WO2024111321A1

WO2024111321A1 - Work state determining device, work state determining method, and work vehicle

Info

Publication number: WO2024111321A1
Application number: PCT/JP2023/038332
Authority: WO
Inventors: 亨志馬込; 康太山口; 謙太郎田島
Original assignee: 株式会社小松製作所
Priority date: 2022-11-24
Filing date: 2023-10-24
Publication date: 2024-05-30
Also published as: JP2024076095A

Abstract

This work state determining device comprises: an acquiring unit for acquiring a detection result of a hydraulic pressure detecting unit for detecting hydraulic pressures of a plurality of hydraulic cylinders that use hydraulic pressure to drive a blade mounted on a work vehicle; and a work state determining unit which determines that the blade is in a working work state if the blade is determined to be in a state of being grounded by any of the plurality of hydraulic cylinders, on the basis of the hydraulic pressures detected by the hydraulic pressure detecting unit and a first reference pressure, or if the blade is determined to be in a state of being grounded by any of the hydraulic cylinders, on the basis of a calculated value based on the plurality of hydraulic pressures detected in the plurality of hydraulic cylinders by the hydraulic pressure detecting unit and a second reference pressure different from the first reference pressure.

Description

Work condition determination device, work condition determination method, and work vehicle

The present disclosure relates to a work condition determination device, a work condition determination method, and a work vehicle.
This application claims priority based on Japanese Patent Application No. 2022-187482, filed on November 24, 2022, the contents of which are incorporated herein by reference.

Patent Document 1 describes a motor grader equipped with a control unit that determines that the vehicle is in a traveling state when the hydraulic pressure supplied to the hydraulic cylinder that drives the blade is below a predetermined threshold, and determines that the vehicle is in a working state when the hydraulic pressure is equal to or greater than the predetermined threshold. In the motor grader described in Patent Document 1, when it is determined that the vehicle is in a traveling state, the hydraulic pressure supplied to the clutch is controlled with a hydraulic waveform corresponding to the traveling state, and when it is determined that the vehicle is in a working state, the hydraulic pressure supplied to the clutch is controlled with a hydraulic waveform corresponding to the working state.

Japanese Patent Publication No. 2008-248918

When determining whether the vehicle is in a traveling state or a working state based only on the magnitude relationship with respect to a threshold value, as described in paragraph 0008 of Patent Document 1, depending on the size of the threshold value, even when the vehicle is determined to be in a traveling state, the blade may be in contact with the ground and traveling while receiving a relatively light load. In other words, when it should be determined that the vehicle is working, it may be determined that the vehicle is traveling rather than working. This is not a problem for the purpose of selecting a hydraulic waveform, but if it is desired to accurately determine whether or not the vehicle is working, improving the accuracy of the determination becomes an issue.

This disclosure has been made in consideration of the above circumstances, and aims to provide a work state determination device, a work state determination method, and a work vehicle that can appropriately determine whether or not work is in progress.

One aspect of the present disclosure is a work state determination device that includes an acquisition unit that acquires the detection results of a hydraulic detection unit that detects hydraulic pressures of multiple hydraulic cylinders that hydraulically drive a blade mounted on a work vehicle, and a work state determination unit that determines that the work state of the blade is in operation when it is determined that any of the multiple hydraulic cylinders is in a state where the blade is grounded based on the hydraulic pressure detected by the hydraulic detection unit and a first reference pressure, or when it is determined that any of the multiple hydraulic cylinders is in a state where the blade is grounded based on a calculated value based on the multiple hydraulic pressures detected by the hydraulic detection unit at the multiple hydraulic cylinders and a second reference pressure different from the first reference pressure.

Another aspect of the present disclosure is a method for determining a working state, including the steps of: acquiring a detection result from a hydraulic detection unit that detects hydraulic pressures of multiple hydraulic cylinders that hydraulically drive a blade mounted on a work vehicle; and determining that the working state of the blade is in operation if it is determined that any of the multiple hydraulic cylinders is in a state where the blade is in contact with the ground based on the hydraulic pressures detected by the hydraulic detection unit and a first reference pressure, or if it is determined that any of the multiple hydraulic cylinders is in a state where the blade is in contact with the ground based on a calculated value based on the multiple hydraulic pressures detected by the hydraulic detection unit at the multiple hydraulic cylinders and a second reference pressure different from the first reference pressure.

Another aspect of the present disclosure is a work vehicle that includes a blade, a plurality of hydraulic cylinders that hydraulically drive the blade, a hydraulic pressure detection unit that detects the hydraulic pressure of the plurality of hydraulic cylinders, an acquisition unit that acquires the detection result of the hydraulic pressure detection unit, and a work state determination unit that determines that the work state of the blade is in operation when it is determined that any of the plurality of hydraulic cylinders is in a state where the blade is in contact with the ground based on the hydraulic pressure detected by the hydraulic pressure detection unit and a first reference pressure, or when it is determined that any of the plurality of hydraulic cylinders is in a state where the blade is in contact with the ground based on a calculated value based on the plurality of hydraulic pressures detected by the hydraulic pressure detection unit and a second reference pressure different from the first reference pressure.

The work state determination device, work state determination method, and work vehicle disclosed herein can appropriately determine whether or not work is in progress.

