Work machine

Abstract

In an automatic work machine for planning and executing an operation in advance, it may be difficult to achieve a target soil amount for excavation and loading work. Therefore, provided is a work machine provided with a work device, the work machine comprising a control device capable of planning an excavation route where the target soil amount can be excavated regardless of terrain. On the basis of the target soil amount, the terrain information, and the maximum soil amount constraint corresponding to a ground angle of the work device, a target excavation route including the ground angle of a bucket 10 is planned, and the operation of the work device (bucket 10) including the ground angle of the bucket 10 is controlled so as to follow the target excavation route.

Description

Work machinery

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

[0002] BACKGROUND ART There has been proposed a work machine such as a hydraulic excavator that plans its operations in advance and automatically performs work in accordance with the planned operations.

[0003] For example, Patent Document 1 proposes a control device that plans a target path for a work implement (hereinafter also referred to as a work device or bucket) equipped on a work machine according to a predetermined excavation curve ratio, and controls the work implement along that target path.

[0004] Patent No. 7088792

[0005] According to Patent Document 1, an excavation path for a work implement provided on a work machine can be generated and control can be performed along that excavation path.

[0006] However, in general, for work machines such as hydraulic excavators, the terrain to be excavated varies depending on the application, and is not limited to flat ground as in Patent Document 1. Furthermore, in excavation and loading work, in order to load the right amount of earth and sand onto a transport vehicle such as a dump truck, it is necessary to excavate a desired amount of earth when carrying out excavation. When excavating a desired amount of earth on such terrain that is not flat, it is difficult to excavate the desired amount of earth simply by following a predetermined excavation path as in Patent Document 1.

[0007] The present invention has been made in consideration of the above, and aims to provide a work machine equipped with a control device that can plan an excavation path that can excavate a target amount of soil regardless of the terrain, in a work machine equipped with a work implement.

[0008] In order to solve the above problems, the work machine of the present invention is a work machine comprising a work implement including a bucket and a control device that controls the excavation operation of the work implement, and is characterized in that the control device comprises a target path planning calculation unit that plans a target excavation path that represents the target attitude of the work implement, including the ground angle of the bucket, in time series based on a predetermined target excavation volume, topographical information of the excavation range by the work implement, and a maximum excavation volume constraint for the ground angle of the bucket, and a target path following unit that controls the operation of the work implement, including the ground angle of the bucket, so as to follow the target excavation path.

[0009] According to the present invention, it is possible to plan an excavation route that can excavate a target amount of soil regardless of the terrain.

[0010] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments.

[0011] 1 is a perspective view of a hydraulic excavator equipped with a control system including a control device (controller) of the present invention. FIG. 1 is a system diagram of a control system according to a first embodiment of the present invention. FIG. 2 is a flowchart of a repose angle calculation unit, a maximum soil volume constraint calculation unit, and a target path planning calculation unit of the controller according to the first embodiment of the present invention. FIG. 3 is an example of a table storing repose angles in the repose angle calculation unit. FIG. 4 is an example of a geometric shape of a working implement. FIG. 5 is an example of a relationship between the geometric shape of the working implement and a maximum soil volume constraint due to the repose angle. FIG. 6 is a graph showing an example of a relationship between the absolute angle of the working implement and a maximum soil volume constraint. FIG. 7 is a system diagram of a hydraulic system (hydraulic circuit) according to the first embodiment of the present invention. FIG. 8 is an example of an internal block diagram of a target path tracking unit of the controller according to the first embodiment of the present invention (when configured with only feedforward). FIG. 9 is an example of a flowchart of the target path tracking unit of the controller according to the first embodiment of the present invention (when configured with only feedforward). FIG. 10 is an example of a target angle extracted by the plan extraction unit. FIG. 11 is an example of a coefficient of the actuator speed calculation unit. FIG. 12 is an example of an internal block diagram of the target path tracking unit of the controller according to the first embodiment of the present invention (when feedback is used). 1 is a diagram illustrating an example of a flowchart of a target path tracking unit of a controller according to a first embodiment of the present invention (when feedback is used); FIG. 2 is a diagram illustrating a specific example of a target angle extracted by a plan extraction unit; FIG. 3 is a diagram illustrating an example of a control system according to a second embodiment of the present invention; FIG. 4 is a graph illustrating an example of a relationship between an absolute angle of a work implement and a maximum soil volume constraint according to a second embodiment of the present invention; and FIG. 5 is a diagram comparing the operations and effects of the first embodiment and the second embodiment.

