Work machine

Abstract

The present application aims to provide a work machine capable of improving workability by maintaining a work state of a work tool in line with an operator's intention in machine control to follow a work target surface. Therefore, a controller determines a work state of a work tool based on an operation input amount input from an operation input device and a posture of the work tool with respect to a target surface, and calculates a range of an actuator command value of an actuator that maintains the determined work state, and corrects the actuator command value within the range so that the distance between the work tool and the target surface is reduced.

Description

Technical Field

[0001] This invention relates to construction machinery used in road construction, building construction, civil engineering, dredging, and dismantling projects. Background Technology

[0002] As a type of construction machinery used in road construction, building construction, civil engineering, dredging, etc., it is known to have a structure in which a multi-jointed working front section is mounted on the main body of the construction machinery and driven by a power cylinder. The main body of the construction machinery has a rotating body mounted rotatably on top of a traveling body that travels via a power system. As an example, there exists a hydraulic excavator with a working front section consisting of a boom, stick, bucket, etc.

[0003] In some hydraulic excavators, the machine tool can perform so-called machine tool control, which pre-sets the construction target surface to be excavated and automatically controls the boom movement in accordance with the operator's stick movements, so that the bucket can excavate along the construction target surface.

[0004] However, in this type of hydraulic excavator, excavators with automatic control of the bucket's movement are widely known. However, when the bucket angle is automatically controlled without the operator's intended operation, the operability of the hydraulic excavator is reduced because the operator cannot perform the desired bucket operation.

[0005] For example, Patent Document 1 discloses a technology related to a control device and control method for construction machinery: by controlling the bucket to maintain a constant angle based on the operator's operating state of the bucket and the distance between the bucket and the construction target surface, the bucket control is performed in accordance with the operator's intention.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2017 / 086488 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] In excavators operated by machine tool control, it is important to ensure that the bucket accurately tracks the target surface. However, by controlling the bucket's movement based on the boom and stick movements to reduce the distance between the bucket and the target surface, it is possible to achieve even more precise bucket tracking.

[0011] However, controlling the bucket's movement by keeping the bucket's claw tip always close to the target surface may deviate from the operator's desired bucket operating state. For example, during excavation on the claw tip side, if the rear end of the bucket's bottom surface (opposite to the claw tip) is below the target surface compared to the claw tip side, the bucket's bottom surface will be in contact with the ground, making continuous excavation impossible on the claw tip side. Conversely, when performing friction operations on the rear end of the bucket's bottom surface, if the claw tip is below the target surface compared to the rear end of the bucket, ground excavation on the claw tip side will prevent friction operations from being performed.

[0012] The present invention was made in view of the above-mentioned problems, and its object is to provide a machine tool that can improve workability by maintaining the working state of the working tool in accordance with the operator's intention in the machine tool control that enables the working tool to follow the construction target surface.

[0013] Methods for solving problems

[0014] To achieve the above objectives, the present invention provides a working machine comprising: a main body; a working front part having a working tool, which is flexibly mounted on the main body in a vertical direction; an actuator that drives the working front part; a drive device that drives the actuator; an operation input device that instructs the action of the actuator; a posture detection device that detects the posture of the main body and the working front part; a target surface information setting device that sets a target surface as the excavation object of the working tool; and a controller that calculates the action command value of the actuator based on information input from the operation input device, the posture detection device, and the target surface information setting device, and outputs it to the drive device, causing the working tool to move along the target surface. The controller determines the working state of the working tool based on the operation input quantity input from the operation input device and the posture of the working tool relative to the target surface, and calculates the range of the action command value of the actuator that maintains the determined working state, and corrects the action command value of the actuator within the range, thereby reducing the distance between the working tool and the target surface.

[0015] According to the present invention configured as described above, in machine tool control that enables the working tool to follow the target surface of the construction, the operability of the working machine can be improved by maintaining the working state of the working tool in accordance with the operator's intention.

[0016] Invention Effects

[0017] According to the present invention, in machine tool control that enables the working tool to follow the target surface of the construction, the operability of the working machine can be improved by maintaining the working state of the working tool in accordance with the operator's intention. Attached Figure Description

[0018] Figure 1 This is a side view of a hydraulic excavator according to an embodiment of the present invention.

[0019] Figure 2 It is shown Figure 1 The diagram shows the configuration of the control system of a hydraulic excavator.

[0020] Figure 3 yes Figure 2 The diagram shows the functional block diagram of the information processing device.

[0021] Figure 4 This is a diagram showing the actions of the front part of the machine tool control operation.

[0022] Figure 5 It is a diagram showing the bucket movement trajectory that is to be achieved through machine tool control.

[0023] Figure 6 It is a diagram showing the actual bucket movement trajectory controlled by the machine tool.

[0024] Figure 7 It is a diagram showing the target movement trajectory of the bucket during excavation operations.

[0025] Figure 8 It is a diagram showing the target motion trajectory of the bucket during friction operation.

[0026] Figure 9 This is a side view of a slope bucket.

[0027] Figure 10A This is a diagram illustrating the trajectory of a bucket movement controlled by a machine tool in the prior art.

[0028] Figure 10B This is a diagram illustrating the bucket movement trajectory controlled by a machine tool according to an embodiment of the present invention.

[0029] Figure 11 This is a flowchart illustrating the processing content of the information processing apparatus according to an embodiment of the present invention. Detailed Implementation

[0030] Hereinafter, a hydraulic excavator will be used as an example of the working machinery in the embodiments of the present invention, and will be described with reference to the accompanying drawings. It should be noted that in each drawing, equivalent parts are labeled with the same reference numerals and repeated descriptions are omitted where appropriate.

