JPH11241363A - Front control device for construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front control device for a construction machine in which the whole body of a front member is not stopped even when the front member reaches a limit position. SOLUTION: A front drive hydraulic cylinder to drive an articulated front member comprising a first boom, etc., front drive direction control valves including a first boom direction control valve, an angle sensor 11 or the like to detect a height position of a monitor point(MP1) or the like provided on the front member, a limit position setting means 50 to set a limit height T, a lowering amount setting means 51 to set a lowering amount L, and a limit position control command means 52 are provided. A control unit 70 to control drive of the front control direction control valves determines if the height position of at least one monitor point (MP1) reaches the limit height T or not, and an automatic operation means 63 is provided to automatically retreat the corresponding monitor point(MP1) for the lowering amount L when it is determined that it reaches the limit height T.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction machine such as a hydraulic shovel, and more particularly to a movement of a rotatable front member when the front member attempts to enter a predetermined prohibited area. The present invention relates to a front control device for a construction machine capable of controlling a vehicle.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No.
There is one described in JP-A-06534.

A conventional backhoe, that is, a hydraulic shovel, includes a multi-joint front member composed of a rotatable first boom, a second boom, an arm, a bucket, and the like, and these front members. A front drive hydraulic cylinder to be driven, a front control directional control valve for controlling the flow of pressure oil supplied to these front drive hydraulic cylinders, and an operating device for operating these front control directional control valves, Attitude detection means, which is provided at each joint of the front member and includes an angle sensor for detecting the attitude formed by the front member, and a limit position which is a boundary of a prohibited area where the intrusion of the front member is prohibited,
For example, a limit position setting means for setting a limit position in the height direction, and when the attitude of the front member calculated based on the detection signal output from the angle sensor described above reaches the limit position described above, And a control device for performing a control operation for preventing the front member from entering the prohibition region formed in the above, that is, a control operation for immediately returning the front control directional control valve to the neutral position.

In this prior art, when the front member reaches the limit position, the directional control valve for front control is returned to the neutral position by the signal output from the control device as described above, and the hydraulic oil is supplied to the front drive hydraulic cylinder. Supply is stopped,
The front member is immediately held at a standstill, thereby preventing the front member from entering the prohibited area formed upward.

[0005]

In the above-mentioned prior art, the front member can be prevented from entering the forbidden area set in advance, so that the front member collides with an obstacle arranged in the forbidden area. Accordingly, it is possible to prevent the corresponding obstacle or the front member from being damaged.

However, when the front member reaches the limit position, the directional control valve for front control is returned to the neutral position as described above, whereby the entire front member is stopped. Is activated, the operator must once manually lower the front member by manually operating an operating device for rotating the front member in order to release such limit position control. Then, subsequently, the operating device is operated to rotate the front member for a desired excavation work or the like.

[0007] As described above, in the prior art described above,
When the front member stops at the limit position during a desired excavation operation or the like, a manual operation by an operator for separating the front member from the limit position is indispensable for releasing the limit position control. There is a problem that it becomes complicated and the operability tends to decrease.
There is also a problem that the work efficiency is likely to be reduced because the restart from the stop of the front member is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned situation in the prior art, and has as its object to stop the entire front member even when the front member reaches a limit position which is a boundary of a prohibited area. It is an object of the present invention to provide a front control device for a construction machine capable of performing a non-control operation.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, a hydraulic cylinder for driving a front drive for driving a multi-joint front member and a hydraulic cylinder for the front drive are provided. Direction control valve for controlling the flow of pressurized oil to be applied, attitude detecting means for detecting the attitude of the front member, and a limit for setting a limit position which is a boundary of a prohibition area where the intrusion of the front member is prohibited. Position setting means, and control means for controlling driving of the front control direction control valve so as to prevent the front member from entering the prohibited area from the limit position based on a detection signal output from the attitude detection means. In the front control device for a construction machine provided with the above, the posture detecting means may detect positions of a plurality of monitor points set in advance on the front member. Together with those which detect, said control means, at least one position of the monitor points detected by the posture detection means,
It is determined whether or not the limit position set by the limit position setting means has been reached, and when it is determined that the limit position has been reached, an automatic operation means for operating the front member in a direction away from the limit position is provided. is there.

