Map generation device, work machine, and map generation method

Abstract

The objective is to easily and accurately generate 3D map data of the ground surrounding a work machine. [Solution] The map generation device comprises a distance sensor 200 attached to a work machine so that its measurement axis intersects the ground, and a map generation unit that generates three-dimensional map data by converting the point cloud data acquired by the distance sensor 200 from a measurement coordinate system (X'Y'Z' coordinate system) in which the coordinate axis coaxial with the measurement axis of the distance sensor 200 is the height axis, to a map coordinate system (XYZ coordinate system) in which the coordinate axis extending vertically in real space is the height axis. Before executing the map generation process, the map generation unit causes the distance sensor 200 to acquire point cloud data, calculates the height axis Z' of the measurement coordinate system and the height axis Z of the map coordinate system and the angular displacement θ based on the point cloud data, and when executing the map generation process, converts the point cloud data acquired by the distance sensor 200 to the map coordinate system by rotating it by the angular displacement θ around the origin of the measurement coordinate system.

Description

Technical Field

[0001] The present invention relates to a map generation device, a work machine, and a map generation method.

Background Art

[0002] Conventionally, a map generation device that generates three-dimensional map data including information such as the uneven shape and inclination direction of the ground is known.

[0003] Patent Document 1 discloses a map generation device and a control device for a crane that uses map data generated by the map generation device. The map generation device generates three-dimensional map data of a work site based on point cloud data acquired by a distance sensor such as a laser scanner (see paragraph

[0029] of Patent Document 1). The control device is configured to automatically adjust the amount of extension and contraction of the crane's jack based on the map data of the work site generated by the map generation device.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the map generation device shown in Patent Document 1, it is necessary to scan the ground of the work site in advance with a distance sensor to generate three-dimensional map data before installing the crane (work machine), and there is a problem of poor convenience.

[0006] Therefore, one might consider improving convenience by pre-installing distance sensors on the work machine. However, in this case, when installing the distance sensor, there is a risk that the measurement axis of the distance sensor may be tilted in the vertical direction due to dimensional tolerances of the distance sensor itself or the mounting parts. If the point cloud data acquired by the distance sensor is converted directly into coordinate positions on the map data while the measurement axis is tilted, the entire object being measured, including the ground, will be tilted on the map data by the amount of the tilt of the measurement axis compared to the actual object.

[0007] This invention was made to solve the aforementioned problems and aims to easily and accurately generate three-dimensional map data of the surroundings of a work machine. [Means for solving the problem]

[0008] The map generation device according to the first invention includes a distance sensor that is attached to a work machine so as to intersect with the ground and measures the distance to each point in a point cloud that defines the surface shape of an object to be measured, including the ground, thereby acquiring point cloud data including the position information of each point; and a map generation unit that performs a map generation process to generate three-dimensional map data by converting the point cloud data acquired by the distance sensor from a measurement coordinate system in which the coordinate axis coaxial with the measurement axis of the distance sensor is the height axis to a map coordinate system in which the coordinate axis extending vertically in real space is the height axis. The map generation unit is configured to perform preprocessing before executing the map generation process, which includes a pre-data acquisition process that causes the distance sensor to acquire the point cloud data in advance, and an angle shift calculation process that calculates the angle of angle shift between the height axis of the measurement coordinate system and the height axis of the map coordinate system based on the point cloud data. When executing the map generation process, the unit is configured to perform a coordinate rotation process that converts the point cloud data acquired by the distance sensor after the preprocessing into the map coordinate system by rotating it around the origin of the measurement coordinate system by the amount of angle shift.

[0009] This configuration allows for easy and rapid acquisition of three-dimensional map data of the surrounding area of ​​a work machine by attaching the distance sensor to the work machine. Furthermore, this configuration enables the acquisition of highly accurate map data even if the measurement axis of the distance sensor attached to the work machine is tilted in the vertical direction. Specifically, in this configuration, when the map generation unit generates three-dimensional map data, the point cloud data acquired by the distance sensor is converted from a measurement coordinate system having a height axis coaxial with the measurement axis of the distance sensor to a map coordinate system with the vertical direction in real space as the height axis. This minimizes the influence of the tilt of the measurement axis of the distance sensor, even if it is tilted in the vertical direction, and enables the acquisition of highly accurate map data that reflects the actual shape of the ground. Moreover, in this configuration, the amount of angular deviation can be calculated based on the point cloud data acquired by the distance data acquisition process, eliminating the need to measure the tilt angle of the distance sensor's measurement axis (= the amount of angular deviation) using dedicated measuring equipment. Therefore, the amount of angular deviation can be calculated inexpensively and quickly.

[0010] In the second invention, it is preferable that the angular displacement calculation process in the first invention is a process that calculates the inclination angle of the ground defined by the point cloud data in the measurement coordinate system based on the positional information of a plurality of points corresponding to the ground among the point cloud data acquired in the prior data acquisition process, and calculates the difference between the calculated inclination angle of the ground and the actual inclination angle of the ground as the angular displacement amount.

[0011] This configuration allows for easy calculation of the angular displacement between the height axis of the measurement coordinate system and the height axis of the map coordinate system without the need for specialized measuring equipment. Specifically, the difference between the inclination angle of the ground in the measurement coordinate system based on point cloud data acquired by the distance sensor and the actual inclination angle of the ground is equal to the inclination angle of the distance sensor's measurement axis (= angular displacement between the height axis of the measurement coordinate system and the height axis of the map coordinate system). Focusing on this, the above configuration calculates the difference between the inclination angle of the ground in the measurement coordinate system and the actual inclination angle of the ground as the angular displacement between the height axis of the measurement coordinate system and the height axis of the map coordinate system, thereby facilitating the calculation of this angular displacement. The actual inclination angle of the ground may be measured in advance, or it may be detected by an angle detection sensor as described later.

[0012] The third invention is preferably configured such that, in the second invention, the work machine is further provided with a tilt angle detection sensor for detecting the tilt angle with respect to the horizontal direction, and when the map generation unit performs the angle displacement calculation process, it estimates the actual tilt angle of the ground based on the tilt angle detected by the tilt angle detection sensor, and calculates the difference between the calculated tilt angle of the ground in the measurement coordinate system and the estimated tilt angle of the ground as the amount of angle displacement.

[0013] With this configuration, even if the actual ground inclination angle is unknown when the map data generation unit performs the preprocessing, the actual ground inclination angle can be easily estimated based on the angle detected by the inclination angle detection sensor mounted on the work machine. Therefore, the amount of angular deviation can be easily calculated by the map generation unit based on the estimated actual ground inclination angle.

[0014] The fourth invention is preferably the first invention wherein the work machine is configured to suspend a load via a load suspension rope, the distance sensor is positioned within a predetermined measurement range such that a hanging portion of the load suspension rope that hangs vertically downward due to gravity is included, and the angular displacement calculation process is a process that calculates the angle of inclination of the hanging portion with respect to the measurement axis in the measurement coordinate system as the angular displacement amount, based on the point cloud data acquired in the pre-data acquisition process.

[0015] This configuration allows for easy calculation of the angular displacement between the height axis of the measurement coordinate system and the height axis of the map coordinate system without the need for specialized measuring equipment. Specifically, since the hanging portion of the suspension rope extends vertically due to gravity (in the same direction as the extension of the height axis of the ground coordinate system), the inclination angle of the measurement axis relative to this hanging portion can be calculated in the map generation unit, thereby allowing for the calculation of the inclination angle of the measurement axis in the vertical direction. This inclination angle of the measurement axis in the vertical direction is the inclination angle of the height axis of the measurement coordinate system relative to the height axis of the map coordinate system, and is equal to the angular displacement between the measurement coordinate system and the map coordinate system. Therefore, this configuration allows for easy calculation of the angular displacement between the height axis of the measurement coordinate system and the height axis of the map coordinate system using the hanging portion of the suspension rope, without the need to measure the inclination angle of the measurement axis using specialized measuring equipment.

[0016] The fifth invention is a process in which, in the second or fourth invention, the preprocessing further includes a height shift calculation process, the height shift calculation process converts the point cloud data acquired in the predata acquisition process into a map coordinate system by rotating it around the origin of the measurement coordinate system by the amount of angular shift, and then calculates the distance along the vertical direction from the ground to the mounting position of the distance sensor in the map coordinate system as the sensor mounting height based on the point cloud data converted into the map coordinate system, and calculates the difference between the calculated sensor mounting height and a predetermined design sensor mounting height of the distance sensor as the height shift amount from the design mounting position of the distance sensor, and it is preferable that the map generation unit is configured to correct the coordinate information of the point cloud data converted into the map coordinate system by the coordinate rotation process based on the height shift amount of the distance sensor calculated in the height shift calculation process when executing the map generation process.

[0017] With this configuration, the coordinate information of the point cloud data converted to the map coordinate system is corrected based on the difference (difference value) between the sensor mounting height in the design and the sensor mounting height in the map coordinate system after coordinate rotation processing, thereby enabling the acquisition of even more accurate map data. In other words, the position information of each point in the point cloud data acquired by the distance sensor is determined by the distance from the distance sensor to each point, so if the mounting height of the distance sensor deviates from the design mounting height, the vertical position of each point in the point cloud data converted to the map coordinate system will deviate from its actual position. In contrast, with the above configuration, 3D map data is generated in a way that corrects the positional deviation in the height direction from the design mounting position of the distance sensor, so it is possible to obtain map data that accurately reflects the vertical position of the object being measured, including the ground.

