CN107636236B

CN107636236B - Excavator

Info

Publication number: CN107636236B
Application number: CN201680034252.3A
Authority: CN
Inventors: 冈田纯一
Original assignee: Sumitomo Heavy Industries Ltd
Current assignee: Sumitomo Heavy Industries Ltd
Priority date: 2015-08-31
Filing date: 2016-08-29
Publication date: 2022-01-11
Anticipated expiration: 2036-08-29
Also published as: JP6851701B2; JPWO2017038772A1; CN107636236A; WO2017038772A1

Abstract

The invention provides an excavator. The slewing device of the present invention rotates an upper slewing body with respect to a crawler. The attachment (12) has a boom, an arm, a bucket, a boom cylinder, an arm cylinder, and a bucket cylinder, and is attached to the upper slewing body. The controller (30) restricts the operation of at least one of the attachment (12) and the upper slewing body so as to prevent the force applied to the material in the bucket by the attachment (12) during the operation from exceeding a threshold value at which the material can be leveled.

Description

Excavator

Technical Field

The present invention relates to an excavator.

Background

The excavator includes a traveling body called a crawler, an upper revolving body, a revolving device for revolving the upper revolving body relative to the traveling body, and an attachment attached to the upper revolving body. The attachment includes a boom, an arm, a bucket, and a boom cylinder, an arm cylinder, and a bucket cylinder for driving the boom, the arm, and the bucket. Each cylinder can be controlled by a lever operation of a driver (operator).

When the operator suddenly starts the boom shaft, the bucket shaft, or the revolving shaft in a state where the bucket contains materials such as sand, gravel, or the like, the materials are scattered from the bucket (this is called "sand overflow"). When the sand overflows, the work needs to be done again, which reduces the work efficiency.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open No. 2008-267760

Disclosure of Invention

Technical problem to be solved by the invention

However, in the past, when the sand spillage is suppressed, the rotation torque is suppressed from suddenly changing, the rotation acceleration is limited according to the setting of an operator, the rotation shaft is stopped slowly so as to reduce the impact of the attachment, and the like.

In the conventional art, the bucket angle is mainly controlled to be constant so that the bucket attitude is automatically maintained horizontal with respect to the ground, and the mechanical movement of the bucket is not taken into consideration.

The present invention has been made in view of the above problems, and an object of one embodiment of the present invention is to provide a shovel capable of suppressing an overflow of soil and sand.

Means for solving the technical problem

1. One aspect of the present invention relates to an excavator. The shovel is provided with: a crawler belt; an upper slewing body; a revolving device that rotates the upper revolving body relative to the crawler; an attachment having a boom, an arm, a bucket, a boom cylinder, an arm cylinder, and a bucket cylinder, and mounted on the upper slewing body; and a controller that restricts the operation of at least one of the attachment and the upper slewing body to prevent a force applied to the material in the bucket by the attachment during the operation from exceeding a threshold value at which the material can be stabilized.

According to this mode, the sand can be suppressed from overflowing by considering the force applied to the material in the attachment operation.

The controller may consider a resultant force of a force generated by the motion of the attachment and a force generated by the motion of the swing device. Therefore, the sand and soil overflow when the rotation movement and the bending and stretching movement of the attachment are carried out simultaneously can be inhibited.

The controller may suppress acceleration of at least one of the pivot axis, the swing arm axis, the bucket bar axis, and the bucket axis.

The controller can suppress the acceleration of all the axes of the revolving shaft, the boom shaft, the bucket shaft, and the bucket shaft.

The controller may preferentially suppress acceleration of the shaft dominating the direction of material spillage from the bucket.

The controller may inhibit a speed of at least one of the pivot axis, the boom axis, the dipper axis, and the dipper axis.

The controller can restrain the jerk of at least one of the rotating shaft, the movable arm shaft, the bucket rod shaft and the bucket shaft.

The threshold may correspond to a pose of the accessory.

2. One aspect of the present invention relates to an excavator. The shovel is provided with: a crawler belt; an upper slewing body; a revolving device that rotates the upper revolving body relative to the crawler; an attachment having a boom, an arm, a bucket, a boom cylinder, an arm cylinder, and a bucket cylinder, and mounted on the upper slewing body; and a controller that tilts the bucket in a direction in which a reference surface of the bucket is brought closer to a surface perpendicular to a direction of acceleration generated in the material in the bucket when the bucket moves.

Another form of the invention is also an excavator. The shovel is provided with: a crawler belt; an upper slewing body; a revolving device that rotates the upper revolving body relative to the crawler; an attachment having a boom, an arm, a bucket, a boom cylinder, an arm cylinder, and a bucket cylinder, and mounted on the upper slewing body; and a controller that tilts the bucket so that a normal force of the material in the bucket is increased while at least one of the swing device and the attachment is moving.

Another form of the invention is also an excavator. The shovel is provided with: a crawler belt; an upper slewing body; a revolving device that rotates the upper revolving body relative to the crawler; an attachment having a boom, an arm, a bucket, a boom cylinder, an arm cylinder, and a bucket cylinder, and mounted on the upper slewing body; and a controller that tilts the bucket so that a force acting on the material in the bucket in parallel with a reference surface of the bucket is reduced while at least one of the swing device and the attachment is moving.

In addition, when any combination of the above-described constituent elements, constituent elements or expressions of the present invention are replaced with each other in a method, an apparatus, a system or the like, the present invention is also effective as an aspect of the present invention.

Effects of the invention

According to the invention, the sand overflow can be inhibited.

Drawings

Fig. 1 is a perspective view showing an external appearance of a shovel which is an example of a construction machine according to an embodiment.