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, parts having the same function are designated by the same reference numerals, and repeated description may be omitted.

[0013] Although the embodiment of the present invention is described with reference to a backhoe-type shovel, it is applicable to all work machines that can move earth and sand with a work implement including a bucket, specifically, all shovels such as loading-type shovels, two-piece shovels, and offset shovels, as well as wheel loaders and skid steer loaders.

[0014] [Embodiment 1] <Overall Configuration> Fig. 1 is a perspective view of a hydraulic excavator 1 equipped with a control system including a control device (controller) of the present invention.

[0015] The hydraulic excavator (hereinafter simply referred to as "excavator") 1 includes a lower traveling body 1C, an upper rotating body 1B rotatably attached to the lower traveling body 1C via a swing device 4, and an articulated front end 1A attached to the upper rotating body 1B. The front end 1A includes a boom 8 rotatably attached to the upper rotating body 1B, an arm 9 rotatably attached to the boom 8, a bucket 10 rotatably attached to the arm 9, a bucket link 13 rotatably attached to the bucket 10 and the arm 9, a boom cylinder 5 connected to the boom 8 and the upper rotating body 1B and changing the rotation angle of the boom 8 and the upper rotating body 1B, an arm cylinder 6 connected to the boom 8 and the arm 9 and changing the rotation angle of the boom 8 and the arm 9, and a bucket cylinder 7 connected to the arm 9 and the bucket link 13 and changing the rotation angle of the bucket 10 via the bucket link 13. The lower traveling structure 1C is equipped with a crawler mechanism driven by a traveling motor 3, enabling the vehicle body to move. The turning device 4 is composed of a turning motor 11 that changes the turning angle of the lower traveling structure 1C and the upper rotating structure 1B. A controller 20 equipped with the control system of the present invention and an input device 25 are provided on the upper rotating structure 1B.

[0016] The control system of the present invention may be configured via wireless communication or the like as long as it can calculate the excavation path, and all components do not need to be mounted on the vehicle body. For example, instead of the controller 20 and input device 25, a communication terminal may be provided on the work machine (shovel 1), and the control system, its calculation device, and input device may be located externally.

[0017] The shovel 1 has a boom angle measuring device 21a provided on the boom 8 and measuring the relative rotation angle between the upper rotating body 1B and the boom 8, an arm angle measuring device 21b provided on the arm 9 and measuring the relative rotation angle between the boom 8 and the arm 9, and a bucket angle measuring device 21c provided on the bucket 10 and measuring the rotation angle between the arm 9 and the bucket 10.

[0018] Note that the angle / angular velocity measuring device is assumed to be an angle sensor and is described as an angle measuring device, but the form is not important as long as the relative angle can be measured and calculated, and the relative angle may be calculated based on the ground angle measured by an IMU (Inertial Measurement Unit) or the like.

[0019] The shovel 1 also has a topography measuring device 22 that is provided on the upper rotating body 1B and is capable of measuring the topography of the area excavated by the bucket 10.

[0020] In consideration of blind spots caused by the front 1A, a plurality of topographical measuring devices 22 may be provided.

[0021] Furthermore, the topography measuring device 22 may be any device capable of measuring the surface shape of the topography, such as a Lidar or a stereo camera.

[0022] <Configuration of Controller 20> FIG. 2 is a system diagram of a control system installed in the controller 20 of this embodiment.

[0023] The control system includes, as input devices 25, a target earth volume input unit 201 for inputting the target earth volume, a geometric shape input unit 203 for inputting the geometric shape (geometric information) of the bucket 10 as the work implement, and an excavation target input unit 204 for inputting the type of object to be excavated, and data is input from these input devices 25. Note that the work implement geometric shape input unit 203 and the excavation target input unit 204 may be configured to input specific numerical values ​​directly or to select from a list created in advance. Examples of the geometric shapes of the work implement will be described later.

