CONTROL SYSTEM FOR A CONSTRUCTION MACHINE, CONSTRUCTION MACHINE AND CONTROL METHOD FOR A CONSTRUCTION MACHINE

Abstract

A control system (200) for a construction machine (100) provided with a work implement (1) comprising an arm (7) and a bucket (8), the bucket (8) being configured to rotate about each of a bucket axis (AX3) and a tilt axis (AX4) orthogonal to the bucket axis (AX3) with respect to the arm (7), and the bucket (8) having designation points (RP) defined on an outer surface, the designation points (RP) comprising at least a first designation point (RPa) and a second designation point (RPb) specified on both sides in a width direction of the bucket (8) at the cutting edge (9) thereof, the control system comprising: a destination point position data calculation unit (53) configured to calculate position data of the destination points (RPa, RPb) and a direction vector (Vec_ab) based on the position data of the first and second destination points (RPa, RPb), the direction vector (Vec_ab) connecting the first destination point (RPa) and the second destination point (RPb); an angle determination unit (57) configured to calculate an intersection vector (STr) between a tilting operation plane (TP) passing through at least one of the determination points (RP) and being orthogonal to the tilting axis (AX4) and a target construction topography (CS) indicating a target shape of an excavation object, and to determine a tilting angle (δ) based on the direction vector (Vec_ab) and the intersection vector (STr) indicating an angle of a specific portion of the bucket (8) around the tilting axis (AX4) so that the target construction topography (CS) and the specific portion of the bucket (8) become parallel to each other, and a work implement control unit (58) configured to control a tilt cylinder (14) configured to rotate the bucket (8) about the tilt axis (AX4) on the basis of the tilt angle (δ) determined by the angle determining unit (57).

Description

Area

[0001] The present invention relates to a control system for a construction machine, a construction machine and a control method for a construction machine. background

[0002] A construction machine equipped with a working device comprising a tilting bucket, as disclosed in WO 2015 / 186 179 A1, is known. WO 2016 / 052 762 A1 discloses a hydraulic excavator with a working device and a working device control unit. The working device control unit is configured to automatically control the working device with a bucket by means of a tilt axis angle calculation unit such that it assumes part of the grading work. WO 2016 / 076 444 A1 discloses a hydraulic excavator with a working device and a control system configured to control the movement of the bucket using a bucket information calculation unit and a tilt axis angle calculation unit. DE 11 2013 000 124 T5 discloses a display system of an earthmoving machine with a bucket. The display system is configured to display a bucket attitude based on an edge inclination angle on a screen. SummaryTechnical problem

[0003] In a technical field related to the control of construction machinery, a technology for controlling the work tool that is preferred to the operation of an operating device by a construction machine operator is known. In this specification, a work tool control that is preferred to the operation of the operating device by the construction machine operator is referred to as intervention control.

[0004] In intervention control, a position or posture of at least one of a boom, an arm, and a bucket of the work equipment is controlled with respect to a target construction topography that indicates a target shape of an excavated object. Intervention control is performed, and thus, a construction project conforming to the target construction topography is carried out.

[0005] If the construction machine including the dump bucket does not implement dump bucket specific control in addition to the existing intervention control, the working efficiency of the construction machine will deteriorate.

[0006] An object of the invention is to provide a control system for a construction machine capable of counteracting the deterioration of work efficiency in a construction machine provided with a work implement including a dump bucket, a construction machine, and a control method for a construction machine. Solution to the problem

[0007] According to a first aspect of the present invention, a control system for a construction machine provided with a work implement including an arm and a bucket, the bucket being configured to rotate about each of a bucket axis and a tilt axis orthogonal to the bucket axis with respect to the arm, and the bucket having designation points defined on an outer surface, the designation points including at least a first designation point and a second designation point specified on both sides in a width direction of the bucket at the cutting edge thereof, the control system comprising: a designation point position data calculation unit configured to calculate position data of the designation points and a direction vector based on the position data of the first and second designation points, the direction vector connecting the first and second designation points;an angle determination unit configured to calculate an intersection vector between a tilting operation plane passing through at least one of the determination points and orthogonal to the tilt axis and a target construction topography indicating a target shape of an excavation object, and to determine a tilt angle based on the direction vector and the intersection vector indicating an angle of a specific portion of the bucket around the tilt axis so that the target construction topography and the specific portion of the bucket become parallel to each other; and a work implement control unit configured to control a tilt cylinder configured to rotate the bucket around the tilt axis based on the tilt angle determined by the angle determination unit.

[0008] According to a second aspect of the present invention, a construction machine comprises: an upper swing body; a lower traveling body configured to support the upper swing body; a work implement including the arm and the bucket, the work implement configured to be supported on the upper swing body; and the control system according to the first aspect.

[0009] According to a third aspect of the present invention, there is provided a control method for a construction machine equipped with a work implement having an arm and a bucket, the bucket being configured to rotate about a bucket axis and a tilt axis orthogonal to the bucket axis with respect to the arm, respectively, and the bucket having designation points defined on an outer surface, the designation points including at least a first designation point and a second designation point specified on both sides in a width direction of the bucket at the cutting edge thereof, the control method comprising: calculating, by a designation point position data calculation unit, position data of the designation points and a direction vector based on the position data of the first and second designation points, the direction vector connecting the first and second designation points;Calculating, by means of an angle determination unit, an intersection vector between a tilting operation plane passing through at least one of the determination points and being orthogonal to the tilt axis and a target construction topography indicating a target shape of an excavation object, and determining a tilt angle based on the direction vector and the intersection vector indicating an angle of a specific portion of the bucket around the tilt axis so that the target construction topography and the specific portion of the bucket become parallel to each other; and controlling a tilt cylinder configured to rotate the bucket around the tilt axis based on the determined tilt angle. Advantageous effects of the invention

[0010] According to the aspects of the invention, a control system for a construction machine capable of counteracting deterioration of work efficiency in a construction machine provided with a work implement having a dump bucket, a construction machine, and a control method for a construction machine are provided. Short description of the drawings Fig. 1 is a perspective view showing an example of a construction machine according to this embodiment. Fig. 2 is a side cross-sectional view showing an example of a bucket according to this embodiment. Fig. 3 is a front view showing an example of the bucket according to this embodiment. Fig. 4 is a side view schematically showing an excavator according to this embodiment. Fig. 5 is a rear view schematically showing the excavator according to this embodiment. Fig. 6 is a plan view schematically showing the excavator according to this embodiment. Fig. Fig. 7 is a side view schematically showing the bucket according to this embodiment. Fig. Fig. 8 is a front view schematically showing the bucket according to this embodiment. Fig. 9 is a schematic view showing an example of a hydraulic system according to this embodiment. Fig. 10 is a schematic view showing an example of the hydraulic system according to this embodiment. Fig. 11 is a functional block diagram showing an example of a control system according to this embodiment. Fig. 12 is a view schematically illustrating an example of a defining point set on the bucket according to this embodiment. Fig. 13 is a schematic view showing an example of target construction data according to this embodiment. Fig. 14 is a schematic view illustrating an example of a target construction topography according to this embodiment. Fig. 15 is a schematic view showing an example of a tilting operation plane according to this embodiment. Fig. 16 is a schematic view showing an example of the tilting operation plane according to this embodiment. Fig. 17 is a view schematically illustrating a relationship between a cutting edge of the bucket and the target construction topography according to this embodiment. Fig. 18 is a schematic view illustrating engagement control with respect to tilt rotation according to this embodiment. Fig. 19 is a view illustrating an example of a relationship between an operating distance and a target speed according to this embodiment. Fig. 20 is a flowchart showing an example of a method for adjusting a tilt angle of the bucket according to this embodiment. Fig. 21 is a schematic view showing an example of the method for adjusting the tilt angle of the bucket according to this embodiment. Fig. 22 is a view schematically illustrating an example of an operation of a working device according to this embodiment. Fig. 23 is a view schematically illustrating an example of the operation of the working device according to this embodiment. Fig. 24 is a flowchart showing an example of the method for adjusting the tilt angle of the bucket according to this embodiment. Fig. 25 is a schematic view showing an example of the method for adjusting the tilt angle of the bucket according to this embodiment. Fig. Fig. 26 is a schematic view illustrating an example of the method for adjusting the tilt angle of the bucket according to this embodiment. Description of the Embodiments

[0011] Embodiments of the invention will now be described with reference to the accompanying drawings.

[0012] In the following description, a positional relationship of the respective sections is described by specifying a three-dimensional global coordinate system (Xg, Yg and Zg) and a three-dimensional vehicle body coordinate system (Xm, Ym and Zm).

[0013] The global coordinate system represents a coordinate system in which the origin point fixed on the sphere is used as a reference. The global coordinate system is a coordinate system defined by a global navigation satellite system (GNSS). The GNSS represents a global navigation satellite system. An example of a global navigation satellite system is the global positioning system (GPS). The GNSS comprises multiple positioning satellites. The GNSS records a position defined by coordinate data of latitude, longitude, and altitude.

