JPH0995967A - Control device for operation range limit of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly decrease the speed of an actuator so as to stop by providing an electric pressure reducing valve, a pressure detector, a deceleration computing part and an output correcting means between at least one of pilot operating devices and a flow control valve corresponding to this. SOLUTION: The invasion prohibition territory of a front member is previously indicated by a setter 7 according to an operation. When a monitor point approaches the prohibition territory and the distance to the prohibition territory becomes small, a first command current value is computed. Meanwhile a second command current value corresponding to pilot primary pressure is computed, and the smaller one of the first and second command current values is output to proportional solenoid valves 10a-11b as an electric signal. When the first command current value approaches the prohibition territory exceeding the distance where the first command current value becomes smaller than the second one, the first command is selected so as to gradually decrease the operating speed of an actuator and reach zero speed, and hence a front device is stopped. Hereby, the actuator can be smoothly stopped.

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, as a characteristic of the electric pressure reducing valve, when the current value is large with respect to the given pilot primary pressure (the operating pilot pressure output from the pilot operating device), the spool is strong on the surface opposite to the solenoid. In many cases, when the spool is pressed and the spool moves to the solenoid side to start depressurization, the spool does not move immediately and the movement of the spool momentarily deteriorates. In this specification, a phenomenon in which the movement of the spool is deteriorated by being pressed against one side is referred to as a "spool adhesion phenomenon". If this phenomenon occurs, no matter how much the current value is lowered and the operation pilot pressure is reduced, the pressure reduction will be delayed for a moment, so the start of deceleration control will be delayed, and it will be the same as the apparent reduction in deceleration distance. In some cases, a large impact is generated when the actuator stops, which makes the operator uncomfortable. Further, when the bucket is loaded, the cargo may be spilled.

An object of the present invention is to provide a work range limiting control device for a construction machine, which can smoothly reduce the speed of the actuator and stop it without being affected by the "spool adhesion phenomenon" of the electric pressure reducing valve. is there.

[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. A construction machine, which is a plurality of pilot operating devices that output pilot pressure and drive corresponding flow control valves, is provided, and the first position is determined according to the distance between a preset monitor point and a preset intrusion prohibition area for the front device. 1 Calculate the command current value, output an electric signal, and decelerate the front device when the monitor point approaches the intrusion prohibited area.
In a work range limiting control device for a construction machine that stops the front device when reaching the intrusion prohibition region, the work range limiting control device is provided between at least one of the plurality of pilot operating devices and a plurality of flow control valves corresponding thereto, The operation pilot pressure output from the pilot operating device is provided as a pilot primary pressure, and is provided between the pilot operating device and the electrical reducing valve, and an electric pressure reducing valve that reduces and outputs the pilot primary pressure according to the electric signal. Detecting means for detecting the pilot primary pressure of the electric pressure reducing valve, deceleration calculating means for calculating the first command current value so as to become smaller as the distance between the monitor point and the intrusion prohibition area becomes smaller, and the detecting means. A second command current value corresponding to the pilot primary pressure of the electric pressure reducing valve detected by the means is calculated, and the first and second commands are calculated. The smaller the current values a configuration and an output correction means for output to the electric pressure reducing valve as the electrical signal.

In the present invention configured as described above, when the monitor point approaches the intrusion prohibition area and the distance between the monitor point and the intrusion prohibition area decreases, the deceleration calculation means decreases as the distance decreases. The command current value is calculated, the output correction means calculates a second command current value corresponding to the pilot primary pressure detected by the detection means, and the smaller one of the first and second command current values is used as an electric signal in the electrical system. Output to pressure reducing valve. As a result, the first command current value is selected when the front device approaches the intrusion prohibition region for a distance that makes the first command current value smaller than the second command current value. The operating speed of the actuator is reduced, and when it reaches the intrusion prohibition area, the operating speed of the actuator becomes zero and the front device stops.

Further, since the second command current value corresponding to the pilot primary pressure is output as an electric signal until the first command current value becomes smaller than the second command current value, the pilot primary pressure of the electric pressure reducing valve is output. On the other hand, the command current value does not become too large, and the spool of the electric pressure reducing valve moves quickly when shifting to the deceleration control as described above, and the influence of the "spool adhesion phenomenon" is mitigated. Therefore, the pressure reducing operation by the electric pressure reducing valve is smoothly performed, and the actuator can be smoothly stopped.

