Terrain recognition system and terrain recognition method

Abstract

According to the present invention, a processing circuit of a terrain recognition system is configured to: acquire ground surface height data indicating the ground surface height of each of a plurality of sub-areas included in an excavation target area; execute first update processing for updating the ground surface height of the sub-areas in the ground surface height data each time excavation by a construction machine is performed a set number of times, the first update processing being executed on the basis of point group data acquired from a distance measurement sensor; and execute second update processing for updating the ground surface height, of the sub-areas through which a bucket has passed, in the ground surface height data, the second update processing being executed on the basis of trajectory information indicating the movement trajectory of the bucket.

Description

Terrain recognition system and terrain recognition method

[0001] The present disclosure relates to a terrain recognition system and a terrain recognition method for a construction machine.

[0002] Patent Document 1 discloses an excavator that can recognize the current shape of the ground surface being worked on. The controller of the excavator includes a terrain database update unit and a ground shape information acquisition unit. The terrain database update unit can update the terrain database using the output of an imaging device that acquires images of the area around the excavator. The ground shape information acquisition unit acquires information about the current shape of the ground surface being excavated based on the terrain information updated by the terrain database update unit and past changes in the attitude of the excavation attachment.

[0003] Patent No. 7178885

[0004] In construction machinery, there is a demand for excavation work to be carried out while accurately recognizing the topography of the area to be excavated.

[0005] The present disclosure aims to provide a terrain recognition system and a terrain recognition method that can accurately recognize the terrain of an area to be excavated by a construction machine.

[0006] A terrain recognition system according to one aspect of the present disclosure is a terrain recognition system for a construction machine including a bucket for excavating soil and gravel in an excavation target area and a ranging sensor, for recognizing the terrain of the excavation target area, wherein the terrain recognition system includes a processing circuit, and the processing circuit is configured to acquire ground surface height data indicating the ground surface height of each of a plurality of sub-areas included in the excavation target area, and each time excavation by the construction machine is performed a set number of times, perform a first update process to update the ground surface height of the sub-area in the ground surface height data based on point cloud data acquired from the ranging sensor, and perform a second update process to update the ground surface height of the sub-area through which the bucket has passed in the ground surface height data based on trajectory information indicating the movement trajectory of the bucket.

[0007] A terrain recognition method according to one aspect of the present disclosure is a terrain recognition method for recognizing the terrain of an area to be excavated, for use with a construction machine including a bucket for excavating soil and gravel in the area to be excavated and a ranging sensor, the method acquiring ground surface height data indicating the ground surface height of each of a plurality of sub-areas included in the area to be excavated, and each time excavation is performed by the construction machine a set number of times, performing a first update process to update the ground surface height of the sub-area in the ground surface height data based on point cloud data acquired from the ranging sensor, and performing a second update process to update the ground surface height of the sub-area through which the bucket has passed in the ground surface height data based on trajectory information indicating the movement trajectory of the bucket.

[0008] According to one aspect of the present disclosure, the topography of an area to be excavated by a construction machine can be recognized with high accuracy.

[0009] Fig. 1 is a schematic side view of a hydraulic excavator, which is an example of a construction machine. Fig. 2 is a diagram showing a hydraulic circuit incorporated in the construction machine of Fig. 1. Fig. 3 is a schematic configuration diagram of a control system for a construction machine including a terrain recognition system according to a first embodiment. Fig. 4 is a flowchart showing the flow of processing by the control system. Fig. 5 is an example of a ground surface height map showing the ground surface height of an area to be excavated. Fig. 6 is a flowchart showing the flow of processing according to a modified example by the control system. Fig. 7 is a diagram explaining a terrain recognition system according to a second embodiment.

[0010] Hereinafter, an embodiment will be described with reference to the drawings.

[0011] <First embodiment> Fig. 1 shows a construction machine 1 in which a terrain recognition system of a first embodiment is used, and Fig. 3 shows a control system 4 for the construction machine 1 that includes the terrain recognition system. The construction machine 1 performs excavation work in an area to be excavated. The area to be excavated is an area of ​​the ground that is the target of work. In this embodiment, the construction machine 1 is a hydraulic excavator 10. However, the control system 4 may also be used in a construction machine 1 other than the hydraulic excavator 10, such as a wheel loader, as long as the construction machine 1 includes a bucket 16 for excavating earth and sand.

[0012] The construction machine 1 includes a running body 11 and a plurality of movable members 12 that constitute an articulated body rotatably supported on the running body 11. In other words, the movable members 12 are rotatably connected to each other, and the movable member 12 closest to the running body 11 is rotatably connected to the running body 11. In this embodiment, the running body 11 includes a pair of crawlers.

[0013] The bucket 16 is located at the tip of the articulated body. That is, the side of the traveling body 11 opposite to the bucket 16 is the base end side, and the bucket 16 side is the tip end side.

[0014] 2, the construction machine 1 further includes travel motors 31, 32 that respectively drive the pair of crawlers, and a plurality of hydraulic actuators 33 that respectively rotate the movable member 12. The travel motors 31, 32 and the hydraulic actuator 33, together with the pump device 21, form a hydraulic circuit 2. More specifically, the pump device 21 is connected to a valve unit 22 that includes a plurality of control valve devices 40, and the travel motors 31, 32 and the hydraulic actuator 33 are connected to this valve unit 22.

