System, method, and storage medium for controlling a work machine

Abstract

A measurement value acquisition section acquires measurement values from a plurality of sensors. A position and posture calculation section calculates a current posture of a work tool based on the measurement values. A target posture decision section decides an imaginary rotation axis based on the calculated current posture of the work tool in a case where a prescribed control start condition is satisfied. A rotation amount calculation section generates a control signal of a tilt rotator for rotating the work tool around the imaginary rotation axis by a prescribed amount in a manner that the current posture becomes a target posture. A control signal output section outputs the generated control signal.

Description

Technical Field

[0001] This disclosure relates to systems, methods, and procedures for controlling operating machinery.

[0002] This application claims priority to Japan Patent Application No. 2021-161174, filed on September 30, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] Patent Document 1 discloses a control system for a construction machine (operating machine) equipped with a tilting bucket capable of tilting and rotating. Thus, it is known that operating machines are equipped with multiple rotating mechanisms capable of rotating about mutually different axes and capable of rotating working tools such as buckets as desired.

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-125599 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, tilting rotators are known to support the components of a work machine in a way that allows them to rotate around three mutually orthogonal axes. By installing a tilting rotator on the work machine, the components can be oriented in any direction. On the other hand, in work machines such as hydraulic excavators, when loading soil or other materials into the loading platform of a dump truck, there is a requirement to minimize soil spillage during the movement of the bucket onto the loading platform. However, in hydraulic excavators like the one described above, which are equipped with multiple rotating mechanisms, if the bucket is moved without being horizontal in the width direction (along the direction of the bucket tip), the soil loaded into the bucket is prone to spilling out midway through transport to the loading platform of the dump truck. Therefore, it is preferable to adjust the width direction of the bucket to be horizontal when moving the bucket.

[0009] On the other hand, in hydraulic excavators equipped with tilt-rotor mechanisms, it is envisioned that the bucket opening direction is aligned with the digging face using this rotating mechanism. Therefore, considering the efficiency of the digging operation, there is a requirement to avoid changing the bucket opening direction before and after the loading operation of the dump truck.

[0010] The purpose of this disclosure is to provide a system, method, and procedure for simplifying the operation of aligning a second reference direction (e.g., the direction of the bucket tip) with a predetermined surface (e.g., a vehicle body reference surface) in a working machine having a working tool supported on a working device via a tilting rotator, without changing the first reference direction of the working tool (e.g., the opening direction of the bucket).

[0011] Methods for solving problems

[0012] According to one aspect of this disclosure, a system for controlling a working machine includes: a working device supported on a vehicle body in an actuating manner; a tilting rotator mounted at the front end of the working device; and a working tool supported on the working device via the tilting rotator in a manner capable of rotating about three axes intersecting in mutually different planes. The system for controlling the working machine includes a processor. In the processor, measurement values ​​are acquired from multiple sensors. In the processor, the current posture of the working tool is calculated based on the measurement values. In the processor, under predetermined control start conditions, an imaginary rotation axis is determined based on the calculated current posture of the working tool. In the processor, a control signal is generated for rotating the tilting rotator by a predetermined amount about the imaginary rotation axis in a manner that causes the working tool to rotate from its current posture to a target posture. In the processor, the generated control signal is output.

[0013] Invention Effects

[0014] According to the above scheme, in a working machine having a working tool supported on a working device via a tilting rotator, the operation of aligning the second reference direction with a specified surface can be simplified without changing the first reference direction of the working tool. Attached Figure Description

[0015] Figure 1 This is a schematic diagram showing the structure of the work machine 100 according to the first embodiment.

[0016] Figure 2 This is a diagram showing the structure of the tilting rotator 163 according to the first embodiment.

[0017] Figure 3 This is a diagram showing the drive system of the work machine 100 according to the first embodiment.

[0018] Figure 4 This is a schematic block diagram showing the structure of the control device 200 according to the first embodiment.

[0019] Figure 5 This is a flowchart illustrating the angle alignment function in the first embodiment.

[0020] Figure 6 This is a diagram showing the details of the operating device in the first embodiment.

[0021] Figure 7 This is a diagram illustrating the effect of the angle alignment function in the first embodiment.

[0022] Figure 8 This is a diagram illustrating the effect of the angle alignment function in the first embodiment. Detailed Implementation

[0023] <First Implementation Method>

[0024] Structure of Operating Machinery

[0025] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings.

[0026] Figure 1 This is a schematic diagram showing the structure of the work machine 100 according to the first embodiment. The work machine 100 of the first embodiment is, for example, a hydraulic excavator. The work machine 100 includes a traveling body 120, a rotating body 140, a working device 160, a cab 180, and a control device 200. The work machine 100 of the first embodiment is controlled in such a way that the tip of the bucket 164 does not cross the design surface.

[0027] The traveling body 120 supports the working machine 100 so that it can move. The traveling body 120 is, for example, a pair of tracks on the left and right sides.

[0028] The rotating body 140 is supported on the traveling body 120 in a manner that allows it to rotate around the center of rotation.

[0029] The working device 160 is supported on the rotating body 140 in an operable manner. The working device 160 is hydraulically driven. The working device 160 includes a boom 161, a stick 162, a tilt rotator 163, and a bucket 164 as a working tool. The base end of the boom 161 is rotatably mounted on the rotating body 140. The base end of the stick 162 is rotatably mounted on the front end of the boom 161. The tilt rotator 163 is rotatably mounted on the front end of the stick 162. The bucket 164 is mounted on the tilt rotator 163. The bucket 164 is supported on the working device 160 via the tilt rotator 163 in a manner that allows it to rotate about three axes intersecting in different planes. Here, the portion of the rotating body 140 in which the working device 160 is mounted is referred to as the front portion. Furthermore, regarding the rotating body 140, based on the front portion, the portion on the opposite side is referred to as the rear portion, the portion on the left is referred to as the left portion, and the portion on the right is referred to as the right portion.