1 is a perspective view showing a basic configuration example of a motor grader according to an embodiment of the present disclosure. FIG. FIG. 1 is a perspective view showing an example of a basic configuration of a work machine of a motor grader according to an embodiment of the present disclosure. FIG. 1 is a block diagram showing a configuration example of a control system according to an embodiment of the present disclosure. 1 is a block diagram showing an example configuration of a hydraulic control valve unit according to an embodiment of the present disclosure. FIG. 5A to 5C are schematic diagrams illustrating an example of the operation of a blade lift cylinder according to an embodiment of the present disclosure. 1 is a block diagram showing an example of a configuration of a work state determination device according to an embodiment of the present disclosure. 4 is a state transition diagram illustrating an example of operation of the work state determination device according to an embodiment of the present disclosure. FIG. 5A to 5C are schematic diagrams illustrating an example of operation of a work machine according to an embodiment of the present disclosure. 5A to 5C are schematic diagrams illustrating an example of operation of a work machine according to an embodiment of the present disclosure. 5A to 5C are schematic diagrams illustrating an example of operation of a work machine according to an embodiment of the present disclosure. 5A to 5C are schematic diagrams illustrating an example of operation of a work machine according to an embodiment of the present disclosure. 5A to 5C are schematic diagrams illustrating an example of operation of a work machine according to an embodiment of the present disclosure. 5A to 5C are schematic diagrams for explaining an example of the operation of the working state determination device according to an embodiment of the present disclosure. 5A to 5C are schematic diagrams for explaining an example of the operation of the working state determination device according to an embodiment of the present disclosure. 5 is a flowchart illustrating an example of an operation of the working state determination device according to an embodiment of the present disclosure. 5 is a flowchart illustrating an example of an operation of the working state determination device according to an embodiment of the present disclosure.

Below, an embodiment of the present disclosure will be described with reference to Figures 1 to 16. Figure 1 is a perspective view showing a basic configuration example of a motor grader according to an embodiment of the present disclosure. Figure 2 is a perspective view showing a basic configuration example of a working machine of a motor grader according to an embodiment of the present disclosure. Figure 3 is a block diagram showing a configuration example of a control system according to an embodiment of the present disclosure. Figure 4 is a block diagram showing a configuration example of a hydraulic control valve unit according to an embodiment of the present disclosure. Figure 5 is a schematic diagram showing an operation example of a blade lift cylinder according to an embodiment of the present disclosure. Figure 6 is a block diagram showing a configuration example of a working state determination device according to an embodiment of the present disclosure. Figure 7 is a state transition diagram showing an operation example of a working state determination device according to an embodiment of the present disclosure. Figures 8 to 12 are schematic diagrams showing an operation example of a working machine according to an embodiment of the present disclosure. Figures 13 and 14 are schematic diagrams for explaining an operation example of a working state determination device according to an embodiment of the present disclosure. Figures 15 and 16 are flowcharts showing an operation example of a working state determination device according to an embodiment of the present disclosure. Note that the same or corresponding configurations in each figure are designated by the same reference numerals and the description will be omitted as appropriate.

[Overview of the work machine]
Fig. 1 shows a work machine 1 according to an embodiment. Fig. 2 shows an example of a basic configuration of a work implement 10 of the work machine 1 according to the embodiment. The work machine 1 according to the embodiment is a motor grader (also simply referred to as a grader). In the following description, the work machine 1 will be referred to as the motor grader 1 as appropriate. The motor grader 1 is also an example of a work vehicle.

In this embodiment, as shown in FIG. 1, the vehicle width direction based on the vehicle body 2 of the motor grader 1 is defined as the left-right direction, the vertical direction perpendicular to the left-right direction is defined as the up-down direction, and the vehicle length direction perpendicular to the left-right direction and the up-down direction is defined as the front-rear direction.

As shown in FIG. 1, the motor grader 1 has a vehicle body 2, a cab 3, a traveling device 4, and a working machine 10. The motor grader 1 travels on the traveling device 4 at the work site. The motor grader 1 performs work at the work site using the working machine 10. Using the working machine 10, the motor grader 1 can perform work such as road construction (cutting and shaping roadbeds, road bases, and slopes), road maintenance and repair (cutting gravel roads and leveling gravel), snow removal (removal of accumulated snow and compacted snow), and other work (leveling open spaces, digging trenches, weeding, etc.). Note that the working machine 1 is not limited to the motor grader 1, and may be any machine equipped with a working machine 10 having a blade (also called a blade or blade) driven by multiple hydraulic cylinders.

The cab 3 is supported by the vehicle body 2. Inside the cab 3, there is a driver's seat 31 where the operator sits, and an operator operation device 30 (Figure 3) that is operated by the operator to operate the motor grader 1.

The traveling gear 4 supports the vehicle body 2. In this embodiment, the traveling gear 4 has two rotatable front wheels 5 and four rear wheels 6. The motor grader 1 can travel on the road surface RS using the front wheels 5 and rear wheels 6 of the traveling gear 4. Note that the traveling gear of the work machine is not limited to wheels, and may be tracks, etc.

The working machine 10 is supported by the vehicle body 2. As shown in Figures 1 and 2, the working machine 10 includes a main frame 11, a drawbar 12, a circle 13, a blade 14, a right blade lift cylinder 15, a left blade lift cylinder 16, a drawbar shift cylinder 17, a lifter 21, a lifter 22, a ball shaft 23, a blade shift cylinder 24, a blade tilt cylinder 25, and a circle rotation motor 26. The right blade lift cylinder 15, the left blade lift cylinder 16, and the drawbar shift cylinder 17 are three actuators that generate the movement of the drawbar 12. The right blade lift cylinder 15, the left blade lift cylinder 16, the drawbar shift cylinder 17, the blade shift cylinder 24, and the blade tilt cylinder 25 are hydraulic cylinders. The circle rotation motor 26 is a hydraulic motor. However, some of them do not have to be hydraulic cylinders or hydraulic motors. The right blade lift cylinder 15 and the left blade lift cylinder 16 are collectively referred to as blade lift cylinders or lift cylinders. In the following, the right blade lift cylinder 15 may be referred to as the right lift cylinder, and the left blade lift cylinder 16 may be referred to as the left lift cylinder. The right blade lift cylinder 15 and the left blade lift cylinder 16 are a pair of left and right lift cylinders that drive the draw bar 12 that supports the blade 14 in a generally vertical direction.

