US20240337089A1 - Work machine and method for controlling work machine - Google Patents

Work machine and method for controlling work machine Download PDF

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Publication number
US20240337089A1
US20240337089A1 US18/681,971 US202218681971A US2024337089A1 US 20240337089 A1 US20240337089 A1 US 20240337089A1 US 202218681971 A US202218681971 A US 202218681971A US 2024337089 A1 US2024337089 A1 US 2024337089A1
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US
United States
Prior art keywords
vehicle body
work implement
posture
height
work
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
US18/681,971
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English (en)
Inventor
Takuya Sonoda
Yoshihide Nakae
Takashi Maeda
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Komatsu Ltd
Original Assignee
Komatsu Ltd
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Filing date
Publication date
Application filed by Komatsu Ltd filed Critical Komatsu Ltd
Assigned to KOMATSU LTD. reassignment KOMATSU LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MAEDA, TAKASHI, SONODA, Takuya, NAKAE, YOSHIHIDE
Publication of US20240337089A1 publication Critical patent/US20240337089A1/en
Pending legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/76—Graders, bulldozers, or the like with scraper plates or ploughshare-like elements; Levelling scarifying devices
    • E02F3/80—Component parts
    • E02F3/84—Drives or control devices therefor, e.g. hydraulic drive systems
    • E02F3/844—Drives or control devices therefor, e.g. hydraulic drive systems for positioning the blade, e.g. hydraulically
    • E02F3/847—Drives or control devices therefor, e.g. hydraulic drive systems for positioning the blade, e.g. hydraulically using electromagnetic, optical or acoustic beams to determine the blade position, e.g. laser beams
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/76—Graders, bulldozers, or the like with scraper plates or ploughshare-like elements; Levelling scarifying devices
    • E02F3/80—Component parts
    • E02F3/84—Drives or control devices therefor, e.g. hydraulic drive systems
    • E02F3/841—Devices for controlling and guiding the whole machine, e.g. by feeler elements and reference lines placed exteriorly of the machine
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/2004—Control mechanisms, e.g. control levers
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/2025—Particular purposes of control systems not otherwise provided for
    • E02F9/2041—Automatic repositioning of implements, i.e. memorising determined positions of the implement
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2203—Arrangements for controlling the attitude of actuators, e.g. speed, floating function

Definitions

  • the present invention relates to a work machine and a method for controlling a work machine.
  • a work machine includes a vehicle body, a work implement, and an actuator.
  • the actuator is, for example, a hydraulic cylinder.
  • the actuator is driven in response to an operation by an operator, thereby causing the work implement to move.
  • a motor grader includes a blade as the work implement.
  • the motor grader includes a tandem drive and a frame as the vehicle body. The blade is supported by the frame.
  • the frame supports a front wheel so that the front wheel is rotatable.
  • the tandem drive supports a rear wheel. The operator operates an operating lever of the work implement, thereby causing the blade to move up and down.
  • a controller calculates a change in height of the blade from a relative rotation angle between the frame and the tandem drive. The controller causes the blade to move up and down according to the change in height of the blade. As a result, the blade is maintained at a predetermined height.
  • An object of the present invention is to accurately maintain a work implement at a target height even when a work machine travels over a ground with undulations.
  • One aspect of the present invention is a work machine that includes a vehicle body, a work implement, an actuator, a vehicle body sensor, a work implement sensor, and a controller.
  • the work implement is supported so as to be movable with respect to the vehicle body.
  • the actuator is connected to the work implement.
  • the actuator causes the work implement to move.
  • the vehicle body sensor detects vehicle body posture data indicative of a posture of the vehicle body.
  • the work implement sensor detects work implement posture data indicative of a posture of the work implement.
  • the controller acquires the vehicle body posture data.
  • the controller acquires the work implement posture data.
  • the controller calculates a height of the work implement in a gravity direction from a reference point of the vehicle body based on the vehicle body posture data and the work implement posture data.
  • the controller controls the actuator so that the height of the work implement in the gravity direction is maintained even when the posture of the vehicle body changes.
  • the work machine includes a vehicle body, a work implement, and an actuator.
