Calibration device, method for calibration, and storage medium

Abstract

To provide a calibration device and the like capable of effectively correcting installation data of a distance measuring sensor.SOLUTION: A calibration device 300 includes: a distance measuring point cloud acquisition unit 310 configured to acquire a distance measuring point cloud on a measurement target object by distance measuring sensors 18 and 19 installed on a CSU1 as a work machine; a coordinate conversion unit 330 configured to convert the distance measuring point cloud into coordinates in a reference coordinate system relating to the CSU1, on the basis of installation data α of the distance measuring sensors 18 and 19; a shape feature detection unit 360 configured to detect the shape feature of the measurement target object on the basis of the distance measuring point cloud in the reference coordinate system; and an installation data correction unit 380 configured to correct the installation data α so that the error between the shape feature and the distance measuring point cloud becomes small.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a calibration device for a distance measurement sensor installed on a work machine. [Background technology]

[0002] Cargo handling machines that load and unload cargo, which is the cargo or cargo of a ship, are known as work machines that perform various tasks. Cargo handling machines are broadly divided into loading machines that load cargo into a ship's hold and unloading machines that unload cargo from the hold to land. Loading machines that load bulk cargo or bulk materials, such as coal and iron ore, are also called ship loaders, and unloading machines that unload bulk materials are also called ship unloaders. This disclosure is applicable to any work machine or cargo handling machine, but will mainly be described as an example and representative of unloading machines or ship unloaders. Some ship unloaders continuously unload bulk materials from a ship's hold and are called continuous unloaders or continuous ship unloaders. In this disclosure, the abbreviation CSU is used.

[0003] Patent Document 1 discloses a technology for deriving the relative position of a ship unloader and a ship based on the results of edge detection of the upper part of a hold by a distance measurement sensor (laser sensor). In this technology, the edge of the hold is detected based on a series of distance measurement points acquired by the distance measurement sensor using laser light that is continuously irradiated onto the upper surface and side wall surface facing the edge of the hold. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-131394 Summary of the Invention [Problem to be solved by the invention]

[0005] The ranging point cloud acquired by the ranging sensor is a coordinate (hereinafter also referred to as ranging unit coordinates) in a coordinate system (hereinafter also referred to as ranging unit coordinate system) with the ranging sensor as the origin. To enable the CSU to use this ranging point cloud, the ranging unit coordinates are converted into coordinates (hereinafter also referred to as reference coordinates) in a coordinate system related to the CSU (hereinafter also referred to as reference coordinate system) based on the position and orientation at which the ranging sensor is installed on the CSU. To obtain accurate reference coordinates, the installation data (position and / or orientation) of the ranging sensor used for coordinate conversion from the ranging unit coordinate system to the reference coordinate system must be accurate.

[0006] The present disclosure has been made in consideration of these circumstances, and aims to provide a calibration device and the like that can effectively correct installation data of a distance measurement sensor. [Means for solving the problem]

[0007] In order to solve the above problems, a calibration device of one aspect of the present disclosure includes a ranging point cloud acquisition unit that acquires a ranging point cloud on a measurement object using a ranging sensor installed on a work machine, a coordinate conversion unit that converts the ranging point cloud into coordinates in a reference coordinate system related to the work machine based on installation data of the ranging sensor, a shape feature detection unit that detects shape features of the measurement object based on the ranging point cloud in the reference coordinate system, and an installation data correction unit that corrects the installation data so as to reduce errors between the shape features and the ranging point cloud.

[0008] According to this aspect, the installation data of the distance measurement sensor can be effectively corrected by utilizing the shape features detected based on the distance measurement point group on any measurement object.

[0009] Another aspect of the present disclosure is a calibration method that includes acquiring a range point cloud on a measurement object using a range sensor installed on a work machine, converting the range point cloud into coordinates in a reference coordinate system related to the work machine based on installation data of the range sensor, detecting shape features of the measurement object based on the range point cloud in the reference coordinate system, and correcting the installation data so as to reduce an error between the shape features and the range point cloud.

[0010] Yet another aspect of the present disclosure is a storage medium that stores a calibration program that causes a computer to acquire a range point cloud on a measurement object using a range sensor installed on a work machine, convert the range point cloud into coordinates in a reference coordinate system related to the work machine based on installation data of the range sensor, detect shape features of the measurement object based on the range point cloud in the reference coordinate system, and correct the installation data so as to reduce an error between the shape features and the range point cloud.

[0011] Any combination of the above components, or any conversion of these expressions into methods, devices, systems, recording media, computer programs, etc., are also encompassed within the present disclosure. [Effects of the Invention]

[0012] According to the present disclosure, the installation data of the distance measurement sensor can be effectively corrected. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a front view showing the overall configuration of a lifting machine. FIG. [Figure 2] FIG. 1 is a perspective view showing the overall configuration of a lifting machine. [Figure 3] The detailed configuration of the loading section is shown. [Figure 4] The external appearance of the distance measurement sensor is shown. [Figure 5] FIG. 10 is a top view showing an example of the arrangement of distance measurement sensors. [Figure 6]FIG. 2 is a schematic functional block diagram of a calibration device. [Figure 7] 10A-10C show schematic diagrams of various coordinate systems that can be established for a CSU; [Figure 8] 1 shows an example of a computer operation screen. [Figure 9] 10 is a flowchart illustrating an example of calibration of a distance measuring sensor by a calibration device. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments for carrying out the present disclosure (hereinafter also referred to as embodiments) will be described in detail with reference to the drawings. In the description and / or drawings, identical or equivalent components, members, processes, etc. are designated by the same reference numerals, and redundant description will be omitted. The scale and shape of each part shown in the drawings are set for convenience to simplify the description and should not be construed as limiting unless otherwise specified. The embodiments are merely examples and do not limit the scope of the present disclosure in any way. Not all features and combinations thereof presented in the embodiments are necessarily essential to the present disclosure. For convenience, the embodiments are presented by breaking them down into components for each function and / or functional group that realize them. However, one component in an embodiment may actually be realized by a combination of multiple separate components, or multiple components in an embodiment may actually be realized by a single integrated component. Furthermore, although multiple embodiments and variants may be disclosed in parallel, any components of each embodiment and / or each variant may be combined in any manner as long as they do not interfere with each other's functions.

[0015] FIG. 1 shows the overall configuration of a lifting machine 1 as a work machine or cargo handling machine according to an embodiment of the present disclosure. The lifting machine 1 is a continuous unloader or a continuous ship unloader that unloads bulk material M as cargo or ship cargo loaded on a ship 200 onto land. Hereinafter, the lifting machine 1 will also be referred to as a CSU 1. The CSU 1 continuously carries out onto land bulk material M stored in a hold 201 of a ship 200 that is berthed at a quay 101 of a wharf 102 of a port or the like. Typical examples of bulk material M include coal, coke, ore, etc.

[0016] The CSU1 is operated by an operator in a main control room 16 provided in the main body of the CSU1. The control room for operating the CSU1 may be provided elsewhere within the CSU1, or may be provided at any location on land outside the CSU1.

[0017] The wharf 102 where the ship 200 docks constitutes land where bulk cargo M is unloaded and is made of high-strength materials such as reinforced concrete. As shown in the perspective view of FIG. 2, the wharf 102 is provided with a pair of parallel rails 3 as tracks that run along the longitudinal direction (perpendicular to the plane of the paper in FIG. 1) of the ship 200 docked and anchored at the quay 101. The rails 3 form a track along which the traveling unit 2, which serves as the mobile unit of the CSU 1, can move or run. The rails 3 enable the CSU 1 to move relative to the anchored ship 200. As shown in FIG. 2, the installation direction of the rails 3 preferably coincides with the longitudinal direction of the anchored ship 200 or the quay 101, but may be any other direction. The rails 3 may also include curved or bent portions. When unloading cargo from the ship 200, the CSU 1 moves on the rails 3 and approaches a hatch 21, which serves as an upper opening of the hold 201 from which cargo is to be unloaded. Thereafter, the traveling section 2, the swivel frame 5, the lifting section 9, etc. are driven, and the bulk cargo M is lifted from the hold 201.

[0018] At the wharf 102, a belt conveyor 45 is provided between the pair of rails 3 as a conveyor for transporting the unloaded bulk goods M in a certain direction. As shown in FIG. 2, the installation direction of the belt conveyor 45, i.e., the transport direction, preferably coincides with the installation direction of the rails 3, but may be any other direction. The belt conveyor 45 may also include curved or bent portions. The belt conveyor 45 needs to be provided between the pair of rails 3 at the location where the bulk goods M unloaded from the CSU 1 are received, but may be provided outside the pair of rails 3 at other locations.

