JP2021073401A - Shovel, and system for shovel - Google Patents

Abstract

To provide a shovel capable of recognizing a current shape of the ground of a work object.SOLUTION: A shovel in an embodiment of this invention includes an undercarriage 1, a revolving super structure 3 mounted on the undercarriage 1, an excavation attachment attached to the revolving super structure 3, an attitude detecting unit M3 for detecting an attitude of the excavation attachment, and an external arithmetic unit 30E. The external arithmetic unit 30E acquires information regarding a current shape of the ground of an excavation object based on transition of the attitude of the excavation attachment detected by the attitude detecting unit M3. The acquired information regarding the current shape of the ground of the excavation object includes information regarding the shape of the ground varied by earth removal.SELECTED DRAWING: Figure 4

Description

The present invention relates to an excavator with an attachment.

A shovel having a variable throttle that increases or decreases the flow rate of hydraulic oil flowing out from the rod-side oil chamber of the arm cylinder when the arm is closed is known (see Patent Document 1). This excavator monitors the pressure in the bottom oil chamber of the arm cylinder to control the variable throttle. If the pressure in the bottom oil chamber is less than the specified value, it can be determined that the bucket is not in contact with the ground and the excavation attachment is operating in the air, and the hydraulic oil that flows through the variable throttle so that the arm does not fall under its own weight. This is because it can be determined that the flow rate of If the pressure in the bottom oil chamber is equal to or higher than a predetermined value, it can be determined that the bucket is in contact with the ground, and the flow rate of hydraulic oil flowing through the variable throttle is adjusted so that unnecessary pressure loss does not occur at the variable throttle. This is because it can be judged that it should be increased.

Japanese Unexamined Patent Publication No. 2010-230061

However, the excavator described above determines whether to reduce or increase the flow rate of hydraulic oil flowing through the variable throttle only after detecting the contact between the bucket and the ground based on the pressure in the oil chamber on the bottom side of the arm cylinder. Can not. As a result, the flow rate cannot be increased at the start of excavation, causing unnecessary pressure loss at the variable throttle and reducing the working efficiency of the excavator. This is because the current shape of the ground to be excavated is not known, so it is not possible to determine in advance when the bucket will come into contact with the ground.

In view of the above, it is desired to provide an excavator capable of recognizing the current shape of the ground to be worked on.

The excavator according to the embodiment of the present invention includes a lower traveling body, an upper rotating body mounted on the lower traveling body, an attachment attached to the upper rotating body, a posture detecting device for detecting the posture of the attachment, and a posture detecting device. A shovel including a control device, wherein the control device acquires information on the current shape of the ground to be worked on based on the transition of the posture of the attachment detected by the posture detection device, and the acquired work. The attachment is controlled based on information about the current shape of the target ground.

By the means described above, an excavator capable of recognizing the current shape of the ground to be worked on is provided.

It is a side view of the excavator which concerns on embodiment of this invention. It is a side view of the excavator which shows an example of the output contents of the various sensors constituting the posture detection device mounted on the excavator of FIG. It is a figure which shows the configuration example of the basic system mounted on the excavator of FIG. It is a functional block diagram which shows the configuration example of an external arithmetic unit. It is a conceptual diagram of the information about the current shape of the excavation target ground acquired by the ground shape information acquisition part. It is a flowchart which shows an example of the flow of the ground shape acquisition process after excretion of soil. It is a figure which shows the relationship between a bucket angle and a sediment discharge rate. It is a conceptual diagram of the information about the ground shape after the soil removal operation. It is a figure which shows the structural example of the drive system mounted on the excavator of FIG. It is a figure which shows the structural example of the regeneration oil passage and the regeneration release valve. It is a flowchart which shows the flow of the opening area adjustment processing. It is a figure which shows the time transition of various parameters when the controller adjusts the opening area of a regeneration release valve. It is a figure which shows the relationship between the depth of the excavation target ground, and the reference plane. It is a figure which shows the relationship between a bucket angle and an excavation reaction force. It is a flowchart which shows the flow of the posture automatic adjustment processing. It is a functional block diagram which shows the configuration example of an external arithmetic unit. It is a functional block diagram which shows the configuration example of an external arithmetic unit. It is a functional block diagram which shows the configuration example of an external arithmetic unit. It is a functional block diagram which shows the configuration example of an external arithmetic unit.

First, the excavator as a construction machine according to the embodiment of the present invention will be described with reference to FIG. Note that FIG. 1 is a side view of the excavator according to the embodiment of the present invention. The upper swivel body 3 is mounted on the lower traveling body 1 of the shovel shown in FIG. 1 via the swivel mechanism 2. A boom 4 is attached to the upper swing body 3. An arm 5 is attached to the tip of the boom 4, and a bucket 6 is attached to the tip of the arm 5. The boom 4, arm 5, and bucket 6 as working elements constitute an excavation attachment, which is an example of an attachment. The attachment may be another attachment such as a floor moat attachment, a leveling attachment, or a dredging attachment. Further, the boom 4, the arm 5, and the bucket 6 are hydraulically driven by the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9, respectively. Further, the upper swing body 3 is provided with a cabin 10, and a power source such as an engine 11 is mounted on the upper swing body 3. Further, a communication device M1, a positioning device M2, a posture detection device M3, and a cylinder pressure detection device M4 are attached to the upper swing body 3.

The communication device M1 is a device that controls communication between the shovel and the outside. In this embodiment, the communication device M1 controls wireless communication between the GNSS (Global Navigation Satellite System) survey system and the excavator. Specifically, the communication device M1 acquires topographical information on the work site when the excavator work is started, for example, once a day. The GNSS surveying system employs, for example, a network-type RTK-GNSS positioning method.

The positioning device M2 is a device that measures the position and orientation of the excavator. In this embodiment, the positioning device M2 is a GNSS receiver incorporating an electronic compass, measures the latitude, longitude, and altitude of the position where the excavator exists, and measures the orientation of the excavator.

The posture detection device M3 is a device that detects the posture of the attachment. In this embodiment, the posture detection device M3 is a device that detects the posture of the excavation attachment.

The cylinder pressure detection device M4 is a device that detects the pressure of the hydraulic oil in the hydraulic cylinder. In this embodiment, the cylinder pressure detecting device M4 includes a boom bottom pressure sensor that detects the pressure in the oil chamber on the bottom side of the boom cylinder 7 (hereinafter, referred to as “boom bottom pressure”).

FIG. 2 is a side view of the excavator showing an example of the output contents of various sensors constituting the posture detection device M3 mounted on the excavator of FIG. Specifically, the posture detection device M3 includes a boom angle sensor M3a, an arm angle sensor M3b, a bucket angle sensor M3c, and a vehicle body inclination sensor M3d.

The boom angle sensor M3a is a sensor that acquires the boom angle θ1, for example, a rotation angle sensor that detects the rotation angle of the boom foot pin, a stroke sensor that detects the stroke amount of the boom cylinder 7, and a tilt angle of the boom 4. Includes tilt (acceleration) sensors and the like. The boom angle θ1 is an angle with respect to the horizontal line of the line segment connecting the boom foot pin position P1 and the arm connecting pin position P2 in the XZ plane.

The arm angle sensor M3b is a sensor that acquires the arm angle θ2. For example, a rotation angle sensor that detects the rotation angle of the arm connecting pin, a stroke sensor that detects the stroke amount of the arm cylinder 8, and an inclination angle of the arm 5 are detected. Includes tilt (acceleration) sensors and the like. The arm angle θ2 is an angle with respect to the horizontal line of the line segment connecting the arm connecting pin position P2 and the bucket connecting pin position P3 in the XZ plane.

The bucket angle sensor M3c is a sensor that acquires the bucket angle θ3. For example, a rotation angle sensor that detects the rotation angle of the bucket connecting pin, a stroke sensor that detects the stroke amount of the bucket cylinder 9, and a tilt angle of the bucket 6 are detected. Includes tilt (acceleration) sensors and the like. The bucket angle θ3 is an angle with respect to the horizontal line of the line segment connecting the bucket connecting pin position P3 and the bucket toe position P4 in the XZ plane.

The vehicle body tilt sensor M3d is a sensor that acquires an inclination angle θ4 around the Y-axis of the excavator and an inclination angle θ5 (not shown) around the X-axis of the excavator. Including. The XY plane in FIG. 2 is a horizontal plane.

