Work machine

Abstract

To provide a work machine which suppresses an influence of accumulation of errors included in a control object element to static characteristics and dynamic characteristics of a control object element to operation input, and thereby can improve control robustness, in a hydraulic driving system.SOLUTION: A controller 114 includes: a current behavior prediction unit 114l for predicting the behaviors of electromagnetic valves 113a to 113e in current performance of a hydraulic driving system 902, in response to an operation signal input from operation devices 115a and 115b; a reference behavior prediction unit 114m for predicting the behaviors of the electromagnetic valves 113a to 113e in the reference performance of the hydraulic driving system 902, in response to the operation signal input from the operation devices 115a and 115b; and an electromagnetic valve target command pressure correction unit 114d for correcting the control signal so that the prediction result of the current behavior prediction unit 114l is closer to the prediction result of the reference behavior prediction unit 114m.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a work machine such as a hydraulic excavator. [Background technology]

[0002] Generally, a hydraulic drive system for a hydraulically powered work machine is composed of multiple hydraulic pumps, multiple hydraulic actuators, and multiple flow control valves for controlling the hydraulic fluid supplied from the multiple hydraulic pumps to the multiple hydraulic actuators. These hydraulic components are generally directly controlled mechanically. For example, the movement of an operating lever mechanically affects the operation of a hydraulic valve, and the hydraulic pressure command generated thereby determines the operation amount of the hydraulic components, such as the pump and valve. In recent years, electronically controlled hydraulic drive systems have been developed that control the hydraulic components using electrical signals instead of mechanical control of the hydraulic components.

[0003] In an electronically controlled hydraulic drive system, an input command can be converted into an electric current or a signal that drives the operation of hydraulic components, and by controlling the operating characteristics of the hydraulic components with a controller, it is easy to operate in various operation modes and implement a variety of functions.However, an electronically controlled hydraulic drive system has a problem in that there are many components between the input of an operation command and the drive of the hydraulic components, and the accumulation of errors caused by the performance variations and nonlinear characteristics of these components can easily lead to a large deviation between the desired operation of the work machine and the hydraulic components and their actual operation.

[0004] An example of a document disclosing prior art for solving this problem is Patent Document 1. Patent Document 1 describes a method for accurately controlling a work machine according to a target speed by using a training data set constructed based on operating characteristics measured for the operating conditions of a hydraulic valve and a machine learning system to generate a predicted displacement map of the hydraulic valve in response to a command, and then using this map to calculate a control command for the hydraulic valve according to the target speed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special table 2022-532740 publication Summary of the Invention [Problem to be solved by the invention]

[0006] However, while the method using the predicted displacement map described in Patent Document 1 can suppress the effects of accumulated errors caused by performance variations and nonlinear characteristics of the components of the hydraulic drive system in the static characteristics, that is, the characteristics of the hydraulic valve's displacement in response to a command in a steady state that does not include a time element, it cannot suppress the effects of accumulated errors in the dynamic characteristics, that is, the characteristics of the hydraulic valve's displacement while it is displacing toward a target value that changes over time.As a result, under operating conditions in which the dynamic characteristics of the hydraulic valve vary, a discrepancy may occur between the target actuator speed and the actual actuator speed when the hydraulic actuator is started or when accelerating or decelerating, making it impossible to accurately control the position of a working device such as a bucket.

[0007] The present invention has been made in view of the above-mentioned problems, and its object is to provide a work machine in a hydraulic drive system that is capable of improving control robustness by suppressing the effect of accumulated errors contained in controlled elements on the static and dynamic characteristics of the controlled elements in response to operation inputs. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides a working machine comprising: a vehicle body, a working implement attached to the vehicle body, a hydraulic actuator that drives the working implement, a hydraulic drive system that drives the hydraulic actuator, an operating device that instructs the operation of the hydraulic actuator, and a controller that controls the hydraulic drive system in response to an operation signal input from the operating device, wherein the controller has a target control amount calculation unit that calculates a target control amount of a controlled element of the hydraulic drive system based on the operation signal, and a control signal output unit that outputs a control signal in response to the target control amount, wherein the controller has: a current behavior prediction unit that predicts the behavior of the controlled element at a current performance of the hydraulic drive system in response to the operation signal input from the operating device; a reference behavior prediction unit that predicts the behavior of the controlled element at a reference performance of the hydraulic drive system in response to the operation signal input from the operating device; and a control signal correction unit that corrects the control signal so that the prediction result of the current behavior prediction unit approaches the prediction result of the reference behavior prediction unit, and the control signal output unit outputs the corrected control signal corrected by the control signal correction unit to the hydraulic drive system. [Effects of the Invention]

[0009] According to the present invention, in a hydraulic drive system, the influence of the accumulated errors contained in the controlled element on the static and dynamic characteristics of the controlled element in response to an operation input can be suppressed, thereby making it possible to improve the control robustness of the work machine. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a side view of a hydraulic excavator according to an embodiment of the present invention; [Figure 2A] 1 is a hydraulic circuit diagram (1 / 2) of a hydraulic drive system according to a first embodiment of the present invention; [Figure 2B] Hydraulic circuit diagram (2 / 2) of the hydraulic drive system in the first embodiment of the present invention [Figure 3] FIG. 1 is a diagram showing the operating characteristics of a solenoid valve according to a first embodiment of the present invention. [Figure 4]Functional block diagram of a controller according to a first embodiment of the present invention. [Figure 5] FIG. 1 is a flowchart showing the calculation process related to the learning process of the controller in the first embodiment of the present invention. [Figure 6] FIG. 1 is a flow chart showing the calculation process related to the control of the hydraulic drive system by the controller in the first embodiment of the present invention. [Figure 7] FIG. 10 is a diagram showing the behavior of the solenoid valve command pressure in the first embodiment of the present invention. [Figure 8] Functional block diagram of a controller according to a second embodiment of the present invention. [Figure 9] FIG. 10 is a flowchart showing the calculation process related to the learning process of the controller in the second embodiment of the present invention. [Figure 10] FIG. 10 is a flow chart showing the calculation process related to the control of the hydraulic drive system by the controller in the second embodiment of the present invention. [Figure 11] FIG. 10 is a diagram showing the behavior of the actuator speed in the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a hydraulic excavator will be described as an example of a work machine, but the present invention can also be applied to other work machines such as wheel loaders, dump trucks, hydraulic cranes, etc. In addition, in each drawing, equivalent members are given the same reference numerals, and duplicate explanations will be omitted as appropriate.

[0012] Figure 1 is a side view of a hydraulic excavator according to an embodiment of the present invention. The hydraulic excavator 901 includes a traveling body 201, a revolving body 202 (vehicle body) that is rotatably disposed on the traveling body 201 and constitutes a vehicle body, and a working device 203 that is attached to the revolving body 202 so as to be rotatable in the vertical direction and that performs work such as excavating earth and sand. The traveling body 201 is driven by a traveling motor (not shown) that is a hydraulic actuator. The revolving body 202 is driven by a swing motor 211 that is a hydraulic actuator.