[0030] Figure 2This diagram illustrates the structure of the tilting rotator 163 according to the first embodiment. The tilting rotator 163 is mounted on the front end of the stick 162 to support the bucket 164. The tilting rotator 163 includes a mounting portion 1631, a tilting portion 1632, and a rotating portion 1633. The mounting portion 1631 is mounted on the front end of the stick 162 in a manner rotatable about an axis extending in the left-right direction as shown in the diagram. The tilting portion 1632 is mounted on the mounting portion 1631 in a manner rotatable about an axis extending in the front-back direction as shown in the diagram. The rotating portion 1633 is mounted on the tilting portion 1632 in a manner rotatable about an axis extending in the up-down direction as shown in the diagram. Ideally, the rotation axes of the mounting portion 1631, the tilting portion 1632, and the rotating portion 1633 are orthogonal to each other. The base end of the bucket 164 is fixed to the rotating portion 1633. Thus, the bucket 164 can rotate relative to the stick 162 about three orthogonal axes. However, in reality, the rotation axes of the mounting part 1631, tilting part 1632, and rotating part 1633 contain design errors and may not be orthogonal.

[0031] The operator's cab 180 is located at the front of the swing body 140. Inside the operator's cab 180 are an operating device 271 for the operator to operate the machinery 100, and a monitor device 272 serving as a human-machine interface for the control device 200. The operating device 271 receives inputs from the operator regarding the operation of the travel motor 304, the swing motor 305, the boom cylinder 306, the stick cylinder 307, the bucket cylinder 308, the tilt cylinder 309, and the swivel motor 310. The monitor device 272 receives inputs from the operator regarding the setting and deactivation of the bucket posture holding mode. The bucket posture holding mode refers to the mode in which the control device 200 controls the bucket cylinder 308, the tilt cylinder 309, and the swivel motor 310 to automatically maintain the posture 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.

[0032] The control device 200 controls the traveling body 120, the rotating body 140, and the working device 160 based on the operator's operation of the operating device 271. The control device 200 is, for example, located inside the cab 180.

[0033] Drive System of Operation Machinery 100

[0034] Figure 3 This is a diagram showing the drive system of the work machine 100 according to the first embodiment.

[0035] The work machinery 100 includes multiple actuators for driving the work machinery 100. Specifically, the work machinery 100 includes an engine 301, a hydraulic pump 302, a control valve 303, a pair of travel motors 304, a swing motor 305, a boom cylinder 306, a stick cylinder 307, a bucket cylinder 308, a tilt cylinder 309, and a rotary motor 310.

[0036] Engine 301 is the prime mover that drives hydraulic pump 302.

[0037] The hydraulic pump 302 is driven by the engine 301 and supplies working oil to the travel motor 304, swing motor 305, boom cylinder 306, stick cylinder 307 and bucket cylinder 308 via the control valve 303.

[0038] Control valve 303 controls the flow rate of working oil supplied from hydraulic pump 302 to travel motor 304, swing motor 305, boom cylinder 306, stick cylinder 307 and bucket cylinder 308.

[0039] The travel motor 304 is driven by working oil supplied from the hydraulic pump 302, which drives the travel body 120.

[0040] The rotary motor 305 is driven by working oil supplied from the hydraulic pump 302, causing the rotary body 140 to rotate relative to the traveling body 120.

[0041] Boom cylinder 306 is a hydraulic cylinder used to drive boom 161. The base end of boom cylinder 306 is mounted on slewing body 140. The front end of boom cylinder 306 is mounted on boom 161.

[0042] The boom cylinder 307 is a hydraulic cylinder used to drive the boom 162. The base end of the boom cylinder 307 is mounted on the boom 161. The front end of the boom cylinder 307 is mounted on the boom 162.

[0043] Bucket cylinder 308 is a hydraulic cylinder used to drive tilt rotator 163 and bucket 164. The base end of bucket cylinder 308 is mounted to stick 162. The front end of bucket cylinder 308 is mounted to tilt rotator 163 via a connecting rod member.

[0044] The tilting cylinder 309 is a hydraulic cylinder used to drive the tilting unit 1632. The base end of the tilting cylinder 309 is mounted on the mounting part 1631. The front end of the rod of the tilting cylinder 309 is mounted on the tilting unit 1632.

[0045] The rotary motor 310 is a hydraulic motor used to drive the rotating part 1633. The bracket and stator of the rotary motor 310 are fixed to the tilting part 1632. The rotating shaft and rotor of the rotary motor 310 are arranged to extend in the vertical direction shown in the figure and are fixed to the rotating part 1633.

[0046] Measurement System for Operational Machinery 100

[0047] The machine tool 100 is equipped with multiple sensors for measuring the posture, orientation, and position of the machine tool 100. Specifically, the machine tool 100 is equipped with a tilt meter 401, a position and orientation meter 402, a boom angle sensor 403, a stick angle sensor 404, a bucket angle sensor 405, a tilt angle sensor 406, and a rotation angle sensor 407.

[0048] Inclinometer 401 measures the attitude of the rotating body 140. Inclinometer 401 measures the tilt angle (e.g., roll, pitch, and yaw) of the rotating body 140 relative to the horizontal plane. An example of inclinometer 401 is an IMU (Inertial Measurement Unit). In this case, inclinometer 401 measures the acceleration and angular velocity of the rotating body 140 and calculates the tilt angle relative to the horizontal plane based on the measurement results. Inclinometer 401 is, for example, located below the cab 180. Inclinometer 401 outputs the attitude data of the rotating body 140 as measured values ​​to control device 200.

[0049] The position and orientation measuring device 402 measures the position of a representative point on the rotating body 140 and the azimuth of the rotating body 140 via GNSS (Global Navigation Satellite System). The position and orientation measuring device 402, for example, includes two GNSS antennas (not shown) mounted on the rotating body 140, and measures the azimuth orthogonal to the line connecting the positions of the two antennas as the azimuth of the working machine 100. The position and orientation measuring device 402 outputs the measured position and azimuth data of the rotating body 140 to the control device 200.

[0050] The boom angle sensor 403 measures the angle of the boom 161 relative to the slewing body 140, i.e., the boom angle. The boom angle sensor 403 can be an IMU mounted on the boom 161. In this case, the boom angle sensor 403 measures the boom angle based on the tilt of the boom 161 relative to the horizontal plane and the tilt of the slewing body measured by the tilt meter 401. The measured value of the boom angle sensor 403 is zero, for example, when the direction of the straight line passing through the base and tip of the boom 161 is consistent with the forward / backward direction of the slewing body 140. It should be noted that in other embodiments, the boom angle sensor 403 can also be a stroke sensor mounted on the boom cylinder 306. Additionally, in other embodiments, the boom angle sensor 403 can also be a rotation sensor provided on the joint axis that rotatably connects the slewing body 140 and the boom 161. The boom angle sensor 403 outputs the measured boom angle data to the control device 200.

