Control system for work machine

Abstract

Provided is a control system for a work machine, the control system being capable of continuously executing a digging operation without performing incomplete digging or interrupting work in automatic digging control of the work machine. A re-planning necessity determination unit (207) determines whether or not re-planning of the excavation trajectory is necessary during the vehicle body operation, and when the re-planning necessity determination unit (207) determines that re-planning is necessary, a re-planning unit (204) re-plans the excavation trajectory during the vehicle body operation.

Description

Technical Field

[0001] The present invention relates to a control system for a work machine that performs automatic excavation control. Background Art

[0002] In work machines such as hydraulic excavators, work machines that plan prior actions and automatically perform operations according to the planned actions have been proposed.

[0003] For example, in Patent Document 1, a control system is proposed that generates a target trajectory of a work machine according to a ratio of a preset excavation curve and performs control to output an operation signal of the work machine according to the target trajectory.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent No. 7088792 Gazette Summary of the Invention

[0007] According to Patent Document 1, it is possible to generate an excavation trajectory of a work machine and perform control according to the excavation trajectory (automatic excavation control).

[0008] However, in the excavation work performed by work machines such as hydraulic excavators, the sandy soil of the excavation target causes a change in the excavation load depending on the properties and state, and the state of the soil. Therefore, it often happens that the excavation cannot be performed according to the previously given excavation trajectory. As a result, incomplete excavation that cannot follow the excavation trajectory, interruption of work, etc. may occur.

[0009] The present invention has been made in view of the above circumstances, and an object thereof is to provide a control system for a work machine that can continuously execute an excavation action without incomplete excavation or interruption of work in the automatic excavation control of the work machine.

[0010] In order to solve the above problems, the control system of the working machine of the present invention controls the excavation operation of the working device in the excavation operation of the working machine equipped with the working device. The control system of the working machine is characterized in that it includes a controller, and the controller has: an excavation trajectory planning unit that plans the excavation trajectory of the working device based on the volume of the excavation object to be excavated set in advance; and a plan execution unit that controls the operation of the working device to achieve the excavation trajectory planned by the excavation trajectory planning unit. The excavation trajectory planning unit includes: an initial planning unit that plans the excavation trajectory before the working device operates; a re-planning necessity determination unit that determines whether it is necessary to re-plan the excavation trajectory according to the change of the progress rate of the operation of the working device based on the excavation trajectory planned by the initial planning unit with respect to time in order to continuously perform the excavation operation of the working device during the operation of the working device based on the excavation trajectory planned by the initial planning unit; and a re-planning unit that re-plans the excavation trajectory for continuously performing the excavation operation of the working device during the operation of the working device based on the excavation trajectory planned by the initial planning unit when it is determined by the re-planning necessity determination unit that re-planning is required.

[0011] Advantages of the Invention

[0012] According to the present invention, even if the excavation operation cannot be continued due to unforeseen factors during the excavation operation, the excavation trajectory can be re-planned, and the excavation operation can be continuously executed without incomplete excavation or interruption of the operation.

[0013] The problems, configurations, and effects other than the above can be clarified by the description of the following embodiments. Brief Description of the Drawings

[0014] Figure 1 is a perspective view of the hydraulic excavator 1 equipped with the control system of the present invention.

[0015] Figure 2 is a system diagram of the control system according to Embodiment 1 of the present invention.

[0016] Figure 3 is a flowchart of the re-planning unit 204 and the trajectory selection unit 205 according to Embodiment 1 of the present invention.

[0017] Figure 4 is a flowchart of the method for calculating the volume of soil according to Embodiment 1 of the present invention.

[0018] Figure 5 is in Figure 4 is an explanatory diagram of the volume calculated and excavated in S404.

[0019] Figure 6It is a flowchart of the replanning necessity determination unit 207 of Embodiment 1 of the present invention.

[0020] Figure 7 It is a flowchart of the progress management unit 208 of Embodiment 1 of the present invention.

[0021] Figure 8 It is a system diagram of the control system of Embodiment 2 of the present invention.

[0022] Figure 9 It is a flowchart of the deepest distance calculation unit 701 of Embodiment 2 of the present invention.

[0023] Figure 10 It is an explanatory diagram of the deepest distance.

[0024] Figure 11 It is a system diagram of the control system of Embodiment 3 of the present invention.

[0025] Figure 12 It is a flowchart of the replanning necessity determination unit 902 of Embodiment 3 of the present invention.

[0026] Figure 13 It is a system diagram of the control system of Embodiment 4 of the present invention.

[0027] Figure 14 It is an example of the display of the display device of Embodiment 4 of the present invention. Detailed Embodiments

[0028] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, parts having the same function may be denoted by the same reference numeral and repeated description may be omitted. It should be noted that, as an example, a hydraulic excavator 1 equipped with a control system of the present invention and having a bucket 10 as a working tool (attachment) at the front end of the working device is illustrated below, but the present invention can also be applied to a working machine equipped with an attachment other than the bucket. In addition, as long as it has a multi-joint type working device formed by connecting a plurality of link members (attachments, boom arms, booms, etc.), it can also be applied to a working machine other than a hydraulic excavator.

[0029] [Embodiment 1]

[0030] <Overall Configuration>

[0031] Figure 1 It is a perspective view of a hydraulic excavator 1 equipped with the control system of the present invention.