  • the work implement is supported so as to be movable with respect to the vehicle body.
  • the actuator is connected to the work implement.
  • the actuator causes the work implement to move.
  • the method includes acquiring vehicle body posture data indicative of a posture of the vehicle body, acquiring work implement posture data indicative of a posture of the work implement, calculating a height of the work implement in a gravity direction from a reference point of the vehicle body based on the vehicle body posture data and the work implement posture data, and controlling the actuator so that the height of the work implement in the gravity direction is maintained even when the posture of the vehicle body changes.
  • the height of the work implement in the gravity direction is maintained even when the posture of the vehicle body changes. Therefore, even when the work machine travels over a ground with undulations, the height of the work implement is accurately maintained.
  • FIG. 1 is a side view of a work machine according to an embodiment.
  • FIG. 2 is a perspective view of a front part of the work machine.
  • FIG. 3 is a schematic diagram illustrating a drive system and a control system of the work machine.
  • FIG. 4 is a schematic rear view of the work machine illustrating a posture of a work implement.
  • FIG. 5 is a schematic plan view of the work machine illustrating a posture of the work implement.
  • FIG. 6 is a schematic enlarged side view of the work machine illustrating a posture of the work implement.
  • FIG. 7 is a schematic plan view of the work machine illustrating a posture of the work implement.
  • FIG. 8 is a schematic plan view of the work machine illustrating a posture of the work implement.
  • FIG. 9 is a schematic side view illustrating a vehicle body coordinate system of the work machine.
  • FIG. 10 is a schematic rear view illustrating the vehicle body coordinate system of the work machine.
  • FIG. 11 is a flowchart illustrating processes of an automatic control of the work implement.
  • FIG. 12 is a schematic side view illustrating the vehicle body coordinate system of the work machine.
  • FIG. 1 is a side view of a work machine 1 according to the embodiment.
  • FIG. 2 is a perspective view of a front part of the work machine 1 .
  • the work machine 1 according to the present embodiment is a motor grader.
  • the work machine 1 includes a vehicle body 2 and a work implement 3 .
  • the work implement 3 is supported so as to be movable with respect to the vehicle body 2 .
  • the vehicle body 2 includes a vehicle body frame 4 , a tandem drive 5 , front wheels 6 , and rear wheels 7 A and 7 B.
  • the vehicle body frame 4 supports the front wheels 6 and the work implement 3 .
  • the vehicle body frame 4 includes a front frame 11 and a rear frame 12 .
  • the rear frame 12 is connected to the front frame 11 .
  • the front frame 11 is able to articulate to the left and right with respect to the rear frame 12 .
  • the front, rear, left, and right directions mean the front, rear, left, and right directions of the vehicle body 2 while the articulation angle is zero, that is, while the front frame 11 and the rear frame 12 are straight.
  • a cab 13 and a power compartment 14 are disposed on the rear frame 12 .
  • An unillustrated operator's seat is disposed in the cab 13 .
  • a drive system which will be described later is disposed in the power compartment 14 .
  • the front frame 11 extends forward from the rear frame 12 .
  • the front wheels 6 are attached to the front frame 11 .
  • the tandem drive 5 is connected to the rear frame 12 .
  • the tandem drive 5 supports the rear wheels 7 A and 7 B and drives the rear wheels 7 A and 7 B.
  • the tandem drive 5 includes a rear axis 10 that extends in the left-right direction.
  • the tandem drive 5 supports the rear frame 12 of the vehicle body frame 4 so that the rear frame 12 is swingable about the rear axis 10 .
  • the vehicle body frame 4 swings about the rear axis 10 (see FIG. 9 .)
  • the rear wheels 7 A and 7 B include a pair of first rear wheels 7 A and a pair of second rear wheels 7 B.
  • first rear wheels 7 A In FIG. 1 , only the first rear wheel 7 A at the left side and the second rear wheel 7 B at the left side are illustrated.
  • the second rear wheels 7 B are disposed behind the first rear wheels 7 A.
  • the rear axis 10 is disposed between the first rear wheels 7 A and the second rear wheels 7 B.
