JP6991056B2 - Excavator - Google Patents

Description

This disclosure relates to excavators.

During excavator excavation work, the lower traveling body of the excavator may be lifted by the reaction force that the attachment receives from the ground. To solve this problem, for example, in Patent Document 1, the maximum value of the force of the boom cylinder when the excavator is lifted by the excavation reaction force is calculated based on the posture of the excavator (boom angle, arm angle, bucket angle). A method of controlling the force of the boom cylinder so as not to exceed the maximum value is disclosed.

Japanese Unexamined Patent Publication No. 2014-122510

However, in order to suitably suppress the operation of the excavator that is not intended by the operator, including the floating operation, it is desirable that these operations can be determined with higher accuracy.

It is an object of the present disclosure to provide an excavator capable of accurately determining an unintended operation of an operator.

The excavator according to one aspect of the embodiment includes a lower traveling body, an upper swivel body rotatably mounted on the lower traveling body, an attachment mounted on the upper swivel body, and an actuator for driving the attachment. An acceleration detection unit that is attached to the upper swing body or the attachment and detects the acceleration of the upper swing body while the lower traveling body is traveling, and the lower portion based on the direction of the acceleration detected by the acceleration detection unit. It is provided with a turning angle calculation unit for calculating the relative turning angle of the upper turning body with respect to the traveling body.

According to the present disclosure, it is possible to provide an excavator capable of accurately determining an operation not intended by an operator.

It is a side view of the excavator which concerns on embodiment. It is a block diagram which shows an example of the structure centering on the drive system of the excavator of FIG. It is a flowchart which shows the outline of the stabilization control performed by a controller. It is a figure explaining the front lifting operation of an excavator. It is a figure explaining the rear lifting operation of an excavator. It is a figure which shows the mechanical model of the excavator which is related to the front lifting motion. It is a figure which shows the mechanical model of the excavator related to the rear lift. It is a figure which shows the relationship between the floating fulcrum and the direction of the upper swing body. It is a flowchart which shows an example of the suppression control of a floating operation. It is a figure explaining the situation which the vibration operation occurs at the time of the aerial operation of an excavator. It is a figure which shows the time waveform of the angle (pitch angle) and the angular velocity (pitch angular velocity) in the pitching axis direction with the discharge operation of the excavator in the situation shown in FIG. It is a figure which shows an example of the stability display of a display device. It is a figure which shows another example of the stability display of a display device. It is a flowchart which shows the other example of the suppression control of a floating operation. It is a figure explaining an example of the calibration method of the acceleration detection part.

Hereinafter, embodiments will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components are designated by the same reference numerals as possible in the drawings, and duplicate description is omitted.

[Overview of excavator]
First, the outline of the excavator 100 according to the embodiment will be described with reference to FIG. FIG. 1 is a side view of the shovel 100 according to the embodiment.

The excavator 100 according to the present embodiment includes a lower traveling body 1, an upper rotating body 3 that is rotatably mounted on the lower traveling body 1 via a turning mechanism 2, a boom 4, an arm 5, and a bucket 6 as attachments. And a cabin 10 on which the operator is boarded.

The lower traveling body 1 includes, for example, a pair of left and right crawlers, and each crawler is hydraulically driven by traveling hydraulic motors 1A and 1B (see FIG. 2 and the like) to drive the excavator 100.

The upper swing body 3 turns with respect to the lower traveling body 1 by being driven by a swing hydraulic motor 21 (see FIG. 2) or the like, which will be described later.

The boom 4 is pivotally attached to the center of the front part of the upper swing body 3 so as to be upright, an arm 5 is pivotally attached to the tip of the boom 4 so as to be vertically rotatable, and a bucket 6 is vertically attached to the tip of the arm 5. Rotatably pivoted. The boom 4, arm 5, and bucket 6 are each hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 as hydraulic actuators, respectively.

The cabin 10 is a cockpit on which the operator is boarded, and is mounted on the front left side of the upper swivel body 3.

[Basic structure of excavator]
Next, the configuration of the excavator 100 of FIG. 1 will be described in detail with reference to FIG. FIG. 2 is a block diagram showing an example of a configuration centered on the drive system of the excavator 100 of FIG. In FIG. 2, the mechanical power system is shown by a double line, the high-pressure hydraulic line is shown by a thick solid line, the pilot line is shown by a broken line, and the electric drive / control system is shown by a thin solid line.

The hydraulic drive system of the excavator 100 according to the present embodiment includes an engine 11, a main pump 14, and a control valve 17. Further, as described above, the hydraulic drive system according to the present embodiment includes traveling hydraulic motors 1A and 1B for hydraulically driving each of the lower traveling body 1, the upper turning body 3, the boom 4, the arm 5, and the bucket 6 and the turning hydraulic pressure. It includes a motor 21, a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9.

The engine 11 is a driving force source for the excavator 100, and is mounted on the rear portion of the upper swing body 3, for example. The engine 11 is, for example, a diesel engine that uses light oil as fuel. A main pump 14 and a pilot pump 15 are connected to the output shaft of the engine 11.

The main pump 14 is mounted on the rear portion of the upper swing body 3, for example, and supplies hydraulic oil to the control valve 17 through the high-pressure hydraulic line 16. The main pump 14 is driven by the engine 11 as described above. The main pump 14 is, for example, a variable displacement hydraulic pump, and the stroke length of the piston is adjusted and the discharge flow rate (discharge pressure) is controlled by controlling the angle (tilt angle) of the swash plate by the regulator. be able to.

The control valve 17 is, for example, a hydraulic control device mounted on the central portion of the upper swing body 3 and controls the hydraulic drive system in response to the operation of the operation device 26 by the operator. The traveling hydraulic motor 1A (for right), 1B (for left), boom cylinder 7, arm cylinder 8, bucket cylinder 9, swivel hydraulic motor 21, and the like are connected to the control valve 17 via a high-pressure hydraulic line. The control valve 17 is provided between the main pump 14 and each hydraulic actuator, and includes a plurality of hydraulic control valves that control the flow rate and flow direction of the hydraulic oil supplied from the main pump 14 to each hydraulic actuator. It is a unit.

The operation system of the excavator 100 according to the present embodiment includes a pilot pump 15, an operation device 26, a pressure sensor 29, and the like.

The pilot pump 15 is mounted on the rear portion of the upper swing body 3, for example, and supplies the pilot pressure to the mechanical brake 23 and the operating device 26 via the pilot line 25. The pilot pump 15 is, for example, a fixed-capacity hydraulic pump, and is driven by the engine 11 as described above.

