Work machine

Abstract

Provided is a work machine capable of quickly performing excavation along a target excavation surface while causing a work tool having a three-axis rotation degree of freedom to directly face the target excavation surface.　A control device comprises: a work point coordinate calculation unit for calculating the coordinates of a plurality of work points set on the work tool; a target point coordinate calculation unit for calculating the coordinates of a plurality of target points respectively corresponding to the plurality of work points; a work point deviation calculation unit for obtaining each deviation between the coordinates of the plurality of work points and the coordinates of the plurality of target points; a work point speed vector calculation unit for calculating each speed vector of the plurality of work points such that the total of the deviations is reduced; and an actuator target speed calculation unit for calculating each target speed of a plurality of actuators on the basis of each speed vector.

Description

Work machinery

[0001] The present invention relates to a work machine such as a hydraulic excavator.

[0002] BACKGROUND ART Conventionally, there has been a technology for controlling a tiltrotator bucket that enables the bucket angle to be kept parallel to slopes of any shape in order to improve the efficiency of construction work such as slope excavation.

[0003] For example, Patent Document 1 discloses a system for controlling a work machine that includes a support part that is operably supported on a vehicle body, a tiltrotator attached to the tip of the support part, and an attachment that has a cutting edge and is supported via the tiltrotator so that it can rotate about three axes that intersect with each other on different planes relative to the support part, the system including a processor that acquires measurement values ​​from a plurality of sensors, calculates the attitude of the attachment with respect to the vehicle body based on the measurement values, determines a virtual rotation axis based on the calculated attitude of the attachment, generates a control signal for the tiltrotator that rotates the attachment about the virtual rotation axis so that a design surface (target excavation surface) and the cutting edge of the attachment approach parallelism, and outputs the generated control signal.

[0004] JP 2023-51363 A

[0005] The system described in Patent Document 1 makes it easy to orient an attachment (work tool) directly toward a target excavation surface. However, when excavating with a work machine incorporating this system, after orienting the attachment directly toward the target excavation surface, an additional operation must be performed to excavate the attachment along the target excavation surface, leaving room for improvement in terms of work efficiency.

[0006] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a work machine that can quickly perform excavation along a target excavation surface while facing a work tool with three rotational degrees of freedom directly against the target excavation surface.

[0007] In order to achieve the above object, the present invention provides a work machine comprising: a lower traveling body; an upper rotating body rotatably attached to the lower traveling body; an articulated work machine equipped with a work implement attached to the upper rotating body so as to be rotatable in the vertical direction and having three degrees of freedom of rotation at its tip; a plurality of actuators for driving the articulated work machine; an actuator speed sensor for detecting the speeds of each of the plurality of actuators; an attitude sensor for detecting the attitude of the upper rotating body and the articulated work machine; and a control device for controlling the plurality of actuators, wherein the control device comprises a work point coordinate calculation unit for calculating the coordinates of a plurality of work points set on the work implement based on detection values ​​of the attitude sensor; and a target point calculation unit for calculating the coordinates of a plurality of target points respectively corresponding to the plurality of work points. The apparatus comprises a reference point coordinate calculation unit, a working point deviation calculation unit that calculates the absolute value of each deviation between the coordinates of the plurality of working points calculated by the working point coordinate calculation unit and the coordinates of the plurality of target points calculated by the target point coordinate calculation unit, a working point velocity vector calculation unit that calculates each velocity vector of the plurality of working points so that the sum of the absolute values ​​of each deviation calculated by the working point deviation calculation unit is small, an actuator target velocity calculation unit that calculates each target velocity of the plurality of actuators based on each velocity vector of the plurality of working points calculated by the working point velocity vector calculation unit, and an actuator control unit that controls the plurality of actuators so that each target velocity calculated by the actuator target velocity calculation unit matches each velocity detected by the actuator velocity sensor.

[0008] According to the present invention, the operation of facing a work tool having three degrees of rotational freedom toward the target excavation surface and the operation of bringing the work tool to the target excavation surface are performed simultaneously in parallel, making it possible to quickly excavate along the target excavation surface while facing the work tool toward the target excavation surface.

[0009] FIG. 1 is a perspective view schematically showing the appearance of a hydraulic excavator, which is an example of a work machine according to a first embodiment. FIG. 2 is a schematic diagram of a tiltrotator bucket according to the first embodiment. FIG. 3 is a functional block diagram schematically showing a portion of the processing functions of a control device for the hydraulic excavator according to the first embodiment. FIG. 4 is a diagram showing a method for orienting the tiltrotator bucket according to the first embodiment with a target excavation surface in the x-z plane. FIG. 5 is a diagram showing a method for orienting the tiltrotator bucket according to the first embodiment with a target excavation surface in the x-y plane. FIG. 6 is a diagram showing a method for orienting the tiltrotator bucket according to the first embodiment with a target excavation surface in the y-z plane. FIG. 7 is a flowchart showing the processing contents of the control device according to the first embodiment. FIG. 8 is a functional block diagram schematically showing a portion of the processing functions of a control device for a hydraulic excavator according to a second embodiment. FIG. 9 is a schematic diagram showing a method for setting a target point according to the second embodiment. FIG. 10 is a flowchart showing the processing contents of the control device according to the second embodiment. FIG. 11 is a functional block diagram schematically showing a portion of the processing functions of a control device for a hydraulic excavator according to a third embodiment. FIG. 12 is a flowchart showing the processing contents of the control device according to the third embodiment.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a hydraulic excavator equipped with a front working implement (working device) will be described as an example of a work machine, but the present invention can also be applied to other machines equipped with mechanisms that include multiple rotational movements, such as industrial or medical robot arms.