[0019] The CSU 1 comprises a traveling section 2 as a moving section that can move relative to the ship 200, a swivel frame 5 as a rotating section that can rotate relative to the traveling section 2, and a lifting section 9 as a cargo handling or lifting device that is provided at the tip of the swivel frame 5 and transports bulk cargo M. The swivel frame 5 is supported on the traveling section 2 so as to be rotatable about a rotation axis in the vertical direction (the up and down direction in FIG. 1). The swivel frame 5 is provided with a boom 7 that extends laterally and intersects with the rotation axis, and a bucket elevator that serves as a transport section that constitutes the main part of the lifting section 9 is supported at the tip of the boom 7.

[0020] The lifting unit 9 maintains a vertical position regardless of the boom 7's hoisting angle (the angle of rotation around the hoisting axis perpendicular to the plane of the page in FIG. 1) thanks to a parallel link mechanism formed between the swivel frame 5, boom 7, and parallel link 8. A counterweight 13 is attached to the rear end of the swivel frame 5, opposite the tip of the boom 7. The counterweight 13 is connected to the tip of the boom 7 via a balancing lever 12. The action of this counterweight 13 places the lifting unit 9 in a substantially unloaded state, achieving a stable load balance. The main components of the swivel unit, such as the swivel frame 5, boom 7, balancing lever 12, and counterweight 13, are hereinafter collectively referred to as the main body.

[0021] A cylinder 15 is provided to adjust the boom 7's hoisting angle. When the cylinder 15 is at its standard length, the hoisting angle is 0 degrees, i.e., the boom 7 is parallel or horizontal to the ground (left-right direction in Figure 1). When the cylinder 15 is extended beyond its standard length, the tip of the boom 7 rises, resulting in a positive hoisting angle. When the cylinder 15 is retracted beyond its standard length, the tip of the boom 7 descends, resulting in a negative hoisting angle. The lifting unit 9 supported at the tip of the boom 7 rises while maintaining a vertical position when the boom 7's hoisting angle increases, and descends while maintaining a vertical position when the boom 7's hoisting angle decreases. In this way, the lifting unit 9, which functions as a cargo handling or lifting device, moves up and down integrally with the boom 7 in accordance with the hoisting of the boom 7.

[0022] A main control room 16 for operating the CSU 1 is provided in the main body of the CSU 1 or the rotating unit. In the example of FIG. 1, the main control room 16 is provided on the unloading unit 9 side of the revolving frame 5. An operator in the main control room 16 can safely operate the CSU 1 while visually checking the unloading unit 9. The operator in the main control room 16 may also operate the CSU 1 while viewing on a monitor an image or video of the inside of the hold 201 captured by a photographing device such as a camera. Parameters related to the position, attitude, operation, etc. of the CSU 1, such as the position of the traveling unit 2, the rotation angle of the revolving frame 5, and the hoisting angle of the boom 7 (hereinafter collectively referred to as the CSU state), are controlled in response to operation of the CSU 1 through the main control room 16. The unloading operation of the unloading unit 9 for bulk cargo M can also be controlled through the main control room 16.

[0023] The unloading section 9 includes a scraping section 11 as a handling section that scrapes bulk goods M from within the hold 201, and a bucket elevator as a transport section that transports the bulk goods M scraped by the scraping section 11 upward and out of the hold 201. The scraping section 11 is provided at the bottom of the unloading section 9. The bulk goods M from the hold 201 are continuously excavated and scraped away by a number of buckets 27 (see FIG. 3) that are provided movably in a single direction (W in FIG. 1) along the outer periphery of the scraping section 11. The bulk goods M scraped by the scraping section 11 are transported upward together with the buckets 27 by the bucket elevator.

[0024] Fig. 3 shows a detailed configuration of the unloading unit 9. The bucket elevator comprises a cylindrical elevator body 14 extending vertically, and a chain bucket 29 that moves in circles along the outer periphery of the elevator body 14 and the scraping unit 11. The chain bucket 29 comprises a pair of roller chains 25, each of which is an endless chain, and a plurality of buckets 27, both sides of which are supported by the pair of roller chains 25. Specifically, the pair of roller chains 25 are arranged side by side in a direction perpendicular to the plane of the paper in Fig. 3(B), and each bucket 27 is attached so as to be suspended between the pair of roller chains 25.

[0025] The bucket elevator includes a drive roller 31a that rotates the roller chain 25 that is stretched across it, driven rollers 31b and 31c, and a diverting roller 33. The drive roller 31a is provided at the top 9a of the bucket elevator and is driven to rotate by a motor (not shown) or the like, causing the chain bucket 29 to move in a circular motion. The driven roller 31b is provided in front of the scraping unit 11 (left side in FIG. 3(B)), and the driven roller 31c is provided behind the scraping unit 11 (right side in FIG. 3(B)), and each guides the circularly moving chain bucket 29. The diverting roller 33 is a driven roller provided below the drive roller 31a, and guides the circularly moving chain bucket 29 and changes its direction of movement. An extendable cylinder 35 is provided between the driven rollers 31b and 31c. When this cylinder 35 extends or retracts, the distance between the axes of the driven rollers 31b, 31c changes, thereby changing the trajectory of the orbital motion of the chain bucket 29. Control of extension and retraction of the cylinder 35 may be performed in response to operations via the main operation room 16, or may be performed automatically according to a program by a computer built into the CSU 1. Since two roller chains 25 are provided, two each of the drive roller 31a, driven rollers 31b, 31c, and deflection roller 33 are also provided, and are arranged side by side in a direction perpendicular to the plane of the paper in Figure 3(B).

[0026] By being rotationally driven through the drive roller 31a, the chain bucket 29 moves in an orbit around the outer periphery of the elevator body 14 and the scraping part 11. For example, the chain bucket 29 moves in an orbit counterclockwise direction along the arrow W shown in FIG. 3(B). At this time, the chain bucket 29 moves back and forth between the scraping part 11 provided at the bottom of the bucket elevator and the drive roller 31a provided at the top 9a of the bucket elevator.

[0027] Each bucket 27 of the chain bucket 29 rises along the elevator body 14 while maintaining its orientation with its opening facing upward. When each bucket 27 passes over the drive roller 31a at the top 9a of the bucket elevator, its direction of movement changes from upward to downward, and the opening of each bucket 27 also turns from upward to downward. A discharge chute (not shown) is provided below the opening of each bucket 27 that has turned downward in this manner, and the bulk goods M scraped by each bucket 27 are discharged there. The discharge chute discharges the bulk goods M onto a rotary feeder 37 (FIG. 1) provided on the outer periphery of the upper part of the unloading section 9.

[0028] The rotary feeder 37 rotates around a rotation axis in the extension direction of the elevator body 14, i.e., the vertical direction, and transfers the bulk goods M discharged from the discharge chute to a boom conveyor 39 of the boom 7. The boom conveyor 39 transports the bulk goods M along the boom 7 to the vicinity of the rotation axis of the rotating frame 5 and supplies them to a hopper (not shown) provided there. An internal conveyor 43 that receives the bulk goods M is provided in the running section 2 below the discharge opening of this hopper. The internal conveyor 43 transfers the bulk goods M to the aforementioned belt conveyor 45 provided on the pier 102, which serves as land.

[0029] Next, we will explain the basic cargo-lifting operation of the CSU 1 having the above configuration. In this cargo-lifting operation, the cargo-lifting section 9 and / or the CSU 1 function as a cargo handling device or a cargo-lifting device that carries out bulk cargo M (ship cargo) in the hold 201 of the ship 200 to the outside of the hold 201.

[0030] The operator of the CSU 1 operates the CSU 1 from within the main operation room 16. First, the running unit 2 travels on the rails 3 until it approaches the hatch 21 of the hold 201 to be unloaded. Next, the revolving frame 5 is rotated about a vertical pivot point located at a position overlapping the running unit 2 in top view in FIG. 1 , and the lifting unit 9 at the tip of the boom 7 is moved above the hatch 21 of the hold 201 to be unloaded. To prevent the lifting unit 9 from colliding with the wharf 102 or the ship 200, it is preferable to raise and lower the boom 7 in the forward direction (clockwise in FIG. 1 ) and perform the travel and swing operations with the lifting unit 9 sufficiently raised. Next, the boom 7 is raised and lowered in the reverse direction (counterclockwise in FIG. 1 ), and the scraping unit 11 at the tip of the lifting unit 9 is inserted into the hold 201 through the hatch 21. The movement of the traveling section 2, the rotation of the rotating frame 5, and the raising and lowering of the boom 7 may be performed simultaneously if safety is not an issue.

[0031] After the scraping unit 11 is inserted into the hold 201, the roller chain 25 starts to revolve along the arrow W. As the multiple buckets 27 attached to the roller chain 25 revolve integrally with the roller chain 25, they excavate and scrape off the bulk goods M stored in the hold 201. The bulk goods M scraped off by each bucket 27 are transported upward along the elevator body 14 as the roller chain 25 revolves.

