Work machine control method and work machine

Abstract

To solve the problem that a state where the attitude of an operation part cannot be changed in a first direction continues indefinitely when regulation control for regulating the attitude change of the operation part in the first direction is not released.SOLUTION: After the operation part automatically stops at the stop position, executing regulation control for regulating a change in a posture of the operation part in a first direction, and when the operation part reaches a first specific position set on a side in a second direction from the stop position and a predetermined regulation release condition is satisfied, and stopping the regulation control being executed when the operation part reaches a second specific position set on the second direction side of the first specific position in a case where the regulation release condition is not satisfied.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a control method for a work machine and a work machine. [Background technology]

[0002] BACKGROUND ART Conventionally, there is known a work vehicle that restricts the rotation of a work device (for example, an arm) so that the work device does not rotate toward the approach side when the rotation of the work device stops within a restricted range (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-40436 Summary of the Invention [Problem to be solved by the invention]

[0004] When the arm rotates and reaches a predetermined position (specific position) and a predetermined release condition is satisfied, the rotation restriction (restriction control) is released, allowing the arm to rotate toward the approach side, i.e., in a first direction toward the driving unit. On the other hand, if the predetermined release condition is not satisfied, the restriction control is not released, and the arm cannot rotate in the first direction. For example, if the posture change caused by the arm rotation is a special posture change, such as a very slow one, the restriction control may not be released because the predetermined release condition is not satisfied. If the restriction control continues when the predetermined release condition is not satisfied, the arm will never be able to rotate in the first direction.

[0005] The present invention has been made to solve the above problems, and its object is to provide a control method for a work machine and a work machine that can eliminate the inconvenience of a state in which the attitude of an operating part, such as an arm, cannot be changed in the first direction indefinitely when restriction control that restricts the change in attitude of the operating part in a first direction toward the driving part is not released. [Means for solving the problem]

[0006] A control method for a work machine according to one aspect of the present invention is a control method for a work machine equipped with an actuator that changes its posture in a first direction toward a driving unit and a second direction away from the driving unit, the control method automatically stopping the actuator at a predetermined stop position and allowing the posture of the actuator to change from the stop position in the second direction, the control method comprising the steps of: executing a restriction control to restrict the change in posture of the actuator in the first direction after the actuator has automatically stopped at the stop position; stopping the restriction control that is being executed when the actuator reaches a first specific position set on the second direction side from the stop position and satisfies a predetermined restriction release condition; and stopping the restriction control that is being executed when the actuator reaches a second specific position set on the second direction side of the first specific position if the restriction release condition is not satisfied.

[0007] A work machine according to another aspect of the present invention is a work machine comprising: a driving unit; an operating unit that changes its posture in a first direction toward the driving unit and a second direction away from the driving unit; and a control unit that automatically stops the operating unit at a predetermined stop position and controls the operating unit to allow a change in posture from the stop position in the second direction, wherein the control unit executes a restriction control that restricts a change in posture of the operating unit in the first direction after the operating unit has automatically stopped at the stop position, stops the restriction control that is being executed when the operating unit reaches a first specific position set on the second direction side from the stop position and satisfies a predetermined restriction release condition, and if the restriction release condition is not satisfied, stops the restriction control that is being executed when the operating unit reaches a second specific position set on the second direction side of the first specific position. [Effects of the Invention]

[0008] This eliminates the inconvenience of the state in which the attitude of the operating part cannot be changed in the first direction indefinitely when the restriction control that restricts the attitude change of the operating part in the first direction is not released. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a side view showing a schematic configuration of a hydraulic excavator, which is an example of a work machine according to the present invention. [Figure 2] FIG. 2 is an explanatory diagram schematically illustrating a hydraulic circuit related to driving the arm. [Figure 3] 10 is a flowchart showing a flow of restricting and releasing the rotation of the arm. [Figure 4] FIG. 10 is an explanatory diagram schematically illustrating a state in which the arm is stopped at a predetermined stop position. [Figure 5] 10 is an explanatory diagram schematically showing a state in which the arm automatically stops at a stop position, then rotates in a second direction, and passes beyond a first specific position. FIG. [Figure 6] 10 is an explanatory diagram schematically showing a state in which the arm has further rotated in a second direction and passed the first specific position, and showing the rotatable directions at that time. FIG. [Figure 7] 10 is an explanatory diagram schematically illustrating a threshold value of the angular velocity of the arm and a predetermined time period. FIG. [Figure 8] 10 is a graph schematically showing an example of a change in the angular velocity of the arm. [Figure 9] 10 is a graph schematically showing another example of a change in the angular velocity of the arm. [Figure 10] 10 is an explanatory diagram showing a state in which the arm has passed the first specific position and showing the rotatable directions at that time. FIG. [Figure 11] 10 is a graph schematically showing yet another example of a change in the angular velocity of the arm. [Figure 12] 10 is a graph schematically showing yet another example of a change in the angular velocity of the arm. [Figure 13] FIG. 10 is an explanatory diagram schematically showing a state in which the arm has reached a second specific position. [Figure 14] FIG. 4 is a side view showing another configuration of the hydraulic excavator. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes an embodiment of the present invention with reference to the drawings.

