Work machine

Abstract

To improve productivity by smoothly transitioning from a state in which a work device is operating independently to an operation that requires a turning operation.SOLUTION: A work machine includes a traveling body, a revolving body, a work device, an attitude detection device that detects the attitudes of the revolving body and the work device, a vessel position detection device that detects a position of a vessel of a loading machine into which material excavated by the work device is loaded, and a control device that performs automatic revolve control to automatically revolve at least the revolving body to a revolve completion angle based on detection results of the attitude detection device and the vessel position detection device. The control device determines whether a revolve start condition for starting the automatic revolve control is satisfied based on the revolving operation state of the revolving body and the operation state of the work device. When the control device determines that the revolve start condition is satisfied, it outputs a revolve operation start command to start revolving the revolving body toward the revolve completion angle regardless of whether the work device is in an operating state.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a work machine. [Background technology]

[0002] There is known a working machine such as a hydraulic excavator that includes a rotating body rotatably attached to a traveling body and an articulated working device attached to the rotating body. The working device attached to the hydraulic excavator includes a boom rotatably attached to the rotating body, an arm rotatably attached to the boom, and a bucket rotatably attached to the arm.

[0003] A hydraulic excavator performs excavation and loading work on excavated materials by performing an excavation operation to excavate soil and other materials, a transport operation to transport the excavated materials to above the bed of the loaded machine such as a dump truck, a discharge operation to discharge the excavated materials onto the bed of the loaded machine, and a return operation to move the working equipment to the excavation position.

[0004] Patent Document 1 discloses a control device and a control method for a work machine (loading machine) that automatically performs a return operation. This Patent Document 1 describes that "the control device for a loading machine is a control device for a loading machine that includes a rotating body that rotates around a rotation center and a working machine having a bucket and attached to the rotating body, and includes a loading target specifying unit that specifies the position and shape of the loading target, an avoidance position specifying unit that specifies an interference avoidance position that is a position a predetermined distance outside the loading target based on the position and shape of the loading target, and a movement processing unit that outputs an operation signal to drive only the rotating body until the bucket reaches the interference avoidance position from the loading position on the loading target, and outputs an operation signal to drive the rotating body and the working machine after the bucket reaches the interference avoidance position, and moves the bucket to an excavation position on the excavation target." [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-41352 A Summary of the Invention [Problem to be solved by the invention]

[0006] Patent Document 1 states that "When the automatic excavation and loading control is continuously executed, the empty rotation start position P01 coincides with the loading position P07," "When the position P of the tip of the arm 132 reaches the loading position P07, the rotation of the rotating body 120 stops," and "When the bucket 133 reaches the loading position P07, the movement processing unit 1112 generates a dump operation signal for rotating the bucket 133 in the dumping direction." In other words, in the technology described in Patent Document 1, the rotating body stops while the bucket is rotated to discharge soil to the loaded machine. Therefore, in order to perform the return operation, it is necessary to output a rotation operation command for rotating the rotating body after the soil discharge is completed.

[0007] However, it takes time for the rotating body to actually start moving after a rotation operation command is output. Therefore, in the technology described in Patent Document 1, there is a risk of productivity (work efficiency) decreasing due to a difference between the timing of completion of the soil release operation and the timing of the actual start of rotation.

[0008] The present invention aims to improve productivity by smoothly transitioning from a state in which the working device is operating alone (e.g., a state in which an excavation operation or a discharge operation is being performed) to an operation that requires a rotation operation (e.g., a transport operation or a return operation). [Means for solving the problem]

[0009] A working machine according to one aspect of the present invention includes a traveling body, a rotating body provided rotatably relative to the traveling body, a working device attached to the rotating body and having a boom, an arm and a bucket, an attitude detection device for detecting an attitude of the rotating body and an attitude of the working device, a vessel position detection device for detecting a position of a vessel of a loading machine into which an excavated material excavated by the working device is loaded, and a control device for performing automatic rotation control for automatically rotating the rotating body at least to a rotation completion angle which is a target rotation angle based on detection results of the attitude detection device and the vessel position detection device. The control device determines whether a rotation start condition for starting the automatic rotation control of the rotating body is satisfied based on a rotation operation state of the rotating body and an operation state of the working device, and when it determines that the rotation start condition is satisfied, outputs a rotation operation start command for starting rotation of the rotating body toward the rotation completion angle at the timing when the rotation start condition is satisfied, regardless of whether the working device is in an operating state or not. Effect of the Invention

[0010] According to the present invention, productivity can be improved by smoothly transitioning from a state in which the working device is operating independently to an operation that requires a swing operation. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a side view of a hydraulic excavator 1 according to the first embodiment. [Diagram 2] FIG. 2 is a diagram showing the hydraulic excavator 1 and a loaded machine 200. As shown in FIG. [Diagram 3] FIG. 3 is a schematic configuration diagram of a hydraulic drive system 50 of the hydraulic excavator 1. [Figure 4] FIG. 4 is a functional block diagram of the control device 40 according to the first embodiment. [Diagram 5] FIG. 5 is a diagram showing the shovel reference coordinate system as viewed from the Y-axis direction. [Figure 6] FIG. 6 is a diagram showing the shovel reference coordinate system as viewed from the Z-axis direction. [Figure 7] FIG. 7 is an explanatory diagram of the excavation operation. [Figure 8] FIG. 8 is an explanatory diagram of the transporting operation and the soil releasing operation. [Figure 9] FIG. 9 is an explanatory diagram of the return operation. [Figure 10] FIG. 10 is a flowchart showing an example of processing by the control device 40 according to the first embodiment, and shows the flow of processing from the start of an excavation operation to the completion of a transport operation. [Figure 11] FIG. 11 is a flowchart showing an example of the processing by the control device 40 according to the first embodiment, and shows the flow of the processing from the start of the soil releasing operation to the completion of the returning operation. [Figure 12] FIG. 12 is a diagram showing the time series changes in the ground angle γ of the bucket 10, the output (ON / OFF) of a rotation operation command, and the rotation angle θsw when an operation transitions from an excavation operation to a transport operation, or from a dumping operation to a return operation, in the first embodiment. [Figure 13] FIG. 13 is a schematic plan view showing a state in which the hydraulic excavator 1 according to the first modification of the first embodiment transitions from the earth releasing operation to the returning operation. [Figure 14] FIG. 14 is a flowchart showing an example of the processing by the control device 40 according to the first modification of the first embodiment, and shows the flow of the processing from the start of the soil releasing operation to the completion of the returning operation. [Figure 15] FIG. 15 is a diagram showing a data table of the third time t3r. [Figure 16] FIG. 16 is a diagram showing the time series changes in the ground angle γ of the bucket 10, the output (ON / OFF) of a swing operation command, and the swing angle θsw when the operation transitions from the soil-discharging operation to the return operation in the first modified example of the first embodiment. [Figure 17] FIG. 17 is a functional block diagram of a control device 240 according to the second embodiment. [Figure 18] FIG. 18 is a flowchart showing an example of processing by the control device 240 according to the second embodiment, and shows the flow of processing from the start of an excavation operation to the completion of a transport operation. [Figure 19]FIG. 19 is a flowchart showing an example of the processing by the control device 240 according to the second embodiment, and shows the flow of the processing from the start of the soil releasing operation to the completion of the returning operation. [Figure 20] FIG. 20 is a diagram showing time series changes in the weight (excavation amount) W of the transported object in the bucket 10, the output (ON / OFF) of a swing operation command, and the swing angle θsw when the operation transitions from excavation operation to transport operation. [Figure 21] FIG. 21 is a diagram showing time series changes in the reduction rate Pd of the transported goods in the bucket 10, the output (ON / OFF) of a swing operation command, and the swing angle θsw when the operation transitions from the earth-discharging operation to the return operation. [Figure 22] FIG. 22 is a diagram showing the relationship between the reduction rate Pd of the transported goods and the ground angle γ of the bucket 10. In FIG. [Figure 23] FIG. 23 is a diagram showing the ground angle conversion tables Tc1 and Tc2 after correction. [Figure 24] FIG. 24 is a functional block diagram of a control device 340 according to the third embodiment. [Diagram 25] FIG. 25 is a flowchart showing an example of processing by the control device 340 according to the third embodiment, and shows the flow of processing from the start of an excavation operation to the completion of a transport operation. [Figure 26] FIG. 26 is a flowchart showing an example of the processing by the control device 340 according to the third embodiment, and shows the flow of the processing from the start of the soil releasing operation to the completion of the returning operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following, an example will be described in which the work machine is a hydraulic excavator. In the following description, when there are a plurality of identical components, a lowercase alphabetical letter may be added to the end of the reference numeral. In addition, the plurality of components may be collectively represented by omitting the lowercase alphabetical letter. For example, when there are two identical traveling hydraulic motors 4a, 4b, these may be collectively represented as traveling hydraulic motor 4.

[0013] First Embodiment Fig. 1 is a side view of a hydraulic excavator 1 according to a first embodiment of the present invention. Fig. 2 is a diagram showing the hydraulic excavator 1 and a loaded machine 200. As shown in Figs. 1 and 2, the hydraulic excavator 1 as a work machine performs an excavation operation for excavating a surface to be excavated, such as the ground, and a loading operation for loading the excavated material, such as earth and sand, into a loaded machine 200, such as a transport vehicle including a dump truck.

[0014] In excavation and loading work, the hydraulic excavator 1 performs an excavation operation in which the bucket 10 is used to excavate an excavation target such as soil and sand, a transport operation in which the rotating body 7 is rotated to transport the excavated material in the bucket 10 to above the loaded machine 200, an earth-discharging operation in which the bucket 10 is operated in the dump direction to discharge the excavated material onto a carrier (tray, vessel) 201 of the loaded machine 200, and a return operation in which the bucket 10 is moved from above the loaded machine 200 to a position for performing the next excavation operation. This excavation and loading cycle is performed multiple times for one loaded machine 200.

[0015] The hydraulic excavator 1 shown in FIG. 1 includes a vehicle body (machine main body) 3 and an articulated working device 2 attached to the vehicle body 3. The vehicle body 3 includes a traveling body 5 and a rotating body 7 provided so as to be rotatable with respect to the traveling body 5. The traveling body 5 travels using a right crawler drive traveling hydraulic motor 4a (see FIG. 3) that drives the right crawler, and a left crawler drive traveling hydraulic motor 4b (see FIG. 3) that drives the left crawler. The rotating body 7 is attached to the upper part of the traveling body 5 via a rotating device, and rotates using a swing hydraulic motor 6 (see FIG. 3) of the swing device. In this embodiment, the traveling hydraulic motor 4a for driving the right crawler and the traveling hydraulic motor 4b for driving the left crawler are collectively referred to as traveling hydraulic motors 4.

[0016] The working device 2 attached to the rotating body 7 has a plurality of driven members (8, 9, 10) rotatably connected and a plurality of hydraulic cylinders (11, 12, 13) for driving the driven members. In this embodiment, a boom 8, an arm 9 and a bucket 10 as three driven members driven by the plurality of hydraulic cylinders (11, 12, 13) are connected in series.

[0017] The boom 8 has a base end portion rotatably connected to the front of the rotating body 7 by a boom pin 8a (see FIG. 5). The arm 9 has a base end portion rotatably connected to the tip of the boom 8 by an arm pin 9a. The bucket 10 is rotatably connected to the tip of the arm 9 by a bucket pin 10a. The boom pin 8a, arm pin 9a, and bucket pin 10a are arranged parallel to one another, and the driven members (8, 9, 10) are capable of relative rotation in the same plane.

[0018] The boom 8 rotates up and down by the telescopic movement of the boom cylinder 11. The arm 9 rotates forward and backward (dump direction and cloud direction) by the telescopic movement of the arm cylinder 12. The bucket 10 rotates forward and backward (dump direction and cloud direction) by the telescopic movement of the bucket cylinder 13. One end of the boom cylinder 11 is connected to the boom 8, and the other end is connected to the frame of the rotating body 7. One end of the arm cylinder 12 is connected to the arm 9, and the other end is connected to the boom 8. One end of the bucket cylinder 13 is connected to the bucket 10 via a bucket link 16, and the other end is connected to the arm 9.

[0019] Fig. 3 is a schematic configuration diagram of a hydraulic drive system 50 of the hydraulic excavator 1. As shown in Fig. 3, the hydraulic drive system 50 includes an engine 103 which is a prime mover mounted on the rotating body 7, and a main pump 102 and a pilot pump 104 which are hydraulic pumps driven by the engine 103. The main pump 102 and the pilot pump 104 are driven by the engine 103 and discharge hydraulic oil.

[0020] The hydraulic drive system 50 includes a flow control valve 101 that controls the flow rate and flow direction of hydraulic oil discharged from a main pump 102, a plurality of solenoid proportional valves 51 that output an operating pressure as an operating signal to the flow control valve 101, a control device 40 that outputs a control signal to the solenoid proportional valve 51, operation devices 20, 21 that are operated by an operator and output a signal according to the operation amount and operation direction to the control device 40, and a control selection switch 24 that outputs a control switching signal to the control device 40 to switch between automatic control and manual control by the operation of the operator. The operation devices 20, 21 and the control selection switch 24 are installed in an operator's cab 71 (see FIG. 1) provided on the revolving body 7.

[0021] The work operation device 20 includes a work operation right lever 22a for operating the boom 8 and the bucket 10, and a work operation left lever 22b for operating the arm 9 and the rotating body 7. In other words, the operation device 20 functions as a boom operation device, a bucket operation device, an arm operation device, and a swing operation device 28. The boom operation device, the bucket operation device, and the arm operation device are also collectively referred to as a work operation device 29. The traveling operation device 21 includes a traveling operation right lever 23a for operating the right crawler, and a traveling operation left lever 23b for operating the left crawler. In this embodiment, the work operation right lever 22a and the work operation left lever 22b are collectively referred to as the operation lever 22, and the traveling operation right lever 23a and the traveling operation left lever 23b are collectively referred to as the operation lever 23.