[0018] The sixth invention is the fifth invention, wherein the work machine comprises a main body and a work member rotatably supported on the main body, the distance sensor is attached to the work member, the preprocessing further includes a horizontal displacement calculation process, the horizontal displacement calculation process is a process that geometrically calculates the amount of horizontal displacement of the distance sensor from its designed mounting position using the displacement amount calculated in the height displacement calculation process, based on the assumption that the cause of the displacement is the vertical deflection deformation of the work member, and the map generation unit is preferably configured to correct the coordinate information of the point cloud data converted to the map coordinate system by the coordinate rotation process based on the amount of horizontal displacement of the distance sensor calculated in the horizontal displacement calculation process when executing the map generation process.

[0019] This configuration corrects the coordinate information of the point cloud data after conversion to a map coordinate system based on the horizontal displacement of the distance sensor from its designed mounting position, thereby enabling the acquisition of even more accurate map data. In other words, since the position information of each point in the point cloud data acquired by the distance sensor is determined by the distance from the distance sensor to each point, if the horizontal mounting position of the distance sensor deviates from its designed mounting position, the horizontal position of each point in the point cloud data after conversion to a map coordinate system will deviate from its actual position. In contrast, with the above configuration, 3D map data is generated in a way that corrects the horizontal displacement of the distance sensor, so it is possible to obtain map data that accurately reflects the horizontal position of the object being measured, including the ground.

[0020] Furthermore, according to the above configuration, the calculation of the horizontal positional displacement of the distance sensor in the map generation unit is performed based on the assumption that it is caused by vertical deflection deformation of the work member to which the distance sensor is attached. Here, the relationship between the amount of displacement of the mounting height of the distance sensor and the amount of horizontal positional displacement of the distance sensor when vertical deflection deformation occurs in the work member can be determined geometrically. Therefore, according to the above configuration, the amount of horizontal positional displacement of the distance sensor from the design mounting position can be easily calculated using the amount of displacement of the sensor mounting height calculated in the height displacement calculation process, without performing complex calculation processing. Thus, the computational burden on the map generation unit can be reduced and processing can be sped up.

[0021] The seventh invention is a process in which, in the fifth invention, the work machine has a reference part consisting of a predetermined surface or edge, the distance sensor is arranged such that the reference part is included within a predetermined measurement range, the preprocessing further includes a horizontal displacement calculation process, the horizontal displacement calculation process converts the point cloud data acquired in the predata acquisition process into a map coordinate system by rotating it around the origin of the measurement coordinate system by the amount of angular displacement, calculates the horizontal separation distance between the reference part and the mounting position of the distance sensor based on the point cloud data in the map coordinate system, calculates the difference between the calculated horizontal separation distance and the horizontal separation distance between the reference part and the mounting position of the distance sensor in the design as the amount of horizontal displacement of the distance sensor from the design mounting position, and preferably the map generation unit is configured to correct the coordinate information of the point cloud data converted into the map coordinate system by the coordinate rotation process based on the amount of horizontal displacement of the distance sensor calculated in the horizontal displacement calculation process when executing the map generation process.

[0022] With this configuration, the coordinate information of the point cloud data converted to the map coordinate system is corrected based on the amount of horizontal displacement of the distance sensor from its designed mounting position. As a result, even more accurate map data can be obtained, similar to the sixth invention described above. Furthermore, with this configuration, when calculating the amount of horizontal displacement of the distance sensor, the map generation unit first converts the point cloud data acquired in the pre-data acquisition process to the map coordinate system by rotating it around the origin of the measurement coordinate system by the amount of the angular displacement. Then, it calculates the horizontal separation distance between the reference part (e.g., the front of the cab) and the mounting position of the distance sensor in the map coordinate system. The difference between this calculated horizontal separation distance and the horizontal separation distance between the reference part and the mounting position of the distance sensor in the design is calculated as the amount of horizontal displacement of the distance sensor from its designed mounting position. Therefore, even if the cause of the horizontal displacement of the distance sensor is a factor other than the bending deformation of the work member (e.g., mounting error of the distance sensor), the amount of horizontal displacement of the distance sensor can be calculated with high accuracy.

[0023] In the eighth invention, in the sixth invention, the working machine includes a lower body, an upper swing body supported by the lower body so as to be swingable about a swing center axis extending in the vertical direction, and a work attachment including a base end portion supported by the upper swing body so as to be rotatable in the undulating direction and a tip end portion opposite to the base end portion. The distance sensor is attached to the tip end portion of the work attachment. The work attachment is configured to be able to change a working radius, which is a horizontal distance from the swing center axis to the tip end portion. Before executing the map generation process, the map generation unit changes the working radius of the work attachment to a plurality of predetermined working radii, and for each working radius, causes the map generation unit to execute the preprocessing, thereby generating correction data, which is data on the amount of angular deviation, the amount of positional deviation in the height direction, and the amount of positional deviation in the horizontal direction for each working radius. The map generation unit further includes a storage unit that stores the correction data generated by the map generation unit. When executing the map generation process, the map generation unit acquires the current working radius of the work attachment, and based on the correction data stored in the storage unit, acquires the amount of angular deviation, the amount of positional deviation in the height direction, and the amount of positional deviation in the horizontal direction corresponding to the working radius, and is preferably configured to execute the map generation process based on the acquired amounts of deviation.

[0024] According to this configuration, before executing the map generation process, by causing the map generation unit to execute preprocessing for each working radius of the work attachment, correction data, which is data on the amount of angular deviation, the amount of positional deviation in the height direction, and the amount of positional deviation in the horizontal direction for each working radius, is generated and stored in the storage unit. When the map generation unit executes the map generation process, each amount of deviation can be acquired accurately and quickly according to the working radius of the work attachment. Therefore, in the map generation unit, highly accurate map data can be generated regardless of changes in the working radius of the work attachment.

[0025] In the ninth invention, in the seventh invention, the working machine includes a lower body, an upper revolving body that is supported by the lower body so as to be rotatable about a turning center axis extending in the vertical direction, and a working attachment that includes a base end portion that is supported by the upper revolving body so as to be rotatable in the undulating direction and a tip end portion on the opposite side of the base end portion. The distance sensor is attached to the tip end portion of the working attachment. The working attachment is configured to be able to change a working radius, which is a horizontal distance from the turning center axis to the tip end portion. Before executing the map generation process, the map generation unit changes the working radius of the working attachment to a plurality of predetermined working radii, and for each working radius, causes the map generation unit to execute the preprocessing, thereby generating correction data that is the amount of angular deviation, the amount of positional deviation in the height direction, and the amount of positional deviation in the horizontal direction for each working radius. The map generation unit further includes a storage unit that stores the correction data generated by the map generation unit. When executing the map generation process, the map generation unit acquires the current working radius of the working attachment, and based on the correction data stored in the storage unit, acquires the amount of angular deviation, the amount of positional deviation in the height direction, and the amount of positional deviation in the horizontal direction corresponding to the working radius, and is preferably configured to execute the map generation process based on the acquired amounts of deviation.

[0026] According to this configuration, the same operational effects as those of the eighth invention can be obtained.

[0027] In the tenth invention, in any one of the first to fourth inventions, the working machine preferably includes a lower body, an upper revolving body that is supported by the lower body so as to be rotatable about a turning center axis extending in the vertical direction, and a working attachment that includes a base end portion that is supported by the upper revolving body so as to be rotatable in the undulating direction and a tip end portion on the opposite side of the base end portion, and the distance sensor is attached to the tip end portion of the working attachment.

[0028] With this configuration, the work attachment of the work machine can be used as a mechanism to change the position of the distance sensor, making it easy to generate map data around the work machine. Specifically, for example, by rotating the upper slewing body around the pivot axis, the distance sensor at the tip of the work attachment can be moved 360° around the pivot axis together with the upper slewing body. Therefore, 3D map data can be easily generated over 360° around the work machine. Furthermore, with the above configuration, by sequentially changing the working radius of the work attachment to a predetermined number of working radii, and rotating the upper slewing body around the pivot axis for each working radius, 3D map data can be generated at various working radii centered on the pivot axis of the work machine.

[0029] The 11th invention relates to a work machine, comprising: a distance sensor attached to the work machine such that its measuring axis intersects the ground, which acquires positional information of each point in a point cloud defining the surface shape of an object to be measured, including the ground, as point cloud data; and a map generation unit which performs a map generation process to generate three-dimensional map data by converting the point cloud data acquired by the distance sensor from a measurement coordinate system in which the coordinate axis coaxial with the measuring axis of the distance sensor is the height axis, to a map coordinate system in which the coordinate axis extending vertically in real space is the height axis. The map generation unit is configured to perform preprocessing before executing the map generation process, which includes a pre-data acquisition process that causes the distance sensor to acquire the point cloud data in advance, and an angle shift calculation process that calculates the amount of angular shift between the height axis of the measurement coordinate system and the height axis of the map coordinate system based on the point cloud data. When executing the map generation process, the map generation unit is configured to perform a coordinate rotation process that converts the point cloud data acquired by the distance sensor into a map coordinate system by rotating it around the origin of the measurement coordinate system by the amount of angular shift.

[0030] This configuration allows for the same effects and advantages as the first invention.

[0031] The map generation method according to the 12th invention comprises a point cloud data acquisition step, in which a distance sensor is attached to a work machine such that its measurement axis intersects the ground, and the distance to each point in a point cloud that defines the surface shape of an object to be measured, including the ground, is measured by the distance sensor to acquire point cloud data including the position information of each point; and a map generation step, in which the point cloud data acquired by the distance sensor is converted from a measurement coordinate system in which the coordinate axis coaxial with the measurement axis of the distance sensor is the height axis, to a map coordinate system in which the coordinate axis extending vertically in real space is the height axis, thereby generating three-dimensional map data. The map generation process includes a preprocessing process, which includes a pre-data acquisition process that causes the distance sensor to acquire the point cloud data in advance before executing the map generation process, and an angle shift calculation process that calculates the angle between the height axis of the measurement coordinate system and the height axis of the map coordinate system based on the point cloud data, and in the map generation process, when executing the map generation process, a coordinate rotation process is performed that converts the point cloud data acquired by the distance sensor in the point cloud data acquisition process into the map coordinate system by rotating it around the origin of the measurement coordinate system by the amount of the angle shift.