[0032] The scraping unit 11 may change its three-dimensional position within the hold 201 as needed to efficiently scrape bulk material M from various locations within the hold 201. For example, if the surface of the bulk material M becomes lower as the unloading operation progresses, the boom 7 is raised and lowered in the negative direction, lowering the scraping unit 11. Furthermore, to scrape bulk material M near the wall of the hold 201, the position of the scraping unit 11 in the horizontal plane may be changed to approach the wall by operating the traveling unit 2 and / or the rotating frame 5. The scraping unit 11 may change not only its three-dimensional position but also its posture and shape. For example, the scraping unit 11 can rotate around a rotation axis in the extension direction of the elevator body 14, i.e., the vertical direction, and its orientation can be changed as desired. Furthermore, as shown by the dashed line in FIG. 3(B), the scraping unit 11 can also assume an inclined or horizontally elongated shape, contracting vertically and extending horizontally. This allows the scraping section 11 to be brought close to the wall and the bulk cargo M to be scraped off efficiently even in a hold 201 where the horizontal distance from the hatch 21 to the wall is large.

[0033] The control of the CSU state, such as the position, posture, operation, and shape of the scraping unit 11 or the unloading unit 9 within the hold 201, related to the unloading operation of the CSU1 as described above may be performed autonomously by the CSU1 using a photographing device such as a camera or a ranging sensor described below (i.e., the unloading unit 9 and / or CSU1 may be operated automatically), or may be performed manually by an operator in the main control room 16 while communicating with workers within the hold 201.

[0034] After scraping out the bulk goods M from the hold 201 as described above, the bucket 27 rises along the elevator body 14 and turns from an upward to a downward direction as it passes over the drive roller 31a at its top 9a. The bulk goods M that fall as the bucket 27 turns enter a discharge chute and are discharged onto the rotary feeder 37. Thereafter, the bulk goods M are transferred via the boom conveyor 39 and the internal conveyor 43 to a belt conveyor 45 provided on the quay 102 serving as land. By repeatedly performing the above-described carrying-out operation using a plurality of buckets 27, the bulk goods M in the hold 201 are continuously unloaded.

[0035] Next, we will explain the distance measurement sensor provided in the CSU 1 to improve the safety and efficiency of unloading. The distance measurement sensor constitutes a hold detection unit or position measurement unit that detects parts of the hold 201, such as the edge of the opening 21, the top / side surface facing the edge, the ceiling / wall / bottom of the hold 201, and the positions of structures inside the hold 201.

[0036] As shown in FIG. 1 , multiple distance measuring sensors 19 are provided on the upper part of the lifting section 9 to measure the distance to measurement targets below and to the sides. In the illustrated example, the measurement targets of the distance measuring sensors 19 include the edge of the opening 21, the ceiling / wall / bottom of the hold 201, bulk cargo M or other objects, people / structures in the hold 201, a bottom-drilling bulldozer, the scraping section 11, the ship 200, other parts of the CSU 1 such as the boom 7, the rotating frame 5, the running section 2, and the main control room 16, the quay 101, the wharf 102, the rail 3, and the belt conveyor 45. The multiple distance measuring sensors 19 may be disposed, for example, on the upper part of the cylindrical elevator body 14 so as to surround the outer periphery of the elevator body 14. Alternatively, the multiple distance measuring sensors 19 may be provided on a flange 91 that rotatably supports the upper part of the elevator body 14 so as to surround the outer periphery of the elevator body 14. It is preferable that the multiple distance measuring sensors 19 be installed below the connection between the lifting unit 9 and the boom 7 so that the boom 7 does not fall within the measurement range below and to the sides of the multiple distance measuring sensors 19. On the other hand, if the multiple distance measuring sensors 19 are installed above the connection between the lifting unit 9 and the boom 7, each distance measuring sensor 19 should be installed in a position that does not overlap with the boom 7 when viewed from above (when viewed from above in Figure 1). Examples of the arrangement of the multiple distance measuring sensors 19 when viewed from above will be described later. The number of distance measuring sensors 19 is arbitrary. For example, any number of distance measuring sensors 19 that measure distance mainly below the lifting unit 9 and any number of distance measuring sensors 19 that measure distance mainly to the sides of the lifting unit 9 may be installed.

[0037] The scraping unit 11 below the unloading unit 9 is provided with multiple distance measuring sensors 18 for measuring the distance to measurement targets above, to the side, and below. In the illustrated example, the measurement targets of the distance measuring sensors 18 include the edge of the opening 21, the ceiling / wall / bottom of the hold 201, bulk goods M and other objects, people / structures inside the hold 201, a bottom-drilling bulldozer, and other parts of the CSU 1 such as the boom 7. The distance measuring sensors 18 are provided at the front (left side in FIG. 1 ) and rear (right side in FIG. 1 ) of the scraping unit 11, respectively. To avoid deterioration of measurement accuracy due to dust and the like from the bulk goods M scraped by the bucket 27 of the scraping unit 11, the multiple distance measuring sensors 18 are preferably provided at positions (e.g., above the scraping unit 11) away from the location where the bucket 27 excavates the bulk goods M (e.g., below the scraping unit 11). The number of distance measuring sensors 18 is arbitrary. For example, any number of distance measuring sensors 18 that measure distances centered on the sides of the scraping unit 11 and any number of distance measuring sensors 18 that measure distances centered on the bottom of the scraping unit 11 may be provided.

[0038] 4 shows the appearance of distance measuring sensors 18, 19. Distance measuring sensors 18, 19 are, for example, laser sensors capable of distance measurement, and constitute distance measuring units that measure the distance to a measurement object. Distance measuring sensors 18, 19 as laser sensors include a laser emitter (not shown) that serves as an emitter that emits laser light toward a measurement object including the hold 201, and a laser receiver (not shown) that serves as a receiver that receives the laser light reflected by the measurement object. A light-transmitting portion 171 that is an endless band and that allows laser light to pass through is formed around the entire periphery of the side surface of cylindrical housing 17 of distance measuring sensors 18, 19.

[0039] Multiple laser emitters are provided in positions facing the light-transmitting portion 171 inside the housing 17, and emit linear laser light to the outside of the housing 17 through the light-transmitting portion 171. The laser emitters are arranged at predetermined intervals along the direction of the central axis A of the housing 17 (the vertical direction in FIG. 4), but FIG. 4 shows the laser light emitted from a single point for simplicity. As shown in the schematic diagram, the emission angles of the laser emitters differ from each other by approximately 0.1 to 3 degrees. These distance measuring sensors 18 and 19 irradiate laser light within a predetermined angular range above and below the reference plane S, which is a plane perpendicular to the central axis A of the housing 17. (In the illustrated example, the range from θ- to θ+ is used.) While θ- and θ+ can be arbitrarily designed, in the following example, it is assumed that -θ- = θ+ = 15 degrees. In this case, the distance measuring sensors 18 and 19 irradiate laser light within a range of ±15 degrees centered on the reference plane S. Furthermore, these multiple laser emitters can rotate 360 ​​degrees together around the central axis A of the housing 17. Therefore, the distance measuring sensors 18, 19 can irradiate laser light to substantially all measurement targets around (to the sides of) the housing 17. Note that the laser emitters in the distance measuring sensors 18, 19 may be configured to irradiate laser light in any angular range less than 360 degrees around the central axis A of the housing 17 (for example, an angular range of 180 degrees or less or an angular range of 120 degrees or less). Furthermore, it is preferable to use laser light of an invisible wavelength, such as near-infrared light, so as not to disturb people inside or around the CSU 1 or the ship 200.

[0040] Distance measuring sensors 18, 19 rotate multiple laser emitters together and emit pulsed laser light at predetermined rotation angles. The pulsed laser light emitted by each laser emitter is reflected or scattered by the object to be measured, returns to distance measuring sensors 18, 19, and is received by a laser receiver provided together with each laser emitter inside housing 17. A calculation unit (not shown) of distance measuring sensors 18, 19 calculates the distance to the object to be measured based on the time from when the laser emitter emits a pulsed laser light to when the laser receiver receives the pulsed laser light reflected by the object to be measured. This technology is also called LIDAR (Light Detection and Ranging or Laser Imaging Detection and Ranging).

[0041] Although laser sensors have been used above as examples of distance measuring sensors 18 and 19, distance measuring sensors 18 and 19 may also use other types of light or electromagnetic waves. For example, millimeter-wave sensors using so-called millimeter waves with wavelengths of approximately 1 mm to 10 mm may be used as distance measuring sensors 18 and 19. Millimeter waves have a high frequency of approximately 30 GHz to 300 GHz, making them highly directional and allowing them to be treated similarly to lasers. A millimeter-wave sensor may be configured similarly to the laser sensor shown in FIG. 4, except that instead of the laser emitter, a millimeter-wave transmitter (broadly defined emitter) that emits millimeter waves toward the object to be measured is provided, and instead of the laser receiver, a millimeter-wave receiver (broadly defined light receiver) that receives millimeter waves reflected from the object to be measured is provided. Furthermore, optical sensors that use light other than laser light, such as Time of Flight (ToF) image sensors, may also be used as distance measuring sensors 18 and 19. Furthermore, distance measuring sensors 18 and 19 may not have an emitter that emits light or electromagnetic waves toward the object to be measured. For example, the distance measuring sensors 18 and 19 may be a stereo camera or the like that can measure distance by simultaneously photographing an object to be measured from different directions.