[0032] A hydraulic excavator (hereinafter simply referred to as an excavator) 1 includes a lower traveling body 1C, an upper revolving body 1B rotatably mounted on the lower traveling body 1C by means of a slewing device 4, and a front device 1A as a working device mounted on the upper revolving body 1B. The front device 1A is composed of a boom 8, an arm 9, a bucket 10, a bucket link 13, a boom cylinder 5, an arm cylinder 6, and a bucket cylinder 7. The boom 8 is rotatably mounted on the upper revolving body 1B, the arm 9 is rotatably mounted on the boom 8, the bucket 10 is rotatably mounted on the arm 9, the bucket link 13 is rotatably mounted on the bucket 10 and the arm 9. The boom cylinder 5 is connected to the boom 8 and the upper revolving body 1B and arbitrarily changes the rotation angle between the boom 8 and the upper revolving body 1B. The arm cylinder 6 is connected to the boom 8 and the arm 9 and arbitrarily changes the rotation angle between the boom 8 and the arm 9. The bucket cylinder 7 is connected to the arm 9 and the bucket link 13 and arbitrarily changes the rotation angle of the bucket 10 via the bucket link 13. The lower traveling body 1C is driven by a traveling motor 3 to move the vehicle body to an arbitrary position. The slewing device 4 is composed of a slewing motor 11 that arbitrarily changes the rotation angle between the lower traveling body 1C and the upper revolving body 1B. A controller 20 incorporating the control system of the present invention is provided on the upper revolving body 1B.

[0033] It should be noted that the control system of the present invention only needs to be able to calculate the excavation trajectory (also called the track), and it can also be via wireless communication or the like. That is to say, it does not need to be installed on the vehicle body. For example, the construction machine (excavator 1) is equipped with a communication terminal, and the control system can also be located in an external server or the like.

[0034] The excavator 1 includes: a boom angle measuring device 21a provided on the boom 8 for measuring the relative rotation angle between the upper revolving body 1B and the boom 8; an arm angle measuring device 21b provided on the arm 9 for 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 for measuring the rotation angle between the arm 9 and the bucket 10.

[0035] It should be noted that the angle / angular velocity measuring device is assumed to be an angle sensor. Although it is referred to as an angle measuring device, as long as it can measure / calculate the relative angle, the method is not limited, and the relative angle can also be calculated by subtracting the ground angle such as an IMU.

[0036] In addition, the excavator 1 has a terrain measuring device 22 provided on the upper revolving body 1B and capable of measuring the terrain of the excavation range of the bucket 10.

[0037] It should be noted that considering the dead angles caused by the front device 1A and the like, the terrain measuring device 22 may also have multiple units.

[0038] <Configuration of the controller 20>

[0039] Figure 2 It is a system diagram of the control system mounted in the controller 20 of this embodiment.

[0040] It should be noted that, in this embodiment, the control system is mounted in the controller 20 on the vehicle body, but as long as the configuration of this embodiment can be achieved, it can also be installed in a controller outside the vehicle body and controlled via communication.

[0041] The controller 20 equipped with the control system in this embodiment is composed of a digging trajectory planning unit 200 and a plan execution unit 201 in order to calculate the digging trajectory (also called the digging track) of the bucket 10 during the digging operation of the excavator 1 and control the digging action.

[0042] The digging trajectory planning unit 200 is a module as follows: Based on the volume of the excavation object to be excavated, such as sandy soil, which is preset, that is, in such a way that the bucket 10 excavates a preset volume of sandy soil, the digging trajectory of the bucket 10 is planned (in other words, the digging trajectory plan is calculated). The digging trajectory planning unit 200 includes an initial planning unit 202, a terrain shape calculation unit 203, a replanning unit 204, a trajectory selection unit 205, a working device geometry storage unit 206, and a replanning necessity judgment unit 207.

[0043] The initial planning unit 202 plans the digging trajectory of the bucket 10 (trajectory plan (initial)) before the start of the digging action (before the start of the action of the working device).

[0044] The terrain shape calculation unit 203 calculates the terrain shape before the start of the operation based on the measurement results of the terrain measurement device 22.

[0045] The terrain measurement device 22 only needs to be able to measure the terrain shape near the digging trajectory of the bucket 10, and there are, for example, lidar (Lidar), stereo cameras, etc.

[0046] In addition, if the excavation object is, for example, sandy soil, the calculation object of the terrain shape calculation unit (peripheral shape calculation unit) 203 is the terrain shape near the digging trajectory of the bucket 10 within the range where the sandy soil is located. If the excavation object is an artificial object such as industrial waste, the calculation object of the terrain shape calculation unit (peripheral shape calculation unit) 203 is the shape of the accumulation of industrial waste near the movement trajectory of the bucket 10 within the range where the industrial waste accumulates.

[0047] The terrain shape calculation unit 203 transforms the data of the terrain near a preset excavation site at any coordinate on the excavator 1 (for example, the coordinates with the rotation center of the upper slewing body 1B as the origin) based on the three-dimensional coordinate information output by the terrain survey device 22 and the geometric configuration of the terrain survey device 22. It should be noted that the terrain data can be a height map, voxels, etc., and can be any data as long as the height (z) on the plane (xy) can be known. In addition, the terrain near the excavation site specifically includes at least the working range of the front device 1A of the excavator 1.