[0051] The stick angle sensor 404 measures the angle between the stick 162 and the boom 161, i.e., the stick angle. The stick angle sensor 404 can be an IMU mounted on the stick 162. In this case, the stick angle sensor 404 measures the stick angle based on the inclination of the stick 162 relative to the horizontal plane and the boom angle measured by the boom angle sensor 403. The measured value of the stick angle sensor 404 is zero, for example, when the direction of the straight line passing through the base and tip of the stick 162 coincides with the direction of the straight line passing through the base and tip of the boom 161. It should be noted that in other embodiments, the stick angle sensor 404 can also use a stroke sensor mounted on the stick cylinder 307 to calculate the angle. Additionally, in other embodiments, the stick angle sensor 404 can also be a rotation sensor installed on the joint shaft that rotatably connects the boom 161 and the stick 162. The stick angle sensor 404 outputs the measured stick angle data to the control device 200.

[0052] The bucket angle sensor 405 measures the angle, i.e., the bucket angle, relative to the tilt rotator 163 and the stick 162. The bucket angle sensor 405 can 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 of the bucket cylinder 308. The measured value of the bucket angle sensor 405 is zero, for example, when the direction of the straight line passing through the base end and tip of the bucket 164 coincides with the direction of the straight line passing through the base end and tip of the stick 162. It should be noted that in other embodiments, the bucket angle sensor 405 can also be a rotation sensor installed on the joint shaft that rotatably connects the stick 162 and the mounting portion 1631 of the tilt rotator 163. Additionally, in other embodiments, the bucket angle sensor 405 can also be an IMU installed on the bucket 164. The bucket angle sensor 405 outputs the measured bucket angle data to the control device 200.

[0053] The tilt angle sensor 406 measures the angle, i.e., the tilt angle, relative to the mounting portion 1631 of the tilting rotator 163. The tilt angle sensor 406 can be a rotation sensor installed on a joint shaft that rotatably connects the mounting portion 1631 and the tilting portion 1632. The measured value of the tilt angle sensor 406 is zero, for example, when the rotation axis of the boom 162 is orthogonal to the rotation axis of the rotating portion 1633. It should be noted that in other embodiments, the tilt angle sensor 406 may also use a stroke sensor mounted on the tilting cylinder 309 to calculate the angle. The tilt angle sensor 406 outputs the measured tilt angle data to the control device 200.

[0054] Rotation angle sensor 407 measures the angle, i.e., the rotation angle, between the rotating part 1633 and the tilting part 1632 of the tilting rotator 163. Rotation angle sensor 407 can be a rotation sensor installed on the rotary motor 310. The measured value of tilt angle sensor 406 is zero, for example, when the tip direction of bucket 164 is orthogonal to the operating plane of working device 160. Rotation angle sensor 407 outputs the measured rotation angle data to control device 200.

[0055] Structure of Control Device 200

[0056] Figure 4 This is a schematic block diagram showing the structure of the control device 200 according to the first embodiment.

[0057] The control device 200 is a computer equipped with a processor 210, a main memory 230, a storage device 250, and an interface 270. The control device 200 is an example of a control system. The control device 200 receives measurement values ​​from a tilt meter 401, a position and orientation meter 402, a boom angle sensor 403, a stick angle sensor 404, a bucket angle sensor 405, a tilt angle sensor 406, and a rotation angle sensor 407.

[0058] Storage 250 is a non-transitory tangible storage medium. Examples of storage 250 include magnetic disks, optical disks, optical discs, semiconductor memories, etc. Storage 250 can be an internal medium directly connected to the bus of control device 200, or an external medium connected to control device 200 via interface 270 or a communication line. Operating device 271 and monitoring device 272 are connected to processor 210 via interface 270.

[0059] The memory 250 stores a control program for controlling the machine 100. The control program can also be used to implement a portion of the functions that enable the control device 200 to perform. For example, the control program may function by combining with other programs already stored in the memory 250, or with other programs installed on other devices. It should be noted that in other embodiments, the control device 200 may also include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device), in addition to or replacing the above-described structure. 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 implemented by a processor can also be implemented by this integrated circuit.

[0060] The storage device 250 records geometric data representing the dimensions and center of gravity positions of the rotating body 140, boom 161, stick 162, and bucket 164. Geometric data represents the position of objects within a defined coordinate system. Additionally, the storage device 250 records three-dimensional data, i.e., design surface data, representing the shape of the design surface of the construction site in the global coordinate system. The global coordinate system is defined by the X-axis extending along the parallel of latitude. g Axis, Y extending along the meridian direction g Axis, Z extending along the vertical direction g A coordinate system consisting of axes. Design surface data, for example, is represented by TIN (Triangular Irregular Networks) data.

[0061] Software Structure

[0062] The processor 210 includes an operation signal acquisition unit 211, an input unit 212, a display control unit 213, a measurement value acquisition unit 214, a position and posture calculation unit 215, an intervention determination unit 216, a control signal output unit 218, a target posture determination unit 219, and a rotation amount calculation unit 220 for executing the control program.

[0063] The operation signal acquisition unit 211 acquires operation signals indicating the operation amount of each actuator from the operation device 271.

[0064] The input unit 212 receives operation input from the monitor device 272.

[0065] The display control unit 213 outputs the screen data displayed on the monitor device 272 to the monitor device 272.

[0066] The measurement value acquisition unit 214 acquires measurement values ​​from the tilt meter 401, the position and orientation meter 402, the boom angle sensor 403, the stick angle sensor 404, the bucket angle sensor 405, the tilt angle sensor 406, and the rotation angle sensor 407.

[0067] The position and posture calculation unit 215 calculates the position of the working 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 and posture calculation unit 215 calculates the position of the tip of the bucket 164 in the global coordinate system and the vehicle body coordinate system. The vehicle body coordinate system refers to an orthogonal coordinate system with a representative point of the rotating body 140 (e.g., a point passing through the center of rotation) as its origin. The calculations performed by the position and posture calculation unit 215 will be described later.