Fig. 2 is a diagram schematically showing a coordinate system of the excavator.

Fig. 3 is a block diagram of an example of the shovel according to embodiment 1.

Fig. 4 is a block diagram of an example of the shovel according to embodiment 1.

Fig. 5 is a block diagram of an example of the shovel according to embodiment 1.

Fig. 6 is a block diagram of an example of the shovel according to embodiment 1.

Fig. 7 is a diagram schematically showing the bucket and the material.

Fig. 8 is a diagram showing an operation of the shovel in the first usage mode 1.

Fig. 9 is a diagram showing an operation of the shovel in the 2 nd usage mode.

Fig. 10 is a block diagram of a controller.

Fig. 11 is a block diagram of an example of a shovel according to embodiment 2.

Fig. 12 is a diagram schematically showing a bucket and a material.

Fig. 13(a) and 13(b) are diagrams schematically showing bucket angle control by the controller.

Fig. 14(a) and 14(b) are views showing a 1 st use mode of the shovel effective in bucket angle control.

Fig. 15 is a diagram showing a 2 nd use mode of the excavator effective in bucket angle control.

Fig. 16 is a block diagram of a controller.

Fig. 17 is a block diagram of an electric system, a hydraulic system, and the like of the shovel according to modification 1.

Fig. 18 is a block diagram of an electric system, a hydraulic system, and the like of the shovel according to modification 2.

Detailed Description

The present invention will be described below with reference to the accompanying drawings according to preferred embodiments. The same or equivalent constituent elements, components, and processes shown in the respective drawings are denoted by the same reference numerals, and overlapping descriptions are appropriately omitted. The embodiments are not intended to limit the invention, but merely to exemplify the invention, and all the features or combinations thereof described in the embodiments do not necessarily limit the essence of the invention.

In the present specification, the term "state in which the component a and the component B are connected" includes not only a case in which the component a and the component B are physically and directly connected but also a case in which the component a and the component B are indirectly connected via another component without substantially affecting their electrical connection state or impairing the function or effect achieved by the combination thereof.

Fig. 1 is a perspective view showing an external appearance of a shovel 1 as an example of a construction machine according to an embodiment. The excavator 1 mainly includes a crawler belt (also referred to as a traveling mechanism) 2 and an upper revolving structure (hereinafter also simply referred to as a revolving structure) 4 rotatably mounted on an upper portion of the crawler belt 2 via a revolving device 3.

A boom 5, an arm 6 connected to a tip end of the boom 5 by a hinge (link), and a bucket 10 connected to a tip end of the arm 6 by a hinge are attached to the revolving structure 4. The bucket 10 is an apparatus for capturing a lifting material such as sand, steel, etc. The boom 5, the arm 6, and the bucket 10 are collectively referred to as an attachment 12, and are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, respectively. The revolving structure 4 is provided with a cab 4a for accommodating a position where the bucket 10 is operated, a driver performing the energizing operation and the releasing operation, and a power source such as an engine 11 for generating hydraulic pressure. The engine 11 is constituted by a diesel engine, for example.

Fig. 2 is a diagram schematically showing a coordinate system of the shovel 1. In the excavator 1, an angle coordinate θ representing the position of each of the boom 5, the arm 6, and the bucket 10 is defined₁～θ₃. As long as theta₁、θ₂And theta₃The positional relationship between the boom and the revolving unit 4, the positional relationship between the boom 5 and the arm 6, and the positional relationship between the arm 6 and the bucket 10 may be defined in a one-to-one manner. Will theta₁～θ₃Simply expressed as θ, to indicate the position (posture) of the entire attachment 12.

And phi denotes a turning angle of the turning device 3. R (theta)₁、θ₂、θ₃) Which is the distance between the origin O of the attachment 12 and the reference position X of the bucket 10. R is expressed as a function of the mechanism of the attachment 12 and can be based on the position information theta₁～θ₃And (4) calculating. Mixing R (theta)₁、θ₂、θ₃) Simply labeled R (θ). And, the origin of the attachment 12 and the shovelThe reference positions of the buckets 10 may be determined as appropriate.

(embodiment 1)

Fig. 3 to 6 are block diagrams of an electric system, a hydraulic system, and the like of the shovel 1 according to embodiment 1. In fig. 3 to 6, a system for transmitting power to the machine is indicated by a double line, a hydraulic system is indicated by a thick solid line, a steering system is indicated by a broken line, and an electric system is indicated by a thin solid line. Further, although the hydraulic shovel is described here, the present invention can also be applied to a hybrid shovel that uses an electric motor for rotation.

The engine 11 as a mechanical drive unit is connected to a main pump 14 and a pilot pump 15 as hydraulic pumps. A control valve 17 is connected to the main pump 14 via a high-pressure hydraulic line 16. In addition, sometimes the hydraulic circuit that supplies hydraulic pressure to the hydraulic actuators is provided as a dual system, in which case the main pump 14 includes 2 hydraulic pumps. In this specification, for the sake of easy understanding, a case where the main pump is a single system will be described.

The control valve 17 is a device for controlling the hydraulic system in the shovel 1. The control valve 17 is connected to traveling hydraulic motors 2A and 2B for driving the crawler belt 2 shown in fig. 1, and is also connected to a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 via a high-pressure hydraulic line, and the control valve 17 controls hydraulic pressure supplied to these cylinders in accordance with an operation input by the driver.

A turning hydraulic motor 21 for driving the turning device 3 is connected to the control valve 17. The swing hydraulic motor 21 is connected to the control valve 17 via a hydraulic circuit of a swing controller, but the hydraulic circuit of the swing controller is not shown in fig. 3 and the like and is simplified.