Next, the basic system of the excavator will be described with reference to FIG. The basic system of the excavator mainly includes an engine 11, a main pump 14, a pilot pump 15, a control valve 17, an operating device 26, a controller 30, an engine control device (ECU) 74, and the like.

The engine 11 is a drive source for a shovel, for example, a diesel engine that operates so as to maintain a predetermined rotation speed. The output shaft of the engine 11 is connected to the input shafts of the main pump 14 and the pilot pump 15.

The main pump 14 is a hydraulic pump that supplies hydraulic oil to the control valve 17 via a high-pressure hydraulic line 16, and is, for example, a swash plate type variable displacement hydraulic pump. The main pump 14 can adjust the stroke length of the piston by changing the angle (tilt angle) of the swash plate, and can change the discharge flow rate, that is, the pump output. The swash plate of the main pump 14 is controlled by the regulator 14a. The regulator 14a changes the tilt angle of the swash plate in response to a change in the control current with respect to the electromagnetic proportional valve (not shown). For example, by increasing the control current, the regulator 14a increases the tilt angle of the swash plate and increases the discharge flow rate of the main pump 14. Further, by reducing the control current, the regulator 14a reduces the tilt angle of the swash plate and reduces the discharge flow rate of the main pump 14.

The pilot pump 15 is a hydraulic pump for supplying hydraulic oil to various hydraulic control devices via the pilot line 25, and is, for example, a fixed-capacity hydraulic pump.

The control valve 17 is a hydraulic control valve that controls a hydraulic system in a forestry machine. The control valve 17 has, for example, a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, and a traveling hydraulic motor 1A (for the left) according to a pressure change according to the operating direction and operating amount of the levers or pedals 26A to 26C described later. , The running hydraulic motor 1B (for the right), and one or more of the turning hydraulic motors 2A are selectively supplied with the hydraulic oil supplied from the main pump 14 through the high-pressure hydraulic line 16. In the following description, the boom cylinder 7, arm cylinder 8, bucket cylinder 9, traveling hydraulic motor 1A (for left), traveling hydraulic motor 1B (for right), and turning hydraulic motor 2A are collectively referred to as "flood control". It is called "actuator".

The operating device 26 is a device used by the operator to operate the hydraulic actuator. The operating device 26 supplies the hydraulic oil supplied from the pilot pump 15 via the pilot line 25 to the pilot port of the flow control valve corresponding to each of the hydraulic actuators through the pilot line 25a. The pressure of the hydraulic oil supplied to each of the pilot ports is a pressure corresponding to the operation direction and the operation amount of the levers or pedals 26A to 26C corresponding to each of the hydraulic actuators.

The controller 30 is a control device for controlling the excavator, and is composed of, for example, a computer equipped with a CPU, RAM, ROM, and the like. The CPU of the controller 30 reads a program corresponding to the operation and function of the excavator from the ROM and executes the program while loading the program into the RAM, thereby executing the processing corresponding to each of the programs.

The controller 30 controls the discharge flow rate of the main pump 14. For example, the control current is changed according to the negative control pressure of the negative control valve (not shown), and the discharge flow rate of the main pump 14 is controlled via the regulator 14a.

The engine control device (ECU) 74 is a device that controls the engine 11. For example, based on a command from the controller 30, the engine 11 determines the fuel injection amount for controlling the engine speed according to the engine speed (mode) set by the operator by the engine speed adjustment dial 75 described later. Output to.

The engine speed adjustment dial 75 is a dial for adjusting the engine speed provided in the cabin 10, and in the present embodiment, the engine speed can be switched in five stages. That is, the engine speed adjustment dial 75 enables the engine speed to be switched in five stages of Rmax, R4, R3, R2 and R1. Note that FIG. 3 shows a state in which R4 is selected by the engine speed adjustment dial 75.

Rmax is the maximum number of revolutions of the engine 11 and is selected when it is desired to prioritize the amount of work. R4 is the second highest engine speed and is selected when it is desired to achieve both work load and fuel efficiency. R3 and R2 are the third and fourth highest engine speeds, and are selected when it is desired to operate the excavator with low noise while giving priority to fuel efficiency. R1 is the lowest engine speed (idling speed), and is the engine speed in the idling mode selected when the engine 11 is desired to be in the idling state. For example, Rmax (maximum rotation speed) may be set to 2000 rpm, R1 (idling rotation speed) may be set to 1000 rpm, and R4 (1750 rpm), R3 (1500 rpm), and R2 (1250 rpm) may be set in multiple steps in between. Then, the engine 11 is constantly controlled at the engine speed set by the engine speed adjustment dial 75. Here, an example of adjusting the engine speed in five stages by the engine speed adjustment dial 75 is shown, but the number of stages is not limited to five and may be any number of stages.

Further, on the excavator, an image display device 40 is arranged in the vicinity of the driver's seat of the cabin 10 in order to assist the driver in driving. The driver can input information and commands to the controller 30 by using the input unit 42 of the image display device 40. In addition, information can be provided to the driver by displaying the operating status and control information of the excavator on the image display unit 41 of the image display device 40.

The image display device 40 includes an image display unit 41 and an input unit 42. The image display device 40 is fixed to the console in the driver's seat. Generally, the boom 4 is arranged on the right side when viewed from the driver seated in the driver's seat, and the driver operates the excavator while visually recognizing the arm 5 and the bucket 6 attached to the tip of the boom 4. There are many. The frame on the right front side of the cabin 10 is a portion that obstructs the driver's field of vision, but in the present embodiment, the image display device 40 is provided using this portion. As a result, the image display device 40 is arranged in the portion that originally obstructed the field of view, so that the image display device 40 itself does not significantly obstruct the driver's field of vision. Although it depends on the width of the frame, the image display device 40 may be configured such that the image display unit 41 is vertically long so that the entire image display device 40 is within the width of the frame.

In the present embodiment, the image display device 40 is connected to the controller 30 via a communication network such as CAN or LIN. The image display device 40 may be connected to the controller 30 via a dedicated line.

Further, the image display device 40 includes a conversion processing unit 40a that generates an image to be displayed on the image display unit 41. In the present embodiment, the conversion processing unit 40a generates a camera image to be displayed on the image display unit 41 based on the output of the image pickup apparatus M5. Therefore, the image pickup device M5 is connected to the image display device 40 via, for example, a dedicated line. Further, the conversion processing unit 40a generates an image to be displayed on the image display unit 41 based on the output of the controller 30.

The conversion processing unit 40a may be realized not as a function of the image display device 40 but as a function of the controller 30. In this case, the image pickup device M5 is connected to the controller 30 instead of the image display device 40.

Further, the image display device 40 includes a switch panel as an input unit 42. A switch panel is a panel that includes various hardware switches. In this embodiment, the switch panel includes a light switch 42a, a wiper switch 42b, and a window washer switch 42c as hardware buttons. The light switch 42a is a switch for switching on / off of a light attached to the outside of the cabin 10. The wiper switch 42b is a switch for switching the operation / stop of the wiper. Further, the window washer switch 42c is a switch for injecting the window washer liquid.

Further, the image display device 40 operates by receiving electric power from the storage battery 70. The storage battery 70 is charged with the electric power generated by the alternator 11a (generator) of the engine 11. The electric power of the storage battery 70 is also supplied to the electrical components 72 of the excavator other than the controller 30 and the image display device 40. Further, the starter 11b of the engine 11 is driven by the electric power from the storage battery 70 to start the engine 11.

As described above, the engine 11 is controlled by the engine control unit (ECU) 74. From the ECU 74, various data indicating the state of the engine 11 (for example, data indicating the cooling water temperature (physical quantity) detected by the water temperature sensor 11c) are constantly transmitted to the controller 30. Therefore, the controller 30 can store this data in the temporary storage unit (memory) 30a and transmit it to the image display device 40 when necessary.

Further, various data are supplied to the controller 30 as follows, and are stored in the temporary storage unit 30a of the controller 30.

First, data indicating the tilt angle of the swash plate is supplied to the controller 30 from the regulator 14a of the main pump 14 which is a variable displacement hydraulic pump. Further, data indicating the discharge pressure of the main pump 14 is sent from the discharge pressure sensor 14b to the controller 30. These data (data representing physical quantities) are stored in the temporary storage unit 30a. Further, an oil temperature sensor 14c is provided in the pipeline between the tank in which the hydraulic oil sucked by the main pump 14 is stored and the main pump 14, and data representing the temperature of the hydraulic oil flowing through the pipeline. Is supplied from the oil temperature sensor 14c to the controller 30.

