JP7739072B2 - Work machinery - Google Patents

Description

The present invention relates to a work machine.

Integrated construction machinery, such as hydraulic excavators, uses GNSS to measure its own position coordinates in the Earth's coordinate system. Because some of the positioning satellites used in GNSS orbit the Earth, the accuracy of GNSS position measurements changes from moment to moment due to changes in the position of the positioning satellites. Furthermore, GNSS position measurements contain various error factors. Therefore, when a system using GNSS provides location information to users, it is also necessary to provide information related to the reliability of the positioning.

The following prior art is known for providing users with the reliability of positioning information using GNSS. For example, Patent Document 1 discloses a navigation device equipped with a satellite positioning unit that performs satellite positioning based on radio waves received from satellites, the navigation device comprising: a current position calculation means that calculates a current position based on the position determined by the satellite positioning unit while the satellite positioning unit is capable of performing satellite positioning; a current position estimation means that calculates an estimated current position while the satellite positioning unit is unable to perform satellite positioning, at least until the estimated current position reaches an intersection; and a guide image display means that displays a guide image on a map in which a mark indicating the current position of the navigation device is placed, the current position estimation means sequentially calculating the estimated current position from the current position calculated by the current position calculation means immediately before the satellite positioning unit became unable to perform satellite positioning, and displaying the estimated current position on a road where the current position calculated by the current position calculation means immediately before the satellite positioning unit became unable to perform satellite positioning is located. The navigation device calculates the estimated current position by moving the satellite positioning unit at a predetermined speed in the direction of travel immediately before satellite positioning becomes impossible, and the guide image display means places the mark on the map at a position corresponding to the current position calculated by the current position calculation means during a period when the satellite positioning unit is able to perform satellite positioning; places the mark on the map at a position corresponding to the estimated current position calculated by the current position estimation means during a period from when the satellite positioning unit becomes unable to perform satellite positioning until the estimated current position calculated by the current position estimation means reaches an intersection; and places the mark on the map at a position corresponding to the intersection reached during a period after the estimated current position calculated by the current position estimation means reaches an intersection during a period when satellite positioning is impossible.

Japanese Patent Application Laid-Open No. 2014-137313

In information-based construction, the accuracy of construction work by work machines such as hydraulic excavators is greatly affected by positioning accuracy. For this reason, users of work machines need to take the positioning accuracy of the work machine into consideration when planning work. However, because the positioning accuracy of GNSS varies depending on the positions of the work machine and positioning satellites at the work site, the work site environment, and other factors, it is not easy to plan work appropriately. Furthermore, if work planning cannot be done appropriately, there is a concern that the efficiency of the entire construction work will decrease.

The present invention was made in consideration of the above, and aims to provide a work machine that can assist in work planning by appropriately providing information related to GNSS positioning accuracy to the work machine user, thereby improving the efficiency of the entire construction project.

The present application includes multiple means for solving the above-mentioned problems, and one example thereof includes a lower traveling body, an upper rotating body that is rotatably mounted on the lower traveling body and that constitutes a vehicle body together with the lower traveling body, a working device that is rotatably supported on the upper rotating body and that is configured by rotatably connecting multiple driven members including a work implement to each other, an attitude information measuring device that measures attitude information of the upper rotating body and the multiple driven members, a position measuring device that calculates the position and orientation of the vehicle body at a construction site based on navigation signals from a positioning satellite, and a design design that is a target shape of the construction site based on the calculation results from the position measuring device and the attitude information from the attitude information measuring device. In a construction machine equipped with a controller that calculates the distance between a work target surface obtained from design data and a work implement attached to the tip of the work device, the controller divides the construction site into multiple areas based on the design data, sets a representative position for each of the multiple divided areas, calculates the positioning accuracy of the position measurement device for each of the representative positions of the multiple areas based on the orbital information of the positioning satellites, topographical data for the surrounding area including the construction site, and structure data indicating the position and shape of structures included within the range of the topographical data, and generates a positioning reliability map that links the positioning accuracy with the representative position of each of the multiple areas.

According to the present invention, by appropriately providing information related to the positioning accuracy of GNSS to users of work machines, it is possible to support work planning and improve the efficiency of the entire construction work.

1 is a diagram schematically illustrating the appearance of a hydraulic excavator, which is an example of a work machine. FIG. 2 is a functional block diagram illustrating the relevant configuration of a machine guidance system extracted from the control system that controls the overall operation of the hydraulic excavator. FIG. 1 is a diagram illustrating an example of an external system that functions as a reference station. FIG. 2 is a functional block diagram illustrating the processing functions of the machine guidance unit together with related configurations including some functions of the GNSS receiver. FIG. 2 is a functional block diagram illustrating the processing functions of a positioning reliability calculation unit together with related configurations including some functions of the GNSS receiver. FIG. 2 is a functional block diagram illustrating the processing functions of a self-position reliability calculation unit together with related configurations including some functions of a GNSS receiver. FIG. 2 is a functional block diagram showing the processing function of a construction information recording unit. 10 is a flowchart showing the processing content of a representative position coordinate acquisition unit. 10 is a flowchart showing the processing contents of a structure and topography data acquisition unit. 10 is a flowchart showing the processing contents of a visible satellite identifying unit, a positioning accuracy calculating unit, and a positioning reliability map generating unit. 10 is a flowchart showing the processing contents of a self-location reliability calculation unit. 10 is a flowchart showing the processing contents of a construction information recording unit. FIG. 10 is a diagram showing an example of a display of a positioning reliability map on a display device. FIG. 10 is a diagram showing an example of a display of an estimated vertical error on a display device.