[0022] The control selection switch 24 is provided on any one of the operation levers 22a, 22b, 23a, 23b. The control selection switch 24 may be configured as a touch sensor of a touch panel provided in the operator's cab 71. The control selection switch 24 is an operation switch for switching between a manual mode in which the operation of the hydraulic excavator 1 is controlled in response to the operation of the operation device 20, and an automatic mode in which the operation of the hydraulic excavator 1 is controlled in response to a target route set by the control device 40. The operator can use the control selection switch 24 to select either the manual mode or the automatic mode at any time.

[0023] The operation system according to this embodiment is an electric lever type operation system in which an electrical signal indicating the amount of operation and the direction of operation is input from the operation device 20 to the control device 40, a control signal is output from the control device 40 to the solenoid proportional valve 51, and an operating pressure is output from the solenoid proportional valve 51 to the flow control valve 101.

[0024] The hydraulic excavator 1 has an operation detection device 56 that detects the operation amount and operation direction of the operation levers 22, 23 and outputs a signal indicating the detection result to the control device 40. The operation detection device 56 has an operation amount sensor 52a that detects the arm operation amount (arm crowding operation amount and arm dumping operation amount) by the work operation left lever 22b, an operation amount sensor 52b that detects the swing operation amount (right swing operation amount and left swing operation amount) by the work operation left lever 22b, an operation amount sensor 52c that detects the boom operation amount (boom raising operation amount and boom lowering operation amount) by the work operation right lever 22a, an operation amount sensor 52d that detects the bucket operation amount (bucket crowding operation amount and bucket dump operation amount) by the work operation right lever 22a, an operation amount sensor 52e that detects the right crawler forward operation amount and right crawler backward operation amount by the travel operation right lever 23a, and an operation amount sensor 52f that detects the left crawler forward operation amount and left crawler backward operation amount by the travel operation left lever 23b. The arm operation amount, boom operation amount, and bucket operation amount are collectively referred to as work operation amount.

[0025] The plurality of operation amount sensors 52 (52a to 52f) are, for example, rotary encoders capable of detecting the amount and direction of operation of the operating levers 22, 23, or potentiometers.

[0026] The control device 40 according to this embodiment controls the turning operation of the working device 2, the traveling operation of the traveling body 5, and the revolving operation of the revolving body 7 according to operation information (amount and direction of operation) of the operating levers 22, 23 by the operator.

[0027] Specifically, the control device 40 outputs a control signal corresponding to the amount and direction of operation of the operating levers 22, 23 by the operator to the solenoid proportional valves 51 (51a to 51l). The solenoid proportional valves 51 are provided in a pilot line 100 to which pressure oil is supplied from a pilot pump 104. The solenoid proportional valves 51 operate when a control signal from the control device 40 is input, and output a secondary pressure generated by reducing the primary pressure of the pilot line 100 as an operating pressure to the flow control valve 101. The flow control valve 101 has a plurality of spool valves provided for each of a plurality of hydraulic actuators (the swing hydraulic motor 6, the arm cylinder 12, the boom cylinder 11, the bucket cylinder 13, the traveling hydraulic motor 4a, and the traveling hydraulic motor 4b). The operating pressure output by the solenoid proportional valves 51 is guided to the pressure receiving chamber of the spool valve, and the spool operates. As a result, the hydraulic oil discharged from the main pump 102 is supplied to the corresponding hydraulic actuator through the spool valve, and the hydraulic actuator is operated.

[0028] The electromagnetic proportional valves 51a and 51b output operation pressure for controlling the pressure oil supplied to the swing hydraulic motor 6 to the pressure receiving chamber of the spool valve of the flow control valve 101 for driving the swing hydraulic motor 6. The electromagnetic proportional valves 51c and 51d output operation pressure for controlling the pressure oil supplied to the arm cylinder 12 to the pressure receiving chamber of the spool valve of the flow control valve 101 for driving the arm cylinder 12. The electromagnetic proportional valves 51e and 51f output operation pressure for controlling the pressure oil supplied to the boom cylinder 11 to the pressure receiving chamber of the spool valve of the flow control valve 101 for driving the boom cylinder 11. The electromagnetic proportional valves 51g and 51h output operation pressure for controlling the pressure oil supplied to the bucket cylinder 13 to the pressure receiving chamber of the spool valve of the flow control valve 101 for driving the bucket cylinder 13. The solenoid proportional valves 51i, 51j output operating pressure for controlling the pressure oil supplied to the traveling hydraulic motor 4a to the pressure receiving chamber of the spool valve of the flow control valve 101 for driving the traveling hydraulic motor 4a. The solenoid proportional valves 51k, 51l output operating pressure for controlling the pressure oil supplied to the traveling hydraulic motor 4b to the pressure receiving chamber of the spool valve of the flow control valve 101 for driving the traveling hydraulic motor 4b.

[0029] The boom cylinder 11, the arm cylinder 12, and the bucket cylinder 13 each extend and retract by the supplied pressure oil, thereby rotating the boom 8, the arm 9, and the bucket 10. This changes the position of the bucket 10 and the attitude of the work implement 2. The swing hydraulic motor 6 rotates by the supplied pressure oil, thereby rotating the swing body 7. The traveling hydraulic motors 4a and 4b rotate by the supplied pressure oil, thereby traveling the traveling body 5. Note that even if the operator does not operate the operation levers 22, 23, the solenoid proportional valves 51a-51l are operated by a control signal from the control device 40, and the flow control valve 101 is operated, thereby enabling the hydraulic actuators (4a, 4b, 6, 11, 12, 13) to be driven.

[0030] The hydraulic excavator 1 is equipped with a posture detection device 53 that detects the posture of the vehicle body 3 (the rotating structure 7) and the posture of the working implement 2 including the ground angle of the bucket 10. The posture detection device 53 is configured to include a boom angle sensor 14, an arm angle sensor 15, a bucket angle sensor 17, a tilt angle sensor 18, and a swing angle sensor 19 as a plurality of posture sensors. The boom angle sensor 14 is attached to the boom pin 8a, detects the rotation angle of the boom 8 relative to the rotating structure 7, and outputs a signal representing the detection result to the control device 40. The arm angle sensor 15 is attached to the arm pin 9a, detects the rotation angle of the arm 9 relative to the boom 8, and outputs a signal representing the detection result to the control device 40. The bucket angle sensor 17 is attached to the bucket link 16, detects the rotation angle of the bucket 10 relative to the arm 9, and outputs a signal representing the detection result to the control device 40. The control device 40 acquires the respective rotation angles of the boom 8, the arm 9, and the bucket 10 by the respective angle sensors 14, 15, 17.

[0031] The method of acquiring the respective rotation angles of the boom 8, the arm 9, and the bucket 10 is not limited to this. The control device 40 may acquire each rotation angle by detecting each angle of the boom 8, the arm 9, and the bucket 10 with respect to a reference plane such as a horizontal plane using an inertial measurement unit (IMU) and converting it into each rotation angle of the boom 8, the arm 9, and the bucket 10. The control device 40 may also acquire each rotation angle by detecting each stroke of the boom cylinder 11, the arm cylinder 12, and the bucket cylinder 13 using a stroke sensor and converting it into each rotation angle of the boom 8, the arm 9, and the bucket 10.

[0032] The inclination angle sensor 18 is attached to the rotating unit 7, detects the inclination angle of the rotating unit 7 (vehicle body 3) with respect to a reference plane such as a horizontal plane, and outputs a signal representing the detection result to the control device 40. The turning angle sensor 19 is attached to a turning device between the running unit 5 and the rotating unit 7, detects the turning angle of the rotating unit 7 with respect to the running unit 5, and outputs a signal representing the detection result to the control device 40.

[0033] Here, the rotation angles of the boom 8, the arm 9, and the bucket 10 are parameters that represent the attitude of the working implement 2. That is, the boom angle sensor 14, the arm angle sensor 15, and the bucket angle sensor 17 function as attitude sensors that detect the attitude of the working implement 2. Also, the inclination angle of the rotating body 7 and the rotation angle of the rotating body 7 relative to the running body 5 are parameters that represent the attitude of the rotating body 7 (vehicle body 3). That is, the inclination angle sensor 18 and the rotation angle sensor 19 function as attitude sensors that detect the attitude of the rotating body 7 (vehicle body 3).

[0034] The hydraulic excavator 1 is equipped with an object detection device 54 that detects objects present within a detection range set around the hydraulic excavator 1. The object detection device 54 also detects the shape, type (excavated material, loading platform 201, etc.) and position of the object. The object detection device 54 is, for example, a LiDAR (Light Detection And Ranging) or a stereo camera, and is attached to the top of the operator's cab 71 (see FIG. 1).

[0035] The object detection device 54 detects, for example, the loading platform 201 of the loading machine 200 onto which the material excavated by the work device 2 is loaded, and detects position information (relative position) of the loading platform 201 with respect to the object detection device 54. In other words, the object detection device 54 has a function as a vessel position detection device that detects the position of the loading platform (vessel) 201. The object detection device 54 also detects the shape of the terrain 210 (see FIG. 2) to be excavated. Note that a plurality of object detection devices 54 may be attached to the hydraulic excavator 1.

[0036] The hydraulic excavator 1 is equipped with a hydraulic oil temperature sensor 55 that detects the temperature of the hydraulic oil discharged from the main pump 102. The hydraulic oil temperature sensor 55 is installed, for example, in a hydraulic oil tank or in a pipe.

[0037] The control device 40 is a computer in which processing devices such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), and a DSP (Digital Signal Processor), internal storage devices such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and an external I / F (Interface) are connected to each other via a bus. An operation detection device 56, a posture detection device 53, an object detection device 54, a control selection switch 24, a hydraulic oil temperature sensor 55, an input device 57, and external storage devices such as a hard disk drive and a large-capacity flash memory are connected to the external I / F of the control device 40.

[0038] The ROM stores programs capable of executing various calculations. In other words, the ROM is a storage medium capable of reading programs that realize the functions of this embodiment. The processing device is a calculation device that expands the programs stored in the ROM into the RAM and executes the programs, and performs predetermined calculations on signals received from the external I / F and storage devices (internal storage device and external storage device) in accordance with the programs.

[0039] The input section of the external I / F converts signals input from various devices (operation detection device 56, attitude detection device 53, object detection device 54, hydraulic oil temperature sensor 55, control selection switch 24, input device 57, etc.) into data that can be calculated by the processing device. The output section of the external I / F generates an output signal according to the calculation result by the processing device, and outputs the signal to various devices (electromagnetic proportional valve 51, etc.).

[0040] The attitude detection device 53 includes attitude sensors (14, 15, 17) that detect the attitude of the above-mentioned working device 2, and attitude sensors (18, 19) that detect the attitude of the revolving body 7 (vehicle body 3).

[0041] When the manual mode is set, the control device 40 controls the operations of the revolving structure 7 and the work implement 2 based on operation information detected by the operation detection device 56. When the automatic mode is set, the control device 40 controls the operations of the revolving structure 7 and the work implement 2 based on the attitudes of the revolving structure 7 and the work implement 2 and the position information of the platform 201.

[0042] When the excavation operation and the soil releasing operation are performed automatically, the control device 40 automatically operates the working device 2 from the operation start posture to the operation completion posture based on the detection results of the posture detection device 53 and the object detection device 54. Furthermore, when the transport operation and the return operation are performed automatically, the control device 40 automatically rotates the rotating body 7 from the rotation start angle to the rotation completion angle (executes automatic rotation control) based on the detection results of the posture detection device 53 and the object detection device 54, and automatically operates the working device 2 from the operation start posture to the operation completion posture.

[0043] Fig. 4 is a functional block diagram of the control device 40. As shown in Fig. 4, the control device 40 executes a program stored in the ROM to function as an attitude calculation unit 41, an object position calculation unit 42, a motion transition determination unit 49, a turning start determination unit 43, an excavation control unit 44, a transportation control unit 45, a release control unit 46, a return control unit 47, and an actuator command unit 48.

[0044] The ROM of the control device 40 stores in advance an excavator reference coordinate system used to specify the position and posture of the components of the hydraulic excavator 1, the dimensions of the components of the hydraulic excavator 1, data on the mounting position of the object detection device 54, and the like. The excavator reference coordinate system of this embodiment is defined as a right-handed coordinate system with the origin O being the point where the central axis of rotation intersects with the ground G, as shown in Figs. 5 and 6. In the excavator reference coordinate system of this embodiment, the forward direction of the traveling body 5 is defined as the positive direction of the X-axis. In the excavator reference coordinate system of this embodiment, the direction extending upward from the origin O parallel to the central axis of rotation is defined as the positive direction of the Z-axis. In the excavator reference coordinate system of this embodiment, the direction perpendicular to each of the X-axis and Z-axis is defined as the positive direction of the Y-axis, and the left side of the traveling body 5. In this way, the excavator reference coordinate system of this embodiment is a coordinate system set based on the traveling body 5, and the XY plane is fixed to the ground (traveling surface) G on which the traveling body 5 contacts.

[0045] In the excavator reference coordinate system of this embodiment, the rotation angle θsw of the rotating body 7 is 0 degrees when the hydraulic excavator 1 is in the reference posture, i.e., when the working implement 2 is parallel to the X-axis. When the rotation angle θsw of the rotating body 7 is 0 degrees, the motion plane of the working implement 2 is parallel to the XZ plane, the lifting motion direction of the boom 8 is the positive direction of the Z-axis, and the dumping direction of the arm 9 and bucket 10 is the positive direction of the X-axis.

[0046] The posture calculation unit 41 calculates the posture of the components of the hydraulic excavator 1 in the excavator reference coordinate system from the detection signal of the posture detection device 53. Specifically, the posture calculation unit 41 calculates the rotation angle (hereinafter also referred to as boom angle) θbm of the boom 8 with respect to the X-axis from the detection signal of the rotation angle of the boom 8 output from the boom angle sensor 14. The posture calculation unit 41 calculates the rotation angle (hereinafter also referred to as arm angle) θam of the arm 9 with respect to the boom 8 from the detection signal of the rotation angle of the arm 9 output from the arm angle sensor 15. The posture calculation unit 41 calculates the rotation angle (hereinafter also referred to as bucket angle) θbk of the bucket 10 with respect to the arm 9 from the detection signal of the rotation angle of the bucket 10 output from the bucket angle sensor 17. The posture calculation unit 41 calculates the swing angle θsw of the swing body 7 with respect to the X-axis (traveling body 5) from the detection signal of the swing angle of the swing body 7 output from the swing angle sensor 19.

