Shovel

Abstract

To provide a shovel capable of realizing smooth movement of an attachment.SOLUTION: A shovel 100 includes a lower traveling body 1, an upper rotating body 3 rotatably mounted on the lower traveling body 1, an attachment AT including a boom 4 and an arm 5 attached to the upper rotating body 3, and a controller 30 that operates the boom 4 and the arm 5 to move a tip 6a of a bucket 6 along a preset target trajectory. The controller 30 is configured to determine respective target operating speeds of the boom 4 and the arm 5 based on a target moving speed of the tip 6a of the bucket 6 on the target trajectory.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an excavator.

Background Art

[0002] Conventionally, there is known an excavator that automatically expands and contracts a boom cylinder so that the target construction surface and the tip of the bucket claw coincide when an operator manually performs an arm closing operation to expand and contract an arm cylinder (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, depending on the relationship between the posture of the attachment including the boom and the arm and the target construction surface, it is difficult for the above-described excavator to realize a telescoping speed of the boom cylinder corresponding to the telescoping speed of the arm cylinder, and there is a possibility that smooth movement of the attachment cannot be realized.

[0005] Therefore, it is desirable to provide an excavator that can realize smooth movement of the attachment.

Means for Solving the Problems

[0006] The excavator according to an embodiment of the present disclosure includes a lower traveling body, an upper revolving body rotatably mounted on the lower traveling body, an attachment including a boom and an arm attached to the upper revolving body, and a control device configured to operate the boom and the arm so as to move a predetermined portion of the attachment along a preset target trajectory. The control device determines respective target operating speeds of the boom and the arm based on a target moving speed of the predetermined portion of the attachment on the target trajectory.

Advantages of the Invention

[0007] The above-described excavator can achieve smooth movement of the attachment.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. FIG. 1 is a side view of an excavator 100 as an example of a construction machine according to an embodiment of the present disclosure. FIG. 2 is a diagram showing a configuration example of the drive system of the excavator 100 in FIG. 1. In FIG. 2, the mechanical power system is indicated by a double line, the hydraulic oil line is indicated by a thick solid line, the pilot line is indicated by a broken line, and the electric drive / control system is indicated by a thin solid line, respectively.

[0010] As shown in FIG. 1, an upper swing body 3 is swingably mounted on a lower traveling body 1 of the excavator 100 via a swing mechanism 2. A boom 4 as a working tool is attached to the upper swing body 3. An arm 5 as a working tool is attached to the tip of the boom 4, and an end attachment as a working tool is attached to the tip of the arm 5. In the illustrated example, a bucket 6 is attached as an end attachment to the tip of the arm 5, but a grapple, a breaker, or a lifting magnet, etc. may be attached as an end attachment to the tip of the arm 5.

[0011] The boom 4, the arm 5, and the bucket 6 constitute an excavation attachment which is an example of the attachment AT. And the boom 4 is driven by a boom cylinder 7, the arm 5 is driven by an arm cylinder 8, and the bucket 6 is driven by a bucket cylinder 9. A boom angle sensor S1 is attached to the boom 4, an arm angle sensor S2 is attached to the arm 5, and a bucket angle sensor S3 is attached to the bucket 6.

[0012] The boom angle sensor S1 is a sensor that detects the rotation angle of the boom 4. In the illustrated example, the boom angle sensor S1 is an acceleration sensor that detects the inclination angle of the boom 4 with respect to the horizontal plane by detecting the acceleration due to gravity. In the illustrated example, the boom angle sensor S1 detects the rotation angle of the boom 4 around the boom foot pin that connects the upper swing body 3 and the boom 4 as the boom angle.

[0013] The arm angle sensor S2 is a sensor that detects the rotation angle of the arm 5. In the illustrated example, the arm angle sensor S2 is an acceleration sensor that detects the tilt angle of the arm 5 with respect to the horizontal plane by detecting the acceleration due to gravity. In the illustrated example, the arm angle sensor S2 detects the rotation angle of the arm 5 around the arm pin that connects the boom 4 and the arm 5 as the arm angle.

[0014] The bucket angle sensor S3 is a sensor that detects the rotation angle of the bucket 6. In the illustrated example, the bucket angle sensor S3 is an acceleration sensor that detects the tilt angle of the bucket 6 with respect to the horizontal plane by detecting the acceleration due to gravity. In the illustrated example, the bucket angle sensor S3 detects the rotation angle of the bucket 6 around the bucket pin that connects the arm 5 and the bucket 6 as the bucket angle.

[0015] At least one of the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 may be a potentiometer using a variable resistor, a stroke sensor that detects the stroke amount of the corresponding hydraulic cylinder, or a rotary encoder that detects the rotation angle around the connecting pin, etc. Alternatively, at least one of the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 may be an inertial measurement device that combines an acceleration sensor and an angular velocity sensor (gyro sensor). The boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 function as an attitude detection device PS for detecting the attitude of the attachment AT.

[0016] The upper swing body 3 is provided with a cabin 10 and is equipped with a drive source 11 and the like. Further, a body tilt sensor S4, a swing angular velocity sensor S5, and a positioning device S6 are attached to the upper swing body 3. An operation device 26, a controller 30, and the like are mounted in the cabin 10.

[0017] The controller 30 is an example of a control device, configured to receive information from an information acquisition device, execute various calculations, and output a control command based on the calculation result to the drive control device 50. In the illustrated example, the controller 30 is composed of an arithmetic processing device (processing circuit) including a CPU and a storage device, etc., and performs drive control of the excavator 100. Various functions of the controller 30 are realized by the CPU executing a program stored in the storage device.

[0018] The information acquisition device includes, for example, a load detection device LS, an attitude detection device PS, a positioning device S6, an operation mode switching device SW, an operation content detection device 29, a spatial recognition device such as a camera or LIDAR, an input device such as a membrane switch or a touch panel, a communication device, or an external storage device, etc.