  • the rear axis 10 serves as the center of swing of the vehicle body frame 4 with respect to the tandem drive 5 .
  • the work implement 3 is movably connected to the vehicle body 2 .
  • the work implement 3 includes a supporting member 15 and a blade 16 .
  • the supporting member 15 is movably connected to the vehicle body 2 .
  • the supporting member 15 supports the blade 16 .
  • the supporting member 15 includes a drawbar 17 and a circle 18 .
  • the drawbar 17 and the circle 18 are disposed below the front frame 11 .
  • the drawbar 17 is connected to a shaft support part 19 of the front frame 11 .
  • the shaft support part 19 is disposed at a front part of the front frame 11 .
  • the drawbar 17 extends rearward from the front part of the front frame 11 .
  • the drawbar 17 is supported so as to be swingable at least in the up-down direction and the left-right direction of the vehicle body 2 with respect to the front frame 11 .
  • the shaft support part 19 includes a ball joint.
  • the drawbar 17 is rotatably connected to the front frame 11 via the ball joint.
  • the circle 18 is connected to a rear part of the drawbar 17 .
  • the circle 18 is supported so as to be rotatable with respect to the drawbar 17 .
  • the blade 16 is connected to the circle 18 .
  • the blade 16 is supported by the drawbar 17 via the circle 18 .
  • the blade 16 is supported by the circle 18 so as to be rotatable about a tilt shaft 21 .
  • the tilt shaft 21 extends in the left-right direction.
  • the blade 16 is supported by the circle 18 so as to be slidable in the left-right direction.
  • the work machine 1 includes a plurality of actuators 22 to 27 for changing the posture of the work implement 3 .
  • the plurality of actuators 22 to 27 include a plurality of hydraulic cylinders 22 to 26 .
  • the plurality of hydraulic cylinders 22 to 26 are connected to the work implement 3 .
  • the plurality of hydraulic cylinders 22 to 26 extend and contract due to hydraulic pressure.
  • the plurality of hydraulic cylinders 22 to 26 extend and contract, thereby changing the posture of the work implement 3 with respect to the vehicle body 2 .
  • the extension and contraction of the hydraulic cylinders is referred to as a “stroke motion.”
  • the plurality of hydraulic cylinders 22 to 26 include a left lift cylinder 22 , a right lift cylinder 23 , a drawbar shift cylinder 24 , a blade tilt cylinder 25 , and a blade shift cylinder 26 .
  • the left lift cylinder 22 and the right lift cylinder 23 are disposed apart from each other in the left-right direction.
  • the left lift cylinder 22 is connected to a left part of the drawbar 17 .
  • the right lift cylinder 23 is connected to a right part of the drawbar 17 .
  • the left lift cylinder 22 and the right lift cylinder 23 are connected to the drawbar 17 so as to be swingable to the left and right.
  • the left lift cylinder 22 and the right lift cylinder 23 are connected so as to be swingable to the left and right with respect to the front frame 11 .
  • the left lift cylinder 22 and the right lift cylinder 23 are connected to the front frame 11 via a lifter bracket 29 .
  • the lifter bracket 29 is connected to the front frame 11 .
  • the lifter bracket 29 supports the left lift cylinder 22 and the right lift cylinder 23 so that the left lift cylinder 22 and the right lift cylinder 23 are swingable to the left and right. Due to the stroke motions of the left lift cylinder 22 and the right lift cylinder 23 , the drawbar 17 swings up and down about the shaft support part 19 . As a result, the blade 16 moves up and down.
  • the drawbar shift cylinder 24 is connected to the drawbar 17 and the front frame 11 .
  • the drawbar shift cylinder 24 is connected to the front frame 11 via the lifter bracket 29 .
  • the drawbar shift cylinder 24 is connected so as to be swingable with respect to the front frame 11 .
  • the drawbar shift cylinder 24 is connected so as to be swingable with respect to the drawbar 17 .
  • the drawbar shift cylinder 24 extends diagonally downward from the front frame 11 toward the drawbar 17 .
  • the drawbar shift cylinder 24 extends to the left and right from one side to the opposite side of the front frame 11 .
