Work Machine

Abstract

The objective of the present invention is to provide a work machine that is able to set a target trajectory and a target posture of a work tool appropriately in accordance with the excavation environment and the excavation subject during automatic excavation control. For that purpose, in this invention, a control device calculates a target trajectory, which passes through an excavation starting position where a control point is located when excavation starts, an intermediate excavation position where the control point is located during excavation, and an excavation end position where the control point is located when excavation ends, and a target posture, which is a target posture of the work tool when the control point moves along the target trajectory, and the control device controls a control valve such that the control point moves along the target trajectory and such that the posture of the work tool matches the target posture while the control point moves along the target trajectory.

Description

[Technical field]

[0001] The present invention relates to a work machine that performs automatic excavation control, for example. [Background technology]

[0002] 2. Description of the Related Art Excavation and loading work involves excavating soil and sand using a work machine (e.g., a hydraulic excavator) equipped with a work implement (e.g., a front work implement) driven by a hydraulic actuator, and loading the soil and sand onto a transport vehicle (e.g., a dump truck) equipped with a transport implement (e.g., a vessel).

[0003] Research is being conducted into how to perform such excavation and loading work using automatic control. In automatic control of construction machinery, a motion plan is generally made to determine the trajectory along which the work equipment should move, and a target trajectory is then generated.

[0004] Patent Document 1 discloses a technique for generating a target trajectory based on the ratio of excavation depth to excavation length. In this document, the target trajectory is generated according to a predetermined excavation curve ratio expressed as the ratio of excavation depth to excavation length, and the desirable value of the excavation curve ratio is also mentioned. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-041354 A Summary of the Invention [Problem to be solved by the invention]

[0006] It is possible to generate a target trajectory for excavation work by a hydraulic excavator using the technology described in Patent Document 1. However, the appropriate excavation trajectory changes depending on the inclination of the excavation surface, the hardness of the excavation object, etc., but this is not mentioned. The environments and objects to be excavated in which hydraulic excavators are used are various, and if excavation work is performed with an inappropriate target trajectory, the bucket may not be able to excavate enough soil and sand, resulting in reduced work efficiency, or the bucket may sink too deep into the soil and become unable to move any further. Therefore, it is desirable to be able to generate an appropriate target trajectory for various inclinations of the excavation surface and hardness of the objects to be excavated.

[0007] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a work machine that is capable of appropriately setting a target trajectory and target attitude of a work tool in accordance with the excavation environment and the object to be excavated in automatic excavation control. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the present invention provides a work machine including a working device having a working implement, a hydraulic actuator for driving the working device, a hydraulic pump, a control valve for controlling the flow rate of pressurized oil supplied from the hydraulic pump to the hydraulic actuator, and a control device for calculating a target trajectory of a control point on the working implement and controlling the control valve so that the control point moves along the target trajectory, wherein the control device calculates a target trajectory that passes through an excavation start position where the control point is located at the start of excavation, a mid-excavation position where the control point is located during excavation, and an excavation end position where the control point is located at the end of excavation, based on inclination information of the excavation surface, and a target attitude of the working implement when the control point moves along the target trajectory, and controls the control valve so that the control point moves along the target trajectory and so that the attitude of the working implement when the control point moves along the target trajectory coincides with the target attitude.

[0009] According to the present invention configured as described above, the target trajectory and target posture of the work tool are calculated so that the control point on the work tool passes through the excavation start position, the excavation mid-point, and the excavation end position, making it possible to appropriately set the target trajectory and target posture according to the excavation environment and the object to be excavated. Effect of the Invention

[0010] According to the present invention, in automatic excavation control of a work machine, it is possible to appropriately set a target trajectory and a target attitude of a work implement according to the excavation environment and the object to be excavated. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a configuration diagram of a hydraulic excavator according to a first embodiment of the present invention. [Diagram 2] A functional block diagram of a control device according to a first embodiment of the present invention. [Figure 3A] 1 is a flowchart of automatic operation control by a control device according to a first embodiment of the present invention (1 / 2). [Figure 3B] Flowchart (2 / 2) of automatic operation control by the control device in the first embodiment of the present invention [Figure 4] 1 is a flowchart showing parameter setting according to the inclination of an excavation surface by a control device according to a first embodiment of the present invention; [Diagram 5] FIG. 1 is an explanatory diagram of an excavation trajectory generated by a control device according to an inclination of an excavation surface in a first embodiment of the present invention; [Figure 6] A functional block diagram of a control device according to a second embodiment of the present invention. [Figure 7] 11 is a flowchart showing parameter setting according to the inclination of the excavation surface and the hardness of the excavation target by the control device in the second embodiment of the present invention. [Figure 8] FIG. 11 is an explanatory diagram of an excavation trajectory generated by a control device according to the inclination of the excavation surface and the hardness of the object to be excavated in a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following, a hydraulic excavator equipped with a bucket as a working tool (attachment) at the tip of a working device will be exemplified, but the present invention may be applied to a working machine equipped with an attachment other than a bucket. Furthermore, the present invention may be applied to a working machine other than a hydraulic excavator as long as it has a multi-joint type working device configured by connecting multiple link members (attachments, arms, booms, etc.). EXAMPLES

[0013] FIG. 1 is a configuration diagram of a hydraulic excavator according to a first embodiment of the present invention. In FIG. 1, the hydraulic excavator 1 is composed of an articulated front working device 1A and a vehicle body 1B. The vehicle body 1B is composed of a lower traveling body 11 that travels by left and right traveling hydraulic motors 3 (only the left one is shown), and an upper rotating body 12 that is attached on the lower traveling body 11 and rotates by a swing hydraulic motor 4. The front working device 1A is composed of a plurality of driven members (a boom 8, an arm 9, and a bucket 10) that each rotate in a vertical direction, which are connected together. The base end of the boom 8 is rotatably supported via a boom pin at the front of the upper rotating body 12. The arm 9 is rotatably connected to the tip of the boom 8 via an arm pin, and the bucket 10 is rotatably connected to the tip of the arm 9 via a bucket pin. The boom 8 is driven by a boom cylinder 5, the arm 9 is driven by an arm cylinder 6, and the bucket 10 is driven by a bucket cylinder 7.