[0048] The working device geometry storage unit 206 records (stores) the geometry (geometric information) of the bucket 10.

[0049] The replanning necessity determination unit 207 determines whether it is necessary to replan the excavation trajectory of the bucket 10 based on the relative angles output by the angle detection device 21 (boom angle measurement device 21a, arm angle measurement device 21b, bucket angle measurement device 21c) according to whether continuous excavation is possible. That is, the replanning necessity determination unit 207 of the present embodiment determines whether continuous excavation (whether the excavation operation stops) by determining the stop state of the actuators (boom hydraulic cylinder 5, arm hydraulic cylinder 6, bucket hydraulic cylinder 7) that move the bucket 10 based on the relative angles output by the angle detection device 21 during the excavation operation (during the operation of the working device), and determines whether it is necessary to replan the excavation trajectory of the bucket 10 in order to continuously perform the excavation operation of the bucket 10 (as described later). In other words, the replanning necessity determination unit 207 determines whether it is necessary to replan the excavation trajectory for continuously performing the excavation operation of the bucket 10 during the excavation operation (during the operation of the working device).

[0050] Based on the current excavation trajectory (current trajectory plan) output by the trajectory selection unit 205, the progress rate output by the progress management unit 208, the terrain shape output by the terrain shape calculation unit 203, the geometry of the bucket 10 output by the working device geometry storage unit 206, the relative angles output by the angle detection device 21, and the replanning necessity determination of the replanning necessity determination unit 207, when the replanning necessity determination unit 207 determines that replanning is necessary, the replanning unit 204 replans the excavation trajectory (trajectory plan (re)) for continuously performing the excavation operation of the bucket 10 during the excavation operation (during the operation of the working device). At this time, the replanning unit 204 replans an excavation trajectory (trajectory plan (re)) such as excavating a volume equal to the volume of the excavation object (such as sandy soil) expected to be excavated by the excavation trajectory (trajectory plan (initial)) planned by the initial planning unit 202 based on the above information.

[0051] The trajectory selection unit 205 outputs the current trajectory plan, which is the target of the work machine, based on the trajectory plan (initial) output by the initial planning unit 202, the trajectory plan (re - plan) output by the replanning unit 204, and the replanning necessity determination output by the replanning necessity determination unit 207.

[0052] The plan execution unit 201 is a module that controls the actions of the actuators (boom hydraulic cylinder 5, arm hydraulic cylinder 6, bucket hydraulic cylinder 7) that move the bucket 10 in such a way as to achieve the excavation trajectory plan (current trajectory plan) planned by the above - mentioned excavation trajectory planning unit 200. The plan execution unit 201 includes a progress management unit 208, a target value output unit 209, and an actuator control system 210.

[0053] The progress management unit 208 outputs the progress rate of the trajectory plan based on the current trajectory plan output by the trajectory selection unit 205 and the relative angle output by the angle detection device 21.

[0054] The target value output unit 209 outputs the current target angle based on the current trajectory plan output by the trajectory selection unit 205 and the progress rate output by the progress management unit 208.

[0055] The actuator control system 210 outputs commands to each device based on the target angle output by the target value output unit 209 so that the actuators (boom hydraulic cylinder 5, arm hydraulic cylinder 6, bucket hydraulic cylinder 7) perform appropriate actions.

[0056] It should be noted that the initial planning unit 202 and the replanning unit 204 may also have commonality by using the same trajectory generation algorithm. However, in the case of having commonality, it is necessary to output the volume of soil that is the target of the initial plan.

[0057] In this embodiment, the trajectory plan refers to a table of the progress rate (%) and the relative angles of the boom 8, arm 9, and bucket 10.

[0058] It should be noted that the trajectory plan only needs to uniquely determine the relative angles of the boom 8, arm 9, and bucket 10 and their time - series order. For example, it is also possible to mark the progress rate with time, construct an arithmetic formula for calculating the relative angle using a combination of positions and angles such as the tip position of the bucket 10 and the absolute angle of the bucket 10, the bucket pin position and the absolute angle of the bucket 10, and the progress rate.

[0059] <Actions of the controller 20>

[0060] Figure 3 It is a flowchart of the replanning unit 204 and the trajectory selection unit 205 of the controller 20 in this embodiment.

[0061] First, when the trajectory plan (initial) is completed by the initial planning unit 202, the trajectory plan (initial) is set as the current trajectory plan (S301). The current trajectory plan is realized by the target value output unit 209 and the actuator control system 210, and the need for replanning is judged by the replanning necessity judgment unit 207 to judge the replanning necessity state (S302). When the result judged in S302 is that replanning is not required, the current trajectory plan is continuously used (S308). On the other hand, when the result judged in S302 is that replanning is required, the volume of the remaining estimated excavated soil is calculated using the current excavation trajectory (current trajectory plan) and the progress rate (S303). It should be noted that in order to shorten the calculation time, the trajectory plan, the progress rate, and the volume of the estimated excavated soil may also be recorded in a memory or the like in advance at the trajectory plan creation time (for example, the initial planning unit 202, S304) and referred to.