[0015] In this embodiment, the pump device 21 includes a variable displacement pump (a swash plate pump or a bent-axis pump) 21a with a variable tilt angle, and a regulator 21b that changes the tilt angle of the pump 21a. In this embodiment, the discharge flow rate of the pump device 21 is controlled by an electrical positive control system. However, the discharge flow rate of the pump device 21 may also be controlled by another system, such as a hydraulic negative control system.

[0016] In this embodiment, the construction machine 1 is a hydraulic excavator 10, and therefore the movable member 12 includes a swing body 13, a boom 14, an arm 15, and the above-mentioned bucket 16, as shown in Figure 1. The hydraulic actuator 33 includes a swing motor 34, a boom cylinder 35, an arm cylinder 36, and a bucket cylinder 37, as shown in Figure 2.

[0017] The swing motor 34 rotates the rotating unit 13 relative to the running unit 11 around a rotation axis Jsw that extends at the center of the running unit 11 in a direction perpendicular to the front-to-rear and width directions of the running unit 11. The boom cylinder 35 rotates the boom 14 relative to the rotating unit 13 around a rotation axis Jbm that extends at the base end of the boom 14 in the width direction of the rotating unit 13. The arm cylinder 36 rotates the arm 15 relative to the boom 14 around a rotation axis Jam that extends at the tip of the boom 14 in the width direction of the rotating unit 13. The bucket cylinder 37 rotates the bucket 16 relative to the arm 15 around a rotation axis Jbt that extends at the tip of the arm 15 in the width direction of the rotating unit 13.

[0018] The multiple control valve devices 40 include two travel motor control valve devices 41, a swing control valve device 42, a boom control valve device 43, an arm control valve device 44, and a bucket control valve device 45. The two travel motor control valve devices 41 control the flow of hydraulic oil supplied from the pump device 21 to the travel motors 31, 32, respectively. The swing control valve device 42 controls the flow of hydraulic oil supplied from the pump device 21 to the swing motor 34. The boom control valve device 43 controls the flow of hydraulic oil supplied from the pump device 21 to the boom cylinder 35. The arm control valve device 44 controls the flow of hydraulic oil supplied from the pump device 21 to the arm cylinder 36. The bucket control valve device 45 controls the flow of hydraulic oil supplied from the pump device 21 to the bucket cylinder 37.

[0019] 2, multiple control valve devices 40 are incorporated into one valve unit 22, but the valve unit 22 may be composed of multiple units, or multiple control valve devices 40 may be incorporated into multiple, mutually independent units. Furthermore, the configuration of the control valve device 40 is not particularly limited as long as it is capable of controlling the flow of hydraulic oil supplied to or discharged from the corresponding actuator. For example, the control valve device 40 may be an electromagnetic spool valve. Alternatively, the control valve device 40 may include a pilot-operated spool valve and an electromagnetic proportional valve that outputs pilot pressure to the pilot-operated spool valve.

[0020] 3, the control system 4 for the construction machine 1 includes a plurality of attitude angle sensors 5, a distance measurement sensor 6, a controller 7, and the plurality of control valve devices 40 and pump device 21 that are controlled by the controller 7. The plurality of attitude angle sensors 5, the distance measurement sensor 6, the plurality of control valve devices 40, and the pump device 21 are connected to the controller 7 by wire or wirelessly.

[0021] In addition, if the pump device 21 is controlled by a method other than the electrical positive control method, the pump device 21 does not need to be controlled by the controller 7, and the pump device 21 does not need to be connected to the controller 7.

[0022] The attitude angle sensor 5 detects the attitude of the construction machine 1 as attitude information. In this embodiment, the attitude angle sensor 5 includes a vehicle body attitude angle sensor 51, a swing attitude angle sensor 52, a boom attitude angle sensor 53, an arm attitude angle sensor 54, and a bucket attitude angle sensor 55. The vehicle body attitude angle sensor 51 detects the vehicle body attitude angle, which is the inclination angle of the traveling body 11 with respect to the horizontal plane. The swing attitude angle sensor 52 detects the swing attitude angle, which is the angle of the fore-and-aft direction of the rotating body 13 with respect to the fore-and-aft direction of the traveling body 11 on a plane perpendicular to the rotation axis Jsw. The boom attitude angle sensor 53 detects the boom attitude angle, which is the inclination angle of the boom 14 with respect to the horizontal plane. The arm attitude angle sensor 54 detects the arm attitude angle, which is the inclination angle of the arm 15 with respect to the horizontal plane. The bucket attitude angle sensor 55 detects the bucket attitude angle, which is the inclination angle of the bucket 16 with respect to the horizontal plane.

[0023] The ranging sensor 6 is used to measure the topography of the area to be excavated. The ranging sensor 6 measures the distance from the ranging sensor 6 to each point in the area to be excavated and acquires three-dimensional point cloud data of the surface of the area to be excavated. The point cloud data is a collection of point data indicating the three-dimensional coordinates of each position of the topography included in the measurement range (which may also be referred to as the field of view range) of the ranging sensor 6. The ranging sensor 6 is, for example, a LiDAR (Light Detection and Ranging) or a stereo camera.

[0024] The distance measurement sensor 6 is positioned so as to measure the terrain in front of the revolving body 13 of the construction machine 1. In this embodiment, the construction machine 1 is a hydraulic excavator 10, and therefore a cabin 17 including a driver's seat where an operator sits is mounted on the front left side of the revolving body 13. The distance measurement sensor 6 is attached to the front side of the roof of the cabin 17. If the area to be excavated is located in front of the revolving body 13, the measurement range of the distance measurement sensor 6 will include the area to be excavated.

