CN111492111B

CN111492111B - Excavator

Info

Publication number: CN111492111B
Application number: CN201780097756.4A
Authority: CN
Inventors: 吴春男
Original assignee: Sumitomo Heavy Industries Ltd
Current assignee: Sumitomo Heavy Industries Ltd
Priority date: 2017-12-18
Filing date: 2017-12-18
Publication date: 2022-10-25
Anticipated expiration: 2037-12-18
Also published as: WO2019123511A1; CN111492111A; JPWO2019123511A1

Abstract

An excavator according to an embodiment of the present invention includes: a lower traveling body (1); an upper revolving body (3) mounted on the lower traveling body (1); an attachment device mounted on the upper slewing body (3); an operation device (26) provided in a cab (10) attached to an upper slewing body (3); and a controller (30) for controlling the operation of the attachment device operated in accordance with the composite operation of the operation device (26). The controller (30) derives an operation tendency of an operator within a predetermined period, and controls the operation of the attachment so as to maintain the operation of the attachment in accordance with the operation tendency.

Description

Excavator

Technical Field

The present disclosure relates to a shovel including a plurality of hydraulic actuators capable of performing a combined operation.

Background

A shovel that controls the operation of a front end work machine by performing a compound operation on a plurality of hydraulic cylinders is known (see patent document 1). The shovel is provided with an area limit switch for selecting an area limit excavation control mode and a setting switch for commanding setting of an excavation area (target excavation surface) in the area limit excavation control mode. An operator of the excavator sets the boundary of the target excavation face by the setting switch and starts the area limitation excavation control mode by the area limitation switch. In the area-restricted excavation control mode, the excavator controls the operation of the front end working machine so that the front end of the bucket moves along the boundary of the excavation area.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 11-350537

Disclosure of Invention

Technical problem to be solved by the invention

However, the excavator of patent document 1 is inconvenient to use because it forces the operator of the excavator to perform complicated operations such as setting of an excavation area and switching of modes in order to start the area limitation excavation control mode.

Accordingly, it is desirable to provide an excavator that facilitates the function of assisting the compound operation.

Means for solving the technical problems

An excavator according to an embodiment of the present invention includes: a lower traveling body; an upper slewing body mounted on the lower traveling body; an attachment mounted to the upper slewing body; an operating device provided in a control room mounted on the upper slewing body; and a control device that controls an operation of the attachment that operates in accordance with a composite operation on the operation device, the control device deriving an operation tendency of an operator for a predetermined period and controlling the operation of the attachment so as to maintain the operation of the attachment in accordance with the operation tendency.

ADVANTAGEOUS EFFECTS OF INVENTION

By the means, the excavator with the auxiliary combined operation function more convenient can be provided.

Drawings

Fig. 1 is a side view of an excavator according to an embodiment of the present invention.

Fig. 2 is a diagram showing a configuration example of a drive system of the shovel of fig. 1.

Fig. 3 is a diagram showing a configuration example of an operating device to which an adjustment mechanism is attached.

Fig. 4A is a side view of the shovel used in the explanation of the three-dimensional orthogonal coordinate system.

Fig. 4B is a plan view of the shovel used for explanation of the three-dimensional orthogonal coordinate system.

Fig. 5 is a diagram illustrating a state of the accessory device in the XZ plane.

Fig. 6 is a flowchart of the attachment operation control process.

Fig. 7 is a graph showing changes over time in the boom raising operation amount, the arm closing operation amount, the cutting edge speed, and the cutting edge angle.

Fig. 8 is a block diagram showing the flow of automatic control.

Fig. 9 is a block diagram showing the flow of automatic control.

Fig. 10 is a diagram showing a configuration example of an operation system including an electric operation device.

Fig. 11 is a diagram showing another configuration example of an operation system including an electric operation device.

Detailed Description

Fig. 1 is a side view showing a shovel (excavator) as a construction machine to which the present invention is applied. An upper revolving body 3 is mounted on a lower traveling body 1 of the excavator via a revolving mechanism 2. A boom 4 is attached to the upper slewing body 3. An arm 5 is attached to a distal end of the boom 4, and a bucket 6 as a terminal attachment is attached to a distal end of the arm 5. The boom 4, the arm 5, and the bucket 6 as the working elements constitute an excavation attachment as an example of an attachment. The boom 4, the arm 5, and the bucket 6 are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, respectively. An operator's cab 10 as a cab is provided in the upper revolving structure 3, and a power source such as an engine 11 is mounted thereon.

Fig. 2 is a block diagram showing a configuration example of a drive system of the shovel of fig. 1, and a mechanical power transmission line, a hydraulic oil line, a pilot line, and an electric control line are indicated by a double line, a thick solid line, a broken line, and a dotted line, respectively.

The excavator drive system mainly includes an engine 11, a regulator 13, a main pump 14, a pilot pump 15, a control valve 17, an operation device 26, a pressure sensor 29, a controller 30, a posture detection device S1, and the like.

The engine 11 is a drive source of the shovel. In the present embodiment, the engine 11 is, for example, a diesel engine as an internal combustion engine that operates to maintain a predetermined rotation speed. An output shaft of the engine 11 is coupled to input shafts of the main pump 14 and the pilot pump 15.

The main pump 14 is a device for supplying hydraulic oil to the control valve 17 via a hydraulic oil line, and is, for example, a swash plate type variable displacement hydraulic pump.

Regulator 13 is a device for controlling the discharge amount of main pump 14. In the present embodiment, regulator 13 controls the discharge amount of main pump 14 by adjusting the swash plate tilt angle of main pump 14 in accordance with, for example, the discharge pressure of main pump 14, a command current from controller 30, and the like.

The pilot pump 15 is a device that supplies hydraulic oil to various hydraulic control devices including the operation device 26 via a pilot line, and is, for example, a fixed displacement hydraulic pump.

The control valve 17 is a hydraulic control device that controls a hydraulic system in the shovel. Specifically, control valve 17 includes a plurality of control valves that control the flow of hydraulic oil discharged from main pump 14. Also, the control valve 17 selectively supplies the working oil discharged from the main pump 14 to 1 or more hydraulic actuators through these control valves. These control valves control the flow rate of the hydraulic oil flowing from the main pump 14 to the hydraulic oil tank through the intermediate bypass line, the flow rate of the hydraulic oil flowing from the main pump 14 to the hydraulic actuator, and the flow rate of the hydraulic oil flowing from the hydraulic actuator to the hydraulic oil tank. The hydraulic actuator includes a boom cylinder 7, a stick cylinder 8, a bucket cylinder 9, a left-side travel hydraulic motor 1L, a right-side travel hydraulic motor 1R, and a turning hydraulic motor 2A.

