JPH0565723A - Operation controller - Google Patents

Abstract

PURPOSE:To facilitate an operation by detecting the posture of a bucket and the action force against the bucket during the work motion by the bucket and controlling a rotary drive or a lifting drive in accordance with the magnitude of working moment. CONSTITUTION:A cylinder pressure sensor 14 is provided at the bucket cylinder of a wheel loader equipped with a bucket to detect the cylinder pressure for the actuation force rotating the bucket. And further, a boom angle sensor 16 is provided to detect the rotary angle of the boom. And a bucket angle sensor 18 is provided to check the rotary angle of the bucket. Next, the rotary angle detected by the boom angle sensor 16 and the bucket angle sensor 18 is used to calculate the excavation moment by means of the operation means 21 of bucket posture and the operation means 22 of the moment. Next, the moment calculated by the moment operation means 22 is output to the hydraulic controller 31 of bucket cylinder by the control operation 23 of bucket rotation to calculate the instruction signal. And hence, the cost can be remarkably reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for automatically controlling the drive of a bucket in a working machine such as an excavating machine or a loading machine having a bucket.

[0002]

2. Description of the Related Art Generally, in a working apparatus having a bucket such as a wheel loader or a hydraulic excavator, the operation of the bucket is currently performed manually based on the operator's feeling. The following Table 1 shows an outline of typical driving operations performed in the hydraulic excavator.

[0003]

[Table 1]

However, the operation of the bucket by such a manual operation requires a considerable amount of skill and imposes a heavy burden on the operator. On the other hand, even if a skilled operator operates, the operation is not always efficient. Not exclusively.
Therefore, the development of a device for automatically controlling the driving of the bucket is in progress.

Conventionally, a method of controlling the work locus of the bucket has been proposed as a method of performing such automatic control of bucket drive. For example, JP-A-60-21
Japanese Patent No. 9332 discloses that the trajectory of the bucket blade edge according to the work is determined in advance and the bucket is driven along the trajectory.

[0006]

The above-mentioned device for performing so-called excavation trajectory control has the following problems.

(1) Generally, in normal excavation, there is a point where the excavation force becomes temporarily excessive, but the above point cannot be avoided by simply controlling the excavation trajectory. Therefore, at the above points, the bucket or the like may be adversely affected in terms of strength, and the bucket operating speed may be reduced.

(2) The excavation locus of the bucket naturally varies depending on the object to be excavated and the shape of the ground, but the excavation locus control method cannot flexibly cope with this.

(3) In order to perform excavation trajectory control, it is necessary to provide sensors such as potentiometers and encoders in all the rotating parts, and it is necessary to detect the acting forces of all actuators. It requires a sensor, leading to higher costs.

(4) Excavation trajectory control requires a large-capacity CPU because complicated calculations must be performed, which leads to an increase in cost.

In view of such circumstances, it is an object of the present invention to provide a work control device which has a simple and low-cost structure and can perform an appropriate bucket drive control in accordance with an actual operating condition. To do.

[0012]

In a work machine having a bucket as described above, the point at which the excavation resistance increases and the point at which the moment acting on the bucket increases become substantially the same, and normal excavation is performed. In this state, the excavation resistance increases as the bucket bites into the object to be excavated. Therefore, the judgment items of the bucket operation as shown in Table 1 can be replaced with the magnitude of the moment acting on the bucket.

The present invention has been made paying attention to such a point, and includes a bucket, a bucket support member that rotatably supports the bucket, and a main body that rotatably supports the bucket support member. In a working machine provided with bucket rotation driving means for rotating the bucket with respect to a bucket support member, and bucket lifting drive means for lifting and lowering the bucket with respect to a work surface by rotating the bucket support member with respect to a main body. A bucket attitude detecting means for detecting the attitude of the bucket, an acting force detecting means for detecting an acting force for rotating the bucket, and a moment for momentarily calculating a working moment around the rotation axis of the bucket from the bucket attitude and acting force. A calculation means and a bucket for controlling bucket rotation drive based on the calculated work moment. And preparative rotation control means, in which a bucket elevator control means for controlling the bucket elevator driven based on the working moment.