[0031] <Hydraulic Excavator>

[0032] Figure 1 This is a side view of the hydraulic excavator in this embodiment. (As shown) Figure 1 As shown, the hydraulic excavator 1 includes a front working part 2, a rotating body 3 that constitutes the main body of the machine, and a traveling body 4.

[0033] The working front part 2 rotates relative to the rotating body 3 about the connecting part, and the rotating body 3 rotates relative to the traveling body 4 about the connecting part. The working front part 2 includes: a boom 20, one end of which is connected to the rotating body 3; a stick 21, one end of which is connected to the boom 20; a bucket 22, one end of which is connected to the stick 21; a boom cylinder 20A, both ends of which are connected to the boom 20 and the rotating body 3 respectively; a stick cylinder 21A, both ends of which are connected to the stick 21 and the boom 20 respectively; a first connecting rod 22B, one end of which is connected to the stick 21; a second connecting rod 22C, one end of which is connected to the bucket 22; and a bucket cylinder 22A, one end of which is connected to the other end of the first connecting rod 22B and the second connecting rod 22C, and the other end of which is connected to the stick 21. These components are configured to rotate vertically about the connecting part. The running gear 4 is equipped with a running motor 41 and tracks 45.

[0034] The boom cylinder 20A, stick cylinder 21A, and bucket cylinder 22A are designed to extend and retract under hydraulic pressure, enabling the boom 20, stick 21, and bucket 22 to rotate respectively through extension and retraction. The bucket 22 can be arbitrarily replaced with auxiliary devices not shown, such as grab buckets, crushers, rippers, and magnets.

[0035] The boom 20 is equipped with a boom IMU (Inertial Measurement Unit) 20S for detecting the attitude of the boom 20. The stick 21 is equipped with a stick IMU 21S for detecting the attitude of the stick 21. The first link 22B is equipped with a bucket IMU 22S for detecting the attitude of the bucket 22. The boom IMU 20S, stick IMU 21S, and bucket IMU 22S are respectively composed of angular velocity sensors and acceleration sensors.

[0036] The rotating body 3 includes a rotating body IMU 30S, a main frame 31, a driver's cab 32, an information processing unit 34, a drive unit 35, a prime mover 36, a counterweight 37, and a rotation motor 38. The rotating body IMU 30S, driver's cab 32, information processing unit 34, drive unit 35, prime mover 36, counterweight 37, and rotation motor 38 are mounted on the main frame 31. The rotating body IMU 30S is equipped with an acceleration sensor and an angular velocity sensor, capable of detecting the tilt angle of the rotating body 3.

[0037] The driver's cab 32 is equipped with an operation input device 33, a target surface information setting device 100, and a display setting device 110. The operation input device 33 consists of an operating lever 33a and an operation input sensor 33b that detects the operator's operation on the operating lever 33a (both are as follows). Figure 2(As shown). The operation input sensor 33b can convert the target movements of each movable part requested by the operator into electrical signals by detecting the operation amount of the operating lever 33a. It should be noted that the operation input device 33 can also be hydraulically piloted or remotely operated. The target surface information setting device 100 can set the construction target surface as the target of excavation by the front part 2.

[0038] The display setting device 110 consists of a display monitor and a touch panel, which can display the posture of the hydraulic excavator 1, information about the target surface, the positional relationship between the target surface and the front part 2, the distance, etc., or set various dimensions and masses of the front part 2. In addition, it can set a working mode related to the angle of the bucket 22.

[0039] See below Figure 3 Explanation of information processing device 34.

[0040] The drive unit 35 consists of a hydraulic pump 35a, a directional switching valve 35b, and a solenoid control valve 35c. The hydraulic pump 35a generates the hydraulic pressure required for the operation of the hydraulic excavator 1. The solenoid control valve 35c drives the directional switching valve 35b according to the action command value input from the information processing unit 34. The directional switching valve 35b controls the flow rate and direction of the hydraulic oil supplied from the hydraulic pump 35a to the boom cylinder 20A, stick cylinder 21A, bucket cylinder 22A, swivel motor 38, and travel motor 41, which serve as actuators.

[0041] The prime mover 36 is the power source for the hydraulic pump 35a and is composed of an engine 36a.

[0042] The traveling body 4 includes a track frame 40, a travel motor 41, and tracks 45. The tracks 45 are configured to wrap around the track frame 40 via the travel motor 41. The operator can adjust the travel speed of the hydraulic excavator 1 by changing the rotation speed of the travel motor 41 through the operation input device 33. The traveling body 4 is not limited to having tracks 45; it may also have wheels or legs.

[0043] <The Composition of Control Systems>

[0044] Figure 2 The configuration of the control system of the hydraulic excavator 1 is shown. Figure 2 In the system, the control system 10 consists of an operation input device 33, an attitude detection device 30, a target surface information setting device 100, a display setting device 110, an information processing device 34, a drive device 35, and a prime mover 36.

[0045] The operation input device 33 consists of an operating lever 33a and an operation input quantity sensor 33b. The operation quantity of the operating lever 33a is converted into an electrical signal by the operation input quantity sensor 33b and input to the information processing device 34.

[0046] The attitude detection device 30 is equipped with an angular velocity sensor 30a and an acceleration sensor 30b, which can measure the angles of each component of the front part 2 and the rotating body 3.

