Work machine

Abstract

Provided is a work machine capable of satisfactorily controlling an attachment in response to a change in the operation of the attachment. The work machine comprises an attachment and a control unit that controls the operation of the attachment so that the attachment moves along a target operation trajectory. The operation of the attachment includes a plurality of operation phases (PH1 to PH4), each of which includes at least one of an accelerating operation, a constant-speed operation, and a decelerating operation. In an object operation phase selected from among the plurality of operation phases, the control unit controls the operation speed of the attachment on the basis of a time integral value of the operation speed.

Description

Work machine

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

[0002] Patent Document 1 discloses a work machine, which includes a lower traveling body, an upper revolving body, an attachment, control means, determination means, and classification means. The upper revolving body is rotatably attached to the upper part of the lower traveling body. The attachment is rotatably attached to the upper revolving body. A series of operations performed by the upper revolving body and the attachment are taught to the control means, and the series of operations includes a plurality of phases. The determination means determines the current operation phase based on at least one of the position of the attachment, the operations of the upper revolving body and the attachment, and the posture of the attachment. The classification means classifies the series of operations into the plurality of operation phases based on the determination result of the determination means.

[0003] After learning the series of operations by the teaching or the like, for example, when it is desired to adjust the operation speed or the like related to the movement of the attachment according to the situation at the work site.

[0004] Japanese Patent Application Laid-Open No. 2023-74041

[0005] An object of the present invention is to provide a work machine capable of controlling an attachment in response to changes in operation speed or the like.

[0006] Provided is a work machine, which includes an attachment capable of performing an operation for work, and a control unit that controls the movement of the attachment so that the attachment moves along a target operation trajectory. The operation of the attachment along the target operation trajectory includes a plurality of operation phases that are continuous with each other. The plurality of operation phases includes at least one of an acceleration operation, a constant-speed operation, and a deceleration operation. The control unit is configured to control the operation of the attachment in the target operation phase selected from the plurality of operation phases based on a time integration value that is a value obtained by integrating the operation speed, which is the speed of the operation of the attachment, over an elapsed time.

[0007] This is a side view of a work machine according to the first embodiment of the present invention. This is a block diagram showing a control unit and its input / output included in the work machine. This is a plan view showing the movement of an attachment during excavation work by the work machine. This is a side view showing the first operation phase according to the first embodiment. This is an operation speed graph according to the first embodiment. This is an operation speed graph after the operation time of the second operation phase has been updated in the first embodiment. This is an operation speed graph according to the second embodiment of the present invention. This is an operation speed graph according to the first modification of the second embodiment. This is an operation speed graph according to the second modification of the second embodiment. This is a diagram showing the correction of the target operation trajectory according to the third embodiment of the present invention.

[0008] Embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0009] A first embodiment of the present invention will be described with reference to Figures 1 to 6.

[0010] Figure 1 shows a work machine 1 according to the first embodiment. The work machine 1 is a shovel. The work machine 1 comprises a lower traveling body 10, an upper rotating body 20 attached to the lower traveling body 10 so as to be able to rotate relative to the lower traveling body 10, and a work device 30 attached to the upper rotating body 20 so as to be able to raise and lower. The work machine according to the present invention may be a work machine other than a shovel.

[0011] The lower traveling body 10 illustrated in Figure 1 is a crawler-type traveling body including a pair of crawlers. However, the work machine according to the present invention is not limited to one that includes a crawler-type traveling body.

[0012] The upper slewing body 20 includes a driver's cab 21 and a machine room 22. The driver's cab 21 allows an operator to board it for operation. The machine room 22 is located behind the driver's cab 21. An operating unit (not shown) is provided in the driver's cab 21, which provides controls for, for example, moving the lower traveling body 10, the upper slewing body 20, and the work device 30 and other elements. The upper slewing body 20 further includes a slewing device 24 shown in Figure 2, which includes, for example, a slewing motor to slewing the upper slewing body 20 relative to the lower traveling body 10.

[0013] As shown in Figure 1, the work device 30 includes a boom 31, an arm 32, a tip attachment 33, a boom cylinder 34, an arm cylinder 35, and an attachment cylinder 36.

[0014] The boom 31 has a boom base end and a boom tip on the opposite side, and the boom base end is rotatably connected to the upper slewing body 20 so that the boom 31 can perform luffing movements relative to the upper slewing body 20. The arm 32 has an arm base end and an arm tip on the opposite side, and the arm base end is rotatably connected to the boom tip. The attachment 33 is rotatably connected to the arm tip and performs operations for work. In the work machine 1 illustrated in Figure 1, the attachment 33 is a bucket.

[0015] Each of the cylinders 34, 35, and 36 is a hydraulic cylinder capable of extending and retracting. The boom cylinder 34 extends and retracts to cause the boom 31 to perform luffing and raising movements relative to the upper slewing body 20. The arm cylinder 35 extends and retracts to cause the arm 32 to rotate relative to the boom 31. The attachment cylinder 36 extends and retracts to cause the attachment 33 to rotate relative to the arm 32.

[0016] The aforementioned work machine 1 further comprises the control system shown in Figure 2. The control system includes a control unit 40, a storage unit 42, a detection unit 44, a plurality of angle sensors, a GNSS 48, a compass 50, a video camera 52, and an input / output device 54.