[0025] The controller 7 includes a processing circuit 70. The processing circuit 70 generates a control command to be output to a controlled object based on the attitude information received from the plurality of attitude angle sensors 5 and the point cloud data received from the distance measurement sensor 6.

[0026] The processing circuit 70 includes a processor 71, a system memory 72, and a storage memory 73. The processor 71 may include a CPU. The system memory 72 may include a RAM. The storage memory 73 may include a hard disk, a flash memory, or a combination thereof. The storage memory 73 stores a program 73a.

[0027] The controller 7 may include at least one user interface 74. The user interface 74 may be located in the cockpit. For example, the user interface 74 includes an input interface and an output interface. For example, the input interface may be a touch panel, a steering wheel, a lever, a switch, or the like. For example, the output interface may be a display.

[0028] The controller 7 may include at least one communication interface 75. The communication interface 75 includes an interface that communicatively connects an external device to the controller 7 via a wired or wireless connection. The communication interface 75 may include an interface that communicatively connects to a communication network such as the Internet via a wired or wireless connection.

[0029] In this embodiment, an automatic excavation program is included in the programs 73a stored in the storage memory 73. The automatic excavation program is a program for causing the construction machine 1 to automatically perform excavation work in an excavation target area, and the automatic excavation program read from the storage memory 73 is executed by the processor 71, causing the processing circuitry 70 to execute the automatic excavation process.

[0030] In the automatic excavation processing of this embodiment, the construction machine 1 proceeds with excavation work in the excavation target area while recognizing, in a timely manner, the topography of the excavation target area, which may change due to excavation. That is, in this embodiment, the automatic excavation program includes a terrain recognition program for recognizing the topography of the excavation target area, and the controller 7 functions as a terrain recognition device.

[0031] 4 is a flowchart showing the flow of the automatic excavation process by the control system 4. The automatic excavation process is started when the area to be excavated has been determined and the relative positional relationship of the area to be excavated with respect to the construction machine 1 has been grasped by the processing circuitry 70.

[0032] For example, the area to be excavated may be determined in advance in the absolute coordinate system (XY coordinate system) of the construction site, in which case the construction machine 1 may be equipped with a position sensor for detecting the position of the construction machine 1 in the absolute coordinate system and a direction sensor for detecting the orientation of the construction machine 1 in the absolute coordinate system. For example, the construction machine 1 may be equipped with a GNSS compass. In other words, by determining the position and orientation of the construction machine 1 in the absolute coordinate system, it is possible to determine the positional relationship of the construction machine 1 with respect to the area to be excavated in the absolute coordinate system.

[0033] Alternatively, for example, the excavation target area may be set as an area that can be excavated without moving the construction machine 1. In other words, the excavation target area may be defined in a relative coordinate system with respect to the construction machine 1.

[0034] When the automatic excavation process is started, the processing circuit 70 first determines whether the excavation to be performed is the first excavation in the excavation target area (step S1).

[0035] If it is determined that the excavation to be carried out is the first time (step S1: Yes), the processing circuit 70 controls each control object (e.g., the rotation control valve device 42, the boom control valve device 43, the arm control valve device 44, the bucket control valve device 45, and the pump device 21) to change the posture of the construction machine 1 to a predetermined posture for distance measurement (step S2).

[0036] Specifically, the attitude for distance measurement is an attitude that prevents as much of the construction machine 1 as possible from entering the measurement range of the distance sensor 6 (for example, the scanning range of the LiDAR if the distance sensor 6 is a LiDAR). In other words, step S2 is a step for reducing the area of ​​the excavation target area that is a blind spot for the distance sensor 6 due to the boom 14, arm 15, and bucket 16. For example, the attitude for distance measurement can be defined in advance by the swing attitude angle, boom attitude angle, arm attitude angle, and bucket attitude angle. For example, when the construction machine 1 is in the attitude for distance measurement, the position of the bucket 16 can be located above the distance sensor 6.

[0037] After changing the attitude of the construction machine 1 to the attitude for distance measurement, the processing circuit 70 executes a first terrain recognition process (step S3). The first terrain recognition process is a process for recognizing the terrain of the area to be excavated using the distance measurement sensor 6. In this embodiment, in the first terrain recognition process and the second terrain recognition process described below, recognizing the terrain of the area to be excavated means storing ground surface height data indicating the ground surface height of each of the multiple sub-areas that make up the area to be excavated or updating the ground surface height data. The ground surface height data is stored in, for example, the storage memory 73.

[0038] The ground surface heights of the multiple sub-areas will be described with reference to FIG. 5. FIG. 5 is an example of a ground surface height map showing the ground surface height of the excavation target area R1. In FIG. 5, the range of the excavation target area R1 is defined on an XY plane parallel to the horizontal plane. As shown in FIG. 5, the excavation target area R1 is divided into multiple sub-areas R2. The type of hatching in each sub-area R2 indicates the ground surface height of each sub-area R2. The ground surface height data for each sub-area R2 is stored in association with the position information of the corresponding sub-area R2.

[0039] 5, the excavation target area R1 is shown as a rectangular surface parallel to the horizontal plane, and the sub-area R2 is defined as a square, but the shapes of the excavation target area R1 and the sub-areas R2 are not limited to this. For example, the excavation target area R1 may be trapezoidal or fan-shaped. The number of sub-areas R2 included in the excavation target area R1 and the ratio of the size of the sub-areas R2 to the size of the excavation target area R1 may also be set appropriately.