Preferably, the output correction means determines whether the distance between the monitor point and the intrusion prohibition area is less than or equal to a predetermined value, and the determination means determines that the distance is less than or equal to a predetermined value. A value corresponding to the pilot primary pressure detected by the detecting means is calculated as the second command current value, and when the determining means determines that the distance is not less than or equal to a predetermined value, it corresponds to the maximum pressure of the operating pilot pressure. And a calculation means for calculating a value to be used as the second command current value.

With such a configuration, the value corresponding to the maximum pilot pressure is calculated as the second command current value before the distance between the monitor point and the intrusion prohibition area becomes equal to or less than the predetermined value, so that the electric The pressure reducing valve is fully opened, and the front device can be operated without being greatly affected by the resistance of the electric pressure reducing valve.

Further, preferably, the deceleration calculation means performs a calculation to reduce the first command current value when the monitor point reaches a preset deceleration area, and the predetermined value of the distance determined by the determination means is The distance is set to be approximately equal to the deceleration area. With this configuration, the pilot primary pressure follow-up control based on the second command current value is started at the same time when the deceleration control based on the first command current value is started, and when the monitor point is located far from the intrusion prohibited area, the second It is possible to prevent the electric pressure reducing valve from being throttled by the command current value and the pilot primary pressure control from being started immediately before the intrusion prohibition region.

[0016]

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.

Referring to 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 vertically.
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 operating lever devices 4a to 4f output pilot pressure as an operation signal, 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.
Provided on the angle detectors 8a, 8b, 8c for detecting the respective rotation angles as state quantities related to the position and posture of the robot, and on the pilot lines 44a, 44b; 45a, 45b of the boom and arm pilot operating devices 4a, 4b. Pressure detectors 60a, 60b for detecting the operating pilot pressure output from the pilot operating devices 4a, 4b; 61a,
61b, setting signal of the setting device 7, angle detectors 8a, 8
b, 8c and pressure detectors 60a, 60b; 61a, 61
The control unit 9 which inputs the detection signal of b, sets an intrusion prohibited area in which the front member should not intrude, and outputs an electric signal for limiting and controlling the working range in accordance with the intrusion prohibited area, and a pilot. Lines 44a, 44
b, 45a, 45b, respectively. The operation pilot pressures output from the pilot operating devices 4a, 4b are used as pilot primary pressures, which are reduced in accordance with the respective electric signals output from the control unit 9 and output. It is composed of proportional solenoid valves 10a, 10b, 11a, 11b. The pressure detectors 60a, 60b; 61a,
Detecting the operation pilot pressure output from the pilot operating devices 4a, 4b at 61b ultimately detects the pilot primary pressure of the proportional solenoid valves 10a, 10b, 11a, 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 electric 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 is generated. 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 prohibited 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 the intrusion prohibition area calculation unit 9a, the front attitude calculation unit 9b, the limit value storage memory 9c, the deceleration control calculation unit 9d, the maximum cylinder speed calculation unit 9e, the maximum pilot pressure calculation unit 9f, and the valve command calculation unit. 9g, a pilot primary pressure follow-up determination calculation unit 9h, a pilot pressure calculation unit 9i, a valve command calculation unit 9j, a minimum value determination calculation unit 9k, and a current output unit 9m.

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

In FIG. 6, a plurality of monitor points P1 to P5 are set in advance at predetermined locations on the front device 1A, and the operator operates the front device 1A to a desired height, and an instruction from the setting device 7 is given. And the heights P1z to P of the monitor points P1 to P5 at that time
5z is calculated, and the highest value is set as the set value of the boundary of the intrusion prohibited area. Here, the values of P1z to P5z are 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
A1, LA2, LA3, LB1, LB2, LB3, LV
The position and orientation of the front device 1A are calculated using the data of 1, LV2, LV3, and the like. At this time, the position and the posture are obtained as coordinate values of the XZ coordinate system with the rotation fulcrum of the boom 1a as the origin. The XZ coordinate system is an orthogonal coordinate system in a vertical plane fixed to the main body 1B.

