WO2020045020A1

WO2020045020A1 - Blade control device for work machine

Info

Publication number: WO2020045020A1
Application number: PCT/JP2019/031271
Authority: WO
Inventors: 祥平上村; 菅野　直紀; 前川　智史; 大輔野田; 佑介上村
Original assignee: 株式会社神戸製鋼所; コベルコ建機株式会社
Priority date: 2018-08-31
Filing date: 2019-08-07
Publication date: 2020-03-05
Also published as: EP3825474A1; US20210254313A1; CN112567100A; JP2020033790A

Abstract

In a blade control device (100), when an update condition set in advance is satisfied, a virtual design surface setting unit (14) defines, as a reference, a blade position when the update condition is satisfied and sets a virtual design surface (SV) at an angle equivalent to a vehicle body angle, and a blade operation control unit (15) limits a raising and lowering operation of a blade (4) such that the blade (4) performs the raising and lowering operation above the virtual design surface (SV).

Description

Work machine blade controller

The present invention relates to a blade control device provided in a work machine having a blade.

作業 Conventionally, work machines equipped with blades used for excavating the ground, leveling the ground, and transporting earth and sand have been widely used. In such a working machine, a method of automatically controlling the raising and lowering operation of the blade so that the blade load applied to the blade is almost constant has been proposed. The swell of the construction surface to be performed becomes an issue.

Patent Document 1 discloses a blade control device intended to suppress undulation on a construction surface. In the blade control device of Patent Literature 1, the blade operation control unit restricts the swing of the blade above a virtual design surface set parallel to the design surface and closer to the blade than the design surface, while reducing the blade load. When the blade load is smaller than the first set load value, the blade is lowered, and when the blade load is larger than the second set load value larger than the first set load value, the blade is raised. The virtual design surface setting unit resets a virtual design surface parallel to the design surface when the blade load decreases from a value equal to or more than the first set load value to a value smaller than the first set load value. Further, in the blade control device of Patent Document 1, the virtual design surface setting unit sets the virtual design surface at a position farther from the design surface than the previously set virtual design surface. That is, each time the virtual design surface is updated, it moves upward from the design surface.

However, in the blade control device described in Patent Literature 1 described above, for example, when the current surface (ground) has an upward gradient or a downward gradient with respect to a horizontal design surface, the work machine is located on the current surface. When performing excavation work while climbing up or down the slope along the current surface, the blade load is greatly affected by the gradient of the current surface, so that the blade elevating operation becomes large, and The effect of suppressing the swell is not sufficient.

Japanese Patent No. 5285805

The present invention provides a blade control device provided in a work machine equipped with a blade for controlling the raising and lowering operation of the blade, wherein the blade control device can effectively suppress undulation of a construction surface. The purpose is to:

The blade control device according to the present invention is provided in a work machine including a traveling device and a machine body including a vehicle body supported by the traveling device, and a blade that is attached to the machine body so as to be movable up and down. It is a device for controlling the elevating operation. The blade control device, a target design surface setting unit that sets a target design surface that specifies a target shape of an excavation target by the blade, a position information acquisition unit that acquires position information about the work machine, and the position information acquisition unit A blade position calculation unit that calculates a blade position that is the position of the blade based on the position information acquired by the above, a virtual design surface setting unit that sets a virtual design surface above the target design surface, and the blade And a blade operation control unit for controlling the elevating operation. The virtual design surface setting unit, when a preset update condition is satisfied, the horizontal plane of the vehicle body obtained based on the position information and based on the blade position when the update condition is satisfied. The virtual design surface is set at an angle equivalent to the vehicle body angle, which is an inclination angle with respect to. The blade operation control unit restricts the elevating operation of the blade so that the blade performs the elevating operation above the virtual design surface.

1 is a side view illustrating a hydraulic excavator as an example of a work machine on which a blade control device according to an embodiment of the present invention is mounted. FIG. 3 is a block diagram illustrating main functions of a blade control device according to the embodiment. 4 is a flowchart illustrating an example of a control operation executed by a controller included in the blade control device. It is a flowchart which shows an example of the control operation by the blade operation control part among the control operations performed by the controller. It is a flowchart which shows an example of the control operation by the virtual design surface setting part among the control operations performed by the controller. FIG. 4 is a schematic side view for explaining an estimated position in the blade control device. FIG. 4 is a schematic side view for explaining setting of a virtual design surface in the blade control device. It is a flowchart which shows an example of the control operation by the blade control restriction part among the control operations which the said controller performs. It is a schematic side view which shows an example of a design surface, a current surface, a virtual design surface, and a construction surface when the work machine provided with the blade control device performs excavation work while climbing a slope along a current surface. FIG. 4 is a schematic side view showing an example of a design surface, a current surface, a virtual design surface, and a construction surface when the work machine including the blade control device performs an excavation operation while descending a slope along a current surface. It is a schematic side view showing an example of a design surface, a current surface, a virtual design surface, and a construction surface when the work machine including the blade control device performs excavation work while going up and down a slope along a current surface. . FIG. 9 is a block diagram illustrating main functions of a blade control device according to a modification of the embodiment. 9 is a flowchart illustrating an example of a control operation performed by a controller included in the blade control device according to the modification. A schematic showing an example of a design surface, a current surface, a virtual design surface, and a construction surface when a work machine equipped with the blade control device according to the modification performs an excavation operation while going up and down a slope along a current surface. FIG. It is a schematic side view showing an example of a design surface, a current surface, a virtual design surface, and a construction surface when a work machine equipped with the blade control device of the reference example performs excavation work while climbing a slope along the current surface. . It is a schematic side view showing an example of a design surface, a current surface, a virtual design surface, and a construction surface when a work machine equipped with the blade control device of the reference example performs excavation work while descending a slope along the current surface. .

好ましい Preferred embodiments of the present invention will be described with reference to the drawings.

