System and method for controlling a working machine

Abstract

The measurement value acquisition unit acquires measurement values ​​from a plurality of sensors. The attitude calculation unit calculates the attitude of the attachment relative to the vehicle body based on the measurement values. The intervention control unit determines a virtual rotation axis based on the calculated attitude of the attachment. The operation signal acquisition unit acquires an operation signal from an operation device to operate the support member. Based on the calculated attitude of the attachment and the amount of operation indicated by the operation signal to operate the support member, the intervention control unit generates a control signal for a tilt rotator to rotate the attachment around the virtual axis rotation so that the axial direction of the virtual rotation axis in the global coordinate system is maintained and the design plane and the cutting edge of the attachment are in close proximity to each other. The output unit outputs the generated control signal.

Description

Technology Field

[0001] The present disclosure relates to a system and method for controlling a working machine.

[0002] The present application claims priority to Patent Application No. 2021-161376 filed in Japan on September 30, 2021, and incorporates the contents thereof herein by reference. Background Technology

[0003] Patent Document 1 discloses a technique for moving a bucket along an inclined design plane in a working machine equipped with a tilt bucket capable of tilting the angle of the teeth of the bucket. The tilt axis of the tilt bucket extends in the direction of the opening of the bucket. Prior art literature

[0004] International Publication No. 2016 / 186219 The problem to be solved

[0005] However, a component called a tilt rotator is known that supports the attachment of a work machine so that it can rotate around three mutually orthogonal axes. By equipping the work machine with a tilt rotator, the attachment can be directed in any direction. However, while the tilt rotator has a high degree of freedom of rotation, it becomes difficult to operate by an operator. Patent Document 1 can automate the movement around the tilt axis, but it does not disclose the control of a work machine equipped with a tilt rotator.

[0006] The object of the present disclosure is to provide a system and a method capable of supporting the operation of a work machine having an attachment supported on a support member through a tilt rotator. means of solving the problem

[0007] According to one aspect of the present disclosure, the system comprises a processor for controlling a work machine having a support member movably supported on a vehicle body, a tilt rotator mounted on the tip of the support member, and an attachment having a cutting edge and rotatably supported around three axes intersecting the support member in different planes through the tilt rotator. The processor acquires measurement values ​​from a plurality of sensors. Based on the measurement values, the processor calculates the orientation of the attachment relative to the vehicle body. Based on the calculated orientation of the attachment, the processor determines a virtual rotation axis. Based on the calculated orientation of the attachment and the amount of operation indicated by the operation signal for operating the support member, the processor generates a control signal for the tilt rotator to maintain the axial direction of the virtual rotation axis in a global coordinate system and to rotate the attachment around the virtual rotation axis so that the cutting edge of the attachment is in close proximity to the design plane, and outputs the generated control signal. Effects of the invention

[0008] According to the above description, the system can support the operation of a work machine having an attachment supported on a support member through a tilt rotator. Brief explanation of the drawing

[0009] [Fig. 1] This is a schematic diagram showing the configuration of a work machine related to the first embodiment. [Fig. 2] This is a drawing showing the configuration of a tilt rotator related to the first embodiment. [Fig. 3] This is a drawing showing the drive system of a work machine related to the first embodiment. [Fig. 4] This is a schematic block diagram showing the configuration of a control device related to the first embodiment. [Fig. 5] This is a flowchart (Part 1) showing the intervention control of the working machine in the first embodiment. [Fig. 6] This is a flowchart (Part 2) showing the intervention control of the working machine in the first embodiment. [Fig. 7] This is a flowchart showing the edge alignment control in the first embodiment. [Fig. 8] This is a flowchart showing design plane tracking control in the first embodiment. Specific details for implementing the invention

[0010] <First Embodiment>

[0011] Components of the working machine

[0012] Hereinafter, embodiments will be described in detail with reference to the drawings.

[0013] FIG. 1 is a schematic diagram showing the configuration of a work machine (100) related to a first embodiment. The work machine (100) related to the first embodiment is, for example, a hydraulic shovel. The work machine (100) is equipped with a driving body (120), a rotating body (140), a working device (160), a driver's cab (180), and a control device (200). The work machine (100) related to the first embodiment controls the cutting edge of the bucket (164) so ​​that it does not extend beyond the design plane.

[0014] The driving body (120) supports the working machine (100) so that it can be driven. The driving body (120) is, for example, a pair of left and right tracks.

[0015] The pivot body (140) is supported on the driving body (120) so as to be pivotable around the pivot center. The pivot body (140) is an example of a vehicle body. The driving body (120) is an example of a base that supports the pivot body (140) so as to be pivotable.

[0016] The workpiece (160) is movably supported on the slewing body (140). The workpiece (160) is driven by hydraulics. The workpiece (160) is equipped with a boom (161), an arm (162), a tilt rotator (163), and a bucket (164) which is an attachment. The base end of the boom (161) is rotatably mounted on the slewing body (140). The base end of the arm (162) is rotatably mounted on the tip end of the boom (161). The tilt rotator (163) is rotatably mounted on the tip end of the arm (162). The bucket (164) is mounted on the tilt rotator (163). The bucket (164) is rotatably supported around three axes that intersect in different planes relative to the workpiece (160) via the tilt rotator (163). Here, the part of the slewing body (140) on which the work tool (160) is mounted is called the front part. Also, with respect to the front part of the slewing body (140), the part on the opposite side is called the rear part, the part on the left is called the left part, and the part on the right is called the right part. The boom (161) and the arm (162) are examples of support parts that are movably supported on the slewing body (140).

[0017] FIG. 2 is a drawing showing the configuration of a tilt rotator (163) related to a first embodiment. The tilt rotator (163) is mounted on the tip of an arm (162) to support a bucket (164). The tilt rotator (163) comprises a mounting part (1631), a tilt part (1632), and a rotation part (1633). The mounting part (1631) is mounted on the tip of the arm (162) so as to be rotatable around an axis extending in the left-right direction shown. The tilt part (1632) is mounted on the mounting part (1631) so as to be rotatable around an axis extending in the front-back direction shown. The rotation part (1633) is mounted on the tilt part (1632) so as to be rotatable around an axis extending in the up-down direction shown. Ideally, the rotation axes of the mounting part (1631), the tilt part (1632), and the rotation part (1633) are orthogonal to each other. The base of the bucket (164) is fixed to the rotating part (1633). Thus, the bucket (164) can rotate around three mutually orthogonal axes with respect to the arm (162). However, in reality, the rotation axes of the mounting part (1631), the tilt part (1632), and the rotating part (1633) may include design errors and may not necessarily be orthogonal.

