KR102641389B1 - Working machine and control method of working machine - Google Patents

Abstract

Suppresses the occurrence of slippage caused by the turning of the rotating body. The working machine includes a traveling body, a rotating body rotatably mounted on the traveling body, and a controller that controls the operation of the working machine. The controller determines the occurrence of slippage of the traveling body during the swing movement of the swing body during automatic operation of the working machine. If the controller determines that slippage has occurred, it executes processing to reduce the rotational inertia force generated during the turning operation.

Description

Working machine and control method of working machine

This disclosure relates to a working machine and a control method of the working machine.

Regarding the excavator, in Japanese Patent Laid-Open No. 2019-7173 (Patent Document 1), it is an operation of the excavator that is not intended by the operator, and even though the operator is not operating the traveling body, the excavation reaction force causes the excavator to move. A forward dragging operation in which the excavator is pulled forward, and a rear dragging operation in which the excavator is pulled rearward by a reaction force from the ground in the leveling operation are exemplified.

Japanese Patent Publication No. 2019-7173

In the above document, it is stated that the operation of the excavator that is not intended by the operator is caused by the operation of the attachment, that is, the boom, arm, and bucket, and that the unintended operation can be suppressed by controlling the attachment. Specifically, it is described that the dragging motion of the excavator can be suppressed by correcting the operation of the boom cylinder, which is a hydraulic actuator that drives the boom.

In an excavator having a traveling body and a swing body mounted on the traveling body so as to be able to pivot, it is desirable in terms of work efficiency to suppress the occurrence of slippage of the traveling body when the swing body turns with respect to the traveling body. However, there is no description from this perspective in the above document.

In the present disclosure, a working machine and a control method of the working machine that can suppress the occurrence of slippage due to the turning of the rotating body are provided.

According to the present disclosure, a working machine is provided, which includes a traveling body, a swing body rotatably mounted on the traveling body, and a controller that controls the operation of the working machine. The controller determines the occurrence of slippage of the traveling body during the swing movement of the swing body during automatic operation of the working machine. If the controller determines that slippage has occurred, it executes processing to reduce the rotational inertia force generated during the turning operation.

According to the present disclosure, occurrence of slippage due to rotation of the rotating body can be suppressed.

[Figure 1] is an external view of a hydraulic excavator based on the embodiment.
[FIG. 2] A diagram schematically showing the system configuration of a hydraulic excavator based on the embodiment.
[Figure 3] A diagram showing a configuration for controlling the turning of a rotating body.
[FIG. 4] is a block diagram showing a partial electrical configuration of a hydraulic excavator based on the embodiment.
[Figure 5] is a block diagram showing the functional configuration of the controller.
[Figure 6] A schematic diagram showing the turning operation of a hydraulic excavator for topdressing with a dump truck.
[Figure 7] A schematic diagram showing the occurrence of slippage of the hydraulic excavator during turning deceleration.
[Figure 8] is a flow chart showing the processing flow when slippage occurs in the hydraulic excavator during turning deceleration.
[FIG. 9] A graph for explaining the first process for reducing the rotational inertia force generated during turning deceleration.
[FIG. 10] A schematic diagram for explaining the second process for reducing the rotational inertia force generated during turning deceleration.
[FIG. 11] A schematic diagram for explaining the third process for reducing the rotational inertia force generated during turning deceleration.
[Figure 12] A schematic diagram of a system including a hydraulic excavator.

Hereinafter, embodiments will be described with reference to the drawings. In the following description, the same parts are given the same symbols. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

1 is an external view of a hydraulic excavator 100 based on the embodiment. As shown in FIG. 1, as a working machine, in this example, the hydraulic excavator 100 is mainly used as an example.

The hydraulic excavator 100 includes a main body 1 and a work tool 2 operated by hydraulic pressure. The main body 1 is provided with a rotating body 3 and a traveling body 5. The traveling body 5 is provided with a pair of crawler belts 5Cr and a traveling motor 5M. The traveling motor 5M is installed as a driving source for the traveling body 5. The traveling motor 5M is a hydraulic motor that operates by hydraulic pressure.

When the hydraulic excavator 100 operates, the traveling body 5, more specifically, the crawler belt 5Cr is in contact with the ground. The traveling body 5 can travel on the ground by rotating the crawler belt 5Cr. Additionally, the traveling body 5 may have wheels (tires).

The rotating body 3 is disposed on the traveling body 5 and is supported by the traveling body 5. The swing body 3 is mounted on the traveling body 5 so as to be able to pivot with respect to the traveling body 5 about the swing axis RX. The pivot body 3 has a cab 4. The occupant (operator) of the hydraulic excavator 100 rides in this cab 4 and operates the hydraulic excavator 100. The cab 4 is provided with a driver's seat 4S where the operator sits. The operator can operate the hydraulic excavator 100 within the cab 4. The operator can operate the work machine 2 within the cab 4, and can operate the swing body 3 with respect to the traveling body 5, and can also operate the hydraulic excavator ( 100) driving operations are possible.

The rotating body 3 is provided with an engine room 9 in which the engine is accommodated, and a counterweight installed at the rear of the rotating body 3. In the engine room 9, an engine 31 and a hydraulic pump 33, which will be described later, are arranged.