The main frame 11 is a support that supports each part of the work machine 10, and is made up of two partial frames that are pin-connected near the cab 3, allowing it to be articulated.

The blade 14 is supported so that it can shift and tilt relative to the drawbar 12, and performs excavation, soil transportation, shaping, etc. The circle 13 is a large gear with teeth on the inside, which holds the blade 14 and rotates the blade 14 360° in the direction of arrow A6 by the circle rotation motor 26. In this case, the blade 14 is attached to the drawbar 12 via the circle 13.

The drawbar 12 has an end restrained to be freely swingable and rotatable (hereinafter referred to as swingable) relative to the main frame 11 via a single ball axle 23, supports the circle 13, and receives a traction force. The ball axle 23 is also called a ball joint, and connects the main frame 11 and the drawbar 12. In this case, the drawbar 12 is attached to the main frame 11 of the motor grader 1. The drawbar 12 is also restrained to the main frame 11 by a single ball axle 23.

The right blade lift cylinder 15 has an intermediate portion supported by the main frame 11 via a lifter 21 so as to be freely swingable, and one end portion supported by the drawbar 12 so as to be freely swingable, and extends and retracts in the direction of the arrow A1. The left blade lift cylinder 16 has an intermediate portion supported by the main frame 11 via a lifter 22 so as to be freely swingable, and one end portion supported by the drawbar 12 so as to be freely swingable, and extends and retracts in the direction of the arrow A2. The drawbar shift cylinder 17 has one end supported by the main frame 11 so as to be freely swingable, and the other end supported by the drawbar 12 so as to be freely swingable, and extends and retracts in the direction of the arrow A3. The right blade lift cylinder 15, the left blade lift cylinder 16, and the drawbar shift cylinder 17 control the position and attitude of the drawbar 12, for example by further banking the drawbar 12 in the direction of the arrow A7.

The blade shift cylinder 24 has one end connected to the drawbar 12 and the other end supported by the blade 14, and extends and retracts in the direction of arrow A4 to feed the blade 14 laterally. The blade tilt cylinder 25 has one end connected to the drawbar 12 and the other end supported by the blade 14, and changes the cutting angle of the blade 14 in the rotational direction of arrow A5. The cutting angle is the angle between the cutting edge of the blade 14 and the road surface RS when the blade 14 comes into contact with the road surface (ground) RS.

[Control system configuration]
FIG. 3 shows an example of the configuration of a control system 300 of the motor grader 1 according to the embodiment. As shown in FIG. 3, the motor grader 1 includes a power source 201, a PTO (Power Take Off) 202, a traveling device 4, a hydraulic pump 203, a hydraulic control valve unit 204, a controller 100, an operator operation device 30, a position information detection unit 508, a work state determination device 400, and an external communication system 520. The controller 100 and the work state determination device 400 can be configured, for example, using a computer such as a microcomputer and its peripheral circuits and peripheral devices, and various functions are implemented by a combination of hardware such as a computer and software such as a program executed by the computer. The work state determination device 400 may be configured, for example, as one of the functions implemented by the controller 100. In FIG. 3, a solid line with two slashes "//" indicates the flow of an electric signal, a solid line indicates the flow of hydraulic oil, and a bold white line indicates the flow of mechanical power.

The power source 201 generates power for operating the work machine 1. Examples of the power source 201 include an internal combustion engine and an electric motor. Note that the power source 201 is not limited to an internal combustion engine or an electric motor. The power source 201 may be, for example, a so-called hybrid type device that combines an internal combustion engine, a generator motor, and a power storage device. The power source 201 may also have a configuration that does not have an internal combustion engine and combines a power storage device and a generator motor.

The PTO 202 transmits at least a portion of the power of the power source 201 to the hydraulic pump 203. The PTO 202 distributes the power of the power source 201 to the traveling device 4 and the hydraulic pump 203.

The traveling device 4 has, for example, a transmission, a drive shaft, brakes, rear wheels 6, etc. The traveling device 4 has, for example, a transmission with forward speed stages 1 to 8 and reverse speed stages 1 to 8. The smaller the speed stage number, the lower the speed. The front wheels 5 are driven, for example, by a hydraulic motor (not shown).

The operator control device 30 has a plurality of control levers, control pedals, control switches, etc. (not shown), and accepts input operations by the operator to the power source 201, the traveling device 4, the hydraulic control valve unit 204, etc., and outputs a signal indicating the content of the input operation to the controller 100. In this case, the operator control device 30 has a float operation SW (switch) 504 and an accumulator SW (switch) 507. Note that in this embodiment, the hydraulic control valve unit 204 is controlled via the controller 100, but is not limited to this. Also, the float operation SW 504 generates a left float operation signal and a right float operation signal that are in an on or off state. Also, the accumulator SW 507 generates an accumulator SW signal common to both the left and right that is in an on or off state.

The controller 100 receives output signals from the operator control device 30 and various sensors (not shown) and controls the hydraulic control valve unit 204. The controller 100 also exchanges predetermined control signals with control devices such as the power source 201 and the traveling device 4 (not shown). The controller 100 also outputs to the work state determination device 400 time information, which is a signal indicating the date and time, a vehicle stop signal or vehicle speed signal, which is a signal indicating the traveling/stopped state or traveling speed of the motor grader 1, a speed gear signal indicating the forward or reverse gear of the transmission, a left float operation signal and a right float operation signal indicating the on or off state of the float operation SW 504, and an accumulator SW signal indicating the on or off state of the accumulator SW 507.