The operating device 26 includes lever devices 26A and 26B and a pedal device 26C. The operating device 26 is provided near the cockpit of the cabin 10 and is an operating means for the operator to operate each operating element (lower traveling body 1, upper swivel body 3, boom 4, arm 5, bucket 6, etc.). In other words, the operating device 26 operates the hydraulic actuators (traveling hydraulic motors 1A, 1B, boom cylinder 7, arm cylinder 8, bucket cylinder 9, swivel hydraulic motor 21) that drive each operating element. It is a means. The operating device 26 (lever device 26A, 26B, and pedal device 26C) is connected to the control valve 17 via the hydraulic line 27. As a result, a pilot signal (pilot pressure) according to the operating state of the lower traveling body 1, the upper swivel body 3, the boom 4, the arm 5, the bucket 6 and the like in the operating device 26 is input to the control valve 17. Therefore, the control valve 17 can drive each hydraulic actuator according to the operating state of the operating device 26. Further, the operating device 26 is connected to the pressure sensor 29 via the hydraulic line 28.

The lever devices 26A and 26B are arranged on the left and right sides when viewed from the operator seated in the cockpit in the cabin 10, respectively, and the respective operating levers are arranged in a neutral state (a state in which there is no operation input by the operator) as a reference. It is configured to be able to tilt in the front-back direction and the left-right direction. As a result, the upper swivel body 3 with respect to the tilting of the operating lever in the front-rear direction and the left-right direction in the lever device 26A, the tilting in the front-rear direction and the tilting in the left-right direction of the operating lever in the lever device 26B, respectively. Any one of (swivel hydraulic motor 21), boom 4 (boom cylinder 7), arm 5 (arm cylinder 8), and bucket 6 (bucket cylinder 9) can be arbitrarily set as an operation target.

Further, the pedal device 26C targets the lower traveling body 1 (traveling hydraulic motors 1A and 1B) as an operation target, and is arranged on the front floor when viewed from the operator seated in the cockpit in the cabin 10, and the operation pedal is arranged on the front floor. It is configured so that it can be stepped on by the operator.

As described above, the pressure sensor 29 is connected to the operating device 26 via the hydraulic line 28, and is the pilot pressure on the secondary side of the operating device 26, that is, the pilot pressure corresponding to the operating state of each operating element in the operating device 26. Is detected. The pressure sensor 29 is connected to the controller 30, and a pressure signal (pressure detection value) according to the operating state of the lower traveling body 1, the upper swivel body 3, the boom 4, the arm 5, the bucket 6 and the like in the operating device 26 is the controller. It is input to 30. As a result, the controller 30 can grasp the operating state of the lower traveling body 1, the upper turning body 3, and the attachment of the excavator.

The control system of the excavator 100 according to the present embodiment includes a controller 30, an acceleration detection unit 31, various sensors 32, and the like.

The controller 30 is a main control device that controls the drive of the excavator 100. The controller 30 may be realized by any hardware, software, or a combination thereof. The controller 30 is mainly composed of a microcomputer including, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an auxiliary storage device, an I / O (Input-Output interface), and the like. Therefore, various drive controls are realized by executing various programs stored in a ROM, an auxiliary storage device, or the like on the CPU.

The controller 30 calculates the relative turning angle θ of the upper turning body 3 with respect to the lower traveling body 1 based on the direction of acceleration of the upper turning body 3, and based on the calculated turning angle θ, the operator does not intend the excavator. When the unstable state of the shovel 100 in which the operation of 100 (unintended operation) can occur is detected, the stabilization control of the shovel 100 is performed.

FIG. 3 is a flowchart showing an outline of the stabilization control performed by the controller 30.

In step S1, it is determined whether or not the lower traveling body 1 of the excavator 100 is traveling. If the excavator 100 is running (Yes in step S1), the process proceeds to step S2, and if the shovel 100 is not running (No in step S01), the process proceeds to step S4.

In step S2, since the lower traveling body 1 is traveling, the acceleration AC of the upper rotating body 3 while the lower traveling body 1 is traveling is detected. When the process of step S2 is completed, the process proceeds to step S3.

In step S3, the relative turning angle θ of the upper turning body 3 with respect to the lower traveling body 1 is calculated based on the direction of the acceleration AC detected in step S2. When the process of step S3 is completed, the controller 30 stores the calculated information on the turning angle θ and ends the control flow.

In step S4, since it is determined in step S1 that the lower traveling body 1 is not traveling, it is determined whether or not the excavator 100 is operating the attachment. The attachment operation refers to work other than running the excavator 100 (for example, excavation or aerial operation of the attachment). If the excavator 100 is operating the attachment (Yes in step S4), the process proceeds to step S5, and if not (No in step S5), the control flow ends.

In step S5, since it is determined in step S4 that the attachment is being operated, it is determined whether or not the shovel 100 is in an unstable state. The criterion for determining the unstable state varies according to the turning angle θ of the upper turning body 3 calculated in step S3. If the excavator 100 is in an unstable state (Yes in step S5), the process proceeds to step S6, and if not (No in step S5), the control flow is terminated.

In step S6, since it was determined in step S5 that the shovel 100 is in an unstable state, stabilization control is performed in order to eliminate the unstable state. Stabilization control includes, for example, display of stability, suppression of force generation, reduction of hydraulic pump horsepower (pressure, flow rate, etc.), boom relief (absorbing reaction force to the vehicle body by a boom cylinder), and the like.

In step S7, the operator is notified of the occurrence of the unstable state via the display device 33. When the process of step S7 is completed, this control flow ends.

In the present embodiment, the controller 30 determines whether or not a floating operation occurs among the operations of the shovel 100 that the operator does not intend. Then, when it is determined that such a floating operation has occurred, the controller 30 corrects the operation of the attachment of the excavator 100 or notifies the operator so as to suppress the operation. As a result, the unintended operation generated in the excavator 100 is suppressed.

The lifting motion includes, for example, a lifting motion in which the front portion or the rear portion of the excavator 100 is lifted by an excavation reaction force or the like. Hereinafter, among the lifting motions, the case where the front portion of the excavator 100 is lifted may be referred to as "front lifting motion", and the case where the rear portion of the shovel 100 is lifted may be referred to as "rear lifting motion".

The controller 30 has, for example, a turning angle calculation unit 301, a floating fulcrum estimation unit 302, and a distance calculation as functional units realized by executing one or more programs stored in a ROM or an auxiliary storage device on the CPU. A unit 303, a determination unit 304, an upper limit value setting unit 305, and an operation correction unit 306 are included.

