US20190338489A1 - Work vehicle and method of controlling work vehicle - Google Patents

Work vehicle and method of controlling work vehicle Download PDF

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Publication number
US20190338489A1
US20190338489A1 US16/476,653 US201816476653A US2019338489A1 US 20190338489 A1 US20190338489 A1 US 20190338489A1 US 201816476653 A US201816476653 A US 201816476653A US 2019338489 A1 US2019338489 A1 US 2019338489A1
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United States
Prior art keywords
bucket
angle
excavation
arm
respect
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Abandoned
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US16/476,653
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English (en)
Inventor
Nobuyoshi YAMANAKA
Toshiaki Kumagai
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Komatsu Ltd
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Komatsu Ltd
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Assigned to KOMATSU LTD. reassignment KOMATSU LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KUMAGAI, TOSHIAKI, YAMANAKA, NOBUYOSHI
Publication of US20190338489A1 publication Critical patent/US20190338489A1/en
Abandoned legal-status Critical Current

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    • 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
    • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
    • E02F3/36—Component parts
    • E02F3/42—Drives for dippers, buckets, dipper-arms or bucket-arms
    • E02F3/43—Control of dipper or bucket position; Control of sequence of drive operations
    • E02F3/431—Control of dipper or bucket position; Control of sequence of drive operations for bucket-arms, front-end loaders, dumpers or the like
    • 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
    • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
    • E02F3/36—Component parts
    • E02F3/42—Drives for dippers, buckets, dipper-arms or bucket-arms
    • E02F3/43—Control of dipper or bucket position; Control of sequence of drive operations
    • E02F3/435—Control of dipper or bucket position; Control of sequence of drive operations for dipper-arms, backhoes or the like
    • E02F3/439—Automatic repositioning of the implement, e.g. automatic dumping, auto-return
    • 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
    • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
    • E02F3/30—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets with a dipper-arm pivoted on a cantilever beam, i.e. boom
    • E02F3/32—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets with a dipper-arm pivoted on a cantilever beam, i.e. boom working downwardly and towards the machine, e.g. with backhoes
    • 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

Definitions

  • the present disclosure relates to a work vehicle.
  • a hydraulic excavator includes a work implement having a boom, an arm and a bucket.
  • an operator needs to move the operation levers for three axes corresponding to the boom, the arm and the bucket so as to control the movement of the bucket.
  • the arm is operated to cause the bucket to dig into soil.
  • the bucket deeply digs into soil, so that the resistance of soil is increased.
  • an operation of manipulating the boom so as to raise the bucket is added. This achieves an appropriate depth of digging by the bucket with respect to the soil.
  • Japanese Patent Laying-Open No. 61-225429 discloses a system of detecting contact between a back surface of a bucket and an excavation surface in order to reduce the resistance of soil during the excavation operation, and automatically correcting the posture of the bucket in order to avoid interference of the back surface of the bucket.
  • Japanese Patent Laying-Open No. 62-189222 discloses a system of measuring the weight of soil contained in a bucket to automatically adjust the depth of digging by the bucket such that the weight of the soil contained in the bucket becomes equal to the weight of the soil that is fully contained in the bucket.
  • An object of the present disclosure is to provide a work vehicle and a method of controlling the work vehicle, by which an efficient excavation operation can be performed in a simple manner without having to carry out a complicated computation during an excavation operation by adjusting the posture of a bucket before the start of excavation.
  • a work vehicle includes: a vehicular body; a work implement including a boom pivotable with respect to the vehicular body, an arm pivotable with respect to the boom, and a bucket pivotable with respect to the arm; and a controller configured to calculate an angle of the bucket with respect to the arm according to an operation command before start of excavation, and control the work implement such that the calculated angle becomes equal to a first angle.
  • a method of controlling a work vehicle is a method of controlling a work vehicle including a work implement that includes a boom pivotable with respect to a vehicular body, an arm pivotable with respect to the boom, and a bucket pivotable with respect to the arm.
  • the method includes: receiving an operation command before start of excavation; calculating an angle of the bucket with respect to the arm according to the operation command; and controlling the work implement such that the calculated angle becomes equal to a first angle.
  • the posture of the bucket is adjusted before the start of excavation, thereby eliminating the need to carry out a complicated computation during the excavation operation, so that an efficient excavation operation can be performed in a simple manner.
  • FIG. 1 is a perspective view showing an example of a work vehicle according to an embodiment.
  • FIG. 2 is a diagram schematically illustrating a work vehicle CM according to the embodiment.
  • FIG. 3 is a functional block diagram illustrating the configuration of a control system 200 configured to control work vehicle CM according to the embodiment.
  • FIG. 4 is a diagram illustrating the relation between the excavation angle of a bucket 8 and the resistance of soil according to the embodiment.
  • FIG. 5 is a diagram illustrating movement of work implement 2 in an excavation operation according to the embodiment.
  • FIG. 6 is a diagram illustrating the operation process of work vehicle CM in the excavation operation according to the embodiment.
  • FIG. 7 is a diagram illustrating the posture of bucket 8 according to the first modification of the embodiment.
