Working machine

Abstract

The present invention aims to provide a work machine capable of performing work with high precision by preventing the deterioration of speed responsiveness of a hydraulic cylinder driving a work device and preventing flapping or rotation of said hydraulic cylinder. Accordingly, the controller calculates a correction value for the target operating pressure of a flow control valve to bring the meter-out pressure of said hydraulic cylinder, measured while driving the hydraulic cylinder to perform a predetermined operation of the work device, into a range from a predetermined first lower limit value to a predetermined first upper limit value, and corrects the target operating pressure according to the correction value.

Description

Technology Field

[0001] The present invention relates to a work machine capable of machine control. Background Technology

[0002] Recently, there has been a growing demand for semi-automatic, automatic, and remote control of work machines such as hydraulic shovels, leading to the advancement of electronic control of work machines. One method of electronically controlling work machines is to control hydraulic actuators using electromagnetic valves. For example, a method is known in which a control valve for controlling hydraulic actuators, such as hydraulic cylinders and hydraulic motors, is operated by pilot pressure (operating pressure) generated by an electromagnetic valve.

[0003] In semi-automatic or automatic operation, for area-limiting control that moves the claw tip of a bucket to follow a predetermined target surface, it is important to control multiple hydraulic actuators with high precision at the target speed of each actuator under any load conditions or speeds. Here, in the electronic control of a working machine, a technique is known to improve excavation precision by correcting the data used for control while taking into account individual differences of the working machine (see Patent Document 1).

[0004] Patent Document 1 discloses an invention aimed at improving excavation precision in semi-automatic operation. The working device described in Patent Document 1 is equipped with a controller that stores data defining the relationship between the operating pressure and the operating speed of a hydraulic cylinder. The controller increases the current value of the current output to the electronic valve (electronic proportional control valve) that generates the operating pressure in steps. Based on the current value at which the hydraulic cylinder starts operation and the operating speed of the hydraulic cylinder when a current of a predetermined value is output to the electronic valve, the controller corrects the relationship between the operating pressure and the operating speed of the hydraulic cylinder in the data. Furthermore, the operating speed of the hydraulic cylinder has a meter flow rate, which is the flow rate of the operating fluid flowing at the inlet side of the hydraulic cylinder, and a meter opening, which is the opening of the control valve for controlling the meter flow rate, as factors. Prior art literature

[0005] Publication No. 2015 / 137525 The problem to be solved

[0006] However, in the correction of data defining the relationship between the operating pressure and the operating speed of the hydraulic cylinder based on the operating speed of the hydraulic cylinder with the meter-out opening and meter-out flow rate as factors in Patent Document 1, pressure loss (brake pressure) caused by the throttle of the meter-out opening is not taken into account, so even if the hydraulic cylinder is driven at the desired operating speed, there is a risk that the excavation precision will deteriorate due to deviations in the meter-out opening.

[0007] Specifically, if the pressure loss caused by the meter-out opening throttle is excessively large, the hydraulic cylinder is driven in a state where the brake functions excessively well, leading to a deterioration in fuel efficiency or the speed responsiveness of the hydraulic cylinder. On the other hand, if the pressure loss caused by the meter-out opening throttle is excessively small, the hydraulic cylinder is driven in a state where the brake does not engage well, resulting in a loss of operational stability of the hydraulic cylinder and causing flapping or slippage of the hydraulic cylinder.

[0008] The present invention has been made in consideration of the above problem, and its purpose is to provide a work machine capable of performing work with high precision by preventing the deterioration of the speed responsiveness of the hydraulic cylinder driving the work device and preventing flapping or rotation of the hydraulic cylinder. means of solving the problem

[0009] To achieve the above objective, the present invention relates to a working machine comprising: a vehicle body; a working device rotatably mounted on the vehicle body; a hydraulic cylinder for driving the working device; an operating device for operating the working device; a hydraulic pump; a flow control valve for controlling the flow rate of operating fluid supplied from the hydraulic pump to the hydraulic cylinder; an electronic valve for generating an operating pressure of the flow control valve; and a controller that calculates a target speed of the hydraulic cylinder based on the amount of operation of the operating device so as to limit the operating range of the working device to a target surface and above it, calculates a target operating pressure of the flow control valve based on the target speed, and controls the electronic valve according to the target operating pressure, wherein the working machine comprises a pressure sensor for measuring the meter-out pressure of the hydraulic cylinder, and the controller calculates a correction value for the target operating pressure to ensure that the meter-out pressure measured while driving the hydraulic cylinder to perform a predetermined operation of the working device falls within a range from a predetermined first lower limit value to a predetermined first upper limit value, and corrects the target operating pressure according to the correction value. does.

[0010] According to the present invention configured as described above, by correcting the target operating pressure of the flow control valve so that the meter-out pressure of the hydraulic cylinder driving the work device falls within a predetermined range, the deterioration of the speed responsiveness of the hydraulic cylinder driving the work device and the flapping or rotation of the hydraulic cylinder can be prevented, thereby making it possible to perform work with high precision. Effects of the invention

[0011] According to the present invention, by preventing the deterioration of the speed responsiveness of the hydraulic cylinder driving the work device and the flapping or rotation of the hydraulic cylinder, it becomes possible to perform work with high precision. Brief explanation of the drawing

[0012] FIG. 1 is a diagram showing the configuration of a hydraulic shovel related to a first embodiment of the present invention. FIG. 2 is a diagram showing the configuration of a hydraulic system mounted on a hydraulic shovel related to the first embodiment of the present invention. FIG. 3 is a figure showing the reference coordinate system of a hydraulic shovel related to the first embodiment of the present invention. FIG. 4 is a hardware configuration diagram of a control system mounted on a hydraulic shovel related to the first embodiment of the present invention. FIG. 5 is a figure showing an example of a display screen of a display device related to the first embodiment of the present invention. FIG. 6 is a functional block diagram of a controller related to the first embodiment of the present invention. Figure 7 is a figure showing an example of a trajectory when the leading edge of the bucket is MCed according to the target velocity vector after correction. Figure 8 is an opening diagram of the meter-out passage section of a flow control valve. FIG. 9 is a flowchart showing a learning process executed by a learning unit related to the first embodiment of the present invention. FIG. 10 is a figure showing a learning initiation posture and a learning initiation target surface related to a first embodiment of the present invention. FIG. 11 is a figure showing an example of a learning start posture screen related to the first embodiment of the present invention. FIG. 12 is a figure showing the time series change of the stored cylinder pressure in the learning process related to the first embodiment of the present invention. FIG. 13 is a figure showing a correction process related to the first embodiment of the present invention. Figure 14 is a diagram of a hydraulic system configuration when an open center system is adopted. FIG. 15 is a flowchart showing a learning process executed by a learning unit related to a second embodiment of the present invention. FIG. 16 is a figure showing a learning initiation posture related to a second embodiment of the present invention. FIG. 17 is a flowchart showing a learning process executed by a learning unit related to a third embodiment of the present invention. FIG. 18 is a figure showing a correction process related to a third embodiment of the present invention. FIG. 19 is a flowchart showing a learning process executed by a learning unit related to the fourth embodiment of the present invention. FIG. 20 is a flowchart illustrating a learning process executed by a learning unit related to the 6th embodiment of the present invention. FIG. 21 is a figure showing a correction process related to the 7th embodiment of the present invention. Specific details for implementing the invention

[0013] Hereinafter, embodiments of work machines related to the present invention will be described with reference to the drawings, using a hydraulic shovel as an example. In addition, in each drawing, equivalent elements are given the same reference numerals, and redundant descriptions are appropriately omitted.

[0014] [Example 1]

[0015] FIG. 1 is a side view of a hydraulic shovel related to a first embodiment of the present invention. In addition, in this embodiment, a hydraulic shovel with a bucket attached as an attachment (working tool) to the tip of a working device is described as an example, but the present invention can also be applied to a hydraulic shovel with an attachment other than a bucket.

[0016] As shown in FIG. 1, the hydraulic shovel (1) is composed of a vehicle body (1B) and a multi-joint work device (front work device) (1A) mounted on the vehicle body (1B). The vehicle body (1B) has a driving body (11) that is driven by left and right driving motors (hydraulic motors) and a swivel body (12) mounted on the driving body (11). The swivel body (12) swivels relative to the driving body (11) by a swivel motor (hydraulic motor). The pivot axis of the swivel body (12) is vertical when the hydraulic shovel (1) is stationary on a horizontal surface. A driver's cab (16) is provided in the swivel body (12).

[0017] The working device (1A) is configured to have a plurality of driving target members (boom (8), arm (9), and bucket (10)) connected to each rotate within a vertical plane. The base of the boom (8) is rotatably connected to the front of the pivot body (12) via a boom pin (91). The arm (9) is rotatably connected to the front end of the boom (8) via an arm pin (92), and the bucket (10) is rotatably connected to the front end of the arm (9) via a bucket pin (93). The boom (8) is driven by a boom cylinder (5), which is a hydraulic cylinder; the arm (9) is driven by an arm cylinder (6), which is a hydraulic cylinder; and the bucket (10) is driven by a bucket cylinder (7), which is a hydraulic cylinder. The hydraulic cylinder (5, 6, 7) comprises a cylinder tube in the shape of a tube with a bottom that is closed at one end, a head cover that blocks the opening at the other end of the cylinder tube, a cylinder rod that penetrates the head cover and is inserted into the cylinder tube, and a piston provided at the tip of the cylinder rod that divides the inside of the cylinder tube into a rod chamber and a bottom chamber.

[0018] A boom angle sensor (30) is mounted on the boom pin (91), an arm angle sensor (31) is mounted on the arm pin (92), a bucket angle sensor (32) is mounted on the bucket link (13), and a vehicle body inclination angle sensor (33) is mounted on the swivel body (12). The angle sensors (30, 31, 32) each detect the rotation angles (α, β, γ) (Fig. 3) of the boom (8), arm (9), and bucket (10), and output a signal indicating the detection result to the controller (40) (described later). The vehicle body inclination angle sensor (33) detects the vehicle body inclination angle (θ) (Fig. 3) of the swivel body (12) (vehicle body (1B)) relative to a reference plane (e.g., a horizontal plane) and outputs a signal indicating the detection result to the controller (40) (described later).

[0019] A rotating body (12) is provided with a pair of GNSS (Global Navigation Satellite System) antennas (hereinafter referred to as GNSS antennas) (14a, 14b). A controller (40) calculates the position and orientation of the rotating body (12) in a global coordinate system based on satellite signals (GNSS radio waves) from a plurality of positioning satellites received by the GNSS antennas (14a, 14b).

[0020] FIG. 2 is a diagram of a hydraulic system mounted on a hydraulic shovel (1). FIG. 2 shows the hydraulic circuits related to the boom cylinder (5), arm cylinder (6) and bucket cylinder (7), while the hydraulic circuits related to the driving motor and slewing motor are omitted from the illustration.

[0021] Electric operating lever devices (A1 to A3) are installed inside the driver's cabin (16). The electric operating lever devices (A1, A3) share an operating lever (B1) positioned on one side of the left and right of the driver's seat (not shown). When the electric operating lever device (A1) is operated by the operating lever (B1), the controller (40) operates the electronic valves (55a, 55b, 56a, 56b). By doing so, the boom cylinder (5) (boom (8)) is driven. When the electric operating lever device (A3) is operated by the operating lever (B1), the controller (40) operates the electronic valves (59a, 59b). By doing so, the bucket cylinder (7) (bucket (10)) is driven. The electric operating lever device (A2) has an operating lever (B2) positioned on the other side of the left and right of the driver's seat. When the electric operating lever device (A2) is operated by the operating lever (B2), the controller (40) operates the electronic valves (57a, 57b, 58a, 58b). By doing so, the arm cylinder (6) (arm (9)) is driven.

[0022] A pressure sensor (5a) is installed at the inlet / outlet port on the rod side of the boom cylinder (5), and a pressure sensor (5b) is installed at the inlet / outlet port on the bottom side of the boom cylinder (5). A pressure sensor (6a) is installed at the inlet / outlet port on the rod side of the arm cylinder (6), and a pressure sensor (6b) is installed at the inlet / outlet port on the bottom side of the arm cylinder (6). A pressure sensor (7a) is installed at the inlet / outlet port on the rod side of the bucket cylinder (7), and a pressure sensor (7b) is installed at the inlet / outlet port on the bottom side of the bucket cylinder (7).

[0023] The slewing body (12) is equipped with a prime mover engine (18), a first main pump (201), a second main pump (202), a third main pump (203), and a pilot pump (48). The main pumps (201, 202, 203) and the pilot pump (48) are driven by the engine (18) and discharge working fluid sucked from a tank. A pressure sensor (201b) is mounted on the discharge port of the first main pump (201), a pressure sensor (202b) is mounted on the discharge port of the second main pump (202), and a pressure sensor (203b) is mounted on the discharge port of the third main pump (203).

[0024] The first main pump (201) has a regulator (201a), the second main pump (202) has a regulator (202a), and the third main pump (203) has a regulator (201a). The main pumps (201, 202, 203) are variable displacement hydraulic pumps in which the discharge capacity (displacement volume) per revolution is controlled by the regulators (201a, 202a, 203a). In this embodiment, the main pumps (201, 202, 203) are swashplate type hydraulic pumps in which the discharge capacity is controlled by the tilting angle of the swashplate. The main pumps (201, 202, 203) discharge hydraulic fluid to drive a plurality of hydraulic actuators (boom cylinder (5), arm cylinder (6), bucket cylinder (7), etc.). The pilot pump (48) is a fixed-capacity hydraulic pump with a constant discharge capacity per revolution.

[0025] The regulators (201a, 202a, 203a) are driven by a hydraulic signal according to a target value of regulator pressure (hereinafter also referred to as target regulator pressure) (PPc201, PPc202, PPc203) calculated by the controller (40) based on the amount of operation of the electric operating lever devices (A1 to A3), thereby controlling the discharge capacity of the main pumps (201, 202, 203).