According to the first aspect of the present invention, at least one position of the monitor point detected by the posture detecting means reaches a limit position which is a boundary of the prohibited area set by the limit position setting means. When the determination is made by the control means, the automatic operation means included in the control means is operated to perform an operation of moving the front member in a direction away from the limit position. Therefore, even in such a case, the entire front member is not stopped.

According to a second aspect of the present invention, in the first aspect of the present invention, the front member has a work implement at a tip end thereof, and the automatic operation means of the control means is provided with the automatic operation means. When it is determined that at least one of the monitor points detected by the posture detecting means has reached the limit position set by the limit position setting means, a predetermined portion on the work implement is substantially the same. While maintaining the position, the front member is operated in a direction away from the limit position.

According to the second aspect of the present invention, when the front member is automatically separated from the limit position by a predetermined distance, the automatic operation means keeps a predetermined portion on the work implement at substantially the same position. Since the front member is operated while the front member is retracted from the limit position, the position of the work implement can be maintained at the position when the front member reached the limit position, even though the operation of retracting the front member from the limit position is performed. Can be maintained in a state that is convenient for work such as excavation work that is continuously performed.

According to a third aspect of the present invention, in the first or second aspect of the present invention, when the automatic operating means determines that the vehicle has reached the limit position, the automatic operation means moves the front member to the limit position. It is configured to be separated from the position by a predetermined distance.

According to a fourth aspect of the present invention, in the first aspect of the present invention, there is provided a limit position control commanding means for commanding the operation of the automatic operating means of the control means. And a separation distance setting means for setting the predetermined distance, wherein the automatic operation means sets at least one of the monitor points detected by the attitude detection means by the limit position setting means. It is determined whether or not the limit position has been reached, and whether or not the command signal of the limit position control command means has been input, and a limit for separating the front member from the limit position by a predetermined distance in accordance with both of these determination results. The automatic control execution availability determination means for determining whether to execute the position control and the automatic control execution availability determination means determine that the limit position has been reached. Further, when it is determined that the command signal of the limit position control command means has been input and the decision to execute the limit position control is made, the front distance corresponding to the predetermined distance set by the separation distance setting means is determined. Front drive calculating means for calculating the drive amount of the member,
Output means for outputting a drive signal corresponding to the drive amount calculated by the front drive amount calculating means as a signal for operating the front control directional control valve.

According to the fourth aspect of the present invention, the operation of the automatic operation means of the control means is commanded by the limit position control command means, and the distance for separating the front member from the limit position is set by the separation distance setting means. In this state, when the front member reaches the limit position which is the boundary of the intrusion prohibition area, it is determined that the automatic control execution possibility determining means executes the limit position control for separating the front member from the limit position by a predetermined distance. In response, the front drive amount calculation means calculates a front drive amount for moving the corresponding monitor point backward by the above-described predetermined distance. A drive signal corresponding to the drive amount is output from the output means, and the directional control valve for front control operates according to the drive signal. Therefore, the pressure oil is continuously supplied to the front drive hydraulic cylinder via the front control direction control valve, and the above-described monitor point is moved by a predetermined distance set by the separation distance setting means by the expansion and contraction operation of the front drive hydraulic cylinder. , Can be retracted from the limit position, and the entire front member does not stop.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the construction machine comprises a hydraulic shovel.

In the fifth aspect of the present invention, the excavator generally sets an intrusion-inhibited area of the front member during excavation work or the like performed through rotation of the front member. Therefore, the invention according to claims 1 to 4 can be effectively utilized.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a front control device for a construction machine according to the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a hydraulic shovel to which an embodiment of a front control device for a construction machine according to the present invention is applied, FIG. 2 is a circuit diagram showing an overall configuration of the embodiment of the present invention, and FIG. FIG. 4 is a block diagram showing a control unit provided in the embodiment;
4 is a flowchart showing a processing procedure in the control unit shown in FIG.

