved by launching and executing a program while transferring it via a communications network.

Furthermore, the above-mentioned processing can also be achieved by executing all or part of the program on a server device and having a computer execute the program while sending and receiving information related to the processing via a communications network.

In addition, when the above-mentioned functions are shared and realized by the OS (Operating System) or by the OS working together with an application, etc., only the parts other than the OS may be stored on a medium and distributed, or may be downloaded to a computer.

In addition, the means for realizing the above-mentioned functions are not limited to software, but may be realized in part or in whole by dedicated hardware including circuits.

The present invention allows for various embodiments and modifications without departing from the broad spirit and scope of the present invention. Furthermore, the above-described embodiments are intended to explain the present invention and do not limit the scope of the present invention. In other words, the scope of the present invention is indicated by the claims, not the embodiments. Furthermore, various modifications made within the scope of the claims and within the meaning of the disclosure equivalent thereto are considered to be within the scope of the present invention.

The present invention can be widely applied to topographical measurement devices installed on work machines.

1. Work machine, 2. Traveling body, 3. Swinging body, 4. Work machine, 5. Terrain measurement device, 6. Distance measurement device, 7. Imaging device, 8. IMU, 9. Geomagnetic sensor, 10. Terrain measurement system, 31. Cab, 32. Operation device, 41. Boom, 42. Arm, 43. Bucket, 44. Boom pin, 45. Boom cylinder, 46. Arm pin, 47. Arm cylinder, 48. Bucket pin, 49. Bucket cylinder 50 Blade, 51 Controller, 52 Display unit, 53 Input unit, 54 Processing unit, 55 Memory unit, 81 Acceleration sensor, 82 Gyro sensor, 511 Distance measurement data acquisition unit, 512 Attitude information acquisition unit, 513 Captured image acquisition unit, 514 Setting unit, 515 Distance measurement image generation unit, 516 Display control unit, 517 Position detection unit, 518 Reference point registration unit, 519 Reference point detection unit, 520 Correction unit.

Claims (12)

A topographical measurement device that is mounted on a moving body and measures the shape of the ground at a construction site,
a reference point registration unit in which position information of at least one reference point within the construction site is registered;
a position detection unit that detects a position of the point cloud in a global coordinate system based on point cloud data acquired from a distance measurement device that measures a distance to the ground;
a display unit that displays a distance measurement image of an area scanned by the distance measurement device;
a reference point detection unit that detects a reference point that exists within the area among the at least one reference point;
a correction unit that extracts, from the point cloud present within the area, a scanning point that has a minimum horizontal distance from the reference point detected by the reference point detection unit and is within a predetermined distance, and corrects the height coordinate of the point cloud based on a correction value calculated from a height coordinate difference from the reference point;
A topographical measuring device comprising: the at least one reference point is a first reference point and second to n-th reference points that are in a predetermined positional relationship with the first reference point, and the global coordinate system is a coordinate system fixed to the first reference point;
2. The topographical measuring device according to claim 1. the reference point registration unit, by designating positions of the at least one or more reference points on the screen of the display unit as the position information, converts the designated positions from a local coordinate system to a global coordinate system and registers the designated positions, and also registers a position in a height direction that has been measured in advance;
2. The topographical measuring device according to claim 1. the reference point registration unit, by specifying a position of a first reference point among the at least one or more reference points on the screen of the display unit, converts the position of the first reference point from a local coordinate system to a global coordinate system and registers the position; and, by specifying positions of a second to an n-th reference point among the at least one or more reference points on the screen, converts the positions of the second to the n-th reference points from the local coordinate system to a global coordinate system and registers the positions; and registers coordinate differences in height direction from the first reference point that have been measured in advance for the second to the n-th reference points.
3. The topographical measuring device according to claim 2. when the reference point is detected by the reference point detection unit, the display unit displays a mark at a position on the screen corresponding to the reference point.
2. The topographical measuring device according to claim 1. When the correction value has not been calculated, the correction unit maintains the correction based on the most recently calculated correction value.
2. The topographical measuring device according to claim 1. The predetermined distance is a distance within a range that is leveled to the same height and has each of the at least one or more reference points as a center.
2. The topographical measuring device according to claim 1. A topographical measuring device according to claim 1;
A distance measuring device;
A topographical measurement system comprising: The vehicle includes a running body and a rotating body that can rotate on the running body,
The topographical measurement system according to claim 8 is mounted on the rotating body.
Working machinery. 2. The method for setting and registering a reference point in a topographical measuring device according to claim 1, further comprising the steps of:
A first step in which the topographical measuring device measures distances and registers a first reference point;
a second step of rotating the topography measuring device, measuring the distance to the ground, leveling the ground to the same height as the first reference point, and then registering a second reference point at the leveled position;
a third step of moving the topographical measuring device to a position where the distance to the second reference point can be measured;
repeating the second and third steps for the third to n-th reference points in the same manner as for the second reference point;
How to register reference points. A topographical measurement method for measuring the shape of the ground at a construction site using a topographical measurement device mounted on a moving body, comprising:
acquiring point cloud data from a distance measuring device that measures a distance to the ground, and detecting a position of the point cloud in a global coordinate system based on the point cloud data;
A step of detecting a reference point that exists within an area scanned by the distance measuring device from among at least one reference point whose position information is registered in advance within the construction site;
extracting a scanning point that has a minimum horizontal distance from the detected reference point and is within a predetermined distance from the point cloud present within the area, and correcting the height coordinate of the point cloud based on a correction value calculated from a height coordinate difference from the reference point;
A topographical measurement method comprising: On the computer,
A step of acquiring point cloud data from a distance measuring device that measures a distance to the ground in a construction site, and detecting a position of the point cloud in a global coordinate system based on the point cloud data;
A step of detecting a reference point that exists within an area scanned by the distance measuring device from among at least one reference point whose position information is registered in advance within the construction site;
extracting a scanning point that has a minimum horizontal distance from the detected reference point and is within a predetermined distance from the point cloud present within the area, and correcting the height coordinate of the point cloud based on a correction value calculated from a height coordinate difference from the reference point;
A program that executes the following.