[0014] An engine 18, which is a prime mover mounted on the upper rotating body 12, drives the hydraulic pump 2. The pressure oil discharged from the hydraulic pump 2 is supplied to the traveling hydraulic motor 3, the swing hydraulic motor 4, the boom cylinder 5, the arm cylinder 6, and the bucket cylinder 7 via a control valve 20. The control valve 20 is composed of a plurality of flow control valves that control the flow rate of the pressure oil supplied to each of the hydraulic actuators 3 to 7. The boom cylinder 5, the arm cylinder 6, and the bucket cylinder 7 are expanded and contracted by the supplied pressure oil, so that the boom 8, the arm 9, and the bucket 10 rotate, respectively, and the position and attitude of the bucket 10 change. In addition, the swing hydraulic motor 4 is rotated by the supplied pressure oil, so that the upper rotating body 12 rotates relative to the lower traveling body 11. Then, the traveling hydraulic motor 3 is rotated by the supplied pressure oil, so that the lower traveling body 11 travels.

[0015] In the automatic operation control, the flow control valves that adjust the flow rate of pressure oil supplied to the boom cylinder 5, arm cylinder 6, and bucket cylinder 7 are driven by pilot hydraulic signals from solenoid proportional valves 54-59 (shown in FIG. 2) to operate the traveling hydraulic motor 3, swing hydraulic motor 4, boom cylinder 5, arm cylinder 6, and bucket cylinder 7. The solenoid proportional valves 54-59 are controlled by control commands from the control device 40. Note that the automatic operation control when performing an excavation operation is sometimes referred to as automatic excavation control.

[0016] A boom angle sensor 30 is attached to the boom 8, an arm angle sensor 31 to the arm 9, and a bucket angle sensor 32 to the bucket link 13 so as to be able to measure the rotation angles of the boom 8, arm 9, and bucket 10, a vehicle body inclination angle sensor 33 is attached to the upper rotating body 12 to detect the inclination angle of the upper rotating body 12 (vehicle body 1B) relative to a reference plane (e.g., a horizontal plane), and a vehicle body position detection device 36 is attached to detect the position of the vehicle body 1B.

[0017] The working implement attitude detection device 50 is made up of a boom angle sensor 30, an arm angle sensor 31, a bucket angle sensor 32, and a vehicle body inclination angle sensor 33. These angle sensors 30 to 33 function as attitude sensors for the front working implement 1A.

[0018] 2 is a functional block diagram of the control device 40. The control device 40 includes a position and attitude calculation unit 43, an electromagnetic proportional valve control unit 44, an actuator control unit 81, a motion planning unit 90, an automatic motion control unit 91, a track deviation determination unit 92, a time deviation determination unit 93, a first input unit 100, a second input unit 101, a third input unit 102, an excavation surface inclination setting unit 103, a first output unit 110, and a second output unit 111. The control device 40 includes a controller having a calculation function, an input / output interface for inputting and outputting signals between the controller and an external device, and the functions of each unit are realized by executing a program stored in a storage device such as a ROM.

[0019] The first input unit 100 receives task information from an external connection device 200 .

[0020] The second input unit 101 receives an approval signal or a non-approval signal from the external connection device 200 .

[0021] A task pause signal, a task restart request signal, or a task midway termination request signal is input to the third input unit 102 from the external connection device 200 .

[0022] The excavation surface inclination setting unit 103 sets an inclination of the excavation surface that generally matches the inclination of the terrain surrounding the location where excavation work is performed by the front working implement 1A, based on information from the external connection device 200. The information input from the external connection device 200 to the excavation surface inclination setting unit 103 may be the result of a person visually checking the inclination of the terrain, or the result of measurement using a terrain measurement sensor or the like.

[0023] The position and attitude calculation unit 43 calculates the position coordinates of the hydraulic excavator 1, the attitude of the front working implement 1A, and the tip position (control point) of the bucket 10 based on information from the working implement attitude detection device 50 and the vehicle body position detection device .

[0024] The motion planning unit 90 prestores a table of parameters used to calculate a planned motion trajectory (target trajectory), and calculates planned position coordinates of the hydraulic excavator 1, planned attitude of the front working implement 1A, and planned motion trajectory of the toe position of the bucket 10 at each time from the start of the task to the end of the task based on the task information acquired from the first input unit 100 and the inclination information of the excavation surface acquired from the excavation surface inclination setting unit 103, and outputs these to the automatic motion control unit 91, the trajectory deviation determination unit 92, the time deviation determination unit 93, and the first output unit 110. Hereinafter, the planned motion trajectory from the excavation start position to the excavation end position may be referred to as the excavation trajectory.

[0025] Based on the motion planning information from the motion planning unit 90, the current posture information of the front working implement 1A from the position and posture calculation unit 43, and the tiptoe position information of the bucket 10, the trajectory deviation determination unit 92 determines whether or not the actual motion trajectory of the tiptoe position of the bucket 10 deviates from the planned motion trajectory planned by the motion planning unit 90 by more than a preset first allowable position error, and outputs the determination result to the automatic motion control unit 91.

[0026] The time deviation determination unit 93 determines whether or not the actual operations of the front working implement 1A, the swing hydraulic motor 4 and the traveling hydraulic motor 3 deviate from the operations planned by the motion planning unit 90 by more than a preset first allowable time error, based on the motion plan information from the motion planning unit 90 and the current attitude information of the front working implement 1A from the position and attitude calculation unit 43, and outputs the determination result to the automatic motion control unit 91.

