JP7779783B2 - hydraulic excavator - Google Patents

Description

The present invention relates to a hydraulic excavator.

When developing land with a hydraulic excavator, skill is required to operate the front working equipment to efficiently and accurately form the designed terrain (target terrain). Therefore, hydraulic excavators are sometimes equipped with a so-called machine guidance (MG) function that guides operation so that even operators with little experience in operating hydraulic excavators can work accurately and efficiently. One type of MG uses a rangefinder such as a laser scanner to scan the ground surface of the current terrain (present terrain) being developed by the front working equipment, and displays the measurement data of the present terrain along with the designed terrain data on a monitor (Patent Document 1).

International Publication No. 2019/175917

The current terrain during construction is not necessarily monotonous, and may be undulating from time to time. In this case, the laser light emitted from the rangefinder may be blocked by the ground surface in front, resulting in areas not being illuminated. When there is an obstacle blocking the laser light like this, it can be difficult to determine whether the measurement data displayed on the monitor truly represents the current terrain. In such situations, the operator must visually compare the measurement data displayed on the monitor with the current terrain during construction to determine the true current terrain while working, which reduces work efficiency.

The object of the present invention is to provide a hydraulic excavator that allows areas where the current topography has not been measured to be checked on a monitor, thereby improving work efficiency.

In order to achieve the above object, the present invention provides a hydraulic excavator comprising a vehicle body having a driver's cab, a front work implement attached to the vehicle body, a monitor provided in the driver's cab, a rangefinder that measures distances to a plurality of rangefinder points on the current terrain around the vehicle body, and a controller that divides the periphery of the vehicle body into a plurality of meshes and displays measurement data of the current terrain based on the output of the rangefinder on the monitor for each of the meshes, wherein the controller calculates horizontal coordinates of the measured rangefinder points based on the output of the rangefinder, calculates the horizontal interval between each of the plurality of rangefinder points and adjacent rangefinders, and displays height data calculated based on the output of the rangefinder on the monitor as measurement data of the current terrain for each of the meshes for areas where the horizontal interval between adjacent rangefinder points is equal to or less than a set interval set based on the size of the mesh, and displays on the monitor meshes where no rangefinder points exist as unmeasurable areas where measurement is not possible, for areas where the horizontal interval between adjacent rangefinder points is greater than the set interval.

This invention allows areas where the current topography has not been measured to be checked on the monitor, thereby improving work efficiency.

FIG. 1 is a side view showing the overall structure of a hydraulic excavator according to a first embodiment of the present invention. Functional block diagram of a controller provided in a hydraulic excavator according to a first embodiment of the present invention. FIG. 1 is a schematic diagram illustrating an example of how the current topography is measured by a distance meter in the hydraulic excavator according to the first embodiment of the present invention. 1 is a diagram showing an example of a guidance screen displayed on a monitor provided in the hydraulic excavator according to the first embodiment of the present invention (a display example of height data of the designed terrain). 1 is a diagram showing an example of a guidance screen displayed on a monitor provided in the hydraulic excavator according to the first embodiment of the present invention (a display example of height data of the current terrain). 1 is a diagram showing an example of a guidance screen displayed on a monitor provided in the hydraulic excavator according to the first embodiment of the present invention (a display example of difference data in height between the designed topography and the current topography). 1 is a diagram showing an example of a guidance screen displayed on a monitor provided in the hydraulic excavator according to the first embodiment of the present invention (a display example of a cross section of the current topography). Explaining the principle behind the occurrence of unmeasurable areas 1 is a diagram showing an example of a guidance screen displayed on a monitor provided in the hydraulic excavator according to the first embodiment of the present invention (a display example of a field of view map). FIG. 10 is an explanatory diagram illustrating an example of a calculation algorithm for the amount of slope of the current terrain by a controller provided in the hydraulic excavator according to the first embodiment of the present invention. 1 is a diagram showing an example of a guidance screen displayed on a monitor provided in the hydraulic excavator according to the first embodiment of the present invention (a display example of a tilt amount diagram). 10 is a diagram showing an example of a guidance screen displayed on a monitor provided in the hydraulic excavator according to the first embodiment of the present invention (another example of displaying a tilt amount diagram). 1 is a flowchart showing the overall procedure for executing a measurement process of the current topography by a controller provided in a hydraulic excavator according to a first embodiment of the present invention. FIG. 10 is a diagram showing an example of an alarm displayed on a monitor provided in the hydraulic excavator according to the first embodiment of the present invention. FIG. 10 is a diagram showing another example of an alarm displayed on the monitor provided in the hydraulic excavator according to the first embodiment of the present invention; 1 is a flowchart showing details of an obstacle determination procedure performed by a controller provided in a hydraulic excavator according to a first embodiment of the present invention. 10 is a flowchart showing details of a data updating procedure performed by a controller provided in the hydraulic excavator according to the first embodiment of the present invention. 10 is a flowchart showing details of a procedure for displaying guidance by a controller provided in the hydraulic excavator according to the first embodiment of the present invention. 10 is a flowchart showing details of an obstacle determination procedure performed by a controller provided in a hydraulic excavator according to a second embodiment of the present invention. 10 is an example of a guidance screen displayed on a monitor provided in a hydraulic excavator according to a second embodiment of the present invention (a display example of a field of view map).

The following describes an embodiment of the present invention using the drawings.

First Embodiment
1. Hydraulic Excavator Fig. 1 is a side view showing the overall structure of a hydraulic excavator according to a first embodiment of the present invention. Hereinafter, the left side of Fig. 1 will be referred to as the front side of the hydraulic excavator (strictly speaking, the rotating body). The hydraulic excavator shown in the figure is configured to include a vehicle body 1 and a front work implement 2. The vehicle body 1 is configured to include a running body 3 and a rotating body 4.

1-1. Running Body The running body 3 is a foundation structure that enables the hydraulic excavator to travel under its own power. While a wheeled running body may be used, this embodiment illustrates a configuration in which a crawler-type running body is used. The running body 3 includes a track frame 5, idlers (driven wheels) 6, a running drive unit 7, sprockets (driving wheels) 8, and tracks (crawlers) 9. The track frame 5 is formed into an H-shape when viewed from above by a center frame 5a and a pair of parallel left and right side frames 5b connected to the center frame 5a. An idler 6 is rotatably supported at one end of each of the left and right side frames 5b, and a sprocket 8 is rotatably supported at the other end. The output shaft of the running drive unit 7 is connected to the rotation shaft of the sprocket 8. The running drive unit 7 is composed of a hydraulic motor for traveling and a reducer. A circular track 9 is looped between the idler 6 and the sprocket 8, and the running body 3 is self-propelled by driving the track 9 via the sprocket 8.

1-2. Swinging Unit The swinging unit 4 is rotatably mounted on the upper part of the running unit 3, and is composed of a swing frame 10, a cab 11, a counterweight 12, a machine room (engine room) 13, etc. The swing frame 10 is the base frame of the swinging unit 4, and is mounted on the upper part of the center frame 5a of the track frame 5 via a swing ring 14. A swing motor (not shown) is mounted on the swing frame 10 near the swing ring 14, and the output shaft of the swing motor meshes with a gear provided on the swing ring 14, causing the swinging unit 4 to swing relative to the running unit 3. Although an electric motor can be used as the swing motor, a hydraulic motor is used in this embodiment.

A cab 11 is installed at the front of the revolving frame 10, positioned to one side of the front work implement 2 in the left-right direction (the left side in this example). A machinery room 13 covered by a bonnet cover is installed behind the cab 11 on the revolving frame 10. A counterweight 12 is attached to the rear end of the revolving frame 10. The machinery room 13 houses a hydraulic system including a prime mover, a hydraulic pump driven by the prime mover, a control valve that controls pressurized oil from the hydraulic pump to hydraulic actuators (such as the boom cylinder 25), heat exchangers, tanks, various piping and wiring, etc. An electric motor may be used as the prime mover, but in this example, an internal combustion engine is used.