[0024] The control system includes in the controller 20 a repose angle calculation unit 205 that calculates a repose angle based on information about the object to be excavated; a maximum soil volume constraint calculation unit 206 that calculates a constraint on the maximum soil volume that can be loaded onto the bucket 10 based on the repose angle and the geometric shape of the bucket 10; a mechanism information recording unit 208 that records mechanism information such as the lengths of the boom 8 and arm 9; a target path planning calculation unit 207 that plans target paths for the boom 8, arm 9, and bucket 10 of the work device based on the target soil volume, the shape of the terrain measured by the terrain measuring device 22, the maximum soil volume constraint, the geometric shape of the work device, and mechanism information; and a target path following unit 209 that calculates solenoid valve commands to solenoid valves 62, 63, 64 ( FIG. 11 ) to control the boom 8, arm 9, and bucket 10 so as to follow the target path planned by the target path planning calculation unit 207.

[0025] <Operation of Controller 20> FIG. 3 is a flowchart of the repose angle calculation unit 205, the maximum soil volume constraint calculation unit 206, and the target path planning calculation unit 207 of the controller 20 of this embodiment.

[0026] First, after the system starts, it is determined whether the excavation object has been changed (S301). If the excavation object has been changed, a repose angle is calculated based on the input information about the excavation object (S302) (repose angle calculation unit 205). On the other hand, if the excavation object has not been changed, it is determined whether the bucket 10 has been changed (S303). If the bucket 10 has been changed and after the processing of S302 (calculating the repose angle), a maximum soil volume constraint is calculated based on the geometric shape and repose angle of the changed bucket 10 (S304) (maximum soil volume constraint calculation unit 206). On the other hand, if the bucket 10 has not been changed and after the processing of S304 (calculating the maximum soil volume constraint), a target route is calculated based on the target soil volume and maximum soil volume constraint (S305), and the calculated target route is output (S306) (target route plan calculation unit 207).

[0027] <<Method of Calculating Repose Angle (Operation of Repose Angle Calculation Unit 205)>> A method of calculating the repose angle based on the information on the excavation target input in S302 will be described.

[0028] There are several possible methods for determining the repose angle from an excavation object, such as creating a table in advance that stores the repose angle corresponding to the type of excavation object, as shown in Figure 4, or manually or automatically dropping the excavation object from a bucket before path planning to form a mound, measuring the inclination angle of the mound, and determining the repose angle.

[0029] <<Method of Calculating Maximum Soil Volume Constraint (Operation of Maximum Soil Volume Constraint Calculation Unit 206)>> A method of calculating the maximum soil volume constraint based on the geometric shape and repose angle of the bucket 10 in S304 will be described.

[0030] The calculation method in this embodiment is merely an example, and any method may be used as long as it can calculate the maximum soil volume constraint based on the geometric shape.

[0031] Figure 5 shows the geometric information of the bucket 10. The geometric information of the bucket 10 is made up of multiple points on the bucket 10, multiple lines connecting the points, and surfaces enclosed by the multiple lines, and is approximated by a rectangular prism that contains the shape of the bucket 10. As shown in Figure 5, the vertices of the rectangular prism that is the geometric shape of the bucket 10 are called Pos. 1 to 4 and 5 to 8 counterclockwise from the corner near the toe position, and the sides are called Sides. 1 to 4 and 5 to 8.

[0032] In this embodiment, the geometric information is approximated by a quadrangular prism, but in consideration of the calculation speed, any curved shape such as a polygonal prism, or mesh data, etc. may be used, and the calculation method described below may be appropriately changed.

[0033] FIG. 6 is a schematic diagram of an example of the relationship between the geometric shape of the bucket 10 and the maximum soil volume constraint due to the repose angle φ, and FIG. 7 is a schematic diagram of the relationship between the geometric shape of the bucket 10 and the maximum soil volume constraint due to the repose angle θ of the bucket 10. bk and the maximum volume constraint V max 10 shows a graph of an example of the relationship between

[0034] Based on the geometric information in FIG. 5, FIG. 7 can be expressed as Equation 1. [Equation 1]

[0035] As shown in Figs. 6 and 7, the maximum soil volume constraint V max is determined based on the geometric shape of the bucket 10 and the repose angle φ, and the absolute angle (angle relative to the ground) θ bk It will be based on the following.

[0036] <<Method for Optimizing a Target Path (Operation of the Target Path Planning Calculation Unit 207)>> The optimization of the target path and the maximum earthwork volume constraint in S305 will be described.

[0037] Hereinafter, in this embodiment, the path plan or target path refers to a data format in which the progress rate t (0 to 1) of the excavation operation and the relative angles of the boom 8, arm 9, and bucket 10 are arranged in chronological order (see Figure 8).