[0011] [1. Work Machinery] 1 is a side view showing a schematic configuration of a hydraulic excavator 1, which is an example of a work machine according to this embodiment. The hydraulic excavator 1 includes a lower traveling structure 2, a work implement 3, and an upper rotating structure 4.

[0012] In this specification, directions are defined as follows: The direction in which the operator (operator, driver) seated in the driver's seat 41a of the upper rotating body 4 faces forward is defined as the forward direction, and the opposite direction is defined as the rearward direction. Therefore, when the upper rotating body 4 is not rotating relative to the undercarriage 2 (swing angle 0°), the fore-and-aft direction of the upper rotating body 4 coincides with the direction in which the undercarriage 2 moves forward and backward. Furthermore, the left side as seen from the operator seated in the driver's seat 41a is defined as the "left," and the right side is defined as the "right." Furthermore, the direction of gravity, which is perpendicular to the fore-and-aft direction and the left-and-right direction, is defined as the up-and-down direction, with the upstream side of the direction of gravity defined as the "up" and the downstream side as the "down." In the drawings, the hydraulic excavator 1 is shown in a state in which the upper rotating body 4 is not rotating relative to the undercarriage 2. In the drawings, the forward direction is defined as "F," the rearward direction as "B," the upward direction as "U," and the downward direction as "D."

[0013] The lower traveling structure 2 includes a pair of left and right crawlers 21 and a pair of left and right traveling motors 22. Each traveling motor 22 is a hydraulic motor. The left and right traveling motors 22 drive the left and right crawlers 21, respectively, thereby moving the hydraulic excavator 1 forward and backward. The lower traveling structure 2 further includes a blade 23 for performing ground leveling work, and a blade cylinder (not shown) that rotates the blade 23 up and down.

[0014] The work implement 3 includes a boom 31, an arm 32, and a bucket 33. By independently driving the boom 31, the arm 32, and the bucket 33, it is possible to perform excavation work for earth and sand, etc. Furthermore, instead of the bucket 33, an attachment can be attached as appropriate. For example, if a breaker is attached as an attachment, it is possible to perform crushing or demolition work using the breaker.

[0015] The boom 31, the arm 32, and the bucket 33 are driven by a boom cylinder 31a, an arm cylinder 32a, and a bucket cylinder 33a, respectively. The boom cylinder 31a, the arm cylinder 32a, and the bucket cylinder 33a are configured by hydraulic cylinders.

[0016] The base end of the boom 31, i.e., the end of the boom 31 opposite the side connected to the arm 32, is swingably connected to the tip end 42a of the revolving frame 42 via a boom bracket 421. That is, the hydraulic excavator 1 of this embodiment has a boom swing function in which the boom 31 swings left and right from the tip end 42a as a starting point. The revolving frame 42 is provided with a swing cylinder 42b. The swing cylinder 42b is formed by a hydraulic cylinder, and swings the boom 31 by extending and retracting.

[0017] The boom 31 has a shape that is bent forward at an obtuse angle, and is rotated up and down by the extension and retraction of the boom cylinder 31a. The boom cylinder 31a is located forward of the boom 31. The base end of the boom cylinder 31a is supported by the boom bracket 421, and the tip end is connected to the bent portion of the boom 31 so as to move telescopically. The arm 32 is rotatably connected to the tip end of the boom 31. The arm 32 is rotated in the front-rear direction by the extension and retraction of the arm cylinder 32a. The base end of the arm cylinder 32a is supported by the boom 31, and the tip end is connected to the base end of the arm 32 so as to move telescopically. The bucket 33 is connected to the tip end of the arm 32 via a link mechanism 34, and is rotated in the front-rear direction by the extension and retraction of the bucket cylinder 33a. The base end of the bucket cylinder 33a is supported by the arm 32, and the tip end is connected to the link mechanism 34 so as to move telescopically.

[0018] The upper rotating body 4 is located above the lower traveling body 2 and is provided so as to be able to rotate relative to the lower traveling body 2. A driving unit 41, a rotating frame 42, a rotating motor 43, and a machine room 44 are arranged on the upper rotating body 4. The upper rotating body 4 rotates via a rotating bearing (not shown) by driving the rotating motor 43, which is a hydraulic motor. Inside the machine room 44, multiple hydraulic pumps are arranged in addition to the engine 40 that provides power to each part.

[0019] Each hydraulic pump supplies hydraulic oil (pressurized oil) to a hydraulic motor (for example, the left and right travel motors 22, the swing motor 43) and a hydraulic cylinder via hydraulic piping. The hydraulic cylinders include the above-mentioned blade cylinder as well as the boom cylinder 31a, the arm cylinder 32a, and the bucket cylinder 33a. The above-mentioned hydraulic motors and hydraulic cylinders that are driven by the supply of hydraulic oil from any hydraulic pump are collectively called hydraulic actuators.