A monitor 15 (Figure 2) is also provided inside the cab 11. The monitor 15 functions as a guidance device that displays various data to assist the operator in their operations. In this embodiment, the monitor 15 is equipped with a terrain measurement button 42 (Figure 2) that commands measurement of the current terrain using a rangefinder S2 (described below). Operation of this terrain measurement button 42 triggers a measurement command signal, which the controller 30 uses to calculate the current terrain measurement data from the rangefinder S2 and display it on the monitor 15. The terrain measurement button 42 may be a button (icon) displayed on the screen of the monitor 15, as shown in Figure 4, or a mechanical switch such as a push button. If a mechanical switch is used, the terrain measurement button 42 does not need to be a component of the monitor 15, but may be attached to another structure (e.g., a console box or an operating lever for operating the front work implement 2) located within reach of the operator seated in the driver's seat.

1-3 Front Work Unit The front work unit 2 is attached to the rotating body 4 and is an articulated front work device including a work arm 21, a bucket (attachment) 24, a boom cylinder 25, an arm cylinder 26, and a bucket cylinder 27.

The working arm 21 is composed of a boom 22 and an arm 23. The boom 22 is rotatably connected to the front of the rotating unit 4 in the vertical direction, and the arm 23 is rotatably connected to the tip of the boom 22. The bucket 24 is rotatably attached to the tip of the arm 23. The boom cylinder 25 is connected at both ends to the rotating unit 4 and the boom 22. The arm cylinder 26 is connected at both ends to the boom 22 and the arm 23. The bucket cylinder 27 has its base connected to the arm 23 and its tip connected to the tip of the arm 23 and the bucket 24 via a link. The boom cylinder 25, arm cylinder 26, and bucket cylinder 27 are all hydraulic cylinders.

The front work implement 2 is also equipped with a reflector 28 that can be detected by a range finder S2 (described below). The reflector 28 is a reflective member for which the output of the range finder S2 (specifically, the intensity of the electrical signal obtained by photoelectrically converting the reflected laser light received by the range finder S2) is a known value. The reflector 28 is preferably provided in at least one location: the tip of the arm 23 of the front work implement 2, the base end of the bucket 24, and the longitudinal middle of the boom 22. In this embodiment, the reflector 28 is provided at the tip of the ventral side of the arm 23 of the front work implement 2 and the longitudinal middle of the left side of the boom 22.

1-4. Position Sensor The hydraulic excavator shown in FIG. 1 is equipped with a position sensor S1 (FIG. 2) as a position information acquisition device that acquires position data of the vehicle body 1 in real time. The position sensor S1 is a positioning device such as an RTK-GNSS (Real Time Kinematic - Global Navigation Satellite System). The position sensor S1 acquires position data in a global coordinate system of an antenna (not shown) installed on the vehicle body 1. By installing two antennas, the controller 30 (described below) can also calculate the direction data of the vehicle body 1 from the position data of the two antennas. The position of the vehicle body 1 acquired by the position sensor S1 is, strictly speaking, the position of the antenna installed on the vehicle body 1. However, this can be freely converted to a specific position of the vehicle body 1 (for example, the position of the rangefinder S2 or the center position of the vehicle body 1) using known dimensional data of the vehicle body 1. Although not specifically shown, a radio that receives correction data from a reference station GNSS (not shown) may also be installed on the hydraulic excavator. When this radio is used, the position data of the vehicle body 1 is corrected using the correction data received by the radio.

1-5. Rangefinder The hydraulic excavator shown in FIG. 1 is also equipped with a rangefinder S2 that measures distances to multiple ranging points on the current terrain around the vehicle body 1. In this embodiment, the rangefinder S2 uses LiDAR (Light Detection and Ranging). The rangefinder S2 emits multiple laser beams with optical axis angles shifted in the left-right direction (yaw direction) and the up-down direction (pitch direction), and measures the distance to each ranging point from the time it takes for the laser beam reflected from each ranging point to be received. From the output of the rangefinder S2, position data of each ranging point (point cloud) based on the position of the rangefinder S2 is obtained as measurement data. This rangefinder S2 obtains three-dimensional measurement data (point cloud data) of the terrain (shape of the earth's surface), and the rangefinder S2 functions as a terrain information acquisition device.

2. Controller Figure 2 is a functional block diagram of the controller provided in the hydraulic excavator shown in Figure 1. The controller 30 shown in the figure is an on-board computer that displays and outputs measurement data of the current topography based on the output of the range finder S2 on the monitor 15, and is configured to include an input unit 31, a memory 32, a processor 33, and an output unit 34.

2-1. Input Unit The input unit 31 is a signal input interface. In the example of Fig. 2, outputs from a position sensor S1, a distance meter S2, an MG system (machine guidance system) S3, a speedometer S4, and a key switch S5 are input to the controller 30 in real time via the input unit 31. If the input signals are analog signals, they are converted into digital signals by the input unit 31.

The MG system S3 is a type of computer, and in this embodiment, the MG system S3 is a computer separate from the controller 30, but the controller 30 may also have the functions of the MG system S3. The MG system S3 stores designed terrain data and map data for the construction site, and outputs map data and designed terrain data for the vicinity of the hydraulic excavator (host machine) and inputs them to the controller 30. The designed terrain data and map data are, for example, 3D polygon data. However, the map data does not need to be 3D data when it is displayed on the monitor 15 superimposed on the current terrain and unmeasurable areas, as described below. It may be 2D data, such as a planar map or mesh map containing only horizontal coordinate position data. Data input from the MG system S3 to the controller 30 can be configured to be executed in real time based on the output of the position sensor S1, for example, or can be executed in response to a request from the controller 30.

The speedometer S4 is a sensor that measures and outputs the vehicle speed (travel speed) of the hydraulic excavator, and may be mechanical, electrical, or electronic. The key switch S5 is a switch that turns the hydraulic excavator's power supply and prime mover on and off, and is located in the driver's cab 11.

2-2. Memory The memory 32 is a storage device and is appropriately configured with various storage media such as an HDD, RAM, ROM, and SSD. The memory 32 includes a main storage device 32a, which is a volatile memory, and an auxiliary storage device 32b, which is a non-volatile memory. The auxiliary storage device 32b of the memory 32 stores a display control program for the monitor 15 and various data required to execute the display control program. The various data stored in the auxiliary storage device 32b include measurement data of distance measurement points obtained by the rangefinder S2, and design topography data and map data of the construction site input from the MG system S3. The main storage device 32a temporarily stores various data input via the input unit 31, the display control program loaded from the auxiliary storage device 32b, measurement data of distance measurement points obtained by the rangefinder S2, design topography data and map data of the construction site, and the like. Various display processes are executed by the processor 33 in accordance with the display control program loaded into the main storage device 32a.

2-3. Processor The processor 33 is an arithmetic processing device such as a CPU, and generates and outputs display control signals to the monitor 15 in accordance with a program loaded from the auxiliary storage device 32b of the memory 32 to the main storage device 32a. Functions executed by the processor 33 include an obstacle determination function F1, a data update function F2, a difference calculation function F3, a field of view map creation function F4, and a tilt amount calculation function F5. Each of these functions is executed by the processor 33 in accordance with the display control program loaded into the main storage device 32a. The obstacle determination function F1, data update function F2, difference calculation function F3, field of view map creation function F4, and tilt amount calculation function F5 will be described later.

2, a display control signal is output from the controller 30 via the output unit 34, and the display control signal is input to the monitor 15. The monitor 15 displays messages such as alarms and graphics on the screen in response to the display control signal from the controller 30.