  • the drawbar 17 swings to the left and right about the shaft support part 19 due to the stroke motion of the drawbar shift cylinder 24 .
  • the blade tilt cylinder 25 is connected to the circle 18 and the blade 16 .
  • the blade 16 rotates about the tilt shaft 21 due to the stroke motion of the blade tilt cylinder 25 .
  • the blade shift cylinder 26 is connected to the circle 18 and the blade 16 .
  • the blade 16 slides to the left and right with respect to the circle 18 due to the stroke motion of the blade shift cylinder 26 .
  • the plurality of actuators 22 to 27 include a rotary actuator 27 .
  • the rotary actuator 27 is connected to the drawbar 17 and the circle 18 .
  • the rotary actuator 27 causes the circle 18 to rotate with respect to the drawbar 17 .
  • the blade 16 rotates about a rotation axis that extends in the up-down direction.
  • FIG. 3 is a schematic diagram illustrating a drive system 8 and a control system 9 of the work machine 1 .
  • the work machine 1 includes a drive source 31 , a hydraulic pump 32 , a power transmission device 33 , and a control valve 34 .
  • the drive source 31 is, for example, an internal combustion engine. Alternatively, the drive source 31 may be an electric motor or a hybrid of an internal combustion engine and an electric motor.
  • the hydraulic pump 32 is driven by the drive source 31 to discharge hydraulic fluid.
  • the control valve 34 is connected to the hydraulic pump 32 and the plurality of hydraulic cylinders 22 to 26 through a hydraulic circuit.
  • the control valve 34 includes a plurality of valves respectively connected to the plurality of hydraulic cylinders 22 to 26 .
  • the control valve 34 controls the flow rate of hydraulic fluid supplied from the hydraulic pump 32 to the plurality of hydraulic cylinders 22 to 26 .
  • the rotary actuator 27 is a hydraulic motor.
  • the control valve 34 is connected to the hydraulic pump 32 and the rotary actuator 27 through a hydraulic circuit.
  • the control valve 34 controls the flow rate of hydraulic fluid supplied from the hydraulic pump 32 to the rotary actuator 27 .
  • the rotary actuator 27 may be an electric motor.
  • the power transmission device 33 transmits the driving force from the drive source 31 to the rear wheels 7 A and 7 B.
  • the power transmission device 33 may include a torque converter and/or a plurality of speed change gears.
  • the power transmission device 33 may be a transmission such as a hydraulic static transmission (HST) or a hydraulic mechanical transmission (HMT).
  • the work machine 1 includes an operating device 35 and a controller 36 .
  • the operating device 35 is operable by an operator for changing the posture of the work implement 3 .
  • the posture of the work implement 3 indicates a position and an orientation of the blade 16 with respect to the vehicle body 2 .
  • FIG. 4 is a schematic rear view of the work machine 1 illustrating the posture of the work implement 3 . As illustrated in FIG. 4 , the height of a left end portion 161 and the height of a right end portion 162 of the blade 16 are changed according to an operation of the operating device 35 .
  • FIG. 5 is a schematic plan view of the work machine 1 illustrating the posture of the work implement 3 .
  • the yaw angle ⁇ 1 of the drawbar 17 is a tilt angle of the drawbar 17 in the left-right direction with respect to the front-rear direction of the vehicle body 2 .
  • the yaw angle ⁇ 1 of the drawbar 17 may be a tilt angle of the drawbar 17 in the left-right direction with respect to the front-rear direction of the front frame 11 .
  • the position of the blade 16 in the left-right direction changes according to the yaw angle ⁇ 1 of the drawbar 17 .
  • FIG. 6 is a schematic side view of the work machine 1 illustrating the posture of the work implement 3 .
  • the pitch angle ⁇ 2 of the drawbar 17 is a tilt angle of the drawbar 17 in the up-down direction with respect to the front-rear direction of the vehicle body 2 .
  • the roll angle ⁇ 3 of the drawbar 17 is a tilt angle of the drawbar 17 about a roll axis A 1 that extends in the front-rear direction of the vehicle body 2 .
