JPH09105152A - Work range limit control device of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an actuator from moving accidentally by handling a lever so that a front device may not advance into an advancing prohibition area or no shocks may be generated when halting the front device directly in front of the preliminarily determined advancing prohibition area in a work range limit control device of a construction machine. SOLUTION: A command current value under speed reduction control is calculated at arithmetic operation units 9b to 9h of a control unit 9 so that the calculated values are output to proportional solenoid valves 10a to 11b. When a monitor point approaches an approach prohibition area, the front device reduces the speed, and when it arrives at the approach prohibition area, the front device is halted. When the monitor point enters a specified range in front of the approach prohibition area at the arithmetic operation unit 91, a command current value is changed to a low current value, thereby halting the front device completely by full closing of the solenoid valves. An arithmetic operation unit 91 is arranged to compute hysteresis arithmetic operation which changes the distance in a specified range with the direction which approaches the approach prohibition area and the direction which is separated therefrom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work range limiting control device for construction machines such as hydraulic excavators.

[0002]

2. Description of the Related Art In a hydraulic excavator, a boom is attached to a front portion of an upper swing body, and an arm and a bucket are sequentially connected to a tip portion of the boom to form a work front device. Then, excavation and loading work is performed by operating the bending work motion of the work front device.

When working with such a hydraulic excavator, there may be obstacles above or below depending on the work site. For example, an electric wire is used for outdoor work, and a ceiling is an upper obstacle for indoor work. Also, in excavation work when gas pipes, water pipes, etc. are underground, these are obstacles below. The operator needs to pay close attention not to allow the bucket toes or the like to come into contact with or be caught by these obstacles during work.

With respect to such a problem, Japanese Patent Laid-Open No. 3-20
Inventions such as those described in Japanese Patent No. 8923 and Japanese Patent Publication No. 6-19165 are made. JP-A-3-208
In the invention described in Japanese Patent No. 923, an intrusion prohibition region of the front device is set in advance above, a deceleration region of the actuator is set below the invasion prohibition region, and the maximum height of each tip position of the front device is set. When a certain part enters this deceleration area, the discharge amount of the hydraulic pump is reduced to reduce the operating speed of the actuator, and when it reaches the intrusion prohibited area, the main pressure of the pilot operating device is cut off and the operation of the actuator is stopped. This is to prevent a part of the working machine from coming into contact with an obstacle above.

Further, the invention described in Japanese Patent Publication No. 6-19165 discloses an operation pilot pressure between a pilot operating device and a flow control valve operated by the operation pilot pressure output from the pilot operating device. An electric pressure reducing valve that decompresses and outputs the electric pressure reducing valve is provided, and when the boom rises to a set height, an electric signal for decompressing the electric type pressure reducing valve is output to reduce the operating pilot pressure and stop the boom raising. It is a thing.

[0006]

[Problems to be Solved by the Invention] Japanese Patent Publication No. 6-19165
In the publication, as described above, the electric pilot pressure reducing valve is used to reduce the operating pilot pressure, and when the boom is raised to the set height, the raising of the boom is stopped. Further, if the electric pressure reducing valve described in Japanese Patent Publication No. 6-19165 is used in the invention of Japanese Patent Laid-Open No. 3-208923, the electric type pressure reducing valve is changed according to the distance between the boom and the set height (intrusion prohibited area). By adjusting the electrical signal applied to the pressure reducing valve,
When the boom approaches the set height, the degree of pressure reduction by the electric pressure reducing valve can be increased to reduce the operating speed of the actuator and reduce the operating speed of the boom. However, when the deceleration control is performed using the electric pressure reducing valve in this way, there are the following problems.

When an electric pressure reducing valve is arranged between the pilot operating device and the flow control valve, the operating pilot pressure output from the pilot operating device is inadvertently reduced, and the speed of the actuator does not meet the operator's will. We must make sure that there is no decline. For this reason, the electric pressure reducing valve is normally operated by an electric valve in order to always supply the hydraulic pressure of the pilot pump, which is the hydraulic pressure source of the pilot operating device (pilot pump source pressure), to the flow control valve unless necessary. The maximum current flows as the current value of the signal, and the valve is fully opened. Then, for example, when the boom approaches the set height or depth, the current value of the electric signal is gradually decreased, the pressure reducing valve is closed, the speed of the actuator is gradually decreased, and the actuator is smoothly stopped at the end.

However, in the process of deceleration control as described above, the operating speed of the boom is considerably slowed immediately before the intrusion prohibition region, so that the current value is reached before the actuator is completely stopped by the stop process in the deceleration control. Before dropping, the operator may return the operation lever to the neutral position to reduce the operation pilot pressure output from the pilot operation device to zero and stop the actuator. In such a stopped state, the current value of the electric signal for deceleration control has not dropped to the current value at which the actuator is completely stopped, so the electric pressure reducing valve is slightly opened, for example, a hydraulic pressure of about several Kg / cm ² is applied. It is ready to output. The hydraulic pressure that can be output by the electric pressure reducing valve in this state is Ps. In this state, when the operator again moves the boom in the direction closer to the intrusion prohibited area, the operating pilot pressure is raised by operating the operating lever, and the electric pressure reducing valve instantaneously changes the operating pilot pressure to Ps due to the hydraulic response delay. The pressure cannot be reduced, and surge pressure rises for a short time depending on the open state of the electric pressure reducing valve, the flow control valve momentarily moves according to the surge pressure, and the actuator slightly moves.
For this reason, although the boom should have stopped for the operator, the actuator may be inadvertently moved by the subsequent lever operation, and the front device may pop out and enter the intrusion prohibited area depending on the magnitude of surge pressure. Must pay attention. Further, when the boom moves due to the surge pressure, some shock is accompanied, which makes the operator uncomfortable.