[0042] Distance measuring sensors 18, 19 as shown in FIG. 4 are attached to CSU 1 as shown in FIG. 1 in any position and in any orientation depending on the purpose of measurement. For example, distance measuring sensor 18 installed in scraping unit 11 is attached so that center axis A in FIG. 4 is vertical and reference plane S is horizontal. This distance measuring sensor 18 can measure distances within hold 201 with the side of scraping unit 11 as the center. Distance measuring sensor 18 may also be attached so that center axis A in FIG. 4 is horizontal and reference plane S is vertical. This distance measuring sensor 18 can measure distances to opening 21 above scraping unit 11 and bulk cargo M below scraping unit 11. Note that the orientation of center axis A of distance measuring sensor 18 may be any orientation, not limited to vertical or horizontal.

[0043] The distance measurement sensor 19 installed at the top of the unloading section 9 may be mounted so that its central axis A in FIG. 4 is horizontal and its reference plane S is vertical. This distance measurement sensor 19 can measure distances to the edge of the opening 21 of the hold 201 below, bulk cargo M in the hold 201, and the like. Note that this distance measurement sensor 19 can also emit laser light upward, but if there is no measurement target above, the upper side of the distance measurement sensor 19 may be covered with a light-blocking cover, for example, to disable distance measurement above. Furthermore, the distance measurement sensor 19 may be mounted so that its central axis A in FIG. 4 is vertical and its reference plane S is parallel to the horizontal plane. This distance measurement sensor 19 can efficiently measure distances to any measurement target outside the hold 201 to the side. The direction of the central axis A of the distance measurement sensor 19 may be any direction, not limited to horizontal or vertical, but is assumed to be horizontal in the following example.

[0044] By providing distance measuring sensors 18, 19 as described above in the unloading section 9, it is possible to accurately grasp the position of any measurement object, such as the edge of the opening 21, the ceiling / wall / bottom of the hold 201, bulk cargo M or other objects, people / structures inside the hold 201, a bulldozer for raking the bottom, or the scraping section 11. Therefore, it is possible to prevent the unloading section 9 from colliding with other objects during unloading, and the bulk cargo M can be unloaded efficiently.

[0045] FIG. 5 shows an example of the arrangement of distance measurement sensors 19 from a top view. Three distance measurement sensors 191, 192, and 193 are arranged as distance measurement sensors 19, surrounding the outer periphery of flange portion 91 or elevator body 14. Distance measurement sensor 191 is arranged so that its central axis A in FIG. 4 is in the left-right direction in FIG. 5, and a reference plane S1 corresponding to reference plane S in FIG. 4 is in the up-down direction in FIG. 5. Distance measurement sensor 191 measures distance by emitting laser light within a range of ±15 degrees around reference plane S1. Distance measurement sensors 192 and 193 are arranged so that its central axis A in FIG. 4 is in the up-down direction in FIG. 5, and reference planes S2 and S3 corresponding to reference plane S in FIG. 4 are in the left-right direction in FIG. 5. Distance measurement sensors 192 and 193 measure distance by emitting laser light within a range of ±15 degrees around reference planes S2 and S3. The reference planes S2 and S3 of the distance measuring sensors 192 and 193 are different planes parallel to each other and perpendicular to the reference plane S1 of the distance measuring sensor 191.

[0046] The CSU 1 unloads bulk cargo M from the hold 201 with the attitude shown in Figure 5 as the basic attitude for unloading. In this basic attitude, the running unit 2 is positioned away from the front position of the hold 201, and the rotating frame 5 and boom 7 are in a rotating position that forms an acute angle with the rail 3 that forms the track of the running unit 2. In this case, the unloading unit 9 is located above the hold 201 of the ship 200, and the scraping unit 11 at its bottom is inserted into the hold 201 through the opening 21.

[0047] The opening 21 of the hold 201 is often rectangular and elongated in the direction of travel of the ship 200 (the left-right direction in FIG. 5). In this case, the upper edge E11 and the lower edge E12 of the opening 21 can be detected by a distance measurement sensor 191 that emits laser light parallel to the short sides of the opening 21 (the sides in the vertical direction in FIG. 5). Note that the points shown at the centers of the edges E11 and E12 represent the positions where the laser light on the reference plane S1 of the distance measurement sensor 191 hits the edge of the opening 21, and the small rectangle surrounding it schematically represents the range where the laser light, emitted within a range of ±15 degrees from the reference plane S1 as the center, hits the edge of the opening 21. Similar notations are used for the distance measurement sensors 192 and 193.

[0048] Similarly, distance measurement sensors 192 and 193, which emit laser light parallel to the long sides of opening 21 (the left-right sides in FIG. 5), can detect edges E21 and E31 on the left side and edges E22 and E32 on the right side of opening 21. Using two distance measurement sensors 192 and 193 enables highly accurate distance measurement even in the long direction, which is more difficult to measure distances in than the short direction. In this way, the arrangement of distance measurement sensors 191, 192, and 193 in FIG. 5 is suitable for detecting the edges of opening 21 that has a shape that is elongated in one direction, such as a rectangle.

[0049] Furthermore, even if the CSU1 is not in the basic position shown in Figure 5, if the loading section 9 is within the opening 21 when viewed from above, the three ranging sensors 191, 192, and 193 can acquire six ranging point groups on the edge of the opening 21 corresponding to E11, E12, E21, E22, E31, and E32, and the position of the opening 21 can be accurately determined.

[0050] 5 , the basic posture of the CSU 1 during unloading may be such that the travel unit 2 is located in front of the hold 201 and the revolving frame 5 and boom 7 are perpendicular to the rail 3. In this case, the extension direction of the boom 7 coincides with the short side direction of the opening 21, so that the reference plane S1 of the distance measuring sensor 191 is parallel to the extension direction of the boom 7, and the reference planes S2 and S3 of the distance measuring sensors 192 and 193 are perpendicular to the extension direction of the boom 7. If the distance measuring sensors 191, 192, and 193 are rotatable integrally around the axis of the cylindrical elevator body 14, it is possible to easily arrange the distance measuring sensors 191, 192, and 193 appropriately for the elongated opening 21 described above, depending on the change in the basic posture of the CSU 1 during unloading.

[0051] The above-described number and / or arrangement of distance measuring sensors 19 are merely examples, and any number and / or arrangement of distance measuring sensors 19 may be employed. The number of distance measuring sensors 19 is preferably at least two, and more preferably three or more, in order to efficiently measure the position, posture, shape, and other conditions of the hold 201 surrounding the unloading section 9 in a top view. Multiple distance measuring sensors 19 may be arranged at equal intervals along the outer periphery of the flange 91 or the elevator body 14. In this case, the installation orientation of each distance measuring sensor 19 is arbitrary. For example, each distance measuring sensor 19 may be installed so that its reference plane S is in contact with the outer periphery of the flange 91 or the elevator body 14. This symmetrical arrangement allows stable measurement of the position, posture, shape, and other conditions of the hold 201 regardless of the orientation of the CSU 1 during unloading.

[0052] The movable parts of the CSU 1, namely the movable traveling part 2, the swiveling revolving frame 5, the hoistable boom 7, the rotatable and deformable scraping part 11, etc., are controlled according to the distance to the hold 201 itself or to the measurement object inside or outside the hold 201 measured by the distance measuring sensors 18, 19 as described above, thereby preventing the lifting part 9 from colliding with the hold 201 itself or other objects (measurement objects) inside or outside the hold 201 during unloading, and enabling the bulk goods M to be unloaded efficiently. Note that in addition to or instead of the distance measuring sensors 18, 19, an optical sensor such as an image sensor or camera that photographs the measurement object may be used to detect the hold 201 itself or objects inside or outside the hold 201.

[0053] FIG. 6 is a schematic functional block diagram of a calibration device 300 according to this embodiment, which calibrates the distance measurement sensors 18 and 19 installed in a CSU 1 (work machine or cargo handling machine). The calibration device 300 includes a distance measurement point cloud acquisition unit 310, a CSU status acquisition unit 320, a coordinate conversion unit 330, a processing target area setting unit 340, a shape type designation unit 350, a shape feature detection unit 360, an error calculation unit 370, and an installation data correction unit 380. Some of these functional blocks may be omitted as long as the calibration device 300 can achieve at least some of the functions and / or effects described below. These functional blocks may be implemented by the cooperation of hardware resources, such as a central processing unit (CPU), memory, input devices, output devices, and peripheral devices connected to the computer, and software executed using these hardware resources. Regardless of the type or location of the computer, each of the above functional blocks may be implemented by the hardware resources of a single computer or by combining hardware resources distributed across multiple computers.