[0011] A first embodiment of the present invention will be described with reference to FIGS.

[0012] Fig. 1 is a perspective view showing a typical appearance of a hydraulic excavator, which is an example of a work machine according to this embodiment, Fig. 2 is a typical view of a tiltrotator bucket according to this embodiment, and Fig. 3 is a functional block diagram showing a typical portion of the processing functions of a control device for the hydraulic excavator according to this embodiment.

[0013] 1 and 2 , the hydraulic excavator 100 includes a front working machine (articulated working machine) 24 configured by connecting a plurality of driven members (a boom 8, an arm 9, and a bucket (working implement) 10) that each rotate in a vertical direction, and an upper rotating body 22 and a lower traveling body 20 that form a vehicle body, and the upper rotating body 22 is provided so as to be able to rotate relative to the lower traveling body 20 via a swing mechanism 21. The swing mechanism 21 includes a swing motor 23 and an attitude sensor 26D, and the swing motor 23 drives the upper rotating body 22 to swing relative to the lower traveling body 20, and the attitude sensor 26D detects the swing angle relative to the lower traveling body 20.

[0014] The base end of a boom 8 of the front working implement 24 is supported on the front part of the upper rotating body 22 so as to be rotatable in the vertical direction, one end of an arm 9 is supported on an end (tip) different from the base end of the boom 8 so as to be rotatable in the vertical direction, and a bucket (work implement) 10 is supported on the other end of the arm 9 so as to be rotatable in the vertical direction. The boom 8, arm 9, bucket 10, upper rotating body 22, and lower traveling body 20 are driven by hydraulic actuators, namely, a boom cylinder 5, an arm cylinder 6, a bucket cylinder 7, a swing motor 23, and left and right traveling motors 3 (only one traveling motor is shown), respectively.

[0015] Here, a vehicle body coordinate system is set up with the intersection of the rotation center axis 25 of the upper rotating body 22 and the underside of the upper rotating body 22 as the origin, the z-axis being positive upward along the rotation center axis 25, the x-axis being positive forward in the fore-and-aft direction from the origin perpendicular to the z-axis, and the y-axis being positive rightward in the left-right direction from the origin perpendicular to the z-axis and x-axis.

[0016] A cab 2 on which an operator sits is mounted on the front left side of the upper rotating body 22. A control device 28 that controls the overall operation of the hydraulic excavator 100 is also disposed on the upper rotating body 22. The cab 2 is provided with operation levers (operation devices) 2a, 2b that output operation signals for operating the hydraulic actuators 5 to 7, 23. Although not shown, the operation levers 2a, 2b can each be tilted forward, backward, left, and right, and include a detection device (not shown) that electrically detects the amount of tilt of the lever, which is the operation signal, i.e., the lever operation amount, and outputs the lever operation amount detected by the detection device to the control device 28 (described below) via electrical wiring. In other words, the operation of the hydraulic actuators 5 to 7, 23 is assigned to the forward, backward, left, and right directions of the operation levers 2a, 2b, respectively.

[0017] The operation of the boom cylinder 5, arm cylinder 6, bucket cylinder 7, swing motor 23, and left and right travel motors 3 is controlled by using a control valve or the like to control the direction and flow rate of hydraulic oil supplied to each of the hydraulic actuators 3, 5 to 7, 23 from a hydraulic pump device driven by a prime mover such as an engine or electric motor (not shown). The operation of the control valve is controlled by a control device 28 based on operation signals from the operation levers 2a and 2b, thereby controlling the operation of each of the hydraulic actuators 5 to 7, 23.

[0018] Attitude sensors 26A, 26B, and 26C are attached to the base of the boom 8, the connection between the boom 8 and the arm 9, and the connection between the arm 9 and the bucket 10, respectively. Attitude sensor 26D is attached to the upper rotating body 22. As shown in FIG. 3 , attitude sensor 26A measures the angle between the longitudinal direction of the boom 8 (a line connecting the rotation centers at both ends) and the x-y plane and transmits the angle to the control device 28. Attitude sensor 26B measures the angle between the longitudinal direction of the boom 8 (a line connecting the rotation centers at both ends) and the longitudinal direction of the arm 9 (a line connecting the rotation centers at both ends) and transmits the angle to the control device 28. Attitude sensor 26C measures the angle between the longitudinal direction of the arm 9 (a line connecting the rotation centers at both ends) and the longitudinal direction of the bucket 10 (a line connecting the rotation center and the toe) and transmits the angle to the control device 28. Attitude sensor 26D measures the tilt angle of the upper rotating body 22 and transmits the angle to the control device 28.