The turning angle calculation unit 301 calculates the relative turning angle θ of the upper turning body 3 with respect to the lower traveling body 1 based on the direction of the acceleration of the upper turning body 3 detected by the acceleration detecting unit 31. For example, the turning angle calculation unit 301 may obtain the acceleration from the information related to the acceleration, the speed, the position, and the like, or may directly obtain θ from the information related to the acceleration.

The floating fulcrum estimation unit 302 has a floating fulcrum P1f of the lower traveling body 1 in the front floating operation and a floating fulcrum P1r of the lower traveling body 1 in the rear floating operation based on the turning angle θ calculated by the turning angle calculation unit 301. (See FIGS. 6 and 7).

The distance calculation unit 303 is located between the vehicle center of gravity P3 of the shovel 100 and the lift fulcrum P1f, P1r of the lower travel body 1 based on the lift fulcrum P1f, P1r of the lower traveling body 1 estimated by the lift fulcrum estimation unit 302. Calculate the distances D1 and D2 (see FIGS. 6 and 7). Further, the distance calculation unit 303 calculates the distances D3 and D4 between the extension line l2 of the boom cylinder 7 and the floating fulcrum P1 based on the angles of the floating fulcrums P1f and P1r of the lower traveling body 1 and the boom cylinder 7. (See FIGS. 6 and 7).

The determination unit 304 is based on the information of the distances D1 to D4 calculated by the distance calculation unit 303, the force F1 generated by the boom cylinder 7 (actuator), or the information on various states of the excavator 100 input from the various sensors 32. , It is determined whether or not the lower traveling body 1 has been lifted.

The upper limit value setting unit 305 is based on the distances D1 to D4 calculated by the distance calculation unit 303, and the upper limit value F1max of the force (or cylinder pressure) generated by the boom cylinder 7 (actuator) within the range where the lower traveling body 1 does not rise. To set.

The motion correction unit 306 controls the force F1 of the boom cylinder 7 (actuator) so as not to exceed the upper limit value F1max set by the upper limit value setting unit 305, corrects the operation of the attachment, and suppresses the floating operation. ..

The acceleration detection unit 31 detects the acceleration of the upper swivel body 3. The acceleration detection unit 31 includes, for example, a gyro sensor, an acceleration sensor, an IMU (Inertial Measurement Unit) capable of outputting triaxial acceleration and triaxial angular acceleration, and the like. The acceleration detection unit 31 is attached to the upper swing body 3 in this embodiment.

The various sensors 32 are known detection means for detecting various states of the shovel 100 and various states around the shovel 100. The various sensors 32 have an angle (boom angle) of the boom 4 with respect to the reference plane at the connection point between the upper swing body 3 and the boom 4, a relative angle between the boom 4 and the arm 5 (arm angle), and An angle sensor may be included that detects the relative angle (bucket angle) between the arm 5 and the bucket 6. Further, the various sensors 32 may include a pressure sensor for detecting the hydraulic pressure state in the hydraulic actuator, specifically, the pressure in the rod side oil chamber and the bottom side oil chamber of the hydraulic cylinder. Further, the various sensors 32 may include a distance sensor, an image sensor, and the like for detecting the relative positional relationship with the terrain around the shovel 100, obstacles, and the like.

The display device 33 (notification unit) is a device for displaying various information, and is, for example, a liquid crystal display installed in the driver's cab of a shovel. The display device 33 displays various information according to the control signal from the controller 30. In the present embodiment, the display device 33 notifies the occupant of the occurrence of the floating operation when the determination unit 304 of the controller 30 determines that the floating operation will occur.

[Front lifting motion]
FIG. 4 is a diagram illustrating a front lifting operation of the excavator 100. Specifically, FIG. 4 is a diagram showing a working situation of the shovel 100 in which the front lifting operation occurs.

As shown in FIG. 4, the excavator 100 is excavating the ground 50a, and mainly due to the closing operation of the arm 5 and the bucket 6, the excavator 100 is moved diagonally downward from the bucket 6 to the ground 50a toward the vehicle body. Force F2 acts. At this time, on the vehicle body of the excavator 100, the reaction force of the force F2 acting on the bucket 6, that is, the reaction force F3 (that is, the reaction force F3 that tries to tilt the vehicle body corresponding to the vertical component F2aV of the excavation reaction force F2a backward). A moment of force, hereinafter simply referred to as a "moment" in this embodiment) acts via an attachment. Specifically, the reaction force F3 acts on the vehicle body as a force F1 for pulling up the boom cylinder 7. Then, when the moment for tilting the vehicle body backward due to this force F1 exceeds the force (moment) for suppressing the vehicle body based on gravity to the ground, the front portion of the vehicle body is lifted.

[Rear lift movement]
FIG. 5 is a diagram illustrating a rear lifting operation of the shovel 100. Specifically, FIG. 5 is a diagram showing a working situation of the shovel 100 in which the rear lifting operation occurs.

As shown in FIG. 5, the excavator 100 is excavating the ground 60a. A force F2 (moment) is generated so that the bucket 6 digs into the slope 60b, and the boom 4 suppresses the bucket 6 to the slope 60b, in other words, the boom 4 tilts the vehicle body forward. In addition, a force F3 (moment) is generated. At this time, a force F1 that pulls up the rod of the boom cylinder 7 is generated, and the force F1 acts to tilt the vehicle body of the shovel 100. Then, when the moment for tilting the vehicle body forward due to the force F1 exceeds the force (moment) for suppressing the vehicle body based on gravity to the ground, the rear portion of the vehicle body is lifted.

In particular, when the bucket 6 is in contact with the ground or an object and is caught or sunk, the boom 4 does not move even if a force acts on the boom 4, so that the rod of the boom cylinder 7 does not displace. When the pressure in the oil chamber on the contraction side (in this example, the rod side) of the boom cylinder 7 becomes large, the force F1 for lifting the boom cylinder 7 itself, that is, the force for tilting the vehicle body forward becomes large.

Such a situation may occur, for example, in the ground leveling work on the front slope, or in the deep digging work in which the bucket 6 is located below the vehicle body (lower traveling body 1). Further, it may occur not only when the boom 4 itself is operated but also when the arm 5 and the bucket 6 are operated.

[Method of suppressing floating movement]
FIG. 6 is a diagram showing a mechanical model of the excavator 100 related to the front lifting motion, and as in FIG. 4, the force acting on the excavator 100 when the excavator 100 is excavating the ground 120a. It is a figure which shows.

