Work machine

Abstract

The present invention makes it possible to improve construction quality in construction using a machine control function.　In a hydraulic excavator 1 equipped with a machine control function, a main controller 5 stores a constructed region α; calculates a positioning error of a positioning satellite 41 on the basis of GNSS positioning information received by an antenna 42 and the stored GNSS positioning information; generates a correction target surface Y for correcting a connection state between the constructed region α and a target construction surface adjacent to the constructed region α on the basis of the stored constructed region α and the calculated positioning error; and outputs a command signal to a drive device 241 for a work device 30 to operate along the generated correction target surface Y.

Description

Work machine

[0001] The present invention relates to a work machine used in various construction works.

[0002] Work machines such as hydraulic excavators and wheel loaders perform excavation and leveling using a working device at a construction site such as a road construction site, a building construction site, or a civil engineering construction site. Some work machines have a so-called machine control function in which a construction target surface to be constructed is preset, and a control device semi-automatically controls the working device according to an operator's operation so that the working device operates along this construction target surface.

[0003] Generally, when specifying the positional relationship between the construction target surface and the work machine, GNSS (Global Navigation Satellite System) is widely used. This GNSS has a characteristic that the positioning accuracy changes according to the radio wave reception status. Therefore, when the positioning accuracy decreases, the positional relationship between the construction target surface and the work machine cannot be accurately specified, and unevenness or steps may occur on the construction surface excavated or leveled using the machine control function.

[0004] For example, in Patent Document 1, when the positioning quality of GNSS is good and the smoothing condition that the traveling state of the work machine is in a stopped state is satisfied, the intensity of the smoothing process for GNSS information is switched to strong, and when the smoothing condition is not satisfied, the intensity of the smoothing process for GNSS information is switched to weak, thereby disclosing a technique for eliminating the positioning error of GNSS in a short time.

[0005] Japanese Patent Application Laid-Open No. 2022-186365

[0006] However, the technique described in Patent Document 1 only shortens the time during which the positioning accuracy of GNSS is reduced, and cannot prevent the reduction of the positioning accuracy of GNSS itself. Therefore, it is difficult to eliminate the unevenness and steps on the construction surface caused by the positioning error of GNSS in construction using the machine control function.

[0007] Therefore, an object of the present invention is to provide a work machine capable of improving construction quality in construction using a machine control function.

[0008] To achieve the above objective, the present invention provides a main body, a work device attached to the main body, a drive device for driving the work device, an operating device for operating the work device, a receiving device for receiving positioning information output from a positioning device for measuring the position of the main body, a posture detection device for detecting the posture of the work device, and a construction target surface which is a construction target surface that is stored or input in advance, and the operating device for operating the work device so that the work device operates along the construction target surface based on the stored or inputted construction target surface, the positioning information received by the receiving device, and the posture of the work device detected by the posture detection device. A work machine comprising a control device that controls the drive device based on the operation, wherein the control device stores the completed area that has been constructed, calculates a positioning error in the positioning device based on the positioning information received by the receiving device and the positioning information received by the receiving device a predetermined time earlier, generates a correction target surface that corrects the connection state between the completed area and the construction target surface adjacent to the completed area based on the stored completed area and the calculated positioning error, and outputs a command signal to the drive device for the work device to operate along the generated correction target surface.

[0009] According to the present invention, construction quality can be improved in construction using machine control functions. Other issues, configurations, and effects will be clarified by the following description of embodiments.

[0010] This figure shows an overview of the configuration of a hydraulic excavator and the machine control system according to an embodiment of the present invention. This is a graph showing an example of the time course of GNSS positioning error. This figure explains the connection state between a completed area and a planned area for construction adjacent to the completed area. This is a system configuration diagram showing an example of the machine control system configuration. This is a functional block diagram showing the functions of the main controller. This figure explains an example of a method for calculating positioning error. This figure explains an example of a method for generating a correction target surface. This is a flowchart showing the processing flow executed by the main controller.

[0011] Hereinafter, a crawler-type hydraulic excavator will be described as one embodiment of a work machine according to the present invention.

[0012] <Overall Configuration of Hydraulic Excavator 1> First, the overall configuration of hydraulic excavator 1 will be explained with reference to Figure 1.

[0013] Figure 1 is an external side view showing one example of the configuration of a hydraulic excavator 1 according to an embodiment of the present invention.