Further, when the lever or pedals 26A to 26C are operated, the pilot pressure sent to the control valve 17 through the pilot line 25a is detected by the oil pressure sensors 15a and 15b, and data indicating the detected pilot pressure is supplied to the controller 30. To.

Further, from the engine speed adjustment dial 75, data indicating the setting state of the engine speed is constantly transmitted to the controller 30.

The external arithmetic unit 30E performs various calculations based on the outputs of the communication device M1, the positioning device M2, the attitude detection device M3, the cylinder pressure detection device M4, the image pickup device M5, and the like, and outputs the calculation results to the controller 30. It is a device. In this embodiment, the external arithmetic unit 30E operates by receiving power supplied from the storage battery 70.

Next, the function of the external arithmetic unit 30E will be described with reference to FIG. Note that FIG. 4 is a functional block diagram showing a configuration example of the external arithmetic unit 30E. In this embodiment, the external arithmetic unit 30E receives the outputs of the communication device M1, the positioning device M2, the posture detection device M3, and the cylinder pressure detection device M4, executes various calculations, and outputs the calculation results to the controller 30. To do. The controller 30 outputs, for example, a control command according to the calculation result to the control valve E1. The control valve E1 is a valve for controlling the movement of the attachment, and is, for example, a regeneration release valve 50, a pressure reducing valve for adjusting the pilot pressure, a relief valve, and the like.

Specifically, the external arithmetic unit 30E mainly includes a terrain database update unit 31, a position coordinate update unit 32, a ground shape information acquisition unit 33, and a ground contact determination unit 34.

The terrain database update unit 31 is a functional element that updates the terrain database that systematically stores the terrain information of the work site so that it can be referred to. In this embodiment, the terrain database update unit 31 updates the terrain database by acquiring the terrain information of the work site through the communication device M1 when the excavator is started, for example. The terrain database is stored in a non-volatile memory or the like. Further, the topographical information of the work site is described by, for example, a three-dimensional topographical model based on the world positioning system.

The position coordinate updating unit 32 is a functional element that updates the coordinates and the direction representing the current position of the shovel. In this embodiment, the position coordinate updating unit 32 acquires the position coordinates and orientation of the excavator in the world positioning system based on the output of the positioning device M2, and the coordinates representing the current position of the excavator stored in the non-volatile memory or the like. Update the orientation data.

The ground shape information acquisition unit 33 is a functional element that acquires information on the current shape of the ground to be worked on. In this embodiment, the ground shape information acquisition unit 33 detects the terrain information updated by the terrain database update unit 31, the coordinates and directions representing the current position of the excavator updated by the position coordinate update unit 32, and the attitude detection device M3. Information on the current shape of the excavation target ground is acquired based on the past transition of the posture of the excavation attachment and the boom bottom pressure detected by the cylinder pressure detection device M4.

Here, with reference to FIG. 5, a process in which the ground shape information acquisition unit 33 acquires information regarding the ground shape after the excavation operation will be described. FIG. 5 is a conceptual diagram of information regarding the ground shape after the excavation operation. The plurality of bucket shapes shown by the broken lines in FIG. 5 represent the loci of the bucket 6 during the previous excavation operation. The locus of the bucket 6 is derived from the transition of the posture of the excavation attachment detected in the past by the posture detection device M3. The thick solid line in FIG. 5 represents the current cross-sectional shape of the excavation target ground grasped by the ground shape information acquisition unit 33, and the thick dotted line represents the previous excavation operation grasped by the ground shape information acquisition unit 33. Represents the cross-sectional shape of the excavated ground before the excavation. That is, the ground shape information acquisition unit 33 removes the portion corresponding to the space passed by the bucket 6 during the previous excavation operation from the shape of the excavation target ground before the previous excavation operation is performed, thereby removing the excavation target ground. Derives the current shape of. In this way, the ground shape information acquisition unit 33 can estimate the ground shape after the excavation operation. Further, each block extending in the Z-axis direction shown by the alternate long and short dash line in FIG. 5 represents each element of the three-dimensional terrain model. Each element is represented by, for example, a model having an upper surface of a unit area parallel to the XY plane and an infinite length in the −Z direction. The three-dimensional terrain model may be represented by a three-dimensional mesh model.

Next, with reference to FIGS. 6 to 8, a process for the ground shape information acquisition unit 33 to acquire information regarding the ground shape after the soil removal operation (hereinafter, referred to as “ground shape acquisition process after soil removal”) will be described. To do. FIG. 6 is a flowchart showing an example of the flow of the ground shape acquisition process after soil removal. The ground shape information acquisition unit 33 executes the ground shape acquisition process after soil removal when the soil removal operation is performed. For example, the ground shape information acquisition unit 33 executes the ground shape acquisition process after excavation when the bucket opening operation is performed after the excavation operation.

First, the ground shape information acquisition unit 33 estimates the sediment load (step S1). In this embodiment, the ground shape information acquisition unit 33 estimates the sediment load amount based on the attitude of the excavation attachment detected by the attitude detection device M3 and the boom bottom pressure detected by the cylinder pressure detection device M4. The earth and sand load is the amount of earth and sand loaded on the bucket 6 by the excavation operation, and is calculated as, for example, the volume of earth and sand loaded on the bucket 6. In addition, the earth and sand load capacity is limited by a predetermined maximum load capacity.

For example, the ground shape information acquisition unit 33 refers to the boom bottom pressure reference table to acquire the unloaded boom bottom pressure corresponding to the current posture of the excavation attachment. The boom bottom pressure when not loaded means the boom bottom pressure when the bucket 6 is not loaded with earth and sand. The boom bottom pressure table is a reference table stored in advance in a ROM or the like, and is generated based on the analysis of actual measurement data. Specifically, the boom bottom pressure table stores the boom bottom pressure when not loaded in association with the posture of the attachment detected by the posture detection device M3. Then, the weight of the earth and sand loaded on the bucket 6 is estimated based on the difference between the current boom bottom pressure and the unloaded boom bottom pressure. Then, the volume of the earth and sand loaded in the bucket 6 is estimated from the estimated weight of the earth and sand and the earth and sand characteristics (density, viscosity, etc.) input in advance.

Further, the ground shape information acquisition unit 33 may estimate the sediment load amount based on the change in the ground shape.

After that, the ground shape information acquisition unit 33 calculates the amount of earth and sand discharged (step S2). In this embodiment, the ground shape information acquisition unit 33 calculates the sediment discharge amount based on the sediment load amount and the sediment discharge rate. Specifically, the ground shape information acquisition unit 33 calculates the sediment discharge amount by multiplying the sediment load amount by the sediment discharge rate.

The earth and sand discharge amount is the amount of earth and sand discharged from the bucket 6 by the earth and sand discharge operation, and is calculated by multiplying the earth and sand load amount by the earth and sand discharge rate. The amount of earth and sand discharged is calculated as, for example, the volume of earth and sand discharged by the bucket 6 in the same manner as the amount of earth and sand loaded.

The sediment discharge rate is the ratio of the sediment discharge amount to the sediment load capacity, and is determined based on the transition of the attachment posture, the transition of the operation speed, the sediment characteristics, and the like during the sediment discharge operation. In this embodiment, the ground shape information acquisition unit 33 determines the sediment discharge rate with reference to the sediment discharge rate table. The earth and sand discharge rate table is a reference table stored in advance in ROM or the like, and is generated based on the analysis of actual measurement data. Specifically, the sediment discharge rate table stores the sediment discharge rate in association with the bucket angle during the soil discharge operation detected by the attitude detection device M3.

FIG. 7 is a diagram showing the relationship between the bucket angle θ3 and the sediment discharge rate. Specifically, FIG. 7A shows the posture of the bucket 6 when the bucket angle is 30 ° and the posture of the bucket 6 when the bucket angle is 180 °. Further, FIG. 7B shows the transition of the sediment discharge rate with respect to the bucket angle θ3. As shown in FIG. 7B, the sediment discharge rate is set to 0 [%] when the bucket angle θ3 is approximately 150 degrees or more. That is, the ground shape information acquisition unit 33 estimates that if the bucket angle θ3 is approximately 150 degrees or more, the earth and sand in the bucket 6 has not yet been discharged. On the other hand, the sediment discharge rate increases as the bucket angle θ3 falls below about 150 degrees, and reaches 100 [%] when the bucket angle θ3 becomes about 50 degrees or less. That is, the ground shape information acquisition unit 33 estimates that if the bucket angle θ3 is approximately 50 degrees or less, all the earth and sand in the bucket 6 has been discharged.