[0013] The working device 203 includes a boom 204 attached to the revolving unit 202 so as to be rotatable in the vertical direction, an arm 205 attached to the tip of the boom 204 so as to be rotatable in the vertical direction, a bucket 206 attached to the tip of the arm 205 so as to be rotatable in the vertical direction, a boom cylinder 204a which is a hydraulic actuator that drives the boom 204, an arm cylinder 205a which is a hydraulic actuator that drives the arm 205, and a bucket cylinder 206a which is a hydraulic actuator that drives the bucket 206. The working device 203 is equipped with motion detection devices 212 to 214 that detect the motions (attitude, speed, etc.) of the boom 204, the arm 205, and the bucket 206. The revolving unit 202 is equipped with motion detection devices 215 and 216 that detect the attitude and rotation speed of the revolving unit 202. A variety of sensors can be used as the motion detection devices 212 to 216, such as an inertial measurement unit (IMU), an inclination sensor, a rotation angle sensor, a stroke sensor, and an acceleration sensor.

[0014] An operator's cab 207 is provided at a front position on the rotating body 202, and a counterweight 209 is provided at a rear position to ensure weight balance with the work device 203. A machinery room 208 is provided between the operator's cab 207 and the counterweight 209. The machinery room 208 houses an engine (not shown), hydraulic pumps 1 to 3 (shown in FIG. 2A), a swing motor 211, a control valve 210, and the like. The control valve 210 controls the flow of hydraulic oil from the hydraulic pumps 1 to 3 to the hydraulic actuators 204a, 205a, 206a, and 211 (including hydraulic actuators not shown).

[0015] The hydraulic excavator 901 in this embodiment is equipped with a hydraulic drive system which will be described in each of the following examples. [Example]

[0016] 2A and 2B are hydraulic circuit diagrams of a hydraulic drive system according to a first embodiment of the present invention. The hydraulic drive system 902 includes three main hydraulic pumps (for example, a first hydraulic pump 1, a second hydraulic pump 2, and a third hydraulic pump 3, which are variable displacement hydraulic pumps), a pilot pump 111, and a hydraulic oil tank 4 that supplies oil to the hydraulic pumps 1 to 3 and the pilot pump 111. The hydraulic pumps 1 to 3 and the pilot pump 111 are driven by an engine (not shown).

[0017] The tilt angle of the first hydraulic pump 1 is controlled by a regulator attached to the first hydraulic pump 1. The regulator of the first hydraulic pump 1 has a flow control command pressure port 1a and is driven by a command pressure acting on the flow control command pressure port 1a. The tilt angle of the second hydraulic pump 2 is controlled by a regulator attached to the second hydraulic pump 2. The regulator of the second hydraulic pump 2 has a flow control command pressure port 2a and is driven by a command pressure acting on the flow control command pressure port 2a. The tilt angle of the third hydraulic pump 3 is controlled by a regulator attached to the third hydraulic pump 3. The regulator of the third hydraulic pump 3 has a flow control command pressure port 3a and is driven by a command pressure acting on the flow control command pressure port 3a.

[0018] The discharge line 41 of the first hydraulic pump 1 is connected to the hydraulic oil tank 4 via a center bypass line 42. Arranged in the center bypass line 42, in this order from upstream, are a right travel directional control valve 6, a bucket directional control valve 7, a second arm directional control valve 8, and a first boom directional control valve 9. The right travel directional control valve 6 controls the flow of pressure oil supplied from the first hydraulic pump 1 to the right travel motor (not shown) of a pair of travel motors that drive the travelling body 201. The bucket directional control valve 7 controls the flow of pressure oil supplied from the first hydraulic pump 1 to the bucket cylinder 206a. The second arm directional control valve 8 controls the flow of pressure oil supplied from the first hydraulic pump 1 to the arm cylinder 205a. The first boom directional control valve 9 controls the flow of pressure oil supplied from the first hydraulic pump 1 to the boom cylinder 204a.

[0019] The supply ports of bucket directional control valve 7, second arm directional control valve 8, and first boom directional control valve 9 are connected in parallel to parallel line 43, which branches off from a portion of center bypass line 42 that connects right travel directional control valve 6 and bucket directional control valve 7, via oil passages 44 and 45, oil passages 46 and 47, and oil passages 48 and 49, respectively. A bleed-off valve 34 is disposed at the most downstream position of center bypass line 42, controlling the flow of pressurized oil discharged from center bypass line 42 to hydraulic oil tank 4. Discharge line 41 is connected to hydraulic oil tank 4 via oil passage 50. A relief valve 31 is provided in oil passage 50 to protect the circuit from excessive pressure buildup.

[0020] The discharge line 51 of the second hydraulic pump 2 is connected to the hydraulic oil tank 4 via a center bypass line 52. Arranged in the center bypass line 52, in this order from upstream, are a second boom directional control valve 10, a first arm directional control valve 11, a first attachment directional control valve 12, and a left travel directional control valve 13. The second boom directional control valve 10 controls the flow of pressure oil supplied from the second hydraulic pump 2 to the boom cylinder 204a. The first arm directional control valve 11 controls the flow of pressure oil supplied from the second hydraulic pump 2 to the arm cylinder 205a. The first attachment directional control valve 12 controls the flow of pressure oil supplied from the second hydraulic pump 2 to a first actuator (not shown) that drives a first special attachment, such as a small breaker, that is provided in place of the bucket 206. The left travel directional control valve 13 controls the flow of pressure oil supplied from the second hydraulic pump 2 to a left travel motor (not shown) of a pair of travel motors that drive the travel body 201.

[0021] The supply ports of the second boom directional control valve 10, the first arm directional control valve 11, the first attachment directional control valve 12, and the left travel directional control valve 13 are connected in parallel to a parallel line 53 branching off from a discharge line 51 via oil passages 54 and 55, oil passages 56 and 57, oil passages 58 and 59, and oil passage 60, respectively. A bleed-off valve 35 is disposed at the most downstream end of the center bypass line 52, controlling the flow of pressurized oil discharged from the center bypass line 52 to the hydraulic oil tank 4. The parallel line 53 and the discharge line 41 of the first hydraulic pump are connected via an oil passage 69, and a junction valve 37 is disposed in the oil passage 69. A check valve 38 is disposed in the oil passage 69 downstream of the junction valve 37, to prevent backflow from the parallel line 53 to the discharge line 41. A check valve 39 is disposed at the most downstream end of the parallel line 53, to prevent backflow from the discharge line 41 to the parallel line 53. The parallel line 53 is connected to the hydraulic oil tank 4 via an oil passage 61. The oil passage 61 is provided with a relief valve 32 for protecting the circuit from an excessive pressure rise.

[0022] The discharge line 62 of the third hydraulic pump 3 is connected to the hydraulic oil tank 4 via a center bypass line 63. Arranged in the center bypass line 63, in this order from upstream, are a swing directional control valve 14, a third boom directional control valve 15, and a second attachment directional control valve 16. The swing directional control valve 14 controls the flow of pressure oil supplied from the third hydraulic pump 3 to the swing motor 211. The third boom directional control valve 15 controls the flow of pressure oil supplied from the third hydraulic pump 3 to the boom cylinder 204a. The second attachment directional control valve 16 controls the flow of pressure oil supplied from the third hydraulic pump 3 to the second actuator when a second special attachment equipped with a second actuator is attached in addition to the first special attachment, or when a second special attachment equipped with two actuators, a first actuator and a second actuator, is attached instead of the first special attachment.

[0023] The supply ports of the swing directional control valve 14, the third boom directional control valve 15, and the second attachment directional control valve 16 are connected in parallel to a parallel line 64 branching off from a discharge line 62 via oil passages 65 and 66, oil passages 67 and 68, and oil passages 69 and 70, respectively. At the most downstream position of the center bypass line 63, a bleed-off valve 36 is disposed to control the flow of pressurized oil discharged from the center bypass line 63 to the hydraulic oil tank 4. The parallel line 64 is connected to the hydraulic oil tank 4 via an oil passage 71. A relief valve 33 is provided in the oil passage 71 to protect the circuit from excessive pressure buildup.