The operating device 26 is a device used by an operator to operate the hydraulic actuator. In the present embodiment, the operation device 26 is provided in the cab 10, and supplies the hydraulic oil discharged from the pilot pump 15 to the pilot ports of the control valves corresponding to the respective hydraulic actuators via the pilot lines. The pressure of the hydraulic oil supplied to each pilot port (hereinafter referred to as "pilot pressure") is a pressure corresponding to the operation direction and the operation amount of the joystick or the pedal of the operation device 26 corresponding to each hydraulic actuator.

The pressure sensor 29 is a sensor for detecting the content of an operation on the operation device 26. In the present embodiment, the pressure sensor 29 detects, for example, the operation direction and the operation amount of the joystick or the pedal of the operation device 26 corresponding to each hydraulic actuator in the form of pressure, and outputs the detected values to the controller 30. The operation content of the operation device 26 may be detected by a sensor other than the pressure sensor.

The attitude detecting device S1 detects an attitude of the excavation attachment. In the present embodiment, the attitude detection device S1 includes a vehicle body inclination sensor, a boom angle sensor, an arm angle sensor, and a bucket angle sensor. The boom angle sensor is a sensor for acquiring a boom angle, and includes, for example, a rotation angle sensor for detecting a rotation angle of the boom 4 around a boom foot pin, a stroke sensor for detecting a stroke amount of the boom cylinder 7, and an inclination (acceleration) sensor for detecting an inclination angle of the boom 4. The same applies to the arm angle sensor and the bucket angle sensor. Each of the body tilt sensor, the boom angle sensor, the arm angle sensor, and the bucket angle sensor may be a combination of an acceleration sensor and a gyro sensor. In this case, desired angles such as a vehicle body inclination angle, a boom angle, an arm angle, and a bucket angle can be calculated from outputs of the acceleration sensor and the gyro sensor.

The controller 30 is a control device for controlling the shovel. In the present embodiment, the controller 30 is constituted by a computer having a CPU, RAM, NVRAM, ROM, and the like, for example. The controller 30 reads programs corresponding to the accessory control unit 31 and the operation tendency determination unit 32 from the ROM, loads the programs into the RAM, and causes the CPU to execute corresponding processing.

The accessory device control unit 31 is a functional element for controlling the operation of the accessory device. The operation tendency determination unit 32 is a functional element for determining the operation tendency of the operator. Basically, the attachment operates in accordance with the operation of each of the plurality of operation devices 26. In addition, for example, when the operation contents of each of the plurality of operation devices 26 during a predetermined period satisfy a predetermined start condition, the operation tendency determination unit 32 derives the operation tendency of the operator during the predetermined period. The attachment control unit 31 controls the operation of the attachment so as to maintain the operation of the attachment in accordance with the operation tendency until a predetermined release condition is satisfied.

The start condition includes, for example, "the operation amounts of the respective plurality of operation devices 26 are maintained for a predetermined period". Specifically, the operation amount of each of the plurality of operation devices 26 is smaller than the predetermined operation amount for a predetermined period, and the operation amount of each of the plurality of operation devices 26 is smaller than the predetermined operation amount for a predetermined period and the fluctuation width thereof is smaller than the predetermined value.

The operation tendency is derived and defined by the operation tendency determination unit 32, for example, based on the moving direction of the terminating attachment within a predetermined period. The direction of movement is for example expressed in an angle relative to the horizontal. The operational tendency is derived and specified in terms of the speed and direction of movement of the terminating attachment.

Specifically, the operation tendency includes, for example, an operation tendency to bring the cutting edge straight line of the bucket 6 closer to the body, an operation tendency to bring the cutting edge straight line of the bucket 6 farther from the body, an operation tendency to linearly raise the cutting edge of the bucket 6, an operation tendency to linearly lower the cutting edge of the bucket 6, and the like. The linear motion may include a rotation-based motion. This is to realize the leveling work in the rotation direction.

The release condition includes, for example, "any of the plurality of operation devices 26 is equal to or greater than a predetermined operation amount", "any of the plurality of operation devices 26 is equal to or greater than a predetermined speed", "any of the operation devices 26 being operated is returned to the neutral position", and "any of the operation devices 26 being operated is operated in the reverse direction beyond the neutral position", and the like.

Basically, the excavation attachment is operated by operating a boom lever, an arm lever, and a bucket lever as the operation devices 26, respectively. The operation tendency determination unit 32 grasps each operation content based on, for example, pilot pressures generated by the boom lever and the arm lever, respectively. When the operation contents of the boom lever and the arm lever during the predetermined period satisfy the predetermined start condition, the operation tendency of the operator during the predetermined period is derived from the operation contents. In this case, the operation tendency determination unit 32 may consider the operation contents of the bucket lever, the swing lever, and the like. In the present embodiment, the boom lever and the bucket lever are described as independent levers, but actually 1 lever is the same and only the tilting direction is different. The same applies to the relationship between the arm lever and the swing lever.

In the present embodiment, the start condition is, for example, that the operation amount of each of the boom lever and the arm lever is smaller than a predetermined operation amount for a predetermined period (micro operation).

The operation tendency is derived as, for example, an operation tendency (horizontal extension in the foundation excavation operation) in which the cutting edge of the bucket 6 linearly approaches along the horizontal plane. In this case, the moving direction of the cutting edge of the bucket 6 is derived as a direction having an angle of zero degrees with respect to the horizontal plane.

Then, the attachment control unit 31 automatically controls the operation of the excavation attachment so as to maintain the operation of the excavation attachment according to the operation tendency until a predetermined cancel condition is satisfied.

Specifically, the attachment control unit 31 automatically extends and retracts the boom cylinder 7 and the arm cylinder 8 so as to maintain the moving direction (target moving direction) of the cutting edge of the bucket 6 in accordance with the operation tendency derived by the operation tendency determination unit 32. The bucket cylinder 9 can be automatically extended and retracted, and the swing hydraulic motor can be automatically rotated.

For example, when the moving direction of the cutting edge (the movement direction before adjustment) calculated from the actual operation amounts of the boom lever and the arm lever by the operator deviates from the target moving direction, the attachment control unit 31 maintains the target moving direction by the adjustment operation of the excavation attachment. In this case, the attachment control unit 31 automatically extends and contracts the boom cylinder 7 and the arm cylinder 8 regardless of the actual operation amount of the operator, thereby maintaining the target movement direction.

Here, an example of an adjusting mechanism for realizing an adjusting operation of the excavation attachment will be described with reference to fig. 3. Fig. 3 is a diagram showing a configuration example of the arm lever 26A as the operation device 26 to which the adjustment mechanism 50 is attached. The following description is also applicable to other joysticks to which the adjustment mechanism 50 is attached. For example, the same applies to a boom lever to which the adjustment mechanism 50 is attached for moving the boom flow rate control valve 17B leftward and rightward.

The adjustment mechanism 50 is a mechanism that adjusts the pilot pressure generated by the arm lever 26A to a desired pilot pressure, and mainly includes a solenoid valve 51, a solenoid valve 52L, a solenoid valve 52R, and the like. The desired pilot pressure is a pilot pressure required to align the pre-adjustment movement direction of the cutting edge of the bucket 6 to the target movement direction. The attachment control unit 31 calculates a desired pilot pressure from the output of the posture detection device S1 and the like.