[0014] The hydraulic excavator 1 comprises a self-propelled crawler-type vehicle 10, a slewing body 20 mounted above the vehicle 10 so as to be rotatable, and a work device 30 attached to the front of the slewing body 20 for performing tasks such as excavation and leveling. In the hydraulic excavator 1, the vehicle 10 and the slewing body 20 constitute the main body.

[0015] The vehicle body 10 is equipped with a pair of crawlers 11 extending in the front-rear direction of the vehicle body on the left and right sides. The vehicle body is moved by rotating the pair of crawlers 11 in contact with the ground using the driving force of a pair of drive motors (not shown). The pair of drive motors are mounted on the left and right sides of the vehicle body 10, corresponding to the left and right crawlers 11, and by driving them independently of each other, the left and right crawlers 11 can be rotated independently in forward and reverse directions. Note that in Figure 1, only the left crawler 11 of the pair of left and right crawlers 11 is shown.

[0016] The slewing body 20 comprises a base slewing frame 21, an operator's cab 22 where the operator sits, a counterweight 23 that maintains balance with the work equipment 30 to prevent the hydraulic excavator 1 from tilting, and a machine room 24 that houses the equipment necessary to drive the hydraulic excavator 1.

[0017] On the slewing frame 21, the driver's cab 22 is placed on the front left side, the counterweight 23 is placed at the rear end, and the machine room 24 is placed between the driver's cab 22 and the counterweight 23.

[0018] The operator's cab 22 is equipped with an operating device 221 for operating the work device 30, an input display device 222 for inputting and displaying various information related to the hydraulic excavator 1, and a construction surface management device 223 for managing the surface that the hydraulic excavator 1 is working on.

[0019] In this embodiment, the operating device 221 is an electric lever type, and each component constituting the work device 30 operates according to the tilting direction and amount of the lever. Note that the operating device 221 does not necessarily have to be a lever type; there are no particular restrictions as long as it is an electric operating device.

[0020] In this embodiment, the input display device 222 is composed of a touch panel and a monitor, and displays, for example, data relating to the operating status and posture of the hydraulic excavator 1, information relating to the surface that serves as the construction target for the hydraulic excavator 1 (hereinafter referred to as the "construction target surface"), and information relating to the positional relationship between the construction target surface and the work device 30, as well as inputting the dimensions and mass of each part of the work device 30.

[0021] The construction surface management device 223 is electrically connected to the input display device 222 (see Figure 4) and manages and stores information about the construction target surface of the hydraulic excavator 1.

[0022] The machine room 24 is equipped with a drive unit 241 for driving the main body and the work device 30, and an engine 242 as a driving device that generates the power necessary for the operation of the hydraulic excavator 1. Note that the driving device for the hydraulic excavator 1 does not necessarily have to be an engine 242; it could also be an electric motor, for example.

[0023] The drive unit 241 consists of a hydraulic pump driven by the engine 242, a plurality of directional control valves that control the flow (direction and flow rate) of the hydraulic fluid discharged from the hydraulic pump, and a plurality of electromagnetic control valves that control the plurality of directional control valves according to command signals output from the main controller 5 (see Figure 4), which will be described later.

[0024] The working device 30 includes a boom 31 whose base end is rotatably attached to the slewing frame 21, a boom cylinder 31A for driving the boom 31, an arm 32 rotatably attached to the tip of the boom 31, an arm cylinder 32A for driving the arm 32, a bucket 33 rotatably attached to the tip side of the arm 32, and a bucket cylinder 33A for driving the bucket 33.

[0025] The boom cylinder 31A connects the slewing frame 21 and the boom 31, and the extension and retraction of the rod causes the boom 31 to rotate (elevate) vertically relative to the slewing body 20.

[0026] The arm cylinder 32A connects the boom 31 and the arm 32, and the extension and retraction of the rod causes the arm 32 to rotate in the front-rear direction relative to the boom 31.

[0027] The bucket cylinder 33A connects the arm 32 and the bucket 33, and the extension and retraction of the rod causes the bucket 33 to rotate in the front-rear direction relative to the arm 32. The bucket 33 is a work tool used to scoop up loads such as soil and minerals, and to level the ground, and this enables the hydraulic excavator 1 to perform various operations such as excavation and leveling.

[0028] Furthermore, the work device 30 is equipped with a boom posture sensor 34 for detecting the posture of the boom 31, an arm posture sensor 35 for detecting the posture of the arm 32, and a bucket posture sensor 36 for detecting the posture of the bucket 33. These boom posture sensor 34, arm posture sensor 35, and bucket posture sensor 36 constitute one form of a posture detection device for detecting the posture of the work device 30.

