Work machinery

Abstract

To provide a work machine allowing discomfort on an operator to be reduced as realizing interference prevention while a loading motion and upon stop of the middle of the motion.SOLUTION: A work machine controls motion of a super structure and a front work device such that after the work tool performs only lifting motion, rotation motion of the super structure begins and after the work tool lifts and rotates to reach a passing through height position, the work tool only rotates to reach a position of rotating at the passing through position so as to pass through the passing though position.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Articulated work machines (e.g., hydraulic excavators) having front work mechanisms (e.g., attachments such as a boom, arm, and bucket) driven by a hydraulic actuator are known. This type of work machine performs a transport operation in which excavated earth and sand or other objects are transported to a transport machine (e.g., a dump truck) that is to be loaded, and a discharging operation (e.g., a dumping operation) in which the objects transported by the transport operation are discharged onto the loaded machine, thereby loading the objects onto the loaded machine.

[0003] For example, when a hydraulic excavator (work machine) equipped with a bucket (work implement) is used to load soil onto a dump truck (machine receiving the load), if the bucket is swung and moved while positioned low relative to the dump truck, the bucket may interfere with the dump truck. On the other hand, if the bucket is positioned too high relative to the dump truck when dumping soil, the dump truck may be damaged by the impact of the falling soil. Therefore, when performing loading operations, the hydraulic excavator operator must check the positions of the dump truck and the bucket, pay attention to interference and the soil dumping height, and coordinate the swing operation of the upper rotating body with the operation of the front working mechanism. Therefore, operators performing such operations require skilled operation or assistance from a support device or the like.

[0004] An example of a conventional technique for assisting loading work is described in Patent Document 1. Patent Document 1 discloses a control device for controlling a loading machine including a rotating body that rotates around a rotating center and a work machine that has a bucket attached to the rotating body, the control device including: an avoidance position identifying unit that identifies an interference avoidance position, which is a bucket position that is higher than a loading target and below which the loading target is not present; a timing determining unit that determines a swing start timing based on the remaining swing angle formed by a line extending from the swing center to the work machine and a line extending from the swing center to the interference avoidance position in a plan view from above, and the height of the interference avoidance position; and an operation signal output unit that outputs an operation signal for the work machine when the swing start timing has not yet arrived, and that outputs an operation signal for the work machine when the swing start timing has arrived, causing the rotating body to swing at a swing speed faster than when the swing start timing has not yet arrived. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-132064 Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-described conventional technology, when a loading operation is performed, it is determined that the timing to start swing has arrived when the time it takes for the bucket to reach the height of the interference avoidance position falls short of the required swing time required to swing the remaining swing angle to the interference avoidance position. However, with this type of control, the bucket operates to reach the interference avoidance position simultaneously in both the height direction and the swing direction, regardless of the start position of the loading operation, which raises concerns that the operator may feel uncomfortable due to a discrepancy between the operation performed by the operator and the actual operation.

[0007] The same applies when the loading operation is stopped just before reaching the interference avoidance position. When stopping the loading operation, the time it takes for the swinging motion of the bucket to stop is longer than the time it takes for the movement of the bucket in the vertical direction to stop. For this reason, in the above-mentioned conventional technology, even when the loading operation is stopped midway, it is necessary to continue the movement of the bucket in the vertical direction to prevent interference between the machine being loaded and the bucket. In other words, there is a concern that the operator may feel uncomfortable due to a discrepancy between the operator's operation and the actual movement.

[0008] The present invention has been made in view of the above, and has an object to provide a work machine that can prevent interference and reduce the sense of discomfort felt by the operator during loading operations and when stopping midway through the operation. [Means for solving the problem]

[0009] The present application includes a plurality of means for solving the above-mentioned problems, and one example thereof is a system including a lower traveling body, an upper rotating body rotatably mounted on the lower traveling body, an articulated front working mechanism mounted on the upper rotating body and having a boom, an arm, and a working implement, an attitude detection device that detects the attitude of the upper rotating body and the front working mechanism, a loaded machine position detection device that detects the position of a machine to be loaded that loads and transports an excavation object excavated by the front working mechanism, and a system that controls at least a part of the operation of the upper rotating body and the front working mechanism related to the loading operation of loading the excavation object onto the loaded machine in accordance with information on the excavation position of the excavation object and the position at which the excavation object is discharged onto the loaded machine. In a work machine equipped with a control device, the control device calculates, based on the excavation position, the soil-discharging position, and the position of the loaded machine, a height position, which is a vertical position, and a rotation position, which is a position in the rotation direction, of a passing position through which the working implement must pass in order to reach the soil-discharging position from the excavation position while avoiding contact with the loaded machine during the loading operation, and controls the operation of the upper rotating body and the front working device so that after the working implement has only performed a lifting operation, the rotation operation of the upper rotating body is started, the working implement has risen and rotated until it reaches the height position of the passing position, and then the working implement passes through the passing position by only rotating until it reaches the rotating position of the passing position. [Effects of the Invention]