[0018] The operator's cab (180) is installed in the entire slewing body (140). Inside the operator's cab (180), an operating device (271) for an operator to operate the work machine (100) and a monitor device (272), which is a human-machine interface of the control device (200), are installed. The operating device (271) receives input from the operator regarding the amount of operation of the travel motor (304), the amount of operation of the slewing motor (305), the amount of operation of the boom cylinder (306), the amount of operation of the arm cylinder (307), the amount of operation of the bucket cylinder (308), the amount of operation of the tilt cylinder (309), and the amount of operation of the rotary motor (310). The operating device (271) outputs an operation signal indicating the amount of operation of the work machine. The operating device (271) is operated by the operator and outputs an operation signal to operate the boom (161) and the arm (162). The control device (271) is operated by an operator and outputs a control signal to rotate the turning body (140) relative to the driving body (120). The control device (271) is operated by an operator and outputs a control signal to operate the tilt rotator (163). The monitor device (272) receives input from the operator for setting and releasing the bucket attitude maintenance mode. The bucket attitude maintenance mode is a mode in which the control device (200) automatically controls the bucket cylinder (308), the tilt cylinder (309), and the rotation motor (310) to maintain the attitude of the bucket (164) in the global coordinate system. The monitor device (272) is implemented, for example, by a computer equipped with a touch panel.

[0019] The control device (200) controls the vehicle body (120), the slewing body (140), and the work machine (160) based on the operation of the operating device (271) by an operator. The control device (200) is installed, for example, inside the driver's cabin (180).

[0020] Drive system of the work machine (100)

[0021] FIG. 3 is a drawing showing the drive system of a work machine (100) related to the first embodiment.

[0022] The work machine (100) is equipped with a plurality of actuators for driving the work machine (100). Specifically, the work machine (100) is equipped with an engine (301), a hydraulic pump (302), a control valve (303), a pair of driving motors (304), a slewing motor (305), a boom cylinder (306), an arm cylinder (307), a bucket cylinder (308), a tilt cylinder (309), and a rotary motor (310).

[0023] The engine (301) is a prime mover that drives the hydraulic pump (302).

[0024] The hydraulic pump (302) is driven by the engine (301) and supplies hydraulic fluid to the drive motor (304), slewing motor (305), boom cylinder (306), arm cylinder (307) and bucket cylinder (308) through the control valve (303).

[0025] The control valve (303) controls the flow rate of the hydraulic fluid supplied from the hydraulic pump (302) to the drive motor (304), slewing motor (305), boom cylinder (306), arm cylinder (307) and bucket cylinder (308).

[0026] The driving motor (304) is driven by hydraulic fluid supplied from the hydraulic pump (302) and drives the driving body (120).

[0027] The slewing motor (305) is driven by hydraulic fluid supplied from the hydraulic pump (302) and slewing the slewing body (140) relative to the driving body (120).

[0028] The boom cylinder (306) is a hydraulic cylinder for driving the boom (161). The base end of the boom cylinder (306) is mounted on the slewing body (140). The front end of the boom cylinder (306) is mounted on the boom (161).

[0029] The arm cylinder (307) is a hydraulic cylinder for driving the arm (162). The base end of the arm cylinder (307) is mounted on the boom (161). The front end of the arm cylinder (307) is mounted on the arm (162).

[0030] The bucket cylinder (308) is a hydraulic cylinder for driving the tilt rotator (163) and the bucket (164). The base end of the bucket cylinder (308) is mounted on the arm (162). The front end of the bucket cylinder (308) is mounted on the tilt rotator (163) via a link member.

[0031] The tilt cylinder (309) is a hydraulic cylinder for driving the tilt section (1632). The base end of the tilt cylinder (309) is mounted on the mounting section (1631). The front end of the tilt cylinder (309) is mounted on the tilt section (1632).

[0032] The rotary motor (310) is a hydraulic motor for driving the rotating part (1633). The bracket and stator of the rotary motor (310) are fixed to the tilt part (1632). The rotation axis and rotor of the rotary motor (310) are installed to extend in the vertical direction shown and are fixed to the rotating part (1633).

[0033] "Measuring instrument of the working machine (100)"

[0034] The work machine (100) is equipped with a plurality of sensors for measuring the posture, orientation, and position of the work machine (100). Specifically, the work machine (100) is equipped with an inclination measuring device (401), a position orientation measuring device (402), a boom angle sensor (403), a rock angle sensor (404), a bucket angle sensor (405), a tilt angle sensor (406), and a rotation angle sensor (407).

[0035] The inclination measuring device (401) measures the attitude of the turning body (140). The inclination measuring device (401) measures the inclination of the turning body (140) with respect to the horizontal plane (e.g., roll angle, pitch angle, and yaw angle). An example of the inclination measuring device (401) is an IMU (Inertial Measurement Unit). In this case, the inclination measuring device (401) measures the acceleration and angular velocity of the turning body (140) and calculates the inclination of the turning body (140) with respect to the horizontal plane based on the measurement results. The inclination measuring device (401) is installed, for example, below the driver's cab (180). The inclination measuring device (401) outputs the attitude data of the turning body (140), which is the measured value, to the control device (200).

[0036] The position and orientation measuring device (402) measures the position of a representative point of the rotating body (140) and the orientation toward which the rotating body (140) is facing by means of a GNSS (Global Navigation Satellite System). The position and orientation measuring device (402) is equipped with, for example, two GNSS antennas not shown mounted on the rotating body (140), and detects the orientation orthogonal to the straight line connecting the positions of the two antennas as the orientation toward which the working machine (100) is facing. The position and orientation measuring device (402) outputs the position data and orientation data of the rotating body (140), which are the measured values, to the control device (200).

[0037] The boom angle sensor (403) measures the boom angle, which is the angle of the boom (161) relative to the swivel body (140). The boom angle sensor (403) may be an IMU mounted on the boom (161). In this case, the boom angle sensor (403) measures the boom angle based on the inclination of the boom (161) relative to the horizontal plane and the inclination of the swivel body measured by the inclination measuring instrument (401). The measured value of the boom angle sensor (403) indicates zero, for example, when the direction of a straight line passing through the base and tip of the boom (161) coincides with the front-rear direction of the swivel body (140). Additionally, the boom angle sensor (403) related to another embodiment may be a stroke sensor mounted on the boom cylinder (306). Furthermore, the boom angle sensor (403) related to another embodiment may be a rotation sensor installed on an indirect axis that rotatably connects the swivel body (140) and the boom (161). The boom angle sensor (403) outputs boom angle data, which is a measured value, to the control device (200).