  • FIG. 7 is a schematic plan view of the work machine 1 illustrating the posture of the work implement 3 .
  • the rotation angle ⁇ 4 of the circle 18 is the rotation angle ⁇ 4 of the circle 18 with respect to the front-rear direction of the vehicle body 2 .
  • the tilt angle ⁇ 5 of the blade 16 is a tilt angle of the blade 16 about the tilt shaft 21 that extends in the left-right direction.
  • FIG. 8 is a schematic plan view of the work machine 1 illustrating the posture of the work implement 3 .
  • the shift amount W 1 of the blade 16 is an amount by which the blade 16 slides in the left-right direction with respect to the circle 18 .
  • the operating device 35 includes a plurality of operating members 41 to 46 .
  • the plurality of operating members 41 to 46 are provided respectively corresponding to the left lift cylinder 22 , the right lift cylinder 23 , the drawbar shift cylinder 24 , the blade tilt cylinder 25 , the blade shift cylinder 26 , and the rotary actuator 27 .
  • the plurality of operating members 41 to 46 include a left lift lever 41 , a right lift lever 42 , a drawbar shift lever 43 , a rotation lever 44 , a blade tilt lever 45 , and a blade shift lever 46 .
  • the left lift cylinder 22 extends and contracts according to an operation of the left lift lever 41 .
  • the right lift cylinder 23 extends and contracts according to an operation of the right lift lever 42 .
  • the drawbar shift cylinder 24 extends and contracts according to an operation of the drawbar shift lever 43 .
  • the rotary actuator 27 rotates according to an operation of the rotation lever 44 .
  • the blade tilt cylinder 25 extends and contracts according to an operation of the blade tilt lever 45 .
  • the blade shift cylinder 26 extends and contracts according to an operation of the blade shift lever 46 .
  • Each of the plurality of operating members 41 to 46 outputs a signal indicative of the operation by the operator for each of the operating member 41 to 46 .
  • the controller 36 controls the drive source 31 and the power transmission device 33 , thereby causing the work machine 1 to travel. Further, the controller 36 controls the hydraulic pump 32 and the control valve 34 , thereby causing the work implement 3 to move.
  • the controller 36 includes a processor 37 and a storage device 38 .
  • the processor 37 is, for example, a CPU and executes a program for controlling the work machine 1 .
  • the storage device 38 includes a memory such as a RAM or a ROM, and an auxiliary storage device such as an SSD or an HDD.
  • the storage device 38 stores programs and data for controlling the work machine 1 .
  • the work machine 1 includes a work implement sensor 48 for detecting the posture of the work implement 3 described above.
  • the work implement sensor 48 includes a plurality of sensors S 1 to S 8 .
  • the plurality of sensors S 1 to S 8 are, for example, magnetic sensors.
  • the plurality of sensors S 1 to S 8 may be sensors of another type such as an optical sensor.
  • the plurality of sensors S 1 to S 5 detect stroke lengths of the plurality of hydraulic cylinders 22 to 26 described above.
  • the plurality of sensors S 1 to S 5 include a left lift sensor S 1 , a right lift sensor S 2 , a drawbar shift sensor S 3 , a blade tilt sensor S 4 , and a blade shift sensor S 5 .
  • the left lift sensor S 1 detects a stroke length of the left lift cylinder 22 .
  • the right lift sensor S 2 detects a stroke length of the right lift cylinder 23 .
  • the drawbar shift sensor S 3 detects a stroke length of the drawbar shift cylinder 24 .
  • the blade tilt sensor S 4 detects a stroke length of the blade tilt cylinder 25 .
  • the blade shift sensor S 5 detects a stroke length of the blade shift cylinder 26 .
  • the plurality of sensors S 1 to S 8 include a rotation sensor S 6 .
  • the rotation sensor S 6 detects the rotation angle ⁇ 4 of the circle 18 .
  • the plurality of sensors S 1 to S 8 output signals indicative of the stroke lengths and the rotation angle ⁇ 4 detected by the respective sensors.
  • the plurality of sensors S 1 to S 8 include a left cylinder angle sensor S 7 and a right cylinder angle sensor S 8 .