[Overall structure of work machine]
FIG. 1 is a side view showing a hydraulic excavator 1 as an example of a work machine on which a blade control device according to an embodiment of the present invention is mounted. The hydraulic excavator 1 includes a traveling device 2 (a lower traveling body) that can travel on the ground G, a vehicle body 3 (an upper revolving superstructure) mounted on the traveling device 2, and a working device mounted on the vehicle body 3. And a blade 4 mounted on the traveling device 2 or the vehicle body 3. The traveling device 2 and the vehicle body 3 constitute a machine body of the work machine. The vehicle body 3 has a turning frame, an engine, a cab, and the like.

The working device mounted on the vehicle body 3 includes a boom 5, an arm 6, and a bucket 7. The boom 5 has a base end supported at the front end of the revolving frame so as to be able to undulate, that is, rotatable around a horizontal axis, and a tip end on the opposite side. The arm 6 has a base end that is rotatably mounted on the front end of the boom 5 about a horizontal axis, and a front end opposite to the base end. The bucket 7 is rotatably attached to the tip of the arm 6.

The hydraulic excavator 1 has a boom cylinder, an arm cylinder, and a bucket cylinder provided for each of the boom 5, the arm 6, and the bucket 7. The boom cylinder is interposed between the vehicle body 3 and the boom 5, and extends and contracts so as to cause the boom 5 to perform an up-and-down operation. The arm cylinder is interposed between the boom 5 and the arm 6, and expands and contracts so as to cause the arm 6 to perform a rotating operation. The bucket cylinder is interposed between the arm 6 and the bucket 7, and expands and contracts so as to cause the bucket 7 to perform a rotating operation.

The blade 4 mounted on the traveling device 2 or the vehicle body 3 is provided for performing operations such as excavation of the ground, leveling, and transportation of earth and sand. Specifically, the blade 4 is supported by a lift frame 4a, and the lift frame 4a is supported rotatably about the horizontal axis 4b with respect to the traveling device 2. Therefore, the blade 4 can be displaced vertically with respect to the traveling device 2.

The excavator 1 has a lift cylinder 8 provided for the blade 4. The lift cylinder 8 has a head-side chamber 8h and a rod-side chamber 8r (see FIG. 1). When hydraulic oil is supplied to the head-side chamber 8h, the lift cylinder 8 extends to move the blade 4 in a lowering direction and to move the rod-side chamber 8r. While the hydraulic oil in the inside is discharged, the hydraulic oil is supplied to the rod side chamber 8r to contract and move the blade 4 in the upward direction, and to discharge the hydraulic oil in the head side chamber 8h.

The hydraulic excavator 1 has a hydraulic circuit (not shown). The hydraulic circuit includes the boom cylinder, the arm cylinder, the bucket cylinder, and the lift cylinder 8. The hydraulic circuit further includes a hydraulic pump 9 (see FIG. 1), a lift cylinder control proportional valve 41 (see FIG. 2), and a lift cylinder flow control valve (not shown).

[Blade control unit]
FIG. 2 is a block diagram illustrating main functions of the blade control device 100. The blade control device 100 is provided to control the elevating operation of the blade 4. The blade control device 100 includes a controller 10 (mechatronic controller), a position information acquisition unit, a blade load acquisition unit 34, an automatic control switch 35, and a traveling lever 36 for operating the traveling device 2. The controller 10 includes, for example, a microcomputer and controls the operation of each element included in the hydraulic circuit.

位置 The position information acquisition unit has a function of acquiring position information on the excavator 1. Specifically, in the present embodiment, the position information acquisition unit includes a vehicle body position acquisition unit 31, a vehicle body angle acquisition unit 32, and a blade angle acquisition unit 33. The vehicle body position acquisition unit 31 has a function of acquiring a vehicle body position that is the position of the machine body. The vehicle body position acquisition unit 31 is configured by a receiver capable of receiving satellite data (positioning signal) from a satellite positioning system, such as a receiver (GNSS sensor) of GNSS (Global Navigation Satellite System), for example, and the vehicle body in a global coordinate system. The GNSS data indicating the vehicle body position which is the position 3 is received. The global coordinate system is a three-dimensional coordinate system based on an origin defined on the earth, and is a coordinate system indicating an absolute position defined by the satellite positioning system.

The vehicle body angle obtaining unit 32 has a function of obtaining a vehicle body angle which is an angle of the vehicle body 3. The vehicle body angle acquisition unit 32 is configured by, for example, a vehicle body angle sensor that detects the angle of the vehicle body 3 in the global coordinate system. Specifically, the vehicle body angle sensor may be provided, for example, in the body of the aircraft, and may include one or a plurality of receivers capable of receiving satellite data (positioning signal) from a satellite positioning system. The vehicle body angle is a tilt angle of the vehicle body with respect to a horizontal plane.

ブレード The blade angle acquisition unit 33 has a function of acquiring the angle of the blade 4. The blade angle acquisition unit 33 is configured by, for example, a blade angle sensor that detects the angle of the blade 4 in the global coordinate system. Specifically, the blade angle sensor may be provided in, for example, the body of the aircraft, and may be configured by one or a plurality of receivers capable of receiving satellite data (positioning signal) from a satellite positioning system.

Note that, instead of the global coordinate system, a local coordinate system such as a three-dimensional coordinate system based on the vehicle body position or a three-dimensional coordinate system based on a specific position in a work site may be used. The global coordinate system and the local coordinate system may be used together. In this case, the vehicle body angle sensor may be configured by, for example, an inertial measurement device, or may be configured by the inertial measurement device and the receiver that can receive the satellite data. The inertial measurement device measures, for example, the acceleration and angular velocity of the vehicle body 3, and based on the measurement result, tilts the vehicle body 3 (for example, pitch indicating rotation about the X axis, yaw indicating rotation about the Y axis, and rotation about the Z axis). May be configured to be detectable. Further, the blade angle sensor may be configured by, for example, a stroke sensor that detects a cylinder stroke of the blade cylinder 8, or may be configured by the stroke sensor and the receiver that can receive the satellite data.