[0032] This configuration allows for the same effects and advantages as the first invention. [Effects of the Invention]

[0033] According to the present invention, three-dimensional map data of the surroundings of a work machine can be generated easily and accurately. [Brief explanation of the drawing]

[0034] [Figure 1] Figure 1 is a schematic diagram showing a crane (an example of a work machine) equipped with a map generation device according to an embodiment of the present invention. [Figure 2] Figure 2 is a block diagram showing the configuration of the control system, including the controller. [Figure 3] Figure 3 is a schematic diagram showing how point cloud data is acquired by a distance sensor when the measurement axis of the distance sensor is aligned in the vertical direction. [Figure 4] Figure 4 is a diagram equivalent to Figure 3, showing the distance sensor's measurement axis tilted by an angle θ with respect to the vertical direction. [Figure 5] Figure 5 is an explanatory diagram illustrating that when the measurement axis of the distance sensor is tilted by an angle θ with respect to the vertical direction, the point cloud data of the ground in the measurement coordinate system will be tilted compared to the actual ground. [Figure 6] Figure 6 is a schematic diagram showing an example of point cloud data in the measurement coordinate system displayed on the touch panel of the display device. [Figure 7] Figure 7 is an explanatory diagram illustrating the process for calculating this inclination angle θ (in Figure 7, the inclination angle perpendicular to the plane of the paper). [Figure 8] Figure 8 is a flowchart showing the processing flow for generating map data by the controller. [Figure 9] Figure 9 is a diagram corresponding to Figure 8, showing a modified example of Embodiment 1. [Figure 10] Figure 10 is a diagram corresponding to Figure 2, showing a modified example of Embodiment 1. [Figure 11] Figure 11 is a diagram corresponding to Figure 8, showing Embodiment 2. [Figure 12] Figure 12 is a schematic diagram showing the state in Embodiment 2 where the position of the distance sensor is shifted above the designed sensor mounting height due to the jib bending upward. [Figure 13] Figure 13 is an explanatory diagram illustrating the contents of the height displacement calculation process in Embodiment 2. [Figure 14] Figure 14 is an explanatory diagram illustrating the contents of the horizontal displacement calculation process in Modification 1 of Embodiment 2. [Figure 15] Figure 15 shows an example of correction data generated by the map generation unit in a modified example 2 of Embodiment 2. [Figure 16] Figure 16 is a diagram corresponding to Figure 8, showing Embodiment 3. [Figure 17] Figure 17 is an explanatory diagram illustrating the contents of the angular displacement calculation process in Embodiment 3. [Modes for carrying out the invention]

[0035] Embodiments of the present invention will be described in detail below with reference to the drawings.

[0036] (Embodiment 1) Figure 1 is a schematic diagram showing a crane 100 (an example of a work machine) equipped with a map generation device 210 according to an embodiment of the present invention.

[0037] The crane 100 comprises a crane body 10, a distance sensor 200 attached to the crane body 10, and a controller 202. The controller 202 is configured to generate three-dimensional map data of the area around the crane 100 based on point cloud data acquired by the distance sensor 200, as will be described later. In this embodiment, the distance sensor 200 and the controller 202 constitute a map generation device 210.

[0038] The crane body 10 comprises an upper slewing body 11, a lower traveling body 12 (an example of a lower body or body part) that supports the upper slewing body 11 so as to be rotatable, a work attachment 15 (also called a luffing body) including a boom 13 and a jib 14, and a mast 16 which is a boom luffing member.

[0039] The lower traveling body 12 is configured to travel on the ground by the rotation of its left and right crawlers. The upper slewing body 11 is supported by the lower traveling body 12 so as to be able to slewing around a central axis CL that extends vertically relative to the lower traveling body 12. A cab 17 is provided at the front end of the upper slewing body 11. The driver's seat for the crane 100 is located inside the cab 17.

[0040] Furthermore, the work attachment 15 includes a base end that is rotatably supported on the upper slewing body 11 in the luffing direction and a tip end opposite to the base end, and is detachably attached to the upper slewing body 11. As described above, in this embodiment, the work attachment 15 includes the boom 13 and the jib 14.

[0041] The boom 13 is of the so-called lattice type and is pivotally supported on the upper slewing body 11 around a rotation axis that extends in the left-right direction, with a boom foot pin (not shown) at its lower end as the pivot point.

[0042] The jib 14 is rotatably connected (pivoted) to the tip of the boom 13, and the axis of rotation of the jib 14 is a horizontal axis parallel to the axis of rotation of the boom 13 relative to the upper slewing body 11.

[0043] The crane 100 further includes a rear strut 21 and a front strut 22 rotatably supported at the tip of the boom 13, a jib guideline 23 stretched between the tip of the front strut 22 and the tip of the jib 14, a rear strut guideline 24 stretched between the tip of the rear strut 21 and the boom 13, a boom guideline 25 stretched between the tip of the boom 13 and the tip of the mast 16, a jib luffing rope 26 routed between the tip of the front strut 22 and the tip of the rear strut 21, a boom luffing rope 27 routed between the tip of the mast 16 and the upper slewing body 11, and a main hoisting rope 28 hanging from the tip of the jib 14 and supporting the suspended load W via a hook (not shown). The main hoisting rope 28 is connected to a main hoisting winch (not shown) located near the base of the boom 13 via a point sheave provided at the tip of the jib 14.

[0044] The crane 100 further includes a main hoisting winch that hoists and lowers the suspended load W by winding and unwinding the main hoisting rope 28, a jib luffing winch (not shown) that hoists and lowers the jib 14 around its base end by winding and unwinding the jib luffing rope 26, and a boom luffing winch (not shown) that hoists and lowers the boom 13 around its base end by winding and unwinding the boom luffing rope 27. The operation of these various winches is controlled by the controller 202 in accordance with the operations performed by the operator on the operating device.

[0045] [Distance sensor configuration] The distance sensor 200 is mounted on the tip of the jib 14. The distance sensor 200 is biased by a damper so that its measuring axis K is oriented in the vertical direction.

[0046] The distance sensor 200 measures the distance to the object being measured, including the ground, and acquires positional information (coordinate position in the measurement coordinate system) for each point in the point cloud that defines the surface shape of the object being measured, and outputs the acquired positional information to the controller 202.

[0047] The distance sensor 200 is configured, for example, using LIDAR (Light Detection and Ranging). The distance sensor 200 rotates around the measurement axis K and emits laser light from a light-emitting point located coaxial with the rotation axis over a predetermined horizontal angle α. The distance sensor 200 then measures the time from the emission of the laser light to the reception of the reflected light, thereby obtaining the distance from the light-emitting point to a number of reflection points (i.e., each point in the point cloud that defines the surface shape of the object being measured), and obtains point cloud data including the coordinate information of each point based on the obtained distance. The measurement axis K is defined, for example, as the axis aligned with the direction in which the measurement sensitivity of the distance to the object being measured is greatest. In this example, the measurement axis K of the distance sensor 200 coincides with the optical axis of the light emitted from the light-emitting point.

[0048] The point cloud data acquired by the distance sensor 200 is data that defines the coordinate position of each point in the point cloud in the measurement coordinate system. Here, the measurement coordinate system is a three-dimensional Cartesian coordinate system having a height axis coaxial with the measurement axis K of the distance sensor 200 and with the design mounting position of the distance sensor 200 as its origin (see Figure 3 described later). In the following, the X' axis, Y' axis, and Z' axis are defined as the three orthogonal axes constituting the measurement coordinate system, and of these, the Z' axis is defined as the height axis. Note that the origin of the measurement coordinate system does not necessarily have to be set at the design mounting position; for example, it may be set at the center position of the tip of the distance sensor 200.

[0049] [Controller Configuration] The controller 202 functions as a device that comprehensively controls the operation of the crane 100, and also functions as part of a map generation device 210 that generates three-dimensional map data of the area around the crane 100.

[0050] Figure 2 is a block diagram showing the configuration of the control system including the controller 202. The controller 202 is connected to the operating device 203, the display device 204, and the distance sensor 200 so as to be able to send and receive signals.

[0051] The operating device 203 is a device for an operator to operate the crane 100 and is installed inside the cab 17 of the crane 100. The operating device 203 further includes a mode setting unit 203a for setting a map generation mode and a pre-processing mode, which will be described later, as operating modes for the crane 100. The operating device 203 receives an operation from the operator and outputs the operation signal to the controller 202.

[0052] The display device 204 has a touch panel 204a located inside the cab 17 of the crane 100. The display device 204 displays information necessary for operating the crane 100, as well as map data generated by the map generation unit 202b (described later), on the touch panel 204a in a visible manner. The operator can also perform various setting operations through the touch panel 204a. The touch panel 204a is configured to detect pressing operations by the operator and output the operation signal to the controller 202.

[0053] The controller 202 is composed of a computer having a CPU, ROM, and RAM, and the CPU operates to have the drive control unit 202a and map generation unit 202b functionally by executing a predetermined program. The drive control unit 202a drives various actuators (for example, each winch, the travel motor, and the slewing motor of the upper slewing body 11, etc.) to cause the crane 100 to perform an action corresponding to the operation performed by the operator, based on the operation signal received from the operating device 203.