[0026] Specifically, the regulators (201a, 202a, 203a) each have a regulator solenoid valve (not shown). The controller (40) outputs an electrical signal (excitation current) according to the target regulator pressure to the regulator solenoid valve. By doing so, the regulator solenoid valve is actuated, and the regulator pressure that operates the swash plate is generated by the regulator solenoid valve. The regulator solenoid valve is an electronic proportional pressure reducing valve that generates a regulator pressure (pilot secondary pressure) according to a command from the controller (40) by reducing the discharge pressure (pilot primary pressure) of the pilot pump (48).

[0027] As the tilting angle (i.e., discharge capacity) of the swash plate changes due to the regulator pressure generated by the regulator electronic valve, the discharge flow rate of the main pump (201, 202, 203) changes. Accordingly, the discharge flow rate of the main pump (201, 202, 203) changes according to the target regulator pressure calculated by the controller (40).

[0028] The hydraulic system has a plurality of electronic valves (55a to 59b). The plurality of electronic valves (55a to 59b) generate an operating pressure that operates the flow control valves (D1 to D6) described later, according to a command (electric signal) from the controller (40). The plurality of electronic valves (55a to 59b) are electronic proportional pressure reducing valves that generate an operating pressure (pilot secondary pressure) according to the operating direction and amount of operation of the electric operating lever device (A1 to A3) by reducing the discharge pressure (pilot primary pressure) of the pilot pump (48).

[0029] A lock valve (39) is provided in the discharge pipe (170) of the pilot pump (48). The downstream side of the lock valve (39) in the discharge pipe (170) is branched into multiple sections and connected to solenoid valves (55a to 59b). The lock valve (39) in this embodiment is an electronic switching valve, and its solenoid is electrically connected to a position sensor of a gate lock lever (not shown) located in the driver's cab (16) of the slewing body (12). The position of the gate lock lever is detected by the position sensor, and a signal corresponding to the position of the gate lock lever is input to the lock valve (39) from the position sensor. When the position of the gate lock lever is in the locked position, the lock valve (39) is closed and the discharge pipe (170) is blocked, thereby blocking the supply of pilot pressure from the pilot pump (48) to the solenoid valves (55a to 59b). When the position of the gate lock lever is in the unlocked position, the lock valve (39) is opened and the discharge pipe (170) is opened, and pilot pressure is supplied from the pilot pump (48) to the solenoid valves (55a to 59b). When the discharge pipe (170) is closed, operation by the electric operating lever device (A1 to A3) is disabled, and operations such as excavation are prohibited.

[0030] The controller (40) generates an electric signal (excitation current) that drives the electronic valves (55a to 59b) according to the amount of operation and the direction of operation of the operating levers (B1 to B2) of the electric operating lever devices (A1 to A3), and outputs the signal to the electronic valves (55a to 59b) corresponding to the direction of operation of the operating levers (B1, B2). The hydraulic system is equipped with a control valve unit (15) that controls the flow of hydraulic fluid discharged from the main pumps (201, 202, 203) and supplied to the hydraulic cylinders (5 to 7). The control valve unit (15) is configured to include a plurality of flow control valves (D1 to D6).

[0031] The flow control valve (D1) (first flow control valve) controls the flow rate of the hydraulic fluid supplied from the first main pump (201) to the boom cylinder (5) according to the operation of the electric operating lever device (A1). The operating pressure generated by the electronic valves (55a, 55b) driven by the command of the controller (40) is input to the hydraulic pressure chambers (E1, E2) of the flow control valve (D1) via the pilot lines (C1, C2). The spool of the flow control valve (D1) is driven according to the operating pressure input to the hydraulic pressure chambers (E1, E2). By driving the spool of the flow control valve (D1), the supply direction and flow rate of the hydraulic fluid from the first main pump (201) to the boom cylinder (5) are controlled, and the boom cylinder (5) is driven.

[0032] The flow control valve (D2) (second flow control valve) controls the flow rate of the hydraulic fluid supplied from the second main pump (202) to the boom cylinder (5) according to the operation of the electric operating lever device (A1). The operating pressure generated by the electronic valves (55a, 55b) driven by the command of the controller (40) is input to the hydraulic chambers (E3, E4) of the flow control valve (D2) via the pilot lines (C3, C4). The spool of the flow control valve (D2) is driven according to the operating pressure input to the hydraulic chambers (E3, E4). By driving the spool of the flow control valve (D2), the supply direction and flow rate of the hydraulic fluid from the second main pump (202) to the boom cylinder (5) are controlled, and the boom cylinder (5) is driven.

[0033] The flow control valve (D3) (third flow control valve) controls the flow rate of the hydraulic fluid supplied from the third main pump (203) to the boom cylinder (5) according to the operation of the electric operating lever device (A1). The operating pressure generated by the electronic valves (56a, 56b) driven by the command of the controller (40) is input to the hydraulic chambers (E5, E6) of the flow control valve (D3) via the pilot lines (C5, C6). The spool of the flow control valve (D3) is driven according to the operating pressure input to the hydraulic chambers (E5, E6). By driving the spool of the flow control valve (D3), the supply direction and flow rate of the hydraulic fluid from the third main pump (203) to the boom cylinder (5) are controlled, and the boom cylinder (5) is driven.

[0034] In this way, the boom cylinder (5) is driven by controlling the flow rate of the hydraulic fluid discharged from the three main pumps (201, 202, 203) by the three flow control valves (D1, D2, D3). Additionally, when the controller (40) issues a command only to the electronic valves (56a, 56b) among the electronic valves (55a, 55b, 56a, 56b), the boom cylinder (5) is driven only by the hydraulic fluid discharged from the third main pump (203).

[0035] The flow control valve (D4) (fourth flow control valve) controls the flow rate of the hydraulic fluid supplied from the second main pump (202) to the arm cylinder (6) according to the operation of the electric operating lever device (A2). The operating pressure generated by the electronic valves (57a, 57b) driven by the command of the controller (40) is input to the hydraulic chambers (E7, E8) of the flow control valve (D4) via the pilot lines (C7, C8). The spool of the flow control valve (D4) is driven according to the operating pressure input to the hydraulic chambers (E7, E8). By driving the spool of the flow control valve (D4), the supply direction and flow rate of the hydraulic fluid from the second main pump (202) to the arm cylinder (6) are controlled, and the arm cylinder (6) is driven.

[0036] The flow control valve (D5) (the fifth flow control valve) controls the flow rate of the hydraulic fluid supplied from the first main pump (201) to the arm cylinder (6) according to the operation of the electric operating lever device (A2). The operating pressure generated by the electronic valves (58a, 58b) driven by the command of the controller (40) is input to the hydraulic chambers (E9, E10) of the flow control valve (D5) via the pilot lines (C9, C10). The spool of the flow control valve (D5) is driven according to the operating pressure input to the hydraulic chambers (E9, E10). By driving the spool of the flow control valve (D5), the supply direction and flow rate of the hydraulic fluid from the first main pump (201) to the arm cylinder (6) are controlled, and the arm cylinder (6) is driven.

[0037] In this way, the arm cylinder (6) is driven by controlling the flow rate of the hydraulic fluid supplied from the two main pumps (201, 202) by the two flow control valves (D4, D5). Additionally, when the controller (40) issues a command only to the electronic valves (57a, 57b) among the electronic valves (57a, 57b, 58a, 58b), the arm cylinder (6) is driven only by the hydraulic fluid discharged from the second main pump (202).

[0038] The flow control valve (D6) (the 6th flow control valve) controls the flow rate of the hydraulic fluid supplied from the first main pump (201) to the bucket cylinder (7) according to the operation of the electric operating lever device (A3). The operating pressure generated by the electronic valves (59a, 59b) driven by the command of the controller (40) is input to the hydraulic chambers (E11, E12) of the flow control valve (D6) via the pilot lines (C11, C12). The spool of the flow control valve (D6) is driven according to the operating pressure input to the hydraulic chambers (E11, E12). By driving the spool of the flow control valve (D6), the supply direction and flow rate of the hydraulic fluid from the first main pump (201) to the bucket cylinder (7) are controlled, and the bucket cylinder (7) is driven. In this way, the bucket cylinder (7) is driven by controlling the flow rate of the working fluid discharged from the first main pump (201) by the flow control valve (D6).

[0039] FIG. 3 is an explanatory diagram of the method for calculating the bucket tip position. The posture of the work device (1A) can be defined based on the shovel reference coordinate system shown in FIG. 3. The shovel reference coordinate system of FIG. 3 is a coordinate system set based on the pivot body (12). In the shovel reference coordinate system, the origin is set at the center axis of the boom pin (91), the Z-axis is set parallel to the pivot center axis of the pivot body (12) (in the direction directly above the pivot body (12), and the X-axis is set in a direction orthogonal to the Z-axis (in front of the pivot body (12). Hereinafter, the angle of inclination of the boom (8) with respect to the X-axis is described as the boom angle (α), the angle of inclination of the arm (9) with respect to the boom (8) is described as the arm angle (β), and the angle of inclination of the bucket (10) with respect to the arm (9) is described as the bucket angle (γ). In addition, the angle of inclination of the vehicle body (1B) (turning body (12)) with respect to the horizontal plane (reference plane), that is, the angle formed by the horizontal plane (reference plane) and the X-axis, is described as the vehicle body angle of inclination (θ).

[0040] The boom angle (α) is detected by the boom angle sensor (30), the arm angle (β) by the arm angle sensor (31), the bucket angle (γ) by the bucket angle sensor (32), and the vehicle body inclination angle (θ) by the vehicle body inclination angle sensor (33). The boom angle (α) is minimized when the boom (8) is raised to the upper limit (the boom cylinder (5) is in the maximum extended state) and is maximized when the boom (8) is lowered to the lower limit (the boom cylinder (5) is in the maximum retracted state). The arm angle (β) is minimized when the arm cylinder (6) is in the maximum retracted state and is maximized when the arm cylinder (6) is in the maximum extended state. The bucket angle (γ) is minimized when the bucket cylinder (7) is in the maximum retracted state (state of FIG. 3) and is maximized when the bucket cylinder (7) is in the maximum extended state.

[0041] The position of the tip of the bucket (10) in the shovel reference coordinate system (hereinafter referred to as the tip position (Pb)) is represented by the following (Equation 1) and (Equation 2), with Xbk as the X-direction position and Zbk as the Z-direction position.

[0042] Xbk=L1cos(α)+L2cos(α+β)+L3cos(α+β+γ)···(Equation 1)

[0043] Zbk=L1sin(α)+L2sin(α+β)+L3sin(α+β+γ)···(Equation 2)

[0044] Here, L1 is the length from the center axis of the boom pin (91) connecting the swivel body (12) and the boom (8) to the center axis of the arm pin (92) connecting the boom (8) and the arm (9). L2 is the length from the center axis of the arm pin (92) to the center axis of the bucket pin (93) connecting the arm (9) and the bucket (10). L3 is the length from the center axis of the bucket pin (93) to the tip position of the bucket (10) (e.g., the claw end of the bucket (10)) (Pb).

[0045] Referring to FIG. 4, a control system (21) that performs machine control (MC) and machine guidance (MG) will be described. FIG. 4 is a hardware configuration diagram of a control system (21) mounted on a hydraulic shovel (1).

[0046] The controller (40) is equipped with an MC function that intervenes in the operator's operation under certain conditions and limits the operation of the work device (1A) when at least one of the electric operating lever devices (A1 to A3) is operated. The MC includes "area limiting control" executed when arm operation by the electric operating lever device (A2) or boom operation by the electric operating lever device (A1), and "stop control" executed when boom lowering operation by the electric operating lever device (A1) or bucket operation by the electric operating lever device (A3).

[0047] Area limit control is also called "ground leveling control." While area limit control is being executed, at least one of the boom cylinder (5), arm cylinder (6), and bucket cylinder (7) is controlled so that the work device (1A) does not excavate the area below the excavation target surface (St) (see FIG. 3). In area limit control, the operation of the work device (1A) is controlled so that the tip of the bucket (10) moves along the excavation target surface (St) by arm operation or boom operation. For example, when arm operation is performed, the controller (40) gives a command to raise the boom or lower the boom so that the velocity vector of the tip of the bucket (10) in a direction perpendicular to the excavation target surface (St) becomes zero. Additionally, the controller (40) commands arm pulling or arm pushing so that when boom operation is performed, the velocity vector of the front end of the bucket (10) in a direction perpendicular to the excavation target surface (St) becomes zero. By doing so, the trajectory of the front end of the bucket (10) caused by the arm movement or boom movement, which is a rotational movement, is corrected into a straight trajectory that follows the excavation target surface (St).

[0048] Stop control is a control that stops the boom lowering operation or bucket operation so that the tip of the bucket (10) does not enter an area below the excavation target surface (St). In stop control, the controller (40) slows down the boom lowering operation or bucket operation as the tip of the bucket (10) approaches the excavation target surface (St).

[0049] In addition, in this embodiment, the control point of the working device (1A) during MC is set to the claw end of the bucket (10) of the hydraulic shovel (1), but the control point can be changed to a point on the front part of the working device (1A) other than the claw end of the bucket (10). For example, the control point may be set to the bottom surface of the bucket (10) or the outermost part of the bucket link (13). In addition, the point on the bucket (10) closest to the excavation target surface (St) may be set as the control point. That is, the control point may change depending on the situation.

[0050] In the MC, there is "automatic control," in which the operation of the work device (1A) is controlled by the controller (40) when the electric operating lever devices (A1 to A3) are not operated, and "semi-automatic control," in which the operation of the work device (1A) is controlled by the controller (40) only when the electric operating lever devices (A1 to A3) are operated. Additionally, the MC is also called "intervention control" because control by the controller (40) intervenes in the operator's operation.

[0051] Additionally, the control system (21) performs a process to display the positional relationship between the excavation target surface (St) and the work device (1A) (e.g., bucket (10)) on the display device (53), as shown in FIG. 5, for example, as an MG.

[0052] As shown in FIG. 4, the control system (21) has a controller (40), an attitude detection device (50) connected to the controller (40) and outputting a signal to the controller (40), a target surface setting device (51), a vehicle body position detection device (14), an electric operating lever device (A1 to A3), an external input device (96), pressure sensors (5a to 7b), and a temperature sensor (19). Additionally, the control system (21) has a display device (53) connected to the controller (40) and controlled based on a signal from the controller (40), regulators (201a, 202a, 203a), and electronic valves (55a to 59b).

[0053] The attitude detection device (50) has a boom angle sensor (30), an arm angle sensor (31), a bucket angle sensor (32), and a vehicle body inclination angle sensor (33). These angle sensors (30, 31, 32, 33) acquire information regarding the attitude of the hydraulic shovel (1) and output a signal according to the information. That is, the angle sensors (30, 31, 32, 33) function as attitude sensors that detect the attitude of the work device (1A), that is, the attitude of a plurality of driving target members (boom (8), arm (9), and bucket (10)) constituting the work device (1A). In addition, the angle sensors (30, 31, 32) may employ a potentiometer that acquires, for example, boom angle (α), arm angle (β), and bucket angle (γ) as information regarding the attitude and outputs a signal (voltage) according to the acquired angles. Additionally, the vehicle body inclination angle sensor (33) may employ an IMU (Inertial Measurement Unit) that acquires angular velocity and acceleration of three orthogonal axes as information regarding the attitude of the turning body (12), calculates the vehicle body inclination angle (θ) based on this information, and outputs a signal indicating the vehicle body inclination angle (θ) to the controller (40).

[0054] Additionally, the calculation of the vehicle body inclination angle (θ) may be performed by the controller (40) based on the output signal of the IMU. Furthermore, the angle sensors (30-32) may each be replaced with a sensor (such as an IMU) that measures the inclination angle relative to a reference plane or a sensor that detects the stroke of a hydraulic cylinder (5-7).

[0055] The target surface setting device (51) is an input device including an MC controller capable of outputting information regarding the excavation target surface, such as location information of the excavation target surface and inclination angle information with respect to the reference plane (horizontal plane) of the excavation target surface, as a command signal to the controller (40). For example, the target surface setting device (51) is connected to an external terminal (not shown) that stores three-dimensional data of the excavation target surface defined in a global coordinate system (absolute coordinate system), and the three-dimensional data of the excavation target surface is input from the external terminal via a touch panel, which is an input device including an MC controller. In addition, the input of the excavation target surface to the controller (40) via the target surface setting device (51) may be performed manually by an operator.

[0056] The vehicle body position detection device (14) includes a pair of GNSS antennas (14a, 14b), calculates the position of the vehicle body (1B) (turning body (12)) and the orientation of the vehicle body (1B) (turning body (12)), and outputs the calculation result to the controller (40).

[0057] The external input device (96) is an input device that is operated by an operator and outputs an input signal according to the operation to the controller (40). The external input device (96) is, for example, a capacitive touch sensor provided on the display screen of the display device (53). Additionally, the external input device (96) may be equipped with a plurality of switches and levers.

[0058] FIG. 5 is a diagram showing an example of a display screen of a display device (53). As shown in FIG. 5, the display device (53) displays various display images on the display screen based on a display control signal from the controller (40). The display device (53) is, for example, a touch panel type liquid crystal monitor and is installed in the driver's cabin (16). The controller (40) displays a display image on the display screen of the display device (53) as an MG function, showing the positional relationship between the excavation target surface (St) and the work device (1A) (for example, the bucket (10)). In the example shown in the drawing, an image showing the excavation target surface (St) and the bucket (10) is displayed, and the distance from the excavation target surface (St) to the tip of the bucket (10) is displayed as the target surface distance (H1). The target surface distance (H1) takes a positive value in the upward direction and a negative value in the downward direction relative to the excavation target surface (St). Additionally, the display image shown in FIG. 5 can be displayed on the display device (53) regardless of whether a mode for executing the MC is set by a mode switching switch (not shown) operated by the operator. The operator can operate the work device (1A) by referring to this display image.

[0059] The controller (40) is composed of a computer equipped with a processing unit (41) such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), and DSP (Digital Signal Processor), non-volatile memory (42) such as ROM (Read Only Memory), flash memory, and hard disk drive, volatile memory (43) called RAM (Random Access Memory), an input interface (44), an output interface (45), and other peripheral circuits. This hardware works together to run software and realize multiple functions. Additionally, the controller (40) may be composed of one computer or multiple computers. Furthermore, as the processing unit (41), an ASIC (application specific integrated circuit), an FPGA (Field Programmable Gate Array), etc., may be used.

[0060] Various data, such as programs capable of executing various operations and threshold values, are stored in the non-volatile memory (42). That is, the non-volatile memory (42) is a memory medium (memory device) capable of reading programs that realize the functions of the present embodiment. The volatile memory (43) is a memory medium (memory device) that temporarily stores the results of operations by the processing device (41) and signals input from the input interface (44). The processing device (41) is a device that executes operations by expanding the program stored in the non-volatile memory (42) to the volatile memory (43), and performs a predetermined operation processing on the data received from the input interface (44), the non-volatile memory (42), and the volatile memory (43) according to the program.

[0061] The input interface (44) converts signals input from various devices (attitude detection device (50), target surface setting device (51), vehicle body position detection device (14), electric operating lever device (A1-A3), external input device (96), pressure sensors (5a-7b, 201b, 202b, 203b), and temperature sensor (19)) into data that can be processed by the processing device (41). Additionally, the output interface (45) generates an output signal based on the calculation result from the processing device (41) and outputs the signal to various devices (regulators (201a, 202a, 203a), electronic valves (55a-59b), and display device (53)).

[0062] The discharge capacity of the main pump (201-203) changes as the controller (40) controls the regulators (201a-203a). As the controller (40) controls the electronic valves (55a-59b), the spools of the flow control valves (D1-D6) operate, and the hydraulic cylinders (5-7) operate. As the controller (40) controls the display device (53), a predetermined image is displayed on the display screen of the display device (53).

[0063] -Controller Functions-

[0064] With reference to FIG. 6, details regarding the function of the controller (40) will be explained. FIG. 6 is a functional block diagram of the controller (40). The controller (40) functions as a control amount calculation unit (141), attitude calculation unit (142), target surface calculation unit (143), target speed calculation unit (144), target pressure calculation unit (145), corrected target pressure calculation unit (146), valve command calculation unit (147), learning unit (149), and display control unit (150) by executing a program stored in a non-volatile memory (42). The target pressure calculation unit (145), corrected target pressure calculation unit (146), and valve command calculation unit (147) function as an electronic valve control unit (148) that controls hydraulic cylinders (5, 6, 7), which are hydraulic actuators, by controlling electronic valves (55a to 59b).

[0065] The operation amount calculation unit (141) calculates the target value of the operation pressure generated by the electronic valves (55a to 59b) (hereinafter also referred to as the operation amount operation pressure) (Pi0(PiBM12U0, PiBM3U0, PiBM12D0, PiBM3D0, PiAM1C0, PiAM2C0, PiAM1D0, PiAM2D0, PiBKC0, PiBKD0)) based on the operation signal (operation amount and operation direction) of the electric operation lever device (A1). When a boom lifting operation is performed by the electric operation lever device (A1), the operation amount calculation unit (141) calculates the target value of the operation pressure generated by the electronic valve (55a) (PiBM12U0) and the target value of the operation pressure generated by the electronic valve (56a) (PiBM3U0). The operation amount calculation unit (141) calculates the target value (PiBM12D0) of the operation pressure generated by the electronic valve (55b) and the target value (PiBM3D0) of the operation pressure generated by the electronic valve (56b) when the boom lowering operation is performed by the electric operation lever device (A1).

[0066] The operation amount calculation unit (141) calculates the target value of the operation pressure generated by the electronic valve (57a) and the target value of the operation pressure generated by the electronic valve (58a) when the arm pulling (arm crowd) operation is performed by the electric operation lever device (A2). The operation amount calculation unit (141) calculates the target value of the operation pressure generated by the electronic valve (57b) and the target value of the operation pressure generated by the electronic valve (58b) when the arm pushing (arm dump) operation is performed by the electric operation lever device (A2).

[0067] The operation amount calculation unit (141) calculates the target value (PiBKC0) of the operation pressure generated by the electronic valve (59a) when the bucket pulling (bucket crowd) operation is performed by the electric operation lever device (A3). The operation amount calculation unit (141) calculates the target value (PiBKD0) of the operation pressure generated by the electronic valve (59b) when the bucket pushing (bucket dump) operation is performed by the electric operation lever device (A3).

[0068] The attitude calculation unit (142) calculates the attitude of the work device (1A) in the shovel reference coordinate system (local coordinate system) and the leading edge position (Pb) of the bucket (10) based on the attitude information (angle information) detected by the attitude detection device (50) and the dimension information (L1, L2, L3) of the work device (1A) stored in the non-volatile memory (42). The leading edge position (Pb(Xbk, Zbk)) of the bucket (10) can be calculated by (Equation 1) and (Equation 2) as previously described. Additionally, if the attitude of the work device (1A) and the leading edge position of the bucket (10) in the global coordinate system are required, the attitude calculation unit (142) converts the coordinates of the shovel reference coordinate system into the coordinates of the global coordinate system based on the position and orientation of the turning body (12) in the global coordinate system detected by the vehicle body position detection device (14).

[0069] The target surface calculation unit (143) sets the excavation target surface (St) based on information from the target surface setting device (51). Specifically, the target surface calculation unit (143) calculates the position information of the excavation target surface (St) based on information from the target surface setting device (51) and stores the calculation result in the volatile memory (43). The target surface calculation unit (143) calculates the cross-sectional shape (see FIG. 3) obtained by cutting the excavation target surface provided as 3D data via the target surface setting device (51) into a plane (operation plane of the work device) on which the work device (1A) moves, as a 2D excavation target surface (St).

[0070] In addition, in FIG. 3, there is only one excavation target surface (St), but there may be multiple excavation target surfaces (St). In the case where there are multiple excavation target surfaces (St), the target surface calculation unit (143) sets the one closest to the tip of the bucket (10), the one located vertically below the tip of the bucket (10), or an arbitrarily selected one as the excavation target surface (St) to be calculated.

[0071] The target speed calculation unit (144) calculates the target speed of each hydraulic cylinder (5, 6, 7) so that, in area limit control (grounding control), the work device (1A) does not excavate beyond the target excavation surface (St) and below the target excavation surface (St). The target speed calculation unit (144) calculates the target speed of each hydraulic cylinder (5, 6, 7) based on the calculation result from the attitude calculation unit (142) and the calculation result from the operation amount calculation unit (141).

[0072] Referring to FIG. 7, the method for calculating the target speed during area limit control will be explained in detail. FIG. 7 is a figure showing an example of the trajectory of the tip of the bucket (10) when the tip of the bucket (10) is controlled as the target speed vector (Vca) after correction. In the description provided here, the Xt axis and the Yt axis are set as shown in FIG. 7. The Xt axis is an axis parallel to the excavation target surface (St), and the Yt axis is an axis perpendicular to the excavation target surface (St).

[0073] The target speed calculation unit (144) calculates the first target speed of each hydraulic cylinder (5, 6, 7) based on the operating amount operating pressure (Pi0(PiBM12U0, PiBM3U0, PiBM12D0, PiBM3D0, PiAM1C0, PiAM2C0, PiAM1D0, PiAM2D0, PiBKC0, PiBKD0)) of the electronic valves (55a to 59b) calculated by the operating amount calculation unit (141).

[0074] The target speed calculation unit (144) calculates the target speed vector (Vc) of the front end of the bucket (10) shown in FIG. 7 based on the primary target speed of each hydraulic cylinder (5, 6, 7), the front end position (Pb) of the bucket (10) calculated by the attitude calculation unit (142), and the dimensional information (L1, L2, L3, etc.) of the work device (1A) stored in the non-volatile memory (42).

[0075] The target speed calculation unit (144) calculates the second target speed by correcting the first target speed of the necessary hydraulic cylinders among the hydraulic cylinders (5, 6, 7) so that the component (Vcy) (velocity component in the Yt-axis direction) perpendicular to the excavation target surface (St) in the target speed vector (Vc) of the front end of the bucket (10) approaches 0 (zero) as the target surface distance (H1), which is the distance between the front end of the bucket (10), approaches 0 (zero). By doing so, the target speed vector (Vc) of the front end of the bucket (10) is converted into the corrected target speed vector (Vca). When the target surface distance (H1) is 0 (zero), the target speed vector (Vca) consists only of the component (Vcx) (velocity component in the Xt-axis direction) parallel to the excavation target surface (St). For this reason, in area limit control, the tip of the bucket (10) is held above or above the excavation target surface (St) so that the tip of the bucket (10) does not intrude into an area below the excavation target surface (St). Hereinafter, control that converts (corrects) the velocity vector of the tip of the bucket (10) in this manner is also described as direction change control.

[0076] Direction change control may be executed by a combination of boom lifting or boom lowering and arm dump, or by a combination of boom lifting or boom lowering and arm dump. In either case, when the target speed vector (Vc) includes a downward component (Vcy<0) approaching the excavation target surface (St), the target speed calculation unit (144) calculates the target speed of the boom cylinder (5) in the boom lifting direction that eliminates the downward component. Conversely, when the target speed vector (Vc) includes an upward component (Vcy>0) moving away from the excavation target surface (St), the target speed calculation unit (144) calculates the target speed of the boom cylinder (5) in the boom lowering direction that eliminates the upward component.

[0077] In addition, when a mode is set in which area limit control (area control) is not performed by the mode switching switch (not shown), the target speed calculation unit (144) does not perform correction on the primary target speed of each hydraulic cylinder (5-7) according to the operation of the electric operating lever device (A1-A3).

[0078] In this way, the target speed calculation unit (144) calculates the target speed, which is the target value of the extension speed / retraction speed of the hydraulic cylinders (5, 6, 7), based on the calculation results of the manipulation amount calculation unit (141) and the attitude calculation unit (142).

[0079] The target pressure calculation unit (145) calculates the target spool opening of the flow control valves (D1 to D6) based on the detection results of the pressure sensors (5a to 7b, 201b to 203b) and the target speed of each hydraulic cylinder (5, 6, 7) calculated by the target speed calculation unit, and converts the target spool opening into a target operating pressure (Pi1(PiBM12U1, PiBM3U1, PiBM12D1, PiBM3D1, PiAM1C1, PiAM2C1, PiAM1D1, PiAM2D1, PiBKC1, PiBKD1)) based on the spool opening table and outputs it.

[0080] In this embodiment, the target pressure calculation unit (145) calculates the target spool opening on the meter-out side of the flow control valves (D1 to D6) based on the detection results of the pressure sensors (5a to 7b, 201b to 203b) and the target speed of each hydraulic cylinder (5, 6, 7) calculated by the target speed calculation unit, and converts the target spool opening on the meter-out side into a target operating pressure (Pi1(PiBM12U1, PiBM3U1, PiBM12D1, PiBM3D1, PiAM1C1, PiAM2C1, PiAM1D1, PiAM2D1, PiBKC1, PiBKD1)) based on the target opening table on the meter-out side of the flow control valves (D1 to D6) and outputs it.

[0081] Referring to FIG. 8, an example of the opening characteristics of the meter-out passage portion of the flow control valves (D1 to D6) will be described. FIG. 8 is an opening diagram of the meter-out passage portion of the flow control valves (D1 to D6) and shows the relationship between the operating pressure input to the hydraulic chambers (E1, E3, E5, E7, E9, E11) of the flow control valves (D1 to D6) and the opening area of ​​the meter-out passage portion of the flow control valves (D1 to D6). As shown in FIG. 8, as the operating pressure generated by the electronic valves (55a to 59a) increases, the opening area of ​​the meter-out passage portion of the flow control valves (D1 to D6) increases. An opening characteristic table (To) defining the relationship between the operating pressure and the opening area of ​​the flow control valves (D1 to D6) is stored in the non-volatile memory (42) of the controller (40).

[0082] The target pressure calculation unit (145) calculates the target operating pressure (Pi1(PiBM12U1, PiBM3U1, PiBM12D1, PiBM3D1, PiAM1C1, PiAM2C1, PiAM1D1, PiAM2D1, PiBKC1, PiBKD1)), which is the target value of the operating pressure, based on the meter-out target opening area (Aout(Aout_Bm1U, Aout_Bm3U, Aout_Bm1D, Aout_Bm3D, Aout_Am1C, Aout_Am2C, Aout_Am1D, Aout_Am2D, Aout_BkC, Aout_BkD)), by referring to the opening characteristic table (To).

[0083] The target pressure calculation unit (145) calculates the target flow rate (Q201, Q202, Q203) of each main pump (201, 202, 203) from the sum of the target flow rates on the meter side of each hydraulic cylinder (5-7) assigned to each main pump (201, 202, 203).

[0084] In the non-volatile memory (42), a regulator pressure table is stored in advance that defines the relationship between the target flow rate (Q201, Q202, Q203) of the main pump (201, 202, 203) and the target regulator pressure of the regulator (201a, 202a, 203a). The regulator pressure table is determined for each main pump (201, 202, 203).

[0085] The target pressure calculation unit (145) calculates the target regulator pressure (PPc201, PPc202, PPc203) based on the target flow rate (Q201, Q202, Q203) of the main pump (201, 202, 203) calculated by referring to the regulator pressure table.

[0086] The correction target pressure calculation unit (146) reads the correction value obtained through the learning processing of the learning unit (149) described later. Based on the read correction value and the target operating pressure (Pi1) calculated by the target pressure calculation unit (145), it calculates and outputs the correction target pressure (Pi2). Details of the correction processing in the correction target pressure calculation unit (146) will be described later.

[0087] The relationship between the opening area of ​​the flow control valves (D1 to D6) and the operating pressure generated by the electronic valves (55a to 59b) is subject to a deviation from the opening characteristic table (To) due to manufacturing errors of the flow control valves (D1 to D6). Manufacturing errors of the flow control valves (D1 to D6) include machining errors of the spool of the flow control valves (D1 to D6), deviations in the spring constant of the spring (centering spring) for holding the spool in a neutral position, and machining errors of the valve casing that holds the spool slidably. Furthermore, in the direction change control of the area limit control, there are cases where it is executed by a combination of boom lifting or boom lowering and arm crowding, and cases where it is executed by a combination of boom lifting or boom lowering and arm dumping. Consequently, the precision of the area limit control is particularly deteriorated due to a deviation (individual difference) from the opening characteristic table (To) caused by manufacturing errors of the flow control valves corresponding to the boom or arm.

[0088] In this embodiment, in order to suppress the deterioration of precision in area limit control due to deviation (individual difference) from the opening characteristic table (To) caused by manufacturing error of the flow control valve (D3) corresponding to the boom lifting operation among the flow control valves (D1 to D6), the learning unit (149) learns the relationship between the opening area of ​​the meter-out passage portion of the flow control valve (D3) and the operating pressure generated by the electronic valve (56a). Based on the learning result, the learning unit (149) refers to the opening characteristic table (To) and corrects the target operating pressure (PiBM3U1) calculated based on the target spool opening, thereby suppressing the deterioration of precision in area limit control due to deviation from manufacturing error.

[0089] In order to learn the relationship between the opening area of ​​the meter-out passage of the flow control valve (D3) and the operating pressure generated by the electronic valve (56a), the load pressure on the meter-out side of the hydraulic cylinder (5) is measured.

[0090] In this embodiment, the load pressure on the meter-out side of the hydraulic cylinder (5) is related to the opening area of ​​the meter-out passage of the flow control valve (D3) and the operating pressure generated by the electronic valve (56a). As the operating pressure generated by the electronic valve (56a) increases, the opening area of ​​the meter-out passage of the flow control valve (D3) becomes larger.

[0091] If the opening area of ​​the meter-out passage of the flow control valve (D3) increases, the pressure loss (brake pressure) caused by the throttle of the meter-out opening decreases, and the load pressure on the meter-out side of the hydraulic cylinder (5) decreases.

[0092] Conversely, as the operating pressure generated by the electronic valve (56a) decreases, the opening area of ​​the meter-out passage of the flow control valve (D3) becomes smaller. When the opening area of ​​the meter-out passage of the flow control valve (D3) becomes smaller, the pressure loss (brake pressure) caused by the throttle of the meter-out opening increases, and the load pressure on the meter-out side of the hydraulic cylinder (5) increases.

[0093] Therefore, by measuring the load pressure on the meter-out side of the hydraulic cylinder (5), the pressure loss (brake pressure) caused by the throttle can be measured, and the relationship between the opening area of ​​the meter-out passage of the flow control valve (D3) and the operating pressure generated by the electronic valve (56a) can be learned. In addition, as a method for measuring the pressure loss (brake pressure) caused by the throttle, in addition to the method of directly detecting the load pressure on the meter-out side of the hydraulic cylinder (5), there is a method of multiplying the load pressure on the meter-in side of the hydraulic cylinder (5) by the hydraulic pressure area ratio of the hydraulic cylinder (5).

[0094] Referring to FIG. 9, the flow of the learning process of the flow control valve (D3) executed by the learning unit (149) will be described. FIG. 9 is a flowchart showing the learning process of the flow control valve (D3) executed by the learning unit (149). When the external input device (96) is operated by an operator and a command to execute the learning process is input from the external input device (96), the learning unit (149) starts the learning process (step S101).

[0095] In step S101, the learning unit (149) reads the learning start posture data and the learning start target surface data connected to the learning of the flow control valve (D3) from the non-volatile memory (42).

[0096] FIG. 10 is a diagram showing a learning start position and a learning start target surface corresponding to a flow control valve (D3). In the non-volatile memory (42), learning start position data and learning start target surface data that define the learning start position shown in FIG. 10 are stored.

[0097] The learning start posture data includes a target range (lower limit and upper limit) that satisfies the target angle of the boom angle (α), a target range (lower limit and upper limit) that satisfies the target angle of the arm angle (β), and a target range (lower limit and upper limit) that satisfies the target angle of the bucket angle (γ), and the learning start target surface data includes a target range (lower limit and upper limit) in the Z-axis direction of the shovel reference coordinate system of the working device (1A) of the excavation target surface (St), and a target angle (lower limit and upper limit) between the excavation target surface (St) and the X-axis of the shovel reference coordinate system of the working device (1A).

[0098] In this embodiment, as shown in FIG. 10, to set the starting posture and target plane for horizontal pulling, the arm angle (β) of the learning starting posture data is set to the angle at which the arm cylinder (6) is maximally retracted, and the bucket angle (γ) is set to the target angle of 0 degrees. The learning starting target plane data is set to be parallel to the X-axis of the shovel reference coordinate system of the working device (1A), and the target range in the Z-axis direction is set so that the claw tip of the bucket (10) moves in the air. Additionally, the target angle of the boom angle (α) is the angle of the boom angle (α) when the arm angle (β) and the bucket angle (γ) satisfy the above target range and the claw tip of the bucket (10) coincides with the target plane, and the target range is set from the target angle of the boom angle (α).

[0099] In step S101, when the reading of the learning start posture data and the learning start target surface data is completed, the process proceeds to step S102. In step S102, as shown in FIG. 9, the display control unit (150) displays a learning start posture screen (53a) (see FIG. 11) on the display device (53). As shown in FIG. 11, the learning start posture screen (53a) displays a message "Please adjust the posture of the work device to the target range" urging the operator to perform an operation to set the posture of the work device (1A) to the learning start posture.

[0100] In step S102 of FIG. 9, when the learning start posture screen (53a) is displayed on the display device (53), the processing proceeds to step S103. In step S103, a determination is made as to whether the learning start conditions (learning start posture, learning start target screen, MC execution mode setting) are satisfied.

[0101] The determination of the learning start posture is a determination of whether the posture of the work device (1A) is a learning start posture. If each of the current boom angle (α), arm angle (β), and bucket angle (γ) is within the target range, the learning unit (149) determines that the posture of the work device (1A) is a learning start posture, and if any of the current boom angle (α), arm angle (β), and bucket angle (γ) is outside the target range, the learning unit (149) determines that the posture of the work device (1A) is not a learning start posture.

[0102] The determination of the learning start target surface is a determination of whether the excavation target surface (St) is a learning start target surface. If the excavation target surface (St) is within the target range defined in the learning start target surface data, the learning unit (149) determines that the excavation target surface (St) is a learning start target surface, and if the excavation target surface (St) is outside the target range defined in the learning start target surface data, the learning unit (149) determines that the excavation target surface (St) is not a learning start target surface.

[0103] The determination of the MC execution mode setting is a determination of whether the MC is set to an execution mode. If the MC is set to an execution mode by a mode switching switch operated by the operator, the learning unit (149) determines that the MC is set to an execution mode, and if the MC is not set to an execution mode by a mode switching switch operated by the operator, the learning unit (149) determines that the MC is not set to an execution mode.

[0104] In step S103, if all learning start conditions (learning start posture, learning start target surface, and MC execution mode settings) are determined to be positive, the processing proceeds to step S104. The determination of the learning start conditions (learning start posture, learning start target surface, and MC execution mode settings) in step S103 is repeated at a predetermined control cycle until a positive determination is made.

[0105] In step S103, if the determination of the learning start condition is positive, the display control unit (150) displays an operation instruction screen on the display device (53). On the operation instruction screen, an operation instruction is displayed saying, "Please operate the arm operation lever to the pull side." When the operation instruction screen is displayed in step S103, the processing proceeds to step S104.

[0106] In step S104, when the electric operating lever device (A2) is operated by the operator toward the arm pulling side, learning processing is initiated, and while the electric operating lever device (A2) is being operated, area limit control is executed, and the operation of the work device (1A) is controlled so that the front end of the bucket (10) moves along the excavation target surface (St).

[0107] The learning unit (149) measures the load pressure on the meter-out side of the hydraulic cylinder (5) when area limit control is executed and the boom (8) is driven in the lifting direction. Additionally, the load pressure on the meter-out side of the hydraulic cylinder (5) is also referred to as cylinder pressure below. The learning unit (149) stores the measured cylinder pressure and the time. Here, the stored cylinder pressure is detected by the pressure sensor (5a).

[0108] FIG. 12 is a figure showing the relationship between the time stored at the time of measurement of the cylinder pressure and the cylinder pressure. In step S104, the learning unit (149) calculates the minimum value (Pmin) (hereinafter also referred to as minimum cylinder pressure) and the maximum value (Pmax) (hereinafter also referred to as maximum cylinder pressure) of the cylinder pressure based on the stored time and the cylinder pressure measured using the pressure sensor (5a), and proceeds to step S105 for processing.

[0109] In step S105, the learning unit (149) determines whether the minimum cylinder pressure (Pmin) calculated in step S104 is greater than or equal to a predetermined minimum threshold value (Pm1) of the cylinder pressure. Additionally, the minimum threshold value (Pm1) of the cylinder pressure is the lower limit value when a target range (lower limit and upper limit value) satisfying the target value is set, wherein the cylinder pressure determined based on a tabletop calculation or an experiment using a prototype, based on the flow rate passing through the flow control valve (D3) during area limit control and the previously stored opening characteristics, is set as the target value.

[0110] In step S105, if it is determined that the minimum cylinder pressure (Pmin) is less than the minimum threshold value (Pm1) of the cylinder pressure, the learning unit (149) proceeds to step S107.

[0111] In step S107, the learning unit (149) obtains a correction value (Pic) that lowers the operating pressure by subtracting the correction value (Pic) of the operating pressure. For example, if the initial value of the correction value (Pic) is set to 1.00, in order to lower the operating pressure, 0.01 is subtracted from the initial value to make the correction value (Pic) 0.99.

[0112] The learning unit (149) outputs the acquired correction value (Pic) to the correction target pressure calculation unit and returns the processing to step S102. That is, when measuring the next cylinder pressure, the target operating pressure (PiBM3U1) is corrected in the correction target pressure calculation unit (146), and the correction target operating pressure (PiBM3U2) is output to the valve command calculation unit (147). In addition, the correction method in the correction target pressure calculation unit (146) will be described later.

[0113] In step S105, if it is determined that the minimum cylinder pressure (Pmin) is greater than the minimum threshold value (Pm1) of the cylinder pressure, the learning unit (149) proceeds to step S106.

[0114] In step S106, the learning unit (149) determines whether the maximum cylinder pressure (Pmax) calculated in step S104 is less than or equal to a predetermined maximum threshold value (Pm2) of the cylinder pressure. Additionally, the maximum threshold value (Pm2) of the cylinder pressure is the upper limit value when a target range (lower limit and upper limit value) is set by setting the cylinder pressure as the target value based on a tabletop calculation or an experiment using a starter, based on the flow rate passing through the flow control valve (D3) during area limit control and the opening characteristics stored in advance.

[0115] In step S106, if it is determined that the maximum cylinder pressure (Pmax) is greater than the maximum threshold value (Pm2) of the cylinder pressure, the learning unit (149) proceeds to step S108.

[0116] In step S108, the learning unit (149) obtains a correction value (Pic) that increases the operating pressure by adding a correction value (Pic) of the operating pressure. For example, if the initial value of the correction value (Pic) is set to 1.00, in order to increase the operating pressure, 0.01 is added to the initial value to make the correction value (Pic) 1.01.

[0117] The learning unit (149) outputs the acquired correction value (Pic) to the correction target pressure calculation unit and returns the processing to step S102. That is, when measuring the next cylinder pressure, the target operating pressure (PiBM3U1) is corrected in the correction target pressure calculation unit (146), and the correction target operating pressure (PiBM3U2) is output to the valve command calculation unit (147). In addition, the correction method in the correction target pressure calculation unit (146) will be described later.

[0118] In step S106, if it is determined that the maximum cylinder pressure (Pmax) is less than the maximum threshold value (Pm2) of the cylinder pressure, the learning unit (149) proceeds to step S109. In step S109, the learning unit (149) stores the correction value (Pic) of the operating pressure and terminates the processing shown in the flowchart of FIG. 9. Additionally, the display control unit (150) displays on the display device (53) that the learning processing has been terminated.

[0119] In this way, the learning unit (149) measures the cylinder pressure while the area limit control is being executed during the learning process and obtains a correction value (Pic) of the operating pressure when it enters the range of pressure threshold values ​​(Pta) (minimum threshold value of cylinder pressure (Pm1), maximum threshold value of cylinder pressure (Pm2)). The obtained correction value (Pic) is used in the correction process.

[0120] In addition, in this embodiment, as shown in FIG. 12, the measured cylinder pressure becomes smaller than the minimum threshold value (Pm1) of the cylinder pressure immediately after the area limit control is executed and the boom lifting operation is terminated, when the electric operating lever device (A2) is operated by the operator toward the arm pulling side. When the measured cylinder pressure is smaller than the minimum threshold value (Pm1) of the cylinder pressure, the flow proceeding from step S105 to step S107 in FIG. 9 is repeated.

[0121] Therefore, in this embodiment, a threshold value (Vta) is set for the secondary target speed calculated by the target speed calculation unit (144), and the cylinder pressure is measured when the secondary target speed of the hydraulic cylinder (5) is greater than or equal to the threshold value (Vta). That is, by measuring the cylinder pressure excluding the cylinder pressure immediately after the area limit control is executed and near the end of the boom lifting operation, the repetition of the flow proceeding from incorrect step S105 to step S107 is prevented. In addition, the condition for initiating the measurement of the cylinder pressure does not have to be a threshold value for the secondary target speed, and it is sufficient if the cylinder pressure can be measured excluding the cylinder pressure immediately after the area limit control is executed and near the end of the boom lifting operation.

[0122] The valve command calculation unit (147) calculates an electrical signal based on the target operating pressure (Pi1(PiBM12U1, PiBM3U1, PiBM12D1, PiBM3D1, PiAM1C1, PiAM2C1, PiAM1D1, PiAM2D1, PiBKC1, PiBKD1)) and the corrected target pressure (Pi2) calculated by the target pressure calculation unit (145), and outputs the calculated electrical signal to the corresponding electronic valves (55a to 59b). Additionally, the valve command calculation unit (147) calculates an electrical signal based on the target regulator pressure (PPc(PPc201, PPc202, PPc203)) calculated by the target pressure calculation unit (145), and outputs the calculated electrical signal to the regulator electronic valves of the corresponding regulators (201a to 203a).

[0123] By the electrical signal (excitation current) output from the valve command calculation unit (147), the solenoid of the electronic valve (55a to 59b) is energized, thereby operating the electronic valve (55a to 59b), and the operating pressure (pilot pressure) acting on the flow control valve (D1 to D6) is controlled to the target operating pressure (Pi1) calculated by the target pressure calculation unit (145). As a result, the operating speed of the hydraulic cylinder (5 to 7) is controlled to the target speed. Additionally, by the electrical signal (excitation current) output from the valve command calculation unit (147), the solenoid of the regulator electronic valve of the regulator (201a to 203a) is energized, thereby operating the regulator electronic valve, and the regulator pressure (pilot pressure) acting on the hydraulic part of the regulator (201a to 203a) is controlled to the target regulator pressure (PPc) calculated by the target pressure calculation unit (145). Accordingly, the discharge flow rate of the main pumps (201 to 203) is controlled to the target flow rate (Q201, Q202, Q203).

[0124] Correction processing is described with reference to FIG. 13. FIG. 13 illustrates correction processing performed by a correction target pressure calculation unit (146). Here, the target operating pressure (PiBM3U1) is calculated by the target pressure calculation unit (145), and the correction value (Pic) is obtained from the learning unit (149). The correction target pressure calculation unit (146) receives the target operating pressure (PiBM3U1) calculated by the target pressure calculation unit (145) and reads the correction value (Pic) obtained from the learning unit (149). In this embodiment, since learning processing regarding the flow control valve (D3) is performed, in the correction processing, the target pressure calculation unit (145) outputs the target operating pressure (PiBM3U1) corresponding to the flow control valve (D3) to the correction target pressure calculation unit (146). Additionally, the target operating pressure output from the target pressure calculation unit (145) to the valve command calculation unit (147) is the target operating pressure excluding the target operating pressure (PiBM3U1) (Pi1(PiBM12U1, PiBM12D1, PiBM3D1, PiAM1C1, PiAM2C1, PiAM1D1, PiAM2D1, PiBKC1, PiBKD1)).

[0125] The corrected target pressure calculation unit (146) calculates the corrected target operating pressure (PiBM3U2) by multiplying the target operating pressure (PiBM3U1) and the correction value (Pic), and outputs it to the valve command calculation unit (147).

[0126] As described above, the controller (40) related to the present embodiment calculates the target spool opening on the meter-out side of the flow control valve (D1 to D6) based on the target speed of the hydraulic cylinder (5 to 7) and the detection result of the pressure sensors (5a to 7b, 201b to 203b). Then, the controller (40) calculates the target operating pressure based on the target spool opening by referring to the opening characteristic table (To).

[0127] Additionally, in the learning unit (149), learning processing regarding the flow control valve (D3) is performed, and correction processing of the target operating pressure is performed using the correction value obtained in the learning processing, and the corrected target operating pressure is calculated.

[0128] The controller (40) controls the electronic valves (55a to 59b) so that the operating pressure generated by the electronic valves (55a to 59b) becomes the target operating pressure and the corrected target operating pressure.

[0129] In this way, by calculating the target operating pressure and the corrected target operating pressure, the target opening area corresponding to the load pressure can be determined even if the load pressure (hydraulic load condition) of the hydraulic cylinder changes. Furthermore, by performing learning processing and correction processing, the target operating pressure corresponding to the deviation of the manufacturing error of the flow control valve (D3) can be determined. Therefore, even if an open center system is adopted in the hydraulic system, the hydraulic cylinders (5-7) can be operated with high precision using the calculated target flow rate (target speed), thereby suppressing the deterioration of the precision of the area limit control caused by the deviation of the manufacturing error of the flow control valve (D3). As a result, operations by MC, such as area limit control, can be performed with high precision.

[0130] In addition, the above learning process is preferably performed when the spool of the flow control valve (D3) is replaced, or when the spool stroke has changed to some extent from the characteristics at the time of factory shipment due to the aging deterioration of the flow control valve (D3). By doing so, MC can be performed with high precision over a long period.

[0131] According to the first embodiment described above, it has the following functional effects.

[0132] (1) The target pressure calculation unit (145) calculates the target value (target operating pressure) (Pi1) of the operating pressure generated by the electronic valves (55a to 59b) based on the opening characteristic table (To), the target spool opening (Aout in this embodiment), and the operating pressure (Pi0). The target pressure calculation unit (145) related to this embodiment outputs PiBM3U1 among the target operating pressures (Pi1) to the corrected target pressure calculation unit (146).

[0133] The corrected target pressure calculation unit (146) calculates the corrected target operating pressure (PiBM3U2) based on the target operating pressure (PiBM3U1) and the correction value (Pic) obtained through the learning processing of the learning unit (149). The valve command calculation unit (147) controls the electronic valves (55a to 59b) based on the corrected target operating pressure (PiBM3U2) and the target operating pressure (Pi1) excluding the target operating pressure (PiBM3U1).

[0134] The learning unit (149) measures the cylinder pressure of the flow control valve (D3) while the area limit control is being executed, and performs a learning process to obtain a correction value (Pic) of the operating pressure when the measured cylinder pressure (minimum cylinder pressure (Pmin), maximum cylinder pressure (Pmax)) falls within the range of a predetermined pressure threshold value (Pta).

[0135] In the learning process, by measuring the cylinder pressure (minimum cylinder pressure (Pmin), maximum cylinder pressure (Pmax)) and obtaining a correction value (Pic) of the operating pressure so that it falls within the range of a predetermined pressure threshold value (Pta), the pressure drop (brake pressure) caused by the throttle of the meter-out opening can be brought into the target range.

[0136] According to this configuration, the influence of manufacturing errors of the flow control valve (D3) is reduced through learning and correction, and the opening characteristics of the flow control valve that were previously used in the prototype are reproduced, thereby allowing the flow control valve to be controlled. As a result, the claw tip (control point) of the bucket (10) can be moved with high precision in area limit control, etc.

[0137] In addition, the hydraulic system may be a closed center system or, as shown in FIG. 14, an open center system. When the controller (40) related to this embodiment wants to operate the hydraulic cylinders (5-7) at a predetermined target flow rate (target speed), it calculates the target opening area using an orifice formula that considers the target flow rate (target speed) and the load pressure of the hydraulic cylinders (5-7). Therefore, even if an open center system is adopted in the hydraulic system, the hydraulic cylinders (5-7) can be operated at the target flow rate (target speed) regardless of whether the load is light or heavy.

[0138] In this way, according to the present embodiment, deviations in the operation of hydraulic cylinders caused by individual differences in working machines are suppressed regardless of the configuration of the hydraulic system, thereby providing a working machine capable of working with high precision.

[0139] (2) The learning unit (149) sets as one of the conditions for initiating learning processing at least the position of the work device (1A) being the learning start position and the excavation target surface (St) being the learning start target surface. By doing so, the learning unit (149) can appropriately obtain a correction value (Pic), and the correction target pressure calculation unit (146) can correct the target operating pressure (Pi1) with high precision.

[0140] In the first embodiment, a work machine (1) comprises a vehicle body (1B), a work device (1A) rotatably mounted on the vehicle body (1B), a hydraulic cylinder (5) for driving the work device (1A), an operating device (A1) for operating the work device (1A), a hydraulic pump (203), a flow control valve (D3) for controlling the flow rate of hydraulic fluid supplied from the hydraulic pump (203) to the hydraulic cylinder (5), electronic valves (56a, 56b) for generating an operating pressure of the flow control valve (D3), and a controller (40) that calculates a target speed of the hydraulic cylinder (5) based on the amount of operation of the operating device (A1) so that the operating range of the work device (1A) is limited to above and above a target surface (St), calculates a target operating pressure of the flow control valve (D3) based on the target speed, and controls the electronic valves (56a, 56b) according to the target operating pressure, wherein the meter-out pressure of the hydraulic cylinder (5) The controller (40) is equipped with pressure sensors (5a, 5b) for measurement, and calculates a correction value (Pic) of the target operating pressure to bring the measured meter-out pressure into a range from a predetermined first lower limit value (Pm1) to a predetermined first upper limit value (Pm2) while driving the hydraulic cylinder (5) to perform a predetermined operation on the work device (1A), and corrects the target operating pressure according to the correction value (Pic).

[0141] In addition, the controller (40) in the first embodiment calculates a correction value (Pic) to decrease the target operating pressure when the minimum value (Pmin) of the meter-out pressure measured while the work device (1A) is performing the predetermined operation falls below the first lower limit value (Pm1), and calculates a correction value (Pic) to increase the target operating pressure when the maximum value (Pmax) of the meter-out pressure measured while the work device (1A) is performing the predetermined operation exceeds the first upper limit value (Pm2), thereby correcting the target operating pressure by increasing or decreasing the target operating pressure according to the correction value (Pic).

[0142] According to the first embodiment configured as described above, by correcting the target operating pressure of the flow control valve (D3) so that the meter-out pressure of the hydraulic cylinder (5) driving the work device (1A) falls within a predetermined range (Pm1 to Pm2), the deterioration of the speed responsiveness of the hydraulic cylinder (5) driving the work device (1A) and flapping or rotation of the hydraulic cylinder (5) can be prevented, so it is possible to perform work with high precision.

[0143] In addition, the pressure sensor (5b) in the first embodiment detects the meter pressure of the hydraulic cylinder (5), and the controller (40) calculates the measured value of the meter-out pressure by multiplying the meter pressure detected by the pressure sensor (5b) by the hydraulic pressure area ratio of the hydraulic cylinder (5). By doing so, it becomes possible to measure the meter-out pressure of the hydraulic cylinder (5) even if the pressure sensor (5a) for detecting the meter-out pressure of the hydraulic cylinder (5) is not provided.

[0144] [Example 2]

[0145] Regarding the second embodiment of the present invention, the differences from the first embodiment will be explained. In the first embodiment, learning processing is performed for a horizontal pulling motion, whereas in this embodiment, learning processing is performed for a boom lifting motion only.

[0146] FIG. 15 is a flowchart showing a learning process executed by a learning unit (149) related to the present embodiment, and FIG. 16 shows a learning start posture related to the present embodiment.

[0147] In this embodiment, as shown in FIG. 16, the arm cylinder (6) and bucket cylinder (7) are at their maximum extension, and the boom angle at which the work device (1A) does not touch the ground is stored as the boom lifting-only learning start position, and the cylinder pressure during the boom lifting-only operation is measured, and a correction value is obtained by comparing the measured cylinder pressure with a threshold value.

[0148] Referring to FIG. 15, a learning process regarding a flow control valve (D3) by a boom lifting operation is described. When an external input device (96) is operated by an operator and a command to execute the learning process is input from the external input device (96), the learning unit (149) starts the learning process (step S201).

[0149] In step S201, when the reading of the boom lifting single learning start posture data is completed, proceed to step S202.

[0150] In step S202, the display control unit (150) displays a boom lifting solo learning start posture as shown in FIG. 16 on the display device (53) and proceeds the processing to step S203.

[0151] In step S203, the learning unit (149) determines whether the posture of the work device (1A) is a learning start posture. If each of the current boom angle (α), arm angle (β), and bucket angle (γ) is within the target range defined in the boom lifting-only learning start posture data, the learning unit (149) determines that the posture of the work device (1A) is a learning start posture and proceeds to step S204.

[0152] If at least one of the current boom angle (α), arm angle (β) and bucket angle (γ) is outside the target range defined in the boom lifting single learning start posture data, the learning unit (149) determines that the posture of the work device (1A) is not a learning start posture. The learning start condition determination process of step S203 is repeated at a predetermined control cycle until a positive determination is made.

[0153] In step S203, if the learning start condition determination process is positive, the display control unit (150) displays an operation instruction screen on the display device (53). On the operation instruction screen, an operation instruction is displayed saying, "Please operate the boom operation lever toward the lifting side." When the operation instruction screen is displayed in step S203, the processing proceeds to step S204.

[0154] In step S204, when the electric operating lever device (A1) is operated by an operator toward the boom lifting side, learning processing is initiated, and while the electric operating lever device (A1) is operated, the boom (8) moves toward the lifting side. In addition, in normal cases, when the electric operating lever device (A1) is operated, the boom cylinder (5) is driven by controlling the flow rate of the hydraulic fluid discharged from the three main pumps (201, 202, 203) by the three flow rate control valves (D1, D2, D3). However, since this embodiment is a learning focused on the flow rate control valve (D3), in the learning processing, when the electric operating lever device (A1) is operated, a command is issued only to the electronic valve (56a), and the boom cylinder (5) is driven by controlling the flow rate of the hydraulic fluid discharged from the third main pump (203) by the flow rate control valve (D3).

[0155] The learning unit (149) measures the cylinder pressure when the boom (8) is driven in the lifting direction. The learning unit (149) stores the measured cylinder pressure and the time. Here, the stored cylinder pressure is detected by the pressure sensor (5a).

[0156] In step S204, the learning unit (149) extracts the minimum value (Pmin) (hereinafter also referred to as minimum cylinder pressure) and the maximum value (Pmax) (hereinafter also referred to as maximum cylinder pressure) of the cylinder pressure from the start of measurement to the end of measurement based on the stored time and the cylinder pressure measured using the pressure sensor (5a), and proceeds to step S205 for processing.

[0157] In this way, in the present embodiment, the cylinder pressure is measured while the boom lifting operation is performed alone, and a correction value is obtained by determining whether the measured cylinder pressure falls within the range of the pressure threshold value (Ptab) of the cylinder pressure in the boom lifting operation (minimum threshold value and maximum threshold value of the cylinder pressure in the boom lifting operation) that has been predetermined. In addition, the range of the pressure threshold value (Ptab) of the cylinder pressure in the boom lifting operation during learning is set as a target range (lower limit value and upper limit value) that satisfies the target, by aiming for a cylinder pressure determined based on a tabletop calculation or an experiment using a starter, based on the opening characteristics stored in advance and the flow rate passing through the flow control valve (D3) during the area limit control.

[0158] In the second embodiment, the work device (1A) has a boom (8) rotatably mounted on the vehicle body (1B), an arm (9) rotatably mounted on the tip of the boom (8), and a bucket (10) rotatably mounted on the tip of the arm (9). The hydraulic cylinder (5) driving the work device (1A) is a boom cylinder (5) driving the boom (8). A predetermined operation to be performed by the work device (1A) to calculate a correction value of the target operating pressure of the flow control valve (D3) is a boom lifting operation that raises the boom (8) without operating the arm (9) or the bucket (10).

[0159] According to the second embodiment configured as described above, by measuring the cylinder pressure while the boom lifting operation is in progress, the conditions for initiating the learning process are reduced, and efficiency is improved, and it becomes possible to perform the learning process even in an environment where the arm cylinder (6) cannot be fully retracted.

[0160] [Example 3]

[0161] The third embodiment of the present invention will be described focusing on the differences from the first embodiment. In the first embodiment, a learning process was described with the flow control valve (D3) corresponding to the boom lifting operation as the learning target. In contrast, this embodiment describes a learning process with the flow control valve (D4) corresponding to the arm pulling operation as the learning target.

[0162] In this embodiment, in order to suppress the deterioration of precision in area limit control caused by a deviation (individual difference) from the opening characteristic table (To) due to a manufacturing error of the flow control valve (D4) corresponding to the arm pulling operation among the flow control valves (D1 to D6), the learning unit (149) learns the relationship between the opening area of ​​the flow control valve (D4) and the operating pressure generated by the solenoid valve (57a). Based on the learning result, the learning unit (149) refers to the opening characteristic table (To) and corrects the target operating pressure (PiAM1C1) calculated based on the target spool opening, thereby suppressing the deterioration of precision in area limit control caused by a deviation in the manufacturing error.

[0163] In order to learn the relationship between the opening area of ​​the meter-out passage of the flow control valve (D4) and the operating pressure generated by the electronic valve (57a), the load pressure on the meter-out side of the hydraulic cylinder (6) is measured.

[0164] In this embodiment, the load pressure on the meter-out side of the hydraulic cylinder (6) is related to the opening area of ​​the meter-out passage of the flow control valve (D4) and the operating pressure generated by the electronic valve (57a).

[0165] Therefore, by measuring the load pressure on the meter-out side of the hydraulic cylinder (6), the pressure loss (brake pressure) caused by the throttle can be measured, and the relationship between the opening area of ​​the meter-out passage of the flow control valve (D4) and the operating pressure generated by the electronic valve (57a) can be learned. In addition, as a method for measuring the pressure loss (brake pressure) caused by the throttle, in addition to the method of directly detecting the load pressure on the meter-out side of the hydraulic cylinder (6), there is a method of multiplying the load pressure on the meter-in side of the hydraulic cylinder (6) by the hydraulic pressure area ratio of the hydraulic cylinder (6).

[0166] Referring to FIG. 17, the flow of the learning process of the flow control valve (D4) executed by the learning unit (149) will be described. FIG. 17 is a flowchart showing the learning process of the flow control valve (D4) executed by the learning unit (149). When the external input device (96) is operated by an operator and a command to execute the learning process is input from the external input device (96), the learning unit (149) starts the learning process (step S301).

[0167] In step S301, the learning unit (149) reads the learning start posture data and the learning start target surface data connected to the learning of the flow control valve (D4) from the non-volatile memory (42).

[0168] In this embodiment, as shown in FIG. 10, the starting position and target plane for horizontal pulling are set. The arm angle (β) of the learning starting position data is set to a range such that the arm cylinder (6) is at its maximum retraction angle and the bucket angle (γ) is set to a range such that 0 degrees is the target angle. The learning starting target plane data is set to be parallel to the X-axis of the shovel reference coordinate system of the working device (1A), and the target range in the Z-axis direction is set such that the claw tip of the bucket (10) moves in the air. Additionally, the target angle of the boom angle (α) is the angle of the boom angle (α) when the arm angle (β) and the bucket angle (γ) satisfy the above target range and the claw tip of the bucket (10) coincides with the target plane, and the target range is set from the target angle of the boom angle (α).

[0169] In step S301, when the reading of the learning start posture data and the learning start target surface data is completed, the process proceeds to step S302. In step S302, as shown in FIG. 17, the display control unit (150) displays a learning start posture screen (53a) (see FIG. 11) on the display device (53). As shown in FIG. 11, the learning start posture screen (53a) displays a message "Please adjust the posture of the work device to the target range" urging the operator to perform an operation to set the posture of the work device (1A) to the learning start posture.

[0170] In step S302 of FIG. 17, when the learning start posture screen (53a) is displayed on the display device (53), the processing proceeds to step S303. In step S303, a determination is made as to whether the learning start conditions (learning start posture, learning start target screen, MC execution mode setting) are satisfied.

[0171] The determination of the learning start posture is a determination of whether the posture of the work device (1A) is a learning start posture. If each of the current boom angle (α), arm angle (β), and bucket angle (γ) is within a defined target range, the learning unit (149) determines that the posture of the work device (1A) is a learning start posture, and if any of the current boom angle (α), arm angle (β), and bucket angle (γ) is outside the target range, the learning unit (149) determines that the posture of the work device (1A) is not a learning start posture.

[0172] The determination of the learning start target surface is a determination of whether the excavation target surface (St) is a learning start target surface. If the excavation target surface (St) is within the target range defined in the learning start target surface data, the learning unit (149) determines that the excavation target surface (St) is a learning start target surface, and if the excavation target surface (St) is outside the target range defined in the learning start target surface data, the learning unit (149) determines that the excavation target surface (St) is not a learning start target surface.

[0173] The determination of the MC execution mode setting is a determination of whether the MC is set to an execution mode. If the MC is set to an execution mode by a mode switching switch operated by the operator, the learning unit (149) determines that the MC is set to an execution mode, and if the MC is not set to an execution mode by a mode switching switch operated by the operator, the learning unit (149) determines that the MC is not set to an execution mode.

[0174] In step S303, if all learning start conditions (learning start posture, learning start target surface, and MC execution mode settings) are determined to be positive, the processing proceeds to step S304. The determination of the learning start conditions (learning start posture, learning start target surface, and MC execution mode settings) in step S303 is repeated at a predetermined control cycle until a positive determination is made.

[0175] In step S303, if the determination of the learning start condition is positive, the display control unit (150) displays an operation instruction screen on the display device (53). On the operation instruction screen, an operation instruction is displayed saying, "Please operate the arm operation lever to the pull side." When the operation instruction screen is displayed in step S303, the processing proceeds to step S304.

[0176] In step S304, when the electric operating lever device (A2) is operated by the operator toward the arm pulling side, learning processing is initiated, and while the electric operating lever device (A2) is being operated, area limit control is executed, and the operation of the work device (1A) is controlled so that the tip of the bucket (10) moves along the excavation target surface (St).

[0177] The learning unit (149) measures the load pressure on the meter-out side of the hydraulic cylinder (6) when area limit control is executed and the arm (9) is driven in the arm pulling direction. Additionally, below, the load pressure on the meter-out side of the hydraulic cylinder (6) is also referred to as the arm cylinder pressure. The learning unit (149) stores the measured arm cylinder pressure and the time. Here, the stored arm cylinder pressure is detected by the pressure sensor (6a).

[0178] In step S304, the learning unit (149) extracts the minimum value (Pamin) (hereinafter also referred to as minimum arm cylinder pressure) and the maximum value (Pamax) (hereinafter also referred to as maximum arm cylinder pressure) of the arm cylinder pressure from the start of measurement to the end of measurement based on the stored time and the arm cylinder pressure measured using the pressure sensor (6a), and proceeds to step S305 for processing.

[0179] In step S305, the learning unit (149) determines whether the minimum arm cylinder pressure (Pamin) calculated in step S304 is greater than or equal to a predetermined minimum threshold value (Pm3) of the arm cylinder pressure. Additionally, the minimum threshold value (Pm3) of the arm cylinder pressure is the lower limit value when a target range (lower limit and upper limit value) satisfying the target value is set, wherein the cylinder pressure determined based on a tabletop calculation or an experiment using a starter, based on the flow rate passing through the flow control valve (D4) during area limit control and the opening characteristics stored in advance, is set as the target value.

[0180] In step S305, if it is determined that the minimum arm cylinder pressure (Pamin) is less than the minimum threshold value (Pm3) of the arm cylinder pressure, the learning unit (149) proceeds to step S307.

[0181] In step S307, the learning unit (149) obtains an arm correction value (Pica) that lowers the operating pressure by subtracting the correction value (Pica) (hereinafter also referred to as the arm correction value) of the target operating pressure of the hydraulic cylinder (6). For example, if the initial value of the correction value (Pica) is set to 1.00, in order to lower the operating pressure, 0.01 is added to the initial value to make the correction value (Pica) 1.01.

[0182] The learning unit (149) outputs the acquired arm correction value (Pica) to the correction target pressure calculation unit and returns the processing to step S302. That is, when measuring the next arm cylinder pressure, the target operating pressure (PiAM1C1) is corrected in the correction target pressure calculation unit (146), and the correction target operating pressure (PiAM1C2) is output to the valve command calculation unit (147). In addition, the correction method in the correction target pressure calculation unit (146) will be described later.

[0183] In step S305, if it is determined that the minimum arm cylinder pressure (Pamin) is greater than the minimum threshold value (Pm3) of the arm cylinder pressure, the learning unit (149) proceeds to step S306.

[0184] In step S306, the learning unit (149) determines whether the maximum arm cylinder pressure (Pamax) calculated in step S304 is less than or equal to a predetermined maximum threshold value (Pm4) of the arm cylinder pressure. Additionally, the maximum threshold value (Pm4) of the arm cylinder pressure is the upper limit value when a target range (lower limit and upper limit value) satisfying the target value is set, wherein the cylinder pressure determined based on a tabletop calculation or an experiment using a starter, based on the flow rate passing through the flow control valve (D4) during area limit control and the opening characteristics stored in advance, is set as the target value.

[0185] In step S306, if it is determined that the maximum arm cylinder pressure (Pamax) is greater than the maximum threshold value (Pm4) of the cylinder pressure, the learning unit (149) proceeds to step S308.

[0186] In step S308, the learning unit (149) obtains an arm correction value (Pica) that increases the operating pressure by adding a correction value (Pica) of the operating pressure. For example, when the initial value of the correction value (Pic) is set to 1.00, in order to increase the operating pressure, 0.01 is added to the initial value to make the correction value (Pic) 1.01.