[0010] According to the present invention, interference can be prevented during loading operations and when the operation is stopped midway, while reducing the sense of discomfort felt by the operator. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a side view schematically showing the appearance of a hydraulic excavator shown as an example of a work machine. [Figure 2] FIG. 2 is a functional block diagram illustrating the hydraulic system and control system of the hydraulic excavator together with the related configuration. [Figure 3]FIG. 2 is a functional block diagram illustrating the processing functions of the control device together with the related configuration. [Figure 4] FIG. 2 is a side view showing the reference coordinate system together with the hydraulic excavator. [Figure 5] FIG. 2 is a top view showing a reference coordinate system together with a hydraulic excavator. [Figure 6] 10 is a flowchart showing processing contents in a carrying operation. [Figure 7] 10 is a flowchart showing processing contents in a carrying operation. [Figure 8] FIG. 10 is a side view showing an example of an operation in which a bucket is moved onto a machine to be loaded by a combination of a swing operation and an operation of a front work implement. [Figure 9] FIG. 10 is a top view showing an example of an operation in which a bucket is moved onto a machine to be loaded by a combination of a swing operation and an operation of a front work implement. [Figure 10] FIG. 10 is a functional block diagram illustrating processing functions of a control device according to a second embodiment together with related configurations. [Figure 11] FIG. 10 is a diagram showing a part of a flowchart illustrating the processing content of a carrying operation according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] In the following, a hydraulic excavator 1 equipped with a bucket 10 as a working implement (attachment) at the tip of a working mechanism (front working mechanism 2) will be exemplified as a working machine, but the present invention may also be applied to other working machines equipped with attachments other than a bucket. Furthermore, the present invention may also be applied to working machines other than hydraulic excavators, so long as they have an articulated working mechanism configured by connecting multiple front members (work implements, booms, arms, etc.) onto a swiveling structure.

[0014] In the following description, when there are multiple identical components, an alphabet may be added to the end of the reference numeral (number), but the alphabet may be omitted to refer to the multiple components collectively. For example, when there are multiple solenoid proportional valves 51a, . . . , 51l, they may be collectively referred to as solenoid proportional valve 51. For simplicity, signal lines and the like whose connection relationships are clear from the description may be omitted from the illustration.

[0015] First Embodiment A first embodiment of the present invention will be described in detail with reference to FIGS.

[0016] FIG. 1 is a side view that schematically shows the appearance of a hydraulic excavator that is shown as an example of a work machine according to this embodiment.

[0017] In Figure 1, a hydraulic excavator 1, which is an example of a work machine, performs excavation work to excavate a surface to be excavated, such as the ground, and loading work to load excavated soil and other objects, such as excavated materials, onto a loading machine 200, such as a transport machine starting with a dump truck (see Figure 8 below). The hydraulic excavator 1 performs the transporting operation and discharging operation described above during this loading work. The hydraulic excavator 1 comprises a multi-joint front working mechanism 2 (working mechanism) that holds an object and rotates up and down or back and forth, and a machine body 3 on which the front working mechanism 2 is mounted.

[0018] The machine body 3 includes a lower traveling body 5 that travels using a right traveling hydraulic motor 4a and a left traveling hydraulic motor 4b provided on the right and left parts of the lower traveling body 5, and an upper rotating body 7 that is attached to the upper part of the lower traveling body 5 via a rotating device and rotates relative to the lower traveling body 5 using a swing hydraulic motor 6 of the swing device. In this embodiment, the right traveling hydraulic motor 4a and the left traveling hydraulic motor 4b may be collectively referred to simply as the traveling hydraulic motor 4 (or the traveling hydraulic motors 4a, 4b).

[0019] The front working implement 2 is an articulated working implement made up of multiple front members attached to the front of the upper rotating structure 7. The upper rotating structure 7 rotates with the front working implement 2 mounted on it. The front working implement 2 comprises a boom 8 connected to the front of the upper rotating structure 7 so as to be rotatable in the vertical direction, an arm 9 connected to the tip of the boom 8 so as to be rotatable in the vertical direction, and a bucket 10 connected to the tip of the arm 9 so as to be rotatable in the vertical direction.

[0020] The boom 8 is connected to the upper rotating body 7 by a boom pin 8a, and rotates by the extension and retraction of a boom cylinder 11. The arm 9 is connected to the tip of the boom 8 by an arm pin 9a, and rotates by the extension and retraction of an arm cylinder 12. The bucket 10 is connected to the tip of the arm 9 by a bucket pin 10a and a bucket link 16, and rotates by the extension and retraction of a bucket cylinder 13.

[0021] A boom angle sensor 14 is attached to the boom pin 8a, which detects the rotation angle of the boom 8 relative to the machine body 3 (i.e., the upper rotating body 7). An arm angle sensor 15 is attached to the arm pin 9a, which detects the rotation angle of the arm 9 relative to the boom 8. A bucket angle sensor 17 is attached to the bucket link 16, which detects the rotation angle of the bucket 10 relative to the arm 9.

[0022] The rotation angles of the boom 8, arm 9, and bucket 10 may be obtained by detecting the angles of the boom 8, arm 9, and bucket 10 with respect to a reference plane such as a horizontal plane using an inertial measurement unit (IMU) and converting them into rotation angles. The rotation angles of the boom 8, arm 9, and bucket 10 may also be obtained by detecting the strokes of the boom cylinder 11, arm cylinder 12, and bucket cylinder 13 using a stroke sensor and converting them into rotation angles.

[0023] An inclination angle sensor 18 is attached to the upper rotating body 7, which detects the inclination angle of the machine body 3 with respect to a reference plane such as a horizontal plane. A rotation angle sensor 19 is attached to the rotation device between the lower running body 5 and the upper rotating body 7, which detects the rotation angle of the upper rotating body 7 with respect to the lower running body 5. An angular velocity sensor 20 is attached to the upper rotating body 7, which detects the rotation angular velocity of the upper rotating body 7.

[0024] Here, the boom angle sensor 14, arm angle sensor 15, bucket angle sensor 17, tilt angle sensor 18, and swing angle sensor 19 constitute an attitude detection device 53 that detects the rotation angles of the front working implement 2 and the swing angle of the upper swing structure 7, etc.