Embodiments of the present invention will be described below with reference to the drawings. Note that in this embodiment, a hydraulic excavator equipped with a front working implement will be described as an example of a work machine, but this is not limited to this, and the present invention can also be applied to other work machines that perform work using positioning results from GNSS or the like.

Figure 1 is a diagram showing a schematic view of the exterior of a hydraulic excavator 1, which is an example of a work machine according to this embodiment. Figure 2 is a functional block diagram showing the relevant components of a machine guidance system 200, which is part of a control system that controls the overall operation of the hydraulic excavator 1.

In Figure 1, the hydraulic excavator 1 comprises an articulated front working machine (working device) 5 formed by connecting multiple driven members (boom 6, arm 7, bucket 8) that each rotate vertically, and an upper rotating body 3 and a lower traveling body 2 that form the vehicle body, with the upper rotating body 3 being rotatable relative to the lower traveling body 2.

The base end of the boom 6 of the front work implement 5 is supported on the front part of the upper rotating body 3 so as to be rotatable in the vertical direction, one end of the arm 7 is supported on an end (tip) different from the base end of the boom 6 so as to be rotatable in the vertical direction, and a bucket 8 is supported on the other end of the arm 7 so as to be rotatable in the vertical direction. The boom 6, arm 7, bucket 8, upper rotating body 3, and lower traveling body 2 are each driven by hydraulic actuators: a boom cylinder 9, an arm cylinder 10, a bucket cylinder 11, a swing motor (not shown), and left and right traveling motors (not shown).

Inertial Measurement Units (IMUs) 21 to 24 are respectively disposed on the vehicle body (specifically, the upper rotating body 3), boom 6, arm 7, and bucket 8. Hereinafter, when it is necessary to distinguish between these IMUs 21 to 24, they will be referred to as the vehicle body IMU 21, boom IMU 22, arm IMU 23, and bucket IMU 24, respectively.

The inertial measurement units 21-24 measure angular velocity and acceleration. Assuming that the upper rotating body 3 and driven members 6-8 on which the inertial measurement units 21-24 are mounted are stationary, the orientation (ground angle) of the upper rotating body 3 and driven members 6-8 can be detected as attitude information based on the direction of gravitational acceleration (i.e., the vertical downward direction) in the IMU coordinate system set in the inertial measurement units 21-24 and the mounting state of the inertial measurement units 21-24 (i.e., the relative positional relationship between the inertial measurement units 21-24 and the upper rotating body 3 and driven members 6-8).

The detection results of the inertial measurement unit 21 can be used to calculate the forward/backward tilt angle (pitch angle) and left/right tilt angle (roll angle) of the upper rotating body 3. Furthermore, the detection results of the inertial measurement units 21-24 can be used to calculate the relative angles of the upper rotating body 3 and the driven members 6-8, i.e., the rotation angle of the boom 6 relative to the upper rotating body 3 (boom angle), the rotation angle of the arm 7 relative to the boom 6 (arm angle), and the rotation angle of the bucket 8 relative to the arm 7 (bucket angle). Furthermore, the rotation angle of the upper rotating body 3 can be detected based on the angular velocity detected by the inertial measurement unit 21. In other words, the inertial measurement units 21-24 can also be considered angle detectors that detect the relative angles of the upper rotating body 3 and the driven members 6-8. An angle detection device may be used instead of the inertial measurement units 21-24 at the rotating portion of the upper rotating body 3 or the connection portion of the driven members 6-8. Here, the inertial measurement units 21 to 24 constitute a posture information measurement device that measures and outputs posture information, which is information related to the posture of the hydraulic excavator 1.

The operator's cab 4, where the operator sits, is located at the top front of the upper rotating body 3. The cab 4 is equipped with multiple operating levers (not shown) that output operation signals to operate multiple hydraulic actuators (boom cylinder 9, arm cylinder 10, bucket cylinder 11, swing motor, and travel motor), each assigned to operate one of the multiple hydraulic actuators.

The operator's cab 4 is also equipped with a display device 36 that has the function of notifying the operator of information and allowing the operator to input information. The screen of the display device 36 is provided with, for example, a touch panel formed on the surface, and this touch panel's function allows it to accept input from the operator.

Two GNSS antennas 31, 32 for positioning using the Global Navigation Satellite System (GNSS) are located on top of the upper rotating body 3, for example, behind the driver's cab 4. The GNSS antennas 31, 32 receive navigation signals output from positioning satellites flying above and send them to the GNSS receiver 33 (see Figure 2). The GNSS receiver 33 calculates the positions of the GNSS antennas 31, 32 in the Earth coordinate system based on the navigation signals received by the GNSS antennas 31, 32 and outputs this as position information. Note that the site coordinate system set at the construction site can be easily converted to the Earth coordinate system, and a position in the Earth coordinate system can be said to be synonymous with a position in the site coordinate system.

Because the relative positions of the GNSS antennas 31, 32 with respect to the upper rotating body 3 are fixed and known, the position of the hydraulic excavator 1 in the Earth coordinate system can be calculated from the position information measured by the GNSS antennas 31, 32. Furthermore, the direction vector between the GNSS antennas 31, 32 can be calculated from the deviation of the position information measured by the two GNSS antennas 31, 32, and the orientation of the upper rotating body 131 can be calculated.