[0038] The arm angle sensor (404) measures the arm angle, which is the angle of the arm (162) relative to the boom (161). The arm angle sensor (404) may be an IMU mounted on the arm (162). In this case, the arm angle sensor (404) measures the arm angle based on the inclination of the arm (162) relative to the horizontal plane and the boom angle measured by the boom angle sensor (403). The measured value of the arm angle sensor (404) indicates zero, for example, when the direction of a straight line passing through the base and tip of the arm (162) matches the direction of a straight line passing through the base and tip of the boom (161). In addition, the arm angle sensor (404) related to another embodiment may calculate the angle by installing a stroke sensor on the arm cylinder (307). Furthermore, the arm angle sensor (404) related to another embodiment may be a rotation sensor installed on an articulation axis that rotatably connects the boom (161) and the arm (162). The rock angle sensor (404) outputs rock angle data, which is a measured value, to the control device (200).

[0039] The bucket angle sensor (405) measures the bucket angle, which is the angle of the tilt rotator (163) relative to the arm (162). The bucket angle sensor (405) may be a stroke sensor installed on the bucket cylinder (308). In this case, the bucket angle sensor (405) measures the bucket angle based on the stroke amount of the bucket cylinder (308). The measured value of the bucket angle sensor (405) indicates zero, for example, when the direction of a straight line passing through the base and tip of the bucket (164) matches the direction of a straight line passing through the base and tip of the arm (162). Furthermore, the bucket angle sensor (405) related to another embodiment may be a rotation sensor installed on an articulation axis that rotatably connects the arm (162) and the mounting part (1631) of the tilt rotator (163). Additionally, the bucket angle sensor (405) related to another embodiment may be an IMU mounted on the bucket (164). The bucket angle sensor (405) outputs the measured value, which is bucket angle data, to the control device (200).

[0040] The tilt angle sensor (406) measures the tilt angle, which is the angle of the tilt portion (1632) relative to the mounting portion (1631) of the tilt rotator (163). The tilt angle sensor (406) may be a rotation sensor installed on an articulation axis that rotatably connects the mounting portion (1631) and the tilt portion (1632). The measured value of the tilt angle sensor (406) indicates zero, for example, when the rotation axis of the arm (162) and the rotation axis of the rotation portion (1633) are orthogonal. In addition, the tilt angle sensor (406) related to other embodiments may calculate the angle by installing a stroke sensor on the tilt cylinder (309). The tilt angle sensor (406) outputs the measured tilt angle data to the control device (200).

[0041] The rotation angle sensor (407) measures the rotation angle, which is the angle of the rotation part (1633) relative to the tilt part (1632) of the tilt rotator (163). The rotation angle sensor (407) may be a rotation sensor installed on the rotation motor (310). The measured value of the tilt angle sensor (406) indicates zero, for example, when the direction in which the blade tip of the bucket (164) is facing becomes parallel to the operating plane of the work tool (160). The rotation angle sensor (407) outputs the measured rotation angle data to the control device (200).

[0042] Configuration of the control device (200)

[0043] FIG. 4 is a schematic block diagram showing the configuration of a control device (200) related to the first embodiment.

[0044] The control device (200) is a computer equipped with a processor (210), main memory (230), storage (250), and an interface (270). The control device (200) is an example of a control system. The control device (200) receives measurement values ​​from an inclination measuring instrument (401), a position orientation measuring instrument (402), a boom angle sensor (403), a rock angle sensor (404), a bucket angle sensor (405), a tilt angle sensor (406), and a rotation angle sensor (407).

[0045] Storage (250) is a type of non-temporary storage medium. Examples of storage (250) include magnetic disks, optical disks, magneto-optical disks, semiconductor memory, etc. Storage (250) may be an internal medium directly connected to the bus of the control device (200), or an external medium connected to the control device (200) through an interface (270) or a communication line. The operating device (271) and the monitor device (272) are connected to the processor (210) through the interface (270).

[0046] Storage (250) stores a control program for controlling the working machine (100). The control program may be intended to realize a part of the function to be performed by the control device (200). For example, the control program may be designed to perform a function by combining it with another program already stored in the storage (250), or by combining it with another program installed in another device. In addition, in another embodiment, the control device (200) may be equipped with a custom LSI (Large Scale Integrated Circuit), such as a PLD (Programmable Logic Device), in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions performed by the processor may be performed by the corresponding integrated circuit.

[0047] In the storage (250), geometric data is recorded indicating the dimensions and center of gravity locations of the slewing body (140), boom (161), arm (162), and bucket (164). Geometric data is data indicating the position of an object in a predetermined coordinate system. In addition, design surface data, which is three-dimensional data representing the shape of the design surface of a construction site in a global coordinate system, is recorded in the storage (250). The global coordinate system is X extending in the direction of latitude g Axis, Y extending in the direction of the primary election g Z extending in the axis and vertical direction g It is a coordinate system composed of axes. Design surface data is represented, for example, by TIN (Triangular Irregular Networks) data.

[0048] Software Configuration

[0049] The processor (210) executes a control program and is equipped with an operation signal acquisition unit (211), an input unit (212), a display control unit (213), a measurement value acquisition unit (214), a position attitude calculation unit (215), an intervention determination unit (216), an intervention control unit (217), and a control signal output unit (218).

[0050] The operation signal acquisition unit (211) acquires an operation signal indicating the amount of operation of each actuator from the operation device (271).

[0051] The input unit (212) receives operation input from the operator via the monitor device (272).

[0052] The display control unit (213) outputs screen data to be displayed on the monitor device (272) to the monitor device (272).

[0053] The measurement value acquisition unit (214) acquires measurement values ​​from an inclination measuring instrument (401), a position orientation measuring instrument (402), a boom angle sensor (403), a rock angle sensor (404), a bucket angle sensor (405), a tilt angle sensor (406), and a rotation angle sensor (407).

[0054] The position attitude calculation unit (215) calculates the position of the work machine (100) in the global coordinate system and the vehicle body coordinate system based on various measurement values ​​acquired by the measurement value acquisition unit (214) and geometric data recorded in the storage (250). For example, the position attitude calculation unit (215) calculates the position of the blade tip of the bucket (164) in the global coordinate system and the vehicle body coordinate system. The vehicle body coordinate system is an orthogonal coordinate system with the origin at the representative point of the turning body (140) (for example, a point passing through the turning center). The calculation of the position attitude calculation unit (215) will be described later. The position attitude calculation unit (215) is an example of an attitude calculation unit that calculates the attitude of the bucket (164) relative to the turning body (140).

[0055] The intervention determination unit (216) determines whether to limit the speed of the work machine (160) based on the position of the cutting edge of the bucket (164) calculated by the position attitude calculation unit (215) and the position relationship of the design surface indicated by the design surface data. Hereinafter, the control device (200) limiting the speed of the work machine (160) is also referred to as intervention control. Specifically, the intervention determination unit (216) calculates the shortest distance between the design surface and the bucket (164), and if the shortest distance is less than or equal to a predetermined distance, it determines to perform intervention control on the work machine (160).