[0047] The posture calculation unit 41 calculates the positions of the boom 8, the arm 9, and the bucket 10 in the shovel reference coordinate system, that is, the planar positions specified by the X-coordinate and the Y-coordinate, and the heights from the ground G specified by the Z-coordinate, based on the calculated rotation angles θbm, θam, θbk of the working device 2 and the rotation angle θsw of the rotating body 7, and the boom length Lbm, the arm length Lam, and the bucket length Lbk. The boom length Lbm is the length from the boom pin 8a to the arm pin 9a. The arm length Lam is the length from the arm pin 9a to the bucket pin 10a. The bucket length Lbk is the length from the bucket pin 10a to the tip (tip) of the bucket 10. The boom pin 8a is provided at a position offset by Lox in the X-axis direction from the rotation center axis (Z-axis) when the rotation angle is set to 0 degrees.

[0048] Although not shown, the attitude calculation unit 41 calculates the inclination angle (pitch angle and roll angle) of the vehicle body 3 (traveling body 5) with respect to a reference plane from the detection signal of the inclination angle of the vehicle body 3 output from the inclination angle sensor 18. The reference plane is, for example, a horizontal plane perpendicular to the direction of gravity. The attitude calculation unit 41 calculates a ground angle γ, which is the angle of the bucket 10 with respect to a horizontal plane (ground G) perpendicular to the direction of gravity, from the inclination angle of the vehicle body 3 and each of the rotation angles θbm, θam, and θbk of the working device 2. The ground angle γ of the bucket 10 is an angle that a straight line SL passing through the tip of the bucket 10 and the bucket pin 10a forms with respect to the horizontal plane (ground G). The ground angle γ of the bucket 10 is 0 (zero) degrees when the opening of the bucket 10 faces upward and the straight line SL is parallel to the horizontal plane (ground G), and increases as the bucket dump operation progresses. The ground angle γ of the bucket 10 is 180 degrees when the opening of the bucket 10 faces downward and the straight line SL is parallel to the horizontal plane (ground surface G).

[0049] The object position calculation unit 42 shown in Fig. 4 calculates the position of the platform 201 of the loaded machine 200 in the shovel reference coordinate system (the planar position specified by the X coordinate and the Y coordinate, and the height from the ground G specified by the Z coordinate) based on the position information of the platform 201 detected by the object detection device 54, the rotation angle θsw of the rotating body 7 calculated by the attitude calculation unit 41, and the mounting position of the object detection device 54 in the shovel reference coordinate system. The position information of the platform 201 is information on the relative position of the platform 201 of the loaded machine 200 with respect to the object detection device 54. In this way, the control device 40 according to this embodiment acquires the relative position of the platform 201 with respect to the hydraulic excavator 1 (X, Y, Z coordinates in the shovel reference coordinate system) using the object detection device 54.

[0050] The position information of the platform 201 acquired by the control device 40 is, for example, the position coordinates of the four corners of the upper surface of the platform 201 which is rectangular in plan view, i.e., the position coordinates of the front and rear ends of the upper edge of the left side (left end) and the front and rear ends of the upper edge of the right side (right end) of the platform 201. In other words, it can be said that the position information of the platform 201 acquired by the control device 40 includes information on the relative position and relative angle of the platform 201 with respect to the revolving body 7. In other words, in this embodiment, the control device 40 uses the object detection device 54 to acquire various pieces of information related to the relative position of the platform 201 of the loaded machine 200, on which the excavated material excavated by the working device 2 is loaded, with respect to the working device 2, as relative position information.

[0051] Similarly to calculating the position information of the loading platform 201, the object position calculation unit 42 also calculates the position information of characteristic points (for example, the abscissa, the toe, etc.) of the shape of the terrain 210 to be excavated.

[0052] The excavation control unit 44, the transportation control unit 45, the soil discharge control unit 46, and the return control unit 47 calculate a target route for automatically performing excavation work, transportation work, soil discharge work, and return work by the hydraulic excavator 1, and a target speed of each hydraulic actuator on the target route. The excavation control unit 44 calculates a target route for excavating earth and sand using the bucket 10, and a target speed of each hydraulic actuator on the target route. The transportation control unit 45 calculates a target route for moving the bucket 10 storing the excavated material (transported material) onto the platform 201 of the loaded machine 200, and a target speed of each hydraulic actuator on the target route. The soil discharge control unit 46 calculates a target route for discharging the excavated material held in the bucket 10 onto the platform 201 of the loaded machine 200, and a target speed of each hydraulic actuator on the target route. The return control unit 47 calculates a target route for moving the bucket 10 from the platform 201 of the loaded machine 200 to the next excavation start position, and a target speed of each hydraulic actuator on the target route. Note that the target speed on the target route can also be said to be a target speed for each calculation cycle (control cycle).

[0053] Although the excavation control unit 44, the transportation control unit 45, the soil discharge control unit 46, and the return control unit 47 perform various calculations in different work situations, they have similar functions, and therefore, hereinafter, they are also collectively referred to as the operation control unit 400. The operation control unit 400 generates a target path for a control point (e.g., the tip of the bucket 10) of the work implement 2. The operation control unit 400 also calculates a target value γt of the ground angle of the bucket 10 on the target path. The operation control unit 400 causes the tip of the bucket 10 to follow the target path, and calculates target speeds of each hydraulic actuator for causing the actual ground angle γ of the bucket 10 to follow the target value γt.

[0054] The excavation operation, the transport operation, the soil dumping operation, and the return operation during automatic operation will be described with reference to Figs. 7 to 9. Fig. 7 is an explanatory diagram of the excavation operation. As shown in Fig. 7, the excavation control unit 44 generates an excavation start position DP1, an excavation completion position DP2, and a target path DPT for the excavation operation which is a path connecting the excavation start position DP1 and the excavation completion position DP2. The excavation control unit 44 also sets a target value γt of the ground angle of the bucket 10 on the target path DPT. In this way, the excavation control unit 44 sets target values ​​for both the position and the angle of the bucket 10 in order to move a control point such as the tip of the bucket 10 along the target path DPT.

[0055] FIG. 8 is an explanatory diagram of the transport operation and the soil releasing operation. As shown in FIG. 8, the transport control unit 45 generates a transport start position CP1, a transport completion position CP2, and a target path CPT of the transport operation which is a path connecting the transport start position CP1 and the transport completion position CP2. The transport start position CP1 and the transport completion position CP2 can be defined by a turning angle θsw and the attitude of the working device 2. The turning angle θsw at the transport start position CP1 is an angle at which turning for the transport operation starts, and is hereinafter also referred to as a turning start angle of the transport operation. In addition, the turning angle θsw at the transport completion position CP2 is an angle at which turning for the transport operation is completed, and is hereinafter also referred to as a turning completion angle of the transport operation. In addition, the soil releasing control unit 46 generates a soil releasing start position LP1, a soil releasing completion position LP2, and a target path LPT of the soil releasing operation which is a path connecting the soil releasing start position LP1 and the soil releasing completion position LP2.

[0056] 9, the return control unit 47 generates a return start position RP1, a return completion position RP2, and a target path RPT of the return motion which is a path connecting the return start position RP1 and the return completion position RP2. The return start position RP1 and the return completion position RP2 can be determined by a rotation angle θsw and the attitude of the working device 2. The rotation angle θsw at the return start position RP1 is the angle at which rotation for the return motion starts, and will hereinafter also be referred to as the rotation start angle of the return motion. Moreover, the rotation angle θsw at the return completion position RP2 is the angle at which rotation for the return motion is completed, and will hereinafter also be referred to as the rotation completion angle of the return motion.

[0057] The transportation control unit 45, the soil discharge control unit 46, and the return control unit 47, like the excavation control unit 44, set target values ​​for both the position and angle of the bucket 10 to move the tip of the bucket 10 along the target paths CPT, LPT, RPT.

[0058] Each operation control unit 400 shown in FIG. 4 (excavation control unit 44, transportation control unit 45, soil release control unit 46, and return control unit 47) calculates a target speed for each hydraulic actuator based on the target values ​​of the position and angle of the bucket 10.

[0059] The motion transition determination unit 49 determines whether or not each motion transition condition from the excavation motion to the transport motion, from the transport motion to the dumping motion, from the dumping motion to the return motion, and from the return motion to the excavation motion is satisfied. When the motion transition condition is satisfied, the motion transition determination unit 49 generates a start command for starting the next motion. The motion transition condition is satisfied when the tip of the bucket 10 has reached the completion position of the target path, and is not satisfied when the tip of the bucket 10 has not reached the completion position of the target path.

[0060] For example, when an excavation operation is being performed and the bucket 10 reaches the excavation completion position DP2, which is the end of the target path DPT of the excavation operation, the operation transition judgment unit 49 determines that the operation transition condition from the excavation operation to the transporting operation has been met, and outputs a command to start the transporting operation to the transport control unit 45.

[0061] Moreover, the operation transition determination unit 49 sets the control mode to either the automatic mode or the manual mode based on an operation command from the control selection switch 24 .

[0062] When the manual mode is set, the actuator command unit 48 calculates a target speed corresponding to the amount of operation of the operating lever 22 detected by the operation detection device 56. Furthermore, the actuator command unit 48 calculates a control current value to the solenoid proportional valve 51 according to the calculated target speed, and outputs a control current corresponding to the calculation result to the solenoid proportional valve 51. In other words, the actuator command unit 48 outputs a control signal to the solenoid proportional valve 51 so that the boom cylinder 11, the arm cylinder 12, the bucket cylinder 13, and the swing hydraulic motor 6 operate at the target speed corresponding to the amount of operation detected by the operation detection device 56.

[0063] When the automatic mode is set, the actuator command unit 48 calculates a control current value to the electromagnetic proportional valve 51 according to the target speed calculated by the operation control unit 400, and outputs a control current according to the calculation result to the electromagnetic proportional valve 51. In other words, the actuator command unit 48 outputs a control signal (operation command) to the electromagnetic proportional valve 51 so that the boom cylinder 11, the arm cylinder 12, the bucket cylinder 13, and the swing hydraulic motor 6 operate at the target speed calculated by the operation control unit 400. Note that the control signal output from the actuator command unit 48 to the electromagnetic proportional valves 51a, 51b in order to operate the swing hydraulic motor 6 is referred to as a "swing operation command", and in particular, a swing operation command that starts the swing of the swing body 7 when the swing operation of the swing body 7 is stopped is referred to as a "swing operation start command".

[0064] Generally, it takes about 0.1 to 1 second from when a swing operation start command is output until hydraulic oil is supplied to the swing hydraulic motor 6 and the swing body 7 actually starts moving. Therefore, in this embodiment, in a state in which an excavation operation is being performed, the control device 40 outputs a swing operation start command for the transport operation before the operation transition condition from the excavation operation to the transport operation is satisfied, so that the swing body 7 is rotated immediately after the excavation operation is completed. Similarly, in a state in which an earth-discharging operation is being performed, the control device 40 outputs a swing operation start command for the return operation before the operation transition condition from the earth-discharging operation to the return operation is satisfied, so that the swing body 7 is rotated immediately after the earth-discharging operation is completed.

[0065] The swing start determination unit 43 determines whether or not to output a swing operation start command for executing an operation requiring swing (transport operation and return operation) without waiting for the completion of the preceding work (digging operation and soil dumping operation). In other words, the swing start determination unit 43 has a function of determining the timing to output a swing operation start command.

[0066] When the ground angle γ of the bucket 10 reaches the excavation operation completion angle γ1c and the tip of the bucket 10 reaches the excavation completion position DP2, the excavation operation by the working device 2 is completed. The excavation operation completion angle γ1c is the completion angle of the operation of the working device 2 excavating the excavation target. The posture of the working device 2 when the ground angle γ of the bucket 10 reaches the excavation operation completion angle γ1c is referred to as the excavation operation completion posture. When the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r and the tip of the bucket 10 reaches the earth-discharging completion position LP2, the earth-discharging operation by the working device 2 is completed. The earth-discharging operation completion angle γ1r is the completion angle of the operation of the working device 2 discharging the excavated material in the bucket 10 above the loading platform 201. The posture of the working device 2 when the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r is referred to as the earth-discharging operation completion posture. Hereinafter, the excavation operation completion posture and the soil-discharging operation completion posture are also collectively referred to as the operation completion posture. Also, the excavation operation completion angle γ1c and the soil-discharging operation completion angle γ1r are also collectively referred to as the operation completion angle γ1.

[0067] The rotation start determination unit 43 determines whether or not a rotation start condition for starting automatic rotation control of the rotating body 7 is satisfied when the rotation operation of the rotating body 7 has stopped and the work implement 2 is operating. The rotation start condition is satisfied when it is predicted that the rotation of the rotating body 7 will start after the ground angle γ of the bucket 10 reaches the operation completion angle γ1 if a rotation operation start command is output at the current time.

[0068] The rotation start condition is met when the working device 2 reaches a predetermined posture before the operation completion posture while moving toward the operation completion posture. Here, the predetermined posture is a posture at which, if a rotation operation start command is output when the working device 2 is in that posture, the rotation of the rotating body 7 actually starts immediately after the working device 2 reaches the operation completion posture.

[0069] Specifically, as described below, the determination as to whether the swing start condition is satisfied is performed by calculating a first time t1 and a second time t2 and comparing the calculated first time t1 and second time t2. The swing start determination unit 43 calculates the first time t1 from when a swing operation start command is output to when the operation of the swing body 7 actually starts. Hereinafter, the first time t1 when an excavation operation is being performed is referred to as a first time t1c, and the first time t1 when an earth-discharging operation is being performed is referred to as a first time t1r.