[0019] The drive control device 50 is a device for controlling the movement of an actuator that drives each part of the excavator 100, and includes a solenoid valve, etc. The actuator includes at least one of an electric actuator and a hydraulic actuator. The hydraulic actuator includes a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, etc. The electric actuator may be a slewing electric motor.

[0020] In the illustrated example, the controller 30 is configured to execute a function of assisting the manual operation of the excavator 100 by the operator. Hereinafter, this function is referred to as the "machine control function". In the machine control function, the controller 30, for example, in order to move a predetermined part of the attachment AT along a preset target trajectory, when a manual operation is performed on at least one of the left traveling hydraulic motor 1L, the right traveling hydraulic motor 1R, the slewing hydraulic motor 2A, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 by the operator, automatically operates at least one of the left traveling hydraulic motor 1L, the right traveling hydraulic motor 1R, the slewing hydraulic motor 2A, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 so that the predetermined part of the attachment AT follows the target trajectory. For example, when the operator is performing an arm closing operation, the controller 30 automatically extends the boom cylinder 7 to raise the boom 4. Note that the controller 30 may automatically extend the arm cylinder 8 at an extension speed greater than the extension speed corresponding to the operation amount of the arm operation lever when the operator is performing an arm closing operation, stop the expansion and contraction of the arm cylinder 8, and expand and contract the hydraulic cylinders other than the arm cylinder 8. Note that the target trajectory may be dynamically calculated when the operating device 26 is manually operated. Further, the predetermined part of the attachment AT is, for example, the tip 6a of the bucket 6, a predetermined part or a predetermined point on the back surface of the bucket 6, a bucket pin, an arm top pin, or a boom top pin, etc.

[0021] The controller 30 may execute a function of automatically operating the excavator 100. Hereinafter, this function is referred to as the "autonomous control function". In the autonomous control function, the controller 30, for example, in order to move a predetermined part of the attachment AT along a preset target trajectory, may automatically operate at least one of the boom 4, the arm 5, and the bucket 6. Specifically, when the operator is not performing a manual operation, the controller 30 may automatically operate the boom 4, the arm 5, and the bucket 6 so that the predetermined part of the attachment AT follows the target trajectory.

[0022] Note that the machine control function may be used in a remotely operated excavator that is remotely operated using an operating device located outside the excavator 100. Further, the autonomous control function may be used in an autonomous excavator that does not have an operating device.

[0023] The body tilt sensor S4 is a sensor that detects the tilt angle of the upper swing body 3 with respect to the horizontal plane. In the illustrated example, it is an acceleration sensor that detects the tilt angle of the front-rear axis of the upper swing body 3 with respect to the horizontal plane (hereinafter referred to as the "body pitch angle") and the tilt angle of the left-right axis of the upper swing body 3 with respect to the horizontal plane (hereinafter referred to as the "body roll angle") by detecting the acceleration due to gravity. Note that the body tilt sensor S4 may constitute an attitude detection device PS for detecting the attitude of the attachment AT.

[0024] The swing angular velocity sensor S5 is a sensor that detects the angular velocity of the upper swing body 3 that swings (rotates) around the swing axis. In the illustrated example, the swing angular velocity sensor S5 is a rotary encoder that detects the angular velocity of the upper swing body 3. Note that the swing angular velocity sensor S5 may constitute an attitude detection device PS for detecting the attitude of the attachment AT.

[0025] The positioning device S6 is a device that measures the position of the excavator 100. In the illustrated example, the positioning device S6 is an electronic compass including two GNSS receivers, and outputs information regarding the position coordinates (latitude, longitude, altitude) and orientation (azimuth) of the positioning device S6 in the world geodetic system to the controller 30. The world geodetic system is a three-dimensional orthogonal XYZ coordinate system with the origin at the center of gravity of the earth, the X-axis in the direction of the intersection of the Greenwich meridian and the equator, the Y-axis in the direction of 90 degrees east longitude, and the Z-axis in the direction of the North Pole.

[0026] The drive source 11 is a drive source of the excavator 100, and is, for example, a diesel engine, a hydrogen engine, an electric motor, or the like. In the illustrated example, the drive source 11 is a diesel engine that employs isochronous control to maintain a constant engine speed regardless of the increase or decrease of the load.

[0027] A main pump 14 and a pilot pump 15 as hydraulic pumps are connected to the drive source 11. The main pump 14 is connected to a control valve unit 17 via a hydraulic oil line.

[0028] The control valve unit 17 is a hydraulic control device that controls the hydraulic system of the excavator 100. In the illustrated example, the control valve unit 17 includes a plurality of control valves 170 that are spool valves corresponding to respective ones of a plurality of hydraulic actuators such as a left travel hydraulic motor 1L, a right travel hydraulic motor 1R, a boom cylinder 7, an arm cylinder 8, a bucket cylinder 9, and a swing hydraulic motor 2A. Each of the plurality of hydraulic actuators is connected to a corresponding control valve 170 in the control valve unit 17 via a hydraulic oil line.

[0029] An operating oil line connected to the bottom-side oil chamber of the boom cylinder 7 is provided with a boom bottom pressure sensor S7B, and an operating oil line connected to the rod-side oil chamber of the boom cylinder 7 is provided with a boom rod pressure sensor S7R. An operating oil line connected to the bottom-side oil chamber of the arm cylinder 8 is provided with an arm bottom pressure sensor S8B, and an operating oil line connected to the rod-side oil chamber of the arm cylinder 8 is provided with an arm rod pressure sensor S8R. An operating oil line connected to the bottom-side oil chamber of the bucket cylinder 9 is provided with a bucket bottom pressure sensor S9B, and an operating oil line connected to the rod-side oil chamber of the bucket cylinder 9 is provided with a bucket rod pressure sensor S9R. An operating oil line connected to the first port of the left traveling hydraulic motor 1L is provided with a first left traveling pressure sensor S10F, and an operating oil line connected to the second port of the left traveling hydraulic motor 1L is provided with a second left traveling pressure sensor S10S. An operating oil line connected to the first port of the right traveling hydraulic motor 1R is provided with a first right traveling pressure sensor S11F, and an operating oil line connected to the second port of the right traveling hydraulic motor 1R is provided with a second right traveling pressure sensor S11S. An operating oil line connected to the first port of the slewing hydraulic motor 2A is provided with a first slewing pressure sensor S12F, and an operating oil line connected to the second port of the slewing hydraulic motor 2A is provided with a second slewing pressure sensor S12S. An operating oil line connected to the discharge port of the main pump 14 is provided with a discharge pressure sensor S13.

