Shovel and shovel remote control system

Abstract

To improve security.SOLUTION: According to one embodiment of the present disclosure, a shovel includes: a lower traveling body; an upper rotating body capable of rotating with respect to the lower traveling body; a hydraulic pump; a hydraulic actuator driven by hydraulic oil discharged from the hydraulic pump; a directional control valve for switching a supply path of the hydraulic oil from the hydraulic pump to the hydraulic actuator; an electric operation device; a proportional valve capable of adjusting a pilot pressure of the hydraulic oil supplied to the directional control valve to switch the supply path; a first detection part for detecting the pilot pressure; and a control device. The control device has: a calculation part that calculates a reference value of the pilot pressure with considering time series changes in the pilot pressure over when following signals from the electric operation device, based on the signals; and a determination part that determines abnormalities related to the proportional valve according to the reference value of the pilot pressure and the detected pilot pressure.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a shovel and a remote control system for the shovel. [Background technology]

[0002] Conventionally, there has been known an excavator having an electromagnetic proportional valve that adjusts the pilot pressure of a hydraulic actuator to perform an operation according to a signal from an electric operating device. In order to prevent an operation different from the operation according to the signal from being performed due to an abnormality in the electromagnetic proportional valve, a technique has been proposed for detecting whether or not the electromagnetic proportional valve is abnormal based on the pilot pressure (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-110135 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, since the pilot pressure does not change instantly in response to a signal, there are cases where the method described in Patent Document 1 cannot appropriately determine an abnormality in the proportional solenoid valve.

[0005] One aspect of the present invention provides a technology for improving the accuracy of detecting an abnormality in a proportional valve capable of adjusting a pilot pressure, thereby improving safety. [Means for solving the problem]

[0006] According to one embodiment of the present invention, there is provided an excavator comprising a lower traveling body, an upper rotating body capable of rotating relative to the lower traveling body, a hydraulic pump, a hydraulic actuator driven by hydraulic oil discharged from the hydraulic pump, a directional control valve for switching a supply path of the hydraulic oil from the hydraulic pump to the hydraulic actuator, an electric operation device, a proportional valve capable of adjusting a pilot pressure of the hydraulic oil supplied to the directional control valve in order to switch the supply path, a first detection unit for detecting the pilot pressure, and a control device. The control device has a calculation unit for calculating a reference value of the pilot pressure based on a signal from the electric operation device, taking into account a time-series change in the pilot pressure in accordance with the signal, and a determination unit for determining an abnormality related to the proportional valve in accordance with the reference value of the pilot pressure and the detected pilot pressure. Effect of the Invention

[0007] According to one aspect of the present invention, the accuracy of detecting an abnormality in a proportional valve capable of adjusting a pilot pressure is improved, thereby improving safety. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a side view of a shovel according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of a drive control system of the shovel according to the first embodiment. [Diagram 3] 1 is a diagram showing a configuration example of a hydraulic system mounted on a shovel according to a first embodiment. FIG. [Figure 4] FIG. 2 is a diagram illustrating a hydraulic system portion related to the operation of a boom cylinder according to the first embodiment. [Diagram 5] FIG. 2 is a functional block diagram showing an example of the configuration of a controller according to the first embodiment. [Figure 6] FIG. 3 is a diagram illustrating the concept of a determination time correspondence map according to the first embodiment. [Figure 7] 5A to 5C are diagrams illustrating an abnormality determination by an abnormality detection unit according to the first embodiment, using a reference value of a pilot pressure. [Figure 8] FIG. 11 is a schematic diagram illustrating an example of a remote control system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiment described below is an example, not a limitation of the invention, and all features and combinations described in the embodiment are not necessarily essential to the invention. In addition, the same or corresponding components in each drawing are denoted by the same or corresponding reference numerals, and the description may be omitted.

[0010] In the following, in the embodiment of the present invention, an example will be described in which a shovel is used as an example of a work machine, but the present invention is not limited to a shovel. The present invention may be applied to a construction machine, a standard machine, an application machine, a forestry machine, or a conveying machine based on a hydraulic shovel.

[0011] (First embodiment) An overview of a shovel 100 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a side view of the shovel 100 as a work machine according to this embodiment.

[0012] The excavator 100 in this embodiment comprises a lower running body 1, an upper rotating body 3 mounted on the lower running body 1 so as to be freely rotatable via a rotating mechanism 2, a boom 4, an arm 5, and a bucket 6 that constitute an attachment (work machine), and a cabin 10.

[0013] The lower traveling body 1 allows the excavator 100 to travel by hydraulically driving a pair of left and right crawlers by traveling hydraulic motors 1L, 1R (see FIG. 2 described later). In other words, the pair of traveling hydraulic motors 1L, 1R (an example of a traveling motor) drive the lower traveling body 1 (crawlers) as a driven part.

[0014] The upper rotating body 3 is driven by a swing hydraulic motor 2A (see FIG. 2 described later) to swing relative to the lower traveling body 1. In other words, the swing hydraulic motor 2A is a swing drive part that drives the upper rotating body 3 as a driven part, and can change the orientation of the upper rotating body 3.

[0015] The upper rotating body 3 may be electrically driven by an electric motor (hereinafter, "electric motor for rotation") instead of the hydraulic motor for rotation 2A. In other words, the electric motor for rotation is a rotation drive part that drives the upper rotating body 3 as a non-driven part, similar to the hydraulic motor for rotation 2A, and can change the orientation of the upper rotating body 3.

[0016] The boom 4 is pivotally attached to the front center of the upper rotating body 3 so as to be able to tilt up and down, an arm 5 is pivotally attached to the tip of the boom 4 so as to be able to rotate up and down, and a bucket 6 as an end attachment is pivotally attached to the tip of the arm 5 so as to be able to rotate up and down. The boom 4, arm 5, and bucket 6 are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, each of which serves as a hydraulic actuator.

[0017] The bucket 6 is an example of an end attachment (work tool) provided at the tip of the arm 5, and specifically, is an excavation bucket, but may be a skeleton bucket or a gravel removal bucket. The bucket 6 may also be equipped with a bucket tilt mechanism.

[0018] The upper rotating body 3 is provided with a cabin 10 as a driver's cab, and is equipped with a power source such as an engine 11. An operation device 26, a controller 30, and the like are provided inside the cabin 10. In addition, an imaging device S6 and the like are attached to the upper rotating body 3.

[0019] The imaging device S6 captures images of the periphery of the shovel 100. The imaging device S6 includes a camera S6F that captures an image in front of the shovel 100, a camera S6L that captures an image to the left of the shovel 100, a camera S6R that captures an image to the right of the shovel 100, and a camera S6B that captures an image behind the shovel 100.

[0020] Camera S6F is attached, for example, to the ceiling of the cabin 10, i.e., inside the cabin 10. Camera S6F may also be attached to the outside of the cabin 10, such as to the roof of the cabin 10 or the side of the boom 4. Camera S6L is attached to the left end of the upper surface of the upper rotating body 3, camera S6R is attached to the right end of the upper surface of the upper rotating body 3, and camera S6B is attached to the rear end of the upper surface of the upper rotating body 3.

[0021] The imaging device S6 (cameras S6F, S6B, S6L, and S6R) is, for example, a monocular wide-angle camera having a very wide angle of view. The imaging device S6 may also be a stereo camera or a distance imaging camera. Images captured by the imaging device S6 are input to the controller 30.

[0022] The imaging device S6 as a spatial recognition device may function as an object detection device. In this case, the imaging device S6 may detect an object present around the shovel 100. The object to be detected may include, for example, a person, an animal, a vehicle, a construction machine, a building, a hole, and the like. The imaging device S6 may also calculate the distance from the imaging device S6 or the shovel 100 to the recognized object. The imaging device S6 as an object detection device may include, for example, a stereo camera, a distance image sensor, and the like. The spatial recognition device is, for example, a monocular camera having an imaging element such as a CCD or a CMOS, and outputs the captured image to the display device 60. The spatial recognition device may also be configured to calculate the distance from the spatial recognition device or the shovel 100 to the recognized object. In addition to the imaging device S6, other object detection devices such as, for example, an ultrasonic sensor, a millimeter wave radar, a LIDAR, and an infrared sensor may also be provided as the spatial recognition device. When using a millimeter wave radar, an ultrasonic sensor, a laser radar, or the like as a spatial recognition device, a number of signals (laser light, etc.) may be emitted to an object and the reflected signals may be received to detect the distance and direction of the object from the reflected signals.

[0023] The operating device 26 is a device used by an operator to operate the actuator. The operating device 26 includes, for example, an operating lever and an operating pedal. The actuator includes at least one of a hydraulic actuator and an electric actuator.

[0024] The input device 62 is provided within reach of an operator seated in the cabin 10, accepts various operational inputs by the operator, and outputs signals corresponding to the operational inputs to the controller 30. The input device 62 includes a touch panel or the like mounted on the display of the display device 60 that displays various information images. A signal corresponding to the content of an operation performed on the input device 62 is input to the controller 30.