[0056] When it is determined by the intervention judgment unit (216) that intervention control is to be performed, the intervention control unit (217) controls the amount of operation of the target of intervention among the amount of operation acquired by the operation signal acquisition unit (211). In the intervention control, the intervention control unit (217) controls the amount of operation of the boom (161) so that the working machine (160) does not intrude into the design line. As a result, the boom (161) operates so that the speed of the bucket (164) becomes a speed corresponding to the distance between the bucket (164) and the design line. That is, when the operator operates the arm (162) to perform excavation work, the intervention control unit (217) limits the speed of the cutting edge of the bucket (164) by raising the boom (161) according to the design plane.

[0057] The control signal output unit (218) outputs the amount of operation acquired by the operation signal acquisition unit (211) or the amount of operation controlled by the intervention control unit (217) to the control valve (303).

[0058] 《Calculation of position attitude calculation unit (215)》

[0059] Here, a method for calculating the position of a point on the outer shell of a work machine (100) by the position and posture calculation unit (215) is described. The position and posture calculation unit (215) calculates the position of a point on the outer shell based on various measurement values ​​acquired by the measurement value acquisition unit (214) and geometric data recorded in the storage (250). Geometric data indicating the dimensions of the slewing body (140), boom (161), arm (162), tilt rotator (163) (mounting part (1631), tilt part (1632) and rotating part (1633)) and bucket (164) is recorded in the storage (250).

[0060] The geometric data of the swivel body (140) is, in the local coordinate system, the vehicle body coordinate system, the center position (x) of the joint axis where the swivel body (140) supports the boom (161). bm , y bm , z bm It represents ). The vehicle body coordinate system is X extending in the forward and backward directions based on the turning center of the turning body (140). sb Axis, Y extending in the left-right direction sb Z extending in the axis and vertical direction sb It is a coordinate system composed of axes. Also, the vertical direction of the pivot body (140) does not necessarily coincide with the vertical direction.

[0061] The geometric data of the boom (161) is the position (x) of the joint axis where the boom (161) supports the arm (162) in the boom coordinate system, which is a local coordinate system. am , y am , z am ) represents. The boom coordinate system is based on the center position of the joint axis connecting the pivot body (140) and the boom (161), and X extending in the longitudinal direction. bm Axis, Y extending in the direction in which the joint axis extends bm Axis, X bm Axis and Y bm Z perpendicular to the axis bm It is a coordinate system composed of axes.

[0062] The geometric data of the arm (162) is, in the local coordinate system, the arm coordinate system, the position (x) of the joint axis where the arm (162) supports the mounting portion (1631) of the tilt rotator (163). t1 , y t1 , z t1 ) represents. The arm coordinate system is X extending in the longitudinal direction based on the center position of the joint axis connecting the boom (161) and the arm (162). am Axis, Y extending in the direction in which the joint axis extends am Axis, X am Axis and Y am Z perpendicular to the axis am It is a coordinate system composed of axes.

[0063] The geometric data of the mounting portion (1631) of the tilt rotator (163) is, in the first tilt-rotate coordinate system which is a local coordinate system, the position (x) of the joint axis where the mounting portion (1631) supports the tilt portion (1632). t2 , y t2 , z t2 ) and the inclination of the joint axis (φ t Represents ). Inclination of the joint axis φ t θ is an angle related to the design error of the tilt rotator (163) and is obtained through calibration of the tilt rotator (163), etc. The first tilt-rotate coordinate system is a Y-axis that extends in the direction in which the joint axis connecting the arm (162) and the mounting part (1631) extends, based on the center position of the joint axis connecting the arm (162) and the mounting part (1631). t1 Z extending in the direction in which the joint axis connecting the axis, mounting part (1631) and tilt part (1632) extends t1 Axis, and Y t1 Axis and Z t1 X perpendicular to the axis t1 It is a coordinate system composed of axes.

[0064] The geometric data of the tilt portion (1632) of the tilt rotator (163) is the leading position (x) of the rotation axis of the rotation motor (310) in the second tilt-rotate coordinate system, which is a local coordinate system.t3 , y t3 , z t3 ) and the inclination of the axis of rotation (φ r Represents ). Inclination φ of the axis of rotation r θ is an angle related to the design error of the tilt rotator (163) and is obtained by calibration of the tilt rotator (163), etc. The second tilt-rotate coordinate system is X, which extends in the direction in which the joint axis connecting the mounting part (1631) and the tilt part (1632) extends, based on the center position of the joint axis connecting the mounting part (1631) and the tilt part (1632). t2 Z extending in the direction in which the rotation axis of the axis of the rotation motor (310) is extended. t2 Axis, and X t2 Axis and Z t2 Y perpendicular to the axis t2 It is a coordinate system composed of axes.

[0065] The geometric data of the rotating part (1633) of the tilt rotator (163) is the center position (x) of the mounting surface of the bucket (164) in the third tilt rotate coordinate system, which is a local coordinate system. t4 , y t4 , z t4 ) represents. The third tilt-rotate coordinate system is Z, which extends in the direction in which the rotation axis of the rotation motor (310) extends, based on the center position of the mounting surface of the bucket (164). t3 X perpendicular to the axis and the axis of rotation t3 Axis and Y t3 It is a coordinate system composed of axes. And, the bucket (164) has a blade tip at Y t3 It is mounted on the rotating part (1633) so as to be parallel to the axis.

[0066] The geometric data of the bucket (164) is the position (x) of a plurality of contour points of the bucket (164) in the third tilt-rotate coordinate system. bk , y bk , z bkIt represents ). Examples of contour points include the ends and center of the blade tip of the bucket (164), the ends and center of the bottom portion of the bucket (164), and the ends and center of the back portion (heel portion) of the bucket (164).

[0067] The position attitude calculation unit (215) calculates the boom angle θ acquired by the measurement value acquisition unit (214). bm Based on the measured values ​​and the geometric data of the slewing body (140), a boom-to-body transformation matrix T for transforming from the boom coordinate system to the body coordinate system by the following equation (1). bm sb Generates the boom-body transformation matrix T. bm sb is, Y bm Boom angle θ around the axis bm Rotate by that amount, and also the deviation between the origin of the body coordinate system and the origin of the boom coordinate system (x bm , y bm , z bm It is a matrix that translates by )

[0068] [Number 1]

[0069]

[0070] The position attitude calculation unit (215) calculates the angle θ acquired by the measurement value acquisition unit (214). am Based on the measured values ​​and the geometric data of the boom (161), an arm-boom transformation matrix T for transforming from the arm coordinate system to the boom coordinate system by the following equation (2). am bm Generates the arm-boom transform matrix T am bm silver, Y am rock angle θ around the axis am Rotate by that amount, and also the deviation between the origin of the boom coordinate system and the origin of the arm coordinate system (x am , y am , z am It is a matrix that translates by ). In addition, the position attitude calculation unit (215) is a boom-body transformation matrix T bm sband the arm-boom transform matrix T am bm By calculating the product of, the arm-to-body transformation matrix T for transforming from the arm coordinate system to the body coordinate system am sb Creates.