As shown in FIG. 6, the lifting fulcrum P1f in the front lifting operation of the excavator 100 is the rearmost end in the effective ground contact area 120b of the lower traveling body 1 in the direction in which the attachment extends (direction of the upper turning body 3). Can be regarded. Therefore, the moment τ1 for lifting the front part of the vehicle body around the floating fulcrum P1f is calculated by the following equation (1) based on the distance D3 between the extension line l2 of the boom cylinder 7 and the floating fulcrum P1f and the force F1. expressed.

τ1 = D3 ・ F1 ・ ・ ・ (1)

On the other hand, the moment τ2 in which gravity tries to hold the vehicle body against the ground around the floating fulcrum P1f is the distance D1 between the vehicle weight center P3 of the excavator 100 and the floating fulcrum P1f behind the lower traveling body 1 and the vehicle body weight. Based on M and the gravitational acceleration g, it is expressed by the following equation (2).

τ2 = D1 · Mg ... (2)

The condition (stability condition) in which the front part of the vehicle body is stable without rising is expressed by the following equation (3).

τ1 <τ2 ... (3)

Therefore, by substituting the equations (1) and (2) into the equation (3), the following inequality equation (4) can be obtained as a stability condition.

D3 ・ F1 <D1 ・ Mg ・ ・ ・ (4)

That is, the determination unit 304 can determine that the front floating motion has not occurred when the inequality (4) holds, and can determine that the front lifting motion has occurred when the inequality (4) does not hold. Further, the motion correction unit 306 can prevent the front floating motion of the excavator 100 by correcting the motion of the attachment so that the inequality (4) holds as a control condition.

FIG. 7 is a diagram showing a mechanical model of the excavator 100 related to the rear lift, and is a diagram showing a force acting on the excavator 100 when excavating the ground 130a, as in FIG. 5. ..

The lift fulcrum P1r in the rear lift operation of the excavator 100 can be regarded as the most advanced position in the effective ground contact area 130b of the lower traveling body 1 in the direction in which the attachment extends (direction of the upper swing body 3). Therefore, the moment τ1 that tries to tilt the vehicle body forward around the floating fulcrum P1, that is, the moment τ1 that tries to lift the rear part of the vehicle body is the distance D4 between the extension line l2 of the boom cylinder 7 and the floating fulcrum P1r. It is expressed by the following equation (5) based on the force F1 exerted by the boom cylinder 7 on the upper swing body 3.

τ1 = D4 ・ F1 ・ ・ ・ (5)

On the other hand, the moment τ2 in which gravity tries to hold the vehicle body against the ground around the floating fulcrum P1r is the distance D2 between the vehicle weight center P3 of the excavator, the floating fulcrum P1r in front of the lower traveling body 1, and the vehicle body weight M. , Based on the gravitational acceleration g, it is expressed by the following equation (6).

τ2 = D2 ・ Mg ・ ・ ・ (6)

The condition (stability condition) in which the rear part of the vehicle body is stabilized without rising is expressed by the following equation (7) as in the equation (3).

τ1 <τ2 ... (7)

Therefore, by substituting the equations (5) and (6) into the equation (7), the following inequality equation (8) can be obtained as a stability condition.

D4 ・ F1 <D2 ・ Mg ・ ・ ・ (8)

That is, the determination unit 304 can determine that the rear floating operation has not occurred when the inequality (8) holds, and can determine that the rear lifting operation has occurred when the inequality (8) does not hold. Further, if the motion correction unit 306 corrects the motion of the attachment so that the inequality (8) holds as a control condition, the rear floating motion of the shovel 100 can be prevented.

[Method of suppressing lifting motion considering changes in lifting fulcrum]
Hereinafter, a method of suppressing the floating operation in consideration of the change of the floating fulcrum will be described with reference to FIG. FIG. 8 is a diagram showing the relationship between the floating fulcrums P1f and P1r and the orientation of the upper swing body 3.

As described above, the control conditions (stability conditions) in which the front lift and the rear lift do not occur are the inequalities (4) and (8). Inequalities (4) and (8) have distances D1, D2, D3, and D4 as parameters, and these distances depend on the positions of the floating fulcrums P1f and P1r.

In FIG. 8, when the direction in which the attachment extends (the direction of the attachment) and the direction of the lower traveling body 1 (the traveling direction) are the same, the turning angle θ = 0 °, and the right turning is the positive direction. It is a figure explaining the relationship between the fulcrum P1r and the direction (turning angle θ) of the upper swing body 3. Specifically, FIGS. 8A to 8C are diagrams showing the floating fulcrum P1 when the turning angle θ is 0 °, 30 °, and 90 °, respectively.

In FIGS. 8A to 8C, the floating fulcrum P1r is located at the front part of the vehicle body on the assumption that the rear part is lifted. Further, the line l1 in FIGS. 8A to 8C is orthogonal to the direction in which the attachment extends (the direction of the upper swivel body 3), and is the most in the extending direction of the attachment in the effective ground contact area 140a. It represents a line passing through the tip, and the floating fulcrum P1r is located on the line l1.

As shown in FIG. 8, the floating fulcrum P1r moves according to the direction of the upper swivel body 3 and the state of the ground. For example, as shown in FIGS. 8A to 8C, when the floating fulcrum P1 moves, the distance D2 also changes. Similarly, the distance D4 also changes with the movement of the floating fulcrum P1r.

The movement of the floating fulcrum P1r affects the distances D2 and D4, and affects the mechanical stability conditions under which the vehicle body does not tip over.

The floating fulcrum P1f of the front lifting operation also moves according to the direction of the upper swivel body 3 and the state of the ground, similarly to the floating fulcrum P1r, and the distances D1 and D3 also change accordingly.

Therefore, in the present embodiment, the distance calculation unit 303 calculates the distances D1 to D4 according to the positions of the floating fulcrums P1f and P1r. The positions of the floating fulcrums P1f and P1r can be calculated by the floating fulcrum estimation unit 302 by using the relative turning angle θ of the upper turning body 3 with respect to the lower traveling body 1.

Here, the sensors mounted on the conventional excavator 100 basically do not have a means for detecting the relative turning angle θ of the upper turning body 3 with respect to the lower traveling body 1. On the other hand, in the present embodiment, the turning angle θ of the upper turning body 3 is calculated by using the acceleration AC of the upper turning body 3 while the lower running body 1 is running.