In the swing body 3, a handrail 19 is provided in front of the engine room 9. An antenna 21 is installed on the handrail 19. The antenna 21 is, for example, an antenna for GNSS (Global Navigation Satellite Systems). The antenna 21 has a first antenna 21B and a second antenna 21B installed on the rotating body 3 so as to be spaced apart from each other in the vehicle width direction.

The work machine 2 is mounted on the rotating body 3 and is supported on the rotating body 3. The work machine 2 has a boom 6, an arm 7, and a bucket 8. The boom (6) is rotatably connected to the pivot body (3). The arm (7) is rotatably connected to the boom (6). The bucket (8) is rotatably connected to the arm (7). The bucket 8 has multiple blades. The tip of the bucket 8 is called a cutting edge 8a.

Also, the bucket 8 does not need to have a blade. The tip of the bucket 8 may be formed of a straight steel plate.

The proximal end of the boom 6 is connected to the pivot body 3 via a boom pin 13. The proximal end of the arm 7 is connected to the distal end of the boom 6 via the arm pin 14. The bucket 8 is connected to the distal end of the arm 7 through a bucket pin 15.

In this embodiment, the positional relationship of each part of the hydraulic excavator 100 will be described based on the work machine 2.

The boom 6 of the work machine 2 rotates with respect to the swing body 3 around the boom pin 13 installed at the base end of the boom 6. The trajectory along which a specific part of the boom 6 rotating with respect to the rotating body 3, for example, the tip of the boom 6, moves is in the shape of an arc, and the plane containing the arc is specified. When the hydraulic excavator 100 is viewed from a plane, the plane is expressed as a straight line. The direction in which this straight line extends is the front-back direction of the main body 1 of the hydraulic excavator 100, or the front-back direction of the swing body 3, and is hereinafter referred to simply as the front-back direction. The left-right direction (vehicle width direction) of the main body 1 of the hydraulic excavator 100, or the left-right direction of the swing body 3, is a direction perpendicular to the front-back direction in plan view, and is hereinafter referred to simply as the left-right direction. The vertical direction of the vehicle body or the vertical direction of the swing body 3 is a direction perpendicular to a plane defined by the front-back direction and the left-right direction, and is hereinafter referred to simply as the vertical direction.

In the front-back direction, the side on which the work tool 2 protrudes from the main body 1 of the hydraulic excavator 100 is the front direction, and the direction opposite to the front direction is the rear direction. When looking in all directions, the right and left sides of the left and right directions are the right and left directions, respectively. In the vertical direction, the side with the ground is the lower side, and the empty side is the upper side.

The anteroposterior direction is the anteroposterior direction of the operator seated on the driver's seat 4S in the cab 4. The direction facing the operator seated in the driver's seat 4S is the forward direction, and the direction behind the operator seated in the driver's seat 4S is the rear direction. The left and right direction is the left and right direction of the operator seated in the driver's seat 4S. When the operator sitting in the driver's seat (4S) faces the front, the right and left sides are the right and left directions, respectively. The vertical direction is the vertical direction of the operator seated in the driver's seat 4S. The side under the feet of the operator seated in the driver's seat 4S is the lower side, and the side above the head is the upper side. .

The boom (6) can rotate around the boom pin (13). The arm (7) can rotate around the arm pin (14). The bucket (8) is rotatable about the bucket pin (15). Each of the arm 7 and the bucket 8 is a movable member that can move toward the front end of the boom 6. The boom pin 13, arm pin 14, and bucket pin 15 extend in the left and right directions.

The work machine 2 is equipped with a boom cylinder 10, an arm cylinder 11, and a bucket cylinder 12. Boom cylinder 10 drives boom 6. The arm cylinder 11 drives the arm 7. Bucket cylinder 12 drives bucket 8. Each of the boom cylinder 10, arm cylinder 11, and bucket cylinder 12 is a hydraulic cylinder driven by hydraulic oil.

The bucket cylinder (12) is mounted on the arm (7). As the bucket cylinder 12 expands and contracts, the bucket 8 rotates with respect to the arm 7. The work machine 2 is equipped with a bucket link. The bucket link connects the bucket cylinder (12) and the bucket (8).

A controller 26 is mounted on the hydraulic excavator 100. The controller 26 controls the operation of the hydraulic excavator 100. Details of the controller 26 will be described later.

FIG. 2 is a block diagram showing the system configuration of the hydraulic excavator 100 based on the embodiment. As shown in FIG. 2, the hydraulic excavator 100 includes a controller (main controller) 26, an engine 31, a hydraulic pump 33, a tank 35, and a main valve 40. , Equipped with a swing motor (3M).

The system shown in FIG. 2 is configured so that the hydraulic pump 33 is driven by the engine 31, and the hydraulic oil discharged from the hydraulic pump 33 is supplied to various hydraulic actuators through the main valve 40. By controlling the supply and discharge of hydraulic pressure to the hydraulic actuator, the operation of the work machine 2, the turning of the swing body 3, and the traveling operation of the traveling body 5 are controlled. The hydraulic actuator includes a boom cylinder 10, an arm cylinder 11, a bucket cylinder 12, a swing motor 3M, and a travel motor 5M shown in FIG. 1. The swing motor 3M is installed as a drive source for turning the swing body 3.