When performing the setting calculation in the intrusion-prohibited area calculating section 9a, the front posture calculating section 9b calculates the values of the monitor points P1 to P5 as the Z coordinate values of the XZ coordinate system, and selects the most of them. A large value is set as the set value (Z coordinate value = Pcz) of the boundary of the intrusion prohibited area. 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, the front posture calculation section 9b calculates the positions of the monitor points P1 to P5 even during the work by the upper limit control. In this embodiment, three monitor points P1, P2, and P5 are used when performing the upper limit control.
The monitor point P1 is the apex of the bent portion of the boom 1a, the monitor point P2 is the upper end portion of the rear end of the arm 1b, and the monitor point P5 is a radius LV1 around the rotation center (bucket pin) of the bucket 1c. It is the highest point of the circle (distance from bucket pin to tip of bucket). Also at this time, the position of each monitor point is obtained as a value in the XZ coordinate system, and the height of each monitor point is XZ.
It is calculated as the Z coordinate value of the coordinate system.

Here, the Z coordinate values of the monitor points P1 to P5 calculated by the front posture calculation unit 9b are calculated from the rotation angles α, β, γ using the respective dimensions shown in FIG. 6 stored in the storage device. It is calculated by the following formula.

P1z = −LB2sinα + LB3cosα P2z = LA2sin (α + β) + LA3cos (α +
β) -LB1sinα P3z = -LV1sin (α + β + γ) -LA1sin
(Α + β) −LB1sinα P4z = −LV2sin (α + β + γ) + LV3cos
(Α + β + γ) -LA1sin (α + β) -LB1si
nα P5z = −LA1sin (α + β) −LB1sinα +
In the LV1 deceleration control calculation unit 9d, the Z coordinate values P1z, P2z, P5z of the monitor points P1, P2, P5 calculated by the front attitude calculation unit 9b and the boundary of the intrusion prohibition area stored in the limit value storage memory 9c are set. From the value Pcz and a distance (hereinafter, referred to as deceleration distance) LU and a deceleration function (to be described later) indicating a range of the deceleration area stored in the storage device of the control unit 9 in advance, the extension direction and the contraction direction of the boom cylinder 3a. , Deceleration command signals KBU1, KBD1, KAU1, KAD1 for the extension and contraction directions of the arm cylinder 3b are calculated. The contents of this calculation will be described below with reference to FIG.

First, monitor points P1, P2 and P5
P1z, P2z, and P5z are compared with each other, and the difference between the largest Z coordinate value and the set value Pcz of the boundary of the intrusion prohibition area is calculated, and the difference between the monitor point at the highest position and the boundary of the intrusion prohibition area is calculated. Calculate the distance LM between In FIG. 6, the distance LM is calculated assuming that the monitor point P2 is at the highest position. Next, this distance LM is compared with the deceleration distance LU, and if LM> LU, the monitor point at the highest position has not yet entered the deceleration area, so the deceleration command signals KBU1, KBD1, KAU1, KAD1 are all 1's.
To If LM≤LU, it is determined that the monitor point at the highest position is in the deceleration area, and the deceleration command signals KBU1, KBD1, KAU1, KAD1 are calculated from the following deceleration function.

KBU1 = LM / LU KBD1 = 1 KAU1 = LM / LU KAD1 = 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 KBD1 with respect to the extension direction of the boom cylinder 3a and the deceleration function of the deceleration command signals KAU1 and KAD1 with respect to the extension and contraction directions of the arm cylinder 3b are less than the deceleration distance LU. The deceleration command signal is set to linearly decrease from 1 to 0 as LM decreases.

In the maximum cylinder speed calculation unit 9e, the maximum cylinder speed VBU in the extension and contraction directions 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 the arm cylinder 3b, and deceleration command signals KBU1, KBD1 and KAU1, KAD1 calculated above. VBUmaxc, VBDmaxc and deceleration of arm cylinder 3b expansion and contraction operation Maximum cylinder speed VAUmaxc, VADma
Calculates xc. This arithmetic expression is shown below.

VBUmaxc = KBU1 × VBUmax VBDmaxc = KBD1 × VBDmax VAUmaxc = KAU1 × VAUmax VADmaxc = KAD1 × VADmax In the maximum pilot pressure calculation unit 9f, the deceleration maximum cylinder speeds VBUmaxc and VBD calculated by the maximum cylinder speed calculation unit 9e
Booms from maxc, VAUmaxc, VADmaxc and pilot pressure and cylinder speed tables as shown in FIGS. 9A, 9B, 9C and 9D 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.