[0017] The control unit 40 is located in the driver's cab 21 and controls the operation of the work machine 1 during automatic operation. For example, the control unit 40 controls the operation of the attachment 33 and the movement of the work machine 1. Specifically, as shown in Figure 2, the control unit 40 controls the rotational movement of the upper rotating body 20, the travel movement of the lower traveling body 10, and the operation of the work device 30, respectively.

[0018] The control unit 40 includes a computer. The control unit 40 may be composed of a device such as a tablet or a notebook PC. The control unit 40 may be configured to control the operation of the work machine 1 by transmitting control commands to the work machine 1 via wired communication or wireless communication.

[0019] The detection unit 44 detects the state of the front of the work machine 1. The detection unit 44 is positioned, for example, on the outer surface of the top wall of the operator's cab 21. In this embodiment, the detection unit 44 is composed of a 3D-LiDAR that acquires three-dimensional point cloud data. The detection unit 44 may also include a stereo camera.

[0020] The plurality of angle sensors include a boom angle sensor 37, an arm angle sensor 38, and an attachment angle sensor 39. The boom angle sensor 37 acquires the tilt angle of the boom 31 relative to the upper slewing body 20. The arm angle sensor 38 acquires the tilt angle of the arm 32 relative to the boom 31. The attachment angle sensor 39 acquires the tilt angle of the attachment 33 relative to the arm 32.

[0021] The control unit 40 controls the drive of the work device 30 based on information input from the multiple angle sensors, including the boom angle sensor 37, the arm angle sensor 38, and the attachment angle sensor 39, i.e., angle information.

[0022] The GNSS 48 and the compass 50 constitute a position information acquisition unit and acquire position information such as the latitude, longitude, altitude of the reference position of the upper rotating body 20, and the bearing of the upper rotating body 20. The GNSS 48 can be replaced with GPS. The bearing of the upper rotating body 20 is also the bearing of the work device 30 attached to the upper rotating body 20.

[0023] The information acquired by the position information acquisition unit is input to the control unit 40. Based on the preset target route and the position information acquired by the position information acquisition unit, the control unit 40 controls the drive of the lower traveling body 10 so that the work machine 1 moves along the target operating trajectory.

[0024] Furthermore, the control unit 40 also controls the rotational movement of the upper rotating body 20 during excavation work, etc., based on information input from a plurality of sensors provided on the upper rotating body 20.

[0025] The position at which the boom 31 is connected to the upper slewing body 20 is constant on the upper slewing body 20. Therefore, the control unit 40 can determine the position of the boom 31 with respect to the reference position of the upper slewing body 20.

[0026] The storage unit 42 stores necessary information, including the lengths of the boom 31, the arm 32, and the attachment 33. This information, along with the position of the boom 31 relative to the upper slewing body 20, the orientation of the upper slewing body 20, and the angle information obtained by the control unit 40, enables the control unit 40 to control the drive of the work device 30.

[0027] The video camera 52 captures images for monitoring the area in front of the work machine 1 and inputs them to the control unit 40. The video camera 52 is positioned, for example, on the outer surface of the ceiling wall of the operator's cab 21.

[0028] The work machine 1 further comprises a plurality of control valves for controlling the drive of the work device 30 by the control unit 40. The plurality of control valves include a boom control valve, an arm control valve, an attachment control valve, a boom pilot pressure operating valve, an arm pilot pressure operating valve, and an attachment pilot pressure operating valve. The boom control valve is configured as a pilot-operated hydraulic switching valve and changes the pressure of the hydraulic fluid supplied to the boom cylinder 34 in accordance with the boom pilot pressure input to the boom control valve. The arm control valve is configured as a pilot-operated hydraulic switching valve and changes the pressure of the hydraulic fluid supplied to the arm cylinder 35 in accordance with the arm pilot pressure input to the arm control valve. The attachment control valve is configured as a pilot-operated hydraulic switching valve and changes the pressure of the hydraulic fluid supplied to the attachment cylinder 36 in accordance with the attachment pilot pressure input to the attachment control valve. The boom pilot pressure operating valve changes the boom pilot pressure input to the boom control valve in accordance with an electrical signal input from the control unit 40. The arm pilot pressure operating valve changes the arm pilot pressure input to the arm control valve in response to an electrical signal input from the control unit 40. The attachment pilot pressure operating valve changes the attachment pilot pressure input to the attachment control valve in response to an electrical signal input from the control unit 40.

[0029] The input / output device 54 allows an operator to operate the input / output device 54 and generates an instruction signal corresponding to the operation and inputs it to the control unit 40. The input / output device 54 is composed of, for example, a portable terminal such as a tablet. The input / output device 54 includes a touch panel screen, and settings related to the attachment operating speed are made by touch operations or other operations made on the screen by the operator.

[0030] The screen may display images captured by the video camera 52 as needed.

[0031] The input / output device 54 may also be an input device fixed inside the driver's cab 21.

[0032] Figure 3 shows a series of operations of the attachment 33 during excavation work performed by the work machine 1. The series of operations is a so-called loop operation that includes the operation of scooping up the work object 60, such as soil, at the location where the work object 60 is located (in the example shown in Figure 3, the excavation site), the operation of discharging the scooped work object 60 onto the bed of the dump truck 2, i.e., soil removal, and the operation of returning to the collection location.