[0025] An operating device for operating the multiple hydraulic actuators 4a, 4b, 6, 11, 12, and 13 is installed in the operator's cab 71 provided on the upper rotating body 7. Specifically, the operating device includes a right travel lever 23a for operating the right travel hydraulic motor 4a, a left travel lever 23b for operating the left travel hydraulic motor 4b, a right operating lever 22a for operating the boom cylinder 11 and the bucket cylinder 13, and a left operating lever 22b for operating the arm cylinder 12 and the swing hydraulic motor 6. In this embodiment, the right travel lever 23a, the left travel lever 23b, the right operating lever 22a, and the left operating lever 22b are collectively referred to as operating levers 22 and 23. The operating levers 22 and 23 are, for example, electric levers. The operating lever 22 is also provided with a switch 24 for issuing a command to execute an automatic transport operation.

[0026] Furthermore, an object detection device 54 is attached to the upper rotating body 7, for example, above the operator's cab 71, for detecting the type and position of an object present around the hydraulic excavator 1, which is a work machine. The object detection device 54 may be, for example, a LiDAR (Light Detection And Ranging) device or a stereo camera. The object detection device 54 detects the machine to be loaded 200 onto which the hydraulic excavator 1 performs loading work, and detects the relative position of the machine to be loaded 200 with respect to the object detection device 54. A plurality of object detection devices 54 may be attached to the hydraulic excavator 1. Furthermore, the position information of the machine to be loaded 200, which is obtained by a server in a management office or the like at the work site, may be acquired via a communication device.

[0027] FIG. 2 is a functional block diagram showing the hydraulic system and control system of the hydraulic excavator together with the related configuration.

[0028] As shown in FIG. 2 , an engine 103, which is a prime mover mounted on the upper rotating structure 7, drives a hydraulic pump 102 and a pilot pump 104. The control device 40 controls the rotational movement of the front working implement 2, the traveling movement of the undercarriage 5, and the swinging movement of the upper rotating structure 7 in accordance with operation information (amount and direction of operation) of the control levers 22, 23 by the operator. Specifically, the control device 40 detects the operation information (amount and direction of operation) of the control levers 22, 23 by the operator using sensors 52a-52f, such as rotary encoders or potentiometers, and outputs control commands corresponding to the detected operation information to the solenoid proportional valves 51a-51l. The solenoid proportional valves 51a-51l are provided on a pilot line 100 and are activated when a control command is input from the control device 40 to output pilot pressure to the flow control valve 101, thereby operating the flow control valve 101. In this embodiment, the operation information of the control levers 22, 23 by the operator is also referred to as the "operation instruction from the operator." In this embodiment, the sensors 52a to 52f that detect this operation information and the sensor 52g that detects the switch 24 for issuing an instruction for the automatic transport operation are collectively referred to as an operation detection device 52.

[0029] The flow control valve 101 controls the pressurized oil supplied from the hydraulic pump 102 to each of the swing hydraulic motor 6, the arm cylinder 12, the boom cylinder 11, the bucket cylinder 13, the right traveling hydraulic motor 4a, and the left traveling hydraulic motor 4b, in accordance with the pilot pressures from the electromagnetic proportional valves 51a to 51l. The electromagnetic proportional valves 51a and 51b output pilot pressures for controlling the pressurized oil supplied to the swing hydraulic motor 6 to the flow control valve 101. The electromagnetic proportional valves 51c and 51d output pilot pressures for controlling the pressurized oil supplied to the arm cylinder 12 to the flow control valve 101. The electromagnetic proportional valves 51e and 51f output pilot pressures for controlling the pressurized oil supplied to the boom cylinder 11 to the flow control valve 101. The electromagnetic proportional valves 51g and 51h output pilot pressures for controlling the pressurized oil supplied to the bucket cylinder 13 to the flow control valve 101. The electromagnetic proportional valves 51i and 51j output pilot pressures for controlling the pressure oil supplied to the right traveling hydraulic motor 4a to the flow control valve 101. The electromagnetic proportional valves 51k and 51l output pilot pressures for controlling the pressure oil supplied to the left traveling hydraulic motor 4b to the flow control valve 101.

[0030] The boom cylinder 11, arm cylinder 12, and bucket cylinder 13 each extend and retract by the supplied pressure oil, rotating the boom 8, arm 9, and bucket 10, respectively. This changes the position and attitude of the bucket 10. The swing hydraulic motor 6 rotates by the supplied pressure oil, rotating the upper swing structure 7. The right traveling hydraulic motor 4a and the left traveling hydraulic motor 4b rotate by the supplied pressure oil, causing the lower traveling structure 5 to travel. In this embodiment, the traveling hydraulic motors 4a and 4b, the swing hydraulic motor 6, the boom cylinder 11, the arm cylinder 12, and the bucket cylinder 13 are collectively referred to as hydraulic actuators 4a, 4b, 6, 11, 12, and 13. In addition, even when the operator does not operate the operation levers 22 and 23, the hydraulic actuators 4a, 4b, 6, 11, 12, and 13 can be driven by operating the electromagnetic proportional valves 51a to 51l and the flow control valve 101 according to commands from the control device 40.

[0031] Fig. 3 is a functional block diagram illustrating the processing functions of the control device together with the related configuration. Fig. 4 is a side view showing the reference coordinate system together with the hydraulic excavator, and Fig. 5 is a top view. Figs. 8 and 9 are diagrams showing an example of an operation for moving the bucket onto the machine to be loaded by combining a swing operation and an operation of the front work implement, with Fig. 8 being a side view and Fig. 9 being a top view.

[0032] Although not shown, the control device 40 is a computer in which a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), an external I / F (Interface), etc. are connected to one another via a bus. An operation detection device 52, an attitude detection device 53, an object detection device 54, and a storage device (not shown, for example, a hard disk drive or a large-capacity flash memory) are connected to the external I / F of the control device 40.