Furthermore, in addition to the moment calculation means,
Moment time change amount calculation means for calculating the time change amount of the work moment is provided, and the bucket rotation control means is configured to control the bucket rotation drive based on the work moment and the time change amount thereof. By configuring the bucket ascending / descending control means so as to control the bucket ascending / descending drive based on the amount of change with time, a more excellent effect as described below can be obtained (claim 2).

[0015]

According to the first aspect of the present invention, the bucket attitude and the acting force on the bucket are detected during the work operation by the bucket, and the work moment, that is, the rotation about the rotation axis of the bucket, is detected from these values. Is momentarily calculated, and based on the magnitude of the work moment, the rotation of the bucket and the drive for raising and lowering the excavation surface are controlled.

Further, according to the apparatus of the second aspect, in addition to the work moment, the time change amount thereof is calculated,
Based on the both values, the bucket drive control is executed in consideration of the tendency of increase and decrease of the work moment.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS.

In this embodiment, the present invention is applied to a wheel loader as shown in FIG. The wheel loader includes a bucket 1, and the bucket 1 is rotatably attached to the tip of a boom (bucket support member) 2 so as to be rotatable about a shaft 9. The base end of the boom 2 is pivotally attached to the main body 8 so as to be rotatable about an axis 12, and the boom 2 is a boom cylinder (bucket lifting drive means).
The bucket 1 is driven to rotate by the expansion and contraction of 6, and the bucket 1 is moved up and down with respect to the excavation surface G during the excavation by the drive of the boom 2.

An intermediate portion of the arm 3 is pivotally attached to an intermediate portion of the boom 2 so as to be rotatable about an axis 11. The upper end of the arm 3 is a bucket cylinder (bucket rotation drive means).
5, the lower end of the arm 3 is connected to a position different from the shaft 9 in the bucket 1 via the link 4 and the shaft 10, and the arm 3 is expanded and contracted by the expansion and contraction of the bucket cylinder 5. The bucket 1 is rotated, and the bucket 1 is driven to rotate around the shaft 9 accordingly.

The bucket cylinder 5 is provided with a cylinder pressure sensor (acting force detecting means) 14 as shown in FIG. 1, and the cylinder pressure sensor 14 acts as an acting force for rotating the bucket 1 on the bucket cylinder 5. Cylinder pressure is detected. Also, the shaft 1
A boom angle sensor (constitutes bucket attitude detecting means) 16 for detecting a rotation angle of the boom 2 with respect to the main body 8
The shaft 9 is provided with a bucket angle sensor (constituting bucket attitude detecting means) 18 for detecting the rotation angle of the bucket 1 with respect to the boom 2.

The detection signals of these sensors 14, 16 and 18 are input to a controller 20 as shown in FIG.
Based on these detection signals, the controller 20 controls the rotation drive and the elevation drive of the bucket 1.

Specifically, the controller 20 includes a bucket attitude calculating means 21, a moment calculating means 22, a bucket rotation control calculating portion 23, and a bucket elevating control calculating portion 24.

The bucket attitude calculating means (constituting the bucket attitude detecting means) 21 is based on the respective rotation angles detected by the boom angle sensor 16 and the bucket angle sensor 18, ie, the bucket attitude, that is, the ground angle of the bucket 1 and the above-mentioned action. The radius of moment around the force axis 9 is calculated. During the excavation work, the moment calculation means 22 is based on the bucket posture calculated by the bucket posture calculation means 21 and the acting force detected by the cylinder pressure sensor 14,
The excavating moment around the shaft 9 acting on the bucket 1 is calculated.

The bucket rotation control calculation unit 23 calculates a command signal to be output to the bucket cylinder hydraulic pressure control unit 31 based on the magnitude of the excavation moment calculated by the moment calculation unit 22, and the bucket cylinder 5 is controlled by this command signal. Expansion / contraction control, that is, bucket rotation control about the axis 9 is executed. Similarly, the bucket ascending / descending control calculation unit 24 calculates a command signal to be output to the boom cylinder hydraulic pressure control unit 32 based on the magnitude of the excavation moment, and the expansion / contraction control of the boom cylinder 6, that is, the excavation surface G, is performed by the command signal. Executes bucket lift control.