[0062] After S303, search is performed by performing loop calculation or the like on a trajectory where the relative angle with the start position is the same as the volume of the remaining estimated excavated soil (S304). It is judged whether the calculation (replanning) in S304 is completed within a predetermined specified time (S305). When the calculation in S304 is not completed within the predetermined specified time, an error signal is issued to stop the operation of the vehicle body (S307). On the other hand, when the calculation converges, the trajectory calculated in S304 is set as the trajectory plan (replan) and updated to the current trajectory plan (S306).

[0063] 《Example of S304》

[0064] Regarding the trajectory generation method in S304, any method can be adopted as long as the volume of the estimated excavated soil is made consistent. For example, a method considering the following polynomial approximation can be considered. It should be noted that polynomial approximation is a well-known trajectory generation method for generating the fingertip trajectory of a robotic arm, so detailed description is omitted.

[0065]

Mathematical formula 1

[0066] θ bm =a bm t 5 +b bm t 4 +c bm t 3 +d bm t 2 +e bm t 1 +f bm t 0 Formula 1

[0067] θam = a am t 5 + b am t 4 + c am t 3 + d am t 2 + e am t 1 + f am t 0 Equation 2

[0068] θ bk = a bk t 5 + b bk t 4 + c bk t 3 + d bk t 2 + e bk t 1 + f bk t 0 Equation 3

[0069] θ: Relative angle

[0070] t: Progress rate (0 to 1)

[0071] a to e: Optimal variables

[0072] f: Current relative angle subscript of boom, stick, and bucket: bm = boom 8, am = stick 9, bk = bucket 10

[0073] In S304, search for the optimal variables (a to e) that minimize the following evaluation value J. Any search method can be adopted as long as it is a so-called optimization method.

[0074]

Mathematical formula 2

[0075]

[0076] F: Soil volume calculation function

[0077] V Dig : Remaining estimated volume of soil to be excavated

[0078] Map: Terrain shape

[0079] Mec: Geometric information

[0080] t now : Current progress rate (0 to 1)

[0081] Figure 4 is with respect to Figure 3Flowchart of the soil volume calculation method for S303 and S304. It should be noted that the optimization variables are assumed to be known.

[0082] First, substitute the current progress rate t now into the progress rate i for calculation (S401). To calculate the volume of soil from the current progress rate t now to the end of excavation (progress rate = 1), calculate the terrain change at discrete progress rates and accumulate it (loop based on the progress rate for calculation). In the loop, first, substitute the progress rate i for calculation into Equations 1 - 3 and calculate the current relative angles θ bm_i 、θ am_i 、θ bk_i (S402) of each joint.

[0083] Calculate the current position of the bucket geometry based on the relative angles obtained in S402 and the bucket geometry (S403).

[0084] It should be noted that the bucket geometry only needs to appropriately simulate the actual bucket. In this embodiment, for example, it is assumed to be mesh data configured in a way that includes the actual geometry of the bucket.

[0085] In addition, in S403, for example, if a certain point in the mesh data on the bucket is set as X, the point X' at the progress rate i for calculation is expressed by the following Equation 5.

[0086]

Mathematical Equation 3

[0087] X′ = T(θ bm_i )T(θ bm _ i + θ am_i )T(θ bm_i + θ am_i + θ bk_i )X Equation 6

[0088] It should be noted that T in Equation 5 refers to the coordinate transformation matrix (coordinate transformation based on forward kinematics), such as a homogeneous transformation matrix, etc.

[0089] By performing the same calculation for all points constituting the mesh, the current position of the bucket geometry based on any posture can be calculated.

[0090] Based on the current position of the bucket geometry calculated in S403 and the terrain shape, calculate the volume after excavating the overlapping solid based on the position and posture at the progress rate i for calculation, and the shape after removing the overlapping solid volume from the terrain shape is the new terrain shape (S404). For example, Figure 5Shows the volume of the overlapping solids at a certain calculation progress rate i and the volume of the overlapping solids in the next step of the calculation progress rate i. The specific calculation method of S404 is the so-called Brillouin operation. The algorithm of the Brillouin operation can be any algorithm.

[0091] Update the terrain shape calculated in S404 (S405), and accumulate the volume of excavation (S406). Determine whether the calculation progress rate i is 1 (S407). If it is 1 or more, complete the loop based on the calculation progress rate. On the other hand, if it is less than 1, add it to the calculation progress rate i (S408). After the addition process is completed, return to the process of calculating the current relative angles θ bm_i 、θ am_i 、θ bk_i of each joint (S402). If the calculation progress rate i becomes 1 (if the operation reaches the end), it is regarded as the calculation is completed, and the accumulated volume of excavation is set as the volume of soil relative to the given orbit (the return value of F in Equation 4).

[0092] Figure 6 is the flowchart of the replanning necessity determination unit 207 of this embodiment.

[0093] The replanning necessity determination of the replanning necessity determination unit 207 is based on the change of the progress rate t output by the progress management unit 208 with respect to time. Specifically, it is determined whether the progress rate t is in the same value state above the specified time t sat or more. If the progress rate t is in the same value state above the specified time t sat or more, it is determined that replanning is required (S502), otherwise, it is determined that replanning is not required (S503). The progress rate t being in the same value state above the specified time t sat or more means that in the excavation operation (during the operation of the work device), the actuators (boom cylinder 5, arm cylinder 6, bucket cylinder 7) that move the bucket 10 are in a stopped state.