[0040] In the first terrain recognition process of this embodiment, the processing circuitry 70 first sends a command to the ranging sensor 6 to start measurement. After the ranging sensor 6 completes measurement, the processing circuitry 70 receives three-dimensional point cloud data from the ranging sensor 6. The processing circuitry 70 determines which sub-area R2 contains the X and Y coordinates of each point data in the acquired three-dimensional point cloud data. The processing circuitry 70 then calculates the ground level of the sub-area R2 from the Z coordinates of the point data contained in the sub-area R2.

[0041] For example, if a certain sub-area R2 includes only one piece of point data, the processing circuitry 70 sets the Z coordinate of the point data as the ground level for the sub-area R2. For example, if a certain sub-area R2 includes multiple pieces of point data, the processing circuitry 70 calculates one piece of ground level from the Z coordinates of the multiple pieces of point data by a predetermined calculation. For example, the processing circuitry 70 may calculate the average value of the Z coordinates of the multiple pieces of point data as the ground level, or may remove outliers from the Z coordinates of the multiple pieces of point data and calculate the ground level from the remaining Z coordinates.

[0042] A subarea R2 may not include a single point data. For example, a subarea R2 that is in the blind spot of the ranging sensor 6 due to at least one of the boom 14, the arm 15, and the bucket 16 may not include a single point data. Furthermore, if there is a mound of earth and sand within the excavation target region R1, a subarea R2 that is in the blind spot of the ranging sensor 6 due to the mound may not include a single point data. When there is a subarea R2 where the ranging sensor 6 could not measure the distance (hereinafter referred to as an unmeasurable area), the processing circuit 70 may estimate the ground level of the unmeasurable area from the ground level of the subarea R2 surrounding the unmeasurable area. For example, the ground level of the unmeasurable area may be estimated by a known interpolation method using the ground level of the subareas R2 surrounding the unmeasurable area, or by averaging the ground level of multiple subareas R2 surrounding the unmeasurable area.

[0043] In this way, the processing circuit 70 acquires ground surface elevation data indicating the ground surface elevation of each sub-area R2 of the excavation target area R1 and stores it in the memory 73.

[0044] Next, the processing circuit 70 determines whether the number of excavations since the previous first terrain recognition process has reached a set number (step S4). More specifically, during the automatic excavation process, the processing circuit 70 counts the number of excavations k in steps S5 and S8 described below. In step S4, the processing circuit 70 determines whether the number of excavations k has reached a set number. When the first terrain recognition process is executed in step S7 described below, the processing circuit 70 resets the number of excavations k to its initial value of zero.

[0045] If it is determined that the number of excavation operations since the previous first terrain recognition process has reached the set number (step S4: Yes), the processing circuit 70 controls each control object (e.g., the swing control valve device 42, the boom control valve device 43, the arm control valve device 44, the bucket control valve device 45, and the pump device 21) to excavate soil and sand in the excavation target area R1 (step S5). In step S5, for example, the processing circuit 70 determines which location in the excavation target area R1 to excavate soil and sand based on the ground surface height data, and controls the control object to excavate soil and sand in the determined location.

[0046] The processing circuit 70 then controls the control valve devices 40 and the pump device 21 to change the attitude of the construction machine 1 to an attitude for distance measurement (step S6), and then the processing circuit 70 executes a first terrain recognition process (step S7). Steps S6 and S7 are similar to steps S2 and S3, respectively, and therefore will not be described here.

[0047] In step S4, if it is determined that the number of excavations since the previous first terrain recognition process has not reached the set number (step S4: No), the processing circuit 70 controls the control object to excavate soil and sand in the excavation target area R1 (step S8).

[0048] At least in step S8, processing circuitry 70 stores information necessary to calculate the trajectory of the tip of operating bucket 16. For example, processing circuitry 70 stores time-series data of detection values ​​of a plurality of attitude angle sensors 5 while bucket 16 moves for excavation.

[0049] After step S8, the processing circuit 70 executes a second terrain recognition process (step S9). The second terrain recognition process is a process for recognizing the terrain of the excavation target area based on the trajectory of the tip of the bucket 16 during the excavation in step S8.

[0050] Specifically, in the second terrain recognition process, the processing circuitry 70 calculates the movement trajectory of the tip of the bucket 16 from time-series data of detection values ​​from the multiple attitude angle sensors 5 while the bucket 16 is moving during excavation, and stores the calculated trajectory as trajectory information. For example, the movement trajectory of the tip of the bucket 16 may be time-series data of the position coordinates of two points, the right and left ends, of the tip-side edge of the bucket 16 during the operation of the construction machine 1 in step S8. Thereafter, the processing circuitry 70 identifies the sub-area R2 through which the bucket 16 passed during the excavation in step S8, from the trajectory information and the ground elevation data stored in memory 73, and updates the ground elevation of the identified sub-area R2 to the elevation of the tip of the bucket 16 when it passed through sub-area R2.

[0051] An example of the second terrain recognition process will be described below. However, the method of calculating the movement trajectory of the tip of the bucket 16, the method of identifying the sub-area R2 through which the bucket 16 has passed, and the method of updating the ground surface height of the identified sub-area R2 are not limited to the second terrain recognition process described below.