[0014] The global coordinate system is defined by an Xg axis in a horizontal plane, a Yg axis orthogonal to the Xg axis in the horizontal plane, and a Zg axis orthogonal to the Xg axis and the Yg axis. A direction parallel to the Xg axis is defined as the Xg axis direction, a direction parallel to the Yg axis is defined as the Yg axis direction, and a direction parallel to the Zg axis is defined as the Zg axis direction. In addition, a rotation or tilt direction around the Xg axis is defined as a θXg direction, a rotation or tilt direction around the Yg axis is defined as a θYg direction, and a rotation or tilt direction around the Zg axis is defined as a θZg direction. The Zg axis direction is a vertical direction.

[0015] The vehicle body coordinate system represents a coordinate system in which the origin point fixed on the construction machine is set as a reference.

[0016] The vehicle body coordinate system is defined by an Xm axis extending in a direction with the origin point on a vehicle body of a construction machine as a reference, a Ym axis orthogonal to the Xm axis, and a Zm axis orthogonal to both the Xm axis and the Ym axis. A direction parallel to the Xm axis is designated as the Xm axis direction, a direction parallel to the Ym axis is designated as the Ym axis direction, and a direction parallel to the Zm axis is designated as the Zm axis direction. In addition, a rotation or tilt direction around the Xm axis is designated as a θXm direction, a rotation or tilt direction around the Ym axis is designated as a θYm direction, and a rotation or tilt direction around the Zm axis is designated as a θZm direction.The Xm axis direction is a forward and backward direction of the construction machine, the Ym axis direction is the vehicle width direction of the construction machine, and the Zm axis direction is an upper and lower direction of the construction machine. First embodiment[Construction machine]

[0017] Fig. 1 is a perspective view illustrating an example of a construction machine 100 according to this embodiment. In this embodiment, an example in which the construction machine 100 is an excavator will be described. In the following description, the construction machine 100 will be appropriately referred to as an excavator 100.

[0018] As in Fig. 1, the excavator 100 includes a work machine 1 operated by hydraulic pressure, an upper swing body 2, which is a vehicle body supporting the work machine 1, and a lower traveling body 3, which is a traveling device supporting the upper swing body 2, an operating device 30 that operates the work machine 1, and a control device 50 that controls the work machine 1. The upper swing body 2 can swing about a swing axis RX in a state where it is supported on the lower traveling body 3.

[0019] The upper swing body 2 includes a driver's compartment 4 in which an operator rides, and a machine compartment 5 in which an engine and a hydraulic pump are housed. The driver's compartment 4 includes a driver's seat 4S on which the operator sits. The machine compartment 5 is located at a rear side of the driver's compartment 4.

[0020] The lower traveling body 3 includes a pair of crawler tracks 3C. The excavator 100 travels due to the rotation of the crawler tracks 3C. Furthermore, the lower traveling body 3 may have tires.

[0021] The work machine 1 is supported on the upper swing body 2. The work machine 1 includes a boom 6 connected to the upper swing body 2 via a boom pin, an arm 7 connected to the boom 6 via an arm pin, and a bucket 8 connected to the arm 7 by a bucket pin and a tilt pin. The bucket 8 has a cutting edge 9. In this embodiment, the cutting edge 9 of the bucket 8 is a tip end of a straight bucket provided in the bucket 8. Further, the cutting edge 9 of the bucket 8 may be a tip end of a convex cutting edge provided in the bucket 8.

[0022] The boom 6 can rotate about a boom axis AX1, which is a rotation axis with respect to the upper swing body 2. The arm 7 can rotate about an arm axis AX2, which is a rotation axis with respect to the boom 6. The bucket 8 can rotate about a bucket axis AX3, i.e., a rotation axis, and a tilt axis AX4, i.e., a rotation axis orthogonal to the bucket axis AX3 with respect to the arm 7. The rotation axis AX1, the rotation axis AX2, and the rotation axis AX3 are parallel to each other. The rotation axes AX1, AX2, and AX3 and an axis parallel to the swing axis RX are orthogonal to each other. The rotation axes AX1, AX2, and AX3 are parallel to the Ym axis of the vehicle body coordinate system. The swing axis RX is parallel to the Zm axis of the vehicle body coordinate system. A direction parallel to the rotation axes AX1, AX2 and AX3 represents a vehicle width direction of the upper swivel body 2.A direction parallel to the swing axis RX represents an upper and lower direction of the upper swing body 2. A direction orthogonal to both the rotation axes AX1, AX2, and AX3 and the swing axis RX represents a forward and backward direction of the upper swing body 2. A direction in which the work machine 1 is located based on the operator sitting on the operator's seat 4S is a forward side.

[0023] The work tool 1 operates with the power generated by a hydraulic cylinder 10. The hydraulic cylinder 10 includes a boom cylinder 11 that operates the boom 6, an arm cylinder 12 that operates the arm 7, and a bucket cylinder 13 and a tilt cylinder 14 that operate the bucket 8. The boom cylinder 11 can generate a force to rotate the boom 6 about the boom axis AX1. The arm cylinder 12 can generate a force to rotate the arm 7 about an arm axis AX2. The bucket cylinder 13 can generate a force to rotate the bucket 8 about a bucket axis AX3. The tilt cylinder 14 can generate a force to rotate the bucket 8 about a tilt axis AX4.

[0024] In the following description, the rotation of the bucket 8 about the bucket axis AX3 is appropriately referred to as bucket rotation, and the rotation of the bucket 8 about the tilt axis AX4 is appropriately referred to as tilt rotation.

[0025] In addition, the work machine 1 includes a boom lift sensor 16 that detects a boom lift indicating the drive amount of the boom cylinder 11, an arm lift sensor 17 that detects an arm lift indicating the drive amount of the arm cylinder 12, a bucket lift sensor 18 that detects a bucket lift indicating the drive amount of the bucket cylinder 13, and a tilt lift sensor 19 that detects a tilt lift indicating the drive amount of the tilt cylinder 14. The boom lift sensor 16 is arranged on the boom cylinder 11. The arm lift sensor 17 is arranged on the arm cylinder 12. The bucket lift sensor 18 is arranged on the bucket cylinder 13. The tilt lift sensor 19 is arranged on the tilt cylinder 14.

[0026] The operating device 30 is arranged in the operator compartment 4. The operating device 30 includes an operating member operated by an operator of the excavator 100. The operator operates the work machine 1 by operating the operating device 30. In this embodiment, the operating device 30 includes a right work machine operating lever 30R, a left work machine operating lever 30L, a tilting operation lever 30T, and an operating pedal 30F.

[0027] When the right work tool operation lever 30R, which is in the neutral position, is operated to a forward side, the boom 6 operates downward, and when the right work tool operation lever 30R is operated to a reverse side, the boom 6 operates upward. When the right work tool operation lever 30R, which is in the neutral position, is operated to the right, the bucket 8 performs dumping, and when the right work tool operation lever 30R is operated to the left, the bucket 8 performs excavation.

[0028] When the left work tool operating lever 30L, which is in the neutral position, is operated to a forward side, the arm 7 performs dumping, and when the left work tool operating lever 30L is operated to a reverse side, the arm 7 performs excavation. When the left work tool operating lever 30L, which is in the neutral position, is operated to the right, the upper swing body 2 swings to the right, and when the left work tool operating lever 30L is operated to the left, the upper swing body 2 swings to the left.

[0029] Further, the relationship between the operating direction of the right work implement operating lever 30R and the left work implement operating lever 30L and the operating direction of the work implement 1 and the swing direction of the upper swing body 2 may not be the relationship described above.

[0030] The control device 50 includes a computer system. The control device 50 includes a processor such as a central processing unit (CPU), a storage device including non-volatile memory such as read-only memory (ROM) and volatile memory such as random access memory (RAM), and an input / output interface device. [Spoon]

[0031] Next, the bucket 8 according to this embodiment will be described. Fig. 2 is a side cross-sectional view showing an example of the bucket 8 according to this embodiment. Fig. 3 is a front view showing an example of the bucket 8 according to this embodiment. In this embodiment, the bucket 8 is a tilting bucket.

[0032] As in Fig. 2 and Fig. As shown in Figure 3, the work tool 1 includes the bucket 8, which can rotate about the bucket axis AX3 and the tilt axis AX4 orthogonal to the bucket axis AX3 with respect to the arm 7. The bucket 8 is rotatably connected to the arm 7 via a bucket pin 8B. Furthermore, the bucket 8 is rotatably supported on the arm 7 by a tilt pin 8T.

[0033] The bucket 8 is connected to a tip end of the arm 7 through a link 90. The bucket pin 8B connects the arm 7 and the link 90. The rocker pin 8T connects the link 90 and the bucket 8. The bucket 8 is rotatably connected to the arm 7 through the link 90.

[0034] The bucket 8 includes a bottom plate 81, a back plate 82, a top plate 83, a side plate 84, and a side plate 85. An opening 86 of the bucket 8 is defined by the top plate 81, the top plate 83, the side plate 84, and the side plate 85. The cutting edge 9 is provided in the bottom plate 81. The bottom plate 81 includes a flat bottom surface 89 connected to the cutting edge 9. The bottom surface 89 is a bottom surface of the bottom plate 81. The bottom surface 89 is a substantially flat surface.

[0035] The bucket 8 includes a bracket 87 provided in an upper portion of the upper plate 83. The bracket 87 is provided at front and rear positions of the upper plate 83. The bracket 87 is connected to the connecting member 90 and the tilt pin 8T.