Next, the control content will be described with reference to the graph of FIG.

In this control, the basic characteristics during excavation by the bucket 1 are used. First, the operation of the bucket 1 is decomposed into bucket rotation, bucket up and down with respect to the excavation surface G (that is, rotation of the boom 2), and forward / backward movement of the bucket 1, and the bucket rotation moves toward the scooping side around the shaft 9. Rotation (counterclockwise rotation in Fig. 2; retract)
And the rotation to the discharge side (clockwise rotation in FIG. 2; dump). Of these, the forward movement of the bucket 1 is performed by the forward movement of the entire main body 8, so drive control of the boom 2 and the bucket 1 is performed. Has no direct relationship with. Further, it is not necessary to take the backward movement of the bucket 1 into consideration during excavation.

Therefore, assuming that the basic operation at the time of excavation is the bucket forward movement, the following matters can be said regarding the relationship between the other operations, that is, the bucket rotating operation and the bucket ascending / descending operation, and the state of the bucket 1. (a) Retracting the bucket reduces the excavation moment. That is, the resistance that the bucket 1 receives from the excavation target (arrow R in FIG. 2) decreases. On the other hand, by dumping or neutralizing the bucket 1, the bite of the bucket 1 into the excavation object increases, and the excavation moment increases. (b) When the bucket 1 is lowered with respect to the excavation surface G, the bite of the bucket 1 into the excavation object increases. vice versa,
When the bucket 1 is lifted, the bucket 1 moves in a direction in which it does not bite into the excavation target.

Therefore, in this embodiment, an appropriate limit value is set for the excavating moment calculated by the moment calculating means 22 shown in FIG. 1, and based on the comparison between this control value and the calculated value calculated moment by moment. In addition to the bucket drive control, a series of operations from the start to the end of excavation by the bucket 1 are divided into the following three periods, and the control according to each period is performed.

1) First Step (Initial Excavation) First, in the initial stage of excavation, it is necessary to stop the rotation of the bucket 1 in order to sufficiently dig it into the object to be excavated. Therefore, the bucket rotation command is not issued until the excavation moment reaches the limit value M-1 shown in FIG.
When the excavation moment reaches the limit value M-1, the second
Try to move to step. On the other hand, when the bucket 1 is moved up and down, the bucket 1 may be lifted even in the initial stage of excavation. In this embodiment, however, in consideration of this point, the excavation moment is limited to the limit value WM-4 (≤M-
When 1) is exceeded, a bucket up command (that is, rotation of the boom 2 in the counterclockwise direction in FIG. 2) is issued.

2) Second Step (Middle Excavation) After the excavation moment reaches the limit value M-1, the second step is performed.
Go to step, and control both bucket rotation and bucket ascent / descent according to the excavation moment. In this embodiment, two kinds of limit values WM-2 and WM-3 (0 <WM-3 <WM-2) are set for the bucket rotation drive, and one kind of limit value WM-5 is set for the bucket lifting drive.
(<0) is set and the following control is performed. (a) When the excavation moment is higher than the limit value WM-2, the excavation resistance is high, and it is considered that the bucket is fully engaged, so the bucket 1 is retracted. (b) Limit value WM when excavation moment is limit value WM-3 or more
In the case of −2 or less, the bucket 1 is held in a neutral state or dumped in order to further dig into the bucket 1.
In this embodiment, the bucket 1 is positively dumped instead of being held neutral, and so-called rocking excavation (heavy excavation), in which dumping and retracting are alternately repeated, is performed. (c) If the excavation moment is lower than the limit value WM-2, it is considered that abnormal excavation has occurred, so the bucket 1 is retracted to prevent the vehicle body 8 from rising. (d) When the excavation moment is larger than the limit value WM-5, the bucket ascent / descent is kept neutral, but when the excavation moment is smaller than the limit value WM-5 (in this case, the excavation moment is always negative). In this case, it is assumed that the excavation is abnormal, and the bucket 1 is lifted from the excavation surface G so that the vehicle body 8 does not float up. Therefore, when the limit value WM-5 is set to a small value, the boom 2 hardly moves and only the bucket rotation is performed, and when the limit value WM-5 is set to a sufficiently large value, the bucket 1 is set to a large value. Excavation surface G
The excavation form will be increased while rising. By executing the control based on such an excavation moment, the bucket 1 will automatically excavate a point where the excavation resistance becomes excessive and perform smooth excavation.