[0033] In FIG. 3, the control device 40 includes an attitude calculation unit 41, a loaded machine position calculation unit 42, a loading target position calculation unit 43, a turning operation prediction unit 44, a work device operation prediction unit 45, an operation judgment unit 46, and an operation command calculation unit 47.

[0034] A reference coordinate system that specifies the positions and postures of the components of the hydraulic excavator 1 is set in advance in the control device 40. As shown in FIGS. 4 and 5 , the reference coordinate system in this embodiment is defined as a right-handed coordinate system with its origin at a point on the axis of the swing center 120 where the undercarriage 5 and the ground G meet. In the reference coordinate system, the forward direction of the undercarriage 5 is defined as the positive direction of the X axis. In this reference coordinate system, the direction in which the swing center 120 extends upward is defined as the positive direction of the Z axis. In this reference coordinate system, the XY plane is defined as being orthogonal to the X axis and the Z axis, and the left side is defined as the positive direction of the Y axis. In the reference coordinate system in this embodiment, the XY plane is fixed to the ground G.

[0035] In addition, in the reference coordinate system of this embodiment, the rotation angle of the upper rotating structure 7 is defined as 0 degrees when the front working implement 2 is parallel to the X-axis. When the rotation angle of the upper rotating structure 7 is 0 degrees, the operating plane of the front working implement 2 is parallel to the XZ plane, the direction of the lifting operation of the boom 8 is the positive direction of the Z-axis, and the dumping direction of the arm 9 and bucket 10 is the positive direction of the X-axis.

[0036] The attitude calculation unit 41 calculates the attitudes and the like of the components of the hydraulic excavator 1 in the reference coordinate system from the detection signal of the attitude detection device 53. Specifically, the attitude calculation unit 41 calculates the rotation angle θbm of the boom 8 with respect to the X-axis from the detection signal of the rotation angle of the boom 8 output from the boom angle sensor 14. The attitude calculation unit 41 calculates the rotation angle θam of the arm 9 with respect to the boom 8 from the detection signal of the rotation angle of the arm 9 output from the arm angle sensor 15. The attitude calculation unit 41 calculates the rotation angle θbk of the bucket 10 with respect to the arm 9 from the detection signal of the rotation angle of the bucket 10 output from the bucket angle sensor 17. The attitude calculation unit 41 calculates the swing angle θsw of the upper swing structure 7 with respect to the X-axis (undercarriage 5) from the detection signal of the swing angle of the upper swing structure 7 output from the swing angle sensor 19.

[0037] Furthermore, the posture calculation unit 41 calculates the planar positions and heights of the boom 8, arm 9, and bucket 10 based on the calculated rotation angles θbm, θam, θbk of the front working implement 2 and the swing angle θsw of the upper swing structure 7, as well as the dimension Lbm of the boom 8, the dimension La of the arm 9, and the dimension Lbk of the bucket 10. Note that the dimension Lbm of the boom 8 is the length from the boom pin 8a to the arm pin 9a. The dimension Lam of the arm 9 is the length from the arm pin 9a to the bucket pin 10a. The dimension Lbk of the bucket 10 is the length from the bucket pin 10a to the tip of the bucket 10 (for example, the tip of the tooth). Furthermore, when the swing angle is set to zero, the boom pin 8a is offset from the center of swing by Lox in the X-axis direction and Loy in the Y-axis direction.

[0038] Furthermore, the attitude calculation unit 41 calculates the inclination angle θg of the machine body 3 (undercarriage 5) with respect to a reference plane DP from the detection signal of the inclination angle of the machine body 3 output from the inclination angle sensor 18. The reference plane DP is, for example, a horizontal plane perpendicular to the direction of gravity. The inclination angle θg includes a pitch angle, which is a rotation angle about the Y axis, and a roll angle, which is a rotation angle about the X axis. The attitude calculation unit 41 calculates a ground angle γ, which is the angle of the bucket 10 with respect to the ground G, from the rotation angles θbm, θam, and θbk of the front working implement 2. The ground angle γ of the bucket 10 is the angle formed by a line passing through the tip of the bucket 10 and the bucket pin 10a with respect to the ground G.

[0039] The loaded machine position calculation unit 42 calculates the position of the loaded machine 200 in the reference coordinate system from the position of the loaded machine 200 detected by the object detection device 54. The object detection device 54 is attached to the upper rotating body 7. Therefore, the loaded machine position calculation unit 42 can calculate the planar position and height of the loaded machine 200 in the reference coordinate system based on the rotation angle θsw of the upper rotating body 7 and the attachment position of the object detection device 54 relative to the reference coordinate system.

[0040] The loading target position calculation unit 43 specifies the planar position and height of the earth-releasing position P6 (i.e., the loading position where earth and sand are loaded onto the loaded machine 200) where earth and sand will be released onto the loaded machine 200, based on the calculation result of the loaded machine position calculation unit 42. For example, the planar position of P6 may be the center of the loaded machine 200 when viewed from above. The height of P6 may be the height Hv (see FIG. 8) of the loaded machine 200 plus a margin Hm. The margin Hm may be, for example, the sum of the dimension Lbk of the bucket 10. Alternatively, it may be the sum of the dimension Lbkbc to the bottom of the bucket.

[0041] The loading target position calculation unit 43 calculates the control target swing angle θswtgt for the tip of the arm 9 to reach the release position P6. In a plan view, this can be determined from the angle formed by the straight line extending from the boom pin 8a to the tip of the arm 9 and the X-axis of the vehicle body reference coordinate system.

[0042] The loading target position calculation unit 43 calculates the target angle θbmtgt of the boom 8 and the target angle θamtgt of the arm 9 for the tip of the arm 9 to reach the release position P6. The target angle θbmtgt of the boom 8 and the target angle θamtgt of the arm 9 can be calculated from the distance in a plan view from the boom pin 8a to the release position P6 and the height from the boom pin 8a to the release position P6.