[0036] The connecting member 90 includes a plate member 91, a bracket 92 provided on an upper surface of the plate member 91, and a bracket 93 provided on a lower surface of the plate member 91. The bracket 92 is connected to the stem 7 and a second connecting pin 95P. The bracket 93 is provided in an upper portion of the bracket 87 and is connected to the tilt pin 8T and the bracket 87.

[0037] The bucket pin 8B connects the bracket 92 of the link 90 and the front end of the arm 7. The tilt pin 8T connects the bracket 93 of the link 90 and the bracket 87 of the bucket 8. The link 90 and the bucket 8 can rotate about the bucket axis AX3 with respect to the arm 7. The bucket 8 can rotate about the tilt axis AX4 with respect to the link 90.

[0038] The work machine 1 includes a first link 94 rotatably connected to the arm 7 via a first link pin 94P, and a second link 95 rotatably connected to the bracket 92 via the second link pin 95P. A base end of the first link 94 is connected to the arm 7 by the first link pin 94P. A base end of the second link 95 is connected to the bracket 92 by the second link pin 95P. A tip end of the first link 94 and a tip end of the second link 95 are connected to each other by a bucket cylinder top pin 96.

[0039] A tip end of the bucket cylinder 13 is rotatably connected to the tip end of the first link 94 and the tip end of the second link 95 through the bucket cylinder top pin 96. When the bucket cylinder 13 operates to expand and contract, the link 90 rotates around the bucket axis AX3 in combination with the bucket 8.

[0040] The tilt cylinder 14 is connected to a bracket 97 provided in the link 90 and a bracket 88 provided in the bucket 8. A rod of the tilt cylinder 14 is connected to the bracket 97 via a pin. A main body portion of the tilt cylinder 14 is connected to the bracket 88 via a pin. When the tilt cylinder 14 expands and contracts, the bucket 8 rotates around the tilt axis AX4. Furthermore, the connection structure of the tilt cylinder 14 according to this embodiment is only illustrative and is not limited thereto.

[0041] As described above, the bucket 8 rotates around the bucket axis AX3 due to the operation of the bucket cylinder 13. The bucket 8 rotates around the tilt axis AX4 due to the operation of the tilt cylinder 14. When the bucket 8 rotates around the bucket axis AX3, the tilt pin 8T rotates in combination with the bucket 8. [Recording system]

[0042] Next, a detection system 400 of the excavator 100 according to this embodiment will be described. Fig. 4 is a side view schematically illustrating the excavator 100 according to this embodiment. Fig. 5 is a rear view schematically illustrating the excavator 100 according to this embodiment. Fig. 6 is a plan view schematically illustrating the excavator 100 according to this embodiment. Fig. Fig. 7 is a side view schematically showing the bucket 8 according to this embodiment. Fig. Fig. 8 is a front view schematically showing the bucket 8 according to this embodiment.

[0043] As in Fig. 4, Fig. 5 and Fig. 6, the detection system 400 includes a position calculation device 20 that calculates a position of the upper swing body 2 and a work tool angle calculation device 24 that calculates an angle of the work tool 1.

[0044] The position calculation device 20 includes a vehicle body position calculator 21 that detects a position of the upper swing body 2, a posture calculator 22 that detects a posture of the upper swing body 2, and an azimuth calculator 23 that detects an azimuth of the upper bucket body 2.

[0045] The vehicle body position calculator 21 includes a GPS receiver. The vehicle body position calculator 21 is provided in the upper swing body 2. The vehicle body position calculator 21 acquires an absolute position Pg of the upper swing body 2 defined by the global coordinate system. The absolute position Pg of the upper swing body 2 includes coordinate data in the Xg-axis direction, coordinate data in the Yg-axis direction, and coordinate data in the Zg-axis direction.

[0046] A plurality of GPS antennas 21A are provided in the upper swing body 2. Each of the GPS antennas 21A receives electric waves from a GPS satellite and outputs a signal generated based on the received electric waves to the vehicle body position calculator 21. The vehicle body position calculator 21 detects a position Pr where the GPS antenna 21A is provided, which is defined by the global coordinate system based on the signal supplied from the GPS antenna 21A. The vehicle body position calculator 21 detects the absolute position Pg of the upper swing body 2 based on the position Pr where the GPS antenna 21A is provided.

[0047] Two GPS antennas 21A are provided in the vehicle width direction. The vehicle body position calculator 21 detects a position Pra where one of the GPS antennas 21A is provided and a position Prb where the other GPS antenna 21A is provided. The vehicle body position calculator 21A performs calculation processing based on at least one of the position Pra and the position Prb, and calculates the absolute position Pg of the upper swing body 2. In this embodiment, the absolute position Pg of the upper swing body 2 is the position Pra. Further, the absolute position Pg of the upper swing body 2 may be the position Prb, or may be a position between the position Pra and the position Prb.

[0048] The attitude calculator 22 includes an inertial measurement unit (IMU). The attitude calculator 22 is provided in the upper swing body 2. The attitude calculator 22 calculates a tilt angle of the upper swing body 2 with respect to a horizontal plane (XgYg plane) defined by the global coordinate system. The tilt angle of the upper swing body 2 with respect to the horizontal plane includes a roll angle θ1 indicating a tilt angle of the upper swing body 2 in the vehicle width direction and a pitch angle θ2 indicating a tilt angle of the upper swing body 2 in the forward and backward directions.

[0049] The azimuth calculator 23 calculates an azimuth of the upper swing body 2 with respect to a reference azimuth defined by the global coordinate system based on the position Pra where one GPS antenna 21A is provided and the position Prb where the other GPS antenna 21A is provided. The reference azimuth is, for example, north. The azimuth calculator 23 performs calculation processing based on the position Pra and the position Prb, and calculates the azimuth of the upper swing body 2 with respect to the reference azimuth. The azimuth calculator 23 calculates a straight line connecting the position Pra and the position Prb, and calculates the azimuth of the upper swing body 2 with respect to the reference azimuth based on an angle formed between the calculated straight line and the reference azimuth.The azimuth of the upper slewing body 2 with respect to the reference azimuth includes a yaw angle θ3 which indicates an angle made between the reference azimuth and the azimuth of the upper slewing body 2.

[0050] As in Fig. 4, Fig. 7 and Fig. 8, the work implement angle calculating device 24 calculates a boom angle α indicating an inclination angle of the boom 6 with respect to the Zm axis of the vehicle body coordinate system based on a boom stroke detected by the boom stroke sensor 16. The work implement angle calculating device 24 calculates an arm angle β indicating an inclination angle of the arm 7 with respect to the boom 6 based on an arm stroke detected by the arm stroke sensor 17. The work implement angle calculating device 24 calculates a bucket angle γ indicating an inclination angle of the cutting edge 9 of the bucket 8 with respect to the arm 7 based on a bucket stroke detected by the bucket stroke sensor 18.The work implement angle calculation device 24 calculates a tilt angle δ indicating a tilt angle of the bucket 8 with respect to an XmYm plane of the vehicle body coordinate system based on a tilt stroke detected by the tilt stroke sensor 19. The work implement angle calculation device 24 calculates a tilt axis angle ε indicating a tilt angle of the tilt axis AX4 with respect to the XmYm plane of the vehicle body coordinate system based on the boom stroke detected by the boom stroke sensor 16, the arm stroke detected by the arm stroke sensor 17, and the tilt stroke detected by the bucket stroke sensor 18.

[0051] Furthermore, the boom angle α, the arm angle β, the bucket angle γ, the tilt angle δ, and the tilt axis angle ε can be detected without using the lift sensors, for example, by angle sensors provided in the work machine 10. In addition, the angle of the work machine 10 can be optically detected with a stereo camera or a laser scanner, and the boom angle α, the arm angle β, the bucket angle γ, the tilt angle δ, and the tilt axis angle ε can be calculated using the detection result. [Hydraulic system]

[0052] Next, an example of a hydraulic system 300 of the excavator 100 according to this embodiment will be described. Fig. 9 and Fig. 10 are schematic views illustrating an example of the hydraulic system 300 according to this embodiment. The hydraulic cylinder 10, which includes the boom cylinder 11, the arm cylinder 12, the bucket cylinder 13, and the tilt cylinder 14, is driven by the hydraulic system 300. The hydraulic system 300 supplies hydraulic oil to the hydraulic cylinder 10 to drive the hydraulic cylinder 10. The hydraulic system 300 includes a flow rate control valve 25. The flow rate control valve 25 controls the amount of hydraulic oil supplied to the hydraulic cylinder 10 and a direction in which the hydraulic oil flows. The hydraulic cylinder 10 includes a cap-side oil chamber 10A and a rod-side oil chamber 10B. The cap-side oil chamber 10A is a space between a cylinder head cover and a piston. The rod-side oil chamber 10B is a space in which a piston rod is disposed.When hydraulic oil is supplied to the cap-side oil chamber 10A through an oil path 35A, the hydraulic cylinder 10 expands. When hydraulic oil is supplied to the rod-side oil chamber 10B through an oil path 35B, the hydraulic cylinder 10 contracts.