[0025] The display device 60 is provided at a location where it can be easily viewed by an operator seated in the cabin 10, and displays various information images under the control of the controller 30. The display device 60 may be connected to the controller 30 via an in-vehicle communication network such as a Controller Area Network (CAN), or may be connected to the controller 30 via a one-to-one dedicated line.

[0026] The communication device T1 communicates with external devices through a predetermined network including a mobile communication network with a base station as a terminal, a satellite communication network, the Internet, etc. The communication device T1 is, for example, a mobile communication module compatible with mobile communication standards such as LTE (Long Term Evolution), 4G (4th Generation), and 5G (5th Generation), or a satellite communication module for connecting to a satellite communication network.

[0027] The controller (control device) 30 is a control device for controlling the shovel 100. For example, the controller 30 is mainly composed of a computer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a non-volatile auxiliary storage device, various input / output interfaces, etc. The controller 30 realizes various functions by reading out a program from the non-volatile storage device, loading it into a volatile storage device, and having the CPU execute the program. The various functions include, for example, a machine guidance function that guides the operator in manually operating the shovel 100. The controller 30 may include a contact avoidance function that automatically or autonomously operates or stops the shovel 100 to avoid contact between the shovel 100 and an object present within a monitoring range around the shovel 100.

[0028] For example, the controller 30 sets a target rotation speed based on an operation by an operator or the like, and performs drive control to rotate the engine 11 at a constant speed.

[0029] The boom angle sensor S1 is attached to the boom 4 and detects the elevation angle of the boom 4 relative to the upper rotating body 3 (hereinafter referred to as the "boom angle"), for example, the angle formed by a straight line connecting the fulcrums at both ends of the boom 4 relative to the rotation plane of the upper rotating body 3 in a side view. The boom angle sensor S1 may include, for example, a rotary encoder, an acceleration sensor, a six-axis sensor, an IMU (Inertial Measurement Unit), etc. The boom angle sensor S1 may also include a potentiometer using a variable resistor, a cylinder stroke sensor that detects the stroke amount of a hydraulic cylinder (boom cylinder 7) corresponding to the boom angle, etc. The same applies to the arm angle sensor S2 and the bucket angle sensor S3 below. A detection signal corresponding to the boom angle by the boom angle sensor S1 is taken into the controller 30.

[0030] The arm angle sensor S2 is attached to the arm 5 and detects the rotation angle of the arm 5 relative to the boom 4 (hereinafter referred to as the “arm angle”), for example, the angle formed by a line connecting the fulcrums at both ends of the arm 5 with respect to a line connecting the fulcrums at both ends of the boom 4 in a side view. A detection signal corresponding to the arm angle by the arm angle sensor S2 is input to the controller 30.

[0031] The bucket angle sensor S3 is attached to the bucket 6 and detects the rotation angle of the bucket 6 with respect to the arm 5 (hereinafter referred to as the “bucket angle”), for example, the angle formed by a line connecting the fulcrum of the bucket 6 and its tip (tip) with respect to a line connecting the fulcrums of both ends of the arm 5 in a side view. A detection signal corresponding to the bucket angle by the bucket angle sensor S3 is input to the controller 30.

[0032] The machine body tilt sensor S4 (an example of an attitude detection unit) detects the tilt state of the machine body (upper rotating body 3 or lower running body 1) with respect to a horizontal plane. The machine body tilt sensor S4 is attached to, for example, the upper rotating body 3, and detects the tilt angles around two axes in the forward / backward and left / right directions (hereinafter, "fore / aft tilt angle" and "left / right tilt angle") of the shovel 100 (i.e., upper rotating body 3). The machine body tilt sensor S4 may include, for example, a rotary encoder, an acceleration sensor, a six-axis sensor, an IMU, etc. A detection signal corresponding to the tilt angle (fore / aft tilt angle and left / right tilt angle) by the machine body tilt sensor S4 is input to the controller 30.

[0033] The rotation angle sensor S5 outputs detection information related to the rotation state of the upper rotating body 3. The rotation angle sensor S5 detects, for example, the rotation angular velocity and rotation angle of the upper rotating body 3. The rotation angle sensor S5 may include, for example, a gyro sensor, a resolver, a rotary encoder, etc. A detection signal corresponding to the rotation angle and the rotation angular velocity of the upper rotating body 3 detected by the rotation angle sensor S5 is input to the controller 30.

[0034] A boom rod pressure sensor S7R and a boom bottom pressure sensor S7B are attached to the boom cylinder 7. An arm rod pressure sensor S8R and an arm bottom pressure sensor S8B are attached to the arm cylinder 8. A bucket rod pressure sensor S9R and a bucket bottom pressure sensor S9B are attached to the bucket cylinder 9. The boom rod pressure sensor S7R, the boom bottom pressure sensor S7B, the arm rod pressure sensor S8R, the arm bottom pressure sensor S8B, the bucket rod pressure sensor S9R and the bucket bottom pressure sensor S9B are collectively referred to as "cylinder pressure sensors."

[0035] The boom rod pressure sensor S7R detects the pressure in the rod side oil chamber of the boom cylinder 7 (hereinafter referred to as the "boom rod pressure"), and the boom bottom pressure sensor S7B detects the pressure in the bottom side oil chamber of the boom cylinder 7 (hereinafter referred to as the "boom bottom pressure"). The arm rod pressure sensor S8R detects the pressure in the rod side oil chamber of the arm cylinder 8 (hereinafter referred to as the "arm rod pressure"), and the arm bottom pressure sensor S8B detects the pressure in the bottom side oil chamber of the arm cylinder 8 (hereinafter referred to as the "arm bottom pressure"). The bucket rod pressure sensor S9R detects the pressure in the rod side oil chamber of the bucket cylinder 9 (hereinafter referred to as the "bucket rod pressure"), and the bucket bottom pressure sensor S9B detects the pressure in the bottom side oil chamber of the bucket cylinder 9 (hereinafter referred to as the "bucket bottom pressure").

[0036] The positioning device PS measures the position and orientation of the upper rotating body 3. The positioning device PS is, for example, a Global Navigation Satellite System (GNSS) compass, and detects the position and orientation of the upper rotating body 3, and a detection signal corresponding to the position and orientation of the upper rotating body 3 is input to the controller 30. Furthermore, among the functions of the positioning device PS, the function of detecting the orientation of the upper rotating body 3 may be substituted by a direction sensor attached to the upper rotating body 3.

[0037] [Excavator drive control system] Fig. 2 is a diagram showing an example of the configuration of a drive control system of the excavator 100 in Fig. 1. In Fig. 2, a mechanical power transmission system is indicated by a double line, a hydraulic oil line is indicated by a thick solid line, a pilot line is indicated by a dashed line, and an electric drive and control system is indicated by a dotted line.

[0038] The drive system of the excavator 100 according to this embodiment includes the engine 11, the regulator 13, the main pump 14, and the control valve unit 17. As described above, the hydraulic drive system of the excavator 100 according to this embodiment includes hydraulic actuators such as the traveling hydraulic motors 1L, 1R, the swing hydraulic motor 2A, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9, which hydraulically drive the lower traveling body 1, the upper rotating body 3, the boom 4, the arm 5, and the bucket 6, respectively. These hydraulic actuators are driven by hydraulic oil discharged from the main pump 14.

[0039] The engine 11 is a main power source in the hydraulic drive system, and is mounted, for example, on the rear of the upper rotating body 3. Specifically, the engine 11 rotates at a constant speed at a preset target speed under direct or indirect control by a controller 30 (described later), and drives the main pump 14 and the pilot pump 15. The engine 11 is, for example, a diesel engine that uses diesel as fuel.

[0040] The regulator 13 controls the discharge amount of the main pump 14. For example, the regulator 13 adjusts the angle (tilt angle) of the swash plate of the main pump 14 in response to a control command from the controller 30. The regulator 13 includes, for example, regulators 13L and 13R, as described below.

[0041] The main pump 14 is mounted on the rear of the upper rotating body 3, for example, like the engine 11, and supplies hydraulic oil to the control valve unit 17 through a high-pressure hydraulic line. The main pump 14 is driven by the engine 11 as described above. The main pump 14 is, for example, a variable displacement hydraulic pump, and as described above, under the control of the controller 30, the tilt angle of the swash plate is adjusted by the regulator 13 to adjust the stroke length of the piston, thereby controlling the discharge flow rate (discharge pressure). The main pump 14 includes, for example, main pumps 14L and 14R, as described below.

[0042] The control valve unit 17 is a hydraulic control device that controls the hydraulic system in the excavator 100. In this embodiment, the control valve unit 17 includes control valves 171-176. The control valve unit 17 is configured to selectively supply the hydraulic oil discharged by the main pump 14 to one or more hydraulic actuators through the control valves 171-176.