[0038] FIG. 9 shows a flowchart of the method for optimizing the target path in S305, that is, a flowchart of the target path planning calculation unit 207 of the controller 20 of this embodiment.

[0039] The optimization method in S305 may be any method that optimizes the path relative to the relative angles of the boom 8, arm 9, and bucket 10. For example, the optimization parameters can be determined as shown in Equations 2 to 4 (S701, S702).

[0040] The relative angle θ of the boom 8, arm 9, and bucket 10 determined by equations 2 to 4 bm_t , θ am_t , θ bk_t A loop calculation is performed for the progress rate t (S703). The number of loops is determined appropriately based on the calculation speed and accuracy of the computer within the range of the progress rate t.

[0041] First, according to equations 2 to 4, the relative angle θ of the boom 8, arm 9, and bucket 10 at the current progress rate t is calculated. bm_t , θ am_t , θ bk_t is calculated (S704).

[0042] Next, as shown in Equation 5, the geometric information of the bucket 10 (coordinates P 1～8 ) and the relative angle θ bm_t , θ am_t , θ bk_t Based on this, the position P of the geometric information of bucket 10 at the current progress rate t i ' is calculated (S705). [Equation 3] T in Equation 5 is a coordinate transformation matrix (a forward kinematics transformation, such as a homogeneous transformation matrix) determined from the geometric arrangement of the boom 8, arm 9, and bucket 10 and the joint directions.

[0043] Next, P i The volume of the excavated volume V at the progress rate t is calculated by the overlapping volume (Boolean product operation) of the solid composed of ' and the terrain shape at the previous progress rate. dig_t On the other hand, from the topographical shape of the previous progress rate, P i The shape (calculated by Boolean difference) excluding the solid (overlapping portion of the geometric information of the bucket 10) formed by the lines ' is set as the topographical shape at the progress rate t (S707).

[0044] The above steps S704 to S707 are repeated for the progress rate t in the range of 0 to 1 (S708 to S710).

[0045] After the repetition based on the progress rate t is completed, an evaluation is performed based on the volume after excavation completion and the maximum soil volume constraint (S711). The evaluation value J is calculated using predetermined arbitrary weights ω1 and ω2, the evaluation value J1 related to the volume after excavation completion, and the evaluation value J2 based on the maximum soil volume constraint (Equation 6). [Equation 4]

[0046] The evaluation value J1 based on the volume after the excavation is calculated based on the target excavation volume V digtarget and the excavated volume V dig_t The calculation is performed using (Equation 7). [Equation 5]

[0047] On the other hand, the evaluation value J2 due to the maximum soil volume constraint is evaluated based on whether the progress rate t exceeds each constraint condition (Equation 8, Equation 9). [Equation 6] However, when the right side of Equation 9 is 0 or less, j 2_t =0 (so-called saturation processing).

[0048] Finally, the target route after the optimization calculation reaches the target earth volume at t=1, as shown in FIG. 10, and is equal to or less than the curve of the maximum earth volume constraint in all sections of t.

[0049] However, the target soil volume input in the target soil volume input unit 201 is the maximum soil volume V among all the angles of the bucket 10 calculated in the maximum soil volume constraint calculation unit 206. max_max (Maximum soil volume V max_max 7), the controller 20 notifies the operator or the like that the input target soil volume cannot be achieved, or uses V digtarget =V max_max Then, the following calculations (for example, Equation 7) are performed.

[0050] Next, the target path tracking unit 209 of the controller 20 of this embodiment will be described with reference to FIGS.

[0051] FIG. 11 is a system diagram of a hydraulic system (hydraulic circuit) which is a means for realizing the target flow rate in this embodiment (downstream actuator control means in FIG. 2).

[0052] The hydraulic system 50 comprises a tank 52 for storing hydraulic oil, a pump 51 driven by a prime mover (not shown) such as an engine to pressurize the hydraulic oil in the tank 52 and supply pressure oil to the hydraulic system 50, a regulator 57 for controlling the discharge flow rate of the pump 51, a relief valve 53 connected between the pump 51 and the tank 52 and limiting the maximum value of the supply pressure, a spool valve 54 for controlling the supply and discharge of pressure oil to the boom cylinder 5 in accordance with the pilot pressure received at pressure receiving sections A1 and A2, and a pressure receiving section 55 for controlling the supply and discharge of pressure oil to the arm cylinder 6 in accordance with the pilot pressure received at pressure receiving sections B1 and B2. a spool valve 55 that controls the supply and discharge of pressure oil to and from the bucket cylinder 7 in accordance with the pilot pressure received by pressure receiving portions C1 and C2; a pilot pump 61 that is driven by a prime mover such as an engine (not shown) and supplies pilot pressure oil; and solenoid valves 62, 63, and 64 (also see FIG. 2 ) that reduce the pressure of the pilot pressure oil in accordance with a command (solenoid valve command) from the controller 20 and generate pilot pressures that act on the pressure receiving portions (A1, A2), (B1, B2), and (C1, C2) of the spool valves 54, 55, and 56.