[0027] The automatic operation control unit 91 calculates a speed command for each hydraulic actuator based on the operation plan information from the operation plan unit 90 only when the signal from the second input unit 101 is an approval signal, and outputs the calculated speed command to the actuator control unit 81. When the trajectory deviation determination unit 92 determines that the trajectory has deviated during task execution, or when the time deviation determination unit 93 determines that the operation time has deviated, the automatic operation control unit 91 terminates task execution and outputs an abnormal end signal to the second output unit 111. When the signal from the third input unit 102 is a task pause request signal, the automatic operation control unit 91 pauses task execution and outputs a pause signal to the second output unit 111, when a task resume request signal is received from the third input unit 102 during the task pause, the automatic operation control unit 91 resumes task execution, and when a task mid-termination request signal is received from the third input unit 102, the automatic operation control unit 91 terminates task execution and outputs a mid-termination signal to the second output unit 111. When the task is completed without deviating from the planned operation trajectory and operation time, the automatic operation control unit 91 outputs a normal end signal.

[0028] The actuator control unit 81 calculates the target pilot pressure for the flow control valve of each hydraulic actuator based on the speed commands for each hydraulic actuator 3 to 7 output from the automatic operation control unit 91, and outputs the calculated target pilot pressure to the solenoid proportional valve control unit 44.

[0029] The electromagnetic proportional valve control section 44 calculates commands to each of the electromagnetic proportional valves 54 to 59 based on the target pilot pressures to each flow control valve output from the actuator control section 81.

[0030] The first output unit 110 outputs the operation plan information output from the operation plan unit 90 to the external connection device 200 .

[0031] The second output unit 111 outputs a normal end signal, an abnormal end signal, a temporary interruption signal, or an intermediate end signal output from the automatic operation control unit 91 to the external connection device 200 .

[0032] 3A and 3B are flowcharts showing automatic operation control by the control device 40. Each step will be described below in order.

[0033] In step S 110 , the first input unit 100 acquires task information input from the external connection device 200 .

[0034] In step S120, based on the task information acquired in step S110, the motion planning unit 90 calculates the planned motion trajectory of the hydraulic excavator 1 at each time from the start of the task to the end of the task, i.e., the planned position coordinates of the hydraulic excavator 1 and the planned posture (target posture) of the front working implement 1A.

[0035] In step S130, the first output unit outputs the result of the operation plan calculated in step S120 to the external connection device 200.

[0036] In step S140, the second input unit 101 acquires an approval signal or a disapproval signal from the external connection device 200.

[0037] In step S150, it is determined whether the signal of the second input unit 101 acquired in step S140 is an approval signal. If it is determined in step S150 that the signal of the second input unit 101 is an approval signal, the process proceeds to step S160, and if it is determined in step S150 that the signal of the second input unit 101 is not an approval signal, the process proceeds to step S110.

[0038] In step S160, the actuator control section 81 calculates the target speed of each of the hydraulic actuators 3 to 7 from the operation plan result calculated in step S120.

[0039] In step S170, the actuator control section 81 outputs to the solenoid proportional valve control section 44 the target speeds of the hydraulic actuators 3 to 7 calculated in step S160.

[0040] In step S180, the trajectory deviation determination unit 92 and the time deviation determination unit 93 acquire the position coordinates of the hydraulic excavator 1 calculated by the position and attitude calculation unit 43, the attitude of the front working implement 1A, and the tip position of the bucket 10.

[0041] In step S190, trajectory deviation determination unit 92 determines, from the position and attitude information acquired in step S180, whether the deviation of the current toe position of bucket 10 from the planned motion trajectory calculated by motion planning unit 90 is equal to or smaller than a first allowable position error. If it is determined in step S190 that the deviation is equal to or smaller than the first allowable position error, the process proceeds to step S200, and if it is determined in step S190 that the deviation is larger than the first allowable position error, the process proceeds to step S250.

[0042] In step S200, the time deviation determination unit 93 determines whether the deviation of the current position coordinates of the hydraulic excavator 1 and the planned position coordinates of the hydraulic excavator 1 and the planned attitude of the front working implement 1A at each time calculated by the motion planning unit 90 is equal to or smaller than a first allowable time error, based on the position and attitude information acquired in step S180. If it is determined in step S200 that the deviation is equal to or smaller than the first allowable time error, the process proceeds to step S210, and if it is determined in step S200 that the deviation is larger than the first allowable time error, the process proceeds to step S250.

[0043] In step S210, the third input unit 102 acquires a signal from the external connection device 200.

[0044] In step S220, it is determined whether the signal of the third input unit 102 acquired in step S210 is a task pause request signal. If it is determined in step S220 that the signal of the third input unit 102 is a task pause request signal, the process proceeds to step S260, and if it is determined in step S220 that the signal of the third input unit 102 is other than a task pause request signal, the process proceeds to step S230.

[0045] In step S230, it is determined whether or not the execution of the task based on the motion plan calculated in step S120 has been completed. If it is determined in step S230 that the execution of the task has been completed, the process proceeds to step S240, and if it is determined in step S230 that the execution of the task has not been completed, the process proceeds to step S160.

[0046] In step S240, the second output unit 111 outputs a normal end signal to the external connection device 200.

[0047] In step S250, the second output unit 111 outputs an abnormal end signal to the external connection device 200.

[0048] In step S260, the second output unit 111 outputs a pause signal to the external connection device 200.

[0049] In step S270, the third input unit 102 acquires a signal from the external connection device 200.

[0050] In step S280, it is determined whether the signal of the third input unit 102 acquired in step S270 is a task restart request signal. If it is determined in step S280 that the signal of the third input unit 102 is a task restart request signal, the process proceeds to step S230, and if it is determined in step S280 that the signal of the third input unit 102 is other than a task restart request, the process proceeds to step S290.

[0051] In step S290, it is determined whether the signal of the third input unit 102 acquired in step S270 is a task mid-termination request signal. If it is determined in step S290 that the signal of the third input unit 102 is a task mid-termination request signal, the process proceeds to step S300, and if it is determined in step S290 that the signal of the third input unit 102 is other than a task mid-termination request signal, the process proceeds to step S270.

[0052] In step S300, the second output unit 111 outputs an intermediate end signal to the external connection device 200.

[0053] 4 is a flowchart of parameter setting according to the inclination of the excavation surface by the motion planning unit 90. The parameters referred to here are the distance from the excavation start position to the excavation end position (excavation distance), the maximum excavation depth, the maximum excavation depth position, the motion end position, and the attitude of the bucket 10 at each position, which are used when calculating the planned motion trajectory of the toe position of the bucket 10. Each step will be described below in order.