[0047] The target surface information setting device 100 includes a target surface information setting controller 100a, which can set and manage the construction target surface.

[0048] The display setting device 110 includes a display monitor 110a and a touch panel 110b, which can display to the operator the posture of the hydraulic excavator 1, the area information of the construction target surface set by the target surface information setting device 100, the distance between the front of the workpiece 2 and the construction target surface, etc. In order to implement precise machine tool control, the display setting device 110 can also set the dimensions of the boom 20, stick 21 and bucket 22. In addition, regarding the angle control of the bucket 22, the display setting device 110 can select a mode that automatically maintains the angle of the bucket 22 relative to the construction target surface, a mode that automatically maintains the angle of the bucket 22 relative to the plane of rotation of the rotating body 3 in response to the movement of the stick 21 and the boom 20, and a mode that maintains the angle of the bucket 22 relative to the stick 21, etc.

[0049] The information processing unit 34 includes an information processing controller 34a, which processes control signals and detection signals from various devices. The operation input device 33, attitude detection device 30, target surface information setting device 100, and display setting device 110 are connected to the information processing unit 34. Furthermore, the information processing unit 34 outputs commands to the drive unit 35 for driving the hydraulic excavator 1.

[0050] The drive unit 35 consists of a hydraulic pump 35a, a directional switching valve 35b, and a solenoid control valve 35c. The hydraulic pump 35a generates the hydraulic oil required to drive the hydraulic cylinders 20A, 21A, and 22A, and the hydraulic motors 38 and 41. The directional switching valve 35b drives the hydraulic cylinders 20A, 21A, and 22A, and the hydraulic motors 38 and 41 by adjusting the flow rate and direction of the hydraulic oil supplied from the hydraulic pump 35a. The drive unit 35 can also drive auxiliary devices and equipment not included above.

[0051] The prime mover 36 is composed of an engine 36a. The engine 36a drives the hydraulic pump 35a. The prime mover 36 is not limited to this configuration and may also use other power sources such as an electric motor.

[0052] <Operation Input Device>

[0053] The hydraulic excavator 1 is typically configured such that increasing the amount of operation of the control lever 33a increases the speed of the actuators. The operator can adjust the speed of operation of each actuator 20A, 21A, 22A, 38, and 41 by adjusting the amount of operation of the control lever 33a.

[0054] The operation input device 33 includes an operation input sensor 33b that electrically detects the operation amount (operation input amount) of the operating lever 33a, and can send the target action of the actuator requested by the operator to the information processing device 34. The operation input sensor 33b is not limited to directly detecting the operation amount of the operating lever 33a, but can also detect the operation pilot pressure.

[0055] <Attitude Detection Device>

[0056] The attitude detection device 30 is equipped with angular velocity sensors and acceleration sensors on the rotating body IMU 30S, boom IMU 20S, stick IMU 21S, and bucket IMU 22S, respectively. Angular velocity and acceleration information at each position can be obtained through these IMUs. The boom 20, stick 21, bucket 22, boom cylinder 20A, stick cylinder 21A, bucket cylinder 22A, first link 22B, second link 22C, and rotating body 3 are all mounted in a swingable manner, thus allowing the attitude of the boom 20, stick 21, bucket 22, and rotating body 3 to be estimated based on the mechanical linkage relationships. It should be noted that the attitude detection method shown here is an example; the relative angles of the various parts of the front working section 2 can also be directly measured, or the strokes of the boom cylinder 20A, stick cylinder 21A, and bucket cylinder 22A can be measured to calculate the attitude of each part of the hydraulic excavator 1.

[0057] <Target Surface Information Setting Device>

[0058] The target surface information setting device 100 can set the construction target surface as the excavation target of the work front 2. The construction target surface can be set not only as a single plane, but also as having multiple planes or defining the excavation range that the work front 2 can cover. The construction target surface can be set in a coordinate system based on the working machinery 1 or in a coordinate system based on the Earth. The method for setting the construction target surface can also read model data such as 3D data.

[0059] <Driver>

[0060] The drive unit 35 consists of a hydraulic pump 35a, a directional switching valve 35b, and a solenoid control valve 35c. Based on the action command value input from the information processing unit 34, it controls the flow rate of working oil (hydraulic oil) supplied to the actuators (hydraulic cylinders 20A, 21A, 22A and hydraulic motors 38, 41) driving the hydraulic excavator 1. The action command value input from the information processing unit 34 is converted into pilot pressure by the solenoid control valve 35c, and this pilot pressure drives the directional switching valve 35b. The directional switching valve 35b controls the operating speed of the actuators 20A, 21A, 22A, 38, 41 by adjusting the flow rate of the working oil supplied to them.

[0061] <Information Processing Device>

[0062] Figure 3 This is a functional block diagram of the information processing device 34. For example... Figure 3 As shown, the information processing device 34 is connected to the attitude detection device 30, the operation input device 33, the target surface information setting device 100, the display setting device 110, and the drive device 35. The information processing device 34 consists of an attitude calculation unit 210, a target surface distance calculation unit 220, a target speed calculation unit 310, a bucket angle control determination unit 410, a bucket travel direction determination unit 420, a bucket operating status determination unit 430, a bucket correction limit value calculation unit 440, a bucket target speed correction unit 450, and an action command value calculation unit 610.

[0063] The attitude calculation unit 210 calculates the attitude of the front part 2 and the rotating body 3 based on the signals detected by the attitude detection device 30. The calculation results of the attitude calculation unit 210 are output to the target surface distance calculation unit 220, the bucket angle control determination unit 410 and the target speed calculation unit 310.