The hydraulic control valve unit 204 receives the hydraulic oil output by the hydraulic pump 203, and under the control of the controller 100, controls the flow rate, pressure, and direction of the hydraulic oil supplied to each of the right blade lift cylinder 15, left blade lift cylinder 16, drawbar shift cylinder 17, blade shift cylinder 24, blade tilt cylinder 25, and circle rotation motor 26.

Figure 4 shows a part of the hydraulic control circuit in the hydraulic control valve unit 204. The hydraulic circuit 71 shown in Figure 4 controls the hydraulic oil supplied to the right blade lift cylinder 15 or the left blade lift cylinder 16 or discharged from the right blade lift cylinder 15 or the left blade lift cylinder 16. The hydraulic control valve unit 204 has two hydraulic circuits 71, and controls the right blade lift cylinder 15 and the left blade lift cylinder 16. Below, the hydraulic circuit 71 will be described using as an example a case where it controls the hydraulic pressure input and output to the right blade lift cylinder 15.

The right blade lift cylinder 15 includes a piston 151, a rod 152, a head side chamber 153, and a bottom side chamber 154. The right blade lift cylinder 15 includes a port B connected to the head side chamber 153 and a port A connected to the bottom side chamber 154. The right blade lift cylinder 15 is also provided with a right blade lift cylinder head pressure sensor 51 for measuring the hydraulic pressure in the head side chamber 153 and a right blade lift cylinder bottom pressure sensor 52 for measuring the hydraulic pressure in the bottom side chamber 154. Similarly, the left blade lift cylinder 16 is also provided with a left blade lift cylinder head pressure sensor 61 and a left blade lift cylinder bottom pressure sensor 62. In this embodiment, the right blade lift cylinder head pressure sensor 51, the right blade lift cylinder bottom pressure sensor 52, the left blade lift cylinder head pressure sensor 61, and the left blade lift cylinder bottom pressure sensor 62 are collectively referred to as a hydraulic pressure detection unit (hydraulic pressure detection unit 501 in FIG. 6).

The hydraulic circuit 71 includes a flow rate pressure control unit 711, directional control valves 712-714, and a hydraulic accumulator 715. Hydraulic oil stored in the tank 205 is supplied to the flow rate pressure control unit 711 via the hydraulic pump 203 and the operating valve 72. The flow rate pressure control unit 711 controls the flow rate and pressure of the hydraulic oil to supply it to the head side volume chamber 153 and the bottom side volume chamber 154. Port A of the right blade lift cylinder 15 is connected to the tank 205 via a directional control valve 713, and is connected to the hydraulic accumulator 715 via a directional control valve 714. Port B of the right blade lift cylinder 15 is connected to the tank 205 via a directional control valve 712.

The hydraulic circuit 71 controls the hydraulic oil supplied to ports A and B of the right blade lift cylinder 15 under the control of the controller 100 in response to the operation of a specific operating lever provided on the operator control device 30, for example. When the accumulator SW 507 is turned on, the hydraulic circuit 71 also connects port A of the right blade lift cylinder 15 to the hydraulic accumulator 715 under the control of the controller 100, and controls the hydraulic pressure in the bottom side chamber 154 to a constant pressure. In this case, the right blade lift cylinder 15 applies a constant pressure pressing force to the blade 14. In this embodiment, the work in this blade operating state is called blade accumulator work.

Also, when the float operation SW504 is turned on to generate a right float operation signal in the on state, under the control of the controller 100, the hydraulic circuit 71 connects ports A and B of the right blade lift cylinder 15 to the tank 205. In this case, the blade 14 lowers under its own weight and follows the ground. In this embodiment, work with the blade in this operating state is called float work.

Figure 5 shows a schematic example of the operation of the right blade lift cylinder 15 (or left blade lift cylinder 16) and the blade 14 during blade accumulator operation and float operation. In both blade accumulator operation and float operation, the blade 14 moves up and down following the ground, but in blade accumulator operation, a constant pressing force is applied to the blade 14 by the blade lift cylinder.

The position information detection unit 508 shown in FIG. 3 detects the position of the motor grader 1 using, for example, the Global Navigation Satellite System (GNSS), and outputs position information indicating the detection result (hereinafter, referred to as position information 5081).

The work state determination device 400 determines the work state, etc. of the motor grader 1 as described below. The work state determination device 400 transmits data indicating the determination result, etc. to a specified external server, etc. via the external communication system 520.

The external communication system 520 communicates with a specific external server, etc., using, for example, a mobile communication network, etc.

[Configuration of the work state determination device]
6 shows an example of the configuration of the work state determination device 400. The work state determination device 400 can be configured using a computer or the like as described above, and includes an acquisition unit 401, a work state determination unit 402, a threshold storage unit 403, and a storage/output unit 404 as a functional configuration configured by a combination of hardware such as a computer and software such as a program executed by the computer.

The acquisition unit 401 acquires the detection signals of the right blade lift cylinder head pressure sensor 51, the right blade lift cylinder bottom pressure sensor 52, the left blade lift cylinder head pressure sensor 61, and the left blade lift cylinder bottom pressure sensor 62 from the hydraulic detection unit 501. The acquisition unit 401 also acquires a vehicle stop signal or vehicle speed signal 502, a speed step signal 503, a float operation SW signal 504, an accumulator SW signal 507, position information 5081, and time information 509 from the controller 100. In this embodiment, one or more pieces of information acquired by the acquisition unit 401 are referred to as input information. The float operation SW signal 504 includes a left float operation SW signal 505 and a right float operation SW signal 506.

The work state determination unit 402, based on the input information acquired by the acquisition unit 401, determines a "travel state" indicating whether the motor grader 1 is stopped or traveling, a "work state" indicating whether work is being performed using the blade 14 or not, and a "work type" indicating the type of work being performed using the blade 14, as described below.

The threshold memory unit 403 stores reference values such as thresholds related to hydraulic pressure, hydraulic pressure change amount, time, speed, speed stage, etc., used by the work state determination unit 402 in various determinations.