[0054] In step S400, the excavation surface inclination setting unit 103 sets an excavation surface inclination θ_gnd that roughly matches the inclination of the terrain around the location where excavation work is performed by the front working implement 1A from the external connection device 200. Note that the inclination θ_gnd of the excavation surface in this embodiment is defined as positive when it is inclined downward as viewed from the vehicle body 1B (as shown in FIG. 5) and as negative when it is inclined upward.

[0055] In step S410, parameters related to length in the calculation of the planned movement trajectory are set according to the inclination θ_gnd of the excavation surface set in step S400. Specifically, the excavation distance L_ex from the excavation start position, the maximum excavation depth D_maxdpt, and the distance L_maxdpt in the excavation surface direction to the maximum excavation depth position are set.

[0056] In step S420, parameters related to the posture in the calculation of the planned operation trajectory are set according to the inclination θ_gnd of the excavation surface set in step S400. Specifically, the posture θ_1 of the bucket 10 at the excavation start position, the posture θ_2 of the bucket 10 at the maximum excavation depth position, and the posture θ_3 of the bucket 10 at the excavation end position are set. Note that, in the postures θ_1 to θ_3 of the bucket 10 in this embodiment, the displacement on the cloud side (counterclockwise direction in FIG. 5) is defined as positive, and the displacement on the dump side (clockwise direction in FIG. 5) is defined as negative.

[0057] In step S430, parameters that are not dependent on the inclination θ_gnd of the excavation surface in the calculation of the planned movement trajectory are set. Specifically, the distance L_fin in the direction of the excavation surface to the movement end position and the attitude θ_4 of the bucket 10 at the movement end position are set.

[0058] In step S440, a planned operating trajectory is calculated so as to smoothly connect each position and each posture based on the excavation start position, maximum excavation depth position, excavation end position, operation end position, and the posture of the bucket 10 at each position, which are obtained from the parameters set in steps S410, S420, and S430.

[0059] 4 is just an example, and the parameters may be set according to the inclination θ_gnd of the excavation surface by another method. Alternatively, each position and the attitude of the bucket 10 at each position may be set directly according to the inclination θ_gnd of the excavation surface without using parameters.

[0060] When calculating a planned motion trajectory so as to smoothly connect each position and each orientation, interpolation using Lagrange interpolation, Bezier interpolation, Hermite interpolation, spline interpolation, etc. is considered, but other methods may also be used.

[0061] In the hydraulic excavator 1 configured as above, an excavation trajectory generated in accordance with the inclination θ_gnd of the excavation surface is shown in FIG.

[0062] An administrator or a management system inputs task information and the inclination θ_gnd of the excavation surface. The motion planning unit 90 performs motion planning based on the input task information and the inclination θ_gnd of the excavation surface. That is, it calculates the planned position coordinates of the hydraulic excavator 1, the planned attitude of the front working implement 1A, and the planned motion trajectory of the toe position of the bucket 10 at each time from the start of the task to the end of the task. In the calculation of the planned motion trajectory, the motion planning unit 90 calculates a planned motion trajectory according to the inclination θ_gnd of the excavation surface when generating an excavation motion trajectory. In FIG. 5, since the excavation surface is inclined downward, in step S410 the excavation distance L_ex is set shorter, the maximum excavation depth D_maxdpt is set deeper, and the distance L_maxdpt in the excavation surface direction to the maximum excavation depth position is set longer than when the excavation surface is not inclined, i.e., when θ_gnd=0. Similarly, in step S420, compared to the case where θ_gnd=0, the attitude θ_1 of the bucket 10 at the excavation start position is set larger, the attitude θ_2 of the bucket 10 at the maximum excavation depth position is set larger, and the attitude θ_3 of the bucket 10 at the excavation end position is set larger. In step S430, the distance L_fin in the excavation surface direction to the operation end position and the attitude θ_4 of the bucket 10 at the operation end position are set independent of the inclination θ_gnd of the excavation surface, and the attitude θ_4 of the bucket 10 at the operation end position is set according to the direction of gravity. The attitude θ_4 here is, for example, an attitude in which a straight line connecting the bucket pin and the bucket tip is approximately horizontal. This determines the positions P1 to P4 of the tip of the bucket 10 and the attitude of the bucket 10 in state S1 (excavation start state), state S2 (maximum excavation depth state), state S3 (excavation end state), and state S4 (operation end state) in FIG. 5. In step S440, a planned motion trajectory R (target trajectory) is calculated so as to smoothly connect position P1 to position P4.

[0063] The result of the operation plan is output from the first output unit 110 and is presented to the administrator or management system via the external connection device 200. If there is no problem with the result of the operation plan, an approval signal is input from the administrator or management system to the second input unit 101, and the result is determined as YES in step S150 in FIG.

[0064] Next, the automatic operation control unit 91 calculates speed commands for the hydraulic actuators 3 to 7 based on the planned operation trajectory R, ​​the actuator control unit 81 calculates target pilot pressures for the flow control valves of the hydraulic actuators, and the electromagnetic proportional valves 54 to 59 are actually driven by control signals from the electromagnetic proportional valve control unit 44, thereby executing the automatic operation. During the execution of the automatic operation, in step S190 of FIG. 3, it is determined whether the deviation of the current tip end position of the bucket 10 from the planned operation trajectory R calculated in the motion planning unit 90 is equal to or smaller than a first allowable position error, and in step S200 of FIG. 3, it is determined whether the deviation of the current position coordinates of the hydraulic excavator 1 and the attitude of the front working implement 1A from the planned position coordinates of the hydraulic excavator 1 and the planned attitude of the front working implement 1A at each time calculated in the motion planning unit 90 is equal to or smaller than a first allowable time error. If the automatic operation is being performed according to the motion plan, it is determined as YES in steps S190 and S200 of FIG. 3, but there are cases in which the automatic operation cannot be performed according to the motion plan depending on the soil quality of the excavation target, etc. 3, the result is NO, an abnormal end signal is output from the second output unit 111, and the manager or management system is notified that the task has ended abnormally, and then execution of the task is terminated. This makes it possible to prevent operations that are not approved by the manager or management system.

