Work machine

Abstract

This work machine comprises: a traveling body; a turning body; a work device; a posture detection device for detecting the posture of the turning body and the work device; a vessel position detection device for detecting the position of a vessel of a loading machine into which excavation material excavated by the work device is loaded; and a control device for performing automatic turning control for automatically turning at least the turning body up to a turning completion angle on the basis of detection results from the posture detection device and the vessel position detection device. The control device determines whether a turning start condition for starting the automatic turning control is satisfied, on the basis of the turning operation state of the turning body and the operation state of the work device. When it is determined that the turning start condition is satisfied, the control device outputs a turning operation start command for starting the turning of the turning body toward the turning completion angle regardless of whether the work device is in operation.

Description

Work machinery

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

[0002] There are known working machines such as hydraulic excavators that include 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 has 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 materials such as soil and sand, a transport operation to transport the excavated materials to above the bed of a loading machine such as a dump truck, a discharge operation to release the excavated materials onto the bed of the loading machine, and a return operation to move the working equipment to the excavation position.

[0004] Patent Document 1 discloses a control device and control method for a work machine (loading machine) that automatically performs a return operation. Patent Document 1 states, "The control device for a loading machine is a control device for a loading machine that includes a rotating body that rotates about a rotation center and a work machine that has a bucket and is attached to the rotating body, and includes: a loading object specifying unit that specifies the position and shape of the loading object, an avoidance position specifying unit that specifies an interference avoidance position that is a position a predetermined distance outside the loading object based on the position and shape of the loading object, 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 a loading position on the loading object to move the bucket to the interference avoidance position, and after the bucket reaches the interference avoidance position, outputs an operation signal to drive the rotating body and the work machine to move the bucket to an excavation position on an excavation object."

[0005] Japanese Patent Application Laid-Open No. 2020-41352

[0006] Patent Document 1 states that "When automatic excavation and loading control is continuously executed, the empty-load swing 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 swing of the swing unit 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, with the technology described in Patent Document 1, the swing unit remains stopped while the bucket is rotated to dump soil onto the loaded machine. Therefore, in order to perform the return operation, it is necessary to output a swing operation command to rotate the swing unit after the soil discharge is completed.

[0007] However, since it takes time for the rotating body to actually start moving after the rotation command is output, the technology described in Patent Document 1 may result in a decrease in productivity (work efficiency) due to a difference between the timing at which the soil release operation is completed and the timing at which the rotation actually starts.

[0008] The present invention aims to improve productivity by smoothly transitioning from a state in which the work implement is operating alone (for example, a state in which an excavation operation or a discharge operation is being performed) to an operation that requires a rotation operation (for example, a transport operation or a return operation).

[0009] a control device that performs automatic swing control to automatically swing the rotating body at least to a swing completion angle that is a target swing angle based on detection results from the attitude detection device and the vessel position detection device. The control device determines whether a swing start condition for starting the automatic swing control of the rotating body is satisfied based on the swing operation state of the rotating body and the operation state of the work device, and if it determines that the swing start condition is satisfied, outputs a swing operation start command to start swinging the rotating body toward the swing completion angle at the timing when the swing start condition is satisfied, regardless of whether the work device is operating.

[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.

[0011] FIG. 1 is a side view of a hydraulic excavator 1 according to the first embodiment. FIG. 2 is a diagram showing the hydraulic excavator 1 and a loaded machine 200. FIG. 3 is a schematic configuration diagram of a hydraulic drive system 50 of the hydraulic excavator 1. FIG. 4 is a functional block diagram of a control device 40 according to the first embodiment. FIG. 5 is a diagram showing an excavator reference coordinate system as viewed from the Y-axis direction. FIG. 6 is a diagram showing an excavator reference coordinate system as viewed from the Z-axis direction. FIG. 7 is an explanatory diagram of an excavation operation. FIG. 8 is an explanatory diagram of a transport operation and an earth-discharging operation. FIG. 9 is an explanatory diagram of a return operation. 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 earth-discharging operation to the completion of the return operation. FIG. 12 is a diagram showing time-series changes in the ground angle γ of the bucket 10, whether a swing command is output (ON / OFF), and the swing 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. FIG. 13 is a schematic plan view showing a state in which the hydraulic excavator 1 according to Modification 1 of the first embodiment transitions from a dumping operation to a return operation. FIG. 14 is a flowchart showing an example of processing by the control device 40 according to Modification 1 of the first embodiment, showing the flow of processing from the start of the dumping operation to the completion of the return operation. FIG. 15 is a diagram showing a data table for a third time t3r. FIG. 16 is a diagram showing time-series changes in the ground angle γ of the bucket 10, whether a swing command is output (ON / OFF), and the swing angle θsw when an operation transitions from a dumping operation to a return operation in Modification 1 of the first embodiment. FIG. 17 is a functional block diagram of a control device 240 according to the second embodiment. Fig. 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 the excavation operation to the completion of the transport operation. Fig. 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 the soil release operation to the completion of the return operation.FIG. 20 is a diagram showing time series changes in the weight (excavation amount) W of the transported material in the bucket 10, whether a swing command is output (ON / OFF), and the swing angle θsw when the operation transitions from an excavation operation to a transport operation. FIG. 21 is a diagram showing time series changes in the reduction rate Pd of the transported material in the bucket 10, whether a swing command is output (ON / OFF), and the swing angle θsw when the operation transitions from a dumping operation to a return operation. FIG. 22 is a diagram showing the relationship between the reduction rate Pd of the transported material and the ground angle γ of the bucket 10. FIG. 23 is a diagram showing corrected ground angle conversion tables Tc1 and Tc2. FIG. 24 is a functional block diagram of the control device 340 according to the third embodiment. FIG. 25 is a flowchart showing an example of processing by the control device 340 according to the third embodiment, illustrating the flow of processing from the start of the excavation operation to the completion of the transport operation. FIG. 26 is a flowchart showing an example of processing by the control device 340 according to the third embodiment, illustrating the flow of processing from the start of the dumping operation to the completion of the return operation.

[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 multiple identical components, a lowercase letter may be added to the end of the reference numeral. In addition, the multiple components may be collectively referred to without the lowercase letter. For example, when there are two identical traveling hydraulic motors 4a, 4b, these may be collectively referred to 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 excavation work to excavate a surface to be excavated, such as the ground, and loading work to load 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 earth 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 moved in the dump direction to discharge the excavated material onto the loading platform (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 where the next excavation operation will be performed. 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 that is rotatable relative 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 that drives the right crawler and the traveling hydraulic motor 4b that drives the left crawler are collectively referred to as traveling hydraulic motors 4.

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

[0017] The boom 8 has its base end rotatably connected to the front of the rotating body 7 by a boom pin 8a (see FIG. 5). The arm 9 has its base end 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 rotatable relative to one another in the same plane.

[0018] The boom 8 rotates up and down by the extension and retraction of the boom cylinder 11. The arm 9 rotates forward and backward (dumping direction and crowding direction) by the extension and retraction of the arm cylinder 12. The bucket 10 rotates forward and backward (dumping direction and crowding direction) by the extension and retraction 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 as a prime mover mounted on the rotating body 7, and a main pump 102 and a pilot pump 104 as 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 electromagnetic proportional valves 51 that output operating pressures as operating signals to the flow control valve 101, a control device 40 that outputs control signals to the electromagnetic proportional valves 51, operation devices 20 and 21 that are operated by an operator and output signals corresponding 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 according to the operator's operation. The operation devices 20 and 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 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 work operation devices 29. The travel operation device 21 includes a travel operation right lever 23a for operating the right crawler, and a travel 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 operation levers 22, and the travel operation right lever 23a and the travel operation left lever 23b are collectively referred to as operation levers 23.