[0070] The first time t1 may be obtained by performing a calculation using a mathematical model of the hydraulic excavator 1, or by experimentally measuring the time from when a swing operation start command is given to the hydraulic excavator 1 until it starts moving and saving the value. The mathematical model of the hydraulic excavator 1 is represented, for example, by an equation of motion of a four-link system that operates by a driving torque, with the swing body 7 and the three driven members (boom 8, arm 9, and bucket 10) constituting the work device 2 being rigid bodies. The driving torque used in the equation of motion can be converted from the pressure acting on each hydraulic actuator. Furthermore, a transfer function for a speed command to each hydraulic actuator may be adopted as the mathematical model of the hydraulic excavator 1.

[0071] Here, the first time t1 becomes longer as the moment of inertia of the working device 2 increases. For this reason, it is preferable to determine the first time t1 taking into consideration the attitude of the working device 2. In addition, the first time t1 also changes depending on the temperature of the hydraulic oil (i.e., the viscosity of the hydraulic oil). For this reason, it is preferable to determine the first time t1 taking into consideration the temperature of the hydraulic oil.

[0072] For example, the swing start determination unit 43 calculates the first time t1 using characteristic data of the first time t1 according to the posture of the working device 2 (boom angle, arm angle, bucket angle) and the temperature of the hydraulic oil. The characteristic data of the first time t1 may be a data table of the first time t1 that changes according to the posture of the working device 2 and the temperature of the hydraulic oil, or may be function data. Note that the characteristic data of the first time t1c and the characteristic data of the first time t1r may be the same or different. The swing start determination unit 43 refers to the characteristic data of the first time t1 and calculates the first time t1 based on the posture of the working device 2 calculated by the posture calculation unit 41 and the temperature of the hydraulic oil detected by the hydraulic oil temperature sensor 55.

[0073] The swing start determination unit 43 calculates a second time t2 from the current time until the working implement 2 reaches the operation completion posture. The second time t2 can also be said to be the time from the current time until the ground angle γ of the bucket 10 reaches the operation completion angle γ1. Hereinafter, the second time t2 when an excavation operation is being performed is referred to as a second time t2c, and the second time t2 when an earth-discharging operation is being performed is referred to as a second time t2r.

[0074] The second time t2c corresponds to a predicted time from the current time until the tip of the bucket 10 reaches the excavation completion position DP2. The second time t2r corresponds to a predicted time from the current time until the tip of the bucket 10 reaches the soil discharge completion position LP2.

[0075] The swing start determination unit 43 calculates the second time t2c based on the current attitude of the work implement 2 calculated by the attitude calculation unit 41, the target route DPT calculated by the excavation control unit 44, and the target speed of each hydraulic actuator up to the excavation operation completion attitude. Similarly, the swing start determination unit 43 calculates the second time t2r based on the current attitude of the work implement 2 calculated by the attitude calculation unit 41, the target route LPT calculated by the soil release control unit 46, and the target speed of each hydraulic actuator up to the soil release operation completion attitude.

[0076] The second time t2 is not limited to being calculated by the turning start determination unit 43. The excavation control unit 44 or the soil discharge control unit 46 may calculate the second time t2 and output the calculated second time t2 to the turning start determination unit 43.

[0077] When the second time t2 becomes shorter than the first time t1, i.e., when the second time t2 transitions from a state in which it is longer than the first time t1 to a state in which it is shorter than the first time t1, the turn start judgment unit 43 judges that the turn start condition is met and sets a turn flag indicating the judgment result to on.

[0078] When an excavation operation is being performed, the rotation start determination unit 43 determines that the rotating body 7 will start rotating immediately after the control point of the bucket 10 reaches the excavation completion position DP2, and turns on the transport rotation flag. When an earth-discharging operation is being performed, the rotation start determination unit 43 determines that the rotating body 7 will start rotating immediately after the control point of the bucket 10 reaches the earth-discharging completion position LP2, and turns on the return rotation flag.

[0079] In this way, the swing start determination unit 43 determines that the swing start condition is satisfied when the second time t2 becomes shorter than the first time t1 due to the operation of the working implement 2, such as an excavation operation or a soil dumping operation. In other words, the swing start determination unit 43 determines whether or not the swing start condition is satisfied based on the operating state of the working implement 2. In addition, the swing start condition is premised on the fact that the swing operation has stopped. For this reason, the swing start determination unit 43 determines whether or not the swing start condition is satisfied based on not only the operating state of the working implement 2 but also the swing operation state of the rotating body 7.

[0080] When the transport swing flag is set to ON during an excavation operation, the transport control unit 45 starts automatic swing control of the swing body 7 in the transport operation while continuing the excavation operation. As a result, a swing operation start command for starting the operation of the swing body 7 in the direction from the transport start position CP1 toward the transport completion position CP2 is output from the actuator command unit 48 to the solenoid proportional valve 51. When the return swing flag is set to ON during an earth-discharging operation, the return control unit 47 starts automatic swing control of the swing body 7 in the return operation while continuing the earth-discharging operation. As a result, a swing operation start command for starting the operation of the swing body 7 in the direction from the return start position RP1 toward the return completion position RP2 is output from the actuator command unit 48 to the solenoid proportional valve 51.

[0081] An example of the flow of processing executed by the control device 40 according to the first embodiment will be described with reference to Figs. 10 and 11. Fig. 10 is a flowchart showing an example of processing by the control device 40 according to the first embodiment, showing the flow of processing from the start of the excavation operation to the completion of the transport operation. Fig. 11 is a flowchart showing an example of processing by the control device 40 according to the first embodiment, showing the flow of processing from the start of the soil releasing operation to the completion of the return operation. In the processing shown in the flowcharts of Figs. 10 and 11, a case will be described in which only one operation is executed each of the excavation operation, transport operation, soil releasing operation, and return operation. However, this series of operations may be executed multiple times. In addition, it is not necessarily necessary to start with the excavation operation.

[0082] 10, in step S101, when an operation is performed with control selection switch 24 to change the control mode to the automatic mode, operation transition determination unit 49 sets the control mode to the automatic mode. When the automatic mode is set, actuator command unit 48 starts an excavation operation by the work implement 2 based on the target speed of each hydraulic actuator calculated by excavation control unit 44. In other words, excavation control by excavation control unit 44 is started. In the excavation control, excavation control unit 44 automatically operates the work implement 2 until the ground angle γ of the bucket 10 becomes an excavation operation completion angle γ1c.

[0083] In the next step S102, the swing start determination unit 43 calculates a time (first time) t1c from when the swing body 7 starts moving after the swing operation start command of the transport operation is output to when the swing body 7 starts moving. In the next step S103, the swing start determination unit 43 calculates a time (second time) t2c from the current time to when the bucket 10 reaches the excavation completion position DP2.

[0084] In the next step S104, the swing start determination unit 43 compares the first time t1c with the second time t2c. Through this comparison, the swing start determination unit 43 determines whether or not the movement of the swing body 7 in the predetermined direction will start after the work implement 2 reaches the excavation operation completion posture when a swing operation start command is output at the current time. That is, the process of step S104 is a process for determining whether or not the swing start condition is satisfied.

[0085] If the first time t1c is equal to or less than the second time t2c, the turning start determination unit 43 determines that the turning start condition is not satisfied and returns the process to step S103. If the first time t1c is greater than the second time t2c, the turning start determination unit 43 determines that the turning start condition is satisfied, sets the transportation turning flag to ON, and proceeds to step S105.

[0086] In step S105, the transport control unit 45 starts controlling the revolving body 7 in the transport operation. That is, in step S105, the transport control unit 45 outputs a rotation operation start command for the transport operation. In the next step S106, the operation transition determination unit 49 determines whether or not the operation transition condition from the excavation operation to the transport operation is satisfied. When the ground angle γ of the bucket 10 reaches the excavation operation completion angle γ1c and the tip of the bucket 10 reaches the excavation completion position DP2, the operation transition determination unit 49 determines that the operation transition condition from the excavation operation to the transport operation is satisfied, and proceeds to step S107. When the ground angle γ of the bucket 10 has not reached the excavation operation completion angle γ1c or when the tip of the bucket 10 has not reached the excavation completion position DP2, the operation transition determination unit 49 determines that the operation transition condition from the excavation operation to the transport operation is not satisfied. The process of step S106 is repeatedly executed at a predetermined calculation period until a positive determination is made.

[0087] In step S107, the transportation control unit 45 starts control of the working device 2 in the transportation operation. As described above, the control of the revolving body 7 in the transportation operation is started before the operation transition condition is established (step S105).

[0088] In the next step S108, when the operation transition condition from the transport operation to the dumping operation is satisfied, the transport operation is completed. When the transport operation is completed, the transport control unit 45 sets the transport rotation flag to OFF. When the transport operation is completed, the process proceeds to step S109 shown in FIG. 11, and the operation transition determination unit 49 transitions the operation to the dumping operation. This starts the dumping control by the dumping control unit 46. In the dumping control, the dumping control unit 46 automatically operates the work device 2 until the ground angle γ of the bucket 10 becomes the dumping operation completion angle γ1r.

[0089] In the next step S110, the swing start determination unit 43 calculates a time (first time) t1r from the swing command for the return operation until the swing body 7 starts moving. In the next step S112, the swing start determination unit 43 calculates a time (second time) t2r from the current time until the bucket 10 reaches the release completion position LP2.

[0090] In the next step S113, the swing start determination unit 43 compares the first time t1r with the second time t2r. Through this comparison, the swing start determination unit 43 determines whether or not the operation of the swing body 7 in the predetermined direction will start after the work implement 2 reaches the soil-discharging operation completion posture when a swing operation start command is output at the current time. That is, the process of step S113 is a process for determining whether or not the swing start condition is satisfied.

[0091] If the first time t1r is equal to or less than the second time t2r, the turn start determination unit 43 determines that the turn start condition is not satisfied and returns the process to step S112. If the first time t1r is greater than the second time t2r, the turn start determination unit 43 determines that the turn start condition is satisfied, sets the return turn flag to ON, and proceeds to step S114.

[0092] In step S114, the return control unit 47 starts controlling the revolving body 7 in the return operation. That is, in step S114, the return control unit 47 outputs a swing operation start command for the return operation. In the next step S115, the operation transition determination unit 49 determines whether or not the operation transition condition from the dumping operation to the return operation is satisfied. When the ground angle γ of the bucket 10 reaches the dumping operation completion angle γ1r and the tip of the bucket 10 reaches the dumping completion position LP2, the operation transition determination unit 49 determines that the operation transition condition from the dumping operation to the return operation is satisfied, and proceeds to step S116. When the ground angle γ of the bucket 10 has not reached the dumping operation completion angle γ1r or when the tip of the bucket 10 has not reached the dumping completion position LP2, the operation transition determination unit 49 determines that the operation transition condition from the dumping operation to the return operation is not satisfied. The process of step S115 is repeatedly executed at a predetermined calculation period until a positive determination is made.

[0093] In step S116, the return control unit 47 starts control of the working implement 2 in the return motion. As described above, the control of the revolving body 7 in the return motion is started before the motion transition condition is satisfied (step S114).

[0094] In the next step S108, when the tip of the bucket 10 reaches the return completion position RP2, the return operation is completed. When the return operation is completed, the return control unit 47 sets the return swing flag to OFF. When the return operation is completed, the process shown in the flowchart in FIG. 11 ends.

[0095] Hereinafter, main operations of the hydraulic excavator 1 according to this embodiment will be described with reference to Figs. 7 to 9 and 12. Fig. 12 is a diagram showing time series changes in the ground angle γ of the bucket 10, the presence or absence (ON / OFF) of a swing operation command, and the swing angle θsw when an operation transitions from an excavation operation to a transport operation, or from an earth dumping operation to a return operation. The horizontal axis in Figs. 12(a) to 12(c) indicates time. The vertical axis in Fig. 12(a) indicates the ground angle γ of the bucket 10, the vertical axis in Fig. 12(b) indicates the presence or absence of an output of a swing operation command, and the vertical axis in Fig. 12(c) indicates the swing angle θsw. Note that the swing angle θsw is shown as a graph that increases in the positive direction from the reference position to the operation completion angle, with the position at which the excavation operation or the earth dumping operation is started as a reference position. Also, in Fig. 12, for convenience of explanation, the time series changes in each parameter of the transition from the excavation operation to the transport operation and the transition from the earth dumping operation to the return operation are shown in a common graph. However, the time series changes of the parameters during the transition from the excavation operation to the transport operation and during the transition from the dumping operation to the return operation are actually different.

[0096] First, the operation when transitioning from an excavation operation to a transport operation will be described with reference to Fig. 7 and Fig. 12. The control device 40 judges whether or not a rotation start condition is satisfied when the rotation operation of the rotating body 7 is stopped and the working implement 2 is automatically operating so that the ground angle γ of the bucket 10 approaches the excavation operation completion angle γ1c (steps S101 to S104 in Fig. 10).

[0097] When the rotation start condition is satisfied at time T2 after a certain time has elapsed from state S10 when the excavation operation is started (Yes in step S104 in FIG. 10), the automatic rotation control of the rotating body 7 is started (state S11). On the other hand, at time T1 before time T2, the rotation start condition is not satisfied (No in step S104 in FIG. 10), so the automatic rotation control of the rotating body 7 is not started. The automatic rotation control of the rotating body 7 is started (a rotation operation start command is output) at a stage (time T2) before time T3 when the excavation operation is completed. In this way, the control device 40 outputs a rotation operation start command to start rotating the rotating body 6 toward the rotation completion angle at the timing (time T2) when the rotation start condition is satisfied. As a result, the rotating body 7 actually starts to rotate (state S12) immediately after the ground angle γ of the bucket 10 reaches the operation completion angle γ1 (excavation operation completion angle γ1c). That is, the timing when the ground angle γ of the bucket 10 reaches the excavation operation completion angle γ1c and the timing when the rotating body 7 starts to rotate are approximately the same. This allows a smooth transition from the excavation operation to the transport operation.

[0098] The excavation control unit 44 sets a position where there is no earth and sand around the bucket 10 as the excavation completion position DP2 based on the information on the excavation target topography 61 acquired by the object detection device 54. Therefore, even if the turning operation is started immediately after the excavation completion position DP2 is reached, there is no earth and sand that will strike the bucket 10 sideways, so damage to the work implement 2 can be prevented.