[0024] Oil passages 44, 45 connected to the supply port of bucket operation directional control valve 7, oil passages 46, 47 connected to the supply port of second arm operation directional control valve 8, and oil passages 48, 49 connected to the supply port of first boom operation directional control valve 9 are respectively provided with flow control valves 21 to 23 that control the flow rate of pressure oil supplied from first hydraulic pump 1 to each directional control valve during combined operation. Oil passages 54, 55 connected to the supply port of second boom operation directional control valve 10, oil passages 56, 57 connected to the supply port of first arm operation directional control valve 11, and oil passages 58, 59 connected to the supply port of first attachment operation directional control valve 12 are respectively provided with flow control valves 24 to 26 that control the flow rate of pressure oil supplied from second hydraulic pump 2 to each directional control valve during combined operation. Oil passages 65, 66 connected to the supply port of the swing directional control valve 14, oil passages 67, 68 connected to the supply port of the third boom directional control valve 15, and oil passages 69, 70 connected to the supply port of the second attachment directional control valve 16 are each provided with flow control valves 27 to 29 that control the flow rate of pressurized oil supplied from the third hydraulic pump 3 to each directional control valve during combined operation.

[0025] The flow control valve 25, which controls the flow rate of pressurized oil supplied to the first arm directional control valve 11, includes a seat-type main valve 25a that forms an auxiliary variable throttle, a control variable throttle 25b provided in the main valve 25a and whose opening area varies depending on the amount of movement of the main valve 25a, and a pilot variable throttle 25i. The housing containing the main valve 25a includes a first pressure chamber 25c formed at the connection between the main valve 25a and oil passage 56, a second pressure chamber 25d formed at the connection between the main valve 25a and oil passage 57, and a third pressure chamber 25e that communicates with the first pressure chamber 25c via an oil passage 25g provided inside the main valve 25a and the control variable throttle 25b. A check valve 25f for preventing backflow is provided in the oil passage 25g. The pilot variable throttle 25i is located in an oil passage 25h connecting the third pressure chamber 25e to the oil passage 57. Although some parts are omitted for ease of explanation, the flow control valves 21 to 29 and peripheral devices, piping and wiring all have the same configuration.

[0026] The hydraulic oil tank 4 is provided with a temperature sensor 91 that detects the temperature of the hydraulic oil in the hydraulic oil tank 4. The discharge line 41 of the first hydraulic pump 1 is provided with a pressure sensor 84 that detects the discharge pressure of the first hydraulic pump 1. The discharge line 51 is provided with a pressure sensor 85 that detects the discharge pressure of the second hydraulic pump 2. The discharge line 62 of the third hydraulic pump 3 is provided with a pressure sensor 86 that detects the discharge pressure of the third hydraulic pump 3.

[0027] A pressure sensor 87a detecting the actuator pressure on the bottom side of the boom cylinder 204a is provided in the actuator line 72a connecting the bottom side of the boom cylinder 204a and the boom direction control valves 9, 10, 15. A pressure sensor 87b detecting the actuator pressure on the rod side of the boom cylinder 204a is provided in the actuator line 72b connecting the rod side of the boom cylinder 204a and the boom direction control valves 9, 10, 15. A pressure sensor 88a detecting the actuator pressure on the bottom side of the arm cylinder 205a is provided in the actuator line 73a connecting the bottom side of the arm cylinder 205a and the arm direction control valves 8, 11. A pressure sensor 88b detecting the actuator pressure on the rod side of the arm cylinder 205a is provided in the actuator line 73b connecting the rod side of the arm cylinder 205a and the arm direction control valves 8, 11. A pressure sensor 89a that detects the actuator pressure on the bottom side of the bucket cylinder 206a is provided in actuator line 74a that connects the bottom side of the bucket cylinder 206a and the bucket direction control valve 7. A pressure sensor 89b that detects the actuator pressure on the rod side of the bucket cylinder 206a is provided in actuator line 74b that connects the rod side of the bucket cylinder 206a and the bucket direction control valve 7. Pressure sensors 90a and 90b that detect the actuator pressure of the swing motor 211 are provided in actuator lines 75a and 75b that connect the swing motor 211 and the swing direction control valve 14. To simplify the explanation, pressure sensors that detect the actuator pressure of the actuators that drive the left traveling motor, right traveling motor, and attachment (not shown) are not shown in the illustration.

[0028] 2B, the discharge port of pilot pump 111 is connected to hydraulic oil tank 4 via pilot relief valve 112 for generating pilot primary pressure, and is also connected to one input port of solenoid valves 113a to 113e built into solenoid valve unit 113 via pilot line 121. The other input ports of solenoid valves 113a to 113e are connected to hydraulic oil tank 4 via tank line 122. Each of solenoid valves 113a to 113e reduces the pilot primary pressure in response to a control signal from controller 114, which will be described later, and outputs the reduced pressure as a command pressure.

[0029] The output port of solenoid valve 113a is connected to the flow control command pressure port 2a of the regulator of second hydraulic pump 2 via a pilot line 123. The output ports of solenoid valves 113b and 113c are connected to the command pressure ports 11a and 11b of the first arm directional control valve 11 via pilot lines 124 and 125. The output port of solenoid valve 113d is connected to the command pressure port 25j of the flow control valve 25 via a pilot line 126. The output port of solenoid valve 113e is connected to the command pressure port 35a of the bleed-off valve 35 via a pilot line 127. For ease of explanation, solenoid valves for hydraulic pumps 1 and 3, directional control valves 6 to 10, 12 to 16, flow control valves 21 to 24, 26 to 29, bleed-off valves 34 and 36, and junction valve 37 are not shown in the figure.

[0030] The pilot line 121 is provided with a temperature sensor 92 that detects the temperature of the hydraulic oil flowing through the pilot line 121. The pilot line 123 is provided with a pressure sensor 133 that detects the flow rate control command pressure of the second hydraulic pump 2 output from the solenoid valve 113a. The pilot lines 124 and 125 are provided with pressure sensors 134 and 135 that detect the command pressure of the first arm directional control valve 11 output from the solenoid valves 113b and 113c. The pilot line 126 is provided with a pressure sensor 136 that detects the command pressure of the flow rate control valve 25 output from the solenoid valve 113d. The pilot line 127 is provided with a pressure sensor 137 that detects the command pressure of the bleed-off valve 35 output from the solenoid valve 113e. Similar pressure sensors are also provided in pilot lines connected to output ports of solenoid valves (not shown).

[0031] Current sensors 143-147 are provided on each signal line connecting the controller 114 and the solenoid valves 113a-113e as electrical signal detection devices that detect each control signal (control current) output from the controller 114 to the solenoid valves 113a-113e. Current sensors are also provided on signal lines connecting solenoid valves (not shown) to the controller 114. If the electrical control signals output from the controller 114 to the solenoid valves 113a-113e are control voltages, voltage sensors are provided instead of the current sensors 143-147.