[0022] The control selection switch 24 is provided on any of the operation levers 22a, 22b, 23a, and 23b. The control selection switch 24 may be configured as a touch sensor on 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 accordance with the operation of the operation device 20, and an automatic mode in which the operation of the hydraulic excavator 1 is controlled in accordance with 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 representing 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 electromagnetic proportional valve 51, and an operating pressure is output from the electromagnetic 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) performed by the left work operation lever 22b, an operation amount sensor 52b that detects the swing operation amount (right swing operation amount and left swing operation amount) performed by the left work operation lever 22b, an operation amount sensor 52c that detects the boom operation amount (boom raising operation amount and boom lowering operation amount) performed by the right work operation lever 22a, an operation amount sensor 52d that detects the bucket operation amount (bucket crowding operation amount and bucket dump operation amount) performed by the right work operation lever 22a, an operation amount sensor 52e that detects the right crawler advance operation amount and right crawler retract operation amount performed by the right travel operation lever 23a, and an operation amount sensor 52f that detects the left crawler advance operation amount and left crawler retract operation amount performed by the left travel operation lever 23b. The arm operation amount, boom operation amount, and bucket operation amount are also collectively referred to as work operation amount.

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

[0026] The control device 40 according to this embodiment controls the rotational movement of the work device 2, the traveling movement of the traveling body 5, and the rotational movement of the rotating body 7 in accordance with the 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 to each solenoid proportional valve 51 (51a to 51l) in accordance with the amount and direction of operation of the control levers 22, 23 by the operator. The solenoid proportional valve 51 is provided in a pilot line 100 to which pressure oil is supplied from a pilot pump 104. The solenoid proportional valve 51 operates when a control signal from the control device 40 is input, and outputs a secondary pressure generated by reducing the primary pressure of the pilot line 100 to a flow control valve 101 as an operating pressure. The flow control valve 101 has multiple spool valves provided for each of the multiple 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 valve 51 is guided to the pressure-receiving chamber of the spool valve, causing the spool to operate. As a result, hydraulic oil discharged from the main pump 102 is supplied to the corresponding hydraulic actuator through the spool valve, thereby operating the hydraulic actuator.

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

[0029] The boom cylinder 11, arm cylinder 12, and bucket cylinder 13 each extend and retract using the supplied pressure oil, rotating the boom 8, arm 9, and bucket 10, respectively. This changes the position of the bucket 10 and the attitude of the work implement 2. The swing hydraulic motor 6 rotates using the supplied pressure oil, rotating the swing unit 7. The travel hydraulic motors 4a and 4b rotate using the supplied pressure oil, causing the travel unit 5 to travel. Note that even when the operator has not operated the operation levers 22 and 23, the hydraulic actuators (4a, 4b, 6, 11, 12, 13) can be driven by operating the electromagnetic proportional valves 51a to 51l using a control signal from the control device 40, which then operates the flow control valve 101.

[0030] The hydraulic excavator 1 is equipped with an attitude detection device 53 that detects the attitude of the vehicle body 3 (swinging unit 7) and the attitude of the working implement 2, including the ground angle of the bucket 10. The attitude detection device 53 is configured to include a plurality of attitude sensors, namely, 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. The boom angle sensor 14 is attached to the boom pin 8a and detects the rotation angle of the boom 8 relative to the swinging unit 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 and 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 and 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 obtains the rotation angles of the boom 8, arm 9, and bucket 10 using the angle sensors 14, 15, and 17.

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

[0032] The tilt angle sensor 18 is attached to the rotating unit 7, detects the tilt 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, arm 9, and bucket 10 are parameters that represent the attitude of the work implement 2. In other words, the boom angle sensor 14, arm angle sensor 15, and bucket angle sensor 17 function as attitude sensors that detect the attitude of the work implement 2. In addition, the tilt angle of the revolving unit 7 and the swing angle of the revolving unit 7 relative to the running unit 5 are parameters that represent the attitude of the revolving unit 7 (vehicle body 3). In other words, the tilt angle sensor 18 and swing angle sensor 19 function as attitude sensors that detect the attitude of the revolving unit 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 light detection and ranging (LiDAR) or a stereo camera, and is attached to the top of the operator's cab 71 or the like (see FIG. 1 ).

[0035] The object detection device 54 detects, for example, the loading platform 201 of the loading machine 200 onto which the excavated 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 functions 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 topography 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 provided 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 in, for example, a hydraulic oil tank or 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 one another 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 from which the programs that realize the functions of this embodiment can be read. The processing device is an arithmetic device that loads the programs stored in the ROM into the RAM and executes the programs, and performs predetermined arithmetic processing 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 (such as the operation detection device 56, the attitude detection device 53, the object detection device 54, the hydraulic oil temperature sensor 55, the control selection switch 24, and the input device 57) 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 (such as the electromagnetic proportional valve 51).

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

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

[0042] When the excavation operation and the soil discharge operation are performed automatically, the control device 40 automatically operates the work device 2 from the operation start attitude to the operation completion attitude based on the detection results of the attitude 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 attitude detection device 53 and the object detection device 54, and automatically operates the work device 2 from the operation start attitude to the operation completion attitude.

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

[0044] The ROM of the control device 40 pre-stores an excavator-reference coordinate system used to identify the positions and postures 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. As shown in FIGS. 5 and 6 , 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. In the excavator-reference coordinate system of this embodiment, the forward movement 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, with the positive direction of the Y-axis being the leftward direction of the traveling body 5. As described above, 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 swing angle θsw of the rotating unit 7 is 0 degrees when the hydraulic excavator 1 is in the reference posture, that is, when the working device 2 is parallel to the X-axis. When the swing angle θsw of the rotating unit 7 is 0 degrees, the operating plane of the working device 2 is parallel to the XZ plane, the direction of the lifting operation 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 attitude calculation unit 41 calculates the attitudes of the components of the hydraulic excavator 1 in the excavator reference coordinate system from the detection signal of the attitude detection device 53. Specifically, the attitude calculation unit 41 calculates a rotation angle θbm of the boom 8 with respect to the X-axis (hereinafter also referred to as the boom angle) from a detection signal of the rotation angle of the boom 8 output from the boom angle sensor 14. The attitude calculation unit 41 calculates a rotation angle θam of the arm 9 with respect to the boom 8 (hereinafter also referred to as the arm angle) from a detection signal of the rotation angle of the arm 9 output from the arm angle sensor 15. The attitude calculation unit 41 calculates a rotation angle θbk of the bucket 10 with respect to the arm 9 (hereinafter also referred to as the bucket angle) from a detection signal of the rotation angle of the bucket 10 output from the bucket angle sensor 17. The attitude calculation unit 41 calculates a swing angle θsw of the swing unit 7 with respect to the X-axis (traveling unit 5) from a detection signal of the swing angle of the swing unit 7 output from the swing angle sensor 19.

[0047] The posture calculation unit 41 calculates the positions of the boom 8, arm 9, and bucket 10 in the excavator reference coordinate system, i.e., the planar positions specified by the X and Y coordinates 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 swing angle θsw of the swing body 7, as well as the boom length Lbm, arm length Lam, and 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 (toe) of the bucket 10. The boom pin 8a is located at a position offset by Lox in the X-axis direction from the swing center axis (Z-axis) when the swing angle is set to 0 degrees.

[0048] Furthermore, although not shown, an 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 a 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 the rotation angles θbm, θam, and θbk of the work implement 2. The ground angle γ of the bucket 10 is the angle formed by a line SL passing through the tip of the bucket 10 and the bucket pin 10a 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 is facing upward and the 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 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 excavator 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 excavator 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 uses the object detection device 54 to acquire the relative position of the platform 201 with respect to the hydraulic excavator 1 (the X, Y, and Z coordinates in the excavator reference coordinate system).