As shown in FIG. 1, in the present embodiment, the vehicle body position obtaining unit 31 and the vehicle body angle obtaining unit 32 are mounted on the upper part of the vehicle body 3, and the blade angle obtaining unit 33 is mounted on the upper part of the blade 4. Is not limited to the specific example shown in FIG. Detection signals, which are electric signals generated by the

acquisition units

31, 32, and 33, are input to the controller 10.

In the present embodiment, the blade load obtaining unit 34 has a function of obtaining a blade load that is a load applied to the blade 4 during excavation work. The blade load corresponds to, for example, the pump pressure of the hydraulic pump 9 that drives the blade 4. Therefore, the blade load acquisition unit 34 can detect the blade load by detecting the pump pressure. In the present embodiment, the blade load acquisition unit 34 includes a head pressure sensor 34H that detects a head pressure P1 that is a pressure of hydraulic oil in the head-side chamber 8h of the lift cylinder 8, and a hydraulic pressure in the rod-side chamber 8r of the lift cylinder 8. And a rod pressure sensor 34R for detecting a rod pressure P2 as a pressure. Each of the

sensors

34H and 34R converts the detected physical quantity into a detection signal, which is an electric signal corresponding to the detected physical quantity, and inputs the detection signal to the controller 10.

The automatic control switch 35 is arranged in the cab and is electrically connected to the controller 10. The automatic control switch 35 receives an operation for switching the control mode of the controller 10 from the manual operation mode to the automatic control mode, and inputs a mode command signal relating to the operation to the controller 10. The controller 10 switches the setting of the control mode from the manual operation mode to the automatic control mode according to a mode command signal input from the automatic control switch 35.

In the automatic control mode, the controller 10 is configured to automatically control the operation of the lift cylinder 8 so that the construction surface constructed by the blade 4 approaches a preset target design surface. When a command value (command current) to the lift cylinder control proportional valve 41 for controlling the operation of the lift cylinder 8 is output from the controller 10, the secondary pressure of the proportional valve 41 is increased according to the command value. The opening degree of the lift cylinder flow control valve changes according to the secondary pressure. As a result, the supply flow rate and the supply direction of the hydraulic oil supplied from the hydraulic pump 9 to the lift cylinder 8 via the lift cylinder flow control valve change, and the operation speed and the drive direction of the lift cylinder 8 are controlled. On the other hand, in the manual operation mode, when an operator operates the traveling lever 36, an operation signal is input to the controller 10, and the operation signal is input to the controller 10 according to the operation amount of an unillustrated operation lever for operating the elevation of the blade 4. A command value to the lift cylinder control proportional valve 41 or a command value to the lift cylinder flow control valve is output from the controller 10.

The controller 10 includes a target design surface setting unit 11, a blade position calculation unit 12, a storage unit 13, a virtual design surface setting unit 14, a blade operation control unit 15 as functions for executing the automatic control. , A load threshold setting unit 16, a blade control restriction unit 20, and an estimated position calculation unit 22.

The target design surface setting unit 11 sets a target design surface SD (see FIG. 7) for specifying a target shape to be excavated by the blade 4. The target design surface setting unit 11 may store a design surface input by a target design surface input unit provided in the cab, and may set the design surface as a target design surface. Further, the target design surface setting unit 11 may store design surface data acquired via various storage media, a communication network, or the like, and set the design surface as a target design surface. The target design plane setting unit 11 inputs the set target design plane to the virtual design plane setting unit 14. The target design surface SD is a surface which is a target shape of the ground to be excavated and specifies a three-dimensional design topography. The target design plane SD may be specified by external data such as BIM or CIM (Building / Construction / Information / Modeling, Management), or may be set based on the position of the work machine.

The blade position calculator 12 calculates a blade position, which is a position of the blade 4 in a global coordinate system, based on the position information acquired by the position information acquirer. In the present embodiment, the blade position calculation unit 12 includes the vehicle body position acquired by the vehicle body position acquisition unit 31, the vehicle body angle acquired by the vehicle body angle acquisition unit 32, and the blade position acquired by the blade angle acquisition unit 33. The blade position is calculated based on the angle of the blade 4. That is, the blade position is calculated from the sum of a vector from the reference point to the vehicle body position and a vector from the vehicle body position to the blade position. As described above, in the present embodiment, the blade position is calculated based on the relative angle between the vehicle body angle and the angle of the blade 4 in the global coordinate system, but the method of calculating the blade position is not limited to this. The blade position may be calculated based on, for example, the length of the lift cylinder 8, or a GNSS receiver (GNSS sensor) may be attached to the blade 4 and calculated based on GNSS data received by the GNSS sensor.

In the present embodiment, the blade position is set at the cutting edge position (the position of the lower edge of the tip of the blade 4), which is the tip of the blade 4, but may be set at another part of the blade 4.

記憶 The storage unit 13 stores a first load threshold f1 as a load threshold which is a threshold of the blade load f. In the present embodiment, the storage unit 13 further stores a second load threshold f2 which is a threshold of the blade load f. The first load threshold f1 and the second load threshold f2 will be described later.

(4) The storage unit 13 stores a preset update condition. The update condition serves as a reference for determining whether or not the virtual design surface setting unit 14 updates a virtual design surface described later. The update condition includes one or more conditions. Details of the update condition will be described later.

When the update condition is satisfied, the virtual design surface setting unit 14 sets the vehicle body angle acquired by the vehicle body angle acquisition unit 32 based on the blade position when the update condition is satisfied. A parallel virtual design surface is set above the target design surface. In the virtual design surface setting unit 14, the blade position calculated by the blade position calculation unit 12, the first load threshold f1 set by the load threshold setting unit 16, and the blade load f acquired by the blade load acquisition unit 34. The vehicle position acquired by the GNSS receiver (vehicle position acquisition unit 31), the vehicle body angle acquired by the vehicle angle sensor (vehicle angle acquisition unit 32), the target design surface set by the target design surface setting unit 11, The virtual design surface is set based on. A specific setting method will be described later.