An operation device 26 (operation member) is connected to the pilot pump 15 via a pilot line 25. The operation device 26 is an operation device for operating the crawler 2, the swing device 3, the boom 5, the arm 6, and the bucket 10, and is operated by a driver. The control valve 17 is connected to the operation device 26 via a hydraulic line 27, and a pressure sensor 29 is connected to the operation device 26 via a hydraulic line 28.

The operation device 26 converts the hydraulic pressure (primary-side hydraulic pressure) supplied through the pilot line 25 into a hydraulic pressure (secondary-side hydraulic pressure) corresponding to the amount of operation by the driver, and outputs the hydraulic pressure. The hydraulic pressure on the secondary side output from the operation device 26 is supplied to the control valve 17 through a hydraulic line 27, and is detected by a pressure sensor 29. Although fig. 3 and the like show 1 hydraulic line 27, there are actually left and right traveling hydraulic motors and hydraulic lines for control command values for respective rotations.

The operation device 26 includes 3 input devices 26A to 26C. The input devices 26A to 26C are pedals or joysticks, and the input devices 26A to 26C are connected to the control valve 17 and the pressure sensor 29 via

hydraulic lines

27 and 28, respectively. The pressure sensor 29 is connected to a controller 30 that controls driving of the power system. In the present embodiment, the input device 26A functions as a swing lever, and the input device 26B functions as an attachment lever. The input device 26C is a walking stick or a pedal.

The controller 30 is a main control unit that performs drive control of the shovel. The controller 30 is configured by an arithmetic Processing device including a CPU (Central Processing Unit) and an internal memory, and is realized by the CPU executing a drive control program stored in the memory.

The sensor 530 detects position information θ of the accessory 23. Specifically, the position information θ includes angle coordinates θ indicating the positions of the boom 5, the arm 6, and the bucket 10₁～θ₃The detection value of (3). The sensor 530 can be constituted by a link angle sensor or a sensor that detects the displacement amount of the cylinder. Also, the position information may be angle information [ rad ]]Or angular velocity information [ rad/s ]]Or angular acceleration information [ rad/s²]。

The controller 30 restricts the operation of at least one of the attachment 12 and the upper slewing body 4 so as to prevent the force F applied to the material in the bucket 10 by the attachment 12 during the operation from exceeding a threshold value T at which the material can be leveled. The restriction control by the controller 30 will be described later.

Fig. 7 is a diagram schematically showing the bucket 10 and the material 40. In one mode of use, sand spillage occurs when the force F applied to the material 40 exceeds the maximum static friction μ N. Therefore, the threshold value T can be calculated in consideration of the static friction coefficient μ, the forward force N, and the mass m of the material 40.

Specifically, the threshold value can be calculated approximately by modeling the material and the bucket 10. The angle formed by the bucket 10 and the horizontal plane (ground) is δ. The normal force N of the bucket 10 in the rest state is mg × cos δ. And, in the direction x of the overflow of the charge 40, the component F of the gravity_GMg × sin δ works. Thus, the relation F_GThe condition that no sand overflow occurs is defined as < mu.N.

When the attachment 12 or the swing device 3 is operated, the force F caused by the operation of the attachment 12 or the swing device 3 is added to the weight component_||Is applied to the material 40. At this time, the relational expression F_||+F_GThe condition that no sand overflow occurs is defined as < mu.N. By modifying this, the following relational expression can be obtained, that is, the right side μ_N-F_GBecomes the threshold value T.

F_||＜μN-F_G

T＝μN-F_G＝μmg×cosδ-mg×sinδ

＝mg(μcosδ-sinδ)

That is, the threshold T is a function of the bucket angle δ, and therefore, when the bucket angle δ is in a range in which the bucket is likely to overflow, the threshold T is preferably set small. In addition, the positive force N is also changed because the attachment 12 or the swing device 3 is operated, but its influence is negligible.

The threshold value T may assume typical δ, μ, m at the design stage of the excavator 1 and use prescribed values calculated from these. Or can be set by the driver of the excavator 1.

Alternatively, the threshold value T may be adaptively calculated by describing an operation expression of the threshold value T in advance in a program (or hardware) executed by the controller 30. For example, the angle δ may be calculated according to the posture of the attachment 12 and the threshold value T may be calculated appropriately. And the mass m of the material 40 is measurable, the mass m can be reflected into the threshold value T.

In a higher model, the change in the positive force N caused by the action of the attachment 12 or the slewing device 3 can be taken into account.

It is empirically known that the ease of spillage varies depending on the shape of the material 40. It is therefore possible to detect the shape of the material or the like by a camera or the like and flexibly and adaptively change the threshold value T according to the shape.

It is preferable that the operation of the attachment 12 or the revolving unit 4 by the controller 30 is restricted only in a state where the material in the bucket 10 is carried, and not restricted, for example, in the soil unloading or the excavation. Since the overflow of the soil and sand does not cause a problem during the soil unloading and excavation operation, the reduction of the work efficiency can be prevented by releasing the restriction. In addition, when determining whether the soil is being removed or excavated, for example, the technique described in japanese patent application publication No. 2006-182504 can be employed.

Next, the operation restriction of the attachment 12 or the revolving unit 4 by the controller 30 will be described in association with a plurality of usage modes of the shovel 1.

Fig. 8 is a diagram showing an operation of the shovel 1 according to the first usage mode 1. Fig. 8 shows the slewing crane operation. During the slewing lifting action, the force F acting on the material 40 in the bucket_AThe formulae (1a) and (1b) are shown.