[0053] Fig. 9 is a schematic view illustrating an example of the hydraulic system 300 that operates the arm cylinder 12. The hydraulic system 300 includes a variable displacement main hydraulic pump 31 that supplies the hydraulic oil, a pilot pressure pump 32 that supplies a pilot oil, oil paths 33A and 33B through which the pilot oil flows, pressure sensors 34A and 34B arranged in the oil paths 33A and 33B, control valves 37A and 37B that adjust a pilot pressure acting on the flow rate control valve 25, the actuator 30 that includes the right work implement operating lever 30R and the left work implement operating lever 30L that adjust the pilot pressure with respect to the flow rate control valve 25, and the control device 50. The right work implement operating lever 30R and the left work implement operating lever 30L of the actuator 30 are hydraulic pilot operating devices.

[0054] The hydraulic oil supplied from the main hydraulic pump 31 is supplied to the arm cylinder 12 through the flow rate control valve 25. The flow rate control valve 25 is a spool-type flow control valve that switches a flow direction of the hydraulic oil by moving a rod-shaped spool in the axial direction. When the spool is moved in the axial direction, the supply of hydraulic oil to the cap-side oil chamber 10A of the arm cylinder 12 and the supply of hydraulic oil to the rod-side oil chamber 10B are switched from each other. In addition, when the spool is moved in the axial direction, the supply amount of hydraulic oil per unit time with respect to the arm cylinder 12 is adjusted. When the supply amount of hydraulic oil with respect to the arm cylinder 12 is adjusted, the cylinder speed is adjusted.

[0055] The flow rate control valve 25 is operated by the actuator 30. The pilot oil supplied from the pilot pressure pump 32 is supplied to the actuator 30. Furthermore, pilot oil supplied from the main hydraulic pump 31, the pressure of which is reduced by a pressure reducing valve, may be supplied to the actuator 30. The actuator 30 includes a pilot pressure adjusting valve. The control valves 37A and 37B are operated based on an operation amount of the actuator 30, and a pilot pressure acting on the spool of the flow rate control valve 25 is adjusted. The flow rate control valve 25 is driven by the pilot pressure. When the pilot pressure is adjusted by the actuator 30, the movement amount, a movement speed, and a movement direction of the spool in the axial direction are adjusted.

[0056] The flow rate control valve 25 includes a first pressure-receiving chamber and a second pressure-receiving chamber. When the left work implement operating lever 30L is operated to be tilted to one side compared to a neutral position and the spool is moved by the pilot pressure of the oil path 33A, the hydraulic oil from the main hydraulic pump 31 is supplied to the first pressure-receiving chamber, and the hydraulic oil is supplied to the cap-side oil chamber 10A through the oil path 35A. When the left work implement operating lever 30L is operated to be tilted to the other side compared to the neutral position and the spool is moved by the pilot pressure of the oil path 33B, the hydraulic oil from the main hydraulic pump 31 is supplied to the second pressure-receiving chamber, and the hydraulic oil is supplied to the rod-side oil chamber 10B through the oil path 35B.

[0057] The pressure sensor 34A detects a pilot pressure of the oil path 33A. The pressure sensor 34B detects a pilot pressure of the oil path 33B. A detection signal of the pressure sensor 33A or 33B is output to the control device 50. When the engagement control is performed, the control device 50 outputs a control signal to the control valve 37A or 37B to adjust the pilot pressure.

[0058] A hydraulic system 300 that operates the boom cylinder 11 and the bucket cylinder 13 has the same structure as the hydraulic system 300 that operates the arm cylinder 12. Detailed descriptions of the hydraulic system 300 that operates the boom cylinder 11 and the bucket cylinder 13 are omitted. Furthermore, an engagement control valve that engages a lifting operation of the boom 6 may be connected to the oil path 33A connected to the boom cylinder 11 to perform engagement control with respect to the boom 6.

[0059] Furthermore, the right work implement operating lever 30R and the left work implement operating lever 30L of the operating device 30 do not need to be of the hydraulic pilot type. The right work implement operating lever 30R and the left work implement operating lever 30L may be of the electronic lever type, which outputs an electrical signal to the control device 50 based on an operation amount (tilt angle) of the right work implement operating lever 30R and the left work implement operating lever 30L and directly controls the flow rate control valve 25 based on a control signal from the control device 50.

[0060] Fig. 10 is a view schematically illustrating an example of a hydraulic system 300 that operates the tilt cylinder 14. The hydraulic system 300 includes the flow rate control valve 25 that adjusts the amount of hydraulic oil supplied to the tilt cylinder 14, the control valves 37A and 37B that adjust the pilot pressure acting on the flow rate control valve 25, a control valve 39 disposed between the pilot pressure pump 32 and the operation pedal 30F, the tilt operation lever 30T and the operation pedal 30F of the operation device 30, and the control device 50. In this embodiment, the operation pedal 30F of the operation device 30 is a hydraulic pilot operation device. The tilt operation lever 30T of the operation device 30 is an electronic lever type operation device.The tilting operation lever 30T includes operation buttons provided in the right implement operation lever 30R and the left implement operation lever 30L.

[0061] The operating pedal 30F of the operating device 30 is connected to the pilot pressure pump 32. Furthermore, the operating pedal 30F is connected, through a shuttle valve 36A, to an oil path 38A through which pilot oil flows from the control valve 37A. Furthermore, the operating pedal 30F is connected, through a shuttle valve 36B, to an oil path 38B through which pilot oil supplied from the control valve 37B flows. When the operating pedal 30F is operated, a pressure of an oil path 33A between the operating pedal 30F and the shuttle valve 36A and a pressure of an oil path 33B between the operating pedal 30F and the shuttle valve 36B are adjusted.

[0062] When the tilting operation lever 30T is operated, an operation signal generated by the operation of the tilting operation lever 30T is output to the control device 50. The control device 50 generates a control signal based on the operation signal output from the tilting operation lever 30T to control the control valves 37A and 37B. The control valves 37A and 37B are electromagnetic proportional control valves. The control valve 37A opens and closes the oil path 38A based on the control signal. The control valve 37B opens and closes the oil path 38B based on the control signal.

[0063] When the engagement control with respect to the tilt rotation of the bucket 8 is not executed, the pilot pressure is adjusted based on an operation amount of the operating device 30. When the engagement control with respect to the tilt rotation of the bucket 8 is performed, the control device 50 outputs the control signal to the control valve 37A or 37B to adjust the pilot pressure. [Tax system]

[0064] Next, a control system 200 of the excavator 100 according to this embodiment will be described. Fig. 11 is a functional block diagram illustrating an example of the control system 200 according to this embodiment.

[0065] As in Fig. 11, the control system 200 includes the control device 50 that controls the work machine 1, the position calculation device 20, the work machine angle calculation device 24, the control valves 37 (37A and 37B), and a target construction data generation device 70.

[0066] The position calculation device 20 includes a vehicle body position calculator 21, an attitude calculator 22, and an azimuth calculator 23. The position calculation device 20 detects the absolute position Pg of the upper swing body 2, the attitude of the upper swing body 2, which includes the roll angle θ1 and the pitch angle θ2, and the azimuth of the upper swing body 2, which includes the yaw angle θ3.

[0067] The work implement angle calculating device 24 detects the angle of the work implement 1, which includes the boom angle α, the arm angle β, the bucket angle γ, the tilt angle δ and the tilt axis angle ε.

[0068] The control valves 37 (37A and 37B) adjust the amount of hydraulic oil supplied to the tilt cylinder 14. The control valves 37 operate based on the control signal from the control device 50.

[0069] The target construction data generation device 70 includes a computer system. The target construction data generation device 70 generates target construction data indicating a target topography, which is a target shape of a construction area. The target construction data indicates a three-dimensional target shape obtained after the construction project by the work device 1.

[0070] The target construction data generation device 70 is provided at a location remote from the excavator 100. For example, the target construction data generation device 70 is provided in a facility of a construction management company. Furthermore, the target construction data generation device 70 may be owned by a manufacturing company or a rental company of the excavator 100. The target construction data generation device 70 and the control device 50 can perform wireless communication. The target construction data generated by the target construction data generation device 70 is wirelessly transmitted to the control device 50.

[0071] Furthermore, the target construction data generation device 70 and the control device 50 may be connected with a cable, and the target construction data may be transmitted from the target construction data generation device 70 to the control device 50. Further, the target construction data generation device 70 may include a recording medium that stores the target construction data, and the control device 50 may include a device that can retrieve the target construction data from the recording medium.

[0072] Furthermore, the target construction data generation device 70 may be provided in the excavator 100. The target construction data may be supplied from an external management device that manages the construction project to the target construction data generation device 70 of the excavator 100 in a wired state or wirelessly, and the target construction data generation device 70 may store the supplied target construction data.

[0073] The control device 50 includes a vehicle body position data acquisition unit 51, a work implement angle data acquisition unit 52, a destination point position data calculation unit 53, a target construction topography generation unit 54, a tilt data calculation unit 55, a tilt target topography calculation unit 56, an angle determination unit 57, a work implement control unit 58, a target speed determination unit 59, a storage unit 60, and an input / output unit 61.