[0043] The loading target position calculation unit 43 calculates the passing position P5. For example, the height of the passing position P5 is equal to the height of the dumping position P6. The planar position of the passing position P5 corresponds to the position of the tip of the arm 9 when the arm 9 is rotated in the direction of the hydraulic excavator 1 at the start of automatic transport control by a predetermined margin from the control target swing angle for reaching the dumping position P6. In other words, the passing position P5 is the position through which the tip of the arm 9 passes when the boom 8 and arm 9 are at the target angle and the swing angle is rotated in the control start direction by a predetermined margin from the control target swing angle. This predetermined margin may be determined, for example, so that the vessel and the bucket 10 do not come into contact in a plan view. The swing angle when the tip of the arm 9 is located at the passing position P5 is defined as the passing position swing angle.

[0044] In other words, the passing position P5 is, for example, a virtual point that determines the height position and rotation position through which the arm 6 must pass in order for the arm 9 to reach the dumping position P6 from the excavation position P1 while avoiding contact with the loaded machine 200. The passing position P5 can be calculated, for example, based on the excavation position P1 and the dumping position P6 (for example, the relative positional relationship between the excavation position P1 and the dumping position P6), and the position of the loaded machine 200. The passing position P5 can be calculated taking into consideration, for example, the position of the front working implement 2 at the excavation position P1 (for example, the position of the tip of the arm 9 in this embodiment), the attitude of the front working implement 2 at the excavation position P1 and the dumping position P6, the external shape of the loaded machine 200, the shapes of the objects already loaded on the loaded machine 200 and the objects to be excavated, etc.

[0045] The swing operation prediction unit 44 predicts the swing operation when the hydraulic excavator 1 automatically performs a swing operation, based on outputs from the operation detection device 52, the attitude calculation unit 41, and the loading target position calculation unit 43. It predicts the time history of the operation from the swing angle when the operator issues a transport command (control start swing angle) to the swing angle (passing position swing angle) that will be reached if the excavator is to stop at the passing position P5. The time history that predicts the time T_swds when the swing deceleration starts includes a prediction of the operation of starting the swing operation and accelerating the swing, and a prediction of the operation of deceleration to stop at the passing position swing angle.

[0046] The accelerating turning operation can be predicted, for example, by the following (Equation 1) which expresses the relationship of the predicted turning angular velocity ωswpre with respect to the flow rate q in a second-order lag system.

[0047]

number

[0048] Here, in the above (Equation 1), s represents the Laplace operator, Ks represents the gain, ωnsw represents the natural angular frequency, and ζnsw represents the damping ratio.

[0049] The predicted turning angle θswpre is obtained by integrating the angular velocity calculated by Equation 1. Note that the prediction may use a more detailed hydraulic model or may use actually measured turning angular velocity data, and the prediction method is not limited.

[0050] The deceleration operation for decelerating the swirl operation and stopping it at the control end swirl angle, that is, the swirl flow angle θswd from when the swirl operation starts to decelerate until it stops, can be calculated by the following (Equation 2).

[0051]

number

[0052] Here, in the above (Equation 2), ωsw is the swing angular velocity, and Dlim is the deceleration that can occur when the hydraulic excavator 1 decelerates during swing deceleration.

[0053] From the above (Equation 2), the turning operation starts to decelerate when the sum of the turning flow angle θswd and the turning angle θsw becomes equal to the passing position turning angle, so that the time history until the turning operation starts to decelerate and the time when deceleration starts after the turning operation starts can be predicted. Note that the predicted time from the start of the turning operation until the turning operation starts to decelerate is T_swds.

[0054] The work implement operation prediction unit 45 predicts the operation of the front work implement 2 when the hydraulic excavator 1 automatically performs a transport operation, based on outputs from the operation detection device 52, the attitude calculation unit 41, and the loading target position calculation unit 43. The operation of the front work implement 2 is predicted from the time when the swing operation is started. The predicted time history includes the operation of the front work implement 2, which is already operating, to decelerate due to the swing operation, and the prediction of the deceleration operation to stop the boom 8 and arm 9 at the target angle to reach the soil-discharging position P6. This is because, in the control flow described below, since the front work implement 2 starts operating before the swing operation, the amount of hydraulic oil supplied to drive the front work implement 2 is reduced due to the swing operation, and the amount of deceleration of the operation of the front work implement 2 is taken into consideration.

[0055] The amount of deceleration of the front working implement 2 due to a turning operation can be predicted, for example, using the following (Equation 3), which expresses the relationship between the flow rate q and the cylinder speed Vcyl in a second-order lag system.

[0056]

number

[0057] Here, in the above (Equation 3), s represents the Laplace operator, Kf represents the gain, ωnf represents the natural angular frequency, and ζnf represents the damping ratio.

[0058] For the prediction, a more detailed hydraulic model may be used, or the relationship between the cylinder speed Vcyl when the front working implement 2 is operated independently and when the front working implement 2 is operated in combination with a swing operation may be stored in advance and used to predict the amount of deceleration due to a swing operation.

[0059] The deceleration operation for slowing down the movement of the boom 8 and arm 9 and stopping them at the target angle of the boom 8 and arm 9 can also be predicted in the same way as the deceleration of the swing operation. In other words, the operation leading up to the stop can be predicted by starting deceleration when the sum of the change in angle until the boom 8 and arm 9 stop when decelerated at a certain deceleration and the predicted angle at a certain point in time becomes equal to the target angle. In other words, the time history and time of the front movement until the tip of the arm 9 reaches the release position P6 or the passing position P5 can be predicted. The predicted time from the start of the swing operation until the front movement stops is defined as T_fr.