[0050] The position information of the loading platform 201 acquired by the control device 40 is, for example, the position coordinates of the four corners of the top surface of the loading 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 loading platform 201. In other words, it can be said that the position information of the loading platform 201 acquired by the control device 40 includes information on the relative position and relative angle of the loading platform 201 with respect to the revolving unit 7. In other words, in this embodiment, the control device 40 uses the object detection device 54 to acquire, as relative position information, various pieces of information regarding the relative position of the loading platform 201 of the loaded machine 200, onto which the material excavated by the working device 2 is loaded, relative to the working device 2.

[0051] In addition, the object position calculation unit 42 calculates the position information of characteristic points (for example, the abrupt slope, the bottom slope, etc.) of the shape of the terrain 210 to be excavated, in the same way as calculating the position information of the loading platform 201.

[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 returning work by the hydraulic excavator 1, and the target speeds 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 the target speeds of each hydraulic actuator on the target route. The transportation control unit 45 calculates a target route for moving the bucket 10, which stores the excavated material (transported material), onto the platform 201 of the loaded machine 200, and the target speeds 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 the target speeds 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 for 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, transport control unit 45, soil release control unit 46, and 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 of the work implement 2 (for example, the tip of the bucket 10). The operation control unit 400 also calculates a target value γt for 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 for each hydraulic actuator for causing the actual ground angle γ of the bucket 10 to follow the target value γt.

[0054] The excavation operation, transport operation, soil dumping operation, and return operation during automatic operation will be described with reference to Figures 7 to 9. Figure 7 is an explanatory diagram of the excavation operation. As shown in Figure 7, the excavation control unit 44 generates an excavation start position DP1, an excavation completion position DP2, and a target route DPT for the excavation operation, which is a route connecting the excavation start position DP1 and the excavation completion position DP2. The excavation control unit 44 also sets a target value γt for the ground angle of the bucket 10 on the target route DPT. In this way, the excavation control unit 44 sets target values ​​for both the position and angle of the bucket 10 to move a control point, such as the tip of the bucket 10, along the target route 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 for 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 the swing angle θsw and the attitude of the work device 2. The swing angle θsw at the transport start position CP1 is the angle at which the swing for the transport operation starts, and will hereinafter also be referred to as the swing start angle for the transport operation. The swing angle θsw at the transport completion position CP2 is the angle at which the swing for the transport operation completes, and will hereinafter also be referred to as the swing completion angle for the transport operation. The soil-releasing control unit 46 also generates a soil-releasing start position LP1, a soil-releasing completion position LP2, and a target path LPT for 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 for the return movement, 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 defined by the swing angle θsw and the posture of the working implement 2. The swing angle θsw at the return start position RP1 is the angle at which the swing for the return movement starts, and will hereinafter also be referred to as the swing start angle of the return movement. Furthermore, the swing angle θsw at the return completion position RP2 is the angle at which the swing for the return movement completes, and will hereinafter also be referred to as the swing completion angle of the return movement.

[0057] The transport control unit 45, the 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 in order to move the tip of the bucket 10 along the target paths CPT, LPT, RPT.

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

[0059] The operation transition determination unit 49 determines whether each operation transition condition from the excavation operation to the transport operation, from the transport operation to the dumping operation, from the dumping operation to the return operation, and from the return operation to the excavation operation is met. If the operation transition condition is met, the operation transition determination unit 49 generates a start command to start the next operation. The operation transition condition is met when the tip of the bucket 10 has reached the completion position of the target path, and is not met 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 judges that the operation transition condition from the excavation operation to the transport operation has been met, and outputs a command to start the transport operation to the transport control unit 45.

[0061] Furthermore, 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 be sent to the electromagnetic proportional valve 51 according to the calculated target speed, and outputs a control current corresponding to the calculation result to the electromagnetic proportional valve 51. In other words, the actuator command unit 48 outputs a control signal 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 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 in accordance with the target speed calculated by the operation control unit 400, and outputs a control current in accordance with 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 51 a, 51 b 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 unit 7 when the swing operation of the swing unit 7 is stopped is referred to as a "swing operation start command."

[0064] Generally, it takes about 0.1 to 1 second from the time 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, while 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 met, thereby causing the swing body 7 to swing immediately after the excavation operation is completed. Similarly, while 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 met, thereby causing the swing body 7 to swing immediately after the earth-discharging operation is completed.

[0065] The swing start determination unit 43 determines whether to output a swing operation start command for executing an operation that requires swing (transport operation and return operation) without waiting for the completion of the previous work (digging operation and earth 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 work implement 2 is completed. The excavation operation completion angle γ1c is the completion angle of the operation of the work implement 2 to excavate the excavation target. The posture of the work implement 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 work implement 2 is completed. The earth-discharging operation completion angle γ1r is the completion angle of the operation of the work implement 2 to discharge the excavated material in the bucket 10 above the loading platform 201. The posture of the work implement 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 swing start determination unit 43 determines whether a swing start condition for starting automatic swing control of the swing unit 7 is met when the swing operation of the swing unit 7 has stopped and the work implement 2 is operating. The swing start condition is met when it is predicted that, if a swing operation start command is output at the current time, swing of the swing unit 7 will start after the ground angle γ of the bucket 10 reaches the operation completion angle γ1.

[0068] The swing 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 swing operation start command is output when the working device 2 is in that posture, the swing of the swing unit 7 will actually start immediately after the working device 2 reaches the operation completion posture.

[0069] Specifically, as will be described below, the determination of whether the swing start condition is met is made 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 the output of a swing operation start command to the actual start of operation of the swing body 7. Hereinafter, the first time t1 when an excavation operation is being performed will be referred to as a first time t1c, and the first time t1 when an earth-discharging operation is being performed will be referred to as a first time t1r.

[0070] The first time t1 may be obtained by 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 measured 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 drive torque, with the swing unit 7 and the three driven members (boom 8, arm 9, and bucket 10) that make up the work implement 2 treated as rigid bodies. The drive 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 used 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. Furthermore, 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 for the first time t1 that corresponds to the attitude of the work device 2 (boom angle, arm angle, bucket angle) and the temperature of the hydraulic oil. The characteristic data for the first time t1 may be a data table for the first time t1 that changes depending on the attitude of the work device 2 and the temperature of the hydraulic oil, or may be function data. Note that the characteristic data for the first time t1c and the characteristic data for the first time t1r may be the same or different. The swing start determination unit 43 references the characteristic data for the first time t1 and calculates the first time t1 based on the attitude of the work device 2 calculated by the attitude 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 work implement 2 assumes the operation completion posture. Note that 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 will be referred to as a second time t2c, and the second time t2 when an earth-discharging operation is being performed will be referred to as a second time t2r.

[0074] The second time t2c corresponds to the 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 the 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 earth-discharging control unit 46, and the target speed of each hydraulic actuator up to the earth-discharging operation completion attitude.

[0076] The second time t2 is not limited to being calculated by the rotation start determination unit 43. The excavation control unit 44 or the soil release control unit 46 may calculate the second time t2 and output the calculated second time t2 to the rotation 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 turning start judgment unit 43 judges that the turning start condition is met and sets a turning flag indicating the judgment result to on.