[0064] The target surface distance calculation unit 220 calculates the distance between any number of points set on the bucket 22 and the construction target surface based on the calculation results of the target surface information setting device 100 and the attitude calculation unit 210. The calculation results of the target surface distance calculation unit 220 are output to the display setting device 110, the bucket angle control determination unit 410, the target speed calculation unit 310, the bucket travel direction determination unit 420, the bucket operation status determination unit 430, the bucket correction limit value calculation unit 440, and the bucket target speed correction unit 450.

[0065] Regarding the angle control of the bucket 22 set in the display setting device 110, the bucket angle control determination unit 410 determines the control state related to the angle control of the bucket 22 based on the operation input amount from the operation input device 33 and the calculation results of the attitude calculation unit 210 and the target surface distance calculation unit 220, and outputs the results to the target speed calculation unit 310, the bucket operation state determination unit 430 and the bucket target speed correction unit 450.

[0066] The target speed calculation unit 310 calculates the target speed of the actuators 20A, 21A, and 22A driving the front work unit 2 based on the operation input device 33's operation quantity information, the distance between the bucket 22 and the construction target surface calculated by the target surface distance calculation unit 220, the calculation results of the bucket angle control determination unit 410, and the calculation results of the attitude calculation unit 210. The calculation results of the target speed calculation unit 310 are output to the bucket travel direction determination unit 420, the bucket target speed correction unit 450, and the action command value calculation unit 610.

[0067] The bucket travel direction determination unit 420 determines the direction of travel of the bucket 22, i.e., whether it travels towards the claw tip side or towards the opposite side (rear end side), based on the calculation results of the target surface distance calculation unit 220 and the target speed calculation unit 310, and outputs the result to the bucket operation status determination unit 430.

[0068] The bucket operation status determination unit 430 determines the operation status of the bucket 22 based on the calculation results of the target surface distance calculation unit 220, the bucket angle control determination unit 410, and the bucket travel direction determination unit 420. That is, it determines which of the following is the state of digging on the claw tip side of the bucket 22 (digging state), the state of friction on the side of the bucket 22 opposite to the claw tip (friction state), and the state of friction on the claw tip side of the bucket 22 (friction state), and outputs the result to the bucket correction limit value calculation unit 440.

[0069] The bucket correction limit calculation unit 440 calculates the upper limit value (bucket correction limit value) of the angle correction amount to maintain the working state of the bucket 22 based on the calculation results of the target surface distance calculation unit 220 and the bucket working state determination unit 430. In addition, the bucket correction limit calculation unit 440 calculates the upper limit value (bucket correction limit value) of the angular velocity correction amount of the bucket 22 that does not cause discomfort to the operator. The calculation result (bucket correction limit value) of the bucket correction limit calculation unit 440 is output to the bucket target speed correction unit 450.

[0070] The bucket target speed correction unit 450 corrects the target speed of the bucket 22 based on the calculation results of the bucket angle control determination unit 410, the target surface distance calculation unit 220, the bucket correction limit value calculation unit 440, and the target speed calculation unit 310.

[0071] The action command value calculation unit 610 calculates the action command value required to control the drive device 35 based on the calculation results of the target speed calculation unit 310 and the bucket target speed correction unit 450, and outputs it to the drive device 35.

[0072] <Machine Tool Control Actions>

[0073] Figure 4 The image shows the operation of the machine tool control front unit 2. For example... Figure 4 As shown, in machine tool control, the boom 20 is automatically controlled according to the movement speed of the stick 21, so that the bucket 22 moves along the set target surface. For example, when the operator is... Figure 4 When the boom 21 is retracted in the indicated state, the boom 20 automatically rises or falls, causing the claw tip of the bucket 22 to move along the target surface. Thus, the operator can perform excavation work along the target surface without requiring skilled operation.

[0074] Figure 5 The image shows the desired motion trajectory (target motion trajectory) of the bucket 22 to be achieved through machine tool control. For example... Figure 5 As shown, the angle control of the bucket 22 can be automatically performed in the machine tool control. The angle control of the bucket 22 includes controlling the movement of the bucket 22 in a manner that keeps its angle constant relative to the target construction surface; controlling the movement of the bucket 22 in a manner that keeps its angle constant relative to the plane of rotation of the rotating body 3 in accordance with the movements of the boom 20 and stick 21; and controlling the movement of the bucket 22 in a manner that keeps its angle relative to the stick 21 constant. The above-mentioned angle control of the bucket 22 can automatically switch according to the operator's selected operation, or based on the operator's operation amount of the bucket 22, the distance between the bucket 22 and the target construction surface, and the attitude of the bucket 22 relative to the target construction surface. For example, in this embodiment, the movement of the bucket 22 is normally controlled in advance to keep the angle of the bucket 22 relative to the stick 21 constant. The operator sets the mode to keep the angle of the bucket 22 constant by means of the display setting device 110. When the movement speed of the bucket 22 requested by the operator is less than the movement speed of the bucket 22 requested by the machine tool control, the distance between the bucket 22 and the construction target surface is less than a specified value, and when the bottom surface of the bucket 22 is parallel to the construction target surface, the movement of the bucket 22 is controlled in a way that keeps the angle of the bucket 22 constant relative to the rotation plane of the rotating body 3.