[0065] If for some reason it is desired to temporarily suspend the automatic operation of the hydraulic excavator 1 during task execution, a task temporary suspension request signal is input from the administrator or management system to the third input unit 102. In this case, the determination in step S220 in Fig. 3 is YES, a temporary suspension signal is output from the second output unit 111 to the administrator or management system, and execution of the task is temporarily suspended.

[0066] When it is desired to resume execution of a task while it is paused, a task resume request signal is input from the administrator or management system to the third input unit 102. In this case, the determination is YES in step S280 in Fig. 3 and execution of the task is resumed. Also, when it is desired to end the task midway while it is paused, a task midway end request signal is input from the administrator or management system to the third input unit 102. In this case, the determination is YES in step S290 in Fig. 3 and an midway end signal is output from the second output unit 111 to inform the administrator or management system that the task has been midway ended, and then execution of the task is ended.

[0067] Next, when the execution of the task is completed, the result of the determination in step S230 of FIG. 3 is YES, a normal end signal is output from the second output unit 111, and the administrator or management system is notified that the task has been completed normally, and then the execution of the task is terminated.

[0068] By configuring the hydraulic excavator as described above, it is possible to generate an appropriate excavation trajectory for various excavation surface inclinations θ_gnd and perform automatic operations.

[0069] (summary) In this embodiment, in a work machine 1 including a work implement 1A having a work tool 10, hydraulic actuators 5-7 for driving the work implement 1A, a hydraulic pump 2, a control valve 20 for controlling the flow rate of pressurized oil supplied from the hydraulic pump 2 to the hydraulic actuators 5-7, and a control device 40 for calculating a target trajectory R for a control point on the work implement 10 (for example, the tip position of the bucket 10) and controlling the control valve 20 so that the control point moves along the target trajectory R, ​​the control device 40 calculates, based on inclination information of the excavation surface, a target trajectory R passing through an excavation start position P1 where the control point is located at the start of excavation, a mid-excavation position P2 where the control point is located during excavation, and an excavation end position P3 where the control point is located at the end of excavation, as well as a target attitude of the work implement 10 when the control point moves along the target trajectory R, ​​and controls the control valve 20 so that the control point moves along the target trajectory R and so that the attitude of the work implement 10 when the control point moves along the target trajectory R coincides with the target attitude.

[0070] According to this embodiment configured as described above, the target trajectory R and target attitudes θ_1 to θ_3 of the work tool 10 are calculated so that the control point on the work tool 10 passes through the excavation start position P1, the mid-excavation position P2, and the excavation end position P3, so that the target trajectory R and target attitudes θ_1 to θ_3 can be appropriately set according to the excavation environment and the object to be excavated.

[0071] Moreover, the mid-excavation position P2 in this embodiment is the maximum excavation depth position located deepest from the ground surface on the target trajectory R. This allows the target trajectory to be calculated so as to pass through points located on the ground surface (the excavation start position P1 and the excavation end position P3) and the point located deepest from the ground surface (the maximum excavation depth position P2), making it possible to set the target trajectory more appropriately.

[0072] Furthermore, the control device 40 in this embodiment calculates the target trajectory R so as to pass through the excavation start position P1, the maximum excavation depth position P2, and the excavation end position P3, as well as the operation end position P4 where the control point is located when the excavation operation ends. This makes it possible to control a series of operations up to scooping the excavated soil with the work tool 10 based on the target trajectory.

[0073] In addition, the control device 40 in this embodiment calculates the target attitude θ_4 of the working tool 10 at the operation end position P4 based on the direction of gravity, not on the inclination of the excavation surface as the inclination information of the excavation surface. This makes it possible to prevent the soil scooped by the working tool 10 from spilling out of the working tool 10.

[0074] Furthermore, the work machine 1 in this embodiment is equipped with an external connection device 200 that inputs the inclination θ_gnd of the excavation surface to the control device 40 as the inclination information of the excavation surface, and the control device 40 sets the excavation start position P1, maximum excavation depth position P2, and excavation end position P3 according to the inclination θ_gnd of the excavation surface. This makes it possible to appropriately set the excavation start position P1, maximum excavation depth position P2, and excavation end position P3 according to the inclination θ_gnd of the excavation surface.

[0075] Furthermore, the control device 40 in this embodiment calculates the target attitude θ_1 at the excavation start position P1, the target attitude θ_2 at the maximum excavation depth position P2, and the target attitude θ_3 at the excavation end position P3 according to the inclination θ_gnd of the excavation surface. This makes it possible to appropriately set the target attitudes θ_1 to θ_3 of the work tool 10 at the excavation start position P1, the maximum excavation depth position P2, and the excavation end position P3 according to the inclination θ_gnd of the excavation surface.

[0076] In addition, the control device 40 in this embodiment sets the maximum excavation depth position P2 to be closer to the excavation start position P1 as the downward slope of the excavation surface becomes smaller or the upward slope of the excavation surface becomes larger, sets the maximum excavation depth position P2 to be closer to the excavation end position P1 as the upward slope of the excavation surface becomes smaller or the downward slope of the excavation surface becomes larger, sets the maximum excavation depth position P2 to a shallower position from the ground surface as the downward slope of the excavation surface becomes smaller or the upward slope of the excavation surface becomes larger, and sets the maximum excavation depth position P2 to a deeper position from the ground surface as the upward slope of the excavation surface becomes smaller or the downward slope of the excavation surface becomes larger. This makes it possible to set a target trajectory with high excavation efficiency.

[0077] In addition, the control device 40 in this embodiment sets the excavation start position P1 and the excavation end position P3 so that the distance from the excavation start position P1 to the excavation end position P3 (excavation distance L_ex) becomes shorter as the upward inclination of the excavation surface becomes smaller or the downward inclination of the excavation surface becomes larger. It becomes possible to adjust the excavation distance L_ex according to the inclination θ_gnd of the excavation surface. EXAMPLES

[0078] A second embodiment of the present invention will be described, focusing on the differences from the first embodiment.