3) Third Step (Late excavation) As the excavation proceeds, the bucket 1 is filled with the excavated material, while the bucket rotation angle increases and the bottom surface of the bucket 1 is not the cutting edge but the object. They will come into contact with them, and it will be impossible to expect more effective excavation. Therefore, after the bucket rotation angle reaches the predetermined limit value A-1, the second step is ended and the process proceeds to the third step, the control by the excavation moment is stopped, and the bucket rotation angle is limited to the limit value A-2 ( > Bucket 1 is retracted until it reaches> A-1), and the excavation operation is terminated when this limit value A-2 is reached.

According to such a device, in particular the bucket 1
In the second step, which requires precise control, the control based on the magnitude of the excavation moment makes it possible to perform an accurate bucket operation in accordance with the actual operating state. That is, unlike the conventional method of controlling the excavation locus, it is possible to flexibly cope with any ground shape or object to be excavated, and perform bucket control suitable for this, and to prevent the excavation resistance of the bucket 1 from being excessive. Good excavation can be realized while avoiding the occurrence of the burrow.

FIG. 4 shows the time changes of the bucket rotation angle, the excavation resistance, and the moment due to the excavation resistance (excavation moment) when the bucket operation is performed based on the driver's sense as in the conventional case, respectively. 42 and 43, and FIG. 5 shows the changes over time of the bucket rotation angle, the excavation resistance, and the excavation moment under the control of the apparatus shown in the above-described embodiment, with lines 51, 52, and 53, respectively. It is a thing. As is clear from a comparison between the two graphs, according to the device of the present embodiment, the excavation resistance and excavation moment that act on the bucket 1 during excavation are distributed over the entire region, as compared with the conventional case where excavation is performed manually. The value can be suppressed to a low value, the strength load on the bucket 1 can be reduced, and efficient excavation can be performed.

Next, a second embodiment will be described. here,
An example in which the present invention is applied to a hydraulic excavator (backhoe) as shown in FIG. 6 will be shown. Like the wheel loader, this backhoe also includes a bucket 1, a boom (constituting a bucket supporting member) 2, an arm 3 (constituting a bucket supporting member) 3, a link 4, a bucket cylinder 5, a boom cylinder 6, a main body 8, and a shaft. Although the arm 3 is provided with the arms 9 and 10, the base end of the arm 3 is connected to the tip of the boom 2 via a shaft 11.
It is designed to be rotated with respect to. The bucket 1 is mounted on the tip of the arm 3 and is connected to a bucket cylinder 5 attached to the arm 3 via a link 4 and a shaft 10. It is designed to be rotated around nine.

Even in such a backhoe, there is no great difference from the wheel loader except that the bucket 1 is moved by the arm pulling operation, and therefore, the first step (initial stage of excavation) and the third step (shown in the first embodiment). The same control may be performed in the latter stage of excavation. The same applies to the second step (middle drilling), but this second step
In the step, better excavation can be realized by executing the control as shown in FIG. 7, for example. That is, one type of limit value HM-5 for bucket rotation drive
(> 0) is set, and two types of limit values HM-2 and HM-3 (0 <HM-3 <HM-2) for the bucket ascending / descending drive.
And set the following control. (a) When the excavation moment is higher than the limit value HM-5, it is considered that the bucket 1 is fully engaged, so the bucket 1 is retracted. (b) If the excavation moment is less than the limit value HM-5,
The bucket 1 is held neutral or dumped in order to make it more bite. In the illustrated example, bucket 1
Is kept neutral. (c) When the excavation moment is larger than the limit value HM-2, it is considered that the bucket 1 is sufficiently engaged and the excavation resistance is large. Therefore, the rotation of the boom 2 causes the bucket 1 to move to the excavation surface G. Raise against. (d) Limit value HM when excavation moment is limit value HM-3 or more
In the case of −2 or less, it is considered that good excavation is performed, and therefore, neutrality is maintained for bucket lifting. (e) Excavation moment is below the limit value HM-3 and HM-4
In the case of (0 in the example in the figure) or more, the boom 1 is rotated and the bucket 1 is lowered in order to make the bucket 1 bite more into the object to be excavated. (f) Excavation moment is less than HM-4 (negative value in the example)
If it is, it is considered that abnormal excavation has occurred, so the bucket 1 is raised as in the case of (a).