2-5. Obstacle Determination Function The obstacle determination function F1 is a function that determines whether an obstacle (in this example, the front work implement 2) is overlapping within the measurement range of the rangefinder S2 when the rangefinder S2 measures the current terrain in order to obtain measurement data of the current terrain (point cloud data of the ground surface). In other words, it is a function that determines whether the laser light emitted toward the current terrain is being blocked by the front work implement 2. For example, if the front work implement 2 is overlapping within the measurement range of the rangefinder S2 as shown in FIG. 1, some laser light, such as laser light L1 in the lower region within the measurement range, will reach the ground surface, while other laser light, such as laser light L2 in the upper region, will be blocked by the front work implement 2 and will not reach the ground surface. In this case, the distance measurement point P1 measured by the laser light L1 is data that truly represents the current terrain, but the distance measurement point P2 measured by the laser light L2 is distance information for the front work implement 2 and is not data that truly represents the current terrain. As described above, the front working implement 2 is equipped with the reflector 28, which has a known reflectivity for laser light, and the signal strength of the laser light reflected by the reflector 28 is known. Therefore, by having the controller 30 determine whether the output signal of the rangefinder S2 for each distance measurement point contains a signal of a set strength or greater, it is possible to determine whether the front working implement 2 overlaps within the measurement range of the rangefinder S2. The set strength set for the output signal is a value set based on the known signal strength of the laser light reflected by the reflector 28 (for example, a value set slightly lower than the known signal strength).

In this embodiment, when a signal is input from the terrain measurement button 42, the controller 30 calculates measurement data of the current terrain based on the output of the rangefinder S2 only if the vehicle speed V of the hydraulic excavator measured by the speedometer S4 is less than the set speed V1. The set speed V1 is a value set with the aim of ensuring a certain level of distance measurement accuracy by the rangefinder S2. In other words, when the vehicle speed V is equal to or greater than the set speed V1, it is presumed that a certain level of distance measurement accuracy cannot be expected and the state is unsuitable for obtaining measurement data of the current terrain. Therefore, the obstacle determination function F1 in this embodiment treats a case in which the vehicle speed V is equal to or greater than the set speed V1 as if an obstacle is present within the measurement range of the rangefinder S2, even if the obstacle is not present within the measurement range of the rangefinder S2. As will be described later using a flowchart, in this embodiment, even if the controller 30 is instructed to measure the terrain, if the rangefinder S2 determines that an obstacle is present, such as when it detects a reflector 28 between the current terrain and the rangefinder S2, the controller 30 stops measuring the current terrain. In other words, when the vehicle speed V is equal to or greater than the set speed V1, the controller 30 does not calculate the measurement data of the current terrain even if there are no obstacles within the measurement range of the rangefinder S2, and only when the vehicle speed V is less than the set speed V1 does the controller 30 calculate the measurement data of the current terrain, provided that there are no obstacles.

The data update function F2 is a function that determines whether or not the measurement data of the distance measurement points measured by the rangefinder S2, which is recorded in the auxiliary storage device 32b of the memory 32, needs to be updated based on the measurement date and time and the amount of change, and updates the measurement data as necessary.

In the data update function F2, the controller 30 compares the current measurement data of the current terrain measured by the rangefinder S2 and stored in the main memory device 32a when an operator inputs a terrain measurement command with the most recent measurement data. The most recent measurement data refers to the measurement data for the corresponding position (i.e., the corresponding horizontal coordinates (e.g., longitude and latitude)) stored in the auxiliary memory device 32b (or the most recent measurement data if multiple measurement data from different times are stored), and is read from the auxiliary memory device 32b. The controller 30 updates (records) the measurement data in the auxiliary memory device 32b in the memory 32 only for distance measurement points where the difference dH between the current measurement data and the most recent measurement data is equal to or greater than the set value dH1. The difference dH between the current measurement data and the most recent measurement data is the change in height of the distance measurement point (or mesh) corresponding to the horizontal coordinates (e.g., longitude and latitude). The set value dH1 is set with the aim of grasping the general progress of terrain development and prevents excessive updating of the measurement data in the auxiliary memory device 32b due to slight changes, such as those caused by measurement errors. The set value dH1 can be set to a fixed value, or it can be set as a percentage, such as 10% of the height data of the most recent measurement data. When setting the set value dH1 as a percentage, it can be selectively set between 5-30%, for example.

In the data update function F2, the controller 30 also compares the measurement dates and times of the current measurement data and the most recent measurement data, which correspond to each other's positions. The controller 30 updates the measurement data in the auxiliary storage device 32b (records the current measurement data) only for distance measurement points where the elapsed time T from the measurement date and time of the most recent measurement data to the measurement date and time of the current measurement data is equal to or greater than the set time T1. The set time T1 is a value that is set arbitrarily to prevent the measurement data of the current topography in the auxiliary storage device 32b from being updated more frequently than necessary, and can be set to, for example, about one hour.

Figure 3 is a schematic diagram illustrating an example of how the current terrain is measured using the range finder S2. In this figure, the current terrain CL is shown in a cross section cut by the operating plane of the front work implement 2 (a plane including the center lines of the arm cylinder 26 and bucket cylinder 27). In this figure, the ground surface of the current terrain CL is shown by a solid line, and the ground surface of the design terrain DL is shown by a dashed line. When the current terrain CL is measured using the range finder S2 in this figure, measurement data (point cloud of the current terrain CL) of each ranging point of the range finder S2 is obtained. In other words, because the angle of the optical axis of each laser beam (the line connecting each ranging point and the range finder S2) relative to the range finder S2 is known, by measuring the distance between the ranging point and the range finder S2, the position data of the ranging point on the optical axis of each laser beam can be uniquely determined as measurement data (point cloud). The controller 30 converts the point cloud data of the current terrain CL in the hydraulic excavator's local coordinate system thus acquired into data in the coordinate system of the map data (e.g., the global coordinate system) based on the current position of the vehicle body 1 acquired by the position sensor S1. As a result, the coordinate data of each distance measurement point measured by the rangefinder S2 is associated with the map data based on the position data of the vehicle body 1 acquired by the position sensor S1. The measurement data of the current terrain CL thus mapped on the map data is stored in the auxiliary storage device 32b of the memory 32 in accordance with the conditions described above, based on the elapsed time and amount of change since the most recent measurement data.

2-7. Difference Calculation Function The difference calculation function F3 is a function that calculates the difference H (FIG. 3) between the design terrain data and the measurement data of the current terrain CL, and displays it on the monitor 15. Based on the difference H calculated by the difference calculation function F3, the measurement data of the current current terrain CL, and the design terrain data, a graphic (FIG. 7) can be displayed on the monitor 15, in which the outline of the design terrain DL is superimposed on a vertical cross section of the current terrain CL. It is also possible to display a graphic (FIG. 6) on the monitor 15 that shows the remaining excavation volume (difference H) until the creation of the design terrain DL is completed, expressed as gradation or numerical values on the map data. The screen displayed by the difference calculation function F3 visually instructs the operator on the remaining excavation volume until the creation of the design terrain DL is completed.

2-7-1. Display example (designed terrain)
FIG. 4 shows an example of a guidance screen displayed on the monitor 15, illustrating an example of elevation data display for the designed terrain DL. The guidance screen in FIG. 4 displays icons such as a message field 41, a terrain measurement button 42, a designed terrain display button 43, a current terrain display button 44, a difference display button 45, a cross-section display button 46, a field of view map display button 47, an inclination display button 48, and a display window 49. The guidance screen in FIG. 4 is displayed on the monitor 15 by operating the designed terrain display button 43. The area displayed in the display window 49 is the area ahead of the hydraulic excavator, encompassing the measurement range of the rangefinder S2, and is divided into multiple meshes by boundary lines aligned in two horizontal directions. The elevation data for the designed terrain DL is displayed numerically for each mesh. The higher the elevation data value, the higher the point. In the example of FIG. 4, it can be seen that the designed terrain DL ahead of the hydraulic excavator is an uphill slope, as shown in FIG. 3. When multiple distance measurement points of the rangefinder S2 belong to one mesh, the controller 30 calculates the statistical value (average value, median value, etc.) of the heights of the multiple distance measurement points as height data for the mesh.

In addition, although not limited to this, in Figure 4 the mesh is color-coded according to the height value. In this specification, "color-coded" includes the use of shades of the same color. In the example in the figure, the higher the point, the darker the color, and if the terrain is uniformly sloping, the color change will also be uniform.

2-7-2. Display example (current topography)
Figure 5 is a diagram showing an example of a guidance screen displayed on the monitor 15, and is an example of a display of height data for the current terrain CL. The guidance screen in Figure 5 is a screen displayed on the monitor 15 by operating the current terrain display button 44. The area displayed in the display window 49 is the same as that in Figure 4, and height data for the current terrain CL is displayed as a numerical value for each mesh. The height data numerical values and mesh color coding shown in Figure 5 correspond to the example in Figure 4.