[0071] [Number 2]

[0072]

[0073] The position attitude calculation unit (215) calculates the bucket angle θ acquired by the measurement value acquisition unit (214). bk Based on the measured value of and the geometric data of the arm (162), a first tilt-arm transformation matrix T for transforming from the first tilt-rotate coordinate system to the arm coordinate system by the following equation (3). t1 am Generates the first tilt-arm transform matrix T t1 am is Y t1 Bucket angle θ around the axis bk Rotate by that amount, and also the deviation (x) between the origin of the arm coordinate system and the origin of the first tilt-rotate coordinate system t1 , y t1 , z t1 ) translated parallel by ), and the inclination φ of the joint axis of the tilt part (1632) t It is a matrix that causes it to tilt by that much more. In addition, the position attitude calculation unit (215) is an arm-body transformation matrix T am sb and the first tilt-arm transform matrix T t1 am By calculating the product of, the first tilt-body transformation matrix T for transforming from the first tilt-rotate coordinate system to the body coordinate system t1 sb Creates.

[0074] [Number 3]

[0075]

[0076] The position attitude calculation unit (215) calculates the tilt angle θ acquired by the measurement value acquisition unit (214). tBased on the measured value and the geometric data of the tilt rotator (163), a second tilt-to-first tilt transformation matrix T for transforming from the first tilt-rotate coordinate system to the second tilt-rotate coordinate system by the following equation (4). t2 t1 Generates the second tilt-first tilt transform matrix T. t2 t1 Eun, X t2 Tilt angle θ around the axis t Rotate by that amount, and also the deviation (x) between the origin of the first tilt-rotate coordinate system and the origin of the second tilt-rotate coordinate system t2 , y t2 , z t2 ) translated parallel by ), and the inclination φ of the rotation axis of the rotating part (1633) r It is a matrix that causes it to tilt by that amount more. In addition, the position attitude calculation unit (215) is the first tilt-body conversion matrix T t1 sb and the second tilt-first tilt transform matrix T t2 t1 By calculating the product of, the second tilt-body transformation matrix T for transforming from the second tilt-rotate coordinate system to the body coordinate system t2 sb Creates.

[0077] [Number 4]

[0078]

[0079] The position attitude calculation unit (215) calculates the rotation angle θ acquired by the measurement value acquisition unit (214). r Based on the measured value and the geometric data of the tilt rotator (163), a third tilt-to-second tilt transformation matrix T for transforming from the second tilt-rotate coordinate system to the third tilt-rotate coordinate system by the following equation (5). t3 t2 Generates the third tilt-second tilt transform matrix T t3 t2 is Z t3 Rotation angle θ around the axis rRotate by that amount, and also the deviation (x) between the origin of the second tilt-rotate coordinate system and the origin of the third tilt-rotate coordinate system t3 , y t3 , z t3 It is a matrix that translates by ). In addition, the position attitude calculation unit (215) is a second tilt-body transformation matrix T t2 sb and the third tilt-second tilt transform matrix T t3 t2 By calculating the product of, the third tilt-body transformation matrix T for transforming from the third tilt-rotate coordinate system to the body coordinate system t3 sb Creates.

[0080] [Number 5]

[0081]

[0082] The position position calculation unit (215) is the center position (x) of the mounting surface of the bucket (164). t4 , y t4 , z t4 The positions of multiple contour points (x) in the third tilt-rotate coordinate system represented by the geometric data of the ) and the bucket (164) bk , y bk , z bk The sum of ) and the third tilt-body transformation matrix T bk sb By calculating the product of the two, the positions of multiple contour points of the bucket (164) in the vehicle body coordinate system can be obtained.

[0083] However, the angle of the blade tip of the bucket (164) with respect to the ground surface of the working machine (100), that is, the X of the vehicle body coordinate system sb -Y sb The plane and the Y of the third tilt-rotate coordinate system t3 The angle formed by the axes is the boom angle θ bm , rock angle θ am , bucket angle θ bk , tilt angle θ t and rotate angle θ rIt is determined by. Thus, the position attitude calculation unit (215) specifies a bucket coordinate system with the center position of the mounting surface of the bucket (164) at the base of the bucket (164), that is, at the tilt rotator (163), as the starting point, as shown in FIG. 1. The bucket coordinate system is X extending in the direction in which the blade tip of the bucket (164) is facing bk Axis, X bk Y that is perpendicular to the axis and also extends along the edge of the bucket (164) bk Axis, and X bk Axis and Y bk Z perpendicular to the axis bk It is an orthogonal coordinate system composed of axes. Hereinafter, X bk The axis is the bucket tilt axis, Y bk The axis is the bucket pitch axis, Z bk The axis is also called the bucket rotation axis. Bucket tilt axis X bk , bucket pitch axis Y bk and bucket rotation axis Z bk is a virtual axis and is different from the joint axis of the tilt rotator (163). And, when the tilt of the rotation axis of the rotation motor (310) is zero, the bucket coordinate system and the third tilt rotator coordinate system coincide.

[0084] The position attitude calculation unit (215), based on the geometric data of the tilt rotator (163), uses a bucket-to-third tilt transformation matrix T for transforming from the third tilt rotate coordinate system to the bucket coordinate system by the following equation (6). bk t3 Generates the bucket-third tilt transform matrix T. bk t3 is Y t3 Inclination φ of the axis of rotation around the axis r It is a matrix that rotates by that amount.

[0085] [Number 6]

[0086]

[0087] Method of controlling the work machine (100)

[0088] Hereinafter, a control method for a work machine (100) related to the first embodiment will be described. FIGS. 5 and 6 are flowcharts showing intervention control of a work machine (100) in the first embodiment. When an operator of the work machine (100) starts operating the work machine (100), the control device (200) executes the control shown below at a predetermined control cycle (e.g., 1000 milliseconds).

[0089] The measurement value acquisition unit (214) acquires measurement values ​​of the inclination measuring instrument (401), position orientation measuring instrument (402), boom angle sensor (403), rock angle sensor (404), bucket angle sensor (405), tilt angle sensor (406) and rotation angle sensor (407) (step S101).