[0033] The memory unit 42 stores information regarding the target operating trajectory. The target operating trajectory is the trajectory along which the attachment tip 33F, which is the tip of the attachment 33 shown in Figure 1, is targeted to move during the loop operation.

[0034] The target operating trajectory stored in the memory unit 42 is preferably set in advance based on excavation work performed by a skilled operator. The memory unit 42 stores, as information relating to the target operating trajectory, for example, a plurality of coordinates that the attachment tip 33F should pass through, based on the reference position of the upper rotating body 20 described above.

[0035] The control unit 40 obtains information such as the depth of the excavation site from the three-dimensional point cloud data acquired by the detection unit 44 (3D-LiDAR), selects an operating trajectory corresponding to the depth as the target operating trajectory, and controls the attachment tip 33F to move along the target operating trajectory. In other words, the control unit 40 moves the attachment tip 33F along the target operating trajectory.

[0036] In this first embodiment, in order to perform speed control and the like, the loop motion for the excavation work, that is, the movement of the attachment tip 33F along the target motion trajectory, is defined by a plurality of motion phases, namely a first motion phase PH1, a second motion phase PH2, a third motion phase PH3, and a fourth motion phase PH4. In other words, the operation of the attachment 33 includes the plurality of motion phases, which are the first to fourth motion phases PH1 to PH4.

[0037] The target operating trajectories corresponding to the first operating phase PH1, the second operating phase PH2, the third operating phase PH3, and the fourth operating phase PH4 are indicated by arrows A1, A2, A3, and A4 in Figure 3, respectively, and each of the first to fourth operating phases PH1 to PH4 includes at least one operation from among acceleration, constant velocity, and deceleration. Specifically, in the first embodiment, each of the first to fourth operating phases PH1 to PH4 includes the acceleration, constant velocity, and deceleration operations.

[0038] The acceleration operation, constant velocity operation, and deceleration operation included in the first operation phase PH1 will be described below, using the first operation phase PH1 as an example.

[0039] As indicated by arrow A1 in Figures 3 and 4, the first operation phase PH1 is the operation of scooping up the work object 60, such as soil, with the attachment 33 (bucket). Specifically, in the first operation phase PH1, control is performed to rotate the attachment 33 so that it moves along the target operation trajectory indicated by arrow A1 from a state in which the tip of the attachment 33F is in contact with the work object 60 such as soil, thereby causing the attachment 33 to scoop up the work object 60. The first operation phase PH1, in which the tip of the attachment 33F scoops up the work object 60, includes an acceleration operation to bite the tip of the attachment 33F into the work object 60, a constant velocity operation which is the rotation of the attachment 33 in the cloud direction after the acceleration operation is completed, and a deceleration operation from when it approaches the scooping completion position until it stops at the scooping completion position.

[0040] Figure 5 shows an operating speed graph, which shows the change in operating speed over time in each of the first operating phases PH1, PH2, PH3, and PH4. Specifically, the vertical axis of the operating speed graph represents the operating speed (mm / sec), which is the speed of movement of the attachment tip 33F, and the horizontal axis represents the elapsed time (sec), which is the time elapsed since the start of movement of the attachment tip 33F. The operating speed graph is stored in the storage unit 42 in association with the target operating trajectory related to the loop operation.

[0041] In the operating speed graph shown in Figure 5, the first operating phase PH1, the second operating phase PH2, the third operating phase PH3, and the fourth operating phase PH4 are arranged in succession from left to right, that is, from the start of operation.

[0042] FIG. 5 shows a first speed area S1, a second speed area S2, a third speed area S3, and a fourth speed area S4, which correspond to the time integral values of the operating speeds in the first operation phase PH1, the second operation phase PH2, the third operation phase PH3, and the fourth operation phase PH4, respectively. That is, the time integral value of the operating speed corresponds to the area vertically sandwiched between the operation speed graph, which is a line showing the relationship between the elapsed time and the operating speed, and the elapsed time axis, which is the horizontal axis in FIG. 5. For example, the first speed area S1 shown in FIG. 1 is the area vertically sandwiched between the line 61 showing the operating speed in the first operation phase PH1 and the horizontal axis. Similarly, the second speed area S2, the third speed area S3, and the fourth speed area S4 are the areas vertically sandwiched between the lines 62, 63, and 64 showing the operating speeds in the second operation phase PH2, the third operation phase PH3, and the fourth operation phase PH4, respectively, and the horizontal axis.

[0043] As shown by an arrow A2 in FIG. 3, the second operation phase PH2 is an operation in which the upper swing body 20 swings with the work object 60 lifted up and moves the attachment 33 to a dumping position above the loading platform of the dump truck 2. Similar to the first operation phase PH1, the second operation phase PH2 involving the swing of the upper swing body 20 includes an acceleration operation at the start of the swing of the upper swing body 20, a constant speed operation, which is a swing operation after the acceleration operation ends, and a deceleration operation from when the attachment 33 approaches the dumping position until it stops at the dumping position. The line 62 shown in FIG. 5 shows the time change of the operating speed in the second operation phase PH2, that is, the relationship between the elapsed time and the operating speed, and the second speed area S2, which is the area between the line 62 and the horizontal axis, corresponds to the time integral value of the operating speed in the second operation phase PH2.