  • FIG. 8 is a diagram illustrating the operation process of work vehicle CM in the excavation operation according to the first modification of the embodiment.
  • FIG. 9 is a functional block diagram illustrating the configuration of a control system 200 A according to the second modification of the embodiment.
  • FIG. 10 is a diagram illustrating the operation process of work vehicle CM in the excavation operation according to the second modification of the embodiment.
  • FIG. 11 is a functional block diagram illustrating the configuration of a control system 200 B configured to control a work vehicle according to another embodiment.
  • FIG. 12 is a diagram illustrating a concept of a work vehicle system according to another embodiment.
  • FIG. 1 is a perspective view showing an example of a work vehicle according to an embodiment.
  • a hydraulic excavator CM including a work implement 2 operated by hydraulic pressure will be hereinafter described by way of example as a work vehicle to which the concept of the present disclosure is applicable.
  • Hydraulic excavator CM includes a vehicular body 1 and a work implement 2 .
  • Vehicular body 1 includes a revolving unit 3 , an operator's cab 4 and a traveling unit 5 .
  • Revolving unit 3 is disposed on traveling unit 5 .
  • Traveling unit 5 supports revolving unit 3 .
  • Revolving unit 3 is revolvable about a revolving axis AX.
  • Operator's cab 4 is provided with an operator's seat 4 S on which an operator sits. The operator who sits in operator's cab 4 operates hydraulic excavator CM.
  • Traveling unit 5 has a pair of crawler belts 5 Cr. Rotation of crawler belts 5 Cr causes hydraulic excavator CM to travel.
  • Traveling unit 5 may be formed of wheels (tires).
  • the front-rear direction means the front-rear direction with respect to the operator who sits on operator's seat 4 S.
  • the right-left direction means the right-left direction with respect to the operator who sits on operator's seat 4 S.
  • the right-left direction corresponds to the width direction of a vehicle (the vehicle width direction).
  • the direction in which the operator sitting on operator's seat 4 S faces forward is defined as a frontward direction.
  • the direction opposite to frontward direction is defined as a rearward direction.
  • the right side and the left side of the operator sitting on the operator's seat and facing forward are defined as a rightward direction and a leftward direction, respectively.
  • the front-rear direction corresponds to an X-axis direction while the right-left direction corresponds to a Y-axis direction.
  • the direction in which the operator sitting on operator's seat faces forward corresponds to the frontward direction (a +X direction).
  • the direction opposite to the frontward direction corresponds to the rearward direction (a ⁇ X direction).
  • one direction of the vehicle width direction corresponds to the rightward direction (a +Z direction) while the other direction of the vehicle width direction corresponds to the leftward direction (a ⁇ Z direction).
  • Revolving unit 3 includes: an engine compartment 9 in which an engine is housed; and a counter weight provided in the rear portion of revolving unit 3 .
  • a handrail 19 is provided frontward of engine compartment 9 .
  • An engine, a hydraulic pump and the like are disposed in engine compartment 9 .
  • Work implement 2 is connected to revolving unit 3 .
  • Work implement 2 includes a boom 6 , an arm 7 , a bucket 8 , a boom cylinder 10 , an arm cylinder 11 , and a bucket cylinder 12 .
  • Boom 6 is connected to revolving unit 3 through a boom pin 13 .
  • Arm 7 is connected to boom 6 through an arm pin 14 .
  • Bucket 8 is connected to arm 7 through a bucket pin 15 .
  • Boom cylinder 10 drives boom 6 .
  • Arm cylinder 11 drives arm 7 .
  • Bucket cylinder 12 drives bucket 8 .
  • the base end (the boom foot) of boom 6 and revolving unit 3 are connected.
  • the leading end (the boom top) of boom 6 and the base end (the arm foot) of arm 7 are connected.
  • the leading end (the arm top) of arm 7 and the base end of bucket 8 are connected.
  • Each of boom cylinder 10 , arm cylinder 11 and bucket cylinder 12 is a hydraulic cylinder driven by hydraulic oil.
  • Boom 6 is pivotable with respect to revolving unit 3 about boom pin 13 as a pivot shaft.
  • Arm 7 is pivotable with respect to boom 6 about arm pin 14 as a pivot shaft extending in parallel to boom pin 13 .
  • Bucket 8 is pivotable with respect to arm 7 about bucket pin 15 as a pivot shaft extending in parallel to boom pin 13 and arm pin 14 .
  • Each of boom pin 13 , arm pin 14 and bucket pin 15 is in parallel to the Z-axis.
  • Each of boom 6 , arm 7 and bucket 8 is pivotable about the axis in parallel to the Z-axis.
  • FIG. 2 is a diagram schematically illustrating a work vehicle CM according to the embodiment.
  • work vehicle CM is provided with a boom cylinder stroke sensor 16 , an arm cylinder stroke sensor 17 and a bucket cylinder stroke sensor 18 .
  • Boom cylinder stroke sensor 16 is disposed at boom cylinder 10 and configured to detect the stroke length (the boom cylinder length) of boom cylinder 10 .
  • Arm cylinder stroke sensor 17 is disposed at arm cylinder 11 and configured to detect the stroke length (the arm cylinder length) of arm cylinder 11 .