Here, the GNSS receiver 33, which includes the GNSS antennas 31 and 32, constitutes a position measurement device that measures the position of the hydraulic excavator 1, which is a work machine, at a construction site and outputs the measurement results as position information.

Furthermore, for example, a radio 34 is located on the upper rear side of the driver's cab 4 to receive correction data (hereinafter referred to as RTK correction data) used for RTK (Real Time Kinematic) positioning from a reference station.

Figure 3 shows an example of an external system 38 that functions as a reference station.

As shown in Figure 3, the external system 38 includes a GNSS antenna 39 for positioning using GNSS, a GNSS receiver 40 that calculates the position of the GNSS antenna 39 in the Earth coordinate system based on the navigation signal received by the GNSS antenna 39 and generates RTK correction data based on the position of the GNSS antenna 39 indicated by the calculation result and the position of the GNSS antenna 39 that has been measured separately in advance with high accuracy, and a radio 41 that outputs the RTK correction data generated by the GNSS receiver 40 via a radio antenna 41a.

As shown in Figure 2, the machine guidance system 200 is composed of a GNSS receiver 33, a radio 34, a controller 35, a display device 36, inertial measurement units 21-24, and their associated components. An external storage medium (storage device) 37 is also connected to the controller 35. The external storage medium (storage device) 37 stores three-dimensional design data representing the target shape of the construction site, three-dimensional topographical data for the surrounding area including the construction site, and three-dimensional structure data indicating the position and shape of structures other than the topography included within the three-dimensional topographical data.

The machine guidance system 200 is equipped with a controller 35 that calculates the position and attitude of the hydraulic excavator 1, the tip position of the work implement (bucket 8), etc. based on RTK correction data received from a reference station by the radio antenna 34a of the radio 34, position and orientation information calculated by the GNSS receiver 33 based on navigation signals received from positioning satellites by the GNSS antennas 31 and 32, attitude information from the inertial measurement units 21 to 24, and information stored in an external storage medium 37. The controller 35 calculates, for example, the distance between the work target surface and the bucket 8, and outputs the calculation results to the display device 36 for display.

Although not shown, the controller 35 is hardware equivalent to a computer that includes a CPU (Central Processing Unit) as a processing device, and a storage device (e.g., semiconductor memory such as ROM or RAM, or a hard disk drive) that stores programs executed by the processing device and data necessary for executing the programs. Note that if the controller 35 is configured using integrated circuits such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array), some or all of the functions of the controller 35 may be realized by these integrated circuits.

The controller 35 includes a machine guidance unit 35a that calculates the positional relationship between the position and attitude of the hydraulic excavator 1 and the three-dimensional design data, and provides work support to the operator; a positioning reliability calculation unit 35b that calculates the reliability of GNSS positioning for the entire construction site; a self-position reliability calculation unit 35c that calculates the reliability of GNSS positioning for the position of the hydraulic excavator 1; and a construction information recording unit 35d that records the position coordinate data of the tip of the hydraulic excavator's 1 bucket 8 and the reliability data of the GNSS positioning in association with each other.

Figure 4 is a functional block diagram illustrating the processing functions of the machine guidance unit 35a along with related configuration, including some functions of the GNSS receiver 33.

In Figure 4, the GNSS receiver 33 has an RTK correction data receiving unit 100 that receives RTK correction data via the radio 34, a satellite signal receiving unit 101 that receives navigation signals via the GNSS antennas 31 and 32, a satellite selecting unit 102 that selects a positioning satellite to use for position calculation based on the satellite signal strength and satellite position, etc., and a GNSS position/vector calculating unit 103 that calculates the position of the GNSS antenna 31 and the vector from the GNSS antenna 31 to the GNSS antenna 32.

Also, in FIG. 4, the machine guidance unit 35a includes a vehicle body attitude calculation unit 104 that calculates the attitude of the vehicle body based on attitude information from the inertial measurement unit 21 provided on the vehicle body, a front attitude calculation unit 105 that calculates the attitude of the front work implement 5 based on attitude information from the inertial measurement units 22 to 24 provided on the front work implement 5, a three-dimensional design data acquisition unit 106 that acquires three-dimensional design data (target shape of the construction site) 37a stored in an external storage medium 37, a vehicle body position and attitude calculation unit 107 that calculates the position and attitude of the vehicle body in the site coordinate system based on the calculation results from the GNSS receiver 33 and the calculation results from the vehicle body attitude calculation unit 104, and a front attitude calculation unit 105 that calculates the position and attitude of the vehicle body in the site coordinate system based on the calculation results from the vehicle body position and attitude calculation unit 107 and the front attitude calculation unit 105. a cross section calculation unit 109 that calculates a cross section of the three-dimensional design data 37a on a work plane that is set to include the front work implement 5, based on information from the position and attitude integration unit 108 and information from the three-dimensional design data acquisition unit 106; and a distance calculation unit 110 that calculates the distance between the work target plane obtained from the three-dimensional design data and the front work implement 5 (specifically, the distance between the work target plane and the toe of the bucket 8) based on information from the position and attitude integration unit 108 and the calculation results from the cross section calculation unit 109, and displays the distance on the display device 36.