[0094] Figure 7 is the flowchart of the progress management unit 208 of this embodiment.

[0095] First, derive the target relative angles θ now of the boom 8, arm 9, and bucket 10 as the target from the current trajectory plan and the current progress rate t bm_tar 、θ am_tar 、θ bk_tar output by the trajectory selection unit 205. Determine whether this target relative angle is the same as the current relative angles θ bm_now 、θ am_now 、θ bk_nowWhether the differences are all the preset value θ bm_min , θ am_min , θ bk_min Below (i.e., whether the following formulas 6 to 8 are all satisfied) (S601). When the difference between the target relative angle and the current relative angles θ bm_now , θ am_now , θ bk_now of the boom 8, the arm 9, and the bucket 10 are all the preset value θ bm_min , θ am_min , θ bk_min In the following case (i.e., when all of the following formulas 6 to 8 are satisfied), proceed to S602. In S602, determine whether the progress rate is 1 or more. When the progress rate is 1 or more, fix the progress rate at 1 (S603). On the other hand, when the progress rate is less than 1, add the progress rate (S604) and return to the initial state. The number added in S604 is set corresponding to the scale of the progress rate of the current trajectory plan.

[0096]

Mathematical formula 4

[0097] |θ bm_tar - θ bm_now | < θ bm_min Formula 6

[0098] |θ am_tar - θ am_now | < θ am_min Formula 7

[0099] |θ bk_ter - θ bk_now | < θ bk_min Formula 8

[0100] It should be noted that in the above formulas 6 to 8, the preset value θ bm_min , θ am_min , θ bk_min is used to determine whether to add to the progress (S601). However, if the relative angle is uniquely determined, it is also possible to indirectly specify the relative angle without directly specifying it. Specifically, it is the absolute angle of the tip position of the teeth and the bucket 10, the absolute angle of the bucket pin position (the pin connecting the arm 9 and the bucket 10) and the bucket 10, the absolute angle of each joint angle, etc.

[0101] <Effect specific to the method>

[0102] According to the first embodiment, in a work machine that pre-plans and performs an automatic excavation operation according to the plan, it is possible to re-plan the excavation trajectory and continuously execute the excavation operation even when the excavation becomes difficult.

[0103] [Embodiment 2]

[0104] <Configuration of Controller 20>

[0105] Figure 8 This is a system diagram of the control system installed in the controller 20 of the second embodiment. On the basis of the configuration of the first embodiment, the second embodiment is provided with a deepest distance calculation unit 701 in the excavation trajectory planning unit 200 of the controller 20.

[0106] Based on the replanning necessity determination output from the replanning necessity determination unit 207, the terrain shape output from the terrain shape calculation unit 203, the relative angle output from the angle detection device 21, and the geometry of the bucket 10 output from the working device geometry storage unit 206, the deepest distance calculation unit 701 calculates the deepest distance, which is the maximum distance from the ground surface (the surface of the excavation object) to any point on the bucket 10 at the time point when the replanning necessity determination unit 207 determines that replanning is necessary, and outputs it to the replanning unit 204.

[0107] <Operation of Controller 20>

[0108] Figure 9 This is a flowchart of the deepest distance calculation unit 701 of this embodiment.

[0109] First, the replanning necessity determination unit 207 determines whether it has changed from a state where replanning is not required to a state where replanning is required (S801). If it is in a state of changing from not required to required in S801, based on the bucket geometry and Equation 5, the coordinates of any point (point Q) on the bucket 10 are calculated, and the distance Lp (the deepest distance) between the point P that is the farthest from the ground surface of the terrain shape and the ground surface of the terrain shape is calculated (S802). In other words, the distance Lp, which is the maximum distance from the ground surface (the surface of the excavation object) to any point on the bucket 10 at the time point when the replanning necessity determination unit 207 determines that replanning is necessary, is calculated as the deepest distance. For example, Figure 10 shows the relationship between the tip of any point (point Q) on the bucket 10 and the deepest distance Lp.

[0110] The replanning unit 204 replans the excavation trajectory (trajectory planning (re)) of the bucket 10 based on the deepest distance Lp output from the deepest distance calculation unit 701 so as not to dig deeper than the deepest distance Lp from the terrain shape (in other words, to make the distance from the ground surface (the surface of the excavation object) to any point on the bucket 10 less than or equal to the deepest distance Lp).

[0111] The replanning method only needs to be able to consider the above-mentioned constraint conditions of the deepest distance. For example, it can also be Equation 9 obtained by adding a function to the deepest distance to the evaluation value J in Equation 4.

[0112]

Mathematical formula 5

[0113]

[0114] G: Function for calculating the deepest distance at any point on the bucket (equivalent to S802)

[0115] ω: Any weight

[0116] <Effect specific to the method>

[0117] According to the second embodiment, since the excavation trajectory is replanned in such a way as to avoid digging deeper than the depth that requires re - planning judgment, the possibility of becoming a state that requires replanning again is reduced, and the excavation operation can be smoothly continued.

[0118] [Embodiment 3]

[0119] In the first embodiment, due to the performance of the controller 20 and the computational load of replanning, replanning takes time. Therefore, even if it is determined that replanning is required based on the replanning necessity judgment, the vehicle body has to be stopped before the completion of the replanning operation. Embodiment 3 is a solution to this problem.