[0044] The third operation phase PH3 is the operation of discharging the work object 60 from the attachment 33 at the soil discharge position above the bed of the dump truck 2, as indicated by arrow A3 in Figure 3. The third operation phase PH3, like the first operation phase PH1, includes an acceleration operation when the rotation of the attachment 33 for soil discharge begins, a constant velocity operation which is the rotation after the acceleration operation is completed, and a deceleration operation from when the attachment 33 approaches the rotation end position until it stops at the rotation end position. The line 63 shown in Figure 5 shows the time change of the operation speed (speed of the third operation) in the third operation phase PH3, that is, the relationship between elapsed time and the operation speed, and the third velocity area S3, which is the area of ​​the region between the line 63 and the horizontal axis, corresponds to the time integral value of the operation speed in the third operation phase PH3.

[0045] The fourth operation phase PH4 is an operation in which the upper rotating body 20 rotates back to return the attachment 33 to the excavation position in order to resume excavation, as indicated by arrow A4 in Figure 3. Thus, the fourth operation phase PH4, which includes the return rotation operation of the upper rotating body 20, includes an acceleration operation at the start of rotation of the upper rotating body 20, a constant velocity operation which is the rotation operation after the acceleration operation is completed, and a deceleration operation from when the attachment 33 approaches the excavation position until it stops at the excavation position, similar to the first operation phase PH1. The line 64 shown in Figure 5 shows the time change of the operation speed (speed of the fourth operation) in the fourth operation phase PH4, that is, the relationship between elapsed time and the operation speed, and the fourth velocity area S4, which is the area of ​​the region between the line 64 and the horizontal axis, corresponds to the time integral value of the operation speed in the fourth operation phase PH4.

[0046] The use of the aforementioned operating speed graph, particularly the use of the time integral value of the operating speed, enables the control of the work machine 1 in response to changes in the operating speed, etc. The control will be described in detail below.

[0047] When a change command is input from the input / output device 54 or an input unit substituting therefor for at least one target operation phase selected from the first to fourth operation phases PH1 to PH4, the control unit 40 makes a change corresponding to the change command and controls the operation of the attachment 33 (the attachment tip 33F in the present embodiment) based on the speed area corresponding to the target operation phase among the first to fourth speed areas S1 to S4, that is, the time integral value of the operation speed.

[0048] When the command input to the control unit 40 includes a fixed command for fixing any one of the operation speeds or the time change rate (acceleration or deceleration) of the operation speed in the acceleration operation, constant speed operation, and deceleration operation included in the target operation phase (the second operation phase PH2 in the present embodiment), the speed of the operation not targeted by the fixed command (in this example, the constant speed operation speed which is the speed of the constant speed operation) is controlled based on the speed area (in this example, the second speed area S2, that is, the time integral value of the operation speed of the second operation) corresponding to the operation speed or the time change rate targeted by the fixed command. For example, when the acceleration and deceleration in the acceleration operation and the deceleration operation among the acceleration operation, the constant speed operation, and the deceleration operation are respectively targeted by the fixed command, the control unit 40 sets the constant speed operation speed corresponding to the acceleration and the deceleration fixed by the fixed command.

[0049] As such a case, in response to an operator giving an operation (for example, a touch operation) to the input / output device 54 in order to avoid sudden acceleration and deceleration of the attachment 33, the input / output device 54 prohibits changes in the acceleration and deceleration in the acceleration operation and the deceleration operation in the second operation phase PHⅡ, that is, fixes the acceleration and deceleration, and the operation speed is newly set so as to change the operation time of the second operation phase PH2, that is, the time required to perform the second operation related to the second operation phase PH2.

[0050] In this case, the control of the operating speed performed by the control unit 40 will be described below with reference to Figure 6. The contents of the following description can also be applied to other operating phases other than the second operating phase PH2, namely the first operating phase PH1, the third operating phase PH3, and the fourth operating phase PH4. Furthermore, the description can be applied not only to operating phases that include acceleration, constant speed, and deceleration, as in the second operating phase PH2 of this first embodiment, but also to operating phases that include either acceleration or deceleration and constant speed.

[0051] Figure 6 shows an example in which the operation time of the second operation phase PH2 is newly set to an operation time T2' (= T2 - ΔT) that is shorter by time ΔT than the previous operation time T2. The upper part of Figure 6 shows the old operation speed graph before the operation time was changed, i.e., the same operation speed graph as shown in Figure 5, and the lower part shows the operation speed graph with the new operation time set, i.e., the operation speed graph after the change. The setting of the new operation time T2', i.e., inputting a command to change the operation time to the control unit 40, can be done, for example, by an operator touching the input / output device 54 to specify the new operation time T2'.