[0054] The calibration device 300 corrects or calibrates the installation data α of one or more distance measurement sensors 18, 19 installed in the CSU 1. Here, the installation data α of each distance measurement sensor 18, 19 represents the position and / or orientation of the distance measurement sensor 18, 19 installed in the CSU 1. Specifically, the installation data α of each distance measurement sensor 18, 19 may represent the three-dimensional position of the distance measurement sensor 18, 19 in the CSU 1 as shown in FIG. 1 or FIG. 5. Furthermore, the installation data α of each distance measurement sensor 18, 19 may represent the three-dimensional orientation of the distance measurement sensor 18, 19 with respect to the CSU 1 (for example, the direction of the central axis A shown in FIG. 4) as shown in FIG. 4 or FIG. 5.

[0055] Such installation data α of each of the distance measuring sensors 18, 19 is stored in advance as design data of the distance measuring sensors 18, 19, or as recorded data when the distance measuring sensors 18, 19 are actually installed in the CSU 1. However, since the pre-stored installation data α may deviate from the actual three-dimensional position and / or three-dimensional orientation of the distance measuring sensors 18, 19, calibration by the calibration device 300, i.e., correction of the installation data α of each of the distance measuring sensors 18, 19, is required.

[0056] To calibrate each of the distance measuring sensors 18, 19, the calibration device 300 causes each of the distance measuring sensors 18, 19 to measure a measurement object. Here, the measurement object may be an object whose position, orientation, shape, etc. are known (e.g., the rail 3 shown in Figures 1, 2, 5, etc.). However, the calibration device 300 according to this embodiment can also use an object whose shape, etc. is unknown as the measurement object, as long as its position and orientation are substantially unchanged. In the following example, a belt conveyor 45 whose position, orientation, shape, etc. are unknown is used as the measurement object for calibrating each of the distance measuring sensors 18, 19. However, the measurement object in this embodiment is arbitrary and may be, for example, a quay wall 101, a wharf 102, a rail 3, etc.

[0057] Before describing each functional block of the calibration device 300, the coordinate system underlying it will be explained. Fig. 7 schematically shows various coordinate systems that can be set for the CSU 1. Fig. 7(A) is a schematic diagram of the CSU 1 in a vertical plane including the traveling unit 2, revolving frame 5, boom 7, and hoisting unit 9, and Fig. 7(B) is a schematic diagram of the CSU 1 as seen from above or in a plan view. Fig. 7(A) is a cross-sectional view taken along a plane including the boom 7 extending diagonally downward and to the left from the revolving frame 5 in Fig. 7(B).

[0058] The coordinate system u is a ground coordinate system based on the ground on which the traveling unit 2 travels (or a moving unit coordinate system based on the traveling unit 2), and u is the x-axis in the xyz Cartesian coordinate system. x axis, and u as the y-axis y axis, and u as the z axis zFor example, the origin of the ground coordinate system u is set on the track of the traveling part 2 formed by the rail 3, and u x The direction of the axis coincides with the laying direction of the rail 3, which is the direction of movement of the running part 2, and u y The axis is oriented in the horizontal plane as u x The direction is perpendicular to the axis, and z The axis is oriented vertically.

[0059] Here, "the coordinate system u is a ground coordinate system based on the ground" means that the coordinate system u has an origin at any point on the ground. For example, the ground coordinate system u may be a coordinate system that has an origin at any position on the wharf 102, which is the land on which the traveling unit 2 is installed, or a coordinate system that has an origin at the traveling unit 2 itself traveling on the ground (a moving unit coordinate system based on the traveling unit 2). In the illustrated example, in the ground coordinate system u, the traveling unit 2 is positioned in a fixed posture and moves in the direction of u. x Since it moves only along the axis, the u y coordinates and u z The coordinates do not change (in the following, for the sake of simplicity, the coordinates of the runner 2 are assumed to be u y coordinates and u z (The coordinate is assumed to be 0.) x The coordinates are the position x of the running part 2 on the rail 3. tl In this way, the three-dimensional coordinates of the traveling unit 2 in the ground coordinate system u are (u x ,u y ,u z )=(x tl ,0,0). In the illustrated example, for simplicity, x The direction of the axes coincides with the direction in which the rails 3 are laid, but the direction of each axis of the ground coordinate system u can be set arbitrarily.

[0060] The coordinate system r is a rotation unit coordinate system based on the rotation frame 5, and r is the x-axis in the xyz Cartesian coordinate system. x axis and r as the y-axis y axis, and r as the z axis z The origin of the rotating unit coordinate system r is the rotation center O of the rotating frame 5 in the top view of FIG.r In the cross-sectional view of Figure 7(A), the center of rotation O r It coincides with the point on land directly below. x The axis direction is u x It rotates by a rotation angle θ2 relative to the axis direction, and r y The axis is oriented in the horizontal plane as r x r is a direction perpendicular to the axis (the extension direction of the boom 7 in FIG. 7(B) as viewed from above), z The axis is oriented vertically.

[0061] In the example shown, the center of rotation O r coincides with the origin of the coordinate system r, so that r x coordinates and r y The coordinate is 0. Also, the center of rotation O r r z The coordinate is the height h from the land r The rotation angle θ2, which indicates the posture of the rotating frame 5, can be measured by an angle sensor or the like. r The three-dimensional coordinates of (r x ,r y ,r z )=(0,0,h r ) The rotating unit coordinate system r may be a coordinate system with the origin at any position on the rotating frame 5, boom 7, counterweight 13, or main operation room 16 that can rotate integrally with the rotating unit. In the illustrated example, for the sake of simplicity, r y The direction of the axis coincides with the extension direction of the boom 7 when viewed from above, but the direction of each axis of the rotation unit coordinate system r can be set arbitrarily.

[0062] The coordinate system b is a coordinate system of the hoisting section based on the boom 7 and the lifting section 9, and b is the x-axis in the xyz Cartesian coordinate system. x axis, and b as the y-axis y axis, and b as the z axis z The origin of the coordinate system b of the hoisting unit is set, for example, at the connection part between the boom 7 and the lifting unit 9. yThe direction of the axis is horizontal and coincides with the extension direction of the boom 7 in FIG. 7(B) as viewed from above, and b x The axis direction is b in the horizontal plane. y The direction is perpendicular to the axis, and b z The axis is oriented vertically.

[0063] In the illustrated example, the boom 7 is located at the base end side of the center of elevation O b As shown in Figure 7(A), the origin of the coordinate system b and the center of the undulations O b The distance between b1 Then, the center of the undulations in the coordinate system b is O b coordinates (b x ,b y ,b z ) is (0,-L b1 cosθ1,-L b1 sin θ1). Here, the hoisting angle θ1, which indicates the posture of the hoisting unit, can be measured by an angle sensor or the like. The origin of the hoisting unit coordinate system b can be any point on the boom 7 that constitutes the hoisting unit, for example, the hoisting center O b may be the origin of the coordinate system b of the undulating part. In this case, the directions of the axes remain as shown in the figure, and the coordinates (b x ,b y ,b z ) is (0,L b1 cosθ1,L b1 sinθ1). In the example shown, for simplicity of explanation, y The direction of the axis coincides with the extension direction of the boom 7 when viewed from above, but the direction of each axis of the undulating portion coordinate system b can be set arbitrarily.

[0064] The coordinate system l is a distance measurement unit coordinate system based on each distance measurement sensor 19, and l is the x-axis in the xyz Cartesian coordinate system. x axis and l as the y-axis y axis, and l as the z axis z The origin of the distance measurement unit coordinate system l is set, for example, at the mounting position of each distance measurement sensor 19 on the CSU 1 or the loading unit 9. yThe direction of the axis is horizontal and coincides with the extension direction of the boom 7 in the top view of FIG. 7(B), and x The axis direction is in the horizontal plane. y The direction is perpendicular to the axis, and z The axis direction is the vertical direction. When a plurality of distance measurement sensors 19 are provided, such as distance measurement sensors 191 to 193 in Fig. 5, the distance measurement unit coordinate system 1 may be set individually for each distance measurement sensor 19.

[0065] In an example where the installation position of each distance measuring sensor 19 coincides with the origin of the distance measuring unit coordinate system l, the three-dimensional coordinates (l x ,l y ,l z ) is always (0,0,0). Also, the orientation of the distance measurement unit coordinate system l (l x axis, l y axis, l z The direction of the axis) represents the attitude of each distance measuring sensor 19. The distance measuring unit coordinate system l may have an origin at any position on the unloading unit 9 where each distance measuring sensor 19 is attached. In the illustrated example, for the sake of simplicity, the distance measuring unit coordinate system l is y The direction of the axis coincides with the extension direction of the boom 7 when viewed from above, but the direction of each axis of the distance measuring unit coordinate system l can be set arbitrarily.