By executing such control, the rotation angle of the excavating blade of the bucket 1 and the height of the bucket pin (that is, the shaft 9 which is the rotation axis of the bucket 1) are as shown in the middle and lower stages of FIG. become. The region indicated by a dotted line in the middle graph of FIG. 7 is a region in which the excavating blade angle of the bucket 1 naturally changes due to the drive of the boom 2 and the arm 3 even though the bucket rotation drive is not performed. ..

This embodiment is also applicable to other hydraulic excavators, for example, a loading excavator as shown in FIG.

Next, a third embodiment will be described. In each of the above-mentioned embodiments, a plurality of limit values are set for the excavation moment, and the bucket drive control is performed in the second step based on the comparison between the limit values and the excavation moment calculated from moment to moment. In the embodiment, the fuzzy control is applied to the bucket drive control in the second step. That is, a memory storing fuzzy rules and membership functions is connected to the bucket rotation control calculation unit 23 and the bucket lift control calculation unit 24 shown in FIG. 1, and the output value of the bucket cylinder drive command signal and the boom cylinder drive command are calculated by fuzzy calculation. In the figure, the output values of signals are calculated.

In this embodiment, the work machine to be controlled is a wheel loader as in the first embodiment, and the excavation method is bucket swing excavation in which dump and retract are alternately repeated.

The membership functions of each variable in the fuzzy control are shown in FIGS. 9 to 12, and the relation between the antecedent part and the consequent part, that is, the rules are summarized in Table 2 below. Table 3 shows a comparison between the main rules and the actual operation contents of the operator.

[0041]

[Table 2]

[0042]

[Table 3]

Among the variables shown here, Mn is a value obtained by normalizing the excavation moment calculated by the moment calculating means 22 for fuzzy control, and -1 to + with the reference value as 0.
It is a value set in the range of 1. Further, SBMU indicates an output value of a command signal for a bucket raising operation and SBK indicates a bucket retract operation and a bucket dump operation, respectively. When SBK is a positive value, it is a retract operation command, and when it is negative, it is a dump operation command. Means that.

As shown in Table 2, in a region where the excavation moment is above the reference value, the bucket retract operation is executed at a speed corresponding to the magnitude, and in a region below the reference value, the dump operation is executed. However, when the excavation moment is abnormally low, the bucket retract operation is executed.
Further, the bucket raising operation is executed centering on a region where the excavation moment is slightly lower than the reference value.

By executing such fuzzy control, it becomes possible to realize more precise bucket control according to the actual excavation state.

In this embodiment, the case of bucket swing excavation (heavy excavation) is shown. On the other hand, in the case of performing bucket ordinary excavation, that is, excavation operation in which bucket retract and neutral retention are repeated, Since the bucket dump operation command is unnecessary, it is only necessary to introduce a rule that sets SBK to ZO when the excavation moment is NM or NS. That is, in this case, for example, the rules shown in Tables 4 and 5 below may be set.

[0047]

[Table 4]

[0048]

[Table 5]

Such fuzzy control is carried out by the above-mentioned FIG.
It goes without saying that it can be effectively applied to the hydraulic excavator shown in.

Next, a fourth embodiment will be described with reference to FIGS.