It is an object of the present invention to, when the front device is stopped immediately before a preset entry prohibition area, the actuator is inadvertently moved by the subsequent lever operation to enter the entry prohibition area, It is an object of the present invention to provide a work range limiting control device for a construction machine that does not cause a shock.

[0010]

In order to achieve the above object, the present invention employs the following constitution. That is, a multi-joint type front device configured by a plurality of vertically rotatable front members, a plurality of hydraulic actuators that drive the plurality of front members, and a plurality of units that direct the operation of the plurality of front members. And a plurality of flow rate control valves that are driven according to the operation of the plurality of operation means and that control the flow rate of the pressure oil supplied to the plurality of hydraulic actuators. Provided to a construction machine that is a plurality of pilot operating devices that output pilot pressure and drive corresponding flow control valves, and issue a command according to the distance between a preset monitor point and a preset intrusion prohibited area for the front device. The current value is calculated and output, and when the monitor point approaches the intrusion prohibition area, the front device is decelerated and the intrusion prohibition is performed. In a work range limitation control device for a construction machine that stops the front device when reaching a zone, the pilot operation device is provided between at least one of the plurality of pilot operation devices and a plurality of flow control valves corresponding thereto. The command current value is calculated so as to decrease as the distance between the monitor point and the intrusion prohibition area decreases, and an electric pressure reducing valve that reduces the operation pilot pressure output from the control pilot pressure according to the command current value and outputs the operation pilot pressure. Deceleration calculation means,
When the monitor point is in a predetermined range immediately before the intrusion prohibition area from the intrusion prohibition area, the command current value calculated by the deceleration calculation means is changed to a low current value that completely stops the front device, and the electric current is changed. And a signal reduction processing means for outputting to the pressure reducing valve.

In the present invention configured as described above, when the monitor point approaches the intrusion prohibited area and the distance between the monitor point and the intrusion prohibited area decreases, the deceleration calculation means decreases the command current as the distance decreases. When the monitor point enters a predetermined range immediately before the intrusion prohibition area, the signal reduction processing unit changes the command current value calculated by the deceleration calculation unit to a low current value that completely stops the front device, and then the electric value is reduced. Output to the pressure reducing valve. As a result, when the monitor point approaches the predetermined range immediately before the intrusion prohibited area, the command current value output to the electric pressure reducing valve becomes a low current value that completely stops the front device, and the electric pressure reducing valve is closed. The front equipment is stopped. Further, since the electric pressure reducing valve is closed, it is possible to suppress the generation of pilot surge pressure even if the operating lever is subsequently moved, and it is possible to prevent accidental operation of the hydraulic actuator. No more jumping out into the no-entry zone or shock.

[0012] Preferably, the signal reduction processing means performs a hysteresis calculation that lengthens the distance of the predetermined range when the monitor point moves away from the intrusion prohibition area rather than when the monitor point approaches the intrusion prohibition area.

By thus performing the hysteresis calculation in the signal reduction processing means, when the command current value is lowered to a low current value and stopped just before the entry prohibition area as described above, the front device 1A is at this position. Even if it shakes, the front device 1A can be surely kept stopped.

Further, preferably, the signal reduction processing means drops the command current value calculated by the deceleration calculation means to the low current value stepwise. As a result, the front device can be reliably stopped.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention applied to a hydraulic excavator will be described below with reference to FIGS. It should be noted that the present embodiment relates to a case where upper range limitation control is performed.

In FIG. 1, a hydraulic excavator to which the present invention is applied includes a hydraulic pump 2, a boom cylinder 3a driven by pressure oil from the hydraulic pump 2, an arm cylinder 3b, a bucket cylinder 3c, a swing motor 3d and A plurality of hydraulic actuators including the left and right traveling motors 3e and 3f, and a plurality of operating lever devices 4a to 4 provided corresponding to the hydraulic actuators 3a to 3f, respectively.
f, the hydraulic pump 2 and the plurality of hydraulic actuators 3a to
3f, a plurality of flow control valves 5a controlled by operation signals of the operation lever devices 4a to 4f to control the flow rate of pressure oil supplied to the hydraulic actuators 3a to 3f.
And a relief valve 6 that opens when the pressure between the hydraulic pump 2 and the flow control valves 5a to 5f is equal to or higher than a set value, and these are hydraulic drive devices that drive driven members of the hydraulic shovel. Is composed.

Further, as shown in FIG. 2, the hydraulic excavator includes a boom 1a and an arm 1 which rotate in a vertical direction.
articulated front device 1 including b and bucket 1c
A and a vehicle body 1B including an upper swing body 1d and a lower traveling body 1e, and a base end of a boom 1a of the front device 1A is supported by a front portion of the upper swing body 1d. Boom 1
a, an arm 1b, a bucket 1c, an upper swing body 1d, and a lower traveling body 1e are driven members respectively driven by a boom cylinder 3a, an arm cylinder 3b, a bucket cylinder 3c, a swing motor 3d, and left and right traveling motors 3e, 3f. And their operations are instructed by the operation lever devices 4a to 4f.

The operation lever devices 4a to 4f output pilot pressure as operation signals, and the corresponding flow control valves 5a to 5f.
This is a hydraulic pilot system called a pilot operating device for driving f, and as shown in FIG. 3, an operating lever 40 and an operating lever 4 operated by an operator, respectively.
The pressure reducing valve 4 is composed of a pair of pressure reducing valves 41 and 42 that generate a pilot pressure according to the operation amount of 0 and the operation direction.
1, 42 are connected to the pilot pump 43 on the primary port side and pilot lines 44a, 44 on the secondary port side.
b; 45a, 45b; 46a, 46b; 47a, 47
b; 48a, 48b; 49a, 49b via corresponding hydraulic drive units 50a, 50b; 51a, 51 of the flow control valve.
b; 52a, 52b; 53a, 53b; 54a, 54
b; connected to 55a and 55b.