  • Bucket cylinder stroke sensor 18 is disposed at bucket cylinder 12 and configured to detect the stroke length (the bucket cylinder length) of bucket cylinder 12 .
  • the stroke length of boom cylinder 10 will also be referred to as a boom cylinder length or a boom stroke.
  • the stroke length of arm cylinder 11 will also be referred to as an arm cylinder length or an arm stroke.
  • the stroke length of bucket cylinder 12 will also be referred to as a bucket cylinder length or a bucket stroke.
  • the boom cylinder length, the arm cylinder length and the bucket cylinder length will also be collectively referred to as cylinder length data.
  • Boom 6 has a length L 1 corresponding to the distance between boom pin 13 and arm pin 14 .
  • Arm 7 has a length L 2 corresponding to the distance between arm pin 14 and bucket pin 15 .
  • Bucket 8 has a length L 3 corresponding to the distance between bucket pin 15 and a cutting edge 8 a of bucket 8 .
  • Bucket 8 has a plurality of blades. The leading end of bucket 8 will be referred to as cutting edge 8 a. Bucket 8 may not have a blade.
  • the leading end of bucket 8 may be formed of a steel plate having a straight shape.
  • FIG. 2 shows vehicular body coordinate systems of an X-axis and a Y-axis with respect to boom pin 13 as a reference point (reference position).
  • an inclination angle ⁇ 1 of boom 6 with respect to the horizontal direction in the vehicular body coordinate systems is calculated.
  • Inclination angle ⁇ 1 represents an angle formed between the horizontal line (X-axis) and the line segment that connects boom pin 13 and arm pin 14 .
  • Inclination angle ⁇ 2 represents an angle formed between: the line segment that connects boom pin 13 and arm pin 14 ; and the line segment that connects arm pin 14 and bucket pin 15 .
  • an inclination angle ⁇ 3 of cutting edge 8 a provided in bucket 8 with respect to arm 7 is calculated.
  • Inclination angle ⁇ 3 represents an angle formed between: the line segment that connects arm pin 14 and bucket pin 15 ; and the line segment that connects bucket pin 15 and cutting edge 8 a of bucket 8 .
  • Inclination angle ⁇ 3 will also be referred to as a bucket angle that represents an angle of bucket 8 with respect to arm 7 .
  • the inclination angle may be calculated by using an angle detector such as a rotary encoder.
  • the horizontal line is detected by an inertial measurement unit (not shown), but may be detected by an inclination sensor, an acceleration sensor and the like.
  • FIG. 3 is a functional block diagram illustrating the configuration of a control system 200 configured to control work vehicle CM according to the embodiment.
  • control system 200 is configured to control the operation of excavation performed using work implement 2 .
  • Control system 200 includes a boom cylinder stroke sensor 16 , an arm cylinder stroke sensor 17 , a bucket cylinder stroke sensor 18 , an operation device 25 , a work implement controller 26 , a hydraulic cylinder 60 , a direction control valve 64 , and a pressure sensor 66 .
  • Operation device 25 is disposed in operator's cab 4 . Operation device 25 is operated by an operator. Operation device 25 receives an operation command from the operator for driving work implement 2 . Operation device 25 is an operation device of a pilot hydraulic type.
  • Directional control valve 64 adjusts the amount of hydraulic oil supplied to hydraulic cylinder 60 .
  • Direction control valve 64 is operated by the supplied oil.
  • the oil supplied to the hydraulic cylinder for actuating the hydraulic cylinder (boom cylinder 10 , arm cylinder 11 and bucket cylinder 12 ) is also referred to as hydraulic oil.
  • the oil supplied to direction control valve 64 for actuating direction control valve 64 is also referred to as pilot oil.
  • the pressure of the pilot oil is also referred to as a pilot oil pressure.
  • the hydraulic oil and the pilot oil may be discharged from the same hydraulic pump.
  • a part of the hydraulic oil discharged from the hydraulic pump may be decompressed by a pressure reducing valve, and the decompressed hydraulic oil may be used as pilot oil.
  • the hydraulic pump (a main hydraulic pump) for pumping out hydraulic oil is different from the hydraulic pump for pumping out pilot oil (a pilot hydraulic pump).
  • the pilot oil that is discharged from the main hydraulic pump and decompressed by the pressure reducing valve is supplied to operation device 25 .
  • the pilot oil pressure is adjusted based on the amount of operation of operation device 25 .
  • Pressure sensor 66 is connected to operation device 25 .
  • Pressure sensor 66 detects the pilot oil pressure that is generated according to the lever operation of operation device 25 , and outputs the detected pilot oil pressure to work implement controller 26 .
  • work implement controller 26 drives direction control valve 64 through which the hydraulic oil to be supplied to hydraulic cylinder 60 (boom cylinder 10 , arm cylinder 11 and bucket cylinder 12 ) flows.
  • Operation device 25 includes a first operation lever 25 R, a second operation lever 25 L, and an excavation button 25 P.
  • First operation lever 25 R is disposed on the right side of operator's seat 4 S.
  • Second operation lever 25 L is disposed on the left side of operator's seat 4 S.