[0068] The intervention determination unit 216 determines whether to limit the speed of the working device 160 based on the position relationship between the tip of the bucket 164 calculated by the position and posture calculation unit 215 and the position of the design surface shown in the design surface data. Hereinafter, the speed limit of the working device 160 by the control device 200 will also be 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 this shortest distance is less than a predetermined distance, it determines to perform intervention control on the working device 160. Specifically, based on the measurement values ​​of the tilt meter 401 and the position and orientation meter 402, the intervention determination unit 216 rotates and moves the design surface data recorded in the storage 250 in parallel, thereby converting the position of the design surface represented by the global coordinate system to the position in the vehicle body coordinate system. The intervention determination unit 216 determines the contour point among the multiple contour points of the bucket 164 that is closest to the design surface as the control point. The intervention determination unit 216 determines the face (polygon) located vertically below the control point in the design surface data. Intervention determination unit 216 calculates the relationship between the bucket coordinate system and X through the control point. bk -Z bk The intersection of the parallel plane and the determined plane is the first design line. The intervention determination unit 216 determines whether the distance between the control point and the first design line is below the intervention threshold.

[0069] The control signal output unit 218 outputs control signals of each actuator (bucket cylinder 308, tilt cylinder 309, and rotary motor 310) corresponding to the operation amount obtained by the operation signal acquisition unit 211 or the target value calculated by the rotation amount calculation unit 220 to the control valve 303.

[0070] The functions of the target posture determination unit 219 and the rotation amount calculation unit 220 will be explained in detail in the description of the angle alignment function described later.

[0071] Calculation of Position and Posture Calculation Unit 215

[0072] Here, the method by which the position and posture calculation unit 215 calculates the position of a point on the outer shell of the working machine 100 is explained. The position and posture calculation unit 215 calculates the position of a point on the outer shell based on various measurement values ​​obtained by the measurement value acquisition unit 214 and geometric data recorded in the storage 250. The storage 250 records geometric data representing the dimensions of the slewing body 140, boom 161, stick 162, tilt-rotor 163 (mounting part 1631, tilting part 1632, and rotating part 1633), and bucket 164.

[0073] In the vehicle body coordinate system, which serves as the local coordinate system, the geometric data of the rotating body 140 represents the center position (x, y) of the joint axis supporting the boom 161 of the rotating body 140. bm y bm z bm The vehicle body coordinate system is an X-axis extending along the longitudinal direction with the rotation center of the rotating body 140° as the reference. sb The axis, the Y-axis extending in the left-right direction sb The axis, and the Z extending in the vertical direction. sb A coordinate system consisting of axes. It should be noted that the vertical direction of the rotating body 140° may not be consistent with the vertical direction.

[0074] In the boom coordinate system, which serves as the local coordinate system, the geometric data of boom 161 represents the position (x, y) of the joint axis by which boom 161 supports stick 162. am y am z am The boom coordinate system is based on the center position of the joint axis connecting the rotating body 140 and the boom 161, and is defined by the X-axis extending along the length direction. bm The axis, the Y-axis extending along the direction of the joint axis. bm Axis, and with X bm axis and Y bm Z-axis orthogonal bm A coordinate system formed by axes.

[0075] In the stick coordinate system, which serves as a local coordinate system, the geometric data of stick 162 represents the position (x, y) of the joint axis of the mounting portion 1631 of the tilt rotator 163 supported by stick 162. t1 y t1 z t1 The stick coordinate system is based on the center position of the joint axis connecting the boom 161 and the stick 162, and is defined by the X coordinate system extending along the length direction. amThe axis, the Y-axis extending along the direction of the joint axis. am Axis, and with X am axis and Y am Z-axis orthogonal am A coordinate system formed by axes.

[0076] In the first tilt-rotation coordinate system, which serves as a local coordinate system, the geometric data of the mounting portion 1631 of the tilt-rotator 163 represents the position (x, y) of the joint axis (x, y) of the mounting portion 1631 supporting the tilt portion 1632. t2 y t2 z t2 ) and the inclination of the joint axis (φ) t ). Inclination φ of the joint axis t This angle is related to the design error of the tilt rotator 163 and is obtained through calibration of the tilt rotator 163, etc. The first tilt rotation coordinate system is based on the center position of the joint axis connecting the stick 162 and the mounting part 1631, and extends along the direction of the joint axis connecting the stick 162 and the mounting part 1631. t1 The Z-axis extends in the direction of the joint axis connecting the mounting part 1631 and the tilting part 1632. t1 axis, and with Y t1 Axis and Z t1 orthogonal X-axis t1 A coordinate system formed by axes.

[0077] The geometric data of the tilting part 1632 of the tilting rotator 163 represent the position (x) of the front end of the rotation axis of the rotary motor 310 in the second tilting rotation coordinate system, which is a local coordinate system. t3 y t3 z t3 ) and the tilt of the rotation axis (φ) r Inclination φ of the rotation axis r This angle is related to the design error of the tilting rotator 163 and is obtained through calibration of the tilting rotator 163. The second tilting rotation coordinate system is based on the center position of the joint axis connecting the mounting part 1631 and the tilting part 1632, and extends along the direction of the joint axis connecting the mounting part 1631 and the tilting part 1632. t2 The Z-axis extends in the direction of the rotation axis of the rotary motor 310. t2 Axis, and with X t2 Axis and Z t2 orthogonal Y-axis t2 A coordinate system formed by axes.

[0078] The geometric data of the rotating part 1633 of the tilting rotator 163 represent the center position (x) of the mounting surface of the bucket 164 in the third tilting rotation coordinate system, which is a local coordinate system. t4y t4 z t4 The third tilting rotation coordinate system is based on the center position of the mounting surface of the bucket 164, and extends along the rotation axis of the rotary motor 310 in the Z direction. t3 The axis, X, orthogonal to the axis of rotation t3 Axis and Y t3 A coordinate system formed by the axes. It should be noted that the bucket 164 uses the tip of the bucket and the Y-axis as its coordinates. t3 It is mounted on the rotating part 1633 in a parallel manner.

[0079] The geometric data of bucket 164 represents the positions (x, y) of multiple contour points of bucket 164 in the third tilting rotation coordinate system. bk y bk z bk Examples of contour points include the two ends and the center of the tip of the bucket 164, the two ends and the center of the bottom of the bucket 164, and the two ends and the center of the rear of the bucket 164.

[0080] The position and posture calculation unit 215 calculates the boom angle θ obtained by the measurement value acquisition unit 214. bm The measured values ​​and geometric data of the rotating body 140 are used to generate the boom-body transformation matrix T for transforming from the boom coordinate system to the body coordinate system using the following mathematical formula (1). bm sb Boom-body conversion matrix T bm sb It is around Y bm Axis rotation boom angle θ bm And the deviation (x) between the origin of the vehicle body coordinate system and the origin of the boom coordinate system is parallel to the movement. bm y bm z bm A matrix of ).