[0090] The position attitude calculation unit (215) calculates the positions of a plurality of contour points of the bucket (164) in the vehicle body standard system based on the measurement values ​​obtained in step S101 (step S102). In addition, the position attitude calculation unit (215) calculates the attitude of the bucket in the vehicle body coordinate system based on the measurement values ​​obtained in step S101 (step S103). The attitude of the bucket in the vehicle body coordinate system is each axis (X) of the bucket coordinate system in the vehicle body coordinate system. bk , Y bk , Z bk The attitude matrix R representing the direction of ) cur It is indicated by. Attitude matrix R indicating the attitude of the bucket (164). cur All translation components of are set to zero.

[0091] Next, the intervention determination unit (216) converts the position of the design plane displayed in the global coordinate system to the position of the vehicle body coordinate system by rotating and translating the design plane data recorded in the storage (250) based on the measurement values ​​of the inclination measuring instrument (401) and the position orientation measuring instrument (402) acquired in step S101 (step S104). The intervention determination unit (216) identifies the one closest to the design plane among the multiple contour points of the bucket (164) as the control point based on the positions of the multiple contour points of the bucket (164) calculated in step S102 and the position of the design plane in the vehicle body coordinate system converted in step S104 (step S105). The intervention determination unit (216) identifies the design plane (polygon) located vertically below the control point identified in step S105 in the design plane data (step S106). The intervention determination unit (216) identifies the X of the bucket coordinate system passing through the control point. bk -Z bk A first design line is calculated as the intersection line of a plane parallel to the plane and a specific design plane in step S106 (step S107). Additionally, the intervention determination unit (216) calculates the Y of the bucket coordinate system passing through the control point. bk -Z bk Calculate a second design line that is the intersection line of a plane parallel to the plane and the design plane (Step S108).

[0092] Next, the intervention determination unit (216) determines whether the distance between the control point and the first design line is less than or equal to the intervention threshold (step S109). If the distance between the control point and the first design line is less than or equal to the intervention threshold (step S109: YES), the intervention determination unit (216) determines whether an operation other than the boom (161) has been received based on the operation signal from the operation device (271) acquired by the operation signal acquisition unit (211) (step S110). When the intervention judgment unit (216) determines that it has received only the operation of the boom (161), or determines that it has not received the operation (Step S110: NO), it is presumed that the operator has the intention to approach the design surface with the cutting edge of the bucket (164), so the intervention control unit (217) generates control signals for the bucket cylinder (308), tilt cylinder (309), and rotary motor (310) by performing the cutting edge alignment control described later (Step S111).

[0093] Meanwhile, if the intervention determination unit (216) determines that it has received an operation other than the boom (161) (Step S110: YES), the intervention determination unit (216) determines whether it has received an operation other than the slewing motor (305) and the arm (162) based on the operation signal from the operation device (271) acquired by the operation signal acquisition unit (211) (Step S112). If the intervention determination unit (216) determines that it has not received an operation other than the slewing motor (305) and the arm (162) (Step S112: NO), it is presumed that the operator intends to excavate the construction site along the design plane, so the intervention control unit (217) generates control signals for the bucket cylinder (308), tilt cylinder (309), and rotation motor (310) by performing the design plane tracking control described later (Step S113).

[0094] When the distance between the control point and the first design line is less than or equal to the intervention threshold, the intervention control unit (217) specifies the limiting speed of the blade tip of the bucket (164) based on the distance between the control point and the first design line and a predetermined limiting speed table (step S114). The limiting speed table is a function representing the relationship between the distance between the blade tip and the design line and the limiting speed of the blade tip, wherein the limiting speed decreases as the distance decreases. The intervention control unit (217) determines whether the speed of the blade tip exceeds the limiting speed specified in step S114 (step S115). If the speed of the blade tip exceeds the limiting speed (step S115: YES), the intervention control unit (217) calculates the speed of the boom (161) to match the speed of the blade tip to the limiting speed and generates a control signal for the boom cylinder (306) (step S116). If the speed of the blade tip does not exceed the limit speed (Step S115: NO), the intervention control unit (217) does not perform intervention control for the boom cylinder (306).

[0095] Then, the control signal output unit (218) generates a control signal according to the amount of operation indicated by the operation signal from the operation device (271) acquired by the operation signal acquisition unit (211) for an actuator that does not have a control signal generated by the intervention control unit (217), and outputs the control signal of each actuator to the control valve (303) (step S117).

[0096] Edge-aligned control

[0097] FIG. 7 is a flowchart showing the edge alignment control in the first embodiment.

[0098] The edge alignment control is a control that brings the edge of the bucket (164) and the design plane close together in parallel. Specifically, the edge alignment control is a bucket tilt axis X that extends in the direction in which the edge of the bucket (164) is facing. bk Determine as the virtual axis of rotation, and the bucket tilt axis X bk The bucket pitch axis Y, which is orthogonal to and also extends along the cutting edge of the bucket (164).bk It is a control that operates at least one of the bucket cylinder (308), tilt cylinder (309), and rotary motor (310) so that the design plane and the bucket tilt axis are in close proximity to each other. In the cutting edge alignment control, the bucket tilt axis X bk The bucket (164) is rotated around. Therefore, the intervention control unit (217) is the bucket pitch axis Y of the bucket coordinate system. bk Angle of the periphery and bucket rotation axis Z bk Target value θ of the bucket angle for bringing the tip of the bucket (164) and the second design line close to parallel while maintaining the surrounding angle bk_tgt , target value of tilt angle θ t_tgt and target value θ of the rotation angle r_tgt is calculated. Specifically, the intervention control unit (217) calculates the bucket angle θ in the following order. bk , tilt angle θ t and the rotation angle θ r Calculate the target value of.

[0099] The intervention control unit (217) is the bucket pitch axis Y of the bucket coordinate system. bk Based on the angle formed by the second design line obtained in step S108 and the predetermined bucket tilt table, the bucket tilt axis X bk Target value θ of the surrounding angular velocity bk_t_tgt Determine (Step S301). Target value of angular velocity θ bk_t_tgt It is expressed as the angle of rotation per unit time. For a bucket tilt table, the bucket pitch axis Y bk The angle formed by the design line and the bucket tilt axis X bk It is a function representing the relationship of surrounding angular velocity, wherein the angular velocity decreases as the angle becomes smaller. The intervention control unit (217) [is] the target value θ of the angular velocity according to the following equation (7). bk_t_tgt The rotation matrix R of the bucket coordinate system representing bk_t bk Write (Step S302).