[0052] In this way, while the operating time of the target operating phase selected from the plurality of operating phases (in this example, the second operating phase PH2) is newly set, if the acceleration and deceleration in the acceleration and deceleration operations are fixed as described above, the control unit 40 controls the speed of the constant-velocity operation that is not subject to the fixed command among the operations (second operations) in the operating phase targeted by the command (in this example, the second operating phase PH2), so as to keep the velocity area (in this example, the second velocity area S2) constant regardless of the change in operating time (in this example, the change from operating time T2 to operating time T2'). That is, regardless of the change in operating time, the control unit 40 controls the constant-velocity operation by increasing the constant-velocity operation speed in accordance with the shortening of the second operating phase PH2 without changing the acceleration of the acceleration operation and the deceleration of the deceleration operation, thereby keeping the second velocity area S2, which corresponds to the time integral value of the operating speed, constant, that is, controlling the second velocity area S2 after the change in operating time to match the second velocity area S2 before the change.

[0053] The control involves increasing the constant-velocity operation in accordance with the shortening of the operation time of the second operation phase PH2, but the acceleration of the acceleration operation and the deceleration of the deceleration operation are kept constant, so there is no increase in shock due to acceleration or deceleration. Moreover, since the second velocity area S2, i.e., the time integral value of the operation speed, corresponds to the travel length of the attachment tip 33F in the second operation phase PH2, the travel length of the attachment tip 33F can be kept constant without increasing the shock due to acceleration or deceleration, while responding to changes in the operation time according to the operator's operation.

[0054] Next, a second embodiment of the present invention will be described with reference to Figure 7.

[0055] In the first embodiment, as shown in Figure 5, in adjacent operation phases among the first to fourth operation phases PH1 to PH4, the operation speed is reduced to 0 (mm / sec) at the end of the preceding operation phase, and the operation speed of the subsequent operation phase is accelerated from 0 (mm / sec). In contrast, in the second embodiment, in at least one operation phase selected from the plurality of operation phases (in the example shown in Figure 7, the adjacent first operation phase PH1 and second operation phase PH2), the operation speed is changed in order to omit the deceleration operation of the subsequent operation phase (second operation phase PH2 in Figure 7) that follows the preceding operation phase (first operation phase PH1 in Figure 7). For example, if the transition from the first operation phase PH1 to the second operation phase PH2 does not involve a large change in the direction of the target operation trajectory, for example, if the angle corresponding to the change in direction is a small angle of a predetermined angle (e.g., 45°) or less, then changing the operating speed to transition to the second operation phase PH2 without deceleration before the end of the first operation phase PH1 will result in less shock due to the change in direction.

[0056] In such a case, when a change command for making the above change is input, the control unit 40 according to the second embodiment controls the operating speed of the first operating phase PH1 in a pair of adjacent operating phases selected as target operating phases from among the plurality of operating phases, namely the first operating phase PH1 and the second operating phase PH2 in the example shown in Figure 7. This control not only omits the deceleration operation of the second operating phase PH2, which is the subsequent operating phase, but also performs an acceleration operation that continuously (linearly in the example shown in Figure 7) changes the operating speed from the preceding constant operating speed (the preceding constant operating speed in the first operating phase PH1) to the succeeding constant operating speed (the succeeding constant operating speed in the second operating phase PH2), which is the succeeding constant operating speed. In other words, the control unit 40 controls the operating speed of the first operating phase PH1 in such a way that it performs an acceleration operation that omits only a part of the acceleration operation before the change.

[0057] However, if the above modification involves a change in the velocity area of ​​the pair of operation phases (in the example shown in Figure 7, the first and second velocity areas S1 and S2 of the first and second operation phases PH1 and PH2), that is, a change in the travel length of the attachment tip 33F, then proper movement of the attachment tip 33F becomes impossible thereafter. For example, a decrease in the travel length causes the system to move to the next second operation phase PH2 before the attachment tip 33F has completed moving along the target operation trajectory planned in the first operation phase PH1, making proper movement of the attachment tip 33F thereafter impossible.

[0058] Therefore, the control unit 40 performs speed control to perform the acceleration (or deceleration) operation while keeping the velocity area of ​​the pair of operation phases (first velocity area S1 and second velocity area S2 in Figure 7) constant. Specifically, as shown in the lower part of Figure 7, the control unit 40 increases the time of constant velocity operation in the first operation phase PH1, which is the preceding operation phase, in conjunction with the omission of the deceleration operation in the first operation phase PH1, and changes the total operation time T1 of the first operation phase PH1 to an operation time T1' that is shorter than the operation time T1. In this way, regardless of the omission of the deceleration operation in the first operation phase PH1, the control unit 40 performs speed control to keep the first velocity area S1, which is the total velocity area of ​​the first operation phase PH1, constant. On the other hand, the control unit 40 increases the time of constant velocity operation in the second operation phase PH2, which is the subsequent operation phase, in conjunction with the omission of a part of the acceleration operation in the second operation phase PH2, and changes the total operation time T2 of the second operation phase PH2 to an operation time T2' that is longer than the operation time T2, thereby performing speed control that keeps the second velocity area S2, which is the total velocity area of ​​the second operation phase PH2, constant regardless of the partial omission of the acceleration operation.

[0059] Thus, the control according to the second embodiment makes it possible to reduce wasted operating time by keeping the time integral value of the operating speed in each of the preceding and succeeding operating phases constant, while matching the travel length of the attachment tip 33F corresponding to the time integral value to the length of the target operating trajectory, and omitting at least a portion of unnecessary deceleration and acceleration operations. This control is not limited to the first and second operating phases PH1 and PH2, but can also be applied to other pairs of adjacent operating phases, such as the second operating phase PH2 and the third operating phase PH3.