[0043] The control valves 171 to 176 are a type of directional control valve that switches the supply path of hydraulic oil from the main pump 14 to the hydraulic actuators, and control, for example, the flow rate of hydraulic oil flowing from the main pump 14 to the hydraulic actuators and the flow rate of hydraulic oil flowing from the hydraulic actuators to a hydraulic oil tank. The hydraulic actuators include a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, traveling hydraulic motors 1L and 1R, and a swing hydraulic motor 2A. More specifically, the control valve 171 corresponds to the left traveling hydraulic motor 1L, the control valve 172 corresponds to the right traveling hydraulic motor 1R, and the control valve 173 corresponds to the swing hydraulic motor 2A. In addition, the control valve 174 corresponds to the bucket cylinder 9, the control valve 175 corresponds to the boom cylinder 7, and the control valve 176 corresponds to the arm cylinder 8.

[0044] The pilot pump 15 is an example of a pilot pressure generating device, and is configured to be able to supply hydraulic oil to the hydraulic control device via a pilot line. In this embodiment, the pilot pump 15 is a fixed displacement hydraulic pump. However, the pilot pressure generating device may be realized by the main pump 14. That is, the main pump 14 may have a function of supplying hydraulic oil to various hydraulic control devices via a pilot line, in addition to a function of supplying hydraulic oil to the control valve unit 17 via a hydraulic oil line. In this case, the pilot pump 15 may be omitted.

[0045] In the hydraulic system of the excavator 100, a gate lock control valve 33 is provided midway in a pilot pipeline connecting the pilot pump 15 and the proportional valve 31. When a gate lock switch (not shown) is in the off state, in other words, when a gate lock lever is in the locked position, the gate lock control valve 33 stops the supply of hydraulic oil (pilot pressure oil) from the pilot pump 15 to the proportional valve 31. In addition, the gate lock control valve 33 can stop the supply of hydraulic oil (pilot pressure oil) from the pilot pump 15 to the proportional valve 31 in response to a signal from the controller 30.

[0046] The operating device 26 is an example of an electric operating device that an operator uses to operate an actuator. The actuator includes at least one of a hydraulic actuator and an electric actuator.

[0047] The discharge pressure sensor 28 is configured to detect the discharge pressure of the main pump 14. In this embodiment, the discharge pressure sensor 28 outputs the detected value to the controller 30.

[0048] The operation sensor 29 is configured to detect the operation content of the operator using the operating device 26. In this embodiment, the operation sensor 29 detects the operation direction and operation amount of the operating device 26 corresponding to each actuator, and outputs the detected value to the controller 30. In this embodiment, the controller 30 controls the opening area of ​​the proportional valve 31 according to the output of the operation sensor 29. Then, the controller 30 supplies the hydraulic oil discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17. The pressure of the hydraulic oil (pilot pressure) supplied to each pilot port is, in principle, a pressure according to the operation direction and operation amount of the operating device 26 corresponding to each hydraulic actuator. In this way, the operating device 26 is configured to be able to supply the hydraulic oil discharged by the pilot pump 15 to the pilot port of the corresponding control valve in the control valve unit 17.

[0049] The proportional valve 31, which functions as a control valve for machine control, is disposed in a pipe connecting the pilot pump 15 and the pilot port of the control valve in the control valve unit 17, and is configured so that the flow path area of ​​the pipe can be changed. In this embodiment, the proportional valve 31 operates in response to a control command output by the controller 30.

[0050] The controller 30 is configured to control the opening and closing of the proportional valve 31 according to a signal input from the operation sensor 29, and to supply the hydraulic oil discharged by the pilot pump 15 to the pilot ports of the corresponding control valves 171-176 in the control valve unit 17 via a pilot line. When the operator operates the operation device 26, the pressure of the hydraulic oil (pilot pressure) supplied to each pilot port is a pressure according to the operation direction and operation amount of the operation device 26 corresponding to each hydraulic actuator. In other words, the proportional valve 31 adjusts the pilot pressure supplied to the pilot ports of the control valves 171-176 based on the signal received from the operation sensor 29 in order to switch the supply path by the control valves 171-176.

[0051] The controller 30 can apply the pilot pressure generated by the proportional valve 31 to the pilot port of the corresponding control valve. Therefore, the controller 30 can supply the hydraulic oil discharged by the pilot pump 15 to the pilot port of the control valve in the control valve unit 17 via the proportional valve 31, regardless of the operation of the operating device 26 by the operator.

[0052] With this configuration, the controller 30 can operate the hydraulic actuator corresponding to a specific operating device 26 even when no operation is being performed on that specific operating device 26. Furthermore, the controller 30 can forcibly stop the operation of the hydraulic actuator corresponding to that specific operating device 26 even when an operation is being performed on that specific operating device 26.

[0053] For example, when the controller 30 is configured to perform autonomous control over the shovel 100, it sets one or more of a target rotation angle for the upper rotating body 3, target angles for each of the upper rotating body 3, the boom 4, the arm 5, and the bucket 6, and a target rotation speed for the engine 11 based on the operations performed by the autonomous control, and controls the operation of various components of the shovel 100.

[0054] Furthermore, for example, the controller 30 outputs a control command to the regulator 13 as necessary to change the discharge amount of the main pump 14.

[0055] In addition, for example, the controller 30 performs control related to a machine guidance function that guides (guides) the manual operation of the shovel 100 by the operator through the operation device 26. In addition, the controller 30 performs control related to a machine control function that automatically assists the manual operation of the shovel 100 by the operator through the operation device 26.

[0056] Note that some of the functions of the controller 30 may be realized by another controller (control device). That is, the functions of the controller 30 may be realized in a distributed manner by a plurality of controllers. For example, the machine guidance function and the machine control function may be realized by a dedicated controller (control device).

[0057] [Excavator hydraulic system] Next, a configuration example of a hydraulic system mounted on the shovel 100 will be described with reference to Fig. 3. Fig. 3 is a diagram showing a configuration example of a hydraulic system mounted on the shovel 100. In Fig. 3, a mechanical power transmission system, a hydraulic oil line, a pilot line, and an electric control system are indicated by double lines, solid lines, dashed lines, and dotted lines, respectively.

[0058] The hydraulic system of the excavator 100 mainly includes an engine 11, a regulator 13, a main pump 14, a pilot pump 15, a control valve unit 17, an operating device 26, a discharge pressure sensor 28, an operation sensor 29, a controller 30, and the like.

[0059] In FIG. 3, the hydraulic system is configured to circulate hydraulic oil from a main pump 14 driven by an engine 11 through a center bypass line 40 or a parallel line 42 to a hydraulic oil tank.

[0060] The main pump (hydraulic pump) 14 is configured to supply hydraulic oil via a hydraulic oil line to the control valve unit 17. In this embodiment, the main pump 14 is a swash plate type variable displacement hydraulic pump.

[0061] In this embodiment, the control valve unit 17 includes control valves (directional control valves) 171-176. The control valve 175 includes a control valve 175L and a control valve 175R, and the control valve 176 includes a control valve 176L and a control valve 176R. The control valve unit 17 is configured to selectively supply the hydraulic oil discharged by the main pump 14 to one or more hydraulic actuators through the control valves 171-176.

[0062] The main pump 14 includes a left main pump 14L and a right main pump 14R. The left main pump 14L circulates hydraulic oil to a hydraulic oil tank via a left center bypass line 40L or a left parallel line 42L, and the right main pump 14R circulates hydraulic oil to a hydraulic oil tank via a right center bypass line 40R or a right parallel line 42R.

[0063] The left center bypass line 40L is a hydraulic oil line that passes through control valves 171, 173, 175L, and 176L arranged in the control valve unit 17. The right center bypass line 40R is a hydraulic oil line that passes through control valves 172, 174, 175R, and 176R arranged in the control valve unit 17.

[0064] The control valve 171 is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the left main pump 14L to the left traveling hydraulic motor 2ML and to discharge the hydraulic oil discharged by the left traveling hydraulic motor 2ML to the hydraulic oil tank.

[0065] The control valve 172 is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the right main pump 14R to the right traveling hydraulic motor 2MR and to discharge the hydraulic oil discharged by the right traveling hydraulic motor 2MR to the hydraulic oil tank.

[0066] The control valve 173 is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the left main pump 14L to the swing hydraulic motor 2A and to discharge the hydraulic oil discharged by the swing hydraulic motor 2A to the hydraulic oil tank.

[0067] The control valve 174 is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the right main pump 14R to the bucket cylinder 9 and to discharge the hydraulic oil in the bucket cylinder 9 to the hydraulic oil tank.

[0068] The control valve 175L is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the left main pump 14L to the boom cylinder 7. The control valve 175R is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the right main pump 14R to the boom cylinder 7 and to discharge the hydraulic oil in the boom cylinder 7 to the hydraulic oil tank.

[0069] The control valve 176L is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the left main pump 14L to the arm cylinder 8 and to discharge the hydraulic oil in the arm cylinder 8 to the hydraulic oil tank.

[0070] The control valve 176R is a spool valve that switches the flow of hydraulic oil to supply the hydraulic oil discharged by the right main pump 14R to the arm cylinder 8 and to discharge the hydraulic oil in the arm cylinder 8 to the hydraulic oil tank.