[0075] <Bucket Movement Trajectory>

[0076] Figure 6The actual movement trajectory of the bucket 22 controlled by the machine tool is shown. Typically, in a hydraulic excavator 1, from a strength perspective, the working front section 2 is heavy and has a large mass and inertia due to its thick construction. Furthermore, in the case of a hydraulic system, since the working oil driving the working front section 2 is a compressible fluid, it is difficult to precisely control the movement of the working front section 2. Therefore, in practice, when it is desired to control the movement of the stick 21 and boom 20 to make the bucket 22 follow the target surface, such as... Figure 6 As shown, the bucket 22 will deviate from the target surface. This results in unevenness on the excavated ground. It should be noted that... Figure 6 The motion trajectory shown in the image is for illustration purposes and is different from the actual scale.

[0077] <Bucket operating status>

[0078] Figure 7 The target motion trajectory of bucket 22 during excavation is shown. Figure 8 The target motion trajectory of the bucket 22 during friction operation is shown. For example... Figure 7 and Figure 8 As shown, in the case where the bucket 22 is a widely used excavating bucket, a claw called a tooth is installed on the front side of the bucket 22, which facilitates ground excavation. An iron plate is installed on the lower part of the bucket 22 for use in compacting the ground or smoothing the ground by rubbing the bottom and rear end of the bucket 22 against the ground. The bucket 22 has various operating states when operated under machine tool control. Figure 7 The image shows the digging state (digging state) on the claw tip side of the bucket 22. Figure 8 The image shows the friction state (friction state) on the rear end side of the bucket 22 opposite to the claw tip. The operation (digging operation or friction operation) of the machine tool-controlled bucket 22 is carried out through a series of actions of the working front part 2, so it is necessary to maintain the working state of the bucket 22 during this period.

[0079] The operating state of the bucket 22 can be determined based on its attitude and direction of travel relative to the target surface. In this embodiment, the distances between the tip of the bucket 22 and the target surface, and between the rear end of the bucket 22 (opposite to the tip) and the target surface are calculated. Based on the magnitude of these distances and the direction of travel of the bucket 22, it is determined whether it is in a digging or friction state. The direction of travel of the bucket 22 can be calculated by extracting the direction component parallel to the target surface from the target velocities of the boom 21 and arm 20. Figure 7 and Figure 8 In the configuration of the front working part 2 shown, the bucket 22 moves towards the claw tip side by pulling back the stick, and moves towards the rear end side opposite to the claw tip by pushing out the stick.

[0080] The following is an example of the conditions used to determine whether a condition is in a digging state or a friction state.

[0081] (i) Conditions used to determine the state of excavation

[0082] When the bucket 22 moves toward the claw tip side with the target surface as the reference and the claw tip side of the bucket 22 is located below the rear end side, the bucket 22 moves toward the claw tip side.

[0083] (ii) Conditions used to determine a frictional state

[0084] When the bucket 22 moves toward the claw tip side with its rear end side below the claw tip side relative to the construction target surface, or when the bucket 22 moves toward the rear end side with its rear end side below the claw tip side relative to the construction target surface, this indicates that the bucket 22 is moving towards the rear end side.

[0085] It should be noted that the conditions used to determine the operating state of the bucket 22 are not limited to those described above. For example, the angle between the bottom surface of the bucket 22 and the target surface can also be used to determine whether it is in an excavation or friction state. Additionally, the bucket 22 may be a sloping bucket with an edge on the rear end side (e.g.,...). Figure 9 In the case shown, ground excavation is sometimes carried out on the rear end side of the bucket 22. Therefore, the state in which the bucket 22 moves toward the rear end side with its position lower than the claw tip side can also be judged as the excavation state.

[0086] <Methods for Correcting Bucket Target Speed>

[0087] This describes a correction method used during machine tool control operations to reduce the distance between the bucket 22 and the target surface by adjusting the target speed of the bucket 22. The correction of the target speed of the bucket 22 is based on the operating state of the bucket 22 and the distance between the bucket 22 and the target surface. In this embodiment, when the bucket 22 is moving towards the claw tip side with its claw tip side lower than its rear end side, the displacement of the bucket cylinder 22A is calculated such that the distance between the claw tip of the bucket 22 and the target surface becomes zero. This displacement is then divided by a predetermined time and added to the target speed of the bucket cylinder 22A calculated by the target speed calculation unit 310. The predetermined time is the time required for the distance between the bucket 22 and the claw tip of the target surface to become zero, and is determined to be an appropriate value through experiments, taking into account the characteristics of the hydraulic excavator 1.

[0088] When the bucket 22 moves towards the claw tip with its rear end lower than its claw tip, the displacement of the bucket cylinder 22A is calculated such that the distance between the rear end of the bucket 22 and the target surface becomes zero. This displacement is then divided by the predetermined time and added to the target speed of the bucket cylinder 22A calculated by the target speed calculation unit 310. (This process is repeated three times in the original text.)

[0089] Based on the above method, the distance between the bucket 22 and the target surface can be reduced and the bucket 22 can be made to follow the target surface more closely by moving the bucket 22. However, since ground excavation or friction compaction is carried out in actual machine tool control operations, therefore... Figure 6 As shown, the excavated ground surface is uneven as the claw tip of the bucket 22 moves away from or extends below the target surface. Therefore, in existing machine tool controls, such as... Figure 10A As shown, when the claw tip of the bucket 22 is below the target surface, the action command value of the bucket 22 is corrected by pointing the claw tip of the bucket 22 upwards, thereby preventing the ground from being dug deeper. However, as a result, despite the operator performing the desired digging operation, the digging state of the bucket 22 is disengaged against the operator's intention, creating an area where digging operations cannot be performed.