[0052] First, the processing circuit 70 calculates, as trajectory information, time-series data of the position coordinates of each point: a first point at the right end of the tip of the bucket 16, a second point at the left end of the tip of the bucket 16, and a third point on the opening surface of the bucket 16, from time-series data of the detection values ​​of the multiple attitude angle sensors 5 while the bucket 16 is moving during excavation. For example, the third point is a point located in the center of the edge on the base end side of the bucket 16. Thereafter, the processing circuit 70 treats the first point, second point, and third point as one set and performs the following processing for each set.

[0053] The processing circuit 70 sets a virtual triangle with the first, second, and third points as its vertices and projects the virtual triangle onto the XY plane. The processing circuit 70 identifies a sub-area R2 that overlaps the projected triangle on the XY plane by a certain amount. For example, the processing circuit 70 compares the center of gravity of the projected triangle with the center of gravity of each sub-area R2 and identifies the sub-area R2 whose center of gravity is located within the projected triangle. The processing circuit 70 extracts the height (Z coordinate) of a point on the virtual triangle with the first, second, and third points as its vertices, based on the XY coordinates of the center of gravity of the identified sub-area R2, and compares the extracted height with the ground level of the sub-area R2 stored in memory 73. If the processing circuit 70 determines that the extracted height is smaller than the stored ground level of the sub-area R2, it updates the stored ground level of the sub-area R2 to the extracted height. If the processing circuit 70 determines that the extracted height is equal to or greater than the ground surface height of the sub-area R2 stored in the memory 73, it does not update the ground surface height of the sub-area R2 stored in the memory 73 but maintains it.

[0054] The processing circuit 70 sequentially performs the above-mentioned processing on the virtual triangle extracted from the time series data during the excavation operation on multiple virtual triangles extracted from the time series data corresponding to the excavation operation, and then terminates the second terrain recognition processing.

[0055] After steps S7 and S9, the process returns to step S1. In this way, each time excavation is performed, either the first terrain recognition process in step S7 or the second terrain recognition process in step S9 is executed, and the ground surface height data stored in memory 73 is updated. The first terrain recognition process in step S7 corresponds to the first update process, and the second terrain recognition process in step S9 corresponds to the second update process.

[0056] The above-described automatic excavation process is an example. For example, instead of executing steps S5 and S8 after the determination in step S4, the processing circuitry 70 may control the control target to excavate the soil in the excavation target region R1 before the determination in step S4.

[0057] As described above, in this embodiment, the second terrain recognition process updates the ground surface height of the sub-area R2 in the ground surface height data from the movement trajectory of the bucket 16, so that the ground surface height of the excavation target area R1, which changes each time excavation is performed, can be recognized in real time.

[0058] Furthermore, in this embodiment, each time the construction machine 1 performs excavation a set number of times, a first terrain recognition process is executed to update the ground surface height of the sub-area R2 based on the point cloud data acquired from the ranging sensor 6. This makes it possible to eliminate, at an appropriate timing, the discrepancy between the ground surface height of the sub-area R2 recognized in the second terrain recognition process and the actual ground surface height of the sub-area. This allows the excavation work to proceed while accurately recognizing the ground surface height of the area to be excavated.

[0059] Furthermore, in order to perform the first terrain recognition process, it is necessary to change the posture of the construction machine 1 to a posture for distance measurement, and it also takes time to perform measurements with the distance measurement sensor 6. However, in this embodiment, the first terrain recognition process is limited to each time a set number of excavations are performed by the construction machine 1, so excavation work can be carried out efficiently.

[0060] (Processing according to a modified example) Figure 6 is a flowchart showing the flow of processing according to a modified example by the control system 4. In the processing shown in Figure 4, either the first terrain recognition processing or the second terrain recognition processing is executed each time excavation is performed, but in the processing shown in Figure 6, the second terrain recognition processing is always executed each time excavation is performed.

[0061] Steps T1, T2, and T3 shown in Fig. 6 are the same as steps S1, S2, and S3 shown in Fig. 4, respectively, and therefore will not be described here. After step T3, the processing circuit 70 controls the control object to excavate earth and sand in the excavation target area (step T4), and then executes a second terrain recognition process (step T5). Steps T4 and T5 shown in Fig. 6 are the same as steps S8 and S9 shown in Fig. 4, respectively, and therefore will not be described here.

[0062] After step T5, the processing circuit 70 determines whether the number of excavations since the previous first terrain recognition process has reached the set number (step T6). If it is determined that the number of excavations since the previous first terrain recognition process has reached the set number (step T6: Yes), the processing circuit 70 controls the control target to change the attitude of the construction machine 1 to the attitude for distance measurement (step T7), and then executes the first terrain recognition process (step T8). After step T8, or if it is determined in step T6 that the number of excavations since the previous first terrain recognition process has not reached the set number (step T6: No), the processing circuit 70 returns to step T1. Steps T6, T7, and T8 shown in FIG. 6 are similar to steps S4, S6, and S7 shown in FIG. 4, respectively, and therefore will not be described here. The first terrain recognition process in step T8 corresponds to the first update process, and the second terrain recognition process in step T5 corresponds to the second update process.

[0063] <Second embodiment> Figure 7 is a diagram illustrating a terrain recognition system 100 according to a second embodiment. The terrain recognition system 100 includes a plurality of attitude angle sensors 5 and distance measurement sensors 6 included in the construction machine 1, and a terrain recognition device 8 that is external equipment of the construction machine 1. The construction machine 1 is the same as that described in the first embodiment, so a description thereof will be omitted. In the first embodiment, the first terrain recognition process and the second terrain recognition process were executed by the controller 7 of the construction machine 1, but in the second embodiment, the first terrain recognition process and the second terrain recognition process are executed by the terrain recognition device 8.