First, a schematic configuration of a hydraulic shovel to which the present embodiment is applied will be described with reference to FIG. The hydraulic excavator shown in FIG. 1 includes a traveling body 1 that is mounted on a ground contact surface 15 and travels, a revolving body 2 that is provided on the traveling body 1 so as to be capable of turning, and has a driver's cab, A first boom 3 rotatably connected to the up and down direction, a second boom 4 rotatably connected to the end of the first boom 3 in the up and down direction,
A bucket 6 is connected to the tip of the second boom 4 so as to be rotatable in the vertical direction, and constitutes a work implement. The above-described first boom 3, second boom 4, arm 5, and bucket 6 constitute a multi-joint front member.

A first boom cylinder 7 for rotating the first boom 3, a second boom cylinder 8 for rotating the second boom 4, an arm cylinder 9 for rotating the arm 5, and a bucket for rotating the bucket 6. A cylinder 10 is provided. These cylinders 7 to 10 constitute a front drive hydraulic cylinder.

A first boom angle sensor 11 for detecting a relative rotation angle of the first boom 3 with respect to the revolving unit 2 and a second boom angle for detecting a relative rotation angle of the second boom 4 with respect to the first boom 3 A sensor 12, an arm angle sensor 13 for detecting a relative rotation angle of the arm 5 with respect to the second boom 4, and a bucket angle sensor 14 for detecting a relative rotation angle of the bucket 6 with respect to the arm 5 are provided. Each of these angle sensors 11 to 14 constitutes a part of a posture detecting means for detecting the posture of the front member as described later.

A plurality of monitor points are set on the front member in advance. For example, the monitor point MP1 is set at the cutting edge of the bucket 6, the monitor point MP2 is set at the root of the bucket 6, the monitor point MP3 is set at the end of the arm 5, and the monitor point MP4 is set at the end of the second boom 4. I have. These monitor points MP1 to MP4 are points that reach a height position that can be regarded as a substantially highest position depending on the attitude of the front member. In addition, the above-described posture detecting means detects, for example, the height positions of the plurality of monitor points MP1 to Mp4.

In FIG. 1, reference numeral 16 denotes an obstacle, such as a building, which hinders the collision of the front member, and reference numeral 17 denotes an imaginary limit height line which forms a boundary of a prohibited area in which the front member is prohibited from entering. , T is a limit height which is a dimension between the ground contact surface 15 and the limit height line 17, and L is automatically retracted from the limit height line 17 when the front member reaches the limit height T as described later. A predetermined lowering amount 18 at the time of making is a virtual set lowering height line formed at a position of the lowering amount L from the limit height line 17.

Next, a front control device of the present embodiment provided in the hydraulic shovel configured as described above will be described with reference to FIGS.

In FIG. 2, reference numerals 7 to 10 denote a first boom cylinder, a second boom cylinder, an arm cylinder,
Bucket cylinders and 11 to 14 are a first boom angle sensor, a second boom angle sensor, an arm angle sensor, and a bucket angle sensor, respectively, which are described above.

In the present embodiment, a main hydraulic pump 20 for supplying pressure oil to a cylinder 7 to 10 and a turning motor 22 for turning the revolving unit 2, and a pressure of the pressure oil discharged from the main hydraulic pump 20 are set. In addition to the main relief valve 21, a pilot pump 28 for supplying pilot pressure oil and a pilot relief valve 29 for setting the pressure of the pressure oil discharged from the pilot pump 28 are provided.

The main hydraulic pump 20 is connected to the cylinders 7 to
10, a first boom directional control valve 23, a second boom directional control valve 24, an arm directional control valve 25, a bucket directional control valve 26 for controlling the flow of pressure oil supplied to the turning motor 22, respectively, The directional control valve 27 is provided.
Of the directional control valves 23 to 27 described above, the directional control valve 2
Reference numerals 3 to 26 constitute a front control directional control valve for controlling the drive of the front member.