[0032] The hydraulic drive system 902 includes a boom operation lever 115a (operation device) that can switch between the first boom direction control valve 9, the second boom direction control valve 10, and the third boom direction control valve 15, and an arm operation lever 115b (operation device) that can switch between the first arm direction control valve 11 and the second arm direction control valve 8. To simplify the explanation, the right travel operation lever that switches between the right travel direction control valve 6, the bucket operation lever that switches between the bucket directional control valve 7, the first attachment operation lever that switches between the first attachment directional control valve 12, the left travel operation lever that switches between the left travel direction control valve 13, the swing operation lever that switches between the swing directional control valve 14, and the second attachment operation lever that switches between the second attachment directional control valve 16 are not shown in the figure.

[0033] The hydraulic drive system 902 includes a controller 114 that controls the solenoid valves 113a-113e, a target plane setting device 116 that sets a target plane when the bucket 206 is excavated, and an additional learning instruction device 117 that instructs the controller 114 to perform additional learning (described later). The controller 114 outputs control signals for the solenoid valves 113a-113e in response to operation signals from the operation devices 115a and 115b, the target plane setting value from the target plane setting device 116, the additional learning instruction from the additional learning instruction device 117, output values ​​of the pressure sensors 84-86, 87a, 87b, 88a, 88b, 89a, 89b, 90a, 90b, 133-137, output values ​​of the temperature sensors 91 and 92, output values ​​of the current sensors 143-147, and posture data from the motion detection devices 212-216.

[0034] FIG. 3 is a diagram showing the operating characteristics of the solenoid valves 113a to 113e. The solenoid valves 113a to 113e reduce the pilot primary pressure in response to a solenoid valve control signal from the controller 114 and output the result as a solenoid valve command pressure. The solenoid valve control signal is determined in response to a solenoid valve target command pressure. At this time, an error occurs between the solenoid valve target command pressure and the actually generated solenoid valve command pressure. This error does not depend on the passage of time, and is therefore an error in the static characteristics of the solenoid valves 113a to 113e. Furthermore, when the solenoid valve target command pressure is changed, a delay occurs in the change in the actually generated solenoid valve command pressure relative to that change, and this delay results in an error. This error depends on the passage of time, and is therefore an error in the dynamic characteristics of the solenoid valves 113a to 113e. These errors occur due to various factors, such as individual variations between the solenoid valves 113a to 113e, changes in the operating environment, and deterioration of the solenoid valves 113a to 113e, or a combination of these factors.

[0035] 4 is a functional block diagram of a controller 114 according to the first embodiment. The controller 114 includes an actuator target speed calculation unit 114a, an actuator target flow rate calculation unit 114b, a solenoid valve target command pressure calculation unit 114c, a solenoid valve target command pressure correction unit 114d, a solenoid valve control signal output unit 114e, a target operation detection unit 114f, an operating environment detection unit 114g, an operation state detection unit 114h, a learning data storage unit 114i, a deterioration state detection unit 114j, a learning unit 114k, a current behavior prediction unit 114l, a reference behavior prediction unit 114m, and a prediction accuracy evaluation unit 114n. The controller 114 includes a calculation unit such as a CPU, a storage unit such as a ROM and RAM, an input / output interface for inputting and outputting signals to and from external devices, and the functions of each unit are realized by loading a program stored in the ROM onto the RAM and executing it.

[0036] The actuator target velocity calculation unit 114a calculates the actuator target velocity required for the operation of the working device 203 based on the operation signals from the operation devices 115a and 115b, the posture data from the motion detection devices 212 to 216, and the target plane setting value from the target plane setting device 116. The actuator target flow rate calculation unit 114b calculates the actuator target flow rate based on the actuator target velocity from the actuator target velocity calculation unit 114a.

[0037] The solenoid valve target command pressure calculation unit 114c calculates the solenoid valve target command pressure based on the actuator target flow rate from the actuator target flow rate calculation unit 114b. The solenoid valve target command pressure correction unit 114d corrects the solenoid valve target command pressure from the solenoid valve target command pressure calculation unit 114c so that the prediction result from the current behavior prediction unit 114l approaches the prediction result from the reference behavior prediction unit 114m. However, if an additional learning instruction is input from the additional learning instruction device 117, the correction process for the solenoid valve target command pressure is temporarily stopped. The solenoid valve control signal output unit 114e generates a solenoid valve control signal based on the solenoid valve target command pressure from the solenoid valve target command pressure correction unit 114d and outputs it to the solenoid valves 113a to 113e.

[0038] A target operation detection unit 114f generates target operation data for the hydraulic drive system 902 based on the solenoid valve target command pressure from the solenoid valve target command pressure calculation unit 114c. An operating environment detection unit 114g generates operating environment data for the hydraulic drive system 902 based on output values ​​from temperature sensors 91 and 92. In this embodiment, the operating environment data is generated based on the temperature of the hydraulic oil, but the operating environment data may also be generated based on the temperature of the cooling water circulating within the hydraulic drive system 902 or the outside air temperature. An operating state detection unit 114h generates operating state data for the hydraulic drive system 902 based on output values ​​from the current sensors 143 to 147 and the pressure sensors 84 to 86, 87a, 87b, 88a, 88b, 89a, 89b, 90a, 90b, and 133 to 137. The target operation detection unit 114f, the operating environment detection unit 114g, the operating state detection unit 114h, and the deterioration state detection unit 114j in this embodiment constitute an operating state detection unit that detects the operating state of the hydraulic drive system 902.

[0039] The learning data storage unit 114i receives the target operation data from the target operation detection unit 114f, the operating environment data from the operating environment detection unit 114g, and the operating state data from the operating state detection unit 114h and stores them as operating state data (learned data). The degradation state detection unit 114j performs data analysis and determines the solenoid valve degradation state based on the operating state data stored in the learning data storage unit 114i, and generates degradation state data. The learning data storage unit 114i also stores the degradation state data from the degradation state detection unit 114j as operating state data (learned data).

[0040] The learning unit 114k performs a learning process based on the learning data in the learning data storage unit 114i in accordance with the evaluation result (described later) from the prediction accuracy evaluation unit 114n, and generates a prediction model that predicts the behavior of the solenoid valves 113a to 113e when a solenoid valve control signal corresponding to the solenoid valve target command pressure is output from the solenoid valve target command pressure calculation unit 114c in the current hydraulic drive system 902.

[0041] The current behavior prediction unit 114l predicts the behavior of the solenoid valve command pressure relative to the solenoid valve target command pressure at the current performance, based on the solenoid valve target command pressure from the solenoid valve target command pressure calculation unit 114c and the operating state data stored in the learning data storage unit 114i, using the prediction model generated by the learning unit 114k. The current performance here refers to the performance of the hydraulic drive system 902 at the current time. The reference behavior prediction unit 114m predicts the behavior of the solenoid valve command pressure relative to the solenoid valve target command pressure at the reference performance, based on the solenoid valve target command pressure from the solenoid valve target command pressure calculation unit 114c and the operating state data stored in the learning data storage unit 114i. The reference performance here refers to the performance of the hydraulic drive system 902 measured when the relationship between the solenoid valve target command pressure from the solenoid valve target command pressure calculation unit 114c and the solenoid valve command pressures actually generated by the solenoid valves 113a to 113e is calibrated at a design specification of the hydraulic drive system 902 (performance that must be met as determined at the design stage) or at a reference point in time (for example, the stage at which the hydraulic excavator 901 is shipped after assembly). When an additional learning instruction is input from the additional learning instruction device 117, for example, the prediction accuracy evaluation unit 114n compares the solenoid valve predicted command pressure from the current behavior prediction unit 114l with the solenoid valve command pressures measured by the pressure sensors 133 to 137 to evaluate the prediction accuracy of the current behavior prediction unit 114l.