[0029] Each of the boom attitude sensor 34, arm attitude sensor 35, and bucket attitude sensor 36 may be equipped with, for example, an IMU (INERTIAL MEASUREMENT UNIT) or an angle sensor that detects the relative angle between each component of the work device 30.

[0030] The hydraulic excavator 1 is equipped with a machine control system that automatically controls the operation of the work device 30 so that it operates along a preset construction target surface. Specifically, the machine control system controls the operation of the work device 30 based on the operation of the control device 221 by the operator so that the bucket 33 does not excavate too deep beyond the construction target surface, or so that the bucket 33 takes an appropriate position relative to the construction target surface.

[0031] When the machine control function is enabled in the hydraulic excavator 1, for example, if the operator performs a cloud operation of the arm 32 in the state shown in Figure 1 (operation in the direction of arrow P shown in Figure 1), the boom 31 will automatically rise and fall (operation in the direction of double arrow Q shown in Figure 1) so that the tip of the bucket 33 moves along the construction target surface (surface X shown by the dashed line in Figure 1). This allows the operator to perform excavation work along the construction target surface without requiring skilled operation.

[0032] Furthermore, when the machine control function is enabled in the hydraulic excavator 1, the movement of the bucket 33 is controlled so that the position of the bucket 33 relative to the construction target surface is kept constant. As a result, the operator can perform excavation work while keeping the bucket 33 in a predetermined position by only controlling the arm 32, without having to perform delicate operations on the bucket 33.

[0033] In this machine control system, calculations are performed regarding the operation control of the work device 30 (mainly the boom 31) relative to the construction target surface, based on the position of the main body of the hydraulic excavator 1.

[0034] In this embodiment, the position (position coordinates) of the hydraulic excavator 1 is measured by GNSS (GLOBAL NAVIGATION SATELLITE SYSTEM).

[0035] Specifically, GNSS comprises a positioning satellite 41 whose position in space is known, and an antenna 42 that receives signals output from the positioning satellite 41. Based on the distance from the positioning satellite 41 to the antenna 42, the position (position coordinates) of the hydraulic excavator 1 is determined. Note that although only one positioning satellite 41 is shown in Figure 1, actual GNSS systems use three or more positioning satellites 41.

[0036] The positioning satellite 41 is one embodiment of a positioning device that measures the position of the main body of the hydraulic excavator 1. The antenna 42 is one embodiment of a receiving device that receives positioning information output from the positioning device. The position of the work device 30 is calculated based on the positioning information corresponding to the position of the main body received by the positioning satellite 41, the dimensions of the vehicle body, and the attitude information of the work device 30.

[0037] In addition to using GNSS, other methods for measuring the position of the hydraulic excavator 1 include using a laser positioning meter or a total station. There are no particular restrictions as long as the positioning device and receiving device can determine the position of the hydraulic excavator 1.

[0038] <GNSS Positioning Errors> Next, we will explain the positioning errors that occur with GNSS, referring to Figures 2 and 3.

[0039] Figure 2 is a graph showing an example of the time course of GNSS positioning error. Figure 3 is a diagram illustrating the connection state between the completed area α and the planned area β adjacent to the completed area α.

[0040] In GNSS, positioning errors can occur due to factors such as the strength of the radio waves emitted from the positioning satellite 41 and received by the antenna 42, the effects of radio interference due to multipath, and the position of the positioning satellite 41. As shown in Figure 2, the GNSS positioning error changes sequentially in the positive and negative directions over time, with zero positioning error (no positioning error) as the baseline.

[0041] Due to GNSS positioning errors, the construction target surface recognized by the hydraulic excavator 1 based on the positioning information previously received and stored by the antenna 42 may differ from the construction target surface recognized by the hydraulic excavator 1 based on the positioning information currently received by the antenna 42, even if the same construction target surface information is used, when viewed from the perspective of the construction site.

[0042] In the machine control system, the working device 30 is controlled based on the construction target surface recognized by the hydraulic excavator 1. Therefore, as shown in FIG. 3, based on the positioning information received and stored by the previous antenna 42, the construction target surface recognized by the hydraulic excavator 1 (surface X1 shown by a broken line in FIG. 3) and the construction target surface recognized by the hydraulic excavator 1 based on the positioning information received by the antenna 42 this time (surface X2 shown by a dashed-dotted line in FIG. 3), if there is an error between them, a step S (concavity and convexity) will occur at the boundary between the constructed area α and the planned construction area β adjacent to the constructed area α.