The valve command calculator 9g calculates PBUmaxc, PBDmaxc, PAUmax calculated by the maximum pilot pressure calculator 9f.
c, PADmaxc and the pilot pressure and current value table previously stored in the storage unit of the control unit 9 as shown in FIG. 10, the extension / contraction operation of the boom cylinder 3a, the extension / contraction operation of the arm cylinder 3b, First for proportional solenoid valves 10a, 10b, 11a, 11b that regulate speed
The command current values iBU1, iBD1, iAU1, iAD1 are calculated.

On the other hand, the pilot primary pressure follow-up determination calculation unit 9
In h, the deceleration command signal K calculated by the deceleration control calculation unit 9d
It is determined whether each value of BU1, KAU1, and KAD1, that is, LM / LU is less than or equal to the coefficient Ktr stored in the storage unit of the control unit 9 in advance, and if LM / LU is less than or equal to Ktr, the proportional electromagnetic It is determined that the pilot primary pressure follow-up control (described later) for preventing the "spool adhesion phenomenon" of the valve is performed, and when it is greater than Ktr, it is determined that the control is not performed.

Here, Ktr is a coefficient for determining how close the front device 1A should approach the boundary of the intrusion prohibition region to start pilot primary pressure follow-up control, and Kt
When r is greater than 1, the pilot primary pressure follow-up control is started when the monitor point has not reached the deceleration region, and when Ktr is 1 or less, pilot primary pressure follow-up control is started when the monitor point has reached the deceleration region. It will be. Here, if Ktr is too much larger than 1,
The pilot primary pressure follow-up control may be started even though the monitor point may not reach the deceleration region, and the proportional solenoid valve may be unnecessarily throttled to hinder normal work (described later). Further, if Ktr is too smaller than 1 and becomes close to 0, the pilot primary pressure follow-up control may be started immediately before the boundary of the intrusion prohibition region, and the control may not work effectively. Ktr is determined in consideration of these factors, and it is usually preferable to start the monitor point at the same time when the monitor point reaches the deceleration region. Therefore, Ktr = 1 or a value near 1 is set. In the following, in this embodiment, Ktr
The description will be made assuming that = 1 is set.

In the pilot pressure calculation unit 9i, when the pilot primary pressure follow-up determination calculation unit 9h determines that the pilot primary pressure follow-up control is started with LM / LU≤Ktr, the pressure detectors 60a, 60b; 61a, 61b The detected pilot primary pressures of the proportional solenoid valves 10a, 10b, 11a, 11b (operating pilot pressures output from the pilot operating devices 4a, 4b) are used as pilot pressures PBU, PBD, PAU, P.
When AD calculation is performed and it is determined that pilot primary pressure follow-up control is not started with LM / LU> Ktr, the pilot source pressure of the pilot pump 43, that is, the operating pilot, is stored in advance in the storage device of the control unit 9. The maximum pressure that can be supplied as the pilot pressure is PBU, PBD, P
AU and PAD are calculated.

In the valve command calculation unit 9j, as in the valve command calculation unit 9g, the pilot pressures PBU, PBD, PAU, PAD are calculated from the pilot pressure and current value table shown in FIG.
Proportional solenoid valves 10a, 10b, 11a, 11 for obtaining
Second command current value iBU2, iBD2, iAU2, iAD2 for b
Is calculated.

In the minimum value judgment calculation unit 9k, the boom cylinder 3a extends and contracts, the arm cylinder 3b extends,
Proportional solenoid valves 10a, 10b, which regulate the speed of the contraction operation,
Command current values iBU, iB for output to 11a, 11b
D, iAU, iAD are determined according to the following equations.

IBU = min (iBU1, iBU2) iBD = min (iBD1, iBD2) iAU = min (iAU1, iAU2) iAD = min (iAD1, iAD2) The first command current value and the second command current value are equal. (IBU
1 = iBU2, iBD1 = iBD2, iAU1 = iAU2, iAD1 = iAD
2) In either case, it is determined in advance that one of them, for example, the first command current value is to be the command current value for output.

In the current output section 9m, iBU, iBD, iAU,
Proportional solenoid valve 10 with current value according to iAD as electric signal
a, 10b, 11a, 11b.