[0042] FIG. 5 is a flowchart showing the calculation process of the controller 114 related to the learning process.

[0043] The controller 114 first determines whether it is a specific timing (for example, immediately after the hydraulic excavator 901 starts operating) or whether a certain time has elapsed (step S101). If the determination result in step S101 is NO, the flow ends.

[0044] In parallel with step S101, the controller 114 determines whether or not there is an additional learning instruction from the additional learning instruction device 117 (step S102). If the determination result in step S102 is NO, the flow ends.

[0045] If the determination result in step S101 or step S102 is YES, the controller 114 outputs a solenoid valve control signal without correcting the solenoid valve target command pressure in the solenoid valve target command pressure correcting section 114d (step S103).

[0046] Following step S103, the controller 114 causes the prediction accuracy evaluation unit 114n to calculate the degree of deviation (prediction error) between the solenoid valve predicted command pressure from the current behavior prediction unit 114l and the solenoid valve command pressure measured by the pressure sensors 133 to 137 (step S104), and determines whether the prediction error exceeds a preset allowable error (i.e., whether additional learning is necessary) (step S105). If the determination result in step S105 is NO, the flow ends.

[0047] If the determination result in step S105 is YES, the controller 114 generates target operation data in the target operation detection unit 114f based on the solenoid valve target command pressure from the solenoid valve target command pressure calculation unit 114c, generates operating environment data in the operating environment detection unit 114g based on the output values ​​of the temperature sensors 91 and 92, generates operating state data in the operating state detection unit 114h based on the output values ​​of the current sensors 143 to 147 and the pressure sensors 84 to 86, 87a, 87b, 88a, 88b, 89a, 89b, 90a, 90b, 133 to 137, and generates deterioration state data in the deterioration state detection unit 114j based on the target operation data, operating environment data, and operating state data stored in the learning data memory unit 114i (step S106).

[0048] Following step S106, the controller 114 stores the target operation data from the target operation detection unit 114f, the operation environment data from the operation environment detection unit 114g, the operation state data from the operation state detection unit 114h, and the degradation state data from the degradation state detection unit 114j in the learning data memory unit 114i (step S107).

[0049] Following step S107, the controller 114 causes the learning unit 114k to perform learning processing based on the learning data in the learning data storage unit 114i, generate a prediction model that predicts the behavior of the solenoid valve command pressure (step S108), and then ends the flow.

[0050] FIG. 6 is a flowchart showing the calculation process of the controller 114 related to the control of the hydraulic drive system 902.

[0051] The controller 114 first determines whether or not there is an input (operation input) from the operation devices 115a and 115b (step S201). If the determination result in step S201 is NO, the flow ends.

[0052] If the determination result in step S201 is YES, the controller 114 causes the actuator target speed calculation unit 114a to calculate the actuator target speed based on the operation signal, the attitude data, the target surface setting value, etc. (step S202).

[0053] Following step S202, the controller 114 calculates the actuator target flow rate based on the actuator target speed in the actuator target flow rate calculation unit 114b (step S203).

[0054] Following step S203, the controller 114 calculates a target command pressure for the solenoid valve based on the target flow rate of the actuator in the solenoid valve target command pressure calculation unit 114c (step S204).

[0055] Following step S204, the controller 114 uses the prediction model generated by the learning unit 114k to calculate, in the current behavior prediction unit 114l, a predicted command pressure of the solenoid valve at the current performance based on the solenoid valve target command pressure and the operating state data stored in the learning data storage unit 114i (step S205).

[0056] In parallel with step S205, the controller 114 calculates a predicted command pressure for the solenoid valve at the reference performance in the reference behavior prediction unit 114m based on the target command pressure for the solenoid valve and the operating state data stored in the learning data storage unit 114i (step S206).

[0057] Following steps S205 and S206, the controller 114 corrects the solenoid valve target command pressure in the solenoid valve target command pressure correction unit 114d so that the deviation between the solenoid valve predicted command pressure from the reference behavior prediction unit 114m and the solenoid valve predicted command pressure from the current behavior prediction unit 114l becomes smaller (step S207).

[0058] Following step S207, the controller 114 causes the solenoid valve control signal output unit 114e to output a solenoid valve control signal according to the corrected solenoid valve target command pressure from the solenoid valve target command pressure correcting unit 114d (step S208), and ends this flow.

[0059] Here, the current behavior prediction unit 114l and the reference behavior prediction unit 114m predict the behavior of the solenoid valve after a preset future time has elapsed, starting from the time when the solenoid valve control signal is output. The future time is desirably set to a value equivalent to the dead time from when the controller 114 outputs the solenoid valve control signal until the solenoid valve actually starts to generate the command pressure.

[0060] (operation) The operation of the hydraulic drive system 902 in the first embodiment will be described. First, an operation signal corresponding to an operation by an operator is input from the operation devices 115a, 115b to the controller 114. The controller 114 calculates a solenoid valve target command pressure based on the input operation signal and the like, corrects the solenoid valve target command pressure so that the predicted solenoid valve command pressure at the current performance approaches the predicted solenoid valve command pressure at the reference performance, and outputs a solenoid valve control signal corresponding to the corrected solenoid valve target command pressure.

[0061] 7 is a diagram showing the behavior of the solenoid valve command pressure. In the hydraulic drive system 902, when a solenoid valve control signal corresponding to the uncorrected solenoid valve target command pressure is output, the actual command pressure (without correction) significantly overshoots the target command pressure immediately after rising, and the behavior of the actual command pressure thereafter becomes unstable. In response to this, by correcting the target command pressure so that the predicted command pressure for the current performance approaches the predicted command pressure for the reference performance, the behavior of the actual command pressure (with correction) can be made closer to the behavior for the reference performance. As a result, even if the current performance of the hydraulic drive system 902 deteriorates, it is possible to suppress the effect of the performance deterioration of the hydraulic drive system 902 on the static characteristics and dynamic characteristics of the solenoid valves 113a to 113e in response to operation inputs.

[0062] Furthermore, while the hydraulic excavator 901 is performing work, target operation data, operating environment data, operating state data, and deterioration state data are accumulated in the learning data storage unit 114i. The controller 114 drives the solenoid valve without correcting the solenoid valve target command pressure at a specific timing, every time a fixed time elapses, or when an additional learning command is input, and compares the solenoid valve command pressure measured at that time with the predicted solenoid valve command pressure from the current behavior prediction unit 114l to evaluate the prediction accuracy of the current behavior prediction unit 114l. If it is determined that the prediction accuracy has decreased, the controller 114 performs learning processing in the learning unit 114k based on the learning data accumulated in the learning data storage unit 114i, and updates the prediction model. This makes it possible to maintain the prediction accuracy of the current behavior prediction unit 114l.