[0020] The driving section 41 is provided above the machine room 44. A driving seat 41a is arranged in the driving section 41. Various operating levers 41b are arranged around the driving seat 41a. When an operator sits on the driving seat 41a and operates the operating levers 41b, predetermined hydraulic actuators are driven.

[0021] The driver's section 41 includes a canopy 45. The canopy 45 is erected at the rear upper part of the engine room 44 and covers at least the area above the driver's seat 41a. Note that a cabin may be provided instead of the canopy 45. The cabin has a door that opens and closes when the operator gets on and off the vehicle, and covers not only the area above the driver's seat 41a but also the areas around the driver's seat 41a on the front, back, left, and right sides.

[0022] [2. Configuration for restricting arm rotation] As described above, the hydraulic excavator 1 serving as a work machine in this embodiment includes a driving unit 41 and a work implement 3. In the example of FIG. 1, the work implement 3 is disposed in front of the driving unit 41. The work implement 3 includes an arm 32 serving as an actuating unit. As described above, the arm 32 is rotatably connected to the tip of the boom 31. This allows the arm 32 to change its posture by rotating in a first direction D1 toward the driving unit 41 and in a second direction D2 away from the driving unit 41. Note that in the example of FIG. 1, the first direction D1 can also be said to be rearward, and the second direction D2 can also be said to be forward.

[0023] In this embodiment, the rotation of the arm 32 is restricted and released (stopped), as described below, depending on the rotation position and rotation state of the arm 32. First, a configuration for restricting and releasing the rotation will be described.

[0024] 2 is an explanatory diagram that schematically shows a hydraulic circuit involved in driving the arm 32. The hydraulic excavator 1 includes an arm angle sensor 50 and a controller 60. The arm angle sensor 50 is attached to the arm 32 and detects the rotation angle (rotation position) of the arm 32. The arm angle sensor 50 is configured with, for example, a potentiometer, but may also be configured with other sensors such as an inertial measurement unit (IMU).

[0025] The controller 60 is an electronic control unit also known as an ECU (Electronic Control Unit), and is a control section that electrically controls each section of the hydraulic excavator 1. In particular, the controller 60 outputs a control signal to the solenoid valve SV based on an angle detection signal from the arm angle sensor 50, switching the solenoid valve SV on and off. The solenoid valve SV is disposed in a pilot oil passage between the remote control valve RV, which is linked to the operation lever 41b (see FIG. 1), and the control valve CV. The hydraulic circuit will be described in more detail below.

[0026] The control valve CV is an assembly of directional control valves corresponding to the hydraulic actuators, and therefore includes a directional control valve corresponding to the arm cylinder 32a.

[0027] The directional control valve corresponding to the arm cylinder 32a has two input ports. Two remote control valves RV are provided corresponding to the two input ports. When the operation lever 41b (for example, the left operation lever) is tilted forward to perform a dump operation, pilot oil is output from one remote control valve RV (hereinafter also referred to as the first remote control valve) to one input port (hereinafter also referred to as the first input port) of the directional control valve. This opens an opening in the directional control valve that is connected to the rod side of the arm cylinder 32a, and hydraulic oil discharged from the hydraulic pump P is supplied to the rod side of the arm cylinder 32a. As a result, the arm cylinder 32a contracts, and a dump operation is performed. In other words, the arm 32 rotates in the direction D2 in FIG. 1.

[0028] On the other hand, when the operation lever 41b is tilted backward to perform the crowding operation, pilot oil is output from the other remote control valve RV (hereinafter also referred to as the second remote control valve) to the other input port (hereinafter also referred to as the second input port) of the directional control valve. This opens an opening in the directional control valve that is connected to the bottom side of the arm cylinder 32a, and hydraulic oil is supplied to the bottom side of the arm cylinder 32a. As a result, the arm cylinder 32a extends, and the crowding operation is performed. In other words, the arm 32 rotates in the D1 direction in FIG. 1.

[0029] The above-mentioned solenoid valve SV is provided in a pilot oil passage between the second port of the directional control valve and the second remote control valve. Therefore, when the controller 60 energizes the solenoid valve SV to turn it ON, the solenoid valve SV cuts off the supply of pilot oil from the second remote control valve to the second port of the directional control valve. As a result, hydraulic oil is no longer supplied to the bottom side of the arm cylinder 32a, and rotation (winding) of the arm 32 in the D1 direction is automatically stopped. In other words, rotation of the arm 32 in the D1 direction is restricted. On the other hand, when the controller 60 turns off the solenoid valve SV, as described above, pilot oil is supplied from the second remote control valve to the second port of the directional control valve, and hydraulic oil is supplied to the bottom side of the arm cylinder 32a, enabling crowding of the arm 32. In other words, restriction on rotation of the arm 32 in the D1 direction is released.