F_A＝m×α_A……(1a)

α_A＝(y₁₁+y₁₂+y₁₃+y₁₄)……(1b)

m: mass of material

α_A: acceleration of material

y₁₁: centrifugal force generated by the action of the attachment 12

y₁₂: centrifugal force generated by the action of the turning device 3

y₁₃: the force applied to the material 40 by the attachment 12 by the action of the slewing device 3

y₁₄: the force applied by the attachment 12 to the material 40 by the action of the attachment 12

That is, in this usage mode, the force y generated by the movement of the attachment 12 can be considered₁₁、y₁₄With a force y generated in association with the operation of the turning device 3₁₂、y₁₃Resultant force F of_A. The same considerations can be made with respect to the swing-down action.

Centrifugal force y₁₁Centrifugal force about origin O in the plane containing attachment 12, in y, to accompany displacement of the boom, stick, bucket axles₁₁＝R(θ)·(θ₁'+θ₂'+θ₃')²And (4) showing. "'" indicates the time derivative d/dt.

y₁₂Due to centrifugal force caused by rotation of the axis of rotation, e.g. in y₁₂＝R(θ)·φ'²And (4) showing.

y₁₃For forces applied to the material 40 by the attachment 12 by rotation of the shaft, e.g. in y₁₃R (θ) · Φ ″. "" indicates a second order differential in time (d/dt)²。

y₁₄The force applied by the attachment 12 to the material 40 in response to displacement of the arm, bucket or bucket axles, e.g. in y₁₄＝R(θ)·(θ₁”+θ₂”+θ₃") represents.

In addition, F_ABeing a three-dimensional vector, what acts on the soil overflow as shown in FIG. 7 is a component F parallel to the bucket 10_||. The gesture-operated parallel component F of the accessory 12 can therefore be taken into account_||. Or force F_AThe norm (absolute value) of (a) can both act on sand overflow and | F_A|≈F_||And (4) approximation.

The controller 30 also bases on the coordinates θ of each axis₁～θ₃And phi calculation force F_A. Force F, as described above_AViewed as θ₁～θ₃And a function of phi. Moreover, the threshold value which can make the material 40 stable in the rotary hoisting action is written as T_AAt this time, the controller 30 restricts the operation of at least one of the attachment 12 and the turning device 3 so as to satisfy the relational expression (2).

T_A＞F_A……(2)

Here, the threshold value T_ASince the friction force is mainly dominant, the approximation can be made in proportion to the mass of the material 40. If the proportionality coefficient is set as S_AThen threshold value T_ARepresented by formula (3).

T_A＝m×S_A……(3)

Relational expression (4) independent of mass m of material 40 is obtained from expressions (1) to (3). The controller 30 may limit the accelerations y of the plurality of axes to satisfy the relational expression (4)₁₁、y₁₂、y₁₃、y₁₄At least one of them may be used.

S_A＞(y₁₁+y₁₂+y₁₃+y₁₄)……(4)

Fig. 9 is a diagram showing an operation of the shovel 1 according to the 2 nd mode of use. Fig. 9 shows the lifting operation. In the lifting operation, the bucket 10 is pulled to the front while being lifted upward. In this lifting action, a force F acting on the material 40 in the bucket_BThe formulae (5a) and (5b) are shown.

F_B＝m×α_B……(5a)

α_B＝y₁₁……(5b)

y₁₁: centrifugal force generated by the action of the attachment 12

In addition, y may be considered in this usage pattern₁₄。

In this mode of use, the centrifugal force y₁₁In a direction in which the material 40 overflows from both sides of the bucket 10 toward the depth side of the arm 6.

The controller 30 also bases on the coordinates θ of each axis₁～θ₃Calculation force F_B. Moreover, the threshold value which can stabilize the material 40 in the lifting action is written as T_BAt this time, the controller 30 restricts the operation of at least one of the attachment 12 and the turning device 3 so as to satisfy the relational expression (6). Threshold value T_BCan be set to be equal to the threshold value T_AA different value.

T_B＞F_B……(6)

Threshold value T_BUsing a proportionality coefficient S_BRepresented by formula (7).

T_B＝m×S_B……(7)

From the expressions (5) to (7), a relational expression (8) independent of the mass m of the material 40 is obtained. The controller 30 may limit the acceleration y about the bucket shaft, the boom shaft, and the bucket shaft so as to satisfy the relation (8)₁₁、y₁₄One of them is sufficient.

S_B＞y₁₁……(8)

In the 1 st and 2 nd modes of use, the force F is suppressed_AOr F_BThe controller 30 can perform the following control.

Control 1. suppression of acceleration

The controller 30 can reduce the force F by limiting the acceleration (angular acceleration) of at least one axis_A、F_B。

Control 1a. for example, the controller 30 may maintain the relation (4) or (8) by suppressing the accelerations of all the axes. The suppression of the accelerations of all the axes can be achieved by (i) reducing the flow rate change of the pilot pressure, or (ii) limiting the amount of change (time rate of change) in the pump output torque, or the like. The flow rate change of the pilot pressure can be realized by adding an electromagnetic restrictor to the pilot line 25.

Specifically, in the shovel 1 of fig. 3, the flow rate adjustment valve 18 is provided in the path of the hydraulic line 27. The controller 30 can suppress the accelerations of all the axes by controlling the flow rate adjustment valve 18.

In the shovel 1 of fig. 4, the controller 30 controls the main pump 14, thereby suppressing the amount of change in the output torque of the main pump 14.