[0063] (summary) In the first embodiment, a hydraulic excavator is provided with a vehicle body 202, a working device 203 attached to the vehicle body 202, hydraulic actuators 204a, 205a, 206a that drive the working device 203, a hydraulic drive system 902 that drives the hydraulic actuators 204a, 205a, 206a, operation devices 115a, 115b that instruct the operation of the hydraulic actuators 204a, 205a, 206a, and a controller 114 that controls the hydraulic drive system 902 in accordance with operation signals input from the operation devices 115a, 115b, and the controller 114 has a solenoid valve target command pressure calculation unit 114c (target control amount calculation unit) that calculates target command pressures (target control amounts) of solenoid valves 113a to 113e (control target elements) based on the operation signals, and a solenoid valve control signal output unit 114e (control signal output unit) that outputs a control signal in accordance with the target command pressure. In a hydraulic drive system 901 (work machine), a controller 114 includes a current behavior prediction unit 114l that predicts the behavior of the solenoid valves 113a to 113e with respect to the target command pressure at the current performance of the hydraulic drive system 902, in accordance with operation signals input from operation devices 115a and 115b; a reference behavior prediction unit 114m that predicts the behavior of the solenoid valves 113a to 113e with respect to the target command pressure at the reference performance of the hydraulic drive system 902, in accordance with operation signals input from the operation devices 115a and 115b; and a solenoid valve target command pressure correction unit 114d (control signal correction unit) that corrects the control signal so that the prediction result of the current behavior prediction unit 114l approaches the prediction result of the reference behavior prediction unit 114m. The solenoid valve control signal output unit 114e outputs the control signal corrected by the solenoid valve target command pressure correction unit 114d to the hydraulic drive system 902.

[0064] According to the first embodiment configured as described above, even if the current performance of the hydraulic drive system 902 is reduced due to individual variations in the components constituting the hydraulic drive system 902, disturbances in the work environment, performance degradation, etc., it is possible to make the behavior of the solenoid valves 113a to 113e closer to the behavior at the reference performance of the hydraulic drive system 902. As a result, the effect of performance degradation of the hydraulic drive system 902 on the static characteristics and dynamic characteristics of the solenoid valves 113a to 113e in response to operation inputs is reduced, making it possible to improve the control robustness of the hydraulic excavator 901.

[0065] The reference performance of the hydraulic drive system 902 is the performance of the hydraulic drive system 902 measured when the design specifications of the hydraulic drive system 902 or the relationship between the target control amount and the behavior of the solenoid valves 113a to 113e (control target elements) is calibrated. This makes it possible to unify the reference performance of the hydraulic drive system 902.

[0066] Furthermore, the current behavior prediction unit 114l and the reference behavior prediction unit 114m each predict the behavior of the solenoid valves 113a to 113e after a preset future time has elapsed, starting from the time when the control signal is output, and the future time is set based on the dead time of the solenoid valves 113a to 113e with respect to the control signal. This makes it possible to correct the solenoid valve target command pressure without delay.

[0067] The hydraulic excavator 901 also includes operating state detection units 114f-114h, 114j that detect the operating state of the hydraulic drive system 902, a reference behavior prediction unit 114m that predicts the behavior of the solenoid valves 113a-113e at the reference performance based on the target command pressure and detection values ​​from the operating state detection units 114f-114h, 114j, and a current behavior prediction unit 114l that predicts the behavior of the solenoid valves 113a-113e at the current performance based on the target command pressure and detection values ​​from the operating state detection units 114f-114h, 114j. This makes it possible to predict with high accuracy the behavior of the solenoid valves 113a-113e at the reference performance and the current performance.

[0068] Furthermore, the operating state detection units 114f to 114h, 114j have at least one of an operating environment detection unit 114g that detects the operating environment of the hydraulic drive system 902 and an operating state detection unit 114h that detects the operating state of the hydraulic drive system 902. This makes it possible to improve the accuracy of predicting the behavior of the solenoid valves 113a to 113e at the reference performance and the current performance.

[0069] The controller 114 also has a learning data storage unit 114i that stores the detection results of the operating state detection units 114f-114h, 114j as learning data, and a learning unit 114k that performs learning processing based on the learning data and generates a prediction model that predicts the behavior of the solenoid valves 113a-113e, and a current behavior prediction unit 114l that uses the prediction model to predict the behavior of the solenoid valves 113a-113e at the current performance, thereby making it possible to improve the prediction accuracy of the behavior of the solenoid valves 113a-113e at the current performance.

[0070] The hydraulic excavator 901 also includes pressure sensors 133-137 (control variable measuring devices) that measure the command pressures (control variables) of the solenoid valves 113a-113e, and the controller 114 includes a prediction accuracy evaluation unit 114n that determines whether a prediction error, which is the degree of deviation between the measured value of the command pressure in a state in which the solenoid valve target command pressure correction unit 114d does not correct the control signal and the predicted command pressure (predicted control variable) calculated by the current behavior prediction unit 114l, exceeds a predetermined allowable error, and the learning unit 114k executes the learning process and updates the prediction model when the prediction accuracy evaluation unit 114n determines that the prediction error exceeds the allowable error. This makes it possible to maintain the prediction accuracy of the current behavior prediction unit 114l. [Example]

[0071] The second embodiment of the present invention will be described, focusing on the differences from the first embodiment. In the first embodiment, the solenoid valves 113a to 113e were the controlled elements for suppressing the effect of performance degradation of the hydraulic drive system 902 on the static and dynamic characteristics in response to an operation input, but in the second embodiment, the hydraulic actuators 204a, 205a, and 206a are the controlled elements.

[0072] 8 is a functional block diagram of a controller 114A in the second embodiment. The controller 114A has an actuator target speed corrector 114o instead of the solenoid valve target command pressure corrector 114d (shown in FIG. 4).

[0073] The learning unit 114k performs a learning process based on the learning data in the learning data storage unit 114i in accordance with the evaluation result (described later) from the prediction accuracy evaluation unit 114n, and generates a prediction model that predicts the behavior of the hydraulic actuators 204a, 205a, and 206a when a solenoid valve control signal corresponding to the actuator target speed is output from the actuator target speed calculation unit 114a in the current hydraulic drive system 902.

[0074] The current behavior prediction unit 114l uses the prediction model generated by the learning unit 114k to predict the behavior of the actuator speed under the current performance based on the solenoid valve target command pressure from the solenoid valve target command pressure calculation unit 114c and the operating state data stored in the learning data storage unit 114i. The reference behavior prediction unit 114m predicts the behavior of the actuator speed under the reference performance based on the solenoid valve target command pressure from the solenoid valve target command pressure calculation unit 114c and the operating state data stored in the learning data storage unit 114i. When an additional learning instruction is input from the additional learning instruction device 117, for example, the prediction accuracy evaluation unit 114n compares the predicted actuator speed from the current behavior prediction unit 114l with the actuator speed measured by the inertial measurement units 212 to 216 (control quantity measurement devices) to evaluate the prediction accuracy of the current behavior prediction unit 114l. Note that, although the present embodiment is configured to predict the behavior of the actuator speed, it may also be configured to predict the behavior of the actuator's angular velocity or rotation speed.

[0075] The actuator target speed correction unit 114o corrects the actuator target speed from the actuator target speed calculation unit 114a so that the prediction result from the current behavior prediction unit 114l approaches the prediction result from the reference behavior prediction unit 114m. However, if an additional learning instruction is input from the additional learning instruction device 117, the correction process for the actuator target speed is temporarily stopped.

[0076] The actuator target flow rate calculation unit 114b calculates the actuator target flow rate based on the actuator target speed from the actuator target speed correction unit 114o. The solenoid valve control signal output unit 114e generates a solenoid valve control signal based on the solenoid valve target command pressure from the solenoid valve target command pressure calculation unit 114c, and outputs it to the solenoid valves 113a to 113e.

[0077] FIG. 9 is a flowchart showing the calculation process related to the learning process of the controller 114A in the second embodiment.