[0030] [3. Control of arm rotation restriction and restriction release] 3 is a flowchart showing the flow of restricting and releasing the rotation of the arm 32 in this embodiment. The procedure of restricting and releasing the rotation of the arm 32 in this embodiment will be described below with reference to FIGS.

[0031] FIG. 4 is an explanatory diagram schematically illustrating a state in which the arm 32 is stopped at a predetermined stop position P0. Here, the stop position P0 is a position that is set in advance to automatically stop the arm 32, and is set corresponding to a predetermined rotation position (rotation angle) of the arm 32. The stop position P0 may be set by an operator through an operation unit (not shown), or by a person other than the operator (e.g., a manufacturer). Information about the stop position P0 (e.g., the corresponding rotation angle of the arm 32) may be stored in a memory built into the controller 60 or in a storage unit external to the controller 60. In FIG. 4 and subsequent drawings, for convenience, the rotation fulcrum when the boom 31 rotates relative to the boom bracket 421 (see FIG. 1) is indicated by reference numeral 310. The rotation fulcrum when the arm 32 rotates relative to the boom 31 is indicated by reference numeral 320. The rotation fulcrum when the bucket 33 (see FIG. 1) rotates relative to the arm 32 via the link mechanism 34 is indicated by reference numeral 330.

[0032] First, the controller 60 monitors whether the arm 32 has rotated in the first direction D1 and reached the stop position P0, based on a detection signal from the arm angle sensor 50. Then, when the arm 32 reaches the stop position P0, the controller 60 automatically stops the arm 32. Specifically, the controller 60 outputs a control signal to the solenoid valve SV shown in FIG. 2 to turn on the solenoid valve SV, thereby automatically stopping the arm 32 at the stop position P0. When the arm 32 automatically stops (S1), the controller 60 starts a restriction control to restrict the rotation (change in posture) of the arm 32 in the first direction D1 (S2). In other words, the controller 60 keeps the solenoid valve SV in the ON state, preventing the arm 32 from rotating from the stop position P0 in the first direction D1.

[0033] After the arm 32 automatically stops at the stop position P0, the controller 60 performs the above-described restriction control while also performing control to allow a change in the posture of the arm 32 from the stop position P0 in the second direction D2. That is, when the controller 60 determines, based on the detection signal from the arm angle sensor 50, that the arm 32 will rotate in the second direction D2, it outputs a control signal to the solenoid valve SV to turn off the solenoid valve SV. This makes it possible to rotate the arm 32 in the second direction D2. That is, it becomes possible to move the tip (bucket 33 side) of the arm 32 forward away from the boom 31.

[0034] 5 is an explanatory diagram schematically illustrating a state in which the arm 32 rotates in the second direction D2 after automatically stopping at the stop position P0 and passes the first specific position P1. The first specific position P1 is a position that is set in advance on the second direction D2 side of the stop position P0, and is set corresponding to a predetermined rotation position (rotation angle) of the arm 32. The setting of the first specific position P1 is performed by an operator or the like, similar to the setting of the stop position P0. Information on the first specific position P1 (e.g., the corresponding rotation angle of the arm 32) may be stored in a memory within the controller 60 or an external storage unit. Within a restricted range in which the arm 32 rotates in the second direction D2 from the stop position P0 and reaches the first specific position P1, rotation of the arm 32 in the first direction D1 is restricted, while rotation in the second direction D2 is permitted.

[0035] As described above, in the hydraulic excavator 1 and control method of this embodiment, after the arm 32 automatically stops at the stop position P0, the controller 60 executes restriction control to restrict changes in the position of the arm 32 in the first direction D1 (see S1 and S2). Such restriction control of the arm 32 prevents the arm 32 from rotating in the first direction D1 beyond the stop position P0. This reduces the risk that the bucket 33 connected to the tip of the arm 32 via the link mechanism 34 will come into contact with the boom cylinder 31a (see FIG. 1) located in front of the boom 31, causing damage to the boom cylinder 31a. In other words, safety that prevents damage to equipment can be ensured.

[0036] 6 is an explanatory diagram schematically illustrating a state in which the arm 32 has further rotated in the second direction D2 and passed the first specific position P1. When the arm 32 reaches the first specific position P1, the controller 60 determines whether the restriction release condition is satisfied (S3). If the restriction release condition is satisfied in S3, the controller 60 releases the restriction control (S5). That is, when the operating lever 41b is operated to rotate the arm 32 in the first direction D1, the controller 60 outputs a control signal to the solenoid valve SV to turn off the solenoid valve SV. This makes it possible to rotate the arm 32 in the first direction D1 by operating the operating lever 41b.

[0037] Here, the restriction release conditions include a first release condition and a second release condition. The first release condition is that the arm 32 is positioned closer to the second direction D2 than the first specific position P1. The second release condition is that the arm 32 has performed an action (here, a rotational action) that changes its posture in the second direction D2. The controller 60 determines that the restriction release condition is satisfied when both the first release condition and the second release condition are satisfied. On the other hand, the controller 60 determines that the restriction release condition is not satisfied when at least one of the first release condition and the second release condition is not satisfied.