Here, the deceleration command signals calculated by the deceleration control calculator 9d are KBD = 1, KBU = 1, KAD = 1, KAU =
When it is 1, deceleration maximum pilot pressures PBUmaxc, PBDmaxc, PAUmaxc, P calculated by the maximum pilot pressure calculation unit 9f
ADmaxc is set to the maximum operating pilot pressure (pilot pump source pressure), and the pilot pressure calculation unit 9i calculates the pilot pressure when the deceleration control calculation unit 9d determines not to perform pilot primary pressure follow-up control. PBU, P
It is the same as BD, PAU, and PAD. Therefore, KBD = 1, K
First command current value i when BU = 1, KAD = 1, KAU = 1
BU1, iBD1, iAU1, iAD1 and second command current value iBU2, iB when it is determined not to perform pilot primary pressure tracking control
D2, iAU2, iAD2 are equal. Further, the command current values iBU, iBD for setting the deceleration maximum pilot pressures PBUmaxc, PBDmaxc, PAUmaxc, PADmaxc to the maximum pilot pressures
iAU and iAD are proportional solenoid valves 10a, 10b, 11a and 11
It is a current value that makes b fully open.

On the other hand, KBD = 0, KBU = 0, KAD = 0, K
When AU = 0, deceleration maximum pilot pressure PBUmaxc, PBDma
xc, PAUmaxc, PADmaxc are set to 0, and the command current values iBU, iBD, iAU, iAD at this time are proportional solenoid valve 1
It is a current value for fully closing 0a, 10b, 11a, 11b.

The above control flow is shown as a flow chart in FIGS. 11 and 12.

In FIG. 11, steps 400 and 410 correspond to the front posture calculation section 9b, and steps 200 and 500 to.
Reference numeral 530 corresponds to the deceleration control calculation unit 9d, step 540 corresponds to the maximum cylinder speed calculation unit 9e, and steps 600 to 62.
0 corresponds to the maximum pilot pressure calculation unit 9f, and the procedure 700
Corresponds to the valve command calculator 9g. Further, in FIG. 12, a procedure 800 is a pilot primary pressure follow-up determination calculation unit 9
Steps 900 to 920 correspond to the pilot pressure calculation unit 9i, step 1000 corresponds to the valve command calculation unit 9j, step 1100 corresponds to the minimum value determination calculation unit 9k, and steps 1200 and 1210 correspond to the current. It corresponds to the output unit 9m. In FIG. 11, steps 300 to 320 are initial settings 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
Alternatively, an electric pressure reducing valve that is provided between the pressure detecting device and the pressure detecting device may be provided as a pilot primary pressure output from the pilot operating device 4a or 4b and used as a pilot primary pressure to reduce and output the pilot primary pressure according to an electric signal. 60a, 60b or 6
1a, 61b are provided between the pilot operating device 4a or 4b and the electric pressure reducing valve 10a, 10b or 11a, 11b, and the electric pressure reducing valve 10a, 10b or 11a, 11
The deceleration control calculation unit 9d, the maximum cylinder speed calculation unit 9e, the maximum pilot pressure calculation unit 9f, and the valve command calculation unit 9g of the control unit 9 constitute the detection means for detecting the pilot primary pressure of b. The deceleration calculation means for calculating the first command current value is configured to become smaller as the distance to and decreases. Calculate a second command current value corresponding to the detected pilot primary pressure of the electric pressure reducing valve,
An output correction unit that outputs the smaller one of the first and second command current values as an electric signal is configured.

Further, the pilot primary pressure follow-up determination calculation section 9
h constitutes a judging means for judging whether or not the distance between the monitor point and the intrusion prohibition area is less than or equal to a predetermined value, and the pilot pressure calculating section 9i and the valve command calculating section 9j are judged by the judging means as being less than or equal to the predetermined value. Then, a value corresponding to the pilot primary pressure detected by the detecting means is calculated as the second command current value, and when the determining means determines that the distance is not less than or equal to the predetermined value, the maximum pressure of the operating pilot pressure is calculated. Comprising arithmetic means for calculating a value corresponding to as the second command current value.

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 P1 to P5 based on this input signal, and the deceleration control calculator 9d calculates the Z coordinate values P1z of the monitor points P1, P2 and P5 calculated by the front attitude calculator 9b. P2
From the difference between the largest Z coordinate value of z and P5z and the set value Pcz of the boundary of the intrusion prohibited area stored in the limit value storage memory 9c, the monitor point at the highest position, for example, the monitor point P2 and the intrusion prohibited area. The distance LM to the boundary is calculated, and this distance LM is compared with the deceleration distance LU to determine whether the monitor point P2 at the highest position is in the deceleration area.