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

[0079] In this way, the swing start determination unit 43 determines that the swing start condition is met when the second time t2 becomes shorter than the first time t1 due to the work implement 2 being operated, such as an excavation operation or an earth dumping operation. In other words, the swing start determination unit 43 determines whether the swing start condition is met based on the operating state of the work implement 2. Furthermore, the swing start condition is based on the premise that the swing operation has stopped. For this reason, the swing start determination unit 43 determines whether the swing start condition is met based not only on the operating state of the work implement 2 but also on the swing operation state of the revolving 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 rotating body 7 during the transport operation while continuing the excavation operation. As a result, a swing operation start command for starting the movement of the rotating 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 electromagnetic 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 rotating body 7 during the return operation while continuing the earth-discharging operation. As a result, a swing operation start command for starting the movement of the rotating 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 electromagnetic 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 Figures 10 and 11. Figure 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. Figure 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 Figures 10 and 11, an example will be described in which only one excavation operation, one transport operation, one soil-releasing operation, and one return operation are performed. However, a series of these operations may be performed multiple times. Furthermore, it is not necessarily necessary to start with the excavation operation.

[0082] 10 , in step S101, when control selector switch 24 is operated to change the control mode to automatic mode, operation transition determination unit 49 sets the control mode to automatic mode. When automatic mode is set, actuator command unit 48 starts an excavation operation by working 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 excavation control, excavation control unit 44 automatically operates working implement 2 until ground angle γ of bucket 10 becomes excavation operation completion angle γ1c.

[0083] In the next step S102, the swing start determination unit 43 calculates the time (first time) t1c from the output of the swing operation start command for the transport operation until the swing body 7 starts moving. In the next step S103, the swing start determination unit 43 calculates the time (second time) t2c from the current time until 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 be started after the work implement 2 reaches the excavation operation completion posture if a swing operation start command is currently output. In other words, the processing of step S104 is processing for determining whether or not the swing start condition is met.

[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 transport turning flag to ON, and proceeds to step S105.

[0086] In step S105, the transport control unit 45 starts controlling the rotating unit 7 in the transport operation. That is, in step S105, the transport control unit 45 outputs a swing operation start command for the transport operation. In the next step S106, the operation transition determination unit 49 determines whether 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 processing of step S106 is repeatedly executed at a predetermined calculation cycle until a positive determination is made.

[0087] In step S107, the transportation control unit 45 starts control of the working device 2 during the transportation operation. As described above, the control of the revolving unit 7 during 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 met, the transport operation is completed. When the transport operation is completed, the transport control unit 45 sets the transport swing flag to OFF. When the transport operation is completed, the processing 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 implement 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 time when the swing unit 7 starts moving after the return swing command is issued. 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 soil discharge 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 movement of the swing body 7 in the predetermined direction will be started after the work implement 2 reaches the soil-release operation completion posture if a swing operation start command is currently output. In other words, the processing of step S113 is processing for determining whether or not the swing start condition is met.

[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 swing unit 7 during 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 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 processing of step S115 is repeatedly executed at a predetermined calculation cycle until a positive determination is made.

[0093] In step S116, the return control unit 47 starts control of the working device 2 during the return operation. As described above, the control of the revolving unit 7 during the return operation is started before the operation transition condition is met (step S114).

[0094] In the next step S108, the return operation is completed when the tip of the bucket 10 reaches the return completion position RP2. 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 processing shown in the flowchart in FIG. 11 ends.

[0095] The main operations of the hydraulic excavator 1 according to this embodiment will be described below 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, whether a swing command is output (ON / OFF), and the swing angle θsw when an operation transitions from an excavation operation to a transport operation or from a dumping operation to a return operation. The horizontal axes in FIGS. 12( a) to 12(c) represent time. The vertical axis in FIG. 12(a) represents the ground angle γ of the bucket 10, the vertical axis in FIG. 12(b) represents whether a swing command is output, and the vertical axis in FIG. 12(c) represents the swing angle θsw. Note that the swing angle θsw is plotted as a graph that increases in a positive direction from the reference position where the excavation operation or the dumping operation starts to the operation completion angle, with the reference position being set as the reference position. For ease of explanation, FIG. 12 also shows the time-series changes in each parameter when the excavation operation transitions to a transport operation and when the dumping operation transitions to a return operation using a common graph. However, the time series changes of the parameters during the transition from the excavation operation to the transport operation and 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 using Figures 7 and 12. The control device 40 determines whether the swing start condition is met when the swing operation of the swing unit 7 has stopped and the work implement 2 is operating automatically so that the ground angle γ of the bucket 10 approaches the excavation operation completion angle γ1c (steps S101 to S104 in Figure 10).

[0097] At time T2, a certain time after the start of the excavation operation in state S10, when the swing start condition is met (Yes in step S104 in FIG. 10 ), automatic swing control of the rotating unit 7 is initiated (state S11). On the other hand, at time T1, which is before time T2, the swing start condition is not met (No in step S104 in FIG. 10 ), and therefore automatic swing control of the rotating unit 7 is not initiated. Automatic swing control of the rotating unit 7 is initiated (a swing 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 swing operation start command to start swinging the rotating unit 7 toward the swing completion angle at the timing (time T2) when the swing start condition is met. As a result, the rotating unit 7 actually begins to swing immediately after the ground angle γ of the bucket 10 reaches the operation completion angle γ1 (the excavation operation completion angle γ1c) (state S12). 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 for a smooth transition from the excavation operation to the transport operation.

[0098] The excavation control unit 44 sets the excavation completion position DP2 to a position where there is no earth or sand around the bucket 10, based on the information on the excavation target topography 61 acquired by the object detection device 54. Therefore, even if the swing operation is started immediately after the excavation completion position DP2 is reached, there is no earth or sand that will strike the bucket 10 sideways, and therefore 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 begins for the work implement 2. The rotating body 7 and the work implement 2 perform the transport operation, and when the tip of the bucket 10 reaches the transport completion position CP2 (see FIG. 8), the transport operation is completed.

[0100] 9 and 12, the operation when transitioning from the earth-discharging operation to the return operation will be described. The control device 40 determines whether the swing start condition is met when the swing operation of the swing unit 7 has stopped and the work implement 2 is operating automatically so that the ground angle γ of the bucket 10 approaches the earth-discharging operation completion angle γ1r (steps S109 to S113 in FIG. 11).

[0101] When the swing start condition is satisfied at time T2, a certain time after the start of the soil-discharging operation in state S20 (Yes in step S113 in FIG. 11 ), automatic swing control of the rotating unit 7 is started. On the other hand, at time T1, which is before time T2, the swing start condition is not satisfied (No in step S113 in FIG. 11 ), and therefore automatic swing control of the rotating unit 7 is not started. Automatic swing control of the rotating unit 7 is started (a swing operation start command is output) at a stage (time T2) before time T3, when the soil-discharging operation is completed. In this way, the control device 40 outputs a swing operation start command to start swinging the rotating unit 7 toward the swing completion angle at the timing (time T2) when the swing start condition is satisfied. As a result, the rotating unit 7 actually starts swinging immediately after the ground angle γ of the bucket 10 reaches the operation completion angle γ1 (soil-discharging 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 substantially coincides with the timing when the rotating body 7 starts to rotate. 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 soil-discharge operation completion angle γ1r, return control begins for the work implement 2. The revolving unit 7 and work implement 2 perform a return operation, and when the tip of the bucket 10 reaches the return completion position RP2 (state S22), the return operation is completed.

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

[0104] (1) A hydraulic excavator (work machine) 1 includes a traveling body 5, a rotating body 7 rotatably provided relative 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 material excavated by the working device 2 is loaded. The hydraulic excavator 1 also includes a control device 40 that performs automatic swing control to automatically swing at least the rotating body 7 to a swing completion angle, which is a target swing angle, based on the detection results of the attitude detection device 53 and the object detection device 54. The swing start angle, which is the swing angle at which automatic swing control is started, is the swing angle θsw at the transport start position CP1 in the case of a transport operation, and is the swing angle θsw at the return start position RP1 in the case of a return operation. The swing completion angle, which is the swing angle at which automatic swing control is completed, is the swing angle θsw at the transport completion position CP2 in the case of a transport operation, and is the swing angle θsw at the return completion position RP2 in the case of a return operation. The control device 40 determines whether a swing start condition for starting automatic swing control of the swing unit 7 is met, based on the swing operation state of the swing unit 7 and the operation state of the work device 2. If the control device 40 determines that the swing start condition is met, it outputs a swing operation start command to start swinging the swing unit 7 toward the swing completion angle at the timing when the swing start condition is met, regardless of whether the work device 2 is in an operating state.