The above-mentioned direction control valves 23 to 26 are operated, for example, by operating an operation device having an electric lever, that is, a first boom operation device 38, a second boom operation device 39, an arm operation device 40, a bucket, respectively. Operating device 4
1, and the turning direction control valve 27 is operated, for example, by operating a turning operation device 42 formed in a pilot operation type.

The pilot pump 28 and each directional control valve 2
Electromagnetic proportional pressure reducing valves 30 to 37 are provided in a pilot line communicating with each of the control rooms 3 to 26. Among them, the electromagnetic proportional pressure reducing valves 30 and 31 reduce the pilot pressure for operating the first boom directional control valve 23 in one predetermined direction or in the opposite direction, and the electromagnetic proportional pressure reducing valve 3
2, 33 reduce the pilot pressure for operating the second boom directional control valve 24 in one predetermined direction or in the opposite direction, and the electromagnetic proportional pressure reducing valves 34, 35 control the arm directional control valve 25. The pilot pressure to be operated in one predetermined direction or in the opposite direction is reduced, and the electromagnetic proportional pressure reducing valves 36 and 37 operate the bucket direction control valve 26 in one predetermined direction or in the opposite direction. This is to reduce the pilot pressure.

Each of these electromagnetic proportional pressure reducing valves 30 to 37 outputs a drive signal a1, a2, b1, b2, c1, c
2, d1 and d2.

As shown in FIG. 3, in the present embodiment, a limit position setting means 50 for setting a limit position which is a boundary of a prohibition region where the intrusion of the front member is prohibited, for example, the above-described limit height T in FIG. Separation distance setting means for setting a predetermined distance for retreating the front member from the limit height T, that is, the descent amount setting means 5 for setting the descent amount L in FIG.
1 and limit position control for commanding execution of limit position control for moving the front member away from the limit position by a predetermined distance, that is, limit position control for automatically retracting the front member by the amount of descent L when the front member reaches the limit height T. Command means 52.

Each of the limit position setting means 50, the descent amount setting means 51, and the limit position control command means 52 is provided, for example, in the vicinity of the driver's seat in the cab of the revolving unit 2. The limit position control commanding means 52 is mounted on the head of the grip portion of the electric lever of the arm operating device 40 as shown in FIG.

In the present embodiment, the front member intrudes upward from the limit height T based on the signals output from the angle sensors 11 to 14 constituting a part of the attitude detecting means. The control unit 70 controls the driving of the direction control valves 23 to 26 so as to prevent the operation from being performed.

The control unit 70 includes input / output, arithmetic,
It has a storage and logic judgment function, and is constituted by, for example, a microcomputer and incorporates each means shown in FIG.

That is, the control unit 70 controls the first boom operating device 38 based on a signal corresponding to the operation amount of the first boom operating device 38.
A first boom cylinder operation amount calculating means 53 for calculating a target operation amount of the boom cylinder 7, and a second boom operating device 3
A second boom cylinder operation amount calculating means 54 for calculating a target operation amount of the second boom cylinder 8 based on a signal corresponding to the operation amount of the arm 9; and an arm based on a signal corresponding to the operation amount of the arm operating device 40. Arm cylinder operation amount calculation means 55 for calculating the target operation amount of the cylinder 9, and bucket cylinder operation amount calculation means 56 for calculating the target operation amount of the bucket cylinder 10 based on a signal corresponding to the operation amount of the bucket operating device 41. And Further, the control unit 70 controls the monitor point M shown in FIG. 1 based on the signals output from the angle sensors 11 to 14 described above.
A monitor point height calculating means 57 is provided for calculating the height positions of P1 to MP4 and obtaining the maximum height of the height positions and the monitor point at the maximum height. This monitor point height calculating means 57;
The above-mentioned angle sensors 11 to 14 constitute a posture detecting means for detecting the posture of the front member.