As shown in FIG. 12, the apparatus shown in this embodiment includes a moment calculation means 22 for calculating the excavation moment from moment to moment, and a moment time change amount calculation means 25 for calculating the time variation of the excavation moment. In addition, fuzzy control is performed on the rotation and the elevation of the bucket 1 based on both the current excavation moment and the amount of change over time. The moment time change amount computing means 25 computes the difference between the excavation moment computed value currently fetched and the excavation moment computed value fetched in the previous computation, and divides this by the sampling cycle of the excavation moment value to obtain the moment. It is configured to output as a time change amount. In the present invention, regardless of the calculation procedure of the moment time change amount, for example, a plurality of calculation values calculated in the past may be sampled and the average thereof may be taken.

In this embodiment, the case where normal excavation is carried out in the backhoe shown in FIG. 6 is shown, and the variables used are the values Mn, SBK, SBM shown in the above embodiment.
In addition to U, the normalized moment change amount ΔM and the arm pull signal output value SAME are introduced. 13 and 14 show the membership functions of these variables, Table 6 shows the rules for the arm pulling signal output value SAME, Table 7 shows the rules for the bucket rotation operation signal output value SBK, and the boom lifting operation signal output. Table 8 shows the rules for the value SBMU, and FIG. 15 shows specific control operations.

[0053]

[Table 6]

[0054]

[Table 7]

[0055]

[Table 8]

In Tables 6 to 8, the conditions regarding the excavation moment standard value Mn and the moment time change amount ΔM are connected by and in the antecedent part. For example, the upper left region of Table 6 is If Mn = NB and ΔM = NB Then SAME = ZO.

Regarding the arm pulling operation, as shown in Table 6, when the excavating moment standard value Mn is close to the reference value and the moment time change amount ΔM is close to 0, the arm pulling operation, that is, the bucket advancing operation is performed. Although actively performed, the arm pulling speed is decreased as the excavation moment standard value Mn becomes farther from the standard value. Even if the excavation moment standard value Mn is close to the reference value, if the moment time change amount ΔM is large in absolute value, the moment value is likely to be far from the reference value in the future. The speed is reduced. further,
When the excavation moment standard value Mn is very low and decreases at high speed, and when the excavation moment standard value Mn is very high and increases at high speed, the arm pulling operation is controlled in the stopping direction.

Regarding the bucket rotating operation, as shown in Table 7, as a general rule, when the excavation moment standard value is equal to or less than the reference value, control is performed so as to maintain neutrality.
Even in this case, since the excavation moment standard value Mn is likely to increase in the future when the moment time change amount ΔM is very large, the bucket retract operation is performed. On the contrary, even when the excavation moment standard value Mn is high, the excavation moment standard value Mn is likely to approach the standard value in the future when the time change amount ΔM is negative, that is, when the moment decreases. Therefore, the bucket retract operation is suppressed.

The same goes for the bucket lifting operation.
As shown in Table 8, when the excavation moment standard value Mn is close to the reference value and the amount of change ΔM is small, the control proceeds to the direction in which the bucket ascending / descending operation is not performed. Even if the excavation moment standard value Mn is decreasing, or if the excavation moment standard value Mn is lower than the reference value and there is an increasing tendency, the excavation moment standard value Mn is likely to return to the standard value in the future. Bucket raising operation is suppressed. On the other hand, when both the excavation moment standard value Mn and the time change amount ΔM are large, the bucket raising operation is promoted, and conversely, when the excavation moment standard value Mn and the time change amount ΔM are both small, the bucket lowering operation is performed. Is promoted. However, when both the excavation moment standard value Mn and the amount of change ΔM thereof with time are extremely low, abnormal excavation is currently occurring, or there is a high possibility that abnormal excavation will occur in the future. Control is performed in the raising direction.

According to such a device, not only the current value of the excavation moment but also the time variation thereof are taken into consideration, so that more efficient automatic excavation can be performed while predicting future fluctuations in the excavation moment. Can be realized. In addition, such control that also considers the moment time change amount can be applied to a wheel loader and other work machines, and can also be applied to a case of performing rocking excavation instead of normal excavation. Further, instead of the fuzzy control as described above, a limit value is set for both the excavation moment and its time change amount as in the first embodiment, and the drive control of the bucket 1 is performed by comparison with this limit value. You may do it.