[0030] At least one of the boom bottom pressure sensor S7B, the boom rod pressure sensor S7R, the arm bottom pressure sensor S8B, the arm rod pressure sensor S8R, the bucket bottom pressure sensor S9B, the bucket rod pressure sensor S9R, the first left travel pressure sensor S10F, the second left travel pressure sensor S10S, the first right travel pressure sensor S11F, the second right travel pressure sensor S11S, the first swing pressure sensor S12F, the second swing pressure sensor S12S, and the discharge pressure sensor S13 functions as a load detection device LS for detecting the magnitude of the working load of the excavator 100. The load detection device LS is connected to the controller 30. In FIG. 2, for clarity, the illustration of the thin solid line representing the electric drive and control system connecting the load detection device LS and the controller 30 is omitted.

[0031] The pilot pump 15 is configured to be able to supply hydraulic oil to the pilot ports of the plurality of control valves 170 in the control valve unit 17 via the pilot line 25. In the illustrated example, the pilot pump 15 is a fixed displacement hydraulic pump. Note that the pilot pump 15 may be omitted. In this case, the function performed by the pilot pump 15 may be realized by the main pump 14. That is, the main pump 14 may have a function of supplying hydraulic oil to the hydraulic control device after reducing the pressure of the hydraulic oil by means of a throttle or the like, in addition to the function of supplying hydraulic oil to the control valve unit 17.

[0032] The operating device 26 is a device for operating the excavator 100 and includes a lever, a pedal, a switch, a button, or a dial, etc. In the illustrated example, the operating device 26 includes a left operating lever that functions as an arm operating lever and a swing operating lever, a right operating lever that functions as a boom operating lever and a bucket operating lever, a central operating lever that functions as a travel lever, and a central operating pedal that functions as a travel pedal.

[0033] The operation content detection device 29 is a device that detects the operation content of the operation device 26 and outputs the detection value to the controller 30. The operation content of the operation device 26 is the lever operation angle, lever operation direction, etc. In the illustrated example, the operation content detection device 29 is an operation angle sensor that detects the operation angle of the lever that constitutes the electric operation device as the operation device 26. However, when the operation device 26 is a hydraulic operation device (a device that generates pilot pressure), the operation content detection device 29 may be a pilot pressure sensor.

[0034] The operation mode switching device SW is a device for switching the operation mode of the excavator 100. The operation modes include, for example, a manual operation mode, a semi-automatic operation mode, and a full-automatic operation mode, etc. The full-automatic operation mode may be omitted. In the illustrated example, the operation mode switching device SW is a push-button type mode switch provided at the tip of the left operation lever. When the mode switch is pressed, the semi-automatic operation mode is selected, and when the mode switch is not pressed, the manual operation mode is selected. When the manual operation mode is selected, the controller 30 operates the actuator corresponding to the manual operation according to the operator's manual operation on the operation device 26. For example, when the arm operation lever is operated, the controller 30 extends and retracts the arm cylinder 8 according to the operation direction and operation amount of the arm operation lever. On the other hand, when the semi-automatic operation mode is selected, the controller 30 executes the machine control function and operates one or more actuators to move a predetermined part of the attachment AT along a preset target trajectory according to the operator's manual operation on the operation device 26. For example, when the arm operation lever is operated, the controller 30 operates at least one of the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 according to the operation direction and operation amount of the arm operation lever, and moves the tip 6a of the bucket 6 along a preset target trajectory.

[0035] Next, a configuration example of the controller 30 will be described. The controller 30 is configured to receive a signal output by the information acquisition device, execute various calculations, and output a control command to the drive control device 50. Specifically, the controller 30 includes a position calculation unit 30A, a trajectory generation unit 30B, and an automatic control unit 30C as functional elements. Each functional element may be configured by hardware, software, or a combination of hardware and software. The position calculation unit 30A, the trajectory generation unit 30B, and the automatic control unit 30C are shown separately for convenience of explanation, but do not necessarily need to be physically separated, and may be configured by common software components, hardware components, or a combination thereof, either wholly or partially.

[0036] The position calculation unit 30A is configured to calculate the position of the positioning target. In the present embodiment, the position calculation unit 30A calculates the coordinate points in the reference coordinate system of one or more predetermined parts in the attachment AT. In the illustrated example, the predetermined part is the tip 6a of the bucket 6. The reference coordinate system is a coordinate system based on the excavator 100. For example, it is a three-dimensional orthogonal coordinate system with the extending direction of the attachment AT as the X axis and the swing axis of the excavator 100 as the Z axis. The positional relationship between the origin coordinates of the reference coordinate system and the coordinates of the mounting position of the positioning device S6 (hereinafter referred to as "positioning device coordinates") is relatively invariant. Therefore, the position calculation unit 30A can uniquely derive the origin coordinates of the reference coordinate system in the world geodetic system from the respective detection values of the body tilt sensor S4 and the positioning device S6. The origin of the reference coordinate system is, for example, the intersection of the swing axis and the ground contact surface of the excavator 100. The ground contact surface of the excavator 100 is, for example, a virtual plane corresponding to the ground on which the lower traveling body 1 contacts. The reference coordinate system is, for example, an XYZ orthogonal coordinate system, having an X axis parallel to the longitudinal axis of the lower traveling body 1, a Y axis parallel to the lateral axis of the lower traveling body 1, and a Z axis parallel to the swing axis of the excavator 100.