[0071] The left parallel conduit 42L is a hydraulic oil line that runs parallel to the left center bypass conduit 40L. The left parallel conduit 42L can supply hydraulic oil to a more downstream control valve when the flow of hydraulic oil through the left center bypass conduit 40L is restricted or blocked by any of the control valves 171, 173, and 175L. The right parallel conduit 42R is a hydraulic oil line that runs parallel to the right center bypass conduit 40R. The right parallel conduit 42R can supply hydraulic oil to a more downstream control valve when the flow of hydraulic oil through the right center bypass conduit 40R is restricted or blocked by any of the control valves 172, 174, and 175R.

[0072] The regulator 13 includes a left regulator 13L and a right regulator 13R. The left regulator 13L controls the discharge amount of the left main pump 14L by adjusting the swash plate tilt angle of the left main pump 14L according to the discharge pressure of the left main pump 14L. Specifically, the left regulator 13L adjusts the swash plate tilt angle of the left main pump 14L in response to an increase in the discharge pressure of the left main pump 14L, for example, to reduce the discharge amount. The same is true for the right regulator 13R. This is to prevent the absorption power (absorption horsepower) of the main pump 14, which is expressed by the product of the discharge pressure and the discharge amount, from exceeding the output power (output horsepower) of the engine 11.

[0073] The operating device 26 includes a left operating lever 26L, a right operating lever 26R, and a travel lever 26D. The travel lever 26D includes a left traveling lever 26DL and a right traveling lever 26DR.

[0074] The operation sensor 29 includes operation sensors 29LA, 29LB, 29RA, 29RB, 29DL, and 29DR.

[0075] The left operating lever 26L is used for the rotation operation and the operation of the arm 5. When the left operating lever 26L is operated in the forward / backward direction, the hydraulic oil discharged by the pilot pump 15 is used to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 176. When the left operating lever 26L is operated in the left / right direction, the hydraulic oil discharged by the pilot pump 15 is used to introduce a control pressure according to the amount of lever operation into the pilot port of the control valve 173.

[0076] The operation sensor 29LA detects the content of the operation of the left operation lever 26L in the forward / rearward direction by the operator, and outputs the detected value to the controller 30.

[0077] The operation sensor 29LB detects the content of the operation of the left operation lever 26L in the left or right direction by the operator, and outputs the detected value to the controller 30.

[0078] When the left operating lever 26L is operated in the arm closing direction, the controller 30 controls the proportional valve 31 according to a signal from the operation sensor 29LA to introduce hydraulic oil into the right pilot port of the control valve 176L and to introduce hydraulic oil into the left pilot port of the control valve 176R. When the left operating lever 26L is operated in the arm opening direction, the controller 30 controls the proportional valve 31 according to a signal from the operation sensor 29LA to introduce hydraulic oil into the left pilot port of the control valve 176L and to introduce hydraulic oil into the right pilot port of the control valve 176R.

[0079] In addition, when the left operating lever 26L is operated in the left turning direction, the controller 30 controls the proportional valve 31 in accordance with a signal from the operation sensor 29LB to introduce hydraulic oil into the left pilot port of the control valve 173, and when the left operating lever 26L is operated in the right turning direction, the controller 30 controls the proportional valve 31 in accordance with a signal from the operation sensor 29LB to introduce hydraulic oil into the right pilot port of the control valve 173.

[0080] In addition, a switch NS is provided on the left operation lever 26L. In this embodiment, the switch NS is a push button switch provided on the tip of the left operation lever 26L. The operator can operate the left operation lever 26L while pressing the switch NS. The switch NS may be provided on the right operation lever 26R or may be provided at another position in the cabin 10.

[0081] The right operating lever 26R is used to operate the boom 4 and the bucket 6. When the right operating lever 26R is operated in the forward / backward direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure corresponding to the amount of lever operation into the pilot port of the control valve 175. When the right operating lever 26R is operated in the left / right direction, it uses the hydraulic oil discharged by the pilot pump 15 to introduce a control pressure corresponding to the amount of lever operation into the pilot port of the control valve 174.

[0082] The operation sensor 29RA detects the content of the operation of the right operating lever 26R in the forward / rearward direction by the operator, and outputs the detected value to the controller 30.

[0083] The operation sensor 29RB detects the content of the operation of the right operating lever 26R in the left or right direction by the operator, and outputs the detected value to the controller 30.

[0084] Specifically, when the right operating lever 26R is operated in the boom-down direction, the controller 30 controls the proportional valve 31 in accordance with a signal from the operation sensor 29RA to introduce hydraulic oil into the left pilot port of the control valve 175L and to introduce hydraulic oil into the right pilot port of the control valve 175R. Also, when the right operating lever 26R is operated in the boom-up direction, the controller 30 controls the proportional valve 31 in accordance with a signal from the operation sensor 29RA to introduce hydraulic oil into the right pilot port of the control valve 175L and to introduce hydraulic oil into the left pilot port of the control valve 175R.

[0085] In addition, when the right operating lever 26R is operated in the bucket closing direction, the controller 30 controls the proportional valve 31 in accordance with a signal from the operation sensor 29RB to introduce hydraulic oil into the right pilot port of the control valve 174, and when the right operating lever 26R is operated in the bucket opening direction, the controller 30 controls the proportional valve 31 in accordance with a signal from the operation sensor 29RB to introduce hydraulic oil into the left pilot port of the control valve 174.

[0086] The travel lever 26D is used to operate the crawlers. Specifically, the left travel lever 26DL is used to operate the left crawler. It may be configured to be linked to the left travel pedal.

[0087] The operation sensor 29DL detects the operation of the left travel lever 26DL in the forward / rearward direction by the operator, and outputs the detected value to the controller 30.

[0088] When the left travel lever 26DL is operated in the forward / rearward direction, the controller 30 controls the proportional valve 31 in accordance with a signal from the operation sensor 29DL to use the hydraulic oil discharged from the pilot pump 15 to introduce a control pressure corresponding to the amount of lever operation into the pilot port of the control valve 171.

[0089] The right travel lever 26DR is used to operate the right crawler and may be configured to be interlocked with the right travel pedal.

[0090] The operation sensor 29DR detects the operation of the right travel lever 26DR in the forward or backward direction by the operator, and outputs the detected value to the controller 30.

[0091] When the right travel lever 26DR is operated in the forward / rearward direction, the controller 30 controls the proportional valve 31 in accordance with a signal from the operation sensor 29DR to use the hydraulic oil discharged from the pilot pump 15 to introduce a control pressure corresponding to the amount of lever operation into the pilot port of the control valve 172.

[0092] The discharge pressure sensor 28 includes a discharge pressure sensor 28L and a discharge pressure sensor 28R. The discharge pressure sensor 28L detects the discharge pressure of the left main pump 14L and outputs the detected value to the controller 30. The same applies to the discharge pressure sensor 28R.

[0093] The controller 30 receives the output of the operation sensor 29, and outputs a control command to the regulator 13 as necessary, thereby changing the discharge volume of the main pump 14. The controller 30 also receives the output of a control pressure sensor 19 provided upstream of the throttle (negative control throttle) 18, and outputs a control command to the regulator 13 as necessary, thereby changing the discharge volume of the main pump 14. The throttle 18 includes a left throttle 18L and a right throttle 18R, and the control pressure sensor 19 includes a left control pressure sensor 19L and a right control pressure sensor 19R.

[0094] The left center bypass pipe 40L is provided with a left throttle 18L between the most downstream control valve 176L and the hydraulic oil tank. Therefore, the flow of hydraulic oil discharged by the left main pump 14L is restricted by the left throttle 18L. The left throttle 18L generates a control pressure for controlling the left regulator 13L. The left control pressure sensor 19L is a sensor for detecting this control pressure, and outputs the detected value to the controller 30. The controller 30 controls the discharge amount of the left main pump 14L by adjusting the swash plate tilt angle of the left main pump 14L according to this control pressure. The controller 30 reduces the discharge amount of the left main pump 14L as this control pressure increases, and increases the discharge amount of the left main pump 14L as this control pressure decreases. The discharge amount of the right main pump 14R is also controlled in a similar manner.

[0095] Specifically, as shown in FIG. 3, in the case of a standby state in which none of the hydraulic actuators in the excavator 100 are operated, the hydraulic oil discharged by the left main pump 14L passes through the left center bypass pipe 40L and reaches the left throttle 18L. Then, the flow of the hydraulic oil discharged by the left main pump 14L increases the control pressure generated upstream of the left throttle 18L. As a result, the controller 30 reduces the discharge amount of the left main pump 14L to the allowable minimum discharge amount, suppressing the pressure loss (pumping loss) when the discharged hydraulic oil passes through the left center bypass pipe 40L. On the other hand, when any of the hydraulic actuators is operated, the hydraulic oil discharged by the left main pump 14L flows into the hydraulic actuator to be operated through the control valve corresponding to the hydraulic actuator to be operated. Then, the flow of the hydraulic oil discharged by the left main pump 14L reduces or eliminates the amount of hydraulic oil reaching the left throttle 18L, lowering the control pressure generated upstream of the left throttle 18L. As a result, the controller 30 increases the discharge rate of the left main pump 14L to circulate sufficient hydraulic oil to the hydraulic actuator to be operated, ensuring the drive of the hydraulic actuator to be operated. The controller 30 also controls the discharge rate of the right main pump 14R in a similar manner.