The solenoid valve 51 is an electromagnetic proportional pressure reducing valve provided in a pipe line connecting the pilot pump 15 and the arm lever 26A, and the opening area thereof is increased or decreased in accordance with a control current from the controller 30.

The electromagnetic valve 52L is an electromagnetic switching valve provided in a conduit C1 connecting the arm lever 26A and the left pilot port 17L of the arm flow control valve 17A provided in the control valve 17, and its valve position is switched in accordance with a command from the controller 30. The solenoid valve 52L has a1 st valve position and a 2 nd valve position. The 1 st valve position places line C11 in communication with line C12 and shuts off line C3 from line C12. The 2 nd valve position shuts off communication between line C11 and line C12 and communicates line C3 with line C12. The pipe C11 connects the arm lever 26A and the solenoid valve 52L. The conduit C12 connects the solenoid valve 52L and the left pilot port 17L of the arm flow control valve 17A. The line C3 connects the solenoid valve 51 and the solenoid valve 52L.

The solenoid valve 52R is an electromagnetic switching valve provided in a pipe line C2 connecting the arm lever 26A and the right pilot port 17R of the arm flow control valve 17A, and the valve position thereof is switched in accordance with a command from the controller 30. The solenoid valve 52R has a1 st valve position and a 2 nd valve position. The 1 st valve position places line C21 in communication with line C22 and shuts off line C4 from line C22. The 2 nd valve position shuts off communication between line C21 and line C22 and communicates line C4 with line C22. The conduit C21 connects the arm lever 26A and the solenoid valve 52R. The conduit C22 connects the solenoid valve 52R and the right pilot port 17R of the arm flow control valve 17A. The line C4 connects the solenoid valve 51 and the solenoid valve 52R.

The arm lever 26A increases the pressure of the hydraulic oil in the conduit C1 when tilted in the closing direction, and increases the pressure of the hydraulic oil in the conduit C2 when tilted in the opening direction. The arm closing pilot pressure, which is the pressure of the hydraulic oil in the pipe C1, is detected by an arm closing pilot pressure sensor 29L, which is an example of the pressure sensor 29. The arm opening pilot pressure, which is the pressure of the hydraulic oil in the pipe C2, is detected by an arm opening pilot pressure sensor 29R, which is an example of the pressure sensor 29. When the arm closing pilot pressure increases, the arm flow control valve 17A as a spool moves in the right direction, the main pump 14 communicates with the bottom side oil chamber of the arm cylinder 8, and the arm cylinder 8 extends. When the arm opening pilot pressure increases, the arm flow control valve 17A moves leftward, the main pump 14 communicates with the rod side oil chamber of the arm cylinder 8, and the arm cylinder 8 contracts.

When the arm cylinder 8 is automatically extended, the attachment control unit 31 outputs a command current to the solenoid valve 51 and outputs an open command to the solenoid valve 52L. The solenoid valve 51 that receives the command current realizes an opening area corresponding to the command current. The solenoid valve 52L that has received the open command is switched to the 2 nd valve position, and the hydraulic oil discharged from the pilot pump 15 is caused to flow into the conduit C12. In this way, the attachment control unit 31 generates a desired arm closing pilot pressure.

Similarly, when the arm cylinder 8 is automatically contracted, the attachment control unit 31 outputs a command current to the solenoid valve 51 and outputs an open command to the solenoid valve 52R. The solenoid valve 51 that receives the command current realizes an opening area corresponding to the command current. The solenoid valve 52R that has received the open command is switched to the 2 nd valve position, and the hydraulic oil discharged from the pilot pump 15 is caused to flow into the conduit C22. In this way, the attachment control unit 31 generates a desired arm opening pilot pressure.

In this way, the controller 30 sets, for example, the moving speed and the moving direction of the bucket 6 for a predetermined period as the target moving speed and the target moving direction. Then, based on the detection value of the posture detection device S1, a command is output to the solenoid valve 51, the solenoid valve 52L, and the solenoid valve 52R so that the movement speed and the movement direction of the bucket 6 become the target movement speed and the target movement direction.

Next, a three-dimensional orthogonal coordinate system used in the control method according to the embodiment of the present invention will be described with reference to fig. 4A and 4B. Fig. 4A is a side view of the shovel, and fig. 4B is a plan view of the shovel.

As shown in fig. 4A and 4B, the Z axis of the three-dimensional orthogonal coordinate system corresponds to the revolving axis PC of the shovel, and the origin O of the three-dimensional orthogonal coordinate system corresponds to the intersection of the revolving axis PC and the installation surface of the shovel.

An X axis orthogonal to the Z axis extends in the extending direction of the attachment, and a Y axis orthogonal to the Z axis extends in a direction orthogonal to the extending direction of the attachment. The X-axis and the Y-axis rotate around the Z-axis together with the rotation of the shovel. In addition, the turning angle θ of the shovel is a counterclockwise direction with respect to the Z axis as a positive direction in a plan view as shown in fig. 4B.

As shown in fig. 4A, the mounting position of the boom 4 to the upper slewing body 3 is indicated by a boom pin position P1, which is the position of a boom pin serving as a boom rotation axis. Similarly, the attachment position of the arm 5 to the boom 4 is indicated by an arm pin position P2, which is the position of an arm pin that is an arm rotation axis. The attachment position of the bucket 6 to the arm 5 is represented by a bucket pin position P3, which is the position of a bucket pin that is a bucket rotation shaft. The front end position of the bucket 6 (for example, the cutting edge position of the bucket 6) is indicated by a bucket cutting edge position P4.

The length of a line segment SG1 connecting the boom pin position P1 and the arm pin position P2 is a predetermined value L as the boom length ₁ The length of a line segment SG2 connecting the bucket pin position P2 and the bucket pin position P3 is defined as the arm length, and the predetermined value L is shown ₂ The length of a line segment SG3 connecting the bucket pin position P3 and the bucket cutting edge position P4 is defined as a bucket length by a predetermined value L ₃ To indicate.

A boom rotation angle β as a ground angle, which is an angle formed between the line segment SG1 and the horizontal plane ₁ The angle formed between the line segment SG2 and the horizontal plane, and the arm rotation angle β as the ground angle are shown ₂ The bucket rotation angle β is represented by an angle formed between the line segment SG3 and the horizontal plane as a ground angle ₃ To indicate.

Here, assuming that the three-dimensional coordinates of the boom pin position P1 are (X, Y, Z) = (H) _OX 、O、H _OZ ) Assuming that the three-dimensional coordinates of the bucket cutting edge position P4 are (X, Y, Z) = (Xe, ye, ze), xe, ze are expressed by expression (1) and expression (2), respectively. Xe and Ye denote the plane positions of the cutting edge of the bucket 6, and Ze denotes the height of the cutting edge of the bucket 6.