The memory and output unit 404 stores the determination result by the work state determination unit 402, the time information, and the location information for a predetermined period of time. The memory and output unit 404 also transmits a time series of the determination result, the time information, and the location information for the predetermined period of time to a predetermined server, for example, via the external communication system 520 at each predetermined period of time. The transmission cycle can be, for example, every predetermined number of minutes, every predetermined number of hours, or every predetermined number of days.

[Operation of the work state determination device]
7 shows the flow of the determination process in the working state determination unit 402 as a state transition diagram. The working state determination unit 402 determines whether the "driving state" is a "stopped" state ST1 or a "driving" state ST2. If the driving determination condition is satisfied in the "stopped" state ST1, the state transitions from the "stopped" state ST1 to the "driving" state ST2. Also, if the driving determination condition is not satisfied in the "driving" state ST2, the state transitions from the "driving" state ST2 to the "stopped" state ST1. The initial state is the "stopped" state ST1.

The working state determination unit 402 also determines whether the "working state" is the "working" state ST3 or the "not working" state. The "not working" state is included in either the "stopped" state ST1 or the "driving" state ST2. If the working determination condition is met in the "driving" state ST2, the state transitions from the "driving" state ST2 to the "working" state ST3. If the working release determination condition is met in the "working" state ST3, and the driving determination condition is met, the state transitions from the "working" state ST3 to the "driving" state ST2. If the working release determination condition is met in the "working" state ST3, and the driving determination condition is not met, the state transitions from the "working" state ST3 to the "driving" state ST1.

Furthermore, the work state determination unit 402 determines the "work type" when the "work state" is the "working" state ST3. In this embodiment, the work state determination unit 402 determines (classifies) the "work type" as one of the following: "float work" state ST31, "blade accumulator work" state ST32, "trench digging work" state ST33, "land leveling/rolling work" state ST34, or "other work" state ST35. Here, with reference to Figures 8 to 12, examples of the operation of the work machine 10 in float work, blade accumulator work, trench digging work, and land leveling/rolling work will be described.

In this embodiment, the right lift cylinder pressure is the hydraulic pressure detected by the right blade lift cylinder head pressure sensor 51 minus the hydraulic pressure detected by the right blade lift cylinder bottom pressure sensor 52. The left lift cylinder pressure is the hydraulic pressure detected by the left blade lift cylinder head pressure sensor 61 minus the hydraulic pressure detected by the left blade lift cylinder bottom pressure sensor 62. The right lift cylinder pressure and the left lift cylinder pressure are collectively referred to as lift cylinder pressure. Furthermore, the lift cylinder pressure is not limited to the difference between the head and bottom, and may be the head pressure itself (also called head pressure) or the bottom pressure itself (also called bottom pressure). In that case, however, the reference value such as the threshold value will be adjusted.

Figure 8 shows an example of operation when the blade 14 is held in the air. In this case, the "traveling state" is "traveling" or "parked," and the "working state" is "not working." When held in the air, hydraulic pressure is supplied to the head side to prevent the working machine 10 from descending, and the head pressure rises and the bottom pressure falls (the lift cylinder pressure in this state is called the holding pressure). Therefore, the lift cylinder pressure rises compared to the value when the blade 14 is in contact with the ground (this is called the ground pressure). The value of the ground pressure ranges from the cylinder pressure when hydraulic pressure is supplied to the bottom side and the blade 14 is pressed against the ground by the cylinder, to the cylinder pressure when hydraulic pressure is supplied to the head side, the blade 14 is lifted, and the working machine 10 is about to leave the ground. The ground pressure is also affected by the action of the blade 14 receiving a reaction force from the ground and pushing up the cylinder.

FIG. 9 shows an example of the operation of the work machine 10 in float work. When the left and right float operation SW504 are turned on (operated), the lift cylinder pressure is controlled to release the holding pressure of the lift cylinder head, and the work is performed while the work machine 10 is grounded by its own weight. Therefore, the work can be performed by making the blade 14 follow the road surface. Therefore, the head pressure of the lift cylinder pressure decreases and the bottom pressure increases compared to just before the work machine 10 is grounded by its own weight. Note that float work is a work that does not require a relatively high ground pressure. The ground pressure here is the pressure that presses the blade 14 against the ground. In addition, the "ground pressure" when used as a reference value for comparison means that if the lift cylinder pressure is less than the "ground pressure", it is possible to determine that the blade 14 is in a state of grounding on the ground. In this embodiment, the "ground pressure" as a reference value for comparison corresponds to the value when no pressing force is generated by the cylinder and the blade 14 is grounded by its own weight.

Figure 10 shows an example of the operation of the work machine 10 during blade accumulator work. Because the blade 14 is in contact with the ground, the lift cylinder receives a reaction force, the bottom pressure increases, and the head pressure decreases. However, when the accumulator SW 507 is turned on (operated), a certain amount of pressing pressure is generated on the bottom side.

Figure 11 shows an example of the operation of the work machine 10 during trench digging work. Trench digging work involves digging a trench with one of the left or right ends of the blade 14 touching the ground. The lift cylinder on the side where the blade 14 is in contact with the ground receives a reaction force, causing the bottom pressure to increase and the head pressure to decrease. The head pressure on the side where the blade 14 is floating above the ground is increased by the application of holding pressure, and the bottom pressure decreases. For this reason, the difference between the left and right head pressures becomes large when excavating.

Figure 12 shows an example of the operation of the work machine 10 during ground leveling/spreading work. Ground leveling/spreading work involves bringing the entire lower end of the blade 14 (the cutting edge of the blade) into contact with the ground to level the ground and spread removed soil and sand. The blade 14 is pressed against the ground, generating a reaction force from the ground that is received by the left and right lift cylinders, decreasing the head pressure and increasing the bottom pressure.