[0081] [Mathematical Expression 1]

[0082]

[0083] The position and attitude calculation unit 215 calculates the stick angle θ obtained by the measurement value acquisition unit 214. am The measured values ​​and geometric data of boom 161 are used to generate the boom-boom transformation matrix T for transformation from the boom coordinate system to the boom coordinate system using the following mathematical formula (2). am bm boom-stick conversion matrix T am bm It is around Y am Axis rotation boom angle θ am And the deviation (x) between the origin of the boom coordinate system and the origin of the stick coordinate system is parallel to the movement.am y am z am The position and attitude calculation unit 215 calculates the boom-body transformation matrix T. bm sb With the boom-jib conversion matrix T am bm The product of these components generates the stick-to-vehicle transformation matrix T, used for transforming from the stick coordinate system to the vehicle coordinate system. am sb .

[0084] [Mathematical Expression 2]

[0085]

[0086] The position and posture calculation unit 215 calculates the bucket angle θ obtained by the measurement value acquisition unit 214. bk The measured values ​​and geometric data of the stick 162 are used to generate the first tilt-stick transformation matrix T for transformation from the first tilt-rotation coordinate system to the stick coordinate system through the following mathematical formula (3). t1 am First tilt-stick conversion matrix T t1 am It is around Y t1 Axis rotation bucket angle θ bk Furthermore, the deviation (x) between the origin of the parallel telescoping boom coordinate system and the origin of the first tilting and rotating coordinate system. t1 y t1 z t1 This causes the joint axis of the tilting part 1632 to tilt by an inclination φ. t The matrix. Additionally, the position and attitude calculation unit 215 calculates the boom-body transformation matrix T. am sb And the first tilt-stick conversion matrix T t1 am The product of these components generates the first tilt-body transformation matrix T, used for transforming from the first tilt-rotation coordinate system to the body coordinate system. t1 sb .

[0087] [Mathematical Expression 3]

[0088]

[0089] The position and attitude calculation unit 215 calculates the tilt angle θ obtained by the measurement value acquisition unit 214. t The measured values ​​and geometric data of the tilt rotator 163 are used to generate a second tilt-first tilt transformation matrix T for transforming from the first tilt rotation coordinate system to the second tilt rotation coordinate system using the following mathematical formula (4). t2t1 The second tilt-first tilt transformation matrix T t2 t1 It is around X t2 Axis rotation tilt angle θ t And the deviation (x) between the origin of the first tilting and rotating coordinate system and the origin of the second tilting and rotating coordinate system is shifted in parallel. t2 y t2 z t2 This causes the rotation axis of the rotating part 1633 to tilt by an inclination φ. r The matrix. Additionally, the position and attitude calculation unit 215 calculates the first tilt-body conversion matrix T. t1 sb Second tilt-first tilt transformation matrix T t2 t1 The product of these components generates the second tilt-body transformation matrix T, used for transforming from the second tilt-rotation coordinate system to the body coordinate system. t2 sb .

[0090] [Mathematical Expression 4]

[0091]

[0092] The position and attitude calculation unit 215 calculates the rotation angle θ obtained by the measurement value acquisition unit 214. r The measured values ​​and geometric data of the tilt rotator 163 are used to generate the third tilt-second tilt transformation matrix T for transforming from the second tilt rotation coordinate system to the third tilt rotation coordinate system using the following mathematical formula (5). t3 t2 The third tilt to second tilt transformation matrix T t3 t2 It is around Z t3 Axis rotation rotation angle θ r And the deviation (x) between the origin of the second tilting and rotating coordinate system and the origin of the third tilting and rotating coordinate system is shifted in parallel. t3 y t3 z t3 The matrix is ​​used for calculating the second tilt-body conversion matrix T. Additionally, the position and attitude calculation unit 215 calculates the second tilt-body conversion matrix T. t2 sb and the third tilt-second tilt transformation matrix T t3 t2 The product of these components generates the third tilt-body transformation matrix T, used for transforming from the third tilt-rotation coordinate system to the body coordinate system. t3 sb .

[0093] [Mathematical Expression 5]

[0094]

[0095] The position and posture calculation unit 215 calculates the center position (x) of the mounting surface of the bucket 164. t4 y t4 z t4 The positions (x, y) of multiple profile points in the third tilting rotation coordinate system shown by the geometric data of bucket 164 bk y bk z bk The sum of the third tilt-body conversion matrix T bk sb The product of these points can be used to determine the positions of multiple contour points of the bucket 164 in the vehicle body coordinate system.

[0096] However, the angle between the tip of the bucket 164 and the contact surface of the working machine 100, i.e., the X-axis of the vehicle coordinate system... sb -Y sb Y-axis of the plane and the third tilting and rotating coordinate system t3 The angle between the axes is determined by the boom angle θ. bm , pole angle θ am Bucket angle θ bk Tilt angle θ t and rotation angle θ r To determine this. Therefore, the position and attitude calculation unit 215, as... Figure 1 The diagram shows a bucket coordinate system originating from the center of the mounting surface of the bucket 164 at its base end, i.e., within the tilt rotator 163. This bucket coordinate system extends along the X-axis in the direction pointed towards the tip of the bucket 164. bk Axis, and X bk The Y axis is orthogonal to the tip of the bucket 164. bk Axis, and with X bk Axis and Y bk Z-axis orthogonal bk An orthogonal coordinate system formed by the axes. Hereafter, X will also be referred to as... bk The shaft is called the bucket tilting shaft, which tilts the Y-axis. bk The axis is called the bucket pitch axis, and Z is... bk The shaft is called the bucket rotation shaft. Bucket tilting shaft X bk Bucket pitch axis Y bk and the bucket rotation axis Z bk This is a hypothetical axis, different from the joint axis of the tilting rotator 163. It should be noted that when the tilt angle of the rotation axis of the rotary motor 310 is zero, the bucket coordinate system is consistent with the third tilting rotation coordinate system.

[0097] The position and attitude calculation unit 215 generates the bucket-third tilt transformation matrix T for transforming from the third tilt rotation coordinate system to the bucket coordinate system based on the geometric data of the tilt rotator 163 using the following mathematical formula (6).bk t3 Bucket - Third tilt transformation matrix T bk t3 It is to make the axis of rotation rotate around Y t3 Shaft rotation tilt φ r The matrix.