[0060] The means for maintaining the velocity area (the time integral of the operating speed) constant are not limited to changing the operating time of adjacent operating phases. For example, the means may be a change in the constant velocity operating speed in at least one of the preceding operating phase and the succeeding operating phase.

[0061] Figure 8 shows a first modified example of the second embodiment. The upper part of Figure 8 shows the operating speed graph before the modification of the first modified example, and the lower part shows the operating speed graph after the modification.

[0062] The control unit 40 according to the first modified example makes changes between the adjacent second operation phase PH2 and third operation phase PH3, in addition to the changes shown in Figure 7, based on commands input to the control unit 40. Specifically, the changes include omitting the acceleration operation at the start of the subsequent operation phase, the third operation phase PH3, and omitting the deceleration operation immediately before the end of the preceding operation phase, i.e., the second preceding operation phase PH2. The command for the changes is input to the control unit 40 from the input / output device 54 or an input unit equivalent thereto when the angle corresponding to the change in direction of the target operation trajectory accompanying the transition from the second operation phase PH2 to the third operation phase PH3 is less than or equal to a predetermined angle, and the constant velocity operation speed of the second operation phase PH2 is higher than the constant velocity operation speed of the third operation phase PH3, as shown in the upper part of Figure 8. The control unit 40 performs a deceleration operation to continuously (linearly in the illustrated example) reduce the operating speed from the constant operating speed of the second operating phase PH2 to the constant operating speed of the third operating phase PH32 until the preceding operating phase, the second operating phase PH2, is completed. In other words, the control unit 40 performs control to change the operating speed so as to partially omit the deceleration operation of the second operating phase PH2.

[0063] Furthermore, in this first modified example, the control unit 40 makes the above modifications to keep the second and third velocity areas S2 and S3 of the second and third operation phases PH2 and PH3 constant. Specifically, as shown in the lower part of Figure 8, the control unit 40 performs speed control to keep the second velocity area S2, which is the velocity area of ​​the entire second operation phase PH2, constant regardless of the above modifications by increasing the time of constant velocity operation in the second operation phase PH2 and decreasing the overall operation time of the second operation phase PH2, along with omitting part of the deceleration operation in the second operation phase PH2. On the other hand, the control unit 40 performs speed control to keep the third velocity area S3, which is the velocity area of ​​the entire third operation phase PH3, constant regardless of the above modifications by increasing the time of constant velocity operation and decreasing the overall operation time of the third operation phase PH3, along with omitting the acceleration operation in the third operation phase PH3.

[0064] The aforementioned control also makes it possible to further reduce wasted operating time by omitting at least a portion of unnecessary deceleration and acceleration operations while matching the travel length of the attachment tip 33F in the second and third operating phases PH2 and PH3 to the length of the target operating trajectory.

[0065] In the first modified example, the means for keeping the second and third velocity areas S2 and S3 (time integral values) of the second and third operating phases PH2 and PH3 constant is not limited to changing the operating time, but may also be, for example, changing the constant velocity operating speed.

[0066] Figure 9 shows a second modified example of the second embodiment. The upper part of Figure 9 shows the operating speed graph before modification according to the first modified example, and the lower part shows the operating speed graph after the modification.

[0067] In the example shown in Figure 7, the deceleration operation of the first operation phase PH1 is completely omitted, whereas in the second modified example, only a part of the deceleration operation is omitted. Specifically, the first operation phase PH1 ends when the operating speed decreases from the first constant-velocity operating speed to a termination speed greater than 0, and after the start of the next second operation phase PH2, a constant-velocity operation is performed to maintain the termination speed for a predetermined time. That is, the control unit 40 in the second modified example makes a change based on the input of a command from the input / output device 54 or an input unit equivalent thereto, which omits a part of the deceleration operation of the first operation phase PH1, which is the preceding operation phase of a pair of adjacent first operation phases PH1 and second operation phases PH2, and replaces a part of the acceleration operation of the second operation phase PH2, which is the succeeding operation phase, with a constant-velocity operation at the operating speed at the end of the deceleration operation, in other words, a change is made to make the operating speed at the end of the first operation phase PH1 and the operating speed at the start of the second operation phase PH2 continuous.

[0068] Furthermore, in this second modified example, the control unit 40 makes the modifications to maintain the first and second velocity areas S1 and S2 of the first and second operation phases PH1 and PH2 at the same level as before the modifications. Specifically, as shown in the lower part of Figure 9, the control unit 40 maintains the first velocity area S1 in the first operation phase PH1 by omitting a portion of the deceleration operation in the first operation phase PH1, thereby increasing the time of constant velocity operation in the first operation phase PH1 and decreasing the overall operation time of the first operation phase PH1. On the other hand, the control unit 40 maintains the second velocity area S2 in the second operation phase PH2 by replacing a portion (start portion) of the acceleration operation in the second operation phase PH2 with constant velocity operation at the operating speed at the end of the first operation phase PH1, thereby reducing the time of constant velocity operation in the second operation phase PH2.

[0069] The aforementioned control also makes it possible to reduce wasted operating time by keeping the first and second velocity areas S1 and S2 (time integral values) constant in the first and second operating phases PH1 and PH2, and matching the travel length of the attachment tip 33F corresponding to the time integral value to the length of the target operating trajectory, while omitting some unnecessary deceleration and acceleration operations.