[0064] The terrain recognition device 8 is disposed outside the construction machine 1. The terrain recognition device 8 is configured to be able to communicate with the controller 7 of the construction machine 1. The terrain recognition device 8 may be, for example, a cloud server.

[0065] The terrain recognition device 8 includes a processing circuit 80. The processing circuit 80 executes processing for recognizing the terrain of the area to be excavated based on information received from the construction machine 1.

[0066] The processing circuit 80 includes a processor 81, a system memory 82, and a storage memory 83. The processor 81 may include a CPU. The system memory 82 may include a RAM. The storage memory 83 may include a hard disk, a flash memory, or a combination thereof. The storage memory 83 stores a program 83a. In this embodiment, the program 83a includes a terrain recognition program for recognizing the terrain of the area to be excavated.

[0067] The terrain recognition device 8 may include at least one user interface 84. For example, the user interface 84 includes an input interface and an output interface. For example, the input interface may be a touch panel, a keyboard, a mouse, a microphone, etc. For example, the output interface may be a display.

[0068] The terrain recognition device 8 includes at least one communication interface 85. The communication interface 85 is an interface that is communicatively connected to the controller 7 of the construction machine 1. The communication interface 85 may be communicatively connected directly to the controller 7, or may be communicatively connected via a communication network such as the Internet.

[0069] The terrain recognition device 8 receives from the construction machine 1 the attitude information obtained by the attitude angle sensor 5, the point cloud data obtained by the distance measurement sensor 6, and excavation information indicating whether or not excavation has been performed in the excavation target area. The excavation information may be information indicating the number of excavations.

[0070] When the construction machine 1 starts excavating the excavation target area, the processing circuit 80 executes the following processing, similar to the processing shown in FIG. 4 described in the first embodiment.

[0071] For example, the processing circuit 80 determines whether or not this is the first excavation in the excavation target area based on the excavation information received from the construction machine 1 (step S1). If it is determined that the excavation to be performed is the first (step S1: Yes), the processing circuit 80 sends a command to the controller 7 to change the attitude of the construction machine 1 to a predetermined attitude for distance measurement (step S2). The processing circuit 80 also sends a command to the controller 7 requesting point cloud data obtained by the distance measurement sensor 6, and then executes a first terrain recognition process based on the point cloud data received from the controller 7 (step S3). In this way, the processing circuit 80 obtains ground surface elevation data indicating the ground surface elevation of each subarea R2 in the excavation target area R1 and stores the data in the memory 83.

[0072] Next, the processing circuit 80 determines whether the number of excavation operations since the previous first terrain recognition process has reached a set number of times (step S4).

[0073] If it is determined that the number of excavations since the previous first terrain recognition process has reached the set number (step S4: Yes), the processing circuit 80 receives excavation information that excavation has been performed in the excavation target area (step S5), and then performs processing similar to steps S2 and S3 described above (steps S6, S7).

[0074] If it is determined in step S4 that the number of excavation operations since the previous first terrain recognition process has not reached the set number of times (step S4: No), the processing circuitry 80 receives excavation information indicating that excavation has been performed in the excavation target area, as well as trajectory information indicating the movement trajectory of the tip of the bucket 16 or information required to calculate the movement trajectory (such as attitude information) (step S8). Thereafter, the processing circuitry 80 executes a second terrain recognition process based on the movement trajectory (step S9).

[0075] After steps S7 and S9, the process returns to step S1. In this way, the ground surface height data stored in the memory 83 is updated each time excavation is performed. When updating the ground surface height data in steps S7 and S9, the ground surface height data before the update does not need to be deleted, but may be stored as past ground surface height data. In other words, ground surface height data that changes during excavation work may be stored in a database on a cloud server, for example. The terrain recognition device 8 may send the ground surface height data to the controller 7 of the construction machine 1 each time the ground surface height data is updated. Furthermore, in this embodiment, a process similar to the process shown in FIG. 6 relating to the modified example can also be applied.

[0076] According to this embodiment, the terrain recognition process is executed by an external device of the construction machine 1, so the amount of calculations in the controller 7 of the construction machine 1 can be reduced.

[0077] The terrain recognition device 8 may be configured by a plurality of devices that are independent of each other. The terrain recognition device 8 may include a server and a user terminal that can be connected to the server for communication.

[0078] Other Embodiments The present disclosure is not limited to the above-described embodiments, and the configurations thereof may be changed, added, or deleted.

[0079] For example, the traveling body 11 may include a plurality of wheels instead of a pair of crawlers. In this case, the hydraulic circuit 2 may not include the traveling motors 31 and 32, and the wheels may be driven by an engine or an electric motor.

[0080] In the first and second embodiments, the program executed by the processing circuit was an automatic excavation program for causing the construction machine 1 to perform excavation work in an area to be excavated by automatic operation, but the processing circuit may execute only a terrain recognition program for recognizing the terrain of the area to be excavated, and the excavation operation by the construction machine 1 may be performed in response to manual operation by an operator. The operator may operate the construction machine 1 from inside the construction machine 1, or may operate it remotely from outside the construction machine 1.