[0096] With the above-described configuration, the hydraulic system of Fig. 3 can suppress unnecessary energy consumption in the main pump 14 in a standby state. The unnecessary energy consumption includes pumping loss caused in the center bypass pipe 40 by the hydraulic oil discharged from the main pump 14. Furthermore, when operating a hydraulic actuator, the hydraulic system of Fig. 3 can reliably supply necessary and sufficient hydraulic oil from the main pump 14 to the hydraulic actuator to be operated.

[0097] That is, the controller 30 controls the regulator 13 so that the discharge amount is the smaller of a first discharge amount calculated so that the absorption power (absorption horsepower) of the main pump 14, which is expressed as the product of the discharge pressure and the discharge amount, does not exceed the output power (output horsepower) of the engine 11, and a second discharge amount calculated based on the control pressure detected by the control pressure sensor 19.

[0098] Next, a configuration for the controller 30 to operate the actuators using the machine control function will be described with reference to Fig. 4. Fig. 4 is a diagram of a part of the hydraulic system. Specifically, Fig. 4 is a diagram of the hydraulic system portion related to the operation of the boom cylinder 7 according to this embodiment.

[0099] 4, in the hydraulic system, the gate lock control valve 33 is provided in the middle of a pilot line that connects the pilot pump 15 and the proportional valve 31. The control of the gate lock control valve 33 is as described above, so a description thereof will be omitted.

[0100] 4, the hydraulic system includes a proportional valve 31. The proportional valve 31 includes proportional valves 31BL and 31BR.

[0101] The proportional valve 31BL operates in response to a control command (current command) output by the controller 30. The proportional valve 31BL adjusts the pilot pressure by the hydraulic oil introduced from the pilot pump 15 to the left pilot port of the control valve 175R via the proportional valve 31BL. The proportional valve 31BR operates in response to a control command (current command) output by the controller 30. The proportional valve 31BR adjusts the pilot pressure by the hydraulic oil introduced from the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR. The proportional valve 31BL can adjust the pilot pressure so that the control valve 175R can be stopped at any valve position. The proportional valve 31BR can adjust the pilot pressure so that the control valve 175R can be stopped at any valve position.

[0102] A pilot pressure sensor 32BL for detecting pilot pressure is provided in a pilot line connecting the proportional valve 31BL and one port of the control valve 175 (the left port of the control valve 175R). A pilot pressure sensor 32BR for detecting pilot pressure is provided in a pilot line connecting the proportional valve 31BR and the other port of the control valve 175 (the right port of the control valve 175R). Values ​​detected by the pilot pressure sensors (examples of first detection units) 32BL, 32BR (hereinafter also referred to as pilot pressure sensor 32) are transmitted to the controller 30.

[0103] With this configuration, controller 30 can supply hydraulic oil discharged from pilot pump 15 to the left pilot port of control valve 175R via proportional valve 31BL in response to a boom-raising operation by the operator. Also, controller 30 can supply hydraulic oil discharged from pilot pump 15 to the left pilot port of control valve 175R via proportional valve 31BL, regardless of a boom-raising operation by the operator. In other words, controller 30 can raise boom 4 in response to a boom-raising operation by the operator or regardless of a boom-raising operation by the operator.

[0104] Furthermore, the controller 30 can detect an abnormality based on the pilot pressures detected by the pilot pressure sensors 32BL, 32BR. The detection of an abnormality will be described later.

[0105] Furthermore, the controller 30 can supply the hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR in response to the boom lowering operation by the operator. Furthermore, the controller 30 can supply the hydraulic oil discharged by the pilot pump 15 to the right pilot port of the control valve 175R via the proportional valve 31BR, regardless of the boom lowering operation by the operator. In other words, the controller 30 can lower the boom 4 in response to the boom lowering operation by the operator or regardless of the boom lowering operation by the operator.

[0106] 4, the configuration in which the controller 30 controls the proportional valves 31BL, 31BR and supplies the pilot pressure to the control valve 175R has been described. Similarly, the controller 30 controls a proportional valve (not shown) and supplies the pilot pressure to the control valve 175L.

[0107] Furthermore, with this configuration, even when the operator is performing a boom-raising operation, the controller 30 can, as necessary, reduce the pilot pressure acting on the boom-raising side pilot ports of the control valve 175 (the left pilot port of the control valve 176R and the right pilot port of the control valve 175L) to forcibly stop the raising operation of the boom 4. The same applies to the case where the lowering operation of the boom 4 is forcibly stopped when the operator is performing a boom-lowering operation.

[0108] A temperature sensor (an example of a second detection unit) 34 that detects the temperature of the hydraulic oil flowing through the pilot line connecting the pilot pump 15 and the proportional valves 31 (31BL, 31BR) is provided in the pilot line. The temperature detected by the temperature sensor 34 is transmitted to the controller 30.

[0109] Although detailed description will be omitted, the same applies to the case where the operation of the arm 5 is forcibly stopped when the operator is performing an arm opening operation or an arm closing operation, the case where the operation of the bucket 6 is forcibly stopped when the operator is performing a bucket closing operation or a bucket opening operation, and the case where the rotation operation of the upper rotating body 3 is forcibly stopped when the operator is performing a rotation operation, and the case where the traveling operation of the lower traveling body 1 is forcibly stopped when the operator is performing a traveling operation.

[0110] The excavator 100 may be configured to automatically move the lower traveling structure 1 forward and backward. In this case, the hydraulic system portion related to the operation of the left traveling hydraulic motor 2ML and the hydraulic system portion related to the operation of the right traveling hydraulic motor 2MR may be configured in the same manner as the hydraulic system portion related to the operation of the boom cylinder 7, etc.

[0111] Although the description has been given of an electric control lever as a form of the operation device 26, a hydraulic operation lever may be adopted instead of the electric operation lever. In this case, the lever operation amount of the hydraulic operation lever may be detected in the form of pressure by a pressure sensor and input to the controller 30. Also, a solenoid valve may be disposed between the operation device 26 as a hydraulic operation lever and the pilot port of each control valve. The solenoid valve is configured to operate in response to an electric signal from the controller 30. With this configuration, when manual operation is performed using the operation device 26 as a hydraulic operation lever, the operation device 26 can move each control valve by increasing or decreasing the pilot pressure in response to the lever operation amount. Also, each control valve may be configured as an electromagnetic spool valve. In this case, the electromagnetic spool valve operates in response to an electric signal from the controller 30 corresponding to the lever operation amount of the electric operation lever.

[0112] [Function configuration for detecting proportional valve abnormalities] The controller 30 according to this embodiment controls the opening area of ​​the proportional valve 31 based on a signal input from the operation sensor 29 .

[0113] Conventionally, in an (electromagnetic) proportional valve, there has been a possibility that a sticking phenomenon may occur in which the drive part stops moving due to the intrusion of foreign matter inside the valve, and the valve body stops moving.

[0114] The sticking phenomenon includes, for example, an abnormality called "closed side sticking" in which the proportional valve remains closed or the proportional valve remains at a small opening despite the controller sending a control signal to open the proportional valve in response to the lever operation of the operation device. In this case, for example, an abnormality occurs in which the boom does not move even though the operation to raise the boom is being performed with the operation device.

[0115] Another example is an abnormality called "stuck on open side" in which the proportional valve remains open even though the controller has sent a control signal to close the proportional valve because the lever on the control device has not been operated. In this case, for example, an abnormality occurs in which the boom continues to raise even though the control device has been returned to the neutral position.

[0116] In order to detect the abnormality, for example, a method of diagnosing an abnormality when the difference between a command value indicating a (target) pilot pressure based on a signal from an operation sensor and an actual pilot pressure detected by a pressure sensor provided in a pilot line is greater than or equal to a predetermined threshold value is considered. However, when using this method, it is difficult to set an appropriate threshold value. For example, if the threshold value is made small, an abnormality can be detected with a small difference, but since a phase delay occurs in a hydraulic system, even if the system is operating normally, the actual pilot pressure may not follow the command value, and an abnormality may be erroneously determined. On the other hand, if the threshold value is made large, erroneous detection when the system is operating normally can be suppressed, but if an abnormality actually occurs, there may be a delay before the abnormality is determined.

[0117] Therefore, the controller 30 according to the present embodiment regards the hydraulic system as a first-order lag system, and calculates a reference value of the pilot pressure based on a command value of the pilot pressure generated according to a signal received from the operation sensor 29, taking into consideration a time-series change in the pilot pressure when the command is followed. The controller 30 then determines whether or not an abnormality has occurred in the proportional valve 31 according to the reference value of the pilot pressure and the pilot pressure detected by the pilot pressure sensor 32. In this embodiment, the hydraulic system is regarded as a first-order lag system, and determines whether or not an abnormality has occurred using a reference value of the pilot pressure estimated to be actually output in response to the operation received by the operating device 26. This allows the abnormality to be appropriately detected regardless of whether the lever operation is sudden or not.