[0019] In this embodiment, the swing center 27 of the front working implement 24 (the connection point with the upper rotating body 22 of the boom 8) is described as being located at a position different from the central axis of rotation 25, but the swing center 27 may also be located so that the central axis of rotation 25 and the swing center 27 intersect.

[0020] Furthermore, as shown in FIG. 2 , the hydraulic excavator 100 according to this embodiment is provided with a tiltrotator bucket (work implement) 46, instead of the standard bucket 10, which is provided with a tilt cylinder 48, which is a hydraulic actuator for controlling the tilt angle, and a rotary motor 50, which is a hydraulic actuator for controlling the rotary angle. A posture sensor 26E for measuring the tilt angle and rotary angle of the tiltrotator bucket 46 is attached to the rotating portion of the tiltrotator bucket 46. The left and right interlocking tilt cylinders 48 are swung up and down by operation of the operator, causing the tiltrotator bucket 46 to swing left and right about the tilt axis 47. The rotary motor 50 is also rotated 360 degrees by operation of the operator, causing the tiltrotator bucket 46 to rotate about the tiltrotator rotation axis 49. By making full use of these mechanisms, the excavator can flexibly respond to a target excavation surface 42 that is composed of multiple planes.

[0021] In this embodiment, it is assumed that mechanical angle sensors such as potentiometers are used as the attitude sensors 26A to 26E, but an inertial measurement unit (IMU) may also be used.

[0022] The actuators 5 to 7, 23, 48, and 50 are provided with actuator speed sensors 5S, 6S, 7S, 23S, 48S, and 50S that detect the speeds of the actuators 5 to 7, 23, 48, and 50. The actuator speed sensors 5S, 6S, 7S, 23S, 48S, and 50S are composed of a rotation angle sensor, a stroke sensor, and the like.

[0023] 3, the control device 28 includes a working point coordinate calculation unit 32, a target point coordinate calculation unit 33, a working point deviation calculation unit 34, a working point velocity vector calculation unit 35, an actuator target velocity calculation unit 36, and an actuator control unit 37. The control device 28 includes a calculation unit such as a CPU, storage devices such as a ROM and RAM, an input / output interface for inputting and outputting signals to and from external devices, and the functions of each unit are realized by executing a program stored in the ROM or the like.

[0024] Based on the posture information detected by the posture sensors 26A to 26E and the coordinates of at least two points within the components of the work implement that the operator has set as multiple working points 30 via a user interface (input device) 29, the working point coordinate calculation unit 32 calculates the coordinates of each of working points 44a, 44b specified as multiple working points 30 in a global coordinate system or a local coordinate system based on the work machine, and transmits these coordinates to the target point coordinate calculation unit 33 and the working point deviation calculation unit 34. A specific method for setting each of the working points 44a, 44b will be described later.

[0025] Based on the coordinates of each working point 44a, 44b calculated by the working point coordinate calculation unit 32 and the design information 31 of the construction object input via the user interface 29, the target point coordinate calculation unit 33 calculates the coordinates of the point where the distance between each working point 44a, 44b and the target excavation surface 42 is shortest (the position where the arrival time is shortest) in a global coordinate system or a local coordinate system based on the work machine, and transmits these as target points 45a, 45b to the working point deviation calculation unit 34. A specific method for calculating each target point 45a, 45b will be described later.

[0026] The work point deviation calculation unit 34 calculates the absolute value of the deviation between the coordinates of each work point 44a, 44b calculated by the work point coordinate calculation unit 32 and the coordinates of each target point 45a, 45b calculated by the target point coordinate calculation unit 33, and transmits it to the work point velocity vector calculation unit 35.

[0027] The working point velocity vector calculation unit 35 generates velocity vectors 41a, 41b directed toward each target point 45a, 45b for each working point 44a, 44b from the absolute values ​​of the deviations between each working point 44a, 44b and each target point 45a, 45b calculated by the working point deviation calculation unit 34, and transmits these to the actuator target velocity calculation unit 36. The velocity vectors 41a, 41b can be obtained by dividing the deviations between each working point 44a, 44b and each target point 45a, 45b by the control period of the control device 28.

[0028] The actuator target velocity calculation unit 36 ​​calculates the target velocity of each actuator based on the velocity vectors 41a, 41b of each working point 44a, 44b calculated by the working point velocity vector calculation unit 35, and transmits the calculated target velocity to the actuator control unit 37. Here, there is a method for calculating the target velocity of the actuator so as to minimize the deviation between each working point 44a, 44b and each target point 45a, 45b by using the deviation between each working point 44a, 44b and each target point 45a, 45b as an evaluation function, such as in model predictive control (MPC).