Xe＝H _OX +L ₁ cosβ ₁ +L ₂ cosβ ₂ +L ₃ cosβ ₃ ……(1)

Ze＝H _Oz +L ₁ sinβ ₁ +L ₂ sinβ ₂ +L ₃ sinβ ₃ ……(2)

Further, ye is 0. This is because the bucket tip position P4 exists on the XZ plane.

Since the coordinate value of the boom pin position P1 is a fixed value, the boom rotation angle β may be determined only ₁ Angle of rotation beta of bucket arm ₂ And bucket rotation angle beta ₃ The coordinate value of the bucket cutting edge position P4 is uniquely determined. Likewise, only the boom rotation angle β is determined ₁ Then, the coordinate value of the arm pin position P2 is uniquely determined as long as the boom rotation angle β is determined ₁ And angle of rotation beta of the dipper ₂ The coordinate value of the bucket pin position P3 is uniquely determined.

Next, a case where the position of the cutting edge of the bucket 6, which is the working portion, is moved along the X axis while maintaining the values of the Y coordinate and the Z coordinate will be described with reference to fig. 4A. When the cutting edge position of the bucket 6 moves from point X0 to point X1, the arm 5 rotates in the closing direction about the arm pin position P2. Accordingly, the boom 4 rotates in the raising direction about the boom pin position P1. When the cutting edge position reaches point X1 and then the boom 4 moves from point X1 to point X2, the arm 5 rotates in the closing direction around the arm pin position P2, but the boom 4 rotates in the lowering direction around the boom pin position P1. In this way, the rotation direction of the boom 4 is reversed with the point X1 as a boundary. Therefore, even when the working site is moved linearly in the same direction, the operator needs a complicated operation.

Next, referring to fig. 5, the outputs of the boom angle sensor, the arm angle sensor, and the bucket angle sensor, and the boom rotation angle β are compared ₁ Angle of rotation beta of bucket arm ₂ And bucket rotation angle beta ₃ The relationship between them will be explained. Fig. 5 is a diagram illustrating a state of the accessory device in the XZ plane.

In the example of fig. 5, the boom angle sensor is provided at a boom pin position P1, the arm angle sensor is provided at an arm pin position P2, and the bucket angle sensor is provided at a bucket pin position P3.

The boom angle sensor detects and outputs an angle α formed between a line segment SG1 and a vertical line ₁ . The arm angle sensor detects and outputs an angle α formed between an extension line of the line segment SG1 and the line segment SG2 ₂ . The bucket angle sensor detects and outputs an angle α formed between an extension line of the line segment SG2 and the line segment SG3 ₃ . In fig. 5, with respect to the angle α ₁ The counterclockwise direction with respect to the line segment SG1 is set as the positive direction. Likewise, with respect to angle α ₂ The counterclockwise direction with respect to the line segment SG2 is set as the positive direction with respect to the angle α ₃ The counterclockwise direction with respect to the line segment SG3 is set as the positive direction. In fig. 5, the boom rotation angle β is shown ₁ Angle of rotation beta of bucket arm ₂ And bucket rotation angle beta ₃ The counterclockwise direction with respect to a line parallel to the X axis is defined as the positive direction.

According to the above relation, the boom rotates by the angle β ₁ Angle of rotation beta of bucket arm ₂ And bucket rotation angle beta ₃ Using angle alpha ₁ 、α ₂ 、α ₃ And are represented by formula (3), formula (4) and formula (5), respectively.

β ₁ ＝90-α ₁ ……(3)

β ₂ ＝β ₁ -α ₂ ＝90-α ₁ -α ₂ ……(4)

β ₃ ＝β ₂ -α ₃ ＝90-α ₁ -α ₂ -α ₃ ……(5)

Also, as described above, β ₁ 、β ₂ 、β ₃ The inclination of the boom 4, arm 5, and bucket 6 with respect to the horizontal plane is shown.

Therefore, if expressions (1) to (5) are used, the angle α is determined ₁ 、α ₂ 、α ₃ Angle of rotation of the boom beta ₁ Bucket rod rotation angle beta ₂ And bucket rotation angle beta ₃ Is uniquely determined, and the coordinate value of the bucket cutting edge position P4 is uniquely determined. Likewise, as long as the angle α is determined ₁ Angle of rotation of the boom beta ₁ And the coordinate value of the arm pin position P2 is uniquely determined as long as the angle α is determined ₁ 、α ₂ Angle of rotation of dipper beta ₂ And the coordinate value of the bucket pin position P3 are uniquely determined.

Movable arm angle sensor and bucket rodThe angle sensor and the bucket angle sensor can also directly detect the rotation angle beta of the movable arm ₁ Angle of rotation beta of bucket arm ₂ And bucket rotation angle beta ₃ . In this case, the operations of equations (3) to (5) can be omitted.

Next, a process of controlling the operation of the attachment by the controller 30 (hereinafter referred to as "attachment operation control process") will be described with reference to fig. 6. Fig. 6 is a flowchart of the attachment operation control process.

First, the controller 30 detects the operation amounts of the boom lever and the arm lever, respectively (step ST 1). For example, the controller 30 continuously detects the operation amounts of the boom lever and the arm lever based on the output of the pressure sensor 29 and stores the operation amounts in the RAM.

Then, the controller 30 determines whether or not the respective operation amounts of the boom lever and the arm lever are held for a predetermined period (step ST 2). For example, the controller 30 refers to a change over time in the operation amount of each of the boom lever and the arm lever stored in the RAM, and determines whether or not each operation amount is smaller than a predetermined operation amount over a predetermined period. Alternatively, it may be determined whether or not each operation amount is smaller than a predetermined operation amount over a predetermined period and whether or not the fluctuation width of each operation amount in the predetermined period is smaller than a predetermined value. Here, the period (predetermined period) and the fluctuation range (predetermined value) necessary for the determination may be arbitrarily determined for each operation content, each model, and each operator, for example. Further, the controller 30 may determine whether or not each operation amount is held for a predetermined period based on whether or not the cutting edge of the bucket 6, which is the working portion, is operated linearly for a predetermined period. That is, the controller 30 may determine whether the cutting edge of the bucket 6, which is the working portion, is operated linearly for a predetermined period in order to derive the operation tendency of the operator for the predetermined period.

When it is determined that the respective operation amounts are held for the predetermined period (yes in step ST 2), the controller 30 determines the target moving speed of the cutting edge of the bucket 6 (step ST 3). For example, the controller 30 derives the movement locus and the movement distance of the cutting edge of the bucket 6 in a predetermined period from the output of the posture detection device S1. Then, controller 30 calculates an average moving speed of the cutting edge, and sets the average moving speed as a target moving speed. Here, when the excavation attachment is controlled so as to maintain the operation of the excavation attachment in accordance with the operation tendency, the controller 30 may notify the operator that the operation mode is changed from the normal operation mode to the assist mode. Specifically, in order to inform the operator of the change of the operation mode from the normal operation mode to the assist mode, the change may be displayed on a display device or voice output may be performed. Further, the information may be continuously notified while the control is performed so as to maintain the operation of the excavation attachment.