The load threshold setting unit 16 sets a load threshold used for calculation in the virtual design plane setting unit 14 and the blade operation control unit 15. In the present embodiment, the load threshold setting unit 16 sets the first load threshold f1 and the second load threshold f2 described above. The second load threshold f2 is set to a value larger than the first load threshold f1. The first load threshold f1 is set to a value corresponding to an appropriate blade load f at which the excavator 1 can run stably. The second load threshold f2 is a value set to realize a stable and efficient excavation operation. The second load threshold f2 is a value set to prevent the occurrence of a situation in which the blade load f becomes excessive and a stack or the like occurs, and is therefore smaller than the blade load in which the situation occurs. Preferably, it is set to a value. That is, the second load threshold f2 is preferably set to a value at which the work machine can travel even when the blade load f has reached the second load threshold f2. These load thresholds f1 and f2 may be manually input to the controller 10 by the operator before the excavation work, or may be appropriately calculated and stored by the controller 10 during the excavation work.

The blade operation control unit 15 calculates and outputs a command value to the lift cylinder control proportional valve 41 for controlling the operation of the lift cylinder 8. The blade operation control unit 15 includes an automatic control switch operation signal of the automatic control switch 35, a traveling lever operation signal of the traveling lever 36, a blade load f acquired by the blade load acquiring unit 34, and a setting by the load threshold setting unit 16. Based on the first load threshold value f1 and the second load threshold value f2, a provisional command current to be output to the lift cylinder control proportional valve 41 is calculated. A specific calculation method will be described later.

The blade control restriction unit 20 outputs a command to the lift cylinder control proportional valve 41 based on the virtual design surface calculated by the virtual design surface setting unit 14 and the provisional command current calculated by the blade operation control unit 15. Calculate the current. A specific calculation method will be described later.

The estimated position calculation unit 22 calculates the estimated position of the current plane, which forms part of the update conditions. Specifically, the estimated position calculating unit 22 obtains, by the position information obtaining unit, an estimated position of a part associated with at least one of the blade 4 and the traveling device 2 on a current surface that is the ground to be excavated. The calculation is performed based on the position information. A specific calculation method will be described later.

Next, a control operation performed by the controller 10 for driving the blade 4 in the automatic control mode will be described with reference to a flowchart of FIG.

The controller 10 acquires an automatic control switch operation signal relating to the automatic control switch 35 and a traveling lever operation signal relating to the traveling lever 36 (step S1).

Next, the controller 10 satisfies the condition that the automatic control switch operation signal indicates that the automatic control switch 35 is on and that the traveling lever operation signal indicates that the traveling lever 36 has been operated. It is determined whether or not (step S2). If the condition is not satisfied (NO in step S2), controller 10 resets the virtual design surface and ends the process.

If the condition is satisfied (YES in step S2), the load threshold setting unit 16 sets the first load threshold f1 and the second load threshold f2 (step S3).

Next, the blade load acquiring unit 34 acquires the blade load f applied to the blade 4 (Step S4).

Next, the blade operation control unit 15 calculates the provisional command current (step S5). FIG. 4 is a diagram showing a flow in which the blade operation control unit 15 of the controller 10 calculates the provisional command current. As shown in FIG. 4, the blade operation control unit 15 determines whether or not the condition that the blade load f acquired by the blade load acquisition unit 34 is equal to or more than the second load threshold f2 is satisfied (Step S101). If the condition is satisfied (YES in step S101), blade operation control unit 15 outputs a provisional command current corresponding to "lift up", and ends the process. The provisional command current is input to the blade control limiting unit 20. “Lift raising” corresponds to an operation of raising the blade 4.

If the condition in step S101 is not satisfied (NO in step S101), the blade operation control unit 15 determines whether the condition that the blade load f is equal to or greater than the first load threshold f1 is satisfied (step S102). . When the condition in Step S102 is satisfied (YES in Step S102), the blade operation control unit 15 outputs a provisional command current corresponding to “lift fixed”, and ends the process. The provisional command current is input to the blade control limiting unit 20. “Lift fixed” corresponds to not performing the raising / lowering operation of the blade 4.

場合 If the above condition of step S102 is not satisfied (NO in step S102), blade operation control unit 15 outputs a provisional command current corresponding to “lift down”, and ends the process. The provisional command current is input to the blade control limiting unit 20. “Lift lowering” corresponds to the operation of lowering the blade 4.

フロー The flow shown in FIG. 4 is a process for maintaining the blade load f during excavation work within the range between the first load threshold f1 and the second load threshold f2. In this flow, when the blade load f is equal to or more than the second load threshold f2, it is considered that a load exceeding the excavation capacity of the blade 4 is applied to the blade 4, and the “lift lift” is set to reduce the blade load f. Is performed. When the blade load f is smaller than the first load threshold f1, the load on the blade 4 is considered to be too small for the excavation ability, and a “lift lowering” operation is performed to increase the excavation amount. In other cases, a process of fixing the position of the blade 4, that is, a process of not performing the elevating operation of the blade 4 is performed.

Next, in step S6 shown in FIG. 3, the controller 10 determines whether or not the condition that the provisional command current output by the blade operation control unit 15 corresponds to “lift up” is satisfied (step S6). S6). If the condition is satisfied (YES in step S6), the blade control restriction unit 20 performs the processing in step S11. If the condition is not satisfied (NO in step S6), a series of processes in the following steps S7 to S11 is performed.