[0037] In the figure example, the position calculation unit 30A derives the origin coordinates (latitude, longitude, altitude) of the reference coordinate system based on the detection values of the aircraft tilt sensor S4 and the positioning device S6 respectively. Specifically, the position calculation unit 30A derives the origin coordinates of the reference coordinate system in the World Geodetic System based on the position coordinates and azimuth of the positioning device S6 in the World Geodetic System, which are the detection values of the positioning device S6.

[0038] Also, the position calculation unit 30A derives a rotation matrix for aligning the three axes of the reference coordinate system with the three axes of the World Geodetic System by rotating the reference coordinate system based on the aircraft roll angle and aircraft pitch angle, which are the detection values of the aircraft tilt sensor S4. Thereby, if the coordinates of an arbitrary point in the reference coordinate system are determined, the position calculation unit 30A can derive the coordinates of that arbitrary point in the World Geodetic System based on the origin coordinates of the reference coordinate system in the World Geodetic System and the rotation matrix.

[0039] Note that the position calculation unit 30A may be configured to derive the coordinates in the World Geodetic System of a predetermined part on the upper slewing body 3 such as the boom foot pin based on the detection value of the positioning device S6 without using the detection value of the aircraft tilt sensor S4. In this case, the aircraft tilt sensor S4 may be omitted.

[0040] Also, the position calculation unit 30A derives the posture of the attachment AT based on the detection values of the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 respectively. This is to enable derivation of the coordinates in the reference coordinate system corresponding to each point on the attachment AT, and ultimately to enable derivation of the coordinates in the World Geodetic System corresponding to each point. With this configuration, the controller 30 can recognize, for example, the positional relationship between the coordinates of a predetermined part of the attachment AT and the coordinates on the target trajectory in the World Geodetic System.

[0041] The trajectory generation unit 30B is configured to generate a target trajectory, which is a trajectory followed by a predetermined part of the attachment AT. In the illustrated example, the trajectory generation unit 30B generates a target trajectory to be used when the automatic control unit 30C automatically operates the actuator. Specifically, the trajectory generation unit 30B generates a target trajectory based on, for example, data related to a target construction surface (target construction surface data) such as a design surface stored in a storage device such as a volatile storage device or a non-volatile storage device in the controller 30. The target construction surface data is data expressed using coordinates in, for example, the World Geodetic System. The trajectory generation unit 30B may generate a target trajectory based on information about the terrain around the excavator 100 acquired by a space recognition device such as a camera or LIDAR (not shown) mounted on the excavator 100. Alternatively, the trajectory generation unit 30B may derive information about the past trajectory of a predetermined part from the past output of the posture detection device PS stored in the storage device and generate a target trajectory based on that information. Alternatively, the trajectory generation unit 30B may generate a target trajectory based on the current position of a predetermined part of the attachment AT and the target construction surface data.

[0042] The automatic control unit 30C is configured to be able to automatically operate the actuator. In the illustrated example, the automatic control unit 30C is configured to execute a machine control function and assist the operator's manual operation of the excavator by automatically operating the actuator when a predetermined start condition is satisfied.

[0043] Specifically, when the arm operation lever is operated while a mode switch, which is an example of the operation mode switching device SW, is pressed, the automatic control unit 30C automatically operates the actuator so that a predetermined part of the attachment AT moves along the target trajectory.

[0044] More specifically, when the operator tilts the arm operation lever in the arm closing direction while pressing the mode switch with the thumb, the automatic control unit 30C automatically expands and contracts at least one of the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 so that the target trajectory generated by the trajectory generation unit 30B matches the position of the tip 6a of the bucket 6.

[0045] Further, the automatic control unit 30C can automatically operate each actuator by giving a control command (current command) to the drive control device 50 (for example, a solenoid valve) corresponding to each actuator and individually adjusting the pilot pressure acting on the control valve 170 corresponding to each actuator. For example, the automatic control unit 30C can operate at least one of the boom cylinder 7 and the bucket cylinder 9 regardless of whether the right operation lever is tilted.

[0046] Next, with reference to FIG. 3, a configuration example of the drive control device 50 will be described. FIG. 3 is a schematic diagram of a hydraulic circuit related to a hydraulic actuator. Specifically, FIG. 3 is a schematic diagram of a hydraulic circuit related to the arm cylinder 8. The following description with reference to FIG. 3 is related to the arm cylinder 8, but is similarly applicable to other hydraulic actuators such as the left traveling hydraulic motor 1L, the right traveling hydraulic motor 1R, the slewing hydraulic motor 2A, the boom cylinder 7, and the bucket cylinder 9.

[0047] As shown in FIG. 3, the hydraulic circuit related to the hydraulic actuator includes a drive control device 50 that receives a control command (current command) from the controller 30. The drive control device 50 is an electromagnetic proportional valve and operates according to the control command output by the automatic control unit 30C of the controller 30. Therefore, the controller 30 can supply the pilot oil discharged by the pilot pump 15 through the drive control device 50 that utilizes the pilot oil, either in response to the operation of the operating device 26 by the operator or independently of the operation of the operating device 26 by the operator, to the pilot port of the corresponding control valve 170 in the control valve unit 17. And the controller 30 can make the pilot pressure generated (regulated) by the drive control device 50 act on the pilot port of the corresponding control valve 170.

[0048] Specifically, the drive control device 50 includes an arm solenoid valve 50A, and the arm solenoid valve 50A includes a left arm solenoid valve 50AL and a right arm solenoid valve 50AR. The arm solenoid valve 50A is arranged in a pipeline connecting the pilot pump 15 and the pilot port of the arm control valve 170A in the control valve unit 17, and is configured to be able to change the flow path area of the pipeline by changing the opening area.