[0043] By offsetting the construction target surface, it is also conceivable to align the height of the construction target surface X1 recognized by the hydraulic excavator 1 based on the positioning information received and stored by the previous antenna 42 and the height of the construction target surface X2 recognized by the hydraulic excavator 1 based on the positioning information received by the antenna 42 this time. However, in this case, if the positioning error of GNSS is large, the positioning error will propagate to the planned construction area β and the construction accuracy will deteriorate, which is not desirable.

[0044] In FIG. 3, since a horizontal surface is taken as an example of the construction target surface of the hydraulic excavator 1, the step S due to the positioning error of GNSS is only in the height direction. However, when the construction target surface is a normal surface or a vertical surface, the step S due to the positioning error of GNSS will be in the horizontal direction or the vertical direction.

[0045] In addition, as a method for measuring the position of the hydraulic excavator 1, in addition to the method using GNSS, for example, there are methods using a laser rangefinder or a total station. However, even with these methods, positioning errors may occur due to the received intensity of laser light, installation errors of transceivers, etc., similar to GNSS.

[0046] <Machine control system configuration> Next, the configuration of the machine control system related to the hydraulic excavator 1 will be described with reference to FIG. 4.

[0047] FIG. 4 is a system configuration diagram showing an example of the configuration of the machine control system.

[0048] The machine control system according to the hydraulic excavator 1 includes a main controller 5, attitude sensors 34, 35, 36, an antenna 42, an operating device 221, an input display device 222, a construction surface management device 223, and a drive device 241.

[0049] The main controller 5 has a CPU, a RAM, a ROM, an input I / F, and an output I / F connected to each other via a bus. Various devices such as the operating device 221, the input display device 222, and the construction surface management device 223, as well as the attitude sensors 34, 35, 36 and the antenna 42, etc. are connected to the input I / F, and the drive device 241 is connected to the output I / F.

[0050] In such a hardware configuration, the CPU reads a control program (software) stored in a recording medium such as a ROM or an optical disk and expands it onto the RAM, and by executing the expanded control program, the control program and the hardware cooperate to realize the functions of the main controller 5.

[0051] In this embodiment, the main controller 5 is described as a computer configured by a combination of software and hardware. However, it is not limited to this. For example, as an example of the configuration of other computers, an integrated circuit that realizes the functions of the control program executed on the side of the hydraulic excavator 1 may be used.

[0052] The main controller 5 stores or inputs in advance the construction target surface included in the information acquired from the construction surface management device 223. The main controller 5 is a control device that performs control on the drive device 241 based on the control based on the operation signal output from the operation device 221 so that the working device 30 operates along the construction target surface based on the stored or input construction target surface, the positioning information received by the antenna 42, and the attitude of the working device 30 detected by the attitude sensors 34, 35, 36.

[0053] For example, when the main controller 5 receives an operation signal related to the arm 32 from the operating device 221, it outputs a command signal to the electromagnetic control valve corresponding to the boom cylinder 31A in the drive device 241 so that the bucket 33 moves along the target surface of the construction. As a result, the boom 31 rises and falls based on the command from the main controller 5, and excavation work is performed along the target surface of the construction.

[0054] <Functional Configuration of Main Controller 5> Next, the functional configuration of the main controller 5 will be explained with reference to Figure 5.

[0055] Figure 5 is a functional block diagram showing the functions of the main controller 5.

[0056] The main controller 5 includes an information acquisition unit 51, a calculation unit 52, a construction history storage unit 53, a correction target surface generation unit 54, a correction information storage unit 55, a correction target surface distance calculation unit 56, a target speed calculation unit 57, and a command signal output unit 58.

[0057] The information acquisition unit 51 acquires the following data: operation signals output from the operating device 221, data related to the dimensions and mass of the work device 30 output from the input display device 222, information on the target construction surface output from the construction surface management device 223, the current posture (angle) of the boom 31 output from the boom posture sensor 34, the current posture (angle) of the arm 32 output from the arm posture sensor 35, the current posture (angle) of the bucket 33 output from the bucket posture sensor 36, and positioning information of the hydraulic excavator 1 output from the antenna 42.