The vehicle body position obtaining unit 31 obtains the vehicle body position, the vehicle body angle obtaining unit 32 obtains the vehicle body angle, and the blade angle obtaining unit 33 obtains the angle of the blade 4 (Step S7). The blade position calculator 12 calculates the blade position based on the vehicle body position, the vehicle body angle, and the angle of the blade 4 (Step S8).

Next, the virtual design surface setting unit 14 sets a virtual design surface (step S9). FIG. 5 is a diagram illustrating a flow in which the virtual design surface setting unit 14 of the controller 10 sets a virtual design surface. First, the virtual design surface setting unit 14 determines whether a condition corresponding to no virtual design surface being set is satisfied (step S201). In the specific example shown in FIG. 5, in step S201, the virtual design surface setting unit 14 determines whether or not step S201 is the first step of the automatic control. If the step S201 is the first step of the automatic control, the virtual design surface is not necessarily set. Therefore, whether or not the first step of the automatic control is the virtual design surface is determined. It can be determined whether or not the condition corresponding to the absence of the event is satisfied. Further, the determination as to whether or not the condition corresponding to the fact that the virtual design surface has not been set can also be performed based on, for example, a flag (setting flag) indicating setting or non-setting of the virtual setting surface. .

When the virtual design surface setting unit 14 determines that the step is the first step of the automatic control (YES in step S201), the virtual design surface setting unit 14 newly sets a virtual design surface and ends the process. If the virtual design surface setting unit 14 determines that the step is not the first step of the automatic control (NO in step S201), the blade load f previously obtained by the blade load obtaining unit 34 is equal to or more than the first load threshold f1. It is determined whether or not the condition that the blade load f acquired this time by the blade load acquisition unit 34 is smaller than the first load threshold f1 is satisfied (step S202). If the condition is satisfied (YES in step S202), virtual design surface setting unit 14 newly sets a virtual design surface (updates the virtual design surface), and ends the process.

If the condition in step S202 is not satisfied (NO in step S202), it is determined whether the condition that the estimated position is below the virtual design surface is satisfied (step S203). When it is determined that the condition of step S203 is satisfied (YES in step S203), virtual design surface setting unit 14 newly sets a virtual design surface (updates the virtual design surface) and ends the process. . If the condition in step S203 is not satisfied (NO in step S203), virtual design surface setting unit 14 ends the process without updating the virtual design surface.

フロー The flow shown in FIG. 5 is a process for appropriately setting the virtual design surface SV. In this flow, the condition "it is the first step of the automatic control" (step S201), "the blade load f acquired last time is equal to or more than the first load threshold f1, and the blade load f acquired this time is the At least one of the following condition is satisfied (Step S202): "It is smaller than one load threshold f1"; and (Step S203): "The estimated position is below the currently set virtual design surface SV". In this case, a process of newly setting the virtual design surface SV (a process of updating the virtual design surface SV) is performed. By performing this processing, the virtual design surface SV is set at an appropriate time, and stable excavation work with high construction efficiency is realized.

FIG. 6 is a schematic side view for explaining the estimated position. The estimated position PB shown in FIG. 6 is calculated by the estimated position calculation unit 22. Since the blade 4 and the traveling device 2 are arranged below the work machine, they are located at a height close to the height of the current plane SP. Therefore, at least one of the blade 4 and the traveling device 2 can be an index when determining the positional relationship between the virtual design surface SV and the current surface SP. The estimated position PB calculated by the estimated position calculation unit 22 is a part of the current surface SP associated with at least one of the blade 4 and the traveling device 2 based on the position information. Is calculated and estimated. Therefore, when the condition that the estimated position PB is below the virtual design plane SV is satisfied, the possibility that the blade 4 is floating above the current plane SP increases. When the update condition including the above condition is satisfied, the virtual design surface SV is updated to an angle parallel to the vehicle body angle based on the blade position, so that the state where the blade 4 floats above the current surface SP is eliminated. Is done.

In the present embodiment, the estimated position PB is, as shown in FIG. 6, a line parallel to the lower part of the traveling device 2 in the work machine (a line on the current plane SP in FIG. 6) and a virtual design plane passing through the blade position. This is the intersection of a line L extending vertically from the SV. Since the estimated position PB is the estimated height position of the current plane SP at the blade position, the estimated position PB may be, for example, a point where the line parallel to the lower part of the traveling device 2 of the work machine and the blade 4 intersect. .

FIG. 7 is a schematic side view for explaining a setting method of the virtual design surface SV in the blade control device 100. In the present embodiment, as shown in FIG. 7, when the update condition is satisfied, the virtual design plane setting unit 14 sets the virtual design plane setting section 14 in advance on the straight line passing through the blade position and perpendicular to the target design plane SD from the blade position. A reference position below the reference distance δ is calculated, and a plane passing through the reference position and parallel to the vehicle body angle is set as a virtual design plane SV.

Next, in step S10 shown in FIG. 3, the blade control limiting unit 20 calculates the command current. FIG. 8 is a diagram showing a flow in which the blade control restriction unit 20 of the controller 10 calculates the command current. As shown in FIG. 8, the blade control restriction unit 20 determines whether or not the condition that the blade position calculated by the blade position calculation unit 12 is below the virtual design surface SV is satisfied (step S301). . If the condition is satisfied (YES in step S301), blade control restriction unit 20 sets the command current corresponding to "lift up", and ends the process. “Lift raising” corresponds to an operation of raising the blade 4. On the other hand, when the condition is not satisfied (NO in step S301), blade control restriction unit 20 sets the command current to the same as the provisional command current input from blade operation control unit 15, and ends the process. .

フロー The flow shown in FIG. 8 is a process for maintaining the blade position above the virtual design surface SV. For example, even if the calculation result by the blade operation control unit 15 corresponds to “lift down” or “lift fixed” (that is, the blade load f is small with respect to the excavating ability of the blade 4). Also, when the blade control limiting unit 20 determines that the blade position is below the virtual design surface SV, the command current is overwritten to “lift up” so that the blade position does not fall below the virtual design surface SV. Processing is performed. This prevents undulations on the construction surface SC.