[0070] In the second modified example, the means for keeping the first velocity areas S1 and S2 (time integral values) of the first and second operating phases PH1 and PH2 constant is not limited to changing the operating time, but may also be, for example, changing the constant velocity operating speed.

[0071] Next, a third embodiment of the present invention will be described with reference to Figure 10. In this third embodiment, a command for changing the target operating trajectory, such as changing the length of the target operating trajectory in the target operating phase, is input to the control unit 40.

[0072] The aforementioned command is input, for example, when, in a predetermined target operating trajectory, the angle of change of direction of the attachment between the preceding operating phase and the subsequent operating phase is large, and a modification of the target operating trajectory is required to make the change of direction gentler.

[0073] Figure 10 shows the target operating trajectories before modification in the second operation phase PH2 and the third operation phase PH3 according to this third embodiment, indicated by solid arrows A2 and A3, respectively. If, as indicated by arrow A2, the target operating trajectory in the second operation phase PH2 is substantially straight and extends in a certain direction, and as indicated by arrow A3, the direction of the target operating trajectory at the start of the third operation phase PH3 changes abruptly from the direction of the target operating trajectory in the second operation phase PH2, for example, if the angle corresponding to the change in direction is greater than 45°, then a command is input to the control unit 40 by the input / output device 54 or an equivalent input unit to change at least a portion of the target operating trajectory in the second operation phase PH2 into a curve as shown by arrow A2' in Figure 10, thereby smoothly transitioning to the middle part of the third operation phase PH3.

[0074] Upon receiving the command, the control unit 40 not only changes the target operating trajectory in the second and third operating phases PH2 and PH3 as shown in Figure 10, but also controls the operating speed of the attachment so that the length of the attachment tip, which corresponds to the time integral of the operating speed in the second and third operating phases PH2 and PH3, matches the length of the target operating trajectory after the change. For example, the change shown in Figure 10 involves an increase in the length of the target operating trajectory in the second operating phase PH2 and a decrease in the length of the target operating trajectory in the third operating phase PH3. Therefore, the control unit 40 increases the time integral of the operating speed in the second operating phase PH2 by the amount of the increase in the length of the target operating trajectory, and decreases the time integral of the operating speed in the third operating phase by the amount of the decrease in the length of the target operating trajectory. Specifically, the increase or decrease of the time integral may be performed by changing the operating time of constant-velocity operation in the target operating phases, the second and third operating phases PH2 and PH3, as in the first and second embodiments, or by changing the operating speed in the constant-velocity operation. In this way, by changing the target operating trajectory, it is possible to control the operating speed appropriately while enabling smooth operation of the attachment 33.

[0075] The present invention is not limited to the embodiments described above.

[0076] For example, the work machine according to the present invention may be a manipulator of an industrial robot or something similar. In this case, the device at the tip of the manipulator that performs the action for performing the work corresponds to the attachment according to the present invention.

[0077] In the present invention, if an input unit is provided for inputting commands to the control unit, the input unit is not limited to one that inputs commands in response to operator operation, such as the input / output device 54. The input unit may be configured to automatically determine whether to make a change and input a change command to the control unit 40 when the given target operating trajectory satisfies predetermined modification conditions, for example, when, as in the first and second embodiments, it is preferable to omit at least a part of the acceleration and deceleration operations because the angle of change of direction accompanying the transition from the preceding operation phase to the succeeding operation phase is small, or conversely, when, as in the third embodiment, it is preferable to modify the target operating trajectory so that the angle of change of direction is large and a smooth transition is possible. For example, programs including the functions of the input unit and the control unit may be executed by the same or separate computers.

[0078] Furthermore, the specific content of the changes is not limited. For example, in the first and second embodiments, the command includes fixing the acceleration in the acceleration operation and the deceleration in the deceleration operation, but the control of the operating speed accompanying the changes may also involve changing the acceleration or the deceleration.

[0079] In the embodiment described above, the storage unit 42 may store the upper limit speed of constant-velocity movement in the target operation phase, and the control unit 40 may be configured to control the speed of constant-velocity movement within a range in which the speed of constant-velocity movement does not exceed the upper limit speed. For example, if the speed of constant-velocity movement calculated based on the operation time specified by the operator exceeds the upper limit speed (for example, 300 mm / s), the control unit 40 may be configured to output an alarm from the input / output device 54 or other output unit to prompt the operator to re-input the operation time.

[0080] The setting of the upper limit of the operating speed can also be applied to acceleration or deceleration operations. For example, the memory unit 42 can set the upper limit of the acceleration (for example, 100 mm / s²). ２ ), and the upper limit of the deceleration degree (for example, 100 mm / s ２ The control unit 40 may be configured to store the above values ​​and notify the operator by outputting an alarm from the output unit if the acceleration in the acceleration operation or the deceleration in the deceleration operation calculated in conjunction with the change in the target operating trajectory exceeds the upper limit.