Then, the controller 30 starts controlling the moving direction of the cutting edge of the bucket 6 (step ST 4). For example, the controller 30 derives a movement locus of the cutting edge of the bucket 6 for a predetermined period from the output of the posture detection device S1. Then, the controller 30 sets an average value of angles (angles with respect to the horizontal plane) indicating the moving direction at each sampling time as an angle indicating the target moving direction. The angle of the approximate straight line of the movement locus of the cutting edge of the bucket 6 with respect to the horizontal plane within the predetermined period may be set as the angle indicating the target movement direction. Then, the controller 30 extends and contracts the boom cylinder 7 and the arm cylinder 8 so that the cutting edge of the bucket 6 moves in the target movement direction at the target movement speed.

In this way, the controller 30 generates the target movement direction and the target movement speed so that the movement direction and the movement speed of the cutting edge of the bucket 6 as the working portion can be automatically maintained and controlled regardless of the operation amount of the joystick, and controls the operation of the attachment.

However, the controller 30 may generate the target movement speed from an operation amount of a joystick related to any one of the boom 4, the arm 5, and the bucket 6 without automatically maintaining the movement speed. For example, when it is determined that the cutting edge of the bucket 6 as the working portion is moved in a slope direction (inclined surface direction) or when it is determined that the bucket is moved in the front-rear direction (substantially horizontal direction) of the body, the target moving speed may be generated based on the operation amount of the arm lever. Alternatively, when it is determined that the cutting edge of the bucket 6 is moved in the vertical direction (substantially vertical direction) along the wall surface of the groove according to the operation tendency, the target moving speed may be generated according to the operation amount of the boom lever. In this manner, the controller 30 (for example, the operation tendency determination unit 32) may determine whether or not to generate the target moving speed based on the operation tendency and the operation amount of any one of the joysticks. That is, 1 joystick associated with the target movement speed of the derived working site may be selected from the plurality of joysticks according to the operation tendency. Further, the operation portion may be moved in the movement direction determined by the operation tendency while generating the target movement speed from the determined (selected) operation amount of the joystick.

When it is determined that the respective operation amounts are not held for the predetermined period of time (no in step ST 2), the controller 30 ends the attachment operation control process of this time without setting the target movement speed and the target movement direction. Therefore, the boom cylinder 7 and the arm cylinder 8 are not automatically extended and retracted by the controller 30, but are extended and retracted in accordance with actual operation of the boom lever and the arm lever by the operator.

As a determination method, a change in the position of the bucket 6 with time may be referred to instead of a change in the operation amount with time. In this case, it is determined whether or not the predetermined period has elapsed and the range of fluctuation in the moving direction of the bucket 6 is smaller than the predetermined value and the moving speed is smaller than the predetermined value. Alternatively, it may be determined whether or not the moving speed of the bucket 6 is smaller than a predetermined value over a predetermined period and the fluctuation width of the moving speed of the bucket 6 in the predetermined period is smaller than the predetermined value.

Next, an effect of the accessory operation control process will be described with reference to fig. 7. Fig. 7 shows changes over time in the amount of operation of the boom lever in the raising direction (boom raising operation amount), the amount of operation of the arm lever in the closing direction (arm closing operation amount), the speed of movement of the cutting edge of the bucket 6 (cutting edge speed), and the angle indicating the direction of movement of the cutting edge of the bucket 6 (cutting edge angle). In this example, the operator of the excavator performs a ground cutting operation in which the bucket 6 is moved closer to the body side along the horizontal plane by a combined operation of the boom lever and the arm lever.

Specifically, as shown in fig. 7 (a), the operator of the excavator starts the operation of the boom lever in the lifting direction at time t1, and then continues the operation in the lifting direction by a substantially constant operation amount B1. Then, as shown in fig. 7 (B), the operator starts the operation of the arm lever in the closing direction at time t1, and then continues the operation in the closing direction by a substantially constant operation amount A1.

As shown in fig. 7 (C), the cutting edge speed of the bucket 6 starts to rise at time t1, and then, the substantially constant cutting edge speed V1 is maintained. As shown in fig. 7 (D), the cutting edge angle of the bucket 6 is maintained at a substantially constant cutting edge angle D1 from the time point of time t 1. As a result, the cutting edge of the bucket 6 moves substantially horizontally in the body direction.

When it is determined at time t2 that the predetermined period has elapsed and the boom raising operation amount and the arm closing operation amount are held, controller 30 determines the target moving speed of the cutting edge of bucket 6. For example, when the boom-up operation amount is always smaller than the predetermined operation amount TH1 and the arm-closing operation amount is always smaller than the predetermined operation amount TH2 in the period from time t11 to time t2, the controller 30 determines that the boom-up operation amount and the arm-closing operation amount are maintained for the predetermined period. Then, the average value of cutting edge speed V1 in the period from time t11 to time t2 is set as the target moving speed.

When it is determined at time t2 that the predetermined period has elapsed and the boom raising operation amount and the arm closing operation amount are held, controller 30 determines the target moving direction of the cutting edge of bucket 6. For example, controller 30 sets the average value of cutting edge angle D1 in the period from time t11 to time t2 as an angle indicating the target movement direction.

Then, the controller 30 controls the operation of the excavation attachment so as to maintain the operation of the excavation attachment in accordance with the operation tendency (the cutting speed and the cutting angle) until the release condition is satisfied.

As a result, as shown by the solid line in fig. 7 (a), even when the actual boom raising operation amount is lower than the operation amount B1 and the deviation width thereof gradually increases after the time t2, the boom flow rate control valve 17B receives substantially the same boom raising pilot pressure as when the boom raising operation amount is maintained at the operation amount B1 as shown by the one-dot chain line in fig. 7 (a). This is because, in the present embodiment, the controller 30 automatically controls the cutting tip speed and the cutting tip angle of the bucket 6 in accordance with the command. The hatched area in fig. 7 (a) indicates the extent of deviation between the actual boom raising operation amount and the operation amount B1. The magnitude of the deviation corresponds to a boom raising operation amount corresponding to the automatic extension of the boom cylinder 7 by the controller 30.

The automatic operation amount (the pilot pressure difference before and after the automatic adjustment) of the boom lever for maintaining the set target moving speed of the cutting edge of the bucket 6 and the angle indicating the target moving direction changes depending on the working environment. That is, fig. 7 (a) shows an example in which the boom raising pilot pressure is received substantially the same as when the boom raising operation amount is maintained at the operation amount B1, but the present invention is not limited to this configuration. For example, the boom raising pilot pressure may be adjusted so that the boom raising operation amount increases at a predetermined slope, or so that the boom raising operation amount decreases at a predetermined slope. In the example shown in fig. 4A, the boom raising pilot pressure becomes negative when it becomes lower than zero when it passes through the point X1. In this case, the boom 4 moves in the lowering direction.