After that, the ground shape information acquisition unit 33 estimates the ground shape after the soil removal operation (step S3). In this embodiment, the ground shape information acquisition unit 33 determines the amount of earth and sand discharged, the shape of the ground before the latest soil discharge operation, the height of the bucket 6 with respect to the ground during the soil discharge operation, and the time of the soil discharge operation. The ground shape after the soil removal operation is estimated based on the transition of the posture of the attachment, the transition of the operation speed, the sediment characteristics, and the like.

FIG. 8 is a conceptual diagram of information regarding the ground shape after the soil removal operation. FIG. 8A is a diagram showing the positional relationship between the excavated earth and sand and the excavator, and the reference point RP is the center point of the bucket 6 when the earth excavation operation is started on the horizontal plane where the excavator is located. It is a point obtained by projecting. The start of the soil removal operation is, for example, the start of the bucket opening operation. Further, the shape shown by the broken line in FIG. 8A indicates the shape of the portion of the ground shape after the soil removal operation that has been updated by the latest soil removal operation (hereinafter, referred to as “updated partial shape”). In the following, the condition of the soil discharge operation (including, for example, the amount of earth and sand discharged) that brought about the updated partial shape shown by the broken line in FIG. 8 (A) is referred to as the “standard soil discharge condition”.

Further, each of FIGS. 8 (B1) to 8 (B6) shows various updated partial shapes after the soil draining operation caused by the difference in the conditions of the soil discharging operation, and the updated partial shapes shown by the broken lines in each figure are shown. , Corresponds to the updated partial shape shown by the broken line in FIG. 8 (A).

Specifically, the renewal partial shape shown by the thick solid line in FIG. 8 (B1) corresponds to the renewal partial shape when the amount of earth and sand discharged is larger than that under the standard soil discharge condition. In this way, the renewed partial shape is determined so that the larger the amount of sediment discharged, the larger the shape.

In addition, the renewal part shape shown by the thick solid line in FIG. 8 (B2) is the renewal part when the ground shape before the latest soil discharge operation is raised at the reference point RP compared to the reference soil discharge condition. Corresponds to the shape. In this way, the renewed partial shape is determined according to the size (height) of the raised portion of the ground shape before the latest soil removal operation is performed.

In addition, the renewal part shape shown by the thick solid line in FIG. 8 (B3) is the renewal part when the ground shape before the latest soil discharge operation is depressed at the reference point RP than in the reference soil discharge condition. Corresponds to the shape. In this way, the renewed partial shape is determined according to the size (depth) of the depressed portion of the ground shape before the latest soil removal operation is performed.

Further, the updated partial shape shown by the thick solid line in FIG. 8 (B4) corresponds to the updated partial shape when the height of the bucket 6 with respect to the reference point RP during the latest soil discharge operation is higher than that under the reference soil discharge condition. To do. In this way, the shape of the renewed portion is determined so that the higher the height of the bucket 6 during the most recent soil removal operation, the lower the height and the more it spreads to the surroundings.

Further, the renewal partial shape shown by the thick solid line in FIG. 8 (B5) corresponds to the renewal partial shape when the viscosity of the soil discharged by the latest soil discharge operation is lower than that under the standard soil discharge condition. In this way, the renewed partial shape is determined so that the lower the viscosity of the soil discharged in the latest soil discharge operation, the lower the viscosity and the more it spreads to the surroundings.

Further, the renewal partial shape shown by the thick solid line in FIG. 8 (B6) corresponds to the renewal partial shape when the operation speed (opening speed) of the bucket 6 during the latest soil discharge operation is faster than that under the standard soil discharge condition. To do. In this way, the renewal partial shape is determined so that the faster the opening speed of the bucket 6 during the latest soil removal operation, the more biased the bucket 6 is in the opening direction with respect to the reference point RP.

Further, in this embodiment, the ground shape information acquisition unit 33 determines the updated partial shape with reference to the updated partial shape table. The updated partial shape table is a reference table stored in advance in a ROM or the like, and is generated based on the analysis of actual measurement data. Specifically, the updated partial shape table shows the amount of earth and sand discharged, the shape of the ground before the latest earth removal operation, the height of the bucket 6 during the earth removal operation, and the posture of the attachment during the earth removal operation. The updated partial shape is memorized in relation to the transition of the movement speed, the transition of the operation speed, the sediment characteristics, and the like.

In this way, the ground shape information acquisition unit 33 can estimate the ground shape after the soil removal operation. Therefore, the ground shape information acquisition unit 33 can acquire not only information on the ground shape after the excavation operation but also information on the ground shape after the soil removal operation. That is, the ground shape information acquisition unit 33 can more accurately grasp the shape of the excavation target ground before the excavation operation is performed. The information acquired in this way is displayed on the display device 40. Further, it may be transmitted to a management device that manages the operating status of a plurality of excavators via the communication device M1. Then, the management device may display the received information.

The ground contact determination unit 34 is a functional element that determines whether the attachment is in contact with the ground and controls the attachment. In this embodiment, the ground contact determination unit 34 determines whether the excavation attachment is in contact with the ground based on the information regarding the current shape of the excavation target ground acquired by the ground shape information acquisition unit 33, and controls the excavation attachment. To do.

Specifically, the ground contact determination unit 34 excavates based on the current attitude of the excavation attachment detected by the attitude detection device M3 and the information on the current shape of the excavation target ground acquired by the ground shape information acquisition unit 33. Judge the condition. For example, the ground contact determination unit 34 determines whether the toe of the bucket 6 is in contact with the ground to be excavated. Then, when it is determined that the toe of the bucket 6 is in contact with the ground to be excavated, the ground contact determination unit 34 outputs the determination result to the controller 30. Upon receiving the determination result, the controller 30 outputs a control command to the regeneration release valve 50 as the control valve E1 to increase the opening area thereof. The ground contact determination unit 34 may output a determination result that the toe of the bucket 6 contacts the excavation target ground to the controller 30 immediately before the toe of the bucket 6 contacts the excavation target ground. Further, the excavation attachment may be controlled based on the sediment density information input in advance. Further, although the example in which the external arithmetic unit 30E is provided separately from the controller 30 has been described above, the controller 30 and the external arithmetic unit 30E may be integrally configured.

Next, a control example when the above-described invention of the present application is applied will be described. FIG. 9 is a diagram showing a configuration example of the drive system mounted on the excavator of FIG. 1, in which the mechanical power transmission line, the high-pressure hydraulic line, the pilot line, and the electric control line are double-lined, solid-lined, broken-lined, respectively. And indicated by a dotted line.

In this configuration example, the drive system of the excavator mainly includes an engine 11, a main pump 14L, 14R, a pilot pump 15, a control valve 17, an operation device 26, an operation content detection device 29, a controller 30, and an external arithmetic unit 30E. Including.

The control valve 17 includes flow rate control valves 171 to 176 that control the flow of hydraulic oil discharged by the main pumps 14L and 14R. Then, the control valve 17 passes through the flow control valves 171 to 176, the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, the traveling hydraulic motor 1A (for the left), the traveling hydraulic motor 1B (for the right), and the turning hydraulic pressure. The hydraulic oil discharged by the main pumps 14L and 14R is selectively supplied to one or more of the motors 2A. The operating device 26 is a device used by the operator to operate the hydraulic actuator. In this embodiment, the operating device 26 supplies the hydraulic oil discharged by the pilot pump 15 to the pilot ports of the flow control valves corresponding to the respective hydraulic actuators through the pilot line 25. The operation content detection device 29 is a device that detects the operation content of the operator using the operation device 26. In this embodiment, the operation content detection device 29 detects the operation direction and operation amount of the lever or pedal of the operation device 26 corresponding to each of the hydraulic actuators in the form of pressure, and outputs the detected value to the controller 30. To do. The operation content of the operating device 26 may be derived using the output of a sensor other than the pressure sensor, such as a potentiometer.