[0105] When a swing start condition is satisfied during an excavation operation, the control device 40 outputs a swing operation start command to start transport control of the swing unit 7. As a result, the swing unit 7 actually starts to swing simultaneously with or immediately after the work device 2 reaches the excavation operation completion posture. Therefore, according to this embodiment, a smooth transition from an excavation operation to a transport operation can be achieved. Furthermore, when a swing start condition is satisfied during an earth-discharging operation, the control device 40 outputs a swing operation start command to start return control of the swing unit 7. As a result, the swing unit 7 actually starts to swing simultaneously with or immediately after the work device 2 reaches the earth-discharging operation completion posture. Therefore, according to this embodiment, a smooth transition from an earth-discharging operation to a return operation can be achieved. In other words, according to this embodiment, during an excavation and loading operation, a smooth transition can be achieved from a state in which the work device 2 is operating independently to an operation that requires a swing operation. As a result, 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 results of the attitude detection device 53. The control device 40 automatically operates the work implement 2 during each of the excavation operation and the earth-discharging operation until the ground angle γ of the bucket 10 reaches the operation completion angle γ1. The control device 40 determines whether the swing start condition is met when the swing operation of the swing unit 7 stops 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 enables smooth transitions from the automatic excavation operation to the automatic transport operation, and from the automatic earth-discharging operation to the automatic return operation.

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

[0108] (4) The control device 40 calculates a first time t1 from the output of a swing operation start command to the start of operation of the rotating unit 7. The control device 40 calculates a 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 swing 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 swing 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 posture of the work implement 2. This more appropriately prevents the rotating unit 7 from actually starting to swing before the ground angle γ of the bucket 10 reaches the operation completion angle γ1.

[0109] <First Modification of First Embodiment> In the first embodiment, an example has been described in which the control content when transitioning from an excavation operation to a transport operation is the same as the control content when transitioning from an earth-releasing operation to a return operation. However, the present invention is not limited to this. Below, a modification of the control content when transitioning from an earth-releasing operation to a return operation will be described with reference to FIGS. 13 to 16 .

[0110] 13 is a schematic plan view showing the hydraulic excavator 1 according to Modification 1 of the first embodiment transitioning from an earth-discharging operation to a 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 rotating body 7 starts after the work device 2 reaches the earth-discharging operation completion posture. In contrast, the control device 40 according to Modification 1 outputs a swing start command during the earth-discharging operation so that the rotation of the rotating body 7 starts before the work device 2 reaches the earth-discharging operation completion posture and so that the bucket 10 begins to move out of the platform 201 after the work device 2 reaches the earth-discharging operation completion posture.

[0111] 13, in this first modification, the work implement 2 continues the earth-discharging operation even while the revolving unit 7 is revolving so that the bucket 10 reaches the rear end of the platform 201 from the return start position RP1. The earth-discharging operation by the work implement 2 is then completed just before the bucket 10 begins to move out of the platform 201. Thereafter, the revolving unit 7 and the work implement 2 are controlled so that the control point of the bucket 10 moves along the target route RPT that connects the position RP3 and the return completion position RP2.

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

[0113] 14 , in this modification, once the calculation process for 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 a 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 platform 201 calculated by the object position calculation unit 42. The third time t3r corresponds to the time from when the rotating unit 7 actually starts to swing until the bucket 10 starts to move out of the platform 201. In other words, the third time t3r corresponds to the time until the rotating unit 7 reaches the rear end of the platform 201.

[0114] The swing start determination unit 43 may calculate the third time t3r using a data table that defines 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 the data table for the third time t3r. The data table for the third time t3r is determined in advance through experiments or the like and stored in a storage device. The swing start determination unit 43 calculates the swing angle θsw1 of the bucket 10 from the current position to the position where it 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 in 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 processing of step S113B is processing to determine whether or not the swing start condition is satisfied. In step S113B, the swing start determination unit 43 compares the sum of the first time t1r and the third time t3r with the second time t2r. Through this comparison, the swing start determination unit 43 determines whether, if a swing operation start command is output at the current time, the swing of the swing unit 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 move out of the loading platform 201 after the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r.

[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 met 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 met, 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 loading 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, whether or not a swing operation command is output (ON / OFF), and the swing angle θsw when the operation transitions from the earth-discharging operation to the return operation in Modified Example 1 of the first embodiment.

[0120] In this modification, at time Tr2, a certain time has elapsed since state S20, in which the earth-discharging operation has started, the swing start condition is met (Yes in step S113B in FIG. 14 ), and automatic swing control of the rotating unit 7 is initiated. On the other hand, at time Tr1, which is before time Tr2, the swing start condition is not met (No in step S113B in FIG. 14 ), and automatic swing control of the rotating unit 7 is not initiated. In this modification, the rotating unit 7 actually starts to swing at time Tr3, which is before time Tr4, when the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r. Therefore, as the rotating unit 7 swings, the bucket 10 moves toward the rear end of the loading platform 201 while performing a dumping operation above the loading platform 201. When the swing angle θsw increases to the predetermined swing angle θsw1, the state S21 is reached in which the bucket 10 has reached the rear end of the loading platform 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 loading platform 201.

[0121] In this modified example, the timing at which the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r coincides with the timing at which the bucket 10 reaches the rear end of the platform 201. At time Tr4, when the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r in state S21, return control of the work implement 2 begins. The revolving unit 7 and work implement 2 perform a return operation, and when the tip of the bucket 10 reaches the return completion position RP2 in state S22, 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 currently outputs a swing start command while the work implement 2 is performing an earth-discharging operation (discharging operation) to discharge the excavated material in the bucket 10 above the loading platform 201, the control device 40 determines that the swing start condition is met if it predicts that the swing of the rotating body 7 will start before the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle (operation completion angle) γ1r and that the bucket 10 will start to move out of the loading platform 201 after the ground angle γ of the bucket 10 reaches the earth-discharging operation completion angle γ1r. The control device 40 determines that the swing start condition is not met until the above prediction is made. In this modified example, the predetermined posture for outputting the swing start command when an earth-discharging operation is being performed is different from that of the above embodiment. The predetermined posture in this modified example is a posture in which, if a swing start command is output while the work implement 2 is in that posture, the work implement 2 will start to move out of the loading platform 201 immediately after the work implement 2 reaches the earth-discharging operation completion posture. In this modified example, the revolving body 7 can actually be moved above the loading platform 201 before the soil-releasing operation is completed, so that productivity can be improved compared to the above embodiment.

[0124] (6) The control device 40 calculates a first time t1r from the output of a swing operation start command to the start of operation of the swing unit 7. The control device 40 calculates a 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 a third time t3r from the start of operation of the swing unit 7 to the time when the bucket 10 begins to move out of the platform 201. The control device 40 determines that the swing start condition is met when the second time t2r is 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 attitude of the work implement 2. This makes it possible to appropriately prevent the swing unit 7 from moving out of the platform 201 before the work implement 2 reaches the earth-discharging operation completion attitude.

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

[0126] <Variation 2-1 of First Embodiment> For example, the control device 40 may calculate the second time t2r using a data table (hereinafter also referred to as the second time characteristics table) that defines 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 properties (viscosity, particle size) of the excavated material. Therefore, the control device 40 may correct the second time characteristics table based on the soil properties of the excavated material. The soil properties of the excavated material are input to the control device 40 by the input device 57. The control device 40 refers to the corrected second time characteristics table and calculates the second time t2r based on the ground angle γ of the bucket 10.