において In step S11 shown in FIG. 3, the blade control restricting unit 20 outputs the command current to the lift cylinder control proportional valve 41. Specifically, when the condition that the provisional command current output by the blade operation control unit 15 corresponds to “lift up” is satisfied (YES in step S6), the blade control restriction unit 20 sets The same command current as the command current is output to the proportional valve 41. If NO in step S6, the blade control restriction unit 20 outputs the command current calculated in step S10 to the proportional valve 41. When the processing in step S11 ends, the controller 10 performs the processing in step S1 again.

In the following, advantages of the blade control device 100 according to the present embodiment will be specifically described in comparison with the blade control device of the reference example.

FIG. 15 shows a design plane SD (target design plane), a current plane SP1, SP2, and a virtual plane when a work machine equipped with the blade control device of the reference example performs an excavation work while climbing a slope along the current planes SP1 and SP2. It is an outline side view showing an example of design side SV11, SV12, SV13, SV21 and construction side SC1, SC2.

In the reference example shown in FIG. 15, since the virtual design surface SV11 is parallel to the design surface SD, the distance between the current surface SP1 and the virtual design surface SV11 increases as going up the ascending slope. Therefore, as shown in the upper diagram of FIG. 15, as the work machine goes up the slope along the current plane SP1 while excavating the current plane SP1, the blade load becomes significantly large. When the blade load becomes larger than the second predetermined threshold, the blade operation controller raises the blade 104, so that the blade load gradually decreases. When the blade load becomes smaller than a predetermined first threshold (a value smaller than the second threshold), the virtual design surface setting unit updates the virtual design surface SV11 to the virtual design surface SV12. The updated virtual design surface SV12 is set in parallel with the horizontal design surface SD, and is set above the previously set virtual design surface SV11. In this manner, during the first excavation operation in which the work machine climbs up the slope along the current plane SP1 and excavates the entire current plane SP1, a plurality of horizontal excavations are performed as shown in the upper diagram of FIG. The virtual design surfaces SV11, SV12, and SV13 are set in steps, and the construction surface SC1 formed by the first excavation work is also formed in steps. The first construction surface SC1 formed in a stepped manner as described above becomes the current surface SP2 to be excavated in the second excavation operation to be performed next (see the lower diagram in FIG. 15). Therefore, as shown in the lower diagram of FIG. 15, in the second excavation operation, when the work machine goes up the slope along the current surface SP2 while excavating the current surface SP2, the body of the work machine moves in the pitch direction. Shaking greatly. This causes a decrease in controllability for controlling the attitude of the work machine and in ride comfort of the worker.

FIG. 16 shows the design surface SD, the current surface SP, the virtual design surface SV11, and the construction surface SC when the work machine equipped with the blade control device of the reference example performs the excavation work while descending the slope along the current surface SP. It is an outline side view showing an example. The virtual design surface SV21 in the lower diagram of FIG. 15 is a virtual design surface set for the second excavation work, and is a virtual design surface parallel to the target design surface SD.

In the reference example shown in FIG. 16, since the virtual design surface SV11 is parallel to the design surface SD, the distance between the current surface SP and the virtual design surface SV11 decreases as the position goes down the downhill. Therefore, as shown in the upper diagram of FIG. 16, when the work machine goes down a slope along the current plane SP while excavating the current plane SP, an area where the horizontal virtual design surface SV11 exceeds the current plane SP is inevitably. Occurs. In the region where the virtual design surface SV11 exceeds the current surface SP, as shown in the middle diagram of FIG. 16 and the lower diagram of FIG. Inevitably, the current plane SP is floated above the current plane SP, and the current plane SP cannot be excavated. Moreover, since the virtual design surface updated when the blade load becomes smaller than the first threshold value is set further above the previous virtual design surface SV11, the blade 104 floats further above the current surface SP. State. This causes a decrease in construction efficiency.

On the other hand, in the blade control device 100 according to the present embodiment, since the virtual design surface SV set by the virtual design surface setting unit 14 is not parallel to the target design surface SD but parallel to the vehicle body angle, The undulation of the construction surface SC can be suppressed, and the controllability of the posture of the work machine at the time of excavation work, ride comfort, and deterioration of construction efficiency can be suppressed. Specifically, it is as follows.

FIG. 9 shows a design plane SD (target design plane), a current plane SP, and a virtual design when the work machine including the blade control device 100 according to the present embodiment performs excavation work while climbing a slope along the current plane SP. FIG. 10 is a schematic side view showing an example of a surface SV and a construction surface SC, and FIG. 10 is a schematic side view showing an example when the work machine performs excavation work while descending a slope along the current surface SP. is there. FIG. 11 is a schematic side view showing an example when the work machine performs excavation work while going up and down a slope along the current plane SP.

As shown in FIG. 9, in the present embodiment, the virtual design surface SV is set in parallel with the vehicle body angle of the work machine traveling up the slope along the current surface SP of the upward slope. The staircase is not set as in the reference example shown in the upper diagram of FIG. 15, and as a result, the construction surface SC is also prevented from being formed in a staircase. For this reason, when excavating the construction surface SC again, the swing of the vehicle body in the pitch direction is suppressed, and the effect of eliminating the deterioration of the controllability of the posture of the work machine and the deterioration of the riding comfort can be obtained.

As shown in FIG. 10, setting the virtual design surface SV in parallel to the vehicle body angle of the work machine going down the slope along the current surface SP of the downward slope requires that the virtual design surface SV be set along the current surface SP of the downward slope. The virtual design surface SV parallel to the vehicle body angle of the work machine in the inclined posture (downward slope virtual design surface SV) can be reset. This makes it possible to eliminate the state even if the virtual design plane SV exceeds the current plane SP, thereby suppressing a reduction in construction efficiency.