For example, a pilot operating device 4a for a boom
When the operating lever 40 is operated in the direction A of FIG. 3, the pilot source pressure from the pilot pump 43 is reduced.
The pressure of the flow control valve 5a is changed to a pressure proportional to the operation amount of the operation lever 40 and output to the pilot line 44a, and this pressure is applied to the hydraulic drive unit 50a of the flow control valve 5a. Moved towards.
As a result, the pressure oil from the hydraulic pump 2 that is the main pump is supplied to the bottom side of the boom cylinder 3a, the boom cylinder 3a is driven to extend, and the boom 1a shown in FIG. 2 is moved upward. Move the operating lever 40 to B in FIG.
When operated in the direction, the pilot source pressure from the pilot pump 43 is changed to a pressure proportional to the operation amount of the operation lever 40 by the pressure reducing valve 42 and output to the pilot line 44b, and this pressure is output to the hydraulic drive unit of the flow control valve 5a. As shown in FIG. 1, the spool of the flow control valve 5a is supplied to 50b.
Of the hydraulic pump 2 is supplied to the rod side of the boom cylinder 3a.
Is driven to contract, and the boom 1a shown in FIG. 2 is moved downward. When the operating lever 40 is returned to the central position, the pressure reducing valves 41 and 42 are set in the pilot lines 44a and 44.
b is connected to the tank, the application of pilot pressure to the flow control valve 5a is released, the flow control valve 5a is returned to the neutral position by the restoring spring, and the movement of the boom 1a is stopped.
Pilot operation devices 4b, 4c for arms and buckets
The same applies to. By operating the boom, arm, and bucket pilot operating devices 4a to 4c individually or in an appropriate combination, the front device 1A is bent and bent in a desired manner to perform excavation and loading work. be able to. In the specification of the present application, the pilot pressure output from the pilot operating devices 4a and 4b is particularly referred to as "operating pilot pressure".

The hydraulic excavator as described above is provided with the work range limiting control device according to this embodiment. This work range limiting control device has a setting device 7 for indicating an area (prevention area) in which the front member should not enter in advance according to work, a boom 1a, an arm 1b, and a bucket 1.
The front device 1A is provided at each rotation fulcrum of c.
The angle detectors 8a, 8b, 8c for detecting the respective rotation angles as state quantities relating to the position and the posture of the robot, the setting signal of the setter 7, and the detection signals of the angle detectors 8a, 8b, 8c are input to the front member. A control unit 9 that sets an intrusion-prohibited area that must not intrude and outputs an electric signal for limiting and controlling the work range according to the intrusion-inhibited area.
And pilot lines 44a, 44b, 45a, 45b
Proportional solenoid valve 10a, which is installed in each of the pilot operating devices 4a and 4b, uses the operating pilot pressure as a pilot primary pressure to reduce the pressure in accordance with each electric signal output from the control unit 9, and outputs the pressure.
It is composed of 10b, 11a and 11b.

Proportional solenoid valves 10a, 10b, 11a, 11
Reference numeral b is an electric pressure reducing valve, which has a structure as shown in FIG. In the figure, 150 is an input port, 151 is an output port, 152 is a tank port, 153 is a spool, 154
Is an internal passage, 155 is a pressure chamber, 156 is a solenoid, and the pilot operating devices 4a and 4b are connected to the input port 150.
The operation pilot pressure output from the control valve is introduced as the pilot primary pressure, and the pilot secondary pressure (output pressure) from the output port 152 is applied to the hydraulic drive unit 50 of the flow control valves 5a and 5b.
a, 50b; 51a, 51b, solenoid 1
An electric signal from the control unit 9 is given to 56.

When the current value of the electric signal applied to the solenoid 156 is zero, no electromagnetic force is generated in the solenoid 156, and the urging force Fp by the pilot primary pressure transmitted to the pressure chamber 155 through the internal passage 154 causes The spool 154 moves to the right in the drawing, the output port 151 communicates with the tank port 152, and the pilot secondary pressure becomes the tank pressure (full close). When the current value of the electric signal applied to the solenoid 156 is not zero, an axial force Fs corresponding to the current value is generated, the spool 153 is moved to the left in the drawing, and the biasing force Fp applied by the pressure chamber 155 is generated.
The spool 153 stops at the balanced position. At this time, the communication between the output port 151 and the tank port 152 is cut off, the output port 151 communicates with the input port 150 through the throttle, and the output port 151 is depressurized in accordance with the throttle. Output as pilot secondary pressure. Further, the depressurized pressure (pilot secondary pressure) of the output port 151 is introduced into the pressure chamber 155 through the internal passage 154, and the biasing force Fp has a value corresponding to the pilot secondary pressure. And the solenoid 156
The current value of the electric signal given to the
When s becomes larger, the spool 153 is moved to the left in the figure accordingly, the throttle of the spool 153 becomes weaker, the degree of pressure reduction becomes smaller, and the pressure (pilot secondary pressure) generated at the output port 151 increases. Solenoid 156
When the electric current value of the electric signal given to (1) becomes maximum, the spool 153 is moved to a position where the throttle does not work (full open), and the pressure (pilot secondary pressure) generated at the output port 151 becomes the pressure at the input port 150 ( Pilot primary pressure).

The setting device 7 outputs a setting signal to the control unit 9 by operating means such as a switch provided on the operation panel or the grip to instruct the setting of the intrusion prohibition area, and the display device is displayed on the operation panel. Etc., there may be other auxiliary means. Other methods such as a method using an IC card, a method using a barcode, a method using a laser, and a method using wireless communication may be used.

The control unit 9 has a control function as shown in FIG. That is, the control unit 9 includes an intrusion prohibition area calculation unit 9a, a front attitude calculation unit 9b, a limit value storage memory 9c, a monitor point selection calculation unit 9d, a deceleration control calculation unit 9e, a maximum cylinder speed calculation unit 9f, and a maximum pilot pressure calculation. 9g, valve command current value calculator 9h,
The valve command signal reduction processing operation unit 9i and the current output unit 9j have respective functions.