[0038] Whether the first release condition is satisfied can be determined by the controller 60 based on the detection signal from the arm angle sensor 50. That is, the controller 60 determines whether the rotation angle of the arm 32 exceeds the angle corresponding to the first specific position P1 in the second direction D2. In this way, it is possible to determine whether the first release condition is satisfied.

[0039] On the other hand, whether the second release condition is satisfied is determined by the controller 60 using a threshold value Th (rad / s) of the angular velocity ω of the arm 32 and a predetermined time T0 (s) as follows: The angular velocity ω of the arm 32 refers to the angle by which the arm 32 rotates per unit time (here, 1 second). The controller 60 can calculate the angular velocity ω based on the detection signal (rotation angle information of the arm 32) from the arm angle sensor 50 and the time.

[0040] FIG. 7 is an explanatory diagram schematically illustrating the threshold value Th of the angular velocity ω of the arm 32 and the predetermined time T0. FIG. 8 is a graph schematically illustrating an example of a change in the angular velocity ω of the arm 32. In this embodiment, the controller 60 determines that the second release condition is satisfied if the time Ta during which the angular velocity ω of the arm 32 is equal to or greater than the threshold value Th during the predetermined time T0 is equal to or greater than a predetermined percentage. Here, the predetermined percentage can be, for example, 5 / 8, but can be set arbitrarily. As shown in FIG. 8, if the change in the angular velocity ω of the arm 32 during the predetermined time T0 satisfies Ta≧(5 / 8)×T0, the controller 60 determines that the second release condition is satisfied. In this case, the above-described restriction control is released at time t2, which is the elapse of the predetermined time T0 from time t1, provided that the first release condition is satisfied.

[0041] Note that the above-mentioned time Ta does not have to be a continuous time. Fig. 9 is a graph schematically showing another example of a change in the angular velocity ω of the arm 32. As shown in Fig. 9, the time Ta may be the sum of time Tb and time Tc which are separated in time. Note that both time Tb and time Tc are times during which the angular velocity ω of the arm 32 is equal to or greater than the threshold value Th within the predetermined time T0.

[0042] On the other hand, if the restriction release condition is not satisfied in S3, the controller 60 continues the restriction control. Therefore, as shown in FIG. 10, even after the arm 32 rotates in the second direction D2 and reaches the first specific position P1, the arm 32 remains unable to rotate in the first direction D1. Note that when the arm 32 reaches the first specific position P1 and further rotates in the second direction D2, the first release condition is automatically satisfied. Therefore, the case where the restriction release condition is not satisfied after the arm 32 reaches the first specific position P1 particularly means that the second release condition is not satisfied.

[0043] Examples of cases in which the second release condition is not satisfied include the following. FIGS. 11 and 12 are graphs showing examples of changes in the angular velocity ω of the arm 32 during rotation when it is determined that the second release condition is not satisfied. As shown in FIG. 11, even if the arm 32 reaches the first specific position P1 at time t1, if the angular velocity ω is less than the threshold value Th and this state continues, the second release condition is not satisfied. Also, as shown in FIG. 12, even if the angular velocity ω is equal to or greater than the threshold value Th when the arm 32 reaches the first specific position P1 at time t1, the second release condition is not satisfied if the total time Ta during which the angular velocity ω is equal to or greater than the threshold value Th during the predetermined time T0 is less than a predetermined percentage (e.g., less than 5 / 8) of the predetermined time T0. The example in FIG. 11 corresponds to a case in which the arm 32 rotates at a very slow speed. The example in FIG. 12 corresponds to an operation in which the arm 32 is rotated in small increments, that is, an operation in which the arm 32 rotates and stops repeatedly at a relatively short period (also called inching).

[0044] If the restriction release condition is not satisfied in S3, the controller 60 determines whether the arm 32 has rotated in the second direction D2 and reached a second specific position P2 (see FIG. 13), which is a restriction release position, based on a detection signal from the arm angle sensor 50 (S4). FIG. 13 is an explanatory diagram schematically illustrating a state in which the arm 32 has rotated and reached the second specific position P2. As shown in the figure, the second specific position P2 is a position that is set in advance closer to the second direction D2 than the first specific position P1, and is set corresponding to a predetermined rotation position (rotation angle) of the arm 32. The second specific position P2 is set by an operator or the like, similar to the setting of the stop position P0 and the first specific position P1. Information about the second specific position P2 (e.g., the corresponding rotation angle of the arm 32) may be stored in a memory within the controller 60 or in an external storage unit.

[0045] If it is determined in S4 that the arm 32 has reached the second specific position P2, the controller 60 forcibly releases the restriction control that has been ongoing (S5). This allows the arm 32 to be rotated in the first direction D1 by operating the operating lever 41b. Note that in FIGS. 11 and 12, the times at which the arm 32 reaches the second specific position P2 and the restriction control is released are indicated by t3 and t4, respectively. On the other hand, if it is determined in S4 that the arm 32 has not reached the second specific position P2, the process returns to S3, where it is determined again whether the restriction release condition is satisfied. From S3 onwards, the same processing as above is carried out.