[0099] At time T3, when the ground angle γ of the bucket 10 reaches the excavation operation completion angle γ1c, transport control of the work implement 2 is started. When the rotating body 7 and the work implement 2 perform the transport operation and the tip of the bucket 10 reaches the transport completion position CP2 (see FIG. 8), the transport operation is completed.

[0100] Next, the operation when transitioning from the dumping operation to the return operation will be described with reference to Figures 9 and 12. The control device 40 judges whether or not the swing start condition is satisfied when the swing operation of the swing body 7 is stopped and the work implement 2 is automatically operating so that the ground angle γ of the bucket 10 approaches the dumping operation completion angle γ1r (steps S109 to S113 in Figure 11).

[0101] When the rotation start condition is satisfied at time T2 when a certain time has elapsed from the state S20 when the soil dumping operation is started (Yes in step S113 in FIG. 11), the automatic rotation control of the rotating body 7 is started. On the other hand, at time T1 before time T2, the rotation start condition is not satisfied (No in step S113 in FIG. 11), so the automatic rotation control of the rotating body 7 is not started. The automatic rotation control of the rotating body 7 is started (a rotation operation start command is output) at a stage (time T2) before time T3 when the soil dumping operation is completed. In this way, the control device 40 outputs a rotation operation start command to start rotating the rotating body 6 toward the rotation completion angle at the timing (time T2) when the rotation start condition is satisfied. As a result, the rotating body 7 actually starts to rotate immediately after the ground angle γ of the bucket 10 reaches the operation completion angle γ1 (soil dumping operation completion angle γ1r). That is, the timing when the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r and the timing when the rotating body 7 starts to rotate are approximately the same. This allows a smooth transition from the earth-discharging operation to the return operation.

[0102] At time T3, when the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r, return control of the work implement 2 is started. When the revolving body 7 and the work implement 2 perform the return operation and reach a state S22 in which the tip of the bucket 10 reaches the return completion position RP2, the return operation is completed.

[0103] According to the above-described first embodiment, the following advantageous effects are achieved.

[0104] (1) A hydraulic excavator (working machine) 1 includes a traveling body 5, a rotating body 7 provided so as to be rotatable with respect to the traveling body 5, and a working device 2 attached to the rotating body 7 and having a boom 8, an arm 9, and a bucket 10. The hydraulic excavator 1 also includes an attitude detection device 53 that detects the attitude of the rotating body 7 and the attitude of the working device 2 including the ground angle γ of the bucket 10, and an object detection device (vessel position detection device) 54 that detects the position of a loading platform (vessel) 201 of a loading machine 200 onto which an excavated material excavated by the working device 2 is loaded. The hydraulic excavator 1 also includes a control device 40 that performs automatic rotation control to automatically rotate at least the rotating body 7 to a rotation completion angle, which is a target rotation angle, based on the detection results of the attitude detection device 53 and the object detection device 54. The rotation start angle, which is the rotation angle at which the automatic rotation control is started, is the rotation angle θsw at the transport start position CP1 in the transport operation, and is the rotation angle θsw at the return start position RP1 in the return operation. The rotation completion angle, which is the rotation angle at which the automatic rotation control is completed, is the rotation angle θsw at the transport completion position CP2 in the transport operation, and is the rotation angle θsw at the return completion position RP2 in the return operation. The control device 40 judges whether or not a rotation start condition for starting the automatic rotation control of the rotating body 7 is satisfied based on the rotation operation state of the rotating body 7 and the operation state of the working device 2. When the control device 40 judges that the rotation start condition is satisfied, it outputs a rotation operation start command to start rotating the rotating body 7 toward the rotation completion angle at the timing when the rotation start condition is satisfied, regardless of whether the working device 2 is in an operating state or not.

[0105] When the rotation start condition is satisfied during the excavation operation, the control device 40 outputs a rotation operation start command to start the transport control of the rotating body 7. As a result, the rotating body 7 actually starts to rotate at the same time as the working device 2 reaches the excavation operation completion posture, or immediately thereafter. Therefore, according to this embodiment, the transition from the excavation operation to the transport operation can be made smooth. Furthermore, when the rotation start condition is satisfied during the soil dumping operation, the control device 40 outputs a rotation operation start command to start the return control of the rotating body 7. As a result, the rotating body 7 actually starts to rotate at the same time as the working device 2 reaches the soil dumping operation completion posture, or immediately thereafter. Therefore, according to this embodiment, the transition from the soil dumping operation to the return operation can be made smooth. In other words, according to this embodiment, in the excavation and loading operation, the transition from the state in which the working device 2 is operating alone to the operation requiring the rotation operation can be made smoothly. As a result, the productivity (work efficiency) at the work site can be improved.

[0106] (2) The control device 40 calculates the ground angle γ of the bucket 10 based on the detection result of the attitude detection device 53. The control device 40 automatically operates the work implement 2 in each of the excavation operation and the soil-discharging operation until the ground angle γ of the bucket 10 becomes the operation completion angle γ1. The control device 40 determines whether or not the rotation start condition is satisfied in a state in which the rotation operation of the rotating body 7 has stopped and the work implement 2 is operating automatically so that the ground angle γ of the bucket 10 approaches the operation completion angle γ1. This configuration can smooth the transition from the automatic excavation operation to the automatic transport operation, and the transition from the automatic soil-discharging operation to the automatic return operation.

[0107] (3) When the control device 40 outputs a rotation operation start command at the current time, if it predicts that the rotating body 7 will start rotating after the ground angle γ of the bucket 10 reaches the operation completion angle γ1, the control device 40 determines that the rotation start condition is met. The control device 40 determines that the rotation start condition is not met until the above prediction is made. According to this configuration, the rotating body 7 actually starts rotating after the ground angle γ of the bucket 10 reaches the operation completion angle γ1. In other words, according to this configuration, it is possible to appropriately prevent the rotating body 7 from actually starting to rotate before the ground angle γ of the bucket 10 reaches the operation completion angle γ1.

[0108] (4) The control device 40 calculates the first time t1 from when the rotation operation start command is output until the operation of the rotating body 7 starts. The control device 40 calculates the second time t2 from the current time until the ground angle γ of the bucket 10 reaches the operation completion angle γ1. The control device 40 determines that the rotation start condition is met when the second time t2 is shorter than the first time t1. In other words, the control device 40 considers that the above prediction has been made. The control device 40 determines that the rotation start condition is not met when the second time t2 is equal to or longer than the first time t1. In this configuration, the control device 40 repeatedly calculates the second time t2 based on the current attitude of the working implement 2. Therefore, it is possible to more appropriately prevent the rotating body 7 from actually starting to rotate before the ground angle γ of the bucket 10 reaches the operation completion angle γ1.

[0109] <Modification 1 of the First Embodiment> In the first embodiment, an example was described in which the control contents when transitioning from an excavation operation to a transport operation are the same as the control contents when transitioning from an earth dumping operation to a return operation. However, the present invention is not limited to this. Below, with reference to Figs. 13 to 16, modified examples of the control contents when transitioning from an earth dumping operation to a return operation will be described.

[0110] 13 is a schematic plan view showing a state in which the hydraulic excavator 1 according to the first modification of the first embodiment transitions from the earth-discharging operation to the return operation. The control device 40 according to the first embodiment outputs a swing start command during the earth-discharging operation so that the rotation of the revolving body 7 starts after the work device 2 reaches the earth-discharging operation completion posture. In contrast, the control device 40 according to the first modification outputs a swing start command during the earth-discharging operation so that the rotation of the revolving body 7 starts before the work device 2 reaches the earth-discharging operation completion posture and the bucket 10 starts to go out of the platform 201 after the work device 2 reaches the earth-discharging operation completion posture.

[0111] Therefore, in this first modification, the work implement 2 continues the earth-discharging operation even while the rotating body 7 is rotating so that the bucket 10 reaches the rear end of the platform 201 from the return start position RP1, as shown in Fig. 13. Then, the earth-discharging operation by the work implement 2 is completed just before the bucket 10 starts to move out of the platform 201. Thereafter, the rotating body 7 and the work implement 2 are controlled so that the control point of the bucket 10 moves along a target path RPT connecting the position RP3 and the return completion position RP2.

[0112] Fig. 14 is a diagram similar to Fig. 11, and is a flowchart showing an example of the processing executed by the control device 40 according to the first modified example of the first embodiment, showing the flow of processing from the start of the soil releasing operation to the completion of the return operation. In the flowchart of Fig. 14, processing of step S113B is executed instead of the processing of step S113 in the flowchart of Fig. 11. Also, in the flowchart of Fig. 14, processing of step S111B is added between steps S110 and S112 in the flowchart of Fig. 11.

[0113] As shown in Fig. 14, in this modification, when the calculation process of the first time t1r is completed in step S110, the process proceeds to step S111B. In step S111B, the swing start determination unit 43 calculates the third time t3r based on the mathematical model of the hydraulic excavator 1 stored in the storage device, the attitude of the hydraulic excavator 1 calculated by the attitude calculation unit 41, and the position information of the bed 201 calculated by the object position calculation unit 42. The third time t3r corresponds to the time from when the revolving unit 7 actually starts to swing until when the bucket 10 starts to go out of the bed 201. In other words, the third time t3r corresponds to the time until the revolving unit 7 reaches the rear end of the bed 201.

[0114] The swing start determination unit 43 may calculate the third time t3r by using a data table that specifies the relationship between the swing angle θsw1 of the bucket 10 from the return start position RP1 to the rear end of the platform 201 and the third time t3r. FIG. 15 is a diagram showing a data table of the third time t3r. The data table of the third time t3r is determined in advance by experiments or the like and stored in a storage device. The swing start determination unit 43 calculates the swing angle θsw1 from the current position of the bucket 10 to the position where the bucket 10 reaches the rear end of the platform 201 based on the attitude of the hydraulic excavator 1 and the relative position of the platform 201 with respect to the hydraulic excavator 1. The swing start determination unit 43 refers to the data table of FIG. 15 and calculates the third time t3r based on the calculated swing angle θsw1.

[0115] 14, when the calculation process of the third time t3r is completed, the process proceeds to step S112, where the second time t2r is calculated. When the calculation process of the second time t2r is completed in step S112, the process proceeds to step S113B.

[0116] The process of step S113B is a process for judging whether or not the swing start condition is satisfied. In step S113B, the swing start judgment unit 43 compares the sum of the first time t1r and the third time t3r with the second time t2r. By this comparison, the swing start judgment unit 43 judges whether or not the swing of the swing body 7 will start before the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r, and whether or not the bucket 10 will start to go out of the loading platform 201 after the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r, when the swing operation start command is output at the current time.

[0117] If the sum of the first time t1r and the third time t3r is equal to or less than the second time t2r, the turn start determination unit 43 determines that the turn start condition is not satisfied and returns the process to step S112. If the sum of the first time t1r and the third time t3r is greater than the second time t2r, the turn start determination unit 43 determines that the turn start condition is satisfied, sets the return turn flag to ON, and proceeds to step S114.

[0118] In other words, in this modified example, if it is predicted that the bucket 10 will begin to pass the end of the platform 201 immediately after the ground angle γ of the bucket 10 reaches the discharge operation completion angle γ1r (Yes in step S113B), return control of the rotating body 7 is started (step S114).

[0119] The operation when transitioning from the earth-discharging operation to the return operation in this modified example will be described using Figures 13 and 16. Figure 16 is a diagram similar to Figure 12, and is a diagram showing time-series changes in the ground angle γ of the bucket 10, the presence or absence of output of a swing operation command (ON / OFF), and the swing angle θsw when transitioning from the earth-discharging operation to the return operation in modified example 1 of the first embodiment.

[0120] In this modification, at time Tr2 when a certain time has elapsed from state S20 when the soil dumping operation is started, the swing start condition is satisfied (Yes in step S113B in FIG. 14), and the automatic swing control of the swing body 7 is started. On the other hand, at time Tr1 before time Tr2, the swing start condition is not satisfied (No in step S113B in FIG. 14), so the automatic swing control of the swing body 7 is not started. In this modification, the swing body 7 actually starts to swing at time Tr3 before time Tr4 when the ground angle γ of the bucket 10 reaches the soil dumping operation completion angle γ1r. Therefore, due to the swing of the swing body 7, the bucket 10 moves toward the rear end of the bed 201 while performing a dump operation above the bed 201. When the swing angle θsw increases to a predetermined swing angle θsw1, the state becomes S21 in which the bucket 10 has reached the rear end of the bed 201. At this time, it is preferable that the position RP3 of the tip of the bucket 10 be set at a position higher than the upper edge of the platform 201.

[0121] In this modified example, the timing when the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r coincides with the timing when the bucket 10 reaches the rear end of the platform 201. When the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r at time Tr4, a state S21 is reached, and return control of the work implement 2 is started. The revolving body 7 and the work implement 2 perform a return operation, and when the tip of the bucket 10 reaches the return completion position RP2, a state S22, is reached, the return operation is completed.

[0122] According to the first modification of the first embodiment, in addition to the same effects as those of the first embodiment, the following advantageous effects are achieved.

[0123] (5) When the control device 40 outputs a rotation start command at the present time in a state in which the working device 2 is performing an earth discharge operation (discharging operation) to discharge the excavated material in the bucket 10 above the loading platform 201, if it predicts that the rotation of the rotating body 7 will start before the ground angle γ of the bucket 10 reaches the earth discharge operation completion angle (operation completion angle) γ1r and that the bucket 10 will start to go out of the loading platform 201 after the ground angle γ of the bucket 10 reaches the earth discharge operation completion angle γ1r, the control device 40 judges that the rotation start condition is not satisfied until the above prediction is made. In this modification, the predetermined posture for outputting the rotation start command when the earth discharge operation is being performed is different from that of the above embodiment. The predetermined posture according to this modification is a posture in which, if a rotation start command is output when the working device 2 is in that posture, the working device 2 will start to go out of the loading platform 201 immediately after the working device 2 reaches the earth discharge operation completion posture. In this modified example, since the revolving body 7 can actually be moved above the platform 201 before the soil releasing operation is completed, it is possible to improve productivity more than in the above embodiment.