  • the left cylinder angle sensor S 7 detects a swing angle of the left lift cylinder 22 in the left-right direction with respect to the lifter bracket 29 .
  • the right cylinder angle sensor S 8 detects a swing angle of the right lift cylinder 23 in the left-right direction with respect to the lifter bracket 29 .
  • a posture of the drawbar 17 with respect to the vehicle body 2 is detected and a posture of the blade 16 with respect to the drawbar 17 is detected. That is, the posture of the blade 16 with respect to the vehicle body 2 is detected by these sensors S 1 to S 8 .
  • the work machine 1 includes a vehicle body sensor 49 .
  • the vehicle body sensor 49 is, for example, an inertial measurement unit (IMU).
  • the vehicle body sensor 49 detects vehicle body posture data indicative of a posture of the vehicle body 2 .
  • the vehicle body posture data includes a pitch angle and a roll angle of the vehicle body 2 .
  • the vehicle body sensor 49 is not limited to the IMU.
  • the vehicle body sensor 49 may be any means that measures the pitch angle and the roll angle of the vehicle body 2 , and may be an inclinometer, for example.
  • the vehicle body sensor 49 is attached to the vehicle body frame 4 . Therefore, as illustrated in FIG. 9 , a pitch angle ⁇ 6 of the vehicle body 2 is a tilt angle of the vehicle body frame 4 in the up-down direction with respect to a horizontal direction. As illustrated in FIG. 10 , a roll angle ⁇ 7 of the vehicle body 2 is a tilt angle of the vehicle body frame 4 in the left-right direction with respect to the horizontal direction.
  • the vehicle body sensor 49 may be attached to another place on the vehicle body 2 where the position relative to the vehicle body frame 4 does not change, instead of the vehicle body frame 4 .
  • the vehicle body sensor 49 may be disposed on any of other places excluding the tandem drive 5 or the drawbar 17 where the position relative to the vehicle body frame 4 changes.
  • the controller 36 acquires work implement posture data indicative of the posture of the work implement 3 with respect to the vehicle body 2 based on a signal from the work implement sensor 48 .
  • the work implement posture data includes the height of the left end portion 161 of the blade 16 , the height of the right end portion 162 , the yaw angle ⁇ 1 of the drawbar 17 , the pitch angle ⁇ 2 , the roll angle ⁇ 3 , the rotation angle ⁇ 4 of the circle 18 , the tilt angle ⁇ 5 of the blade 16 , and the shift amount W 1 of the blade 16 as described above.
  • the controller 36 acquires the vehicle body posture data based on a signal from the vehicle body sensor 49 .
  • the controller 36 controls the plurality of actuators 22 to 27 according to the operations of the plurality of operating members 41 to 46 , thereby changing the posture of the work implement 3 .
  • the controller 36 performs an automatic control of the work implement 3 based on the aforementioned vehicle body posture data and work implement posture data.
  • the controller 36 controls the left lift cylinder 22 and the right lift cylinder 23 so as to maintain the work implement 3 at a target height under the automatic control of the work implement 3 . Processes of the automatic control of the work implement 3 will be described below.
  • FIG. 11 is a flowchart illustrating the processes of the automatic control of the work implement 3 .
  • step S 101 the controller 36 determines whether the operating device 35 is being operated.
  • the controller 36 may determine that the operating device 35 is no longer operated when an operation input on the operating device 35 is not performed for a certain period of time.
  • the controller 36 does not perform the automatic control the work implement 3 . Therefore, the controller 36 controls the plurality of actuators 22 to 27 according to the operations of the plurality of operating members 41 to 46 , thereby changing the posture of the work implement 3 .
  • the process proceeds to step S 102 .
  • step S 102 the controller 36 acquires a current posture of the vehicle body 2 .
  • the controller 36 acquires the current posture of the vehicle body 2 from the vehicle body posture data.
  • step S 103 the controller 36 acquires a current posture of the work implement 3 .
  • the controller 36 acquires the current posture of the work implement 3 from the work implement posture data.
  • step S 104 the controller 36 calculates a current height of the work implement 3 .
  • the controller 36 calculates the height of the work implement 3 based on the vehicle body posture data and the work implement posture data.