[0120] <Configuration of the controller 20>

[0121] Figure 11 is the system diagram of the control system incorporated in the controller 20 of the third embodiment. Based on the configuration of the first embodiment, the third embodiment further includes a replanning time recording unit 901 in the excavation trajectory planning unit 200 of the controller 20. In addition, it includes a replanning necessity judgment unit 902 that replaces the replanning necessity judgment unit 207 and a replanning unit 903 that replaces the replanning unit 204.

[0122] The replanning time recording unit 901 records (stores) the time of the computational replanning (the replanning operation time t cal ). The replanning necessity judgment unit 902 that replaces the replanning necessity judgment unit 207 makes a replanning necessity judgment based on the replanning operation time t cal output by the replanning time recording unit 901 and outputs a calculation start trigger. In addition, the replanning unit 903 that replaces the replanning unit 204 does not use the replanning necessity judgment of the replanning unit 204, but replans the excavation trajectory (trajectory planning (re - )) of the bucket 10 based on the calculation start trigger output by the replanning necessity judgment unit 902.

[0123] It should be noted that in the replanning time recording unit 901, the replanning operation time t cal is determined in advance, but it can also calculate the system load, communication load, etc. and set it to be variable.

[0124] <Operation of the controller 20>

[0125] Figure 12 This is a flowchart of the re-planning necessity determination unit 902 of this embodiment.

[0126] First, corresponding to the re-planning operation time t cal To change the specified time t that needs to be re-planned sat2 (S1001).

[0127] Reschedule operation time t cal and the specified time t sat2 It suffices to satisfy the relationship of the following formula 10, and can be determined according to the following formula 11, for example.

[0128]

Mathematical formula 6

[0129]

[0130] t sat2 =t sat -t cat Formula 11

[0131] t sat : An arbitrary value determined by the replan necessity determination unit 207

[0132] Next, determine whether the progress rate t has passed the specified time t sat2 If the progress rate t is less than the specified time t in S1002 sat2 , it is determined that the re-planning state is not required (S1006). On the other hand, if the progress rate t is the specified time t in S1002 sat2 If the calculation start trigger is set to start (S1003), the progress rate t is set to start at the specified time t sat2 The above-mentioned equivalent state means that the actuators (boom cylinder 5, arm cylinder 6, bucket cylinder 7) that move bucket 10 are stopped during the excavation operation (operation of the working device). The replanning unit 903 starts replanning the excavation trajectory of bucket 10 (trajectory plan (re-plan)) in response to the calculation start trigger.

[0133] After the processing of S1003, it is determined whether the re-planning calculation time t has passed. cal (S1004) In S1004, it is determined that the re-planning calculation time t has not passed. cal In the case of , it is determined whether the progress rate t has been changed (S1007). In the case of determining in S1007 that the progress rate t has been changed, that is, in the re-planned operation (from the determination that re-planning is required to the re-planning operation time tcal ) When the progress rate t has changed, it is determined that replanning is not required, and the calculation start trigger is set to off to interrupt the replanning (S1007 - S1008). On the other hand, when it is determined in S1004 that the replanning operation time t cal has passed, it is determined that replanning is required (S1005). When it is determined that replanning is required, the excavation trajectory replanned by the trajectory selection unit 205 in the replanning unit 903 (trajectory plan (re - plan)) is selected as the new trajectory plan.

[0134] <Specific effects of the method>

[0135] According to the third embodiment, by performing a replanning necessity determination prediction corresponding to the replanning operation time t of the replanning unit 903 by the replanning necessity determination unit 902, it is possible to reduce the stoppage of the work device caused by the replanning operation during the replanning of the excavation trajectory. cal

[0136] [Embodiment 4]

[0137] <Configuration of the controller 20>

[0138] Figure 13 is a system diagram of the control system incorporated in the controller 20 of the fourth embodiment. The fourth embodiment is based on the configuration of the first embodiment, and for example, a display device (re - planning display unit) 25 is provided on the upper revolving body 1B. It should be noted that the display device 25 can also be placed outside the excavator 1 via wireless means or the like.

[0139] <Operation>

[0140] Figure 14 is a display example shown on the display device 25 of the fourth embodiment.

[0141] On the display device 25, at least the display capable of grasping the geometric relationship of the front device 1A, the display indicating the trajectory of the trajectory plan (re - plan) replanned by the replanning unit 204, the display indicating the trajectory of the current trajectory plan selected by the trajectory selection unit 205, and the terrain shape calculated by the terrain shape calculation unit 203 are displayed (output). In addition, the replanning necessity determination of the replanning necessity determination unit 207 can also be displayed (output) on the display device 25.

[0142] It should be noted that for the display indicating the trajectory, it is only necessary to confirm the relative angle. For example, it is the absolute angle between the tip position of the teeth and the bucket, the absolute angle between the bucket pin position and the bucket, etc.

[0143] <Specific effects of the method>

[0144] ​According to the fourth embodiment, since the status before and after the excavation trajectory is changed (before and after re-planning) is clearly displayed, the operator can confirm the automatic excavation operation.