[0058] The calculation unit 52 includes an attitude calculation unit 52A, a requested operation calculation unit 52B, a construction target surface distance calculation unit 52C, and a positioning error calculation unit 52D.

[0059] The attitude calculation unit 52A calculates the current attitude of the work device 30 based on the current attitudes of the boom 31, arm 32, and bucket 33, respectively, which are acquired by the information acquisition unit 51.

[0060] The requested motion calculation unit 52B calculates the required motion direction for the work device 30 based on the data relating to each dimension and mass of the work device 30 acquired by the information acquisition unit 51 and the current posture of the work device 30 calculated by the posture calculation unit 52A.

[0061] The construction target surface distance calculation unit 52C calculates the relationship between the excavation target position on the construction target surface and the current position of the hydraulic excavator 1, that is, the distance from the current position of the work device 30 (bucket 33) to the excavation target position, based on the information of the construction target surface acquired by the information acquisition unit 51 and the current position of the work device 30 calculated by the position calculation unit 52A.

[0062] The positioning error calculation unit 52D calculates the positioning error of the positioning satellite 41 based on the information of completed construction locations stored in the construction history storage unit 53, the information of the construction target surface acquired by the information acquisition unit 51, and the positioning information of the hydraulic excavator 1 (bucket 33).

[0063] Here, the specific method for calculating the positioning error in the positioning error calculation unit 52D will be explained with reference to Figure 6.

[0064] Figure 6 illustrates an example of a method for calculating positioning error.

[0065] As shown in Figure 6, if there is a known point Z, such as a pile head, at the construction site, the position of the known point Z can be determined using GNSS by aligning the tip of the bucket 33 with the known point Z. Then, by comparing the positioning result of the known point Z during the previous construction with the positioning result of the known point Z during the current construction, the positioning error of the GNSS (positioning satellite 41) with respect to the coordinate system of the construction site (hereinafter referred to as the "site coordinate system") can be calculated.

[0066] For example, let's assume that the GNSS positioning error relative to the site coordinate system at the time of the previous installation is calculated to be, for example, "-32 mm" based on the positioning information of known point Z received by antenna 42 during the previous installation (the positioning result of known point Z by GNSS). Then, let's assume that the GNSS positioning error relative to the current site coordinate system is calculated to be, for example, "+47 mm" based on the positioning information of known point Z currently received by antenna 42.

[0067] In this case, the difference of 79 mm between the previous positioning error of -32 mm and the current positioning error of +47 mm represents the relative GNSS positioning error between the previous and current measurements. This relative GNSS positioning error of 79 mm appears as the difference between the previous construction target surface and the current construction target surface. Therefore, at this construction site, a step S of 79 mm will occur at the boundary between the completed area α and the planned construction area β adjacent to the completed area α.

[0068] Therefore, if there is a known point Z at the construction site, this known point Z becomes the reference position relative to the construction target surface, and the positioning information received by the antenna 42 from the positioning satellite 41 includes information about this reference position (reference position information).

[0069] The positioning error calculation unit 52D then calculates the positioning error in the positioning satellite 41 by comparing the reference position information received by the antenna 42 this time with the reference position information received and stored by the antenna 42 last time.

[0070] Regarding the calculation method for the positioning error in the positioning satellite 41, in addition to a method based on the positioning information of known point Z, there is also a method in which the tip of the bucket 33 is aligned with a specific position within the constructed area α (for example, the position of the tip of the bucket 33 shown on the left side of Figure 3), and the positioning result of the specific position when the constructed area α was constructed is compared with the positioning result of the current specific position.

[0071] In this method, a specific location within the completed construction area α becomes a predetermined location relative to the construction target surface, and the positioning information received by the antenna 42 from the positioning satellite 41 includes information about this predetermined location (predetermined location information). The positioning error calculation unit 52D then calculates the positioning error in the positioning satellite 41 by comparing the predetermined location information related to the specific location received by the antenna 42 this time with the predetermined location information related to the specific location that was previously received and stored by the antenna 42.

[0072] When construction is completed by the machine control of the hydraulic excavator 1, the main controller 5 stores information about the completed area (completed area α) in the construction history storage unit 53.

[0073] The correction target surface generation unit 54 generates a correction target surface Y that corrects the connection state between the completed area α and the construction target surface in history storage unit 53 and the positioning error calculated by the positioning error calculation unit 52D.