  • the height of the work implement 3 is the height of the left end portion 161 and the height of the right end portion 162 of the blade 16 .
  • the height of the work implement 3 means the height in the gravity direction from an origin O 1 taking the origin O 1 of the vehicle body 2 illustrated in FIG. 12 as a reference point.
  • the height of the work implement 3 means the height of the work implement 3 in the gravity direction from a horizontal surface including the origin O 1 of the vehicle body 2 .
  • the origin O 1 of the vehicle body 2 is positioned on the tandem drive 5 .
  • the origin O 1 of the vehicle body 2 is positioned at the center of the rear axis 10 in the left-right direction.
  • a Z 1 axis indicates the gravity direction.
  • An X 1 axis indicates the front-rear direction of the vehicle body 2 that is perpendicular to the gravity direction.
  • a Y 1 axis indicates the left-right direction of the vehicle body 2 that is perpendicular to the gravity direction.
  • the posture of the vehicle body 2 changes about the origin O 1 of the vehicle body 2 .
  • the pitch angle ⁇ 6 of the vehicle body 2 changes about the origin O 1 .
  • the roll angle ⁇ 7 of the vehicle body 2 changes about the origin O 1 .
  • step S 105 the controller 36 determines a target posture of the work implement 3 .
  • the controller 36 calculates the target posture of the work implement 3 so that the height of the work implement 3 is the target height.
  • the controller 36 stores, as the target height, the height of the work implement 3 when it is determined that the operating device 35 is no longer operated.
  • the controller 36 calculates a target pitch angle and a target roll angle of the drawbar 17 so that the height of the work implement 3 is the target height.
  • step S 106 the controller 36 controls at least one of the actuators 22 to 27 so that the height of the work implement 3 is the target height.
  • the controller 36 controls the lift cylinders 22 and 23 and the drawbar shift cylinder 24 so that the pitch angle ⁇ 2 of the drawbar 17 is the target pitch angle and the roll angle ⁇ 3 of the drawbar 17 is the target roll angle.
  • the controller 36 controls the lift cylinders 22 and 23 and the drawbar shift cylinder 24 so that a position of the blade 16 in the left-right direction does not change. That is, in the work machine 1 , due to the extension and contraction of the lift cylinders 22 and 23 , not only the height direction of the blade 16 but also the position of the blade 16 in the left and right direction changes. Therefore, the controller 36 controls the drawbar shift cylinder 24 so as to offset a change in position of the blade 16 in the left-right direction due to the extension and contraction of the lift cylinders 22 and 23 . As a result, the height of the work implement 3 is maintained at the target height and the position of the work implement 3 in the left-right direction is maintained.
  • the controller 36 controls the actuators 22 to 27 so that the work implement 3 is maintained at the target height by repeating the aforementioned processes of steps S 102 to S 106 .
  • the controller 36 ends the automatic control (step S 101 ).
  • the work implement 3 is maintained at the target height of the work implement 3 by the automatic control.
  • the target height is the height in the gravity direction from the origin O 1 of the vehicle body 2 , and the work implement 3 is maintained at the target height of the work implement 3 even when the posture of the vehicle body 2 changes. Therefore, the work implement 3 is accurately maintained at the target height even when the work machine 1 travels on a ground with undulations.
  • the blade 16 ′ depicted with a dashed line indicates the position of the blade 16 when the automatic control is not performed.
  • the blade 16 ′ is raised above the position of the blade 16 illustrated in FIG. 12 , when the front wheels 6 travel over a bump.
  • the blade 16 is maintained at the target height of the work implement 3 in the gravity direction by the automatic control as illustrated in FIG. 9 . Therefore, even if the front wheels 6 travel over a bump, the controller 36 controls the actuators 22 to 27 , thereby causing the blade 16 to be accurately maintained at the target height.
  • the work machine 1 is not limited to a motor grader and may be another work machine such as a bulldozer. In another work machine such as a bulldozer, a position of the origin O 1 can be set according to a structural characteristic of the work machine.
  • the configuration of the work implement 3 is not limited to that of the above embodiment and may be changed.