As shown by the solid line in fig. 7 (B), even when the actual arm closing operation amount fluctuates up and down near the operation amount A1 after time t2, the arm flow rate control valve 17A receives substantially the same arm closing pilot pressure as when the arm closing operation amount is maintained at the operation amount A1 as shown by the one-dot chain line in fig. 7 (B). This is because, in the present embodiment, the controller 30 automatically controls the cutting tip speed and the cutting tip angle of the bucket 6 according to the command. The hatched area in fig. 7 (B) indicates the extent of deviation between the actual amount of arm closing operation and the amount of operation A1. The deviation width corresponds to an operation amount of the arm lever corresponding to automatic extension and contraction of the arm cylinder 8 by the controller 30.

The automatic operation amount (the pilot pressure difference before and after the automatic adjustment) of the arm lever for maintaining the set target moving speed of the cutting edge of the bucket 6 and the angle indicating the target moving direction changes according to the work environment. That is, fig. 7 (B) shows an example of receiving substantially the same arm closing pilot pressure as when the arm closing operation amount is maintained at the operation amount A1, but the present invention is not limited to this configuration. For example, the arm closing pilot pressure may be adjusted so that the arm closing operation amount increases at a predetermined slope, or so that the arm closing operation amount decreases at a predetermined slope.

As shown in fig. 7 (C), after time t2, the cutting edge speed is maintained constant at cutting edge speed V1, which is the target movement speed. Similarly, as shown in fig. 7 (D), after time t2, the cutting edge angle is maintained constant at a cutting edge angle D1 indicating the target movement direction. The alternate long and short dash lines in fig. 7 (C) and 7 (D) show changes with time when the attachment operation control process is not executed.

In this example, since the actual boom raising operation amount deviates downward from the operation amount B1, when the attachment operation control process is not executed, the cutting edge angle gradually deviates from the cutting edge angle D1 indicating the target movement direction as indicated by the one-dot chain line in fig. 7 (D). This means that the cutting edge position of the bucket 6 becomes deeper and the load of the foundation excavation work becomes larger. As shown by the one-dot chain line in fig. 7 (C), the cutting speed gradually decreases as the load of the work of digging the foundation increases. The controller 30 can avoid such a deviation of the cutting edge angle and a drop in the cutting edge speed by executing the attachment operation control processing. Further, the machined surface can be prevented from becoming an inclined surface rather than a horizontal surface.

With the above configuration, even when the actual boom raising operation amount is not sufficient to bring the bucket 6 closer to the horizontal surface, the operator of the excavator can perform the same operation of the excavation attachment as that performed when the operator performs the operation with the boom raising operation amount just suitable for bringing the bucket 6 closer to the horizontal surface. The same is true for moving the bucket 6 away from the horizontal plane, or for moving the bucket 6 closer to or further away from the slope.

Further, when the operator switches between the rough excavation work requiring no assistance by the controller 30 and the fine excavation work requiring assistance by the controller 30, the operator is not required to perform a special operation or work for enabling or disabling the assistance. Therefore, the operator can freely switch between the rough excavation work and the finish machining work without paying attention to the validation/invalidation of the assist by the controller 30, and can receive the assist by the controller 30 at an appropriate timing. Therefore, the excavator according to the embodiment of the present invention can improve the work efficiency.

Further, the operator of the excavator does not need to be aware of the shortage of the boom raising operation amount and the start of the automatic control by the controller 30, and therefore can obtain a comfortable operation feeling. However, when the boom cylinder 7 is automatically extended and retracted, the controller 30 may transmit this to the operator. For example, an in-vehicle display, an in-vehicle speaker, an LED lamp, or the like may be used to communicate this to the operator. In this case, the operator can recognize that the boom raising operation amount is insufficient, and can use this fact for improvement of the operation technique in the future. The same applies to the case where other hydraulic actuators such as the arm cylinder 8 are automatically operated.

The automatic control by the controller 30 is to realize the automatic control of the operation of the excavation attachment desired by the operator in accordance with the content of the actual combined operation performed by the operator, and is not to allow the automatic control of the operation deviating from the content of the actual combined operation performed by the operator. For example, since the target movement direction and the target movement speed are set according to the content of the actual combined operation performed by the operator, the operation of the excavation attachment by the controller 30 does not largely deviate from the operation desired by the operator. Further, even when the attachment operation control process is being executed, the operator of the excavator can stop the operation of the excavation attachment or cause the excavation attachment to perform another operation at a desired timing because the cancellation condition is satisfied. Therefore, the operation of the excavator is not uncomfortable.

Next, an example of the flow of automatic control by the controller 30 will be described with reference to fig. 8 and 9. Fig. 8 and 9 are block diagrams showing the flow of automatic control by the controller 30. Specifically, fig. 8 and 9 are explanatory diagrams when the controller 30 (for example, the operation tendency determination unit 32) determines which joystick generates the target movement speed, and moves the working site in the movement direction determined according to the operation tendency while generating the target movement speed according to the determined joystick.

When the automatic control is started, as shown in fig. 8, the controller 30 calculates three-dimensional coordinates (Xer, yre, zer) of the cutting edge position after the elapse of the unit time from the cutting edge target moving speed, the cutting edge target moving direction, and the three-dimensional coordinates (Xe, ye, ze) of the cutting edge position of the current bucket 6.

The operation tendency determination unit 32 of the controller 30 determines whether or not each operation amount is held for a predetermined period based on the operation amount of the joystick. The operation tendency determination unit 32 may receive an input of the cutting edge position of the bucket 6 as the working site, and determine whether or not the operation of the cutting edge position of the bucket 6 is maintained so as to be a constant operation over a predetermined period. When it is determined that each operation amount is held for a predetermined period, operation tendency determination unit 32 generates a cutting edge target movement speed.

The cutting edge target movement speed is generated, for example, from the operation tendency. The direction in which the cutting edge target moves is determined, for example, by a joystick operation. The operation tendency is determined based on, for example, the joystick operation amount. The current cutting edge position is determined, for example, by the boom rotation angle β ₁ Angle of rotation beta of bucket arm ₂ And bucket rotation angle beta ₃ And then calculated. The unit time is, for example, a time corresponding to an integral multiple of the control cycle. In this embodiment, the value of the Y coordinate of the cutting edge position is not changed before and after the movement. That is, the value Yer of the Y coordinate of the cutting edge position after the elapse of the unit time is the same as the value Ye of the Y coordinate of the current cutting edge position. In the present embodiment, controller 30 determines the movement path of the blade tip position after the start of control. That is, the coordinate value of the cutting edge position at each time point per unit time in the future is determined. However, controller 30 may recalculate the coordinate values of the cutting edge position at 1 or more future points per unit time.

When the moving direction and the moving speed of the cutting edge of the bucket 6 as the working portion are automatically controlled regardless of the operation amount of the joystick, the controller 30 may generate the target moving direction and the target moving speed in the operation tendency determination unit 32.