At this time, when the front device 1A has not yet risen high and the monitor point P2 is far from the intrusion prohibited area, LM> LU, so the deceleration control calculation unit 9
At d, it is determined that the monitor point P2 is not in the deceleration area, and KBU1 = 1, KBD1 = 1, KAU1 = 1, KAD1 =
The deceleration command signal of 1 is generated.

On the other hand, at this time, the pilot operating device 4
The operation pilot pressure output from a and 4b (the pilot primary pressure of the proportional solenoid valves 10a and 11b) is the pressure detector 6
0a, 61b, and the detection signal is input to the pilot pressure calculator 9j of the control unit 9. Also,
In the control unit 9, the pilot primary pressure follow-up determination calculation unit 9h determines whether to perform pilot primary pressure follow-up control depending on whether LM / LU calculated by the deceleration control calculation unit 9d is Ktr (= 1) or less. . Since LM> LU now, LM / LU> 1, so it is determined that LM / LU is larger than Ktr and pilot primary pressure follow-up control is not performed, and the pilot pressure calculation unit 9i determines the maximum operation pilot pressure. The pressures are calculated as pilot pressures PBU, PBD, PAU, PAD, and the valve command calculators 9g, 9j perform the first command current values iBU1, iBD1, iAU1, iAD1 and the second command current values iBU2, iBD2, iAU2, iAD2. Are calculated as the same value, and one of them, for example, the first command current value is selected by the minimum value determination calculation unit 9k, and the command current values iBU, iBD,
iAU, iAD, proportional solenoid valves 10a, 10b, 11
Fully open a and 11b. As a result, the operating pilot pressure generated by the pilot operating devices 4a, 4b is not applied to the boom hydraulic control valve 5a and the arm hydraulic control valve 5b by the proportional solenoid valves 10a, 10b, 11a, 11b. It is transmitted as it is, and the front device 1A can be moved according to the operation of the operator.

When the front device 1A is raised and the monitor point P2 at the highest position reaches the deceleration area,
In the deceleration control calculation unit 9d, it is determined that the monitor point P2 has entered the deceleration region because LM ≦ LU, and deceleration command signals KBU1, KAU1, KAD1 smaller than 1 are generated from the deceleration function shown in FIG. 8 according to the distance LM.

On the other hand, in the pilot primary pressure follow-up determination calculation unit 9h of the control unit 9, LM / LU≤1 and LM
/ LU is equal to or lower than Ktr, it is determined to perform pilot primary pressure follow-up control, and the pilot pressure calculation unit 9i detects the pilots of the proportional solenoid valves 10a, 10b, 11a, 11b detected by the pressure detectors 60a, 60b; 61a, 61b. The primary pressure (the operating pilot pressure output from the pilot operating devices 4a, 4b) is calculated as the pilot pressures PBU, PBD, PAU, PAD. Then, in the minimum value determination calculation unit 9k,
The pilot primary pressures of the proportional solenoid valves 10a, 10b, 11a, 11b are deceleration maximum pilot pressures PBUmaxc, PBDmaxc, PAUmaxc, P calculated by the maximum pilot pressure calculator 9f.
While it is smaller than ADmaxc, the second command current values iBU2, iBD2, iAU2, iAD2 corresponding to the pilot primary pressure are set as command current values iBU, iBD, iAU, iAD for output, and the deceleration maximum pilot pressures PBUmaxc, PBDmaxc, PAUmaxc. , PADmaxc becomes smaller than the pilot primary pressure of the proportional solenoid valves 10a, 10b, 11a, 11b, the first command current values iBU1, iB
Command current values iBU, iBD, i for outputting D1, iAU1, iAD1
AU and iAD.

Therefore, the proportional solenoid valves 10a, 10b, 1
While the pilot primary pressure of 1a, 11b is smaller than the deceleration maximum pilot pressure PBUmaxc, PBDmaxc, PAUmaxc, PADmaxc, the proportional solenoid valves 10a, 10b, 11a, 11b are throttled to obtain the same pilot secondary pressure as the pilot primary pressure. To be In the present specification, this is referred to as "pilot primary pressure follow-up control". By such pilot primary pressure follow-up control, the pilot operating devices 4a and 4b are installed in the boom hydraulic control valve 5a and the arm hydraulic control valve 5b.
The operation pilot pressure generated in step 3 is transmitted almost as it is.