The engine 31 is, for example, a diesel engine. The engine controller 36 controls the operation of the engine 31. By controlling the injection amount of fuel into the engine 31 by the engine controller 36, the output of the engine 31 is controlled. The engine 31 has a drive shaft for connection to the hydraulic pump 33.

The hydraulic pump 33 supplies hydraulic oil used to drive the work machine 2 and rotate the swing body 3. The hydraulic pump 33 is connected to the drive shaft of the engine 31. The hydraulic pump 33 is driven by transmitting the rotational driving force of the engine 31 to the hydraulic pump 33. The hydraulic pump 33 is a variable displacement hydraulic pump that has a swash plate and changes the discharge capacity by changing the tilt angle of the swash plate.

The tank 35 is a tank that stores oil used by the hydraulic pump 33. The oil stored in the tank 35 is sucked out from the tank 35 by driving the hydraulic pump 33 and supplied to the main valve 40 via the hydraulic oil passage 42.

The main valve 40 is a spool-type valve that changes the direction in which hydraulic oil flows by moving a rod-shaped spool. The main valve 40 has respective spools that adjust the supply amount of hydraulic oil to each of the boom cylinder 10, arm cylinder 11, bucket cylinder 12, and swing motor 3M. By moving each spool in the axial direction, the supply amount of hydraulic oil to the hydraulic actuators, that is, the boom cylinder 10, arm cylinder 11, bucket cylinder 12, and swing motor 3M, is adjusted. Hydraulic oil is oil supplied to the hydraulic actuator in order to operate the hydraulic actuator.

A part of the oil delivered from the hydraulic pump 33 branches off from the hydraulic oil passage 42 and flows into the pilot passage 50. A part of the oil delivered from the hydraulic pump 33 is depressurized by the self-pressure pressure reducing valve 52, and the depressurized oil is used as pilot oil. Pilot oil is oil supplied to the main valve 40 in order to operate the spool of the main valve 40.

An EPC valve (electromagnetic proportional control valve) 54 is installed in the pilot passage 50. Each EPC valve 54 is installed for each spool that adjusts the supply amount of hydraulic oil to the boom cylinder 10, arm cylinder 11, bucket cylinder 12, and swing motor 3M. The EPC valve 54 adjusts the hydraulic pressure of the pilot oil (pilot hydraulic pressure) based on the control signal (EPC current) from the controller 26. The EPC valve 54 is controlled based on a control signal from the controller 26.

The EPC valve 54 adjusts the pilot oil pressure of the pilot oil supplied to each of the pair of hydraulic chambers of the main valve 40, and adjusts the pilot oil pressure supplied to the hydraulic actuator via the main valve 40. Adjust the supply amount of hydraulic oil. The flow direction and flow rate of the hydraulic oil supplied to each hydraulic actuator are adjusted by the main valve 40, and the supply of the hydraulic oil to each hydraulic actuator is controlled, thereby controlling the output of each hydraulic actuator. As a result, the operation of the work machine 2 and the swing operation of the swing body 3 are controlled.

FIG. 3 is a diagram showing a configuration for controlling the rotation of the rotating body 3. The hydraulic oil passage 42 through which the hydraulic oil used for turning the swing body 3 relative to the traveling body 5 flows is the supply passage 43 through which the hydraulic oil supplied to the swing motor 3M flows, and the swing motor 3M ) has a discharge passage 44 through which hydraulic oil discharged from ) flows. A hydraulic pump 33 and a meter-in throttle 61 are installed in the supply passage 43. A meter out throttle 62 is installed in the discharge passage 44. The meter out throttle 62 can change the opening area. By changing the opening area of the meter out throttle 62, the flow rate of hydraulic oil flowing through the discharge passage 44 can be controlled.

The main valve 40 shown in FIG. 3 has a turning spool 41 that adjusts the supply amount of hydraulic oil to the turning motor 3M. The meter-in throttle (61) and meter-out throttle (62) are included in the swing spool (41).

A relief valve 66 is installed in a branch line branching from the discharge passage 44 between the swing motor 3M and the meter out throttle 62. The input port of the relief valve 66 is connected to the discharge passage 44, and the output port of the relief valve 66 is connected to the tank. When the pressure of the hydraulic oil flowing out of the swing motor 3M and flowing in the discharge passage 44 becomes more than the relief pressure, the relief valve 66 is opened, and a part of the hydraulic oil in the discharge passage 44 is released from the relief valve ( 66) and flows into the tank. Normally, the flow of hydraulic oil in the hydraulic oil passage 42 is controlled so that the pressure of the hydraulic oil in the discharge passage 44 is lower than the relief pressure.

The deceleration of turning of the turning body 3, that is, the amount of reduction in turning speed per unit time, is controlled using the meter-out throttle 62. The EPC valve (FIG. 2), which receives a control signal from the controller 26, adjusts the pilot hydraulic pressure by adjusting its opening degree. The turning spool 41 moves in the axial direction in accordance with the pilot hydraulic pressure. The meter out throttle 62 changes the opening area according to the amount of movement of the turning spool 41.