FIG. 13 shows an example of the driving determination condition, the working determination condition, and the working release determination condition described with reference to FIG. 7.

The driving determination condition is a condition in which the vehicle is determined to be "driving" when the vehicle speed is greater than the "driving determination threshold" and is determined to be "stopped" when the vehicle speed is equal to or less than the "driving determination threshold". The "driving determination threshold" is a value indicating that the vehicle speed is greater than 0 (e.g., 1 km/h, etc.).

The in-work condition is that the device is determined to be in work if all of the following conditions (1) to (3) are met for a period of at least a first determination time. The first determination time is the time required for the input signal to stabilize, and can be set to, for example, about 0.5 seconds.

(1) The vehicle is moving forward. (2) The speed gear is 1 to 4. (3) The pressure in either the left or right lift cylinder is less than the "ground pressure", or the sum of the left and right lift cylinder pressures is less than the "operation judgment pressure".

If either the left or right lift cylinder pressure is less than the "ground contact pressure", it can be determined that the blade 14 is on the ground. However, even if neither the left nor right lift cylinder pressure is less than the "ground contact pressure", the blade 14 may still be in a ground contact state. Therefore, in this embodiment, the sum of the left and right lift cylinder pressures is compared with a predetermined reference value, the "work determination pressure", to recognize a state in which the blade 14 is on the ground without either the left or right lift cylinder pressure being less than the "ground contact pressure".

The in-work release determination condition is a condition for determining that the device is "not in work" if the following condition (1) is met for a period of time equal to or longer than the second determination time. The second determination time is the time required for the input signal to stabilize, and can be, for example, about one second.

(1) Both left and right lift cylinder pressures are equal to or greater than the "ground pressure" and the sum of the left and right lift cylinder pressure oil pressure changes is less than the "non-change threshold pressure" or both left and right lift cylinder pressures are greater than the "air retention threshold pressure." The sum of the left and right lift cylinder pressure oil pressure changes is the sum of the left lift cylinder pressure change and the right lift cylinder pressure change.

Here, the no-change determination threshold is a threshold for determining that the amount of change in hydraulic pressure per unit time has stabilized. The air-hold determination threshold pressure corresponds to a pressure value higher than the ground pressure, and corresponds to a value at which it can be determined that the blade 14 is held in the air, as shown in FIG. 8.

FIG. 14 shows an example of the judgment conditions (discrimination conditions) for each work type described with reference to FIG. 7.

The conditions for determining whether floating work is occurring are as follows: (1) to (2) all must be met to determine that "floating work is occurring."

(1) Either the left or right float activation switch 504 is on. (2) The gear is 1 to 8 (forward).

The blade accumulator operation determination condition is that "blade accumulator operation" is determined when all of the following conditions (1) to (3) are met.

(1) The pressure of either the left or right lift cylinder is less than the "ground pressure", or the sum of the left and right lift cylinder pressures is less than the "operation judgment pressure". (2) Blade accumulator SW507 is on. (3) The speed range is 1 to 4 (forward).

The trench digging work determination condition is that the work is determined to be "trench digging work" when all of the following conditions (1) to (3) are met.

(1) The pressure of either the left or right lift cylinder is less than the "ground pressure", or the sum of the left and right lift cylinder pressures is less than the "operation judgment pressure". (2) The difference between the left and right lift cylinder pressures is greater than or equal to the "trench digging judgment threshold". (3) The speed range is 1 to 3 (forward).

The trench digging determination threshold is a threshold at which it can be determined that the blade 14 is inclined to the left and right horizontal directions to an extent that is typically used in trench digging work, as shown in FIG. 11.

The conditions for determining whether ground leveling/rolling work is occurring are as follows: (1) to (3) all of the following conditions are met to determine that the work is "ground leveling/rolling work."

(1) The pressure of either the left or right lift cylinder is less than the "ground pressure", or the sum of the left and right lift cylinder pressures is less than the "work judgment pressure". (2) The difference between the left and right lift cylinder pressures is less than the "terrain leveling judgment threshold". (3) The speed gear is 1 to 4 (forward).

The ground leveling judgment threshold is a threshold at which it can be determined that the blade 14 is inclined horizontally to the left and right to a degree that is normally used in ground leveling/rolling work.

Next, an example of the operation of the work state determination device 400 will be described with reference to Figs. 15 and 16. The process shown in Fig. 15 is executed repeatedly at a predetermined cycle. The process shown in Fig. 16 is executed in step S107 of Fig. 15.

When the process shown in FIG. 15 is started, first, the acquisition unit 401 acquires input information (S101). Next, the work state determination unit 402 determines whether or not the driving determination condition is satisfied (S102). If the driving determination condition is satisfied (S102: YES), the work state determination unit 402 sets the "driving state" to "driving" (S103). Next, the work state determination unit 402 determines whether or not the "working state" is "not working" (S104). If the "working state" is "not working" (S104: YES), the work state determination unit 402 determines whether or not the working determination condition is satisfied continuously for a first determination time or more (S105). If the working determination condition is satisfied continuously for a first determination time or more (S105: YES), the work state determination unit 402 sets the "working state" to "working" (S106). Next, the work state determination unit 402 determines the "work type" (S107). After step S107, the work state determination unit 402 determines whether the work release determination condition is satisfied continuously for at least the second determination time (S108). If the work release determination condition is satisfied continuously for at least the second determination time (S108: YES), the work state determination unit 402 sets the "work state" to "not working" (S109). Next, the storage and output unit 404 outputs the "travel state", "work state", "work type", etc. (stored in a specified storage device or stored in a storage device and transmitted using the external communication system 520) (S110), and the process shown in FIG. 15 ends.