The main pumps 14L and 14R driven by the engine 11 circulate the hydraulic oil to the hydraulic oil tank via the center bypass pipelines 40L and 40R, respectively.

The center bypass pipe 40L is a high-pressure hydraulic line passing through the flow control valves 171, 173, and 175 arranged in the control valve 17, and the center bypass pipe 40R is a flow control valve arranged in the control valve 17. A high pressure hydraulic line passing through 172, 174, and 176.

The flow rate control valves 171, 172, and 173 are spool valves that control the flow rate and flow direction of the hydraulic oil flowing in and out of the traveling hydraulic motor 1A (for the left), the traveling hydraulic motor 1B (for the right), and the turning hydraulic motor 2A. Is.

Further, the flow rate control valves 174, 175, and 176 are spool valves that control the flow rate and flow direction of the hydraulic oil flowing in and out of the bucket cylinder 9, the arm cylinder 8, and the boom cylinder 7. In this embodiment, a reclaimed oil passage is formed inside the flow control valve 175. Further, a regeneration release valve 50 is attached between the flow control valve 175 and the hydraulic oil tank.

FIG. 10 is a diagram showing a configuration example of a reclaimed oil passage and a reclaimed release valve. Specifically, FIG. 10A is an enlarged view of a portion of the control valve 17 shown in FIG. 9 including the flow rate control valve 175 and the regeneration release valve 50. Further, FIG. 10B shows the flow of hydraulic oil when the opening area of the regeneration release valve 50 is minimized during the arm closing operation, and FIG. 10C shows the opening area of the regeneration release valve 50 during the arm closing operation. The flow of hydraulic oil at the maximum is shown.

The regenerated oil passage 175a is an oil passage that allows hydraulic oil that flows out from the rod side oil chamber of the arm cylinder 8 that is the contraction side oil chamber to flow (regenerate) into the bottom side oil chamber that is the extension side oil chamber when the arm is closed. .. Further, the recycled oil passage 175a includes a check valve for preventing the flow of hydraulic oil from the bottom side oil chamber to the rod side oil chamber. The regenerated oil passage 175a may be formed outside the flow rate control valve 175.

The regeneration release valve 50 is a valve that adjusts the flow rate of the hydraulic oil that flows out of the rod-side oil chamber of the arm cylinder 8 and flows into the hydraulic oil tank. In this embodiment, the regeneration release valve 50 is a solenoid valve that operates in response to a control command from the controller 30, and increases or decreases the flow path area of the oil passage 50a between the flow rate control valve 175 and the hydraulic oil tank. The flow rate of hydraulic oil flowing through each of the oil passage 50a and the reclaimed oil passage 175a is adjusted.

Specifically, as shown in FIG. 10B, the regeneration release valve 50 reduces its opening area in response to a control command from the controller 30 to reduce the flow rate of hydraulic oil flowing through the oil passage 50a. Increase the flow rate of hydraulic oil flowing through the reclaimed oil passage 175a. With this configuration, the regeneration release valve 50 can prevent the arm 5 from falling due to its own weight when the excavation attachment is operated in the air.

Further, as shown in FIG. 10C, the regeneration release valve 50 increases its opening area in response to a control command from the controller 30 to increase the flow rate of hydraulic oil flowing through the oil passage 50a and the regeneration oil passage. The flow rate of the hydraulic oil flowing through the 175a is reduced or eliminated. With this configuration, the regeneration release valve 50 reduces the excavation force by generating unnecessary pressure loss in the oil passage 50a even though the excavation release valve 50 is excavating, that is, even though the excavation attachment is in contact with the ground. It is possible to prevent it from being caused.

The regeneration release valve 50 may be installed between the rod-side oil chamber of the arm cylinder 8 and the flow rate control valve 175.

Next, with reference to FIG. 11, a process in which the controller 30 adjusts the opening area of the regeneration release valve 50 (hereinafter, referred to as “opening area adjusting process”) will be described. Note that FIG. 11 is a flowchart showing the flow of the opening area adjustment process. The controller 30 repeatedly executes this opening area adjustment process at a predetermined control cycle during the excavator operation.

First, the controller 30 determines whether the arm closing operation has been performed (step S11). In this embodiment, the controller 30 determines whether the arm operation lever is operated in the closing direction based on the output of the operation content detection device 29.

When it is determined that the arm closing operation has not been performed, the controller 30 ends the opening area adjustment process this time.

When it is determined that the arm closing operation has been performed, the controller 30 determines whether the excavation attachment and the ground are in contact with each other based on the calculation result of the external arithmetic unit 30E (step S12). In this embodiment, the external arithmetic unit 30E is based on the current position of the toe of the bucket 6 derived from the output of the attitude detection device M3 and the information on the current shape of the excavation target ground acquired by the ground shape information acquisition unit 33. It is determined whether or not the toe of the bucket 6 is in contact with the ground. The information regarding the current shape of the ground to be excavated is information reflecting the information regarding the ground shape after the excavation operation and the information regarding the ground shape after the excavation operation.

Then, when the external arithmetic unit 30E determines that the excavation attachment and the ground are in contact with each other, the controller 30 increases the opening area of the regeneration release valve 50 as necessary (step S13). In this embodiment, when the external arithmetic unit 30E determines that the toe of the bucket 6 is in contact with the ground, the external arithmetic unit 30E outputs the determination result to the controller 30. When the opening area of the regeneration release valve 50 is less than a predetermined value, the controller 30 that receives the determination result increases the opening area to a predetermined value.

On the other hand, when the external arithmetic unit 30E determines that the excavation attachment and the ground are not in contact with each other, the controller 30 reduces the opening area of the regeneration release valve 50 as necessary (step S14). In this embodiment, when the external arithmetic unit 30E determines that the toes of the bucket 6 are not in contact with the ground, the external arithmetic unit 30E outputs the determination result to the controller 30. Upon receiving the determination result, the controller 30 reduces the opening area of the regeneration release valve 50 to a predetermined value if the opening area of the regeneration release valve 50 is larger than a predetermined value.

Next, with reference to FIG. 12, the temporal transition of various parameters when the controller 30 adjusts the opening area of the regeneration release valve 50 will be described. Note that FIG. 12A shows the temporal transition of the pressure in the rod-side oil chamber of the arm cylinder 8. Further, FIG. 12B shows the time transition of the ground contact flag, and FIG. 12C shows the time transition of the opening area of the regeneration release valve 50. The time axis (horizontal axis) of FIGS. 12 (A) to 12 (C) is common. Further, the ground contact flag represents a determination result of presence / absence of contact between the excavation attachment and the ground by the external arithmetic unit 30E. Specifically, the value "OFF" of the ground contact flag represents a state in which "no contact" is determined by the external arithmetic unit 30E, and the value "ON" of the ground contact flag is "contact" by the external arithmetic unit 30E. Indicates a state in which "Yes" is determined. Further, the transition shown by the solid line in FIG. 12 represents the transition when the actual contact and the determination of “with contact” are performed at the same time. On the other hand, the transition shown by the broken line in FIG. 12 represents the transition when the determination of “with contact” is made before the actual contact, and the transition shown by the alternate long and short dash line in FIG. 12 is “with contact”. It represents the transition when the judgment is made after the actual contact.

Specifically, when the determination of "contact" is made before the actual contact, the ground contact flag is set from the value "OFF" at time t1 as shown by the broken line in FIG. 12 (B). It can be switched to "ON". In this embodiment, the actual contact occurs at time t2. Then, when the ground contact flag is switched to the value "ON", the controller 30 increases the opening area of the regeneration release valve 50. Therefore, the opening area of the regeneration release valve 50 is adjusted from the value An to the value Aw (> An) at time t1 as shown by the broken line in FIG. 12 (C). The value An is an opening area preset as an optimum value when the arm 5 is operated in the air, and the value Aw is an opening area preset as an optimum value when the arm 5 is operated during excavation. Is. As a result, the pressure in the rod-side oil chamber of the arm cylinder 8 begins to decrease at time t1 and continues to decrease until actual contact occurs, as shown by the dashed line in FIG. 12 (A). This is because the arm 5 falls under its own weight. Then, after the actual contact occurs at time t2, it starts to increase (between time t2 and time t3), and then increases to a value corresponding to the excavation reaction force as the working reaction force.

In this way, if the determination of "contact" is made before the actual contact, the controller 30 temporarily suddenly reduces the pressure in the oil chamber on the rod side of the arm cylinder 8, and thus causes cavitation. There is a risk.