By reducing the opening area of the meter-out throttle 62, the pressure of the hydraulic oil in the discharge passage 44 on the meter-out side increases, and the resulting braking force increases. As a result, the deceleration of the rotating body 3 increases, and the rotating body 3 rapidly decelerates in a short period of time. By increasing the opening area of the meter-out throttle 62, the pressure of the hydraulic oil in the discharge passage 44 on the meter-out side decreases, and the resulting braking force decreases. As a result, the deceleration of the rotating body 3 becomes small, and the rotating body 3 decelerates gently.

FIG. 4 is a block diagram showing a partial electrical configuration of the hydraulic excavator 100 based on the embodiment. As shown in FIG. 4, the controller 26 has a memory 261. The memory 261 stores programs for controlling various operations of the hydraulic excavator 100. The controller 26 executes various processes to control the operation of the hydraulic excavator 100 based on the program stored in the memory 261. The memory 261 is a non-volatile memory and is installed as an area to store necessary data.

The antenna 21 outputs a signal according to the received radio wave (GNSS radio wave) to the global coordinate calculation unit 23. The global coordinate calculation unit 23 detects the installation position of the antenna 21 in the global coordinate system. The global coordinate system is a three-dimensional coordinate system based on the reference position set in the work area. The reference position may be the position of the tip of a reference marker set in the work area.

The IMU (Inertial Measurement Unit) 24 is installed on the orbital body 3. In this example, the IMU 24 is disposed below the cap 4. In the rotating body 3, a highly rigid frame is disposed at the lower part of the cab 4. An IMU 24 is disposed on the frame. Additionally, the IMU 24 may be disposed on the side (right or left) of the pivot RX of the pivot body 3. The IMU 24 measures the acceleration of the rotating body 3 in the front-back, left-right, and up-down directions, and the angular velocity of the rotating body 3 around the front-back, left-right, and up-down directions.

The man-machine interface unit 28 has an input unit 281 and a display unit (monitor) 282. The input unit 281 is operated by an operator. The input unit 281 has operation buttons arranged around the display unit 282. The input unit 281 may have a touch panel. The command signal generated by manipulating the input unit 281 is output to the controller 26. The display unit 282 displays basic information such as remaining fuel amount and coolant temperature, and operation information of the hydraulic excavator 100.

The controller 26 transmits a control signal to the EPC valve 54. The EPC valve 54 is controlled based on a control signal from the controller 26. The EPC valve 54 adjusts the opening degree based on the control signal input from the controller 26 and adjusts the pressure of the pilot oil supplied to each spool of the main valve 40. As each spool moves in the axial direction in accordance with the pilot hydraulic pressure, the supply amount of hydraulic oil to the hydraulic actuators, that is, the boom cylinder 10, arm cylinder 11, bucket cylinder 12, and swing motor 3M, is adjusted.

The EPC valve 54 corresponding to the turning spool 41 adjusts the opening degree based on the control signal input from the controller 26, so that the pilot hydraulic pressure supplied to the turning spool 41 is adjusted, and the turning spool 41 ) moves in the axial direction. In accordance with the movement amount of the turning spool 41, the meter out throttle 62 adjusts the opening area of the hydraulic oil passage 42 (discharge passage 44, FIG. 3) to adjust the pressure of the hydraulic oil in the discharge passage 44. Adjust.

The controller 26 transmits a control signal to the relief valve 66. The relief valve 66 is controlled based on a control signal from the controller 26. The controller 26 outputs a control signal indicating the set value of the relief pressure to the relief valve 66.

Figure 5 is a block diagram showing the functional configuration of the controller 26. As shown in FIG. 5, the controller 26 includes a turning body position acquisition unit 102, a turning deceleration setting unit 104, a target excavation amount setting unit 106, and a work machine attitude setting unit 108 when turning. ) is provided.

The orbiting body position acquisition unit 102 determines the antenna 21 from the detection result of the installation position of the antenna 21 in the global coordinate system detected by the global coordinate calculation unit 23 based on the GNSS radio wave received by the antenna 21. ) acquires the coordinates of the reference position of the rotating body (3) on which it is mounted. Typically, the pivot position acquisition unit 102 acquires the coordinates of the pivot axis RX. Additionally, the orbiting body position acquisition unit 102 acquires the angle of rotation of the orbiting body 3 with respect to the ground from the measurement result of the angular velocity by the IMU 24.

The turning deceleration setting unit 104 sets the turning deceleration of the turning object 3, that is, the amount of reduction in turning speed per unit time. The controller 26 generates a control signal corresponding to the turning deceleration set by the turning deceleration setting unit 104 and outputs the control signal to the EPC valve 54. By adjusting the pilot hydraulic pressure supplied to the turning spool 41 and moving the turning spool 41 in the axial direction, the opening area of the meter out throttle 62 is adjusted.

The target excavation amount setting unit 106 sets a target value of the excavation amount for excavating an object to be excavated, such as earth and sand, by the work machine 2. The target value of this excavation amount is hereinafter referred to as the target excavation amount. The target excavation amount setting unit 106 sets the target excavation amount of the excavation object. The controller 26 generates a control signal corresponding to the target excavation amount set by the target excavation amount setting unit 106, outputs the control signal to the EPC valve 54, and sends the target excavation amount to the bucket 8. The work machine 2 is controlled so that the excavation object is loaded.