  • first operation lever 25 R and second operation lever 25 L the forward-backward and the rightward-leftward operations correspond to operations along two axes.
  • Excavation button 25 P is used by an operator for instructing start of the excavation operation. According to the instruction given from the operator by pressing excavation button 25 P, work implement controller 26 controls the posture of work implement 2 for the excavation operation. Specifically, the bucket angle is adjusted to a prescribed angle (the first angle), which will be described later.
  • Boom 6 and bucket 8 are operated by first operation lever 25 R.
  • first operation lever 25 R in the front-rear direction corresponds to the operation of boom 6 .
  • Boom 6 is raised and lowered according to the operation in the front-rear direction.
  • the lever operation is performed for operating boom 6 .
  • first operation lever 25 R in the right-left direction corresponds to the operation of bucket 8 .
  • the excavation motion and the opening motion of bucket 8 are performed according to the operation in the right-left direction.
  • the lever operation is performed for operating bucket 8 .
  • Arm 7 and revolving unit 3 are operated by second operation lever 25 L.
  • second operation lever 25 L in the front-rear direction corresponds to the operation of arm 7 .
  • Arm 7 is raised and lowered according to the operation in the front-rear direction.
  • the lever operation is performed for operating arm 7 .
  • second operation lever 25 L in the right-left direction corresponds to revolution of revolving unit 3 .
  • Revolving unit 3 is revolved in the rightward direction and the leftward direction according to the operation in the right-left direction.
  • work implement controller 26 drives direction control valve 64 through which the hydraulic oil to be supplied to boom cylinder 10 for driving boom 6 flows.
  • work implement controller 26 drives direction control valve 64 through which the hydraulic oil to be supplied to bucket cylinder 12 for driving bucket 8 flows.
  • work implement controller 26 drives direction control valve 64 through which the hydraulic oil to be supplied to arm cylinder 11 for driving arm 7 flows.
  • work implement controller 26 drives direction control valve 64 through which the hydraulic oil to be supplied to the hydraulic actuator for driving revolving unit 3 flows.
  • first operation lever 25 R in the right-left direction may correspond to the operation of boom 6 while the operation of first operation lever 25 R in the front-rear direction may correspond to the operation of bucket 8 .
  • second operation lever 25 L in the right-left direction may correspond to the operation of arm 7 while the operation of second operation lever 25 L in the front-rear direction may correspond to the operation of revolving unit 3 .
  • FIG. 4 is a diagram illustrating the relation between the excavation angle of bucket 8 and the resistance of soil according to the embodiment.
  • the excavation angle of bucket 8 close to 0° is shown as a limit angle.
  • the excavation angle represents an angle between the direction of cutting edge 8 a of bucket 8 and the excavation direction (traveling direction) of cutting edge 8 a when bucket 8 is moved.
  • the excavation angle shows a positive value when the excavation direction of cutting edge 8 a is toward the opening of bucket 8 during movement of bucket 8 with respect to the direction of cutting edge 8 a of bucket 8 .
  • the excavation angle also shows a negative value when the excavation direction of cutting edge 8 a is opposite to the opening of bucket 8 .
  • the resistance of soil against bucket 8 shows a minimum value.
  • the limit angle and prescribed angle Q are merely by way of examples and can be set at different values depending on the configuration of bucket 8 .
  • Work vehicle CM performs an efficient excavation operation in a simple manner by performing the excavation operation at an excavation angle at which the value of the resistance of soil is relatively small. Specifically, work vehicle CM performs the excavation operation in such a manner that the excavation angle becomes equal to prescribed angle Q.
  • the manner that the excavation angle becomes equal to prescribed angle Q does not mean that the excavation angle becomes completely equal to prescribed angle Q, but may also include the case where the excavation angle becomes equal to the approximate value of prescribed angle Q.
  • FIG. 5 is a diagram illustrating the movement of work implement 2 in the excavation operation according to the embodiment.
  • FIG. 5 shows the case where arm 7 is operated.
  • arm 7 is operated to cause bucket 8 to dig into soil.
  • the excavation angle in the excavation operation performed by operating arm 7 is fixed.
  • the excavation operation can be performed at an excavation angle Q by operating arm 7 .
  • the angle of bucket 8 with respect to arm 7 is adjusted to bucket angle P before the start of excavation such that the excavation angle in the excavation operation performed by operating arm 7 becomes equal to an optimum excavation angle (angle Q).
  • angle Q an optimum excavation angle
  • work implement controller 26 calculates the angle of bucket 8 with respect to arm 7 according to the operation command before the start of excavation, and controls the work implement such that the calculated angle becomes equal to a prescribed angle (angle P).
  • FIG. 6 is a diagram illustrating the operation process of work vehicle CM in the excavation operation according to the embodiment.
  • work implement controller 26 determines whether an input by excavation button 25 P has been received or not (step S 2 ). Specifically, work implement controller 26 determines whether an instruction given by the operation of an operator pressing excavation button 25 P has been received or not.
  • step S 2 when work implement controller 26 determines that an input by excavation button 25 P has been received (YES in step S 2 ), it calculates a bucket angle (step S 4 ).