[0060] Of the angle of the boom 8 and the angle of the arm 9 that must be changed from the posture at the end of excavation to the release position P6, the angle of the boom 8 is often larger. Therefore, the work implement operation prediction unit 45 may be configured to only predict the operation of the boom 8. Also, with regard to the release position P6 and the passing position P5, if it is determined that the release position P6 and the passing position P5 can be reached above the loaded machine 200 by only the operation and rotation of the boom 8 while keeping the angle of the arm 9 at the end of excavation, the release position P6 does not need to be limited to the center of the loaded machine 200. In that case, the work implement operation prediction unit 45 only needs to predict the operation of the boom 8.

[0061] The movement determination unit 46 determines whether or not to perform a swing operation based on outputs from the operation detection device 52, the swing operation prediction unit 44, and the work implement movement prediction unit 45. That is, the movement determination unit 46 determines whether or not to perform a swing operation based on the predicted time T_swds from the start of swing until the swing starts to decelerate, predicted by the swing operation prediction unit 44, and the predicted time T_fr from the start of swing until the work implement stops, predicted by the work implement movement prediction unit 45.

[0062] The operation determination unit 46 determines to start the rotation operation when T_swds is equal to T_fr or when T_swds is greater than T_fr, that is, when the tip of the arm 9 reaches the height and reach required to reach P6, or when it is predicted that the tip will stop at the passing position rotation angle if the rotation operation starts to decelerate.

[0063] The operation command calculation unit 47 outputs a command to the electromagnetic proportional valve 51 based on the determination result of the operation determination unit 46. Specifically, when the operator instructs the hydraulic excavator 1 to transport the earth and sand excavated by the hydraulic excavator 1 to the loaded machine 200, the operation command calculation unit 47 commands the electromagnetic proportional valve 51 to operate the hydraulic actuator of the front working implement 2. Furthermore, when the operation determination unit 46 determines that a swing operation should be started, the operation command calculation unit 47 commands the electromagnetic proportional valve 51 to perform a swing operation. The operator of the hydraulic excavator 1 gives a command to transport the earth and sand excavated by the hydraulic excavator 1 and held in the bucket 10 to the loaded machine 200 by operating the switch 24 on the operation lever 22.

[0064] 6 and 7 are flowcharts showing the processing contents in the carrying operation.

[0065] 6 and 7, when the operation detection device 52 detects an instruction for automatic transport operation by the operator operating the switch 24, the loaded machine position calculation unit 42 of the control device 40 first calculates the position of the loaded machine 200 based on information from the object detection device 54 (step S101).

[0066] Subsequently, the loading target position calculation unit 43 calculates the earth release position P6 (step S102).

[0067] Subsequently, the loading target position calculation unit 43 calculates the target angle θbmtgt of the boom 8 and the target angle θamtgt of the arm 9 required for the tip of the arm 9 to reach the release position P6 (step S103).

[0068] Subsequently, the loading target position calculation unit 43 calculates the target swing angle θswtgt, which is the swing angle required for the tip of the arm 9 to reach the release position P6 (step S104).

[0069] Subsequently, the loading target position calculation unit 43 calculates the passing position P5 and the passing position turning angle (step S105).

[0070] Subsequently, the attitude calculation unit 41 calculates the angle, angular velocity, and rotation angle and angular velocity of the boom 8 and arm 9 based on the information from the attitude detection device 53 (step S106).

[0071] Next, it is determined whether the angles of the boom 8 and the arm 9 have reached the target angles (step S107).

[0072] If the determination result in step S107 is NO, that is, if it is determined that the target angle has not been reached, the operation command calculation unit 47 then issues an instruction to the electromagnetic proportional valve 51 so that the angles of the boom 8 and arm 9 reach the target angle (step S108).

[0073] If the determination result in step S107 is YES, or if the processing of step S108 is completed, i.e., if the target angle is reached, it is then determined whether or not a turning operation has started (step S109). Note that the determination of whether or not a turning operation has started may be made using the calculation result of the turning angular velocity by the attitude calculation unit 41, or may be made by storing whether or not a turning operation command has been issued.

[0074] If the determination result in step S109 is NO, that is, if it is determined that the rotation operation has not started, the rotation operation prediction unit 44 then predicts the time history of the rotation operation until the tip of the arm 9 reaches the passing position P5 (step S110). This prediction of the rotation operation includes at least the period from the start of the rotation operation to the start of deceleration of the rotation operation. The time from the start of the rotation operation until the rotation operation starts to decelerate is stored as T_swds.

[0075] Next, the work implement operation prediction unit 45 uses the time when rotation starts as an initial value and predicts the time history of the operation of the boom 8 and arm 9 until the tip of the arm 9 reaches the release position P6 or the passing position P5, in other words, the time history until the boom 8 and arm 9 reach the target angle (step S111). The angle and angular velocity of the boom 8 and arm 9 acquired in step S106 can be used as the initial values for this prediction of the work implement operation. The time predicted to reach the target angle is stored as T_fr.

[0076] Next, the operation determination unit 46 compares T_swds with T_fr and determines whether T_swds is equal to or greater than T_fr, that is, whether it is predicted that the boom 8 and arm 9 will reach the target angle and that the rotation operation will start to decelerate at the same time or thereafter, causing the rotation to stop at the passing position P5 (step S112).

[0077] If the determination result in step S112 is NO, that is, if T_swds is not equal to or greater than T_fr, the processes of steps S106 to S111 are repeated until the determination result becomes YES. Note that in step S111, if either the boom 8 or the arm 9 reaches the target angle during the repeated processes of steps S106 to S111, which occurs when the determination result in step S112 is NO, it is only necessary to predict the movement of the one that has not yet reached the target angle.