If the driving determination condition is not met in step S102 (S102: NO), the work state determination unit 402 sets the "driving state" to "stopped" (S111). Next, the work state determination unit 402 determines whether the "work state" is "not working" (S112). If the "work state" is "not working" (S112: YES), the memory and output unit 404 outputs the "driving state", "work state", "work type", etc. (S110), and the process shown in FIG. 15 ends.

If the "work state" is not "not working" in step S104 (S104: NO), or if the "work state" is not "not working" in step S112 (S112: NO), the work state determination unit 402 determines the "work type" (S107). Next, the process from step S108 onwards is executed.

If the in-work determination condition is not satisfied continuously for at least the first determination time in step S105 (S105: NO), or if the in-work release determination condition is not satisfied continuously for at least the second determination time in step S108 (S108: YES), the memory and output unit 404 outputs the "driving state", "work state", "work type", etc. (S110), and the process shown in FIG. 15 ends.

When the process shown in FIG. 16 is started, the work state determination unit 402 determines whether or not the float work determination condition is met (S201). If the float work determination condition is met (S201: YES), the work state determination unit 402 sets the "work type" to "float work" (S202) and ends the process shown in FIG. 16. If the float work determination condition is not met (S201: NO), the work state determination unit 402 determines whether or not the blade accumulator work determination condition is met (S203). If the blade accumulator work determination condition is met (S203: YES), the work state determination unit 402 sets the "work type" to "blade accumulator work" (S204) and ends the process shown in FIG. 16.

If the blade accumulator work determination condition is not met (S203: NO), the work state determination unit 402 determines whether or not the trench digging work determination condition is met (S205). If the digging work determination condition is met (S201: YES), the work state determination unit 402 sets the "work type" to "trench digging work" (S206) and ends the process shown in FIG. 16. If the trench digging work determination condition is not met (S205: NO), the work state determination unit 402 determines whether or not the leveling/rolling work determination condition is met (S207). If the leveling/rolling work determination condition is met (S207: YES), the work state determination unit 402 sets the "work type" to "leveling/rolling work" (S208) and ends the process shown in FIG. 16. If the ground leveling/rolling work determination condition is not met (S207: NO), the work status determination unit 402 sets the "work type" to "other work" (S209) and ends the process shown in FIG. 16.

According to the above operational example, the work state determination device 400 can determine the "travel state," "work state," and "work type."

In that case, the working state determination unit 402 determines that the working state of the blade 14 is in operation if it is determined that any of the multiple blade lift cylinders (hydraulic cylinders) is in a state where the blade 14 is in contact with the ground based on the hydraulic pressure detected by the hydraulic pressure detection unit 501 and the "ground pressure" (first reference pressure), or if it is determined that any of the multiple hydraulic cylinders is in a state where the blade 14 is in contact with the ground based on a total value (calculated value) based on the multiple hydraulic pressures detected by the hydraulic pressure detection unit 501 at the multiple blade lift cylinders (hydraulic cylinders) and a work determination pressure (second reference pressure) that is different from the "ground pressure" (first reference pressure). With this configuration, it is possible to appropriately determine whether or not the blade 14 is in operation. The total value may be replaced with another calculated value, such as the difference value of the multiple hydraulic pressures.

The working state determination unit 402 also determines that the working state of the blade 14 is not in operation if it is determined that none of the multiple blade lift cylinders (hydraulic cylinders) have the blade 14 in a state where it is in contact with the ground based on the hydraulic pressure detected by the hydraulic pressure detection unit 501 and the "ground pressure" (first reference pressure) and if the amount of change in the detected hydraulic pressure is smaller than the non-change determination threshold (first determination pressure), or if it is determined that none of the multiple blade lift cylinders (hydraulic cylinders) have the blade 14 in a state where it is in contact with the ground based on the hydraulic pressure detected by the hydraulic pressure detection unit 501 and the hollow retention determination threshold (third reference pressure) corresponding to a distance from the ground greater than the "ground pressure" (first reference pressure). With this configuration, it is possible to appropriately determine whether or not to release the working state.

In addition, when the work state determination unit 402 determines that work is in progress, if the difference between the multiple hydraulic pressures detected by the hydraulic pressure detection unit 501 in the multiple blade lift cylinders (hydraulic cylinders) is equal to or greater than the trench digging determination threshold (first determination threshold), it determines that the type of work being performed by the blade 14 is trench digging work. With this configuration, trench digging work can be appropriately determined.

In addition, when the work state determination unit 402 determines that work is in progress, if the difference between the multiple hydraulic pressures detected by the hydraulic pressure detection unit 501 in the multiple blade lift cylinders (hydraulic cylinders) is less than the ground leveling determination threshold (second determination threshold), it determines that the type of work being performed by the blade 14 is ground leveling or winding work. With this configuration, it is possible to appropriately determine whether the work is ground leveling or winding work.

Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to the above-mentioned embodiments, and includes design modifications within the scope of the gist of the present invention. In addition, part or all of the programs executed by the computer in the above-mentioned embodiments can be distributed via computer-readable recording media or communication lines.

<Additional Notes>
The working state determination device 400 described in the above embodiment can be understood, for example, as follows.

(1) The work state determination device 400 includes an acquisition unit that acquires the detection results of a hydraulic pressure detection unit that detects hydraulic pressure of multiple hydraulic cylinders that hydraulically drive a blade mounted on a work vehicle, and a work state determination unit that determines that the work state of the blade is in operation when it is determined that any of the multiple hydraulic cylinders is in a state where the blade is grounded based on the hydraulic pressure detected by the hydraulic pressure detection unit and a first reference pressure, or when it is determined that any of the multiple hydraulic cylinders is in a state where the blade is grounded based on a calculated value based on the multiple hydraulic pressures detected by the hydraulic pressure detection unit at the multiple hydraulic cylinders and a second reference pressure different from the first reference pressure.