[0049] With this configuration, the controller 30 can operate the hydraulic actuator corresponding to the specific operating device 26 not only when an operation on the specific operating device 26 is being performed, but also when no operation on the specific operating device 26 is being performed. Also, the controller 30 can forcibly stop the operation of the hydraulic actuator corresponding to the specific operating device 26 even when an operation on the specific operating device 26 is being performed.

[0050] For example, as shown in FIG. 3, an arm operation lever 26A, which is an example of the operation device 26, is used to operate the arm 5. Specifically, the arm operation lever 26A utilizes the pilot oil discharged by the pilot pump 15 and applies a pilot pressure corresponding to the operation in the front-rear direction to the pilot port of the arm control valve 170A. More specifically, when the arm operation lever 26A is operated in the arm closing direction (rear direction), a pilot pressure corresponding to the operation amount is applied to the left pilot port of the arm control valve 170A. Also, when the arm operation lever 26A is operated in the arm opening direction (front direction), a pilot pressure corresponding to the operation amount is applied to the right pilot port of the arm control valve 170A.

[0051] An operation mode switching device SW (mode switch) is provided at the tip of the arm operation lever 26A. The operator can operate the arm operation lever 26A while pressing the mode switch. Note that the mode switch may be provided at other positions within the cabin 10.

[0052] An arm operation sensor 29A, which is an example of the operation content detection device 29, detects the content of the front-rear direction operation of the arm operation lever 26A by the operator and outputs the detected value to the controller 30. The content of the operation of the arm operation lever 26A includes the operation direction and the operation amount.

[0053] The arm solenoid valve 50A operates according to a control command (current command) output by the automatic control unit 30C of the controller 30. Then, it adjusts the pilot pressure by the pilot oil introduced from the pilot pump 15 to the pilot port of the arm control valve 170A via the arm solenoid valve 50A. The arm solenoid valve 50A can adjust the pilot pressure so that the arm control valve 170A can be stopped at an arbitrary valve position.

[0054] With this configuration, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the pilot port of the arm control valve 170A via the arm solenoid valve 50A in response to the arm opening / closing operation by the operator. Also, the controller 30 can supply the pilot oil discharged from the pilot pump 15 to the pilot port of the arm control valve 170A via the arm solenoid valve 50A regardless of the arm opening / closing operation by the operator. That is, the controller 30 can open and close the arm 5 in response to the arm opening / closing operation by the operator or regardless of the arm opening / closing operation by the operator.

[0055] Also, with this configuration, even when the arm opening / closing operation by the operator is being performed, the controller 30 can, if necessary, reduce the pilot pressure acting on the pilot port of the arm control valve 170A and forcibly stop the opening / closing operation of the arm 5.

[0056] For example, even when the arm closing operation by the operator is being performed, the controller 30 can, if necessary, control the right arm solenoid valve 50AR to increase the pilot pressure acting on the opening side (right side) pilot port of the arm control valve 170A, which is on the opposite side of the closing side (left side) pilot port of the arm control valve 170A, and forcibly return the arm control valve 170A to the neutral position, thereby forcibly stopping the closing operation of the arm 5. The same applies when forcibly stopping the opening operation of the arm 5 when the arm opening operation by the operator is being performed.

[0057] Next, referring to FIG. 4, the flow of control (hereinafter referred to as "trajectory speed reference control") in which the controller 30 determines the respective target operating speeds of a plurality of work tools based on the target moving speed (vector quantity) of a predetermined part of the attachment AT on the target trajectory and operates each of the plurality of work tools will be described. FIG. 4 is a flowchart showing an example of the flow of the trajectory speed reference control. The controller 30 repeatedly executes this trajectory speed reference control at a predetermined control cycle.

[0058] First, the controller 30 determines whether the operation mode of the excavator 100 is the semi-automatic operation mode (step ST1). In the illustrated example, the operation mode of the excavator 100 becomes the semi-automatic operation mode when the mode switch, which is an operation mode switching device SW provided at the tip of the arm operation lever 26A, is pressed, and becomes the manual operation mode when the mode switch is not pressed.

[0059] If it is determined that the operation mode of the excavator 100 is not the semi-automatic operation mode (NO in step ST1), the controller 30 ends the current trajectory speed control. That is, the controller 30 repeats the determination in step ST1 until it is determined that the operation mode of the excavator 100 is the semi-automatic operation mode.

[0060] If it is determined that the operation mode of the excavator 100 is the semi-automatic operation mode (YES in step ST1), the controller 30 acquires the target trajectory (step ST2). In the illustrated example, the controller 30 generates the target trajectory based on the target construction surface data and the coordinates of a predetermined part of the current attachment AT. Note that the target trajectory may be set in advance.

[0061] FIG. 5 is a diagram showing an example of the target trajectory TL when the excavation work by the excavator 100 is performed. In FIG. 5, the bucket position 61 indicates the position of the bucket 6 before the excavation, the bucket position 62 indicates the position of the bucket 6 when the excavation is being performed, and the bucket position 63 indicates the position of the bucket 6 lifted upward after the excavation. The position of the bucket 6 changes in the order of the bucket position 61, the bucket position 62, and the bucket position 63, and the bucket tip 6a as a predetermined part of the attachment AT moves along the target trajectory TL.

[0062] Thereafter, the controller 30 sets the target moving speed of a predetermined part of the attachment AT (step ST3). In the illustrated example, the automatic control unit 30C of the controller 30 sets the target moving speed based on the operation amount of the arm operation lever 26A and the magnitude of the working load. For example, in the example shown in FIG. 5, the predetermined part of the attachment AT is the tip 6a of the bucket 6, and the target moving speed MV is the tip speed vector. The tip speed vector includes the target moving direction of the tip 6a and the target speed (target moving amount per unit time) of the tip 6a.