As shown in FIGS. 8A to 8C, when the lower traveling body 1 travels in a state where the turning angle θ of the upper rotating body 3 is different, the acceleration detection unit 31 mounted on the upper rotating body 3 travels in the lower part. The acceleration AC in the same direction as the traveling direction of the body 1 (upward in FIG. 8) is detected. The angle formed by the direction of the acceleration AC and the direction in which the attachment extends corresponds to the turning angle θ of the upper swing body 3. Therefore, if the acceleration detection unit 31 detects the acceleration AC of the upper turning body 3 while the lower traveling body 1 is traveling, the turning angle calculation unit 301 turns based on the direction of the acceleration AC detected by the acceleration detection unit 31. The angle θ can be calculated.

The calculation of the turning angle θ based on the direction of the acceleration AC will be specifically described. It suffices if the acceleration detection unit 31 can acquire at least the accelerations of the x-axis and the y-axis orthogonal to each other. For example, as shown in FIG. 8, the acceleration detection unit 31 is installed so that the x-axis faces the front-rear direction of the upper swivel body 3 and the y-axis faces the left-right width direction of the upper swivel body 3. In this case, since the acceleration detection unit 31 detects the acceleration only in the x direction when the turning angle θ = 0 ° shown in FIG. 8A, the relative turning angle θ of the upper turning body 3 with respect to the lower traveling body 1 is approximately the same. It turns out to be 0 °. Similarly, when the turning angle θ = 90 ° shown in FIG. 8C, the acceleration detection unit 31 detects the acceleration only in the y direction, so that the relative turning angle θ of the upper turning body 3 with respect to the lower traveling body 1 is approximately the same. It turns out to be 90 °.

On the other hand, as shown in FIG. 8B, when the turning angle θ is larger than 0 ° and smaller than 90 °, the acceleration detection unit 31 has both the acceleration component ACx in the x direction and the acceleration component ACy in the y direction. Is detected. From the magnitudes of these acceleration components ACx and ACy, it can be seen how much the turning angle θ is taken by the acceleration detection unit 31 (that is, the upper turning body 3) with respect to the running direction of the lower running body 1.

As for the reference direction of the turning angle θ, for example, the crawler of the upper turning body 3 and the lower traveling body 1 are calibrated in a facing state (for example, the position of FIG. 8A), and the acceleration AC at this time is performed. May be used as a reference, or a direction preset by the acceleration detection unit 31 may be used as a reference. The acceleration detection unit 31 may detect at least biaxial acceleration, but may use an IMU sensor or the like that can detect triaxial acceleration.

The determination unit 304 dynamically sets stability conditions (inequality (4), (8)) based on the information of the distances D1 to D4 calculated by the distance calculation unit 303, and uses the stability conditions of the lower traveling body 1. Identify the moment when the front or back rises. Further, the upper limit value setting unit 305 is the upper limit of the force F1 generated by the boom cylinder 7 so that the stability condition dynamically set by the determination unit 304 is satisfied, that is, the lower traveling body 1 is suppressed from floating. Set the value F1max.

The moment of lifting can be approximated to a state in which the moment τ1 based on the force F1 that the attachment tries to tilt the vehicle body and the moment τ2 based on the gravity against it are balanced. Therefore, by specifying the moment of lifting and monitoring the state of the excavator 100, the control conditions for suppressing the lifting can be adaptively set, and the lifting can be appropriately suppressed under various usage conditions.

The same values can be used for the distances D1 and D2 once acquired as long as the direction of the upper swivel body 3 does not change and the ground condition does not change. On the other hand, the distances D3 and D4 change according to the raising and lowering of the boom 4. When the angle of the boom 4 changes, the upper limit value setting unit 305 can change the distances D3 and D4 accordingly and reflect them in the control conditions.

FIG. 9 is a flowchart showing an example of suppression control of the floating operation. The processing of the flowchart shown in FIG. 9 can be periodically executed by the controller 30 during the operation of the excavator 100. Note that steps S01 to S03 in FIG. 9 correspond to steps S1 to S3 in the flowchart of FIG. Further, steps S06 to S09 in FIG. 9 are contents in which steps S4 to S7 in FIG. 3 are limited to the floating operation.

In step S01, the controller 30 determines whether or not the lower traveling body 1 of the excavator 100 is traveling. If the excavator 100 is running (Yes in step S01), the process proceeds to step S02, and if the shovel 100 is not running (No in step S01), the process proceeds to step S05.

In step S02, since the lower traveling body 1 is traveling, the acceleration detection unit 31 detects the acceleration AC of the upper rotating body 3 while the lower traveling body 1 is traveling. When the process of step S02 is completed, the process proceeds to step S03.

In step S03, the turning angle calculation unit 301 calculates the relative turning angle θ of the upper turning body 3 with respect to the lower traveling body 1 based on the direction of the acceleration AC detected by the acceleration detection unit 31 in step S02. .. As described with reference to FIG. 8, the turning angle calculation unit 301 can calculate, for example, the angle formed by the direction of the acceleration AC and the direction in which the attachment extends as the turning angle θ of the upper turning body 3. When the process of step S03 is completed, the process proceeds to step S04.

In step S04, the lift fulcrum P1f and the rear lift operation in the case of the front lift operation are based on the turn angle θ of the upper swing body 3 calculated by the lift fulcrum estimation unit 302 and the turn angle calculation unit 301 in step S03. The position of the floating fulcrum P1r in the case of is estimated. When the process of step S04 is completed, the process proceeds to step S05.

In step S05, the vehicle weight center P3 of the excavator 100 and the floating fulcrum P1 of the lower traveling body 1 are set based on the positions of the floating fulcrums P1f and P1r estimated by the distance calculation unit 303 and the floating fulcrum estimation unit 302 in step S04. The distances D1 and D2 between them are calculated. Further, in step S05, the distance calculation unit 303 also calculates the distances D3 and D4 between the extension line l2 of the boom cylinder 7 and the floating fulcrum P1. The distances D3 and D4 are geometrically determined based on the positions of the floating fulcrums P1f and P1r and the angle of the boom cylinder 7 (for example, the angle η1 formed by the boom cylinder 7 and the vertical shaft 130c shown in FIGS. 6 and 7). Can be calculated. The angle η1 can be calculated geometrically from the expansion and contraction length of the boom cylinder 7, the dimensional specifications of the excavator 100, the inclination of the vehicle body of the excavator 100, and the like. For example, the distance calculation unit 303 may calculate the angle η1 by using the output of the sensor that detects the boom angle that can be included in the various sensors 32, or directly obtains the angle η1 that can be included in the various sensors 32. It may be acquired by using the output of the sensor to be measured. When the process of step S05 is completed, the controller 30 stores the calculated information of the distances D1 to D4 and ends the control flow.