  • the work implement 3 may include a blade and a lift arm. The lift arm may support the blade and be connected to the vehicle body.
  • the parameters indicative of the posture of the work implement 3 are not limited to those of the above embodiment and may be changed.
  • the plurality of operating members 41 to 46 are not limited to those of the above embodiment and may be changed.
  • the operating member is not limited to a lever and may be another member such as a joystick, a switch, or a touch screen.
  • the plurality of operating members 41 to 46 may directly operate the respective actuators 22 to 27 .
  • the sensor for detecting the posture of the work implement 3 is not limited to that of the above embodiment and may be changed.
  • the sensors S 1 to S 5 may directly detect angles, instead of the stroke lengths.
  • the work implement sensor 48 may include an inertial measurement unit (IMU).
  • the IMU may be mounted on the drawbar 17 .
  • the posture of the drawbar 17 may be detected by the IMU. Either of the left cylinder angle sensor S 7 or the right cylinder angle sensor S 8 may be omitted.
  • the operating device 35 may include an operating member for the automatic control.
  • the controller 36 may start the automatic control according to an operation of the operating member for the automatic control.
  • the controller 36 may end the automatic control according to an operation of the operating member for the automatic control.
  • the controller 36 may store, as the target height, the height of the work implement 3 when the automatic control is started.
  • the controller 36 may temporarily release the automatic control.
  • the controller 36 may temporarily release the automatic control when a difference between the target posture and the current posture of the work implement 3 exceeds a predetermined threshold.
  • the automatic control when the work machine 1 performs work while traveling forward has been described, but the present invention may be applied when the work machine 1 performs work while traveling backward.
  • the origin O of the vehicle body 2 may be a center position between the left and right front wheels 6 .
  • the controller 36 acquires the posture of the work implement 3 when the operating device 35 is not operated for a certain period of time and acquires the height of the work implement 3 at that time as the current height of the work implement 3 .
  • the method for acquiring the current height of the work implement 3 is not limited to this and may be changed.
  • the controller 36 may acquire the posture of the work implement 3 when the operating device such as a push button is operated and acquire the height of the work implement 3 at that time as the current height of the work implement 3 .
  • a switch for increasing or decreasing the acquired height of the work implement 3 by a predetermined amount may be provided.
  • the controller 36 may change the target posture of the work implement 3 according to an operation of the switch. As a result, the target posture of the work implement 3 can be finely adjusted.
  • the work implement is accurately maintained at the target height even when the work machine travels on a ground with undulations.

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  • Engineering & Computer Science (AREA)
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  • Structural Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Operation Control Of Excavators (AREA)
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PCT/JP2022/032445 WO2023067898A1 (ja) 2021-10-22 2022-08-29 作業機械、及び、作業機械を制御するための方法

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JP2024060716A (ja) * 2022-10-20 2024-05-07 株式会社小松製作所 作業機械、及び、作業機械を制御するための方法
JP2025087373A (ja) * 2023-11-29 2025-06-10 株式会社小松製作所 モータグレーダを制御するためのシステムおよび方法

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JPS557506B2 (https=) * 1972-05-12 1980-02-26
JPS5282803A (en) * 1975-12-29 1977-07-11 Komatsu Mfg Co Ltd Device for automatically controlling blade of construction machine
JPH08165677A (ja) * 1994-12-13 1996-06-25 Tamagawa Seiki Co Ltd パワーショベルのバケット位置制御方法及び装置
US6269885B1 (en) * 1999-12-15 2001-08-07 Husco International, Inc. Blade height control system for a motorized grader
JP4669499B2 (ja) * 2007-08-10 2011-04-13 日本中央競馬会 ブレード制御装置
US8141650B2 (en) * 2008-06-24 2012-03-27 Deere & Company Automatic depth correction based on blade pitch
JP6689638B2 (ja) * 2016-03-23 2020-04-28 株式会社小松製作所 モータグレーダの制御方法およびモータグレーダ
JP7236810B2 (ja) * 2018-03-28 2023-03-10 株式会社小松製作所 作業車両の制御システム、方法、及び作業車両

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