[0074] Respective functions of the vehicle body position data acquisition unit 51, the work implement angle data acquisition unit 52, the destination point position data calculation unit 53, the target construction topography generation unit 54, the tilt data calculation unit 55, the tilt target topography calculation unit 56, the angle determination unit 57, the work implement control unit 58, and the target speed determination unit 59 are represented by a processor of the control device 50. A function of the storage unit 60 is represented by the control device 50. A function of the input / output unit 61 is represented by the input / output interface device of the control device 50.The input / output unit 61 is connected to the position calculation device 20, the work implement angle calculation device 24, the control valves 37, and the target construction data generation device 70, and performs data communication with the vehicle body position data acquisition unit 51, the work implement angle data acquisition unit 52, the destination point position data calculation unit 53, the target construction topography generation unit 54, the tilt data calculation unit 55, the tilt target topography calculation unit 56, the angle determination unit 57, the work implement control unit 58, the target speed determination unit 59, and the storage unit 60.

[0075] The storage unit 60 stores parameter data of the excavator 100, which includes the work tool data.

[0076] The vehicle body position data acquisition unit 51 acquires vehicle body position data from the position calculation device 20 through the input / output unit 61. The vehicle body position data includes the absolute position Pg of the upper swing body 2 defined by the global coordinate system, the attitude of the upper swing body 2 including the roll angle θ1 and the pitch angle θ2, and the azimuth of the upper swing body 2 including the yaw angle θ3.

[0077] The work implement angle data acquisition unit 52 acquires the work implement angle data from the work implement angle calculation device 24 through the input / output unit 61. The work implement angle data acquires an angle of the work implement 1 including the boom angle α, the arm angle β, the bucket angle γ, the tilt angle δ, and the tilt axis angle ε.

[0078] The destination point position data calculation unit 53 calculates position data of a destination point RP set in the bucket 8 based on the vehicle body position data acquired by the vehicle body position data acquisition unit 51, the work implement angle data acquired by the work implement angle data acquisition unit 52, and the work implement data stored in the storage unit 60.

[0079] As in Fig. 4 and Fig. As shown in Figure 7, the work tool data includes a boom length L1, an arm length L2, a bucket length L3, a dump length L4, and a bucket width L5. The boom length L1 is a distance between the boom axis AX1 and the arm axis AX2. The arm length L2 is a distance between the arm axis AX2 and the bucket axis AX3. The bucket length L3 is a distance between the bucket axis AX3 and the cutting edge 9 of the bucket 8. The dump length L4 is a distance between the bucket axis AX3 and the dump axis AX4. The bucket width L5 is a distance between the side plate 84 and the side plate 85.

[0080] Fig. 12 is a view schematically illustrating an example of the determination point RP set on the bucket 8 according to this embodiment. As shown in Fig. As shown in Fig. 12, a plurality of determination points RP used in the tilt bucket control are set in the bucket 8. The determination points RP are set on an outer surface of the bucket 8, including the cutting edge 9 and the bottom surface 89 of the bucket 8. The plurality of determination points RP are set on the cutting edge 9 in a bucket width direction. In addition, a plurality of determination points RP are set on the outer surface of the bucket 8, including the bottom surface 89.

[0081] In addition, the work tool data includes bucket outer shape data indicating a shape and dimensions of the bucket 8. The bucket outer shape data includes width data of the bucket 8 indicating the bucket width L5. Furthermore, the bucket outer shape data includes outer shape data of the bucket 8, which includes the outer shape data of the outer surface of the bucket 8. Furthermore, the bucket outer shape data includes coordinate data of the plurality of determination points RP of the bucket 8, with the cutting edge 9 of the bucket 8 set as a reference.

[0082] The destination point position data calculation unit 53 calculates the position data of the destination points RP. The destination point position data calculation unit 53 calculates a relative position of each of the plurality of destination points RP with respect to a reference position P0 of the upper swing body 2 in the vehicle body coordinate system. In addition, the destination point position data calculation unit 53 calculates an absolute position of each of the plurality of destination points RP in the global coordinate system.

[0083] The determination point position data calculation unit 53 can calculate a relative position of each of the plurality of determination points RP of the bucket 8 with respect to the reference position P0 of the upper swing body 2 in the vehicle body coordinate system based on the work implement data including the boom length L1, the arm length L2, the bucket length L3, the tilt length L4, and the bucket outer shape data, as well as the work implement angle data including the boom angle α, the arm angle β, the bucket angle γ, the tilt angle δ, and the tilt axis angle ε. As shown in Fig. As shown in Figure 4, the reference position P0 of the upper slewing body 2 is set to the slewing axis RX of the upper slewing body 2. Furthermore, the reference position P0 of the upper slewing body 2 can be set to the boom axis AX1.

[0084] Furthermore, the destination point position data calculation unit 53 can calculate the absolute position Pa of the bucket 8 in the global coordinate system based on the absolute position Pg of the upper swing body 2 detected by the position calculation device 20 and a relative position between the reference position P0 of the upper swing body 2 and the bucket 8. The absolute position Pg and the relative position with the reference position P0 are known data derived from parameter data of the excavator 100.The destination point position data calculation unit 53 can calculate an absolute position of each of the plurality of destination points RP of the bucket 8 in the global coordinate system based on the vehicle body position data including the absolute position Pg of the upper swing body 2, the relative position between the reference position P0 of the upper swing body 2 and the bucket 8, the work tool data, and the work tool angle data.

[0085] The target construction topography generation unit 54 generates a target construction topography CS indicating a target shape of an excavation object based on the target construction data supplied from the target construction data generation device 70 and stored in the storage unit 60. The target construction data generation device 70 may supply three-dimensional topography data to the target construction topography generation unit 54, or may supply a plurality of line data or a plurality of point data indicating a part of the target shape to the target construction topography generation unit 54 as target construction data. In this embodiment, it is assumed that the target construction data generation device 70 supplies line data indicating a part of the target shape to the target construction topography generation unit 54 as target construction data.

[0086] Fig. 13 is a schematic view illustrating an example of target build data CD according to this embodiment. As shown in Fig. 13, the target construction data CD indicates a target topography of a construction area. The target topography includes a plurality of target construction topographies CS expressed by a triangular polygon. Each of the plurality of target construction topographies CS indicates a target shape of an object to be excavated by the work machine 1. In the target construction data CD, among the target construction topographies CS, a point AP at which a vertical distance to the bucket 8 is the shortest is specified. In addition, in the target construction data CD, a work machine operation plane WP is specified, which passes through the point AP and the bucket 8 and is orthogonal to the bucket axis AX3. The work machine operation plane WP is an operation plane on which the cutting edge 9 of the bucket 8 is moved by an operation of at least one of the boom cylinder 11, the arm cylinder 12, and the bucket cylinder 13, and which is parallel to the XZ plane.The destination point position data calculation unit 53 calculates position data of the destination point RP at which the vertical distance to the point AP of each of the target construction topographies CS is specified as the shortest based on the target construction topography CS and the outer shape data of the bucket 8. When obtaining the destination point RP, data related to at least the width of the bucket 8 can be used. In addition, the destination point RP can be set by an operator.

[0087] The target construction topography generation unit 54 acquires a line LX that is an intersection line between the work implement operation plane WP and the target construction topography CS. In addition, the target construction topography generation unit 54 acquires a line LY that passes through the point AP and is orthogonal to the line LX in the target construction topography CS. The line LY represents an intersection line between a lateral operation plane VP and the target construction topography CS. The lateral operation plane VP is a plane that is orthogonal to the work implement operation plane WP and passes through the point AP.

[0088] Fig. 14 is a schematic view illustrating an example of the target construction topography CS according to this embodiment. The target construction topography generation unit 54 detects the line LX and the line LY, and generates the target construction topography CS indicating the target shape of an excavation target based on the line LX and the line LY. In a case of excavating the target construction topography CS by the bucket 8, the controller 50 moves the bucket 8 along the line LX, that is, an intersection line between the work machine operation plane WP passing through the bucket 8 and the target construction topography CS.

[0089] The tilting data calculation unit 55 calculates, as tilting data, a tilting operation plane TP which passes through the destination point RP of the bucket 8 and is orthogonal to the tilting axis AX4.

[0090] Fig. 15 and Fig. 16 are schematic views illustrating an example of the tilting operation plane TP according to this embodiment. Fig. Figure 15 shows the tilting operation plane TP when the tilting axis AX4 is parallel to the target construction topography CS. Fig. 16 shows the tilting operation plane TP when the tilting axis AX4 is not parallel to the target construction topography CS.

[0091] As in Fig. 15 and Fig. As shown in Figure 16, the tilting operation plane TP represents an operation plane passing through a destination point RPr selected from among multiple destination points RP specified for the bucket 8 and orthogonal to the tilting axis AX4. As the destination point RPr, a destination point RP at which a distance to the target construction topography CS is the shortest is selected from among the multiple destination points RP.

[0092] Fig. 15 and Fig. 16 shows a tilting operation plane TP passing, as an example, through a destination point RPr set on the cutting edge 9. The tilting operation plane TP is an operation plane on which the destination point RPr (the cutting edge 9) of the bucket 8 is moved due to an operation of the tilt cylinder 14. When at least one of the boom cylinder 11, the arm cylinder 12, and the bucket cylinder 13 operates, and the tilt axis angle ε indicating a direction of the tilt axis AX4 varies, an inclination of the tilting operation plane TP also varies.