[0053] The spool valves 54, 55, and 56 can control the flow rate and direction of the pressurized oil supplied to the boom cylinder 5, arm cylinder 6, and bucket cylinder 7, which are actuators, in accordance with the pilot pressure controlled by the controller 20, thereby controlling the operation of the boom 8, arm 9, and bucket 10.

[0054] In this embodiment, the operating speed and direction of the actuator are controlled by controlling the pilot pressure, but any form may be used as long as the operating speed and direction of the actuator can be controlled by commands from the controller 20, such as the spool valves 54, 55, and 56 themselves being solenoid valves controlled by commands from the controller 20, or the actuators (partly or entirely) being electrically powered.

[0055] <<Configuration using only feedforward>> Fig. 12 is an example of an internal block diagram of the target path tracking unit 209 in Fig. 2. The target path tracking unit 209 is composed of a plan extraction unit 1001, an angular velocity calculation unit 1002, an actuator velocity calculation unit 1003, a flow rate calculation unit 1004, and a solenoid valve operation unit 1005. Fig. 13 is a flowchart of the internal block diagram in Fig. 12.

[0056] After the target path planning calculation unit 207 completes the path planning, the target path tracking unit 209 sets the progress rate t to 0 and starts path tracking (S1101).

[0057] The target path tracking unit 209 calculates the update amount Δt of the progress rate based on the calculation period (calculation time) Δn of the controller and a predetermined k (S1102) (plan extraction unit 1001), and sequentially updates the progress rate t of the path plan for each controller period (S1108, S1109, S1110).

[0058] The value k used in the calculation in S1102 may be any value as long as the actuator speed does not exceed a predetermined maximum value in the actuator speed calculation unit 1003 at the subsequent stage.

[0059] The target path tracking unit 209 calculates a target angle θ of the current progress rate t based on the target path planned by the target path planning calculation unit 207. act_t and the next target angle θact_t+Δt (S1103) (plan extraction unit 1001) (specific example: see FIG. 14).

[0060] The target path tracking unit 209 calculates a target cylinder flow rate based on these target angles, mechanism design values, cylinder design values, etc. (S1104, S1105, S1106) (angular velocity calculation unit 1002, actuator velocity calculation unit 1003, flow rate calculation unit 1004) (also see FIG. 15 ), and calculates a command (solenoid valve command) to the solenoid valves 62, 63, 64 based on the target cylinder flow rate (S1107) (solenoid valve operation unit 1005).

[0061] When the target path tracking unit 209 determines that the plan has reached the end (t=1) (S1108), it determines that excavation is complete and stops the path tracking operation (S1111).

[0062] <<When Feedback is Used>> Fig. 16 is another example of an internal block diagram of the target path tracking unit 209 in Fig. 2. The target path tracking unit 209 is composed of a plan extraction unit 1401, an angular velocity calculation unit 1402, an actuator velocity calculation unit 1403, a flow rate calculation unit 1404, and a solenoid valve operation unit 1405. Fig. 17 is a flowchart of the internal block diagram in Fig. 16. Note that in this case, an angle measurement device 21 consisting of a boom angle measurement device 21a, an arm angle measurement device 21b, and a bucket angle measurement device 21c is required.

[0063] After the route planning is completed, the target route tracking unit 209 sets the progress rate t to 0 and starts route tracking (S1501).

[0064] The target path tracking unit 209 calculates the current angle θ obtained from the angle measurement device 21 in the plan extraction unit 1401. act_sens Based on this, the target angle θ act_t are calculated (S1502, S1503).

[0065] Any method for calculating the target angle can be used as long as it is uniquely determined based on the current angle. For example, one method is to use the progress rate corresponding to the angle closest to the current angle in the route plan as the current progress rate t, and then use a plan that is a predetermined Δt2 ahead of that t (see Figure 18).