The control unit 70 includes a limit position storage means 58 for storing the limit height T output from the limit position setting means 50, and a descent amount setting means 51 described above.
Amount storage means 59 for storing the amount of decrease L output from
And

The control unit 70 determines whether at least one of the monitor points MP1 to MP4 detected by the attitude detecting means has reached the limit height T, and has determined that the position has reached the limit height T. At this time, it includes an automatic operation means 63 for lowering the front member from the limit height T by a lowering amount L and operating in a direction away from the limit position.

The automatic operation means 63 determines whether or not the maximum height of the monitor point obtained by the monitor point height calculation means 57 has reached the limit height T stored in the limit position storage means 58. It is determined whether or not the command signal of the position control command means has been input, and the monitor point corresponding to the above-mentioned maximum height included in the front member, for example, the front member, is lowered by the lowering amount L according to both of these determination results. The automatic control execution availability determination means 60 for determining whether to execute the limit position control to be performed, and the automatic control execution availability determination means 60, determine that the maximum height of the monitor point has reached the limit height T, and When it is determined that the command signal of the limit position control command means 52 has been input and the decision to execute the limit position control is made, for example, For example, while keeping a desired portion on the gantry 6 at substantially the same position, for example, keeping the entire bucket 6 in a state where it is not displaced, the monitor point of the maximum height is lowered by the amount L, ie, the set descent height of FIG. Line 18
Front drive amount calculation means 6 for calculating the respective operation amounts of the first boom cylinder 7, the second boom cylinder 8, the arm cylinder 9, and the bucket cylinder 10 for lowering
1 and a drive signal corresponding to the drive amount calculated by the front drive amount calculation means 61 and a drive signal corresponding to the operation amount calculated by each of the operation amount calculation means 53 to 56 described above. And output means 62 for outputting drive signals a1 or a2, b1 or b2, c1 or c2, d1 or d2 for operating signals 23 to 26.

Hereinafter, the operation in the present embodiment configured as described above will be described with reference to FIG. Now, it is assumed that excavation work such as digging for piping is performed in a situation where the hydraulic excavator is disposed immediately below the obstacle 16 as shown in FIG. 1, for example. In such a case, the limit position setting means 50 is operated to set the limit height T from the ground contact surface 15 of the excavator, and the descent amount setting means 51 is operated to set the retreat amount from the limit height T, ie, The lowering amount L is set, and the limit position control command means 52 is operated to execute the limit position control.

At the time of excavation work, the first boom operating device 38, the second boom operating device 39, and the arm operating device 4
0 and the corresponding one of the bucket operating devices 41 is operated, the operation signal is input to the control unit 70, and the first boom cylinder operation amount calculating means 53 of the control unit 70, the second boom cylinder Each of the operation amount calculation means 54, the arm cylinder operation amount calculation means 55, and the bucket cylinder operation amount calculation means 56 calculates a target operation amount corresponding to the value of the operation signal, and outputs a drive signal a1 or a drive signal a1 corresponding to the target operation amount. a2, b1 or b2, c1
Alternatively, c2, d1 or d2 is output from the output unit 62 in FIG.
Is output to the corresponding one of the electromagnetic proportional pressure reducing valves 30 to 37 shown in FIG.

Accordingly, the corresponding electromagnetic proportional pressure reducing valves 30 to
37 is driven so as to have an opening amount corresponding to the target operation amount, and the pressure oil of the pilot pump 28 is supplied to the corresponding one of the directional control valves 23 to 26 through the corresponding electromagnetic proportional pressure reducing valves 30 to 37. And the first boom cylinder 7, the second boom cylinder 8,
Supplied to each of the arm cylinder 9 and the bucket cylinder 10, these cylinders 7 to 10 expand and contract as appropriate, and the first boom 3, the second boom 4, the arm 5 and the bucket 6 rotate, and a desired excavation operation is performed. Is done.

During such excavation work, the control unit 7
0 is a signal output from the limit position control command means 52, a signal output from the limit position setting means 50 (limit height T), and a signal output from the descent amount setting means 51, as shown in FIG. The lowering amount L) and the signals output from the angle sensors 11 to 14 are input (step S1).

Next, based on the input signal from the limit position setting means 50, the limit position storage means 58 stores the limit height T (step S2), and based on the input signal from the descending amount setting means 51, The descending amount storage means 59 stores the descending amount L (step S3).

The monitor point height calculating means 57
Are a first boom angle sensor 11, a second boom angle sensor 12, an arm angle sensor 13, a bucket angle sensor 14
The height positions of the monitor points MP1 to MP4 shown in FIG. The calculation at this time is the same as the calculation generally performed in the trajectory control of the front member and the like, and thus the description thereof is omitted. Then, the maximum height and the monitor point located at the maximum height are obtained from the calculation result by the monitor point height calculation means 57 (step S4). Now, it is assumed that the monitor point MP3 is determined to be the monitor point having the maximum height as shown in FIG.

Next, the automatic control execution availability determination means 60 of the automatic operation means 63 determines whether or not a command signal from the limit position control command means 52 has been input (step S).
5). At this time, since the limit position control commanding means 52 is operated, this determination is YES. Here, the limit height T is read from the limit position storage means 58, and the automatic control execution availability determination means 60 determines whether the height of the monitor point MP3 obtained in step S4 is equal to or greater than the limit height T. (Step S7). Now, for example, assuming that the posture of the front member is the posture indicated by the two-dot chain line in FIG. 1 and has reached a state where the front member is determined to be equal to or higher than the limit height T, it is determined that the limit position control is to be performed. The lowering amount L stored in the lowering amount storage means 59 is read out to the front driving amount calculating means 61, and the monitor point MP3 is lowered by the front driving amount calculating means 61 to the set lowering height line 18 shown in FIG. Required for the first boom cylinder 7, the second boom cylinder 8, the arm cylinder 9,
And the driving amount of each of the bucket cylinders 10 is calculated. At this time, for example, the drive amount for lowering the monitor point MP3 to the set lowering height line 18 while maintaining the height position and the form of the bucket 6 in a stationary state is calculated (step S8).

Next, the first boom cylinder 7 is replaced with a drive signal corresponding to the operation amount calculated by the operation amount calculation means 53 to 56 which has been output from the output means 62 up to that time.
Each of the second boom cylinder 8, the arm cylinder 9, and the bucket cylinder 10 is provided with a drive signal a1 or a2, b1 or b2, c1, or c2, d of a value corresponding to the drive amount calculated by the front drive amount calculating means 61.
1 or d2 is output.

As a result, the corresponding electromagnetic proportional pressure reducing valves 30 to 37 shown in FIG. 2 are driven, and the pressure oil of the pilot pump 28 is applied to the corresponding electromagnetic proportional pressure reducing valves 30 to 37 as described above.
To the corresponding one of the directional control valves 23 to 26 via the directional control valves 23 to 26, and the first boom cylinder 7, the second boom cylinder 8, the arm cylinder 9, and the bucket cylinder 10 through the respective directional control valves 23 to 26. These cylinders 7 to 10 are appropriately expanded and contracted, and only the first boom 3, the second boom 4, and the arm 5 of the front member rotate to the posture shown by the broken line in FIG. Is held without displacement. In this way, the front automatic control in which the monitor point MP3 automatically retreats from the limit height T to the position of the descending amount L, that is, the set descending height line 18, that is, the limit position control is executed (procedure S).
9).

After the monitor point MP3 has descended to the set descending height line 18, the drive signal a1 or a2, b1 or b2 corresponding to the operation amount obtained from the output means 62 by the operation amount calculation means 53 to 56 again. c1 or c2, d1 or d2 is output, and each operating device 3
The front member can be driven by manual operation of 8-41.

In the above-described procedure S7, the automatic control execution availability determination means 60 determines that the height of the monitor point MP3, which is the maximum height monitor point, is lower than the limit height T, and When it is determined not to perform the control, the above-described front automatic control, that is, the limit position control is not executed (procedure S6). Therefore, the front member rotates according to the manual operation of each of the operation devices 38 to 41.