[0090] <Methods for Limiting Bucket Target Speed ​​Correction>

[0091] In order to Figure 10A To maintain the digging state of the bucket 22 in the "area where digging operations cannot be performed" shown, it is necessary to use the target construction surface as a reference, ensuring that the rear end of the bucket 22 is above the claw tip. Therefore, as Figure 10B As shown, the action command value of the bucket cylinder 22A is modified to prevent the claw tip of the bucket 22 from being positioned above the rear end relative to the target surface. Therefore, by preventing the rear end of the bucket 22 from being positioned below the claw tip relative to the target surface, the digging state of the bucket 22 can be maintained. It should be noted that, while maintaining the friction state, the same process can be performed by reversing the vertical relationship between the rear end and claw tip of the bucket 22.

[0092] Unlike the above, if the angle of the bucket 22 changes drastically from the initial angle at the start of bucket operation, it may cause discomfort to the operator. Therefore, by setting a limit value for the angle correction of the bucket 22 relative to the initial angle in advance, the operator's discomfort can be reduced and the workability improved. Furthermore, abrupt changes in the angle of the bucket 22 may also cause discomfort to the operator. Therefore, an upper limit value can also be set in advance for the operating speed or angular velocity of the bucket cylinder 22A. Additionally, the upper limit value for the operating speed of the bucket cylinder 22A can be changed according to the operating speed of the front part 2. These values ​​are related to the operator's discomfort, so it is preferable to determine them through experiments, etc.

[0093] In addition, when it is desired to keep the angle of the bucket 22 relative to the construction target surface constant, by setting the aforementioned angle limit and angular velocity limit for the target holding angle of the bucket 22, it is possible to reduce the distance between the bucket 22 and the construction target surface while keeping the angle of the bucket 22 relative to the construction target surface within a constant range.

[0094] <Bucket Movement Trajectory>

[0095] In the case of using existing machine tool control technology, such as Figure 10A As shown, because the attitude of the bucket 22 relative to the target surface is not considered when correcting the movement of the bucket 22, causing the claw tip of the bucket 22 to follow the target surface, there is a possibility that the working state of the bucket 22 may change midway through a series of movements in the initial stage 2 of the operation. For example, although as... Figure 10A When working in digging mode, if the rear end of the bucket 22 is below the claw tip during a series of movements, the bucket 22 cannot perform digging operations at the claw tip. Similarly, even when working in friction mode, if the claw tip of the bucket 22 is below the rear end during a series of movements, the bucket 22 cannot perform friction operations at the rear end.

[0096] On the other hand, when using the machine tool control described in this embodiment, such as Figure 10B As shown, when the claw tip of the bucket 22 is below the target surface, the movement of the bucket 22 is restricted to prevent the bottom surface of the bucket 22 from being below the claw tip, and the movement of the bucket 22 is corrected so that the claw tip of the bucket 22 approaches the target surface. Therefore, in a series of movements of the working front 2, the workability of the hydraulic excavator 1 is improved because it can maintain the working state of the bucket 22 in accordance with the operator's intention while following the target surface.

[0097] It should be noted that, Figure 10A and Figure 10B The image showing the relationship between the size of the bucket 22 and the bucket trajectory is for illustrative purposes and does not reflect the actual proportions.

[0098] <Control Steps>

[0099] Figure 11 This is a flowchart illustrating the processing content of the information processing device 34. The steps are described below in sequence.

[0100] In step S110, the attitude of the front part 2 and the rotating body 3 is calculated based on the signal obtained from the attitude detection device 30.

[0101] In step S120, the distance between the bucket 22 and the target surface is calculated.

[0102] In step S130, the target speed of the working front 2 is calculated based on the posture of the working front 2 and the rotating body 3, the distance between the bucket 22 and the construction target surface, and the operation input from the operation input device 33.

[0103] In step S140, the condition for maintaining the bucket angle is determined based on the posture of the working front part 2 and the rotating body 3, the positional relationship between the bucket 22 and the target surface, and the operation input from the operation input device 33. The bucket angle maintaining condition here is used to determine whether it is necessary to maintain the angle of the bucket 22 relative to the target surface. For example, it is when the distance between the bucket 22 and the target surface is below a specified value and the operation of the working front part 2 is indicated. If the bucket angle maintaining condition is met, the process proceeds to step S150; if the bucket angle maintaining condition is not met, the process proceeds to step S185.

[0104] In step S150, the travel direction of the bucket 22 is determined based on the target speed and target surface information of the front part 2. Specifically, if the velocity component of the target speed of the bucket 22 that is parallel to the target surface and towards the claw tip is greater than the velocity component that is perpendicular to the target surface, the travel direction of the bucket 22 is calculated to be towards the claw tip; if the velocity component of the target speed of the bucket 22 that is parallel to the target surface and towards the rear end is greater than the velocity component that is perpendicular to the target surface, the travel direction of the bucket 22 is calculated to be towards the rear end.

[0105] In step S160, the operating state of the bucket 22 is determined based on the distance between the bucket 22 and the construction target surface calculated in step S120 and the travel direction of the bucket 22 determined in step S150. If the operating state of the bucket 22 is digging, the process proceeds to step S170; if it is friction, the process proceeds to step S175.

[0106] In step S170, a bucket correction limit value for maintaining the digging state of the bucket 22 is calculated.

[0107] In step S175, the bucket correction limit value for maintaining the friction state of the bucket 22 is calculated.