(2) The working state determination device 400 is the working state determination device 400 of (1), and the working state determination unit determines that the working state of the blade is not working when it is determined that none of the multiple hydraulic cylinders has the blade grounded based on the hydraulic pressure detected by the hydraulic pressure detection unit and the first reference pressure, and the amount of change in the detected hydraulic pressure is smaller than the first determination pressure, or when it is determined that none of the multiple hydraulic cylinders has the blade grounded based on the hydraulic pressure detected by the hydraulic pressure detection unit and a third reference pressure corresponding to a distance from the ground greater than the first reference pressure.

(3) The work state determination device 400 is the work state determination device 400 of (1) or (2), and when the work state determination unit determines that the work is in progress, if the difference between the multiple hydraulic pressures detected by the hydraulic pressure detection unit in the multiple hydraulic cylinders is equal to or greater than a first determination threshold, the work type of the blade is trench digging work.

(4) The work state determination device 400 is a work state determination device 400 according to (1) to (3), and when the work state determination unit determines that the work is in progress and the difference between the multiple hydraulic pressures detected by the hydraulic pressure detection unit in the multiple hydraulic cylinders is less than a second determination threshold, the work type of the blade is determined to be ground leveling or rolling work.

(5) The working state determination device 400 is the working state determination device 400 of (1) to (4), and the multiple hydraulic cylinders are a pair of lift cylinders that drive the draw bar that supports the blade in the vertical direction. Note that in this disclosure, "driving the draw bar in the vertical direction" also includes driving the draw bar in the substantial vertical direction (roughly vertical direction) within a certain error range.

1...motor grader (work vehicle), 11...main frame, 12...drawbar, 14...blade, 15...right blade lift cylinder, 16...left blade lift cylinder, 17...drawbar shift cylinder, 23...ball shaft, 100...controller, 300...control system, 400...working state determination device, 401...acquisition unit, 402...working state determination unit, 403...threshold memory unit, 404...memory/output unit, 51...right blade lift cylinder head pressure sensor, 52...right blade lift cylinder bottom pressure sensor, 61...left blade lift cylinder head pressure sensor, 62...left blade lift cylinder bottom pressure sensor

Claims

an acquisition unit that acquires detection results of a hydraulic pressure detection unit that detects hydraulic pressures of a plurality of hydraulic cylinders that hydraulically drive a blade mounted on the work vehicle;
a working state determination unit that determines that the working state of the blade is in operation when it is determined that any of the plurality of hydraulic cylinders is in a state where the blade is in contact with the ground based on the hydraulic pressure detected by the hydraulic pressure detection unit and a first reference pressure, or when it is determined that any of the plurality of hydraulic cylinders is in a state where the blade is in contact with the ground based on a calculated value based on the plurality of hydraulic pressures detected by the hydraulic pressure detection unit at the plurality of hydraulic cylinders and a second reference pressure different from the first reference pressure;
A work state determination device comprising:
2. The work state determination device according to claim 1, wherein the work state determination unit determines that the work state of the blade is not in operation when it is determined that none of the multiple hydraulic cylinders has the blade grounded based on the hydraulic pressure detected by the hydraulic pressure detection unit and the first reference pressure and an amount of change in the detected hydraulic pressure is smaller than the first determination pressure, or when it is determined that none of the multiple hydraulic cylinders has the blade grounded based on the hydraulic pressure detected by the hydraulic pressure detection unit and a third reference pressure corresponding to a distance from the ground greater than the first reference pressure.
The work state determination device according to claim 1 or 2, wherein when the work state determination unit determines that the work is being performed and the difference between the multiple hydraulic pressures detected by the hydraulic pressure detection unit in the multiple hydraulic cylinders is equal to or greater than a first determination threshold, the work type of the blade is a trench digging work.
The work state determination device according to claim 3, wherein when the work state determination unit determines that work is being performed and the difference between the multiple hydraulic pressures detected by the hydraulic pressure detection unit in the multiple hydraulic cylinders is less than a second determination threshold, the work type of the blade is leveling or spreading work.
The work state determination device according to claim 4 , wherein the plurality of hydraulic cylinders are a pair of lift cylinders that drive a draw bar supporting the blade in a vertical direction.
A step of acquiring a detection result of a hydraulic pressure detection unit that detects hydraulic pressure of a plurality of hydraulic cylinders that hydraulically drive a blade mounted on the work vehicle;
determining that the working state of the blade is in operation when it is determined that any of the plurality of hydraulic cylinders is in a state where the blade is in contact with the ground based on the hydraulic pressure detected by the hydraulic pressure detection unit and a first reference pressure, or when it is determined that any of the plurality of hydraulic cylinders is in a state where the blade is in contact with the ground based on a calculated value based on the plurality of hydraulic pressures detected by the hydraulic pressure detection unit at the plurality of hydraulic cylinders and a second reference pressure different from the first reference pressure;
A working state determination method comprising:
Blade and
A plurality of hydraulic cylinders for hydraulically driving the blades;
a hydraulic pressure detection unit that detects hydraulic pressure of the plurality of hydraulic cylinders;
An acquisition unit that acquires a detection result of the hydraulic pressure detection unit;
a working state determination unit that determines that the working state of the blade is in operation when it is determined that any of the plurality of hydraulic cylinders is in a state where the blade is in contact with the ground based on the hydraulic pressure detected by the hydraulic pressure detection unit and a first reference pressure, or when it is determined that any of the plurality of hydraulic cylinders is in a state where the blade is in contact with the ground based on a calculated value based on the plurality of hydraulic pressures detected by the hydraulic pressure detection unit at the plurality of hydraulic cylinders and a second reference pressure different from the first reference pressure;
A work vehicle equipped with: