Work machine

Abstract

The purpose of the present invention is to provide a work machine capable of performing work with high precision by preventing deterioration in speed responsiveness of a hydraulic cylinder for driving a work device, and fluctuation and runaway of the hydraulic cylinder. Therefore, the controller calculates a correction value for a target operating pressure of the flow rate control valve for correcting the target operating pressure on the basis of the correction value, the correction value being used for correcting the target operating pressure of the flow rate control valve when the outlet throttle pressure of the hydraulic cylinder measured during a period in which the hydraulic cylinder is driven to cause the work device to perform a predetermined operation. And converges within a range from a prescribed first lower limit value to a prescribed first upper limit value.

Description

Technical Field

[0001] The present invention relates to a working machine capable of performing machine control. Background Art

[0002] In recent years, expectations for semi-automatic driving, automatic driving, remote control, etc. of hydraulic excavators and other working machines have been increasing, and the electronic control of working machines has been developing. As a method for electronic control of working machines, there is a method of using a solenoid valve to control a hydraulic actuator. For example, there is a method known to use a pilot pressure (operating pressure) generated by a solenoid valve to operate a control valve for controlling a hydraulic actuator such as a hydraulic cylinder or a hydraulic motor.

[0003] In semi-automatic driving or automatic driving, in area-limited control for moving the claw tip of a bucket along a predetermined target surface, it is particularly important to control a plurality of hydraulic actuators at a target speed of each actuator with high accuracy regardless of load conditions or speeds. Here, the following technology is known: in electronic control of a working machine, the data used for control is corrected in consideration of individual differences of the working machine to improve excavation accuracy (see Patent Document 1).

[0004] Patent document 1 discloses an invention for the purpose of improving the excavation accuracy in semi-automatic driving. The working device described in Patent document 1 has a controller that stores the following data: data that specifies the relationship between the operating pressure and the movement speed of the hydraulic cylinder. The controller causes the current value of the current output to the solenoid valve (electromagnetic proportional control valve) that generates the operating pressure to increase in stages. The controller corrects the relationship between the operating pressure and the movement speed of the hydraulic cylinder in the above data based on the current value at which the hydraulic cylinder starts to move and the movement speed of the hydraulic cylinder when the current of a predetermined current value is output to the solenoid valve. In addition, the movement speed of the hydraulic cylinder takes the working oil flow to the inlet side of the hydraulic cylinder, i.e., the inlet throttling flow, and the opening of the control valve for controlling the inlet throttling flow, i.e., the inlet throttling opening, as factors.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: International Publication No. 2015 / 137525 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, in the data correction that specifies the relationship between the operating pressure and the movement speed of the hydraulic cylinder based on the movement speed of the hydraulic cylinder taking the inlet throttling opening and the inlet throttling flow rate as factors in Patent Document 1, the pressure loss (brake pressure) caused by the throttling of the outlet throttling opening is not taken into account, and even when the hydraulic cylinder is driven at the desired movement speed, the excavation accuracy may be deteriorated due to the deviation of the outlet throttling opening.

[0010] Specifically, if the pressure loss caused by throttling of the meter-out opening is too large, the hydraulic cylinder is driven with the brake being too sensitive, thereby causing deterioration in fuel consumption and speed responsiveness of the hydraulic cylinder. On the other hand, if the pressure loss caused by throttling of the meter-out opening is too small, the hydraulic cylinder is driven with the brake being insensitive, thereby losing the stability of the hydraulic cylinder's operation, causing fluctuations and loss of control of the hydraulic cylinder.

[0011] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a working machine capable of performing work with high precision by preventing deterioration of the speed responsiveness of a hydraulic cylinder driving a working device and hunting and runaway of the hydraulic cylinder.

[0012] Means for solving problems

[0013] In order to achieve the above-mentioned object, the working machine of the present invention comprises: a body; a working device rotatably mounted on the body; a hydraulic cylinder that drives the working device; an operating device for operating the working device; a hydraulic pump; a flow control valve that controls the flow rate of working oil supplied from the hydraulic pump to the hydraulic cylinder; an electromagnetic valve that generates an operating pressure of the flow control valve; and a controller that calculates a target speed of the hydraulic cylinder based on an operation amount of the operating device so that the operating range of the working device is limited 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 electromagnetic valve based on the target operating pressure, the working machine comprising: a pressure sensor that measures a meter-out pressure of the hydraulic cylinder, the controller calculates a correction value of the target operating pressure, and corrects the target operating pressure based on the correction value, wherein the correction value is used to converge the meter-out pressure measured during the period when the hydraulic cylinder is driven to cause the working device to perform a prescribed action within a range from a prescribed first lower limit value to a prescribed first upper limit value.

[0014] According to the present invention thus constructed, by correcting the target operating pressure of the flow control valve in such a manner that the outlet throttling pressure of the hydraulic cylinder driving the working device converges within a prescribed range, it is possible to prevent deterioration in the speed responsiveness of the hydraulic cylinder driving the working device, as well as fluctuation and loss of control of the hydraulic cylinder, thereby enabling operations to be performed with high precision.

[0015] Effects of the Invention

[0016] According to the present invention, it is possible to perform work with high accuracy by preventing deterioration in the speed responsiveness of a hydraulic cylinder driving a working device and preventing hunting and runaway of the hydraulic cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of a hydraulic excavator according to a first embodiment of the present invention.

[0018] Figure 2 It is a structural diagram of a hydraulic system mounted on a hydraulic excavator according to a first embodiment of the present invention.

[0019] Figure 3 It is a diagram showing a reference coordinate system of the hydraulic excavator according to the first embodiment of the present invention.

[0020] Figure 4 This is a hardware configuration diagram of a control system mounted on a hydraulic excavator according to a first embodiment of the present invention.

[0021] Figure 5 It is a diagram showing an example of a display screen of the display device according to the first embodiment of the present invention.

[0022] Figure 6 is a functional block diagram of a controller according to a first embodiment of the present invention.

[0023] Figure 7 1 is a diagram showing an example of the trajectory of the tip of the bucket when following the corrected target speed vector MC.

[0024] Figure 8 This is an opening line diagram of the meter-out passage of a flow control valve.

[0025] Fig. 9 1 is a flowchart showing a learning process executed by the learning unit according to the first embodiment of the present invention.

[0026] Fig.10 It is a diagram showing a learning start posture and a learning start target surface according to the first embodiment of the present invention.

[0027] Fig.11 1 is a diagram showing an example of a learning start posture screen according to the first embodiment of the present invention.

[0028] Fig.12 1 is a diagram showing time-series changes in cylinder pressure stored in the learning process of the first embodiment of the present invention.

[0029] Fig.13 It is a diagram showing the correction process according to the first embodiment of the present invention.

[0030] Fig.14This is a structural diagram of the hydraulic system when a center open system is adopted.

[0031] Fig.15 : is a flowchart showing the learning process executed by the learning unit according to the second embodiment of the present invention.

[0032] Fig.16 It is a diagram showing a learning start posture according to the second embodiment of the present invention.

[0033] Fig.17 : is a flowchart showing the learning process executed by the learning unit according to the third embodiment of the present invention.

[0034] Fig.18 It is a diagram showing the correction process according to the third embodiment of the present invention.

[0035] Fig.19 : is a flowchart showing the learning process executed by the learning unit according to the fourth embodiment of the present invention.

[0036] Fig. 20 : is a flowchart showing the learning process executed by the learning unit according to the sixth embodiment of the present invention.

[0037] Fig.21 It is a diagram showing the correction processing according to the seventh embodiment of the present invention. DETAILED DESCRIPTION

[0038] Hereinafter, an embodiment of the working machine of the present invention will be described with reference to the accompanying drawings, taking a hydraulic excavator as an example. In addition, in each figure, the same reference numerals are attached to the same elements, and repeated descriptions are appropriately omitted.

[0039] Example 1

[0040] Figure 1 This is a side view of a hydraulic excavator according to a first embodiment of the present invention. In addition, in this embodiment, a hydraulic excavator having a bucket as an attachment (working tool) mounted on the front end of a working device is described as an example, but the present invention can also be applied to a hydraulic excavator having attachments other than a bucket.

[0041] like Figure 1 As shown, the hydraulic excavator 1 is configured to include: a vehicle body 1B, and a multi-jointed working device (front working device) 1A mounted on the vehicle body 1B. The vehicle body 1B has: a traveling body 11 that is driven by left and right traveling motors (hydraulic motors), and a revolving body 12 mounted on the traveling body 11. The revolving body 12 is rotated relative to the traveling body 11 by the revolving motor (hydraulic motor). The revolving center axis of the revolving body 12 is vertical when the hydraulic excavator 1 is parked on a horizontal ground. A cab 16 is provided on the revolving body 12.

[0042] The working device 1A is a structure formed by connecting a plurality of driving object parts (a boom 8, an arm 9, and a bucket 10) that rotate in a vertical plane. The base end of the boom 8 is rotatably connected to the front part of the revolving 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 as a hydraulic cylinder, the arm 9 is driven by an arm cylinder 6 as a hydraulic cylinder, and the bucket 10 is driven by a bucket cylinder 7 as a hydraulic cylinder. The hydraulic cylinders 5, 6, and 7 have: a bottomed cylindrical cylinder, one end of which is closed; a cover that blocks the opening of the other end of the cylinder; a cylinder rod that passes through the cover and is inserted into the cylinder; and a piston that is provided at the front end of the cylinder rod and divides the cylinder into a rod chamber and a bottom chamber.

[0043] A boom angle sensor 30 is mounted on the boom pin 91, a bucket 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 tilt angle sensor 33 is mounted on the revolving body 12. The angle sensors 30, 31, and 32 detect the rotation angles α, β, and γ ( Figure 3 ), and outputs 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 ( Figure 3 ) and outputs a signal indicating the detection result to the controller 40 (described later).

[0044] A pair of GNSS (Global Navigation Satellite System) antennas (hereinafter referred to as GNSS antennas) 14a and 14b are provided on the rotating body 12. The controller 40 calculates the position and orientation of the rotating body 12 in the global coordinate system based on satellite signals (GNSS radio waves) received by the GNSS antennas 14a and 14b from a plurality of positioning satellites.

[0045] Figure 2 1 is a structural diagram of a hydraulic system mounted on a hydraulic excavator 1. Figure 2 In FIG. 1 , hydraulic circuits related to the boom cylinder 5 , the arm cylinder 6 , and the bucket cylinder 7 are shown, and hydraulic circuits related to the travel motor and the swing motor are omitted.

[0046] Electric operating lever devices A1 to A3 are provided in the cab 16. The electric operating lever devices A1 and A3 share an operating lever B1 disposed on the left and right sides 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 solenoid valves 55a, 55b, 56a, and 56b. As a result, 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 solenoid valves 59a and 59b. As a result, the bucket cylinder 7 (bucket 10) is driven. The electric operating lever device A2 has: an operating lever B2 disposed on the other left and right side of the driver's seat. When the electric operating lever device A2 is operated by the operating lever B2, the controller 40 operates the solenoid valves 57a, 57b, 58a, and 58b. As a result, the boom cylinder 6 (boom 9) is driven.

[0047] A pressure sensor 5a is installed at the input / output port on the rod side of the boom cylinder 5, and a pressure sensor 5b is installed at the input / output port on the bottom side of the boom cylinder 5. A pressure sensor 6a is installed at the input / output port on the rod side of the arm cylinder 6, and a pressure sensor 6b is installed at the input / output port on the bottom side of the arm cylinder 6. A pressure sensor 7a is installed at the input / output port on the rod side of the bucket cylinder 7, and a pressure sensor 7b is installed at the input / output port on the bottom side of the bucket cylinder 7.

[0048] The rotary body 12 is equipped with an engine 18 as a prime mover, 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 to discharge the hydraulic oil sucked from the oil tank. A pressure sensor 201b is installed at the discharge port of the first main pump 201, a pressure sensor 202b is installed at the discharge port of the second main pump 202, and a pressure sensor 203b is installed at the discharge port of the third main pump 203.

[0049] 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, and 203 are variable capacity hydraulic pumps whose discharge capacity (displacement) per rotation is controlled by the regulators 201a, 202a, and 203a. The main pumps 201, 202, and 203 in this embodiment are inclined plate type hydraulic pumps whose discharge capacity is controlled by the tilting angle of the inclined plate. The main pumps 201, 202, and 203 discharge pressure oil that drives multiple hydraulic actuators (boom cylinder 5, arm cylinder 6, bucket cylinder 7, etc.). The pilot pump 48 is a fixed capacity hydraulic pump whose discharge capacity per rotation is constant.

[0050] Regulators 201a, 202a, 203a are driven by hydraulic signals corresponding to target values ​​of regulator pressure (hereinafter also referred to as target regulator pressure) PPc201, PPc202, PPc203, and control the discharge capacity of main pumps 201, 202, 203, wherein the target value of the regulator pressure is calculated by the controller 40 based on the operation amount of the electric operating lever devices A1~A3.

[0051] Specifically, the regulators 201a, 202a, and 203a each have a regulator solenoid valve (not shown). The controller 40 outputs an electrical signal (excitation current) corresponding to the target regulator pressure to the regulator solenoid valve. As a result, the regulator solenoid valve is driven, and the regulator pressure for operating the inclined plate is generated through the regulator solenoid valve. The regulator solenoid valve is an electromagnetic proportional pressure reducing valve that generates a regulator pressure (pilot secondary pressure) corresponding to the instruction from the controller 40 by reducing the discharge pressure (pilot primary pressure) of the pilot pump 48.

[0052] The tilting angle of the swash plate (i.e., discharge capacity) changes due to the regulator pressure generated by the regulator solenoid valve, thereby changing the discharge flow rate of the main pumps 201, 202, 203. Therefore, the discharge flow rate of the main pumps 201, 202, 203 changes according to the target regulator pressure calculated by the controller 40.

[0053] The hydraulic system has a plurality of solenoid valves 55a to 59b. The plurality of solenoid valves 55a to 59b generate operating pressures for operating flow control valves D1 to D6 described later according to instructions (electrical signals) from the controller 40. The plurality of solenoid valves 55a to 59b are electromagnetic proportional pressure reducing valves that reduce the discharge pressure (pilot primary pressure) of the pilot pump 48 to generate operating pressures (pilot secondary pressures) corresponding to the operating directions and operating amounts of the electric operating lever devices A1 to A3.

[0054] The 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 a plurality of branches and connected to the electromagnetic valves 55a to 59b. The lock valve 39 of this embodiment is an electromagnetic switching valve, and its solenoid is electrically connected to a position sensor of a door lock rod (not shown) disposed in the cab 16 of the revolving body 12. The position of the door lock rod is detected by the position sensor, and a signal corresponding to the position of the door lock rod is input from the position sensor to the lock valve 39. If the position of the door lock rod is in the lock position, the lock valve 39 is closed, the discharge pipe 170 is blocked, and the supply of the pilot pressure from the pilot pump 48 to the electromagnetic valves 55a to 59b is blocked. If the position of the door lock rod is in the lock release position, the lock valve 39 is opened, the discharge pipe 170 is opened, and the pilot pressure is supplied from the pilot pump 48 to the electromagnetic valves 55a to 59b. In the state where the discharge pipe 170 is blocked, the operation of the electric operating lever devices A1 to A3 is invalidated, and the action such as digging is prohibited.

[0055] The controller 40 generates an electric signal (excitation current) for driving the electromagnetic valves 55a to 59b according to the operation amount and operation direction of the operating levers B1 to B2 of the electric operating lever devices A1 to A3, and outputs it to the electromagnetic valves 55a to 59b corresponding to the operation direction of the operating levers B1 and B2. The hydraulic system includes a control valve unit 15 that controls the flow of the working oil ejected 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.

[0056] The flow control valve D1 (first flow control valve) controls the flow rate of the working oil 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 solenoid valves 55a and 55b driven according to the command of the controller 40 is input to the pressure receiving chambers E1 and E2 of the flow control valve D1 through the pilot lines C1 and C2. The valve core of the flow control valve D1 is driven according to the operating pressure input to the pressure receiving chambers E1 and E2. By driving the valve core of the flow control valve D1, the supply direction and flow rate of the pressure oil from the first main pump 201 to the boom cylinder 5 are controlled, and the boom cylinder 5 is driven.

[0057] The flow control valve D2 (second flow control valve) controls the flow rate of the hydraulic oil 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 solenoid valves 55a and 55b driven according to the command of the controller 40 is input to the pressure receiving chambers E3 and E4 of the flow control valve D2 through the pilot lines C3 and C4. The valve core of the flow control valve D2 is driven according to the operating pressure input to the pressure receiving chambers E3 and E4. By driving the valve core of the flow control valve D2, the supply direction and flow rate of the pressure oil from the second main pump 202 to the boom cylinder 5 are controlled, and the boom cylinder 5 is driven.

[0058] The flow control valve D3 (third flow control valve) controls the flow rate of the working oil 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 solenoid valves 56a and 56b driven according to the command of the controller 40 is input to the pressure receiving chambers E5 and E6 of the flow control valve D3 through the pilot lines C5 and C6. The valve core of the flow control valve D3 is driven according to the operating pressure input to the pressure receiving chambers E5 and E6. By driving the valve core of the flow control valve D3, the supply direction and flow rate of the pressure oil from the third main pump 203 to the boom cylinder 5 are controlled, and the boom cylinder 5 is driven.

[0059] In this way, the boom cylinder 5 is driven by controlling the flow rate of the hydraulic oil ejected from the three main pumps 201, 202, 203 by the three flow control valves D1, D2, D3. In addition, when the controller 40 issues a command to only the electromagnetic valves 56a and 56b among the electromagnetic valves 55a, 55b, 56a, and 56b, the boom cylinder 5 is driven only by the hydraulic oil ejected from the third main pump 203.

[0060] The flow control valve D4 (fourth flow control valve) controls the flow rate of the working oil supplied from the second main pump 202 to the boom cylinder 6 according to the operation of the electric operating lever device A2. The operating pressure generated by the solenoid valves 57a and 57b driven according to the command of the controller 40 is input to the pressure chambers E7 and E8 of the flow control valve D4 through the pilot lines C7 and C8. The valve core of the flow control valve D4 is driven according to the operating pressure input to the pressure chambers E7 and E8. By driving the valve core of the flow control valve D4, the supply direction and flow rate of the pressure oil from the second main pump 202 to the boom cylinder 6 are controlled, and the boom cylinder 6 is driven.

[0061] The flow control valve D5 (fifth flow control valve) controls the flow rate of the working oil supplied from the first main pump 201 to the boom cylinder 6 according to the operation of the electric operating lever device A2. The operating pressure generated by the solenoid valves 58a and 58b driven according to the command of the controller 40 is input to the pressure chambers E9 and E10 of the flow control valve D5 through the pilot lines C9 and C10. The valve core of the flow control valve D5 is driven according to the operating pressure input to the pressure chambers E9 and E10. By driving the valve core of the flow control valve D5, the supply direction and flow rate of the pressure oil from the first main pump 201 to the boom cylinder 6 are controlled, and the boom cylinder 6 is driven.

[0062] In this way, the boom cylinder 6 is driven by controlling the flow rate of the working oil supplied from the two main pumps 201 and 202 by the two flow control valves D4 and D5. In addition, when the controller 40 issues instructions only to the solenoid valves 57a and 57b among the solenoid valves 57a, 57b, 58a, and 58b, the boom cylinder 6 is driven only by the working oil ejected from the second main pump 202.

[0063] The flow control valve D6 (sixth flow control valve) controls the flow rate of the hydraulic oil 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 solenoid valves 59a and 59b driven according to the command of the controller 40 is input to the pressure receiving chambers E11 and E12 of the flow control valve D6 through the pilot lines C11 and C12. The valve core of the flow control valve D6 is driven according to the operating pressure input to the pressure receiving chambers E11 and E12. By driving the valve core of the flow control valve D6, the supply direction and flow rate of the pressure oil 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 hydraulic oil ejected from the first main pump 201 by the flow control valve D6.

[0064] Figure 3 The posture of the working device 1A can be determined based on Figure 3 It is defined by the excavator reference coordinate system shown. Figure 3 The excavator reference coordinate system is a coordinate system set with the rotating body 12 as a reference. In the excavator reference coordinate system, the origin is set at the center axis of the boom pin 91, the Z axis is set parallel to the rotation center axis of the rotating body 12 (directly above the rotating body 12), and the X axis is set in a direction orthogonal to the Z axis (in front of the rotating body 12). Hereinafter, the inclination angle of the boom 8 relative to the X axis is denoted as the boom angle α, the inclination angle of the arm 9 relative to the boom 8 is denoted as the arm angle β, and the inclination angle of the bucket 10 relative to the arm 9 is denoted as the bucket angle γ. In addition, the inclination angle of the vehicle body 1B (rotating body 12) relative to the horizontal plane (reference plane), that is, the angle formed by the horizontal plane (reference plane) and the X axis is denoted as the vehicle body inclination angle θ.

[0065] The boom angle α is detected by the boom angle sensor 30, the arm angle β is detected by the arm angle sensor 31, the bucket angle γ is detected by the bucket angle sensor 32, and the vehicle body tilt angle θ is detected by the vehicle body tilt angle sensor 33. The boom angle α is minimum when the boom 8 is raised to the upper limit (the boom cylinder 5 is in the maximum extension state), and is maximum when the boom 8 is lowered to the lower limit (the boom cylinder 5 is in the maximum contraction state). The arm angle β is minimum when the arm cylinder 6 is in the maximum contraction state, and is maximum when the arm cylinder 6 is in the maximum extension state. The bucket angle γ is maximum when the bucket cylinder 7 is in the maximum contraction state ( Figure 3 It is minimum when the bucket cylinder 7 is in the state of maximum extension and it is maximum when the bucket cylinder 7 is in the state of maximum extension.

[0066] The position of the front end of the bucket 10 in the excavator reference coordinate system (hereinafter referred to as the front end position Pb) is expressed by the following (Formula 1) and (Formula 2) by setting Xbk as the X direction position and Zbk as the Z direction position.

[0067] Xbk=L1cos(α)+L2cos(α+β)+L3cos(α+β+γ)…(Formula 1)

[0068] Zbk=L1sin(α)+L2sin(α+β)+L3sin(α+β+γ)…(Formula 2)

[0069] Here, L1 is the length from the center axis of the boom pin 91 connecting the revolving 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 front end position (e.g., the claw tip of the bucket 10) Pb of the bucket 10.

[0070] Reference Figure 4 , a control system 21 that performs machine control (Machine Control: MC) and machine guidance (Machine Guidance: MG) will be described. Figure 4 It is a hardware configuration diagram of the control system 21 mounted on the hydraulic excavator 1 .

[0071] The controller 40 has the following functions: when at least one of the electric operating lever devices A1 to A3 is operated, the MC function intervenes in the operator's operation under certain conditions to limit the movement of the working device 1A. The MC includes the following controls: "area restriction control" executed when the boom operation based on the electric operating lever device A2 or the boom operation based on the electric operating lever device A1 is performed; and "stop control" executed when the boom lowering operation based on the electric operating lever device A1 or the bucket operation based on the electric operating lever device A3 is performed.

[0072] Area restriction control is also called "ground leveling control". During the execution of area restriction control, at least one of the boom cylinder 5, the arm cylinder 6 and the bucket cylinder 7 is controlled so that the working device 1A does not dig deeper than the excavation target surface St (see Figure 3 ) area on the lower side. In the area limitation control, the movement of the working device 1A is controlled by the boom operation and the boom operation so that the front end of the bucket 10 moves along the excavation target surface St. For example, when the boom operation is performed, the controller 40 issues an instruction to raise the boom or lower the boom so that the velocity vector of the front end of the bucket 10 in the direction perpendicular to the excavation target surface St becomes zero. In addition, when the boom operation is performed, the controller 40 issues an instruction to pull back the boom or push out the boom so that the velocity vector of the front end of the bucket 10 in the direction perpendicular to the excavation target surface St becomes zero. Thus, the trajectory of the front end of the bucket 10 based on the boom movement or the boom movement as a rotational motion is corrected to a straight track along the excavation target surface St.

[0073] Stop control is control to stop the boom lowering operation or bucket movement so that the tip of the bucket 10 does not intrude into the area below the excavation target surface St. In stop control, the controller 40 decelerates the boom lowering operation or bucket movement as the tip of the bucket 10 approaches the excavation target surface St.

[0074] In addition, in this embodiment, the control point of the working device 1A in the MC is set to the claw tip of the bucket 10 of the hydraulic excavator 1, but the control point can be changed to other than the claw tip of the bucket 10 as long as it is a point at the front end of the working device 1A. For example, the control point can be set at the bottom surface of the bucket 10 or the outermost part of the bucket link 13. In addition, the point on the bucket 10 that is closest to the excavation target surface St can also be set as the control point. That is, the control point can be changed according to the situation.

[0075] The following controls exist in MC: "automatic control" in which the controller 40 controls the operation of the working device 1A when the electric operating lever devices A1 to A3 are not operated; and "semi-automatic control" in which the controller 40 controls the operation of the working device 1A only when the electric operating lever devices A1 to A3 are operated. In addition, since the control based on the controller 40 intervenes in the operator's operation, MC is also called "intervention control."

[0076] In addition, as MG, e.g. Figure 5 As shown, the control system 21 executes processing to display the positional relationship between the excavation target surface St and the working device 1A (for example, the bucket 10 ) on the display device 53 .

[0077] like Figure 4 As shown, the control system 21 includes: a controller 40, a posture 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, electric operating lever devices A1 to A3, an external input device 96, pressure sensors 5a to 7b, and a temperature sensor 19. In addition, the control system 21 includes: a display device 53 connected to the controller 40 and controlled according to a signal from the controller 40, regulators 201a, 202a, 203a, and electromagnetic valves 55a to 59b.

[0078] The posture detection device 50 includes a boom angle sensor 30, an arm angle sensor 31, a bucket angle sensor 32, and a vehicle body tilt angle sensor 33. These angle sensors 30, 31, 32, 33 obtain information related to the posture of the hydraulic excavator 1 and output signals corresponding to the information. That is, the angle sensors 30, 31, 32, 33 function as posture sensors that detect the posture of the working device 1A, that is, the postures of the plurality of drive target components (boom 8, arm 9, and bucket 10) that constitute the working device 1A. In addition, the angle sensors 30, 31, 32 can be, for example, potentiometers that obtain boom angle α, arm angle β, and bucket angle γ as information related to the posture and output signals (voltages) corresponding to the obtained angles. In addition, the vehicle body tilt angle sensor 33 can adopt an IMU (Inertial Measurement Unit), which obtains angular velocity and acceleration of three orthogonal axes as information related to the posture of the rotating body 12, calculates the vehicle body tilt angle θ based on the information, and outputs a signal indicating the vehicle body tilt angle θ to the controller 40.

[0079] The controller 40 may calculate the vehicle body inclination angle θ based on the output signal of the IMU. In addition, the angle sensors 30 to 32 may be replaced by sensors (such as IMU) that measure the inclination angle relative to a reference plane and sensors that detect the stroke of the hydraulic cylinders 5 to 7.

[0080] The target surface setting device 51 is an input device including a controller for MC, and the controller for MC can output information related to the excavation target surface, such as the position information of the excavation target surface and the inclination angle information of the excavation target surface relative to the reference surface (horizontal plane), to the controller 40 as a command signal. For example, the target surface setting device 51 is connected to an external terminal (not shown) storing three-dimensional data of the excavation target surface defined by the 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 the controller for MC. In addition, the excavation target surface can also be input manually to the controller 40 via the target surface setting device 51 by an operator.

[0081] The vehicle body position detection device 14 includes a pair of GNSS antennas 14 a and 14 b , calculates the position of the vehicle body 1B (revolving body 12 ) and the orientation of the vehicle body 1B (revolving body 12 ), and outputs the calculation results to the controller 40 .

[0082] The external input device 96 is an input device that is operated by an operator and outputs an input signal corresponding to the operation to the controller 40. The external input device 96 is, for example, an electrostatic capacitance touch sensor provided on the display screen of the display device 53. In addition, the external input device 96 may also include a plurality of switches and levers.

[0083] Figure 5 is a diagram showing an example of a display screen of the display device 53. Figure 5 As shown, the display device 53 displays various display images on the display screen according to the display control signal from the controller 40. The display device 53 is, for example, a touch panel type liquid crystal monitor, which is arranged in the cab 16. As the MG function, the controller 40 causes a display image representing the positional relationship between the excavation target surface St and the working device 1A (for example, the bucket 10) to be displayed on the display screen of the display device 53. In the illustrated example, an image representing the excavation target surface St and the bucket 10 and the distance from the excavation target surface St to the front end of the bucket 10 are displayed as the target surface distance H1. The target surface distance H1 takes positive values ​​in the upward direction and negative values ​​in the downward direction based on the excavation target surface St. In addition, Figure 5 The display image shown can be displayed on the display device 53 regardless of whether the mode for executing MC is set by the mode changeover switch (not shown) operated by the operator. The operator can operate the working machine 1A by referring to the display image.

[0084] The controller 40 is composed of a computer having a processing device 41 such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), a non-volatile memory 42 such as a ROM (Read Only Memory), a flash memory, a hard disk drive, a volatile memory 43 called a so-called RAM (Random Access Memory), an input interface 44, an output interface 45, and other peripheral circuits. These hardware cooperate to make the software work and realize multiple functions. In addition, the controller 40 can be composed of one computer or multiple computers. In addition, as the processing device 41, an ASIC (application specific integrated circuit), an FPGA (Field Programmable Gate Array), etc. can be used.

[0085] The nonvolatile memory 42 stores various data such as programs that can perform various operations and threshold values. That is, the nonvolatile memory 42 is a storage medium (storage device) that can read the program that realizes the functions of this embodiment. The volatile memory 43 is a storage medium (storage device) that temporarily stores the operation results of the processing device 41 and the signals input from the input interface 44. The processing device 41 is a device that expands the program stored in the nonvolatile memory 42 in the volatile memory 43 and performs operations, and performs prescribed operations on the data taken from the input interface 44, the nonvolatile memory 42, and the volatile memory 43 according to the program.

[0086] The input interface 44 converts the signals input from various devices (posture detection device 50, target surface setting device 51, vehicle body position detection device 14, electric operating lever devices A1 to A3, external input device 96, pressure sensors 5a to 7b, 201b, 202b, 203b, and temperature sensor 19) into data that can be calculated by the processing device 41. In addition, the output interface 45 generates an output signal corresponding to the calculation result in the processing device 41, and outputs the signal to various devices (regulators 201a, 202a, 203a, solenoid valves 55a to 59b, and display device 53).

[0087] The controller 40 controls the regulators 201a to 203a, thereby changing the discharge capacity of the main pumps 201 to 203. The controller 40 controls the solenoid valves 55a to 59b, thereby operating the valve cores of the flow control valves D1 to D6 and the hydraulic cylinders 5 to 7. The controller 40 controls the display device 53, thereby displaying a predetermined image on the display screen of the display device 53.

[0088] - Controller Functions -

[0089] Reference Figure 6 , the functions of the controller 40 are described in detail. Figure 6 1 is a functional block diagram of the controller 40. The controller 40 functions as an operation amount calculation unit 141, a posture calculation unit 142, a target surface calculation unit 143, a target speed calculation unit 144, a target pressure calculation unit 145, a correction target pressure calculation unit 146, a valve command calculation unit 147, a learning unit 149, and a display control unit 150 by executing a program stored in the nonvolatile memory 42. The target pressure calculation unit 145, the correction target pressure calculation unit 146, and the valve command calculation unit 147 function as a solenoid valve control unit 148 that controls the hydraulic cylinders 5, 6, and 7 as hydraulic actuators by controlling the solenoid valves 55a to 59b.

[0090] The operation amount calculation unit 141 calculates the target value of the operation pressure (hereinafter also referred to as the operation amount operation pressure) Pi0 (PiBM12U0, PiBM3U0, PiBM12D0, PiBM3D0, PiAM1C0, PiAM2C0, PiAM1D0, PiAM2D0, PiBKC0, PiBKD0) generated by the electromagnetic valves 55a to 59b based on the operation signals (operation amount and operation direction) of the electric operating lever devices A1, A2, and A3. When the boom raising operation is performed by the electric operating lever device A1, the operation amount calculation unit 141 calculates the target value PiBM12U0 of the operation pressure generated by the electromagnetic valve 55a and the target value PiBM3U0 of the operation pressure generated by the electromagnetic valve 56a. When the boom lowering operation is performed by the electric operating lever device A1, the operation amount calculation unit 141 calculates the target value PiBM12D0 of the operation pressure generated by the electromagnetic valve 55b and the target value PiBM3D0 of the operation pressure generated by the electromagnetic valve 56b.

[0091] The operation amount calculation unit 141 calculates the target value PiAM1C0 of the operation pressure generated by the electromagnetic valve 57a and the target value PiAM2C0 of the operation pressure generated by the electromagnetic valve 58a when the boom pull-back operation (bucket arm shoveling operation) is performed by the electric operating lever device A2. The operation amount calculation unit 141 calculates the target value PiAM1D0 of the operation pressure generated by the electromagnetic valve 57b and the target value PiAM2D0 of the operation pressure generated by the electromagnetic valve 58b when the boom push-out operation (bucket arm dumping) is performed by the electric operating lever device A2.

[0092] The operation amount calculation unit 141 calculates the target value PiBKC0 of the operation pressure generated by the electromagnetic valve 59a when the bucket is pulled back (bucket loading) by the electric operating lever device A3. The operation amount calculation unit 141 calculates the target value PiBKD0 of the operation pressure generated by the electromagnetic valve 59b when the bucket is pushed out (bucket dumping) by the electric operating lever device A3.

[0093] The posture calculation unit 142 calculates the posture of the working device 1A and the front end position Pb of the bucket 10 in the excavator reference coordinate system (local coordinate system) based on the posture information (angle information) detected by the posture detection device 50 and the size information (L1, L2, L3) of the working device 1A stored in the non-volatile memory 42. The front end position Pb (Xbk, Zbk) of the bucket 10 can be calculated by (Formula 1) and (Formula 2) as described above. In addition, when the posture of the working device 1A and the front end position of the bucket 10 in the global coordinate system are required, the posture calculation unit 142 converts the coordinates of the excavator reference coordinate system into the coordinates of the global coordinate system based on the position and orientation of the rotating body 12 in the global coordinate system detected by the vehicle body position detection device 14.

[0094] The target surface calculation unit 143 sets the excavation target surface St based on the 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 the 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 (refer to FIG. 1 ) obtained by cutting the plane (operation plane of the working device) on which the working device 1A moves to the excavation target surface. Figure 3 ) as the two-dimensional excavation target surface St, wherein the excavation target surface is provided by the target surface setting device 51 in the form of three-dimensional data.

[0095] In addition, Figure 3 There is only one excavation target surface St, but there may be multiple excavation target surfaces St. When there are multiple excavation target surfaces St, the target surface calculation unit 143 sets the excavation target surface St closest to the front end of the bucket 10, located vertically below the front end of the bucket 10, or arbitrarily selected as the calculation object.

[0096] The target speed calculation unit 144 calculates the target speed of each hydraulic cylinder 5, 6, 7 in the area restriction control (ground leveling control) so that the working device 1A does not exceed the excavation target surface St and excavate a position below the excavation target surface St. The target speed calculation unit 144 calculates the target speed of each hydraulic cylinder 5, 6, 7 based on the calculation result of the posture calculation unit 142 and the calculation result of the operation amount calculation unit 141.

[0097] Reference Figure 7 , the calculation method of the target speed in the area restriction control is explained in detail. Figure 7 1 is a diagram showing an example of the trajectory of the tip of the bucket 10 when the tip of the bucket 10 is controlled according to the corrected target speed vector Vca. Figure 7 As shown in FIG. 1 , an Xt axis and a Yt axis are set. The Xt axis is an axis parallel to the excavation target surface St, and the Yt axis is an axis orthogonal to the excavation target surface St.

[0098] The target speed calculation unit 144 calculates the primary target speed of each hydraulic cylinder 5, 6, and 7 based on the operation pressure Pi0 (PiBM12U0, PiBM3U0, PiBM12D0, PiBM3D0, PiAM1C0, PiAM2C0, PiAM1D0, PiAM2D0, PiBKC0, PiBKD0) of the operation amount of the solenoid valve 55a~59b calculated by the operation amount calculation unit 141.

[0099] The target speed calculation unit 144 calculates the target speed of each hydraulic cylinder 5, 6, 7, the tip position Pb of the bucket 10 calculated by the posture calculation unit 142, and the size information (L1, L2, L3, etc.) of the working device 1A stored in the non-volatile memory 42. Figure 7 A target speed vector Vc of the front end portion of the bucket 10 is shown.

[0100] The target speed calculation unit 144 corrects the primary target speed of the necessary hydraulic cylinders among the hydraulic cylinders 5, 6, and 7 so that the component Vcy (the speed component in the Yt axis direction) of the target speed vector Vc of the front end of the bucket 10 that is perpendicular to the excavation target surface St approaches 0 (zero) as the target surface distance H1, which is the distance between the front end of the bucket 10 and the excavation target surface St, approaches 0 (zero), and calculates the secondary target speed. As a result, 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 becomes only the component Vcx (the speed component in the Xt axis direction) parallel to the excavation target surface St. Therefore, in the area limitation control, the front end (control point) of the bucket 10 is kept on or above the excavation target surface St so that the front end of the bucket 10 does not intrude into the area below the excavation target surface St. Hereinafter, the control of converting (correcting) the speed vector of the front end of the bucket 10 in this way is also referred to as the direction conversion control.

[0101] There are cases where the direction change control is performed by a combination of boom raising or boom lowering and arm shoveling, and cases where the direction change control is performed by a combination of boom raising or boom lowering and arm dumping. 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 raising direction that cancels out the downward component. On the contrary, when the target speed vector Vc includes an upward component (Vcy>0) 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 cancels out the upward component.

[0102] When the mode switching switch (not shown) is set to a mode in which the area restriction control (leveling control) is not performed, the target speed calculation unit 144 does not correct the primary target speed of each hydraulic cylinder 5 to 7 in accordance with the operation of the electric operating lever devices A1 to A3.

[0103] In this way, the target speed calculation unit 144 calculates the target speed, which is the target value of the extension speed / contraction speed of the hydraulic cylinders 5 , 6 , 7 , based on the calculation results of the operation amount calculation unit 141 and the posture calculation unit 142 .

[0104] The target pressure calculation unit 145 calculates the target valve core opening of the flow control valves D1~D6 based on the detection results of the pressure sensors 5a~7b, 201b~203b and the target speeds of the hydraulic cylinders 5, 6, 7 calculated by the target speed calculation unit, and converts the target valve core opening into a target operating pressure Pi1 (PiBM12U1, PiBM3U1, PiBM12D1, PiBM3Dl, PiAM1Cl, PiAM2C1, PiAM1Dl, PiAM2D1, PiBKC1, PiBKD1) according to the valve core opening table and outputs it.

[0105] In this embodiment, the target pressure calculation unit 145 calculates the target valve core opening on the outlet throttling side of the flow control valves D1~D6 based on the detection results of the pressure sensors 5a~7b, 201b~203b and the target speeds of each hydraulic cylinder 5, 6, and 7 calculated by the target speed calculation unit, and converts the target valve core opening on the outlet throttling side into a target operating pressure Pi1 (PiBM12U1, PiBM3U1, PiBM12D1, PiBM3Dl, PiAM1Cl, PiAM2C1, PiAM1Dl, PiAM2D1, PiBKC1, PiBKD1) and outputs it according to the target opening table on the outlet throttling side of the flow control valves D1~D6.

[0106] Reference Figure 8 , an example of the opening characteristics of the meter-out passage portions of the flow control valves D1 to D6 will be described. Figure 8 It is an opening line diagram of the outlet throttling passage of the flow control valves D1 to D6, showing the relationship between the operating pressure input to the pressure receiving chambers E1, E3, E5, E7, E9, and E11 of the flow control valves D1 to D6 and the opening area of ​​the outlet throttling passage of the flow control valves D1 to D6. Figure 8 As shown, the opening area of ​​the outlet throttle passage of the flow control valves D1 to D6 increases as the operating pressure generated by the solenoid valves 55a to 59a increases. The nonvolatile memory 42 of the controller 40 stores an opening characteristic table To that specifies the relationship between the operating pressure and the opening area of ​​the flow control valves D1 to D6.

[0107] The target pressure calculation unit 145 refers to the opening characteristic table To, and calculates the target operating pressure Pi1 (PiBM12U1, PiBM3U1, PiBM12D1, PiBM3Dl, PiAM1Cl, PiAM2C1, PiAM1Dl, PiAM2D1, PiBKC1, PiBKD1) as the target value of the operating pressure based on the outlet throttling target opening area Aout (Aout_Bm1U, Aout_Bm3U, Aout_Bm1D, Aout_Bm3D, Aout_Am1C, Aout_Am2C, Aout_Am1D, Aout_Am2D, Aout_BkC, Aout_BkD).

[0108] The target pressure calculation unit 145 calculates target flow rates Q201 , Q202 , Q203 of the main pumps 201 , 202 , 203 based on the sum of target flow rates on the meter-in sides of the hydraulic cylinders 5 to 7 allocated to the main pumps 201 , 202 , 203 .

[0109] The nonvolatile memory 42 stores in advance a regulator pressure table which defines the relationship between the target flow rates Q201, Q202, Q203 of the main pumps 201, 202, 203 and the target regulator pressures of the regulators 201a, 202a, 203a.

[0110] The target pressure calculation unit 145 refers to the regulator pressure table, and calculates the target regulator pressures PPc201 , PPc202 , PPc203 based on the calculated target flow rates Q201 , Q202 , Q203 of the main pumps 201 , 202 , 203 .

[0111] The corrected target pressure calculation unit 146 reads the correction value obtained by the learning process of the learning unit 149 described later. The corrected target pressure Pi2 is calculated and output based on the read correction value and the target operating pressure Pi1 calculated by the target pressure calculation unit 145. The correction process in the corrected target pressure calculation unit 146 will be described in detail later.

[0112] The relationship between the opening area of ​​the flow control valves D1 to D6 and the operating pressure generated by the solenoid valves 55a to 59b deviates from the opening characteristic table To due to the manufacturing error of the flow control valves D1 to D6. The manufacturing error of the flow control valves D1 to D6 includes the processing error of the valve core of the flow control valves D1 to D6, the deviation of the spring constant of the spring (centering spring) for holding the valve core in the neutral position, the processing error of the valve housing for holding the valve core in a sliding state, etc. In addition, in the direction change control in the area limit control, there are cases where the control is performed by a combination of boom raising or boom lowering and arm shoveling, and cases where the control is performed by a combination of boom raising or boom lowering and arm dumping. Due to the deviation (individual difference) from the opening characteristic table To caused by the manufacturing error of the flow control valve corresponding to the boom or arm, the accuracy of the area limit control is particularly deteriorated.

[0113] In this embodiment, in order to suppress the deterioration of the accuracy of the area restriction control caused by the deviation (individual difference) from the opening characteristic table To due to the manufacturing error of the flow control valve D3 corresponding to the boom raising action among the flow control valves D1 to D6, the learning unit 149 learns the relationship between the opening area of ​​the outlet throttle passage portion of the flow control valve D3 and the operating pressure generated by the electromagnetic 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 according to the target valve core opening, thereby suppressing the deterioration of the accuracy of the area restriction control caused by the deviation of the manufacturing error.

[0114] In order to learn 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 solenoid valve 56 a , the load pressure on the meter-out side of the hydraulic cylinder 5 is measured.

[0115] The load pressure on the outlet throttling side of the hydraulic cylinder 5 in this embodiment is related to the opening area of ​​the outlet throttling passage portion of the flow control valve D3 and the operating pressure generated by the electromagnetic valve 56a. In the flow control valve D3, the more the operating pressure generated by the electromagnetic valve 56a increases, the larger the opening area of ​​the outlet throttling passage portion of the flow control valve D3.

[0116] When the opening area of ​​the meter-out passage portion of the flow control valve D3 increases, the pressure loss (brake pressure) due to throttling of the meter-out opening decreases, and the load pressure on the meter-out side of the hydraulic cylinder 5 decreases.

[0117] On the contrary, in the flow control valve D3, the more the operating pressure generated by the electromagnetic valve 56a decreases, the smaller the opening area of ​​the outlet throttling passage portion of the flow control valve D3. If the opening area of ​​the outlet throttling passage portion of the flow control valve D3 becomes smaller, the pressure loss (brake pressure) caused by the throttling of the outlet throttling opening becomes larger, and the load pressure on the outlet throttling side of the hydraulic cylinder 5 becomes larger.

[0118] Therefore, by measuring the load pressure on the meter-out side of the hydraulic cylinder 5, the pressure loss (brake pressure) caused by throttling can be measured, and 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 electromagnetic valve 56a can be learned. In addition, as a method of measuring the pressure loss (brake pressure) caused by throttling, in addition to the method of directly detecting the load pressure on the meter-out side of the hydraulic cylinder 5, there is also a method of multiplying the load pressure on the meter-in side of the hydraulic cylinder 5 by the pressure-receiving area ratio of the hydraulic cylinder 5.

[0119] Reference Fig. 9 , the flow of the learning process of the flow control valve D3 executed by the learning unit 149 is described. Fig. 9 10 is a flowchart showing the learning process of the flow control valve D3 executed by the learning unit 149. When an operator operates the external input device 96 and an execution instruction of the learning process is input from the external input device 96, the learning unit 149 starts the learning process (step S101).

[0120] In step S101 , the learning unit 149 reads out the learning start posture data and the learning start target surface data related to the learning of the flow control valve D3 from the nonvolatile memory 42 .

[0121] Fig.10 The nonvolatile memory 42 stores: Fig.10 The learning start posture data and the learning start target surface data of the learning start posture are shown.

[0122] The learning start posture data includes a target range (lower limit value and upper limit value) of a target angle satisfying the boom angle α, a target range (lower limit value and upper limit value) of a target angle satisfying the arm angle β, and a target range (lower limit value and upper limit value) of a target angle satisfying the bucket angle γ, and the learning start target surface data includes a target range (lower limit value and upper limit value) in the Z-axis direction of the excavator reference coordinate system of the working device 1A for the excavation target surface St, and a target angle (lower limit value and upper limit value) of the X-axis of the excavation target surface St and the working device 1A.

[0123] In this embodiment, if Fig.10As shown, in order to set the starting posture and target surface of the horizontal pullback, the range is set so that the arm angle β of the learning starting posture data becomes the angle at which the arm cylinder 6 is most retracted and the bucket angle γ becomes 0 degrees as the target angle, and the learning starting target surface data is parallel to the X axis of the excavator 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. In addition, the target angle of the boom angle α becomes the angle of the boom angle α when the boom angle β and the bucket angle γ satisfy the above target range and the claw tip of the bucket 10 coincides with the target surface, and the target range is set based on the target angle of the boom angle α.

[0124] In step S101, if the reading of the learning start posture data and the learning start target surface data is completed, the process proceeds to step S102. Fig. 9 As shown, the display control unit 150 causes the display device 53 to display the learning start posture screen 53a (see Fig.11 ).like Fig.11 As shown, a message “Please adjust the posture of the working device to the target range” is displayed on the learning start posture screen 53 a to prompt the operator to perform an operation for changing the posture of the working device 1A to the learning start posture.

[0125] exist Fig. 9 In step S102, when the learning start posture screen 53a is displayed on the display device 53, the process proceeds to step S103. In step S103, it is determined whether the learning start conditions (learning start posture, learning start target surface, and MC execution mode setting) are satisfied.

[0126] The determination of the learning start posture is to determine whether the posture of the working device 1A is the learning start posture. When the current boom angle α, arm angle β, and bucket angle γ are respectively within the target range, the learning unit 149 determines that the posture of the working device 1A is the learning start posture. When any one 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 working device 1A is not the learning start posture.

[0127] The determination of the learning start target surface is a determination of whether the excavation target surface St is the learning start target surface. When the excavation target surface St is within the target range specified by the learning start target surface data, the learning unit 149 determines that the excavation target surface St is the learning start target surface, and when the excavation target surface St is outside the target range specified by the learning start target surface data, the learning unit 149 determines that the excavation target surface St is not the learning start target surface.

[0128] Determining the setting of the MC execution mode is to determine whether the mode is set to execute the MC. When the mode is set to execute the MC by the mode switching switch operated by the operator, the learning unit 149 determines that the mode is set to execute the MC, and when the mode is not set to execute the MC by the mode switching switch operated by the operator, the learning unit 149 determines that the mode is not set to execute the MC.

[0129] In step S103, when all the learning start conditions (learning start posture, learning start target surface, MC execution mode setting) are determined to be positive, the process proceeds to step S104. The determination of the learning start conditions (learning start posture, learning start target surface, MC execution mode setting) in step S103 is repeatedly performed in a predetermined control cycle until it is determined to be positive.

[0130] In step S103, when the determination process of the learning start condition is determined to be positive, the display control unit 150 causes the display device 53 to display the operation instruction screen. The operation instruction screen displays an operation instruction such as "Please operate the boom operating lever to the pull-back side". In step S103, when the operation instruction screen is displayed, the process proceeds to step S104.

[0131] In step S104, when the operator operates the electric operating lever device A2 to pull the boom back, the learning process starts. While the electric operating lever device A2 is being operated, the area restriction control is performed to control the movement of the working device 1A so that the front end of the bucket 10 moves along the excavation target surface St.

[0132] The learning unit 149 performs the area restriction control and measures the load pressure on the meter-out side of the hydraulic cylinder 5 when the boom 8 is driven in the ascending direction. In addition, the load pressure on the meter-out side of the hydraulic cylinder 5 is also hereinafter referred to as the cylinder pressure. The learning unit 149 stores the measured cylinder pressure and time. Here, the stored cylinder pressure is detected by the pressure sensor 5a.

[0133] Fig.12 The figure shows the relationship between the time stored when measuring the cylinder pressure and the cylinder pressure. In step S104, the learning unit 149 calculates the minimum value Pmin (hereinafter also referred to as the minimum cylinder pressure) and the maximum value Pmax (hereinafter also referred to as the maximum cylinder pressure) of the cylinder pressure based on the stored time and the cylinder pressure measured using the pressure sensor 5a, and the processing enters step S105.

[0134] 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 cylinder pressure threshold value Pm1. The minimum cylinder pressure threshold value Pm1 is a lower limit value when a target range (lower limit value and upper limit value) that satisfies the target value is set based on the cylinder pressure determined by theoretical calculation or experiments using a prototype, etc., based on the previously stored opening characteristics and the flow rate through the flow control valve D3 in the area restriction control.

[0135] When it is determined in step S105 that the minimum cylinder pressure Pmin is smaller than the minimum cylinder pressure threshold value Pm1, the learning unit 149 advances the process to step S107.

[0136] In step S107, the learning unit 149 subtracts the correction value Pic of the operating pressure to obtain a correction value Pic that lowers the operating pressure. For example, when the initial value of the correction value Pic is set to 1.00, 0.01 is subtracted from the initial value to set the correction value Pic to 0.99 in order to lower the operating pressure.

[0137] The learning unit 149 outputs the obtained correction value Pic to the correction target pressure calculation unit, and returns the process to step S102. That is, when measuring the next cylinder pressure, the target operating pressure PiBM3U1 is corrected by 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.

[0138] When it is determined in step S105 that the minimum cylinder pressure Pmin is greater than the minimum cylinder pressure threshold value Pm1 , the learning unit 149 advances the process to step S106 .

[0139] In step S106, the learning unit 149 determines whether the maximum cylinder pressure Pmax calculated in step S104 is less than a predetermined maximum cylinder pressure threshold value Pm2. The maximum cylinder pressure threshold value Pm2 is an upper limit value when a target range (lower limit value and upper limit value) that satisfies the target value is set based on the cylinder pressure determined by theoretical calculation or experiments using a prototype, etc., as a target value based on the previously stored opening characteristics and the flow rate through the flow control valve D3 in the area restriction control.

[0140] When it is determined in step S106 that the maximum cylinder pressure Pmax is greater than the maximum cylinder pressure threshold value Pm2, the learning unit 149 advances the process to step S108.

[0141] In step S108, the learning unit 149 adds the correction value Pic of the operating pressure to obtain a correction value Pic that increases the operating pressure. For example, when the initial value of the correction value Pic is set to 1.00, 0.01 is added to the initial value to increase the operating pressure, and the correction value Pic is set to 1.01.

[0142] The learning unit 149 outputs the obtained correction value Pic to the correction target pressure calculation unit, and returns the process to step S102. That is, when measuring the next cylinder pressure, the target operating pressure PiBM3U1 is corrected by 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.

[0143] In step S106, if it is determined that the maximum cylinder pressure Pmax is smaller than the maximum cylinder pressure threshold value Pm2, the learning unit 149 advances the process to step S109. In step S109, the learning unit 149 stores the correction value Pic of the operating pressure and ends. Fig. 9 In addition, the display control unit 150 causes the display device 53 to display that the learning process has been completed.

[0144] Thus, in the learning process, the learning unit 149 measures the cylinder pressure during the execution of the area restriction control and obtains the correction value Pic of the operating pressure when it converges to the range of the pressure threshold value Pta (the minimum threshold value Pm1 of the cylinder pressure and the maximum threshold value Pm2 of the cylinder pressure). The obtained correction value Pic is used in the correction process.

[0145] In addition, in this embodiment, if Fig.12 As shown in the figure, the cylinder pressure measured becomes smaller than the minimum threshold value Pm1 of the cylinder pressure after the operator operates the electric operating lever device A2 to pull the boom back and executes the area restriction control and near the end of the boom raising operation. When the measured cylinder pressure is smaller than the minimum threshold value Pm1 of the cylinder pressure, the cylinder pressure is repeatedly performed. Fig. 9 The process goes from step S105 to step S107.

[0146] 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 the threshold value Vta. That is, the cylinder pressure is measured by excluding the cylinder pressure after the execution of the area restriction control and near the end of the boom raising action, thereby preventing the process from mistakenly entering step S105 to step S107 repeatedly. In addition, the condition for starting the cylinder pressure measurement may not be the threshold value for the secondary target speed, as long as the cylinder pressure after the execution of the area restriction control and near the end of the boom raising action can be measured.

[0147] The valve command operation unit 147 calculates an electrical signal based on the target operating pressure Pi1 (PiBM12U1, PiBM3U1, PiBM12D1, PiBM3D1, PiAM1Cl, PiAM2C1, PiAM1D1, PiAM2D1, PiBKC1, PiBKD1) calculated by the target pressure operation unit 145 and the corrected target pressure Pi2, and outputs the calculated electrical signal to the corresponding solenoid valves 55a to 59b. In addition, the valve command operation unit 147 calculates an electrical signal based on the target regulator pressure PPc (PPc201, PPc202, PPc203) calculated by the target pressure operation unit 145, and outputs the calculated electrical signal to the regulator solenoid valves of the corresponding regulators 201a to 203a.

[0148] The solenoids of the electromagnetic valves 55a to 59b are excited according to the electrical signal (excitation current) output from the valve command operation unit 147, thereby the electromagnetic valves 55a to 59b are operated, and the operating pressure (pilot pressure) acting on the flow control valves D1 to D6 is controlled to the target operating pressure Pi1 calculated by the target pressure operation unit 145. As a result, the operating speed of the hydraulic cylinders 5 to 7 is controlled to the target speed. In addition, the solenoids of the regulator electromagnetic valves of the regulators 201a to 203a are excited according to the electrical signal (excitation current) output from the valve command operation unit 147, thereby the regulator electromagnetic valves are operated, and the regulator pressure (pilot pressure) acting on the pressure receiving parts of the regulators 201a to 203a is controlled to the target regulator pressure PPc calculated by the target pressure operation unit 145. As a result, the discharge flow rate of the main pumps 201 to 203 is controlled to the target flow rate Q201, Q202, Q203.

[0149] Reference Fig.13 The correction process will be described. Fig.13 The figure shows the correction process performed by the 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 by 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 from the learning unit 149. In this embodiment, in order to perform the learning process for the flow control valve D3, in the correction process, 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. In addition, the target operating pressure output from the target pressure calculation unit 145 to the valve instruction calculation unit 147 becomes the target operating pressure Pi1 (PiBM12U1, PiBM12D1, PiBM3D1, PiAM1Cl, PiAM2C1, PiAM1D1, PiAM2D1, PiBKC1, PiBKD1) excluding the target operating pressure PiBM3U1.

[0150] The corrected target pressure calculation unit 146 calculates the corrected target operating pressure PiBM3U2 by multiplying the target operating pressure PiBM3U1 by the correction value Pic, and outputs the calculated corrected target operating pressure to the valve command calculation unit 147 .

[0151] As described above, the controller 40 of this embodiment calculates the target valve core opening of the meter-out side of the flow control valves D1 to D6 based on the target speed of the hydraulic cylinders 5 to 7 and the detection results of the pressure sensors 5a to 7b and 201b to 203b. In addition, the controller 40 refers to the opening characteristic table To and calculates the target operating pressure based on the target valve core opening.

[0152] Then, in the learning unit 149 , a learning process is performed on the flow control valve D3 , and a correction process of the target operating pressure is performed using the correction value acquired in the learning process, thereby calculating the corrected target operating pressure.

[0153] The controller 40 controls the electromagnetic valves 55 a to 59 b so that the operating pressure generated by the electromagnetic valves 55 a to 59 b becomes the target operating pressure and the corrected target operating pressure.

[0154] In this way, by calculating the target operating pressure and correcting the target operating pressure, even if the load pressure (hydraulic load condition) of the hydraulic cylinder changes, the target opening area corresponding to the load pressure can be obtained. In addition, 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 obtained. Therefore, even if the center opening system is adopted in the hydraulic system, the hydraulic cylinders 5 to 7 can be operated with high accuracy at the calculated target flow rate (target speed), and the deterioration of the accuracy of the area restriction control caused by the deviation of the manufacturing error of the flow control valve D3 can be suppressed. As a result, operations based on MC such as area restriction control can be performed with high accuracy.

[0155] The learning process is preferably performed at the time of shipment, when the valve element of the flow control valve D3 is replaced, or when the valve element stroke changes to some extent from the characteristics at the time of shipment due to aging of the flow control valve D3. This allows MC to be performed with high accuracy over a long period of time.

[0156] According to the first embodiment described above, the following effects are achieved.

[0157] (1) The target pressure calculation unit 145 calculates the target value (target operating pressure) Pi1 of the operating pressure generated by the solenoid valves 55a to 59b based on the opening characteristic table To, the target valve core opening (Aout in this embodiment), and the operating pressure Pi0. The target pressure calculation unit 145 of this embodiment outputs PiBM3U1 of the target operating pressure Pi1 to the corrected target pressure calculation unit 146.

[0158] 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 by the learning process of the learning unit 149. The valve command calculation unit 147 controls the solenoid valves 55a to 59b based on the target operating pressure Pi1 excluding the corrected target operating pressure PiBM3U2 and the target operating pressure PiBM3U1.

[0159] The learning unit 149 performs the following learning processing: measuring the cylinder pressure of the flow control valve D3 during the execution of the area restriction control, and obtaining the correction value Pic of the operating pressure when the measured cylinder pressure (minimum cylinder pressure Pmin, maximum cylinder pressure Pmax) converges within the range of the predetermined pressure threshold value Pta.

[0160] During the learning process, the cylinder pressure (minimum cylinder pressure Pmin, maximum cylinder pressure Pmax) is measured, and the correction value Pic of the operating pressure is obtained in a manner that converges within the range of a predetermined pressure threshold value Pta. As a result, the pressure loss (brake pressure) caused by throttling of the outlet throttle opening can be converged to the target range.

[0161] According to this structure, the influence of the manufacturing error of the flow control valve D3 can be reduced through learning and correction, the opening characteristics of the flow control valve used in the prototype can be reproduced, and the flow control valve can be controlled. As a result, the claw tip (control point) of the bucket 10 can be moved with high accuracy in area restriction control, etc.

[0162] In addition, the hydraulic system can be set as a central closed system or as Fig.14 The controller 40 of this embodiment calculates the target opening area using the formula of the throttle hole that takes into account the target flow rate (target speed) and the load pressure of the hydraulic cylinders 5 to 7 when the hydraulic cylinders 5 to 7 are to be operated at a predetermined target flow rate (target speed). Therefore, even when the center opening system is adopted in the hydraulic system, the hydraulic cylinders 5 to 7 can be operated at the target flow rate (target speed) regardless of light load, heavy load, etc.

[0163] As described above, according to the present embodiment, regardless of the structure of the hydraulic system, it is possible to suppress the deviation in the operation of the hydraulic cylinder due to the individual difference of the working machine, and it is possible to provide a working machine that can perform work with high precision.

[0164] (2) The learning unit 149 sets at least the posture of the working device 1A as the learning start posture and the excavation target surface St as the learning start target surface as one of the conditions for starting the learning process. Thus, the learning unit 149 can appropriately acquire the correction value Pic, and the corrected target pressure calculation unit 146 can accurately correct the target operating pressure Pi1.

[0165] In the first embodiment, the working machine 1 comprises: a vehicle body 1B; a working device 1A which is rotatably mounted on the vehicle body 1B; a hydraulic cylinder 5 which drives the working device 1A; an operating device A1 which is used to operate the working device 1A; a hydraulic pump 203; a flow control valve D3 which controls the flow of the working oil supplied from the hydraulic pump 203 to the hydraulic cylinder 5; solenoid valves 56a and 56b which generate an operating pressure of the flow control valve D3; and a controller 40 which calculates a target speed of the hydraulic cylinder 5 according to the operation amount of the operating device A1 so that the range of motion of the working device 1A is limited to and above the target surface St, and controls the target speed according to the target surface St. The target operating pressure of the flow control valve D3 is calculated based on the speed, and the solenoid valves 56a and 56b are controlled according to the target operating pressure, wherein the working machine 1 has: pressure sensors 5a and 5b, which are used to measure the outlet throttling pressure of the hydraulic cylinder 5, and the controller 40 calculates the correction value Pic of the target operating pressure, and corrects the target operating pressure according to the correction value Pic, wherein the correction value Pic is used to: converge the outlet throttling pressure measured during the period of driving the hydraulic cylinder 5 to make the working device 1A perform a specified action within the range from a specified first lower limit value Pm1 to a specified first upper limit value Pm2.

[0166] In addition, when the minimum value Pmin of the outlet throttling pressure measured during the period when the working device 1A performs the prescribed action is lower than the first lower limit value Pm1, the controller 40 in the first embodiment calculates the correction value Pic so that the target operating pressure is reduced. When the maximum value Pmax of the outlet throttling pressure measured during the period when the working device 1A performs the prescribed action exceeds the first upper limit value Pm2, the controller 40 in the first embodiment calculates the correction value Pic so that the target operating pressure is increased, and corrects the target operating pressure by increasing or decreasing the target operating pressure according to the correction value Pic.

[0167] According to the first embodiment constructed as described above, by correcting the target operating pressure of the flow control valve D3 so that the outlet throttling pressure of the hydraulic cylinder 5 driving the working device 1A converges within a specified range (Pm1~Pm2), it is possible to prevent the deterioration of the speed responsiveness of the hydraulic cylinder 5 driving the working device 1A, as well as the fluctuation and loss of control of the hydraulic cylinder 5, thereby enabling operations to be performed with high precision.

[0168] In addition, the pressure sensor 5b in the first embodiment detects the meter-in pressure of the hydraulic cylinder 5, and the controller 40 calculates the measured value of the meter-out pressure by multiplying the meter-in pressure detected by the pressure sensor 5b by the pressure-receiving area ratio of the hydraulic cylinder 5. Thus, even if the pressure sensor 5a for detecting the meter-out pressure of the hydraulic cylinder 5 is not provided, the meter-out pressure of the hydraulic cylinder 5 can be measured.

[0169] Example 2

[0170] The second embodiment of the present invention will be described with a focus on the differences from the first embodiment. In the first embodiment, the learning process is performed on the horizontal pull-back operation, but in the present embodiment, the learning process is performed on the boom raising individual operation.

[0171] Fig.15 is a flowchart showing the learning process performed by the learning unit 149 of this embodiment. Fig.16 This shows the learning start posture of this embodiment.

[0172] In this embodiment, Fig.16 The boom angle shown, in which the arm cylinder 6 and the bucket cylinder 7 are maximally extended and the working device 1A is not in contact with the ground, is stored as the boom raising independent learning starting posture, the cylinder pressure during the boom raising independent action is measured, and the measured cylinder pressure is compared with the threshold value to obtain the correction value.

[0173] Reference Fig.15 The learning process of the flow control valve D3 based on the boom raising independent action will be described. When the operator operates the external input device 96 and inputs an execution instruction of the learning process from the external input device 96, the learning unit 149 starts the learning process (step S201).

[0174] In step S201, if reading of the boom-up individual learning start posture data is completed, the process proceeds to step S202.

[0175] In step S202, the display control unit 150 causes the display device 53 to display Fig.16 The boom raising individual learning start posture as shown causes the process to proceed to step S203.

[0176] In step S203, the learning unit 149 determines whether the posture of the working device 1A is the learning start posture. When the current boom angle α, arm angle β, and bucket angle γ are respectively within the target ranges specified by the boom-up individual learning start posture data, the learning unit 149 determines that the posture of the working device 1A is the learning start posture, and the processing proceeds to step S204.

[0177] When at least one of the current boom angle α, arm angle β, and bucket angle γ is outside the target range specified by the boom-up individual learning start posture data, the learning unit 149 determines that the posture of the working device 1A is not the learning start posture. The learning start condition determination process of step S203 is repeatedly executed in a predetermined control cycle until it is determined to be positive.

[0178] In step S203, when the learning start condition determination process is determined to be positive, the display control unit 150 causes the display device 53 to display an operation instruction screen. An operation instruction such as "Please operate the boom operating lever to the raising side" is displayed on the operation instruction screen. In step S203, when the operation instruction screen is displayed, the process proceeds to step S204.

[0179] In step S204, when the operator operates the electric operating lever device A1 to the boom raising side, the learning process starts, and the boom 8 moves to the raising side while the electric operating lever device A1 is operated. In addition, under normal circumstances, when the electric operating lever device A1 is operated, the flow rate of the working oil ejected from the three main pumps 201, 202, and 203 is controlled by the three flow control valves D1, D2, and D3, thereby driving the boom cylinder 5. However, this embodiment focuses on the learning of the flow control valve D3, and therefore, in the learning process, when the electric operating lever device A1 is operated, only a command is given to the electromagnetic valve 56a, and the flow rate of the working oil ejected from the third main pump 203 is controlled by the flow control valve D3, thereby driving the boom cylinder 5.

[0180] The learning unit 149 measures the cylinder pressure when the boom 8 is driven in the upward direction. The learning unit 149 stores the measured cylinder pressure and time. Here, the cylinder pressure to be stored is detected by the pressure sensor 5a.

[0181] In step S204, the learning unit 149 extracts the minimum value Pmin (hereinafter also referred to as the minimum cylinder pressure) and the maximum value Pmax (hereinafter also referred to as the maximum cylinder pressure) of the cylinder pressure from the start to the end of the measurement based on the stored time and the cylinder pressure measured using the pressure sensor 5a, and enters the processing into step S205.

[0182] Thus, in the present embodiment, the cylinder pressure is measured during the boom raising single action, and it is determined whether the measured cylinder pressure is within the range of the pressure threshold value Ptab of the cylinder pressure in the boom raising single action (the minimum threshold value and the maximum threshold value of the cylinder pressure in the boom raising single action) which is predetermined in advance, and a correction value is obtained. In addition, regarding the range of the pressure threshold value Ptab of the cylinder pressure in the boom raising single action based on the learning of the boom raising single action, the cylinder pressure determined by the experiment using theoretical calculation or a prototype is set as a target range (lower limit value and upper limit value) that meets the target based on the opening characteristics stored in advance and the flow rate through the flow control valve D3 in the area limiting control.

[0183] The working device 1A in the second embodiment comprises: a boom 8, which is rotatably mounted on the vehicle body 1B; a dipper arm 9, which is rotatably mounted on the front end of the boom 8; and a bucket 10, which is rotatably mounted on the front end of the dipper arm 9. The hydraulic cylinder 5 that drives the working device 1A is the boom cylinder 5 that drives the boom 8. In order to calculate the correction value of the target operating pressure of the flow control valve D3, the prescribed action of the working device 1A is: without moving the dipper arm 9 or the bucket 10, the boom raising action of lifting the boom 8 is performed alone.

[0184] According to the second embodiment constructed as described above, by measuring the cylinder pressure during the boom raising independent operation, the starting conditions of the learning process can be reduced, the efficiency can be improved, and the learning process can be executed even in an environment where the boom cylinder 6 cannot be fully contracted.

[0185] Example 3

[0186] The third embodiment of the present invention will be described with a focus on the differences from the first embodiment. In the first embodiment, the learning process of the flow control valve D3 corresponding to the boom raising action is described. In contrast, in the present embodiment, the learning process of the flow control valve D4 corresponding to the boom pulling back action is described.

[0187] In this embodiment, in order to suppress the deterioration of the accuracy of the area restriction control caused by the deviation (individual difference) from the opening characteristic table To due to the manufacturing error of the flow control valve D4 corresponding to the boom pull-back action 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 electromagnetic 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 according to the target valve core opening, thereby suppressing the deterioration of the accuracy of the area restriction control caused by the deviation of the manufacturing error.

[0188] In order to learn the relationship between the opening area of ​​the meter-out passage portion of the flow control valve D4 and the operating pressure generated by the solenoid valve 57 a , the load pressure on the meter-out side of the hydraulic cylinder 6 is measured.

[0189] The load pressure on the meter-out side of the hydraulic cylinder 6 in this embodiment is related to the opening area of ​​the meter-out passage portion of the flow control valve D4 and the operating pressure generated by the solenoid valve 57a.

[0190] Therefore, by measuring the load pressure on the meter-out side of the hydraulic cylinder 6, the pressure loss (brake pressure) caused by throttling can be measured, and the relationship between the opening area of ​​the meter-out passage portion of the flow control valve D4 and the operating pressure generated by the electromagnetic valve 57a can be learned. In addition, as a method of measuring the pressure loss (brake pressure) caused by throttling, in addition to the method of directly detecting the load pressure on the meter-out side of the hydraulic cylinder 6, there is also a method of multiplying the load pressure on the meter-in side of the hydraulic cylinder 6 by the pressure-receiving area ratio of the hydraulic cylinder 6.

[0191] Reference Fig.17 , the flow of the learning process of the flow control valve D4 executed by the learning unit 149 is described. Fig.17 30 is a flowchart showing the learning process of the flow control valve D4 executed by the learning unit 149. When an operator operates the external input device 96 and an execution instruction of the learning process is input from the external input device 96, the learning unit 149 starts the learning process (step S301).

[0192] In step S301 , the learning unit 149 reads out the learning start posture data and the learning start target surface data related to the learning of the flow control valve D4 from the nonvolatile memory 42 .

[0193] In this embodiment, if Fig.10 As shown, the starting posture and target surface of the horizontal pullback are set. The range is set in such a way that the arm angle β of the learning starting posture data becomes the angle at which the arm cylinder 6 is maximally contracted and the bucket angle γ becomes 0 degrees as the target angle. The learning starting target surface data is parallel to the X-axis of the excavator 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. In addition, the target angle of the boom angle α becomes the angle of the boom angle α when the boom angle β and the bucket angle γ meet the above target range and the claw tip of the bucket 10 is consistent with the target surface, and the target range is set according to the target angle of the boom angle α.

[0194] In step S301, if the reading of the learning start posture data and the learning start target surface data is completed, the process proceeds to step S302. Fig.17 As shown, the display control unit 150 causes the display device 53 to display the learning start posture screen 53a (see Fig.11 ).like Fig.11 As shown, a message “Please adjust the posture of the working device to the target range” is displayed on the learning start posture screen 53 a to prompt the operator to perform an operation for changing the posture of the working device 1A to the learning start posture.

[0195] exist Fig.17In step S302, when the learning start posture screen 53a is displayed on the display device 53, the process proceeds to step S303. In step S303, it is determined whether the learning start conditions (learning start posture, learning start target surface, and setting of MC execution mode) are satisfied.

[0196] The determination of the learning start posture is to determine whether the posture of the working device 1A is the learning start posture. When the current boom angle α, arm angle β, and bucket angle γ are respectively within the specified target range, the learning unit 149 determines that the posture of the working device 1A is the learning start posture. When any one 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 working device 1A is not the learning start posture.

[0197] The determination of the learning start target surface is a determination of whether the excavation target surface St is the learning start target surface. When the excavation target surface St is within the target range specified by the learning start target surface data, the learning unit 149 determines that the excavation target surface St is the learning start target surface, and when the excavation target surface St is outside the target range specified by the learning start target surface data, the learning unit 149 determines that the excavation target surface St is not the learning start target surface.

[0198] Determining the setting of the MC execution mode is to determine whether the mode is set to execute the MC. When the mode is set to execute the MC by the mode switching switch operated by the operator, the learning unit 149 determines that the mode is set to execute the MC, and when the mode is not set to execute the MC by the mode switching switch operated by the operator, the learning unit 149 determines that the mode is not set to execute the MC.

[0199] In step S303, when all the learning start conditions (learning start posture, learning start target surface, MC execution mode setting) are determined to be positive, the process proceeds to step S304. The determination of the learning start conditions (learning start posture, learning start target surface, MC execution mode setting) in step S303 is repeatedly performed in a predetermined control cycle until it is determined to be positive.

[0200] In step S303, when the judgment process of the learning start condition is judged to be positive, the display control unit 150 causes the display device 53 to display the operation instruction screen. The operation instruction screen displays an operation instruction such as "Please operate the boom operating lever to the pull-back side". In step S303, when the operation instruction screen is displayed, the process proceeds to step S304.

[0201] In step S304, when the operator operates the electric operating lever device A2 to pull the boom back, the learning process starts. While the electric operating lever device A2 is being operated, the area restriction control is performed to control the movement of the working device 1A so that the front end of the bucket 10 moves along the excavation target surface St.

[0202] The learning unit 149 performs area restriction control and measures the load pressure on the outlet throttle side of the hydraulic cylinder 6 when the boom 9 is driven in the boom pulling direction. In addition, the load pressure on the outlet throttle side of the hydraulic cylinder 6 is also hereinafter referred to as the boom cylinder pressure. The learning unit 149 stores the measured boom cylinder pressure and time. Here, the stored boom cylinder pressure is detected by the pressure sensor 6a.

[0203] In step S304, the learning unit 149 extracts the minimum value Pamin (hereinafter also referred to as the minimum arm cylinder pressure) and the maximum value Pamax (hereinafter also referred to as the maximum arm cylinder pressure) of the arm cylinder pressure from the start to the end of the measurement based on the stored time and the arm cylinder pressure measured using the pressure sensor 6a, and enters the processing into step S305.

[0204] In step S305, the learning unit 149 determines whether the minimum boom cylinder pressure Pamin calculated in step S304 is greater than a predetermined minimum boom cylinder pressure threshold value Pm3. The minimum boom cylinder pressure threshold value Pm3 is a lower limit value when a target range (lower limit value and upper limit value) that satisfies the target value is set based on the cylinder pressure determined by theoretical calculation or experiments using a prototype, etc., based on the pre-stored opening characteristics and the flow rate through the flow control valve D4 in the area restriction control.

[0205] When it is determined in step S305 that the minimum arm cylinder pressure Pamin is smaller than the minimum threshold value Pm3 of the arm cylinder pressure, the learning unit 149 advances the process to step S307.

[0206] In step S307, the learning unit 149 obtains the arm correction value Pica for reducing 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, when the initial value of the correction value Pica is set to 1.00, in order to reduce the operating pressure, 0.01 is added from the initial value to make the correction value Pica 1.01.

[0207] The learning unit 149 outputs the acquired boom correction value Pica to the correction target pressure calculation unit, and returns the process to step S302. That is, when measuring the next boom cylinder pressure, the target operating pressure PiAM1C1 is corrected by 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.

[0208] When it is determined in step S305 that the minimum arm cylinder pressure Pamin is greater than the minimum threshold value Pm3 of the arm cylinder pressure, the learning unit 149 advances the process to step S306 .

[0209] In step S306, the learning unit 149 determines whether the maximum boom cylinder pressure Pamax calculated in step S304 is less than a predetermined maximum boom cylinder pressure threshold value Pm4. The maximum boom cylinder pressure threshold value Pm4 is an upper limit value as follows: based on the pre-stored opening characteristics and the flow rate through the flow control valve D4 in the area restriction control, the cylinder pressure determined by the theoretical calculation or the experiment using the prototype is used as the target value, and the upper limit value is set when the target range (lower limit value and upper limit value) that meets the target value is set.

[0210] When it is determined in step S306 that the maximum arm cylinder pressure Pamax is greater than the maximum cylinder pressure threshold value Pm4, the learning unit 149 advances the process to step S308.

[0211] In step S308, the learning unit 149 adds the correction value Pica of the operating pressure to obtain the arm correction value Pica for increasing the operating pressure. For example, when the initial value of the correction value Pic is set to 1.00, 0.01 is added to the initial value to increase the operating pressure, and the correction value Pic is set to 1.01.

[0212] The learning unit 149 outputs the acquired boom correction value Pica to the correction target pressure calculation unit, and returns the process to step S302. That is, when measuring the next cylinder pressure, the target operating pressure PiAM1C1 is corrected by 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.

[0213] In step S306, if it is determined that the maximum arm cylinder pressure Pamax is less than the maximum threshold value Pm of the arm cylinder pressure, the learning unit 149 advances the process to step S309. In step S309, the learning unit 149 stores the arm correction value Pica of the operating pressure and ends. Fig. 9 In addition, the display control unit 150 causes the display device 53 to display that the learning process has been completed.

[0214] Thus, in the learning process, the learning unit 149 measures the boom cylinder pressure during the execution of the area restriction control, and obtains the boom correction value Pica when it converges to the range of the pressure threshold value Ptaa of the boom cylinder pressure (the minimum threshold value Pm3 of the boom cylinder pressure, the maximum threshold value Pm4 of the boom cylinder pressure). The obtained boom correction value Pica is used in the correction process.

[0215] In addition, in this embodiment, if Fig.12 As shown in the figure, the measured boom cylinder pressure becomes smaller than the minimum threshold value Pm3 of the boom cylinder pressure after the operator operates the electric operating lever device A2 to the boom pull-back side and executes the area restriction control and near the end of the boom pull-back action. When the measured boom cylinder pressure is smaller than the minimum threshold value Pm3 of the boom cylinder pressure, the above operation is repeated. Fig.17 The process goes from step S305 to step S307.

[0216] 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 the threshold value Vtaa. That is, the arm cylinder pressure is measured by excluding the arm cylinder pressure after the execution of the area restriction control and near the end of the boom pull-back action, thereby preventing the process from mistakenly entering step S305 to step S307 repeatedly. In addition, the condition for starting the arm cylinder pressure measurement may not be the threshold value for the secondary target speed, as long as the arm cylinder pressure after the execution of the area restriction control and near the end of the boom raising action can be measured.

[0217] Reference Fig.18 The correction process will be described. Fig.18 The correction process performed by the correction target pressure calculation unit 146 is shown. Here, the target operating pressure PiAM1C1 is calculated by the target pressure calculation unit 145, and the boom correction value Pica is obtained by the learning unit 149. The correction target pressure calculation unit 146 receives the target operating pressure PiAM1C1 output by the target pressure calculation unit 145, and reads the boom correction value Pica obtained by the learning unit 149. In this embodiment, in order to perform the learning process for the flow control valve D4, in the correction process, 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 instruction calculation unit 147 becomes the target operating pressure Pi1 (PiBM12U1, PiBM3U1, PiBM12D1, PiBM3D1, PiAM2C1, PiAM1D1, PiAM2D1, PiBKC1, PiBKD1) excluding the target operating pressure PiAM1Cl.

[0218] The corrected target pressure calculation unit 146 calculates the corrected target operating pressure Pi2 by multiplying the target operating pressure PiAM1C1 by the arm correction value Pica, and outputs the calculated corrected target operating pressure to the valve command calculation unit 147 .

[0219] According to the third embodiment described above, the following effects are achieved.

[0220] (1) The target pressure calculation unit 145 calculates the target value (target operating pressure) Pi1 of the operating pressure generated by the solenoid valves 55a to 59b based on the opening characteristic table To, the target valve core opening (Aout in this embodiment), and the operating pressure Pi0. The target pressure calculation unit 145 of this embodiment outputs PiAM1C1 of the target operating pressure Pi1 to the corrected target pressure calculation unit 146.

[0221] 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 by the learning process of the learning unit 149. The valve command calculation unit 147 controls the solenoid valves 55a to 59b based on the target operating pressure Pi1 excluding the corrected target operating pressure PiAM1C2 and the target operating pressure PiAM1C1.

[0222] The learning unit 149 performs the following learning processing: measuring the boom cylinder pressure of the flow control valve D4 during the execution of the area restriction control, and obtaining the boom correction value Pica when the measured boom cylinder pressure (minimum boom cylinder pressure Pamin, maximum boom cylinder pressure Pamax) converges within the range of the predetermined boom cylinder pressure threshold value Ptaa (minimum cylinder pressure threshold value Pm3, maximum cylinder pressure threshold value Pm4).

[0223] During the learning process, the cylinder pressure (minimum boom cylinder pressure Pamin, maximum boom cylinder pressure Pamax) is measured, and the correction value Pica of the operating pressure is obtained in a manner that converges within the range of a predetermined pressure threshold value Ptaa. As a result, the pressure loss (brake pressure) caused by throttling of the outlet throttle opening can be converged to the target range.

[0224] According to this structure, the influence of the manufacturing error of the flow control valve D4 can be reduced by learning and correction, the opening characteristics of the flow control valve used in the prototype can be reproduced, and the flow control valve can be controlled. As a result, the claw tip (control point) of the bucket 10 can be moved with high precision in area restriction control, etc.

[0225] In addition, the hydraulic system can be set as a central closed system or as Fig.14 The controller 40 of this embodiment calculates the target opening area using the formula of the throttle hole that takes into account the target flow rate (target speed) and the load pressure of the hydraulic cylinders 5 to 7 when the hydraulic cylinders 5 to 7 are to be operated at a predetermined target flow rate (target speed). Therefore, even when the center opening system is adopted in the hydraulic system, the hydraulic cylinders 5 to 7 can be operated at the target flow rate (target speed) regardless of light load, heavy load, etc.

[0226] As described above, according to the present embodiment, regardless of the structure of the hydraulic system, it is possible to suppress the deviation in the operation of the hydraulic cylinder due to the individual difference of the working machine, and it is possible to provide a working machine that can perform work with high precision.

[0227] (2) The learning unit 149 sets at least the posture of the working device 1A as the learning start posture and the excavation target surface St as the learning start target surface as one of the conditions for starting the learning process. Thus, the learning unit 149 can appropriately obtain the arm correction value Pica, and the correction target pressure calculation unit 146 can accurately correct the target operating pressure Pi1.

[0228] In addition, when the learning process of the third embodiment is performed after the learning process of the first embodiment or the second embodiment, in addition to the manufacturing error of the flow control valve D3 corresponding to the boom raising action, the deterioration of the accuracy of the area restriction control caused by the manufacturing error of the flow control valves D4 and D5 corresponding to the boom pulling back action can be suppressed, and a working machine capable of operating with high accuracy can be provided. In addition, the learning process of the first embodiment or the second embodiment can be performed after the learning process of the third embodiment is performed.

[0229] In the third embodiment, the working machine 1 comprises: a vehicle body 1B; a working device 1A which is rotatably mounted on the vehicle body 1B; a hydraulic cylinder 6 which drives the working device 1A; an operating device A2 which is used to operate the working device 1A; a hydraulic pump 202; a flow control valve D4 which controls the flow of the working oil supplied from the hydraulic pump 202 to the hydraulic cylinder 6; electromagnetic valves 57a and 57b which generate an operating pressure for the flow control valve D4; a controller 40 which calculates a target speed of the hydraulic cylinder 6 according to the operation amount of the operating device A2 so that the motion range of the working device 1A is limited to the target surface St and above it, and controls the working device 1A according to the target speed. The target operating pressure of the flow control valve D4 is calculated, and the solenoid valves 57a and 57b are controlled according to the target operating pressure, wherein the working machine 1 has: pressure sensors 6a and 6b, which are used to measure the outlet throttling pressure of the hydraulic cylinder 6, and the controller 40 calculates the correction value Pica of the target operating pressure, and corrects the target operating pressure according to the correction value Pica, wherein the correction value Pica is used to: converge the outlet throttling pressure measured during the period of driving the hydraulic cylinder 6 to make the working device 1A perform a specified action within the range from a specified first lower limit value Pm3 to a specified first upper limit value Pm4.

[0230] In addition, when the minimum value Pmin of the outlet throttling pressure measured during the period when the working device 1A performs the prescribed action is lower than the first lower limit value Pm3, the controller 40 in the third embodiment calculates the correction value Pica so that the target operating pressure is reduced. When the maximum value Pmax of the outlet throttling pressure measured during the period when the working device 1A performs the prescribed action exceeds the first upper limit value Pm4, the controller 40 in the third embodiment calculates the correction value Pica so that the target operating pressure is increased, and corrects the target operating pressure by increasing or decreasing the target operating pressure according to the correction value Pica.

[0231] According to the third embodiment constructed as described above, by correcting the target operating pressure of the flow control valve D4 so that the outlet throttling pressure of the hydraulic cylinder 6 driving the working device 1A converges within a specified range (Pm3~Pm4), it is possible to prevent the deterioration of the speed responsiveness of the hydraulic cylinder 6 driving the working device 1A, as well as the fluctuation and loss of control of the hydraulic cylinder 6, thereby enabling operations to be performed with high precision.

[0232] In addition, the pressure sensor 6b in the third embodiment detects the meter-in pressure of the hydraulic cylinder 6, and the controller 40 calculates the measured value of the meter-out pressure by multiplying the meter-in pressure detected by the pressure sensor 6b by the pressure-receiving area ratio of the hydraulic cylinder 6. Thus, even if the pressure sensor 6a for detecting the meter-out pressure of the hydraulic cylinder 6 is not provided, the meter-out pressure of the hydraulic cylinder 6 can be measured.

[0233] In addition, the working device 1A in the third embodiment includes: a boom 8 rotatably mounted on the vehicle body 1B; an arm 9 rotatably mounted on the front end of the boom 8; a bucket 10 rotatably mounted on the front end of the arm 9, and the hydraulic cylinder 6 is an arm cylinder 6 for driving the arm 9. The prescribed action is a horizontal retraction action of pulling the bucket 10 closer in a manner that the claw tip of the bucket 10 moves along a target surface St set parallel to the ground. Thus, a horizontal estimation action can be performed with high accuracy.

[0234] Example 4

[0235] The fourth embodiment of the present invention will be described with a focus on the differences from the first embodiment. The pressure on the meter-in side and the meter-out side of the hydraulic cylinder 5 vary according to the temperature of the working oil. Therefore, the controller 40 of this embodiment performs the learning process only when the temperature of the working oil is above a predetermined temperature threshold.

[0236] Fig.19 is a flowchart showing the learning process performed by the learning unit 149 of this embodiment. Fig.19 In the first embodiment ( Fig. 9The difference between the above and the above is that step S401 is added after step S102.

[0237] In step S401, the learning unit 149 determines whether the temperature Te of the working oil detected by the temperature sensor 19 is greater than or equal to the temperature threshold value Tte. The temperature threshold value Tte is pre-stored in the non-volatile memory 42. If the determination result of step S401 is negative, the process proceeds to step S102, and if the determination result is positive, the process proceeds to step S103. The determination process of step S401 is repeatedly executed in a predetermined control cycle until the determination is positive.

[0238] Thus, in this embodiment, the posture of the working device 1A is the learning start posture, the learning start target surface is set, the MC execution mode is set, and the temperature Te of the working oil is greater than the temperature threshold Tte as conditions for starting the learning process. Thus, at least the temperature Te of the working oil is greater than the temperature threshold Tte as one of the conditions for starting the learning process (steps S104 to S109), thereby preventing the learning process from being performed when the temperature Te of the working oil is less than the temperature threshold Tte. Thus, the change in the pressure on the meter-out side caused by the temperature of the working oil can be prevented, so the change in the learning result caused by the temperature of the working oil can be suppressed, and the accuracy of the area restriction control can be improved.

[0239] The working machine 1 in the fourth embodiment includes the temperature sensor 19 for detecting the temperature Te of the hydraulic oil. The controller 40 calculates the correction value Pic when the temperature Te of the hydraulic oil detected by the temperature sensor 19 is equal to or higher than a predetermined threshold value Tte.

[0240] According to the fourth embodiment configured as above, it is possible to prevent the pressure change on the meter-out side due to the working oil temperature, thereby suppressing the change in the learning result due to the working oil temperature and improving the accuracy of the range limiting control.

[0241] Example 5

[0242] The fifth embodiment of the present invention will be described with the differences from the first embodiment as the center. 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 excavator 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 is also possible to have an angle with respect to the X-axis of the excavator reference coordinate system of the working device 1A. In addition, it is set as the range in which the flow control valve to be learned moves.

[0243] Example 6

[0244] The sixth embodiment of the present invention will be described focusing on the differences from the first embodiment. Fig. 20 is a flowchart showing the learning process performed by the learning unit 149 of this embodiment. Fig. 20 In the first embodiment ( Fig. 9 The difference between the above and the above is that steps S501 to S503 are executed instead of steps S105 and S106.

[0245] Following step S104 , in step S501 , the learning unit 149 calculates an average value Pav (hereinafter also referred to as average cylinder pressure) of the cylinder pressure on the meter-out side measured in step S104 , and the process proceeds to step S502 .

[0246] In step S502 , the learning unit 149 determines whether the average cylinder pressure Pav is equal to or greater than the lower limit threshold value Pav1 . If the determination result in step S502 is NO, the process proceeds to step S107 , and if the determination result is YES, the process proceeds to step S503 .

[0247] In step S503 , the learning unit 149 determines whether the average cylinder pressure Pav is equal to or less than the upper limit threshold value Pav2 . If the determination result is NO , the process proceeds to step S108 , and if the determination result is YES , the process proceeds to step S109 .

[0248] In addition, the lower limit threshold value Pav1 and the upper limit threshold value Pav2 are based on the opening characteristics of the flow control valve D3 stored in advance and the flow rate of the flow control valve D3 in the area limitation control, and the cylinder pressure determined according to the experiment using theoretical calculations or prototypes is used as the target value, and the lower limit value and upper limit value are set when the target range (lower limit value and upper limit value) that meets the target value is met.

[0249] Thus, in this embodiment, the average cylinder pressure Pav is compared with the lower limit threshold value Pav1 of the cylinder pressure average value and the upper limit threshold value Pav2 of the cylinder pressure average value to obtain the correction value Pic of the operating pressure. The correction value Pic is calculated based on the average cylinder pressure Pav, thereby allowing for learning processing to be performed in consideration of temporary cylinder pressure reduction or increase, deviation, etc. during cylinder pressure measurement, thereby preventing the cylinder pressure from being adjusted. Fig. 20 Entering the wrong step in the process.

[0250] In addition, in the learning process ( Fig. 9 In the embodiment shown in FIG. 1 , there is a step of comparing the measured cylinder pressure with the minimum cylinder pressure threshold value Pm1 and the maximum cylinder pressure threshold value Pm2 to make a judgment. In the embodiment, there is a step of comparing the lower limit threshold value Pav1 of the cylinder pressure average value with the upper limit threshold value Pav2 of the cylinder pressure average value to make a judgment. Among them, it can be any one or any combination, and by combining, it can prevent entering the wrong step in the process.

[0251] The controller 40 in the sixth embodiment calculates the average value Pav of the outlet throttling pressure of the boom cylinder 5 measured during the period when the working device 1A performs a specified action. When the average value Pav is lower than the specified second lower limit value Pav1, the correction value Pic is calculated in a manner that reduces the target operating pressure of the flow control valve D3. When the average value Pav exceeds the second upper limit value Pav2, the correction value is calculated in a manner that increases the target operating pressure.

[0252] According to the sixth embodiment constructed as above, the correction value Pic is calculated based on the average cylinder pressure Pav, thereby making it possible to perform learning processing in consideration of temporary cylinder pressure reduction or increase, deviation, etc. during cylinder pressure measurement, thereby preventing the cylinder pressure from being reduced or increased. Fig. 20 Entering the wrong step in the process.

[0253] Example 7

[0254] The seventh embodiment of the present invention will be described with a focus on the differences from the first embodiment. In the correction process performed by the correction target pressure calculation unit 146 of the first embodiment, the target pressure calculation unit 145 receives the target operating pressure PiBM3U1 corresponding to the flow control valve D3 and the correction value Pic of the operating pressure obtained by the learning process of the learning unit 149, as shown in FIG. Fig.13 As shown in FIG. 1 , the target operating pressure PiBM3U2 is obtained by multiplying the pressure by 1. Fig.21 As shown in FIG. 1 , the corrected target operating pressure PiBM3U2 may be calculated by adding the corrected value Pic of the operating pressure to the target operating pressure PiBM3U1. Fig.21 As shown in FIG. 1 , when the correction target operating pressure PiBM3U2 is calculated by the addition method, the initial value of the correction value Pic is set to 0.00. Fig. 9 In S108 of FIG. 107 , if the command pressure is to be increased, 0.01 is added to the initial value according to the learning step. Fig. 9 In S107, when the operating pressure is to be reduced, 0.01 is subtracted from the initial value. In addition, the method of correcting the target operating pressure based on the correction value Pic is not limited to the method of multiplying or adding the correction value Pic to the target operating pressure.

[0255] Example 8

[0256] The eighth embodiment of the present invention will be described with the differences from the first embodiment as the center. Regarding the learning process described in the first embodiment, the smaller the deviation of the discharge flow rate of the main pumps 201, 202, 203 corresponding to the regulator pressure from the target flow rate (design value) Qc, the higher the accuracy. Therefore, it is preferable to correct the target operating pressure with respect to the target opening area of ​​the flow control valves D1 to D6 after correcting the discharge flow rate of the main pumps 201, 202, 203 (learning and correction). In the case where the discharge flow rate of the main pumps 201, 202, 203 deviates from the target flow rate (design value) Qc, the measured cylinder pressure also deviates, and it is impossible to know whether the opening area corresponding to the target pressure (pressure threshold of the boom cylinder pressure) Ptaa is obtained. Therefore, in this embodiment, the learning process is performed on the flow control valves D1 to D6 on the basis of setting the discharge flow rate of the main pumps 201, 202, 203 to discharge the working oil substantially according to the design value. In this way, the accuracy of the learning process can be improved.

[0257] Example 9

[0258] The ninth embodiment of the present invention will be described with a focus on the differences from the above-mentioned embodiments. In the above-mentioned embodiments, when performing the learning process, working oil is sometimes supplied from one hydraulic pump to a plurality of hydraulic cylinders. On the other hand, in MC, it is particularly important to drive the hydraulic cylinder at the target speed, and one hydraulic cylinder is driven by one hydraulic pump (to prevent diversion), thereby improving the excavation accuracy. Therefore, it is preferred that the learning process is also performed under the same conditions. Therefore, in this embodiment, when performing the learning process, the hydraulic cylinder to which working oil is supplied from one hydraulic pump is limited to one.

[0259] The working device 1A in the ninth embodiment has a boom 8 that can be rotatably mounted on the vehicle body 1B and an arm 9 that can be rotatably mounted on the front end of the boom 8, the hydraulic cylinders 5 and 6 that drive the working device 1A include a boom cylinder 5 that drives the boom 8 and an arm cylinder 6 that drives the arm 9, the hydraulic pumps 202 and 203 include a first hydraulic pump 203 of a variable capacity type that preferentially supplies working oil to the boom cylinder 5 and a second hydraulic pump 202 of a variable capacity type that preferentially supplies working oil to the arm cylinder 6, and the flow control valves D3 and D4 include a first flow control valve D3 that controls the flow rate of the working oil supplied from the first hydraulic pump 203 to the boom cylinder 5 and a second hydraulic pump 202 of a variable capacity type that preferentially supplies working oil to the arm cylinder 6, and the flow control valves D3 and D4 include a first flow control valve D3 that controls the flow rate of the working oil supplied from the first hydraulic pump 203 to the boom cylinder 5 and a second hydraulic pump 202 that controls the flow rate of the working oil supplied from the second hydraulic pump 202 to the arm cylinder 6. The second flow control valve D4, the solenoid valves 56a~57b include a first solenoid valve 56a, 56b that generates an operating pressure for the first flow control valve D3 and a second solenoid valve 57a, 57b that generates an operating pressure for the second flow control valve D4, the controller 40 uses the outlet throttling pressure of the boom cylinder 5 measured during the operation of the working device 1A to drive only the first flow control valve D3 to calculate the correction value Pic of the target operating pressure of the first solenoid valves 56a, 56b, and uses the outlet throttling pressure of the boom cylinder 6 measured during the operation of the working device 1A to drive only the second flow control valve D4 to calculate the correction value Pica of the target operating pressure of the second solenoid valves 57a, 57b.

[0260] According to the ninth embodiment constructed as described above, the accuracy of the area limitation control can be improved by calculating the correction values ​​Pic and Pica for the action of driving one hydraulic cylinder with one hydraulic pump.

[0261] The embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments, and also includes various modified examples. For example, the above embodiments are described in detail to explain the present invention in an easy-to-understand manner, and the present invention is not limited to having all the structures described. In addition, a part of the structure of another embodiment may be added to the structure of a certain embodiment, a part of the structure of a certain embodiment may be deleted, or replaced with a part of another embodiment.

[0262] Explanation of symbols

[0263] 1…Hydraulic excavator (working machine), 1A…Working device, 1B…Car body, 5…Boom cylinder (hydraulic cylinder), 5a, 5b…Pressure sensor, 6…Arm cylinder (hydraulic cylinder), 6a, 6b…Pressure sensor, 7…Bucket cylinder, 7a, 7b…Pressure sensor, 8…Boom, 9…Arm, 10…Bucket, 11…Traveling body, 12…Swinging body, 13…Bucket link, 14…Car body position detection device, 14a…GNSS antenna, 14b…GNSS antenna, 15…Control valve unit, 16…Operator's cab, 18…Engine, 19…Temperature sensor, 21…Control 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 device, 42… non-volatile memory, 43… volatile memory, 44… input interface, 45… output interface, 48… pilot pump, 50… posture detection device, 51… target surface setting device, 53… display device, 53a… learning start posture screen, 55a, 55b… solenoid valve, 56a, 56b… solenoid valve (first 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…operation amount calculation unit, 142…posture calculation unit, 143…target surface calculation unit, 144…target speed calculation unit, 145…target pressure calculation unit, 146…corrected target pressure calculation unit, 147…valve command calculation unit, 148…solenoid valve control unit, 149…learning unit, 150…display control unit, 170…discharge pipe, 201…first main pump, 201a…regulator, 201b…pressure Force sensor, 202…second main pump (second hydraulic pump), 202a…regulator, 202b…pressure sensor, 203…third main pump (first hydraulic pump), 203a…regulator, 203b…pressure sensor, A1~A3…electric operating lever device, B1, B2…operating lever, C1~C12…pilot line, D1, D2…flow control valve, D3…flow control valve (first flow control valve), D4…flow control valve (second flow control valve), D5, D6…flow control valve, E1~E12…pressure receiving chamber, St…excavation target surface, To…opening characteristic table.

Claims

1. A working machine, characterized in that: have: Car body; A working device rotatably mounted on the vehicle body; A hydraulic cylinder that drives the working device; An operating device, used to operate the working device; Hydraulic pumps; a flow control valve that controls the flow rate of the hydraulic oil supplied from the hydraulic pump to the hydraulic cylinder; a solenoid valve that generates an operating pressure for the flow control valve; as well as A controller, which calculates a target speed of the hydraulic cylinder according to the operation amount of the operating device so that the range of motion of the working device is limited to a target surface and above it, and calculates a target operating pressure of the flow control valve according to the target speed, and controls the solenoid valve according to the target operating pressure. The working machine has: a pressure sensor for measuring an outlet throttle pressure of the hydraulic cylinder, The controller calculates a correction value of the target operating pressure and corrects the target operating pressure based on the correction value, wherein the correction value is used to converge the outlet throttling pressure measured during the period when the hydraulic cylinder is driven to cause the working device to perform a specified action within a range from a specified first lower limit value to a specified first upper limit value.

2. The working machine according to claim 1, characterized in that: When the minimum value of the meter-out pressure measured while the working device is performing the predetermined operation is lower than the first lower limit value, the controller calculates the correction value so as to reduce the target operating pressure. When the maximum value of the throttle-out pressure measured while the working device is performing the prescribed action exceeds the first upper limit value, the controller calculates the correction value so as to increase the target operating pressure, and corrects the target operating pressure by increasing or decreasing the target operating pressure according to the correction value.

3. The working machine according to claim 1, characterized in that: The controller calculates an average value of the meter-out pressures measured while causing the working device to perform the predetermined operation. When the average value is lower than a predetermined second lower limit value, the controller calculates the correction value so that the target operating pressure is reduced. The controller calculates the correction value so that the target operating pressure increases when the average value exceeds a prescribed second upper limit value.

4. The working machine according to claim 1, characterized in that: The pressure sensor detects the inlet throttle pressure of the hydraulic cylinder. The controller calculates a measured value of the meter-out pressure by multiplying the meter-in pressure detected by the pressure sensor by a pressure-receiving area ratio of the hydraulic cylinder.

5. The working machine according to claim 1, characterized in that: The working machine includes: a temperature sensor for detecting the temperature of the working oil; The controller calculates the correction value when the temperature of the hydraulic oil detected by the temperature sensor is equal to or higher than a predetermined threshold value.

6. The working machine according to claim 1, characterized in that: The working device comprises: a boom rotatably mounted on the vehicle body; an arm rotatably mounted on a front end of the boom; and a bucket rotatably mounted on a front end of the arm. The hydraulic cylinder is a boom cylinder driving the boom or an arm cylinder driving the arm, The predetermined operation is a horizontal pulling-back operation of pulling the bucket closer so that the claw tip of the bucket moves along the target plane set parallel to the ground.

7. The working machine according to claim 1, characterized in that: The working device comprises: a boom rotatably mounted on the vehicle body; an arm rotatably mounted on a front end of the boom; and a bucket rotatably mounted on a front end of the arm. The hydraulic cylinder is a boom cylinder that drives the boom. The predetermined operation is a boom-up independent operation of lifting the boom without operating the arm or the bucket.

8. The working machine according to claim 1, characterized in that: The working device comprises: a boom rotatably mounted on the vehicle body; and an arm rotatably mounted on the front end of the boom. The hydraulic cylinder includes: a boom cylinder for driving the boom, and an arm cylinder for driving the arm. The hydraulic pump includes a first variable displacement hydraulic pump that supplies hydraulic oil to the boom cylinder with priority, and a second variable displacement hydraulic pump that supplies hydraulic oil to the arm cylinder with priority. The flow control valve includes: a first flow control valve for controlling the flow rate of the hydraulic oil supplied from the first hydraulic pump to the boom cylinder, and a second flow control valve for controlling the flow rate of the hydraulic oil supplied from the second hydraulic pump to the arm cylinder. The electromagnetic valve includes: a first electromagnetic valve generating an operating pressure for the first flow control valve, and a second electromagnetic valve generating an operating pressure for the second flow control valve. When the predetermined action is an action of driving only the first flow control valve, the controller calculates a correction value of a target operating pressure of the first solenoid valve. When the predetermined operation is an operation of driving only the second flow control valve, the controller calculates a correction value of a target operating pressure of the second solenoid valve.

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