[0066] The coordinate system d is a distance measurement unit coordinate system based on each distance measurement sensor 18, and d is the x-axis in the xyz Cartesian coordinate system. x axis, and d as the y-axis y axis, and d as the z axis z The origin of the distance measuring unit coordinate system d is, for example, provided at the connecting portion between the elevator body 14 and the scraping unit 11. y The direction of the axis is horizontal and coincides with the extension direction of the scraping part 11 (not shown) in the top view of FIG. 7(B), and d x The axis direction is d in the horizontal plane. y The direction is perpendicular to the axis, and d z The axis is in the vertical direction. As shown in Figure 7(B), d y The axis direction is b y axis and r yThe direction of the axis, i.e., the extension direction of the boom 7 in a top view, is shifted by a rotation angle θ4. This means that the scraping unit 11 rotates by θ4 around the axis of the elevator body 14. When multiple distance measuring sensors 18 are provided, the distance measuring unit coordinate system d may be common to the multiple distance measuring sensors 18, or the distance measuring unit coordinate system d may be set individually for each distance measuring sensor 18.

[0067] The origin of the distance measurement unit coordinate system d may be set at the attachment position of each distance measurement sensor 18 to the CSU 1 or the unloading unit 9. In this case, the three-dimensional coordinates (d x ,d y ,d z ) is always (0,0,0). Also, the orientation of the distance measurement unit coordinate system d (d x axis, d y axis, d z The direction of the axis) represents the attitude of each distance measuring sensor 18. In the illustrated example, for the sake of simplicity, z The direction of the axes coincides with the vertical direction, but the direction of each axis of the distance measuring unit coordinate system d can be set arbitrarily.

[0068] In FIG. 7(A), the scraping unit 11 is schematically shown as a rectangle extending in a direction perpendicular to the axial direction of the elevator body 14. However, as schematically shown in FIG. 7(C), the scraping unit 11 may be configured with a main part 11A that scrapes off bulk goods M and a bending part 11B that can be bent relative to the elevator body 14. Even in such a case, the origin of the distance measurement unit coordinate system d can be set at any position on the scraping unit 11, i.e., on the main part 11A or the bending part 11B. In the coordinate transformation by the coordinate transformation unit 330 described below, the bending angle θ5 of the bending part 11B is also taken into account.

[0069] The coordinate conversion unit 330, described later, converts the ranging point cloud in the ranging unit coordinate system d acquired by the ranging sensor 18 and / or the ranging point cloud in the ranging unit coordinate system l acquired by the ranging sensor 19 into coordinates in a reference coordinate system for the CSU1. In the following description, unless otherwise specified, the "ranging unit coordinate system" refers to at least one of the ranging unit coordinate system d and the ranging unit coordinate system l. The reference coordinate system for the CSU1 may be the ground coordinate system u, the rotation unit coordinate system r, or the relief unit coordinate system b, or any coordinate system set from the viewpoint of the CSU1, in other words, any coordinate system in which the CSU1 recognizes or tracks the position and orientation of the origin (the direction of each axis). The CSU1 can handle ranging point clouds acquired by multiple ranging sensors 18 and 19 in different ranging unit coordinate systems d and l in a unified manner in such a reference coordinate system (regardless of the positions and orientations of the ranging sensors 18 and 19).

[0070] Next, each functional block of the calibration device 300 in FIG. 6 will be described.

[0071] The ranging point cloud acquisition unit 310 acquires ranging point clouds on an arbitrary or unknown measurement object, such as a belt conveyor 45, in a ranging unit coordinate system d, l based on the ranging sensors 18, 19, using ranging sensors 18, 19 installed on the CSU 1 as a work machine or cargo handling machine. In the example of this embodiment, for calibration by the calibration device 300, the ranging point cloud acquisition unit 310 acquires ranging point clouds on the surface of the measurement object, such as the belt conveyor 45.

[0072] The ranging point cloud acquisition unit 310 acquires ranging point clouds on the measurement object (such as the belt conveyor 45) while changing at least one of the positions and attitudes of the ranging sensors 18, 19 relative to the measurement object using the CSU 1. Specifically, the CSU 1 acquires ranging point clouds on the measurement object using the ranging point cloud acquisition unit 310 while changing the relative positions and / or attitudes of the ranging sensors 18, 19 or the lifting unit 9 relative to the measurement object by changing parameters (CSU state) related to the positions, attitudes, operations, etc. of the traveling unit 2, the revolving frame 5, the boom 7, the lifting unit 9, etc., which are movable units.

[0073] The CSU state when the ranging point cloud acquisition unit 310 acquires each ranging point cloud is acquired by the CSU state acquisition unit 320. The ranging point cloud acquired by the ranging point cloud acquisition unit 310 and the CSU state acquired by the CSU state acquisition unit 320 are associated with each other based on common time information, etc. The CSU state acquired by the CSU state acquisition unit 320 includes the position x of the traveling unit 2 on the rail 3, as described above with reference to FIG. tl , the rotation angle θ2 of the rotating frame 5, the elevation angle θ1 of the boom 7, the rotation angle θ4 of the lifting unit 9 or scraping unit 11, and the bending angle θ5 of the bending unit 11B are exemplified.

[0074] The coordinate conversion unit 330 converts the ranging point cloud in the ranging unit coordinate system acquired by the ranging point cloud acquisition unit 310 from one or more ranging sensors 18, 19 into coordinates in a reference coordinate system (e.g., the ground coordinate system u) related to the CSU 1. Such coordinate conversion between the ranging unit coordinate system and the reference coordinate system can be performed based on the above-mentioned installation data α representing the three-dimensional position and / or three-dimensional attitude of each ranging sensor 18, 19 relative to the CSU 1 or the unloading unit 9, and the CSU state at each time acquired by the CSU state acquisition unit 320. For example, if different ranging unit coordinate systems are set for the multiple ranging sensors 18, 19, the ranging point clouds acquired by the ranging point cloud acquisition unit 310 are expressed in different ranging unit coordinate systems. However, through the coordinate conversion by the coordinate conversion unit 330, the ranging point clouds acquired by the different ranging sensors 18, 19 and / or different ranging unit coordinate systems are uniformly expressed in a reference coordinate system common to the CSU 1.

[0075] The ranging point cloud converted into the reference coordinate system by the coordinate conversion unit 330 may be displayed on an operation screen of a computer CP used by a user such as an administrator of the CSU1 and / or the calibration device 300. Fig. 8 shows an example of an operation screen 400 of such a computer CP.

[0076] The ranging point cloud display area 410 displays a ranging point cloud 331, which has been converted into a reference coordinate system (the XYZ coordinate system in FIG. 8) by the coordinate conversion unit 330, in three dimensions. Each ranging point (unidentifiable in FIG. 8) constituting the ranging point cloud 331 is a point in the XYZ coordinate system, which is the reference coordinate system. In the illustrated example, the ranging point cloud 331 is distributed on the ground B of the wharf 102 on which the belt conveyor 45, which is the measurement object, is installed, the side wall surface W or vertical surface, edge E of the belt conveyor 45, and the top surface U or horizontal surface of the belt conveyor 45. These ranging point clouds 331 are typically acquired from multiple ranging sensors 18, 19, but may also be acquired from a single ranging sensor 18, 19.

[0077] In the data import area 420, in response to a pressing operation or selection operation by the user of the computer CP, a ranging point cloud import button 421 (displayed as "LiDAR") that imports the ranging point cloud acquired by the ranging point cloud acquisition unit 310, and a CSU status import button 422 (displayed as "CSU status") that imports the CSU status acquired by the CSU status acquisition unit 320 are displayed. The ranging point cloud 331 displayed in the ranging point cloud display area 410 described above is the ranging point cloud imported by the ranging point cloud import button 421, converted into a reference coordinate system (XYZ coordinate system) by the coordinate conversion unit 330 based on the CSU status imported by the CSU status import button 422 and installation data α that is not explicitly displayed on the operation screen 400.

[0078] 6 sets a processing target area in the ranging point cloud 331 that has been coordinate-converted by the coordinate conversion unit 330. The processing target area is a three-dimensional area (space) in a reference coordinate system (the XYZ coordinate system in FIG. 8) that is the target of processing by all or some of the shape type designation unit 350, geometric feature detection unit 360, error calculation unit 370, and installation data correction unit 380 that are downstream of the processing target area designation unit 340. As will be described later, preferably all of the shape type designation unit 350, geometric feature detection unit 360, error calculation unit 370, and installation data correction unit 380 perform their respective processes on the ranging point cloud (part of the ranging point cloud 331) included in the processing target area set by the processing target area designation unit 340.