The working machine attitude setting unit 108 when turning sets the relative position of the working machine 2 with respect to the turning body 3 when the turning body 3 performs a turning operation. The controller 26 generates a control signal corresponding to the posture of the work machine 2 set by the work machine posture setting unit 108 when turning, outputs the control signal to the EPC valve 54, and outputs the control signal to the EPC valve 54 to Control the work machine (2) so that (2) assumes the set posture.

FIG. 6 is a schematic diagram showing the turning operation of the hydraulic excavator 100 for topdressing into the dump truck 200. As shown by the curved arrow in Fig. 6(A), the swing body 3 rotates with respect to the traveling body 5 centered on the swing axis RX (Fig. 1). As shown in FIG. 6B, the turning body 3 stops turning at a position where it is in an attitude facing the work machine 2 on the platform 202 of the dump truck 200. At this position, the hydraulic excavator 100 dumps the load object, such as soil and sand, loaded in the bucket 8 onto the carrier 202 of the dump truck 200. The load object, such as soil and sand, loaded in the bucket 8 is an example of the load carried by the work machine 2 in the embodiment.

Fig. 7 is a schematic diagram showing the occurrence of slippage of the hydraulic excavator 100 during turning deceleration. In Fig. 7(A), the turning of the pivot body 3 with the pivot axis RX as the rotation center is shown, similar to Fig. 6(A). When the turning speed of the turning body 3 decreases, a rotational inertial force due to the moment of inertia of the turning turning body 3 acts on the traveling body 5. If this rotational inertia force is greater than the maximum static friction force of the crawler belt 5Cr with respect to the ground, slippage of the traveling body 5 with respect to the ground occurs. When the frictional resistance between the ground and the crawler belt 5Cr decreases, such as when the ground in contact with the crawler belt 5Cr is wet from rain, slippage of the traveling body 5 becomes likely to occur.

The ground surface G indicated by a broken line in FIG. 7B represents the ground with which the traveling body 5 is in contact with the turning body 3. As indicated by the white arrow in FIG. 7(B), when slippage of the traveling body 5 occurs, the crawler belt 5Cr moves in the turning direction of the swing body 3, and the crawler belt 5Cr It deviates from the ground plane (G). When slippage of the traveling body 5 with respect to the ground plane G occurs, the hydraulic excavator 100 as a whole moves with respect to the ground, and the relative position of the work machine 2 with respect to the dump truck 200 becomes misaligned. .

If the displacement of the hydraulic excavator 100 due to slipping becomes large enough to cause the work machine 2 to deviate from the carrier 202 of the dump truck 200 after the rotation of the swing body 3, the topdressing position on the dump truck 200 There is a possibility that load overflow may occur due to misalignment. When the swing body 3 is rotated in the reverse direction to prevent load overflow, the cycle time becomes longer. In this way, as slippage occurs, the efficiency of the excavation and loading work is reduced.

In the hydraulic excavator 100 of the embodiment, the sliding body 5 is prevented when the swing body 3 is turned during automatic operation in which the hydraulic excavator 100 automatically loads the dump truck 200. When a load is generated, the occurrence of slippage of the traveling body 5 when the swing body 3 next turns is suppressed. FIG. 8 is a flowchart showing the processing flow when slippage occurs in the hydraulic excavator 100 during turning deceleration.

As shown in Fig. 8, first, in step S1, excavation is performed. The controller 26 controls the operation of the work machine 2 and the swing body 3 by transmitting a control signal to the EPC valve 54. By moving the bucket 8 to an appropriate position for executing the excavation work and operating the work tool 2 appropriately at that position, the excavation object such as soil is excavated by the bucket 8, and the excavation object such as soil is excavated within the bucket 8. The excavation object is loaded.

In step S2, the rotating body 3 is rotated. The controller 26 controls the operation of the work machine 2 and the swing body 3 by transmitting a control signal to the EPC valve 54. While maintaining the relative position of the work machine 2 with respect to the swing body 3 with a load loaded in the bucket 8, or while raising or lowering the work machine 2, the swing body 3 is relative to the traveling body 5. ) is rotated by a predetermined angle. The controller 26 automatically sets the angle at which the swing body 3 turns based on the position at which the excavation work is performed and the position of the carrier 202 of the dump truck 200.

In step S3, the position of the swing body 3 after the swing body 3 stops turning is acquired. The controller 26, specifically the orbiting body position acquisition unit 102 (FIG. 5), rotates based on the GNSS radio waves received by the antenna 21 and/or the angular velocity measurement results by the IMU 24. The position of the rotating body 3 after the rotating body 3 has stopped is acquired.

In step S4, it is determined whether the traveling body 5 (crawler belt 5Cr) is slipping with respect to the ground. For example, the operation to make the traveling body 5 travel is not performed, and the signal for driving the traveling motor 5M (FIG. 1) is not transmitted to the EPC valve 54, so the traveling motor 5M is not transmitted. Even though it is stationary, when the position of the pivot axis RX changes before and after turning, the controller 26 determines that the traveling body 5 is slipping with respect to the ground.