[0093] As described above, the work implement angle calculation device 24 can calculate the tilt axis angle ε indicating the inclination angle of the tilt axis AX4 with respect to the XY plane. The tilt axis angle ε is acquired by the work implement angle data acquisition unit 52. In addition, position data of the destination point RPr is calculated by the destination point position data calculation unit 53. The tilt data calculation unit 55 can calculate the tilting operation plane TP based on the tilt axis angle ε of the tilt axis AX4 acquired by the work implement angle data acquisition unit 52 and the position of the destination point RPr calculated by the destination point position data calculation unit 53.

[0094] The tipping target topography calculation unit 56 calculates a tipping target topography ST extending in a lateral direction of the bucket 8 in the target construction topography CS based on the position data of the destination point RPr selected from the plurality of destination points RP, the target construction topography CS, and the tipping data. The tipping target topography calculation unit 56 calculates the tipping target topography ST indicated by an intersection point between the target construction topography CS and the tipping operation plane TP. As shown in Fig. 15 and Fig. As shown in Figure 16, the tilting target topography ST is expressed by an intersection line between the target construction topography CS and the tilting operation plane TP. When the tilting axis angle ε, that is, the direction of the tilting axis AX4, varies, the position of the tilting target topography ST changes.

[0095] The angle determination unit 57 determines the tilt angle δ, which indicates an angle of a specific portion of the bucket 8 around the tilt axis AX4, so that the target construction topography CS and the specific portion of the bucket 8 become parallel to each other. In this embodiment, the specific portion of the bucket 8 is the cutting edge 9 of the bucket 8.

[0096] Fig. 17 is a view schematically illustrating a relationship between the cutting edge 9 of the bucket 8 and the target construction topography CS according to this embodiment. Fig. 17 (A) is a view when the bucket 8 is seen from a -Xm side. Fig. 17 (B) is a view when the bucket 8 is seen from the +Ym side. As in Fig. 17, the angle determination unit 57 determines a tilt angle δr indicating an angle of the cutting edge 9 of the bucket 8 around the tilt axis AX4 so that the target construction topography CS and the cutting edge 9 of the bucket 8 become parallel to each other. That is, the angle determination unit 57 determines a tilt rotation angle δr of the cutting edge 9 of the bucket 8 in a tilt rotation direction to make the cutting edge 9 of the bucket 8 parallel to the target construction topography CS.

[0097] In this embodiment, the angle determining unit 57 determines the tilt angle δr of the cutting edge of the bucket 8 so that the tilt target topography ST becomes parallel to the cutting edge 9 of the bucket 8.

[0098] The work implement control unit 58 outputs a control signal for controlling the hydraulic cylinder 10. The work implement control unit 58 controls the tilt cylinder 14 so that the target construction topography CS and the cutting edge 9 of the bucket 8 become parallel to each other, based on the tilt angle δr determined by the angle determination unit 57.

[0099] Furthermore, based on an operation distance Da indicating a distance between the specific destination point RPr of the bucket 8 and the tilt target topography ST, the work machine control unit 58 stops the tilt rotation of the bucket 8 around the tilt axis AX4 so that the bucket 8 does not exceed the target construction topography CS. That is, the work machine control unit 58 stops the bucket 8 in the tilt target topography ST so that the bucket 8 tilting does not exceed the tilt target topography ST.

[0100] If the tilt axis AX4, as shown in Fig. 15, is parallel to the target construction topography CS, the tilt target topography ST and the line LY approximately coincide. Accordingly, the tilt rotation-related intervention control with the tilt target topography ST set as the reference and the tilt rotation-related intervention control with the line LY set as the reference are essentially the same.

[0101] The work implement control unit 58 performs the intervention control with respect to the tilt rotation based on the determination point RPr at which the operation distance Da is the shortest among the plurality of the determination points RP set to the bucket 8. That is, the work implement control unit 58 performs the intervention control with respect to the tilt rotation based on the determination point RPr closest to the tilt target topography ST, the tilt target topography ST, and the operation distance Da such that, among the plurality of determination points RP set to the bucket 8, the determination point RPr closest to the tilt target topography ST does not exceed the tilt target topography ST.

[0102] The target speed determining unit 59 determines a target speed U related to a tilt rotation speed of the bucket 8 based on the operating distance Da. When the operating distance Da is equal to or less than a line distance H, that is, a threshold value, the target speed determining unit 59 limits the tilt rotation speed.

[0103] Fig. 18 is a schematic view illustrating the engagement control with respect to the tilt rotation according to this embodiment. As shown in Fig. 18, the target construction topography CS is specified, and a speed limiting engagement line IL is specified. The speed limiting engagement line IL is parallel to the tilt axis AX4 and is specified at a position that is away from the tilting target topography ST by a line distance H. It is preferable that the line distance H be set so as not to damage an operator's operating sense. When at least a part of the bucket 8 that tilts exceeds the speed limiting engagement line IL and the operating distance Da is equal to or shorter than the line distance H, the work machine control unit 58 limits the tilting rotation speed of the bucket 8. The target speed determining unit 59 determines the target speed U with respect to the tilting rotation speed of the bucket 8 that exceeds the speed limiting engagement line IL. Since in the Fig. 18, a part of the bucket 8 exceeds the speed limiting engagement line IL and the operating distance Da is shorter than the line distance H, the tilt rotation speed is limited.

[0104] The target speed determination unit 59 detects the operating distance Da between the determination point RPr and the tilting target topography ST in a direction parallel to the tilting operation plane TP. In addition, the target speed determination unit 59 detects the target speed U corresponding to the operating distance Da. In a case where it is determined that the operating distance Da is equal to or shorter than the line distance H, the work implement control unit 58 limits the tilting rotation speed.

[0105] Fig. 19 is a view illustrating an example of a relationship between the operating distance Da and the target speed U according to this embodiment. Fig. 19 illustrates an example of a relationship between the operation distance Da and the target speed U for stopping the tilting rotation of the bucket 8 based on the operation distance Da. As shown in Fig. As shown in Figure 19, the target speed U is a speed that is uniformly determined according to the operating distance Da. The target speed U is not set when the operating distance Da is longer than the line distance H, and is set when the operating distance Da is equal to or less than the line distance H. The shorter the operating distance Da becomes, the lower the target speed U becomes. Accordingly, when the operating distance Da becomes 0, the target speed U also becomes 0. Furthermore, in Fig. 19 an approach direction to the target construction topography CS is shown as a negative direction.

[0106] The target speed determination unit 59 calculates a moving speed Vr when the destination point RP moves toward the target construction topography CS (tilting target topography ST) based on the operation amount of the tilting operation lever 30T of the operation device 30. The moving speed Vr is a moving speed of the destination point RPr on a plane parallel to the tilting operation plane TP. The moving speed Vr is calculated with respect to each of the plurality of destination points RP.

[0107] In this embodiment, in a case where the tilt operation lever 30T is operated, the moving speed Vr is calculated based on a current value output from the tilt operation lever 30T. When the tilt operation lever 30T is operated, a current corresponding to an operation amount of the tilt operation lever 30T is output from the tilt operation lever 30T. The storage unit 60 may store a cylinder speed of the tilt cylinder 14 corresponding to the operation amount of the tilt operation lever 30T. Further, the cylinder speed may be obtained by detection by a cylinder stroke sensor. After the cylinder speed of the tilt cylinder 14 is calculated, the target speed determination unit 59 converts the cylinder speed of the tilt cylinder 14 into the moving speed Vr of each of the plurality of determination points RP of the bucket 8 using a Jacobian determinant.

[0108] In a case where it is determined that the operation distance Da is equal to or shorter than the line distance H, the work machine control unit 58 performs speed limitation that limits the moving speed Vr of the destination point RPr with respect to the target construction topography CS to the target speed U. The work machine control unit 58 outputs a control signal to the control valves 37 to suppress the moving speed Vr of the destination point RPr of the bucket 8. The work machine control unit 58 outputs a control signal to the control valves 37 so that the moving speed Vr of the destination point RPr of the bucket 8 becomes the target speed U corresponding to the operation distance Da.Accordingly, the moving speed RP of the destination point RPr of the tilt-rotating bucket 8 becomes slower as the destination point RPr approaches the target construction topography CS (tilt target topography ST), and becomes 0 when the destination point RPr (cutting edge 9) reaches the target construction topography CD. [Angle adjustment method]

[0109] Next, a method for adjusting the tilt angle δ of the bucket 8 according to this embodiment will be described. Fig. 20 is a flowchart showing an example of the method for adjusting the tilt angle δ of the bucket 8 according to this embodiment. Fig. 21 is a schematic view showing an example of the method for adjusting the tilt angle δ of the bucket 8 according to this embodiment.

[0110] The destination point position data calculation unit 53 calculates position data of a destination point RPa specified on the cutting edge 9 and position data of a destination point RPb specified on the cutting edge 9 (step SA10).

[0111] As in Fig. 21, the destination point RPa and the destination point RPb are destination points on both sides in a width direction of the bucket 8 in the cutting edge 9. The destination point position data calculation unit 53 calculates position data of the destination point RPa and position data of the destination point RPb in the vehicle body coordinate system.