The machine guidance unit 35a requires highly accurate position information, and therefore uses position information calculated by RTK positioning performed by the GNSS receiver 33. The RTK correction data receiving unit 100 receives, via the radio 34, RTK correction data generated by the reference station (external system) 38 and transmitted at regular intervals.

The GNSS receiver 33 performs RTK positioning of the three-dimensional position of antenna 31 and the vector from antenna 31 to antenna 32 based on the RTK correction data received via the radio 34 and the signals from positioning satellites received by the GNSS antennas 31 and 32. This RTK positioning allows the three-dimensional position of antenna 31 and the vector from antenna 31 to antenna 32 to be measured with high accuracy.

The controller 35 performs general vector calculations and coordinate transformations based on the various input data to calculate the position and posture of the hydraulic excavator 1 and the three-dimensional position of the tip of the bucket 8. Furthermore, based on the position and posture of the hydraulic excavator 1 and the three-dimensional design data 37a input from the external storage medium 37, it calculates the cross-sectional shape of the three-dimensional design data 37a and the distance between the tip of the bucket 8 and the target surface.

By outputting the calculation results from the controller 35 to the display device 36, the operator can refer to the highly accurately measured positional relationship between the hydraulic excavator 1 and the three-dimensional design data, enabling soil shaping work to be carried out with high quality.

Figure 5 is a functional block diagram illustrating the processing functions of the positioning reliability calculation unit 35b together with related configuration including some functions of the GNSS receiver 33.

In FIG. 5, the GNSS receiver 33 has a satellite orbit information receiving unit 111 that receives satellite orbit information for each positioning satellite via the radio 34. The satellite orbit information receiving unit 111 receives, via the radio 34, satellite orbit information that is stored in the GNSS receiver 40 of the reference station (external system 38) and transmitted via the radio 41, for example.

Also, in FIG. 5, the positioning reliability calculation unit 35b includes a structure/terrain data acquisition unit 112 that acquires structure position/shape data (i.e., three-dimensional terrain data, three-dimensional structure data) 37b stored in the external storage medium 37 and integrates it with current terrain data 300 that represents the current terrain of the construction site, which is stored sequentially; a three-dimensional design data acquisition unit 106 (a functional unit shared with the machine guidance unit 35a, etc.) that acquires three-dimensional design data (target shape of the construction site) 37a stored in the external storage medium 37; and a three-dimensional design data acquisition unit 106 that divides the construction site into multiple areas (blocks) of predetermined size based on the coordinate range of the three-dimensional design data 37a acquired by the three-dimensional design data acquisition unit 106, and calculates the coordinates of the multiple divided areas. The system includes a representative position coordinate acquisition unit 113 that acquires a representative position (e.g., center of gravity position) for each of the multiple areas; a visible satellite identification unit 114 that identifies visible satellites (i.e., positioning satellites that can receive navigation signals at the representative positions) at any time at the representative positions of each of the multiple areas acquired by the representative position coordinate acquisition unit 113 based on the structure position/shape data 37b and satellite orbit information; a positioning accuracy calculation unit 115 that calculates information related to the positioning accuracy of the GNSS receiver 33 for the visible satellites identified by the visible satellite identification unit 114 based on the structure position/shape data 37b and satellite orbit information obtained via the visible satellite identification unit 114 (e.g., position dilution of precision (PDOP), which is one of the accuracy indicators) for each of the representative positions of the multiple areas; and a positioning reliability map generation unit 116 that generates a positioning reliability map that links the information related to the positioning accuracy (e.g., position dilution of precision (PDOP)) with the representative positions of the multiple areas and outputs it to the display device 36 for display.

Figures 8 to 10 are flowcharts showing the processing content of the positioning reliability calculation unit 35b. Figure 8 is a flowchart showing the processing content of the representative position coordinate acquisition unit. Figure 9 is a flowchart showing the processing content of the structure and terrain data acquisition unit 112. Figure 10 is a flowchart showing the processing content of the visible satellite identification unit, positioning accuracy calculation unit, and positioning reliability map generation unit.

The positioning reliability calculation unit 35b obtains in advance via the GNSS receiver 33 the satellite positions at representative positions in each area in order to calculate the reliability of GNSS positioning for the entire construction site, which is the working area of the hydraulic excavator 1.

As shown in FIG. 8, the positioning reliability calculation unit 35b first acquires the three-dimensional design data 37a (step S100), divides the planar coordinates (= work area) of the three-dimensional design data 37a into regions of a predetermined size, and acquires the coordinates of the representative position of each region (step S110).

Also, as shown in FIG. 9, the positioning reliability calculation unit 35b acquires structure position and shape data (i.e., three-dimensional terrain data, three-dimensional structure data) 37b (step S200). To identify visible satellites at each representative position, information on obstacles that block positioning satellite signals is required. At a construction site, obstacles are structures around the site and the site's topography. Data on these obstacles is acquired in different ways, and since structures around the site do not change significantly from day to day, the controller 35 can acquire this information by storing structure position and shape data 37b, which indicates the structure's position and shape data, in the external storage medium 37.

The controller 35 also reads and acquires the current terrain data 300 stored in a memory area (not shown) (step S210). Because the terrain at the work site changes from moment to moment depending on the work being done, the position data of the tip of the bucket 8 of the hydraulic excavator 1 is stored as the current terrain data 300 in the controller 35.

Next, the structure position/shape data 37b and the current topography data 300 are integrated (step S220). By integrating the information in this way, it is possible to obtain information on the shape and position of obstacles that may block navigation signals from the positioning satellite at each representative position within the construction site.