[0063] The automatic control unit 30C increases the target speed (target moving amount per unit time) of the tip 6a moving on the target trajectory TL as the operation amount of the arm operation lever 26A in the arm closing direction increases. Further, the automatic control unit 30C decreases the target speed (target moving amount per unit time) of the tip 6a moving on the target trajectory TL as the excavation load as the working load increases. The excavation load is calculated based on, for example, the detection value of the attitude detection device PS and the detection value of the load detection device LS.

[0064] Thereafter, the controller 30 determines the target operating speeds of the respective work tools (step ST4). In the illustrated example, the automatic control unit 30C of the controller 30 determines the target operating speed of the boom 4 and the target operating speed of the arm 5 based on the direction and magnitude of the tip speed vector as the target moving speed MV.

[0065] The target operating speed of the boom 4 is, for example, the target angular velocity of the boom angle or the target extension speed of the boom cylinder 7, etc., and the target operating speed of the arm 5 is, for example, the target angular velocity of the arm angle or the target extension speed of the arm cylinder 8, etc.

[0066] Thereafter, the controller 30 outputs a control command to the drive control device 50 (step ST5). In the illustrated example, the automatic control unit 30C of the controller 30 outputs a current command corresponding to the determined target operating speed of the arm 5 to the arm solenoid valve 50A. Similarly, the automatic control unit 30C outputs a current command corresponding to the determined target operating speed of the boom 4 to a boom solenoid valve (not shown).

[0067] Thus, the controller 30 does not determine the target operating speed of the boom 4 according to the target operating speed of the arm 5, but determines the tip speed vector based on the operation amount of the operating device 26 (arm operation lever 26A) and the magnitude of the load related to the attachment AT. The magnitude of the tip speed vector (the target movement amount per unit time of the tip 6a) is proportional to the operation amount of the operating device 26 (arm operation lever 26A) and inversely proportional to the magnitude of the load related to the attachment AT. Note that the load related to the attachment AT may be the load related to each working tool. That is, the load related to the attachment AT may be, for example, the load related to the raising and lowering of the boom 4 calculated based on the detection value of the boom bottom pressure sensor S7B or the boom rod pressure sensor S7R, or the load related to the opening and closing of the arm 5 calculated based on the detection value of the arm bottom pressure sensor S8B or the arm rod pressure sensor S8R.

[0068] Then, for example, when both the operation amount of the operating device 26 and the magnitude of the load related to the attachment AT are constant, the controller 30 determines the respective target operating speeds of the boom 4 and the arm 5 so that the magnitude of the tip speed vector (the target movement amount per unit time of the tip 6a) along the target trajectory TL becomes constant.

[0069] FIG. 5 shows that the magnitudes of the tip speed vectors MV1 at the bucket position 61, MV2 at the bucket position 62, and MV3 at the bucket position 63 are the same. The tip speed vectors MV1, MV2, and MV3 are examples of the target movement speed MV. Note that the target operating speed of the boom 4 at the bucket position 61 is zero or almost zero, and the target operating speed of the arm 5 at the bucket position 63 is zero or almost zero.

[0070] In the conventional control for determining the target operating speed of the boom 4 according to the target operating speed of the arm 5, the target operating speed of the boom 4 is calculated to be a real multiple of the target operating speed of the arm 5, and there may be a case where the target operating speed of the boom 4 becomes excessive. However, in the orbital speed reference control, the target operating speed of the boom 4 does not become excessive. This is because the magnitude of the tip speed vector (the target movement amount of the tip 6a of the bucket 6 per unit time) is determined to be a value within an appropriate range according to the operation amount of the operating device 26 and the magnitude of the work load, and does not become excessive. Also, since the movement of the tip 6a is realized by the combination of the movement of the boom 4 and the movement of the arm 5, the larger the target operating speed of one of the boom 4 and the arm 5, the smaller the maximum value of the value adopted as the target operating speed of the other.

[0071] Therefore, when the orbital speed reference control is executed, the controller 30 can, for example, reduce the target operating speed of the arm 5 when the target operating speed of the boom 4 increases, so that the boom 4 can be operated without difficulty.

[0072] Note that the movement of a predetermined portion along the target orbit TL may be realized by the operation of the attachment AT and the turning operation of the upper swing body 3. Also, the operation of the attachment AT may include the turning of the bucket 6. In this case, the automatic control unit 30C determines at least one of the target operating speed of the boom 4, the target operating speed of the arm 5, the target operating speed of the bucket 6, and the target turning speed of the upper swing body 3.

[0073] Next, referring to FIG. 6, the data flow in the orbital speed reference control will be described. FIG. 6 is a data flow diagram of the orbital speed reference control. In this example, the tip 6a of the bucket 6 as a predetermined portion of the attachment AT is already located on the preset target orbit TL.

[0074] Based on the arm operation amount detected by the arm operation sensor 29A as the operation content detection device 29 (the operation amount of the arm operation lever 26A) and the magnitude of the working load (excavation load) detected by the load detection device LS, the controller 30 derives the tip speed vector as the target movement speed (vector quantity). The controller 30 may calculate the tip speed vector using the arm operation amount, the magnitude of the working load, and a predetermined calculation formula, or may derive the tip speed vector using a look-up table map that assigns an output value (tip speed vector) to an input value (the arm operation amount and the magnitude of the working load).

[0075] Thereafter, the controller 30 calculates the target operating speed of the working tool using the derived tip speed vector, the attachment angle detected by the attitude detection device PS, the target construction surface data pre-stored in the storage device MD of the controller 30, and inverse kinematics. Specifically, the controller 30 calculates the target operating speed of the boom 4 and the target operating speed of the arm 5. Note that the attachment angle includes the boom angle, the arm angle, and the bucket angle. Also, the controller 30 may calculate the target operating speed of the working tool without using the target construction surface data.

[0076] Thereafter, the controller 30 outputs a current command corresponding to the calculated target operating speed of the arm 5 to the arm solenoid valve 50A, and outputs a current command corresponding to the calculated target operating speed of the boom 4 to the boom solenoid valve 50B.