The intrusion-prohibited area calculation unit 9a performs setting calculation of an area (intrusion-prohibited area) in which the front member should not intrude in response to an instruction from the setting device 7. One example will be described with reference to FIG.

In FIG. 6, the rear end of the arm 1b is moved to a point Pc on the height at which the operator wants to limit the rear end, and the position of the rear end of the arm 1b at that time is calculated by an instruction from the setter 7. The position is set as the set value of the boundary of the intrusion prohibited area. Here, the position of the point Pc is calculated by the front posture calculation unit 9b.

In the front attitude calculation unit 9b, the rotation angles of the boom, arm and bucket detected by the angle detectors 8a to 8c and the front device 1A and the front device 1A as shown in FIG. Dimensions L of body 1B
The position and orientation of the front device 1A are calculated using the data of 1, L2, L3, L4, L5 and the like. At this time, the position and orientation are, for example, XZ with the rotation fulcrum of the boom 1a as the origin.
Obtained as coordinate values of the coordinate system. The XZ coordinate system is an orthogonal coordinate system in a vertical plane fixed to the main body 1B.

Here, when performing the setting calculation in the intrusion-prohibited area calculation unit 9a, the front attitude calculation unit 9b calculates the position of the point Pc as the Z coordinate value of the XZ coordinate system, and the calculated value is the intrusion-prohibited area. The boundary set value (Z coordinate value = Pcz) is used. The set value (Z coordinate value = Pcz) of the boundary of the intrusion prohibition area calculated by the intrusion prohibition area calculation unit 9a is stored in the limit value storage memory 9c.

Further, a plurality of monitor points M1 and M2 are set in advance at predetermined positions on the front device 1A, and the front posture calculation section 9b calculates the positions of the monitor points M1 and M2 during the work by the restriction control. doing. In this embodiment, the monitor point M1 is the arm 1
It is the rear end of b, and the monitor point M2 is the bucket 1c.
Is the highest point of a circle having a radius L3 (distance from the bucket pin to the tip of the bucket) centered on the rotation center (bucket pin) of. Also at this time, the position of each monitor point is XZ
Obtained as the value of the coordinate system, and the height of each monitor point is X
It is calculated as the Z coordinate value of the Z coordinate system.

Here, the position of the rear end of the arm 1b calculated by the front posture calculation unit 9b, that is, the position of the monitor point M1 (M1x, M1z) and the position of the monitor point M2 (M2x, M2z) are the rotation angles. From α, β, γ, the size of each part shown in FIG. 6 stored in the storage device is used to obtain the following equation.

M1x = L1cosα-L4cos (α + β)
+ L5sin (α + β) M1z = -L1sinα + L2sin (α + β) + L5co
s (α + β) M2x = L1 cos α + L2 cos (α + β) M2z = −L1 sin α−L2 sin (α + β) + L3 In the monitor point selection unit 9d, the Z coordinate values M1z and M2z of the monitor points M1 and M2 calculated by the front posture calculation unit 9b, Distances L1M, L between the monitor points M1, M2 and the boundary of the intrusion prohibition area from the set value Pcz of the boundary of the intrusion prohibition area stored in the limit value storage memory 9c.
Calculate 2M, compare the distances L1M and L2M, and select the monitor point closer to the intrusion prohibition area, that is, if L1M <L2M, select M1 and if L1M> L2M, select M2 and set it as the selected monitor point Ms. . If L1M = L2M, either one may be selected as the monitor point, but here, M
1 is the selected monitor point.

In the deceleration control calculation unit 9e, the Z coordinate value Msz of the monitor point Ms selected by the monitor point selection unit 9d, the set value Pcz of the boundary of the intrusion prohibited area stored in the limit value storage memory 9c, and the control unit. The extension direction and the contraction direction of the boom cylinder 3a and the extension of the arm cylinder 3b based on the distance (hereinafter referred to as deceleration distance) LU and the deceleration function (to be described later) indicating the range of the deceleration area stored in the storage device 9 in advance. The deceleration command signals KBU, KBD, KAU, KAD for the direction and the contraction direction are calculated. The contents of this calculation will be described below.

First, the distance LM between the selected monitor point Ms and the boundary of the intrusion prohibited area is calculated. In FIG. 6, assuming that the monitor point M1 is at the highest position, the distance LM
Has been calculated. Next, this distance LM and deceleration distance LU
, And if LM> LU, select monitor point M
Since s has not entered the deceleration area, the deceleration command signal KB
U, KBD, KAU, KAD are all set to 1. If LM ≦ LU, it is determined that the selected monitor point Ms is in the deceleration area, and the deceleration command signals KBU, KBD,
Calculate KAU and KAD.

KBU = LM / LU KBD = 1 KAU = LM / LU KAD = LM / LU The above deceleration function is shown in FIG. As can be seen from the figure, the deceleration function of the deceleration command signal KBU for the extension direction of the boom cylinder 3a and the deceleration function of the deceleration command signals KAU, KAD for the extension and contraction directions of the arm cylinder 3b are less than the deceleration distance LU and the distance LM. The deceleration command signal is set to linearly decrease from 1 to 0 as becomes smaller.

In the maximum cylinder speed calculation unit 9f, the maximum cylinder speed VBU in the extension direction and the contraction direction of the boom cylinder 3a stored in advance in the storage device of the control unit 9 is stored.
max, VBDmax, maximum cylinder speeds VAUmax, VADmax in the extension and contraction directions of arm cylinder 3b, and deceleration command signals KBU, KBD and KAU, KAD calculated above, and maximum cylinder speeds for deceleration and expansion of boom cylinder 3a VBUmaxc, VBDmaxc and the deceleration maximum cylinder speeds VAUmaxc, VADmaxc for the expansion and contraction of the arm cylinder 3b are calculated. This arithmetic expression is shown below.