By suppressing the accelerations of all axes, y is directly suppressed₁₃And y₁₄The item (1). Then, since the speed decreases thereafter by the suppression of the acceleration, y₁₁、y₁₂The term (a) is also indirectly suppressed. As a result, force F_A、F_BThe sand overflow can be suppressed by reducing and satisfying the formulas (4) and (8). And can simplify control by suppressing all axes uniformly.

The controller 30 may control as follows: if S < alpha is obtained, the acceleration is suppressed, and if S < alpha is maintained, the acceleration is further suppressed. Alternatively, the controller 30 may suppress the acceleration according to the ratio K of S to α being α/S. For example, the acceleration may be suppressed in a predetermined range of 0 < K < 0.8 without being suppressed, and in a range of 0.8 < K. The larger K may be, the higher the degree of suppressing the acceleration. In order to satisfy the equations (4) and (8), there are various variables in the problem of how to reduce the acceleration, and the variables are also included in the scope of the present invention.

Control 1b or the controller 30 may limit the acceleration of several axes without inhibiting the acceleration of the other axes. E.g. about the bucket axis theta₃Sometimes to force y₁₄The impact is less significant than with other axes. At this time, θ may not be limited₃Acceleration of theta is limited₁、θ₂Phi, the 3 axes of acceleration. By appropriately selecting an axis that does not restrict the acceleration, it is possible to prevent a decrease in responsiveness and a deterioration in operational feeling.

Or the controller 30 may suppress only the acceleration of the revolution axis phi. In addition, this control cannot be confused with the conventional art. Heretofore, the force y generated by the motion of the attachment has not been considered₁₁、y₁₄。

Control 2. suppression of speed

The controller 30 can reduce the force F by limiting the speed (angular velocity) of at least one shaft_A、F_B。

Control 2a. controller 30 may maintain relation (2) by limiting the speed of all the shafts. The suppression of the speeds of all the shafts can be achieved by (i) reducing the output torque of the pump, (ii) reducing the pilot pressure, or (iii) reducing the rotation speed of the engine.

In the shovel 1 of fig. 4, the controller 30 controls the main pump 14 to reduce the output torque of the main pump 14, thereby limiting the speed.

In the excavator 1 of fig. 5, the proportional valve 19 is provided in the hydraulic line 27. The controller 30 can limit the speed by controlling the proportional valve 19 to reduce the pilot pressure.

In the shovel 1 of fig. 6, the controller 30 can limit the speed by reducing the rotation speed of the engine 11.

The controller 30 may control as follows: when S < alpha is obtained, the speeds of all axes are suppressed, and when S < F is maintained, the speeds are further suppressed. Alternatively, the controller 30 may also suppress the speed according to the ratio K of S to α being α/S. For example, the rate may be suppressed in a predetermined range of 0 < K < 0.8 without suppressing the rate, and in the case where the rate is 0.8 < K. The greater K may be, the higher the degree of suppression speed.

By thus suppressing the speeds of all the axes, the term y of the centrifugal force₁₁And y₁₂The term (1) is suppressed. As a result, force F_A、F_BThe formulas (4) and (8) are reduced and satisfied, so that the sand overflow can be inhibited. Further, the control can be simplified by suppressing all the axes uniformly.

Control 2b the controller 30 may limit the speed of several axes without inhibiting the speed of the other axes. By appropriately selecting an axis that does not restrict the acceleration, it is possible to prevent a decrease in responsiveness and a deterioration in operational feeling.

Control 3. suppression of acceleration and velocity

The controller 30 may adopt both the control of suppressing the acceleration and the control of suppressing the speed. At this time, y₁₁、y₁₂、y₁₃、y₁₄All items being constrained such that the force F_A、F_BAnd (4) descending. For example, (i) both the acceleration and the velocity of all axes, or (ii) both the acceleration and the velocity of selected ones of the axes, or (iii) both the acceleration of some of the axes and the velocity of other ones of the axes may be suppressed.

Control 4. suppression of jerk

The controller 30 can reduce the force F by limiting the jerk (jerk) of at least one axis_A、F_B. Suppression of jerk may be combined with suppression of acceleration and velocity.

In this way, control can be achieved in which the force F does not exceed the threshold value T by suppressing acceleration, velocity, and jerk.

Next, control of the plurality of axes will be described. The controller 30 may preferentially suppress acceleration, speed, or jerk of the shaft that dominates the direction of material 40 spilling from the bucket 10.

S＞K₁·y₁₁+K₂·y₁₂+K₃·y₁₃+K₄·y₁₄……(9)

K₁、K₂、K₃、K₄For each axis gain, the controller 30 will K₁、K₂、K₃、K₄The weighting is performed so that the overflow of the sand can be suppressed without spoiling the operational feeling.

The controller 30 can flexibly and adaptively change K according to the shape of the soil, the posture of the bucket, and the like₁、K₂、K₃、K₄. The ease of overflowing the sand and the direction in which the sand and the soil easily overflow may be different depending on the shape of the sand and the posture of the bucket. Where K is varied taking these factors into account₁、K₂、K₃、K₄Therefore, the sand overflow can be suppressed without damaging the operation feeling of the shaft irrelevant to the sand overflow.

Fig. 10 is a block diagram of the controller 30. The controller 30 includes a threshold acquisition unit 32, a force calculation unit 34, and a restriction unit 36. The controller 30 can be realized by a combination of hardware such as a CPU, a microcontroller, or a DSP (Digital Signal Processor) and a program, and thus the threshold value acquisition unit 32, the force calculation unit 34, and the restriction unit 36 are regarded as a part of the CPU or the DSP in terms of hardware.