[0029] The actuator control unit 37 operates the control valves of the actuators 5 to 7, 23, 48, and 50 based on the target speeds of the actuators 5 to 7, 23, 48, and 50 calculated by the actuator target speed calculation unit 36, and matches the speeds of the actuators 5 to 7, 23, 48, and 50 to the target speeds based on the responses of the actuators 5 to 7, 23, 48, and 50 calculated by the actuator speed sensors 5S, 6S, 7S, 23S, 48S, and 50S.

[0030] 4A to 4C are diagrams showing how the tiltrotator bucket 46 according to the first embodiment faces the target excavation surface on each plane.

[0031] First, a method for specifying the work points 44a and 44b will be described. Input to the control device 28 is performed by preparing a user interface 29 having a device such as a touch monitor, and specifying two or more work points 30 on a schematic diagram of the tiltrotator bucket 46 displayed on the screen. As shown in FIGS. 4A to 4C , for example, one method is to prepare models of the tiltrotator bucket 46 in the x-z plane, x-y plane, and y-z plane, and specify the work points 44a and 44b on each plane. Alternatively, a 3D model of the tiltrotator bucket 46 may be prepared, and the work points 44a and 44b may be specified by moving or rotating the 3D model. Furthermore, while it is possible to select two or more work points 44a and 44b, the calculation load on the control device 28 increases as the number of work points 44a and 44b increases, and therefore the limit on the number of work points 44a and 44b that can be specified is determined by the computing power of the control device 28. Note that if it is difficult to specify two or more work points 44a, 44b for some reason, care must be taken because, depending on the shape of the target excavation surface 42, it may not be possible to generate the expected operation.

[0032] Next, a method for calculating the target points 45a, 45b will be described. First, based on information about the target excavation surface 42, the shortest distance from each of the working points 44a, 44b to the target excavation surface 42 is calculated while maintaining the distance between each of the working points 44a, 44b at the current time. Here, the shortest distance does not simply mean the shortest distance, but also includes a position that can be reached in the shortest time, taking into consideration the structure of the driven member, the operating characteristics of each actuator, and the characteristics of each actuator, such as the operating trajectory of the driven member (for example, linear operation, arcuate operation, etc.).

[0033] Specifically, assuming that the x-coordinate, y-coordinate, and z-coordinate of working point 44a are Xax, X_ay, and X_az, respectively, the x-coordinate, y-coordinate, and z-coordinate of working point 44b are Xbx, Xby, and Xbz, respectively, and further that the x-coordinate, y-coordinate, and z-coordinate of target point 45a are ξax, ξay, and ξaz, respectively, and the x-coordinate, y-coordinate, and z-coordinate of target point 45b are ξbx, ξby, and ξbz, respectively, target points 45a and 45b are set so that the sum (equation 2) of the absolute value of the deviation between working point 44a and target point 45a and the absolute value of the deviation between working point 44b and target point 45b is smallest under the condition that the distance between working points 44a and 44b is equal to the distance between target points 45a and 45b (equation 1).

[0034]

[0035]

[0036] Next, the calculation process of the working point deviation calculation unit 34 and the method of generating the velocity vectors 41a, 41b will be described. Similar to the target point coordinate calculation unit 33, the working point deviation calculation unit 34 calculates each deviation between the working points 44a, 44b and the target points 45a, 45b. The working point velocity vector calculation unit 35 generates velocity vectors 41a, 41b at each working point 44a, 44b by dividing each deviation calculated by the working point deviation calculation unit 34 by the control period. Note that, as a method for further improving control performance, there is a method for calculating the deviation between the working points 44a, 44b and the target points 45a, 45b for N steps of the control period and adjusting the velocity vectors 41a, 41b. Specifically, this method predicts the position to which the current working points 44a, 44b will move after N control cycle steps, and adjusts the velocity vectors 41a, 41b so as to reduce the difference between the working points 44a, 44b and the target points 45a, 45b after N control cycle steps.