[0066] The angular velocity calculation unit 1402, actuator velocity calculation unit 1403, flow rate calculation unit 1404, and solenoid valve operation unit 1405 in FIG. 16, and S1504 to S1511 in FIG. 17 are similar to the angular velocity calculation unit 1002, actuator velocity calculation unit 1003, flow rate calculation unit 1004, and solenoid valve operation unit 1005 in FIG. 12, and S1104 to S1111 in FIG. 13, and therefore description thereof will be omitted.

[0067] Feedback allows for the correction of deviations from the plan during execution, resulting in more accurate tracking of the plan than would be possible with feedforward alone.

[0068] <Effects specific to this embodiment> According to this embodiment 1, by planning the excavation path so that the volume of soil excavated by the bucket 10 is always below the maximum soil volume constraint during excavation and ultimately reaches the target soil volume, soil will not spill out of the bucket 10 and it will be possible to excavate the target soil volume even on terrain that is not flat.

[0069] [Example 2] An operation that causes all the soil and sand to spill out of the bucket is an operation that merely moves the soil and sand. For example, this is an excavation operation in which the opening of the bucket is facing almost directly downward. In this case, the bucket passing volume ≒ soil volume in the bucket, which is assumed in the excavation path plan of Example 1, no longer holds true.

[0070] In the case of Example 1, the amount of soil in the bucket is always kept below the maximum soil volume constraint during excavation, but during actual excavation, even if the maximum soil volume constraint is exceeded to some extent due to the influence of soil and sand, the speed of the bucket itself, inertia, etc., the soil will not spill out of the bucket. Naturally, the soil will spill out when the bucket is stopped.

[0071] In Example 1, this point is not taken into consideration, so the degree of freedom in route selection is limited. As a solution to this, in Example 2, "a certain amount of play" is added to the curve of the maximum soil volume constraint, thereby expanding the degree of freedom in route selection.

[0072] <Overall Configuration> The hardware configuration of the second embodiment is the same as that of the first embodiment.

[0073] <Configuration of Controller 20> FIG. 19 is a system diagram of a control system mounted on the controller 20 of this embodiment.

[0074] In addition to the configuration of Example 1, the control system is equipped with a soil volume margin input unit 801 that can input soil volume margin using the input device 25 or the like, and is equipped with a maximum soil volume constraint calculation unit with margin 802 that calculates the maximum soil volume constraint based on the soil volume margin, repose angle, and the geometric shape of the work equipment, instead of the maximum soil volume constraint calculation unit 206.

[0075] <Operation of the controller 20> In the maximum soil volume constraint calculation unit 802, V in Equation 1 max The excavation volume margin V input in the soil volume margin input section 801 margin Add the maximum soil volume constraint V' with margin. max (Equation 10). bk and the maximum volume constraint V' with margin max The relationship between the above equations is shown in [Equation 7].

[0076] As in the first embodiment, the maximum earth volume constraint with margin V' calculated by the maximum earth volume constraint with margin calculation unit 802 max Based on this, the target path planning calculation unit 207 plans the target path.

[0077] In addition, V max The soil volume margin to be added is the absolute angle θ of the bucket 10 bk , or the absolute angle θ of the bucket 10 bk For example, the absolute angle θ of the bucket 10 may be variable depending on the bk The smaller the size, the larger the soil volume allowance can be.

[0078] <Effects specific to the form> According to this embodiment 2, instead of the effect of the embodiment 1, the trade-off relationship between the spill amount and the degree of freedom of route selection can be adjusted by adjusting the angle margin, so it is possible to provide a system that can adjust the accuracy and the degree of freedom of route. The difference between the embodiment 1 and the embodiment 2 is shown in Figure 21. In the embodiment 1, as in Equation 1, the maximum soil volume constraint V is maintained until the line segment extended in the φ direction from Pos.1 coincides with Side.1. maxdoes not become greater than 0, and excavation is not performed. In other words, for a specific starting posture and terrain, excavation is not performed until halfway, and the bucket tip moves along the ground surface. In contrast, in the case of Example 2, even if the line segment extended in the φ direction from Pos.1 does not coincide with Side.1, the maximum soil volume constraint with margin V' max is greater than 0, so digging is possible. That is, even for a specific starting attitude and terrain, digging can be performed from the start of path following.