[0054] The map generation unit 202b receives point cloud data output from the distance sensor 200 and performs a map generation process to generate 3D map data based on the received point cloud data. Specifically, in this map generation process, the point cloud data received from the distance sensor 200 is converted from the measurement coordinate system to the map coordinate system to generate map data.

[0055] The map coordinate system is a three-dimensional Cartesian coordinate system with the vertical direction as the height axis. In this embodiment, the origin of the map coordinate system coincides with the design mounting position of the distance sensor 200. In the following description, the three orthogonal axes constituting this map coordinate system are defined as the X axis, Y axis, and Z axis, with the Z axis defined as the height axis (see Figure 3 described later). In the following description, coordinate values ​​in the map coordinate system are expressed without a single quote, for example (xa, ya, za), while coordinate values ​​in the measurement coordinate system are expressed with a single quote, for example (xa', ya', za'), to distinguish between the coordinate values ​​of the two coordinate systems.

[0056] Figure 3 is a schematic diagram showing how point cloud data is acquired by the distance sensor 200 when the measurement axis K of the distance sensor 200 is aligned vertically, and Figure 4 is a diagram equivalent to Figure 3 showing the state when the measurement axis K of the distance sensor 200 is tilted by an angle θ with respect to the vertical direction. In each figure, the shape of the crane 100 is simplified as appropriate for the sake of clarity.

[0057] As shown in Figure 3, when the distance sensor 200 is in its designed mounting position (i.e., in a position where the measurement axis K coincides vertically), the map coordinate system (XYZ coordinate system) and the measurement coordinate system (X'Y'Z' coordinate system) coincide. Therefore, map data (point cloud data in the map coordinate system) can be generated by using the coordinates (xa', ya', za') of each point in the point cloud data acquired by the distance sensor 200 (i.e., point cloud data in the measurement coordinate system) directly as the coordinates (xa, ya, za) of each point in the map coordinate system.

[0058] On the other hand, as shown in Figure 4, if the measurement axis K of the distance sensor 200 is tilted by an angle θ in the vertical direction due to assembly errors of the distance sensor 200 or deterioration of the damper's biasing function, the map coordinate system (XYZ coordinate system) and the measurement coordinate system (X'Y'Z' coordinate system) will not coincide. That is, the Z' axis, which is the height axis in the measurement coordinate system, will be tilted by the tilt angle θ of the measurement axis K relative to the Z axis, which is the height axis in the map coordinate system. Therefore, if the point cloud data acquired by the distance sensor 200 in the measurement coordinate system is used directly as point cloud data in the map coordinate system, map data will be generated that does not reflect the actual shape of the ground. Note that in Figure 4, the tilt angle θ of the measurement axis K is shown in the YZ plane as an example, but the tilt direction of the measurement axis K is not limited to the YZ plane.

[0059] Figure 5 is an explanatory diagram designed to make this easier to understand visually. The thick solid lines extending horizontally in the figure correspond to the actual shape of the ground, and the black dots represent the point cloud data of the ground in the measurement coordinate system acquired by the distance sensor 200. From this figure, it can be seen that the ground represented by the point cloud data in the measurement coordinate system is tilted relative to the actual ground by an angle θ of inclination with respect to the vertical direction of the measurement axis K. Therefore, if the point cloud data in the measurement coordinate system is used directly as point cloud data (map data) in the map coordinate system, the ground on the map data will be displayed tilted more than the actual ground in the horizontal direction.

[0060] Therefore, in this embodiment, in order to resolve the above-mentioned problem caused by the Z' axis of the measurement coordinate system and the Z axis of the map coordinate system not coinciding (i.e., having a misalignment angle θ), the map generation unit 202b is configured to perform coordinate rotation processing. In this coordinate rotation processing, when converting the point cloud data in the measurement coordinate system acquired by the distance sensor 200 to the map coordinate system, the point cloud data is rotated around the origin of the measurement coordinate system by the aforementioned misalignment angle θ so that the ground in the measurement coordinate system matches the horizontal plane which is the actual ground. This misalignment angle θ is calculated by the map generation unit 202b in the pre-processing mode described later.

[0061] In other words, the crane 100 is configured to be switchable between a pre-processing mode for pre-calculating the displacement angle θ and a map generation mode for executing the map generation process after the pre-processing mode is completed. Each mode can be switched by the operator operating the mode setting unit of the control device 203.

[0062] In the aforementioned pre-processing mode, the map generation unit 202b performs a pre-data acquisition process that causes the distance sensor 200 to acquire pre-prepared point cloud data of the horizontal ground.

[0063] The map generation unit 202b then displays the acquired point cloud data along with the measurement coordinate system on the touch panel 204a of the display device 204. Figure 6 is a schematic diagram showing an example of the point cloud data displayed on the touch panel 204a.

[0064] In this example, the point cloud data is displayed in a two-dimensional coordinate system (Y'-Z' plane) viewed from the X' axis direction, but this is not the only option. For example, it could be displayed in a three-dimensional perspective view so that the three-dimensional position of each point can be visually confirmed. The map generation unit 202b displays the point cloud data along with the message "Please touch and select the two points in the point cloud data that make up the ground that have the maximum distance in the Z' direction." on the touch panel 204a. When the operator selects (presses) the two points a1 and b1, the touch panel 204a sends a selection signal (press signal) for the two points a1 and b1 to the controller 202.

[0065] The map generation unit 202b recognizes the positions of the two points a1 and b1 on the touch panel 204a based on the selection signals of the two points a1 and b1 received from the touch panel 204a, and identifies the coordinate positions of the two points a1 and b1 in the measurement coordinate system based on the recognized positions. Then, based on the identified coordinate positions, it calculates the inclination angle θ of the straight line connecting the two points a1 and b1 with respect to the X'-Y' plane (a plane that includes the Y' axis in Figure 6 and is perpendicular to the plane of the paper).

[0066] In this embodiment, the operator selects the two points a1 and b1, but this is not the only option. The map generation unit 202b may automatically select the two points a1 and b1 based on image processing or the like. The automatic selection process for the two points a1 and b1 does not necessarily select the two points that have the maximum distance in the Z' axis direction. That is, for example, (i) the two ends of the point cloud when viewed from the X' direction may be selected as points a1 and b1, (ii) the center positions of a predetermined number of point clouds from both ends of the point cloud when viewed from the X' direction may be selected as points a1 and b1, (iii) points located at predetermined distances from both ends of the point cloud when viewed from the X' direction may be selected as points a1 and b1, or (iv) points a1 and b1 may be calculated to correspond to the average value (or median, etc.) of the X', Y', and Z' coordinates of the point clouds that constitute a predetermined range on both ends of the point cloud when viewed from the X' direction. Since the points constituting the point cloud are not necessarily aligned in a straight line when viewed from the X' direction, the processes described in (ii) to (iv) above are particularly useful from the standpoint of correcting for such dispersion.

[0067] Figure 7 is an explanatory diagram illustrating the calculation process for the inclination angle θ (the inclination angle perpendicular to the plane of the paper in Figure 7, which is not shown in Figure 7), where points a1 and b1 correspond to the two selected points. As shown in this figure, in order to simplify the calculation process, the two selected points a1 and b1 are rotated by an intersection angle φ to be converted into corresponding points a2 and b2 on the Y' axis, and then the inclination angle θ is calculated based on the following equation (1).

[0068]

number

[0069] Furthermore, the transformation formula for converting the two selected points a1 and b1 to their corresponding points a2 and b2 is given by the rotation matrix shown in equation (2) below.

[0070]

number

[0071] The inclination angles θ of the two selected points a1 and b1 with respect to the X'-Y' plane are then obtained as the inclination angle θ of the measurement axis K of the distance sensor 200 with respect to the vertical direction (in other words, the displacement angle θ (angle of displacement) which is the angle between the Z' axis of the measurement coordinate system and the Z axis of the map coordinate system). This completes the series of processes in the pre-processing mode.

[0072] In the map generation mode, which is executed after the pre-processing mode, the map generation unit 202b causes the distance sensor 200 to acquire point cloud data of the ground to be measured. Then, the map generation unit 202b rotates the entire point cloud data (each point constituting the point cloud data) received from the distance sensor 200 by the displacement angle θ around the X' axis of the measurement coordinate system based on the following equation (3).

[0073]

number

[0074]

number

[0075] [Explanation of the flowchart] Figure 8 is a flowchart showing the processing flow for generating map data by the controller 202. Steps SA2 to SA8 described below correspond to pre-processing, and steps SA11 and SA12 correspond to map data generation processing.

[0076] In step SA1, based on the operation signal from the control device 203, it is determined whether the pre-processing mode is set as the operating mode of the crane 100. If the determination is NO, the process proceeds to step SA11; otherwise, the process proceeds to step SA2.

[0077] In step SA2, a pre-data acquisition process is performed to cause the distance sensor 200 to acquire point cloud data of the ground. In this pre-data acquisition process, a level ground surface is prepared in advance, and the distance sensor 200 is instructed to acquire point cloud data using this ground surface as the measurement target.

[0078] In step SA3, the point cloud data acquired in step SA2 (i.e., point cloud data in the measurement coordinate system) is displayed on the touch panel 204a of the display device 204 along with the measurement coordinate system (see Figure 6). In addition to this display, a message prompting the user to select the two points on the ground as described above is also displayed on the touch panel 204a.

[0079] In step SA4, after the display processing in step SA3, it is determined whether or not the selection signals (press signals) for the two points have been received from the touch panel 204a within a predetermined time. If the result is NO, the process returns to step SA1; if the result is YES, the process proceeds to step SA5. If the selection signals are not received within the predetermined time, instead of immediately returning to step SA1, the system may first prompt the user to select the two points by displaying a screen message or an audio alarm. If the selection signals for the two points are still not received, the loop may be interrupted and the process returns to step SA1.