The deceleration maximum pilot pressure PBUmaxc,
When PADmaxc becomes smaller than the pilot primary pressure of the proportional solenoid valves 10a and 11b, the proportional solenoid valves 10a and 11b are throttled according to the first deceleration command signals iBU1 and iAD1 for deceleration control,
The boom raising and arm dump operating speeds are reduced. Further, when the deceleration control is performed in this manner, the proportional solenoid valve 10 is operated by the second command current value iBU2, iBD2, iAU2, iAD2 of the pilot primary pressure follow-up control as described above until then.
Since a and 11b are narrowed, the boom raising and arm dump operation speeds can be smoothly reduced without being affected by the "spool adhesion phenomenon" of the proportional solenoid valve.

When the front device 1A further rises and the monitor point P2 reaches the intrusion prohibition area, the deceleration control calculation unit 9d generates a deceleration command signal of KBU = 0, KAU = 0, KAD = 0, and the proportional solenoid valve. Fully close 10a, 11a and 11b, and stop the boom and arm. This stops the front device 1A.

The manner in which the influence is avoided by the "spool adhesion phenomenon" and the "pilot primary pressure follow-up control" of the proportional solenoid valve will be further described with reference to FIG. FIG. 13A shows a case where the pilot primary pressure follow-up control of the present invention is not performed, and FIG. 13B shows a case where the pilot primary pressure follow-up control is performed.

In FIG. 13A, when the operating pilot pressure (pilot primary pressure of the proportional solenoid valve) output from the pilot operating device is smaller than the maximum pilot pressure, the distance LM becomes less than or equal to LU and shifts to deceleration control. When
There is a period in which the command current value for deceleration control (command current value of the valve command calculation unit 9g) is too large for the pilot primary pressure of the proportional solenoid valve. During this period, when the pilot primary pressure follow-up control of the present invention is not performed, the pressure conversion value of the command current value for output to the proportional solenoid valve becomes larger than the pilot primary pressure, and the spool 153 of the proportional solenoid valve (see FIG. 4) The solenoid 156 (the same) is strongly pressed against the surface opposite to it, the pressure conversion value of the command current value becomes smaller than the pilot primary pressure, and even if the pressure starts to be reduced, the spool 153 does not move immediately, and for a moment. My movements get worse. That is, a "spool adhesion phenomenon" occurs.
When this phenomenon occurs, no matter how much the current value is reduced to reduce the pressure, the pressure reduction is momentarily delayed as shown by X in FIG. 13A, the start of the deceleration control is delayed, and the deceleration distance is apparently shortened. The same thing, which in some cases causes a large shock when the actuator stops,
This will make the operator uncomfortable. Further, when the bucket is loaded, the cargo may be spilled.

On the other hand, in the present invention, FIG.
As shown in, while the command current value of the deceleration control (command current value of the valve command calculation unit 9g) is too large with respect to the pilot primary pressure of the proportional solenoid valve, the second command current value (corresponding to the pilot primary pressure) ( Since the command current value of the valve command calculator 9j is calculated and the second command current value is output to the proportional solenoid valve, the pressure conversion value of the command current value for output to the proportional solenoid valve is almost equal to the pilot primary pressure. In the same manner, the command current value does not become too large with respect to the pilot primary pressure, and the influence of the "spool adhesion phenomenon" is mitigated. Therefore, the pressure reducing operation by the proportional solenoid valve is smoothly performed, and the actuator can be smoothly stopped.

Further, the distance LM between the monitor point and the intrusion prohibited area is a predetermined value determined by Ktr (K in the present embodiment.
Before tr = 1 and LM = deceleration distance LU) or less, the first command current value or the second command current value corresponding to the maximum pilot pressure is output, so the proportional solenoid valve is fully opened and pilot operation is performed. The operation pilot pressure generated by the device is transmitted to the hydraulic control valve with almost no resistance by the proportional solenoid valve, and the front device can be moved as if the proportional solenoid valve were not present.

As described above, according to this embodiment, the operating speed of the front device is gradually reduced as the monitor point approaches the intrusion prohibited area, and the operation speed of the front device becomes zero immediately before the intrusion prohibited area. The front member does not enter the prohibited area.

Further, the smaller one of the first command current value for deceleration control calculated according to the distance between the monitor point and the intrusion prohibition area and the second command current value corresponding to the pilot primary pressure of the proportional solenoid valve is selected. Therefore, when performing deceleration control, the current value does not become too large with respect to the pilot primary pressure of the proportional solenoid valve, and the influence of the "spool adhesion phenomenon" is mitigated. Therefore, the pressure reducing operation by the proportional solenoid valve is smoothly performed, and the actuator can be smoothly stopped. Therefore, the operator does not feel uncomfortable due to the impact at the time of stopping. Also, it is possible to prevent spillage.