  • work implement controller 26 calculates an angle (bucket angle) ⁇ 3 of bucket 8 with respect to arm 7 .
  • step S 2 when work implement controller 26 determines that no input by excavation button 25 P has been received (NO in step S 2 ), it maintains the state in step S 2 .
  • work implement controller 26 adjusts bucket angle ⁇ 3 to bucket angle P (step S 6 ).
  • Work implement controller 26 drives direction control valve 64 such that bucket angle ⁇ 3 is set at bucket angle P, and adjusts the hydraulic oil that is to be supplied to bucket cylinder 12 .
  • work implement controller 26 adjusts bucket angle ⁇ 3 to bucket angle P such that the excavation angle formed between the excavation direction of cutting edge 8 a of bucket 8 and the direction of cutting edge 8 a of bucket 8 becomes equal to prescribed angle Q.
  • the posture of bucket 8 is adjusted before the start of excavation, that is, before the start of the excavation operation. Automatic control is performed such that the excavation angle achieved by operating arm 7 for the posture of bucket 8 becomes an optimum angle. Thereby, the resistance (load) of soil against bucket 8 at the start of excavation is reduced.
  • a complicated computation does not have to be done during the excavation operation, so that an efficient excavation operation can be performed in a simple manner.
  • a work vehicle controls bucket 8 according to another operation command, not according to the instruction given by the operation of the operator pressing excavation button 25 P.
  • the work vehicle according to the first modification of the embodiment determines whether the posture of bucket 8 is in the soil ejecting state or not. Then, when the posture of bucket 8 is in the soil ejecting state, the work vehicle autonomously adjusts the angle of bucket 8 .
  • the work vehicle determines whether the soil ejecting state occurs or not.
  • FIG. 7 is a diagram illustrating the posture of bucket 8 according to the first modification of the embodiment.
  • FIG. 7 shows the case where angle ⁇ 3 of bucket 8 with respect to arm 7 is 0.
  • the figure shows a bucket-horizontal line angle ⁇ b formed between the horizontal line and the line segment that connects bucket pin 15 as the center of rotation of bucket 8 and cutting edge 8 a of bucket 8 , in the case where angle ⁇ 3 of bucket 8 with respect to arm 7 is ⁇ .
  • This bucket-horizontal line angle ⁇ b represents an angle of bucket 8 with respect to the horizontal line.
  • Bucket-horizontal line angle ⁇ b is calculated by the following equation based on inclination angles ⁇ 1 to ⁇ 3 .
  • ⁇ b 180°+ ⁇ 1 ⁇ 2′′ ⁇ 3
  • bucket-horizontal line angle ⁇ b When bucket-horizontal line angle ⁇ b is less than 90°, soil is more likely to be accumulated in bucket 8 . When bucket-horizontal line angle ⁇ b is equal to or greater than 90°, soil is more likely to be ejected from bucket 8 . When bucket-horizontal line angle ⁇ b is 180°, soil is completely ejected from bucket 8 .
  • bucket-horizontal line angle ⁇ b is equal to or greater than a prescribed angle, it is determined that the soil ejecting state occurs.
  • FIG. 8 is a diagram illustrating the operation process of work vehicle CM in the excavation operation according to the first modification of the embodiment.
  • work implement controller 26 determines whether bucket 8 is operated or not (step S 10 ). Specifically, work implement controller 26 determines whether or not first operation lever 25 R is operated in the right-left direction.
  • step S 10 When work implement controller 26 determines in step S 10 that bucket 8 is operated (YES in step S 10 ), it calculates the bucket angle (step S 11 ).
  • work implement controller 26 calculates angle (bucket angle) ⁇ 3 of bucket 8 with respect to arm 7 .
  • step S 10 When work implement controller 26 determines in step S 10 that bucket 8 is not operated (NO in step S 10 ), the state in step S 10 is maintained.
  • work implement controller 26 calculates bucket-horizontal line angle ⁇ b (step S 12 ).
  • bucket-horizontal line angle ⁇ b formed between the horizontal line and the line segment that connects bucket pin 15 and cutting edge 8 a of bucket 8 is calculated.
  • Inclination angles ⁇ 1 and ⁇ 2 are calculated based on the detection results from boom cylinder stroke sensor 16 and arm cylinder stroke sensor 17 , respectively. When inclination angles ⁇ 1 and ⁇ 2 are calculated before the operation of bucket 8 , these values can also be utilized.
  • work implement controller 26 determines whether or not the calculated bucket-horizontal line angle ⁇ b is equal to or greater than a prescribed angle R (step S 14 ).
  • Prescribed angle R is equal to or greater than 90°.
  • step S 14 When work implement controller 26 determines in step S 14 that the calculated bucket-horizontal line angle ⁇ b is equal to or greater than prescribed angle R (YES in step S 14 ), work implement controller 26 determines whether the operation of the bucket ends or not (step S 16 ).
  • step S 14 When work implement controller 26 determines in step S 14 that the calculated bucket-horizontal line angle ⁇ b is less than prescribed angle R (NO in step S 14 ), the process is returned to step S 10 .