On the other hand, when the determination of "contact" is made after the actual contact, the opening area of the regeneration release valve 50 remains small at the time t2 when the actual contact occurs, so that the pressure in the oil chamber on the rod side is increased. It will rise. Then, the ground contact flag is switched from the value "OFF" to the value "ON" at time t3 as shown by the alternate long and short dash line in FIG. 12B. Therefore, the opening area of the regeneration release valve 50 is adjusted from the value An to the value Aw at time t3 as shown by the alternate long and short dash line in FIG. 12C. As a result, the pressure in the rod-side oil chamber of the arm cylinder 8 begins to increase at time t2 when the actual contact occurs, as shown by the alternate long and short dash line in FIG. 12 (A), and the opening area of the regeneration release valve 50 at time t3. Continues to increase until is increased to the value Aw. This is because it is affected by the excavation reaction force and the pressure loss at the regeneration release valve 50. Then, when the opening area of the regeneration release valve 50 is increased to the value Aw at time t3, it starts to decrease, and after that, it decreases to the value corresponding to the excavation reaction force.

In this way, if the determination of "contact" is made after the actual contact, the controller 30 temporarily increases the pressure in the oil chamber on the rod side of the arm cylinder 8, so that the excavation attachment moves. It makes it unstable and reduces work efficiency.

Therefore, the external arithmetic unit 30E sets the excavation target based on the current posture of the excavation attachment detected by the attitude detection device M3 and the information on the current shape of the excavation target ground acquired by the ground shape information acquisition unit 33. Determine if it is in contact with the ground. This is because the determination of "with contact" is performed at the same time as the actual contact.

When the determination of "contact" is made at the same time as the actual contact, the ground contact flag is switched from the value "OFF" to the value "ON" at time t2 as shown by the solid line in FIG. 12 (B). Therefore, the opening area of the regeneration release valve 50 is adjusted from the value An to the value Aw at time t2, as shown by the solid line in FIG. 12 (C). As a result, the pressure in the rod-side oil chamber of the arm cylinder 8 begins to decrease at the time t2 when the actual contact occurs, and then decreases to a value corresponding to the excavation reaction force, as shown by the solid line in FIG. 12 (A). To do. It does not decrease temporarily before the actual contact occurs, and does not increase due to the pressure loss at the regeneration release valve 50 after the actual contact occurs.

With the above configuration, the controller 30 acquires information on the current shape of the ground to be worked on based on the information on the ground shape after the excavation operation and the information on the ground shape after the soil removal operation. Then, the attachment is controlled based on the acquired information on the current shape of the ground to be worked. In this embodiment, the controller 30 adjusts the opening area of the regeneration release valve 50 based on the current posture of the excavation attachment and the current shape of the excavation target ground. Specifically, the opening area of the regeneration release valve 50 is adjusted based on the current position of the toe of the bucket 6 and the current shape of the ground to be excavated. Therefore, at the same time that the toe of the bucket 6 comes into contact with the ground to be excavated, the pressure loss at the regeneration release valve 50 of the hydraulic oil flowing out from the rod side oil chamber of the arm cylinder 8 to the hydraulic oil tank can be reduced or eliminated. As a result, the controller 30 can more accurately determine the presence or absence of contact between the toe of the bucket 6 and the ground to be excavated based on a change in arm cylinder pressure or the like, and suppresses erroneous determination. it can. In addition, operability and work efficiency can be improved by suppressing erroneous determination of the presence or absence of contact. Specifically, at the same time that the toe of the bucket 6 comes into contact with the ground, the pressure loss generated at the regeneration release valve 50 to prevent the arm 5 from falling due to its own weight can be reduced or eliminated, and the pressure can be reduced. It is possible to prevent the force required for excavation from increasing by the amount of the loss. Further, it is possible to prevent the arm 5 from falling by its own weight before contact with the ground, and it is possible to prevent the occurrence of cavitation.

Further, the controller 30 can accurately estimate the current shape of the ground to be worked on even when not only excavation but also embankment, backfilling, etc. are performed. Therefore, the timing at which the toe of the bucket 6 comes into contact with the ground to be excavated can be accurately predicted, and the control timing of the control valve E1 such as the regeneration release valve 50 can be determined more appropriately.

The controller 30 may adjust the opening area of the regeneration release valve (not shown) related to the boom cylinder 7 in the same manner as adjusting the opening area of the regeneration release valve 50 related to the arm cylinder 8. The opening area of the regeneration release valve (not shown) with respect to 9 may be adjusted.

Next, another embodiment of excavation attachment control by the ground contact determination unit 34 of the external arithmetic unit 30E will be described with reference to FIGS. 13 to 15. Note that FIG. 13 is a diagram showing the relationship between the depth of the excavation target ground and the reference plane. The reference plane is a plane that serves as a reference for determining the depth of the ground to be excavated. In this embodiment, the reference plane is a horizontal plane on which the center point R of the shovel is located, and the center point R is the intersection of the turning axis of the shovel and the ground contact surface of the lower traveling body 1.

Specifically, the excavation attachment shown by the alternate long and short dash line in FIG. 13 represents the posture of the excavation attachment when excavating the excavation target ground at the same depth as the reference plane indicated by the alternate long and short dash line. In this case, the depth D of the ground to be excavated is the same as the depth D0 (= 0) of the reference plane. The depth D of the excavation target ground is derived based on the information regarding the current shape of the excavation target ground acquired by the ground shape information acquisition unit 33. Further, the depth D of the excavation target ground may be derived based on the current attitude of the excavation attachment detected by the attitude detection device M3.

Further, the excavation attachment shown by the broken line in FIG. 13 represents the posture of the excavation attachment when excavating the excavation target ground shown by the broken line. In this case, the depth D of the ground to be excavated is represented by the depth D1 (> D0).

Further, the excavation attachment shown by the solid line in FIG. 13 represents the posture of the excavation attachment when excavating the excavation target ground shown by the solid line. In this case, the depth D of the ground to be excavated is represented by the depth D2 (> D1).

The ground to be excavated may be located higher than the reference plane. In this case, the depth D of the excavation target ground may be represented by a negative value.

FIG. 14 is a diagram showing the relationship between the bucket angle θ3 and the excavation reaction force F. Specifically, FIG. 14A shows the transition of the posture of the bucket 6 when the bucket 6 is closed from the bucket angle of 30 ° to the bucket angle of 180 °. The bucket 6 shown by the broken line in FIG. 14A represents the posture when the bucket angle is 30 °, and the bucket 6 shown by the solid line in FIG. 14A represents the posture when the bucket angle is 180 °.

FIG. 14B shows an example of the contents of the correspondence table that stores in advance the correspondence between the depth D of the excavation target ground and the transition or peak value of the excavation reaction force F when a predetermined bucket closing operation is performed. .. Specifically, FIG. 14B shows the transition of the excavation reaction force F with respect to the bucket angle θ3 when the bucket 6 is closed from the bucket angle of 30 ° to the bucket angle of 180 °. The corresponding table is a data table generated based on the analysis of the measured data, and is registered in advance in, for example, the non-volatile memory.

Further, FIG. 14 (C) shows the temporal transition of the bucket angle θ3, and FIG. 14 (D) shows the temporal transition of the excavation reaction force F calculated using the corresponding table of FIG. 14 (B). The time axis (horizontal axis) of FIGS. 14 (C) and 14 (D) is common.

Further, the transition shown by the alternate long and short dash line in FIGS. 14 (B) and 14 (D) represents the transition when the depth D of the excavation target ground is the depth D0. The transition shown by the broken line represents the transition when the depth D of the excavation target ground is the depth D1, and the transition shown by the solid line represents the transition when the depth D of the excavation target ground is the depth D2.

When the bucket closing operation from the bucket angle of 30 ° to 180 ° as shown in FIGS. 14 (A) and 14 (C) is performed, the excavation reaction force F is determined in FIGS. 14 (B) and 14 (D). As shown in, the bucket angle θ3 increases to a certain angle (for example, 100 °) and then starts to decrease, and reaches zero when the bucket angle θ3 reaches 180 °. This tendency is the same regardless of the depth D of the ground to be excavated. However, the peak value of the excavation reaction force F changes according to the change in the depth D of the excavation target ground. 14 (B) and 14 (D) show, as an example, a tendency that the peak value of the excavation reaction force F increases as the depth D of the excavation target ground increases.