The threshold value acquisition unit 32 acquires the threshold value T. The threshold value T may be calculated as described above, or may be a predetermined value. Or the threshold value T is obtained by multiplying a predetermined value by a variable coefficient corresponding to the bucket angle δ or the shape of the material 40. The threshold T may be represented by S with an acceleration dimension as above.

The force calculation unit 34 receives information θ indicating the position of the attachment 12₁～θ₃And information phi indicating the state of the turning device 3 and calculates the force F. The force F may be expressed in a having an acceleration dimension.

The limiting unit 36 limits the operation of at least one of the attachment 12 and the turning device 3 based on the relationship between the acceleration α and the threshold value S. As described above, the limiting unit 36 can limit the acceleration, the speed, and the jerk, and there may be various variables in the axis to be limited.

The above description has been made of embodiment 1. This embodiment is an example, and those skilled in the art will understand that various modifications are possible in combination of these various constituent elements and the respective processing procedures, and such modifications also fall within the scope of the present invention. Hereinafter, such a modification will be described.

(modification of embodiment 1)

The model shown in fig. 7 is merely an example of the determination of the threshold T, and the threshold T may be determined by another model.

In the use mode of the shovel 1 shown in fig. 8 and 9, the force F acting on the material 40_A、F_BThe formula (1) and (5) are not limited. For example, one item may be omitted and other items may be further considered.

(embodiment 2)

Fig. 11 is a block diagram of an electric system, a hydraulic system, and the like of the shovel 1 according to embodiment 2.

As will be described in detail later, the controller 30 prevents the sand from overflowing by controlling the inclination of the bucket 10. For example, if the control valve 17 is electronically controllable, the controller 30 may directly electrically drive the valves that control the bucket cylinder 9 or the

other cylinders

7, 8. The above is an overall block diagram of the shovel 1.

Next, a mechanism of sand overflow will be explained. Fig. 12 is a diagram schematically showing the bucket 10 and the material 40. In one mode of use, sand spillage is considered to occur when the force F applied to the material 40 exceeds a threshold value T corresponding to the maximum static friction μ N. Therefore, the threshold value T can be calculated by taking into account the static friction coefficient μ, the forward force N, and the mass m of the material 40.

Specifically, the threshold T can be approximated by modeling the material and the bucket 10. An angle (hereinafter referred to as a bucket angle) formed by the reference plane of the bucket 10 and the horizontal plane (ground) is δ. The reference surface 41 can be determined to be parallel to the bottom or upper surface of the bucket. The normal force N of the bucket 10 in the rest state is mg × cos δ. g represents the gravitational acceleration. And, in the direction x of the overflow 40, a component F of gravity_GAs mg × sin δ has effects. Thus, the relation F_GThe condition that no sand overflow occurs is defined as < mu.N. In the conventional bucket angle constant control, it is considered that F is made to approach δ to zero_GApproaching zero to increase the positive force N to prevent sand spillage.

By operating the attachment 12 or the slewing gear 3, in addition to gravityComponent F_GIn addition, there is a force F caused by the action of the attachment 12 or the slewing device 3_||Is applied to the material 40. At this time, the relational expression F_||+F_GThe condition that no sand overflow occurs is defined as < mu.N. Force F_||May include acceleration due to operation of the attachment 12, centrifugal acceleration, acceleration due to activation of the slewing device 3, centrifugal acceleration.

Next, control for preventing soil erosion of the shovel 1 according to the present embodiment will be described. Fig. 13(a) and 13(b) are diagrams schematically showing bucket angle control by the controller 30. The material 40 can be considered to be divided into an overflow upper portion 40a, a lower portion 40b housed in the bucket 10, and the lower portion 40b can be considered to be integral with the bucket 10.

Now, it is considered that the bucket 10 is accelerated at an acceleration α in the arrow direction in the figure, i.e., the ground horizontal direction (X-axis direction). In fig. 13, (a) to (c) show the magnitude of the acceleration. Fig. 13(a) shows control for keeping the bucket angle δ at 0 degree as in the conventional art. Assuming that the mass of the upper portion 40a is m, the normal force N is mg, and the maximum static friction force is μmg. The force that applies the acceleration α to the lower portion 40b in the arrow direction X is equal to the force that applies the acceleration α to the upper portion 40a in the direction opposite to the arrow direction X. Therefore, when the following relationship is established, that is

mα＞μmg

When the following relationship is established, the method

α＞μg……(1)

The upper portion 40a overflows in the opposite direction of the X-axis.

Fig. 13(b) shows bucket angle control by the controller 30 in the present embodiment. When accelerating the bucket 10 at the acceleration α, the controller 30 tilts the bucket 10 in a direction in which the reference surface 41 of the bucket 10 is close to the surface 42 perpendicular to the direction of the acceleration (X direction) generated in the material 40 when moving the bucket 10. Control of bucket angle δ may be via bucket axis θ alone₃The control of (2) may be performed in combination with the arm axis theta₁Bucket rod axis theta₂Is performed.

The upper part 40a is subjected to an acceleration a in the direction opposite to the arrow X, as in fig. 13(a)The force is applied with a gravitational acceleration g in the vertical direction. The normal force at this time is a component α of the acceleration α perpendicular to the reference surface 41_||And a component g of the gravitational acceleration g perpendicular to the reference plane 41_||To sum, i.e.

g×cosδ+α×sinδ

Therefore, the maximum static friction force is as follows:

μ×(g×cosδ+α×sinδ)。

on the other hand, the force sliding the upper portion 40a in the direction horizontal to the reference surface 41 becomes the component α of the acceleration α parallel to the reference surface 41_||And a component g of the gravitational acceleration g parallel to the reference plane 41_||To sum, i.e.