[0118] Next, various functional elements of the controller 30 of the shovel 100 will be described with reference to Fig. 5. Fig. 5 is a functional block diagram showing an example of the configuration of the controller 30 according to this embodiment.

[0119] As shown in FIG. 5, the controller 30 includes a pilot command generating unit 351, a current generating unit 352, and an abnormality detecting unit 300.

[0120] The pilot command generating unit 351 generates a command value for the pilot pressure based on the operation content of the operating device 26 detected by the operation sensor 29. The command value for the pilot pressure is set as a target value for the pilot pressure to be applied to the pilot ports of the control valves 171-175.

[0121] The current generating unit 352 generates a control current corresponding to the command value of the pilot pressure generated by the pilot command generating unit 351, and outputs the generated control current to the proportional valve 31. This enables the proportional valve 31 to apply the pilot pressure corresponding to the command value of the pilot pressure to the corresponding pilot port of the control valves 171 to 175.

[0122] The abnormality detection unit 300 includes a time constant output unit 301, a judgment time output unit 302, a judgment threshold output unit 303, a first-order low-pass filter 304, a calculator 305, a positive / negative judgment unit 306, an absolute value calculation unit 307, a comparison calculation unit 308, a timer 309, a comparison calculation unit 310, and a command output unit 311.

[0123] The determination time output unit 302 includes a determination time correspondence map 302A, and outputs a determination time based on the temperature of the hydraulic oil received from the temperature sensor 34 to the comparison calculation unit 310. The determination time is the time required to determine that an abnormality has occurred with respect to the proportional valve 31. The specific determination will be described later.

[0124] The determination time correspondence map 302A is a two-dimensional map in which the temperature and the determination time are associated with each other. Fig. 6 is a diagram illustrating the concept of the determination time correspondence map 302A according to this embodiment.

[0125] In the example shown in FIG. 6, the vertical axis represents the judgment time, and the horizontal axis represents the temperature. However, when the temperature of the hydraulic oil is low, the viscosity of the hydraulic oil in the hydraulic system increases, and the responsiveness to the operation lever decreases. For this reason, as shown in FIG. 6, when the temperature of the hydraulic oil is low, a high value is set as the judgment time. As the temperature of the hydraulic oil increases, the value of the judgment time decreases. However, even if the temperature of the hydraulic oil increases with a predetermined temperature as a reference, the viscosity of the hydraulic oil does not change much. Therefore, as shown in FIG. 6, in the judgment time correspondence map 302A, when the temperature of the hydraulic oil is higher than the predetermined temperature, the judgment time is set to be approximately the same. Note that the judgment time correspondence map 302A according to this embodiment is an example, and is not limited to this correspondence. The correspondence relationship between the temperature and the judgment time may be shown, for example, as a negative correlation, may be shown linearly, or may be shown nonlinearly. In other words, it is sufficient to specify the judgment time corresponding to the temperature of the hydraulic oil.

[0126] Then, the determination time output unit 302 can specify a determination time corresponding to the received hydraulic oil temperature by referring to the determination time correspondence map 302A, and output the specified determination time to the comparison calculation unit 310.

[0127] The time constant output unit 301 includes a time constant correspondence map 301A, and outputs a time constant based on the temperature of the hydraulic oil received from the temperature sensor 34 to the primary low-pass filter 304. As described above, the viscosity of the hydraulic oil flowing through the hydraulic system changes depending on the temperature. Therefore, the response of the hydraulic system changes depending on the temperature of the hydraulic oil. Therefore, the time constant output unit 301 according to this embodiment outputs a time constant corresponding to the temperature of the hydraulic oil to the primary low-pass filter 304 in order to respond to the change in the response.

[0128] The time constant correspondence map 301A is a two-dimensional map that associates temperature with a time constant. The correspondence between temperature and time constant in the time constant correspondence map 301A may be substantially the same as the correspondence between temperature and determination time shown in FIG. 6. Note that the time constant correspondence map 301A according to the present embodiment is merely an example, and is not limited to this correspondence. In other words, it is sufficient to specify a time constant that corresponds to the temperature of the hydraulic oil.

[0129] The judgment threshold output unit 303 includes a threshold correspondence map 303A, and outputs to the comparison calculation unit 308 a judgment threshold based on the command value of the pilot pressure input from the pilot command generation unit 351.

[0130] The threshold correspondence map 303A is a two-dimensional map in which the command value of the pilot pressure and the judgment threshold correspond to each other. The judgment threshold is a positive value and is a threshold for determining whether or not the difference between the command value of the pilot pressure and the actual pilot pressure is abnormal. The correspondence between the command value of the pilot pressure and the judgment threshold is determined according to the embodiment. For example, the judgment threshold may be constant regardless of the command value of the pilot pressure. In addition, the command value of the pilot pressure may have a positive correlation in which the judgment threshold increases as the command value of the pilot pressure increases, or a negative correlation in which the judgment threshold decreases as the command value of the pilot pressure increases. Furthermore, the correspondence between the command value of the pilot pressure and the judgment threshold may be linear or nonlinear. In addition, the judgment threshold according to this embodiment is not limited to a two-dimensional map in which the command value of the pilot pressure corresponds to the command value of the pilot pressure, and may be, for example, a predetermined value set in advance.

[0131] A primary low-pass filter (an example of a calculation unit) 304 calculates and outputs a reference value of the pilot pressure (an example of specific information) based on the command value of the pilot pressure generated by a pilot command generation unit 351, taking into consideration the change in the pilot pressure over time when the command value is followed.

[0132] The primary low-pass filter (an example of a calculation unit) 304 is configured as a filter of a primary delay system that outputs a reference value of the pilot pressure when a command value of the pilot pressure is input. In this embodiment, by providing a filter of a primary delay system corresponding to the hydraulic system, it is possible to improve the accuracy of determining an abnormality.

[0133] The primary low-pass filter (an example of a calculation unit) 304 removes high-frequency components of the time waveform from the input command value of the pilot pressure and outputs a reference value of the pilot pressure. As a result, when a command value with a steep change in the time waveform is input, the primary low-pass filter 304 outputs a reference value of the pilot pressure based on the dull time waveform.

[0134] In addition, in this embodiment, a time constant input from time constant output unit 301 is set in primary low-pass filter 304. In other words, different values ​​of time constants are set in primary low-pass filter 304 depending on the temperature of the hydraulic oil. As a result, primary low-pass filter 304 outputs a reference value of the pilot pressure taking into account the temperature of the hydraulic oil, making it possible to determine an abnormality in proportional valve 31 taking into account the temperature of the hydraulic oil. Since it becomes possible to make a determination taking into account the temperature of the hydraulic oil, it is possible to improve the accuracy of the determination.

[0135] In this embodiment, an example will be described in which the reference value of the pilot pressure is calculated by regarding the hydraulic system as a first-order delay system. However, the controller 30 according to this embodiment is not limited to a method of calculating the reference value of the pilot pressure by regarding the hydraulic system as a first-order delay system, but only needs to be able to output a reference value that takes into account the change in the pilot pressure over time when a sudden operation is performed on the operating device 26.

[0136] For example, when the lever of the operating device 26 is operated slowly, the pilot pressure that is actually detected can follow the command value of the pilot pressure. On the other hand, when the lever of the operating device 26 is operated suddenly, it becomes difficult for the pilot pressure that is actually detected to follow the command value of the pilot pressure.

[0137] For this reason, in this embodiment, a reference value may be output from primary low-pass filter 304 so that the difference between a first command value generated according to a first signal received from operation sensor 29 when a first operation is performed on operation device 26 and a first reference value calculated by primary low-pass filter 304 based on the first command value is greater than the difference between a second command value generated according to a second signal received from operation sensor 29 when a second operation having a smaller operation amount than the first operation is performed and a second reference value calculated by primary low-pass filter 304 based on the second command value. This makes it possible to determine an abnormality using a reference value that takes into account the ability to follow the speed of the lever operation, thereby suppressing erroneous detection.

[0138] The calculator 305 subtracts the pilot pressure detected by the pilot pressure sensor 32 from the reference value of the pilot pressure input from the primary low-pass filter 304, and outputs a deviation indicating the result of the subtraction.

[0139] The positive / negative determination unit 306 determines whether the deviation input from the calculator 305 is positive or negative, and outputs the determination result. In this embodiment, a case where the process described later is performed regardless of whether the deviation is positive or negative will be described, but the process described later may be performed only when the deviation is positive or negative. As a modified example, only when the positive / negative determination unit 306 determines that the deviation is positive in an inspection process during manufacture of the shovel 100, in other words, when the detected pilot pressure is determined to be large relative to a reference value, the abnormality detection unit 300 considers that there is a possibility of an abnormality, and performs the process described later (the process by the absolute value calculation unit 307, the comparison calculation unit 308, the timer 309, the comparison calculation unit 310, and the command output unit 311). In other words, since there is a situation in which no pilot pressure is applied in the inspection process during manufacture, erroneous determination in that situation can be suppressed.