[0079] 6 is a functional block diagram of the control device 40 in this embodiment. The control device 40 includes a position and attitude calculation unit 43, an electromagnetic proportional valve control unit 44, an actuator control unit 81, a motion planning unit 90, an automatic motion control unit 91, a trajectory deviation determination unit 92, a time deviation determination unit 93, a first input unit 100, a second input unit 101, a third input unit 102, an excavation surface inclination setting unit 103, an excavation target hardness setting unit 104, a first output unit 110, and a second output unit 111.

[0080] The hardness of the excavation object is set in the excavation object hardness setting unit 104 based on information from the external connection device 200. The information input from the external connection device 200 to the excavation object hardness setting unit 104 may be a result of visual estimation by a person or a result of measurement by a sensor or the like.

[0081] The motion planning unit 90 pre-stores a table of parameters used to calculate the planned motion trajectory R, ​​and calculates the planned position coordinates of the hydraulic excavator 1, the planned attitude of the front working implement 1A, and the planned motion trajectory R of the toe position of the bucket 10 at each time from the start of the task to the end of the task based on the task information acquired from the first input unit 100, the excavation surface inclination information acquired from the excavation surface inclination setting unit 103, and the hardness information of the excavation object acquired from the excavation object hardness setting unit 104, and outputs these to the automatic motion control unit 91, the trajectory deviation determination unit 92, the time deviation determination unit 93, and the first output unit 110.

[0082] 7 is a flowchart showing parameter setting by the control device 40 according to the inclination θ_gnd of the excavation surface and the hardness H_gnd of the object to be excavated. The parameters referred to here are the distance from the excavation start position P1 to the excavation end position P3 (excavation distance L_ex), the maximum excavation depth D_maxdpt, the maximum excavation depth position P2, the operation end position P4, and the attitudes θ_1 to θ_4 of the bucket 10 at each position, which are used when calculating the expected operation trajectory R of the toe position of the bucket 10. Each step will be described below in order.

[0083] In step S500, the excavation surface inclination setting section 103 receives from the external connection device 200 and sets an excavation surface inclination θ_gnd that roughly matches the inclination of the terrain surrounding the location where excavation work is to be performed by the front working implement 1A.

[0084] In step S510, the excavation object hardness setting section 104 receives from the external connection device 200 the hardness H_gnd of the excavation object around the location where excavation work is to be performed by the front working implement 1A.

[0085] In step S520, among the parameters related to length in the calculation of the planned motion trajectory R, ​​those determined only by the inclination θ_gnd of the excavation surface set in step S500 are set. Specifically, the excavation distance L_ex from the excavation start position P1 and the distance L_maxdpt in the excavation surface direction to the maximum excavation depth position P2 are set.

[0086] In step S530, a table to be used is extracted from a table of the maximum excavation depth D_maxdpt, the attitude θ_1 of the bucket 10 at the excavation start position P1, the attitude θ_2 of the bucket 10 at the maximum excavation depth position P2, and the attitude θ_3 of the bucket 10 at the excavation end position P3 pre-stored in the motion planning unit 90, depending on the hardness H_gnd of the excavation object set in step S510.

[0087] In step S540, among the parameters related to the posture in the calculation of the expected motion trajectory R, ​​those determined by both the inclination θ_gnd of the excavation surface set in step S500 and the hardness H_gnd of the excavation object set in step S510 are set. Specifically, the maximum excavation depth D_maxdpt, the posture θ_1 of the bucket 10 at the excavation start position P1, the posture θ_2 of the bucket 10 at the maximum excavation depth position P2, and the posture θ_3 of the bucket 10 at the excavation end position P3 are set. In step S530, a table to be used is selected according to the hardness H_gnd of the excavation object, and in step S540, a parameter according to the inclination θ_gnd of the excavation surface is set from the table, so that a parameter considering both the inclination θ_gnd of the excavation surface and the hardness H_gnd of the excavation object can be selected. In the example shown in FIG. 7, one table is selected from three tables (indicated by solid lines, dashed lines, and dotted lines in the figure, respectively) for the case where the hardness H_gnd is normal, slightly large, and large. As shown in FIG. 7, even if the inclination θ_gnd of the excavation face is the same, as the hardness H_gnd increases, the maximum excavation depth D_maxdpt decreases and the attitudes θ_1 to θ_4 of the bucket 10 increase.

[0088] In step S550, a parameter is set that is not dependent on the inclination θ_gnd of the excavation surface or the hardness H_gnd of the excavation object in the calculation of the planned movement trajectory R. Specifically, the distance L_fin in the excavation surface direction to the movement end position P4 and the attitude θ_4 of the bucket 10 at the movement end position P4 are set.

[0089] In step S560, a planned operating trajectory R is calculated so as to smoothly connect each position and posture based on the excavation start position P1, maximum excavation depth position P2, excavation end position P3, and operation end position P4 obtained from the parameters set in steps S520, S540, and S550, and the postures θ_1 to θ_4 of the bucket 10 at each position.

[0090] 7 is just an example, and the parameters may be set according to the inclination θ_gnd of the excavation surface and the hardness H_gnd of the object to be excavated by another method. Alternatively, each position and the attitude of the bucket 10 at each position may be set directly according to the inclination θ_gnd of the excavation surface and the hardness H_gnd of the object to be excavated without using parameters.

[0091] Furthermore, when calculating the planned motion trajectory R so as to smoothly connect each position and each orientation, interpolation using Lagrange interpolation, Bezier interpolation, Hermite interpolation, spline interpolation, etc. is considered, but other methods may also be used.

[0092] In the hydraulic excavator 1 configured as described above, an excavation trajectory generated according to the inclination θ_gnd of the excavation surface and the hardness H_gnd of the object to be excavated is shown in Fig. 8. Note that in Fig. 8, it is assumed that the hardness H_gnd of the ground around the location where excavation is performed by the front working implement 1A is large.