[0037] The actuator target velocity calculation unit 36 ​​integrates the multiple velocity vectors 41a and 41b obtained from the working point velocity vector calculation unit 35 to calculate the target velocities of the boom cylinder 5, arm cylinder 6, bucket cylinder 7, swing motor 23, tilt cylinder 48, and rotary motor 50. First, in the case of FIG. 4A , because the side of the tiltrotator bucket 46 is parallel to the x-z plane, priority is given to the operation of the boom cylinder 5, arm cylinder 6, and bucket cylinder 7 based on the velocity vectors 41a and 41b. On the other hand, in the case of FIG. 4B , it can be seen that velocity vector 41a is greater than velocity vector 41b. In other words, because the movement amount of working point 44a of the tiltrotator bucket 46 is greater than that of working point 44b, rotational operation around the z-axis (in this case, rotary operation) is required. Here, because it is difficult for the operation of the swing motor 23 to move working points 44a and 44b to reach target points 45a and 45b, priority is given to the operation of the rotary motor 50. Furthermore, in this case, in addition to the swing motor 23 and rotary motor 50, similar control is performed on the actuators among the boom cylinder 5, arm cylinder 6, bucket cylinder 7, and tilt cylinder 48 that can move the working points 44a and 44b on the x-y plane, and control is performed to prioritize the operation of the actuator that is optimal for moving the working points 44a and 44b to the target points 45a and 45b. In the case of FIG. 4C , as in the case of FIG. 4B , it can be seen that the velocity vector 41a of the working point 44a is greater than the velocity vector 41b of the working point 44b. In other words, because the working point 44a of the tiltrotator bucket 46 has a greater amount of movement than the working point 44b, a rotational movement about the x-axis (a tilting movement in this case) is required. Because it is difficult to move the working points 44a and 44b to the target points 45a and 45b using the combined operation of the boom cylinder 5, arm cylinder 6, and bucket cylinder 7, the tilting movement of the tilt cylinder 48 is prioritized.In this case, similar control is performed on the actuators that can move the working points 44a, 44b on the zy plane, including the boom cylinder 5, arm cylinder 6, bucket cylinder 7, and tilt cylinder 48, as well as the rotary motor 50 and the swing motor 23, and control is performed so that the optimal actuator is given priority and operated to move the working points 44a, 44b to the target points 45a, 45b.

[0038] FIG. 5 is a flowchart showing the processing contents of the control device according to the first embodiment.

[0039] 5 , the operator designates working points 44a, 44b as the plurality of working points 30 via the user interface 29 (step S110), and the operator inputs design information 31 via the user interface 29 (step S120). The control device 28 detects the orientation of each actuator using an inertial measurement unit, a rotation angle sensor, a stroke sensor, etc. (step S130), and calculates the coordinates of the working points 44a, 44b designated in step S110 (step S140). Based on the coordinates of the working points 44a, 44b calculated in step S140, the control device 28 calculates the coordinates of target points 45a, 45b (step S150), calculates the deviations between each working point 44a, 44b and each target point 45a, 45b (step S160), and generates velocity vectors 41a, 41b directed from each working point 44a, 44b to each target point 45a, 45b (step S170). The speeds of the actuators (swing motor 23, rotary motor 50, and other actuators in FIG. 4B ; boom cylinder 5, arm cylinder 6, bucket cylinder 7, tilt cylinder 48, and other actuators in FIG. 4C ) are calculated based on the generated velocity vectors 41 a, 41 b (step S180), and the actuators are operated (step S190). Through the above processing, the tiltrotator bucket 46 can be caused to face directly at and reach the target excavation surface 42.

[0040] (Summary) In the first embodiment, the system includes a lower traveling body 20, an upper rotating body 22 rotatably attached to the lower traveling body 20, an articulated working machine 24 rotatably attached to the upper rotating body 22 in the vertical direction and equipped with a working implement 46 having three degrees of freedom of rotation at its tip, a plurality of actuators 5 to 7, 23, 48, 50 that drive the articulated working machine 24, and actuator speed sensors 5S, 6S, 7S, 23S, 48S, 50 that detect the speeds of the plurality of actuators 5, 6, 7, 23, 48, 50. In the working machine 100, the working machine 100 is equipped with a rotating body 22 and an articulated work implement 24, attitude sensors 26A to 26E that detect the attitudes of the rotating body 22 and the articulated work implement 24, and a control device 28 that controls a plurality of actuators 5, 6, 7, 23, 48, 50. The control device 28 includes a working point coordinate calculation unit 32 that calculates the coordinates of a plurality of working points 44a, 44b set on the work implement 46 based on the detected values ​​of the attitude sensors 26A to 26E, and a control device 28 that calculates the coordinates of a plurality of target points 45a, 45b corresponding to the plurality of working points 44a, 44b. a working point deviation calculation unit 34 for calculating deviations between the coordinates of the plurality of working points 44a, 44b calculated by the working point coordinate calculation unit 32 and the coordinates of the plurality of target points 45a, 45b calculated by the target point coordinate calculation unit 33; a working point velocity vector calculation unit 35 for calculating velocity vectors 41a, 41b of the plurality of working points 44a, 44b so that the sum of the absolute values ​​of the deviations calculated by the working point deviation calculation unit 34 becomes small; The actuator control unit 37 controls the actuators 5, 6, 7, 23, 48, and 50 so that the target speeds calculated by the actuator target speed calculation unit 36 ​​coincide with the speeds detected by the actuator speed sensors 5S, 6S, 7S, 23S, 48S, and 50S.