[0080] In step SA5, based on the selection signals (pressure signals) of the two points received from the touch panel 204a, the positions of the two selected points a1 and b1 on the touch panel 204a are recognized, and the coordinate values ​​of the selected point a1 (xa1', ya1', za1') and the selected point b1 (xb1', yb1', zb1') in the measurement coordinate system are identified. Then, the two identified selected points a1 and b1 are converted into two corresponding points a2 and b2 on the Y' axis based on equation (2) as described above (see Figure 7), and the coordinate values ​​of the corresponding point a2 (xa2', ya2', za2') and the corresponding point b2 (xa2', ya2', za2') are obtained.

[0081] Step SA6 determines whether the positions of the two corresponding points a2 and b2 in the Y' axis direction are different. Specifically, it determines whether ya2'-yb2'≠0. If this determination is NO, the process proceeds to step SA9, where an error is displayed on the touch panel 204a, and then the process returns to step SA3. On the other hand, if this determination is YES, the process proceeds to step SA7. Note that when determining whether ya2'-yb2'≠0, even if ya2'-yb2' does not exactly match 0, it may be considered 0 if it falls within a predetermined error range of + / - relative to 0.

[0082] Step SA7 determines whether the positions of the two corresponding points a2 and b2 in the Z' axis direction are different. Specifically, it determines whether za2'-zb2'≠0. If this determination is NO, the process proceeds to step SA10, where it is determined that there is no offset angle θ between the Z' axis of the measurement coordinate system and the Z axis of the map coordinate system (i.e., offset angle θ=0), and then the process returns to step SA1. Note that when determining whether za2'-zb2'≠0, even if za2'-zb2' does not exactly match 0, it may be considered 0 if it falls within a predetermined error range of + / - relative to 0.

[0083] In step SA8, based on the coordinate values ​​of corresponding points a2 and b2 obtained in step SA5, the calculation using equation (1) is performed to calculate the inclination angle θ of the two corresponding points a2 and b2 with respect to the X'-Y' plane as the inclination angle of the measurement axis K of the distance sensor 200 with respect to the vertical direction (in other words, the angle of displacement θ (angle of displacement) which is the angle between the Z' axis of the measurement coordinate system and the Z axis of the map coordinate system), and then the process returns to step SA1. This process in step SA8 corresponds to the angle of displacement calculation process.

[0084] In step SA11, which proceeds if the determination in step SA1 is NO, the mode setting unit 203a determines that the map generation mode is set, and the distance sensor 200 is instructed to perform the process of acquiring point cloud data of the ground to be measured. This point cloud data acquisition process may be performed, for example, while rotating the upper slewing body 11 of the crane 100 360° around its pivot axis CL.

[0085] In step SA12, map data is generated by converting the point cloud data acquired in step SA11 into a map coordinate system using coordinate rotation processing based on equations (3) and (4). If it is determined in step SA10 that there is no displacement angle θ, then θ=0 should be substituted into equations (3) and (4).

[0086] In step SA13, the map data generated in step SA12 is displayed on the touch panel 204a, and then the process returns to step SA1.

[0087] [Effects and Effects] As described above, in this embodiment, the map generation device 210 includes a distance sensor 200 attached to the crane 100 such that the measurement axis K intersects the ground, and a map generation unit 202b (controller 202) that performs a map generation process to generate three-dimensional map data by converting the point cloud data acquired by the distance sensor 200 from a measurement coordinate system in which the coordinate axis coaxial with the measurement axis K of the distance sensor 200 is the height axis, to a map coordinate system in which the coordinate axis extending vertically in real space is the height axis. Before executing the map generation process, the map generation unit 202b performs preprocessing including a pre-data acquisition process that causes the distance sensor 200 to acquire the point cloud data in advance, and an angle displacement calculation process that calculates the displacement angle θ, which is the angle between the Z' axis of the measurement coordinate system and the Z axis of the map coordinate system, based on the point cloud data. The map generation unit 202b is configured to perform a coordinate rotation process in which, when executing the map generation process, it rotates the point cloud data acquired by the distance sensor 200 around the origin of the measurement coordinate system by the offset angle θ to convert it into a map coordinate system.

[0088] With this configuration, by attaching the distance sensor 200 to the crane 100, three-dimensional map data of the area around the crane 100 can be easily and quickly acquired. Furthermore, with this configuration, even if the measurement axis K of the distance sensor 200 attached to the crane 100 is tilted in the vertical direction, the point cloud data can be converted from a measurement coordinate system where the measurement axis K of the distance sensor 200 is the height axis to a map coordinate system where the vertical direction is the height axis by coordinate rotation processing, thereby obtaining highly accurate map data that eliminates the influence of the tilt of the measurement axis K of the distance sensor 200. Moreover, by calculating the rotation angle when executing the coordinate rotation processing (i.e., the offset angle θ between the Z' axis of the measurement coordinate system and the Z axis of the map coordinate system) based on the point cloud data acquired in the pre-data acquisition processing, the offset angle can be easily and quickly calculated without forcing the operator to measure the offset angle.

[0089] Furthermore, in this embodiment, the angle displacement calculation process (processing in step SA3) calculates the inclination angle of the ground in the measurement coordinate system based on the coordinate values ​​of two selected points a1 and b1 that constitute the ground selected by the operator from the point cloud data acquired in the pre-data acquisition process (processing in step SA2) (an example of coordinate information of multiple points), and calculates the difference between the calculated inclination angle of the ground in the measurement coordinate system and the actual inclination angle of the ground as the displacement angle θ.

[0090] This configuration allows for easy calculation of the offset angle θ between the Z' axis of the measurement coordinate system and the Z axis of the map coordinate system without the need for specialized measuring equipment. Specifically, the difference between the inclination angle of the ground in the measurement coordinate system based on point cloud data acquired by the distance sensor 200 and the actual inclination angle of the ground is equal to the inclination angle of the measurement axis K of the distance sensor 200 (i.e., the offset angle θ between the Z' axis of the measurement coordinate system and the Z axis of the map coordinate system). Focusing on this, the above configuration calculates the difference between the inclination angle of the ground in the measurement coordinate system (horizontal in this embodiment) and the actual inclination angle of the ground as the offset angle θ between the Z' axis of the measurement coordinate system and the Z axis of the map coordinate system, thereby making it easy to calculate the offset angle θ.

[0091] In this embodiment, the crane 100 includes a lower traveling body 12, an upper slewing body 11 supported on the lower traveling body 12 so as to be able to rotate around a central pivot axis CL extending in the vertical direction, and a work attachment 15 including a base end and a tip end opposite to the base end, which are supported on the upper slewing body 11 so as to be able to rotate in the luffing direction, and the distance sensor 200 is attached to the tip end of the work attachment 15.

[0092] With this configuration, the work attachment 15 of the crane 100 can be used as a change mechanism to change the position of the distance sensor 200, making it easy to generate map data around the crane 100. Specifically, for example, by rotating the upper slewing body 11 around the slewing center axis CL, the distance sensor 200 at the tip of the work attachment 15 can be moved 360° around the slewing center axis CL together with the upper slewing body 11. This makes it easy to generate three-dimensional map data over 360° around the crane 100. Furthermore, with the above configuration, by sequentially changing the working radius R (see Figure 1) of the work attachment 15 to a predetermined number of working radii R, and rotating the upper slewing body 11 around the slewing center axis CL for each working radius R, three-dimensional map data can be generated at various working radii R centered on the slewing center axis CL of the crane 100. The working radius R is the horizontal distance from the pivot axis CL of the upper rotating body 11 to the tip of the work attachment 15.

[0093] (modified version) Figure 9 is a diagram corresponding to Figure 8 showing a modified example of Embodiment 1, and Figure 10 is a diagram corresponding to Figure 2 showing the same modified example. This modified example differs from Embodiment 1 in that, in the process of calculating the offset angle θ between the Z' axis in the measurement coordinate system and the Z axis in the map coordinate system, the detected value from the tilt angle detection sensor 205 mounted on the crane 100 is used.

[0094] The tilt angle detection sensor 205 (see Figure 10) is installed, for example, inside the cab 17 of the upper rotating body 11 to detect the tilt angle of the upper rotating body 11 with respect to the horizontal plane. The tilt angle detection sensor 205 then outputs the detected tilt angle information to the controller 202.

[0095] Referring to Figure 9, the processing flow executed by the controller 202 of this modified example 1 will be explained. Note that in the following explanation, processing similar to that in Embodiment 1 will be omitted as appropriate.

[0096] In step SB1, the same process as in step SB1 of Embodiment 1 is performed.

[0097] In step SB2, the tilt angle of the upper rotating body 11 detected by the tilt angle detection sensor 205 is obtained, and the obtained tilt angle is estimated as the actual tilt angle of the ground.

[0098] Steps SB3 to SB8 perform the same processing as steps SA2 to SA7.

[0099] In step SB9, the map generation unit 202b calculates the inclination angle θ of the two corresponding points a2 and b2 with respect to the X'-Y' plane by performing calculations according to equation (1) based on the coordinate values ​​of the corresponding points a2 and b2 obtained in step SB5. The map generation unit 202b then calculates the difference between the calculated inclination angle θ and the actual ground inclination angle estimated in step SB2 as the inclination angle θ of the measurement axis K of the distance sensor 200 in the vertical direction (in other words, the displacement angle θ (angle of displacement) which is the angle between the Z' axis of the measurement coordinate system and the Z axis of the map coordinate system), and then returns to step SB1.

[0100] Steps SB10 to SB14 perform the same processing as steps SA9 to SA13.