Also, the limit position control command means 52 is not operated, and the control unit 70
If no command signal is input from step 2, the determination in step S5 is NO, and the limit position control is not executed again (step S6).

As described above, according to the present embodiment, when the front member reaches the limit position which is the boundary of the prohibited area, the monitor point MP3 at the maximum height is set to the descending amount setting means 51.
The limit height line 17 is automatically adjusted by the amount of descent L set in
Can be retracted, that is, control without stopping the entire front member can be performed, and the limit position control can be released without bothering the operator, and excellent operability can be achieved. Is obtained.

Further, since the front member does not stop even when the front member reaches the limit position as described above, the starting operation of the front member from the stop is not necessary, thereby preventing a reduction in work efficiency.

When the front member is retracted from the limit position, the automatic operation means 63 rotates the front member so that the height position and the form of the bucket 6 are hardly changed. Drilling work, etc.
Contributes to improved work efficiency.

In the above embodiment, the automatic operation means 6
3, when the front member is retracted from the limit position,
Control is performed to keep the entire bucket 6 at substantially the same position. Instead of such control, a specific portion of the bucket 6, for example, the bucket angle sensor 14 shown in FIG.
May be carried out to keep only the portion where the bucket 6 is mounted at substantially the same position. In the case where the height position and form of the bucket 6 may be changed, the front member may be used. When retreating from the limit position,
The above-described control for keeping the bucket 6 at substantially the same position may not be performed.

In the above-described embodiment, the limit position control relating to the height of the front member is performed by obtaining the height positions of the monitor points MP1 to MP4. The present invention is not limited to performing the limit position control. The limit position control relating to the depth below the ground contact surface 15 may be performed. Limit control for obstacles located on the left and right sides of the vehicle.

In the above embodiment, four monitor points are provided on the front member. However, more monitor points are provided in consideration of the surrounding environment and the like when the limit position control is performed. Desired limit position control may be performed via the monitor point.

In the above embodiment, whether the height of the monitor points MP1 to MP4 has reached the limit height T is determined by the automatic control execution possibility determination means 60, and whether the limit position control is to be performed or not is determined. I'm trying to decide,
The present invention is not limited to this, the automatic control execution availability determination means 60 by determining whether the height of a specific portion of the front member around the monitor points MP1 to MP4 has reached the limit height T, It may determine whether to execute the limit position control.

[0058]

As described above, according to the present invention, when the front member reaches the limit position which is the boundary of the intrusion prohibition area, the front member moves from the limit position. Automatically retreats, control can be performed without stopping the whole front member, and the limit position control can be released without any trouble of the operator. Property is obtained. In addition, since the front member does not stop even when the front member reaches the limit position in this way, a start operation from the stop of the front member is unnecessary, thereby preventing a decrease in work efficiency.

According to the second aspect of the present invention,
While the front member is retracted from the limit position, the position of the work tool can be maintained at the position when the front member has reached the limit position, and the work tool can be maintained in a state convenient for the work to be performed continuously. This also contributes to the improvement of work efficiency.

[Brief description of the drawings]

FIG. 1 is a side view of a hydraulic shovel to which an embodiment of a front control device for a construction machine according to the present invention is applied.

FIG. 2 is a circuit diagram showing an entire configuration of an embodiment of the present invention.

FIG. 3 is a block diagram showing a control unit provided in the embodiment shown in FIG. 2;