[0187] The learning unit (149) outputs the acquired arm correction value (Pica) to the correction target pressure calculation unit and returns the processing to step S302. That is, when measuring the next cylinder pressure, the target operating pressure (PiAM1C1) is corrected in the correction target pressure calculation unit (146), and the correction target operating pressure (PiAM1C2) is output to the valve command calculation unit (147). In addition, the correction method in the correction target pressure calculation unit (146) will be described later.

[0188] In step S306, if it is determined that the maximum arm cylinder pressure (Pamax) is less than the maximum threshold value (Pm4) of the arm cylinder pressure, the learning unit (149) proceeds to step S309. In step S309, the learning unit (149) stores the arm correction value (Pica) of the operating pressure and terminates the processing shown in the flowchart of FIG. 9. Additionally, the display control unit (150) displays on the display device (53) that the learning processing has been terminated.

[0189] In this way, the learning unit (149) measures the arm cylinder pressure while the area limit control is being executed during the learning process and obtains an arm correction value (Pica) when the pressure threshold value (Ptaa) of the arm cylinder pressure (minimum threshold value (Pm3) of the arm cylinder pressure, maximum threshold value (Pm4) of the arm cylinder pressure) is entered into the range. The obtained arm correction value (Pica) is used in the correction process.

[0190] In addition, in this embodiment, as shown in FIG. 12, the measured arm cylinder pressure becomes smaller than the minimum threshold value (Pm3) of the arm cylinder pressure immediately after the area limit control is executed and the arm pulling operation is terminated, when the electric operating lever device (A2) is operated to the arm pulling side by the operator. When the measured arm cylinder pressure is smaller than the minimum threshold value (Pm3) of the arm cylinder pressure, the flow proceeding from step S305 to step S307 in FIG. 17 is repeated.

[0191] In this embodiment, a threshold value (Vtaa) is set for the secondary target speed calculated by the target speed calculation unit (144), and the cylinder pressure is measured when the secondary target speed of the hydraulic cylinder (6) is greater than or equal to the threshold value (Vtaa). That is, by measuring the arm cylinder pressure excluding the arm cylinder pressure immediately after the area limit control is executed and near the end of the arm pulling operation, the repetition of the flow proceeding from incorrect step S305 to step S307 is prevented. Furthermore, the condition for initiating the measurement of the arm cylinder pressure does not have to be a threshold value for the secondary target speed, and it is sufficient if the measurement can be performed excluding the arm cylinder pressure immediately after the area limit control is executed and near the end of the boom lifting operation.

[0192] Correction processing is described with reference to FIG. 18. FIG. 18 illustrates correction processing performed by a correction target pressure calculation unit (146). Here, the target operating pressure (PiAM1C1) is calculated by the target pressure calculation unit (145), and the arm correction value (Pica) is obtained from the learning unit (149). The correction target pressure calculation unit (146) receives the target operating pressure (PiAM1C1) output from the target pressure calculation unit (145) and reads the arm correction value (Pica) obtained from the learning unit (149). In this embodiment, since learning processing regarding the flow control valve (D4) is performed, in the correction processing, the target pressure calculation unit (145) outputs the target operating pressure (PiAM1C1) corresponding to the flow control valve (D4) to the correction target pressure calculation unit (146). In addition, the target operating pressure output from the target pressure calculation unit (145) to the valve command calculation unit (147) is the target operating pressure excluding the target operating pressure (PiAM1C1) (Pi1(PiBM12U1, PiBM3U1, PiBM12D1, PiBM3D1, PiAM2C1, PiAM1D1, PiAM2D1, PiBKC1, PiBKD1)).

[0193] The corrected target pressure calculation unit (146) calculates the corrected target operating pressure (Pi2) by multiplying the target operating pressure (PiAM1C1) and the arm correction value (Pica), and outputs it to the valve command calculation unit (147).

[0194] According to the third embodiment described above, it has the following functional effects.

[0195] (1) The target pressure calculation unit (145) calculates the target value (target operating pressure) (Pi1) of the operating pressure generated by the electronic valves (55a to 59b) based on the opening characteristic table (To), the target spool opening (Aout in this embodiment), and the operating pressure (Pi0). The target pressure calculation unit (145) related to this embodiment outputs PiAM1C1 among the target operating pressures (Pi1) to the corrected target pressure calculation unit (146).

[0196] The corrected target pressure calculation unit (146) calculates the corrected target operating pressure (PiAM1C2) based on the target operating pressure (PiAM1C1) and the arm correction value (Pica) obtained through the learning processing of the learning unit (149). The valve command calculation unit (147) controls the electronic valves (55a to 59b) based on the corrected target operating pressure (PiAM1C2) and the target operating pressure (Pi1) excluding the target operating pressure (PiAM1C1).

[0197] The learning unit (149) measures the arm cylinder pressure of the flow control valve (D4) while the area limit control is being executed, and performs a learning process to obtain an arm correction value (Pica) when the measured arm cylinder pressure (minimum arm cylinder pressure (Pamin), maximum arm cylinder pressure (Pamax)) falls within the range of a predetermined pressure threshold value (Ptaa) of the arm cylinder pressure (minimum threshold value of cylinder pressure (Pm3), maximum threshold value of cylinder pressure (Pm4)).

[0198] In the learning process, by measuring the cylinder pressure (minimum arm cylinder pressure (Pamin), maximum arm cylinder pressure (Pamax)) and obtaining a correction value (Pica) of the operating pressure so that it falls within the range of a predetermined pressure threshold value (Ptaa), the pressure loss (brake pressure) caused by the throttle of the meter-out opening can be brought into the target range.

[0199] According to this configuration, the influence of manufacturing errors of the flow control valve (D4) is reduced through learning and correction, and the opening characteristics of the flow control valve that were previously used in the prototype are reproduced, thereby allowing the flow control valve to be controlled. As a result, the claw tip (control point) of the bucket (10) can be moved with high precision in area limit control, etc.

[0200] In addition, the hydraulic system may be a closed center system or, as shown in FIG. 14, an open center system. When the controller (40) related to this embodiment wants to operate the hydraulic cylinders (5-7) at a predetermined target flow rate (target speed), it calculates the target opening area using an orifice formula that considers the target flow rate (target speed) and the load pressure of the hydraulic cylinders (5-7). Therefore, even if an open center system is adopted in the hydraulic system, the hydraulic cylinders (5-7) can be operated at the target flow rate (target speed) regardless of whether the load is light or heavy.

[0201] In this way, according to the present embodiment, deviations in the operation of hydraulic cylinders caused by individual differences in working machines are suppressed regardless of the configuration of the hydraulic system, thereby providing a working machine capable of working with high precision.

[0202] (2) The learning unit (149) sets as one of the conditions for initiating learning processing at least the position of the work device (1A) being the learning start position and the excavation target surface (St) being the learning start target surface. By doing so, the learning unit (149) can appropriately obtain an arm correction value (Pica), and the correction target pressure calculation unit (146) can correct the target operating pressure (Pi1) with high precision.

[0203] In addition, if the learning process of the third embodiment is performed after the learning process of the first or second embodiment, the deterioration of precision in the area limit control due to the manufacturing error of the flow control valve (D4, D5) corresponding to the arm pulling operation in addition to the manufacturing error of the flow control valve (D3) corresponding to the boom lifting operation can be suppressed, thereby providing a work machine capable of operating with high precision. In addition, the learning process of the first or second embodiment may be performed after the learning process of the third embodiment.

[0204] In the third embodiment, a work machine (1) comprises a vehicle body (1B), a work device (1A) rotatably mounted on the vehicle body (1B), a hydraulic cylinder (6) for driving the work device (1A), an operating device (A2) for operating the work device (1A), a hydraulic pump (202), a flow control valve (D4) for controlling the flow rate of hydraulic fluid supplied from the hydraulic pump (202) to the hydraulic cylinder (6), electronic valves (57a, 57b) for generating an operating pressure of the flow control valve (D4), and a controller (40) that calculates a target speed of the hydraulic cylinder (6) based on the amount of operation of the operating device (A2) so that the operating range of the work device (1A) is limited to above and above a target surface (St), calculates a target operating pressure of the flow control valve (D4) based on the target speed, and controls the electronic valves (57a, 57b) according to the target operating pressure, wherein the meter-out pressure of the hydraulic cylinder (6) The controller (40) is equipped with pressure sensors (6a, 6b) for measurement, and calculates a correction value (Pica) of the target operating pressure to bring the measured meter-out pressure into a range from a predetermined first lower limit value (Pm3) to a predetermined first upper limit value (Pm4) while driving the hydraulic cylinder (6) to perform a predetermined operation on the work device (1A), and corrects the target operating pressure according to the correction value (Pica).

[0205] In addition, the controller (40) in the third embodiment calculates a correction value (Pica) to decrease the target operating pressure when the minimum value (Pmin) of the meter-out pressure measured while the work device (1A) is performing the predetermined operation falls below the first lower limit value (Pm3), and calculates a correction value (Pica) to increase the target operating pressure when the maximum value (Pmax) of the meter-out pressure measured while the work device (1A) is performing the predetermined operation exceeds the first upper limit value (Pm4), thereby correcting the target operating pressure by increasing or decreasing the target operating pressure according to the correction value (Pica).

[0206] According to the third embodiment configured as described above, by correcting the target operating pressure of the flow control valve (D4) so ​​that the meter-out pressure of the hydraulic cylinder (6) driving the work device (1A) falls within a predetermined range (Pm3 to Pm4), the deterioration of the speed responsiveness of the hydraulic cylinder (6) driving the work device (1A) and flapping or rotation of the hydraulic cylinder (6) can be prevented, thereby making it possible to perform work with high precision.

[0207] In addition, the pressure sensor (6b) in the third embodiment detects the meter pressure of the hydraulic cylinder (6), and the controller (40) calculates the measured value of the meter-out pressure by multiplying the meter pressure detected by the pressure sensor (6b) by the hydraulic pressure area ratio of the hydraulic cylinder (6). By doing so, it becomes possible to measure the meter-out pressure of the hydraulic cylinder (6) even if the pressure sensor (6a) for detecting the meter-out pressure of the hydraulic cylinder (6) is not provided.

[0208] In addition, the work device (1A) in the third embodiment has a boom (8) rotatably mounted on the vehicle body (1B), an arm (9) rotatably mounted on the tip of the boom (8), and a bucket (10) rotatably mounted on the tip of the arm (9), and the hydraulic cylinder (6) is an arm cylinder (6) that drives the arm (9), and the predetermined operation is a horizontal pulling operation that pulls the bucket (10) so that the claw end of the bucket (10) moves along a target plane (St) set parallel to the ground. By doing so, it becomes possible to perform the horizontal pulling operation with high precision.

[0209] [Example 4]

[0210] Regarding the fourth embodiment of the present invention, the differences from the first embodiment will be explained. The pressure on the meter-in side and the pressure on the meter-out side of the hydraulic cylinder (5) change depending on the temperature of the hydraulic fluid. For this reason, the controller (40) related to this embodiment performs learning processing only when the temperature of the hydraulic fluid is above a predetermined temperature threshold value.

[0211] FIG. 19 is a flowchart illustrating a learning process executed by a learning unit (149) related to the present embodiment. In FIG. 19, the difference from the first embodiment (shown in FIG. 9) is that step S401 is added after step S102.

[0212] In step S401, the learning unit (149) determines whether the temperature (Te) of the operating fluid detected by the temperature sensor (19) is greater than or equal to a temperature threshold value (Tte). The temperature threshold value (Tte) is stored in advance in the non-volatile memory (42). If the determination result of step S401 is NO, the processing proceeds to step S102, and if the determination result is YES, the processing proceeds to step S103. The determination processing of step S401 is repeated at a predetermined control cycle until a positive determination is made.

[0213] As such, in this embodiment, the conditions for initiating learning processing are set such that the posture of the working device (1A) is the learning start posture, the learning start target surface, the mode for executing MC, and the temperature (Te) of the working fluid is greater than or equal to the temperature threshold value (Tte). Thus, by making the condition that the temperature (Te) of the working fluid is greater than or equal to the temperature threshold value (Tte) one of the conditions for initiating learning processing (steps S104 to S109), learning processing is prevented when the temperature (Te) of the working fluid is less than the temperature threshold value (Tte). As a result, since changes in the pressure on the meter-out side due to the temperature of the working fluid can be prevented, changes in the learning results due to the temperature of the working fluid can be suppressed, thereby improving the precision of the area limit control.

[0214] In the fourth embodiment, the working machine (1) is equipped with a temperature sensor (19) that detects the temperature (Te) of the working fluid, and the controller (40) calculates a correction value (Pic) when the temperature (Te) of the working fluid detected by the temperature sensor (19) is greater than or equal to a predetermined threshold value (Tte).

[0215] According to the fourth embodiment configured as described above, since the change in pressure on the meter-out side due to the temperature of the operating fluid can be prevented, the change in the learning result due to the temperature of the operating fluid can be suppressed, thereby improving the precision of the area limit control.

[0216] [Example 5]

[0217] Regarding the fifth embodiment of the present invention, the differences from the first embodiment will be explained in detail. It was explained that the learning start target surface data stored in the learning unit (149) described in the first embodiment is parallel to the X-axis of the shovel reference coordinate system of the working device (1A), and the target range in the Z-axis direction is set so that the claw tip of the bucket (10) moves in the air. However, it may be angled with respect to the X-axis of the shovel reference coordinate system of the working device (1A). In addition, it is set to the range in which the flow control valve used as the learning target operates.

[0218] [Example 6]

[0219] Regarding the sixth embodiment of the present invention, the differences from the first embodiment will be explained. FIG. 20 is a flowchart showing a learning process executed by a learning unit (149) related to the present embodiment. In FIG. 20, the difference from the first embodiment (shown in FIG. 9) is that steps S501 to S503 are executed instead of steps S105 and S106.

[0220] Following step S104, in step S501, the learning unit (149) calculates the average value (Pav) of the cylinder pressure on the meter-out side measured in step S104 (hereinafter also referred to as average cylinder pressure) and proceeds to step S502 for processing.

[0221] In step S502, the learning unit (149) determines whether the average cylinder pressure (Pav) is greater than or equal to a lower threshold value (Pav1). If the result of the determination in step S502 is NO, the processing proceeds to step S107, and if the result of the determination is YES, the processing proceeds to step S503.