[0081] As described above, a work machine is provided that can control an attachment in response to changes in operating speed, etc. The work machine comprises an attachment capable of performing operations for work, and a control unit that controls the movement of the attachment so that the attachment moves along a target operating trajectory. The operation of the attachment along the target operating trajectory includes a plurality of sequential operation phases. The plurality of operation phases include at least one of acceleration, constant speed, and deceleration. The control unit is configured to control the operation of the attachment in at least one target operation phase selected from the plurality of operation phases based on a time integral value, which is the value obtained by integrating the operating speed, which is the speed of the operation of the attachment, over elapsed time.

[0082] Specifically, it is preferable that the work machine further includes an input unit for inputting a change command for a change in at least one target operation phase to the control unit, and that the control unit is configured to perform the change when the change command is input and to control the operation of the attachment in the target operation phase so that the movement length of the attachment corresponding to the time integral value approaches the length of the target operation trajectory in the target operation phase after the change.

[0083] For example, the target operation phase includes at least one of the acceleration operation and the deceleration operation and the constant velocity operation, the change command is a command for changing the operation time required to execute the target operation phase, and the control unit may be configured to increase or decrease the operating speed of the constant velocity operation from the operating speed before the change, so as to keep the time integral value constant regardless of the change in operation time, when the change command is input.

[0084] The input unit may be configured to input a fix command to the control unit in addition to the change command. The fix command includes at least one of the following: a command to fix the acceleration of the acceleration operation in the target operation phase, a command to fix the operating speed of the constant-velocity operation, and a command to fix the deceleration of the deceleration operation. In this case, it is preferable that the control unit is configured to control the operating speed of the acceleration operation, the constant-velocity operation, and the deceleration operation that are not subject to the fix command, so as to keep the time integral value constant regardless of the change, when the change command and the fix command are input.

[0085] The at least one target operation phase includes a preceding operation phase and a subsequent operation phase, the preceding operation phase and the subsequent operation phase each include constant-velocity operations with different operating speeds, and the change command may be a command for a change to provide an acceleration operation or a deceleration operation to at least one of the preceding operation phase and the subsequent operation phase to continuously change the operating speed from the operating speed of the constant-velocity operation in the preceding operation phase to the operating speed of the constant-velocity operation in the subsequent operation phase. In this case, it is preferable that the control unit is configured to control the operating speed in each of the preceding operation phase and the subsequent operation phase so as to keep the time integral value in each of the preceding operation phase and the subsequent operation phase constant, regardless of the change.

[0086] The change command may also be a command for changing the target operating trajectory such that the length of the target operating trajectory changes during the target operating phase. When such a change command is input, it is preferable that the control unit controls the operation of the attachment so that the length of the attachment's movement corresponding to the time integral value matches the length of the target operating trajectory after the change.

Claims

1. A work machine comprising: an attachment capable of performing actions for work; and a control unit that controls the actions of the attachment so that the attachment moves along a target action trajectory, wherein the actions of the attachment along the target action trajectory include a plurality of sequential action phases, the plurality of action phases include at least one of acceleration, constant velocity, and deceleration, and the control unit is configured to control the actions of the attachment in the target action phase based on a time integral value which is the value obtained by integrating the speed of the actions of the attachment over elapsed time in at least one target action phase selected from the plurality of action phases.

2. A work machine according to claim 1, further comprising an input unit for inputting a change command for a change in at least one target operation phase to the control unit, wherein the control unit performs the change when the change command is input and controls the operation of the attachment in the target operation phase so that the length of the attachment's movement corresponding to the time integral value approaches the length of the target operation trajectory in the target operation phase after the change.

3. A work machine according to claim 2, wherein the target operation phase includes at least one of the acceleration operation and the deceleration operation and the constant velocity operation, the change command is a command for changing the operation time required to execute the target operation phase, and the control unit is configured, when the change command is input, to increase or decrease the operating speed of the constant velocity operation from the operating speed before the change so as to keep the time integral value constant regardless of the change in operation time.

4. A work machine according to claim 2 or 3, wherein the input unit is configured to input a fix command in addition to the change command to the control unit, the fix command includes at least one of a command to fix the acceleration of the acceleration operation in the target operation phase, a command to fix the operating speed of the constant-velocity operation, and a command to fix the deceleration of the deceleration operation, and the control unit is configured to control the operating speed of the acceleration operation, the constant-velocity operation, and the deceleration operation that is not subject to the fix command, so as to keep the time integral value constant regardless of the change when the change command and the fix command are input.

5. A work machine according to claim 2, wherein the at least one target operation phase includes a preceding operation phase and a subsequent operation phase, the preceding operation phase and the subsequent operation phase each include constant-velocity operations with different operating speeds, the change command is a command for a change to give the acceleration operation or deceleration operation to at least one of the preceding operation phase and the subsequent operation phase to continuously change the operating speed from the operating speed of the constant-velocity operation in the preceding operation phase to the operating speed of the constant-velocity operation in the subsequent operation phase, and the control unit is configured to control the operating speed in each of the preceding operation phase and the subsequent operation phase to keep the time integral value in each of the preceding operation phase and the subsequent operation phase constant regardless of the change.

6. A work machine according to claim 2, wherein the change command is a command for changing the target operating trajectory such that the length of the target operating trajectory in the target operating phase changes, and the control unit controls the operation of the attachment such that, when the change command is input, the length of the attachment's movement corresponding to the time integral value matches the length of the target operating trajectory after the change.

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