[0041] According to the first embodiment configured as described above, the operation of facing the work tool 46, which has three degrees of rotational freedom, directly toward the target excavation surface 42 and the operation of making the work tool 46 reach the target excavation surface 42 are performed simultaneously in parallel, making it possible to quickly excavate along the target excavation surface 42 while facing the work tool 46 directly toward the target excavation surface 42.

[0042] In the first embodiment, the plurality of working points 44a, 44b set on the work tool 46 include a first working point 44a and a second working point 44b, and the plurality of target points 45a, 45b corresponding to the plurality of working points 44a, 44b, respectively, include a first target point 45a corresponding to the first working point 44a and a second target point 45b corresponding to the second working point 44b, and the target point coordinate calculation unit 33 sets the first target point 45a and the second target point 45b so that the distance between the first target point 45a and the second target point 45b is equal to the distance between the first working point 44a and the second working point 44b and so that the sum of the absolute value of the deviation between the first working point 44a and the first target point 45a and the absolute value of the deviation between the second working point 44b and the second target point 45b is minimum. This makes it possible to have the tip of the work tool 46 directly face and reach the target excavation surface 42 as quickly as possible.

[0043] A second embodiment of the present invention will be described with reference to FIGS.

[0044] In the first embodiment, the operator specified the positions of the working points 44a, 44b via the user interface 29, but in this embodiment, the tiltrotator bucket 46 is aligned with the toe direction specified by the operator via the user interface (input device) 29, and excavation is performed quickly along the target excavation surface 42 while facing the tiltrotator bucket 46 directly toward the target excavation surface 42.

[0045] Fig. 6 is a functional block diagram showing a part of the processing functions of the control device 28 mounted on the hydraulic excavator 100 in the second embodiment. Fig. 7 is a schematic diagram showing a method for setting a target point in the second embodiment. Fig. 8 is a flowchart showing the processing contents of the control device in the second embodiment. In the figures, the same components as those in the first embodiment are given the same reference numerals, and their explanations will be omitted.

[0046] As shown in FIG. 6 , the operator uses the user interface 29 to input the toe direction of the tiltrotator bucket 46, which is the desired direction of movement (requested direction). Specifically, for input to the control device 28, a user interface 29 having a device such as a touch monitor is prepared, and the toe direction of the tiltrotator bucket 46 is specified on a schematic diagram of the tiltrotator bucket 46 displayed on the screen. For example, one method is to prepare a model of the tiltrotator bucket 46 on the xy plane, and have the operator refer to an overhead video image to specify the toe direction of the tiltrotator bucket 46 on the xy plane. Alternatively, a 3D model of the tiltrotator bucket 46 may be prepared, and the toe direction of the tiltrotator bucket 46 may be specified while moving or rotating the 3D model of the tiltrotator bucket 46.

[0047] In this embodiment, the working point coordinate calculation unit 32 calculates the coordinates of at least two working points 44a, 44b within a predetermined component of the tiltrotator bucket 46. Note that, since the calculation load on the control device 28 increases as the number of calculated working points 44a, 44b increases, a limit on the number of calculated working points 44a, 44b is determined based on the calculation capacity of the control device 28.

[0048] FIG. 7 is a schematic diagram showing a method for setting a target point according to the second embodiment.

[0049] As shown in FIG. 7 , target point coordinate calculation unit 33 calculates the coordinates of each of target points 45 a, 45 b based on toe direction 51 of tiltrotator bucket 46 and design information 31 obtained from user interface 29, and the coordinates of at least two working points 44 a, 44 b within the constituent members of tiltrotator bucket 46 calculated by working point coordinate calculation unit 32. Specifically, the tiltrotator bucket 46 is virtually rotated so that the cutting edge direction of the tiltrotator bucket 46 coincides with the toe direction 51 specified via the user interface 29, and each of the working points 44a, 44b on the virtually rotated tiltrotator bucket 46 is set as virtual working points 44aX, 44bX, and the first target point 45a and the second target point 45b are set so that the distance between the first target point 45a and the second target point 45b is equal to the distance between the first virtual working point 44aX and the second virtual working point 44bX and so that the sum of the absolute value of the deviation between the first virtual working point 44aX and the first target point 45a and the absolute value of the deviation between the second virtual working point 44bX and the second target point 45b is minimum.

[0050] The other configurations are the same as those of the first embodiment.

[0051] FIG. 8 is a flowchart showing the processing contents of the control device according to the second embodiment.