[0093] An administrator or management system inputs task information, the inclination θ_gnd of the excavation surface, and the hardness H_gnd of the object to be excavated. The motion planner 90 performs motion planning based on the input task information, the inclination θ_gnd of the excavation surface, and the hardness H_gnd of the object to be excavated. In other words, it calculates the planned position coordinates of the hydraulic excavator 1, the planned attitude of the front working implement 1A, and the planned motion trajectory R of the toe position of the bucket 10 at each time from the start of the task to the end of the task.

[0094] The motion planning unit 90 calculates a planned motion trajectory R according to the inclination θ_gnd of the excavation surface and the hardness H_gnd of the excavation object when generating an excavation motion trajectory in the calculation of the planned motion trajectory R. Since the excavation surface is inclined downward in Fig. 8, the excavation distance L_ex is set shorter in step S520 and the distance L_maxdpt in the excavation surface direction to the maximum excavation depth position P2 is set longer than when the excavation surface is not inclined, i.e., when θ_gnd = 0.

[0095] In addition, in step S530, since the parameters of the maximum excavation depth D_maxdpt, the attitude θ_1 of the bucket 10 at the excavation start position P1, the attitude θ_2 of the bucket 10 at the maximum excavation depth position P2, and the attitude θ_3 of the bucket 10 at the excavation end position P3 are large in relation to the hardness H_gnd of the excavation object, a table corresponding to the hardness H_gnd of the excavation object is extracted from the parameter tables pre-stored in the motion planning unit 90. At this time, a table with a shallower maximum excavation depth D_maxdpt is extracted compared to when the hardness H_gnd of the excavation object is normal, a table with an attitude θ_1 of the bucket 10 at the excavation start position P1 in which the orientation of the bottom of the bucket 10 approaches the tangent direction of the target trajectory is extracted, a table with an attitude θ_2 of the bucket 10 at the maximum excavation depth position P2 in which the orientation of the bottom of the bucket 10 approaches the tangent direction of the target trajectory is extracted, and a table with an attitude θ_3 of the bucket 10 at the excavation end position P3 in which the orientation of the bottom of the bucket 10 approaches the tangent direction of the target trajectory is extracted.

[0096] Compared to the case where θ_gnd = 0 from the table extracted in step S540, the maximum excavation depth D_maxdpt is set deeper, the attitude θ_1 of the bucket 10 at the excavation start position P1 is set larger, the attitude of the bucket 10 at the maximum excavation depth position P2 is set larger, and the attitude of the bucket 10 at the excavation end position P3 is set larger.

[0097] In step S550, the distance L_fin in the excavation surface direction to the operation end position P4 and the attitude θ_4 of the bucket 10 at the operation end position P4 are set independent of the inclination θ_gnd of the excavation surface, and the attitude θ_4 of the bucket 10 at the operation end position P4 is set according to the direction of gravity. This determines the toe position of the bucket 10 and the attitude of the bucket 10 in state S1 (excavation start state), state S2 (maximum excavation depth state), state S3 (excavation end state), and state S4 (operation end state) in Fig. 8. In step S560, a planned operation trajectory R is calculated so as to smoothly connect position P1 to position S4.

[0098] (summary) The work machine 1 in this embodiment is equipped with an external connection device 200 that inputs the hardness H_gnd of the excavation object to the control device 40, and the control device 40 sets the maximum excavation depth position P2 in accordance with the hardness H_gnd of the excavation object.

[0099] According to this embodiment configured as described above, in automatic excavation control, the maximum excavation depth position P2, which is located deepest from the ground surface on the target trajectory R, ​​can be appropriately set in accordance with the hardness H_gnd of the object to be excavated.

[0100] Furthermore, the control device 40 in this embodiment calculates the target attitude θ_1 at the excavation start position P1, the target attitude θ_2 at the maximum excavation depth position P2, and the target attitude θ_3 at the excavation end position P3 according to the hardness H_gnd of the excavation object. This makes it possible to appropriately set the target attitudes θ_1 to θ_3 of the work tool 10 at the excavation start position P1, the maximum excavation depth position P2, and the excavation end position P3 according to the hardness H_gnd of the excavation object.

[0101] Furthermore, the control device 40 in this embodiment calculates the target attitudes θ_1 to θ_3 so that the orientation of the bottom surface of the work tool 10 approaches the orientation of the tangent to the target trajectory R as the hardness H_gnd of the excavation target increases. This makes it possible to accurately excavate the object along the target trajectory even if the object is harder than usual.

[0102] In addition, in this embodiment, the external connection device 200 inputs the inclination θ_gnd of the excavation surface to the control device 40, and the control device 40 sets the maximum excavation depth position P2 to be closer to the excavation start position P1 as the downward inclination of the excavation surface becomes smaller or the upward inclination of the excavation surface becomes larger, sets the maximum excavation depth position P2 to be closer to the excavation end position P3 as the upward inclination of the excavation surface becomes smaller or the downward inclination of the excavation surface becomes larger, sets the maximum excavation depth position P2 to a shallower position from the ground surface as the hardness H_gnd of the excavation object becomes larger, sets the maximum excavation depth position P2 to a deeper position from the ground surface as the hardness H_gnd of the excavation object becomes smaller, sets the maximum excavation depth position P2 to a shallower position from the ground surface as the downward inclination of the excavation surface becomes smaller or the upward inclination of the excavation surface becomes larger, sets the maximum excavation depth position P2 to a shallower position from the ground surface, and sets the maximum excavation depth position P2 to a deeper position from the ground surface as the upward inclination of the excavation surface becomes smaller or the downward inclination of the excavation surface becomes larger. This makes it possible to appropriately set the maximum excavation depth position P2 in accordance with the inclination of the excavation surface and the hardness H_gnd of the object to be excavated.