[0124] (6) The control device 40 calculates the first time t1r from the output of the rotation operation start command to the start of the operation of the rotating body 7. The control device 40 calculates the second time t2r from the current time until the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r. The control device 40 calculates the third time t3r from the start of the operation of the rotating body 7 to the time when the bucket 10 starts to go outside the loading platform 201. The control device 40 determines that the rotation start condition is met when the second time t2r becomes shorter than the sum of the first time t1r and the third time t3r. In this configuration, the control device 40 repeatedly calculates the second time t2r based on the current posture of the working device 2. Therefore, it is possible to appropriately prevent the rotating body 7 from going outside the loading platform 201 before the working device 2 reaches the earth-discharging operation completion posture.

[0125] <Modification 2 of the First Embodiment> The method of calculating the second time t2r is not limited to the above example.

[0126] <Modification 2-1 of the First Embodiment> For example, the control device 40 may calculate the second time t2r using a data table (hereinafter also referred to as a second time characteristic table) that specifies the relationship between the ground angle γ of the bucket 10 and the time (second time t2r) until the discharge of the excavated material in the bucket 10 is completed when the dumping operation is continued from the ground angle γ. The time until the discharge of the excavated material in the bucket 10 is completed is affected by the soil quality (viscosity, grain size) of the excavated material. For this reason, the control device 40 may correct the second time characteristic table based on the soil quality of the excavated material. The soil quality of the excavated material is input to the control device 40 by the input device 57. The control device 40 refers to the corrected second time characteristic table and calculates the second time t2r based on the ground angle γ of the bucket 10.

[0127] <Modification 2-2 of the First Embodiment> Furthermore, the control device 40 may calculate the time from the start to the completion of the dumping operation (hereinafter, the required dumping time) based on the behavior of the transported material (excavated material) in the bucket 10 during the first dumping operation of the excavation and loading cycle using the object detection device 54, and use this to control the transition from the second or subsequent dumping operation to the return operation of the excavation and loading cycle. The behavior of the transported material in the bucket 10 is, for example, a change in the area of ​​the transported material in the bucket 10 in an image captured by a stereo camera serving as the object detection device 54. During the first dumping operation of the excavation and loading cycle, the control device 40 determines that the dumping operation is completed and calculates the required dumping time when the area of ​​the transported material in the bucket 10 detected by the object detection device 54 becomes equal to or less than a predetermined value.

[0128] The timing of completion of the soil-discharging operation may be instructed to the control device 40 by the operator operating the input device 57. For example, in the first soil-discharging operation of the excavation and loading cycle, the control device 40 stores the time from the start of the soil-discharging operation to the time the operator operates the input device 57 as the required release time.

[0129] The control device 40 calculates the second time t2r by subtracting the elapsed time from the start time of the soil releasing operation from the required releasing time in the second and subsequent excavation and loading cycles.

[0130] In this way, the control device 40 according to this modified example calculates the required discharge time, which is the time from the start time to the completion time of the operation of discharging the excavated material in the bucket 10, during the first earth-discharging operation. During the second and subsequent earth-discharging operations, the control device 40 calculates the second time t2r by subtracting the elapsed time from the start time of the operation of discharging the excavated material in the bucket 10 from the required discharge time. With this configuration, the control device 40 can output a swing operation start command at an appropriate timing, regardless of individual differences, etc., of the hydraulic excavator 1 performing the work.

[0131] <Second embodiment> A hydraulic excavator 1 according to a second embodiment of the present invention will be described with reference to Figs. 17 to 21. Configurations that are the same as or equivalent to those described in the first embodiment are given the same reference symbols, and differences will be mainly described. A control device 240 according to the second embodiment acquires the weight of the transported material (excavated material such as earth and sand) in the bucket 10, and judges whether or not the swing start condition is satisfied based on the acquired weight. When the weight of the excavated material in the bucket 10 reaches a predetermined weight, the control device 240 judges that the swing start condition is satisfied. When the weight of the excavated material in the bucket 10 does not reach the predetermined weight, the control device 240 judges that the swing start condition is not satisfied. The configuration of the hydraulic excavator 1 according to the second embodiment and the function of the control device 240 will be described in detail below.

[0132] FIG. 17 is a functional block diagram of the control device 240 according to the second embodiment. The hydraulic excavator 1 according to the second embodiment includes a transported object information acquisition device 258. The transported object information acquisition device 258 calculates the weight of the transported object stored in the bucket 10. The transported object information acquisition device 258 includes, for example, a pressure sensor (not shown) that detects the pressure of the hydraulic cylinders (11 to 13) and a calculation device that calculates the weight of the transported object based on the detection result of the pressure sensor and the detection result of the attitude detection device 53. Note that the configuration of the transported object information acquisition device 258 is not limited to this. The transported object information acquisition device 258 may be a weight sensor that directly detects the weight of the transported object in the bucket 10. In addition, in this embodiment, an example in which the calculation device of the transported object information acquisition device 258 is provided separately from the control device 240 will be described, but the function of the calculation device of the transported object information acquisition device 258 may be provided in the control device 240.

[0133] An example of the flow of processing executed by the control device 240 according to the second embodiment will be described with reference to Figures 18 and 19. Figure 18 is a flowchart showing an example of processing by the control device 240 according to the second embodiment, showing the flow of processing from the start of an excavation operation to the completion of a transport operation. Figure 19 is a flowchart showing an example of processing by the control device 240 according to the second embodiment, showing the flow of processing from the start of a release operation to the completion of a return operation.

[0134] In the flowchart of Fig. 18, the process of step S201 is executed instead of the processes of steps S102 to S104 in the flowchart of Fig. 10. In the flowchart of Fig. 19, the process of step S202 is executed instead of the processes of steps S110 to S113 in the flowchart of Fig. 11.

[0135] As shown in Fig. 18, excavation control is started in step S101. As a result, the hydraulic excavator 1 is in a state where the rotation of the rotating body 7 is stopped and the working implement 2 is operating to excavate the excavation material. In the second embodiment, excavation control is performed so that the weight (excavation volume) W of the excavation material stored in the bucket 10 reaches the target excavation volume Wt. The target excavation volume Wt is a target value for the weight of the excavation material to be stored in the bucket 10, which is determined in advance and stored in the storage device.

[0136] The process of the next step S201 is a process for judging whether or not the swing start condition is satisfied. In step S201, the swing start judgment unit 43 judges whether or not the excavated material is stored in the bucket 10 at a predetermined ratio P1 or more with respect to the target excavation volume Wt based on the weight W of the transported material acquired by the transported material information acquisition device 258. The predetermined ratio P1 is determined in advance and stored in the storage device. The predetermined ratio P1 is, for example, a value of 90% or more. The predetermined ratio P1 may be changed by operating the input device 57. If it is judged that the excavated material is stored in the bucket 10 at a predetermined ratio P1 or more with respect to the target excavation volume Wt, the process proceeds to step S105. The process of step S201 is repeatedly executed at a predetermined calculation cycle until a positive judgment is made.

[0137] Specifically, the swing start determination unit 43 acquires the weight W of the transported object from the transported object information acquisition device 258 at every predetermined calculation cycle. When an excavation operation is performed, the weight W of the transported object in the bucket 10 increases over time. When the weight W of the transported object becomes equal to or greater than a predetermined weight W1, the swing start determination unit 43 determines that the swing start condition is met and proceeds to step S105. The predetermined weight W1 is the weight of the transported object equivalent to a predetermined ratio P1 of the target excavation amount Wt, and is calculated by the swing start determination unit 43.

[0138] The processing in steps S105 to S108 in FIG. 18 is similar to that in the first embodiment (see FIG. 10), and therefore a description thereof will be omitted.

[0139] 19, soil release control is started in step S109. As a result, the hydraulic excavator 1 is in a state where the rotation operation of the rotating body 7 is stopped and the work implement 2 is operating to release the excavated material.

[0140] The process of the next step S202 is a process for judging whether or not the turning start condition is satisfied. In step S202, the turning start judgment unit 43 judges whether or not the weight W of the transported object has decreased by a predetermined ratio P2 or more with respect to the weight W0 before the earth-releasing operation, based on the weight W of the transported object acquired by the transported object information acquisition device 258. The process of step S202 can also be said to be a process for judging whether or not the ratio Pd of the weight W of the transported object decreased with respect to the weight W0 before the earth-releasing operation (hereinafter also referred to as the reduction ratio of the transported object) has become equal to or more than the predetermined ratio P2.

[0141] The predetermined percentage P2 is determined in advance and stored in the storage device. The predetermined percentage P2 is, for example, a value of about 80 to 90%. The predetermined percentage P2 may be changed by operating the input device 57.

[0142] The swing start determination unit 43 stores the weight W of the transported object when the operation transition condition from the excavation operation to the transport operation is satisfied as the weight W0 before the dumping operation. If it is determined that the weight W of the transported object has decreased by a predetermined percentage P2 or more with respect to the weight W0 before the dumping operation, the process proceeds to step S114. The process of step S202 is repeatedly executed at a predetermined calculation cycle until a positive determination is made.

[0143] Specifically, the swing start determination unit 43 obtains information on the weight W of the transported object from the transported object information acquisition device 258 at every predetermined calculation cycle. When the dumping operation is performed, the weight W of the transported object in the bucket 10 decreases over time. When the weight W of the transported object becomes equal to or less than a predetermined weight W2, the control device 240 determines that the swing start condition is met and proceeds to step S114. The predetermined weight W2 is the value (W2=W0-W0×P2) obtained by subtracting the weight W0 before the dumping operation from the weight W0 released, i.e., a predetermined ratio P2 of the weight W0 before the dumping operation.

[0144] The processes in steps S114 to S117 in FIG. 19 are similar to those in the first embodiment (see FIG. 11), and therefore will not be described.

[0145] Hereinafter, main operations of the hydraulic excavator 1 according to the second embodiment will be described with reference to Fig. 20 and Fig. 21. First, operations during transition from an excavation operation to a transport operation will be described with reference to Fig. 20. Fig. 20 is a diagram showing time series changes in the weight (excavation amount) W of the transported object in the bucket 10, the presence or absence (ON / OFF) of a swing operation command, and the swing angle θsw when the operation transitions from an excavation operation to a transport operation. The horizontal axis in Fig. 20(a) to (c) indicates time. The vertical axis in Fig. 20(a) indicates the weight (excavation amount) W of the transported object in the bucket 10. The vertical axis in Fig. 20(b) indicates the presence or absence of a swing operation command output, and the vertical axis in Fig. 20(c) indicates the swing angle θsw. Note that the swing angle θsw is shown as a graph in which the position at which the excavation operation is started is set as a reference position, and increases in a positive direction from the reference position to the excavation operation completion angle.

[0146] As shown in FIG. 20, at time Tc22 when a certain time has elapsed since the start of the excavation operation, the rotation start condition is satisfied (Yes in step S201 in FIG. 18), and the automatic rotation control of the rotating body 7 is started. On the other hand, at time Tc21, which is before time Tc22, the rotation start condition is not satisfied (No in step S201 in FIG. 18), and the automatic rotation control of the rotating body 7 is not started. The automatic rotation control of the rotating body 7 is started (a rotation operation start command is output) at a stage (time Tc22) before time Tc23 when the weight W of the transported material in the bucket 10 reaches the target excavation volume Wt. As a result, the rotating body 7 actually starts to rotate immediately after the weight W of the transported material in the bucket 10 reaches the target excavation volume Wt. In other words, the timing when the weight W of the transported material in the bucket 10 reaches the target excavation volume Wt and the timing when the rotating body 7 starts to rotate are approximately the same. As a result, the transition from the excavation operation to the transport operation is performed smoothly.

[0147] Next, the operation when transitioning from the dumping operation to the return operation will be described with reference to FIG. 21. FIG. 21 is a diagram showing the time series changes in the reduction rate Pd of the transported goods in the bucket 10, the presence or absence (ON / OFF) of a swing operation command, and the swing angle θsw when transitioning from the dumping operation to the return operation. The horizontal axis in FIG. 21(a) to (c) indicates time. The vertical axis in FIG. 21(a) indicates the reduction rate Pd [%] of the transported goods. The vertical axis in FIG. 21(b) indicates the presence or absence of the swing operation command output, and the vertical axis in FIG. 21(c) indicates the swing angle θsw. Note that the swing angle θsw is shown as a graph in which the position where the dumping operation is started is set as a reference position, and increases in the positive direction from the reference position to the dumping operation completion angle.

[0148] As shown in FIG. 21, at time Tr22 when a certain time has elapsed since the start of the soil dumping operation, the swing start condition is satisfied (Yes in step S202 in FIG. 19), and the automatic swing control of the swing body 7 is started. On the other hand, at time Tr21 before time Tr22, the swing start condition is not satisfied (No in step S202 in FIG. 19), so the automatic swing control of the swing body 7 is not started. The automatic swing control of the swing body 7 is started (a swing operation start command is output) at a stage (time Tr22) before time Tr23 when the reduction rate Pd of the transported goods reaches 100%. As a result, the swing body 7 actually starts to swing immediately after the reduction rate Pd of the transported goods reaches 100%. In other words, the timing when the reduction rate Pd of the transported goods reaches 100% and the timing when the swing body 7 starts to swing are approximately the same. As a result, the transition from the soil dumping operation to the return operation is performed smoothly.

[0149] In this way, the control device 240 according to the second embodiment acquires the weight W of the transported object (excavated object) in the bucket 10 from the transported object information acquisition device 258. The control device 240 determines that the swing start condition is satisfied when the acquired weight W of the transported object in the bucket 10 reaches a predetermined weight. The control device 240 determines whether the swing start condition is satisfied when the swing operation of the revolving body 7 is stopped and the working device 2 is operating to excavate the excavated object. The control device 240 determines that the swing start condition is satisfied when the weight W of the excavated object in the bucket 10 increases to a predetermined weight W1, and outputs a swing operation start command (steps S201 and S105 in FIG. 18). The control device 240 determines whether the swing start condition is satisfied when the swing operation of the revolving body 7 is stopped and the working device 2 is operating to release the excavated object. When the weight W of the excavated material in the bucket 10 is reduced to a predetermined weight W2 by releasing a weight of a predetermined ratio P2 from before the release operation, the control device 240 determines that the swing start condition is met and outputs a swing operation start command (steps S202, S114 in FIG. 19). According to the second embodiment, the same effects as those of the first embodiment are achieved.