[0052] 8 , the operator specifies the toe direction of the tiltrotator bucket 46 via the user interface 29 (step S210), and the operator inputs design information 31 via the user interface 29 (step S220). The control device 28 detects the attitude of each actuator using an inertial measurement unit, a rotation angle sensor, a stroke sensor, etc. (step S230), and calculates the coordinates of a plurality of predetermined working points 44 a, 44 b (step S240). Based on the coordinates of the working points 44a, 44b calculated in step S240, the toe direction of the tiltrotator bucket 46 obtained in step S210, and the design information 31 obtained in step S220, the coordinates of the target points 45a, 45b are calculated (step S250), the deviations between each of the working points 44a, 44b and each of the target points 45a, 45b are calculated (step S260), and velocity vectors 41a, 41b directed from each of the working points 44a, 44b to each of the target points 45a, 45b are generated (step S270). The velocities of multiple actuators are calculated based on the generated velocity vectors 41a, 41b (step S280), and optimal actuators are operated to move the working points 44a, 44b toward the target points 45a, 45b (step S290).

[0053] (Summary) In the second embodiment, the work machine 100 is provided with an input device 29 that specifies the toe direction of the work implement 46, the multiple working points 44a, 44b set on the work implement 46 include a first working point 44a and a second working point 44b, the multiple target points 45a, 45b corresponding to the multiple working points 44a, 44b respectively include a first target point 45a corresponding to the first working point 44a and a second target point 45b corresponding to the second working point 44b, and the target point coordinate calculation unit 33 calculates the toe direction of the work implement 46 so that it coincides with the toe direction 51 specified by the input device 29. The work tool 46 is virtually rotated, and the first working point 44a and the second working point 44b on the virtually rotated work tool 46 are set as a first virtual working point 44aX and a second virtual working point 44bX. The first target point 45a and the second target point 45b are set so that the distance between the first target point 45a and the second target point 45b is equal to the distance between the first virtual working point 44aX and the second virtual working point 44bX, and so that the sum of the absolute value of the deviation between the first virtual working point 44aX and the first target point 45a and the absolute value of the deviation between the second virtual working point 44bX and the second target point 45b is minimum.

[0054] According to the second embodiment configured as described above, it is possible to align the toe direction of the work tool 46, which has three degrees of rotational freedom, in the direction intended by the operator, and to quickly excavate along the target excavation surface 42 by facing the tip of the work tool 46 directly toward the target excavation surface 42 as quickly as possible.

[0055] A third embodiment of the present invention will be described with reference to FIGS.

[0056] In the second embodiment, the operator specified the tiptoe direction of the tiltrotator bucket 46 via the user interface 29, but in this embodiment, based on design information 31 of the construction target and a movement path 53 of the tiltrotator bucket 46 obtained from an input unit 52 of not only the user interface 29 but also another control device or the like, the tiltrotator bucket 46 is moved along the movement path 53, and excavation is performed quickly along the target excavation surface 42 while the tiltrotator bucket 46 is positioned directly against the target excavation surface 42.

[0057] Fig. 9 is a functional block diagram showing a part of the processing function of the control device of the hydraulic excavator according to the third embodiment. Fig. 10 is a flowchart showing the processing contents of the control device according to the third embodiment. In the drawings, the same reference numerals are used to designate the same members as those in the first and second embodiments, and the description thereof will be omitted.

[0058] As shown in FIG. 9 , the control device 28 acquires a movement path 53 and design information input by the operator as the path (trajectory) along which the operator wants to move the bucket 46 via an input unit 52, such as a user interface 29 or another control device. The target point coordinate calculation unit 33 calculates multiple target points along the path based on the acquired movement path 53 and the design information. The movement path 53 is composed of two points, a work start point and a work end point, or a work start point, a work end point, and one or more relay points. The target point coordinate calculation unit 33 calculates target points 45 a, 45 b corresponding to each of the work points 44 a, 44 b for each of the work start point, work end point, and relay point within the movement path 53, establishes virtual relay points according to the control cycle of the control device 28, and sets target points 45 a, 45 b for each virtual relay point.

[0059] FIG. 10 is a flowchart showing the processing contents of the control device according to the third embodiment.

[0060] 10, the control device 28 acquires the motion path 53 from the input unit 52 of the user interface 29, another control device, or the like (step S310), and acquires design information from the input unit 52 of the user interface 29, another control device, or the like (step S320).The control device 28 detects the orientation of each actuator using an inertial measurement unit, a rotation angle sensor, a stroke sensor, or the like (step S330), and calculates the coordinates of a plurality of predetermined working points 44a, 44b (step S340). Based on the coordinates of the working points 44a, 44b calculated in step S340, the motion path 53 obtained in step S310, and the design information 31 obtained in step S320, the coordinates of the target points 45a, 45b are calculated (step S350), the deviations between each working point 44a, 44b and each target point 45a, 45b are calculated (step S360), and velocity vectors 41a, 41b directed from each working point 44a, 44b to each target point 45a, 45b are generated (step S370). The velocity of the actuator is calculated based on each generated velocity vector 41a, 41b (step S380), and the actuator is operated (step S390).

[0061] The other configurations are the same as those of the first and second embodiments.

[0062] (Summary) In the third embodiment, the target point coordinate calculation unit 33 acquires the movement path 53 of the work tool 46 and the design information 31 of the construction target, sets a virtual relay point on the movement path 53 according to the control cycle of the control device 28, and sets target points 45a, 45b at the start point of the movement path 53, the virtual relay point, and the end point of the movement path 53, respectively, based on the design information 31.