[0046] As described above, the control method for the hydraulic excavator 1 of this embodiment includes stopping the ongoing restriction control when the arm 32 serving as the operating unit reaches a first specific position P1 set in the second direction D2 from the stop position P0 and satisfies a predetermined restriction release condition (see S3 and S5), and stopping the ongoing restriction control when the arm 32 reaches a second specific position P2 set in the second direction D2 from the first specific position P1 if the restriction release condition is not satisfied (see S3, S4, and S5). Furthermore, the controller 60 serving as the control unit stops the ongoing restriction control when the arm 32 reaches the first specific position P1 from the stop position P0 and satisfies the predetermined restriction release condition, and stops the ongoing restriction control when the arm 32 reaches the second specific position P2 if the restriction release condition is not satisfied.

[0047] Because the posture change caused by the rotation of the arm 32 is a special change as shown in FIGS. 11 and 12 , even if the restriction release condition is not satisfied when the arm 32 passes the first specific position P1 in the second direction D2 and the restriction control is continued, the restriction control is stopped when the arm 32 reaches the second specific position P2. This makes it possible to rotate the arm 32 from the second specific position P2 in the first direction D1. This eliminates the inconvenience of the arm 32 being unable to rotate in the first direction D1 for an extended period of time because the restriction control condition is not satisfied. In other words, the control method of this embodiment can appropriately respond to a posture change of the arm 32 that does not satisfy the restriction release condition (especially the second release condition), and makes it possible to rotate the arm 32 in the first direction D1 at a predetermined position (the second specific position P2).

[0048] In this embodiment, after it is determined in S3 that the predetermined restriction release condition is not satisfied, the process of S3, i.e., whether the restriction release condition is satisfied, is repeated until it is determined in S4 that the arm 32 has reached the second specific position P2 (if the results of S3 and S4 are No). If the restriction release condition is satisfied when the arm 32 is located between the first specific position P1 and the second specific position P2, it is no longer necessary to maintain the rotation restriction. In this regard, it is desirable for the controller 60 to perform the following control. That is, it is desirable for the controller 60 to stop the ongoing restriction control when the restriction release condition is satisfied when the arm 32 as the operating unit is located between the first specific position P1 and the second specific position P2. In other words, it is desirable for the control method of this embodiment to further include the controller 60 performing the above control. Note that the processing order at this time is S3, S4, S3, and S5.

[0049] The minimum condition for releasing the restriction control is that the arm 32 has passed the first specific position P1 in the second direction D2. Therefore, it is desirable that the restriction release condition include such a minimum condition. In other words, it is desirable that the restriction release condition include, as a first release condition, that the arm 32 is positioned further toward the second direction D2 than the first specific position P1.

[0050] When releasing the restriction control, if it is possible to confirm whether or not there has been an extension motion of the arm 32 in the second direction D2, it is possible to know that the arm 32 is away from the driving unit 41 and that it is safe to release the restriction control, and therefore it is more appropriate to include this as a condition for releasing the restriction. In other words, from the perspective of more appropriately releasing the restriction control, it is desirable that the restriction release conditions include, as a second release condition, that the arm 32 has performed an action to change its posture in the second direction D2.

[0051] Furthermore, in order to detect that the arm 32 has performed an operation to change its posture in the second direction D2, it is desirable to monitor a change in the rotation speed per unit time of the arm 32. In this regard, it is desirable to set the second release condition based on the angular velocity ω and time t during rotation of the arm 32. More desirably, the second release condition is that the time during which the angular velocity ω of the arm 32 is equal to or greater than the threshold value Th is equal to or greater than a predetermined percentage.

[0052] In the hydraulic excavator 1 of this embodiment, the work machine 3 includes a boom 31 that rotatably supports an arm 32 serving as an operating unit. In the control of this embodiment, from the viewpoint of enabling accurate and precise determination of whether the rotating arm 32 has reached the stop position P0, the first specific position P1, and the second specific position P2, it is desirable that the stop position P0, the first specific position P1, and the second specific position P2 be set so as to correspond to different rotation positions (rotation angles) of the arm 32.

[0053] In this embodiment, the change in the posture of the arm 32 as the actuating unit in the first direction D1 is a backward rotation. Also, the change in the posture of the arm 32 in the second direction D2 is a forward rotation. In this manner, the effect of this embodiment can be obtained by applying the control method of this embodiment described above to a configuration in which the posture of the actuating unit changes due to the rotation of the arm 32 in the forward and backward directions.

[0054] [4. Other configurations of hydraulic excavators] The above-mentioned operating unit is not limited to the arm 32 that rotates in the front-rear direction. Fig. 14 is a side view showing another configuration of the hydraulic excavator 1. The hydraulic excavator 1 in Fig. 14 is configured such that the work implement 3 is supported on the right side of the driving unit 41 in the upper rotating body 4. Note that the driving unit 41 is of a cabin specification in which a cabin 46 is provided instead of the canopy 45 in Fig. 1, but it may remain of a canopy specification.