2-7-3. Display example (difference between design topography and current topography)
FIG. 6 is a diagram showing an example of a guidance screen displayed on the monitor 15, and is an example of a display of height difference data between the design terrain DL and the current terrain CL. The guidance screen in FIG. 6 is a screen displayed on the monitor 15 by operating the difference display button 45. The area displayed in the display window 49 is the same area as in FIGS. 4 and 5, and height difference data between the design terrain DL and the current terrain CL (in this example, the difference between the data in FIGS. 4 and 5) is displayed numerically for each mesh. The larger the numerical value in FIG. 6, the greater the difference in height between the design terrain DL and the current terrain CL. In the examples of FIGS. 4 to 6, it can be seen that the difference between the design terrain DL and the current terrain CL is relatively large in areas farther forward from the hydraulic excavator.

In addition, although not limited to this, in Figure 6, meshes are color-coded (including shades of the same color) according to the difference in altitude between the design terrain DL and the current terrain CL. In the example of Figure 6, meshes with a greater difference in altitude between the design terrain DL and the current terrain CL are colored darker, and the operator is visually informed by the darker color of the areas that need to be cut to bring the current terrain CL closer to the design terrain DL.

2-7-4. Display example (cross section of current topography)
FIG. 7 is a diagram showing an example of a guidance screen displayed on the monitor 15, showing one example of a cross section of the current terrain CL. The guidance screen of FIG. 7 is a screen displayed on the monitor 15 by operating the cross section display button 46. The terrain cross section displayed in the display window 49 represents a vertical cross section cut by the operating plane of the front work implement 2, as in the schematic diagram of FIG. 3. In this figure, in addition to the ground surface of the current terrain CL (solid line), the ground surface of the design terrain DL (dashed line) is also shown, and the difference between the current terrain CL and the design terrain DL is simulated. The cross section of the current terrain CL can be displayed by calculating the intersection line between the ground surface of the current terrain CL calculated from measurement data and the operating plane of the front work implement 2. Similarly, the cross section of the design terrain DL can be displayed by calculating the intersection line between the ground surface of the design terrain DL calculated from design terrain data and the operating plane of the front work implement 2. In Figure 7, a scale I for grasping the height of the terrain as data is displayed superimposed on the undulating portions of the current terrain CL and the design terrain DL. The height of the scale I corresponds to the numerical value used to evaluate the height of the terrain in Figures 4 and 5. The color coding of the height on the scale I also corresponds to the color coding of the meshes in Figures 4 and 5.

2-8. Sight Map Creation Function The sight map creation function F4 is a function that creates a sight map (Figure 9) based on the output of the rangefinder S2 and displays it on the monitor 15. The sight map is the measurement range of the rangefinder S2. The sight map displays the area where the terrain is currently being measured by the rangefinder S2. This sight map also displays areas within the measurement range of the rangefinder S2 where the terrain is not currently being measured (areas where the height cannot be measured, hereinafter referred to as "unmeasurable areas").

An example of the calculation of a field of view map by the controller 30 will now be described. The controller 30 first calculates the horizontal coordinates (e.g., longitude and latitude) of the measurement data for each ranging point based on the current position data of the vehicle body 1 acquired by the position sensor S1, the map data read from the auxiliary storage device 32b of the memory 32, and the output of the rangefinder S2. This procedure can be shared with the process of mapping the current terrain data onto the map data using the data update function F2. Specifically, based on the position data of the vehicle body 1 acquired by the position sensor S1, the coordinate data of each ranging point measured by the rangefinder S2 is associated with the map data.

Next, the controller 30 calculates the horizontal distance W between adjacent ranging points for each of the ranging points of the rangefinder S2. The distance W calculated here is the horizontal distance (i.e., in a planar view) between two ranging points where two adjacent laser beams are reflected, either vertically or horizontally, and can be calculated from the horizontal coordinates of the two ranging points. The controller 30 compares each of the horizontal distances between adjacent ranging points thus calculated with a set distance W1. The set distance W1 is an arbitrarily set value, but as an example, the length of one side or diagonal of one mesh shown in Figure 4 can be used.

The controller 30 then records the height data calculated based on the output of the rangefinder S2 for distance measurement points whose spacing W between adjacent distance measurement points is equal to or less than the set spacing W1 in memory 32 as measurement data for the current terrain CL and displays it on the monitor 15. At this time, the controller 30 can also display map data on the monitor 15 and overlay the measurement data for the current terrain CL on the map data. Areas where height data is displayed are presumed to be areas where the current terrain CL was truly measured. The controller 30 also records in memory 32 and displays on the monitor 15 a message indicating that an area whose spacing W between adjacent distance measurement points is greater than the set spacing W1 is an unmeasurable area where height measurement is not possible. At this time, the controller 30 can also display map data on the monitor 15 and overlay the unmeasurable area on the map data.

2-8-1. Unmeasurable Areas Figure 8 is an explanatory diagram of the principle behind the occurrence of unmeasurable areas. First, the angle between adjacent laser optical axes on the top, bottom, or left, right, of the rangefinder S2 and the size of the mesh shown in Figure 4 and other figures are set under the assumption that, if the shape of the terrain being measured is monotonous, the horizontal distance between adjacent ranging points will be shorter than the actual distance corresponding to the length of one side of the mesh. As shown in Figure 8, for example, if adjacent laser beams L3 and L4 are irradiated from the rangefinder S2 to ranging points P3 and P4 on a monotonous uphill slope of the current terrain CL, the spacing W between ranging points P3 and P4 will be shorter than the distance corresponding to one side of the mesh. In this case, no unmeasured areas (mesh) will occur between adjacent ranging points P3 and P4.

However, if there is a depression Z in the measurement range as shown in Figure 8, the horizontal distance S between measurement points P5 and P6 measured by adjacent laser beams L5 and L6 will increase. In this case, if the spacing W between adjacent measurement points P5 and P6 is longer than the distance equivalent to one side of the mesh, an area (mesh) where measurement is not possible may occur between measurement points P5 and P6. Since the position of each measurement point on the map data can be determined, meshes with no measurement points can be identified on the map as unmeasurable areas.

2-8-2. Display example (field of view map)
Figure 9 is a diagram showing an example of a guidance screen displayed on the monitor 15, and is an example of a display of a field of view map. The guidance screen in Figure 9 is a screen displayed on the monitor 15 by operating the field of view map display button 47. The area displayed in the display window 49 is the same area as in Figures 4 to 6, and as in Figure 5, the elevation data of each point on the current topography CL is displayed numerically and color-coded for each mesh.

In addition, in Figure 9, the measurement range currently being measured by the rangefinder S2 is represented by indicator lines B1 and B2. The current measurement points are concentrated in the area between indicator lines B1 and B2, and the meshes between indicator lines B1 and B2 where height data is displayed represent the points where the height is currently being measured. Meshes that are within the measurement range between indicator lines B1 and B2 but are not measured, such as depression Z shown in Figure 8, are displayed as unmeasurable area A. Figure 9 shows an example in which the meshes representing unmeasurable area A are displayed in white and the height values are not displayed.

2-9. Slope Calculation Function The slope calculation function F5 is a function that calculates and displays the slope of each measurement point on the current terrain CL based on the measurement data of each measurement point on the current terrain CL. The slope is, for example, the angle of the ground surface with respect to the horizontal plane; the smaller the slope of the ground surface, the closer to horizontal it is, and the larger the slope, the closer to vertical it is. As will be described later, the controller 30 calculates the slope of each measurement point on the current terrain CL based on the height data of each measurement point (mesh in this example), and displays a slope map (Figures 11 and 12) on the monitor 15, overlaid on the map data.