[0127] <Variation 2-2 of First Embodiment> Furthermore, the control device 40 may calculate the time from the start to the completion of the earth-discharging operation (hereinafter referred to as the required discharge time) based on the behavior of the transported material (excavated material) in the bucket 10 during the first earth-discharging operation of the excavation and loading cycle using the object detection device 54, and use this time to control the transition from the second or subsequent earth-discharging operation to the return operation of the excavation and loading cycle. The behavior of the transported material in the bucket 10 may be, for example, a change in the area of ​​the transported material in the bucket 10 in images captured by a stereo camera serving as the object detection device 54. During the first earth-discharging operation of the excavation and loading cycle, the control device 40 determines that the earth-discharging operation is complete and calculates the required discharge 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 at which the soil-releasing operation is completed may be instructed to the control device 40 by the operator operating the input device 57. For example, in the first soil-releasing operation of the excavation and loading cycle, the control device 40 stores the time from the start of the soil-releasing 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 time elapsed from the start time of the soil-releasing operation from the required release time in the second and subsequent excavation and loading cycles.

[0130] In this way, the control device 40 according to this modified example calculates, in the first earth-discharging operation, 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. In 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 swing operation start command can be output from the control device 40 at an appropriate timing, regardless of individual differences in the hydraulic excavator 1 performing the work, etc.

[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 . Components that are the same as or equivalent to those described in the first embodiment are designated by the same reference symbols, and differences will be mainly described. A control device 240 according to the second embodiment acquires the weight of the material being carried in the bucket 10 (excavated material such as earth and sand) and determines whether the swing start condition is met based on the acquired weight. The control device 240 determines that the swing start condition is met when the weight of the material being excavated in the bucket 10 reaches a predetermined weight. The control device 240 determines that the swing start condition is not met when the weight of the material being excavated in the bucket 10 has not reached the predetermined weight. The configuration of the hydraulic excavator 1 according to the second embodiment and the functions of the control device 240 will be described in detail below.

[0132] FIG. 17 is a functional block diagram of a control device 240 according to the second embodiment. The hydraulic excavator 1 according to the second embodiment includes a transported item information acquisition device 258. The transported item information acquisition device 258 calculates the weight of the transported item stored in the bucket 10. The transported item 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 computing device that calculates the weight of the transported item based on the detection results of the pressure sensor and the detection results of the attitude detection device 53. Note that the configuration of the transported item information acquisition device 258 is not limited to this. The transported item information acquisition device 258 may also be a weight sensor that directly detects the weight of the transported item in the bucket 10. Furthermore, in this embodiment, an example is described in which the computing device of the transported item information acquisition device 258 is provided separately from the control device 240, but the functions of the computing device of the transported item information acquisition device 258 may also be provided by 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 the excavation operation to the completion of the 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 the soil release operation to the completion of the 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 Figure 18, excavation control is started in step S101. As a result, the hydraulic excavator 1 stops the swinging operation of the swing body 7 and enters a state in which the work implement 2 is operating to excavate the material to be excavated. In the second embodiment, excavation control is performed so that the weight (excavation volume) W of the material to be excavated 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 material to be stored in the bucket 10, and is determined in advance and stored in a storage device.

[0136] The next step, S201, is a process for determining whether a swing start condition is met. In step S201, the swing start determination unit 43 determines whether the amount of excavated material stored in the bucket 10 is equal to or greater than a predetermined percentage P1 of 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 percentage P1 is determined in advance and stored in the storage device. The predetermined percentage P1 is, for example, a value equal to or greater than 90%. The predetermined percentage P1 may be changeable by operating the input device 57. If it is determined that the amount of excavated material stored in the bucket 10 is equal to or greater than the predetermined percentage P1 of 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 determination 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 predetermined calculation intervals. 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 corresponding to a predetermined ratio P1 of the target excavation amount Wt, and is calculated by the swing start determination unit 43.

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

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

[0140] The next step S202 is a process for determining whether or not a swing start condition is satisfied. In step S202, the swing start determination unit 43 determines whether or not 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, 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 determining whether or not the percentage Pd of the weight W of the transported object decreased with respect to the weight W0 before the dumping operation (hereinafter also referred to as the reduction percentage of the transported object) has reached the predetermined percentage P2 or more.

[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 approximately 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 soil-discharging operation. If it is determined that the weight W of the transported object has decreased by a predetermined percentage P2 or more relative to the weight W0 before the soil-discharging 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 acquires information on the weight W of the transported object from the transported object information acquisition device 258 at predetermined calculation intervals. 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 calculated by the swing start determination unit 43 and is the value obtained by subtracting a weight (W0×P2) corresponding to a predetermined ratio P2 of the released weight, i.e., the weight W0 before the dumping operation, from the weight W0 before the dumping operation (W2=W0−W0×P2).

[0144] The processing of steps S114 to S117 in FIG. 19 is the same as that in the first embodiment (see FIG. 11), and therefore a description thereof will be omitted.

[0145] Below, main operations of the hydraulic excavator 1 according to the second embodiment will be described with reference to FIGS. 20 and 21 . First, operations during a 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 volume) W of the transported material in the bucket 10, whether a swing operation command has been output (ON / OFF), and the swing angle θsw when the operation transitions from excavation operation to transport operation. The horizontal axis in FIGS. 20( a) to 20(c) represents time. The vertical axis in FIG. 20(a) represents the weight (excavation volume) W of the transported material in the bucket 10. The vertical axis in FIG. 20(b) represents whether a swing operation command has been output, and the vertical axis in FIG. 20(c) represents the swing angle θsw. Note that the swing angle θsw is plotted as a graph in which the position at which the excavation operation starts is set as a reference position, and increases in a positive direction from the reference position to the angle at which the excavation operation is completed.

[0146] As shown in FIG. 20 , at time Tc22, a certain time after the start of the excavation operation, the swing start condition is met (Yes in step S201 in FIG. 18 ), and automatic swing control of the rotating unit 7 is initiated. On the other hand, at time Tc21, prior to time Tc22, the swing start condition is not met (No in step S201 in FIG. 18 ), and therefore automatic swing control of the rotating unit 7 is not initiated. Automatic swing control of the rotating unit 7 is initiated (a swing operation start command is output) at a stage (time Tc22) prior to 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 unit 7 actually begins to swing immediately after the weight W of the transported material in the bucket 10 reaches the target excavation volume Wt. In other words, the timing at which the weight W of the transported material in the bucket 10 reaches the target excavation volume Wt and the timing at which the rotating unit 7 begins to swing are approximately the same. This allows for a smooth transition from the excavation operation to the transport operation.

[0147] Next, the operation when transitioning from the dumping operation to the return operation will be described using 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 FIGS. 21( a) to 21(c) represents time. The vertical axis in FIG. 21(a) represents the reduction rate Pd [%] of the transported goods. The vertical axis in FIG. 21(b) represents the presence or absence of a swing operation command, and the vertical axis in FIG. 21(c) represents the swing angle θsw. Note that the swing angle θsw is plotted as a graph that increases in the positive direction from the reference position where the dumping operation starts to the angle at which the dumping operation is completed, with the position at which the dumping operation starts being the reference position.