[0055] The boom 31 of the work implement 3 shown in FIG. 14 has a first boom 311, a second boom 312, and a third boom 313. The first boom 311 is supported by the upper rotating body 4 so as to be rotatable in the front-to-rear direction. The second boom 312 is supported so as to be rotatable in the left-to-right direction relative to the first boom 311. The third boom 313 is supported so as to be rotatable in the left-to-right direction relative to the second boom 312. The arm 32 is supported so as to be rotatable in the front-to-rear direction relative to the third boom 313. In other words, in the work implement 3 configured as described above, the arm 32 can be displaced (offset) in the left-to-right direction by rotating the third boom 313 in the left-to-right direction via the second boom 312. Except for the above, the hydraulic excavator 1 in FIG. 14 has the same configuration as the hydraulic excavator 1 shown in FIG. 1.

[0056] In a hydraulic excavator 1 having an offset-type work implement 3, when the boom 31 is offset to the left, there is a risk that any of the second boom 312, the arm 32, or the bucket 33 will come into contact with the driver's unit 41. For this reason, the risk of the work implement 3 coming into contact with the driver's unit 41 is reduced by automatically stopping the leftward positional change of the boom 31 at a predetermined stop position. Therefore, the control of restricting and releasing the rotation of the arm 32 described in this embodiment can also be applied to a hydraulic excavator 1 having such an offset-type work implement 3. In this case, the actuating unit is configured by a part of the boom 31 (for example, the second boom 312). Furthermore, a first direction D1 in which the actuating unit approaches the driver's unit 41 is the left, and a second direction D2 in which the actuating unit moves away from the driver's unit 41 is the right.

[0057] [5. About the Program] The controller 60 provided in the hydraulic excavator 1 of this embodiment can be configured as a computer on which an operating program (application software) is installed. The computer (controller 60) reads and executes the program, thereby realizing each process according to the control method of this embodiment. Such a program may be obtained, for example, by downloading it from an external source via a network, or by reading the program from a computer-readable recording medium such as a CD-ROM (Compact Disk-Read Only Memory) on which the program is recorded.

[0058] [6. Supplementary Information] In the present embodiment, an example has been described in which the restriction control is started after the arm 32 automatically stops at the stop position P0, but the trigger for starting the restriction control is not limited to the automatic stopping of the arm 32 at the stop position P0. For example, the restriction control may be started when the arm 32 is manually stopped at a position other than the stop position P0 within the restriction range between the stop position P0 and the first specific position P1.

[0059] The hydraulic excavator 1 may be configured to use hydraulic equipment such as hydraulic actuators (e.g., hydraulic motors and hydraulic cylinders) in combination with electrically driven actuators. Electrically driven actuators include, for example, electric travel motors, electric cylinders, and electric swing motors.

[0060] In this embodiment, a hydraulic excavator 1, which is a construction machine, has been described as an example of the work machine, but the work machine is not limited to the hydraulic excavator 1 and may be other construction machines such as a wheel loader, a compact track loader, etc. Furthermore, the work machine may be agricultural machinery such as a combine harvester, a tractor, etc.

[0061] The hydraulic excavator 1 is configured to include an engine 40 (see FIG. 1) as a prime mover, but the prime mover may also be an electric motor.

[0062] [7. Notes] The work machine control method and work machine described in this embodiment can be expressed as follows.

[0063] The control method for the work machine in Appendix (1) is as follows: A control method for a work machine having an actuator that changes its posture in a first direction toward a driving unit and in a second direction away from the driving unit, the control method automatically stops the actuator at a preset stop position and allows the posture of the actuator to change from the stop position in the second direction, comprising: After the operating unit automatically stops at the stop position, executing a restriction control to restrict a change in the attitude of the operating unit in the first direction; stopping the restriction control that is being executed when the operation unit reaches a first specific position set on the second direction side from the stop position and satisfies a predetermined restriction release condition; and If the restriction release condition is not satisfied, the restriction control being executed is stopped when the operating unit reaches a second specific position set on the second direction side of the first specific position.

[0064] A control method for a work machine according to supplementary note (2) is the control method according to supplementary note (1), If the restriction release condition is satisfied when the operating portion is located between the first specific position and the second specific position, the restriction control being executed is stopped.

[0065] The control method for a work machine according to supplementary note (3) is the control method according to supplementary note (1) or (2), The restriction release conditions include, as a first release condition, that the operation portion is positioned on the second direction side of the first specific position.

[0066] A control method for a work machine according to supplementary note (4) is the control method according to supplementary note (3), The restriction release condition includes, as a second release condition, that the operation unit has performed an operation of changing its posture in the second direction.

[0067] A control method for a work machine according to supplementary note (5) is the control method according to supplementary note (4), The second release condition is set based on the angular velocity and time when the operating portion rotates.