Alternatively, the turning angle of the turning body 3 with respect to the traveling body 5 is detected by a turning angle sensor, the turning angle of the turning body 3 with respect to the ground is detected by the IMU 24, and the detected turning angle is When the difference is greater than or equal to a predetermined threshold value, the controller 26 determines that the traveling body 5 is slipping with respect to the ground. Alternatively, the turning target angle automatically set by the controller 26 based on the position at which the excavation work is performed and the position of the carrier 202 of the dump truck 200 and the turning angle of the turning body 3 with respect to the ground When the difference is greater than or equal to a predetermined threshold value, the controller 26 determines that the traveling body 5 is slipping with respect to the ground.

The turning angle of the rotating body 3 with respect to the ground can be detected by acquiring an image with a visual sensor mounted on the hydraulic excavator 100 and estimating the self-position and attitude of the hydraulic excavator 100 through scan matching. do. The turning angle of the rotating body 3 with respect to the ground may be detected from the difference between the azimuth angle of the GNSS before turning and the azimuth angle of the GNSS after turning.

If it is determined that the traveling body 5 is slipping with respect to the ground (YES in step S4), the process proceeds to step S5 and it is determined whether the number of times it is determined that slipping has occurred is less than the threshold. The controller 26 reads the threshold values of the number of times it is determined that slippage has occurred and the number of times it has been determined that slippage has occurred before the judgment in the immediately preceding step S4 that are stored in the memory 261. The controller 26 adds 1 to the number of times it is determined that slippage has occurred before the judgment in the immediately preceding step S4, compares the number of times after the addition with the threshold, and determines whether the number of times after the addition is less than the threshold. .

If it is determined that the number of times after addition is less than the threshold value (YES in step S5), the process proceeds to step S6, and the controller 26 next reduces the turning speed of the swing body 3 with respect to the traveling body 5. Executes processing to reduce the rotational inertia force that occurs when

Fig. 9 is a graph for explaining the first process for reducing the rotational inertia force generated during turning deceleration. Figure 9 shows a graph showing the change in turning speed over time when slippage occurs and when turning. The horizontal axis of the graph represents time, and the vertical axis of the graph represents turning speed.

When slippage occurs, it is assumed that the turning speed ω is maintained from time 0 to time T1, deceleration begins at time T1, and the turning speed decelerates to 0 at time T2. In this case, during the next turn, if the turning speed ω is the same at time 0, the time to start deceleration is set to decelerate from the same time T2 to turning speed 0 and turn the turning body 3 by the turning target angle. , Set to time T0 before time T1.

When the turning speed decreases in the next turn after it is determined that slippage has occurred, the timing of starting turning deceleration is advanced, so that the amount of decrease in turning speed per unit time is smaller than when slippage occurs. By reducing the deceleration during turning, the rotational inertial force is reduced. By gently decelerating the rotating body 3, the occurrence of slippage is suppressed. By making the rotational inertia force smaller than the maximum static friction force of the crawler belt 5Cr with respect to the ground, slippage can be prevented.

The amount of reduction in the turning speed can be controlled using the meter out throttle 62 of the turning spool 41 in the main valve 40 shown in FIG. 3. The pressure of the hydraulic oil in the discharge passage 44 between the swing motor 3M and the meter out throttle 62 is controlled in front of the relief pressure of the relief valve 66. When the pressure of the hydraulic oil in the discharge passage 44 on the downstream side of the swing motor 3M is high, the resistance to rotation of the swing motor 3M increases, and it acts as a brake to stop the rotation of the swing motor 3M.

By controlling the opening degree of the EPC valve 54 by the controller 26, the pilot hydraulic pressure supplied to the swing spool 41 is adjusted and the opening area of the meter out throttle 62 is changed. By controlling the meter out throttle 62 in the opening direction, resistance to the flow of hydraulic oil passing through the meter out throttle 62 is reduced. The pressure of the hydraulic oil in the discharge passage 44 between the swing motor 3M and the meter out throttle 62 is lowered.

By lowering the pressure of the hydraulic oil in the discharge passage 44 on the downstream side of the swing motor 3M, the braking force acting on the swing motor 3M can be reduced, and the amount of decrease in the turning speed can be reduced. Therefore, by opening the meter out throttle 62, the amount of decrease in turning speed per unit time can be reduced.

Alternatively, the amount of reduction in turning speed can be controlled using the relief valve 66 shown in FIG. 3. If the setting value of the relief pressure of the relief valve 66 is set high, the deceleration of turning increases. If the setting value of the relief pressure of the relief valve 66 is set low, the deceleration of turning becomes small. Therefore, when slippage of the traveling body 5 occurs, the set value of the relief pressure when the turning speed of the swinging body 3 with respect to the traveling body 5 decreases may be controlled to be lowered.

Fig. 10 is a schematic diagram for explaining the second process for reducing the rotational inertia force generated during turning deceleration. FIG. 10 shows a bucket 8 and a load carried by the bucket 8, typically an excavation object such as soil loaded into the bucket 8 during an excavation operation.