VBUmaxc = KBU × VBUmax VBDmaxc = KBD × VBDmax VAUmaxc = KAU × VAUmax VADmaxc = KAD × VADmax In the maximum pilot pressure calculation unit 9g, the deceleration maximum cylinder speeds VBUmaxc and VBD calculated in the maximum cylinder speed calculation unit 9f
Booms from maxc, VAUmaxc, VADmaxc and pilot pressure and cylinder speed tables as shown in FIGS. 8 (a), (b), (c) and (d) stored in the storage unit of the control unit 9 in advance. Maximum deceleration pilot pressures PBUmaxc and PBDmaxc for cylinder 3a expansion and contraction, and maximum deceleration pilot pressure PAUma for arm cylinder 3b expansion and contraction.
Calculate xc and PADmaxc.

In the valve command current value calculator 9h, PBUmaxc, PBDmaxc, P calculated by the maximum pilot pressure calculator 9g
Based on AUmaxc, PADmaxc and the pilot pressure and current value table stored in advance in the storage device of the control unit 9 as shown in FIG.
The command current values iBU, iBD, iAU, iAD for the proportional solenoid valves 10a, 10b, 11a, 11b that define the speeds of expansion and contraction of the arm cylinder 3b are calculated.

In the valve command signal reduction processing operation unit 9i,
Command current value i calculated by the valve command current value calculation unit 9h
For BU, iBD, iAU, and iAD, signal reduction processing involving hysteresis calculation is performed using a table as shown in FIG. Here, the signal reduction process with hysteresis will be described.

In FIG. 10, the horizontal axis indicates the command current value iBU,
iBD, iAU, iAD, the vertical axis is the command current value iBU, iB
Command current value iBU after signal reduction processing of D, iAU, iAD
C, iBDC, iAUC, iADC. Further, i0 is a command current value when the deceleration command signal KBU = 0, KBD = 0, KAU = 0, KAD = 0 when the selected monitor point Ms reaches the intrusion prohibited area. The following description describes the signal reduction process in the boom cylinder extension direction (iBU).

First, when one of the monitor points closest to the intrusion prohibition area, that is, the selected monitor point Ms is far away from the intrusion inhibition area, a flag indicating the history of the current value when the signal reduction processing is performed. flg to f
With lg = 0, the command current value iBUC is set to the same value as the command current value iBU calculated by the valve command current value calculator 9h (iBUC = iBU). Next, the selected monitor point Ms gradually approaches the intrusion prohibited area, and the command current value iBU calculated by the valve command current value calculation unit 9h reaches the command current value i0 when the selected monitor point Ms reaches the intrusion prohibited area. If it becomes smaller than i1 which is larger than i1, the command current value iBUC is set to flg = 1 and the low current value i0 'smaller than i0 is set (iB
UC = i0 '). On the contrary, a selected monitor point Ms closest to the intrusion prohibition area among the monitor points gradually moves away from the intrusion prohibition area, and the valve command current value calculation unit 9
The command current value iBU calculated by h gradually increases, i
When BU becomes i2 which is larger than the above current value i1, flg = 0
And iBUC = i2. Until then, iBUC with flg = 1.
Let C = i0 '.

That is, if iBU is smaller than i1, fl
When g = 1, iBUC = i0 '. If iBU is larger than i2, then flg = 0 and iBUC = iBU. If iBU is between i1 and i2, either i0 'or iBU will be selected according to flg (if flg = 0, iBUC = iB
If U and flg = 1, then iBUC = i0 ').

In this way, the selected monitor point Ms
However, when the command current value iBU is within the predetermined range immediately before the intrusion prohibited area where the command current value iBU is i1 or less, the signal reduction processing is performed to set the command current value iBUC to a low current value i0 'smaller than i0. Further, the selected monitor point Ms is located farther from the intrusion prohibition area when the command current value iBU becomes i1 than when the instruction current value iBU becomes i1, and the intrusion prohibition area is more than when the selected monitor point Ms approaches the intrusion prohibition area. A hysteresis calculation is performed in which the command current value iBUC is set to a low current value i0 'when the distance is longer than a predetermined range.

The same applies to the hysteresis low current conversion calculation in the arm cylinder extension direction (iAU) and the contraction direction (iAD). For the direction of contraction of the boom cylinder, refer to i
BDC is always set to the same value as the command current value iBU calculated by the valve command current value calculator 9h (iBDC = iBD).

In the current output unit 9j, iBUC, iBDC, iAUC, iA calculated by the valve command signal reduction processing operation unit 9i.
DC is amplified by an amplifier (not shown) and output as an electric signal to the proportional solenoid valves 10a, 10b, 11a, 11b.

Here, the deceleration command signals calculated by the deceleration control calculator 9e are KBU = 1, KBD = 1, KAU = 1, KAD =
When it is 1, deceleration maximum pilot pressures PBUmaxc, PBDmaxc, PAUmaxc, P calculated by the maximum pilot pressure calculation unit 9g
ADmaxc is set to the maximum operating pilot pressure (pilot pump source pressure) and the deceleration maximum pilot pressure PBU
Command current values iBU, iBD, iAU, i when maxc, PBDmaxc, PAUmaxc, PADmaxc are set to the maximum pilot pressure
AD is a current value for fully opening the proportional solenoid valves 10a, 10b, 11a, 11b. Also, KBU = 0, KBD =
When 0, KAU = 0, KAD = 0, the deceleration maximum pilot pressures PBUmaxc, PBDmaxc, PAUmaxc, PADmaxc are set to 0, and the command current values iBU, iBD, iAU, i at this time are set.
AD is a current value at which the proportional solenoid valves 10a, 10b, 11a, 11b are fully closed (a current value at which the cylinders 3a, 3b do not operate). The low current value i0 'is KBU = 0, KB
Since it is smaller than iO when D = 0, KAU = 0, KAD = 0, the proportional solenoid valves 10a, 10b, 11a, 11b are surely fully closed (the operation of the cylinders 3a, 3b is stopped), and the cylinders are closed. It is a current value that surely stops the front device 1A. As an example, a low current value i
0'is 0 milliamps.