[0078] If the determination result in step S112 is YES, that is, if T_swds is equal to or greater than T_fr, then the motion command calculation unit 47 issues a command for a turning motion (step S113).

[0079] Next, if the determination result in step S109 is YES, or if the processing in step S113 is completed, i.e., if a turning operation has started, it is then determined whether or not the target turning angle will be reached when the turning operation starts to decelerate (step S114).

[0080] If the determination result in step S114 is YES, that is, if it is determined that the target turning angle will be reached, then a turning stop command is output (step S115).

[0081] Also, if the determination result in step S114 is NO, or if the processing in step S115 is completed, it is then determined whether the rotation angle, the angle of the boom 8, and the angle of the arm 9 have reached the target angles (step S116).

[0082] If the determination result in step S116 is NO, that is, if it is determined that the target angle has not been reached, the process returns to step S105.

[0083] If the determination result in step S116 is YES, the automatic transport operation process ends.

[0084] The operation of the present embodiment configured as above will now be described.

[0085] As shown in Figures 8 and 9, the state of the bucket 10 at the end of excavation at excavation position P1 is set to state S1. At this point, the operator commands automatic transport operation. Between state S1 and state S2, only the boom 8 and arm 9 move. This processing state corresponds to the case in the flowchart of Figure 6 where it is determined in step S112 that T_swds will not be equal to or greater than T_fr, and the processing of steps S106 to S111 is repeated. Therefore, the state S1 moves to state S2 only by the movement of the boom 8 and arm 9.

[0086] In state S2, if it is determined in step S112 of the flowchart in Figure 6 that T_swds is greater than or equal to T_fr, a swing operation is initiated (see step S113 in Figure 6), the boom 8 and arm 9 move simultaneously with the swing operation, and the bucket 10 moves from state S2 to state S3.

[0087] State S3 is a state in which the movements of both the boom 8 and the arm 9 have been completed. This processing state corresponds to the case in which it is determined in step S107 of the flowchart in Figure 6 that the angles of the boom 8 and the arm 9 have reached the target angles. In state S3, the deceleration of the rotation movement has not yet started.

[0088] State S4 is the time when the turning operation starts to decelerate. The processing state at this time corresponds to the case where it is determined that the turning operation will reach the target turning angle when it starts to decelerate, and a turning stop command is output in step S114 of the flowchart in Fig. 7 (see step S115 in Fig. 7).

[0089] State S5 is a situation in which the tip of arm 9 passes through passing position P5, which is a position with a margin of a predetermined rotation angle from the target rotation angle for reaching release position P6 while the rotation operation is decelerating.

[0090] Finally, the turning operation stops, and the state reaches state S6, where the turning operation stops and the tip of the arm 9 stops at the soil release position P6.

[0091] The effects of the present embodiment configured as above will be described.

[0092] In the prior art, compared to the operation of the front working implement 2, such as the boom 8 or arm 9, it takes time for the swinging operation to stop even after receiving a stop command. Therefore, in an automatic transport operation in which the lifting operation of the front working implement 2 is completed near the machine to be loaded 200, even if a command to stop the operation is given during the automatic transport operation, it is necessary to continue operating the front working implement 2 to avoid interference with the machine to be loaded 200. However, with such an operation, there is a possibility that the operation by the operator and the actual operation may differ significantly, raising concerns that the operator may feel uncomfortable. For this reason, in the prior art, even when the loading operation is stopped midway, it is necessary to continue the movement of the bucket in the height direction to prevent interference between the machine to be loaded and the bucket. In other words, there is a concern that the operator may feel uncomfortable due to the difference between the operation by the operator and the actual operation.

[0093] In contrast to this, in this embodiment, the operation of the upper rotating body and the front working implement is controlled based on the predicted results of the swinging operation and the operation of the front working implement so that the working implement only performs a lifting operation, then the swinging operation of the upper rotating body is initiated, the working implement rises and swings until it reaches the height of the passing position, and then the working implement only swings until it reaches the swing position of the passing position and passes through the passing position.This makes it possible to prevent interference during loading operations and when stopped midway through the loading operation, while reducing the sense of discomfort felt by the operator.

[0094] That is, in this embodiment, if an instruction to stop the automatic transport operation is given during a transition from state S1 to state S2, the swing operation has not yet started, so there is no risk of interference with the loaded machine 200 even if the operation of the boom 8 or arm 9 is immediately stopped. Also, if an instruction to stop the automatic transport operation is given during a transition from state S2 to state S3, if the swing is stopped from that position, it is possible to stop at passing position P5 before the loaded machine 200 or at a swing angle before reaching passing position P5, so there is no risk of interference with the loaded machine 200 even if the operation of the boom 8 or arm 9 is immediately stopped. Furthermore, if an instruction to stop the automatic transport operation is given after state S3, the bucket 10 has already risen to a height where it will not interfere with the loaded machine 200, so there is no risk of interference.

[0095] Furthermore, according to this embodiment, in a transport operation that combines a swing operation and the operation of the front working implement 2, the operation of the front working implement 2 is carried out first, so the operator can issue a command for the automatic transport operation without worrying about interference with the machine 200 to be loaded.

[0096] The deceleration of the swing when stopping at the passing position P5 predicted by the swing operation prediction unit 44 and the deceleration of the swing used for determining the deceleration for stopping the swing operation at the target swing angle in step S114 of the flowchart in Fig. 7 may be equal, or may be different values so that the deceleration when stopping at the passing position P5 is a larger deceleration. For example, the deceleration when stopping at the passing position P5 may be the maximum deceleration that the hydraulic excavator 1 can generate, and the deceleration when stopping at the target swing angle may be a smaller deceleration than the maximum deceleration. In this case, by relatively reducing the deceleration when decelerating the actual swing operation, it is possible to reduce the sense of discomfort felt by the operator.