When slippage occurs, it is assumed that a load of load P1 is loaded in the bucket 8, and the amount of load carried by the work machine 2 is load P1. In this case, the target excavation amount setting unit 106 sets and changes the next target excavation amount to an amount smaller than the current target excavation amount. The amount of load carried by the work machine 2 is set to the load amount P2, which is smaller than the load amount P1. By reducing the amount of load carried by the work machine 2, the rotational inertia force when the turning speed decreases is reduced. As a result, the occurrence of slippage is suppressed. By making the rotational inertia force smaller than the maximum static friction force of the crawler belt 5Cr with respect to the ground, slippage can be prevented.

Fig. 11 is a schematic diagram for explaining the third process for reducing the rotational inertia force generated during turning deceleration. FIG. 11 shows a schematic diagram of the hydraulic excavator 100 viewed from the left. The turning body 3 is mounted on the traveling body 5 so as to be able to turn around the turning axis RX. The work machine 2 is mounted on the rotating body 3 so that it can move relative to the rotating body 3. The bucket 8 is loaded with cargo P.

Compared to the attitude of the work machine 2 when slippage occurs, during the next turn, the work machine 2 is closer to the pivot axis RX around which the turn of the swing body 3 is centered. The distance from the pivot axis (RX) to the work machine (2), with the work machine (2) in a folded position when the swing body (3) is turned, typically a bucket for loading cargo (P) from the pivot shaft (RX). By reducing the distance to (8), the rotational inertial force when the turning speed decreases is reduced. As a result, the occurrence of slippage is suppressed. By making the rotational inertia force smaller than the maximum static friction force of the crawler belt 5Cr with respect to the ground, slippage can be prevented.

In this way, when slippage of the traveling body 5 with respect to the ground (ground surface G, FIG. 7) occurs, the rotational inertia force generated when the turning speed of the swing body 3 next decreases is reduced. By doing so, it is possible to suppress the occurrence of slipping due to the rotation of the rotating body 3. Then, the processing ends (“End” in FIG. 8).

In the judgment in step S5 of Fig. 8, if it is determined that the number of times slippage has been determined to be more than the threshold (NO in step S5), the process proceeds to step S7 and the automatic operation is stopped. The phenomenon of slipping of the traveling body 5 is repeated even during the next turn after performing the process of reducing the rotational inertia force in step S6, and when this phenomenon reaches the threshold number of times, the controller 26 ) stops the automatic operation of the hydraulic excavator (100). In order to avoid problems such as the target work efficiency not being achieved or the posture of the hydraulic excavator 100 becoming unstable due to repeated slippage, the automatic operation of the hydraulic excavator 100 is stopped. Then, the processing ends (“End” in FIG. 8).

The threshold value of the number of times slippage is determined to have occurred is set to an integer of 1 or more. This threshold may be stored in advance in memory 261. The threshold setting value may be input to the controller 26 by the operator manipulating the input unit 281 of the man-machine interface unit 28 (FIG. 4).

In the judgment in step S4, if it is determined that the traveling body 5 is not sliding with respect to the ground (NO in step S4), processing to reduce the rotational inertia force is not performed, and processing to stop automatic operation is also performed. Instead, the processing ends as is (“End” in FIG. 8).

When processing to reduce the rotational inertia force is performed in step S6 and processing to stop automatic operation is performed in step S7, the controller 26 may notify the operator that this processing has been performed. Additionally, the operator may be notified that slipping has occurred during the turning of the rotating body 3, and the operator may be encouraged to move to a work location where slipping is difficult. This notification may be made by displaying a notification display on the display unit 282 (FIG. 4), by using another device that visually notifies the operator, such as a lamp, or by an audio signal to the operator, such as a buzzer or speaker. You may use a device that notifies.

In the explanation of step S7 above, an example was explained in which the number of times it is determined that slippage has occurred is used to determine whether or not to stop automatic operation. Alternatively, this example may be controlled to stop automatic operation when the slippage amount exceeds the threshold. If the slippage amount is large, there is a possibility that the vehicle body becomes unstable due to a single slippage. By controlling the slippage amount to determine whether to stop automatic driving, the phenomenon of vehicle body instability can be more reliably avoided.

In the description of the embodiment so far, the hydraulic excavator 100 is provided with a controller 26, and the controller 26 mounted on the hydraulic excavator 100 automatically controls the operation of the work machine 2. explained. The controller that controls the operation of the work machine 2 does not necessarily have to be mounted on the hydraulic excavator 100.

12 is a schematic diagram of a system including a hydraulic excavator 100. An external controller 260 installed separately from the controller 26 mounted on the hydraulic excavator 100 may constitute a system that controls the operation of the work machine 2.

The controller 260 may be placed at the work site of the hydraulic excavator 100 or may be placed at a remote location away from the work site of the hydraulic excavator 100.

In the embodiment, control for suppressing the occurrence of slippage when slippage occurs and when the turning speed of the next turn is reduced has been described. The control for reducing the deceleration during turning deceleration explained with reference to FIG. 9 and the control for bringing the work machine 2 closer to the turning axis explained with reference to FIG. 11 are controllable not only during the next turning deceleration. For example, if slippage is detected during automatic turning, the work tool 2 is brought closer to the pivot axis (RX) immediately after slippage is detected, or the amount of decrease in turning speed per unit time is made small immediately after slippage is detected. , the rotational inertia force may be reduced.