[0140] The result of the determination by the positive / negative determination unit 306 is input to a command output unit 311 via an absolute value calculation unit 307 , a comparison operation unit 308 , a timer 309 , and a comparison operation unit 310 .

[0141] The absolute value calculation section 307 calculates the absolute value of the deviation input from the calculator 305, and outputs the absolute value of the deviation.

[0142] The comparison calculation unit (an example of a determination unit) 308 determines whether or not the absolute value of the deviation input from the absolute value calculation unit 307 is greater than the determination threshold input from the determination threshold output unit 303. The comparison calculation unit 308 according to this embodiment determines whether or not an abnormal state occurs with respect to the proportional valve 31, depending on whether or not the absolute value of the deviation between the reference value and the actual pilot pressure is greater than the determination threshold. In this embodiment, an example of determining whether or not the absolute value of the deviation between the reference value and the actual pilot pressure is greater than the determination threshold will be described. However, this embodiment shows an example of a determination method, and any determination based on the reference value and the actual pilot pressure may be used. In other words, if the determination is made using the reference value, it is possible to perform a determination taking into account a delay occurring in the hydraulic system, so that it is possible to suppress erroneous detection of an abnormality and to quickly detect an abnormality when it actually occurs.

[0143] When the comparison operation unit 308 determines that the absolute value of the deviation is greater than the judgment threshold, it instructs the timer 309 to start counting the elapsed time. When the comparison operation unit 308 determines that the absolute value of the deviation is equal to or less than the judgment threshold, it instructs the timer 309 to end counting the elapsed time.

[0144] In response to a start instruction from comparison calculation unit 308, timer 309 starts counting the elapsed time since it was determined that the absolute value of the deviation is greater than the determination threshold, in other words, since an abnormal state occurred in proportional valve 31. Then, timer 309 outputs the elapsed time to comparison calculation unit 310.

[0145] The timer 309 ends counting the elapsed time in accordance with an instruction to end the count from the comparison operation unit 308. When the timer 309 ends counting the elapsed time, it initializes the count to '0'.

[0146] The comparison calculation unit (an example of a determination unit) 310 determines whether or not the elapsed time input from the timer 309 is greater than the determination time input from the determination time output unit 302. Then, the comparison calculation unit 310 outputs the determination result to the command output unit 311. As described above, in this embodiment, the comparison calculation unit 310 determines an abnormality related to the proportional valve 31 based on the elapsed time during which a state in which the deviation between the reference value of the pilot pressure and the detected pilot pressure is greater than a determination threshold value (an example of a predetermined standard) continues. That is, in this embodiment, since it is determined whether or not an abnormality has occurred based on the elapsed time during which the abnormal state continues, an abnormality related to sticking of the proportional valve 31 can be detected with high accuracy.

[0147] For example, when the comparison calculation unit 310 determines that the elapsed time is greater than the determination time, it outputs to the command output unit 311 a determination result that an abnormality has occurred in the proportional valve 31 .

[0148] As described above, the viscosity of the hydraulic oil changes depending on the temperature of the hydraulic oil. Therefore, the time required for the actual pilot pressure to reach the command value of the pilot pressure changes depending on the temperature of the hydraulic oil. Therefore, the comparison calculation unit 310 according to this embodiment varies the time required to determine an abnormality (determination time) depending on the temperature of the hydraulic oil. Specifically, the determination time output unit 302 outputs a determination time according to the temperature of the hydraulic oil to the comparison calculation unit 310, and the comparison calculation unit 310 performs a determination using the determination time input from the determination time output unit 302. This enables the comparison calculation unit 310 to perform a determination according to the temperature of the hydraulic oil detected by the temperature sensor 34. Therefore, this embodiment can perform a determination taking into account the temperature of the hydraulic oil, thereby improving the accuracy of the determination of an abnormality of the proportional valve 31.

[0149] The command output unit (an example of a control unit) 311 outputs a command according to the input judgment result. For example, when a judgment result indicating that an abnormality has occurred is input, the command output unit 311 outputs a control current indicating that the gate lock control valve 33 capable of supplying hydraulic oil to the proportional valve 31 is to be closed. As another example, when a judgment result indicating that an abnormality has occurred is input, the command output unit 311 outputs information indicating that an abnormality has occurred in the proportional valve 31 to the display device 60. The information indicating that an abnormality has occurred output by the command output unit 311 differs depending on the judgment result of the positive / negative determination unit 306. For example, when the positive / negative determination unit 306 judges that the positive / negative is positive, the command output unit 311 outputs a message indicating that a low pressure abnormality has occurred, in other words, that the proportional valve 31 has been stuck closed. On the other hand, when the positive / negative determination unit 306 judges that the positive / negative is negative, the command output unit 311 outputs a message indicating that a high pressure abnormality has occurred, in other words, that the proportional valve 31 has been stuck open. Further, the output destination of the information indicating the occurrence of an abnormality is not limited to the display device 60, and may be output as a sound. The controller 30 according to this embodiment performs control to close the gate lock control valve 33 arranged upstream of the proportional valve 31 when an abnormality occurs in the proportional valve 31. By closing the gate lock control valve 33, the operation of the excavator 100 can be stopped, thereby improving safety. In this embodiment, the output is made so that the difference between stuck open and stuck closed can be recognized. In other words, the response by a serviceman or the like differs between stuck open and stuck closed, and therefore it is possible to take a response according to the situation, thereby improving safety.

[0150] Next, a description will be given of the determination of an abnormality based on the command value of the pilot pressure by the abnormality detection unit 300 according to this embodiment. Fig. 7 is a diagram illustrating the abnormality determination by the abnormality detection unit 300 according to this embodiment using the reference value of the pilot pressure.

[0151] 7, graph 1701 shows the change in pilot pressure over time. Graph 1701 shows a pilot pressure command value 1711 and a detected pilot pressure 1713. In the example shown in graph 1701, the opening control of proportional valve 31 is performed based on the pilot pressure command value until time t0. Then, at time t0, the proportional valve 31 becomes stuck, and the detected pilot pressure 1713 stops changing.

[0152] Graph 1703 shows an example of a conventionally used first determination method in which a determination is made based on whether or not the difference between a command value for the pilot pressure and a detected pilot pressure is greater than a first threshold value. Graph 1703 shows an example in which a relatively small value is set as the first threshold value.

[0153] For this reason, in the graph 1703, an abnormality can be detected at a relatively early time t2 after the time t0. However, because a relatively small value is set as the first threshold, two false detections 1751 of an abnormality occur even while the proportional valve 31 is operating normally.

[0154] Graph 1704 shows an example of a conventionally used second determination method in which a determination is made based on whether or not the difference between the command value of the pilot pressure and the detected pilot pressure is greater than a second threshold value. Graph 1704 shows an example in which a relatively large value is set as the second threshold value.

[0155] For this reason, in the graph 1704, no erroneous determination occurs before time t0, but an abnormality is detected at time t3, a considerable time after time t0.

[0156] As shown by graphs 1703 and 1704, if the threshold is made small, an abnormality can be detected quickly but the number of erroneous determinations increases, whereas if the threshold is made large, the number of erroneous determinations can be suppressed but the detection of an abnormality becomes slower.

[0157] Therefore, in this embodiment, whether or not there is an abnormality is determined using the reference value output from the primary low-pass filter 304. Graph 1701 shows reference value 1712 output from the primary low-pass filter 304.

[0158] Then, the comparison calculation unit (an example of a determination unit) 308 determines whether or not the absolute value of the deviation between the reference value 1712 and the detected pilot pressure 1713 is greater than the determination threshold value. Thereafter, the comparison calculation unit (an example of a determination unit) 310 determines whether or not an abnormality exists regarding the proportional valve 31 depending on whether or not the elapsed time since the absolute value of the deviation became greater than the determination threshold value is greater than the determination time.

[0159] Graph 1702 shows the case where the determination method according to this embodiment is used, and an abnormality is detected at time t1, which is a short time after time t0.

[0160] The determination method of the present embodiment can detect an abnormality at substantially the same time as the conventionally used first determination method, and can suppress erroneous detection. In addition, the determination method of the present embodiment is common to the conventionally used second determination method in that it can suppress erroneous detection, but it can also improve the speed at which an abnormality is detected.

[0161] Second Embodiment In the above-described embodiment, a case where an operation is performed on the operating device 26 has been described. However, the above-described embodiment is not limited to a case where an operation is performed on the operating device 26. For example, when the shovel 100 can be remotely operated, the same processing as in the above-described embodiment may be performed. Therefore, in the second embodiment, a case where the shovel is remotely operated will be described.

[0162] Therefore, an overview of the remote control system SYS according to the second embodiment will be described with reference to Fig. 8. Fig. 8 is a schematic diagram showing an example of the remote control system SYS according to the second embodiment.