[0145] [Summarize]

[0146] As described above, in the control system of the working device (excavator 1) of the present embodiment, the excavation action of the working device is controlled in the (automatic) excavation operation of the working machine equipped with the working device (front device 1A), and the control system of the working machine is equipped with a controller 20, which has: an excavation trajectory planning unit 200, which plans the excavation trajectory of the working device based on a predetermined volume of an excavation object (sand and soil) to be excavated (in a manner such that the working device excavates an excavation object (sand and soil) of a predetermined volume); and a planning execution unit 201, which controls the action of the working device (an execution mechanism that causes the working device to act) to realize the excavation trajectory planned by the excavation trajectory planning unit 200, and the excavation trajectory planning unit 200 includes: an initial planning unit 202, which is used in the working device to plan the excavation trajectory of the working device. before the working device performs an action (before starting the excavation action); a re-planning necessity judgment unit 207, which judges whether it is necessary to re-plan the excavation trajectory according to the change in the progress rate of the working device performing the action based on the excavation trajectory planned by the initial planning unit 202 relative to time, in order to enable the working device to continue the excavation action while the working device is performing the action based on the excavation trajectory planned by the initial planning unit 202 (during the excavation action); and a re-planning unit 204, which re-plans the excavation trajectory for enabling the working device to continue the excavation action while the working device is performing the action based on the excavation trajectory planned by the initial planning unit 202 (during the excavation action) when the re-planning necessity judgment unit 207 determines that re-planning is necessary.

[0147] According to this embodiment, even if the excavation operation cannot be continued due to unexpected factors during the excavation operation, the excavation trajectory can be replanned and the excavation operation can be continued without incomplete excavation or interruption of work.

[0148] In addition, in the control system of the working device (excavator 1) according to the present embodiment, the controller 20 includes a surrounding shape calculation unit (terrain shape calculation unit 203) that acquires the surrounding shape (terrain shape) of the excavation object around the excavation trajectory of the working device, and a working device geometry storage unit 206 that stores the geometry of the working device. The replanning unit 204 replans the excavation trajectory to excavate the same volume as the volume of the excavation object (sand) expected to be excavated by the excavation trajectory planned by the initial planning unit 202, based on the surrounding shape (terrain shape) of the excavation object acquired by the surrounding shape calculation unit (terrain shape calculation unit 203) and the geometry of the working device stored in the working device geometry storage unit 206.

[0149] According to the present embodiment, based on the above effects, since the excavation trajectory is replanned in such a way that the volume of the excavation trajectory before replanning and the subsequent excavation trajectory is the same, even if the excavation trajectory is replanned, the same amount of excavation object (sand) can be ensured within the working device.

[0150] In addition, in the control system of the working device (excavator 1) according to the present embodiment, the replanning necessity determination unit 207 determines whether to replan the excavation trajectory at least based on the stop state of the actuator that actuates the working device during the operation of the working device (during the excavation operation) of the work machine (determining whether excavation can continue; determining the stop of the excavation operation).

[0151] According to the present embodiment, it is possible to more accurately determine the need to replan the excavation trajectory.

[0152] In addition, in the control system of the working device (excavator 1) according to the present embodiment, the controller 20 includes: a surrounding shape calculation unit (terrain shape calculation unit 203) that acquires the surrounding shape (terrain shape) of the excavation object around the excavation trajectory of the working device; and a deepest distance calculation unit 701 that calculates the deepest distance, which is the maximum distance from the surface of the excavation object (ground surface) to any point on the working device, based on the surrounding shape (terrain shape) of the excavation object acquired by the surrounding shape calculation unit (terrain shape calculation unit 203) at the time when the replanning necessity determination unit 207 determines that replanning is necessary and the geometric information of the working device. The replanning unit 204 replans the excavation trajectory so that the distance from the surface of the excavation object (ground surface) to any point on the working device is equal to or less than the deepest distance calculated by the deepest distance calculation unit 701.

[0153] According to this embodiment, since the excavation trajectory is re-planned to be below the depth from the surface (ground surface) of the excavation object at the moment when the excavation trajectory needs to be re-planned, the possibility that the re-planned excavation trajectory needs to be re-planned again can be reduced.

[0154] In addition, in the control system of the working device (excavator 1) of this embodiment, the re-planning necessity determination unit 207 performs a re-planning necessity determination prediction corresponding to the re-planning operation time of the re-planning unit 204.

[0155] According to this embodiment, since the excavation trajectory can be re-planned before the re-planning of the excavation trajectory is required instead of after the re-planning of the excavation trajectory is required, the amount of operation time for the re-planning of the excavation trajectory is not required, and the excavation trajectory can be re-planned by stopping the vehicle body in the state where re-planning is required.

[0156] In addition, in the control system of the working device (excavator 1) of this embodiment, the controller 20 includes a re-planning display unit (display device 25), and the re-planning display unit (display device 25) outputs (displays) the re-planned excavation trajectory of the re-planning unit 204 and the necessity of re-planning the excavation trajectory determined by the re-planning necessity determination unit 207.

[0157] According to this embodiment, since the re-planned plan and the presence or absence of re-planning are output, it is easy to confirm the presence or absence of re-planning and the changed plan from the outside.

[0158] It should be noted that the present invention is not limited to the above-described embodiments and includes various modification modes. For example, the above-described embodiments are the contents described in detail for clearly and understandably explaining the present invention, and are not necessarily limited to having all the configurations described. In addition, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and in addition, the configuration of another embodiment can be added to the configuration of a certain embodiment. In addition, addition, deletion, and replacement of other configurations can be performed on a part of the configuration of each embodiment.