[0081] For example, the operation of the construction machine 1 in steps S2, S5, S6, and S8 in Fig. 4 and steps T2, T4, and T8 in Fig. 6 may be controlled in response to manual operation by the operator. When the attitude of the construction machine 1 is changed to an attitude for distance measurement by the operator's operation, the attitude for distance measurement does not have to be a predetermined attitude, and may be an attitude determined by the operator's judgment.

[0082] The processing circuit may also output the ground surface height data to a display included in the user interface 74 or the user interface 84. In this case, a ground surface height map such as that shown in Fig. 5 may be displayed on the display. For example, when an excavation operation is performed by the construction machine 1 in response to operation by the operator, the operator can operate the construction machine 1 while grasping the topography of the area to be excavated in detail from the ground surface height data displayed on the display.

[0083] The set number of times may be a variable value. In this case, the processing circuitry may be configured to set the set number of times based on set number information input by the user via the user interface 74, 84, etc.

[0084] Alternatively, the processing circuit may be configured to acquire excavation status information indicating the excavation status of the construction machine 1, and set the set number of times based on the acquired excavation status information. The excavation status information may be, for example, soil information indicating the type and condition of the soil in the area to be excavated. In this case, the construction machine 1 may be equipped with a sensor that detects soil information, and the processing circuit may acquire the soil information from the sensor. Alternatively, the soil information may be information input by a user via a user interface.

[0085] The excavation condition information may be, for example, weather information indicating the weather at the time of excavation or the weather before excavation. In this case, the construction machine 1 may receive the weather information from a weather center. Alternatively, the weather information may be information input by the user via a user interface.

[0086] The processing circuit may be configured to, after executing the first update process, determine whether a deviation between the ground surface height indicated by the ground surface height data before the update and the ground surface height indicated by the ground surface height data after the update is equal to or greater than a predetermined value, and if it determines that the deviation is equal to or greater than the predetermined value, change the set number of times to be smaller than the set number of times before the update. In this case, the processing circuit may sum the deviations for all subareas in the excavation target area and determine whether the sum of the deviations is equal to or greater than a predetermined value. Alternatively, the processing circuit may determine whether the largest deviation among the deviations for all subareas in the excavation target area is equal to or greater than a predetermined value.

[0087] As described above, the above embodiments have been described as examples of the technology disclosed in this application. However, the technology of the present disclosure is not limited to these and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate. Furthermore, the components described in the above embodiments can be combined to create new embodiments. For example, some configurations or methods in one embodiment may be applied to other embodiments, and some configurations in an embodiment may be separated and arbitrarily extracted from other configurations in that embodiment. Furthermore, the components described in the accompanying drawings and detailed description include not only components essential for solving the problem, but also components that are not essential for solving the problem, and are used to illustrate the technology. Two blocks shown in a sequential order in a flowchart may be executed simultaneously or in reverse order, depending on the circumstances.

[0088] The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, special-purpose processors, integrated circuits, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. Processors are considered processing circuits or circuits because they include transistors and other circuitry. In this disclosure, a circuit, unit, or means is hardware that performs the recited functions or hardware that is programmed to perform the recited functions. The hardware may be hardware disclosed herein or other known hardware that is programmed or configured to perform the recited functions. Where the hardware is a processor, which is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or processor.

[0089] The program disclosed herein may be stored in a computer-readable storage medium. The storage medium is a non-transitory, tangible medium. The storage medium may be built into or external to a computer (e.g., a mobile information terminal, a personal computer, a server, etc.). The storage medium may include RAM, ROM, EEPROM, storage, etc., and may be, for example, a hard disk, a flash memory, an optical disk, etc. The program stored in the storage medium may be executed on a computer to which the storage medium is directly connected, or on a computer connected to the storage medium via a communication network (e.g., the Internet).

[0090] Each of the following aspects is a disclosure of a preferred embodiment.

[0091] [Aspect 1] A terrain recognition system for recognizing the terrain of an area to be excavated, for use with a construction machine including a bucket for excavating soil and sand in the area to be excavated, and a ranging sensor, wherein the terrain recognition system includes a processing circuit, and the processing circuit is configured to: acquire ground surface height data indicating the ground surface height of each of a plurality of sub-areas included in the area to be excavated; execute a first update process to update the ground surface height of the sub-area in the ground surface height data based on point cloud data acquired from the ranging sensor each time excavation by the construction machine is performed a set number of times; and execute a second update process to update the ground surface height of the sub-area through which the bucket has passed in the ground surface height data based on trajectory information indicating the movement trajectory of the bucket.

[0092] According to the above configuration, the second update process updates the ground surface height of the sub-area in the ground surface height data from the bucket movement trajectory, making it possible to recognize in real time the ground surface height of the excavation area, which changes with each excavation. Furthermore, according to the above configuration, the first update process is executed each time the construction machine performs a set number of excavations, updating the ground surface height of the sub-area based on the point cloud data acquired from the ranging sensor. Therefore, it is possible to eliminate, at an appropriate time, the discrepancy between the ground surface height of the sub-area recognized in the second update process and the actual ground surface height of the sub-area. Therefore, it is possible to proceed with excavation work while accurately recognizing the ground surface height of the excavation area.

[0093] [Aspect 2] The terrain recognition system according to Aspect 1, wherein the processing circuit is configured to: determine whether the number of excavations by the construction machine since the previous execution of the first update process has reached the set number of times each time the construction machine performs excavation; execute the first update process if it is determined that the number of excavations has reached the set number of times; and execute the second update process if it is determined that the number of excavations has not reached the set number of times.