[0079] [Summary] As described above, the work machine (hydraulic excavator 1) of this embodiment is equipped with a work implement including the bucket 10 and a control device (controller 20) that controls the excavation operation of the work implement, and the control device (controller 20) is equipped with a target path planning calculation unit 207 that plans a target excavation path that represents, in time series, target attitudes of the work implement, including the ground angle of the bucket 10 (for continuing the excavation operation of the work implement), based on a preset target excavation volume (target soil volume), topographic information of the area excavated by the work implement (bucket 10), and a maximum excavation volume constraint (maximum soil volume constraint) on the ground angle of the bucket 10, and a target path following unit 209 that controls the operation of the work implement, including the ground angle of the bucket 10, so as to follow the target excavation path (so as to operate along the target path). The target path planning calculation unit 207 inputs topographic information of the area excavated by the work implement (bucket 10), which is measured by a topography measuring device 22 (during the excavation operation of the work implement).

[0080] According to this embodiment, it is possible to plan an excavation route that enables a target amount of soil to be excavated regardless of the terrain.

[0081] The target path planning calculation unit 207 determines the maximum excavation amount constraint (maximum soil volume constraint) based on the geometric shape of the bucket 10 .

[0082] According to this embodiment, an excavation path can be planned even if the shape of the bucket 10 changes.

[0083] The target path planning calculation unit 207 determines the maximum excavation volume constraint (maximum soil volume constraint) based on information about the excavation object (the type and properties of the object that affect the repose angle).

[0084] According to this embodiment, an excavation route can be planned even if the excavation object changes.

[0085] The target path planning calculation unit 207 receives information about the excavation target from the input device 25 (excavation target input unit 204).

[0086] According to this embodiment, any excavation target can be designated.

[0087] The target path planning calculation unit 207 plans the target excavation path based on a maximum excavation volume constraint (maximum soil volume constraint) with a margin, which is the maximum excavation volume constraint (maximum soil volume constraint) plus an excavation volume margin (soil volume margin). The target path planning calculation unit 207 sets the excavation volume margin (soil volume margin) in accordance with the ground angle of the bucket 10.

[0088] According to this embodiment, the accuracy and flexibility of the route can be adjusted.

[0089] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0090] Furthermore, the functions of the controller in the above-described embodiments may be implemented in hardware, for example, by designing some or all of them as integrated circuits. Alternatively, the functions may be implemented in software, with a processor interpreting and executing a program that implements each function. Information such as the programs, tables, and files that implement each function may be stored in a storage device within the controller, a hard disk, a solid-state drive (SSD), or a recording medium such as an IC card, an SD card, or a DVD.

[0091] REFERENCE SIGNS LIST 1 Hydraulic excavator (working machine) 1A Front (working device) 1B Upper rotating body 1C Lower traveling body 3 Traveling motor 4 Swing device 5 Boom cylinder 6 Arm cylinder 7 Bucket cylinder 8 Boom 9 Arm 10 Bucket 11 Swing motor 13 Bucket link 20 Controller (control device) 21 Angle measuring device 22 Topography measuring device 25 Input device

Claims

1. A work machine comprising a working implement including a bucket and a control device that controls the excavation operation of the working implement, wherein the control device comprises: a target path planning calculation unit that plans a target excavation path that represents a target attitude of the working implement including the ground angle of the bucket in a time series based on a predetermined target excavation volume, topographical information of the excavation range by the working implement, and a maximum excavation volume constraint for the ground angle of the bucket; and a target path following unit that controls the operation of the working implement including the ground angle of the bucket so as to follow the target excavation path.

2. A work machine as claimed in claim 1, characterized in that the target path planning calculation unit inputs topographical information of the excavation range to be excavated by the work implement, the topographical information being measured by a topographical measuring device.

3. A work machine according to claim 1, characterized in that the target path planning calculation unit determines the maximum excavation volume constraint based on the geometric shape of the bucket.

4. A work machine according to claim 1, characterized in that the target path planning calculation unit determines the maximum excavation volume constraint based on information about the object to be excavated.

5. A work machine according to claim 4, characterized in that the target path planning calculation unit inputs information about the object to be excavated from an input device.

6. A work machine as claimed in claim 1, characterized in that the target path planning calculation unit plans the target excavation path based on a maximum excavation volume constraint with a margin, which is obtained by adding an excavation volume margin to the maximum excavation volume constraint.

7. A work machine according to claim 6, wherein the target path planning calculation unit sets the excavation volume margin in accordance with the ground angle of the bucket.

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