[0098] [Mathematical Expression 6]

[0099]

[0100] Angle alignment function

[0101] The angle alignment function of this embodiment will be described in detail below with reference to the accompanying drawings. Here, "angle alignment" refers to aligning the bucket 164 around the bucket tilt axis (X). bk The axis rotates, causing the bucket tip of the bucket 164 to be oriented (bucket pitch axis (Y)). bk The operation of the axis relative to the vehicle body reference plane is called the specified angle. The vehicle body reference plane refers to the X-axis in the vehicle body coordinate system. sb Y-axis sb Axial plane (reference) Figure 1 In this embodiment, the specified angle refers to the angle at which the shovel tip is parallel to the vehicle body reference plane. This operation allows the shovel tip to be parallel to the vehicle body reference plane without changing the opening direction (bucket tilt axis) of the bucket 164. It should be noted that the specified angle is not limited to the angle at which the shovel tip is parallel to the vehicle body reference plane; it can also be an angle arbitrarily determined by the operator.

[0102] First of all, Figure 4 The operation signal acquisition unit 211, control signal output unit 218, target posture determination unit 219, and rotation amount calculation unit 220 are described in detail.

[0103] In addition to acquiring the functions described above, the operation signal acquisition unit 211 also acquires the operation signal to the dedicated operation receiving unit (hereinafter also referred to as the angle alignment operation receiving unit) in the operation device 271 for using the angle alignment function.

[0104] When the target posture determination unit 219 receives an operation signal from the operation receiving unit for angle alignment, it determines to rotate the bucket 164 about an imaginary rotation axis by a predetermined amount from its current posture, i.e., the target posture. The imaginary rotation axis is an imaginary rotation axis pointing towards the opening direction of the bucket 164. In this embodiment, the bucket tilt axis (X) in the aforementioned bucket coordinate system is... bk Axis, Reference Figure 1The reference axis is determined as the imaginary axis of rotation. The target posture refers to the posture in which a reference axis orthogonal to the imaginary axis of rotation forms a specified angle with respect to a specified surface. The reference axis is an axis extending along the tip of the bucket 164, and in this embodiment, it is the bucket pitch axis (Y) in the bucket coordinate system described above. bk Axis, Reference Figure 1 The specified surface refers to the reference surface of the vehicle body.

[0105] The rotation calculation unit 220 calculates the rotation amount of each of the multiple rotating mechanisms required to make the current posture of the bucket 164 match the target posture. Here, in this embodiment, the multiple rotating mechanisms are the bucket cylinder 308, the tilt cylinder 309, and the rotary motor 310. For example... Figures 1-2 As shown, bucket cylinder 308 causes bucket 164 to rotate around axis Yt1. Tilting cylinder 309 causes bucket 164 to rotate around axis Xt1. t2 The shaft rotates. Additionally, the rotary motor 310 causes the bucket 164 to rotate around the Z-axis. t3 The shaft rotates.

[0106] Next, while referring to Figures 5-8 The process of handling the angle alignment function of the control device 200 in this embodiment will be explained.

[0107] Figure 5 This is a flowchart illustrating the angle alignment function in the first embodiment. When the operator of the work machinery 100 begins operation of the work machinery 100, the control device 200 executes the control shown below every predetermined control cycle (e.g., 1000 milliseconds).

[0108] First, the measurement value acquisition unit 214 acquires the measurement values ​​of the tilt meter 401, the position and orientation meter 402, the boom angle sensor 403, the stick angle sensor 404, the bucket angle sensor 405, the tilt angle sensor 406, and the rotation angle sensor 407 (step S101).

[0109] The position and posture calculation unit 215 calculates the posture of the bucket in the vehicle coordinate system based on the measurement values ​​obtained in step S101 (step S102). The posture of the bucket in the vehicle coordinate system is determined by each axis (X) of the bucket coordinate system in the vehicle coordinate system. bk Y bk Z bk The orientation matrix R of the direction cur The pose matrix R represents the pose of bucket 164. cur All parallel translation components are zero.

[0110] The operation signal acquisition unit 211 acquires the operation signal from the angle alignment operation receiving unit from the operator (step S103).

[0111] In this embodiment, the operating device 271 includes, for example, the following: Figure 6 The two levers 2710 and 2711 are shown. The working machine 100 of this embodiment is the same as a conventional working machine. By tilting the two levers 2710 and 2711 in the forward / backward and left / right directions, the operator can respectively operate the rotation of the slewing body 140 and the boom angle θ. bm , pole angle θ am and bucket angle θ bk Furthermore, the operator can control the tilt angle θ via the tilt rotator 163 by operating the operation receiving parts (buttons, slide switches, dials, proportional roller switches) provided on the upper surface of each lever 2710, 2711. t and rotation angle θ r .

[0112] Furthermore, the operating device 271 of this embodiment has an angle alignment operation receiving unit 2710b on the lever 2710. The angle alignment operation receiving unit 2710b is, for example, a press-type mechanical switch. By pressing this switch, the operator can perform angle alignment control at a desired timing. When the processor receives a signal from the angle alignment operation receiving unit 2710b, it determines that the prescribed control start condition has been met and proceeds to step S104.

[0113] return Figure 5 Next, the target posture determination unit 219 will tilt the bucket axis X bk The axis of rotation is determined as an imaginary axis, and the tilting axis X around the bucket is determined. bk The target value of angular velocity θ bk_t_tgt (Step S104). It should be noted that the target value θ bk_t_tgt It can also be a pre-set fixed value. It should be noted that the target value θ for determining the angular velocity about the bucket tilt axis Xbk is... bk_t_tgt Synonymous with determining the target posture that bucket 164 should be in after a unit of time elapsed from the current moment.

[0114] Next, the rotation calculation unit 220 calculates the target value θ determined by the target posture determination unit 219. bk_t_tgt Calculate the target values ​​of the rotation amounts of each of the multiple rotating mechanisms required to make the current posture of the bucket 164 match the target posture (step S105).

[0115] Specifically, the rotation calculation unit 220 calculates the target value θ of the angular velocity. bk_t_tgt Substitute the following mathematical expression (7) to construct the bucket tilt axis X in the bucket coordinate system. bk The rotation matrix R of the rotation bk_t bk .