[0150] Furthermore, according to the second embodiment, the transported object information acquisition device 258 calculates the weight W of the transported object (excavated object) in the bucket 10, so that the calculation load of the control device 240 can be reduced.

[0151] <Modification 1 of the second embodiment> 22, there is a correlation between the reduction rate Pd of the transported goods and the ground angle γ of the bucket 10. As the ground angle γ of the bucket 10 approaches the discharge completion angle, the reduction rate Pd of the transported goods increases. Therefore, when the ground angle γ of the bucket 10 reaches the ground angle (ground angle threshold value) γ2 corresponding to the predetermined rate P2, the rotation start determination unit 43 may determine that the rotation start condition is met and output a rotation operation start command.

[0152] In this modification, the predetermined rate P2 may be changed by operating the input device 57. In this case, the storage device stores a ground angle conversion table T (see FIG. 22), which is a data table that defines the relationship between the reduction rate Pd of the transported goods and the ground angle γ of the bucket 10. When the turning start determination unit 43 acquires information on the new predetermined rate P2 from the input device 57, it refers to the ground angle conversion table T and calculates the ground angle (ground angle threshold value) γ2 of the bucket 10 that corresponds to the new predetermined rate P2.

[0153] As described above, the hydraulic excavator 1 according to this modification includes the input device 57 that can input the predetermined ratio P2. The control device 240 according to this modification also includes a ground angle conversion table T that is a data table that defines the relationship between the ratio of the weight of the excavated material released from the bucket 10 to the weight W0 of the excavated material before it is released from the bucket 10 (the reduction ratio of the transported material) Pd and the ground angle γ of the bucket 10. The control device 240 refers to the ground angle conversion table T and determines the ground angle of the bucket 10 that corresponds to the predetermined ratio P2 input by the input device 57 as the ground angle threshold value γ2. When the ground angle γ of the bucket 10 reaches the ground angle threshold value γ2, the control device 240 determines that the swing start condition is met and outputs a swing operation start command. With this configuration, the operator can adjust the timing of the swing operation by operating the input device 57.

[0154] <Modification 2 of the second embodiment> In the configuration according to the first modified example of the second embodiment, the control device 240 may further correct and use the ground angle conversion table T. By the control device 240 correcting the ground angle conversion table T, it is possible to more appropriately set the ground angle γ2 of the bucket 10 corresponding to the predetermined ratio P2.

[0155] <Modification 2-1 of the second embodiment> For example, the swing start determination unit 43 may correct the ground angle conversion table T, which is a reference data table, based on the actual data of the hydraulic excavator 1. FIG. 23 is a diagram showing the corrected ground angle conversion tables Tc1 and Tc2. For example, in a state where the dumping operation is being performed, the ground angle conversion table T may be corrected based on time-series data of the weight W of the transported object calculated by the transported object information acquisition device 258, the ground angle γ of the bucket 10 calculated by the attitude calculation unit 41, and the weight W0 of the transported object before the dumping operation. In this way, for example, the corrected ground angle conversion table Tc1 is obtained. The control device 240 refers to the corrected ground angle conversion table Tc1 and calculates the ground angle threshold value γc21 of the bucket 10 for the input predetermined ratio P2. When the ground angle γ of the bucket 10 reaches the ground angle threshold value γc21 during the dumping operation, the control device 240 determines that the swing start condition is established and outputs a swing operation start command.

[0156] In this way, the control device 240 according to this modification acquires actual machine data (weight W of the excavated material and ground angle γ of the bucket) when the work implement 2 is performing an earth-discharging operation, and determines the ground angle threshold value that defines the swing start condition based on the acquired actual machine data. With this configuration, the control device 240 can output a swing operation start command at an appropriate timing, regardless of individual differences, etc. of the hydraulic excavator 1 performing the work.

[0157] <Modification 2-2 of the second embodiment> Furthermore, the greater the viscosity of the soil of the excavated material, the more difficult it is to release the transported material from the bucket 10. Therefore, the swing start determination unit 43 may correct the ground angle conversion table T based on the soil property of the transported material. The hydraulic excavator 1 according to this modified example is equipped with an input device 57 that can input soil property such as the viscosity of the excavated material. The operator operates the input device 57 to input the predetermined ratio P2 and the viscosity of the excavated material to the control device 240.

[0158] When the input viscosity is greater than the reference viscosity value stored in the storage device, the control device 240 corrects the ground angle conversion table T so that the rate of change of the reduction rate Pd with respect to the ground angle γ becomes smaller. This results in a corrected ground angle conversion table Tc2. The control device 240 refers to the corrected ground angle conversion table Tc2 and calculates the ground angle threshold value γc22 of the bucket 10 for the input predetermined rate P2. Note that the soil quality of the excavated material is not limited to viscosity, and may be granularity.

[0159] In this way, the control device 240 according to this modification corrects the ground angle conversion table T based on the soil quality of the excavated object input by the input device 57. With this configuration, even if the soil quality of the excavated object changes, such as when the excavation work site is changed, the control device 240 can output a turning operation start command at an appropriate timing.

[0160] <Modification 2-3 of the second embodiment> Furthermore, if the angular velocity of the bucket 10 is high, the reduction rate Pd of the transported goods at a certain ground angle γ becomes smaller than expected. Therefore, the turning start determination unit 43 may correct the ground angle conversion table T based on the ground angular velocity of the bucket 10. The angular velocity of the bucket 10 is calculated by the attitude calculation unit 41. When the angular velocity of the bucket 10 is greater than a reference value, the control device 240 corrects the ground angle conversion table T so that the rate of change of the reduction rate Pd with respect to the ground angle γ becomes smaller. As a result, a corrected ground angle conversion table Tc2 is obtained.

[0161] <Modification 3 of the second embodiment> The control device 240 may calculate a reduction rate Pd of the transported object in the bucket 10 in the soil releasing operation (discharging operation) based on the behavior of the transported object (excavated object) in the bucket 10 detected by the object detection device 54. The behavior of the transported object in the bucket 10 is, for example, a change in the area of ​​the transported object in the bucket 10 in an image captured by a stereo camera serving as the object detection device 54. The control device 240 may also calculate a reduction rate Pd of the transported object based on the shape of the transported object (excavated object) discharged to the loading platform 201 detected by the object detection device 54. When the transported object is discharged to the loading platform 201, a pile of the transported object is formed on the loading platform 201 by the amount of the transported object discharged. Therefore, the control device 240 can estimate how much of the transported object has been discharged from the shape of the transported object detected by the object detection device 54. When the reduction rate Pd of the transported object reaches a predetermined rate P2, the control device 240 determines that a rotation start condition is established and outputs a rotation operation start command.

[0162] In this manner, the control device 240 according to this modification determines whether or not the turning start condition is met based on the behavior of the excavated material in the bucket 10 detected by the object detection device 54, or the shape of the excavated material released onto the loading platform 201 detected by the object detection device 54. With this configuration, the transported object information acquisition device 258 can be omitted.

[0163] <Third embodiment> A hydraulic excavator 1 according to a third embodiment of the present invention will be described with reference to Figs. 24 to 26. Configurations that are the same as or equivalent to those described in the first embodiment are given the same reference symbols, and differences will be mainly described. In the first embodiment, an example in which the excavation operation, transport operation, soil-discharging operation, and returning operation are performed automatically has been described. In contrast, in the third embodiment, an example in which the excavation operation and soil-discharging operation are performed manually, and the transport operation and returning operation are performed automatically will be described.

[0164] FIG. 24 is a functional block diagram of a control device 340 according to the third embodiment. The hydraulic excavator 1 according to this embodiment is configured to automatically perform a transport operation after an excavation operation performed manually by an operator. The control device 340 outputs a command to start a swing operation for the transport operation at a timing instructed by the operator. The hydraulic excavator 1 according to this embodiment is also configured to automatically perform a return operation after an earth-releasing operation performed manually by an operator. The control device 340 outputs a command to start a swing operation for the return operation at a timing instructed by the operator.

[0165] The control selection switch 324 has a function of selecting a semi-automatic mode in addition to the function of the control selection switch 24 described in the first embodiment. When the semi-automatic mode is set, the control device 340 controls the operation of the work device 2 in accordance with the operation device 20 during excavation and soil discharge operations. Furthermore, the control device 340 controls the operation of the work device 2 and the revolving body 7 in accordance with the target route set by the control device 340, regardless of the operation of the operation device 20, during transport and return operations.

[0166] An operation transition determination unit 349 according to the third embodiment sets the control mode to any one of automatic mode, manual mode, and semi-automatic mode, based on an operation command from the control selection switch 324. Furthermore, when the automatic mode is set, the operation transition determination unit 349 determines that the operation transition condition is met when the tip of the bucket 10 reaches the completion position of the target path, similarly to the first embodiment.

[0167] The operation transition determination unit 349 determines that the operation transition condition from the excavation operation to the transport operation is satisfied when the semi-automatic mode is set and the work operation device 29 is returned to the neutral position after the excavation operation by the work operation device 29 is performed. The operation transition determination unit 349 also determines that the operation transition condition from the soil-discharging operation to the return operation is satisfied when the semi-automatic mode is set and the work operation device 29 is returned to the neutral position after the soil-discharging operation by the work operation device 29 is performed. The operation transition determination unit 349 determines that the work operation device 29 is returned to the neutral position after the excavation operation or soil-discharging operation by the work operation device 29 is performed when any of the arm operation amount, boom operation amount, and bucket operation amount detected by the operation amount sensors 52a, 52c, and 52d of the operation detection device 56 becomes equal to or greater than the operation determination threshold and then any of the arm operation amount, boom operation amount, and bucket operation amount becomes equal to or less than the neutral determination threshold.

[0168] The turning start determination unit 343 according to the third embodiment determines whether the current motion state is an excavation motion, a transport motion, a soil dumping motion, or a return motion, based on the determination result of the motion transition determination unit 349. Furthermore, the turning start determination unit 343 determines that a turning operation has been performed when the amount of turning operation detected by the operation amount sensor 52b of the operation detection device 56 is equal to or greater than the operation determination threshold value.

[0169] The swing start determination unit 343 determines that the swing start condition is satisfied when a swing operation is performed while an excavation operation is being performed. The swing start determination unit 343 also determines that the swing start condition is satisfied when a swing operation is performed while an earth-discharging operation is being performed. In this way, in the third embodiment, the swing operation device 28 also functions as a swing start operation device that instructs the start of swing of the swing body 7 by automatic operation during an excavation operation or an earth-discharging operation.

[0170] An example of the flow of processing executed by the control device 340 according to the third embodiment will be described with reference to Figures 25 and 26. Figure 25 is a flowchart showing an example of processing by the control device 340 according to the third embodiment, showing the flow of processing from the start of an excavation operation to the completion of a transport operation. Figure 26 is a flowchart showing an example of processing by the control device 340 according to the third embodiment, showing the flow of processing from the start of a release operation to the completion of a return operation.

[0171] In the flowchart of Fig. 25, the processes of steps S301 and S302 are executed instead of the processes of steps S101 to S104 in the flowchart of Fig. 10. Also, in the flowchart of Fig. 25, the process of step S303 is executed instead of the processes of step S106 in the flowchart of Fig. 10. In the flowchart of Fig. 26, the processes of steps S304 and S305 are executed instead of the processes of steps S109 to S113 in the flowchart of Fig. 11. Also, in the flowchart of Fig. 26, the process of step S306 is executed instead of the processes of step S115 in the flowchart of Fig. 11.

[0172] 25, in step S301, when an operation is performed with control selection switch 24 to change the control mode to semi-automatic mode, operation transition determination unit 349 sets the control mode to semi-automatic mode. When the semi-automatic mode is set, actuator command unit 48 starts an excavation operation by the work device 2 based on a target speed corresponding to the amount of operation of the work operation device 29.

[0173] The process of the next step S302 is a process for judging whether or not a turning start condition is satisfied. In step S302, the turning start judgment unit 343 judges whether or not a turning operation has been performed. If a turning operation has been performed, the turning start judgment unit 343 judges that the turning start condition is satisfied, and proceeds to the process of step S105. The process of step S302 is repeatedly executed at a predetermined calculation cycle until a positive judgment is made. In other words, the control device 340 repeatedly executes the process of step S302 until a turning operation is performed.

[0174] In step S105, the transport control unit 45 outputs a swing operation start command for the transport operation of the swing body 7. In the next step S303, the operation transition determination unit 49 determines whether or not the operation transition condition from the excavation operation to the transport operation is satisfied. If the work operation device 29 is returned to the neutral position (in this embodiment, both the work operation right lever 22a and the work operation left lever 22b are in the neutral position), the operation transition determination unit 49 determines that the operation transition condition from the excavation operation to the transport operation is satisfied, and proceeds to step S107. If the work operation device 29 is not returned to the neutral position (in this embodiment, at least one of the work operation right lever 22a and the work operation left lever 22b is not in the neutral position), the operation transition determination unit 49 determines that the operation transition condition from the excavation operation to the transport operation is not satisfied. The process of step S303 is repeatedly executed at a predetermined calculation period until a positive determination is made.

[0175] The processes in steps S107 and S108 in FIG. 25 are similar to those in the first embodiment (see FIG. 10), and therefore will not be described.

[0176] When the transport operation is completed (step S108 in Fig. 25), the process proceeds to step S304 shown in Fig. 26. In step S304, the actuator command unit 48 starts the soil releasing operation by the work device 2 based on the target speed according to the operation amount of the work operation device 29.

[0177] The process of the next step S305 is a process for determining whether or not a turning start condition is satisfied, similar to the process of step S302. In step S305, the turning start determination unit 343 determines whether or not a turning operation has been performed. If a turning operation has been performed, the turning start determination unit 343 determines that the turning start condition is satisfied, and proceeds to the process of step S114. The process of step S305 is repeatedly executed at a predetermined calculation cycle until a positive determination is made. In other words, the control device 340 repeatedly executes the process of step S305 until a turning operation is performed.