[0112] In addition, the destination point position data calculation unit 53 calculates a direction vector Vec_ab connecting the destination point RPa and the destination point RPb based on the position data of the destination point RPa and the position data of the destination point RPb. The direction vector Vec_ab is defined by the following expression (1). VEC_ab=RPb−RPa

[0113] The target construction topography generation unit 54 calculates a normal vector Nd of the target construction topography CS (step SA20).

[0114] The angle determination unit 57 calculates an intersection vector STr between the tilting operation plane TP and the target construction topography CS (step SA30).

[0115] The angle determination unit 57 calculates the tilt angle δr of the cutting edge 9 of the bucket 8 to make the cutting edge 9 of the bucket 8 and the target construction topography CS parallel to each other (step SA40).

[0116] In this embodiment, the angle determination unit 57 performs calculation processing of the following expression (2) to calculate the tilt angle δr. δr=cos−1(STr⋅Vec_ab|STr||Vec_ab|)

[0117] The work implement control unit 58 controls the tilt cylinder 14 based on the tilt angle δr determined by the angle determination unit 57 (step SA50) so that the target construction topography CS and the cutting edge 9 of the bucket 8 become parallel to each other. [Effects]

[0118] As described above, in the tilt bucket according to this embodiment, the tilt angle δr of the cutting edge 9 of the bucket 8 around the tilt axis AX4 is determined in the angle determining unit 57, so that the target construction topography CS and the cutting edge 9 of the bucket 8 become parallel to each other due to a relative angle of the cutting edge 9 of the bucket 8 with respect to the target construction topography CS. The work implement control unit 58 controls the tilt cylinder 14, which rotates the bucket 8 around the tilt axis AX4 based on the tilt angle δr determined by the angle determining unit 57. Consequently, it is possible to make the cutting edge 9 of the bucket 8 and the target construction topography CS parallel to each other in the tilt rotation direction. Accordingly, the workload for an operator of the excavator 1 during construction is reduced, and a high-quality construction result that does not depend on the operator's skill is obtained. Second embodiment

[0119] A second embodiment will be described. In the following description, the same components or equivalent components are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0120] Fig. 22 and Fig. 23 are views schematically illustrating an example of operation of the working machine 1 according to this embodiment. Fig. 22 and Fig. 23 illustrates an example in which the construction work is carried out based on a sloped target construction topography CS using the work tool 1 including the dump bucket 8.

[0121] As in Fig. 22, in some cases, it is desirable to carry out a construction project while moving the arm 7 in a state in which the cutting edge 9 of the bucket 8 and the target construction topography CS are caused to correspond to each other by making the cutting edge 9 and the target construction topography CS parallel to each other. In addition, as shown in Fig. 23, in some cases, it is desirable to carry out construction while moving the arm 7 in a state in which the bottom surface 89 and the target construction topography CS are caused to correspond to each other by making the bottom surface 89 of the bucket 8 and the target construction topography CS parallel to each other.

[0122] In this embodiment, an example will be described in which the work machine control unit 58 controls at least one of the tilt cylinder 14 and the bucket cylinder 13 so as to maintain parallelism between at least one of the cutting edge 9 of the bucket 8 and the ground surface 89 and the target construction topography CS in a state where the arm 7 is working.

[0123] Fig. 24 is a flowchart showing an example of a method for adjusting an angle of the bucket 8 according to this embodiment. Fig. 25 and Fig. 26 are schematic views illustrating an example of the method for adjusting the angle of the bucket 8 according to this embodiment. Fig. 25 schematically shows an example of the method for adjusting the angle of the bucket 8 when the cutting edge 9 of the bucket 8 and the target construction topography CS are made parallel to each other. Fig. 26 schematically illustrates an example of the method for adjusting the angle of the bucket 8 when the bottom surface 89 of the bucket 8 and the target construction topography CS are made parallel to each other.

[0124] In the following description, the cutting edge 9 and the bottom surface 89 of the bucket 8 are appropriately referred to collectively as a specific portion of the bucket 8.

[0125] The destination point position data calculation unit 53 calculates position data of a destination point RPa specified on the cutting edge 9, position data of a destination point RPb specified on the cutting edge 9, and position data of a destination point RPc specified on the bottom surface 89 (step SB10).

[0126] As in Fig. 25, the destination point RPa and the destination point RPb are destination points on both sides in a width direction of the bucket 8 in the cutting edge 9. The destination point position data calculation unit 53 calculates position data of the destination point RPa and position data of the destination point RPb in the vehicle body coordinate system.

[0127] As in Fig. 26, the determination point RPc is a determination point of a part of the bottom surface 89 that is flat. In a width direction of the bucket 8, the coordinates of the determination point RPa and the coordinates of the determination point RPc are equal to each other. In this embodiment, the determination point RPa is specified at one end of the bottom plate 81, and the determination point RPc is specified at the other end of the bottom plate 81.

[0128] In addition, the destination point position data calculation unit 53 calculates a direction vector Vec_ab connecting the destination point RPa and the destination point RPb based on the position data of the destination point RPa and the position data of the destination point RPb.

[0129] In addition, the destination point position data calculation unit 53 calculates a direction vector Vec_ac connecting the destination point RPa and the destination point RPc based on the position data of the destination point RPa and the position data of the destination point RPc.

[0130] In addition, the destination point position data calculation unit 53 calculates a normal vector Vec_tilt of the tilt axis AX4.

[0131] The angle determination unit 57 calculates a target normal vector Nref of the specific portion of the bucket 8 that is parallel to the target construction topography CS (step SB20).

[0132] For example, in a case where the target construction topography CS and the cutting edge 9 of the bucket 8 are formed to be parallel to each other, as shown in Fig. 25, the angle determination unit 57 calculates a target normal vector Nref of the cutting edge 9 of the bucket 8, which is orthogonal to the direction vector Vec_ab of the cutting edge 9 of the bucket 8. The target normal vector Nref of the cutting edge 9 of the bucket 8 is specified to be orthogonal to the direction vector Vec_ab of the cutting edge 9 of the bucket 8 on the tilting operation plane TP. The target normal vector Nref of the cutting edge 9 of the bucket 8 is also orthogonal to the normal vector Vec_tilt of the tilt axis AX4.

[0133] In a case where the target construction topography CS and the bottom surface 89 of the bucket 8 are made parallel to each other, as shown in Fig.26, the angle determination unit 57 calculates a target normal vector Nref of the bottom surface 89 of the bucket 8, which is orthogonal to the direction vector Vec_ac of the bottom surface 89 of the bucket 8. The bottom surface 89 is a substantially flat surface. Accordingly, the target normal vector Nref of the bottom surface 89 of the bucket 8 is uniquely determined.

[0134] The direction vector Vec_ab is given by the above-described expression (1). The direction vector Vec_ac is given by the following expression (3). Vec_ac=RPc−RPa

[0135] The target normal vector Nref of the cutting edge 9 of the bucket 8 is given by the following expression (4). Nref(blade edge)=Vec_ab×Vec_tilt

[0136] The target normal vector Nref of the bottom surface 89 of the bucket 8 is given by the following expression (5). Nref(floor surface)=Vec_ac×Vec_ab

[0137] The target construction topography generation unit 54 calculates a normal vector Nd of the target construction topography CS (step SB30).

[0138] The angle detection unit 57 calculates an evaluation function Q (step SB40).

[0139] The evaluation function Q is the sum of an evaluation function Q1, which indicates a parallelism error between the target normal vector Nref and the normal vector Nd, and an evaluation function Q2, which indicates a distance Da between the cutting edge 9 and the target construction topography CS. That is, the following expressions (6), (7), and (8) hold. Q1=1−Nref⋅Nd Q2=Da Q=Q1+Q2

[0140] In expression (6), a state in which the target normal vector Nref and the normal vector Nd are parallel to each other is a state in which an inner product thereof is 1. That is, the following expression (9) holds. Nref⋅Nd=1

[0141] Furthermore, in a case where it is not necessary to bring the bucket 8 into contact with the target construction topography CS, Q in expression (8) may be Q1.

[0142] The angle detection unit 57 performs calculation processing by a predetermined numerical value calculation method so that the evaluation function Q of (8) becomes minimal. For example, a Newton method, a Powel method, a Simplex method, and the like can be used in the calculation processing.

[0143] The angle detection unit 57 determines whether the evaluation function Q becomes minimal (step SB50). That is, the angle detection unit 57 performs calculation processing by a predetermined numerical operation method and determines whether the evaluation function becomes substantially 0 or not.

[0144] In step SB50, in a case where it is determined that the evaluation function Q is a minimum (step SB50: Yes), the angle detection unit 57 calculates a tilt angle δr and a bucket angle γr of the specific portion of the bucket 8 to make the specific portion of the bucket 8 and the target construction topography CS parallel to each other (step SB60). That is, the angle detection unit 57 determines the tilt angle δr and the bucket angle γr at which the evaluation function Q becomes a minimum.

[0145] The tilt angle δr represents an angle of the specific section of the bucket 8 around the tilt axis AX4 to make the target construction topography CS and the specific section of the bucket 8 parallel to each other. The bucket angle γr represents an angle of the specific section of the bucket 8 around the bucket axis AX3.