[0068] A control method for a work machine according to supplementary note (6) is the control method according to supplementary note (5), The second release condition is that the time during which the angular velocity of the operation unit is equal to or greater than a threshold value is equal to or greater than a predetermined rate during a predetermined time period.

[0069] A control method for a work machine according to supplementary note (7) is a control method according to any one of supplementary notes (1) to (6), The work machine includes a boom that rotatably supports the operating unit, The stop position, the first specific position, and the second specific position are set corresponding to different rotation positions of the operating part.

[0070] A control method for a work machine according to supplementary note (8) is the control method according to supplementary note (7), the change in the attitude of the actuating unit in the first direction is a rearward rotation, The change in the attitude of the actuation portion in the second direction is a forward rotation.

[0071] The work machine in Appendix (9) is The driving department and a working machine having an actuation unit that changes its posture in a first direction toward the driving unit and in a second direction away from the driving unit; a control unit that automatically stops the operating unit at a preset stop position and performs control to allow a change in attitude of the operating unit from the stop position in the second direction, The control unit After the operating unit automatically stops at the stop position, a restriction control is executed to restrict a change in the attitude of the operating unit in the first direction; the operating unit reaches a first specific position set on the second direction side from the stop position and satisfies a predetermined restriction release condition, thereby stopping the restriction control that is being executed; If the restriction release condition is not satisfied, the restriction control being executed is stopped when the operation unit reaches a second specific position set on the second direction side of the first specific position.

[0072] The control program for a work machine in supplementary note (10) is a program for causing a computer to execute the control method described in any one of supplementary notes (1) to (8).

[0073] The recording medium of supplementary note (11) is a computer-readable recording medium on which the program described in supplementary note (10) is recorded.

[0074] Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these, and the invention can be expanded or modified without departing from the spirit of the invention. [Industrial Applicability]

[0075] The present invention can be used in work machines such as construction machines and agricultural machines. [Explanation of symbols]

[0076] 1 Hydraulic excavator (work machine) 3 Work equipment 31 Boom 32 Arm (operating part) 41 Driving Department 60 Controller (control unit) 312 Second boom (operating part) D1 1st direction D2 2nd direction P0 Stop position P1 1st specific position P2 2nd specific position t time ω angular velocity T0 Predetermined time Ta: The time when the angular velocity is equal to or greater than the threshold. Th threshold

Claims

1. A control method for a work machine having an actuator that changes its posture in a first direction toward a driving unit and in a second direction away from the driving unit, the control method automatically stopping the actuator at a preset stop position and allowing the posture of the actuator to change from the stop position in the second direction, comprising: After the operating unit automatically stops at the stop position, executing a restriction control to restrict a change in the attitude of the operating unit in the first direction; stopping the restriction control that is being executed when the operation unit reaches a first specific position set on the second direction side from the stop position and satisfies a predetermined restriction release condition; and and if the restriction release condition is not satisfied, stopping the restriction control that is being executed when the operating unit reaches a second specific position that is set on the second direction side of the first specific position.

2. 2. The control method for a work machine according to claim 1, further comprising: stopping the restriction control that is being executed if the restriction release condition is satisfied when the operating unit is located between the first specific position and the second specific position.

3. The control method for a work machine according to claim 1 , wherein the restriction release conditions include a first release condition that the operating unit is positioned on a side of the first specific position in the second direction.

4. The control method for a work machine according to claim 3 , wherein the restriction release condition includes, as a second release condition, that the operating unit has performed an operation to change its posture in the second direction.

5. The control method for a work machine according to claim 4, wherein the second release condition is set based on an angular velocity and time when the actuation part rotates.

6. 6. The control method for a work machine according to claim 5, wherein the second release condition is that a time during which the angular velocity of the actuation part is equal to or greater than a threshold value is equal to or greater than a predetermined rate during a predetermined time period.

7. The work machine includes a boom that rotatably supports the operating unit, The control method for a work machine according to claim 1 , wherein the stop position, the first specific position, and the second specific position are set to correspond to different rotation positions of the operating unit.

8. the change in the attitude of the actuating unit in the first direction is a rearward rotation, The method for controlling a work machine according to claim 7 , wherein the change in the attitude of the actuating part in the second direction is a forward rotation.

9. The driving department and a work machine having an actuation unit that changes its posture in a first direction toward the driving unit and in a second direction away from the driving unit; a control unit that automatically stops the operating unit at a preset stop position and performs control to allow a change in attitude of the operating unit from the stop position in the second direction, The control unit After the operating unit automatically stops at the stop position, a restriction control is executed to restrict a change in the attitude of the operating unit in the first direction; the operation unit reaches a first specific position set on the second direction side from the stop position and satisfies a predetermined restriction release condition, thereby stopping the restriction control that is being executed; If the restriction release condition is not satisfied, the restriction control being executed is stopped when the operating unit reaches a second specific position that is set on the second direction side of the first specific position.

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