[0103] Although the embodiments of the present invention have been described above in detail, the present invention is not limited to the above-mentioned embodiments, and various modifications are included. For example, the above-mentioned embodiments have been described in detail to easily explain the present invention, and the present invention is not necessarily limited to those having all of the configurations described. In addition, it is possible to add a part of the configuration of one embodiment to the configuration of another embodiment, and it is also possible to delete a part of the configuration of one embodiment, or to replace it with a part of another embodiment. [Explanation of symbols]

[0104] 1...hydraulic excavator (working machine), 1A...front working device, 1B...vehicle body, 2...hydraulic pump, 3...traveling hydraulic motor (hydraulic actuator), 4...swinging hydraulic motor (hydraulic actuator), 5...boom cylinder (hydraulic actuator), 6...arm cylinder (hydraulic actuator), 7...bucket cylinder (hydraulic actuator), 8...boom, 9...arm, 10...bucket (working tool), 11...lower traveling body, 12...upper rotating body, 13...bucket link, 18...engine, 20...control valve, 30...boom angle sensor, 31...arm angle sensor, 32...bucket angle sensor, 33...vehicle body inclination angle sensor, 36...vehicle body position detection device, 40...control device, 43...position and posture calculation unit, 44...electromagnetic proportional valve control unit, 50...working device posture detection device, 54-59...electromagnetic proportional valve, 81...actuator control unit, 90...motion planning unit, 91...automatic motion control unit, 92...trajectory deviation determination unit, 93...time deviation determination unit, 100...first input unit, 101...second input unit, 102...third input unit, 103...excavation surface inclination setting unit, 110...first output unit, 111...second output unit, 200...external connection device, P1...excavation start position, P2...maximum excavation depth position (mid-excavation position), P3...excavation end position, P4...motion end position, R...planned motion trajectory (target trajectory), S1...excavation start state, S2...maximum excavation depth state, S3...excavation end state, S4...motion end state.

Claims

1. A working device having a working tool; A hydraulic actuator that drives the working device; A hydraulic pump; a control valve for controlling a flow rate of pressure oil supplied from the hydraulic pump to the hydraulic actuator; a control device that calculates a target trajectory of a control point on the work implement and controls the control valve so that the control point moves along the target trajectory, The control device includes: Calculating a target trajectory that passes through an excavation start position where the control point is located at the start of excavation, an excavation mid-point position where the control point is located during excavation, and an excavation end position where the control point is located at the end of excavation, based on inclination information of the excavation surface, and a target attitude of the work tool when the control point moves on the target trajectory; The control valve is controlled so that the control point moves along the target trajectory and so that the attitude of the work tool when the control point moves along the target trajectory coincides with the target attitude. A working machine characterized by:

2. 2. The work machine according to claim 1, The mid-digging position is a maximum digging depth position located deepest from the ground surface on the target trajectory. A working machine characterized by:

3. 3. The work machine according to claim 2, The control device calculates the target trajectory so as to pass through an operation end position where the control point is located when the excavation operation is ended, in addition to the excavation start position, the maximum excavation depth position, and the excavation end position. A working machine characterized by:

4. 4. The work machine according to claim 3, The control device calculates the target posture at the operation end position based on the direction of gravity, regardless of the inclination of the excavation surface as the inclination information of the excavation surface. A working machine characterized by:

5. 3. The work machine according to claim 2, An external connection device is provided for inputting the inclination of the excavation surface to the control device as the inclination information of the excavation surface, The control device sets the excavation start position, the maximum excavation depth position, and the excavation end position according to an inclination of the excavation surface. A working machine characterized by:

6. 6. The working machine according to claim 5, The control device calculates the target attitude at the excavation start position, the target attitude at the maximum excavation depth position, and the target attitude at the excavation end position according to an inclination of the excavation surface. A working machine characterized by:

7. 6. The working machine according to claim 5, The control device includes: The smaller the downward slope of the excavation surface is, or the larger the upward slope of the excavation surface is, the closer the maximum excavation depth position is to the excavation start position, The smaller the upward inclination of the excavation surface, or the larger the downward inclination of the excavation surface, the closer the maximum excavation depth position is to the excavation end position; The smaller the downward slope of the excavation surface is, or the larger the upward slope of the excavation surface is, the shallower the maximum excavation depth position is set from the ground surface; The smaller the upward inclination of the excavation surface, or the larger the downward inclination of the excavation surface, the deeper the maximum excavation depth position is set from the ground surface. A working machine characterized by:

8. 6. The working machine according to claim 5, The control device sets the excavation start position and the excavation end position so that the distance from the excavation start position to the excavation end position becomes shorter as the upward slope of the excavation surface becomes smaller or the downward slope of the excavation surface becomes larger. A working machine characterized by:

9. 3. The work machine according to claim 2, An external connection device is provided for inputting the hardness of an object to be excavated into the control device, The control device sets the maximum excavation depth position according to the hardness of the excavation target. A working machine characterized by:

10. 10. The work machine according to claim 9, The control device calculates the target posture at the excavation start position, the target posture at the maximum excavation depth position, and the target posture at the excavation end position according to the hardness of the excavation object. A working machine characterized by:

11. 10. The work machine according to claim 9, The control device calculates the target attitude such that the orientation of the bottom surface of the work tool approaches the orientation of a tangent to the target trajectory as the hardness of the excavation target increases. A working machine characterized by:

12. 10. The work machine according to claim 9, The external connection device inputs the inclination of the excavation surface to the control device, The control device includes: The smaller the downward slope of the excavation surface is, or the larger the upward slope of the excavation surface is, the closer the maximum excavation depth position is to the excavation start position, The smaller the upward inclination of the excavation surface, or the larger the downward inclination of the excavation surface, the closer the maximum excavation depth position is to the excavation end position; The harder the object to be excavated is, the shallower the maximum excavation depth position is set from the ground surface; The lower the hardness of the excavation object, the deeper the maximum excavation depth position is set from the ground surface; The smaller the downward slope of the excavation surface is, or the larger the upward slope of the excavation surface is, the shallower the maximum excavation depth position is set from the ground surface; The smaller the upward inclination of the excavation surface, or the larger the downward inclination of the excavation surface, the deeper the maximum excavation depth position is set from the ground surface. A working machine characterized by:

Images