In the embodiment, measures against slipping during rotation deceleration of the rotating body 3 were explained. The control for reducing the load carried by the bucket 8 described with reference to FIG. 10 and the control for bringing the work tool 2 closer to the pivot axis RX explained with reference to FIG. 11 are applied during the pivot acceleration of the pivot body 3. It is equally effective as a countermeasure in case slippage of the traveling body 5 occurs. Therefore, when slippage of the traveling body 5 occurs when the turning speed of the swing body 3 changes, the occurrence of slippage can be suppressed by executing processing to reduce the rotational inertia force.

In the embodiment, measures against slipping when the turning speed of the turning body 3 changes are explained. The control to reduce the load carried by the bucket 8 described with reference to FIG. 10 and the control to bring the work tool 2 closer to the pivot axis RX explained with reference to FIG. 11 are such that the pivot body 3 has a constant pivot speed. It is equally effective as a countermeasure in case slippage of the traveling body 5 occurs while turning. Therefore, when slippage of the traveling body 5 occurs during the turning operation of the swing body 3, the occurrence of slippage can be suppressed by executing processing to reduce the rotational inertial force.

In the embodiment, the hydraulic excavator 100 is described as an example of a working machine, but working machines to which the spirit of the present disclosure can be applied include a mechanical ultra-large rope excavator that is not driven by hydraulic pressure, and an electric excavator driven by an electric motor. etc., etc.

The presently disclosed embodiment should be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and is intended to include all changes within the meaning and scope equivalent to the claims.

1: Main body, 2: Work machine, 3: Swivel body, 3M: Swivel motor, 5: Traveling body, 5Cr: Crawler belt, 5M: Travel motor, 6: Boom, 7: Arm, 8: Bucket, 8a: Blade tip, 9 : Engine room, 10: Boom cylinder, 11: Arm cylinder, 12: Bucket cylinder, 21: Antenna, 21A: First antenna, 21B: Second antenna, 23: Global coordinate calculation unit, 24: IMU, 26, 260: Controller , 28: Man-machine interface part, 31: Engine, 33: Hydraulic pump, 35: Tank, 36: Engine controller, 40: Main valve, 41: Swivel spool, 42: Oil passage for hydraulic oil, 43: Supply passage, 44: Discharge. Flow path, 50: Pilot flow path, 52: Magnetic pressure reducing valve, 54: EPC valve, 61: Meter in throttle, 62: Meter out throttle, 66: Relief valve, 100: Hydraulic excavator, 102: Swivel position acquisition unit, 104 : Swing deceleration setting unit, 106: Target excavation amount setting unit, 108: Work machine attitude setting unit when turning, 200: Dump truck, 202: Carrier, 261: Memory, 281: Input unit, 282: Display unit, G: Ground plane, P: Loading, P1, P2: Payload, RX: Pivot.

Claims (6)

In working machines,
traveling body;
A swing body rotatably mounted on the traveling body;
A work machine mounted on the rotating body and having a bucket for excavating an object to be excavated; and
A controller having a target excavation amount setting unit that controls the operation of the working machine and sets a target excavation amount of the excavation object;
Equipped with
The controller determines the occurrence of slippage of the traveling body during the turning operation of the swing body during the automatic operation of the working machine, and when it is determined that slippage has occurred, the target excavation amount for the next turn. Executing processing to reduce the rotational inertia force generated during the next turning operation by changing the setting to an amount smaller than the current target excavation amount,
working machine. According to paragraph 1,
The working machine wherein the controller performs processing to reduce the rotational inertia force by reducing the amount of change in the turning speed per unit time when the turning speed at which the turning body turns with respect to the traveling body changes. According to claim 1 or 2,
Further comprising a working machine mounted on the rotating body,
The working machine wherein the controller performs a process of reducing the rotational inertial force by bringing the working machine closer to the center of rotation of the rotating body. According to claim 1 or 2,
The working machine wherein the controller stops automatic operation of the working machine when it is determined that slipping of the traveling body has occurred after executing processing for reducing the rotational inertia force. As a control method of a working machine,
The working machine includes a traveling body, a swing body rotatably mounted on the traveling body, and a work machine mounted on the swing body and having a bucket for excavating an excavation object.
Setting a target excavation amount of the excavation object;
During automatic operation of the working machine, determining whether slippage of the traveling body occurs during a turning operation of the swing body;
If it is determined that slippage has occurred in the determination step, the rotational inertia force generated during the next turning operation is reduced by setting and changing the target excavation amount for the next turn to an amount smaller than the current target excavation amount. executing processing;
A control method of a working machine comprising: In working machines,
traveling body;
A swing body rotatably mounted on the traveling body; and
a controller that controls the operation of the working machine;
Equipped with
The controller determines the occurrence of slippage of the traveling body during the turning operation of the swing body during automatic operation of the working machine, and, if it determines that slippage has occurred, the next turn of the traveling body. In contrast, when the turning speed at which the turning body turns is reduced, the timing of starting the turning speed is accelerated and the amount of reduction in turning speed per unit time is reduced, thereby performing processing to reduce the rotational inertia force generated during the turning operation.
working machine.