[0094] [Aspect 3] The terrain recognition system according to aspect 1, wherein the processing circuit is configured to execute the second update process each time excavation is performed by the construction machine.

[0095] [Aspect 4] The terrain recognition system according to any one of Aspects 1 to 3, wherein the processing circuit is configured to set the set number of times based on set number information input by a user via a user interface.

[0096] According to the above configuration, the timing of executing the first update process can be adjusted at the discretion of the user depending on the situation.

[0097] [Aspect 5] The terrain recognition system according to any one of Aspects 1 to 4, wherein the processing circuit is configured to acquire excavation status information indicating an excavation status of the construction machine, and set the set number of times based on the acquired excavation status information.

[0098] According to the above configuration, the number of times can be adjusted to suit the excavation conditions.

[0099] [Aspect 6] The terrain recognition system according to any one of Aspects 1 to 5, wherein the processing circuit is configured to, after executing the first update process, determine whether or not a deviation between the ground surface height indicated by the ground surface height data before the update and the ground surface height indicated by the ground surface height data after the update is equal to or greater than a predetermined value, and if it determines that the deviation is equal to or greater than the predetermined value, change the set number of times so that it is smaller than the set number of times before the update.

[0100] According to this configuration, the deviation of the ground surface height data before and after the update by the first update process can be kept small, so that the ground surface height data can be maintained in a highly accurate state.

[0101] [Aspect 7] A terrain recognition method for recognizing the terrain of an area to be excavated, for use with a construction machine including a bucket for excavating soil and sand in the area to be excavated and a ranging sensor, the method comprising: acquiring ground surface height data indicating the ground surface height of each of a plurality of sub-areas included in the area to be excavated; performing a first update process to update the ground surface height of the sub-area in the ground surface height data based on point cloud data acquired from the ranging sensor each time excavation by the construction machine is performed a set number of times; and performing a second update process to update the ground surface height of the sub-area through which the bucket has passed in the ground surface height data based on trajectory information indicating the movement trajectory of the bucket.

[0102] According to the above method, the second update process updates the ground surface height of the sub-area in the ground surface height data from the bucket movement trajectory, making it possible to recognize in real time the ground surface height of the excavation area, which changes with each excavation. Furthermore, according to the above method, the first update process is executed each time the construction machine performs a set number of excavations, updating the ground surface height of the sub-area based on the point cloud data acquired from the ranging sensor. Therefore, it is possible to eliminate, at an appropriate time, the discrepancy between the ground surface height of the sub-area recognized in the second update process and the actual ground surface height of the sub-area. Therefore, it is possible to proceed with excavation work while accurately recognizing the ground surface height of the excavation area.

[0103] REFERENCE SIGNS LIST 1: Construction machine 4: Control system 5: Attitude angle sensor 6: Distance measurement sensor 10: Hydraulic excavator 13: Swing body 14: Boom 15: Arm 16: Bucket 21: Pump device 40: Control valve device 70, 80: Processing circuit 74, 84: User interface 100: Terrain recognition system

Claims

1. A terrain recognition system for a construction machine including a bucket for excavating soil and sand in an area to be excavated, and for recognizing the terrain of the area to be excavated, the terrain recognition system comprising a processing circuit, the processing circuit being configured to: acquire ground surface height data indicating the ground surface height of each of a plurality of sub-areas included in the area to be excavated, execute a first update process to update the ground surface height of the sub-area in the ground surface height data based on point cloud data acquired from the ranging sensor each time excavation by the construction machine is performed a set number of times, and execute a second update process to update the ground surface height of the sub-area through which the bucket has passed in the ground surface height data based on trajectory information indicating the movement trajectory of the bucket.

2. The terrain recognition system of claim 1, wherein the processing circuit is configured to: determine whether the number of excavations by the construction machine since the previous execution of the first update process has reached the set number each time the construction machine performs excavation; execute the first update process if it is determined that the number of excavations has reached the set number; and execute the second update process if it is determined that the number of excavations has not reached the set number.

3. The terrain recognition system of claim 1, wherein the processing circuitry is configured to execute the second update process each time excavation is performed by the construction machine.

4. A terrain recognition system according to any one of claims 1 to 3, wherein the processing circuit is configured to set the set number of times based on set number information input by a user via a user interface.

5. A terrain recognition system as described in any one of claims 1 to 3, wherein the processing circuit is configured to acquire excavation status information indicating the excavation status of the construction machine, and to set the set number of times based on the acquired excavation status information.

6. A terrain recognition system as described in any one of claims 1 to 3, wherein the processing circuit is configured to determine whether or not a deviation between the ground surface height indicated by the ground surface height data before the update and the ground surface height indicated by the ground surface height data after the update is equal to or greater than a predetermined value after executing the first update process, and if it determines that the deviation is equal to or greater than the predetermined value, to change the set number of times so that it is smaller than the set number of times before the update.

7. A terrain recognition method for recognizing the terrain of an area to be excavated, for use with a construction machine including a bucket for excavating soil and sand in the area to be excavated, and a distance measurement sensor, comprising: acquiring ground surface height data indicating the ground surface height of each of a plurality of sub-areas included in the area to be excavated; performing a first update process to update the ground surface height of the sub-area in the ground surface height data based on point cloud data acquired from the distance measurement sensor each time excavation by the construction machine is performed a set number of times; and performing a second update process to update the ground surface height of the sub-area through which the bucket has passed in the ground surface height data based on trajectory information indicating the movement trajectory of the bucket.

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