{Furthermore, the blade control device 100 according to the present embodiment is also effective when the current surface has relatively large irregularities as shown in FIG. In the present embodiment, the virtual design surface SV can have various angles according to the vehicle body angle. This means that, as shown in FIG. 11, a plurality of virtual design surfaces set during the first excavation operation in which the work machine climbs up the slope along the current surface SP and excavates the entire current surface. SV1, SV2, SV3, and SV4 are prevented from being formed in a horizontal step shape as in the reference example. That is, each of the plurality of virtual design surfaces SV1, SV2, SV3, SV4 formed in the first excavation work is set in parallel with the vehicle body angle of the work machine in a posture along the uphill current plane SP. The plurality of virtual design planes SV tend to be along the upward slope of the current plane SP. This suppresses that the construction surface SC formed in the first excavation work by the blade 4 whose elevation operation is restricted based on the virtual design surface SV1, SV2, SV3, SV4 is formed in a step shape, As compared with the reference example, it is easy to have less unevenness. Therefore, in the second excavation operation performed using the first construction surface SC as the current surface, when the work machine climbs up a slope along the current surface while excavating the current surface, the body of the work machine moves at the pitch. Swing in the direction is suppressed. This suppresses a decrease in controllability for controlling the posture of the work machine and a decrease in ride comfort of the worker. In addition, undulation is suppressed on the construction surface excavated by the blade 4 whose elevation operation is restricted based on the virtual design surfaces SV1, SV2, SV3, and SV4 as described above.

[Modification]
FIG. 12 is a block diagram illustrating main functions of a blade control device 100 according to a modification of the present embodiment. FIG. 13 is a flowchart illustrating an example of a control operation executed by the controller 10 included in the blade control device 100 according to the modification. FIG. 14 shows a design surface SD, a current surface SP, a virtual design surface SV, when a work machine including the blade control device 100 according to the modification performs an excavation operation while going up and down a slope along the current surface SP. And a schematic side view showing an example of a construction surface SC.

The blade control device 100 according to the modified example shown in FIG. 12 differs from the blade control device 100 shown in FIG. 2 in that the controller 10 further includes a vehicle body average angle calculation unit 21, and other configurations are shown in FIG. It is the same as the blade control device 100. Further, the flowchart shown in FIG. 13 is different from the flowchart shown in FIG. 3 in that the process of step S12 is added between the process of step S8 and the process of step S9, and other processes are shown in FIG. It is the same as the flowchart.

The vehicle body average angle calculation unit 21 calculates an average value of the vehicle body angle acquired by the position information acquisition unit. In the modified example, the virtual design surface setting unit 14 is configured to use the average value of the vehicle body angle as the vehicle body angle that is a reference when setting the virtual design surface SV.

In this modification, as shown in FIG. 14, even when the current surface SP to be excavated has relatively large irregularities, the virtual design surfaces SV1, SV2, SV3, and SV4 are different from the average value of the vehicle body angle. Since the virtual design surfaces SV2, SV3, and SV4 are set in parallel, the update timing of the virtual design surfaces SV2, SV3, and SV4 is less likely to be affected by local irregularities. This makes it possible to reduce the amount of change in the angle at the time of updating the virtual design surfaces SV2, SV3, and SV4, thereby enabling more stable excavation work.

The average value of the vehicle body angle is, for example, a moving average of a plurality of vehicle body angles acquired by the vehicle body angle acquisition unit 32 between a time when the virtual design surface SV is updated and a time that is a predetermined time before the time. Although a value can be adopted, the method of calculating the average value is not limited to the above method.

In this modification, when the update condition is satisfied, the virtual design plane setting unit 14 sets a reference distance δ which is lower than the blade position by a preset reference distance δ on a straight line passing through the blade position and perpendicular to the target design plane SD. A reference position is calculated, and a plane passing through the reference position and parallel to the average value of the vehicle body angle is set as a virtual design plane SV. That is, in the modification, the virtual design surface is set in parallel with the average value of the vehicle body angle in the continuous time, so that even if the current surface has irregularities, the virtual design surface SV Is along the average angle of the vehicle body, that is, along the average gradient of the current plane. This makes it possible to reduce the amount of change in the angle at the time of updating the virtual design surface, thereby enabling more stable excavation.

To give a specific example, in the modification shown in FIG. 14, the virtual design surface SV is set in parallel to the average of the vehicle body angles in continuous time, so that the virtual design surface SV is virtual compared to the embodiment shown in FIG. The amount of change in the angle at the time of updating the design surface can be reduced, which has the effect of eliminating the deterioration of construction efficiency and has the effect of enabling more stable excavation.

The present invention is not limited to the embodiment described above. The present invention includes the following embodiments, for example.

The work machine to which the blade control device according to the present invention is applied is not limited to a hydraulic shovel. The present invention can be widely applied to other work machines including a blade, such as a wheel loader and a bulldozer.

As described above, a blade control device capable of effectively suppressing undulation on a construction surface is provided.

The blade control device is provided in a work machine including a machine body including a traveling device and a vehicle body supported by the traveling device, and a blade attached to the machine body so as to be able to move up and down. Is a device for controlling the The blade control device, a target design surface setting unit that sets a target design surface that specifies a target shape of an excavation target by the blade, a position information acquisition unit that acquires position information about the work machine, and the position information acquisition unit A blade position calculation unit that calculates a blade position that is the position of the blade based on the position information acquired by the above, a virtual design surface setting unit that sets a virtual design surface above the target design surface, and the blade And a blade operation control unit for controlling the elevating operation. The virtual design surface setting unit is configured such that, when a preset update condition is satisfied, the horizontal plane of the vehicle body obtained based on the position information while referring to the blade position when the update condition is satisfied. The virtual design surface is set at an angle equivalent to the vehicle body angle, which is an inclination angle with respect to. The blade operation control unit limits the lifting operation of the blade so that the blade performs the lifting operation above the virtual design surface.