[0077] Using such trajectory speed reference control, the controller 30 can move the tip 6a of the bucket 6 along the target trajectory TL at the target movement speed MV according to the operation amount of the arm operation lever 26A by the operator. Therefore, it is possible to prevent the operating speed of the arm 5 from becoming excessively large or the operating speed of the boom 4 from becoming excessively large.

[0078] Next, referring to FIG. 7, the remote operation system SYS will be described. FIG. 7 is a schematic diagram showing an example of the remote operation system SYS. As shown in FIG. 7, the remote operation system SYS includes an excavator 100 and a remote operation room RC. The excavator 100 and the remote operation room RC are connected via a wireless communication network such as a short-range wireless communication network, a mobile phone communication network, or a satellite communication network.

[0079] In the illustrated example, the communication device T1 mounted on the excavator 100 is configured to transmit and receive information to and from the communication device T2 installed in the remote operation room RC via wireless communication. In the remote operation room RC, a controller 30, a display device RD, an operation device 26, an operation content detection device 29, a communication device T2, etc. are installed. Further, in the remote operation room RC, a driver's seat DE on which an operator OP who remotely operates the excavator 100 sits is installed. And an operation mode switching device SW is provided at the tip of the operation device 26.

[0080] The controller 30 generates an operation signal based on the output of the operation content detection device 29. Then, the controller 30 transmits the generated operation signal toward the excavator 100 via wireless communication. Also, the controller 30 receives the outputs of a camera, a load detection device LS, an attitude detection device PS, a positioning device S6, etc. mounted on the excavator 100 via wireless communication.

[0081] The display device RD is configured to display information regarding the situation around the excavator 100. In the illustrated example, the display device RD is a multi-display composed of nine monitors arranged in three rows and three columns vertically, and is configured to be able to display the states of the spaces in front of, to the left of, and to the right of the excavator 100 based on the images captured by the cameras attached to the excavator 100.

[0082] With this remote operation system SYS, the operator OP can utilize trajectory speed control in the same way as an operator inside the cab 10. For example, the tip 6a of the bucket 6 can be moved along the target trajectory TL at a target movement speed MV corresponding to the operation amount of the arm operation lever 26A. Therefore, it is possible to prevent the operating speed of the arm 5 from becoming excessively large or the operating speed of the boom 4 from becoming excessively large.

[0083] As described above, the excavator 100 according to the embodiment of the present disclosure includes a lower traveling body 1, an upper swing body 3 swingably mounted on the lower traveling body 1, an attachment AT including a boom 4 and an arm 5 attached to the upper swing body 3, and a controller 30 as a control device that operates the boom 4 and the arm 5 so as to move a predetermined part of the attachment AT along the target trajectory TL. The controller 30 is configured to determine the respective target operating speeds of the boom 4 and the arm 5 based on the target movement speed MV of a predetermined part of the attachment AT on the target trajectory TL. Note that the predetermined part of the attachment AT is, for example, the tip 6a of the bucket 6 or the back surface of the bucket 6. Further, the target movement speed MV is a vector quantity having magnitude and direction. Also, the excavator 100 is typically a manned excavator equipped with a cab 10, but may be an unmanned (fully automatic) excavator that does not require an operator, or a remotely operated excavator.

[0084] With this configuration, the excavator 100 can achieve smooth movement of the attachment AT in the semi-automatic operation mode. This is because, rather than determining the operating speed of one specific working implement based on the operating speed of another working implement, the operating speed of each of one or more working implements is determined based on the moving speed of a predetermined part. That is, this is to prevent the operating speed of another working implement from becoming excessively large as the operating speed of one specific working implement increases. Specifically, in a configuration where the operating speed of one specific working implement is used to determine the operating speed of another working implement, the operating speed of another working implement (calculated as a real number multiple of the operating speed of that one specific working implement) may become excessively large as the operating speed of that one specific working implement increases. In contrast, in the configuration of the present disclosure, this is because the operating speed of another working implement is not calculated as a real number multiple of the operating speed of that one specific working implement. Note that the working implements are the boom 4, the arm 5, the bucket 6, or the like.

[0085] Further, the excavator 100 may include an operation content detection device 29 that detects the operation content of the operation device 26 for operating the attachment AT. In this case, the controller 30 may be configured to determine the target moving speed MV of a predetermined part of the attachment AT on the target trajectory TL based on the operation content of the operation device 26 detected by the operation content detection device 29. Further, the movement of a predetermined part of the attachment AT along the target trajectory TL is typically realized by the operation of at least one of the boom 4, the arm 5, and the bucket 6, but may also be realized by the slewing operation of the upper slewing body 3 or the traveling operation of the lower traveling body 1.

[0086] With this configuration, the controller 30 can increase or decrease the magnitude of the target moving speed MV by increasing or decreasing the operation amount of the operation device 26, so that an intuitive operation feeling can be given to the operator.

[0087] Further, the excavator 100 may be provided with a load detection device LS for detecting the magnitude of the working load. In this case, the controller 30 may be configured to determine the target moving speed MV of a predetermined part of the attachment AT on the target trajectory TL based on the operation content of the operating device 26 detected by the operation content detection device 29 and the magnitude of the working load detected by the load detection device LS.

[0088] With this configuration, the controller 30 can suppress the occurrence of an overly slow operation of the working tool or an overly sensitive operation of the working tool by determining the magnitude of the target moving speed MV of the predetermined part regardless of the magnitude of the working load.

[0089] Further, the controller 30 may be configured to decrease the target moving speed MV of a predetermined part of the attachment AT on the target trajectory TL as the working load detected by the load detection device LS increases.

[0090] With this configuration, the controller 30 can suppress the occurrence of wasteful energy consumption or damage to the working tool by preventing the magnitude of the target moving speed MV of the predetermined part from being excessively increased despite the large working load.