[0074] In this embodiment, the correction target surface Y is a sloping connecting surface that extends from the completed construction area α and smoothly continues toward the construction target surface in the planned construction area β.

[0075] Information regarding the length L and gradient θ of the sloping connecting surface that will become the target correction surface Y is stored in the correction information storage unit 55, and the target correction surface generation unit 54 generates the target correction surface Y based on the information regarding the length L or gradient θ of the target correction surface Y stored in the correction information storage unit 55.

[0076] The length L of the correction target surface Y and the gradient θ are both values ​​that the operator can arbitrarily set according to the required smoothness of the construction surface and the allowable construction width at the construction site, and are set in advance via the input display device 222 and stored in the correction information storage unit 55.

[0077] Here, the specific method for generating the correction target surface Y in the correction target surface generation unit 54 will be explained with reference to Figure 7.

[0078] Figure 7 illustrates an example of a method for generating the corrected target surface Y.

[0079] If we let the height of the corrected target surface Y be "H", the height of the construction target surface before correction (the construction target surface in the completed area α; surface X1 shown by the dashed line in Figure 7) be "H0", the distance from the starting point of the corrected target surface be "W", and the positioning error (the difference between the construction target surface based on the positioning information previously received and stored by the antenna 42 and the construction target surface based on the positioning information currently received by the antenna 42) be "H1", then the corrected target surface Y when the length L of the corrected target surface Y is used is expressed by the following equation (1).

[0080] H=cW+H0 (0≦W≦L, c:c=H1 / L)...(1)

[0081] Furthermore, when the gradient (angle) θ of the correction target surface Y is used, the correction target surface Y is expressed by the following equation (2).

[0082] H=W・tanθ+H0 (0≦W≦H1 / tanθ)...(2)

[0083] Thus, since the correction target surface generation unit 54 can be generated using either the length L or the gradient θ of the correction target surface Y, the correction information storage unit 55 only needs to store information regarding the length L of the correction target surface Y and information regarding the gradient θ.

[0084] In Figure 7, the correction target surface Y is shown as a straight plane, but it is not limited to this and may include curved surfaces.

[0085] The correction target surface distance calculation unit 56 calculates the relationship between the position of the correction target surface Y and the current position of the hydraulic excavator 1, that is, the distance from the current position of the work device 30 (bucket 33) to the position of the correction target surface Y, based on the posture of the work device 30 calculated by the posture calculation unit 52A and the correction target surface Y generated by the correction target surface generation unit 54.

[0086] The target speed calculation unit 57 calculates the target operating speed of each cylinder 31A, 32A, 33A (mainly the boom cylinder 31A) based on the current posture of the work device 30 calculated by the posture calculation unit 52A, the required operating direction for the work device 30 calculated by the required operating direction calculation unit 52B, the distance to the excavation target position calculated by the construction target surface distance calculation unit 52C, and the distance to the corrected target surface Y position calculated by the corrected target surface distance calculation unit 56.

[0087] The command signal output unit 58 outputs a command signal to the drive unit 241 according to the target operating speed calculated by the target speed calculation unit 57.

[0088] <Processing executed by the main controller 5> Next, the flow of processing executed within the main controller 5 will be explained with reference to Figure 8.

[0089] Figure 8 is a flowchart showing the processing flow executed by the main controller 5.

[0090] First, when using the machine control function in the hydraulic excavator 1, the main controller 5 stores the GNSS positioning error (corresponding to the previous positioning error) for the field coordinate system calculated based on the positioning information of known point Z in the construction history storage unit 53 (step S501).

[0091] Next, when the command signal output unit 58 outputs a command signal to the drive unit 241 and machine control construction is performed, the main controller 5 stores the machine control construction locations in the construction history storage unit 53 (step S502).

[0092] Then, when construction preparations are initiated by machine control at the same construction site, the information acquisition unit 51 acquires positioning information of known point Z received by the antenna 42 (step S503).

[0093] Next, the main controller 5 calculates the GNSS positioning error (corresponding to the current positioning error) relative to the current site coordinate system based on the positioning information of known point Z acquired in step S503, and stores it in the construction history storage unit 53 (step S504).

[0094] Next, the positioning error calculation unit 52D calculates the relative positioning error between the previous and current positioning errors based on the previous positioning error stored in the construction history storage unit 53 based on the positioning information received by the antenna 42 a predetermined time before in step S501, and the current positioning error stored in the construction history storage unit 53 in step S504 (step S505).