[0108] In step S180, if the movement correction amount of the bucket 22 does not exceed the bucket correction limit value calculated in step S170 or step S175, the target speed of the bucket 22 is corrected so that the distance between the bucket 22 and the construction target surface is reduced.

[0109] In step S185, the target speed of the bucket 22 is not corrected.

[0110] In step S190, it is determined whether the target speed of the bucket 22 corresponding to the operation input amount from the operation input device 33 is less than the target speed calculated in step S180 or step S185. If the operation input amount from the operation input device 33 is less than the target action calculated in step S180 or step S185, the process proceeds to step S210; if the target speed corresponding to the operation input amount from the operation input device 33 is greater than or equal to the target speed calculated in step S180 or step S185, the process proceeds to step S200.

[0111] In step S200, the target speed of the bucket 22 is corrected based on the operation input amount from the operation input device 33.

[0112] In step S210, the action command value is calculated based on the target speed of the bucket 22 and output to the drive device 35.

[0113] (Summarize)

[0114] In this embodiment, the working machine 1 includes: a main body 3; a front working part 2 having a working tool 22, which is flexibly mounted on the main body 3 in the vertical direction; actuators 20A, 21A, and 22A that drive the front working part 2; a drive device 35 that drives the actuators 20A, 21A, and 22A; an operation input device 33 that instructs the actions of the actuators 20A, 21A, and 22A; a posture detection device 30 that detects the posture of the main body 3 and the front working part 2; a target surface information setting device 100 that sets the target surface as the excavation object of the working tool 22; and a controller 34a that is based on the input from the operation input device 33. The information input from the attitude detection device 30 and the target surface information setting device 100 is used to calculate the action command values ​​of the actuators 20A, 21A, and 22A, and output to the drive device 35, causing the working tool 22 to move along the target surface. The controller 34a determines the working state of the working tool 22 based on the operation input quantity input from the operation input device 33 and the attitude of the working tool relative to the target surface 22. Furthermore, it calculates the range of action command values ​​of the actuators 20A, 21A, and 22A that maintain the determined working state, and corrects the action command values ​​of the actuators within the range, thereby reducing the distance between the working tool 22 and the target surface. It should be noted that in this embodiment, the action command values ​​of the actuators 20A, 21A, and 22A are indirectly corrected by correcting the target speed of the bucket 22, or the action command values ​​of the actuators 20A, 21A, and 22A can be directly corrected.

[0115] In this embodiment constructed as described above, the workability of the hydraulic excavator 1 can be improved by maintaining the working state of the working tool 22 in accordance with the operator's intention in machine tool control that makes the working tool 22 follow the construction target surface.

[0116] Furthermore, in this embodiment, the controller 34a determines the operating state of the work tool 22 when the distance between the work tool 22 and the target surface becomes below a predetermined value, and when the velocity component parallel to the target surface in the target velocity of the work tool 22 calculated based on the operation input is greater than the velocity component perpendicular to the target surface. Therefore, the operating state of the work tool 22 can be determined at the precise time when it begins operation.

[0117] Furthermore, in this embodiment, the controller 34a determines the working state of the working tool 22 based on the attitude and direction of travel of the working tool relative to the target surface 22. This improves the accuracy of determining the working state of the working tool 22.

[0118] Furthermore, in this embodiment, the controller 34a detects the attitude of the working tool relative to the target surface 22 based on the distances between two pre-set points (a point on the claw tip side and a point on the rear end side) on the working tool 22 and the target surface. This allows for simple detection of the attitude of the working tool relative to the target surface 22.

[0119] Furthermore, in this embodiment, the working tool 22 is a bucket. The controller 34a determines the working state of the bucket 22 as digging when, with the target surface as a reference, the claw tip of the bucket 22 is below the rear end of the bucket 22, and the velocity component of the target velocity of the bucket 22 that is parallel to the target surface and towards the claw tip is greater than the velocity component perpendicular to the target surface. Alternatively, when, with the target surface as a reference, the claw tip is below the rear end of the bucket 22, and the velocity component of the target velocity of the bucket 22 that is parallel to the target surface and towards the rear end is greater than the velocity component perpendicular to the target surface; or when, with the target surface as a reference, the rear end is below the claw tip, and the velocity component of the target velocity of the bucket 22 that is parallel to the target surface is greater than the velocity component perpendicular to the target surface, the working state of the bucket 22 is determined as friction. Therefore, in the hydraulic excavator 1 equipped with the bucket 22 as a working tool, it is possible to accurately determine whether the working state of the bucket 22 is digging or friction.

[0120] Furthermore, in this embodiment, when the controller 34a determines that the working state of the bucket 22 is digging, it corrects the action command values ​​of the actuators 20A, 21A, and 22A within the range of action command values ​​that maintain the claw tip below the rear end relative to the target surface, thereby reducing the distance from the claw tip to the target surface. Similarly, when the controller 34a determines that the working state of the bucket 22 is friction, it corrects the action command values ​​of the actuators 20A, 21A, and 22A within the range of action command values ​​that maintain the rear end below the claw tip relative to the target surface, thereby reducing the distance from the claw tip to the target surface. Thus, in machine tool control that enables the bucket 22 to follow the target surface, by maintaining the working state (digging or friction) of the bucket 22 in accordance with the operator's intention, the operability of the hydraulic excavator 1 can be improved.

[0121] Furthermore, in this embodiment, the controller 34a corrects the motion command values ​​of the actuators 20A, 21A, and 22A to ensure that the angle change of the working tool 22 does not exceed a preset angle correction limit, or that the angular velocity change of the working tool 22 does not exceed a preset angular velocity correction limit. Therefore, since the change in the posture of the working tool 22 during operation is suppressed to a certain level, the operator's discomfort is reduced.