α×cosδ-g×sinδ

In addition, α_||And g_||Is the reverse direction.

Therefore, when the relational expression (2) is established, the upper portion 40a overflows in the X-axis direction or the opposite direction.

|α×cosδ-g×sinδ|＞μ×(g×cosδ+α×sinδ)……(2)

By comparing the relational expressions (1) and (2), the advantage of the bucket angle control according to the embodiment is clear. The left side of each of the relational expressions (1) and (2) is a force for causing the upper portion 40a to overflow, and δ is appropriately selected so that the following expressions are satisfied.

α＞|α×cosδ-g×sinδ|

On the other hand, when the maximum static friction force on the right side of each of the relational expressions (1) and (2) is compared, δ is appropriately selected so that the following expression holds, that is, δ is selected so that

μg＜μ×(g×cosδ+α×sinδ)

That is, when the relational expressions (1) and (2) are compared, it is found that the relational expression (2) is hardly satisfied.

The above is the principle of bucket angle control by the controller 30. As described above, according to the shovel 1 of the embodiment, when the bucket 10 is moved, the bucket 10 is tilted in a direction in which the reference surface 41 thereof is close to the surface 42 perpendicular to the direction of acceleration (X direction) generated in the material 40, and thereby the overflow of the soil and sand can be suppressed.

As described above, when the right sides of the respective relational expressions (1) and (2) are compared, the right side of the relational expression (2) is larger. In other words, in another point of view, the controller 30 may control the bucket 10 to tilt such that the maximum static friction force against the material 40 (the upper portion 40a) is increased, in other words, the normal force is increased, when at least one of the swing device 3 and the attachment 12 is moved (i.e., the bucket 10 is moving).

As described above, when the left sides of the relational expressions (1) and (2) are compared, the left side of the relational expression (2) is smaller. In other words, in another point of view, the controller 30 may control the tilt of the bucket 10 so that the force acting on the material 40 (the upper portion 40a) in parallel with the reference surface is reduced when at least one of the swing device 3 and the attachment 12 is moved.

The bucket angle control by the controller 30 is performed only in a state where the material 40 in the bucket 10 is carried, and it is preferable not to perform the bucket angle control, for example, during soil unloading or excavation. Since the overflow of the soil and sand does not cause a problem during the soil unloading and excavation operation, the restriction is released, and the reduction of the work efficiency can be prevented. In addition, when determining whether the soil is being removed or excavated, for example, the technique described in japanese patent application publication No. 2006-182504 can be employed.

Fig. 14(a) and 14(b) are diagrams showing a 1 st use mode of the shovel 1 in which bucket angle control is effective. The mode 1 of use shows a turning operation in which the attachment 12 is fixed and the turning device 3 is turned. Centrifugal acceleration R phi 'during the turning motion'²Acts on the material 40 in conjunction with the rotational acceleration R phi ".

Since the bucket 10 moves in a plane including the boom 5 and the arm 6, it is not possible to tilt in a direction opposite to the swing acceleration r Φ ″. Therefore, the controller 30 may tilt the reference surface of the bucket in a direction close to the vertical plane of the acceleration in the plane, taking into account the force acting in the plane including the boom 5 and the arm 6, among the forces acting on the material 40. Specifically, during the turning operation, the controller 30 brings the bucket 10 closer to the centrifugal acceleration R + to the reference surface 41 thereof'²Is inclined in the direction of the vertical plane 42.

FIG. 15 is a drawing showingFig. 2 shows an operation mode of the excavator 1 effective in bucket angle control. The use 2 shows the action of lifting (or lowering) the material 40 by the attachment 12 with the rotating shaft phi fixed. Acceleration R theta ' and centrifugal acceleration R theta ' in hoisting action '²Acts on the material 40. The controller 30 brings the bucket 10 to approach the acceleration R θ ' and the centrifugal force acceleration R θ ' with the reference surface 41 thereof '²The vertical surface of either one of the above-mentioned members is inclined.

Or the controller 30 may relate the acceleration R θ 'to the centrifugal force acceleration R θ'²Vector synthesis is performed to tilt the bucket 10 so that the reference surface 41 thereof approaches a vertical surface of the synthesized acceleration.

The bucket angle control according to the embodiment is also effective in the combined swing-up operation (swing-down) operation, in addition to the use modes of fig. 14 and 15. In the slewing hoisting operation, acceleration R theta 'and centrifugal force acceleration R theta'²And centrifugal acceleration R phi'²The rotational acceleration R phi acts on the material 40. The controller 30 can be controlled according to the acceleration R theta 'and the centrifugal force acceleration R theta'²And centrifugal acceleration R phi'²Any one or a combination of several of them performs bucket angle control.

Fig. 16 is a block diagram of the controller 30. The controller 30 of fig. 16 includes an acceleration direction acquisition unit 32, a bucket angle calculation unit 34, and a reverse kinematics calculation unit 36. The controller 30 can be realized by a combination of hardware such as a CPU, a microcontroller, or a DSP (digital Signal processor) and a program, and thus the acceleration direction obtaining unit 32 and the bucket angle calculating unit 34 are regarded as a part of the CPU or the DSP in terms of hardware.

The acceleration direction acquiring unit 32 acquires the direction of acceleration generated in the material 40 in the bucket 10 when the bucket 10 is moved. The acceleration direction obtaining part 32 may obtain the position information θ₁～θ₃And phi (or velocity information) calculating the acceleration direction. Or may maintain the position information theta₁～θ₃And a distribution map (table) in which phi (or velocity information) is associated with the acceleration direction, and the acceleration direction is acquired by referring to the table. Distribution diagram for each use mode (lifting action, rotation)Motion, rotary hoisting motion).