[0100] [Number 7]

[0101]

[0102] The intervention control unit (217) is a matrix R that indicates the current attitude of the bucket (164) calculated in step S103. cur rotation matrix R bk_t bk By multiplying, the target posture R of the bucket (164) after a unit of time tgt Calculate (step S303). The intervention control unit (217) calculates the current posture R of the bucket (164). cur Target posture R of the bucket (164) after a unit of time tgt Based on this, the bucket angle θ by equations (8)-(10) bk , tilt angle θ t and rotation angle θ r Calculate the target value of (Step S304).

[0103] [Number 8]

[0104]

[0105] [Number 9]

[0106]

[0107] [Number 10]

[0108]

[0109] According to equations (8)-(10), the intervention control unit (217) is the current position R of the bucket (164). cur Target posture R of the bucket (164) tgt Angular velocity θ to cancel out the difference bk_tgt , θ t_tgt , θ r_tgt The intervention control unit (217) generates control signals for the bucket cylinder (308), tilt cylinder (309), and rotation motor (310) based on the target value of the angular velocity obtained in step S304 (step S305).

[0110] Design Plane Following Control

[0111] FIG. 8 is a flowchart showing design plane tracking control in the first embodiment.

[0112] Design plane following control is a control that causes the cutting edge of the bucket (164) to follow the design plane during excavation or ground leveling operations. Specifically, the design plane following control is a bucket tilt axis X that extends in the direction in which the cutting edge of the bucket (164) is facing. bk Determine as the virtual axis of rotation, and the bucket tilt axis X in the global coordinate system. bk While maintaining the axis direction, bucket tilt axis X bk The bucket pitch axis Y, which is orthogonal to and also extends along the cutting edge of the bucket (164). bk It is a control that operates at least one of the bucket cylinder (308), tilt cylinder (309), and rotary motor (310) so that the design plane is parallel and closely aligned. In the design plane tracking control, the bucket tilt axis X in the global coordinate system bk While maintaining the axis direction, bucket tilt axis X bk The bucket (164) is rotated around. Therefore, the intervention control unit (217) cancels the change in the opening direction relative to the global coordinate system caused by the operation of the work machine (100) by the operator, while the bucket tilt axis X bk Target value θ of the bucket angle for bringing the blade tip of the bucket (164) and the second design line close to parallel by rotation around it. bk_tgt , target value of tilt angle θ t_tgt and target value θ of the rotation angle r_tgt is calculated. Specifically, the intervention control unit (217) calculates the bucket angle θ in the following order. bk , tilt angle θ t and the rotation angle θ r Calculate the target value of.

[0113] The intervention control unit (217) rotates the matrix indicating the current attitude of the bucket (164) calculated in step S103 based on the amount of operation of the pivot motor (305) and arm cylinder (307) acquired by the operation signal acquisition unit (211) and the measurement value of the inclination meter (401) acquired by the measurement value acquisition unit (214), thereby forming an attitude matrix R that indicates the attitude of the bucket (164) after a unit time (control cycle).man Calculate (Step S401).

[0114] Next, the intervention control unit (217) is the bucket pitch axis Y of the bucket coordinate system. bk Based on the angle formed by the second design line obtained in step S108 and the predetermined bucket tilt table, the bucket tilt axis X bk Target value θ of the surrounding angular velocity bk_t_tgt is determined (step S402). The intervention control unit (217) determines the target value θ of the angular velocity according to Equation (7). bk_t_tgt The rotation matrix R of the bucket coordinate system representing bk_t bk Write (Step S403).

[0115] The intervention control unit (217) has a posture matrix R that indicates the posture of the bucket (164) after a unit time (control cycle) calculated in step S401. man rotation matrix R bk_t bk By multiplying, the target posture R of the bucket (164) after a unit of time tgt Calculate (step S404). The intervention control unit (217) calculates the attitude matrix R man and target posture R tgt Based on this, the bucket angle θ by equations (11)-(13) bk , tilt angle θ t and rotation angle θ r Calculate the target value of (Step S405).

[0116] [Number 11]

[0117]

[0118] [Number 12]

[0119]

[0120] [Number 13]

[0121]

[0122] According to equations (11)-(13), the intervention control unit (217) is the current position R of the bucket (164). curTarget posture R of the bucket (164) tgt Angular velocity θ to cancel out the difference bk_tgt , θ t_tgt , θ r_tgt The intervention control unit (217) generates control signals for the bucket cylinder (308), tilt cylinder (309), and rotation motor (310) based on the target value of the angular velocity obtained in step S405 (step S406).

[0123] Actions and Effects

[0124] According to the first embodiment, when an operator operates the boom cylinder (306) to bring the bucket (164) close to the design surface, the control device (200) controls the tilt rotator (163) so that the blade tip of the bucket (164) becomes parallel to the design surface. At this time, the control device (200) controls the tilt rotator (163) to rotate around the bucket tilt axis in the bucket coordinate system so that the direction in which the blade tip of the bucket (164) faces does not change. By doing so, the control device (200) can align the blade tip to the design surface while reflecting the will of the operator. After that, when the operator excavates the target with the working machine (100) by operating the arm cylinder (307) and the slewing motor (305) while the cutting edge of the bucket (164) is in contact with the target, the control device (200) controls the tilt rotator (163) so that the cutting edge of the bucket (164) follows the design plane. At this time, the control device (200) controls the direction in which the cutting edge of the bucket (164) faces so that it does not change when viewed from the global coordinate system, even if the slewing body (140) rotates due to the operator's operation. In this way, the control device (200) can automatically keep the cutting edge facing continuously in the excavation direction.

[0125] In addition, according to the first embodiment, by setting the attitude maintenance mode, the attitude of the bucket (164) as viewed from the global coordinate system can be maintained constant even when the slewing body (140), boom (161), and arm (162) are operated. For example, when excavating a place that is sufficiently higher than the design surface, the attitude of the bucket (164) can be maintained so that the cutting edge can be easily kept directed in the direction of excavation. In addition, for example, when moving a load by attaching an attachment such as a grapple to the working machine (160) instead of the bucket (164), the attitude of the attachment can be maintained so that the load can be prevented from falling due to a change in attitude.

[0126] Additionally, when the control device (200) receives an operation signal for operating the tilt rotator (163), namely an operation signal of any one of the bucket cylinder (308), tilt cylinder (309), and rotary motor (310), the intervention control unit (217) does not generate a control signal for the tilt rotator. The fact that an operation signal for operating the tilt rotator (163) is input by the operator implies that the operator likely has the intention to operate the direction in which the bucket (164) is facing. Therefore, in such a case, the control device (200) does not generate a control signal for the tilt rotator, thereby not interfering with the operator's operation.

[0127] <Other embodiments>

[0128] Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design changes are possible. That is, in other embodiments, the order of the above-described processing may be appropriately changed. In addition, some of the processing may be executed in parallel.