Also, as shown in FIG. 10, the positioning reliability calculation unit 35b acquires satellite orbit information (step S300). To acquire the satellite position at each work location, satellite orbit information for all positioning satellites is acquired from the external system 38 via the radio 34 of the GNSS receiver 33. Here, satellite orbit information is information indicating the flight start of each positioning satellite and its position at each time in the past and future, and is information that has been identified and made public in advance by the administrator of the positioning satellite, etc. Note that because each positioning satellite orbits the Earth at a regular interval, satellite orbit information for several hours into the future (time series data on satellite positioning) can also be acquired in advance.

Next, visible satellites at each representative position are identified from the positioning satellite location information, the coordinates of each representative position, and obstacle shape data (step S310).

In this embodiment, if there are no obstacles on the line connecting the representative positions of multiple areas and the position of a positioning satellite, that positioning satellite is considered a visible satellite. For example, if the position of a positioning satellite is Pi, the work position is pi, the normal of a face that makes up the shape of an obstacle is n, and the vertices are a, b, and c, then it can be determined whether the positioning satellite is a visible satellite by performing an intersection detection using the following (Equations 1) to (Equations 3).

Here, R(t) is the coordinate of the intersection point where a surface constituting the shape of the obstacle intersects with the line from satellite Pi to work position pi, and t represents the distance from satellite Pi to intersection point R(t). Furthermore, u and v are variables used to determine whether intersection point R(t) exists inside the surface.

Next, the position dilution of precision (PDOP) for each representative position is calculated using the position information of visible satellites (step S320).

Position Dilution of Precision (PDOP) is widely used as an indicator of GNSS positioning accuracy due to satellite positioning, and can be calculated using the following formula (Equation 4):

Here, σxx^2, σyy^2, and σzz^2 in the above (Equation 4) can be calculated using the following (Equation 5) and (Equation 6).

Equations 5 and 6 above use the trace of the covariance matrix G, which is calculated from the geometric relationship between the satellite position and the work position. Note that EL and AZ in equation 6 above are the elevation angle and azimuth angle, respectively, that represent the satellite position.

Next, the positioning reliability map is generated by linking the positioning dilution of precision (PDOP) of each representative position obtained with each of the multiple regions (step S330). Note that by using time-series satellite positioning data (satellite orbit information), the positioning dilution of precision (PDOP) can be calculated using a similar procedure to calculate not only the current value but also the value several hours from now. In other words, a positioning reliability map can be generated for any date and time.

Figure 13 shows an example of a positioning reliability map displayed on the display device 36.

As shown in FIG. 13, the display device 36 displays an overhead view 123 of the three-dimensional design data 37a at the construction site, superimposed on it, with a shovel icon 124 indicating the position and orientation of the hydraulic excavator 1 at the construction site. The shovel icon 124 is drawn based on, for example, the position and orientation of the hydraulic excavator 1 output from the machine guidance unit 35a, so the positional relationship between the overhead view 123 of the three-dimensional design data 37a and the shovel icon 124 is displayed correctly. Furthermore, a reliability map 125 is superimposed on the overhead view 123 of the three-dimensional design data 37a, and the positional accuracy degradation rate (PDOP) of the representative position of each region (block) is depicted using, for example, color information corresponding to the positional accuracy degradation rate. In this embodiment, the positional accuracy degradation rate is illustrated by hatching or the like. In addition, a time adjustment bar 126 is displayed, and by operating 126a of the time adjustment bar 126, the operator can switch the display to a positioning reliability map that reflects the position dilution of precision (PDOP) at a certain point in time several hours from now (any time).

As described above, operators can know the reliability of satellite positioning at each location across the entire construction site, both now and several hours from now (at any time), allowing them to consider the optimal setup (route to work locations) and improve work efficiency.

Figure 6 is a functional block diagram showing the processing functions of the self-position reliability calculation unit 35c together with related configuration including some functions of the GNSS receiver 33.

In Figure 6, the GNSS receiver 33 has a position dispersion calculation unit 117 that calculates the position dispersion (position dispersion data) of the antenna 31.

Also, in FIG. 6, the self-position reliability calculation unit 35c includes a position variance acquisition unit 118 that acquires position variance data from the GNSS receiver 33, a three-dimensional design data acquisition unit 106 that acquires three-dimensional design data (target shape of the construction site) 37a stored in the external storage medium 37, a vehicle body position and attitude calculation unit 107 that calculates the position and attitude of the vehicle body in the site coordinate system based on the calculation results from the GNSS receiver 33 and the calculation results from the vehicle body attitude calculation unit 104, a position and attitude integration unit 108 that integrates the calculation results from the vehicle body position and attitude calculation unit 107 and the calculation results from the front attitude calculation unit 105 and outputs the position and attitude of the entire hydraulic excavator 1 including the front work implement 5 in the site coordinate system, and The system includes a target surface acquisition unit 119 that acquires a target surface to be worked on by the hydraulic excavator 1 from among the many surfaces constituting the three-dimensional design data 37a, based on the acquired three-dimensional design data 37a and the position and orientation information of the hydraulic excavator 1 integrated by the position and orientation integration unit 108, and an estimated vertical error calculation unit 120 that calculates an estimated vertical error, which is the error in the vertical (height) position of the working implement (bucket 8) relative to the target surface (error in the distance between the target surface and the bucket), based on the position variance data acquired by the position variance acquisition unit 118, the target surface acquired by the target surface acquisition unit 119, and the vehicle body position and orientation calculated by the vehicle body position and orientation calculation unit 107 (i.e., the direction vector of the hydraulic excavator 1 calculated by the machine guidance unit 35a). Note that the three-dimensional design data acquisition unit 106, vehicle body position and orientation calculation unit 107, and position and orientation integration unit 108 are functional units shared with the machine guidance unit 35a, etc.