The present invention is not limited to the above embodiments, and the following modes can be adopted as examples.

(1) In the first embodiment, the cylinder pressure sensor 14 for detecting the cylinder pressure of the bucket cylinder 5 is used as the means for detecting the acting force for rotating the bucket 1. However, the present invention is not limited to this. Not limited to this, various types can be substituted as long as the acting force can be detected.
For example, the same effect as described above can be obtained by using a strain sensor that detects the strain of the shaft 10 that transmits the rotational force to the bucket and the strain of the link 4 connected to the shaft 10.

(2) In the first embodiment, as the means for detecting the bucket attitude, the rotation angle of the bucket 1 with respect to the boom 2 and the rotation angle of the boom 2 with respect to the main body 8 are detected. The bucket attitude can be detected by detecting other values. For example, in the case of a wheel loader, detection of the ground angle of the bucket 1 and the rotation angle of the bucket 1 with respect to the boom 2, detection of the length of the bucket cylinder 5 and the length of the boom cylinder 2,
Alternatively, it is possible to grasp the bucket attitude by detection by appropriately combining these values. In the case of a hydraulic excavator, the ground angle of the bucket 1 and the arm angle of the bucket 1 are detected, or the ground angle of the bucket 1 and the bucket angle are detected. Cylinder 5
It is possible to grasp the bucket attitude by detecting the length of the bucket 1, the angle of the arm 1 of the bucket 1, the angle of the boom of the arm 3 and the angle of the boom 2 of the main body, or a combination of the values described above. ..

(3) In the first and second embodiments, the limit value WM-
2, WM-3, HM-2, HM-3 and the like are always constant during excavation, but these values may be changed according to the bucket rotation angle in the middle of excavation. For example, when the limit values WM-2 and WM-3 are changed as shown in the graph of FIG. 16, the limit value WM-2 is low immediately after the start of the middle excavation period and immediately before the end of the middle excavation period. Will be encouraged. Further, since the excavation state is relatively unstable in the first half of the excavation period, a negative excavation moment may be temporarily generated even if the excavation is not abnormal. Since the negative value is set, it is possible to prevent the bucket 1 from being retracted more than necessary even though the excavation abnormality is not present.

Further, the limit value regarding the excavation moment or the limit value regarding the time variation amount of the excavation moment may be appropriately set according to the type and size of the machine.

(4) In the third and fourth embodiments, seven labels are set for the membership function of each variable, but the number of labels is appropriately set according to the structure of the machine and the contents of the variables. You can increase or decrease.

[0067]

According to the first aspect of the present invention, the work moment about the rotation axis of the bucket is momentarily calculated by detecting the bucket attitude and the acting force for rotating the bucket, and the bucket rotation is performed based on this work moment. Since the drive and the bucket ascending / descending drive are controlled, the following effects can be obtained.

(A) Since the bucket drive control is performed while the work moment is monitored during the work, the bucket can be operated while avoiding the point where the work resistance becomes extremely high. Therefore, unlike the conventional device that controls the work trajectory regardless of the work moment, the bucket is not subjected to a large load at the above points to reduce the durability and the traveling speed of the bucket does not decrease extremely. Even an unskilled operator can perform a smooth and highly efficient work (a large loading amount and a short cycle time) without giving a heavy load. Further, there is also an advantage that energy consumption during excavation is reduced.

(B) Since the control is based on the work moment regardless of the trajectory of the bucket, it is possible to flexibly respond to a wide range of work conditions regardless of the work target or the ground shape. Therefore, it is particularly effective when the work object is non-uniform or the ground shape is complicated.

(C) At a minimum, control is possible as long as the value required to calculate the work moment is detected, so the required number of sensors is greatly reduced compared to the case of performing excavation trajectory control. Since the calculation contents are simplified, the required capacity of the CPU is also small, and thus the cost can be significantly reduced.