[0101] [Effects and Effects] In this embodiment, the map generation device 210 further includes a tilt angle detection sensor 205 provided on the crane 100 for detecting the tilt angle with respect to the horizontal direction. When the map generation unit 202b performs the angle displacement calculation process, it estimates the actual tilt angle of the ground based on the tilt angle detected by the tilt angle detection sensor 205. The map generation unit 205a is configured to calculate the difference between the tilt angle of the ground in the measurement coordinate system calculated based on the coordinate values ​​of the two selected points a1 and b1, and the estimated tilt angle of the ground, as the displacement angle θ.

[0102] With this configuration, the map generation unit 202b can easily estimate the actual ground inclination angle based on the angle detected by the inclination angle detection sensor 205 mounted on the crane 100. Therefore, even if the actual ground inclination angle is unknown when the map data generation unit performs the preprocessing, the displacement angle θ can be easily calculated based on the estimated ground inclination angle.

[0103] (Embodiment 2) Figure 11 is a diagram corresponding to Figure 8, showing Embodiment 2. This embodiment differs from Embodiment 1 in that, in the pre-processing mode, in addition to the angular displacement calculation process, a height displacement calculation process and a horizontal displacement calculation process are further executed. In the following flowchart description, explanations of processes similar to those in Embodiment 1 will be omitted as appropriate.

[0104] Steps SC1 to SC8 perform the same processing as steps SA1 to SA8 of Embodiment 1.

[0105] Step SC9 executes the height displacement calculation process. This process calculates the amount of vertical displacement in the height direction of the point cloud data after conversion to the map coordinate system, which is caused by the vertical displacement of the distance sensor 200 relative to the designed sensor mounting height.

[0106] As an example, consider a situation where the jib 14 bends upward, causing the position of the distance sensor 200 to shift above the designed sensor mounting height. Figure 12 is a schematic diagram illustrating this situation visually, where the solid line in the figure shows the jib 14 bent upward, and the dashed line shows the jib 14 not bent.

[0107] Thus, when the sensor mounting height of the distance sensor 200 is shifted upwards from the designed sensor mounting height, the distance from the distance sensor 200 to the ground becomes longer. Therefore, if the point cloud data is converted to a map coordinate system assuming that there is no positional shift of the distance sensor 200, the position of the point cloud data will be located below the actual position of the ground. Figure 13 is an explanatory diagram that clearly illustrates this, and the numerous black circles in the figure represent the point cloud data of the ground in the map coordinate system.

[0108] In step SC9, as shown in Figure 13, the vertical displacement Δz between the height position of the point cloud data after conversion to map coordinates and the actual ground height is calculated. Specifically, the map generation unit 202b calculates the distance along the vertical direction between the ground of the point cloud data converted to map coordinates and the mounting position of the distance sensor 200 as the sensor mounting height Z1, and calculates the difference between the calculated sensor mounting height Z1 and the predetermined design sensor mounting height Z2 of the distance sensor 200 as the vertical displacement Δz.

[0109] Next, in step SC10, a horizontal displacement calculation process is performed. This horizontal displacement calculation process calculates the amount of horizontal displacement Δy of the point cloud data after conversion to the map coordinate system, which is caused by the horizontal displacement of the distance sensor 200 from its designed mounting position.

[0110] Specifically, assuming that the jib 14 is undergoing vertical deflection deformation as shown in Figure 12, the horizontal displacement Δy of the distance sensor 200 from its design mounting position is calculated based on the following equation (5).

[0111]

number

[0112] In step SC15, the point cloud data converted to map coordinates in step SC14 is corrected based on the vertical displacement Δz calculated in step SC9 and the horizontal displacement Δy calculated in step SC10. Specifically, the horizontal displacement Δy is subtracted (or added) from the y coordinate of each point in the point cloud data, and the vertical displacement Δz is subtracted (or added) from the Z coordinate of each point.

[0113] Step SC16 performs the same process as in Step SA13.

[0114] [Effects and Effects] As described above, in this embodiment, the map generation unit 202b further performs a height shift calculation process as a preprocessing step. In the height shift calculation process, the point cloud data acquired in the pre-data acquisition process is converted to a map coordinate system by rotating it around the origin of the measurement coordinate system by the shift angle θ. Then, based on the point cloud data converted to the map coordinate system, the distance along the vertical direction between the ground and the mounting position of the distance sensor 200 in the map coordinate system is calculated as the sensor mounting height Z1. The amount of difference Δz between the calculated sensor mounting height Z1 and the predetermined design sensor mounting height Z2 of the distance sensor 200 is calculated (step SC9). The map generation unit 202b is configured to correct the coordinate information of the point cloud data converted to the map coordinate system by the coordinate rotation process based on the amount of difference of the sensor mounting height calculated in the height shift calculation process when executing the map generation process (step SC15).

[0115] With this configuration, the coordinate information of the point cloud data converted to the map coordinate system is corrected based on the difference Δz (i.e., the difference value) between the sensor mounting height Z2 in the design and the sensor mounting height Z1 in the map coordinate system after coordinate rotation processing, thereby enabling the acquisition of even more accurate map data. In other words, since the position information of each point in the point cloud data acquired by the distance sensor 200 is determined by the distance from the distance sensor 200 to each point, if the mounting height of the distance sensor 200 deviates from the design mounting height, the vertical position of the point cloud data converted to the map coordinate system will deviate from the actual position. In contrast, with the above configuration, 3D map data is generated in a way that corrects the amount of deviation in the mounting height of the distance sensor 200, so it is possible to obtain map data that accurately reflects the vertical position of the object being measured, including the ground.

[0116] Furthermore, in this embodiment, the map generation unit 202b further performs a horizontal displacement calculation process as a preprocessing step. In the horizontal displacement calculation process, the amount of horizontal displacement Δy of the distance sensor 200 from its designed mounting position is geometrically calculated using the displacement amount Δz calculated in the height displacement calculation process, based on the assumption that the cause of the displacement is the vertical deflection deformation of the work member (step SC10). The map generation unit 202b is configured to correct the coordinate information of the point cloud data converted to the map coordinate system by the coordinate rotation process based on the amount of horizontal displacement Δy of the distance sensor 200 calculated in the horizontal displacement calculation process when executing the map generation process (step SC15).

[0117] With this configuration, the coordinate information of the point cloud data converted to a map coordinate system is corrected based on the horizontal displacement Δy of the distance sensor 200 from its designed mounting position, thereby enabling the acquisition of even more accurate map data. In other words, the position information of each point in the point cloud data acquired by the distance sensor 200 is determined by the distance from the distance sensor 200 to each point. Therefore, if the horizontal mounting position of the distance sensor 200 deviates from its designed mounting position, the horizontal position of the point cloud data converted to a map coordinate system will deviate from its actual position. In contrast, with the above configuration, 3D map data is generated in a way that corrects the horizontal displacement Δy of the distance sensor 200, so it is possible to obtain map data that accurately reflects the horizontal position of the object being measured, including the ground.

[0118] Furthermore, according to the above configuration, the calculation of the horizontal positional displacement Δy of the distance sensor 200 in the map generation unit 202b is performed based on the assumption that it is caused by vertical deflection deformation of the jib 14 (an example of a work member) to which the distance sensor 200 is attached. Here, the relationship between the amount of displacement of the mounting height of the distance sensor 200 and the horizontal positional displacement Δy of the distance sensor 200 when vertical deflection deformation occurs in the jib 14 can be defined by the above-mentioned equation (5) using simple trigonometric functions. Therefore, according to the above configuration, the horizontal positional displacement Δy of the distance sensor 200 from the design mounting position can be easily calculated using the amount of displacement of the sensor mounting height calculated in the height displacement calculation process without performing complex calculation processing. Thus, the calculation processing by the map generation unit 202b can be accelerated.

[0119] (Modification 1 of Embodiment 2) Figure 14 is an explanatory diagram illustrating the contents of the horizontal displacement calculation process in Modification 1 of Embodiment 2.

[0120] As shown in this figure, in this modified example, first, the posture of the work attachment 15 is adjusted so that the reference part J of the crane 100 is included in the measurement range (a predetermined range based on the measurement axis K) of the distance sensor 200. Then, in this state, the pre-data acquisition process is performed by the distance sensor 200 to acquire point cloud data including the reference part J. In this example, the reference part J is set to the front of the cab 17, but it is not limited to this, and may be any part of the crane 100, such as the end face or edge.

[0121] Then, in the horizontal displacement calculation process, the point cloud data acquired in the pre-data acquisition process is converted to the map coordinate system by the coordinate rotation process described above. After this conversion, the point cloud data corresponding to the reference area J is identified, and based on the identified point cloud data, the horizontal separation distance Y1, which is the horizontal distance between the reference area J and the mounting position of the distance sensor 200 in the map coordinate system, is calculated. The difference between the calculated horizontal separation distance Y1 and the horizontal separation distance Y2 between the reference area and the mounting position of the distance sensor 200 in the design is calculated as the horizontal displacement amount Δy from the design mounting position of the distance sensor 200.

[0122] [Effects and Effects] According to this modified example, the coordinate information of the point cloud data converted to a map coordinate system is corrected based on the horizontal displacement Δy of the distance sensor 200 from its designed mounting position, thereby achieving the same effects as in Embodiment 2.

[0123] Furthermore, according to this modified example, the horizontal displacement Δy of the distance sensor 200 can be calculated without using a geometric calculation formula that assumes the deflection of the jib 14, as in the second embodiment described above. Therefore, even if the cause of the horizontal displacement of the distance sensor 200 is a factor other than the deflection deformation of the jib 14 (for example, mounting error of the distance sensor 200), the horizontal displacement of the distance sensor 200 can be calculated with high accuracy.