Figure 11 is a flowchart showing the processing performed by the self-location reliability calculation unit 35c.

The self-position reliability calculation unit 35c is a functional unit that calculates the impact of the GNSS positioning accuracy on the excavation accuracy of the target surface of the hydraulic excavator 1 as an error in the vertical direction, which is the excavation direction.

As shown in FIG. 11, the self-position reliability calculation unit 35c first acquires the three-dimensional design data 37a (step S400), acquires the tip position of the bucket 8 (step S410), and, from this information, identifies the target surface that is the current work target of the hydraulic excavator 1 from the three-dimensional design data 37a composed of multiple surfaces, and acquires data on the target surface (step S420). Note that while this embodiment illustrates a case in which the system automatically identifies the target surface, it may also be configured so that the operator manually selects it.

When performing excavation work, the tip of the bucket 8 of the hydraulic excavator 1 is located on the target surface, so the target surface that is the current work target can be identified by determining whether a line drawn vertically from the position of the tip of the bucket 8 intersects with the surfaces that make up the three-dimensional design data 37a. Identifying the target surface can be achieved by substituting the above (Equations 1) to (Equations 3), in the same way as determining whether a satellite signal intersects with an obstacle. Note that for adjacent surfaces adjacent to the identified target surface, if the normal vector of the target surface matches the normal vector of the adjacent surface, the adjacent surface is treated as part of the target surface.

Next, the direction vector of the hydraulic excavator 1, the target surface of the work object, and the position dispersion data of the antenna 31 calculated by the GNSS receiver 33 are acquired (step S430), and an estimated vertical error representing the reliability of satellite positioning at the current position of the hydraulic excavator 1 is calculated (step S440).

The estimated vertical error is calculated using the following (Equation 7) and (Equation 8).

First, the horizontal error Eh is calculated using the horizontal variances σxx and σyy using Equation 7 above. The error Eh is the 2DRMS, which is a commonly used index. Next, the estimated vertical error Ed in the distance between the bucket 8 and the target surface is calculated using Equation 8 above, using the vertical variance σzz and the horizontal error Eh calculated using Equation 7 above. The gradient θm of the target surface is the ground angle between the plane passing through the front work implement 5 (boom 6, arm 7, bucket 8) and the target surface.

In the above (Equation 7) and (Equation 8), the distance between the bucket 8 and the target surface is calculated using the horizontal position variance and vertical position variance, but the GNSS receiver 33 also calculates the azimuth angle and azimuth angle variance from the vector (baseline vector) between the antennas. Therefore, when calculating the estimated vertical error Ed of the vertical distance between the bucket 8 and the target surface, the error in the horizontal position of the bucket 8 may be calculated using the azimuth angle variance in addition to the horizontal position variance.

Figure 14 shows an example of the display of the estimated vertical error on the display device 36.

As shown in Figure 14, the display device 36 displays numerical information 127 output by the machine guidance unit 35a indicating the distance from the tip of the bucket 8 to the target surface, and a light bar 128 indicating the distance using display area and color.

The estimated vertical error 129 output from the self-position reliability calculation unit 35c is displayed in addition to the numerical information 127 representing the distance. Although not shown, the color information of the light bar 128 may be changed depending on the magnitude of the estimated vertical error.

With the above configuration, the operator can determine how much reliability they should have in the distance information from the tip of the bucket 8 to the target surface. Furthermore, if the estimated vertical error exceeds the accuracy required at the construction site, they can check the reliability map output by the positioning reliability calculation unit 35b and reconsider the construction arrangements.

Figure 7 is a functional block diagram showing the processing functions of the construction information recording unit 35d.

In FIG. 7, the construction information recording unit 35d includes a position and attitude integration unit 108 that integrates the calculation results from the vehicle body position and attitude calculation unit 107 and the front attitude calculation unit 105 to output the position and attitude of the entire hydraulic excavator 1 including the front work implement 5 in the on-site coordinate system; an estimated vertical error calculation unit 120 that calculates an estimated vertical error of the implement (bucket 8) relative to the target plane based on the position variance data acquired by the position variance acquisition unit 118, the target plane acquired by the target plane acquisition unit 119, and the vehicle body position and attitude calculated by the vehicle body position and attitude calculation unit 107 (i.e., the direction vector of the hydraulic excavator 1 calculated by the machine guidance unit 35a); and an estimated vertical error calculation unit 120 that calculates an estimated vertical error of the implement (bucket 8) relative to the target plane based on the structure position and shape data 37b and satellite orbit information obtained via the visible satellite identification unit 114, and outputs information related to the positioning accuracy of the GNSS receiver 33 (for example, the position dilution of precision (PDOP) which is one of the accuracy indicators) for the visible satellites identified by the visible satellite identification unit 114. The system includes a positioning accuracy calculation unit 115 that calculates the (Position Precision) for each representative position of a plurality of regions, a current terrain data update determination unit 121 that determines whether to update current terrain data 300 that represents the current shape of the soil and sand at the construction site based on the current position coordinates of the tip of the bucket 8 of the hydraulic excavator 1, and a current terrain and positioning reliability recording unit 122 that also records the reliability of GNSS positioning when updating the current terrain data 300. Note that the position and attitude integration unit 108, positioning accuracy calculation unit 115, and current terrain data 300 are functional units shared with the machine guidance unit 35a, positioning reliability calculation unit 35b, and self-position reliability calculation unit 35c, etc.