2-9-1. Slope Amount Calculation Algorithm Figure 10 is an explanatory diagram of an example of an algorithm for calculating the slope amount of the current terrain by the controller 30. This figure shows nine meshes, M11-M13, M21-M23, and M31-M33, arranged in three rows and three columns, extracted from the measurement data of the current terrain CL measured by the rangefinder S2. The heights of meshes M11-M13, M21-M23, and M31-M33 are H11-H13, H21-H23, and H31-H33, respectively, with the horizontal spacing between the meshes being Dx and the vertical spacing being Dy. The slope amount IA of the area represented by these nine meshes can be calculated using the least squares method as follows:

IA=√(Sx ² +Sy ² )...(Formula 1)
Sx=(H11+H21+H31-(H13+H23+H33))/6Dx
Sy=(H11+H12+H13-(H31+H32+H33))/6Dy

For example, the controller 30 can calculate the amount of tilt for each mesh by shifting the nine meshes for which the amount of tilt is to be calculated by one mesh at a time and calculating the value of IA using the above equation 1.

2-9-2. Display example (inclination amount diagram-1)
FIG. 11 is a diagram showing an example of a guidance screen displayed on the monitor 15, and is an example of a slope map. The guidance screen in FIG. 11 is a screen displayed on the monitor 15 by operating the slope display button 48. The area displayed in the display window 49 is the same as that shown in FIGS. 4-6 and 9, and the slope is displayed in different colors for each mesh. In the example shown in FIG. 11, meshes with smaller slopes are displayed in lighter colors, while meshes with larger slopes are displayed in darker colors. For example, areas with gentle slopes that are nearly horizontal are displayed in lighter colors overall, while areas with large undulations are displayed in darker colors overall. Therefore, whether the ground surface is nearly horizontal or steeply inclined, areas with minimal surface irregularities will have less color change on the slope map display. Also, unlike the altitude display shown in FIG. 5, in the slope map shown in FIG. 11, areas with gentle slopes even at high elevations are displayed in lighter colors, and conversely, areas with steep slopes even at low elevations are displayed in darker colors.

Note that if an unmeasurable area A exists, it is not possible to simply calculate the amount of tilt IA using the above formula 1 in that area. For this reason, in the example of Figure 11, the amount of tilt is not displayed for the unmeasurable area A, and it is displayed in white, just like in Figure 9.

2-9-3. Display example (inclination amount diagram-2)
Figure 12 is a diagram showing an example of a guidance screen displayed on the monitor 15, and is another example of the display of a slope map. The second example of the slope map shown in Figure 12 is also displayed on the monitor 15 by operating the slope display button 48, for example. The example of Figure 12 differs from the example of Figure 11 in that the elevation data (Figure 5) of the current terrain CL is displayed in the mesh area of the display window 49, and the slope map TD corresponding to the measurement range of the rangefinder S2 is displayed superimposed on the mesh area.

In this embodiment, the tilt amount diagram TD corresponding to the current measurement range of the rangefinder S2 can be displayed in mesh units as shown in Figure 11, but Figure 12 shows an example of a high-resolution display in units of distance measurement points. The tilt amount calculation algorithm can calculate the value of IA by applying the height data of nine distance measurement points measured using nine laser beams arranged in three rows and three columns adjacent vertically and horizontally to the above formula 1. Note that the value of Dx used in the above formula 1 can be, for example, a statistical value (e.g., average value) of the left-right spacing of the nine distance measurement points. Similarly, the value of Dy can be, for example, a statistical value (e.g., average value) of the front-to-back spacing of the nine distance measurement points.

Figure 12 also illustrates a case where there is an unmeasurable area A within the current measurement range. Unmeasurable area A does not display any slope information and is displayed in white. Furthermore, the display area of the slope map TD (i.e., the current measurement range) may be displayed in a simpler manner, as shown by the indicator lines B1 and B2 in Figure 9.

3. Actions - Guidance -
Figure 13 is a flowchart showing the overall procedure for executing processing for measuring the current topography by the controller 30. The flowchart shown in Figure 13 is started by being triggered, for example, by the power-on of the hydraulic excavator (power being supplied to the controller 30) based on a signal from the key switch S5 (Figure 2). The controller 30 constantly executes the flow shown in the figure while the power of the hydraulic excavator is on.

Step S10
13 starts, the controller 30 first determines whether the power to the hydraulic excavator remains on based on a signal from the key switch S5 (step S10). If the key switch S5 is turned off, the controller 30 executes a termination process and ends the flow of FIG.

Step S20
If the key switch S5 is on, the controller 30 determines whether the operator has issued an instruction to measure the current topography CL (step S20). If the operator has not operated the topography measurement button 42 and a signal instructing measurement of the current topography CL has not been input from the monitor 15, the controller 30 returns the procedure from step S20 to step S10.

Step S30
When the operator operates the terrain measurement button 42 and a signal instructing measurement of the current terrain CL is input from the monitor 15, the controller 30 temporarily stores the latest output values of each sensor, which are input in real time, in the main storage device 32a of the memory 32 (step S30). The sensor outputs temporarily stored here are, for example, the outputs of the position sensor S1, the distance meter S2, the MG system S3, and the speedometer S4.

Step S40
After temporarily storing the necessary sensor outputs in response to instructions from the operator, the controller 30 determines whether an obstacle (front working implement 2) is present within the measurement range of the range finder S2 based on the output of the range finder S2 (step S40). The procedure in step S40 corresponds to the obstacle determination function F1 described above. The procedure in step S40 will be described in detail later (FIG. 16).

Step S50
If it is determined that an obstacle is overlapping within the measurement range of the range finder S2, the controller 30 outputs a signal to the monitor 15, causes the monitor 15 to display an alarm, and returns the procedure to step S10 (step S50).

Figure 14 shows an example of an alarm display. As will be described later, if the front working implement 2 overlaps the measurement range of the distance meter S2, it is determined in step S40 that an "obstacle is present." The display example in Figure 14 is an example in which an alarm message is displayed to notify the operator that the front working implement 2 is obstructing the measurement of the current terrain CL. The message "Raise the front" is also displayed in message field 41, urging the operator to move the front working implement 2 out of the measurement range of the distance meter S2.

Figure 15 shows another example of an alarm display. In this embodiment, if the hydraulic excavator is moving at a certain speed or above, it is treated in step S40 as if there is an obstacle, and a determination is made that "obstacle present." The display example in Figure 15 shows an example in which, in such a situation, an alarm message saying "Please stop" is output in message field 41, urging the operator to stop the vehicle body 1.

The examples in Figures 14 and 15 show an example of outputting an alarm message, but the controller 30 may input a command signal to a speaker or the like provided on the monitor 15 or installed separately, so that an alarm sound is output along with the alarm message.

Step S60
If it is determined that no obstacles are overlapping within the measurement range of the range finder S2, the controller 30 measures the current terrain CL (actual measurement) and temporarily stores the current output values of the various sensors, which are input in real time, in the main memory device 32a (step S60). During this measurement procedure, the controller 30 temporarily stores the measurement data of each distance measurement point on the current terrain CL, along with the measurement date and time data, in the main memory device 32a. In this embodiment, during the measurement of the current terrain CL in step S60, the controller 30 applies an interlock to disable operation of the hydraulic excavator. At this time, for example, as shown in FIG. 5, a message informing the operator of the current situation, such as "Machine operation is not permitted during terrain measurement," is displayed in the message field 41 of the guidance screen on the monitor 15.

Step S70
After measuring the current topography CL, the controller 30 updates the measurement data of the current topography CL stored in the auxiliary storage device 32b of the memory 32 (step S70). This step S70 corresponds to the data update function F2 described above. The details of the step S70 will be described later (FIG. 17).

Step S80
After updating the measurement data database, the controller 30 displays various information about the current measurement range of the rangefinder S2 on the monitor 15 in the format selected by the operator, and returns to step S10 (step S80). In step S80, the difference calculation function F3, field of view map creation function F4, slope calculation function F5, etc. are executed as appropriate, depending on the operator's selection. The details of step S80 will be described later (FIG. 18).

As described above, in this embodiment, the controller 30 does not display the current terrain CL in real time, but rather uses a measurement instruction input by the operator when he operates the terrain measurement button 42 as a trigger to calculate measurement data for the current terrain CL and display it on the monitor 15.

- Obstacle detection -
FIG. 16 is a flowchart showing the details of the procedure for obstacle determination (step S40) of FIG. 13 by the controller 30.