  • work implement controller 26 determines in step S 16 that the operation of the bucket ends (YES in step S 16 ), it adjusts bucket angle ⁇ 3 to bucket angle P (step S 18 ).
  • Work implement controller 26 drives direction control valve 64 , through which the hydraulic oil to be supplied to bucket cylinder 12 flows, so as to set bucket angle ⁇ 3 to be bucket angle P.
  • work implement controller 26 adjusts bucket angle ⁇ 3 to bucket angle P such that the excavation angle formed between the excavation direction of cutting edge 8 a of bucket 8 and the direction of cutting edge 8 a of bucket 8 becomes equal to prescribed angle Q.
  • the posture of bucket 8 is adjusted before the start of excavation, that is, before the excavation operation is started. Automatic control is performed such that the excavation angle achieved by operating arm 7 for the posture of bucket 8 becomes an optimum angle. Thereby, the resistance (load) of soil against bucket 8 at the start of excavation is reduced.
  • a complicated computation does not have to be done during the excavation operation, so that an efficient excavation operation can be performed in a simple manner.
  • work implement controller 26 calculates bucket-horizontal line angle ⁇ b as the angle of bucket 8 with respect to the horizontal line, and determines whether or not bucket-horizontal line angle ⁇ b is equal to or greater than prescribed angle R. When it is determined that bucket-horizontal line angle ⁇ b is equal to or greater than prescribed angle R, it is determined that the posture of bucket 8 is in the soil ejecting state. When work implement controller 26 determines that the soil ejecting state occurs, it adjusts the angle of bucket 8 to bucket angle P.
  • bucket 8 can be autonomously controlled to be set at a prescribed bucket angle before the start of excavation according to the command to operate bucket 8 . Accordingly, the operation load onto the operator can be reduced, and also, an efficient excavation operation can be simply performed.
  • the work vehicle according to the second modification of the embodiment further determines the load onto work implement 2 , and, when it determines that the soil ejecting state occurs, it autonomously adjusts the angle of bucket 8 .
  • FIG. 9 is a functional block diagram illustrating the configuration of a control system 200 A according to the second modification of the embodiment.
  • control system 200 A is different from control system 200 in that it further includes a load sensor 28 , and that operation device 25 is replaced with an operation device 25 #.
  • operation device 25 # has a configuration from which excavation button 25 P is removed, as compared with operation device 25 . Since other configurations are the same as those described with reference to FIG. 3 , the detailed description thereof will not be repeated.
  • Load sensor 28 is attached to bucket 8 .
  • work implement controller 26 determines whether work implement 2 has performed the soil ejecting operation or not.
  • load sensor 28 is increased in accordance with the excavation operation in which bucket 8 excavates soil.
  • the value of load sensor 28 is decreased in accordance with the soil ejecting operation in which bucket 8 ejects soil.
  • Work implement controller 26 determines whether or not the value of the load is equal to or greater than the first value in accordance with the detection result from load sensor 28 . When the value of the load is equal to or greater than the first value, work implement controller 26 determines that the excavation operation has been performed.
  • work implement controller 26 determines whether or not the value of the load is less than the second value smaller than the first value in accordance with the detection result from load sensor 28 .
  • work implement controller 26 determines that the soil ejecting operation has been performed.
  • the first value and the second value may also be the same value.
  • FIG. 10 is a diagram illustrating the operation process of work vehicle CM in the excavation operation according to the second modification of the embodiment.
  • work implement controller 26 determines whether or not the load is relatively large according to the detection result from load sensor 28 (step S 20 ). Specifically, work implement controller 26 determines whether or not the value is equal to or greater than the first value in accordance with the detection result from load sensor 28 . Work implement controller 26 determines whether the excavation operation has been performed or not.
  • step S 20 When work implement controller 26 determines in step S 20 that the load is relatively large according to the detection result from load sensor 28 (YES in step S 20 ), the process proceeds to step S 22 .
  • step S 20 When work implement controller 26 determines in step S 20 that the load is not relatively large according to the detection result from load sensor 28 (NO in step S 20 ), the state in step S 20 is maintained.
  • step S 22 work implement controller 26 determines whether bucket 8 is operated or not. Specifically, work implement controller 26 determines whether first operation lever 25 R is operated in the right-left direction.
  • step S 22 determines whether or not the load of the bucket is relatively small (step S 24 ). Specifically, work implement controller 26 determines whether or not the value is less than the second value in accordance with the detection result from load sensor 28 . Work implement controller 26 determines whether the soil ejecting operation has been performed or not.
  • step S 22 When work implement controller 26 determines in step S 22 that bucket 8 is not operated (NO in step S 22 ), the state in step S 22 is maintained.
  • step S 24 When work implement controller 26 determines in step S 24 that the load of bucket 8 is relatively small (YES in step S 24 ), the bucket angle is calculated (step S 11 ). Specifically, based on the detection result from bucket cylinder stroke sensor 18 , work implement controller 26 calculates angle (bucket angle) ⁇ 3 of bucket 8 with respect to arm 7 .
  • step S 24 When work implement controller 26 determines in step S 24 that the load is not relatively small according to the detection result from load sensor 28 (NO in step S 24 ), the process is returned to step S 22 .