[0091] Further, when the power consumption for moving the attachment AT is smaller than the output power that the drive source 11 can output, the controller 30 increases the target movement speed MV of a predetermined part of the attachment AT on the target trajectory TL as the operation amount of the operation device 26 increases. When the power consumption for moving the attachment AT is larger than the output power that the drive source 11 can output, the controller 30 may be configured not to increase the target movement speed MV of a predetermined part of the attachment AT on the target trajectory TL even if the operation amount of the operation device 26 increases. For example, when the boom 4 and the arm 5 are operated simultaneously, the controller 30 determines the respective target operation speeds of the boom 4 and the arm 5 so that the power consumption of the main pump 14 for operating the boom 4 and the arm 5 does not exceed the output power of the diesel engine as the drive source 11. Note that the power consumption of the main pump 14 is derived, for example, by multiplying the discharge amount and the discharge pressure of the main pump 14. Also, the output power may be a preset value smaller than the output power that the drive source 11 can output.

[0092] With this configuration, when the controller 30 executes the trajectory speed reference control, it is possible to suppress the absorption power by the main pump 14 from exceeding the output power of the drive source 11 and the movement of the attachment AT from becoming awkward. Also, the controller 30 can suppress the occurrence of a stall of the diesel engine as the drive source 11.

[0093] Further, the excavator 100 may include an operation mode switching device SW for switching the operation mode between a manual operation mode and a semi-automatic operation mode. Then, for example, when the manual operation mode is adopted, the controller 30 only operates the arm 5 when the arm operation lever 26A is operated, but when the semi-automatic operation mode is adopted, when the arm operation lever 26A is operated, at least one of the boom 4, the arm 5, and the bucket 6 is operated, and the tip 6a of the bucket 6 can be moved along the target trajectory TL.

[0094] With this configuration, the operator of the excavator 100 can selectively use the manual operation mode and the semi-automatic operation mode as needed.

[0095] As described above, the preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments. Various modifications, substitutions, etc. can be applied to the above-described embodiments without departing from the scope of the present invention. Also, the features described separately can be combined as long as no technical contradiction occurs.

Explanation of Reference Numerals

[0096] 1 ··· Lower traveling body 1L ··· Hydraulic motor for left traveling 1R ··· Hydraulic motor for right traveling 2 ··· Slewing mechanism 2A ··· Hydraulic motor for slewing 3 ··· Upper slewing body 4 ··· Boom 5 ··· Arm 6 ··· Bucket 7 ··· Boom cylinder 8 ··· Arm cylinder 9 ··· Bucket cylinder 10 ··· Cabin 11 ··· Drive source 14 ··· Main pump 15 ··· Pilot pump 17 ··· Control valve unit 25 ··· Pilot line 26 ··· Operating device 26A ··· Arm operation lever 29 ··· Operating content detection device 29A ··· Arm operation sensor 30 ··· Controller 30A ··· Position calculation section 30B ··· Trajectory generation section 30C ··· Automatic control section 50 ··· Drive control device 50A ··· Solenoid valve for arm 50AL ··· Solenoid valve for left arm 50AR ··· Solenoid valve for right arm 50B ··· Solenoid valve for boom 61, 62, 63 ··· Bucket position 100 ··· Excavator 170 ··· Control valve 170A ··· Control valve for arm AT ··· Attachment DE ··· Driver's seat LS ··· Load detection device MD ··· Memory device MV ··· Target moving speed MV1, MV2, MV3 ··· Tip speed vector OP ··· Operator PS ··· Posture detection device RC ··· Remote operation room RD ··· Display device S1 ··· Boom angle sensor S2 ··· Arm angle sensor S3 ··· Bucket angle sensor S4 ··· Machine body tilt sensor S5 ··· Slewing angular velocity sensor S6 ··· Positioning device S7B ··· Boom bottom pressure sensor S7R ··· Boom rod pressure sensor S8B ··· Arm bottom pressure sensor S8R ··· Arm rod pressure sensor S9B ··· Bucket bottom pressure sensor S9R ··· Bucket rod pressure sensor S10F ··· First left traveling pressure sensor S10S ··· Second left traveling pressure sensor S11F ··· First right traveling pressure sensor S11S ··· Second right traveling pressure sensor S12F ··· First slewing pressure sensor S12S ··· Second slewing pressure sensor S13 ··· Discharge pressure sensor SW ··· Operation mode switching device SYS ··· Remote operation system T1, T2 ··· Communication device

Claims

1. A lower traveling body, an upper slewing body rotatably mounted on the lower traveling body, an attachment including a boom and an arm attached to the upper slewing body, and a control device configured to operate the boom and the arm so as to move a predetermined portion of the attachment along a target trajectory. The control device determines respective target operating speeds of the boom and the arm based on a target moving speed of the predetermined portion of the attachment on the target trajectory. A hydraulic excavator characterized by the above.

2. An operation content detection device for detecting an operation content of an operation device for operating the attachment is provided. The control device determines a target moving speed of the predetermined portion of the attachment on the target trajectory based on the operation content of the operation device detected by the operation content detection device. The hydraulic excavator according to Claim 1.

3. A load detection device for detecting the magnitude of a working load is provided. The control device determines a target moving speed of the predetermined portion of the attachment on the target trajectory based on the operation content of the operation device detected by the operation content detection device and the magnitude of the working load detected by the load detection device. The hydraulic excavator according to Claim 2.

4. The control device decreases the target moving speed of the predetermined portion of the attachment on the target trajectory as the working load detected by the load detection device increases. The hydraulic excavator according to Claim 3.

5. The control device when the consumption power consumed when moving the attachment is smaller than the output power that the drive source can output, increases the target moving speed of the predetermined portion of the attachment on the target trajectory as the operation amount of the operation device increases; when the consumption power consumed when moving the attachment becomes larger than the output power that the drive source can output, does not increase the target moving speed of the predetermined portion of the attachment on the target trajectory even if the operation amount of the operation device increases. The hydraulic excavator according to any one of Claims 2 to 4.

Images