Step S41
When the procedure of step S40 starts, the controller 30 determines whether or not a reflector 28 is detected between the current terrain CL and the rangefinder S2 based on the output of the rangefinder S2 read in step S30 (step S41). As described above, whether or not the reflector 28 is detected can be determined by comparing the signal strength of each laser beam reflected at each distance measurement point and detected by the rangefinder S2 with a set strength and determining whether or not a signal strength equal to or greater than the set strength is detected. If the output of the rangefinder S2 includes a signal equal to or greater than the set strength, the controller 30 determines that the front working implement 2 is within the measurement range of the rangefinder S2, ends the flow of FIG. 16 (advances to step S50 of FIG. 13), and issues an alarm (e.g., FIG. 14).

Step S42
If the output of the rangefinder S2 does not include a signal of equal to or greater than the set intensity, the controller 30 determines whether the vehicle speed V is less than the set speed V1 based on the output of the vehicle speedometer S4 read in step S30 (step S42). If the vehicle speed V is equal to or greater than the set speed V1, the controller 30 ends the flow of Fig. 16 (advancees to step S50 of Fig. 13) and outputs an alarm (see, for example, Fig. 15). In this embodiment, even if the front working implement 2 does not overlap within the measurement range of the rangefinder S2, if the vehicle speed V is equal to or greater than the set speed V1 and the situation is not suitable for measuring the current topography CL, the situation is treated as if there is an obstacle within the measurement range of the rangefinder S2 and an alarm is output.

If the output of the rangefinder S2 does not include a signal of a set intensity or greater, and the vehicle speed V is less than the set speed V1, it is assumed that there are no obstacles and that the conditions are suitable for measuring the current terrain CL. In this case, the controller 30 ends the flow in Figure 16 (advances to step S60 in Figure 13) and measures the current terrain CL.

-Data update-
FIG. 17 is a flowchart showing the details of the procedure for updating data (step S70) of FIG. 13 by the controller 30.

Step S71
When the procedure of step S70 is started, the controller 30 converts the current measurement data of the current topography CL temporarily stored in step S60 into data in the coordinate system of the construction site (for example, the global coordinate system) based on the position data of the hydraulic excavator at the same time (step S71). In this embodiment, the construction site is divided into a large number of meshes (FIG. 4) in the coordinate system of the construction site (for example, the global coordinate system), and the measurement data by the rangefinder S2 is converted into height data for the meshes. When multiple measurement points belong to the same mesh, statistical values (average value or median value) can be calculated as height data for the mesh.

Step S72
After converting the current measurement data into the on-site coordinate system, the controller 30 determines, based on the coordinate data of the measurement data, whether some or all of the meshes of the current measurement data have been measured in the past (step S72). If no mesh measurement data is stored in the auxiliary storage device 32b and all meshes of the current measurement data have not been measured, the controller 30 proceeds to the data update procedure in step S77. Conversely, if measurement data for at least one mesh is stored in the auxiliary storage device 32b, the controller 30 proceeds to the procedure in step S73.

Step S73
If at least a portion of the measurement range of the current measurement data overlaps with an area that has already been measured, the controller 30 reads the measurement date and time of the most recent measurement data whose position corresponds to the current measurement data from the auxiliary memory device 32b and temporarily stores it in the main memory device 32a (step S73).

Step S74
Next, the controller 30 calculates the elapsed time T by taking the difference between the measurement dates and times of the current measurement data and the most recent measurement data, which correspond to each other, and determines whether the elapsed time T is less than the set time T1 read from the auxiliary storage device 32b (step S74). If the elapsed time T is equal to or greater than the set time T1, the controller 30 proceeds to the data update procedure in step S77. If the elapsed time T is less than the set time T1, the controller 30 proceeds to the procedure in step S75.

Step S75
If the elapsed time T is less than the set time T1, the controller 30 calculates the height data difference dH between the current measurement data and the most recent measurement data that correspond to each other in position (step S75).

Step S76
Next, the controller 30 determines whether the difference dH calculated in step S75 is less than the set value dH1 read from the auxiliary storage device 32b (step S76). If the difference dH is equal to or greater than the set value dH1, the controller 30 proceeds to the data update procedure in step S77. If the difference dH is less than the set value dH1, the controller 30 ends the flow of FIG. 17 without updating the measurement data in the auxiliary storage device 32b and proceeds to step S80 (FIG. 13).

Step S77
If the determinations in steps S72, S74, and S76 are not satisfied, the controller 30 links the current measurement data (height data for each mesh and each ranging point) obtained in the current measurement with the measurement date and time and records them in the auxiliary storage device 32b of the memory 32 (step S77). That is, if all meshes included in the measurement data obtained in the current measurement have not yet been measured, if a set time T1 or more has elapsed since the previous measurement, or if the difference dH from the previous measurement data is a set value dH1 or more, the measurement data in the auxiliary storage device 32b is updated. After updating the measurement data in the auxiliary storage device 32b in this way, the controller 30 ends the flow of FIG. 17 and proceeds to step S80 (FIG. 13).

Note that the measurement data for the unmeasurable area A' (Figure 11, etc.) is distinguished from the measurement data for the current topography CL and is not reflected in the measurement data for the current topography CL in the auxiliary storage device 32b.

- Display processing -
Figure 18 is a flowchart showing the details of the procedure for displaying the guidance shown in Figure 13 by the controller 30 (step S80). When the procedure in step S80 starts, the controller 30 determines the display mode selected by the operator on the guidance screen of the monitor 15 (steps S81-S86). Specifically, based on a signal from the monitor 15, the controller 30 determines which of the design terrain display button 43, current terrain display button 44, difference display button 45, cross section display button 46, field of view map display button 47, and slope display button 48 has been selected. The controller 30 then displays data corresponding to the operation on the monitor 15 in a display mode corresponding to the operation (steps S81a-S86a).

Specifically, if the Design Terrain Display button 43 is operated, the controller 30 outputs a display control signal to the monitor 15 to display the design terrain DL data (e.g., Figure 4) (steps S81 and S81a). If the Current Terrain Display button 44 is operated, the controller 30 outputs a display control signal to the monitor 15 to display the measurement data of the current terrain CL (e.g., Figure 5) (steps S82 and S82a). If the Difference Display button 45 is operated, the controller 30 outputs a display control signal to the monitor 15 to display the data of the difference dH between the design terrain DL and the current terrain CL (e.g., Figure 6) (steps S83 and S83a). If the Cross-Section Display button 46 is operated, the controller 30 outputs a display control signal to the monitor 15 to display a cross-section of the design terrain DL and the current terrain CL (e.g., Figure 7) (steps S84 and S84a). If the field of view map display button 47 is operated, the controller 30 outputs a display control signal to the monitor 15 to display a field of view map (e.g., Figure 9) (steps S85, S85a). If the tilt display button 48 is operated, the controller 30 outputs a display control signal to the monitor 15 to display a tilt amount map (e.g., Figure 11 or Figure 12) (steps S86, S86a).

After executing any of steps S81a-86a, the controller 30 determines whether the operator has performed an operation to end the measurement (step S87), and if not, returns to step S81. The operation to end the measurement can be determined, for example, by identifying the operation of the end button FB (Figure 4) displayed on the guidance screen of the monitor 15 based on a signal from the monitor 15. If the operator has performed an operation to end the measurement, the controller 30 ends the flow in Figure 18 and returns to step S10 (Figure 13).

-effect-
(1) According to this embodiment, as described above, if an unmeasurable area A whose height cannot be measured exists within the measurement range based on the output of the rangefinder S2, the unmeasurable area A is displayed on the monitor 15. As described above, according to this embodiment, the operator can clearly confirm not only the area currently being measured by the rangefinder S2 but also areas that have not yet been measured through the guidance display on the monitor 15, and can grasp the areas that truly represent the current topography CL.