In step S06, since it is determined in step S01 that the lower traveling body 1 is not traveling, it is determined whether or not the excavator 100 is in the excavation work. If the excavator 100 is excavating (Yes in step S06), the process proceeds to step S06, and if not (No in step S06), the control flow is terminated.

In step S07, since it was determined in step S06 that the excavation work was in progress, the determination unit 304 determines whether or not the lower traveling body 1 is floating during the excavation work. For example, the determination unit 304 substitutes the information of the distances D1 to D4 calculated in step S05 and the information of the current force F1 of the boom cylinder 7 into the inequality (4) and (8) of the stability condition. The force F1 can be calculated, for example, based on the rod pressure PR and the bottom pressure PB of the boom cylinder 7. At this time, the determination unit 304 may acquire the rod pressure PR and the bottom pressure PB based on the output signals of the pressure sensor that detects the rod pressure and the bottom pressure of the boom cylinder 7 that may be included in the various sensors 32.

If at least one of the inequalities (4) and (8) is not satisfied as a result of the determination in step S07, it is determined that the stability condition of the excavator 100 is not satisfied and the floating operation is occurring (step S07). Yes), proceed to step S08. On the other hand, when both the inequalities (4) and (8) are satisfied, it is determined that the floating operation has not occurred because the stability condition of the excavator 100 is satisfied (No in step S07), and this control is performed. End the flow.

During the determination of the lifting operation of the lower traveling body 1 in step S07, the upper limit value setting unit 305 sets the upper limit value F1max of the force generated by the boom cylinder 7 within the range in which the lower traveling body 1 does not lift. For example, the upper limit value setting unit 305 substitutes the distances D1 to D4 calculated by the distance calculation unit 303 in step S05 into the inequalities (4) and (8), and sets the maximum value F1max so that the inequality is established. do.

In step S08, since it was determined in step S07 that the lower traveling body 1 has lifted up, the motion correction unit 306 corrects the motion of the boom cylinder 7. Specifically, the force F1 of the boom cylinder 7 (actuator) is controlled so that the upper limit value F1max set by the upper limit value setting unit 305 is not exceeded, and the operation of the attachment is corrected. The operation correction unit 306 performs, for example, a control to relieve when the force F1 of the boom cylinder 7 exceeds the upper limit value F1max, a control to reduce the supply flow rate and the discharge flow rate to the boom cylinder 7, and the like to reduce the supply flow rate and the discharge flow rate of the boom cylinder 7. The force F1 can be maintained below the upper limit value F1max. This correction suppresses the floating motion. When the process of step S09 is completed, the process proceeds to step S10.

In step S09, the controller 30 notifies the operator of the occurrence of the floating operation via the display device 33. The means for notifying the operator is not limited to the characters and visual information provided by the display device 33, and other means such as sound, voice, and vibration may be used. When the process of step S10 is completed, this control flow ends.

In addition, only one of the operation correction process of steps S08 to S09 and the notification process of step S10, which are performed after the floating operation occurs, may be performed.

Next, the action and effect of the excavator 100 of the present embodiment will be described. The shovel 100 of the present embodiment includes a lower traveling body 1, an upper rotating body 3 that is rotatably mounted on the lower traveling body 1, and an attachment (boom 4, arm 5, bucket 6) mounted on the upper rotating body 3. And the actuator (boom cylinder 7, arm cylinder 8, bucket cylinder 9) that drives the attachment, and the acceleration detection that is attached to the upper swivel body 3 and detects the acceleration AC of the upper swivel body 3 while the lower traveling body 1 is running. A unit 31 and a turning angle calculation unit 301 for calculating the relative turning angle θ of the upper turning body 3 with respect to the lower traveling body 1 based on the direction of the acceleration AC detected by the acceleration detecting unit 31.

Conventionally, since the excavator 100 has a difference in the length and width of the crawler of the lower traveling body 1 in the front-rear direction, the stability depends on which direction the upper turning body 3 on which the attachment is mounted faces the lower traveling body 1. Is very different. However, the conventional excavator is basically not equipped with a function of detecting the turning angle θ of the upper turning body 3 with respect to the lower traveling body 1. For this reason, the accuracy of determining the occurrence of unintended movement of the lower traveling body 1 including the lifting motion of the lower traveling body 1 may be lowered, and such movement may not be appropriately suppressed.

On the other hand, in the present embodiment, according to the above configuration, the relative turning angle θ of the upper turning body 3 with respect to the lower traveling body 1 can be calculated accurately based on the direction of the acceleration AC of the upper turning body 3. By using the calculated turning angle θ, it is possible to accurately determine the unintended movement of the lower traveling body 1 including the floating motion, which fluctuates according to the turning angle θ. Since the unintended movement of the lower traveling body 1 of the excavator 100 can be accurately determined, such an operation suppression process can be performed at an appropriate opportunity, and as a result, the unintended movement of the lower traveling body 1 can be performed satisfactorily. Can be suppressed.

Further, the shovel 100 of the present embodiment has a floating fulcrum estimation unit 302 that estimates the floating fulcrum points P1f and P1r when the floating operation of the lower traveling body 1 occurs based on the turning angle θ calculated by the turning angle calculation unit 301. Based on the information of the floating fulcrum points P1f and P1r estimated by the floating fulcrum estimation unit 302 and the force F1 generated by the actuator, the determination unit 304 for determining whether or not the floating operation of the lower traveling body 1 occurs. To prepare for.

With this configuration, it is possible to accurately estimate the floating fulcrums P1f and P1r of the lower traveling body 1 of the excavator 100 that fluctuates according to the turning angle θ by using the turning angle θ accurately calculated by the turning angle calculation unit 301. It is possible to accurately determine the occurrence of the lifting motion of the lower traveling body 1 during the excavation work by using the lifting fulcrums P1f and P1r estimated in. Since the floating motion can be determined with high accuracy, the floating motion can be suppressed at an appropriate opportunity, and as a result, the floating motion can be satisfactorily suppressed.

Further, the excavator 100 of the present embodiment has an upper limit value for setting an upper limit value F1max of the force generated by the actuator within a range in which the lower traveling body 1 does not rise, based on the floating fulcrum points P1f and P1r estimated by the floating fulcrum estimation unit 302. A setting unit 305 is provided. The upper limit value setting unit 305 sets the upper limit value F1max when it is determined by the determination unit 304 that the floating operation occurs.

With this configuration, since the upper limit value F1max of the actuator force is quickly set when the lifting operation occurs, the excavation work can be performed with the maximum force within the range where the lower traveling body 1 does not lift, and the work efficiency can be maintained.