  • work implement controller 26 calculates bucket-horizontal line angle ⁇ b (step S 12 ). Since a series of processes in steps S 11 to S 18 is the same as those described with reference to FIG. 8 , the detailed description thereof will not be repeated.
  • work implement controller 26 determines whether the soil ejecting operation has been performed or not. When work implement controller 26 determines that the soil ejecting operation has been performed, then, according to the command to operate bucket 8 , it calculates bucket-horizontal line angle ⁇ b and determines whether or not bucket-horizontal line angle ⁇ b is equal to or greater than prescribed angle R. Thereby, it is determined whether the posture of bucket 8 is in the soil ejecting state or not. When the posture of bucket 8 is in the soil ejecting state, bucket angle ⁇ 3 is adjusted to bucket angle P.
  • work implement controller 26 determines whether the soil ejecting operation has been performed or not.
  • work implement controller 26 determines whether the soil ejecting operation has been performed or not. Accordingly, work implement controller 26 can reliably determine whether the soil ejecting operation has been performed or not. Then, before the start of excavation at which it was reliably determined that the soil ejecting operation has been performed, bucket angle ⁇ 3 is adjusted to bucket angle P.
  • work implement controller 26 determines with sufficient accuracy that the soil ejecting operation has already been performed and excavation is not yet started (before start of excavation).
  • an efficient excavation operation can be performed in a simple manner.
  • load sensor 28 is attached to bucket 8
  • the configuration of detecting a load by a sensor for measuring the hydraulic pressure inside the hydraulic cylinder may be employed.
  • the hydraulic pressure of the hydraulic oil supplied to bucket cylinder 12 is measured by a sensor, so that it can be determined whether the load applied onto bucket 8 is relatively large or small.
  • FIG. 11 is a functional block diagram illustrating the configuration of a control system 200 B configured to control a work vehicle according to another embodiment.
  • control system 200 B is different from control system 200 A in that a receiver 29 is provided in place of load sensor 28 . Since other configurations are the same as those described with reference to FIG. 9 , the detailed description thereof will not be repeated.
  • Receiver 29 outputs the received command to work implement controller 26 .
  • Receiver 29 receives an excavation start command transmitted from outside, and outputs the received command to work implement controller 26 .
  • work implement controller 26 calculates the angle of bucket 8 with respect to arm 7 , and controls the work implement such that the calculated angle becomes equal to a prescribed angle.
  • the above-described operation process is performed upon reception of the excavation start command in place of reception of the input by excavation button 25 P that has been described with reference to FIG. 6 .
  • the posture of bucket 8 is adjusted before the start of excavation, that is, before the excavation operation is started.
  • Automatic control is performed such that the excavation angle achieved by operating arm 7 for the posture of bucket 8 becomes an optimum angle. Thereby, the resistance (load) of soil against bucket 8 at the start of excavation is reduced.
  • An efficient excavation operation can be performed according to the operation start command from outside.
  • FIG. 12 is a diagram illustrating a concept of a work vehicle system according to another embodiment.
  • the work vehicle system configures a control system for controlling work vehicle CM from an external base station 300 .
  • the functions of work implement controller 26 and operation device 25 that have been described with reference to FIG. 3 are provided in external base station 300 and the like.
  • Base station 300 includes: a work implement controller 26 # having the same function as that of work implement controller 26 , and an operation device 25 # having the same function as that of operation device 25 .
  • Work implement controller 26 # receives the operation command of operation device 25 #, and outputs a motion command for controlling work vehicle CM.
  • Work vehicle CM operates according to the motion command from work implement controller 26 #.
  • work implement controller 26 # outputs the motion command for driving direction control valve 64 that has been described with reference to FIG. 3 .
  • Work implement controller 26 # receives the input of the sensor information from each of boom cylinder stroke sensor 16 , arm cylinder stroke sensor 17 , and bucket cylinder stroke sensor 18 .
  • the operation process of the excavation operation according to the embodiment that has been described with reference to FIG. 6 can be performed by work implement controller 26 #.
  • the present invention is also applicable to the configuration in which work vehicle CM is autonomously controlled without providing an operation device.
  • the present invention is also applicable to the case where an operation command for the excavation operation is programmed in advance, and the work implement controller is operated according to the programmed operation command.
  • an autonomous control program for autonomously controlling work vehicle CM is started according to the instruction from the user, and the work implement controller starts the excavation operation according to the programmed operation command, the following process may be included, in which the angle of bucket 8 with respect to arm 7 is calculated, and the work implement is operated such that the calculated angle becomes equal to a prescribed angle.
  • Work vehicle CM in the embodiment includes vehicular body 1 and work implement 2 as shown in FIG. 1 .
  • Work implement 2 includes boom 6 pivotable with respect to vehicular body 1 , arm 7 pivotable with respect to boom 6 , and bucket 8 pivotable with respect to arm 7 .
  • Work vehicle CM is provided with work implement controller 26 as shown in FIG. 3 .
  • Work implement controller 26 calculates the angle of bucket 8 with respect to arm 7 according to the input (excavation command) by excavation button 25 P before the start of excavation, and controls bucket 8 such that the calculated angle becomes equal to bucket angle P.