Also, there is a type of guidance that generally displays the position of the bucket tip together with the design terrain on a monitor in real time. However, in order to obtain basic information for calculating the position of the bucket tip, such guidance display requires an inclination sensor (e.g., an IMU) that detects the inclination angle of the vehicle body and multiple angle sensors that detect the angles of the boom, arm, and bucket. In contrast, the present embodiment does not require an inclination sensor or angle sensor to display the guidance screen, which has the advantage of reducing the number of parts and manufacturing costs of the hydraulic excavator.
(2) Furthermore, by displaying the unmeasurable area A on the monitor 15 in a state where it is superimposed on the map data, the position of the unmeasurable area A on the map can be accurately notified to the operator.
However, as long as the above-mentioned essential effect (1) is obtained, the function of displaying the unmeasurable area A superimposed on the map data is not essential. For example, when displaying the unmeasurable area A in the local coordinate system, the position sensor S1 and the map data are not necessarily required.

(3) The difference dH between the design terrain DL and the current terrain CL (measured terrain) is displayed on the monitor 15, allowing the operator to confirm the amount of excavation required to create the design terrain DL and easily grasp the progress of the creation work. By displaying the difference dH in a mesh display (plan view) as shown in Figure 6, the distribution of the difference dH can be presented to the operator in an easy-to-understand manner. Furthermore, by displaying the difference dH in a cross section as shown in Figure 7, the current terrain CL relative to the design terrain DL can be visually presented to the operator.

(4) By installing a reflector 28 on the front working implement 2, it is possible to determine whether the front working implement 2 is within the measurement range of the rangefinder S2. If the front working implement 2 is within the measurement range of the rangefinder S2, an alarm can be displayed and output on the monitor 15 to indicate that the front working implement 2 is interfering with the measurement of the current terrain CL. This makes it possible to prompt the operator to move the front working implement 2 out of the measurement range of the rangefinder S2 when measuring the current terrain CL. By moving the front working implement 2 out of the measurement range of the rangefinder S2 in this way, it is possible to avoid the front working implement 2 interfering with the measurement of the current terrain CL. By avoiding the distance measurement of the front working implement 2 and truly measuring the current terrain CL, the operator can make an appropriate judgment on the success of the terrain creation.

(5) Because the reflector 28 is provided at the tip of the arm 23 of the front work implement 2 and at the longitudinal middle of the boom 22, when the front work implement 2 overlaps within the measurement range of the rangefinder S2, the front work implement 2 can be detected rationally by the rangefinder S2. This rationally eliminates the impact on terrain measurement caused by the front work implement 2 interfering with the measurement range of the rangefinder S2.

(6) If the current terrain CL is displayed on the monitor 15 in real time based on measurement data input from the rangefinder S2 as needed, and the front working implement 2 moves around within the measurement range of the rangefinder S2, the measurement data of the front working implement 2 may be reflected in the display, making the current terrain CL unclear. Furthermore, when operating the front working implement 2 while looking at the display, the front working implement 2 usually overlaps the measurement range of the rangefinder S2, so in order to check the current terrain CL, the front working implement 2 must be moved away from the area to be checked and the display must be checked again. Furthermore, displaying the current terrain CL in real time places a load on the controller 30.

In contrast, in this embodiment, rather than displaying the current terrain CL in real time, the current terrain CL is measured and displayed on the monitor 15 in response to a measurement command input by operating the terrain measurement button 42. In other words, the operator can measure and check the current terrain CL at any time. Therefore, for example, if the operator wants to check the current terrain CL during construction work, he or she can stop construction, move the front work implement 2 out of the measurement range of the rangefinder S2, and then manually issue a measurement command. This procedure allows the current terrain CL to be checked timely and accurately. Even if the operator forgets to move the front work implement 2 out of the measurement range of the rangefinder S2 during terrain measurement, as described above, the front work implement 2 is notified that it is within the measurement range of the rangefinder S2, thereby rationally preventing the front work implement 2 from affecting the measurement data of the current terrain CL. Furthermore, compared to displaying the current terrain CL in real time, displaying the current terrain CL at the operator's desired time reduces the load on the controller 30.

In addition, compared to displaying the positional relationship between the bucket and the design terrain in real time, for example, the screen in Figure 7 shows a simple guidance screen that statically displays the relationship between the current terrain CL and the design terrain DL. By displaying a simple, static guidance screen that avoids displaying more information than necessary, the operator can be informed of the progress of the work in an easy-to-understand manner.

However, as long as the essential effect (1) above is achieved, the measurement range and unmeasurable area A may be displayed in real time.

(7) Furthermore, in this embodiment, measurement data for the current terrain CL is calculated only when the vehicle speed V is less than the set speed V1, and the current terrain CL is not measured when the vehicle speed V is equal to or greater than the set speed V1. While the reliability of the measurement data from the rangefinder S2 can decrease when traveling at a high speed or higher, the reliability of the measurement data for the current terrain CL can be ensured by measuring the current terrain CL only when the vehicle speed V is less than the set speed V1.

However, as long as the essential effect (1) described above is achieved, calculation of the measurement data for the current terrain CL may be performed regardless of the vehicle speed V.

(8) Furthermore, when the current terrain CL is newly measured, the data in memory 32 (auxiliary storage device 32b) is updated only for distance measurement points where the difference dH from the most recent measurement data is equal to or greater than the set value dH1. Compared to replacing unchanged measurement data with existing data, updating only measurement data that has changed to a certain extent from existing data (including measurement data from the first measurement) reduces the load on the controller 30 associated with data communication and storage for data updates.

However, as long as the essential effect (1) described above is achieved, the measurement data for the current topography CL may be updated regardless of the difference dH.

(9) Because the operator can visually check the current topography CL from the driver's cab 11, it is expected that the current topography CL will be checked using measurement data at key points during the construction work. Therefore, there is not necessarily a strong need to update measurement data excessively for areas where measurements have been taken only recently.

In this embodiment, when the current topography CL is newly measured, the data in memory 32 (auxiliary storage device 32b) is updated only for distance measurement points where the elapsed time T from the measurement date and time of the most recent measurement data is equal to or greater than the set time T1. By avoiding excessive data updates in this way, the load on the controller 30 associated with data communication and storage for data update processing can be reduced.

However, even if the above-mentioned measurements were taken recently, if data needs to be updated for an area where a certain level of change in development progress is observed, the measurement data may be updated regardless of the time elapsed since the last measurement.

(10) In this embodiment, the amount of slope of the current terrain CL can be superimposed on the map data and displayed on the monitor 15, as shown in Figures 11 and 12. In this case, it is not only useful for determining the quality of the current terrain CL, but also provides data such as the amount of slope of the ground on which the hydraulic excavator will be touching down, and can also inform the operator of the gradient of the area to which the vehicle body 1 will be moving.

However, as long as the essential effect (1) above is achieved, the function to display the gradient map is not essential.

(11) As explained using Figure 18, in response to the operator's display switching operation, the measurement data for the current topography CL can be presented in various forms, such as a mapping display of the difference dH (Figure 6), a cross-sectional display (Figure 7), a field of view map (Figure 9), and a slope map (Figures 11 and 12). This allows the operator to flexibly grasp the current state of the construction work by checking the current topography CL in one or more desired forms.

Second Embodiment
In the first embodiment, an example was described in which, if the front working implement 2 overlaps within the measurement range of the rangefinder S2, an alarm is output without measuring the current terrain CL, and the operator is prompted to move the front working implement 2 out of the measurement range. In contrast, in the second embodiment, measurement of the current terrain CL can be performed even if the front working implement 2 overlaps within the measurement range of the rangefinder S2, and an area in which the current terrain CL cannot be measured by the front working implement 2 is displayed on the field of view map as an unmeasurable area A.

Figure 19 is a flowchart showing details of the obstacle determination procedure (step S40) of Figure 13 performed by the controller 30 in the second embodiment. As shown in Figure 19, in this embodiment, the reflector detection procedure (step S41) in the first embodiment is omitted, and when a command to measure the current terrain CL is issued, it is simply determined whether the vehicle speed V is less than the set speed V1 (step S42). If the vehicle speed V is equal to or greater than the set speed V1, the controller 30 ends the flow of Figure 19 (advances to step S50 of Figure 13) and outputs an alarm (e.g., Figure 15). Conversely, if the vehicle speed V is less than the set speed V1, the controller 30 ends the flow of Figure 16 (advances to step S60 of Figure 13) and measures the current terrain CL.