Further, since the proportional solenoid valve is fully opened before the distance between the monitor point and the intrusion prohibition area is less than the deceleration distance LU, the front device can be moved as if the proportional solenoid valve were not provided. .

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, an angle meter that detects a rotation angle is used as a unit that detects 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.

[0067]

According to the present invention, the influence of the "spool adhesion phenomenon" of the electric pressure reducing valve can be mitigated.
The actuator can be stopped smoothly, and the operator does not feel uncomfortable due to the impact when stopping. Also, it is possible to prevent spillage.

Further, according to the present invention, the front device can be moved as if there is no proportional solenoid valve before the distance between the monitor point and the intrusion prohibition area becomes a predetermined value or less.

[Brief description of 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 method of setting a coordinate system and a region used in the work range restriction control of the present embodiment.

FIG. 7 is a diagram showing an intrusion prohibited area and a deceleration area in the work range restriction control according to the present embodiment.

FIG. 8 is a diagram showing a relationship between a deceleration command signal and a distance between a monitor point and an intrusion prohibited area in deceleration control calculation.

FIG. 9 is a diagram showing a relationship between pilot pressure and cylinder speed in a maximum pilot pressure calculation unit.

FIG. 10 is a diagram showing a relationship between a pilot pressure in a valve command calculation unit and a current value output to a proportional solenoid valve.

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

FIG. 12 is a flowchart showing the processing contents of the control unit.

FIG. 13 (a) is a diagram showing the influence of the "spool adhesion phenomenon" during deceleration control, and FIG. 13 (b) shows the "spool adhesion phenomenon" during deceleration control according to the present invention. It is a figure which shows the mitigation of an influence.

[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-4f Operation lever device 5a-5f Flow control valve 7 Setting device 8a-8c Angle detector (position detection means) 9 Control unit 9a Intrusion prohibited area calculator 9b Front posture calculator 9c Limit value storage memory 9d Deceleration control calculator 9e Maximum cylinder speed calculator 9f Maximum pilot pressure calculator 9g Valve command calculator 9h Pilot primary pressure follow-up calculator 9i Pilot pressure calculator 9j Valve command calculation part 9k Minimum value judgment calculation part 9m Current output part 10a-11b Proportional solenoid valve (electric pressure reducing valve) 50a-55b Hydraulic drive part 60a, 60b, 61a, 61b Pressure detector

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 which the first command current value is calculated and an electric signal is output,
In a work range limitation control device for a construction machine, which decelerates the front device when the monitor point approaches the intrusion prohibition region, and stops the front device when the monitoring point reaches the invasion prohibition region. And an associated plurality of flow control valves, and an electric pressure reducing valve that uses the operating pilot pressure output from the pilot operating device as a pilot primary pressure and reduces it according to the electric signal and outputs it. And a detection means provided between the pilot operating device and the electric pressure reducing valve for detecting the pilot primary pressure of the electric pressure reducing valve, and becomes smaller as the distance between the monitor point and the intrusion prohibition region becomes smaller. Deceleration calculation means for calculating the first command current value so that the electric reduction value detected by the detection means. Output correction means for calculating a second command current value corresponding to the pilot primary pressure of the pressure valve, and outputting the smaller one of the first and second command current values as the electric signal to the electric pressure reducing valve. A control device for limiting the working range of construction machinery. 2. The work range limitation control device for a construction machine according to claim 1, wherein the output correction means determines whether the distance between the monitor point and the intrusion prohibition area is a predetermined value or less, and When the determining means determines that the distance is less than or equal to a predetermined value, a value corresponding to the pilot primary pressure detected by the detecting means is calculated as the second command current value, and the determining means determines that the distance is not less than or equal to the predetermined value. A work range limiting control device for a construction machine, comprising: a calculating unit that calculates a value corresponding to the maximum pressure of the operation pilot pressure as the second command current value when determined. 3. The work range limiting control device for a construction machine according to claim 2, wherein the deceleration calculation means performs a calculation to reduce the first command current value when the monitor point reaches a preset deceleration region, The work range limiting control device for a construction machine, wherein the predetermined value of the distance determined by the determination means is set to be substantially equal to the distance in the deceleration region.