FIG. 4 is a flowchart showing a processing procedure in the control unit shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Traveling body 2 Revolving structure 3 1st boom (front member) 4 2nd boom (front member) 5 Arm (front member) 6 Bucket (front member) 7 1st boom cylinder (front drive hydraulic cylinder) 8 2nd boom Cylinder (hydraulic cylinder for front drive) 9 Arm cylinder (hydraulic cylinder for front drive) 10 Bucket cylinder (hydraulic cylinder for front drive) 11 First boom angle sensor (posture detecting means) 12 Second boom angle sensor (posture detecting means) DESCRIPTION OF SYMBOLS 13 Arm angle sensor (posture detecting means) 14 Bucket angle sensor (posture detecting means) 15 Contact surface 16 Obstacle 17 Limit height line 18 Setting descending height line 20 Main hydraulic pump 21 Main relief valve 22 Swing motor 23 First boom Direction control valve (directional control valve for front control) 24 2 Boom directional control valve (front control directional control valve) 25 Arm directional control valve (front control directional control valve) 26 Bucket directional control valve (front control directional control valve) 27 Swing directional control valve 28 pilot Pump 29 Pilot relief valve 30 Proportional pressure reducing valve 31 Proportional pressure reducing valve 32 Proportional pressure reducing valve 33 Proportional pressure reducing valve 34 Proportional pressure reducing valve 35 Proportional pressure reducing valve 36 Proportional pressure reducing valve 37 Proportional pressure reducing valve 38 For first boom Operating device 39 Operating device for second boom 40 Operating device for arm 41 Operating device for bucket 42 Operating device for turning 50 Limit position setting means 51 Lowering amount setting means (separation distance setting means) 52 Limit position control commanding means 53 First boom Cylinder operation amount calculation means 54 Second boom cylinder operation amount calculation means 55 Arm Cylinder operation amount calculation means 56 bucket cylinder operation amount calculation means 57 monitor point height calculation means (posture detection means) 58 limit position storage means 59 descent amount storage means 60 automatic control execution availability determination means 61 front drive amount calculation means 62 output means 63 Automatic operating means 70 Control unit (control means) T Limit height L Lowering amount MP1 to MP4 Monitor point

Claims (5)

[Claims] 1. A front drive hydraulic cylinder for driving a multi-joint front member, a front control directional control valve for controlling a flow of pressure oil supplied to the front drive hydraulic cylinder, and a posture of the front member Position detection means for detecting the position of the front member, limit position setting means for setting a limit position that is a boundary of a prohibition region for prohibiting the intrusion of the front member, and detection of the front member based on a detection signal output from the posture detection means. Control means for controlling driving of the front control directional control valve so as to prevent entry into the prohibited area from the limit position. Detecting the positions of a plurality of monitor points set in advance, and the control means detects the posture detection It is determined whether at least one position of the monitor points detected in the step has reached the limit position set by the limit position setting means, and when it is determined that the limit position has been reached, the front member is moved. A front control device for a construction machine, comprising automatic operation means for operating in a direction away from the limit position. 2. The apparatus according to claim 1, wherein the front member has a work implement at a tip end thereof, and the automatic operation means of the control means determines that at least one of the monitor points detected by the attitude detection means is at the limit. When it is determined that the limit position set by the position setting means has been reached, the front member is moved in a direction away from the limit position while maintaining a predetermined portion on the work implement at substantially the same position. The front control device for a construction machine according to claim 1, wherein 3. The front control of a construction machine according to claim 1, wherein said automatic operation means moves said front member away from said limit position by a predetermined distance when determining that said limit position has been reached. apparatus. 4. A limit position control commanding means for commanding the operation of the automatic operating means of the control means, and a separation distance setting means for setting the predetermined distance, wherein the automatic operating means is controlled by the attitude detecting means. It is determined whether at least one of the detected monitor points has reached the limit position set by the limit position setting means, and whether a command signal from the limit position control command means has been input. Automatic control execution availability determining means for determining whether to execute limit position control for separating the front member from the limit position by a predetermined distance in accordance with both of these determination results; and Is determined to have reached the limit position, and it is determined that the command signal of the limit position control command means has been input. When the decision to execute is made, the front drive calculating means for calculating the drive amount of the front member corresponding to the predetermined distance set by the separation distance setting means; 4. A front control device for a construction machine according to claim 1, further comprising an output unit that outputs a drive signal corresponding to a drive amount as a signal for operating the front control directional control valve. . 5. The front control device for a construction machine according to claim 1, wherein the construction machine is a hydraulic shovel.