Figure 12 is a flowchart showing the processing performed by the construction information recording unit 35d.

The construction information recording unit 35d is a functional unit that measures three-dimensional position data representing the shape of the current terrain that has changed due to the excavation work of the hydraulic excavator 1 using the position coordinates of the tip of the bucket 8, and records the position coordinates of the tip of the bucket 8 in association with the positional dilution rate of precision (PDOP) calculated by the positioning reliability calculation unit 35b and the estimated vertical error output by the self-position reliability calculation unit 35c.

As shown in FIG. 12, first, the construction information recording unit 35d acquires the position coordinate data (referred to as the current position coordinates) of the tip of the bucket 8 calculated by the machine guidance unit 35a (step S500).

Next, current terrain data (referred to as past position coordinates) for the X and Y coordinates of the current position coordinates are obtained (step S510), and the Z coordinate value of the current position coordinates is compared with the Z coordinate value of the past position coordinates to determine whether or not to update the current terrain data 300 (step S520). In step S520, if the Z component of the current position coordinates is smaller than the Z component of the past position coordinates, it is determined that the current terrain data 300 should be updated to the current position coordinates (YES). On the other hand, if the Z component of the current position coordinates is larger than the Z component of the past position coordinates, it is determined that the current terrain data 300 should not be updated to the current position coordinates (NO).

If the determination result in step S520 is YES, i.e., if it is determined that the current terrain data should be updated, the position dilution of precision (PDOP) and estimated vertical error (i.e., positioning reliability) are obtained (step S530), and the current position coordinates and the current position dilution of precision (PDOP) and estimated vertical error (i.e., positioning reliability) are linked to the current terrain data and recorded as current terrain data 300 in a memory area (not shown) of the controller 35 (step S540).

With the above configuration, the construction history information recorded in the controller 35 is output to the external storage medium 37, allowing the operator and construction manager to use the construction history information as operational data for the hydraulic excavator 1. In other words, because they can refer to the current terrain shaped by the hydraulic excavator 1 and the reliability of that shape, they can determine whether or not to use the current terrain data 300 for as-built management, etc.

The effects of this embodiment configured as described above are now explained.

In information-based construction, the accuracy of construction work by hydraulic excavators and other work machines is significantly affected by positioning accuracy. For this reason, work machine users must take the work machine's positioning accuracy into consideration when planning work. However, because GNSS positioning accuracy varies depending on the location of the work machine and positioning satellites at the work site, as well as the work site environment, it is not easy to plan work appropriately. Furthermore, if work planning cannot be done appropriately, there are concerns that the efficiency of the entire construction work will decrease.

In contrast, in this embodiment, the system includes a lower traveling body, an upper rotating body that is rotatably mounted on the lower traveling body and that together with the lower traveling body constitutes a vehicle body, a work device that is configured by rotatably connecting multiple driven members including a work implement to each other and is rotatably supported on the upper rotating body, an attitude information measuring device that measures the attitude information of each of the upper rotating body and the multiple driven members, a position measuring device that calculates the position and orientation of the vehicle body at the construction site based on navigation signals from a positioning satellite, a storage device that stores design data that is the target shape of the construction site, topographical data of the surrounding area including the construction site, and structure data that indicates the position and shape of structures included within the range of the topographical data, and calculation results from the position measuring device and a storage device that stores the calculation results from the attitude information measuring device. In a construction machine equipped with a controller that calculates the distance between a work target surface obtained from design data and a work implement attached to the tip of the work device based on attitude information from the design data, the controller divides the construction site into multiple areas based on the design data, sets a representative position for each of the multiple divided areas, calculates the positioning accuracy of the position measurement device for each representative position of the multiple areas based on positioning satellite orbit information, topographical data, and structure data, and generates a positioning reliability map that links the positioning accuracy with each representative position of the multiple areas.By appropriately providing information related to GNSS positioning accuracy to the user of the construction machine, it is possible to support work setup and improve the efficiency of the entire construction project.

In other words, the reliability of GNSS positioning can be obtained for the entire construction site and the current machine position, combined with the work support information calculated by the machine guidance unit 35a. As a result, the operator can decide whether to continue the current work and consider moving to another work position, improving setup efficiency and ultimately improving the efficiency of the entire work process.

<Additional Notes>
The present invention is not limited to the above-described embodiments, and includes various modifications and combinations within the scope of the gist thereof. Furthermore, the present invention is not limited to those including all of the configurations described in the above-described embodiments, and includes those in which some of the configurations are omitted. Furthermore, the above-described configurations, functions, etc. may be realized in part or in whole by designing them as, for example, integrated circuits. Furthermore, the above-described configurations, functions, etc. may be realized in software by a processor interpreting and executing a program that realizes each function.