[0178] In step S114, the transportation control unit 45 outputs a rotation operation start command for the return operation of the rotating body 7. In the next step S306, the operation transition determination unit 49 determines whether or not the operation transition condition from the soil release operation to the return operation is satisfied. If the work operation device 29 is returned to the neutral position (in this embodiment, both the work operation right lever 22a and the work operation left lever 22b are in the neutral position), the operation transition determination unit 49 determines that the operation transition condition from the soil release operation to the return operation is satisfied, and proceeds to step S116. If the work operation device 29 is not returned to the neutral position (in this embodiment, at least one of the work operation right lever 22a and the work operation left lever 22b is not in the neutral position), the operation transition determination unit 49 determines that the operation transition condition from the soil release operation to the return operation is not satisfied. The process of step S306 is repeatedly executed at a predetermined calculation period until a positive determination is made.

[0179] The processes in steps S116 and S117 in FIG. 26 are similar to those in the first embodiment (see FIG. 11), and therefore will not be described.

[0180] The main operations of the hydraulic excavator 1 according to the third embodiment will now be described. The operator operates the work operation device 29, causing the work device 2 to perform an excavation operation (step S301). When the excavation operation has progressed to a certain extent, the operator operates the swing operation device 28, causing the control device 340 to output a swing operation start command for a transport operation (steps S302, S105).

[0181] When the operator returns the work operating device 29 to the neutral position, the control device 340 determines that the excavation operation is completed, and operates the work device 2 along the target path CPT (steps S303, S107, S108).

[0182] After the automatic transport operation is completed, the operator operates the work operation device 29, and the work device 2 performs the earth releasing operation (step S304). When the earth releasing operation has progressed to a certain extent, the operator operates the turning operation device 28, and a turning operation start command for the return operation is output from the control device 340 (steps S305, S114, S117).

[0183] When the operator returns the work operation device 29 to the neutral position, the control device 340 determines that the earth releasing operation is completed, and operates the work device 2 along the target path RPT (steps S306, S116).

[0184] As described above, in the third embodiment, there are provided a swing operation device (swing start operation device) 28 that is operated by the operator to instruct the start of swing of the swing body 7, and a work operation device 29 that is operated by the operator to operate the work device 2. The control device 340 operates the work device 2 in response to the operation of the work operation device 29. The control device 340 determines whether or not a swing start condition is satisfied when the swing operation of the swing body 7 has stopped and the work device 2 is operating in response to the operation of the work operation device 29. The control device 340 determines that the swing start condition is satisfied when the swing operation device 28 instructs the start of swing of the swing body 7.

[0185] According to the third embodiment, while the operator is manually performing an excavation operation or a soil dumping operation using the work implement 2, a rotation operation start command for a transport operation or a return operation can be output from the control device 340 based on the operator's intention.

[0186] <Modification 1 of the third embodiment> The hydraulic excavator 1 according to the third embodiment has been described as an example in which the excavation operation and the soil dumping operation are performed based on the manual operation of the operator, and the transport operation and the return operation are performed automatically. However, the hydraulic excavator 1 may be configured to perform only the excavation operation based on the manual operation of the operator, and to perform the transport operation, soil dumping operation, and the return operation automatically. The hydraulic excavator 1 may be configured to perform only the soil dumping operation based on the manual operation of the operator, and to perform the excavation operation, transport operation, and the return operation automatically. The hydraulic excavator 1 may be configured to perform all of the excavation operation, transport operation, soil dumping operation, and return operation automatically. In this case, the hydraulic excavator 1 may be configured such that the operator instructs only the timing of outputting a swing operation start command for the transport operation and the return operation.

[0187] For example, the control device may execute the process of step S302 in Fig. 25 instead of the processes of steps S102 to S104 in Fig. 10. Also, the control device may execute the process of step S305 in Fig. 26 instead of the processes of steps S110 to S113 in Fig. 11.

[0188] The control device 340 according to this modified example judges whether or not the swing start condition is satisfied when the swing operation of the swing body 7 has stopped and the working device 2 is operating. The control device 340 judges that the swing start condition is satisfied when an instruction to start swinging the swing body 7 is given by the swing operation device 28. With this configuration, a swing operation start command for a transport operation or a return operation can be output from the control device 340 based on the intention of the operator not only during manual operation by the operator but also during an excavation operation or soil discharge operation by automatic operation by the control device 340.

[0189] <Modification 2 of the third embodiment> In the third embodiment, an example has been described in which the rotation start operation device that instructs the start of rotation of the rotating body 7 is the rotation operation device 28. However, the form of the rotation start operation device is not limited to this. For example, the rotation start operation device may be an operation device different from the operation devices 20 and 21, and may be an operation switch provided on the operation levers 22a and 22b.

[0190] The following modified examples are also within the scope of the present invention, and it is possible to combine the configurations shown in the modified examples with the configurations described in the above-mentioned embodiments, to combine the configurations described in the different embodiments above, or to combine the configurations described in the different modified examples below.

[0191] <Variation 1> In the above embodiment, an example has been described in which the vessel into which the excavated material excavated by the working device 2 is loaded is the bed 201 of a transport vehicle, but the present invention is not limited to this. The present invention may also be applied to a case in which the excavated material is loaded into a vessel provided on a loading machine such as a belt conveyor.

[0192] <Variation 2> In the above embodiment, a backhoe shovel with the bucket 10 attached to the tip of the arm 9 facing backward has been described as an example of a work machine, but the present invention is not limited to this. The work machine may be a loading shovel with the bucket 10 attached to the tip of the arm 9 facing forward.

[0193] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments. [Explanation of symbols]

[0194] 1...hydraulic excavator (working machine), 2...working device, 3...vehicle body, 5...traveling body, 6...swing hydraulic motor (hydraulic actuator), 7...swing body, 8...boom (driven member), 9...arm (driven member), 10...bucket (driven member), 11...boom cylinder (hydraulic cylinder, hydraulic actuator), 12...arm cylinder (hydraulic cylinder, hydraulic actuator), 13...bucket cylinder (hydraulic cylinder, hydraulic actuator), 14...boom angle sensor (posture sensor), 15...arm angle sensor (posture sensor), 17...bucket angle sensor (posture sensor) , 18... inclination angle sensor (attitude sensor), 19... turning angle sensor (attitude sensor), 20, 21... operation device, 24... control selection switch, 28... turning operation device (turn start operation device), 29... work operation device, 40... control device, 41... attitude calculation unit, 42... object position calculation unit, 43... turning start determination unit, 44... excavation control unit, 45... transportation control unit, 46... earth discharge control unit, 47... return control unit, 48... actuator command unit, 49... operation transition determination unit, 50... hydraulic drive system, 51... solenoid proportional valve, 52... operation amount sensor, 53... attitude detection device, 54... object detection device (vessel position detection device), 55... hydraulic oil temperature sensor, 56... operation detection device, 57... input device, 200... loading machine, 201... loading platform (tray, vessel), 240... control device, 258... transported object information acquisition device, 324... control selection switch, 340... control device, 343... turning start determination unit, 349... operation transition determination unit, 400... operation control unit, CP1... transportation start position, CP2... transportation completion position, CPT... target route, DP1... excavation start position, DP2... excavation completion position, DPT... target route, LP1... soil release start position, LP2... soil release completion position, LPT... target route, P1... predetermined ratio, P2... predetermined ratio, Pd...reduction rate of transported goods, RP1...return start position, RP2...return completion position, RPT...target route, T...ground angle conversion table (data table), t1, t1c, t1r...first time, t2, t2c, t2r...second time, t3r...third time, Tc1, Tc2...corrected ground angle conversion table, W...weight, W0...weight before dumping operation, W1, W2...predetermined weight, Wt...target excavation volume, γ...ground angle, γ1c...digging operation completion angle (operation completion angle), γ1r...dumping operation completion angle (operation completion angle), γ2, γc21, γc22...ground angle threshold, γt...target ground angle, θsw...turning angle

Claims

1. The vehicle and A slewing body is provided so as to be rotatable relative to the aforementioned traveling body, A working device attached to the aforementioned slewing body, having a boom, arm and bucket, A posture detection device for detecting the posture of the rotating body and the posture of the work device, A vessel position detection device for detecting the position of the vessel of a loading machine into which the excavated material excavated by the aforementioned work device is loaded, A work machine comprising: a control device that performs automatic rotation control to automatically rotate the rotating body to at least a target rotation angle, which is the rotation completion angle, based on the detection results of the attitude detection device and the vessel position detection device, The control device is Based on the rotational movement state of the rotating body and the operating state of the work device, it is determined whether or not the rotation start condition for initiating the automatic rotation control of the rotating body has been met. When it is determined that the aforementioned rotation start condition has been met, regardless of whether the work device is operating or not, a rotation start command is output at the moment the rotation start condition is met, causing the rotating body to start rotating toward the rotation completion angle. A work machine characterized by the following features.

2. In the work machine described in claim 1, The control device is Based on the detection results of the attitude detection device, the angle of the bucket relative to the ground is calculated. The work device is operated automatically until the angle of the bucket relative to the ground reaches the angle of completion of the operation. When the rotational movement of the rotating body has stopped and the working device is operating automatically so that the angle of the bucket relative to the ground approaches the angle at which the movement is completed, it is determined whether or not the rotation start condition has been met. A work machine characterized by the following features.

3. In the work machine described in claim 2, The control device determines that the conditions for starting the rotation have been met if it is predicted that the rotation of the rotating body will begin after the angle of the bucket relative to the ground reaches the angle of completion of the operation, when the rotation start command is output at the present time. A work machine characterized by the following features.

4. In the work machine described in claim 2, The control device is The first time from when the rotation start command is output until the rotation of the rotating body begins is calculated. The second time from the current point in time until the angle of the bucket relative to the ground reaches the angle at which the operation is completed is calculated. When the second time becomes shorter than the first time, it is determined that the conditions for starting the turn have been met. A work machine characterized by the following features.

5. In the work machine described in claim 2, The aforementioned operation completion angle is the angle at which the working device completes the operation of releasing the excavated material from the bucket above the vessel. The control device determines that the conditions for starting the rotation have been met if, at the moment the rotation start command is output, it is predicted that the rotation of the rotating body will begin before the angle of the bucket relative to the ground reaches the rotation completion angle, and that the bucket will begin to move out of the vessel after the angle of the bucket relative to the ground reaches the rotation completion angle. A work machine characterized by the following features.

6. In the work machine described in claim 5, The control device is The first time from when the rotation start command is output until the rotation of the rotating body begins is calculated. The second time from the current point in time until the angle of the bucket relative to the ground reaches the angle at which the operation is completed is calculated. The third time is calculated from the start of the movement of the rotating body until the bucket begins to exit the vessel. The turning start condition is determined to be met when the second time becomes shorter than the sum of the first time and the third time. A work machine characterized by the following features.

7. In the work machine described in claim 1, The control device determines that the condition for starting the swing has been met when the weight of the excavated material in the bucket reaches a predetermined weight. A work machine characterized by the following features.

8. In the work machine described in claim 1, The control device is The weight of the excavated material in the bucket is obtained, When the weight of the excavated material in the bucket reaches a predetermined weight, it is determined that the conditions for starting the swing have been met. A work machine characterized by the following features.

9. In the work machine described in claim 7, The control device is When the rotational movement of the rotating body has stopped and the work device is operating to excavate the excavated material, it is determined whether or not the rotation start condition has been met. When the weight of the excavated material in the bucket increases to the predetermined weight, it is determined that the conditions for starting the swing have been met. A work machine characterized by the following features.

10. In the work machine described in claim 7, The control device is When the rotational movement of the rotating body has stopped and the work device is operating to discharge the excavated material, it is determined whether or not the rotation start condition has been met. When the weight of the excavated material in the bucket decreases to the predetermined weight by releasing a predetermined percentage of its weight from before the release operation, it is determined that the conditions for starting the rotation have been met. A work machine characterized by the following features.

11. In the work machine according to claim 10, The system includes an input device capable of inputting the predetermined percentage, The control device is The system has a data table that defines the relationship between the ratio of the weight of the excavated material released from the bucket to the weight of the excavated material before it is released from the bucket, and the angle of the bucket relative to the ground. Referencing the data table, determine the ground angle of the bucket corresponding to the predetermined percentage input by the input device as the ground angle threshold. When the angle of the bucket relative to the ground reaches the ground angle threshold, it is determined that the condition for starting the swing has been met. A work machine characterized by the following features.

12. In the work machine according to claim 11, The input device is capable of inputting the soil type of the excavated material. The control device corrects the data table based on the soil type of the excavated material input by the input device. A work machine characterized by the following features.

13. In the work machine according to claim 10, The aforementioned vessel position detection device is an object detection device that detects objects, The control device determines whether the rotation start condition has been met based on the behavior of the excavated material in the bucket detected by the object detection device, or the shape of the excavated material released into the vessel detected by the object detection device. A work machine characterized by the following features.

14. In the work machine described in claim 1, It is equipped with a rotation start operation device operated by an operator, which instructs the start of rotation of the rotating body, The control device is When the rotational movement of the rotating body has stopped and the working device is operating, it is determined whether or not the rotation start condition has been met. When the rotation initiation control device instructs the rotation of the rotating body to begin, it is determined that the rotation initiation condition has been met. A work machine characterized by the following features.

15. In the work machine according to claim 14, It is equipped with a work operation device that is operated by an operator to operate the work device, The control device is When the rotational movement of the rotating body has stopped and the work device is operating in response to the operation of the work device, it is determined whether or not the rotation start condition has been met. When the rotation initiation control device instructs the rotation of the rotating body to begin, it is determined that the rotation initiation condition has been met. A work machine characterized by the following features.

16. In the work machine described in claim 6, The control device is The release time, which is the time from the start time to the completion time of the operation to release the excavated material in the bucket, is calculated. The second time is calculated by subtracting the elapsed time from the start time of the operation to release the excavated material in the bucket from the release time. A work machine characterized by the following features.

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