Therefore, the ground contact determination unit 34 of the external arithmetic unit 30E derives the current depth D of the excavation target ground based on the information regarding the current shape of the excavation target ground acquired by the ground shape information acquisition unit 33. Then, the ground contact determination unit 34 estimates the peak value of the excavation reaction force F when a predetermined bucket closing operation is performed according to the current depth D of the excavation target ground. After that, the ground contact determination unit 34 determines whether the estimated peak value of the excavation reaction force F exceeds a predetermined value. Then, when it is determined that the value exceeds the value, the movement of the excavation attachment is controlled so that the peak value does not exceed the predetermined value. This is to prevent the excavation reaction force F from becoming too large and the movement of the excavation attachment becomes unstable. For example, the ground contact determination unit 34 automatically raises the boom 4 during the bucket closing operation regardless of whether or not the operator raises the boom so that the peak value of the excavation reaction force F does not exceed a predetermined value. To. For example, the ground contact determination unit 34 automatically raises the boom 4 at a rate of increase (rotation angle of the boom 4 per unit time) that the operator does not notice. Therefore, the ground contact determination unit 34 can smooth the movement of the excavation attachment without notifying the operator that the boom 4 has automatically risen, and can improve the operability. In this case, the control target of the ground contact determination unit 34 is not the regeneration release valve 50 but the flow rate control valve 176. For example, the ground contact determination unit 34 outputs a determination result that the estimated peak value of the excavation reaction force F exceeds a predetermined value to the controller 30. Upon receiving this determination result, the controller 30 outputs a control command to the solenoid valve (not shown) as the control valve E1 for increasing or decreasing the pilot pressure of the flow rate control valve 176, and automatically causes the flow rate control valve 176 to operate. Move.

FIG. 15 shows a flow of a process in which the controller 30 automatically adjusts the posture of the excavation attachment so that the peak value of the excavation reaction force F does not exceed a predetermined value (hereinafter, referred to as “posture automatic adjustment process”). It is a flowchart. The controller 30 repeatedly executes this posture automatic adjustment process at a predetermined control cycle while the excavator is operating.

First, the controller 30 determines whether the excavation operation has been performed (step S21). In this embodiment, the controller 30 determines whether at least one of the boom operation, the arm operation, and the bucket operation has been performed based on the output of the operation content detection device 29.

Then, when it is determined that the excavation operation has been performed (YES in step S21), the controller 30 determines whether the excavation attachment and the ground are in contact with each other based on the calculation result of the external arithmetic unit 30E (step S22). In this embodiment, the external arithmetic unit 30E is based on the current position of the toe of the bucket 6 derived from the output of the attitude detection device M3 and the information on the current shape of the excavation target ground acquired by the ground shape information acquisition unit 33. It is determined whether or not the toe of the bucket 6 is in contact with the ground.

Then, when it is determined that the excavation attachment and the ground are in contact with each other (YES in step S22), the external arithmetic unit 30E estimates the peak value of the excavation reaction force F (step S23). In this embodiment, the external arithmetic unit 30E derives the current depth D of the excavation target ground based on the information regarding the current shape of the excavation target ground acquired by the ground shape information acquisition unit 33. Then, the external arithmetic unit 30E estimates the peak value of the excavation reaction force F when a predetermined bucket closing operation is performed according to the current depth D of the excavation target ground. Specifically, the external arithmetic unit 30E derives the peak value of the excavation reaction force F corresponding to the current depth D of the excavation target ground with reference to the correspondence table as shown in FIG. 14 (B). Further, the external arithmetic unit 30E may calculate the peak value of the excavation reaction force F when a predetermined bucket closing operation is performed based on the current depth D of the excavation target ground in real time. Further, the external arithmetic unit 30E may consider the sediment density and the like when calculating the peak value. The sediment density may be a value input by the operator through an in-vehicle input device (not shown), or may be a value automatically calculated based on the output of various sensors such as a cylinder pressure sensor. ..

After that, the external arithmetic unit 30E determines whether the estimated peak value of the excavation reaction force F exceeds the predetermined value Fth (step S24).

Then, when the external arithmetic unit 30E determines that the peak value exceeds the predetermined value Fth (YES in step S24), the controller 30 automatically adjusts the posture of the excavation attachment during the bucket closing operation (step S25). .. In this embodiment, the controller 30 automatically raises the boom 4 during the bucket closing operation regardless of the presence or absence of the boom raising operation by the operator. Specifically, the boom 4 is automatically raised in a predetermined operation pattern according to the change in the bucket angle θ3.

When the controller 30 determines that the excavation operation has not been performed (NO in step S21), the controller 30 determines that the excavation attachment and the ground are not in contact with each other by the external arithmetic unit 30E (NO in step S22). Alternatively, when the external arithmetic unit 30E determines that the peak value is equal to or less than the predetermined value Fth (NO in step S24), the posture automatic adjustment process of this time is performed without automatically adjusting the posture of the excavation attachment. finish.

With the above configuration, the external arithmetic unit 30E acquires information on the current shape of the ground to be worked on based on the information on the ground shape after the excavation operation and the information on the ground shape after the soil removal operation. Then, the attachment is controlled based on the acquired information on the current shape of the ground to be worked. In this embodiment, the external arithmetic unit 30E can prevent the peak value of the excavation reaction force F from exceeding the predetermined value Fth during the bucket closing operation. Therefore, it is possible to prevent the excavation reaction force F from being excessively increased and the movement of the excavation attachment from becoming unstable, and to improve the operability and work efficiency of the excavator. Further, by using the predetermined value Fth set low in the external arithmetic unit 30E, the same effect can be realized in the work other than the excavation work such as the floor digging work and the leveling work.

Although the preferred examples of the present invention have been described in detail above, the present invention is not limited to the above-mentioned examples, and various modifications and substitutions are made to the above-mentioned examples without departing from the scope of the present invention. Can be added.

For example, in the above embodiment, the external arithmetic unit 30E is based on the current posture of the excavation attachment detected by the attitude detection device M3 and the information regarding the current shape of the excavation target ground acquired by the ground shape information acquisition unit 33. To determine if the excavation attachment is in contact with the excavation target ground. Then, when it is determined that they are in contact with each other, the controller 30 outputs a control command to the regeneration release valve 50 to increase the opening area thereof. Alternatively, when it is determined that they are in contact with each other, the peak value of the excavation reaction force F when the predetermined bucket closing operation is performed is estimated, and when the estimated peak value exceeds the predetermined value Fth, the boom 4 is moved. It is automatically increased so that the actual peak value is equal to or less than the predetermined value Fth. However, the present invention is not limited to these configurations. For example, the external arithmetic unit 30E may increase the driving force of the attachment (for example, the excavation force by the excavation attachment) when it is determined that they are in contact with each other. Specifically, the external arithmetic unit 30E may increase the rotation speed of the engine 11 or increase the discharge amounts of the main pumps 14L and 14R. In this case, the control target of the ground contact determination unit 34 is not the regeneration release valve 50 but the regulator of the engine 11 or the main pump 14.

Further, the external arithmetic unit 30E automatically raises the boom 4 when it is determined that the peak value of the excavation reaction force F exceeds the predetermined value Fth even in the case of remote operation or automatic excavation operation (unmanned operation). You may let me. This is to reduce the excavation reaction force F and continue the smooth excavation work.

Further, in the above-described embodiment, the terrain database update unit 31 updates the terrain database by acquiring the terrain information of the work site through the communication device M1 when the excavator is started. However, the present invention is not limited to this configuration. For example, the terrain database update unit 31 may update the terrain database by acquiring the terrain information of the work site based on the image around the excavator captured by the imaging device.

FIG. 16 is a functional block diagram showing a configuration example of the external arithmetic unit 30E connected to the image pickup apparatus M5. The configuration of FIG. 16 is different from the configuration of FIG. 4 in that the imaging device M5 is connected instead of the communication device M1, but is common in other points. Therefore, the description of the common part will be omitted, and the difference part will be described in detail.

The image pickup device M5 is a device that acquires an image of the periphery of the excavator. In this embodiment, the image pickup apparatus M5 is a camera attached to the upper swivel body 3 of the excavator, recognizes the distance to the ground around the excavator based on the captured image, and acquires the topographical information of the work site. The image pickup device M5 may be a stereo camera, a distance image camera, a three-dimensional laser scanner, or the like.