[0095] Next, the correction target surface generation unit 54 generates a slope-shaped correction target surface Y based on the relative positioning error calculated in step S505 and the information about the length or angle (slope) of the correction target surface Y stored in the correction information storage unit 55 (step S506).

[0096] Then, the main controller 5 determines whether the bucket 33 (hydraulic excavator 1) is located within the range of the correction target surface Y adjacent to the completed construction area α (step S507).

[0097] If it is determined in step S507 that the bucket 33 is located within the range of the correction target plane Y (step S507 / YES), the command signal output unit 58 outputs a command signal based on the correction target plane Y generated in step S506 to the drive unit 241 (step S508), and the processing in the main controller 5 ends.

[0098] On the other hand, if it is determined in step S507 that the bucket 33 is not located within the range of the correction target surface Y (step S507 / NO), that is, if the construction of the correction target surface Y is completed, the command signal output unit 58 outputs a command signal based on the construction target surface acquired from the construction surface management device 223 to the drive device 241 (step S509), and the processing in the main controller 5 ends.

[0099] Thus, in construction using the machine control function, even if a step S occurs between adjacent construction target surfaces due to the difference between the GNSS positioning error in the completed area α and the GNSS positioning error in the planned construction area β adjacent to the completed area α, the main controller 5 generates a corrected target surface Y that corrects the connection state of the adjacent construction target surfaces, thereby smoothly connecting the adjacent construction target surfaces. This makes it possible to improve construction quality even in construction using the machine control function.

[0100] Furthermore, in this embodiment, since the correction target surface Y is formed as a sloping connecting surface that extends smoothly from the completed area α toward the planned construction area β, irregularities are less likely to occur between adjacent construction target surfaces, and the construction quality can be further improved.

[0101] Embodiments of the present invention have been described above. It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those having all the described configurations. Furthermore, it is possible to replace some of the configurations of this embodiment with those of other embodiments, and it is also possible to add configurations from other embodiments to the configuration of this embodiment. Moreover, it is possible to add, delete, or replace some of the configurations of this embodiment with those of other embodiments.

[0102] For example, in the above embodiment, a hydraulic excavator 1 was used as an example of a working machine, but it is not limited to this, and any other working machine equipped with a machine control function may be used.

[0103] 1: Hydraulic excavator (working machine) 5: Main controller (control device) 30: Working device 34: Boom attitude sensor (attitude detection device) 35: Arm attitude sensor (attitude detection device) 36: Bucket attitude sensor (attitude detection device) 41: Positioning satellite (positioning device) 42: Antenna (receiving device) 221: Operating device 241: Drive device α: Completed area Y: Correction target surface

Claims

1. A work machine comprising: a main body; a work device attached to the main body; a drive device for driving the work device; an operating device for operating the work device; a receiving device for receiving positioning information output from a positioning device for measuring the position of the main body; a posture detection device for detecting the posture of the work device; and a control device that controls the drive device based on the operation of the operating device so that the work device operates along the construction target surface, based on the construction target surface that is stored or input in advance, the positioning information received by the receiving device, and the posture of the work device detected by the posture detection device, wherein the control device stores a completed area that has been constructed; calculates a positioning error in the positioning device based on the positioning information received by the receiving device and the positioning information received by the receiving device a predetermined time ago; generates a corrected target surface that corrects the connection state between the completed area and the construction target surface adjacent to the completed area, based on the stored completed area and the calculated positioning error. A work machine characterized by outputting a command signal to the drive unit for the work device to operate along the generated correction target surface.

2. The work machine according to claim 1, characterized in that the correction target surface is a connecting surface that extends from the completed area and smoothly continues toward the construction target surface adjacent to the completed area.

3. A work machine according to claim 1, wherein the positioning information includes reference position information for a reference position with respect to the construction target surface, and the control device calculates the positioning error in the positioning device by comparing the reference position information received by the receiving device with the stored reference position information.

4. A work machine according to claim 1, wherein the positioning information includes predetermined position information for a predetermined position on the construction target surface, and the control device calculates the positioning error in the positioning device by comparing the predetermined position information relating to a specific position which is a predetermined position on the construction target surface that has been received by the receiving device and has become the completed area, with the predetermined position information relating to the specific position before it became the completed area and has been stored.

5. A work machine according to claim 1, wherein the control device has information about the length or gradient of the correction target surface stored in advance, and the control device generates the correction target surface based on the stored information about the length or gradient of the correction target surface.

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