[0148] As shown in FIG. 21 , at time Tr22, a certain time after the start of the soil dumping operation, the swing start condition is met (Yes in step S202 in FIG. 19 ), and automatic swing control of the rotating unit 7 is initiated. On the other hand, at time Tr21, prior to time Tr22, the swing start condition is not met (No in step S202 in FIG. 19 ), and automatic swing control of the rotating unit 7 is not initiated. Automatic swing control of the rotating unit 7 is initiated (a swing operation start command is output) at a stage (time Tr22) prior to time Tr23, when the transported goods reduction rate Pd reaches 100%. As a result, the rotating unit 7 actually begins to swing immediately after the transported goods reduction rate Pd reaches 100%. In other words, the timing when the transported goods reduction rate Pd reaches 100% and the timing when the rotating unit 7 starts to swing are approximately the same. This allows a smooth transition from the soil dumping operation to the return operation.

[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 met 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 met when the rotation of the rotating unit 7 has stopped and the work implement 2 is operating to excavate the excavated object. The control device 240 determines that the swing start condition is met when the weight W of the excavated object in the bucket 10 has increased 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 met when the rotation of the rotating unit 7 has stopped and the work implement 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 predetermined percentage P2 of the material 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 and S114 in FIG. 19). The second embodiment provides the same effects as the first embodiment.

[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, thereby reducing the calculation load on the control device 240.

[0151] 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 a ground angle (ground angle threshold) γ2 corresponding to a predetermined rate P2, the swing start determination unit 43 may determine that the swing start condition is met and output a swing 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 load and the ground angle γ of the bucket 10. When the swing start determination unit 43 acquires information about 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, which is a data table that defines the relationship between the ratio Pd 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) and the ground angle γ of the bucket 10. The control device 240 references the ground angle conversion table T and determines the ground angle of the bucket 10 that corresponds to the predetermined ratio P2 input via the input device 57 as the ground angle threshold γ2. When the ground angle γ of the bucket 10 reaches the ground angle threshold γ2, the control device 240 determines that the swing start condition is met and outputs a swing operation start command. This configuration allows the operator to adjust the timing of the swing operation by operating the input device 57.

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

[0155] <Variation 2-1 of 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 actual machine data of the hydraulic excavator 1. FIG. 23 shows corrected ground angle conversion tables Tc1 and Tc2. For example, while the earth-discharging 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 earth-discharging operation. This results in, for example, a corrected ground angle conversion table Tc1. The control device 240 refers to the corrected ground angle conversion table Tc1 and calculates a 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 earth-discharging operation, the control device 240 determines that the swing start condition is met 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 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 quality of the transported material. The hydraulic excavator 1 according to this modification is equipped with an input device 57 that can input soil quality 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] If 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 decreases. This results in a corrected ground angle conversion table Tc2. The control device 240 references 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 also 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 location is changed, the control device 240 can output a rotation operation start command at an appropriate timing.

[0160] <Variation 2-3 of Second Embodiment> Furthermore, if the angular velocity of the bucket 10 is high, the reduction rate Pd of the transported load at a certain ground angle γ becomes smaller than expected. Therefore, the swing 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] <Third Modification of Second Embodiment> The control device 240 may calculate a reduction rate Pd of the transported materials in the bucket 10 during the soil-discharging operation (discharging operation) based on the behavior of the transported materials (excavated materials) in the bucket 10 detected by the object detection device 54. The behavior of the transported materials in the bucket 10 may be, for example, a change in the area of ​​the transported materials 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 materials based on the shape of the transported materials (excavated materials) discharged onto the loading platform 201 detected by the object detection device 54. When the transported materials are discharged onto the loading platform 201, a pile of the transported materials is formed on the loading platform 201 corresponding to the amount of the transported materials discharged. Therefore, the control device 240 can estimate the amount of the transported materials discharged from the shape of the transported materials detected by the object detection device 54. When the reduction rate Pd of the transported materials reaches a predetermined rate P2, a swing start condition is satisfied, and the control device 240 outputs a swing operation start command.

[0162] In this way, the control device 240 according to this modification determines whether the swing 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 Figures 24 to 26. Note that components 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 was described in which the excavation operation, transport operation, soil-discharging operation, and returning operation are performed automatically. In contrast, in the third embodiment, an example will be described in which the excavation operation and soil-discharging operation are performed manually, and the transport operation and returning operation are performed automatically.

[0164] Figure 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 the timing instructed by the operator. Furthermore, the hydraulic excavator 1 according to this embodiment is configured to automatically perform a return operation after an earth-discharging operation performed manually by an operator. The control device 340 outputs a command to start a swing operation for the return operation at the timing instructed by the operator.

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

[0166] The operation transition determination unit 349 according to the third embodiment sets the control mode to 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, as in 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 an excavation operation has been performed by the work operation device 29. Furthermore, the operation transition determination unit 349 determines that the operation transition condition from the earth-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 an earth-discharging operation has been performed by the work operation device 29. Note that the operation transition determination unit 349 determines that the work operation device 29 has been returned to the neutral position after an excavation operation or earth-discharging operation has been performed by the work operation device 29 when any of the arm operation amount, boom operation amount, and bucket operation amount detected by the operation amount sensors 52a, 52c, 52d of the operation detection device 56 becomes equal to or greater than the operation determination threshold and then all of the arm operation amount, boom operation amount, and bucket operation amount become equal to or less than the neutral determination threshold.

[0168] The swing start determination unit 343 according to the third embodiment determines whether the current motion state is an excavation motion, a transport motion, an earth dumping motion, or a return motion, based on the determination result of the motion transition determination unit 349. Furthermore, the swing start determination unit 343 determines that a swing operation has been performed when the amount of swing 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 met if a swing operation is performed while an excavation operation is being performed. Also, the swing start determination unit 343 determines that the swing start condition is met if 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 the excavation operation to the completion of the 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 the soil release operation to the completion of the 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 process 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 process of step S115 in the flowchart of Fig. 11.

[0172] 25 , in step S301, when an operation to change the control mode to semi-automatic mode is performed using control selector switch 24, operation transition determination unit 349 sets the control mode to semi-automatic mode. When 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 next step, S302, is a process for determining whether or not a turning start condition is satisfied. In step S302, 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 step S105. The process of step S302 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 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 rotating body 7. In the next step S303, the operation transition determination unit 49 determines whether 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, when 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, when 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 processing of step S303 is repeatedly executed at a predetermined calculation cycle until a positive determination is made.

[0175] The processes in steps S107 and S108 in FIG. 25 are the same as those in the first embodiment (see FIG. 10), and therefore a description thereof will be omitted.

[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 corresponding to the amount of operation of the work operation device 29.

[0177] The next step S305 is similar to the step S302 in that it determines whether or not a turning start condition is met. 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 met, and proceeds to step S114. The 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 step S305 until a turning operation is performed.

[0178] In step S114, the transportation control unit 45 outputs a swing operation start command for the return operation of the swing body 7. In the next step S306, the operation transition determination unit 49 determines whether the operation transition condition from the soil release operation to the return operation is met. If the work operation device 29 has been returned to the neutral position (in this embodiment, when 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 met, and proceeds to step S116. If the work operation device 29 has not been returned to the neutral position (in this embodiment, when 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 met. The processing of step S306 is repeatedly executed at a predetermined calculation cycle until a positive determination is made.

[0179] The processes of steps S116 and S117 in FIG. 26 are the same as those in the first embodiment (see FIG. 11), and therefore a description thereof will be omitted.

[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, which causes 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, which causes 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 complete, 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, causing the work device 2 to perform the earth-releasing operation (step S304). When the earth-releasing 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 the return operation (steps S305, S114, S117).

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

[0184] As described above, the third embodiment includes a swing operation device (swing start operation device) 28 that is operated by the operator to instruct the start of swing of the swing unit 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 accordance with the operation of the work operation device 29. The control device 340 determines whether or not a swing start condition is met when the swing operation of the swing unit 7 has stopped and the work device 2 is operating in accordance with the operation of the work operation device 29. The control device 340 determines that the swing start condition is met when the swing operation device 28 instructs the start of swing of the swing unit 7.