[0122] Furthermore, in this embodiment, the controller 34a calculates the angle correction limit or angular velocity correction limit value of the working tool 22 based on the movement speed of the working front part 2, and corrects the action command values ​​of the actuators 20A, 21A, and 22A to ensure that the angle change of the working tool 22 does not exceed the angle correction limit value, or the angular velocity change of the working tool 22 does not exceed the angular velocity correction limit value. Therefore, the change in the posture of the working tool 22 during operation can be suppressed according to the movement speed of the working front part 2, thus further reducing the operator's discomfort.

[0123] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments and includes various modifications. For example, the above detailed description of the embodiments is for the purpose of making the present invention clear and easy to understand, and is not limited to having all the described configurations.

[0124] Explanation of reference numerals in the attached figures

[0125] 1…Hydraulic excavator (operating machinery), 2…Working front, 3…Rotating body (machine body), 4…Traveling body, 10…Control system, 20…Boom, 20A…Boom cylinder (actuator), 20S…Boom IMU, 21…Stick, 21A…Stick cylinder (actuator), 21S…Stick IMU, 22…Bucket (operating tool), 22A…Bucket cylinder (actuator), 22B…First link, 22C…Second link, 22S…Bucket IMU, 30S…Rotating body IMU, 31…Main frame, 32…Cab, 33…Operating input device, 34…Information processing device, 35…Drive device, 36…Primary drive device, 37…Equipped with… 38… Rotary motor (actuator), 40… Track frame, 41… Traveling motor (actuator), 45… Track, 100… Target surface information setting device, 100a… Target surface information setting controller, 110… Display setting device, 110a… Display monitor, 110b… Touch panel, 210… Attitude calculation unit, 220… Target surface distance calculation unit, 310… Target speed calculation unit, 410… Bucket angle control determination unit, 420… Bucket travel direction determination unit, 430… Bucket operating status determination unit, 440… Bucket correction limit value calculation unit, 450… Bucket target speed correction unit, 610… Action command value calculation unit.

Claims

1. A work machine comprising: a machine body; a work front portion having a work tool swingably mounted to the machine body in a vertical direction; an actuator that drives the work front portion; a drive device that drives the actuator; an operation input device that indicates an action of the actuator; a posture detection device that detects postures of the machine body and the work front portion; a target surface information setting device that sets a target surface that is a digging target of the work tool; and a controller that calculates an action command value of the actuator based on information input from the operation input device, the posture detection device, and the target surface information setting device and outputs to the drive device so that the work tool moves along the target surface, characterized in that the controller determines a work state of the work tool based on an operation input amount input from the operation input device and a posture of the work tool with respect to the target surface, and calculates a range of the action command value of the actuator that maintains the determined work state, and corrects the action command value of the actuator within the range so that a distance of the work tool from the target surface decreases, the work tool is a shovel, in terms of the controller, in a case where a claw tip of the shovel is located lower than a rear end side of the shovel with the target surface as a reference, and a velocity component of a moving speed of the shovel that is parallel to the target surface and toward the claw tip side is greater than a velocity component that is perpendicular to the target surface, the work state of the shovel is determined to be a digging state, and in a case where the claw tip is located lower than the rear end side with the target surface as the reference, and the velocity component of the moving speed of the shovel that is parallel to the target surface and toward the rear end side is greater than the velocity component that is perpendicular to the target surface, or in a case where the rear end side is located lower than the claw tip with the target surface as the reference, and a velocity component of the moving speed of the shovel that is parallel to the target surface is greater than the velocity component that is perpendicular to the target surface, the work state of the shovel is determined to be a friction state.

2. The work machine according to claim 1, characterized in that the controller determines the work state of the work tool at a timing when a distance of the work tool from the target surface becomes a prescribed value or less, and a velocity component of a target speed of the work tool that is parallel to the target surface based on the operation input amount is greater than a velocity component that is perpendicular to the target surface.

3. The work machine according to claim 1, characterized in that the controller determines the work state of the work tool based on a posture of the work tool with respect to the target surface and a traveling direction.

4. The work machine according to claim 3, characterized in that the controller detects the posture of the work tool with respect to the target surface based on distances of two points that are set in advance on the work tool from the target surface.

5. The work machine according to claim 1, characterized in that in terms of the controller, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ In a case where the working state of the shovel is determined to be the digging state, within a range of the operation command value in which the claw tip is maintained below the rear end side with reference to the target surface, the operation command value of the actuator is corrected so that the distance of the claw tip from the target surface is reduced, In a case where the working state of the shovel is determined to be the friction state, within a range of the operation command value in which the rear end side is maintained below the claw tip with reference to the target surface, the operation command value of the actuator is corrected so that the distance of the claw tip from the target surface is reduced.

6. The working machine according to claim 1, characterized in that the controller corrects the operation command value of the actuator so that the angle change amount of the working tool does not exceed a predetermined angle correction limit value, or so that the angular velocity change amount of the working tool does not exceed a predetermined angular velocity correction limit value.

7. The working machine according to claim 1, characterized in that in terms of the controller, the angle correction limit value or the angular velocity correction limit value of the working tool is calculated based on the operation speed of the working front, the operation command value of the actuator is corrected so that the angle change amount of the working tool does not exceed the angle correction limit value, or so that the angular velocity change amount of the working tool does not exceed the angular velocity correction limit value.

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