Further, the image pickup apparatus M5 may be attached to the outside of the excavator. In this case, the external arithmetic unit 30E may acquire the terrain information output by the image pickup device M5 via the communication device M1. Specifically, the image pickup apparatus M5 may be attached to a multicopter for aerial photography, a steel tower installed at a work site, or the like, and may acquire topographical information of the work site based on an image of the work site viewed from above. Further, when the image pickup device M5 is attached to the multicopter for aerial photography, the image pickup device M5 captures an image of the work site viewed from above at a frequency of about once an hour or in real time to acquire topographical information of the work site. You may. The terrain information acquired by the image pickup apparatus M5 is used for updating the terrain database. The update interval is longer than the update interval of the terrain database based on the signal from the attitude detection device M3 when the income interval of the terrain information is 1 hour or more.

17 to 19 are functional block diagrams showing another configuration example of the external arithmetic unit 30E connected to the image pickup apparatus M5. The configuration of FIG. 17 differs from the configuration of FIG. 4 in that each of the terrain database update unit 31 and the position coordinate update unit 32 uses the output of the image pickup device M5 (particularly, the image pickup device M5 outside the excavator). It is common in other points. In the embodiment of FIG. 17, the terrain database update unit 31 acquires the terrain information of the work site through the communication device M1 once a day, and images the terrain once an hour or in real time. The terrain information of the work site is acquired through the device M5 and the terrain database is updated. Further, the position coordinate updating unit 32 updates the data related to the coordinates and the direction representing the current position of the excavator in real time by using the output of the positioning device M2 and the output of the imaging device M5 together. The position coordinate update unit 32 may update the data relating to the coordinates and the orientation representing the current position of the excavator in real time based only on the output of the image pickup apparatus M5.

The configuration of FIG. 18 is different from the configuration of FIG. 4 in that the position coordinate updating unit 32 uses only the output of the imaging device M5 and the positioning device M2 is omitted, but is common in other respects. Further, the configuration of FIG. 19 is similar to that of FIG. 4 in that each of the terrain database update unit 31 and the position coordinate update unit 32 uses only the output of the image pickup device M5, and the communication device M1 and the positioning device M2 are omitted. They are different, but they are common in other respects.

In this way, the external arithmetic unit 30E may acquire the terrain information of the work site based on the output of the image pickup apparatus M5 and update the terrain database, and obtains data on the coordinates and orientation representing the current position of the excavator in real time. You may update it.

Further, in the above-described embodiment, the external arithmetic unit 30E has been described as another arithmetic unit outside the controller 30, but it may be integrally integrated with the controller 30.

1 ... Lower traveling body 1A ... Running hydraulic motor (for left) 1B ... Running hydraulic motor (for right) 2 ... Swivel mechanism 2A ... Swivel hydraulic motor 3 ... Upper swivel Body 4 ... Boom 5 ... Arm 6 ... Bucket 7 ... Boom cylinder 8 ... Arm cylinder 9 ... Bucket cylinder 10 ... Cabin 11 ... Engine 11a ... Alternator 11b・ ・ ・ Starter 11c ・ ・ ・ Water temperature sensor 14L, 14R ・ ・ ・ Main pump 14a ・ ・ ・ Regulator 14b ・ ・ ・ Discharge pressure sensor 14c ・ ・ ・ Oil temperature sensor 15 ・ ・ ・ Pilot pump 15a, 15b ・ ・ ・ Flood control Sensor 16 ... High-pressure hydraulic line 17 ... Control valve 25, 25a ... Pilot line 26 ... Operating device 26A to 26C ... Lever or pedal 29 ... Operation content detection device 30 ... Controller 30a ・ ・ ・ Temporary storage unit 30E ・ ・ ・ External calculation device 31 ・ ・ ・ Topography database update unit 32 ・ ・ ・ Position coordinate update unit 33 ・ ・ ・ Ground shape information acquisition unit 34 ・ ・ ・ Ground contact judgment unit 40 ・ ・・ Image display device 40a ・ ・ ・ Conversion processing unit 40L, 40R ・ ・ ・ Center bypass pipeline 41 ・ ・ ・ Image display unit 42 ・ ・ ・ Input unit 42a ・ ・ ・ Light switch 42b ・ ・ ・ Wiper switch 42c ・ ・ ・Window washer switch 50 ・ ・ ・ Regeneration release valve 50a ・ ・ ・ Oil passage 70 ・ ・ ・ Storage battery 72 ・ ・ ・ Electrical components 74 ・ ・ ・ Engine control device (ECU) 75 ・ ・ ・ Engine rotation speed adjustment dial 171 to 176 ・・ ・ Flow control valve 175a ・ ・ ・ Recycled oil passage E1 ・ ・ ・ Control valve M1 ・ ・ ・ Communication device M2 ・ ・ ・ Positioning device M3 ・ ・ ・ Attitude detection device M3a ・ ・ ・ Boom angle sensor M3b ・ ・ ・ Arm angle Sensor M3c ・ ・ ・ Bucket angle sensor M3d ・ ・ ・ Body tilt sensor M4 ・ ・ ・ Cylinder pressure detection device M5 ・ ・ ・ Imaging device

However, the excavator described above determines whether to reduce or increase the flow rate of hydraulic oil flowing through the variable throttle only after detecting the contact between the bucket and the ground based on the pressure in the oil chamber on the bottom side of the arm cylinder. Can not. As a result, the flow rate cannot be increased at the start of excavation, causing unnecessary pressure loss at the variable throttle and reducing the working efficiency of the excavator. This is because the current shape of the ground to be excavated is not known, so it is not possible to determine in advance when the bucket will come into contact with the ground. As described above, Patent Document 1 describes only when the bucket and the ground come into contact with each other, and there is no description after the soil is discharged.

In view of the above, it is desired to provide an excavator capable of recognizing the shape of earth and sand after soil removal.

Excavator according to an embodiment of the present invention includes a lower traveling structure, an upper revolving structure to be mounted on the lower traveling body, attached to the upper rotating body, and attachments that are controlled by the control valve, the position of the attachment An excavator including a posture detection device for detecting and a control device, the control device obtains shape information of earth and sand before the soil discharge operation is performed by the bucket constituting the attachment, and the soil discharge operation by the bucket. Update after .

By the above-mentioned means, a shovel capable of recognizing the shape of earth and sand after excretion is provided.

Claims (8)

With the lower running body,
The upper swivel body mounted on the lower traveling body and
The attachment attached to the upper swing body and
A posture detection device that detects the posture of the attachment, and
A shovel equipped with a control device,
The control device acquires information on the current shape of the ground to be worked on based on the transition of the posture of the attachment detected by the posture detection device.
The acquired information on the current shape of the ground to be worked on includes information on the shape of the ground that changes due to soil removal.
Excavator. The control device acquires information on the current shape of the ground to be worked on based on the transition of the posture of the attachment detected by the posture detection device and the sediment characteristic table stored in advance.
The excavator according to claim 1. The control device controls the attachment based on the acquired information about the current shape of the ground to be worked on.
The excavator according to claim 1 or 2. The control device acquires the depth of the work target ground with respect to the reference plane based on the acquired information on the current shape of the work target ground, and controls the working posture of the attachment according to the depth. To do
The excavator according to any one of claims 1 to 3. The control device controls the posture of the attachment according to the working reaction force corresponding to the depth.
The excavator according to claim 4. The control device determines whether or not the attachment is in contact with the ground of the work target based on the posture of the attachment detected by the posture detection device and the acquired information on the current shape of the ground of the work target. ,
The excavator according to any one of claims 1 to 5. A hydraulic cylinder that operates the work elements that make up the attachment,
A reclaimed oil passage that allows hydraulic oil that flows out of the contraction side oil chamber of the hydraulic cylinder to flow into the extension side oil chamber of the hydraulic cylinder during the operation of the work element.
It has a regeneration release valve, which is arranged between the hydraulic cylinder and the hydraulic oil tank.
When the control device determines that the attachment is in contact with the ground to be worked on, the control device increases the opening area of the regeneration release valve.
The excavator according to claim 6. When the control device determines that the attachment is in contact with the ground to be worked on, the control device increases the driving force of the attachment.
The excavator according to claim 6 or 7.

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