The bucket angle calculation unit 34 determines the bucket angle δ by calculation or referring to a list so as to approach the vertical plane of the acceleration direction obtained by the acceleration direction acquisition unit 32. The inverse kinematics calculation unit 36 calculates a link angle θ at which a bucket angle δ can be obtained₁～θ₃The instruction value of (2).

In fig. 16, the bucket angle δ is determined by two stages of signal processing by the acceleration direction acquisition unit 32 and the bucket angle calculation unit 34, but the present invention is not limited to this. For example, the position information θ may be prepared in advance₁～θ₃And a map (table) in which phi (or speed information) is directly associated with the bucket angle δ, and the bucket angle δ is determined by referring to the table. In this case, the profile may be prepared for each usage pattern (lifting operation, turning lifting operation).

The bucket angle δ may be changed adaptively according to the magnitude of the acceleration and the type of operation of the shovel 1. Alternatively, a predetermined constant value may be set for each shovel operation, and when the shovel operation is determined, the corresponding constant value may be used.

The bucket angle control according to the embodiment is also effective when the bucket is decelerated.

Next, another embodiment of bucket control by the controller 30 will be described. Fig. 17 is a block diagram of an electric system, a hydraulic system, and the like of the shovel according to modification 1. In order to control the bucket angle, the shovel 1 is provided with a switching valve 18 and a proportional valve 19. In the event that the control valve 17 is unable to electrically control the bucket shaft or other shaft, the controller 30 may control the switching valve 18 and the proportional valve 19, thereby controlling the pressure to the control valve 17 to control the bucket angle.

Fig. 18 is a block diagram of an electric system, a hydraulic system, and the like of the shovel according to modification 2. The shovel 1 includes a flow rate adjustment valve 20 instead of the switching valve 18 and the proportional valve 19 shown in fig. 17. The controller 30 may control the flow regulating valve 20 to vary the flow of the pressurized oil supplied to the control valve 17 to control the bucket angle.

The present invention has been described in terms of several embodiments and specific terms, but the embodiments are merely illustrative of the principles and applications of the present invention, and various modifications and permissible arrangements of the embodiments may be made without departing from the scope of the inventive concept defined in the appended claims.

Description of the symbols

1-an excavator, 2-a crawler, 2A, 2B-a traveling hydraulic motor, 3-a turning device, 4-a turning body, 4 a-a cab, 5-a boom, 6-an arm, 7-a boom cylinder, 8-an arm cylinder, 9-a bucket cylinder, 10-a bucket, 11-an engine, 12-an attachment, 14-a main pump, 15-a pilot pump, 16-a high-pressure hydraulic line, 17-a control valve, 18-a switching valve, 19-a proportional valve, 20-a flow regulating valve, 21-a turning hydraulic motor, 25-a pilot line, 26-an operating device, 27, 28-a hydraulic line, 29-a pressure sensor, 30-a controller, 32-an acceleration direction acquiring section, 34-a bucket angle calculating section, 36-inverse kinematics calculation, 40-material, 40 a-upper part, 40 b-lower part, 530-sensor.

Industrial applicability

The present invention can be applied to industrial locomotives.

Claims

1. A shovel is characterized by comprising:

a crawler belt;

an upper slewing body;

a slewing device that causes the upper slewing body to rotate relative to the crawler;

an attachment having a boom, an arm, a bucket, a boom cylinder, an arm cylinder, and a bucket cylinder, and attached to the upper slewing body; and

and a controller that restricts an operation of at least one of the attachment and the upper slewing body so as to prevent a force generated in the material in the bucket by the operation of the attachment from exceeding a threshold value calculated to stabilize the material.

2. The shovel of claim 1,

the controller takes into account a resultant of a force generated by the motion of the attachment and a force generated by the motion of the swing device.

3. The shovel of claim 1 or 2,

the controller suppresses acceleration of at least one of the revolving shaft, the boom shaft, the bucket rod shaft, and the bucket shaft.

4. The shovel of claim 3,

the controller suppresses acceleration of all the axes of the revolving shaft, the boom shaft, the bucket shaft, and the bucket shaft.

5. The shovel of claim 3,

the controller preferentially suppresses acceleration of the shaft that dominates the direction of material spillage from the bucket.

6. The shovel of claim 1 or 2,

the controller inhibits the speed of at least one of the revolving shaft, the movable arm shaft, the bucket rod shaft and the bucket shaft.

7. The shovel of claim 1 or 2,

the controller inhibits jerkiness of at least one of the rotating shaft, the movable arm shaft, the bucket rod shaft and the bucket shaft.

8. The shovel of claim 1 or 2,

the threshold corresponds to a pose of the accessory.

9. A shovel is characterized by comprising:

a crawler belt;

an upper slewing body;

and a controller that tilts the bucket in a direction in which a reference surface of the bucket is brought closer to a surface perpendicular to an acceleration direction of movement of the material generated in the material in the bucket when the bucket is moved.

10. A shovel is characterized by comprising:

a crawler belt;

an upper slewing body;

and a controller configured to tilt the bucket so as to increase a positive force of the material generated by movement of the material in the bucket when at least one of the swing device and the attachment is movable.

11. A shovel is characterized by comprising:

a crawler belt;

an upper slewing body;

and a controller configured to tilt the bucket so that a force acting parallel to a reference surface of the bucket among forces acting on the material due to movement of the material in the bucket is reduced when at least one of the swing device and the attachment is movable.