When the operation tendency determination unit 32 does not determine that each operation amount is held for a predetermined period, the flow rate control valve in the control valve 17 corresponding to each hydraulic actuator operates in accordance with the lever operation amount.

Then, controller 30 generates command value β related to the turning operation of boom 4, arm 5, and bucket 6 based on calculated value xr of the X coordinate and value Zer of the Z coordinate _1r 、β _2r 、β _3r . Command value beta _1r For example, the rotation angle of the boom 4 when the cutting edge position can be aligned to the three-dimensional coordinates (Xer, yre, zer). With respect to command value beta _2r And a command value beta _3r The same applies.

The controller 30 generates a command value using, for example, a predetermined calculation formula. In the present embodiment, controller 30 calculates command value β when the cutting edge position can be aligned to the three-dimensional coordinates (Xer, yer, zer) using equations (1) and (2) described above _1r 、β _2r 、β _3r . Based on the command value beta of the X coordinate value xer and the Z coordinate value Zer _1r 、β _2r 、β _3r Of the function of (c). In this case, the controller 30 rotates the bucket by an angle β, for example ₃ Is set to be constant and make the rotating angle beta of the moving arm ₁ And bucket arm rotation angle beta ₂ Calculating the command value beta on the premise of the change of the two _1r 、β _2r 、β _3r . However, the controller 30 may calculate the command value β under other conditions _1r 、β _2r 、β _3r . Alternatively, controller 30 may refer to a position of a cutting edge and a boom rotation angle β stored in advance ₁ Bucket rod rotation angle beta ₂ And bucket rotation angle beta ₃ A table of relationships between generates command values.

Then, as shown in fig. 9, the controller 30 rotates the boom by the boom rotation angle β ₁ Angle of rotation beta of bucket arm ₂ And bucket rotation angle beta ₃ The respective measured values are the generated command values beta _1r 、β _2r 、β _3r In such a manner thatThe boom 4, the arm 5, and the bucket 6 operate. In this case, the controller 30 may derive the and command value β using equations (3) to (5) _1r 、β _2r 、β _3r Corresponding command value alpha _1r 、α _2r 、α _3r . Further, the controller 30 may use the angle α that is the output of the boom angle sensor, arm angle sensor, and bucket angle sensor ₁ 、α ₂ 、α ₃ Becomes the derived command value alpha _1r 、α _2r 、α _3r The boom 4, the arm 5, and the bucket 6 are operated in the above-described manner.

Specifically, controller 30 generates a rotation angle β with respect to the boom ₁ Current value and command value beta of _1r Difference of delta beta ₁ And a corresponding boom cylinder pilot pressure command. Then, a control current corresponding to the boom cylinder pilot pressure command is output to a boom electromagnetic proportional valve as the electromagnetic valve 51. The boom electromagnetic proportional valve causes a pilot pressure corresponding to a control current corresponding to the boom cylinder pilot pressure command to act on the boom flow rate control valve 17B.

Then, the boom flow control valve 17B, which receives the pilot pressure generated by the boom solenoid proportional valve, supplies the hydraulic oil discharged from the main pump 14 to the boom cylinder 7 in a flow direction and at a flow rate corresponding to the pilot pressure. The boom cylinder 7 expands and contracts by the hydraulic oil supplied through the boom flow rate control valve 17B. The boom angle sensor detects an angle α of the boom 4 operated by the telescopic boom cylinder 7 ₁ 。

Then, the controller 30 compares the angle α detected by the boom angle sensor ₁ Substituting the formula (3) and calculating the rotation angle beta of the movable arm ₁ . Further, the boom rotation angle β used when the boom cylinder pilot pressure command is generated ₁ The calculated value is fed back.

The above description is based on the command value β _1r The operation of the boom 4 is described, but based on the command value β _2r The operation of the arm 5 and the operation based on the command value beta _3r The same applies to the operation of the bucket 6. Thus, with respect to the command-based value β _2r Operation of arm 5 andbased on the command value beta _3r The flow of the operation of the bucket 6 in (2) is not described.

As shown in fig. 8, the controller 30 may use the pump discharge amount derivation parts CP1, CP2, and CP3 to derive the command value β from the command value β _1r 、β _2r 、β _3r The discharge amount of the pump is led out. In the present embodiment, the pump discharge amount derivation parts CP1, CP2, and CP3 use a table or the like registered in advance and derive the command value β from the command value β _1r 、β _2r 、β _3r The pump discharge amount is derived. The total pump discharge amounts derived by the pump discharge amount derivation sections CP1, CP2, and CP3 are input to the pump flow rate calculation section as the total pump discharge amount. The pump flow rate calculation unit controls the discharge rate of main pump 14 based on the total pump discharge rate that is input. In the present embodiment, the pump flow rate calculation unit controls the discharge rate of the main pump 14 by changing the swash plate tilt angle of the main pump 14 in accordance with the total pump discharge rate.

In this way, the controller 30 can simultaneously perform opening control of the boom flow rate control valve 17B, the arm flow rate control valve 17A, and the bucket flow rate control valve and control of the discharge amount of the main pump 14. Therefore, an appropriate amount of hydraulic oil can be supplied to each of the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9.

In this way, the controller 30 calculates the three-dimensional coordinates (Xer, yer, zer), and instructs the value β _1r 、β _2r 、β _3r Is set to 1 control cycle, and automatic control is executed by repeating the control cycles. Further, the controller 30 can improve the accuracy of automatic control by feedback-controlling the cutting edge position based on the output of the posture detection device S1. Specifically, the accuracy of automatic control can be improved by feedback-controlling the flow rates of the hydraulic oil flowing into the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 based on the output of the posture detection device S1.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments. The above embodiment can be applied to various modifications, replacements, and the like without departing from the scope of the present invention. Further, the features described separately can be combined as long as technically contradictory features do not occur.

For example, in the above-described embodiment, the hydraulic operation device is used as the operation device 26, but an electric operation device may be used. Fig. 10 shows a configuration example of an operation system including an electric operation device. Specifically, the operation system of fig. 10 is an example of a boom operation system, and is mainly configured by a pilot pressure operation type control valve 17, a boom lever 26B as an electrical lever, a controller 30, a boom raising operation solenoid valve 60, and a boom lowering operation solenoid valve 62. The operation system of fig. 10 is similarly applicable to an arm operation system, a bucket operation system, and the like.

The pilot pressure operation type control valve 17 includes an arm flow control valve 17A (see fig. 3), a boom flow control valve 17B (see fig. 3), a bucket flow control valve, and the like. The solenoid valve 60 is configured to be able to adjust the flow passage area of an oil passage connecting the pilot pump 15 and the left (lift-side) pilot port of the boom flow rate control valve 17B. The solenoid valve 62 is configured to be able to adjust the flow passage area of the oil passage connecting the pilot pump 15 and the right (lower) pilot port of the boom flow rate control valve 17B.