The flow of the above control is shown as a flow chart in FIG.

In FIG. 11, steps 400 and 410 correspond to the front attitude calculating section 9b, and steps 200 and 500,
510 corresponds to the monitor point selection calculation unit 9d, steps 600 to 630 correspond to the deceleration control calculation unit 9e, step 700 corresponds to the maximum cylinder speed calculation unit 9f, and step 8
00 to 820 correspond to the maximum pilot pressure calculation unit 9g,
The procedure 900 corresponds to the valve command current value calculation unit 9h, the procedure 1000 corresponds to the valve command signal reduction processing calculation unit 9i, and the procedure 1100 corresponds to the current output unit 9j. In addition,
Procedure 300 is an initial setting for safety.

In the above, the proportional solenoid valve 10a,
10b or 11a, 11b are pilot operating devices 4a,
4b and at least one flow control valve 5a corresponding thereto
Or 5b, which constitutes an electric pressure reducing valve that reduces the pressure of the operating pilot pressure output from the pilot operating device 4a or 4b according to the command current value and outputs the pressure. 9b, limit value storage memory 9c, monitor point selection calculation unit 9d, deceleration control calculation unit 9e, maximum cylinder speed calculation unit 9f, maximum pilot pressure calculation unit 9g, valve command current value calculation unit 9h, monitor point Ms and entry prohibition. The valve command signal reduction processing calculation unit 9i and the current output unit 9j of the control unit 9 constitute a deceleration calculation unit that calculates a command current value that decreases as the distance to the region decreases.
And a signal reduction processing means for converting the command current value into a low current value for completely stopping the front device and outputting the electric current to the electric pressure reducing valve when is in a predetermined range immediately before the intrusion prohibition area. To do.

Further, the valve command signal reduction processing operation unit 9i constituting the signal reduction processing means has a hysteresis that makes the distance of the predetermined range longer when the monitor point Ms moves away from the intrusion prohibited area than when it approaches the intrusion prohibited area. The calculation is performed.

Next, the operation of this embodiment configured as described above will be described. When the operator operates the operation levers of the boom and arm pilot operating devices 4a and 4b in the boom raising direction and the arm dumping direction, respectively, in an attempt to move the front device 1A upward, the boom raising side pilot line 44a and the arm dumping side. The operating pilot pressure is generated in the pilot line 45b of the boom 1 and the hydraulic control valves 5a and 5b are driven, and the boom 1 that is the front member is generated.
a and the arm 1b are moved. Boom 1a, arm 1
The joint angles of b and the bucket 1c are detected by angle detectors 8a to 8c, which are position detecting means, and the detection signals are input to the front attitude calculation unit 9b of the control unit 9.
The front attitude calculator 9b calculates the positions of the monitor points M1 and M2 based on this input signal, and the monitor point selector 9d calculates the Z coordinate values M1z and M2z of the monitor points M1 and M2 calculated by the front attitude calculator 9b.
And the set value Pcz of the boundary of the intrusion prohibited area stored in the limit value storage memory 9c, the distances L1M and L2M between the monitor points M1 and M2 and the boundary of the intrusion prohibited area are calculated,
The monitor point closer to the intrusion prohibition area is set as the selected monitor point Ms.

The deceleration control calculator 9e selects from the Z coordinate value Msz of the monitor point Ms selected by the monitor point selector 9d and the set value Pcz of the boundary of the intrusion prohibited area stored in the limit value storage memory 9c. Calculate the distance LM between the monitor point Ms and the boundary of the intrusion prevention area,
This distance LM is compared with the deceleration distance LU to determine whether the selected monitor point Ms is in the deceleration area.

At this time, when the front device 1A has not risen high and the selected monitor point Ms is far from the intrusion prohibited area, LM> LU, so that the deceleration control calculation unit 9e determines that the selected monitor point Ms is in the deceleration area. It is judged that it has not entered, KBU = 1, KBD = 1, KAU = 1, K
Generates a deceleration command signal with AD = 1.

In the valve command signal reduction processing operation unit 9i,
The flag flg indicating the history of the current value is set to flg = 0, and i
BUC = iBU, iBDC = iBD, iAUC = iAU, iADC = iAD are calculated, and proportional solenoid valves 10a, 10b, 11a, 11 are calculated.
Fully open b. As a result, the operating pilot pressure generated by the pilot operating devices 4a and 4b is directly transmitted to the boom hydraulic control valve 5a and the arm hydraulic control valve 5b, and the front device 1A can be moved as the operator operates. .

When the front monitor 1A approaches the intrusion prohibition area and the selected monitor point Ms reaches the deceleration area, the deceleration control calculation section 9e determines that LM≤LU, so it is determined that the selected monitor point Ms has entered the deceleration area and the distance LM Accordingly, deceleration command signals KBU, KAU, KAD smaller than 1 are generated from the deceleration function shown in FIG. 7, proportional solenoid valves 10a, 11a, 11b are throttled according to the deceleration command signal, and the operating speeds of the boom and arm are reduced. To be

When the front device 1A further approaches the intrusion prohibition area and the command current values iBU, iAU, iAD calculated by the valve command current value calculation unit 9h become i1, the valve command signal reduction processing calculation unit 9i With flg = 1, the command current values iBUC, iAUC, iADC are set to iBUC = i0 ′, iAUC = i
0 ', iADC = i0', proportional solenoid valves 10a, 11a,
11b is fully closed, the movements of the boom cylinder 3a and the arm cylinder 3b are stopped, and the front device 1A is stopped.