[0079] 8 illustrates a first processing target region R1 targeting the edge E of the belt conveyor 45 as the measurement target, a second processing target region R2 targeting the side wall surface W of the belt conveyor 45, and a third processing target region R3 targeting the top surface U of the belt conveyor 45. The first processing target region R1 is a rectangular parallelepiped region surrounding a three-dimensional space that is likely to correspond to the edge E of the belt conveyor 45 in the three-dimensional distribution of the ranging point cloud 331 displayed in the ranging point cloud display area 410. The second processing target region R2 is a rectangular parallelepiped region surrounding a three-dimensional space that is likely to correspond to the side wall surface W of the belt conveyor 45 in the three-dimensional distribution of the ranging point cloud 331 displayed in the ranging point cloud display area 410. The third processing target region R3 is a rectangular parallelepiped region surrounding a three-dimensional space that is likely to correspond to the top surface U of the belt conveyor 45 in the three-dimensional distribution of the ranging point cloud 331 displayed in the ranging point cloud display area 410.

[0080] In this manner, the processing target area setting unit 340 sets three-dimensional spaces that are likely to include geometric features such as the edge E, side wall surface W, and top surface U of the belt conveyor 45 as the measurement object as processing target areas R1 to R3, etc. In the illustrated example, all of the processing target areas R1 to R3 are rectangular parallelepiped regions, but processing target areas according to the present disclosure may have any other shape. Furthermore, in this embodiment, because the belt conveyor 45 as the measurement object is unknown to the calibration device 300, it is difficult to accurately detect geometric features such as the edge E, side wall surface W, and top surface U during processing by the processing target area setting unit 340. Detection of these geometric features must wait until the geometric feature detection unit 360, which is performed later. Therefore, it is preferable that the processing target area setting unit 340 set relatively large processing target areas R1 to R3 that include as many distance measurement points as possible around the edge E, side wall surface W, and top surface U of the belt conveyor 45.

[0081] The processing target area setting unit 340 may set the processing target areas R1 to R3 in response to an operation by the user of the computer CP. In the operation screen 400 of Fig. 8, an addition button 431 (displayed as "Add") for adding a new processing target area and a deletion button 432 (displayed as "Delete") for deleting an existing processing target area are displayed in a processing target area setting area 430 in response to a pressing operation or a selection operation by the user of the computer CP. A processing target area list area 433 displays a list of processing target areas to be set.

[0082] The processing target area detail setting area 440 displays detailed information about one processing target area selected by the user of the computer CP in the processing target area list area 433. This detailed information can be edited by the user of the computer CP. In the example of this embodiment in which the processing target areas R1 to R3 are rectangular parallelepiped areas, the editable detailed information displayed includes a size 441 of the processing target area (displayed as "Size", e.g., dimensions in the X-axis, Y-axis, and Z-axis directions), a position 442 of the processing target area (displayed as "Pos.", e.g., XYZ coordinates of the center of gravity or center), and an attitude 443 of the processing target area (e.g., roll angle displayed as "Roll", pitch angle displayed as "Pitch", yaw angle displayed as "Yaw").

[0083] The shape type 444 or attribute (displayed as "Attribute") displayed in the processing target area detail setting area 440 is the type of geometric feature of the belt conveyor 45 as the measurement object to be detected by the geometric feature detection unit 360, which is specified for each processing target area by the shape type specification unit 350 in FIG. 6. Here, examples of the type of geometric feature of the belt conveyor 45 include flat surfaces such as the side wall surface W and the top surface U on the belt conveyor 45, and linear edges E. For example, for processing target areas R2 and R3 that target flat surfaces such as the side wall surface W and the top surface U, the shape type specification unit 350 specifies the shape type 444 of "Plane." Furthermore, for processing target area R1 that targets the linear edges E, the shape type specification unit 350 specifies the shape type 444 of "Line."

[0084] The processing by the processing target area setting unit 340 and / or the shape type designation unit 350 as described above may be performed in response to manual operation by a user of the computer CP, or all or part of the processing may be performed automatically by a processor (not shown) of the computer CP or the calibration device 300. In the latter case, the processor of the calibration device 300 analyzes the distribution of the ranging point cloud 331 in the reference coordinate system and automatically sets a processing target area (three-dimensional space) that can effectively detect shape features of the belt conveyor 45, such as the edge E, side wall surface W, and top surface U. The processing target area that is automatically set in this manner may be displayed on the operation screen 400 in FIG. 8, and the user of the computer CP may edit the detailed information displayed in the processing target area detail setting area 440 as necessary.

[0085] The preview area 450 displays a selection display button 451 (displayed as "Display") that selectively displays in the ranging point cloud display area 410 only the ranging point cloud contained in one processing target area (rectangular area) selected in the processing target area list area 433 in response to a pressing or selection operation by the user of the computer CP, and a cancel button 452 (displayed as "Cancel") that cancels the selection display (preview).

[0086] The geometric feature detection unit 360 detects geometric features of the belt conveyor 45 as the measurement object based on the distance measurement point cloud 331 in the reference coordinate system that has undergone coordinate transformation by the coordinate transformation unit 330. The geometric feature detection unit 360 may detect one or more geometric features of the belt conveyor 45 based on the entire distance measurement point cloud 331 as schematically shown in Fig. 8. However, in order to improve the detection accuracy of each geometric feature of the belt conveyor 45, it is preferable that the geometric feature detection unit 360 detects each geometric feature of each shape type (e.g., plane or straight line) specified by the shape type specification unit 350 based on each distance measurement point cloud included in each of the processing target regions R1 to R3 set by the processing target region setting unit 340.

[0087] Specifically, the geometric feature detection unit 360 detects an edge E, which is a geometric feature of the "straight line" shape type specified by the shape type designation unit 350, based on the ranging points included in the processing target region R1 set by the processing target region setting unit 340. The geometric feature detection unit 360 also detects a side wall surface W, which is a geometric feature of the "flat surface" shape type specified by the shape type designation unit 350, based on the ranging points included in the processing target region R2 set by the processing target region setting unit 340. The geometric feature detection unit 360 also detects a top surface U, which is a geometric feature of the "flat surface" shape type specified by the shape type designation unit 350, based on the ranging points included in the processing target region R3 set by the processing target region setting unit 340.

[0088] The geometric feature detection unit 360 can detect straight lines such as an edge E based on the distance measurement points in the processing target area R1 using a known line detection algorithm. The geometric feature detection unit 360 can also detect flat surfaces such as a side wall surface W and an upper surface U based on the distance measurement points in the processing target areas R2 and R3 using a known plane detection algorithm. The geometric feature detection unit 360 outputs parameters that represent the detected straight lines such as an edge E and / or flat surfaces such as a side wall surface W and an upper surface U in a reference coordinate system (XYZ coordinate system), which is a three-dimensional space. These parameters that specify each geometric feature or each geometric feature itself will be collectively referred to as geometric feature parameters β or geometric features β below.

[0089] The error calculation unit 370 calculates the error or distance between each geometric feature β detected by the geometric feature detection unit 360 and each ranging point included in the ranging point group used for the detection, and performs statistical processing such as averaging as necessary. Specifically, the error calculation unit 370 calculates the error or distance from the straight line representing the edge E for each ranging point included in the processing target region R1. The error calculation unit 370 also calculates the error or distance from the plane representing the side wall surface W for each ranging point included in the processing target region R2. Furthermore, the error calculation unit 370 calculates the error or distance from the plane representing the top surface U for each ranging point included in the processing target region R3.

[0090] The installation data correction unit 380 corrects the installation data α of one or more distance measurement sensors 18, 19 so as to reduce the error between the geometric feature β calculated by the error calculation unit 370 and the distance measurement point cloud 331. Here, the installation data correction unit 380 preferably corrects one or more geometric feature parameters β obtained by the geometric feature detection unit 360, in addition to the installation data α of the one or more distance measurement sensors 18, 19. In this case, the installation data correction unit 380 varies the installation data α and the geometric feature parameter β, and outputs an optimal set of installation data α and geometric feature parameter β that minimizes the error calculated by the error calculation unit 370.

[0091] As described above, the installation data correction unit 380 optimizes the set of installation data α and geometric feature parameter β so as to minimize the error (error or deviation between the geometric feature β and the ranging point cloud) calculated by the error calculation unit 370 as a cost function. As a method for such optimization, the well-known Levenberg-Marquardt algorithm may be used.

[0092] The processing by the shape feature detection unit 360, the error calculation unit 370, and the installation data correction unit 380 as described above may be executed all at once by the user of the computer CP pressing or selecting the execute button 461 (displayed as "Execute") displayed in the calibration area 460 on the operation screen 400 of FIG. 8.

[0093] The cancel button 462 (displayed as "Cancel") in the calibration area 460 is a button for canceling the calibration executed by the execute button 461. The save button 463 (displayed as "Save") in the calibration area 460 is a button for saving the results of the calibration executed by the execute button 461. The discard button 464 (displayed as "Abandon") in the calibration area 460 is a button for discarding the results of the calibration executed by the execute button 461.