[0124] (Modification 2 of Embodiment 2) In the above embodiment 2, the working radius R of the work attachment 15 is fixed, and various displacement amounts (the displacement angle θ, the vertical position displacement amount Δz of the distance sensor 200, and the horizontal position displacement amount Δy) are calculated in the pre-processing mode, and then the map generation process is executed based on the calculated displacement amounts. However, this is not the only method, and processing in the pre-processing mode may be performed for each of a set of pre-configured working radii R, and the displacement amount corresponding to each working radius R may be stored in advance in a storage unit (RAM, hard disk, etc.) as correction data D.

[0125] In this case, the map generation unit 202b is configured to generate correction data D that associates each working radius R with the displacement angle θ, the vertical displacement amount Δz, and the horizontal displacement amount Δy for each working radius R, by changing the working radius R of the work attachment 15 to a plurality of predetermined working radii R, and performing the processing in the pre-processing mode for each working radius R. Figure 15 is an example of the correction data generated by the map generation unit 202b. In this example, the working radius R is shown to be changed at 1m intervals, but the interval of the working radius R is not limited to this and may be any value.

[0126] The map generation unit 202b is configured to perform the map generation process in the map generation mode by calculating the current working radius R of the work attachment 15, and based on the correction data D stored in the storage unit, acquire the amount of displacement (displacement angle θ, the positional displacement amount Δz of the distance sensor 200 in the height direction, and the positional displacement amount in the horizontal direction) corresponding to the working radius R, and then perform the map generation process based on each of the acquired displacement amounts. The working radius R can be calculated, for example, based on the posture of the work attachment 15 measured by various sensors.

[0127] [Effects and Effects] According to this modified version, before executing the map generation process, the map generation unit 202b is made to perform pre-processing for each working radius R of the work attachment 15. This generates correction data D, which consists of the displacement angle θ (corresponding to the amount of angular displacement), the positional displacement amount Δz in the height direction, and the positional displacement amount Δy in the horizontal direction for each working radius R, and stores this data in the memory unit. As a result, when the map generation unit 202b executes the map generation process, each displacement amount can be acquired with high accuracy and quickly according to the working radius R of the work attachment 15. Therefore, the map generation unit 202b can generate high-precision map data regardless of changes in the working radius R of the work attachment 15.

[0128] (Embodiment 3) Figure 16 is a diagram corresponding to Figure 8 showing Embodiment 3, and Figure 17 is an explanatory diagram for explaining the contents of the angular displacement calculation process in Embodiment 3. This embodiment differs from Embodiment 1 in that it uses point cloud data of the main winding rope 28 when performing the angular displacement calculation process.

[0129] In this embodiment, first, the distance sensor 200 is positioned so that the hanging portion 28a (the portion that hangs vertically downward due to gravity) of the main winding rope 28 is included within its measurement range, and the controller 202 executes the process shown in Figure 16. In the following description, the same process as in Embodiment 1 will be omitted as appropriate.

[0130] Steps SD1 to SD2 perform the same processing as steps SA1 to SA2 of Embodiment 1.

[0131] In step SD3, the point cloud data acquired in step SD2 (i.e., point cloud data in the measurement coordinate system) is displayed on the touch panel 204a of the display device 204 along with the measurement coordinate system. In addition to this display, a message (not shown) prompting the user to select two points located at both ends of the hanging portion 28a of the main winding rope 28 from the point cloud data is displayed on the touch panel 204a.

[0132] In step SD4, after the display processing in step SD3, it is determined whether or not the selection signals (press signals) for the two points have been received from the touch panel 204a within a predetermined time. If the determination is NO, the process returns to step SD1; if the determination is YES, the process proceeds to step SD5.

[0133] In step SD5, the map generation unit 202b recognizes the positions of the two points on the touch panel 204a based on the selection signals (pressure signals) of the two points received from the touch panel 204a, and identifies the coordinate positions of the two points in the measurement coordinate system based on the recognized positions. Then, it calculates the angle between the line connecting the two points and the Z' axis in the Y'Z' plane (within the plane of Figure 17) as the first slip angle θ1, and calculates the angle between the line connecting the two points and the Z' axis in the X'Z' plane (within the vertical plane perpendicular to the plane of Figure 17) as the second slip angle θ2 (not shown). In this embodiment, the operator selects the two points, but this is not limited to this, and the map generation unit 202b may automatically select the two points based on image processing or the like. Furthermore, if there are multiple main winding ropes 28, the average values ​​of the first and second slip angles θ1 and θ2 calculated for each of the multiple straight lines connecting the two points at both ends of the hanging portion 28a of each main winding rope 28 may be calculated. Alternatively, the direction of the hanging portion 28a of the main winding rope 28 may be determined from the image position of the point sheave or hook around which the main winding rope 28 is wound, and the angles between the determined direction, the straight line, and the Z' axis may be calculated as the first and second slip angles θ1 and θ2.

[0134] If the determination in step SD1 is NO, step SD6 proceeds to perform the same processing as in step SA11 of Embodiment 1.

[0135] In step SD7, map data is generated by transforming the point cloud data acquired in step SD6 into a map coordinate system (XYZ coordinate system) using the following transformation matrix (6), which rotates the point cloud data by a first shift angle θ1 around the X' axis and a second shift angle θ2 around the Y' axis.

[0136]

number

[0137] In step SD8, the same process as in step SA13 of Embodiment 1 is performed.

[0138] [Effects and Effects] As described above, in this embodiment, the crane 100 is configured to suspend the load W via the main winding rope 28, and the distance sensor 200 is positioned so that the hanging portion 28a of the main winding rope 28 that hangs vertically downward due to gravity is included within its measurement range, and the angle displacement calculation process is a process that calculates the inclination angle of the hanging portion 28a with respect to the measurement axis K in the measurement coordinate system as the first displacement angle θ1 and the second displacement angle θ2 based on the point cloud data acquired in the pre-data acquisition process (step SD5).

[0139] With this configuration, the angular displacement (first displacement angle θ1 and second displacement angle θ2) between the Z' axis of the measurement coordinate system and the Z axis of the map coordinate system can be easily calculated without using dedicated measuring equipment. That is, since the hanging portion 28a of the main winding rope 28 extends in the vertical direction (same direction as the extension direction of the height axis of the ground coordinate system) due to gravity, the inclination angle of the measurement axis K with respect to this hanging portion 28a can be calculated in the map generation unit 202b, thereby calculating the inclination angle of the measurement axis K in the vertical direction. This inclination angle of the measurement axis K in the vertical direction is the inclination angle of the Z' axis of the measurement coordinate system with respect to the Z axis of the map coordinate system, and is equal to the angular displacement between the measurement coordinate system and the map coordinate system. Therefore, with this configuration, the angular displacement between the Z' axis of the measurement coordinate system and the Z axis of the map coordinate system can be easily calculated using the hanging portion 28a of the main winding rope 28 without having to perform the measurement work of the angular displacement using dedicated measuring equipment.

[0140] (Other embodiments) Although a map generation device according to an embodiment of the present invention has been described above, the present invention is not limited thereto, and for example, the following modified embodiments can be adopted.

[0141] (1) In each of the embodiments and modifications described above, the distance sensor 200 is attached to the jib 14, which is an example of a work member, but it is not limited to this, and may be attached to the boom 13, or to the arm of the shovel.

[0142] (2) In the above embodiments and modifications, LIDAR was given as an example of the distance sensor 200, but it is not limited to this, and the distance sensor 200 may be composed of any sensor, such as a stereo camera, a laser distance sensor, or an infrared distance sensor.

[0143] (3) In each of the embodiments and modifications described above, a crane 100 was given as an example of a work machine equipped with a map generation device 210, but it is not limited to this, and the work machine may be configured in any way, for example, a demolition machine, an aerial work platform, or an excavator. In Embodiment 3, a lifting rope (main hoisting rope 28 in Embodiment 3) is required, so it is preferable to use a crane 100 rather than an excavator, but it is not limited to this. The crane 100 does not necessarily have a jib 14 and struts 21, 22, and may have a configuration with only a boom 13 (so-called crane specification), or a configuration with only one strut and a jib 14 that does not luff (so-called fixed jib specification). Also, the boom 13 and jib 14 are not limited to a lattice structure, and may be a telescopic structure that can be extended and retracted by hydraulics or the like. Also, the lower traveling body 12 of the crane 100 does not necessarily have to travel by the rotation of crawlers, and may travel by the rotation of wheels (tires), for example. Alternatively, the crane 100 may be equipped with a fixed lower body instead of the lower traveling body 12.

[0144] (4) The present invention includes a map generation method that is realized by the processing performed by the controller 202 in each of the above embodiments and each modified example.

[0145] (5) The present invention includes any combination of the embodiments and modifications described above. [Explanation of symbols]

[0146] 11: Upper rotating body 12: Lower running body (main body) 13: Boom 14: Jibu 15: Work attachments 28: Main hoisting rope (suspension rope) 28a: hanging part 100: Crane (working machine) 200: Distance sensor 202: Controller 202b: Map generation unit 205: Tilt angle detection sensor 205a: Map generation unit 210: Map Generator A1: Selection points (multiple points) B1: Selection points (multiple points) CL: Center axis of rotation D: Correction data J: Reference site K:Measurement axis R: Working radius W: Suspended load Y1: Horizontal separation distance Y2: Design horizontal separation distance Z1: Sensor mounting height Z2: Design sensor mounting height Δy: Horizontal displacement Δz: Amount of displacement in the height direction θ: Angle of displacement (amount of angular displacement) θ1: First displacement angle (amount of angular displacement) θ2: Second displacement angle (amount of angular displacement)

Claims

1. A distance sensor is mounted on a work machine so that its measuring axis intersects the ground, and it acquires point cloud data including the position information of each point by measuring the distance to each point in a point cloud that defines the surface shape of the object to be measured, including the ground. The system includes a map generation unit that performs a map generation process to generate three-dimensional map data by converting the point cloud data acquired by the distance sensor from a measurement coordinate system where the height axis is a coordinate axis coaxial with the measurement axis of the distance sensor to a map coordinate system where the height axis is a coordinate axis extending vertically in real space. The map generation unit, Before executing the map generation process, the system performs preprocessing including a pre-data acquisition process that causes the distance sensor to acquire the point cloud data in advance, and an angle shift calculation process that calculates the angle of angle shift, which is the angle between the height axis of the measurement coordinate system and the height axis of the map coordinate system, based on the point cloud data. A map generation device configured to perform a coordinate rotation process in which, when executing the map generation process, the point cloud data acquired by the distance sensor after the preprocessing is rotated around the origin of the measurement coordinate system by the amount of the angular displacement, thereby converting it into the map coordinate system.