Further, according to the second aspect of the present invention, in addition to the work moment, the time change amount thereof is calculated, and the bucket rotation drive and the bucket elevation drive are controlled based on both values. By considering not only the current work moment value but also its increase / decrease tendency, control can be performed while predicting future fluctuations in the excavation moment, and more efficient automatic excavation can be realized. effective.

[Brief description of drawings]

FIG. 1 is a block diagram of an excavation control device according to a first embodiment of the present invention.

FIG. 2 is an overall side view of a wheel loader provided with the excavation control device.

FIG. 3 is a graph showing a control operation example by the excavation control device.

FIG. 4 is a graph showing a change over time in an excavation state during excavation by a driver's manual operation.

FIG. 5 is a graph showing a change over time in an excavation state during excavation under the control of the excavation control device.

FIG. 6 is an overall side view of a backhoe provided with an excavation control device in a second embodiment.

FIG. 7 is a graph showing a control operation example by the excavation control device.

FIG. 8 is an overall side view of a loading shovel provided with an excavation control device.

FIG. 9 is a diagram showing a membership function of an excavation moment standard value which is a variable used in fuzzy control in the third embodiment.

FIG. 10 is a diagram showing a membership function of a bucket rotation operation signal output value which is a variable used in the fuzzy control.

FIG. 11 is a diagram showing a membership function of a bucket raising operation signal output value which is a variable used in the fuzzy control.

FIG. 12 is a block diagram of an excavation control device according to a fourth embodiment.

FIG. 13 is a diagram showing a membership function of a moment time change amount which is a variable used in fuzzy control performed by the excavation control device.

FIG. 14 is a diagram showing a membership function of an arm pulling motion command signal output amount, which is a variable used in the fuzzy control.

FIG. 15 is a graph showing a control operation example by the excavation control device.

FIG. 16 is a graph showing an example of setting a limit value of excavation moment.

[Explanation of symbols]

1 Bucket 2 Boom 3 Arm 5 Bucket Cylinder (Bucket Rotation Drive Means) 6 Boom Cylinder (Bucket Lifting Drive Means) 8 Main Body 14 Cylinder Pressure Sensor (Working Force Detection Means) 16 Boom Angle Sensor (Constitutes Bucket Attitude Detection Means) 18 Bucket Angle sensor (constitutes bucket attitude detecting means) 20 Controller 21 Bucket attitude calculating means (constitutes bucket attitude detecting means) 22 Moment calculating means 23 Bucket rotation control calculating section 24 Bucket lifting control calculating section 25 Moment time change amount calculating means

Claims (2)

[Claims] 1. A bucket, a bucket support member that rotatably supports the bucket, a main body that rotatably supports the bucket support member, and a bucket rotation drive means that rotates the bucket with respect to the bucket support member. In a working machine including a bucket elevating and lowering drive unit that elevates and lowers the bucket with respect to a work surface by rotating the bucket support member with respect to the main body, a bucket attitude detection unit that detects the attitude of the bucket, and a bucket Action force detection means for detecting the action force to rotate, moment calculation means for momentarily calculating the work moment around the rotation axis of the bucket from the bucket attitude and action force, and bucket rotation drive based on the calculated work moment Bucket rotation control means for controlling the A work control device, comprising: a bucket up-and-down control means for controlling the up-and-down drive of the bucket. 2. A bucket, a bucket support member that rotatably supports the bucket, a main body that rotatably supports the bucket support member, and a bucket rotation drive unit that rotates the bucket with respect to the bucket support member. In a working machine including a bucket elevating and lowering drive unit that elevates and lowers the bucket with respect to a work surface by rotating the bucket support member with respect to the main body, a bucket attitude detection unit that detects the attitude of the bucket, and a bucket An acting force detecting means for detecting an acting force to rotate, a moment calculating means for momentarily calculating the working moment of the bucket from the bucket attitude and the acting force, and a moment for calculating the time change amount of the moment to be calculated. Based on the time change amount calculation means, the work moment and the time change amount thereof A work control apparatus comprising: a bucket rotation control means for controlling bucket rotation drive and a bucket lifting control means for controlling bucket lifting drive based on the work moment and the time variation thereof.