[0222] In step S503, the learning unit (149) determines whether the average cylinder pressure (Pav) is below the upper threshold value (Pav2). If the determination result is NO, the processing proceeds to step S108, and if the determination result is YES, the processing proceeds to step S109.

[0223] In addition, the lower threshold value (Pav1) and the upper threshold value (Pav2) are the lower and upper values ​​when a target range (lower and upper limits) satisfying the said target value is set by setting the cylinder pressure, which is determined based on a tabletop calculation or an experiment using a starter, based on the opening characteristics of the flow control valve (D3) stored in advance and the flow rate passing through the flow control valve (D3) during area limit control.

[0224] In this embodiment, the average cylinder pressure (Pav) is compared with the lower threshold value (Pav1) of the average value of the cylinder pressure and the upper threshold value (Pav2) of the average value of the cylinder pressure to obtain a correction value (Pic) of the operating pressure. By calculating the correction value (Pic) based on the average cylinder pressure (Pav), learning processing can be performed by taking into account the temporary decrease or increase in cylinder pressure, deviation, etc., during the measurement of the cylinder pressure, thereby preventing the flow of FIG. 20 from proceeding to an incorrect step.

[0225] In addition, the learning process described in the first embodiment (shown in FIG. 9) includes a step of determining the measured cylinder pressure by comparing it with a minimum threshold value (Pm1) of the cylinder pressure and a maximum threshold value (Pm2) of the cylinder pressure, and in this embodiment, there is a step of determining the cylinder pressure by comparing it with a lower threshold value (Pav1) of the average value of the cylinder pressure and an upper threshold value (Pav2) of the average value of the cylinder pressure. Any one of these or any combination thereof may be used, and by combining them, it is possible to prevent the flow from proceeding to an incorrect step.

[0226] In the sixth embodiment, the controller (40) calculates the average value (Pav) of the meter-out pressure of the boom cylinder (5) measured while the work device (1A) is performing a predetermined operation, and if the average value (Pav) is lower than a predetermined second lower limit value (Pav1), it calculates a correction value (Pic) to decrease the target operating pressure of the flow control valve (D3), and if the average value (Pav) is higher than a second upper limit value (Pav2), it calculates the correction value to increase the target operating pressure.

[0227] According to the 6th embodiment configured as described above, by calculating a correction value (Pic) based on the average cylinder pressure (Pav), learning processing can be performed by taking into account the temporary decrease or increase in cylinder pressure, deviation, etc., during the measurement of cylinder pressure, so that it is possible to prevent the flow of FIG. 20 from proceeding to an incorrect step.

[0228] [Example 7]

[0229] Regarding the seventh embodiment of the present invention, the differences from the first embodiment will be explained in detail. In the correction processing performed by the correction target pressure calculation unit (146) related to the first embodiment, the target operating pressure (PiBM3U1) corresponding to the flow control valve (D3) is obtained by the target pressure calculation unit (145), and the correction value (Pic) of the operating pressure obtained by the learning processing by the learning unit (149) is obtained, and the correction target operating pressure (PiBM3U2) is obtained by multiplying as shown in FIG. 13. However, as shown in FIG. 21, the correction target operating pressure (PiBM3U2) may also be calculated by adding the correction value (Pic) of the operating pressure to the target operating pressure (PiBM3U1). In addition, as shown in FIG. 21, when calculating the corrected target operating pressure (PiBM3U2) by adding, the initial value of the correction value (Pic) is set to 0.00. In S108 of FIG. 9, if the command pressure is to be increased, 0.01 is added to the initial value at each learning step, and in S107 of FIG. 9, if the operating pressure is to be decreased, 0.01 is subtracted from the initial value. Furthermore, the method of correcting the target operating pressure according to the correction value (Pic) is not limited to the method of multiplying or adding the correction value (Pic) to the target operating pressure.

[0230] [Example 8]

[0231] Regarding the eighth embodiment of the present invention, the differences from the first embodiment will be explained in detail. In the learning process described in the first embodiment, the precision increases as the deviation from the target flow rate (design value) (Qc) of the discharge flow rate of the main pumps (201, 202, 203) corresponding to the regulator pressure becomes smaller. For this reason, it is preferable to perform correction of the regulator pressure for the discharge flow rate of the main pumps (201, 202, 203) and then perform correction (learning and correction) of the target operating pressure for the target opening area of ​​the flow control valves (D1 to D6). If the discharge flow rate of the main pumps (201, 202, 203) has a deviation from the target flow rate (design value) (Qc), the measured cylinder pressure also has a deviation, and it becomes impossible to determine whether the opening area corresponding to the target pressure (pressure threshold value of the arm cylinder pressure) (Ptaa) has been obtained. For this reason, in this embodiment, the discharge flow rate of the main pumps (201, 202, 203) is set to discharge working fluid at a rate close to the design value, and then learning processing is performed on the flow control valves (D1 to D6). By doing so, it is possible to increase the precision of the learning processing.

[0232] [Example 9]

[0233] Regarding the ninth embodiment of the present invention, the differences from the above embodiment will be explained in detail. In the above embodiment, when performing learning processing, hydraulic fluid may be supplied to multiple hydraulic cylinders from a single hydraulic pump. On the other hand, in MC, it is important to drive the hydraulic cylinders according to the target speed, and excavation precision is achieved by driving one hydraulic cylinder with one hydraulic pump (preventing splitting). Therefore, it is desirable to perform learning processing under the same conditions. Thus, in this embodiment, when performing learning processing, the hydraulic cylinder to which hydraulic fluid is supplied from one hydraulic pump is limited to one.

[0234] In the ninth embodiment, the work device (1A) has a boom (8) rotatably mounted on the vehicle body (1B) and an arm (9) rotatably mounted on the tip of the boom (8); the hydraulic cylinders (5, 6) driving the work device (1A) include a boom cylinder (5) driving the boom (8) and an arm cylinder (6) driving the arm (9); the hydraulic pumps (202, 203) include a first hydraulic pump (203) of variable displacement type that preferentially supplies hydraulic fluid to the boom cylinder (5) and a second hydraulic pump (202) of variable displacement type that preferentially supplies hydraulic fluid to the arm cylinder (6); and the flow control valves (D3, D4) include a first flow control valve (D3) that controls the flow rate of hydraulic fluid supplied from the first hydraulic pump (203) to the boom cylinder (5), and the arm from the second hydraulic pump (202). It includes a second flow control valve (D4) that controls the flow rate of the operating fluid supplied to the cylinder (6), and the solenoid valves (56a to 57b) include a first solenoid valve (56a, 56b) that generates the operating pressure of the first flow control valve (D3) and a second solenoid valve (57a, 57b) that generates the operating pressure of the second flow control valve (D4). The controller (40) calculates a correction value (Pic) of the target operating pressure of the first solenoid valves (56a, 56b) using the meter-out pressure of the boom cylinder (5) measured while the work device (1A) performs an operation of driving only the first flow control valve (D3), and calculates the target operating pressure of the second solenoid valves (57a, 57b) using the meter-out pressure of the arm cylinder (6) measured while the work device (1A) performs an operation of driving only the second flow control valve (D4). Calculate the correction value (Pica).

[0235] According to the ninth embodiment configured as described above, the precision of the area limit control can be improved by calculating a correction value (Pic, Pica) for the operation of driving one hydraulic cylinder with one hydraulic pump.

[0236] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments are described in detail to facilitate understanding of the present invention, and the present invention is not necessarily limited to having all the described configurations. Furthermore, it is possible to add parts of the configurations of other embodiments to the configurations of any embodiment, delete parts of the configurations of any embodiment, or substitute parts of other embodiments. Explanation of the symbols

[0237] 1 : Hydraulic shovel (working machine) 1A: Working device 1B: Chassis 5 : Boom cylinder (hydraulic cylinder) 5a, 5b: Pressure sensors 6 : Arm cylinder (hydraulic cylinder) 6a, 6b: Pressure sensors 7: Bucket cylinder 7a, 7b: Pressure sensors 8 : Boom 9 : Aam 10 : Bucket 11 : Driving body 12: Rotating body 13 : Bucket Link 14: Vehicle body position detection device 14a: GNSS antenna 14b: GNSS antenna 15: Control valve unit 16: Driver's cab 18 : Engine 19: Temperature sensor 21: Control System 30: Boom angle sensor 31: Arm angle sensor 32: Bucket angle sensor 33: Vehicle body tilt angle sensor 39: Lock valve 40 : Controller 41: Processing unit 42 : Non-volatile memory 43 : Volatile memory 44 : Input Interface 45 : Output interface 48: Pilot pump 50: Attitude detection device 51: Target plane setting device 53 : Display device 53a : Learning Start Posture Screen 55a, 55b: Solenoid valve 56a, 56b: Solenoid valve (1st solenoid valve) 57a, 57b: Solenoid valve (second solenoid valve) 58a, 58b, 59a, 59b: Solenoid valve 91 : Boom Pin 92 : Arm pin 93 : Bucket Pin 96 : External input device 141: Manipulated variable calculation unit 142 : Detail calculation unit 143 : Target plane operation unit 144 : Target speed calculation unit 145 : Target pressure calculation unit 146 : Correction target pressure calculation unit 147 : Valve command calculation unit 148: Electronic valve control unit 149 : Study Department 150 : Display control unit 170 : Discharge piping 201: 1st Main Pump 201a : Regulator 201b: Pressure sensor 202: 2nd Main Pump (2nd Hydraulic Pump) 202a : Regulator 202b : Pressure sensor 203: 3rd Main Pump (1st Hydraulic Pump) 203a : Regulator 203b : Pressure sensor A1~A3: Electric operating lever device B1, B2: Control levers C1~C12: Pilot Line D1, D2: Flow control valves D3: Flow control valve (1st flow control valve) D4: Flow control valve (2nd flow control valve) D5, D6: Flow control valves E1~E12: Hydraulic chambers St: Target excavation surface To : Opening characteristics table

Claims

Claim 1 A work machine comprising a vehicle body, a work device rotatably mounted on the vehicle body, a hydraulic cylinder for driving the work device, an operating device for operating the work device, a hydraulic pump, a flow control valve for controlling the flow rate of hydraulic fluid supplied from the hydraulic pump to the hydraulic cylinder, an electronic valve for generating an operating pressure of the flow control valve, and a controller for calculating a target speed of the hydraulic cylinder based on the amount of operation of the operating device so as to limit the operating range of the work device to a target surface and above it, calculating a target operating pressure of the flow control valve based on the target speed, and controlling the electronic valve according to the target operating pressure, wherein the work machine comprises a pressure sensor for measuring the meter-out pressure of the hydraulic cylinder, and wherein the controller calculates a correction value of the target operating pressure to bring the meter-out pressure measured while driving the hydraulic cylinder to perform a predetermined operation of the work device into a range from a predetermined first lower limit value to a predetermined first upper limit value, and corrects the target operating pressure according to the correction value. Claim 2 A work machine according to claim 1, wherein the controller calculates a correction value to decrease the target operating pressure when the minimum value of the meter-out pressure measured while the work device is performing the predetermined operation falls below the first lower limit value, and calculates a correction value to increase the target operating pressure when the maximum value of the meter-out pressure measured while the work device is performing the predetermined operation exceeds the first upper limit value, and corrects the target operating pressure by increasing or decreasing the target operating pressure according to the correction value. Claim 3 A work machine according to claim 1, wherein the controller calculates the average value of the meter-out pressure measured while the work device is performing the predetermined operation, calculates the correction value to decrease the target operating pressure when the average value falls below a predetermined second lower limit, and calculates the correction value to increase the target operating pressure when the average value exceeds a predetermined second upper limit. Claim 4 A working machine according to claim 1, wherein the pressure sensor detects the meter pressure of the hydraulic cylinder, and the controller calculates the measured value of the meter-out pressure by multiplying the meter pressure detected by the pressure sensor by the hydraulic pressure area ratio of the hydraulic cylinder. Claim 5 A working machine according to claim 1, comprising a temperature sensor for detecting the temperature of the operating fluid, and wherein the controller calculates the correction value when the temperature of the operating fluid detected by the temperature sensor is greater than or equal to a predetermined threshold value. Claim 6 A work machine according to claim 1, wherein the work device comprises a boom rotatably mounted on the vehicle body, an arm rotatably mounted on the tip of the boom, and a bucket rotatably mounted on the tip of the arm, wherein the hydraulic cylinder is a boom cylinder that drives the boom or an arm cylinder that drives the arm, and wherein the predetermined operation is a horizontal pulling operation that pulls the bucket so that the claw end of the bucket moves along the target plane set parallel to the ground. Claim 7 A work machine according to claim 1, wherein the work device comprises a boom rotatably mounted on the vehicle body, an arm rotatably mounted on the tip of the boom, and a bucket rotatably mounted on the tip of the arm, wherein the hydraulic cylinder is a boom cylinder that drives the boom, and the predetermined operation is a boom lifting operation that raises the boom without operating the arm or the bucket. Claim 8 In claim 1, the working device comprises a boom rotatably mounted on the vehicle body and an arm rotatably mounted on the tip of the boom; the hydraulic cylinder comprises a boom cylinder that drives the boom and an arm cylinder that drives the arm; the hydraulic pump comprises a first hydraulic pump of a variable displacement type that preferentially supplies hydraulic fluid to the boom cylinder and a second hydraulic pump of a variable displacement type that preferentially supplies hydraulic fluid to the arm cylinder; the flow control valve comprises a first flow control valve that controls the flow rate of hydraulic fluid supplied from the first hydraulic pump to the boom cylinder and a second flow control valve that controls the flow rate of hydraulic fluid supplied from the second hydraulic pump to the arm cylinder; the solenoid valve comprises a first solenoid valve that generates an operating pressure of the first flow control valve and a second solenoid valve that generates an operating pressure of the second flow control valve; and the controller comprises such that the predetermined operation drives only the first flow control valve A working machine characterized by calculating a correction value of the target operating pressure of the first solenoid valve in the case of operation, and calculating a correction value of the target operating pressure of the second solenoid valve in the case where the predetermined operation is an operation that drives only the second flow control valve.

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