[0078] The controller 114A first determines whether a specific timing (for example, immediately after the hydraulic excavator 901 starts operating) or whether a certain time has elapsed (step S101A). If the determination result in step S101A is NO, the flow ends.

[0079] In parallel with step S101A, controller 114A determines whether or not there is an additional learning instruction from additional learning instruction device 117 (step S102A). If the determination result in step S102A is NO, the flow ends.

[0080] If the determination result in step S101A or S102A is YES, the controller 114A outputs the solenoid valve control signal without correcting the actuator target speed in the actuator target speed correcting section 114o (step S103A).

[0081] Following step S103A, the controller 114A calculates the degree of deviation (prediction error) between the actuator predicted speed from the current behavior prediction unit 114l and the actuator speed calculated from the posture data in the prediction accuracy evaluation unit 114n (step S104A), and determines whether the prediction error exceeds a preset allowable error (step S105A). If the determination result in step S105A is NO, the flow ends.

[0082] If the determination result in step S105A is YES, the controller 114A generates target operation data in the target operation detection unit 114f based on the solenoid valve target command pressure from the solenoid valve target command pressure calculation unit 114c, generates operating environment data in the operating environment detection unit 114g based on the output values ​​of the temperature sensors 91 and 92, generates operating state data in the operating state detection unit 114h based on the output values ​​of the current sensors 143 to 147 and the pressure sensors 84 to 86, 87a, 87b, 88a, 88b, 89a, 89b, 90a, 90b, 133 to 137, and generates deterioration state data in the deterioration state detection unit 114j based on the target operation data, operating environment data, and operating state data stored in the learning data memory unit 114i (step S106A).

[0083] Following step S106A, the controller 114A stores the target operation data from the target operation detection unit 114f, the operation environment data from the operation environment detection unit 114g, the operation state data from the operation state detection unit 114h, and the degradation state data from the degradation state detection unit 114j in the learning data memory unit 114i (step S107A).

[0084] Following step S107A, the controller 114A causes the learning section 114k to perform a learning process based on the learning data in the learning data storage section 114i, and generates a prediction model that predicts the behavior of the actuator speed (step S108A), and then ends the flow.

[0085] FIG. 10 is a flowchart showing the calculation process related to the control of the hydraulic drive system 902 by the controller 114A in the second embodiment.

[0086] The controller 114A first determines whether or not there is an input (operation input) from the operation devices 115a and 115b (step S201A). If the determination result in step S201A is NO, the flow ends.

[0087] If the determination result in step S201A is YES, the controller 114A causes the actuator target speed calculation unit 114a to calculate the actuator target speed based on the operation signal, the attitude data, the target surface setting value, etc. (step S202A).

[0088] Following step S202A, the controller 114A uses the prediction model generated by the learning unit 114k in the current behavior prediction unit 114l to calculate the predicted actuator speed for the current performance based on the solenoid valve target command pressure and the operating state data stored in the learning data storage unit 114i (S203A).

[0089] In parallel with step S203A, the controller 114A calculates, in the reference behavior prediction unit 114m, a predicted actuator speed at the reference performance based on the actuator target speed and the operating state data stored in the learning data storage unit 114i (step S204A).

[0090] Following steps S203A and S204A, the controller 114A corrects the actuator target speed in the actuator target speed correction unit 114o so that the difference between the actuator predicted speed from the reference behavior prediction unit 114m and the actuator predicted speed from the current behavior prediction unit 114l becomes smaller (step S205A).

[0091] Following step S205A, the controller 114A causes the actuator target flow rate calculation section 114b to calculate the actuator target flow rate based on the corrected actuator target speed (step S206A).

[0092] Following step S206A, the controller 114A causes the solenoid valve target command pressure calculation unit 114c to calculate a solenoid valve target command pressure based on the actuator target flow rate (step S207A).

[0093] Following step S207A, the controller 114A causes the solenoid valve control signal output unit 114e to output a solenoid valve control signal corresponding to the solenoid valve target command pressure (step S208A), and ends this flow.

[0094] (operation) The operation of hydraulic drive system 902 in the second embodiment will be described. First, an operation signal corresponding to an operation by an operator is input from operation devices 115a, 115b to controller 114A. Controller 114A calculates an actuator target speed based on the input operation signal, etc., corrects the actuator target speed so that the predicted actuator speed for the reference performance approaches the predicted actuator speed for the current performance, and outputs a solenoid valve control signal corresponding to the corrected actuator target speed.

[0095] 11 is a diagram showing the behavior of the actuator speed. In the hydraulic drive system 902, when a solenoid valve control signal corresponding to the uncorrected actuator target speed is output, the actual speed (without correction) significantly overshoots the target speed immediately after rising, and the behavior of the actual speed thereafter becomes unstable. In response to this, by correcting the target speed so that the predicted speed for the current performance approaches the predicted speed for the reference performance, the behavior of the actual speed (with correction) can be made closer to the behavior for the reference performance. As a result, even if the current performance of the hydraulic drive system 902 deteriorates, it is possible to suppress the impact of the performance deterioration of the hydraulic drive system 902 on the static and dynamic characteristics of the hydraulic actuators 204a, 205a, and 206a in response to operation inputs.

[0096] Furthermore, the controller 114A drives the solenoid valve without correcting the actuator target speed at a specific timing, every time a certain time has elapsed, or when an additional learning command is input, and compares the actuator speed measured at that time with the actuator speed predicted by the current behavior prediction unit 114l to evaluate the prediction accuracy of the current behavior prediction unit 114l. If it is determined that the prediction accuracy has decreased, the controller 114A performs learning processing in the learning unit 114k based on the learning data accumulated in the learning data storage unit 114i, and updates the prediction model. This makes it possible to maintain the prediction accuracy of the current behavior prediction unit 114l.

[0097] (summary) In the second embodiment, a hydraulic excavator is provided which includes a vehicle body 202, a working device 203 attached to the vehicle body 202, hydraulic actuators 204a, 205a, 206a that drive the working device 203, a hydraulic drive system 902 that drives the hydraulic actuators 204a, 205a, 206a, operation devices 115a, 115b that instruct the operation of the hydraulic actuators 204a, 205a, 206a, and a controller 114A that controls the hydraulic drive system 902 in accordance with operation signals input from the operation devices 115a, 115b, and the controller 114A has an actuator target speed calculation unit 114a (target control amount calculation unit) that calculates target speeds (target control amounts) of the hydraulic actuators 204a, 205a, 206a (control target elements) of the hydraulic drive system 902 based on the operation signals, and a solenoid valve control signal output unit 114e (control signal output unit) that outputs control signals in accordance with the target speeds. In a hydraulic drive system 901 (work machine), a controller 114A has: a current behavior prediction unit 114l that predicts the behavior of the hydraulic actuators 204a, 205a, 206a at the target speed under the current performance of the hydraulic drive system 902, in response to operation signals input from the operation devices 115a, 115b; a reference behavior prediction unit 114m that predicts the behavior of the hydraulic actuators 204a, 205a, 206a at the target speed under the reference performance of the hydraulic drive system 902, in response to operation signals input from the operation devices 115a, 115b; and an actuator target speed correction unit 114o (control signal correction unit) that corrects the control signal so that the prediction result of the current behavior prediction unit 114l approaches the prediction result of the reference behavior prediction unit 114m. A solenoid valve control signal output unit 114e outputs the control signal corrected by the actuator target speed correction unit 114o to the hydraulic drive system 902.