1...hydraulic excavator, 2...undercarriage, 3...upper rotating body, 4...operator's cab, 5...front work machine (working device), 6...boom, 7...arm, 8...bucket, 9...boom cylinder, 10...arm cylinder, 11...bucket cylinder, 21-24...inertial measurement unit (IMU), 31, 32...GNSS antenna, 34...radio, 34a...radio antenna, 35...controller, 35a...machine guidance unit, 35b...positioning reliability calculation unit, 35c...self-position reliability calculation unit, 35d...construction information recording unit, 36...display device, 37...external storage medium (storage device), 37a...three-dimensional design data, 37b...structure position/shape data, 38...reference station (external system), 39...GNSS antenna, 40...GNSS receiver, 41...radio, 41a...radio antenna, 100...RTK correction data receiving unit, 101...satellite signal receiving unit, 102...satellite selection unit, 103...GNSS position/vector Torque calculation unit, 104... vehicle body attitude calculation unit, 105... front attitude calculation unit, 106... three-dimensional design data acquisition unit, 107... vehicle body position and attitude calculation unit, 108... position and attitude integration unit, 109... cross-section calculation unit, 110... distance calculation unit, 111... satellite orbit information receiving unit, 112... structure and terrain data acquisition unit, 113... representative position coordinate acquisition unit, 114... visible satellite identification unit, 115... positioning accuracy calculation unit, 116... positioning reliability map generation unit, 117... position distribution Calculation unit, 118...position variance acquisition unit, 119...target surface acquisition unit, 120...estimated vertical error calculation unit, 121...current terrain data update determination unit, 122...current terrain and positioning reliability recording unit, 123...bird's-eye view, 124...shovel icon, 125...reliability map, 126...time adjustment bar, 127...numerical information, 128...light bar, 129...estimated vertical error, 131...upper rotating body, 200...machine guidance system, 300...current terrain data

Claims (5)

a lower running body;
an upper rotating body that is rotatably provided on the lower traveling body and that constitutes a vehicle body together with the lower traveling body;
a working device configured by a plurality of driven members including working implements rotatably connected to one another and rotatably supported on the upper rotating body;
a posture information measuring device that measures posture information of the upper rotating body and the plurality of driven members;
a position measurement device that calculates the position and orientation of the vehicle body at the construction site based on a navigation signal from a positioning satellite;
a controller that calculates a distance between a work target surface obtained from design data that is a target shape of the construction site and a work implement attached to a tip of the work implement based on a calculation result from the position measurement device and posture information from the posture information measurement device,
The controller
Dividing the construction site into a plurality of areas based on the design data;
A representative position is set for each of the divided regions;
Calculating the positioning accuracy of the position measuring device for each representative position of the plurality of areas based on the orbital information of the positioning satellite, topographical data of the surrounding area including the construction site, and structure data indicating the position and shape of structures included in the range of the topographical data;
generating a positioning reliability map that associates the positioning accuracy with each of the representative positions of the plurality of regions ;
determining whether or not to record coordinates of the work tool based on a distance between the work tool disposed at the tip of the work device and the work target surface;
When it is determined that the coordinates of the work implement should be recorded, the coordinates of the work implement are associated with the positioning accuracy and stored in a storage device . a lower running body;
an upper rotating body that is rotatably provided on the lower traveling body and that constitutes a vehicle body together with the lower traveling body;
a working device configured by a plurality of driven members including working implements rotatably connected to one another and rotatably supported on the upper rotating body;
a posture information measuring device that measures posture information of the upper rotating body and the plurality of driven members;
a position measurement device that calculates the position and orientation of the vehicle body at the construction site based on a navigation signal from a positioning satellite;
a controller that calculates a distance between a work target surface obtained from design data that is a target shape of the construction site and a work implement attached to a tip of the work implement based on a calculation result from the position measurement device and posture information from the posture information measurement device,
the position measurement device calculates a position variance, which is a variance of a calculation result of the position of the vehicle body at the construction site;
The controller
Dividing the construction site into a plurality of areas based on the design data;
A representative position is set for each of the divided regions;
Calculating the positioning accuracy of the position measuring device for each representative position of the plurality of areas based on the orbital information of the positioning satellite, topographical data of the surrounding area including the construction site, and structure data indicating the position and shape of structures included in the range of the topographical data;
generating a positioning reliability map that indicates the positioning accuracy and each representative position of the plurality of regions in association with each other;
Calculating an estimated vertical error, which is the accuracy of the position of the work tool in a vertical direction relative to the work target surface, based on the position variance;
determining whether or not to record coordinates of the work tool based on a distance between the work tool disposed at the tip of the work device and the work target surface;
When it is determined that the coordinates of the work implement should be recorded, the coordinates of the work implement and the estimated vertical error are linked and stored in a storage device . 2. The work machine according to claim 1,
The controller generates an overhead view image in which information on the three-dimensional position and orientation of the vehicle body is superimposed on the positioning reliability map, and displays the image on a display device. 2. The work machine according to claim 1,
the position measurement device calculates a position variance, which is a variance of a calculation result of the position of the vehicle body at the construction site;
The working machine is characterized in that the controller calculates an estimated vertical error, which is the accuracy of the position of the working implement in a direction vertical to the work target surface, based on the position variance. 5. The work machine according to claim 4 ,
the controller generates a distance display image that simultaneously displays the distance between the work implement disposed at the tip of the work device and the work target surface, and the estimated vertical error, based on the estimated vertical error, and displays the image on a display device.