When the operator further operates the operation levers of the boom and arm pilot operating devices 4a and 4b in the boom raising direction and the arm dumping direction with the front device 1A thus stopped, the boom raising side The operating pilot pressure is generated again in the pilot line 44a and the pilot line 45b on the arm dump side. However, at this time, since the proportional solenoid valves 10a and 11b are fully closed by the signal reduction processing in the calculation unit 9i as described above, surge pressure does not rise on the output side of the proportional solenoid valves 10a and 11b, and the flow rate is reduced. The control valves 5a and 5b do not momentarily move according to the surge pressure, and the boom cylinder 3a and the arm cylinder 3b do not move.

Now, this will be further described with reference to FIGS. 12 and 13.

FIG. 12 shows the valve command current value calculation unit 9h until the front device 1A approaches the inaccessible area and stops.
4 shows the relationship between the command current values iBU, iBD, iAU, iAD (represented by i) calculated in step 1 and the corresponding cylinder speed when the pilot operating device is operated by an arbitrary amount.

When the front device 1A approaches the intrusion prohibition area and the command current values iBU and iAD calculated by the valve command current value calculation unit 9h become i1, the valve command signal reduction processing calculation unit 9i of the present invention performs signal reduction processing. If not performed, the currents corresponding to the command current values iBU, iAD are directly applied to the proportional solenoid valves 10a, 11b, and the boom cylinder 3
a and the arm cylinder 3b move at a speed of v1, and the front device 1A moves while being decelerated.

When the deceleration control is performed in this way, the operating speed of the boom and the arm is considerably slowed immediately before the intrusion prohibited area, so the operator sets the operation lever to the neutral position before the front device 1A completely stops. The operation pilot pressure output from the pilot operating devices 4a and 4b may be returned to zero and the front device 1A may be stopped. In such a stopped state, the command current values iBU, iAD calculated by the valve command current value calculation unit 9h have not dropped to the current value i0 that completely stops the front device 1A, and the proportional solenoid valves 10a, 11b are slightly reduced. Open to, for example, several Kg /
It is ready to output a hydraulic pressure of about cm ² . The command current values iBU and iAD in this state are set to is, and the proportional solenoid valve 10
Let Ps be the hydraulic pressure that can be output by a and 11b.

In this state, when the operator again operates the operating lever to move the boom in the direction closer to the intrusion prohibition area and establishes the operation pilot pressure, the proportional solenoid valves 10a and 11b are instantaneously changed due to the hydraulic pressure response delay. The operating pilot pressure cannot be reduced to Ps and the proportional solenoid valves 10a, 11
The surge pressure rises for a short time depending on the open state of b. This state is shown in FIG. When the surge pressure rises in this way, the flow control valves 5a and 5b momentarily move according to the surge pressure, and the boom cylinder 3a and the arm cylinder 3b slightly move. For this reason,
Although the boom and arm should have stopped for the operator, the boom and arm move again due to subsequent lever operations, and depending on the magnitude of the surge pressure, the front device may enter from the set intrusion prohibition area. You have to be careful. Further, when the boom moves due to the surge pressure, some shock is accompanied, which makes the operator uncomfortable.

In this embodiment, the command current values iBU, iAU, calculated by the valve command current value calculation unit 9h as described above are used.
When the front device 1A approaches the entry prohibition area to the distance where iAD becomes i1, the proportional solenoid valves 10a, 11a, 11b are set in the valve command signal reduction processing operation unit 9i as iBUC = i0 ', iAUC = i0', iADC = i0 '. Is forcibly fully closed, the movements of the boom cylinder 3a and the arm cylinder 3b are stopped, and the front device 1A is stopped. Thereafter, the operator further operates the operation lever to operate the pilot line 4
Even if the operating pilot pressure is set up in 4a and 45b,
The surge pressure as shown in (1) does not rise, and the boom cylinder 3a and the arm cylinder 3b do not move carelessly and the front device 1A does not enter the entry prohibited area. Moreover, the operator is not made uncomfortable due to the shock caused by the surge pressure.

Further, as described above, in the valve command signal reduction processing operation unit 9i, iBUC = i0 ', iAUC = i0', iADC =
When the front device 1A is stopped as i0 ', the front device 1A may sway due to the vibration of the vehicle body at the stopped position. In this case, the shaking is caused by the angle detector 8
a to 8c, and the valve command current value calculator 9h of the control unit 9 controls the command current values iBU and iAD of i1 or more.
Is calculated, if there is no hysteresis calculation in the valve command signal reduction processing calculation unit 9i, the command current values iBU, iAD
Is converted to iBUC, iADC as it is, and the proportional solenoid valve 10
The a and 11b are opened again, and the boom cylinder 3a and the arm cylinder 3b start moving again. In the present embodiment, the valve command signal reduction processing calculation unit 9i performs a hysteresis calculation, and the command current values iBU and iAD are i2 larger than i1.
Since the command current values iBUC and iADC are kept at i0 'until the above, the proportional solenoid valve 10 is operated even if the front device 1A shakes and the shake is detected by the angle detectors 8a to 8c.
The boom cylinder 3a and the arm cylinder 3b do not start to move again, and the front device 1A can be reliably stopped.

As described above, according to the present embodiment, when the front device 1A approaches the entry prohibited area, the operating speed of the cylinder is gradually reduced, and the operating speed of the cylinder becomes zero immediately before the entry prohibited area. The device 1A does not enter the prohibited area. Further, since the valve command current values iBUC and iADC are dropped to a low current value i0 'smaller than the current value i0 at which the cylinder does not operate in the predetermined range immediately before the entry prohibition region, the front device 1A is set in the predetermined range immediately before the entry prohibition region.
After stopping, the generation of pilot surge pressure can be suppressed even if the operation lever is largely moved, and inadvertent operation of the boom cylinder 3a and the arm cylinder 3b can be prevented. For this reason, it is possible to prevent the front device from popping out and entering the entry-prohibited area, or causing a shock to give an operator discomfort.