[0163] As shown in Fig. 8, the remote operation system SYS according to the second embodiment includes a shovel 100 and a remote operation room RC. The shovel 100 according to this embodiment has a similar configuration to the above-described embodiments.

[0164] The excavator 100 and the remote control room RC are connected via a communication line NT so as to be able to send and receive data.

[0165] The shovel 100 is capable of wireless communication by using the communication device T1. The shovel 100 is then capable of transmitting and receiving data to and from a device (for example, a remote control room RC) connected to the communication line NT.

[0166] The shovel 100 can then transmit information about the work site to the remote control room RC. This allows the remote control room RC to check the work site in accordance with the information from the shovel 100. Note that in this embodiment, the device that measures the work site is not limited to the shovel 100, and may be another type of device, such as a drone that flies over the work site, a fixed camera, or an imaging device that can be carried by a user.

[0167] For example, an imaging device S6 is provided in the shovel 100. The shovel 100 transmits a captured image indicating the result of capturing an image of the work site by the imaging device S6 to the remote control room RC.

[0168] The remote operation system SYS may include one or more shovels 100. This allows the remote operation system SYS to provide information about the work site to the remote operation room RC through the multiple shovels 100.

[0169] <Example of remote control room configuration> The remote control room RC is equipped with a communication device T2, a remote controller R30, an operation device R26, an operation sensor R29, and a display device D1. Also, the remote control room RC is provided with an operation seat DS where an operator OP who remotely operates the excavator 100 sits.

[0170] The communication device T2 is configured to control communication with the communication device T1 attached to the excavator 100.

[0171] The remote controller (an example of a remote control unit) R30 is a calculation device that executes various calculations. In this embodiment, the remote controller R30 is configured with a microcomputer including a CPU and a memory. The various functions of the remote controller R30 are realized by the CPU executing a program stored in the memory.

[0172] The display device D1 displays a screen based on information transmitted from the shovel 100 so that the operator OP in the remote control room RC can visually confirm the surroundings of the shovel 100. The display device D1 enables the operator to confirm the status of the work site including the surroundings of the shovel 100 even though he is in the remote control room RC.

[0173] The operation device R26 is provided with an operation sensor R29 for detecting the operation content of the operation device R26. The operation sensor R29 is, for example, an inclination sensor that detects the inclination angle of the operation lever, or an angle sensor that detects the swing angle of the operation lever around the swing axis. The operation sensor R29 may be composed of other sensors such as a pressure sensor, a current sensor, a voltage sensor, or a distance sensor. The operation sensor R29 outputs information on the detected operation content of the operation device R26 to the remote controller R30. The remote controller R30 generates an operation signal based on the received information and transmits the generated operation signal to the excavator 100. The operation sensor R29 may be configured to generate an operation signal. In this case, the operation sensor R29 may output the operation signal to the communication device T2 without passing through the remote controller R30. This allows remote operation of the excavator 100 to be realized from the remote operation room RC.

[0174] Then, the communication device T1 of the shovel 100 receives an operation signal from the communication device T2 of the remote controller R30. Then, the controller 30 of the shovel 100 performs drive control of the shovel 100 based on the received control signal.

[0175] In the controller 30 of the excavator 100, the pilot command generating unit 351 generates a command value for the proportional valve 31 according to the received operation signal. The primary low-pass filter 304 calculates a reference value for the pilot pressure from the command value for the proportional valve 31 and outputs it. Then, the calculator 305 calculates the deviation between the reference value and the detected pilot pressure. The positive / negative determination unit 306 determines whether the deviation is positive or negative. The absolute value calculation unit 307 calculates the absolute value of the deviation. Then, the comparison calculation unit 308 determines whether the absolute value of the deviation between the reference value for the pilot pressure and the detected pilot pressure is greater than the determination threshold value. The subsequent control is the same as in the above-mentioned embodiment.

[0176] <effect> In the above-described embodiment, by determining an abnormality related to the proportional valve 31 according to the reference value of the pilot pressure and the detected pilot pressure, it is possible to suppress erroneous detection and improve the speed until an abnormality is detected. In the above-described embodiment, by achieving both suppression of erroneous detection and improvement of the speed until an abnormality is detected, it is possible to improve the accuracy of detecting an abnormality. Therefore, in the above-described embodiment, it is possible to improve safety.

[0177] Moreover, in the above-described embodiment, the frequency with which the proportional valve 31 is determined to be abnormal when the proportional valve 31 is normal is suppressed. Therefore, while the shovel 100 is performing work, it is possible to suppress the suspension of work due to a determination that an abnormality has occurred, and therefore it is possible to suppress a decrease in work efficiency.

[0178] Although the embodiment of the shovel and the remote control system for the shovel according to the present invention has been described above, the present invention is not limited to the above embodiment. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. Naturally, these also fall within the technical scope of the present invention. [Explanation of symbols]

[0179] 100 Shovel 1 Undercarriage 2 Swivel mechanism 3. Upper rotating body 4. Boom 5 Arm 6 Bucket 7 Boom cylinder 8 Arm Cylinder 9 Bucket Cylinder 17 Control valve unit S1 Boom Angle Sensor S2 Arm Angle Sensor S3 Bucket Angle Sensor S5 Rotation Angle Sensor S6 imaging device S7R, S7B, S8R, S8B, S9R, S9B Cylinder pressure sensor PS Positioning Device T1 Communications Equipment 26 Operating device 29 Operation Sensor 30 Controller 31 Proportional valve 32 Pilot pressure sensor 33 Gate lock control valve 34 Temperature Sensor 300 Anomaly detection unit 301 Time constant output section 302 Judgment time output unit 303 Judgment threshold output unit 304 First-order low-pass filter 305 Arithmetic unit 306 Positive / negative judgment section 307 Absolute value calculation section 308 Comparison Operation Section 309 Timer 310 Comparison operation section 311 Command output section 351 Pilot command generator 352 Current generation section SYS Remote Control System RC Remote Control Room T2 Communication Equipment R30 Remote Controller D1 display device

Claims

1. A lower running body; An upper rotating body that can rotate relative to the lower traveling body; A hydraulic pump; a hydraulic actuator driven by hydraulic oil discharged from the hydraulic pump; a directional control valve for switching a supply path of the hydraulic oil from the hydraulic pump to the hydraulic actuator; An electric operating device; a proportional valve capable of adjusting a pilot pressure of the hydraulic oil supplied to the directional control valve in order to switch the supply path; A first detection unit that detects the pilot pressure; A control device, The control device includes: A calculation unit that calculates a reference value of the pilot pressure based on a signal from the electric operating device, taking into consideration a time-series change in the pilot pressure in accordance with the signal; A determination unit that determines an abnormality related to the proportional valve according to a reference value of the pilot pressure and the detected pilot pressure. Shovel.

2. The calculation unit is configured as a first-order delay filter that outputs the reference value when a command value of the pilot pressure generated based on the signal from the electric operating device is input. The shovel according to claim 1.

3. A second detection unit that detects the temperature of the hydraulic oil is further provided. The calculation unit varies the time constant of the filter depending on the detected temperature of the hydraulic oil. The shovel according to claim 2.

4. a difference between a first command value of the pilot pressure generated in accordance with a first signal received when a first operation is performed on the electric operation device and a first reference value calculated from the first command value is greater than a difference between a second command value of the pilot pressure generated in accordance with a second signal received when a second operation having a smaller operation amount than the first operation is performed and a second reference value calculated from the second command value; A shovel according to any one of claims 1 to 3.

5. The determination unit determines an abnormality related to the proportional valve based on a time during which a state in which a difference between the reference value and the detected pilot pressure is greater than a predetermined reference value continues. The shovel according to claim 1 or 2.

6. A second detection unit that detects the temperature of the hydraulic oil is further provided. The determination unit varies a time required to determine that an abnormality has occurred in the proportional valve depending on the detected temperature of the hydraulic oil. The shovel according to claim 5.

7. and a control unit that controls a valve capable of supplying the hydraulic oil to the proportional valve to be closed when the determination unit determines that an abnormality has occurred in the proportional valve. The shovel according to claim 1 or 2.

8. A remote control device including an electric operation device and a first communication device that transmits a signal received by the electric operation device; an excavator comprising: a lower traveling body; an upper rotating body capable of rotating relative to the lower traveling body; a hydraulic pump; a hydraulic actuator driven by hydraulic oil discharged from the hydraulic pump; a directional control valve that switches a supply path of the hydraulic oil from the hydraulic pump to the hydraulic actuator; a second communication device that receives the signal; a proportional valve that can adjust a pilot pressure of the hydraulic oil supplied to the directional control valve in order to switch the supply path; a first detection unit that detects the pilot pressure; and a control device; The control device includes: A calculation unit that calculates a reference value of the pilot pressure based on the signal, taking into consideration a time-series change in the pilot pressure in accordance with the signal; A determination unit that determines an abnormality related to the proportional valve according to a reference value of the pilot pressure and the detected pilot pressure. Remote control system for excavators.

Images