Further, in the shovel 100 of the present embodiment, the upper limit value setting unit 305 sets the upper limit value F1max when the determination unit 304 determines that the floating operation occurs. That is, the actuator can be controlled without setting an upper limit on the force generated by the actuator when the floating motion does not occur, and the upper limit value F1max of the force is immediately set when the lifting motion occurs. As a result, the restrictions on the operation can be minimized when the floating operation does not occur, and the floating operation can be quickly suppressed when the floating operation occurs.

Further, the excavator 100 of the present embodiment includes a display device 33 that notifies the operator of the occurrence of the floating operation when the determination unit 304 determines that the floating operation occurs. As a result, the operator can quickly grasp the occurrence of the floating motion, so that the operator himself can avoid the floating motion by his own operation, and the lifting motion can be suppressed more reliably.

The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. These specific examples with appropriate design changes by those skilled in the art are also included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element included in each of the above-mentioned specific examples, its arrangement, conditions, a shape, and the like are not limited to those exemplified, and can be appropriately changed. The combinations of the elements included in each of the above-mentioned specific examples can be appropriately changed as long as there is no technical contradiction.

In the above embodiment, the upper limit value setting unit 305 illustrates a configuration in which the upper limit value F1max is set when the determination unit 304 determines that the floating operation occurs, but the upper limit value is set before the occurrence of the floating operation is detected. The setting unit 305 may set the upper limit value in advance and control the force F1 of the actuator so that the controller 30 does not exceed the upper limit value F1max. As a result, it is possible to suppress the occurrence of the floating operation in advance.

In the above embodiment, the configuration in which the acceleration detection unit 31 is attached to the upper swing body 3 is exemplified, but the acceleration detection unit 31 may be attached to an attachment (any of the boom 4, arm 5, and bucket 6).

In the above embodiment, the floating operation is exemplified as the operation of the excavator 100 that is not intended by the operator, and the control that suppresses the force of the boom cylinder to suppress the floating operation is exemplified as the stabilization control, but the unintended operation and the stabilization control are exemplified. May be other content. For example, as an unintended operation, a vibration operation generated in the excavator body during the aerial operation of the attachment of the excavator 100 may be included.

An example of the vibration operation of the excavator 100 will be described with reference to FIGS. 10 and 11. FIG. 10 is a diagram illustrating a situation in which a vibration operation occurs during the aerial operation of the excavator 100. Further, FIG. 11 is a diagram showing a time waveform of an angle (pitch angle) and an angular velocity (pitch angular velocity) in the pitching axis direction accompanying the ejection operation of the shovel 100 in the situation shown in FIG. In this example, as an example of the aerial operation, the discharge operation of discharging the load DP in the bucket 6 will be described.

As shown in FIG. 10A, the excavator 100 is in a state where the bucket 6 and the arm 5 are closed and the boom 4 is raised, and the bucket 6 accommodates a load DP such as earth and sand. ing.

As shown in FIG. 10B, when the excavator 100 is discharged from the state shown in FIG. 10A, the bucket 6 and the arm 5 are wide open, the boom 4 is lowered, and the load DP is bucketed. It is discharged to the outside of 6. At this time, the change in the moment of inertia of the attachment acts to vibrate the vehicle body of the shovel 100 in the pitching direction indicated by the arrow A in the figure.

At this time, as shown in FIG. 11, it can be seen that an overturning moment that tries to overturn the shovel 100 is generated due to the aerial operation, specifically, the discharging operation, and vibration around the pitch axis is generated. ..

Further, when the unintended operation is a vibration operation, the stabilization control is a suppression control of the vibration operation. This control has the following contents, for example. As described above, during the discharging operation that causes the vibration operation, an overturning moment due to the discharging operation is generated, and this overturning moment is transmitted to the shovel main body to generate the vibration operation.

The excavator 100 changes the ease of tipping due to this tipping moment according to the turning angle θ of the upper swinging body 3. As shown in FIG. 8A, when the turning angle θ is 0 degrees, the distance D2 between the center of gravity of the excavator and the floating fulcrum of the lower traveling body 1 becomes maximum, so that the excavator 100 falls over. Hateful. On the other hand, as shown in FIG. 8C, when the turning angle θ is 90 degrees, the distance D2 between the center of gravity of the excavator and the floating fulcrum of the lower traveling body 1 is the minimum, so that the excavator 100 has the minimum. Easy to fall.

In order to suppress vibration, basically, an upper limit value of the force of the boom cylinder 7 is set, and when a force higher than that is applied, the boom cylinder 7 is relieved and the overturning moment is absorbed by the boom cylinder 7. The closer the turning angle θ is to 90 degrees, the more likely it is that pitching will occur. To. Specifically, for example, the upper limit of the force of the boom cylinder 7 is lowered to facilitate relief.

On the other hand, the closer the turning angle θ is to 0 degrees, the less likely it is that pitching will occur. Therefore, it is difficult to relieve the boom cylinder 7 so that the upper limit of the force of the boom cylinder 7 is not lowered unnecessarily.

Further, as the stabilization control, the stability of the excavator 100 may be presented to the operator via the display device 33 by using the turning angle θ of the upper swing body 3 obtained in the above embodiment.

FIG. 12 is a diagram showing an example of the stability display of the display device 33. In the example of FIG. 12, the posture of the attachment, more specifically the position of the bucket, is a parameter, and the relationship between it and the predicted stability is visually shown. In this example, the predicted stability is represented by three values and is divided into areas for each value. The first region (i) indicates a safe region, the second region (ii) indicates a region requiring attention, and the third region (iii) indicates an unstable region.

The display of each area (i) to (iii) can be associated with the operation of the attachment. That is, the first region (i) can be grasped as an region where there is no problem even if the attachment is moved at high speed, in other words, an region where the attachment can be operated without any restriction. The second region (ii) is an region in which the speed (or power) of the attachment 12 should be reduced to operate at a low speed to a medium speed, and the third region (iii) is an region in which the attachment should be operated at a low speed (low power). ..

From another point of view, the stability display in FIG. 12 distinguishes between the area (i) in which the attachment can be operated without restriction and the areas (ii) and (iii) in which the operation of the attachment should be restricted. It can be said that.

From yet another point of view, the stability display in FIG. 12 can be said to visually indicate the predicted stability of the shovel with two parameters: the position of the bucket and the speed (or power) of the attachment.