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

[0186] <First Modification of Third Embodiment> The hydraulic excavator 1 according to the third embodiment has been described as being configured to perform the excavation operation and the soil dumping operation based on manual operation by the operator and to automatically perform the transport operation and the returning operation. However, the hydraulic excavator 1 may be configured to perform only the excavation operation based on manual operation by the operator and to automatically perform the transport operation, soil dumping operation, and returning operation. Alternatively, the hydraulic excavator 1 may be configured to perform only the soil dumping operation based on manual operation by the operator and to automatically perform the excavation operation, transport operation, and returning operation. Alternatively, the hydraulic excavator 1 may be configured to automatically perform all of the excavation operation, transport operation, soil dumping operation, and returning operation. In this case, the hydraulic excavator 1 may be configured so that the operator only instructs the timing of outputting a swing operation start command for the transport operation or the returning 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 determines whether or not the swing start condition is met when the swing operation of the swing body 7 has stopped and the work device 2 is operating. The control device 340 determines that the swing start condition is met 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 operator's intention not only during manual operation by the operator but also during an excavation operation or soil discharge operation performed by automatic operation by the control device 340.

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

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

[0191] <Modification 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] <Modification 2> In the above embodiment, a backhoe excavator in which the bucket 10 is 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 also be a loading shovel in which the bucket 10 is attached to the tip of the arm 9 facing forward.

[0193] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate 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 embodiments.

[0194] 1... Hydraulic excavator (work machine), 2... Work 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...Tilt angle sensor (attitude sensor), 19...Swing angle sensor (attitude sensor), 20, 21...Operation device, 24...Control selection switch, 28...Swing operation device (swing start operation device), 29...Work operation device, 40...Control device, 41...Attitude calculation unit, 42...Object position calculation unit, 43...Swing start determination unit, 44...Excavation control unit, 45...Transportation control unit, 46...Soil discharge control unit, 47...Return control unit, 48...Actuator command unit, 49...Operation transition determination unit, 50...Hydraulic drive system, 51...Electromagnetic 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...loaded machine, 201...loading platform (tray, vessel), 240...control device, 258...transported object information acquisition device, 324...control selection switch, 340...control device, 343...swing start determination unit, 349...operation transition determination unit, 400...operation control unit, CP1...transportation start position, CP2...transportation completion position, CPT...target route, DP1...digging start position, DP2...digging 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 earth release operation, W1, W2...predetermined weight, Wt...target excavation amount, γ...ground angle, γ1c...excavation operation completion angle (operation completion angle), γ1r...earth release operation completion angle (operation completion angle), γ2, γc21, γc22...ground angle threshold, γt...target ground angle, θsw...turning angle

Claims

1. A work machine comprising: a traveling body; a rotating body rotatably provided with respect 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 that detects the attitude of the rotating body and the attitude of the working device; a vessel position detection device that detects the position of a vessel of a loading machine into which material excavated by the working device is loaded; and a control device that performs automatic rotation control to automatically rotate the rotating body at least to a rotation completion angle that is a target rotation angle based on detection results of the attitude detection device and the vessel position detection device, wherein the control device determines whether a rotation start condition for starting the automatic rotation control of the rotating body is established based on the rotation operation state of the rotating body and the operation state of the working device, and when it is determined that the rotation start condition is established, outputs a rotation operation start command to start rotating the rotating body towards the rotation completion angle at the timing when the rotation start condition is established, regardless of whether the working device is in an operating state or not.

2. A work machine as described in claim 1, wherein the control device calculates the ground angle of the bucket based on the detection result of the attitude detection device, automatically operates the work device until the ground angle of the bucket becomes the operation completion angle, and determines whether the rotation start condition is satisfied when the rotation of the rotating body is stopped and the work device is operating automatically so that the ground angle of the bucket approaches the operation completion angle.

3. A work machine as described in claim 2, characterized in that, when the control device outputs the rotation operation start command at the current time, if it predicts that the rotation of the rotating body will start after the ground angle of the bucket reaches the operation completion angle, it determines that the rotation start condition is met.

4. A work machine as described in claim 2, wherein the control device calculates a first time from when the rotation operation start command is output to when the operation of the rotating body is started, calculates a second time from the current time until the ground angle of the bucket reaches the operation completion angle, and determines that the rotation start condition is met when the second time becomes shorter than the first time.

5. A work machine as described in claim 2, wherein the operation completion angle is a completion angle of the operation of the working device to release the excavated material in the bucket above the vessel, and the control device determines that the rotation start condition is met when, when the rotation start command is currently output, it is predicted that the rotation of the rotating body will start before the ground angle of the bucket reaches the operation completion angle, and that the bucket will start to go out of the vessel after the ground angle of the bucket reaches the operation completion angle.

6. A work machine as described in claim 5, wherein the control device calculates a first time from when the rotation operation start command is output until the operation of the rotating body starts, calculates a second time from the current time until the ground angle of the bucket reaches the operation completion angle, and calculates a third time from when the operation of the rotating body starts until the bucket begins to go outside the vessel, and determines that the rotation start condition is met when the second time becomes shorter than the sum of the first time and the third time.

7. A work machine as claimed in claim 1, characterized in that the control device determines that the turning start condition is met when the weight of the excavated material in the bucket reaches a predetermined weight.

8. A work machine as described in claim 1, characterized in that the control device acquires the weight of the excavated material in the bucket, and determines that the turning start condition is met when the acquired weight of the excavated material in the bucket reaches a predetermined weight.

9. A work machine as described in claim 7, characterized in that the control device determines whether or not the rotation start condition is satisfied when the rotation movement of the rotating body is stopped and the work device is operating to excavate the material, and determines that the rotation start condition is satisfied when the weight of the material in the bucket has increased to the specified weight.

10. A work machine as described in claim 7, characterized in that the control device determines whether or not the rotation start condition is satisfied when the rotation operation of the rotating body is stopped and the work device is operating to release the excavated material, and determines that the rotation start condition is satisfied when the weight of the excavated material in the bucket has decreased to the specified weight by releasing a specified percentage of the weight from before the release operation.

11. A work machine as claimed in claim 10, further comprising an input device capable of inputting the predetermined ratio, wherein the control device has a data table defining 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 ground angle of the bucket, refers to the data table and determines the ground angle of the bucket corresponding to the predetermined ratio input by the input device as a ground angle threshold, and when the ground angle of the bucket reaches the ground angle threshold, determines that the turning start condition is met.

12. A work machine as claimed in claim 11, characterized in that the input device is capable of inputting the soil properties of the excavated material, and the control device corrects the data table based on the soil properties of the excavated material input by the input device.

13. A work machine as described in claim 10, wherein the vessel position detection device is an object detection device that detects objects, and the control device determines whether or not the turning start condition is 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.

14. A work machine as described in claim 1, further comprising a rotation start operation device that is operated by an operator to instruct the start of rotation of the rotating body, wherein the control device determines whether or not the rotation start condition is satisfied when the rotation operation of the rotating body has stopped and the work device is operating, and determines that the rotation start condition is satisfied when the start of rotation of the rotating body is instructed by the rotation start operation device.

15. A work machine as described in claim 14, further comprising a work operation device that is operated by an operator to operate the work equipment, wherein the control device determines whether or not the rotation start condition is satisfied when the rotation operation of the rotating body has stopped and the work equipment is operating in response to the operation of the work operation device, and determines that the rotation start condition is satisfied when the rotation start operation device instructs the start of rotation of the rotating body.

16. A work machine as claimed in claim 6, characterized in that the control device calculates a 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, and calculates the second time by subtracting the elapsed time from the start time of the operation of discharging the excavated material in the bucket from the required discharge time.

Images