[0116] [Mathematical Expression 7]

[0117]

[0118] The rotation calculation unit 220 calculates the rotation amount by using the matrix R representing the current posture of the bucket 164. cur Multiply by the rotation matrix R of mathematical expression (7) bk-p bk To calculate the target posture R of the bucket 164 after a unit of time. tgt Furthermore, the rotation calculation unit 220 calculates the rotation amount based on the current posture R of the bucket 164. cur The target posture R of the bucket after unit time 164 tgt The bucket angle θ can be calculated using the following mathematical formulas (8), (9), and (10). bk Tilt angle θ t and rotation angle θ r Their respective target values ​​(θ) bk_tgt θ t_tgt θ r_tgt ).

[0119] [Mathematical Expression 8]

[0120]

[0121] [Mathematical Expression 9]

[0122]

[0123] [Mathematical Expression 10]

[0124]

[0125] As described above, through matrix transformation, the target value (θ) of the angular velocity about an imaginary rotation axis (bucket tilt axis) is... bk_t_tgt The target value (θ) is converted into the angular velocity about the three mechanical axes. bk_tgt θ t_tgt θ r_tgt ).

[0126] Next, the control signal output unit 218 generates the signal related to the bucket angle θ. bk Tilt angle θ t and rotation angle θ r Their respective target values ​​(θ) bk_tgt θ t_tgt θ r_tgt The control signals of each actuator (bucket cylinder 308, tilt cylinder 309 and rotary motor 310) are sent to the control valve 303 (step S106).

[0127] The control signal output unit 218 outputs control signals for each actuator to the control valve 303, thereby causing an actual change in the posture of the bucket 164. At this time, the target posture determination unit 219 obtains the changed current posture R. cur Determine whether the bucket pitch axis is parallel to the vehicle body reference plane (step S107).

[0128] Bucket pitch axis (Y bk If the tilt axis (X) is not parallel to the vehicle body reference plane (step S107; no), return to step S104 and re-determine the tilt axis (X) around the bucket. bk The target value of the angular velocity (θ) of the axis bk_t_tgt Therefore, the processing of step S105 performed by the rotation amount calculation unit 220 and the processing of step S106 performed by the control signal output unit 218 are executed again.

[0129] On the other hand, the bucket pitch axis (Y) bk When the axis is parallel to the vehicle body reference plane (step S107; Yes), the target posture determination unit 219, the rotation amount calculation unit 220, and the control signal output unit 218 finish processing. Thus, the automatic angle alignment control performed by the control device 200 is completed.

[0130] Function / Effect

[0131] Next, while referring to Figure 7 , Figure 8 The effects of the angle alignment function will be explained.

[0132] Figure 7 , Figure 8 This indicates the situation of observing the working machine 100 from the same angle.

[0133] Here, Figure 7 Indicates the direction of the bucket tip (bucket pitch axis (Y)) of bucket 164. bk (axis) relative to the vehicle body reference plane (X) sb -Y sb The state after excavation (shoveling) in a tilted (flat) position. The operator of the work machinery 100 loads the load onto the dump truck from this state.

[0134] To load the excavated soil into the dump truck, the operator operates the boom 161 and stick 162 to lift the bucket 164 upwards. However, with the tip of the bucket 164 tilted, some of the excavated soil spills out of the bucket 164. Therefore, while operating the boom 161 and stick 162 via levers 2710 and 2711, the operator presses the operation receiving unit 2710b (see reference). Figure 6 Therefore, bucket 164 automatically rotates around the bucket tilt axis (X). bkThe bucket pitch axis (Y) rotates, and the bucket tilt axis (Y) rotates. bk The axis is controlled to be parallel to the vehicle body reference plane.

[0135] Figure 8 This indicates the state immediately after the automatic angle alignment control is completed. For example... Figure 8 As shown, the direction of the bucket tip (bucket pitch axis (Y)) of bucket 164 bk The axis is parallel to the vehicle body reference plane. On the other hand, the opening direction of the bucket 164 (bucket tilt axis (X)) is parallel to the vehicle body reference plane. bk The shaft remains unchanged. Therefore, after dumping soil into the dump truck, when returning the bucket 164 to the excavation face, the opening face is maintained in alignment with the excavation face.

[0136] According to the control device 200 of the first embodiment, in the working machine 100 which is equipped with a working device 160 consisting of multiple rotating mechanisms (bucket cylinder 308, tilt cylinder 309 and rotary motor 310) and a bucket 164, the operation of making the tip of the bucket 164 parallel to the reference plane of the vehicle body can be simplified.

[0137] (A variation of the first embodiment)

[0138] In the first embodiment described above, it is explained that the operator can initiate angle alignment control at a desired timing by pressing the operation receiving unit 2710b. That is, in the first embodiment, the control start condition for the angle alignment function is the operator's operation (pressing the button). However, other embodiments are not limited to this method. For example, the control device 200 of the modified example of the first embodiment may also have the following functions.

[0139] In a variation of the first embodiment, the target posture determination unit 219, as a control start condition for the angle alignment function, begins the process of determining the target posture when the bucket 164 moves a predetermined distance away from the ground.

[0140] The determination of whether the bucket 164 has moved away from the ground by a predetermined distance can be achieved, for example, using the function of the intervention determination unit 216 described above. That is, the target posture determination unit 219 calculates the shortest distance between the position of the bucket tip 164 and the design surface at all times via the intervention determination unit 216. Then, during the rising of the bucket 164 after scooping, the target posture determination unit 219 determines that the predetermined control start condition has been met when the shortest distance calculated at all times reaches or exceeds a predetermined determination threshold, and begins the processing of step S104.

[0141] Therefore, operator intervention can be eliminated when performing angle alignment control, further simplifying the loading operation onto the loading platform.

[0142] <Other Implementation Methods>

[0143] The above description of one embodiment, with reference to the accompanying drawings, is detailed, but the specific structure is not limited to the above method, and various design changes are possible. That is, in other embodiments, the order of the above processes can be appropriately changed. Furthermore, some processes can be executed in parallel.

[0144] The control device 200 described in the above embodiments can be a device composed of a single computer, or it can be a device in which the components of the control device 200 are separately configured on multiple computers and function as a control device 200 through mutual cooperation among the multiple computers. In this case, it is also possible that the computer constituting part of the control device 200 is installed inside the work machinery, while other computers are located outside the work machinery. For example, in other embodiments, the operating device 271 and the monitoring device 272 may be remotely installed from the work machinery 100, and the components of the control device 200 other than the measurement value acquisition unit 214 and the control signal output unit 218 may be installed on a remote server.