The turning angle θ of the upper swing body 3 is different between FIGS. 12 (a) and 12 (b). In FIG. 12A, the turning angle θ = 0 degrees, and in FIG. 12B, the turning angle θ = 90 degrees. In FIG. 12 (b), the width of the lower traveling body 1 is narrower than that in the case of FIG. 12 (a), so it can be said that the vehicle is likely to fall. Therefore, the first region (i) in FIG. 12 (b) is narrower than that in FIG. 12 (a).

According to the example of FIG. 12, in the current state of the excavator, the operator can confirm how far the bucket can be moved without any problem before the operation. Alternatively, the operator can confirm before operation how much speed or power the bucket can be moved without any problem.

FIG. 13 is a diagram showing another example of the stability display of the display device 33. In the example of FIG. 13, the stability is displayed in a format superimposed on the windshield. For example, a display panel (display device 33) for displaying the boundary lines A and B may be embedded in the windshield so that the actual field of view seen beyond the windshield and the boundary lines A and B are superimposed. For example, a safe area (first area in FIG. 12) is in front of the boundary line A, a caution area (second area in FIG. 12) is between the boundary lines A and B, and an unstable area (an unstable area) is beyond the boundary line B. It may correspond to the third region) of FIG. By superimposing the display of the actual field of view and the predicted stability, the operator can more intuitively grasp the operation that may cause a fall or shaking.

Further, in the above embodiment, the configuration in which the turning angle θ of the upper swivel body 3 is calculated while the shovel is running and the unstable state during the subsequent attachment operation is determined based on the swiveling angle θ has been exemplified. Not limited to this. For example, it may be used for determining the unstable state in consideration of the turning amount after the running is completed. This control will be described with reference to FIG. FIG. 14 is a flowchart showing another example of suppression control of the floating operation.

Since steps S101 to S102 and S107 to S110 in FIG. 14 are the same processes as steps S01 to S02 and S06 to 09 in FIG. 9, description thereof will be omitted.

In step S103, the turning angle calculation unit 301 calculates the relative turning angle θ ₀ of the upper turning body 3 with respect to the lower traveling body 1 based on the direction of the acceleration AC detected by the acceleration detection unit 31 in step S102. To. This turning angle θ ₀ is a turning angle at the end of traveling of the excavator, and is a reference value of the current turning angle obtained in steps S105 and S106 described later.

In step S104, since it is determined in step S101 that the lower traveling body 1 is not traveling, it is determined whether or not the excavator is turning. For example, it is possible to detect whether or not the operator is performing a turning operation via the operating device 26 and determine whether or not the shovel is turning.

As a result of the determination in step S104, if the excavator is turning (Yes in step S104), the process proceeds to step S105, and the turning amount is added to the reference value θ ₀ of the turning angle calculated in step S103. The current turning angle θ of the upper turning body 3 is calculated. In this configuration, for example, the excavator is provided with a turning amount detection unit that detects the turning amount of the upper turning body 3 with reference to the turning angle θ ₀ at the end of traveling.

On the other hand, if the excavator is not turning (No in step S104) as a result of the determination in step S104, the process proceeds to step S106, and the reference value θ ₀ of the turning angle calculated in step S103 is the upper swivel body 3. Is set as the current turning angle θ of. When the process of step S105 or step S106 is completed, the process proceeds to step S107.

In step S110, similarly to step S09 in FIG. 9, the controller 30 notifies the operator of the occurrence of the floating operation via the display device 33, but in addition to this, turning in step S105 or step S106. Based on the current turning angle θ of the upper turning body 3 calculated by the angle calculation unit 301, that is, the unstable state of the excavator is determined by taking into account the turning amount after the end of running, which is related to the current stability of the vehicle body. The information to be used may be notified to the operator.

FIG. 15 is a diagram illustrating an example of a calibration method of the acceleration detection unit. As shown in FIG. 15, it is also possible to calibrate the acceleration detection unit 31 by inputting a fine operation of the lower traveling body 1 and causing the acceleration detection unit 31 to slightly vibrate. The fine operation of the lower traveling body 1 may be manually performed by the operator or automatically performed by the controller 30.

100 Excavator 1 Lower traveling body 3 Upper swivel body 30 Controller 31 Acceleration detection unit 33 Display device (notification unit)
301 Turning angle calculation unit 302 Lifting fulcrum estimation unit 303 Distance calculation unit 304 Judgment unit 305 Upper limit value setting unit 306 Operation correction unit

Claims (9)

With the lower running body,
An upper swivel body that can be swiveled on the lower traveling body and
The attachment mounted on the upper swing body and
The actuator that drives the attachment and
An acceleration detection unit attached to the upper swivel body or the attachment and detecting the acceleration of the upper swivel body while the lower traveling body is traveling.
A turning angle calculation unit that calculates the relative turning angle of the upper turning body with respect to the lower traveling body based on the direction of the acceleration detected by the acceleration detecting unit.
Excavator equipped with. A floating fulcrum estimation unit that estimates a floating fulcrum when a floating operation of the lower traveling body occurs based on the turning angle calculated by the turning angle calculation unit.
Based on the information of the floating fulcrum estimated by the floating fulcrum estimation unit and the force generated by the actuator, a determination unit for determining whether or not the floating operation of the lower traveling body occurs, and a determination unit.
The excavator according to claim 1. A claim that includes an upper limit setting unit for setting an upper limit value of the force generated by the actuator or the cylinder pressure within a range in which the lower traveling body does not float based on the floating fulcrum estimated by the floating fulcrum estimation unit. Item 2 Excavator. The upper limit value setting unit sets the upper limit value when the determination unit determines that the floating operation occurs.
The excavator according to claim 3. The determination unit is provided with a notification unit for notifying the operator of the occurrence of the floating operation when the determination unit determines that the floating operation will occur.
The excavator according to any one of claims 2 to 4. The acceleration detection unit includes a gyro sensor, an acceleration sensor, or an IMU (Inertial Measurement Unit).
The excavator according to any one of claims 1 to 5. A swivel amount detection unit for detecting the swivel amount of the upper swivel body with reference to the swivel angle at the end of traveling calculated by the swivel angle calculation unit is provided.
The turning angle calculation unit calculates the current turning angle of the upper turning body by adding the turning amount detected by the turning amount detecting unit to the calculated turning angle at the end of traveling.
The excavator according to any one of claims 1 to 6. Based on the current turning angle calculated by the turning angle calculation unit, the operator is notified of information related to the current stability of the vehicle body.
The excavator according to claim 7. The acceleration detection unit is calibrated by inputting a fine operation of the lower traveling body to cause the acceleration detection unit to vibrate slightly.
The excavator according to any one of claims 1 to 8.

Images