[0159] In addition, some or all of the functions of the controller in the above-described embodiments can also be implemented in hardware by, for example, an integrated circuit design. In addition, it can also be implemented by software by interpreting and executing a program for implementing each function by a processor. Information such as programs, tables, and files for implementing each function can be stored not only in the storage device in the controller but also in a recording device such as a hard disk, an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.

[0160] Description of reference numerals

[0161] 1 Hydraulic Excavator

[0162] 1A Front Unit

[0163] 1B Upper Swing Structure

[0164] 1C Lower Traveling Structure

[0165] 3 Traveling Motor

[0166] 4 Swing Device

[0167] 5 Boom Hydraulic Cylinder

[0168] 6 Arm Hydraulic Cylinder

[0169] 7 Bucket Hydraulic Cylinder

[0170] 8 Boom

[0171] 9 Arm

[0172] 10 Bucket

[0173] 11 Swing Motor

[0174] 13 Bucket Linkage

[0175] 20 Controller

[0176] 21 Angle Detection Device

[0177] 22 Terrain Measurement Device

[0178] 25 Display Device (Redesign Display Section) (Example 4)

[0179] 200 Excavation Trajectory Planning Section

[0180] 201 Planning Execution Section

[0181] 202 Initial Planning Section

[0182] 203 Terrain Shape Calculation Section (Peripheral Shape Calculation Section)

[0183] 204 Redesign Planning Section

[0184] 205 Trajectory Selection Section

[0185] 206 Working Device Geometry Storage Section

[0186] 207 Redesign Necessity Judgment Section

[0187] 208 Progress Management Section

[0188] 209 Target Value Output Section

[0189] 210 Actuator Control System

[0190] 701 Deepest Distance Calculation Unit (Example 2)

[0191] 901 Reprogramming Time Recording Unit (Example 3)

[0192] 902 Reprogramming Necessity Judgment Unit (Example 3)

[0193] 903 Reprogramming Unit (Example 3).

Claims

1. A control system for a work machine that controls the excavation operation of the work machine equipped with a work device during the excavation operation. The control system of the work machine is characterized by comprising a controller. The controller has: The excavation trajectory planning unit plans the excavation trajectory of the work device based on the volume of the excavation object to be excavated as preset in advance; And A plan execution unit that controls the operation of the work device to achieve the excavation trajectory planned by the excavation trajectory planning unit. The excavation trajectory planning unit includes: An initial planning unit that plans the excavation trajectory before the work device operates. A replanning necessity determination unit that determines whether replanning of the excavation trajectory is necessary based on the change over time of the progress rate of the operation of the work device along the excavation trajectory planned by the initial planning unit in order to keep the work device continuously performing the excavation operation during the operation of the work device along the excavation trajectory planned by the initial planning unit. A replanning unit that, when it is determined by the replanning necessity determination unit that replanning is necessary, replans the excavation trajectory for keeping the work device continuously performing the excavation operation during the operation of the work device along the excavation trajectory planned by the initial planning unit.

2. The control system of the work machine according to claim 1, characterized in that The controller includes: A peripheral shape calculation unit that acquires the peripheral shape of the excavation object around the excavation trajectory of the work device; and A work device geometry storage unit that stores the geometry of the work device. The replanning unit replans the excavation trajectory for excavating a volume equal to the volume of the excavation object expected to be excavated along the excavation trajectory planned by the initial planning unit based on the peripheral shape of the excavation object acquired by the peripheral shape calculation unit and the geometry of the work device stored in the work device geometry storage unit.

3. The control system of the work machine according to claim 1, characterized in that The replanning necessity determination unit determines whether replanning of the excavation trajectory is necessary based at least on the stop state of the actuator that operates the work device during the operation of the work device of the work machine.

4. The control system of the work machine according to claim 1, characterized in that The controller includes: A peripheral shape calculation unit that acquires the peripheral shape of the excavation object around the excavation trajectory of the work device; and A deepest distance calculation unit that calculates the deepest distance, which is the maximum distance from the surface of the excavation object to an arbitrary point on the work device, based on the peripheral shape of the excavation object acquired by the peripheral shape calculation unit and the geometric information of the work device at the time when it is determined by the replanning necessity determination unit that replanning is necessary. The replanning unit replans the excavation trajectory so that the distance from the surface of the excavation object to an arbitrary point on the work device is equal to or less than the deepest distance calculated by the deepest distance calculation unit.

5. The control system of the construction machine according to claim 1, wherein the replanning necessity determination unit performs a replanning necessity determination prediction corresponding to the replanning operation time of the replanning unit.

6. The control system of the construction machine according to claim 1, wherein the controller includes a replanning display unit that outputs the excavating trajectory after replanning by the replanning unit and the necessity of replanning the excavating trajectory determined by the replanning necessity determination unit.

7. The control system of the construction machine according to claim 1, wherein when the replanning unit replans the excavating trajectory, an error signal is issued if the replanning is not completed within a preset time.

8. The control system of the construction machine according to claim 1, wherein when the replanning unit replans the excavating trajectory, the operation of the construction machine is stopped if the replanning is not completed within a preset time.

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