  • Work vehicle CM in the embodiment controls bucket 8 to be set at bucket angle P before the start of excavation. Accordingly, the excavation operation of work implement 2 is performed at the excavation angle of prescribed angle Q at which the resistance of soil shows a minimum value, as shown in FIG. 4 .
  • a complicated computation does not have to be done during the excavation operation, so that an efficient excavation operation can be performed in a simple manner.
  • Work vehicle CM in the embodiment is provided with work implement controller 26 configured to determine whether the soil ejecting operation as shown in FIG. 7 has been performed or not according to the operation command.
  • work implement controller 26 determines that the soil ejecting operation has been performed, it calculates the angle of bucket 8 with respect to arm 7 , and controls bucket 8 such that the calculated angle becomes equal to bucket angle P.
  • Work vehicle CM in the embodiment determines whether the soil ejecting operation of bucket 8 has been performed or not, and controls bucket 8 to be set at bucket angle P before the start of excavation. Accordingly, when the soil ejecting operation of bucket 8 has been performed, the preparations before the start of excavation are made. Thus, an efficient excavation operation can be performed in a simple manner.
  • Bucket-horizontal line angle ⁇ b represents an angle formed between the horizontal line and the line segment that connects bucket pin 15 and cutting edge 8 a of bucket 8 .
  • bucket 8 is controlled such that the calculated angle becomes equal to bucket angle P.
  • work vehicle CM in the embodiment determines that the posture of bucket 8 is in the soil ejecting state, and controls bucket 8 to be set at bucket angle P before the start of excavation. Accordingly, after it is determined based on the posture of bucket 8 whether the soil ejecting state occurs or not, the preparations before the start of excavation are made. Thus, it becomes possible to readily recognize that the soil ejecting state occurs. Also, an efficient excavation operation can be performed in a simple manner.
  • Work vehicle CM in the embodiment is provided with load sensor 28 for detecting the load applied to bucket 8 .
  • Work implement controller 26 calculates the angle of bucket 8 with respect to arm 7 based on the operation command of first operation lever 25 R before the start of excavation and the detection result from load sensor 28 during excavation. Then, work implement controller 26 controls bucket 8 such that the calculated angle becomes equal to bucket angle P.
  • work vehicle CM in the embodiment determines whether the soil ejecting operation has been performed or not. Then, when work vehicle CM in the embodiment determines that soil ejecting operation has been performed, it controls bucket 8 to be set at bucket angle P before the start of excavation. Thus, after it is determined based on the detection result from the load sensor whether the soil ejecting state occurs or not, the preparations before the start of excavation are made. Accordingly, it becomes possible to accurately recognize that the soil ejecting state occurs. Also, an efficient excavation operation can be performed in a simple manner.
  • Work vehicle CM in the embodiment is provided with receiver 29 configured to receive an operation start command as shown in FIG. 11 .
  • work implement controller 26 calculates the angle of bucket 8 with respect to arm 7 , and controls bucket 8 such that the calculated angle becomes equal to bucket angle P.
  • work vehicle CM in the embodiment controls bucket 8 to be set at bucket angle P before the start of excavation.
  • work vehicle CM in the embodiment is provided with bucket cylinder 12 configured to drive bucket 8 according to the operation command before the start of excavation.
  • Work implement controller 26 calculates the angle of bucket 8 with respect to arm 7 based on the stroke length of bucket cylinder 12 , and controls bucket 8 such that the calculated angle becomes equal to bucket angle P.
  • Work vehicle CM in the embodiment can calculate the angle of bucket 8 with respect to arm 7 based on the stroke length of bucket cylinder 12 . This eliminates the need to provide a detector for detecting the angle of bucket 8 , so that an efficient excavation operation can be performed in a simple manner.
  • Work vehicle CM in the embodiment is provided with vehicular body 1 and work implement 2 as shown in FIG. 1 .
  • Work implement 2 includes boom 6 pivotable with respect to vehicular body 1 , arm 7 pivotable with respect to boom 6 , and bucket 8 pivotable with respect to arm 7 .
  • the following steps are performed, which include: receiving an operation command before start of excavation; calculating an angle of bucket 8 with respect to arm 7 according to the operation command; and controlling bucket 8 such that the calculated angle becomes equal to bucket angle P.
  • bucket 8 is controlled to be set at bucket angle P before the start of excavation.
  • the excavation operation of work implement 2 is performed at the excavation angle of prescribed angle Q at which the resistance of soil shows a minimum value, as shown in
  • FIG. 4 As a result, by adjusting the posture of bucket 8 before the start of excavation, a complicated computation does not have to be done during the excavation operation, so that an efficient excavation operation can be performed in a simple manner.
  • a hydraulic excavator has been described above as an example of a work vehicle, but the present invention is applicable also to a work vehicle such as a bulldozer and a wheel loader.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Operation Control Of Excavators (AREA)
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JP2017-030421 2017-02-21
PCT/JP2018/005885 WO2018155407A1 (ja) 2017-02-21 2018-02-20 作業車両および作業車両の制御方法

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WO2018155407A1 (ja) 2018-08-30

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