[0098] According to the second embodiment configured as described above, even if the current performance of the hydraulic drive system 902 is reduced due to individual variations in the components constituting the hydraulic drive system 902, disturbances in the work environment, performance degradation, or the like, the behavior of the hydraulic actuators 204a, 205a, and 206a can be made closer to the behavior at the reference performance of the hydraulic drive system 902. As a result, the effect of performance degradation of the hydraulic drive system 902 on the static and dynamic characteristics of the hydraulic actuators 204a, 205a, and 206a in response to operation inputs is reduced, thereby improving the control robustness of the hydraulic excavator 901. In addition, the same effects as those of the first embodiment can be obtained, except that the controlled elements whose static and dynamic characteristics are reduced in the effect of performance degradation of the hydraulic drive system 902 are changed from the solenoid valves 113a to 113e to the hydraulic actuators 204a, 205a, and 206a.

[0099] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to add part of the configuration of one embodiment to the configuration of another embodiment, or to delete part of the configuration of one embodiment or replace it with part of another embodiment. [Explanation of symbols]

[0100] 1...first hydraulic pump, 1a...flow rate control command pressure port, 2...second hydraulic pump, 2a...flow rate control command pressure port, 3...third hydraulic pump, 3a...flow rate control command pressure port, 4...hydraulic oil tank, 6...right travel directional control valve, 7...bucket directional control valve, 8...second arm directional control valve, 9...first boom directional control valve, 10...second boom directional control valve, 11...first arm directional control valve, 11a, 11b...command pressure port, 12...Direction control valve for first attachment, 13...Direction control valve for left travel, 14...Direction control valve for swing, 15...Direction control valve for third boom, 15...Direction control valve for boom, 16...Direction control valve for second attachment, 21 to 25...Flow control valve, 25a...Main valve, 25c...First pressure chamber, 25d...Second pressure chamber, 25e...Third pressure chamber, 25f...Check valve, 25g, 25h...Oil passage, 25j...Command pressure port, 26 to 29...Flow rate Control valve, 31-33...Relief valve, 34, 35...Bleed-off valve, 35a...Command pressure port, 36...Bleed-off valve, 37...Confluence valve, 38, 39...Check valve, 41...Discharge line, 42...Center bypass line, 43...Parallel line, 44-50...Oil passage, 51...Discharge line, 52...Center bypass line, 53...Parallel line, 54-61...Oil passage, 62...Discharge line, 63...Center bypass line In, 64... parallel line, 65 to 71... oil passage, 72a, 72b, 73a, 73b, 74a, 74b, 75a, 75b... actuator line, 84 to 86, 87a, 87b, 88a, 88b, 89a, 89b, 90a, 90b... pressure sensor, 91, 92... temperature sensor, 111... pilot pump, 112... pilot relief valve, 113... solenoid valve unit, 113a to 113e... solenoid valve, 114,114A...controller, 114a...actuator target speed calculation unit (target control amount calculation unit), 114b...actuator target flow rate calculation unit, 114c...solenoid valve target command pressure calculation unit (target control amount calculation unit), 114d...solenoid valve target command pressure correction unit (control signal correction unit), 114e...solenoid valve control signal output unit (control signal output unit), 114f...target operation detection unit (operating state detection unit), 114g...operating environment detection unit (operating state detection unit), 114h...operating state detection unit (operating state detection unit), 114i...learning data storage unit, 114j...deterioration state detection unit (operating state detection unit), 114k...learning unit, 114l...current behavior prediction unit, 114m...reference behavior prediction unit, 114n...prediction accuracy evaluation unit, 114o...actuator target speed correction unit (control signal correction unit), 115a...boom operation lever (operating device), 115b...arm operation lever ( Operating device), 116... target plane setting device, 117... additional learning instruction device, 121... pilot line, 122... tank line, 123 to 127... pilot line, 133 to 137... pressure sensor (control quantity measuring device), 143 to 147... current sensor, 201... traveling body, 202... swing body (vehicle body), 203... working device, 204... boom, 204a... boom cylinder (hydraulic actuator), 205... arm, 205a... arm cylinder (hydraulic actuator), 206... bucket, 206a... bucket cylinder (hydraulic actuator), 207... operator's cab, 208... machine room, 209... counterweight, 210... control valve, 211... swing motor (hydraulic actuator), 212 to 216... operation detection device (control quantity measuring device), 901... hydraulic excavator (working machine), 902... hydraulic drive system.

Claims

1. The car body and a working device attached to the vehicle body; a hydraulic actuator that drives the working device; a hydraulic drive system that drives the hydraulic actuator; an operating device that instructs the operation of the hydraulic actuator; a controller that controls the hydraulic drive system in response to an operation signal input from the operation device, In a working machine, the controller has a target control amount calculation unit that calculates a target control amount of a controlled element of the hydraulic drive system based on the operation signal, and a control signal output unit that outputs a control signal according to the target control amount, The controller a current behavior prediction unit that predicts the behavior of the controlled element with respect to the target control amount in the current performance of the hydraulic drive system in response to an operation signal input from the operation device; a reference behavior prediction unit that predicts the behavior of the controlled element with respect to the target control amount in a reference performance of the hydraulic drive system in response to an operation signal input from the operation device; a control signal correcting unit that corrects the control signal so that a prediction result of the current behavior predicting unit approaches a prediction result of the reference behavior predicting unit, The control signal output unit outputs the control signal corrected by the control signal correcting unit to the hydraulic drive system. A work machine characterized by:

2. 2. The work machine according to claim 1, The reference performance is the design specification of the hydraulic drive system, or the performance of the hydraulic drive system measured when the relationship between the target control amount and the behavior of the controlled element is calibrated. A work machine characterized by:

3. 2. The work machine according to claim 1, the current behavior prediction unit and the reference behavior prediction unit each predict a behavior of the control target element after a predetermined future time has elapsed since the control signal was output, The future time is set based on the dead time of the controlled element with respect to the control signal. A work machine characterized by:

4. 2. The work machine according to claim 1, an operating state detection unit that detects an operating state of the hydraulic drive system; the reference behavior prediction unit predicts a behavior of the controlled element under the reference performance based on the target control amount and a detection value from the operation state detection unit; The current behavior prediction unit predicts the behavior of the controlled element in the current performance based on the target control amount and a detection value from the operation state detection unit. A work machine characterized by:

5. 5. The work machine according to claim 4, The operating condition detection unit has at least one of an operating environment detection unit that detects the operating environment of the hydraulic drive system and an operating condition detection unit that detects the operating condition of the hydraulic drive system. A work machine characterized by:

6. 5. The work machine according to claim 4, The controller a learning data storage unit that stores the detection result of the operating state detection unit as learning data; a learning unit that performs a learning process based on the learning data and generates a prediction model that predicts the behavior of the controlled element; The current behavior prediction unit predicts the behavior of the controlled element in the current performance using the prediction model. A work machine characterized by:

7. 7. The work machine according to claim 6, a control variable measuring device for measuring a control variable of the control target element; the controller has a prediction accuracy evaluation unit that determines whether or not a prediction error, which is a degree of deviation between a measured value of the controlled variable in a state in which the control signal correction unit does not correct the control signal and a predicted controlled variable calculated by the current behavior prediction unit, exceeds a predetermined allowable error; The learning unit executes the learning process and updates the prediction model when the prediction accuracy evaluation unit determines that the prediction error exceeds the allowable error. A work machine characterized by:

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