2. In the map generation device according to claim 1, The aforementioned angular displacement calculation process is a map generation device that calculates the angle of inclination of the ground defined by the point cloud data in the measurement coordinate system based on the positional information of multiple points corresponding to the ground from the point cloud data acquired in the prior data acquisition process, and calculates the difference between the calculated angle of inclination of the ground and the actual angle of inclination of the ground as the amount of angular displacement.

3. In the map generation apparatus according to claim 2, The aforementioned work machine is further equipped with a tilt angle detection sensor that detects the tilt angle with respect to the horizontal direction, The map generation unit is configured to perform the angle displacement calculation process by estimating the actual ground inclination angle based on the inclination angle detected by the inclination angle detection sensor, and calculating the difference between the calculated ground inclination angle in the measurement coordinate system and the estimated ground inclination angle as the amount of angle displacement.

4. In the map generation device according to claim 1, The aforementioned work machine is configured to suspend a load via a load suspension rope, The distance sensor is positioned such that the hanging portion of the load rope that hangs vertically downward due to gravity is included within a predetermined measurement range. The aforementioned angular displacement calculation process is a process that calculates the angle of inclination of the hanging portion with respect to the measurement axis in the measurement coordinate system as the amount of angular displacement, based on the point cloud data acquired in the prior data acquisition process, in a map generation device.

5. In the map generation device according to claim 2 or 4, The aforementioned preprocessing further includes a height displacement calculation process, The height displacement calculation process involves first converting the point cloud data acquired in the pre-data acquisition process into a map coordinate system by rotating it around the origin of the measurement coordinate system by the amount of the angular displacement, and then, based on the point cloud data converted into the map coordinate system, calculating the distance along the vertical direction from the ground to the mounting position of the distance sensor in the map coordinate system as the sensor mounting height, and calculating the difference between the calculated sensor mounting height and the predetermined design sensor mounting height of the distance sensor as the positional displacement in the height direction from the design mounting position of the distance sensor. The map generation device is configured such that, when executing the map generation process, the map generation unit corrects the coordinate information of the point cloud data, which has been converted to the map coordinate system by the coordinate rotation process, based on the amount of positional displacement in the height direction of the distance sensor calculated by the height displacement calculation process.

6. In the map generation device according to claim 5, The aforementioned work machine comprises a main body and a work member rotatably supported on the main body. The distance sensor is attached to the work member. The aforementioned preprocessing further includes a horizontal displacement calculation process, The horizontal displacement calculation process is a process that geometrically calculates the amount of horizontal displacement from the design mounting position of the distance sensor, based on the assumption that the cause of the displacement is the vertical deflection deformation of the work member, using the amount of displacement calculated in the height displacement calculation process. The map generation device is configured such that, when executing the map generation process, the map generation unit corrects the coordinate information of the point cloud data, which has been converted to the map coordinate system by the coordinate rotation process, based on the amount of horizontal positional displacement of the distance sensor calculated by the horizontal displacement calculation process.

7. In the map generation device according to claim 5, The aforementioned work machine has a reference part consisting of a predetermined surface or edge, The distance sensor is positioned such that the reference area is included within a predetermined measurement range. The aforementioned preprocessing further includes a horizontal displacement calculation process, The horizontal displacement calculation process involves first converting the point cloud data acquired in the pre-data acquisition process into a map coordinate system by rotating it around the origin of the measurement coordinate system by the amount of the angular displacement, then calculating the horizontal separation distance between the reference part and the mounting position of the distance sensor based on the point cloud data in the map coordinate system, and calculating the difference between the calculated horizontal separation distance and the horizontal separation distance between the reference part and the mounting position of the distance sensor in the design as the amount of horizontal displacement of the distance sensor from the design mounting position. The map generation unit is configured to correct the coordinate information of the point cloud data, which has been converted to the map coordinate system by the coordinate rotation process, based on the amount of horizontal positional displacement of the distance sensor calculated by the horizontal displacement calculation process, when executing the map generation process.

8. In the map generation device according to claim 6, The aforementioned work machine comprises a lower body, an upper slewing body supported on the lower body so as to be rotatable about a pivot axis extending vertically, and a work attachment including a base end and a tip end opposite to the base end, which are supported on the upper slewing body so as to be rotatable in the luffing direction. The distance sensor is attached to the tip of the work attachment. The aforementioned work attachment is configured to allow the working radius, which is the horizontal distance from the pivot axis to the tip, to be changed. The map generation unit is configured to generate correction data that associates each work radius with the amount of angular displacement, the amount of positional displacement in the height direction, and the amount of positional displacement in the horizontal direction for each work radius, by changing the working radius of the work attachment to one of a predetermined number of working radii before executing the map generation process, and by performing the pre-processing by the map generation unit for each work radius. The system further comprises a storage unit for storing the correction data generated by the map generation unit, The map generation device is configured such that, when executing the map generation process, it acquires the current working radius of the work attachment, acquires the amount of angular displacement, the amount of positional displacement in the height direction, and the amount of positional displacement in the horizontal direction corresponding to the working radius based on the correction data stored in the storage unit, and executes the map generation process based on the acquired amounts of displacement.

9. In the map generation apparatus according to claim 7, The aforementioned work machine comprises a lower body, an upper slewing body supported on the lower body so as to be rotatable about a pivot axis extending vertically, and a work attachment including a base end and a tip end opposite to the base end, which are supported on the upper slewing body so as to be rotatable in the luffing direction. The distance sensor is attached to the tip of the work attachment. The aforementioned work attachment is configured to allow the working radius, which is the horizontal distance from the pivot axis to the tip, to be changed. The map generation unit is configured to generate correction data that associates each work radius with the amount of angular displacement, the amount of positional displacement in the height direction, and the amount of positional displacement in the horizontal direction for each work radius, by changing the working radius of the work attachment to one of a predetermined number of working radii before executing the map generation process, and by performing the pre-processing by the map generation unit for each work radius. The system further comprises a storage unit for storing the correction data generated by the map generation unit, The map generation device is configured such that, when executing the map generation process, it acquires the current working radius of the work attachment, acquires the amount of angular displacement, the amount of positional displacement in the height direction, and the amount of positional displacement in the horizontal direction corresponding to the working radius based on the correction data stored in the storage unit, and executes the map generation process based on the acquired amounts of displacement.

10. In the map generation device according to any one of claims 1 to 4, The aforementioned work machine comprises a lower body, an upper slewing body supported on the lower body so as to be rotatable around a pivot axis extending vertically, and a work attachment including a base end and a tip end opposite to the base end, which are supported on the upper slewing body so as to be rotatable in the luffing direction. The distance sensor is a map generation device attached to the tip of the work attachment.

11. It is a work machine, A distance sensor is attached to the work machine so as to intersect the ground, and acquires positional information of each point in a point cloud that defines the surface shape of the object to be measured, including the ground, as point cloud data. The system includes a map generation unit that performs a map generation process to generate three-dimensional map data by converting the point cloud data acquired by the distance sensor from a measurement coordinate system where the height axis is a coordinate axis coaxial with the measurement axis of the distance sensor to a map coordinate system where the height axis is a coordinate axis extending vertically in real space. The map generation unit, Before executing the map generation process, the system performs preprocessing including a pre-data acquisition process that causes the distance sensor to acquire the point cloud data in advance, and an angle shift calculation process that calculates the amount of angular shift between the height axis of the measurement coordinate system and the height axis of the map coordinate system based on the point cloud data. The work machine is configured to perform a coordinate rotation process in which, when executing the map generation process, the point cloud data acquired by the distance sensor is rotated around the origin of the measurement coordinate system by the amount of the angular displacement, thereby converting it into a map coordinate system.

12. A point cloud data acquisition step involves attaching a distance sensor to a work machine so that its measurement axis intersects the ground, and using the distance sensor to measure the distance to each point in a point cloud that defines the surface shape of the object to be measured, including the ground, thereby acquiring point cloud data that includes the position information of each point. The system includes a map generation process that generates three-dimensional map data by converting the point cloud data acquired by the distance sensor from a measurement coordinate system where the height axis is a coordinate axis coaxial with the measurement axis of the distance sensor to a map coordinate system where the height axis is a coordinate axis extending vertically in real space. The map generation process includes a pre-processing step, The pre-processing step includes a pre-data acquisition step in which the distance sensor acquires the point cloud data in advance before executing the map generation process, and an angle shift calculation step in which the angle of angle shift, which is the angle between the height axis of the measurement coordinate system and the height axis of the map coordinate system, is calculated based on the point cloud data. In the map generation step, when executing the map generation process, a coordinate rotation process is performed to convert the point cloud data acquired by the distance sensor in the point cloud data acquisition step into the map coordinate system by rotating it around the origin of the measurement coordinate system by the amount of the angular displacement.

Images