Further, since the hysteresis calculation is performed in the signal reduction process immediately before the entry prohibition area, the command current values iBUC, iADC
Even if the front device 1A shakes in a state where the current is dropped to a low current value i0 ′ and the front device 1A is stopped immediately before the entry prohibition area, the front device 1A can be surely kept stopped.

The work range limiting control device of the present invention is not limited to the above-described embodiment, and various modifications can be made.
As an example, a goniometer that detects a rotation angle is used as a means for detecting a state quantity related to the position and orientation of the front device 1A, but a stroke of a cylinder may be detected. Although the case where the intrusion prohibition area is set to the upper side has been described, the same applies to the case where the intrusion prohibition area is set to the lower side and the front side.

Further, the valve command signal reduction processing operation unit 9i
Then, although the signal reduction process accompanied by hysteresis is performed, the hysteresis calculation can be omitted depending on the situation such as setting a long distance in a predetermined range from the position where the command current value iBU becomes i1 to the intrusion prohibited area. Furthermore, the command current value iBU is i
When it becomes 1 or less, the command current value iBUC is stepwise reduced to the low current value i0 ', but it may be reduced with a certain inclination instead of stepwise. In order to reliably swing the proportional solenoid valve, the command current value iBUC is set to i
Although it is reduced to 0 ', it may be reduced to i0.

[0068]

According to the present invention, when the front device is stopped immediately before the preset entry prohibited area, the actuator is inadvertently moved by the subsequent lever operation and the front device enters the entry prohibited area. Or, it is possible to prevent a shock from being generated and giving an operator discomfort.

Further, according to the present invention, even if the front device shakes at the stop position immediately before the entry prohibited area, the front device can be surely kept stopped.

[Brief description of the drawings]

FIG. 1 is a diagram showing a work range limiting control device for a construction machine according to an embodiment of the present invention together with a hydraulic drive device.

FIG. 2 is a diagram showing the appearance of a hydraulic shovel to which the present invention is applied.

FIG. 3 is a view showing a configuration of a hydraulic pilot type operation lever device.

FIG. 4 is a diagram showing a structure of a proportional solenoid valve.

FIG. 5 is a functional block diagram showing a control function of the control unit of the present embodiment.

FIG. 6 is a diagram showing a coordinate system used in the work range restriction control of the present embodiment, a method of setting an entry prohibition region, and a deceleration region.

FIG. 7 is a diagram showing a relationship between a deceleration command signal and a distance between a monitor point and an intrusion prohibition area in deceleration control calculation.

FIG. 8 is a diagram showing a relationship between a pilot pressure and a cylinder speed in a maximum pilot pressure calculation unit.

FIG. 9 is a diagram showing a relationship between a pilot pressure in a valve command current value calculation unit and a current value output to a proportional solenoid valve.

FIG. 10 is a diagram showing a relationship between input and output current values of signal reduction processing accompanied by hysteresis calculation in a valve command signal reduction processing calculation unit.

FIG. 11 is a flowchart showing the processing contents of the control unit.

FIG. 12 is a diagram showing a relationship between a command current value and a cylinder speed immediately before an entry prohibition region.

FIG. 13 is a diagram showing a surge pressure caused by a response delay of a proportional solenoid valve.

[Explanation of symbols]

 1A Front device 1B Vehicle body 1a Boom 1b Arm 1c Bucket 2 Hydraulic pump 3a Boom cylinder 3b Arm cylinder 4a to 4f Operating lever device 5a to 5f Flow control valve 7 Setting device 8a to 8c Angle detector 9 Control unit 9a Intrusion prohibition area computing unit 9b Front posture calculation unit 9c Limit value storage memory 9d Monitor point selection calculation unit 9e Deceleration control calculation unit 9f Maximum cylinder speed calculation unit 9g Maximum pilot pressure calculation unit 9h Valve command calculation unit 9i Valve command signal reduction processing calculation unit 9j Current output unit 10a-11b Proportional solenoid valve (electric pressure reducing valve) 50a-55b Hydraulic drive unit

Claims (3)

[Claims] 1. A multi-joint type front device composed of a plurality of vertically rotatable front members, a plurality of hydraulic actuators for driving the plurality of front members, and an operation of the plurality of front members. A plurality of operation means for instructing, and a plurality of flow rate control valves that are driven according to the operation of the plurality of operation means and that control the flow rate of the pressure oil supplied to the plurality of hydraulic actuators. The means is provided in a construction machine, which is a plurality of pilot operating devices that output operating pilot pressures and drives corresponding flow control valves, and is provided at a distance between a preset monitor point and a preset intrusion prohibition area for the front device. According to the calculation, the command current value is calculated and output, and when the monitor point approaches the intrusion prohibition area, the front device is decelerated and the intrusion prohibition is performed. In a work range limitation control device for a construction machine, which stops the front device when reaching a stop region, the pilot operation device is provided between at least one of the plurality of pilot operating devices and a plurality of flow control valves corresponding thereto. An electric pressure reducing valve that reduces and outputs the operation pilot pressure output from the device according to the command current value, and the command current value is calculated so that it decreases as the distance between the monitor point and the intrusion prohibited area decreases. Deceleration calculating means for controlling, and a low current for completely stopping the front device with the command current value calculated by the deceleration calculating means when the monitor point is in a predetermined range immediately before the intrusion prohibited area from the intrusion prohibited area. And a signal reduction processing means for changing the value and outputting it to the electric pressure reducing valve. Limit controller. 2. The work range limitation control device for a construction machine according to claim 1, wherein the signal reduction processing means is more distant from the intrusion prohibition area than when the monitor point is closer to the intrusion prohibition area. A work range limitation control device for a construction machine, which performs a hysteresis calculation for lengthening a distance within a predetermined range. 3. The work range limiting control device for a construction machine according to claim 1, wherein the signal reduction processing means drops the command current value calculated by the deceleration calculation means to the low current value in a step-like manner. A control device for limiting the working range of construction machinery.