[0094] The results of the calibration performed by the execute button 461 (for example, the optimized installation data α of the multiple distance measuring sensors 18 and 19 and information on multiple geometric characteristic parameters β) may be displayed in a message area 470.

[0095] According to the present embodiment described above, the installation data α of one or more distance measuring sensors 18, 19 can be effectively corrected or calibrated by utilizing the shape feature β detected based on the distance measuring point group 331 on the object to be measured, such as a belt conveyor 45, whose shape, etc., is unknown.

[0096] 9 is a flowchart showing an example of the calibration of one or more distance measuring sensors 18, 19 by the calibration device 300 according to this embodiment. In the explanation of the flowchart, "S" denotes a step or process.

[0097] In S1, the ranging point cloud acquisition unit 310 acquires a ranging point cloud on an arbitrary or unknown measurement object, such as a belt conveyor 45, in a ranging unit coordinate system d, l based on the ranging sensors 18, 19, using the ranging sensors 18, 19 installed on the CSU1, which serves as a work machine or a cargo handling machine. In S2, the CSU status acquisition unit 320 acquires the CSU status when the ranging point cloud was acquired in S1. As described above, the processes of S1 and S2 may be repeated while the CSU1 changes at least one of the position and orientation of the ranging sensors 18, 19 relative to the measurement object (such as the belt conveyor 45).

[0098] In S3, the coordinate conversion unit 330 converts the ranging point cloud in the ranging unit coordinate system acquired in S1 from one or more ranging sensors 18, 19 into coordinates in the reference coordinate system for CSU1 based on the installation data α of each ranging sensor 18, 19 and the CSU state acquired in S2. As will be described later, S3 can be repeated for different installation data α, but in the first S3, it is preferable to use, as the installation data α for the coordinate conversion, pre-stored design data for each ranging sensor 18, 19 or recorded data when each ranging sensor 18, 19 is actually installed on CSU1.

[0099] In S4, the processing target area setting unit 340 sets preferably a plurality of processing target areas in the ranging point cloud 331 that has been coordinate-transformed in S3. In S5, the shape type designation unit 350 designates, for each processing target area set in S4, the type of shape feature of the belt conveyor 45 as the measurement object to be detected in the subsequent S7. In S6, it is determined whether the setting of all processing target areas has been completed. If the determination in S6 is "No," the process returns to S4, and a new processing target area is set. If the determination in S6 is "Yes," the process proceeds to S7.

[0100] In S7, the geometric feature detection unit 360 detects geometric features of each geometric type specified in S5 based on the ranging point groups included in each processing target area set in S4. Note that the processing from S7 onwards may be performed on ranging point groups 331 of multiple frames acquired at different times or different time periods. Here, the number of ranging points included in each processing target area may vary significantly depending on the time or time period, so the accuracy and robustness of the calibration can be improved by processing only frames or processing target areas that include a predetermined number of ranging points or more in S7 onwards.

[0101] In S8, the error calculation unit 370 calculates the error or distance between each geometric feature β detected in each frame and / or each processing target area in S7 and each ranging point included in the ranging point group used for that detection. In S9, it is determined whether processing has been completed for all processing target areas or frames. If the determination in S9 is "No," the process returns to S7, and geometric features are detected in unprocessed processing target areas or frames. If the determination in S9 is "Yes," the process proceeds to S10.

[0102] In S10, the installation data correction unit 380 optimizes or corrects the installation data α of one or more distance measurement sensors 18, 19 and one or more geometric feature parameters β obtained in S7 so as to reduce the error between the geometric feature β calculated in S8 and the ranging point cloud 331. The optimization of the geometric feature parameter β here may include performing a geometric feature detection process similar to that in S7 but based on different parameters or algorithms.

[0103] In S11, it is determined whether the error (calculated in S8) for the geometric feature parameter β optimized in S10 is within the allowable range. If the determination in S11 is "No," the process returns to S3, and the coordinate transformation of the ranging point cloud in the ranging unit coordinate system acquired in S1 is redone using the installation data α of one or more ranging sensors 18, 19 optimized in S10. Because the updated or optimized installation data α is used, the ranging point cloud 331 obtained in the second or subsequent S3 iterations will be more accurate than the ranging point cloud 331 obtained in the previous or previous S3 iterations. In this way, by repeating S3 to S11 (however, S4 to S6, which do not change significantly from one iteration to the next, may be omitted or simplified), the installation data α of the multiple ranging sensors 18, 19 is preferably gradually optimized or calibrated. If the determination in S11 is "Yes," the calibration by the calibration device 300 is completed.

[0104] The present disclosure has been described above based on the embodiments. Various modifications are possible to the combinations of the components and processes in the exemplary embodiments, and it will be obvious to those skilled in the art that such modifications are included within the scope of the present disclosure.

[0105] The present disclosure is not limited to the bucket elevator type continuous unloader described in relation to the embodiment, but can also be applied to spiral type unloaders and unloaders equipped with air conveying mechanisms.

[0106] In the embodiment, the CSU1 is exemplified as a work machine or a cargo handling machine, but the present disclosure can be applied to any other work machine. Examples of work machines include construction machines such as excavators and cranes, and cargo handling machines such as forklifts, including AGFs (Automated Guided Forklifts).

[0107] The configuration, operation, and function of each device and method described in the embodiments can be realized by hardware resources, software resources, or a combination of hardware and software resources. Examples of hardware resources include processors, ROMs, RAMs, and various integrated circuits. Examples of software resources include operating systems, applications, and other programs. [Explanation of symbols]

[0108] 1 Cargo unloading unit (CSU), 9 Unloading unit, 11 Scraping unit, 18 Distance measurement sensor, 19 Distance measurement sensor, 21 Opening, 201 Hold, 300 Calibration device, 310 Distance measurement point cloud acquisition unit, 320 CSU status acquisition unit, 330 Coordinate conversion unit, 331 Distance measurement point cloud, 340 Processing target area setting unit, 350 Shape type designation unit, 360 Shape feature detection unit, 370 Error calculation unit, 380 Installation data correction unit, 400 Operation screen, R1 to R3 Processing target area.

Claims

1. a distance measurement point cloud acquisition unit that acquires a distance measurement point cloud on a measurement object using a distance measurement sensor installed on the work machine; a coordinate conversion unit that converts the range measurement point cloud into coordinates in a reference coordinate system related to the work machine based on installation data of the range measurement sensor; a shape feature detection unit that detects shape features of the measurement object based on the distance measurement point group in the reference coordinate system; an installation data correction unit that corrects the installation data so as to reduce an error between the shape features and the range-finding point cloud; A calibration device comprising:

2. the distance measurement point cloud acquisition unit acquires the distance measurement point cloud on the measurement object using a plurality of distance measurement sensors installed on the work machine; the coordinate conversion unit converts the range finding point cloud into coordinates in the reference coordinate system based on installation data of each of the range finding sensors; the installation data correction unit corrects the installation data of the plurality of distance measurement sensors so as to reduce an error between the shape features and the distance measurement point cloud; The calibration device according to claim 1 .

3. The calibration device according to claim 1 or 2, wherein the distance measurement point cloud acquisition unit acquires the distance measurement point cloud while changing at least one of the position and orientation of the distance measurement sensor relative to the measurement object by the work machine.

4. a processing target area setting unit that sets a processing target area in the range-finding point cloud; at least one of the shape feature detection unit and the installation data correction unit performs the processing on the ranging point cloud included in the processing target area; 3. The calibration device according to claim 1.

5. 5. The calibration device according to claim 4, further comprising a shape type designation unit that designates a type of shape feature that the shape feature detection unit should detect for the processing target region.

6. The calibration device according to claim 1 , wherein the geometric feature is at least one of a flat surface and a linear edge on the measurement object.

7. The calibration device according to claim 1 or 2, wherein the installation data represents a position and an attitude of the distance measuring sensor when the distance measuring sensor is installed on the work machine.

8. 3. The calibration device according to claim 1, wherein the work machine is a cargo handling machine that handles cargo.

9. acquiring a range measurement point cloud on the measurement object by a range measurement sensor installed on the work machine; converting the range measurement point cloud into coordinates in a reference coordinate system related to the work machine based on installation data of the range measurement sensor; Detecting shape features of the measurement object based on the range-finding point group in the reference coordinate system; correcting the installation data so that an error between the shape features and the range-finding point cloud is reduced; A calibration method to perform.

10. acquiring a range measurement point cloud on the measurement object by a range measurement sensor installed on the work machine; converting the range measurement point cloud into coordinates in a reference coordinate system related to the work machine based on installation data of the range measurement sensor; Detecting shape features of the measurement object based on the range-finding point group in the reference coordinate system; correcting the installation data so that an error between the shape features and the range-finding point cloud is reduced; A storage medium storing a calibration program that causes a computer to execute the above.

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