Figure 20 is an example of a guidance screen (field of view map) displayed on the monitor 15 in the second embodiment. The guidance screen in Figure 20 is a screen displayed on the monitor 15 by operating the field of view map display button 47, and is a diagram equivalent to the field of view map of the first embodiment shown in Figure 9. In Figure 20, it is assumed that the front working implement 2 overlaps the measurement range of the rangefinder S2, and in addition to the unmeasurable area A due to the terrain caused by the depression Z (Figure 8), an unmeasurable area A' due to the front working implement 2 is displayed within the current measurement range of the rangefinder S2 represented by the indication lines B1 and B2.

As in the first embodiment, the unmeasurable area A' caused by the front work implement 2 can be identified by detecting the reflector 28 and estimating the position of the front work implement 2 within the measurement range of the rangefinder S2. Furthermore, the front work implement 2 is discontinuous (floating) or overhanging relative to the ground surface when viewed from the rangefinder S2. Taking this into consideration, for example, by comparing two vertically adjacent measurement points using two laser beams, if measurement point P8 using the upper laser beam is closer to the vehicle body 1 than measurement point P7 using the lower laser beam, it can be estimated that measurement point P8 is an obstacle such as the front work implement 2. When the front work implement 2 is identified based on the relative positions of the measurement points in this way, the reflector 28 can be omitted. By applying the algorithm described above, the front work implement 2 can be identified by the controller 30, and the unmeasurable area A' can be reflected in the field of view map.

Note that, like the measurement data for the unmeasurable area A, the measurement data for the unmeasurable area A' is distinguished from the measurement data for the current topography CL, and is not reflected in the measurement data for the current topography CL in the auxiliary storage device 32b in step S77 (Figure 17).

Apart from the above, the rest of the configuration and processing by the controller 30 of this embodiment are the same as those of the first embodiment.

This embodiment also achieves the same effects as the first embodiment. Furthermore, in this embodiment, the current terrain CL can be measured even if the front work implement 2 overlaps the measurement range of the rangefinder S2. As a result, for example, if the front work implement 2 is clearly outside the area where the terrain needs to be measured as viewed from the driver's cab 11, the operator can confirm the desired information without having to move the front work implement 2 out of the measurement range of the rangefinder S2 each time.

<Modification>
In the above embodiment, the rangefinder S2 has been described as an example of a type that transmits and receives multiple laser beams to obtain point cloud data of the current topography CL, but it may also be a type that obtains point cloud data by scanning the current topography CL with laser beams. Also, while the rangefinder S2 has been described as an example of a type that uses LiDAR, a stereo camera, millimeter-wave radar, laser radar, an ultrasonic sensor, a monocular camera, etc. may also be used as the rangefinder S2.

The hydraulic excavator is not equipped with angle sensors to measure the angles of the boom, arm, and bucket, or inclination sensors to measure the inclination of the vehicle body 1, but these sensors may be installed in the hydraulic excavator.

Figure 4 and other figures show an example of a display in which the measurement range is divided into multiple meshes, but the size of each mesh can be changed as appropriate within the constraints of the pitch of the point cloud data of the measurement points obtained by the rangefinder S2. The smaller the mesh, the higher the resolution at which the measurement data can be displayed. The aspect ratio of the mesh can also be changed.

In addition, while Figure 9 and other figures show an example in which the unmeasurable area A is displayed in white, the unmeasurable area A may also be displayed by filling it with a specific color or pattern (black, hatching, etc.). The same applies to the unmeasurable area A' (Figure 20).

1...Vehicle body, 2...Front implement, 11...Driver's cab, 15...Monitor, 22...Boom, 23...Arm, 24...Bucket, 28...Reflector, 30...Controller, 32...Memory, 42...Terrain measurement button, A, A'...Unmeasurable area, CL...Current terrain, dH...Difference from most recent measurement data, dH1...Set value, DL...Design terrain, IA...Slope amount, H...Difference between design terrain data and measurement data of current terrain, P1-P6...Distance measurement point, S1...Position sensor, S2...Distance meter, T...Elapsed time, T1...Set time, V...Vehicle speed, V1...Set speed, W...Horizontal interval, W1...Set interval

Claims (11)

a vehicle body having a driver's cab;
a front working implement attached to the vehicle body;
a monitor provided in the driver's cab;
a rangefinder for measuring distances to a plurality of measurement points on the current terrain around the vehicle body;
a controller that divides the periphery of the vehicle body into a plurality of meshes and displays the measurement data of the current topography based on the output of the rangefinder on the monitor for each mesh ,
The controller
calculating horizontal coordinates of the plurality of distance measurement points based on the output of the rangefinder;
calculating a horizontal distance between each of the plurality of distance measuring points and an adjacent distance measuring point;
A hydraulic excavator characterized in that, for areas where the horizontal spacing between adjacent measurement points is less than a set spacing set based on the size of the mesh , height data calculated based on the output of the rangefinder is displayed on the monitor as measurement data of the current terrain for each mesh , and for areas where the horizontal spacing between adjacent measurement points is greater than the set spacing, the meshes where no measurement points exist are displayed on the monitor as unmeasurable areas where measurement is not possible. The hydraulic excavator according to claim 1,
a position sensor for acquiring position data of the vehicle body;
The controller stores map data of the construction site,
The controller
based on the vehicle body position data acquired by the position sensor, the coordinate data of the plurality of distance measurement points measured by the rangefinder is associated with the map data;
Displaying the map data on the monitor;
For areas of the map data displayed on the monitor where the horizontal distance between adjacent measuring points is less than the set distance, height data calculated based on the output of the rangefinder is overlaid and the measurement data of the current topography is displayed, and for areas of the map data displayed on the monitor where the horizontal distance between adjacent measuring points is greater than the set distance, a message indicating that the area is an unmeasurable area where measurement is not possible is overlaid. The hydraulic excavator according to claim 2,
The controller stores design terrain data,
The hydraulic excavator is characterized in that the controller displays and outputs a difference between the designed topography data and the measurement data of the current topography on the monitor. The hydraulic excavator according to claim 1,
The front working implement is provided with a reflector that can be detected by the range finder,
The hydraulic excavator is characterized in that the controller stops measuring the current topography when the range finder detects the reflector between the current topography and the range finder. The hydraulic excavator according to claim 1,
The front working implement is provided with a reflector that can be detected by the range finder,
When the rangefinder detects the reflector between the current terrain and the rangefinder, the controller displays on the monitor a message indicating that the front working implement is obstructing measurement of the current terrain. The hydraulic excavator according to claim 4,
The hydraulic excavator is characterized in that the reflector is provided at least at one of the tip end portion of the arm of the front working machine, the base end portion of the bucket, and the longitudinal intermediate portion of the boom. The hydraulic excavator according to claim 1,
a terrain measurement button for instructing measurement of the current terrain by the rangefinder;
The hydraulic excavator is characterized in that the controller calculates measurement data of the current topography and displays it on the monitor in response to a measurement instruction input in response to operation of the topography measurement button. The hydraulic excavator according to claim 7,
The hydraulic excavator is characterized in that the controller calculates the measurement data of the current topography only when the vehicle speed is less than a set speed. The hydraulic excavator according to claim 7,
The controller
The measurement data of the current topography is compared with the most recent measurement data of the corresponding coordinates;
The hydraulic excavator is characterized in that the measurement data is updated only for distance measurement points where the difference from the most recent measurement data is equal to or greater than a set value. The hydraulic excavator according to claim 7,
The controller
The measurement data of the current topography is compared with the most recent measurement data of the corresponding coordinates;
a hydraulic excavator, characterized in that measurement data is updated only for distance measurement points for which the elapsed time from the measurement date and time of the most recent measurement data is equal to or longer than a set time; The hydraulic excavator according to claim 2,
The controller
Calculating the amount of slope of the current topography based on the measurement data of the current topography;
The hydraulic excavator is characterized in that the amount of tilt is displayed on the monitor while being superimposed on the map data.