[0145] Furthermore, while the work machine 100 in the above embodiment is a hydraulic excavator, it is not limited to this. For example, the work machine 100 in other embodiments may also be a non-self-propelled work machine fixed to the ground. Additionally, the work machine 100 in other embodiments may also be a work machine without a rotating body.

[0146] The work machine 100 of the above-described embodiment includes a bucket 164 as an accessory to the working device 160, but is not limited to this. For example, the work machine 100 of other embodiments may also include a breaker, fork, grab bucket, etc., as accessories. In this case, the control device 200 is also connected to the bucket coordinate system via an X-axis extending in the direction along the tip of the accessory. bk The axis, Y, extending in the direction along the shovel tip. bk Axis, and X bk axis and Y bk Z-axis orthogonal bk The tilt rotator 163 is controlled by a local coordinate system composed of axes.

[0147] In other embodiments, the axes of the tilting rotator 163 may or may not be orthogonal, as long as they intersect on different planes. Specifically, the planes parallel to axes AX1 (connecting the boom 162 to the mounting portion 1631), AX2 (connecting the mounting portion 1631 to the tilting portion 1632), and AX3 (the rotation axis of the rotary motor 310) may be different when the tilting angle and rotation angle of the tilting rotator 163 are zero.

[0148] Alternatively, the control device 200 in other embodiments may not have a design surface setting function. In such cases, the control device 200 can also automatically control the tilt rotator 163 by performing bucket posture holding control. For example, the operator can perform simple land preparation operations without setting a design surface.

[0149] Industrial availability

[0150] According to the above method, in a working machine having a working tool supported on a working device via a tilting rotator, it is possible to simplify the operation of aligning the second reference direction with a specified surface without changing the first reference direction of the working tool.

[0151] Explanation of reference numerals in the attached figures

[0152] 100…Working machinery; 120…Traveling body; 140…Rotating body; 160…Working device; 161…Boom; 162…Stick; 163…Tilting rotator; 1631…Mounting unit; 1632…Tilting unit; 1633…Rotating unit; 164…Bucket; 180…Cab; 200…Control device; 210…Processor; 211…Operation signal acquisition unit; 212…Input unit; 213…Display control unit; 214…Measurement value acquisition unit; 215…Position and posture calculation unit; 216…Intervention determination unit; 218…Control signal output unit; 219…Target posture determination unit; 220…Rotation… 230… Main memory; 250… Storage device; 270… Interface; 271… Operating device; 272… Monitor device; 301… Engine; 302… Hydraulic pump; 303… Control valve; 304… Travel motor; 305… Swing motor; 306… Boom cylinder; 307… Stick cylinder; 308… Bucket cylinder; 309… Tilting cylinder; 310… Rotary motor; 401… Tilt meter; 402… Position and orientation meter; 403… Boom angle sensor; 404… Stick angle sensor; 405… Bucket angle sensor; 406… Tilt angle sensor; 407… Rotation angle sensor.

Claims

1. A system for controlling a working machine, the working machine comprising: a working device supported on a vehicle body in an actuating manner; a tilting rotator mounted at the front end of the working device; and a working tool supported on the working device via the tilting rotator in a manner rotatable about three axes intersecting joint axes in mutually different planes, wherein... The system for controlling the operating machinery includes a processor. In the processor, Measurement values ​​are obtained from multiple sensors. Based on the measured values, the current posture of the working tool is calculated. Under the condition that the prescribed control start conditions are met, based on the calculated current posture of the working tool, a hypothetical rotation axis is determined that is defined separately from the three axes and extends along the opening direction of the working tool. Generate a control signal for the tilt rotator to rotate the working tool about the imaginary rotation axis by a predetermined amount in a manner that changes the working tool from the current posture to the target posture. The generated control signal is output.

2. The system according to claim 1, wherein, The working tool has a shovel tip. The imaginary axis of rotation is an axis that extends in the direction in which the tip of the shovel of the working tool is facing.

3. The system according to claim 2, wherein, In the processor, Determine a reference axis that is orthogonal to the imaginary axis of rotation and extends along the tip of the tool. The posture in which the reference axis is parallel to the vehicle body reference plane is set as the target posture.

4. The system according to any one of claims 1 to 3, wherein, In the processor, Obtain the prescribed operation signal from the operator. As a specified control start condition, upon receiving the specified operation signal, a control signal is generated to rotate the tilt rotator by a specified amount around the imaginary rotation axis in such a way that the current posture of the working tool becomes the target posture.

5. The system according to any one of claims 1 to 3, wherein, In the processor, the target posture is determined as a predetermined control start condition when the working tool leaves the ground a predetermined distance.

6. The system according to any one of claims 1 to 3, wherein, The imaginary axis of rotation extends in a direction different from the joint axis of the tilting rotator.

7. A method for controlling a working machine, the working machine comprising: a working device supported on a vehicle body in an actuating manner; a tilting rotator mounted at the front end of the working device; and a working tool supported on the working device via the tilting rotator in a manner rotatable about three axes intersecting joint axes in mutually different planes, wherein... The method for controlling the operating machinery includes: The steps to obtain measurement values ​​from multiple sensors; The step of calculating the current posture of the working tool based on the measured values; Under the condition that the prescribed control start conditions are met, the step of determining an imaginary rotation axis that is defined separately from the three axes and extends along the opening direction of the working tool based on the calculated current posture of the working tool; The steps of generating a control signal for rotating the tilting rotator by a predetermined amount about the imaginary rotation axis in a manner that causes the working tool to rotate from the current posture to the target posture; and The step of outputting the generated control signal.

8. A storage medium, wherein, The storage medium stores a program that enables a computer of a control system for a work machine having a working device supported on a vehicle body in an actuating manner, a tilting rotator mounted at the front end of the working device, and a working tool supported on the working device via the tilting rotator in a manner that allows rotation about three axes—joint axes intersecting on mutually different planes—to execute. The steps to obtain measurement values ​​from multiple sensors; The step of calculating the current posture of the working tool based on the measured values; Under the condition that the prescribed control start conditions are met, the step of determining an imaginary rotation axis that is defined separately from the three axes and extends along the opening direction of the working tool based on the calculated current posture of the working tool; The step of generating a control signal for rotating the tilt rotator about the imaginary axis of rotation by a predetermined amount so that the working tool rotates from the current posture to the target posture by a predetermined amount; as well as The step of outputting the generated control signal.

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