[0063] According to the third embodiment configured as described above, it is possible to move the work tool 46, which has three rotational degrees of freedom, along the operating path 53, and quickly face the work tool 46 directly toward the target excavation surface 42, thereby quickly performing excavation along the target excavation surface 42.

[0064] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments are presented to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0065] 2...cab, 2a, 2b...operating levers, 3...travel motor (actuator), 5...boom cylinder (actuator), 5S...actuator speed sensor, 6...arm cylinder (actuator), 6S...actuator speed sensor, 7...bucket cylinder (actuator), 7S...actuator speed sensor, 8...boom, 9...arm, 10...bucket (work implement), 20...lower traveling body, 21...swing mechanism, 22...upper swing body, 23...swing motor (actuator), 23S...actuator speed sensor, 24...front working implement, 25...swing central axis, 26A to 26E...attitude sensors, 27...swing center, 28...control device, 29...user interface (input device), 32...working point coordinate calculation unit, 33...target point coordinate calculation unit, 34...working point deviation calculation unit , 35...working point velocity vector calculation unit, 36...actuator target velocity calculation unit, 37...actuator control unit, 41a, 41b...velocity vector, 42...target excavation surface, 44a...working point (first working point), 44aX...virtual working point (first virtual working point), 44b...working point (second working point), 44bX...virtual working point (second virtual working point), 45a...target point (first target point), 45b...target point (second target point), 46...tiltrotator bucket (work tool), 47...tilt axis, 48...tilt cylinder (actuator), 48S...actuator speed sensor, 49...tiltrotator rotate axis, 50...rotary motor (actuator), 50S...actuator speed sensor, 51...toe direction, 52...input unit, 53...motion path, 100...hydraulic excavator (work machine).

Claims

1. A work machine comprising: a lower traveling body; an upper rotating body rotatably attached on said lower traveling body; an articulated work machine attached to said upper rotating body so as to be rotatable in the vertical direction and equipped with a work implement having three degrees of freedom of rotation at its tip; a plurality of actuators for driving said articulated work machine; actuator speed sensors for detecting the speeds of said plurality of actuators; an attitude sensor for detecting the attitude of said upper rotating body and said articulated work machine; and a control device for controlling said plurality of actuators, wherein said control device comprises: a working point coordinate calculation unit for calculating the coordinates of a plurality of working points set on said implement based on detection values ​​of said attitude sensor; a target point coordinate calculation unit for calculating the coordinates of a plurality of target points respectively corresponding to said plurality of working points; a working point deviation calculation unit for calculating the absolute value of each deviation between the coordinates of the plurality of working points calculated by said working point coordinate calculation unit and the coordinates of the plurality of target points calculated by said target point coordinate calculation unit; and a working point velocity vector calculation unit for calculating each velocity vector of the plurality of working points so as to minimize the sum of the absolute values ​​of the deviations calculated by said working point deviation calculation unit. a target actuator velocity calculation unit that calculates a target velocity for each of the plurality of actuators based on the velocity vectors of each of the plurality of working points calculated by the working point velocity vector calculation unit; and an actuator control unit that controls the plurality of actuators so that the target velocity calculated by the target actuator velocity calculation unit matches the velocity detected by the actuator velocity sensor.

2. A work machine as described in claim 1, wherein the plurality of work points include a first work point and a second work point, and the plurality of target points include a first target point corresponding to the first work point and a second target point corresponding to the second work point, and the target point coordinate calculation unit sets the first target point and the second target point so that the distance between the first target point and the second target point is equal to the distance between the first work point and the second work point, and the sum of the absolute value of the deviation between the first work point and the first target point and the absolute value of the deviation between the second work point and the second target point is minimum.

3. A work machine according to claim 1, further comprising an input device for specifying the toe direction of the work implement, wherein the plurality of work points include a first work point and a second work point, and the plurality of target points include a first target point corresponding to the first work point and a second target point corresponding to the second work point, and wherein the target point coordinate calculation unit virtually rotates the work implement so that the toe direction of the work implement coincides with the toe direction specified by the input device, sets the first working point and the second working point on the virtually rotated work implement as a first virtual working point and a second virtual working point, and sets the first target point and the second target point so that the distance between the first target point and the second target point is equal to the distance between the first virtual working point and the second virtual working point, and so that the sum of the absolute value of the deviation between the first virtual working point and the first target point and the absolute value of the deviation between the second virtual working point and the second target point is minimum.

4. A work machine as described in claim 3, wherein the target point coordinate calculation unit acquires design information for the movement path of the work tool and the work target, sets virtual relay points on the movement path according to the control cycle of the control device, and sets the target points at the start point of the movement path, the virtual relay points, and the end point of the movement path based on the design information.

Images