[0097] Furthermore, in this embodiment, an example has been described in which the angles of the boom 8 and the arm 9 are controlled, but this is not limiting. For example, the bucket 10 may be controlled so that the ground angle thereof when the automatic transport control is instructed by the operator is maintained while the automatic transport control is being executed, or the bucket 10 may be controlled so that an instruction to operate the bucket 10 from the operator is accepted.

[0098] <Second embodiment> A second embodiment of the present invention will be described with reference to Figures 10 and 11. In the figures, the same members as those in the other embodiments are given the same reference numerals, and the description thereof will be omitted.

[0099] Fig. 10 is a functional block diagram showing the processing functions of the control device together with the related configuration, and Fig. 11 is a diagram showing a part of a flowchart showing the processing contents in the carrying operation.

[0100] 10, the hydraulic excavator 1 is equipped with a transported object information acquisition device 55. The transported object information acquisition device 55 calculates the mass of the transported object (e.g., excavated earth and sand) stored in the bucket 10. The control device 40 uses the information obtained by the transported object information acquisition device 55 in the swing operation prediction unit 44 and the work implement operation prediction unit 45 to make predictions.

[0101] The flowchart shown in Fig. 11 differs from the flowchart shown in Fig. 7 in that a process (step S200) for acquiring information about the transported object in the bucket 10 is added before the process of S106. By using the information about the transported object in the bucket 10 as in step S200, the swing operation prediction unit 44 and the work implement operation prediction unit 45 of the control device 40 can make operation predictions with higher accuracy.

[0102] The other configurations are the same as those in the first embodiment.

[0103] The present embodiment configured as above can also achieve the same effects as the first embodiment.

[0104] Furthermore, the control device 40 can make more accurate operation predictions.

[0105] <Additional Notes> The present invention is not limited to the above-described embodiments, and includes various modifications and combinations within the scope of the gist thereof. Furthermore, the present invention is not limited to those including all of the configurations described in the above-described embodiments, and includes those in which some of the configurations are omitted. Furthermore, the above-described configurations, functions, etc. may be realized in part or in whole by designing them as, for example, integrated circuits. Furthermore, the above-described configurations, functions, etc. may be realized in software by a processor interpreting and executing a program that realizes each function. [Explanation of symbols]

[0106] 1...hydraulic excavator, 2...front working device, 3...machine body, 4...travel hydraulic motor, 5...lower traveling body, 6...swing hydraulic motor, 7...upper rotating body, 8...boom, 8a...boom pin, 9...arm, 9a...arm pin, 10...bucket, 10a...bucket pin, 11...boom cylinder, 12...arm cylinder, 13...bucket cylinder, 14...boom angle sensor, 15...arm angle sensor, 16...bucket link, 17...bucket angle sensor, 18...tilt angle sensor, 19...swing angle sensor, 20...angular velocity sensor, 22, 23...operating lever, 24...switch, 40...control device, 41...attitude calculation unit, 42...loaded machine position calculation unit, 43...loading target position calculation unit, 44...swing operation prediction unit, 45...work device operation prediction unit, 46...operation determination unit, 47...operation command calculation unit, 51...electromagnetic proportional valve, 52...operation detection device, 53...attitude detection device, 54...object detection device, 55...transported object information acquisition device, 71...operator's cab, 100...pilot line, 101...flow control valve, 102...hydraulic pump, 103...engine, 104...pilot pump, 120...swing center, 200...loaded machine (dump truck)

Claims

1. a lower running body; an upper rotating body rotatably attached on the lower traveling body; an articulated front working device attached to the upper rotating body and including a boom, an arm, and a working tool; a posture detection device that detects the postures of the upper rotating body and the front working implement; a loaded machine position detection device that detects the position of a loaded machine that loads and transports the excavation object excavated by the front working device; a control device that controls at least a part of the operation of the upper rotating body and the front working device related to a loading operation of loading the excavation object onto the machine to be loaded, in accordance with information on an excavation position of the excavation object and a position where the excavation object is to be released onto the machine to be loaded, The control device based on the excavation position, the soil-discharging position, and the position of the loaded machine, calculate a height position, which is a vertical position, and a turning position, which is a turning position, of a passing position through which the working tool passes in order to reach the soil-discharging position from the excavation position while avoiding contact with the loaded machine during the loading operation; a work machine, characterized in that the operation of the upper rotating body and the front working device is controlled so that the working implement only performs a lifting operation, then a swinging operation of the upper rotating body is initiated, the working implement rises and swings until it reaches the height position of the passing position, and then the working implement passes through the passing position while only swinging until it reaches the swing position of the passing position.

2. 2. The work machine according to claim 1, The control device predicting a required time from when the working tool starts to rise until it reaches the height position of the passing position when the working tool performs a rising operation at the fastest speed, and a required time from when the upper rotating body starts to decelerate until it stops when the upper rotating body rotates at the fastest speed; a control unit configured to control the lifting operation of the work implement and the rotation operation of the upper rotating body to stop at a rotation position that does not reach the rotation position of the passing position when the lifting operation of the work implement and the rotation operation of the upper rotating body begin to stop upon receiving a signal to interrupt automatic control of the upper rotating body and the front working device in accordance with the required time.

3. 2. The work machine according to claim 1, The control device uses a deceleration of the upper rotating body used to predict the time required from when the upper rotating body starts to decelerate until it stops, the deceleration being greater than the deceleration of the upper rotating body when it starts to decelerate and stops at the soil release position.

4. 2. The work machine according to claim 1, The control device uses information on an object carried by the implement to predict the operation of the upper rotating body and the front working implement.

Images