When a manual operation is performed, the controller 30 generates a boom-up operation signal (electrical signal) or a boom-down operation signal (electrical signal) based on an operation signal (electrical signal) output from the operation signal generating portion of the boom lever 26B. The operation signal output from the operation signal generating unit of the boom lever 26B is an electrical signal that changes in accordance with the operation amount and the operation direction of the boom lever 26B.

Specifically, when the boom lever 26B is operated in the boom raising direction, the controller 30 outputs a boom raising operation signal (electrical signal) corresponding to the lever operation amount to the solenoid valve 60. The solenoid valve 60 adjusts the flow path area in accordance with a boom raising operation signal (electrical signal), and controls the pilot pressure acting on the left (lift side) pilot port of the boom flow rate control valve 17B. Similarly, when the boom lever 26B is operated in the boom-down direction, the controller 30 outputs a boom-down operation signal (electrical signal) corresponding to the lever operation amount to the electromagnetic valve 62. The solenoid valve 62 adjusts the flow path area in accordance with a boom lowering operation signal (electrical signal), and controls the pilot pressure acting on the right (lowering side) pilot port of the boom flow rate control valve 17B.

When the automatic control is executed, the controller 30 generates a boom-up operation signal (electrical signal) or a boom-down operation signal (electrical signal) from the correction operation signal (electrical signal) in place of the operation signal output from the operation signal generating portion of the boom lever 26B. The correction operation signal may be an electrical signal generated by the controller 30, or may be an electrical signal generated by an external control device or the like other than the controller 30.

Fig. 11 shows another configuration example of an operation system including an electric operation device. Specifically, the operation system of fig. 11 is another example of a boom operation system, and is mainly configured by the solenoid-operated control valve 17, a boom lever 26B as an electric lever, and a controller 30. The operation system of fig. 11 is also applicable to an arm operation system, a bucket operation system, and the like.

The solenoid-operated control valve 17 includes a boom flow rate control valve, an arm flow rate control valve, a bucket flow rate control valve, and the like, each of which is configured by a solenoid spool valve that operates in response to a command from the controller 30.

The boom manipulation system of fig. 11 is different from the boom manipulation system of fig. 10 in that the controller 30 directly controls the boom flow rate control valve. In the boom operation system of fig. 10, the controller 30 is configured to indirectly control the boom flow rate control valve 17B (see fig. 3) via the solenoid valve 60 or the solenoid valve 62.

In the configuration of fig. 11, when a manual operation is performed, the controller 30 generates a boom operation signal (electrical signal) based on an operation signal (electrical signal) output from an operation signal generating unit of the boom lever 26B.

Specifically, when the boom lever 26B is operated in the boom raising direction, the controller 30 outputs a boom raising operation signal (electrical signal) corresponding to the lever operation amount to the boom flow rate control valve. The boom flow rate control valve adjusts the flow rate of the hydraulic oil flowing into the bottom side oil chamber of the boom cylinder 7 by shifting only the spool stroke amount in accordance with the boom raising operation signal (electrical signal). Similarly, when the boom lever 26B is operated in the boom-down direction, the controller 30 outputs a boom-down operation signal (electrical signal) corresponding to the lever operation amount to the boom flow rate control valve. The boom flow rate control valve adjusts the flow rate of the hydraulic oil flowing into the rod side oil chamber of the boom cylinder 7 by shifting only the spool stroke amount in accordance with the boom lowering operation signal (electrical signal).

When the automatic control is executed, the controller 30 generates a boom-up operation signal (electrical signal) or a boom-down operation signal (electrical signal) from the correction operation signal (electrical signal) instead of the operation signal output from the operation signal generating part of the boom manipulating lever 26B. The correction operation signal may be an electrical signal generated by the controller 30, or may be an electrical signal generated by an external control device or the like other than the controller 30.

In this way, even when the electric operation device is used, the excavator according to the embodiment of the present invention can operate in the same manner as when the hydraulic operation device is used.

Description of the symbols

1-lower traveling body, 1L-left traveling hydraulic motor, 1R-right traveling hydraulic motor, 2-slewing mechanism, 2A-slewing hydraulic motor, 3-upper slewing body, 4-boom, 5-arm, 6-bucket, 7-boom cylinder, 8-arm cylinder, 9-bucket cylinder, 10-cab, 11-engine, 13-regulator, 14-main pump, 15-pilot pump, 17-control valve, 17A-flow control valve for arm, 17B-flow control valve for boom, 17L-left pilot port, 17R-right pilot port, 26-operating device, 26A-arm lever, 26B-boom lever, 29-pressure sensor, 29L, 29R-pilot pressure sensor, 30-controller, 31-attachment control portion, 32-operation tendency determination portion, 50-adjustment mechanism, 51, 52L, 52R-solenoid valve, 60, 62-solenoid valve, C1-C4, C11, C12, C21, C22-pipeline.

Claims

1. A shovel is provided with: a lower traveling body; an upper slewing body mounted on the lower traveling body; an attachment mounted to the upper slewing body; and a control device for controlling the operation of the attachment device operated by the composite operation of the joystick, wherein the control device derives an operation tendency based on the content of the composite operation performed by the operator within a predetermined period, determines a moving direction of the attachment device in accordance with the operation tendency, and controls the operation of the attachment device so as to automatically maintain the determined moving direction.

2. The shovel of claim 1, wherein the operational tendency is derived from a speed and direction of movement of the termination attachment within the predetermined period of time as detected by the attitude detection device.

3. The shovel according to claim 1, wherein the control unit grasps the operation content of the joystick based on the pilot pressure generated by the joystick, and controls the operation of the attachment so as to maintain the operation of the attachment in accordance with the operation tendency when the operation amount of each of at least 2 joysticks is maintained for the predetermined period.

4. The shovel according to claim 2, wherein the control device grasps the operation content of the joystick based on the movement speed and the movement direction of the terminal attachment detected by the attitude detection device, and controls the operation of the attachment so as to maintain the operation of the attachment in accordance with the operation tendency when the movement speed and the movement direction of the terminal attachment are maintained for the predetermined period.

5. The shovel of claim 1, wherein the control device notifies an operator of controlling the operation of the attachment in a manner that maintains the operation of the attachment in accordance with the operation tendency.

6. The shovel according to claim 1, wherein the control device controls the operation of the attachment so as to correspond to a moving speed and a moving direction of the working portion derived from the operation tendency.

7. The shovel according to claim 1, wherein the control device controls the operation of the attachment so as to correspond to a moving direction of a working portion derived from the operation tendency and a moving speed of the working portion derived from an operation amount of a joystick.

8. The shovel according to claim 7, wherein the control device selects 1 joystick associated with deriving a moving speed of the working site from a plurality of joysticks according to the operation tendency.

9. The shovel according to claim 8, wherein the control device selects a boom lever when it is determined that the working site is moved in the vertical direction.

10. The shovel of claim 8, wherein the control device selects a stick lever when it is determined to move the work site in a sloping direction or in a horizontal direction.