[0146] The work machine control unit 58 controls the tilt cylinder 14 and the bucket cylinder 13 based on the tilt angle δr and the bucket angle γr determined by the angle determining unit 57 (step SB70), so that the target construction topography CS and the determined portion of the bucket 8 become parallel to each other.

[0147] In step SB50, in a case where it is determined that the evaluation function Q is not minimum (step SB50: No), the angle detection unit 57 updates the tilt angle δr or the bucket angle γr (step SB80) and returns to the processing in step SB40. Other embodiments

[0148] Furthermore, in the embodiment described above, with respect to the evaluation function Q, a weighting of the evaluation function Q1 and the evaluation function Q2 can be carried out.

[0149] Furthermore, in the above-described embodiments, the construction machine 100 is assumed to be an excavator. The components described in the embodiments are applicable to a construction machine including a work implement different from that of the excavator.

[0150] Furthermore, in the above-described embodiments, the upper swing body 2 may swing by hydraulic pressure or may swing by a force generated by an electric actuator. Additionally, the working device 1 may operate by a force generated by an electric actuator instead of the hydraulic cylinder 10. List of reference symbols 1 WORKING DEVICE 2 UPPER SWIVEL BODY 3 LOWER DRIVING BODY 3C Track 4 DRIVER'S COMPARTMENT 5 ENGINE ROOM 6 booms 7 STEM 8 spoons 8B Spoon Pin 8T tilt pin 9 CUTTING EDGE 10 HYDRAULIC CYLINDER 10A CAP-SIDE OIL CHAMBER 10B ROD-SIDE OIL CHAMBER 11 BOOM CYLINDERS 12 stem cylinders 13 bucket cylinders 14 tilt cylinders 16 BOOM LIFT SENSOR 17 Stick stroke sensor 18 BUCKET LIFT SENSOR 19 Tilt stroke sensor 20 POSITION CALCULATION DEVICE 21 VEHICLE BODY POSITION CALCULATOR 22 POSTURE CALCULATORS 23 AZIMUTH CALCULATOR 24 WORKING EQUIPMENT ANGLE CALCULATION DEVICE 25 FLOW RATE CONTROL VALVE 30 ACTUATOR 30F OPERATING PEDAL 30L LEFT WORKING EQUIPMENT CONTROL LEVER 30R RIGHT WORKING EQUIPMENT CONTROL LEVER 30T TILT CONTROL LEVER 31 MAIN HYDRAULIC PUMP 32 Pilot pressure pump 33A, 33B OIL TRAIL 34A, 34B PRESSURE SENSOR 35A, 35B OIL TRAIL 36A, 36B SHIFT VALVE 37A, 37B CONTROL VALVE 38A, 38B OIL TRAIL 50 CONTROL DEVICE 51 VEHICLE BODY POSITION DATA ACQUISITION UNIT 52 WORKING EQUIPMENT ANGLE DATA ACQUISITION UNIT 53 Destination point position data calculation unit 54 Target Autograph Generation Unit 55 Tilt Data Calculation Unit 56 TILT TARGET TOPOGRAPHY CALCULATION UNIT 57 ANGLE DETERMINATION UNIT 58 WORK EQUIPMENT CONTROL UNIT 59 TARGET SPEED DETERMINATION UNIT 60 STORAGE UNIT 61 INPUT / OUTPUT UNIT 70 TARGET BUILDING DATA GENERATING DEVICE 81 LOWER PLATE 82 REAR PLATE 83 UPPER PLATE 84 SIDE PANEL 85 SIDE PANEL 86 OPENING 87 BRACKET 88 BRACKET 89 FLOOR AREA 90 CONNECTING ELEMENT 91 PLATE ELEMENT 92 BRACKET 93 BRACKET 94 FIRST CONNECTING ELEMENT 94P FIRST CONNECTING PIN 95 SECOND CONNECTING ELEMENT 95P SECOND CONNECTING PIN 96 Spoon cylinder top pin 97 BRACKET 100 EXCAVATORS (CONSTRUCTION MACHINERY) 200 CONTROL SYSTEM 300 HYDRAULIC SYSTEM 400 RECORDING SYSTEM AP POINT AX1 boom axle AX2 STICK AXLE AX3 BUCKET AXLE AX4 TILT AXIS CD TARGET CONSTRUCTION DATA CS TARGET BUILDING AUTOGRAPH Since OPERATION DISTANCE L1 BOOM LENGTH L2 STEM LENGTH L3 Spoon length L4 TILTING LENGTH L5 BUCKET WIDTH LX LINE LY LINE RP DETERMINATION POINT RX SWIVEL AXIS ST TILTING TARGET TOPOGRAPHY TP TILT OPERATING LEVEL α BOOM ANGLE β STEM ANGLE γ spoon angle δ TILT ANGLE ε Tilting axis angle θ1 ROLL ANGLE θ2 ANGLE OF INCLINATION θ3 Yaw Angle

Claims

[1] A control system (200) for a construction machine (100) provided with a work implement (1) comprising an arm (7) and a bucket (8), the bucket (8) being configured to rotate about each of a bucket axis (AX3) and a tilt axis (AX4) orthogonal to the bucket axis (AX3) with respect to the arm (7), and the bucket (8) having designation points (RP) defined on an outer surface, the designation points (RP) including at least a first designation point (RPa) and a second designation point (RPb) specified on both sides in a width direction of the bucket (8) at the cutting edge (9) thereof, the control system comprising: a destination point position data calculation unit (53) configured to calculate position data of the destination points (RPa, RPb) and a direction vector (Vec_ab) based on the position data of the first and second destination points (RPa, RPb), the direction vector (Vec_ab) connecting the first destination point (RPa) and the second destination point (RPb); an angle determination unit (57) configured to calculate an intersection vector (STr) between a tilting operation plane (TP) passing through at least one of the determination points (RP) and being orthogonal to the tilting axis (AX4) and a target construction topography (CS) indicating a target shape of an excavation object, and to determine a tilting angle (δ) based on the direction vector (Vec_ab) and the intersection vector (STr) indicating an angle of a specific portion of the bucket (8) around the tilting axis (AX4) so that the target construction topography (CS) and the specific portion of the bucket (8) become parallel to each other, and a work implement control unit (58) configured to control a tilt cylinder (14) configured to rotate the bucket (8) about the tilt axis (AX4) on the basis of the tilt angle (δ) determined by the angle determining unit (57). [2] Control system for a construction machine (100) according to claim 1, wherein the angle determining unit (57) is arranged to determine a bucket angle (γ) which indicates an angle of the specific portion of the bucket (8) around the bucket axis (AX3) so that the target construction topography (CS) and the specific portion of the bucket (8) become parallel to each other, and the work implement control unit (58) is configured to control the tilt cylinder (14) and a bucket cylinder (13) configured to rotate the bucket (8) about the bucket axis (AX3) on the basis of the tilt angle (δ) and the bucket angle (γ) determined by the angle determining unit (57). [3] Control system for a construction machine (100) according to claim 2, wherein the spoon (8) comprises a cutting edge (9) and a flat bottom surface (89) connected to the cutting edge (9), and the specific section comprises the cutting edge (9) and the bottom surface (89). [4] A control system for a construction machine (100) according to claim 2 or 3, wherein the work implement control unit (58) is arranged to control at least one of the tilt cylinder (14) and the bucket cylinder (13) so as to maintain the parallelism between the specific portion of the bucket (8) and the target construction topography (CS) in a state in which the arm (7) is operating. [5] Construction machine (100), comprising: an upper swivel body (2); a lower traveling body (3) arranged to support the upper swing body (2); a working implement (1) comprising a stick (7) and a bucket (8), the working implement (1) being arranged to be supported on the upper swing body (2); and the control system (200) according to one of claims 1 to 4. [6] A control method for a construction machine (100) provided with a work implement (1) comprising an arm (7) and a bucket (8), the bucket (8) being configured to rotate about each of a bucket axis (AX3) and a tilt axis (AX4) orthogonal to the bucket axis (AX3) with respect to the arm (7), and the bucket (8) having designation points (RP) defined on an outer surface, the designation points (RP) including at least a first designation point (RPa) and a second designation point (RPb) specified on both sides in a width direction of the bucket (8) at the cutting edge (9) thereof, the control method comprising: Calculating, by means of a destination point position data calculation unit (53), position data of the destination points (RPa, RPb) and a direction vector (Vec_ab) based on the position data of the first and second destination points (RPa, RPb), the direction vector (Vec_ab) connecting the first destination point (RPa) and the second destination point (RPb); Calculating, by means of an angle determination unit (57), an intersection vector (STr) between a tilting operation plane (TP) passing through at least one of the determination points (RP) and being orthogonal to the tilting axis (AX4), and a target construction topography (CS) indicating a target shape of an excavation object, and determining a tilting angle (δ) based on the direction vector (Vec_ab) and the intersection vector (STr) indicating an angle of a specific portion of the bucket (8) around the tilting axis (AX4), so that the target construction topography (CS) and the specific portion of the bucket (8) become parallel to each other; and Controlling a tilt cylinder (14) configured to rotate the bucket (8) about the tilt axis (AX4) on the basis of the determined tilt angle (δ).

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