In this blade control device, the virtual design surface is not set parallel to the target design surface, but is set parallel to the vehicle body angle. Thus, for example, the current plane (ground) has an upward or downward slope with respect to the horizontal target design plane, and the work machine is traveling uphill or downhill along the current plane. When performing an excavation work, the virtual design surface is likely to be along an upward slope or a downward slope. This suppresses fluctuations in the distance between the current plane and the virtual design plane, thereby suppressing fluctuations in the blade load. When the fluctuation of the blade load is suppressed, the raising / lowering operation of the blade is suppressed, so that the undulation of the construction surface is suppressed.

The blade control device, based on the position information acquired by the position information acquisition unit the estimated position of the site associated with at least one of the blade and the traveling device in the current surface that is the ground of the excavation target It is preferable that the apparatus further includes an estimated position calculating unit for calculating, and the update condition includes a condition that the estimated position is below the virtual design surface.

If the current plane (ground) to be excavated has relatively large irregularities, the body angle of the work machine also fluctuates relatively largely, and the virtual design plane set parallel to the body angle also has a relatively large angle range. It becomes easy to be set. In such a case, during the excavation work, the virtual design surface may be temporarily located higher than the portion corresponding to the blade in the current surface or the portion corresponding to the traveling device in the current surface. The blade restricted above the plane may float above the current plane. If such a state continues for a long time, the efficiency of the excavation operation decreases. Here, since the blade and the traveling device are arranged below the work machine, they are located at a height close to the height position of the current plane. Therefore, at least one of the blade and the traveling device can be an index when determining the positional relationship between the virtual design surface and the current surface. In this aspect, the estimated position calculated by the estimated position calculation unit is calculated by the estimated position calculation unit based on the position information on a portion of the current surface associated with at least one of the blade and the traveling device. It is estimated. Therefore, when the condition that the estimated position is below the virtual design plane is satisfied, there is a high possibility that the blade will be in a state of floating above the current plane. In this aspect, when the update condition including the condition is satisfied, the virtual design surface is updated to the same angle as the vehicle body angle based on the blade position, so that the blade floats above the current surface. The condition is resolved.

In the blade controller, it is preferable that the update condition includes a condition corresponding to the fact that the virtual design surface has not been set. For example, if a virtual design surface is not set at the start of automatic blade control, a virtual design surface parallel to the vehicle body angle is set when an update condition including the condition is satisfied. As a result, excavation work with high construction efficiency can be performed from the initial stage of automatic blade control.

The blade control device further includes a blade load acquisition unit that acquires a blade load that is a load applied to the blade, and a storage unit that stores a load threshold that is a threshold value of the blade load. It is preferable to include a condition that the blade load changes from a value equal to or greater than the load threshold to a value smaller than the load threshold.

とき When the blade load changes from a value equal to or more than the load threshold to a value smaller than the load threshold, it often corresponds to a case where an operation for reducing the load applied to the blade is being performed. Thus, the state when the blade load is reduced is more desirable than the state when the blade load is increased, from the viewpoint of stability of excavation work. Therefore, the virtual design surface is set when the update condition including the condition is satisfied, and the excavation work in which the raising / lowering operation of the blade is restricted based on the virtual design surface is performed, so that the stability of the excavation work is reduced. improves.

The blade control device further includes a vehicle body average angle calculation unit that calculates an average value of the vehicle body angle acquired by the position information acquisition unit, and the virtual design surface setting unit sets the virtual design surface. It is preferable that the average value of the vehicle body angles is used as the reference vehicle body angle. In this aspect, even when the current surface to be excavated has relatively large irregularities, the virtual design surface is set parallel to the average value of the vehicle body angle, so that the virtual design surface is locally updated. Less likely to be affected by irregularities. This makes it possible to reduce the amount of change in the angle at the time of updating the virtual design surface, thereby enabling more stable excavation work.

Claims

A blade provided on a work machine including a traveling device and a machine body including a vehicle body supported by the traveling device, and a blade that is attached to the machine body so as to be able to move up and down, and controls a lifting operation of the blade. A control device,
A target design surface setting unit that sets a target design surface that specifies a target shape of the excavation target by the blade,
A position information acquisition unit that acquires position information about the work machine,
A blade position calculation unit that calculates a blade position that is a position of the blade based on the position information acquired by the position information acquisition unit,
A virtual design surface setting unit that sets a virtual design surface above the target design surface,
A blade operation control unit that controls the elevating operation of the blade,
The virtual design surface setting unit is configured such that, when a preset update condition is satisfied, the horizontal plane of the vehicle body obtained based on the position information while referring to the blade position when the update condition is satisfied. The virtual design surface is set to an angle equivalent to the vehicle body angle that is an inclination angle with respect to,
The blade control device, wherein the blade operation control unit limits the lifting operation of the blade so that the blade performs the lifting operation above the virtual design surface.
An estimated position calculating unit that calculates an estimated position of a portion associated with at least one of the blade and the traveling device on the current surface that is the ground to be excavated based on the position information acquired by the position information acquiring unit. Further comprising
The blade control device according to claim 1, wherein the update condition includes a condition that the estimated position is below the virtual design surface.
3. The blade control device according to claim 1, wherein the update condition includes a condition corresponding to the fact that the virtual design surface is not set. 4.
A blade load acquisition unit that acquires a blade load that is a load applied to the blade,
A storage unit that stores a load threshold value that is a threshold value of the blade load,
4. The blade control device according to claim 1, wherein the update condition includes a condition that the blade load changes from a value equal to or larger than the load threshold to a value smaller than the load threshold.
The vehicle further includes a vehicle body average angle calculation unit that calculates an average value of the vehicle body angle acquired by the position information acquisition unit,
The blade control device according to any one of claims 1 to 4, wherein the virtual design surface setting unit uses the average value of the vehicle body angle as the vehicle body angle serving as a reference when setting the virtual design surface. .