[0129] The control device (200) related to the above-described embodiment may be configured by a single computer, or the configuration of the control device (200) may be distributed among multiple computers and function as a control device (200) by the multiple computers cooperating with each other. In this case, some of the computers constituting the control device (200) may be mounted inside the work machine, and other computers may be installed outside the work machine. For example, in another embodiment, the operating device (271) and the monitor device (272) may be installed remotely from the work machine (100), and the components of the control device (200), excluding the measurement value acquisition unit (214) and the control signal output unit (218), may be installed on a remote server.

[0130] In addition, the work machine (100) related to the above-described embodiment is a hydraulic shovel, but is not limited thereto. For example, the work machine (100) related to another embodiment may be a non-self-propelled work machine fixed to the ground. In addition, the work machine (100) related to another embodiment may be a work machine that does not have a swivel body.

[0131] The work machine (100) related to the above-described embodiment is equipped with a bucket (164) as an attachment to the work machine (160), but is not limited thereto. For example, the work machine (100) related to other embodiments may be equipped with a breaker, fork, grapple, etc., as an attachment. In this case as well, the control device (200) is X extending in the direction in which the blade tip of the attachment is facing, similar to the bucket coordinate system. bk Axes and Y extending in the direction following the edge bk Axis and, X bk Axis and Y bk Z perpendicular to the axis bk The tilt rotator (163) is controlled by a local coordinate system formed by an axis.

[0132] In another embodiment, each axis of the tilt rotator (163) does not need to be orthogonal if it intersects in different planes. Specifically, with respect to axis AX1 related to the joint axis connecting the arm (162) and the mounting part (1631), axis AX2 related to the joint axis connecting the mounting part (1631) and the tilt part (1632), and rotation axis AX3 of the rotation motor (310), when the tilt angle and rotation angle of the tilt rotator (163) are zero, the plane parallel to axis AX1 and axis AX2, the plane parallel to axis AX2 and axis AX3, and the plane parallel to axis AX3 and axis AX1 are each different.

[0133] In addition, the control device (200) related to other embodiments may not have a design plane setting function. Even in this case, the control device (200) can automatically control the tilt rotator (163) by performing bucket posture maintenance control. For example, the operator can perform a simple stop operation without setting the design plane.

[0134] [Industrial Applicability]

[0135] According to the above description, the system can support the operation of a work machine having an attachment supported on a support member through a tilt rotator. Explanation of the symbols

[0136] 100: Working machine, 120: Traveling body, 140: Slewing body, 160: Working implement, 161: Boom, 162: Arm, 163: Tilt rotator, 1631: Mounting part, 1632: Tilt part, 1633: Rotating part, 164: Bucket, 180: Cab, 200: Control unit, 210: Processor, 211: Operation signal acquisition unit, 212: Input unit, 213: Display control unit, 214: Measurement value acquisition unit, 215: Position attitude calculation unit, 216: Intervention determination unit, 217: Intervention control unit, 218: Control signal output unit, 230: Main memory, 250: Storage, 270: Interface, 271: Operating device, 272: Monitor device, 301: Engine, 302: Hydraulic Pump, 303: Control Valve, 304: Travel Motor, 305: Slewing Motor, 306: Boom Cylinder, 307: Arm Cylinder, 308: Bucket Cylinder, 309: Tilt Cylinder, 310: Rotary Motor, 401: Inclination Meter, 402: Position and Orientation Meter, 403: Boom Angle Sensor, 404: Arm Angle Sensor, 405: Bucket Angle Sensor, 406: Tilt Angle Sensor, 407: Rotation Angle Sensor

Claims

Claim 1 A system for controlling a work machine comprising a support member movably supported on a vehicle body, a tilt rotator mounted on the tip of the support member, and an attachment having teeth and rotatably supported around three axes intersecting the support member in different planes through the tilt rotator, the system comprises a processor, wherein the processor acquires measurement values ​​from a plurality of sensors, calculates the attitude of the attachment relative to the vehicle body based on the measurement values, determines a virtual axis of rotation that is different from the joint axis of the tilt rotator and extends in the direction in which the teeth of the attachment face, based on the calculated attitude of the attachment, acquires an operation signal for operating the support member from an operating device, maintains the axial direction of the virtual axis of rotation in a global coordinate system based on the calculated attitude of the attachment and the amount of operation indicated by the operation signal for operating the support member, and also, a design plane and the attachment A system for generating a control signal for the tilt rotator to rotate the attachment around the virtual axis of rotation so that the cutting edge is in close proximity to the parallel, and outputting the generated control signal. Claim 2 A system according to claim 1, wherein the working machine comprises a base that pivotably supports the vehicle body, and the processor acquires a control signal for pivoting the vehicle body relative to the base from the operating device, and based on the calculated attitude of the attachment and the amount of operation indicated by the control signal for pivoting the vehicle body, maintains the axial direction of the virtual rotation axis in a global coordinate system and also generates a control signal for the tilt rotator for rotating the attachment around the virtual rotation axis so that the design plane and the cutting edge of the attachment are in close proximity to each other. Claim 3 A system according to claim 1 or 2, wherein the virtual rotation axis is an axis extending in the direction toward which the cutting edge of the attachment faces. Claim 4 A system according to claim 1 or 2, wherein the processor outputs a control signal of the tilt rotator when the distance between the design plane and the cutting edge of the attachment is less than or equal to an intervention threshold. Claim 5 A system according to claim 1 or 2, wherein the processor, when an operation signal for operating the tilt rotator is input from the operating device, does not output a control signal of the generated tilt rotator but outputs a control signal based on the input operation signal. Claim 6 A method for controlling a work machine comprising a support member movably supported on a vehicle body, a tilt rotator supported at the tip of the support member, and an attachment having a cutting edge and rotatably supported around three axes intersecting the support member in different planes through the tilt rotator, the method comprising: acquiring measurement values ​​from a plurality of sensors; calculating the attitude of the attachment relative to the vehicle body based on the measurement values; determining a virtual axis of rotation based on the calculated attitude of the attachment, which is different from the joint axis of the tilt rotator and extends in the direction toward which the cutting edge of the attachment faces; acquiring an operation signal for operating the work machine from an operating device; and, based on the calculated attitude of the attachment and the amount of operation indicated by the operation signal for operating the support member, maintaining the axial direction of the virtual axis of rotation in a global coordinate system and also positioning the attachment around the virtual axis of rotation so that the design plane and the cutting edge of the attachment are in close parallel. A method comprising: a step of generating a control signal for the tilt rotator to rotate; and a step of controlling the tilt rotator according to the generated control signal. Claim 7 delete

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